WorldWideScience

Sample records for warm season mortality

  1. Winter Season Mortality: Will Climate Warming Bring Benefits?

    Science.gov (United States)

    Kinney, Patrick L; Schwartz, Joel; Pascal, Mathilde; Petkova, Elisaveta; Tertre, Alain Le; Medina, Sylvia; Vautard, Robert

    2015-06-01

    Extreme heat events are associated with spikes in mortality, yet death rates are on average highest during the coldest months of the year. Under the assumption that most winter excess mortality is due to cold temperature, many previous studies have concluded that winter mortality will substantially decline in a warming climate. We analyzed whether and to what extent cold temperatures are associated with excess winter mortality across multiple cities and over multiple years within individual cities, using daily temperature and mortality data from 36 US cities (1985-2006) and 3 French cities (1971-2007). Comparing across cities, we found that excess winter mortality did not depend on seasonal temperature range, and was no lower in warmer vs. colder cities, suggesting that temperature is not a key driver of winter excess mortality. Using regression models within monthly strata, we found that variability in daily mortality within cities was not strongly influenced by winter temperature. Finally we found that inadequate control for seasonality in analyses of the effects of cold temperatures led to spuriously large assumed cold effects, and erroneous attribution of winter mortality to cold temperatures. Our findings suggest that reductions in cold-related mortality under warming climate may be much smaller than some have assumed. This should be of interest to researchers and policy makers concerned with projecting future health effects of climate change and developing relevant adaptation strategies.

  2. The importance of warm season warming to western U.S. streamflow changes

    Science.gov (United States)

    Das, T.; Pierce, D.W.; Cayan, D.R.; Vano, J.A.; Lettenmaier, D.P.

    2011-01-01

    Warm season climate warming will be a key driver of annual streamflow changes in four major river basins of the western U.S., as shown by hydrological model simulations using fixed precipitation and idealized seasonal temperature changes based on climate projections with SRES A2 forcing. Warm season (April-September) warming reduces streamflow throughout the year; streamflow declines both immediately and in the subsequent cool season. Cool season (October-March) warming, by contrast, increases streamflow immediately, partially compensating for streamflow reductions during the subsequent warm season. A uniform warm season warming of 3C drives a wide range of annual flow declines across the basins: 13.3%, 7.2%, 1.8%, and 3.6% in the Colorado, Columbia, Northern and Southern Sierra basins, respectively. The same warming applied during the cool season gives annual declines of only 3.5%, 1.7%, 2.1%, and 3.1%, respectively. Copyright 2011 by the American Geophysical Union.

  3. Small mammal use of native warm-season and non-native cool-season grass forage fields

    Science.gov (United States)

    Ryan L Klimstra,; Christopher E Moorman,; Converse, Sarah J.; Royle, J. Andrew; Craig A Harper,

    2015-01-01

    Recent emphasis has been put on establishing native warm-season grasses for forage production because it is thought native warm-season grasses provide higher quality wildlife habitat than do non-native cool-season grasses. However, it is not clear whether native warm-season grass fields provide better resources for small mammals than currently are available in non-native cool-season grass forage production fields. We developed a hierarchical spatially explicit capture-recapture model to compare abundance of hispid cotton rats (Sigmodon hispidus), white-footed mice (Peromyscus leucopus), and house mice (Mus musculus) among 4 hayed non-native cool-season grass fields, 4 hayed native warm-season grass fields, and 4 native warm-season grass-forb ("wildlife") fields managed for wildlife during 2 summer trapping periods in 2009 and 2010 of the western piedmont of North Carolina, USA. Cotton rat abundance estimates were greater in wildlife fields than in native warm-season grass and non-native cool-season grass fields and greater in native warm-season grass fields than in non-native cool-season grass fields. Abundances of white-footed mouse and house mouse populations were lower in wildlife fields than in native warm-season grass and non-native cool-season grass fields, but the abundances were not different between the native warm-season grass and non-native cool-season grass fields. Lack of cover following haying in non-native cool-season grass and native warm-season grass fields likely was the key factor limiting small mammal abundance, especially cotton rats, in forage fields. Retention of vegetation structure in managed forage production systems, either by alternately resting cool-season and warm-season grass forage fields or by leaving unharvested field borders, should provide refugia for small mammals during haying events.

  4. Ocean warming and acidification synergistically increase coral mortality

    Science.gov (United States)

    Prada, F.; Caroselli, E.; Mengoli, S.; Brizi, L.; Fantazzini, P.; Capaccioni, B.; Pasquini, L.; Fabricius, K. E.; Dubinsky, Z.; Falini, G.; Goffredo, S.

    2017-01-01

    Organisms that accumulate calcium carbonate structures are particularly vulnerable to ocean warming (OW) and ocean acidification (OA), potentially reducing the socioeconomic benefits of ecosystems reliant on these taxa. Since rising atmospheric CO2 is responsible for global warming and increasing ocean acidity, to correctly predict how OW and OA will affect marine organisms, their possible interactive effects must be assessed. Here we investigate, in the field, the combined temperature (range: 16-26 °C) and acidification (range: pHTS 8.1-7.4) effects on mortality and growth of Mediterranean coral species transplanted, in different seasonal periods, along a natural pH gradient generated by a CO2 vent. We show a synergistic adverse effect on mortality rates (up to 60%), for solitary and colonial, symbiotic and asymbiotic corals, suggesting that high seawater temperatures may have increased their metabolic rates which, in conjunction with decreasing pH, could have led to rapid deterioration of cellular processes and performance. The net calcification rate of the symbiotic species was not affected by decreasing pH, regardless of temperature, while in the two asymbiotic species it was negatively affected by increasing acidification and temperature, suggesting that symbiotic corals may be more tolerant to increasing warming and acidifying conditions compared to asymbiotic ones.

  5. Regional seasonal warming anomalies and land-surface feedbacks

    Science.gov (United States)

    Coffel, E.; Horton, R. M.

    2017-12-01

    Significant seasonal variations in warming are projected in some regions, especially central Europe, the southeastern U.S., and central South America. Europe in particular may experience up to 2°C more warming during June, July, and August than in the annual mean, enhancing the risk of extreme summertime heat. Previous research has shown that heat waves in Europe and other regions are tied to seasonal soil moisture variations, and that in general land-surface feedbacks have a strong effect on seasonal temperature anomalies. In this study, we show that the seasonal anomalies in warming are also due in part to land-surface feedbacks. We find that in regions with amplified warming during the hot season, surface soil moisture levels generally decline and Bowen ratios increase as a result of a preferential partitioning of incoming energy into sensible vs. latent. The CMIP5 model suite shows significant variability in the strength of land-atmosphere coupling and in projections of future precipitation and soil moisture. Due to the dependence of seasonal warming on land-surface processes, these inter-model variations influence the projected summertime warming amplification and contribute to the uncertainty in projections of future extreme heat.

  6. Establishing native warm season grasses on Eastern Kentucky strip mines

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Forestry

    1998-12-31

    The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat.

  7. Establishing native warm season grasses on Eastern Kentucky strip mines

    International Nuclear Information System (INIS)

    Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

    1998-01-01

    The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat

  8. Comparative growth analysis of cool- and warm-season grasses in a cool-temperate environment

    International Nuclear Information System (INIS)

    Belesky, D.P.; Fedders, J.M.

    1995-01-01

    Using both cool-season (C3) and warm-season (C4) species is a viable means of optimizing herbage productivity over varying climatic conditions in temperate environments. Despite well-documented differences in water, N, and radiation use, no consistent evidence demonstrates productivity differences among C3 and C4 perennial grass species under identical management. A field study was conducted to determine relative growth rates (RGR), nitrogen productivity (NP), and mean radiation productivity (RP) (dry matter production as a function of incident radiation) of cool- and warm-season grasses managed identically. Results were used to identify management practices thd could lead to optimal productivity in combinations or mixtures of cool- and warm-season grasses. Dry matter yields of warm-season grasses equaled or surpassed those of cool-season grasses, despite a 40% shorter growth interval. Certain cool- and warm-season grasses appear to be suitable for use in mixtures, based on distribution of herbage production; however, actual compatibility may be altered by defoliation management. Relative growth rates varied among years and were about 40% lower for canopies clipped to a 10-cm residue height each time 20-cm of growth accumulated compared with other treatments. The RGR of warm-season grasses was twice that of cool-season grasses Nitrogen productivity (g DM g-1 N d -1) and mean radiation productivity (g DM MJ-1) for warm-season grasses was also more than twice that of cool-season grasses. Radiation productivity of cool-season grasses was dependent on N, while this was not always the case for warm-season grasses. The superior production capability of certain warm-season compared with cool-season grasses in a cool-temperate environment can be sustained under a range of defoliation treatments and demonstrates suitability for use in frequently defoliated situations

  9. Seasonality in mortality and its relationship to temperature among the older population in Hanoi, Vietnam

    Directory of Open Access Journals (Sweden)

    Le Thi Thanh Xuan

    2014-12-01

    Full Text Available Background: Several studies have established a relationship between temperature and mortality. In particular, older populations have been shown to be vulnerable to temperature effects. However, little information exists on the temperature–mortality relationship in Vietnam. Objectives: This article aims to examine the monthly temperature–mortality relationship among older people in Hanoi, Vietnam, over the period between 2005 and 2010, and estimate seasonal patterns in mortality. Methods: We employed Generalized Additive Models, including smooth functions, to model the temperature–mortality relationships. A quasi-Poisson distribution was used to model overdispersion of death counts. Temporal trends, seasonality, and population size were adjusted for while estimating changes in monthly mortality over the study period. A cold month was defined as a month with a mean temperature below 19°C. Results: This study found that the high peak of mortality coincided with low temperatures in the month of February 2008, during which the mean temperature was the lowest in the whole study period. There was a significant relationship between mean monthly temperature and mortality among the older people (p<0.01. Overall, there was a significant decrease in the number of deaths in the year 2009 during the study period. There was a 21% increase in the number of deaths during the cold season compared to the warm season. The increase in mortality during the cold period was higher among females compared to males (female: IRR [incidence relative risk] =1.23; male: IRR=1.18. Conclusions: Cold temperatures substantially increased mortality among the older population in Hanoi, Vietnam, and there were gender differences. Necessary preventive measures are required to mitigate temperature effects with greater attention to vulnerable groups.

  10. Seasonal variation in child mortality in rural Guinea-Bissau.

    Science.gov (United States)

    Nielsen, Bibi Uhre; Byberg, Stine; Aaby, Peter; Rodrigues, Amabelia; Benn, Christine Stabell; Fisker, Ane Baerent

    2017-07-01

    In many African countries, child mortality is higher in the rainy season than in the dry season. We investigated the effect of season on child mortality by time periods, sex and age in rural Guinea-Bissau. Bandim health project follows children under-five in a health and demographic surveillance system in rural Guinea-Bissau. We compared the mortality in the rainy season (June to November) between 1990 and 2013 with the mortality in the dry season (December to May) in Cox proportional hazards models providing rainy vs. dry season mortality rate ratios (r/d-mrr). Seasonal effects were estimated in strata defined by time periods with different frequency of vaccination campaigns, sex and age (<1 month, 1-11 months, 12-59 months). Verbal autopsies were interpreted using InterVa-4 software. From 1990 to 2013, overall mortality was declined by almost two-thirds among 81 292 children (10 588 deaths). Mortality was 51% (95% ci: 45-58%) higher in the rainy season than in the dry season throughout the study period. The seasonal difference increased significantly with age, the r/d-mrr being 0.94 (0.86-1.03) among neonates, 1.57 (1.46-1.69) in post-neonatal infants and 1.83 (1.72-1.95) in under-five children (P for same effect <0.001). According to the InterVa, malaria deaths were the main reason for the seasonal mortality difference, causing 50% of all deaths in the rainy season, but only if the InterVa included season of death, making the argument self-confirmatory. The mortality declined throughout the study, yet rainy season continued to be associated with 51% higher overall mortality. © 2017 The Authors. Tropical Medicine & International Health Published by John Wiley & Sons Ltd.

  11. Warming and Acidification Induced Mass Mortality of a Coastal Keystone predator

    Science.gov (United States)

    Melzner, F.; Findeisen, U.

    2016-02-01

    The Baltic Sea is characterized by low salinity and pronounced fluctuations in pCO2. On-line monitoring of pCO2 in 2014 in Kiel Fjord demonstrated occurrence of peak values of >2,000 µatm in summer and autumn and average values >750 µatm. We assessed the impacts of elevated temperature (ambient temperature, ambient +3°C) and pCO2 (500, 1,500, 2,400 µatm) on the keystone species Asterias rubens in a fully crossed long - term experiment (N=5 replicate tanks each, 1 year duration). During spring and early summer (February - June), high temperature animals ingested significantly more food and spawned significantly earlier (April 30th) than ambient acclimated animals (May 23rd). Elevated pCO2 led to comparatively minor reductions in food intake and scope for growth during that period. During summer (June - August), elevated temperature >25°C caused negative energy budgets and >95% mortality in the warm acclimated groups, while mortality was low in the ambient temperature groups. Our results indicate that A. rubens may benefit from increased temperature during colder months, yet dramatically suffer during summer heat waves in warm years. Meaningful experimental approaches to assess species vulnerability to climate change need to encompass all seasons and realistic abiotic stressor levels.

  12. Performances of some warm-season turfgrasses under ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-15

    Sep 15, 2009 ... Main characteristics of mediterranean climate are represented by mild, rainy ... the warm-season turfgrasses with low water use rate and. *Corresponding ..... Lawns and Golf, Sleeping Bear Press, Chelsea, MI. Busey P (2003).

  13. Responses of Seasonal Precipitation Intensity to Global Warming

    Science.gov (United States)

    Lan, Chia-Wei; Lo, Min-Hui; Chou, Chia

    2016-04-01

    Under global warming, the water vapor increases with rising temperature at the rate of 7%/K. Most previous studies focus on the spatial differences of precipitation and suggest that wet regions become wetter and dry regions become drier. Our recent studies show a temporal disparity of global precipitation, which the wet season becomes wetter and dry season becomes drier; therefore, the annual range increases. However, such changes in the annual range are not homogeneous globally, and in fact, the drier trend over the ocean is much larger than that over the land, where the dry season does not become drier. Such precipitation change over land is likely because of decreased omega at 500hPa (more upward motion) in the reanalysis datasets from 1980 to 2013. The trends of vertical velocity and moist static energy profile over the increased precipitation regions become more unstable. The instability is most likely attributed to the change in specific humility below 400hPa. Further, we will use Coupled Model Intercomparison Project Phase 5 (CMIP5) archives to investigate whether the precipitation responses in dry season are different between the ocean and land under global warming.

  14. Projections of Seasonal Patterns in Temperature- Related Deaths for Manhattan, New York

    Science.gov (United States)

    Li, Tiantian; Horton, Radley M.; Kinney, Patrick L.

    2013-01-01

    Global average temperatures have been rising for the past half-century, and the warming trend has accelerated in recent decades. Further warming is expected over the next few decades, with significant regional variations. These warming trends will probably result in more frequent, intense and persistent periods of hot temperatures in summer, and generally higher temperatures in winter. Daily death counts in cities increase markedly when temperatures reach levels that are very high relative to what is normal in a given location. Relatively cold temperatures also seem to carry risk. Rising temperatures may result in more heat-related mortality but may also reduce cold-related mortality, and the net impact on annual mortality remains uncertain. Here we use 16 downscaled global climate models and two emissions scenarios to estimate present and future seasonal patterns in temperature-related mortality in Manhattan, New York. All 32 projections yielded warm-season increases and cold-season decreases in temperature-related mortality, with positive net annual temperature-related deaths in all cases. Monthly analyses showed that the largest percentage increases may occur in May and September. These results suggest that, over a range of models and scenarios of future greenhouse gas emissions, increases in heat-related mortality could outweigh reductions in cold-related mortality, with shifting seasonal patterns.

  15. Role of Acclimatization in Weather-Related Human Mortality During the Transition Seasons of Autumn and Spring in a Thermally Extreme Mid-Latitude Continental Climate

    Science.gov (United States)

    de Freitas, Christopher R.; Grigorieva, Elena A.

    2015-01-01

    Human mortality is closely related to natural climate-determined levels of thermal environmental stress and the resulting thermophysiological strain. Most climate-mortality research has focused on seasonal extremes during winter and summer when mortality is the highest, while relatively little attention has been paid to mortality during the transitional seasons of autumn and spring. The body acclimatizes to heat in the summer and cold in winter and readjusts through acclimatization during the transitions between the two during which time the body experiences the thermophysiological strain of readjustment. To better understand the influences of weather on mortality through the acclimatization process, the aim here is to examine the periods that link very cold and very warms seasons. The study uses the Acclimatization Thermal Strain Index (ATSI), which is a comparative measure of short-term thermophysiological impact on the body. ATSI centers on heat exchange with the body’s core via the respiratory system, which cannot be protected. The analysis is based on data for a major city in the climatic region of the Russian Far East characterized by very hot summers and extremely cold winters. The results show that although mortality peaks in winter (January) and is at its lowest in summer (August), there is not a smooth rise through autumn nor a smooth decline through spring. A secondary peak occurs in autumn (October) with a smaller jump in May. This suggests the acclimatization from warm-to-cold produces more thermophysiological strain than the transition from cold-to-warm. The study shows that ATSI is a useful metric for quantifying the extent to which biophysical adaptation plays a role in increased strain on the body during re-acclimatization and for this reason is a more appropriate climatic indictor than air temperature alone. The work gives useful bioclimatic information on risks involved in transitional seasons in regions characterized by climatic extremes. This

  16. Seasonal mortality variations of cardiovascular, respiratory and malignant diseases in the City of Belgrade

    Directory of Open Access Journals (Sweden)

    Stanišić-Stojić Svetlana

    2016-01-01

    cardiovascular diseases increased twice, namely at the end of June and October, which is assumed to be the result of sudden temperature changes. Nonetheless, no such seasonal variations were observed in mortality caused by cancer. Seasonal variations in mortality resulting from cardiovascular diseases also indicate gender differences, which is why sudden temperature changes in interim periods affect more women than men. As regards deseasonalized trend, mortality caused by cardiovascular diseases stagnates, while mortality caused by cancer and mortality caused by respiratory diseases records moderate to severe increase. This is a uniform trend in almost all municipalities in Belgrade, with average mortality rates being higher in central zones than in suburbs over the last 15 years, particularly mortality caused by cancer. A slight increase in the overall mortality can also be attributed to aging of the population, which cannot be verified due to lack of available accurate data on the average age structure of Belgrade population for the observed period. A better understanding of seasonal variations in mortality caused by chronic non-communicable diseases can contribute to improving the population health care and rising awareness of the population concerning greater health care in changeable weather conditions due to global warming and climate change. These findings can also enhance preventive action on environmental risk factors that are not limited exclusively to weather conditions, such as air pollution.

  17. Seasonal variation in child mortality in rural Guinea-Bissau

    DEFF Research Database (Denmark)

    Nielsen, Bibi Uhre; Byberg, Stine; Aaby, Peter

    2017-01-01

    Objectives: In many African countries, child mortality is higher in the rainy season than in the dry season. We investigated the effect of season on child mortality by time periods, sex and age in rural Guinea-Bissau. Methods: Bandim health project follows children under-five in a health...

  18. Warm-season severe wind events in Germany

    Science.gov (United States)

    Gatzen, Christoph

    2013-04-01

    A 15-year data set of wind measurements was analyzed with regard to warm season severe wind gusts in Germany. For April to September of the years 1997 to 2011, 1035 wind measurements of 26 m/s or greater were found. These wind reports were associated with 268 wind events. In total, 252 convective wind events contributed to 837 (81%) of the wind reports, 16 non-convective synoptic-scale wind events contributed to 198 reports (19%). Severe wind events were found with synoptic situations characterized by rather strong mid-level flow and advancing mid-level troughs. Severe convective wind events were analyzed using radar images and classified with respect to the observed radar structure. The most important convective mode was squall lines that were associated with one third of all severe wind gusts, followed by groups, bow echo complexes, and bow echoes. Supercells and cells were not associated with many wind reports. The low contribution of isolated cells indicates that rather large-scale forcing by synoptic-scale features like fronts is important for German severe wind events. Bow echoes were found to be present for 58% of all wind reports. The movement speed of bow echoes indicated a large variation with a maximum speed of 33 m/s. Extreme wind events as well as events with more than 15 wind reports were found to be related to higher movement speeds. Concentrating on the most intense events, derechos seem to be very important to the warm season wind threat in Germany. Convective events with a path length of more than 400 km contributed to 36% of all warm-season wind gusts in this data set. Furthermore, eight of nine extreme gusts exceeding 40 m/s were recorded with derecho events.

  19. Warm season chloride concentrations in stream habitats of freshwater mussel species at risk

    International Nuclear Information System (INIS)

    Todd, Aaron K.; Kaltenecker, M. Georgina

    2012-01-01

    Warm season (May–October) chloride concentrations were assessed in stream habitats of freshwater mussel species at risk in southern Ontario, Canada. Significant increases in concentrations were observed at 96% of 24 long-term (1975–2009) monitoring sites. Concentrations were described as a function of road density indicating an anthropogenic source of chloride. Linear regression showed that 36% of the variation of concentrations was explained by road salt use by the provincial transportation ministry. Results suggest that long-term road salt use and retention is contributing to a gradual increase in baseline chloride concentrations in at risk mussel habitats. Exposure of sensitive mussel larvae (glochidia) to increasing chloride concentrations may affect recruitment to at risk mussel populations. - Highlights: ► Warm season chloride concentrations were assessed in habitats of mussel species at risk. ► Concentrations increased significantly at 96% of 24 long-term monitoring sites. ► Concentrations increased with increases in road density and road salt use. ► Retention of road salt likely contributed to elevated warm season concentrations. ► Glochidia exposure to increasing concentrations may affect mussel reproduction. - Warm season chloride concentrations increased in southern Ontario streams with road salt use, such that reproduction of freshwater mussel species at risk may be affected.

  20. A new mechanism for warm-season precipitation response to global warming based on convection-permitting simulations

    Science.gov (United States)

    Dai, Aiguo; Rasmussen, Roy M.; Liu, Changhai; Ikeda, Kyoko; Prein, Andreas F.

    2017-08-01

    Climate models project increasing precipitation intensity but decreasing frequency as greenhouse gases increase. However, the exact mechanism for the frequency decrease remains unclear. Here we investigate this by analyzing hourly data from regional climate change simulations with 4 km grid spacing covering most of North America using the Weather Research and Forecasting model. The model was forced with present and future boundary conditions, with the latter being derived by adding the CMIP5 19-model ensemble mean changes to the ERA-interim reanalysis. The model reproduces well the observed seasonal and spatial variations in precipitation frequency and histograms, and the dry interval between rain events over the contiguous US. Results show that overall precipitation frequency indeed decreases during the warm season mainly due to fewer light-moderate precipitation (0.1 2.0 mm/h) events, while heavy (2 10 mm/h) events increase. Dry spells become longer and more frequent, together with a reduction in time-mean relative humidity (RH) in the lower troposphere during the warm season. The increased dry hours and decreased RH lead to a reduction in overall precipitation frequency and also for light-moderate precipitation events, while water vapor-induced increases in precipitation intensity and the positive latent heating feedback in intense storms may be responsible for the large increase in intense precipitation. The size of intense storms increases while their number decreases in the future climate, which helps explain the increase in local frequency of heavy precipitation. The results generally support a new hypothesis for future warm-season precipitation: each rainstorm removes ≥7% more moisture from the air per 1 K local warming, and surface evaporation and moisture advection take slightly longer than currently to replenish the depleted moisture before the next storm forms, leading to longer dry spells and a reduction in precipitation frequency, as well as

  1. Striking Seasonality in the Secular Warming of the Northern Continents: Structure and Mechanisms

    Science.gov (United States)

    Nigam, S.; Thomas, N. P.

    2017-12-01

    The linear trend in twentieth-century surface air temperature (SAT)—a key secular warming signal— exhibits striking seasonal variations over Northern Hemisphere continents; SAT trends are pronounced in winter and spring but notably weaker in summer and fall. The SAT trends in historical twentieth-century climate simulations informing the Intergovernmental Panel for Climate Change's Fifth Assessment show varied (and often unrealistic) strength and structure, and markedly weaker seasonal variation. The large intra-ensemble spread of winter SAT trends in some historical simulations was surprising, especially in the context of century-long linear trends, with implications for the detection of the secular warming signal. The striking seasonality of observed secular warming over northern continents warrants an explanation and the representation of related processes in climate models. Here, the seasonality of SAT trends over North America is shown to result from land surface-hydroclimate interactions and, to an extent, also from the secular change in low-level atmospheric circulation and related thermal advection. It is argued that the winter dormancy and summer vigor of the hydrologic cycle over middle- to high-latitude continents permit different responses to the additional incident radiative energy from increasing greenhouse gas concentrations. The seasonal cycle of climate, despite its monotony, provides an expanded phase space for the exposition of the dynamical and thermodynamical processes generating secular warming, and an exceptional cost-effective opportunity for benchmarking climate projection models.

  2. Season, sex, age, and education as modifiers of the effects of outdoor air pollution on daily mortality in Shanghai, China: The Public Health and Air Pollution in Asia (PAPA) Study.

    Science.gov (United States)

    Kan, Haidong; London, Stephanie J; Chen, Guohai; Zhang, Yunhui; Song, Guixiang; Zhao, Naiqing; Jiang, Lili; Chen, Bingheng

    2008-09-01

    Various factors can modify the health effects of outdoor air pollution. Prior findings about modifiers are inconsistent, and most of these studies were conducted in developed countries. We conducted a time-series analysis to examine the modifying effect of season, sex, age, and education on the association between outdoor air pollutants [particulate matter air pollution for the warm season (April-September) and cool season (October-March) separately. For total mortality, we examined the association stratified by sex and age. Stratified analysis by educational attainment was conducted for total, cardiovascular, and respiratory mortality. Outdoor air pollution was associated with mortality from all causes and from cardiorespiratory diseases in Shanghai. An increase of 10 mug/m(3) in a 2-day average concentration of PM(10), SO(2), NO(2), and O(3) corresponds to increases in all-cause mortality of 0.25% [95% confidence interval (CI), 0.14-0.37), 0.95% (95% CI, 0.62-1.28), 0.97% (95% CI, 0.66-1.27), and 0.31% (95% CI, 0.04-0.58), respectively. The effects of air pollutants were more evident in the cool season than in the warm season, and females and the elderly were more vulnerable to outdoor air pollution. Effects of air pollution were generally greater in residents with low educational attainment (illiterate or primary school) compared with those with high educational attainment (middle school or above). Season, sex, age, and education may modify the health effects of outdoor air pollution in Shanghai. These findings provide new information about the effects of modifiers on the relationship between daily mortality and air pollution in developing countries and may have implications for local environmental and social policies.

  3. The impact of global warming on seasonality of ocean primary production

    Directory of Open Access Journals (Sweden)

    S. Henson

    2013-06-01

    Full Text Available The seasonal cycle (i.e. phenology of oceanic primary production (PP is expected to change in response to climate warming. Here, we use output from 6 global biogeochemical models to examine the response in the seasonal amplitude of PP and timing of peak PP to the IPCC AR5 warming scenario. We also investigate whether trends in PP phenology may be more rapidly detectable than trends in annual mean PP. The seasonal amplitude of PP decreases by an average of 1–2% per year by 2100 in most biomes, with the exception of the Arctic which sees an increase of ~1% per year. This is accompanied by an advance in the timing of peak PP by ~0.5–1 months by 2100 over much of the globe, and particularly pronounced in the Arctic. These changes are driven by an increase in seasonal amplitude of sea surface temperature (where the maxima get hotter faster than the minima and a decrease in the seasonal amplitude of the mixed layer depth and surface nitrate concentration. Our results indicate a transformation of currently strongly seasonal (bloom forming regions, typically found at high latitudes, into weakly seasonal (non-bloom regions, characteristic of contemporary subtropical conditions. On average, 36 yr of data are needed to detect a climate-change-driven trend in the seasonal amplitude of PP, compared to 32 yr for mean annual PP. Monthly resolution model output is found to be inadequate for resolving phenological changes. We conclude that analysis of phytoplankton seasonality is not necessarily a shortcut to detecting climate change impacts on ocean productivity.

  4. The responses of microbial temperature relationships to seasonal change and winter warming in a temperate grassland.

    Science.gov (United States)

    Birgander, Johanna; Olsson, Pål Axel; Rousk, Johannes

    2018-01-18

    Microorganisms dominate the decomposition of organic matter and their activities are strongly influenced by temperature. As the carbon (C) flux from soil to the atmosphere due to microbial activity is substantial, understanding temperature relationships of microbial processes is critical. It has been shown that microbial temperature relationships in soil correlate with the climate, and microorganisms in field experiments become more warm-tolerant in response to chronic warming. It is also known that microbial temperature relationships reflect the seasons in aquatic ecosystems, but to date this has not been investigated in soil. Although climate change predictions suggest that temperatures will be mostly affected during winter in temperate ecosystems, no assessments exist of the responses of microbial temperature relationships to winter warming. We investigated the responses of the temperature relationships of bacterial growth, fungal growth, and respiration in a temperate grassland to seasonal change, and to 2 years' winter warming. The warming treatments increased winter soil temperatures by 5-6°C, corresponding to 3°C warming of the mean annual temperature. Microbial temperature relationships and temperature sensitivities (Q 10 ) could be accurately established, but did not respond to winter warming or to seasonal temperature change, despite significant shifts in the microbial community structure. The lack of response to winter warming that we demonstrate, and the strong response to chronic warming treatments previously shown, together suggest that it is the peak annual soil temperature that influences the microbial temperature relationships, and that temperatures during colder seasons will have little impact. Thus, mean annual temperatures are poor predictors for microbial temperature relationships. Instead, the intensity of summer heat-spells in temperate systems is likely to shape the microbial temperature relationships that govern the soil-atmosphere C

  5. Seasonality of change: Summer warming rates do not fully represent effects of climate change on lake temperatures

    Science.gov (United States)

    Winslow, Luke; Read, Jordan S.; Hansen, Gretchen J. A.; Rose, Kevin C.; Robertson, Dale M.

    2017-01-01

    Responses in lake temperatures to climate warming have primarily been characterized using seasonal metrics of surface-water temperatures such as summertime or stratified period average temperatures. However, climate warming may not affect water temperatures equally across seasons or depths. We analyzed a long-term dataset (1981–2015) of biweekly water temperature data in six temperate lakes in Wisconsin, U.S.A. to understand (1) variability in monthly rates of surface- and deep-water warming, (2) how those rates compared to summertime average trends, and (3) if monthly heterogeneity in water temperature trends can be predicted by heterogeneity in air temperature trends. Monthly surface-water temperature warming rates varied across the open-water season, ranging from 0.013 in August to 0.073°C yr−1 in September (standard deviation [SD]: 0.025°C yr−1). Deep-water trends during summer varied less among months (SD: 0.006°C yr−1), but varied broadly among lakes (–0.056°C yr−1 to 0.035°C yr−1, SD: 0.034°C yr−1). Trends in monthly surface-water temperatures were well correlated with air temperature trends, suggesting monthly air temperature trends, for which data exist at broad scales, may be a proxy for seasonal patterns in surface-water temperature trends during the open water season in lakes similar to those studied here. Seasonally variable warming has broad implications for how ecological processes respond to climate change, because phenological events such as fish spawning and phytoplankton succession respond to specific, seasonal temperature cues.

  6. Cool seasons are related to poor prognosis in patients with infective endocarditis

    Science.gov (United States)

    Chen, Su-Jung; Chao, Tze-Fan; Lin, Yenn-Jiang; Lo, Li-Wei; Hu, Yu-Feng; Tuan, Ta-Chuan; Hsu, Tsui-Lieh; Yu, Wen-Chung; Leu, Hsin-Bang; Chang, Shih-Lin; Chen, Shih-Ann

    2012-09-01

    Many cardiac diseases demonstrate seasonal variations in the incidence and mortality. This study was designed to investigate whether the mortality of infective endocarditis (IE) was higher in cool seasons and to evaluate the effects of cool climate for IE. We enrolled 100 IE patients with vegetations in our hospital. The temperatures of the IE episodes were defined as the monthly average temperatures of the admission days. The average temperatures in the cool (fall/winter) and warm seasons (spring/summer) were 19.2°C and 27.6°C, respectively. In addition, patients admitted with the diagnosis of IE were identified from the National Health Insurance Research Database (NHIRD) and the in-hospital mortality rates in cool and warm seasons were compared to validate the findings derived from the data of our hospital. The mortality rate for IE was significantly higher in fall/winter than in spring/summer which presents consistently in the patient population of our hospital (32.7% versus 12.5%, p = 0.017) and from NHIRD (10.4% versus 4.6%, p = 0.019). IE episodes which occurred during cool seasons presented with a higher rate of heart failure (44.2% versus 22.9%, p = 0.025) and D-dimer level (5.5 ± 3.8 versus 2.4 ± 1.8 μg/ml, p = 0.017) at admission than that of warm seasons. These results may reflect the impact of temperatures during the pre-hospitalized period on the disease process. In the multivariate analysis, Staphylococcal infection, left ventricular hypertrophy, left ventricular systolic dysfunction and temperature were the independent predictors of mortalities in IE patients.

  7. Characterization of water quality and suspended sediment during cold-season flows, warm-season flows, and stormflows in the Fountain and Monument Creek watersheds, Colorado, 2007–2015

    Science.gov (United States)

    Miller, Lisa D.; Stogner, Sr., Robert W.

    2017-09-01

    From 2007 through 2015, the U.S. Geological Survey, in cooperation with Colorado Springs City Engineering, conducted a study in the Fountain and Monument Creek watersheds, Colorado, to characterize surface-water quality and suspended-sediment conditions for three different streamflow regimes with an emphasis on characterizing water quality during storm runoff. Data collected during this study were used to evaluate the effects of stormflows and wastewater-treatment effluent discharge on Fountain and Monument Creeks in the Colorado Springs, Colorado, area. Water-quality samples were collected at 2 sites on Upper Fountain Creek, 2 sites on Monument Creek, 3 sites on Lower Fountain Creek, and 13 tributary sites during 3 flow regimes: cold-season flow (November–April), warm-season flow (May–October), and stormflow from 2007 through 2015. During 2015, additional samples were collected and analyzed for Escherichia coli (E. coli) during dry weather conditions at 41 sites, located in E. coli impaired stream reaches, to help identify source areas and scope of the impairment.Concentrations of E. coli, total arsenic, and dissolved copper, selenium, and zinc in surface-water samples were compared to Colorado in-stream standards. Stormflow concentrations of E. coli frequently exceeded the recreational use standard of 126 colonies per 100 milliliters at main-stem and tributary sites by more than an order of magnitude. Even though median E. coli concentrations in warm-season flow samples were lower than median concentrations in storm-flow samples, the water quality standard for E. coli was still exceeded at most main-stem sites and many tributary sites during warm-season flows. Six samples (three warm-season flow and three stormflow samples) collected from Upper Fountain Creek, upstream from the confluence of Monument Creek, and two stormflow samples collected from Lower Fountain Creek, downstream from the confluence with Monument Creek, exceeded the acute water

  8. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    Directory of Open Access Journals (Sweden)

    Guo-Liang Xu

    Full Text Available Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm increased, but the percentage of large mites (body length >0.40 mm decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  9. Seasonal Exposure to Drought and Air Warming Affects Soil Collembola and Mites

    Science.gov (United States)

    Xu, Guo-Liang; Kuster, Thomas M.; Günthardt-Goerg, Madeleine S.; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4°C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type. PMID:22905210

  10. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    Science.gov (United States)

    Xu, Guo-Liang; Kuster, Thomas M; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  11. Chronic environmental stress enhances tolerance to seasonal gradual warming in marine mussels.

    Directory of Open Access Journals (Sweden)

    Ionan Marigómez

    Full Text Available In global climate change scenarios, seawater warming acts in concert with multiple stress sources, which may enhance the susceptibility of marine biota to thermal stress. Here, the responsiveness to seasonal gradual warming was investigated in temperate mussels from a chronically stressed population in comparison with a healthy one. Stressed and healthy mussels were subjected to gradual temperature elevation for 8 days (1°C per day; fall: 16-24°C, winter: 12-20°C, summer: 20-28°C and kept at elevated temperature for 3 weeks. Healthy mussels experienced thermal stress and entered the time-limited survival period in the fall, became acclimated in winter and exhibited sublethal damage in summer. In stressed mussels, thermal stress and subsequent health deterioration were elicited in the fall but no transition into the critical period of time-limited survival was observed. Stressed mussels did not become acclimated to 20°C in winter, when they experienced low-to-moderate thermal stress, and did not experience sublethal damage at 28°C in summer, showing instead signs of metabolic rate depression. Overall, although the thermal threshold was lowered in chronically stressed mussels, they exhibited enhanced tolerance to seasonal gradual warming, especially in summer. These results challenge current assumptions on the susceptibility of marine biota to the interactive effects of seawater warming and pollution.

  12. On the shortening of Indian summer monsoon season in a warming scenario

    Science.gov (United States)

    Sabeerali, C. T.; Ajayamohan, R. S.

    2018-03-01

    Assessing the future projections of the length of rainy season (LRS) has paramount societal impact considering its potential to alter the seasonal mean rainfall over the Indian subcontinent. Here, we explored the projections of LRS using both historical and Representative Concentration Pathways 8.5 (RCP8.5) simulations of the Coupled Model Intercomparison Project Phase5 (CMIP5). RCP8.5 simulations project shortening of the LRS of Indian summer monsoon by altering the timing of onset and withdrawal dates. Most CMIP5 RCP8.5 model simulations indicate a faster warming rate over the western tropical Indian Ocean compared to other regions of the Indian Ocean. It is found that the pronounced western Indian Ocean warming and associated increase in convection results in warmer upper troposphere over the Indian Ocean compared to the Indian subcontinent, reducing the meridional gradient in upper tropospheric temperature (UTT) over the Asian summer monsoon (ASM) domain. The weakening of the meridional gradient in UTT induces weakening of easterly vertical wind shear over the ASM domain during first and last phase of monsoon, facilitate delayed (advanced) monsoon onset (withdrawal) dates, ensues the shortening of LRS of the Indian summer monsoon in a warming scenario.

  13. Grassland bird productivity in warm season grass fields in southwest Wisconsin

    Science.gov (United States)

    Byers, Carolyn M.; Ribic, Christine; Sample, David W.; Dadisman, John D.; Guttery, Michael

    2017-01-01

    Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agriculture's Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Grasshopper Sparrow (Ammodramus savannarum), and Henslow's Sparrow (A. henslowii), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslow's Sparrow nest density was highest 1 y post burn, and apparent Bobolink and Eastern Meadowlark nest densities were higher in post fire years one to three. Grasshopper Sparrow nest density was highest on sites with more diverse vegetation, specifically prairie forbs, and on sites with shorter less dense vegetation. Bobolink, Eastern Meadowlark, and Henslow's Sparrow apparent nest densities were higher on sites with deeper litter; litter was the vegetative component that was most affected by spring burns. Overall nest success was 0.487 for Bobolink (22 d nesting period), 0.478 for Eastern Meadowlark (25 d nesting period), 0.507 for Grasshopper Sparrow (22 d nesting period), and 0.151 for Henslow's Sparrow (21 d nesting period). The major nest predators were grassland-associated species: thirteen-lined ground squirrel (Ictidomys tridecemlineatus), striped skunk (Mephitis mephitis), milk snake (Lampropeltis triangulum), American badger (Taxidea taxus), and western fox snake (Elaphe vulpina). Overall

  14. Seasonal/Interannual Variations of Carbon Sequestration and Carbon Emission in a Warm-Season Perennial Grassland

    OpenAIRE

    Deepa Dhital; Tomoharu Inoue; Hiroshi Koizumi

    2014-01-01

    Carbon sequestration and carbon emission are processes of ecosystem carbon cycling that can be affected while land area converted to grassland resulting in increased soil carbon storage and below-ground respiration. Discerning the importance of carbon cycle in grassland, we aimed to estimate carbon sequestration in photosynthesis and carbon emission in respiration from soil, root, and microbes, for four consecutive years (2007–2010) in a warm-season perennial grassland, Japan. Soil carbon emi...

  15. Seasonal Variation in Mortality, Medical Care Expenditure and Institutionalization in Older People

    DEFF Research Database (Denmark)

    Rolden, Herbert Jan Albert; Rohling, Jos Hermanus Theodoor; van Bodegom, David

    2015-01-01

    . It is therefore important to investigate the impact of the seasons on MCE both mediated and unmediated by mortality. METHODS: Data on mortality, MCE and institutionalization from people aged 65 and older in a region in the Netherlands from July 2007 through 2010 were retrieved from a regional health care insurer...... in mortality is similar for both institutionalized and community-dwelling elderly. Policy-makers, epidemiologists and health economists are urged to acknowledge and include the impact of the seasons in future policy and research....

  16. Nitrogen Fertilization Effect on Phosphorus Remediation Potential of Three Perennial Warm-Season Forages

    NARCIS (Netherlands)

    Newman, Y.C.; Agyin-Birikorang, S.; Adjei, M.B.; Scholberg, J.M.S.; Silveira, M.L.; Vendramini, J.M.B.; Rechcigl, J.E.; Sollenberger, L.E.

    2009-01-01

    Warm-season C-4 grasses are capable of removing excess soil nutrients because of their high Yield potential and nutrient uptake efficiency. Bahiagrass (Paspalum notatum Flugge), limpograss [Hemarthria altissima (Poir.) Stapf& Hubb], and stargrass (Cynodon nlemfuensis Vanderyst), three commonly

  17. Positive feedback of greenhouse gas balances to warming is determined by non-growing season emissions in an alpine meadow

    Science.gov (United States)

    Niu, S.; Wang, J.; Quan, Q.; Chen, W.; Wen, X.; Yu, G.

    2017-12-01

    Large uncertainties exist in the sources and sinks of greenhouse gases (CO2, CH4, N2O) in response to climate warming and human activity. So far, numerous previous studies have evaluated the CO2 budget, but little attention has paid to CH4 and N2O budgets and the concurrent balance of these three gases in combination, especially in the non-growing season. Here, we synthesized eddy covariance measurement with the automatic chamber measurements of CO2, CH4, and N2O exposed to three levels of temperature treatments (ambient, +1.5 °C, +2.5 °C) and two disturbance treatments (ummowing, mowing) in an alpine meadow on the Tibetan Plateau. We have found that warming caused increase in CH4 uptake and decrease in N2O emission offset little of the enhancement in CO2 emission, triggering a positive feedback to climate warming. Warming switches the ecosystem from a net sink (-17 ± 14 g CO2-eq m-2 yr-1) in the control to a net source of greenhouse gases of 94 ± 36 gCO2-eq m-2 yr-1 in the plots with +1.5 °C warming treatment, and 177 ± 6 gCO2-eq m-2 yr-1 in the plots with +2.5 °C warming treatment. The changes in the non-growing season balance, rather than those in the growing season, dominate the warming responses of annual greehouse gas balance. And this is not changed by mowing. The dominant role of responses of winter greenhouse gas balance in the positive feedback of ecosystem to climate warming highlights that greenhouse gas balance in cold season has to be considered when assessing climate-carbon cycle feedback.

  18. Did medieval trade activity and a viral etiology control the spatial extent and seasonal distribution of Black Death mortality?

    Science.gov (United States)

    Bossak, Brian H; Welford, Mark R

    2009-06-01

    Recent research into the world's greatest recorded epidemic, the Medieval Black Death (MBD), has cast doubt on Bubonic Plague as the etiologic agent. Prior research has recently culminated in outstanding advances in our understanding of the spatio-temporal pattern of MBD mortality, and a characterization of the incubation, latent, infectious, and symptomatic periods of the MBD. However, until now, several mysteries remained unexplained, including perhaps the biggest quandary of all: why did the MBD exhibit inverse seasonal peaks in mortality from diseases recorded in modern times, such as seasonal Influenza or the Indian Plague Epidemics of the early 1900 s? Although some have argued that climate changes likely explain the observed differences between modern clinical Bubonic Plague seasonality and MBD mortality accounts, we believe that another factor explains these dissimilarities. Here, we provide a synthetic hypothesis which builds upon previous theories developed in the last ten years or so. Our all-encompassing theory explains the causation, dissemination, and lethality of the MBD. We theorize that the MBD was a human-to-human transmitted virus, originating in East-Central Asia and not Africa (as some recent work has proposed), and that its areal extent during the first great epidemic wave of 1347-1350 was controlled hierarchically by proximity to trade routes. We also propose that the seasonality of medieval trade controlled the warm-weather mortality peaks witnessed during 1347-1350; during the time of greatest market activity, traders, fairgoers, and religious pilgrims served as unintentional vectors of a lethal virus with an incubation period of approximately 32 days, including a largely asymptomatic yet infectious period of roughly three weeks. We include a description of the rigorous research agenda that we have proposed in order to subject our theory to scientific scrutiny and a description of our plans to generate the first publicly available

  19. Observed decreases in the Canadian outdoor skating season due to recent winter warming

    International Nuclear Information System (INIS)

    Damyanov, Nikolay N; Mysak, Lawrence A; Damon Matthews, H

    2012-01-01

    Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada. (letter)

  20. Observed decreases in the Canadian outdoor skating season due to recent winter warming

    Science.gov (United States)

    Damyanov, Nikolay N.; Damon Matthews, H.; Mysak, Lawrence A.

    2012-03-01

    Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada.

  1. European seasonal mortality and influenza incidence due to winter temperature variability

    Science.gov (United States)

    Rodó, X.; Ballester, J.; Robine, J. M.; Herrmann, F. R.

    2017-12-01

    Recent studies have vividly emphasized the lack of consensus on the degree of vulnerability (sensu IPCC) of European societies to current and future winter temperatures. Here we consider several climate factors, influenza incidence and daily numbers of deaths to characterize the relationship between winter temperature and mortality in a very large ensemble of European regions representing more than 400 million people. Analyses highlight the strong association between the year-to-year fluctuations in winter mean temperature and mortality, with higher seasonal cases during harsh winters, in all of the countries except the United Kingdom, the Netherlands and Belgium. This spatial distribution contrasts with the well-documented latitudinal orientation of the dependency between daily temperature and mortality within the season. A theoretical framework is proposed to reconcile the apparent contradictions between recent studies, offering an interpretation to regional differences in the vulnerability to daily, seasonal and long-term winter temperature variability. Despite the lack of a strong year-to-year association between winter mean values in some countries, it can be concluded that warmer winters will contribute to the decrease in winter mortality everywhere in Europe. More information in Ballester J, et al. (2016) Nature Climate Change 6, 927-930, doi:10.1038/NCLIMATE3070.

  2. Annual warm-season grasses vary for forage yield, quality, and competitiveness with weeds

    Science.gov (United States)

    Warm-season annual grasses may be suitable as herbicide-free forage crops. A two-year field study was conducted to determine whether tillage system and nitrogen (N) fertilizer application method influenced crop and weed biomass, water use, water use efficiency (WUE), and forage quality of three war...

  3. Observed changes in seasonal heat waves and warm temperature extremes in the Romanian Carpathians

    Science.gov (United States)

    Micu, Dana; Birsan, Marius-Victor; Dumitrescu, Alexandru; Cheval, Sorin

    2015-04-01

    Extreme high temperature have a large impact on environment and human activities, especially in high elevation areas particularly sensitive to the recent climate warming. The climate of the Romanian Carpathians became warmer particularly in winter, spring and summer, exibiting a significant increasing frequency of warm extremes. The paper investigates the seasonal changes in the frequency, duration and intensity of heat waves in relation to the shifts in the daily distribution of maximum temperatures over a 50-year period of meteorological observations (1961-2010). The paper uses the heat wave definition recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) and exploits the gridded daily dataset of maximum temperature at 0.1° resolution (~10 km) developed in the framework of the CarpatClim project (www.carpatclim.eu). The seasonal changes in heat waves behavior were identified using the Mann-Kendall non-parametric trend test. The results suggest an increase in heat wave frequency and a lengthening of intervals affected by warm temperature extremes all over the study region, which are explained by the shifts in the upper (extreme) tail of the daily maximum temperature distribution in most seasons. The trends are consistent across the region and are well correlated to the positive phases of the East Atlantic Oscillation. Our results are in good agreement with the previous temperature-related studies concerning the Carpathian region. This study was realized within the framework of the project GENCLIM, financed by UEFISCDI, code PN-II 151/2014.

  4. The risk mortality of the population of azerbaijan from circulatory diseases, depending on the season

    Directory of Open Access Journals (Sweden)

    A. J. Rzayeva

    2015-06-01

    Azerbaijan State Advanced Training Institute for doctors named after A. Aliyev, Baku   ABSTRACT The Objective.  To obtain evidence-based data about the role of seasons of the year in the formation of the population mortality risk from the circulatory system diseases  (CSD in Azerbaijan and its regions with specific climate. Materials of the study. A case of mortality was a unit of statistical observation. The fatalities from all reasons, including CSD have been distributed by the days of every month in the year. Daily average amount of fatalities by months and seasons ( from 20 December to 19 March – winter; from 20 March to 19 June- spring; from 20 June to 16 September; from 20 September to 19 December - autumn have been determined. Results.  In Azerbaijan the risk of general mortality and mortality from CSD is the highest in winter, it decreases in spring but nonuniformly (the general mortality rate is less than that from CSD. That is why the share of CSD increases among mortality reasons. Conclusions. Seasonal change of mortality risks from CSD is multivariant. Winter-spring increase of risk predominates in Azerbaijan. In some regions of Azerbaijan the mortality risk from CSD increases only once either in spring or in summer or winter. Key words: seasonal dynamics, risk of mortality, circulatory system diseases.

  5. Magnitude and pattern of Arctic warming governed by the seasonality of radiative forcing.

    Science.gov (United States)

    Bintanja, R; Krikken, F

    2016-12-02

    Observed and projected climate warming is strongest in the Arctic regions, peaking in autumn/winter. Attempts to explain this feature have focused primarily on identifying the associated climate feedbacks, particularly the ice-albedo and lapse-rate feedbacks. Here we use a state-of-the-art global climate model in idealized seasonal forcing simulations to show that Arctic warming (especially in winter) and sea ice decline are particularly sensitive to radiative forcing in spring, during which the energy is effectively 'absorbed' by the ocean (through sea ice melt and ocean warming, amplified by the ice-albedo feedback) and consequently released to the lower atmosphere in autumn and winter, mainly along the sea ice periphery. In contrast, winter radiative forcing causes a more uniform response centered over the Arctic Ocean. This finding suggests that intermodel differences in simulated Arctic (winter) warming can to a considerable degree be attributed to model uncertainties in Arctic radiative fluxes, which peak in summer.

  6. Seasonal body size reductions with warming covary with major body size gradients in arthropod species

    DEFF Research Database (Denmark)

    Horne, Curtis R.; Hirst, Andrew G.; Atkinson, David

    2017-01-01

    experience different developmental conditions. Yet, unlike other size patterns, these common seasonal temperature–size gradients have never been collectively analysed. We undertake the largest analysis to date of seasonal temperature-size gradients in multivoltine arthropods, including 102 aquatic...... and terrestrial species from 71 global locations. Adult size declines in warmer seasons in 86% of the species examined. Aquatic species show approximately 2.5-fold greater reduction in size per °C of warming than terrestrial species, supporting the hypothesis that greater oxygen limitation in water than in air...

  7. Incorporating residual temperature and specific humidity in predicting weather-dependent warm-season electricity consumption

    Science.gov (United States)

    Guan, Huade; Beecham, Simon; Xu, Hanqiu; Ingleton, Greg

    2017-02-01

    Climate warming and increasing variability challenges the electricity supply in warm seasons. A good quantitative representation of the relationship between warm-season electricity consumption and weather condition provides necessary information for long-term electricity planning and short-term electricity management. In this study, an extended version of cooling degree days (ECDD) is proposed for better characterisation of this relationship. The ECDD includes temperature, residual temperature and specific humidity effects. The residual temperature is introduced for the first time to reflect the building thermal inertia effect on electricity consumption. The study is based on the electricity consumption data of four multiple-street city blocks and three office buildings. It is found that the residual temperature effect is about 20% of the current-day temperature effect at the block scale, and increases with a large variation at the building scale. Investigation of this residual temperature effect provides insight to the influence of building designs and structures on electricity consumption. The specific humidity effect appears to be more important at the building scale than at the block scale. A building with high energy performance does not necessarily have low specific humidity dependence. The new ECDD better reflects the weather dependence of electricity consumption than the conventional CDD method.

  8. Seasonal variations in methane fluxes in response to summer warming and leaf litter addition in a subarctic heath ecosystem

    Science.gov (United States)

    Pedersen, Emily Pickering; Elberling, Bo; Michelsen, Anders

    2017-08-01

    Methane (CH4) is a powerful greenhouse gas controlled by both biotic and abiotic processes. Few studies have investigated CH4 fluxes in subarctic heath ecosystems, and climate change-induced shifts in CH4 flux and the overall carbon budget are therefore largely unknown. Hence, there is an urgent need for long-term in situ experiments allowing for the study of ecosystem processes over time scales relevant to environmental change. Here we present in situ CH4 and CO2 flux measurements from a wet heath ecosystem in northern Sweden subjected to 16 years of manipulations, including summer warming with open-top chambers, birch leaf litter addition, and the combination thereof. Throughout the snow-free season, the ecosystem was a net sink of CH4 and CO2 (CH4 -0.27 mg C m-2 d-1; net ecosystem exchange -1827 mg C m-2 d-1), with highest CH4 uptake rates (-0.70 mg C m-2 d-1) during fall. Warming enhanced net CO2 flux, while net CH4 flux was governed by soil moisture. Litter addition and the combination with warming significantly increased CH4 uptake rates, explained by a pronounced soil drying effect of up to 32% relative to ambient conditions. Both warming and litter addition also increased the seasonal average concentration of dissolved organic carbon in the soil. The site was a carbon sink with a net uptake of 60 g C m-2 over the snow-free season. However, warming reduced net carbon uptake by 77%, suggesting that this ecosystem type might shift from snow-free season sink to source with increasing summer temperatures.

  9. Seasonal analysis of the short-term effects of air pollution on daily mortality in Northeast Asia.

    Science.gov (United States)

    Kim, Satbyul Estella; Honda, Yasushi; Hashizume, Masahiro; Kan, Haidong; Lim, Youn-Hee; Lee, Hyewon; Kim, Clara Tammy; Yi, Seung-Muk; Kim, Ho

    2017-01-15

    The constituents and concentrations of pollutants, individual exposures, and biologic responses to air pollution may vary by season and meteorological conditions. However, evidence regarding seasonality of the acute effects of air pollution on mortality is limited and inconsistent. Herein, we examined seasonal patterns in the short-term associations of particulate matter (PM) smaller than 10μm (PM 10 ) with daily mortality in 29 cities of three northeast Asian countries. Stratified time-series models were used to determine whether season altered the effect of PM 10 on mortality. This effect was first quantified within each season and at each location using a time-series model, after which city-specific estimates were pooled using a hierarchical Bayesian model. In all data sets, 3,675,348 non-accidental deaths were registered from 1993 to 2009. In Japan, a 10μg/m 3 increase in PM 10 was significantly associated with increases in non-accidental mortality of 0.44% (95% confidence interval [CI]: 0.03%, 0.8%) in spring and 0.42% (0.02%, 0.82%) in fall. In South Korea, a 10μg/m 3 increase in PM 10 was significantly associated with increases in non-accidental mortality of 0.51% (0.01%, 1.01%) in summer and 0.45% (0.03%, 0.87%) in fall, in cardiovascular disease mortality of 0.96% (0.29%, 1.63%) in fall, and in respiratory disease mortality of 1.57% (0.40%, 2.75%) in fall. In China, a 10μg/m 3 increase in PM 10 was associated with increases in non-accidental mortality of 0.33% (0.01%, 0.66%) in summer and 0.41% (0.09%, 0.73%) in winter, in cardiovascular disease mortality of 0.41% (0.08%, 0.74%) in spring and 0.33% (0.02%, 0.64%) in winter, and in respiratory diseases mortality of 0.78% (0.27%, 1.30%) in winter. Our analyses suggest that the acute effect of particulate air pollution could vary seasonally and geographically. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Disruption of the European climate seasonal clock in a warming world

    Science.gov (United States)

    Cattiaux, J.; Cassou, C.

    2015-12-01

    Strength and inland penetration of the oceanic westerly flow over Europe control a large part of the temperature variability over most of the continent. Reduced westerlies, linked to high-pressure anomalies over Scandinavia, induce cold conditions in winter and warm conditions in summer. Here we propose to define the onset of these two seasons as the calendar day where the daily circulation/temperature relationship over Western Europe switches sign. According to this meteorologically-based metrics assessed from several observational datasets, we provide robust evidence for an earlier summer onset by ~10 days between the 1960s and 2000s. Results from model ensemble simulations dedicated to detection-attribution show that this calendar advance is incompatible with the sole internal climate variability and can be attributed to anthropogenic forcings. Late winter snow disappearance over Eastern Europe affects cold air intrusion to the West when easterlies blow, and is mainly responsible for the observed present-day and near-future summer advance. Our findings agree with phenological-based trends (earlier spring events) reported for many living species over Europe, for which they provide a novel dynamical interpretation beyond the traditionally evoked global warming effect. Based on business-as-usual scenario, a seasonal shift of ~25 days is expected by 2100 for summer onset, while no clear signal arises for winter onset.

  11. Risk of Cardiovascular Morbidity and Mortality in Relation to Temperature

    Science.gov (United States)

    Mathes, Robert; Ito, Kazuhiko; Matte, Thomas

    2013-01-01

    Objective To examine the effects of temperature on cardiovascular-related (CVD) morbidity and mortality among New York City (NYC) residents. Introduction Extreme temperatures are consistently shown to have an effect on CVD-related mortality [1, 2]. A large multi-city study of mortality demonstrated a cold-day and hot-day weather effect on CVD-related deaths, with the larger impact occurring on the coldest days [3]. In contrast, the association between weather and CVD-related morbidity is less clear [4, 5]. The purpose of this study is to characterize the effect of temperature on CVD-related emergency department (ED) visits, hospitalizations, and mortality on a large, heterogeneous population. Additionally, we conducted a sensitivity analysis to determine the impact of air pollutants, specifically fine particulates (PM2.5) and ozone (O3), along with temperature, on CVD outcomes. Methods We analyzed daily weather conditions, ED visits classified as CVD-related based on chief complaint text, hospitalizations, and natural cause deaths that occurred in NYC between 2002 and 2006. ED visits were obtained from data reported daily to the city health department for syndromic surveillance. Inpatient admissions were obtained from the Statewide Planning and Research Cooperative System, a data reporting system developed by New York State. Mortality data were obtained from the NYC Office of Vital Statistics. Data for PM2.5 and O3 were obtained from all available air quality monitors within the five boroughs of NYC. To estimate risk of CVD morbidity and mortality, we used generalized linear models using a Poisson distribution to calculate relative risks (RR) and 95% confidence intervals (CI). A non-linear distributed lag was used to model mean temperature in order to allow for its effect on the same day and on subsequent days. Models were fit separately for cold season (October through March) and warm season (April through September) given season may modify the effect on CVD

  12. An Update to the Warm-Season Convective Wind Climatology of KSC/CCAFS

    Science.gov (United States)

    Lupo, Kevin

    2012-01-01

    Total of 1100 convective events in the 17-year warm-season climatology at KSC/CCAFS. July and August typically are the peak of convective events, May being the minimum. Warning and non-warning level convective winds are more likely to occur in the late afternoon (1900-2000Z). Southwesterly flow regimes and wind directions produce the strongest winds. Storms moving from southwesterly direction tend to produce more warning level winds than those moving from the northerly and easterly directions.

  13. Lagged effect of diurnal temperature range on mortality in a subtropical megacity of China.

    Directory of Open Access Journals (Sweden)

    Yuan Luo

    Full Text Available BACKGROUND: Many studies have found extreme temperature can increase the risk of mortality. However, it is not clear whether extreme diurnal temperature range (DTR is associated with daily disease-specific mortality, and how season might modify any association. OBJECTIVES: To better understand the acute effect of DTR on mortality and identify whether season is a modifier of the DTR effect. METHODS: The distributed lag nonlinear model (DLNM was applied to assess the non-linear and delayed effects of DTR on deaths (non-accidental mortality (NAD, cardiovascular disease (CVD, respiratory disease (RD and cerebrovascular disease (CBD in the full year, the cold season and the warm season. RESULTS: A non-linear relationship was consistently found between extreme DTR and mortality. Immediate effects of extreme low DTR on all types of mortality were stronger than those of extreme high DTR in the full year. The cumulative effects of extreme DTRs increased with the increment of lag days for all types of mortality in cold season, and they were greater for extreme high DTRs than those of extreme low DTRs. In hot season, the cumulative effects for extreme low DTRs increased with the increment of lag days, but for extreme high DTR they reached maxima at a lag of 13 days for all types of mortality except for CBD(at lag6 days, and then decreased. CONCLUSIONS: Our findings suggest that extreme DTR is an independent risk factor of daily mortality, and season is a modifier of the association of DTR with daily mortality.

  14. Excess winter mortality and cold temperatures in a subtropical city, Guangzhou, China.

    Directory of Open Access Journals (Sweden)

    Chun-Quan Ou

    Full Text Available BACKGROUND: A significant increase in mortality was observed during cold winters in many temperate regions. However, there is a lack of evidence from tropical and subtropical regions, and the influence of ambient temperatures on seasonal variation of mortality was not well documented. METHODS: This study included 213,737 registered deaths from January 2003 to December 2011 in Guangzhou, a subtropical city in Southern China. Excess winter mortality was calculated by the excess percentage of monthly mortality in winters over that of non-winter months. A generalized linear model with a quasi-Poisson distribution was applied to analyze the association between monthly mean temperature and mortality, after controlling for other meteorological measures and air pollution. RESULTS: The mortality rate in the winter was 26% higher than the average rate in other seasons. On average, there were 1,848 excess winter deaths annually, with around half (52% from cardiovascular diseases and a quarter (24% from respiratory diseases. Excess winter mortality was higher in the elderly, females and those with low education level than the young, males and those with high education level, respectively. A much larger winter increase was observed in out-of-hospital mortality compared to in-hospital mortality (45% vs. 17%. We found a significant negative correlation of annual excess winter mortality with average winter temperature (rs=-0.738, P=0.037, but not with air pollution levels. A 1 °C decrease in monthly mean temperature was associated with an increase of 1.38% (95% CI:0.34%-2.40% and 0.88% (95% CI:0.11%-1.64% in monthly mortality at lags of 0-1 month, respectively. CONCLUSION: Similar to temperate regions, a subtropical city Guangzhou showed a clear seasonal pattern in mortality, with a sharper spike in winter. Our results highlight the role of cold temperature on the winter mortality even in warm climate. Precautionary measures should be strengthened to mitigate

  15. Rapid warming accelerates tree growth decline in semi-arid forests of Inner Asia.

    Science.gov (United States)

    Liu, Hongyan; Park Williams, A; Allen, Craig D; Guo, Dali; Wu, Xiuchen; Anenkhonov, Oleg A; Liang, Eryuan; Sandanov, Denis V; Yin, Yi; Qi, Zhaohuan; Badmaeva, Natalya K

    2013-08-01

    Forests around the world are subject to risk of high rates of tree growth decline and increased tree mortality from combinations of climate warming and drought, notably in semi-arid settings. Here, we assess how climate warming has affected tree growth in one of the world's most extensive zones of semi-arid forests, in Inner Asia, a region where lack of data limits our understanding of how climate change may impact forests. We show that pervasive tree growth declines since 1994 in Inner Asia have been confined to semi-arid forests, where growing season water stress has been rising due to warming-induced increases in atmospheric moisture demand. A causal link between increasing drought and declining growth at semi-arid sites is corroborated by correlation analyses comparing annual climate data to records of tree-ring widths. These ring-width records tend to be substantially more sensitive to drought variability at semi-arid sites than at semi-humid sites. Fire occurrence and insect/pathogen attacks have increased in tandem with the most recent (2007-2009) documented episode of tree mortality. If warming in Inner Asia continues, further increases in forest stress and tree mortality could be expected, potentially driving the eventual regional loss of current semi-arid forests. © 2013 John Wiley & Sons Ltd.

  16. Global warming related transient albedo feedback in the Arctic and its relation to the seasonality of sea ice

    Science.gov (United States)

    Andry, Olivier; Bintanja, Richard; Hazeleger, Wilco

    2015-04-01

    The Arctic is warming two to three times faster than the global average. Arctic sea ice cover is very sensitive to this warming and has reached historic minima in late summer in recent years (i.e. 2007, 2012). Considering that the Arctic Ocean is mainly ice-covered and that the albedo of sea ice is very high compared to that of open water, the change in sea ice cover is very likely to have a strong impact on the local surface albedo feedback. Here we quantify the temporal changes in surface albedo feedback in response to global warming. Usually feedbacks are evaluated as being representative and constant for long time periods, but we show here that the strength of climate feedbacks in fact varies strongly with time. For instance, time series of the amplitude of the surface albedo feedback, derived from future climate simulations (CIMP5, RCP8.5 up to year 2300) using a kernel method, peaks around the year 2100. This maximum is likely caused by an increased seasonality in sea-ice cover that is inherently associated with sea ice retreat. We demonstrate that the Arctic average surface albedo has a strong seasonal signature with a maximum in spring and a minimum in late summer/autumn. In winter when incoming solar radiation is minimal the surface albedo doesn't have an important effect on the energy balance of the climate system. The annual mean surface albedo is thus determined by the seasonality of both downwelling shortwave radiation and sea ice cover. As sea ice cover reduces the seasonal signature is modified, the transient part from maximum sea ice cover to its minimum is shortened and sharpened. The sea ice cover is reduced when downwelling shortwave radiation is maximum and thus the annual surface albedo is drastically smaller. Consequently the change in annual surface albedo with time will become larger and so will the surface albedo feedback. We conclude that a stronger seasonality in sea ice leads to a stronger surface albedo feedback, which accelerates

  17. Projected warming portends seasonal shifts of stream temperatures in the Crown of the Continent Ecosystem, USA and Canada

    Science.gov (United States)

    Jones, Leslie A.; Muhlfeld, Clint C.; Marshall, Lucy A.

    2017-01-01

    Climate warming is expected to increase stream temperatures in mountainous regions of western North America, yet the degree to which future climate change may influence seasonal patterns of stream temperature is uncertain. In this study, a spatially explicit statistical model framework was integrated with empirical stream temperature data (approximately four million bi-hourly recordings) and high-resolution climate and land surface data to estimate monthly stream temperatures and potential change under future climate scenarios in the Crown of the Continent Ecosystem, USA and Canada (72,000 km2). Moderate and extreme warming scenarios forecast increasing stream temperatures during spring, summer, and fall, with the largest increases predicted during summer (July, August, and September). Additionally, thermal regimes characteristic of current August temperatures, the warmest month of the year, may be exceeded during July and September, suggesting an earlier and extended duration of warm summer stream temperatures. Models estimate that the largest magnitude of temperature warming relative to current conditions may be observed during the shoulder months of winter (April and November). Summer stream temperature warming is likely to be most pronounced in glacial-fed streams where models predict the largest magnitude (> 50%) of change due to the loss of alpine glaciers. We provide the first broad-scale analysis of seasonal climate effects on spatiotemporal patterns of stream temperature in the Crown of the Continent Ecosystem for better understanding climate change impacts on freshwater habitats and guiding conservation and climate adaptation strategies.

  18. Seasonal variation in short-term mortality after surgery for colorectal cancer?

    DEFF Research Database (Denmark)

    Iversen, L H; Nielsen, H; Pedersen, L

    2010-01-01

    Comorbidity has a major impact on short-term and long-term survival of colorectal cancer (CRC) and many CRC patients suffer from comorbidities. Mortality rates for comorbidities like cardio-respiratory diseases exhibit distinct seasonal variations with highest rates in the winter. Therefore, we...

  19. Latitudinal variation in seasonal activity and mortality in ratsnakes (Elaphe obsoleta).

    Science.gov (United States)

    Sperry, Jinelle H; Blouin-Demers, Gabriel; Carfagno, Gerardo L F; Weatherhead, Patrick J

    2010-06-01

    The ecology of ectotherms should be particularly affected by latitude because so much of their biology is temperature dependent. Current latitudinal patterns should also be informative about how ectotherms will have to modify their behavior in response to climate change. We used data from a total of 175 adult black ratsnakes (Elaphe obsoleta) radio-tracked in Ontario, Illinois, and Texas, a latitudinal distance of >1500 km, to test predictions about how seasonal patterns of activity and mortality should vary with latitude. Despite pronounced differences in temperatures among study locations, and despite ratsnakes in Texas not hibernating and switching from diurnal to nocturnal activity in the summer, seasonal patterns of snake activity were remarkably similar during the months that snakes in all populations were active. Rather than being a function of temperature, activity may be driven by the timing of reproduction, which appears similar among populations. Contrary to the prediction that mortality should be highest in the most active population, overall mortality did not follow a clinal pattern. Winter mortality did increase with latitude, however, consistent with temperature limiting the northern distribution of ratsnakes. This result was opposite that found in the only previous study of latitudinal variation in winter mortality in reptiles, which may be a consequence of whether or not the animals exhibit true hibernation. Collectively, these results suggest that, at least in the northern part of their range, ratsnakes should be able to adjust easily to, and may benefit from, a warmer climate, although climate-based changes to the snakes' prey or habitat, for example, could alter that prediction.

  20. INTERACTIONS BETWEEN OCEAN ACIDIFICATION AND WARMING ON THE MORTALITY AND DISSOLUTION OF CORALLINE ALGAE(1).

    Science.gov (United States)

    Diaz-Pulido, Guillermo; Anthony, Kenneth R N; Kline, David I; Dove, Sophie; Hoegh-Guldberg, Ove

    2012-02-01

    Coralline algae are among the most sensitive calcifying organisms to ocean acidification as a result of increased atmospheric carbon dioxide (pCO2 ). Little is known, however, about the combined impacts of increased pCO2 , ocean acidification, and sea surface temperature on tissue mortality and skeletal dissolution of coralline algae. To address this issue, we conducted factorial manipulative experiments of elevated CO2 and temperature and examined the consequences on tissue survival and skeletal dissolution of the crustose coralline alga (CCA) Porolithon (=Hydrolithon) onkodes (Heydr.) Foslie (Corallinaceae, Rhodophyta) on the southern Great Barrier Reef (GBR), Australia. We observed that warming amplified the negative effects of high pCO2 on the health of the algae: rates of advanced partial mortality of CCA increased from warming conditions (from 26°C to 29°C). Furthermore, the effect of pCO2 on skeletal dissolution strongly depended on temperature. Dissolution of P. onkodes only occurred in the high-pCO2 treatment and was greater in the warm treatment. Enhanced skeletal dissolution was also associated with a significant increase in the abundance of endolithic algae. Our results demonstrate that P. onkodes is particularly sensitive to ocean acidification under warm conditions, suggesting that previous experiments focused on ocean acidification alone have underestimated the impact of future conditions on coralline algae. Given the central role that coralline algae play within coral reefs, these conclusions have serious ramifications for the integrity of coral-reef ecosystems. © 2011 Phycological Society of America.

  1. The effects of season and meteorology on human mortality in tropical climates: a systematic review.

    Science.gov (United States)

    Burkart, Katrin; Khan, Md Mobarak Hossain; Schneider, Alexandra; Breitner, Susanne; Langner, Marcel; Krämer, Alexander; Endlicher, Wilfried

    2014-07-01

    Research in the field of atmospheric science and epidemiology has long recognized the health effects of seasonal and meteorological conditions. However, little scientific knowledge exists to date about the impacts of atmospheric parameters on human mortality in tropical regions. Working within the scope of this systematic review, this investigation conducted a literature search using different databases; original research articles were chosen according to pre-defined inclusion and exclusion criteria. Both seasonal and meteorological effects were considered. The findings suggest that high amounts of rainfall and increasing temperatures cause a seasonal excess in infectious disease mortality and are therefore relevant in regions and populations in which such diseases are prevalent. On the contrary, moderately low and very high temperatures exercise an adverse effect on cardio-respiratory mortality and shape the mortality pattern in areas and sub-groups in which these diseases are dominant. Atmospheric effects were subject to population-specific factors such as age and socio-economic status and differed between urban and rural areas. The consequences of climate change as well as environmental, epidemiological and social change (e.g., emerging non-communicable diseases, ageing of the population, urbanization) suggest a growing relevance of heat-related excess mortality in tropical regions. © The Author 2014. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    Science.gov (United States)

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). © 2015 John Wiley & Sons Ltd.

  3. Case-based reported mortality associated with laboratory-confirmed influenza A(H1N1 2009 virus infection in the Netherlands: the 2009-2010 pandemic season versus the 2010-2011 influenza season

    Directory of Open Access Journals (Sweden)

    Timen Aura

    2011-10-01

    Full Text Available Abstract Background In contrast to seasonal influenza epidemics, where the majority of deaths occur amongst elderly, a considerable part of the 2009 pandemic influenza related deaths concerned relatively young people. In the Netherlands, all deaths associated with laboratory-confirmed influenza A(H1N1 2009 virus infection had to be notified, both during the 2009-2010 pandemic season and the 2010-2011 influenza season. To assess whether and to what extent pandemic mortality patterns were reverting back to seasonal patterns, a retrospective analyses of all notified fatal cases associated with laboratory-confirmed influenza A(H1N1 2009 virus infection was performed. Methods The notification database, including detailed information about the clinical characteristics of all notified deaths, was used to perform a comprehensive analysis of all deceased patients with a laboratory-confirmed influenza A(H1N1 2009 virus infection. Characteristics of the fatalities with respect to age and underlying medical conditions were analysed, comparing the 2009-2010 pandemic and the 2010-2011 influenza season. Results A total of 65 fatalities with a laboratory-confirmed influenza A(H1N1 2009 virus infection were notified in 2009-2010 and 38 in 2010-2011. During the pandemic season, the population mortality rates peaked in persons aged 0-15 and 55-64 years. In the 2010-2011 influenza season, peaks in mortality were seen in persons aged 0-15 and 75-84 years. During the 2010-2011 influenza season, the height of first peak was lower compared to that during the pandemic season. Underlying immunological disorders were more common in the pandemic season compared to the 2010-2011 season (p = 0.02, and cardiovascular disorders were more common in the 2010-2011 season (p = 0.005. Conclusions The mortality pattern in the 2010-2011 influenza season still resembled the 2009-2010 pandemic season with a peak in relatively young age groups, but concurrently a clear shift toward

  4. The effects of dust–haze on mortality are modified by seasons and individual characteristics in Guangzhou, China

    International Nuclear Information System (INIS)

    Liu, Tao; Zhang, Yong Hui; Xu, Yan Jun; Lin, Hua Liang; Xu, Xiao Jun; Luo, Yuan; Xiao, JianPeng; Zeng, Wei Lin; Zhang, Wan Fang; Chu, Cordia; Keogh, Kandice; Rutherford, Shannon; Qian, Zhengmin; Du, Yao Dong

    2014-01-01

    This study aimed to investigate the effects of dust–haze on mortality and to estimate the seasonal and individual-specific modification effects in Guangzhou, China. Mortality, air pollution and meteorological data were collected for 2006–2011. A dust–haze day was defined as daily visibility 10 . We concluded that dust–haze significantly increased mortality risk in Guangzhou, China, and this effect appears to be dominated by particulate mass and modified by season and individual-specific factors. - Highlights: • We assessed the health impact of dust–haze in a megacity of southern China. • A dust–haze was defined according to visibility and relative humidity. • Dust–haze increased mortality risk, which may be dominated by particulate mass. • The dust–haze effects were modified by season and individual-specific factors. - This study extends our understanding of the health impact of dust–haze in southern China, and provides local evidence for health to advocate for improved air emissions control and strategies to reduce population exposure

  5. Seasonal survival rates and causes of mortality of Little Owls in Denmark

    DEFF Research Database (Denmark)

    Thorup, Kasper; Pedersen, Dorthe; Sunde, Peter

    2013-01-01

    Survival rate is an essential component of population dynamics; therefore, identification of variation in mortality rates and the factors that influence them might be of key importance in understanding why populations increase or decrease. In Denmark, the Little Owl Athene noctua, a species...... the causes of current survival rates, we estimated age- and season-specific survival rates and causes of mortality in Danish Little Owls on the basis of ringed birds 1920–2002, radio tagged adult and juveniles 2005–2008 and nest surveys 2006–2008. We estimate that 32 % of all eggs fledge and survive to 2...... the breeding season. In radio-tagged adults and fledged juveniles, accidents in buildings and other human infrastructures were responsible for two-thirds of all fatalities. Anthropogenic habitats currently comprise the nesting and roosting habitats for the last Danish Little Owls. The accidental deaths...

  6. The influence of the bottom cold water on the seasonal variability of the Tsushima warm current

    Science.gov (United States)

    Isobe, Atsuhiko

    1995-06-01

    Previous studies have concluded that the volume transport and surface current velocity of the Tsushima Warm Current are at a maximum between summer and autumn and at a minimum between winter and spring. Each study has obtained these results indirectly, using the sea level difference across the Tsushima-Korea Strait or dynamic calculation. Numerical experiments are performed to estimate the seasonal variability in the sea level difference caused by the Bottom Cold Water (BCW), which intrudes from the Sea of Japan along the Korean coast in the bottom layer. These experiments basically treat the baroclinic adjustment problem of the BCW in a rectangular cross section perpendicular to the axis (northeast-southwest direction) of the Tsushima-Korea Strait. It is a five-layer model for summer and a two-layer model for winter. The initial conditions and parameters in models are chosen so as to match the calculated velocity-density fields with the observed velocity-density fields [Isobe A., S. Tawara, A. Kaneko and M. Kawano (1994) Continental Shelf Research, 14, 23-35.]. Consequently, the experiments prove that the observed seasonal variability in the sea level difference across the Tsushima-Korea Strait largely contains the baroclinic motion caused by the BCW. It should be noted that the position of the BCW also plays an important role in producing a considerable seasonal variation of the sea level difference. It is critical to remove the baroclinic contribution from the observed sea level differences across the Tsushima-Korea Strait in order to estimate the seasonal variation in the volume transport of the Tsushima Warm Current.

  7. Human mortality impacts of the 2015 summer heat spells in Slovakia

    Science.gov (United States)

    Výberči, Dalibor; Labudová, Lívia; Eštóková, Milada; Faško, Pavol; Trizna, Milan

    2017-07-01

    In 2015, Central Europe experienced an unusually warm summer season. For a great majority of climatic stations around Slovakia, it had been the warmest summer ever recorded over their entire instrumental observation period. In this study, we investigate the mortality effects of hot days' sequences during that particular summer on the Slovak population. In consideration of the range of available mortality data, the position of 2015 is analysed within the years 1996-2015. Over the given 20-year period, the summer heat spells of 2015 were by far the most severe from a meteorological point of view, and clearly the deadliest with the total of almost 540 excess deaths. In terms of impacts, an extraordinary 10-day August heat spell was especially remarkable. The massive lethal effects of heat would have likely been even more serious under normal circumstances, since the number of premature deaths appeared to be partially reduced due to a non-standard mortality pattern in the first quarter of the year. The heat spells of the extremely warm summer of 2015 in Slovakia are notable not just for their short-term response in mortality. It appears that in a combination with the preceding strong influenza season, they subsequently affected mortality conditions in the country in the following months up until the end of the year. The impacts described above were rather different for selected population subgroups (men and women, the elderly). Both separately and as a part of the annual mortality cycle, the 2015 summer heat spells may represent a particularly valuable source of information for public health.

  8. Impact of covariate models on the assessment of the air pollution-mortality association in a single- and multipollutant context.

    Science.gov (United States)

    Sacks, Jason D; Ito, Kazuhiko; Wilson, William E; Neas, Lucas M

    2012-10-01

    With the advent of multicity studies, uniform statistical approaches have been developed to examine air pollution-mortality associations across cities. To assess the sensitivity of the air pollution-mortality association to different model specifications in a single and multipollutant context, the authors applied various regression models developed in previous multicity time-series studies of air pollution and mortality to data from Philadelphia, Pennsylvania (May 1992-September 1995). Single-pollutant analyses used daily cardiovascular mortality, fine particulate matter (particles with an aerodynamic diameter ≤2.5 µm; PM(2.5)), speciated PM(2.5), and gaseous pollutant data, while multipollutant analyses used source factors identified through principal component analysis. In single-pollutant analyses, risk estimates were relatively consistent across models for most PM(2.5) components and gaseous pollutants. However, risk estimates were inconsistent for ozone in all-year and warm-season analyses. Principal component analysis yielded factors with species associated with traffic, crustal material, residual oil, and coal. Risk estimates for these factors exhibited less sensitivity to alternative regression models compared with single-pollutant models. Factors associated with traffic and crustal material showed consistently positive associations in the warm season, while the coal combustion factor showed consistently positive associations in the cold season. Overall, mortality risk estimates examined using a source-oriented approach yielded more stable and precise risk estimates, compared with single-pollutant analyses.

  9. The effects of dust–haze on mortality are modified by seasons and individual characteristics in Guangzhou, China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Tao [Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou 511430 (China); Environment and Health, Guangdong Provincial Key Medical Discipline of Twelfth Five-Year Plan, Guangzhou 511430 (China); Zhang, Yong Hui [Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430 (China); Xu, Yan Jun [Institute of Chronic Noncommunicable Disease Prevention and Control, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430 (China); Lin, Hua Liang [Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou 511430 (China); Environment and Health, Guangdong Provincial Key Medical Discipline of Twelfth Five-Year Plan, Guangzhou 511430 (China); Xu, Xiao Jun [Institute of Chronic Noncommunicable Disease Prevention and Control, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430 (China); Luo, Yuan; Xiao, JianPeng; Zeng, Wei Lin [Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, No. 160, Qunxian Road, Panyu District, Guangzhou 511430 (China); Environment and Health, Guangdong Provincial Key Medical Discipline of Twelfth Five-Year Plan, Guangzhou 511430 (China); Zhang, Wan Fang [Liwan Center for Disease Control and Prevention, Guangzhou 510176 (China); Chu, Cordia; Keogh, Kandice; Rutherford, Shannon [Griffith University, Brisbane 4111 (Australia); Qian, Zhengmin [Department of Epidemiology, School of Public Health, Saint Louis University, Saint Louis, MO 63104 (United States); Du, Yao Dong [Climate Center of Guangdong Province, Guangzhou 510080 (China); others, and

    2014-04-01

    This study aimed to investigate the effects of dust–haze on mortality and to estimate the seasonal and individual-specific modification effects in Guangzhou, China. Mortality, air pollution and meteorological data were collected for 2006–2011. A dust–haze day was defined as daily visibility <10 km with relative humidity <90%. This definition was further divided into light (8–10 km), medium (5–8 km) and heavy dust–haze (<5 km). A distributed lag linear model (DLM) was employed. Light, medium and heavy dust–haze days were associated with increased mortality of 3.4%, 6.8% and 10.4% respectively, at a lag of 0–6 days. This effect was more pronounced during the cold season, for cardiovascular mortality (CVD), respiratory mortality (RESP), in males and people ≥60years. These effects became insignificant after adjustment for PM{sub 10}. We concluded that dust–haze significantly increased mortality risk in Guangzhou, China, and this effect appears to be dominated by particulate mass and modified by season and individual-specific factors. - Highlights: • We assessed the health impact of dust–haze in a megacity of southern China. • A dust–haze was defined according to visibility and relative humidity. • Dust–haze increased mortality risk, which may be dominated by particulate mass. • The dust–haze effects were modified by season and individual-specific factors. - This study extends our understanding of the health impact of dust–haze in southern China, and provides local evidence for health to advocate for improved air emissions control and strategies to reduce population exposure.

  10. Mortality Attributable to Seasonal Influenza A and B Infections in Thailand, 2005–2009: A Longitudinal Study

    Science.gov (United States)

    Cooper, Ben S.; Kotirum, Surachai; Kulpeng, Wantanee; Praditsitthikorn, Naiyana; Chittaganpitch, Malinee; Limmathurotsakul, Direk; Day, Nicholas P. J.; Coker, Richard; Teerawattananon, Yot; Meeyai, Aronrag

    2015-01-01

    Influenza epidemiology differs substantially in tropical and temperate zones, but estimates of seasonal influenza mortality in developing countries in the tropics are lacking. We aimed to quantify mortality due to seasonal influenza in Thailand, a tropical middle-income country. Time series of polymerase chain reaction–confirmed influenza infections between 2005 and 2009 were constructed from a sentinel surveillance network. These were combined with influenza-like illness data to derive measures of influenza activity and relationships to mortality by using a Bayesian regression framework. We estimated 6.1 (95% credible interval: 0.5, 12.4) annual deaths per 100,000 population attributable to influenza A and B, predominantly in those aged ≥60 years, with the largest contribution from influenza A(H1N1) in 3 out of 4 years. For A(H3N2), the relationship between influenza activity and mortality varied over time. Influenza was associated with increases in deaths classified as resulting from respiratory disease (posterior probability of positive association, 99.8%), cancer (98.6%), renal disease (98.0%), and liver disease (99.2%). No association with circulatory disease mortality was found. Seasonal influenza infections are associated with substantial mortality in Thailand, but evidence for the strong relationship between influenza activity and circulatory disease mortality reported in temperate countries is lacking. PMID:25899091

  11. Warm season grass establishment (in one year without the weeds)

    International Nuclear Information System (INIS)

    Downing, D.

    1998-01-01

    Native warm season grasses, big bluestem and indian, were established by the broadcast method on a relatively large area (130 acres) of reclaimed coal surface-mined land in Perry County, Illinois. Existing vegetation was controlled using two quarts of Round-Up and 12 ounces of Plateau per acre the first week of May. Five pounds of pure live seed of both species were applied by airflow using 100 pounds per acre of 0-46-0 and 100 pounds per acre of 0-0-60, primarily to carry the seed. The surface was cultipacked to insure good seed to soil contact. Planting was initiated and completed the last week of June. An estimated 95% to 100% ground cover was evident by mid to late August. By mid September, numerous big blue stem flower/seed stalks were noticeable

  12. Prolonged warm ischemia time is associated with graft failure and mortality after kidney transplantation.

    Science.gov (United States)

    Tennankore, Karthik K; Kim, S Joseph; Alwayn, Ian P J; Kiberd, Bryce A

    2016-03-01

    Warm ischemia time is a potentially modifiable insult to transplanted kidneys, but little is known about its effect on long-term outcomes. Here we conducted a study of United States kidney transplant recipients (years 2000-2013) to determine the association between warm ischemia time (the time from organ removal from cold storage to reperfusion with warm blood) and death/graft failure. Times under 10 minutes were potentially attributed to coding error. Therefore, the 10-to-under-20-minute interval was chosen as the reference group. The primary outcome was mortality and graft failure (return to chronic dialysis or preemptive retransplantation) adjusted for recipient, donor, immunologic, and surgical factors. The study included 131,677 patients with 35,901 events. Relative to the reference patients, times of 10 to under 20, 20 to under 30, 30 to under 40, 40 to under 50, 50 to under 60, and 60 and more minutes were associated with hazard ratios of 1.07 (95% confidence interval, 0.99-1.15), 1.13 (1.06-1.22), 1.17 (1.09-1.26), 1.20 (1.12-1.30), and 1.23 (1.15-1.33) for the composite event, respectively. Association between prolonged warm ischemia time and death/graft failure persisted after stratification by donor type (living vs. deceased donor) and delayed graft function status. Thus, warm ischemia time is associated with adverse long-term patient and graft survival after kidney transplantation. Identifying strategies to reduce warm ischemia time is an important consideration for future study. Copyright © 2015 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  13. Seasonal variation in cause-specific mortality: are there high-risk groups? 25-year follow-up of civil servants from the first Whitehall study

    NARCIS (Netherlands)

    C.T.M. van Rossum (Caroline); M.J. Shipley; H. Hemingway; D.E. Grobbee (Diederick); J.P. Mackenbach (Johan); M.G. Marmot

    2001-01-01

    textabstractOBJECTIVES: To determine the seasonal effect on all-cause and cause-specific mortality and to identify high-risk groups. METHODS: A 25-year follow-up of 19,019 male civil servants aged 40-69 years. RESULTS: All-cause mortality was seasonal (ratio of highest mortality

  14. Effects of Global Warming on Predatory Bugs Supported by Data Across Geographic and Seasonal Climatic Gradients

    Science.gov (United States)

    Schuldiner-Harpaz, Tarryn; Coll, Moshe

    2013-01-01

    Global warming may affect species abundance and distribution, as well as temperature-dependent morphometric traits. In this study, we first used historical data to document changes in Orius (Heteroptera: Anthocoridae) species assemblage and individual morphometric traits over the past seven decades in Israel. We then tested whether these changes could have been temperature driven by searching for similar patterns across seasonal and geographic climatic gradients in a present survey. The historical records indicated a shift in the relative abundance of dominant Orius species; the relative abundance of O. albidipennis, a desert-adapted species, increased while that of O. laevigatus decreased in recent decades by 6 and 10–15 folds, respectively. These shifts coincided with an overall increase of up to 2.1°C in mean daily temperatures over the last 25 years in Israel. Similar trends were found in contemporary data across two other climatic gradients, seasonal and geographic; O. albidipennis dominated Orius assemblages under warm conditions. Finally, specimens collected in the present survey were significantly smaller than those from the 1980’s, corresponding to significantly smaller individuals collected now during warmer than colder seasons. Taken together, results provide strong support to the hypothesis that temperature is the most likely driver of the observed shifts in species composition and body sizes because (1) historical changes in both species assemblage and body size were associated with rising temperatures in the study region over the last few decades; and (2) similar changes were observed as a result of contemporary drivers that are associated with temperature. PMID:23805249

  15. How do drought and warming influence survival and wood traits of Picea mariana saplings?

    Science.gov (United States)

    Balducci, Lorena; Deslauriers, Annie; Giovannelli, Alessio; Beaulieu, Marilène; Delzon, Sylvain; Rossi, Sergio; Rathgeber, Cyrille B K

    2015-01-01

    Warming and drought will occur with increased frequency and intensity at high latitudes in the future. How heat and water stress can influence tree mortality is incompletely understood. The aim of this study was to evaluate how carbon resources, stem hydraulics, and wood anatomy and density determine the ability of black spruce saplings to survive daytime or night-time warming (+ 6 °C in comparison with control) in combination with a drought period. Plant water relations, the dynamics of non-structural carbohydrates and starch, mortality rate, and wood anatomy and density of saplings were monitored. Warming, in conjunction with 25 d of water deficit, increased sapling mortality (10% and 20% in night-time and daytime warming, respectively) compared with the control conditions (0.8%). Drought substantially decreased gas exchange, and also pre-dawn and mid-day leaf water potential to values close to -3MPa which probably induced xylem embolism (xylem air entry point, P₁₂, being on average around -3MPa for this species). In addition, the recovery of gas exchange never reached the initial pre-stress levels, suggesting a possible loss of xylem hydraulic conductivity associated with cavitation. Consequently, mortality may be due to xylem hydraulic failure. Warmer temperatures limited the replenishment of starch reserves after their seasonal minimum. Lighter wood was formed during the drought period, reflecting a lower carbon allocation to cell wall formation, preventing the adaptation of the hydraulic system to drought. Saplings of black spruce experienced difficulty in adapting under climate change conditions, which might compromise their survival in the future. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. Trait acclimation mitigates mortality risks of tropical canopy trees under global warming

    Directory of Open Access Journals (Sweden)

    Frank eSterck

    2016-05-01

    Full Text Available There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and – the notoriously unknown – physiological trait acclimation of trees. In this opinion article we provided a first quantification of the potential of trait acclimation to mitigate the negative effects of warming on tropical canopy tree growth and survival. We applied a physiological tree growth model that incorporates trait acclimation through an optimization approach. Our model estimated the maximum effect of acclimation when trees optimize traits that are strongly plastic on a week to annual time scale (leaf photosynthetic capacity, total leaf area, stem sapwood area to maximize carbon gain. We simulated tree carbon gain for temperatures (25-35ºC and ambient CO2 concentrations (390-800 ppm predicted for the 21st century. Full trait acclimation increased simulated carbon gain by up to 10-20% and the maximum tolerated temperature by up to 2ºC, thus reducing risks of tree death under predicted warming. Functional trait acclimation may thus increase the resilience of tropical trees to warming, but cannot prevent tree death during extremely hot and dry years at current CO2 levels. We call for incorporating trait acclimation in field and experimental studies of plant functional traits, and in models that predict responses of tropical forests to climate change.

  17. Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming

    Science.gov (United States)

    Sterck, Frank; Anten, Niels P. R.; Schieving, Feike; Zuidema, Pieter A.

    2016-01-01

    There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and – the notoriously unknown – physiological trait acclimation of trees. In this opinion article we provided a first quantification of the potential of trait acclimation to mitigate the negative effects of warming on tropical canopy tree growth and survival. We applied a physiological tree growth model that incorporates trait acclimation through an optimization approach. Our model estimated the maximum effect of acclimation when trees optimize traits that are strongly plastic on a week to annual time scale (leaf photosynthetic capacity, total leaf area, stem sapwood area) to maximize carbon gain. We simulated tree carbon gain for temperatures (25–35°C) and ambient CO2 concentrations (390–800 ppm) predicted for the 21st century. Full trait acclimation increased simulated carbon gain by up to 10–20% and the maximum tolerated temperature by up to 2°C, thus reducing risks of tree death under predicted warming. Functional trait acclimation may thus increase the resilience of tropical trees to warming, but cannot prevent tree death during extremely hot and dry years at current CO2 levels. We call for incorporating trait acclimation in field and experimental studies of plant functional traits, and in models that predict responses of tropical forests to climate change. PMID:27242814

  18. Tree mortality from fire and bark beetles following early and late season prescribed fires in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Schwilk, Dylan W.; Knapp, Eric E.; Ferrenberg, Scott; Keeley, Jon E.; Caprio, Anthony C.

    2006-01-01

    Over the last century, fire exclusion in the forests of the Sierra Nevada has allowed surface fuels to accumulate and has led to increased tree density. Stand composition has also been altered as shade tolerant tree species crowd out shade intolerant species. To restore forest structure and reduce the risk of large, intense fires, managers have increasingly used prescription burning. Most fires prior to EuroAmerican settlement occurred during the late summer and early fall and most prescribed burning has taken place during the latter part of this period. Poor air quality and lack of suitable burn windows during the fall, however, have resulted in a need to conduct more prescription burning earlier in the season. Previous reports have suggested that burning during the time when trees are actively growing may increase mortality rates due to fine root damage and/or bark beetle activity. This study examines the effects of fire on tree mortality and bark beetle attacks under prescription burning during early and late season. Replicated early season burn, late season burn and unburned control plots were established in an old-growth mixed conifer forest in the Sierra Nevada that had not experienced a fire in over 120 years. Although prescribed burns resulted in significant mortality of particularly the smallest tree size classes, no difference between early and late season burns was detected. Direct mortality due to fire was associated with fire intensity. Secondary mortality due to bark beetles was not significantly correlated with fire intensity. The probability of bark beetle attack on pines did not differ between early and late season burns, while the probability of bark beetle attack on firs was greater following early season burns. Overall tree mortality appeared to be primarily the result of fire intensity rather than tree phenology at the time of the burns. Early season burns are generally conducted under higher fuel moisture conditions, leading to less fuel

  19. Darcy’s law predicts widespread forest mortality under climate warming

    Science.gov (United States)

    McDowell, Nate G.; Allen, Craig D.

    2015-01-01

    Drought and heat-induced tree mortality is accelerating in many forest biomes as a consequence of a warming climate, resulting in a threat to global forests unlike any in recorded history. Forests store the majority of terrestrial carbon, thus their loss may have significant and sustained impacts on the global carbon cycle. We use a hydraulic corollary to Darcy’s law, a core principle of vascular plant physiology, to predict characteristics of plants that will survive and die during drought under warmer future climates. Plants that are tall with isohydric stomatal regulation, low hydraulic conductance, and high leaf area are most likely to die from future drought stress. Thus, tall trees of old-growth forests are at the greatest risk of loss, which has ominous implications for terrestrial carbon storage. This application of Darcy’s law indicates today’s forests generally should be replaced by shorter and more xeric plants, owing to future warmer droughts and associated wildfires and pest attacks. The Darcy’s corollary also provides a simple, robust framework for informing forest management interventions needed to promote the survival of current forests. Given the robustness of Darcy’s law for predictions of vascular plant function, we conclude with high certainty that today’s forests are going to be subject to continued increases in mortality rates that will result in substantial reorganization of their structure and carbon storage.

  20. Mortality Associated With Seasonal and Pandemic Influenza Among Pregnant and Nonpregnant Women of Childbearing Age in a High-HIV-Prevalence Setting-South Africa, 1999-2009.

    Science.gov (United States)

    Tempia, Stefano; Walaza, Sibongile; Cohen, Adam L; von Mollendorf, Claire; Moyes, Jocelyn; McAnerney, Johanna M; Cohen, Cheryl

    2015-10-01

    Information on the mortality burden associated with seasonal and pandemic influenza virus infection among pregnant women is scarce in most settings, particularly in sub-Saharan Africa where pregnancy and maternal mortality rates as well as human immunodeficiency virus (HIV) prevalence are elevated. We used an ecological study design to estimate the seasonal and A(H1N1)pdm09 influenza-associated mortality among pregnant and nonpregnant women of childbearing age (15-49 years) by HIV serostatus during 1999-2009 in South Africa. Mortality rates were expressed per 100 000 person-years. During 1999-2009, the estimated mean annual seasonal influenza-associated mortality rates were 12.6 (123 deaths) and 7.3 (914 deaths) among pregnant and nonpregnant women, respectively. Among pregnant women, the estimated mean annual seasonal influenza-associated mortality rates were 74.9 (109 deaths) among HIV-infected and 1.5 (14 deaths) among HIV-uninfected individuals. Among nonpregnant women, the estimated mean annual seasonal influenza-associated mortality rate was 41.2 (824 deaths) among HIV-infected and 0.9 (90 deaths) among HIV-uninfected individuals. Pregnant women experienced an increased risk of seasonal influenza-associated mortality compared with nonpregnant women (relative risk [RR], 2.8; 95% confidence interval [CI], 1.7-3.9). In 2009, the estimated influenza A(H1N1)pdm09-associated mortality rates were 19.3 (181 deaths) and 9.4 (1189 deaths) among pregnant and nonpregnant women, respectively (RR, 3.2; 95% CI, 2.3-4.1). Among women of childbearing age, the majority of estimated seasonal influenza-associated deaths occurred in HIV-infected individuals. Pregnant women experienced an increased risk of death associated with seasonal and A(H1N1)pdm09 influenza infection compared with nonpregnant women. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. Morbidity, Mortality, and Seasonality of Influenza Hospitalizations in Egypt, November 2007-November 2014.

    Directory of Open Access Journals (Sweden)

    Amr Kandeel

    Full Text Available Influenza typically comprises a substantial portion of acute respiratory infections, a leading cause of mortality worldwide. However, influenza epidemiology data are lacking in Egypt. We describe seven years of Egypt's influenza hospitalizations from a multi-site influenza surveillance system.Syndromic case definitions identified individuals with severe acute respiratory infection (SARI admitted to eight hospitals in Egypt. Standardized demographic and clinical data were collected. Nasopharyngeal and oropharyngeal swabs were tested for influenza using real-time reverse transcription polymerase chain reaction and typed as influenza A or B, and influenza A specimens subtyped.From November 2007-November 2014, 2,936/17,441 (17% SARI cases were influenza-positive. Influenza-positive patients were more likely to be older, female, pregnant, and have chronic condition(s (all p<0.05. Among them, 53 (2% died, and death was associated with older age, five or more days from symptom onset to hospitalization, chronic condition(s, and influenza A (all p<0.05. An annual seasonal influenza pattern occurred from July-June. Each season, the proportion of the season's influenza-positive cases peaked during November-May (19-41%.In Egypt, influenza causes considerable morbidity and mortality and influenza SARI hospitalization patterns mirror those of the Northern Hemisphere. Additional assessment of influenza epidemiology in Egypt may better guide disease control activities and vaccine policy.

  2. Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

    Science.gov (United States)

    Freund, Mandy; Henley, Benjamin J.; Karoly, David J.; Allen, Kathryn J.; Baker, Patrick J.

    2017-11-01

    Australian seasonal rainfall is strongly affected by large-scale ocean-atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April-September) and warm (October-March) season rainfall in eight natural resource management (NRM) regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997-2009) appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental period (Federation Drought

  3. Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

    Directory of Open Access Journals (Sweden)

    M. Freund

    2017-11-01

    Full Text Available Australian seasonal rainfall is strongly affected by large-scale ocean–atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April–September and warm (October–March season rainfall in eight natural resource management (NRM regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997–2009 appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental

  4. Seasonal hydroclimatic impacts of Sun Corridor expansion

    International Nuclear Information System (INIS)

    Georgescu, M; Mahalov, A; Moustaoui, M

    2012-01-01

    Conversion of natural to urban land forms imparts influence on local and regional hydroclimate via modification of the surface energy and water balance, and consideration of such effects due to rapidly expanding megapolitan areas is necessary in light of the growing global share of urban inhabitants. Based on a suite of ensemble-based, multi-year simulations using the Weather Research and Forecasting (WRF) model, we quantify seasonally varying hydroclimatic impacts of the most rapidly expanding megapolitan area in the US: Arizona’s Sun Corridor, centered upon the Greater Phoenix metropolitan area. Using a scenario-based urban expansion approach that accounts for the full range of Sun Corridor growth uncertainty through 2050, we show that built environment induced warming for the maximum development scenario is greatest during the summer season (regionally averaged warming over AZ exceeds 1 °C). Warming remains significant during the spring and fall seasons (regionally averaged warming over AZ approaches 0.9 °C during both seasons), and is least during the winter season (regionally averaged warming over AZ of 0.5 °C). Impacts from a minimum expansion scenario are reduced, with regionally averaged warming ranging between 0.1 and 0.3 °C for all seasons except winter, when no warming impacts are diagnosed. Integration of highly reflective cool roofs within the built environment, increasingly recognized as a cost-effective option intended to offset the warming influence of urban complexes, reduces urban-induced warming considerably. However, impacts on the hydrologic cycle are aggravated via enhanced evapotranspiration reduction, leading to a 4% total accumulated precipitation decrease relative to the non-adaptive maximum expansion scenario. Our results highlight potentially unintended consequences of this adaptation approach within rapidly expanding megapolitan areas, and emphasize the need for undeniably sustainable development paths that account for

  5. Amplified Arctic warming by phytoplankton under greenhouse warming.

    Science.gov (United States)

    Park, Jong-Yeon; Kug, Jong-Seong; Bader, Jürgen; Rolph, Rebecca; Kwon, Minho

    2015-05-12

    Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical-ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean-atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes.

  6. Spatial and temporal characteristics of warm season convection over Pearl River Delta region, China, based on 3 years of operational radar data

    Science.gov (United States)

    Chen, Xingchao; Zhao, Kun; Xue, Ming

    2014-11-01

    This study examines the temporal and spatial characteristics and distributions of convection over the Pearl River Delta region of Guangzhou, China, during the May-September warm season, using, for the first time for such a purpose, 3 years of operational Doppler radar data in the region. Results show that convective features occur most frequently along the southern coast and the windward slope of the eastern mountainous area of Pearl River Delta, with the highest frequency occurring in June and the lowest in September among the 5 months. The spatial frequency distribution pattern also roughly matches the accumulated precipitation pattern. The occurrence of convection in this region also exhibits strong diurnal cycles. During May and June, the diurnal distribution is bimodal, with the maximum frequency occurring in the early afternoon and a secondary peak occurring between midnight and early morning. The secondary peak is much weaker in July, August, and September. Convection near the coast is found to occur preferentially on days when a southerly low-level jet (LLJ) exists, especially during the Meiyu season. Warm, moist, and unstable air is transported from the ocean to land by LLJs on these days, and the lifting along the coast by convergence induced by differential surface friction between the land and ocean is believed to be the primary cause for the high frequency along the coast. In contrast, the high frequency over mountainous area is believed to be due to orographic lifting of generally southerly flows during the warm season.

  7. How does the dengue vector mosquito Aedes albopictus respond to global warming?

    Science.gov (United States)

    Jia, Pengfei; Chen, Xiang; Chen, Jin; Lu, Liang; Liu, Qiyong; Tan, Xiaoyue

    2017-03-11

    Global warming has a marked influence on the life cycle of epidemic vectors as well as their interactions with human beings. The Aedes albopictus mosquito as the vector of dengue fever surged exponentially in the last decade, raising ecological and epistemological concerns of how climate change altered its growth rate and population dynamics. As the global warming pattern is considerably uneven across four seasons, with a confirmed stronger effect in winter, an emerging need arises as to exploring how the seasonal warming effects influence the annual development of Ae. albopictus. The model consolidates a 35-year climate dataset and designs fifteen warming patterns that increase the temperature of selected seasons. Based on a recently developed mechanistic population model of Ae. albopictus, the model simulates the thermal reaction of blood-fed adults by systematically increasing the temperature from 0.5 to 5 °C at an interval of 0.5 °C in each warming pattern. The results show the warming effects are different across seasons. The warming effects in spring and winter facilitate the development of the species by shortening the diapause period. The warming effect in summer is primarily negative by inhibiting mosquito development. The warming effect in autumn is considerably mixed. However, these warming effects cannot carry over to the following year, possibly due to the fact that under the extreme weather in winter the mosquito fully ceases from development and survives in terms of diapause eggs. As the historical pattern of global warming manifests seasonal fluctuations, this study provides corroborating and previously ignored evidence of how such seasonality affects the mosquito development. Understanding this short-term temperature-driven mechanism as one chain of the transmission events is critical to refining the thermal reaction norms of the epidemic vector under global warming as well as developing effective mosquito prevention and control strategies.

  8. Seasonal patterns in soil N availability in the arctic tundra in response to accelerated snowmelt and warming

    Science.gov (United States)

    Darrouzet-Nardi, A.; Wallenstein, M. D.; Steltzer, H.; Sullivan, P.; Melle, C.; Segal, A.; Weintraub, M. N.

    2010-12-01

    Arctic soils contain large stocks of carbon (C) and may act as a significant CO2 source in response to climate warming. However, nitrogen (N) availability limits both plant growth and decomposition in many Arctic sites, and may thus be a key constraint on climate-carbon feedbacks. While current models of tundra ecosystems and their responses to climate change assume that N limits plant growth and C limits decomposition, there is strong evidence to the contrary showing that N can also limit decomposition. For example, the production of both new microbial biomass and enzymes that degrade organic matter appear to be limited by N during the summer. N availability is strongly seasonal: we have previously observed relatively high availability early in the growing season followed by a pronounced crash in tussock tundra soils. To investigate the drivers of N availability throughout the season, we used a field manipulation of tussock tundra growing season length (~4 days acceleration of snowmelt) and air temperature (open top chambers) and a laboratory soil N addition in both early and late season. Nutrient availability throughout the field season was measured at high temporal resolution (25 measurements from soil thaw through early plant senescence). Results from a laboratory experiment in which N was added to early season and late season soils suggests that soil respiration is in fact N limited at both times of the season, though this limitation is temperature dependent with effects most pronounced at 10°C. High-resolution measurements of nutrients in the soil solution and extractable N throughout the season showed that although a nutrient crash in N can be observed mid-season, N availability can still fluctuate later in the season. Finally, effects of the extended growing season and increased air temperature have so far had few effects on soil nutrient N dynamics throughout the summer growing season, suggesting either an insensitivity of N availability to these

  9. Chytridiomycosis and seasonal mortality of tropical stream-associated frogs 15 years after introduction of Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Phillott, Andrea D; Grogan, Laura F; Cashins, Scott D; McDonald, Keith R; Berger, Lee; Skerratt, Lee F

    2013-10-01

    Assessing the effects of diseases on wildlife populations can be difficult in the absence of observed mortalities, but it is crucial for threat assessment and conservation. We performed an intensive capture-mark-recapture study across seasons and years to investigate the effect of chytridiomycosis on demographics in 2 populations of the threatened common mist frog (Litoria rheocola) in the lowland wet tropics of Queensland, Australia. Infection prevalence was the best predictor for apparent survival probability in adult males and varied widely with season (0-65%). Infection prevalence was highest in winter months when monthly survival probabilities were low (approximately 70%). Populations at both sites exhibited very low annual survival probabilities (12-15%) but high recruitment (71-91%), which resulted in population growth rates that fluctuated seasonally. Our results suggest that even in the absence of observed mortalities and continued declines, and despite host-pathogen co-existence for multiple host generations over almost 2 decades, chytridiomycosis continues to have substantial seasonally fluctuating population-level effects on amphibian survival, which necessitates increased recruitment for population persistence. Similarly infected populations may thus be under continued threat from chytridiomycosis which may render them vulnerable to other threatening processes, particularly those affecting recruitment success. © 2013 Society for Conservation Biology.

  10. Influenza epidemics, seasonality, and the effects of cold weather on cardiac mortality

    Science.gov (United States)

    2012-01-01

    Background More people die in the winter from cardiac disease, and there are competing hypotheses to explain this. The authors conducted a study in 48 US cities to determine how much of the seasonal pattern in cardiac deaths could be explained by influenza epidemics, whether that allowed a more parsimonious control for season than traditional spline models, and whether such control changed the short term association with temperature. Methods The authors obtained counts of daily cardiac deaths and of emergency hospital admissions of the elderly for influenza during 1992–2000. Quasi-Poisson regression models were conducted estimating the association between daily cardiac mortality, and temperature. Results Controlling for influenza admissions provided a more parsimonious model with better Generalized Cross-Validation, lower residual serial correlation, and better captured Winter peaks. The temperature-response function was not greatly affected by adjusting for influenza. The pooled estimated increase in risk for a temperature decrease from 0 to −5°C was 1.6% (95% confidence interval (CI) 1.1-2.1%). Influenza accounted for 2.3% of cardiac deaths over this period. Conclusions The results suggest that including epidemic data explained most of the irregular seasonal pattern (about 18% of the total seasonal variation), allowing more parsimonious models than when adjusting for seasonality only with smooth functions of time. The effect of cold temperature is not confounded by epidemics. PMID:23025494

  11. Experimental climate warming decreases photosynthetic efficiency of lichens in an arid South African ecosystem.

    Science.gov (United States)

    Maphangwa, Khumbudzo Walter; Musil, Charles F; Raitt, Lincoln; Zedda, Luciana

    2012-05-01

    Elevated temperatures and diminished precipitation amounts accompanying climate warming in arid ecosystems are expected to have adverse effects on the photosynthesis of lichen species sensitive to elevated temperature and/or water limitation. This premise was tested by artificially elevating temperatures (increase 2.1-3.8°C) and reducing the amounts of fog and dew precipitation (decrease 30.1-31.9%), in an approximation of future climate warming scenarios, using transparent hexagonal open-top warming chambers placed around natural populations of four lichen species (Xanthoparmelia austroafricana, X. hyporhytida , Xanthoparmelia. sp., Xanthomaculina hottentotta) at a dry inland site and two lichen species (Teloschistes capensis and Ramalina sp.) at a humid coastal site in the arid South African Succulent Karoo Biome. Effective photosynthetic quantum yields ([Formula: see text]) were measured hourly throughout the day at monthly intervals in pre-hydrated lichens present in the open-top warming chambers and in controls which comprised demarcated plots of equivalent open-top warming chamber dimensions constructed from 5-cm-diameter mesh steel fencing. The cumulative effects of the elevated temperatures and diminished precipitation amounts in the open-top warming chambers resulted in significant decreases in lichen [Formula: see text]. The decreases were more pronounced in lichens from the dry inland site (decline 34.1-46.1%) than in those from the humid coastal site (decline 11.3-13.7%), most frequent and prominent in lichens at both sites during the dry summer season, and generally of greatest magnitude at or after the solar noon in all seasons. Based on these results, we conclude that climate warming interacting with reduced precipitation will negatively affect carbon balances in endemic lichens by increasing desiccation damage and reducing photosynthetic activity time, leading to increased incidences of mortality.

  12. Nonintrusive field experiments show different plant responses to warming and drought among sites, seasons, and species in a north-south European gradient

    DEFF Research Database (Denmark)

    Penuelas, J.; Gordon, C.; Llorens, L.

    2004-01-01

    -limited. In the water-stressed southern site, there was no increase in total aboveground plant biomass growth as expected since warming increases water loss, and temperatures in those ecosystems are already close to the optimum for photosynthesis. The southern site presented instead the most negative response...... a 15% increase in total aboveground plant biomass growth in the UK site. Both direct and indirect effects of warming, such as longer growth season and increased nutrient availability, are likely to be particularly important in this and the other northern sites which tend to be temperature...... to the drought treatment consisting of a soil moisture reduction at the peak of the growing season ranging from 33% in the Spanish site to 82% in The Netherlands site. In the Spanish site there was a 14% decrease in total aboveground plant biomass growth relative to control. Flowering was decreased by drought...

  13. Validation of inverse seasonal peak mortality in medieval plagues, including the Black Death, in comparison to modern Yersinia pestis-variant diseases.

    Science.gov (United States)

    Welford, Mark R; Bossak, Brian H

    2009-12-22

    Recent studies have noted myriad qualitative and quantitative inconsistencies between the medieval Black Death (and subsequent "plagues") and modern empirical Y. pestis plague data, most of which is derived from the Indian and Chinese plague outbreaks of A.D. 1900+/-15 years. Previous works have noted apparent differences in seasonal mortality peaks during Black Death outbreaks versus peaks of bubonic and pneumonic plagues attributed to Y. pestis infection, but have not provided spatiotemporal statistical support. Our objective here was to validate individual observations of this seasonal discrepancy in peak mortality between historical epidemics and modern empirical data. We compiled and aggregated multiple daily, weekly and monthly datasets of both Y. pestis plague epidemics and suspected Black Death epidemics to compare seasonal differences in mortality peaks at a monthly resolution. Statistical and time series analyses of the epidemic data indicate that a seasonal inversion in peak mortality does exist between known Y. pestis plague and suspected Black Death epidemics. We provide possible explanations for this seasonal inversion. These results add further evidence of inconsistency between historical plagues, including the Black Death, and our current understanding of Y. pestis-variant disease. We expect that the line of inquiry into the disputed cause of the greatest recorded epidemic will continue to intensify. Given the rapid pace of environmental change in the modern world, it is crucial that we understand past lethal outbreaks as fully as possible in order to prepare for future deadly pandemics.

  14. The Effects of Fine Particulate Air Pollution on Daily Mortality: A Case-Crossover Study in a Subtropical City, Taipei, Taiwan

    Directory of Open Access Journals (Sweden)

    Shang-Shyue Tsai

    2014-05-01

    Full Text Available This study was undertaken to determine whether there was an association between PM2.5 levels and daily mortality in Taipei, Taiwan, the largest metropolitan city with a subtropical climate. Daily mortality, air pollution, and weather data for Taipei were obtained for the period from 2006–2008. The relative risk of daily mortality was estimated using a time-stratified case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single pollutant model, PM2.5 showed association with total mortality both on warm (>23 °C and cool days (<23 °C. There is no indication of an association between PM2.5 and risk of death due to respiratory diseases both on warm and cool days. PM2.5 had effects on the risk of death from cardiovascular diseases only on cool days. In the two-pollutant models, PM2.5 remained effects on the risk of mortality for all cause and cardiovascular disease after the inclusion of SO2 and O3 both on warm and cool days. This study provides evidence that short-term exposure to PM2.5 increased the risk of death for all cause and cardiovascular disease.

  15. Protozoans bacterivory in a subtropical environment during a dry/cold and a rainy/warm season

    Directory of Open Access Journals (Sweden)

    Karina F. Hisatugo

    2014-01-01

    Full Text Available In aquatic ecosystems, bacteria are controlled by several organisms in the food chain, such as protozoa, that use them as food source. This study aimed to quantify the ingestion and clearance rates of bacteria by ciliates and heterotrophic nanoflagellates (HNF in a subtropical freshwater reservoir (Monjolinho reservoir -São Carlos -Brazil during one year period, in order to verify their importance as consumers and controllers of bacteria in two seasons, a dry/cold and a rainy/warm one. For this purpose, in situ bacterivory experiments were carried out bimonthly using fluorescently labeled bacteria with 5-(4,6 diclorotriazin-2yl aminofluorescein (DTAF. Although ciliates have shown the highest individual ingestion and clearance rates, bacterivory was dominated by HNF, who showed higher population ingestion rates (mean of 9,140 bacteria h-1mL-1 when compared to ciliates (mean of 492 bacteria h-1mL-1. The greater predation impact on bacterial communities was caused mainly by the small HNF (< 5 µm population, especially in the rainy season, probably due to the abundances of these organisms, the precipitation, trophic index state and water temperature that were higher in this period. Thus, the protozoan densities together with environmental variables were extremely relevant in determining the seasonal pattern of bacterivory in Monjolinho reservoir.

  16. Validation of inverse seasonal peak mortality in medieval plagues, including the Black Death, in comparison to modern Yersinia pestis-variant diseases.

    Directory of Open Access Journals (Sweden)

    Mark R Welford

    Full Text Available BACKGROUND: Recent studies have noted myriad qualitative and quantitative inconsistencies between the medieval Black Death (and subsequent "plagues" and modern empirical Y. pestis plague data, most of which is derived from the Indian and Chinese plague outbreaks of A.D. 1900+/-15 years. Previous works have noted apparent differences in seasonal mortality peaks during Black Death outbreaks versus peaks of bubonic and pneumonic plagues attributed to Y. pestis infection, but have not provided spatiotemporal statistical support. Our objective here was to validate individual observations of this seasonal discrepancy in peak mortality between historical epidemics and modern empirical data. METHODOLOGY/PRINCIPAL FINDINGS: We compiled and aggregated multiple daily, weekly and monthly datasets of both Y. pestis plague epidemics and suspected Black Death epidemics to compare seasonal differences in mortality peaks at a monthly resolution. Statistical and time series analyses of the epidemic data indicate that a seasonal inversion in peak mortality does exist between known Y. pestis plague and suspected Black Death epidemics. We provide possible explanations for this seasonal inversion. CONCLUSIONS/SIGNIFICANCE: These results add further evidence of inconsistency between historical plagues, including the Black Death, and our current understanding of Y. pestis-variant disease. We expect that the line of inquiry into the disputed cause of the greatest recorded epidemic will continue to intensify. Given the rapid pace of environmental change in the modern world, it is crucial that we understand past lethal outbreaks as fully as possible in order to prepare for future deadly pandemics.

  17. Warm fresh whole blood and thoracic traumain iraq and afghanistan.

    Science.gov (United States)

    Keneally, Ryan J; Parsons, Andrew M; Willett, Peter B

    2015-01-01

    Thoracic trauma occurred in 10% of the patients seen at US military treatment facilities in Iraq and Afghanistan and 52% of those patients were transfused. Among those transfused, 281 patients received warm fresh whole blood. A previous report documented improved survival with warm fresh whole blood in patients injured in combat without stratification by injury pattern. A later report described an increase in acute lung injuries after its administration. Survivorship and warm fresh whole blood have never been analyzed in a subpopulation at highest risk for lung injuries, such as patients with thoracic trauma. There may be a heterogeneous relationship between whole blood and survival based on likelihood of a concomitant pulmonary injury. In this report, the relationship between warm fresh whole blood and survivorship was analyzed among patients at highest risk for concomitant pulmonary injuries. Patients with thoracic trauma who received a transfusion were identified in the Joint Theater Trauma Registry. Gross mortality rates were compared between whole blood recipients and patients transfused with component therapy only. The association between each blood component and mortality was determined in a regression model. The overall mortality risk was compared between warm fresh whole blood recipients and non-recipients. Patients transfused with warm fresh whole blood in addition to component therapy had a higher mortality rate than patients transfused only separated blood components (21.3% vs. 12.8%, P warm fresh whole blood in addition to component therapy was not associated with increased mortality risk compared with the transfusion of component therapy only (OR 1.247 [95% CI 0.760-2.048], P = 0.382). Patients with combat related thoracic trauma transfused with warm fresh whole blood were not at increased risk for mortality compared to those who received component therapy alone when controlling for covariates.

  18. Escalating heat-stress mortality risk due to global warming in the Middle East and North Africa (MENA).

    Science.gov (United States)

    Ahmadalipour, Ali; Moradkhani, Hamid

    2018-08-01

    Climate change will substantially exacerbate extreme temperature and heatwaves. The impacts will be more intense across the Middle East and North Africa (MENA), a region mostly characterized by hot and arid climate, already intolerable for human beings in many parts. In this study, daily climate data from 17 fine-resolution Regional Climate Models (RCMs) are acquired to calculate wet-bulb temperature and investigate the mortality risk for people aged over 65 years caused by excessive heat stress across the MENA region. Spatially adaptive temperature thresholds are implemented for quantifying the mortality risk, and the analysis is conducted for the historical period of 1951-2005 and two future scenarios of RCP4.5 and RCP8.5 during the 2006-2100 period. Results show that the mortality risk will increase in distant future to 8-20 times higher than that of the historical period if no climate change mitigation is implemented. The coastal regions of the Red sea, Persian Gulf, and Mediterranean Sea indicate substantial increase in mortality risk. Nonetheless, the risk ratio will be limited to 3-7 times if global warming is limited to 2 °C. Climate change planning and adaptation is imperative for mitigating heat-related mortality risk across the region. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Variation and seasonal patterns of suicide mortality in Finland and Sweden since the 1750s.

    Science.gov (United States)

    Holopainen, Jari; Helama, Samuli; Björkenstam, Charlotte; Partonen, Timo

    2013-11-01

    Suicide mortality varies in both the short and long term. Our study examines suicide mortality in Finland and Sweden from the 1750s until today. The aim of our study is to detect any seasonal peaks in suicide rates and examine their temporal evolution to suggest a mechanism that may explain such peaks. We acquired the study material from the Finnish and Swedish cause of death statistics (257,341 deaths by suicide) and the relevant population gender structure data. We then separately calculated the annual male and female suicide rates per 100,000 inhabitants. We analysed the suicide peaks, calculating factors of proportionality for the available data by dividing the suicide rates in the peak months (May and October) by the annual suicide rates. Suicide rates in Finland and Sweden peak twice a year. Both men and women in both countries most often commit suicide in May. There is another peak in October, with the exception of Finnish men. These suicide peaks coincide with a temperature increase in May and the biggest annual drop in temperature in October. We also observed a monotonic long-term change in the Swedish statistics, but not in the Finnish data. Our hypothesis is that seasonal variation in suicide rates may be caused by abrupt temperature changes twice a year that trigger the activity in brown adipose tissue and deepen depression. While the overall suicide mortality rates varied considerably, the monthly proportions in May did not. This finding suggests a routine factor underlying the spring peak in suicide mortality.

  20. Intensified Arctic warming under greenhouse warming by vegetation–atmosphere–sea ice interaction

    International Nuclear Information System (INIS)

    Jeong, Jee-Hoon; Kug, Jong-Seong; Linderholm, Hans W; Chen, Deliang; Kim, Baek-Min; Jun, Sang-Yoon

    2014-01-01

    Observations and modeling studies indicate that enhanced vegetation activities over high latitudes under an elevated CO 2 concentration accelerate surface warming by reducing the surface albedo. In this study, we suggest that vegetation-atmosphere-sea ice interactions over high latitudes can induce an additional amplification of Arctic warming. Our hypothesis is tested by a series of coupled vegetation-climate model simulations under 2xCO 2 environments. The increased vegetation activities over high latitudes under a 2xCO 2 condition induce additional surface warming and turbulent heat fluxes to the atmosphere, which are transported to the Arctic through the atmosphere. This causes additional sea-ice melting and upper-ocean warming during the warm season. As a consequence, the Arctic and high-latitude warming is greatly amplified in the following winter and spring, which further promotes vegetation activities the following year. We conclude that the vegetation-atmosphere-sea ice interaction gives rise to additional positive feedback of the Arctic amplification. (letter)

  1. Suicide Mortality Among Retired National Football League Players Who Played 5 or More Seasons.

    Science.gov (United States)

    Lehman, Everett J; Hein, Misty J; Gersic, Christine M

    2016-10-01

    There is current disagreement in the scientific literature about the relationship between playing football and suicide risk, particularly among professional players in the National Football League (NFL). While some research indicates players are at high risk of football-related concussions, which may lead to chronic traumatic encephalopathy and suicide, other research finds such a connection to be speculative and unsupported by methodologically sound research. To compare the suicide mortality of a cohort of NFL players to what would be expected in the general population of the United States. Cohort study; Level of evidence, 3. A cohort of 3439 NFL players with at least 5 credited playing seasons between 1959 and 1988 was assembled for statistical analysis. The vital status for this cohort was updated through 2013. Standardized mortality ratios (SMRs), the ratio of observed deaths to expected deaths, and 95% CIs were computed for the cohort; 95% CIs that excluded unity were considered statistically significant. For internal comparison purposes, standardized rate ratios were calculated to compare mortality results between players stratified into speed and nonspeed position types. Suicide among this cohort of professional football players was significantly less than would be expected in comparison with the United States population (SMR = 0.47; 95% CI, 0.24-0.82). There were no significant differences in suicide mortality between speed and nonspeed position players. There is no indication of elevated suicide risk in this cohort of professional football players with 5 or more credited seasons of play. Because of the unique nature of this cohort, these study results may not be applicable to professional football players who played fewer than 5 years or to college or high school players. © 2016 The Author(s).

  2. SEASONAL INCIDENCE AND AGE-RELATED MORBIDITY AND MORTALITY OF VARICELLA IN KERALA

    Directory of Open Access Journals (Sweden)

    Junais Koleri

    2017-01-01

    Full Text Available BACKGROUND As the incidence of varicella in children is decreasing, the infection rate in the adults is on the rise. This study attempts to identify the all-cause-mortality and morbidity rate of varicella in adults and also the seasonal pattern of varicella infection. MATERIALS AND METHODS Varicella is diagnosed clinically. The data is recovered from case records of all the patients admitted at Government Medical College, Kozhikode, continuously over 2007 to 2012. RESULTS 640 patients were admitted with most of the cases in the age group of 20 to 40. 40% of the population belonged to above fifty years. The mean duration of hospitalisation was 21.5 days in elderly against 5 days in young patients. The mortality rate was also high in elderly (10.8% vs. 4% The varicella epidemics peak towards January to April. CONCLUSION The duration of hospital admission and the all-cause-mortality is much high in elderly population with varicella. Hence, there should be attempts to vaccinate the susceptible elderly population. The disease peaks towards January to April; hence, resources can be planned accordingly for proper utilisation.

  3. Warming and provenance limit tree recruitment across and beyond the elevation range of subalpine forest.

    Science.gov (United States)

    Kueppers, Lara M; Conlisk, Erin; Castanha, Cristina; Moyes, Andrew B; Germino, Matthew J; de Valpine, Perry; Torn, Margaret S; Mitton, Jeffry B

    2017-06-01

    Climate niche models project that subalpine forest ranges will extend upslope with climate warming. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, but raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased season-average soil moisture similarly across sites. Contrary to expectations, warming reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. Warming reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free season alleviated some negative effects of warming, indicating that warming exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to warming across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with warming, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The lower

  4. EFFECT OF PRE-COOLING ON REPEAT-SPRINT PERFORMANCE IN SEASONALLY ACCLIMATISED MALES DURING AN OUTDOOR SIMULATED TEAM-SPORT PROTOCOL IN WARM CONDITIONS

    Directory of Open Access Journals (Sweden)

    Carly J. Brade

    2013-09-01

    Full Text Available Whether precooling is beneficial for exercise performance in warm climates when heat acclimatised is unclear. The purpose of this study was to determine the effect of precooling on repeat-sprint performance during a simulated team-sport circuit performed outdoors in warm, dry field conditions in seasonally acclimatised males (n = 10. They performed two trials, one with precooling (PC; ice slushy and cooling jacket and another without (CONT. Trials began with a 30-min baseline/cooling period followed by an 80 min repeat-sprint protocol, comprising 4 x 20-min quarters, with 2 x 5-min quarter breaks and a 10-min half-time recovery/cooling period. A clear and substantial (negative; PC slower effect was recorded for first quarter circuit time. Clear and trivial effects were recorded for overall circuit time, third and fourth quarter sprint times and fourth quarter best sprint time, otherwise unclear and trivial effects were recorded for remaining performance variables. Core temperature was moderately lower (Cohen's d=0.67; 90% CL=-1.27, 0.23 in PC at the end of the precooling period and quarter 1. No differences were found for mean skin temperature, heart rate, thermal sensation, or rating of perceived exertion, however, moderate Cohen's d effect sizes suggested a greater sweat loss in PC compared with CONT. In conclusion, repeat- sprint performance was neither clearly nor substantially improved in seasonally acclimatised players by using a combination of internal and external cooling methods prior to and during exercise performed in the field in warm, dry conditions. Of practical importance, precooling appears unnecessary for repeat-sprint performance if athletes are seasonally acclimatised or artificially acclimated to heat, as it provides no additional benefit

  5. Associations between ambient air pollution and daily mortality among persons with congestive heart failure

    International Nuclear Information System (INIS)

    Goldberg, Mark S.; Burnett, Richard T.; Valois, M.-F.; Flegel, Kenneth; Bailar III, John C.; Brook, Jeffrey; Vincent Renaud; Radon, Katja

    2003-01-01

    We conducted a mortality time series study to investigate the association between daily mortality for congestive heart failure (CHF), and dail concentrations of particles and gaseous pollutants in the ambient air o Montreal, Quebec, during the period 1984-1993. In addition, using data fro the universal Quebec Health Insurance Plan, we identified individuals ≥6 years of age who, one year before death, had a diagnosis of CHF. Fixed-sit air pollution monitors in Montreal provided daily mean levels of pollutants We regressed the logarithm of daily counts of mortality on the daily mean levels of each pollutant, after accounting for seasonal and subseasonal fluctuations in the mortality time series, non-Poisson dispersion, weather variables, and other gaseous and particle pollutants. Using cause of deat information, we did not find any associations between daily mortality for CH and any air pollutants. The analyses of CHF defined from the medical record showed positive associations with coefficient of haze, the extinction coefficient, SO 2 , and NO 2 . For example, the mean percent increase in dail mortality for an increase in the coefficient of haze across the interquartile range was 4.32% (95% CI: 0.95-7.80%) and for NO 2 it was 4.08% (95% CI 0.59-7.68%). These effects were generally higher in the warm season

  6. Season of prescribed burn in ponderosa pine forests in eastern Oregon: impact on pine mortality.

    Science.gov (United States)

    Walter G. Thies; Douglas J. Westlind; Mark. Loewen

    2005-01-01

    A study of the effects of season of prescribed burn on tree mortality was established in mixed-age ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at the south end of the Blue Mountains near Burns, Oregon. Each of six previously thinned stands was subdivided into three experimental units and one of three treatments was randomly assigned to each:...

  7. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    Science.gov (United States)

    Tsyganov, Andrey N; Aerts, Rien; Nijs, Ivan; Cornelissen, Johannes H C; Beyens, Louis

    2012-05-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming, winter snow addition solely and winter snow addition together with spring warming on testate amoeba assemblages after eight years of experimental field climate manipulations. All manipulations were accomplished using open top chambers in a dry blanket bog located in the sub-Arctic (Abisko, Sweden). We estimated sensitivity of abundance, diversity and assemblage structure of living and empty shell assemblages of testate amoebae in the living and decaying layers of Sphagnum. Our results show that, in a sub-arctic climate, testate amoebae are more sensitive to climate changes in the growing season than in winter. Summer warming reduced species richness and shifted assemblage composition towards predominance of xerophilous species for the living and empty shell assemblages in both layers. The higher soil temperatures during the growing season also decreased abundance of empty shells in both layers hinting at a possible increase in their decomposition rates. Thus, although possible effects of climate changes on preservation of empty shells should always be taken into account, species diversity and structure of testate amoeba assemblages in dry subarctic bogs are sensitive proxies for climatic changes during the growing season. Copyright © 2011 Elsevier GmbH. All rights reserved.

  8. Forage yield and nitrogen nutrition dynamics of warm-season native forage genotypes under two shading levels and in full sunlight

    OpenAIRE

    Barro,Raquel Santiago; Varella,Alexandre Costa; Lemaire,Gilles; Medeiros,Renato Borges de; Saibro,João Carlos de; Nabinger,Carlos; Bangel,Felipe Villamil; Carassai,Igor Justin

    2012-01-01

    The successful achievement of a highly productive understorey pasture in silvopastoral systems depends on the use of well-adapted forage genotypes, showing good agronomic performance and persistence under shading and grazing. In this study, the herbage dry matter yield (DMY) and nitrogen nutrition dynamics were determined in three native warm-season grasses (Paspalum regnellii, Paspalum dilatatum and Paspalum notatum) and a forage legume (Arachis pintoi) under two shading levels compared with...

  9. Declining impacts of hot spells on mortality in the Czech Republic: adaptation to climate change?

    Science.gov (United States)

    Kysely, Jan; Plavcova, Eva

    2010-05-01

    Extreme temperature events have pronounced negative impacts on ecosystems and society, including human health effects. The study examines temporal changes in mortality associated with spells of large positive temperature anomalies (hot spells) in the population of the Czech Republic (central Europe) during 1986-2006. Declining trends in the mortality impacts are found in summer as well as in transition seasons, in spite of rising temperature trends (warming by 1.4 deg. C in summer over the 21-year period). The finding remains unchanged if possible confounding effects of within-season acclimatization to heat and the mortality displacement effect are taken into account. Recent positive socio-economic development, following the collapse of communism in central and eastern Europe in 1989, and better public awareness of heat-related risks are likely the primary causes of the declining vulnerability. The results suggest that climate change may have relatively little influence on heat-related deaths, since changes in other factors that influence vulnerability of the population are dominant instead of temperature trends. It is essential to better understand the observed non-stationarity of the temperature-mortality relationship and the role of adaptation and its limits, both physiological and technological, and to address associated uncertainties in studies dealing with climate change projections of temperature-related mortality.

  10. Morbidity, Mortality, and Seasonality of Influenza Hospitalizations in Egypt, November 2007-November 2014

    Science.gov (United States)

    Kandeel, Amr; Labib, Manal; Said, Mayar; El-Refai, Samir; El-Gohari, Amani; Talaat, Maha

    2016-01-01

    Background Influenza typically comprises a substantial portion of acute respiratory infections, a leading cause of mortality worldwide. However, influenza epidemiology data are lacking in Egypt. We describe seven years of Egypt’s influenza hospitalizations from a multi-site influenza surveillance system. Methods Syndromic case definitions identified individuals with severe acute respiratory infection (SARI) admitted to eight hospitals in Egypt. Standardized demographic and clinical data were collected. Nasopharyngeal and oropharyngeal swabs were tested for influenza using real-time reverse transcription polymerase chain reaction and typed as influenza A or B, and influenza A specimens subtyped. Results From November 2007–November 2014, 2,936/17,441 (17%) SARI cases were influenza-positive. Influenza-positive patients were more likely to be older, female, pregnant, and have chronic condition(s) (all p<0.05). Among them, 53 (2%) died, and death was associated with older age, five or more days from symptom onset to hospitalization, chronic condition(s), and influenza A (all p<0.05). An annual seasonal influenza pattern occurred from July–June. Each season, the proportion of the season’s influenza-positive cases peaked during November–May (19–41%). Conclusions In Egypt, influenza causes considerable morbidity and mortality and influenza SARI hospitalization patterns mirror those of the Northern Hemisphere. Additional assessment of influenza epidemiology in Egypt may better guide disease control activities and vaccine policy. PMID:27607330

  11. Warming slowdown over the Tibetan plateau in recent decades

    Science.gov (United States)

    Liu, Yaojie; Zhang, Yangjian; Zhu, Juntao; Huang, Ke; Zu, Jiaxing; Chen, Ning; Cong, Nan; Stegehuis, Annemiek Irene

    2018-03-01

    As the recent global warming hiatus and the warming on high elevations are attracting worldwide attention, this study examined the robustness of the warming slowdown over the Tibetan plateau (TP) and its related driving forces. By integrating multiple-source data from 1982 to 2015 and using trend analysis, we found that the mean temperature (T mean), maximum temperature (T max) and minimum temperature (T min) showed a slowdown of the warming trend around 1998, during the period of the global warming hiatus. This was found over both the growing season (GS) and non-growing season (NGS) and suggested a robust warming hiatus over the TP. Due to the differences in trends of T max and T min, the trend of diurnal temperature range (DTR) also shifted after 1998, especially during the GS temperature. The warming rate was spatially heterogeneous. The northern TP (NTP) experienced more warming than the southern TP (STP) in all seasons from 1982 to 1998, while the pattern was reversed in the period from 1998 to 2015. Water vapour was found to be the main driving force for the trend in T mean and T min by influencing downward long wave radiation. Sunshine duration was the main driving force behind the trend in T max and DTR through a change in downward shortwave radiation that altered the energy source of daytime temperature. Water vapour was the major driving force for temperature change over the NTP, while over the STP, sunshine duration dominated the temperature trend.

  12. Mortality burden of the 2009 A/H1N1 influenza pandemic in France: comparison to seasonal influenza and the A/H3N2 pandemic.

    Directory of Open Access Journals (Sweden)

    Magali Lemaitre

    Full Text Available BACKGROUND: The mortality burden of the 2009 A/H1N1 pandemic remains unclear in many countries due to delays in reporting of death statistics. We estimate the age- and cause-specific excess mortality impact of the pandemic in France, relative to that of other countries and past epidemic and pandemic seasons. METHODS: We applied Serfling and Poisson excess mortality approaches to model weekly age- and cause-specific mortality rates from June 1969 through May 2010 in France. Indicators of influenza activity, time trends, and seasonal terms were included in the models. We also reviewed the literature for country-specific estimates of 2009 pandemic excess mortality rates to characterize geographical differences in the burden of this pandemic. RESULTS: The 2009 A/H1N1 pandemic was associated with 1.0 (95% Confidence Intervals (CI 0.2-1.9 excess respiratory deaths per 100,000 population in France, compared to rates per 100,000 of 44 (95% CI 43-45 for the A/H3N2 pandemic and 2.9 (95% CI 2.3-3.7 for average inter-pandemic seasons. The 2009 A/H1N1 pandemic had a 10.6-fold higher impact than inter-pandemic seasons in people aged 5-24 years and 3.8-fold lower impact among people over 65 years. CONCLUSIONS: The 2009 pandemic in France had low mortality impact in most age groups, relative to past influenza seasons, except in school-age children and young adults. The historical A/H3N2 pandemic was associated with much larger mortality impact than the 2009 pandemic, across all age groups and outcomes. Our 2009 pandemic excess mortality estimates for France fall within the range of previous estimates for high-income regions. Based on the analysis of several mortality outcomes and comparison with laboratory-confirmed 2009/H1N1 deaths, we conclude that cardio-respiratory and all-cause mortality lack precision to accurately measure the impact of this pandemic in high-income settings and that use of more specific mortality outcomes is important to obtain reliable

  13. The Effect of Passive Design Strategies on Thermal Performance of Female Secondary School Buildings during Warm Season in Hot Dry Climate

    Directory of Open Access Journals (Sweden)

    Sahar eZahiri

    2016-03-01

    Full Text Available This paper describes a series of field studies and simulation analysis to improve the thermal performance of school buildings in the city of Tehran in Iran during warm season. The field studies used on-site measurement and questionnaire-based survey in the warm spring season in a typical female secondary school building. The on-site monitoring assessed the indoor air temperature and humidity levels of six classrooms while the occupants completed questionnaires covering their thermal sensations and thermal preferences. Moreover, thermal simulation analysis was also carried out to evaluate and improve the thermal performance of the classrooms based on the students’ thermal requirements and passive design strategies. In this study, the environmental design guidelines for female secondary school buildings were introduced for the hot and dry climate of Tehran, using passive design strategies. The study shows that the application of passive design strategies including south and south-east orientation, 10cm thermal insulation in wall and 5cm in the roof, and the combination of 30cm side fins and overhangs as a solar shading devices, as well as all-day ventilation strategy and the use of thermal mass materials with 25cm-30cm thickness, has considerable impact on indoor air temperatures in warm season in Tehran and keeps the indoor environment in an acceptable thermal condition. The results of the field studies also indicated that most of the occupants found their thermal environment not to be comfortable and the simulation results showed that passive design techniques had a significant influence on the indoor air temperature and can keep it in an acceptable range based on the female students’ thermal requirement. Therefore, in order to enhance the indoor environment and to increase the learning performance of the students, it is necessary to use the appropriate passive design strategies, which also reduce the need for mechanical systems and

  14. Specificity Responses of Grasshoppers in Temperate Grasslands to Diel Asymmetric Warming

    Science.gov (United States)

    Wu, Tingjuan; Hao, Shuguang; Sun, Osbert Jianxin; Kang, Le

    2012-01-01

    Background Global warming is characterized by not only an increase in the daily mean temperature, but also a diel asymmetric pattern. However, most of the current studies on climate change have only concerned with the mean values of the warming trend. Although many studies have been conducted concerning the responses of insects to climate change, studies that address the issue of diel asymmetric warming under field conditions are not found in the literature. Methodology/Principal Findings We conducted a field climate manipulative experiment and investigated developmental and demographic responses to diel asymmetric warming in three grasshopper species (an early-season species Dasyhippus barbipes, a mid-season species Oedaleus asiaticus, and a late-season species Chorthippus fallax). It was found that warming generally advanced the development of eggs and nymphs, but had no apparent impacts on the hatching rate of eggs, the emergence rate of nymphs and the survival and fecundity of adults in all the three species. Nighttime warming was more effective in advancing egg development than the daytime warming. The emergence time of adults was differentially advanced by warming in the three species; it was advanced by 5.64 days in C. fallax, 3.55 days in O. asiaticus, and 1.96 days in D. barbipes. This phenological advancement was associated with increases in the effective GDDs accumulation. Conclusions/Significance Results in this study indicate that the responses of the three grasshopper species to warming are influenced by several factors, including species traits, developmental stage, and the thermal sensitivity of the species. Moreover, species with diapausing eggs are less responsive to changes in temperature regimes, suggesting that development of diapausing eggs is a protective mechanism in early-season grasshopper for avoiding the risk of pre-winter hatching. Our results highlight the need to consider the complex relationships between climate change and

  15. Intake, digestibility, and nitrogen retention by sheep supplemented with warm-season legume haylages or soybean meal.

    Science.gov (United States)

    Foster, J L; Adesogan, A T; Carter, J N; Blount, A R; Myer, R O; Phatak, S C

    2009-09-01

    The high cost of commercial supplements necessitates evaluation of alternatives for ruminant livestock fed poor quality warm-season grasses. This study determined how supplementing bahiagrass haylage (Paspalum notatum Flügge cv. Tifton 9) with soybean [Glycine max (L.) Merr.] meal or warm-season legume haylages affected the performance of lambs. Forty-two Dorper x Katadhin lambs (27.5 +/- 5 kg) were fed for ad libitum intake of bahiagrass haylage (67.8% NDF, 9.6% CP) alone (control) or supplemented with soybean meal (18.8% NDF, 51.4% CP) or haylages of annual peanut [Arachis hypogaea (L.) cv. Florida MDR98; 39.6% NDF, 18.7% CP], cowpea [Vigna unguiculata (L.) Walp. cv. Iron clay; 44.1% NDF, 16.0% CP], perennial peanut (Arachis glabrata Benth. cv. Florigraze; 40.0% NDF, 15.8% CP), or pigeonpea [Cajanus cajan (L.) Millsp. cv. GA-2; 65.0% NDF, 13.7% CP]. Haylages were harvested at the optimal maturity for maximizing yield and nutritive value, wilted to 45% DM, baled, wrapped in polyethylene plastic, and ensiled for 180 d. Legumes were fed at 50% of the dietary DM, and soybean meal was fed at 8% of the dietary DM to match the average CP concentration (12.8%) of legume haylage-supplemented diets. Lambs were fed each diet for a 14-d adaptation period and a 7-d data collection period. Each diet was fed to 7 lambs in period 1 and 4 lambs in period 2. Pigeonpea haylage supplementation decreased (P haylages increased (P haylage, all supplements increased (P haylage supplementation, but unaffected (P = 0.05) by other supplements. Efficiency of microbial protein synthesis was unaffected (P = 0.05) by diet. Ruminal ammonia concentration was increased (P = 0.01) by all supplements, but only soybean meal and annual peanut haylage increased (P haylages are promising protein supplements for growing lambs.

  16. Season exerts differential effects of ocean acidification and warming on growth and carbon metabolism of the seaweed Fucus vesiculosus in the western Baltic Sea

    Directory of Open Access Journals (Sweden)

    Angelika eGraiff

    2015-12-01

    Full Text Available Warming and acidification of the oceans as a consequence of increasing CO2-concentrations occur at large scales. Numerous studies have shown the impact of single stressors on individual species. However, studies on the combined effect of multiple stressors on a multi-species assemblage, which is ecologically much more realistic and relevant, are still scarce. Therefore, we orthogonally crossed the two factors warming and acidification in mesocosm experiments and studied their single and combined impact on the brown alga Fucus vesiculosus associated with its natural community (epiphytes and mesograzers in the Baltic Sea in all seasons (from April 2013 to April 2014. We superimposed our treatment factors onto the natural fluctuations of all environmental variables present in the Benthocosms in so-called delta-treatments. Thereby we compared the physiological responses of F. vesiculosus (growth and metabolites to the single and combined effects of natural Kiel Fjord temperatures and pCO2 conditions with a 5 °C temperature increase and/or pCO2 increase treatment (1100 ppm in the headspace above the mesocosms. Responses were also related to the factor photoperiod which changes over the course of the year. Our results demonstrate complex seasonal pattern. Elevated pCO2 positively affected growth of F. vesiculosus alone and/or interactively with warming. The response direction (additive, synergistic or antagonistic, however, depended on season and daylength. The effects were most obvious when plants were actively growing during spring and early summer. Our study revealed for the first time that it is crucial to always consider the impact of variable environmental conditions throughout all seasons. In summary, our study indicates that in future F. vesiculosus will be more affected by detrimental summer heat-waves than by ocean acidification although the latter consequently enhances growth throughout the year. The mainly negative influence of rising

  17. Dynamic response of wind turbine towers in warm permafrost

    Institute of Scientific and Technical Information of China (English)

    Benjamin Still; ZhaoHui Joey Yang; Simon Evans; FuJun Niu

    2014-01-01

    Wind is a great source of renewable energy in western Alaska. Consistent winds blow across the barren tundra underlain by warm permafrost in the winter season, when the energy demand is the highest. Foundation engineering in warm permafrost has always been a challenge in wind energy development. Degrading warm permafrost poses engineering issues to design, construction, and operation of wind turbines. This paper describes the foundation design of a wind turbine built in western Alaska. It presents a sys-tem for response monitoring and load assessment, and data collected from September 2013 to March 2014. The dynamic proper-ties are assessed based on the monitoring data, and seasonal changes in the dynamic properties of the turbine tower-foundation system and likely resonance between the spinning blades and the tower structure are discussed. These analyses of a wind turbine in warm permafrost are valuable for designing or retrofitting of foundations in warm permafrost.

  18. Experimental winter warming modifies thermal performance and primes acorn ants for warm weather

    DEFF Research Database (Denmark)

    MacLean, Heidi J.; Penick, Clint A.; Dunn, Robert R.

    2017-01-01

    The frequency of warm winter days is increasing under global climate change, but how organisms respond to warmer winters is not well understood. Most studies focus on growing season responses to warming. Locomotor performance is often highly sensitive to temperature, and can determine fitness...... outcomes through a variety of mechanisms including resource acquisition and predator escape. As a consequence, locomotor performance, and its impacts on fitness, may be strongly affected by winter warming in winter-active species. Here we use the acorn ant, Temnothorax curvispinosus, to explore how thermal...... performance (temperature-driven plasticity) in running speed is influenced by experimental winter warming of 3–5 °C above ambient in a field setting. We used running speed as a measure of performance as it is a common locomotor trait that influences acquisition of nest sites and food in acorn ants...

  19. A Case-Only Study of Vulnerability to Heat Wave-Related Mortality in New York City (2000-2011).

    Science.gov (United States)

    Madrigano, Jaime; Ito, Kazuhiko; Johnson, Sarah; Kinney, Patrick L; Matte, Thomas

    2015-07-01

    As a result of climate change, the frequency of extreme temperature events is expected to increase, and such events are associated with increased morbidity and mortality. Vulnerability patterns, and corresponding adaptation strategies, are most usefully conceptualized at a local level. We used a case-only analysis to examine subject and neighborhood characteristics that modified the association between heat waves and mortality. All deaths of New York City residents from 2000 through 2011 were included in this analysis. Meteorological data were obtained from the National Climatic Data Center. Modifying characteristics were obtained from the death record and geographic data sets. A total of 234,042 adult deaths occurred during the warm season of our study period. Compared with other warm-season days, deaths during heat waves were more likely to occur in black (non-Hispanic) individuals than other race/ethnicities [odds ratio (OR) = 1.08; 95% CI: 1.03, 1.12], more likely to occur at home than in institutions and hospital settings (OR = 1.11; 95% CI: 1.06, 1.16), and more likely among those living in census tracts that received greater public assistance (OR = 1.05; 95% CI: 1.01, 1.09). Finally, deaths during heat waves were more likely among residents in areas of the city with higher relative daytime summer surface temperature and less likely among residents living in areas with more green space. Mortality during heat waves varies widely within a city. Understanding which individuals and neighborhoods are most vulnerable can help guide local preparedness efforts.

  20. Basin-Wide Amazon Forest Tree Mortality From a Large 2005 Storm

    Science.gov (United States)

    Negron Juarez, R. I.; Chambers, J. Q.; Guimaraes, G.; Zeng, H.; Raupp, C.; Marra, D. M.; Ribeiro, G.; Saatchi, S. S.; Higuchi, N.

    2010-12-01

    Blowdowns are a recurrent characteristic of Amazon forests and are produced, among others, by squall lines. Squall lines are aligned clusters (typical length of 1000 km, width of 200 km) of deep convective cells that produce heavy rainfall during the dry season and significant rainfall during the wet season. These squall lines (accompanied by intense downbursts from convective cells) have been associated with large blowdowns characterized by uprooted, snapped trees, and trees being dragged down by other falling trees. Most squall lines in Amazonia form along the northeastern coast of South America as sea breeze-induced instability lines and propagate inside the continent. They occur frequently (~4 times per month), and can reach the central and even extreme western parts of Amazonia. Squall lines can also be generated inside the Amazon and propagate toward the equator. In January 2005 a squall line propagated from south to north across the entire Amazon basin producing widespread forest tree mortality and contributed to the elevated mortality observed that year. Over the Manaus region (3.4 x104 km2), disturbed forest patches generated by the squall produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. The elevated mortality observed in the Central Amazon in 2005 is unlikely to be related to the 2005 Amazon drought since drought did not affect Central or Eastern Amazonia. Assuming a similar rate of forest mortality across the basin, the squall line could have potentially produced tree mortality estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. This vulnerability is likely to increase in a warming climate with models projecting an increase in storm intensity.

  1. Terrestrial carbon cycle affected by non-uniform climate warming

    International Nuclear Information System (INIS)

    Jianyang Xia; Yiqi Luo; Jiquan Chen; Shilong Piao; Ciais, Philippe; Shiqiang Wan

    2014-01-01

    Feedbacks between the terrestrial carbon cycle and climate change could affect many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The rate of climate warming varies on diurnal and seasonal timescales. A synthesis of global air temperature data reveals a greater rate of warming in winter than in summer in northern mid and high latitudes, and the inverse pattern in some tropical regions. The data also reveal a decline in the diurnal temperature range over 51% of the global land area and an increase over only 13%, because night-time temperatures in most locations have risen faster than daytime temperatures. Analyses of satellite data, model simulations and in situ observations suggest that the impact of seasonal warming varies between regions. For example, spring warming has largely stimulated ecosystem productivity at latitudes between 30 degrees and 90 degrees N, but suppressed productivity in other regions. Contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. We argue that ascertaining the effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research. (authors)

  2. Seasonal timing in a warming world : plasticity of seasonal timing of growth and reproduction

    OpenAIRE

    Salis, L.

    2015-01-01

    In seasonal environments the timing of various biological processes is crucial for growth, survival and reproductive success of an individual. Nowadays, rapid large-scale climate change is altering species’ seasonal timing (phenology) in many eco¬systems. In this thesis Lucia Salis focuses on the study of seasonal timing in the food chain of the oak-winter moth-great tit. As temperature increased over the last decades, both phenologies of the host plant, the oak, and the herbivorous insect, t...

  3. Dynamics of Necrophagous Insect and Tissue Bacteria for Postmortem Interval Estimation During the Warm Season in Romania.

    Science.gov (United States)

    Iancu, Lavinia; Sahlean, Tiberiu; Purcarea, Cristina

    2016-01-01

    The estimation of postmortem interval (PMI) is affected by several factors including the cause of death, the place where the body lay after death, and the weather conditions during decomposition. Given the climatic differences among biogeographic locations, the understanding of necrophagous insect species biology and ecology is required when estimating PMI. The current experimental model was developed in Romania during the warm season in an outdoor location. The aim of the study was to identify the necrophagous insect species diversity and dynamics, and to detect the bacterial species present during decomposition in order to determine if their presence or incidence timing could be useful to estimate PMI. The decomposition process of domestic swine carcasses was monitored throughout a 14-wk period (10 July-10 October 2013), along with a daily record of meteorological parameters. The chronological succession of necrophagous entomofauna comprised nine Diptera species, with the dominant presence of Chrysomya albiceps (Wiedemann 1819) (Calliphoridae), while only two Coleoptera species were identified, Dermestes undulatus (L. 1758) and Creophilus maxillosus Brahm 1970. The bacterial diversity and dynamics from the mouth and rectum tissues, and third-instar dipteran larvae were identified using denaturing gradient gel electrophoresis analysis and sequencing of bacterial 16S rRNA gene fragments. Throughout the decomposition process, two main bacterial chronological groups were differentiated, represented by Firmicutes and Gammaproteobacteria. Twenty-six taxa from the rectal cavity and 22 from the mouth cavity were identified, with the dominant phylum in both these cavities corresponding to Firmicutes. The present data strengthen the postmortem entomological and microbial information for the warm season in this temperate-continental area, as well as the role of microbes in carcass decomposition. © The Authors 2015. Published by Oxford University Press on behalf of

  4. Seasonal variation and trends in stroke hospitalizations and mortality in a South American community hospital.

    Science.gov (United States)

    Díaz, Alejandro; Gerschcovich, Eliana Roldan; Díaz, Adriana A; Antía, Fabiana; Gonorazky, Sergio

    2013-10-01

    Numerous studies have reported the presence of temporal variations in biological processes. Seasonal variation (SV) in stroke has been widely studied, but little data have been published on this phenomenon in the Southern Hemisphere, and there have been no studies reported from Argentina. The goals of the present study were to describe the SV of admissions and deaths for stroke and examine trends in stroke morbidity and mortality over a 3-year period in a community hospital in Argentina. Hospital discharge reports from the electronic database of vital statistics between 1999 and 2001 were examined retrospectively. Patients who had a main discharge diagnosis of stroke (ischemic or hemorrhagic) or cerebrovascular accident (International Classification of Diseases, Ninth Revision codes 431, 432, 434, and 436) were selected. The study sample included 1382 hospitalizations by stroke (3.5% of all admissions). In-hospital mortality demonstrated a winter peak (25.5% vs 17% in summer; P = .001). The crude seasonal stroke attack rate (ischemic and hemorrhagic) was highest in winter (164 per 100,000 population; 95% CI, 159-169 per 100,000) and lowest in summer (124 per 100,000; 95% CI, 120-127 per 100,000; P = .008). Stroke admissions followed a seasonal pattern, with a winter-spring predominance (P = .008). Our data indicate a clear SV in stroke deaths and admissions in this region of Argentina. The existence of SV in stroke raises a different hypothesis about the rationale of HF admissions and provides information for the organization of care and resource allocation. Copyright © 2013 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  5. Seasonal variation in the acute effect of particulate air pollution on mortality in the China Air Pollution and Health Effects Study (CAPES)

    Science.gov (United States)

    Chen, Renjie; Peng, Roger D.; Meng, Xia; Zhou, Zhijun; Chen, Bingheng; Kan, Haidong

    2013-01-01

    Epidemiological findings concerning the seasonal variation in the acute effect of particulate matter (PM) are inconsistent. We investigated the seasonality in the association between PM with an aerodynamic diameter of less than 10 μm (PM10) and daily mortality in 17 Chinese cities. We fitted the “main” time-series model after adjustment for time-varying confounders using smooth functions with natural splines. We established a “seasonal” model to obtain the season-specific effect estimates of PM10, and a “harmonic” model to show the seasonal pattern that allows PM10 effects to vary smoothly with the day in a year. At the national level, a 10 μg/m3 increase in the two-day moving average concentrations (lag 01) of PM10 was associated with 0.45% [95% posterior interval (PI), 0.15% to 0.76%], 0.17% (95% PI, −0.09% to 0.43%), 0.55% (95% PI, 0.15% to 0.96%) and 0.25% (95%PI, −0.05% to 0.56%) increases in total mortality for winter, spring, summer and fall, respectively. For the smoothly-varying plots of seasonality, we identified a two-peak pattern in winter and summer. The observed seasonal pattern was generally insensitive to model specifications. Our analyses suggest that the acute effect of particulate air pollution could vary by seasons with the largest effect in winter and summer in China. To our knowledge, this is the first multicity study in developing countries to analyze the seasonal variations of PM-related health effects. PMID:23500824

  6. Corresponding Relation between Warm Season Precipitation Extremes and Surface Air Temperature in South China

    Institute of Scientific and Technical Information of China (English)

    SUN; Wei; LI; Jian; YU; Ru-Cong

    2013-01-01

    Hourly data of 42 rain gauges over South China during 1966–2005 were used to analyze the corresponding relation between precipitation extremes and surface air temperature in the warm season(May to October).The results show that below 25℃,both daily and hourly precipitation extremes in South China increase with rising temperature.More extreme events transit to the two-time Clausius-Clapeyron(CC)relationship at lower temperatures.Daily as well as hourly precipitation extremes have a decreasing tendency nearly above 25℃,among which the decrease of hourly extremes is much more significant.In order to investigate the efects of rainfall durations,hourly precipitation extremes are presented by short duration and long duration precipitation,respectively.Results show that the dramatic decrease of hourly rainfall intensities above 25℃ is mainly caused by short duration precipitation,and long duration precipitation extremes rarely occur in South China when surface air temperature surpasses 28℃.

  7. Temperature-mortality relationship in dairy cattle in France based on an iso-hygro-thermal partition of the territory

    Science.gov (United States)

    Morignat, Eric; Gay, Emilie; Vinard, Jean-Luc; Calavas, Didier; Hénaux, Viviane

    2017-11-01

    The issue of global warming and more specifically its health impact on populations is increasingly concerning. The aim of our study was to evaluate the impact of temperature on dairy cattle mortality in France during the warm season (April-August). We therefore devised and implemented a spatial partitioning method to divide France into areas in which weather conditions were homogeneous, combining a multiple factor analysis with a clustering method using both weather and spatial data. We then used time-series regressions (2001-2008) to model the relationship between temperature humidity index (an index representing the temperature corrected by the relative humidity) and dairy cattle mortality within these areas. We found a significant effect of heat on dairy cattle mortality, but also an effect of cooler temperatures (to a lesser extent in some areas), which leads to a U-shaped relationship in the studied areas. Our partitioning approach based on weather criteria, associated with classic clustering methods, may contribute to better estimating temperature effects, a critical issue for animal health and welfare. Beyond the interest of its use in animal health, this approach can also be of interest in several situations in the frame of human health.

  8. Seasonal Variation in Solar Ultra Violet Radiation and Early Mortality in Extremely Preterm Infants.

    Science.gov (United States)

    Salas, Ariel A; Smith, Kelly A; Rodgers, Mackenzie D; Phillips, Vivien; Ambalavanan, Namasivayam

    2015-11-01

    Vitamin D production during pregnancy promotes fetal lung development, a major determinant of infant survival after preterm birth. Because vitamin D synthesis in humans is regulated by solar ultraviolet B (UVB) radiation, we hypothesized that seasonal variation in solar UVB doses during fetal development would be associated with variation in neonatal mortality rates. This cohort study included infants born alive with gestational age (GA) between 23 and 28 weeks gestation admitted to a neonatal unit between 1996 and 2010. Three infant cohort groups were defined according to increasing intensities of solar UVB doses at 17 and 22 weeks gestation. The primary outcome was death during the first 28 days after birth. Outcome data of 2,319 infants were analyzed. Mean birth weight was 830 ± 230 g and median gestational age was 26 weeks. Mortality rates were significantly different across groups (p = 0.04). High-intensity solar UVB doses were associated with lower mortality when compared with normal intensity solar UVB doses (hazard ratio: 0.70; 95% confidence interval: 0.54-0.91; p = 0.01). High-intensity solar UVB doses during fetal development seem to be associated with risk reduction of early mortality in preterm infants. Prospective studies are needed to validate these preliminary findings. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  9. Free boundary models for mosquito range movement driven by climate warming.

    Science.gov (United States)

    Bao, Wendi; Du, Yihong; Lin, Zhigui; Zhu, Huaiping

    2018-03-01

    As vectors, mosquitoes transmit numerous mosquito-borne diseases. Among the many factors affecting the distribution and density of mosquitoes, climate change and warming have been increasingly recognized as major ones. In this paper, we make use of three diffusive logistic models with free boundary in one space dimension to explore the impact of climate warming on the movement of mosquito range. First, a general model incorporating temperature change with location and time is introduced. In order to gain insights of the model, a simplified version of the model with the change of temperature depending only on location is analyzed theoretically, for which the dynamical behavior is completely determined and presented. The general model can be modified into a more realistic one of seasonal succession type, to take into account of the seasonal changes of mosquito movements during each year, where the general model applies only for the time period of the warm seasons of the year, and during the cold season, the mosquito range is fixed and the population is assumed to be in a hibernating status. For both the general model and the seasonal succession model, our numerical simulations indicate that the long-time dynamical behavior is qualitatively similar to the simplified model, and the effect of climate warming on the movement of mosquitoes can be easily captured. Moreover, our analysis reveals that hibernating enhances the chances of survival and successful spreading of the mosquitoes, but it slows down the spreading speed.

  10. Seasonal timing in a warming world : Plasticity of seasonal timing of growth and reproduction

    NARCIS (Netherlands)

    Salis, Lucia

    2015-01-01

    In seasonal environments the timing of various biological processes is crucial for growth, survival and reproductive success of an individual. Nowadays, rapid large-scale climate change is altering species’ seasonal timing (phenology) in many eco¬systems. In this thesis Lucia Salis focuses on the

  11. Seasonality in ocean microbial communities.

    Science.gov (United States)

    Giovannoni, Stephen J; Vergin, Kevin L

    2012-02-10

    Ocean warming occurs every year in seasonal cycles that can help us to understand long-term responses of plankton to climate change. Rhythmic seasonal patterns of microbial community turnover are revealed when high-resolution measurements of microbial plankton diversity are applied to samples collected in lengthy time series. Seasonal cycles in microbial plankton are complex, but the expansion of fixed ocean stations monitoring long-term change and the development of automated instrumentation are providing the time-series data needed to understand how these cycles vary across broad geographical scales. By accumulating data and using predictive modeling, we gain insights into changes that will occur as the ocean surface continues to warm and as the extent and duration of ocean stratification increase. These developments will enable marine scientists to predict changes in geochemical cycles mediated by microbial communities and to gauge their broader impacts.

  12. Mean surface fields of heat budget components over the warm pool in the Bay of Bengal during post-monsoon season

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.; Rao, D.P.; Rao, B.P.

    Andaman Islands and in the MT area there is an association between SST and Q n . But, off Sri Lanka warmer waters were noticed eventhough Q n was negative. This gives a clue that the role of advection plays a dominant role in the maintenance of SST.... Maintenance of warmwaters could be due to the transport of heat from North to South during post-monsoon season. Individual contributions from advection and air-sea fluxes towards SST would throw better light on the formation of warm pool in Bay of Bengal...

  13. Mass Mortality of Cassin's Auklets, Assessing the Impact of a Warming Ocean

    Science.gov (United States)

    Parrish, J.

    2016-02-01

    In Fall/Winter 2014-15, more than 100,000 Cassin's Auklets, Ptychoramphus aleuticus, washed ashore on U.S. West Coast beaches. A small-bodied, zooplanktivorous bird, Cassin's nest in colonies scattered along the Northeast Pacific coastline, with a particular concentration in the Scott Islands, northwest of Vancouver Island, BC where 80% of the world's population ( 3.5M) breeds. Standardized, effort-controlled beach surveys conducted by >500 volunteers for three citizen science organizations (BeachCOMBERS, Beach Watch, COASST) at >225 sites from Cape Flattery, WA to Monterey Bay, CA were used to document the event and contrast it to regionally specific long-term average carcass-fall. Data are abundance of independently verified carcass identifications collected (bi)monthly at known locations and dates, providing an instantaneous index of "new" carcass encounter rate. Two pulses were evident: A small but significant anomaly (+2-3 carcasses/km) in November primarily in California and a much larger (+20-25 carcasses/km) more sustained anomaly in December-January along the Washington and northern Oregon coastline. Four non-exclusive hypotheses were examined: surplus production of young-of-the year (i.e. elevated post-breeding mortality), severity of fall/winter storms (i.e. elevated winterkill), shifts in food diversity (proxied as copepod regional diversity along the Newport Line), and habitat compression calculated as location and relative area of wintering habitat (assessed by GLS-tagged birds) with a monthly SST anomaly event can be explained by the extreme compression of cold water habitat in July-September 2014, trapping dispersing Scott Islands birds as the warm water anomaly expanded eastward, leaving open the question of whether this event was anomalous mortality and/or anomalously high beaching rates.

  14. Mortality displacement as a function of heat event strength in 7 US cities.

    Science.gov (United States)

    Saha, Michael V; Davis, Robert E; Hondula, David M

    2014-02-15

    Mortality rates increase immediately after periods of high air temperature. In the days and weeks after heat events, time series may exhibit mortality displacement-periods of lower than expected mortality. We examined all-cause mortality and meteorological data from 1980 to 2009 in the cities of Atlanta, Georgia; Boston, Massachusetts; Minneapolis-St. Paul, Minnesota; Philadelphia, Pennsylvania; Phoenix, Arizona; Seattle, Washington; and St. Louis, Missouri. We modeled baseline mortality using a generalized additive model. Heat waves were defined as periods of 3 or more consecutive days in which the apparent temperature exceeded a variable percentile. For each heat wave, we calculated the sum of excess and deficit mortality. Mortality displacement, which is the ratio of grand sum deficit to grand sum excess mortality, decreased as a function of event strength in all cities. Displacement was close to 1.00 for the weakest events. At the highest temperatures, displacement varied from 0.35 (95% confidence interval: 0.21, 0.55) to 0.75 (95% confidence interval: 0.54, 0.97). We found strong evidence of acclimatization across cities. Without consideration of displacement effects, the net impacts of heat-wave mortality are likely to be significant overestimations. A statistically significant positive relationship between the onset temperature of nondisplaced heat mortality and mean warm-season temperature (R(2) = 0.78, P < 0.01) suggests that heat mortality thresholds may be predictable across cities.

  15. Aerosol Indirect Effect on Warm Clouds over Eastern China Using Combined CALIOP and MODIS Observations

    Science.gov (United States)

    Guo, Jianping; Wang, Fu; Huang, Jingfeng; Li, Xiaowen

    2015-04-01

    Aerosol, one of key components of the climate system, is highly variable, both temporally and spatially. It often exerts great influences on the cloud-precipitation chain processes by serving as CCN/IN, altering cloud microphysics and its life cycle. Yet, the aerosol indirect effect on clouds remains largely unknown, because the initial changes in clouds due to aerosols may be enhanced or dampened by such feedback processes as modified cloud dynamics, or evaporation of the smaller droplets due to the competition for water vapor. In this study, we attempted to quantify the aerosol effects on warm cloud over eastern China, based on near-simultaneous retrievals from MODIS/AQUA, CALIOP/CALIPSO and CPR/CLOUDSAT during the period 2006 to 2010. The seasonality of aerosol from ground-based PM10 is quite different from that estimated from MODIS AOD. This result is corroborated by lower level profile of aerosol occurrence frequency from CALIOP, indicating the significant role CALIOP could play in aerosol-cloud interaction. The combined use of CALIOP and CPR facilitate the process to exactly determine the (vertical) position of warm cloud relative to aerosol, out of six scenarios in terms of aerosol-cloud mixing status in terms of aerosol-cloud mixing status, which shows as follows: AO (Aerosol only), CO (Cloud only), SASC (Single aerosol-single cloud), SADC (single aerosol-double cloud), DASC (double aerosol-single cloud), and others. Results shows that about 54% of all the cases belong to mixed status, among all the collocated aerosol-cloud cases. Under mixed condition, a boomerang shape is observed, i.e., reduced cloud droplet radius (CDR) is associated with increasing aerosol at moderate aerosol pollution (AODcases. We categorize dataset into warm-season and cold-season subsets to figure out how the boomerang shape varies with season. For moderate aerosol loading (AODMixed" cases is greater during cold season (denoted by a large slope), as compared with that during warm

  16. Quantifying Projected Heat Mortality Impacts under 21st-Century Warming Conditions for Selected European Countries.

    Science.gov (United States)

    Kendrovski, Vladimir; Baccini, Michela; Martinez, Gerardo Sanchez; Wolf, Tanja; Paunovic, Elizabet; Menne, Bettina

    2017-07-05

    Under future warming conditions, high ambient temperatures will have a significant impact on population health in Europe. The aim of this paper is to quantify the possible future impact of heat on population mortality in European countries, under different climate change scenarios. We combined the heat-mortality function estimated from historical data with meteorological projections for the future time laps 2035-2064 and 2071-2099, developed under the Representative Concentration Pathways (RCP) 4.5 and 8.5. We calculated attributable deaths (AD) at the country level. Overall, the expected impacts will be much larger than the impacts we would observe if apparent temperatures would remain in the future at the observed historical levels. During the period 2071-2099, an overall excess of 46,690 and 117,333 AD per year is expected under the RCP 4.5 and RCP 8.5 scenarios respectively, in addition to the 16,303 AD estimated under the historical scenario. Mediterranean and Eastern European countries will be the most affected by heat, but a non-negligible impact will be still registered in North-continental countries. Policies and plans for heat mitigation and adaptation are needed and urgent in European countries in order to prevent the expected increase of heat-related deaths in the coming decades.

  17. Seasonal modulation of the Asian summer monsoon between the Medieval Warm Period and Little Ice Age: a multi model study

    Science.gov (United States)

    Kamae, Youichi; Kawana, Toshi; Oshiro, Megumi; Ueda, Hiroaki

    2017-12-01

    Instrumental and proxy records indicate remarkable global climate variability over the last millennium, influenced by solar irradiance, Earth's orbital parameters, volcanic eruptions and human activities. Numerical model simulations and proxy data suggest an enhanced Asian summer monsoon during the Medieval Warm Period (MWP) compared to the Little Ice Age (LIA). Using multiple climate model simulations, we show that anomalous seasonal insolation over the Northern Hemisphere due to a long cycle of orbital parameters results in a modulation of the Asian summer monsoon transition between the MWP and LIA. Ten climate model simulations prescribing historical radiative forcing that includes orbital parameters consistently reproduce an enhanced MWP Asian monsoon in late summer and a weakened monsoon in early summer. Weakened, then enhanced Northern Hemisphere insolation before and after June leads to a seasonally asymmetric temperature response over the Eurasian continent, resulting in a seasonal reversal of the signs of MWP-LIA anomalies in land-sea thermal contrast, atmospheric circulation, and rainfall from early to late summer. This seasonal asymmetry in monsoon response is consistently found among the different climate models and is reproduced by an idealized model simulation forced solely by orbital parameters. The results of this study indicate that slow variation in the Earth's orbital parameters contributes to centennial variability in the Asian monsoon transition.[Figure not available: see fulltext.

  18. Sphagnum-dwelling testate amoebae in subarctic bogs are more sensitive to soil warming in the growing season than in winter: the results of eight-year field climate manipulations.

    NARCIS (Netherlands)

    Tsyganov, A.N.; Aerts, R.; Nijs, I.; Cornelissen, J.H.C.; Beyens, L.

    2012-01-01

    Sphagnum-dwelling testate amoebae are widely used in paleoclimate reconstructions as a proxy for climate-induced changes in bogs. However, the sensitivity of proxies to seasonal climate components is an important issue when interpreting proxy records. Here, we studied the effects of summer warming,

  19. Effect modification of the association between temperature variability and daily cardiovascular mortality by air pollutants in three Chinese cities.

    Science.gov (United States)

    Luo, Kai; Li, Runkui; Wang, Zongshuang; Zhang, Ruiming; Xu, Qun

    2017-11-01

    There is limited evidence showing the mortality effects of temperature variability (TV) on cardiovascular diseases. The joint effects between TV and air pollutants are also less well-established. This study aims to assess the effect modification of TV-cardiovascular mortality by air pollutants in three Chinese cities (Beijing, Nanjing and Chengdu). Data of daily mortality, air pollutants and meteorological factors from 2008 to 2011 was collected from each city. TV was calculated as the standard deviation of daily maximum and minimum temperatures over exposure days. The city-specific effect estimates of TV on cardiovascular mortality were calculated using a quasi-Poisson regression model, adjusting for potential confounders (e.g., seasonality and temperature). An interaction term of TV and a three-level air pollutants stratum indicator was included in the models. Effect modifications by air pollutants were assessed by comparing the estimates of TV's effect between pollutant stratums and calculating the corresponding 95% confidential interval of the differences. Multivariate meta-analysis was conducted to obtain the pooled estimates. The data showed that TV was associated with increased risk of cardiovascular mortality, especially for longer TV exposure days (0-8 days, TV08). This association was still observed after adjusting for air pollutants on current day or the previous two days. Stronger estimates were observed in females, but no significant difference between males and females was detected, indicating the absence of evidence of effect modification by gender. Estimates of TV-cardiovascular mortality varied across two season periods (warm and cool season) and age groups, but the evidence of effect modification by age and seasons was absent. Regarding the effect modification of TV-cardiovascular mortality association by air pollutants, a significant effect modification was identified for PM 10, but not for NO 2 and SO 2 in the whole population for all TV

  20. The Role of Frozen Soil in Groundwater Discharge Predictions for Warming Alpine Watersheds

    Science.gov (United States)

    Evans, Sarah G.; Ge, Shemin; Voss, Clifford I.; Molotch, Noah P.

    2018-03-01

    Climate warming may alter the quantity and timing of groundwater discharge to streams in high alpine watersheds due to changes in the timing of the duration of seasonal freezing in the subsurface and snowmelt recharge. It is imperative to understand the effects of seasonal freezing and recharge on groundwater discharge to streams in warming alpine watersheds as streamflow originating from these watersheds is a critical water resource for downstream users. This study evaluates how climate warming may alter groundwater discharge due to changes in seasonally frozen ground and snowmelt using a 2-D coupled flow and heat transport model with freeze and thaw capabilities for variably saturated media. The model is applied to a representative snowmelt-dominated watershed in the Rocky Mountains of central Colorado, USA, with snowmelt time series reconstructed from a 12 year data set of hydrometeorological records and satellite-derived snow covered area. Model analyses indicate that the duration of seasonal freezing in the subsurface controls groundwater discharge to streams, while snowmelt timing controls groundwater discharge to hillslope faces. Climate warming causes changes to subsurface ice content and duration, rerouting groundwater flow paths but not altering the total magnitude of future groundwater discharge outside of the bounds of hydrologic parameter uncertainties. These findings suggest that frozen soil routines play an important role for predicting the future location of groundwater discharge in watersheds underlain by seasonally frozen ground.

  1. The role of frozen soil in groundwater discharge predictions for warming alpine watersheds

    Science.gov (United States)

    Evans, Sarah G.; Ge, Shemin; Voss, Clifford I.; Molotch, Noah P.

    2018-01-01

    Climate warming may alter the quantity and timing of groundwater discharge to streams in high alpine watersheds due to changes in the timing of the duration of seasonal freezing in the subsurface and snowmelt recharge. It is imperative to understand the effects of seasonal freezing and recharge on groundwater discharge to streams in warming alpine watersheds as streamflow originating from these watersheds is a critical water resource for downstream users. This study evaluates how climate warming may alter groundwater discharge due to changes in seasonally frozen ground and snowmelt using a 2‐D coupled flow and heat transport model with freeze and thaw capabilities for variably saturated media. The model is applied to a representative snowmelt‐dominated watershed in the Rocky Mountains of central Colorado, USA, with snowmelt time series reconstructed from a 12 year data set of hydrometeorological records and satellite‐derived snow covered area. Model analyses indicate that the duration of seasonal freezing in the subsurface controls groundwater discharge to streams, while snowmelt timing controls groundwater discharge to hillslope faces. Climate warming causes changes to subsurface ice content and duration, rerouting groundwater flow paths but not altering the total magnitude of future groundwater discharge outside of the bounds of hydrologic parameter uncertainties. These findings suggest that frozen soil routines play an important role for predicting the future location of groundwater discharge in watersheds underlain by seasonally frozen ground.

  2. Plaice egg mortality: can we determine survivorschip?

    NARCIS (Netherlands)

    Dickey-Collas, M.; Fox, C.J.; Nash, R.D.M.; O'Brien, C.M.

    2003-01-01

    The daily mortality rate of cohorts of plaice eggs in the Irish Sea is estimated throughout the spawning season in 1995 and 2000, using general additive models of egg production. Daily mortality (z) was found to vary between 0.15 and 0.29. Mortality rates declined through the season in 1995 but not

  3. Seasonal forecasts: communicating current climate variability in southern Africa

    CSIR Research Space (South Africa)

    Landman, WA

    2011-11-01

    Full Text Available seasonal time scale. Seasonal climate forecasts are defined as probabilistic predictions of how much rain is expected during the season and how warm or cool it will be, based primarily on the principle that the ocean (sea-surface temperatures) influences...

  4. Excess mortality in winter in Finnish intensive care.

    Science.gov (United States)

    Reinikainen, M; Uusaro, A; Ruokonen, E; Niskanen, M

    2006-07-01

    In the general population, mortality from acute myocardial infarctions, strokes and respiratory causes is increased in winter. The winter climate in Finland is harsh. The aim of this study was to find out whether there are seasonal variations in mortality rates in Finnish intensive care units (ICUs). We analysed data on 31,040 patients treated in 18 Finnish ICUs. We measured severity of illness with acute physiology and chronic health evaluation II (APACHE II) scores and intensity of care with therapeutic intervention scoring system (TISS) scores. We assessed mortality rates in different months and seasons and used logistic regression analysis to test the independent effect of various seasons on hospital mortality. We defined 'winter' as the period from December to February, inclusive. The crude hospital mortality rate was 17.9% in winter and 16.4% in non-winter, P = 0.003. Even after adjustment for case mix, winter season was an independent risk factor for increased hospital mortality (adjusted odds ratio 1.13, 95% confidence interval 1.04-1.22, P = 0.005). In particular, the risk of respiratory failure was increased in winter. Crude hospital mortality was increased during the main holiday season in July. However, the severity of illness-adjusted risk of death was not higher in July than in other months. An increase in the mean daily TISS score was an independent predictor of increased hospital mortality. Severity of illness-adjusted hospital mortality for Finnish ICU patients is higher in winter than in other seasons.

  5. Integrated rice-duck farming mitigates the global warming potential in rice season.

    Science.gov (United States)

    Xu, Guochun; Liu, Xin; Wang, Qiangsheng; Yu, Xichen; Hang, Yuhao

    2017-01-01

    Integrated rice-duck farming (IRDF), as a mode of ecological agriculture, is an important way to realize sustainable development of agriculture. A 2-year split-plot field experiment was performed to evaluate the effects of IRDF on methane (CH 4 ) and nitrous oxide (N 2 O) emissions and its ecological mechanism in rice season. This experiment was conducted with two rice farming systems (FS) of IRDF and conventional farming (CF) under four paddy-upland rotation systems (PUR): rice-fallow (RF), annual straw incorporating in rice-wheat rotation system (RWS), annual straw-based biogas residues incorporating in rice-wheat rotation system (RWB), and rice-green manure (RGM). During the rice growing seasons, IRDF decreased the CH 4 emission by 8.80-16.68%, while increased the N 2 O emission by 4.23-15.20%, when compared to CF. Given that CH 4 emission contributed to 85.83-96.22% of global warming potential (GWP), the strong reduction in CH 4 emission led to a significantly lower GWP of IRDF as compared to CF. The reason for this trend was because IRDF has significant effect on dissolved oxygen (DO) and soil redox potential (Eh), which were two pivotal factors for CH 4 and N 2 O emissions in this study. The IRDF not only mitigates the GWP, but also increases the rice yield by 0.76-2.43% compared to CF. Moreover, compared to RWS system, RF, RWB and RGM systems significantly reduced CH 4 emission by 50.17%, 44.89% and 39.51%, respectively, while increased N 2 O emission by 10.58%, 14.60% and 23.90%, respectively. And RWS system had the highest GWP. These findings suggest that mitigating GWP and improving rice yield could be simultaneously achieved by the IRDF, and employing suitable PUR would benefit for relieving greenhouse effect. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. How Will Climate Warming Affect Non-Native Pumpkinseed Lepomis gibbosus Populations in the U.K.?

    Directory of Open Access Journals (Sweden)

    Grzegorz Zięba

    Full Text Available Of the non-native fishes introduced to the U.K., the pumpkinseed is one of six species predicted to benefit from the forecasted climate warming conditions. To demonstrate the potential response of adults and their progeny to a water temperature increase, investigations of parental pumpkinseed acclimatization, reproduction and YOY over-wintering were carried out in outdoor experimental ponds under ambient and elevated water temperature regimes. No temperature effects were observed on either adult survivorship and growth, and none of the assessed reproductive activity variables (total spawning time, spawning season length, number of spawning bouts appeared to be responsible for the large differences observed in progeny number and biomass. However, it was demonstrated in a previous study [Zięba G. et al., 2010] that adults in the heated ponds began spawning earlier than those of the ambient ponds. Ambient ponds produced 2.8× more progeny than the heated ponds, but these progeny were significantly smaller, probably due to their late hatching date, and subsequently suffered very high mortality over the first winter. Pumpkinseed in the U.K. will clearly benefit from climate warming through earlier seasonal reproduction, resulting in larger progeny going into winter, and as a result, higher over-winter survivorship would be expected relative to that which occurs under the present climatic regime.

  7. Short dry spells in the wet season increase mortality of tropical pioneer seedlings.

    Science.gov (United States)

    Engelbrecht, Bettina M J; Dalling, James W; Pearson, Timothy R H; Wolf, Robert L; Gálvez, David A; Koehler, Tobias; Tyree, Melvin T; Kursar, Thomas A

    2006-06-01

    Variation in plant species performance in response to water availability offers a potential axis for temporal and spatial habitat partitioning and may therefore affect community composition in tropical forests. We hypothesized that short dry spells during the wet season are a significant source of mortality for the newly emerging seedlings of pioneer species that recruit in treefall gaps in tropical forests. An analysis of a 49-year rainfall record for three forests across a rainfall gradient in central Panama confirmed that dry spells of > or = 10 days during the wet season occur on average once a year in a deciduous forest, and once every other year in a semi-deciduous moist and an evergreen wet forest. The effect of wet season dry spells on the recruitment of pioneers was investigated by comparing seedling survival in rain-protected dry plots and irrigated control plots in four large artificially created treefall gaps in a semi-deciduous tropical forest. In rain-protected plots surface soil layers dried rapidly, leading to a strong gradient in water potential within the upper 10 cm of soil. Seedling survival for six pioneer species was significantly lower in rain-protected than in irrigated control plots after only 4 days. The strength of the irrigation effect differed among species, and first became apparent 3-10 days after treatments started. Root allocation patterns were significantly, or marginally significantly, different between species and between two groups of larger and smaller seeded species. However, they were not correlated with seedling drought sensitivity, suggesting allocation is not a key trait for drought sensitivity in pioneer seedlings. Our data provide strong evidence that short dry spells in the wet season differentially affect seedling survivorship of pioneer species, and may therefore have important implications to seedling demography and community dynamics.

  8. Exploring the association between heat and mortality in Switzerland between 1995 and 2013.

    Science.gov (United States)

    Ragettli, Martina S; Vicedo-Cabrera, Ana M; Schindler, Christian; Röösli, Martin

    2017-10-01

    Designing effective public health strategies to prevent adverse health effect of hot weather is crucial in the context of global warming. In Switzerland, the 2003 heat have caused an estimated 7% increase in all-cause mortality. As a consequence, the Swiss Federal Office of Public Health developed an information campaign to raise public awareness on heat threats. For a better understanding on how hot weather affects daily mortality in Switzerland, we assessed the effect of heat on daily mortality in eight Swiss cities and population subgroups from 1995 to 2013 using different temperature metrics (daily mean (Tmean), maximum (Tmax), minimum (Tmin) and maximum apparent temperature (Tappmax)), and aimed to evaluate variations of the heat effect after 2003 (1995-2002 versus 2004-2013). We applied conditional quasi-Poisson regression models with non-linear distributed lag functions to estimate temperature-mortality associations over all cities (1995-2013) and separately for two time periods (1995-2002, 2004-2013). Relative risks (RR) of daily mortality were estimated for increases in temperature from the median to the 98th percentile of the warm season temperature distribution. Over the whole time period, significant temperature-mortality relationships were found for all temperature indicators (RR (95% confidence interval): Tappmax: 1.12 (1.05; 1.18); Tmax: 1.15 (1.08-1.22); Tmean: 1.16 (1.09-1.23); Tmin 1.23 (1.15-1.32)). Mortality risks were higher at the beginning of the summer, especially for Tmin. In the more recent time period, we observed a non-significant reduction in the effect of high temperatures on mortality, with the age group > 74 years remaining the population at highest risk. High temperatures continue to be a considerable risk factor for human health in Switzerland after 2003. More effective public health measures targeting the elderly should be promoted with increased attention to the first heat events in summer and considering both high day-time and

  9. Ocean acidification exerts negative effects during warming conditions in a developing Antarctic fish.

    Science.gov (United States)

    Flynn, Erin E; Bjelde, Brittany E; Miller, Nathan A; Todgham, Anne E

    2015-01-01

    Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean warming interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 months). Using an integrative, experimental approach, our research examined the impacts of near-future warming [-1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined warming and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean warming and may experience negative physiological effects of ocean acidification only in

  10. Irrigation enhances local warming with greater nocturnal warming effects than daytime cooling effects

    Science.gov (United States)

    Chen, Xing; Jeong, Su-Jong

    2018-02-01

    To meet the growing demand for food, land is being managed to be more productive using agricultural intensification practices, such as the use of irrigation. Understanding the specific environmental impacts of irrigation is a critical part of using it as a sustainable way to provide food security. However, our knowledge of irrigation effects on climate is still limited to daytime effects. This is a critical issue to define the effects of irrigation on warming related to greenhouse gases (GHGs). This study shows that irrigation led to an increasing temperature (0.002 °C year-1) by enhancing nighttime warming (0.009 °C year-1) more than daytime cooling (-0.007 °C year-1) during the dry season from 1961-2004 over the North China Plain (NCP), which is one of largest irrigated areas in the world. By implementing irrigation processes in regional climate model simulations, the consistent warming effect of irrigation on nighttime temperatures over the NCP was shown to match observations. The intensive nocturnal warming is attributed to energy storage in the wetter soil during the daytime, which contributed to the nighttime surface warming. Our results suggest that irrigation could locally amplify the warming related to GHGs, and this effect should be taken into account in future climate change projections.

  11. Development of new techniques of using irradiation in the genetic improvement of warm season grasses and an assessment of the genetic and cytogenetic effects. Progress report, May 1, 1975--April 30, 1976

    International Nuclear Information System (INIS)

    Burton, G.W.; Hanna, W.W.

    1976-06-01

    Irradiation ( 60 Coγ source) was used for the genetic improvement of several warm season grasses and pearl millet. Results of plant breeding experiments using radioinduced mutants of Bermuda grass and millet are reported

  12. Future vegetation ecosystem response to warming climate over the Tibetan Plateau

    Science.gov (United States)

    Bao, Y.; Gao, Y.; Wang, Y.

    2017-12-01

    The amplified vegetation response to climate variability has been found over the Tibetan Plateau (TP) in recent decades. In this study, the potential impacts of 21st century climate change on the vegetation ecosystem over the TP are assessed based on the dynamic vegetation outputs of models from Coupled Model Intercomparison Project Phase 5 (CMIP5), and the sensitivity of the TP vegetation in response to warming climate was investigated. Models project a continuous and accelerating greening in future, especially in the eastern TP, which closely associates with the plant type upgrade due to the pronouncing warming in growing season.Vegetation leaf area index (LAI) increase well follows the global warming, suggesting the warming climate instead of co2 fertilization controlls the future TP plant growth. The warming spring may advance the start of green-up day and extend the growing season length. More carbon accumulation in vegetation and soil will intensify the TP carbon cycle and will keep it as a carbon sink in future. Keywords: Leaf Area Index (LAI), Climate Change, Global Dynamic Vegetation Models (DGVMs), CMIP5, Tibetan Plateau (TP)

  13. Projected changes of thermal growing season over Northern Eurasia in a 1.5 °C and 2 °C warming world

    Science.gov (United States)

    Zhou, Baiquan; Zhai, Panmao; Chen, Yang; Yu, Rong

    2018-03-01

    Projected changes of the thermal growing season (TGS) over Northern Eurasia at 1.5 °C and 2 °C global warming levels are investigated using 22 CMIP5 models under both RCP4.5 and RCP8.5 scenarios. The multi-model mean projections indicate Northern Eurasia will experience extended and intensified TGSs in a warmer world. The prolongation of TGSs under 1.5 °C and 2 °C warming is attributed to both earlier onset and later termination, with the latter factor playing a dominating role. Interestingly, earlier onset is of greater importance under RCP4.5 than under RCP8.5 in prolonging TGS as the world warms by an additional 0.5 °C. Under both RCPs, growing degree day sum (GDD) above 5 °C is anticipated to increase by 0 °C-450 °C days and 0 °C-650 °C days over Northern Eurasia at 1.5 °C and 2 °C warming, respectively. However, effective GDD (EGDD) which accumulates optimum temperature for the growth of wheat, exhibits a decline in the south of Central Asia under warmer climates. Therefore, for wheat production over Northern Eurasia, adverse effects incurred by scorching temperatures and resultant inadequacy in water availability may counteract benefits from lengthening and warming TGS. In response to a future 1.5 °C and 2 °C warmer world, proper management and scientifically-tailored adaptation are imperative to optimize local-regional agricultural production.

  14. The impact of heat waves on mortality in seven major cities in Korea.

    Science.gov (United States)

    Son, Ji-Young; Lee, Jong-Tae; Anderson, G Brooke; Bell, Michelle L

    2012-04-01

    Understanding the health impacts of heat waves is important, especially given anticipated increases in the frequency, duration, and intensity of heat waves due to climate change. We examined mortality from heat waves in seven major Korean cities for 2000 through 2007 and investigated effect modification by individual characteristics and heat wave characteristics (intensity, duration, and timing in season). Heat waves were defined as ≥ 2 consecutive days with daily mean temperature at or above the 98th percentile for the warm season in each city. We compared mortality during heat-wave days and non-heat-wave days using city-specific generalized linear models. We used Bayesian hierarchical models to estimate overall effects within and across all cities. In addition, we estimated effects of heat wave characteristics and effects according to cause of death and examined effect modification by individual characteristics for Seoul. Overall, total mortality increased 4.1% [95% confidence interval (CI): -6.1%, 15.4%] during heat waves compared with non-heat-wave days, with an 8.4% increase (95% CI: 0.1%, 17.3%) estimated for Seoul. Estimated mortality was higher for heat waves that were more intense, longer, or earlier in summer, although effects were not statistically significant. Estimated risks were higher for women versus men, older versus younger residents, those with no education versus some education, and deaths that occurred out of hospitals in Seoul, although differences among strata of individual characteristics were not statistically significant. Our findings support evidence of mortality impacts from heat waves and have implications for efforts to reduce the public health burden of heat waves.

  15. Seasonal and cryopreservation impacts on semen quality in boars

    Science.gov (United States)

    Seasonal boar infertility occurs worldwide and contributes to economic loss to the pork industry. The current study evaluated cooled vs cryopreserved semen quality of 11 Duroc boars collected in June (cool season) and August 2014 (warm season). Semen was cooled to 16°C (cooled) or frozen over liquid...

  16. Survival during the Breeding Season: Nest Stage, Parental Sex, and Season Advancement Affect Reed Warbler Survival.

    Directory of Open Access Journals (Sweden)

    Kaja Wierucka

    Full Text Available Avian annual survival has received much attention, yet little is known about seasonal patterns in survival, especially of migratory passerines. In order to evaluate survival rates and timing of mortality within the breeding season of adult reed warblers (Acrocephalus scirpaceus, mark-recapture data were collected in southwest Poland, between 2006 and 2012. A total of 612 individuals (304 females and 308 males were monitored throughout the entire breeding season, and their capture-recapture histories were used to model survival rates. Males showed higher survival during the breeding season (0.985, 95% CI: 0.941-0.996 than females (0.869, 95% CI: 0.727-0.937. Survival rates of females declined with the progression of the breeding season (from May to August, while males showed constant survival during this period. We also found a clear pattern within the female (but not male nesting cycle: survival was significantly lower during the laying, incubation, and nestling periods (0.934, 95% CI: 0.898-0.958, when birds spent much time on the nest, compared to the nest building and fledgling periods (1.000, 95% CI: 1.00-1.000, when we did not record any female mortality. These data (coupled with some direct evidence, like bird corpses or blood remains found next to/on the nest may suggest that the main cause of adult mortality was on-nest predation. The calculated survival rates for both sexes during the breeding season were high compared to annual rates reported for this species, suggesting that a majority of mortality occurs at other times of the year, during migration or wintering. These results have implications for understanding survival variation within the reproductive period as well as general trends of avian mortality.

  17. Relict Mountain Permafrost Area (Loess Plateau, China) Exhibits High Ecosystem Respiration Rates and Accelerating Rates in Response to Warming

    Science.gov (United States)

    Mu, Cuicui; Wu, Xiaodong; Zhao, Qian; Smoak, Joseph M.; Yang, Yulong; Hu, Lian; Zhong, Wen; Liu, Guimin; Xu, Haiyan; Zhang, Tingjun

    2017-10-01

    Relict permafrost regions are characterized by thin permafrost and relatively high temperatures. Understanding the ecosystem respiration rate (ERR) and its relationship with soil hydrothermal conditions in these areas can provide knowledge regarding the permafrost carbon cycle in a warming world. In this study, we examined a permafrost area, a boundary area, and a seasonally frozen ground area within a relict permafrost region on the east edge of the Qinghai-Tibetan Plateau, China. Measurements from July 2015 to September 2016 showed that the mean annual ecosystem CO2 emissions for the boundary area were greater than the permafrost area. The Q10 value of the ERRs in the seasonally frozen ground area was greater than the permafrost area, indicating that the carbon emissions in the nonpermafrost areas were more sensitive to warming. The 1 year open-top chamber (OTC) warming increased soil temperatures in both the permafrost and seasonally frozen ground areas throughout the year, and the warming increased the ERRs by 1.18 (0.99-1.38, with interquartile range) and 1.13 (0.75-1.54, with interquartile range) μmol CO2 m-2 s-1 in permafrost and seasonally frozen ground areas, respectively. The OTC warming increased annual ERRs by approximately 50% for both permafrost and seasonally frozen ground areas with half the increase occurring during the nongrowing seasons. These results suggest that the ERRs in relict permafrost are high in comparison with arctic regions, and the carbon balance in relict permafrost areas could be greatly changed by climate warming.

  18. Seasonal change in pupation behaviour and pupal mortality in a swallowtail butterfly

    Directory of Open Access Journals (Sweden)

    Stefanescu, C.

    2004-01-01

    Full Text Available Phenotypic plasticity in pupal colour has evolved to render cryptic pupae. Apart from characteristics of the pupation site, the photoperiod experienced by larvae is important in determining pupal colour, long and short photophases eliciting the formation of green and brown pupae, respectively. This seasonal polyphenismis often correlated with developmental pathway, green pupae developing directly and brown pupae entering into diapause. From 1996 to 2000, immature stages of Iphiclides podalirius were monitored on natural hostplants in NE Spain. Larvae were followed to the pupation site and pupal colour, characteristics of the pupation site and the fate of pupae were recorded. Before August, pupae were non-diapausing green while in early August they were dimorphic, after which, they were brown and overwintered. As theory predicts, differences in pupation sites in successive generations were found in relation to pupal colour. Green pupae occurred on the hostplants and brown pupae were found among the leaf litter. Mortality ranged from 14.3 to 100%. Bird predation was the major mortality factor for green pupae and was also important for brown pupae. Results suggest that preference for pupation sites in the litter in diapausing broods evolved to avoid strong bird predation on the hostplants. Preference for sites above ground level in summer generations may have evolved in response to both non-visual (small mammals and visual (avian predators.

  19. Relative effects of precipitation variability and warming on tallgrass prairie ecosystem function

    Directory of Open Access Journals (Sweden)

    P. A. Fay

    2011-10-01

    Full Text Available Precipitation and temperature drive many aspects of terrestrial ecosystem function. Climate change scenarios predict increasing precipitation variability and temperature, and long term experiments are required to evaluate the ecosystem consequences of interannual climate variation, increased growing season (intra-annual rainfall variability, and warming. We present results from an experiment applying increased growing season rainfall variability and year round warming in native tallgrass prairie. During ten years of study, total growing season rainfall varied 2-fold, and we found ~50–200% interannual variability in plant growth and aboveground net primary productivity (ANPP, leaf carbon assimilation (ACO2, and soil CO2 efflux (JCO2 despite only ~40% variation in mean volumetric soil water content (0–15 cm, Θ15. Interannual variation in soil moisture was thus amplified in most measures of ecosystem response. Differences between years in Θ15 explained the greatest portion (14–52% of the variation in these processes. Experimentally increased intra-annual season rainfall variability doubled the amplitude of intra-annual soil moisture variation and reduced Θ15 by 15%, causing most ecosystem processes to decrease 8–40% in some or all years with increased rainfall variability compared to ambient rainfall timing, suggesting reduced ecosystem rainfall use efficiency. Warming treatments increased soil temperature at 5 cm depth, particularly during spring, fall, and winter. Warming advanced canopy green up in spring, increased winter JCO2, and reduced summer JCO2 and forb ANPP, suggesting that the effects of warming differed in cooler versus warmer parts of the year. We conclude that (1 major ecosystem processes in this grassland may be substantially altered by predicted changes in

  20. Changes in the seasonality of Arctic sea ice and temperature

    Science.gov (United States)

    Bintanja, R.

    2012-04-01

    Observations show that the Arctic sea ice cover is currently declining as a result of climate warming. According to climate models, this retreat will continue and possibly accelerate in the near-future. However, the magnitude of this decline is not the same throughout the year. With temperatures near or above the freezing point, summertime Arctic sea ice will quickly diminish. However, at temperatures well below freezing, the sea ice cover during winter will exhibit a much weaker decline. In the future, the sea ice seasonal cycle will be no ice in summer, and thin one-year ice in winter. Hence, the seasonal cycle in sea ice cover will increase with ongoing climate warming. This in itself leads to an increased summer-winter contrast in surface air temperature, because changes in sea ice have a dominant influence on Arctic temperature and its seasonality. Currently, the annual amplitude in air temperature is decreasing, however, because winters warm faster than summer. With ongoing summer sea ice reductions there will come a time when the annual temperature amplitude will increase again because of the large seasonal changes in sea ice. This suggests that changes in the seasonal cycle in Arctic sea ice and temperature are closely, and intricately, connected. Future changes in Arctic seasonality (will) have an profound effect on flora, fauna, humans and economic activities.

  1. Harvesting Effects on Species Composition and Distribution of Cover Attributes in Mixed Native Warm-Season Grass Stands

    Directory of Open Access Journals (Sweden)

    Vitalis W. Temu

    2015-05-01

    Full Text Available Managing grasslands for forage and ground-nesting bird habitat requires appropriate defoliation strategies. Subsequent early-summer species composition in mixed stands of native warm-season grasses (Indiangrass (IG, Sorghastrum nutans, big bluestem (BB, Andropogon gerardii and little bluestem (LB, Schizachyrium scoparium responding to harvest intervals (treatments, 30, 40, 60, 90 or 120 d and durations (years in production was assessed. Over three years, phased May harvestings were initiated on sets of randomized plots, ≥90 cm apart, in five replications (blocks to produce one-, two- and three-year-old stands. Two weeks after harvest, the frequencies of occurrence of plant species, litter and bare ground, diagonally across each plot (line intercept, were compared. Harvest intervals did not influence proportions of dominant plant species, occurrence of major plant types or litter, but increased that of bare ground patches. Harvest duration increased the occurrence of herbaceous forbs and bare ground patches, decreased that of tall-growing forbs and litter, but without affecting that of perennial grasses, following a year with more September rainfall. Data suggest that one- or two-year full-season forage harvesting may not compromise subsequent breeding habitat for bobwhites and other ground-nesting birds in similar stands. It may take longer than a year’s rest for similar stands to recover from such changes in species composition.

  2. [Characteristics and adaptation of seasonal drought in southern China under the background of climate change. V. Seasonal drought characteristics division and assessment in southern China].

    Science.gov (United States)

    Huang, Wan-Hua; Sui, Yue; Yang, Xiao-Guang; Dai, Shu-Wei; Li, Mao-Song

    2013-10-01

    Zoning seasonal drought based on the study of drought characteristics can provide theoretical basis for formulating drought mitigation plans and improving disaster reduction technologies in different arid zones under global climate change. Based on the National standard of meteorological drought indices and agricultural drought indices and the 1959-2008 meteorological data from 268 meteorological stations in southern China, this paper analyzed the climatic background and distribution characteristics of seasonal drought in southern China, and made a three-level division of seasonal drought in this region by the methods of combining comprehensive factors and main factors, stepwise screening indices, comprehensive disaster analysis, and clustering analysis. The first-level division was with the annual aridity index and seasonal aridity index as the main indices and with the precipitation during entire year and main crop growing season as the auxiliary indices, dividing the southern China into four primary zones, including semi-arid zone, sub-humid zone, humid zone, and super-humid zone. On this basis, the four primary zones were subdivided into nine second-level zones, including one semi-arid area-temperate-cold semi-arid hilly area in Sichuan-Yunnan Plateau, three sub-humid areas of warm sub-humid area in the north of the Yangtze River, warm-tropical sub-humid area in South China, and temperate-cold sub-humid plateau area in Southwest China, three humid areas of temperate-tropical humid area in the Yangtze River Basin, warm-tropical humid area in South China, and warm humid hilly area in Southwest China, and two super-humid areas of warm-tropical super-humid area in South China and temperate-cold super-humid hilly area in the south of the Yangtze River and Southwest China. According to the frequency and intensity of multiple drought indices, the second-level zones were further divided into 29 third-level zones. The distribution of each seasonal drought zone was

  3. Is cold or warm blood cardioplegia superior for myocardial protection?

    Science.gov (United States)

    Abah, Udo; Roberts, Patrick Garfjeld; Ishaq, Muhammad; De Silva, Ravi

    2012-01-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether the use of warm or cold blood cardioplegia has superior myocardial protection. More than 192 papers were found using the reported search, of which 20 represented the best evidence to answer the clinical question. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. A good breadth of high-level evidence addressing this clinical dilemma is available, including a recent meta-analysis and multiple large randomized clinical trials. Yet despite this level of evidence, no clear significant clinical benefit has been demonstrated by warm or cold blood cardioplegia. This suggests that neither method is significantly superior and that both provide similar efficacy of myocardial protection. The meta-analysis, including 41 randomized control trials (5879 patients in total), concluded that although a lower cardiac enzyme release and improved postoperative cardiac index was demonstrated in the warm cardioplegia group, this benefit was not reflected in clinical outcomes, which were similar in both groups. This theme of benefit in biochemical markers, physiological metrics and non-fatal postoperative events in the warm cardioplegia group ran throughout the literature, in particular the ‘Warm Heart investigators’ who conducted a randomized trial of 1732 patients, demonstrated a reduction in postoperative low output syndrome (6.1 versus 9.3%, P = 0.01) in the warm cardioplegia group, but no significant drop in 30-day all-cause mortality (1.4 versus 2.5%, P = 0.12). However, their later follow-up indicates non-fatal postoperative events predict reduced late survival, independent of cardioplegia. A minority of studies suggested a benefit of cold cardioplegia over warm in particular patient subgroups: One group conducted a retrospective study of 520 patients who

  4. [Effects of Warming and Straw Application on Soil Respiration and Enzyme Activity in a Winter Wheat Cropland].

    Science.gov (United States)

    Chen, Shu-tao; Sang, Lin; Zhang, Xu; Hu, Zheng-hua

    2016-02-15

    In order to investigate the effects of warming and straw application on soil respiration and enzyme activity, a field experiment was performed from November 2014 to May 2015. Four treatments, which were control (CK), warming, straw application, and warming and straw application, were arranged in field. Seasonal variability in soil respiration, soil temperature and soil moisture for different treatments were measured. Urease, invertase, and catalase activities for different treatments were measured at the elongation, booting, and anthesis stages. The results showed that soil respiration in different treatments had similar seasonal variation patterns. Seasonal mean soil respiration rates for the CK, warming, straw application, and warming and straw application treatments were 1.46, 1.96, 1.92, and 2.45 micromol x (m2 x s)(-1), respectively. ANOVA indicated that both warming and straw applications significantly (P soil respiration compared to the control treatment. The relationship between soil respiration and soil temperature in different treatments fitted with the exponential regression function. The exponential regression functions explained 34.3%, 28.1%, 24.6%, and 32.0% variations of soil respiration for CK, warming, straw application, and warming and straw application treatments, respectively. Warming and straw applications significantly (P soil respiration and urease activity fitted with a linear regression function, with the P value of 0.061. The relationship between soil respiration and invertase (P = 0.013), and between soil respiration and catalase activity (P = 0.002) fitted well with linear regression functions.

  5. Association of Seasonal Climate Variability and Age-Specific Mortality in Northern Sweden before the Onset of Industrialization

    Directory of Open Access Journals (Sweden)

    Joacim Rocklöv

    2014-07-01

    Full Text Available Background and aims: Little is known about health impacts of climate in pre-industrial societies. We used historical data to investigate the association of temperature and precipitation with total and age-specific mortality in Skellefteå, northern Sweden, between 1749 and 1859. Methods: We retrieved digitized aggregated population data of the Skellefteå parish, and monthly temperature and precipitation measures. A generalized linear model was established for year to year variability in deaths by annual and seasonal average temperature and cumulative precipitation using a negative binomial function, accounting for long-term trends in population size. The final full model included temperature and precipitation of all four seasons simultaneously. Relative risks (RR with 95% confidence intervals (CI were calculated for total, sex- and age-specific mortality. Results: In the full model, only autumn precipitation proved statistically significant (RR 1.02; CI 1.00–1.03, per 1cm increase of autumn precipitation, while winter temperature (RR 0.98; CI 0.95–1.00, per 1 °C increase in temperature and spring precipitation (RR 0.98; CI 0.97–1.00 per 1 cm increase in precipitation approached significance. Similar effects were observed for men and women. The impact of climate variability on mortality was strongest in children aged 3–9, and partly also in older children. Infants, on the other hand, appeared to be less affected by unfavourable climate conditions. Conclusions: In this pre-industrial rural region in northern Sweden, higher levels of rain during the autumn increased the annual number of deaths. Harvest quality might be one critical factor in the causal pathway, affecting nutritional status and susceptibility to infectious diseases. Autumn rain probably also contributed to the spread of air-borne diseases in crowded living conditions. Children beyond infancy appeared most vulnerable to climate impacts.

  6. Seasonal variations of U.S. mortality rates: Roles of solar ultraviolet-B doses, vitamin D, gene exp ression, and infections.

    Science.gov (United States)

    Grant, William B; Bhattoa, Harjit Pal; Boucher, Barbara J

    2017-10-01

    Death rates in the U.S. show a pronounced seasonality. The broad seasonal variation shows about 25% higher death rates in winter than in summer with an additional few percent increase associated with the Christmas and New Year's holidays. A pronounced increase in death rates also starts in mid-September, shortly after the school year begins. The causes of death with large contributions to the observed seasonality include diseases of the circulatory system; the respiratory system; the digestive system; and endocrine, nutritional, and metabolic diseases. Researchers have identified several factors showing seasonal variation that could possibly explain the seasonal variations in mortality rate. These factors include seasonal variations in solar ultraviolet-B(UVB) doses and serum 25-hydroxyvitamin D [25(OH)D] concentrations, gene expression, ambient temperature and humidity, UVB effects on environmental pathogen load, environmental pollutants and allergens, and photoperiod (or length of day). The factors with the strongest support in this analysis are seasonal variations in solar UVB doses and 25(OH)D concentrations. In the U.S., population mean 25(OH)D concentrations range from 21ng/mL in March to 28ng/mL in August. Measures to ensure that all people had 25(OH)D concentrations >36ng/mL year round would probably reduce death rates significantly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Seasonally asymmetric enhancement of northern vegetation productivity

    Science.gov (United States)

    Park, T.; Myneni, R.

    2017-12-01

    Multiple evidences of widespread greening and increasing terrestrial carbon uptake have been documented. In particular, enhanced gross productivity of northern vegetation has been a critical role leading to observed carbon uptake trend. However, seasonal photosynthetic activity and its contribution to observed annual carbon uptake trend and interannual variability are not well understood. Here, we introduce a multiple-source of datasets including ground, atmospheric and satellite observations, and multiple process-based global vegetation models to understand how seasonal variation of land surface vegetation controls a large-scale carbon exchange. Our analysis clearly shows a seasonally asymmetric enhancement of northern vegetation productivity in growing season during last decades. Particularly, increasing gross productivity in late spring and early summer is obvious and dominant driver explaining observed trend and variability. We observe more asymmetric productivity enhancement in warmer region and this spatially varying asymmetricity in northern vegetation are likely explained by canopy development rate, thermal and light availability. These results imply that continued warming may facilitate amplifying asymmetric vegetation activity and cause these trends to become more pervasive, in turn warming induced regime shift in northern land.

  8. Effects of air pollution and seasons on health-related quality of life of Mongolian adults living in Ulaanbaatar: cross-sectional studies

    Directory of Open Access Journals (Sweden)

    Motoyuki Nakao

    2017-06-01

    Full Text Available Abstract Background Ulaanbaatar, Mongolia, is known as severely air-polluted city in the world due to increased coal consumption in the cold season. The health effects of air pollution in Mongolia such as mortality, morbidity and symptoms have been previously reported. However, the concept of health-related quality of life (HR-QoL, which refers to the individual’s perception of well-being, should also be included as an adverse health outcome of air pollution. Methods Surveys on the Mongolian people living in Ulaanbaatar were performed in the warm and cold seasons. Self-completed questionnaires on the subjects’ HR-QoL, data from health checkups and pulmonary function tests by respiratory specialists were collected for Mongolian adults aged 40–79 years (n = 666. Ambient PM2.5 and PM10 were concurrently sampled and the components were analyzed to estimate the source of air pollution. Results In logistic regression analyses, respiratory symptoms and smoke-rich fuels were associated with reduced HR-QoL (> 50th percentile vs. ≤ 50th percentile. PM 2.5 levels were much higher in the cold season (median 86.4 μg/m3 (IQR: 58.7–121.0 than in the warm season (12.2 μg/m3 (8.9–21.2. The receptor model revealed that the high PM2.5 concentration in the cold season could be attributed to solid fuel combustion. The difference in HR-QoL between subjects with and without ventilatory impairment was assessed after the stratification of the subjects by season and household fuel type. There were no significant differences in HR-QoL between subjects with and without ventilatory impairment regardless of household fuel type in the warm season. In contrast, subjects with ventilatory impairment who used smoke-rich fuel in the cold season had a significantly lower HR-QoL. Conclusions Our study showed that air pollution in Ulaanbaatar worsened in the cold season and was estimated to be contributed by solid fuel combustion. Various aspects of HR-QoL in

  9. Effects of air pollution and seasons on health-related quality of life of Mongolian adults living in Ulaanbaatar: cross-sectional studies.

    Science.gov (United States)

    Nakao, Motoyuki; Yamauchi, Keiko; Ishihara, Yoko; Omori, Hisamitsu; Ichinnorov, Dashtseren; Solongo, Bandi

    2017-06-23

    Ulaanbaatar, Mongolia, is known as severely air-polluted city in the world due to increased coal consumption in the cold season. The health effects of air pollution in Mongolia such as mortality, morbidity and symptoms have been previously reported. However, the concept of health-related quality of life (HR-QoL), which refers to the individual's perception of well-being, should also be included as an adverse health outcome of air pollution. Surveys on the Mongolian people living in Ulaanbaatar were performed in the warm and cold seasons. Self-completed questionnaires on the subjects' HR-QoL, data from health checkups and pulmonary function tests by respiratory specialists were collected for Mongolian adults aged 40-79 years (n = 666). Ambient PM2.5 and PM10 were concurrently sampled and the components were analyzed to estimate the source of air pollution. In logistic regression analyses, respiratory symptoms and smoke-rich fuels were associated with reduced HR-QoL (> 50th percentile vs. ≤ 50th percentile). PM 2.5 levels were much higher in the cold season (median 86.4 μg/m 3 (IQR: 58.7-121.0)) than in the warm season (12.2 μg/m 3 (8.9-21.2). The receptor model revealed that the high PM2.5 concentration in the cold season could be attributed to solid fuel combustion. The difference in HR-QoL between subjects with and without ventilatory impairment was assessed after the stratification of the subjects by season and household fuel type. There were no significant differences in HR-QoL between subjects with and without ventilatory impairment regardless of household fuel type in the warm season. In contrast, subjects with ventilatory impairment who used smoke-rich fuel in the cold season had a significantly lower HR-QoL. Our study showed that air pollution in Ulaanbaatar worsened in the cold season and was estimated to be contributed by solid fuel combustion. Various aspects of HR-QoL in subjects with ventilatory impairment using smoke-rich fuels deteriorated

  10. Species-specific vulnerability of Arctic copepods to oil contamination and global warming

    DEFF Research Database (Denmark)

    Dinh, Khuong Van; Nielsen, Torkel Gissel

    Arctic ecosystems are predicted to have more severe effects from global warming as during the last decades the temperatures have increased in this region at a rate of 2-4 times higher than the global average. In addition, oil exploitation and shipping activities in the Arctic are predicted...... to increase under global warming as the result of the retreat of sea ice, posing the risk of oil contamination. It is poorly known how cold adapted copepods in the Arctic deal with the combined effects of global warming and oil exposure. To address this, we exposed females of two copepods species Calanus...... of temperatures. Notably, exposure to high pyrene resulted in ca. 70% of mortality in C. finmarchicus, the species with North Atlantic Origin, that was two times higher than the mortality observed for C. glacialis, the true Arctic species. These results suggest that extreme temperature under global warming...

  11. Multicity study of air pollution and mortality in Latin America (the ESCALA study).

    Science.gov (United States)

    Romieu, Isabelle; Gouveia, Nelson; Cifuentes, Luis A; de Leon, Antonio Ponce; Junger, Washington; Vera, Jeanette; Strappa, Valentina; Hurtado-Díaz, Magali; Miranda-Soberanis, Victor; Rojas-Bracho, Leonora; Carbajal-Arroyo, Luz; Tzintzun-Cervantes, Guadalupe

    2012-10-01

    concentration of O3. Most of the results for PM10 were positive and statistically significant, showing an increased risk of mortality with increased ambient concentrations. Results for O3 also showed a statistically significant increase in mortality in the cities with available data. With the distributed lag model, DLM 0-3, PM10 ambient concentrations were associated with an increased risk of mortality in all cities except Concepci6n and Temuco. In Mexico City and Santiago the RPC and 95% CIs were 1.02% (0.87 to 1.17) and 0.48% (0.35 to 0.61), respectively. PM10 was also significantly associated with increased mortality from cardiopulmonary, respiratory, cardiovascular, cerebrovascular-stroke, and chronic obstructive lung diseases (COPD) in most cities. The few nonsignificant effects generally were observed in the smallest cities (Concepción, Temuco, and Toluca). The percentage increases in mortality associated with ambient O3 concentrations were smaller than for those associated with PM10. All-natural-cause mortality was significantly related to O3 in Mexico City, Monterrey, São Paulo and Rio de Janeiro. Increased mortality risks for some specific causes were also observed in these cities and in Santiago. In the analyses stratified by season, different patterns in mortality and O3 were observed for cold and warm seasons. Risk estimates for the warm season were larger and significant for several causes of death in São Paulo and Rio de Janeiro. Risk estimates for the cold season were larger and significant for some causes of death in Mexico City, Monterrey, and Toluca. In an analysis stratified by SES, the all-natural-cause mortality risk in Mexico City was larger for people with a medium SES; however we observed that the risk of mortality related to respiratory causes was larger among people with a low SES, while the risk of mortality related to cardiovascular and cerebrovascular-stroke causes was larger among people with medium or high SES. In São Paulo, the all

  12. Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming.

    Science.gov (United States)

    Faubert, Patrick; Tiiva, Päivi; Rinnan, Asmund; Michelsen, Anders; Holopainen, Jarmo K; Rinnan, Riikka

    2010-07-01

    *Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. *We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. *The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5 degrees C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds. *The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects.

  13. Distribution and seasonal change of the Tsugaru warm current water off Rokkasho

    International Nuclear Information System (INIS)

    Shima, Shigeki; Nakayama, Tomoharu; Iseda, Kenichi; Nishizawa, Keisuke; Gasa, Shinichi; Suto, Kazuhiko; Sakurai, Satoshi; Oguri, Kazumasa; Kouzuma, Kiyotake

    2000-01-01

    The first commercial spent fuel reprocessing plant in Japan is being installed in Rokkasho-mura, Aomori Prefecture. Decontaminated liquid effluents in its operation will be released into a sea. In accessing the environmental impact of radionuclides discharged into a sea, it is important that the patterns of water movements around the discharge outlet are clarified. This area off Rokkasho is an open coast, where the Tsugaru Warm Current Water (TWC), the cold Oyashio and the warm Kuroshio Extension meet. Therefore, it is considered that complicated water circulations will be formed around the region of the wastewater outlet. Current structures of the coastal water near the ocean outlet were investigated by use of mooring current meters/ADCPs, a towing-ADCP, and some CTD observations. In addition, extensive observations with CTD and a shipboard ADCP were made in detail around the off Rokkasho (Shimokita Peninsula) to evaluate the distribution and the seasonal change of the TWC. These observations were carried out five times in September 1997 to August 1999. Gyre mode and coastal mode of the TWC experimentally pointed out by Conlon are found by those investigations. In the gyre mode, the large eddy more than 100 km in diameter is found in the east part of the Tsugaru Strait, which has the vertical structure of 1,000 m in depth. From the current measurements by shipboard ADCP, the velocity of the TWC was more than three knots and the width of its fastest region about 30km at that mode. On the other hand, in the coastal mode, the TWC flows along the continental slope off Rokkasho (ca five miles off the coast) and is about 400m thick in depth. The TWC affects the layers below the sill depth of the Tsugaru Strait. In the gyre mode the TWC flows northward along the slope off Rokkasho, however, around the coastal zone standing near to the outlet, southward flow was observed predominantly. At the coastal mode, the northward flow was mostly observed around the coastal area

  14. Avoided heat-related mortality through climate adaptation strategies in three US cities.

    Science.gov (United States)

    Stone, Brian; Vargo, Jason; Liu, Peng; Habeeb, Dana; DeLucia, Anthony; Trail, Marcus; Hu, Yongtao; Russell, Armistead

    2014-01-01

    Heat-related mortality in US cities is expected to more than double by the mid-to-late 21st century. Rising heat exposure in cities is projected to result from: 1) climate forcings from changing global atmospheric composition; and 2) local land surface characteristics responsible for the urban heat island effect. The extent to which heat management strategies designed to lessen the urban heat island effect could offset future heat-related mortality remains unexplored in the literature. Using coupled global and regional climate models with a human health effects model, we estimate changes in the number of heat-related deaths in 2050 resulting from modifications to vegetative cover and surface albedo across three climatically and demographically diverse US metropolitan areas: Atlanta, Georgia, Philadelphia, Pennsylvania, and Phoenix, Arizona. Employing separate health impact functions for average warm season and heat wave conditions in 2050, we find combinations of vegetation and albedo enhancement to offset projected increases in heat-related mortality by 40 to 99% across the three metropolitan regions. These results demonstrate the potential for extensive land surface changes in cities to provide adaptive benefits to urban populations at risk for rising heat exposure with climate change.

  15. Avoided heat-related mortality through climate adaptation strategies in three US cities.

    Directory of Open Access Journals (Sweden)

    Brian Stone

    Full Text Available Heat-related mortality in US cities is expected to more than double by the mid-to-late 21st century. Rising heat exposure in cities is projected to result from: 1 climate forcings from changing global atmospheric composition; and 2 local land surface characteristics responsible for the urban heat island effect. The extent to which heat management strategies designed to lessen the urban heat island effect could offset future heat-related mortality remains unexplored in the literature. Using coupled global and regional climate models with a human health effects model, we estimate changes in the number of heat-related deaths in 2050 resulting from modifications to vegetative cover and surface albedo across three climatically and demographically diverse US metropolitan areas: Atlanta, Georgia, Philadelphia, Pennsylvania, and Phoenix, Arizona. Employing separate health impact functions for average warm season and heat wave conditions in 2050, we find combinations of vegetation and albedo enhancement to offset projected increases in heat-related mortality by 40 to 99% across the three metropolitan regions. These results demonstrate the potential for extensive land surface changes in cities to provide adaptive benefits to urban populations at risk for rising heat exposure with climate change.

  16. Autumn photosynthetic decline and growth cessation in seedlings of white spruce are decoupled under warming and photoperiod manipulations.

    Science.gov (United States)

    Stinziano, Joseph R; Way, Danielle A

    2017-08-01

    Climate warming is expected to increase the seasonal duration of photosynthetic carbon fixation and tree growth in high-latitude forests. However, photoperiod, a crucial cue for seasonality, will remain constant, which may constrain tree responses to warming. We investigated the effects of temperature and photoperiod on weekly changes in photosynthetic capacity, leaf biochemistry and growth in seedlings of a boreal evergreen conifer, white spruce [Picea glauca (Moench) Voss]. Warming delayed autumn declines in photosynthetic capacity, extending the period when seedlings had high carbon uptake. While photoperiod was correlated with photosynthetic capacity, short photoperiods did not constrain the maintenance of high photosynthetic capacity under warming. Rubisco concentration dynamics were affected by temperature but not photoperiod, while leaf pigment concentrations were unaffected by treatments. Respiration rates at 25 °C were stimulated by photoperiod, although respiration at the growth temperatures was increased in warming treatments. Seedling growth was stimulated by increased photoperiod and suppressed by warming. We demonstrate that temperature is a stronger control on the seasonal timing of photosynthetic down-regulation than is photoperiod. Thus, while warming can stimulate carbon uptake in boreal conifers, the extra carbon may be directed towards respiration rather than biomass, potentially limiting carbon sequestration under climate change. © 2017 John Wiley & Sons Ltd.

  17. Impact of climate change on mid-twenty-first century growing seasons in Africa

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Kerry H.; Vizy, Edward K. [The University of Texas at Austin, Department of Geological Sciences, Jackson School of Geosciences, Austin, TX (United States)

    2012-12-15

    Changes in growing seasons for 2041-2060 across Africa are projected using a regional climate model at 90-km resolution, and confidence in the predictions is evaluated. The response is highly regional over West Africa, with decreases in growing season days up to 20% in the western Guinean coast and some regions to the east experiencing 5-10% increases. A longer growing season up to 30% in the central and eastern Sahel is predicted, with shorter seasons in parts of the western Sahel. In East Africa, the short rains (boreal fall) growing season is extended as the Indian Ocean warms, but anomalous mid-tropospheric moisture divergence and a northward shift of Sahel rainfall severely curtails the long rains (boreal spring) season. Enhanced rainfall in January and February increases the growing season in the Congo basin by 5-15% in association with enhanced southwesterly moisture transport from the tropical Atlantic. In Angola and the southern Congo basin, 40-80% reductions in austral spring growing season days are associated with reduced precipitation and increased evapotranspiration. Large simulated reductions in growing season over southeastern Africa are judged to be inaccurate because they occur due to a reduction in rainfall in winter which is over-produced in the model. Only small decreases in the actual growing season are simulated when evapotranspiration increases in the warmer climate. The continent-wide changes in growing season are primarily the result of increased evapotranspiration over the warmed land, changes in the intensity and seasonal cycle of the thermal low, and warming of the Indian Ocean. (orig.)

  18. Global warming and climate change: control methods

    International Nuclear Information System (INIS)

    Laal, M.; Aliramaie, A.

    2008-01-01

    This paper aimed at finding causes of global warming and ways to bring it under control. Data based on scientific opinion as given by synthesis reports of news, articles, web sites, and books. global warming is the observed and projected increases in average temperature of Earth's atmosphere and oceans. Carbon dioxide and other air pollution that is collecting in the atmosphere like a thickening blanket, trapping the sun's heat and causing the planet to warm up. Pollution is one of the biggest man-made problems. Burning fossil fuels is the main factor of pollution. As average temperature increases, habitats, species and people are threatened by drought, changes in rainfall, altered seasons, and more violent storms and floods. Indeed the life cycle of nuclear power results in relatively little pollution. Energy efficiency, solar, wind and other renewable fuels are other weapons against global warming . Human activity, primarily burning fossil fuels, is the major driving factor in global warming . Curtailing the release of carbon dioxide into the atmosphere by reducing use of oil, gasoline, coal and employment of alternate energy, sources are the tools for keeping global warming under control. global warming can be slowed and stopped, with practical actions thal yield a cleaner, healthier atmosphere

  19. Effects of recent warm and cold spells on European plant phenology

    Science.gov (United States)

    Menzel, A.; Estrella, N.; Seifert, H.

    2009-04-01

    Numerous studies have concurrently documented a progressively earlier start for vegetation activity in spring and a lengthening of the growing season during the last 2 to 5 decades in the temperate northern hemisphere. In contrast to climatic factors influencing autumn phenology, the climate signal controlling spring and summer phenology is fairly well understood: nearly all phenophases correlate with temperatures in the preceding 1 to 3 months. The changes currently experienced by emergence of vegetation may reach 6 to 8 d per °C. But how will this well-known, often linearly described relationship change in case of more frequent and more stronger temperature extremes? We thus studied the temperature response of European phenological records to cold and warm spells using the COST725 data base (www.cost725.org). We restricted our analysis to the time period 1951-2006 due to the relatively better coverage of Europe by phenological records. Up to now, 20 European countries contributed more than 7 Mio. phenological observations to this data base including 64 species and 22 different phases. The phenological observations compiled originated from different sources and phenological networks. Unfortunately there is no entire coverage and the data are very lumped. Cold and warm spells were identified using daily mean temperature data (1951-2006) on a 0.5° grid for Europe provided by the EU-FP6 project ENSEMBLES (http://www.ensembles-eu.org, http://eca.knmi.nl). The study area covered Europe and was limited to 40°E. For the whole study period, mean monthly and seasonal mean temperatures well as the corresponding standard deviations were calculated for each grid point. The annual monthly or seasonal temperature at a grid point was defined as cold (very cold, warm, very warm) by its deviation from the long-term average (more than 1.5 or 3sd, respectively). Warm and cold spells were selected when either the percentages of crossing 1.5sd were greater than 50% for the total

  20. Effects of global warming on ancient mammalian communities and their environments.

    Directory of Open Access Journals (Sweden)

    Larisa R G DeSantis

    2009-06-01

    Full Text Available Current global warming affects the composition and dynamics of mammalian communities and can increase extinction risk; however, long-term effects of warming on mammals are less understood. Dietary reconstructions inferred from stable isotopes of fossil herbivorous mammalian tooth enamel document environmental and climatic changes in ancient ecosystems, including C(3/C(4 transitions and relative seasonality.Here, we use stable carbon and oxygen isotopes preserved in fossil teeth to document the magnitude of mammalian dietary shifts and ancient floral change during geologically documented glacial and interglacial periods during the Pliocene (approximately 1.9 million years ago and Pleistocene (approximately 1.3 million years ago in Florida. Stable isotope data demonstrate increased aridity, increased C(4 grass consumption, inter-faunal dietary partitioning, increased isotopic niche breadth of mixed feeders, niche partitioning of phylogenetically similar taxa, and differences in relative seasonality with warming.Our data show that global warming resulted in dramatic vegetation and dietary changes even at lower latitudes (approximately 28 degrees N. Our results also question the use of models that predict the long term decline and extinction of species based on the assumption that niches are conserved over time. These findings have immediate relevance to clarifying possible biotic responses to current global warming in modern ecosystems.

  1. Assessing spatial associations between thermal stress and mortality in Hong Kong: a small-area ecological study.

    Science.gov (United States)

    Thach, Thuan-Quoc; Zheng, Qishi; Lai, Poh-Chin; Wong, Paulina Pui-Yun; Chau, Patsy Yuen-Kwan; Jahn, Heiko J; Plass, Dietrich; Katzschner, Lutz; Kraemer, Alexander; Wong, Chit-Ming

    2015-01-01

    Physiological equivalent temperature (PET) is a widely used index to assess thermal comfort of the human body. Evidence on how thermal stress-related health effects vary with small geographical areas is limited. The objectives of this study are (i) to explore whether there were significant patterns of geographical clustering of thermal stress as measured by PET and mortality and (ii) to assess the association between PET and mortality in small geographical areas. A small area ecological cross-sectional study was conducted at tertiary planning units (TPUs) level. Age-standardized mortality rates (ASMR) and monthly deaths at TPUs level for 2006 were calculated for cause-specific diseases. A PET map with 100 m × 100 m resolution for the same period was derived from Hong Kong Urban Climatic Analysis Map data and the annual and monthly averages of PET for each TPU were computed. Global Moran's I and local indicator of spatial association (LISA) analyses were performed. A generalized linear mixed model was used to model monthly deaths against PET adjusted for socio-economic deprivation. We found positive spatial autocorrelation between PET and ASMR. There were spatial correlations between PET and ASMR, particularly in the north of Hong Kong Island, most parts of Kowloon, and across New Territories. A 1°C change in PET was associated with an excess risk (%) of 2.99 (95% CI: 0.50-5.48) for all natural causes, 4.75 (1.14-8.36) for cardiovascular, 7.39 (4.64-10.10) for respiratory diseases in the cool season, and 4.31 (0.12 to 8.50) for cardiovascular diseases in the warm season. Variations between TPUs in PET had an important influence on cause-specific mortality, especially in the cool season. PET may have an impact on the health of socio-economically deprived population groups. Our results suggest that targeting policy interventions at high-risk areas may be a feasible option for reducing PET-related mortality. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Comparing and contrasting Holocene and Eemian warm periods with greenhouse-gas-induced warming

    International Nuclear Information System (INIS)

    MacCracken, M.C.; Kutzbach, J.

    1990-01-01

    Periods of the past that are estimated to have been warmer than present are of great potential interest for comparison with simulations of future climates associated with greenhouse-gas-induced warming. Certain features of the climates of the mid-Holocene and Eemian periods, both interglacial maxima, are described. The simulated climatic responses to both types of forcing, in terms of land/ocean and latitudinal averages, are also compared. The zonal average and annual (or seasonal) average radiation fluxes associated with the different-from-present orbital conditions that existed for those interglacials are compared to the radiation flux associated with CO 2 -induced warming. There are some similarities but also significant differences in the two types of radiation flux perturbations, and there are both similarities and differences in the simulated climatic responses

  3. Responses of Contrasting Tree Functional Types to Air Warming and Drought

    Directory of Open Access Journals (Sweden)

    Elisabet Martínez-Sancho

    2017-11-01

    Full Text Available Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings of contrasting functional types. Pinus sylvestris, Quercus spp. and Castanea sativa seedlings were grown in a common garden experiment under four treatments: control, air warming, drought and their combination during two consecutive growing periods. Height and diameter increments, stomatal conductance and stem water potentials were measured during both growing seasons. Additionally, hydraulic parameters such as xylem-specific native and maximum hydraulic conductivities, and native percentage of loss of conductivity were measured at the end of the entire experiment. Our results clearly pointed to different adaptive strategies of the studied species. Scots pine displayed a relatively isohydric behavior with a strict stomata control prohibiting native embolism whereas sweet chestnut and oak as relatively anisohydric species displayed an increased loss of native conductivity as a results of low water potentials. Seasonal timing of shoot and diameter growth also differed among functional types influencing drought impacts. Additionally, the possibility of embolism reversal seemed to be limited under the study conditions.

  4. Holocene landscape response to seasonality of storms in the Mojave Desert

    Science.gov (United States)

    Miller, D.M.; Schmidt, K.M.; Mahan, S.A.; McGeehin, J.P.; Owen, L.A.; Barron, J.A.; Lehmkuhl, F.; Lohrer, R.

    2010-01-01

    New optically stimulated and radiocarbon ages for alluvial fan and lake deposits in the Mojave Desert are presented, which greatly improves the temporal resolution of surface processes. The new Mojave Desert climate-landscape record is particularly detailed for the late Holocene. Evidence from ephemeral lake deposits and landforms indicates times of sustained stream flow during a wet interval of the latter part of the Medieval Warm Period at ca. AD 1290 and during the Little Ice Age at ca. AD 1650. The former lakes postdate megadroughts of the Medieval Warm Period, whereas the latter match the Maunder Minimum of the Little Ice Age. Periods of alluvial fan aggradation across the Mojave Desert are 14-9 cal ka and 6-3 cal ka. This timing largely correlates to times of increased sea-surface temperatures in the Gulf of California and enhanced warm-season monsoons. This correlation suggests that sustained alluvial fan aggradation may be driven by intense summer-season storms. These data suggest that the close proximity of the Mojave Desert to the Pacific Ocean and the Gulf of California promotes a partitioning of landscape-process responses to climate forcings that vary with seasonality of the dominant storms. Cool-season Pacific frontal storms cause river flow, ephemeral lakes, and fan incision, whereas periods of intense warm-season storms cause hillslope erosion and alluvial fan aggradation. The proposed landscape-process partitioning has important implications for hazard mitigation given that climate change may increase sea-surface temperatures in the Gulf of California, which indirectly could increase future alluvial fan aggradation.

  5. Evaluation of Warm Season Turfgrass under Different Irrigation Regimes in Arid Region

    Directory of Open Access Journals (Sweden)

    Abdullah Mohd Hassan ALSHEHHI

    2010-09-01

    Full Text Available Turfgrasses play a very important role in enhancing quality of life in modern urban living. Water quantity is the most important challenge worldwide in establishing and maintaining quality turf. The present study was aimed to test the performance of three warm season turfgrasses under four water levels for plantation in arid zones. Pits (48 measuring 1m length x 1m width x 0.6 m depth were planted with four replications of Common Bermuda grass (Cynodon dactylon, Tifway Bermuda grass (Cynodon dactylon x transvaalensis and Seashore Paspalum grass (Paspalum vaginatum in complete randomized design (CRD. Irrigation was done daily with 15 l/plot during the first 4 weeks (establishment period and four irrigation levels (5, 10, and 15, 20 l/lot were maintained in the following 8 weeks (treatment period. Physical parameters (canopy temperatures, ambient temperature, leaf area, shoot production and relative water content were measured once in two week as well as the visual quality (shoot color, shoot density and shoot uniformity was assessed, however, chlorophyll analysis was done in the end of the study. It was found that temperature has significant effect on performance of turfgrasses. Canopy temperature was higher than ambient temperature in the three turfgrasses but it has different level in each variety. Five liter of water per day per square meter gave acceptable turf quality when ambient temperature ranged from 20 to 33�C. Seashore paspalum performed best followed by Tifway Bermuda grass and common Bermuda grass respectively.

  6. Development of new techniques of using irradiation in the genetic improvement of warm season grasses, the assessment of their genetic and cytogenetic effects and biomass production from grass. Annual progress report, November 1, 1979 to October 31, 1980

    International Nuclear Information System (INIS)

    Burton, G.W.; Hanna, W.W.

    1980-01-01

    New techniques are described for using irradiation and chemical mutagens in the genetic improvement of several warm season grasses. Genetic and cytogenetic effects of these treatments are also being studied

  7. Species biogeography predicts drought responses in a seasonally dry tropical forest

    Science.gov (United States)

    Schwartz, N.; Powers, J. S.; Vargas, G.; Xu, X.; Smith, C. M.; Brodribb, T.; Werden, L. K.; Becknell, J.; Medvigy, D.

    2017-12-01

    The timing, distribution, and amount of rainfall in the seasonal tropics have shifted in recent years, with consequences for seasonally dry tropical forests (SDTF). SDTF are sensitive to changing rainfall regimes and drought conditions, but sensitivity to drought varies substantially across species. One potential explanation of species differences is that species that experience dry conditions more frequently throughout their range will be better able to cope with drought than species from wetter climates, because species from drier climates will be better adapted to drought. An El-Niño induced drought in 2015 presented an opportunity to assess species-level differences in mortality in SDTF, and to ask whether the ranges of rainfall conditions species experience and the average rainfall regimes in species' ranges predict differences in mortality rates in Costa Rican SDTF. We used field plot data from northwest Costa Rica to determine species' level mortality rates. Mortality rates ranged substantially across species, with some species having no dead individuals to as high as 50% mortality. To quantify rainfall conditions across species' ranges, we used species occurrence data from the Global Biodiversity Information Facility, and rainfall data from the Chelsa climate dataset. We found that while the average and range of mean annual rainfall across species ranges did not predict drought-induced mortality in the field plots, across-range averages of the seasonality index, a measure of rainfall seasonality, was strongly correlated with species-level drought mortality (r = -0.62, p < 0.05), with species from more strongly seasonal climates experiencing less severe drought mortality. Furthermore, we found that the seasonality index was a stronger predictor of mortality than any individual functional trait we considered. This result shows that species' biogeography may be an important factor for how species will respond to future drought, and may be a more integrative

  8. Excess mortality during the warm summer of 2015 in Switzerland.

    Science.gov (United States)

    Vicedo-Cabrera, Ana M; Ragettli, Martina S; Schindler, Christian; Röösli, Martin

    2016-01-01

    In Switzerland, summer 2015 was the second warmest summer for 150 years (after summer 2003). For summer 2003, a 6.9% excess mortality was estimated for Switzerland, which corresponded to 975 extra deaths. The impact of the heat in summer 2015 in Switzerland has not so far been evaluated. Daily age group-, gender- and region-specific all-cause excess mortality during summer (June-August) 2015 was estimated, based on predictions derived from quasi-Poisson regression models fitted to the daily mortality data for the 10 previous years. Estimates of excess mortality were derived for 1 June to 31 August, at national and regional level, as well as by month and for specific heat episodes identified in summer 2015 by use of seven different definitions. 804 excess deaths (5.4%, 95% confidence interval [CI] 3.0‒7.9%) were estimated for summer 2015 compared with previous summers, with the highest percentage obtained for July (11.6%, 95% CI 3.7‒19.4%). Seventy-seven percent of deaths occurred in people aged 75 years and older. Ticino (10.3%, 95% CI -1.8‒22.4%), Northwestern Switzerland (9.5%, 95% CI 2.7‒16.3%) and Espace Mittelland (8.9%, 95% CI 3.7‒14.1%) showed highest excess mortality during this three-month period, whereas fewer deaths than expected (-3.3%, 95% CI -9.2‒2.6%) were observed in Eastern Switzerland, the coldest region. The largest excess estimate of 23.7% was obtained during days when both maximum apparent and minimum night-time temperature reached extreme values (+32 and +20 °C, respectively), with 31.0% extra deaths for periods of three days or more. Heat during summer 2015 was associated with an increase in mortality in the warmer regions of Switzerland and it mainly affected older people. Estimates for 2015 were only a little lower compared to those of summer 2003, indicating that mitigation measures to prevent heat-related mortality in Switzerland have not become noticeably effective in the last 10 years.

  9. Seasonal Changes in Central England Temperatures

    DEFF Research Database (Denmark)

    Proietti, Tommaso; Hillebrand, Eric

    The aim of this paper is to assess how climate change is reflected in the variation of the seasonal patterns of the monthly Central England Temperature time series between 1772 and 2013. In particular, we model changes in the amplitude and phase of the seasonal cycle. Starting from the seminal work...... by Thomson (“The Seasons, Global Temperature and Precession”, Science, 7 April 1995, vol 268, p. 59–68), a number of studies have documented a shift in the phase of the annual cycle implying an earlier onset of the spring season at various European locations. A significant reduction in the amplitude...... and stochastic trends, as well as seasonally varying autocorrelation and residual variances. The model can be summarized as containing a permanent and a transitory component, where global warming is captured in the permanent component, on which the seasons load differentially. The phase of the seasonal cycle...

  10. Variación estacional de la mortalidad en la ciudad de Valencia, España Seasonal variation of mortality rates within the city of Valencia, Spain

    Directory of Open Access Journals (Sweden)

    FERRAN BALLESTER-DÍEZ

    1997-03-01

    variable. La asociación de las variables de temperatura con la mortalidad es mayor en los grupos de edad más avanzada y en las mujeres. Conclusiones. Se observa una marcada variación estacional en la mortalidad por todas las causas en ambos sexos, con picos en las tasas de mortalidad en enero, y un menor número de defunciones en septiembre. La variación estacional en la mortalidad se hace mayor a medida que aumenta la edad, lo que no se aprecia en el grupo de edad más joven. Por sexos, el patrón estacional es más marcado en las mujeres que en los hombres, de tal modo que se aprecia una asociación positiva de mayor magnitud entre la mortalidad y la variable frío en los hombres del grupo de edad más elevado, y con la variable calor en las mujeres de mayor edad.Objective. To study the seasonal variation in mortality for all causes, grouped according to age and sex, within the city of Valencia during the period 1976-1990 and its relationship with air temperature. Material and methods. This is an ecological study using monthly global mortality and mean atmospheric temperature statistics for the city of Valencia, Spain between 1976 and 1990. The principal variable has turned out to be mortality for all causes. Mortality rates have been determined for specific age groups (0-4, 35-49, 50-64, 65-74 and > or = 75, as well as for both genders, within the city of Valencia for each of the 180-month period of investigation. Average monthly mortality data has been obtained and the percentage variation has been calculated. Graphical analysis has been used to examine the seasonal variation in mortality and in order to discern the nature of any relationship between atmospheric temperature and mortality. The regression line has been adjusted using the Loess method (smoothed regression motive, locally pondered. The association between mean temperature and mortality has calculated by means of multiple regression analysis controling for trend, seasonality and period effect. Results

  11. Anthropogenic Warming Impacts on Today's Sierra Nevada Snowpack and Flood Severity

    Science.gov (United States)

    Huang, X.; Hall, A. D.; Berg, N.

    2017-12-01

    Focusing on this recent extreme wet year over California, this study investigates the warming impacts on the snowpack and the flood severity over the Sierra Nevada (SN), where the majority of the precipitation occurs during the winter season and early spring. One of our goals is to quantify anthropogenic warming impacts on the snow water equivalent (SWE) including recent historical warming and prescribed future projected warming scenarios; This work also explores to what extent flooding risk has increased under those warming cases. With a good representation of the historical precipitation and snowpack over the Sierra Nevada from the historical reference run at 9km (using WRF), the results from the offline Noah-MP simulations with perturbed near-surface temperatures reveal magnificent impacts of warming to the loss of the average snowpack. The reduction of the SWE under warming mainly results from the decreased rain-to-snow conversion with a weaker effect from increased snowmelt. Compared to the natural case, the past industrial warming decreased the maximum SWE by about one-fifth averaged over the study area. Future continuing warming can result in around one-third reduction of current maximum SWE under RCP4.5 emissions scenario, and the loss can reach to two-thirds under RCP8.5 as a "business-as-usual" condition. The impact of past warming is particularly outstanding over the North SN region where precipitation dominates and over the middle elevation regions where the snow mainly distributes. In the future, the warming impact on SWE progresses to higher regions, and so to the south and east. Under the business-as-usual scenario, the projected mid-elevation snowpack almost disappears by April 1st with even high-elevation snow reduced by about half. Along with the loss of the snowpack, as the temperature warms, floods can also intensify with increased early season runoff especially under heavy-rainy days caused by the weakened rain-to-snow processes and

  12. Environmental DNA (eDNA) Detection Probability Is Influenced by Seasonal Activity of Organisms.

    Science.gov (United States)

    de Souza, Lesley S; Godwin, James C; Renshaw, Mark A; Larson, Eric

    2016-01-01

    Environmental DNA (eDNA) holds great promise for conservation applications like the monitoring of invasive or imperiled species, yet this emerging technique requires ongoing testing in order to determine the contexts over which it is effective. For example, little research to date has evaluated how seasonality of organism behavior or activity may influence detection probability of eDNA. We applied eDNA to survey for two highly imperiled species endemic to the upper Black Warrior River basin in Alabama, US: the Black Warrior Waterdog (Necturus alabamensis) and the Flattened Musk Turtle (Sternotherus depressus). Importantly, these species have contrasting patterns of seasonal activity, with N. alabamensis more active in the cool season (October-April) and S. depressus more active in the warm season (May-September). We surveyed sites historically occupied by these species across cool and warm seasons over two years with replicated eDNA water samples, which were analyzed in the laboratory using species-specific quantitative PCR (qPCR) assays. We then used occupancy estimation with detection probability modeling to evaluate both the effects of landscape attributes on organism presence and season of sampling on detection probability of eDNA. Importantly, we found that season strongly affected eDNA detection probability for both species, with N. alabamensis having higher eDNA detection probabilities during the cool season and S. depressus have higher eDNA detection probabilities during the warm season. These results illustrate the influence of organismal behavior or activity on eDNA detection in the environment and identify an important role for basic natural history in designing eDNA monitoring programs.

  13. Microbial biomass dynamics dominate N cycle responses to warming in a sub-arctic peatland

    Science.gov (United States)

    Weedon, J. T.; Aerts, R.; Kowalchuk, G. K.; van Bodegom, P. M.

    2012-04-01

    The balance of primary production and decomposition in sub-arctic peatlands may shift with climate change. Nitrogen availability will modulate this shift, but little is known about the drivers of soil nitrogen dynamics in these environments, and how they are influenced by rising soil temperatures. We used a long-term open top chamber warming experiment in Abisko, Sweden, to test for the interactive effects of spring warming, summer warming and winter snow addition on soil organic and inorganic nitrogen fluxes, potential activities of carbon and nitrogen cycle enzymes, and the structure of the soil-borne microbial communities. Summer warming increased the flux of soil organic nitrogen over the growing season, while simultaneously causing a seasonal decrease in microbial biomass, suggesting that N flux is driven by large late-season dieback of microbes. This change in N cycle dynamics was not reflected in any of the measured potential enzyme activities. Moreover, the soil microbial community structure was stable across treatments, suggesting non-specific microbial dieback. To further test whether the observed patterns were driven by direct temperature effects or indirect effects (via microbial biomass dynamics), we conducted follow-up controlled experiments in soil mesocosms. Experimental additions of dead microbial cells had stronger effects on N pool sizes and enzyme activities than either plant litter addition or a 5 °C alteration in incubation temperatures. Peat respiration was positively affected by both substrate addition and higher incubation temperatures, but the temperature-only effect was not sufficient to account for the increases in respiration observed in previous field experiments. We conclude that warming effects on peatland N cycling (and to some extent C cycling) are dominated by indirect effects, acting through alterations to the seasonal flux of microbe-derived organic matter. We propose that climate change models of soil carbon and nitrogen

  14. The changing seasonal climate in the Arctic.

    Science.gov (United States)

    Bintanja, R; van der Linden, E C

    2013-01-01

    Ongoing and projected greenhouse warming clearly manifests itself in the Arctic regions, which warm faster than any other part of the world. One of the key features of amplified Arctic warming concerns Arctic winter warming (AWW), which exceeds summer warming by at least a factor of 4. Here we use observation-driven reanalyses and state-of-the-art climate models in a variety of standardised climate change simulations to show that AWW is strongly linked to winter sea ice retreat through the associated release of surplus ocean heat gained in summer through the ice-albedo feedback (~25%), and to infrared radiation feedbacks (~75%). Arctic summer warming is surprisingly modest, even after summer sea ice has completely disappeared. Quantifying the seasonally varying changes in Arctic temperature and sea ice and the associated feedbacks helps to more accurately quantify the likelihood of Arctic's climate changes, and to assess their impact on local ecosystems and socio-economic activities.

  15. The Short-Term Effects of Visibility and Haze on Mortality in a Coastal City of China: A Time-Series Study

    Directory of Open Access Journals (Sweden)

    Shaohua Gu

    2017-11-01

    Full Text Available Few studies have been conducted to investigate the acute health effects of visibility and haze, which may be regarded as proxy indicators of ambient air pollution. We used a distributed lag non-linear model (DLNM combined with quasi-Poisson regression to estimate the relationship between visibility, haze and mortality in Ningbo, a coastal city of China. We found that the mortality risk of visibility was statistically significant only on the current day, while the risk of haze and PM10 peaked on the second day and could last for three days. When the visibility was less than 10 km, each 1 km decrease of visibility at lag 0 day was associated with a 0.78% (95% CI: 0.22–1.36% increase in total mortality and a 1.61% (95% CI: 0.39–2.85% increase in respiratory mortality. The excess risk of haze at lag 0–2 days on total mortality, cardiovascular and respiratory mortality was 7.76% (95% CI: 3.29–12.42%, 7.73% (95% CI: 0.12–15.92% and 17.77% (95% CI: 7.64–28.86%, respectively. Greater effects of air pollution were observed during the cold season than in the warm season, and the elderly were at higher risk compared to youths. The effects of visibility and haze were attenuated by single pollutants. These findings suggest that visibility and haze could be used as surrogates of air quality where pollutant data are scarce, and strengthen the evidence to develop policy to control air pollution and protect vulnerable populations.

  16. Heat-Related Mortality in a Warming Climate: Projections for 12 U.S. Cities

    Directory of Open Access Journals (Sweden)

    Elisaveta P. Petkova

    2014-10-01

    Full Text Available Heat is among the deadliest weather-related phenomena in the United States, and the number of heat-related deaths may increase under a changing climate, particularly in urban areas. Regional adaptation planning is unfortunately often limited by the lack of quantitative information on potential future health responses. This study presents an assessment of the future impacts of climate change on heat-related mortality in 12 cities using 16 global climate models, driven by two scenarios of greenhouse gas emissions. Although the magnitude of the projected heat effects was found to differ across time, cities, climate models and greenhouse pollution emissions scenarios, climate change was projected to result in increases in heat-related fatalities over time throughout the 21st century in all of the 12 cities included in this study. The increase was more substantial under the high emission pathway, highlighting the potential benefits to public health of reducing greenhouse gas emissions. Nearly 200,000 heat-related deaths are projected to occur in the 12 cities by the end of the century due to climate warming, over 22,000 of which could be avoided if we follow a low GHG emission pathway. The presented estimates can be of value to local decision makers and stakeholders interested in developing strategies to reduce these impacts and building climate change resilience.

  17. Heat-Related Mortality in a Warming Climate: Projections for 12 U.S. Cities

    Science.gov (United States)

    Petkova, Elisaveta P.; Bader, Daniel A.; Anderson, G. Brooke; Horton, Radley M.; Knowlton, Kim; Kinney, Patrick L.

    2014-01-01

    Heat is among the deadliest weather-related phenomena in the United States, and the number of heat-related deaths may increase under a changing climate, particularly in urban areas. Regional adaptation planning is unfortunately often limited by the lack of quantitative information on potential future health responses. This study presents an assessment of the future impacts of climate change on heat-related mortality in 12 cities using 16 global climate models, driven by two scenarios of greenhouse gas emissions. Although the magnitude of the projected heat effects was found to differ across time, cities, climate models and greenhouse pollution emissions scenarios, climate change was projected to result in increases in heat-related fatalities over time throughout the 21st century in all of the 12 cities included in this study. The increase was more substantial under the high emission pathway, highlighting the potential benefits to public health of reducing greenhouse gas emissions. Nearly 200,000 heat-related deaths are projected to occur in the 12 cities by the end of the century due to climate warming, over 22,000 of which could be avoided if we follow a low GHG emission pathway. The presented estimates can be of value to local decision makers and stakeholders interested in developing strategies to reduce these impacts and building climate change resilience.

  18. Seasonal Variations in Color Preference.

    Science.gov (United States)

    Schloss, Karen B; Nelson, Rolf; Parker, Laura; Heck, Isobel A; Palmer, Stephen E

    2017-08-01

    We investigated how color preferences vary according to season and whether those changes could be explained by the ecological valence theory (EVT). To do so, we assessed the same participants' preferences for the same colors during fall, winter, spring, and summer in the northeastern United States, where there are large seasonal changes in environmental colors. Seasonal differences were most pronounced between fall and the other three seasons. Participants liked fall-associated dark-warm colors-for example, dark-red, dark-orange (brown), dark-yellow (olive), and dark-chartreuse-more during fall than other seasons. The EVT could explain these changes with a modified version of Palmer and Schloss' (2010) weighted affective valence estimate (WAVE) procedure that added an activation term to the WAVE equation. The results indicate that color preferences change according to season, as color-associated objects become more/less activated in the observer. These seasonal changes in color preferences could not be characterized by overall shifts in weights along cone-contrast axes. Copyright © 2016 Cognitive Science Society, Inc.

  19. Cold-season solar input and ambivalent thermal behavior brought by climber greenwalls

    International Nuclear Information System (INIS)

    Jim, C.Y.

    2015-01-01

    Most greenwall studies focus on cooling and energy conservation in the warm season, and tropical cold-season has received little attention. This field-experimental study in humid-subtropical Hong Kong evaluated winter thermal behavior of climber greenwalls. Orientation and weather factors regulated solar-irradiation regimes with critical impact on vegetation thermal responses. Temperature differentiation occurred mainly on sunny day, with subdued variations on cloudy and rainy days. The south greenwall on sunny day received the highest solar-energy input, bringing divergent surface temperature in three climber species. The daytime descending cooling sequence was: Control-air > Pyrostegia venusta > Bauhinia corymbosa > Ficus pumila > Control-surface. Heat-sink effect related to foliage-thickness and moisture-content influenced climber thermal responses. Exceeding a solar-irradiance threshold of 500 Wm"−"2 was a prerequisite for notable solar-warming and transpiration-cooling, bringing well-differentiated climber-surface temperature. Cooling of vegetation-surface and Anterior-ambient-air was contrasted by warming behind the greenwall. Posterior-airgap with trapped stagnant air and Posterior-concrete-surface were warmed consistently above control concrete-surface on sunny and cloudy days. This winter passive warming mechanism denotes a new dimension in thermal benefits operating behind the greenwall. The thermal-gradient can transmit heat into indoor space, with benefits on human comfort, health and energy conservation. - Highlights: • Cold-season thermal regimes and benefits of climber greenwalls in tropics was studied. • Greenwall plots were installed as a field-experiment to evaluated six related factors. • Descending cooling sequence: Pyrostegia venusta > Bauhinia corymbosa > Ficus pumila. • Solar radiation intensity and foliage heat-sink effect determined climber cooling. • Posterior airgap and Posterior concrete-surface were warmed to provide indoor

  20. Assessing the relationship between global warming and mortality: Lag effects of temperature fluctuations by age and mortality categories

    Energy Technology Data Exchange (ETDEWEB)

    Yu Weiwei, E-mail: weiwei.yu@qut.edu.au [School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD 4050, Brisbane (Australia); Mengersen, Kerrie [Discipline of Mathematical Sciences, Faculty of Science and Technology, Queensland University of Technology, Brisbane (Australia); Hu Wenbiao [School of Population Health and Institute of Health and Biomedical Innovation, University of Queensland, Brisbane (Australia); Guo Yuming [School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD 4050, Brisbane (Australia); Pan Xiaochuan [School of Public Health, Peking University, Beijing 100191 (China); Tong Shilu, E-mail: s.tong@qut.edu.au [School of Public Health and Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, QLD 4050, Brisbane (Australia)

    2011-07-15

    Although interests in assessing the relationship between temperature and mortality have arisen due to climate change, relatively few data are available on lag structure of temperature-mortality relationship, particularly in the Southern Hemisphere. This study identified the lag effects of mean temperature on mortality among age groups and death categories using polynomial distributed lag models in Brisbane, Australia, a subtropical city, 1996-2004. For a 1 deg. C increase above the threshold, the highest percent increase in mortality on the current day occurred among people over 85 years (7.2% (95% CI: 4.3%, 10.2%)). The effect estimates among cardiovascular deaths were higher than those among all-cause mortality. For a 1 deg. C decrease below the threshold, the percent increases in mortality at 21 lag days were 3.9% (95% CI: 1.9%, 6.0%) and 3.4% (95% CI: 0.9%, 6.0%) for people aged over 85 years and with cardiovascular diseases, respectively. These findings may have implications for developing intervention strategies to reduce and prevent temperature-related mortality. - Highlights: > A longer lag effects in cold days and shorter lag effects in hot days. > The very old people were most vulnerable to temperature stress. > The cardiovascular mortality was also sensitive to the temperature variation. - In Brisbane, the lag effects lasted longer for cold temperatures, and shorter for hot temperatures. Elderly people and cardiovascular mortality were vulnerable to temperature stress.

  1. Birth seasonality and offspring production in threatened neotropical primates related to climate

    Science.gov (United States)

    Wiederholt, R.; Post, E.

    2011-01-01

    Given the threatened status of many primate species, the impacts of global warming on primate reproduction and, consequently, population growth should be of concern. We examined relations between climatic variability and birth seasonality, offspring production, and infant sex ratios in two ateline primates, northern muriquis, and woolly monkeys. In both species, the annual birth season was delayed by dry conditions and El Ni??o years, and delayed birth seasons were linked to lower birth rates. Additionally, increased mean annual temperatures were associated with lower birth rates for northern muriquis. Offspring sex ratios varied with climatic conditions in both species, but in different ways: directly in woolly monkeys and indirectly in northern muriquis. Woolly monkeys displayed an increase in the proportion of males among offspring in association with El Ni??o events, whereas in northern muriquis, increases in the proportion of males among offspring were associated with delayed onset of the birth season, which itself was related, although weakly, to warm, dry conditions. These results illustrate that global warming, increased drought frequency, and changes in the frequency of El Ni??o events could limit primate reproductive output, threatening the persistence and recovery of ateline primate populations. ?? 2011 Blackwell Publishing Ltd.

  2. Development of new techniques of using irradiation in the genetic improvement of warm season grasses and an assessment of the genetic and cytogenetic effects. Annual report, August 1, 1976--October 31, 1977

    International Nuclear Information System (INIS)

    Burton, G.W.; Hanna, W.W.

    1977-08-01

    New techniques of using irradiation in the genetic improvement of several warm season grasses are described. The economic value of radiation induced plant mutants and the genetic and cytogenetic effects of these treatments are discussed. Alterations in protein quality in pearl millet grain and improved varieties of Bermuda grass following radiation treatment are reported

  3. Non-linear Feedbacks Between Forest Mortality and Climate Change: Implications for Snow Cover, Water Resources, and Ecosystem Recovery in Western North America (Invited)

    Science.gov (United States)

    Brooks, P. D.; Harpold, A. A.; Biederman, J. A.; Gochis, D. J.; Litvak, M. E.; Ewers, B. E.; Broxton, P. D.; Reed, D. E.

    2013-12-01

    Unprecedented levels of tree mortality from insect infestation and wildfire are dramatically altering forest structure and composition in Western North America. Warming temperatures and increased drought stress have been implicated as major factors in the increasing spatial extent and frequency of these forest disturbances, but it is unclear how these changes in forest structure will interact with ongoing climate change to affect snowmelt water resources either for society or for ecosystem recovery following mortality. Because surface discharge, groundwater recharge, and ecosystem productivity all depend on seasonal snowmelt, a critical knowledge gap exists not only in predicting discharge, but in quantifying spatial and temporal variability in the partitioning of snowfall into abiotic vapor loss, plant available water, recharge, and streamflow within the complex mosaic of forest disturbance and topography that characterizes western mountain catchments. This presentation will address this knowledge gap by synthesizing recent work on snowpack dynamics and ecosystem productivity from seasonally snow-covered forests along a climate gradient from Arizona to Wyoming; including undisturbed sites, recently burned forests, and areas of extensive insect-induced forest mortality. Both before-after and control-impacted studies of forest disturbance on snow accumulation and ablation suggest that the spatial scale of snow distribution increases following disturbance, but net snow water input in a warming climate will increase only in topographically sheltered areas. While forest disturbance changes spatial scale of snowpack partitioning, the amount and especially the timing of snow cover accumulation and ablation are strongly related to interannual variability in ecosystem productivity with both earlier snowmelt and later snow accumulation associated with decreased carbon uptake. Empirical analyses and modeling are being developed to identify landscapes most sensitive to

  4. Seasonal Patterns of Sporophyte Growth, Fertility, Fouling, and Mortality of Saccharina latissima in Skagerrak, Norway: Implications for Forest Recovery

    Directory of Open Access Journals (Sweden)

    Guri Sogn Andersen

    2011-01-01

    Full Text Available On the Skagerrak coast the kelp Saccharina latissima has suffered severe stand reductions over the last decade, resulting in loss of important habitats. In the present study, healthy kelp plants were transplanted into four deforested areas and their patterns of growth, reproduction, and survival were monitored through subsequent seasons. Our main objective was to establish whether the kelp plants were able to grow and mature in deforested areas. We observed normal patterns of growth and maturation at all study sites. However, heavy fouling by epiphytes occurred each summer, followed by high kelp mortality. The study shows that the seasonal variations and the life stage timing of S. latissima make formation of self-sustainable populations impossible in the present environment. Most noteworthy, we suggest that fouling by epiphytes is involved in the lack of kelp forest recovery in Skagerrak, Norway.

  5. Temperature as a potent driver of regional forest drought stress and tree mortality

    Science.gov (United States)

    Williams, A. Park; Allen, Craig D.; Macalady, Alison K.; Griffin, Daniel; Woodhouse, Connie A.; Meko, David M.; Swetnam, Thomas W.; Rauscher, Sara A.; Seager, Richard; Grissino-Mayer, Henri D.; Dean, Jeffrey S.; Cook, Edward R.; Gangodagamage, Chandana; Cai, Michael; McDowell, Nathan G.

    2012-01-01

    s the climate changes, drought may reduce tree productivity and survival across many forest ecosystems; however, the relative influence of specific climate parameters on forest decline is poorly understood. We derive a forest drought-stress index (FDSI) for the southwestern United States using a comprehensive tree-ring data set representing AD 1000-2007. The FDSI is approximately equally influenced by the warm-season vapour-pressure deficit (largely controlled by temperature) and cold-season precipitation, together explaining 82% of the FDSI variability. Correspondence between the FDSI and measures of forest productivity, mortality, bark-beetle outbreak and wildfire validate the FDSI as a holistic forest-vigour indicator. If the vapour-pressure deficit continues increasing as projected by climate models, the mean forest drought-stress by the 2050s will exceed that of the most severe droughts in the past 1,000 years. Collectively, the results foreshadow twenty-first-century changes in forest structures and compositions, with transition of forests in the southwestern United States, and perhaps water-limited forests globally, towards distributions unfamiliar to modern civilization.

  6. Investigation on seasonal variation of thermal-induced strain in flexible pavements based on field and laboratory measurements

    Directory of Open Access Journals (Sweden)

    Simita Biswas

    2016-09-01

    Full Text Available Pavement temperature variation has a large influence on the structural response of flexible pavements. Daily and seasonal temperature fluctuation causes expansion and contraction of pavement material, which then leads to the generation of thermal strain. In this study, field observation and laboratory tests were conducted to investigate seasonal variation of thermal-induced strain in flexible pavement. Field observations were conducted at the Integrated Road Research Facility (IRRF’s test road in Edmonton, Alberta, Canada, which is fully equipped with structural and environmental monitoring instruments. The main objective of the field study was to compare the variation of thermal-induced strain in warm and cold seasons. Field results indicated that thermal-induced strain is 1.4–2.0 times greater in cold seasons than in warm seasons following the same pavement temperature variations; however, strain generation rate was greater in warm seasons. Laboratory testing of asphalt slab and cylindrical samples produced comparable ratios. Moreover, field observation and laboratory testing showed a similar trend of temperature and thermal strain variations. Keywords: Thermal-induced strain, Asphalt strain gauge, Field observation, Flexible pavement, Laboratory testing, Seasonal variation

  7. 0-6613 : evaluate binder and mixture aging for warm mix asphalt.

    Science.gov (United States)

    2013-08-01

    Warm mix asphalt (WMA) technologies employ reduced : mixing and placement temperatures, thereby allowing : reduced fuel consumption, enhanced compaction, : increased haul distances, and an extended paving : season. However, there have been issues of ...

  8. Scaling Potential Evapotranspiration with Greenhouse Warming (Invited)

    Science.gov (United States)

    Scheff, J.; Frierson, D. M.

    2013-12-01

    Potential evapotranspiration (PET) is a supply-independent measure of the evaporative demand of a terrestrial climate, of basic importance in climatology, hydrology, and agriculture. Future increases in PET from greenhouse warming are often cited as key drivers of global trends toward drought and aridity. The present work computes recent and business-as-usual-future Penman-Monteith (i.e. physically-based) PET fields at 3-hourly resolution in 14 modern global climate models. The %-change in local annual-mean PET over the upcoming century is almost always positive, modally low double-digit in magnitude, usually increasing with latitude, yet quite divergent between models. These patterns are understood as follows. In every model, the global field of PET %-change is found to be dominated by the direct, positive effects of constant-relative-humidity warming (via increasing vapor pressure deficit and increasing Clausius-Clapeyron slope.) This direct-warming term very accurately scales as the PET-weighted (warm-season daytime) local warming, times 5-6% per degree (related to the Clausius-Clapeyron equation), times an analytic factor ranging from about 0.25 in warm climates to 0.75 in cold climates, plus a small correction. With warming of several degrees, this product is of low double-digit magnitude, and the strong temperature dependence gives the latitude dependence. Similarly, the inter-model spread in the amount of warming gives most of the spread in this term. Additional spread in the total change comes from strong disagreement on radiation, relative-humidity, and windspeed changes, which make smaller yet substantial contributions to the full PET %-change fields.

  9. Linkage Between Hourly Precipitation Events and Atmospheric Temperature Changes over China during the Warm Season

    Science.gov (United States)

    Miao, Chiyuan; Sun, Qiaohong; Borthwick, Alistair G. L.; Duan, Qingyun

    2016-01-01

    We investigated changes in the temporospatial features of hourly precipitation during the warm season over mainland China. The frequency and amount of hourly precipitation displayed latitudinal zonation, especially for light and moderate precipitation, which showed successive downward change over time in northeastern and southern China. Changes in the precipitation amount resulted mainly from changes in frequency rather than changes in intensity. We also evaluated the linkage between hourly precipitation and temperature variations and found that hourly precipitation extreme was more sensitive to temperature than other categories of precipitation. A strong dependency of hourly precipitation on temperature occurred at temperatures colder than the median daily temperature; in such cases, regression slopes were greater than the Clausius-Clapeyron (C-C) relation of 7% per degree Celsius. Regression slopes for 31.6%, 59.8%, 96.9%, and 99.1% of all stations were greater than 7% per degree Celsius for the 75th, 90th, 99th, and 99.9th percentiles for precipitation, respectively. The mean regression slopes within the 99.9th percentile of precipitation were three times the C-C rate. Hourly precipitation showed a strong negative relationship with daily maximum temperature and the diurnal temperature range at most stations, whereas the equivalent correlation for daily minimum temperature was weak. PMID:26931350

  10. [Effects of diurnal warming on soil N2O emission in soybean field].

    Science.gov (United States)

    Hu, Zheng-Hua; Zhou, Ying-Ping; Cui, Hai-Ling; Chen, Shu-Tao; Xiao, Qi-Tao; Liu, Yan

    2013-08-01

    To investigate the impact of experimental warming on N2O emission from soil of soybean field, outdoor experiments with simulating diurnal warming were conducted, and static dark chamber-gas chromatograph method was used to measure N2O emission fluxes. Results indicated that: the diurnal warming did not change the seasonal pattern of N2O emissions from soil. In the whole growing season, comparing to the control treatment (CK), the warming treatment (T) significantly enhanced the N2O flux and the cumulative amount of N2O by 17.31% (P = 0.019), and 20.27% (P = 0.005), respectively. The significant correlations were found between soil N2O emission and soil temperature, moisture. The temperature sensitivity values of soil N2O emission under CK and T treatments were 3.75 and 4.10, respectively. In whole growing stage, T treatment significantly increased the crop aboveground and total biomass, the nitrate reductase activity, and total nitrogen in leaves, while significantly decreased NO3(-) -N content in leaves. T treatment significantly increased soil NO3(-) -N content, but had no significant effect on soil organic carbon and total nitrogen contents. The results of this study suggested that diurnal warming enhanced N2O emission from soil in soybean field.

  11. Cold season emissions dominate the Arctic tundra methane budget

    Science.gov (United States)

    Zona, Donatella; Gioli, Beniamino; Commane, Róisín; Lindaas, Jakob; Wofsy, Steven C.; Miller, Charles E.; Dinardo, Steven J.; Dengel, Sigrid; Sweeney, Colm; Karion, Anna; Chang, Rachel Y.-W.; Henderson, John M.; Murphy, Patrick C.; Goodrich, Jordan P.; Moreaux, Virginie; Liljedahl, Anna; Watts, Jennifer D.; Kimball, John S.; Lipson, David A.; Oechel, Walter C.

    2016-01-01

    Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y-1, ∼25% of global emissions from extratropical wetlands, or ∼6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.

  12. Trend and Seasonal Patterns of Injuries and Mortality Due to Motorcyclists Traffic Accidents; A Hospital-Based Study.

    Science.gov (United States)

    Hosseinpour, Marjan; Mohammadian-Hafshejani, Abdollah; Esmaeilpour Aghdam, Mohammad; Mohammadian, Mahdi; Maleki, Farzad

    2017-01-01

    To investigate trend and seasonal pattern of occurrence and mortality of motorcycle accidents in patients referred to hospitals of Isfahan. This cross-sectional study was carried out using traffic accidents data of Isfahan province, extracted from Ministry of Health (MOH) database from 2006 to 2010. During the study period, 83648 people injured due to motorcycle traffic accidents were referred to hospitals, all of them entered in the study. Logistic regression model was used to calculate the hospital mortality odds ratio, and Cochrane-Armitage test was used for assessment of linear trend. During the study period, the hospital admission for motorcycle accident was 83,648 and 89.3% (74743) of them were men. Mean age in accidents time was 26.41±14.3 years. The injuries and death sex ratio were 8.4 and 16.9, respectively. Lowest admission rate was during autumn and highest during summer. The injury mortality odds ratio was 1.01 (CI 95% 0.73-1.39) in the Spring, 1.34 (CI95% 1.01-1.79) in summer and 1.17 (CI95% 0.83-1.63). It was also calculated to be 2.51 (CI95% 1.36-4.64) in age group 40-49, 2.39 (CI95% 1.51-5.68) in 50-59 and 4.79 (CI95% 2.49-9.22) in 60-69 years. The mortality odds ratio was 3.53 (CI95% 2.77-4.5) in rural place, 1.33 (CI95% 1.15-1.54) in men, and 2.44 (CI95% 2.09-2.85) in the road out of town and village. In addition, trend of motorcycle accidents mortality was increasing ( p accidents injuries are more common in men, summer, young age and rural roads. These high risk groups need more attention, care and higher training.

  13. Seasonal soil moisture patterns in contrasting habitats in the Willamette Valley, Oregon

    Science.gov (United States)

    Changing seasonal soil moisture regimes caused by global warming may alter plant community composition in sensitive habitats such as wetlands and oak savannas. To evaluate such changes, an understanding of typical seasonal soil moisture regimes is necessary. The primary objective...

  14. Seasonal and inter-annual temperature variability in the bottom waters over the western Black Sea shelf

    Directory of Open Access Journals (Sweden)

    G. I. Shapiro

    2011-09-01

    Full Text Available Long-term changes in the state of the Bottom Shelf Water (BSW on the Western shelf of the Black Sea are assessed using analysis of intra-seasonal and inter-annual temperature variations. For the purpose of this study the BSW is defined as such shelf water mass between the seabed and the upper mixed layer (bounded by the σθ = 14.2 isopycnal which has limited ability to mix vertically with oxygen-rich surface waters during the warm season due to formation of a seasonal pycnocline. A long-term time series of temperature anomalies in the BSW is constructed from in-situ observations taken over the 2nd half of the 20th century. The BSW is shown to occupy nearly half of the shelf area during the summer stratification period (May–November.The results reveal a warm phase in the 1960s/70s, followed by a cold phase between 1985 and 1995 and a further warming after 1995. The transition between the warm and cold periods coincides with a regime shift in the Black Sea ecosystem. While it was confirmed that the memory of winter convection is well preserved over the following months in the deep sea, the signal of winter cooling in the BSW significantly reduces during the warm season. The potential of the BSW to ventilate horizontally during the warm season with the deep-sea waters is assessed using isopycnic analysis of temperature variations. It is shown that temperature in the BSW is stronger correlated with the temperature of Cold Intermediate Waters (CIW in the deep sea than with the severity of the previous winters, thus indicating that the isopycnal exchanges with the deep sea are more important for inter-annual/inter-decadal variability of the BSW on the western Black Sea shelf than effects of winter convection on the shelf itself.

  15. Range shifts and global warming: ecological responses of Empetrum nigrum L. to experimental warming at its northern (high Arctic) and southern (Atlantic) geographical range margin

    International Nuclear Information System (INIS)

    Buizer, Bert; Weijers, Stef; Van Bodegom, Peter M; Van Breda, Johan; De Korte, Maarten; Van Rijckevorsel, Jaap; Rozema, Jelte; Alsos, Inger Greve; Eidesen, Pernille Bronken

    2012-01-01

    Global change is expected to lead to range shifts of plant species. The ecological mechanisms underpinning these shifts are currently not well understood. Here, we compared ecological responses possibly underlying southern range contraction and northern range expansion of Empetrum nigrum, a key species in northern heathlands, which may be related to global change. We hypothesized a negative response to warming in the ‘south’ (i.e. the Netherlands) and a positive response at the northern range margin (the tundra on Svalbard). Open top chambers (OTCs) were used to simulate global warming. In the ‘south’, OTC warming caused enhanced shoot growth and growth rate, biomass increment, advanced phenology, larger and heavier berries of Empetrum, while its growing season was extended by 75 days. Under OTC warming co-occurring Calluna vulgaris also showed an increased growing season length (by 98 days) as well as increased shoot growth rate and biomass growth, plant cover and height. Still, we found no evidence for increased competitiveness relative to Empetrum. In the ‘north’, Empetrum responded with increased shoot and biomass growth, enhanced berry development and ripening to warming. These responses exceeded those of co-occurring Cassiope tetragona with the exception of its biomass response. The direct and indirect ecological responses found do not readily explain the observed northward retreat of Empetrum at the southern range margin. The direct ecological responses found at its northern range margin are, on the other hand, in line with the increased occurrences of this species on Svalbard. (letter)

  16. A novel visualisation tool for climate services: a case study of temperature extremes and human mortality in Europe

    Science.gov (United States)

    Lowe, R.; Ballester, J.; Robine, J.; Herrmann, F. R.; Jupp, T. E.; Stephenson, D.; Rodó, X.

    2013-12-01

    Users of climate information often require probabilistic information on which to base their decisions. However, communicating information contained within a probabilistic forecast presents a challenge. In this paper we demonstrate a novel visualisation technique to display ternary probabilistic forecasts on a map in order to inform decision making. In this method, ternary probabilistic forecasts, which assign probabilities to a set of three outcomes (e.g. low, medium, and high risk), are considered as a point in a triangle of barycentric coordinates. This allows a unique colour to be assigned to each forecast from a continuum of colours defined on the triangle. Colour saturation increases with information gain relative to the reference forecast (i.e. the long term average). This provides additional information to decision makers compared with conventional methods used in seasonal climate forecasting, where one colour is used to represent one forecast category on a forecast map (e.g. red = ';dry'). We use the tool to present climate-related mortality projections across Europe. Temperature and humidity are related to human mortality via location-specific transfer functions, calculated using historical data. Daily mortality data at the NUTS2 level for 16 countries in Europe were obtain from 1998-2005. Transfer functions were calculated for 54 aggregations in Europe, defined using criteria related to population and climatological similarities. Aggregations are restricted to fall within political boundaries to avoid problems related to varying adaptation policies between countries. A statistical model is fit to cold and warm tails to estimate future mortality using forecast temperatures, in a Bayesian probabilistic framework. Using predefined categories of temperature-related mortality risk, we present maps of probabilistic projections for human mortality at seasonal to decadal time scales. We demonstrate the information gained from using this technique compared to more

  17. Responses of Ecosystem CO2 Fluxes to Short-Term Experimental Warming and Nitrogen Enrichment in an Alpine Meadow, Northern Tibet Plateau

    Science.gov (United States)

    Shi, Peili; Jiang, Jing; Song, Minghua; Xiong, Dingpeng; Ma, Weiling; Fu, Gang; Zhang, Xianzhou; Shen, Zhenxi

    2013-01-01

    Over the past decades, the Tibetan Plateau has experienced pronounced warming, yet the extent to which warming will affect alpine ecosystems depends on how warming interacts with other influential global change factors, such as nitrogen (N) deposition. A long-term warming and N manipulation experiment was established to investigate the interactive effects of warming and N deposition on alpine meadow. Open-top chambers were used to simulate warming. N addition, warming, N addition × warming, and a control were set up. In OTCs, daytime air and soil temperature were warmed by 2.0°C and 1.6°C above ambient conditions, but soil moisture was decreased by 4.95 m3 m−3. N addition enhanced ecosystem respiration (Reco); nevertheless, warming significantly decreased Reco. The decline of Reco resulting from warming was cancelled out by N addition in late growing season. Our results suggested that N addition enhanced Reco by increasing soil N availability and plant production, whereas warming decreased Reco through lowering soil moisture, soil N supply potential, and suppression of plant activity. Furthermore, season-specific responses of Reco indicated that warming and N deposition caused by future global change may have complicated influence on carbon cycles in alpine ecosystems. PMID:24459432

  18. Identification of a seasonal pattern to brain metastases

    Directory of Open Access Journals (Sweden)

    Sakellakis M

    2016-03-01

    Full Text Available Minas Sakellakis,1 Angelos Koutras,1 Maria Pittaka,2 Dimitrios Kardamakis,2 Melpomeni Kalofonou,1 Haralabos P Kalofonos,1 Despina Spyropoulou2 1Division of Oncology, Department of Medicine, 2Department of Radiation Oncology, University Hospital, Patras Medical School, Rion, Patras, GreeceWe have previously tested our hypothesis that there is a seasonality in the incidence of carcinomatous meningitis.1 Although further validation is needed in a larger cohort, we found that leptomeningeal metastasis occurred more often during warm months of the year which, in the case of Greece, is the period generally marked with the larger daytime length.1 Carcinomatous meningitis is closely related to brain metastasis, and a logical question is whether warm season is marked by a greater propensity also for brain metastasis.2 

  19. Global warming: it's not only size that matters

    Science.gov (United States)

    Hegerl, Gabriele C.

    2011-09-01

    impacts than temperatures that have occurred frequently due to internal climate variability. Determining when exactly temperatures enter unusual ranges may be done in many different ways (and the paper shows several, and more could be imagined), but the main result of first local emergence in low latitudes remains robust. A worrying factor is that the regions where the signal is expected to emerge first, or is already emerging are largely regions in Africa, parts of South and Central America, and the Maritime Continent; regions that are vulnerable to climate change for a variety of regions (see IPCC 2007), and regions which contribute generally little to global greenhouse gas emissions. In contrast, strong emissions of greenhouse gases occur in regions of low warming-to-variability ratio. To get even closer to the relevance of this finding for impacts, it would be interesting to place the emergence of highly unusual summer temperatures in the context not of internal variability, but in the context of variability experienced by the climate system prior to the 20th century, as, e.g. documented in palaeoclimatic reconstructions and simulated in simulations of the last millennium (see Jansen et al 2007). External forcing has moved the temperature range around more strongly for some regions and in some seasons than others. For example, while reconstructions of summer temperatures in Europe appear to show small long-term variations, winter shows deep drops in temperature in the little Ice Age and a long-term increase since then (Luterbacher et al 2004), which was at least partly caused by external forcing (Hegerl et al 2011a) and therefore 'natural variability' may be different from internal variability. A further interesting question in attempts to provide a climate-based proxy for impacts of climate change is: to what extent does the rapidity of change matter, and how does it compare to trends due to natural variability? It is reasonable to assume that fast changes impact

  20. A farm-level analysis of economic and agronomic impacts of gradual climate warming

    International Nuclear Information System (INIS)

    Kaiser, H.M.; Sampath, R.; Riha, S.J.; Wilks, D.S.; Rossiter, D.G.

    1993-01-01

    The potential economic and agronomic impacts of gradual climate warming are examined at the farm level. Three models of the relevant climatic, agronomic, and economic processes are developed and linked to address climate change impacts and agricultural adaptability. Several climate warming severity. The results indicate that grain farmers in southern Minnesota can effectively adapt to a gradually changing climate (warmer and either wetter or drier) by adopting later maturing cultivars, changing crop mix, and altering the timing of field operations to take advantage of a longer growing season resulting from climate warming

  1. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems.

    Science.gov (United States)

    Hicks Pries, Caitlin E; van Logtestijn, Richard S P; Schuur, Edward A G; Natali, Susan M; Cornelissen, Johannes H C; Aerts, Rien; Dorrepaal, Ellen

    2015-12-01

    Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change feedback. Few studies partitioning ecosystem respiration examine decadal warming effects or compare responses among ecosystems. Here, we first examined how 11 years of warming during different seasons affected autotrophic and heterotrophic respiration in a bryophyte-dominated peatland in Abisko, Sweden. We used natural abundance radiocarbon to partition ecosystem respiration into autotrophic respiration, associated with production, and heterotrophic decomposition. Summertime warming decreased the age of carbon respired by the ecosystem due to increased proportional contributions from autotrophic and young soil respiration and decreased proportional contributions from old soil. Summertime warming's large effect was due to not only warmer air temperatures during the growing season, but also to warmer deep soils year-round. Second, we compared ecosystem respiration responses between two contrasting ecosystems, the Abisko peatland and a tussock-dominated tundra in Healy, Alaska. Each ecosystem had two different timescales of warming (permafrost ecosystems. © 2015 John Wiley & Sons Ltd.

  2. Seasonal evolution of faecal egg output by gastrointestinal worms in goats on communal farms in eastern Namibia

    Directory of Open Access Journals (Sweden)

    F.F. Kumba

    2003-11-01

    Full Text Available As a more detailed continuation of a previous study, faecal samples for worm egg counts were collected per rectum from ten marked adult animals in selected flocks of goats, in each of six villages evenly spread out in the communal farming district of Okakarara in eastern Namibia. The study was conducted on a monthly basis from August 1999 to July 2000. Average faecal worm egg counts (FECs were highest during the warm-wet season, much lower during the cold-dry months and moderate during the hot-dry season. Least square means of FECs were 2 140, 430 and 653 per gram of faeces for the three seasons, respectively. Seasonal variation in egg counts was significant (P < 0.0001. Gastrointestinal strongyles, and to a lesser extent Strongyloides species, were the predominant parasite groups identified in goats. Kidding rates peaked in the cold-dry season and mortality rates in the hot-dry season. Results of this study suggest that gastrointestinal parasitism may be a problem that accentuates the effect of poor nutrition on small ruminants during the season of food shortages in the east of Namibia and that the use of FECs per se to assess the severity of gastrointestinal parasitic infection in goats followed by chemoprophylactic strategic and / or tactical treatment, may not be the best approach to addressing the worm problem under resource-poor conditions. The use of the FAMACHA(c system that identifies severely affected animals for treatment is technically a better option for communal farmers.

  3. Global warming and mass mortalities of benthic invertebrates in the Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Irene Rivetti

    Full Text Available Satellite data show a steady increase, in the last decades, of the surface temperature (upper few millimetres of the water surface of the Mediterranean Sea. Reports of mass mortalities of benthic marine invertebrates increased in the same period. Some local studies interpreted the two phenomena in a cause-effect fashion. However, a basin-wide picture of temperature changes combined with a systematic assessment on invertebrate mass mortalities was still lacking. Both the thermal structure of the water column in the Mediterranean Sea over the period 1945-2011 and all documented invertebrate mass mortality events in the basin are analysed to ascertain if: 1- documented mass mortalities occurred under conditions of positive temperature trends at basin scale, and 2- atypical thermal conditions were registered at the smaller spatial and temporal scale of mass mortality events. The thermal structure of the shallow water column over the last 67 years was reconstructed using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS programme. A review of the mass mortality events of benthic invertebrates at Mediterranean scale was also carried out. The analysis of in situ temperature profiles shows that the Mediterranean Sea changed in a non-homogeneous fashion. The frequency of mass mortalities is increasing. The areas subjected to these events correspond to positive thermal anomalies. Statistically significant temperature trends in the upper layers of the Mediterranean Sea show an increase of up to 0.07°C/yr for a large fraction of the basin. Mass mortalities are consistent with both the temperature increase at basin scale and the thermal changes at local scale, up to 5.2°C. Our research supports the existence of a causal link between positive thermal anomalies and observed invertebrate mass mortalities in the Mediterranean Sea, invoking focused mitigation initiatives in sensitive areas.

  4. Global Warming and Mass Mortalities of Benthic Invertebrates in the Mediterranean Sea

    Science.gov (United States)

    Rivetti, Irene; Fraschetti, Simonetta; Lionello, Piero; Zambianchi, Enrico; Boero, Ferdinando

    2014-01-01

    Satellite data show a steady increase, in the last decades, of the surface temperature (upper few millimetres of the water surface) of the Mediterranean Sea. Reports of mass mortalities of benthic marine invertebrates increased in the same period. Some local studies interpreted the two phenomena in a cause-effect fashion. However, a basin-wide picture of temperature changes combined with a systematic assessment on invertebrate mass mortalities was still lacking. Both the thermal structure of the water column in the Mediterranean Sea over the period 1945–2011 and all documented invertebrate mass mortality events in the basin are analysed to ascertain if: 1- documented mass mortalities occurred under conditions of positive temperature trends at basin scale, and 2- atypical thermal conditions were registered at the smaller spatial and temporal scale of mass mortality events. The thermal structure of the shallow water column over the last 67 years was reconstructed using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS programme. A review of the mass mortality events of benthic invertebrates at Mediterranean scale was also carried out. The analysis of in situ temperature profiles shows that the Mediterranean Sea changed in a non-homogeneous fashion. The frequency of mass mortalities is increasing. The areas subjected to these events correspond to positive thermal anomalies. Statistically significant temperature trends in the upper layers of the Mediterranean Sea show an increase of up to 0.07°C/yr for a large fraction of the basin. Mass mortalities are consistent with both the temperature increase at basin scale and the thermal changes at local scale, up to 5.2°C. Our research supports the existence of a causal link between positive thermal anomalies and observed invertebrate mass mortalities in the Mediterranean Sea, invoking focused mitigation initiatives in sensitive areas. PMID:25535973

  5. Soil warming for utilization and dissipation of waste heat in Pennsylvania

    International Nuclear Information System (INIS)

    DeWalle, D.R.; Chapura, A.M. Jr.

    1978-01-01

    The feasibility of using soil warming for utilization and dissipation of reject heat from power plants was demonstrated in a year-long test operation of a field prototype in Pennsylvania. A parallel network of 5-mm-diam polyethylene pipes was buried at a 0.3-m depth and with 0.6-m spacing in the soil covering a 15- x 60-m area to convey hot water simulating condenser cooling water from a power plant. Crop response to the heated soil varied: Snap beans and warm season forage crops such as sudangrass responded with increased yields, while cool season forage crops experienced decreased yields. Winter wheat yields were also increased, but winter barley was winter-killed due to delayed development of cold tolerance in the warm soil. Heat dissipation from the buried pipes was primarily by thermal conduction to the soil surface. Rates of heat loss from the buried pipes were most accurately predicted using an equation that included an explicit term for heat conduction below the pipes. Estimated soil warming land area necessary to dissipate all the reject heat from a 33% efficiency, 1500-MW electrical power plant based on minimum measured summer heat loss rates was 76 km 2 compared to the economic optimum of 18.2 km 2 determined as the least-cost system

  6. Seasonal mortality and sequential density dependence in a migratory bird

    NARCIS (Netherlands)

    Rakhimberdiev, Eldar; van den Hout, Piet J.; Brugge, Maarten; Spaans, Bernard; Piersma, Theunis

    2015-01-01

    Migratory bird populations may be limited during one or more seasons, and thus at one or more places, but there is a dearth of empirical examples of this possibility. We analyse seasonal survival in a migratory shellfish-eating shorebird (red knot Calidris canutus islandica) during a series of years

  7. Changes in Intense Precipitation Events in West Africa and the central U.S. under Global Warming

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Kerry H. [Univ. of Texas, Austin, TX (United States); Vizy, Edward [Univ. of Texas, Austin, TX (United States)

    2016-02-08

    The purpose of the proposed project is to improve our understanding of the physical processes and large-scale connectivity of changes in intense precipitation events (high rainfall rates) under global warming in West Africa and the central U.S., including relationships with low-frequency modes of variability. This is in response to the requested subject area #2 “simulation of climate extremes under a changing climate … to better quantify the frequency, duration, and intensity of extreme events under climate change and elucidate the role of low frequency climate variability in modulating extremes.” We will use a regional climate model and emphasize an understanding of the physical processes that lead to an intensification of rainfall. The project objectives are as follows: 1. Understand the processes responsible for simulated changes in warm-season rainfall intensity and frequency over West Africa and the Central U.S. associated with greenhouse gas-induced global warming 2. Understand the relationship between changes in warm-season rainfall intensity and frequency, which generally occur on regional space scales, and the larger-scale global warming signal by considering modifications of low-frequency modes of variability. 3. Relate changes simulated on regional space scales to global-scale theories of how and why atmospheric moisture levels and rainfall should change as climate warms.

  8. BVOCs emission in a semi-arid grassland under climate warming and nitrogen deposition

    Directory of Open Access Journals (Sweden)

    H. J. Wang

    2012-04-01

    Full Text Available Biogenic volatile organic compounds (BVOCs profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field experiment in a semi-arid grassland (Inner Mongolia, China to examine the emission and the responses of BVOCs emissions to warming and nitrogen deposition. The natural emission rate (NER of monoterpene (dominant BVOCs here is 107 ± 16 μg m−2 h−1 in drought 2007, and 266 ± 53 μg m−2 h−1 in wet 2008, respectively. Warming decreased the standard emission factor (SEF by 24% in 2007, while it increased by 43% in 2008. The exacerbated soil moisture loss caused by warming in dry season might be responsible for the decrease of SEF in 2007. A possible threshold of soil moisture (8.2% (v/v, which controls the direction of warming effects on monoterpene emission, existed in the semiarid grassland. Nitrogen deposition decreased the coverage of Artemisia frigida and hence reduced the NER by 24% across the two growing seasons. These results suggest that the grasslands dominated by the extended Artemisia frigida are an important source for BVOCs, while the responses of their emissions to global changes are more uncertain since they depend on multifactorial in-situ conditions.

  9. Seasonal trends of atmospheric nitrogen dioxide and sulfur dioxide over North Santa Clara, Cuba.

    Science.gov (United States)

    Alejo, Daniellys; Morales, Mayra C; de la Torre, Jorge B; Grau, Ricardo; Bencs, László; Van Grieken, René; Van Espen, Piet; Sosa, Dismey; Nuñez, Vladimir

    2013-07-01

    Atmospheric nitrogen dioxide (NO2) and sulfur dioxide (SO2) levels were monitored simultaneously by means of Radiello passive samplers at six sites of Santa Clara city, Cuba, in the cold and the warm seasons in 2010. The dissolved ionic forms of NO2 and SO2 as nitrate and sulfite plus sulfate, respectively, were determined by means of ion chromatography. Analysis of NO2 as nitrite was also performed by UV-Vis spectrophotometry. For NO2, significant t tests show good agreement between the results of IC and UV-Vis methods. The NO2 and SO2 concentrations peaked in the cold season, while their minimum levels were experienced in the warm season. The pollutant levels do not exceed the maximum allowable limit of the Cuban Standard 39:1999, i.e., 40 μg/m(3) and 50 μg/m(3) for NO2 and SO2, respectively. The lowest pollutant concentrations obtained in the warm season can be attributed to an increase in their removal via precipitation (scavenging) while to the decreased traffic density and industrial emission during the summer holidays (e.g., July and August).

  10. Seasonal variability of rocky reef fish assemblages: Detecting functional and structural changes due to fishing effects

    Science.gov (United States)

    Henriques, Sofia; Pais, Miguel Pessanha; Costa, Maria José; Cabral, Henrique Nogueira

    2013-05-01

    The present study analyzed the effects of seasonal variation on the stability of fish-based metrics and their capability to detect changes in fish assemblages, which is yet poorly understood despite the general idea that guilds are more resilient to natural variability than species abundances. Three zones subject to different levels of fishing pressure inside the Arrábida Marine Protected Area (MPA) were sampled seasonally. The results showed differences between warm (summer and autumn) and cold (winter and spring) seasons, with the autumn clearly standing out. In general, the values of the metrics density of juveniles, density of invertebrate feeders and density of omnivores increased in warm seasons, which can be attributed to differences in recruitment patterns, spawning migrations and feeding activity among seasons. The density of generalist/opportunistic individuals was sensitive to the effect of fishing, with higher values at zones with the lowest level of protection, while the density of individuals with high commercial value only responded to fishing in the autumn, due to a cumulative result of both juveniles and adults abundances during this season. Overall, this study showed that seasonal variability affects structural and functional features of the fish assemblage and that might influence the detection of changes as a result of anthropogenic pressures. The choice of a specific season, during warm sea conditions after the spawning period (July-October), seems to be more adequate to assess changes on rocky-reef fish assemblages.

  11. Effects of in situ climate warming on monarch caterpillar (Danaus plexippus development

    Directory of Open Access Journals (Sweden)

    Nathan P. Lemoine

    2015-10-01

    Full Text Available Climate warming will fundamentally alter basic life history strategies of many ectothermic insects. In the lab, rising temperatures increase growth rates of lepidopteran larvae but also reduce final pupal mass and increase mortality. Using in situ field warming experiments on their natural host plants, we assessed the impact of climate warming on development of monarch (Danaus plexippus larvae. Monarchs were reared on Asclepias tuberosa grown under ‘Ambient’ and ‘Warmed’ conditions. We quantified time to pupation, final pupal mass, and survivorship. Warming significantly decreased time to pupation, such that an increase of 1 °C corresponded to a 0.5 day decrease in pupation time. In contrast, survivorship and pupal mass were not affected by warming. Our results indicate that climate warming will speed the developmental rate of monarchs, influencing their ecological and evolutionary dynamics. However, the effects of climate warming on larval development in other monarch populations and at different times of year should be investigated.

  12. Boreal and temperate trees show strong acclimation of respiration to warming.

    Science.gov (United States)

    Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

    2016-03-31

    Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

  13. Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions.

    Science.gov (United States)

    Moyes, Andrew B; Germino, Matthew J; Kueppers, Lara M

    2015-09-01

    Climate change is altering plant species distributions globally, and warming is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with warming difficult to predict. We measured response functions linking carbon (C) assimilation and temperature- and moisture-related microclimatic factors for limber pine (Pinus flexilis) seedlings growing in a heating × watering experiment within and above the alpine treeline. We then extrapolated these response functions using observed microclimate conditions to estimate the net effects of warming and associated soil drying on C assimilation across an entire growing season. Moisture and temperature limitations were each estimated to reduce potential growing season C gain from a theoretical upper limit by 15-30% (c. 50% combined). Warming above current treeline conditions provided relatively little benefit to modeled net assimilation, whereas assimilation was sensitive to either wetter or drier conditions. Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as seasonally dry subalpine and alpine ecosystems continue to warm. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  14. Scrub typhus in Uttarakhand & adjoining Uttar Pradesh: Seasonality, clinical presentations & predictors of mortality.

    Science.gov (United States)

    Bhargava, Anurag; Kaushik, Reshma; Kaushik, Rajeev Mohan; Sharma, Anita; Ahmad, Sohaib; Dhar, Minakshi; Mittal, Garima; Khanduri, Sushant; Pant, Priyannk; Kakkar, Rajesh

    2016-12-01

    Scrub typhus is a re-emerging mite-borne rickettsiosis, which continues to be underdiagnosed, with lethal consequences. The present study was conducted to determine the seasonality, clinical presentation and predictors of mortality in patients with scrub typhus at a tertiary care teaching hospital in northern India. Scrub typhus was suspected in patients attending the hospital as per the standard case definition and serological evidence was obtained by performing an IgM ELISA. A total of 284 patients with scrub typhus from urban and rural areas were seen, predominantly from July to November. The most common clinical presentation was a bilateral community-acquired pneumonia (CAP), which resembled pneumonia due to atypical pathogens and often progressed to acute respiratory distress syndrome (ARDS). An acute undifferentiated febrile illness (AUFI) or a febrile illness associated with altered sensorium, aseptic meningitis, shock, abdominal pain, gastrointestinal bleeding or jaundice was also seen. Eschars were seen in 17 per cent of patients, and thrombocytopenia, transaminitis and azotaemia were frequent. There were 24 deaths (8.5%) caused predominantly by ARDS and multi-organ dysfunction. The mortality in patients with ARDS was high (37%). ARDS [odds ratio (OR)=38.29, 95% confidence interval (CI): 9.93, 147.71] and acute kidney injury (OR=8.30, 95% CI: 2.21, 31.21) were the major predictors of death. The present findings indicate that scrub typhus may be considered a cause of CAP, ARDS, AUFI or a febrile illness with multisystem involvement, in Uttarakhand and Uttar Pradesh, especially from July to November. Empiric therapy of CAP may include doxycycline or azithromycin to ensure coverage of underlying unsuspected scrub typhus.

  15. Scrub typhus in Uttarakhand & adjoining Uttar Pradesh: Seasonality, clinical presentations & predictors of mortality

    Directory of Open Access Journals (Sweden)

    Anurag Bhargava

    2016-01-01

    Full Text Available Background & objectives: Scrub typhus is a re-emerging mite-borne rickettsiosis, which continues to be underdiagnosed, with lethal consequences. The present study was conducted to determine the seasonality, clinical presentation and predictors of mortality in patients with scrub typhus at a tertiary care teaching hospital in northern India. Methods: Scrub typhus was suspected in patients attending the hospital as per the standard case definition and serological evidence was obtained by performing an IgM ELISA. Results: A total of 284 patients with scrub typhus from urban and rural areas were seen, predominantly from July to November. The most common clinical presentation was a bilateral community-acquired pneumonia (CAP, which resembled pneumonia due to atypical pathogens and often progressed to acute respiratory distress syndrome (ARDS. An acute undifferentiated febrile illness (AUFI or a febrile illness associated with altered sensorium, aseptic meningitis, shock, abdominal pain, gastrointestinal bleeding or jaundice was also seen. Eschars were seen in 17 per cent of patients, and thrombocytopenia, transaminitis and azotaemia were frequent. There were 24 deaths (8.5% caused predominantly by ARDS and multi-organ dysfunction. The mortality in patients with ARDS was high (37%. ARDS [odds ratio (OR=38.29, 95% confidence interval (CI: 9.93, 147.71] and acute kidney injury (OR=8.30, 95% CI: 2.21, 31.21 were the major predictors of death. Interpretation & conclusions: The present findings indicate that scrub typhus may be considered a cause of CAP, ARDS, AUFI or a febrile illness with multisystem involvement, in Uttarakhand and Uttar Pradesh, especially from July to November. Empiric therapy of CAP may include doxycycline or azithromycin to ensure coverage of underlying unsuspected scrub typhus.

  16. Global Warming on Triton

    Science.gov (United States)

    Elliot, J. L.; Hammel, H. B.; Wasserman, L. H.; Franz, O. G.; McDonald, S. W.; Person, M. J.; Olkin, C. B.; Dunham, E. J.; Spencer, J. R.; Stansberry, J. A.; hide

    1998-01-01

    Triton, Neptune's largest moon, has been predicted to undergo significant seasonal changes that would reveal themselves as changes in its mean frost temperature. But whether this temperature should at the present time be increasing, decreasing or constant depends on a number of parameters (such as the thermal properties of the surface, and frost migration patterns) that are unknown. Here we report observations of a recent stellar occultation by Triton which, when combined with earlier results, show that Triton has undergone a period of global warming since 1989. Our most conservative estimates of the rate of temperature and surface-pressure increase during this period imply that the atmosphere is doubling in bulk every 10 years, significantly faster than predicted by any published frost model for Triton. Our result suggests that permanent polar caps on Triton play a c dominant role in regulating seasonal atmospheric changes. Similar processes should also be active on Pluto.

  17. Disentangling Seasonality and Mean Annual Precipitation in the Indo-Pacific Warm Pool: Insights from Coupled Plant Wax C and H Isotope Measurements

    Science.gov (United States)

    Galy, V.; Oppo, D.; Dubois, N.; Arbuszewski, J. A.; Mohtadi, M.; Schefuss, E.; Rosenthal, Y.; Linsley, B. K.

    2016-12-01

    There is ample evidence suggesting that rainfall distribution across the Indo-Pacific Warm Pool (IPWP) - a key component of the global climate system - has substantially varied over the last deglaciation. Yet, the precise nature of these hydroclimate changes remains to be elucidated. In particular, the relative importance of variations in precipitation seasonality versus annual precipitation amount is essentially unknown. Here we use a set of surface sediments from the IPWP covering a wide range of modern hydroclimate conditions to evaluate how plant wax stable isotope composition records rainfall distribution in the area. We focus on long chain fatty acids, which are exclusively produced by vascular plants living on nearby land and delivered to the ocean by rivers. We relate the C (δ13C) and H (δD) isotope composition of long chain fatty acids preserved in surface sediments to modern precipitation distribution and stable isotope composition in their respective source area. We show that: 1) δ13C values reflect vegetation distribution (in particular the relative abundance of C3 and C4 plants) and are primarily recording precipitation seasonality (Dubois et al., 2014) and, 2) once corrected for plant fractionation effects, δD values reflect the amount-weighted average stable isotope composition of precipitation and are primarily recording annual precipitation amounts. We propose that combining the C and H isotope composition of long chain fatty acids thus allows independent reconstructions of precipitation seasonality and annual amounts in the IPWP. The practical implications for reconstructing past hydroclimate in the IPWP will be discussed.

  18. Phytoplankton response to winter warming modified by large-bodied zooplankton: an experimental microcosm study

    Directory of Open Access Journals (Sweden)

    Hu He

    2015-03-01

    Full Text Available While several field investigations have demonstrated significant effects of cool season (winter or spring warming on phytoplankton development, the role played by large-bodied zooplankton grazers for the responses of phytoplankton to winter warming is ambiguous. We conducted an outdoor experiment to compare the effect of winter warming (heating by 3°C in combination with presence and absence of Daphnia grazing (D. similis on phytoplankton standing crops and community structure under eutrophic conditions. When Daphnia were absent, warming was associated with significant increases in phytoplankton biomass and cyanobacterial dominance. In contrast, when Daphnia were present, warming effects on phytoplankton dynamics were offset by warming-enhanced grazing, resulting in no significant change in biomass or taxonomic dominance. These results emphasize that large-bodied zooplankton like Daphnia spp. may play an important role in modulating the interactions between climate warming and phytoplankton dynamics in nutrient rich lake ecosystems.

  19. Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection

    Science.gov (United States)

    Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

    2016-01-01

    Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection. PMID:26838053

  20. Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection.

    Science.gov (United States)

    Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

    2016-02-03

    Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection.

  1. How does the dengue vector mosquito Aedes albopictus respond to global warming?

    OpenAIRE

    Jia, Pengfei; Chen, Xiang; Chen, Jin; Lu, Liang; Liu, Qiyong; Tan, Xiaoyue

    2017-01-01

    Background Global warming has a marked influence on the life cycle of epidemic vectors as well as their interactions with human beings. The Aedes albopictus mosquito as the vector of dengue fever surged exponentially in the last decade, raising ecological and epistemological concerns of how climate change altered its growth rate and population dynamics. As the global warming pattern is considerably uneven across four seasons, with a confirmed stronger effect in winter, an emerging need arises...

  2. Temperature extremes and infant mortality in Bangladesh: Hotter months, lower mortality.

    Science.gov (United States)

    Babalola, Olufemi; Razzaque, Abdur; Bishai, David

    2018-01-01

    Our study aims to obtain estimates of the size effects of temperature extremes on infant mortality in Bangladesh using monthly time series data. Data on temperature, child and infant mortality were obtained for Matlab district of rural Bangladesh for January 1982 to December 2008 encompassing 49,426 infant deaths. To investigate the relationship between mortality and temperature, we adopted a regression with Autoregressive Integrated Moving Average (ARIMA) errors model of seasonally adjusted temperature and mortality data. The relationship between monthly mean and maximum temperature on infant mortality was tested at 0 and 1 month lags respectively. Furthermore, our analysis was stratified to determine if the results differed by gender (boys versus girls) and by age (neonates (≤ 30 days) versus post neonates (>30days and Bangladesh. Each degree Celsius increase in mean monthly temperature reduced monthly mortality by 3.672 (SE 1.544, pBangladesh. This may reflect a more heightened sensitivity of infants to hypothermia than hyperthermia in this environment.

  3. Daily mortality and air pollutants: findings from Köln, Germany.

    Science.gov (United States)

    Spix, C; Wichmann, H E

    1996-04-01

    For the APHEA study, the short term effects of air pollutants on human health were investigated in a comparable way in various European cities. Daily mortality was used as one of the health effects indicators. This report aims to demonstrate the steps in epidemiological model building in this type of time series analysis aimed at detecting short term effects under a poisson distribution assumption and shows the tools for decision making. In addition, it assesses the impact of these steps on the pollution effect estimates. Köln, Germany, is a city of one million inhabitants. It is densely populated with a warm, humid, unfavourable climate and a high traffic density. In previous studies, smog episodes were found to increase mortality and higher sulphur dioxide (SO2) levels were connected with increases in the number of episodes of croup. Daily total mortality was obtained for 1975-85. SO2, total suspended particulates, and nitrogen dioxide (NO2) data were available from two to five stations for the city area, and size fractionated PM7 data from a neighbouring city. The main tools were time series plots of the raw data, predicted and residual data, the partial autocorrelation function and periodogram of the residuals, cross correlations of prefiltered series, plots of categorised influences, chi 2 statistics of influences and sensitivity analyses taking overdispersion and autocorrelation into account. With regard to model building, it is concluded that seasonal and epidemic correction are the most important steps. The actual model chosen depends very much on the properties of the data set. For the pollution effect estimates, trend, season, and epidemic corrections are important to avoid overestimation of the effect, while an appropriate short term meterology influence correction model may actually prevent underestimation. When the model leaves very little over-dispersion and autocorrelation in the residuals, which indicates a good fit, correction for them has

  4. On tropical cyclone frequency and the warm pool area

    Directory of Open Access Journals (Sweden)

    R. E. Benestad

    2009-04-01

    Full Text Available The proposition that the rate of tropical cyclogenesis increases with the size of the "warm pool" is tested by comparing the seasonal variation of the warm pool area with the seasonality of the number of tropical cyclones. An analysis based on empirical data from the Northern Hemisphere is presented, where the warm pool associated with tropical cyclone activity is defined as the area, A, enclosed by the 26.5°C SST isotherm. Similar analysis was applied to the temperature weighted area AT with similar results.

    An intriguing non-linear relationship of high statistical significance was found between the temperature weighted area in the North Atlantic and the North-West Pacific on the one hand and the number of cyclones, N, in the same ocean basin on the other, but this pattern was not found over the North Indian Ocean. A simple statistical model was developed, based on the historical relationship between N and A. The simple model was then validated against independent inter-annual variations in the seasonal cyclone counts in the North Atlantic, but the correlation was not statistically significant in the North-West Pacific. No correlation, however, was found between N and A in the North Indian Ocean.

    A non-linear relationship between the cyclone number and temperature weighted area may in some ocean basins explain both why there has not been any linear trend in the number of cyclones over time as well as the recent upturn in the number of Atlantic hurricanes. The results also suggest that the notion of the number of tropical cyclones being insensitive to the area A is a misconception.

  5. The Indo-Pacific Warm Pool: critical to world oceanography and world climate

    Science.gov (United States)

    De Deckker, Patrick

    2016-12-01

    The Indo-Pacific Warm Pool holds a unique place on the globe. It is a large area [>30 × 106 km2] that is characterised by permanent surface temperature >28 °C and is therefore called the `heat engine' of the globe. High convective clouds which can reach altitudes up to 15 km generate much latent heat in the process of convection and this area is therefore called the `steam engine' of the world. Seasonal and contrasting monsoonal activity over the region is the cause for a broad seasonal change of surface salinities, and since the area lies along the path of the Great Ocean Conveyor Belt, it is coined the `dilution' basin due to the high incidence of tropical rain and, away from the equator, tropical cyclones contribute to a significant drop in sea water salinity. Discussion about what may happen in the future of the Warm Pool under global warming is presented together with a description of the Warm Pool during the past, such as the Last Glacial Maximum when sea levels had dropped by ~125 m. A call for urgent monitoring of the IPWP area is justified on the grounds of the significance of this area for global oceanographic and climatological processes, but also because of the concerned threats to human population living there.

  6. Submesoscale processes promote seasonal restratification in the Subantarctic Ocean

    CSIR Research Space (South Africa)

    Du Plessis, M

    2017-04-01

    Full Text Available Traditionally, the mechanism driving the seasonal restratification of the Southern Ocean mixed layer (ML) is thought to be the onset of springtime warming. Recent developments in numerical modeling and North Atlantic observations have shown...

  7. Focus: Assessing the regional impacts of global warming

    International Nuclear Information System (INIS)

    Woo, Mingko

    1992-01-01

    Five studies are presented which assess the impacts of global warming on physical, economic, and social systems in Canada. A study on the use of climatic change scenarios to estimate ecoclimatic impacts was carried out. These scenarios may include synthetic scenarios produced from historical data, global climate model (GCM) simulations, and hybrid scenarios. The advantages and drawbacks of various scenarios are discussed along with the criteria for selecting impact assessment models. An examination of water resources in the Great Lakes and the Saskatchewan River subbasin uses case studies of two areas that have experienced wide hydrological variations due to climatic variability in order to determine the impacts of global warming scenarios on net basin supply. Problems of developing regional models are discussed and results of projected changes in net basin supply are presented for GCM-based simulations and hypothetical warming scenarios. A study of the impacts of climate warming on transportation and the regional economy in northern Canada uses stochastic models to provide examples of how Mackenzie River barge traffic will be affected. The economic impacts of the resultant lengthened shipping season are outlined under three scenarios. The implications of climatic change on Ontario agriculture are assessed according to GCM scenarios. Results are presented for crop yields and production as well as land resource suitability. Finally, sociocultural implications of global warming on the Arctic and the Inuit are summarized, with reference to a past warming episode occurring around the year 1000. 45 refs., 4 figs., 3 tabs

  8. Global warming and allergy in Asia Minor.

    Science.gov (United States)

    Bajin, Munir Demir; Cingi, Cemal; Oghan, Fatih; Gurbuz, Melek Kezban

    2013-01-01

    The earth is warming, and it is warming quickly. Epidemiological studies have demonstrated that global warming is correlated with the frequency of pollen-induced respiratory allergy and allergic diseases. There is a body of evidence suggesting that the prevalence of allergic diseases induced by pollens is increasing in developed countries, a trend that is also evident in the Mediterranean area. Because of its mild winters and sunny days with dry summers, the Mediterranean area is different from the areas of central and northern Europe. Classical examples of allergenic pollen-producing plants of the Mediterranean climate include Parietaria, Olea and Cupressaceae. Asia Minor is a Mediterranean region that connects Asia and Europe, and it includes considerable coastal areas. Gramineae pollens are the major cause of seasonal allergic rhinitis in Asia Minor, affecting 1.3-6.4 % of the population, in accordance with other European regions. This article emphasizes the importance of global climate change and anticipated increases in the prevalence and severity of allergic disease in Asia Minor, mediated through worsening air pollution and altered local and regional pollen production, from an otolaryngologic perspective.

  9. Performance Measures of Warm Asphalt Mixtures for Safe and Reliable Freight Transportation

    Science.gov (United States)

    2009-04-01

    Warm mix asphalt (WMA) is an emerging technology that can allow asphalt to flow at a lower temperature for mixing, placing and compaction. The advantages of WMA include reduced fuel consumption, less carbon dioxide emission, longer paving season, lon...

  10. Coral Reefs: Beyond Mortality?

    Directory of Open Access Journals (Sweden)

    Charles Sheppard

    2000-01-01

    Full Text Available The scale of the collapse of coral reef communities in 1998 following a warming episode (Wilkinson, 2000 was unprecedented, and took many people by surprise. The Indian Ocean was the worst affected with a coral mortality over 75% in many areas such as the Chagos Archipelago (Sheppard, 1999, Seychelles (Spencer et al., 2000 and Maldives (McClanahan, 2000. Several other locations were affected at least as much, with mortality reaching 100% (to the nearest whole number; this is being compiled by various authors (e.g., CORDIO, in press. For example, in the Arabian Gulf, coral mortality is almost total across many large areas of shallow water (Sheppard, unpublished; D. George and D. John, personal communication. The mortality is patchy of course, depending on currents, location inside or outside lagoons, etc., but it is now possible to swim for over 200 m and see not one remaining living coral or soft coral on some previously rich reefs.

  11. Global Warming Induced Changes in Rainfall Characteristics in IPCC AR5 Models

    Science.gov (United States)

    Lau, William K. M.; Wu, Jenny, H.-T.; Kim, Kyu-Myong

    2012-01-01

    Changes in rainfall characteristic induced by global warming are examined from outputs of IPCC AR5 models. Different scenarios of climate warming including a high emissions scenario (RCP 8.5), a medium mitigation scenario (RCP 4.5), and 1% per year CO2 increase are compared to 20th century simulations (historical). Results show that even though the spatial distribution of monthly rainfall anomalies vary greatly among models, the ensemble mean from a sizable sample (about 10) of AR5 models show a robust signal attributable to GHG warming featuring a shift in the global rainfall probability distribution function (PDF) with significant increase (>100%) in very heavy rain, reduction (10-20% ) in moderate rain and increase in light to very light rains. Changes in extreme rainfall as a function of seasons and latitudes are also examined, and are similar to the non-seasonal stratified data, but with more specific spatial dependence. These results are consistent from TRMM and GPCP rainfall observations suggesting that extreme rainfall events are occurring more frequently with wet areas getting wetter and dry-area-getting drier in a GHG induced warmer climate.

  12. The effect of seasonality on burn incidence, severity and outcome in Central Malawi.

    Science.gov (United States)

    Tyson, Anna F; Gallaher, Jared; Mjuweni, Stephen; Cairns, Bruce A; Charles, Anthony G

    2017-08-01

    In much of the world, burns are more common in cold months. However, few studies have described the seasonality of burns in sub-Saharan Africa. This study examines the effect of seasonality on the incidence and outcome of burns in central Malawi. A retrospective analysis was performed at Kamuzu Central Hospital and included all patients admitted from May 2011 to August 2014. Demographic data, burn mechanism, total body surface area (%TBSA), and mortality were analyzed. Seasons were categorized as Rainy (December-February), Lush (March-May), Cold (June-August) and Hot (September-November). A negative binomial regression was used to assess the effect of seasonality on burn incidence. This was performed using both the raw and deseasonalized data in order to evaluate for trends not attributable to random fluctuation. A total of 905 patients were included. Flame (38%) and Scald (59%) burns were the most common mechanism. More burns occurred during the cold season (41% vs 19-20% in the other seasons). Overall mortality was 19%. Only the cold season had a statistically significant increase in burn . The incidence rate ratios (IRR) for the hot, lush, and cold seasons were 0.94 (CI 0.6-1.32), 1.02 (CI 0.72-1.45) and 1.6 (CI 1.17-2.19), respectively, when compared to the rainy season. Burn severity and mortality did not differ between seasons. The results of this study demonstrate the year-round phenomenon of burns treated at our institution, and highlights the slight predominance of burns during the cold season. These data can be used to guide prevention strategies, with special attention to the implications of the increased burn incidence during the cold season. Though burn severity and mortality remain relatively unchanged between seasons, recognizing the seasonal variability in incidence of burns is critical for resource allocation in this low-income setting. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  13. The age distribution of mortality due to influenza: pandemic and peri-pandemic

    Science.gov (United States)

    2012-01-01

    Background Pandemic influenza is said to 'shift mortality' to younger age groups; but also to spare a subpopulation of the elderly population. Does one of these effects dominate? Might this have important ramifications? Methods We estimated age-specific excess mortality rates for all-years for which data were available in the 20th century for Australia, Canada, France, Japan, the UK, and the USA for people older than 44 years of age. We modeled variation with age, and standardized estimates to allow direct comparison across age groups and countries. Attack rate data for four pandemics were assembled. Results For nearly all seasons, an exponential model characterized mortality data extremely well. For seasons of emergence and a variable number of seasons following, however, a subpopulation above a threshold age invariably enjoyed reduced mortality. 'Immune escape', a stepwise increase in mortality among the oldest elderly, was observed a number of seasons after both the A(H2N2) and A(H3N2) pandemics. The number of seasons from emergence to escape varied by country. For the latter pandemic, mortality rates in four countries increased for younger age groups but only in the season following that of emergence. Adaptation to both emergent viruses was apparent as a progressive decrease in mortality rates, which, with two exceptions, was seen only in younger age groups. Pandemic attack rate variation with age was estimated to be similar across four pandemics with very different mortality impact. Conclusions In all influenza pandemics of the 20th century, emergent viruses resembled those that had circulated previously within the lifespan of then-living people. Such individuals were relatively immune to the emergent strain, but this immunity waned with mutation of the emergent virus. An immune subpopulation complicates and may invalidate vaccine trials. Pandemic influenza does not 'shift' mortality to younger age groups; rather, the mortality level is reset by the virulence

  14. Early onset of significant local warming in low latitude countries

    International Nuclear Information System (INIS)

    Mahlstein, I; Knutti, R; Solomon, S; Portmann, R W

    2011-01-01

    The Earth is warming on average, and most of the global warming of the past half-century can very likely be attributed to human influence. But the climate in particular locations is much more variable, raising the question of where and when local changes could become perceptible enough to be obvious to people in the form of local warming that exceeds interannual variability; indeed only a few studies have addressed the significance of local signals relative to variability. It is well known that the largest total warming is expected to occur in high latitudes, but high latitudes are also subject to the largest variability, delaying the emergence of significant changes there. Here we show that due to the small temperature variability from one year to another, the earliest emergence of significant warming occurs in the summer season in low latitude countries (∼25 deg. S-25 deg. N). We also show that a local warming signal that exceeds past variability is emerging at present, or will likely emerge in the next two decades, in many tropical countries. Further, for most countries worldwide, a mean global warming of 1 deg. C is sufficient for a significant temperature change, which is less than the total warming projected for any economically plausible emission scenario. The most strongly affected countries emit small amounts of CO 2 per capita and have therefore contributed little to the changes in climate that they are beginning to experience.

  15. A comparative simple method for human bioclimatic conditions applied to seasonally hot/warm cities of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Tejeda Martinez, A. [Universidad Veracruzana, Xalapa, Veracruz (Mexico); Garcia Cueto, O.R. [Universidad Autonoma de Baja California, Mexicali, B.C. (Mexico)

    2002-01-01

    The climate of a region is an environmental resource with important implications for things such as thermal comfort, health and productivity of the population. In this work, the bioclimatic comfort was evaluated for seven seasonally warm/hot cities of Mexico by means of the following current indexes: Discomfort Index, Enthalpy Index and Heat Strain Index. Also, the periods during which it is necessary to use air conditioning in the studied cities were calculated from estimated global radiation and hourly data of temperature and relative humidity which made it possible to establish them with high precision. Finally, the useful of the Heat Strain Index is shown. It is a simple index needing available meteorological data to compare bioclimatic conditions of similar sites. [Spanish] El clima regional tiene implicaciones en el confort, la salud y la productividad de la poblacion. En este articulo se presentan las evaluaciones bioclimaticas comparativas de siete ciudades calidas de Mexico. Se aplicaron los indices bioclimaticos de disconfort, entalpia y esfuerzo frente al calor. Se calcularon los periodos para los cuales es necesario el uso de aire acondicionado, a partir de estimaciones de radiacion solar global y de temperatura y humedad horarias medias mensuales. Finalmente se muestra la utilidad y calidad del Indice de esfuerzo frente al calor, el cual requiere solo de datos climatologicos comunes para poder comparar condiciones bioclimaticas de sitios similares.

  16. Impact of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis

    Directory of Open Access Journals (Sweden)

    Frédéric eGazeau

    2014-11-01

    Full Text Available In order to assess the effects of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis, specimens were reared in aquarium tanks and exposed to elevated conditions of temperature (+3 °C and acidity (-0.3 pH units for a period of 10 months. The whole system comprised a factorial experimental design with 4 treatments (3 aquaria per treatment: control, lowered pH, elevated temperature and lowered pH/elevated temperature. Mortality was estimated on a weekly basis and every 2 months, various biometrical parameters and physiological processes were measured: somatic and shell growth, metabolic rates and body fluid acid-base parameters. Mussels were highly sensitive to warming, with 100 % mortality observed under elevated temperature at the end of our experiment in October. Mortality rates increased drastically in summer, when water temperature exceeded 25 °C. In contrast, our results suggest that survival of this species will not be affected by a pH decrease of ~0.3 in the Mediterranean Sea. Somatic and shell growth did not appear very sensitive to ocean acidification and warming during most of the experiment, but were reduced, after summer, in the lowered pH treatment. This was consistent with measured shell net dissolution and observed loss of periostracum, as well as uncompensated extracellular acidosis in the lowered pH treatment indicating a progressive insufficiency in acid-base regulation capacity. However, based on the present dataset, we cannot elucidate if these decreases in growth and regulation capacities after summer are a consequence of lower pH levels during that period or a consequence of a combined effect of acidification and warming. To summarize, while ocean acidification will potentially contribute to lower growth rates, especially in summer when mussels are exposed to sub-optimal conditions, ocean warming will likely pose more serious threats to Mediterranean mussels in this region in the coming

  17. Effects of diurnal temperature range on mortality in Hefei city, China

    Science.gov (United States)

    Tang, Jing; Xiao, Chang-chun; Li, Yu-rong; Zhang, Jun-qing; Zhai, Hao-yuan; Geng, Xi-ya; Ding, Rui; Zhai, Jin-xia

    2018-05-01

    Although several studies indicated an association between diurnal temperature range (DTR) and mortality, the results about modifiers are inconsistent, and few studies were conducted in developing inland country. This study aims to evaluate the effects of DTR on cause-specific mortality and whether season, gender, or age might modify any association in Hefei city, China, during 2007-2016. Quasi-Poisson generalized linear regression models combined with a distributed lag non-linear model (DLNM) were applied to evaluate the relationships between DTR and non-accidental, cardiovascular, and respiratory mortality. We observed a J-shaped relationship between DTR and cause-specific mortality. With a DTR of 8.3 °C as the reference, the cumulative effects of extremely high DTR were significantly higher for all types of mortality than effects of lower or moderate DTR in full year. When stratified by season, extremely high DTR in spring had a greater impact on all cause-specific mortality than other three seasons. Male and the elderly (≥ 65 years) were consistently more susceptible to extremely high DTR effect than female and the youth (groups from extremely high DTR especially in the spring.

  18. Effects of warming on N2O fluxes in a boreal peatland of Permafrost region, Northeast China.

    Science.gov (United States)

    Cui, Qian; Song, Changchun; Wang, Xianwei; Shi, Fuxi; Yu, Xueyang; Tan, Wenwen

    2018-03-01

    Climate warming is expected to increasingly influence boreal peatlands and alter their greenhouse gases emissions. However, the effects of warming on N 2 O fluxes and the N 2 O budgets were ignored in boreal peatlands. Therefore, in a boreal peatland of permafrost zone in Northeast China, a simulated warming experiment was conducted to investigate the effects of warming on N 2 O fluxes in Betula. Fruticosa community (B. Fruticosa) and Ledum. palustre community (L. palustre) during the growing seasons from 2013 to 2015. Results showed that warming treatment increased air temperature at 1.5m aboveground and soil temperature at 5cm depth by 0.6°C and 2°C, respectively. The average seasonal N 2 O fluxes ranged from 6.62 to 9.34μgm -2 h -1 in the warming plot and ranged from 0.41 to 4.55μgm -2 h -1 in the control plots. Warming treatment increased N 2 O fluxes by 147% and transformed the boreal peatlands from a N 2 O sink to a source. The primary driving factors for N 2 O fluxes were soil temperature and active layer depth, whereas soil moisture showed a weak correlation with N 2 O fluxes. The results indicated that warming promoted N 2 O fluxes by increasing soil temperature and active layer depth in a boreal peatland of permafrost zone in Northeast China. Moreover, elevated N 2 O fluxes persisted in this region will potentially drive a noncarbon feedback to ongoing climate change. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Decline of coral reefs during late Paleocene to early Eocene global warming

    OpenAIRE

    Scheibner , C.; Speijer , R. P.

    2007-01-01

    International audience; Since the 1980s the frequency of warming events has intensified and simultaneously widespread coral bleaching, and enhanced coral mortality have been observed. Yet, it remains unpredictable how tropical coral reef communities will react to prolonged adverse conditions. Possibly, coral reef systems are sufficiently robust to withstand continued environmental pressures. But if coral mortality increases, what will platform communities of the future look like? The co-evolu...

  20. Fire Safety During the Holiday Season | Poster

    Science.gov (United States)

    Winter is here, and that means holiday decorations, a warm hearth, and (hopefully) plenty of homecooked meals. Unfortunately, winter also brings numerous fire hazards both at work and around the house. This year, as you shop, decorate, and celebrate, keep these safety tips in mind to ensure a safe and enjoyable holiday season.

  1. A warm-season comparison of WRF coupled to the CLM4.0, Noah-MP, and Bucket hydrology land surface schemes over the central USA

    Science.gov (United States)

    Van Den Broeke, Matthew S.; Kalin, Andrew; Alavez, Jose Abraham Torres; Oglesby, Robert; Hu, Qi

    2017-11-01

    In climate modeling studies, there is a need to choose a suitable land surface model (LSM) while adhering to available resources. In this study, the viability of three LSM options (Community Land Model version 4.0 [CLM4.0], Noah-MP, and the five-layer thermal diffusion [Bucket] scheme) in the Weather Research and Forecasting model version 3.6 (WRF3.6) was examined for the warm season in a domain centered on the central USA. Model output was compared to Parameter-elevation Relationships on Independent Slopes Model (PRISM) data, a gridded observational dataset including mean monthly temperature and total monthly precipitation. Model output temperature, precipitation, latent heat (LH) flux, sensible heat (SH) flux, and soil water content (SWC) were compared to observations from sites in the Central and Southern Great Plains region. An overall warm bias was found in CLM4.0 and Noah-MP, with a cool bias of larger magnitude in the Bucket model. These three LSMs produced similar patterns of wet and dry biases. Model output of SWC and LH/SH fluxes were compared to observations, and did not show a consistent bias. Both sophisticated LSMs appear to be viable options for simulating the effects of land use change in the central USA.

  2. Aquifer Thermal Energy Storage for Seasonal Thermal Energy Balance

    Science.gov (United States)

    Rostampour, Vahab; Bloemendal, Martin; Keviczky, Tamas

    2017-04-01

    Aquifer Thermal Energy Storage (ATES) systems allow storing large quantities of thermal energy in subsurface aquifers enabling significant energy savings and greenhouse gas reductions. This is achieved by injection and extraction of water into and from saturated underground aquifers, simultaneously. An ATES system consists of two wells and operates in a seasonal mode. One well is used for the storage of cold water, the other one for the storage of heat. In warm seasons, cold water is extracted from the cold well to provide cooling to a building. The temperature of the extracted cold water increases as it passes through the building climate control systems and then gets simultaneously, injected back into the warm well. This procedure is reversed during cold seasons where the flow direction is reversed such that the warmer water is extracted from the warm well to provide heating to a building. From the perspective of building climate comfort systems, an ATES system is considered as a seasonal storage system that can be a heat source or sink, or as a storage for thermal energy. This leads to an interesting and challenging optimal control problem of the building climate comfort system that can be used to develop a seasonal-based energy management strategy. In [1] we develop a control-oriented model to predict thermal energy balance in a building climate control system integrated with ATES. Such a model however cannot cope with off-nominal but realistic situations such as when the wells are completely depleted, or the start-up phase of newly installed wells, etc., leading to direct usage of aquifer ambient temperature. Building upon our previous work in [1], we here extend the mathematical model for ATES system to handle the above mentioned more realistic situations. Using our improved models, one can more precisely predict system behavior and apply optimal control strategies to manage the building climate comfort along with energy savings and greenhouse gas reductions

  3. Direct and indirect mortality in Florida during the 2004 hurricane season

    Science.gov (United States)

    McKinney, Nathan; Houser, Chris; Meyer-Arendt, Klaus

    2011-07-01

    Previous studies have shown that natural disasters, and hurricanes in particular, have led to more deaths than those usually documented in short post-storm surveys. Such indirect deaths, thought to be related to dietary, stress or pre-existing medical conditions, can exceed the number of direct deaths and may persist for weeks or even months beyond the event itself. In the present study, cumulative sum of deviations plots are used to quantify the number of direct and indirect deaths resulting from Hurricanes Charley, Frances, Ivan and Jeanne that made landfall in Florida in 2004. Results suggest that there was an elevated mortality for up to 2 months following each storm, resulting in a total of 624 direct and indirect deaths attributable to the storm. Trauma-related deaths that can be associated directly with the storm account for only ˜4% of the total storm-related mortality, while indirect mortality accounts for most storm-related deaths. Specifically, a large percentage of the elevated mortality was associated with heart (34%) and cancer-related deaths (19%), while diabetes (5%) and accident-related deaths (9%) account for a smaller but still significant percentage of the elevated mortality. The results further suggest that the elevated mortality was the result of additional deaths that would not have otherwise occurred within that 5 month period, and not simply a clustering of deaths that were inevitable between 1 August and 31 December 2004. The elevated mortality identified in this study is significantly greater than the official count of 31 direct and 113 indirect deaths resulting from the four hurricanes combined. This suggests a need for improved mortality counts and surveillance in order to better evaluate and identify effective prevention policies, and to identify preventable deaths.

  4. Mortality, diarrhea and respiratory disease in Danish dairy heifer calves

    DEFF Research Database (Denmark)

    Reiten, M.; Rousing, T.; Thomsen, P. T.

    2018-01-01

    system (conventional/organic), season (summer/winter) and calf mortality risk, diarrhea, signs of respiratory disease and ocular discharge, respectively, for dairy heifer calves aged 0–180 days. Sixty Danish dairy herds, 30 conventional and 30 organic, were visited once during summer and once during......Diarrhea and respiratory disease are major health problems for dairy calves, often causing calf mortality. Previous studies have found calf mortality to be higher in organic dairy herds compared to conventional herds. The aim of this study was to investigate the association between production...... variables and in certain age groups, dependent on production system and season....

  5. Temperature effects on seaweed-sustaining top-down control vary with season.

    Science.gov (United States)

    Werner, Franziska J; Graiff, Angelika; Matthiessen, Birte

    2016-03-01

    Rising seawater temperature and CO2 concentrations (ocean acidification) represent two of the most influential factors impacting marine ecosystems in the face of global climate change. In ecological climate change research, full-factorial experiments performed across seasons in multispecies, cross-trophic-level settings are essential as they permit a more realistic estimation of direct and indirect effects as well as the relative importance of the effects of both major environmental stressors on ecosystems. In benthic mesocosm experiments, we tested the responses of coastal Baltic Sea Fucus vesiculosus communities to elevated seawater temperature and CO2 concentrations across four seasons of one year. While increasing [CO2] levels had only minor effects, warming had strong and persistent effects on grazers, and the resulting effects on the Fucus community were found to be season dependent. In late summer, a temperature-driven collapse of grazers caused a cascading effect from the consumers to the foundation species, resulting in overgrowth of Fucus thalli by epiphytes. In fall/winter (outside the growing season of epiphytes), intensified grazing under warming resulted in a significant reduction in Fucus biomass. Thus, we were able to confirm the prediction that future increases in water temperatures will influence marine food-web processes by altering top-down control, but we were also able to show that specific consequences for food-web structure depend on the season. Since F. vesiculosus is the dominant habitat-forming brown algal system in the Baltic Sea, its potential decline under global warming implies a loss of key functions and services such as provision of nutrient storage, substrate, food, shelter, and nursery grounds for a diverse community of marine invertebrates and fish in Baltic Sea coastal waters.

  6. Summer heat and mortality in New York City: how hot is too hot?

    Science.gov (United States)

    Metzger, Kristina B; Ito, Kazuhiko; Matte, Thomas D

    2010-01-01

    To assess the public health risk of heat waves and to set criteria for alerts for -excessive heat, various meteorologic metrics and models are used in different jurisdictions, generally without systematic comparisons of alternatives. We report such an analysis for New York City that compared maximum heat index with alternative metrics in models to predict daily variation in warm-season natural-cause mortality from 1997 through 2006. We used Poisson time-series generalized linear models and generalized additive models to estimate weather-mortality relationships using various metrics, lag and averaging times, and functional forms and compared model fit. A model that included cubic functions of maximum heat index on the same and each of the previous 3 days provided the best fit, better than models using maximum, minimum, or average temperature, or spatial synoptic classification (SSC) of weather type. We found that goodness of fit and maximum heat index-mortality functions were similar using parametric and nonparametric models. Same-day maximum heat index was linearly related to mortality risk across its range. The slopes at lags of 1, 2, and 3 days were flat across moderate values but increased sharply between maximum heat index of 95 degrees F and 100 degrees F (35-38 degrees C). SSC or other meteorologic variables added to the maximum heat index model moderately improved goodness of fit, with slightly attenuated maximum heat index-mortality functions. In New York City, maximum heat index performed similarly to alternative and more complex metrics in estimating mortality risk during hot weather. The linear relationship supports issuing heat alerts in New York City when the heat index is forecast to exceed approximately 95-100 degrees F. Periodic city-specific analyses using recent data are recommended to evaluate public health risks from extreme heat.

  7. Short-term effect of fine particulate air pollution on daily mortality: a case-crossover study in a tropical city, Kaohsiung, Taiwan.

    Science.gov (United States)

    Tsai, Shang-Shyue; Chen, Chih-Cheng; Yang, Chun-Yuh

    2014-01-01

    Many studies have examined the short-term effects of air pollution on frequency of daily mortality over the past two decades. However, information on the relationship between levels of fine particles (PM(2.5)) and daily mortality is relatively sparse due to limited availability of monitoring data. Further the results are inconsistent. This study was undertaken to determine whether there was an association between PM(2.5) levels and daily mortality rate in Kaohsiung, Taiwan, a large industrial city with a tropical climate. Daily mortality rate, air pollution parameters, and weather data for Kaohsiung were obtained for the period from 2006 through 2008. The relative risk of daily mortality occurrence was estimated using a time-stratified case-crossover approach, controlling for (1) weather variables, (2) day of the week, (3) seasonality, and (4) long-term time trends. For the single-pollutant model (without adjustment for other pollutants), no significant effects were found between PM(2.5) and frequency of daily mortality on warm days (≥25°C). On cool days, PM(2.5) showed significant correlation with increased risk of mortality rate for all causes and circulatory diseases in single-pollutant model. There was no indication of an association between PM(2.5) and deaths due to respiratory diseases. The relationship appeared to be stronger on cool days. This study provided evidence of associations between short-term exposure to PM(2.5) and elevated risk of death for all cause and circulatory diseases.

  8. [The innovation of warm disease theory in the Ming Dynasty before Wen yi lun On Pestilence].

    Science.gov (United States)

    Zhang, Zhi-bin

    2008-10-01

    Some doctors of the Ming dynasty raised subversive doubts against the traditional viewpoints of "exogenous cold disease is warm-heat" before the emergence of Wen yi lun (On Pestilence), holding that warm-heat disease "is contracted in different seasons instead of being transformed from cold to warm and/or heat". The conception of the separation of warm-heat disease and exogenous cold disease had changed from obscure to clear. As the idea became clear, the recognition on the new affection of warm, heat, summer-heat, pestilent pathogen was formed, and the idea that the pathogens of summer-heat and warm entered the human body through the mouth and nostrils was put forward. The six-channel syndrome differentiation of warm disease and the five sweat-resolving methods in pestilence raised by the doctors of this period are the aspects of the differential diagnosis of syndrome and treatment in warm diseases, and deserve to be paid attention to.

  9. The Effects of Coarse Particles on Daily Mortality: A Case-Crossover Study in a Subtropical City, Taipei, Taiwan

    Directory of Open Access Journals (Sweden)

    Meng-Hsuan Cheng

    2016-03-01

    Full Text Available Many studies have examined the effects of air pollution on daily mortality over the past two decades. However, information on the relationship between levels of coarse particles (PM2.5–10 and daily mortality is relatively sparse due to the limited availability of monitoring data. Furthermore, the results are inconsistent. In the current study, the association between coarse particle levels and daily mortality in Taipei, Taiwan’s largest city, which has a subtropical climate, was undertaken for the period 2006–2008 using a time-stratified case-crossover analysis. For the single pollutant model (without adjustment for other pollutants, PM2.5–10 showed statistically significant association with total mortality both on warm and cool days, with an interquartile range increase associated with a 11% (95% CI = 6%–17% and 4% (95% CI = 1%–7% rise in number of total deaths, respectively. In two-pollutant models, PM2.5–10 remained significant effects on total mortality after the inclusion of SO2 and O3 both on warm and cool days. We observed no significant associations between PM2.5–10 and daily mortality from respiratory diseases both on warm and cool days. For daily mortality from circulatory diseases, the effect of PM2.5–10 remained significant when SO2 or O3 was added in the regression model both on warm and cool days. Future studies of this type in cities with varying climates and cultures are needed.

  10. Coupled prediction of flood response and debris flow initiation during warm and cold season events in the Southern Appalachians, USA

    Science.gov (United States)

    Tao, J.; Barros, A. P.

    2013-07-01

    Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas warm season events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold season events. Instead, there is a relationship between large (cumulative) rainfall events independently of season, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. The first objective of this study is to investigate this hypothesis. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations, availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions, and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions necessary for the initiation of slope instability, and should therefore be considered explicitly in landslide hazard assessments. Moreover, the relationships between slope stability and interflow are

  11. Soil Temperature Manipulation to Study Global Warming Effects in Arable Land

    DEFF Research Database (Denmark)

    Patil, R H; Laegdsmand, M; Olesen, Jørgen E

    2013-01-01

    in a plough layer. Temperature sensors were placed at 0.05, 0.1 and 0.25 m depths in soil, and 0.1 m above the soil surface in all plots, which were connected to an automated data logger. Soil-warming setup was able to maintain a mean seasonal temperature difference of 5.0 ± 0.005℃ between heated and control......-ground vegetation response as this method heats only the soil. Therefore, using infrared heaters seems to represent natural climate warming (both air and soil) much more closely and may be used for future climate manipulation field studies....

  12. Soil temperature manipulation to study global warming effects in arable land

    DEFF Research Database (Denmark)

    Patil, Raveendra H.; Laegdsmand, Mette; Olesen, Jørgen Eivind

    2013-01-01

    in a plough layer. Temperature sensors were placed at 0.05, 0.1 and 0.25 m depths in soil, and 0.1 m above the soil surface in all plots, which were connected to an automated data logger. Soil-warming setup was able to maintain a mean seasonal temperature difference of 5.0 ± 0.005 oC between heated...... that of above-ground vegetation response as this method heats only the soil. Therefore, using infrared heaters seems to represent natural climate warming (both air and soil) much more closely and may be used for future climate manipulation field studies....

  13. FVS and global Warming: A prospectus for future development

    Science.gov (United States)

    Nicholas L. Crookston; Gerald E. Rehfeldt; Dennis E. Ferguson; Marcus Warwell

    2008-01-01

    Climate change-global warming and changes in precipitation-will cause changes in tree growth rates, mortality rates, the distribution of tree species, competition, and species interactions. An implicit assumption in FVS is that site quality will remain the same as it was during the time period observations used to calibrate the component models were made and that the...

  14. Seasonal and elevational contrasts in temperature trends in Central Chile between 1979 and 2015

    Science.gov (United States)

    Burger, F.; Brock, B.; Montecinos, A.

    2018-03-01

    We analyze trends in temperature from 18 temperature stations and one upper air sounding site at 30°-35° S in central Chile between 1979-2015, to explore geographical and season temperature trends and their controls, using regional ocean-atmosphere indices. Significant warming trends are widespread at inland stations, while trends are non-significant or negative at coastal sites, as found in previous studies. However, ubiquitous warming across the region in the past 8 years, suggests the recent period of coastal cooling has ended. Significant warming trends are largely restricted to austral spring, summer and autumn seasons, with very few significant positive or negative trends in winter identified. Autumn warming is notably strong in the Andes, which, together with significant warming in spring, could help to explain the negative mass balance of snow and glaciers in the region. A strong Pacific maritime influence on regional temperature trends is inferred through correlation with the Interdecadal Pacific Oscillation (IPO) index and coastal sea surface temperature, but the strength of this influence rapidly diminishes inland, and the majority of valley, and all Andes, sites are independent of the IPO index. Instead, valley and Andes sites, and mid-troposphere temperature in the coastal radiosonde profile, show correlation with the autumn Antarctic Oscillation which, in its current positive phase, promotes subsidence and warming at the latitude of central Chile.

  15. Is precipitation a predictor of mortality in Bangladesh? A multi-stratified analysis in a South Asian monsoon climate.

    Science.gov (United States)

    Burkart, Katrin; Kinney, Patrick

    2016-05-15

    While numerous studies have assessed the association between temperature and mortality in various locations, few have addressed the relationship between precipitation and mortality. Given the high amounts of rainfall in many tropical monsoon areas and the often seasonally pronounced differences, there might be a potentially strong impact on health outcomes and death. In this study, we investigated the association between precipitation and daily death counts in Bangladesh from 2003 to 2007 using regression models with a quasipoisson distribution adjusting for long-term time and seasonal trends, day of the month, age and perceived temperature. Effects were assessed for all ages, the elderly and by gender. During the dry season a sharp increase in death risk was found at very high precipitation amounts which are most likely to be cyclone-related. This cyclone effect was most pronounced for females at the immediate day with an increase of 18.7% (3.8-35.6%) in non-external cause mortality per mm precipitation above 5mm. At longer lags we found a negative association between precipitation and mortality indicating some kind of dry effect which was more pronounced for the elderly with a mortality increase of 4.4% (2.6-6.2%) per mm decrease in precipitation. During the rainy season, we observed a protective effect of rainfall which was strongest during periods of seasonally high equivalent temperatures with a decrease in mortality of 4.0% (2.3-5.6%) per mm increase in precipitation on the immediate day. The observed associations between precipitation and mortality differed by season, age and gender. Generally, a strong short-term increase in mortality was associated with cyclonic activity during the dry season, while ongoing low rainfall seemed to have an adverse impact at higher lags. During the rainy season, precipitation seemed to mitigate heat effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Differences on the effect of heat waves on mortality by sociodemographic and urban landscape characteristics.

    Science.gov (United States)

    Xu, Yihan; Dadvand, Payam; Barrera-Gómez, Jose; Sartini, Claudio; Marí-Dell'Olmo, Marc; Borrell, Carme; Medina-Ramón, Mercè; Sunyer, Jordi; Basagaña, Xavier

    2013-06-01

    Mortality increases during heat waves have been reported worldwide. The magnitude of these increases can vary within regions according to sociodemographic and urban landscape characteristics. The objectives of this study were to explore this variation and its determinants, and to identify the most heat-vulnerable areas by mapping heat vulnerability. We conducted a time-stratified case-crossover analysis using daily mortality in the Barcelona metropolitan area during the warm seasons of 1999-2006. Temperature data on the date of death were assigned to each individual, which were assigned to their census tract of residence. Eight census tract-level variables on socioeconomic or built environment characteristics were obtained from the census. Residence surrounding greenness was obtained from satellite data. The relative risk (RR) of mortality after three consecutive hot days (defined as those exceeding the 95th percentile of maximum temperature) was calculated via conditional logistic regression. Effect modification was examined by including interaction terms. Analyses were based on 52 806 deaths. The effect of three consecutive hot days was a 30% increase in all-cause mortality (RR=1.30, 95% CI 1.24 to 1.38). Heterogeneity of this effect was observed across census tracts. The effect of heat on mortality was higher in the census tracts with a large percentage of old buildings (RR=1.21, 95% CI 1.00 to 1.46), manual workers (RR=1.25, 95% CI 0.96 to 1.64) and residents perceiving little surrounding greenness (RR=1.29, 95% CI 1.01 to 1.65). After three consecutive hot days, mortality doubled in the most heat-vulnerable census tracts. Sociodemographic and urban landscape characteristics are associated to mortality risk during heat waves and are useful to build heat vulnerability maps.

  17. Water runoff vs modern climatic warming in mountainous cryolithic zone in North-East Russia

    Science.gov (United States)

    Glotov, V. E.; Glotova, L. P.

    2018-01-01

    The article presents the results of studying the effects of current climatic warming for both surface and subsurface water runoffs in North-East Russia, where the Main Watershed of the Earth separates it into the Arctic and Pacific continental slopes. The process of climatic warming is testified by continuous weather records during 80-100 years and longer periods. Over the Arctic slope and in the northern areas of the Pacific slope, climatic warming results in a decline in a total runoff of rivers whereas the ground-water recharge becomes greater in winter low-level conditions. In the southern Pacific slope and in the Sea of Okhotsk basin, the effect of climatic warming is an overall increase in total runoff including its subsurface constituents. We believe these peculiar characters of river runoff there to be related to the cryolithic zone environments. Over the Arctic slope and the northern Pacific slope, where cryolithic zone is continuous, the total runoff has its subsurface constituent as basically resulting from discharge of ground waters hosted in seasonally thawing rocks. Warmer climatic conditions favor growth of vegetation that needs more water for the processes of evapotranspiration and evaporation from rocky surfaces in summer seasons. In the Sea of Okhotsk basin, where the cryolithic zone is discontinuous, not only ground waters in seasonally thawing layers, but also continuous taliks and subpermafrost waters participate in processes of river recharges. As a result, a greater biological productivity of vegetation cover does not have any effect on ground-water supply and river recharge processes. If a steady climate warming is provided, a continuous cryolithic zone can presumably degrade into a discontinuous and then into an island-type permafrost layer. Under such a scenario, there will be a general increase in the total runoff and its subsurface constituent. From geoecological viewpoints, a greater runoff will have quite positive effects, whereas some

  18. Absolute humidity and the seasonal onset of influenza in the continental United States.

    Directory of Open Access Journals (Sweden)

    Jeffrey Shaman

    2010-02-01

    Full Text Available Much of the observed wintertime increase of mortality in temperate regions is attributed to seasonal influenza. A recent reanalysis of laboratory experiments indicates that absolute humidity strongly modulates the airborne survival and transmission of the influenza virus. Here, we extend these findings to the human population level, showing that the onset of increased wintertime influenza-related mortality in the United States is associated with anomalously low absolute humidity levels during the prior weeks. We then use an epidemiological model, in which observed absolute humidity conditions temper influenza transmission rates, to successfully simulate the seasonal cycle of observed influenza-related mortality. The model results indicate that direct modulation of influenza transmissibility by absolute humidity alone is sufficient to produce this observed seasonality. These findings provide epidemiological support for the hypothesis that absolute humidity drives seasonal variations of influenza transmission in temperate regions.

  19. Lake seasonality across the Tibetan Plateau and their varying relationship with regional mass changes and local hydrology

    Science.gov (United States)

    Lei, Yanbin; Yao, Tandong; Yang, Kun; Sheng, Yongwei; Kleinherenbrink, Marcel; Yi, Shuang; Bird, Broxton W.; Zhang, Xiaowen; Zhu, La; Zhang, Guoqing

    2017-01-01

    The recent growth and deepening of inland lakes in the Tibetan Plateau (TP) may be a salient indicator of the consequences of climate change. The seasonal dynamics of these lakes is poorly understood despite this being potentially crucial for disentangling contributions from glacier melt and precipitation, which are all sensitive to climate, to lake water budget. Using in situ observations, satellite altimetry and gravimetry data, we identified two patterns of lake level seasonality. In the central, northern, and northeastern TP, lake levels are characterized by considerable increases during warm seasons and decreases during cold seasons, which is consistent with regional mass changes related to monsoon precipitation and evaporation. In the northwestern TP, however, lake levels exhibit dramatic increases during both warm and cold seasons, which deviate from regional mass changes. This appears to be more connected with high spring snowfall and large summer glacier melt. The variable lake level response to different drivers indicates heterogeneous sensitivity to climate change between the northwestern TP and other regions.

  20. [Excess mortality associated with influenza in Spain in winter 2012].

    Science.gov (United States)

    León-Gómez, Inmaculada; Delgado-Sanz, Concepción; Jiménez-Jorge, Silvia; Flores, Víctor; Simón, Fernando; Gómez-Barroso, Diana; Larrauri, Amparo; de Mateo Ontañón, Salvador

    2015-01-01

    An excess of mortality was detected in Spain in February and March 2012 by the Spanish daily mortality surveillance system and the «European monitoring of excess mortality for public health action» program. The objective of this article was to determine whether this excess could be attributed to influenza in this period. Excess mortality from all causes from 2006 to 2012 were studied using time series in the Spanish daily mortality surveillance system, and Poisson regression in the European mortality surveillance system, as well as the FluMOMO model, which estimates the mortality attributable to influenza. Excess mortality due to influenza and pneumonia attributable to influenza were studied by a modification of the Serfling model. To detect the periods of excess, we compared observed and expected mortality. In February and March 2012, both the Spanish daily mortality surveillance system and the European mortality surveillance system detected a mortality excess of 8,110 and 10,872 deaths (mortality ratio (MR): 1.22 (95% CI:1.21-1.23) and 1.32 (95% CI: 1.29-1.31), respectively). In the 2011-12 season, the FluMOMO model identified the maximum percentage (97%) of deaths attributable to influenza in people older than 64 years with respect to the mortality total associated with influenza (13,822 deaths). The rate of excess mortality due to influenza and pneumonia and respiratory causes in people older than 64 years, obtained by the Serfling model, also reached a peak in the 2011-2012 season: 18.07 and 77.20, deaths per 100,000 inhabitants, respectively. A significant increase in mortality in elderly people in Spain was detected by the Spanish daily mortality surveillance system and by the European mortality surveillance system in the winter of 2012, coinciding with a late influenza season, with a predominance of the A(H3N2) virus, and a cold wave in Spain. This study suggests that influenza could have been one of the main factors contributing to the mortality excess

  1. Effects of diurnal temperature range on mortality in Hefei city, China

    Science.gov (United States)

    Tang, Jing; Xiao, Chang-chun; Li, Yu-rong; Zhang, Jun-qing; Zhai, Hao-yuan; Geng, Xi-ya; Ding, Rui; Zhai, Jin-xia

    2017-12-01

    Although several studies indicated an association between diurnal temperature range (DTR) and mortality, the results about modifiers are inconsistent, and few studies were conducted in developing inland country. This study aims to evaluate the effects of DTR on cause-specific mortality and whether season, gender, or age might modify any association in Hefei city, China, during 2007-2016. Quasi-Poisson generalized linear regression models combined with a distributed lag non-linear model (DLNM) were applied to evaluate the relationships between DTR and non-accidental, cardiovascular, and respiratory mortality. We observed a J-shaped relationship between DTR and cause-specific mortality. With a DTR of 8.3 °C as the reference, the cumulative effects of extremely high DTR were significantly higher for all types of mortality than effects of lower or moderate DTR in full year. When stratified by season, extremely high DTR in spring had a greater impact on all cause-specific mortality than other three seasons. Male and the elderly (≥ 65 years) were consistently more susceptible to extremely high DTR effect than female and the youth (< 65 years) for non-accidental and cardiovascular mortality. To the contrary, female and the youth were more susceptible to extremely high DTR effect than male and the elderly for respiratory morality. The study suggests that extremely high DTR is a potential trigger for non-accidental mortality in Hefei city, China. Our findings also highlight the importance of protecting susceptible groups from extremely high DTR especially in the spring.

  2. Preliminary Results of a U.S. Deep South Warm Season Deep Convective Initiation Modeling Experiment using NASA SPoRT Initialization Datasets for Operational National Weather Service Local Model Runs

    Science.gov (United States)

    Medlin, Jeffrey M.; Wood, Lance; Zavodsky, Brad; Case, Jon; Molthan, Andrew

    2012-01-01

    The initiation of deep convection during the warm season is a forecast challenge in the relative high instability and low wind shear environment of the U.S. Deep South. Despite improved knowledge of the character of well known mesoscale features such as local sea-, bay- and land-breezes, observations show the evolution of these features fall well short in fully describing the location of first initiates. A joint collaborative modeling effort among the NWS offices in Mobile, AL, and Houston, TX, and NASA s Short-term Prediction Research and Transition (SPoRT) Center was undertaken during the 2012 warm season to examine the impact of certain NASA produced products on the Weather Research and Forecasting Environmental Modeling System. The NASA products were: a 4-km Land Information System data, a 1-km sea surface temperature analysis, and a 4-km greenness vegetation fraction analysis. Similar domains were established over the southeast Texas and Alabama coastlines, each with a 9 km outer grid spacing and a 3 km inner nest spacing. The model was run at each NWS office once per day out to 24 hours from 0600 UTC, using the NCEP Global Forecast System for initial and boundary conditions. Control runs without the NASA products were made at the NASA SPoRT Center. The NCAR Model Evaluation Tools verification package was used to evaluate both the forecast timing and location of the first initiates, with a focus on the impacts of the NASA products on the model forecasts. Select case studies will be presented to highlight the influence of the products.

  3. Magnitude and pattern of Arctic warming governed by the seasonality of radiative forcing

    NARCIS (Netherlands)

    Bintanja, R.; Krikken, F.

    2016-01-01

    Observed and projected climate warming is strongest in the Arctic regions, peaking in autumn/winter. Attempts to explain this feature have focused primarily on identifying the associated climate feedbacks, particularly the ice-Albedo and lapse-rate feedbacks. Here we use a state-of-The-Art global

  4. Seeding method influences warm-season grass abundance and distribution but not local diversity in grassland restoration

    Science.gov (United States)

    Yurkonis, Kathryn A.; Wilsey, Brian J.; Moloney, Kirk A.; Drobney, Pauline; Larson, Diane L.

    2010-01-01

    Ecological theory predicts that the arrangement of seedlings in newly restored communities may influence future species diversity and composition. We test the prediction that smaller distances between neighboring seeds in drill seeded grassland plantings would result in lower species diversity, greater weed abundance, and larger conspecific patch sizes than otherwise similar broadcast seeded plantings. A diverse grassland seed mix was either drill seeded, which places seeds in equally spaced rows, or broadcast seeded, which spreads seeds across the ground surface, into 24 plots in each of three sites in 2005. In summer 2007, we measured species abundance in a 1 m2 quadrat in each plot and mapped common species within the quadrat by recording the most abundant species in each of 64 cells. Quadrat-scale diversity and weed abundance were similar between drilled and broadcast plots, suggesting that processes that limited establishment and controlled invasion were not affected by such fine-scale seed distribution. However, native warm-season (C4) grasses were more abundant and occurred in less compact patches in drilled plots. This difference in C4 grass abundance and distribution may result from increased germination or vegetative propagation of C4 grasses in drilled plots. Our findings suggest that local plant density may control fine-scale heterogeneity and species composition in restored grasslands, processes that need to be further investigated to determine whether seed distributions can be manipulated to increase diversity in restored grasslands.

  5. Changes in the Effect of Heat on Mortality in the Last 20 Years in Nine European Cities. Results from the PHASE Project.

    Science.gov (United States)

    de' Donato, Francesca K; Leone, Michela; Scortichini, Matteo; De Sario, Manuela; Katsouyanni, Klea; Lanki, Timo; Basagaña, Xavier; Ballester, Ferran; Åström, Christofer; Paldy, Anna; Pascal, Mathilde; Gasparrini, Antonio; Menne, Bettina; Michelozzi, Paola

    2015-12-08

    The European project PHASE aims to evaluate patterns of change in the temperature-mortality relationship and in the number of deaths attributable to heat in nine European cities in two periods, before and after summer 2003 (1996-2002 and 2004-2010). We performed age-specific Poisson regression models separately in the two periods, controlling for seasonality, air pollution and time trends. Distributed lag non-linear models were used to estimate the Relative Risks of daily mortality for increases in mean temperature from the 75th to 99th percentile of the summer distribution for each city. In the recent period, a reduction in the mortality risk associated to heat was observed only in Athens, Rome and Paris, especially among the elderly. Furthermore, in terms of heat-attributable mortality, 985, 787 and 623 fewer deaths were estimated, respectively, in the three cities. In Helsinki and Stockholm, there is a suggestion of increased heat effect. Noteworthy is that an effect of heat was still present in the recent years in all cities, ranging from +11% to +35%. In Europe, considering the warming observed in recent decades and population ageing, effective intervention measures should be promoted across countries, especially targeting vulnerable subgroups of the population with lower adaptive resources.

  6. Evaluation of seasonal exergy efficiency of air handing unit

    Directory of Open Access Journals (Sweden)

    Kęstutis Genys

    2015-10-01

    Full Text Available The article deals with the air handling unit seasonal exergy efficiency. TRNSYS simulation tool is used to evaluate it. The object of research is air treatment device used to treat an air for the ventilation of laboratory. The mathematical model of air handling unit using TRNSYS simulation tool was developed when the technical parameters of air handling unit and energy exchange in it were analysed. The developed model according to the made observations during the warm and cold periods was tested and validation of elements was performed. The simulation of air handling unit operation after the verification of reliability and permitted tolerances was performed. The control mechanisim which allows simulating the operation of air handling unit during cold and warm periods of the year was made. The mathematical algorithm for calculation of air handling unit exergy efficiency coefficient applying the principles of exergy analysis was developed. The seasonal exergy efficiency of air handling unit equal to 3.94 percent during the simulation was obtained.

  7. Seasonal growth and mortality of juveniles of Lampsilis fasciola (Bivalvia: Unionidae) released to a fish hatchery raceway

    Science.gov (United States)

    Hanlon, Shane D.; Neves, Richard J.

    2006-01-01

    Recent efforts to restore remnant or extirpated populations of freshwater mussels have focused on artificial propagation as an effective and practical conservation strategy. Although artificially cultured juveniles have been produced and released to the wild at various times of the year, no study has investigated the best time of year to release these juveniles. Newly metamorphosed juveniles of the wavyrayed lampmussel (Lampsilis fasciola) were released into a stream-fed fish hatchery raceway during March, June, and September. Growth and survival rates were measured 32, 52, 72, and 92 days post-metamorphosis. Juveniles released in June experienced the greatest growth and survival rates. Juveniles released in September and March experienced high mortality within the first month of release and exhibited poor growth in the cool water conditions typical of those seasons. Overwinter survival exhibited a size-dependent relationship.

  8. Economic and conservation implications of converting exotic forages to native warm-season grass

    Directory of Open Access Journals (Sweden)

    Adrian P. Monroe

    2017-07-01

    Full Text Available Intensive agriculture can have negative environmental consequences such as nonpoint source pollution and the simplification of biotic communities, and land sharing posits that conservation can be enhanced by integrating agricultural productivity and biodiversity on the same land. In the Southeastern United States, native warm-season grasses (NWSG may be a land sharing alternative to exotic forages currently in production because of greater livestock gains with lower fertilizer inputs, and habitat for grassland birds. However, uncertainty regarding costs and risk poses an important barrier to incorporating NWSG in livestock operations. We evaluated the economic and conservation implications of NWSG conversion among small, operational-scale pastures (6.8–10.5 ha during 2011–2012 at the Prairie Research Unit in Monroe Co., Mississippi (USA. We used partial budgets to compare the marginal rate of return (MRRe from converting exotic grass pastures to either a NWSG monoculture of Indiangrass (Sorghastrum nutans or a NWSG mix of Indiangrass, little bluestem (Schizachyrium scoparium, and big bluestem (Andropogon gerardii. We similarly compared changes in productivity of dickcissels (Spiza americana, a grassland bird specializing in tall structure. Average daily gain (ADG of steers and revenue were consistently higher for NWSG treatments than exotic grass pasture, but ADG declined between years. Indiangrass pastures yielded consistently positive MRRe, indicating producers would receive 16–24% return on investment. Marginal rate of return was lower for mixed NWSG (−12 to 3%, driven by slightly lower livestock ADG and higher establishment costs than for Indiangrass. Sensitivity analyses indicated that MRRe also was influenced by cattle selling price. Conversely, mixed NWSG increased dickcissel productivity by a greater degree than Indiangrass per amount invested in NWSG conversion, suggesting a tradeoff between livestock and dickcissel production

  9. Outdoor thermal comfort in public space in warm-humid Guayaquil, Ecuador

    Science.gov (United States)

    Johansson, Erik; Yahia, Moohammed Wasim; Arroyo, Ivette; Bengs, Christer

    2018-03-01

    The thermal environment outdoors affects human comfort and health. Mental and physical performance is reduced at high levels of air temperature being a problem especially in tropical climates. This paper deals with human comfort in the warm-humid city of Guayaquil, Ecuador. The main aim was to examine the influence of urban micrometeorological conditions on people's subjective thermal perception and to compare it with two thermal comfort indices: the physiologically equivalent temperature (PET) and the standard effective temperature (SET*). The outdoor thermal comfort was assessed through micrometeorological measurements of air temperature, humidity, mean radiant temperature and wind speed together with a questionnaire survey consisting of 544 interviews conducted in five public places of the city during both the dry and rainy seasons. The neutral and preferred values as well as the upper comfort limits of PET and SET* were determined. For both indices, the neutral values and upper thermal comfort limits were lower during the rainy season, whereas the preferred values were higher during the rainy season. Regardless of season, the neutral values of PET and SET* are above the theoretical neutral value of each index. The results show that local people accept thermal conditions which are above acceptable comfort limits in temperate climates and that the subjective thermal perception varies within a wide range. It is clear, however, that the majority of the people in Guayaquil experience the outdoor thermal environment during daytime as too warm, and therefore, it is important to promote an urban design which creates shade and ventilation.

  10. Impacts of +2 °C global warming on winter tourism demand in Europe

    NARCIS (Netherlands)

    Damm, Andrea; Greuell, Wouter; Landgren, Oskar; Prettenthaler, Franz

    2017-01-01

    Increasing temperatures and snow scarce winter seasons challenge the winter tourism industry. In this study the impacts of +2 °C global warming on winter tourism demand in Europe's ski tourism related NUTS-3 regions are quantified. Using time series regression models, the relationship between

  11. Microclimate impacts of passive warming methods in Antarctica: implications for climate change studies

    NARCIS (Netherlands)

    Bokhorst, S.; Huiskes, A.H.L.; Convey, P.; Sinclair, B.J.; Lebouvier, M.; van de Vijver, B.; Wall, D.H.

    2011-01-01

    Passive chambers are used to examine the impacts of summer warming in Antarctica but, so far, impacts occurring outside the growing season, or related to extreme temperatures, have not been reported, despite their potentially large biological significance. In this review, we synthesise and discuss

  12. Effects of different re-warm up activities in football players' performance.

    Directory of Open Access Journals (Sweden)

    Eduardo Abade

    Full Text Available Warm up routines are commonly used to optimize football performance and prevent injuries. Yet, official pre-match protocols may require players to passively rest for approximately 10 to 15 minutes between the warm up and the beginning of the match. Therefore, the aim of this study was to explore the effect of different re-warm up activities on the physical performance of football players. Twenty-Two Portuguese elite under-19 football players participated in the study conducted during the competitive season. Different re-warm up protocols were performed 6 minutes after the same standardized warm up in 4 consecutive days in a crossover controlled approach: without, eccentric, plyometric and repeated changes of direction. Vertical jump and Sprint performances were tested immediately after warm up and 12 minutes after warm up. Results showed that repeated changes of direction and plyometrics presented beneficial effects to jump and sprint. Different practical implications may be taken from the eccentric protocol since a vertical jump impairment was observed, suggesting a possibly harmful effect. The absence of re-warm up activities may be detrimental to players' physical performance. However, the inclusion of re-warm up prior to match is a complex issue, since the manipulation of volume, intensity and recovery may positively or negatively affect the subsequent performance. In fact, this exploratory study shows that eccentric exercise may be harmful for physical performance when performed prior a football match. However, plyometric and repeated changes of direction exercises seem to be simple, quick and efficient activities to attenuate losses in vertical jump and sprint capacity after warm up. Coaches should aim to develop individual optimal exercise modes in order to optimize physical performance after re warm activities.

  13. An assessment of global warming stress on Caribbean coral reef ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, D.K.; Hendec, J.C.; Mendez, A. (NOAA, Miami, FL (USA). Atlantic Oceanography and Meteorology Laboratory)

    1992-07-01

    There is evidence that stress on coral reef ecosystems in the Caribbean region is increasing. Recently numerous authors have stated that the major stress results from 'abnormally high' seasonal sea surface temperatures (SST) and have implicated global warming as a cause, stating that recent episodes of coral bleaching result therefrom. However, an analysis of available SST data sets shows no discernible warming trend that could cause an increase in coral bleaching. Given the lack of long-term records synoptic with observations of coral ecosystem health, there is insufficient evidence available to label temperatures observed in coincidence with recent regional bleaching events as 'abnormally' high.

  14. An assessment of global warming stress on Caribbean coral reef ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, D K; Hendec, J C; Mendez, A [NOAA, Miami, FL (USA). Atlantic Oceanography and Meteorology Laboratory

    1992-07-01

    There is evidence that stress on coral reef ecosystems in the Caribbean region is increasing. Recently numerous authors have stated that the major stress results from 'abnormally high' seasonal sea surface temperatures (SST) and have implicated global warming as a cause, stating that recent episodes of coral bleaching result therefrom. However, an analysis of available SST data sets shows no discernible warming trend that could cause an increase in coral bleaching. Given the lack of long-term records synoptic with observations of coral ecosystem health, there is insufficient evidence available to label temperatures observed in coincidence with recent regional bleaching events as 'abnormally' high.

  15. Seasonal temperature extremes in Potsdam

    Science.gov (United States)

    Kundzewicz, Zbigniew; Huang, Shaochun

    2010-12-01

    The awareness of global warming is well established and results from the observations made on thousands of stations. This paper complements the large-scale results by examining a long time-series of high-quality temperature data from the Secular Meteorological Station in Potsdam, where observation records over the last 117 years, i.e., from January 1893 are available. Tendencies of change in seasonal temperature-related climate extremes are demonstrated. "Cold" extremes have become less frequent and less severe than in the past, while "warm" extremes have become more frequent and more severe. Moreover, the interval of the occurrence of frost has been decreasing, while the interval of the occurrence of hot days has been increasing. However, many changes are not statistically significant, since the variability of temperature indices at the Potsdam station has been very strong.

  16. Trends in airborne pollen and pollen-season-related features of anemophilous species in Jaen (south Spain): A 23-year perspective

    Science.gov (United States)

    Ruiz-Valenzuela, Luis; Aguilera, Fátima

    2018-05-01

    Over the last few decades, global warming is prompting phenological changes in numerous plant species across Europe, and a trend towards rising airborne pollen concentrations has been detected. This study, focused on the most frequent pollen types from arboreal and herbaceous species in the airborne spectrum of Jaen (southern Spain), revealed significant changes in airborne pollen intensity and duration of the pollen season over the 23-year study period. Here Cupressaceae, Olea, Pinus, Platanus, Quercus as arboreal taxa and Plantago as herbaceous taxa were the most important with notable changes of at least three pollen season characteristics. Airborne pollen trends from arboreal taxa with high to very high allergenic potential are rising in line with the local temperature increasing trend, and their pollen seasons tend to end later and last longer. However, both the pollen concentrations and the duration of the pollen season of some herbaceous taxa are declining. The climate conditions projected for south Europe under different greenhouse emissions scenarios could continue to prompt greater pollen release and longer pollen season in tree species, especially those that flowering in winter and early spring, but these warming trends might be adverse for the local development of some herbaceous species and favorable for others sharing the same ecological niche. If similar warming trends accompany long-term climate change, greater exposure times to seasonal allergens may occur with subsequent effects on health.

  17. Retrospective analysis of trends and production factors associated with sow mortality on swine-breeding farms in USA.

    Science.gov (United States)

    Koketsu, Y

    2000-09-01

    Of the 825 pig farms in USA that mailed in their electronic file containing production records, 604 farms were used to observe breeding-female mortality risk and related factors (herd size, lactation length, parity and season). Multiple regression was used to determine factors associated with annual mortality risk. Analyses of variance were used for comparisons of mortality risks among parity and season groups. Average annual mortality risks during the 1997 period was 5.68%. Average breeding-female inventories and average lactation length on USA farms were 733 and 18.3 days, respectively. Higher annual breeding-female mortality risk was associated with larger herd size, greater parity at farrowing and shorter lactation length (P500 females, mortality risk increases by 0.44%. Older parity was associated with higher mortality risks. Summer season was also associated with higher mortality risk. Using five-years' records on 270 farms, annual mortality risk in 1997 was higher than those of 1993 and 1994, while average breeding-female inventory increased and lactation length decreased. It is recommended that producers, especially in large herds, pay more attention to breeding females.

  18. In a warming climate, just how predictable are temperature extremes at weather and seasonal time scales?

    CSIR Research Space (South Africa)

    Landman, WA

    2011-10-01

    Full Text Available stream_source_info Landman7_2011.pdf.txt stream_content_type text/plain stream_size 3538 Content-Encoding ISO-8859-1 stream_name Landman7_2011.pdf.txt Content-Type text/plain; charset=ISO-8859-1 In a warming climate... at UK Met Office N9 members SA Japan UKUSA USA Brazil* SA SASA * IBSA-Ocean In use Near future Far future VCM/UTCM ENSEMBLES Strong anthropogenically forced warming trends have been observed over southern Africa and are projected...

  19. Seasonal Influenza: An Overview

    Science.gov (United States)

    Li, Christina; Freedman, Marian

    2009-01-01

    Seasonal influenza is a major cause of morbidity and mortality in the United States. It also has major social and economic consequences in the form of high rates of absenteeism from school and work as well as significant treatment and hospitalization costs. In fact, annual influenza epidemics and the resulting deaths and lost days of productivity…

  20. Long-term responses of the endemic reef-builder Cladocora caespitosa to Mediterranean warming.

    Directory of Open Access Journals (Sweden)

    Diego K Kersting

    Full Text Available Recurrent climate-induced mass-mortalities have been recorded in the Mediterranean Sea over the past 15 years. Cladocora caespitosa, the sole zooxanthellate scleractinian reef-builder in the Mediterranean, is among the organisms affected by these episodes. Extensive bioconstructions of this endemic coral are very rare at the present time and are threatened by several stressors. In this study, we assessed the long-term response of this temperate coral to warming sea-water in the Columbretes Islands (NW Mediterranean and described, for the first time, the relationship between recurrent mortality events and local sea surface temperature (SST regimes in the Mediterranean Sea. A water temperature series spanning more than 20 years showed a summer warming trend of 0.06°C per year and an increased frequency of positive thermal anomalies. Mortality resulted from tissue necrosis without massive zooxanthellae loss and during the 11-year study, necrosis was recorded during nine summers separated into two mortality periods (2003-2006 and 2008-2012. The highest necrosis rates were registered during the first mortality period, after the exceptionally hot summer of 2003. Although necrosis and temperature were significantly associated, the variability in necrosis rates during summers with similar thermal anomalies pointed to other acting factors. In this sense, our results showed that these differences were more closely related to the interannual temperature context and delayed thermal stress after extreme summers, rather than to acclimatisation and adaption processes.

  1. Soil-surface CO2 flux and growth in a boreal Norway spruce stand: Effects of soil warming and nutrition

    International Nuclear Information System (INIS)

    Stroemgren, M.

    2001-01-01

    Global warming is predicted to affect the carbon balance of forests. A change in the carbon balance would give a positive or negative feedback to the greenhouse effect, which would affect global warming. The effects of long-term soil warming on growth, nutrient and soil-surface CO 2 flux (R) dynamics were studied in irrigated (I) and irrigated-fertilised (IL) stands of Norway spruce in northern Sweden. Soil temperature on heated plots (Ih and ILh) was maintained 5 deg C above that on unheated plots (Ic and ILc) from May to October, by heating cables. After six years' soil warming, stemwood production increased by 100% and 50% in the I and IL treatment, respectively. The main production increase occurred at the beginning of the season, probably as an effect of the earlier increase in soil temperature. In the 1h treatment, however, the growth increase was evident during the entire season. The effect of increased nitrogen (N) mineralisation on annual growth appeared to be stronger than the direct effect of warming. From 1995-2000, the total amount of N stored in aboveground tree parts increased by 100 and 475 kg N/ha on Ic and ILc plots, respectively. During the same period, 450 kg N fertiliser was added to the ILc plot. Soil warming increased the total amount of N stored in aboveground tree parts by 50 kg N/ha, independently of nutrient treatment. Soil warming did not significantly increase R, except in early spring, when R was 30-50% higher on heated compared to unheated plots. The extended growing season, however, increased annual respiration (RA) by 12-30% throughout. RA losses were estimated to be 0.6-0.7 kg C/ha/year. Use of relationships between R and soil temperature, derived from unheated plots, overestimated RA on heated plots by 50-80%. These results suggest that acclimation of root or microbial respiration or both to temperature had occurred, but the exact process(es) and their relative contribution are still unclear. In conclusion, the study showed that

  2. Antarctica: Cooling or Warming?

    Science.gov (United States)

    Bunde, Armin; Ludescher, Josef; Franzke, Christian

    2013-04-01

    We consider the 14 longest instrumental monthly mean temperature records from the Antarctica and analyse their correlation properties by wavelet and detrended fluctuation analysis. We show that the stations in the western and the eastern part of the Antarctica show significant long-term memory governed by Hurst exponents close to 0.8 and 0.65, respectively. In contrast, the temperature records at the inner part of the continent (South Pole and Vostok), resemble white noise. We use linear regression to estimate the respective temperature differences in the records per decade (i) for the annual data, (ii) for the summer and (iii) for the winter season. Using a recent approach by Lennartz and Bunde [1] we estimate the respective probabilities that these temperature differences can be exceeded naturally without inferring an external (anthropogenic) trend. We find that the warming in the western part of the continent and the cooling at the South Pole is due to a gradually changes in the cold extremes. For the winter months, both cooling and warming are well outside the 95 percent confidence interval, pointing to an anthropogenic origin. In the eastern Antarctica, the temperature increases and decreases are modest and well within the 95 percent confidence interval. [1] S. Lennartz and A. Bunde, Phys. Rev. E 84, 021129 (2011)

  3. Observational Analysis of Cloud and Precipitation in Midlatitude Cyclones: Northern Versus Southern Hemisphere Warm Fronts

    Science.gov (United States)

    Naud, Catherine M.; Posselt, Derek J.; van den Heever, Susan C.

    2012-01-01

    Extratropical cyclones are responsible for most of the precipitation and wind damage in the midlatitudes during the cold season, but there are still uncertainties on how they will change in a warming climate. An ubiquitous problem amongst General Circulation Models (GCMs) is a lack of cloudiness over the southern oceans that may be in part caused by a lack of clouds in cyclones. We analyze CloudSat, CALIPSO and AMSR-E observations for 3 austral and boreal cold seasons and composite cloud frequency of occurrence and precipitation at the warm fronts for northern and southern hemisphere oceanic cyclones. We find that cloud frequency of occurrence and precipitation rate are similar in the early stage of the cyclone life cycle in both northern and southern hemispheres. As cyclones evolve and reach their mature stage, cloudiness and precipitation at the warm front increase in the northern hemisphere but decrease in the southern hemisphere. This is partly caused by lower amounts of precipitable water being available to southern hemisphere cyclones, and smaller increases in wind speed as the cyclones evolve. Southern hemisphere cloud occurrence at the warm front is found to be more sensitive to the amount of moisture in the warm sector than to wind speeds. This suggests that cloudiness in southern hemisphere storms may be more susceptible to changes in atmospheric water vapor content, and thus to changes in surface temperature than their northern hemisphere counterparts. These differences between northern and southern hemisphere cyclones are statistically robust, indicating A-Train-based analyses as useful tools for evaluation of GCMs in the next IPCC report.

  4. The influence of season and living environment on children's urinary 1-hydroxypyrene levels in Ulaanbaatar, Mongolia.

    Science.gov (United States)

    Chen, Yi-Ting; Huang, Yu-Kai; Luvsan, Munkh-Erdene; Gombojav, Enkhjargal; Ochir, Chimedsuren; Bulgan, Jargal; Chan, Chang-Chuan

    2015-02-01

    Heating indoor living environments elevates air pollution in Ulaanbaatar, Mongolia. This study was conducted to investigate the influence of season and living environment on children's urinary 1-hydroxypyrene (1-OHP) levels in Ulaanbaatar, Mongolia. Our study subjects were 320 children aged 11-15 years living in gers, brick houses and apartments, in ger and non-ger areas of Ulaanbaatar. Spot urine samples and questionnaires were collected three times from each subject in three seasons, September (warm) and December (cold) in 2011 and March (moderate) in 2012. Urinary 1-OHP was analyzed by high-performance liquid chromatography with fluorescent detection (HPLC/FLD). Generalized estimating equation (GEE) models were applied to estimate the seasonal and residential effects on 1-OHP levels, adjusting for demographic and environmental factors. Children's urinary 1-OHP levels showed significant seasonal differences with 0.30 ± 0.57 μmol/mol creatinine in cold season, 0.14 ± 0.12 μmol/mol creatinine in moderate season, and 0.14 ± 0.21 μmol/mol creatinine in warm season. After controlling confounding factors, the GEE model showed that season, living area, and housing type had significant influence on children's urinary 1-OHP levels. Urinary 1-OHP levels in the cold and moderate seasons were, respectively 2.13 and 1.37 times higher than the warm season. Urinary 1-OHP levels for children living in ger areas were 1.27 times higher than those living in non-ger areas. Children who lived in gers or brick houses had 1.58 and 1.34 times higher 1-OHP levels, respectively, compared with those living in apartments. Children's urinary 1-OHP levels were associated with either estimated NO2 or SO2 concentrations at their home addresses in Ulaanbaatar. Mongolian children's urinary 1-OHP levels were significantly elevated during the cold season, and for those living in ger areas, gers, or brick houses in Ulaanbaatar. Children's urinary 1-OHP levels were associated PAH co

  5. Mortality following Stroke, the Weekend Effect and Related Factors: Record Linkage Study.

    Directory of Open Access Journals (Sweden)

    Stephen E Roberts

    Full Text Available Increased mortality following hospitalisation for stroke has been reported from many but not all studies that have investigated a 'weekend effect' for stroke. However, it is not known whether the weekend effect is affected by factors including hospital size, season and patient distance from hospital.To assess changes over time in mortality following hospitalisation for stroke and how any increased mortality for admissions on weekends is related to factors including the size of the hospital, seasonal factors and distance from hospital.A population study using person linked inpatient, mortality and primary care data for stroke from 2004 to 2012. The outcome measures were, firstly, mortality at seven days and secondly, mortality at 30 days and one year.Overall mortality for 37 888 people hospitalised following stroke was 11.6% at seven days, 21.4% at 30 days and 37.7% at one year. Mortality at seven and 30 days fell significantly by 1.7% and 3.1% per annum respectively from 2004 to 2012. When compared with week days, mortality at seven days was increased significantly by 19% for admissions on weekends, although the admission rate was 21% lower on weekends. Although not significant, there were indications of increased mortality at seven days for weekend admissions during winter months (31%, in community (81% rather than large hospitals (8% and for patients resident furthest from hospital (32% for distances of >20 kilometres. The weekend effect was significantly increased (by 39% for strokes of 'unspecified' subtype.Mortality following stroke has fallen over time. Mortality was increased for admissions at weekends, when compared with normal week days, but may be influenced by a higher stroke severity threshold for admission on weekends. Other than for unspecified strokes, we found no significant variation in the weekend effect for hospital size, season and distance from hospital.

  6. Propagation of planktonic copepods: production and mortality of eggs

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Møhlenberg, Flemming; Tiselius, Peter

    1988-01-01

    Data on fecundity and egg mortality of neritic copepods were collected in various seasons, areas and under various hydrographical conditions. On a seasonal basis variations in fecundity (F) were related to temperature rather than to the abundance of phytoplankton (P). However, a strong correlation...... between F and P was evident when water column stability varied horisontally or temporally (i.e. at a tidal front or subsequent to a storm). Estimated specific egg-mortalities were variable and occasionally very severe, up to 9.1 d−1, implying that down to 10−4% of the eggs survive to hatching...

  7. Coupled prediction of flood response and debris flow initiation during warm- and cold-season events in the Southern Appalachians, USA

    Science.gov (United States)

    Tao, J.; Barros, A. P.

    2014-01-01

    Debris flows associated with rainstorms are a frequent and devastating hazard in the Southern Appalachians in the United States. Whereas warm-season events are clearly associated with heavy rainfall intensity, the same cannot be said for the cold-season events. Instead, there is a relationship between large (cumulative) rainfall events independently of season, and thus hydrometeorological regime, and debris flows. This suggests that the dynamics of subsurface hydrologic processes play an important role as a trigger mechanism, specifically through soil moisture redistribution by interflow. We further hypothesize that the transient mass fluxes associated with the temporal-spatial dynamics of interflow govern the timing of shallow landslide initiation, and subsequent debris flow mobilization. The first objective of this study is to investigate this relationship. The second objective is to assess the physical basis for a regional coupled flood prediction and debris flow warning system. For this purpose, uncalibrated model simulations of well-documented debris flows in headwater catchments of the Southern Appalachians using a 3-D surface-groundwater hydrologic model coupled with slope stability models are examined in detail. Specifically, we focus on two vulnerable headwater catchments that experience frequent debris flows, the Big Creek and the Jonathan Creek in the Upper Pigeon River Basin, North Carolina, and three distinct weather systems: an extremely heavy summertime convective storm in 2011; a persistent winter storm lasting several days; and a severe winter storm in 2009. These events were selected due to the optimal availability of rainfall observations; availability of detailed field surveys of the landslides shortly after they occurred, which can be used to evaluate model predictions; and because they are representative of events that cause major economic losses in the region. The model results substantiate that interflow is a useful prognostic of conditions

  8. The association of meteorological factors and mortality in rural Bangladesh, 1983–2009

    Directory of Open Access Journals (Sweden)

    Peter Kim Streatfield

    2012-11-01

    Full Text Available Introduction: While the association of weather and mortality has been well documented for moderate climate zones, little is known about sub-tropical zones, particularly Bangladesh. This study aims to assess the short-term relationship of temperature and rainfall on daily mortality after controlling for seasonality and time-trends. The study used data from Matlab, Bangladesh, where a rigorous health and demographic surveillance system (HDSS has been operational since 1966. Material and methods: Matlab HDSS data on mortality and population for the period 1983–2009 were used. Weather data for the same period were obtained from a nearby government weather station. Time series Poisson regression with cubic spline functions was applied allowing for lagged effects of weather and extreme weather events on mortality, and controlling for time trends and seasonal patterns. Analysis was carried out using R statistical software. Results: Both temperature and rainfall showed strong seasonal patterns, explaining a significant part of mortality in all age groups. After adjusting for seasonality and trend, mortality and temperature show a U-shaped pattern; below a temperature of around 29°C, a decrease in temperature resulted in an increase in mortality, whereas above 29°C, increased temperature resulted in increased mortality. The strongest negative mortality temperature association was observed in the elderly (5.4% increase with every 1°C decrease in temperature at temperatures below 23°C, and the opposite trend was observed in the age groups 1–4 and 5–19 years old. At aggregate level, the rainfall–mortality association is statistically weak. However in the age group 5–19, a 0.6% increase in mortality per 1 mm additional rainfall was found, at rainfall levels over 100 mm per day. Multivariate analysis showed high mortality risks for women aged 20–59 years of age during cyclone episodes. Discussion: Weather and extreme weather were associated

  9. Transient turbid water mass reduces temperature-induced coral bleaching and mortality in Barbados

    Science.gov (United States)

    Vallès, Henri

    2016-01-01

    Global warming is seen as one of the greatest threats to the world’s coral reefs and, with the continued rise in sea surface temperature predicted into the future, there is a great need for further understanding of how to prevent and address the damaging impacts. This is particularly so for countries whose economies depend heavily on healthy reefs, such as those of the eastern Caribbean. Here, we compare the severity of bleaching and mortality for five dominant coral species at six representative reef sites in Barbados during the two most significant warm-water events ever recorded in the eastern Caribbean, i.e., 2005 and 2010, and describe prevailing island-scale sea water conditions during both events. In so doing, we demonstrate that coral bleaching and subsequent mortality were considerably lower in 2010 than in 2005 for all species, irrespective of site, even though the anomalously warm water temperature profiles were very similar between years. We also show that during the 2010 event, Barbados was engulfed by a transient dark green turbid water mass of riverine origin coming from South America. We suggest that reduced exposure to high solar radiation associated with this transient water mass was the primary contributing factor to the lower bleaching and mortality observed in all corals. We conclude that monitoring these episodic mesoscale oceanographic features might improve risk assessments of southeastern Caribbean reefs to warm-water events in the future. PMID:27326377

  10. Temperature response surfaces for mortality risk of tree species with future drought

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Henry D.; Barron-Gafford, Greg A.; Minor, Rebecca L.; Gardea, Alfonso A.; Bentley, Lisa Patrick; Law, Darin J.; Breshears, David D.; McDowell, Nate G.; Huxman, Travis E.

    2017-11-01

    Widespread, high levels of tree mortality, termed forest die-off, associated with drought and rising temperatures, are disrupting forests worldwide. Drought will likely become more frequent with climate change, but even without more frequent drought, higher temperatures can exacerbate tree water stress. The temperature sensitivity of drought-induced mortality of tree species has been evaluated experimentally for only single-step changes in temperature (ambient compared to ambient + increase) rather than as a response surface (multiple levels of temperature increase), which constrains our ability to relate changes in the driver with the biological response. Here we show that time-to-mortality during drought for seedlings of two western United States tree species, Pinus edulis (Engelm.) and Pinus ponderosa (Douglas ex C. Lawson), declined in continuous proportion with increasing temperature spanning a 7.7 °C increase. Although P. edulis outlived P. ponderosa at all temperatures, both species had similar relative declines in time-to-mortality as temperature increased (5.2% per °C for P. edulis; 5.8% per °C for P. ponderosa). When combined with the non-linear frequency distribution of drought duration—many more short droughts than long droughts—these findings point to a progressive increase in mortality events with global change due to warming alone and independent of additional changes in future drought frequency distributions. As such, dire future forest recruitment patterns are projected assuming the calculated 7-9 seedling mortality events per species by 2100 under business-as-usual warming occurs, congruent with additional vulnerability predicted for adult trees from stressors like pathogens and pests. Our progressive projection for increased mortality events was driven primarily by the non-linear shape of the drought duration frequency distribution, a common climate feature of drought-affected regions. These

  11. Temperature response surfaces for mortality risk of tree species with future drought

    Science.gov (United States)

    Adams, Henry D.; Barron-Gafford, Greg A.; Minor, Rebecca L.; Gardea, Alfonso A.; Bentley, Lisa Patrick; Law, Darin J.; Breshears, David D.; McDowell, Nate G.; Huxman, Travis E.

    2017-11-01

    Widespread, high levels of tree mortality, termed forest die-off, associated with drought and rising temperatures, are disrupting forests worldwide. Drought will likely become more frequent with climate change, but even without more frequent drought, higher temperatures can exacerbate tree water stress. The temperature sensitivity of drought-induced mortality of tree species has been evaluated experimentally for only single-step changes in temperature (ambient compared to ambient + increase) rather than as a response surface (multiple levels of temperature increase), which constrains our ability to relate changes in the driver with the biological response. Here we show that time-to-mortality during drought for seedlings of two western United States tree species, Pinus edulis (Engelm.) and Pinus ponderosa (Douglas ex C. Lawson), declined in continuous proportion with increasing temperature spanning a 7.7 °C increase. Although P. edulis outlived P. ponderosa at all temperatures, both species had similar relative declines in time-to-mortality as temperature increased (5.2% per °C for P. edulis; 5.8% per °C for P. ponderosa). When combined with the non-linear frequency distribution of drought duration—many more short droughts than long droughts—these findings point to a progressive increase in mortality events with global change due to warming alone and independent of additional changes in future drought frequency distributions. As such, dire future forest recruitment patterns are projected assuming the calculated 7-9 seedling mortality events per species by 2100 under business-as-usual warming occur, congruent with additional vulnerability predicted for adult trees from stressors like pathogens and pests. Our progressive projection for increased mortality events was driven primarily by the non-linear shape of the drought duration frequency distribution, a common climate feature of drought-affected regions. These results illustrate profound benefits for

  12. Time-series analysis of air pollution and cause-specific mortality

    NARCIS (Netherlands)

    Zmirou, D; Schwartz, J; Saez, M; Zanobetti, A; Wojtyniak, B; Touloumi, G; Spix, C; de Leon, AP; Le Moullec, Y; Bacharova, L; Schouten, J; Ponka, A; Katsouyanni, K

    Ten large European cities provided data on daily air pollution as well as mortality from respiratory and cardiovascular mortality. We used Poisson autoregressive models that controlled for trend, season, influenza epidemics, and meteorologic influences to assess the short-term effects of air

  13. Associations between ambient air pollution and daily mortality among elderly persons in Montreal, Quebec.

    Science.gov (United States)

    Goldberg, Mark S; Burnett, Richard T; Stieb, David M; Brophy, James M; Daskalopoulou, Stella S; Valois, Marie-France; Brook, Jeffrey R

    2013-10-01

    Persons with underlying health conditions may be at higher risk for the short-term effects of air pollution. We have extended our original mortality time series study in Montreal, Quebec, among persons 65 years of age and older, for an additional 10 years (1990-2003) to assess whether these associations persisted and to investigate new health conditions. We created subgroups of subjects diagnosed with major health conditions one year before death using billing and prescription data from the Quebec Health Insurance Plan. We used parametric log-linear Poisson models within the distributed lag non-linear models framework, that were adjusted for long-term temporal trends and daily maximum temperature, for which we assessed associations with NO2, O3, CO, SO2, and particles with aerodynamic diameters 2.5 μm in diameter or less (PM2.5). We found positive associations between daily non-accidental mortality and all air pollutants but O3 (e.g., for a cumulative effect over a 3-day lag, with a mean percent change (MPC) in daily mortality of 1.90% [95% confidence interval: 0.73, 3.08%] for an increase of the interquartile range (17.56 μg m(-3)) of NO2). Positive associations were found amongst persons having cardiovascular disease (cumulative MPC for an increase equal to the interquartile range of NO2=2.67%), congestive heart failure (MPC=3.46%), atrial fibrillation (MPC=4.21%), diabetes (MPC=3.45%), and diabetes and cardiovascular disease (MPC=3.50%). Associations in the warm season were also found for acute and chronic coronary artery disease, hypertension, and cancer. There was no persuasive evidence to conclude that there were seasonal associations for cerebrovascular disease, acute lower respiratory disease (defined within 2 months of death), airways disease, and diabetes and airways disease. These data indicate that individuals with certain health conditions, especially those with diabetes and cardiovascular disease, hypertension, atrial fibrillation, and cancer, may

  14. Atmospheric circulation and hydroclimate impacts of alternative warming scenarios for the Eocene

    Science.gov (United States)

    Carlson, Henrik; Caballero, Rodrigo

    2017-08-01

    Recent work in modelling the warm climates of the early Eocene shows that it is possible to obtain a reasonable global match between model surface temperature and proxy reconstructions, but only by using extremely high atmospheric CO2 concentrations or more modest CO2 levels complemented by a reduction in global cloud albedo. Understanding the mix of radiative forcing that gave rise to Eocene warmth has important implications for constraining Earth's climate sensitivity, but progress in this direction is hampered by the lack of direct proxy constraints on cloud properties. Here, we explore the potential for distinguishing among different radiative forcing scenarios via their impact on regional climate changes. We do this by comparing climate model simulations of two end-member scenarios: one in which the climate is warmed entirely by CO2 (which we refer to as the greenhouse gas (GHG) scenario) and another in which it is warmed entirely by reduced cloud albedo (which we refer to as the low CO2-thin clouds or LCTC scenario) . The two simulations have an almost identical global-mean surface temperature and equator-to-pole temperature difference, but the LCTC scenario has ˜ 11 % greater global-mean precipitation than the GHG scenario. The LCTC scenario also has cooler midlatitude continents and warmer oceans than the GHG scenario and a tropical climate which is significantly more El Niño-like. Extremely high warm-season temperatures in the subtropics are mitigated in the LCTC scenario, while cool-season temperatures are lower at all latitudes. These changes appear large enough to motivate further, more detailed study using other climate models and a more realistic set of modelling assumptions.

  15. A zero-power warming chamber for investigating plant responses to rising temperature

    Directory of Open Access Journals (Sweden)

    K. F. Lewin

    2017-09-01

    Full Text Available Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering warming scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive warming using solar radiation is often the only viable approach for temperature manipulation. However, current passive warming approaches are only able to elevate the mean daily air temperature by  ∼  1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where warming has been markedly greater than the global average and where future warming is projected to be  ∼  2–3 °C by the middle of the century; we have developed an alternative approach to passive warming. Our zero-power warming (ZPW chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for warming and eliminating the risk of overheating. During the thaw season on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the warming achieved by an adjacent passively warmed control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. The approach we describe is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive warming

  16. A zero-power warming chamber for investigating plant responses to rising temperature

    Science.gov (United States)

    Lewin, Keith F.; McMahon, Andrew M.; Ely, Kim S.; Serbin, Shawn P.; Rogers, Alistair

    2017-09-01

    Advances in understanding and model representation of plant and ecosystem responses to rising temperature have typically required temperature manipulation of research plots, particularly when considering warming scenarios that exceed current climate envelopes. In remote or logistically challenging locations, passive warming using solar radiation is often the only viable approach for temperature manipulation. However, current passive warming approaches are only able to elevate the mean daily air temperature by ˜ 1.5 °C. Motivated by our need to understand temperature acclimation in the Arctic, where warming has been markedly greater than the global average and where future warming is projected to be ˜ 2-3 °C by the middle of the century; we have developed an alternative approach to passive warming. Our zero-power warming (ZPW) chamber requires no electrical power for fully autonomous operation. It uses a novel system of internal and external heat exchangers that allow differential actuation of pistons in coupled cylinders to control chamber venting. This enables the ZPW chamber venting to respond to the difference between the external and internal air temperatures, thereby increasing the potential for warming and eliminating the risk of overheating. During the thaw season on the coastal tundra of northern Alaska our ZPW chamber was able to elevate the mean daily air temperature 2.6 °C above ambient, double the warming achieved by an adjacent passively warmed control chamber that lacked our hydraulic system. We describe the construction, evaluation and performance of our ZPW chamber and discuss the impact of potential artefacts associated with the design and its operation on the Arctic tundra. The approach we describe is highly flexible and tunable, enabling customization for use in many different environments where significantly greater temperature manipulation than that possible with existing passive warming approaches is desired.

  17. Seasonal and inter-annual temperature variability in the bottom waters over the Black Sea shelf

    Science.gov (United States)

    Shapiro, G. I.; Wobus, F.; Aleynik, D. L.

    2011-02-01

    Long-term changes in the state of the Bottom Shelf Water (BSW) on the Western shelf of the Black Sea are assessed using analysis of intra- and inter-annual variations of temperature as well as their relations to physical parameters of both shelf and deep-sea waters. First, large data sets of in-situ observations over the 20th century are compiled into high-resolution monthly climatology at different depth levels. Then, the temperature anomalies from the climatic mean are calculated and aggregated into spatial compartments and seasonal bins to reveal temporal evolution of the BSW. For the purpose of this study the BSW is defined as such shelf water body between the seabed and the upper mixed layer (bounded by the σθ = 14.2 isopycnal) which has limited ability to mix vertically with oxygen-rich surface waters during the warm season (May-November) due to the formation of a seasonal pycnocline. The effects of atmospheric processes at the surface on the BSW are hence suppressed as well as the action of the "biological pump". The vertical extent of the near- bottom waters is determined based on energy considerations and the structure of the seasonal pycnocline, whilst the horizontal extent is controlled by the shelf break, where strong along-slope currents hinder exchanges with the deep sea. The BSW is shown to occupy nearly half of the area of the shelf during the summer stratification period. The potential of the BSW to ventilate horizontally during the warm season with the deep-sea waters is assessed using isopycnic analysis of temperature variations. A long-term time series of temperature anomalies in the BSW is constructed from observations during the May-November period for the 2nd half of the 20th century. The results reveal a warm phase in the 1960s/70s, followed by cooling of the BSW during 1980-2001. The transition between the warm and cold periods coincides with a regime shift in the Black Sea ecosystem. While it was confirmed that the memory of winter

  18. Amplified warming projections for high altitude regions of the northern hemisphere mid-latitudes from CMIP5 models

    International Nuclear Information System (INIS)

    Rangwala, Imtiaz; Sinsky, Eric; Miller, James R

    2013-01-01

    We use output from global climate models available from the Coupled Model Intercomparison Project Phase 5 (CMIP5) for three different greenhouse gas emission scenarios to investigate whether the projected warming in mountains by the end of the 21st century is significantly different from that in low elevation regions. To remove the effects of latitudinal variation in warming rates, we focus on seasonal changes in the mid-latitude band of the northern hemisphere between 27.5° N and 40° N, where the two major mountain systems are the Tibetan Plateau/Himalayas in Asia and the Rocky Mountains in the United States. Results from the multi-model ensemble indicate that warming rates in mountains will be enhanced relative to non-mountain regions at the same latitude, particularly during the cold season. The strongest correlations of enhanced warming with elevation are obtained for the daily minimum temperature during winter, with the largest increases found for the Tibetan Plateau/Himalayas. The model projections indicate that this occurs, in part, because of proportionally greater increases in downward longwave radiation at higher elevations in response to increases in water vapor. The mechanisms for enhanced increases in winter and spring maximum temperatures in the Rockies appear to be influenced more by increases in surface absorption of solar radiation owing to a reduced snow cover. Furthermore, the amplification of warming with elevation is greater for a higher greenhouse gas emission scenario. (letter)

  19. Indo-Pacific sea surface temperature influences on failed consecutive rainy seasons over eastern Africa

    Science.gov (United States)

    Hoell, Andrew; Funk, Christopher C.

    2014-01-01

    Rainfall over eastern Africa (10°S–10°N; 35°E–50°E) is bimodal, with seasonal maxima during the "long rains" of March–April–May (MAM) and the "short rains" of October–November–December (OND). Below average precipitation during consecutive long and short rains seasons over eastern Africa can have devastating long-term impacts on water availability and agriculture. Here, we examine the forcing of drought during consecutive long and short rains seasons over eastern Africa by Indo-Pacific sea surface temperatures (SSTs). The forcing of eastern Africa precipitation and circulation by SSTs is tested using ten ensemble simulations of a global weather forecast model forced by 1950–2010 observed global SSTs. Since the 1980s, Indo-Pacific SSTs have forced more frequent droughts spanning consecutive long and short rains seasons over eastern Africa. The increased frequency of dry conditions is linked to warming SSTs over the Indo-west Pacific and to a lesser degree to Pacific Decadal Variability. During MAM, long-term warming of tropical west Pacific SSTs from 1950–2010 has forced statistically significant precipitation reductions over eastern Africa. The warming west Pacific SSTs have forced changes in the regional lower tropospheric circulation by weakening the Somali Jet, which has reduced moisture and rainfall over the Horn of Africa. During OND, reductions in precipitation over recent decades are oftentimes overshadowed by strong year-to-year precipitation variability forced by the Indian Ocean Dipole and the El Niño–Southern Oscillation.

  20. Soil warming increased whole-tree water use of Pinus cembra at the treeline in the Central Tyrolean Alps.

    Science.gov (United States)

    Wieser, Gerhard; Grams, Thorsten E E; Matyssek, Rainer; Oberhuber, Walter; Gruber, Andreas

    2015-03-01

    This study quantified the effect of soil warming on sap flow density (Qs) of Pinus cembra L. at the treeline in the Central Tyrolean Alps. To enhance soil temperature we installed a transparent roof construction above the forest floor around six trees. Six other trees served as controls in the absence of any manipulation. Roofing enhanced growing season mean soil temperature by 1.6, 1.3 and 1.0 °C at 5, 10 and 20 cm soil depth, respectively, while soil water availability was not affected. Sap flow density (using Granier-type thermal dissipation probes) and environmental parameters were monitored throughout three growing seasons. During the first year of treatment, no warming effect was detected on Qs. However, soil warming caused Qs to increase significantly by 11 and 19% above levels in control trees during the second and third year, respectively. This effect appeared to result from warming-induced root production, a reduction in viscosity and perhaps an increase also in root hydraulic conductivity. Hardly affected were leaf-level net CO2 uptake rate and conductance for water vapour, so that water-use efficiency stayed unchanged as confirmed by needle δ(13)C analysis. We conclude that tree water loss will increase with soil warming, which may alter the water balance within the treeline ecotone of the Central Austrian Alps in a future warming environment. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Reducing the uncertainty of parameters controlling seasonal carbon and water fluxes in Chinese forests and its implication for simulated climate sensitivities

    Science.gov (United States)

    Li, Yue; Yang, Hui; Wang, Tao; MacBean, Natasha; Bacour, Cédric; Ciais, Philippe; Zhang, Yiping; Zhou, Guangsheng; Piao, Shilong

    2017-08-01

    Reducing parameter uncertainty of process-based terrestrial ecosystem models (TEMs) is one of the primary targets for accurately estimating carbon budgets and predicting ecosystem responses to climate change. However, parameters in TEMs are rarely constrained by observations from Chinese forest ecosystems, which are important carbon sink over the northern hemispheric land. In this study, eddy covariance data from six forest sites in China are used to optimize parameters of the ORganizing Carbon and Hydrology In Dynamics EcosystEms TEM. The model-data assimilation through parameter optimization largely reduces the prior model errors and improves the simulated seasonal cycle and summer diurnal cycle of net ecosystem exchange, latent heat fluxes, and gross primary production and ecosystem respiration. Climate change experiments based on the optimized model are deployed to indicate that forest net primary production (NPP) is suppressed in response to warming in the southern China but stimulated in the northeastern China. Altered precipitation has an asymmetric impact on forest NPP at sites in water-limited regions, with the optimization-induced reduction in response of NPP to precipitation decline being as large as 61% at a deciduous broadleaf forest site. We find that seasonal optimization alters forest carbon cycle responses to environmental change, with the parameter optimization consistently reducing the simulated positive response of heterotrophic respiration to warming. Evaluations from independent observations suggest that improving model structure still matters most for long-term carbon stock and its changes, in particular, nutrient- and age-related changes of photosynthetic rates, carbon allocation, and tree mortality.

  2. Widespread Amazon forest tree mortality from a single cross-basin squall line event

    Science.gov (United States)

    Negrón-Juárez, Robinson I.; Chambers, Jeffrey Q.; Guimaraes, Giuliano; Zeng, Hongcheng; Raupp, Carlos F. M.; Marra, Daniel M.; Ribeiro, Gabriel H. P. M.; Saatchi, Sassan S.; Nelson, Bruce W.; Higuchi, Niro

    2010-08-01

    Climate change is expected to increase the intensity of extreme precipitation events in Amazonia that in turn might produce more forest blowdowns associated with convective storms. Yet quantitative tree mortality associated with convective storms has never been reported across Amazonia, representing an important additional source of carbon to the atmosphere. Here we demonstrate that a single squall line (aligned cluster of convective storm cells) propagating across Amazonia in January, 2005, caused widespread forest tree mortality and may have contributed to the elevated mortality observed that year. Forest plot data demonstrated that the same year represented the second highest mortality rate over a 15-year annual monitoring interval. Over the Manaus region, disturbed forest patches generated by the squall followed a power-law distribution (scaling exponent α = 1.48) and produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. Basin-wide, potential tree mortality from this one event was estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. Storm intensity is expected to increase with a warming climate, which would result in additional tree mortality and carbon release to the atmosphere, with the potential to further warm the climate system.

  3. Recent increased warming of the Alaskan marine Arctic due to midlatitude linkages

    Science.gov (United States)

    Overland, James E.; Wang, Muyin; Ballinger, Thomas J.

    2018-01-01

    Alaskan Arctic waters have participated in hemispheric-wide Arctic warming over the last two decades at over two times the rate of global warming. During 2008-13, this relative warming occurred only north of the Bering Strait and the atmospheric Arctic front that forms a north-south thermal barrier. This front separates the southeastern Bering Sea temperatures from Arctic air masses. Model projections show that future temperatures in the Chukchi and Beaufort seas continue to warm at a rate greater than the global rate, reaching a change of +4°C by 2040 relative to the 1981-2010 mean. Offshore at 74°N, climate models project the open water duration season to increase from a current average of three months to five months by 2040. These rates are occasionally enhanced by midlatitude connections. Beginning in August 2014, additional Arctic warming was initiated due to increased SST anomalies in the North Pacific and associated shifts to southerly winds over Alaska, especially in winter 2015-16. While global warming and equatorial teleconnections are implicated in North Pacific SSTs, the ending of the 2014-16 North Pacific warm event demonstrates the importance of internal, chaotic atmospheric natural variability on weather conditions in any given year. Impacts from global warming on Alaskan Arctic temperature increases and sea-ice and snow loss, with occasional North Pacific support, are projected to continue to propagate through the marine ecosystem in the foreseeable future. The ecological and societal consequences of such changes show a radical departure from the current Arctic environment.

  4. Acclimation and soil moisture constrain sugar maple root respiration in experimentally warmed soil.

    Science.gov (United States)

    Jarvi, Mickey P; Burton, Andrew J

    2013-09-01

    The response of root respiration to warmer soil can affect ecosystem carbon (C) allocation and the strength of positive feedbacks between climatic warming and soil CO2 efflux. This study sought to determine whether fine-root (maple (Acer saccharum Marsh.)-dominated northern hardwood forest would adjust to experimentally warmed soil, reducing C return to the atmosphere at the ecosystem scale to levels lower than that would be expected using an exponential temperature response function. Infrared heating lamps were used to warm the soil (+4 to +5 °C) in a mature sugar maple forest in a fully factorial design, including water additions used to offset the effects of warming-induced dry soil. Fine-root-specific respiration rates, root biomass, root nitrogen (N) concentration, soil temperature and soil moisture were measured from 2009 to 2011, with experimental treatments conducted from late 2010 to 2011. Partial acclimation of fine-root respiration to soil warming occurred, with soil moisture deficit further constraining specific respiration rates in heated plots. Fine-root biomass and N concentration remained unchanged. Over the 2011 growing season, ecosystem root respiration was not significantly greater in warmed soil. This result would not be predicted by models that allow respiration to increase exponentially with temperature and do not directly reduce root respiration in drier soil.

  5. Nephrolithiasis, stone composition, meteorology, and seasons in Malta: Is there any connection?

    Science.gov (United States)

    Buttigieg, Jesmar; Attard, Stephanie; Carachi, Alexander; Galea, Ruth; Fava, Stephen

    2016-01-01

    The effect of seasons and meteorology on the incidence of nephrolithiasis has been studied in various regions around the globe, but seldom in the Mediterranean. This retrospective analysis aims at investigating these putative effects in the Maltese Islands, whose climate is typically Mediterranean, followed by a systematic review of the literature. Submission rate and chemical composition of all kidney stones after spontaneous passage or surgical removal between January 2009 and December 2011 were analyzed according to seasons and corresponding meteorology. A total of 389 stones were analyzed. A higher stone submission rate was observed in summer compared to winter (31.6% vs. 20.8%, P = 0.0008) and in the warm period compared to the cold period (57.1% vs. 42.9%, P = 0.0001). Significant correlation was established between the monthly number of stones and mean monthly maximum temperature (r = 0.50, P = 0.002), mean monthly temperature (r = 0.49, P = 0.003) and mean monthly Humidex (r = 0.49, P = 0.007). Humidex was found to be an independent predictor for stone submission (β = 0.49, P = 0.007). The majority of stones contained calcium (83.3%), combined with oxalate (77.6%), phosphate (14.7%), and carbonate (2.8%). Some stones (11.8%) contained a mixture of >1 negatively charged molecules. Urate (11.6%), cysteine (4.6%), and ammonium-magnesium-phosphate (0.5%) constituted the rest. There was no association between chemical composition and seasons. Literature review included 25 articles. Higher ambient temperature and warm seasons were the most commonly encountered risk factors for both presentation and etiology of nephrolithiasis. A significant positive correlation was noted between ambient temperature and stone submission rate, which was significantly higher during the warm months in Malta.

  6. In a warmer Arctic, mosquitoes avoid increased mortality from predators by growing faster.

    Science.gov (United States)

    Culler, Lauren E; Ayres, Matthew P; Virginia, Ross A

    2015-09-22

    Climate change is altering environmental temperature, a factor that influences ectothermic organisms by controlling rates of physiological processes. Demographic effects of warming, however, are determined by the expression of these physiological effects through predator-prey and other species interactions. Using field observations and controlled experiments, we measured how increasing temperatures in the Arctic affected development rates and mortality rates (from predation) of immature Arctic mosquitoes in western Greenland. We then developed and parametrized a demographic model to evaluate how temperature affects survival of mosquitoes from the immature to the adult stage. Our studies showed that warming increased development rate of immature mosquitoes (Q10 = 2.8) but also increased daily mortality from increased predation rates by a dytiscid beetle (Q10 = 1.2-1.5). Despite increased daily mortality, the model indicated that faster development and fewer days exposed to predators resulted in an increased probability of mosquito survival to the adult stage. Warming also advanced mosquito phenology, bringing mosquitoes into phenological synchrony with caribou. Increases in biting pests will have negative consequences for caribou and their role as a subsistence resource for local communities. Generalizable frameworks that account for multiple effects of temperature are needed to understand how climate change impacts coupled human-natural systems. © 2015 The Author(s).

  7. Seasonal variation of the protozooplanktonic community in a tropical oligotrophic environment (Ilha Solteira reservoir, Brazil).

    Science.gov (United States)

    Mansano, A S; Hisatugo, K F; Leite, M A; Luzia, A P; Regali-Seleghim, M H

    2013-05-01

    The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae) was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold). The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L-1), while the lowest was in the dry/cold (2016.0 ind L-1). Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea), predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI). The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI) and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species).

  8. Late Cretaceous seasonal ocean variability from the Arctic.

    Science.gov (United States)

    Davies, Andrew; Kemp, Alan E S; Pike, Jennifer

    2009-07-09

    The modern Arctic Ocean is regarded as a barometer of global change and amplifier of global warming and therefore records of past Arctic change are critical for palaeoclimate reconstruction. Little is known of the state of the Arctic Ocean in the greenhouse period of the Late Cretaceous epoch (65-99 million years ago), yet records from such times may yield important clues to Arctic Ocean behaviour in near-future warmer climates. Here we present a seasonally resolved Cretaceous sedimentary record from the Alpha ridge of the Arctic Ocean. This palaeo-sediment trap provides new insight into the workings of the Cretaceous marine biological carbon pump. Seasonal primary production was dominated by diatom algae but was not related to upwelling as was previously hypothesized. Rather, production occurred within a stratified water column, involving specially adapted species in blooms resembling those of the modern North Pacific subtropical gyre, or those indicated for the Mediterranean sapropels. With increased CO(2) levels and warming currently driving increased stratification in the global ocean, this style of production that is adapted to stratification may become more widespread. Our evidence for seasonal diatom production and flux testify to an ice-free summer, but thin accumulations of terrigenous sediment within the diatom ooze are consistent with the presence of intermittent sea ice in the winter, supporting a wide body of evidence for low temperatures in the Late Cretaceous Arctic Ocean, rather than recent suggestions of a 15 degrees C mean annual temperature at this time.

  9. Strong delayed interactive effects of metal exposure and warming

    DEFF Research Database (Denmark)

    Debecker, Sara; Dinh, Khuong Van; Stoks, Robby

    2017-01-01

    ’ ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and lowlatitude populations. By integrating these mechanisms...... into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis...... was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies...

  10. A model study of the seasonality of sea surface temperature and circulation in the Atlantic North-Eastern Tropical Upwelling System.

    Directory of Open Access Journals (Sweden)

    Saliou eFaye

    2015-09-01

    Full Text Available The climatological seasonal cycle of the sea surface temperature (SST in the north-eastern tropical Atlantic (7-25°N, 26-12°W is studied using a mixed layer heat budget in a regional ocean general circulation model. The region, which experiences one of the larger SST cycle in the tropics, forms the main part of the Guinea Gyre. It is characterized by a seasonally varying open ocean and coastal upwelling system, driven by the movements of the intertropical convergence zone (ITCZ. The model annual mean heat budget has two regimes schematically. South of roughly 12°N, advection of equatorial waters, mostly warm, and warming by vertical mixing, is balanced by net air-sea flux. In the rest of the domain, a cooling by vertical mixing, reinforced by advection at the coast, is balanced by the air-sea fluxes. Regarding the seasonal cycle, within a narrow continental band, in zonal mean, the SST early decrease (from September, depending on latitude, until December is driven by upwelling dynamics off Senegal and Mauritania (15°-20°N, and instead by air-sea fluxes north and south of these latitudes. Paradoxically, the later peaks of upwelling intensity (from March to July, with increasing latitude essentially damp the warming phase, driven by air-sea fluxes. The open ocean cycle to the west, is entirely driven by the seasonal net air-sea fluxes. The oceanic processes significantly oppose it, but for winter north of ~18°N. Vertical mixing in summer-autumn tends to cool (warm the surface north (south of the ITCZ, and advective cooling or warming by the geostrophic Guinea Gyre currents and the Ekman drift. This analysis supports previous findings on the importance of air-sea fluxes offshore. It mainly offers quantitative elements on the modulation of the SST seasonal cycle by the ocean circulation, and particularly by the upwelling dynamics.Keywords: SST, upwelling, circulation, heat budget, observations, modeling

  11. Growth and phenology of three dwarf shrub species in a six-year soil warming experiment at the alpine treeline.

    Science.gov (United States)

    Anadon-Rosell, Alba; Rixen, Christian; Cherubini, Paolo; Wipf, Sonja; Hagedorn, Frank; Dawes, Melissa A

    2014-01-01

    Global warming can have substantial impacts on the phenological and growth patterns of alpine and Arctic species, resulting in shifts in plant community composition and ecosystem dynamics. We evaluated the effects of a six-year experimental soil warming treatment (+4°C, 2007-2012) on the phenology and growth of three co-dominant dwarf shrub species growing in the understory of Larix decidua and Pinus uncinata at treeline in the Swiss Alps. We monitored vegetative and reproductive phenology of Vaccinium myrtillus, Vaccinium gaultherioides and Empetrum hermaphroditum throughout the early growing season of 2012 and, following a major harvest at peak season, we measured the biomass of above-ground ramet fractions. For all six years of soil warming we measured annual shoot growth of the three species and analyzed ramet age and xylem ring width of V. myrtillus. Our results show that phenology of the three species was more influenced by snowmelt timing, and also by plot tree species (Larix or Pinus) in the case of V. myrtillus, than by soil warming. However, the warming treatment led to increased V. myrtillus total above-ground ramet biomass (+36% in 2012), especially new shoot biomass (+63% in 2012), as well as increased new shoot increment length and xylem ring width (+22% and +41%, respectively; average for 2007-2012). These results indicate enhanced overall growth of V. myrtillus under soil warming that was sustained over six years and was not caused by an extended growing period in early summer. In contrast, E. hermaphroditum only showed a positive shoot growth response to warming in 2011 (+21%), and V. gaultherioides showed no significant growth response. Our results indicate that V. myrtillus might have a competitive advantage over the less responsive co-occurring dwarf shrub species under future global warming.

  12. Growth and phenology of three dwarf shrub species in a six-year soil warming experiment at the alpine treeline.

    Directory of Open Access Journals (Sweden)

    Alba Anadon-Rosell

    Full Text Available Global warming can have substantial impacts on the phenological and growth patterns of alpine and Arctic species, resulting in shifts in plant community composition and ecosystem dynamics. We evaluated the effects of a six-year experimental soil warming treatment (+4°C, 2007-2012 on the phenology and growth of three co-dominant dwarf shrub species growing in the understory of Larix decidua and Pinus uncinata at treeline in the Swiss Alps. We monitored vegetative and reproductive phenology of Vaccinium myrtillus, Vaccinium gaultherioides and Empetrum hermaphroditum throughout the early growing season of 2012 and, following a major harvest at peak season, we measured the biomass of above-ground ramet fractions. For all six years of soil warming we measured annual shoot growth of the three species and analyzed ramet age and xylem ring width of V. myrtillus. Our results show that phenology of the three species was more influenced by snowmelt timing, and also by plot tree species (Larix or Pinus in the case of V. myrtillus, than by soil warming. However, the warming treatment led to increased V. myrtillus total above-ground ramet biomass (+36% in 2012, especially new shoot biomass (+63% in 2012, as well as increased new shoot increment length and xylem ring width (+22% and +41%, respectively; average for 2007-2012. These results indicate enhanced overall growth of V. myrtillus under soil warming that was sustained over six years and was not caused by an extended growing period in early summer. In contrast, E. hermaphroditum only showed a positive shoot growth response to warming in 2011 (+21%, and V. gaultherioides showed no significant growth response. Our results indicate that V. myrtillus might have a competitive advantage over the less responsive co-occurring dwarf shrub species under future global warming.

  13. Trends in land surface phenology and atmospheric CO2 seasonality in the Northern Hemisphere terrestrial ecosystems

    Science.gov (United States)

    Gonsamo, A.; Chen, J. M.

    2017-12-01

    Northern terrestrial ecosystems have shown global warming-induced advances in start, delays in end, and thus increased lengths of growing season and gross photosynthesis in recent decades. The tradeoffs between seasonal dynamics of two opposing fluxes, CO2 uptake through photosynthesis and release through respiration, determine the influence of the terrestrial ecosystems on the atmospheric CO2 concentration and 13C/12C isotope ratio seasonality. Atmospheric CO2 and 13C/12C seasonality is controlled by vegetation phenology, but is not identical because growth will typically commence some time before and terminate some time after the net carbon exchange changes sign in spring and autumn, respectively. Here, we use 34-year satellite normalized difference vegetation index (NDVI) observations to determine how changes in vegetation productivity and phenology affect both the atmospheric CO2 and 13C/12C seasonality. Differences and similarities in recent trends of CO2 and 13C/12C seasonality and vegetation phenology will be discussed. Furthermore, we use the NDVI observations, and atmospheric CO2 and 13C/12C data to show the trends and variability of the timing of peak season plant activity. Preliminary results show that the peak season plant activity of the Northern Hemisphere extra-tropical terrestrial ecosystems is shifting towards spring, largely in response to the warming-induced advance of the start of growing season. Besides, the spring-ward shift of the peak plant activity is contributing the most to the increasing peak season productivity. In other words, earlier start of growing season is highly linked to earlier arrival of peak of season and higher NDVI. Changes in the timing of peak season plant activity are expected to disrupt the synchrony of biotic interaction and exert strong biophysical feedbacks on climate by modifying the surface albedo and energy budget.

  14. Mortality risk factors for calves entering a multi-location white veal farm in Ontario, Canada.

    Science.gov (United States)

    Winder, Charlotte B; Kelton, David F; Duffield, Todd F

    2016-12-01

    Mortality in preweaned dairy-breed calves, whether they are replacement dairy heifers, veal animals, or dairy beef animals, represents both a welfare issue and a source of economic loss for the industries involved. Studies describing morbidity and mortality in veal calves have illustrated different management practices and requirements in terms of housing and nutrition around the world. Studies examining the rearing of replacement dairy heifers have shown that rates of morbidity and mortality can vary dramatically between farms, perhaps reflecting differences in management strategies. It has been over 2 decades since morbidity and mortality in veal calves in Ontario were described. The objective of this retrospective population cohort study was to describe mortality and determine whether on-arrival information could be used to predict mortality risk. Predictors could be used to both better classify and group calves on arrival and provide feedback to suppliers about the characteristics of the highest- and lowest-risk calves. We collected data from 10,910 calves entering 7 barns of a single white veal farm, all in Ontario, from January 1 to December 31, 2014. Calves were followed until death or marketing (typically 140 to 150 d). We developed logistic regression models to determine the effects of weight on arrival, season of arrival, supplier, sex, barn, and purchase price on the risk of total mortality, early mortality (0-21d after arrival), and late mortality (>21d after arrival). We identified significant associations between season, barn, supplier, weight, and total mortality risk, with lighter-weight calves arriving in winter being at increased risk. Early mortality was significantly associated with weight, season, barn, and supplier, and tended to be associated with standardized price; lighter-weight calves arriving in winter at lower prices were at increased risk. Late mortality was significantly associated with season of arrival, barn, and supplier. On

  15. Biochemical impacts of Hg in Mytilus galloprovincialis under present and predicted warming scenarios.

    Science.gov (United States)

    Coppola, Francesca; Almeida, Ângela; Henriques, Bruno; Soares, Amadeu M V M; Figueira, Etelvina; Pereira, Eduarda; Freitas, Rosa

    2017-12-01

    The interest in the consequences of climate change on the physiological and biochemical functioning of marine organisms is increasing, but the indirect and interactive effects resulting from warming on bioconcentration and responsiveness to pollutants are still poorly explored, particularly in terms of cellular responses. The present study investigated the impacts of Hg in Mytilus galloprovincialis under control (17°C) and warming (21°C) conditions, assessing mussels Hg bioconcentration capacity, metabolic and oxidative status after 14 and 28days of exposure. Results obtained showed greater impacts in mussels exposed for 28days in comparison to 14days of exposure. Furthermore, our findings revealed that the increase in temperature from 17 to 21°C reduced the bioconcentration of Hg by M. galloprovincialis, which may explain higher mortality rates at 17°C in comparison to 21°C. Lower Hg concentration at 21°C in mussels tissue may result from valves closure for longer periods, identified by reduced energy reserves consumption at higher temperature, which in turn might also contributed to higher oxidative stress in organisms exposed to this condition. The highest LPO levels observed in mussels exposed to higher temperatures alone indicate that warming conditions will greatly affect M. galloprovincialis. Furthermore, the present study showed that the impacts induced by the combination of Hg and warming were similar to the ones caused by increased temperature acting alone, mainly due to increased antioxidant defenses in organisms under combined effects of Hg and warming, suggesting that warming was the factor that mostly contributed to oxidative stress in mussels. Although higher mortality was observed in individuals exposed to 17°C and Hg compared to organisms exposed to Hg at 21°C, the oxidative stress induced at higher temperature may generate negative consequences on mussels reproductive and feeding capacity, growth and, consequently, on population

  16. Response of snow-dependent hydrologic extremes to continued global warming

    Energy Technology Data Exchange (ETDEWEB)

    Diffenbaugh, Noah [Stanford University; Scherer, Martin [Stanford University; Ashfaq, Moetasim [ORNL

    2012-01-01

    Snow accumulation is critical for water availability in the Northern Hemisphere1,2, raising concern that global warming could have important impacts on natural and human systems in snow-dependent regions1,3. Although regional hydrologic changes have been observed (for example, refs 1,3 5), the time of emergence of extreme changes in snow accumulation and melt remains a key unknown for assessing climate- change impacts3,6,7. We find that the CMIP5 global climate model ensemble exhibits an imminent shift towards low snow years in the Northern Hemisphere, with areas of western North America, northeastern Europe and the Greater Himalaya showing the strongest emergence during the near- termdecadesandat2 Cglobalwarming.Theoccurrenceof extremely low snow years becomes widespread by the late twenty-first century, as do the occurrences of extremely high early-season snowmelt and runoff (implying increasing flood risk), and extremely low late-season snowmelt and runoff (implying increasing water stress). Our results suggest that many snow-dependent regions of the Northern Hemisphere are likely to experience increasing stress from low snow years within the next three decades, and from extreme changes in snow-dominated water resources if global warming exceeds 2 C above the pre-industrial baseline.

  17. Implications of global warming for the climate of African rainforests.

    Science.gov (United States)

    James, Rachel; Washington, Richard; Rowell, David P

    2013-01-01

    African rainforests are likely to be vulnerable to changes in temperature and precipitation, yet there has been relatively little research to suggest how the regional climate might respond to global warming. This study presents projections of temperature and precipitation indices of relevance to African rainforests, using global climate model experiments to identify local change as a function of global temperature increase. A multi-model ensemble and two perturbed physics ensembles are used, one with over 100 members. In the east of the Congo Basin, most models (92%) show a wet signal, whereas in west equatorial Africa, the majority (73%) project an increase in dry season water deficits. This drying is amplified as global temperature increases, and in over half of coupled models by greater than 3% per °C of global warming. Analysis of atmospheric dynamics in a subset of models suggests that this could be partly because of a rearrangement of zonal circulation, with enhanced convection in the Indian Ocean and anomalous subsidence over west equatorial Africa, the Atlantic Ocean and, in some seasons, the Amazon Basin. Further research to assess the plausibility of this and other mechanisms is important, given the potential implications of drying in these rainforest regions.

  18. Intraseasonal variation in survival and probable causes of mortality in greater sage-grouse Centrocercus urophasianus

    Science.gov (United States)

    Blomberg, Erik J.; Gibson, Daniel; Sedinger, James S.; Casazza, Michael L.; Coates, Peter S.

    2013-01-01

    The mortality process is a key component of avian population dynamics, and understanding factors that affect mortality is central to grouse conservation. Populations of greater sage-grouse Centrocercus urophasianus have declined across their range in western North America. We studied cause-specific mortality of radio-marked sage-grouse in Eureka County, Nevada, USA, during two seasons, nesting (2008-2012) and fall (2008-2010), when survival was known to be lower compared to other times of the year. We used known-fate and cumulative incidence function models to estimate weekly survival rates and cumulative risk of cause-specific mortalities, respectively. These methods allowed us to account for temporal variation in sample size and staggered entry of marked individuals into the sample to obtain robust estimates of survival and cause-specific mortality. We monitored 376 individual sage-grouse during the course of our study, and investigated 87 deaths. Predation was the major source of mortality, and accounted for 90% of all mortalities during our study. During the nesting season (1 April - 31 May), the cumulative risk of predation by raptors (0.10; 95% CI: 0.05-0.16) and mammals (0.08; 95% CI: 0.03-013) was relatively equal. In the fall (15 August - 31 October), the cumulative risk of mammal predation was greater (M(mam) = 0.12; 95% CI: 0.04-0.19) than either predation by raptors (M(rap) = 0.05; 95% CI: 0.00-0.10) or hunting harvest (M(hunt) = 0.02; 95% CI: 0.0-0.06). During both seasons, we observed relatively few additional sources of mortality (e.g. collision) and observed no evidence of disease-related mortality (e.g. West Nile Virus). In general, we found little evidence for intraseasonal temporal variation in survival, suggesting that the nesting and fall seasons represent biologically meaningful time intervals with respect to sage-grouse survival.

  19. Exceptional Air Mass Transport and Dynamical Drivers of an Extreme Wintertime Arctic Warm Event

    Science.gov (United States)

    Binder, Hanin; Boettcher, Maxi; Grams, Christian M.; Joos, Hanna; Pfahl, Stephan; Wernli, Heini

    2017-12-01

    At the turn of the years 2015/2016, maximum surface temperature in the Arctic reached record-high values, exceeding the melting point, which led to a strong reduction of the Arctic sea ice extent in the middle of the cold season. Here we show, using a Lagrangian method, that a combination of very different airstreams contributed to this event: (i) warm low-level air of subtropical origin, (ii) initially cold low-level air of polar origin heated by surface fluxes, and (iii) strongly descending air heated by adiabatic compression. The poleward transport of these warm airstreams occurred along an intense low-level jet between a series of cyclones and a quasi-stationary anticyclone. The complex 3-D configuration that enabled this transport was facilitated by continuous warm conveyor belt ascent into the upper part of the anticyclone. This study emphasizes the combined role of multiple transport processes and transient synoptic-scale dynamics for establishing an extreme Arctic warm event.

  20. Indonesian vegetation response to changes in rainfall seasonality over the past 25,000 years

    Science.gov (United States)

    Dubois, Nathalie; Oppo, Delia W.; Galy, Valier V.; Mohtadi, Mahyar; van der Kaars, Sander; Tierney, Jessica E.; Rosenthal, Yair; Eglinton, Timothy I.; Lückge, Andreas; Linsley, Braddock K.

    2014-07-01

    The hydrologic response to climate forcing in the Indo-Pacific warm pool region has varied spatially over the past 25,000 years. For example, drier conditions are inferred on Java and Borneo for the period following the end of the Last Glacial Maximum, whereas wetter conditions are reconstructed for northwest Australia. The response of vegetation to these past rainfall variations is poorly constrained. Using a suite of 30 surface marine sediment samples from throughout the Indo-Pacific warm pool, we demonstrate that today the stable isotopic composition of vascular plant fatty acids (δ13CFA) reflects the regional vegetation composition. This in turn is controlled by the seasonality of rainfall consistent with dry season water stress. Applying this proxy in a sediment core from offshore northeast Borneo, we show broadly similar vegetation cover during the Last Glacial Maximum and the Holocene, suggesting that, despite generally drier glacial conditions, there was no pronounced dry season. In contrast, δ13CFA and pollen data from a core off the coast of Sumba indicate an expansion of C4 herbs during the most recent glaciation, implying enhanced aridity and water stress during the dry season. Holocene vegetation trends are also consistent with a response to dry season water stress. We therefore conclude that vegetation in tropical monsoon regions is susceptible to increases in water stress arising from an enhanced seasonality of rainfall, as has occurred in past decades.

  1. Interannual Similarity in the Martian Atmosphere During the Dust Storm Season

    Science.gov (United States)

    Kass, D. M.; Kleinboehl, A.; McCleese, D. J.; Schofield, J. T.; Smith, M. D.

    2016-01-01

    We find that during the dusty season on Mars (southern spring and summer) of years without a global dust storm there are three large regional-scale dust storms. The storms are labeled A, B, and C in seasonal order. This classification is based on examining the zonal mean 50 Pa (approximately 25 km) daytime temperature retrievals from TES/MGS and MCS/MRO over 6 Mars Years. Regional-scale storms are defined as events where the temperature exceeds 200 K. Examining the MCS dust field at 50 Pa indicates that warming in the Southern Hemisphere is dominated by direct heating, while northern high latitude warming is a dynamical response. A storms are springtime planet encircling Southern Hemisphere events. B storms are southern polar events that begin near perihelion and last through the solstice. C storms are southern summertime events starting well after the end of the B storm. C storms show the most interannual variability.

  2. A phenological timetable of oak growth under experimental drought and air warming.

    Directory of Open Access Journals (Sweden)

    Thomas M Kuster

    Full Text Available Climate change is expected to increase temperature and decrease summer precipitation in Central Europe. Little is known about how warming and drought will affect phenological patterns of oaks, which are considered to possess excellent adaptability to these climatic changes. Here, we investigated bud burst and intra-annual shoot growth of Quercus robur, Q. petraea and Q. pubescens grown on two different forest soils and exposed to air warming and drought. Phenological development was assessed over the course of three growing seasons. Warming advanced bud burst by 1-3 days °C⁻¹ and led to an earlier start of intra-annual shoot growth. Despite this phenological shift, total time span of annual growth and shoot biomass were not affected. Drought changed the frequency and intensity of intra-annual shoot growth and advanced bud burst in the subsequent spring of a severe summer drought by 1-2 days. After re-wetting, shoot growth recovered within a few days, demonstrating the superior drought tolerance of this tree genus. Our findings show that phenological patterns of oaks are modified by warming and drought but also suggest that ontogenetic factors and/or limitations of water and nutrients counteract warming effects on the biomass and the entire span of annual shoot growth.

  3. Linking carbon and water limitations to drought-induced mortality of Pinus flexilis seedlings

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J.; Kueppers, Lara M.; Domec, Jean-Christophe; Mitton, Jeffry

    2015-01-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below −5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  4. Linking carbon and water relations to drought-induced mortality in Pinus flexilis seedlings.

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J; Kueppers, Lara M; Domec, Jean-Christophe; Mitton, Jeffry

    2015-07-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below -5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations. © The Author 2015. Published by Oxford University Press. All rights reserved

  5. Widespread increase of tree mortality rates in the Western United States

    Science.gov (United States)

    van Mantgem, P.J.; Stephenson, N.L.; Byrne, J.C.; Daniels, L.D.; Franklin, J.F.; Fule, P.Z.; Harmon, M.E.; Larson, A.J.; Smith, Joseph M.; Taylor, A.H.; Veblen, T.T.

    2009-01-01

    Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.

  6. Mortality attributable to pandemic influenza A (H1N1) 2009 in San Luis Potosí, Mexico

    Science.gov (United States)

    Comas‐García, Andreu; García‐Sepúlveda, Christian A.; Méndez‐de Lira, José J.; Aranda‐Romo, Saray; Hernández‐Salinas, Alba E.; Noyola, Daniel E.

    2010-01-01

    Please cite this paper as: Comas‐García et al. (2011) Mortality attributable to pandemic influenza A (H1N1) 2009 in San Luis Potosí, Mexico. Influenza and Other Respiratory Viruses 5(2), 76–82. Background  Acute respiratory infections are a leading cause of morbidity and mortality worldwide. Starting in 2009, pandemic influenza A(H1N1) 2009 virus has become one of the leading respiratory pathogens worldwide. However, the overall impact of this virus as a cause of mortality has not been clearly defined. Objectives  To determine the impact of pandemic influenza A(H1N1) 2009 on mortality in a Mexican population. Methods  We assessed the impact of pandemic influenza virus on mortality during the first and second outbreaks in San Luis Potosí, Mexico, and compared it to mortality associated with seasonal influenza and respiratory syncytial virus (RSV) during the previous winter seasons. Results  We estimated that, on average, 8·1% of all deaths that occurred during the 2003–2009 seasons were attributable to influenza and RSV. During the first pandemic influenza A(H1N1) 2009 outbreak, there was an increase in mortality in persons 5–59 years of age, but not during the second outbreak (Fall of 2009). Overall, pandemic influenza A (H1N1) 2009 outbreaks had similar effects on mortality to those associated with seasonal influenza virus epidemics. Conclusions  The impact of influenza A(H1N1) 2009 virus on mortality during the first year of the pandemic was similar to that observed for seasonal influenza. The establishment of real‐time surveillance systems capable of integrating virological, morbidity, and mortality data may result in the timely identification of outbreaks so as to allow for the institution of appropriate control measures to reduce the impact of emerging pathogens on the population. PMID:21306570

  7. Atmospheric circulation and hydroclimate impacts of alternative warming scenarios for the Eocene

    Directory of Open Access Journals (Sweden)

    H. Carlson

    2017-08-01

    Full Text Available Recent work in modelling the warm climates of the early Eocene shows that it is possible to obtain a reasonable global match between model surface temperature and proxy reconstructions, but only by using extremely high atmospheric CO2 concentrations or more modest CO2 levels complemented by a reduction in global cloud albedo. Understanding the mix of radiative forcing that gave rise to Eocene warmth has important implications for constraining Earth's climate sensitivity, but progress in this direction is hampered by the lack of direct proxy constraints on cloud properties. Here, we explore the potential for distinguishing among different radiative forcing scenarios via their impact on regional climate changes. We do this by comparing climate model simulations of two end-member scenarios: one in which the climate is warmed entirely by CO2 (which we refer to as the greenhouse gas (GHG scenario and another in which it is warmed entirely by reduced cloud albedo (which we refer to as the low CO2–thin clouds or LCTC scenario . The two simulations have an almost identical global-mean surface temperature and equator-to-pole temperature difference, but the LCTC scenario has  ∼  11 % greater global-mean precipitation than the GHG scenario. The LCTC scenario also has cooler midlatitude continents and warmer oceans than the GHG scenario and a tropical climate which is significantly more El Niño-like. Extremely high warm-season temperatures in the subtropics are mitigated in the LCTC scenario, while cool-season temperatures are lower at all latitudes. These changes appear large enough to motivate further, more detailed study using other climate models and a more realistic set of modelling assumptions.

  8. Tree mortality predicted from drought-induced vascular damage

    Science.gov (United States)

    Anderegg, William R.L.; Flint, Alan L.; Huang, Cho-ying; Flint, Lorraine E.; Berry, Joseph A.; Davis, Frank W.; Sperry, John S.; Field, Christopher B.

    2015-01-01

    The projected responses of forest ecosystems to warming and drying associated with twenty-first-century climate change vary widely from resiliency to widespread tree mortality1, 2, 3. Current vegetation models lack the ability to account for mortality of overstorey trees during extreme drought owing to uncertainties in mechanisms and thresholds causing mortality4, 5. Here we assess the causes of tree mortality, using field measurements of branch hydraulic conductivity during ongoing mortality in Populus tremuloides in the southwestern United States and a detailed plant hydraulics model. We identify a lethal plant water stress threshold that corresponds with a loss of vascular transport capacity from air entry into the xylem. We then use this hydraulic-based threshold to simulate forest dieback during historical drought, and compare predictions against three independent mortality data sets. The hydraulic threshold predicted with 75% accuracy regional patterns of tree mortality as found in field plots and mortality maps derived from Landsat imagery. In a high-emissions scenario, climate models project that drought stress will exceed the observed mortality threshold in the southwestern United States by the 2050s. Our approach provides a powerful and tractable way of incorporating tree mortality into vegetation models to resolve uncertainty over the fate of forest ecosystems in a changing climate.

  9. Global warming and the forest fire business in Canada

    International Nuclear Information System (INIS)

    Stocks, B.J.

    1991-01-01

    The current forest fire situation in Canada is outlined, and an attempt is made to predict the impact of global warming on the forest fire business in Canada. Despite the development of extremely sophisticated provincial and territorial fire management systems, forest fires continue to exert a tremendous influence on the Canadian forest resource. Research into the relationship between climate warming and forest fires has fallen into two categories: the effect of future global warming on fire weather severity, and the current contribution of forest fires to global atmospheric greenhouse gas budgets. A 46% increase in seasonal fire severity across Canada is suggested under a doubled atmospheric carbon dioxide concentration scenario. Approximately 89% of carbon released to the atmosphere by forest fire burning is in the form of carbon dioxide, 9% is carbon monoxide, and the remaining carbon is released as methane or non-methane hydrocarbons. It is estimated that forest fires in northern circumpolar countries contribute from 1-2% of the carbon released globally through biomass burning. Fire may be the agent by which a northerly shift of forest vegetation in Canada occurs. 13 refs., 2 figs

  10. Seasonal climate signals from multiple tree ring metrics: A case study of Pinus ponderosa in the upper Columbia River Basin

    Science.gov (United States)

    Dannenberg, Matthew P.; Wise, Erika K.

    2016-04-01

    Projected changes in the seasonality of hydroclimatic regimes are likely to have important implications for water resources and terrestrial ecosystems in the U.S. Pacific Northwest. The tree ring record, which has frequently been used to position recent changes in a longer-term context, typically relies on signals embedded in the total ring width of tree rings. Additional climatic inferences at a subannual temporal scale can be made using alternative tree ring metrics such as earlywood and latewood widths and the density of tree ring latewood. Here we examine seasonal precipitation and temperature signals embedded in total ring width, earlywood width, adjusted latewood width, and blue intensity chronologies from a network of six Pinus ponderosa sites in and surrounding the upper Columbia River Basin of the U.S. Pacific Northwest. We also evaluate the potential for combining multiple tree ring metrics together in reconstructions of past cool- and warm-season precipitation. The common signal among all metrics and sites is related to warm-season precipitation. Earlywood and latewood widths differ primarily in their sensitivity to conditions in the year prior to growth. Total and earlywood widths from the lowest elevation sites also reflect cool-season moisture. Effective correlation analyses and composite-plus-scale tests suggest that combining multiple tree ring metrics together may improve reconstructions of warm-season precipitation. For cool-season precipitation, total ring width alone explains more variance than any other individual metric or combination of metrics. The composite-plus-scale tests show that variance-scaled precipitation reconstructions in the upper Columbia River Basin may be asymmetric in their ability to capture extreme events.

  11. Remotely Sensed Northern Vegetation Response to Changing Climate: Growing Season and Productivity Perspective

    Science.gov (United States)

    Ganguly, S.; Park, Taejin; Choi, Sungho; Bi, Jian; Knyazikhin, Yuri; Myneni, Ranga

    2016-01-01

    Vegetation growing season and maximum photosynthetic state determine spatiotemporal variability of seasonal total gross primary productivity of vegetation. Recent warming induced impacts accelerate shifts on growing season and physiological status over Northern vegetated land. Thus, understanding and quantifying these changes are very important. Here, we first investigate how vegetation growing season and maximum photosynthesis state are evolved and how such components contribute on inter-annual variation of seasonal total gross primary productivity. Furthermore, seasonally different response of northern vegetation to changing temperature and water availability is also investigated. We utilized both long-term remotely sensed data to extract larger scale growing season metrics (growing season start, end and duration) and productivity (i.e., growing season summed vegetation index, GSSVI) for answering these questions. We find that regionally diverged growing season shift and maximum photosynthetic state contribute differently characterized productivity inter-annual variability and trend. Also seasonally different response of vegetation gives different view of spatially varying interaction between vegetation and climate. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses of northern vegetation to changing climate.

  12. Mass coral mortality under local amplification of 2 °C ocean warming

    Science.gov (United States)

    Decarlo, Thomas M.; Cohen, Anne L.; Wong, George T. F.; Davis, Kristen A.; Lohmann, Pat; Soong, Keryea

    2017-03-01

    A 2 °C increase in global temperature above pre-industrial levels is considered a reasonable target for avoiding the most devastating impacts of anthropogenic climate change. In June 2015, sea surface temperature (SST) of the South China Sea (SCS) increased by 2 °C in response to the developing Pacific El Niño. On its own, this moderate, short-lived warming was unlikely to cause widespread damage to coral reefs in the region, and the coral reef “Bleaching Alert” alarm was not raised. However, on Dongsha Atoll, in the northern SCS, unusually weak winds created low-flow conditions that amplified the 2 °C basin-scale anomaly. Water temperatures on the reef flat, normally indistinguishable from open-ocean SST, exceeded 6 °C above normal summertime levels. Mass coral bleaching quickly ensued, killing 40% of the resident coral community in an event unprecedented in at least the past 40 years. Our findings highlight the risks of 2 °C ocean warming to coral reef ecosystems when global and local processes align to drive intense heating, with devastating consequences.

  13. Latitudinal range influences the seasonal variation in the foraging behavior of marine top predators.

    Directory of Open Access Journals (Sweden)

    Stella Villegas-Amtmann

    Full Text Available Non-migratory resident species should be capable of modifying their foraging behavior to accommodate changes in prey abundance and availability associated with a changing environment. Populations that are better adapted to change will have higher foraging success and greater potential for survival in the face of climate change. We studied two species of resident central place foragers from temperate and equatorial regions with differing population trends and prey availability associated to season, the California sea lion (Zalophus californianus (CSL whose population is increasing and the endangered Galapagos sea lion (Zalophus wollebaeki (GSL whose population is declining. To determine their response to environmental change, we studied and compared their diving behavior using time-depth recorders and satellite location tags and their diet by measuring C and N isotope ratios during a warm and a cold season. Based on latitudinal differences in oceanographic productivity, we hypothesized that the seasonal variation in foraging behavior would differ for these two species. CSL exhibited greater seasonal variability in their foraging behavior as seen in changes to their diving behavior, foraging areas and diet between seasons. Conversely, GSL did not change their diving behavior between seasons, presenting three foraging strategies (shallow, deep and bottom divers during both. GSL exhibited greater dive and foraging effort than CSL. We suggest that during the warm and less productive season a greater range of foraging behaviors in CSL was associated with greater competition for prey, which relaxed during the cold season when resource availability was greater. GSL foraging specialization suggests that resources are limited throughout the year due to lower primary production and lower seasonal variation in productivity compared to CSL. These latitudinal differences influence their foraging success, pup survival and population growth reflected in

  14. Impact of climate change on heat-related mortality in Jiangsu Province, China.

    Science.gov (United States)

    Chen, Kai; Horton, Radley M; Bader, Daniel A; Lesk, Corey; Jiang, Leiwen; Jones, Bryan; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L

    2017-05-01

    A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Impact of Climate Change on Heat-Related Mortality in Jiangsu Province, China

    Science.gov (United States)

    Chen, Kai; Horton, Radley M.; Bader, Daniel A.; Lesk, Corey; Jiang, Leiwen; Jones, Bryan; Zhou, Lian; Chen, Xiaodong; Bi, Jun; Kinney, Patrick L.

    2017-01-01

    A warming climate is anticipated to increase the future heat-related total mortality in urban areas. However, little evidence has been reported for cause-specific mortality or nonurban areas. Here we assessed the impact of climate change on heat-related total and cause-specific mortality in both urban and rural counties of Jiangsu Province, China, in the next five decades. To address the potential uncertainty in projecting future heat-related mortality, we applied localized urban- and nonurban-specific exposure response functions, six population projections including a no population change scenario and five Shared Socioeconomic Pathways (SSPs), and 42 temperature projections from 21 global-scale general circulation models and two Representative Concentration Pathways (RCPs). Results showed that projected warmer temperatures in 2016-2040 and 2041-2065 will lead to higher heat-related mortality for total non-accidental, cardiovascular, respiratory, stroke, ischemic heart disease (IHD), and chronic obstructive pulmonary disease (COPD) causes occurring annually during May to September in Jiangsu Province, China. Nonurban residents in Jiangsu will suffer from more excess heat-related cause-specific mortality in 2016-2065 than urban residents. Variations across climate models and RCPs dominated the uncertainty of heat-related mortality estimation whereas population size change only had limited influence. Our findings suggest that targeted climate change mitigation and adaptation measures should be taken in both urban and nonurban areas of Jiangsu Province. Specific public health interventions should be focused on the leading causes of death (stroke, IHD, and COPD), whose health burden will be amplified by a warming climate.

  16. Changing seasonality patterns in Central Europe from Miocene Climate Optimum to Miocene Climate Transition deduced from the Crassostrea isotope archive

    Science.gov (United States)

    Harzhauser, Mathias; Piller, Werner E.; Müllegger, Stefan; Grunert, Patrick; Micheels, Arne

    2011-03-01

    The Western Tethyan estuarine oyster Crassostrea gryphoides is an excellent climate archive due to its large size and rapid growth. It is geologically long lived and allows a stable isotope-based insight into climatic trends during the Miocene. Herein we utilised the climate archive of 5 oyster shells from the Miocene Climate Optimum (MCO) and the subsequent Miocene Climate Transition (MCT) to evaluate changes of seasonality patterns. MCO shells exhibit highly regular seasonal rhythms of warm-wet and dry-cool seasons. Optimal conditions resulted in extraordinary growth rates of the oysters. δ 13C profiles are in phase with δ 18O although phytoplankton blooms may cause a slight offset. Estuarine waters during the MCO in Central Europe display a seasonal temperature range of c. 9-10 °C. Absolute water temperatures have ranged from 17 to 19 °C during cool seasons and up to 28 °C in warm seasons. Already during the early phase of the MCO, the growth rates are distinctly declining, although gigantic and extremely old shells have been formed at that time. Still, a very regular and well expressed seasonality is dominating the isotope profiles, but episodically occurring extreme climate events influence the environments. The seasonal temperature range is still c. 9 °C but the cool season temperature seems to be slightly lower (16 °C) and the warm season water temperature does not exceed c. 25 °C. In the later MCT at c. 12.5-12.0 Ma the seasonality pattern is breaking down and is replaced by successions of dry years with irregular precipitation events. No correlation between δ 18O and δ 13C is documented maybe due to a suboptimal nutrition level which would explain the low growth rates and small sizes. The amplitude of seasonal temperature range is decreasing to 5-8 °C. No clear cooling trend can be postulated for that time as the winter season water temperatures range from 15 to 20 °C. This may point to unstable precipitation rhythms on a multi-annual to

  17. Effects of air pollution on infant and children respiratory mortality in four large Latin-American cities.

    Science.gov (United States)

    Gouveia, Nelson; Junger, Washington Leite

    2018-01-01

    Air pollution is an important public health concern especially for children who are particularly susceptible. Latin America has a large children population, is highly urbanized and levels of pollution are substantially high, making the potential health impact of air pollution quite large. We evaluated the effect of air pollution on children respiratory mortality in four large urban centers: Mexico City, Santiago, Chile, and Sao Paulo and Rio de Janeiro in Brazil. Generalized Additive Models in Poisson regression was used to fit daily time-series of mortality due to respiratory diseases in infants and children, and levels of PM 10 and O 3 . Single lag and constrained polynomial distributed lag models were explored. Analyses were carried out per cause for each age group and each city. Fixed- and random-effects meta-analysis was conducted in order to combine the city-specific results in a single summary estimate. These cities host nearly 43 million people and pollution levels were above the WHO guidelines. For PM 10 the percentage increase in risk of death due to respiratory diseases in infants in a fixed effect model was 0.47% (0.09-0.85). For respiratory deaths in children 1-5 years old, the increase in risk was 0.58% (0.08-1.08) while a higher effect was observed for lower respiratory infections (LRI) in children 1-14 years old [1.38% (0.91-1.85)]. For O 3 , the only summarized estimate statistically significant was for LRI in infants. Analysis by season showed effects of O 3 in the warm season for respiratory diseases in infants, while negative effects were observed for respiratory and LRI deaths in children. We provided comparable mortality impact estimates of air pollutants across these cities and age groups. This information is important because many public policies aimed at preventing the adverse effects of pollution on health consider children as the population group that deserves the highest protection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 20th-Century Climate Change over Africa: Seasonal Variation in Hydroclimate Trends and Sahara Desert Extent

    Science.gov (United States)

    Nigam, S.; Thomas, N. P.

    2017-12-01

    Twentieth-century trends in seasonal temperature and precipitation over the African continent are analyzed from observational data sets and historical climate simulations. Given the agricultural economy of the continent, a seasonal perspective is adopted as it is more pertinent than an annual-average one which can mask off-setting but agriculturally-sensitive seasonal hydroclimate variations. Examination of linear trends in seasonal surface air temperature (SAT) shows that heat stress has increased in several regions, including Sudan and Northern Africa where largest SAT trends occur in the warm season. Broadly speaking, the northern continent has warmed more than the southern one in all seasons. Precipitation trends are varied but notable declining trends are found in the countries along the Gulf of Guinea, especially in the source region of Niger river in West Africa, and in the Congo river basin. Rainfall over the African Great Lakes - one of the largest freshwater repositories - has however increased. We show that the Sahara Desert has expanded significantly over the 20th century - by 12-20% depending on the season. The desert expanded southward in summer, reflecting retreat of the northern edge of the Sahel rainfall belt; and to the north in winter, indicating potential impact of the widening of the Tropics. Specific mechanisms driving the expansion in each season are investigated. Finally, this observational analysis is used to evaluate the state-of-the-art climate models from a comparison of the 20th-century hydroclimate trends with those manifest in historical climate simulations. The evaluation shows that modeling regional hydroclimate change over the Africa continent remains challenging.

  19. Declining global warming effects on the phenology of spring leaf unfolding.

    Science.gov (United States)

    Fu, Yongshuo H; Zhao, Hongfang; Piao, Shilong; Peaucelle, Marc; Peng, Shushi; Zhou, Guiyun; Ciais, Philippe; Huang, Mengtian; Menzel, Annette; Peñuelas, Josep; Song, Yang; Vitasse, Yann; Zeng, Zhenzhong; Janssens, Ivan A

    2015-10-01

    Earlier spring leaf unfolding is a frequently observed response of plants to climate warming. Many deciduous tree species require chilling for dormancy release, and warming-related reductions in chilling may counteract the advance of leaf unfolding in response to warming. Empirical evidence for this, however, is limited to saplings or twigs in climate-controlled chambers. Using long-term in situ observations of leaf unfolding for seven dominant European tree species at 1,245 sites, here we show that the apparent response of leaf unfolding to climate warming (ST, expressed in days advance of leaf unfolding per °C warming) has significantly decreased from 1980 to 2013 in all monitored tree species. Averaged across all species and sites, ST decreased by 40% from 4.0 ± 1.8 days °C(-1) during 1980-1994 to 2.3 ± 1.6 days °C(-1) during 1999-2013. The declining ST was also simulated by chilling-based phenology models, albeit with a weaker decline (24-30%) than observed in situ. The reduction in ST is likely to be partly attributable to reduced chilling. Nonetheless, other mechanisms may also have a role, such as 'photoperiod limitation' mechanisms that may become ultimately limiting when leaf unfolding dates occur too early in the season. Our results provide empirical evidence for a declining ST, but also suggest that the predicted strong winter warming in the future may further reduce ST and therefore result in a slowdown in the advance of tree spring phenology.

  20. Warm Handoffs: a Novel Strategy to Improve End-of-Rotation Care Transitions.

    Science.gov (United States)

    Saag, Harry S; Chen, Jingjing; Denson, Joshua L; Jones, Simon; Horwitz, Leora; Cocks, Patrick M

    2018-01-01

    Hospitalized medical patients undergoing transition of care by house staff teams at the end of a ward rotation are associated with an increased risk of mortality, yet best practices surrounding this transition are lacking. To assess the impact of a warm handoff protocol for end-of-rotation care transitions. A large, university-based internal medicine residency using three different training sites. PGY-2 and PGY-3 internal medicine residents. Implementation of a warm handoff protocol whereby the incoming and outgoing residents meet at the hospital to sign out in-person and jointly round at the bedside on sicker patients using a checklist. An eight-question survey completed by 60 of 99 eligible residents demonstrated that 85% of residents perceived warm handoffs to be safer for patients (p rotation (p rotation care transitions. Additional studies analyzing patient outcomes will be needed to assess the impact of this strategy.

  1. Dynamics behind warming of the southeastern Arabian Sea and its interruption based on in situ measurements

    Science.gov (United States)

    Mathew, Simi; Natesan, Usha; Latha, Ganesan; Venkatesan, Ramasamy

    2018-05-01

    A study of the inter-annual variability of the warming of the southeastern Arabian Sea (SEAS) during the spring transition months was carried out from 2013 to 2015 based on in situ data from moored buoys. An attempt was made to identify the roles of the different variables in the warming of the SEAS (e.g., net heat flux, advection, entrainment, and thickness of the barrier layer during the previous northeast monsoon season). The intense freshening of the SEAS (approximately 2 PSU) occurring in each December, together with the presence of a downwelling Rossby wave, supports the formation of a thick barrier layer during the northeast monsoon season. It is known that the barrier layer thickness, varying each year, plays a major role in the spring warming of the SEAS. Interestingly, an anomalously thick barrier layer occurred during the northeast monsoon season of 2012-2013. However, the highest sea surface temperature (31 °C) was recorded during the last week of April 2015, while the lowest sea surface temperature (29.7 °C) was recorded during the last week of May 2013. The mixed layer heat budget analysis during the spring transition months proved that the intense warming has been mainly supported by the net heat flux, not by other factors like advection and entrainment. The inter-annual variability analysis of the net heat flux and its components, averaged over a box region of the SEAS, showed a substantial latent heat flux release and a reduction in net shortwave radiation in 2013. Both factors contributed to the negative net heat flux. Strong breaks in the warming were also observed in May due to the entrainment of cold sub-surface waters. These events are associated with the cyclonic eddy persisting over the SEAS during the same time. The entrainment term, favoring the cooling, was stronger in 2015 than that in 2013 and 2014. The surface temperatures measured in 2013 were lower than those in 2014 and 2015 despite the presence of a thick barrier layer. The

  2. Impact of ocean acidification and warming on the productivity of a rock pool community.

    Science.gov (United States)

    Legrand, Erwann; Riera, Pascal; Bohner, Olivier; Coudret, Jérôme; Schlicklin, Ferdinand; Derrien, Marie; Martin, Sophie

    2018-05-01

    This study examined experimentally the combined effect of ocean acidification and warming on the productivity of rock pool multi-specific assemblages, composed of coralline algae, fleshy algae, and grazers. Natural rock pool communities experience high environmental fluctuations. This may confer physiological advantage to rock pool communities when facing predicted acidification and warming. The effect of ocean acidification and warming have been assessed at both individual and assemblage level to examine the importance of species interactions in the response of assemblages. We hypothesized that rock pool assemblages have physiological advantage when facing predicted ocean acidification and warming. Species exhibited species-specific responses to increased temperature and pCO 2 . Increased temperature and pCO 2 have no effect on assemblage photosynthesis, which was mostly influenced by fleshy algal primary production. The response of coralline algae to ocean acidification and warming depended on the season, which evidenced the importance of physiological adaptations to their environment in their response to climate change. We suggest that rock pool assemblages are relatively robust to changes in temperature and pCO 2 , in terms of primary production. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Winter excess in hospital admissions, in-patient mortality and length of acute hospital stay in stroke: a hospital database study over six seasonal years in Norfolk, UK.

    Science.gov (United States)

    Myint, Phyo K; Vowler, Sarah L; Woodhouse, Peter R; Redmayne, Oliver; Fulcher, Robert A

    2007-01-01

    Several studies have examined the incidence and mortality of stroke in relation to season. However, the evidence is conflicting partly due to variation in the populations (community vs. hospital-based), and in climatic conditions between studies. Moreover, they may not have been able to take into account the age, sex and stroke type of the study population. We hypothesized that the age, sex and type of stroke are major determinants of the presence or absence of winter excess in morbidity and mortality associated with stroke. We analyzed a hospital-based stroke register from Norfolk, UK to examine our prior hypothesis. Using Curwen's method, we performed stratified sex-specific analyses by (1) seasonal year and (2) quartiles of patients' age and stroke subtype and calculated the winter excess for the number of admissions, in-patient deaths and length of acute hospital stay. There were 5,481 patients (men=45%). Their ages ranged from 17 to 105 years (median=78 years). There appeared to be winter excess in hospital admissions, deaths and length of acute hospital stay overall accounting for 3/100,000 extra admissions (winter excess index of 3.4% in men and 7.6% in women) and 1/100,000 deaths (winter excess index of 4.7 and 8.6% in women) due to stroke in winter compared to non-winter periods. Older patients with non-haemorrhagic stroke mainly contribute to this excess. If our findings are replicated throughout England and Wales, it is estimated that there are 1,700 excess admissions, 600 excess in-patient deaths and 24,500 extra acute hospital bed days each winter, related to stroke within the current population of approximately 60 million. Further research should be focused on the determinants of winter excess in morbidity and mortality associated with stroke. This may subsequently reduce the morbidity and mortality by providing effective preventive strategies in future. (c) 2007 S. Karger AG, Basel.

  4. Global warming in the context of 2000 years of Australian alpine temperature and snow cover.

    Science.gov (United States)

    McGowan, Hamish; Callow, John Nikolaus; Soderholm, Joshua; McGrath, Gavan; Campbell, Micheline; Zhao, Jian-Xin

    2018-03-13

    Annual resolution reconstructions of alpine temperatures are rare, particularly for the Southern Hemisphere, while no snow cover reconstructions exist. These records are essential to place in context the impact of anthropogenic global warming against historical major natural climate events such as the Roman Warm Period (RWP), Medieval Climate Anomaly (MCA) and Little Ice Age (LIA). Here we show for a marginal alpine region of Australia using a carbon isotope speleothem reconstruction, warming over the past five decades has experienced equivalent magnitude of temperature change and snow cover decline to the RWP and MCA. The current rate of warming is unmatched for the past 2000 years and seasonal snow cover is at a minimum. On scales of several decades, mean maximum temperatures have undergone considerable change ≈ ± 0.8 °C highlighting local scale susceptibility to rapid temperature change, evidence of which is often masked in regional to hemisphere scale temperature reconstructions.

  5. Physical mechanisms of spring and summertime drought related with the global warming over the northern America

    Science.gov (United States)

    Choi, W.; Kim, K. Y.

    2017-12-01

    Drought during the growing season (spring through summer) is severe natural hazard in the large cropland over the northern America. It is important to understand how the drought is related with the global warming and how it will change in the future. This study aims to investigate the physical mechanism of global warming impact on the spring and summertime drought over the northern America using Cyclostationary Empirical Orthogonal Function (CSEOF) analysis. The Northern Hemisphere surface warming, the most dominant mode of the surface air temperature, has resulted in decreased relative humidity and precipitation over the mid-latitude region of North America. For the viewpoint of atmospheric water demand, soil moisture and evaporation have also decreased significantly, exacerbating vulnerability of drought. These consistent features of changes in water demand and supply related with the global warming can provide a possibility of credible insight for future drought change.

  6. Seasonality of suicide deaths in Serbia, 1990-2012

    Directory of Open Access Journals (Sweden)

    Penev Goran

    2014-01-01

    Full Text Available Background: In the period from 1990 to 2012, there were 32,855 suicides registered in Serbia, i.e. an average of 1428 deaths per year (18.9 per 100.000 inhabitants. The suicides were the most frequent in the early 1990s, less frequent during the 2000s, and least frequent in the last three years of the observed period (2010-2012 - an average of 1237 suicides per year. Objective: The goal of this paper is to evaluate the seasonal variations of suicides in Serbia in the period of 1990-2012, their changes, as well as the accordance with findings from other countries. Method: In the paper are used "classical" statistical methods of evaluating cyclical variations (χ2-test, Edwards' test as well as some frequently used newer methods (e.g. the peak-low ratio. It also introduces a new indicator of the intensity of monthly variations in suicides (the magnitude of trimester variations of /12/ moving consecutive months index - the MtMV index. Seasonality of suicides is also observed by sex. Results: The results of the research of seasonality confirm that certain cyclical variations in mortality due to suicide are also present in Serbia. Observed by season, suicides are most frequent in spring and summer and less in winter. The cyclical nature was also clearly confirmed by month. Suicides are most frequent in "warm" months (April-August and far less frequent in "cold" months (December-February. By month, suicides are most frequent in May, while the maximal average number of suicides per day was calculated for June (21 % higher than the average for 1990-2012. December is singled out as the month with the lowest number as well as lowest daily average of suicides (25 % lower than the average. Conclusion: The cyclical nature of suicides is clearly notable during the entire observed period and no significant fluctuations or decrease in the intensity of the variation were observed. Regardless of the method of analysis, the resulting conclusions are identical

  7. Risk assessment for cardiovascular and respiratory mortality due to air pollution and synoptic meteorology in 10 Canadian cities.

    Science.gov (United States)

    Vanos, Jennifer K; Hebbern, Christopher; Cakmak, Sabit

    2014-02-01

    Synoptic weather and ambient air quality synergistically influence human health. We report the relative risk of mortality from all non-accidental, respiratory-, and cardiovascular-related causes, associated with exposure to four air pollutants, by weather type and season, in 10 major Canadian cities for 1981 through 1999. We conducted this multi-city time-series study using Poisson generalized linear models stratified by season and each of six distinctive synoptic weather types. Statistically significant relationships of mortality due to short-term exposure to carbon monoxide, nitrogen dioxide, sulphur dioxide, and ozone were found, with significant modifications of risk by weather type, season, and mortality cause. In total, 61% of the respiratory-related mortality relative risk estimates were significantly higher than for cardiovascular-related mortality. The combined effect of weather and air pollution is greatest when tropical-type weather is present in the spring or summer. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  8. Climatic limits on foliar growth during major droughts in the southwestern USA

    Science.gov (United States)

    Weiss, Jeremy L.; Betancourt, Julio L.; Overpeck, Jonathan T.

    2012-09-01

    Pronounced droughts during the 1950s and 2000s in the American Southwest provide an opportunity to compare mesoscale ecosystem responses to anomalously dry conditions before and during the regional warming that started in the late 1970s. This year-round warming has produced fewer cool season freezes, losses in regional snowpack, an 8-10 day advance in spring onset, and hotter summers, all of which should affect vegetation differently across seasons and elevations. Here, we examine indices that represent climatic limits on foliar growth for both drought periods and evaluate these indices for areas that experienced tree mortality during the 2000s drought. Relative to the 1950s drought, warmer conditions during the 2000s drought decreased the occurrence of temperatures too low for foliar growth at lower elevations in winter and higher elevations in summer. Higher vapor pressure deficits (VPDs), largely driven by warmer temperatures in the more recent drought, were more limiting to foliar growth from spring through summer at lower and middle elevations. At many locations where tree mortality occurred during the 2000s drought, low-temperature constraints on foliar growth were extremely unlimiting, whereas VPD constraints were extremely limiting from early spring through late autumn. Our analysis shows that in physiographically complex regions such as the Southwest, seasonality and elevational gradients are important for understanding vegetative responses to warming. It also suggests that continued warming will both increase the degree to which VPD limits foliar growth during future droughts and expand its reach to higher elevations and other seasons.

  9. Human mortality seasonality in Castile-León, Spain, between 1980 and 1998: the influence of temperature, pressure and humidity

    Science.gov (United States)

    Fernández-Raga, María; Tomás, Clemente; Fraile, Roberto

    2010-07-01

    This study was carried out in the region of Castile and Leon, Spain, from 1980 to 1998 and analyzes the relationship between the number of monthly deaths caused by cardiovascular, respiratory and digestive diseases and three meteorological variables: temperature, pressure and humidity. One of the innovations in this study is the application of principal component analysis in a way that differs from its usual application: one single series representing the whole region was constructed for each meteorological variable from the series of eight weather stations. Annual and seasonal mortality trends were also studied. Cardiovascular diseases are the leading cause of death in Castile and Leon. The mortality related to cardiovascular, respiratory and digestive systems shows a statistically significant rising trend across the study period (an annual increase of 6, 16 and 4‰, respectively). The pressure at which mortality is lowest is approximately the same for all causes of death (about 915 hPa), but temperature values vary greatly (16.8-19.7°C for the mean, 10.9-18.1°C for the minimum, and 24.1-27.2°C for the maximum temperature). The most comfortable temperatures for patients with cardiovascular diseases (16.8°C) are apparently lower than those for patients with respiratory diseases (18.1°C), which are, in turn, lower than in the case of diseases of the digestive system (19.7°C). Finally, the optimal humidity for patients with respiratory diseases is the lowest (24%) among the diseases, and the highest (51%) corresponds to diseases of the digestive system, while the optimal relative humidity for the cardiovascular system is 45%.

  10. Health effects of global warming: Problems in assessment

    International Nuclear Information System (INIS)

    Longstreth, J.

    1993-06-01

    Global warming is likely to result in a variety of environmental effects ranging from impacts on species diversity, changes in population size in flora and fauna, increases in sea level and possible impacts on the primary productivity of the sea. Potential impacts on human health and welfare have included possible increases in heat related mortality, changes in the distribution of disease vectors, and possible impacts on respiratory diseases including hayfever and asthma. Most of the focus thus far is on effects which are directly related to increases in temperature, e.g., heat stress or perhaps one step removed, e.g., changes in vector distribution. Some of the more severe impacts are likely to be much less direct, e.g., increases in migration due to agricultural failure following prolonged droughts. This paper discusses two possible approaches to the study of these less-direct impacts of global warming and presents information from on-going research using each of these approaches

  11. Compensatory mechanisms mitigate the effect of warming and drought on wood formation.

    Science.gov (United States)

    Balducci, Lorena; Cuny, Henri E; Rathgeber, Cyrille B K; Deslauriers, Annie; Giovannelli, Alessio; Rossi, Sergio

    2016-06-01

    Because of global warming, high-latitude ecosystems are expected to experience increases in temperature and drought events. Wood formation will have to adjust to these new climatic constraints to maintain tree mechanical stability and long-distance water transport. The aim of this study is to understand the dynamic processes involved in wood formation under warming and drought. Xylogenesis, gas exchange, water relations and wood anatomy of black spruce [Picea mariana (Mill.) B.S.P.] saplings were monitored during a greenhouse experiment where temperature was increased during daytime or night-time (+6 °C) combined with a drought period. The kinetics of tracheid development expressed as rate and duration of the xylogenesis sub-processes were quantified using generalized additive models. Drought and warming had a strong influence on cell production, but little effect on wood anatomy. The increase in cell production rate under warmer temperatures, and especially during the night-time warming at the end of the growing season, resulted in wider tree-rings. However, the strong compensation between rates and durations of cell differentiation processes mitigates warming and drought effects on tree-ring structure. Our results allowed quantification of how wood formation kinetics is regulated when water and heat stress increase, allowing trees to adapt to future environmental conditions. © 2015 John Wiley & Sons Ltd.

  12. Daytime warming has stronger negative effects on soil nematodes than night-time warming

    OpenAIRE

    Yan, Xiumin; Wang, Kehong; Song, Lihong; Wang, Xuefeng; Wu, Donghui

    2017-01-01

    Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatmen...

  13. Mortality of Kalliapseudes schubartii in unvegetated soft bottoms of the estuarine region of the Lagoa dos Patos

    Directory of Open Access Journals (Sweden)

    Fonseca Duane Barros

    2006-01-01

    Full Text Available Studies were carried iut on seasonal mortality by taking samples of Kalliapseudes schubartii (Crustacea: Tanaidacea for a year in the estuarine region of the Lagoa dos Patos (southern Brazil. Results demonstrated no significant difference in seasonal mortality rates, which suggest that populations of K. schubartii was heavily preyed on year round and that an assumption of a significantly higher mortality in summer/autumn than in spring/winter might not be held in unvegetated soft bottoms of the estuarine regions of the Lagoa dos Patos.

  14. Factors Influencing Knowledge, Food Safety Practices and Food Preferences During Warm Weather of Salmonella and Campylobacter Cases in South Australia.

    Science.gov (United States)

    Milazzo, Adriana; Giles, Lynne C; Zhang, Ying; Koehler, Ann P; Hiller, Janet E; Bi, Peng

    2017-03-01

    To assess food safety practices, food shopping preferences, and eating behaviors of people diagnosed with Salmonella or Campylobacter infection in the warm seasons, and to identify socioeconomic factors associated with behavior and practices. A cross-sectional survey was conducted among Salmonella and Campylobacter cases with onset of illness from January 1 to March 31, 2013. Multivariable logistic regression analyses examined relationships between socioeconomic position and food safety knowledge and practices, shopping and food preferences, and preferences, perceptions, and knowledge about food safety information on warm days. Respondents in our study engaged in unsafe personal and food hygiene practices. They also carried out unsafe food preparation practices, and had poor knowledge of foods associated with an increased risk of foodborne illness. Socioeconomic position did not influence food safety practices. We found that people's reported eating behaviors and food preferences were influenced by warm weather. Our study has explored preferences and practices related to food safety in the warm season months. This is important given that warmer ambient temperatures are projected to rise, both globally and in Australia, and will have a substantial effect on the burden of infectious gastroenteritis including foodborne disease. Our results provide information about modifiable behaviors for the prevention of foodborne illness in the household in the warm weather and the need for information to be disseminated across the general population. An understanding of the knowledge and factors associated with human behavior during warmer weather is critical for public health interventions on foodborne prevention.

  15. Effects of experimental warming and nitrogen addition on soil respiration and CH4 fluxes from crop rotations of winter wheat–soybean/fallow

    DEFF Research Database (Denmark)

    Liu, L; Hu, C; Yang, P

    2015-01-01

    Soil respiration and CH4 emissions play a significant role in the global carbon balance. However, in situ studies in agricultural soils on responses of soil respiration and CH4 fluxes to climate warming are still sparse, especially from long-term studies with year-round heating. A warming...... by affecting soil NH4 concentration. Across years, CH4 emissions were negatively correlated with soil temperature in N1 treatment. Soil respiration showed clear seasonal fluctuations, with the largest emissions during summer and smallest in winter. Warming and nitrogen fertilization had no significant effects...... on total cumulative soil CO2 fluxes. Soil respiration was positively correlated with microbial biomass C, and microbial biomass C was not affected significantly by warming or nitrogen addition. The lack of significant effects of warming on soil respiration may have resulted from: (1) warming-induced soil...

  16. Development of new techniques of using irradiation in the genetic improvement of warm season grasses and an assessment of the genetic and cytogenetic effects. Progress report, November 1, 1977--October 31, 1978

    International Nuclear Information System (INIS)

    Hanna, W.W.; Burton, G.W.

    1978-05-01

    Progress is reported on plant breeding programs for the genetic improvement of warm season grasses using irradiation as a tool. Data are included from studies on alteration of the protein quantity and quality in pearl millet grain by irradiation and mutation breeding; the effects of nitrogen and genotype on pearl millet grain; the effects of seed size on quality in pearl millet; irradiation breeding of sterile triploid turf Bermuda grasses; irradiation breeding of sterile coastcross-1, a forage grass, to increase winter hardiness; use of irradiation to induce resistance to rust disease; and an economic assessment of irradiation-induced mutants for plant breeding programs

  17. Effects of elevated CO2, warming and drought episodes on plant carbon uptake in a temperate heath ecosystem are controlled by soil water status

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard

    2011-01-01

    The impact of elevated CO2, periodic drought and warming on photosynthesis and leaf characteristics of the evergreen dwarf shrub Calluna vulgaris in a temperate heath ecosystem was investigated. Photosynthesis was reduced by drought in midsummer and increased by elevated CO2 throughout the growing...... season, whereas warming only stimulated photosynthesis early in the year. At the beginning and end of the growing season, a T × CO2 interaction synergistically stimulated plant carbon uptake in the combination of warming and elevated CO2. At peak drought, the D × CO2 interaction antagonistically down......-regulated photosynthesis, suggesting a limited ability of elevated CO2 to counteract the negative effect of drought. The response of photosynthesis in the full factorial combination (TDCO2) could be explained by the main effect of experimental treatments (T, D, CO2) and the two-factor interactions (D × CO2, T × CO2...

  18. Warm Season Storms, Floods, and Tributary Sand Inputs below Glen Canyon Dam: Investigating Salience to Adaptive Management in the Context of a 10-Year Long Controlled Flooding Experiment in Grand Canyon National Park, AZ, USA

    Science.gov (United States)

    Jain, S.; Melis, T. S.; Topping, D. J.; Pulwarty, R. S.; Eischeid, J.

    2013-12-01

    The planning and decision processes in the Glen Canyon Dam Adaptive Management Program (GCDAMP) strive to balance numerous, often competing, objectives, such as, water supply, hydropower generation, low flow maintenance, maximizing conservation of downstream tributary sand supply, endangered native fish, and other sociocultural resources of Glen Canyon National Recreation Area and Grand Canyon National Park. In this context, use of monitored and predictive information on the warm season floods (at point-to-regional scales) has been identified as lead-information for a new 10-year long controlled flooding experiment (termed the High-Flow Experiment Protocol) intended to determine management options for rebuilding and maintaining sandbars in Grand Canyon; an adaptive strategy that can potentially facilitate improved planning and dam operations. In this work, we focus on a key concern identified by the GCDAMP, related to the timing and volume of tributary sand input from the Paria and Little Colorado Rivers (located 26 and 124 km below the dam, respectively) into the Colorado River in Grand Canyon National Park. Episodic and intraseasonal variations (with links to equatorial and sub-tropical Pacific sea surface temperature variability) in the southwest hydroclimatology are investigated to understand the magnitude, timing and spatial scales of warm season floods from this relatively small, but prolific sand producing drainage of the semi-arid Colorado Plateau. The coupled variations of the flood-driven sediment input (magnitude and timing) from these two drainages into the Colorado River are also investigated. The physical processes, including diagnosis of storms and moisture sources, are mapped alongside the planning and decision processes for the ongoing experimental flood releases from the Glen Canyon Dam which are aimed at achieving restoration and maintenance of sandbars and instream ecology. The GCDAMP represents one of the most visible and widely recognized

  19. Synergistic impacts of global warming on the resilience of coral reefs

    OpenAIRE

    Bozec, Yves-Marie; Mumby, Peter J.

    2015-01-01

    Recent epizootics have removed important functional species from Caribbean coral reefs and left communities vulnerable to alternative attractors. Global warming will impact reefs further through two mechanisms. A chronic mechanism reduces coral calcification, which can result in depressed somatic growth. An acute mechanism, coral bleaching, causes extreme mortality when sea temperatures become anomalously high. We ask how these two mechanisms interact in driving future reef state (coral cover...

  20. Detecting Climate Signals in Precipitation Extremes from TRMM (1998-2013) - Increasing Contrast Between Wet and Dry Extremes During the "Global Warming Hiatus"

    Science.gov (United States)

    Wu, Huey-Tzu Jenny; Lau, William K.-M.

    2016-01-01

    We investigate changes in daily precipitation extremes using Tropical Rainfall Measuring Mission (TRMM) data (1998-2013), which coincides with the "global warming hiatus." Results show a change in probability distribution functions of local precipitation events (LPEs) during this period consistent with previous global warming studies, indicating increasing contrast between wet and dry extremes, with more intense LPE, less moderate LPE, and more dry (no rain) days globally. Analyses for land and ocean separately reveal more complex and nuanced changes over land, characterized by a strong positive trend (+12.0% per decade, 99% confidence level (c.l.)) in frequency of extreme LPEs over the Northern Hemisphere extratropics during the wet season but a negative global trend (-6.6% per decade, 95% c.l.) during the dry season. A significant global drying trend (3.2% per decade, 99% c.l.) over land is also found during the dry season. Regions of pronounced increased dry events include western and central U.S., northeastern Asia, and Southern Europe/Mediterranean.

  1. Increasing potential of biomass burning over Sumatra, Indonesia induced by anthropogenic tropical warming

    International Nuclear Information System (INIS)

    Lestari, R Kartika; Watanabe, Masahiro; Kimoto, Masahide; Imada, Yukiko; Shiogama, Hideo; Field, Robert D; Takemura, Toshihiko

    2014-01-01

    Uncontrolled biomass burning in Indonesia during drought periods damages the landscape, degrades regional air quality, and acts as a disproportionately large source of greenhouse gas emissions. The expansion of forest fires is mostly observed in October in Sumatra favored by persistent droughts during the dry season from June to November. The contribution of anthropogenic warming to the probability of severe droughts is not yet clear. Here, we show evidence that past events in Sumatra were exacerbated by anthropogenic warming and that they will become more frequent under a future emissions scenario. By conducting two sets of atmospheric general circulation model ensemble experiments driven by observed sea surface temperature for 1960–2011, one with and one without an anthropogenic warming component, we found that a recent weakening of the Walker circulation associated with tropical ocean warming increased the probability of severe droughts in Sumatra, despite increasing tropical-mean precipitation. A future increase in the frequency of droughts is then suggested from our analyses of the Coupled Model Intercomparison Project Phase 5 model ensembles. Increasing precipitation to the north of the equator accompanies drier conditions over Indonesia, amplified by enhanced ocean surface warming in the central equatorial Pacific. The resultant precipitation decrease leads to a ∼25% increase in severe drought events from 1951–2000 to 2001–2050. Our results therefore indicate the global warming impact to a potential of wide-spreading forest fires over Indonesia, which requires mitigation policy for disaster prevention. (letter)

  2. Daytime warming has stronger negative effects on soil nematodes than night-time warming

    Science.gov (United States)

    Yan, Xiumin; Wang, Kehong; Song, Lihong; Wang, Xuefeng; Wu, Donghui

    2017-03-01

    Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatment significantly decreased soil nematodes density, and night-time warming treatment marginally affected the density. The response of bacterivorous nematode and fungivorous nematode to experimental warming showed the same trend with the total density. Redundancy analysis revealed an opposite effect of soil moisture and soil temperature, and the most important of soil moisture and temperature in night-time among the measured environment factors, affecting soil nematode community. Our findings suggested that daily minimum temperature and warming induced drying are most important factors affecting soil nematode community under the current global asymmetric warming.

  3. Drilling comparison in "warm ice" and drill design comparison

    DEFF Research Database (Denmark)

    Augustin, L.; Motoyama, H.; Wilhelms, F.

    2007-01-01

    For the deep ice-core drilling community, the 2005/06 Antarctic season was an exciting and fruitful one. In three different Antarctic locations, Dome Fuji, EPICA DML and Vostok, deep drillings approached bedrock (the ice-water interface in the case of Vostok), emulating what had previously been...... achieved at NorthGRIP, Greenland, (summer 2003 and 2004) and at EPICA Dome C2, Antarctica (season 2004/05). For the first time in ice-core drilling history, three different types of drill (KEMS, JARE and EPICA) simultaneously reached the depth of 'warm ice' under high pressure. After excellent progress...... at each site, the drilling rate dropped and the drilling teams had to deal with refrozen ice on cutters and drill heads. Drills have different limits and perform differently. In this comparative study, we examine depth, pressure, temperature, pump flow and cutting speed. Finally, we compare a few...

  4. The relationship of lightning activity and short-duration rainfall events during warm seasons over the Beijing metropolitan region

    Science.gov (United States)

    Wu, Fan; Cui, Xiaopeng; Zhang, Da-Lin; Qiao, Lin

    2017-10-01

    The relationship between lightning activity and rainfall associated with 2925 short-duration rainfall (SDR) events over the Beijing metropolitan region (BMR) is examined during the warm seasons of 2006-2007, using the cloud-to-ground (CG) and intracloud (IC) lightning data from Surveillance et Alerte Foudre par Interférometrie Radioélectrique (SAFIR)-3000 and 5-min rainfall data from automatic weather stations (AWSs). An optimal radius of 10 km around selected AWSs is used to determine the lightning-rainfall relationship. The lightning-rainfall correlations vary significantly, depending upon the intensity of SDR events. That is, correlation coefficient (R 0.7) for the short-duration heavy rainfall (SDHR, i.e., ≥ 20 mm h- 1) events is found higher than that (R 0.4) for the weak SDR (i.e., 5-10 mm h- 1) events, and lower percentage of the SDHR events (< 10%) than the weak SDR events (40-50%) are observed with few flashes. Significant time-lagged correlations between lightning and rainfall are also found. About 80% of the SDR events could reach their highest correlation coefficients when the associated lightning flashes shift at time lags of < 25 min before and after rainfall begins. Those events with lightning preceding rainfall account for 50-60% of the total SDR events. Better lightning-rainfall correlations can be attained when time lags are incorporated, with the use of total (CG and IC) lightning data. These results appear to have important implications for improving the nowcast of SDHR events.

  5. Assessing the magnitude and timing of anthropogenic warming of a shallow aquifer: example from Virginia Beach, USA

    Science.gov (United States)

    Eggleston, John R.; McCoy, Kurt J.

    2015-01-01

    Groundwater temperature measurements in a shallow coastal aquifer in Virginia Beach, Virginia, USA, suggest groundwater warming of +4.1 °C relative to deeper geothermal gradients. Observed warming is related to timing and depth of influence of two potential thermal drivers—atmospheric temperature increases and urbanization. Results indicate that up to 30 % of groundwater warming at the water table can be attributed to atmospheric warming while up to 70 % of warming can be attributed to urbanization. Groundwater temperature readings to 30-m depth correlate positively with percentage of impervious cover and negatively with percentage of tree canopy cover; thus, these two land-use metrics explain up to 70 % of warming at the water table. Analytical and numerical modeling results indicate that an average vertical groundwater temperature profile for the study area, constructed from repeat measurement at 11 locations over 15 months, is consistent with the timing of land-use change over the past century in Virginia Beach. The magnitude of human-induced warming at the water table (+4.1 °C) is twice the current seasonal temperature variation, indicating the potential for ecological impacts on wetlands and estuaries receiving groundwater discharge from shallow aquifers.

  6. Observed and Projected Changes in Thermal Growing Degree-Days and Growing Season and Their Divergent Responses to Warming over China

    Science.gov (United States)

    Deng, H.

    2017-12-01

    Vegetation growth and phenology are largely regulated by the growing degree-days (GDD) and growing season (GS). By choosing 0°C, 5°C and 10°C, three key based temperatures (Tb) for vegetation growth, the GDD and GS in China during the observed period (1960-2011) were developed using homogenized daily mean temperatures (Td) in 536 meteorological stations. In addition, the GDD10 and GS10 in China were projected under the representative concentration pathway scenarios (RCPs) during 1961-2099, using the Td (0.5°×0.5°) derived from five general circulation models (GCMs), after model evaluation. Advance in the start of the growing season (SOS; 4.86-6.71 days; SOS0 > SOS5 > SOS10) and delay in the end of the growing season (EOS; 4.32-6.19 days; EOS0 GDD5 > GDD10), in China as a whole. Each observed variation has a substantial acceleration mostly in 1987 or 1996, and a speed reduction or a trend reversal in the early 2000s. Increases in the GDD10 and GS10 would continue in the 21st century, causing northward shifts in the temperature zones. Finally in the long-term (2071-2099), the nationally average GDD10 and GS10 would be 279.1°C·d higher and 16.5 d longer for RCP 2.6, and 964.4°C·d higher and 50.3 d longer for RCP 8.5, relative to 1981-2010. Regionally, the GDD enhancement were stronger in the tropics, east, northeast and northwest China during the observed period, and tend to be in southern China in the future. The largest GS extensions are consistently in the eastern and southern parts of the Tibetan Alpine zone, particularly in the future. During the observed period, advance in SOS and delay in EOS drove the GS extensions in the eastern monsoon zone and northwest arid/semi-arid zone respectively. In the future, an advanced SOS drives the GS extension in the northern (> ca. 33°N) Tibetan Alpine zone, the mountainous areas in northeast China, and south of the Tropic of Cancer. The GDD and GS showed positive sensitivity to the temperature (GDD0 > GDD5 > GDD10

  7. A century of ocean warming on Florida Keys coral reefs: historic in situ observations

    Science.gov (United States)

    Kuffner, Ilsa B.; Lidz, Barbara H.; Hudson, J. Harold; Anderson, Jeffery S.

    2015-01-01

    There is strong evidence that global climate change over the last several decades has caused shifts in species distributions, species extinctions, and alterations in the functioning of ecosystems. However, because of high variability on short (i.e., diurnal, seasonal, and annual) timescales as well as the recency of a comprehensive instrumental record, it is difficult to detect or provide evidence for long-term, site-specific trends in ocean temperature. Here we analyze five in situ datasets from Florida Keys coral reef habitats, including historic measurements taken by lighthouse keepers, to provide three independent lines of evidence supporting approximately 0.8 °C of warming in sea surface temperature (SST) over the last century. Results indicate that the warming observed in the records between 1878 and 2012 can be fully accounted for by the warming observed in recent decades (from 1975 to 2007), documented using in situ thermographs on a mid-shore patch reef. The magnitude of warming revealed here is similar to that found in other SST datasets from the region and to that observed in global mean surface temperature. The geologic context and significance of recent ocean warming to coral growth and population dynamics are discussed, as is the future prognosis for the Florida reef tract.

  8. The Change in Oceanic O2 Inventory Associated with Recent Global Warming

    Science.gov (United States)

    Keeling, Ralph; Garcia, Hernan

    2002-01-01

    Oceans general circulation models predict that global warming may cause a decrease in the oceanic O2 inventory and an associated O2 outgassing. An independent argument is presented here in support of this prediction based on observational evidence of the ocean's biogeochemical response to natural warming. On time scales from seasonal to centennial, natural O2 flux/heat flux ratios are shown to occur in a range of 2 to 10 nmol O2 per Joule of warming, with larger ratios typically occurring at higher latitudes and over longer time scales. The ratios are several times larger than would be expected solely from the effect of heating on the O2 solubility, indicating that most of the O2 exchange is biologically mediated through links between heating and stratification. The change in oceanic O2 inventory through the 1990's is estimated to be 0.3 - 0.4 x 10(exp 14) mol O2 per year based on scaling the observed anomalous long-term ocean warming by natural O2 flux/heating ratios and allowing for uncertainty due to decadal variability. Implications are discussed for carbon budgets based on observed changes in atmospheric O2/N2 ratio and based on observed changes in ocean dissolved inorganic carbon.

  9. Variations of polycyclic aromatic hydrocarbons in ambient air during haze and non-haze episodes in warm seasons in Hangzhou, China.

    Science.gov (United States)

    Lu, Hao; Wang, Shengsheng; Wu, Zuliang; Yao, Shuiliang; Han, Jingyi; Tang, Xiujuan; Jiang, Boqiong

    2017-01-01

    To investigate the characteristics of polycyclic aromatic hydrocarbons (PAHs) during haze episodes in warm seasons, daily PM 2.5 and gaseous samples were collected from March to September 2015 in Hangzhou, China. Daily samples were further divided into four groups by the definition of haze according to visibility and relative humidity (RH), including non-haze (visibility, >10 km), light haze (visibility, 8-10 km, RH <90 %), medium haze (visibility, 5-8 km, RH <90 %), and heavy haze (visibility, <5 km, RH <90 %). Significantly higher concentrations of PM 2.5 -bound PAHs were found in haze days, but the mean PM 2.5 -bound PAH concentrations obviously decreased with the aggravation of haze pollution from light to heavy. The gas/particle partitioning coefficients of PAHs decreased from light-haze to heavy-haze episodes, which indicated that PM 2.5 -bound PAHs were restricted to adhere to the particulate phase with the aggravation of haze pollution. Absorption was considered the main mechanism of gas/particle partitioning of PAHs from gaseous to particulate phase. Analysis of air mass transport indicated that the PM 2.5 -bound PAH pollution in haze days was largely from regional sources but also significantly affected by long-range air mass transport. The inhalation cancer risk associated with PAHs exceeded the acceptable risk level markedly in both haze and non-haze days.

  10. Insect-induced tree mortality of boreal forests in eastern Canada under a changing climate.

    Science.gov (United States)

    Zhang, Xiongqing; Lei, Yuancai; Ma, Zhihai; Kneeshaw, Dan; Peng, Changhui

    2014-06-01

    Forest insects are major disturbances that induce tree mortality in eastern coniferous (or fir-spruce) forests in eastern North America. The spruce budworm (SBW) (Choristoneura fumiferana [Clemens]) is the most devastating insect causing tree mortality. However, the relative importance of insect-caused mortality versus tree mortality caused by other agents and how this relationship will change with climate change is not known. Based on permanent sample plots across eastern Canada, we combined a logistic model with a negative model to estimate tree mortality. The results showed that tree mortality increased mainly due to forest insects. The mean difference in annual tree mortality between plots disturbed by insects and those without insect disturbance was 0.0680 per year (P eastern Canada but that tree mortality induced by insect outbreaks will decrease in eastern Canada under warming climate.

  11. Autumn Weather and Winter Increase in Cerebrovascular Disease Mortality

    LENUS (Irish Health Repository)

    McDonagh, R

    2016-11-01

    Mortality from cerebrovascular disease increases in winter but the cause is unclear. Ireland’s oceanic climate means that it infrequently experiences extremes of weather. We examined how weather patterns relate to stroke mortality in Ireland. Seasonal data for Sunshine (% of average), Rainfall (% of average) and Temperature (degrees Celsius above average) were collected for autumn (September-November) and winter (December-February) using official Irish Meteorological Office data. National cerebrovascular mortality data was obtained from Quarterly Vital Statistics. Excess winter deaths were calculated by subtracting (nadir) 3rd quarter mortality data from subsequent 1st quarter data. Data for 12 years were analysed, 2002-2014. Mean winter mortality excess was 24.7%. Winter mortality correlated with temperature (r=.60, p=0.04). Rise in winter mortality correlated strongly with the weather in the preceding autumn (Rainfall: r=-0.19 p=0.53, Temperature: r=-0.60, p=0.03, Sunshine, r=0.58, p=0.04). Winter cerebrovascular disease mortality appears higher following cool, sunny autum

  12. El Niño Southern Oscillation (ENSO and global warming

    Directory of Open Access Journals (Sweden)

    B. Nyenzi

    2006-01-01

    Full Text Available It is widely accepted by the international scientific community that human activities have increased atmospheric concentrations of greenhouse gases (GHG and aerosols since the pre-industrial era. This increase has contributed to most of the warming (0.6±0.2°C observed over the 20th century, land areas warming more than the oceans, with the 1990s very likely to be the warmest decade of the 20th century (IPCC, 2001. How this warming influences the occurrence, severity and frequency of ENSO episodes remains highly uncertain. The IPCC (2001 assessment of the scientific literature found insufficient evidence to suggest any direct attribution between increase in ENSO events that occurred in the last 20 to 30 years of the 20th century and global warming (IPCC, 2001. However, assessments carried out since then (e.g. IPCC Fourth Assessment Report (AR4, in preparations suggest El Niño events have become more frequent, persistent and intense during the last 20 to 30 years compared to the previous 100 years. Attribution to global warming, however, remains highly uncertain. Efforts to simulate and model past, present and future behaviour of ENSO under a warming world due to enhanced GHG concentrations produce conflicting results. Since substantial internally-generated variability of ENSO behaviour on multi-decadal to century timescales occurs in long, unforced atmospheric-oceanic general circulation model (AOGCM simulations, the attribution of past and future changes in ENSO amplitude and frequency to external forcing like GHG concentrations cannot be made with certainty. Such attribution would require extensive use of ensemble climate experiments or long experiments with stabilised GHG forcing. Although there are now better ENSO simulations in AOGCM, further model improvements are needed to simulate a more realistic Pacific climatology and seasonal cycle of the key modes influencing the climate of the region, as well as more realistic ENSO variability

  13. Strong Delayed Interactive Effects of Metal Exposure and Warming: Latitude-Dependent Synergisms Persist Across Metamorphosis.

    Science.gov (United States)

    Debecker, Sara; Dinh, Khuong V; Stoks, Robby

    2017-02-21

    As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species' ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and low-latitude populations. By integrating these mechanisms into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies. These results highlight that a more complete life-cycle approach that incorporates the possibility of delayed interactions between contaminants and warming in a geographical context is crucial for a more realistic risk assessment in a warming world.

  14. Effects of short term and long term soil warming on ecosystem phenology of a sub-arctic grassland: an NDVI-based approach

    Science.gov (United States)

    Leblans, Niki; Sigurdsson, Bjarni D.; Janssens, Ivan A.

    2014-05-01

    Phenology has been defined as the study of the timing of recurring biological events and the causes of their timing with regard to abiotic and biotic factors. Ecosystem phenology, including the onset of the growing season and its senescence in autumn, plays an important role in the carbon, water and energy exchange between biosphere and atmosphere at higher latitudes. Factors that influence ecosystem phenology can therefore induce important climate-controlling feedback mechanisms. Global surface temperatures have been predicted to increase in the coming decades. Hence, a better understanding of the effect of temperature on ecosystem phenology is essential. Natural geothermal soil temperature gradients in Iceland offer a unique opportunity to study the soil temperature (Ts) dependence of ecosystem phenology and distinguish short-term (transient) warming effects (in recently established Ts gradients) from long-term (permanent) effects (in centuries-old Ts gradients). This research was performed in the framework of an international research project (ForHot; www.forhot.is). ForHot includes two natural grassland areas with gradients in Ts, dominated by Festuca sp., Agrostis sp.. The first warmed area was created in 2008, when an earthquake in S-Iceland caused geothermal systems to be shifted to previously cold soils. The second area is located about 3 km away from this newly warmed grassland. For this area, there are proofs that the natural soil warming has been continuous for at least 300 year. In the present study we focus on Ts elevation gradients of +0 to +10°C. The experiment consists of five transects with five temperature levels (+0,+1,+3,+5 and +10°C) in the two aforementioned grassland ecosystems (n=25 in each grassland). From April until November 2013, weekly measurements of the normalized difference vegetation index (NDVI) were taken. In the short-term warmed grassland, the greening of the vegetation was 36 days advanced at +10°C Ts and the date of 50

  15. Recent global-warming hiatus tied to equatorial Pacific surface cooling.

    Science.gov (United States)

    Kosaka, Yu; Xie, Shang-Ping

    2013-09-19

    Despite the continued increase in atmospheric greenhouse gas concentrations, the annual-mean global temperature has not risen in the twenty-first century, challenging the prevailing view that anthropogenic forcing causes climate warming. Various mechanisms have been proposed for this hiatus in global warming, but their relative importance has not been quantified, hampering observational estimates of climate sensitivity. Here we show that accounting for recent cooling in the eastern equatorial Pacific reconciles climate simulations and observations. We present a novel method of uncovering mechanisms for global temperature change by prescribing, in addition to radiative forcing, the observed history of sea surface temperature over the central to eastern tropical Pacific in a climate model. Although the surface temperature prescription is limited to only 8.2% of the global surface, our model reproduces the annual-mean global temperature remarkably well with correlation coefficient r = 0.97 for 1970-2012 (which includes the current hiatus and a period of accelerated global warming). Moreover, our simulation captures major seasonal and regional characteristics of the hiatus, including the intensified Walker circulation, the winter cooling in northwestern North America and the prolonged drought in the southern USA. Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Niña-like decadal cooling. Although similar decadal hiatus events may occur in the future, the multi-decadal warming trend is very likely to continue with greenhouse gas increase.

  16. ECONOMIC IMPACT OF CALF MORTALITY ON DAIRY FARMS IN KUWAIT

    Directory of Open Access Journals (Sweden)

    M. A. RAZZAQUE, M. BEDAIR, S. ABBAS AND T. AL-MUTAWA

    2009-07-01

    Full Text Available Objective of this study was to investigate the economic impact of mortality of pre-weaned calves on dairy cattle enterprise in Kuwait. Cost/benefit analysis model was applied to two different situations: in the first situation, a baseline scenario, field survey data without intervention using 1,280 newborn calves was used in first calving season. In the second situation, the intervention scenario (improved management, 665 newborn calves were used in second calving season during the following year. Calving seasons extended for 7 months from September to March. Calf performance studies were conducted from birth to weaning. Economic model was constructed on Microsoft Excel and used to evaluate the impact of calf mortality on calf enterprise. Results showed that gross margins increased from 13 to 35% as a result of implementation of intervention measures during the second calving season over baseline scenario. A significant correlation between increased veterinary expenses and an increase in revenues (r2 = 0.65, P<0.05 was observed. If the intervention measures such as colostrum feeding, nutrition and hygiene had not been implemented, the farms would have lose income from 12 to 51% of the gross revenues. Net income was influenced by costs of feeds, veterinary services and laborers. Discounted cash flow studies on a whole farm basis revealed that the impact of interventions was small (0-3%. Calf mortality could not be isolated from whole farm for assessing its impact on dairy farm economics. Economic studies demonstrated the cost/benefits of using the improved techniques of calf rearing.

  17. Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005.

    Science.gov (United States)

    Eakin, C Mark; Morgan, Jessica A; Heron, Scott F; Smith, Tyler B; Liu, Gang; Alvarez-Filip, Lorenzo; Baca, Bart; Bartels, Erich; Bastidas, Carolina; Bouchon, Claude; Brandt, Marilyn; Bruckner, Andrew W; Bunkley-Williams, Lucy; Cameron, Andrew; Causey, Billy D; Chiappone, Mark; Christensen, Tyler R L; Crabbe, M James C; Day, Owen; de la Guardia, Elena; Díaz-Pulido, Guillermo; DiResta, Daniel; Gil-Agudelo, Diego L; Gilliam, David S; Ginsburg, Robert N; Gore, Shannon; Guzmán, Héctor M; Hendee, James C; Hernández-Delgado, Edwin A; Husain, Ellen; Jeffrey, Christopher F G; Jones, Ross J; Jordán-Dahlgren, Eric; Kaufman, Les S; Kline, David I; Kramer, Philip A; Lang, Judith C; Lirman, Diego; Mallela, Jennie; Manfrino, Carrie; Maréchal, Jean-Philippe; Marks, Ken; Mihaly, Jennifer; Miller, W Jeff; Mueller, Erich M; Muller, Erinn M; Orozco Toro, Carlos A; Oxenford, Hazel A; Ponce-Taylor, Daniel; Quinn, Norman; Ritchie, Kim B; Rodríguez, Sebastián; Ramírez, Alberto Rodríguez; Romano, Sandra; Samhouri, Jameal F; Sánchez, Juan A; Schmahl, George P; Shank, Burton V; Skirving, William J; Steiner, Sascha C C; Villamizar, Estrella; Walsh, Sheila M; Walter, Cory; Weil, Ernesto; Williams, Ernest H; Roberson, Kimberly Woody; Yusuf, Yusri

    2010-11-15

    The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

  18. Large Plankton Enhance Heterotrophy Under Experimental Warming in a Temperate Coastal Ecosystem

    KAUST Repository

    Huete-Stauffer, Tamara Megan

    2017-12-15

    Microbes are key players in oceanic carbon fluxes. Temperate ecosystems are seasonally variable and thus suitable for testing the effect of warming on microbial carbon fluxes at contrasting oceanographic conditions. In four experiments conducted in February, April, August and October 2013 in coastal NE Atlantic waters, we monitored microbial plankton stocks and daily rates of primary production, bacterial heterotrophic production and respiration at in situ temperature and at 2 and 4°C over ambient values during 4-day incubations. Ambient total primary production (TPP) exceeded total community respiration (< 200 µm, TR) in winter and fall but not in spring and summer. The bacterial contribution to ecosystem carbon fluxes was low, with bacterial production representing on average 6.9 ± 3.2% of TPP and bacterial respiration (between 0.8 and 0.2 µm) contributing on average 35 ± 7% to TR. Warming did not result in a uniform increase in the variables considered, and most significant effects were found only for the 4°C increase. In the summer and fall experiments, under warm and nutrient-deficient conditions, the net TPP/TR ratio decreased by 39 and 34% in the 4°C treatment, mainly due to the increase in respiration of large organisms rather than bacteria. Our results indicate that the interaction of temperature and substrate availability in determining microbial carbon fluxes has a strong seasonal component in temperate planktonic ecosystems, with temperature having a more pronounced effect and generating a shift toward net heterotrophy under more oligotrophic conditions as found in summer and early fall.

  19. Investigate the plant biomass response to climate warming in permafrost ecosystem using matrix-based data assimilation

    Science.gov (United States)

    Lu, X.; Du, Z.; Schuur, E.; Luo, Y.

    2017-12-01

    Permafrost is one of the most vulnerable regions on the earth with over 40% world soil C represented in this region. Future climate warming potentially has a great impact on this region. On one hand, rising temperature accelerates permafrost soil thaw and release more C from land. On the other hand, warming may also increase the plant growing season length and therefore negatively feedback to climate change by increasing annual land C uptake. However, whether permafrost vegetation biomass change in response to warming can sequester more C has not been well understood. Manipulated air warming experiments reported that air warming has very limited impacts on grass land productivity and biomass growth in permafrost region [Mauritz et al., 2017]. It is hard to reveal the mechanisms behind the limited air warming response directly from experiment data. We employ a vegetation C cycle matrix model based on Community land model 4.5 (CLM4.5) and data assimilation technique to investigate how much do phenology and physiology processes contribute to the response respectively. Our results indicate phenology contributes the most in response to warming. The shift of vegetation parameter distributions after 2012 indicate vegetation acclimation may explain the modest response in plant biomass to air warming. The results suggest future model development need to take vegetation acclimation more seriously. The novel matrix-based model allows data assimilation to be conducted more efficiently. It provides more functional understanding of the models as well as the mechanism behind experiment data.

  20. Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water stability in an annual grassland

    Energy Technology Data Exchange (ETDEWEB)

    Rillig, M.C.; Wright, S.F.; Shaw, M.R.; Field, C.B.

    2002-04-01

    Despite the importance of arbuscular mycorrhizae to the functioning of terrestrial ecosystems (e.g. nutrient uptake, soil aggregation), and the increasing evidence of global warming, responses of arbuscular mycorrhizal fungi (AMF) to climate warming are poorly understood. In a field experiment using infrared heaters, we found effects of warming on AMF after one growing season in an annual grassland, in the absence of any effects on measured root parameters (weight, length, average diameter). AMF soil hyphal length was increased by over 40% in the warmed plots, accompanied by a strong trend for AMF root colonization increase. In the following year, root weight was again not significantly changed, and AMF root colonization increased significantly in the warmed plots. Concentration of the soil protein glomalin, a glycoprotein produced by AMF hyphae with importance in soil aggregation, was decreased in the warmed plots. Soil aggregate water stability, measured for five diameter size classes, was also decreased significantly. In the following year, soil aggregate weight in two size classes was decreased significantly, but the effect size was very small. These results indicate that ecosystem warming may have stimulated carbon allocation to AMF. Other factors either influenced glomalin decomposition or production, hence influencing the role of these symbionts in soil aggregation. The observed small changes in soil aggregation, if widespread among terrestrial ecosystems, could have important consequences for soil carbon storage and erosion in a warmed climate, especially if there are cumulative effects of warming. (au)

  1. The effects of warming and nitrogen addition on soil nitrogen cycling in a temperate grassland, northeastern China.

    Directory of Open Access Journals (Sweden)

    Lin-Na Ma

    Full Text Available Both climate warming and atmospheric nitrogen (N deposition are predicted to affect soil N cycling in terrestrial biomes over the next century. However, the interactive effects of warming and N deposition on soil N mineralization in temperate grasslands are poorly understood.A field manipulation experiment was conducted to examine the effects of warming and N addition on soil N cycling in a temperate grassland of northeastern China from 2007 to 2009. Soil samples were incubated at a constant temperature and moisture, from samples collected in the field. The results showed that both warming and N addition significantly stimulated soil net N mineralization rate and net nitrification rate. Combined warming and N addition caused an interactive effect on N mineralization, which could be explained by the relative shift of soil microbial community structure because of fungal biomass increase and strong plant uptake of added N due to warming. Irrespective of strong intra- and inter-annual variations in soil N mineralization, the responses of N mineralization to warming and N addition did not change during the three growing seasons, suggesting independence of warming and N responses of N mineralization from precipitation variations in the temperate grassland.Interactions between climate warming and N deposition on soil N cycling were significant. These findings will improve our understanding on the response of soil N cycling to the simultaneous climate change drivers in temperate grassland ecosystem.

  2. A Contribution by Ice Nuclei to Global Warming

    Science.gov (United States)

    Zeng, Xiping; Tao, Wei-Kuo; Zhang, Minghua; Hou, Arthur Y.; Xie, Shaocheng; Lang, Stephen; Li, Xiaowen; Starr, David O.; Li, Xiaofan

    2009-01-01

    Ice nuclei (IN) significantly affect clouds via supercooled droplets, that in turn modulate atmospheric radiation and thus climate change. Since the IN effect is relatively strong in stratiform clouds but weak in convective ones, the overall effect depends on the ratio of stratiform to convective cloud amount. In this paper, 10 years of TRMM (Tropical Rainfall Measuring Mission) satellite data are analyzed to confirm that stratiform precipitation fraction increases with increasing latitude, which implies that the IN effect is stronger at higher latitudes. To quantitatively evaluate the IN effect versus latitude, large-scale forcing data from ten field campaigns are used to drive a CRM (cloud-resolving model) to generate longterm cloud simulations. As revealed in the simulations, the increase in the net downward radiative flux at the TOA (top of the atmosphere) from doubling the current IN concentrations is larger at higher latitude, which is attributed to the meridional tendency in the stratiform precipitation fraction. Surface warming from doubling the IN concentrations, based on the radiative balance of the globe, is compared with that from anthropogenic COZ . It is found that the former effect is stronger than the latter in middle and high latitudes but not in the Tropics. With regard to the impact of IN on global warming, there are two factors to consider: the radiative effect from increasing the IN concentration and the increase in IN concentration itself. The former relies on cloud ensembles and thus varies mainly with latitude. In contrast, the latter relies on IN sources (e.g., the land surface distribution) and thus varies not only with latitude but also longitude. Global desertification and industrialization provide clues on the geographic variation of the increase in IN concentration since pre-industrial times. Thus, their effect on global warming can be inferred and then be compared with observations. A general match in geographic and seasonal

  3. Global warming

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Canada's Green Plan strategy for dealing with global warming is being implemented as a multidepartmental partnership involving all Canadians and the international community. Many of the elements of this strategy are built on an existing base of activities predating the Green Plan. Elements of the strategy include programs to limit emissions of greenhouse gases, such as initiatives to encourage more energy-efficient practices and development of alternate fuel sources; studies and policy developments to help Canadians prepare and adapt to climate change; research on the global warming phenomenon; and stimulation of international action on global warming, including obligations arising out of the Framework Convention on Climate Change. All the program elements have been approved, funded, and announced. Major achievements to date are summarized, including improvements in the Energy Efficiency Act, studies on the socioeconomic impacts of global warming, and participation in monitoring networks. Milestones associated with the remaining global warming initiatives are listed

  4. Responses of soil CO2 fluxes to short-term experimental warming in alpine steppe ecosystem, Northern Tibet.

    Science.gov (United States)

    Lu, Xuyang; Fan, Jihui; Yan, Yan; Wang, Xiaodan

    2013-01-01

    Soil carbon dioxide (CO2) emission is one of the largest fluxes in the global carbon cycle. Therefore small changes in the size of this flux can have a large effect on atmospheric CO2 concentrations and potentially constitute a powerful positive feedback to the climate system. Soil CO2 fluxes in the alpine steppe ecosystem of Northern Tibet and their responses to short-term experimental warming were investigated during the growing season in 2011. The results showed that the total soil CO2 emission fluxes during the entire growing season were 55.82 and 104.31 g C m(-2) for the control and warming plots, respectively. Thus, the soil CO2 emission fluxes increased 86.86% with the air temperature increasing 3.74°C. Moreover, the temperature sensitivity coefficient (Q 10) of the control and warming plots were 2.10 and 1.41, respectively. The soil temperature and soil moisture could partially explain the temporal variations of soil CO2 fluxes. The relationship between the temporal variation of soil CO2 fluxes and the soil temperature can be described by exponential equation. These results suggest that warming significantly promoted soil CO2 emission in the alpine steppe ecosystem of Northern Tibet and indicate that this alpine ecosystem is very vulnerable to climate change. In addition, soil temperature and soil moisture are the key factors that controls soil organic matter decomposition and soil CO2 emission, but temperature sensitivity significantly decreases due to the rise in temperature.

  5. Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming

    NARCIS (Netherlands)

    Sterck, Frank; Anten, Niels P.R.; Schieving, Feike; Zuidema, Pieter A.

    2016-01-01

    There is a heated debate about the effect of global change on tropical forests. Many scientists predict large-scale tree mortality while others point to mitigating roles of CO2 fertilization and – the notoriously unknown – physiological trait acclimation of trees. In this opinion article we provided

  6. Nonstructural leaf carbohydrate dynamics of Pinus edulis during drought-induced tree mortality reveal role for carbon metabolism in mortality mechanism.

    Science.gov (United States)

    Adams, Henry D; Germino, Matthew J; Breshears, David D; Barron-Gafford, Greg A; Guardiola-Claramonte, Maite; Zou, Chris B; Huxman, Travis E

    2013-03-01

    Vegetation change is expected with global climate change, potentially altering ecosystem function and climate feedbacks. However, causes of plant mortality, which are central to vegetation change, are understudied, and physiological mechanisms remain unclear, particularly the roles of carbon metabolism and xylem function. We report analysis of foliar nonstructural carbohydrates (NSCs) and associated physiology from a previous experiment where earlier drought-induced mortality of Pinus edulis at elevated temperatures was associated with greater cumulative respiration. Here, we predicted faster NSC decline for warmed trees than for ambient-temperature trees. Foliar NSC in droughted trees declined by 30% through mortality and was lower than in watered controls. NSC decline resulted primarily from decreased sugar concentrations. Starch initially declined, and then increased above pre-drought concentrations before mortality. Although temperature did not affect NSC and sugar, starch concentrations ceased declining and increased earlier with higher temperatures. Reduced foliar NSC during lethal drought indicates a carbon metabolism role in mortality mechanism. Although carbohydrates were not completely exhausted at mortality, temperature differences in starch accumulation timing suggest that carbon metabolism changes are associated with time to death. Drought mortality appears to be related to temperature-dependent carbon dynamics concurrent with increasing hydraulic stress in P. edulis and potentially other similar species. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  7. Contrasting effects of summer and winter warming on body mass explain population dynamics in a food-limited Arctic herbivore.

    Science.gov (United States)

    Albon, Steve D; Irvine, R Justin; Halvorsen, Odd; Langvatn, Rolf; Loe, Leif E; Ropstad, Erik; Veiberg, Vebjørn; van der Wal, René; Bjørkvoll, Eirin M; Duff, Elizabeth I; Hansen, Brage B; Lee, Aline M; Tveraa, Torkild; Stien, Audun

    2017-04-01

    The cumulative effects of climate warming on herbivore vital rates and population dynamics are hard to predict, given that the expected effects differ between seasons. In the Arctic, warmer summers enhance plant growth which should lead to heavier and more fertile individuals in the autumn. Conversely, warm spells in winter with rainfall (rain-on-snow) can cause 'icing', restricting access to forage, resulting in starvation, lower survival and fecundity. As body condition is a 'barometer' of energy demands relative to energy intake, we explored the causes and consequences of variation in body mass of wild female Svalbard reindeer (Rangifer tarandus platyrhynchus) from 1994 to 2015, a period of marked climate warming. Late winter (April) body mass explained 88% of the between-year variation in population growth rate, because it strongly influenced reproductive loss, and hence subsequent fecundity (92%), as well as survival (94%) and recruitment (93%). Autumn (October) body mass affected ovulation rates but did not affect fecundity. April body mass showed no long-term trend (coefficient of variation, CV = 8.8%) and was higher following warm autumn (October) weather, reflecting delays in winter onset, but most strongly, and negatively, related to 'rain-on-snow' events. October body mass (CV = 2.5%) increased over the study due to higher plant productivity in the increasingly warm summers. Density-dependent mass change suggested competition for resources in both winter and summer but was less pronounced in recent years, despite an increasing population size. While continued climate warming is expected to increase the carrying capacity of the high Arctic tundra, it is also likely to cause more frequent icing events. Our analyses suggest that these contrasting effects may cause larger seasonal fluctuations in body mass and vital rates. Overall our findings provide an important 'missing' mechanistic link in the current understanding of the population biology of a

  8. A shorter snowfall season associated with higher air temperatures over northern Eurasia

    International Nuclear Information System (INIS)

    Ye Hengchun; Cohen, Judah

    2013-01-01

    The temperature sensitivity of the snowfall season (start, end, duration) over northern Eurasia (the former USSR) is analyzed from synoptic records of 547 stations from 1966 to 2000. The results find significant correlations between temperature and snowfall season at approximately 56% of stations (61% for the starting date and 56% for the ending date) with a mean snowfall season duration temperature sensitivity of −6.2 days °C −1 split over the start (2.8 days) and end periods (−3.4 days). Temperature sensitivity was observed to increase with stations’ mean seasonal air temperature, with the strongest relationships at locations of around 6 °C temperature. This implies that increasing air temperature in fall and spring will delay the onset and hasten the end of snowfall events, and reduces the snowfall season length by 6.2 days for each degree of increase. This study also clarifies that the increasing trend in snowfall season length during 1936/37–1994 over northern European Russia and central Siberia revealed in an earlier study is unlikely to be associated with warming in spring and fall seasons. (letter)

  9. Distribution, survivorship and mortality sources in immature stages of the neotropical leaf miner Pachyschelus coeruleipennis Kerremans (Coleoptera: Buprestidae

    Directory of Open Access Journals (Sweden)

    QUEIROZ J. M.

    2002-01-01

    Full Text Available Distribution, sources of mortality, and survivorship of immatures was investigated during the reproductive season of the neotropical buprestid leaf miner, Pachyschelus coeruleipennis, that burrows in leaves of Croton floribundus (Euphorbiaceae in SE, Brazil. Immature distribution was investigated by a random sample of 120 shrubs of C. floribundus growing along forest edges. Marked leaves were followed to recorded sources of mortality and survivorship of immature stages. Females lay their eggs preferentially in the young leaves of the host plant, with mines and pupal cells having been found on the middle part of plants. Densities of eggs, active mines, and pupal cells were, respectively, 25 ± 2, 6 ± 1, and 1 ± 0.3 per 100 leaves. Predators and parasitoids accounted for the majority of losses in the immature P. coeruleipennis population. Mortality was 3 times lower in the egg stage than in the last larval instar. Predation rate was greater than parasitism but the latter increased much more during the development of immatures. Survivorship and sources of mortality were different between early and late season sample of leaf-miner immatures. Parasitism rate was greater in the late-season whereas predation was greater in early-season samples. These results are compared with mortality patterns described for other buprestid leaf miners in temperate and tropical regions.

  10. Influenza vaccine coverage, influenza-associated morbidity and all-cause mortality in Catalonia (Spain).

    Science.gov (United States)

    Muñoz, M Pilar; Soldevila, Núria; Martínez, Anna; Carmona, Glòria; Batalla, Joan; Acosta, Lesly M; Domínguez, Angela

    2011-07-12

    The objective of this work was to study the behaviour of influenza with respect to morbidity and all-cause mortality in Catalonia, and their association with influenza vaccination coverage. The study was carried out over 13 influenza seasons, from epidemiological week 40 of 1994 to week 20 of 2007, and included confirmed cases of influenza and all-cause mortality. Two generalized linear models were fitted: influenza-associated morbidity was modelled by Poisson regression and all-cause mortality by negative binomial regression. The seasonal component was modelled with the periodic function formed by the sum of the sinus and cosines. Expected influenza mortality during periods of influenza virus circulation was estimated by Poisson regression and its confidence intervals using the Bootstrap approach. Vaccination coverage was associated with a reduction in influenza-associated morbidity (pcase of influenza-associated morbidity, an increase of 5% in vaccination coverage represented a reduction of 3% in the incidence rate of influenza. There was a positive association between influenza-associated morbidity and all-cause mortality. Excess mortality attributable to influenza epidemics was estimated as 34.4 (95% CI: 28.4-40.8) weekly deaths. In conclusion, all-cause mortality is a good indicator of influenza surveillance and vaccination coverage is associated with a reduction in influenza-associated morbidity but not with all-cause mortality. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Seasonal ozone uptake by a warm-temperate mixed deciduous and evergreen broadleaf forest in western Japan estimated by the Penman–Monteith approach combined with a photosynthesis-dependent stomatal model

    International Nuclear Information System (INIS)

    Kitao, Mitsutoshi; Komatsu, Masabumi; Hoshika, Yasutomo; Yazaki, Kenichi; Yoshimura, Kenichi; Fujii, Saori; Miyama, Takafumi; Kominami, Yuji

    2014-01-01

    Canopy-level stomatal conductance over a warm-temperate mixed deciduous and evergreen broadleaf forest in Japan was estimated by the Penman–Monteith approach, as compensated by a semi-empirical photosynthesis-dependent stomatal model, where photosynthesis, relative humidity, and CO 2 concentration were assumed to regulate stomatal conductance. This approach, using eddy covariance data and routine meteorological observations at a flux tower site, permits the continuous estimation of canopy-level O 3 uptake, even when the Penman–Monteith approach is unavailable (i.e. in case of direct evaporation from soil or wet leaves). Distortion was observed between the AOT40 exposure index and O 3 uptake through stomata, as AOT40 peaked in April, but with O 3 uptake occurring in July. Thus, leaf pre-maturation in the predominant deciduous broadleaf tree species (Quercus serrata) might suppress O 3 uptake in springtime, even when the highest O 3 concentrations were observed. -- Highlights: • We estimate canopy-level O 3 uptake in a warm-temperate mixed forest in Japan. • The Penman–Monteith approach is compensated by a photosynthesis-dependent model. • Stomatal conductance can be estimated, even in a partly-opened or wet canopy. • The estimated O 3 dose peaks in summer though O 3 exposure peaks in spring. -- Estimation of seasonal O 3 uptake over a mixed-temperate forest compensated by a photosynthesis-dependent stomatal model

  12. Drought-associated tree mortality: Global patterns and insights from tree-ring studies in the southwestern U.S.A

    Science.gov (United States)

    Macalady, Alison Kelly

    changes correctly classified the status of ˜70% of trees. Climate responses and competitive interactions partly explained growth differences between dying and surviving trees, with muted response to wet/cool conditions and enhanced sensitivity to competition from congeners linked to growth patterns associated with death. Discrimination and validation of models of mortality risk varied widely across sites and drought events, indicating shifting growth-mortality relationships and differences in mortality processes across space and time (Appendix B). Pre-formed defense anatomy is strongly associated with pinon survivorship over a range of sites and stand conditions. Models of mortality risk that account for both growth and resin duct attributes had ≈10 19 more support than models that contained only growth. The greatest improvement in classification was among trees from the 2000s drought, suggesting an enhanced role for tree defense allocation and/or bark beetle activity during recent warm versus historic cool drought. Accounting for defense characteristics and growth-defense allocation is likely to be important for improving representation of drought-associated mortality (Appendix C). Pinon resin duct chronologies contain climate responses that are coherent and distinct from those of radial growth. Growth responds positively and strongly to previous fall and current winter precipitation, and negatively to late spring and early summer temperature. A relatively equal positive resin duct response to winter precipitation and positive response to mid-to-late summer drought suggests that changes in climate will affect tree defense anatomy in complex ways, with the outcome determined by seasonal changes in precipitation and temperature (Appendix D).

  13. Modelling seasonal effects of temperature and precipitation on honey bee winter mortality in a temperate climate.

    Science.gov (United States)

    Switanek, Matthew; Crailsheim, Karl; Truhetz, Heimo; Brodschneider, Robert

    2017-02-01

    Insect pollinators are essential to global food production. For this reason, it is alarming that honey bee (Apis mellifera) populations across the world have recently seen increased rates of mortality. These changes in colony mortality are often ascribed to one or more factors including parasites, diseases, pesticides, nutrition, habitat dynamics, weather and/or climate. However, the effect of climate on colony mortality has never been demonstrated. Therefore, in this study, we focus on longer-term weather conditions and/or climate's influence on honey bee winter mortality rates across Austria. Statistical correlations between monthly climate variables and winter mortality rates were investigated. Our results indicate that warmer and drier weather conditions in the preceding year were accompanied by increased winter mortality. We subsequently built a statistical model to predict colony mortality using temperature and precipitation data as predictors. Our model reduces the mean absolute error between predicted and observed colony mortalities by 9% and is statistically significant at the 99.9% confidence level. This is the first study to show clear evidence of a link between climate variability and honey bee winter mortality. Copyright © 2016 British Geological Survey, NERC. Published by Elsevier B.V. All rights reserved.

  14. Adaptation to seasonality and the winter freeze

    Directory of Open Access Journals (Sweden)

    Jill Christine Preston

    2013-06-01

    Full Text Available Flowering plants initially diversified during the Mesozoic era at least 140 million years ago in regions of the world where temperate seasonal environments were not encountered. Since then several cooling events resulted in the contraction of warm and wet environments and the establishment of novel temperate zones in both hemispheres. In response, less than half of modern angiosperm families have members that evolved specific adaptations to cold seasonal climates, including cold acclimation, freezing tolerance, endodormancy, and vernalization responsiveness. Despite compelling evidence for multiple independent origins, the level of genetic constraint on the evolution of adaptations to seasonal cold is not well understood. However, the recent increase in molecular genetic studies examining the response of model and crop species to seasonal cold offers new insight into the evolutionary lability of these traits. This insight has major implications for our understanding of complex trait evolution, and the potential role of local adaptation in response to past and future climate change. In this review, we discuss the biochemical, morphological, and developmental basis of adaptations to seasonal cold, and synthesize recent literature on the genetic basis of these traits in a phylogenomic context. We find evidence for multiple genetic links between distinct physiological responses to cold, possibly reinforcing the coordinated expression of these traits. Furthermore, repeated recruitment of the same or similar ancestral pathways suggests that land plants might be somewhat pre-adapted to dealing with temperature stress, perhaps making inducible cold traits relatively easy to evolve.

  15. Lagging adaptation to warming climate in Arabidopsis thaliana.

    Science.gov (United States)

    Wilczek, Amity M; Cooper, Martha D; Korves, Tonia M; Schmitt, Johanna

    2014-06-03

    If climate change outpaces the rate of adaptive evolution within a site, populations previously well adapted to local conditions may decline or disappear, and banked seeds from those populations will be unsuitable for restoring them. However, if such adaptational lag has occurred, immigrants from historically warmer climates will outperform natives and may provide genetic potential for evolutionary rescue. We tested for lagging adaptation to warming climate using banked seeds of the annual weed Arabidopsis thaliana in common garden experiments in four sites across the species' native European range: Valencia, Spain; Norwich, United Kingdom; Halle, Germany; and Oulu, Finland. Genotypes originating from geographic regions near the planting site had high relative fitness in each site, direct evidence for broad-scale geographic adaptation in this model species. However, genotypes originating in sites historically warmer than the planting site had higher average relative fitness than local genotypes in every site, especially at the northern range limit in Finland. This result suggests that local adaptive optima have shifted rapidly with recent warming across the species' native range. Climatic optima also differed among seasonal germination cohorts within the Norwich site, suggesting that populations occurring where summer germination is common may have greater evolutionary potential to persist under future warming. If adaptational lag has occurred over just a few decades in banked seeds of an annual species, it may be an important consideration for managing longer-lived species, as well as for attempts to conserve threatened populations through ex situ preservation.

  16. Climate and tourism in the Black Forest during the warm season.

    Science.gov (United States)

    Endler, Christina; Matzarakis, Andreas

    2011-03-01

    Climate, climate change and tourism all interact. Part of the public discussion about climate change focusses on the tourism sector, with direct and indirect impacts being of equally high relevance. Climate and tourism are closely linked. Thus, climate is a very decisive factor in choices both of destination and of type of journey (active holidays, wellness, and city tours) in the tourism sector. However, whether choices about destinations or types of trip will alter with climate change is difficult to predict. Future climates can be simulated and projected, and the tendencies of climate parameters can be estimated using global and regional climate models. In this paper, the focus is on climate change in the mountainous regions of southwest Germany - the Black Forest. The Black Forest is one of the low mountain ranges where both winter and summer tourism are vulnerable to climate change due to its southern location; the strongest climatic changes are expected in areas covering the south and southwest of Germany. Moreover, as the choice of destination is highly dependent on good weather, a climatic assessment for tourism is essential. Thus, the aim of this study was to estimate climatic changes in mountainous regions during summer, especially for tourism and recreation. The assessment method was based on human-biometeorology as well as tourism-climatologic approaches. Regional climate simulations based on the regional climate model REMO were used for tourism-related climatic analyses. Emission scenarios A1B and B1 were considered for the time period 2021 to 2050, compared to the 30-year base period of 1971-2000, particularly for the warm period of the year, defined here as the months of March-November. In this study, we quantified the frequency, but not the means, of climate parameters. The study results show that global and regional warming is reflected in an increase in annual mean air temperature, especially in autumn. Changes in the spring show a slight negative

  17. Climate, Tree Growth, Forest Drought Stress, and Tree Mortality in Forests of Western North America: Long-Term Patterns and Recent Trends

    Science.gov (United States)

    Allen, C. D.; Williams, P.

    2012-12-01

    Ongoing climate changes are increasingly affecting the world's forests, particularly including high latitude and high elevation coniferous forests. Although forest growth has improved in some regions due to greater growing season length and warmth (perhaps along with increased atmospheric CO2 or N), large growth declines or increased mortality from droughts or hotter temperatures also are being observed. We present and interpret information on regional variation in climate-tree growth relationships and trends, and on patterns and trends of climate-related forest disturbances, from western North America. From 235 tree-ring chronologies in the Southwest US we show that tree-ring growth records from warmer southwestern sites are more sensitive to temperature than tree-ring growth records from cooler southwestern sites. Assessment of 59 tree-ring records from 11 species in the Cascade Mountains of the Pacific Northwest shows that trees growing in cool places respond positively to increased temperature and trees in warm places respond negatively, implying that trees historically not sensitive to temperature may become sensitive as mean temperatures warm. An analysis of 59 white spruce populations in Alaska supports the hypothesis that warming has caused tree growth to lose sensitivity to cold temperatures. Comparing ring widths to temperature during just the coldest 50% of years during the 20th century, tree growth was sensitive to cold temperatures, and this effect was strongest at the coldest sites; whereas during the warmest 50% of years, trees were not at all sensitive to cold temperatures, even at the cold sites. Drought and vapor pressure deficit are among the variables that emerge as being increasingly important to these Alaska boreal forests as mean temperatures rise. Most recently, from 346 tree-ring chronologies in the Southwest US we establish a tree-ring-based Forest Drought Stress Index (FDSI) for the three most widespread conifer species (Pinus edulis

  18. Impact of Environmental Changes and Global Warming on Temperature in Pakistan

    Directory of Open Access Journals (Sweden)

    Ishtiaq Hassan

    2011-01-01

    Full Text Available Environmental changes and global warming have direct impact on human life. Estimation of these changes in various parameters of hydrologic cycle is necessary for future planning and development of a country. In this paper the impact of environmental changes and global warming on temperatures of Pakistan has been studied. The temperature changes in Pakistan have been extracted from simulations made using EdGCM model developed at Columbia University. Simulation study to the end of 21st century is executed using the model for GHG (Greenhouse Gases scenario with doubled_CO2 and scenario of Modern_Predicted SST (Sea Surface Temperature. The model analysis has been carried out for seasonal and annual changes for an average of last 5 years period from 2096-2100. Maps are generated to depict global temperature variations. The study divides Pakistan into five (05 main areas for twenty six (26 stations. A part-plan of globe focusing Pakistan is generated showing the five divisions for twenty six (26 data stations of Pakistan. This part plan is made compatible with grid-box resolution of EdGCM. Eagle-Point Engineering software has been used to generate isohyets of interval (0.5oC for downscaling GCM (Global Climate Model grid data to data stations. The station values of different seasons and annual changes are then compared with the values of base period data to determine changes in temperature. It is observed that impact of global environmental changes on temperature are higher (i.e. there is an increase in annual temperature for double_CO2 experiment at places near the Arabian Sea than areas located away from this sea. It is also observed that the temperature increase will be more in winter than that in other seasons for Pakistan.

  19. Thermal comfort of people in the hot and humid area of China-impacts of season, climate, and thermal history.

    Science.gov (United States)

    Zhang, Y; Chen, H; Wang, J; Meng, Q

    2016-10-01

    We conducted a climate chamber study on the thermal comfort of people in the hot and humid area of China. Sixty subjects from naturally ventilated buildings and buildings with split air conditioners participated in the study, and identical experiments were conducted in a climate chamber in both summer and winter. Psychological and physiological responses were observed over a wide range of conditions, and the impacts of season, climate, and thermal history on human thermal comfort were analyzed. Seasonal and climatic heat acclimatization was confirmed, but they were found to have no significant impacts on human thermal sensation and comfort. The outdoor thermal history was much less important than the indoor thermal history in regard to human thermal sensation, and the indoor thermal history in all seasons of a year played a key role in shaping the subjects' sensations in a wide range of thermal conditions. A warmer indoor thermal history in warm seasons produced a higher neutral temperature, a lower thermal sensitivity, and lower thermal sensations in warm conditions. The comfort and acceptable conditions were identified for people in the hot and humid area of China. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Seasonal prediction of the Leeuwin Current using the POAMA dynamical seasonal forecast model

    Energy Technology Data Exchange (ETDEWEB)

    Hendon, Harry H.; Wang, Guomin [Centre for Australian Weather and Climate Research, Bureau of Meteorology, PO Box 1289, Melbourne (Australia)

    2010-06-15

    The potential for predicting interannual variations of the Leeuwin Current along the west coast of Australia is addressed. The Leeuwin Current flows poleward against the prevailing winds and transports warm-fresh tropical water southward along the coast, which has a great impact on local climate and ecosystems. Variations of the current are tightly tied to El Nino/La Nina (weak during El Nino and strong during La Nina). Skilful seasonal prediction of the Leeuwin Current to 9-month lead time is achieved by empirical downscaling of dynamical coupled model forecasts of El Nino and the associated upper ocean heat content anomalies off the north west coast of Australia from the Australian Bureau of Meteorology Predictive Ocean Atmosphere Model for Australia (POAMA) seasonal forecast system. Prediction of the Leeuwin Current is possible because the heat content fluctuations off the north west coast are the primary driver of interannual annual variations of the current and these heat content variations are tightly tied to the occurrence of El Nino/La Nina. POAMA can skilfully predict both the occurrence of El Nino/La Nina and the subsequent transmission of the heat content anomalies from the Pacific onto the north west coast. (orig.)

  1. American lay conceptions of global warming

    International Nuclear Information System (INIS)

    Kempton, W.

    1990-01-01

    Ethnographic interviews were conducted with Americans from all walks of life in order to understand how ordinary citizens conceptualize global climate change and make value judgments about it. Most informants had heard of the greenhouse effect, but they held fundamental misconceptions that were shared across individuals. Many of these misconceptions derive from the process of fitting a new concept, global warming, into four preexisting categories: stratospheric ozone depletion, plant photosynthesis, tropospheric pollution, and personally-experienced seasonal and geographic temperature variation. Informants readily accepted that human activities could change climate and weather patterns. Indeed, most reported they had already observed changes in weather patterns, some citing space shots or atomic bomb testing as causes. Few informants connected the greenhouse effect to energy or fuel consumption, although the connection was easily understood when explained by the interviewers

  2. Calculation of probability density functions for temperature and precipitation change under global warming

    International Nuclear Information System (INIS)

    Watterson, Ian G.

    2007-01-01

    Full text: he IPCC Fourth Assessment Report (Meehl ef al. 2007) presents multi-model means of the CMIP3 simulations as projections of the global climate change over the 21st century under several SRES emission scenarios. To assess the possible range of change for Australia based on the CMIP3 ensemble, we can follow Whetton etal. (2005) and use the 'pattern scaling' approach, which separates the uncertainty in the global mean warming from that in the local change per degree of warming. This study presents several ways of representing these two factors as probability density functions (PDFs). The beta distribution, a smooth, bounded, function allowing skewness, is found to provide a useful representation of the range of CMIP3 results. A weighting of models based on their skill in simulating seasonal means in the present climate over Australia is included. Dessai ef al. (2005) and others have used Monte-Carlo sampling to recombine such global warming and scaled change factors into values of net change. Here, we use a direct integration of the product across the joint probability space defined by the two PDFs. The result is a cumulative distribution function (CDF) for change, for each variable, location, and season. The median of this distribution provides a best estimate of change, while the 10th and 90th percentiles represent a likely range. The probability of exceeding a specified threshold can also be extracted from the CDF. The presentation focuses on changes in Australian temperature and precipitation at 2070 under the A1B scenario. However, the assumption of linearity behind pattern scaling allows results for different scenarios and times to be simply obtained. In the case of precipitation, which must remain non-negative, a simple modification of the calculations (based on decreases being exponential with warming) is used to avoid unrealistic results. These approaches are currently being used for the new CSIRO/ Bureau of Meteorology climate projections

  3. Evaluating the Effects of Temperature on Mortality in Manila City (Philippines from 2006–2010 Using a Distributed Lag Nonlinear Model

    Directory of Open Access Journals (Sweden)

    Xerxes T. Seposo

    2015-06-01

    Full Text Available The effect of temperature on the risk of mortality has been described in numerous studies of category-specific (e.g., cause-, sex-, age-, and season-specific mortality in temperate and subtropical countries, with consistent findings of U-, V-, and J-shaped exposure-response functions. In this study, we analyzed the relationship between temperature and mortality in Manila City (Philippines, during 2006–2010 to identify the potential susceptible populations. We collected daily all-cause and cause-specific death counts from the Philippine Statistics Authority-National Statistics Office and the meteorological variables were collected from the Philippine Atmospheric Geophysical and Astronomical Services Administration. Temperature-mortality relationships were modeled using Poisson regression combined with distributed lag nonlinear models, and were used to perform cause-, sex-, age-, and season-specific analyses. The minimum mortality temperature was 30 °C, and increased risks of mortality were observed per 1 °C increase among elderly persons (RR: 1.53, 95% CI: 1.31–1.80, women (RR: 1.47, 95% CI: 1.27–1.69, and for respiratory causes of death (RR: 1.52, 95% CI: 1.23–1.88. Seasonal effect modification was found to greatly affect the risks in the lower temperature range. Thus, the temperature-mortality relationship in Manila City exhibited an increased risk of mortality among elderly persons, women, and for respiratory-causes, with inherent effect modification in the season-specific analysis. The findings of this study may facilitate the development of public health policies to reduce the effects of air temperature on mortality, especially for these high-risk groups.

  4. Thirty-Three Years of Ocean Benthic Warming Along the U.S. Northeast Continental Shelf and Slope: Patterns, Drivers, and Ecological Consequences

    Science.gov (United States)

    Kavanaugh, Maria T.; Rheuban, Jennie E.; Luis, Kelly M. A.; Doney, Scott C.

    2017-12-01

    The U.S. Northeast Continental Shelf is experiencing rapid warming, with potentially profound consequences to marine ecosystems. While satellites document multiple scales of spatial and temporal variability on the surface, our understanding of the status, trends, and drivers of the benthic environmental change remains limited. We interpolated sparse benthic temperature data along the New England Shelf and upper Slope using a seasonally dynamic, regionally specific multiple linear regression model that merged in situ and remote sensing data. The statistical model predicted nearly 90% of the variability of the data, resulting in a synoptic time series spanning over three decades from 1982 to 2014. Benthic temperatures increased throughout the domain, including in the Gulf of Maine. Rates of benthic warming ranged from 0.1 to 0.4°C per decade, with fastest rates occurring in shallow, nearshore regions and on Georges Bank, the latter exceeding rates observed in the surface. Rates of benthic warming were up to 1.6 times faster in winter than the rest of the year in many regions, with important implications for disease occurrence and energetics of overwintering species. Drivers of warming varied over the domain. In southern New England and the mid-Atlantic shallow Shelf regions, benthic warming was tightly coupled to changes in SST, whereas both regional and basin-scale changes in ocean circulation affect temperatures in the Gulf of Maine, the Continental Shelf, and Georges Banks. These results highlight data gaps, the current feasibility of prediction from remotely sensed variables, and the need for improved understanding on how climate may affect seasonally specific ecological processes.

  5. Unexpected Impacts of Global warming on Extreme Warm Spells

    Science.gov (United States)

    Sardeshmukh, P. D.; Compo, G. P.; McColl, C.; Penland, C.

    2017-12-01

    It is generally presumed that the likelihood of extreme warm spells around the globe has increased, and will continue to increase, due to global warming. However, we find that this is generally not true in three very different types of global observational datasets and uncoupled atmospheric model simulations of the 1959 to 2012 period with prescribed observed global SSTs, sea ice, and radiative forcing changes. While extreme warm spells indeed became more common in many regions, in many other regions their likelihood remained almost the same or even decreased from the first half to the second half of this period. Such regions of unexpected changes covered nearly 40 percent of the globe in both winter and summer. The basic reason for this was a decrease of temperature variability in such regions that offset or even negated the effect of the mean temperature shift on extreme warm spell probabilities. The possibility of such an impact on extreme value probabilities was highlighted in a recent paper by Sardeshmukh, Compo, and Penland (Journal of Climate 2015). The consistency of the changes in extreme warm spell probabilities among the different observational datasets and model simulations examined suggests that they are robust regional aspects of global warming associated with atmospheric circulation changes. This highlights the need for climate models to represent not just the mean regional temperature signals but also the changes in subseasonal temperature variability associated with global warming. However, current climate models (both CMIP3 and CMIP5) generally underestimate the magnitude of the changes in the atmospheric circulation and associated temperature variability. A likely major cause of this is their continuing underestimation of the magnitude of the spatial variation of tropical SST trends. By generating an overly spatially bland tropical SST warming in response to changes in radiative forcing, the models spuriously mute tropically

  6. Effect of nutritional density and season on the performance of young rabbit does before the first mating - doi: 10.4025/actascianimsci.v35i4.19101 Effect of nutritional density and season on the performance of young rabbit does before the first mating - doi: 10.4025/actascianimsci.v35i4.19101

    Directory of Open Access Journals (Sweden)

    Paulo Sergio dos Santos Teixeira

    2013-10-01

    Full Text Available The objective was to evaluate the effect of nutritional density and season on the performance of young rabbit does before the first mating. Forty-eight females from the Botucatu Genetic Group were used in each season (warm or cool, starting at the age of 70 days, housed in groups of four per cage up to 119 days, and reared individually from 120 to 140 days of age. The high-density diet was formulated to contain, on a 90% DM basis, 18.4% CP, 16.5% ADF and 2,500 kcal DE kg-1; whereas the low-density diet was formulated to contain 14.7% CP, 24% ADF and 2,000 kcal DE kg-1. The experiment was conducted according to a 2x2 factorial design (two diets x two seasons with repeated measures (weeks. The high-density diet promoted lower feed intake, higher final weight, and higher daily weight gain, adjusted for constant intake. But these facts alone do not warrant using a high-density diet for growing rabbit does, because it could have a negative impact during the reproductive phase. In the warm season, there was a reduction in feed intake and an improvement in feed efficiency. Along time, however, the mean body weight of does was similar in the two seasons.  The objective was to evaluate the effect of nutritional density and season on the performance of young rabbit does before the first mating. Forty-eight females from the Botucatu Genetic Group were used in each season (warm or cool, starting at the age of 70 days, housed in groups of four per cage up to 119 days, and reared individually from 120 to 140 days of age. The high-density diet was formulated to contain, on a 90% DM basis, 18.4% CP, 16.5% ADF and 2,500 kcal DE kg-1; whereas the low-density diet was formulated to contain 14.7% CP, 24% ADF and 2,000 kcal DE kg-1. The experiment was conducted according to a 2x2 factorial design (two diets x two seasons with repeated measures (weeks. The high-density diet promoted lower feed intake, higher final weight, and higher daily weight gain, adjusted for

  7. Projected changes in prevailing winds for transatlantic migratory birds under global warming.

    Science.gov (United States)

    La Sorte, Frank A; Fink, Daniel

    2017-03-01

    A number of terrestrial bird species that breed in North America cross the Atlantic Ocean during autumn migration when travelling to their non-breeding grounds in the Caribbean or South America. When conducting oceanic crossings, migratory birds tend to associate with mild or supportive winds, whose speed and direction may change under global warming. The implications of these changes for transoceanic migratory bird populations have not been addressed. We used occurrence information from eBird (1950-2015) to estimate the geographical location of population centres at a daily temporal resolution across the annual cycle for 10 transatlantic migratory bird species. We used this information to estimate the location and timing of autumn migration within the transatlantic flyway. We estimated how prevailing winds are projected to change within the transatlantic flyway during this time using daily wind speed anomalies (1996-2005 and 2091-2100) from 29 Atmosphere-Ocean General Circulation Models implemented under CMIP5. Autumn transatlantic migrants have the potential to encounter strong westerly crosswinds early in their transatlantic journey at intermediate and especially high migration altitudes, strong headwinds at low and intermediate migration altitudes within the Caribbean that increase in strength as the season progresses, and weak tailwinds at intermediate and high migration altitudes east of the Caribbean. The CMIP5 simulations suggest that, during this century, the likelihood of autumn transatlantic migrants encountering strong westerly crosswinds will diminish. As global warming progresses, the need for species to compensate or drift under the influence of strong westerly crosswinds during the initial phase of their autumn transatlantic journey may be diminished. Existing strategies that promote headwind avoidance and tailwind assistance will likely remain valid. Thus, climate change may reduce time and energy requirements and the chance of mortality or

  8. Observations from old forests underestimate climate change effects on tree mortality.

    Science.gov (United States)

    Luo, Yong; Chen, Han Y H

    2013-01-01

    Understanding climate change-associated tree mortality is central to linking climate change impacts and forest structure and function. However, whether temporal increases in tree mortality are attributed to climate change or stand developmental processes remains uncertain. Furthermore, interpreting the climate change-associated tree mortality estimated from old forests for regional forests rests on an un-tested assumption that the effects of climate change are the same for young and old forests. Here we disentangle the effects of climate change and stand developmental processes on tree mortality. We show that both climate change and forest development processes influence temporal mortality increases, climate change-associated increases are significantly higher in young than old forests, and higher increases in younger forests are a result of their higher sensitivity to regional warming and drought. We anticipate our analysis to be a starting point for more comprehensive examinations of how forest ecosystems might respond to climate change.

  9. When and where does mortality occur in migratory birds? Direct evidence from long-term satellite tracking of raptors.

    Science.gov (United States)

    Klaassen, Raymond H G; Hake, Mikael; Strandberg, Roine; Koks, Ben J; Trierweiler, Christiane; Exo, Klaus-Michael; Bairlein, Franz; Alerstam, Thomas

    2014-01-01

    Information about when and where animals die is important to understand population regulation. In migratory animals, mortality might occur not only during the stationary periods (e.g. breeding and wintering) but also during the migration seasons. However, the relative importance of population limiting factors during different periods of the year remains poorly understood, and previous studies mainly relied on indirect evidence. Here, we provide direct evidence about when and where migrants die by identifying cases of confirmed and probable deaths in three species of long-distance migratory raptors tracked by satellite telemetry. We show that mortality rate was about six times higher during migration seasons than during stationary periods. However, total mortality was surprisingly similar between periods, which can be explained by the fact that risky migration periods are shorter than safer stationary periods. Nevertheless, more than half of the annual mortality occurred during migration. We also found spatiotemporal patterns in mortality: spring mortality occurred mainly in Africa in association with the crossing of the Sahara desert, while most mortality during autumn took place in Europe. Our results strongly suggest that events during the migration seasons have an important impact on the population dynamics of long-distance migrants. We speculate that mortality during spring migration may account for short-term annual variation in survival and population sizes, while mortality during autumn migration may be more important for long-term population regulation (through density-dependent effects). © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

  10. Using radiative signatures to diagnose the cause of warming during the 2013-2014 Californian drought

    Science.gov (United States)

    Wolf, Sebastian; Yin, Dongqin; Roderick, Michael L.

    2017-10-01

    California recently experienced among the worst droughts of the last century, with exceptional precipitation deficits and co-occurring record high temperatures. The dry conditions caused severe water shortages in one of the economically most important agricultural regions of the US. It has recently been hypothesized that anthropogenic warming is increasing the likelihood of such extreme droughts in California, or more specifically, that warmer temperatures from the enhanced greenhouse effect intensify drought conditions. However, separating the cause and effect is difficult because the dry conditions lead to a reduction in evaporative cooling that contributes to the warming. Here we investigate and compare the forcing of long-term greenhouse-induced warming with the short-term warming during the 2013-2014 Californian drought. We use the concept of radiative signatures to investigate the source of the radiative perturbation during the drought, relate the signatures to expected changes due to anthropogenic warming, and assess the cause of warming based on observed changes in the surface energy balance compared to the period 2001-2012. We found that the recent meteorological drought based on precipitation deficits was characterised by an increase in incoming shortwave radiation coupled with a decline in incoming longwave radiation, which contributed to record warm temperatures. In contrast, climate models project that anthropogenic warming is accompanied by little change in incoming shortwave but a large increase in incoming longwave radiation. The warming during the drought was associated with increased incoming shortwave radiation in combination with reduced evaporative cooling from water deficits, which enhanced surface temperatures and sensible heat transfer to the atmosphere. Our analyses demonstrate that radiative signatures are a powerful tool to differentiate the source of perturbations in the surface energy balance at monthly to seasonal time scales.

  11. Effects of air pollution on infant and children respiratory mortality in four large Latin-American cities

    International Nuclear Information System (INIS)

    Gouveia, Nelson; Junger, Washington Leite; Romieu, Isabelle; Cifuentes, Luis A.; Ponce de Leon, Antonio; Vera, Jeanette; Strappa, Valentina; Hurtado-Díaz, Magali; Miranda-Soberanis, Victor; Rojas-Bracho, Leonora; Carbajal-Arroyo, Luz; Tzintzun-Cervantes, Guadalupe

    2018-01-01

    Objectives: Air pollution is an important public health concern especially for children who are particularly susceptible. Latin America has a large children population, is highly urbanized and levels of pollution are substantially high, making the potential health impact of air pollution quite large. We evaluated the effect of air pollution on children respiratory mortality in four large urban centers: Mexico City, Santiago, Chile, and Sao Paulo and Rio de Janeiro in Brazil. Methods: Generalized Additive Models in Poisson regression was used to fit daily time-series of mortality due to respiratory diseases in infants and children, and levels of PM 10 and O 3 . Single lag and constrained polynomial distributed lag models were explored. Analyses were carried out per cause for each age group and each city. Fixed- and random-effects meta-analysis was conducted in order to combine the city-specific results in a single summary estimate. Results: These cities host nearly 43 million people and pollution levels were above the WHO guidelines. For PM 10 the percentage increase in risk of death due to respiratory diseases in infants in a fixed effect model was 0.47% (0.09–0.85). For respiratory deaths in children 1–5 years old, the increase in risk was 0.58% (0.08–1.08) while a higher effect was observed for lower respiratory infections (LRI) in children 1–14 years old [1.38% (0.91–1.85)]. For O 3 , the only summarized estimate statistically significant was for LRI in infants. Analysis by season showed effects of O 3 in the warm season for respiratory diseases in infants, while negative effects were observed for respiratory and LRI deaths in children. Discussion: We provided comparable mortality impact estimates of air pollutants across these cities and age groups. This information is important because many public policies aimed at preventing the adverse effects of pollution on health consider children as the population group that deserves the highest protection

  12. Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005.

    Directory of Open Access Journals (Sweden)

    C Mark Eakin

    Full Text Available BACKGROUND: The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS: Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE: Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.

  13. Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

    Science.gov (United States)

    Eakin, C. Mark; Morgan, Jessica A.; Heron, Scott F.; Smith, Tyler B.; Liu, Gang; Alvarez-Filip, Lorenzo; Baca, Bart; Bartels, Erich; Bastidas, Carolina; Bouchon, Claude; Brandt, Marilyn; Bruckner, Andrew W.; Bunkley-Williams, Lucy; Cameron, Andrew; Causey, Billy D.; Chiappone, Mark; Christensen, Tyler R. L.; Crabbe, M. James C; Day, Owen; de la Guardia, Elena; Díaz-Pulido, Guillermo; DiResta, Daniel; Gil-Agudelo, Diego L.; Gilliam, David S.; Ginsburg, Robert N.; Gore, Shannon; Guzmán, Héctor M.; Hendee, James C.; Hernández-Delgado, Edwin A.; Husain, Ellen; Jeffrey, Christopher F. G.; Jones, Ross J.; Jordán-Dahlgren, Eric; Kaufman, Les S.; Kline, David I.; Kramer, Philip A.; Lang, Judith C.; Lirman, Diego; Mallela, Jennie; Manfrino, Carrie; Maréchal, Jean-Philippe; Marks, Ken; Mihaly, Jennifer; Miller, W. Jeff; Mueller, Erich M.; Muller, Erinn M.; Orozco Toro, Carlos A.; Oxenford, Hazel A.; Ponce-Taylor, Daniel; Quinn, Norman; Ritchie, Kim B.; Rodríguez, Sebastián; Ramírez, Alberto Rodríguez; Romano, Sandra; Samhouri, Jameal F.; Sánchez, Juan A.; Schmahl, George P.; Shank, Burton V.; Skirving, William J.; Steiner, Sascha C. C.; Villamizar, Estrella; Walsh, Sheila M.; Walter, Cory; Weil, Ernesto; Williams, Ernest H.; Roberson, Kimberly Woody; Yusuf, Yusri

    2010-01-01

    Background The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. Methodology/Principal Findings Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. Conclusions/Significance Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate. PMID:21125021

  14. Regimes of seasonal air-sea interaction and implications for performance of forced simulations

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Renguang [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); Kirtman, Ben P. [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States); George Mason University, School of Computational Sciences, Fairfax, VA (United States)

    2007-09-15

    Sea surface temperature (SST) anomalies can induce anomalous convection through surface evaporation and low-level moisture convergence. This SST forcing of the atmosphere is indicated in a positive local rainfall-SST correlation. Anomalous convection can feedback on SST through cloud-radiation and wind-evaporation effects and wind-induced oceanic mixing and upwelling. These atmospheric feedbacks are reflected in a negative local rainfall-SST tendency correlation. As such, the simultaneous rainfall-SST and rainfall-SST tendency correlations can indicate the nature of local air-sea interactions. Based on the magnitude of simultaneous rainfall-SST and rainfall-SST tendency correlations, the present study identifies three distinct regimes of local air-sea interactions. The relative importance of SST forcing and atmospheric forcing differs in these regimes. In the equatorial central-eastern Pacific and, to a smaller degree, in the western equatorial Indian Ocean, SST forcing dominates throughout the year and the surface heat flux acts mainly as a damping term. In the tropical Indo-western Pacific Ocean regions, SST forcing and atmospheric forcing dominate alternatively in different seasons. Atmospheric forcing dominates in the local warm/rainy season. SST forcing dominates with a positive wind-evaporation feedback during the transition to the cold/dry season. SST forcing also dominates during the transition to the warm/rainy season but with a negative cloud-radiation feedback. The performance of atmospheric general circulation model simulations forced by observed SST is closely linked to the regime of air-sea interaction. The forced simulations have good performance when SST forcing dominates. The performance is low or poor when atmospheric forcing dominates. (orig.)

  15. Spatiotemporal analysis of particulate air pollution and ischemic heart disease mortality in Beijing, China.

    Science.gov (United States)

    Xu, Meimei; Guo, Yuming; Zhang, Yajuan; Westerdahl, Dane; Mo, Yunzheng; Liang, Fengchao; Pan, Xiaochuan

    2014-12-12

    Few studies have used spatially resolved ambient particulate matter with an aerodynamic diameter of <10 μm (PM10) to examine the impact of PM10 on ischemic heart disease (IHD) mortality in China. The aim of our study is to evaluate the short-term effects of PM10 concentrations on IHD mortality by means of spatiotemporal analysis approach. We collected daily data on air pollution, weather conditions and IHD mortality in Beijing, China during 2008 and 2009. Ordinary kriging (OK) was used to interpolate daily PM10 concentrations at the centroid of 287 township-level areas based on 27 monitoring sites covering the whole city. A generalized additive mixed model was used to estimate quantitatively the impact of spatially resolved PM10 on the IHD mortality. The co-effects of the seasons, gender and age were studied in a stratified analysis. Generalized additive model was used to evaluate the effects of averaged PM10 concentration as well. The averaged spatially resolved PM10 concentration at 287 township-level areas was 120.3 ± 78.1 μg/m3. Ambient PM10 concentration was associated with IHD mortality in spatiotemporal analysis and the strongest effects were identified for the 2-day average. A 10 μg/m3 increase in PM10 was associated with an increase of 0.33% (95% confidence intervals: 0.13%, 0.52%) in daily IHD mortality. The effect estimates using spatially resolved PM10 were larger than that using averaged PM10. The seasonal stratification analysis showed that PM10 had the statistically stronger effects on IHD mortality in summer than that in the other seasons. Males and older people demonstrated the larger response to PM10 exposure. Our results suggest that short-term exposure to particulate air pollution is associated with increased IHD mortality. Spatial variation should be considered for assessing the impacts of particulate air pollution on mortality.

  16. Influenza mortality in the United States, 2009 pandemic: burden, timing and age distribution.

    Directory of Open Access Journals (Sweden)

    Ann M Nguyen

    Full Text Available BACKGROUND: In April 2009, the most recent pandemic of influenza A began. We present the first estimates of pandemic mortality based on the newly-released final data on deaths in 2009 and 2010 in the United States. METHODS: We obtained data on influenza and pneumonia deaths from the National Center for Health Statistics (NCHS. Age- and sex-specific death rates, and age-standardized death rates, were calculated. Using negative binomial Serfling-type methods, excess mortality was calculated separately by sex and age groups. RESULTS: In many age groups, observed pneumonia and influenza cause-specific mortality rates in October and November 2009 broke month-specific records since 1959 when the current series of detailed US mortality data began. Compared to the typical pattern of seasonal flu deaths, the 2009 pandemic age-specific mortality, as well as influenza-attributable (excess mortality, skewed much younger. We estimate 2,634 excess pneumonia and influenza deaths in 2009-10; the excess death rate in 2009 was 0.79 per 100,000. CONCLUSIONS: Pandemic influenza mortality skews younger than seasonal influenza. This can be explained by a protective effect due to antigenic cycling. When older cohorts have been previously exposed to a similar antigen, immune memory results in lower death rates at older ages. Age-targeted vaccination of younger people should be considered in future pandemics.

  17. Recurrent mass mortalities of the blueback herring, Alosa aestivalis, in the lower Connecticut River

    International Nuclear Information System (INIS)

    Moss, S.A.; Leggett, W.C.; Boyd, W.A.

    1976-01-01

    The authors studied 5 mass mortalities of blueback herring, Alosa aestivalis between 1965 and 1971. The reach of the Connecticut River in which the mortalities were observed includes the region thermally influenced by cooling water effluents from the Connecticut Yankee Atomic Power Plant. This warm water effluent has not been related to catastrophic blueback herring mortalities to the present time. The mortalities observed in 1965, 1966, and 1967 occurred before the plant became operational. The years of no abnormal mortalities, 1968, 1969, and 1970 coincided with periods of near-maximum generating output by this power plant. Only in June, 1971, did power plant operation coincide with a mass mortality of herring. Nevertheless, the occurrence of herring mortalities in four years out of seven observed suggests that further deterioration of water quality in the Connecticut River may threaten the continued spawning success of this fish. 9 references, 4 figures, 4 tables

  18. [Temporal and spatial change of climate resources and meteorological disasters under climate change during winter crop growing season in Guangdong Province, China.

    Science.gov (United States)

    Wang, Hua; Chen, Hui Hua; Tang, Li Sheng; Wang, Juan Huai; Tang, Hai Yan

    2018-01-01

    Trend analysis method was applied to analyze the general variation characteristics of the climate resources and meteorological disasters of growing season of the winter planting in Guangdong before (1961-1996) and after climate warming (1997-2015). Percentile method was employed to determine thresholds for extreme cold and drought in major planting regions, and the characteristics of extreme disasters since climate warming were analyzed. The results showed that, by comparing 1997-2015 with 1961-1996, the heat value in winter growing season increased significantly. The belt with a higher heat value, where the average temperature was ≥15 ℃ and accumulated temperature was ≥2200 ℃·d, covered the main winter production regions as Shaoguan, Zhanjiang, Maoming, Huizhou, Meizhou and Guangzhou. Meanwhile, the precipitation witnessed a slight increase. The regions with precipitations of 250-350 mm included Zhanjiang, Maoming, Huizhou, Guangzhou and Meizhou. Chilling injury in the winter planting season in the regions decreased, the belt with an accumulated chilling of climate resources and the occurrence law of meteorological disasters in growing season.

  19. Covariability of seasonal temperature and precipitation over the Iberian Peninsula in high-resolution regional climate simulations (1001-2099)

    Science.gov (United States)

    Fernández-Montes, S.; Gómez-Navarro, J. J.; Rodrigo, F. S.; García-Valero, J. A.; Montávez, J. P.

    2017-04-01

    Precipitation and surface temperature are interdependent variables, both as a response to atmospheric dynamics and due to intrinsic thermodynamic relationships and feedbacks between them. This study analyzes the covariability of seasonal temperature (T) and precipitation (P) across the Iberian Peninsula (IP) using regional climate paleosimulations for the period 1001-1990, driven by reconstructions of external forcings. Future climate (1990-2099) was simulated according to SRES scenarios A2 and B2. These simulations enable exploring, at high spatial resolution, robust and physically consistent relationships. In winter, positive P-T correlations dominate west-central IP (Pearson correlation coefficient ρ = + 0.43, for 1001-1990), due to prevalent cold-dry and warm-wet conditions, while this relationship weakens and become negative towards mountainous, northern and eastern regions. In autumn, negative correlations appear in similar regions as in winter, whereas for summer they extend also to the N/NW of the IP. In spring, the whole IP depicts significant negative correlations, strongest for eastern regions (ρ = - 0.51). This is due to prevalent frequency of warm-dry and cold-wet modes in these regions and seasons. At the temporal scale, regional correlation series between seasonal anomalies of temperature and precipitation (assessed in 31 years running windows in 1001-1990) show very large multidecadal variability. For winter and spring, periodicities of about 50-60 years arise. The frequency of warm-dry and cold-wet modes appears correlated with the North Atlantic Oscillation (NAO), explaining mainly co-variability changes in spring. For winter and some regions in autumn, maximum and minimum P-T correlations appear in periods with enhanced meridional or easterly circulation (low or high pressure anomalies in the Mediterranean and Europe). In spring and summer, the Atlantic Multidecadal Oscillation shows some fingerprint on the frequency of warm/cold modes. For

  20. Excess mortality in Italy: Should we care about low influenza vaccine uptake?

    Science.gov (United States)

    Fausto, Francia; Paolo, Pandolfi; Anna, Odone; Carlo, Signorelli

    2018-03-01

    The aims of this study were to explore 2015 mortality data further and to assess excess deaths' determinants. We analysed data from a large metropolitan area in the north of Italy, the city of Bologna. We took advantage of a comprehensive local-level database and merged three different data sources to analitically explore reported 2014-2015 excess mortality and its determinants. Effect estimates were derived from multivariable Poisson regression analysis, according to vaccination status and frailty index. We report 9.8% excess mortality in 2015 compared to 2014, with seasonal and age distribution patterns in line with national figures. All-cause mortality in the elderly population is 36% higher (risk ratio [RR]=1.36, 95% confidence interval [CI] 1.27-1.45) in subjects not vaccinated against seasonal flu compared to vaccinated subjects, with risk of death for influenza or pneumonia being 43% higher (RR=1.43, 95% CI 1.02-2.00) in unvaccinated subjects. Reported excess mortality's determinants in Italy should be further explored. Elderly subjects not vaccinated against the flu appear to have increased risk of all-cause and cause-specific mortality compared to vaccinated subjects after accounting for possible confounders. Our findings raise awareness of the need to promote immunisation against the flu among elder populations and offer insights to plan and implement effective public-health interventions.

  1. Spatiotemporal analysis for the effect of ambient particulate matter on cause-specific respiratory mortality in Beijing, China.

    Science.gov (United States)

    Wang, Xuying; Guo, Yuming; Li, Guoxing; Zhang, Yajuan; Westerdahl, Dane; Jin, Xiaobin; Pan, Xiaochuan; Chen, Liangfu

    2016-06-01

    This study explored the association between particulate matter with an aerodynamic diameter of less than 10 μm (PM10) and the cause-specific respiratory mortality. We used the ordinary kriging method to estimate the spatial characteristics of ambient PM10 at 1-km × 1-km resolution across Beijing during 2008-2009 and subsequently fit the exposure-response relationship between the estimated PM10 and the mortality due to total respiratory disease, chronic lower respiratory disease, chronic obstructive pulmonary disease (COPD), and pneumonia at the street or township area levels using the generalized additive mixed model (GAMM). We also examined the effects of age, gender, and season in the stratified analysis. The effects of ambient PM10 on the cause-specific respiratory mortality were the strongest at lag0-5 except for pneumonia, and an inter-quantile range increase in PM10 was associated with an 8.04 % (95 % CI 4.00, 12.63) increase in mortality for total respiratory disease, a 6.63 % (95 % CI 1.65, 11.86) increase for chronic lower respiratory disease, and a 5.68 % (95 % CI 0.54, 11.09) increase for COPD, respectively. Higher risks due to the PM10 exposure were observed for females and elderly individuals. Seasonal stratification analysis showed that the effects of PM10 on mortality due to pneumonia were stronger during spring and autumn. While for COPD, the effect of PM10 in winter was statistically significant (15.54 %, 95 % CI 5.64, 26.35) and the greatest among the seasons. The GAMM model evaluated stronger associations between concentration of PM10. There were significant associations between PM10 and mortality due to respiratory disease at the street or township area levels. The GAMM model using high-resolution PM10 could better capture the association between PM10 and respiratory mortality. Gender, age, and season also acted as effect modifiers for the relationship between PM10 and respiratory mortality.

  2. Seasonal abundance and molecular identification of West Nile virus ...

    African Journals Online (AJOL)

    Seasonal abundance and molecular identification of West Nile virus vectors, Culex pipens and Culex ... Background: West Nile virus (WNV) infection, is an arbovirus infection with high morbidity and mortality, the vector respon- sible for both human ... Major diseases transmitted are known as Arboviral dis- eases because ...

  3. The association between air pollution and mortality in Thailand.

    Science.gov (United States)

    Guo, Yuming; Li, Shanshan; Tawatsupa, Benjawan; Punnasiri, Kornwipa; Jaakkola, Jouni J K; Williams, Gail

    2014-07-01

    Bayesian statistical inference with a case-crossover design was used to examine the effects of air pollutants {Particulate matter pollutants had significant short-term impacts on non-accidental mortality. An increase of 10 μg/m(3) in PM10, 10 ppb in O₃, 1 ppb in SO₂ were associated with a 0.40% (95% posterior interval (PI): 0.22, 0.59%), 0.78% (95% PI: 0.20, 1.35%) and 0.34% (95% PI: 0.17, 0.50%) increase of non-accidental mortality, respectively. O₃ air pollution is significantly associated with cardiovascular mortality, while PM10 is significantly related to respiratory mortality. In general, the effects of all pollutants on all mortality types were higher in summer and winter than those in the rainy season. This study highlights the effects of exposure to air pollution on mortality risks in Thailand. Our findings support the Thailand government in aiming to reduce high levels of air pollution.

  4. Photographs and herbarium specimens as tools to document phenological changes in response to global warming.

    Science.gov (United States)

    Miller-Rushing, Abraham J; Primack, Richard B; Primack, Daniel; Mukunda, Sharda

    2006-11-01

    Global warming is affecting natural systems across the world. Of the biological responses to warming, changes in the timing of phenological events such as flowering are among the most sensitive. Despite the recognized importance of phenological changes, the limited number of long-term records of phenological events has restricted research on the topic in most areas of the world. In a previous study in Boston (American Journal of Botany 91: 1260-1264), we used herbarium specimens and one season of field observations to show that plants flowered earlier as the climate warmed over the past 100 yr. In our new study, we found that two extra years of data did not strengthen the explanatory power of the analysis. Analysis of herbarium specimens without any field data yielded results similar to analyses that included field observations. In addition, we found that photographs of cultivated and wild plants in Massachusetts, data similar to that contained in herbarium specimens, show changes in flowering times that closely match independent data on the same species in the same locations. Dated photographs of plants in flower represent a new resource to extend the range of species and localities addressed in global-warming research.

  5. Ocean Warming Slows Coral Growth in the Central Red Sea

    KAUST Repository

    Cantin, N. E.; Cohen, A. L.; Karnauskas, K. B.; Tarrant, A. M.; McCorkle, D. C.

    2010-01-01

    Sea surface temperature (SST) across much of the tropics has increased by 0.4° to 1°C since the mid-1970s. A parallel increase in the frequency and extent of coral bleaching and mortality has fueled concern that climate change poses a major threat to the survival of coral reef ecosystems worldwide. Here we show that steadily rising SSTs, not ocean acidification, are already driving dramatic changes in the growth of an important reef-building coral in the central Red Sea. Three-dimensional computed tomography analyses of the massive coral Diploastrea heliopora reveal that skeletal growth of apparently healthy colonies has declined by 30% since 1998. The same corals responded to a short-lived warm event in 1941/1942, but recovered within 3 years as the ocean cooled. Combining our data with climate model simulations by the Intergovernmental Panel on Climate Change, we predict that should the current warming trend continue, this coral could cease growing altogether by 2070.

  6. Ocean Warming Slows Coral Growth in the Central Red Sea

    KAUST Repository

    Cantin, N. E.

    2010-07-15

    Sea surface temperature (SST) across much of the tropics has increased by 0.4° to 1°C since the mid-1970s. A parallel increase in the frequency and extent of coral bleaching and mortality has fueled concern that climate change poses a major threat to the survival of coral reef ecosystems worldwide. Here we show that steadily rising SSTs, not ocean acidification, are already driving dramatic changes in the growth of an important reef-building coral in the central Red Sea. Three-dimensional computed tomography analyses of the massive coral Diploastrea heliopora reveal that skeletal growth of apparently healthy colonies has declined by 30% since 1998. The same corals responded to a short-lived warm event in 1941/1942, but recovered within 3 years as the ocean cooled. Combining our data with climate model simulations by the Intergovernmental Panel on Climate Change, we predict that should the current warming trend continue, this coral could cease growing altogether by 2070.

  7. Artificial asymmetric warming reduces nectar yield in a Tibetan alpine species of Asteraceae.

    Science.gov (United States)

    Mu, Junpeng; Peng, Youhong; Xi, Xinqiang; Wu, Xinwei; Li, Guoyong; Niklas, Karl J; Sun, Shucun

    2015-11-01

    Asymmetric warming is one of the distinguishing features of global climate change, in which winter and night-time temperatures are predicted to increase more than summer and diurnal temperatures. Winter warming weakens vernalization and hence decreases the potential to flower for some perennial herbs, and night warming can reduce carbohydrate concentrations in storage organs. This study therefore hypothesized that asymmetric warming should act to reduce flower number and nectar production per flower in a perennial herb, Saussurea nigrescens, a key nectar plant for pollinators in Tibetan alpine meadows. A long-term (6 years) warming experiment was conducted using open-top chambers placed in a natural meadow and manipulated to achieve asymmetric increases in temperature, as follows: a mean annual increase of 0·7 and 2·7 °C during the growing and non-growing seasons, respectively, combined with an increase of 1·6 and 2·8 °C in the daytime and night-time, respectively, from June to August. Measurements were taken of nectar volume and concentration (sucrose content), and also of leaf non-structural carbohydrate content and plant morphology. Six years of experimental warming resulted in reductions in nectar volume per floret (64·7 % of control), floret number per capitulum (8·7 %) and capitulum number per plant (32·5 %), whereas nectar concentration remained unchanged. Depletion of leaf non-structural carbohydrates was significantly higher in the warmed than in the ambient condition. Overall plant density was also reduced by warming, which, when combined with reductions in flower development and nectar volumes, led to a reduction of ∼90 % in nectar production per unit area. The negative effect of asymmetric warming on nectar yields in S. nigrescens may be explained by a concomitant depletion of leaf non-structural carbohydrates. The results thus highlight a novel aspect of how climate change might affect plant-pollinator interactions and plant

  8. Seasonality in the relationship between El Nino and Indian Ocean dipole

    Energy Technology Data Exchange (ETDEWEB)

    Roxy, Mathew [Centro-Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Indian Institute of Tropical Meteorology, Centre for Climate Change Research, Pune (India); Gualdi, Silvio; Navarra, Antonio [Centro-Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Lee Drbohlav, Hae-Kyung [University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States)

    2011-07-15

    The seasonal change in the relationship between El Nino and Indian Ocean dipole (IOD) is examined using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40), and the twentieth century simulations (20c3m) from the Geophysical Fluid Dynamics Laboratory Coupled Model, version 2.1. It is found that, both in ERA-40 and the model simulations, the correlation between El Nino (Nino3 index) and the eastern part of the IOD (90-110 E; 10 S-equator) is predominantly positive from January to June, and then changes to negative from July to December. Correlation maps of atmospheric and oceanic variables with respect to the Nino3 index are constructed for each season in order to examine the spatial structure of their seasonal response to El Nino. The occurrence of El Nino conditions during January to March induces low-level anti-cyclonic circulation anomalies over the southeastern Indian Ocean, which counteracts the climatological cyclonic circulation in that region. As a result, evaporation decreases and the southeastern Indian Ocean warms up as the El Nino proceeds, and weaken the development of a positive phase of an IOD. This warming of the southeastern Indian Ocean associated with the El Nino does not exist past June because the climatological winds there develop into the monsoon-type flow, enhancing the anomalous circulation over the region. Furthermore, the development of El Nino from July to September induces upwelling in the southeastern Indian Ocean, thereby contributing to further cooling of the region during the summer season. This results in the enhancement of a positive phase of an IOD. Once the climatological circulation shifts from the boreal summer to winter mode, the negative correlation between El Nino and SST of the southeastern Indian Ocean changes back to a positive one. (orig.)

  9. Magnitudes and timing of seasonal peak snowpack water equivalents in Arizona: A preliminary study of the possible effects of recent climatic change

    Science.gov (United States)

    Peter F. Ffolliott; Gerald J. Gottfried

    2010-01-01

    Field measurements and computer-based predictions suggest that the magnitudes of seasonal peak snowpack water equivalents are becoming less and the timing of these peaks is occurring earlier in the snowmelt-runoff season of the western United States. These changes in peak snowpack conditions have often been attributed to a warming of the regional climate. To determine...

  10. Failure of Aedes albopictus to overwinter following introduction and seasonal establishment at a tire recycling plant in the northeastern USA.

    Science.gov (United States)

    Andreadis, Theodore G

    2009-03-01

    In July 2006, an introduction of the Asian tiger mosquito, Aedes albopictus, was documented for the first time at a commercial tire recycling plant in northeastern Connecticut, USA. The introduction likely occurred via transport of infested tires originating from northern New Jersey or metropolitan New York City. Efforts were made to determine seasonal establishment and overwintering success by assessing adult biting and oviposition activity in the surrounding woodlands. The first adult female was collected in a CO2-baited Mosquito Magnet Liberty trap within the confines of the tire plant during the week of July 28. Additional females were collected intermittently thereafter through October 16. Host-seeking female Ae. albopictus attempting to alight on human subjects and larvae hatching from eggs collected in ovitraps placed in the woodlands surrounding the tire plant were detected weekly from August 21 through October 2, denoting seasonal establishment in the adjoining woodlands. However, no larvae of Ae. albopictus were recovered from eggs collected in ovitraps that were placed in the surrounding woodlands or in traps placed 1.0-1.6 km away, nor were any host-seeking females detected by human subjects the following season (July to October 2007), indicating that the species did not survive winter conditions to enable successful colonization. The failure of Ae. albopictus to overwinter and establish itself in the forested woodlands following several weeks of seasonal breeding and oviposition during the summer and early fall were most likely due to winter egg mortality, interspecific competition from Aedes triseriatus and Aedes japonicus, and/or other ecological barriers. Permanent establishment of Ae. albopictus in New England is unlikely despite the recurring importation of infested used tires into recycling facilities. However, continued monitoring of such facilities for potential reinvasion is warranted especially in urban/suburban environs where global warming

  11. Local warming: daily temperature change influences belief in global warming.

    Science.gov (United States)

    Li, Ye; Johnson, Eric J; Zaval, Lisa

    2011-04-01

    Although people are quite aware of global warming, their beliefs about it may be malleable; specifically, their beliefs may be constructed in response to questions about global warming. Beliefs may reflect irrelevant but salient information, such as the current day's temperature. This replacement of a more complex, less easily accessed judgment with a simple, more accessible one is known as attribute substitution. In three studies, we asked residents of the United States and Australia to report their opinions about global warming and whether the temperature on the day of the study was warmer or cooler than usual. Respondents who thought that day was warmer than usual believed more in and had greater concern about global warming than did respondents who thought that day was colder than usual. They also donated more money to a global-warming charity if they thought that day seemed warmer than usual. We used instrumental variable regression to rule out some alternative explanations.

  12. Arctic warming, moisture increase and circulation changes observed in the Ny-Ålesund homogenized radiosonde record

    Science.gov (United States)

    Maturilli, Marion; Kayser, Markus

    2017-10-01

    Radiosonde measurements obtained at the Arctic site Ny-Ålesund (78.9°N, 11.9°E), Svalbard, from 1993 to 2014 have been homogenized accounting for instrumentation discontinuities by correcting known errors in the manufacturer provided profiles. The resulting homogenized radiosonde record is provided as supplementary material at http://doi.pangaea.de/10.1594/PANGAEA.845373. From the homogenized data record, the first Ny-Ålesund upper-air climatology of wind, temperature and humidity is presented, forming the background for the analysis of changes during the 22-year period. Particularly during the winter season, a strong increase in atmospheric temperature and humidity is observed, with a significant warming of the free troposphere in January and February up to 3 K per decade. This winter warming is even more pronounced in the boundary layer below 1 km, presumably amplified by mesoscale processes including e.g. orographic effects or the boundary layer capping inversion. Though the largest contribution to the increasing atmospheric water vapour column in winter originates from the lowermost 2 km, no increase in the contribution by specific humidity inversions is detected. Instead, we find an increase in the humidity content of the large-scale background humidity profiles. At the same time, the tropospheric flow in winter is found to occur less frequent from northerly directions and to the same amount more frequent from the South. We conclude that changes in the atmospheric circulation lead to an enhanced advection of warm and moist air from lower latitudes to the Svalbard region in the winter season, causing the warming and moistening of the atmospheric column above Ny-Ålesund, and link the observations to changes in the Arctic Oscillation.

  13. Respiratory hospital admissions and weather changes: a retrospective study in Charlottesville, Virginia, USA

    Science.gov (United States)

    Davis, Robert E.; Enfield, Kyle B.

    2018-06-01

    In most midlatitude locations, human morbidity and mortality are highly seasonal, with winter peaks driven by respiratory disease and associated comorbidities. But the transition between high and low mortality/morbidity months varies spatially. We use a measure of the thermal biophysical strain imposed on the respiratory system—the Acclimatization Thermal Strain Index (ATSI)—to examine respiratory hospital admissions in Charlottesville, VA. Daily respiratory admissions to the University of Virginia over a 19-year period are compared to ATSI values derived from hourly surface weather data acquired from the Charlottesville airport. Negative ATSI values (associated with transitions from warm (and humid) to cold (and dry) conditions) are related to admission peaks at seasonal and weekly timescales, whereas positive ATSI values (cold to warm) exhibit weaker relationships. This research marks the first application of the ATSI to human morbidity, and results suggest that respiratory strain may account for how people who are acclimated to different climates respond to short-term weather changes.

  14. Respiratory hospital admissions and weather changes: a retrospective study in Charlottesville, Virginia, USA

    Science.gov (United States)

    Davis, Robert E.; Enfield, Kyle B.

    2018-02-01

    In most midlatitude locations, human morbidity and mortality are highly seasonal, with winter peaks driven by respiratory disease and associated comorbidities. But the transition between high and low mortality/morbidity months varies spatially. We use a measure of the thermal biophysical strain imposed on the respiratory system—the Acclimatization Thermal Strain Index (ATSI)—to examine respiratory hospital admissions in Charlottesville, VA. Daily respiratory admissions to the University of Virginia over a 19-year period are compared to ATSI values derived from hourly surface weather data acquired from the Charlottesville airport. Negative ATSI values (associated with transitions from warm (and humid) to cold (and dry) conditions) are related to admission peaks at seasonal and weekly timescales, whereas positive ATSI values (cold to warm) exhibit weaker relationships. This research marks the first application of the ATSI to human morbidity, and results suggest that respiratory strain may account for how people who are acclimated to different climates respond to short-term weather changes.

  15. Wind turbines in Switzerland - Bat mortality; Eoliennes en Suisse - Mortalite de chauves-souris

    Energy Technology Data Exchange (ETDEWEB)

    Leuzinger, Y.; Lugon, A.; Bontadina, F.

    2008-03-15

    There are growing concerns about possible negative impact of wind turbines on bats. In this study we evaluated the occurrence of bat mortality caused by wind turbines in Switzerland. From about 20 existing wind turbines in year 2007 we selected five medium to large sized turbines in two hilly regions of Switzerland. Between June and October we searched 10 times in regular intervals for carcasses on the ground (total 50 controls) in a circle of up to 40 m distance to the tower. We measured detectability and bait removal rates by experiments at every site (using 12 dummy bats and 10 dead mice per site, respectively). Two bat carcasses were found at two sites, one of the migrating species N. leisleri in August, another in September, belonging to the non-migrating species P. pipistrellus. The detectability was 74 {+-} 13% (mean {+-} standard deviation). The removal rate was 72 {+-} 25% in the first 2-3 days and an average of 91% in the control intervals of 15 days. Estimates of seasonal bat mortality, corrected for season, detectability and removal rate, revealed an average of 8.2 (range 4.9 - 11.4) dead bats per turbine and season. This study demonstrates the occurrence of bat mortality caused by wind turbines in Switzerland. However, the estimated mortality per season remains in international comparisons small to medium at the studied sites. The mortality of individuals of endangered and protected species is a serious issue, but most important, the long-term effect on populations is difficult to assess. In the case of the investigated wind turbines the negative impact on bats does not generally preclude the development of wind energy sites in Switzerland. We recommend avoiding sites in and near woodlands. The abundance of local and migratory bats at planned sites should be evaluated, obligatory in the case of larger wind parks and at exposed sites (ridge tops, mountain passes, river valleys), in order to consider adequately bat conservation. (author)

  16. Experimental warming differentially affects microbial structure and activity in two contrasted moisture sites in a Sphagnum-dominated peatland.

    Science.gov (United States)

    Delarue, Frédéric; Buttler, Alexandre; Bragazza, Luca; Grasset, Laurent; Jassey, Vincent E J; Gogo, Sébastien; Laggoun-Défarge, Fatima

    2015-04-01

    Several studies on the impact of climate warming have indicated that peat decomposition/mineralization will be enhanced. Most of these studies deal with the impact of experimental warming during summer when prevalent abiotic conditions are favorable to decomposition. Here, we investigated the effect of experimental air warming by open-top chambers (OTCs) on water-extractable organic matter (WEOM), microbial biomasses and enzymatic activities in two contrasted moisture sites named Bog and Fen sites, the latter considered as the wetter ones. While no or few changes in peat temperature and water content appeared under the overall effect of OTCs, we observed that air warming smoothed water content differences and led to a decrease in mean peat temperature at the warmed Bog sites. This thermal discrepancy between the two sites led to contrasting changes in microbial structure and activities: a rise in hydrolytic activity at the warmed Bog sites and a relative enhancement of bacterial biomass at the warmed Fen sites. These features were not associated with any change in WEOM properties namely carbon and sugar contents and aromaticity, suggesting that air warming did not trigger any shift in OM decomposition. Using various tools, we show that the use of single indicators of OM decomposition can lead to fallacious conclusions. Lastly, these patterns may change seasonally as a consequence of complex interactions between groundwater level and air warming, suggesting the need to improve our knowledge using a high time-resolution approach. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Association between daily mortality from respiratory and cardiovascular diseases and air pollution in Taiwan.

    Science.gov (United States)

    Liang, Wen-Miin; Wei, Hsing-Yu; Kuo, Hsien-Wen

    2009-01-01

    Many studies have investigated the effects of air pollutants on disease and mortality. However, the results remain inconsistent and inconclusive. We thought that the impact of different seasons or ages of people may explain these differences. Measurement of the five pollutants (particulate matter or =65 group). Data on daily mortality caused by respiratory disease, cardiovascular disease, and all other causes including the two aforementioned was collected by the Taiwan Department of Health (DOH). A time-series regression model was used to analyze the relative risk of respiratory and cardiovascular diseases due to air pollution in the summer and winter seasons. Risk of death from all causes and mortality from cardiovascular diseases during winter was significantly positively correlated with levels of SO(2), CO, and NO(2) for both groups of subjects and additionally with PM(10) for the elderly (> or =65 years old) group. There were significant positive correlations with respiratory diseases and levels of O(3) for both groups. However, the only significant positive correlation was with O(3) (RR=1.283) for the elderly group during summer. No other parameters showed significance for either group. Our findings contribute to the evidence of an association between SO(2), CO, NO(2), and PM(10) and mortality from respiratory and cardiovascular diseases, especially among elderly people during the winter season.

  18. Emissions of BVOC from lodgepole pine in response to mountain pine beetle attack in high and low mortality forest stands

    Directory of Open Access Journals (Sweden)

    T. R. Duhl

    2013-01-01

    Full Text Available In this screening study, biogenic volatile organic compound (BVOC emissions from intact branches of lodgepole pine (Pinus contorta trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB, with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site observed seasonal variability in emissions. A brief comparison is made of geological and climatic characteristics as well as prior disturbances (both natural and man-made at each site. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQTs compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly infested trees. SQT profiles differed between the two sites and, like monoterpene and oxygenated VOC profiles, varied through the season. For the low-mortality site in which repeated measurements were made over the course of the early summer–late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT, with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of 2-methyl-3-buten-2-ol (MBO had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late-season

  19. Climate warming: a loss of variation in populations can accompany reproductive shifts.

    Science.gov (United States)

    Massot, Manuel; Legendre, Stéphane; Fédérici, Pierre; Clobert, Jean

    2017-09-01

    The most documented response of organisms to climate warming is a change in the average timing of seasonal activities (phenology). Although we know that these average changes can differ among species and populations, we do not know whether climate warming impacts within-population variation in phenology. Using data from five study sites collected during a 13-year survey, we found that the increase in spring temperatures is associated with a reproductive advance of 10 days in natural populations of common lizards (Zootoca vivipara). Interestingly, we show a correlated loss of variation in reproductive dates within populations. As illustrated by a model, this shortening of the reproductive period can have significant negative effects on population dynamics. Consequently, we encourage tests in other species to assess the generality of decreased variation in phenological responses to climate change. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  20. Associations between air temperature and cardio-respiratory mortality in the urban area of Beijing, China: a time-series analysis.

    Science.gov (United States)

    Liu, Liqun; Breitner, Susanne; Pan, Xiaochuan; Franck, Ulrich; Leitte, Arne Marian; Wiedensohler, Alfred; von Klot, Stephanie; Wichmann, H-Erich; Peters, Annette; Schneider, Alexandra

    2011-05-25

    Associations between air temperature and mortality have been consistently observed in Europe and the United States; however, there is a lack of studies for Asian countries. Our study investigated the association between air temperature and cardio-respiratory mortality in the urban area of Beijing, China. Death counts for cardiovascular and respiratory diseases for adult residents (≥15 years), meteorological parameters and concentrations of particulate air pollution were obtained from January 2003 to August 2005. The effects of two-day and 15-day average temperatures were estimated by Poisson regression models, controlling for time trend, relative humidity and other confounders if necessary. Effects were explored for warm (April to September) and cold periods (October to March) separately. The lagged effects of daily temperature were investigated by polynomial distributed lag (PDL) models. We observed a J-shaped exposure-response function only for 15-day average temperature and respiratory mortality in the warm period, with 21.3°C as the threshold temperature. All other exposure-response functions could be considered as linear. In the warm period, a 5°C increase of two-day average temperature was associated with a RR of 1.098 (95% confidence interval (95%CI): 1.057-1.140) for cardiovascular and 1.134 (95%CI: 1.050-1.224) for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.040 (95%CI: 0.990-1.093) for cardiovascular mortality. In the cold period, a 5°C increase of two-day average temperature was associated with a RR of 1.149 (95%CI: 1.078-1.224) for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.057 (95%CI: 1.022-1.094) for cardiovascular mortality. The effects remained robust after considering particles as additional confounders. Both increases and decreases in air temperature are associated with an increased risk of cardiovascular mortality. The effects of

  1. Associations between air temperature and cardio-respiratory mortality in the urban area of Beijing, China: a time-series analysis

    Directory of Open Access Journals (Sweden)

    Wiedensohler Alfred

    2011-05-01

    Full Text Available Abstract Background Associations between air temperature and mortality have been consistently observed in Europe and the United States; however, there is a lack of studies for Asian countries. Our study investigated the association between air temperature and cardio-respiratory mortality in the urban area of Beijing, China. Methods Death counts for cardiovascular and respiratory diseases for adult residents (≥15 years, meteorological parameters and concentrations of particulate air pollution were obtained from January 2003 to August 2005. The effects of two-day and 15-day average temperatures were estimated by Poisson regression models, controlling for time trend, relative humidity and other confounders if necessary. Effects were explored for warm (April to September and cold periods (October to March separately. The lagged effects of daily temperature were investigated by polynomial distributed lag (PDL models. Results We observed a J-shaped exposure-response function only for 15-day average temperature and respiratory mortality in the warm period, with 21.3°C as the threshold temperature. All other exposure-response functions could be considered as linear. In the warm period, a 5°C increase of two-day average temperature was associated with a RR of 1.098 (95% confidence interval (95%CI: 1.057-1.140 for cardiovascular and 1.134 (95%CI: 1.050-1.224 for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.040 (95%CI: 0.990-1.093 for cardiovascular mortality. In the cold period, a 5°C increase of two-day average temperature was associated with a RR of 1.149 (95%CI: 1.078-1.224 for respiratory mortality; a 5°C decrease of 15-day average temperature was associated with a RR of 1.057 (95%CI: 1.022-1.094 for cardiovascular mortality. The effects remained robust after considering particles as additional confounders. Conclusions Both increases and decreases in air temperature are associated with an

  2. Associations between ozone, PM2.5, and four pollen types on emergency department pediatric asthma events during the warm season in New Jersey: a case-crossover study.

    Science.gov (United States)

    Gleason, Jessie A; Bielory, Leonard; Fagliano, Jerald A

    2014-07-01

    Asthma is one of the most common chronic diseases among school-aged children in the United States. Environmental respiratory irritants exacerbate asthma among children. Understanding the impact of a variety of known and biologically plausible environmental irritants and triggers among children in New Jersey - ozone, fine particulate matter (PM2.5), tree pollen, weed pollen, grass pollen and ragweed - would allow for informed public health interventions. Time-stratified case-crossover design was used to study the transient impact of ozone, PM2.5 and pollen on the acute onset of pediatric asthma. Daily emergency department visits were obtained for children aged 3-17 years with a primary diagnosis of asthma during the warm season (April through September), 2004-2007 (inclusive). Bi-directional control sampling was used to select two control periods for each case for a total of 65,562 inclusion days. Since the period of exposure prior to emergency department visit may be the most clinically relevant, lag exposures were investigated (same day (lag0), 1, 2, 3, 4, and 5 as well as 3-day and 5-day moving averages). Multivariable conditional logistic regression controlling for holiday, school-in-session indicator, and 3-day moving average for temperature and relative humidity was used to examine the associations. Odds ratios are based on interquartile range (IQR) increases or 10 unit increases when IQR ranges were narrow. Single-pollutant models as well as multipollutant models were examined. Stratification on gender, race, ethnicity and socioeconomic status was explored. The associations with ozone and PM2.5 were strongest on the same day (lag0) of the emergency department visit (RR IQR=1.05, 95% CI 1.04-1.06) and (RR IQR=1.03, 95% CI 1.02-1.04), respectively, with a decreasing lag effect. Tree and weed pollen were associated with pediatric ED visits; the largest magnitudes of association was with the 5-day average (RR IQR=1.23, 95% CI 1.21-1.25) and (RR 10=1.13, 95% CI 1

  3. The Arctic-Subarctic Sea Ice System is Entering a Seasonal Regime: Implications for Future Arctic Amplication

    Science.gov (United States)

    Haine, T. W. N.; Martin, T.

    2017-12-01

    The loss of Arctic sea ice is a conspicuous example of climate change. Climate models project ice-free conditions during summer this century under realistic emission scenarios, reflecting the increase in seasonality in ice cover. To quantify the increased seasonality in the Arctic-Subarctic sea ice system, we define a non-dimensional seasonality number for sea ice extent, area, and volume from satellite data and realistic coupled climate models. We show that the Arctic-Subarctic, i.e. the northern hemisphere, sea ice now exhibits similar levels of seasonality to the Antarctic, which is in a seasonal regime without significant change since satellite observations began in 1979. Realistic climate models suggest that this transition to the seasonal regime is being accompanied by a maximum in Arctic amplification, which is the faster warming of Arctic latitudes compared to the global mean, in the 2010s. The strong link points to a peak in sea-ice-related feedbacks that occurs long before the Arctic becomes ice-free in summer.

  4. Estimates of Avian Mortality Attributed to Vehicle Collisions in Canada

    Directory of Open Access Journals (Sweden)

    Christine A. Bishop

    2013-12-01

    Full Text Available Although mortality of birds from collisions with vehicles is estimated to be in the millions in the USA, Europe, and the UK, to date, no estimates exist for Canada. To address this, we calculated an estimate of annual avian mortality attributed to vehicular collisions during the breeding and fledging season, in Canadian ecozones, by applying North American literature values for avian mortality to Canadian road networks. Because owls are particularly susceptible to collisions with vehicles, we also estimated the number of roadkilled Barn owls (Tyto alba in its last remaining range within Canada. (This species is on the IUCN red list and is also listed federally as threatened; Committee on the Status of Endangered Wildlife in Canada 2010, International Union for the Conservation of Nature 2012. Through seven Canadian studies in existence, 80 species and 2,834 specimens have been found dead on roads representing species from 14 orders of birds. On Canadian 1 and 2-lane paved roads outside of major urban centers, the unadjusted number of bird mortalities/yr during an estimated 4-mo (122-d breeding and fledging season for most birds in Canada was 4,650,137 on roads traversing through deciduous, coniferous, cropland, wetlands and nonagricultural landscapes with less than 10% treed area. On average, this represents 1,167 birds killed/100 km in Canada. Adjusted for scavenging, this estimate was 13,810,906 (3,462 dead birds/100 km. For barn owls, the unadjusted number of birds killed annually on 4-lane roads during the breeding and fledging season, within the species geographic range in southern British Columbia, was estimated as 244 owls and, when adjusted for scavenging and observer bias (3.6 factor, the total was 851 owls.

  5. Projected Increase in Lightning Strikes in the United States Due to Global Warming

    Science.gov (United States)

    Romps, D. M.; Seeley, J.; Vollaro, D.; Molinari, J.

    2014-12-01

    Lightning plays an important role in atmospheric chemistry and in the initiation of wildfires, but the impact of global warming on lightning rates is poorly constrained. The lightning flash rate is proposed here to be proportional to the convective available potential energy (CAPE) times the precipitation rate. Using observations, the product of CAPE and precipitation is found to explain the majority of variance in the time series of total cloud-to-ground lightning flashes over the contiguous United States (CONUS) on timescales ranging from diurnal to seasonal. The observations reveal that storms convert the CAPE of water mass to discharged lightning energy with an efficiency of about 1%. This proxy can be applied to global climate models, which provide predictions for the increase in lightning due to global warming. Results from 11 GCMs will be shown.

  6. Effects of elevated CO[sub 2], nutrition and climate warming on bud phenology in Sitka spruce (Pecea sitchensis) and the impact on the risk of frost damage

    Energy Technology Data Exchange (ETDEWEB)

    Murray, M.B.; Smith, R.I.; Leith, I.D.; Fowler, D.; Friend, A.D. (Inst. of Terrestrial Ecology, Penicuik, Midlothian (United Kingdom)); Lee, H.S.J.; Jarvis, P.G. (Edinburgh Univ., Edinburgh, Midlothian (United Kingdom))

    Effects of elevated CO[sub 2], clone, and plant nutrition on bud dormancy of Sitka spruce were examined. Sitka spruce seedlings were fumigated with ambient or elevated concentrations of CO[sub 2] in open-top chambers for three growing seasons. In 1991 and 1992, elevated CO[sub 2] delayed bud burst in the spring and advanced bud set in the autumn. In a second study, four clones of Sitka spruce taken from two provenances, at 43 and 54[degree] N, were fumigated with ambient or elevated CO[sub 2]. Elevated CO[sub 2] had no effect on bud dormancy of the Skidegate a clone, but it reduced the growing season of the North Bend b clone by 20 d. In a third study, Sitka spruce seedlings growing in ambient or elevated CO[sub 2] were supplied with one of three nutrient regimes, low (0.1), medium (0.5) and high (2.0 times potential) using a method and solution based on the Ingestad technique. Elevated CO[sub 2] did not affect bud dormancy using the high nutrient treatment, but it reduced the growing season of plants in low nutrient treatment by 22 d. The effect of elevated CO[sub 2] plus a 0, 2 or 4[degree]C climatic warming on the timing of bud burst was assessed using a simulation model and meteorological data from three sites. The model predicted that: doubling the CO[sub 2] concentration in the absence of climatic warming will delay the onset of bud burst at all three sites; climatic warming in ambient CO[sub 2] will hasten bud burst; and climatic warming in elevated CO[sub 2] will hasten bud burst but to a lesser extent than warming alone. At all sites, elevated CO[sub 2] and climatic warming increased the mean daily temperature on the date of bud burst, reducing the risk of frost damage. 42 refs., 6 figs., 2 tabs.

  7. German central solar heating plants with seasonal heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, D.; Marx, R.; Nussbicker-Lux, J.; Ochs, F.; Heidemann, W. [Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Pfaffenwaldring 6, D-70550 Stuttgart (Germany); Mueller-Steinhagen, H. [Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Pfaffenwaldring 6, D-70550 Stuttgart (Germany); Institute of Technical Thermodynamics (ITT), German Aerospace Centre (DLR), Stuttgart (Germany)

    2010-04-15

    Central solar heating plants contribute to the reduction of CO{sub 2}-emissions and global warming. The combination of central solar heating plants with seasonal heat storage enables high solar fractions of 50% and more. Several pilot central solar heating plants with seasonal heat storage (CSHPSS) built in Germany since 1996 have proven the appropriate operation of these systems and confirmed the high solar fractions. Four different types of seasonal thermal energy stores have been developed, tested and monitored under realistic operation conditions: Hot-water thermal energy store (e.g. in Friedrichshafen), gravel-water thermal energy store (e.g. in Steinfurt-Borghorst), borehole thermal energy store (in Neckarsulm) and aquifer thermal energy store (in Rostock). In this paper, measured heat balances of several German CSHPSS are presented. The different types of thermal energy stores and the affiliated central solar heating plants and district heating systems are described. Their operational characteristics are compared using measured data gained from an extensive monitoring program. Thus long-term operational experiences such as the influence of net return temperatures are shown. (author)

  8. The use of climate information to estimate future mortality from high ambient temperature: A systematic literature review

    Science.gov (United States)

    Arbuthnott, Katherine; Kovats, Sari; Hajat, Shakoor; Falloon, Pete

    2017-01-01

    Background and objectives Heat related mortality is of great concern for public health, and estimates of future mortality under a warming climate are important for planning of resources and possible adaptation measures. Papers providing projections of future heat-related mortality were critically reviewed with a focus on the use of climate model data. Some best practice guidelines are proposed for future research. Methods The electronic databases Web of Science and PubMed/Medline were searched for papers containing a quantitative estimate of future heat-related mortality. The search was limited to papers published in English in peer-reviewed journals up to the end of March 2017. Reference lists of relevant papers and the citing literature were also examined. The wide range of locations studied and climate data used prevented a meta-analysis. Results A total of 608 articles were identified after removal of duplicate entries, of which 63 were found to contain a quantitative estimate of future mortality from hot days or heat waves. A wide range of mortality models and climate model data have been used to estimate future mortality. Temperatures in the climate simulations used in these studies were projected to increase. Consequently, all the papers indicated that mortality from high temperatures would increase under a warming climate. The spread in projections of future climate by models adds substantial uncertainty to estimates of future heat-related mortality. However, many studies either did not consider this source of uncertainty, or only used results from a small number of climate models. Other studies showed that uncertainty from changes in populations and demographics, and the methods for adaptation to warmer temperatures were at least as important as climate model uncertainty. Some inconsistencies in the use of climate data (for example, using global mean temperature changes instead of changes for specific locations) and interpretation of the effects on

  9. Vertical Wave Coupling associated with Stratospheric Sudden Warming Events analyzed in an Isentropic-Coordinate NWP Model.

    Science.gov (United States)

    Bleck, R.; Sun, S.; Benjamin, S.; Brown, J. M.

    2017-12-01

    Two- to four-week predictions of stratospheric sudden warming events during the winter seasons of 1999-2014, carried out with a high-resolution icosahedral NWP model using potential temperature as vertical coordinate, are inspected for commonalities in the evolution of both minor and major warmings. Emphasis is on the evolution of the potential vorticity field at different levels in the stratosphere, as well as on the sign and magnitude of the vertical component of the Eliassen-Palm flux vector suggestive of wave forcing in either direction. Material is presented shedding light on the skill of the model (FIM, developed at NOAA/ESRL) in predicting stratospheric warmings generally 2 weeks in advance. With an icosahedral grid ideally suited for studying polar processes, and a vertical coordinate faithfully reproducing details in the evolution of the potential vorticity and EP flux vector fields, FIM is found to be a good tool for investigating the SSW mechanism.

  10. The decline in winter excess mortality in The Netherlands

    NARCIS (Netherlands)

    Kunst, A. E.; Looman, C. W.; Mackenbach, J. P.

    1991-01-01

    In most countries, numbers of deaths rise considerably during the winter season. This winter excess in mortality has, however, been declining during recent decades. The causes of this decline are hardly known. This paper attempts to derive a number of hypotheses on the basis of a detailed

  11. Spatio-temporal variations of vegetation indicators in Eastern Siberia under global warming

    Science.gov (United States)

    Varlamova, Eugenia V.; Solovyev, Vladimir S.

    2017-11-01

    Study of spatio-temporal variations of NDVI (Normalized Difference Vegetation Index) and phenological parameters of Eastern Siberia vegetation cover under global warming was carried out on AVHRR/NOAA data (1982-2014). Trend maps of NDVI and annual variations of phenological parameters and NDVI are analyzed. A method based on stable transition of air temperature through +5°C was used to estimate the beginning, end and the length of the growing season. Correlation between NDVI and phenological parameters, surface air temperature and precipitation are discussed.

  12. Seasonal variation in thoracic vessel calcifications: Evidence from a chest computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Vehmas, Tapio; Leino-Arjas, Paeivi (Health and Work Ability, Finnish Inst. of Occupational Health, Helsinki (Finland)), e-mail: tapio.vehmas@ttl.fi; Hiltunen, Asta (Dept. of Radiology, Central Hospital of Laensi-Pohja, Kemi (Finland))

    2010-01-15

    Background: Cardiovascular disease incidence and mortality exhibit a winter peak and a summer trough, a fact that could have radiological manifestations. Purpose: To identify possible seasonal trends in the occurrence of thoracic vessel calcifications. Material and Methods: 505 male construction workers (aged 39-80 years) were each imaged once with chest spiral computed tomography (CT) during a 2-year period. Based on visual assessment of calcified plaques (0=no, 1=slight, 2=moderate, 3=extensive calcification), sum scores of atherosclerosis in coronary arteries, in the thoracic aorta, in the pre-cervical artery bases, and overall were constructed. The scores were regressed on the annual rank number of the CT day. Results: By using the cubic regression model, seasonal variation in calcified plaques in coronary arteries (P=0.003), in pre-cervical artery origins (P=0.015), and in the overall sum score (P=0.004) was observed. The peak occurred in January-February and the nadir in August. Depending on the model, about 2-3% of the variation in atherosclerotic calcifications could be explained by the season of imaging. Conclusion: The observed seasonal trend in calcifications parallels with mortality reports. Seasonal variations should be considered in atherosclerosis treatment studies. Confirmatory studies using modern imaging technology are needed in different countries and geographical locations, preferably with repeat imaging of the same individuals

  13. Calf management practices and associations with herd-level morbidity and mortality on beef cow-calf operations.

    Science.gov (United States)

    Murray, C F; Fick, L J; Pajor, E A; Barkema, H W; Jelinski, M D; Windeyer, M C

    2016-03-01

    The objective of this study was to investigate calf management practices on beef cow-calf operations and determine associations with herd-level morbidity and mortality of pre-weaned calves. A 40-question survey about management practices, morbidity and mortality was administered to cow-calf producers by distributing paper surveys and by circulating an online link through various media. A total of 267 producers completed the survey. Data were analyzed with descriptive statistics and multivariable linear regression models. Average herd-level treatment risk for pre-weaning calf diarrhea (PCD) and bovine respiratory disease (BRD) were 4.9% and 3.0%, respectively. Average herd-level mortality within the first 24 h of life (stillbirth), from 1 to 7 days and 7 days to weaning were 2.3%, 1.1%, and 1.4%, respectively. Operations that never intervened at parturition had 4.7% higher PCD than those that occasionally did. On operations using small elastrator bands for castration, PCD was 1.9% higher than those using other methods. For every increase of 100 cows in herd size, BRD decreased by 1.1%. The association between BRD and PCD varied by when calving season began. Operations that used off-farm, frozen colostrum had a 1.1% increase in stillbirths. Operations that verified a calf had suckled had 0.7% lower mortality from 1 to 7 days of age. Those that intervened when colostrum was abnormal or that used small elastrator bands for castration had 1.9% and 1.4% higher mortality during the 1st week of life, respectively, compared with other operations. Mortality from 7 days to weaning was lower by 0.7% when calving season started in April compared with January or February and was higher by 1.0% for each additional week of calving season. Operations that intervened with colostrum consumption for assisted calvings had lower mortality from 7 days to weaning by 0.8% compared with those that did not. For every 1.0% increase in BRD, mortality from 7 days to weaning increased by 1

  14. Evolution determines how global warming and pesticide exposure will shape predator-prey interactions with vector mosquitoes.

    Science.gov (United States)

    Tran, Tam T; Janssens, Lizanne; Dinh, Khuong V; Op de Beeck, Lin; Stoks, Robby

    2016-07-01

    How evolution may mitigate the effects of global warming and pesticide exposure on predator-prey interactions is directly relevant for vector control. Using a space-for-time substitution approach, we addressed how 4°C warming and exposure to the pesticide endosulfan shape the predation on Culex pipiens mosquitoes by damselfly predators from replicated low- and high-latitude populations. Although warming was only lethal for the mosquitoes, it reduced predation rates on these prey. Possibly, under warming escape speeds of the mosquitoes increased more than the attack efficiency of the predators. Endosulfan imposed mortality and induced behavioral changes (including increased filtering and thrashing and a positional shift away from the bottom) in mosquito larvae. Although the pesticide was only lethal for the mosquitoes, it reduced predation rates by the low-latitude predators. This can be explained by the combination of the evolution of a faster life history and associated higher vulnerabilities to the pesticide (in terms of growth rate and lowered foraging activity) in the low-latitude predators and pesticide-induced survival selection in the mosquitoes. Our results suggest that predation rates on mosquitoes at the high latitude will be reduced under warming unless predators evolve toward the current low-latitude phenotype or low-latitude predators move poleward.

  15. Precipitation thresholds and drought-induced tree die-off: insights from patterns of Pinus edulis mortality along an environmental stress gradient.

    Science.gov (United States)

    Clifford, Michael J; Royer, Patrick D; Cobb, Neil S; Breshears, David D; Ford, Paulette L

    2013-10-01

    Recent regional tree die-off events appear to have been triggered by a combination of drought and heat - referred to as 'global-change-type drought'. To complement experiments focused on resolving mechanisms of drought-induced tree mortality, an evaluation of how patterns of tree die-off relate to highly spatially variable precipitation is needed. Here, we explore precipitation relationships with a die-off event of pinyon pine (Pinus edulis Engelm.) in southwestern North America during the 2002-2003 global-change-type drought. Pinyon die-off and its relationship with precipitation was quantified spatially along a precipitation gradient in north-central New Mexico with standard field plot measurements of die-off combined with canopy cover derived from normalized burn ratio (NBR) from Landsat imagery. Pinyon die-off patterns revealed threshold responses to precipitation (cumulative 2002-2003) and vapor pressure deficit (VPD), with little to no mortality (< 10%) above 600 mm and below warm season VPD of c. 1.7 kPa. [Correction added after online publication 17 June 2013; in the preceding sentence, the word 'below' has been inserted.] Our results refine how precipitation patterns within a region influence pinyon die-off, revealing a precipitation and VPD threshold for tree mortality and its uncertainty band where other factors probably come into play - a response type that influences stand demography and landscape heterogeneity and is of general interest, yet has not been documented. © 2013 No claim to US Government works. New Phytologist © 2013 New Phytologist Trust.

  16. Ecophysiological responses of native and invasive grasses to simulated warming and drought

    Science.gov (United States)

    Ravi, S.; Law, D. J.; Wiede, A.; Barron-Gafford, G. A.; Breshears, D. D.; Dontsova, K.; Huxman, T. E.

    2011-12-01

    Climate models predict that many arid regions around the world - including the North American deserts - may become affected more frequently by recurrent droughts. At the same time, these regions are experiencing rapid vegetation transformations such as invasion by exotic grasses. Thus, understanding the ecophysiological processes accompanying exotic grass invasion in the context of rising temperatures and recurrent droughts is fundamental to global change research. Under ambient and warmer (+ 4° C) conditions inside the Biosphere 2 facility, we compared the ecophysiological responses (e.g. photosynthesis, stomatal conductance, pre-dawn leaf water potential, light & CO2 response functions, biomass) of a native grass - Heteropogan contortus (Tangle head) and an invasive grass - Pennisetum ciliare (Buffel grass) growing in single and mixed communities. Further, we monitored the physiological responses and mortality of these plant communities under moisture stress conditions, simulating a global change-type-drought. The results indicate that the predicted warming scenarios may enhance the invasibility of desert landscapes by exotic grasses. In this study, buffel grass assimilated more CO2 per unit leaf area and out-competed native grasses more efficiently in a warmer environment. However, scenarios involving a combination of drought and warming proved disastrous to both the native and invasive grasses, with drought-induced grass mortality occurring at much shorter time scales under warmer conditions.

  17. Global warming-setting the stages

    International Nuclear Information System (INIS)

    1994-01-01

    Most of us have heard or read about global warming. However, the messages we receive are often in conflict, raising more questions than answer. Is global warming a good or a bad thing? has it already started or is it part of our future? Are we, or are we not doing anything about it? Should we be concerned? This primer on Global Warming is designed to clear up some of this confusion by providing basic scientific information on global warming issue. It is clear that there is still much to learn about global warming. However, it is also clear that there is a lot that we already know - and that dose provide cause for concern. We must understand the global warming issue if we are to make wise decisions and take responsible actions in response to the challenges and opportunities posed by global warming. Chapter 1 of 'the primer on global Warming' set the stage with a brief overview of science of global warming within the context of climate change. In addition, it introduces the specific issues that surround the global warming problem. As far as the science of global warming is concerned the following questions are discussed. What is global climate? Is climate change natural? What causes climate to vary on a global scale? How does the composition of the atmosphere relate to climate change. but there are also certain issues discussed here which surround the global warming such as: If climate varies naturally, why is there a concern about 'global warming'? What are the potential consequences of 'global warning'. What human activities contribute to 'global warming'. (Author)

  18. Spatial variability and trends of seasonal snowmelt processes over Antarctic sea ice observed by satellite scatterometers

    Science.gov (United States)

    Arndt, S.; Haas, C.

    2017-12-01

    Snow is one of the key drivers determining the seasonal energy and mass budgets of sea ice in the Southern Ocean. Here, we analyze radar backscatter time series from the European Remote Sensing Satellites (ERS)-1 and-2 scatterometers, from the Quick Scatterometer (QSCAT), and from the Advanced Scatterometer (ASCAT) in order to observe the regional and inter-annual variability of Antarctic snowmelt processes from 1992 to 2014. On perennial ice, seasonal backscatter changes show two different snowmelt stages: A weak backscatter rise indicating the initial warming and metamorphosis of the snowpack (pre-melt), followed by a rapid rise indicating the onset of internal snowmelt and thaw-freeze cycles (snowmelt). In contrast, similar seasonal backscatter cycles are absent on seasonal ice, preventing the periodic retrieval of spring/summer transitions. This may be due to the dominance of ice bottom melt over snowmelt, leading to flooding and ice disintegration before strong snowmelt sets in. Resulting snowmelt onset dates on perennial sea ice show the expected latitudinal gradient from early melt onsets (mid-November) in the northern Weddell Sea towards late (end-December) or even absent snowmelt conditions further south. This result is likely related to seasonal variations in solar shortwave radiation (absorption). In addition, observations with different microwave frequencies allow to detect changing snow properties at different depths. We show that short wavelengths of passive microwave observations indicate earlier pre-melt and snowmelt onset dates than longer wavelength scatterometer observations, in response to earlier warming of upper snow layers compared to lower snow layers. Similarly, pre-melt and snowmelt onset dates retrieved from Ku-Band radars were earlier by an average of 11 and 23 days, respectively, than those retrieved from C-Band. This time difference was used to correct melt onset dates retrieved from Ku-Band to compile a consistent time series from

  19. Competition among warm season C4-cereals influence water use efficiency and competition ratios

    Directory of Open Access Journals (Sweden)

    Amanullah

    2015-12-01

    Full Text Available Water use efficiency (WUE and competition ratio (CR response of three warm season C4-cereals (grasses viz. corn (Zea mays L., cv. Hybrid-5393 VT3, grain sorghum (Sorghum bicolor L. Moench, cv. Hybrid-84G62 PAT, and foxtail millets (Setaria italic, cv. German Strain R in pure and mixed stands under low and high water levels was investigated. The experiment was conducted in pot experiment at Dryland Agriculture Institute, West Texas A&M University, Canyon, Texas, USA, during spring 2010. The objective of this study was to know whether the differences in the competitive ability of different crop species influence WUE or not? The planned mean comparison indicated that the corn WUE was 20, 11, and 6% higher in the mixed stand than in pure stand at 30, 60, and 90 days after emergence (DAE, respectively. The corn plants in pure stand had 91, 72, and 81% higher WUE than the average WUE of sorghum and millets in pure stand at 30, 60, and 90 DAE, respectively. Grain sorghum in pure stand had 70, 32, and 36% higher WUE than that of millets in pure stand at 30, 60, and 90 DAE, respectively. The WUE of three crops in mixed stand was 10 and 8% higher than the two crops mixed stand at the two early stages; but the WUE was 24% less in the three crops mixed stand than the two crops mixed stand at 90 DAE. Corn-mixed stand in two crops (average of corn + sorghum and corn + millets had 78, 74, and 74% higher WUE than the mixed stand of sorghum and millets at 30, 60, and 90 DAE, respectively. Corn and millets mixed stand had 14, 10, and 26% higher WUE than the corn and sorghum mixed stand at 30, 60, and 90 DAE, respectively. The increase in water level decreased WUE at the two late growth stages in all three crop plants. At the early growth stage (30 DAE, WUE increased in all crops at the higher water level. On the basis of CR, corn was found the best competitor, while millets was declared the least competitor in the mixed stands (corn

  20. Is microevolution the only emergency exit in a warming world? Temperature influences egg laying but not its underlying mechanisms in great tits

    NARCIS (Netherlands)

    Caro, S.P.; Schaper, S.V.; Dawson, A.; Sharp, P.; Gienapp, P.; Visser, M.E.

    2013-01-01

    Many bird species have advanced their seasonal timing in response to global warming, but we still know little about the causal effect of temperature. We carried out experiments in climate-controlled aviaries to investigate how temperature affects luteinizing hormone, prolactin, gonadal development,

  1. Effects of Forest Gaps on Litter Lignin and Cellulose Dynamics Vary Seasonally in an Alpine Forest

    Directory of Open Access Journals (Sweden)

    Han Li

    2016-01-01

    Full Text Available To understand how forest gaps and the associated canopy control litter lignin and cellulose dynamics by redistributing the winter snow coverage and hydrothermal conditions in the growing season, a field litterbag trial was conducted in the alpine Minjiang fir (Abies faxoniana Rehder and E.H. Wilson forest in a transitional area located in the upper reaches of the Yangtze River and the eastern Tibetan Plateau. Over the first year of litter decomposition, the litter exhibited absolute cellulose loss and absolute lignin accumulation except for the red birch litter. The changes in litter cellulose and lignin were significantly affected by the interactions among gap position, period and species. Litter cellulose exhibited a greater loss in the winter with the highest daily loss rate observed during the snow cover period. Both cellulose and lignin exhibited greater changes under the deep snow cover at the gap center in the winter, but the opposite pattern occurred under the closed canopy in the growing season. The results suggest that decreased snowpack seasonality due to winter warming may limit litter cellulose and lignin degradation in alpine forest ecosystems, which could further inhibit litter decomposition. As a result, the ongoing winter warming and gap vanishing would slow soil carbon sequestration from foliar litter in cold biomes.

  2. TNFα and IL-6 Responses to Particulate Matter in Vitro: Variation According to PM Size, Season, and Polycyclic Aromatic Hydrocarbon and Soil Content

    Science.gov (United States)

    Manzano-León, Natalia; Serrano-Lomelin, Jesús; Sánchez, Brisa N.; Quintana-Belmares, Raúl; Vega, Elizabeth; Vázquez-López, Inés; Rojas-Bracho, Leonora; López-Villegas, Maria Tania; Vadillo-Ortega, Felipe; De Vizcaya-Ruiz, Andrea; Perez, Irma Rosas; O’Neill, Marie S.; Osornio-Vargas, Alvaro R.

    2015-01-01

    Background: Observed seasonal differences in particulate matter (PM) associations with human health may be due to their composition and to toxicity-related seasonal interactions. Objectives: We assessed seasonality in PM composition and in vitro PM pro-inflammatory potential using multiple PM samples. Methods: We collected 90 weekly PM10 and PM2.5 samples during the rainy-warm and dry-cold seasons in five urban areas with different pollution sources. The elements, polycyclic aromatic hydrocarbons (PAHs), and endotoxins identified in the samples were subjected to principal component analysis (PCA). We tested the potential of the PM to induce tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6) secretion in cultured human monocytes (THP-1), and we modeled pro-inflammatory responses using the component scores. Results: PM composition varied by size and by season. PCA identified two main components that varied by season. Combustion-related constituents (e.g., vanadium, benzo[a]pyrene, benzo[a]anthracene) mainly comprised component 1 (C1). Soil-related constituents (e.g., endotoxins, silicon, aluminum) mainly comprised component 2 (C2). PM from the rainy-warm season was high in C2. PM (particularly PM2.5) from the dry-cold season was rich in C1. Elevated levels of cytokine production were associated with PM10 and C2 (rainy-warm season), whereas reduced levels of cytokine production were associated with PM2.5 and C1 (dry-cold season). TNFα secretion was increased following exposure to PM with high (vs. low) C2 content, but TNFα secretion in response to PM was decreased following exposure to samples containing ≥ 0.1% of C1-related PAHs, regardless of C2 content. The results of the IL-6 assays suggested more complex interactions between PM components and particle size. Conclusions: Variations in PM soil and PAH content underlie seasonal and PM size–related patterns in TNFα secretion. These results suggest that the mixture of components in PM explains some

  3. WARM BREEZE FROM THE STARBOARD BOW: A NEW POPULATION OF NEUTRAL HELIUM IN THE HELIOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Kubiak, M. A.; Bzowski, M.; Sokół, J. M.; Swaczyna, P.; Grzedzielski, S. [Space Research Centre of the Polish Academy of Sciences, Warsaw (Poland); Alexashov, D. B.; Izmodenov, V. V. [Space Research Institute (IKI) of the Russian Academy of Sciences, Moscow (Russian Federation); Möbius, E.; Leonard, T. [Space Research Center and Department of Physics, University of New Hampshire, Durham, NH (United States); Fuselier, S. A.; McComas, D. J. [Southwest Research Institute, San Antonio, TX (United States); Wurz, P. [Physics Institute, University of Bern, Bern (Switzerland)

    2014-08-01

    We investigate the signals from neutral helium atoms observed in situ from Earth orbit in 2010 by the Interstellar Boundary Explorer (IBEX). The full helium signal observed during the 2010 observation season can be explained as a superposition of pristine neutral interstellar He gas and an additional population of neutral helium that we call the Warm Breeze. The Warm Breeze is approximately 2 times slower and 2.5 times warmer than the primary interstellar He population, and its density in front of the heliosphere is ∼7% that of the neutral interstellar helium. The inflow direction of the Warm Breeze differs by ∼19° from the inflow direction of interstellar gas. The Warm Breeze seems to be a long-term, perhaps permanent feature of the heliospheric environment. It has not been detected earlier because it is strongly ionized inside the heliosphere. This effect brings it below the threshold of detection via pickup ion and heliospheric backscatter glow observations, as well as by the direct sampling of GAS/Ulysses. We discuss possible sources for the Warm Breeze, including (1) the secondary population of interstellar helium, created via charge exchange and perhaps elastic scattering of neutral interstellar He atoms on interstellar He{sup +} ions in the outer heliosheath, or (2) a gust of interstellar He originating from a hypothetic wave train in the Local Interstellar Cloud. A secondary population is expected from models, but the characteristics of the Warm Breeze do not fully conform to modeling results. If, nevertheless, this is the explanation, IBEX-Lo observations of the Warm Breeze provide key insights into the physical state of plasma in the outer heliosheath. If the second hypothesis is true, the source is likely to be located within a few thousand AU from the Sun, which is the propagation range of possible gusts of interstellar neutral helium with the Warm Breeze characteristics against dissipation via elastic scattering in the Local Cloud. Whatever the

  4. Soil Moisture and Sea Surface Temperatures equally important for Land Climate in the Warm Season

    Science.gov (United States)

    Orth, R.; Seneviratne, S. I.

    2015-12-01

    Both sea surface temperatures (SSTs) and soil moisture (SM) are important drivers of climate variability over land. In this study we present a comprehensive comparison of SM versus SST impacts on land climate in the warm season. We perform ensemble experiments with the Community Earth System Model (CESM) where we set SM or SSTs to median conditions, respectively, to remove their inter-annual variability, whereby the other component - SST or SM - is still interactively computed. In contrast to earlier experiments performed with prescribed SSTs, our experiments suggest that SM is overall as important as SSTs for land climate, not only in the midlatitudes but also in the tropics and subtropics. Mean temperature and precipitation are reduced by 0.1-0.5 K and 0-0.2 mm, respectively, whereas their variability at different time scales decreases by 10-40% (temperature) and 0-10% (precipitation) when either SM or SSTs are prescribed. Also drought occurrence is affected, with mean changes in the maximum number of cumulative dry days of 0-0.75 days. Both SM and SST-induced changes are strongest for hot temperatures (up to 0.7 K, and 50%), extreme precipitation (up to 0.4 mm, and 20%), and strong droughts (up to 2 days). Local climate changes in response to removed SM variability are controlled - to first order - by the land-atmosphere coupling and the natural SM variability. SST-related changes are partly controlled by the relation of local temperature or precipitation with the El Niño-Southern Oscillation. Moreover removed SM or SST variabilities both induce remote effects by impacting the atmospheric circulation. Our results are similar for the present day and the end of the century. We investigate the inter-dependency between SM and SST and find a sufficient degree of independence for the purpose of this study. The robustness of our findings is shown by comparing the response of CESM to removed SM variability with four other global climate models. In summary, SM and SSTs

  5. The cost of feeding bred dairy heifers on native warm-season grasses and harvested feedstuffs.

    Science.gov (United States)

    Lowe, J K; Boyer, C N; Griffith, A P; Waller, J C; Bates, G E; Keyser, P D; Larson, J A; Holcomb, E

    2016-01-01

    Heifer rearing is one of the largest production expenses for dairy cattle operations, which is one reason milking operations outsource heifer rearing to custom developers. The cost of harvested feedstuffs is a major expense in heifer rearing. A possible way to lower feed costs is to graze dairy heifers, but little research exists on this topic in the mid-south United States. The objectives of this research were to determine the cost of feeding bred dairy heifers grazing native warm-season grasses (NWSG), with and without legumes, and compare the cost of grazing with the cost of rearing heifers using 3 traditional rations. The 3 rations were corn silage with soybean meal, corn silage with dry distillers grain, and a wet distillers grain-based ration. Bred Holstein heifers between 15- and 20-mo-old continuously grazed switchgrass (SG), SG with red clover (SG+RC), a big bluestem and Indiangrass mixture (BBIG), and BBIG with red clover (BBIG+RC) in Tennessee during the summer months. Total grazing days were calculated for each NWSG to determine the average cost/animal per grazing day. The average daily gain (ADG) was calculated for each NWSG to develop 3 harvested feed rations that would result in the same ADG over the same number of grazing day as each NWSG treatment. The average cost/animal per grazing day was lowest for SG ($0.48/animal/grazing d) and highest for BBIG+RC ($1.10/animal/grazing d). For both BBIG and SG, legumes increased the average cost/animal per grazing day because grazing days did not increase enough to account for the additional cost of the legumes. No difference was observed in ADG for heifers grazing BBIG (0.85 kg/d) and BBIG+RC (0.94 kg/d), and no difference was observed in ADG for heifers grazing SG (0.71 kg/d) and SG+RC (0.70 kg/d). However, the ADG for heifers grazing SG and SG+RC was lower than the ADG for heifers grazing either BBIG or BBIG+RC. The average cost/animal per grazing day was lower for all NWSG treatments than the average cost

  6. Controls on the meridional extent of tropical precipitation and its contraction under global warming

    Science.gov (United States)

    Donohoe, A.

    2017-12-01

    A method for decomposing changes and variability in the spatial structure of tropical precipitation into shifting (meridional translation), contracting, and intensifying modes of variability is introduced. We demonstrate that the shifting mode of tropical precipitation explains very little (20%) more of the tropical precipitation changes and variability. Furthermore, the contraction of tropical precipitation is highly correlated (R2 > 0.95) with an intensification of the precipitation in both the observations and forced modeled simulations. These results suggest that the simultaneous contraction and intensification of tropical precipitation is the dominant mode of variability and changes under external forcing. We speculate that tropical surface temperature controls this concurrent variability. Indeed, models robustly predict that tropical precipitation increases and meridionally contracts in response to increased CO2 and is reduced and meridionally expanded under glacial forcing and boundary conditions. In contrast, the directionality of the tropical precipitation shift is both ambiguous and small in magnitude in response to increased CO2. Furthermore, the ratio of the contraction/expansion to intensification/reduction is consistent in the continuum of climate states from the glacial climate to a modern climate to a 4XCO2 climate suggesting that the intensification and contraction are linked together via a single mechanism. We examine two mechanisms responsible for the contraction of the precipitation under global warming : i. the reduction of the seasonal cycle of energy input to the atmosphere due to sea ice retreat that results in the tropical precipitation remaining closer to the equator during the solsticial seasons and; ii. the increased gross moist stability of the tropical atmosphere as the surface warms resulting in a weaker cross-equatorial Hadley circulation during the solsticial seasons.

  7. Extended probit mortality model for zooplankton against transient change of PCO(2).

    Science.gov (United States)

    Sato, Toru; Watanabe, Yuji; Toyota, Koji; Ishizaka, Joji

    2005-09-01

    The direct injection of CO(2) in the deep ocean is a promising way to mitigate global warming. One of the uncertainties in this method, however, is its impact on marine organisms in the near field. Since the concentration of CO(2), which organisms experience in the ocean, changes with time, it is required to develop a biological impact model for the organisms against the unsteady change of CO(2) concentration. In general, the LC(50) concept is widely applied for testing a toxic agent for the acute mortality. Here, we regard the probit-transformed mortality as a linear function not only of the concentration of CO(2) but also of exposure time. A simple mathematical transform of the function gives a damage-accumulation mortality model for zooplankton. In this article, this model was validated by the mortality test of Metamphiascopsis hirsutus against the transient change of CO(2) concentration.

  8. Global warming and South Indian monsoon rainfall-lessons from the Mid-Miocene.

    Science.gov (United States)

    Reuter, Markus; Kern, Andrea K; Harzhauser, Mathias; Kroh, Andreas; Piller, Werner E

    2013-04-01

    Precipitation over India is driven by the Indian monsoon. Although changes in this atmospheric circulation are caused by the differential seasonal diabatic heating of Asia and the Indo-Pacific Ocean, it is so far unknown how global warming influences the monsoon rainfalls regionally. Herein, we present a Miocene pollen flora as the first direct proxy for monsoon over southern India during the Middle Miocene Climate Optimum. To identify climatic key parameters, such as mean annual temperature, warmest month temperature, coldest month temperature, mean annual precipitation, mean precipitation during the driest month, mean precipitation during the wettest month and mean precipitation during the warmest month the Coexistence Approach is applied. Irrespective of a ~ 3-4 °C higher global temperature during the Middle Miocene Climate Optimum, the results indicate a modern-like monsoonal precipitation pattern contrasting marine proxies which point to a strong decline of Indian monsoon in the Himalaya at this time. Therefore, the strength of monsoon rainfall in tropical India appears neither to be related to global warming nor to be linked with the atmospheric conditions over the Tibetan Plateau. For the future it implies that increased global warming does not necessarily entail changes in the South Indian monsoon rainfall.

  9. Long-term exposure to ambient ozone and mortality: a quantitative systematic review and meta-analysis of evidence from cohort studies.

    Science.gov (United States)

    Atkinson, R W; Butland, B K; Dimitroulopoulou, C; Heal, M R; Stedman, J R; Carslaw, N; Jarvis, D; Heaviside, C; Vardoulakis, S; Walton, H; Anderson, H R

    2016-02-23

    While there is good evidence for associations between short-term exposure to ozone and a range of adverse health outcomes, the evidence from narrative reviews for long-term exposure is suggestive of associations with respiratory mortality only. We conducted a systematic, quantitative evaluation of the evidence from cohort studies, reporting associations between long-term exposure to ozone and mortality. Cohort studies published in peer-reviewed journals indexed in EMBASE and MEDLINE to September 2015 and PubMed to October 2015 and cited in reviews/key publications were identified via search strings using terms relating to study design, pollutant and health outcome. Study details and estimate information were extracted and used to calculate standardised effect estimates expressed as HRs per 10 ppb increment in long-term ozone concentrations. 14 publications from 8 cohorts presented results for ozone and all-cause and cause-specific mortality. We found no evidence of associations between long-term annual O3 concentrations and the risk of death from all causes, cardiovascular or respiratory diseases, or lung cancer. 4 cohorts assessed ozone concentrations measured during the warm season. Summary HRs for cardiovascular and respiratory causes of death derived from 3 cohorts were 1.01 (95% CI 1.00 to 1.02) and 1.03 (95% CI 1.01 to 1.05) per 10 ppb, respectively. Our quantitative review revealed a paucity of independent studies regarding the associations between long-term exposure to ozone and mortality. The potential impact of climate change and increasing anthropogenic emissions of ozone precursors on ozone levels worldwide suggests further studies of the long-term effects of exposure to high ozone levels are warranted. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  10. Vertical Distribution of Temperature in Transitional Season II and West Monsoon in Western Pacific

    Science.gov (United States)

    Pranoto, Hikari A. H.; Kunarso; Soeyanto, Endro

    2018-02-01

    Western Pacific is the water mass intersection from both the Northern Pacific and Southern Pacific ocean. The Western Pacific ocean is warm pool area which formed by several warm surface currents. As a warm pool area and also the water mass intersection, western Pacific ocean becomes an interesting study area. The object of this study is to describe the temperature vertical distribution by mooring buoy and temporally in transitional season II (September - November 2014) and west monsoon (December 2014 - February 2015) in Western Pacific. Vertical temperature and wind speed data that was used in this study was recorded by INA-TRITON mooring instrument and obtained from Laboratory of Marine Survey, BPPT. Supporting data of this study was wind vector data from ECMWF to observe the relation between temperature distribution and monsoon. The quantitative approach was used in this study by processing temperature and wind data from INA-TRITON and interpreted graphically. In the area of study, it was found that in transitional season II the range of sea surface temperature to 500-meter depth was about 8.29 - 29.90 °C while in west monsoon was 8.12 - 29.45 °C. According to the research result, the sea SST of western Pacific ocean was related to monsoonal change with SST and wind speed correlation coefficient was 0.78. While the deep layer temperature was affected by water mass flow which passes through the western Pacific Ocean.

  11. Global Warming: A Reduced Threat?.

    Science.gov (United States)

    Michaels, Patrick J.; Stooksbury, David E.

    1992-10-01

    One popular and apocalyptic vision of the world influenced by increasing concentrations of infrared-absorbing trace gases is that of ecological disaster brought about by rapidly rising temperatures, sea level, and evaporation rates. This vision developed from a suite of climate models that have since considerably changed in both their dynamics and their estimates of prospective warming. Observed temperatures indicate that much more warming should already have taken place than predicted by earlier models in the Northern Hemisphere, and that night, rather than day, readings in that hemisphere show a relative warming. A high-latitude polar-night warming or a general night warming could be either benign or beneficial. A large number of plant species show both increased growth and greater water-use efficiency under enhanced carbon dioxide.An extensive body of evidence now indicates that anthropo-generated sulfate emissions are mitigating some of the warming, and that increased cloudiness as a result of these emissions will further enhance night, rather than day, warming. The sulfate emissions, though, are not sufficient to explain all of the night warming. However, the sensitivity of climate to anthropogenerated aerosols, and the general lack of previously predicted warming, could drastically alter the debate on global warming in favor of less expensive policies.

  12. Phytoplankton Community Structure in 2011-2013 Compared to the Extratropical Warming Event of 2014-2015

    Science.gov (United States)

    Du, X.; Peterson, W. T.

    2018-02-01

    Coastal waters of the Northern California Current experienced "normal" ocean conditions in 2011-2012, weak upwelling in 2013-2014, then suddenly warmed in September 2014. The response of phytoplankton community structure to contrasting ocean conditions was determined from samples collected off Newport, Oregon. Cluster analysis identified three prominent phytoplankton community types: one that occurred during the upwelling season characterized by the highest abundance and diversity of diatoms, a preupwelling/relaxation community characterized by lower abundance, lowest diversity of diatoms and dinoflagellates, and another one associated with the warm anomalies from September 2014 through 2015 with reduced diatom abundance and diversity but the highest dinoflagellate diversity. The changes of diatom and dinoflagellate community were correlated with local factors (silicate, silicate: nitrate ratios, temperature, and salinity), and with the Pacific Decadal Oscillation.

  13. Differential responses of invasive and native plants to warming with simulated changes in diurnal temperature ranges.

    Science.gov (United States)

    Chen, Bao-Ming; Gao, Yang; Liao, Hui-Xuan; Peng, Shao-Lin

    2017-07-01

    both the invasive and native plants, while the asymmetric summer warming treatments (DTR inc and DTR dec ) decreased the biomass of the invasive but not the native plants. In addition, wintertime DTR inc did not enhance the biomass of all the plants relative to DTR sym . Our results were obtained in an unrealistic setting; the growth conditions in chambers (e.g. low light, low herbivory, no competition) are quite different from natural conditions (high light, normal herbivory and competition), which may influence the effects of warming on the seedling establishment and growth of both invasive and native plants. Nonetheless, our work highlights the importance of asymmetric warming, particularly in regards to the comparison with the effects of symmetric warming on both invasive and native plants. Conclusions regarding the effects of future warming should be made cautiously because warming with different DTRs may suggest different implications for invasion, and effects of warming may be different in different seasons.

  14. Asymmetric responses to simulated global warming by populations of Colobanthus quitensis along a latitudinal gradient

    Directory of Open Access Journals (Sweden)

    Ian S. Acuña-Rodríguez

    2017-09-01

    Full Text Available The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, facilitating the colonization and spread of plant populations. Consequently, Antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities become progressively more departed from the species’ physiological optimum, the ecophysiological responses and survival to the expected global warming could be reduced. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (three years under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along the latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in these cold environments increases the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures respective to each site of origin after three growing seasons. Overall, was found a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations. Our results suggest that under a global warming scenario, plant populations that inhabiting cold zones at

  15. Asymmetric responses to simulated global warming by populations of Colobanthus quitensis along a latitudinal gradient.

    Science.gov (United States)

    Acuña-Rodríguez, Ian S; Torres-Díaz, Cristian; Hereme, Rasme; Molina-Montenegro, Marco A

    2017-01-01

    The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, facilitating the colonization and spread of plant populations. Consequently, Antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities become progressively more departed from the species' physiological optimum, the ecophysiological responses and survival to the expected global warming could be reduced. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (three years) under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along the latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in these cold environments increases the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures respective to each site of origin after three growing seasons. Overall, was found a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations. Our results suggest that under a global warming scenario, plant populations that inhabiting cold zones at high latitudes could

  16. Global Mortality Estimates for the 2009 Influenza Pandemic from the GLaMOR Project: A Modeling Study

    Science.gov (United States)

    Simonsen, Lone; Spreeuwenberg, Peter; Lustig, Roger; Taylor, Robert J.; Fleming, Douglas M.; Kroneman, Madelon; Van Kerkhove, Maria D.; Mounts, Anthony W.; Paget, W. John

    2013-01-01

    Background Assessing the mortality impact of the 2009 influenza A H1N1 virus (H1N1pdm09) is essential for optimizing public health responses to future pandemics. The World Health Organization reported 18,631 laboratory-confirmed pandemic deaths, but the total pandemic mortality burden was substantially higher. We estimated the 2009 pandemic mortality burden through statistical modeling of mortality data from multiple countries. Methods and Findings We obtained weekly virology and underlying cause-of-death mortality time series for 2005–2009 for 20 countries covering ∼35% of the world population. We applied a multivariate linear regression model to estimate pandemic respiratory mortality in each collaborating country. We then used these results plus ten country indicators in a multiple imputation model to project the mortality burden in all world countries. Between 123,000 and 203,000 pandemic respiratory deaths were estimated globally for the last 9 mo of 2009. The majority (62%–85%) were attributed to persons under 65 y of age. We observed a striking regional heterogeneity, with almost 20-fold higher mortality in some countries in the Americas than in Europe. The model attributed 148,000–249,000 respiratory deaths to influenza in an average pre-pandemic season, with only 19% in persons mortality was ∼10-fold higher than the World Health Organization's laboratory-confirmed mortality count. Although the pandemic mortality estimate was similar in magnitude to that of seasonal influenza, a marked shift toward mortality among persons mortality and hospitalization surveillance data is needed to rapidly establish the severity of future pandemics. Please see later in the article for the Editors' Summary PMID:24302890

  17. Significance of cold-season respiration and photosynthesis in a subarctic heath ecosystem in Northern Sweden

    DEFF Research Database (Denmark)

    Larsen, Klaus Steenberg; Ibrom, Andreas; Jonasson, S.

    2007-01-01

    While substantial cold-season respiration has been documented in most arctic and alpine ecosystems in recent years, the significance of cold-season photosynthesis in these biomes is still believed to be small. In a mesic, subartic heath during both the cold and warm season, we measured in situ...... ecosystem respiration and photosynthesis with a chamber technique at ambient conditions and at artificially, increased frequency of freeze-thaw (FT) cycles during fall and spring. We fitted the measured ecosystem exchange rates to respiration and photosynthesis models with R-2-values ranging from 0.81 to 0.......85. As expected, estimated cold-season (October, November, April and May) respiration was significant and accounted for at least 22% of the annual respiratory CO2 flux. More surprisingly, estimated photosynthesis during this period accounted for up to 19% of the annual gross CO2 uptake, suggesting that cold...

  18. Snowmelt response to simulated warming across a large elevation gradient, southern Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    K. N. Musselman

    2017-12-01

    Full Text Available In a warmer climate, the fraction of annual meltwater produced at high melt rates in mountainous areas is projected to decline due to a contraction of the snow-cover season, causing melt to occur earlier and under lower energy conditions. How snowmelt rates, including extreme events relevant to flood risk, may respond to a range of warming over a mountain front is poorly known. We present a model sensitivity study of snowmelt response to warming across a 3600 m elevation gradient in the southern Sierra Nevada, USA. A snow model was run for three distinct years and verified against extensive ground observations. To simulate the impact of climate warming on meltwater production, measured meteorological conditions were modified by +1 to +6 °C. The total annual snow water volume exhibited linear reductions (−10 % °C−1 consistent with previous studies. However, the sensitivity of snowmelt rates to successive degrees of warming varied nonlinearly with elevation. Middle elevations and years with more snowfall were prone to the largest reductions in snowmelt rates, with lesser changes simulated at higher elevations. Importantly, simulated warming causes extreme daily snowmelt (99th percentiles to increase in spatial extent and intensity, and shift from spring to winter. The results offer insight into the sensitivity of mountain snow water resources and how the rate and timing of water availability may change in a warmer climate. The identification of future climate conditions that may increase extreme melt events is needed to address the climate resilience of regional flood control systems.

  19. Soil Respiration Declines Following Beetle - Induced Forest Mortality in a Lodgepole Pine Forest

    Science.gov (United States)

    Borkhuu, B.; Peckham, S. D.; Norton, U.; Ewers, B. E.; Pendall, E.

    2014-12-01

    Lodgepole pine (Pinus contorta var. latifolia) forests in northern Colorado and southeast Wyoming have been undergoing a major mortality event owing to mountain pine beetle (Dendroctonus ponderosae) infestation since 2007. We studied biotic and abiotic drivers of growing season soil respiration in four mature stands experiencing different levels of mortality between 2008 and 2012 in the Medicine Bow Mountains, southeastern Wyoming, USA. For five years, beetle infestation significantly altered forest structure. Stand mortality was 30% and more than 80% in stands with the lowest and highest mortality, respectively. Understory vegetation cover increased by 50% for five years following beetle infestation. Needlefall was increased by more than 50% during first two years of beetle infestation compared to the pre-disturbance period. We did not observe an immediate increase in soil respiration following beetle infestation as suggested by some researchers. Soil respiration rates in midsummer ranged from 1.4 ± 0.1 μmol m-2 s-1 in stands with highest mortality to 3.1 ± 0.2 μmol m-2s-1 in uninfested stand. Live tree basal area was the dominant factor controlling soil respiration, explaining more than 60% of the interannual and spatial variations in response to the disturbance. In addition, soil respiration was significantly correlated with fine root biomass, which explained 55% of variations, providing strong evidence that autotrophic respiration dominated the forest soil respiration flux. Furthermore, the seasonality of soil respiration was controlled mainly by mean monthly precipitation and mid-day photosynthetically active radiation. Each factor predicted from 30% to 50% of seasonal soil respiration variability with the highest correlation coefficients in stand with the lowest mortality. Our results clearly indicate that the reduction of photosynthesis in trees over the infestation period significantly reduced soil respiration. The remaining activity in dead stands may

  20. The impact of global warming on germination and seedling emergence in Alliaria petiolata, a woodland species with dormancy loss dependent on low temperature.

    Science.gov (United States)

    Footitt, S; Huang, Z; Ölcer-Footitt, H; Clay, H; Finch-Savage, W E

    2018-03-23

    The impact of global warming on seed dormancy loss and germination was investigated in Alliaria petiolata (garlic mustard), a common woodland/hedgerow plant in Eurasia, considered invasive in North America. Increased temperature may have serious implications, since seeds of this species germinate and emerge at low temperatures early in spring to establish and grow before canopy development of competing species. Dormancy was evaluated in seeds buried in field soils. Seedling emergence was also investigated in the field, and in a thermogradient tunnel under global warming scenarios representing predicted UK air temperatures through to 2080. Dormancy was simple, and its relief required the accumulation of low temperature chilling time. Under a global warming scenario, dormancy relief and seedling emergence declined and seed mortality increased as soil temperature increased along a thermal gradient. Seedling emergence advanced with soil temperature, peaking 8 days earlier under 2080 conditions. The results indicate that as mean temperature increases due to global warming, the chilling requirement for dormancy relief may not be fully satisfied, but seedling emergence will continue from low dormancy seeds in the population. Adaptation resulting from selection of this low dormancy proportion is likely to reduce the overall population chilling requirement. Seedling emergence is also likely to keep pace with the advancement of biological spring, enabling A. petiolata to maintain its strategy of establishment before the woodland canopy closes. However, this potential for adaptation may be countered by increased seed mortality in the seed bank as soils warm. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.