Chemical ozone losses in Arctic and Antarctic polar winter/spring season derived from SCIAMACHY limb measurements 2002–2009

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T. Sonkaew

2013-02-01

Full Text Available Stratospheric ozone profiles are retrieved for the period 2002–2009 from SCIAMACHY measurements of limb-scattered solar radiation in the Hartley and Chappuis absorption bands of ozone. This data set is used to determine the chemical ozone losses in both the Arctic and Antarctic polar vortices by averaging the ozone in the vortex at a given potential temperature. The chemical ozone losses at isentropic levels between 450 K and 600 K are derived from the difference between observed ozone abundances and the ozone modelled taking diabatic cooling into account, but no chemical ozone loss. Chemical ozone losses of up to 30–40% between mid-January and the end of March inside the Arctic polar vortex are reported. Strong inter-annual variability of the Arctic ozone loss is observed, with the cold winters 2004/2005 and 2006/2007 showing chemical ozone losses inside the polar vortex at 475 K, where 1.7 ppmv and 1.4 ppmv of ozone were removed, respectively, over the period from 22 January to beginning of April and 0.9 ppmv and 1.2 ppmv, respectively, during February. For the winters of 2007/2008 and 2002/2003, ozone losses of about 0.8 ppmv and 0.4 ppmv, respectively are estimated at the 475 K isentropic level for the period from 22 January to beginning of April. Essentially no ozone losses were diagnosed for the relatively warm winters of 2003/2004 and 2005/2006. The maximum ozone loss in the SCIAMACHY data set was found in 2007 at the 600 K level and amounted to about 2.1 ppmv for the period between 22 January and the end of April. Enhanced losses close to this altitude were found in all investigated Arctic springs, in contrast to Antarctic spring. The inter-annual variability of ozone losses and PSC occurrence rates observed during Arctic spring is consistent with the known QBO effects on the Arctic polar vortex, with exception of the unusual Arctic winter 2008/2009.

The maximum total ozone mass loss of about 25 million tons was found in the

Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation

Science.gov (United States)

Meraner, Katharina; Schmidt, Hauke

2018-01-01

Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP) causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone decreases due to the indirect effect of EPP by about 10-15 % observed by satellite instruments. Here, we analyze the climate impact of winter boreal idealized polar mesospheric and polar stratospheric ozone losses as caused by EPP in the coupled Max Planck Institute Earth System Model (MPI-ESM). Using radiative transfer modeling, we find that the radiative forcing of mesospheric ozone loss during polar night is small. Hence, climate effects of mesospheric ozone loss due to energetic particles seem unlikely. Stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors

NARCIS (Netherlands)

Zee, van der R.; Gray, A.; Rijk, de T.C.

2015-01-01

This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various

Climate impact of idealized winter polar mesospheric and stratospheric ozone losses as caused by energetic particle precipitation

Directory of Open Access Journals (Sweden)

K. Meraner

2018-01-01

Full Text Available Energetic particles enter the polar atmosphere and enhance the production of nitrogen oxides and hydrogen oxides in the winter stratosphere and mesosphere. Both components are powerful ozone destroyers. Recently, it has been inferred from observations that the direct effect of energetic particle precipitation (EPP causes significant long-term mesospheric ozone variability. Satellites observe a decrease in mesospheric ozone up to 34 % between EPP maximum and EPP minimum. Stratospheric ozone decreases due to the indirect effect of EPP by about 10–15 % observed by satellite instruments. Here, we analyze the climate impact of winter boreal idealized polar mesospheric and polar stratospheric ozone losses as caused by EPP in the coupled Max Planck Institute Earth System Model (MPI-ESM. Using radiative transfer modeling, we find that the radiative forcing of mesospheric ozone loss during polar night is small. Hence, climate effects of mesospheric ozone loss due to energetic particles seem unlikely. Stratospheric ozone loss due to energetic particles warms the winter polar stratosphere and subsequently weakens the polar vortex. However, those changes are small, and few statistically significant changes in surface climate are found.

Effects of altitude and beehive bottom board type on wintering losses of honeybee colonies under subtropical climatic conditions

Energy Technology Data Exchange (ETDEWEB)

Ucak-Koc, A.

2014-06-01

The effects of altitude and beehive bottom board types (BBBT) on the wintering performance of honeybee colonies were investigated in the South Aegean Region of Turkey: Experiment I (E-I), with 32 colonies, in 2010-2011, and Experiment II (E-II), with 20 colonies, in 2011-2012. Each lowland (25 m) and highland (797 m) colony was divided randomly into two BBBT subgroups, open screen floor (OSF) and normal bottom floor (NBF), and wintered for about three months. In E-I, the local genotype Aegean ecotype of Anatolian bee (AE) and Italian race (ItR) were used, while in E-II, only the AE genotype was present. In E-I, the effect of wintering altitudes on the number of combs covered with bees (NCCB), and the effects of BBBT on brood area (BA) and the NCCB were found to be statistically significant (p < 0.05), but the effects of genotype on BA and NCCB were statistically insignificant (p > 0.05). In the E-II, the effect of wintering altitude on beehive weight was found to be statistically significant (p < 0.05), while its effect on the NCCB was statistically insignificant (p > 0.05). The wintering losses in the highland and lowland groups in E-I were determined to be 25% and 62.5% respectively. In contrast to this result, no loss was observed in E-II for both altitudes. In E-I, the wintering losses for both OSF and NBF groups were the same (43.75%). In conclusion, under subtropical climatic conditions, due to variations from year to year, honeybee colonies can be wintered more successfully in highland areas with OSF bottom board type. (Author)

High honey bee losses in the winter of 2016-2017 in Timiș county, Romania

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Daniela Marina Mot

2017-05-01

Full Text Available Beginning with November 2016 beekeepers from Timiș county reported bee colonies losses. During the winter months the situation became more the situation has become more severe, increasing losses of bee families. From November 2016, untill February 2017 were been received samples of dead bees from 23 different apiaries in Timiș county. The dead honey bees were analized in the way to discover what kind of causes produced all these losses. Was also proceeded to analyze the bacterial flora from bees intestine. Bacteriological examination of bees intestine and the cultivation on special medium of culture emphasized rich cultures of Paenibacillus larvae subsp. larvae (Bacillus larvae, etiologic agent for American foulbrood. These bacteria were been isolated from bee intestine in samples provided from 18 apiaries (78.26%. There are many causes of high degree of bee mortality in winter 2016-2017 but the isolation of Paenibacillus larvae subsp. larvae maybe was one of them.

Feed in summer, rest in winter: microbial carbon utilization in forest topsoil.

Science.gov (United States)

Žifčáková, Lucia; Větrovský, Tomáš; Lombard, Vincent; Henrissat, Bernard; Howe, Adina; Baldrian, Petr

2017-09-18

Evergreen coniferous forests contain high stocks of organic matter. Significant carbon transformations occur in litter and soil of these ecosystems, making them important for the global carbon cycle. Due to seasonal allocation of photosynthates to roots, carbon availability changes seasonally in the topsoil. The aim of this paper was to describe the seasonal differences in C source utilization and the involvement of various members of soil microbiome in this process. Here, we show that microorganisms in topsoil encode a diverse set of carbohydrate-active enzymes, including glycoside hydrolases and auxiliary enzymes. While the transcription of genes encoding enzymes degrading reserve compounds, such as starch or trehalose, was high in soil in winter, summer was characterized by high transcription of ligninolytic and cellulolytic enzymes produced mainly by fungi. Fungi strongly dominated the transcription in litter and an equal contribution of bacteria and fungi was found in soil. The turnover of fungal biomass appeared to be faster in summer than in winter, due to high activity of enzymes targeting its degradation, indicating fast growth in both litter and soil. In each enzyme family, hundreds to thousands of genes were typically transcribed simultaneously. Seasonal differences in the transcription of glycoside hydrolases and auxiliary enzyme genes are more pronounced in soil than in litter. Our results suggest that mainly fungi are involved in decomposition of recalcitrant biopolymers in summer, while bacteria replace them in this role in winter. Transcripts of genes encoding enzymes targeting plant biomass biopolymers, reserve compounds and fungal cell walls were especially abundant in the coniferous forest topsoil.

Hearing Loss due to Carbon Monoxide Poisoning

DEFF Research Database (Denmark)

Mehrparvar, Amir Houshang; Davari, Mohammad Hossein; Mollasadeghi, Abolfazl

2013-01-01

Carbon monoxide poisoning is one of the rare causes of hearing loss which may cause reversible or irreversible, unilateral or bilateral hearing loss after acute or chronic exposure. In this report, we present a case of bilateral sensorineural hearing loss in a secondary smelting workshop worker...... after an acute exposure to carbon monoxide. This complication was diagnosed by pure-tone audiometry and confirmed by transient evoked otoacoustic emissions. Hearing loss has not improved after 3 months of followup....

Major role of microbes in carbon fluxes during Austral winter in the Southern Drake Passage.

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Maura Manganelli

Full Text Available Carbon cycling in Southern Ocean is a major issue in climate change, hence the need to understand the role of biota in the regulation of carbon fixation and cycling. Southern Ocean is a heterogeneous system, characterized by a strong seasonality, due to long dark winter. Yet, currently little is known about biogeochemical dynamics during this season, particularly in the deeper part of the ocean. We studied bacterial communities and processes in summer and winter cruises in the southern Drake Passage. Here we show that in winter, when the primary production is greatly reduced, Bacteria and Archaea become the major producers of biogenic particles, at the expense of dissolved organic carbon drawdown. Heterotrophic production and chemoautotrophic CO(2 fixation rates were substantial, also in deep water, and bacterial populations were controlled by protists and viruses. A dynamic food web is also consistent with the observed temporal and spatial variations in archaeal and bacterial communities that might exploit various niches. Thus, Southern Ocean microbial loop may substantially maintain a wintertime food web and system respiration at the expense of summer produced DOC as well as regenerate nutrients and iron. Our findings have important implications for Southern Ocean ecosystem functioning and carbon cycle and its manipulation by iron enrichment to achieve net sequestration of atmospheric CO(2.

An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors

Science.gov (United States)

van der Zee, Romée; Gray, Alison; Pisa, Lennard; de Rijk, Theo

2015-01-01

This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1) Varroa destructor mite infestation rate in October 2011, (2) presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen), (3) presence of Brassica napus (oilseed rape) or Sinapis arvensis (wild mustard) pollen in bee bread in early August 2011, and (4) a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid. A novel feature of this work is its use of postal code random effects from two other independent datasets collected in the annual national monitoring by questionnaires of winter losses of honey bees in the Netherlands. These were used to plan the sample selection and also in the model fitting of the data in this study. It should however be noted that the results of the present pilot study are based on limited data, which may consequently reveal strong factors but fail to demonstrate possible interaction effects. PMID:26154346

An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors.

Directory of Open Access Journals (Sweden)

Romée van der Zee

Full Text Available This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1 Varroa destructor mite infestation rate in October 2011, (2 presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen, (3 presence of Brassica napus (oilseed rape or Sinapis arvensis (wild mustard pollen in bee bread in early August 2011, and (4 a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid. A novel feature of this work is its use of postal code random effects from two other independent datasets collected in the annual national monitoring by questionnaires of winter losses of honey bees in the Netherlands. These were used to plan the sample selection and also in the model fitting of the data in this study. It should however be noted that the results of the present pilot study are based on limited data, which may consequently reveal strong factors but fail to demonstrate possible interaction effects.

An Observational Study of Honey Bee Colony Winter Losses and Their Association with Varroa destructor, Neonicotinoids and Other Risk Factors.

Science.gov (United States)

van der Zee, Romée; Gray, Alison; Pisa, Lennard; de Rijk, Theo

2015-01-01

This article presents results of an analysis of honey bee losses over the winter of 2011-2012 in the Netherlands, from a sample of 86 colonies, located at 43 apiaries. The apiaries were selected using spatially stratified random sampling. Colony winter loss data were collected and related to various measures of colony strength recorded in summer, as well as data from laboratory analysis of sample material taken from two selected colonies in each of the 43 apiaries. The logistic regression model which best explained the risk of winter loss included, in order of statistical importance, the variables (1) Varroa destructor mite infestation rate in October 2011, (2) presence of the cyano-substituted neonicotinoids acetamiprid or thiacloprid in the first 2 weeks of August 2011 in at least one of the honey bee matrices honey, bees or bee bread (pollen), (3) presence of Brassica napus (oilseed rape) or Sinapis arvensis (wild mustard) pollen in bee bread in early August 2011, and (4) a measure of the unexplained winter losses for the postal code area where the colonies were located, obtained from a different dataset. We consider in the discussion that reduced opportunities for foraging in July and August because of bad weather may have added substantially to the adverse effects of acetamiprid and thiacloprid. A novel feature of this work is its use of postal code random effects from two other independent datasets collected in the annual national monitoring by questionnaires of winter losses of honey bees in the Netherlands. These were used to plan the sample selection and also in the model fitting of the data in this study. It should however be noted that the results of the present pilot study are based on limited data, which may consequently reveal strong factors but fail to demonstrate possible interaction effects.

Long-term carbon loss in fragmented Neotropical forests.

Science.gov (United States)

Pütz, Sandro; Groeneveld, Jürgen; Henle, Klaus; Knogge, Christoph; Martensen, Alexandre Camargo; Metz, Markus; Metzger, Jean Paul; Ribeiro, Milton Cezar; de Paula, Mateus Dantas; Huth, Andreas

2014-10-07

Tropical forests play an important role in the global carbon cycle, as they store a large amount of carbon (C). Tropical forest deforestation has been identified as a major source of CO2 emissions, though biomass loss due to fragmentation--the creation of additional forest edges--has been largely overlooked as an additional CO2 source. Here, through the combination of remote sensing and knowledge on ecological processes, we present long-term carbon loss estimates due to fragmentation of Neotropical forests: within 10 years the Brazilian Atlantic Forest has lost 69 (±14) Tg C, and the Amazon 599 (±120) Tg C due to fragmentation alone. For all tropical forests, we estimate emissions up to 0.2 Pg C y(-1) or 9 to 24% of the annual global C loss due to deforestation. In conclusion, tropical forest fragmentation increases carbon loss and should be accounted for when attempting to understand the role of vegetation in the global carbon balance.

Winter reduction in body mass in a very small, nonhibernating mammal: consequences for heat loss and metabolic rates.

Science.gov (United States)

Taylor, Jan R E; Rychlik, Leszek; Churchfield, Sara

2013-01-01

Low temperatures in northern winters are energetically challenging for mammals, and a special energetic burden is expected for diminutive species like shrews, which are among the smallest of mammals. Surprisingly, shrews shrink their body size in winter and reduce body and brain mass, an effect known as Dehnel's phenomenon, which is suggested to lower absolute energy intake requirements and thereby enhance survival when food availability is low. Yet reduced body size coupled with higher body-surface-to-mass ratio in these tiny mammals may result in thermoregulatory heat production at a given temperature constituting a larger proportion of the total energy expenditure. To evaluate energetic consequences of reduced body size in winter, we investigated common shrews Sorex araneus in northeastern Poland. Average body mass decreased by 19.0% from summer to winter, and mean skull depth decreased by 13.1%. There was no difference in Dehnel's phenomenon between years despite different weather conditions. The whole-animal thermal conductance (proportional to absolute heat loss) in shrews was 19% lower in winter than in summer; the difference between the two seasons remained significant after correcting for body mass and was caused by improved fur insulation in winter. Thermogenic capacity of shrews, although much enhanced in winter, did not reach its full potential of increase, and this corresponded with relatively mild subnivean temperatures. These findings indicate that, despite their small body size, shrews effectively decrease their costs of thermoregulation. The recorded decrease in body mass from summer to winter resulted in a reduction of overall resting metabolic rate (in thermoneutrality) by 18%. This, combined with the reduced heat loss, should translate to food requirements that are substantially lower than would be the case if shrews did not undergo seasonal decrease in body mass.

Assessment of winter wheat loss risk impacted by climate change from 1982 to 2011

Science.gov (United States)

Du, Xin

2017-04-01

The world's farmers will face increasing pressure to grow more food on less land in succeeding few decades, because it seems that the continuous population growth and agricultural products turning to biofuels would extend several decades into the future. Therefore, the increased demand for food supply worldwide calls for improved accuracy of crop productivity estimation and assessment of grain production loss risk. Extensive studies have been launched to evaluate the impacts of climate change on crop production based on various crop models drove with global or regional climate model (GCM/RCM) output. However, assessment of climate change impacts on agriculture productivity is plagued with uncertainties of the future climate change scenarios and complexity of crop model. Therefore, given uncertain climate conditions and a lack of model parameters, these methods are strictly limited in application. In this study, an empirical assessment approach for crop loss risk impacted by water stress has been established and used to evaluate the risk of winter wheat loss in China, United States, Germany, France and United Kingdom. The average value of winter wheat loss risk impacted by water stress for the three countries of Europe is about -931kg/ha, which is obviously higher in contrast with that in China (-570kg/ha) and in United States (-367kg/ha). Our study has important implications for further application of operational assessment of crop loss risk at a country or region scale. Future studies should focus on using higher spatial resolution remote sensing data, combining actual evapo-transpiration to estimate water stress, improving the method for downscaling of statistic crop yield data, and establishing much more rational and elaborate zoning method.

Annual measurements of gain and loss in aboveground carbon density

Science.gov (United States)

Baccini, A.; Walker, W. S.; Carvalho, L.; Farina, M.; Sulla-menashe, D. J.; Houghton, R. A.

2017-12-01

Tropical forests hold large stores of carbon, but their net carbon balance is uncertain. Land use and land-cover change (LULCC) are believed to release between 0.81 and 1.14 PgC yr-1, while intact native forests are thought to be a net carbon sink of approximately the same magnitude. Reducing the uncertainty of these estimates is not only fundamental to the advancement of carbon cycle science but is also of increasing relevance to national and international policies designed to reduce emissions from deforestation and forest degradation (e.g., REDD+). Contemporary approaches to estimating the net carbon balance of tropical forests rely on changes in forest area between two periods, typically derived from satellite data, together with information on average biomass density. These approaches tend to capture losses in biomass due to deforestation (i.e., wholesale stand removals) but are limited in their sensitivity to forest degradation (e.g., selective logging or single-tree removals), which can account for additional biomass losses on the order of 47-75% of deforestation. Furthermore, while satellite-based estimates of forest area loss have been used successfully to estimate associated carbon losses, few such analyses have endeavored to determine the rate of carbon sequestration in growing forests. Here we use 12 years (2003-2014) of pantropical satellite data to quantify net annual changes in the aboveground carbon density of woody vegetation (MgC ha-1yr-1), providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 Tg C yr-1. This net release of carbon consists of losses of 861.7 ± 80.2 Tg C yr-1 and gains of -436.5 ± 31.0 Tg C yr-1 . Gains result from forest growth; losses result from reductions in forest area due to deforestation and from reductions in biomass density within standing forests (degradation), with the latter accounting for 68.9% of overall losses. Our findings advance previous research

Hearing Loss due to Carbon Monoxide Poisoning

DEFF Research Database (Denmark)

Mehrparvar, Amir Houshang; Davari, Mohammad Hossein; Mollasadeghi, Abolfazl

2013-01-01

Carbon monoxide poisoning is one of the rare causes of hearing loss which may cause reversible or irreversible, unilateral or bilateral hearing loss after acute or chronic exposure. In this report, we present a case of bilateral sensorineural hearing loss in a secondary smelting workshop worker a...

Proton energy loss in multilayer graphene and carbon nanotubes

Science.gov (United States)

Uribe, Juan D.; Mery, Mario; Fierro, Bernardo; Cardoso-Gil, Raul; Abril, Isabel; Garcia-Molina, Rafael; Valdés, Jorge E.; Esaulov, Vladimir A.

2018-02-01

Results of a study of electronic energy loss of low keV protons interacting with multilayer graphene targets are presented. Proton energy loss shows an unexpectedly high value as compared with measurements in amorphous carbon and carbon nanotubes. Furthermore, we observe a classical linear behavior of the energy loss with the ion velocity but with an apparent velocity threshold around 0.1 a.u., which is not observed in other carbon allotropes. This suggests low dimensionality effects which can be due to the extraordinary graphene properties.

Modelling economic losses of historic and present-day high-impact winter storms in Switzerland

Science.gov (United States)

Welker, Christoph; Martius, Olivia; Stucki, Peter; Bresch, David; Dierer, Silke; Brönnimann, Stefan

2015-04-01

simulate the wind field and related economic impact of both historic and present-day high-impact winter storms in Switzerland since end of the 19th century. Our technique involves the dynamical downscaling of the 20CR to 3 km horizontal resolution using the numerical Weather Research and Forecasting model and the subsequent loss simulation using an open-source impact model. This impact model estimates, for modern economic and social conditions, storm-related economic losses at municipality level, and thus allows a numerical simulation of the impact from both historic and present-day severe winter storms in Switzerland on a relatively fine spatial scale. In this study, we apply the modelling chain to a storm sample of almost 90 high-impact winter storms in Switzerland since 1871, and we are thus able to make a statement of the typical wind and loss patterns of hazardous windstorms in Switzerland. To evaluate our modelling chain, we compare simulated storm losses with insurance loss data for the present-day windstorms "Lothar" and "Joachim" in December 1999 and December 2011, respectively. Our study further includes a range of sensitivity experiments and a discussion of the main sources of uncertainty.

Quantifying global soil carbon losses in response to warming.

Science.gov (United States)

Crowther, T W; Todd-Brown, K E O; Rowe, C W; Wieder, W R; Carey, J C; Machmuller, M B; Snoek, B L; Fang, S; Zhou, G; Allison, S D; Blair, J M; Bridgham, S D; Burton, A J; Carrillo, Y; Reich, P B; Clark, J S; Classen, A T; Dijkstra, F A; Elberling, B; Emmett, B A; Estiarte, M; Frey, S D; Guo, J; Harte, J; Jiang, L; Johnson, B R; Kröel-Dulay, G; Larsen, K S; Laudon, H; Lavallee, J M; Luo, Y; Lupascu, M; Ma, L N; Marhan, S; Michelsen, A; Mohan, J; Niu, S; Pendall, E; Peñuelas, J; Pfeifer-Meister, L; Poll, C; Reinsch, S; Reynolds, L L; Schmidt, I K; Sistla, S; Sokol, N W; Templer, P H; Treseder, K K; Welker, J M; Bradford, M A

2016-11-30

The majority of the Earth's terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ± 161 petagrams of carbon under one degree of warming, depending on the rate at which the effects of warming are realized. Under the conservative assumption that the response of soil carbon to warming occurs within a year, a business-as-usual climate scenario would drive the loss of 55 ± 50 petagrams of carbon from the upper soil horizons by 2050. This value is around 12-17 per cent of the expected anthropogenic emissions over this period. Despite the considerable uncertainty in our estimates, the direction of the global soil carbon response is consistent across all scenarios. This provides strong empirical support for the idea that rising temperatures will stimulate the net loss of soil carbon to the atmosphere, driving a positive land carbon-climate feedback that could accelerate climate change.

Carbon budgets for an irrigated intensively grazed dairy pasture and an unirrigated winter-grazed pasture

Science.gov (United States)

Hunt, John E.; Laubach, Johannes; Barthel, Matti; Fraser, Anitra; Phillips, Rebecca L.

2016-05-01

Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock grazing intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised and rotationally grazed dairy pasture and a neighbouring unirrigated, unfertilised, winter-grazed pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass carbon removed by grazing cows and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-grazing. Excreta deposition was calculated from animal feed intake. The intensively managed pasture gained C (NECB = 103 ± 42 g C m-2 yr-1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = -13 ± 23 g C m-2 yr-1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m-2 yr-1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m-2 yr-1). The ratio of GPP to the total annual water input of the irrigated pasture was 37 % greater than that of the unirrigated pasture, i.e. the former used the water input more efficiently than the latter to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of grazed grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.

Active summer carbon storage for winter persistence in trees at the cold alpine treeline.

Science.gov (United States)

Li, Mai-He; Jiang, Yong; Wang, Ao; Li, Xiaobin; Zhu, Wanze; Yan, Cai-Feng; Du, Zhong; Shi, Zheng; Lei, Jingpin; Schönbeck, Leonie; He, Peng; Yu, Fei-Hai; Wang, Xue

2018-03-12

The low-temperature limited alpine treeline is one of the most obvious boundaries in mountain landscapes. The question of whether resource limitation is the physiological mechanism for the formation of the alpine treeline is still waiting for conclusive evidence and answers. We therefore examined non-structural carbohydrates (NSC) and nitrogen (N) in treeline trees (TATs) and low-elevation trees (LETs) in both summer and winter in 11 alpine treeline cases ranging from subtropical monsoon to temperate continental climates across Eurasia. We found that tissue N concentration did not decrease with increasing elevation at the individual treeline level, but the mean root N concentration was lower in TATs than in LETs across treelines in summer. The TATs did not have lower tissue NSC concentrations than LETs in summer. However, the present study with multiple tree species across a large geographical scale, for the first time, revealed a common phenomenon that TATs had significantly lower NSC concentration in roots but not in the aboveground tissues than LETs in winter. Compared with LETs, TATs exhibited both a passive NSC storage in aboveground tissues in excess of carbon demand and an active starch storage in roots at the expense of growth reduction during the growing season. This starch accumulation disappeared in winter. Our results highlight some important aspects of the N and carbon physiology in relation to season in trees at their upper limits. Whether or to what extent the disadvantages of winter root NSC and summer root N level of TATs affect the growth of treeline trees and the alpine treeline formation needs to be further studied.

Soil-pit Method for Distribution and Leaching Loss of Nitrogen in Winter Wheat’s Soil, Weishan Irrigation District

Science.gov (United States)

Zhao, Erni; Xu, Lirong; Wang, Rongzhen

2018-01-01

Unreasonable application of irrigation and fertilizer will cause the waste of water and nitrogen and environmental pollution. In this paper, a series of soil-pit experiments were carried out to study the distribution and leaching loss of nitrogen in winter wheat’s soil. The results showed that NO3 - concentration at 20-80cm depth mainly responded to fertilizer application at the beginning of field experiment, but the amount of irrigation became the dominant factor with the growth of winter wheat. It is noteworthy that the distribution of NO3 - was mainly affected by the amount of fertilizer applied at the depth of 120-160cm in the whole period of growth of winter wheat. The accumulation position of NH4 + was deepened as the amount of irrigation increased, however, the maximum aggregation depth of ammonium nitrogen was no more than 80cm owing to its poor migration. It can be concluded that the influence of irrigation amount on the concentration of NH4 + in soil solution was more obvious than that of fertilizer. Compared with fertilizer, the amount of irrigation played a leading role in the utilization ratio of nitrogen and the yield of winter wheat. In summary, the best water and fertilizer treatment occurred in No.3 soil-pit, which meant that the middle amount of water and fertilizer could get higher wheat yield and less nitrogen leaching losses in the study area.

Carbon gains by conservation projects overbalance carbon losses by degradation in China's karst ecoregions

Science.gov (United States)

Tong, X.; Yue, Y.; Fensholt, R.; Brandt, M.

2017-12-01

China's ecological restoration projects are considered as "mega-engineering" activities and the most ambitious afforestation and conservation projects in human history. The highly sensitive and vulnerable karst ecosystem in Southwest China is one of the largest exposed carbonate rock areas (more than 0.54 million km2) in the world. Accelerating desertification has been reported during the last half century, caused by the increasing intensity of human exploitation of natural resources. As a result, vast karst areas (approximately 0.12 million km2) previously covered by vegetation and soil were turned into a rocky landscape. To combat this severe form of land degradation, more than 19 billion USD have been invested in mitigation initiatives since the end of the 1990s. The costs of mega-engineering as a climate change mitigation measure are however only justified if ecosystem properties can be affected at large scales. Here we study the carbon balance of the karst regions of 8 Chinese provinces over four decades, using optical and passive microwave satellite data, supported by statistical data on project implementations. We find that most areas experiencing losses in aboveground biomass carbon are located in areas with a high standing biomass ( 95 Mg C ha-1), whereas areas with a carbon gain are mostly located in regions with a low standing biomass ( 45 Mg C ha-1). However, the overall gains in carbon stocks overbalance the losses, with an average gross loss of -0.8 Pg C and a gross gain of +2.4 Pg C (1980s to 2016), resulting in a net gain of 1.6 Pg C. Areas of carbon gains are widespread and spatially coherent with conservation projects implemented after 2001, whereas areas of carbon losses show that ongoing degradation is still happening in the western parts of the karst regions. We conclude that the impact of conservation projects on the carbon balance of China's karst ecoregions is remarkable, but biomass carbon losses caused by ongoing degradation can not be

Winter honey bee colony losses, Varroa destructor control strategies, and the role of weather conditions: Results from a survey among beekeepers.

Science.gov (United States)

Beyer, Marco; Junk, Jürgen; Eickermann, Michael; Clermont, Antoine; Kraus, François; Georges, Carlo; Reichart, Andreas; Hoffmann, Lucien

2018-06-01

Sets of treatments that were applied against varroa mites in the Luxembourgish beekeeper community were surveyed annually with a questionnaire between the winters 2010/11 and 2014/15. The average temperature and the precipitation sum of the month, when the respective varroa control method was applied were considered as co-variables when evaluating the efficacy of varroa control regimes. Success or failure of control regimes was evaluated based on the percentage of colonies lost per apiary in the winter following the treatment(s). Neither a positive nor a negative effect of formic acid (concentration 60%, w/v) on the colony losses could be found, irrespective of the weather conditions around the time of application. The higher concentration of 85% formic acid was linked with reduced colony losses when applications were done in August. Colony losses were reduced when Thymovar was applied in July or August, but applications in September were associated with increased losses compared with apiaries not treated with Thymovar during the same period. Apilife application in July as well as Apivar applications between July and September were associated with reduced colony losses. The removal of the drone brood and trickled oxalic acid application had beneficial effects when being done in April and December, respectively. Relatively warm (3.0±1.3°C) and wet (507.0±38.6mm/2months) conditions during the winter months December and January and relatively cool (17.2±1.4°C average monthly temperature) and wet (110.8±55.5mm/month) conditions in July were associated with elevated honey bee colony losses. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sensorineural Hearing Loss following Carbon Monoxide Poisoning

Directory of Open Access Journals (Sweden)

Joseph P. Pillion

2012-01-01

Full Text Available A case study is presented of a 17-year-old male who sustained an anoxic brain injury and sensorineural hearing loss secondary to carbon monoxide poisoning. Audiological data is presented showing a slightly asymmetrical hearing loss of sensorineural origin and mild-to-severe degree for both ears. Word recognition performance was fair to poor bilaterally for speech presented at normal conversational levels in quiet. Management considerations of the hearing loss are discussed.

Deforestation and Carbon Stock Loss in Brazil's Amazonian Settlements.

Science.gov (United States)

Yanai, Aurora Miho; Nogueira, Euler Melo; de Alencastro Graça, Paulo Maurício Lima; Fearnside, Philip Martin

2017-03-01

We estimate deforestation and the carbon stock in 2740 (82 %) of the 3325 settlements in Brazil's Legal Amazonia region. Estimates are made both using available satellite data and a carbon map for the "pre-modern" period (prior to 1970). We used data from Brazil's Project for Monitoring Deforestation in Amazonia updated through 2013 and from the Brazilian Biomes Deforestation Monitoring Project (PMDBBS) updated through 2010. To obtain the pre-modern and recent carbon stocks we performed an intersection between a carbon map and a map derived from settlement boundaries and deforestation data. Although the settlements analyzed occupied only 8 % of Legal Amazonia, our results indicate that these settlements contributed 17 % (160,410 km 2 ) of total clearing (forest + non-forest) in Legal Amazonia (967,003 km 2 ). This represents a clear-cutting of 41 % of the original vegetation in the settlements. Out of this total, 72 % (115,634 km 2 ) was in the "Federal Settlement Project" (PA) category. Deforestation in settlements represents 20 % (2.6 Pg C) of the total carbon loss in Legal Amazonia (13.1 Pg C). The carbon stock in remaining vegetation represents 3.8 Pg C, or 6 % of the total remaining carbon stock in Legal Amazonia (58.6 Pg C) in the periods analyzed. The carbon reductions in settlements are caused both by the settlers and by external actors. Our findings suggest that agrarian reform policies contributed directly to carbon loss. Thus, the implementation of new settlements should consider potential carbon stock losses, especially if settlements are created in areas with high carbon stocks.

Contrasting effects of temperature and winter mixing on the seasonal and inter-annual variability of the carbonate system in the Northeast Atlantic Ocean

Directory of Open Access Journals (Sweden)

C. Dumousseaud

2010-05-01

Full Text Available Future climate change as a result of increasing atmospheric CO₂ concentrations is expected to strongly affect the oceans, with shallower winter mixing and consequent reduction in primary production and oceanic carbon drawdown in low and mid-latitudinal oceanic regions. Here we test this hypothesis by examining the effects of cold and warm winters on the carbonate system in the surface waters of the Northeast Atlantic Ocean for the period between 2005 and 2007. Monthly observations were made between the English Channel and the Bay of Biscay using a ship of opportunity program. During the colder winter of 2005/2006, the maximum depth of the mixed layer reached up to 650 m in the Bay of Biscay, whilst during the warmer (by 2.6 ± 0.5 °C winter of 2006/2007 the mixed layer depth reached only 300 m. The inter-annual differences in late winter concentrations of nitrate (2.8 ± 1.1 μmol l⁻¹ and dissolved inorganic carbon (22 ± 6 μmol kg⁻¹, with higher concentrations at the end of the colder winter (2005/2006, led to differences in the dissolved oxygen anomaly and the chlorophyll α-fluorescence data for the subsequent growing season. In contrast to model predictions, the calculated air-sea CO₂ fluxes (ranging from +3.7 to −4.8 mmol m⁻² d⁻¹ showed an increased oceanic CO₂ uptake in the Bay of Biscay following the warmer winter of 2006/2007 associated with wind speed and sea surface temperature differences.

Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey

Science.gov (United States)

Correia, A. C.; Costa-e-Silva, F.; Dubbert, M.; Piayda, A.; Pereira, J. S.

2016-10-01

Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity? We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP). The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation. Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can

Characterization and source apportionment of atmospheric organic and elemental carbon during fall and winter of 2003 in Xi'an, China

Directory of Open Access Journals (Sweden)

J. J. Cao

2005-01-01

Full Text Available Continuous measurements of atmospheric organic and elemental carbon (OC and EC were taken during the high-pollution fall and winter seasons at Xi'an, Shaanxi Province, China from September 2003 through February 2004. Battery-powered mini-volume samplers collected PM2.5 samples daily and PM10 samples every third day. Samples were also obtained from the plumes of residential coal combustion, motor-vehicle exhaust, and biomass burning sources. These samples were analyzed for OC/EC by thermal/optical reflectance (TOR following the Interagency Monitoring of Protected Visual Environments (IMPROVE protocol. OC and EC levels at Xi'an are higher than most urban cities in Asia. Average PM2.5 OC concentrations in fall and winter were 34.1±18.0 μg m−3 and 61.9±;33.2 μg m−3, respectively; while EC concentrations were 11.3±6.9 μg m−3 and 12.3±5.3 μg m−3, respectively. Most of the OC and EC were in the PM2.5 fraction. OC was strongly correlated (R>0.95 with EC in the autumn and moderately correlated (R=0.81 with EC during winter. Carbonaceous aerosol (OC×1.6+EC accounted for 48.8%±10.1% of the PM2.5 mass during fall and 45.9±7.5% during winter. The average OC/EC ratio was 3.3 in fall and 5.1 in winter, with individual OC/EC ratios nearly always exceeding 2.0. The higher wintertime OC/EC corresponded to increased residential coal combustion for heating. Total carbon (TC was associated with source contributions using absolute principal component analysis (APCA with eight thermally-derived carbon fractions. During fall, 73% of TC was attributed to gasoline engine exhaust, 23% to diesel exhaust, and 4% to biomass burning. During winter, 44% of TC was attributed to gasoline engine exhaust, 44% to coal burning, 9% to biomass burning, and 3% to diesel engine exhaust.

Stable carbon and oxygen isotope ratios of winter flounder otoliths assess connectivity between juvenile and adult habitats

Science.gov (United States)

Winter flounder populations (Pseudopleuronectes americanus) have significantly declined in recent years along the Rhode Island, USA coastline. The reasons for this decline are not completely clear; however, habitat loss may be a factor. Therefore, knowledge of connectivity betwee...

Root and soil carbon distribution at shoulderslope and footslope positions of temperate toposequences cropped to winter wheat

DEFF Research Database (Denmark)

Chirinda, Ngoni; Roncossek, Svenja Doreen; Heckrath, Goswin Johann

2014-01-01

Crop root residues are an important source of soil organic carbon (SOC) in arable systems. However, the spatial distribution of root biomass in arable systems remains largely unknown. In this study, we determined the spatial distribution of macro-root and shoot biomass of winter wheat at shoulder...

Subsidence and carbon loss in drained tropical peatlands

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A. Hooijer

2012-03-01

Full Text Available Conversion of tropical peatlands to agriculture leads to a release of carbon from previously stable, long-term storage, resulting in land subsidence that can be a surrogate measure of CO₂ emissions to the atmosphere. We present an analysis of recent large-scale subsidence monitoring studies in Acacia and oil palm plantations on peatland in SE Asia, and compare the findings with previous studies. Subsidence in the first 5 yr after drainage was found to be 142 cm, of which 75 cm occurred in the first year. After 5 yr, the subsidence rate in both plantation types, at average water table depths of 0.7 m, remained constant at around 5 cm yr⁻¹. The results confirm that primary consolidation contributed substantially to total subsidence only in the first year after drainage, that secondary consolidation was negligible, and that the amount of compaction was also much reduced within 5 yr. Over 5 yr after drainage, 75 % of cumulative subsidence was caused by peat oxidation, and after 18 yr this was 92 %. The average rate of carbon loss over the first 5 yr was 178 t CO_2eq ha⁻¹ yr⁻¹, which reduced to 73 t CO_2eq ha⁻¹ yr⁻¹ over subsequent years, potentially resulting in an average loss of 100 t CO_2eq ha⁻¹ yr⁻¹ over 25 yr. Part of the observed range in subsidence and carbon loss values is explained by differences in water table depth, but vegetation cover and other factors such as addition of fertilizers also influence peat oxidation. A relationship with groundwater table depth shows that subsidence and carbon loss are still considerable even at the highest water levels theoretically possible in plantations. This implies that improved plantation water management will reduce these impacts by 20 % at most, relative to current conditions, and that high rates of carbon loss and land subsidence are

The importance of rapid, disturbance-induced losses in carbon management and sequestration

Science.gov (United States)

Breshears, D.D.; Allen, Craig D.

2002-01-01

Management of terrestrial carbon fluxes is being proposed as a means of increasing the amount of carbon sequestered in the terrestrial biosphere. This approach is generally viewed only as an interim strategy for the coming decades while other longer-term strategies are developed and implemented — the most important being the direct reduction of carbon emissions. We are concerned that the potential for rapid, disturbance-induced losses may be much greater than is currently appreciated, especially by the decision-making community. Here we wish to: (1) highlight the complex and threshold-like nature of disturbances — such as fire and drought, as well as the erosion associated with each — that could lead to carbon losses; (2) note the global extent of ecosystems that are at risk of such disturbance-induced carbon losses; and (3) call for increased consideration of and research on the mechanisms by which large, rapid disturbance-induced losses of terrestrial carbon could occur. Our lack of ability as a scientific community to predict such ecosystem dynamics is precluding the effective consideration of these processes into strategies and policies related to carbon management and sequestration. Consequently, scientists need to do more to improve quantification of these potential losses and to integrate them into sound, sustainable policy options.

Carbon stock loss from deforestation through 2013 in Brazilian Amazonia.

Science.gov (United States)

Nogueira, Euler Melo; Yanai, Aurora M; Fonseca, Frederico O R; Fearnside, Philip Martin

2015-03-01

The largest carbon stock in tropical vegetation is in Brazilian Amazonia. In this ~5 million km(2) area, over 750,000 km(2) of forest and ~240,000 km(2) of nonforest vegetation types had been cleared through 2013. We estimate current carbon stocks and cumulative gross carbon loss from clearing of premodern vegetation in Brazil's 'Legal Amazonia' and 'Amazonia biome' regions. Biomass of 'premodern' vegetation (prior to major increases in disturbance beginning in the 1970s) was estimated by matching vegetation classes mapped at a scale of 1 : 250,000 and 29 biomass means from 41 published studies for vegetation types classified as forest (2317 1-ha plots) and as either nonforest or contact zones (1830 plots and subplots of varied size). Total biomass (above and below-ground, dry weight) underwent a gross reduction of 18.3% in Legal Amazonia (13.1 Pg C) and 16.7% in the Amazonia biome (11.2 Pg C) through 2013, excluding carbon loss from the effects of fragmentation, selective logging, fires, mortality induced by recent droughts and clearing of forest regrowth. In spite of the loss of carbon from clearing, large amounts of carbon were stored in stands of remaining vegetation in 2013, equivalent to 149 Mg C ha(-1) when weighted by the total area covered by each vegetation type in Legal Amazonia. Native vegetation in Legal Amazonia in 2013 originally contained 58.6 Pg C, while that in the Amazonia biome contained 56 Pg C. Emissions per unit area from clearing could potentially be larger in the future because previously cleared areas were mainly covered by vegetation with lower mean biomass than the remaining vegetation. Estimates of original biomass are essential for estimating losses to forest degradation. This study offers estimates of cumulative biomass loss, as well as estimates of premodern carbon stocks that have not been represented in recent estimates of deforestation impacts. © 2014 John Wiley & Sons Ltd.

Nitrous oxide and carbon dioxide emissions from monoculture and rotational cropping of corn, soybean and winter wheat

International Nuclear Information System (INIS)

Drury, C.F.; Yang, X.M.; Reynolds, W.D.; McLaughlin, N.B.

2008-01-01

Nitrous oxide (N 2 O) and carbon dioxide (CO 2 ) emissions from agricultural soils are influenced by different types of crops, the amounts and types of nitrogen fertilizers used, and the soil and climatic conditions under which the crops are grown. Crop rotation also has an impact on N 2 O emissions, as the crop residues used to supply soluble carbon to soil biota often differ from the crops being grown. This study compared the influence of crops and residues from preceding crops on N 2 O and CO 2 emissions from monoculture crops of soybeans, corn, and winter wheat at a site in Ontario. The phases of different rotations were compared with 2- and 3-year crop rotations. Results of the study showed that N 2 O emissions were approximately 3.1 to 5.1 times higher in monoculture corn than levels observed in winter wheat or soybean crops. When corn followed corn, average N 2 O emissions twice as high as when corn followed soybeans, and 65 per cent higher than when corn followed winter wheat. The higher levels of both N 2 O and CO 2 were attributed to higher inorganic nitrogen (N) application rates in corn crops. In the corn phase, CO 2 levels were higher when the preceding crop was winter wheat. It was concluded that N 2 O and CO 2 emissions from agricultural fields are influenced by both current and preceding crops, a fact which should be considered and accounted for in estimates and forecasts of agricultural greenhouse gas (GHG) emissions. 21 refs., 3 tabs., 10 figs

Nitrous oxide and carbon dioxide emissions from monoculture and rotational cropping of corn, soybean and winter wheat

Energy Technology Data Exchange (ETDEWEB)

Drury, C.F.; Yang, X.M.; Reynolds, W.D. [Agriculture and Agri-Food Canada, Harrow, ON (Canada); McLaughlin, N.B. [Agriculture and Agri-Food Canada, Ottawa, ON (Canada). Eastern Cereal and Oilseed Research Centre

2008-04-15

Nitrous oxide (N{sub 2}O) and carbon dioxide (CO{sub 2}) emissions from agricultural soils are influenced by different types of crops, the amounts and types of nitrogen fertilizers used, and the soil and climatic conditions under which the crops are grown. Crop rotation also has an impact on N{sub 2}O emissions, as the crop residues used to supply soluble carbon to soil biota often differ from the crops being grown. This study compared the influence of crops and residues from preceding crops on N{sub 2}O and CO{sub 2} emissions from monoculture crops of soybeans, corn, and winter wheat at a site in Ontario. The phases of different rotations were compared with 2- and 3-year crop rotations. Results of the study showed that N{sub 2}O emissions were approximately 3.1 to 5.1 times higher in monoculture corn than levels observed in winter wheat or soybean crops. When corn followed corn, average N{sub 2}O emissions twice as high as when corn followed soybeans, and 65 per cent higher than when corn followed winter wheat. The higher levels of both N{sub 2}O and CO{sub 2} were attributed to higher inorganic nitrogen (N) application rates in corn crops. In the corn phase, CO{sub 2} levels were higher when the preceding crop was winter wheat. It was concluded that N{sub 2}O and CO{sub 2} emissions from agricultural fields are influenced by both current and preceding crops, a fact which should be considered and accounted for in estimates and forecasts of agricultural greenhouse gas (GHG) emissions. 21 refs., 3 tabs., 10 figs.

Variability in carbon dioxide fluxes among six winter wheat paddocks managed under different tillage and grazing practices

Science.gov (United States)

Carbon dioxide (CO2) fluxes from six winter wheat (Triticum aestivum L.) paddocks (grain only, graze-grain, and graze-out) managed under conventional till (CT) and no-till (NT) systems were synthesized for the 2016-2017 growing season to compare the magnitudes and seasonal dynamics of CO2 fluxes and...

Winter wheat optimizes allocation in response to carbon limitation

Science.gov (United States)

Huang, Jianbei; Hammerbacher, Almuth; Trumbore, Susan; Hartmann, Henrik

2016-04-01

• Plant photosynthesis is not carbon-saturated at current atmospheric CO2 concentration ([CO2]) thus carbon allocation priority is of critical importance in determining plant response to environmental changes, including increasing [CO2]. • We quantified the percentage of daytime net assimilation (A) allocated to whole-plant nighttime respiration (R) and structural growth (SG), nonstructural carbohydrates (NSC) and secondary metabolites (SMs) during winter wheat (Triticum aestivum) vegetative growth (over 4 weeks) at glacial, ambient, and elevated [CO2] (170, 390 and 680 ppm). • We found that R/A remained relatively constant (11-14%) across [CO2] treatments, whereas plants allocated less C to growth and more C to export at low [CO2] than elevated [CO2]; low [CO2] grown plants tended to invest overall less C into NSC and SMs than to SG due to reduced NSC availability; while leaf SMs/NSC was greater at 170 ppm than at 680 ppm [CO2] this was the opposite for root SMs/NSC; biomass, especially NSC, were preferentially allocated to leaves instead of stems and roots, likely to relieve C limitation induced by low [CO2]. • We conclude that C limitation may force plants to reduce C allocation to long-term survival in order to secure short-term survival. Furthermore, they optimized allocation of the available resource by concentrating biomass and storage to those tissues responsible for assimilation.

Estimation of organic carbon loss potential in north of Iran

Science.gov (United States)

Shahriari, A.; Khormali, F.; Kehl, M.; Welp, G.; Scholz, Ch.

2009-04-01

The development of sustainable agricultural systems requires techniques that accurately monitor changes in the amount, nature and breakdown rate of soil organic matter and can compare the rate of breakdown of different plant or animal residues under different management systems. In this research, the study area includes the southern alluvial and piedmont plains of Gorgan River extended from east to west direction in Golestan province, Iran. Samples from 10 soil series and were collected from cultivation depth (0-30 cm). Permanganate-oxidizable carbon (POC) an index of soil labile carbon, was used to show soil potential loss of organic carbon. In this index shows the maximum loss of OC in a given soil. Maximum loss of OC for each soil series was estimated through POC and bulk density (BD). The potential loss of OC were estimated between 1253263 and 2410813 g/ha Carbon. Stable organic constituents in the soil include humic substances and other organic macromolecules that are intrinsically resistant against microbial attack, or that are physically protected by adsorption on mineral surfaces or entrapment within clay and mineral aggregates. However, the (Clay + Silt)/OC ratio had a negative significant (p < 0.001) correlation with POC content, confirming the preserving effect of fine particle.

Antarctic sea ice losses drive gains in benthic carbon drawdown.

Science.gov (United States)

Barnes, D K A

2015-09-21

Climate forcing of sea-ice losses from the Arctic and West Antarctic are blueing the poles. These losses are accelerating, reducing Earth's albedo and increasing heat absorption. Subarctic forest (area expansion and increased growth) and ice-shelf losses (resulting in new phytoplankton blooms which are eaten by benthos) are the only significant described negative feedbacks acting to counteract the effects of increasing CO2 on a warming planet, together accounting for uptake of ∼10(7) tonnes of carbon per year. Most sea-ice loss to date has occurred over polar continental shelves, which are richly, but patchily, colonised by benthic animals. Most polar benthos feeds on microscopic algae (phytoplankton), which has shown increased blooms coincident with sea-ice losses. Here, growth responses of Antarctic shelf benthos to sea-ice losses and phytoplankton increases were investigated. Analysis of two decades of benthic collections showed strong increases in annual production of shelf seabed carbon in West Antarctic bryozoans. These were calculated to have nearly doubled to >2x10(5) tonnes of carbon per year since the 1980s. Annual production of bryozoans is median within wider Antarctic benthos, so upscaling to include other benthos (combined study species typically constitute ∼3% benthic biomass) suggests an increased drawdown of ∼2.9x10(6) tonnes of carbon per year. This drawdown could become sequestration because polar continental shelves are typically deeper than most modern iceberg scouring, bacterial breakdown rates are slow, and benthos is easily buried. To date, most sea-ice losses have been Arctic, so, if hyperboreal benthos shows a similar increase in drawdown, polar continental shelves would represent Earth's largest negative feedback to climate change. Copyright © 2015 Elsevier Ltd. All rights reserved.

Controls on winter ecosystem respiration in temperate and boreal ecosystems

Science.gov (United States)

T. Wang; P. Ciais; S.L. Piao; C. Ottle; P. Brender; F. Maignan; A. Arain; A. Cescatti; D. Gianelle; C. Gough; L Gu; P. Lafleur; T. Laurila; B. Marcolla; H. Margolis; L. Montagnani; E. Moors; N. Saigusa; T. Vesala; G. Wohlfahrt; C. Koven; A. Black; E. Dellwik; A. Don; D. Hollinger; A. Knohl; R. Monson; J. Munger; A. Suyker; A. Varlagin; S. Verma

2011-01-01

Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal...

Quantifying soil carbon loss and uncertainty from a peatland wildfire using multi-temporal LiDAR

Science.gov (United States)

Reddy, Ashwan D.; Hawbaker, Todd J.; Wurster, F.; Zhu, Zhiliang; Ward, S.; Newcomb, Doug; Murray, R.

2015-01-01

Peatlands are a major reservoir of global soil carbon, yet account for just 3% of global land cover. Human impacts like draining can hinder the ability of peatlands to sequester carbon and expose their soils to fire under dry conditions. Estimating soil carbon loss from peat fires can be challenging due to uncertainty about pre-fire surface elevations. This study uses multi-temporal LiDAR to obtain pre- and post-fire elevations and estimate soil carbon loss caused by the 2011 Lateral West fire in the Great Dismal Swamp National Wildlife Refuge, VA, USA. We also determine how LiDAR elevation error affects uncertainty in our carbon loss estimate by randomly perturbing the LiDAR point elevations and recalculating elevation change and carbon loss, iterating this process 1000 times. We calculated a total loss using LiDAR of 1.10 Tg C across the 25 km2 burned area. The fire burned an average of 47 cm deep, equivalent to 44 kg C/m2, a value larger than the 1997 Indonesian peat fires (29 kg C/m2). Carbon loss via the First-Order Fire Effects Model (FOFEM) was estimated to be 0.06 Tg C. Propagating the LiDAR elevation error to the carbon loss estimates, we calculated a standard deviation of 0.00009 Tg C, equivalent to 0.008% of total carbon loss. We conclude that LiDAR elevation error is not a significant contributor to uncertainty in soil carbon loss under severe fire conditions with substantial peat consumption. However, uncertainties may be more substantial when soil elevation loss is of a similar or smaller magnitude than the reported LiDAR error.

Low-mass stars with mass loss and low-luminosity carbon star formation

International Nuclear Information System (INIS)

Boothroyd, A.I.

1987-01-01

The effects of large carbon enrichments in static stellar envelopes were investigated, using new Los Alamos opacities (including low-temperature carbon and molecular opacities) and including carbon ionizations. To search for the production of low-mass,low-luminosity carbon stars, detailed stellar evolutionary computations were carried out for a grid of low-mass stars of two different metallicities. The stars were evolved from the main sequence through all intermediate stages and through helium-shell flashes on the asymptotic giant branch. The effects of the latest nuclear reaction rates, the new Los Alamos opacities, Reimers-type wind mass loss, and detailed treatment of convection and semi-convection were investigated. Two low-luminosity carbon stars were achieved, in excellent agreement with observations. Conditions favoring dredge-up (and thus carbon-star production) include a reasonably large convective mixing length, low metallicity, relatively large envelope mass, and high flash strength. Mass loss was of major importance, tending to oppose dredge-up; the total mass-loss amounts inferred from observations suffice to prevent formation of high-mass, high-luminosity carbon stars

Determination of tropical deforestation rates and related carbon losses from 1990 to 2010.

Science.gov (United States)

Achard, Frédéric; Beuchle, René; Mayaux, Philippe; Stibig, Hans-Jürgen; Bodart, Catherine; Brink, Andreas; Carboni, Silvia; Desclée, Baudouin; Donnay, François; Eva, Hugh D; Lupi, Andrea; Raši, Rastislav; Seliger, Roman; Simonetti, Dario

2014-08-01

We estimate changes in forest cover (deforestation and forest regrowth) in the tropics for the two last decades (1990-2000 and 2000-2010) based on a sample of 4000 units of 10 ×10 km size. Forest cover is interpreted from satellite imagery at 30 × 30 m resolution. Forest cover changes are then combined with pan-tropical biomass maps to estimate carbon losses. We show that there was a gross loss of tropical forests of 8.0 million ha yr(-1) in the 1990s and 7.6 million ha yr(-1) in the 2000s (0.49% annual rate), with no statistically significant difference. Humid forests account for 64% of the total forest cover in 2010 and 54% of the net forest loss during second study decade. Losses of forest cover and Other Wooded Land (OWL) cover result in estimates of carbon losses which are similar for 1990s and 2000s at 887 MtC yr(-1) (range: 646-1238) and 880 MtC yr(-1) (range: 602-1237) respectively, with humid regions contributing two-thirds. The estimates of forest area changes have small statistical standard errors due to large sample size. We also reduce uncertainties of previous estimates of carbon losses and removals. Our estimates of forest area change are significantly lower as compared to national survey data. We reconcile recent low estimates of carbon emissions from tropical deforestation for early 2000s and show that carbon loss rates did not change between the two last decades. Carbon losses from deforestation represent circa 10% of Carbon emissions from fossil fuel combustion and cement production during the last decade (2000-2010). Our estimates of annual removals of carbon from forest regrowth at 115 MtC yr(-1) (range: 61-168) and 97 MtC yr(-1) (53-141) for the 1990s and 2000s respectively are five to fifteen times lower than earlier published estimates. © The Authors Global Change Biology Published by John Wiley & Sons Ltd.

Foliar photochemical processes and carbon metabolism under favourable and adverse winter conditions in a Mediterranean mixed forest, Catalonia (Spain)

Science.gov (United States)

Sperlich, D.; Chang, C. T.; Peñuelas, J.; Gracia, C.; Sabaté, S.

2014-10-01

Evergreen trees in the Mediterranean region must cope with a wide range of environmental stresses from summer drought to winter cold. The mildness of Mediterranean winters can periodically lead to favourable environmental conditions above the threshold for a positive carbon balance, benefitting evergreen woody species more than deciduous ones. The comparatively lower solar energy input in winter decreases the foliar light saturation point. This leads to a higher susceptibility to photoinhibitory stress especially when chilly (Arbutus unedo L.). Therefore, we collected twigs from the field during a period of mild winter conditions and after a sudden cold period. After both periods, the state of the photosynthetic machinery was tested in the laboratory by estimating the foliar photosynthetic potential with CO2 response curves in parallel with chlorophyll fluorescence measurements. The studied evergreen tree species benefited strongly from mild winter conditions by exhibiting extraordinarily high photosynthetic potentials. A sudden period of frost, however, negatively affected the photosynthetic apparatus, leading to significant decreases in key physiological parameters such as the maximum carboxylation velocity (Vc, max), the maximum photosynthetic electron transport rate (Jmax), and the optimal fluorometric quantum yield of photosystem II (Fv/Fm). The responses of Vc, max and Jmax were highly species specific, with Q. ilex exhibiting the highest and P. halepensis the lowest reductions. In contrast, the optimal fluorometric quantum yield of photosystem II (Fv/Fm) was significantly lower in A. unedo after the cold period. The leaf position played an important role in Q. ilex showing a stronger winter effect on sunlit leaves in comparison to shaded leaves. Our results generally agreed with the previous classifications of photoinhibition-tolerant (P. halepensis) and photoinhibition-avoiding (Q. ilex) species on the basis of their susceptibility to dynamic

Mitigating wildfire carbon loss in managed northern peatlands through restoration

Science.gov (United States)

Granath, Gustaf; Moore, Paul A.; Lukenbach, Maxwell C.; Waddington, James M.

2016-06-01

Northern peatlands can emit large amounts of carbon and harmful smoke pollution during a wildfire. Of particular concern are drained and mined peatlands, where management practices destabilize an array of ecohydrological feedbacks, moss traits and peat properties that moderate water and carbon losses in natural peatlands. Our results demonstrate that drained and mined peatlands in Canada and northern Europe can experience catastrophic deep burns (>200 t C ha-1 emitted) under current weather conditions. Furthermore, climate change will cause greater water losses in these peatlands and subject even deeper peat layers to wildfire combustion. However, the rewetting of drained peatlands and the restoration of mined peatlands can effectively lower the risk of these deep burns, especially if a new peat moss layer successfully establishes and raises peat moisture content. We argue that restoration efforts are a necessary measure to mitigate the risk of carbon loss in managed peatlands under climate change.

Estimated carbon emission from recent rapid forest loss in Southeast Asia

Science.gov (United States)

Chen, A.; Zeng, Z.; Peng, L.; Fei, S.

2017-12-01

Driven by agricultural expansion, industrial logging, oil palm and rubber plantations, and urbanization, Southeast Asia (SEA) is one of the hotspots for tropical deforestation over recent decades. The extent of the tropical SEA deforestation rate, as well as its impacts on carbon cycle and biodiversity, however, is still highly uncertain. In relevant work using high resolution global maps of the 21st-century forest cover, we find tropical SEA lost 22 million hectares, or 9%, of forest area during 2000-2014, a much higher deforestation rate than previously reported. Here we further conduct research investigating carbon emissions from tropical deforestation in SEA with satellite data of forest cover, a global tropical forest biomass map, and Earth system models. Preliminary results suggest that deforestation in SEA causes about 2.8 Tg C emissions to the atmosphere during the same period, also higher than that of previous studies. Meanwhile, carbon emission from deforestation shows high variations across different countries, topography and between the insular and maritime SEA. Indonesia and Malaysia tops in both total carbon loss and loss from per unit land area. Our results indicates that previous studies have underestimated the carbon loss due to deforestation in SEA. And until further effective forest conservation measures can be adopted, tropical SEA will continue playing a role of atmospheric carbon source in the coming decades.

N loss to drain flow and N2O emissions from a corn-soybean rotation with winter rye.

Science.gov (United States)

Gillette, K; Malone, R W; Kaspar, T C; Ma, L; Parkin, T B; Jaynes, D B; Fang, Q X; Hatfield, J L; Feyereisen, G W; Kersebaum, K C

2018-03-15

Anthropogenic perturbation of the global nitrogen cycle and its effects on the environment such as hypoxia in coastal regions and increased N 2 O emissions is of increasing, multi-disciplinary, worldwide concern, and agricultural production is a major contributor. Only limited studies, however, have simultaneously investigated NO 3 - losses to subsurface drain flow and N 2 O emissions under corn-soybean production. We used the Root Zone Water Quality Model (RZWQM) to evaluate NO 3 - losses to drain flow and N 2 O emissions in a corn-soybean system with a winter rye cover crop (CC) in central Iowa over a nine year period. The observed and simulated average drain flow N concentration reductions from CC were 60% and 54% compared to the no cover crop system (NCC). Average annual April through October cumulative observed and simulated N 2 O emissions (2004-2010) were 6.7 and 6.0kgN 2 O-Nha -1 yr -1 for NCC, and 6.2 and 7.2kgNha -1 for CC. In contrast to previous research, monthly N 2 O emissions were generally greatest when N loss to leaching were greatest, mostly because relatively high rainfall occurred during the months fertilizer was applied. N 2 O emission factors of 0.032 and 0.041 were estimated for NCC and CC using the tested model, which are similar to field results in the region. A local sensitivity analysis suggests that lower soil field capacity affects RZWQM simulations, which includes increased drain flow nitrate concentrations, increased N mineralization, and reduced soil water content. The results suggest that 1) RZWQM is a promising tool to estimate N 2 O emissions from subsurface drained corn-soybean rotations and to estimate the relative effects of a winter rye cover crop over a nine year period on nitrate loss to drain flow and 2) soil field capacity is an important parameter to model N mineralization and N loss to drain flow. Published by Elsevier B.V.

Gross primary production controls the subsequent winter CO2 exchange in a boreal peatland.

Science.gov (United States)

Zhao, Junbin; Peichl, Matthias; Öquist, Mats; Nilsson, Mats B

2016-12-01

In high-latitude regions, carbon dioxide (CO 2 ) emissions during the winter represent an important component of the annual ecosystem carbon budget; however, the mechanisms that control the winter CO 2 emissions are currently not well understood. It has been suggested that substrate availability from soil labile carbon pools is a main driver of winter CO 2 emissions. In ecosystems that are dominated by annual herbaceous plants, much of the biomass produced during the summer is likely to contribute to the soil labile carbon pool through litter fall and root senescence in the autumn. Thus, the summer carbon uptake in the ecosystem may have a significant influence on the subsequent winter CO 2 emissions. To test this hypothesis, we conducted a plot-scale shading experiment in a boreal peatland to reduce the gross primary production (GPP) during the growing season. At the growing season peak, vascular plant biomass in the shaded plots was half that in the control plots. During the subsequent winter, the mean CO 2 emission rates were 21% lower in the shaded plots than in the control plots. In addition, long-term (2001-2012) eddy covariance data from the same site showed a strong correlation between the GPP (particularly the late summer and autumn GPP) and the subsequent winter net ecosystem CO 2 exchange (NEE). In contrast, abiotic factors during the winter could not explain the interannual variation in the cumulative winter NEE. Our study demonstrates the presence of a cross-seasonal link between the growing season biotic processes and winter CO 2 emissions, which has important implications for predicting winter CO 2 emission dynamics in response to future climate change. © 2016 John Wiley & Sons Ltd.

Assessing the ratio of leaf carbon to nitrogen in winter wheat and spring barley based on hyperspectral data

Science.gov (United States)

Xu, Xin-gang; Gu, Xiao-he; Song, Xiao-yu; Xu, Bo; Yu, Hai-yang; Yang, Gui-jun; Feng, Hai-kuan

2016-10-01

The metabolic status of carbon (C) and nitrogen (N) as two essential elements of crop plants has significant influence on the ultimate formation of yield and quality in crop production. The ratio of carbon to nitrogen (C/N) from crop leaves, defined as ratio of LCC (leaf carbon concentration) to LNC (leaf nitrogen concentration), is an important index that can be used to diagnose the balance between carbon and nitrogen, nutrient status, growth vigor and disease resistance in crop plants. Thus, it is very significant for effectively evaluating crop growth in field to monitor changes of leaf C/N quickly and accurately. In this study, some typical indices aimed at N estimation and chlorophyll evaluation were tested to assess leaf C/N in winter wheat and spring barley. The multi-temporal hyperspectral measurements from the flag-leaf, anthesis, filling, and milk-ripe stages were used to extract these selected spectral indices to estimate leaf C/N in wheat and barley. The analyses showed that some tested indices such as MTCI, MCARI/OSAVI2, and R-M had the better performance of assessing C/N for both of crops. Besides, a mathematic algorithm, Branch-and-Bound (BB) method was coupled with the spectral indices to assess leaf C/N in wheat and barley, and yielded the R2 values of 0.795 for winter wheat, R2 of 0.727 for spring barley, 0.788 for both crops combined. It demonstrates that using hyperspectral data has a good potential for remote assessment of leaf C/N in crops.

Response of vegetation to carbon dioxide - effect of elevated levels of CO{sub 2} on winter wheat under two moisture regimes

Energy Technology Data Exchange (ETDEWEB)

Chaudhuri, U.N.; Burnett, R.B.; Kanemasu, E.T.; Kirkham, M.B.

1987-12-31

This report deals with the second-year (1985-86) findings of an on going experiment with winter wheat (Triticum aestivum L.) at different carbon dioxide (CO{sub 2}) levels and under two moisture regimes. The results for the first year are given in the U.S. Department of Energy, Carbon Dioxide Research Division Response of Vegetation to Carbon Dioxide. The purpose of the second year`s experiment was to verify the results of 1984-85. However, based on the performance and the results of 1984-85 experiments, a few modifications were made.

Wet scavenging of organic and elemental carbon during summer monsoon and winter monsoon seasons

Science.gov (United States)

Sonwani, S.; Kulshrestha, U. C.

2017-12-01

In the era of rapid industrialization and urbanization, atmospheric abundance of carbonaceous aerosols is increasing due to more and more fossil fuel consumption. Increasing levels of carbonaceous content have significant adverse effects on air quality, human health and climate. The present study was carried out at Delhi covering summer monsoon (July -Sept) and winter monsoon (Dec-Jan) seasons as wind and other meteorological factors affect chemical composition of precipitation in different manner. During the study, the rainwater and PM10 aerosols were collected in order to understand the scavenging process of elemental and organic carbon. The Rain water samples were collected on event basis. PM10 samples were collected before rain (PR), during rain (DR) and after rain (AR) during 2016-2017. The collected samples were analysed by the thermal-optical reflectance method using IMPROVE-A protocol. In PM10, the levels of organic carbon (OC) and its fractions (OC1, OC2, OC3 and OC4) were found significantly lower in the AR samples as compared to PR and DR samples. A significant positive correlation was noticed between scavenging ratios of organic carbon and rain intensity indicating an efficient wet removal of OC. In contrast to OCs, the levels of elemental carbon and its fractions (EC1, EC2, and EC3) in AR were not distinct during PR and DR. The elemental carbon showed very week correlation with rain intensity in Delhi region which could be explained on the basis of hydrophobic nature of freshly emitted carbon soot. The detailed results will be discussed during the conference.

Rotor losses in laminated magnets and an anisotropic carbon fiber sleeve

NARCIS (Netherlands)

Van der Geest, M.; Wolmarans, J.J.; Polinder, H.; Ferreira, J.A.; Zeilstra, D.

2012-01-01

High speed fault tolerant permanent magnet machines have strong asynchronous airgap harmonics, making them susceptible to rotor eddy-current losses. These losses can be reduced by using novel high resistivity materials like plastic bonded magnets and carbon fiber reinforced retaining sleeves. This

Straw export in continuous winter wheat and the ability of oil radish catch crops and early sowing of wheat to offset soil C and N losses: A simulation study

DEFF Research Database (Denmark)

Peltre, Clément; Nielsen, M; Christensen, Bent Tolstrup

2016-01-01

The export of winter wheat straw for bioenergy may reduce soil C stocks and affect N losses. Establishing fast-growing catch crops between successive wheat crops could potentially offset some of the C and N losses. Another option is to sow wheat earlier, increasing biomass production during...... the autumn. The effects of straw export, oil radish catch crop and early sowing of wheat on soil C storage, N leaching losses and N2O emissions were simulated by applying the Daisy model to winter wheat grown continuously for a period of 100 years on a sandy loam soil in a Danish climate. The simulations....... Inclusion of the oil radish catch crop could offset this loss by 2–3 percentage points. Earlier sowing of wheat increased straw production by 18% and reduced loss of soil C by 3–5 percentage points compared to normal sowing time with full straw export. Catch crops and early sowing also reduced N...

Contrasting vulnerability of drained tropical and high-latitude peatlands to fluvial loss of stored carbon

Science.gov (United States)

Evans, Chris D.; Page, Susan E.; Jones, Tim; Moore, Sam; Gauci, Vincent; Laiho, Raija; Hruška, Jakub; Allott, Tim E. H.; Billett, Michael F.; Tipping, Ed; Freeman, Chris; Garnett, Mark H.

2014-11-01

Carbon sequestration and storage in peatlands rely on consistently high water tables. Anthropogenic pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of pressures including drainage, burning, land conversion for agriculture, timber, and biofuel production, cause loss of peat-forming vegetation and exposure of previously anaerobic peat to aerobic decomposition. This can shift peatlands from net CO2 sinks to large CO2 sources, releasing carbon held for millennia. Peatlands also export significant quantities of carbon via fluvial pathways, mainly as dissolved organic carbon (DOC). We analyzed radiocarbon (14C) levels of DOC in drainage water from multiple peatlands in Europe and Southeast Asia, to infer differences in the age of carbon lost from intact and drained systems. In most cases, drainage led to increased release of older carbon from the peat profile but with marked differences related to peat type. Very low DOC-14C levels in runoff from drained tropical peatlands indicate loss of very old (centuries to millennia) stored peat carbon. High-latitude peatlands appear more resilient to drainage; 14C measurements from UK blanket bogs suggest that exported DOC remains young (use changes in the tropics. Data from the UK Peak District, an area where air pollution and intensive land management have triggered Sphagnum loss and peat erosion, suggest that additional anthropogenic pressures may trigger fluvial loss of much older (>500 year) carbon in high-latitude systems. Rewetting at least partially offsets drainage effects on DOC age.

Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses.

Science.gov (United States)

S. R. Saleska; S. D. Miller; D. M. Matross; M. L. Goulden; S. C. Wofsy; H. R. da Rocha; P. B. de Camargo; P. Crill; B. C. Daube; H. C. de Freitas; L. Hutyra; M. Keller; V. Kirchhoff; M. Menton; J. W. Munger; H. E. Pyle; A. H. Rice; H. Silva

2003-01-01

The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.3 (confidence...

Comparing soil carbon loss through respiration and leaching under extreme precipitation events in arid and semiarid grasslands

Science.gov (United States)

Liu, Ting; Wang, Liang; Feng, Xiaojuan; Zhang, Jinbo; Ma, Tian; Wang, Xin; Liu, Zongguang

2018-03-01

Respiration and leaching are two main processes responsible for soil carbon loss. While the former has received considerable research attention, studies examining leaching processes are limited, especially in semiarid grasslands due to low precipitation. Climate change may increase the extreme precipitation event (EPE) frequency in arid and semiarid regions, potentially enhancing soil carbon loss through leaching and respiration. Here we incubated soil columns of three typical grassland soils from Inner Mongolia and the Qinghai-Tibetan Plateau and examined the effect of simulated EPEs on soil carbon loss through respiration and leaching. EPEs induced a transient increase in CO2 release through soil respiration, equivalent to 32 and 72 % of the net ecosystem productivity (NEP) in the temperate grasslands (Xilinhot and Keqi) and 7 % of NEP in the alpine grasslands (Gangcha). By comparison, leaching loss of soil carbon accounted for 290, 120, and 15 % of NEP at the corresponding sites, respectively, with dissolved inorganic carbon (DIC, biogenic DIC + lithogenic DIC) as the main form of carbon loss in the alkaline soils. Moreover, DIC loss increased with recurring EPEs in the soil with the highest pH due to an elevated contribution of dissolved CO2 from organic carbon degradation (indicated by DIC-δ13C). These results highlight the fact that leaching loss of soil carbon (particularly in the form of DIC) is important in the regional carbon budget of arid and semiarid grasslands and also imply that SOC mineralization in alkaline soils might be underestimated if only measured as CO2 emission from soils into the atmosphere. With a projected increase in EPEs under climate change, soil carbon leaching processes and the influencing factors warrant a better understanding and should be incorporated into soil carbon models when estimating carbon balance in grassland ecosystems.

Comparing soil carbon loss through respiration and leaching under extreme precipitation events in arid and semiarid grasslands

Directory of Open Access Journals (Sweden)

T. Liu

2018-03-01

Full Text Available Respiration and leaching are two main processes responsible for soil carbon loss. While the former has received considerable research attention, studies examining leaching processes are limited, especially in semiarid grasslands due to low precipitation. Climate change may increase the extreme precipitation event (EPE frequency in arid and semiarid regions, potentially enhancing soil carbon loss through leaching and respiration. Here we incubated soil columns of three typical grassland soils from Inner Mongolia and the Qinghai–Tibetan Plateau and examined the effect of simulated EPEs on soil carbon loss through respiration and leaching. EPEs induced a transient increase in CO2 release through soil respiration, equivalent to 32 and 72 % of the net ecosystem productivity (NEP in the temperate grasslands (Xilinhot and Keqi and 7 % of NEP in the alpine grasslands (Gangcha. By comparison, leaching loss of soil carbon accounted for 290, 120, and 15 % of NEP at the corresponding sites, respectively, with dissolved inorganic carbon (DIC, biogenic DIC + lithogenic DIC as the main form of carbon loss in the alkaline soils. Moreover, DIC loss increased with recurring EPEs in the soil with the highest pH due to an elevated contribution of dissolved CO2 from organic carbon degradation (indicated by DIC-δ13C. These results highlight the fact that leaching loss of soil carbon (particularly in the form of DIC is important in the regional carbon budget of arid and semiarid grasslands and also imply that SOC mineralization in alkaline soils might be underestimated if only measured as CO2 emission from soils into the atmosphere. With a projected increase in EPEs under climate change, soil carbon leaching processes and the influencing factors warrant a better understanding and should be incorporated into soil carbon models when estimating carbon balance in grassland ecosystems.

Understanding the driving forces behind the losses of soil carbon across England and Wales

Science.gov (United States)

Bellamy, Patricia

2010-05-01

More than twice as much carbon is held in soils as in vegetation or the atmosphere, and changes in soil carbon content can have a large effect on the global carbon budget. The possibility that climate change is being reinforced by increased carbon dioxide emissions from soils owing to rising temperature is the subject of a continuing debate. But evidence for the suggested feedback mechanism has to date come solely from small-scale laboratory and field experiments and modelling studies. Here we use data from the National Soil Inventory of England and Wales obtained between 1978 and 2003 to show that carbon was lost from soils across England and Wales over the survey period at a mean rate of 0.6% yr-1 (relative to the existing soil carbon content). We find that the relative rate of carbon loss increased with soil carbon content and was more than 2% yr-1 in soils with carbon contents greater than 100 g kg-1. The relationship between rate of carbon loss and carbon content is irrespective of land use, suggesting a link to climate change. Our findings indicate that losses of soil carbon in England and Wales—and by inference in other temperate regions—are likely to have been offsetting absorption of carbon by terrestrial sinks. To investigate the possible driving forces of the measured losses of soil carbon we applied a simple model of soil carbon turnover to evaluate alternative explanations for the observed trends. We find that neither changes in decomposition resulting from the effects of climate change on soil temperature and moisture, nor changes in carbon input from vegetation, could account on their own for the overall trends. Of other explanations, results indicate that past changes in land use and management were probably dominant. The climate change signal, such as it is, is masked by these other changes. A more sophisticated model of carbon change (DAYCENT) has now been applied across the whole range of soils in England and Wales. This model has been

Dynamics of organic carbon losses by water erosion after biocrust removal

Directory of Open Access Journals (Sweden)

Cantón Yolanda

2014-12-01

Full Text Available In arid and semiarid ecosystems, plant interspaces are frequently covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts. These crusts often act as runoff sources and are involved in soil stabilization and fertility, as they prevent erosion by water and wind, fix atmospheric C and N and contribute large amounts of C to soil. Their contribution to the C balance as photosynthetically active surfaces in arid and semiarid regions is receiving growing attention. However, very few studies have explicitly evaluated their contribution to organic carbon (OC lost from runoff and erosion, which is necessary to ascertain the role of biocrusts in the ecosystem C balance. Furthermore, biocrusts are not resilient to physical disturbances, which generally cause the loss of the biocrust and thus, an increase in runoff and erosion, dust emissions, and sediment and nutrient losses. The aim of this study was to find out the influence of biocrusts and their removal on dissolved and sediment organic carbon losses. One-hour extreme rainfall simulations (50 mm h-1 were performed on small plots set up on physical soil crusts and three types of biocrusts, representing a development gradient, and also on plots where these crusts were removed from. Runoff and erosion rates, dissolved organic carbon (DOC and organic carbon bonded to sediments (SdOC were measured during the simulated rain. Our results showed different SdOC and DOC for the different biocrusts and also that the presence of biocrusts substantially decreased total organic carbon (TOC (average 1.80±1.86 g m-2 compared to physical soil crusts (7.83±3.27 g m-2. Within biocrusts, TOC losses decreased as biocrusts developed, and erosion rates were lower. Thus, erosion drove TOC losses while no significant direct relationships were found between TOC losses and runoff. In both physical crusts and biocrusts, DOC and SdOC concentrations were higher during the first minutes after runoff

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

Directory of Open Access Journals (Sweden)

Andrea Damm

2017-08-01

Under +2 °C warming, the weather-induced risk of losses in winter overnight stays related to skiing tourism in Europe amounts to up to 10.1 million nights per winter season, which is +7.3 million overnight stays additionally at risk compared to the reference period (1971–2000. Among the top four European skiing tourism nations – Austria, France, Italy and Switzerland – France and Switzerland show the lowest increase in risk of losses in winter overnight stays. The highest weather-induced risk of losses in winter overnight stays – in the reference period as well as in the +2 °C scenarios – is found in Austria, followed by Italy. These two countries account for the largest fraction of winter overnight stays in skiing related NUTS-3 regions.

Contribution of Soil Fauna to Foliar Litter-Mass Loss in Winter in an Ecotone between Dry Valley and Montane Forest in the Upper Reaches of the Minjiang River.

Science.gov (United States)

Peng, Yan; Yang, Wanqin; Li, Jun; Wang, Bin; Zhang, Chuan; Yue, Kai; Wu, Fuzhong

2015-01-01

Litter decomposition during winter can provide essential nutrients for plant growth in the subsequent growing season, which plays important role in preventing the expansion of dry areas and maintaining the stability of ecotone ecosystems. However, limited information is currently available on the contributions of soil fauna to litter decomposition during winter in such ecosystems. Therefore, a field experiment that included litterbags with two different mesh sizes (0.04 mm and 3 mm) was conducted to investigate the contribution of soil fauna to the loss of foliar litter mass in winter from November 2013 to April 2014 along the upper reaches of the Minjiang River. Two litter types of the dominant species were selected in each ecosystem: cypress (Cupressus chengiana) and oak (Quercus baronii) in ecotone; cypress (Cupressus chengiana) and clovershrub (Campylotropis macrocarpa) in dry valley; and fir (Abies faxoniana) and birch (Betula albosinensis) in montane forest. Over one winter incubation, foliar litter lost 6.0%-16.1%, 11.4%-26.0%, and 6.4%-8.5% of initial mass in the ecotone, dry valley and montane forest, respectively. Soil fauna showed obvious contributions to the loss of foliar litter mass in all of the ecosystems. The highest contribution (48.5%-56.8%) was observed in the ecotone, and the lowest contribution (0.4%-25.8%) was observed in the montane forest. Compared with other winter periods, thawing period exhibited higher soil fauna contributions to litter mass loss in ecotone and dry valley, but both thawing period and freezing period displayed higher soil fauna contributions in montane forest. Statistical analysis demonstrated that the contribution of soil fauna was significantly correlated with temperature and soil moisture during the winter-long incubation. These results suggest that temperature might be the primary control factor in foliar litter decomposition, but more active soil fauna in the ecotone could contribute more in litter decomposition and

Contribution of Soil Fauna to Foliar Litter-Mass Loss in Winter in an Ecotone between Dry Valley and Montane Forest in the Upper Reaches of the Minjiang River.

Directory of Open Access Journals (Sweden)

Yan Peng

Full Text Available Litter decomposition during winter can provide essential nutrients for plant growth in the subsequent growing season, which plays important role in preventing the expansion of dry areas and maintaining the stability of ecotone ecosystems. However, limited information is currently available on the contributions of soil fauna to litter decomposition during winter in such ecosystems. Therefore, a field experiment that included litterbags with two different mesh sizes (0.04 mm and 3 mm was conducted to investigate the contribution of soil fauna to the loss of foliar litter mass in winter from November 2013 to April 2014 along the upper reaches of the Minjiang River. Two litter types of the dominant species were selected in each ecosystem: cypress (Cupressus chengiana and oak (Quercus baronii in ecotone; cypress (Cupressus chengiana and clovershrub (Campylotropis macrocarpa in dry valley; and fir (Abies faxoniana and birch (Betula albosinensis in montane forest. Over one winter incubation, foliar litter lost 6.0%-16.1%, 11.4%-26.0%, and 6.4%-8.5% of initial mass in the ecotone, dry valley and montane forest, respectively. Soil fauna showed obvious contributions to the loss of foliar litter mass in all of the ecosystems. The highest contribution (48.5%-56.8% was observed in the ecotone, and the lowest contribution (0.4%-25.8% was observed in the montane forest. Compared with other winter periods, thawing period exhibited higher soil fauna contributions to litter mass loss in ecotone and dry valley, but both thawing period and freezing period displayed higher soil fauna contributions in montane forest. Statistical analysis demonstrated that the contribution of soil fauna was significantly correlated with temperature and soil moisture during the winter-long incubation. These results suggest that temperature might be the primary control factor in foliar litter decomposition, but more active soil fauna in the ecotone could contribute more in litter

Tropical forests are a net carbon source based on aboveground measurements of gain and loss

Science.gov (United States)

Baccini, A.; Walker, W.; Carvalho, L.; Farina, M.; Sulla-Menashe, D.; Houghton, R. A.

2017-10-01

The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world’s tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year-1). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year-1 and gains of 436.5 ± 31.0 Tg C year-1. Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses.

Organic loss in drained wetland: managing the carbon footprint

NARCIS (Netherlands)

Durham, B.; van de Noort, R.; Martens, V.V.; Vorenhout, M.

2012-01-01

The recent installation of land drains at Star Carr, Yorkshire, UK, has been linked with loss of preservation quality in this important Mesolithic buried landscape, challenging the PARIS principle. Historically captured organic carbon, including organic artefacts, is being converted to soluble

Terrestrial carbon losses from mountaintop coal mining offset regional forest carbon sequestration in the 21st century

International Nuclear Information System (INIS)

Elliott Campbell, J; Fox, James F; Acton, Peter M

2012-01-01

Studies that quantify the spatial and temporal variability of carbon sources and sinks provide process-level information for the prediction of future levels of atmospheric carbon dioxide as well as verification of current emission agreements. Assessments of carbon sources and sinks for North America that compare top-down atmospheric constraints with bottom-up inventories find particularly large carbon sinks in the southeastern US. However, this southeastern US sink may be impacted by extreme land-use disturbance events due to mountaintop coal mining (MCM). Here we apply ecosystem modeling and field experiment data to quantify the potential impact of future mountaintop coal mining on the carbon budget of the southern Appalachian forest region. For projections based on historical mining rates, grassland reclamation, and the continued regrowth of un-mined forests, we find that the southern Appalachian forests switch from a net carbon sink to a net carbon source by year 2025–33 with a 30%–35% loss in terrestrial carbon stocks relative to a scenario with no future mining by the year 2100. Alternatively, scenarios of forest sequestration due to the effect of CO 2 fertilization result in a 15%–24% loss in terrestrial carbon stocks by the year 2100 for mining scenarios relative to scenarios with no future mining. These results suggest that while power plant stack emissions are the dominant life-cycle stage in coal-fired electricity, accounting for mountaintop coal mining in bottom-up inventories may be a critical component of regional carbon budgets. (letter)

Life Cycle Assessment on Carbon Footprint of Winter Wheat-Summer Maize Cropping System Based on Survey Data of Gaomi in Shandong Province, China

Directory of Open Access Journals (Sweden)

ZHU Yong-chang

2017-08-01

Full Text Available Grain production can generate huge amount of greenhouse gases through raw material production and energy comsumption, nitrogen fertilizer amendment and farming machinery operation. Based questionnaire survey of raw material inputs and management of wheat-maize cropping system in Gaomi, Shandong Province, carbon footprint of grain production was calculated using life cycle assessment methodology. Carbon footprint per unit area of wheat, maize, and winter wheat-summer maize cropping system were 5 183.33, 3 778.09 kg CO2-eq·hm-2 and 8 961.42 kg CO2-eq·hm-2, carbon footprint per unit grain yield were 0.69, 0.40 kg CO2-eq·kg-1 and 0.53 kg CO2-eq·kg-1, carbon footprint per unit net present value were 1.82, 0.40 kg CO2-eq·yuan-1 and 0.44 kg CO2-eq·yuan-1, respectively. Greenhouse gas(GHG emission of winter wheat-summer maize cropping system mainly came from nitrogen fertilizer production(48.30% and nitrogen fertilizer application(12.04%, irrigation electricity consumption(12.94% and machinery oil consumption(11.20%. Optimizing the application of fertilizer, reducing the amount of nitrogen fertilizer and saving water irrigation were important ways to realize the clean production.

Increasing Carbon Loss from Snow-Scoured Alpine Tundra in the Colorado Rocky Mountains: An Indicator of Climate Change?

Science.gov (United States)

Knowles, J. F.; Blanken, P.; Williams, M. W.; Lawrence, C. R.

2015-12-01

We used the eddy covariance method to continuously measure the net ecosystem exchange of carbon dioxide for seven years from a snow-scoured alpine tundra meadow on Niwot Ridge in Colorado, USA that may be underlain by sporadic permafrost. On average, the alpine tundra was a net annual source of 232 g C m-2 to the atmosphere, and the source strength of this ecosystem increased over the length of the seven year period due to both reduced carbon uptake during the growing season and increased respiration throughout the winter. To constrain the contribution of permafrost degradation to observed carbon emissions, we also measured the radiocarbon content of actively cycling, occluded, and mineral soil carbon pools across a meso-scale soil moisture and (possible) permafrost gradient within this meadow, as well as the seasonal radiocarbon content of soil respiration. These data suggest that wintertime soil respiration is limited to patches of wet meadow tundra that may be associated with permafrost. Furthermore, soil respiration from one of these locations indicates preferential turnover of a relatively slow cycling carbon pool during the winter. Given that summer air temperatures and positive degree days have been increasing on Niwot Ridge since the middle of the 20th century, this research suggests that an alpine tundra permafrost-respiration feedback to climate change, similar to that observed in arctic tundra ecosystems, may be currently underway.

Assessing Effect of Manure and Chemical Fertilizer on Net Primary Production, Soil Respiration and Carbon Budget in Winter Wheat (Triticum aestivum L. Ecosystem under Mashhad Climatic Condition

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Y alizade

2018-02-01

Full Text Available Introduction The imbalance between anthropogenic emissions of CO2 and the sequestration of CO2 from the atmosphere by ecosystems has led to an increase in the average concentration of this greenhouse gas (GHG in the atmosphere. Enhancing carbon sequestration in soil is an important issue to reduce net flux of carbon dioxide to the atmosphere. Soil organic carbon content is obtained from the difference between carbon input resulting from plant biomass and carbon losses the soil through different ways including soil respiration. CO2 emission varies largely during the year and is considerably affected by management type. The goal of this investigation was to study the effects of application of manure and chemical fertilizer on CO2 flux and carbon balance in agricultural system. Materials and Methods In order to evaluate the carbon dynamics and effect of fertilizer and manure management on soil respiration and carbon budget for winter wheat, an experiment was conducted as a randomized complete block design with three replications in research field of Faculty of Agriculture of Ferdowsi University of Mashhad for two years of 2010-2011 and 2011-2012 . The experimental treatments were 150 and 250 kg chemical nitrogen (N1 and N2, manure (M, manure plus chemical nitrogen (F-M and control (C. CO2 emission was measured six times during growth season and to minimize daily temperature variation error, the measurement was performed between 8 to 11 am. Chambers length and diameter were 50 cm and 30 cm respectively and their edges were held down 3 cm in soil in time of sampling so that no plant live mass was present in the chamber. Carbon budgets were estimated for two years using an ecological technique. Results and Discussion The net primary production (NPP was significantly higher in the F2 and F-M treatments with 6467 and 6294kg ha-1 in the first year and 6260 and 6410 kg ha-1 in the second year, respectively. The highest shoot to root ratio was obtained in

Fertilizers nitrogen balance under maizl and winter rye in lysimentric experiments

International Nuclear Information System (INIS)

Ionova, O.N.

1979-01-01

The balance of the labelled 15 N nitrogen fertilizers in lysimentric experiment carried oUt in the turf-podsolic medium loamy soil has been studied. The results of two year experiment (1976-1977) have shown that depending on the doses and time of introduction the use of fertilizer nitrogen by maize varied from 51 to 58 % and by winter rye from 52 to 59 %. Consolidation in the organic substance of soil constituted 18-26 and 17-33 %, respectively. The losses of fertilizer nitrogen varied (14-29 % under maize and 9-23 % under winter rye). Nitrogen losses as a result of atmospheric precipitation infiltration both under maize and winter rye occured mainly at the expense of nitrogen of soil and reached considerable dimensions (31 kg) only under conditions of exceeding moistening of 1976. The losses of fertilizer nitrogen caused by washing out do not exceed 1 % for two years. The main losses of fertilizer nitrogen occurred in the form of gaseous nitrogen compounds

Electrochemical and weight-loss study of carbon steel corrosion

International Nuclear Information System (INIS)

Thomas, V.J.; Olive, R.P.

2007-01-01

The Point Lepreau Generating Station (PLGS) will undergo an 18 month refurbishment project beginning in April, 2008. During this time, most of the carbon steel piping in the primary loop will be drained of water and dried. However, some water will remain during the shutdown due to the lack of drains in some lower points in the piping system. As a result, it is necessary to examine the effect of corrosion during the refurbishment. This study examined the effect of several variables on the corrosion rate of clean carbon steel. Specifically, the effect of oxygen in the system and the presence of chloride ions were evaluated. Corrosion rates were determined using both a weight-loss technique and electrochemical methods. The experiment was conducted at room temperature. The corrosion products from the experiment were analyzed using a Raman microscope. The results of the weight-loss measurements show that the corrosion rate of polished carbon steel is independent of both the presence of oxygen and chloride ions. The electrochemical method failed to yield meaningful results due to the lack of clearly interpretable data and the inherent subjectivity in the analysis. Lepidocricite was found to be the main corrosion product using the Raman microscope. (author)

Tropical forests are a net carbon source based on aboveground measurements of gain and loss.

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Baccini, A; Walker, W; Carvalho, L; Farina, M; Sulla-Menashe, D; Houghton, R A

2017-10-13

The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year -1 ). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year -1 and gains of 436.5 ± 31.0 Tg C year -1 Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Connecting above and below: the impacts of large wildlife loss and pastoralism on savanna carbon dynamics

Science.gov (United States)

Forbes, E. S.; Young, H. S.; Young, T.; Schimel, J.

2016-12-01

There is widespread evidence that large wildlife species contribute to ecosystem carbon efflux; however, their influence is not incorporated into traditional carbon models. As large wildlife loss continues in the Anthropocene and in the face of climate change, it becomes increasingly important to understand the impacts of their loss on ecosystem carbon. The charismatic, threatened wildlife in central Kenya's savanna provide an ideal framework for these questions. We compared differences in carbon efflux in the presence or absence of native herbivores and/or cattle, as a proxy for wildlife loss and the interaction of pastoralism. We measured carbon dynamics in situ with a closed-chamber system and microbial respiration rates in lab by incubating sampled soil. We discovered a significant effect of herbivore presence/absence on carbon efflux: incubated soils collected from plots with cattle only exhibit greater carbon accumulation and faster initial respiration rates than soils collected from plots with native herbivores and no cattle, native herbivores and cattle, and neither native herbivores nor cattle. When measured in situ, plots with no herbivores show higher efflux than plots with only native herbivores, and plots with both. The data also suggest that grazing pressure results in successively lower efflux. The differences in these studies imply that the impacts of large wildlife loss differ on microbial respiration as an isolated mechanism in ecosystem carbon exchange, and total carbon efflux. This is most likely because in situ efflux measurements encompass environmental variables as well as soil microbial respiration. The lab data suggest that cattle as the only herbivore causes greater soil microbial efflux compared to native herbivores alone, native herbivores with cattle, or no herbivores. The in situ data show that no herbivores results in increased carbon efflux, and suggest that increasing numbers of herbivores lowers efflux.These studies demonstrate

High resolution spectroscopy of H+ energy loss in thin carbon film

International Nuclear Information System (INIS)

Matsunami, Noriaki; Kitoh, Kenshin

1991-05-01

The energy loss of ∼100 keV H + transmitted through thin carbon film of ∼7 nm has been measured with the resolution of ∼20 eV. We have observed new energy loss peaks around 210 and 400 eV in addition to the normal energy loss peak around 1 keV. We find that the experimental artifacts, ionization of C K-(290 eV) and impurity inner-shells, extreme non-uniformity of films, events associated with elastic scattering are not responsible for these peaks. The origin of these low energy loss peaks will be discussed. (author)

Winter Ground Temperatures Control Snowmelt DOC Export From a Discontinuous Permafrost Watershed: A Multi-Year Perspective

Science.gov (United States)

Carey, S. K.

2006-12-01

For discontinuous and continuous permafrost watersheds, the largest mass flux of dissolved organic carbon (DOC) occurs during the snowmelt period. During this time, available allochtonous organic carbon that has accumulated over the winter in frozen organic soils is rapidly flushed to the basin outlet. While this process has been observed now in many river systems of different size and location, there have been few inter-annual reports on the mass of DOC loss and the factors controlling its variability during freshet. Hydrological and DOC fluxes were recorded for the 2002, 2003 and 2006 snowmelt season with supplementary over-winter data for an 8 square kilometer sub-basin (Granger Basin) of the Wolf Creek Research Basin, Yukon Territory, Canada. Granger Basin is an alpine catchment above treeline underlain with discontinuous permafrost (approximately 70 %) and has widespread surface organic soils up to 0.4 m in thickness. Pre-melt snow water equivalent varied widely throughout the basin, yet was greatest in 2006, followed by 2002 and 2003. Ground temperatures were notably colder throughout the 2003 winter compared with 2006 and 2002. For all years, discharge began in mid-May, and was a continuous event in 2002 and 2006. In 2003 four distinct melt-periods were observed due to rising and falling temperatures. During freshet, stream DOC concentration increased rapidly from 15 mg C/L on the first ascending limb of the hydrograph in each year. In 2003, DOC was largely flushed from the catchment several weeks prior to peak freshet. DOC concentration in wells and piezometers followed a similar pattern to streamflow DOC, with 2003 groundwater DOC concentrations less than 2002 and 2006. The total mass flux of DOC during freshet was 0.85, 0.45 and 1.01 g C/m2 for 2002, 2003 and 2006 respectively. Despite differences in pre-melt snow accumulation, the timing of melt and the volume of discharge, it appears that spring DOC export is largely controlled by over-winter ground

Carbon gas exchange of a re-vegetated cut-away peatland five decades after abandonment

International Nuclear Information System (INIS)

Yli-Petaeys, M.; Laine, J.; Vasander, H.; Tuittila, E.-S.

2007-01-01

Only little is known about the long-term carbon dynamics related to peatland restoration. We studied CO 2 and CH 4 dynamics of spontaneously regenerated peat trenches five decades after peat harvesting had ceased. We used non-linear regression models and interpolation for simulating gas exchange of four regenerating plant communities during two growing seasons and one winter. The studied communities all acted as seasonal (June-September) sinks of CO 2 between 14 and 118 g C m -2 , while the emissions of CH 4 ranged from -4.9 to -28.8 g C m -2 . When the winter time losses of carbon and the estimated leaching were subtracted, the balance was very low or negative: between -67 and 31 g C m -2 . The low or even negative annual carbon balance in all communities may suggest a decrease in carbon sink strength in the advanced regeneration after the previously observed strong sink in the first regeneration stages caused by mass colonization by Eriophorum. (orig.)

Simulated soil organic carbon response to tillage, yield, and climate change in the southeastern Coastal Plains

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Intensive tillage, low-residue crops, and a warm, humid climate have contributed to soil organic carbon (SOC) loss in the southeastern Coastal Plains region. Conservation (CnT) tillage and winter cover cropping are current management practices to rebuild SOC; however, there is sparse long-term field...

Winter-to-winter variations in indoor radon

International Nuclear Information System (INIS)

Mose, D.G.; Mushrush, G.W.; Kline, S.W.

1989-01-01

Indoor radon concentrations in northern Virginia and central Maryland show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, compared to the winter of 1986-1987, the winter of 1987-1988 was warmer and drier. Consequently, winter-to-winter indoor radon decreased by about 25%. This winter-to-winter decrease is unexpectedly large, and simulates winter-to-summer variations that have been reported

Aboveground carbon loss in natural and managed tropical forests from 2000 to 2012

International Nuclear Information System (INIS)

Tyukavina, A; Hansen, M C; Potapov, P V; Krylov, A M; Turubanova, S; Baccini, A; Houghton, R A; Goetz, S J; Stehman, S V

2015-01-01

Tropical forests provide global climate regulation ecosystem services and their clearing is a significant source of anthropogenic greenhouse gas (GHG) emissions and resultant radiative forcing of climate change. However, consensus on pan-tropical forest carbon dynamics is lacking. We present a new estimate that employs recommended good practices to quantify gross tropical forest aboveground carbon (AGC) loss from 2000 to 2012 through the integration of Landsat-derived tree canopy cover, height, intactness and forest cover loss and GLAS-lidar derived forest biomass. An unbiased estimate of forest loss area is produced using a stratified random sample with strata derived from a wall-to-wall 30 m forest cover loss map. Our sample-based results separate the gross loss of forest AGC into losses from natural forests (0.59 PgC yr −1 ) and losses from managed forests (0.43 PgC yr −1 ) including plantations, agroforestry systems and subsistence agriculture. Latin America accounts for 43% of gross AGC loss and 54% of natural forest AGC loss, with Brazil experiencing the highest AGC loss for both categories at national scales. We estimate gross tropical forest AGC loss and natural forest loss to account for 11% and 6% of global year 2012 CO 2 emissions, respectively. Given recent trends, natural forests will likely constitute an increasingly smaller proportion of tropical forest GHG emissions and of global emissions as fossil fuel consumption increases, with implications for the valuation of co-benefits in tropical forest conservation. (letter)

Improving winter leaf area index estimation in evergreen coniferous forests and its significance in carbon and water fluxes modeling

Science.gov (United States)

Wang, R.; Chen, J. M.; Luo, X.

2016-12-01

Modeling of carbon and water fluxes at the continental and global scales requires remotely sensed LAI as inputs. For evergreen coniferous forests (ENF), severely underestimated winter LAI has been one of the issues for mostly available remote sensing products, which could cause negative bias in the modeling of Gross Primary Productivity (GPP) and evapotranspiration (ET). Unlike deciduous trees which shed all the leaves in winter, conifers retains part of their needles and the proportion of the retained needles depends on the needle longevity. In this work, the Boreal Ecosystem Productivity Simulator (BEPS) was used to model GPP and ET at eight FLUXNET Canada ENF sites. Two sets of LAI were used as the model inputs: the 250m 10-day University of Toronto (U of T) LAI product Version 2 and the corrected LAI based on the U of T LAI product and the needle longevity of the corresponding tree species at individual sites. Validating model daily GPP (gC/m2) against site measurements, the mean RMSE over eight sites decreases from 1.85 to 1.15, and the bias changes from -0.99 to -0.19. For daily ET (mm), mean RMSE decreases from 0.63 to 0.33, and the bias changes from -0.31 to -0.16. Most of the improvements occur in the beginning and at the end of the growing season when there is large correction of LAI and meanwhile temperature is still suitable for photosynthesis and transpiration. For the dormant season, the improvement in ET simulation mostly comes from the increased interception of precipitation brought by the elevated LAI during that time. The results indicate that model performance can be improved by the application the corrected LAI. Improving the winter RS LAI can make a large impact on land surface carbon and energy budget.

Winter-catastrophies in the reindeer husbandry of Finland: Losses and their prevention

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Timo Helle

1982-05-01

Full Text Available The paper deals with the occurreance of disastrous winters to the reindeer industry in Finland with special attention on the winter catastrophies and tje condition of the pastures, the influence of the disasters upon the population dynamic of the reindeer and the methods used to prevent catastrophies. A reindeer catastrophy has been defined as a situation where the number of reindeer stays 20% below the mean of the reindeer numbers during the two preceeding years. During the winter-catastrophies from 1970/71 to 1980/81 4.5% of the total reindeer number was lost. The highest losses were found in the northwesternmost part of Lappland, where there is no alternative to the reindeer lichen as it is in the middle and southern part of the reindeer industry area (arboreal lichens and supplemental feeding. In Kaldoaivi reindeer association (district, which has been studied in detail, the calf percentage is depending upon how the reindeer is able to manage the winter (r=0.62, n=ll, p«0.05. There is also a positive correlation between the slaughterweight of the calves in the early winter and the calf rate (r=0.79, n=7, p«0.05.During severe winters the mortality rate of males exceeds that of the females. Winter-catastrophies may be prevented by deminishing the numer of reindeer and by guiding the harvest to the most risky cohorts of the population. It has been proved that supplementary and emergency feeding are the most effective methods. In a normal year during the 1970s the total use of dry hay was 0.5—1.5 mill, kg., being up to 5.9—12.5 kg. per reindeer/year. In normal winters 10—16% of the total reindeer stock was intensively fed in enclosures. Supplementary feeding in enclosures is most common in the middle and southern parts of the reindeer industry area, where the essential feed is grown on own land.Katotalvet suomen poronhoidossa: menetykset ja Niiden Torjunta.Abstract in Finnish / Yhteenveto: Artikkeli käsittelee katastrofitalvien

Winter in the Ouachitas--a severe winter storm signature in Pinus echinata in the Ouachita Mountains of Oklahoma and Arkansas, USA

Science.gov (United States)

Douglas J. Stevenson; Thomas B. Lynch; Pradip Saud; Robert Heineman; Randal Holeman; Dennis Wilson; Keith Anderson; Chris Cerny; James M. Guldin

2016-01-01

Each year severe winter storms (≈ice storms) damage trees throughout the southern USA. Arkansas and Oklahoma have a history of severe winter storms. To extend that history back beyond the reach of written records, a distinctive tree ring pattern or signature is needed. Storm-caused breakage, branch loss and bending stress provide that signature. We found a severe storm...

Controls on winter ecosystem respiration in temperate and boreal ecosystems

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T. Wang

2011-07-01

Full Text Available Winter CO₂ fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal patterns of winter ecosystem respiration (R_eco of northern ecosystems are poorly understood. For this reason, we analyzed eddy covariance flux data from 57 ecosystem sites ranging from ~35° N to ~70° N. Deciduous forests were characterized by the highest winter R_eco rates (0.90 ± 0.39 g C m⁻² d⁻¹, when winter is defined as the period during which daily air temperature remains below 0 °C. By contrast, arctic wetlands had the lowest winter R_eco rates (0.02 ± 0.02 g C m⁻² d⁻¹. Mixed forests, evergreen needle-leaved forests, grasslands, croplands and boreal wetlands were characterized by intermediate winter R_eco rates (g C m⁻² d⁻¹ of 0.70(±0.33, 0.60(±0.38, 0.62(±0.43, 0.49(±0.22 and 0.27(±0.08, respectively. Our cross site analysis showed that winter air (T_air and soil (T_soil temperature played a dominating role in determining the spatial patterns of winter R_eco in both forest and managed ecosystems (grasslands and croplands. Besides temperature, the seasonal amplitude of the leaf area index (LAI, inferred from satellite observation, or growing season gross primary productivity, which we use here as a proxy for the amount of recent carbon available for R_eco in the subsequent winter, played a marginal role in winter CO₂ emissions from forest ecosystems. We found that winter R_eco sensitivity to temperature variation across space (

Comparison of snowpack and winter wet-deposition chemistry in the Rocky Mountains, USA: implications for winter dry deposition

Science.gov (United States)

Clow, David W.; Ingersoll, George P.; Mast, M. Alisa; Turk, John T.; Campbell, Donald H.

Depth-integrated snowpack chemistry was measured just prior to maximum snowpack depth during the winters of 1992-1999 at 12 sites co-located with National Atmospheric Deposition Program/National Trend Network (NADP/NTN) sites in the central and southern Rocky Mountains, USA. Winter volume-weighted mean wet-deposition concentrations were calculated for the NADP/NTN sites, and the data were compared to snowpack concentrations using the paired t-test and the Wilcoxon signed-rank test. No statistically significant differences were indicated in concentrations of SO 42- or NO 3- ( p>0.1). Small, but statistically significant differences ( p⩽0.03) were indicated for all other solutes analyzed. Differences were largest for Ca 2+ concentrations, which on average were 2.3 μeq l -1 (43%) higher in the snowpack than in winter NADP/NTN samples. Eolian carbonate dust appeared to influence snowpack chemistry through both wet and dry deposition, and the effect increased from north to south. Dry deposition of eolian carbonates was estimated to have neutralized an average of 6.9 μeq l -1 and a maximum of 12 μeq l -1 of snowpack acidity at the southernmost sites. The good agreement between snowpack and winter NADP/NTN SO 42- and NO 3- concentrations indicates that for those solutes the two data sets can be combined to increase data density in high-elevation areas, where few NADP/NTN sites exist. This combination of data sets will allow for better estimates of atmospheric deposition of SO 42- and NO 3- across the Rocky Mountain region.

Variable carbon losses from recurrent fires in drained tropical peatlands.

Science.gov (United States)

Konecny, Kristina; Ballhorn, Uwe; Navratil, Peter; Jubanski, Juilson; Page, Susan E; Tansey, Kevin; Hooijer, Aljosja; Vernimmen, Ronald; Siegert, Florian

2016-04-01

Tropical peatland fires play a significant role in the context of global warming through emissions of substantial amounts of greenhouse gases. However, the state of knowledge on carbon loss from these fires is still poorly developed with few studies reporting the associated mass of peat consumed. Furthermore, spatial and temporal variations in burn depth have not been previously quantified. This study presents the first spatially explicit investigation of fire-driven tropical peat loss and its variability. An extensive airborne Light Detection and Ranging data set was used to develop a prefire peat surface modelling methodology, enabling the spatially differentiated quantification of burned area depth over the entire burned area. We observe a strong interdependence between burned area depth, fire frequency and distance to drainage canals. For the first time, we show that relative burned area depth decreases over the first four fire events and is constant thereafter. Based on our results, we revise existing peat and carbon loss estimates for recurrent fires in drained tropical peatlands. We suggest values for the dry mass of peat fuel consumed that are 206 t ha(-1) for initial fires, reducing to 115 t ha(-1) for second, 69 t ha(-1) for third and 23 t ha(-1) for successive fires, which are 58-7% of the current IPCC Tier 1 default value for all fires. In our study area, this results in carbon losses of 114, 64, 38 and 13 t C ha(-1) for first to fourth fires, respectively. Furthermore, we show that with increasing proximity to drainage canals both burned area depth and the probability of recurrent fires increase and present equations explaining burned area depth as a function of distance to drainage canal. This improved knowledge enables a more accurate approach to emissions accounting and will support IPCC Tier 2 reporting of fire emissions. © 2015 John Wiley & Sons Ltd.

Winter Cover Crop Effects on Nitrate Leaching in Subsurface Drainage as Simulated by RZWQM-DSSAT

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Malone, R. W.; Chu, X.; Ma, L.; Li, L.; Kaspar, T.; Jaynes, D.; Saseendran, S. A.; Thorp, K.; Yu, Q.

2007-12-01

Planting winter cover crops such as winter rye (Secale cereale L.) after corn and soybean harvest is one of the more promising practices to reduce nitrate loss to streams from tile drainage systems without negatively affecting production. Because availability of replicated tile-drained field data is limited and because use of cover crops to reduce nitrate loss has only been tested over a few years with limited environmental and management conditions, estimating the impacts of cover crops under the range of expected conditions is difficult. If properly tested against observed data, models can objectively estimate the relative effects of different weather conditions and agronomic practices (e.g., various N fertilizer application rates in conjunction with winter cover crops). In this study, an optimized winter wheat cover crop growth component was integrated into the calibrated RZWQM-DSSAT hybrid model and then we compare the observed and simulated effects of a winter cover crop on nitrate leaching losses in subsurface drainage water for a corn-soybean rotation with N fertilizer application rates over 225 kg N ha-1 in corn years. Annual observed and simulated flow-weighted average nitrate concentration (FWANC) in drainage from 2002 to 2005 for the cover crop treatments (CC) were 8.7 and 9.3 mg L-1 compared to 21.3 and 18.2 mg L-1 for no cover crop (CON). The resulting observed and simulated FWANC reductions due to CC were 59% and 49%. Simulations with the optimized model at various N fertilizer rates resulted in average annual drainage N loss differences between CC and CON to increase exponentially from 12 to 34 kg N ha-1 for rates of 11 to 261 kg N ha-1. The results suggest that RZWQM-DSSAT is a promising tool to estimate the relative effects of a winter crop under different conditions on nitrate loss in tile drains and that a winter cover crop can effectively reduce nitrate losses over a range of N fertilizer levels.

Electrolyte loss mechanism of molten carbonate fuel cells. 1; Yoyu tansan`engata nenryo denchi ni okeru denkaishitsu loss kiko ni tsuite. 1

Energy Technology Data Exchange (ETDEWEB)

Sonai, A; Murata, K [Toshiba Research and Development Center, Kawasaki (Japan)

1993-11-01

During a single-cell disassembly test of molten carbonate fuel cells having been operated for 90 hours to 5500 hours, correlativity was discovered between decrease in the retained amount of electrolyte due to decrease in pore capacity of electrodes and electrolyte plates and the electrolyte loss. The electrolyte loss amount cannot be explained with the conventional mechanisms, thereby a new model was proposed. The cathode has shown very little change in the capacity change in pores with diameters smaller than 2 {mu}m per unit area. The anode has remained almost constant after 1000 hours, but the electrolyte plates have shown remarkable decrease. Therefore, it is possible to estimate that the electrolyte plates should have been the major cause for the electrolyte loss. The result of measuring the electrolyte loss amount agreed well with that estimated using pore capacity curves. This fact suggests that the electrolyte loss can be explained by a new mechanism that hypothesizes the existence of a largest size of retaining pores that can support carbonates and defines that the electrolyte loss is generated from decrease in the pore capacity. 7 refs., 8 figs., 1 tab.

Influence of pore structure on carbon retention/loss in soil macro-aggregates

Science.gov (United States)

Quigley, Michelle; Kravchenko, Alexandra; Rivers, Mark

2017-04-01

carbon protect were disparate. In intact-structure aggregates, prior to incubation, there was no association between carbon distribution and pores. After incubation, significant correlations (α=0.05) were observed between abundance of 6-40 μm pores and both soil organic carbon (SOC) and δ13C. Sections containing more 6-40 μm pores also had increased amounts of SOC (r2=0.23) with higher presence of C4 carbon (r2=0.27). This indicates preferential preservation of older carbon in the pores of this size range. Prior to incubation, destroyed-structure aggregates had higher amounts of C3 carbon associated with 40-95 μm pores (r2=0.14), pointing to a greater presence of newly added carbon within these pores. However, after incubation there was a significant loss of SOC from these pores (r2=0.22) and, specifically, the loss of C3 carbon (r2=0.16). In the studied soil, pores of 6-40 μm size range appeared to control the preservation of older carbon, while 40-95 μm pores controlled the fate of newly added carbon. Older carbon preservation in 6-40 μm pores was mostly observed in macro-aggregates from the soil with intact structure, while the associations between 40-95 μm pores and gains and losses of newly added carbon were primarily observed in the macro-aggregates that were formed anew in the sieved soil during the plant growing experiment.

Effects of road decommissioning on carbon stocks, losses, and emissions in north coastal California

Science.gov (United States)

Madej, Mary Ann; Seney, Joseph; van Mantgem, Philip

2013-01-01

During the last 3 decades, many road removal projects have been implemented on public and private lands in the United States to reduce erosion and other impacts from abandoned or unmaintained forest roads. Although effective in decreasing sediment production from roads, such activities have a carbon (C) cost as well as representing a carbon savings for an ecosystem. We assessed the carbon budget implications of 30 years of road decommissioning in Redwood National Park in north coastal California. Road restoration techniques, which evolved during the program, were associated with various carbon costs and savings. Treatment of 425 km of logging roads from 1979 to 2009 saved 72,000 megagrams (Mg) C through on-site soil erosion prevention, revegetation, and soil development on formerly compacted roads. Carbon sequestration will increase in time as forests and soils develop more fully on the restored sites. The carbon cost for this road decommissioning work, based on heavy equipment and vehicle fuel emissions, short-term soil loss, and clearing of vegetation, was 23,000 Mg C, resulting in a net carbon savings of 49,000 Mg C to date. Nevertheless, the degree to which soil loss is a carbon sink or source in steep mountainous watersheds needs to be further examined. The ratio of carbon costs to savings will differ by ecosystem and road removal methodology, but the procedure outlined here to assess carbon budgets on restoration sites should be transferable to other systems.

Satellite passive microwaves for monitoring deforestation and drought-induced carbon losses in sub-Saharan Africa

Science.gov (United States)

Brandt, M.; Wigneron, J. P.; Chave, J.; Tagesson, T.; Penuelas, J.; Ciais, P.; Rasmussen, K.; Tian, F.; Mbow, C.; Al-Yaari, A.; Rodriguez-Fernandez, N.; Zhang, W.; Kerr, Y. H.; Tucker, C. J.; Mialon, A.; Verger, A.; Fensholt, R.

2017-12-01

The African continent is facing one of the driest periods in the past three decades and continuing deforestation. These disturbances threaten vegetation carbon (C) stocks and highlight the need for an operational tool for monitoring carbon stock dynamics. Knowledge of the amount, distribution, and turnover of carbon in African vegetation is crucial for understanding the effects of human pressure and climate change, but the shortcomings of optical and radar satellite products and the lack of systematic field inventories have led to considerable uncertainty in documenting patterns and dynamics of carbon stocks, in particular for drylands. Static carbon maps have been developed, but the temporal dynamics of carbon stocks cannot be derived from the benchmark maps, impeding timely, repeated, and reliable carbon assessments. The Soil Moisture and Ocean Salinity (SMOS) mission launched in 2009 was the first passive microwave-based satellite system operating at L-band (1.4 GHz) frequency. The low frequencies allow the satellite to sense deep within the canopy layer with less influence by the green non-woody plant components. The vegetation optical depth (VOD) derived from SMOS, henceforth L-VOD, is thus less sensitive to saturation effects, marking an important step forward in the monitoring of carbon as a natural resource. In this study, we apply for the first time L-VOD to quantify the inter-annual dynamics of aboveground carbon stocks for the period 2010-2016. We use this new technique to document patterns of carbon gains and losses in sub-Saharan Africa with a focus of dryland response to recent dry years. Results show that drylands lost carbon at a rate of -0.06 Pg C y-1 associated with drying trends, while humid areas lost only -0.02 Pg C y-1. These trends reflect a high inter-annual variability with a very wet (2011) and a very dry year (2016) associated with carbon gains and losses respectively. This study demonstrates, first, the operational applicability of L

Long-term Carbon Loss and Recovery Following Selective Logging in Amazon Forests

Energy Technology Data Exchange (ETDEWEB)

Huang, Maoyi; Asner, Gregory P.

2010-09-30

Amazon deforestation contributes significantly to global carbon (C) emissions. In comparison, the contribution from selective logging to atmospheric CO2 emissions, and its impact on regional C dynamics, is highly uncertain. Using a new geographically-based modeling approach in combination with high resolution remote sensing data from 1999-2002, we estimate that C emissions were 0.04 – 0.05 Pg C yr-1 due to selective logging from a ~2,664,960 km2 region of the Brazilian Amazon. Selective logging was responsible for 15-19% higher carbon emissions than reported from deforestation (clear-cutting) alone. Our simulations indicated that forest carbon lost via selective logging lasts two to three decades following harvest, and that the original live biomass takes up to a century to recover, if the forests are not subsequently cleared. The two- to three-decade loss of carbon results from the biomass damaged by logging activities, including leaves, wood, and roots, estimated to be 89.1 Tg C yr-1 from 1999-2002 over the study region, leaving 70.0 Tg C yr-1 and 7.9 Tg C yr-1 to accumulate as coarse woody debris and soil C, respectively. While avoided deforestation is central to crediting rainforest nations for reduced carbon emissions, the extent and intensity of selective logging are also critical to determining carbon emissions in the context of Reduced Emissions from Deforestation and Forest Degradation (REDD). We show that a combination of automated high-resolution satellite monitoring and detailed forest C modeling can yield spatially explicit estimates of harvest related C losses and subsequent recovery in support of REDD and other international carbon market mechanisms.

Effects of combustion emissions from the Eurasian continent in winter on seasonal δ 13C of elemental carbon in aerosols in Japan

Science.gov (United States)

Kawashima, Hiroto; Haneishi, Yuya

2012-01-01

We investigated suspended particulate matter (SPM, particles with a 100% cut-off aerodynamic diameter of 10 μm) and PM2.5 (particles with a 50% cut-off aerodynamic diameter of 2.5 μm) concentrations in aerosols sampled in Akita Prefecture, Japan, from April 2008 to January 2010, and the carbon isotope ratios (δ 13C) of elemental carbon (EC) in both SPM and PM2.5 and in samples from possible sources. We also determined the ion contents of SPM and estimated the back trajectories of air masses arriving at Akita Prefecture during the study period. The SPM concentration was very low (annual average, 15.2 μg m -3), and it tended to be higher in spring and lower in winter. We attributed the higher SPM in spring to dust storms brought from the Asian continent. The average annual PM2.5 concentration was 8.6 μg m -3. δ 13C of source samples (gasoline and diesel vehicle exhaust, fireplace soot, open biomass burning emissions, street dust, soil, charcoal, and coal) ranged from -34.7‰ to -1.8‰. δ 13C values of soot from gasoline light-duty (-24.4 ± 0.7‰) and passenger vehicles (-24.1 ± 0.6‰) were very similar to that of soot from all diesel vehicles (-24.3 ± 0.3‰). δ 13C was enriched in SPM in winter compared with summer values, moreover, only a slight seasonal trend was detected in δ 13C in PM2.5. From these data and the source results, we hypothesized that the enrichment of δ 13C of SPM and PM2.5 in winter was a long-range effect of overseas combustion processes such as coal combustion. In addition, δ 13C of SPM was correlated with Cl - and Mg 2+ contents in SPM, suggesting the influence of sea salt. We verified this hypothesis by back trajectory analyses. The results indicated a continental influence effects on EC of SPM and PM2.5 in winter.

Energy-loss of He ions in carbon allotropes studied by elastic resonance in backscattering spectra

Energy Technology Data Exchange (ETDEWEB)

Tosaki, Mitsuo, E-mail: tosaki.mitsuo.3v@kyoto-u.ac.jp [Radioisotope Research Center, Kyoto University, Kyoto 606-8501 (Japan); Rauhala, Eero [Department of Physics, University of Helsinki (Finland)

2015-10-01

Backscattering spectra for {sup 4}He ions incident on carbon allotropes have been measured in the energy range from 4.30 to 4.95 MeV in steps of 50–100 keV at scattering angles of 106° and 170°. We used three carbon allotropes: graphite, diamond and amorphous carbon. For all these allotropes, we can observe the sharp ({sup 4}He, {sup 12}C) elastic nuclear resonance at the He ion energy of 4.265 MeV in the backscattering spectra. By varying the incident He energy, we have systematically analyzed the profiles of the resonance peaks to study the energy-loss processes: stopping cross-sections and energy-loss straggling around the interesting region of the stopping maximum at about 500 keV. We focus on the resonance profiles and investigate an allotropic effect concerning the energy-loss. Furthermore, an energy bunching effect on the straggling is presented and the mechanism is discussed.

Winter carbon dioxide effluxes from Arctic ecosystems: An overview and comparison of methodologies

DEFF Research Database (Denmark)

Björkman, M.P.; Morgner, E.; Cooper, E.J.

2010-01-01

removal, (3) diffusion measurements, F2-point, within the snowpack, and (4) a trace gas technique, FSF6, with multiple gas sampling within the snowpack. According to measurements collected from shallow and deep snow cover in High Arctic Svalbard and subarctic Sweden during the winter of 2007......The winter CO2 efflux from subnivean environments is an important component of annual C budgets in Arctic ecosystems and consequently makes prediction and estimations of winter processes as well as incorporations of these processes into existing models important. Several methods have been used......, Fsoil is assumed to measure soil production, whereas FSF6, Fsnow, and F2-point are considered better approaches for quantifying exchange processes between the soil, snow, and the atmosphere. This study indicates that estimates of winter CO2 emissions may vary more as a result of the method used than...

Deforestation and Carbon Loss in Southwest Amazonia: Impact of Brazil's Revised Forest Code

Science.gov (United States)

Roriz, Pedro Augusto Costa; Yanai, Aurora Miho; Fearnside, Philip Martin

2017-09-01

In 2012 Brazil's National Congress altered the country's Forest Code, decreasing various environmental protections in the set of regulations governing forests. This suggests consequences in increased deforestation and emissions of greenhouse gases and in decreased protection of fragile ecosystems. To ascertain the effects, a simulation was run to the year 2025 for the municipality (county) of Boca do Acre, Amazonas state, Brazil. A baseline scenario considered historical behavior (which did not respect the Forest Code), while two scenarios considered full compliance with the old Forest Code (Law 4771/1965) and the current Code (Law 12,651/2012) regarding the protection of "areas of permanent preservation" (APPs) along the edges of watercourses. The models were parameterized from satellite imagery and simulated using Dinamica-EGO software. Deforestation actors and processes in the municipality were observed in loco in 2012. Carbon emissions and loss of forest by 2025 were computed in the three simulation scenarios. There was a 10% difference in the loss of carbon stock and of forest between the scenarios with the two versions of the Forest Code. The baseline scenario showed the highest loss of carbon stocks and the highest increase in annual emissions. The greatest damage was caused by not protecting wetlands and riparian zones.

Deforestation and Carbon Loss in Southwest Amazonia: Impact of Brazil's Revised Forest Code.

Science.gov (United States)

Roriz, Pedro Augusto Costa; Yanai, Aurora Miho; Fearnside, Philip Martin

2017-09-01

In 2012 Brazil's National Congress altered the country's Forest Code, decreasing various environmental protections in the set of regulations governing forests. This suggests consequences in increased deforestation and emissions of greenhouse gases and in decreased protection of fragile ecosystems. To ascertain the effects, a simulation was run to the year 2025 for the municipality (county) of Boca do Acre, Amazonas state, Brazil. A baseline scenario considered historical behavior (which did not respect the Forest Code), while two scenarios considered full compliance with the old Forest Code (Law 4771/1965) and the current Code (Law 12,651/2012) regarding the protection of "areas of permanent preservation" (APPs) along the edges of watercourses. The models were parameterized from satellite imagery and simulated using Dinamica-EGO software. Deforestation actors and processes in the municipality were observed in loco in 2012. Carbon emissions and loss of forest by 2025 were computed in the three simulation scenarios. There was a 10% difference in the loss of carbon stock and of forest between the scenarios with the two versions of the Forest Code. The baseline scenario showed the highest loss of carbon stocks and the highest increase in annual emissions. The greatest damage was caused by not protecting wetlands and riparian zones.

National-scale estimation of gross forest aboveground carbon loss: a case study of the Democratic Republic of the Congo

International Nuclear Information System (INIS)

Tyukavina, A; Potapov, P V; Turubanova, S A; Hansen, M C; Stehman, S V; Baccini, A; Goetz, S J; Laporte, N T; Houghton, R A

2013-01-01

Recent advances in remote sensing enable the mapping and monitoring of carbon stocks without relying on extensive in situ measurements. The Democratic Republic of the Congo (DRC) is among the countries where national forest inventories (NFI) are either non-existent or out of date. Here we demonstrate a method for estimating national-scale gross forest aboveground carbon (AGC) loss and associated uncertainties using remotely sensed-derived forest cover loss and biomass carbon density data. Lidar data were used as a surrogate for NFI plot measurements to estimate carbon stocks and AGC loss based on forest type and activity data derived using time-series multispectral imagery. Specifically, DRC forest type and loss from the FACET (Forêts d’Afrique Centrale Evaluées par Télédétection) product, created using Landsat data, were related to carbon data derived from the Geoscience Laser Altimeter System (GLAS). Validation data for FACET forest area loss were created at a 30-m spatial resolution and compared to the 60-m spatial resolution FACET map. We produced two gross AGC loss estimates for the DRC for the last decade (2000–2010): a map-scale estimate (53.3 ± 9.8 Tg C yr −1 ) accounting for whole-pixel classification errors in the 60-m resolution FACET forest cover change product, and a sub-grid estimate (72.1 ± 12.7 Tg C yr −1 ) that took into account 60-m cells that experienced partial forest loss. Our sub-grid forest cover and AGC loss estimates, which included smaller-scale forest disturbances, exceed published assessments. Results raise the issue of scale in forest cover change mapping and validation, and subsequent impacts on remotely sensed carbon stock change estimation, particularly for smallholder dominated systems such as the DRC. (letter)

Vascular plants promote ancient peatland carbon loss with climate warming.

Science.gov (United States)

Walker, Tom N; Garnett, Mark H; Ward, Susan E; Oakley, Simon; Bardgett, Richard D; Ostle, Nicholas J

2016-05-01

Northern peatlands have accumulated one third of the Earth's soil carbon stock since the last Ice Age. Rapid warming across northern biomes threatens to accelerate rates of peatland ecosystem respiration. Despite compensatory increases in net primary production, greater ecosystem respiration could signal the release of ancient, century- to millennia-old carbon from the peatland organic matter stock. Warming has already been shown to promote ancient peatland carbon release, but, despite the key role of vegetation in carbon dynamics, little is known about how plants influence the source of peatland ecosystem respiration. Here, we address this issue using in situ (14)C measurements of ecosystem respiration on an established peatland warming and vegetation manipulation experiment. Results show that warming of approximately 1 °C promotes respiration of ancient peatland carbon (up to 2100 years old) when dwarf-shrubs or graminoids are present, an effect not observed when only bryophytes are present. We demonstrate that warming likely promotes ancient peatland carbon release via its control over organic inputs from vascular plants. Our findings suggest that dwarf-shrubs and graminoids prime microbial decomposition of previously 'locked-up' organic matter from potentially deep in the peat profile, facilitating liberation of ancient carbon as CO2. Furthermore, such plant-induced peat respiration could contribute up to 40% of ecosystem CO2 emissions. If consistent across other subarctic and arctic ecosystems, this represents a considerable fraction of ecosystem respiration that is currently not acknowledged by global carbon cycle models. Ultimately, greater contribution of ancient carbon to ecosystem respiration may signal the loss of a previously stable peatland carbon pool, creating potential feedbacks to future climate change. © 2016 John Wiley & Sons Ltd.

Fuel treatment impacts on estimated wildfire carbon loss from forests in Montana, Oregon, California, and Arizona

Science.gov (United States)

Stephens, Scott L.; Boerner, Ralph E.J.; Maghaddas, Jason J.; Maghaddas, Emily E.Y.; Collins, Brandon M.; Dow, Christopher B.; Edminster, Carl; Fiedler, Carl E.; Fry, Danny L.; Hartsough, Bruce R.; Keeley, Jon E.; Knapp, Eric E.; McIver, James D.; Skinner, Carl N.; Youngblood, Andrew P.

2012-01-01

Using forests to sequester carbon in response to anthropogenically induced climate change is being considered across the globe. A recent U.S. executive order mandated that all federal agencies account for sequestration and emissions of greenhouse gases, highlighting the importance of understanding how forest carbon stocks are influenced by wildfire. This paper reports the effects of the most common forest fuel reduction treatments on carbon pools composed of live and dead biomass as well as potential wildfire emissions from six different sites in four western U.S. states. Additionally, we predict the median forest product life spans and uses of materials removed during mechanical treatments. Carbon loss from modeled wildfire-induced tree mortality was lowest in the mechanical plus prescribed fire treatments, followed by the prescribed fire-only treatments. Wildfire emissions varied from 10–80 Mg/ha and were lowest in the prescribed fire and mechanical followed by prescribed fire treatments at most sites. Mean biomass removals per site ranged from approximately 30–60 dry Mg/ha; the median lives of products in first use varied considerably (from 50 years). Our research suggests most of the benefits of increased fire resistance can be achieved with relatively small reductions in current carbon stocks. Retaining or growing larger trees also reduced the vulnerability of carbon loss from wildfire. In addition, modeled vulnerabilities to carbon losses and median forest product life spans varied considerably across our study sites, which could be used to help prioritize treatment implementation.

Winter Survival of Individual Honey Bees and Honey Bee Colonies Depends on Level of Varroa destructor Infestation

Science.gov (United States)

van Dooremalen, Coby; Gerritsen, Lonne; Cornelissen, Bram; van der Steen, Jozef J. M.; van Langevelde, Frank; Blacquière, Tjeerd

2012-01-01

Background Recent elevated winter loss of honey bee colonies is a major concern. The presence of the mite Varroa destructor in colonies places an important pressure on bee health. V. destructor shortens the lifespan of individual bees, while long lifespan during winter is a primary requirement to survive until the next spring. We investigated in two subsequent years the effects of different levels of V. destructor infestation during the transition from short-lived summer bees to long-lived winter bees on the lifespan of individual bees and the survival of bee colonies during winter. Colonies treated earlier in the season to reduce V. destructor infestation during the development of winter bees were expected to have longer bee lifespan and higher colony survival after winter. Methodology/Principal Findings Mite infestation was reduced using acaricide treatments during different months (July, August, September, or not treated). We found that the number of capped brood cells decreased drastically between August and November, while at the same time, the lifespan of the bees (marked cohorts) increased indicating the transition to winter bees. Low V. destructor infestation levels before and during the transition to winter bees resulted in an increase in lifespan of bees and higher colony survival compared to colonies that were not treated and that had higher infestation levels. A variety of stress-related factors could have contributed to the variation in longevity and winter survival that we found between years. Conclusions/Significance This study contributes to theory about the multiple causes for the recent elevated colony losses in honey bees. Our study shows the correlation between long lifespan of winter bees and colony loss in spring. Moreover, we show that colonies treated earlier in the season had reduced V. destructor infestation during the development of winter bees resulting in longer bee lifespan and higher colony survival after winter. PMID:22558421

Photochemically induced carbon dioxide production as a mechanism for carbon loss from plant litter in arid ecosystems

Science.gov (United States)

Brandt, L. A.; Bohnet, C.; King, J. Y.

2009-06-01

We investigated the potential for abiotic mineralization to carbon dioxide (CO2) via photodegradation to account for carbon (C) loss from plant litter under conditions typical of arid ecosystems. We exposed five species of grass and oak litter collected from arid and mesic sites to a factorial design of ultraviolet (UV) radiation (UV pass, UV block), and sterilization under dry conditions in the laboratory. UV pass treatments produced 10 times the amount of CO2 produced in UV block treatments. CO2 production rates were unaffected by litter chemistry or sterilization. We also exposed litter to natural solar radiation outdoors on clear, sunny days close to the summer solstice at midlatitudes and found that UV radiation (280-400 nm) accounted for 55% of photochemically induced CO2 production, while shortwave visible radiation (400-500 nm) accounted for 45% of CO2 production. Rates of photochemically induced CO2 production on a per-unit-mass basis decreased with litter density, indicating that rates depend on litter surface area. We found no evidence for leaching, methane production, or facilitation of microbial decomposition as alternative mechanisms for significant photochemically induced C loss from litter. We conclude that abiotic mineralization to CO2 is the primary mechanism by which C is lost from litter during photodegradation. We estimate that CO2 production via photodegradation could be between 1 and 4 g C m-2 a-1 in arid ecosystems in the southwestern United States. Taken together with low levels of litter production in arid systems, photochemical mineralization to CO2 could account for a significant proportion of annual carbon loss from litter in arid ecosystems.

Dynamic replacement and loss of soil carbon on eroding cropland

Science.gov (United States)

Harden, J.W.; Sharpe, J.M.; Parton, W.J.; Ojima, D.S.; Fries, T.L.; Huntington, T.G.; Dabney, S.M.

1999-01-01

Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, 14C, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet 14C models for different erosion and tillage histories. For this site, where 100 years of intensive cotton cropping were followed by fertilization and contour plowing, there was an initial and dramatic decline in soil carbon content from 1870 to 1950, followed by a dramatic increase in soil carbon. Soil erosion amplifies C loss and recovery: About 100% of the original, prehistoric soil carbon was likely lost over 127 years of intensive land use, but about 30% of that carbon was replaced after 1950. The eroded cropland was therefore a local sink for CO2 since the 1950s. However, a net CO2 sink requires a full accounting of eroded carbon, which in turn requires that decomposition rates in lower slopes or wetlands be reduced to about 20% of the upland value. As a result, erosion may induce unaccounted sinks or sources of CO2, depending on the fate of eroded carbon and its protection from decomposition. For erosion rates typical of the United States, the sink terms may be large enough (1 Gt yr-1, back-of-the-envelope) to warrant a careful accounting of site management, cropping, and fertilization histories, as well as burial rates, for a more meaningful global assessment.

Large contribution of fossil fuel derived secondary organic carbon to water soluble organic aerosols in winter haze in China

Science.gov (United States)

Zhang, Yan-Lin; El-Haddad, Imad; Huang, Ru-Jin; Ho, Kin-Fai; Cao, Jun-Ji; Han, Yongming; Zotter, Peter; Bozzetti, Carlo; Daellenbach, Kaspar R.; Slowik, Jay G.; Salazar, Gary; Prévôt, André S. H.; Szidat, Sönke

2018-03-01

Water-soluble organic carbon (WSOC) is a large fraction of organic aerosols (OA) globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (14C) and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32-47 % of WSOC. Secondary organic carbon (SOC) dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 %) and Xi'an (26 ± 9 %). The most important primary sources were biomass burning emissions, contributing 17-26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban and background regions in Asia, Europe and the USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 %) to WSOC aerosols in the Northern Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the eastern Asian pollution outflow, especially during winter, due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

Science.gov (United States)

Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

2016-04-01

balance for whole years showed that carbon losses were observed for all studied agroecosystems. It was minimal for field with winter wheat, with mustard, used as green manure, and it was maximal for field with vetch and oat mix. Values about 200-250 g C m-2 per year may be considered as estimated values for the total carbon loss for agroecosystems with grain crops and grass mixt on sod-podzolic soils. The use of mustard as a green manure may reduce this value by three-quarters.

Climate change in winter versus the growing-season leads to different effects on soil microbial activity in northern hardwood forests

Science.gov (United States)

Sorensen, P. O.; Templer, P. H.; Finzi, A.

2014-12-01

Mean winter air temperatures have risen by approximately 2.5˚ C per decade over the last fifty years in the northeastern U.S., reducing the maximum depth of winter snowpack by approximately 26 cm over this period and the duration of winter snow cover by 3.6 to 4.2 days per decade. Forest soils in this region are projected to experience a greater number of freeze-thaw cycles and lower minimum winter soil temperatures as the depth and duration of winter snow cover declines in the next century. Climate change is likely to result not only in lower soil temperatures during winter, but also higher soil temperatures during the growing-season. We conducted two complementary experiments to determine how colder soils in winter and warmer soils in the growing-season affect microbial activity in hardwood forests at Harvard Forest, MA and Hubbard Brook Experimental Forest, NH. A combination of removing snow via shoveling and buried heating cables were used to induce freeze-thaw events during winter and to warm soils 5˚C above ambient temperatures during the growing-season. Increasing the depth and duration of soil frost via snow-removal resulted in short-term reductions in soil nitrogen (N) production via microbial proteolytic enzyme activity and net N mineralization following snowmelt, prior to tree leaf-out. Declining mass specific rates of carbon (C) and N mineralization associated with five years of snow removal at Hubbard Brook Experimental Forest may be an indication of microbial physiological adaptation to winter climate change. Freeze-thaw cycles during winter reduced microbial extracellular enzyme activity and the temperature sensitivity of microbial C and N mineralization during the growing-season, potentially offsetting nutrient and soil C losses due to soil warming in the growing-season. Our multiple experimental approaches show that winter climate change is likely to contribute to reduced microbial activity in northern hardwood forests.

The importance of agricultural lands for Himalayan birds in winter.

Science.gov (United States)

Elsen, Paul R; Kalyanaraman, Ramnarayan; Ramesh, Krishnamurthy; Wilcove, David S

2017-04-01

The impacts of land-use change on biodiversity in the Himalayas are poorly known, notwithstanding widespread deforestation and agricultural intensification in this highly biodiverse region. Although intact primary forests harbor many Himalayan birds during breeding, a large number of bird species use agricultural lands during winter. We assessed how Himalayan bird species richness, abundance, and composition during winter are affected by forest loss stemming from agriculture and grazing. Bird surveys along 12 elevational transects within primary forest, low-intensity agriculture, mixed subsistence agriculture, and intensively grazed pastures in winter revealed that bird species richness and abundance were greatest in low-intensity and mixed agriculture, intermediate in grazed pastures, and lowest in primary forest at both local and landscape scales; over twice as many species and individuals were recorded in low-intensity agriculture than in primary forest. Bird communities in primary forests were distinct from those in all other land-use classes, but only 4 species were unique to primary forests. Low-, medium-, and high-intensity agriculture harbored 32 unique species. Of the species observed in primary forest, 80% had equal or greater abundance in low-intensity agricultural lands, underscoring the value of these lands in retaining diverse community assemblages at high densities in winter. Among disturbed landscapes, bird species richness and abundance declined as land-use intensity increased, especially in high-intensity pastures. Our results suggest that agricultural landscapes are important for most Himalayan bird species in winter. But agricultural intensification-especially increased grazing-will likely result in biodiversity losses. Given that forest reserves alone may inadequately conserve Himalayan birds in winter, comprehensive conservation strategies in the region must go beyond protecting intact primary forests and ensure that low-intensity agricultural

URCA neutrino-loss rates under conditions found in the carbon-oxygen cores of intermediate-mass stars

International Nuclear Information System (INIS)

Iben, I. Jr.

1978-01-01

In the hope of uncovering additional Urca-active nuclei that might appear during carbon burning in the electron-degenerate carbon-oxygen core of an asymptotic-branch star and avert a thermonuclear runaway, a nuclear-reaction matrix connecting 244 nuclear species has been constructed. Analytic expressions for rates of all relevant β-transitions are also presented and used. It is shown that in matter which is composed initially of elements in a solar-system distribution and which has undergone first complete hydrogen burning and then complete helium burning, neutrino-loss rates due to 11 Urca pairs either rival or exceed neutrino losses predicted by the charge- and neutral-current theories of weak interactions. Most remarkably, no new Urca pairs of any consequence appear as a result of several thousand reactions that are allowed to occur during carbon burning. The dominant Urca-loss rates are still due to the pairs 21 F- 21 Ne, 23 Ne- 23 Na, 25 Na- 25 Mg, and 25 Ne- 25 Na, as in matter containing a solar-system distribution of elements that has undergone prior processing during hydrogen- and helium-burning phases. The abundances of these Urca-active pairs are enhanced by one to three orders of magnitude as a consequence of carbon-burning reactions

Fluvial organic carbon losses from oil palm plantations on tropical peat, Sarawak, Southeast Asia

Science.gov (United States)

Cook, Sarah; Page, Susan; Evans, Chris; Whelan, Mick; Gauci, Vincent; Lip Khoon, Kho

2017-04-01

Tropical peatlands are valuable stores of carbon. However, tropical peat swamp forests (TPSFs) in Southeast Asia have increasingly been converted to other land-uses. For example, more than 25% of TPSFs are now under oil palm plantations. This conversion - requiring felling and burning of trees and drainage of the peat - can enhance carbon mineralization, dissolved organic carbon (DOC) losses and can contribute significantly to global anthropogenic greenhouse gas emissions, changing these natural carbon sinks into carbon sources. At present, relatively few scientifically sound studies provide dependable estimates of gaseous and fluvial carbon losses from oil palm plantations or from drained tropical peat in general. Here we present an annual (54 week) estimate of the export of dissolved and particulate organic carbon in water draining two oil palm estates and nearby stands of TPSF in Sarawak, Malaysia, subjected to varying degrees of past anthropogenic disturbance. Spectrophotometric techniques including SUVA254 (Specific Ultra-Violet Absorption) were used to gain insight into the aromaticity and subsequent bioavailability of the exported DOC. Water draining plantation and deforested land had a higher proportion of labile carbon compared to water draining forested areas. Preliminary data suggest a total fluvial DOC flux from plantations of ca. 190 g C m-2 year-1; nearly three times estimates from intact TPSFs (63 g C m-2 year-1). DOC accounted for between 86 % - 94 % of the total organic carbon lost (most of which was bioavailable). Wit et al. (2015) estimates that an average of 53 % of peat-derived DOC is decomposed and emitted as CO2, on a monthly basis. Based on these estimates our data suggests an additional 101 g CO2 m-2 may be emitted indirectly from fluvial organic carbon in degraded TPSFs per year. Overall, these findings emphasize the importance of including fluvial organic carbon fluxes when quantifying the impact of anthropogenic disturbance on the

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

Science.gov (United States)

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Padolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Mahoney, Michael J.; Richard, Erik

2002-01-01

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE III-Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999/2000 winter season. Aircraft-based water vapor, carbon monoxide, and ozone measurements were analyzed so as to establish how deeply tropospheric air mixes into the Arctic lowermost stratosphere and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to-stratosphere exchange extends into the Arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases with altitude most rapidly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of above 5ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20% of the parcels which have ozone values of 300-350 ppbv experiencing ice saturation in a given 10 day period. Third, during early spring, temperatures at the troposphere are cold enough so that 5-10% of parcels experience relative humidities above 100%, even if the water content is as low as 5 ppmv. The implication is that during this period, dynamical processes near the Arctic tropopause can dehydrate air and keep the Arctic tropopause region very dry during early spring.

Increased losses of organic carbon and destabilising of tropical peatlands following deforestation, drainage and burning. (Invited)

Science.gov (United States)

Moore, S.; Gauci, V.; Evans, C.; Page, S. E.

2013-12-01

Tropical peatlands contain one of the largest pools of terrestrial organic carbon, amounting to about 89,000 teragrams. Approximately 65% of this carbon store is in Indonesia, where extensive anthropogenic degradation in the form of deforestation, drainage and associated fire is converting it into a globally significant source of atmospheric carbon dioxide. Unlike boreal and temperate forests and higher-latitude wetlands, however, the loss of fluvial organic carbon from tropical peats has yet to be fully quantified. Here, we present the first data from intact and degraded peat swamp forest (PSF) catchments in Central Kalimantan, Borneo, that indicate a doubling of fluvial organic carbon losses from tropical peatlands following deforestation and drainage. Through carbon-14 dating of dissolved organic carbon (DO14C), we find that leaching of DOC from intact PSF is derived mainly from recent primary production. In contrast, DOC from disturbed PSF consists mostly of much older carbon from deep within the peat column. When we include this fluvial carbon loss, which is often ignored in peatland carbon budgets, we find that it increases the estimate of total carbon lost from the disturbed peatlands in our study by 22%. We further estimate that since 1990, peatland disturbance has resulted in a 32% increase in fluvial organic carbon flux from Southeast Asia - an increase that equates to more than half of the entire annual fluvial organic carbon flux from all European peatlands. Finally, we monitored fluvial organic carbon fluxes following large-scale peatland fires in 2009/10 within the study sub-catchments and found fluvial carbon fluxes to be 30-70% larger in the fire-affected catchments when compared to fluxes during the same interval in the previous year (pre-fire). This is in marked contrast to the intact catchment (control/no fire) where there were no differences observed in fluxes 'pre to post fire years'. Our sub-catchment findings were also found to be

Effect of N-Acetylcysteine in Protecting from Simultaneous Noise and Carbon Monoxide Induced Hair Cell Loss

Directory of Open Access Journals (Sweden)

Akram Pourbakht

2011-06-01

Full Text Available Background and Aim: N-acetylcysteine, a glutathione precursor and reactive oxygen species scavenger, is reported to be effective in reducing noise-induced hearing loss. Many workers in industry are exposed simultaneously to noise and chemical pollutants such as carbon monoxide. We investigated effectiveness of N-acetylcysteine in protecting the cochlea from simultaneous noise and carbon monoxide damages.Methods: Twelve rabbits were exposed simeltaneously to 100 dB sound pressure level of broad band noise and carbon monoxide 8 hours a day for 5 days. One hour before exposure, experimental group received 325 mg/kg of N-acetylcysteine while normal saline was administered for the control group. The protective effect of N-acetylcysteine was evaluated 3 weeks after exposure by histological assessment of the hair cells.Results: Simultaneous exposure to noise and carbon monoxide resulted in a considerable damage to the outer hair cells; however, the inner hair cells and the pillar cells remained intact. Use of N-acetylcysteine in the experimental group significantly reduced the extent of outer hair cell loss.Conclusion: N-acetylcysteine attenuates simultaneous noise and carbon monoxide induced hair cell damage in rabbits.

Large contribution of fossil fuel derived secondary organic carbon to water soluble organic aerosols in winter haze in China

Directory of Open Access Journals (Sweden)

Y.-L. Zhang

2018-03-01

Full Text Available Water-soluble organic carbon (WSOC is a large fraction of organic aerosols (OA globally and has significant impacts on climate and human health. The sources of WSOC remain very uncertain in polluted regions. Here we present a quantitative source apportionment of WSOC, isolated from aerosols in China using radiocarbon (14C and offline high-resolution time-of-flight aerosol mass spectrometer measurements. Fossil emissions on average accounted for 32–47 % of WSOC. Secondary organic carbon (SOC dominated both the non-fossil and fossil derived WSOC, highlighting the importance of secondary formation to WSOC in severe winter haze episodes. Contributions from fossil emissions to SOC were 61 ± 4 and 50 ± 9 % in Shanghai and Beijing, respectively, significantly larger than those in Guangzhou (36 ± 9 % and Xi'an (26 ± 9 %. The most important primary sources were biomass burning emissions, contributing 17–26 % of WSOC. The remaining primary sources such as coal combustion, cooking and traffic were generally very small but not negligible contributors, as coal combustion contribution could exceed 10 %. Taken together with earlier 14C source apportionment studies in urban, rural, semi-urban and background regions in Asia, Europe and the USA, we demonstrated a dominant contribution of non-fossil emissions (i.e., 75 ± 11 % to WSOC aerosols in the Northern Hemisphere; however, the fossil fraction is substantially larger in aerosols from East Asia and the eastern Asian pollution outflow, especially during winter, due to increasing coal combustion. Inclusion of our findings can improve a modelling of effects of WSOC aerosols on climate, atmospheric chemistry and public health.

The Emissions of Carbon Dioxide, Methane, and Nitrous Oxide during Winter without Cultivation in Local Saline-Alkali Rice and Maize Fields in Northeast China

Directory of Open Access Journals (Sweden)

Hao Zhang

2017-10-01

Full Text Available Agricultural ecosystems are important contributors to atmospheric greenhouse gasses (GHGs; however, in situ winter emission data in saline-alkali fields are scarce. Gas samples were collected during different periods, from three rice (R1–R3 and three maize (M1–M3 fields with different soil pH levels and salinity conditions. Carbon dioxide (CO2 emissions in the rice and maize fields decreased with decreasing temperature during the freezing period and increased with the rising temperature during the thawing period, with the majority of winter CO2 emissions occurring during these two periods. Peaks in methane (CH4 emissions were observed during the freezing period in the rice fields and during the snow-melting period in the rice and maize fields. CH4 emissions in the rice fields and CH4 uptake rates in the maize fields were significantly (P < 0.05 related to surface soil temperature. Nitrous oxide (N2O emissions remained relatively low, except for during the peaks observed during the snow-melting period in both the rice and maize fields, leading to the high GHG contribution of the snow-melting period throughout the winter. Higher pH and salinity conditions consistently resulted in lower CO2, CH4, and N2O emissions, CH4 uptake, and lower global warming potential (GWP. These results can contribute to the assessment of the GWP during winter in saline-alkali regions.

Effects of imidacloprid and clothianidin seed treatments on wheat aphids and their natural enemies on winter wheat.

Science.gov (United States)

Zhang, Peng; Zhang, Xuefeng; Zhao, Yunhe; Wei, Yan; Mu, Wei; Liu, Feng

2016-06-01

Wheat aphid (Hemiptera: Aphididae) is one of the major pests of winter wheat and has posed a significant threat to winter wheat production in China. Although neonicotinoid insecticidal seed treatments have been suggested to be a control method, the season-long efficacy on pests and the impact on their natural enemies are still uncertain. Experiments were conducted to determine the efficacy of imidacloprid and clothianidin on the control of aphids, the number of their natural enemies and the emergence rate and yield of wheat during 2011-2014. Imidacloprid and clothianidin seed treatments had no effect on the emergence rate of winter wheat and could prevent yield losses and wheat aphid infestations throughout the winter wheat growing season. Furthermore, their active ingredients were detected in winter wheat leaves up to 200 days after sowing. Imidacloprid and clothianidin seed treatments had no adverse effects on ladybirds, hoverflies or parasitoids, and instead increased the spider-aphid ratios. Wheat seeds treated with imidacloprid and clothianidin were effective against wheat aphids throughout the winter wheat growing season and reduced the yield loss under field conditions. Imidacloprid and clothianidin seed treatments may be an important component of the integrated management of wheat aphids on winter wheat. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

[Factors influencing ammonia volatilization in a winter wheat field with plastic film mulched ridges and unmulched furrows].

Science.gov (United States)

Shangguan, Yu-Xian; Shi, Ri-Peng; Li, Na; Han, Kun; Li, Hui-Ke; Wang, Lin-Quan

2012-06-01

The objective of this experiment was to quantify ammonia volatilization from a winter wheat field with plastic film mulched-ridges and unmulched-furrows (PMRF). The trial was conducted during the 2010-2011 winter wheat growing season at Yangling, Shaanxi Province. Ammonia volatilization from the soil was measured using the closed-chamber method. The results indicated that NH3 emission losses ranged between (1.66 +/- 0.3) and (3.28 +/- 0.51) kg x hm(-2) in the PMRF treatment. In comparison, the NH3 emission loss was (4.68 +/- 0.35) kg x ha(-1) in the conventional tillage treatment (i. e., smooth soil surface). The PMRF treatment reduced NH3 emissions by 29.8 to 63.8% compared with the conventional treatment. The NH3 emission losses were equivalent to 1.9% of the applied N in the conventional practice treatment. In contrast, the losses were equivalent to only 0.3% to 0.8% of the applied N in the PMRF treatment. Ammonia emissions were greatest during the first two weeks after sowing. Emissions before winter accounted for 82% of total NH3 emission in the conventional practice treatment, but only 49% to 61% of the total NH3 emission in the PMRF treatment. The soil NH4+ -N content and the soil moisture content had direct effects on NH3 emission before winter in the conventional treatment. In thePMRF treatment, the soil NH4+ -N content had a direct effect on NH3 emission before winter, whereas soil surface temperature and soil moisture had indirect effects. Ammonia emissions after the greening stage were mainly influenced by the soil NH4+ -N content. Simulation results indicated that logarithmic functions best described cumulative NH3 emission in the PMRF + high N rate treatment and the conventional treatment. A linear function best described cumulative NH3 emission in the PMRF + low N rate treatment and the unfertilized treatment. In conclusion, the PMRF treatment can significantly reduce N losses from winter wheat fields by changing the spatial-temporal dynamics of soil

Undernutrition and serum and urinary urea nitrogen of white-tailed deer during winter

Science.gov (United States)

DelGiudice, G.D.; Mech, L.D.; Seal, U.S.

1994-01-01

Direct, practical means of assessing undernutrition in deer (Odocoileus spp.) and other ungulates during winter are needed in areas of research and management. We examined the relationship between mass loss and serum urea nitrogen (SUN) and urinary urea nitrogen:creatinine (U:C) in captive white-tailed deer (O. virginianus). During 4 February-5 May 1988, we maintained 7 adult white-tailed deer on various feeding regimes to simulate natural nutritional restriction during winter. Mass loss was greater (P = 0.037) in deer (17.0-32.2%) fed restricted amounts of a low protein low energy diet versus control deer (7.0-17.4%) fed the same diet ad libitum. Serum triiodothyronine (T3) concentrations did not differ (P = 0.191) between groups, but declined (P = 0.001) as nutrition declined. Slopes of percent mass lossSUN and urinary U:C relationships were positive (P = 0.008 and 0.055) in 7 and 6 deer, respectively. Mean U:C was directly related (r2 = 0.52, P = 0.040) to mean cumulative mass loss, whereas mean SUN was not (r2 = 0.29, P = 0.125). Data presented support the potential of urinary U:C as an index of winter nutritional condition of white-tailed deer; however, additional research is required to provide a complete understanding of this index's utility under field conditions.

Carbon and greenhouse gas balance of the FR-GRI crop site from 2005 to 2014

Science.gov (United States)

Loubet, Benjamin; Chammakhi, Manel; Mascher, Nicolas; Durand, Brigitte; Gueudet, Jean-Christophe; Decuq, Céline; Lecuyer, Vanessa; Laville, Patricia; Buysse, Pauline; Cellier, Pierre

2017-04-01

The carbon and greenhouse gas balance of the ICOS FR-GRI site from 2005 to 2014 is presented. The site is a wheat-barley-maize rotation with the introduction of oil-seed rape in 2012. The site receives large amounts of organic fertilization, but is shown to be a strong source of carbon to the atmosphere, especially due to the increase in the exportations of residues during the period. The exportations have increased from around 4 to around 8 t C ha-1 year-1 over the period on average except for maize for which it remained constant. In the meantime the carbon importations have increased from around 1 to around 2 t C ha-1 year-1 during the same period. Overall the field was losing around 2 t C ha-1 year-1 over the whole period but largely driven by last years (2012-2014). This would represent 17% loss of the soil carbon content in the 0-60 cm in the 2005-2014 period. The discussion focuses on explanations of these losses and possible drawbacks in the methodology. The effect of the winter intermediate crops on the carbon balance is also discussed.

Carbon balance of the typical grain crop rotation in Moscow region assessed by eddy covariance method

Science.gov (United States)

Meshalkina, Joulia; Yaroslavtsev, Alexis; Vassenev, Ivan

2017-04-01

mustard; perhaps because the two crops were cultivated on the same field within one growing season. Other cases showed CO2 emission. NEE for barley field was equal to zero or even positive during the whole year; considering only the growing season, NEE for barley was about 100 g C m-2 lower and usually was negative. Carbon uptake for cereals was strongly related with weather conditions: in favorable years it was higher. Potato crop and cereal-legume mixture showed difference in 50-100 g C m-2 per year in NEE in different years related to difference in yields. The total agroecosystems respiration ranged from 400 to 550 g C m-2 per year and was closely linked to weather conditions. Closed balance for whole years showed that carbon losses were observed for all studied agroecosystems. It was minimal for fields with winter wheat, with mustard, used as green manure, and it was maximal for fields with cereal-legume mixture. Values about 200-250 g C m-2 per year may be considered as estimated values for the total carbon loss for the typical grain crop rotation in Moscow region. The use of mustard as a green manure reduced this value by three-quarters.

Energy loss of carbon transmitted 1-MeV H2+ ions

International Nuclear Information System (INIS)

Fritz, M.; Kimura, K.; Susuki, Y.; Mannami, M.

1994-01-01

Energy losses of 1-MeV H 2 + ions passing through carbon foils of 2-8 μg/cm 2 thickness have been measured and show besides the linear increase with target thickness a 0.4 keV offset. The stopping power derived from the observed energy losses is 1.15 times as large as the sum of the stopping powers for two single H + of the same velocity. Calculations of the stopping powers for H 2 + ions and diprotons, using first Born approximation, indicate that the H 2 + ions lose the binding electron upon entrance into the foil, traverse the target as diprotons and recapture target electrons at the exit surface, a scenario also supported by the 0.4 keV offset at zero thickness. (author)

Effects of Climatic Conditions and Management Practices on Agricultural Carbon and Water Budgets in the Inland Pacific Northwest USA

Science.gov (United States)

Chi, Jinshu; Waldo, Sarah; Pressley, Shelley N.; Russell, Eric S.; O'Keeffe, Patrick T.; Pan, William L.; Huggins, David R.; Stöckle, Claudio O.; Brooks, Erin S.; Lamb, Brian K.

2017-12-01

Cropland is an important land cover influencing global carbon and water cycles. Variability of agricultural carbon and water fluxes depends on crop species, management practices, soil characteristics, and climatic conditions. In the context of climate change, it is critical to quantify the long-term effects of these environmental drivers and farming activities on carbon and water dynamics. Twenty site-years of carbon and water fluxes covering a large precipitation gradient and a variety of crop species and management practices were measured in the inland Pacific Northwest using the eddy covariance method. The rain-fed fields were net carbon sinks, while the irrigated site was close to carbon neutral during the winter wheat crop years. Sites growing spring crops were either carbon sinks, sources, or neutral, varying with crops, rainfall zones, and tillage practices. Fluxes were more sensitive to variability in precipitation than temperature: annual carbon and water fluxes increased with the increasing precipitation while only respiration increased with temperature in the high-rainfall area. Compared to a nearby rain-fed site, irrigation improved winter wheat production but resulted in large losses of carbon and water to the atmosphere. Compared to conventional tillage, no-till had significantly lower respiration but resulted in slightly lower yields and water use efficiency over 4 years. Under future climate change, it is expected that more carbon fixation by crops and evapotranspiration would occur in a warmer and wetter environment.

Radiative losses and electron cooling rates for carbon and oxygen plasma impurities

International Nuclear Information System (INIS)

Marchand, R.; Bonnin, X.

1992-01-01

Radiative losses and electron cooling rates are calculated for carbon and oxygen ions under conditions relevant to fusion plasmas. Both rates are calculated with the most recent recommended atomic data. A modified coronal model which includes the effects of metastable states is described and used to calculate the rates. Comparisons with other approaches are also discussed. (author). 36 ref, figs

Nuclear Winter: Implications for civil defense

Energy Technology Data Exchange (ETDEWEB)

Chester, C.V.; Perry, A.M.; Hobbs, B.F.

1988-05-01

''Nuclear Winter'' is the term given to the cooling hypothesized to occur in the Northern Hemisphere following a nuclear war as the result of the injection of smoke from burning cities into the atmosphere. The voluminous literature on this subject produced since the paper was published in 1983 by Turco, Toon, Ackerman, Pollack, and Sagen (TTAPS) has been reviewed. Three-dimensional global circulation models have resulted in reduced estimates of cooling---15 to 25/degree/C for a summer war and a few degrees for a winter war. More serious may be the possibility of suppression of convective precipitation by the altered temperature profiles in the atmosphere. However, very large uncertainties remain in input parameters, the models, and the results of calculations. We believe the state of knowledge about nuclear winter is sufficiently developed to conclude: Neither cold nor drought is likely to be a direct threat to human survival for populations with the wherewithal to survive normal January temperatures. The principal threat from nuclear winter is to food production, and this could present problems to third parties who are without food reserves. Loss of a crop year is neither a new nor an unexpected threat from nuclear war to the United States and the Soviet Union. Both have at least a year's food reserve at all times. Both face formidable organizational problems in distributing their reserves in a war-damaged environment. The consequences of nuclear winter could be expected to fall more heavily on the Soviet Union than the United States due to its higher latitude and less productive agriculture. This may be especially true if disturbances of rainfall amounts and distribution persist for more than a year.

Does Wyoming's Core Area Policy Protect Winter Habitats for Greater Sage-Grouse?

Science.gov (United States)

Smith, Kurt T.; Beck, Jeffrey L.; Pratt, Aaron C.

2016-10-01

Conservation reserves established to protect important habitat for wildlife species are used world-wide as a wildlife conservation measure. Effective reserves must adequately protect year-round habitats to maintain wildlife populations. Wyoming's Sage-Grouse Core Area policy was established to protect breeding habitats for greater sage-grouse ( Centrocercus urophasianus). Protecting only one important seasonal habitat could result in loss or degradation of other important habitats and potential declines in local populations. The purpose of our study was to identify the timing of winter habitat use, the extent which individuals breeding in Core Areas used winter habitats, and develop resource selection functions to assess effectiveness of Core Areas in conserving sage-grouse winter habitats in portions of 5 Core Areas in central and north-central Wyoming during winters 2011-2015. We found that use of winter habitats occured over a longer period than current Core Area winter timing stipulations and a substantial amount of winter habitat outside of Core Areas was used by individuals that bred in Core Areas, particularly in smaller Core Areas. Resource selection functions for each study area indicated that sage-grouse were selecting habitats in response to landscapes dominated by big sagebrush and flatter topography similar to other research on sage-grouse winter habitat selection. The substantial portion of sage-grouse locations and predicted probability of selection during winter outside small Core Areas illustrate that winter requirements for sage-grouse are not adequately met by existing Core Areas. Consequently, further considerations for identifying and managing important winter sage-grouse habitats under Wyoming's Core Area Policy are warranted.

Oil sands mining and reclamation cause massive loss of peatland and stored carbon

Science.gov (United States)

Rooney, Rebecca C.; Bayley, Suzanne E.; Schindler, David W.

2012-01-01

We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services. PMID:22411786

Winter Survival of Individual Honey Bees and Honey Bee Colonies Depends on Level of Varroa destructor Infestation

NARCIS (Netherlands)

Dooremalen, van C.; Gerritsen, L.J.M.; Cornelissen, B.; Steen, van der J.J.M.; Langevelde, van F.; Blacquiere, T.

2012-01-01

Background: Recent elevated winter loss of honey bee colonies is a major concern. The presence of the mite Varroa destructor in colonies places an important pressure on bee health. V. destructor shortens the lifespan of individual bees, while long lifespan during winter is a primary requirement to

Contribution of allelopathy and competition to weed suppression by winter wheat, triticale and winter rye

DEFF Research Database (Denmark)

Reiss, Antje; Fomsgaard, Inge S.; Mathiassen, Solvejg Kopp

Above-ground competition and allelopathy are two of the most dominant mechanisms of plants to subdue their competitors in their closest surroundings. In an agricultural perspective, the suppression of weeds by the crop is of particular interest, as weeds represent the largest yield loss potential...... of competitive traits, such as early vigour, crop height and leaf area index and presence of phytotoxic compounds of the group of benzoxazinoids to weed suppression. Four cultivars of each of the winter cereals wheat, triticale and rye were grown in field experiments at two locations. Soil samples were taken...

Nuclear Winter: The implications for civil defense

International Nuclear Information System (INIS)

Chester, C.V.; Perry, A.M.; Hobbs, B.F.

1987-01-01

''Nuclear Winter'' is the term given to hypothesized cooling in the northern hemisphere following a nuclear war due to injection of smoke from burning cities into the atmosphere. The voluminous literature on this subject produced since the original paper in 1983 by Turco, Toon, Ackerman, Pollack, and Sagen (TTAPS) has been reviewed. The widespread use of 3-dimensional global circulation models have resulted in reduced estimates of cooling; 15 to 25 0 C for a summer war and a few degrees for a winter war. More serious may be the possibility of suppression of convective precipitation by the altered temperature profiles in the atmosphere. However, very large uncertainties remain in input parameters, the models, and the results of calculations. We believe the state of knowledge about nuclear winter is sufficiently developed to conclude: Neither cold nor drought are likely to be direct threats to human survival for populations with the wherewithal to survive normal January temperatures; The principal threat from nuclear winter is to food production, and could present problems to third parties without food reserves; and Loss of a crop year is neither a new nor unexpected threat from nuclear war to the US and the Soviet Union. Both have at least a year's food reserve at all times. Both face formidable organizational problems in distributing their reserves in a war-damaged environment. The consequences of nuclear winter could be expected to fall more heavily on the Soviet Union than the US due to its higher latitude and less productive agriculture. This may be especially true if disturbances of rainfall amounts and distribution persist for more than a year. 6 refs

Applying stochastic small-scale damage functions to German winter storms

Science.gov (United States)

Prahl, B. F.; Rybski, D.; Kropp, J. P.; Burghoff, O.; Held, H.

2012-03-01

Analyzing insurance-loss data we derive stochastic storm-damage functions for residential buildings. On district level we fit power-law relations between daily loss and maximum wind speed, typically spanning more than 4 orders of magnitude. The estimated exponents for 439 German districts roughly range from 8 to 12. In addition, we find correlations among the parameters and socio-demographic data, which we employ in a simplified parametrization of the damage function with just 3 independent parameters for each district. A Monte Carlo method is used to generate loss estimates and confidence bounds of daily and annual storm damages in Germany. Our approach reproduces the annual progression of winter storm losses and enables to estimate daily losses over a wide range of magnitudes.

Carbon sequestration in the agroecosystem

Directory of Open Access Journals (Sweden)

Tomáš Středa

2008-01-01

Full Text Available Reduction of amount CO2 is possible by carbon sequestration to the soil. Fixation potential of EU–15 agricultural land is c. 16–19 mil t C . year−1. Amount and composition of post–harvest residues is essential for carbon soil sequestration. Long–term yield series of the most planted crops (winter wheat – Triticum aestivum, spring barley – Hordeum vulgare, corn and silage maize – Zea mays, winter rape – Brassica napus, potatoes – Solanum tuberosum, sugar beet – Beta vulgaris, alfalfa – Medicago sativa, red clover – Trifolium pratense, white mustard – Sinapis alba and fiddleneck – Phacelia tanacetifolia in various agroecological conditions and growing technologies were used for carbon balance calculation. The carbon balances were calculated for main crop rotations of maize, sugar beet, cereal and potato production regions (24 crop rotations. The calculations were realized for following planting varieties: traditional, commercial, ecological and with higher rate of winter rape. All chosen crop rotations (except seven have positive carbon balance in the tillage system. Amount of fixed carbon might be increases about 30% by the use of no–tillage system. Least amount of carbon is fixed by potatoes, high amount by cereals, alfalfa and sugar beet. For a short time (months the crops sequestration of carbon is relatively high (to 4.4 t . ha−1 . year−1 or to 5.7 t . ha−1 . year−1 for no–tillage system. From the long time viewpoint (tens of years the data of humified carbon in arable soil (max 400 kg C . ha−1 . year−1 are important. Maximal carbon deficit of chosen crop rotation is 725 kg C . year−1.

Determining contributions of biomass burning and other sources to fine particle contemporary carbon in the western United States

Science.gov (United States)

Holden, Amanda S.; Sullivan, Amy P.; Munchak, Leigh A.; Kreidenweis, Sonia M.; Schichtel, Bret A.; Malm, William C.; Collett, Jeffrey L., Jr.

2011-02-01

Six-day integrated fine particle samples were collected at urban and rural sampling sites using Hi-Volume samplers during winter and summer 2004-2005 as part of the IMPROVE (Interagency Monitoring of PROtected Visual Environments) Radiocarbon Study. Filter samples from six sites (Grand Canyon, Mount Rainier, Phoenix, Puget Sound, Rocky Mountain National Park, and Tonto National Monument) were analyzed for levoglucosan, a tracer for biomass combustion, and other species by High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). Contemporary carbon concentrations were available from previous carbon isotope measurements at Lawrence Livermore National Laboratory. Primary contributions of biomass burning to measured fine particle contemporary carbon were estimated for residential wood burning (winter) and wild/prescribed fires (summer). Calculated contributions ranged from below detection limit to more than 100% and were typically higher at rural sites and during winter. Mannitol, a sugar alcohol emitted by fungal spores, was analyzed and used to determine contributions of fungal spores to fine particle contemporary carbon. Contributions reached up to 13% in summer samples, with higher contributions at rural sites. Concentrations of methyltetrols, oxidation products of isoprene, were also measured by HPAEC-PAD. Secondary organic aerosol (SOA) from isoprene oxidation was estimated to contribute up to 22% of measured contemporary carbon. For each sampling site, a substantial portion of the contemporary carbon was unexplained by primary biomass combustion, fungal spores, or SOA from isoprene oxidation. This unexplained fraction likely contains contributions from other SOA sources, including oxidation products of primary smoke emissions and plant emissions other than isoprene, as well as other primary particle emissions from meat cooking, plant debris, other biological aerosol particles, bio-diesel combustion, and other sources. Loss

Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

Science.gov (United States)

Martinez, Amos; Al Araimi, Mohammed; Dmitriev, Artemiy; Lutsyk, Petro; Li, Shen; Mou, Chengbo; Rozhin, Alexey; Sumetsky, Misha; Turitsyn, Sergei

2017-12-01

The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors) and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50%) and poor saturable to non-saturable absorption ratios (typically above 1:5). In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%), and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

Ice Algae-Produced Carbon Is Critical for Overwintering of Antarctic Krill Euphausia superba

Directory of Open Access Journals (Sweden)

Doreen Kohlbach

2017-09-01

Full Text Available Antarctic krill Euphausia superba (“krill” constitute a fundamental food source for Antarctic seabirds and mammals, and a globally important fisheries resource. The future resilience of krill to climate change depends critically on the winter survival of young krill. To survive periods of extremely low production by pelagic algae during winter, krill are assumed to rely partly on carbon produced by ice algae. The true dependency on ice algae-produced carbon, however, is so far unquantified. This confounds predictions on the future resilience of krill stocks to sea ice decline. Fatty acid (FA analysis, bulk stable isotope analysis (BSIA, and compound-specific stable isotope analysis (CSIA of diatom- and dinoflagellate-associated marker FAs were applied to quantify the dependency of overwintering larval, juvenile, and adult krill on ice algae-produced carbon (αIce during winter 2013 in the Weddell-Scotia Confluence Zone. Our results demonstrate that the majority of the carbon uptake of the overwintering larval and juvenile krill originated from ice algae (up to 88% of the carbon budget, and that the dependency on ice algal carbon decreased with ontogeny, reaching <56% of the carbon budget in adults. Spatio-temporal variability in the utilization of ice algal carbon was more pronounced in larvae and juvenile krill than in adults. Differences between αIce estimates derived from short- vs. long-term FA-specific isotopic compositions suggested that ice algae-produced carbon gained importance as the winter progressed, and might become critical at the late winter-spring transition, before the phytoplankton bloom commences. Where the sea ice season shortens, reduced availability of ice algae might possibly not be compensated by surplus phytoplankton production during wintertime. Hence, sea ice decline could seriously endanger the winter survival of recruits, and subsequently overall biomass of krill.

Preparations for Severe Winter Conditions by Emergency Health Personnel in Turkey.

Science.gov (United States)

Calışkan, Cüneyt; Algan, Aysun; Koçak, Hüseyin; Biçer, Burcu Küçük; Sengelen, Meltem; Cakir, Banu

2014-04-23

Emergency and core ambulance personnel work under all environmental conditions, including severe weather condtions. We evaluated emergency medical personnel in Çanakkale, Turkey, for their degree of preparedness. A descriptive study was conducted in Çanakkale, Turkey, within 112 emergency service units and their 17 district stations. Surveys were developed to measure the level of preparedness for serious winter conditions that individual workers made for themselves, their homes, and their cars. Of the 167 survey participants, the mean age was 29.8 ± 7.9 years; 52.7% were women; more than half (54.75%) were emergency medical technicians; and 53.3% were married. Only 10.4% of those who heated their homes with natural gas had carbon monoxide detectors. Scores relating to household and individual preparation for severe winter conditions increased by participants' age (P tires (P winter conditions (P = .016). Many of the surveyed emergency health personel demonstrated insufficient preparations for serious winter conditions. To increase the safety and efficiency of emergency medical personnel, educational training programs should be rountinely conducted. (Disaster Med Public Health Preparedness. 2014;0:1-4).

Winter-regime surface heat loss from heated streams

International Nuclear Information System (INIS)

Paily, P.P.; Macagno, E.O.; Kennedy, J.F.

1974-01-01

Evaluation of the rate of surface heat exchange between the water and air is a significant factor in any study of the thermal response of heated streams to heat inputs. Existing methods to determine the amount of heat transfer across the water surface are surveyed, and the different formulas developed for determining the heat exchange components are compiled. Heat-transfer models that have been proposed in the literature are reviewed, and a new linearized model for determining the rate of surface heat exchange is proposed. Generalized relations between the major climatological factors and the coefficients of the linearized heat-loss rate are established by multiple-regression analysis. The analysis is limited to cold-period conditions, in the sense that air temperatures below the freezing point of water only are considered in developing the regression equations. A computer program, using FORTRAN, is presented which enables the computation of the coefficients appearing in the linearized heat-loss rate for all combinations of the various climatological factors

Quantitative geochemical modeling along a transect off Peru: Carbon cycling in time and space, and the triggering factors for carbon loss and storage

Science.gov (United States)

Arning, Esther T.; van Berk, Wolfgang; Schulz, Hans-Martin

2012-12-01

Early diagenetic processes in Peruvian shelf and slope sediments are numerically reproduced by applying chemical thermodynamics in a complex, universal approach using the PHREEQC (version 2) computer code. The reaction kinetics of organic carbon remineralization are integrated into a set of equilibrium reactions by defining the type and the amount of converted organic matter in a certain time step. We calculate the most intense remineralization of organic carbon for present-day shelf sites, and the final carbon pool is dominated by secondary carbonates. This serves to highlight the influence of organic matter degradation and anaerobic oxidation of methane (AOM) on diagenetic mineral formation. The enrichment of aqueous methane and the formation of methane hydrate only takes place in slope sediments with high sedimentation rates that prevent diffusive loss of methane (e.g., Sites 682 and 688). Moreover, AOM prevents the diffusion of dissolved methane into overlying seawater. Throughout the Miocene period, these sites were located on a former shelf and the total carbon loss from the sediments was significantly higher in comparison with the present-day. Compared with the present-day shelf site, organic matter remineralization is high, and methane is produced but not stored within the sediments. Our model calculations rule out the possibility of present-day and former shelf site sediments off the coast of Peru as methane reservoirs. Remineralized TOC has to be considered, particularly in older sediments, when interpreting TOC profiles and calculating mass accumulation rates of total organic carbon (MARTOC). The more organic matter has been remineralized during the depositional history, the larger the difference between MARTOC calculated from measured TOC data, and from the sum of modeled and measured TOC data. Consequently, most reliable primary productivity calculations are based on the sum of measured relict TOC and the amount of remineralized organic carbon

The influence of winter convection on primary production: A parameterisation using a hydrostatic three-dimensional biogeochemical model

DEFF Research Database (Denmark)

Grosse, Fabian; Lindemann, Christian; Pätch, Johannes

2014-01-01

organic carbon. The carbon export during late winter/early spring significantly exceeded the export of the reference run. Furthermore, a non-hydrostatic convection model was used to evaluate the major assumption of the presented parameterisation which implies the matching of the mixed layer depth...

Quantifying the Impact of Seasonal and Short-term Manure Application Decisions on Phosphorus Loss in Surface Runoff.

Science.gov (United States)

Vadas, Peter A; Good, Laura W; Jokela, William E; Karthikeyan, K G; Arriaga, Francisco J; Stock, Melanie

2017-11-01

Agricultural phosphorus (P) management is a research and policy issue due to P loss from fields and water quality degradation. Better information is needed on the risk of P loss from dairy manure applied in winter or when runoff is imminent. We used the SurPhos computer model and 108 site-years of weather and runoff data to assess the impact of these two practices on dissolved P loss. Model results showed that winter manure application can increase P loss by 2.5 to 3.6 times compared with non-winter applications, with the amount increasing as the average runoff from a field increases. Increased P loss is true for manure applied any time from late November through early March, with a maximum P loss from application in late January and early February. Shifting manure application to fields with less runoff can reduce P loss by 3.4 to 7.5 times. Delaying manure application when runoff is imminent can reduce P loss any time of the year, and sometimes quite significantly, but the number of times that application delays will reduce P loss is limited to only 3 to 9% of possible spreading days, and average P loss may be reduced by only 15% for winter-applied manure and 6% for non-winter-applied manure. Overall, long-term strategies of shifting manure applications to low runoff seasons and fields can potentially reduce dissolved P loss in runoff much more compared with near-term, tactical application decisions of avoiding manure application when runoff is imminent. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Ice fishing by wintering Bald Eagles in Arizona

Science.gov (United States)

Teryl G. Grubb; Roy G. Lopez

1997-01-01

Northern Arizona winters vary within and between years with occasional heavy snows (up to 0.6 m) and extreme cold (overnight lows -18 to -29°C) interspersed with dry periods, mild temperatures (daytime highs reaching 10°C), and general loss of snow cover at all but highest elevations. Lakes in the area may freeze and thaw partially or totally several times during a...

Energy utilization, carbon dioxide emission, and exergy loss in flavored yogurt production process

International Nuclear Information System (INIS)

Sorgüven, Esra; Özilgen, Mustafa

2012-01-01

This paper investigates the impact of food production processes on the environment in terms of energy and exergy utilization and carbon dioxide emission. There are three different energy utilization mechanisms in food production: Utilization of solar energy by plants to produce agricultural goods; feed consumption by herbivores to produce meat and milk; fossil fuel consumption by industrial processes to perform mixing, cooling, heating, etc. Production of strawberry-flavored yogurt, which involves these three mechanisms, is investigated here thermodynamically. Analysis starts with the cultivation of the ingredients and ends with the transfer of the final product to the market. The results show that 53% of the total exergy loss occurs during the milk production and 80% of the total work input is consumed during the plain yogurt making. The cumulative degree of perfection is 3.6% for the strawberry-flavored yogurt. This value can rise up to 4.6%, if renewable energy resources like hydropower and algal biodiesel are employed instead of fossil fuels. This paper points the direction for the development of new technology in food processing to decrease waste of energy and carbon dioxide accumulation in the atmosphere. -- Highlights: ► Energy and exergy utilization and carbon dioxide emission during strawberry-flavored yogurt production. ► Cumulative degree of perfection of strawberry-flavored yogurt is 3.6%. ► 53% of the total exergy loss occurs during the milk production. ► 80% of the total work input is consumed during the plain yogurt making.

Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw and increased groundwater discharge

Science.gov (United States)

O'Donnell, Jonathan A.; Aiken, George R.; Walvoord, Michelle Ann; Butler, Kenna D.

2012-01-01

Groundwater discharge to rivers has increased in recent decades across the circumpolar region and has been attributed to thawing permafrost in arctic and subarctic watersheds. Permafrost-driven changes in groundwater discharge will alter the flux of dissolved organic carbon (DOC) in rivers, yet little is known about the chemical composition and reactivity of dissolved organic matter (DOM) of groundwater in permafrost settings. Here, we characterize DOM composition of winter flow in 60 rivers and streams of the Yukon River basin to evaluate the biogeochemical consequences of enhanced groundwater discharge associated with permafrost thaw. DOC concentration of winter flow averaged 3.9 ± 0.5 mg C L−1, yet was highly variable across basins (ranging from 20 mg C L−1). In comparison to the summer-autumn period, DOM composition of winter flow had lower aromaticity (as indicated by specific ultraviolet absorbance at 254 nm, or SUVA254), lower hydrophobic acid content, and a higher proportion of hydrophilic compounds (HPI). Fluorescence spectroscopy and parallel factor analysis indicated enrichment of protein-like fluorophores in some, but not all, winter flow samples. The ratio of DOC to dissolved organic nitrogen, an indicator of DOM biodegradability, was positively correlated with SUVA254 and negatively correlated with the percentage of protein-like compounds. Using a simple two-pool mixing model, we evaluate possible changes in DOM during the summer-autumn period across a range of conditions reflecting possible increases in groundwater discharge. Across three watersheds, we consistently observed decreases in DOC concentration and SUVA254 and increases in HPI with increasing groundwater discharge. Spatial patterns in DOM composition of winter flow appear to reflect differences in the relative contributions of groundwater from suprapermafrost and subpermafrost aquifers across watersheds. Our findings call for more explicit consideration of DOC loss and stabilization

Winters fuels report

International Nuclear Information System (INIS)

1995-01-01

The outlook for distillate fuel oil this winter is for increased demand and a return to normal inventory patterns, assuming a resumption of normal, cooler weather than last winter. With industrial production expected to grow slightly from last winter's pace, overall consumption is projected to increase 3 percent from last winter, to 3.4 million barrels per day during the heating season (October 1, 1995-March 31, 1996). Much of the supply win come from stock drawdowns and refinery production. Estimates for the winter are from the Energy Information Administration's (EIA) 4th Quarter 1995 Short-Tenn Energy Outlook (STEO) Mid-World Oil Price Case forecast. Inventories in place on September 30, 1995, of 132 million barrels were 9 percent below the unusually high year-earlier level. Inventories of high-sulfur distillate fuel oil, the principal type used for heating, were 13 percent lower than a year earlier. Supply problems are not anticipated because refinery production and the ready availability of imports should be adequate to meet demand. Residential heating off prices are expected to be somewhat higher than last winter's, as the effects of lower crude oil prices are offset by lower distillate inventories. Heating oil is forecast to average $0.92 per gallon, the highest price since the winter of 1992-93. Diesel fuel (including tax) is predicted to be slightly higher than last year at $1.13 per gallon. This article focuses on the winter assessment for distillate fuel oil, how well last year's STEO winter outlook compared to actual events, and expectations for the coming winter. Additional analyses include regional low-sulfur and high-sulfur distillate supply, demand, and prices, and recent trends in distillate fuel oil inventories

Campaign to prevent carbon monoxide poisoning : fall-winter 2007-2008

International Nuclear Information System (INIS)

Lefebvre, B.; Chabot, L.; Gratton, J.; Lacoursiere, D.

2009-01-01

Quebec launched a public health campaign for the Montreal region to prevent carbon monoxide poisoning. The objectives of the campaign were to communicate the dangers of carbon monoxide poisoning, its potential sources, its effects on public health, and the means to prevent poisoning. Its purpose was to inform the public of the risks and strategies to be used in case of carbon monoxide poisoning and to lay out the merits of household carbon monoxide alarms. The communication was done by way of the media, in cooperation with community organizations and school boards. Other tools used in the campaign included the Internet, flyers and press releases. A poll taken in 2008 showed that 59 per cent of the respondents had one or more sources for carbon monoxide in their homes, including fireplaces, and that 28 per cent had a functioning alarm for carbon monoxide detection. A future survey will be held to follow-up on the evolution of the campaign. The development of various activities will help decrease the risk of carbon monoxide poisoning. tabs., figs.

Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

Directory of Open Access Journals (Sweden)

Amos Martinez

2017-12-01

Full Text Available The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50% and poor saturable to non-saturable absorption ratios (typically above 1:5. In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%, and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

Diurnal Variation in Gas Exchange: The Balance between Carbon Fixation and Water Loss.

Science.gov (United States)

Matthews, Jack S A; Vialet-Chabrand, Silvere R M; Lawson, Tracy

2017-06-01

Stomatal control of transpiration is critical for maintaining important processes, such as plant water status, leaf temperature, as well as permitting sufficient CO 2 diffusion into the leaf to maintain photosynthetic rates ( A ). Stomatal conductance often closely correlates with A and is thought to control the balance between water loss and carbon gain. It has been suggested that a mesophyll-driven signal coordinates A and stomatal conductance responses to maintain this relationship; however, the signal has yet to be fully elucidated. Despite this correlation under stable environmental conditions, the responses of both parameters vary spatially and temporally and are dependent on species, environment, and plant water status. Most current models neglect these aspects of gas exchange, although it is clear that they play a vital role in the balance of carbon fixation and water loss. Future efforts should consider the dynamic nature of whole-plant gas exchange and how it represents much more than the sum of its individual leaf-level components, and they should take into consideration the long-term effect on gas exchange over time. © 2017 American Society of Plant Biologists. All Rights Reserved.

Winter to winter recurrence of atmospheric circulation anomalies over East Asia and its impact on winter surface air temperature anomalies.

Science.gov (United States)

Zhao, Xia; Yang, Guang

2017-01-01

The persistence of atmospheric circulation anomalies over East Asia shows a winter to winter recurrence (WTWR) phenomenon. Seasonal variations in sea level pressure anomalies and surface wind anomalies display significantly different characteristics between WTWR and non-WTWR years. The WTWR years are characterized by the recurrence of both a strong (weak) anomalous Siberian High and an East Asian winter monsoon over two successive winters without persistence through the intervening summer. However, anomalies during the non-WTWR years have the opposite sign between the current and ensuing winters. The WTWR of circulation anomalies contributes to that of surface air temperature anomalies (SATAs), which is useful information for improving seasonal and interannual climate predictions over East Asia and China. In the positive (negative) WTWR years, SATAs are cooler (warmer) over East Asia in two successive winters, but the signs of the SATAs are opposite in the preceding and subsequent winters during the non-WTWR years.

Electron energy-loss spectroscopy characterization and microwave absorption of iron-filled carbon-nitrogen nanotubes

International Nuclear Information System (INIS)

Che Renchao; Liang Chongyun; Shi Honglong; Zhou Xingui; Yang Xinan

2007-01-01

Iron-filled carbon-nitrogen (Fe/CN x ) nanotubes and iron-filled carbon (Fe/C) nanotubes were synthesized at 900 deg. C through a pyrolysis reaction of ferrocene/acetonitrile and ferrocene/xylene, respectively. The differences of structure and composition between the Fe/CN x nanotubes and Fe/C nanotubes were investigated by transmission electron microscopy and electron energy-loss spectroscopy (EELS). It was found that the morphology of Fe/CN x nanotubes is more corrugated than that of the Fe/C nanotubes due to the incorporation of nitrogen. By comparing the Fe L 2,3 electron energy-loss spectra of Fe/CN x nanotubes to those of the Fe/C nanotubes, the electron states at the interface between Fe and the tubular wall of both Fe/CN x nanotubes and Fe/C nanotubes were investigated. At the boundary between Fe and the wall of a CN x nanotube, the additional electrons contributed from the doped 'pyridinic-like' nitrogen might transfer to the empty 3d orbital of the encapsulated iron, therefore leading to an intensity suppression of the iron L 2,3 edge and an intensity enhancement of the carbon K edge. However, such an effect could not be found in Fe/C nanotubes. Microwave absorption properties of both Fe/CN x and Fe/C nanocomposites at 2-18 GHz band were studied

Tillage effects on N2O emissions as influenced by a winter cover crop

DEFF Research Database (Denmark)

Petersen, Søren O; Mutegi, James; Hansen, Elly Møller

2011-01-01

emissions may be more important than the effect on soil C. This study monitored emissions of N2O between September 2008 and May 2009 in three tillage treatments, i.e., conventional tillage (CT), reduced tillage (RT) and direct drilling (DD), all with (+CC) or without (−CC) fodder radish as a winter cover...... application by direct injection N2O emissions were stimulated in all tillage treatments, reaching 250–400 μg N m−2 h−1 except in the CT + CC treatment, where emissions peaked at 900 μg N m−2 h−1. Accumulated emissions ranged from 1.6 to 3.9 kg N2O ha−1. A strong positive interaction between cover crop......Conservation tillage practices are widely used to protect against soil erosion and soil C losses, whereas winter cover crops are used mainly to protect against N losses during autumn and winter. For the greenhouse gas balance of a cropping system the effect of reduced tillage and cover crops on N2O...

Seagrass blue carbon dynamics in the Gulf of Mexico: Stocks, losses from anthropogenic disturbance, and gains through seagrass restoration.

Science.gov (United States)

Thorhaug, Anitra; Poulos, Helen M; López-Portillo, Jorge; Ku, Timothy C W; Berlyn, Graeme P

2017-12-15

Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimentary carbon from seagrass restoration are lacking for most of the Western Hemisphere. To begin to fill this knowledge gap in the subtropics and tropics, we quantified organic carbon (C org ) stocks, losses, and gains from restorations at 8 previously-disturbed seagrass sites around the Gulf of Mexico (GoM) (n=128 cores). Mean natural seagrass C org stocks were 25.7±6.7MgC org ha -1 around the GoM, while mean C org stocks at adjacent barren sites that had previously hosted seagrass were 17.8MgC org ha -1 . Restored seagrass beds contained a mean of 38.7±13.1MgC org ha -1 . Mean C org losses differed by anthropogenic impact type, but averaged 20.98±7.14MgC org ha -1 . C org gains from seagrass restoration averaged 20.96±8.59Mgha -1 . These results, when combined with the similarity between natural and restored C org content, highlight the potential of seagrass restoration for mitigating seagrass C org losses from prior impact events. Our GoM basin-wide estimates of natural C org totaled ~36.4Tg for the 947,327ha for the USA-GoM. Including Mexico, the total basin contained an estimated 37.2-37.5Tg C org . Regional US-GoM losses totaled 21.69Tg C org . C org losses differed significantly among anthropogenic impacts. Yet, seagrass restoration appears to be an important climate change mitigation strategy that could be implemented elsewhere throughout the tropics and subtropics. Copyright © 2017 Elsevier B.V. All rights reserved.

Reproductive success and failure: the role of winter body mass in reproductive allocation in Norwegian moose.

Science.gov (United States)

Milner, Jos M; van Beest, Floris M; Solberg, Erling J; Storaas, Torstein

2013-08-01

A life history strategy that favours somatic growth over reproduction is well known for long-lived iteroparous species, especially in unpredictable environments. Risk-sensitive female reproductive allocation can be achieved by a reduced reproductive effort at conception, or the subsequent adjustment of investment during gestation or lactation in response to unexpected environmental conditions or resource availability. We investigated the relative importance of reduced investment at conception compared with later in the reproductive cycle (i.e. prenatal, perinatal or neonatal mortality) in explaining reproductive failure in two high-density moose (Alces alces) populations in southern Norway. We followed 65 multiparous, global positioning system (GPS)-collared females throughout the reproductive cycle and focused on the role of maternal nutrition during gestation in determining reproductive success using a quasi-experimental approach to manipulate winter forage availability. Pregnancy rates in early winter were normal (≥0.8) in all years while spring calving rates ranged from 0.4 to 0.83, with prenatal mortality accounting for most of the difference. Further losses over summer reduced autumn recruitment rates to 0.23-0.69, despite negligible predation. Over-winter mass loss explained variation in both spring calving and autumn recruitment success better than absolute body mass in early or late winter. Although pregnancy was related to body mass in early winter, overall reproductive success was unrelated to pre-winter body condition. We therefore concluded that reproductive success was limited by winter nutritional conditions. However, we could not determine whether the observed reproductive allocation adjustment was a bet-hedging strategy to maximise reproduction without compromising survival or whether females were simply unable to invest more resources in their offspring.

Establishing Winter Origins of Migrating Lesser Snow Geese Using Stable Isotopes

Directory of Open Access Journals (Sweden)

Viviane Hénaux

2012-06-01

Full Text Available Increases in Snow Goose (Chen caerulescens populations and large-scale habitat changes in North America have contributed to the concentration of migratory waterfowl on fewer wetlands, reducing resource availability, and enhancing risks of disease transmission. Predicting wintering locations of migratory individuals is critical to guide wildlife population management and habitat restoration. We used stable carbon (δ13C, nitrogen (δ15N, and hydrogen (δ2H isotope ratios in muscle tissue of wintering Snow Geese to discriminate four major wintering areas, the Playa Lake Region, Texas Gulf Coast, Louisiana Gulf Coast, and Arkansas, and infer the wintering locations of individuals collected later during the 2007 and 2008 spring migrations in the Rainwater Basin (RWB of Nebraska. We predicted the wintering ground derivation of migrating Snow Geese using a likelihood-based approach. Our three-isotope analysis provided an efficient discrimination of the four wintering areas. The assignment model predicted that 53% [95% CI: 37-69] of our sample of Snow Geese from the RWB in 2007 had most likely originated in Louisiana, 38% [23-54] had wintered on Texas Gulf Coast, and 9% [0-20] in Arkansas; the assessment suggested that 89% [73-100] of our 2008 sample had most likely come from Texas Gulf Coast, 9% [0-27] from Louisiana Gulf Coast, and 2% [0-9] from Arkansas. Further segregation of wintering grounds and additional sampling of spring migrating Snow Geese would refine overall assignment and help explain interannual variations in migratory connectivity. The ability to distinguish origins of northbound geese can support the development of spatially-adaptive management strategies for the midcontinent Snow Goose population. Establishing migratory connectivity using isotope assignment techniques can be extended to other waterfowl species to determine critical habitat, evaluate population energy requirements, and inform waterfowl conservation and management

Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere

OpenAIRE

Cleveland, Cory C.; Townsend, Alan R.

2006-01-01

Terrestrial biosphere–atmosphere carbon dioxide (CO2) exchange is dominated by tropical forests, where photosynthetic carbon (C) uptake is thought to be phosphorus (P)-limited. In P-poor tropical forests, P may also limit organic matter decomposition and soil C losses. We conducted a field-fertilization experiment to show that P fertilization stimulates soil respiration in a lowland tropical rain forest in Costa Rica. In the early wet season, when soluble organic matter inputs to soil are hig...

Assessment of weather-associated causes of red spruce winter injury and consequences to aboveground carbon sequestration

Science.gov (United States)

Paul G. Schaberg; Brynne E. Lazarus; Gary J. Hawley; Joshua M. Halman; Catherine H. Borer; Christopher F. Hansen

2011-01-01

Despite considerable study, it remains uncertain what environmental factors contribute to red spruce (Picea rubens Sarg.) foliar winter injury and how much this injury influences tree C stores. We used a long-term record of winter injury in a plantation in New Hampshire and conducted stepwise linear regression analyses with local weather and regional...

Nitrogen, phosphorus and carbon excretion and losses in growing pigs fed Danish or Asian diets

DEFF Research Database (Denmark)

Prapaspongsa, Trakarn; Vu, Van Thi Khanh; Poulsen, Hanne Damgaard

2008-01-01

The objectives of this study were to determine inputs and outputs of nitrogen (N), phosphorus (P) and carbon (C) and to estimate the nutrient losses during housing and storage in order to address these important parts of the whole manure management systems in pigs fed different diets....

Distribution pattern of picoplankton carbon biomass linked to mesoscale dynamics in the southern gulf of Mexico during winter conditions

Science.gov (United States)

Linacre, Lorena; Lara-Lara, Rubén; Camacho-Ibar, Víctor; Herguera, Juan Carlos; Bazán-Guzmán, Carmen; Ferreira-Bartrina, Vicente

2015-12-01

In order to characterize the carbon biomass spatial distribution of autotrophic and heterotrophic picoplankton populations linked to mesoscale dynamics, an investigation over an extensive open-ocean region of the southern Gulf of Mexico (GM) was conducted. Seawater samples from the mixed layer were collected during wintertime (February-March 2013). Picoplankton populations were counted and sorted using flow cytometry analyses. Carbon biomass was assessed based on in situ cell abundances and conversion factors from the literature. Approximately 46% of the total picoplankton biomass was composed of three autotrophic populations (Prochlorococcus, Synechococcus, and pico-eukaryotes), while 54% consisted of heterotrophic bacteria populations. Prochlorococcus spp. was the most abundant pico-primary producer (>80%), and accounted for more than 60% of the total pico-autotrophic biomass. The distribution patterns of picoplankton biomass were strongly associated with the mesoscale dynamics that modulated the hydrographic conditions of the surface mixed layer. The main features of the carbon distribution pattern were: (1) the deepening of picoplankton biomass to layers closer to the nitracline base in anticyclonic eddies; (2) the shoaling of picoplankton biomass in cyclonic eddies, constraining the autoprokaryote biomasses to the upper layers, as well as accumulating the pico-eukaryote biomass in the cold core of the eddies; and (3) the increase of heterotrophic bacteria biomass in frontal regions between counter-paired anticyclonic and cyclonic eddies. Factors related to nutrient preferences and light conditions may as well have contributed to the distribution pattern of the microbial populations. The findings reveal the great influence of the mesoscale dynamics on the distribution of picoplankton populations within the mixed layer. Moreover, the significance of microbial components (especially Prochlorococcus) in the southern GM during winter conditions was revealed

Chemical composition, sources, and aging process of submicron aerosols in Beijing: Contrast between summer and winter

Science.gov (United States)

Hu, Weiwei; Hu, Min; Hu, Wei; Jimenez, Jose L.; Yuan, Bin; Chen, Wentai; Wang, Ming; Wu, Yusheng; Chen, Chen; Wang, Zhibin; Peng, Jianfei; Zeng, Limin; Shao, Min

2016-02-01

To investigate the seasonal characteristics of submicron aerosol (PM1) in Beijing urban areas, a high-resolution time-of-flight aerosol-mass-spectrometer (HR-ToF-AMS) was utilized at an urban site in summer (August to September 2011) and winter (November to December 2010), coupled with multiple state of the art online instruments. The average mass concentrations of PM1 (60-84 µg m-3) and its chemical compositions in different campaigns of Beijing were relatively consistent in recent years. In summer, the daily variations of PM1 mass concentrations were stable and repeatable. Eighty-two percent of the PM1 mass concentration on average was composed of secondary species, where 62% is secondary inorganic aerosol and 20% secondary organic aerosol (SOA). In winter, PM1 mass concentrations changed dramatically because of the different meteorological conditions. The high average fraction (58%) of primary species in PM1 including primary organic aerosol (POA), black carbon, and chloride indicates primary emissions usually played a more important role in the winter. However, aqueous chemistry resulting in efficient secondary formation during occasional periods with high relative humidity may also contribute substantially to haze in winter. Results of past OA source apportionment studies in Beijing show 45-67% of OA in summer and 22-50% of OA in winter can be composed of SOA. Based on the source apportionment results, we found 45% POA in winter and 61% POA in summer are from nonfossil sources, contributed by cooking OA in both seasons and biomass burning OA (BBOA) in winter. Cooking OA, accounting for 13-24% of OA, is an important nonfossil carbon source in all years of Beijing and should not be neglected. The fossil sources of POA include hydrocarbon-like OA from vehicle emissions in both seasons and coal combustion OA (CCOA) in winter. The CCOA and BBOA were the two main contributors (57% of OA) for the highest OA concentrations (>100 µg m-3) in winter. The POA

Field Evaluation of Highly Insulating Windows in the Lab Homes: Winter Experiment

Energy Technology Data Exchange (ETDEWEB)

Parker, Graham B.; Widder, Sarah H.; Bauman, Nathan N.

2012-06-01

This field evaluation of highly insulating windows was undertaken in a matched pair of 'Lab Homes' located on the Pacific Northwest National Laboratory (PNNL) campus during the 2012 winter heating season. Improving the insulation and solar heat gain characteristics of a home's windows has the potential to significantly improve the home's building envelope and overall thermal performance by reducing heat loss (in the winter), and cooling loss and solar heat gain (in the summer) through the windows. A high quality installation and/or window retrofit will also minimize or reduce air leakage through the window cavity and thus also contribute to reduced heat loss in the winter and cooling loss in the summer. These improvements all contribute to decreasing overall annual home energy use. Occupant comfort (non-quantifiable) can also be increased by minimizing or eliminating the cold 'draft' (temperature) many residents experience at or near window surfaces that are at a noticeably lower temperature than the room air temperature. Lastly, although not measured in this experiment, highly insulating windows (triple-pane in this experiment) also have the potential to significantly reduce the noise transmittance through windows compared to standard double-pane windows. The metered data taken in the Lab Homes and data analysis presented here represent 70 days of data taken during the 2012 heating season. As such, the savings from highly insulating windows in the experimental home (Lab Home B) compared to the standard double-pane clear glass windows in the baseline home (Lab Home A) are only a portion of the energy savings expected from a year-long experiment that would include a cooling season. The cooling season experiment will take place in the homes in the summer of 2012, and results of that experiment will be reported in a subsequent report available to all stakeholders.

High carbon losses due to recent cropland expansion in the United States

Science.gov (United States)

Spawn, S.; Lark, T.; Gibbs, H.

2017-12-01

Land conversion for agriculture in the United States has reached record highs in recent years. From 2008 to 2012 nearly 30,000 square kilometers of previously un-cultivated land were converted to agricultural land use with much of this expansion occurring on grasslands (77%) and shrublands (8%). To understand the effects of this conversion on global C cycling, we created novel, spatially explicit biomass maps for these biomes by combining existing satellite data products with models derived from field measurements. We then estimated changes in existing C stocks by combining our derived data with existing Landsat-scale data on land cover, land conversion, forest biomass and soil organic carbon (C) stocks. We find that conversion results in annual C losses of approximately 25 Tg C from US terrestrial ecosystems. Nationwide, roughly 80% of total emissions result from committed soil organic C losses. While biomass losses from expansion into forests and wetlands are disproportionately high per unit area, the vast majority of C losses occurred in grassland ecosystems, with grassland roots representing close to 70% of total biomass losses across all biomes. C losses are partially offset each year by agricultural abandonment which we estimate could sequester as much as 15 Tg C, annually. Taken together, we find that US agricultural expansion results in net annual emissions of 10 Tg C which is nearly 30% of emissions from existing US croplands. Our estimate is comparable to a recent analogous estimate for conversion of the Brazilian Cerrado and is equivalent to 10% of annual C losses from pantropical deforestation, suggesting that the effects of US cropland expansion could be globally significant.

[Morphophysiological and Behavioral Adaptations of Elk to Wintering].

Science.gov (United States)

Glushkov, V M; Kuznetsov, G V

2015-01-01

This paper studies morphometric parameters (body weight, weight of internal organs, body size, etc.) in 170 elk of various sex and age obtained in the Vyatka taiga area in winter. A number of physiological parameters (specific metabolism and thermal conductivity, heat loss rate, etc.) characterizing the metabolic rate and energy balance in the body were calculated for model animals (calf, male, and female). It is noted that in the transition from the first to the second half of winter the specific metabolism in model animals decreased from 20.6, 16.9, and 15.9 to 18.7, 15.4, and 14.5 kcal/(kg day), respectively. It is shown that changes in the rhythm of motor activity of elk are synchronized with the daily air temperature and the maximum flight distance depends on the amount of energy received by the body with food.

NUTRITION AS POSSIBLE ETHIOLOGICAL AGENT OF WINTER DISEASE SYNDROME IN SEA BREAM (Sparus aurata L.

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Gordana Šarušić

2000-12-01

Full Text Available The circumstance of winter disease phenomenon in intensively reared sea bream (Sparus aurata L. has been described. It’s occurence in Mediterranean has been registered and reported by several authors. The aim of this paper is to contribute to the comprehension on the aethiology of this syndrome which is causing significant losses in one year old cultured fish. Different types of commercial diets were introduced during 1994/95 rearing season to the sea bream reared in floating cages. The feeds were displaying differences in energetic compound level and vitamin A, D3 and E content. Health difficulties and mortality in the observed fish groups at the beginning of the problem, did not indicate any biotic agent as being responsible for such condition. Clinical features and mortality in the groups affected by winter disease syndrome were increasing by low sea temperature and correlating with feeding period by food containing low levels of protein, lipids and vitamins. Pathological findings were in particularly related to the organs involved in digestion. Growth rate was characteristic for the group that were suffering winter disease, where increasing in length was not followed by body weight. Clinical signs, simptomathology related to the organs involved in digestion, liver histology analyses, weight losses and pattern of weight and length relation, correlation between used feeds and occurrence of winter disease, implicated nutrition as one of most possible ethiological agent of this condition. Nutritional interventions applied contributed in comprehension of the winter disease syndrome. The relationship between nutritional requirements, particularly regerding autumn-winter period, has been researched and analyzed. The results approved our basic hypothesis.

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)

Winter is losing its cool

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Feng, S.

2017-12-01

Winter seasons have significant societal impacts across all sectors ranging from direct human health to ecosystems, transportation, and recreation. This study quantifies the severity of winter and its spatial-temporal variations using a newly developed winter severity index and daily temperature, snowfall and snow depth. The winter severity and the number of extreme winter days are decreasing across the global terrestrial areas during 1901-2015 except the southeast United States and isolated regions in the Southern Hemisphere. These changes are dominated by winter warming, while the changes in daily snowfall and snow depth played a secondary role. The simulations of multiple CMIP5 climate models can well capture the spatial and temporal variations of the observed changes in winter severity and extremes during 1951-2005. The models are consistent in projecting a future milder winter under various scenarios. The winter severity is projected to decrease 60-80% in the middle-latitude Northern Hemisphere under the business-as-usual scenario. The winter arrives later, ends earlier and the length of winter season will be notably shorter. The changes in harsh winter in the polar regions are weak, mainly because the warming leads to more snowfall in the high latitudes.

Estimating annual soil carbon loss in agricultural peatland soils using a nitrogen budget approach.

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Kirk, Emilie R; van Kessel, Chris; Horwath, William R; Linquist, Bruce A

2015-01-01

Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Oryza sativa) production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 - 4 % combined). Shallow groundwater contributed 24 - 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 - 81 % of plant N uptake (129 - 149 kg N ha-1) was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 - 70 %, estimated net C loss ranged from 1149 - 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices.

Elevated moisture stimulates carbon loss from mineral soils by releasing protected organic matter.

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Huang, Wenjuan; Hall, Steven J

2017-11-24

Moisture response functions for soil microbial carbon (C) mineralization remain a critical uncertainty for predicting ecosystem-climate feedbacks. Theory and models posit that C mineralization declines under elevated moisture and associated anaerobic conditions, leading to soil C accumulation. Yet, iron (Fe) reduction potentially releases protected C, providing an under-appreciated mechanism for C destabilization under elevated moisture. Here we incubate Mollisols from ecosystems under C 3 /C 4 plant rotations at moisture levels at and above field capacity over 5 months. Increased moisture and anaerobiosis initially suppress soil C mineralization, consistent with theory. However, after 25 days, elevated moisture stimulates cumulative gaseous C-loss as CO 2 and CH 4 to >150% of the control. Stable C isotopes show that mineralization of older C 3 -derived C released following Fe reduction dominates C losses. Counter to theory, elevated moisture may significantly accelerate C losses from mineral soils over weeks to months-a critical mechanistic deficiency of current Earth system models.

Wintering the common viper (Vipera berus with embryos

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Korosov Andrey Victorovich

2012-03-01

Full Text Available For the Vipers from Karelia phenomenon wintering females with embryos and the annual breeding were found. They were very large and heavy females (L.t. > 62 cm, W > 160 g, for which the mass loss due to pregnancy are not significant. Analysis of the size of 1450 individuals in a Kizhi population of viper showed that the proportion of females that can hibernate from embryos amounts to less than 3%.

Taphonomic trade-offs in tropical marine death assemblages: Differential time averaging, shell loss, and probable bias in siliciclastic vs. carbonate facies

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Kidwell, Susan M.; Best, Mairi M. R.; Kaufman, Darrell S.

2005-09-01

Radiocarbon-calibrated amino-acid racemization ages of individually dated bivalve mollusk shells from Caribbean reef, nonreefal carbonate, and siliciclastic sediments in Panama indicate that siliciclastic sands and muds contain significantly older shells (median 375 yr, range up to ˜5400 yr) than nearby carbonate seafloors (median 72 yr, range up to ˜2900 yr; maximum shell ages differ significantly at p < 0.02 using extreme-value statistics). The implied difference in shell loss rates is contrary to physicochemical expectations but is consistent with observed differences in shell condition (greater bioerosion and dissolution in carbonates). Higher rates of shell loss in carbonate sediments should lead to greater compositional bias in surviving skeletal material, resulting in taphonomic trade-offs: less time averaging but probably higher taxonomic bias in pure carbonate sediments, and lower bias but greater time averaging in siliciclastic sediments from humid-weathered accretionary arc terrains, which are a widespread setting of tropical sedimentation.

Black carbon measurements during winter 2013-2014 in Athens and intercomparison between different techniques

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Liakakou, Eleni; Stravroulas, Jason; Roukounakis, Nikolaos; Paraskevopoulou, Despina; Fourtziou, Luciana; Psiloglou, Vassilis; Gerasopoulos, Evangelos; Sciare, Jean; Mihalopoulos, Nikolaos

2014-05-01

Black carbon (BC) is a particulate pollutant species emitted from the combustion of fuels, biomass burning for agricultural purposes and forest fires, with the first two anthropogenic sources being the major contributors to the atmospheric burden of BC. The presence of BC is important due to its direct and indirect physicochemical effects and its use as a tracer of burning and subsequent transport processes. Black carbon measurements took place during winter 2013 -2014 in the frame of a pollution monitoring experiment conducted at the urban site of Thissio, Athens (city center) at the premises of the National Observatory of Athens. The economic crisis in Greece and the resulting turn of Athens inhabitants to wood burning for domestic heating, has led to increased daily concentrations of BC in the range of 2-6 μg m-3, peaking at night time (15-20 μg m-3). Three different optical methods were used for the determination of BC. A Particle Soot Absorption Photometer (PSAP; Radiance Research) commercial instrument was used to monitor the light absorption coefficient (σap) at 565 nm of ambient aerosols, with 1 minute resolution. During parts of the campaign, a portable Aethalometer (AE-42; Magee Scientific) was also used to provide measurement of the aerosol BC content at 7 wavelengths over 5 minutes intervals. Exploiting the measurements at different wavelengths is was feasible to separate wood burning BC from BC related to fossil fuel. Two Multi Angle Absorption Photometers (MAAP; Thermo) were also operated as reference. Finally, aerosol samples were collected on 12-hour basis using a sequential dichotomous sampler for the sampling of PM2.5, PM2.5-10and PM10 fractions of aerosols on quartz filters, and the filters were analyzed for elemental carbon (EC) by a thermal - optical transmission technique. The main objective of the study is the intercomparison of the different BC monitoring techniques under a large range of ambient concentrations achieved due to the special

Climate change affects winter chill for temperate fruit and nut trees.

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Luedeling, Eike; Girvetz, Evan H; Semenov, Mikhail A; Brown, Patrick H

2011-01-01

Temperate fruit and nut trees require adequate winter chill to produce economically viable yields. Global warming has the potential to reduce available winter chill and greatly impact crop yields. We estimated winter chill for two past (1975 and 2000) and 18 future scenarios (mid and end 21st century; 3 Global Climate Models [GCMs]; 3 greenhouse gas emissions [GHG] scenarios). For 4,293 weather stations around the world and GCM projections, Safe Winter Chill (SWC), the amount of winter chill that is exceeded in 90% of all years, was estimated for all scenarios using the "Dynamic Model" and interpolated globally. We found that SWC ranged between 0 and about 170 Chill Portions (CP) for all climate scenarios, but that the global distribution varied across scenarios. Warm regions are likely to experience severe reductions in available winter chill, potentially threatening production there. In contrast, SWC in most temperate growing regions is likely to remain relatively unchanged, and cold regions may even see an increase in SWC. Climate change impacts on SWC differed quantitatively among GCMs and GHG scenarios, with the highest GHG leading to losses up to 40 CP in warm regions, compared to 20 CP for the lowest GHG. The extent of projected changes in winter chill in many major growing regions of fruits and nuts indicates that growers of these commodities will likely experience problems in the future. Mitigation of climate change through reductions in greenhouse gas emissions can help reduce the impacts, however, adaption to changes will have to occur. To better prepare for likely impacts of climate change, efforts should be undertaken to breed tree cultivars for lower chilling requirements, to develop tools to cope with insufficient winter chill, and to better understand the temperature responses of tree crops.

Winter wheat response to irrigation, nitrogen fertilization, and cold hazards in the Community Land Model 5

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Lu, Y.

2017-12-01

Winter wheat is a staple crop for global food security, and is the dominant vegetation cover for a significant fraction of earth's croplands. As such, it plays an important role in soil carbon balance, and land-atmosphere interactions in these key regions. Accurate simulation of winter wheat growth is not only crucial for future yield prediction under changing climate, but also for understanding the energy and water cycles for winter wheat dominated regions. A winter wheat growth model has been developed in the Community Land Model 4.5 (CLM4.5), but its responses to irrigation and nitrogen fertilization have not been validated. In this study, I will validate winter wheat growth response to irrigation and nitrogen fertilization at five winter wheat field sites (TXLU, KSMA, NESA, NDMA, and ABLE) in North America, which were originally designed to understand winter wheat response to nitrogen fertilization and water treatments (4 nitrogen levels and 3 irrigation regimes). I also plan to further update the linkages between winter wheat yield and cold hazards. The previous cold damage function only indirectly affects yield through reduction on leaf area index (LAI) and hence photosynthesis, such approach could sometimes produce an unwanted higher yield when the reduced LAI saved more nutrient in the grain fill stage.

Diurnal Freeze-Thaw Cycles Modify Winter Soil Respiration in a Desert Shrub-Land Ecosystem

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Peng Liu

2016-07-01

Full Text Available Winter soil respiration (Rs is becoming a significant component of annual carbon budgets with more warming in winter than summer. However, little is known about the controlling mechanisms of winter Rs in dryland. We made continuous measurements of Rs in four microsites (non-crust (BS, lichen (LC, moss (MC, and a mixture of moss and lichen (ML in a desert shrub-land ecosystem northern China, to investigate the causes of Rs dynamics in winter. The mean winter Rs ranged from 0.10 to 0.17 µmol CO2 m−2·s−1 across microsites, with the highest value in BS. Winter Q10 (known as the increase in respiration rate per 10 °C increase in temperature values (2.8–19 were much higher than those from the growing season (1.5. Rs and Q10 were greatly enhanced in freeze-thaw cycles compared to frozen days. Diurnal patterns of Rs between freeze-thaw and frozen days differed. Although the freeze-thaw period was relatively short, its cumulative Rs contributed significantly to winter Rs. The presence of biocrust might induce lower temperature, thus having fewer freeze-thaw cycles relative to bare soil, leading to the lower Rs for microsites with biocrusts. In conclusion, winter Rs in drylands was sensitive to soil temperature (Ts and Ts-induced freeze-thaw cycles. The temperature impact on Rs varied among soil cover types. Winter Rs in drylands may become more important as the climate is continuously getting warmer.

Energy loss of argon in a laser-generated carbon plasma.

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Frank, A; Blazević, A; Grande, P L; Harres, K; Hessling, T; Hoffmann, D H H; Knobloch-Maas, R; Kuznetsov, P G; Nürnberg, F; Pelka, A; Schaumann, G; Schiwietz, G; Schökel, A; Schollmeier, M; Schumacher, D; Schütrumpf, J; Vatulin, V V; Vinokurov, O A; Roth, M

2010-02-01

The experimental data presented in this paper address the energy loss determination for argon at 4 MeV/u projectile energy in laser-generated carbon plasma covering a huge parameter range in density and temperature. Furthermore, a consistent theoretical description of the projectile charge state evolution via a Monte Carlo code is combined with an improved version of the CasP code that allows us to calculate the contributions to the stopping power of bound and free electrons for each projectile charge state. This approach gets rid of any effective charge description of the stopping power. Comparison of experimental data and theoretical results allows us to judge the influence of different plasma parameters.

Evaluation of seasonality on total water intake, water loss and water balance in the general population in Greece.

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Malisova, O; Bountziouka, V; Panagiotakos, D Β; Zampelas, A; Kapsokefalou, M

2013-07-01

Water balance is achieved when water intake from solid and fluid foods and drinking water meets water losses, mainly in sweat, urine and faeces. Seasonality, particularly in Mediterranean countries that have a hot summer, may affect water loss and consequently water balance. Water balance has not been estimated before on a population level and the effect of seasonality has not been evaluated. The present study aimed to compare water balance, intake and loss in summer and winter in a sample of the general population in Greece. The Water Balance Questionnaire (WBQ) was used to evaluate water balance, estimating water intake and loss in summer (n = 480) and in winter (n = 412) on a stratified sample of the general population in Athens, Greece. In winter, mean (SD) water balance was -63 (1478) mL/day(-1) , mean (SD)water intake was 2892 (987) mL/day(-1) and mean (quartile range) water loss was 2637 (1810-3922) mL/day(-1) . In summer, mean (SD) water balance was -58 (2150) mL/day(-1) , mean (SD) water intake was 3875 (1373) mL/day(-1) and mean (quartile range) water loss was 3635 (2365-5258) mL/day(-1) . Water balance did not differ between summer and winter (P = 0.96); however, the data distribution was different; in summer, approximately 8% more participants were falling in the low and high water balance categories. Differences in water intake from different sources were identified (P balance in summer and winter was not different. However, water intake and loss were approximately 40% higher in summer than in winter. More people were falling in the low and high water balance categories in summer when comparing the distribution on water balance in winter. © 2013 The Authors Journal of Human Nutrition and Dietetics © 2013 The British Dietetic Association Ltd.

Increasing carbon availability stimulates growth and secondary metabolites via modulation of phytohormones in winter wheat

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Reichelt, Michael; Chowdhury, Somak; Hammerbacher, Almuth; Hartmann, Henrik

2017-01-01

Abstract Phytohormones play important roles in plant acclimation to changes in environmental conditions. However, their role in whole-plant regulation of growth and secondary metabolite production under increasing atmospheric CO2 concentrations ([CO2]) is uncertain but crucially important for understanding plant responses to abiotic stresses. We grew winter wheat (Triticum aestivum) under three [CO2] (170, 390, and 680 ppm) over 10 weeks, and measured gas exchange, relative growth rate (RGR), soluble sugars, secondary metabolites, and phytohormones including abscisic acid (ABA), auxin (IAA), jasmonic acid (JA), and salicylic acid (SA) at the whole-plant level. Our results show that, at the whole-plant level, RGR positively correlated with IAA but not ABA, and secondary metabolites positively correlated with JA and JA-Ile but not SA. Moreover, soluble sugars positively correlated with IAA and JA but not ABA and SA. We conclude that increasing carbon availability stimulates growth and production of secondary metabolites via up-regulation of auxin and jasmonate levels, probably in response to sugar-mediated signalling. Future low [CO2] studies should address the role of reactive oxygen species (ROS) in leaf ABA and SA biosynthesis, and at the transcriptional level should focus on biosynthetic and, in particular, on responsive genes involved in [CO2]-induced hormonal signalling pathways. PMID:28159987

New winter hardy winter bread wheat cultivar (Triticum aestivum L. Voloshkova

Directory of Open Access Journals (Sweden)

Л. М. Голик

2007-12-01

Full Text Available Creation of Initial raw for breeding of winter wheat by change of the development type under low temperatures influence was described. Seeds of spring wheat were vernalized in aluminum weighting bottle. By using low temperatures at sawing of M2-6 at the begin ind of optimal terms of sawing of winter wheat, new winter-hardy variety of Voloshkova was bred.

Arctic sea ice, Eurasia snow, and extreme winter haze in China.

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Zou, Yufei; Wang, Yuhang; Zhang, Yuzhong; Koo, Ja-Ho

2017-03-01

The East China Plains (ECP) region experienced the worst haze pollution on record for January in 2013. We show that the unprecedented haze event is due to the extremely poor ventilation conditions, which had not been seen in the preceding three decades. Statistical analysis suggests that the extremely poor ventilation conditions are linked to Arctic sea ice loss in the preceding autumn and extensive boreal snowfall in the earlier winter. We identify the regional circulation mode that leads to extremely poor ventilation over the ECP region. Climate model simulations indicate that boreal cryospheric forcing enhances the regional circulation mode of poor ventilation in the ECP region and provides conducive conditions for extreme haze such as that of 2013. Consequently, extreme haze events in winter will likely occur at a higher frequency in China as a result of the changing boreal cryosphere, posing difficult challenges for winter haze mitigation but providing a strong incentive for greenhouse gas emission reduction.

33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.

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2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Winter Harbor Lobster Boat Race, Winter Harbor, ME. 100.109 Section 100.109 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.109 Winter Harbor...

State factor relationships of dissolved organic carbon and nitrogen losses from unpolluted temperate forest watersheds

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Perakis, S.S.; Hedin, L.O.

2007-01-01

We sampled 100 unpolluted, old-growth forested watersheds, divided among 13 separate study areas over 5 years in temperate southern Chile and Argentina, to evaluate relationships among dominant soil-forming state factors and dissolved carbon and nitrogen concentrations in watershed streams. These watersheds provide a unique opportunity to examine broad-scale controls over carbon (C) and nitrogen (N) biogeochemistry in the absence of significant human disturbance from chronic N deposition and land use change. Variations in the ratio dissolved organic carbon (DOC) to nitrogen (DON) in watershed streams differed by underlying soil parent material, with average C:N = 29 for watersheds underlain by volcanic ash and basalt versus C:N = 73 for sedimentary and metamorphic parent materials, consistent with stronger adsorption of low C:N hydrophobic materials by amorphous clays commonly associated with volcanic ash and basalt weathering. Mean annual precipitation was related positively to variations in both DOC (range: 0.2-9.7 mg C/L) and DON (range: 0.008-0.135 mg N/L) across study areas, suggesting that variations in water volume and concentration may act synergistically to influence C and N losses across dry to wet gradients in these forest ecosystems. Dominance of vegetation by broadleaf versus coniferous trees had negligible effects on organic C and N concentrations in comparison to abiotic factors. We conclude that precipitation volume and soil parent material are important controls over chemical losses of dissolved organic C and N from unpolluted temperate forest watersheds. Our results raise the possibility that biotic imprints on watershed C and N losses may be less pronounced in naturally N-poor forests than in areas impacted by land use change and chronic N deposition. Copyright 2007 by the American Geophysical Union.

Study of black carbon levels in city centers and industrial centers in Jordan

International Nuclear Information System (INIS)

Hamasha, K.M.; Almomani, M.S.; Abu-Allaban, M.; Arnott, W. P.

2010-01-01

Light absorption coefficients of black carbon (B abc ) were measured at serveral urban and industrial locations in Jordan during summer of 2007 and winter of 2008 using the photoacoustic instrument at a wavelength of 870 nm. Black carbon mass concentration (BC) was calculated using B abc .Black carbon levels at urban locations in the summer of 2007 were higher than those obtained at industrial centers.Zarqa had the highest value of BC in summer (29.24μg/m 3 ) and in winter (13.27μg/m 3 ). Ibbeen and Irbid city center had relatively high values of BC in winter: 11.75μg/m 3 and 12.48μg/m 3 , respectively. (authors).

Ozone Induced Premature Mortality and Crop Yield Loss in China

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Lin, Y.; Jiang, F.; Wang, H.

2017-12-01

Exposure to ambient ozone is a major risk factor for health impacts such as chronic obstructive pulmonary disease (COPD) and cause damage to plant and agricultural crops. But these impacts were usually evaluated separately in earlier studies. We apply Community Multi-scale Air Quality model to simulate the ambient O3 concentration at a resolution of 36 km×36 km across China. Then, we follow Global Burden of Diseases approach and AOT40 (i.e., above a threshold of 40 ppb) metric to estimate the premature mortalities and yield losses of major grain crops (i.e., winter wheat, rice and corn) across China due to surface ozone exposure, respectively. Our results show that ozone exposure leads to nearly 67,700 premature mortalities and 145 billion USD losses in 2014. The ozone induced yield losses of all crop production totaled 78 (49.9-112.6)million metric tons, worth 5.3 (3.4-7.6)billion USD, in China. The relative yield losses ranged from 8.5-14% for winter wheat, 3.9-15% for rice, and 2.2-5.5% for maize. We can see that the top four health affected provinces (Sichuan, Henan, Shandong, Jiangsu) are also ranking on the winter wheat and rice crop yield loss. Our results provide further evidence that surface ozone pollution is becoming urgent air pollution in China, and have important policy implications for China to alleviate the impacts of air pollution.

Estimating annual soil carbon loss in agricultural peatland soils using a nitrogen budget approach.

Directory of Open Access Journals (Sweden)

Emilie R Kirk

Full Text Available Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM oxidation and physical compaction. Rice (Oryza sativa production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 - 4 % combined. Shallow groundwater contributed 24 - 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 - 81 % of plant N uptake (129 - 149 kg N ha-1 was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 - 70 %, estimated net C loss ranged from 1149 - 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices.

Subsurface cadmium loss from a stony soil-effect of cow urine application.

Science.gov (United States)

Gray, Colin William; Chrystal, Jane Marie; Monaghan, Ross Martin; Cavanagh, Jo-Anne

2017-05-01

Cadmium (Cd) losses in subsurface flow from stony soils that have received cow urine are potentially important, but poorly understood. This study investigated Cd loss from a soil under a winter dairy-grazed forage crop that was grazed either conventionally (24 h) or with restricted grazing (6 h). This provided an opportunity to test the hypothesis that urine inputs could increase Cd concentrations in drainage. It was thought this would be a result of cow urine either (i) enhancing dissolved organic carbon (DOC) concentrations via an increase in soil pH, resulting in the formation of soluble Cd-organic carbon complexes and, or (ii) greater inputs of chloride (Cl) via cow urine, promoting the formation of soluble Cd-Cl complexes. Cadmium concentrations in subsurface flow were generally low, with a spike above the water quality guidelines for a month after the 24-h grazing. Cadmium fluxes were on average 0.30 g Cd ha -1  year -1 (0.27-0.32 g Cd ha -1  year -1 ), in line with previous estimates for agricultural soils. The mean Cd concentration in drainage from the 24-h grazed plots was significantly higher (P soil. Further study is warranted to confirm the mechanisms involved and quantities of Cd lost from other systems.

Effect of winter cold duration on spring phenology of the orange tip butterfly, Anthocharis cardamines.

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Stålhandske, Sandra; Lehmann, Philipp; Pruisscher, Peter; Leimar, Olof

2015-12-01

The effect of spring temperature on spring phenology is well understood in a wide range of taxa. However, studies on how winter conditions may affect spring phenology are underrepresented. Previous work on Anthocharis cardamines (orange tip butterfly) has shown population-specific reaction norms of spring development in relation to spring temperature and a speeding up of post-winter development with longer winter durations. In this experiment, we examined the effects of a greater and ecologically relevant range of winter durations on post-winter pupal development of A. cardamines of two populations from the United Kingdom and two from Sweden. By analyzing pupal weight loss and metabolic rate, we were able to separate the overall post-winter pupal development into diapause duration and post-diapause development. We found differences in the duration of cold needed to break diapause among populations, with the southern UK population requiring a shorter duration than the other populations. We also found that the overall post-winter pupal development time, following removal from winter cold, was negatively related to cold duration, through a combined effect of cold duration on diapause duration and on post-diapause development time. Longer cold durations also lead to higher population synchrony in hatching. For current winter durations in the field, the A. cardamines population of southern UK could have a reduced development rate and lower synchrony in emergence because of short winters. With future climate change, this might become an issue also for other populations. Differences in winter conditions in the field among these four populations are large enough to have driven local adaptation of characteristics controlling spring phenology in response to winter duration. The observed phenology of these populations depends on a combination of winter and spring temperatures; thus, both must be taken into account for accurate predictions of phenology.

Author Correction: Global patterns in mangrove soil carbon stocks and losses

Science.gov (United States)

Atwood, Trisha B.; Connolly, Rod M.; Almahasheer, Hanan; Carnell, Paul E.; Duarte, Carlos M.; Lewis, Carolyn J. Ewers; Irigoien, Xabier; Kelleway, Jeffrey J.; Lavery, Paul S.; Macreadie, Peter I.; Serrano, Oscar; Sanders, Christian J.; Santos, Isaac; Steven, Andrew D. L.; Lovelock, Catherine E.

2018-03-01

In the version of this Article originally published, the potential carbon loss from soils as a result of mangrove deforestation was incorrectly given as `2.0-75 Tg C yr-1'; this should have read `2-8 Tg C yr-1'. The corresponding emissions were incorrectly given as ` 7.3-275 Tg of CO2e'; this should have read ` 7-29 Tg of CO2e'. The corresponding percentage equivalent of these emissions compared with those from global terrestrial deforestation was incorrectly given as `0.2-6%'; this should have read `0.6-2.4%'. These errors have now been corrected in all versions of the Article.

Effects of biochar addition to soil on nitrogen fluxes in a winter wheat lysimeter experiment

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Hüppi, Roman; Leifeld, Jens; Neftel, Albrecht; Conen, Franz; Six, Johan

2014-05-01

Biochar is a carbon-rich, porous residue from pyrolysis of biomass that potentially increases crop yields by reducing losses of nitrogen from soils and/or enhancing the uptake of applied fertiliser by the crops. Previous research is scarce about biochar's ability to increase wheat yields in temperate soils or how it changes nitrogen dynamics in the field. In a lysimeter system with two different soils (sandy/silt loam) nitrogen fluxes were traced by isotopic 15N enriched fertiliser to identify changes in nitrous oxide emissions, leaching and plant uptake after biochar addition. 20t/ha woodchip-waste biochar (pH=13) was applied to these soils in four lysimeters per soil type; the same number of lysimeters served as a control. The soils were cropped with winter wheat during the season 2012/2013. 170 kg-N/ha ammonium nitrate fertiliser with 10% 15N was applied in 3 events during the growing season and 15N concentrations where measured at different points in time in plant, soil, leachate and emitted nitrous oxide. After one year the lysimeter system showed no difference between biochar and control treatment in grain- and straw yield or nitrogen uptake. However biochar did reduce nitrous oxide emissions in the silt loam and losses of nitrate leaching in sandy loam. This study indicates potential reduction of nitrogen loss from cropland soil by biochar application but could not confirm increased yields in an intensive wheat production system.

A Possible Link Between Winter Arctic Sea Ice Decline and a Collapse of the Beaufort High?

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Petty, Alek A.

2018-03-01

A new study by Moore et al. (2018, https://doi.org/10.1002/2017GL076446) highlights a collapse of the anticyclonic "Beaufort High" atmospheric circulation over the western Arctic Ocean in the winter of 2017 and an associated reversal of the sea ice drift through the southern Beaufort Sea (eastward instead of the predominantly westward circulation). The authors linked this to the loss of sea ice in the Barents Sea, anomalous warming over the region, and the intrusion of low-pressure cyclones along the eastern Arctic. In this commentary we discuss the significance of this observation, the challenges associated with understanding these possible linkages, and some of the alternative hypotheses surrounding the impacts of winter Arctic sea ice loss.

Impact of land use change on soil carbon loss of the Sikkim Himalayan piedmont

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Prokop, Pawel; Ploskonka, Dominik

2014-05-01

Natural and human causes of change in land use on soil carbon were studied at the outlet of the Tista River from the Sikkim Himalayas over the last 150 years. Analysis of topographic maps and satellite images indicates that the land reforms related to location of tea gardens in the piedmont caused rapid deforestation of terraces in the late 19th century. Continuous population growth after 1930 initiated the replacement of floodplain forest by rice cultivation. Both processes changed soil carbon content and intensified fluvial activity expressed through terrace erosion. The replacement of natural forest by tea cultivation reduced the soil carbon content within terraces from 1.95 kg to 1.77 kg (in 1 m of topsoil) respectively. The replacement of natural forest by rice reduced the soil carbon content within floodplains from 0.42 kg to 0.23 kg (in 1 m topsoil) respectively. Much more dangerous, was terrace erosion leading to permanent removal of sediment including soil. The total loss of soil carbon in a 1 m thick soil layer due to conversion of 5 km2 forest to tea cultivation was about 900 t between 1930 and 2010. While the total soil carbon removed due to 1.8 km2 terrace erosion reached 3510 t in the same period. Result is the outcome of research project 2012/05/B/ST10/00309 of the National Science Centre (Poland).

Influence of age and sex on winter site fidelity of sanderlings Calidris alba

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Pedro M. Lourenço

2016-09-01

Full Text Available Many migratory bird species show high levels of site fidelity to their wintering sites, which confers advantages due to prior knowledge, but may also limit the ability of the individual to move away from degrading sites or to detect alternative foraging opportunities. Winter site fidelity often varies among age groups, but sexual differences have seldom been recorded in birds. We studied a population of individually colour-marked sanderlings wintering in and around the Tejo estuary, a large estuarine wetland on the western coast of Portugal. For 160 individuals, sighted a total of 1,249 times between November 2009 and March 2013, we calculated the probability that they moved among five distinct wintering sites and how this probability is affected by distance between them. To compare site fidelity among age classes and sexes, as well as within the same winter and over multiple winters, we used a Site Fidelity Index (SFI. Birds were sexed using a discriminant function based on biometrics of a large set of molecularly sexed sanderlings (n = 990. The vast majority of birds were observed at one site only, and the probability of the few detected movements between sites was negatively correlated with the distance among each pair of sites. Hardly any movements were recorded over more than 15 km, suggesting small home ranges. SFI values indicated that juveniles were less site-faithful than adults which may reflect the accumulated knowledge and/or dominance of older animals. Among adults, females were significantly less site faithful than males. A sexual difference in winter site fidelity is unusual in shorebirds. SFI values show site-faithfulness is lower when multiple winters were considered, and most birds seem to chose a wintering site early in the season and use that site throughout the winter. Sanderlings show a very limited tendency to explore alternative wintering options, which might have implications for their survival when facing habitat change

A trajectory analysis of atmospheric transport of black carbon aerosols to Canadian high Arctic in winter and spring (1990–2005

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L. Huang

2010-06-01

Full Text Available Black carbon (BC particles accumulated in the Arctic troposphere and deposited on snow have been calculated to have significant effects on radiative forcing of the Arctic regional climate. Applying cluster analysis technique on 10-day backward trajectories, seven distinct transport pathways (or clusters affecting Alert (82.5° N, 62.5° W, Nunavut in Canada are identified in this work. Transport frequency associated with each pathway is obtained as the fraction of trajectories in that cluster. Based on atmospheric transport frequency and BC surface flux from surrounding regions (i.e. North America, Europe, and former USSR, a linear regression model is constructed to investigate the inter-annual variations of BC observed at Alert in January and April, representative of winter and spring respectively, between 1990 and 2005. Strong correlations are found between BC concentrations predicted with the regression model and measurements at Alert for both seasons (R² equals 0.77 and 0.81 for winter and spring, respectively. Results imply that atmospheric transport and BC emission are the major contributors to the inter-annual variations in BC concentrations observed at Alert in the cold seasons for the 16-year period. Other factors, such as deposition, could also contribute to the variability in BC concentrations but were not considered in this analysis. Based on the regression model the relative contributions of regional BC emissions affecting Alert are attributed to the Eurasian sector, composed of the European Union and the former USSR, and the North American sector. Considering both seasons, the model suggests that former USSR is the major contributor to the near-surface BC levels at the Canadian high Arctic site with an average contribution of about 67% during the 16-year period, followed by European Union (18% and North America (15%. In winter, the atmospheric transport of BC aerosols from Eurasia is found to be even more

Derivation of Hamaker Dispersion Energy of Amorphous Carbon Surfaces in Contact with Liquids Using Photoelectron Energy-Loss Spectra

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Godet, Christian; David, Denis

2017-12-01

Hamaker interaction energies and cutoff distances have been calculated for disordered carbon films, in contact with purely dispersive (diiodomethane) or polar (water) liquids, using their experimental dielectric functions ɛ ( q, ω) obtained over a broad energy range. In contrast with previous works, a q-averaged q is derived from photoelectron energy-loss spectroscopy (XPS-PEELS) where the energy loss function (ELF) q is a weighted average over allowed transferred wave vector values, q, given by the physics of bulk plasmon excitation. For microcrystalline diamond and amorphous carbon films with a wide range of (sp3/sp2 + sp3) hybridization, non-retarded Hamaker energies, A 132 ( L < 1 nm), were calculated in several configurations, and distance and wavenumber cutoff values were then calculated based on A 132 and the dispersive work of adhesion obtained from contact angles. A geometric average approximation, H 0 CVL = ( H 0 CVC H 0 LVL )1/2, holds for the cutoff separation distances obtained for carbon-vacuum-liquid (CVL), carbon-vacuum-carbon (CVC) and liquid-vacuum-liquid (LVL) equilibrium configurations. The linear dependence found for A CVL, A CLC and A CLV values as a function of A CVC, for each liquid, allows predictive relationships for Hamaker energies (in any configuration) using experimental determination of the dispersive component of the surface tension, {γ}_{CV}^d , and a guess value of the cutoff distance H 0 CVC of the solid. [Figure not available: see fulltext.

Winter ecology of a subalpine grassland: Effects of snow removal on soil respiration, microbial structure and function.

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Gavazov, Konstantin; Ingrisch, Johannes; Hasibeder, Roland; Mills, Robert T E; Buttler, Alexandre; Gleixner, Gerd; Pumpanen, Jukka; Bahn, Michael

2017-07-15

Seasonal snow cover provides essential insulation for mountain ecosystems, but expected changes in precipitation patterns and snow cover duration due to global warming can influence the activity of soil microbial communities. In turn, these changes have the potential to create new dynamics of soil organic matter cycling. To assess the effects of experimental snow removal and advanced spring conditions on soil carbon (C) and nitrogen (N) dynamics, and on the biomass and structure of soil microbial communities, we performed an in situ study in a subalpine grassland in the Austrian Alps, in conjunction with soil incubations under controlled conditions. We found substantial winter C-mineralisation and high accumulation of inorganic and organic N in the topsoil, peaking at snowmelt. Soil microbial biomass doubled under the snow, paralleled by a fivefold increase in its C:N ratio, but no apparent change in its bacteria-dominated community structure. Snow removal led to a series of mild freeze-thaw cycles, which had minor effects on in situ soil CO 2 production and N mineralisation. Incubated soil under advanced spring conditions, however, revealed an impaired microbial metabolism shortly after snow removal, characterised by a limited capacity for C-mineralisation of both fresh plant-derived substrates and existing soil organic matter (SOM), leading to reduced priming effects. This effect was transient and the observed recovery in microbial respiration and SOM priming towards the end of the winter season indicated microbial resilience to short-lived freeze-thaw disturbance under field conditions. Bacteria showed a higher potential for uptake of plant-derived C substrates during this recovery phase. The observed temporary loss in microbial C-mineralisation capacity and the promotion of bacteria over fungi can likely impede winter SOM cycling in mountain grasslands under recurrent winter climate change events, with plausible implications for soil nutrient availability and

Intensive ground vegetation growth mitigates the carbon loss after forest disturbance.

Science.gov (United States)

Zehetgruber, Bernhard; Kobler, Johannes; Dirnböck, Thomas; Jandl, Robert; Seidl, Rupert; Schindlbacher, Andreas

2017-01-01

Slow or failed tree regeneration after forest disturbance is increasingly observed in the central European Alps, potentially amplifying the carbon (C) loss from disturbance. We aimed at quantifying C dynamics of a poorly regenerating disturbance site with a special focus on the role of non-woody ground vegetation. Soil CO 2 efflux, fine root biomass, ground vegetation biomass, tree increment and litter input were assessed in (i) an undisturbed section of a ~ 110 years old Norway spruce stand, (ii) in a disturbed section which was clear-cut six years ago (no tree regeneration), and (iii) in a disturbed section which was clear-cut three years ago (no tree regeneration). Total soil CO 2 efflux was similar across all stand sections (8.5 ± 0.2 to 8.9 ± 0.3 t C ha -1  yr. -1 ). The undisturbed forest served as atmospheric C sink (2.1 t C ha -1  yr. -1 ), whereas both clearings were C sources to the atmosphere. The source strength three years after disturbance (-5.5 t C ha -1  yr. -1 ) was almost twice as high as six years after disturbance (-2.9 t C ha -1  yr. -1 ), with declining heterotrophic soil respiration and the high productivity of dense graminoid ground vegetation mitigating C loss. C loss after disturbance decreases with time and ground vegetation growth. Dense non-woody ground vegetation cover can hamper tree regeneration but simultaneously decrease the ecosystem C loss. The role of ground vegetation should be more explicitly taken into account in forest C budgets assessing disturbance effects.

Characterization of black carbon in the ambient air of Agra, India: Seasonal variation and meteorological influence

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Gupta, Pratima; Singh, Shalendra Pratap; Jangid, Ashok; Kumar, Ranjit

2017-09-01

This study characterizes the black carbon in Agra, India home to the Taj Mahal—and situated in the Indo-Gangetic basin. The mean black carbon concentration is 9.5 μg m-3 and, owing to excessive biomass/fossil fuel combustion and automobile emissions, the concentration varies considerably. Seasonally, the black carbon mass concentration is highest in winter, probably due to the increased fossil fuel consumption for heating and cooking, apart from a low boundary layer. The nocturnal peak rises prominently in winter, when the use of domestic heating is excessive. Meanwhile, the concentration is lowest during the monsoon season because of the turbulent atmospheric conditions and the process of washout by precipitation. The ratio of black carbon to brown carbon is less than unity during the entire study period, except in winter (December). This may be because that biomass combustion and diesel exhaust are major black carbon contributors in this region, while a higher ratio in winter may be due to the increased consumption of fossil fuel and wood for heating purposes. ANOVA reveals significant monthly variation in the concentration of black carbon; plus, it is negatively correlated with wind speed and temperature. A high black carbon mass concentration is observed at moderate (1-2 m s-1) wind speed, as compared to calm or turbulent atmospheric conditions.

Stochastic Modeling of Empirical Storm Loss in Germany

Science.gov (United States)

Prahl, B. F.; Rybski, D.; Kropp, J. P.; Burghoff, O.; Held, H.

2012-04-01

Based on German insurance loss data for residential property we derive storm damage functions that relate daily loss with maximum gust wind speed. Over a wide range of loss, steep power law relationships are found with spatially varying exponents ranging between approximately 8 and 12. Global correlations between parameters and socio-demographic data are employed to reduce the number of local parameters to 3. We apply a Monte Carlo approach to calculate German loss estimates including confidence bounds in daily and annual resolution. Our model reproduces the annual progression of winter storm losses and enables to estimate daily losses over a wide range of magnitude.

The extent and pathways of nitrogen loss in turfgrass systems: Age impacts.

Science.gov (United States)

Chen, Huaihai; Yang, Tianyou; Xia, Qing; Bowman, Daniel; Williams, David; Walker, John T; Shi, Wei

2018-05-11

Nitrogen loss from fertilized turf has been a concern for decades, with most research focused on inorganic (NO 3 - ) leaching. The present work examined both inorganic and organic N species in leachate and soil N 2 O emissions from intact soil cores of a bermudagrass chronosequence (1, 15, 20, and 109 years old) collected in both winter and summer. Measurements of soil N 2 O emissions were made daily for 3 weeks, while leachate was sampled once a week. Four treatments were established to examine the impacts of fertilization and temperature: no N, low N at 30 kg N ha -1 , and high N at 60 kg N ha -1 , plus a combination of high N and temperature (13 °C in winter or 33 °C in summer compared to the standard 23 °C). Total reactive N loss generally showed a "cup" pattern of turf age, being lowest for the 20 years old. Averaged across all intact soil cores sampled in winter and summer, organic N leaching accounted for 51% of total reactive N loss, followed by inorganic N leaching at 41% and N 2 O-N efflux at 8%. Proportional loss among the fractions varied with grass age, season, and temperature and fertilization treatments. While high temperature enhanced total reactive N loss, it had little influence on the partitioning of loss among dissolved organic N, inorganic N and N 2 O-N when C availability was expected to be high in summer due to rhizodeposition and root turnover. This effect of temperature was perhaps due to higher microbial turnover in response to increased C availability in summer. However when C availability was low in winter, warming might mainly affect microbial growth efficiency and therefore partitioning of N. This work provides a new insight into the interactive controls of warming and substrate availability on dissolved organic N loss from turfgrass systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Winter Weather Emergencies

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Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

Effects of Revegetation on Soil Organic Carbon Storage and Erosion-Induced Carbon Loss under Extreme Rainstorms in the Hill and Gully Region of the Loess Plateau.

Science.gov (United States)

Li, Yujin; Jiao, Juying; Wang, Zhijie; Cao, Binting; Wei, Yanhong; Hu, Shu

2016-04-29

The Loess Plateau, an ecologically vulnerable region, has long been suffering from serious soil erosion. Revegetation has been implemented to control soil erosion and improve ecosystems in the Loess Plateau region through a series of ecological recovery programs. However, the increasing atmospheric CO₂ as a result of human intervention is affecting the climate by global warming, resulting in the greater frequency and intensity of extreme weather events, such as storms that may weaken the effectiveness of revegetation and cause severe soil erosion. Most research to date has evaluated the effectiveness of revegetation on soil properties and soil erosion of different land use or vegetation types. Here, we study the effect of revegetation on soil organic carbon (SOC) storage and erosion-induced carbon loss related to different plant communities, particularly under extreme rainstorm events. The erosion-pin method was used to quantify soil erosion, and soil samples were taken at soil depths of 0-5 cm, 5-10 cm and 10-20 cm to determine the SOC content for 13 typical hillside revegetation communities in the year of 2013, which had the highest rainfall with broad range, long duration and high intensity since 1945, in the Yanhe watershed. The SOC concentrations of all plant communities increased with soil depth when compared with slope cropland, and significant increases (p soil loss and SOC loss were both 1.0), the relative soil loss and SOC loss of the other 12 plant communities in 2013 ranged from 1.5 to 9.4 and 0.30 to 1.73, respectively. Natural shrub and forest communities showed greater resistance to rainstorm erosion than grassland communities. The natural grassland communities with lower SOC content produced lower SOC loss even with higher soil loss, natural secondary forest communities produced higher SOC loss, primarily because of their higher SOC content, and the artificial R. pseudoacacia community with greater soil loss produced higher SOC loss. These results

Influences of the Landscape on Life Cycle Carbon Intensity of Biofuels

Science.gov (United States)

Adler, P. R.; Del Grosso, S.; Parton, W. J.; Spatari, S.

2011-12-01

Biofuels derived from first (sugar and starch based) and second (lignocellulosic) generation agricultural feedstocks will continue to expand into the market between now and 2022 as incentivized through the federal Energy Independence and Security Act (EISA). Nitrogen use is one of the key environmental concerns within the life cycle since it is both the dominant source of life cycle greenhouse gas (GHG) emissions (energy from N fertilizer production and N2O emissions) and poses risks of reactive N movement throughout agricultural landscapes and watersheds. The other dominant components of the feedstock production on life cycle GHG emissions are tillage and land use change impacts on soil organic carbon (SOC). Opportunities to reduce reactive N through winter double crops may satisfy the dual goal of mitigating N2O emissions and reducing NO3 loses while meeting the objectives of EISA. However, changes in N2O, NO3, and SOC are variable within the agricultural landscape due to soil texture, climate, and crop rotation history thereby increasing the complexity of developing mitigation recommendations. Moreover, the inherent variability in N2O emissions makes it difficult to develop single life cycle carbon intensity profiles for specific fuel pathways that apply across the US, since those pathways will have geographic dependencies. Estimating the expected changes in N2O and SOC is an integral part of quantifying the life cycle GHG profile of biofuels derived from winter double crop feedstocks, while NO3 losses affect both indirect N2O emissions and water quality. The biogeochemical model DayCent was used to simulate the impact of growing winter barley as a double crop following corn before soybean establishment during the winter fallow period for six states in the Mid Atlantic region of the Eastern US on SOC and direct and indirect N2O. EPA is currently reviewing the addition of an advanced fuel pathway for winter barley in the Mid Atlantic region as part of the RFS2

Icing losses on wind turbines

Energy Technology Data Exchange (ETDEWEB)

Duncan, T.; Fotsing, I.; Pearson, S. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

2010-07-01

This PowerPoint presentation discussed some of the energy losses that can occur as a result of icing on wind turbines. Airfoil deterioration can occur in the presence of rime and glaze ice. Anemometers are also impacted by ice, and shut-downs can occur as a result of icing events. Availability deficits that occur during the winter months can lead to annual energy losses of 0.5 percent. The impact of icing events on total wind power energy production in Quebec is estimated at between 1.3 percent to 2.7 percent. Ice loss estimates are considered during the pre-construction phases of wind power projects. However, ice loss prediction methods are often inaccurate. Studies have demonstrated that preconstruction masts show a reasonable correlation with wind turbine icing, and that icing losses are site-specific. tabs., figs.

Application of electron energy loss spectroscopy for single wall carbon nanotubes (review)

International Nuclear Information System (INIS)

Mittal, N.; Jain, S.; Mittal, J.

2015-01-01

Electron energy loss spectroscopy (EELS) is among the few techniques that are available for the characterization of modified single wall carbon nanotubes (SWCNTs) having nanometer dimensions (~1-3 nm). CNTs can be modified either by surface functionalization or coating, between bundles of nanotubes by doping, intercalation and fully or partially filling the central core. EELS is an exclusive technique for the identification, composition analysis, and crystallization studies of the chemicals and materials used for the modification of SWCNTs. The present paper serves as a compendium of research work on the application of EELS for the characterization of modified SWCNTs. (authors)

Hibernation in an antarctic fish: on ice for winter.

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Hamish A Campbell

Full Text Available Active metabolic suppression in anticipation of winter conditions has been demonstrated in species of mammals, birds, reptiles and amphibians, but not fish. This is because the reduction in metabolic rate in fish is directly proportional to the decrease in water temperature and they appear to be incapable of further suppressing their metabolic rate independently of temperature. However, the Antarctic fish (Notothenia coriiceps is unusual because it undergoes winter metabolic suppression irrespective of water temperature. We assessed the seasonal ecological strategy by monitoring swimming activity, growth, feeding and heart rate (f(H in N. coriiceps as they free-ranged within sub-zero waters. The metabolic rate of wild fish was extrapolated from f(H recordings, from oxygen consumption calibrations established in the laboratory prior to fish release. Throughout the summer months N. coriiceps spent a considerable proportion of its time foraging, resulting in a growth rate (G(w of 0.18 +/- 0.2% day(-1. In contrast, during winter much of the time was spent sedentary within a refuge and fish showed a net loss in G(w (-0.05 +/- 0.05% day(-1. Whilst inactive during winter, N. coriiceps displayed a very low f(H, reduced sensory and motor capabilities, and standard metabolic rate was one third lower than in summer. In a similar manner to other hibernating species, dormancy was interrupted with periodic arousals. These arousals, which lasted a few hours, occurred every 4-12 days. During arousal activity, f(H and metabolism increased to summer levels. This endogenous suppression and activation of metabolic processes, independent of body temperature, demonstrates that N. coriiceps were effectively 'putting themselves on ice' during winter months until food resources improved. This study demonstrates that at least some fish species can enter a dormant state similar to hibernation that is not temperature driven and presumably provides seasonal energetic

How Does Recycling of Livestock Manure in Agroecosystems Affect Crop Productivity, Reactive Nitrogen Losses, and Soil Carbon Balance?

Science.gov (United States)

Xia, Longlong; Lam, Shu Kee; Yan, Xiaoyuan; Chen, Deli

2017-07-05

Recycling of livestock manure in agroecosystems to partially substitute synthetic fertilizer nitrogen (N) input is recommended to alleviate the environmental degradation associated with synthetic N fertilization, which may also affect food security and soil greenhouse gas (GHG) emissions. However, how substituting livestock manure for synthetic N fertilizer affects crop productivity (crop yield; crop N uptake; N use efficiency), reactive N (Nr) losses (ammonia (NH 3 ) emission, N leaching and runoff), GHG (methane, CH 4 ; and nitrous oxide, N 2 O; carbon dioxide) emissions and soil organic carbon (SOC) sequestration in agroecosystems is not well understood. We conducted a global meta-analysis of 141 studies and found that substituting livestock manure for synthetic N fertilizer (with equivalent N rate) significantly increased crop yield by 4.4% and significantly decreased Nr losses via NH 3 emission by 26.8%, N leaching by 28.9% and N runoff by 26.2%. Moreover, annual SOC sequestration was significantly increased by 699.6 and 401.4 kg C ha -1 yr -1 in upland and paddy fields, respectively; CH 4 emission from paddy field was significantly increased by 41.2%, but no significant change of that was observed from upland field; N 2 O emission was not significantly affected by manure substitution in upland or paddy fields. In terms of net soil carbon balance, substituting manure for fertilizer increased carbon sink in upland field, but increased carbon source in paddy field. These results suggest that recycling of livestock manure in agroecosystems improves crop productivity, reduces Nr pollution and increases SOC storage. To attenuate the enhanced carbon source in paddy field, appropriate livestock manure management practices should be adopted.

Dynamics of sea-ice biogeochemistry in the coastal Antarctica during transition from summer to winter

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Suhas Shetye

2017-05-01

Full Text Available The seasonality of carbon dioxide partial pressure (pCO2, air-sea CO2 fluxes and associated environmental parameters were investigated in the Antarctic coastal waters. The in-situ survey was carried out from the austral summer till the onset of winter (January 2012, February 2010 and March 2009 in the Enderby Basin. Rapid decrease in pCO2 was evident under the sea-ice cover in January, when both water column and sea-ice algal activity resulted in the removal of nutrients and dissolved inorganic carbon (DIC and increase in pH. The major highlight of this study is the shift in the dominant biogeochemical factors from summer to early winter. Nutrient limitation (low Si/N, sea-ice cover, low photosynthetically active radiation (PAR, deep mixed layer and high upwelling velocity contributed towards higher pCO2 during March (early winter. CO2 fluxes suggest that the Enderby Basin acts as a strong CO2 sink during January (−81 mmol m−2 d−1, however it acts as a weak sink of CO2 with −2.4 and −1.7 mmol m−2 d−1 during February and March, respectively. The present work, concludes that sea ice plays a dual role towards climate change, by decreasing sea surface pCO2 in summer and enhancing in early winter. Our observations emphasize the need to address seasonal sea-ice driven CO2 flux dynamics in assessing Antarctic contributions to the global oceanic CO2 budget.

Limited dietary overlap amongst resident Arctic herbivores in winter: complementary insights from complementary methods.

Science.gov (United States)

Schmidt, Niels M; Mosbacher, Jesper B; Vesterinen, Eero J; Roslin, Tomas; Michelsen, Anders

2018-04-26

Snow may prevent Arctic herbivores from accessing their forage in winter, forcing them to aggregate in the few patches with limited snow. In High Arctic Greenland, Arctic hare and rock ptarmigan often forage in muskox feeding craters. We therefore hypothesized that due to limited availability of forage, the dietary niches of these resident herbivores overlap considerably, and that the overlap increases as winter progresses. To test this, we analyzed fecal samples collected in early and late winter. We used molecular analysis to identify the plant taxa consumed, and stable isotope ratios of carbon and nitrogen to quantify the dietary niche breadth and dietary overlap. The plant taxa found indicated only limited dietary differentiation between the herbivores. As expected, dietary niches exhibited a strong contraction from early to late winter, especially for rock ptarmigan. This may indicate increasing reliance on particular plant resources as winter progresses. In early winter, the diet of rock ptarmigan overlapped slightly with that of muskox and Arctic hare. Contrary to our expectations, no inter-specific dietary niche overlap was observed in late winter. This overall pattern was specifically revealed by combined analysis of molecular data and stable isotope contents. Hence, despite foraging in the same areas and generally feeding on the same plant taxa, the quantitative dietary overlap between the three herbivores was limited. This may be attributable to species-specific consumption rates of plant taxa. Yet, Arctic hare and rock ptarmigan may benefit from muskox opening up the snow pack, thereby allowing them to access the plants.

Cover cropping to reduce nitrate loss through subsurface drainage in the northern U.S. corn belt.

Science.gov (United States)

Strock, J S; Porter, P M; Russelle, M P

2004-01-01

Despite the use of best management practices for nitrogen (N) application rate and timing, significant losses of nitrate nitrogen (NO3(-)-N) in drainage discharge continue to occur from row crop cropping systems. Our objective was to determine whether a autumn-seeded winter rye (Secale cereale L.) cover crop following corn (Zea mays L.) would reduce NO3(-)-N losses through subsurface tile drainage in a corn-soybean [Glycine mar (L.) Merr.] cropping system in the northern Corn Belt (USA) in a moderately well-drained soil. Both phases of the corn-soybean rotation, with and without the winter rye cover crop following corn, were established in 1998 in a Normania clay loam (fine-loamy, mixed, mesic Aquic Haplustoll) soil at Lamberton, MN. Cover cropping did not affect subsequent soybean yield, but reduced drainage discharge, flow-weighted mean nitrate concentration (FWMNC), and NO3(-)-N loss relative to winter fallow, although the magnitude of the effect varied considerably with annual precipitation. Three-year average drainage discharge was lower with a winter rye cover crop than without (p = 0.06). Over three years, subsurface tile-drainage discharge was reduced 11% and NO3(-)-N loss was reduced 13% for a corn-soybean cropping system with a rye cover crop following corn than with no rye cover crop. We estimate that establishment of a winter rye cover crop after corn will be successful in one of four years in southwestern Minnesota. Cover cropping with rye has the potential to be an effective management tool for reducing NO3(-)-N loss from subsurface drainage discharge despite challenges to establishment and spring growth in the north-central USA.

Future changes in atmospheric rivers and their implications for winter flooding in Britain

International Nuclear Information System (INIS)

Lavers, David A; Allan, Richard P; Brayshaw, David J; Villarini, Gabriele; Lloyd-Hughes, Benjamin; Wade, Andrew J

2013-01-01

Within the warm conveyor belt of extra-tropical cyclones, atmospheric rivers (ARs) are the key synoptic features which deliver the majority of poleward water vapour transport, and are associated with episodes of heavy and prolonged rainfall. ARs are responsible for many of the largest winter floods in the mid-latitudes resulting in major socioeconomic losses; for example, the loss from United Kingdom (UK) flooding in summer/winter 2012 is estimated to be about $1.6 billion in damages. Given the well-established link between ARs and peak river flows for the present day, assessing how ARs could respond under future climate projections is of importance in gauging future impacts from flooding. We show that North Atlantic ARs are projected to become stronger and more numerous in the future scenarios of multiple simulations from five state-of-the-art global climate models (GCMs) in the fifth Climate Model Intercomparison Project (CMIP5). The increased water vapour transport in projected ARs implies a greater risk of higher rainfall totals and therefore larger winter floods in Britain, with increased AR frequency leading to more flood episodes. In the high emissions scenario (RCP8.5) for 2074–2099 there is an approximate doubling of AR frequency in the five GCMs. Our results suggest that the projected change in ARs is predominantly a thermodynamic response to warming resulting from anthropogenic radiative forcing. (letter)

Simulation of Wild oat (Avena ludoviciana L. Competition on Winter Wheat (Triticum astivum Growth and Yield. I: Model Description and Validation

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F Mondani

2015-09-01

Full Text Available Crop growth models could stimulate growth and development based on science principles and mathematical equations. They also able to evaluate effects of climate, soil, water and agronomic management practices on crop yield. In the present study, an eco-physiological simulation model developed to assess wild oat damage to winter wheat growth and yield. The general structure of this model is derived from LINTUL1 model which modified to wild oat competition against winter wheat. LINTUL1 model was developed for simulation of spring wheat potential production level. In this study, first, we added development stage (DVS and vernalization to LINTUL1 for simulation of winter wheat growth and development and then the model calibrated for potential production level. Finally, we incorporate harmful effects of wild oat to winter wheat growth and yield. Weather data used as input were average daily minimum and maximum temperature (°C and daily global radiation (MJ m-2 in Mashhad, Iran. Parameter values were derived from the literature. The model is written in Fortran Simulation Translator (FST programming language and then validated based on an experiment data. For these purposes different wild oat plant densities were arranged. The data of this experiment does not use for calibration. The results showed that this model was in general able to simulate the temporal changes in DVS of winter wheat and wild oat, total dry matter (TDM of winter wheat and wild oat and yield loss of wheat due to wild oat competition in all treatments, satisfactorily. Root mean square error (RMSE for winter wheat DVS, wild oat DVS, average winter wheat TDM, average wild oat TDM, and yield loss of winter wheat was 10.4, 14.5, 5.8, 7.6 and 7.5, respectively.

Global patterns in mangrove soil carbon stocks and losses

KAUST Repository

Atwood, Trisha B.

2017-06-26

Mangrove soils represent a large sink for otherwise rapidly recycled carbon (C). However, widespread deforestation threatens the preservation of this important C stock. It is therefore imperative that global patterns in mangrove soil C stocks and their susceptibility to remineralization are understood. Here, we present patterns in mangrove soil C stocks across hemispheres, latitudes, countries and mangrove community compositions, and estimate potential annual CO2 emissions for countries where mangroves occur. Global potential CO2 emissions from soils as a result of mangrove loss were estimated to be ~7.0 Tg CO2e yr−1. Countries with the highest potential CO2 emissions from soils are Indonesia (3,410 Gg CO2e yr−1) and Malaysia (1,288 Gg CO2e yr−1). The patterns described serve as a baseline by which countries can assess their mangrove soil C stocks and potential emissions from mangrove deforestation.

Determining effects of an all weather logging road on winter woodland caribou habitat use in south-eastern Manitoba

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Doug W. Schindler

2007-04-01

Full Text Available The Owl Lake boreal woodland caribou population is the most southerly population in Manitoba. It is provincially ranked as a High Conservation Concern Population. Forestry operations exist in the area and there are plans for further forest harvest and renewal. The Happy Lake logging road is the only main access through the Owl Lake winter range. This logging road is currently closed to the public and access is limited to forestry operations during specific times of the year. An integrated forestry/caribou management strategy for the area provides for the maintenance of minimum areas of functional habitat. Habitat quality along the road was compared to habitat quality in the winter core use areas, within the winter range and outside the winter range. To evaluate the extent of functional habitat near the road, we conducted animal location and movement analysis using GPS data collected from January 2002 to March 2006. Habitat quality in the winter range, core use areas and along the road were assessed and found to be similar. Analysis of caribou locations and movement illustrate less use of high quality habitat adjacent to the Happy Lake Road. Loss of functional habitat is suggested to occur within 1 kilometre of the road. This potential loss of functional habitat should be incorporated into integrated forestry and caribou conservation strategies. Road management is recommended to minimize the potential sensory disturbance and associated impacts of all weather access on boreal woodland caribou.

Latitudinal Patterns in European Seagrass Carbon Reserves: Influence of Seasonal Fluctuations versus Short-Term Stress and Disturbance Events

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Laura M. Soissons

2018-02-01

Full Text Available Seagrass meadows form highly productive and valuable ecosystems in the marine environment. Throughout the year, seagrass meadows are exposed to abiotic and biotic variations linked to (i seasonal fluctuations, (ii short-term stress events such as, e.g., local nutrient enrichment, and (iii small-scale disturbances such as, e.g., biomass removal by grazing. We hypothesized that short-term stress events and small-scale disturbances may affect seagrass chance for survival in temperate latitudes. To test this hypothesis we focused on seagrass carbon reserves in the form of starch stored seasonally in rhizomes, as these have been defined as a good indicator for winter survival. Twelve Zostera noltei meadows were monitored along a latitudinal gradient in Western Europe to firstly assess the seasonal change of their rhizomal starch content. Secondly, we tested the effects of nutrient enrichment and/or biomass removal on the corresponding starch content by using a short-term manipulative field experiment at a single latitude in the Netherlands. At the end of the growing season, we observed a weak but significant linear increase of starch content along the latitudinal gradient from south to north. This agrees with the contention that such reserves are essential for regrowth after winter, which is more severe in the north. In addition, we also observed a weak but significant positive relationship between starch content at the beginning of the growing season and past winter temperatures. This implies a lower regrowth potential after severe winters, due to diminished starch content at the beginning of the growing season. Short-term stress and disturbances may intensify these patterns, because our manipulative experiments show that when nutrient enrichment and biomass loss co-occurred at the end of the growing season, Z. noltei starch content declined. In temperate zones, the capacity of seagrasses to accumulate carbon reserves is expected to determine carbon

Latitudinal Patterns in European Seagrass Carbon Reserves: Influence of Seasonal Fluctuations versus Short-Term Stress and Disturbance Events

Science.gov (United States)

Soissons, Laura M.; Haanstra, Eeke P.; van Katwijk, Marieke M.; Asmus, Ragnhild; Auby, Isabelle; Barillé, Laurent; Brun, Fernando G.; Cardoso, Patricia G.; Desroy, Nicolas; Fournier, Jerome; Ganthy, Florian; Garmendia, Joxe-Mikel; Godet, Laurent; Grilo, Tiago F.; Kadel, Petra; Ondiviela, Barbara; Peralta, Gloria; Puente, Araceli; Recio, Maria; Rigouin, Loic; Valle, Mireia; Herman, Peter M. J.; Bouma, Tjeerd J.

2018-01-01

Seagrass meadows form highly productive and valuable ecosystems in the marine environment. Throughout the year, seagrass meadows are exposed to abiotic and biotic variations linked to (i) seasonal fluctuations, (ii) short-term stress events such as, e.g., local nutrient enrichment, and (iii) small-scale disturbances such as, e.g., biomass removal by grazing. We hypothesized that short-term stress events and small-scale disturbances may affect seagrass chance for survival in temperate latitudes. To test this hypothesis we focused on seagrass carbon reserves in the form of starch stored seasonally in rhizomes, as these have been defined as a good indicator for winter survival. Twelve Zostera noltei meadows were monitored along a latitudinal gradient in Western Europe to firstly assess the seasonal change of their rhizomal starch content. Secondly, we tested the effects of nutrient enrichment and/or biomass removal on the corresponding starch content by using a short-term manipulative field experiment at a single latitude in the Netherlands. At the end of the growing season, we observed a weak but significant linear increase of starch content along the latitudinal gradient from south to north. This agrees with the contention that such reserves are essential for regrowth after winter, which is more severe in the north. In addition, we also observed a weak but significant positive relationship between starch content at the beginning of the growing season and past winter temperatures. This implies a lower regrowth potential after severe winters, due to diminished starch content at the beginning of the growing season. Short-term stress and disturbances may intensify these patterns, because our manipulative experiments show that when nutrient enrichment and biomass loss co-occurred at the end of the growing season, Z. noltei starch content declined. In temperate zones, the capacity of seagrasses to accumulate carbon reserves is expected to determine carbon-based regrowth

Evolution of stratospheric ozone during winter 2002/2003 as observed by a ground-based millimetre wave radiometer at Kiruna, Sweden

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U. Raffalski

2005-01-01

Full Text Available We present ozone measurements from the millimetre wave radiometer installed at the Swedish Institute of Space Physics (Institutet för rymdfysik, IRF in Kiruna (67.8° N, 20.4° E, 420 m asl. Nearly continuous operation in the winter of 2002/2003 allows us to give an overview of ozone evolution in the stratosphere between 15 and 55 km. In this study we present a detailed analysis of the Arctic winter 2002/2003. By means of a methodology using equivalent latitudes we investigate the meteorological processes in the stratosphere during the entire winter/spring period. During the course of the winter strong mixing into the vortex took place in the middle and upper stratosphere as a result of three minor and one major warming event, but no evidence was found for significant mixing in the lower stratosphere. Ozone depletion in the lower stratosphere during this winter was estimated by measurements on those days when Kiruna was well inside the Arctic polar vortex. The days were carefully chosen using a definition of the vortex edge based on equivalent latitudes. At the 475 K isentropic level a cumulative ozone loss of about 0.5 ppmv was found starting in January and lasting until mid-March. The early ozone loss is probably a result of the very cold temperatures in the lower stratosphere in December and the geographical extension of the vortex to lower latitudes where solar irradiation started photochemical ozone loss in the pre-processed air. In order to correct for dynamic effects of the ozone variation due to diabatic subsidence of air masses inside the vortex, we used N2O measurements from the Odin satellite for the same time period. The derived ozone loss in the lower stratosphere between mid-December and mid-March varies between 1.1±0.1 ppmv on the 150 ppbv N2O isopleth and 1.7±0.1 ppmv on the 50 ppbv N2O isopleth.

Winter fidelity and apparent survival of lesser snow goose populations in the Pacific flyway

Science.gov (United States)

Williams, C.K.; Samuel, M.D.; Baranyuk, Vasily V.; Cooch, E.G.; Kraege, Donald K.

2008-01-01

The Beringia region of the Arctic contains 2 colonies of lesser snow geese (Chen caerulescens caerulescens) breeding on Wrangel Island, Russia, and Banks Island, Canada, and wintering in North America. The Wrangel Island population is composed of 2 subpopulations from a sympatric breeding colony but separate wintering areas, whereas the Banks Island population shares a sympatric wintering area in California, USA, with one of the Wrangel Island subpopulations. The Wrangel Island colony represents the last major snow goose population in Russia and has fluctuated considerably since 1970, whereas the Banks Island population has more than doubled. The reasons for these changes are unclear, but hypotheses include independent population demographics (survival and recruitment) and immigration and emigration among breeding or wintering populations. These demographic and movement patterns have important ecological and management implications for understanding goose population structure, harvest of admixed populations, and gene flow among populations with separate breeding or wintering areas. From 1993 to 1996, we neckbanded molting birds at their breeding colonies and resighted birds on the wintering grounds. We used multistate mark-recapture models to evaluate apparent survival rates, resighting rates, winter fidelity, and potential exchange among these populations. We also compared the utility of face stain in Wrangel Island breeding geese as a predictor of their wintering area. Our results showed similar apparent survival rates between subpopulations of Wrangel Island snow geese and lower apparent survival, but higher emigration, for the Banks Island birds. Males had lower apparent survival than females, most likely due to differences in neckband loss. Transition between wintering areas was low (exchange between the Banks and northern Wrangel Island populations. Face staining was an unreliable indicator of wintering area. Our findings suggest that northern and southern

Effects of Revegetation on Soil Organic Carbon Storage and Erosion-Induced Carbon Loss under Extreme Rainstorms in the Hill and Gully Region of the Loess Plateau

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Yujin Li

2016-04-01

Full Text Available Background: The Loess Plateau, an ecologically vulnerable region, has long been suffering from serious soil erosion. Revegetation has been implemented to control soil erosion and improve ecosystems in the Loess Plateau region through a series of ecological recovery programs. However, the increasing atmospheric CO2 as a result of human intervention is affecting the climate by global warming, resulting in the greater frequency and intensity of extreme weather events, such as storms that may weaken the effectiveness of revegetation and cause severe soil erosion. Most research to date has evaluated the effectiveness of revegetation on soil properties and soil erosion of different land use or vegetation types. Here, we study the effect of revegetation on soil organic carbon (SOC storage and erosion-induced carbon loss related to different plant communities, particularly under extreme rainstorm events. Materials and methods: The erosion-pin method was used to quantify soil erosion, and soil samples were taken at soil depths of 0–5 cm, 5–10 cm and 10–20 cm to determine the SOC content for 13 typical hillside revegetation communities in the year of 2013, which had the highest rainfall with broad range, long duration and high intensity since 1945, in the Yanhe watershed. Results and discussion: The SOC concentrations of all plant communities increased with soil depth when compared with slope cropland, and significant increases (p < 0.05 were observed for most shrub and forest communities, particularly for natural ones. Taking the natural secondary forest community as reference (i.e., soil loss and SOC loss were both 1.0, the relative soil loss and SOC loss of the other 12 plant communities in 2013 ranged from 1.5 to 9.4 and 0.30 to 1.73, respectively. Natural shrub and forest communities showed greater resistance to rainstorm erosion than grassland communities. The natural grassland communities with lower SOC content produced lower SOC loss even

Ecological impacts of winter water level drawdowns on lake littoral zones: A review

Science.gov (United States)

Roy, Allison

2017-01-01

Freshwater littoral zones harbor diverse ecological communities and serve numerous ecosystem functions that are controlled, in part, by natural water level fluctuations. However, human alteration of lake hydrologic regimes beyond natural fluctuations threaten littoral zone ecological integrity. One type of hydrologic alteration in lakes is winter water level drawdowns, which are frequently employed for hydropower, flood control, and macrophyte control, among other purposes. Here, we synthesize the abiotic and biotic responses to annual and novel winter water level drawdowns in littoral zones of lakes and reservoirs. The dewatering, freezing, and increased erosion of exposed lakebeds drive changes in the littoral zone. Shoreline-specific physicochemical conditions such as littoral slope and shoreline exposure further induce modifications. Loss of fine sediment decreases nutrient availability over time, but desiccation may promote a temporary nutrient pulse upon re-inundation. Annual winter drawdowns can decrease taxonomic richness of macrophytes and benthic invertebrates and shift assemblage composition to favor taxa with r-selected life history strategies and with functional traits resistant to direct and indirect drawdown effects. Fish assemblages, though less directly affected by winter drawdowns (except where there is critically low dissolved oxygen), experience negative effects via indirect pathways like decreased food resources and spawning habitat. We identify eight general research gaps to guide future research that could improve our understanding about the complex effects of winter drawdowns on littoral zone ecology.

Importance of a winter dinoflagellate-microflagellate bloom in the Patuxent River estuary

Science.gov (United States)

Sellner, K. G.; Lacouture, R. V.; Cibik, S. J.; Brindley, A.; Brownlee, S. G.

1991-01-01

A dense bloom of Katodinium rotundatum was observed in the Patuxent River estuary from December to February 1989. The dinoflagellate dominated phytoplankton densities reaching 10 8 cells l -1 and contributed up to 1900 μgC l -1 in near-surface depths. The bloom maintained a distinct patch extending over 10-25 km of the estuary or approximately one-third to one-half of the total estuary (salinities from 5-13 ppt) and was restricted to regions immediately upriver of the transition between the shallow upriver (3-4 m) and deeper lower estuary (10 m). Daily measurements collected in the primary bloom area at the same time each day in the study area indicated 80- and 120-fold variations in chlorophyll and cell densities from day to day. Densities of potential grazers in the region were high with rotifers, primarily Synchaeta baltica, reaching densities of 1000 l -1 in early winter, and the copepod Eurytemora affinis reaching levels exceeding 1·15 × 10 5 m -3 in February. Estimates of grazing pressure by these planktonic herbivores indicated substantial grazing losses for the bloom, with up to 67% of bloom biomass consumed day -1 in February. Nutrient concentrations and ratios of N/P during the bloom suggested potentially N-limited conditions; bloom demise was coincident with a shift to high N/P ratios and high river flows. These data as well as other historical data suggest that dinoflagellate blooms in the lower Patuxent River estuary could be the primary source of carbon to the system during the winter and supply a large reservoir of labile organic matter to planktonic secondary producers prior to annual spring diatom blooms in the region.

Slowing the rate of loss of mineral wetlands on human dominated landscapes - Diversification of farmers markets to include carbon (Invited)

Science.gov (United States)

Creed, I. F.; Badiou, P.; Lobb, D.

2013-12-01

Canada is the fourth-largest exporter of agriculture and agri-food products in the world (exports valued at 28B), but instability of agriculture markets can make it difficult for farmers to cope with variability, and new mechanisms are needed for farmers to achieve economic stability. Capitalizing on carbon markets will help farmers achieve environmentally sustainable economic performance. In order to have a viable carbon market, governments and industries need to know what the carbon capital is and what potential there is for growth, and farmers need financial incentives that will not only allow them to conserve existing wetlands but that will also enable them to restore wetlands while making a living. In southern Ontario, farmers' needs to maximize the return on investment on marginal lands have resulted in loss of 70-90% of wetlands, making this region one of the most threatened region in terms of wetland degradation and loss in Canada. Our project establishes the role that mineral wetlands have in the net carbon balance by contributing insight into the potential benefits to carbon management provided by wetland restoration efforts in these highly degraded landscapes. The goal was to establish the magnitude of carbon offsets that could be achieved through wetland conservation (securing existing carbon stocks) and restoration (creating new carbon stocks). The experimental design was to focus on (1) small (0.2-2.0 ha) and (2) isolated (no inflow or outflow) mineral wetlands with the greatest restoration potential that included (3) a range of restoration ages (drained (0 yr), 3 yr, 6 yr, 12 yr, 20 yr, 35 yr, intact marshes) to capture potential changes in rates of carbon sequestration with restoration age of wetland. From each wetland, wetland soil carbon pools samples were collected at four positions: centre of wetland (open-water); emergent vegetation zone; wet meadow zone where flooding often occurs (i.e., high water mark); and upland where flooding rarely

Effects of elevated O3 concentration on winter wheat and rice yields in the Yangtze River Delta, China

International Nuclear Information System (INIS)

Wang Xiaoke; Zhang Qianqian; Zheng Feixiang; Zheng Qiwei; Yao Fangfang; Chen Zhan; Zhang Weiwei; Hou Peiqiang; Feng Zhaozhong; Song Wenzhi; Feng Zongwei; Lu Fei

2012-01-01

The effects of a continuing rise of ambient ozone on crop yield will seriously threaten food security in China. In the Yangtze River Delta, a rapidly developing and seriously air polluted region in China, innovative open-top chambers have been established to fumigate winter wheat and rice in situ with elevated O 3 . Five years of study have shown that the yields of wheat and rice decreased with increasing O 3 concentration. There were significant relationships between the relative yield and AOT40 (accumulated hourly O 3 concentration over 40 ppb) for both winter wheat and rice. Winter wheat was more sensitive to O 3 than rice. O 3 -induced yield declines were attributed primarily to 1000-grain weight and harvest index for winter wheat, and attributed primarily to grain number per panicle and harvest index for rice. Control of ambient O 3 pollution and breeding of O 3 tolerant crops are urgent to guarantee food security in China. - Highlights: ► The wheat and rice response to ozone had been investigated for five years in China. ► There were significant relationships between relative crop yields and AOT40 dose. ► O 3 -induced wheat yield loss was primarily due to 1000-grain weight and harvest index. ► O 3 -induced rice yield loss was primarily due to grains per panicle and harvest index. ► Wheat and rice in this study are more sensitive to O 3 than previous investigations. - The dose–response relationships derived from field fumigation experiments over 5 years can be used to accurately estimate crop losses in China.

Antecedent conditions control carbon loss and downstream water quality from shallow, damaged peatlands.

Science.gov (United States)

Grand-Clement, E; Luscombe, D J; Anderson, K; Gatis, N; Benaud, P; Brazier, R E

2014-09-15

Losses of dissolved organic carbon (DOC) from drained peatlands are of concern, due to the effects this has on the delivery of ecosystem services, and especially on the long-term store of carbon and the provision of drinking water. Most studies have looked at the effect of drainage in deep peat; comparatively, little is known about the behaviour of shallow, climatically marginal peatlands. This study examines water quality (DOC, Abs(400), pH, E4/E6 and C/C) during rainfall events from such environments in the south west UK, in order to both quantify DOC losses, and understand their potential for restoration. Water samples were taken over a 19 month period from a range of drains within two different experimental catchments in Exmoor National Park; data were analysed on an event basis. DOC concentrations ranging between 4 and 21 mg L(-1) are substantially lower than measurements in deep peat, but remain problematic for the water treatment process. Dryness plays a critical role in controlling DOC concentrations and water quality, as observed through spatial and seasonal differences. Long-term changes in depth to water table (30 days before the event) are likely to impact on DOC production, whereas discharge becomes the main control over DOC transport at the time scale of the rainfall/runoff event. The role of temperature during events is attributed to an increase in the diffusion of DOC, and therefore its transport. Humification ratios (E4/E6) consistently below 5 indicate a predominance of complex humic acids, but increased decomposition during warmer summer months leads to a comparatively higher losses of fulvic acids. This work represents a significant contribution to the scientific understanding of the behaviour and functioning of shallow damaged peatlands in climatically marginal locations. The findings also provide a sound baseline knowledge to support research into the effects of landscape restoration in the future. Crown Copyright © 2014. Published by

Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

Energy Technology Data Exchange (ETDEWEB)

Wang, Yinxi; Liu, Dan; Zhang, Huifeng; Wang, Yixin [Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, 100191 (China); Wei, Ling [Beijing Center for Physical & Chemical Analysis, Beijing 100089 (China); Liu, Yutong [School of Life Science, Beijing Normal University, Beijing 100875 (China); Liao, Jieying [Department of Translational Medicine, Xiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361024 (China); Gao, Hui-Ming [Model Animal Research Center of Nanjing University, Nanjing 211800 (China); Zhou, Hui, E-mail: hardhui@gmail.com [Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, 100191 (China)

2017-05-01

Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPH oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm{sup 2} induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm{sup 2}) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91{sup phox}, p47{sup phox} and p40{sup phox}); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47{sup phox} and p67{sup phox} translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to

Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

International Nuclear Information System (INIS)

Wang, Yinxi; Liu, Dan; Zhang, Huifeng; Wang, Yixin; Wei, Ling; Liu, Yutong; Liao, Jieying; Gao, Hui-Ming; Zhou, Hui

2017-01-01

Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPH oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm 2 induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm 2 ) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91 phox , p47 phox and p40 phox ); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47 phox and p67 phox translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to oxidative damage to DA neurons. Our

Evaluating of the spatial heterogeneity of soil loss tolerance and its effects on erosion risk in the carbonate areas of southern China

Directory of Open Access Journals (Sweden)

Y. Li

2017-05-01

Full Text Available Soil loss tolerance (T value is one of the criteria in determining the necessity of erosion control measures and ecological restoration strategy. However, the validity of this criterion in subtropical karst regions is strongly disputed. In this study, T value is calculated based on soil formation rate by using a digital distribution map of carbonate rock assemblage types. Results indicated a spatial heterogeneity and diversity in soil loss tolerance. Instead of only one criterion, a minimum of three criteria should be considered when investigating the carbonate areas of southern China because the one region, one T value concept may not be applicable to this region. T value is proportionate to the amount of argillaceous material, which determines the surface soil thickness of the formations in homogenous carbonate rock areas. Homogenous carbonate rock, carbonate rock intercalated with clastic rock areas and carbonate/clastic rock alternation areas have T values of 20, 50 and 100 t/(km2 a, and they are extremely, severely and moderately sensitive to soil erosion. Karst rocky desertification (KRD is defined as extreme soil erosion and reflects the risks of erosion. Thus, the relationship between T value and erosion risk is determined using KRD as a parameter. The existence of KRD land is unrelated to the T value, although this parameter indicates erosion sensitivity. Erosion risk is strongly dependent on the relationship between real soil loss (RL and T value rather than on either erosion intensity or the T value itself. If RL > > T, then the erosion risk is high despite of a low RL. Conversely, if T > > RL, then the soil is safe although RL is high. Overall, these findings may clarify the heterogeneity of T value and its effect on erosion risk in a karst environment.

Density functional theory calculations of energy-loss carbon near-edge spectra of small diameter armchair and zigzag nanotubes: Core-hole, curvature, and momentum-transfer orientation effects

International Nuclear Information System (INIS)

Titantah, J.T.; Lamoen, D.; Jorissen, K.

2004-01-01

We perform density functional theory calculations on a series of armchair and zigzag nanotubes of diameters less than 1 nm using the all-electron full-potential(-linearized)-augmented-plane-wave method. Emphasis is laid on the effects of curvature, the electron-beam orientation, and the inclusion of the core hole on the carbon electron-energy-loss K edge. The electron-energy-loss near-edge spectra of all the studied tubes show strong curvature effects compared to that of flat graphene. The curvature-induced π-σ hybridization is shown to have a more drastic effect on the electronic properties of zigzag tubes than on those of armchair tubes. We show that the core-hole effect must be accounted for in order to correctly reproduce electron-energy-loss measurements. We also find that the energy-loss near-edge spectra of these carbon systems are dominantly dipole selected and that they can be expressed simply as a proportionality with the local momentum projected density of states, thus portraying the weak energy dependence of the transition matrix elements. Compared to graphite, we report a reduction in the anisotropy as seen on the energy-loss near-edge spectra of carbon nanotubes

Impacts of extreme winter warming events on plant physiology in a sub-Arctic heath community.

Science.gov (United States)

Bokhorst, Stef; Bjerke, Jarle W; Davey, Matthew P; Taulavuori, Kari; Taulavuori, Erja; Laine, Kari; Callaghan, Terry V; Phoenix, Gareth K

2010-10-01

Insulation provided by snow cover and tolerance of freezing by physiological acclimation allows Arctic plants to survive cold winter temperatures. However, both the protection mechanisms may be lost with winter climate change, especially during extreme winter warming events where loss of snow cover from snow melt results in exposure of plants to warm temperatures and then returning extreme cold in the absence of insulating snow. These events cause considerable damage to Arctic plants, but physiological responses behind such damage remain unknown. Here, we report simulations of extreme winter warming events using infrared heating lamps and soil warming cables in a sub-Arctic heathland. During these events, we measured maximum quantum yield of photosystem II (PSII), photosynthesis, respiration, bud swelling and associated bud carbohydrate changes and lipid peroxidation to identify physiological responses during and after the winter warming events in three dwarf shrub species: Empetrum hermaphroditum, Vaccinium vitis-idaea and Vaccinium myrtillus. Winter warming increased maximum quantum yield of PSII, and photosynthesis was initiated for E. hermaphroditum and V. vitis-idaea. Bud swelling, bud carbohydrate decreases and lipid peroxidation were largest for E. hermaphroditum, whereas V. myrtillus and V. vitis-idaea showed no or less strong responses. Increased physiological activity and bud swelling suggest that sub-Arctic plants can initiate spring-like development in response to a short winter warming event. Lipid peroxidation suggests that plants experience increased winter stress. The observed differences between species in physiological responses are broadly consistent with interspecific differences in damage seen in previous studies, with E. hermaphroditum and V. myrtillus tending to be most sensitive. This suggests that initiation of spring-like development may be a major driver in the damage caused by winter warming events that are predicted to become more

Fossil and non-fossil sources of organic carbon (OC and elemental carbon (EC in Göteborg, Sweden

Directory of Open Access Journals (Sweden)

S. Szidat

2009-03-01

Full Text Available Particulate matter was collected at an urban site in Göteborg (Sweden in February/March 2005 and in June/July 2006. Additional samples were collected at a rural site for the winter period. Total carbon (TC concentrations were 2.1–3.6 μg m⁻³, 1.8–1.9 μg m⁻³, and 2.2–3.0 μg m⁻³ for urban/winter, rural/winter, and urban/summer conditions, respectively. Elemental carbon (EC, organic carbon (OC, water-insoluble OC (WINSOC, and water-soluble OC (WSOC were analyzed for ¹⁴C in order to distinguish fossil from non-fossil emissions. As wood burning is the single major source of non-fossil EC, its contribution can be quantified directly. For non-fossil OC, the wood-burning fraction was determined independently by levoglucosan and ¹⁴C analysis and combined using Latin-hypercube sampling (LHS. For the winter period, the relative contribution of EC from wood burning to the total EC was >3 times higher at the rural site compared to the urban site, whereas the absolute concentrations of EC from wood burning were elevated only moderately at the rural compared to the urban site. Thus, the urban site is substantially more influenced by fossil EC emissions. For summer, biogenic emissions dominated OC concentrations most likely due to secondary organic aerosol (SOA formation. During both seasons, a more pronounced fossil signal was observed for Göteborg than has previously been reported for Zurich, Switzerland. Analysis of air mass origin using back trajectories suggests that the fossil impact was larger when local sources dominated, whereas long-range transport caused an enhanced non-fossil signal. In comparison to other European locations, concentrations of levoglucosan and other monosaccharide anhydrides were low for the urban and the rural site in the area of Göteborg during winter.

Winter maintenance performance measure.

Science.gov (United States)

2016-01-01

The Winter Performance Index is a method of quantifying winter storm events and the DOTs response to them. : It is a valuable tool for evaluating the States maintenance practices, performing post-storm analysis, training : maintenance personnel...

Carbon dioxide exchange over agricultural landscape using eddy correlation and footprint modelling

DEFF Research Database (Denmark)

Søgaard, H.; Jensen, N.O.; Bøgh, E.

2003-01-01

Within an agricultural landscape of western Denmark, the carbon dioxide exchange was studied throughout a year (April 1998-March 1999). During the growing season, five eddy correlation systems were operated in parallel over some of the more important crops (winter wheat, winter barley, spring...

2010 winter games tracks energy in real time

Energy Technology Data Exchange (ETDEWEB)

Anon.

2010-01-15

An online energy tracker was developed by BC Hydro to publicly monitor the real-time energy consumption at the Vancouver 2010 Olympic winter game sites within Vancouver, Richmond, Whistler and Whistler Blackcomb. The venues and associated sites participating in the live energy tracking project were the Richmond Olympic Oval, Canada Hockey Place, Vancouver Olympic/Paralympic Centre, South East False Creek Community Centre, Whistler Blackcomb Roundhouse Lodge and snowmaking facilities, and the Olympic and Paralympic Villages. The system was developed to allow venue managers to optimize their use of electricity on an hourly and daily basis. An energy tracking display board developed by Pulse Energy enabled them to compare their performance to similar facilities in real time, and to determine the greenhouse gas savings achieved as result of building and operating practices. Some venues had the potential to save as much as 15 to 20 per cent in energy costs with corresponding reductions in carbon emissions. Efficiency and conservation was built into the design of many new venues. The retrofits made to several existing buildings will continue to contribute to British Columbia's conservation goals long after the 2010 winter games are over.

Estimating winter survival of winter wheat by simulations of plant frost tolerance

NARCIS (Netherlands)

Bergjord Olsen, A.K.; Persson, T.; Wit, de A.; Nkurunziza, L.; Sindhøj, E.; Eckersten, H.

2018-01-01

Based on soil temperature, snow depth and the grown cultivar's maximum attainable level of frost tolerance (LT50c), the FROSTOL model simulates development of frost tolerance (LT50) and winter damage, thereby enabling risk calculations for winter wheat survival. To explore the accuracy of this

Incorporating Yearly Derived Winter Wheat Maps Into Winter Wheat Yield Forecasting Model

Science.gov (United States)

Skakun, S.; Franch, B.; Roger, J.-C.; Vermote, E.; Becker-Reshef, I.; Justice, C.; Santamaría-Artigas, A.

2016-01-01

Wheat is one of the most important cereal crops in the world. Timely and accurate forecast of wheat yield and production at global scale is vital in implementing food security policy. Becker-Reshef et al. (2010) developed a generalized empirical model for forecasting winter wheat production using remote sensing data and official statistics. This model was implemented using static wheat maps. In this paper, we analyze the impact of incorporating yearly wheat masks into the forecasting model. We propose a new approach of producing in season winter wheat maps exploiting satellite data and official statistics on crop area only. Validation on independent data showed that the proposed approach reached 6% to 23% of omission error and 10% to 16% of commission error when mapping winter wheat 2-3 months before harvest. In general, we found a limited impact of using yearly winter wheat masks over a static mask for the study regions.

Winter weather demand considerations.

Science.gov (United States)

2015-04-01

Winter weather has varied effects on travel behavior. Using 418 survey responses from the Northern Virginia : commuting area of Washington, D.C. and binary logit models, this study examines travel related changes under : different types of winter wea...

The influence of sowing period and seeding norm on autumn vegetation, winter hardiness and yield of winter cereal crops

Directory of Open Access Journals (Sweden)

Potapova G. N.

2017-10-01

Full Text Available the winter wheat and triticale in the middle part of the Ural Mountains haven’t been seeded before. The technology of winter crop cultivation should be improved due to the production of new varieties of winter rye. Winter hardiness and yield of winter rye are higher in comparison with winter triticale and especially with winter wheat. The sowing period and the seeding rate influence the amount of yield and winter hardiness. The winter hardiness of winter cereals and the yield of the rye variety Iset sowed on August 25 and the yield of the triticale variety Bashkir short-stalked and wheat Kazanskaya 560 sowed on August 15 were higher. It is important to sow winter grain in local conditions in the second half of August. The sowing this period allows to provide plants with the necessary amount of positive temperatures (450–500 °C. This helps the plants to form 3–4 shoots of tillering and a mass of 10 dry plants reaching 3–5 grams. The winter grain crops in the middle part of the Ural Mountains should be sown with seeding rates of 6 and 7 million of sprouting grains per 1 ha, and the seeds must be cultivated with fungicidal preparation before seeding.

Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model.

Science.gov (United States)

Brodin, Anders; Nilsson, Jan-Åke; Nord, Andreas

2017-09-01

Several species of small birds are resident in boreal forests where environmental temperatures can be -20 to -30 °C, or even lower, in winter. As winter days are short, and food is scarce, winter survival is a challenge for small endothermic animals. A bird of this size will have to gain almost 10% of its lean body mass in fat every day to sustain overnight metabolism. Birds such as parids (titmice and chickadees) can use facultative hypothermia, a process in which body temperature is actively down-regulated to a specific level, to reduce heat loss and thus save energy. During cold winter nights, these birds may decrease body temperature from the normal from 42 ° down to 35 °C, or even lower in some species. However, birds are unable to move in this deep hypothermic state, making it a risky strategy if predators are around. Why, then, do small northern birds enter a potentially dangerous physiological state for a relatively small reduction in energy expenditure? We used stochastic dynamic programming to investigate this. Our model suggests that the use of nocturnal hypothermia at night is paramount in these biomes, as it would increase winter survival for a small northern bird by 58% over a winter of 100 days. Our model also explains the phenomenon known as winter fattening, and its relationship to thermoregulation, in northern birds.

Tropical North Atlantic ocean-atmosphere interactions synchronize forest carbon losses from hurricanes and Amazon fires

OpenAIRE

Chen, Y; Randerson, JT; Morton, DC

2015-01-01

©2015. American Geophysical Union. All Rights Reserved. We describe a climate mode synchronizing forest carbon losses from North and South America by analyzing time series of tropical North Atlantic sea surface temperatures (SSTs), landfall hurricanes and tropical storms, and Amazon fires during 1995-2013. Years with anomalously high tropical North Atlantic SSTs during March-June were often followed by a more active hurricane season and a larger number of satellite-detected fires in the south...

A survey of honey bee colony losses in the U.S., fall 2007 to spring 2008.

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Dennis van Engelsdorp

Full Text Available BACKGROUND: Honey bees are an essential component of modern agriculture. A recently recognized ailment, Colony Collapse Disorder (CCD, devastates colonies, leaving hives with a complete lack of bees, dead or alive. Up to now, estimates of honey bee population decline have not included losses occurring during the wintering period, thus underestimating actual colony mortality. Our survey quantifies the extent of colony losses in the United States over the winter of 2007-2008. METHODOLOGY/PRINCIPAL FINDINGS: Surveys were conducted to quantify and identify management factors (e.g. operation size, hive migration that contribute to high colony losses in general and CCD symptoms in particular. Over 19% of the country's estimated 2.44 million colonies were surveyed. A total loss of 35.8% of colonies was recorded; an increase of 11.4% compared to last year. Operations that pollinated almonds lost, on average, the same number of colonies as those that did not. The 37.9% of operations that reported having at least some of their colonies die with a complete lack of bees had a total loss of 40.8% of colonies compared to the 17.1% loss reported by beekeepers without this symptom. Large operations were more likely to have this symptom suggesting that a contagious condition may be a causal factor. Sixty percent of all colonies that were reported dead in this survey died without dead bees, and thus possibly suffered from CCD. In PA, losses varied with region, indicating that ambient temperature over winter may be an important factor. CONCLUSIONS/SIGNIFICANCE: Of utmost importance to understanding the recent losses and CCD is keeping track of losses over time and on a large geographic scale. Given that our surveys are representative of the losses across all beekeeping operations, between 0.75 and 1.00 million honey bee colonies are estimated to have died in the United States over the winter of 2007-2008. This article is an extensive survey of U.S. beekeepers

Sources and contributions of wood smoke during winter in London

Science.gov (United States)

Crilley, Leigh; Bloss, William; Yin, Jianxin; Beddows, David; Harrison, Roy; Zotter, Peter; Prevot, Andre; Green, David

2014-05-01

Determining the contribution of wood smoke in large urban centres such as London is becoming increasingly important with the changing nature of domestic heating partly due to the installation of biomass burning heaters to meet renewable energy targets imposed by the EU and also a rise in so-called recreational burning for aesthetic reasons (Fuller et al., 2013). Recent work in large urban centres (London, Paris and Berlin) has demonstrated an increase in the contribution of wood smoke to ambient particles during winter that can at times exceed traffic emissions. In Europe, biomass burning has been identified as a major cause of exceedances of European air quality limits during winter (Fuller et al., 2013). In light of the changing nature of emissions in urban areas there is a need for on-going measurements to assess the impact of biomass burning in cities like London. Therefore we aimed to determine quantitatively the contribution of biomass burning in London and surrounding rural areas. We also aimed to determine whether local emissions or regional sources were the main source of biomass burning in London. Sources of wood smoke during winter in London were investigated at an urban background site (North Kensington) and two surrounding rural sites (Harwell and Detling) by analysing selected wood smoke chemical tracers. Concentrations of levoglucosan, elemental carbon (EC), organic carbon (OC) and K+ were generally well correlated, indicating a similar source of these species at the three sites. Based on the conversion factor for levoglucosan, mean wood smoke mass at Detling, North Kensington and Harwell was 0.78, 0.87 and 1.0 µg m-3, respectively. At all the sites, biomass burning was found to be a source of OC and EC, with the largest source of OC and EC found to be secondary organic aerosols and traffic emissions, respectively. Peaks in levoglucosan concentrations at the sites were observed to coincide with low ambient temperature, suggesting domestic heating as

Hibernating black bears (Ursus americanus) experience skeletal muscle protein balance during winter anorexia.

Science.gov (United States)

Lohuis, T D; Harlow, H J; Beck, T D I

2007-05-01

Black bears spend four to seven months every winter confined to their den and anorexic. Despite potential for skeletal muscle atrophy and protein loss, bears appear to retain muscle integrity throughout winter dormancy. Other authors have suggested that bears are capable of net protein anabolism during this time. The present study was performed to test this hypothesis by directly measuring skeletal muscle protein metabolism during the summer, as well as early and late hibernation periods. Muscle biopsies were taken from the vastus lateralis of six free-ranging bears in the summer, and from six others early in hibernation and again in late winter. Protein synthesis and breakdown were measured on biopsies using (14)C-phenylalanine as a tracer. Muscle protein, nitrogen, and nucleic acid content, as well as nitrogen stable isotope enrichment, were also measured. Protein synthesis was greater than breakdown in summer bears, suggesting that they accumulate muscle protein during periods of seasonal food availability. Protein synthesis and breakdown were both lower in winter compared to summer but were equal during both early and late denning, indicating that bears are in protein balance during hibernation. Protein and nitrogen content, nucleic acid, and stable isotope enrichment measurements of the biopsies support this conclusion.

Ecological and Geographical Selection of Winter Wheat (Triticum aestivum L. in Kazakhstan and Kyrgyzstan

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Р. А. Уразалієв

2009-10-01

Full Text Available As a result of the lead long-term selection works wint involving a World' s collection and intertype and intertype hybridization with purposeful selection on economic-biological attributes highly productive • grades of a winter wheat, with stability to various kinds of illnesses and high technological qualities of grain have been allocated. The adapted grades of a winter wheat for a various environment of various zones of the countries of the Central Asia that allows to realize potential opportunities of grades in different environments of cultivation and by that to prevent losses of a crop from biotic and abiotic stresses that allows to stabilize productivity and adaptability of culture in a zon winter husbandry are created. The long-term field experiences lead by us and laboratory analyses on a level of productivity, qualities of grain and stability to stresses allows to conclude, that alongside with a genotype, stabilityenvironmental conditions render strong and significant influence on all complex of selection attributes.

Characterization of Black and Brown Carbon Concentrations and Sources during winter in Beijing

Science.gov (United States)

Yan, Caiqing; Liu, Yue; Hansen, Anthony D. A.; Močnik, Griša; Zheng, Mei

2017-04-01

Carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), play important roles in air quality, human health, and climate change. A better understanding of sources of light-absorbing carbonaceous aerosol (including black carbon and brown carbon) is particular critical for formulating emission-based control strategies and reducing uncertainties in current aerosol radiative forcing estimates. Beijing, the capital of China, has experienced serious air pollution problems and high concentrations of carbonaceous aerosols in recent years, especially during heating seasons. During November and December of 2016, several severe haze episodes occurred in Beijing, with hourly average PM2.5 mass concentration up to 400 μg/m3. In this study, concentration levels and sources of black carbon and brown carbon were investigated based on 7-wavelength Aethalometer (AE-33) with combination of other PM2.5 chemical composition information. Contributions of traffic and non-traffic emissions (e.g., coal combustion, biomass burning) were apportioned, and brown carbon was separated from black carbon. Our preliminary results showed that (1) Concentrations of BC were around 5.3±4.2 μg/m3 during the study period, with distinct diurnal variations during haze and non-haze days. (2) Traffic emissions contributed to about 37±17% of total BC, and exhibited higher contributions during non-haze days compared to haze days. (3) Coal combustion was a major source of black carbon and brown carbon in Beijing, which was more significant compared to biomass burning. Sources and the relative contributions to black carbon and brown carbon during haze and non-haze days will be further discussed.

The nuclear winter

International Nuclear Information System (INIS)

Velikhow, Y.P.

1986-01-01

Nuclear winter is an example of possible secondary effects, and if we speak of secondary we are thinking of small-scale second-order effects, but a nuclear winter is not a second-order effect. If you calculate the amount of heat produced by a nuclear explosion, it is a very small amount which does not have any chance of changing the Earth's climate, but a nuclear explosion drives or stars some new mechanism - the mechanism of nuclear winter - after 100 megatons of dust are transferred to the upper atmosphere. Another example of such amplification is radioactive fall-out, especially long-life radioactive fall-out after the possible elimination of the nuclear power industry, nuclear storage and distribution of storage waste around the globe. This is a very powerful amplification mechanism

Assessment of winter fluxes of CO2 and CH4 in boreal forest soils of central Alaska estimated by the profile method and the chamber method: a diagnosis of methane emission and implications for the regional carbon budget

International Nuclear Information System (INIS)

Kim, Yongwon; Ueyama, Masahito; Harazono, Yoshinobu; Tanaka, Noriyuki; Nakagawa, Fumiko; Tsunogai, Urumu

2007-01-01

This research was carried out to estimate the winter fluxes of CO 2 and CH 4 using the concentration profile method and the chamber method in black spruce forest soils in central Alaska during the winter of 2004/5. The average winter fluxes of CO 2 and CH 4 by chamber and profile methods were 0.24 ± 0.06 (SE; standard error) and 0.21 ± 0.06 gCO 2 -C/m2/d, and 21.4 ± 5.6 and 21.4 ± 14 μgCH 4 -C/m2/hr. This suggests that the fluxes estimated by the two methods are not significantly different based on a one-way ANOVA with a 95% confidence level. The hypothesis on the processes of CH 4 transport/production/emission in underlying snow-covered boreal forest soils is proven by the pressure differences between air and in soil at 30 cm depth. The winter CO 2 emission corresponds to 23% of the annual CO 2 emitted from Alaska black spruce forest soils, which resulted in the sum of mainly root respiration and microbial respiration during the winter based on the (delta) 13 CO 2 of -2.25%. The average wintertime emissions of CO 2 and CH 4 were 49 ± 13 gCO 2 -C/m 2 /season and 0.11 ± 0.07 gCH 4 -C/m 2 /season, respectively. This implies that winter emissions of CO 2 and CH 4 are an important part of the annual carbon budget in seasonally snow-covered terrain of typical boreal forest soils

Pollution characteristic of VOCs of ambient air in winter and spring in Shijiazhuang City

Directory of Open Access Journals (Sweden)

Qing CHANG

2015-06-01

Full Text Available In order to further explore the pollution characteristics of volatile organic compounds in ambient air in winter and spring in Shijiazhuang City, the pollution characteristics of 62 volatile organic compounds (VOCs, monthly and quarterly variation, the correlation between VOCs and PM2.5, and the main sources of VOCs are investigated by using EPA TO-15 method. It shows that 40 organic compounds of the 64 VOCs have been quantitatively determined in winter and spring in the city, which are mainly acetone, benzene, carbon tetrachloride, dichloromethane, toluene, ethyl acetate, etc.. In the no-quantitatively determined components, higher ethanol, butyl acetate, butane etc. are detected. The VOCs concentration has positive correlation with the PM2.5 concentration during haze days.

White grubs (Cyclocephala flavipennis damaging perennial winter pastures in the South Region of Brazil

Directory of Open Access Journals (Sweden)

Paulo Gonçalves Duchini

Full Text Available ABSTRACT: Cyclocephala flavipennis Arrow, 1914 (Coleoptera: Melolonthidae, popularly known as white grub, is an insect widely disseminated in the South Region of Brazil. Despite the frequent occurrence of this white grub in areas cultivated with winter cereals, it is generally not considered a pest, since it feeds on straw and dead plant material. However, in 2015 and 2016, this insect has been identified as the damage-causing agent in the perennial winter pastures in Lages, Santa Catarina, Brazil. Damage was observed in patches and caused reduction in root depth and mass, resulting in loss of vigor, accelerated senescence in aerial parts, and death of tillers in Festuca arundinacea Schreb. and Dactylis glomerata L. plants.

Can GRACE detect winter snows in Japan?

Science.gov (United States)

Heki, Kosuke

2010-05-01

Current spatial resolution of the GRACE (Gravity Recovery and Climate Experiment) satellites is 300-400 km, and so its hydrological applications have been limited to continents and large islands. The Japanese Islands have width slightly smaller than this spatial resolution, but are known to show large amplitude seasonal changes in surface masses due mainly to winter snow. Such loads are responsible for seasonal crustal deformation observed with GEONET, a dense array of GPS (Global Positioning System) receivers in Japan (Heki, 2001). There is also a dense network of surface meteorological sensors for, e.g. snow depths, atmospheric pressures, etc. Heki (2004) showed that combined effects of surface loads, i.e. snow (predominant), atmosphere, soil moisture, dam impoundment, can explain seasonal crustal deformation observed by GPS to a large extent. The total weight of the winter snow in the Japanese Islands in its peak season may reach ~50 Gt. This is comparable to the annual loss of mountain glaciers in the Asian high mountains (Matsuo & Heki, 2010), and is above the detection level of GRACE. In this study, I use GRACE Level-2 Release-4 data from CSR, Univ. Texas, up to 2009 November, and evaluated seasonal changes in surface loads in and around the Japanese Islands. After applying a 350 km Gaussian filter and a de-striping filter, the peak-to-peak change of the water depth becomes ~4 cm in northern Japan. The maximum value is achieved in February-March. The region of large winter load spans from Hokkaido, Japan, to northeastern Honshu, which roughly coincides with the region of deep snow in Japan. Next I compiled snow depth data from surface meteorological observations, and converted them to loads using time-dependent snow density due to compaction. By applying the same spatial filter as the GRACE data, its spatial pattern becomes similar to the GRACE results. The present study suggests that GRACE is capable of detecting seasonal mass changes in an island arc not

Altered Plant Litter and Microbial Composition Lead to Topsoil Organic Carbon Loss Over a Shrub-encroachment Gradient in an Inner Mongolia Grassland

Science.gov (United States)

Zhou, L.; Li, H.; Shen, H.; Xu, Y.; Wang, Y.; Xing, A.; Fang, J.

2017-12-01

Over the past 150 years, shrub encroachment has occurred in arid and semi-arid ecosystems resulting from climate change and increased human disturbance. Previous studies have revealed that shrub encroachment has substantial effects on habitat heterogeneity, aboveground biomass and bulk carbon content of grasslands, thereby affecting the regional carbon balance. Soil organic carbon (SOC) is mainly derived from aboveground litter, root litter and root exudates and is metabolized by microorganisms. The quality and quantity of plant litter together with soil microbial biomass are important drivers of SOC accumulation. However, the mechanisms regulating soil carbon accumulation by the shrub encroachment remain unclear and molecular evidence is particularly lacking. We use the data of the chemical composition of plant tissues and SOC, and the soil microbial communities to identify the effects of shrub encroachment on SOC accumulation in the top layer along a gradient of natural shrub cover in the grasslands of Inner Mongolia. Our finding indicates that nitrogen-rich legume-shrub encroachment led to soil carbon accumulation in the shrub patch, with more extensive carbon loss observed in the grassy matrix, which resulted in an overall carbon loss. In the pure grassland, a higher abundance of cutin and suberin and a lower concentration of free lipids were detected, suggesting the preservation of recalcitrant polymers derived from herb inputs. In the shrub-encroached grasslands, the labile shrub leaves did not decompose alone but were mixed with herb litter to promote the degradation of SOC via the priming of microbial activities. The SOC remained unchanged in the shrub patches with the increasing shrub cover, which might have been caused by the replacement of prior carbon decompositions with the fresh input of shrub leaves. Similarly, the SOC decreased significantly with increasing shrub cover in the grassy matrix, which likely resulted from insufficient fresh plant inputs

The impact of tropospheric ozone pollution on trial plot winter wheat yields in Great Britain - An econometric approach

International Nuclear Information System (INIS)

Kaliakatsou, Evridiki; Bell, J. Nigel B.; Thirtle, Colin; Rose, Daniel; Power, Sally A.

2010-01-01

Numerous experiments have demonstrated reductions in the yields of cereal crops due to tropospheric O 3 , with losses of up to 25%. However, the only British econometric study on O 3 impacts on winter wheat yields, found that a 10% increase in AOT40 would decrease yields by only 0.23%. An attempt is made here to reconcile these observations by developing AOT40 maps for Great Britain and matching levels with a large number of standardised trial plot wheat yields from many sites over a 13-year period. Panel estimates (repeated measures on the same plots with time) show a 0.54% decrease in yields and it is hypothesised that plant breeders may have inadvertently selected for O 3 tolerance in wheat. Some support for this is provided by fumigations of cultivars of differing introduction dates. A case is made for the use of econometric as well as experimental studies in prediction of air pollution induced crop loss. - Econometric study of British winter wheat trial plot data suggests lower economic loss than predicted from experiments.

Calculations on charge state and energy loss of argon ions in partially and fully ionized carbon plasmas.

Science.gov (United States)

Barriga-Carrasco, Manuel D; Casas, David; Morales, Roberto

2016-03-01

The energy loss of argon ions in a target depends on their velocity and charge density. At the energies studied in this work, it depends mostly on the free and bound electrons in the target. Here the random-phase approximation is used for analyzing free electrons at any degeneracy. For the plasma-bound electrons, an interpolation between approximations for low and high energies is applied. The Brandt-Kitagawa (BK) model is employed to depict the projectile charge space distribution, and the stripping criterion of Kreussler et al. is used to determine its equilibrium charge state Q(eq). This latter criterion implies that the equilibrium charge state depends slightly on the electron density and temperature of the plasma. On the other hand, the effective charge Q(eff) is obtained as the ratio between the energy loss of the argon ion and that of the proton for the same plasma conditions. This effective charge Q(eff) is larger than the equilibrium charge state Q(eq) due to the incorporation of the BK charge distribution. Though our charge-state estimations are not exactly the same as the experimental values, our energy loss agrees quite well with the experiments. It is noticed that the energy loss in plasmas is higher than that in the same cold target of about, ∼42-62.5% and increases with carbon plasma ionization. This confirms the well-known enhanced plasma stopping. It is also observed that only a small part of this energy loss enhancement is due to an increase of the argon charge state, namely only ∼2.2 and 5.1%, for the partially and the fully ionized plasma, respectively. The other contribution is connected with a better energy transfer to the free electrons at plasma state than to the bound electrons at solid state of about, ∼38.8-57.4%, where higher values correspond to a fully ionized carbon plasma.

Prevalence of operator fatigue in winter maintenance operations.

Science.gov (United States)

Camden, Matthew C; Medina-Flintsch, Alejandra; Hickman, Jeffrey S; Bryce, James; Flintsch, Gerardo; Hanowski, Richard J

2018-02-02

Similar to commercial motor vehicle drivers, winter maintenance operators are likely to be at an increased risk of becoming fatigued while driving due to long, inconsistent shifts, environmental stressors, and limited opportunities for sleep. Despite this risk, there is little research concerning the prevalence of winter maintenance operator fatigue during winter emergencies. The purpose of this research was to investigate the prevalence, sources, and countermeasures of fatigue in winter maintenance operations. Questionnaires from 1043 winter maintenance operators and 453 managers were received from 29 Clear Road member states. Results confirmed that fatigue was prevalent in winter maintenance operations. Over 70% of the operators and managers believed that fatigue has a moderate to significant impact on winter maintenance operations. Approximately 75% of winter maintenance operators reported to at least sometimes drive while fatigued, and 96% of managers believed their winter maintenance operators drove while fatigued at least some of the time. Furthermore, winter maintenance operators and managers identified fatigue countermeasures and sources of fatigue related to winter maintenance equipment. However, the countermeasures believed to be the most effective at reducing fatigue during winter emergencies (i.e., naps) were underutilized. For example, winter maintenance operators reported to never use naps to eliminate fatigue. These results indicated winter maintenance operations are impacted by operator fatigue. These results support the increased need for research and effective countermeasures targeting winter maintenance operator fatigue. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fossil and Contemporary Fine Carbon Fractions at 12 Rural and Urban Sites in the United States

Energy Technology Data Exchange (ETDEWEB)

Schichtel, B; Malm, W; Bench, G; Fallon, S; McDade, C; Chow, J

2007-03-01

Fine particulate matter collected at two urban, four near-urban, and six remote sites throughout the United States were analyzed for total carbon (TC) and radiocarbon ({sup 14}C). Samples were collected at most sites for both a summer and winter season. The radiocarbon was used to partition the TC into fossil and contemporary fractions. On average, contemporary carbon composed about half of the carbon at the urban, {approx}70-97% at near-urban, and 82-100% at remote sites. At Phoenix, Arizona, and Seattle, Washington, one monitor was located within the urban center and one outside to assess the urban excess over background concentrations. During the summer the urban and rural sites had similar contemporary carbon concentrations. However, during the winter the urban sites had more than twice the contemporary carbon measured at the neighboring sites, indicating anthropogenic contributions to the contemporary carbon. The urban fossil carbon was 4-20 times larger than the neighboring rural sites for both seasons. Organic (OC) and elemental carbon (EC) from TOR analysis were available. These and the radiocarbon data were used to estimate characteristic fossil and contemporary EC/TC ratios for the winter and summer seasons. These ratios were applied to carbon data from the Interagency Monitoring of Protected Visual Environments network to estimate the fraction of contemporary carbon at mostly rural sites throughout the United States. In addition, the ratios were used to develop a semiquantitative, lower bound estimate of secondary organic carbon (SOC) contribution to fossil and contemporary carbon. SOC accounted for more than one-third of the fossil and contemporary carbon.

Loss of 'blue carbon' from coastal salt marshes following habitat disturbance.

Directory of Open Access Journals (Sweden)

Peter I Macreadie

Full Text Available Increased recognition of the global importance of salt marshes as 'blue carbon' (C sinks has led to concern that salt marshes could release large amounts of stored C into the atmosphere (as CO2 if they continue undergoing disturbance, thereby accelerating climate change. Empirical evidence of C release following salt marsh habitat loss due to disturbance is rare, yet such information is essential for inclusion of salt marshes in greenhouse gas emission reduction and offset schemes. Here we investigated the stability of salt marsh (Spartinaalterniflora sediment C levels following seagrass (Thallasiatestudinum wrack accumulation; a form of disturbance common throughout the world that removes large areas of plant biomass in salt marshes. At our study site (St Joseph Bay, Florida, USA, we recorded 296 patches (7.5 ± 2.3 m(2 mean area ± SE of vegetation loss (aged 3-12 months in a salt marsh meadow the size of a soccer field (7 275 m(2. Within these disturbed patches, levels of organic C in the subsurface zone (1-5 cm depth were ~30% lower than the surrounding undisturbed meadow. Subsequent analyses showed that the decline in subsurface C levels in disturbed patches was due to loss of below-ground plant (salt marsh biomass, which otherwise forms the main component of the long-term 'refractory' C stock. We conclude that disturbance to salt marsh habitat due to wrack accumulation can cause significant release of below-ground C; which could shift salt marshes from C sinks to C sources, depending on the intensity and scale of disturbance. This mechanism of C release is likely to increase in the future due to sea level rise; which could increase wrack production due to increasing storminess, and will facilitate delivery of wrack into salt marsh zones due to higher and more frequent inundation.

Particulate carbon in the atmosphere

International Nuclear Information System (INIS)

Surakka, J.

1992-01-01

Carbonaceous aerosols are emitted to the atmosphere in combustion processes. Carbon particles are very small and have a long residence time in the air. Black Carbon, a type of carbon aerosol, is a good label when transport of combustion emissions in the atmosphere is studied. It is also useful tool in air quality studies. Carbon particles absorb light 6.5 to 8 times stronger than any other particulate matter in the air. Their effect on decreasing visibility is about 50 %. Weather disturbances are also caused by carbon emissions e.g. in Kuwait. Carbon particles have big absorption surface and capacity to catalyze different heterogenous reactions in air. Due to their special chemical and physical properties particulate carbon is a significant air pollution specie, especially in urban air. Average particulate carbon concentration of 5.7 μg/m 2 have been measured in winter months in Helsinki

Air pollution from wood combustion. Measurements at Elverum, Norway during the winters 1981 and 1982. Luftforurensning fra vedfyring. Maalinger i Elverum, Norge vintrene 1981 og 1982

Energy Technology Data Exchange (ETDEWEB)

Ramdahl, T; Schjoldager, J; Hanssen, J E; Moeller, M

1983-01-01

Ambient sampling and anlysis of air pollutants related to wood combustion have been carried out at the town of Elverum, Norway during the winters of 1981 and 1982. Two measurement sites were selected, Elverum (within the town) and Strandfossen. The concentration of fine particles, PAH and benzene on cold days in Elverum was similar to average winter concentrations in central parts of Oslo. The concentrations in Elverum were highest during a cold period in January, second highest during a cold period in February, and lowest during a mild period between the two cold periods. The same variation was found for mutagenicity. The concentration at the site Elverum was considerably higher than at the site Stranfossen. Organic compounds characteristic of wood smoke have been found in the ambient particulate samples, especially on cold days. The concentration of total particulate carbon and carbon from biomass showed similar variations as fine particles and PAH. The average fraction of carbon from biomass relative to the total carbon concentration was 70 percent, and the fraction was highest on cold days. The average fraction corresponded quite well with an emission estimate of PAH giving an average PAH contribution from wood combustion of 60-70 percent in the winter season. The analyses of lead indicated a contribution of 3-6 percent from gasoline cars to the fine particle concentreration, which corresponds well with the emission estimate of PAH, giving an average PAH contribution from automobile traffic of 4-5 percent in the winter season. The study claerly indicates that the combustion of wood contrubutes significantly to the concentration of air pollutants in Elverum on cold days, especially fine particles, PAH and other carbonaceous compounds.

Secondary sulfate is internally mixed with sea spray aerosol and organic aerosol in the winter Arctic

Science.gov (United States)

Kirpes, Rachel M.; Bondy, Amy L.; Bonanno, Daniel; Moffet, Ryan C.; Wang, Bingbing; Laskin, Alexander; Ault, Andrew P.; Pratt, Kerri A.

2018-03-01

Few measurements of aerosol chemical composition have been made during the winter-spring transition (following polar sunrise) to constrain Arctic aerosol-cloud-climate feedbacks. Herein, we report the first measurements of individual particle chemical composition near Utqiaġvik (Barrow), Alaska, in winter (seven sample days in January and February 2014). Individual particles were analyzed by computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM-EDX, 24 847 particles), Raman microspectroscopy (300 particles), and scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS, 290 particles). Sea spray aerosol (SSA) was observed in all samples, with fresh and aged SSA comprising 99 %, by number, of 2.5-7.5 µm diameter particles, 65-95 % from 0.5-2.5 µm, and 50-60 % from 0.1-0.5 µm, indicating SSA is the dominant contributor to accumulation and coarse-mode aerosol during the winter. The aged SSA particles were characterized by reduced chlorine content with 94 %, by number, internally mixed with secondary sulfate (39 %, by number, internally mixed with both nitrate and sulfate), indicative of multiphase aging reactions during transport. There was a large number fraction (40 % of 1.0-4.0 µm diameter particles) of aged SSA during periods when particles were transported from near Prudhoe Bay, consistent with pollutant emissions from the oil fields participating in atmospheric processing of aerosol particles. Organic carbon and sulfate particles were observed in all samples and comprised 40-50 %, by number, of 0.1-0.4 µm diameter particles, indicative of Arctic haze influence. Soot was internally mixed with organic and sulfate components. All sulfate was mixed with organic carbon or SSA particles. Therefore, aerosol sources in the Alaskan Arctic and resulting aerosol chemical mixing states need to be considered when predicting aerosol climate effects, particularly cloud

Harvesting fertilized rye cover crop: simulated revenue, net energy, and drainage Nitrogen loss

Science.gov (United States)

Food and biofuel production along with global N use are expected to increase over the next few decades, which complicates the goal of reducing N loss to the environment. Including winter rye as a cover crop in corn-soybean rotations reduces N loss to drainage. A few studies suggest that harvesting r...

Retention and loss of water extractable carbon in soils: effect of clay properties.

Science.gov (United States)

Nguyen, Trung-Ta; Marschner, Petra

2014-02-01

Clay sorption is important for organic carbon (C) sequestration in soils, but little is known about the effect of different clay properties on organic C sorption and release. To investigate the effect of clay content and properties on sorption, desorption and loss of water extractable organic C (WEOC), two experiments were conducted. In experiment 1, a loamy sand alone (native) or mixed with clay isolated from a surface or subsoil (78 and 96% clay) resulting in 90, 158 and 175 g clay kg(-1) soil. These soil treatments were leached with different WEOC concentrations, and then CO2 release was measured for 28 days followed by leaching with reverse osmosis water at the end of experiment. The second experiment was conducted to determine WEOC sorption and desorption of clays isolated from the loamy sand (native), surface soil and subsoil. Addition of clays isolated from surface and subsoil to sandy loam increased WEOC sorption and reduced C leaching and cumulative respiration in percentage of total organic C and WEOC added when expressed per g soil and per g clay. Compared to clays isolated from the surface and subsoil, the native clay had higher concentrations of illite and exchangeable Ca(2+), total organic C and a higher CEC but a lower extractable Fe/Al concentration. This indicates that compared to the clay isolated from the surface and the subsoil, the native clay had fewer potential WEOC binding sites because it had lower Fe/Al content thus lower number of binding sites and the existing binding sites are already occupied native organic matter. The results of this study suggest that in the soils used here, the impact of clay on WEOC sorption and loss is dependent on its indigenous organic carbon and Fe and/or Al concentrations whereas clay mineralogy, CEC, exchangeable Ca(2+) and surface area are less important. © 2013.

Nutrient and Organic Carbon Losses, Enrichment Rate, and Cost of Water Erosion

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Ildegardis Bertol

Full Text Available ABSTRACT Soil erosion from water causes loss of nutrients and organic carbon, enriches the environment outside the erosion site, and results in costs. The no-tillage system generates increased nutrient and C content in the topsoil and, although it controls erosion, it can produce a more enriched runoff than in the conventional tillage system. This study was conducted in a Humic Cambisol in natural rainfall from 1997 to 2012 to quantify the contents and total losses of nutrients and organic C in soil runoff, and to calculate the enrichment rates and the cost of these losses. The treatments evaluated were: a soil with a crop, consisting of conventional tillage with one plowing + two harrowings (CT, minimum tillage with one chisel plowing + one harrowing (MT, and no tillage (NT; and b bare soil: one plowing + two harrowings (BS. In CT, MT, and NT, black oat, soybean, vetch, corn, turnip, and black beans were cultivated. Over the 15 years, 15.5 Mg ha-1 of limestone, 525 kg ha-1 of N (urea, 1,302 kg ha-1 of P2O5 (triple superphosphate, and 1,075 kg ha-1 of K2O (potassium chloride were used in the soil. The P, K, Ca, Mg, and organic C contents in the soil were determined and also the P, K, Ca, and Mg sediments in the runoff water. From these contents, the total losses, the enrichment rates (ER, and financial losses were calculated. The NT increased the P, K, and organic C contents in the topsoil. The nutrients and organic C content in the runoff from NT was greater than from CT, showing that NT was not a fully conservationist practice for soil. The linear model y = a + bx fit the data within the level of significance (p≤0.01 when the values of P, K, and organic C in the sediments from erosion were related to those values in the soil surface layer. The nutrient and organic C contents were higher in the sediments from erosion than in the soil where the erosion originated, generating values of ER>1 for P, K, and organic C. The value of the total losses

Air pollution from wood combustion. Measurements at Elverum, Norway during the winters 1981 and 1982. Luftforurensning fra vedfyring. Maalinger i Elverum, Norge vintrene 1981 og 1982

Energy Technology Data Exchange (ETDEWEB)

Ramdahl, T; Schjoldager, J; Hanssen, J E; Moeller, M

1983-01-01

Ambient sampling and analysis of air pollutants related to wood combustion have been carried out at the town of Elverum, Norway during the winters of 1981 and 1982. Two measurement sites were selected, Elverum (within the town) and Strandfossen. The concentration of fine particles, PAH and benzene on cold days in Elverum was similar to average winter concentrations in central parts of Oslo. The concentrations in Elverum were highest during a cold period in January, second highest during a cold period in February, and lowest during a mild period between the two cold periods. The same variation was found for mutagenicity. The concentration at the site Elverum was considerably higher than at the site Stranfossen. Organic compounds characteristic of wood smoke have been found in the ambient particulate samples, especially on cold days. The concentration of total particulate carbon and carbon from biomass showed similar variations as fine particles and PAH. The average fraction of carbon from biomass relative to the total carbon concentration was 70 percent, and the fraction was highest on cold days. The average fraction corresponded quite well with an emission estimate of PAH giving an average PAH contribution from wood combustion of 60-70 percent in the winter season. The analyses of lead indicated a contribution of 3-6 percent from gasoline cars to the fine particle concentreration.

A method for measuring losses of soil carbon by heterotrophic respiration from peat soils under oil palms

Science.gov (United States)

Farmer, Jenny; Manning, Frances; Smith, Jo; Arn Teh, Yit

2017-04-01

The effects of drainage and deforestation of South East Asian peat swamp forests for the development of oil palm plantations has received considerable attention in both mainstream media and academia, and is the source of significant discussion and debate. However, data on the long-term carbon losses from these peat soils as a result of this land use change is still limited and the methods with which to collect this data are still developing. Here we present the ongoing evolution and implementation of a method for separating autotrophic and heterotrophic respiration by sampling carbon dioxide emissions at increasing distance from palm trees. We present the limitations of the method, modelling approaches and results from our studies. In 2011 we trialled this method in Sumatra, Indonesia and collected rate measurements over a six day period in three ages of oil palm. In the four year oil palm site there were thirteen collars that had no roots present and from these the peat based carbon losses were recorded to be 0.44 g CO2 m2 hr-1 [0.34; 0.57] (equivalent to 39 t CO2 ha-1 yr-1 [30; 50]) with a mean water table depth of 0.40 m, or 63% of the measured total respiration across the plot. In the two older palm sites of six and seven years, only one collar out of 100 had no roots present, and thus a linear random effects model was developed to calculate heterotrophic emissions for different distances from the palm tree. This model suggested that heterotrophic respiration was between 37 - 59% of total respiration in the six year old plantation and 39 - 56% in the seven year old plantation. We applied this method in 2014 to a seven year old plantation, in Sarawak, Malaysia, modifying the method to include the heterotrophic contribution from beneath frond piles and weed covered areas. These results indicated peat based carbon losses to be 0.42 g CO2 m2 hr-1 [0.27;0.59] (equivalent to 37 t CO2 ha-1 yr-1 [24; 52]) at an average water table depth of 0.35 m, 47% of the measured

46 CFR 45.73 - Winter freeboard.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Winter freeboard. 45.73 Section 45.73 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES GREAT LAKES LOAD LINES Freeboards § 45.73 Winter freeboard. The minimum winter freeboard (fw) in inches is obtained by the formula: fw=f(s)+T s...

Characteristics of black carbon in snow from Laohugou No. 12 glacier on the northern Tibetan Plateau.

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Zhang, Yulan; Kang, Shichang; Li, Chaoliu; Gao, Tanguang; Cong, Zhiyuan; Sprenger, Michael; Liu, Yajun; Li, Xiaofei; Guo, Junming; Sillanpää, Mika; Wang, Kun; Chen, Jizu; Li, Yang; Sun, Shiwei

2017-12-31

Black carbon (BC) emitted from the incomplete combustion of biomass and fossil fuel impacts the climate system, cryospheric change, and human health. This study documents black carbon deposition in snow from a benchmark glacier on the northern Tibetan Plateau. Significant seasonality of BC concentrations indicates different input or post-depositional processes. BC particles deposited in snow had a mass volume median diameter slightly larger than that of black carbon particles typically found in the atmosphere. Also, unlike black carbon particles in the atmosphere, the particles deposited in snow did not exhibit highly fractal morphology by Scanning Transmission Electron Microscope. Footprint analysis indicated BC deposited on the glacier in summer originated mainly from Central Asia; in winter, the depositing air masses generally originated from Central Asia and Pakistan. Anthropogenic emissions play an important role on black carbon deposition in glacial snow, especially in winter. The mass absorption efficiency of BC in snow at 632nm exhibited significantly seasonality, with higher values in summer and lower values in winter. The information on black carbon deposition in glacial snow provided in this study could be used to help mitigate the impacts of BC on glacier melting on the northern Tibetan Plateau. Copyright © 2017 Elsevier B.V. All rights reserved.

Tropical North Atlantic ocean-atmosphere interactions synchronize forest carbon losses from hurricanes and Amazon fires

Science.gov (United States)

Chen, Yang; Randerson, James T.; Morton, Douglas C.

2015-08-01

We describe a climate mode synchronizing forest carbon losses from North and South America by analyzing time series of tropical North Atlantic sea surface temperatures (SSTs), landfall hurricanes and tropical storms, and Amazon fires during 1995-2013. Years with anomalously high tropical North Atlantic SSTs during March-June were often followed by a more active hurricane season and a larger number of satellite-detected fires in the southern Amazon during June-November. The relationship between North Atlantic tropical cyclones and southern Amazon fires (r = 0.61, p forests.

An observational study of the carbon-sink strength of East Asian subtropical evergreen forests

International Nuclear Information System (INIS)

Tan Zhenghong; Zhang Yiping; Zhang Yongjiang; Song Qinhai; Cao Kunfang; Schaefer, D A; Liu Yuhong; Liang Naishen; Hsia, Yue-Joe; Zhou Guoyi; Li Yuelin; Yan Junhua; Juang, Jehn-Yih; Chu Housen; Yu Guirui; Sun Xiaomin

2012-01-01

Relatively little is known about the effects of regional warming on the carbon cycle of subtropical evergreen forest ecosystems, which are characterized by year-round growing season and cold winters. We investigated the carbon balance in three typical East Asia subtropical evergreen forests, using eddy flux, soil respiration and leaf-level measurements. Subtropical evergreen forests maintain continuous, high rates of photosynthetic activity, even during winter cold periods. Warm summers enhance photosynthetic rates in a limited way, because overall ecosystem productivity is primarily restrained by radiation levels during the warm period. Conversely, warm climates significantly enhance the respiratory carbon efflux. The finding of lower sensitivity of photosynthesis relative to that of respiration suggests that increased temperature will weaken the carbon-sink strength of East Asia subtropical evergreen forests. (letter)

Tweet for health: using an online social network to examine temporal trends in weight loss-related posts.

Science.gov (United States)

Turner-McGrievy, Gabrielle M; Beets, Michael W

2015-06-01

Few studies have used social networking sites to track temporal trends in health-related posts, particularly around weight loss. To examine the temporal relationship of Twitter messages about weight loss over 1 year (2012). Temporal trends in #weightloss mentions and #fitness, #diet, and #health tweets which also had the word "weight" in them were examined using three a priori time periods: (1) holidays: pre-winter holidays, holidays, and post-holidays; (2) Season: winter and summer; and (3) New Year's: pre-New Year's and post-New Year's. Regarding #weightloss, there were 145 (95 % CI 79, 211) more posts/day during holidays and 143 (95 % CI 76, 209) more posts/day after holidays as compared to 480 pre-holiday posts/day; 232 (95 % CI 178, 286) more posts/day during the winter versus summer (441 posts/day); there was no difference in posts around New Year's. Examining social networks for trends in health-related posts may aid in timing interventions when individuals are more likely to be discussing weight loss.

Nitrate and dissolved organic carbon mobilization in response to soil freezing variability

Science.gov (United States)

Colin B. Fuss; Charles T. Driscoll; Peter M. Groffman; John L. Campbell; Lynn M. Christenson; Timothy J. Fahey; Melany C. Fisk; Myron J. Mitchell; Pamela H. Templer; Jorge Durán; Jennifer L. Morse

2016-01-01

Reduced snowpack and associated increases in soil freezing severity resulting from winter climate change have the potential to disrupt carbon (C) and nitrogen (N) cycling in soils. We used a natural winter climate gradient based on elevation and aspect in a northern hardwood forest to examine the effects of variability in soil freezing depth, duration, and frequency on...

Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

DEFF Research Database (Denmark)

Kindler, Reimo; Siemens, Jan; Kaiser, Klaus

2011-01-01

ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small...... solubility of CO2 in acidic forest soil solutions and large NEE. Leaching of CH4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems....

Drainage in Shallow Peatlands of Marginal Upland Landscapes: DOC Losses from High Flow Events

Science.gov (United States)

Grand-Clement, E.; Anderson, K.; Luscombe, D.; Gatis, N.; Benaud, P.; Brazier, R.

2013-12-01

) and finally headwater catchment-scales. Flow monitoring has been in place at all scales since November 2010. Flow-proportional water samples were collected during a range of events throughout winter 2011 to 2013 and analysed for Dissolved Organic Carbon (DOC) and colour, as these variables were identified as critical, both in terms of carbon cycling and for costly water treatment that currently takes place downstream. DOC fluxes were examined temporarily and spatially in relation to season, drain sizes, and magnitude/frequency of event. First results show higher DOC concentrations during rain events occurring in the summer compared to winter times, due to generally drier conditions. DOC fluxes per 24h rain events reach up to 3g/m2. Such measurements are used to evaluate annual DOC losses at the scale of the whole catchment. This will help improving our understanding of carbon losses and fluxes in streams from damaged peatlands, and further estimate the impact on the supply of ecosystem services, and the potential for improvement that can be expected following restoration.

Winter warming from large volcanic eruptions

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Robock, Alan; Mao, Jianping

1992-01-01

An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95-percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

HEAT LOSS FROM HOT WATER SUPPLY LINE IN A RESIDENTIAL BUILDING

OpenAIRE

近藤, 修平; 鉾井, 修一

2011-01-01

In order to the evaluate heat loss from hot water supply lines in a residential building, hot water demand in a house in Chiba prefecture was measured and analyzed. The following results were obtained. 1. The heat loss of the hot water supply line was about 132kJ for the shower and 110kJ for the bathtub in winter. Since the temperature difference between the inlet and outlet of the hot water supply line is small, the measured heat loss from the hot water supply line sometimes becomes negative...

Simulation of Long-Term Carbon and Nitrogen Dynamics in Grassland-Based Dairy Farming Systems to Evaluate Mitigation Strategies for Nutrient Losses.

Directory of Open Access Journals (Sweden)

Ghulam Abbas Shah

Full Text Available Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N, and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively, manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of

Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter.

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Last, Kim S; Hobbs, Laura; Berge, Jørgen; Brierley, Andrew S; Cottier, Finlo

2016-01-25

In extreme high-latitude marine environments that are without solar illumination in winter, light-mediated patterns of biological migration have historically been considered non-existent [1]. However, diel vertical migration (DVM) of zooplankton has been shown to occur even during the darkest part of the polar night, when illumination levels are exceptionally low [2, 3]. This paradox is, as yet, unexplained. Here, we present evidence of an unexpected uniform behavior across the entire Arctic, in fjord, shelf, slope and open sea, where vertical migrations of zooplankton are driven by lunar illumination. A shift from solar-day (24-hr period) to lunar-day (24.8-hr period) vertical migration takes place in winter when the moon rises above the horizon. Further, mass sinking of zooplankton from the surface waters and accumulation at a depth of ∼50 m occurs every 29.5 days in winter, coincident with the periods of full moon. Moonlight may enable predation of zooplankton by carnivorous zooplankters, fish, and birds now known to feed during the polar night [4]. Although primary production is almost nil at this time, lunar vertical migration (LVM) may facilitate monthly pulses of carbon remineralization, as they occur continuously in illuminated mesopelagic systems [5], due to community respiration of carnivorous and detritivorous zooplankton. The extent of LVM during the winter suggests that the behavior is highly conserved and adaptive and therefore needs to be considered as "baseline" zooplankton activity in a changing Arctic ocean [6-9]. VIDEO ABSTRACT. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Titan's Emergence from Winter

Science.gov (United States)

Flasar, F. Michael; Achterberg, Richard; Jennings, Donald; Schinder, Paul

2011-01-01

We summarize the changes in Titans thermal structure derived from Cassini CIRS and radio-occultation data during the transition from winter to early spring. Titan's surface, and middle atmosphere show noticeable seasonal change, whereas that in most of the troposphere is mated. This can be understood in terms of the relatively small radiative relaxation time in the middle atmosphere and much larger time scale in the troposphere. The surface exhibits seasonal change because the heat capacity in an annual skin depth is much smaller than that in the lowest scale height of the troposphere. Surface temperatures rise 1 K at raid and high latitudes in the winter northern hemisphere and cool in the southern hemisphere. Changes in in the middle atmosphere are more complicated. Temperatures in the middle stratosphere (approximately 1 mbar) increase by a few kelvin at mid northern latitudes, but those at high latitudes first increase as that region moves out of winter shadow, and then decrease. This probably results from the combined effect of increased solar heating as the suit moves higher in the sky and the decreased adiabatic warming as the sinking motions associated with the cross-equatorial meridional cell weaken. Consistent with this interpretation, the warm temperatures observed higher up at the winter polar stratopause cool significantly.

ADT fast losses MD

CERN Document Server

Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D

2013-01-01

The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...

Nutrient additions to a tropical rain forest drive substantial soil carbon dioxide losses to the atmosphere.

Science.gov (United States)

Cleveland, Cory C; Townsend, Alan R

2006-07-05

Terrestrial biosphere-atmosphere carbon dioxide (CO(2)) exchange is dominated by tropical forests, where photosynthetic carbon (C) uptake is thought to be phosphorus (P)-limited. In P-poor tropical forests, P may also limit organic matter decomposition and soil C losses. We conducted a field-fertilization experiment to show that P fertilization stimulates soil respiration in a lowland tropical rain forest in Costa Rica. In the early wet season, when soluble organic matter inputs to soil are high, P fertilization drove large increases in soil respiration. Although the P-stimulated increase in soil respiration was largely confined to the dry-to-wet season transition, the seasonal increase was sufficient to drive an 18% annual increase in CO(2) efflux from the P-fertilized plots. Nitrogen (N) fertilization caused similar responses, and the net increases in soil respiration in response to the additions of N and P approached annual soil C fluxes in mid-latitude forests. Human activities are altering natural patterns of tropical soil N and P availability by land conversion and enhanced atmospheric deposition. Although our data suggest that the mechanisms driving the observed respiratory responses to increased N and P may be different, the large CO(2) losses stimulated by N and P fertilization suggest that knowledge of such patterns and their effects on soil CO(2) efflux is critical for understanding the role of tropical forests in a rapidly changing global C cycle.

The penalty of a long, hot summer. Photosynthetic acclimation to high CO2 and continuous light in "living fossil" conifers.

Science.gov (United States)

Osborne, Colin P; Beerling, David J

2003-10-01

Deciduous forests covered the ice-free polar regions 280 to 40 million years ago under warm "greenhouse" climates and high atmospheric pCO2. Their deciduous habit is frequently interpreted as an adaptation for minimizing carbon losses during winter, but experiments with "living fossils" in a simulated warm polar environment refute this explanation. Measured carbon losses through leaf abscission of deciduous trees are significantly greater than losses through winter respiration in evergreens, yet annual rates of primary productivity are similar in all species. Here, we investigate mechanisms underlying this apparent paradox by measuring the seasonal patterns of leaf photosynthesis (A) under pCO2 enrichment in the same trees. During spring, A increased significantly in coastal redwood (Sequoia sempervirens), dawn redwood (Metasequoia glyptostroboides), and swamp cypress (Taxodium distichum) at an elevated pCO2 of 80 Pa compared with controls at 40 Pa. However, strong acclimation in Rubisco carboxylation capacity (Vc,max) completely offset the CO2 response of A in all species by the end of 6 weeks of continuous illumination in the simulated polar summer. Further measurements demonstrated the temporary nature of acclimation, with increases in Vc,max during autumn restoring the CO2 sensitivity of A. Contrary to expectations, the acclimation of Vc,max was not always accompanied by accumulation of leaf carbohydrates, but was associated with a decline in leaf nitrogen in summer, suggesting an alteration of the balance in plant sources and sinks for carbon and nitrogen. Preliminary calculations using A indicated that winter carbon losses through deciduous leaf abscission and respiration were recovered by 10 to 25 d of canopy carbon fixation during summer, thereby explaining the productivity paradox.

The Penalty of a Long, Hot Summer. Photosynthetic Acclimation to High CO2 and Continuous Light in “Living Fossil” Conifers1

Science.gov (United States)

Osborne, Colin P.; Beerling, David J.

2003-01-01

Deciduous forests covered the ice-free polar regions 280 to 40 million years ago under warm “greenhouse” climates and high atmospheric pCO2. Their deciduous habit is frequently interpreted as an adaptation for minimizing carbon losses during winter, but experiments with “living fossils” in a simulated warm polar environment refute this explanation. Measured carbon losses through leaf abscission of deciduous trees are significantly greater than losses through winter respiration in evergreens, yet annual rates of primary productivity are similar in all species. Here, we investigate mechanisms underlying this apparent paradox by measuring the seasonal patterns of leaf photosynthesis (A) under pCO2 enrichment in the same trees. During spring, A increased significantly in coastal redwood (Sequoia sempervirens), dawn redwood (Metasequoia glyptostroboides), and swamp cypress (Taxodium distichum) at an elevated pCO2 of 80 Pa compared with controls at 40 Pa. However, strong acclimation in Rubisco carboxylation capacity (Vc,max) completely offset the CO2 response of A in all species by the end of 6 weeks of continuous illumination in the simulated polar summer. Further measurements demonstrated the temporary nature of acclimation, with increases in Vc,max during autumn restoring the CO2 sensitivity of A. Contrary to expectations, the acclimation of Vc,max was not always accompanied by accumulation of leaf carbohydrates, but was associated with a decline in leaf nitrogen in summer, suggesting an alteration of the balance in plant sources and sinks for carbon and nitrogen. Preliminary calculations using A indicated that winter carbon losses through deciduous leaf abscission and respiration were recovered by 10 to 25 d of canopy carbon fixation during summer, thereby explaining the productivity paradox. PMID:12972654

Substantial N2O emission during the initial period of the wheat season due to the conversion of winter-flooded paddy to rice-wheat rotation

Science.gov (United States)

Zhou, Wei; Lin, Shan; Wu, Lei; Zhao, Jingsong; Wang, Milan; Zhu, Bo; Mo, Yongliang; Hu, Ronggui; Chadwick, Dave; Shaaban, Muhammad

2017-12-01

Winter-flooded paddy is a typical rice-based cropping system to conserve water for the next rice growing season. Conversion of winter-flooded paddy to rice-wheat rotation has been widely adopted with the development of the water conservation infrastructure and the government's encouragement of winter agriculture in China in recent decades. However, the effects of this conversion on N2O emission are still not clear. Three winter-flooded paddy fields were studied in a split-plot design. One-half of each field was converted to rice-wheat rotation (RW), and the other half remained winter-flooded as rice-fallow (RF). Each plot of RW and RF was further divided into four subplots: three subplots for conventional N fertilizer application (RW-NC and RF-NC) and one for unfertilized treatment (RW-N0 and RF-N0). Conversion of RF-NC to RW-NC increased the N2O emission up to 6.6-fold in the first year and 4.4-fold in the second year. Moreover, N2O emissions for the entire wheat season were 1.74-3.74 kg N ha-1 and 0.24-0.31 kg N ha-1 from RW-NC and RW-N0, respectively, and accounted for 78%-94% and 78%-97% of the total annual amount. N2O emitted during the first 11-21 days of the wheat season from RW-NC was 1.48-3.28 kg N ha-1 and that from RW-N0 was 0.14-0.17 kg N ha-1, which contributed to 66%-82% and 45%-71% of the total annual amount, respectively. High N2O fluxes occurred when the soil water-filled pore space (WFPS) was in the range of 68%-72% and the ratio of available carbon to nitrogen in the soil was organic carbon (DOC) explained most of the variation of the N2O fluxes compared with the other measured environmental and soil factors. These findings suggest that the conversion of winter-flooded paddy to rice-wheat rotation increased N2O emissions that could be mitigated by controlling the soil moisture and ratio of available soil carbon to nitrogen.

Depletion of rice as food of waterfowl wintering in the Mississippi Alluvial Valley

Science.gov (United States)

Greer, Danielle M.; Dugger, Bruce D.; Reinecke, Kenneth J.; Petrie, Mark J.

2009-01-01

Waterfowl habitat conservation strategies in the Mississippi Alluvial Valley (MAV) and several other wintering areas assume carrying capacity is limited by available food, and increasing food resources is an effective conservation goal. Because existing research on winter food abundance and depletion is insufficient to test this hypothesis, we used harvested rice fields as model foraging habitats to determine if waste rice seed is depleted before spring migration. We sampled rice fields (n = 39 [winter 2000-2001], n = 69 [2001-2002]) to estimate seed mass when waterfowl arrived in late autumn and departed in late winter. We also placed exclosures in subsets of fields in autumn (n = 8 [2000-2001], n = 20 [2001-2002]) and compared seed mass inside and outside exclosures in late winter to estimate rice depletion attributable to waterfowl and other processes. Finally, we used an experiment to determine if the extent of rice depletion differed among fields of varying initial abundance and if the seed mass at which waterfowl ceased foraging or abandoned fields differed from a hypothesized giving-up value of 50 kg/ha. Mean seed mass was greater in late autumn 2000 than 2001 (127.0 vs. 83.9 kg/ha; P = 0.018) but decreased more during winter 2000-2001 than 2001-2002 (91.3 vs. 55.7 kg/ha) and did not differ at the end of winter (35.8 vs. 28.3 kg/ha; P = 0.651). Assuming equal loss to deterioration inside and outside exclosures, we estimated waterfowl consumed 61.3 kg/ha (48.3%) of rice present in late autumn 2000 and 21.1 kg/ha (25.1%) in 2001. When we manipulated late-autumn rice abundance, mean giving-up mass of rice seed was similar among treatments (48.7 kg/ha; P = 0.205) and did not differ from 50 kg/ha (P = 0.726). We integrated results by constructing scenarios in which waterfowl consumed rice at different times in winter, consumption and deterioration were competing risks, and consumption occurred only above 50 kg/ha. Results indicated waterfowl likely consumed

36 CFR 1002.19 - Winter activities.

Science.gov (United States)

2010-07-01

... RECREATION § 1002.19 Winter activities. (a) Skiing, snowshoeing, ice skating, sledding, innertubing, tobogganing and similar winter sports are prohibited on Presidio Trust roads and in parking areas open to...

Oxidation kinetics and mechanisms of carbon/carbon composites and their components in water vapour at high temperatures

International Nuclear Information System (INIS)

Qin, Fei; Peng, Li-na; He, Guo-qiang; Li, Jiang; Yan, Yong

2015-01-01

Highlights: • 4D-C/C composite was fabricated using carbon fibre and coal tar pitch. • The rate of mass loss and oxidation kinetics parameters of fibres-H 2 O and matrix-H 2 O are obtained. • The rate of mass loss and oxidation kinetics parameters of C/C–H 2 O are obtained. • Oxidation rate of the fibre bundle is greater than the oxidation rate of the matrix. - Abstract: Thermogravimetric analysis and scanning electron microscopy were used to study the oxidation kinetics of four-direction carbon/carbon composites and their components (fibres and matrices) in a H 2 O–Ar atmosphere at high temperatures. The oxidation processes were restricted to reaction-limited oxidation. The rate of mass loss was estimated for the four-direction carbon/carbon composites and their components at high temperature. The pressure exponent for the reaction of the carbon/carbon composites with H 2 O was 0.59, and the pre-exponential factor and activation energy for the reactions of H 2 O with the carbon/carbon composites, carbon fibres and matrices were determined

Present and Future Carbon Balance of Russia's Northern Ecosystems. Final report

Energy Technology Data Exchange (ETDEWEB)

Chapin, F. Stuart III; Zimov, Sergei A.

2000-08-28

Recent increases in the seasonal amplitude of atmospheric CO{sub 2} at high latitudes suggest a widespread biospheric response to high-latitude warming. We have shown that the seasonal amplitude of net ecosystem carbon exchange by northern Siberian ecosystems is greater in disturbed than undisturbed sites, due to increased summer influx and increased winter efflux. Net carbon gain in summer and respiration in winter were greater in a cool than in a warm year, especially in disturbed sites and did not differ between high-arctic and treeline sites, suggesting that high-latitude warming, if it occurred, would have little effect or would reduce seasonal amplitude of carbon exchange. We suggest that increased disturbance contributes significantly to the amplified seasonal cycle of atmospheric CO{sub 2} at high latitudes.

Elevated carbon dioxide: impacts on soil and plant water relations

National Research Council Canada - National Science Library

Kirkham, M. B

2011-01-01

.... Focusing on this critical issue, Elevated Carbon Dioxide: Impacts on Soil and Plant Water Relations presents research conducted on field-grown sorghum, winter wheat, and rangeland plants under elevated CO2...

Thrips (Thysanoptera: Thripidae) mitigation in seedling cotton using strip tillage and winter cover crops.

Science.gov (United States)

Toews, Michael D; Tubbs, R Scott; Wann, Dylan Q; Sullivan, Dana

2010-10-01

Thrips are the most consistent insect pests of seedling cotton in the southeastern United States, where symptoms can range from leaf curling to stand loss. In a 2 year study, thrips adults and immatures were sampled at 14, 21 and 28 days after planting on cotton planted with a thiamethoxam seed treatment in concert with crimson clover, wheat or rye winter cover crops and conventional or strip tillage to investigate potential differences in thrips infestations. Densities of adult thrips, primarily Frankliniella fusca (Hinds), peaked on the first sampling date, whereas immature densities peaked on the second sampling date. Regardless of winter cover crop, plots that received strip tillage experienced significantly fewer thrips at each sampling interval. In addition, assessment of percentage ground cover 42 days after planting showed that there was more than twice as much ground cover in the strip-tilled plots compared with conventionally tilled plots. Correlation analyses showed that increased ground cover was inversely related to thrips densities that occurred on all three sampling dates in 2008 and the final sampling date in 2009. Growers who utilize strip tillage and a winter cover crop can utilize seed treatments for mitigation of early-season thrips infestation.

Characteristics of Soil and Organic Carbon Loss Induced by Water Erosion on the Loess Plateau in China.

Science.gov (United States)

Li, Zhongwu; Nie, Xiaodong; Chang, Xiaofeng; Liu, Lin; Sun, Liying

2016-01-01

Soil erosion has been a common environmental problem in the Loess Plateau in China. This study aims to better understand the losses of soil organic carbon (SOC) induced by water erosion. Laboratory-simulated rainfall experiments were conducted to investigate the characteristics of SOC loss induced by water erosion. The applied treatments included two rainfall intensities (90 and 120 mm h-1), four slope gradients (10°, 15°, 20°, and 25°), and two typical soil types- silty clay loam and silty loam. Results showed that the sediment OC enrichment ratios (ERoc) in all the events were relative stable with values ranged from 0.85 to1.21 and 0.64 to 1.52 and mean values of 0.98 and 1.01 for silty clay loam and silty loam, respectively. Similar to the ERoc, the proportions of different sized particles in sediment showed tiny variations during erosion processes. No significant correlation was observed between ERoc values and the proportions of sediment particles. Slope, rainfall intensity and soil type almost had no impact on ERoc. These results indicate that the transportation of SOC during erosion processes was nonselective. While the mean SOC loss rates for the events of silty clay loam and silty loam were 0.30 and 0.08 g m-2 min-1, respectively. Greater differences in SOC loss rates were found in events among different soil types. Meanwhile, significant correlations between SOC loss and soil loss for all the events were observed. These results indicated that the amount of SOC loss was influenced primarily by soil loss and the SOC content of the original soil. Erosion pattern and original SOC content are two main factors by which different soils can influence SOC loss. It seems that soil type has a greater impact on SOC loss than rainfall characteristics on the Loess Plateau of China. However, more kinds of soils should be further studied due to the special formation processes in the Loess Plateau.

Examining winter visitor use in Yellowstone National Park

Science.gov (United States)

Mae A. Davenport; Wayne A. Freimund; William T. Borrie; Robert E. Manning; William A. Valliere; Benjamin Wang

2000-01-01

This research was designed to assist the managers of Yellowstone National Park (YNP) in their decision making about winter visitation. The focus of this report is on winter use patterns and winter visitor preferences. It is the author’s hope that this information will benefit both the quality of winter experiences and the stewardship of the park resources. This report...

An appraisal of Indonesia's immense peat carbon stock using national peatland maps: uncertainties and potential losses from conversion.

Science.gov (United States)

Warren, Matthew; Hergoualc'h, Kristell; Kauffman, J Boone; Murdiyarso, Daniel; Kolka, Randall

2017-12-01

A large proportion of the world's tropical peatlands occur in Indonesia where rapid conversion and associated losses of carbon, biodiversity and ecosystem services have brought peatland management to the forefront of Indonesia's climate mitigation efforts. We evaluated peat volume from two commonly referenced maps of peat distribution and depth published by Wetlands International (WI) and the Indonesian Ministry of Agriculture (MoA), and used regionally specific values of carbon density to calculate carbon stocks. Peatland extent and volume published in the MoA maps are lower than those in the WI maps, resulting in lower estimates of carbon storage. We estimate Indonesia's total peat carbon store to be within 13.6 GtC (the low MoA map estimate) and 40.5 GtC (the high WI map estimate) with a best estimate of 28.1 GtC: the midpoint of medium carbon stock estimates derived from WI (30.8 GtC) and MoA (25.3 GtC) maps. This estimate is about half of previous assessments which used an assumed average value of peat thickness for all Indonesian peatlands, and revises the current global tropical peat carbon pool to 75 GtC. Yet, these results do not diminish the significance of Indonesia's peatlands, which store an estimated 30% more carbon than the biomass of all Indonesian forests. The largest discrepancy between maps is for the Papua province, which accounts for 62-71% of the overall differences in peat area, volume and carbon storage. According to the MoA map, 80% of Indonesian peatlands are peatlands is conservatively estimated to be 10.6 GtC, equivalent to 42% of Indonesia's total peat carbon and about 12 years of global emissions from land use change at current rates. Considering the high uncertainties in peatland extent, volume and carbon storage revealed in this assessment of current maps, a systematic revision of Indonesia's peat maps to produce a single geospatial reference that is universally accepted would improve national peat carbon storage estimates and

Winter Dew Harvest in Mexico City

Directory of Open Access Journals (Sweden)

Arias-Torres Jorge Ernesto

2015-12-01

Full Text Available This study presents experimental and theoretical results of winter dew harvest in México City in terms of condensation rate. A simplified theoretical model based on a steady-state energy balance on a radiator-condenser was fitted, as a function of the ambient temperature, the relative humidity and the wind velocity. A glass sheet and aluminum sheet white-painted were used as samples over the outdoor experiments. A good correlation was obtained between the theoretical and experimental data. The experimental results show that there was condensation in 68% of the winter nights on both condensers. The total winter condensed mass was 2977 g/m2 and 2888 g/m2 on the glass sheet and aluminum sheet white-painted, respectively. Thus, the condensed mass on the glass was only 3% higher than that on the painted surface. The maximum nightly dew harvests occurred during December, which linearly reduced from 50 g/m2 night to 22 g/m2 night as the winter months went by. The condensation occurred from 1:00 a.m. to 9:00 a.m., with maximum condensation rates between 6:00 a.m. and 7:00 a.m. The dew harvest can provide a partial alternative to the winter water shortage in certain locations with similar climates to the winter in Mexico City, as long as pollution is not significant.

Composition and sources of carbonaceous aerosols in Northern Europe during winter

Science.gov (United States)

Glasius, M.; Hansen, A. M. K.; Claeys, M.; Henzing, J. S.; Jedynska, A. D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J. K.; Spindler, G.; Stenström, K. E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K. E.

2018-01-01

Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The Netherlands; Melpitz, Germany) during winter 2013. Analysis of 14C and a set of molecular tracers were used to constrain the sources of EC and OC. During the four-week campaign, most sites (in particular those in Germany and The Netherlands) were affected by an episode during the first two weeks with high concentrations of aerosol, as continental air masses were transported westward. The analysis results showed a clear, increasing north to south gradient for most molecular tracers. Total carbon (TC = OC + EC) at Birkenes showed an average concentration of 0.5 ± 0.3 μg C m-3, whereas the average concentration at Melpitz was 6.0 ± 4.3 μg C m-3. One weekly mean TC concentration as high as 11 μg C m-3 was observed at Melpitz. Average levoglucosan concentrations varied by an order of magnitude from 25 ± 13 ng m-3 (Birkenes) to 249 ± 13 ng m-3 (Melpitz), while concentrations of tracers of fungal spores (arabitol and mannitol) and vegetative debris (cellulose) were very low, showing a minor influence of primary biological aerosol particles during the North European winter. The fraction of modern carbon generally varied from 0.57 (Melpitz) to 0.91 (Birkenes), showing an opposite trend compared to the molecular tracers and TC. Total concentrations of 10 biogenic and anthropogenic carboxylic acids, mainly of secondary origin, were 4-53 ng m-3, with the lowest concentrations observed at Birkenes and the highest at Melpitz. However, the highest relative concentrations of carboxylic acids (normalized to TC) were observed at the most northern sites. Levels of organosulphates and nitrooxy organosulphates varied more than two orders of magnitude, from 2 to 414 ng m-3, between

Hellsgate Big Game Winter Range Wildlife Mitigation Project : Annual Report 2008.

Energy Technology Data Exchange (ETDEWEB)

Whitney, Richard P.; Berger, Matthew T.; Rushing, Samuel; Peone, Cory

2009-01-01

The Hellsgate Big Game Winter Range Wildlife Mitigation Project (Hellsgate Project) was proposed by the Confederated Tribes of the Colville Reservation (CTCR) as partial mitigation for hydropower's share of the wildlife losses resulting from Chief Joseph and Grand Coulee Dams. At present, the Hellsgate Project protects and manages 57,418 acres (approximately 90 miles2) for the biological requirements of managed wildlife species; most are located on or near the Columbia River (Lake Rufus Woods and Lake Roosevelt) and surrounded by Tribal land. To date we have acquired about 34,597 habitat units (HUs) towards a total 35,819 HUs lost from original inundation due to hydropower development. In addition to the remaining 1,237 HUs left unmitigated, 600 HUs from the Washington Department of Fish and Wildlife that were traded to the Colville Tribes and 10 secure nesting islands are also yet to be mitigated. This annual report for 2008 describes the management activities of the Hellsgate Big Game Winter Range Wildlife Mitigation Project (Hellsgate Project) during the past year.

Leadership in American Indian Communities: Winter Lessons

Science.gov (United States)

Metoyer, Cheryl A.

2010-01-01

Winter lessons, or stories told in the winter, were one of the ways in which tribal elders instructed and directed young men and women in the proper ways to assume leadership responsibilities. Winter lessons stressed the appropriate relationship between the leader and the community. The intent was to remember the power and purpose of that…

Tracing organic matter sources of estuarine tidal flat nematodes with stable carbon isotopes

NARCIS (Netherlands)

Moens, T.; Luyten, C.; Middelburg, J.J.; Herman, P.M.J.; Vincx, M.

2002-01-01

The present study explores the use of stable carbon isotopes to trace organic matter sources of intertidal nematodes in the Schelde estuary (SW Netherlands). Stable carbon isotope signatures of nematodes from a saltmarsh and 4 tidal flat stations were determined in spring and winter situations, and

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

Nitrate Leaching from Winter Cereal Cover Crops Using Undisturbed Soil-Column Lysimeters.

Science.gov (United States)

Meisinger, John J; Ricigliano, Kristin A

2017-05-01

Cover crops are important management practices for reducing nitrogen (N) leaching, especially in the Chesapeake Bay watershed, which is under total maximum daily load (TMDL) restraints. Winter cereals are common cool-season crops in the Bay watershed, but studies have not directly compared nitrate-N (NO-N) leaching losses from these species. A 3-yr cover crop lysimeter study was conducted in Beltsville, MD, to directly compare NO-N leaching from a commonly grown cultivar of barley ( L.), rye ( L.), and wheat ( L.), along with a no-cover control, using eight tension-drained undisturbed soil column lysimeters in a completely randomized design with two replicates. The lysimeters were configured to exclude runoff and to estimate NO-N leaching and flow-weighted NO-N concentration (FWNC). The temporal pattern of NO-N leaching showed a consistent highly significant ( leaching with cover crops compared with no cover but showed only small and periodically significant ( leaching was more affected by the quantity of establishment-season (mid-October to mid-December) precipitation than by cover crop species. For example, compared with no cover, winter cereal covers reduced NO-N leaching 95% in a dry year and 50% in wet years, with corresponding reductions in FWNC of 92 and 43%, respectively. These results are important for scientists, nutrient managers, and policymakers because they directly compare NO-N leaching from winter cereal covers and expand knowledge for developing management practices for winter cereals that can improve water quality and increase N efficiency in cropping systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Uptake of water via branches helps timberline conifers refill embolized xylem in late winter.

Science.gov (United States)

Mayr, Stefan; Schmid, Peter; Laur, Joan; Rosner, Sabine; Charra-Vaskou, Katline; Dämon, Birgit; Hacke, Uwe G

2014-04-01

Xylem embolism is a limiting factor for woody species worldwide. Conifers at the alpine timberline are exposed to drought and freeze-thaw stress during winter, which induce potentially lethal embolism. Previous studies indicated that timberline trees survive by xylem refilling. In this study on Picea abies, refilling was monitored during winter and spring seasons and analyzed in the laboratory and in situ experiments, based on hydraulic, anatomical, and histochemical methods. Refilling started in late winter, when the soil was frozen and soil water not available for the trees. Xylem embolism caused up to 86.2% ± 3.1% loss of conductivity and was correlated with the ratio of closed pits. Refilling of xylem as well as recovery in shoot conductance started in February and corresponded with starch accumulation in secondary phloem and in the mesophyll of needles, where we also observed increasing aquaporin densities in the phloem and endodermis. This indicates that active, cellular processes play a role for refilling even under winter conditions. As demonstrated by our experiments, water for refilling was thereby taken up via the branches, likely by foliar water uptake. Our results suggest that refilling is based on water shifts to embolized tracheids via intact xylem, phloem, and parenchyma, whereby aquaporins reduce resistances along the symplastic pathway and aspirated pits facilitate isolation of refilling tracheids. Refilling must be taken into account as a key process in plant hydraulics and in estimating future effects of climate change on forests and alpine tree ecosystems.

Habitat preferences and conservation threats to Black-necked Cranes wintering in Bhutan.

Science.gov (United States)

Namgay, Rinchen; Wangchuk, Sangay

2016-01-01

Black-necked Crane (Grus nigricollis) is a vulnerable Red list species whose populations are declining. However, little is known about Black-necked Cranes' habitat requirements or the causes of their population decline. We identified Black-necked Cranes' winter roost and foraging preferences of Black-necked Cranes in Bhutan during the winter of 2013-2014. Black-necked Cranes' roosts were recorded using Garmin GPSmap 60CSx, while foraging preferences and threats to the birds were identified based on a survey of household heads (n = 107) residing within a 3 km radius of roost sites. We grouped the threats identified by the communities into four major categories, viz. biological, social, political and natural threats based on the relevance. Of the four major threats, communities residing within the roosting and foraging habitat of the Black-necked Crane reported biological threat as major. Biological threats as reported by communities include loss of habitat, food shortage and competition from other animals. We recommend the present roosting areas be designated as part of the conservation areas for Black-necked Crane wintering in Bumthang district. In addition to preserving these areas, government should also encourage farming in foraging habitats of Black-necked Crane, because they mainly feed on barley, wheat, paddy, potatoes and buckwheat, besides roots, tubers and insects in the wetlands.

Circumpolar assessment of rhizosphere priming shows limited increase in carbon loss estimates for permafrost soils but large regional variability

Science.gov (United States)

Wild, B.; Keuper, F.; Kummu, M.; Beer, C.; Blume-Werry, G.; Fontaine, S.; Gavazov, K.; Gentsch, N.; Guggenberger, G.; Hugelius, G.; Jalava, M.; Koven, C.; Krab, E. J.; Kuhry, P.; Monteux, S.; Richter, A.; Shazhad, T.; Dorrepaal, E.

2017-12-01

Predictions of soil organic carbon (SOC) losses in the northern circumpolar permafrost area converge around 15% (± 3% standard error) of the initial C pool by 2100 under the RCP 8.5 warming scenario. Yet, none of these estimates consider plant-soil interactions such as the rhizosphere priming effect (RPE). While laboratory experiments have shown that the input of plant-derived compounds can stimulate SOC losses by up to 1200%, the magnitude of RPE in natural ecosystems is unknown and no methods for upscaling exist so far. We here present the first spatial and depth explicit RPE model that allows estimates of RPE on a large scale (PrimeSCale). We combine available spatial data (SOC, C/N, GPP, ALT and ecosystem type) and new ecological insights to assess the importance of the RPE at the circumpolar scale. We use a positive saturating relationship between the RPE and belowground C allocation and two ALT-dependent rooting-depth distribution functions (for tundra and boreal forest) to proportionally assign belowground C allocation and RPE to individual soil depth increments. The model permits to take into account reasonable limiting factors on additional SOC losses by RPE including interactions between spatial and/or depth variation in GPP, plant root density, SOC stocks and ALT. We estimate potential RPE-induced SOC losses at 9.7 Pg C (5 - 95% CI: 1.5 - 23.2 Pg C) by 2100 (RCP 8.5). This corresponds to an increase of the current permafrost SOC-loss estimate from 15% of the initial C pool to about 16%. If we apply an additional molar C/N threshold of 20 to account for microbial C limitation as a requirement for the RPE, SOC losses by RPE are further reduced to 6.5 Pg C (5 - 95% CI: 1.0 - 16.8 Pg C) by 2100 (RCP 8.5). Although our results show that current estimates of permafrost soil C losses are robust without taking into account the RPE, our model also highlights high-RPE risk in Siberian lowland areas and Alaska north of the Brooks Range. The small overall impact of

Losses of soil carbon by converting tropical forest to plantations: erosion and decomposition estimated by δ(13) C.

Science.gov (United States)

Guillaume, Thomas; Damris, Muhammad; Kuzyakov, Yakov

2015-09-01

Indonesia lost more tropical forest than all of Brazil in 2012, mainly driven by the rubber, oil palm, and timber industries. Nonetheless, the effects of converting forest to oil palm and rubber plantations on soil organic carbon (SOC) stocks remain unclear. We analyzed SOC losses after lowland rainforest conversion to oil palm, intensive rubber, and extensive rubber plantations in Jambi Province on Sumatra Island. The focus was on two processes: (1) erosion and (2) decomposition of soil organic matter. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced up to 70% and 62%, respectively. The decrease was lower under extensive rubber plantations (41%). On average, converting forest to plantations led to a loss of 10 Mg C ha(-1) after about 15 years of conversion. The C content in the subsoil was similar under the forest and the plantations. We therefore assumed that a shift to higher δ(13) C values in plantation subsoil corresponds to the losses from the upper soil layer by erosion. Erosion was estimated by comparing the δ(13) C profiles in the soils under forest and under plantations. The estimated erosion was the strongest in oil palm (35 ± 8 cm) and rubber (33 ± 10 cm) plantations. The (13) C enrichment of SOC used as a proxy of its turnover indicates a decrease of SOC decomposition rate in the Ah horizon under oil palm plantations after forest conversion. Nonetheless, based on the lack of C input from litter, we expect further losses of SOC in oil palm plantations, which are a less sustainable land use compared to rubber plantations. We conclude that δ(13) C depth profiles may be a powerful tool to disentangle soil erosion and SOC mineralization after the conversion of natural ecosystems conversion to intensive plantations when soils show gradual increase of δ(13) C values with depth. © 2015 The Authors. Global Change Biology published by John Wiley & Sons Ltd.

Barriers to wheelchair use in the winter.

Science.gov (United States)

Ripat, Jacquie D; Brown, Cara L; Ethans, Karen D

2015-06-01

To test the hypothesis that challenges to community participation posed by winter weather are greater for individuals who use scooters, manual and power wheelchairs (wheeled mobility devices [WMDs]) than for the general ambulatory population, and to determine what WMD users identify as the most salient environmental barriers to community participation during the winter. Cross-sectional survey organized around 5 environmental domains: technological, natural, physical, social/attitudinal, and policy. Urban community in Canada. Convenience sample of WMD users or their proxy (N=99). Not applicable. Not applicable. Forty-two percent identified reduced outing frequency in winter months, associated with increased age (χ(3)=6.4, P=.04), lack of access to family/friends for transportation (χ(2)=8.1, P=.04), and primary type of WMD used in the winter (scooter χ(2)=8.8, P=.003). Most reported tires/casters becoming stuck in the snow (95%) or slipping on the ice (91%), difficulty ascending inclines/ramps (92%), and cold hands while using controls or pushing rims (85%); fewer identified frozen wheelchair/scooter batteries, seat cushions/backrests, or electronics. Sidewalks/roads were reported to be problematic by 99%. Eighty percent reported needing additional help in the winter. Limited community access in winter led to a sense of loneliness/isolation, and fear/anxiety related to safety. Respondents identified policies that limited participation during winter. People who use WMDs decrease their community participation in cold weather because of multiple environmental barriers. Clinicians, researchers, and policymakers can take a multidimensional approach to mitigate these barriers in order to enhance community participation by WMD users in winter. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

AGA predicts winter jump in residential gas price

International Nuclear Information System (INIS)

Anon.

1992-01-01

The American Gas Association predicts the average heating bill for residential gas consumers could increase by as much as 18% this winter. AGA Pres. Mike Baly said, Last year's winter was warmer than normal. If the 1992-93 winter is similar, AGA projects that residential natural gas heating bills will go up about 6%. If we see a return to normal winter weather, our projection show the average bill could rise by almost 18%

Annual carbon balance of a peatland 10 yr following restoration

Directory of Open Access Journals (Sweden)

M. Strack

2013-05-01

Full Text Available Undisturbed peatlands represent long-term net sinks of carbon; however, peat extraction converts these systems into large and persistent sources of greenhouse gases. Although rewetting and restoration following peat extraction have taken place over the last several decades, very few studies have investigated the longer term impact of this restoration on peatland carbon balance. We determined the annual carbon balance of a former horticulturally-extracted peatland restored 10 yr prior to the study and compared these values to the carbon balance measured at neighboring unrestored and natural sites. Carbon dioxide (CO2 and methane (CH4 fluxes were measured using the chamber technique biweekly during the growing season from May to October 2010 and three times over the winter period. Dissolved organic carbon (DOC export was measured from remnant ditches in the unrestored and restored sites. During the growing season the restored site had greater uptake of CO2 than the natural site when photon flux density was greater than 1000 μmol m−2 s−1, while the unrestored site remained a source of CO2. Ecosystem respiration was similar between natural and restored sites, which were both significantly lower than the unrestored site. Methane flux remained low at the restored site except from open water pools, created as part of restoration, and remnant ditches. Export of DOC during the growing season was 5.0 and 28.8 g m−2 from the restored and unrestored sites, respectively. Due to dry conditions during the study year all sites acted as net carbon sources with annual balance of the natural, restored and unrestored sites of 250.7, 148.0 and 546.6 g C m−2, respectively. Although hydrological conditions and vegetation community at the restored site remained intermediate between natural and unrestored conditions, peatland restoration resulted in a large reduction in annual carbon loss from the system resulting in a carbon balance more similar to a natural

The effect of fire and permafrost interactions on soil carbon accumulation in an upland black spruce ecosystem of interior Alaska: Implications for post-thaw carbon loss

Science.gov (United States)

O'Donnell, J. A.; Harden, J.W.; McGuire, A.D.; Kanevskiy, M.Z.; Jorgenson, M.T.; Xu, X.

2011-01-01

High-latitude regions store large amounts of organic carbon (OC) in active-layer soils and permafrost, accounting for nearly half of the global belowground OC pool. In the boreal region, recent warming has promoted changes in the fire regime, which may exacerbate rates of permafrost thaw and alter soil OC dynamics in both organic and mineral soil. We examined how interactions between fire and permafrost govern rates of soil OC accumulation in organic horizons, mineral soil of the active layer, and near-surface permafrost in a black spruce ecosystem of interior Alaska. To estimate OC accumulation rates, we used chronosequence, radiocarbon, and modeling approaches. We also developed a simple model to track long-term changes in soil OC stocks over past fire cycles and to evaluate the response of OC stocks to future changes in the fire regime. Our chronosequence and radiocarbon data indicate that OC turnover varies with soil depth, with fastest turnover occurring in shallow organic horizons (~60 years) and slowest turnover in near-surface permafrost (>3000 years). Modeling analysis indicates that OC accumulation in organic horizons was strongly governed by carbon losses via combustion and burial of charred remains in deep organic horizons. OC accumulation in mineral soil was influenced by active layer depth, which determined the proportion of mineral OC in a thawed or frozen state and thus, determined loss rates via decomposition. Our model results suggest that future changes in fire regime will result in substantial reductions in OC stocks, largely from the deep organic horizon. Additional OC losses will result from fire-induced thawing of near-surface permafrost. From these findings, we conclude that the vulnerability of deep OC stocks to future warming is closely linked to the sensitivity of permafrost to wildfire disturbance. ?? 2010 Blackwell Publishing Ltd.

Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer

Science.gov (United States)

Whiteman, John P.; Harlow, Henry J.; Durner, George M.; Regehr, Eric V.; Rourke, Bryan C.; Robles, Manuel; Amstrup, Steven C.; Ben-David, Merav

2017-01-01

When reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. Polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). We investigated muscle atrophy in samples of biceps femoris collected from free-ranging polar bears in the Southern Beaufort Sea (SBS) throughout their annual cycle. Atrophy was most pronounced in April–May as a result of food deprivation during the previous winter, with muscles exhibiting reduced protein concentration, increased water content, and lower creatine kinase mRNA. These animals increased feeding and activity in spring (when seal prey becomes more available), initiating a period of muscle recovery. During the following ice melt of late summer, ~30% of SBS bears abandon retreating sea ice for land; in August, these ‘shore’ bears exhibited no muscle atrophy, indicating that they had fully recovered from winter food deprivation. These individuals subsequently scavenged whale carcasses deposited by humans and by October, had retained good muscle condition. In contrast, ~70% of SBS bears follow the ice north in late summer, into deep water with less prey. These ‘ice’ bears fast; by October, they exhibited muscle protein loss and rapid changes in myosin heavy-chain isoforms in response to reduced activity. These findings indicate that, unlike other bears during winter hibernation, polar bears without food in summer cannot mitigate atrophy. Consequently, prolonged summer fasting resulting from climate change-induced ice loss creates a risk of greater muscle atrophy and reduced abilities to travel and hunt.

Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer

Science.gov (United States)

Harlow, Henry J.; Durner, George M.; Regehr, Eric V.; Rourke, Bryan C.; Robles, Manuel; Amstrup, Steven C.; Ben-David, Merav

2017-01-01

Abstract When reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. Polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). We investigated muscle atrophy in samples of biceps femoris collected from free-ranging polar bears in the Southern Beaufort Sea (SBS) throughout their annual cycle. Atrophy was most pronounced in April–May as a result of food deprivation during the previous winter, with muscles exhibiting reduced protein concentration, increased water content, and lower creatine kinase mRNA. These animals increased feeding and activity in spring (when seal prey becomes more available), initiating a period of muscle recovery. During the following ice melt of late summer, ~30% of SBS bears abandon retreating sea ice for land; in August, these ‘shore’ bears exhibited no muscle atrophy, indicating that they had fully recovered from winter food deprivation. These individuals subsequently scavenged whale carcasses deposited by humans and by October, had retained good muscle condition. In contrast, ~70% of SBS bears follow the ice north in late summer, into deep water with less prey. These ‘ice’ bears fast; by October, they exhibited muscle protein loss and rapid changes in myosin heavy-chain isoforms in response to reduced activity. These findings indicate that, unlike other bears during winter hibernation, polar bears without food in summer cannot mitigate atrophy. Consequently, prolonged summer fasting resulting from climate change-induced ice loss creates a risk of greater muscle atrophy and reduced abilities to travel and hunt. PMID:28835844

Polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer.

Science.gov (United States)

Whiteman, John P; Harlow, Henry J; Durner, George M; Regehr, Eric V; Rourke, Bryan C; Robles, Manuel; Amstrup, Steven C; Ben-David, Merav

2017-01-01

When reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. Polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). We investigated muscle atrophy in samples of biceps femoris collected from free-ranging polar bears in the Southern Beaufort Sea (SBS) throughout their annual cycle. Atrophy was most pronounced in April-May as a result of food deprivation during the previous winter, with muscles exhibiting reduced protein concentration, increased water content, and lower creatine kinase mRNA. These animals increased feeding and activity in spring (when seal prey becomes more available), initiating a period of muscle recovery. During the following ice melt of late summer, ~30% of SBS bears abandon retreating sea ice for land; in August, these 'shore' bears exhibited no muscle atrophy, indicating that they had fully recovered from winter food deprivation. These individuals subsequently scavenged whale carcasses deposited by humans and by October, had retained good muscle condition. In contrast, ~70% of SBS bears follow the ice north in late summer, into deep water with less prey. These 'ice' bears fast; by October, they exhibited muscle protein loss and rapid changes in myosin heavy-chain isoforms in response to reduced activity. These findings indicate that, unlike other bears during winter hibernation, polar bears without food in summer cannot mitigate atrophy. Consequently, prolonged summer fasting resulting from climate change-induced ice loss creates a risk of greater muscle atrophy and reduced abilities to travel and hunt.

Root development of fodder radish and winter wheat before winter in relation to uptake of nitrogen

DEFF Research Database (Denmark)

Wahlström, Ellen Margrethe; Hansen, Elly Møller; Mandel, A.

2015-01-01

occurred. Quantitative data is missing on N leaching of a catch crop compared to a winter cereal in a conventional cereal-based cropping system. The aim of the study was to investigate whether fodder radish (Raphanus sativus L.) (FR) would be more efficient than winter wheat (Triticum aestivum L.) (WW...

The meaning of nuclear winter

International Nuclear Information System (INIS)

Geiger, H.J.

1987-01-01

In this paper the author reviews the history and origins of the basic ideas underlying nuclear winter; and findings and predictions of several groups regarding this topic. The author reviews some of the further developments and scientific analyses regarding nuclear winter since the initial announcements of 1983, touching on some of the revisions and controversies and trying to indicate the current status of the field

Winter climate limits subantarctic low forest growth and establishment.

Science.gov (United States)

Harsch, Melanie A; McGlone, Matt S; Wilmshurst, Janet M

2014-01-01

Campbell Island, an isolated island 600 km south of New Zealand mainland (52 °S, 169 °E) is oceanic (Conrad Index of Continentality  =  -5) with small differences between mean summer and winter temperatures. Previous work established the unexpected result that a mean annual climate warming of c. 0.6 °C since the 1940's has not led to upward movement of the forest limit. Here we explore the relative importance of summer and winter climatic conditions on growth and age-class structure of the treeline forming species, Dracophyllum longifolium and Dracophyllum scoparium over the second half of the 20th century. The relationship between climate and growth and establishment were evaluated using standard dendroecological methods and local climate data from a meteorological station on the island. Growth and establishment were correlated against climate variables and further evaluated within hierarchical regression models to take into account the effect of plot level variables. Winter climatic conditions exerted a greater effect on growth and establishment than summer climatic conditions. Establishment is maximized under warm (mean winter temperatures >7 °C), dry winters (total winter precipitation <400 mm). Growth, on the other hand, is adversely affected by wide winter temperature ranges and increased rainfall. The contrasting effect of winter warmth on growth and establishment suggests that winter temperature affects growth and establishment through differing mechanisms. We propose that milder winters enhance survival of seedlings and, therefore, recruitment, but increases metabolic stress on established plants, resulting in lower growth rates. Future winter warming may therefore have complex effects on plant growth and establishment globally.

Sage-grouse habitat selection during winter in Alberta

Science.gov (United States)

Carpenter, Jennifer L.; Aldridge, Cameron L.; Boyce, Mark S.

2010-01-01

Greater sage-grouse (Centrocercus urophasianus) are dependent on sagebrush (Artemisia spp.) for food and shelter during winter, yet few studies have assessed winter habitat selection, particularly at scales applicable to conservation planning. Small changes to availability of winter habitats have caused drastic reductions in some sage-grouse populations. We modeled winter habitat selection by sage-grouse in Alberta, Canada, by using a resource selection function. Our purpose was to 1) generate a robust winter habitat-selection model for Alberta sage-grouse; 2) spatially depict habitat suitability in a Geographic Information System to identify areas with a high probability of selection and thus, conservation importance; and 3) assess the relative influence of human development, including oil and gas wells, in landscape models of winter habitat selection. Terrain and vegetation characteristics, sagebrush cover, anthropogenic landscape features, and energy development were important in top Akaike's Information Criterionselected models. During winter, sage-grouse selected dense sagebrush cover and homogenous less rugged areas, and avoided energy development and 2-track truck trails. Sage-grouse avoidance of energy development highlights the need for comprehensive management strategies that maintain suitable habitats across all seasons. ?? 2010 The Wildlife Society.

The Unusual Southern Hemisphere Stratosphere Winter of 2002

Science.gov (United States)

Newman, Paul A.; Nash, Eric R.

2003-01-01

The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The first large event occurred on 15 May, and the final warming occurred on 25 October. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen-Palm flux vectors. The wave events tended to occur irregularly over the course of the winter, and pre-conditioned the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major stratospheric warming in the southern hemisphere. This wave event split the Antarctic ozone hole. The combined effect of the wave events of the 2002 winter resulted in the smallest ozone hole observed since 1988.

Surface-exchange of NOx and NH3 above a winter wheat field in the Yangtze Delta, China

Institute of Scientific and Technical Information of China (English)

FANG Shuan-gxi; ZHANG Yi; MU Yu-jing

2006-01-01

A four-dynamic-chamber system was constructed to measure NOx and NH3 surface-exchange between a typical wheat field and the fluxes of NO2 and NH3 were negatively correlated with their ambient concentrations during the investigated period. The compensation point of NO2 between the wheat field and the atmosphere was 11.9 μg/m3. The emissions of NO-N and NH3-N from the urea applied to the wheat field were 2.3% and 0.2%, respectively, which indicated that the main pathway of N loss from the investigated winter wheat field was NO. Application of a mixture of urea and lignin increased the emissions of NO, but also greatly increased the yield of the winter wheat.

Return periods of losses associated with European windstorm series in a changing climate

International Nuclear Information System (INIS)

Karremann, Melanie K; Pinto, Joaquim G; Reyers, Mark; Klawa, Matthias

2014-01-01

Possible future changes of clustering and return periods (RPs) of European storm series with high potential losses are quantified. Historical storm series are identified using 40 winters of reanalysis. Time series of top events (1, 2 or 5 year return levels (RLs)) are used to assess RPs of storm series both empirically and theoretically. Additionally, 800 winters of general circulation model simulations for present (1960–2000) and future (2060–2100) climate conditions are investigated. Clustering is identified for most countries, and estimated RPs are similar for reanalysis and present day simulations. Future changes of RPs are estimated for fixed RLs and fixed loss index thresholds. For the former, shorter RPs are found for Western Europe, but changes are small and spatially heterogeneous. For the latter, which combines the effects of clustering and event ranking shifts, shorter RPs are found everywhere except for Mediterranean countries. These changes are generally not statistically significant between recent and future climate. However, the RPs for the fixed loss index approach are mostly beyond the range of pre-industrial natural climate variability. This is not true for fixed RLs. The quantification of losses associated with storm series permits a more adequate windstorm risk assessment in a changing climate. (letter)

Determining Inorganic and Organic Carbon.

Science.gov (United States)

Koistinen, Jaana; Sjöblom, Mervi; Spilling, Kristian

2017-11-21

Carbon is the element which makes up the major fraction of lipids and carbohydrates, which could be used for making biofuel. It is therefore important to provide enough carbon and also follow the flow into particulate organic carbon and potential loss to dissolved organic forms of carbon. Here we present methods for determining dissolved inorganic carbon, dissolved organic carbon, and particulate organic carbon.

Deer Wintering Areas

Data.gov (United States)

Vermont Center for Geographic Information — Deer winter habitat is critical to the long term survival of white-tailed deer (Odocoileus virginianus) in Vermont. Being near the northern extreme of the...

Spatially explicit modeling of conflict zones between wildlife and snow sports: prioritizing areas for winter refuges.

Science.gov (United States)

Braunisch, Veronika; Patthey, Patrick; Arlettaz, Raphaël

2011-04-01

Outdoor winter recreation exerts an increasing pressure upon mountain ecosystems, with unpredictable, free-ranging activities (e.g., ski mountaineering, snowboarding, and snowshoeing) representing a major source of stress for wildlife. Mitigating anthropogenic disturbance requires the spatially explicit prediction of the interference between the activities of humans and wildlife. We applied spatial modeling to localize conflict zones between wintering Black Grouse (Tetrao tetrix), a declining species of Alpine timberline ecosystems, and two free-ranging winter sports (off-piste skiing [including snow-boarding] and snowshoeing). Track data (snow-sports and birds' traces) obtained from aerial photographs taken over a 585-km transect running along the timberline, implemented within a maximum entropy model, were used to predict the occurrence of snow sports and Black Grouse as a function of landscape characteristics. By modeling Black Grouse presence in the theoretical absence of free-ranging activities and ski infrastructure, we first estimated the amount of habitat reduction caused by these two factors. The models were then extrapolated to the altitudinal range occupied by Black Grouse, while the spatial extent and intensity of potential conflict were assessed by calculating the probability of human-wildlife co-occurrence. The two snow-sports showed different distribution patterns. Skiers' occurrence was mainly determined by ski-lift presence and a smooth terrain, while snowshoers' occurrence was linked to hiking or skiing routes and moderate slopes. Wintering Black Grouse avoided ski lifts and areas frequented by free-ranging snow sports. According to the models, Black Grouse have faced a substantial reduction of suitable wintering habitat along the timberline transect: 12% due to ski infrastructure and another 16% when adding free-ranging activities. Extrapolating the models over the whole study area results in an overall habitat loss due to ski infrastructure of

Chloride Concentration in the Soil Polluted with Bishophit Used in Winter and its Effect on Herbaceous Plants

Directory of Open Access Journals (Sweden)

Asta Strėlkutė

2014-10-01

Full Text Available For road maintenance in winter, various chemical reagents, considering their physical and chemical properties, are chosen taking into account economic indicators. After a long winter season, large amounts of chemical reagents are used. During the winter season, dusting chlorides, first of all, fall on the roadway and a part of those reach roadsides where directly pollute the soil of the buffer zone and affect vegetation during the growing season. Chloride content in soil reduces the absorption of nutrients, which hinders the development of plants. It also has an effect on the metabolism of soil organisms, and therefore the loss of soil fertility. Due to high chloride content, land becomes unsuitable for plant growth. Studies used different concentrations (9 ml, 12 ml and 46 ml of bishophit. Chloride concentration in soil extract has been determined applying the volumetric method and employing silver nitrate titration. It has been determined that the amount of chloride in the soil contaminated with 9 ml makes 89.21 mg/kg, 12 ml – 94, 25 mg/kg and 164.32 mg/kg.

Winter climate limits subantarctic low forest growth and establishment.

Directory of Open Access Journals (Sweden)

Melanie A Harsch

Full Text Available Campbell Island, an isolated island 600 km south of New Zealand mainland (52 °S, 169 °E is oceanic (Conrad Index of Continentality  =  -5 with small differences between mean summer and winter temperatures. Previous work established the unexpected result that a mean annual climate warming of c. 0.6 °C since the 1940's has not led to upward movement of the forest limit. Here we explore the relative importance of summer and winter climatic conditions on growth and age-class structure of the treeline forming species, Dracophyllum longifolium and Dracophyllum scoparium over the second half of the 20th century. The relationship between climate and growth and establishment were evaluated using standard dendroecological methods and local climate data from a meteorological station on the island. Growth and establishment were correlated against climate variables and further evaluated within hierarchical regression models to take into account the effect of plot level variables. Winter climatic conditions exerted a greater effect on growth and establishment than summer climatic conditions. Establishment is maximized under warm (mean winter temperatures >7 °C, dry winters (total winter precipitation <400 mm. Growth, on the other hand, is adversely affected by wide winter temperature ranges and increased rainfall. The contrasting effect of winter warmth on growth and establishment suggests that winter temperature affects growth and establishment through differing mechanisms. We propose that milder winters enhance survival of seedlings and, therefore, recruitment, but increases metabolic stress on established plants, resulting in lower growth rates. Future winter warming may therefore have complex effects on plant growth and establishment globally.

Winter Climate Limits Subantarctic Low Forest Growth and Establishment

Science.gov (United States)

Harsch, Melanie A.; McGlone, Matt S.; Wilmshurst, Janet M.

2014-01-01

Campbell Island, an isolated island 600 km south of New Zealand mainland (52°S, 169°E) is oceanic (Conrad Index of Continentality  = −5) with small differences between mean summer and winter temperatures. Previous work established the unexpected result that a mean annual climate warming of c. 0.6°C since the 1940's has not led to upward movement of the forest limit. Here we explore the relative importance of summer and winter climatic conditions on growth and age-class structure of the treeline forming species, Dracophyllum longifolium and Dracophyllum scoparium over the second half of the 20th century. The relationship between climate and growth and establishment were evaluated using standard dendroecological methods and local climate data from a meteorological station on the island. Growth and establishment were correlated against climate variables and further evaluated within hierarchical regression models to take into account the effect of plot level variables. Winter climatic conditions exerted a greater effect on growth and establishment than summer climatic conditions. Establishment is maximized under warm (mean winter temperatures >7 °C), dry winters (total winter precipitation <400 mm). Growth, on the other hand, is adversely affected by wide winter temperature ranges and increased rainfall. The contrasting effect of winter warmth on growth and establishment suggests that winter temperature affects growth and establishment through differing mechanisms. We propose that milder winters enhance survival of seedlings and, therefore, recruitment, but increases metabolic stress on established plants, resulting in lower growth rates. Future winter warming may therefore have complex effects on plant growth and establishment globally. PMID:24691026

Effects of over-winter green cover on soil solution nitrate concentrations beneath tillage land.

Science.gov (United States)

Premrov, Alina; Coxon, Catherine E; Hackett, Richard; Kirwan, Laura; Richards, Karl G

2014-02-01

There is a growing need to reduce nitrogen losses from agricultural systems to increase food production while reducing negative environmental impacts. The efficacy of vegetation cover for reducing nitrate leaching in tillage systems during fallow periods has been widely investigated. Nitrate leaching reductions by natural regeneration (i.e. growth of weeds and crop volunteers) have been investigated to a lesser extent than reductions by planted cover crops. This study compares the efficacy of natural regeneration and a sown cover crop (mustard) relative to no vegetative cover under both a reduced tillage system and conventional plough-based system as potential mitigation measures for reducing over-winter soil solution nitrate concentrations. The study was conducted over three winter fallow seasons on well drained soil, highly susceptible to leaching, under temperate maritime climatic conditions. Mustard cover crop under both reduced tillage and conventional ploughing was observed to be an effective measure for significantly reducing nitrate concentrations. Natural regeneration under reduced tillage was found to significantly reduce the soil solution nitrate concentrations. This was not the case for the natural regeneration under conventional ploughing. The improved efficacy of natural regeneration under reduced tillage could be a consequence of potential stimulation of seedling germination by the autumn reduced tillage practices and improved over-winter plant growth. There was no significant effect of tillage practices on nitrate concentrations. This study shows that over winter covers of mustard and natural regeneration, under reduced tillage, are effective measures for reducing nitrate concentrations in free draining temperate soils. © 2013.

Light-Weight Low-Loss Dielectric Polymer Composites Containing Carbon Nanostructure

Science.gov (United States)

2014-10-17

Huang, J. Electrical Conductivity and Electromagnetic Interference Shielding Characteristics of Multiwalled Carbon Nanotube Filled Polyacrylate ...Highly Conductive Graphene Nanoribbons by Longitudinal Splitting of Carbon Nanotubes Using Potassium Vapor. ACS Nano 2011, 5, 968-974. 17. Lu, W.; Ruan...conductive GNRs, prepared using sodium/ potassium unzipping of multiwall carbon nanotubes, can boost the lithium storage performance of SnO2 NPs. The

Chapter 7: Migration and winter ecology

Science.gov (United States)

Deborah M. Finch; Jeffrey F. Kelly; Jean-Luc E. Cartron

2000-01-01

The willow flycatcher (Empidonax traillii) is a Neotropical migrant that breeds in North America, but winters in Central and northern South America. Little specific information is known about migration and wintering ecology of the southwestern willow flycatcher (E. t. extimus) (Yong and Finch 1997). Our report applies principally...

Correlations between land covers and honey bee colony losses in a country with industrialized and rural regions.

Science.gov (United States)

Clermont, Antoine; Eickermann, Michael; Kraus, François; Hoffmann, Lucien; Beyer, Marco

2015-11-01

High levels of honey bee colony losses were recently reported from Canada, China, Europe, Israel, Turkey and the United States, raising concerns of a global pollinator decline and questioning current land use practices, in particular intense agricultural cropping systems. Sixty-seven crops (data from the years 2010-2012) and 66 mid-term stable land cover classes (data from 2007) were analysed for statistical relationships with the honey bee colony losses experienced over the winters 2010/11-2012/13 in Luxembourg (Western Europe). The area covered by each land cover class, the shortest distance between each land cover class and the respective apiary, the number of plots covered by each land use class and the size of the biggest plot of each land cover class within radii of 2 km and 5 km around 166 apiaries (2010), 184 apiaries (2011) and 188 apiaries (2012) were tested for correlations with honey bee colony losses (% per apiary) experienced in the winter following the season when the crops were grown. Artificial water bodies, open urban areas, large industrial facilities including heavy industry, railways and associated installations, buildings and installations with socio-cultural purpose, camping-, sports-, playgrounds, golf courts, oilseed crops other than oilseed rape like sunflower or linseed, some spring cereals and former forest clearcuts or windthrows were the land cover classes most frequently associated with high honey bee colony losses. Grain maize, mixed forest and mixed coniferous forest were the land cover classes most frequently associated with low honey bee colony losses. The present data suggest that land covers related to transport, industry and leisure may have made a more substantial contribution to winter honey bee colony losses in developed countries than anticipated so far. Recommendations for the positioning of apiaries are discussed. Copyright © 2015. Published by Elsevier B.V.

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

Large-scale evaluation of pea (Pisum sativum L.) germplasm for cold tolerance in the open field during winter in Qingdao.

Science.gov (United States)

As a cool season crop, pea (Pisum sativum L.) can tolerate frost at the vegetative stage but has yield loss when freezing stress occurs at reproductive stage. Cold tolerance improvement of pea varieties is important for the stable yield and the expansion of winter pea planting area. Under the natura...

Phytoplankton community response to carbon dioxide enrichment in winter incubation experiments

Science.gov (United States)

Coastal waters are experiencing changes in carbonate chemistry, including pH, in response to increases in atmospheric CO2 concentration and the microbial degradation of surplus organic matter associated with nutrient enrichment. The effects of this change on plankton communities ...

Ecuador's mangrove forest carbon stocks: a spatiotemporal analysis of living carbon holdings and their depletion since the advent of commercial aquaculture.

Science.gov (United States)

Hamilton, Stuart E; Lovette, John

2015-01-01

In this paper we estimate the living carbon lost from Ecuador's mangrove forests since the advent of export-focused shrimp aquaculture. We use remote sensing techniques to delineate the extent of mangroves and aquaculture at approximately decadal periods since the arrival of aquaculture in each Ecuadorian estuary. We then spatiotemporally calculate the carbon values of the mangrove forests and estimate the amount of carbon lost due to direct displacement by aquaculture. Additionally, we calculate the new carbon stocks generated due to mangrove reforestation or afforestation. This research introduces time and LUCC (land use / land cover change) into the tropical forest carbon literature and examines forest carbon loss at a higher spatiotemporal resolution than in many earlier analyses. We find that 80 percent, or 7,014,517 t of the living carbon lost in Ecuadorian mangrove forests can be attributed to direct displacement of mangrove forests by shrimp aquaculture. We also find that IPCC (Intergovernmental Panel on Climate Change) compliant carbon grids within Ecuador's estuaries overestimate living carbon levels in estuaries where substantial LUCC has occurred. By approaching the mangrove forest carbon loss question from a LUCC perspective, these findings allow for tropical nations and other intervention agents to prioritize and target a limited set of land transitions that likely drive the majority of carbon losses. This singular cause of transition has implications for programs that attempt to offset or limit future forest carbon losses and place value on forest carbon or other forest good and services.

Effects of sea-ice and biogeochemical processes and storms on under-ice water fCO2 during the winter-spring transition in the high Arctic Ocean: Implications for sea-air CO2 fluxes

Science.gov (United States)

Fransson, Agneta; Chierici, Melissa; Skjelvan, Ingunn; Olsen, Are; Assmy, Philipp; Peterson, Algot K.; Spreen, Gunnar; Ward, Brian

2017-07-01

We performed measurements of carbon dioxide fugacity (fCO2) in the surface water under Arctic sea ice from January to June 2015 during the Norwegian young sea ICE (N-ICE2015) expedition. Over this period, the ship drifted with four different ice floes and covered the deep Nansen Basin, the slopes north of Svalbard, and the Yermak Plateau. This unique winter-to-spring data set includes the first winter-time under-ice water fCO2 observations in this region. The observed under-ice fCO2 ranged between 315 µatm in winter and 153 µatm in spring, hence was undersaturated relative to the atmospheric fCO2. Although the sea ice partly prevented direct CO2 exchange between ocean and atmosphere, frequently occurring leads and breakup of the ice sheet promoted sea-air CO2 fluxes. The CO2 sink varied between 0.3 and 86 mmol C m-2 d-1, depending strongly on the open-water fractions (OW) and storm events. The maximum sea-air CO2 fluxes occurred during storm events in February and June. In winter, the main drivers of the change in under-ice water fCO2 were dissolution of CaCO3 (ikaite) and vertical mixing. In June, in addition to these processes, primary production and sea-air CO2 fluxes were important. The cumulative loss due to CaCO3 dissolution of 0.7 mol C m-2 in the upper 10 m played a major role in sustaining the undersaturation of fCO2 during the entire study. The relative effects of the total fCO2 change due to CaCO3 dissolution was 38%, primary production 26%, vertical mixing 16%, sea-air CO2 fluxes 16%, and temperature and salinity insignificant.

Winter climate variability and classification in the Bulgarian Mountainous Regions

International Nuclear Information System (INIS)

Petkova, Nadezhda; Koleva, Ekaterina

2004-01-01

The problems of snowiness and thermal conditions of winters are of high interest of investigations because of the more frequent droughts, occurred in the region. In the present study an attempt to reveal tendencies existing during the last 70 years of 20 th century in the course winter precipitation and,temperature as well as in some of the snow cover parameters. On the base of mean winter air temperature winters in the Bulgarian mountains were analyzed and classified. The main results of the study show that winter precipitation has decrease tendencies more significant in the highest parts of the mountains. On the other hand winter air temperature increases. It shows a relatively well-established maximum at the end of the studied period. In the Bulgarian mountains normal winters are about 35-40% of all winters. (Author)

Interim Report 'Winter smog and traffic'.

NARCIS (Netherlands)

Bloemen, H.; Blom, T.; Bogaard, van den C.; Boluyt, N.; Bree, van L.; Brunekreef, B.; Hoek, G.; Zee, van der S.

1994-01-01

This report presents a halfway score of the research project "Winter smog and Traffic", one of the themes of the research programme "Air Pollution and Health". A state of the art is presented of the health effects associated with exposure to winter smog and of the toxicological effects caused by the

Expanding dryland ecosystem flux datasets enable novel quantification of water availability and carbon exchange in Southwestern North America

Science.gov (United States)

Biederman, J. A.; Scott, R. L.; Smith, W. K.; Litvak, M. E.; MacBean, N.

2017-12-01

Global-scale studies suggest that water-limited dryland ecosystems dominate the increasing trend in magnitude and interannual variability of the land CO2 sink. However, the terrestrial biosphere models and remote sensing models used in large-scale analyses are poorly constrained by flux measurements in drylands, which are under-represented in global datasets. In this talk, I will address this gap with eddy covariance data from 30 ecosystems across the Southwest of North America with observed ranges in annual precipitation of 100 - 1000 mm, annual temperatures of 2 - 25 °C, and records of 3 - 10 years each (160 site-years). This extensive dryland dataset enables new approaches including 1) separation of temporal and spatial patterns to infer fast and slow ecosystem responses to change, and 2) partitioning of precipitation into hydrologic losses, evaporation, and ecosystem-available water. I will then compare direct flux measurements with models and remote sensing used to scale fluxes regionally. Combining eddy covariance and streamflow measurements, I will show how evapotranspiration (ET), which is the efflux of soil moisture remaining after hydrologic losses, is a better metric than precipitation of water available to drive ecosystem CO2 exchange. Furthermore, I will present a novel method to partition ET into evaporation and transpiration using the tight coupling of transpiration and photosynthesis. In contrast with typical carbon sink function in wetter, more-studied regions, dryland sites express an annual net carbon uptake varying from -350 to +330 gC m-2. Due to less respiration losses relative to photosynthesis gains during winter, declines in winter precipitation across the Southwest since 1999 are reducing annual net CO2 uptake. Interannual variability of net uptake is larger than for wetter regions, and half the sites pivot between sinks in wet years to sources in dry years. Biospheric and remote sensing models capture only 20-30 % of interannual

Home advantage in the Winter Paralympic Games 1976-2014.

Science.gov (United States)

Wilson, Darryl; Ramchandani, Girish

2017-01-01

There is a limited amount of home advantage research concerned with winter sports. There is also a distinct lack of studies that investigate home advantage in the context of para sport events. This paper addresses this gap in the knowledge by examining home advantage in the Winter Paralympic Games. Using a standardised measure of success, we compared the performances of host nations at home with their own performances away from home between 1976 and 2014. Both country level and individual sport level analysis is conducted for this time period. Comparisons are also drawn with the Winter Olympic Games since 1992, the point from which both the Winter Olympic Games and the Winter Paralympic Games have been hosted by the same nations and in the same years. Clear evidence of a home advantage effect in the Winter Paralympic Games was found at country level. When examining individual sports, only alpine skiing and cross country skiing returned a significant home advantage effect. When comparing home advantage in the Winter Paralympic Games with the Winter Olympic Games for the last seven host nations (1992-2014), we found that home advantage was generally more pronounced (although not a statistically significant difference) in the case of the former. The causes of home advantage in the Winter Paralympic Games are unclear and should be investigated further.

Reduced irrigation increases the water use efficiency and productivity of winter wheat-summer maize rotation on the North China Plain.

Science.gov (United States)

Wang, Yunqi; Zhang, Yinghua; Zhang, Rui; Li, Jinpeng; Zhang, Meng; Zhou, Shunli; Wang, Zhimin

2018-03-15

The groundwater table has fallen sharply over the last 30years on the North China Plain, resulting in a shortage of water for winter wheat irrigation. Reducing irrigation may be an important strategy to maintain agricultural sustainability in the region; however, few studies have evaluated the transition from conventional irrigation management practices to reduced irrigation management practices in the winter wheat-summer maize rotation system. Here, we compare the yield, water consumption, and water use efficiency of winter wheat-summer maize rotation under conventional irrigation and reduced irrigation on the North China Plain from 2012 to 2015. Reducing irrigation decreased the yield but increased the water use efficiency and significantly advanced the harvest date of winter wheat. As a result, the summer maize sowing date advanced significantly, and the flowering date subsequently advanced 2-8days, thus extending the summer maize grain-filling stage. Therefore, the yield and water use efficiency of summer maize were higher under reduced irrigation than conventional irrigation, which compensated for the winter wheat yield loss under reduced irrigation. In addition, under reduced irrigation from 2012 to 2015, the yield and water use efficiency advantage of the winter wheat-summer maize rotation ranged from 0.0 to 9.7% and from 4.1 to 14.7%, respectively, and water consumption and irrigated water decreased by 20-61mm and 150mm, respectively, compared to conventional irrigation. Overall, the reduced irrigation management practice involving no irrigation after sowing winter wheat, and sowing summer maize on June 7 produced the most favorable grain yield with superb water use efficiency in the winter wheat-summer maize rotation. This study indicates that reducing irrigation could be an efficient means to cope with water resource shortages while maintaining crop production sustainability on the North China Plain. Copyright © 2017. Published by Elsevier B.V.

Real-time weed detection, decision making and patch spraying in maize, sugarbeet, winter wheat and winter barley

DEFF Research Database (Denmark)

Gerhards, R; Christensen, Svend

2003-01-01

with weed infestation levels higher than the economic weed threshold; a review of such work is provided. This paper presents a system for site-specific weed control in sugarbeet (Beta vulgaris L.), maize (Zea mays L.), winter wheat (Triticum aestivum L.) and winter barley (Hordeum vulgare L.), including...

Water losses during technical snow production

Science.gov (United States)

Grünewald, Thomas; Wolfsperger, Fabian

2017-04-01

These days, the production of technical snow can be seen as a prerequisite for winter tourism. Huge amounts of water are used for technical snow production by ski resorts, especially in the beginning of the winter season. The aim is to guarantee an appropriate amount of snow to reliably provide optimal ski runs until the date of season opening in early December. Technical snow is generated by pumping pressurized water through the nozzles of a snow machine and dispersing the resulting spray of small water droplets which freeze during their travel to the ground. Cooling and freezing of the droplets can only happen if energy is emitted to the air mass surrounding the droplets. This heat transfer is happening through convective cooling and though evaporation and sublimation of water droplets and ice particles. This means that also mass is lost from the droplets and added in form of vapor to the air. It is important to note that not all water that is pumped through the snow machine is converted to snow distributed on the ground. Significant amounts of water are lost due to wind drift, sublimation and evaporation while droplets are traveling through the air or to draining of water which is not fully frozen when arriving at the ground. Studies addressing this question are sparse and the quantity of the water losses is still unclear. In order to assess this question in more detail, we obtained several systematic field observations at a test site near Davos, Switzerland. About a dozen of snow making tests had been performed during the last winter seasons. We compare the amount of water measured at the intake of the snow machine with the amount of snow accumulating at the ground during a night of snow production. The snow mass was calculated from highly detailed repeated terrestrial laser scanning measurements in combination with manually gathered snow densities. In addition a meteorological station had been set up in the vicinity observing all relevant meteorological

Can we produce carbon and climate neutral forest bioenergy?

OpenAIRE

Repo, Anna; Tuovinen, Juha Pekka; Liski, Jari

2015-01-01

Harvesting branches, stumps and unmercantable tops, in addition to stem wood, decreases the carbon input to the soil and consequently reduces the forest carbon stock. We examine the changes in the forest carbon cycle that would compensate for this carbon loss over a rotation period and lead to carbon neutral forest residue bioenergy systems. In addition, we analyse the potential climate impact of these carbon neutral systems. In a boreal forest, the carbon loss was compensated for with a 10% ...

Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species

Science.gov (United States)

Firkus, Tyler; Rahel, Frank J.; Bergman, Harold L.; Cherrington, Brian D.

2018-02-01

We examined the spawning success of Fathead Minnows ( Pimephales promelas) and Johnny Darters ( Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures.

Winter barley mutants created in the Ukraine

International Nuclear Information System (INIS)

Zayats, O.M.

2001-01-01

Full text: Increasing fodder and protein production is one of the objectives of the development of agriculture in Ukraine. Higher productivity of fodder crops, due to new highly productive varieties, is the means to meet this aim. Winter barley is an important crop for fodder purposes. The climate of the Ukraine is favourable for growing this crop. The areas used for the growth of winter barley are however, small (500,000-550,000 ha) and there is a shortage of good quality varieties. The main aim of the work was therefore to create new varieties of highly productive winter barley, of good quality. The new varieties and mutation lines of winter barley were created under the influence of water solutions of N-nitroso-N-methylurea (NMH - 0,012, 0,005%), N-nitroso-N-ethylurea (NEH - 0,05; 0.025; 0,012%) ethyleneimine (EI - 0,02; 0,01; 0,005%) on winter barley seeds of the varieties of local and foreign selections. On the basis of many years of investigations (1984-94) the following mutations were described: hard-grained, winter-hardiness, earliness, middle-maturity, late-maturity, wide and large leaves, narrow leaves, multinodal, great number of leaves, great number of flowers, strong stem (lodging resistant), tallness, semi-dwarfness, dwarfness, and high productivity. Particularly valuable are mutants with high productivity of green bulk. Their potential yield is 70 t/ha. As a result of the work two varieties of winter barley 'Shyrokolysty' and 'Kormovy' were released into the State register of plant varieties of the Ukraine. The other valuable mutant genotypes are used in cross breeding programmes. (author)

Impacts of winter NPO on subsequent winter ENSO: sensitivity to the definition of NPO index

Science.gov (United States)

Chen, Shangfeng; Wu, Renguang

2018-01-01

This study investigates the linkage between boreal winter North Pacific Oscillation (NPO) and subsequent winter El Niño-Southern Oscillation (ENSO) based on seven different NPO indices. Results show that the influence of winter NPO on the subsequent winter El Niño is sensitive to how the NPO is defined. A significant NPO-El Niño connection is obtained when the NPO-related anomalous cyclone over the subtropical North Pacific extends to near-equatorial regions. The anomalous cyclone induces warm sea surface temperature (SST) anomalies through modulating surface heat fluxes. These warm SST anomalies are able to maintain into the following spring and summer through an air-sea coupled process and in turn induce significant westerly wind anomalies over the tropical western Pacific. In contrast, the NPO-El Niño relationship is unclear when the NPO-related anomalous cyclone over the subtropical North Pacific is confined to off-equatorial regions and cannot induce significant warm SST anomalies over the subtropical North Pacific. The present study suggests that definitions of NPO should be taken into account when using NPO to predict ENSO. In particular, we recommend defining the NPO index based on the empirical orthogonal function technique over appropriate region that does not extend too far north.

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.

Essential Outdoor Sun Safety Tips for Winter

Science.gov (United States)

... Weekend Warriors expand/collapse Vitamin D Essential Outdoor Sun Safety Tips for Winter Winter sports enthusiasts are ... skiing! Be Mindful of Time Spent in the Sun, Regardless of the Season If possible, ski early ...

Modeling Phosphorous Losses from Seasonal Manure Application Schemes

Science.gov (United States)

Menzies, E.; Walter, M. T.

2015-12-01

Excess nutrient loading, especially nitrogen and phosphorus, to surface waters is a common and significant problem throughout the United States. While pollution remediation efforts are continuously improving, the most effective treatment remains to limit the source. Appropriate timing of fertilizer application to reduce nutrient losses is currently a hotly debated topic in the Northeastern United States; winter spreading of manure is under special scrutiny. We plan to evaluate the loss of phosphorous to surface waters from agricultural systems under varying seasonal fertilization schemes in an effort to determine the impacts of fertilizers applied throughout the year. The Cayuga Lake basin, located in the Finger Lakes region of New York State, is a watershed dominated by agriculture where a wide array of land management strategies can be found. The evaluation will be conducted on the Fall Creek Watershed, a large sub basin in the Cayuga Lake Watershed. The Fall Creek Watershed covers approximately 33,000 ha in central New York State with approximately 50% of this land being used for agriculture. We plan to use the Soil and Water Assessment Tool (SWAT) to model a number of seasonal fertilization regimes such as summer only spreading and year round spreading (including winter applications), as well as others. We will use the model to quantify the phosphorous load to surface waters from these different fertilization schemes and determine the impacts of manure applied at different times throughout the year. More detailed knowledge about how seasonal fertilization schemes impact phosphorous losses will provide more information to stakeholders concerning the impacts of agriculture on surface water quality. Our results will help farmers and extensionists make more informed decisions about appropriate timing of manure application for reduced phosphorous losses and surface water degradation as well as aid law makers in improving policy surrounding manure application.

Late winter biogeochemical conditions under sea ice in the Canadian High Arctic

Directory of Open Access Journals (Sweden)

Helen S. Findlay

2015-12-01

Full Text Available With the Arctic summer sea-ice extent in decline, questions are arising as to how changes in sea-ice dynamics might affect biogeochemical cycling and phenomena such as carbon dioxide (CO2 uptake and ocean acidification. Recent field research in these areas has concentrated on biogeochemical and CO2 measurements during spring, summer or autumn, but there are few data for the winter or winter–spring transition, particularly in the High Arctic. Here, we present carbon and nutrient data within and under sea ice measured during the Catlin Arctic Survey, over 40 days in March and April 2010, off Ellef Ringnes Island (78° 43.11′ N, 104° 47.44′ W in the Canadian High Arctic. Results show relatively low surface water (1–10 m nitrate (<1.3 µM and total inorganic carbon concentrations (mean±SD=2015±5.83 µmol kg−1, total alkalinity (mean±SD=2134±11.09 µmol kg−1 and under-ice pCO2sw (mean±SD=286±17 µatm. These surprisingly low wintertime carbon and nutrient conditions suggest that the outer Canadian Arctic Archipelago region is nitrate-limited on account of sluggish mixing among the multi-year ice regions of the High Arctic, which could temper the potential of widespread under-ice and open-water phytoplankton blooms later in the season.

Patterns of Carbon Storage and Greenhouse Gas Losses in Urban Residential Lawns

Science.gov (United States)

Contosta, A.; Varner, R.; Xiao, J.

2017-12-01

Population density and housing age are two factors believed to impact carbon (C) storage and greenhouse gas emissions in one of the most extensively managed landscapes in the U.S.: the urban lawn. Previous research focusing on either above- or below-ground C dynamics has also not explicitly considered how they interact to affect the net carbon balance in urban residential areas. We addressed this knowledge gap by quantifying both soil and vegetative C stocks and greenhouse gas fluxes across an urban gradient in Manchester, NH, USA that included 34 lawns comprising three population density categories, five housing age classes, and the interaction between them. Using a combination of both weekly, manual measurements and continuous, automated estimates, we also sampled emissions of CH4, CO2, and N2O within a subset of these lawns that represented a range of citywide population density and housing age characteristics and management practices. We found that neither above- nor below-ground C storage varied with population density, but both differed among housing age classes. Soil C storage increased with housing age and was highest in the oldest lawns sampled. By contrast, C stocks in aboveground, woody biomass was highest at intermediate ages and lowest in older and new parcels. Unlike C stocks, soil greenhouse gas emissions did not change among population density categories, housing age classes, or with irrigation and fertilization management, but instead followed temporal trends in soil moisture and temperature. Overall, our results suggest that drivers of C storage and greenhouse gas losses in urban residential areas may not be uniform and their accurate representation in Earth system models may require a variety of approaches.

Dissolved inorganic carbon, pH and other variables measured from laboratory experiment studies from an experimental carbonate exposure system from 2013-05-15 to 2013-07-12 (NODC Accession 0123316)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains the carbon chemistry measurements of a laboratory experiment study to understand the effects of ocean acidification on winter...

Dissolved inorganic carbon, pH and other variables measured from laboratory experiment studies from an experimental carbonate exposure system from 2013-12-09 to 2014-01-31 (NODC Accession 0123317)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains the carbon chemistry measurements of a laboratory experiment study to understand the effects of ocean acidification on winter...

Dissolved inorganic carbon, pH and other variables measured from laboratory experiment studies from an experimental carbonate exposure system from 2012-02-29 to 2012-05-11 (NODC Accession 0123315)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains the carbon chemistry measurements of a laboratory experiment study to understand the effects of ocean acidification on winter...

Spatial and temporal variation in winter condition of juvenile Pacific herring (Clupea pallasii) in Prince William Sound, Alaska: Oceanographic exchange with the Gulf of Alaska

Science.gov (United States)

Gorman, Kristen B.; Kline, Thomas C.; Roberts, Megan E.; Sewall, Fletcher F.; Heintz, Ron A.; Pegau, W. Scott

2018-01-01

Spatial variability in early and late winter measures of whole body energy density of juvenile (age-0) Pacific herring (Clupea pallasii) of Prince William Sound (PWS), Alaska was examined over nine years of study. Pacific herring in this region remain considered as an injured resource over the 25 years following the Exxon Valdez oil spill, however factors responsible for the lack of recovery by herring in PWS are a source of ongoing debate. Given the species' key ecological role in energy transfer to higher predators, and its economic role in a historical commercial fishery within the region, significant research effort has focused on understanding environmental factors that shape nutritional processes and the quality of these young forage fish. During November (early winter), factors such as juvenile herring body size, hydrological region of PWS, year, and the interaction between carbon (δ13C‧) or nitrogen (δ15N) stable isotope signature and hydrological region were all important predictors of juvenile herring energy density. In particular, analyses indicated that in the northern and western regions of PWS, juvenile herring with more depleted δ13C‧ values (which reflect a Gulf of Alaska carbon source) were more energy dense. Results suggest that intrusion of water derived from the Gulf of Alaska enhances the condition of age-0 herring possibly through alterations in zooplankton community structure and abundance, particularly in the northern and western regions of PWS in the fall, which is consistent with regional circulation. During March (late winter), factors such as juvenile herring body size, year, and the interaction between δ13C‧ or δ15N isotope signature and year were all important predictors of juvenile herring energy density. Results differed for early and late winter regarding the interaction between stable isotope signatures and region or year, suggesting important seasonal aspects of circulation contribute to variation in PWS juvenile

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.

Warmed Winter Water Temperatures Alter Reproduction in Two Fish Species.

Science.gov (United States)

Firkus, Tyler; Rahel, Frank J; Bergman, Harold L; Cherrington, Brian D

2018-02-01

We examined the spawning success of Fathead Minnows (Pimephales promelas) and Johnny Darters (Etheostoma nigrum) exposed to elevated winter water temperatures typical of streams characterized by anthropogenic thermal inputs. When Fathead Minnows were exposed to temperature treatments of 12, 16, or 20 °C during the winter, spawning occurred at 16 and 20 °C but not 12 °C. Eggs were deposited over 9 weeks before winter spawning ceased. Fathead Minnows from the three winter temperature treatments were then exposed to a simulated spring transition. Spawning occurred at all three temperature treatments during the spring, but fish from the 16° and 20 °C treatment had delayed egg production indicating a latent effect of warm winter temperatures on spring spawning. mRNA analysis of the egg yolk protein vitellogenin showed elevated expression in female Fathead Minnows at 16 and 20 °C during winter spawning that decreased after winter spawning ceased, whereas Fathead Minnows at 12 °C maintained comparatively low expression during winter. Johnny Darters were exposed to 4 °C to represent winter temperatures in the absence of thermal inputs, and 12, 16, and 20 °C to represent varying degrees of winter thermal pollution. Johnny Darters spawned during winter at 12, 16, and 20 °C but not at 4 °C. Johnny Darters at 4 °C subsequently spawned following a simulated spring period while those at 12, 16, and 20 °C did not. Our results indicate elevated winter water temperatures common in effluent-dominated streams can promote out-of-season spawning and that vitellogenin expression is a useful indicator of spawning readiness for fish exposed to elevated winter temperatures.

Analysis of carbon dioxide, water vapour and energy fluxes over an ...

Indian Academy of Sciences (India)

over an Indian teak mixed deciduous forest for winter and summer ... Anderson and Verma 1986) and in natural ecosys- tems (Wesely ... ject of the 'National Carbon Project – NCP' – ..... productivity of planet earth: Biological determinants and.

Winter Wonderlands

Science.gov (United States)

Coy, Mary

2011-01-01

Listening to people complain about the hardships of winter and the dreariness of the nearly constant gray sky prompted the author to help her sixth graders recognize and appreciate the beauty that surrounds them for nearly five months of the year in western New York. The author opines that if students could see things more artistically, the winter…

Effects of winter temperature and summer drought on net ecosystem exchange of CO2 in a temperate peatland

Science.gov (United States)

Helfter, Carole; Campbell, Claire; Dinsmore, Kerry; Drewer, Julia; Coyle, Mhairi; Anderson, Margaret; Skiba, Ute; Nemitz, Eiko; Billett, Michael; Sutton, Mark

2014-05-01

Northern peatlands are one of the most important global sinks of atmospheric carbon dioxide (CO2); their ability to sequester C is a natural feedback mechanism controlled by climatic variables such as precipitation, temperature, length of growing season and period of snow cover. In the UK it has been predicted that peatlands could become a net source of carbon in response to climate change with climate models predicting a rise in global temperature of ca. 3oC between 1961-1990 and 2100. Land-atmosphere exchange of CO2in peatlands exhibits marked seasonal and inter-annual variations, which have significant short- and long-term effects on carbon sink strength. Net ecosystem exchange (NEE) of CO2 has been measured continuously by eddy-covariance (EC) at Auchencorth Moss (55° 47'32 N, 3° 14'35 W, 267 m a.s.l.), a temperate peatland in central Scotland, since 2002. Auchencorth Moss is a low-lying, ombrotrophic peatland situated ca. 20 km south-west of Edinburgh. Peat depth ranges from 5 m and the site has a mean annual precipitation of 1155 mm. The vegetation present within the flux measurement footprint comprises mixed grass species, heather and substantial areas of moss species (Sphagnum spp. and Polytrichum spp.). The EC system consists of a LiCOR 7000 closed-path infrared gas analyser for the simultaneous measurement of CO2 and water vapour and of a Gill Windmaster Pro ultrasonic anemometer. Over the 10 year period, the site was a consistent yet variable sink of CO2 ranging from -34.1 to -135.9 g CO2-C m-2 yr-1 (mean of -69.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing seasons and mean winter air temperature explained 93% of the variability in summertime sink strength, indicating a phenological memory-effect. Plant development and productivity were stunted by colder winters causing a net reduction in the annual carbon sink strength of this peatland where autotrophic processes are thought to be

Introducing carbon taxes in South Africa

International Nuclear Information System (INIS)

Alton, Theresa; Arndt, Channing; Davies, Rob; Hartley, Faaiqa; Makrelov, Konstantin; Thurlow, James; Ubogu, Dumebi

2014-01-01

Highlights: • South Africa is considering introducing a carbon tax to reduce greenhouse gas emissions. • A phased-in tax of US$30 per ton can achieve national emissions reductions targets set for 2025. • Ignoring all potential benefits, the tax reduces national welfare by about 1.2 percent in 2025. • Border carbon adjustments reduce welfare losses while maintaining emissions reductions. • The mode for recycling carbon tax revenues strongly influences distributional outcomes. - Abstract: South Africa is considering introducing a carbon tax to reduce greenhouse gas emissions. Following a discussion of the motivations for considering a carbon tax, we evaluate potential impacts using a dynamic economywide model linked to an energy sector model including a detailed evaluation of border carbon adjustments. Results indicate that a phased-in carbon tax of US$30 per ton of CO 2 can achieve national emissions reductions targets set for 2025. Relative to a baseline with free disposal of CO 2 , constant world prices and no change in trading partner behavior, the preferred tax scenario reduces national welfare and employment by about 1.2 and 0.6 percent, respectively. However, if trading partners unilaterally impose a carbon consumption tax on South African exports, then welfare/employment losses exceed those from a domestic carbon tax. South Africa can lessen welfare/employment losses by introducing its own border carbon adjustments. The mode for recycling carbon tax revenues strongly influences distributional outcomes, with tradeoffs between growth and equity

Classification guide: Sochi 2014 Paralympic Winter Games

OpenAIRE

2014-01-01

The Sochi 2014 Paralympic Winter Games classification guide is designed to provide National Paralympic Committees (NPCs) and International Federations (IFs) with information about the classification policies and procedures that will apply to the Sochi 2014 Paralympic Winter Games.

Exploratory Disposal and Reuse Feasibility Analysis of Winter Maintenance Wash Water.

Science.gov (United States)

Ullinger, Heather L; Kennedy, Marla J; Schneider, William H; Miller, Christopher M

2016-01-01

The Ohio Department of Transportation has more than 60 facilities without sewer access generating approximately 19 million gallons of winter maintenance wash water. Off-site disposal is costly, creating the need for sustainable management strategies. The objective of this study was to conduct an exploratory feasibility analysis to assess wash water disposal and potential reuse as brine. Based on a comprehensive literature review and relevant environmental chemistry, a sampling protocol consisting of 31 water quality constituents was utilized for monthly sampling at three geographically distinct Ohio Department of Transportation garages during the winter of 2012. Results were compared to local disposal and reuse guidance limits. Three constituents, including a maximum copper concentration of 858 ppb, exceeded disposal limits, and many constituents also failed to meet reuse limits. Some concentrations were orders of magnitude higher than reuse limits and suggest pre-treatment would be necessary if wash water were reused as brine. These water quality results, in conjunction with copper chemical equilibrium modeling, show pH and dissolved carbon both significantly impact the total dissolved copper concentration and should be measured to assess reuse potential. The sampling protocol and specific obstacles highlighted in this paper aid in the future development of sustainable wash water management strategies.

Exploratory Disposal and Reuse Feasibility Analysis of Winter Maintenance Wash Water.

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Heather L Ullinger

Full Text Available The Ohio Department of Transportation has more than 60 facilities without sewer access generating approximately 19 million gallons of winter maintenance wash water. Off-site disposal is costly, creating the need for sustainable management strategies. The objective of this study was to conduct an exploratory feasibility analysis to assess wash water disposal and potential reuse as brine. Based on a comprehensive literature review and relevant environmental chemistry, a sampling protocol consisting of 31 water quality constituents was utilized for monthly sampling at three geographically distinct Ohio Department of Transportation garages during the winter of 2012. Results were compared to local disposal and reuse guidance limits. Three constituents, including a maximum copper concentration of 858 ppb, exceeded disposal limits, and many constituents also failed to meet reuse limits. Some concentrations were orders of magnitude higher than reuse limits and suggest pre-treatment would be necessary if wash water were reused as brine. These water quality results, in conjunction with copper chemical equilibrium modeling, show pH and dissolved carbon both significantly impact the total dissolved copper concentration and should be measured to assess reuse potential. The sampling protocol and specific obstacles highlighted in this paper aid in the future development of sustainable wash water management strategies.

Antarctic ozone loss in 1989-2010: evidence for ozone recovery?

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Kuttippurath, J.; Lefèvre, F.; Pommereau, J.-P.; Roscoe, H. K.; Goutail, F.; Pazmiño, A.; Shanklin, J. D.

2012-04-01

We present a detailed estimation of chemical ozone loss in the Antarctic polar vortex from 1989 to 2010. The analyses include ozone loss estimates for 12 Antarctic ground-based (GB) stations. All GB observations show minimum ozone in the late September-early October period. Among the stations, the lowest minimum ozone values are observed at South Pole and the highest at Dumont d'Urville. The ozone loss starts by mid-June at the vortex edge and then progresses towards the vortex core with time. The loss intensifies in August-September, peaks by the end of September-early October, and recovers thereafter. The average ozone loss in the Antarctic is revealed to be about 33-50% in 1989-1992 in agreement with the increase in halogens during this period, and then stayed at around 48% due to saturation of the loss. The ozone loss in the warmer winters (e.g. 2002, and 2004) is lower (37-46%) and in the colder winters (e.g. 2003, and 2006) is higher (52-55%). Because of small inter-annual variability, the correlation between ozone loss and the volume of polar stratospheric clouds yields ~0.51. The GB ozone and ozone loss values are in good agreement with those found from the space-based observations of the Total Ozone Mapping Spectrometer/Ozone Monitoring Instrument (TOMS/OMI), the Global Ozone Monitoring Experiment (GOME), the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and the Aura Microwave Limb Sounder (MLS), where the differences are within ±5% and are mostly within the error bars of the measurements. The piece-wise linear trends computed from the September-November vortex average GB and TOMS/OMI ozone show about -4 to -5.6 DU (Dobson Unit) yr-1 in 1989-1996 and about +1 DU yr-1 in 1997-2010. The trend during the former period is significant at 95% confidence intervals, but the trend in 1997-2010 is significant only at 85% confidence intervals. Our analyses suggest a period of about 9-10 yr to get the first detectable ozone

The importance of terrestrial carbon in supporting molluscs in the wetlands of Poyang Lake

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Zhang, Huan; Yu, Xiubo; Wang, Yuyu; Xu, Jun

2017-07-01

Allochthonous organic matter plays an important role in nutrient cycling and energy mobilization in freshwater ecosystems. However, the subsidies of this carbon source in floodplain ecosystems have not yet well understood. We used a Bayesian mixing model and stable isotopes (δ13C and δ15N) of primary food resources and dominant molluscs species, to estimate the relative importance of allochthonous carbon sources for consumers in a representative sub-lake of Poyang Lake during a prolonged dry season. Our study inferred that terrestrial-derived carbon from Carex spp. could be the primary contributor to snails and mussels in Dahuchi Lake. The mean percentage of allochthonous food resources accounted for 35%-50% of the C incorporated by these consumers. Seston was another important energy sources for benthic consumers. However, during the winter and low water-level period, benthic algae and submerged vegetation contributed less carbon to benthic consumers. Our data highlighted the importance of terrestrial organic carbon to benthic consumers in the wetlands of Poyang Lake during the prolonged dry period. Further, our results provided a perspective that linkages between terrestrial and aquatic ecosystems might be facilitated by wintering geese via their droppings.

Micrometeorological Measurements Reveal Large Nitrous Oxide Losses during Spring Thaw in Alberta

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Thomas K. Flesch

2018-03-01

Full Text Available Agricultural soils in Canada have been observed to emit a large pulse of nitrous oxide (N2O gas during the spring thaw, representing a large percentage of the annual emissions. We report on three years of spring thaw N2O flux measurements taken at three Alberta agricultural sites: a crop production site (Crop, cattle winter-feeding site (WF, and a cattle winter-grazing site (WG. Soil fluxes were calculated with a micrometeorological technique based on the vertical gradient in N2O concentration above each site measured with an open-path (line-averaging FTIR gas detector. The Crop and WG sites showed a clear N2O emission pulse lasting 10 to 25 days after thawing began. During this pulse there was a strong diurnal cycle in emissions that paralleled the cycle in near-surface soil temperature. The emission pulse was less pronounced at the WF site. The average spring thaw losses (over 25 to 31 days were 5.3 (Crop, 7.0 (WF, and 8.0 (WG kg N2O-N ha−1, representing 1 to 3.5% of the annual nitrogen input to the sites. These large losses are higher than found in most previous western Canadian studies, and generally higher than the annual losses estimated from the Intergovernmental Panel on Climate Change and Canadian National Inventory Report calculations. The high N2O losses may be explained by high soil nitrate levels which promoted rapid denitrification during thawing. The application of a high resolution (temporal micrometeorological technique was critical to revealing these losses.

Oxidative Attack of Carbon/Carbon Substrates through Coating Pinholes

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Jacobson, Nathan S.; Leonhardt, Todd; Curry, Donald; Rapp, Robert A.

1998-01-01

A critical issue with oxidation protected carbon/carbon composites used for spacecraft thermal protection is the formation of coating pinholes. In laboratory experiments, artificial pinholes were drilled through SiC-coatings on a carbon/carbon material and the material was oxidized at 600, 1000, and 1400 C at reduced pressures of air. The attack of the carbon/carbon was quantified by both weight loss and a novel cross-sectioning technique. A two-zone, one dimensional diffusion control model was adapted to analyze this problem. Agreement of the model with experiment was reasonable at 1000 and 1400 C; however results at lower temperatures show clear deviations from the theory suggesting that surface reaction control plays a role.

Carbon stock and carbon turnover in boreal and temperate forests - Integration of remote sensing data and global vegetation models

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Thurner, Martin; Beer, Christian; Carvalhais, Nuno; Forkel, Matthias; Tito Rademacher, Tim; Santoro, Maurizio; Tum, Markus; Schmullius, Christiane

2016-04-01

Long-term vegetation dynamics are one of the key uncertainties of the carbon cycle. There are large differences in simulated vegetation carbon stocks and fluxes including productivity, respiration and carbon turnover between global vegetation models. Especially the implementation of climate-related mortality processes, for instance drought, fire, frost or insect effects, is often lacking or insufficient in current models and their importance at global scale is highly uncertain. These shortcomings have been due to the lack of spatially extensive information on vegetation carbon stocks, which cannot be provided by inventory data alone. Instead, we recently have been able to estimate northern boreal and temperate forest carbon stocks based on radar remote sensing data. Our spatially explicit product (0.01° resolution) shows strong agreement to inventory-based estimates at a regional scale and allows for a spatial evaluation of carbon stocks and dynamics simulated by global vegetation models. By combining this state-of-the-art biomass product and NPP datasets originating from remote sensing, we are able to study the relation between carbon turnover rate and a set of climate indices in northern boreal and temperate forests along spatial gradients. We observe an increasing turnover rate with colder winter temperatures and longer winters in boreal forests, suggesting frost damage and the trade-off between frost adaptation and growth being important mortality processes in this ecosystem. In contrast, turnover rate increases with climatic conditions favouring drought and insect outbreaks in temperate forests. Investigated global vegetation models from the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), including HYBRID4, JeDi, JULES, LPJml, ORCHIDEE, SDGVM, and VISIT, are able to reproduce observation-based spatial climate - turnover rate relationships only to a limited extent. While most of the models compare relatively well in terms of NPP, simulated

Carbon transfer from photosynthesis to below ground fine root/hyphae respiration in Quercus serrata using stable carbon isotope pulse labeling

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Dannoura, M.; Kominami, Y.; Takanashi, S.; Takahashi, K.

2013-12-01

Studying carbon allocation in trees is a key to better understand belowground carbon cycle and its response to climate change. Tracing 13C in tree and soil compartments after pulse labeling is one of powerful tool to study the fate of carbon in forest ecosystems. This experiment was conducted in Yamashiro experimental forest, Kyoto, Japan. Annual mean temperature and precipitation from 1994 to 2009 are 15.5 ° C and 1,388 mm respectively. The branch pulse labeling were done 7 times in 2011 using same branch of Quercus serrata (H:11.7 m, DBH; 33.7 cm) to see seasonal variations of carbon velocity. Whole crown labeling of Quercus serrata (H:9 m, DBH; 13.7 cm) was done in 2012 to study carbon allocation and to especially focus on belowground carbon flux until to the hyphae respiration. Pure 13CO2 (99.9%) was injected to the labeling chamber which was set to branch or crown. Then, after one hour of branch labeling and 3.5 hour for crown labeling, the chamber was opened. Trunk respiration chambers, fine root chambers and hyphae chambers were set to the target tree to trace labeled carbon in the CO2 efflux. 41 μm mesh was used to exclude ingrowth of roots into hyphae chambers. The results show that the velocity of carbon through the tree varied seasonally, with higher velocity in summer than autumn, averaging 0.47 m h-1. Half-lives of labeled carbon in autotrophic respiration were similar above and below ground during the growing season, but they were twice longer in trunk than in root in autumn. From the whole crown labeling done end of growing season, the 13CO2 signal was observed 25 hours after labeling in trunk chamber and 34-37.7 hours after labeling in fine root and hyphae respiration almost simultaneously. Half-lives of 13 was longer in trunk than below ground. Trunk respiration was still using labelled carbon during winter suggesting that winter trunk respiration is partly fueled by carbon stored in the trunk at the end of the growing season.

Winter chilling speeds spring development of temperate butterflies.

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Stålhandske, Sandra; Gotthard, Karl; Leimar, Olof

2017-07-01

Understanding and predicting phenology has become more important with ongoing climate change and has brought about great research efforts in the recent decades. The majority of studies examining spring phenology of insects have focussed on the effects of spring temperatures alone. Here we use citizen-collected observation data to show that winter cold duration, in addition to spring temperature, can affect the spring emergence of butterflies. Using spatial mixed models, we disentangle the effects of climate variables and reveal impacts of both spring and winter conditions for five butterfly species that overwinter as pupae across the UK, with data from 1976 to 2013 and one butterfly species in Sweden, with data from 2001 to 2013. Warmer springs lead to earlier emergence in all species and milder winters lead to statistically significant delays in three of the five investigated species. We also find that the delaying effect of winter warmth has become more pronounced in the last decade, during which time winter durations have become shorter. For one of the studied species, Anthocharis cardamines (orange tip butterfly), we also make use of parameters determined from previous experiments on pupal development to model the spring phenology. Using daily temperatures in the UK and Sweden, we show that recent variation in spring temperature corresponds to 10-15 day changes in emergence time over UK and Sweden, whereas variation in winter duration corresponds to 20 days variation in the south of the UK versus only 3 days in the south of Sweden. In summary, we show that short winters delay phenology. The effect is most prominent in areas with particularly mild winters, emphasising the importance of winter for the response of ectothermic animals to climate change. With climate change, these effects may become even stronger and apply also at higher latitudes. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Saptial and Temporal in Stable Carbon and Oxygen Isotope Ratios of Juvenile Winter Flounder Otoliths From Selected Nursery Areas

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Winter flounder (Pseudopleuronectes americanus) populations have supported large commercial and recreational fisheries along the coast of New England. In recent years, however, the population of this important species has declined precipitously in some areas, especially Narragan...

Directed graph based carbon flow tracing for demand side carbon obligation allocation

DEFF Research Database (Denmark)

Sun, Tao; Feng, Donghan; Ding, Teng

2016-01-01

In order to achieve carbon emission abatement, some researchers and policy makers have cast their focus on demand side carbon abatement potentials. This paper addresses the problem of carbon flow calculation in power systems and carbon obligation allocation at demand side. A directed graph based...... method for tracing carbon flow is proposed. In a lossy network, matrices such as carbon losses, net carbon intensity (NCI) and footprint carbon intensity (FCI) are obtained with the proposed method and used to allocate carbon obligation at demand side. Case studies based on realistic distribution...... and transmission systems are provided to demonstrate the effectiveness of the proposed method....

Large carbon dioxide fluxes from headwater boreal and sub-boreal streams.

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Venkiteswaran, Jason J; Schiff, Sherry L; Wallin, Marcus B

2014-01-01

Half of the world's forest is in boreal and sub-boreal ecozones, containing large carbon stores and fluxes. Carbon lost from headwater streams in these forests is underestimated. We apply a simple stable carbon isotope idea for quantifying the CO2 loss from these small streams; it is based only on in-stream samples and integrates over a significant distance upstream. We demonstrate that conventional methods of determining CO2 loss from streams necessarily underestimate the CO2 loss with results from two catchments. Dissolved carbon export from headwater catchments is similar to CO2 loss from stream surfaces. Most of the CO2 originating in high CO2 groundwaters has been lost before typical in-stream sampling occurs. In the Harp Lake catchment in Canada, headwater streams account for 10% of catchment net CO2 uptake. In the Krycklan catchment in Sweden, this more than doubles the CO2 loss from the catchment. Thus, even when corrected for aquatic CO2 loss measured by conventional methods, boreal and sub-boreal forest carbon budgets currently overestimate carbon sequestration on the landscape.

Hydrodynamic Controls on Carbon Dioxide Efflux from Inland Waters

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Long, H. E.; Waldron, S.; Hoey, T.; Newton, J.; Quemin, S.

2013-12-01

Intensive research has been undertaken on carbon dioxide efflux from lakes, estuaries and oceans, but much less attention has been given to rivers and streams, especially lower order streams. River systems are often over-saturated with carbon dioxide and so tend to act as sources of carbon dioxide to the atmosphere. It has been thought that rivers act as pipes carrying this terrestrial carbon to the oceans. However, recent studies have shown that a significant amount of the carbon is reprocessed within the system in a series of transformations and losses. Fluvial evasion of carbon dioxide is now recognised to be a significant component of carbon cycles, however the factors controlling carbon dioxide efflux and its magnitude remain poorly understood and quantified. This research aims to quantify, and better understand the controls on, freshwater carbon dioxide evasion. Data are presented here from field measurements that commenced in Sept 2013 in two contrasting Scottish rivers: the River Kelvin which has a large (335 km.sq) part-urban catchment with predominantly non-peat soils and Drumtee Water, a small (9.6 km.sq) rural catchment of peat soils and agricultural land. Using a floating chamber with the headspace connected to an infrared gas analyser to measure changes in carbon dioxide concentration, efflux rates from 0.22 - 47.4 μmol CO2/m.sq/sec were measured, these close to the middle of the range of previously reported values. At one site on the River Kelvin in May 2013 an influx of -0.61 - -3.53 μmol CO2/m.sq/sec was recorded. Whereas previous research finds carbon dioxide efflux to increase with decreasing river size and a more organic-rich soil catchment, here the controls on carbon dioxide evasion are similar across the contrasting catchments. Carbon dioxide evasion shows seasonality, with maximum fluxes in the summer months being up to twice as high as the winter maxima. Linear regression demonstrates that evasion increases with increased flow velocity

The ability of cover crops to reduce nitrogen and phosphorus losses from arable land in southern Scandinavia and Finland

DEFF Research Database (Denmark)

Aronsson, H.; Hansen, Elly Møller; Thomsen, Ingrid Kaag

2016-01-01

]). The data indicate that CCs do not substantially reduce total P losses by runoff and leaching. The effects of CCs on total P leaching varied between a relative increase of 86% and a decrease of 43%. Climate conditions involving freezing-thawing during winter increased the risk of losses of dissolved P from...

Measurements of flux and isotopic composition of soil carbon dioxide

International Nuclear Information System (INIS)

Gorczyca, Z.; Rozanski, K.; Kuc, T.

2002-01-01

The flux and isotope composition of soil CO 2 has been regularly measured at three sites located in the southern Poland, during the time period: January 1998 - October 2000. They represent typical ecosystems appearing in central Europe: (i) mixed forest; (ii) cultivated agricultural field; (iii) grassland. To monitor the flux and isotopic composition of soil CO 2 , a method based on the inverted cup principle was adopted. The flux of soil CO 2 reveals distinct seasonal fluctuations, with maximum values up to ca. 25 mmol/m 2 /h during sommer months and around ten times lower values during winter time. Also significant differences among the monitored sites were detected, the flux density of this gas being highest for the mixed forest site and ca. two times lower for the cultivated grassland. Carbon-13 content of the soil CO 2 reveals little seasonal variability, with δ 13 C values essentially reflecting the isotopic composition of the soil organic matter and the vegetation type. The carbon-14 content of soil CO 2 flux also reveals slight seasonality, with lower δ 14 C values recorded during winter time. Significantly lower δ 14 C values recorded during winter time. Significantly lower δ 14 C values were recorded at depth. (author)

What Have We Learned About Arctic Carbon Since The First State of the Carbon Cycle Report?

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Schuur, E.

2015-12-01

Large pools of organic carbon were reported in The First State of the Carbon Cycle Report, but measurements from high latitude ecosystems, in particular for deeper soils >1m depth, remained scarce. A newly enlarged soil carbon database with an order of magnitude more numerous deep sampling sites has verified the widespread pattern of large quantities of carbon accumulated deep in permafrost (perennially frozen) soils. The known pool of permafrost carbon across the northern circumpolar permafrost zone is now estimated to be 1330-1580 Pg C, with the potential for an additional ~400 Pg C in deep permafrost sediments. In addition, an uncertainty estimate of plus/minus 15% has now been calculated for the soil carbon pool in the surface 0-3m. Laboratory incubations of these permafrost soils reveal that a significant fraction can be mineralized by microbes upon thaw and converted to carbon dioxide and methane on time scales of years to decades, with decade-long average losses from aerobic incubations ranging from 6-34% of initial carbon. Carbon emissions from the same soils incubated in an anaerobic environment are, on average, 78-85% lower than aerobic soils. But, the more potent greenhouse gas methane released under anaerobic conditions in part increases the climate impact of these emissions. While mean quantities of methane are only 3% to 7% that of carbon dioxide emitted from anaerobic incubations (by weight of C), these mean methane values represent 25% to 45% of the overall potential impact on climate when accounting for the higher global warming potential of methane. Taken together though, in spite of the more potent greenhouse gas methane, a unit of newly thawed permafrost carbon could have a greater impact on climate over a century if it thaws and decomposes within a drier, aerobic soil as compared to an equivalent amount of carbon within a waterlogged soil or sediment. Model projections tend to estimate losses of carbon in line with empirical measurements, but

Comparison of winter wheat yield sensitivity to climate variables under irrigated and rain-fed conditions

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Xiao, Dengpan; Shen, Yanjun; Zhang, He; Moiwo, Juana P.; Qi, Yongqing; Wang, Rende; Pei, Hongwei; Zhang, Yucui; Shen, Huitao

2016-09-01

Crop simulation models provide alternative, less time-consuming, and cost-effective means of determining the sensitivity of crop yield to climate change. In this study, two dynamic mechanistic models, CERES (Crop Environment Resource Synthesis) and APSIM (Agricultural Production Systems Simulator), were used to simulate the yield of wheat ( Triticum aestivum L.) under well irrigated (CFG) and rain-fed (YY) conditions in relation to different climate variables in the North China Plain (NCP). The study tested winter wheat yield sensitivity to different levels of temperature, radiation, precipitation, and atmospheric carbon dioxide (CO2) concentration under CFG and YY conditions at Luancheng Agro-ecosystem Experimental Stations in the NCP. The results from the CERES and APSIM wheat crop models were largely consistent and suggested that changes in climate variables influenced wheat grain yield in the NCP. There was also significant variation in the sensitivity of winter wheat yield to climate variables under different water (CFG and YY) conditions. While a temperature increase of 2°C was the threshold beyond which temperature negatively influenced wheat yield under CFG, a temperature rise exceeding 1°C decreased winter wheat grain yield under YY. A decrease in solar radiation decreased wheat grain yield under both CFG and YY conditions. Although the sensitivity of winter wheat yield to precipitation was small under the CFG, yield decreased significantly with decreasing precipitation under the rainfed YY treatment. The results also suggest that wheat yield under CFG linearly increased by ≈3.5% per 60 ppm (parts per million) increase in CO2 concentration from 380 to 560 ppm, and yield under YY increased linearly by ≈7.0% for the same increase in CO2 concentration.

Ecuador’s Mangrove Forest Carbon Stocks: A Spatiotemporal Analysis of Living Carbon Holdings and Their Depletion since the Advent of Commercial Aquaculture

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2015-01-01

In this paper we estimate the living carbon lost from Ecuador’s mangrove forests since the advent of export-focused shrimp aquaculture. We use remote sensing techniques to delineate the extent of mangroves and aquaculture at approximately decadal periods since the arrival of aquaculture in each Ecuadorian estuary. We then spatiotemporally calculate the carbon values of the mangrove forests and estimate the amount of carbon lost due to direct displacement by aquaculture. Additionally, we calculate the new carbon stocks generated due to mangrove reforestation or afforestation. This research introduces time and LUCC (land use / land cover change) into the tropical forest carbon literature and examines forest carbon loss at a higher spatiotemporal resolution than in many earlier analyses. We find that 80 percent, or 7,014,517 t of the living carbon lost in Ecuadorian mangrove forests can be attributed to direct displacement of mangrove forests by shrimp aquaculture. We also find that IPCC (Intergovernmental Panel on Climate Change) compliant carbon grids within Ecuador’s estuaries overestimate living carbon levels in estuaries where substantial LUCC has occurred. By approaching the mangrove forest carbon loss question from a LUCC perspective, these findings allow for tropical nations and other intervention agents to prioritize and target a limited set of land transitions that likely drive the majority of carbon losses. This singular cause of transition has implications for programs that attempt to offset or limit future forest carbon losses and place value on forest carbon or other forest good and services. PMID:25738286

AUTOMATIC CONTROL SYSTEM OF WINTER AUTOMOBILE-ROAD MAINTENANCE

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I. I. Leonovich

2008-01-01

Full Text Available In order to ensure a rational usage of financial and material resources directed on winter automobile-road maintenance in theRepublicofBelarusan automatic control system of winter maintenance is under its development and introduction.  The main purpose of the system is to obtain and use meteorological information on the state of a road network that allows to take necessary organizational and technological solutions ensuring safety and continuity of traffic during winter. This system also presupposes to ensure constant control over the state of roadway covering, expenditure of anti-glazed frost materials at all levels of management.The paper considers main aspects pertaining to introduction of the automatic control system of winter maintenance

Postharvest tillage reduces Downy Brome infestations in winter wheat

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In the Pacific Northwest, downy brome continues to infest winter wheat producing regions especially in low-rainfall areas where the winter wheat-summer fallow rotation is the dominate production system. In Washington, a study was conducted for 2 years at each of two locations in the winter wheat -su...

Extreme ozone depletion in the 2010–2011 Arctic winter stratosphere as observed by MIPAS/ENVISAT using a 2-D tomographic approach

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E. Arnone

2012-10-01

Full Text Available We present observations of the 2010–2011 Arctic winter stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS onboard ENVISAT. Limb sounding infrared measurements were taken by MIPAS during the Northern polar winter and into the subsequent spring, giving a continuous vertically resolved view of the Arctic dynamics, chemistry and polar stratospheric clouds (PSCs. We adopted a 2-D tomographic retrieval approach to account for the strong horizontal inhomogeneity of the atmosphere present under vortex conditions, self-consistently comparing 2011 to the 2-D analysis of 2003–2010. Unlike most Arctic winters, 2011 was characterized by a strong stratospheric vortex lasting until early April. Lower stratospheric temperatures persistently remained below the threshold for PSC formation, extending the PSC season up to mid-March, resulting in significant chlorine activation leading to ozone destruction. On 3 January 2011, PSCs were detected up to 30.5 ± 0.9 km altitude, representing the highest PSCs ever reported in the Arctic. Through inspection of MIPAS spectra, 83% of PSCs were identified as supercooled ternary solution (STS or STS mixed with nitric acid trihydrate (NAT, 17% formed mostly by NAT particles, and only two cases by ice. In the lower stratosphere at potential temperature 450 K, vortex average ozone showed a daily depletion rate reaching 100 ppbv day⁻¹. In early April at 18 km altitude, 10% of vortex measurements displayed total depletion of ozone, and vortex average values dropped to 0.6 ppmv. This corresponds to a chemical loss from early winter greater than 80%. Ozone loss was accompanied by activation of ClO, associated depletion of its reservoir ClONO₂, and significant denitrification, which further delayed the recovery of ozone in spring. Once the PSC season halted, ClO was reconverted primarily into ClONO₂. Compared to MIPAS observed 2003–2010 Arctic average values

How to Have a Healthy Winter | Poster

Science.gov (United States)

Without a doubt, winter is here. Between the icy weather and the recent hustle and bustle of the holidays, everyone is at an increased risk of getting sick. With that in mind, Occupational Health Services has a few simple tips for staying healthy this winter.

Risk management model of winter navigation operations

International Nuclear Information System (INIS)

Valdez Banda, Osiris A.; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub

2016-01-01

The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish–Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. - Highlights: •A model to assess and manage the risk of winter navigation operations is proposed. •The risks of oil spills in winter navigation in the Gulf of Finland are analysed. •The model assesses and prioritizes actions to control the risk of the operations. •The model suggests navigational training as the most efficient risk control option.

Drought and Winter Drying (Pest Alert)

Science.gov (United States)

USDA Forest Service

Drought and winter drying have periodically caused major damage to trees. Drought reduces the amount of water available in the soil. In the case of winter drying, the water may be in the soil, but freezing of the soil makes the water unavailable to the tree. In both cases, more water is lost through transpiration than is available to the plant. Symptoms of drought and...

Effects of winter military training on energy balance, whole-body protein balance, muscle damage, soreness, and physical performance.

Science.gov (United States)

Margolis, Lee M; Murphy, Nancy E; Martini, Svein; Spitz, Marissa G; Thrane, Ingjerd; McGraw, Susan M; Blatny, Janet-Martha; Castellani, John W; Rood, Jennifer C; Young, Andrew J; Montain, Scott J; Gundersen, Yngvar; Pasiakos, Stefan M

2014-12-01

Physiological consequences of winter military operations are not well described. This study examined Norwegian soldiers (n = 21 males) participating in a physically demanding winter training program to evaluate whether short-term military training alters energy and whole-body protein balance, muscle damage, soreness, and performance. Energy expenditure (D2(18)O) and intake were measured daily, and postabsorptive whole-body protein turnover ([(15)N]-glycine), muscle damage, soreness, and performance (vertical jump) were assessed at baseline, following a 4-day, military task training phase (MTT) and after a 3-day, 54-km ski march (SKI). Energy intake (kcal·day(-1)) increased (P balance was lower (P military training provide the basis for future studies to evaluate nutritional strategies that attenuate protein loss and sustain performance during severe energy deficits.

Soil respiration and carbon loss relationship with temperature and land use conversion in freeze-thaw agricultural area.

Science.gov (United States)

Ouyang, Wei; Lai, Xuehui; Li, Xia; Liu, Heying; Lin, Chunye; Hao, Fanghua

2015-11-15

Soil respiration (Rs) was hypothesized to have a special response pattern to soil temperature and land use conversion in the freeze-thaw area. The Rs differences of eight types of land use conversions during agricultural development were observed and the impacts of Rs on soil organic carbon (SOC) loss were assessed. The land use conversions during last three decades were categorized into eight types, and the 141 SOC sampling sites were grouped by conversion type. The typical soil sampling sites were subsequently selected for monitoring of soil temperature and Rs of each land use conversion types. The Rs correlations with temperature at difference depths and different conversion types were identified with statistical analysis. The empirical mean error model and the biophysical theoretical model with Arrhenius equation about the Rs sensitivity to temperature were both analyzed and shared the similar patterns. The temperature dependence of soil respiration (Q10) analysis further demonstrated that the averaged value of eight types of land use in this freeze-thaw agricultural area ranged from 1.15 to 1.73, which was lower than the other cold areas. The temperature dependence analysis demonstrated that the Rs in the top layer of natural land covers was more sensitive to temperature and experienced a large vertical difference. The natural land covers exhibited smaller Rs and the farmlands had the bigger value due to tillage practices. The positive relationships between SOC loss and Rs were identified, which demonstrated that Rs was the key chain for SOC loss during land use conversion. The spatial-vertical distributions of SOC concentration with the 1.5-km grid sampling showed that the more SOC loss in the farmland, which was coincided with the higher Rs in farmlands. The analysis of Rs dynamics provided an innovative explanation for SOC loss in the freeze-thaw agricultural area. The analysis of Rs dynamics provided an innovative explanation for SOC loss in the freeze

Loss of deuterium in faecal solids and by sequestration in reindeer: effect on doubly labelled water studies

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Geir Gotaas

2000-03-01

Full Text Available An underlying assumption when estimating total energy expenditure (TEE using doubly labelled water (DLW is that the injected isotopes (lsO and 2H leave the body only in the form of CO, and H20. However, both isotopes have additional routes of loss. We quantified the loss of 2H (i attached to faecal solids and (ii by sequestration into newly synthesised fat in reindeer (Rangifer tarandus tarandus. Estimates of the errors caused by these processes were applied to data from DLW studies with reindeer in summer and in winter. Given the net rate of faecal dry matter output and lipid synthesis in the present study, ignoring both sources of error caused the TEE of reindeer to be underestimated by approximately 5% in winter and approximately 9% in summer. The separate effect of each source of error was evaluated in summer. If ignored, loss of 2H through sequestration alone caused TEE to be underestimated by approximately 3.7%. Similarly, if ignored, loss of 2H attached to faecal solids alone caused TEE to be underestimated by approximately 5.9%.

Global characteristics of extreme winters from a multi-millennial simulation

Energy Technology Data Exchange (ETDEWEB)

Hunt, B.G. [CSIRO Marine and Atmospheric Research, PO Box 1, Aspendale (Australia)

2011-10-15

Output from a multi-millennial simulation with the CSIRO Mark 2 coupled global climatic model has been analysed to determine the principal characteristics of extreme winters over the globe for ''present conditions''. Thus, this study is not concerned with possible changes in winter conditions associated with anthropogenically induced climatic change. Defining an extreme winter as having a surface temperature anomaly of below -2 standard deviations (sd) revealed a general occurrence rate over the globe of between 100 and 200 over a 6,000-year period of the simulation, with somewhat higher values over northwest North America. For temperature anomalies below -3 sd the corresponding occurrence rate drops to about 10. Spatial correlation studies revealed that extreme winters over regions in Europe, North America or Asia were very limited geographically, with time series of the surface temperature anomalies for these regions having mutual correlation coefficients of about 0.2. The temporal occurrence rates of winters (summers) having sd below -3 (above +3) were very asymmetric and sporadic, suggesting that such events arise from stochastic influences. Multi-year sequences of extreme winters were comparatively rare events. Detailed analysis revealed that the temporal and spatial evolution of the monthly surface temperature anomalies associated with an individual extreme winter were well replicated in the simulation, as were daily time series of such anomalies. Apart from an influence of the North Atlantic Oscillation on extreme winters in Europe, other prominent climatic oscillations were very poorly correlated with such winters. Rather modest winter temperature anomalies were found in the southern hemisphere. (orig.)

Modeling and calculation of open carbon dioxide refrigeration system

International Nuclear Information System (INIS)

Cai, Yufei; Zhu, Chunling; Jiang, Yanlong; Shi, Hong

2015-01-01

Highlights: • A model of open refrigeration system is developed. • The state of CO 2 has great effect on Refrigeration capacity loss by heat transfer. • Refrigeration capacity loss by remaining CO 2 has little relation to the state of CO 2 . • Calculation results are in agreement with the test results. - Abstract: Based on the analysis of the properties of carbon dioxide, an open carbon dioxide refrigeration system is proposed, which is responsible for the situation without external electricity unit. A model of open refrigeration system is developed, and the relationship between the storage environment of carbon dioxide and refrigeration capacity is conducted. Meanwhile, a test platform is developed to simulation the performance of the open carbon dioxide refrigeration system. By comparing the theoretical calculations and the experimental results, several conclusions are obtained as follows: refrigeration capacity loss by heat transfer in supercritical state is much more than that in two-phase region and the refrigeration capacity loss by remaining carbon dioxide has little relation to the state of carbon dioxide. The results will be helpful to the use of open carbon dioxide refrigeration

On the relation between ionospheric winter anomalies and solar wind

International Nuclear Information System (INIS)

Rumi, G.C.

2001-01-01

There are two different winter anomalies. A small one that appears in connection with ionization at relatively low latitudes in the bottom of the D-region of the ionosphere. There, the electron densities in the winter happen to be less than should be expected. On the other hand, the classic winter anomaly is present when in the winter the upper D-region, again at relatively low latitudes, has more ionization than should be expected. Both these effects are due to the slant compression of the geomagnetic field produced by the solar wind in the wind in the winter season (which is, of course, the summer season when reference is made to events in the other hemisphere). It is shown that the small winter anomaly is a consequence of a hemispheric imbalance in the flux of galactic cosmic rays determined by the obliquely distorted geomagnetic field. It is shown that the standard winter anomaly can be ascribed to the influx of a super solar wind, which penetrates into the Earth's polar atmosphere down to E-region, heights and, duly concentrated through a funneling action at the winter pole of the distorted geomagnetic field, slows down the winter polar vortex. An equatorward motion of the polar air with its content of nitric oxide brings about the excess of ionization in the upper D-region at lower latitudes. The experimentally observed rhythmic recurrence of the upper winter anomaly is correlated to a possible rhythmic recurrence of the super solar wind. The actual detection of the upper winter anomaly could yield some information on the velocity of the basic solar wind. A by-product of the present analysis, the determination of Γ, the coefficient of collisional detachment of the electrons from the O 2 - ions, is presented in the Appendix

On the relation between ionospheric winter anomalies and solar wind

Energy Technology Data Exchange (ETDEWEB)

Rumi, G.C. [Lecco, (Italy)

2001-06-01

There are two different winter anomalies. A small one that appears in connection with ionization at relatively low latitudes in the bottom of the D-region of the ionosphere. There, the electron densities in the winter happen to be less than should be expected. On the other hand, the classic winter anomaly is present when in the winter the upper D-region, again at relatively low latitudes, has more ionization than should be expected. Both these effects are due to the slant compression of the geomagnetic field produced by the solar wind in the wind in the winter season (which is, of course, the summer season when reference is made to events in the other hemisphere). It is shown that the small winter anomaly is a consequence of a hemispheric imbalance in the flux of galactic cosmic rays determined by the obliquely distorted geomagnetic field. It is shown that the standard winter anomaly can be ascribed to the influx of a super solar wind, which penetrates into the Earth's polar atmosphere down to E-region, heights and, duly concentrated through a funneling action at the winter pole of the distorted geomagnetic field, slows down the winter polar vortex. An equatorward motion of the polar air with its content of nitric oxide brings about the excess of ionization in the upper D-region at lower latitudes. The experimentally observed rhythmic recurrence of the upper winter anomaly is correlated to a possible rhythmic recurrence of the super solar wind. The actual detection of the upper winter anomaly could yield some information on the velocity of the basic solar wind. A by-product of the present analysis, the determination of {gamma}, the coefficient of collisional detachment of the electrons from the O{sub 2} {sup -} ions, is presented in the Appendix.