WorldWideScience

Sample records for warm atlantic water

  1. Warm Water Pathways in the Northeastern North Atlantic ACCE RAFOS Float Data Report

    National Research Council Canada - National Science Library

    Furey, Heather

    2001-01-01

    ...). The RAFOS float component of ACCE, entitled "Warm Water Pathways and Intergyre Exchange in the Northeastern North Atlantic", was designed to measure the warm water currents entering the northeastern...

  2. Effect of Warm Atlantic Waters on the Climate Anomalies in the West Arctic

    Directory of Open Access Journals (Sweden)

    A. N. Zolotokrylin

    2015-01-01

    Full Text Available Significant climatic changes of oceanic and atmospheric elements and a relation of them to the ocean surface winter anomalies in North Atlantic are analyzed in the paper. Periods of «warm» ocean (2002–2012 and «cold» ocean (1960–1970 were determined. Positive anomalies of the ocean surface temperature increase the ice-free water area and, correspondingly, decrease the ice-field area. As a result of such changes in a state of the ocean surface (open water and ice, surface air temperature rises, and, consequently, atmospheric pressure in central part of a given Arctic sector drops.

  3. Vulnerability of Southeast Greenland Glaciers to Warm Atlantic Water From Operation IceBridge and Ocean Melting Greenland Data

    Science.gov (United States)

    Millan, R.; Rignot, E.; Mouginot, J.; Wood, M.; Bjørk, A. A.; Morlighem, M.

    2018-03-01

    We employ National Aeronautics and Space Administration (NASA)'s Operation IceBridge high-resolution airborne gravity from 2016, NASA's Ocean Melting Greenland bathymetry from 2015, ice thickness from Operation IceBridge from 2010 to 2015, and BedMachine v3 to analyze 20 major southeast Greenland glaciers. The results reveal glacial fjords several hundreds of meters deeper than previously thought; the full extent of the marine-based portions of the glaciers; deep troughs enabling warm, salty Atlantic Water (AW) to reach the glacier fronts and melt them from below; and few shallow sills that limit the access of AW. The new oceanographic and topographic data help to fully resolve the complex pattern of historical ice front positions from the 1930s to 2017: glaciers exposed to AW and resting on retrograde beds have retreated rapidly, while glaciers perched on shallow sills or standing in colder waters or with major sills in the fjords have remained stable.

  4. Diving of great shearwaters (Puffinus gravis in cold and warm water regions of the South Atlantic Ocean.

    Directory of Open Access Journals (Sweden)

    Robert A Ronconi

    Full Text Available BACKGROUND: Among the most widespread seabirds in the world, shearwaters of the genus Puffinus are also some of the deepest diving members of the Procellariiformes. Maximum diving depths are known for several Puffinus species, but dive depths or diving behaviour have never been recorded for great shearwaters (P. gravis, the largest member of this genus. This study reports the first high sampling rate (2 s of depth and diving behaviour for Puffinus shearwaters. METHODOLOGY/PRINCIPAL FINDINGS: Time-depth recorders (TDRs were deployed on two female great shearwaters nesting on Inaccessible Island in the South Atlantic Ocean, recording 10 consecutive days of diving activity. Remote sensing imagery and movement patterns of 8 males tracked by satellite telemetry over the same period were used to identify probable foraging areas used by TDR-equipped females. The deepest and longest dive was to 18.9 m and lasted 40 s, but most (>50% dives were <2 m deep. Diving was most frequent near dawn and dusk, with <0.5% of dives occurring at night. The two individuals foraged in contrasting oceanographic conditions, one in cold (8 to 10°C water of the Sub-Antarctic Front, likely 1000 km south of the breeding colony, and the other in warmer (10 to 16°C water of the Sub-tropical Frontal Zone, at the same latitude as the colony, possibly on the Patagonian Shelf, 4000 km away. The cold water bird spent fewer days commuting, conducted four times as many dives as the warm water bird, dived deeper on average, and had a greater proportion of bottom time during dives. CONCLUSIONS/SIGNIFICANCE: General patterns of diving activity were consistent with those of other shearwaters foraging in cold and warm water habitats. Great shearwaters are likely adapted to forage in a wide range of oceanographic conditions, foraging mostly with shallow dives but capable of deep diving.

  5. Water mass spreading in the warm water sphere of the eastern subtropical North Atlantic. Wassermassenausbreitung in der Warmwassersphaere des subtropischen Nordostatlantiks

    Energy Technology Data Exchange (ETDEWEB)

    Stramma, L

    1984-01-01

    Geostrophic transports in the eastern subtropical North Atlantic computed from historic hydrographic data and recent CTD measurements show a mean transport in the subtropical gyre of 11(+-1.6) x 10/sup 6/m/sup 3/s/sup -1/ in the upper 1000 m between 35/sup 0/W and the African coast. The dynamic method was used in conjunction with a conservation of mass scheme to determine the level of no motion. This level lies at the 1200 m depth near the Azores and drops to 1500 m in the tropics. The main inflow enters south of the Azores as a relatively narrow current, turns southward at the latitude of Madeira and then widens. Three current bands transport the water southward. North of the Cape Verde Islands, the current turns westwards. This part of the North Equatorial Current extends more to the south in the upper 200 m than in the 200-800 m layer. The Portugal current, between the Azores and the Portuguese coast, which is thought by some authors to be strong, is seen here as a relatively weak flow. Maps of potential vorticity derived from smoothed density profiles are consistent with the general pattern of geostrophic transport. At 24/sup 0/N one third of the total geostrophic southward transport of the recirculation and one third of the temperature flux is transported in the eastern Atlantic east of 35/sup 0/W.

  6. Atlantic Warm Pool Trigger for the Younger Dryas Climate Event

    Science.gov (United States)

    Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.; Teneva, L. T.

    2011-12-01

    There is growing evidence that variability in the size and heat content of the tropical Atlantic Warm Pool impacts circum-North Atlantic climate via the Atlantic Multi-decadal Oscillation mode (Wang et al., 2008). The Atlantic Warm Pool spans the Gulf of Mexico, Caribbean Sea and the western tropical North Atlantic. Barbados is located near the center of the tropical Atlantic Warm Pool and coupled ocean models suggest that Barbados remains near the center of the tropical Atlantic Warm Pool under varying wind stress simulations. Measurements of the oxygen isotope paleothermometer in Acropora palmata coral species recovered from cores offshore Barbados, show a 3oC monotonic decrease in sea surface temperature from 13106 ± 83 to 12744 ± 61 years before present (errors given as 2 sigma). This interval corresponds to a sea level rise from 71.4 meters to 67.1 meters below present levels at Barbados. The 3oC temperature decrease is captured in eight A. palmata specimens that are in stratigraphic sequence, 230Th/234U dated, and analyzed for oxygen isotopes. All measurements are replicated. We are confident that this is the warm pool equivalent of the Younger Dryas climate event. The initiation of this temperature drop in the Atlantic Warm Pool predates the Younger Dryas start in Greenland ice cores, reported to start at 12896 ± 138 years (relative to AD 2000) (Rasmussen et al., 2006), while few other Younger Dryas climate records are dated with similar accuracy to make the comparison. Rasmussen, S.O., Andersen, K.K., Svensson, A.M., Steffensen, J.P., Vinther, B.M., Clausen, H.B., Siggaard-Andersen, M.L., Johnsen, S.J., Larsen, L.B., Dahl-Jensen, D., Bigler, M., Röthlisberger, R., Fischer, H., Goto-Azuma, K., Hansson, M.E., and Ruth, U., 2006, A new Greenland ice core chronology for the last glacial termination: J. Geophys. Res., v. 111, p. D06102. Wang, C., Lee, S.-K., and Enfield, D.B., 2008, Atlantic Warm Pool acting as a link between Atlantic Multidecadal

  7. Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-02-03

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

  9. Coherent Multidecadal Atmospheric and Oceanic Variability in the North Atlantic: Blocking Corresponds with Warm Subpolar Ocean

    Science.gov (United States)

    Hakkinen, Sirpa M.; Rhines, P. B.; Worthen, D. L.

    2012-01-01

    Winters with frequent atmospheric blocking, in a band of latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean. This is evident in atmospheric reanalysis data, both modern and for the full 20th century. Blocking is approximately in phase with Atlantic multidecadal ocean variability (AMV). Wintertime atmospheric blocking involves a highly distorted jetstream, isolating large regions of air from the westerly circulation. It influences the ocean through windstress-curl and associated air/sea heat flux. While blocking is a relatively high-frequency phenomenon, it is strongly modulated over decadal timescales. The blocked regime (weaker ocean gyres, weaker air-sea heat flux, paradoxically increased transport of warm subtropical waters poleward) contributes to the warm phase of AMV. Atmospheric blocking better describes the early 20thC warming and 1996-2010 warm period than does the NAO index. It has roots in the hemispheric circulation and jet stream dynamics. Subpolar Atlantic variability covaries with distant AMOC fields: both these connections may express the global influence of the subpolar North Atlantic ocean on the global climate system.

  10. Fewer bacteria in warm water

    International Nuclear Information System (INIS)

    Bagh, Lene

    1999-01-01

    There has been many suggestions to how the ideal warm water system should be. Particularly whether warm water containers or heat exchangers in larger houses are the best solutions in order to maintain a water quality with low levels of bacteria. In an investigation made by Statens Byggeforskningsinstitutt (Denmark) regarding ''Bacterial growth in warm water installations with heat exchangers'' there were used several heat exchangers made by Gjelsted and Lund of three of which had HWAT heating cables. The bacterial content was low from these exchangers compared to exchangers with circulation. The article presents promising results from a study where the method was investigated over a longer period in two new larger warm water systems. Some energy conservation aspects are discussed

  11. Linking The Atlantic Gyres: Warm, Saline Intrusions From Subtropical Atlantic to the Nordic Seas

    Science.gov (United States)

    Hakkinen, Sirpa M.; Rhines, P. B.

    2010-01-01

    Ocean state estimates from SODA assimilation are analyzed to understand how major shifts in the North Atlantic Current path relate to AMOC, and how these shifts are related to large scale ocean circulation and surface forcing. These complement surface-drifter and altimetry data showing the same events. SODA data indicate that the warm water limb of AMOC, reaching to at least 600m depth, expanded in density/salinity space greatly after 1995, and that Similar events occurred in the late 1960s and around 1980. While there were large changes in the upper limb, there was no immediate response in the dense return flow, at least not in SODA, however one would expect a delayed response of increasing AMOC due to the positive feedback from increased salt transport. These upper limb changes are winddriven, involving changes in the eastern subpolar gyre, visible in the subduction of low potential vorticity waters. The subtropical gyre has been weak during the times of the northward intrusions of the highly saline subtropical waters, while the NAO index has been neutral or in a negative phase. The image of subtropical/subpolar gyre exchange through teleconnections within the AMOC overturning cell will be described.

  12. Warm and Saline Events Embedded in the Meridional Circulation of the Northern North Atlantic

    Science.gov (United States)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2011-01-01

    Ocean state estimates from 1958 to 2005 from the Simple Ocean Assimilation System (SODA) system are analyzed to understand circulation between subtropical and subpolar Atlantic and their connection with atmospheric forcing. This analysis shows three periods (1960s, around 1980, and 2000s) with enhanced warm, saline waters reaching high latitudes, alternating with freshwater events originating at high latitudes. It complements surface drifter and altimetry data showing the subtropical -subpolar exchange leading to a significant temperature and salinity increase in the northeast Atlantic after 2001. The warm water limb of the Atlantic meridional overturning cell represented by SODA expanded in density/salinity space during these warm events. Tracer simulations using SODA velocities also show decadal variation of the Gulf Stream waters reaching the subpolar gyre and Nordic seas. The negative phase of the North Atlantic Oscillation index, usually invoked in such variability, fails to predict the warming and salinization in the early 2000s, with salinities not seen since the 1960s. Wind stress curl variability provided a linkage to this subtropical/subpolar gyre exchange as illustrated using an idealized two ]layer circulation model. The ocean response to the modulation of the climatological wind stress curl pattern was found to be such that the northward penetration of subtropical tracers is enhanced when amplitude of the wind stress curl is weaker than normal. In this case both the subtropical and subpolar gyres weaken and the subpolar density surfaces relax; hence, the polar front moves westward, opening an enhanced northward access of the subtropical waters in the eastern boundary current.

  13. Arctic warming will promote Atlantic-Pacific fish interchange

    DEFF Research Database (Denmark)

    Wisz, Mary; Broennimann, O.; Grønkjær, Peter

    2015-01-01

    the interchange of marine biota between the two seas. Here, we forecast the potential northward progression of 515 fish species following climate change, and report the rate of potential species interchange between the Atlantic and the Pacific via the Northwest Passage and the Northeast Passage. For this, we...... projected niche-based models under climate change scenarios and simulated the spread of species through the passages when climatic conditions became suitable. Results reveal a complex range of responses during this century, and accelerated interchange after 2050. By 2100 up to 41 species could enter......Throughout much of the Quaternary Period, inhospitable environmental conditions above the Arctic Circle have been a formidable barrier separating most marine organisms in the North Atlantic from those in the North Pacific. Rapid warming has begun to lift this barrier, potentially facilitating...

  14. An anatomy of the projected North Atlantic warming hole in CMIP5 models

    Science.gov (United States)

    Menary, Matthew B.; Wood, Richard A.

    2018-04-01

    Global mean surface air temperature has increased over the past century and climate models project this trend to continue. However, the pattern of change is not homogeneous. Of particular interest is the subpolar North Atlantic, which has cooled in recent years and is projected to continue to warm less rapidly than the global mean. This is often termed the North Atlantic warming hole (WH). In climate model projections, the development of the WH is concomitant with a weakening of the Atlantic meridional overturning circulation (AMOC). Here, we further investigate the possible link between the AMOC and WH and the competing drivers of vertical mixing and surface heat fluxes. Across a large ensemble of 41 climate models we find that the spatial structure of the WH varies considerably from model to model but is generally upstream of the simulated deep water formation regions. A heat budget analysis suggests the formation of the WH is related to changes in ocean heat transport. Although the models display a plethora of AMOC mean states, they generally predict a weakening and shallowing of the AMOC also consistent with the evolving depth structure of the WH. A lagged regression analysis during the WH onset phase suggests that reductions in wintertime mixing lead a weakening of the AMOC by 5 years in turn leading initiation of the WH by 5 years. Inter-model differences in the evolution and structure of the WH are likely to lead to somewhat different projected climate impacts in nearby Europe and North America.

  15. Warming in the Nordic Seas, North Atlantic storms and thinning Arctic sea ice

    Science.gov (United States)

    Alexeev, Vladimir A.; Walsh, John E.; Ivanov, Vladimir V.; Semenov, Vladimir A.; Smirnov, Alexander V.

    2017-08-01

    Arctic sea ice over the last few decades has experienced a significant decline in coverage both in summer and winter. The currently warming Atlantic Water layer has a pronounced impact on sea ice in the Nordic Seas (including the Barents Sea). More open water combined with the prevailing atmospheric pattern of airflow from the southeast, and persistent North Atlantic storms such as the recent extremely strong Storm Frank in December 2015, lead to increased energy transport to the high Arctic. Each of these storms brings sizeable anomalies of heat to the high Arctic, resulting in significant warming and slowing down of sea ice growth or even melting. Our analysis indicates that the recently observed sea ice decline in the Nordic Seas during the cold season around Svalbard, Franz Joseph Land and Novaya Zemlya, and the associated heat release from open water into the atmosphere, contributed significantly to the increase in the downward longwave radiation throughout the entire Arctic. Added to other changes in the surface energy budget, this increase since the 1960s to the present is estimated to be at least 10 W m-2, which can result in thinner (up to at least 15-20 cm) Arctic ice at the end of the winter. This change in the surface budget is an important contributing factor accelerating the thinning of Arctic sea ice.

  16. Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11.

    Science.gov (United States)

    Kandiano, Evgenia S; van der Meer, Marcel T J; Schouten, Stefan; Fahl, Kirsten; Sinninghe Damsté, Jaap S; Bauch, Henning A

    2017-04-10

    Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.

  17. Pathways of warm water to the Northeast Greenland outlet glaciers

    Science.gov (United States)

    Schaffer, Janin; Timmermann, Ralph; Kanzow, Torsten; Arndt, Jan Erik; Mayer, Christoph; Schauer, Ursula

    2015-04-01

    The ocean plays an important role in modulating the mass balance of the Greenland Ice Sheet by delivering heat to the marine-terminating outlet glaciers surrounding the Greenland coast. The warming and accumulation of Atlantic Water in the subpolar North Atlantic has been suggested to be a potential driver of the glaciers' retreat over the last decades. The shelf regions thus play a critical role for the transport of Atlantic Water towards the glaciers, but also for the transfer of freshwater towards the deep ocean. A key region for the mass balance of the Greenland Ice Sheet is the Northeast Greenland Ice Stream. This large ice stream drains the second-largest basin of the Greenland Ice Sheet and feeds three outlet glaciers. The largest one is Nioghalvfjerdsfjorden (79°N-Glacier) featuring an 80 km long floating ice tongue. Both the ocean circulation on the continental shelf off Northeast Greenland and the circulation in the cavity below the ice tongue are weakly constrained so far. In order to study the relevant processes of glacier-ocean interaction we combine observations and model work. Here we focus on historic and recent hydrographic observations and on the complex bathymetry in the Northeast Greenland shelf region, which is thought to steer the flux of warm Atlantic water onto the continental shelf and into the sub-ice cavity beneath the 79°N-Glacier. We present a new global topography data set, RTopo-2, which includes the most recent surveys on the Northeast Greenland continental shelf and provides a detailed bathymetry for all around Greenland. In addition, RTopo-2 contains ice and bedrock surface topographies for Greenland and Antarctica. Based on the updated ocean bathymetry and a variety of hydrographic observations we show the water mass distribution on the continental shelf off Northeast Greenland. These maps enable us to discuss possible supply pathways of warm modified Atlantic waters on the continental shelf and thus potential ways of heat

  18. ON THE INFLUENCE OF GLOBAL WARMING ON ATLANTIC HURRICANE FREQUENCY

    Directory of Open Access Journals (Sweden)

    S. R. Hosseini

    2018-04-01

    Full Text Available In this paper, the possible connection between the frequency of Atlantic hurricanes to the climate change, mainly the variation in the Atlantic Ocean surface temperature has been investigated. The correlation between the observed hurricane frequency for different categories of hurricane’s intensity and Sea Surface Temperature (SST has been examined over the Atlantic Tropical Cyclogenesis Regions (ACR. The results suggest that in general, the frequency of hurricanes have a high correlation with SST. In particular, the frequency of extreme hurricanes with Category 5 intensity has the highest correlation coefficient (R = 0.82. In overall, the analyses in this work demonstrates the influence of the climate change condition on the Atlantic hurricanes and suggest a strong correlation between the frequency of extreme hurricanes and SST in the ACR.

  19. On the Influence of Global Warming on Atlantic Hurricane Frequency

    Science.gov (United States)

    Hosseini, S. R.; Scaioni, M.; Marani, M.

    2018-04-01

    In this paper, the possible connection between the frequency of Atlantic hurricanes to the climate change, mainly the variation in the Atlantic Ocean surface temperature has been investigated. The correlation between the observed hurricane frequency for different categories of hurricane's intensity and Sea Surface Temperature (SST) has been examined over the Atlantic Tropical Cyclogenesis Regions (ACR). The results suggest that in general, the frequency of hurricanes have a high correlation with SST. In particular, the frequency of extreme hurricanes with Category 5 intensity has the highest correlation coefficient (R = 0.82). In overall, the analyses in this work demonstrates the influence of the climate change condition on the Atlantic hurricanes and suggest a strong correlation between the frequency of extreme hurricanes and SST in the ACR.

  20. Property Changes of Abyssal Waters in the Western Tropical Atlantic

    Science.gov (United States)

    Herrford, Josefine; Brandt, Peter; Zenk, Walter

    2017-04-01

    Flowing northward towards the equator, Antarctic Bottom Water (AABW) encounters the lighter overlying North Atlantic Deep Water (NADW), both water masses creating an abyssal stratification and gradually mixing across their interface. Changes in the associated water mass formation and/or along-path transformation, observable in the evolution of water mass volume and characteristics, might impact the deep oceans uptake of anthropogenic CO2 or its contribution to global sea level rise. We compile historic and recent shipboard measurements of hydrography and velocity to provide a comprehensive view on water mass distribution, pathways, along-path transformation and long-term temperature changes of abyssal waters in the western South and Equatorial Atlantic. We are able to confirm previous results showing that the northwest corner of the Brazil Basin represents a splitting point for the southward/northward flow of NADW/AABW. The available measurements sample water mass transformation along the two major routes for deep and bottom waters in the tropical to South Atlantic - along the deep western boundary and eastward, parallel to the equator - as well as the hot spots of extensive mixing. We find lower NADW and lighter AABW to form a highly interactive transition layer in the northern Brazil Basin. The AABW north of 5°S is relatively homogeneous with only lighter AABW being able to pass through the Equatorial Channel (EQCH) into the North Atlantic. Spanning a period of 26 years, our data also allow an estimation of long-term temperature trends in abyssal waters. We find a warming of 2.5 ± 0.7•10-3 °C yr-1 of the waters in the northern Brazil Basin being colder than 0.6 °C throughout the period 1989-2014 and can relate that warming to a thinning of the dense AABW layer. While isopycnal heave is the dominant effect defining the vertical distribution of temperature trends on isobars, we also find temperature changes on isopycnals in the transition layer the lower NADW

  1. The Atmospheric Response to a Future Warming Deficit in North Atlantic SSTs

    Science.gov (United States)

    Gervais, M.; Shaman, J. L.; Kushnir, Y.

    2017-12-01

    As SSTs increase globally over the 21st century, global climate models project a significant deficit in warming within the subpolar gyre of the North Atlantic Ocean. This study investigates the impact of this warming deficit on atmosphere circulation. A series of large ensemble experiments are conducted using the Community Atmosphere Model 5 forced with specified sea ice and SSTs for the early (2010-2019), mid (2050-2059), and late (2090-2099) 21stcentury. SST and sea ice fields from the Community Earth System Model Large Ensemble experiment are used as boundary conditions for the control simulations. Experiments with either a filled or deepened warming hole are conducted by adding a SST perturbation field to these time-varying SST boundary conditions. Results from these experiments demonstrate that the warming hole has significant local and remote impacts on the atmosphere. Filling (deepening) the warming hole results in a local increase (decrease) in turbulent heat fluxes relative to the control run and consequentially an increase (decrease) in temperature in the overlying lower troposphere that spreads over Europe. There are significant impacts on the location and strength of both the North Atlantic and North Pacific jets as well as on the North Atlantic Oscillation. These impacts of the warming hole on both the mean state and variability of the atmosphere have important implications for sensible weather in the Northern Hemisphere and in particular over Europe.

  2. Reduced interdecadal variability of Atlantic Meridional Overturning Circulation under global warming.

    Science.gov (United States)

    Cheng, Jun; Liu, Zhengyu; Zhang, Shaoqing; Liu, Wei; Dong, Lina; Liu, Peng; Li, Hongli

    2016-03-22

    Interdecadal variability of the Atlantic Meridional Overturning Circulation (AMOC-IV) plays an important role in climate variation and has significant societal impacts. Past climate reconstruction indicates that AMOC-IV has likely undergone significant changes. Despite some previous studies, responses of AMOC-IV to global warming remain unclear, in particular regarding its amplitude and time scale. In this study, we analyze the responses of AMOC-IV under various scenarios of future global warming in multiple models and find that AMOC-IV becomes weaker and shorter with enhanced global warming. From the present climate condition to the strongest future warming scenario, on average, the major period of AMOC-IV is shortened from ∼50 y to ∼20 y, and the amplitude is reduced by ∼60%. These reductions in period and amplitude of AMOC-IV are suggested to be associated with increased oceanic stratification under global warming and, in turn, the speedup of oceanic baroclinic Rossby waves.

  3. Late Holocene Radiocarbon Variability in Northwest Atlantic Slope Waters

    Energy Technology Data Exchange (ETDEWEB)

    Sherwood, O; Edinger, E; Guilderson, T P; Ghaleb, B; Risk, M J; Scott, D B

    2008-08-15

    Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post bomb-{sup 14}C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb {Delta}{sup 14}C signature (-67 {+-} 4{per_thousand}) to at least 1000 m depth. Surface water bomb-{sup 14}C signals were lagged and damped (peaking at {approx} +45{per_thousand} in the early 1980s) relative to other regions of the northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in {Delta}{sup 14}C is much stronger. In surface water, pre-bomb {Delta}{sup 14}C averaged -75 {+-} 5{per_thousand}. At 250-475 m depth, prebomb {Delta}{sup 14}C oscillated quasi-decadally between -80 and -100{per_thousand}, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical {Delta}{sup 14}C gradients over the last 1200 years.

  4. Impact of the Atlantic Warm Pool on precipitation and temperature in Florida during North Atlantic cold spells

    Energy Technology Data Exchange (ETDEWEB)

    Donders, Timme H. [Utrecht University, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht (Netherlands); TNO Geological Survey of the Netherlands, Utrecht (Netherlands); Boer, Hugo Jan de; Dekker, Stefan C. [Utrecht University, Department of Environmental Sciences, Faculty of Geosciences, P.O. Box 80115, Utrecht (Netherlands); Finsinger, Walter; Wagner-Cremer, Friederike [Utrecht University, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Utrecht (Netherlands); Grimm, Eric C. [Research and Collections Center, Illinois State Museum, Springfield, IL (United States); Reichart, Gert Jan [Utrecht University, Geochemistry, Department of Earth Sciences, Faculty of Geosciences, P.O. Box 80021, Utrecht (Netherlands)

    2011-01-15

    Recurrent phases of increased pine at Lake Tulane, Florida have previously been related to strong stadials terminated by so-called Heinrich events. The climatic significance of these pine phases has been interpreted in different ways. Using a pollen-climate inference model, we quantified the climate changes and consistently found that mean summer precipitation (P{sub JJA}) increased (0.5-0.9 mm/day) and mean November temperature increased (2.0-3.0 C) during pine phases coeval with Heinrich events and the Younger Dryas. Marine sea surface temperature records indicate that potential sources for these moisture and heat anomalies are in the Gulf of Mexico and the western tropical Atlantic. We explain this low latitude warming by an increased Loop Current facilitated by persistence of the Atlantic Warm Pool during summer. This hypothesis is supported by a climate model sensitivity analysis. A positive heat anomaly in the Gulf of Mexico and equatorial Atlantic best approximates the pollen-inferred climate reconstructions from Lake Tulane during the (stadials around) Heinrich events and the Younger Dryas. (orig.)

  5. An observational study on the temperature rising effects in water warming canal and water warming pond

    Energy Technology Data Exchange (ETDEWEB)

    Hong, J. B.; Hong, S. B. [Rural Development Cooperation, Seoul (Korea, Republic of)

    1990-09-15

    The power water flowed out from the multipurpose darn influences the ecosystem approximately because of the low water temperature. An appropriate counter measure to the rising water temperature is needed for growing crops especially when the temperature is below 18°C in the source of the irrigation water This observational study is practiced in Yong-Doo water warming canal and pond in the down stream of Choong-Ju multipurpose dam and is practiced for analyse and compare the rising effects in actural water temperature by actual measurement with the rising effects of planned water temperatuer by the basic theoritical method and for the help to present the direction in plan establishment through investigate the results afterwards. The results are as follows. 1. The degree of the rise of the water temperature can be decided by θ{sub x} = θ{sub 0} + K (L/(v * h)) * (T - θ{sub 0}) Then, K values of a factor representing the characteristics of the water warming canal were 0.00002043 for the type I. and 0.0000173 for the type II. respectively. 2. A variation of water temperature which produced by the difference effective temperature and water temperature in the water warming canal was θ{sub x1} = 16.5 + 15.9 (1-e{sup -0.00018x}), θ{sub x2} = 18.8 + 8.4(1-e{sup -0.000298x}) for the type I. and θ{sub x} = 19.6 + 12.8 (1-e{sup -0.00041x}) for the type II. 3. It was shown that the effects of the rise of water temperature for the type I. water warming canal were greater than that of type II. as a resultes of broadening the surface of the canal compared with the depth of water, coloring the surface of water canal and installing the resistance block. 4. In case of the type I. water warming canal, the equation between the air temperature and the degree of the rise of water temprature could be made; Y = 0.4134X + 7.728 In addition, in case of the type II. water warming canal, the correlation was very low. 5. A monthly variation of the water temperature in the water warming

  6. Antarctic Bottom Water temperature changes in the western South Atlantic from 1989 to 2014

    Science.gov (United States)

    Johnson, Gregory C.; McTaggart, Kristene E.; Wanninkhof, Rik

    2014-12-01

    Warming of abyssal waters in recent decades contributes to global heat uptake and sea level rise. Repeat oceanographic section data in the western South Atlantic taken mostly in 1989 (1995 across the Scotia Sea), 2005, and 2014 are used to quantify warming in abyssal waters that spread northward through the region from their Antarctic origins in the Weddell Sea. While much of the Scotia Sea warmed between 1995 and 2005, only the southernmost portion, on the north side of the Weddell Gyre, continued to warm between 2005 and 2014. The abyssal Argentine Basin also warmed between 1989 and 2005, but again only the southernmost portion continued to warm between 2005 and 2014, suggesting a slowdown in the inflow of the coldest, densest Antarctic Bottom Waters into the western South Atlantic between 1989 and 2014. In contrast, the abyssal waters of the Brazil Basin warmed both between 1989 and 2005 and between 2005 and 2014, at a rate of about 2 m°C yr-1. This warming is also assessed in terms of the rates of change of heights above the bottom for deep isotherms in each deep basin studied. These results, together with findings from previous studies, suggest the deep warming signal observed in the Weddell Sea after the mid-1970s Weddell Polynya was followed by abyssal warming in the Argentine Basin from the late 1970s through about 2005, then warming in the deep Vema Channel from about 1992 through at least 2010, and warming in the Brazil Basin from 1989 to 2014.

  7. Moisture transport from the Atlantic to the Pacific basin and its response to North Atlantic cooling and global warming

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Ingo [University of Hawaii at Manoa, International Pacific Research Center, Honolulu, HI (United States); Xie, Shang-Ping [University of Hawaii at Manoa, Department of Meteorology, Honolulu, HI (United States)

    2010-08-15

    Atmospheric moisture transport from the Atlantic to the Pacific basin plays an important role in regulating North Atlantic salinity and thus the strength of the thermohaline circulation. Potential changes in the strength of this moisture transport are investigated for two different climate-change scenarios: North Atlantic cooling representative of Heinrich events, and increased greenhouse gas (GHG) forcing. The effect of North Atlantic cooling is studied using a coupled regional model with comparatively high resolution that successfully simulates Central American gap winds and other important aspects of the region. Cooler North Atlantic sea surface temperature (SST) in this model leads to a regional decrease of atmospheric moisture but also to an increase in wind speed across Central America via an anomalous pressure gradient. The latter effect dominates, resulting in a 0.13 Sv (1 Sv = 10{sup 6} m{sup 3} s{sup -1}) increase in overall moisture transport to the Pacific basin. In fresh water forcing simulations with four different general circulation models, the wind speed effect is also present but not strong enough to completely offset the effect of moisture decrease except in one model. The influence of GHG forcing is studied using simulations from the Intergovernmental Panel on Climate Change archive. In these simulations atmospheric moisture increases globally, resulting in an increase of moisture transport by 0.25 Sv from the Atlantic to Pacific. Thus, in both scenarios, moisture transport changes act to stabilize the thermohaline circulation. The notion that the Andes effectively block moisture transport from the Atlantic to the Pacific basin is not supported by the simulations and atmospheric reanalyses examined here. This indicates that such a blocking effect does not exist or else that higher resolution is needed to adequately represent the steep orography of the Andes. (orig.)

  8. The Danish fish fauna during the warm Atlantic period (ca. 7000-3900 bc): Forerunner of future changes?

    DEFF Research Database (Denmark)

    Enghoff, I.B.; MacKenzie, Brian; Eg Nielsen, Einar

    2007-01-01

    Vast amounts of fish bone lie preserved in Denmark's soil as remains of prehistoric fishing. Fishing was particularly important during the Atlantic period (ca. 7000-3900 bc, i.e. part of the Mesolithic Stone Age). At this time, sea temperature and salinity were higher in waters around Denmark than...... today. Analyses of more than 100,000 fish bones from various settlements from this period document which fish species were common in coastal Danish waters at this time. This study provides a basis for comparing the fish fauna in the warm Stone Age sea with the tendencies seen and predicted today...... frequently caught species in the Danish Stone Age sea. These results demonstrate that major changes to the fish fauna near Denmark will occur as climate changes. However, exploitable cod populations can potentially be maintained in waters near Denmark, including the North Sea, but the vulnerability...

  9. Twentieth century North Atlantic climate change. Part II: Understanding the effect of Indian Ocean warming

    Energy Technology Data Exchange (ETDEWEB)

    Hoerling, M.P.; Xu, T.; Bates, G.T. [Climate Diagnostics Center NOAA, Boulder, CO 80305-3328 (United States); Hurrell, J.W.; Phillips, A.S. [National Center for Atmospheric Research, Boulder, CO (United States)

    2004-09-01

    Ensembles of atmospheric general circulation model (AGCM) experiments are used in an effort to understand the boreal winter Northern Hemisphere (NH) extratropical climate response to the observed warming of tropical sea surface temperatures (SSTs) over the last half of the twentieth Century. Specifically, we inquire about the origins of unusual, if not unprecedented, changes in the wintertime North Atlantic and European climate that are well described by a linear trend in most indices of the North Atlantic Oscillation (NAO). The simulated NH atmospheric response to the linear trend component of tropic-wide SST change since 1950 projects strongly onto the positive polarity of the NAO and is a hemispheric pattern distinguished by decreased (increased) Arctic (middle latitude) sea level pressure. Progressive warming of the Indian Ocean is the principal contributor to this wintertime extratropical response, as shown through additional AGCM ensembles forced with only the SST trend in that sector. The Indian Ocean influence is further established through the reproducibility of results across three different models forced with identical, idealized patterns of the observed warming. Examination of the transient atmospheric adjustment to a sudden ''switch-on'' of an Indian Ocean SST anomaly reveals that the North Atlantic response is not consistent with linear theory and most likely involves synoptic eddy feedbacks associated with changes in the North Atlantic storm track. The tropical SST control exerted over twentieth century regional climate underlies the importance of determining the future course of tropical SST for regional climate change and its uncertainty. Better understanding of the extratropical responses to different, plausible trajectories of the tropical oceans is key to such efforts. (orig.)

  10. Global Warming In A Regional Model of The Atlantic Ocean - Echam4/opyc3 In Flame 4/3

    Science.gov (United States)

    Schweckendiek, U.; Willebrand, J.

    The reaction of the Thermohaline Circulation (THC) in most climate models on global warming scenarios is a weakening of the THC. An exception is the ECHAM4/OPYC3 simulation whose stable behaviour is traced back to a strongly enhanced evaporation and as a consequence to a development of a salt anomaly in the tropics and subtropics of the Atlantic Ocean (Latif et al.,2000). This salt signal is advected into convection regions and compensates the reduction of surface density due to surface heating and freshening. To examine this scenario for a more realistic ocean model, data from this model is used to drive a reginal model of the Atlantic Ocean. In order to test the crucial mechanisms for the maintainance of the meridional overturning, we have performed sensitivity studies by focussing on different combinations of the anomalous freshwater and heat fluxes. The results demonstrate that for the stabilising effect to become effective the salt sig- nal has to enter the GIN-Seas and subsequently the overflow waters, underlining the importance of the overflows for the THC. The Labrador Sea Convection is however uneffected by this stabilising salt signal and its convection ultimatly breaks down un- der surface warming and freshening.

  11. Warm water upwelling in the Cenozoic Era

    Science.gov (United States)

    Zhang, Y.

    2017-12-01

    Modern observations show that the occurrence of wind-driven upwelling is often tied to cold sea surface temperatures (SSTs). However, SST reconstructions indicate that globally, the upwelling regions were much warmer in the Miocene and Pliocene. This questions the overall strength of deep-water upwelling in the geological past, with important implications for the associated atmospheric, climatic and biogeochemical processes, and the fate of upwelling regions in a high-CO2 world. We recently showed that the eastern equatorial Pacific (EEP) was characterized by strong air-sea disequilibrium of CO2 during the late Miocene - Pliocene. Combined with export productivity proxies, we interpreted these as signs of vigorous upwelling. The upwelled waters were nutrient- and CO2-rich, but warm. The cause of the "excess" warming in the upwelling regions is linked to the source waters which originated from the higher latitudes. In other words, the reduced east (upwelling) to west (non-upwelling) temperature gradients along the equator in major ocean basins are rooted in the reduced meridional temperature gradients. To further test this hypothesis, we examine the history of the EEP and temperature gradients during the even-warmer Eocene - middle Miocene.

  12. Uses of warmed water in agriculture. Final report

    International Nuclear Information System (INIS)

    Garrett, R.E.

    1978-11-01

    Energy in the form of warmed water is available from condenser cooling water from fossil fuel or nuclear-electric power-generating facilities, geothermal power plants, geothermal fluids, or spent steam and cooling water from industrial processes. A re-analysis of the characteristics of possible agricultural uses of warmed water has revealed the need to decouple considerations of warmed water sources from those of warmed water users. Conflicting objectives and managerial requirements seem to preclude an integrated system approach. Rather an interface must be established with separate costs and benefits identified for a reliable warmed water source and for its various potential uses. These costs and benefits can be utilized as a basis for decisions separately by the energy supplier and the prospective energy users. A method of classifying uses of warmed water according to need, volume, objective, temperature, and quality is presented and preliminary classifications are discussed for several potential agricultural uses of warmed water. Specific uses for soil warming, space heating in greenhouses, and irrigation are noted. Specific uses in aquaculture for catfish, lobster, and prawn production are discussed. Warmed water use in animal shelters is mentioned. Low-quality heat is required for methane generation from biomass and warmed water heating could be utilized in this industry. 53 references

  13. Reduced interdecadal variability of Atlantic Meridional Overturning Circulation under global warming

    Science.gov (United States)

    Cheng, Jun; Liu, Zhengyu; Zhang, Shaoqing; Liu, Wei; Dong, Lina; Liu, Peng; Li, Hongli

    2016-01-01

    Interdecadal variability of the Atlantic Meridional Overturning Circulation (AMOC-IV) plays an important role in climate variation and has significant societal impacts. Past climate reconstruction indicates that AMOC-IV has likely undergone significant changes. Despite some previous studies, responses of AMOC-IV to global warming remain unclear, in particular regarding its amplitude and time scale. In this study, we analyze the responses of AMOC-IV under various scenarios of future global warming in multiple models and find that AMOC-IV becomes weaker and shorter with enhanced global warming. From the present climate condition to the strongest future warming scenario, on average, the major period of AMOC-IV is shortened from ∼50 y to ∼20 y, and the amplitude is reduced by ∼60%. These reductions in period and amplitude of AMOC-IV are suggested to be associated with increased oceanic stratification under global warming and, in turn, the speedup of oceanic baroclinic Rossby waves. PMID:26951654

  14. Water Availability in a Warming World

    Science.gov (United States)

    Aminzade, Jennifer

    As climate warms during the 21st century, the resultant changes in water availability are a vital issue for society, perhaps even more important than the magnitude of warming itself. Yet our climate models disagree in their forecasts of water availability, limiting our ability to plan accordingly. This thesis investigates future water availability projections from Coupled Ocean-Atmosphere General Circulation Models (GCMs), primarily using two water availability measures: soil moisture and the Supply Demand Drought Index (SDDI). Chapter One introduces methods of measuring water availability and explores some of the fundamental differences between soil moisture, SDDI and the Palmer Drought Severity Index (PDSI). SDDI and PDSI tend to predict more severe future drought conditions than soil moisture; 21st century projections of SDDI show conditions rivaling North American historic mega-droughts. We compare multiple potential evapotranspiration (EP) methods in New York using input from the GISS Model ER GCM and local station data from Rochester, NY, and find that they compare favorably with local pan evaporation measurements. We calculate SDDI and PDSI values using various EP methods, and show that changes in future projections are largest when using EP methods most sensitive to global warming, not necessarily methods producing EP values with the largest magnitudes. Chapter Two explores the characteristics and biases of the five GCMs and their 20th and 21st century climate projections. We compare atmospheric variables that drive water availability changes globally, zonally, and geographically among models. All models show increases in both dry and wet extremes for SDDI and soil moisture, but increases are largest for extreme drying conditions using SDDI. The percentage of gridboxes that agree on the sign of change of soil moisture and SDDI between models is very low, but does increase in the 21st century. Still, differences between models are smaller than differences

  15. Response of the Water Cycle of West Africa and Atlantic to Radiative Forcing by Saharan Dust

    Science.gov (United States)

    Lau, K. M.; Kim, Kyu-Myong; Sud, Yogesh C.; Walker, Gregory L.

    2010-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence in support of the "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summer, as a result of large-scale atmospheric feed back triggered by absorbing dust aerosols, rainfall and cloudiness are enhanced over the West Africa/Easter Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean. region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while long wave has the opposite response. The elevated dust layer warms the air over Nest Africa and the eastern Atlantic. The condensation heating associated with the induced deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface energy fluxes, resulting in cooling of the Nest African land and the eastern Atlantic, and a warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at 0.95 or higher.

  16. Tides, the PIG, and 'warm' water

    International Nuclear Information System (INIS)

    Robertson, Robin

    2010-01-01

    The present rapid melting of the Pine Island Glacier (PIG) has been attributed to basal melting driven by the ocean. Specifically, this ocean melting is attributed to currents and tides pumping 'warm' Circumpolar Deep Water (CDW) into the ice shelf cavity. To identify tidal activity in the region, an observational time series of yo-yo CTD (Conductivity, Temperature, and Depth) data collected in the PIG outflow region was analyzed. The water column in front of the PIG consisted of two primary layers, a meltwater layer exiting the ice shelf cavity over a layer of CDW. Semidiurnal tides were present in both layers, with both the strength and direction of the tides differing between the two layers. The upper layer tides were stronger and directed in and out of the cavity, while the lower layer tides were primarily directed along the front of the cavity. Energy was found to be transferred from the semidiurnal tide to other frequencies and to be reflected by the ice shelf front. These mechanisms were most prominent at the interfaces between layers and indicate potential mixing between the layers. In conclusion, tides were found to contribute to the circulation into the ice shelf cavity and also to mixing of the exiting water, which influences pumping of the CDW into the ice shelf cavity and melting of the PIG.

  17. The role of the subtropical North Atlantic water cycle in recent US extreme precipitation events

    Science.gov (United States)

    Li, Laifang; Schmitt, Raymond W.; Ummenhofer, Caroline C.

    2018-02-01

    The role of the oceanic water cycle in the record-breaking 2015 warm-season precipitation in the US is analyzed. The extreme precipitation started in the Southern US in the spring and propagated northward to the Midwest and the Great Lakes in the summer of 2015. This seasonal evolution of precipitation anomalies represents a typical mode of variability of US warm-season precipitation. Analysis of the atmospheric moisture flux suggests that such a rainfall mode is associated with moisture export from the subtropical North Atlantic. In the spring, excessive precipitation in the Southern US is attributable to increased moisture flux from the northwestern portion of the subtropical North Atlantic. The North Atlantic moisture flux interacts with local soil moisture which enables the US Midwest to draw more moisture from the Gulf of Mexico in the summer. Further analysis shows that the relationship between the rainfall mode and the North Atlantic water cycle has become more significant in recent decades, indicating an increased likelihood of extremes like the 2015 case. Indeed, two record-high warm-season precipitation events, the 1993 and 2008 cases, both occurred in the more recent decades of the 66 year analysis period. The export of water from the North Atlantic leaves a marked surface salinity signature. The salinity signature appeared in the spring preceding all three extreme precipitation events analyzed in this study, i.e. a saltier-than-normal subtropical North Atlantic in spring followed by extreme Midwest precipitation in summer. Compared to the various sea surface temperature anomaly patterns among the 1993, 2008, and 2015 cases, the spatial distribution of salinity anomalies was much more consistent during these extreme flood years. Thus, our study suggests that preseason salinity patterns can be used for improved seasonal prediction of extreme precipitation in the Midwest.

  18. Interdecadal Trichodesmium variability in cold North Atlantic waters

    Science.gov (United States)

    Rivero-Calle, Sara; Del Castillo, Carlos E.; Gnanadesikan, Anand; Dezfuli, Amin; Zaitchik, Benjamin; Johns, David G.

    2016-11-01

    Studies of the nitrogen cycle in the ocean generally assume that the distribution of the marine diazotroph, Trichodesmium, is restricted to warm, tropical, and subtropical oligotrophic waters. Here we show evidence that Trichodesmium are widely distributed in the North Atlantic. We report an approximately fivefold increase during the 1980s and 1990s in Trichodesmium presence near the British Isles with respect to the average over the last 50 years. A potential explanation is an increase in the Saharan dust source starting in the 1980s, coupled with changes in North Atlantic winds that opened a pathway for dust transport. Results from a coarse-resolution model in which winds vary but iron deposition is climatologically fixed suggest frequent nitrogen limitation in the region and reversals of the Portugal current, but it does not simulate the observed changes in Trichodesmium. Our results suggest that Trichodesmium may be capable of growth at temperatures below 20°C and challenge assumptions about their latitudinal distribution. Therefore, we need to reevaluate assumptions about the temperature limitations of Trichodesmium and the dinitrogen (N2) fixation capabilities of extratropical strains, which may have important implications for the global nitrogen budget.

  19. Coral mucus fuels the sponge loop in warm- and cold-water coral reef ecosystems.

    Science.gov (United States)

    Rix, Laura; de Goeij, Jasper M; Mueller, Christina E; Struck, Ulrich; Middelburg, Jack J; van Duyl, Fleur C; Al-Horani, Fuad A; Wild, Christian; Naumann, Malik S; van Oevelen, Dick

    2016-01-07

    Shallow warm-water and deep-sea cold-water corals engineer the coral reef framework and fertilize reef communities by releasing coral mucus, a source of reef dissolved organic matter (DOM). By transforming DOM into particulate detritus, sponges play a key role in transferring the energy and nutrients in DOM to higher trophic levels on Caribbean reefs via the so-called sponge loop. Coral mucus may be a major DOM source for the sponge loop, but mucus uptake by sponges has not been demonstrated. Here we used laboratory stable isotope tracer experiments to show the transfer of coral mucus into the bulk tissue and phospholipid fatty acids of the warm-water sponge Mycale fistulifera and cold-water sponge Hymedesmia coriacea, demonstrating a direct trophic link between corals and reef sponges. Furthermore, 21-40% of the mucus carbon and 32-39% of the nitrogen assimilated by the sponges was subsequently released as detritus, confirming a sponge loop on Red Sea warm-water and north Atlantic cold-water coral reefs. The presence of a sponge loop in two vastly different reef environments suggests it is a ubiquitous feature of reef ecosystems contributing to the high biogeochemical cycling that may enable coral reefs to thrive in nutrient-limited (warm-water) and energy-limited (cold-water) environments.

  20. Warming of the Global Ocean: Spatial Structure and Water-Mass Trends

    Science.gov (United States)

    Hakkinen, Sirpa; Rhines, Peter B.; Worthen, Denise L.

    2016-01-01

    This study investigates the multidecadal warming and interannual-to-decadal heat content changes in the upper ocean (0-700 m), focusing on vertical and horizontal patterns of variability. These results support a nearly monotonic warming over much of the World Ocean, with a shift toward Southern Hemisphere warming during the well-observed past decade. This is based on objectively analyzed gridded observational datasets and on a modeled state estimate. Besides the surface warming, a warming climate also has a subsurface effect manifesting as a strong deepening of the midthermocline isopycnals, which can be diagnosed directly from hydrographic data. This deepening appears to be a result of heat entering via subduction and spreading laterally from the high-latitude ventilation regions of subtropical mode waters. The basin-average multidecadal warming mainly expands the subtropical mode water volume, with weak changes in the temperature-salinity (u-S) relationship (known as ''spice'' variability). However, the spice contribution to the heat content can be locally large, for example in Southern Hemisphere. Multidecadal isopycnal sinking has been strongest over the southern basins and weaker elsewhere with the exception of the Gulf Stream/North Atlantic Current/subtropical recirculation gyre. At interannual to decadal time scales, wind-driven sinking and shoaling of density surfaces still dominate ocean heat content changes, while the contribution from temperature changes along density surfaces tends to decrease as time scales shorten.

  1. Intermediate report on the problems of warm water drainage

    International Nuclear Information System (INIS)

    1976-01-01

    The investigation into the solution of the problems of warm water drainage and its related matters was conducted, and the result was summarized by the warm water drainage sectional committee of the central public nuisance-prevention council entrusted by the Environment Agency. The first section of this report deals with the background of the warm water drainage problems. In December 1970, the environmental pollution prevention act was revised so as to include warm water drainage in the law. The second section deals with the progress of deliberation by the sectional committee. The third section deals with the actual conditions of warm water drainage. The temperature difference at the inlet and outlet of water was 5 to 11 0 C in power plants, 5 to 16 0 C in iron and steel works, 4 to 11 0 C in petroleum refineries, and 7 to 25 0 C in petrochemical plants. The amount of heat energy discharged from power plants was greater than that from the others. Other sections deal with its effects on the living things in water, the forecast of diffusion of warm drainage, the concept of the regulation of warm drainage, and the present countermeasure. Twelve points which require future investigation are listed. They are the change in the phases of living things affected by the change in temperature and flow of warm drainage, the effects on fishery resources, the estimation system for the environmental calorific capacity in the sea, the mechanism of diffusion and the forecasting method for the diffusion range. (Iwakiri, K.)

  2. Sea-ice cover in the Nordic Seas and the sensitivity to Atlantic water temperatures

    Science.gov (United States)

    Jensen, Mari F.; Nisancioglu, Kerim H.; Spall, Michael A.

    2017-04-01

    Changes in the sea-ice cover of the Nordic Seas have been proposed to play a key role for the dramatic temperature excursions associated with the Dansgaard-Oeschger events during the last glacial. However, with its proximity to the warm Atlantic water, how a sea-ice cover can persist in the Nordic Seas is not well understood. In this study, we apply an eddy-resolving configuration of the Massachusetts Institute of Technology general circulation model with an idealized topography to study the presence of sea ice in a Nordic Seas-like domain. We assume an infinite amount of warm Atlantic water present in the south by restoring the southern area to constant temperatures. The sea-surface temperatures are restored toward cold, atmospheric temperatures, and as a result, sea ice is present in the interior of the domain. However, the sea-ice cover in the margins of the Nordic Seas, an area with a warm, cyclonic boundary current, is sensitive to the amount of heat entering the domain, i.e., the restoring temperature in the south. When the temperature of the warm, cyclonic boundary current is high, the margins are free of sea ice and heat is released to the atmosphere. We show that with a small reduction in the temperature of the incoming Atlantic water, the Nordic Seas-like domain is fully covered in sea ice. Warm water is still entering the Nordic Seas, however, this happens at depths below a cold, fresh surface layer produced by melted sea ice. Consequently, the heat release to the atmosphere is reduced along with the eddy heat fluxes. Results suggest a threshold value in the amount of heat entering the Nordic Seas before the sea-ice cover disappears in the margins. We study the sensitivity of this threshold to changes in atmospheric temperatures and vertical diffusivity.

  3. Interannual to Decadal Variability of Atlantic Water in the Nordic and Adjacent Seas

    Science.gov (United States)

    Carton, James A.; Chepurin, Gennady A.; Reagan, James; Haekkinen, Sirpa

    2011-01-01

    Warm salty Atlantic Water is the main source water for the Arctic Ocean and thus plays an important role in the mass and heat budget of the Arctic. This study explores interannual to decadal variability of Atlantic Water properties in the Nordic Seas area where Atlantic Water enters the Arctic, based on a reexamination of the historical hydrographic record for the years 1950-2009, obtained by combining multiple data sets. The analysis shows a succession of four multi-year warm events where temperature anomalies at 100m depth exceed 0.4oC, and three cold events. Three of the four warm events lasted 3-4 years, while the fourth began in 1999 and persists at least through 2009. This most recent warm event is anomalous in other ways as well, being the strongest, having the broadest geographic extent, being surface-intensified, and occurring under exceptional meteorological conditions. Three of the four warm events were accompanied by elevated salinities consistent with enhanced ocean transport into the Nordic Seas, with the exception of the event spanning July 1989-July 1993. Of the three cold events, two lasted for four years, while the third lasted for nearly 14 years. Two of the three cold events are associated with reduced salinities, but the cold event of the 1960s had elevated salinities. The relationship of these events to meteorological conditions is examined. The results show that local surface heat flux variations act in some cases to reinforce the anomalies, but are too weak to be the sole cause.

  4. Amplified North Atlantic Warming in the Late Pliocene by Changes in Arctic Gateways

    Science.gov (United States)

    Otto-Bliesner, B. L.; Jahn, A.; Feng, R.; Brady, E. C.; Hu, A.; Lofverstrom, M.

    2017-12-01

    Reconstructions of the late Pliocene (mid-Piacenzian, 3.3 - 3.0 million years ago) sea surface temperature (SST) find much warmer conditions in the North Atlantic than modern. The much warmer SSTs, up to 8.8°C from sites with good dating and replicates from several different types of proxies, have been difficult for climate models to reproduce. Even with the slow feedbacks of a reduced Greenland ice sheet and expansion of boreal forests to the Arctic Ocean over Canada and Eurasia, models cannot warm the North Atlantic sufficiently to match the reconstructed SSTs. An enhancement of the Atlantic Meridional Overturning Circulation (AMOC) during the late Pliocene, proposed as a possible mechanism based on ocean core records of δ13C, also is not present in the model simulations. Here, we present CESM simulations using a new reconstruction of late Pliocene paleogeography that has the Bering Strait (BS) and Canadian Arctic Archipelago (CAA) Straits closed. We find that the closure of these small Arctic gateways strengthens the AMOC, by inhibiting freshwater (FW) transport from the Pacific to the Arctic Ocean and from the Arctic Ocean to the Labrador Sea, leading to warmer sea surface temperatures in the North Atlantic. The cutoff of the short export route through the CAA results in a more saline Labrador and south Greenland Sea with increased deep convection. At the same time, as all FW now leaves the Arctic east of Greenland, there is a freshening of and decreased deepwater formation in the Norwegian Sea. Overall, the AMOC strengthens. This past time period has implications for a future Earth under more responsible scenarios of emissions. Late Pliocene atmospheric carbon dioxide concentrations are estimated to have ranged between 350 and 450 ppmv and the paleogeography is relatively similar to modern. Our study indicates that the state of the Arctic gateways may influence the sensitivity of the North Atlantic climate in complex ways, and better understanding of the

  5. Effects of Atlantic warm pool variability over climate of South America tropical transition zone

    Science.gov (United States)

    Ricaurte Villota, Constanza; Romero-Rodríguez, Deisy; Andrés Ordoñez-Zuñiga, Silvio; Murcia-Riaño, Magnolia; Coca-Domínguez, Oswaldo

    2016-04-01

    Colombia is located in the northwestern corner of South America in a climatically complex region due to the influence processes modulators of climate both the Pacific and Atlantic region, becoming in a transition zone between phenomena of northern and southern hemisphere. Variations in the climatic conditions of this region, especially rainfall, have been attributed to the influence of the El Nino Southern Oscillation (ENSO), but little is known about the interaction within Atlantic Ocean and specifically Caribbean Sea with the environmental conditions of this region. In this work We studied the influence of the Atlantic Warm Pool (AWP) on the Colombian Caribbean (CC) climate using data of Sea Surface Temperature (SST) between 1900 - 2014 from ERSST V4, compared with in situ data SIMAC (National System for Coral Reef Monitoring in Colombia - INVEMAR), rainfall between 1953-2013 of meteorological stations located at main airports in the Colombian Caribbean zone, administered by IDEAM, and winds data between 2003 - 2014 from WindSat sensor. The parameters analyzed showed spatial differences throughout the study area. SST anomalies, representing the variability of the AWP, showed to be associated with Multidecadal Atlantic Oscillation (AMO) and with the index of sea surface temperature of the North-tropical Atlantic (NTA), the variations was on 3 to 5 years on the ENSO scale and of approximately 11 years possibly related to solar cycles. Rainfall anomalies in the central and northern CC respond to changes in SST, while in the south zone these are not fully engage and show a high relationship with the ENSO. Finally, the winds also respond to changes in SST and showed a signal approximately 90 days possibly related to the Madden-Julian Oscillation, whose intensity depends on the CC region being analyzed. The results confirm that region is a transition zone in which operate several forcing, the variability of climate conditions is difficult to attribute only one, as ENSO

  6. Nonlinear Response of the Stratosphere and the North Atlantic-European Climate to Global Warming

    Science.gov (United States)

    Manzini, E.; Karpechko, A. Yu.; Kornblueh, L.

    2018-05-01

    The response of the northern winter atmospheric circulation for two consecutive global warming periods of 2 K is examined in a grand ensemble (68 members) of idealized CO2 increase experiments performed with the same climate model. The comparison of the atmospheric responses for the two periods shows remarkable differences, indicating the nonlinearity of the response. The nonlinear signature of the atmospheric and surface responses is reminiscent of the positive phase of the annular mode of variability. The stratospheric vortex response shifts from an easterly wind change for the first 2 K to a westerly wind change for the second 2 K. The North Atlantic storm track shifts poleward only in the second period. A weaker November Arctic amplification during the second period suggests that differences in Arctic sea ice changes can act to trigger the atmospheric nonlinear response. Stratosphere-troposphere coupling thereafter can provide for the persistence of this nonlinearity throughout the winter.

  7. The influence of the Atlantic Warm Pool on the Florida panhandle sea breeze

    Science.gov (United States)

    Misra, Vasubandhu; Moeller, Lauren; Stefanova, Lydia; Chan, Steven; O'Brien, James J.; Smith, Thomas J.; Plant, Nathaniel

    2011-01-01

    In this paper we examine the variations of the boreal summer season sea breeze circulation along the Florida panhandle coast from relatively high resolution (10 km) regional climate model integrations. The 23 year climatology (1979–2001) of the multidecadal dynamically downscaled simulations forced by the National Centers for Environmental Prediction–Department of Energy (NCEP-DOE) Reanalysis II at the lateral boundaries verify quite well with the observed climatology. The variations at diurnal and interannual time scales are also well simulated with respect to the observations. We show from composite analyses made from these downscaled simulations that sea breezes in northwestern Florida are associated with changes in the size of the Atlantic Warm Pool (AWP) on interannual time scales. In large AWP years when the North Atlantic Subtropical High becomes weaker and moves further eastward relative to the small AWP years, a large part of the southeast U.S. including Florida comes under the influence of relatively strong anomalous low-level northerly flow and large-scale subsidence consistent with the theory of the Sverdrup balance. This tends to suppress the diurnal convection over the Florida panhandle coast in large AWP years. This study is also an illustration of the benefit of dynamic downscaling in understanding the low-frequency variations of the sea breeze.

  8. Property changes of deep and bottom waters in the Western Tropical Atlantic

    Science.gov (United States)

    Herrford, Josefine; Brandt, Peter; Zenk, Walter

    2017-06-01

    The flow of North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) contributes to the Atlantic meridional overturning circulation. Changes in the associated water mass formation might impact the deep ocean's capacity to take up anthropogenic CO2 while a warming of the deep ocean significantly contributes to global sea level rise. Here we compile historic and recent shipboard measurements of hydrography and velocity to provide a comprehensive view of water mass distribution, pathways, along-path transformation and long-term temperature changes of NADW and AABW in the western South and Equatorial Atlantic. We confirm previous results which show that the northwest corner of the Brazil Basin represents a splitting point for the southward/northward flow of NADW/AABW. The available measurements sample water mass transformation along the two major routes for deep and bottom waters in the tropical to South Atlantic - along the deep western boundary and eastward, parallel to the equator - as well as the hot-spots of extensive mixing. We find lower NADW and lighter AABW to form a highly interactive transition layer in the northern Brazil Basin. The AABW north of 5°S is relatively homogeneous with only lighter AABW being able to pass through the Equatorial Channel (EQCH) into the North Atlantic. Spanning a period of 26 years, our data also allow an estimation of long-term temperature trends in abyssal waters. We find a warming of 2.5±0.7•10-3 °C yr-1 of the waters in the northern Brazil Basin at temperatures colder than 0.6 °C throughout the period 1989-2014 and can relate this warming to a thinning of the dense AABW layer. Whereas isopycnal heave is the dominant effect which defines the vertical distribution of temperature trends on isobars, we also find temperature changes on isopycnals in the lower NADW and AABW layers. There temperatures on isopycnals exhibit decadal variations with warming in the 1990s and cooling in the 2000s - the contributions to the

  9. Increased risk of a shutdown of ocean convection posed by warm North Atlantic summers

    Science.gov (United States)

    Oltmanns, Marilena; Karstensen, Johannes; Fischer, Jürgen

    2018-04-01

    A shutdown of ocean convection in the subpolar North Atlantic, triggered by enhanced melting over Greenland, is regarded as a potential transition point into a fundamentally different climate regime1-3. Noting that a key uncertainty for future convection resides in the relative importance of melting in summer and atmospheric forcing in winter, we investigate the extent to which summer conditions constrain convection with a comprehensive dataset, including hydrographic records that are over a decade in length from the convection regions. We find that warm and fresh summers, characterized by increased sea surface temperatures, freshwater concentrations and melting, are accompanied by reduced heat and buoyancy losses in winter, which entail a longer persistence of the freshwater near the surface and contribute to delaying convection. By shortening the time span for the convective freshwater export, the identified seasonal dynamics introduce a potentially critical threshold that is crossed when substantial amounts of freshwater from one summer are carried over into the next and accumulate. Warm and fresh summers in the Irminger Sea are followed by particularly short convection periods. We estimate that in the winter 2010-2011, after the warmest and freshest Irminger Sea summer on our record, 40% of the surface freshwater was retained.

  10. Temperature responses of tropical to warm temperate Cladophora species in relation to their distribution in the North Atlantic Ocean

    Science.gov (United States)

    Cambridge, M. L.; Breeman, A. M.; Kraak, S.; van den Hoek, C.

    1987-09-01

    The relationship between distribution boundaries and temperature responses of some North Atlantic Cladophora species (Chlorophyta) was experimentally examined under various regimes of temperature, light and daylength. Experimentally determined critical temperature intervals, in which survival, growth or reproduction was limited, were compared with annual temperature regimes (monthly means and extremes) at sites inside and outside distribution boundaries. The species tested belonged to two phytogeographic groups: (1) the tropical West Atlantic group ( C. submarina: isolate from Curaçao) and (2) the amphiatlantic tropical to warm temperate group ( C. prolifera: isolate from Corsica; C. coelothrix: isolates from Brittany and Curaçao; and C. laetevirens: isolates from deep and shallow water in Corsica and from Brittany). In accordance with distribution from tropical to warm temperate regions, each of the species grew well between 20 30°C and reproduction and growth were limited at and below 15°C. The upper survival limit in long days was <35°C in all species but high or maximum growth rates occurred at 30°C. C. prolifera, restricted to the tropical margins, had the most limited survival at 35°C. Experimental evidence suggests that C. submarina is restricted to the Caribbean and excluded from the more northerly American mainland and Gulf of Mexico coasts by sporadic low winter temperatures in the nearshore waters, when cold northerly weather penetrates far south every few years. Experimental evidence suggests that C. prolifera, C. coelothrix and C. laetevirens are restricted to their northern European boundaries by summer temperatures too low for sufficient growth and/or reproduction. Their progressively more northerly located boundaries were accounted for by differences in growth rates over the critical 10 15°C interval. C. prolifera and C. coelothrix are excluded or restricted in distribution on North Sea coasts by lethal winter temperatures, again differences

  11. Influence of Atlantic on the warming and reduction of sea ice in the Arctic

    Directory of Open Access Journals (Sweden)

    G. V. Alekseev

    2017-01-01

    Full Text Available Influence of anomalies of the sea surface temperature (SST in low latitudes of the North Atlantic on the sea ice cover and the near-surface air temperature in the marine Arctic is discussed in the article. Data on the SST in the Atlantic Ocean from the HadISST dataset, climatic series of the water temperature at the section along the Kola meridian together with mean monthly data on the sea ice extent and the air surface temperature in the Maritime Arctic and the Northern hemisphere were analyzed. Multivariate cross-correlation analysis was applied to determine the maximum correlation coefficients between the SST anomalies, climate characteristics and their corresponding delays within time limits of 33 to 38 months. Existence of intimate link had been found between changes of the Atlantic SST in low latitudes and the sea ice extent in the Arctic with correlation coefficients up to 0.90 and delays up to 3 years. A mechanism of formation of the remote influence of low-latitude SST anomalies on the sea ice anomalies in the Arctic Ocean is proposed. The interpretation of this mechanism includes into consideration the interaction between atmospheric and oceanic circulation modes.

  12. Thermal Niche Tracking and Future Distribution of Atlantic Mackerel Spawning in response to Ocean Warming

    Directory of Open Access Journals (Sweden)

    Antoine eBruge

    2016-06-01

    Full Text Available North-east Atlantic mackerel spawning distribution has shifted northward in the last three decades probably in response to global sea warming. Yet, uncertainties subsist regarding on the shift rate, causalities, and how this species will respond to future conditions. Using egg surveys, we explored the influence of temperature change on mackerel’s spawning distribution (western and southern spawning components of the stock between 1992 and 2013, and projected how it may change under future climate change scenarios. We developed three generalized additive models: (i a spatiotemporal model to reconstruct the spawning distribution for the north-east Atlantic stock over the period 1992-2013, to estimate the rate of shift; (ii a thermal habitat model to assess if spawning mackerel have tracked their thermal spawning-niche; and (iii a niche-based model to project future spawning distribution under two predicted climate change scenarios. Our findings showed that mackerel spawning activity has shifted northward at a rate of 15.9 ± 0.9 km/decade between 1992 and 2013. Similarly, using the thermal habitat model, we detected a northward shift of the thermal spawning-niche. This indicates that mackerel has spawned at higher latitudes to partially tracking their thermal spawning-niche, at a rate of 28.0 ± 9.0 km/°C of sea warming. Under future scenarios (mid and end of the century, the extrapolation of the niche-based model to coupled hydroclimatic and biogeochemical models indicates that centre of gravity of mackerel spawning distribution is expected to shift westward (32 to 117 km and northward (0.5 to 328 km, but with high variability according to scenarios and time frames. The future of the overall egg production in the area is uncertain (change from -9.3% to 12%. With the aim to allow the fishing industry to anticipate the future distribution of mackerel shoals during the spawning period, future research should focus on reducing uncertainty in

  13. Late Quaternary Hydroclimate of Arid Northeastern Mexico: Response of Millennial-scale Global Climate Change and the Atlantic Warm Pool

    Science.gov (United States)

    Roy, P. D.; Shanahan, T. M.; Sánchez Zavala, J. L.; Lozano-SantaCruz, R.; Vera-Vera, G.

    2017-12-01

    Model projections suggest that drought-prone northeastern Mexico could experience an increase of more than 2 ºC in mean annual temperature and precipitation could decrease at least by 10-20% over the 21st century. The combination of drought and warmth would enhance the dryness of this water-stressed region in the coming decades. However, because of the lack of long continuous records from the region, little is known about the past controls on climate variability in northeast Mexico. In order to better understand the susceptibility of this climatically sensitive but data-poor region, we present a new multi-proxy record of past hydrological changes from paleo-lacustrine deposits in the Sandia Basin ( 24°N) over the last 32 cal ka BP. We reconstruct runoff from changes in the abundance of Al-bearing clastic minerals and local hydrological changes from the oxygen isotope composition of lacustrine carbonates, as well as gypsum/calcite abundances. During the cooler Heinrich Stadials (HS3, HS2 and HS1) and Younger Dryas, the basin received less runoff and the lake was more saline, though hydrological conditions varied significantly throughout these stadial events. The wettest interval in the record occurred coincident with the Bølling-Allerød (B/A) interstadial. Arid conditions returned during the Holocene, with low sedimentation rates, reduced proxy runoff indicators, and enhanced gypsum deposition suggesting this was the driest interval of the last 30 ka. Our observations are consistent with a growing number of records from across both northeastern Mexico and the southern Great Plains suggesting dry conditions associated with North Atlantic stadials and a sudden but transient shift to wetter conditions accompanying the strengthening of the overturning circulation during the B/A. We will evaluate the possible influence of Atlantic Warm Pool on hydroclimate of the region by comparing the different proxy records to the sea-surface temperature of Gulf of Mexico

  14. Comparison of Distal Limb Warming With Fluidotherapy and Warm Water Immersion for Mild Hypothermia Rewarming.

    Science.gov (United States)

    Kumar, Parveen; McDonald, Gerren K; Chitkara, Radhika; Steinman, Alan M; Gardiner, Phillip F; Giesbrecht, Gordon G

    2015-09-01

    The purpose of the study was to determine the effectiveness of Fluidotherapy rewarming through the distal extremities for mildly hypothermic, vigorously shivering subjects. Fluidotherapy is a dry heat modality in which cellulose particles are suspended by warm air circulation. Seven subjects (2 female) were cooled on 3 occasions in 8˚C water for 60 minutes, or to a core temperature of 35°C. They were then dried and rewarmed in a seated position by 1) shivering only; 2) Fluidotherapy applied to the distal extremities (46 ± 1°C, mean ± SD); or 3) water immersion of the distal extremities (44 ± 1°C). The order of rewarming followed a balanced design. Esophageal temperature, skin temperature, heart rate, oxygen consumption, and heat flux were measured. The warm water produced the highest rewarming rate, 6.1°C·h(-1), 95% CI: 5.3-6.9, compared with Fluidotherapy, 2.2°C·h(-1), 95% CI: 1.4-3.0, and shivering only, 2.0°C·h(-1), 95% CI: 1.2-2.8. The Fluidotherapy and warm water conditions increased skin temperature and inhibited shivering heat production, thus reducing metabolic heat production (166 ± 42 W and 181 ± 45 W, respectively), compared with shivering only (322 ± 142 W). Warm water provided a significantly higher net heat gain (398.0 ± 52 W) than shivering only (288.4 ± 115 W). Fluidotherapy was not as effective as warm water for rewarming mildly hypothermic subjects. Although Fluidotherapy is more portable and technically simpler, it provides a lower rate of rewarming that is similar to shivering only. It does help decrease shivering heat production, lowering energy expenditure and cardiac work, and could be considered in a hospital setting, if convenient. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  15. The Once and Future North Atlantic: How the Mid-Pliocene Warm Period Can Increase Stakeholder Preparedness in a Warming World

    Science.gov (United States)

    Jacobs, P.; de Mutsert, K.

    2013-12-01

    Paleoclimatic reconstructions, particularly from periods that may serve as an analog to the present and future greenhouse-driven warming, are increasingly being used to validate climate models as well as to provide constraints on broad impacts such as global temperature and sea level change. However, paleoclimatic data remains under-utilized in decision-making processes by stakeholders, who typically rely on scenarios produced by computer models or naive extrapolation of present trends. We hope to increase the information available to stakeholders by incorporating paleoclimatic data from the mid-Pliocene Warm Period (mPWP, ~3ma) into a fisheries model of the North Atlantic. North Atlantic fisheries are economically important and are expected to be sensitive to climatic change. State of the art climate models remain unable to realistically simulate the North Atlantic, both over the observational record as well as during times in the geologic past such as the mPWP. Given that the mPWP shares many of the same boundary conditions as those likely to be seen in the near future, we seek to answer the question 'What if the climate of the future looks more like the climate of the past?' relative to what state of the art computer models currently project. To that end we have created a suite of future North Atlantic Ocean scenarios using output from the CMIP3 and CMIP5 modeling experiments, as well as the PRISM group's Mid-Pliocene ocean reconstruction. We use these scenarios to drive an ecosystem-based fisheries model using the Ecopath with Ecosim (EwE) software to identify differences between the scenarios as the North Atlantic Ocean changes through time. Additionally, we examine the spatial component of these differences by using the Ecospace module of EwE. Whereas the Ecosim realizations are intended to capture the dynamic response to changing oceanographic parameters (SST, SSS, DO) over time, the Ecospace experiments are intended to explore the impact of different

  16. Long-Term Precipitation Isotope Ratios (δ18O, δ2H, d-excess) in the Northeast US Reflect Atlantic Ocean Warming and Shifts in Moisture Sources

    Science.gov (United States)

    Puntsag, T.; Welker, J. M.; Mitchell, M. J.; Klein, E. S.; Campbell, J. L.; Likens, G.

    2014-12-01

    The global water cycle is exhibiting dramatic changes as global temperatures increase resulting in increases in: drought extremes, flooding, alterations in storm track patterns with protracted winter storms, and greater precipitation variability. The mechanisms driving these changes can be difficult to assess, but the spatial and temporal patterns of precipitation water isotopes (δ18O, δ2H, d-excess) provide a means to help understand these water cycle changes. However, extended temporal records of isotope ratios in precipitation are infrequent, especially in the US. In our study we analyzed precipitation isotope ratio data from the Hubbard Brook Experimental Forest in New Hampshire that has the longest US precipitation isotope record, to determine: 1) the monthly composited averages and trends from 1967 to 2012 (45 years); ; 2) the relationships between abiotic properties such as local temperatures, precipitation type, storm tracks and isotope ratio changes; and 3) the influence of regional shifts in moisture sources and/or changes in N Atlantic Ocean water conditions on isotope values. The seasonal variability of Hubbard Brook precipitation isotope ratios is consistent with other studies, as average δ18O values are ~ -15‰ in January and ~ -5 ‰ in July. However, over the 45 year record there is a depletion trend in the δ 18O values (becoming isotopically lighter with a greater proportion of 16O), which coupled with less change in δ 2H leads to increases in d-excess values from ~ -10‰ around 1970 to greater than 10‰ in 2009. These changes occurred during a period of warming as opposed to cooling local temperatures indicating other processes besides temperature are controlling long-term water isotope traits in this region. We have evidence that these changes in precipitation isotope traits are controlled in large part by an increases in moisture being sourced from a warming N Atlantic Ocean that is providing evaporated, isotopically

  17. Splitting of Atlantic water transport towards the Arctic Ocean into the Fram Strait and Barents Sea Branches - mechanisms and consequences

    Science.gov (United States)

    Beszczynska-Möller, Agnieszka; Skagseth, Øystein; von Appen, Wilken-Jon; Walczowski, Waldemar; Lien, Vidar

    2016-04-01

    The heat content in the Arctic Ocean is to a large extent determined by oceanic advection from the south. During the last two decades the extraordinary warm Atlantic water (AW) inflow has been reported to progress through the Nordic Seas into the Arctic Ocean. Warm anomalies can result from higher air temperatures (smaller heat loss) in the Nordic Seas, and/or from an increased oceanic advection. But the ultimate fate of warm anomalies of Atlantic origin depends strongly on their two possible pathways towards the Arctic Ocean. The AW temperature changes from 7-10°C at the entrance to the Nordic Seas, to 6-6.5°C in the Barents Sea opening and 3-3.5°C as the AW leaving Fram Strait enters the Arctic Ocean. When AW passes through the shallow Barents Sea, nearly all its heat is lost due to atmospheric cooling and AW looses its signature. In the deep Fram Strait the upper part of Atlantic water becomes transformed into a less saline and colder surface layer and thus AW preserves its warm core. A significant warming and high variability of AW volume transport was observed in two recent decades in the West Spitsbergen Current, representing the Fram Strait Branch of Atlantic inflow. The AW inflow through Fram Strait carries between 26 and 50 TW of heat into the Arctic Ocean. While the oceanic heat influx to the Barents Sea is of a similar order, the heat leaving it through the northern exit into the Arctic Ocean is negligible. The relative strength of two Atlantic water branches through Fram Strait and the Barents Sea governs the oceanic heat transport into the Arctic Ocean. According to recently proposed mechanism, the Atlantic water flow in the Barents Sea Branch is controlled by the strength of atmospheric low over the northern Barents Sea, acting through a wind-induced Ekman divergence, which intensifies eastward AW flow. The Atlantic water transport in the Fram Strait Branch is mainly forced by the large-scale low-pressure system over the eastern Norwegian and

  18. Understanding the causes of recent warming of mediterranean waters. How much could be attributed to climate change?

    Science.gov (United States)

    Macias, Diego; Garcia-Gorriz, Elisa; Stips, Adolf

    2013-01-01

    During the past two decades, Mediterranean waters have been warming at a rather high rate resulting in scientific and social concern. This warming trend is observed in satellite data, field data and model simulations, and affects both surface and deep waters throughout the Mediterranean basin. However, the warming rate is regionally different and seems to change with time, which has led to the question of what causes underlie the observed trends. Here, we analyze available satellite information on sea surface temperature (SST) from the last 25 years using spectral techniques and find that more than half of the warming tendency during this period is due to a non-linear, wave-like tendency. Using a state of the art hydrodynamic model, we perform a hindcast simulation and obtain the simulated SST evolution of the Mediterranean basin for the last 52 years. These SST results show a clear sinusoidal tendency that follows the Atlantic Multidecadal Oscillation (AMO) during the simulation period. Our results reveal that 58% of recent warming in Mediterranean waters could be attributed to this AMO-like oscillation, being anthropogenic-induced climate change only responsible for 42% of total trend. The observed acceleration of water warming during the 1990s therefore appears to be caused by a superimposition of anthropogenic-induced warming with the positive phase of the AMO, while the recent slowdown of this tendency is likely due to a shift in the AMO phase. It has been proposed that this change in the AMO phase will mask the effect of global warming in the forthcoming decades, and our results indicate that the same could also be applicable to the Mediterranean Sea. Henceforth, natural multidecadal temperature oscillations should be taken into account to avoid underestimation of the anthropogenic-induced warming of the Mediterranean basin in the future.

  19. Understanding the causes of recent warming of mediterranean waters. How much could be attributed to climate change?

    Directory of Open Access Journals (Sweden)

    Diego Macias

    Full Text Available During the past two decades, Mediterranean waters have been warming at a rather high rate resulting in scientific and social concern. This warming trend is observed in satellite data, field data and model simulations, and affects both surface and deep waters throughout the Mediterranean basin. However, the warming rate is regionally different and seems to change with time, which has led to the question of what causes underlie the observed trends. Here, we analyze available satellite information on sea surface temperature (SST from the last 25 years using spectral techniques and find that more than half of the warming tendency during this period is due to a non-linear, wave-like tendency. Using a state of the art hydrodynamic model, we perform a hindcast simulation and obtain the simulated SST evolution of the Mediterranean basin for the last 52 years. These SST results show a clear sinusoidal tendency that follows the Atlantic Multidecadal Oscillation (AMO during the simulation period. Our results reveal that 58% of recent warming in Mediterranean waters could be attributed to this AMO-like oscillation, being anthropogenic-induced climate change only responsible for 42% of total trend. The observed acceleration of water warming during the 1990s therefore appears to be caused by a superimposition of anthropogenic-induced warming with the positive phase of the AMO, while the recent slowdown of this tendency is likely due to a shift in the AMO phase. It has been proposed that this change in the AMO phase will mask the effect of global warming in the forthcoming decades, and our results indicate that the same could also be applicable to the Mediterranean Sea. Henceforth, natural multidecadal temperature oscillations should be taken into account to avoid underestimation of the anthropogenic-induced warming of the Mediterranean basin in the future.

  20. The role of meltwater-induced subsurface ocean warming in regulating the Atlantic meridional overturning in glacial climate simulations

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Esther C.; Otto-Bliesner, Bette L. [National Center for Atmospheric Research, Boulder, CO (United States)

    2011-10-15

    The Community Climate System Model version 3, (CCSM3) is used to investigate the effect of the high latitude North Atlantic subsurface ocean temperature response in idealized freshwater hosing experiments on the strength of the Atlantic meridional overturning circulation (AMOC). The hosing experiments covered a range of input magnitudes at two locations in a glacial background state. Subsurface subpolar ocean warms when freshwater is added to the high latitude North Atlantic (NATL cases) and weakly cools when freshwater is added to the Gulf of Mexico (GOM cases). All cases show subsurface ocean warming in the Southern Hemisphere (SH). The sensitivity of the AMOC response to the location and magnitude of hosing is related to the induced subsurface temperature response, which affects the magnitude of the large-scale meridional pressure gradient at depth through the effect on upper ocean density. The high latitude subsurface warming induced in the NATL cases lowers the upper ocean density in the deepwater formation region enhancing a density reduction by local freshening. In the GOM cases the effect of SH warming partially offsets the effect of the high latitude freshening on the meridional density gradient. Following the end of hosing, a brief convective event occurs in the largest NATL cases which flushes some of the heat stored in the subsurface layers. This fuels a rapid rise in AMOC that lasts less than a couple of decades before subsequent freshening from increases in precipitation and sea ice melt reverses the initial increase in the meridional density gradient. Thereafter AMOC recovery slows to the rate found in comparable GOM cases. The result for these glacial transient hosing experiments is that the pace of the longer recovery is not sensitive to location of the imposed freshwater forcing. (orig.)

  1. Warm water deuterium fractionation in IRAS 16293-2422

    DEFF Research Database (Denmark)

    Persson, Magnus Vilhelm; Jørgensen, Jes Kristian; van Dishoeck, E. F.

    2013-01-01

    observations reveal the physical and chemical structure of water vapor close to the protostars on solar-system scales. The red-shifted absorption detected toward source B is indicative of infall. The excitation temperature is consistent with the picture of water ice evaporation close to the protostar. The low......Context. Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength...... interferometers have the potential to shed light on this matter. Aims: To measure the water deuterium fractionation in the warm gas of the deeply-embedded protostellar binary IRAS 16293-2422. Methods: Observations toward IRAS 16293-2422 of the 53,2 - 44,1 transition of H218O at 692.07914 GHz from Atacama Large...

  2. On the impact of the resolution on the surface and subsurface Eastern Tropical Atlantic warm bias

    Science.gov (United States)

    Martín-Rey, Marta; Lazar, Alban

    2016-04-01

    The tropical variability has a great importance for the climate of adjacent areas. Its sea surface temperature anomalies (SSTA) affect in particular the Brazilian Nordeste and the Sahelian region, as well as the tropical Pacific or the Euro-Atlantic sector. Nevertheless, the state-of the art climate models exhibits very large systematic errors in reproducing the seasonal cycle and inter-annual variability in the equatorial and coastal Africa upwelling zones (up to several °C for SST). Theses biases exist already, in smaller proportions though, in forced ocean models (several 1/10th of °C), and affect not only the mixed layer but also the whole thermocline. Here, we present an analysis of the impact of horizontal and vertical resolution changes on these biases. Three different DRAKKAR NEMO OGCM simulations have been analysed, associated to the same forcing set (DFS4.4) with different grid resolutions: "REF" for reference (1/4°, 46 vertical levels), "HH" with a finer horizontal grid (1/12°, 46 v.l.) and "HV" with a finer vertical grid (1/4°, 75 v.l.). At the surface, a more realistic seasonal SST cycle is produced in HH in the three upwellings, where the warm bias decreases (by 10% - 20%) during boreal spring and summer. A notable result is that increasing vertical resolution in HV causes a shift (in advance) of the upwelling SST seasonal cycles. In order to better understand these results, we estimate the three upwelling subsurface temperature errors, using various in-situ datasets, and provide thus a three-dimensional view of the biases.

  3. A GCM Study of Responses of the Atmospheric Water Cycle of West Africa and the Atlantic to Saharan Dust Radiative Forcing

    Science.gov (United States)

    Lau, K. M.; Kim, K. M.; Sud, Y. C.; Walker, G. K.

    2009-01-01

    The responses of the atmospheric water cycle and climate of West Africa and the Atlantic to radiative forcing of Saharan dust are studied using the NASA finite volume general circulation model (fvGCM), coupled to a mixed layer ocean. We find evidence of an "elevated heat pump" (EHP) mechanism that underlines the responses of the atmospheric water cycle to dust forcing as follow. During the boreal summerr, as a result of large-scale atmospheric feedback triggered by absorbing dust aerosols, rainfall and cloudiness are ehanIed over the West Africa/Eastern Atlantic ITCZ, and suppressed over the West Atlantic and Caribbean region. Shortwave radiation absorption by dust warms the atmosphere and cools the surface, while longwave has the opposite response. The elevated dust layer warms the air over West Africa and the eastern Atlantic. As the warm air rises, it spawns a large-scale onshore flow carrying the moist air from the eastern Atlantic and the Gulf of Guinea. The onshore flow in turn enhances the deep convection over West Africa land, and the eastern Atlantic. The condensation heating associated with the ensuing deep convection drives and maintains an anomalous large-scale east-west overturning circulation with rising motion over West Africa/eastern Atlantic, and sinking motion over the Caribbean region. The response also includes a strengthening of the West African monsoon, manifested in a northward shift of the West Africa precipitation over land, increased low-level westerlies flow over West Africa at the southern edge of the dust layer, and a near surface westerly jet underneath the dust layer overr the Sahara. The dust radiative forcing also leads to significant changes in surface energy fluxes, resulting in cooling of the West African land and the eastern Atlantic, and warming in the West Atlantic and Caribbean. The EHP effect is most effective for moderate to highly absorbing dusts, and becomes minimized for reflecting dust with single scattering albedo at0

  4. Variability along the Atlantic water pathway in the forced Norwegian Earth System Model

    Science.gov (United States)

    Langehaug, H. R.; Sandø, A. B.; Årthun, M.; Ilıcak, M.

    2018-03-01

    The growing attention on mechanisms that can provide predictability on interannual-to-decadal time scales, makes it necessary to identify how well climate models represent such mechanisms. In this study we use a high (0.25° horizontal grid) and a medium (1°) resolution version of a forced global ocean-sea ice model, utilising the Norwegian Earth System Model, to assess the impact of increased ocean resolution. Our target is the simulation of temperature and salinity anomalies along the pathway of warm Atlantic water in the subpolar North Atlantic and the Nordic Seas. Although the high resolution version has larger biases in general at the ocean surface, the poleward propagation of thermohaline anomalies is better resolved in this version, i.e., the time for an anomaly to travel northward is more similar to observation based estimates. The extent of these anomalies can be rather large in both model versions, as also seen in observations, e.g., stretching from Scotland to northern Norway. The easternmost branch into the Nordic and Barents Seas, carrying warm Atlantic water, is also improved by higher resolution, both in terms of mean heat transport and variability in thermohaline properties. A more detailed assessment of the link between the North Atlantic Ocean circulation and the thermohaline anomalies at the entrance of the Nordic Seas reveals that the high resolution is more consistent with mechanisms that are previously published. This suggests better dynamics and variability in the subpolar region and the Nordic Seas in the high resolution compared to the medium resolution. This is most likely due a better representation of the mean circulation in the studied region when using higher resolution. As the poleward propagation of ocean heat anomalies is considered to be a key source of climate predictability, we recommend that similar methodology presented herein should be performed on coupled climate models that are used for climate prediction.

  5. Are the Chesapeake Bay waters warming up

    International Nuclear Information System (INIS)

    Brady, D.K.

    1976-01-01

    Apparently significant trends within moderately long (50-year) series of meteorological or hydrological data should be regarded with suspicion until justified on the basis of much longer term information. Extra efforts should be directed toward securing the continuance of routine observations at stations where long data histories are already available and where the termination of such records might be regretted at some future time. Mean annual air and water temperatures at different sites may be quite highly correlated even when the points of measurement are very widely separated. The annual average water temperature at one station close to the Chesapeake Bay appears to be normally distributed with a standard deviation of 0.7 0 C about a stationary overall mean value of 14.6 0 C. Its 1000-year departure is +- 2.2 0 C

  6. Dispersion in North Atlantic Deep Water transfer between the northern source region and the South Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Huhn, Oliver; Roether, Wolfgang [Institut fuer Umweltphysik, Universitaet Bremen (Germany)

    2007-07-01

    North Atlantic Deep Water (NADW) represents the Atlantic part of the deep, southward return arm of the oceanic 'conveyor belt', which moderates Europe's climate and effects most of the water transfer from the ocean surface into the deep waters globally. The transfer starts from the NADW formation regions, which in the case of upper NADW (approx. 1500-2000 m depth) is the Labrador Sea (far NW Atlantic). NADW is found concentrated toward the continental slope of the Americas, but subject to meandering, and to recirculation into, and mixing with, the waters of the interior Atlantic. Individual water parcels thus follow a complex ensemble of trajectories. We have obtained characteristics of that ensemble by fitting the free parameters of a suitable function using extensive observations of the transient tracers CFC-11, CFC-12, CCl{sub 4}, and tritium. A tracer transfer function of ocean-surface concentrations to those in newly formed NADW was derived as a precursory step. In the upper NADW we obtain RMS transfer-time dispersions on the way from the Labrador Sea of 31 years at 6 N rising to 53 years at 20 S, compared to mean transfer times ranging 46 to 79 years ({+-}20 %); furthermore, approximately 10 % to 40 % of the water is old, tracer-free water admixed on the way. Similar results have been obtained for lower NADW (approx. 2500-4000 m). The combination of tritium and CFC observations is particularly suited to constrain the dispersion, since it acts on the concentrations of these tracers in an opposite way. The tracer-adjusted transfer functions allow quantification of the NADW transport of pollutants and other compounds delivered to the NADW formation region. The results can furthermore check mean transfer times and large-scale dispersion of the NADW part of dynamic ocean circulation models.

  7. Observations of Warm Water in Young Solar-System Analogs

    DEFF Research Database (Denmark)

    Persson, Magnus Vilhelm

    dioxide). The amount of warm water is deduced and its origin is observationally constrained. With both isotopologues observed, the HDO/H2O ratio is deduced. This ratio is then compared to other sources, e.g., comets and the Earth’s ocean, to gain understanding of the origin of the water in our own solar...... system. The emission line fluxes are modeled with radiative transfer tools and compared to other results of water abundances in the same source. The observed water emission, both H18(2 O and HDO is compact for all observed sources and traces the emission on R 150 AU scales or less. In one source...

  8. Northward advection of Atlantic water in the eastern Nordic Seas over the last 3000 yr

    Directory of Open Access Journals (Sweden)

    C. V. Dylmer

    2013-07-01

    Full Text Available Three marine sediment cores distributed along the Norwegian (MD95-2011, Barents Sea (JM09-KA11-GC, and Svalbard (HH11-134-BC continental margins have been investigated in order to reconstruct changes in the poleward flow of Atlantic waters (AW and in the nature of upper surface water masses within the eastern Nordic Seas over the last 3000 yr. These reconstructions are based on a limited set of coccolith proxies: the abundance ratio between Emiliania huxleyi and Coccolithus pelagicus, an index of Atlantic vs. Polar/Arctic surface water masses; and Gephyrocapsa muellerae, a drifted coccolith species from the temperate North Atlantic, whose abundance changes are related to variations in the strength of the North Atlantic Current. The entire investigated area, from 66 to 77° N, was affected by an overall increase in AW flow from 3000 cal yr BP (before present to the present. The long-term modulation of westerlies' strength and location, which are essentially driven by the dominant mode of the North Atlantic Oscillation (NAO, is thought to explain the observed dynamics of poleward AW flow. The same mechanism also reconciles the recorded opposite zonal shifts in the location of the Arctic front between the area off western Norway and the western Barents Sea–eastern Fram Strait region. The Little Ice Age (LIA was governed by deteriorating conditions, with Arctic/Polar waters dominating in the surface off western Svalbard and western Barents Sea, possibly associated with both severe sea ice conditions and a strongly reduced AW strength. A sudden short pulse of resumed high WSC (West Spitsbergen Current flow interrupted this cold spell in eastern Fram Strait from 330 to 410 cal yr BP. Our dataset not only confirms the high amplitude warming of surface waters at the turn of the 19th century off western Svalbard, it also shows that such a warming was primarily induced by an excess flow of AW which stands as unprecedented over the last 3000 yr.

  9. SPREADING OF ANTARCTIC BOTTOM WATER IN THE ATLANTIC OCEAN

    Directory of Open Access Journals (Sweden)

    Eugene Morozov

    2012-01-01

    Full Text Available This paper describes the transport of bottom water from its source region in the Weddell Sea through the abyssal channels of the Atlantic Ocean. The research brings together the recent observations and historical data. A strong flow of Antarctic Bottom Water through the Vema Channel is analyzed. The mean speed of the flow is 30 cm/s. A temperature increase was found in the deep Vema Channel, which has been observed for 30 years already. The flow of bottom water in the northern part of the Brazil Basin splits. Part of the water flows through the Romanche and Chain fracture zones. The other part flows to the North American Basin. Part of the latter flow propagates through the Vema Fracture Zone into the Northeast Atlantic. The properties of bottom water in the Kane Gap and Discovery Gap are also analyzed.

  10. Dissolved Carbon Dioxide in Tropical East Atlantic Surface Waters

    NARCIS (Netherlands)

    Bakker, D.C.E.; Baar, H.J.W. de; Jong, E. de

    1999-01-01

    Variability of dissolved inorganic carbon (DIC) and the fugacity of carbon dioxide (fCO2) is discussed for tropical East Atlantic surface waters in October–November 1993 and May–June 1994. High precipitation associated with the Intertropical Convergence Zone, river input and equatorial upwelling

  11. Application of solar radiation for heating and preparation of warm water in an individual house

    International Nuclear Information System (INIS)

    Kozak, Tadeeusz; Majchrzycka, Anna

    2009-01-01

    The paper is aimed at analysis of application of the solar collectors array for preparing of warm water and space heating in an individual house. Keywords: application of solar radiation, preparation of warm water, heating

  12. Atlantic water variability on the SE Greenland continental shelf and its relationship to SST

    Science.gov (United States)

    Sutherland, D. A.; Straneo, F.; Rosing-Asvid, A.; Stenson, G.; Davidson, F. J.; Hammill, M.

    2012-12-01

    Interaction of warm, Atlantic-origin water (AW) and colder, polar origin water (PW) advecting southward in the East Greenland Current (EGC) influences the heat content of water entering Greenland's outlet glacial fjords. Here we use depth and temperature data derived from deep-diving seals to map out water mass variability across the continental shelf and to augment existing bathymetric products. We find two dominant modes in the vertical temperature structure: a cold mode, with the typical AW/PW layering observed in the EGC, and a warm mode, where AW is present throughout the water column. The prevalence of these modes varies seasonally and spatially across the continental shelf, implying distinct AW pathways. In addition, we find that satellite sea surface temperatures (SST) correlate significantly with temperatures in the upper 50 m (R=0.54), but this correlation decreases with depth (R=0.22 at 200 m), and becomes insignificant below 250 m. Thus, care must be taken in using SST as a proxy for heat content, as AW mainly resides in these deeper layers. Regional map showing the location of all seal tracks originating from Canada and Greenland (stars). Tracks passing inside (red) or outside (blue) the SE Greenland region (black) were subdivided into continental shelf regions (green boxes) near Sermilik Fjord (SF), Cape Farewell (CF) and Kangerdlugssuaq Fjord (KG). GEBCO bathymetry is contoured at 200, 1000, 2000, and 3000 m.

  13. Southern limit of the Western South Atlantic mangroves: Assessment of the potential effects of global warming from a biogeographical perspective

    Science.gov (United States)

    Soares, Mário Luiz Gomes; Estrada, Gustavo Calderucio Duque; Fernandez, Viviane; Tognella, Mônica Maria Pereira

    2012-04-01

    The objective of the present study was to determine the exact location of the latitudinal limit of western South Atlantic mangroves, and to describe how these forests develop at this limit; as well as to analyze the potential responses of these communities to global warming. The study was carried out along the coast of Santa Catarina, Brazil. Specific studies on mangrove structure were carried out in the Santo Antônio Lagoon (28°28'34″S; 48°51'40″W). The coastline of Santa Catarina was surveyed for the occurrence of mangrove species. In the mangrove located at the southernmost distributional limit, the forest structure was characterized. Mean height and diameter, trunks density and basal area were calculated. Climatic and oceanographic factors controlling the occurrence and development of the mangrove forests at their latitudinal limit were analyzed, as well as the possible changes of this limit based on global warming scenarios. The results confirmed that the Santo Antônio Lagoon is the southern limit of the western South Atlantic mangroves. At this limit, the mangrove forests show a low degree of development, defined by low mean diameter and height, and high trunks density and trunks/tree ratio. The observed structural pattern and the local alternation of these forests with salt marsh species are typical of mangrove forests at their latitudinal limits. The absence of mangroves south of Laguna and forest structure at the latitudinal limit are controlled by rigorous climate and oceanographic characteristics. In response to the planetary warming process, we expect that mangroves will expand southward, as a consequence of an increase in air and ocean surface temperatures, a reduction in the incidence of frosts, an increased influence of the Brazil Current and a decreased influence of the Falkland Current, and the availability of sheltered estuarine systems for the establishment of new mangroves.

  14. Deterioration of atlantic soft water macrophyte communities by acidification, eutrophication and alkalinisation

    NARCIS (Netherlands)

    Arts, G.H.P.

    2002-01-01

    This review presents an overview of the most important succession patterns and underlying processes associated with the deterioration of soft water macrophyte communities in atlantic and boreo-atlantic regions. As acidification, eutrophication and alkalinisation are the dominant processes, this

  15. North Atlantic deep water formation and AMOC in CMIP5 models

    Directory of Open Access Journals (Sweden)

    C. Heuzé

    2017-07-01

    Full Text Available Deep water formation in climate models is indicative of their ability to simulate future ocean circulation, carbon and heat uptake, and sea level rise. Present-day temperature, salinity, sea ice concentration and ocean transport in the North Atlantic subpolar gyre and Nordic Seas from 23 CMIP5 (Climate Model Intercomparison Project, phase 5 models are compared with observations to assess the biases, causes and consequences of North Atlantic deep convection in models. The majority of models convect too deep, over too large an area, too often and too far south. Deep convection occurs at the sea ice edge and is most realistic in models with accurate sea ice extent, mostly those using the CICE model. Half of the models convect in response to local cooling or salinification of the surface waters; only a third have a dynamic relationship between freshwater coming from the Arctic and deep convection. The models with the most intense deep convection have the warmest deep waters, due to a redistribution of heat through the water column. For the majority of models, the variability of the Atlantic Meridional Overturning Circulation (AMOC is explained by the volumes of deep water produced in the subpolar gyre and Nordic Seas up to 2 years before. In turn, models with the strongest AMOC have the largest heat export to the Arctic. Understanding the dynamical drivers of deep convection and AMOC in models is hence key to realistically forecasting Arctic oceanic warming and its consequences for the global ocean circulation, cryosphere and marine life.

  16. Spreading of Antarctic Bottom Water in the Atlantic Ocean

    OpenAIRE

    Morozov, E.; Tarakanov, R. Y.; Zenk, Walter

    2012-01-01

    This paper describes the transport of bottom water from its source region in the Weddell Sea through the abyssal channels of the Atlantic Ocean. The research brings together the recent observations and historical data. A strong flow of Antarctic Bottom Water through the Vema Channel is analyzed. The mean speed of the flow is 30 cm/s. A temperature increase was found in the deep Vema Channel, which has been observed for 30 years already. The flow of bottom water in the northern part of the Bra...

  17. CAGE BREEDING OF WARM WATER FRESHWATER FISH SPECIES

    Directory of Open Access Journals (Sweden)

    Roman Safner

    2008-10-01

    Full Text Available In the 1970s, Croatia became actively involved in the contemporary trend of breeding fish in floating cages. In addition to various species of marine fishes, breeding was attempted with trout, carp, catfish, cisco and salmon. Of the above freshwater fish species, specific standards were established only for the cage breeding of rainbow trout. Cage breeding of the remaining species remained at the level of occasional attempts, with more of an experimental than a commercial character. The regular attempts to master this technique for cage breeding of warm water freshwater fish species were aimed at achieving the known benefits of such breeding, such as simplicity of implementing technological measures, easier establishment of the breeding system, simpler manipulation, the possibility of denser colonies per unit volume with a high level of production, easier adaptations to market conditions and fewer initial structural investments. Despite the many advantages, the main reasons for the lack of greater implementation of the cage breeding technology for warm water species of freshwater fish include problems in obtaining the appropriate category and quantity of healthy fry, the specificity and applicability of physical and chemical properties of the recipients and human error. In evaluating the advantages and disadvantages, the final decision on the justification of cage breeding for individual warm water freshwater species must be based on both biological and economic factors. Based on the knowledge of cage breeding acquired to date, the rule for virtually all intensive breeding systems is that it is only recommended for those species with high market demand and a high market price. The technology that demands nutrition with highly concentrated feed and other production expenditures is costly, and is therefore not profitable with less expensive fish species. Furthermore, production must be market oriented, i.e. the appropriate market research measures

  18. Electrolytically generated hydrogen warm water cleanses the keratin-plug-clogged hair-pores and promotes the capillary blood-streams, more markedly than normal warm water does

    Directory of Open Access Journals (Sweden)

    Yoshiharu Tanaka

    2018-01-01

    Full Text Available Biomedical properties of hydrogen water have been extensively investigated, but the effect of hydrogen on good healthy subjects remains unclear. This study was designed to explore the hygiene improvement by electrolytically generated hydrogen warm water (40°C on capillary blood streams, skin moisture, and keratin plugs in skin pores in normal good healthy subjects with their informed consents. Fingertip-capillary blood stream was estimated after hand-immersing in hydrogen warm water by videography using a CCD-based microscope, and the blood flow levels increased to about 120% versus normal warm water, after 60 minutes of the hand-immersing termination. Skin moisture of subjects was assessed using an electro-conductivity-based skin moisture meter. Immediately after taking a bath filled with hydrogen warm water, the skin moisture increased by 5–10% as compared to before bathing, which was kept on for the 7-day test, but indistinct, because of lower solubility of hydrogen in “warm” water than in room-temperature water. Cleansing of keratin plugs in skin-pores was assessed by stereoscopic microscopy and scanning electron microscopy. After hydrogen warm water bathing, the numbers of cleansed keratin plugs also increased on cheek of subjects 2.30- to 4.47-fold as many as the control for normal warm water. And areas of cleansed keratin plugs in the cheeks increased about 1.3-fold as much as the control. More marked improvements were observed on cheeks than on nostrils. Hydrogen warm water may thoroughly cleanse even keratin-plugs of residual amounts that could not be cleansed by normal warm water, through its permeability into wide-ranged portions of hair-pores, and promote the fingertip blood streams more markedly than merely through warmness due to normal warm water.

  19. The Mediterranean Water content in the Northeast Atlantic

    Science.gov (United States)

    Nascimento, Angela; Bashmachnikov, Igor; Neves, Filipe

    2014-05-01

    Distribution of the Mediterranean Water (MW) in the subtropical Northeast Atlantic [20-50o N, 5-40o W] was studied using Optimum Multiparameter analysis (OMP) applied to the World Ocean Atlas (http://www.nodc.noaa.gov/) and MEDTRANS climatologies (http://co.fc.ul.pt/en/). The areas of influence of water masses in the study region were obtained from literature and from analysis of individual TS-diagrams. The analysis permitted to divide the water column between 500 to 2000 m into 5 vertical layers. The boundaries of the layers separated different expected sets of the dominant water masses; their depth varied across the study region. For the OMP we used the following water masses: the central fraction of the North Atlantic Central Water (H), the lower fraction of the North Atlantic Central Water (NACWl), the Mediterranean Water (MW), the Sub-Artic Intermediate Water (SAIW), the modified Antarctic Intermediate Water (AA), the Labrador Sea Water (LSW) and the upper fraction of the North Atlantic Deep Water (NADWu). The characteristics of the water masses were obtained from Perez et al. (2001), Alvarez et al. (2004) and Barbero et al. (2010), taken at the places where the water masses entered the study region. For each of the layers and each of the grid-points OMP was applied for estimation of the percentage of the each of the water masses in the observed mixture. The analysis of sensitivity of the results to the definition of water mass proprieties showed that their percentages were derived within the average error of 10%. The percentages of water masses obtained in this study compared well with the previous OMP results at some individual sections across our region (Hinrichsen and Tomczak, 1993; Alvarez et al., 2004 and Barbero et al., 2010). In this work we specifically focused on distribution of the MW. The results showed that the MW reached its maximum of 50% at 1200 m depth in the Gulf of Cadiz. The percentage decreased to about 40% along the Iberian continental

  20. Chemical and Hydro-Geologic Analysis of Ikogosi Warm Spring Water in Nigeria

    OpenAIRE

    Akinola Ikudayisi; Folasade Adeyemo; Josiah Adeyemo

    2015-01-01

    This study focuses on the hydro-geology and chemical constituents analysis of Ikogosi Warm Spring waters in South West Nigeria. Ikogosi warm spring is a global tourist attraction because it has both warm and cold spring sources. Water samples from the cold spring, warm spring and the meeting point were collected, analyzed and the result shows close similarity in temperature, hydrogen iron concentration (pH), alkalinity, hardness, Calcium, Magnesium, Sodium, Iron, total di...

  1. The Effect of Seasonal Variability of Atlantic Water on the Arctic Sea Ice Cover

    Science.gov (United States)

    Ivanov, V. V.; Repina, I. A.

    2018-01-01

    Under the influence of global warming, the sea ice in the Arctic Ocean (AO) is expected to reduce with a transition toward a seasonal ice cover by the end of this century. A comparison of climate-model predictions with measurements shows that the actual rate of ice cover decay in the AO is higher than the predicted one. This paper argues that the rapid shrinking of the Arctic summer ice cover is due to its increased seasonality, while seasonal oscillations of the Atlantic origin water temperature create favorable conditions for the formation of negative anomalies in the ice-cover area in winter. The basis for this hypothesis is the fundamental possibility of the activation of positive feedback provided by a specific feature of the seasonal cycle of the inflowing Atlantic origin water and the peaking of temperature in the Nansen Basin in midwinter. The recently accelerated reduction in the summer ice cover in the AO leads to an increased accumulation of heat in the upper ocean layer during the summer season. The extra heat content of the upper ocean layer favors prerequisite conditions for winter thermohaline convection and the transfer of heat from the Atlantic water (AW) layer to the ice cover. This, in turn, contributes to further ice thinning and a decrease in ice concentration, accelerated melting in summer, and a greater accumulation of heat in the ocean by the end of the following summer. An important role is played by the seasonal variability of the temperature of AW, which forms on the border between the North European and Arctic basins. The phase of seasonal oscillation changes while the AW is moving through the Nansen Basin. As a result, the timing of temperature peak shifts from summer to winter, additionally contributing to enhanced ice melting in winter. The formulated theoretical concept is substantiated by a simplified mathematical model and comparison with observations.

  2. Discharge, water temperature, and water quality of Warm Mineral Springs, Sarasota County, Florida: A retrospective analysis

    Science.gov (United States)

    Metz, Patricia A.

    2016-09-27

    Warm Mineral Springs, located in southern Sarasota County, Florida, is a warm, highly mineralized, inland spring. Since 1946, a bathing spa has been in operation at the spring, attracting vacationers and health enthusiasts. During the winter months, the warm water attracts manatees to the adjoining spring run and provides vital habitat for these mammals. Well-preserved late Pleistocene to early Holocene-age human and animal bones, artifacts, and plant remains have been found in and around the spring, and indicate the surrounding sinkhole formed more than 12,000 years ago. The spring is a multiuse resource of hydrologic importance, ecological and archeological significance, and economic value to the community.The pool of Warm Mineral Springs has a circular shape that reflects its origin as a sinkhole. The pool measures about 240 feet in diameter at the surface and has a maximum depth of about 205 feet. The sinkhole developed in the sand, clay, and dolostone of the Arcadia Formation of the Miocene-age to Oligocene-age Hawthorn Group. Underlying the Hawthorn Group are Oligocene-age to Eocene-age limestones and dolostones, including the Suwannee Limestone, Ocala Limestone, and Avon Park Formation. Mineralized groundwater, under artesian pressure in the underlying aquifers, fills the remnant sink, and the overflow discharges into Warm Mineral Springs Creek, to Salt Creek, and subsequently into the Myakka River. Aquifers described in the vicinity of Warm Mineral Springs include the surficial aquifer system, the intermediate aquifer system within the Hawthorn Group, and the Upper Floridan aquifer in the Suwannee Limestone, Ocala Limestone, and Avon Park Formation. The Hawthorn Group acts as an upper confining unit of the Upper Floridan aquifer.Groundwater flow paths are inferred from the configuration of the potentiometric surface of the Upper Floridan aquifer for September 2010. Groundwater flow models indicate the downward flow of water into the Upper Floridan aquifer

  3. Gateways and Water Mass Mixing in the Late Cretaceous North Atlantic

    Science.gov (United States)

    Asgharian Rostami, M.; Martin, E. E.; MacLeod, K. G.; Poulsen, C. J.; Vande Guchte, A.; Haynes, S.

    2017-12-01

    Regions of intermediate/deep water formation and water-mass mixing in the North Atlantic are poorly defined for the Late Cretaceous, a time of gateway evolution and cooler conditions following the Mid Cretaceous greenhouse. Improved proxy data combined with modeling efforts are required to effectively evaluate the relationship between CO2, paleogeography, and circulation during this cooler interval. We analyzed and compiled latest Cretaceous (79 - 66 Ma) ɛNd and δ13C records from seven bathyal (paleodepths 0.2 - 2 km) and eight abyssal (paleodepths > 2 km) sites in the North Atlantic. Data suggest local downwelling of Northern Component Water (NCW; ɛNd -9.5 and δ13C 1.7 ‰) is the primary source of intermediate/deep water masses in the basin. As this water flows southward and ages, δ13C values decrease and ɛNd values increase; however, additional chemical changes at several sites require mixing with contributions from several additional water masses. Lower ɛNd ( -10) and higher δ13C ( 1.9 ‰) values in the deep NW part of the basin indicate proximal contributions from a region draining old continental crust, potentially representing deep convection following opening of the Labrador Sea. In the deep NE Iberian Basin, higher ɛNd ( -7) and lower δ13C ( 0.8 ‰) during the Campanian suggest mixing with a Tethyan source (ɛNd -7 and δ13C 0.1 ‰) whose importance decreased with restriction of that gateway in the Maastrichtian. Data from bathyal sites suggest additional mixing. In the SE Cape Verde region, observed ɛNd variations from -10 in the Campanian to -13 and -12 in the early and late Maastrichtian, respectively, may record variations in output rates of Tethyan and/or NCW sources and Demerara Bottom Water (ɛNd -16), a proposed warm saline intermediate water mass formed in shallow, equatorial seas. Pacific inflow through the Caribbean gateway impacts intermediate sites at Blake Nose (ɛNd values -8), particularly the shallowest site during the late

  4. Atlantic water heat transfer through the Arctic Gateway (Fram Strait) during the Last Interglacial

    Science.gov (United States)

    Zhuravleva, Anastasia; Bauch, Henning A.; Spielhagen, Robert F.

    2017-10-01

    The Last Interglacial in the Arctic region is often described as a time with warmer conditions and significantly less summer sea ice than today. The role of Atlantic water (AW) as the main oceanic heat flux agent into the Arctic Ocean remains, however, unclear. Using high-resolution stable isotope and faunal records from the only deep Arctic Gateway, the Fram Strait, we note for the upper water column a diminished influence of AW and generally colder-than-Holocene surface ocean conditions. After the main Saalian deglaciation had terminated, a first intensification of northward-advected AW happened ( 124 ka). However, an intermittent sea surface cooling, triggered by meltwater release at 122 ka, caused a regional delay in the further development towards peak interglacial conditions. Maximum AW heat advection occurred during late MIS 5e (118.5-116 ka) and interrupted a longer-term cooling trend at the sea surface that started from about 120 ka on. Such a late occurrence of the major AW-derived near-surface warming in the Fram Strait - this is in stark contrast to an early warm peak in the Holocene - compares well in time with upstream records from the Norwegian Sea, altogether implying a coherent development of south-to-north ocean heat transfer through the eastern Nordic Seas and into the high Arctic during the Last Interglacial.

  5. Warm water and cool nests are best. How global warming might influence hatchling green turtle swimming performance.

    Directory of Open Access Journals (Sweden)

    David T Booth

    Full Text Available For sea turtles nesting on beaches surrounded by coral reefs, the most important element of hatchling recruitment is escaping predation by fish as they swim across the fringing reef, and as a consequence hatchlings that minimize their exposure to fish predation by minimizing the time spent crossing the fringing reef have a greater chance of surviving the reef crossing. One way to decrease the time required to cross the fringing reef is to maximize swimming speed. We found that both water temperature and nest temperature influence swimming performance of hatchling green turtles, but in opposite directions. Warm water increases swimming ability, with hatchling turtles swimming in warm water having a faster stroke rate, while an increase in nest temperature decreases swimming ability with hatchlings from warm nests producing less thrust per stroke.

  6. Warm Water Oxidation Verification - Scoping and Stirred Reactor Tests

    Energy Technology Data Exchange (ETDEWEB)

    Braley, Jenifer C.; Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2011-06-15

    Scoping tests to evaluate the effects of agitation and pH adjustment on simulant sludge agglomeration and uranium metal oxidation at {approx}95 C were performed under Test Instructions(a,b) and as per sections 5.1 and 5.2 of this Test Plan prepared by AREVA. (c) The thermal testing occurred during the week of October 4-9, 2010. The results are reported here. For this testing, two uranium-containing simulant sludge types were evaluated: (1) a full uranium-containing K West (KW) container sludge simulant consisting of nine predominant sludge components; (2) a 50:50 uranium-mole basis mixture of uraninite [U(IV)] and metaschoepite [U(VI)]. This scoping study was conducted in support of the Sludge Treatment Project (STP) Phase 2 technology evaluation for the treatment and packaging of K-Basin sludge. The STP is managed by CH2M Hill Plateau Remediation Company (CHPRC) for the U.S. Department of Energy. Warm water ({approx}95 C) oxidation of sludge, followed by immobilization, has been proposed by AREVA and is one of the alternative flowsheets being considered to convert uranium metal to UO{sub 2} and eliminate H{sub 2} generation during final sludge disposition. Preliminary assessments of warm water oxidation have been conducted, and several issues have been identified that can best be evaluated through laboratory testing. The scoping evaluation documented here was specifically focused on the issue of the potential formation of high strength sludge agglomerates at the proposed 95 C process operating temperature. Prior hydrothermal tests conducted at 185 C produced significant physiochemical changes to genuine sludge, including the formation of monolithic concretions/agglomerates that exhibited shear strengths in excess of 100 kPa (Delegard et al. 2007).

  7. Warm Water Oxidation Verification - Scoping and Stirred Reactor Tests

    International Nuclear Information System (INIS)

    Braley, Jenifer C.; Sinkov, Sergey I.; Delegard, Calvin H.; Schmidt, Andrew J.

    2011-01-01

    Scoping tests to evaluate the effects of agitation and pH adjustment on simulant sludge agglomeration and uranium metal oxidation at ∼95 C were performed under Test Instructions(a,b) and as per sections 5.1 and 5.2 of this Test Plan prepared by AREVA. (c) The thermal testing occurred during the week of October 4-9, 2010. The results are reported here. For this testing, two uranium-containing simulant sludge types were evaluated: (1) a full uranium-containing K West (KW) container sludge simulant consisting of nine predominant sludge components; (2) a 50:50 uranium-mole basis mixture of uraninite (U(IV)) and metaschoepite (U(VI)). This scoping study was conducted in support of the Sludge Treatment Project (STP) Phase 2 technology evaluation for the treatment and packaging of K-Basin sludge. The STP is managed by CH2M Hill Plateau Remediation Company (CHPRC) for the U.S. Department of Energy. Warm water (∼95 C) oxidation of sludge, followed by immobilization, has been proposed by AREVA and is one of the alternative flowsheets being considered to convert uranium metal to UO 2 and eliminate H 2 generation during final sludge disposition. Preliminary assessments of warm water oxidation have been conducted, and several issues have been identified that can best be evaluated through laboratory testing. The scoping evaluation documented here was specifically focused on the issue of the potential formation of high strength sludge agglomerates at the proposed 95 C process operating temperature. Prior hydrothermal tests conducted at 185 C produced significant physiochemical changes to genuine sludge, including the formation of monolithic concretions/agglomerates that exhibited shear strengths in excess of 100 kPa (Delegard et al. 2007).

  8. Increased ventilation of Antarctic deep water during the warm mid-Pliocene.

    Science.gov (United States)

    Zhang, Zhongshi; Nisancioglu, Kerim H; Ninnemann, Ulysses S

    2013-01-01

    The mid-Pliocene warm period is a recent warm geological period that shares similarities with predictions of future climate. It is generally held the mid-Pliocene Atlantic Meridional Overturning Circulation must have been stronger, to explain a weak Atlantic meridional δ(13)C gradient and large northern high-latitude warming. However, climate models do not simulate such stronger Atlantic Meridional Overturning Circulation, when forced with mid-Pliocene boundary conditions. Proxy reconstructions allow for an alternative scenario that the weak δ(13)C gradient can be explained by increased ventilation and reduced stratification in the Southern Ocean. Here this alternative scenario is supported by simulations with the Norwegian Earth System Model (NorESM-L), which simulate an intensified and slightly poleward shifted wind field off Antarctica, giving enhanced ventilation and reduced stratification in the Southern Ocean. Our findings challenge the prevailing theory and show how increased Southern Ocean ventilation can reconcile existing model-data discrepancies about Atlantic Meridional Overturning Circulation while explaining fundamental ocean features.

  9. Uranium-thorium disequilibrium in north-east Atlantic waters

    International Nuclear Information System (INIS)

    Smith, K.J.; Leon Vintro, L.; Mitchell, P.I.; Bally de Bois, P.; Boust, D.

    2004-01-01

    In this paper we report and compare the concentrations of 234 Th and 238 U measured in surface and subsurface waters collected in the course of a sampling campaign in the north east Atlantic in June-July 1998. Dissolved 234 Th concentrations in surface waters ranged from 5 to 20 Bq m -3 , showing a large deficiency relative to 238 U concentrations (typically 42 Bq m -3 ). This disequilibrium is indicative of active 234 Th scavenging from surface waters. Observed 234 Th/ 238 U activity ratios, together with corresponding 234 Th particulate concentrations, were used to calculate mean residence times for 234 Th with respect to scavenging onto particles (τ diss ) and subsequent removal from surface waters (τ part ). Residence times in the range 5-30 days were determined for τ diss and 4-18 days for τ part (n=14). In addition, ultrafiltration experiments at six stations in the course of the same expedition revealed that in north-east Atlantic surface waters a significant fraction (46±17%; n=6) of the thorium in the (operationally-defined) dissolved phase ( 234 Th is rapidly absorbed by colloidal particles, which then aggregate, albeit at a slower rate, into larger filterable particles. In essence, colloids act as intermediaries in the transition from the fully dissolved to the filter-retained (>0.45 μm) phase. Thus, the time (τ c ) for fully dissolved 234 Th to appear in the filter-retained fraction is dependent on the rate of colloidal aggregation. Here, we determined τ c values in the range 3-17 days

  10. Deep-water fisheries at the Atlantic Frontier

    Science.gov (United States)

    Gordon, J. D. M.

    2001-05-01

    The deep sea is often thought of as a cold, dark and uniform environment with a low-fish biomass, much of which is highly adapted for life in a food-poor environment. While this might be true of the pelagic fish living in the water column, it is certainly not true of the demersal fish which live on or close to the bottom on the continental slopes around the British Isles (the Atlantic Frontier). These fish are currently being commercially exploited. There is growing evidence to support the view that success of the demersal fish assemblages depends on the pelagic or benthopelagic food sources that impinge both vertically and horizontally onto the slope. There are several quite separate and distinct deep-water fisheries on the Atlantic Frontier. It is a physical barrier, the Wyville-Thomson Ridge, which results in the most significant division of the fisheries. The Ridge, which has a minimum depth of about 500 m, separates the warmer deep Atlantic waters from the much colder Norwegian Sea water and as a result, the deep-water fisheries to the west of the Hebrides and around the offshore banks are quite different from those of the Faroe-Shetland Channel (West of Shetland). The fisheries to the West of the Hebrides can be further divided by the fishing method used into bottom trawl, semipelagic trawl and longline. The bottom-trawl fisheries extend from the shelf-slope break down to about 1700 m and the target species varies with depth. The smallest vessels in the fleet fish on the upper slope, where an important target species is the anglerfish or monkfish ( Lophius spp.). On the mid-slope the main target species are blue ling ( Molva dypterygia) and roundnose grenadier ( Coryphaenoides rupestris), with bycatches of black scabbardfish ( Aphanopus carbo) and deep-water sharks. On the lower slope orange roughy ( Hoplostethus atlanticus) is an important target species. The major semipelagic trawl fishery is a seasonal fishery on spawning aggregations of blue whiting

  11. Hydrology and water budget for a forested atlantic coastal plain watershed, South Carolina

    Science.gov (United States)

    Scott V. Harder; Devendra M Amatya; Callahan Timothy J.; Carl C. Trettin; Hakkila Jon

    2007-01-01

    Increases in timber demand and urban development in the Atlantic Coastal Plain over the past decade have motivated studies on the hydrology, water quality, and sustainable management of coastal plain watersheds. However, studies on baseline water budgets are limited for the low-lying, forested watersheds of the Atlantic Coastal Plain. The purpose of this study was to...

  12. Hyrdology and water budget for a forested atlantic coastal plain watershed, South Carolina

    Science.gov (United States)

    Scott V. Harder; Devendra M. Amatya; Timothy J. Callahan; Carl C. Trettin; Jon Hakkila

    2007-01-01

    Increases in timber demand and urban development in the Atlantic Coastal Plain over the past decade have motivated studies on the hydrology, water quality, and sustainable management of coastal plain watersheds. However, studies on baseline water budgets are limited for the low-lying, forested watersheds of the Atlantic Coastal Plain. The purpose of this study was to...

  13. Nanoscale study on water damage for different warm mix asphalt binders

    Directory of Open Access Journals (Sweden)

    Kefei Liu

    2016-11-01

    Full Text Available In order to analyze the water damage to different warm mix asphalt binders from the micro scale, five kinds of asphalt binders, 70#A base asphalt, sasobit warm mix asphalt, energy champion 120 °C (EC120 warm mix asphalt, aspha-min warm mix asphalt, sulfur-extended asphalt modifier (SEAM warm mix asphalt, under different conditions (dry/wet, original/aging are prepared for laboratory tests. The atomic force microscope (AFM is used to observe the surface properties and measure the adhesion force between the asphalt and the mineral aggregate. The obtained results show that under the dry condition aspha-min warm mix asphalt and SEAM warm mix asphalt show stronger adhesive ability with the mineral aggregate compared with other asphalt binders, but also have relatively large dispersion and fluctuation in the tested results; under the wet condition, aspha-min warm mix asphalt and SEAM warm mix asphalt show stronger water damage resistance ability. The EC120 warm mix asphalt and aspha-min warm mix asphalt are less sensitive to moist, and their corresponding adhesion force is less susceptible to the change of external moisture conditions, leading to a better ability to resist water erosion. The aging process significantly lowers the moisture erosion resistance ability, which further impairs the water damage resistance ability. The base asphalt is more sensitive to moisture and more vulnerable to water damage, no matter whether it is under original or aging conditions. The aging aspha-min warm mix asphalt has the least loss of adhesion force, the smallest dispersion of the tested adhesion force, the strongest water damage resistance ability, no matter it is dry or wet. Keywords: Road engineering, Warm mix asphalt, Moisture damage, Atomic force microscope, Microcosmic

  14. Properties and pathways of Mediterranean water eddies in the Atlantic

    Science.gov (United States)

    Bashmachnikov, I.; Neves, F.; Calheiros, T.; Carton, X.

    2015-09-01

    Data from ship vertical casts (NODC data-set), ARGO profiling floats (Coriolis data-set) and RAFOS-type neutral density floats (WOCE data-set) are used to study characteristics of meddies in the Northeast Atlantic. In total 241 Mediterranean water eddies (meddies) and 236 parts of float trajectories within meddies are selected for detailed analysis. The results suggest that the meddy generation rate at the southern and southwestern Iberian Peninsula (Portimao Canyon, cap St. Vincent, Estremadura Promontory, Gorringe Bank) is 3 times that at the northwestern Iberian Peninsula (Porto-Aveiro Canyons, Cape Finisterre and Galicia Bank). Meddies generated south of Estremadura Promontory (the southern meddies), as compared to those generated north of it (the northern meddies), have smaller radii, smaller vertical extension, higher aspect ratio, higher Rossby number and higher stability (stronger potential vorticity anomaly). These latter properties result from the southern meddies higher relative vorticity and stronger buoyancy frequency anomaly. Away from the generation regions, meddy drift concentrates along four main paths: three quasi-zonal paths (Northern, Central, Southern) and a path following the African coast (Coastal). The quasi-zonal paths are aligned to the isolines of the ambient potential vorticity field. Several cross-path exchanges, identified in this work, are aligned to topographic rises. Northward translation of the northern meddies within the North Atlantic Current to the subpolar gyre is detected. Within the first 600 km from the coast, meddy merger is proved to be a common event. This explains the observed difference in radii between the newly generated meddies and those away from the Iberian margin. The decay of the southern meddies proceeds mainly via the loss of their skirts and does not affect meddy cores until the latest stages. The decay of the northern meddies goes in parallel with the decay of their cores. In average meddy decay is achieved

  15. FORMATION OF ORGANIC MOLECULES AND WATER IN WARM DISK ATMOSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Najita, Joan R. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Adamkovics, Mate; Glassgold, Alfred E. [Astronomy Department, University of California, Berkeley, CA 94720 (United States)

    2011-12-20

    Observations from Spitzer and ground-based infrared spectroscopy reveal significant diversity in the molecular emission from the inner few AU of T Tauri disks. We explore theoretically the possible origin of this diversity by expanding on our earlier thermal-chemical model of disk atmospheres. We consider how variations in grain settling, X-ray irradiation, accretion-related mechanical heating, and the oxygen-to-carbon ratio can affect the thermal and chemical properties of the atmosphere at 0.25-40 AU. We find that these model parameters can account for many properties of the detected molecular emission. The column density of the warm (200-2000 K) molecular atmosphere is sensitive to grain settling and the efficiency of accretion-related heating, which may account, at least in part, for the large range in molecular emission fluxes that have been observed. The dependence of the atmospheric properties on the model parameters may also help to explain trends that have been reported in the literature between molecular emission strength and mid-infrared color, stellar accretion rate, and disk mass. We discuss whether some of the differences between our model results and the observations (e.g., for water) indicate a role for vertical transport and freezeout in the disk midplane. We also discuss how planetesimal formation in the outer disk (beyond the snowline) may imprint a chemical signature on the inner few AU of the disk and speculate on possible observational tracers of this process.

  16. FORMATION OF ORGANIC MOLECULES AND WATER IN WARM DISK ATMOSPHERES

    International Nuclear Information System (INIS)

    Najita, Joan R.; Ádámkovics, Máté; Glassgold, Alfred E.

    2011-01-01

    Observations from Spitzer and ground-based infrared spectroscopy reveal significant diversity in the molecular emission from the inner few AU of T Tauri disks. We explore theoretically the possible origin of this diversity by expanding on our earlier thermal-chemical model of disk atmospheres. We consider how variations in grain settling, X-ray irradiation, accretion-related mechanical heating, and the oxygen-to-carbon ratio can affect the thermal and chemical properties of the atmosphere at 0.25-40 AU. We find that these model parameters can account for many properties of the detected molecular emission. The column density of the warm (200-2000 K) molecular atmosphere is sensitive to grain settling and the efficiency of accretion-related heating, which may account, at least in part, for the large range in molecular emission fluxes that have been observed. The dependence of the atmospheric properties on the model parameters may also help to explain trends that have been reported in the literature between molecular emission strength and mid-infrared color, stellar accretion rate, and disk mass. We discuss whether some of the differences between our model results and the observations (e.g., for water) indicate a role for vertical transport and freezeout in the disk midplane. We also discuss how planetesimal formation in the outer disk (beyond the snowline) may imprint a chemical signature on the inner few AU of the disk and speculate on possible observational tracers of this process.

  17. Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water.

    Science.gov (United States)

    Frank, Alexander H; Garcia, Juan A L; Herndl, Gerhard J; Reinthaler, Thomas

    2016-06-01

    To decipher the influence of depth stratification and surface provincialism on the dark ocean prokaryotic community composition, we sampled the major deep-water masses in the eastern North Atlantic covering three biogeographic provinces. Their diversity was evaluated using ordination and canonical analysis of 454 pyrotag sequences. Variance partitioning suggested that 16% of the variation in the bacterial community composition was based on depth stratification while 9% of the variation was due to geographic location. General linear mixed effect models showed that the community of the subsurface waters was connected to the dark ocean prokaryotic communities in different biogeographic provinces. Cluster analysis indicated that some prokaryotic taxa are specific to distinct regions in bathypelagic water masses. Taken together, our data suggest that the dark ocean prokaryotic community composition of the eastern North Atlantic is primed by the formation and the horizontal transport of water masses. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. 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.

  19. 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.

  20. Evaluation of RSG-GAS purification system and pool warm water layer supplier performance

    International Nuclear Information System (INIS)

    Sudiyono; Suhadi; Diah-Erlina-Lestari

    2005-01-01

    Function of RSG-GAS purification system and warm water supplier (KBE 02) are to pick up dissolve activation result and another dirts of warm water layer. To keep quality of water at the decided level. The system is equipped by heater to supply warm water layer on the reactor pool surface the distribution is to reduce radiation level in the operation hall area a speciality on the reactor pool surface. Line KBE 02 tomord beam tube headitty system supplies water necessary to be shielding to beam tube in use off time. Of the RSG-GAS purification system and pool warm water layer performance date can be shown north of water is always in good condition. To require the dechded requirement. Resin live time is two years and then months

  1. Deep water convection and biogeochemical cycling of carbon in the Northern North Atlantic

    International Nuclear Information System (INIS)

    Buch, E.; Gissel Nielsen, T.; Lundsgaard, C.; Bendtsen, J.

    2001-01-01

    In 1998, the Danish Research Council launched the Global Change project 'Biochemical cycling of carbon and ocean circulation in the Northern North Atlantic'. The overall aim of the project was to describe the effect of high latitude carbon dynamics on the global ocean-atmosphere carbon system, in general, and on the atmospheric pCO 2 in particular. At present, knowledge concerning the seasonal differences in turnover rates of organic material in polar and sub-polar regions is limited. Thus, in order to achieve the aim of the project, it was necessary to obtain biological and chemical rate measurements for production and mineralization of dissolved and particulate organic material at high latitudes and relate these to ocean dynamics at different times of the year. This was investigated in the project by performing three cruises to the Greenland Sea area at different times of the year. The purpose of the present chapter is to give a review of: 1) The physical environment of the Northern North Atlantic (ocean circulation, deep convection, North Atlantic Oscillation) and its variability including the recent trends of importance to climate change. 2) The chemical and biological processes of importance to carbon cycle and the importance of the carbon cycle to our understanding of climate variability. Additionally preliminary results from the Danish global change investigation in the Greenland Sea will be presented. With regard to circulation it is concluded that the deep water in the Greenland Sea continues to warm up, indicating that the deep water formation in this area is reduced. The biological investigations are providing a highly needed basic knowledge of the structure and function of the pelagic food web as well as of the microbial food web of the intermediate and deep water. These studies form a basis for assessing the productivity, export mechanisms, mineralization rates and mineralization depth-scales in these areas. Especially the questions about the

  2. Global Warming, New Climate, New Atmospheric Circulation and New Water Cycle in North Africa

    Science.gov (United States)

    Karrouk, M. S.

    2017-12-01

    Global warming has now reached the energetic phase of H2O's return to the ground after the saturation of the atmosphere in evaporation since the 80s and 90s of the last century, which were characterized by severe droughts, mainly in Africa.This phase is the result of the accumulation of thermal energy exchanges in the Earth-Ocean-Atmosphere system that resulted in the thrust reversal of the energy balance toward the poles. This situation is characterized by a new thermal distribution: above the ocean, the situation is more in surplus compared to the mainland, or even opposite when the balance is negative on the land, and in the atmosphere, warm thermal advection easily reach the North Pole (planetary crests), as well as cold advection push deep into North Africa and the Gulf of Mexico (planetary valleys: Polar Vortex).This "New Ground Energy Balance" establishes a "New Meridian Atmospheric Circulation (MAC)" with an undulating character throughout the year, including the winter characterized by intense latitudinal very active energy exchanges between the surplus areas (tropical) and the deficit (polar) on the one hand, and the atmosphere, the ocean and the continent on the other.The excess radiation balance increases the potential evaporation of the atmosphere and provides a new geographical distribution of Moisture and Water worldwide: the excess water vapor is easily converted by cold advection (Polar Vortex) to heavy rains that cause floods or snow storms that paralyze the normal functioning of human activities, which creates many difficulties for users and leaves damage and casualties, but ensures water availability missing since a long time in many parts of the world, in Africa, Europe and America.The new thermal distribution reorganizes the geography of atmospheric pressure: the ocean energy concentration is transmitted directly to the atmosphere, and the excess torque is pushed northward. The Azores anticyclone is strengthened and is a global lock by the

  3. Sinking of Dense North Atlantic Waters in a Global Ocean Model : Location and Controls

    NARCIS (Netherlands)

    Katsman, C.A.; Drijfhout, SS; Dijkstra, H. A.; Spall, M. A.

    2018-01-01

    We investigate the characteristics of the sinking of dense waters in the North Atlantic Ocean that constitute the downwelling limb of the Atlantic Meridional Overturning Circulation (AMOC) as simulated by two global ocean models: an eddy-permitting model at 1/4° resolution and its coarser 1°

  4. Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters

    Science.gov (United States)

    Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. We hypothesize that this warming may be amplified in the shallow (<2m), nearshore portions ...

  5. Present status of fish culture using warm waste water from power plants

    International Nuclear Information System (INIS)

    1976-01-01

    The research of fish culture using warm waste water from power stations in Japan has history of over ten years. It is being gradually commercialized, but still various problems remain. Among the fish culture activities, those related to nuclear power generation are described as follows: Tokai ponds of Warm Water Fish Culture Development Society of Japan (culturing crimson sea bream, ear shell, flatfish, prawn, and eel); Fukui Prefectural Fisheries Experimental Station (culturing sweetfish and young yellowtail); and, Warm Water Utilization Center of Shizuoka Prefecture (culturing ear shell). (Mori, K.)

  6. Changing forest water yields in response to climate warming: results from long-term experimental watershed sites across North America

    Science.gov (United States)

    Irena F. Creed; Adam T. Spargo; Julia A. Jones; Jim M. Buttle; Mary B. Adams; Fred D. Beall; Eric G. Booth; John L. Campbell; Dave Clow; Kelly Elder; Mark B. Green; Nancy B. Grimm; Chelcy Miniat; Patricia Ramlal; Amartya Saha; Stephen Sebestyen; Dave Spittlehouse; Shannon Sterling; Mark W. Williams; Rita Winkler; Huaxia. Yao

    2014-01-01

    Climate warming is projected to affect forest water yields but the effects are expected to vary.We investigated how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long-term experimental catchments across Canada and the United States over 5-year cool and warm...

  7. Confluence and redistribution of Atlantic water in the Nansen, Amundsen and Makarov basins

    Directory of Open Access Journals (Sweden)

    U. Schauer

    Full Text Available The waters in the Eurasian Basin are conditioned by the confluence of the boundary flow of warm, saline Fram Strait water and cold low salinity water from the Barents Sea entering through the St. Anna Trough. Hydrographic sections obtained from RV Polarstern during the summer of 1996 (ACSYS 96 across the St. Anna Trough and the Voronin Trough in the northern Kara Sea and across the Nansen, Amundsen and Makarov basins allow for the determination of the water mass properties of the two components and the construction of a qualitative picture of the circulation both within the Eurasian Basin and towards the Canadian Basin. At the confluence north of the Kara Sea, the Fram Strait branch is displaced from the upper to the lower slope and it forms a sharp front to the Barents Sea water at depths between 100 m and greater than 1000 m. This front disintegrates downstream along the basin margin and the two components are largely mixed before the boundary current reaches the Lomonosov Ridge. Away from the continental slope, the presence of interleaving structures coherent over wide distances is consistent with low lateral shear. The return flow along the Nansen Gakkel Ridge, if present at all, seems to be slow and the cold water below a deep mixed layer there indicates that the Fram Strait Atlantic water was not covered with a halocline for about a decade. Anomalous water mass properties in the interior of the Eurasian Basin can be attributed to isolated lenses rather than to baroclinic flow cores. Eddies have probably detached from the front at the confluence and migrated into the interior of the basin. One deep (2500 m lens of Canadian Basin water, with an anticyclonic eddy signature, must have spilled through a gap of the Lomonosov Ridge. During ACSYS 96, no clear fronts between Eurasian and Canadian intermediate waters, such as those observed further north in 1991 and 1994, were found at the Siberian side of the Lomonosov Ridge. This indicates that

  8. Confluence and redistribution of Atlantic water in the Nansen, Amundsen and Makarov basins

    Directory of Open Access Journals (Sweden)

    U. Schauer

    2002-02-01

    Full Text Available The waters in the Eurasian Basin are conditioned by the confluence of the boundary flow of warm, saline Fram Strait water and cold low salinity water from the Barents Sea entering through the St. Anna Trough. Hydrographic sections obtained from RV Polarstern during the summer of 1996 (ACSYS 96 across the St. Anna Trough and the Voronin Trough in the northern Kara Sea and across the Nansen, Amundsen and Makarov basins allow for the determination of the water mass properties of the two components and the construction of a qualitative picture of the circulation both within the Eurasian Basin and towards the Canadian Basin. At the confluence north of the Kara Sea, the Fram Strait branch is displaced from the upper to the lower slope and it forms a sharp front to the Barents Sea water at depths between 100 m and greater than 1000 m. This front disintegrates downstream along the basin margin and the two components are largely mixed before the boundary current reaches the Lomonosov Ridge. Away from the continental slope, the presence of interleaving structures coherent over wide distances is consistent with low lateral shear. The return flow along the Nansen Gakkel Ridge, if present at all, seems to be slow and the cold water below a deep mixed layer there indicates that the Fram Strait Atlantic water was not covered with a halocline for about a decade. Anomalous water mass properties in the interior of the Eurasian Basin can be attributed to isolated lenses rather than to baroclinic flow cores. Eddies have probably detached from the front at the confluence and migrated into the interior of the basin. One deep (2500 m lens of Canadian Basin water, with an anticyclonic eddy signature, must have spilled through a gap of the Lomonosov Ridge. During ACSYS 96, no clear fronts between Eurasian and Canadian intermediate waters, such as those observed further north in 1991 and 1994, were found at the Siberian side of the Lomonosov Ridge. This indicates that

  9. Transport of Mars atmospheric water into high northern latitudes during a polar warming

    Science.gov (United States)

    Barnes, J. R.; Hollingsworth, J. L.

    1988-01-01

    Several numerical experiments were conducted with a simplified tracer transport model in order to attempt to examine the poleward transport of Mars atmospheric water during a polar warming like that which occurred during the winter solstice dust storm of 1977. The flow for the transport experiments was taken from numerical simulations with a nonlinear beta-plane dynamical model. Previous studies with this model have demonstrated that a polar warming having essential characteristics like those observed during the 1977 dust storm can be produced by a planetary wave mechanism analogous to that responsible for terrestrial sudden stratospheric warmings. Several numerical experiments intended to simulate water transport in the absence of any condensation were carried out. These experiments indicate that the flow during a polar warming can transport very substantial amounts of water to high northern latitudes, given that the water does not condense and fall out before reaching the polar region.

  10. Ecosystem responses to warming and watering in typical and desert steppes

    Science.gov (United States)

    Xu, Zhenzhu; Hou, Yanhui; Zhang, Lihua; Liu, Tao; Zhou, Guangsheng

    2016-10-01

    Global warming is projected to continue, leading to intense fluctuations in precipitation and heat waves and thereby affecting the productivity and the relevant biological processes of grassland ecosystems. Here, we determined the functional responses to warming and altered precipitation in both typical and desert steppes. The results showed that watering markedly increased the aboveground net primary productivity (ANPP) in a typical steppe during a drier year and in a desert steppe over two years, whereas warming manipulation had no significant effect. The soil microbial biomass carbon (MBC) and the soil respiration (SR) were increased by watering in both steppes, but the SR was significantly decreased by warming in the desert steppe only. The inorganic nitrogen components varied irregularly, with generally lower levels in the desert steppe. The belowground traits of soil total organic carbon (TOC) and the MBC were more closely associated with the ANPP in the desert than in the typical steppes. The results showed that the desert steppe with lower productivity may respond strongly to precipitation changes, particularly with warming, highlighting the positive effect of adding water with warming. Our study implies that the habitat- and year-specific responses to warming and watering should be considered when predicting an ecosystem’s functional responses under climate change scenarios.

  11. Changes in Bottom Water Physical Properties Above the Mid-Atlantic Ridge Flank in the Brazil Basin

    Science.gov (United States)

    Zhao, Jian; Thurnherr, Andreas M.

    2018-01-01

    Warming of abyssal waters in recent decades has been widely documented around the global ocean. Here repeat hydrographic data collected in 1997 and 2014 near a deep fracture zone canyon in the eastern Brazil Basin are used to quantify the long-term change. Significant changes are found in the Antarctic Bottom Water (AABW) within the canyon. The AABW in 2014 was warmer (0.08 ± 0.06°C), saltier (0.01 ± 0.005), and less dense (0.005 ± 0.004 kg m-3) than in 1997. In contrast, the change in the North Atlantic Deep Water has complicated spatial structure and is almost indistinguishable from zero at 95% confidence. The resulting divergence in vertical displacement of the isopycnals modifies the local density stratification. At its peak, the local squared buoyancy frequency (N2) near the canyon is reduced by about 20% from 1997 to 2014. Similar reduction is found in the basinwide averaged profiles over the Mid-Atlantic Ridge flank along 25°W in years 1989, 2005, and 2014. The observed changes in density stratification have important implications for internal tide generation and dissipation.

  12. Holocene Millennial-scale Surface and Bottom Water Variability, Feni Drift, NE Atlantic Ocean: Foraminiferal Assemblages

    Science.gov (United States)

    Lassen, S. J.; Richter, T. O.; de Stigter, H. C.; van Weering, T. C. E.; de Haas, H.

    A high-resolution sediment core from Feni Drift (ENAM9606, 56N 14W, 2543 m wa- ter depth) was investigated for planktonic and benthic foraminiferal assemblages dur- ing the last 12,000 years. During the Preboreal, peak abundances of T.quinqueloba indicate the passage of the Arctic front over the core site. Holocene planktonic foraminiferal assemblages indicate a gradual warming trend of surface water masses punctuated by a major cooling (8,200ky event s.l.), and possibly a slight cooling dur- ing the last 3,000 years. The interval from 10 to 5kyrs shows higher and fluctuating abundances of T.quinqueloba and G.bulloides, which suggest proximity of the subarc- tic front and enhanced spring blooms compared to the upper Holocene. Abundance peaks of N.pachyderma(s) and/or T.quinqueloba indicate a series of millennial-scale cooling events during the entire Holocene, which can be correlated to similar episodes previously described from other locations in the North Atlantic and Norwegian- Greenland Sea. Benthic foraminiferal assemblages indicate a gradual transition from seasonal, spring-bloom related food supply in the Lower Holocene (dominance of the phytodetritus species E.exigua) to possibly lower, but more sustained food supply in the Upper Holocene (dominance of C.obtusa and C.laevigata).

  13. Warming by immersion or exercise affects initial cooling rate during subsequent cold water immersion.

    Science.gov (United States)

    Scott, Chris G; Ducharme, Michel B; Haman, François; Kenny, Glen P

    2004-11-01

    We examined the effect of prior heating, by exercise and warm-water immersion, on core cooling rates in individuals rendered mildly hypothermic by immersion in cold water. There were seven male subjects who were randomly assigned to one of three groups: 1) seated rest for 15 min (control); 2) cycling ergometry for 15 min at 70% Vo2 peak (active warming); or 3) immersion in a circulated bath at 40 degrees C to an esophageal temperature (Tes) similar to that at the end of exercise (passive warming). Subjects were then immersed in 7 degrees C water to a Tes of 34.5 degrees C. Initial Tes cooling rates (initial approximately 6 min cooling) differed significantly among the treatment conditions (0.074 +/- 0.045, 0.129 +/- 0.076, and 0.348 +/- 0.117 degrees C x min(-1) for control, active, and passive warming conditions, respectively); however, secondary cooling rates (rates following initial approximately 6 min cooling to the end of immersion) were not different between treatments (average of 0.102 +/- 0.085 degrees C x min(-1)). Overall Tes cooling rates during the full immersion period differed significantly and were 0.067 +/- 0.047, 0.085 +/- 0.045, and 0.209 +/- 0.131 degrees C x min(-1) for control, active, and passive warming, respectively. These results suggest that prior warming by both active and, to a greater extent, passive warming, may predispose a person to greater heat loss and to experience a larger decline in core temperature when subsequently exposed to cold water. Thus, functional time and possibly survival time could be reduced when cold water immersion is preceded by whole-body passive warming, and to a lesser degree by active warming.

  14. Return of naturally sourced Pb to Atlantic surface waters

    NARCIS (Netherlands)

    Bridgestock, L.; van de Flierdt, T.; Rehkämper, M.; Paul, P.; Middag, R.; Milne, A.; Lohan, M.C.; Baker, A.; Chance, R.; Khondoker, R.; Strekopytov, S.; Humphreys-Williams, E.; Achterberg, E.P.; Rijkenberg, M.J.A.; Gerringa, L.J.A.; De Baar, H.J.W.

    2016-01-01

    Anthropogenic emissions completely overwhelmed natural marine lead (Pb) sources duringthe past century, predominantly due to leaded petrol usage. Here, based on Pb isotopemeasurements, we reassess the importance of natural and anthropogenic Pb sources to thetropical North Atlantic following the

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  16. Atlantic Water transformation in the Nordic Seas and its influence on the export rate of the Overflow Waters

    Science.gov (United States)

    Garcia Quintana, Yarisbel; Wiesner, Pia; Hu, Xianmin; Myers, Paul

    2017-04-01

    The Nordic Seas (NS) are the main gateway between the Arctic and the Atlantic Oceans. The basin can be considered as the headwaters for the Meridional Overturning Circulation (MOC), for it is there that the Denmark Strait Overflow Water (DSOW) and the Iceland-Scotland Overflow Water (ISOW) acquire their properties. Their inflow into the North Atlantic Ocean occurs across the Greenland-Scotland ridge. Together with Labrador Sea Water, DSOW and ISOW are the main components of the North Atlantic Deep Water (NADW), which ventilates the lower limb of the Atlantic MOC. In spite recent studies exploring the export rate and later pathways of the overflows, the question about what drives them, remains. Here we explore the transformation of the Atlantic Water (AW) as it enters the NS through Denmark Strait, Iceland Faroe Ridge and Faroe Schotland Channel, as well as its pathways within the basin. To do so, we use an eddy-permitting ocean general circulation model run over the period 2002 to 2015. Two different approaches are used to track the AW transformation in the NS: the well-tested off-line Lagrangian tool ARIANE and on-line passive tracers. In both cases we use the same definition of AW to tag its inflow through the three entering sections. The overflows directly impact circulation and water properties in much of the deep Atlantic Ocean, thus a better understanding of the physical processes behind their variability is crucial a asset.

  17. The establishment of Atlantic Water transport as a topographically trapped slope current off Scotland

    Directory of Open Access Journals (Sweden)

    Qin Zhou

    2013-05-01

    Full Text Available Atlantic Water, with its origin in the western Atlantic, enters the Nordic Seas partly as a barotropic current following the continental slope. This water mass is carried across the Atlantic by the baroclinic North Atlantic Current (NAC. When the NAC meets the continental slope at the east side of the Atlantic, some of the transport is converted to barotropic transport over the slope before continuing northward. Here, we show that this baroclinic to barotropic conversion is in agreement with geostrophic theory. Historical observations show that the transport of the slope current increases significantly from the Rockall Channel (RC to the Faroe–Shetland Channel (FSC. Geostrophy predicts that with a northward decreasing buoyancy, baroclinic currents from the west will be transferred into northward topographically steered barotropic flow. We use hydrographic data from two sections crossing the continental slope, one located in the RC and another in the FSC, to estimate baroclinic and barotropic transport changes over the slope, within the framework of geostrophic dynamics. Our results indicate that ~1 Sv of the cross-slope baroclinic flow is mainly converted to northward barotropic transport above the 200–500m isobaths, which is consistent with observed transport changes between the RC and the FSC. Similar processes are also likely to occur further south, along the eastern Atlantic margin. This shows that AW within the slope current in the FSC is derived from both the eastern and the western Atlantic, in agreement with earlier studies of AW inflow to the Nordic Seas.

  18. Warming combined with more extreme precipitation regimes modifies the water sources used by trees.

    Science.gov (United States)

    Grossiord, Charlotte; Sevanto, Sanna; Dawson, Todd E; Adams, Henry D; Collins, Adam D; Dickman, Lee T; Newman, Brent D; Stockton, Elizabeth A; McDowell, Nate G

    2017-01-01

    The persistence of vegetation under climate change will depend on a plant's capacity to exploit water resources. We analyzed water source dynamics in piñon pine and juniper trees subjected to precipitation reduction, atmospheric warming, and to both simultaneously. Piñon and juniper exhibited different and opposite shifts in water uptake depth in response to experimental stress and background climate over 3 yr. During a dry summer, juniper responded to warming with a shift to shallow water sources, whereas piñon pine responded to precipitation reduction with a shift to deeper sources in autumn. In normal and wet summers, both species responded to precipitation reduction, but juniper increased deep water uptake and piñon increased shallow water uptake. Shifts in the utilization of water sources were associated with reduced stomatal conductance and photosynthesis, suggesting that belowground compensation in response to warming and water reduction did not alleviate stress impacts for gas exchange. We have demonstrated that predicted climate change could modify water sources of trees. Warming impairs juniper uptake of deep sources during extended dry periods. Precipitation reduction alters the uptake of shallow sources following extended droughts for piñon. Shifts in water sources may not compensate for climate change impacts on tree physiology. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  19. Warm-water coral reefs and climate change.

    Science.gov (United States)

    Spalding, Mark D; Brown, Barbara E

    2015-11-13

    Coral reefs are highly dynamic ecosystems that are regularly exposed to natural perturbations. Human activities have increased the range, intensity, and frequency of disturbance to reefs. Threats such as overfishing and pollution are being compounded by climate change, notably warming and ocean acidification. Elevated temperatures are driving increasingly frequent bleaching events that can lead to the loss of both coral cover and reef structural complexity. There remains considerable variability in the distribution of threats and in the ability of reefs to survive or recover from such disturbances. Without significant emissions reductions, however, the future of coral reefs is increasingly bleak. Copyright © 2015, American Association for the Advancement of Science.

  20. Ecosystem responses to warming and watering in typical and desert steppes

    OpenAIRE

    Zhenzhu Xu; Yanhui Hou; Lihua Zhang; Tao Liu; Guangsheng Zhou

    2016-01-01

    Global warming is projected to continue, leading to intense fluctuations in precipitation and heat waves and thereby affecting the productivity and the relevant biological processes of grassland ecosystems. Here, we determined the functional responses to warming and altered precipitation in both typical and desert steppes. The results showed that watering markedly increased the aboveground net primary productivity (ANPP) in a typical steppe during a drier year and in a desert steppe over two ...

  1. Strong Flows of Bottom Water in Abyssal Channels of the Atlantic

    Science.gov (United States)

    Morozov, E. G.

    Analysis of bottom water transport through the abyssal channels of the Atlantic Ocean is presented. The study is based on recent observations in the Russian expeditions and historical data. A strong flow of Antarctic Bottom Water from the Argentine Basin to the Brazil Basin through the Vema Channel is observed on the basis of lowered profilers and anchored buoys with current meters. The further flow of bottom water in the Brazil Basin splits in the northern part of the basin. Part of the bottom water flows to the East Atlantic through the Romanche and Chain fracture zones. The other part follows the bottom topography and flows to the northwester into the North American Basin. Part of the northwesterly flow propagates through the Vema Fracture Zone into the Northeastern Atlantic. This flow generally fills the bottom layer in the Northeastern Atlantic basins. The flows of bottom waters through the Romanche and Chain fracture zones do not spread to the Northeast Atlantic due to strong mixing in the equatorial zone and enhanced transformation of bottom water properties.

  2. Predicting the occurrence of cold water patches at intermittent and ephemeral tributary confluences with warm rivers

    Science.gov (United States)

    Small, cold tributary streams can provide important thermal refuge habitat for cold-water fishes such as Pacific salmon (Oncorhynchus spp.) residing in warm, downstream receiving waters. We investigated the potential function of small perennial and non-perennial tributary stream...

  3. Coral mucus fuels the sponge loop in warm- and cold-water coral reef ecosystems

    NARCIS (Netherlands)

    Rix, L.; de Goeij, J.M.; Mueller, C.E.; Struck, U.; Middelburg, J.J.; van Duyl, F.C.; Al-Horani, F.A.; Wild, C.; Naumann, M.S.; Van Oevelen, D.

    2016-01-01

    Shallow warm-water and deep-sea cold-water corals engineer the coral reef framework and fertilize reef communities by releasing coral mucus, a source of reef dissolved organic matter (DOM). By transforming DOM into particulate detritus, sponges play a key role in transferring the energy and

  4. Ecosystem maturation follows the warming of the Arctic fjords

    OpenAIRE

    Jan Marcin Węsławski; Friedrich Buchholz; Marta Głuchowska; Agata Weydmann

    2017-01-01

    Two fjords in West Spitsbergen (Hornsund 77°N and Kongsfjorden 79°N) differ with regard to their exposure towards increasingly warm Atlantic water inflow. Hornsund remains in many respects cooler than Kongsfjorden (on average 2°C SST in summer) and is less influenced by warmer and more saline Atlantic waters. Reported changes in the physical environment (temperature rise, freshwater inflow, salinity drop, turbidity, fast-ice reduction, coastal change) are discussed in the context of biologica...

  5. Assessing water quality of the Chesapeake Bay by the impact of sea level rise and warming

    Science.gov (United States)

    Wang, P.; Linker, L.; Wang, H.; Bhatt, G.; Yactayo, G.; Hinson, K.; Tian, R.

    2017-08-01

    The influence of sea level rise and warming on circulation and water quality of the Chesapeake Bay under projected climate conditions in 2050 were estimated by computer simulation. Four estuarine circulation scenarios in the estuary were run using the same watershed load in 1991-2000 period. They are, 1) the Base Scenario, which represents the current climate condition, 2) a Sea Level Rise Scenario, 3) a Warming Scenario, and 4) a combined Sea Level Rise and Warming Scenario. With a 1.6-1.9°C increase in monthly air temperatures in the Warming Scenario, water temperature in the Bay is estimated to increase by 0.8-1°C. Summer average anoxic volume is estimated to increase 1.4 percent compared to the Base Scenario, because of an increase in algal blooms in the spring and summer, promotion of oxygen consumptive processes, and an increase of stratification. However, a 0.5-meter Sea Level Rise Scenario results in a 12 percent reduction of anoxic volume. This is mainly due to increased estuarine circulation that promotes oxygen-rich sea water intrusion in lower layers. The combined Sea Level Rise and Warming Scenario results in a 10.8 percent reduction of anoxic volume. Global warming increases precipitation and consequently increases nutrient loads from the watershed by approximately 5-7 percent. A scenario that used a 10 percent increase in watershed loads and current estuarine circulation patterns yielded a 19 percent increase in summer anoxic volume, while a scenario that used a 10 percent increase in watershed loads and modified estuarine circulation patterns by the aforementioned sea level rise and warming yielded a 6 percent increase in summer anoxic volume. Impacts on phytoplankton, sediments, and water clarity were also analysed.

  6. The spatial distribution of silicoflagellates in the region of the Gulf Stream warm-core ring 82B: application to water mass tracer studies

    Science.gov (United States)

    Takahashi, Kozo; Blackwelder, Patricia L.

    1992-03-01

    To delineate potential water mass affinities, we investigated silicoflagellates from the region of Gulf Stream warm-core ring (WCR) 82B in the northwestern Atlantic. Silicoflagellates from 202 samples from N-S and an E-W transects across WCR 82B during late April were analysed. Shelf to Sargasso Sea transects, one completed in early May and the other in June 1982 were also examined. Eight to 11 vertical profiles to 200 m comprised each of the transects. Six taxa of silicoflagellates were found in the samples studied and a total of more than 8000 specimens were encountered. Three major taxa dominated standing stocks: Distephanus speculum, Dictyocha messanensis (intermediate-sized form) and D. mandrai. D. speculum, considered a cold-water taxon in the literature, showed a higher standing stock in the cooler high-velocity region (HVR) of the warm-core ring, continental shelf (SH) and slope (SL) waters. Fewer were present in the wanner ring center (RC), Gulf Stream (GS) and Sargasso Sea (SS). D. mandrai showed a similar distribution to that of D. speculum, but its preference for slightly warmer waters (>~10°C) was noted. In contrast, Dictyocha messanensis (intermediate-sized) and Distephanus pulchra, known to be warm-water taxa, were relatively abundant in the warm ring center. In contrast to standing stock data, ratios between cold- and warm-water taxa correlate well with temperature and salinity in the warm-core ring. Since these ratios are not effected by convective loss, they are excellent water mass tracers in this system. Distribution of the silicoflagellate taxa suggests that WCR82B April had a higher affinity with the Gulf Stream than the Sargasso Sea. Scores derived from factor analysis indicate that silicoflagellate species distributions are highly correlative with water masses. This was evident from correlations with temperature, salinity and with distance from ring center. Nutrients were generally not correlated with species data. This may be due to deep

  7. Ventimolina stellata gen. et sp. nov. (Haptophyta, Papposphaeraceae) from warm water regions

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette B.; Cros, Lluïsa

    2015-01-01

    It has been known for some time that the distinctive polar weakly calcified coccolithophores are also present in samples from lower latitudes. While polar species may actually have a geographic range that vastly extends beyond the polar realms, it is often the case that the warm water regions...... contribute species that can be allocated to genera previously described based on polar material. We are currently in the process of formally dealing with the warm water species diversity affiliated with the family Papposphaeraceae. In this paper we describe a new genus and species Ventimolina stellata based...

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

    Science.gov (United States)

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

    2018-01-01

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

  9. Scorched mussels (Brachidontes spp., Bivalvia: Mytilidae) from the tropical and warm-temperate southwestern Atlantic: the role of the Amazon River in their speciation.

    Science.gov (United States)

    Trovant, Berenice; Basso, Néstor G; Orensanz, José María; Lessa, Enrique P; Dincao, Fernando; Ruzzante, Daniel E

    2016-03-01

    Antitropicality is a distribution pattern where closely related taxa are separated by an intertropical latitudinal gap. Two potential examples include Brachidontes darwinianus (south eastern Brazil to Uruguay), considered by some authors as a synonym of B. exustus (Gulf of Mexico and the Caribbean), and B. solisianus, distributed along the Brazilian coast with dubious records north of the intertropical zone. Using two nuclear (18S and 28S rDNA) and one mitochondrial gene (mtDNA COI), we aimed to elucidate the phylogeographic and phylogenetic relationships among the scorched mussels present in the warm-temperate region of the southwest Atlantic. We evaluated a divergence process mediated by the tropical zone over alternative phylogeographic hypotheses. Brachidontes solisianus was closely related to B. exustus I, a species with which it exhibits an antitropical distribution. Their divergence time was approximately 2.6 Ma, consistent with the intensification of Amazon River flow. Brachidontes darwinianus, an estuarine species is shown here not to be related to this B. exustus complex. We suspect ancestral forms may have dispersed from the Caribbean to the Atlantic coast via the Trans-Amazonian seaway (Miocene). The third species, B rodriguezii is presumed to have a long history in the region with related fossil forms going back to the Miocene. Although scorched mussels are very similar in appearance, their evolutionary histories are very different, involving major historical contingencies as the formation of the Amazon River, the Panama Isthmus, and the last marine transgression.

  10. Classification of a hypervirulent Aeromonas hydrophila pathotype responsible for epidemic outbreaks in warm-water fishes

    Science.gov (United States)

    Lineages of hypervirulent Aeromonas hydrophila (vAh) are the cause of persistent outbreaks of motile Aeromonas septicemia in warm-water fishes worldwide. Over the last decade, this virulent lineage of A. hydrophila has resulted in annual losses of millions of tons of farmed carp and catfish in the P...

  11. Proposal of computation chart for general use for diffusion prediction of discharged warm water

    International Nuclear Information System (INIS)

    Wada, Akira; Kadoyu, Masatake

    1976-01-01

    The authors have developed the unique simulation analysis method using the numerical models for the prediction of discharged warm water diffusion. At the present stage, the method is adopted for the precise analysis computation in order to make the prediction of the diffusion of discharged warm water at each survey point, but instead of this method, it is strongly requested that some simple and easy prediction methods should be established. For the purpose of meeting this demand, in this report, the computation chart for general use is given to predict simply the diffusion range of discharged warm water, after classifying the semi-infinite sea region into several flow patterns according to the sea conditions and conducting the systematic simulation analysis with the numerical model of each pattern, respectively. (1) Establishment of the computation conditions: The special sea region was picked up as the area to be investigated, which is semi-infinite facing the outer sea and along the rectilineal coast line from many sea regions surrounding Japan, and from the viewpoint of the flow and the diffusion characteristics, the sea region was classified into three patterns. 51 cases in total various parameters were obtained, and finally the simulation analysis was performed. (2) Drawing up the general use chart: 28 sheets of the computation chart for general use were drawn, which are available for computing the approximate temperature rise caused by the discharged warm water diffusion. The example of Anegasaki Thermal Power Station is given. (Kako, I.)

  12. Observed and Modeled Pathways of the Iceland Scotland Overflow Water in the eastern North Atlantic

    Science.gov (United States)

    Zou, Sijia; Lozier, Susan; Zenk, Walter; Bower, Amy; Johns, William

    2017-04-01

    The Iceland Scotland Overflow Water (ISOW), one of the major components of the lower limb of the Atlantic Meridional Overturning Circulation (AMOC), is formed in the Nordic Seas and enters the eastern North Atlantic subpolar gyre via the Iceland-Scotland sill. After entraining the ambient waters, the relatively homogeneous ISOW spreads southward into the North Atlantic. An understanding of the distribution and variability of the spreading pathways of the ISOW is fundamental to our understanding of AMOC structure and variability. Three major ISOW pathways have been identified in the eastern North Atlantic by previous studies: 1) across the Reykjanes Ridge via deep gaps, 2) through the Charlie Gibbs Fracture Zone, and 3) southward along the eastern flank of the Mid Atlantic Ridge (MAR). However, most of these studies were conducted using an Eulerian frame with limited observations, especially for the third pathway along the eastern flank of the MAR. In this work, we give a comprehensive description of ISOW pathways in the Eulerian and Lagrangian frames, quantify the relative importance of each pathway and examine the temporal variability of these pathways. Our study distinguishes itself from past studies by using both Eulerian (current meter data) and Lagrangian (eddy-resolving RAFOS float data) observations in combination with modeling output (1/12° FLAME) to describe ISOW spreading pathways and their variability.

  13. Cardiovascular response to apneic immersion in cool and warm water

    Science.gov (United States)

    Folinsbee, L.

    1974-01-01

    The influence of prior exposure to cool water and the influence of lung volume on the responses to breath holding were examined. The bradycardia and vasoconstriction that occur during breath-hold diving in man are apparently the resultant of stimuli from apnea, relative expansion of the thorax, lung volume, esophageal pressure, face immersion, and thermal receptor stimulation. It is concluded that the bradycardia and vasoconstriction associated with breath holding during body immersion are not attenuated by a preexisting bradycardia and vasoconstriction due to cold.

  14. Partitioning the effects of Global Warming on the Hydrological Cycle with Stable Isotopes in Water Vapor

    Science.gov (United States)

    Dee, S. G.; Russell, J. M.; Nusbaumer, J. M.; Konecky, B. L.; Buenning, N. H.; Lee, J. E.; Noone, D.

    2016-12-01

    General circulation models (GCMs) suggest that much of the global hydrological cycle's response to anthropogenic warming will be caused by increased lower-tropospheric water vapor concentrations and associated feedbacks. However, fingerprinting changes in the global hydrological cycle due to anthropogenic warming remains challenging. Held and Soden (2006) predicted that as lower-tropospheric water vapor increases, atmospheric circulation will weaken as climate warms to maintain the surface energy budget. Unfortunately, the strength of this feedback and the fallout for other branches of the hydrological cycle is difficult to constrain in situ or with GCMs alone. We demonstrate the utility of stable hydrogen isotope ratios in atmospheric water vapor to quantitatively trace changes in atmospheric circulation and convective mass flux in a warming world. We compare water isotope-enabled GCM experiments for control (present-day) CO2 vs. high CO2(2x, 4x) atmospheres in two GCMs, IsoGSM and iCAM5. We evaluate changes in the distribution of water vapor, vertical velocity (omega), and the stream function between these experiments in order to identify spatial patterns of circulation change over the tropical Pacific (where vertical motion is strong) and map the δD of water vapor associated with atmospheric warming. We also probe the simulations to isolate isotopic signatures associated with water vapor residence time, precipitation efficiency, divergence, and cloud physics. We show that there are robust mechanisms that moisten the troposphere and weaken convective mass flux, and that these mechanisms can be tracked using the δD of water vapor. Further, we find that these responses are most pronounced in the upper troposphere. These findings provide a framework to develop new metrics for the detection of global warming impacts to the hydrological cycle. Further, currently available satellite missions measure δD in the atmospheric boundary layer, the free atmosphere, or the

  15. A preliminary study of the tropical water cycle and its sensitivity to surface warming

    Science.gov (United States)

    Lau, K. M.; Sui, C. H.; Tao, W. K.

    1993-01-01

    The Goddard Cumulus Ensemble Model (GCEM) has been used to demonstrate that cumulus-scale dynamics and microphysics play a major role in determining the vertical distribution of water vapor and clouds in the tropical atmosphere. The GCEM is described and is the basic structure of cumulus convection. The long-term equilibrium response to tropical convection to surface warming is examined. A picture of the water cycle within tropical cumulus clusters is developed.

  16. Revised estimate for the radiocarbon age of North Atlantic deep water

    International Nuclear Information System (INIS)

    Broecker, W.S.

    1979-01-01

    The extent to which the admixture of water of Antarctic origin influences the 14 C/C ratio in North Atlantic deep water (NADW) has been heretofore underestimated. When this correction is properly made, a ventilation time for the deep western Atlantic is reduced to only about 100 years. The production rate of the northern component of NADW entering the western basin must be of the order of 30 Sv. If this northern component water is assumed to be the major supplier of new 14 C to the deep sea, the carbon isotope ventilation time of the world deep ocean must be of the order of 900 years. However, since the new deep waters formed around the perimeter of the Antarctic are thought to enter the deep sea at a rate of about 20 Sv, the water ventilation time for the deep sea is of the order of 550 years

  17. Transport of Antarctic bottom water through the Kane Gap, tropical NE Atlantic Ocean

    NARCIS (Netherlands)

    Morozov, E.G.; Tarakanov, R.Y.; van Haren, H.

    2013-01-01

    We study low-frequency properties of the Antarctic Bottom Water (AABW) flow through the Kane Gap (9° N) in the Atlantic Ocean. The measurements in the Kane Gap include five visits with CTD (Conductivity-Temperature-Depth) sections in 2009–2012 and a year-long record of currents on a mooring using

  18. Distribution and drift of Atlantic cod ( Gadus morhua ) eggs and larvae in Greenland offshore waters

    DEFF Research Database (Denmark)

    Wieland, Kai; Hovgård, Holger

    2002-01-01

    Catches of Atlantic cod (Gadus morhua) eggs and larvae from 45 national and international ichthyoplankton surveys conducted in Greenland offshore waters during the period 1950 to 1984 have been compiled and re-analysed. Southeast and Southwest Greenland were identified as im- portant spawning areas...

  19. Atlantic salmon breeding program at the National Cold Water Marine Aquaculture Center

    Science.gov (United States)

    The USDA-ARS National Cold Water Marine Aquaculture Center (NCWMAC) in Franklin, ME has been supporting the U.S. coldwater marine aquaculture industry for the past thirteen years by developing a genetically improved North American Atlantic salmon. The St. John's River stock was chosen as the focal ...

  20. Update to the Atlantic salmon breeding program at the National Cold Water Marine Aquaculture Center

    Science.gov (United States)

    The USDA-ARS National Cold Water Marine Aquaculture Center (NCWMAC) in Franklin, ME has been supporting the U.S. coldwater marine aquaculture industry for the past thirteen years by developing a genetically improved North American Atlantic salmon. The St. John's River stock was chosen as the focal ...

  1. Distribution of oxygen isotopes in the water masses of Drake Passage and the South Atlantic

    Science.gov (United States)

    Meredith, Michael P.; Grose, Katie E.; McDonagh, Elaine L.; Heywood, Karen J.; Frew, Russell D.; Dennis, Paul F.

    1999-09-01

    Measurements of the ratio of stable isotopes of oxygen (18O and 16O) from samples collected on World Ocean Circulation Experiment sections SR1b (eastern Drake Passage) and A11 (Punta Arenas to Cape Town) are used, together with hydrographic data, to deduce information about the formation and variability of South Atlantic and Southern Ocean water masses. The Drake Passage surface waters south of the Polar Front (PF) are isotopically light (δ18O around -0.4‰) owing to the influence of meteoric waters. The salinity and δ18O of the A11 surface waters yield an apparent freshwater end-member which is much isotopically lighter than the local precipitation, thus advection of these waters from farther south dominates over local effects in determining the surface water properties. The Drake Passage section shows unusual proximity of the two main fronts of the Antarctic Circumpolar Current (the PF and Subantarctic Front (SAF)), and we observe cold, fresh, and isotopically light water derived from the temperature-minimum Winter Water at the SAF. This water is of the correct density to freshen the intermediate water north of the SAF and thus play a role in the formation of the comparatively fresh Antarctic Intermediate Water (AAIW) of the South Atlantic. This confirms the role of Antarctic water in forming the South Atlantic variety of AAIW. Across the A11 section the oxygen isotope and salinity data at the AAIW core show very similar traces, with waters in the Malvinas Current loop showing lowest values of both. At the eastern boundary of the South Atlantic, the input of Red Sea Water from east of South Africa is observed via the presence of anomalously isotopically heavy AAIW. We deduce potentially significant temporal variability in the isotopic composition of Weddell Sea Deep Water (WSDW) by comparing the Drake Passage data to earlier data covering the outflow of the Weddell Sea. The A11 data show WSDW consistent with such variability, indicating that its effects could

  2. Ground-water flow and quality in the Atlantic City 800-foot sand, New Jersey

    Science.gov (United States)

    McAuley, Steven D.; Barringer, Julia L.; Paulachok, Gary N.; Clark, Jeffrey S.; Zapecza, Otto S.

    2001-01-01

    The regional, confined Atlantic City 800-foot sand is the principal source of water supply for coastal communities of southern New Jersey. In response to extensive use of the aquifer--nearly 21 million gallons per day in 1986--water levels have declined to about 100 feet below sea level near Atlantic City and remain below sea level throughout the coastal areas of southern New Jersey, raising concerns about the potential for saltwater intrusion into well fields. Water levels in the Atlantic City 800-foot sand have declined in response to pumping from the aquifer since the 1890's. Water levels in the first wells drilled into the Atlantic City 800-foot sand were above land surface, and water flowed continuously from the wells. By 1986, water levels were below sea level throughout most of the coastal areas. Under current conditions, wells near the coast derive most of their supply from lateral flow contributed from the unconfined part of the aquifer northwest of the updip limit of the confining unit that overlies the Atlantic City 800- foot sand. Ground water also flows laterally from offshore areas and leaks vertically through the overlying and underlying confining units into the Atlantic City 800-foot sand. The decline in water levels upsets the historical equilibrium between freshwater and ancient saltwater in offshore parts of the aquifer and permits the lateral movement of saltwater toward pumping centers. The rate of movement is accelerated as the decline in water levels increases. The chloride concentration of aquifer water 5.3 miles offshore of Atlantic City was measured as 77 mg/L (milligrams per liter) in 1985 at a U.S. Geological Survey observation well. Salty water has also moved toward wells in Cape May County. The confined, regional nature of the Atlantic City 800-foot sand permits water levels in Cape May County to decline in response to pumping in Atlantic County and vice versa. Historically, chloride concentrations as great as 1 ,510 mg/L have been

  3. Changing forest water yields in response to climate warming: results from long-term experimental watershed sites across North America

    Science.gov (United States)

    Creed, Irena F; Spargo, Adam T; Jones, Julia A; Buttle, Jim M; Adams, Mary B; Beall, Fred D; Booth, Eric G; Campbell, John L; Clow, Dave; Elder, Kelly; Green, Mark B; Grimm, Nancy B; Miniat, Chelcy; Ramlal, Patricia; Saha, Amartya; Sebestyen, Stephen; Spittlehouse, Dave; Sterling, Shannon; Williams, Mark W; Winkler, Rita; Yao, Huaxia

    2014-01-01

    Climate warming is projected to affect forest water yields but the effects are expected to vary. We investigated how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long-term experimental catchments across Canada and the United States over 5-year cool and warm periods. Using the theoretical framework of the Budyko curve, we calculated the effects of climate warming on the annual partitioning of precipitation (P) into evapotranspiration (ET) and water yield. Deviation (d) was defined as a catchment's change in actual ET divided by P [AET/P; evaporative index (EI)] coincident with a shift from a cool to a warm period – a positive d indicates an upward shift in EI and smaller than expected water yields, and a negative d indicates a downward shift in EI and larger than expected water yields. Elasticity was defined as the ratio of interannual variation in potential ET divided by P (PET/P; dryness index) to interannual variation in the EI – high elasticity indicates low d despite large range in drying index (i.e., resilient water yields), low elasticity indicates high d despite small range in drying index (i.e., nonresilient water yields). Although the data needed to fully evaluate ecosystems based on these metrics are limited, we were able to identify some characteristics of response among forest types. Alpine sites showed the greatest sensitivity to climate warming with any warming leading to increased water yields. Conifer forests included catchments with lowest elasticity and stable to larger water yields. Deciduous forests included catchments with intermediate elasticity and stable to smaller water yields. Mixed coniferous/deciduous forests included catchments with highest elasticity and stable water yields. Forest type appeared to influence the resilience of catchment water yields to climate warming, with conifer and deciduous catchments more susceptible to

  4. Millennium scale radiocarbon variations in Eastern North Atlantic thermocline waters: 0-7000 years

    Energy Technology Data Exchange (ETDEWEB)

    Frank, N.; Tisnerat-Laborde, N.; Hatte, C. [LSCE, F-91190 Gif Sur Yvette, (France); Colin, C. [Univ Paris 11, IDES, Orsay, (France); Dottori, M.; Reverdin, G. [Univ Paris 06, LOCEAN, F-75252 Paris, (France)

    2009-07-01

    Complete text of publication follows: Deep water corals are exceptional archives of modern and past ocean circulation as combined U-series and radiocarbon dating allows to reconstruct seawater radiocarbon. Here we present thermocline water radiocarbon concentrations that have been reconstructed for the past {approx} 7000 years for the eastern north Atlantic, based on deep-water corals from Rockall Bank and Porcupine Seabight. We find that thermocline water radiocarbon values follow overall the mean atmospheric long term trend with an average offset of {Delta}{sup 14}C between intermediate water and atmosphere of -55{+-}5 per thousand until 1960 AD. Residual variations are strong ({+-}25 per thousand) over the past 7000 years and there is first evidence that those are synchronous to millennium scale climate variability. Over the past 60 years thermocline water radiocarbon values increase due to the penetration of bomb-radiocarbon into the upper intermediate ocean. Radiocarbon increases by {Delta}{sup 14}C of +95 per thousand compared to +210 per thousand for eastern North Atlantic surface waters. Moreover, bomb-radiocarbon penetration to thermocline depth occurs with a delay of {approx} 10-15 years. Based on high resolution ocean circulation models we suggest that radiocarbon changes at upper intermediate depth are today barely affected by vertical mixing and represent more likely variable advection and mixing of water masses from the Labrador Sea and the temperate Atlantic (including Mediterranean outflow water). Consequently, we assume that residual radiocarbon variations over the past 7000 years reflect millennium scale variability of the Atlantic sub-polar and sub-tropical gyres

  5. Grey mullet (Mugilidae) as possible indicators of global warming in South African estuaries and coastal waters.

    Science.gov (United States)

    James, Nicola C; Whitfield, Alan K; Harrison, Trevor D

    2016-12-01

    The grey mullet usually occur in large numbers and biomass in the estuaries of all three South African biogeographic regions, thus making it an ideal family to use in terms of possibly acting as an environmental indicator of global warming. In this analysis the relative estuarine abundance of the dominant three groups of mugilids, namely tropical, warm-water and cool-water endemics, were related to sea surface coastal temperatures. The study suggests a strong link between temperature and the distribution and abundance of the three mullet groups within estuaries and indicates the potential of this family to act as an indicator for future climate change within these systems and adjacent coastal waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean

    DEFF Research Database (Denmark)

    He, Peng; Hou, Xiaolin; Aldahan, Ala

    2013-01-01

    Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations of the is...... 129I in ocean environments and impact on climate at the ocean boundary layer.......Concentrations and species of iodine isotopes (127I and 129I) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic 129I in the Arctic Ocean and the Nordic Seas, concentrations...... of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on 129I and 127I, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30° and 50°N. The results show iodate as the predominant species in the analyzed marine waters...

  7. Microbial ecology of deep-water mid-Atlantic canyons

    Science.gov (United States)

    Kellogg, Christina A.

    2011-01-01

    The research described in this fact sheet will be conducted from 2012 to 2014 as part of the U.S. Geological Survey's DISCOVRE (DIversity, Systematics, and COnnectivity of Vulnerable Reef Ecosystems) Program. This integrated, multidisciplinary effort will be investigating a variety of topics related to unique and fragile deep-sea ecosystems from the microscopic level to the ecosystem level. One goal is to improve understanding, at the microbiological scale, of the benthic communities (including corals) that reside in and around mid-Atlantic canyon habitats and their associated environments. Specific objectives include identifying and characterizing the microbial associates of deep-sea corals, characterizing the microbial biofilms on hard substrates to better determine their role in engineering the ecosystem, and adding a microbial dimension to benthic community structure and function assessments by characterizing micro-eukaryotes, bacteria, and archaea in deep-sea sediments.

  8. Sensitivity of North Atlantic subpolar gyre and overturning to stratification-dependent mixing: response to global warming

    Energy Technology Data Exchange (ETDEWEB)

    Marzeion, Ben [Massachusetts Institute of Technology, EAPS, Cambridge, MA (United States); Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research, Bergen (Norway); University of Innsbruck, Tropical Glaciology Group, Institute of Geography, Innsbruck (Austria); Levermann, Anders [Potsdam University, Earth System Analysis, Potsdam Institute for Climate Impact Research and Institute of Physics, Potsdam (Germany); Mignot, Juliette [Universite Pierre et Marie Curie, LOCEAN, Paris (France)

    2010-04-15

    We use a reduced complexity climate model with a three-dimensional ocean component and realistic topography to investigate the effect of stratification-dependent mixing on the sensitivity of the North Atlantic subpolar gyre (SPG), and the Atlantic meridional overturning circulation (AMOC), to idealized CO{sub 2} increase and peaking scenarios. The vertical diffusivity of the ocean interior is parameterized as {kappa} {proportional_to} N {sup -{alpha}}, where N is the local buoyancy frequency. For all parameter values 0 {<=} {alpha} {<=} 3, we find the SPG, and subsequently the AMOC, to weaken in response to increasing CO{sub 2} concentrations. The weakening is significantly stronger for {alpha} {>=} {alpha}{sub cr} {approx} 1.5. Depending on the value of {alpha}, two separate model states develop. These states remain different after the CO{sub 2} concentration is stabilized, and in some cases even after the CO{sub 2} concentration has been decreased again to the pre-industrial level. This behaviour is explained by a positive feedback between stratification and mixing anomalies in the Nordic Seas, causing a persistent weakening of the SPG. (orig.)

  9. Increasing water cycle extremes in California and in relation to ENSO cycle under global warming

    Science.gov (United States)

    Yoon, Jin-Ho; Wang, S-Y Simon; Gillies, Robert R.; Kravitz, Ben; Hipps, Lawrence; Rasch, Philip J.

    2015-01-01

    Since the winter of 2013–2014, California has experienced its most severe drought in recorded history, causing statewide water stress, severe economic loss and an extraordinary increase in wildfires. Identifying the effects of global warming on regional water cycle extremes, such as the ongoing drought in California, remains a challenge. Here we analyse large-ensemble and multi-model simulations that project the future of water cycle extremes in California as well as to understand those associations that pertain to changing climate oscillations under global warming. Both intense drought and excessive flooding are projected to increase by at least 50% towards the end of the twenty-first century; this projected increase in water cycle extremes is associated with a strengthened relation to El Niño and the Southern Oscillation (ENSO)—in particular, extreme El Niño and La Niña events that modulate California's climate not only through its warm and cold phases but also its precursor patterns. PMID:26487088

  10. Sources and pathways of 90Sr in the North Atlantic-Arctic region: present day and global warming

    International Nuclear Information System (INIS)

    Gao Yongqi; Drange, Helge; Johannessen, Ola M.; Pettersson, Lasse H.

    2009-01-01

    The spatial and temporal distributions of the anthropogenic radionuclides 137 Cs and 90 Sr, originating from nuclear bomb testing, the Sellafield reprocessing plant in the Irish Sea (UK), and from the Ob and Yenisey river discharges to the Arctic Ocean, have been simulated using the global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The physical model is forced with daily atmospheric re-analysis fields for the period of 1948-1999. Comparison of the temporal evolution of the observed and the simulated concentrations of 90 Sr has been performed in the Kara Sea. The relative contributions of the different sources on the temporal and spatial distributions of the surface 90 Sr are quantified over the simulated period. It follows that the Ob river discharge dominated the surface 90 Sr over most of the Arctic Ocean and along the eastern and western coasts of Greenland before 1960. During the period of 1980-1990, the atmospheric fallout and the Ob river discharge were equally important for the 90 Sr distribution in the Arctic Ocean. Furthermore, an attempt has been made to explore the possible dispersion of accidental released 90 Sr from the Ob and Yenisey rivers under a global warming scenario (2 x CO 2 ). The difference between the present-day and the global warming scenario runs indicates that more of the released 90 Sr from the Ob and Yenisey rivers is confined to the Arctic Ocean in the global warming run, particularly in the near coastal, non-European part of the Arctic Ocean.

  11. Rising water temperatures, reproduction and recruitment of an invasive oyster, Crassostrea gigas, on the French Atlantic coast.

    Science.gov (United States)

    Dutertre, Mickaël; Beninger, Peter G; Barillé, Laurent; Papin, Mathias; Haure, Joël

    2010-02-01

    The recent appearance and invasion of feral oysters (Crassostrea gigas) along the northern European Atlantic coast, underscores the necessity to investigate the relationship between environmental variables, reproductive physiology, larval development and recruitment. We studied these relationships at both high (HT) and intermediate (IT) - turbidity sites, through historical data on water temperatures, multi-parameter environmental probes, histological analyses, and field collections of planktonic larvae and settled post-larvae in 2005 and 2006. A progressive warming trend was observed, especially since 1995, when oyster proliferation first became severe. Threshold temperatures for oocyte growth, larval development and settlement were achieved in both 2005 and 2006. The HT site showed greater numbers of larvae and post-larvae than the IT site for both years, with the highest numbers of post-larvae observed at both sites during the warmer summer of 2006. These results suggest that increased temperatures in northern European waters allow successful reproduction, larval development, and recruitment of C. gigas. High turbidity conditions further enhance this success. 2009 Elsevier Ltd. All rights reserved.

  12. Water mass distributions and transports for the 2014 GEOVIDE cruise in the North Atlantic

    Science.gov (United States)

    García-Ibáñez, Maribel I.; Pérez, Fiz F.; Lherminier, Pascale; Zunino, Patricia; Mercier, Herlé; Tréguer, Paul

    2018-04-01

    We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended optimum multiparameter (eOMP) analysis provides the framework for interpreting the observed distributions of trace elements and their isotopes. Central Waters and Subpolar Mode Waters (SPMW) dominated the upper part of the GEOTRACES-GA01 section. At intermediate depths, the dominant water mass was Labrador Sea Water, while the deep parts of the section were filled by Iceland-Scotland Overflow Water (ISOW) and North-East Atlantic Deep Water. We also evaluate the water mass volume transports across the 2014 OVIDE line (Portugal to Greenland section) by combining the water mass fractions resulting from the eOMP analysis with the absolute geostrophic velocity field estimated through a box inverse model. This allowed us to assess the relative contribution of each water mass to the transport across the section. Finally, we discuss the changes in the distribution and transport of water masses between the 2014 OVIDE line and the 2002-2010 mean state. At the upper and intermediate water levels, colder end-members of the water masses replaced the warmer ones in 2014 with respect to 2002-2010, in agreement with the long-term cooling of the North Atlantic Subpolar Gyre that started in the mid-2000s. Below 2000 dbar, ISOW increased its contribution in 2014 with respect to 2002-2010, with the increase being consistent with other estimates of ISOW transports along 58-59° N. We also observed an increase in SPMW in the East Greenland Irminger Current in 2014 with respect to 2002-2010, which supports the recent deep convection events in the Irminger Sea. From the assessment of the relative water mass contribution to the Atlantic Meridional Overturning Circulation (AMOC) across the OVIDE line, we conclude that the larger AMOC intensity in

  13. Water mass distributions and transports for the 2014 GEOVIDE cruise in the North Atlantic

    Directory of Open Access Journals (Sweden)

    M. I. García-Ibáñez

    2018-04-01

    Full Text Available We present the distribution of water masses along the GEOTRACES-GA01 section during the GEOVIDE cruise, which crossed the subpolar North Atlantic Ocean and the Labrador Sea in the summer of 2014. The water mass structure resulting from an extended optimum multiparameter (eOMP analysis provides the framework for interpreting the observed distributions of trace elements and their isotopes. Central Waters and Subpolar Mode Waters (SPMW dominated the upper part of the GEOTRACES-GA01 section. At intermediate depths, the dominant water mass was Labrador Sea Water, while the deep parts of the section were filled by Iceland–Scotland Overflow Water (ISOW and North-East Atlantic Deep Water. We also evaluate the water mass volume transports across the 2014 OVIDE line (Portugal to Greenland section by combining the water mass fractions resulting from the eOMP analysis with the absolute geostrophic velocity field estimated through a box inverse model. This allowed us to assess the relative contribution of each water mass to the transport across the section. Finally, we discuss the changes in the distribution and transport of water masses between the 2014 OVIDE line and the 2002–2010 mean state. At the upper and intermediate water levels, colder end-members of the water masses replaced the warmer ones in 2014 with respect to 2002–2010, in agreement with the long-term cooling of the North Atlantic Subpolar Gyre that started in the mid-2000s. Below 2000 dbar, ISOW increased its contribution in 2014 with respect to 2002–2010, with the increase being consistent with other estimates of ISOW transports along 58–59° N. We also observed an increase in SPMW in the East Greenland Irminger Current in 2014 with respect to 2002–2010, which supports the recent deep convection events in the Irminger Sea. From the assessment of the relative water mass contribution to the Atlantic Meridional Overturning Circulation (AMOC across the OVIDE line, we conclude

  14. Isotope paleoclimatology and Atlantic deep water history since 15 million years

    International Nuclear Information System (INIS)

    Blanc, P.L.

    1981-12-01

    18 O/ 16 O and 13 C/ 12 C ratios measurements in foraminiferal calcite are applied to the paleoclimatology of the North Atlantic and to the reconstruction of deep water exchanges between the Atlantic and Pacific Oceans, from middle miocene time (15 m.y. ago) to the present, on samples from 2 DSDP wells. Chapters 1 to 4 describe the structural frame and hydrological setting of these sites, and the stratigraphy of the deposits. A .4 m.y. lag between the initiation of the first boreal ice-caps and their extension to northern Europe is explained by the persistency of the North-Atlantic Drift. In chapters 5 to 8, the 13 C/ 12 C ratio of dissolved mineral carbon is used as a tracer of the residence time of the deep waters, the indications of which are preserved in benthonic foraminiferal calcite. It is shown that present-day type thermo-haline circulation was initiated 13.2 m.y. ago in the northern Atlantic, when the volcanic Scotland-Iceland-Greenland ridge subsided; that the closure of the Mediterranean sea during the Messinian (6.2 to 5 m.y. ago) caused this circulation to stop, and that the present circulation started again when the Mediterranean re-opened, at the beginning of the Pliocene [fr

  15. Present and past Gulf Stream variability in a cold-water coral area off Cape Lookout, West Atlantic

    Science.gov (United States)

    Mienis, F.; Pedersen, A.; Duineveld, G.; Seidenkrantz, M.; Fischel, A.; Matos, L.; Bane, J. M.; Frank, N.; Hebbeln, D.; Ross, S.

    2012-12-01

    point at Gulfstream water moving over the deployment site as was confirmed by satellite images. The instantaneous increases in of the turbidity at the onset of warm events when the current speed increases, likely represent local erosion of the seafloor and of the coral mounds. Based on the foraminifera data three zones could be observed in the piston core (13000-10000 years, 10000-7200 years and 7200-4700 years. All zones show the gradual onshore movement of the Gulf Stream, which can be related to a rapid rise in sea-level after the last deglaciation. This movement has gradually widened the band of the Gulfstream thereby compressing the surface and deeper water masses. Current speed in the area are generally strong but weakened during periods of fresh water outflow in the North Atlantic, which weakened the thermohaline circulation. This was especially clear in zone 2 around 8200 years, due to a melt water pulse of lake Agassiz and Ojibway. Data presented here show that the Gulf Stream influenced cold-water coral growth and mound formation at the SE Us margin at present as well as in the past.

  16. TOPEX/El Nino Watch - El Nino Warm Water Pool Decreasing, Jan, 08, 1998

    Science.gov (United States)

    1998-01-01

    This image of the Pacific Ocean was produced using sea surface height measurements taken by the U.S.-French TOPEX/Poseidon satellite. The image shows sea surface height relative to normal ocean conditions on Jan. 8, 1998, and sea surface height is an indicator of the heat content of the ocean. The volume of the warm water pool related to the El Nino has decreased by about 40 percent since its maximum in early November, but the area of the warm water pool is still about one and a half times the size of the continental United States. The volume measurements are computed as the sum of all the sea surface height changes as compared to normal ocean conditions. In addition, the maximum water temperature in the eastern tropical Pacific, as measured by the National Oceanic and Atmospheric Administration (NOAA), is still higher than normal. Until these high temperatures diminish, the El Nino warm water pool still has great potential to disrupt global weather because the high water temperatures directly influence the atmosphere. Oceanographers believe the recent decrease in the size of the warm water pool is a normal part of El Nino's natural rhythm. TOPEX/Poseidon has been tracking these fluctuations of the El Nino warm pool since it began in early 1997. These sea surface height measurements have provided scientists with their first detailed view of how El Nino's warm pool behaves because the TOPEX/Poseidon satellite measures the changing sea surface height with unprecedented precision. In this image, the white and red areas indicate unusual patterns of heat storage; in the white areas, the sea surface is between 14 and 32 centimeters (6 to 13 inches) above normal; in the red areas, it's about 10 centimeters (4 inches) above normal. The green areas indicate normal conditions, while purple (the western Pacific) means at least 18 centimeters (7 inches) below normal sea level.The El Nino phenomenon is thought to be triggered when the steady westward blowing trade winds weaken

  17. FINAL REPORT WIND POWER WARM SPRINGS RESERVATION TRIBAL LANDS DOE GRANT NUMBER DE-FG36-07GO17077 SUBMITTED BY WARM SPRINGS POWER & WATER ENTERPRISES A CORPORATE ENTITY OF THE CONFEDERATED TRIBES OF WARM SPRINGS WARM SPRINGS, OREGON

    Energy Technology Data Exchange (ETDEWEB)

    Jim Manion; Michael Lofting; Wil Sando; Emily Leslie; Randy Goff

    2009-03-30

    Wind Generation Feasibility Warm Springs Power and Water Enterprises (WSPWE) is a corporate entity owned by the Confederated Tribes of the Warm Springs Reservation, located in central Oregon. The organization is responsible for managing electrical power generation facilities on tribal lands and, as part of its charter, has the responsibility to evaluate and develop renewable energy resources for the Confederated Tribes of Warm Springs. WSPWE recently completed a multi-year-year wind resource assessment of tribal lands, beginning with the installation of wind monitoring towers on the Mutton Mountains site in 2003, and collection of on-site wind data is ongoing. The study identified the Mutton Mountain site on the northeastern edge of the reservation as a site with sufficient wind resources to support a commercial power project estimated to generate over 226,000 MWh per year. Initial estimates indicate that the first phase of the project would be approximately 79.5 MW of installed capacity. This Phase 2 study expands and builds on the previously conducted Phase 1 Wind Resource Assessment, dated June 30, 2007. In order to fully assess the economic benefits that may accrue to the Tribes through wind energy development at Mutton Mountain, a planning-level opinion of probable cost was performed to define the costs associated with key design and construction aspects of the proposed project. This report defines the Mutton Mountain project costs and economics in sufficient detail to allow the Tribes to either build the project themselves or contract with a developer under the most favorable terms possible for the Tribes.

  18. Benefit of warm water immersion on biventricular function in patients with chronic heart failure

    Directory of Open Access Journals (Sweden)

    Kardassis Dimitris

    2009-07-01

    Full Text Available Abstract Background Regular physical activity and exercise are well-known cardiovascular protective factors. Many elderly patients with heart failure find it difficult to exercise on land, and hydrotherapy (training in warm water could be a more appropriate form of exercise for such patients. However, concerns have been raised about its safety. The aim of this study was to investigate, with echocardiography and Doppler, the acute effect of warm water immersion (WWI and effect of 8 weeks of hydrotherapy on biventricular function, volumes and systemic vascular resistance. A secondary aim was to observe the effect of hydrotherapy on brain natriuretic peptide (BNP. Methods Eighteen patients [age 69 ± 8 years, left ventricular ejection fraction 31 ± 9%, peakVO2 14.6 ± 4.5 mL/kg/min] were examined with echocardiography on land and in warm water (34°C. Twelve of these patients completed 8 weeks of control period followed by 8 weeks of hydrotherapy twice weekly. Results During acute WWI, cardiac output increased from 3.1 ± 0.8 to 4.2 ± 0.9 L/min, LV tissue velocity time integral from 1.2 ± 0.4 to 1.7 ± 0.5 cm and right ventricular tissue velocity time integral from 1.6 ± 0.6 to 2.5 ± 0.8 cm (land vs WWI, p There was no change in the cardiovascular response or BNP after 8 weeks of hydrotherapy. Conclusion Hydrotherapy was well tolerated by all patients. The main observed cardiac effect during acute WWI was a reduction in heart rate, which, together with a decrease in afterload, resulted in increases in systolic and diastolic biventricular function. Although 8 weeks of hydrotherapy did not improve cardiac function, our data support the concept that exercise in warm water is an acceptable regime for patients with heart failure.

  19. Role of Stratospheric Water Vapor in Global Warming from GCM Simulations Constrained by MLS Observation

    Science.gov (United States)

    Wang, Y.; Stek, P. C.; Su, H.; Jiang, J. H.; Livesey, N. J.; Santee, M. L.

    2014-12-01

    Over the past century, global average surface temperature has warmed by about 0.16°C/decade, largely due to anthropogenic increases in well-mixed greenhouse gases. However, the trend in global surface temperatures has been nearly flat since 2000, raising a question regarding the exploration of the drivers of climate change. Water vapor is a strong greenhouse gas in the atmosphere. Previous studies suggested that the sudden decrease of stratospheric water vapor (SWV) around 2000 may have contributed to the stall of global warming. Since 2004, the SWV observed by Microwave Limb Sounder (MLS) on Aura satellite has shown a slow recovery. The role of recent SWV variations in global warming has not been quantified. We employ a coupled atmosphere-ocean climate model, the NCAR CESM, to address this issue. It is found that the CESM underestimates the stratospheric water vapor by about 1 ppmv due to limited representations of the stratospheric dynamic and chemical processes important for water vapor variabilities. By nudging the modeled SWV to the MLS observation, we find that increasing SWV by 1 ppmv produces a robust surface warming about 0.2°C in global-mean when the model reaches equilibrium. Conversely, the sudden drop of SWV from 2000 to 2004 would cause a surface cooling about -0.08°C in global-mean. On the other hand, imposing the observed linear trend of SWV based on the 10-year observation of MLS in the CESM yields a rather slow surface warming, about 0.04°C/decade. Our model experiments suggest that SWV contributes positively to the global surface temperature variation, although it may not be the dominant factor that drives the recent global warming hiatus. Additional sensitivity experiments show that the impact of SWV on surface climate is mostly governed by the SWV amount at 100 hPa in the tropics. Furthermore, the atmospheric model simulations driven by observed sea surface temperature (SST) show that the inter-annual variation of SWV follows that of SST

  20. Temperature profile and water depth data collected from HARRIOT LANE in the NW Atlantic (limit-40 W) from 20 February 1987 to 22 February 1987 (NODC Accession 8700096)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the HARRIOT LANE in the Northwest Atlantic Ocean and TOGA Area - Atlantic Ocean. Data...

  1. Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters.

    Directory of Open Access Journals (Sweden)

    Autumn Oczkowski

    Full Text Available Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. A recent survey and synthesis of data from four locations in Southern Rhode Island has led us to hypothesize that this warming may be amplified in the shallow (<1 m, nearshore portions of these estuaries. While intertidal areas are not typically selected as locations for long-term monitoring, we compiled data from published literature, theses, and reports that suggest that enhanced warming may be occurring, perhaps at rates three times higher than deeper estuarine waters. Warmer spring waters may be one of the factors influencing biota residing in intertidal regions both in general as well as at our specific sites. We observed greater abundance of fish, and size of Menidia sp., in recent (2010-2012 seine surveys compared to similar collections in 1962. While any linkages are speculative and data are preliminary, taken together they suggest that shallow intertidal portions of estuaries may be important places to look for the effects of climate change.

  2. Preliminary Evidence for the Amplification of Global Warming in Shallow, Intertidal Estuarine Waters.

    Science.gov (United States)

    Oczkowski, Autumn; McKinney, Richard; Ayvazian, Suzanne; Hanson, Alana; Wigand, Cathleen; Markham, Erin

    2015-01-01

    Over the past 50 years, mean annual water temperature in northeastern U.S. estuaries has increased by approximately 1.2°C, with most of the warming recorded in the winter and early spring. A recent survey and synthesis of data from four locations in Southern Rhode Island has led us to hypothesize that this warming may be amplified in the shallow (<1 m), nearshore portions of these estuaries. While intertidal areas are not typically selected as locations for long-term monitoring, we compiled data from published literature, theses, and reports that suggest that enhanced warming may be occurring, perhaps at rates three times higher than deeper estuarine waters. Warmer spring waters may be one of the factors influencing biota residing in intertidal regions both in general as well as at our specific sites. We observed greater abundance of fish, and size of Menidia sp., in recent (2010-2012) seine surveys compared to similar collections in 1962. While any linkages are speculative and data are preliminary, taken together they suggest that shallow intertidal portions of estuaries may be important places to look for the effects of climate change.

  3. TOPEX/El Nino Watch - Warm Water Pool is Increasing, Nov. 10, 1997

    Science.gov (United States)

    1997-01-01

    This image of the Pacific Ocean was produced using sea surface height measurements taken by the U.S./French TOPEX/Poseidon satellite. The image shows sea surface height relative to normal ocean conditions on Nov. 10, 1997. The volume of extra warm surface water (shown in white) in the core of the El Nino continues to increase, especially in the area between 15 degrees south latitude and 15 degrees north latitude in the eastern Pacific Ocean. The area of low sea level (shown in purple) has decreased somewhat from late October. The white and red areas indicate unusual patterns of heat storage; in the white areas, the sea surface is between 14 centimeters and 32 cm (6 inches to 13 inches) above normal; in the red areas, it is about 10 centimeters (4 inches) above normal. The surface area covered by the warm water mass is about one-and-one-half times the size of the continental United States. The added amount of oceanic warm water near the Americas, with a temperature between 21 to 30 degrees Celsius (70 to 85 degrees Fahrenheit), is about 30 times the volume of water in all the U.S. Great Lakes combined. The green areas indicate normal conditions, while purple (the western Pacific) means at least 18 centimeters (7 inches) below normal sea level.The El Nino phenomenon is thought to be triggered when the steady westward blowing trade winds weaken and even reverse direction. This change in the winds allows a large mass of warm water (the red and white areas) that is normally located near Australia to move eastward along the equator until it reaches the coast of South America. The displacement of so much warm water affects evaporation, where rain clouds form and, consequently, alters the typical atmospheric jet stream patterns around the world. Using these global data, limited regional measurements from buoys and ships, and a forecasting model of the ocean-atmospheric system, the National Centers for Environmental Prediction (NCEP) of the National Oceanic and Atmospheric

  4. Fingerprinting North Atlantic water masses near Iceland using Nd-isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Frank, Norbert [Institut fuer Umweltphysik, INF229, Heidelberg (Germany); Waldner, Astrid [Paul Scherrer Institute, Villigen (Switzerland); Montagna, Paolo [CNR - ISMAR, Bologna (Italy); Colin, Christophe [IDES, Universite de Paris-Sud, Orsay (France); Wu, Qiong [State Key Laboratory, Tongji University, Shanghai (China)

    2015-07-01

    The radiogenic {sup 143}Nd/{sup 144}Nd ratio of seawater is a valuable tracer of north Atlantic circulation pathways, driven by continental runoff (freshwater and Aeolian dust), boundary exchange and advection and thus mixing patterns. A region of particular interest in the North Atlantic is the overflow across the Iceland-Scotland Ridge injecting water from the Arctic Ocean into the Iceland basin (Iceland Scotland Overflow Water). However, Iceland itself constitutes a local source for Nd due to possible leaching of young volcanic basalts adding radiogenic {sup 143}Nd/{sup 144}Nd to seawater. We have conducted an intense survey of physical properties and Nd-isotope composition between Iceland and the Azores that allows to fingerprint different water masses of the North Atlantic through the {sup 143}Nd/{sup 144}Nd ratio and that demonstrates the very local influence of volcanic material to the seawater Nd cycle. A first local transect is achieved from the open ocean to the outflow of the Vatnajoekull glacier. Runoff influences seawater Nd in close vicinity (< 40 km near the outflow). A along shelf transect provide a similar observation. From Iceland to the Azores, however, water masses of the sub-tropical and sub-polar gyre are clearly distinguishable.

  5. Tropical Cyclone Exposure for U.S. waters within the North Atlantic Ocean basin, 1900-2013

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent modeled, historical exposure of U.S. offshore and coastal waters to tropical cyclone activity within the North Atlantic Ocean basin. BOEM Outer...

  6. Influences of North Atlantic Oscillation (NAO) on warm season temperature and crop yields in the southwestern US

    Science.gov (United States)

    Myoung, B.; Kim, S.; Kim, J.; Kafatos, M.

    2013-12-01

    Despite advancements in agricultural technology, agricultural productivity remains vulnerable to extreme meteorological conditions. This study has found significant impacts of North Atlantic Oscillation (NAO) on extreme temperatures and in turn on crop yields in the Southwestern United States (SW US) region. Analyses of multi-year data of observed temperatures and simulated maize yields reveal that NAO affects positively the daily temperature maxima and minima in the green-up periods (March-June) and that the response of maize yields to NAO varies according to the climatological mean temperatures. In warmer regions, a combination of above-normal NAO in the planting periods and below-normal NAO in the growing periods is favorable for high maize yields by reducing extremely cold days during the planting periods and extremely hot days in the later periods, respectively. In colder regions, continuously above-normal NAO conditions favor higher yields via above normal thermal conditions. Results in this study suggest that NAO predictions can benefit agricultural planning in SW US.

  7. Is Detrusor Contraction during Rapid Bladder Filling Caused by Cold or Warm Water? A Randomized, Controlled, Double-Blind Trial.

    Science.gov (United States)

    Kozomara, Marko; Mehnert, Ulrich; Seifert, Burkhardt; Kessler, Thomas M

    2018-01-01

    We investigated whether detrusor contraction during rapid bladder filling is provoked by cold or warm water. Patients with neurogenic lower urinary tract dysfunction were included in this randomized, controlled, double-blind trial. At the end of a standard urodynamic investigation patients underwent 2 bladder fillings using a 4C ice water test or a 36C warm water test saline solution at a filling speed of 100 ml per minute. The order was randomly selected, and patients and investigators were blinded to the order. The primary outcome measure was detrusor overactivity, maximum detrusor pressure and maximum bladder filling volume during the ice and warm water tests. Nine women and 31 men were the subject of data analysis. Neurogenic lower urinary tract dysfunction was caused by spinal cord injury in 33 patients and by another neurological disorder in 7. Irrespective of test order detrusor overactivity occurred significantly more often during the ice water test than during the warm water test (30 of 40 patients or 75% vs 25 of 40 or 63%, p = 0.02). When comparing the ice water test to the warm water test, maximum detrusor pressure was significantly higher and maximum bladder filling volume was significantly lower during the ice water test (each p warm water first) had no effect on the parameters. Our findings imply that the more frequent detrusor overactivity, higher maximum detrusor pressure and lower bladder filling volume during the ice water test compared to the warm water test were caused by cold water. This underlies the theory of a C-fiber mediated bladder cooling reflex in humans. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  8. Wintertime re-ventilation of the East Greenland Current's Atlantic-origin Overflow Water in the western Iceland Sea

    Science.gov (United States)

    Våge, Kjetil; Håvik, Lisbeth; Papritz, Lukas; Spall, Michael; Moore, Kent

    2017-04-01

    The Deep Western Boundary Current constitutes the lower limb of the Atlantic Meridional Overturning Circulation, and, as such, is a crucial component of the Earth's climate system. The largest and densest contribution to the current stems from the overflow plume that passes through Denmark Strait. A main source of Denmark Strait Overflow Water (DSOW) is the East Greenland Current (EGC). The DSOW transported by the EGC originates from the Atlantic inflow into the Nordic Seas. This is then transformed into Atlantic-origin Overflow Water while progressing northward through the eastern part of the Nordic Seas. Here we show, using measurements from autonomous gliders deployed from fall 2015 to spring 2016, that the Atlantic-origin Overflow Water transported toward Denmark Strait by the EGC was re-ventilated while transiting the western Iceland Sea in winter. In summer, this region is characterized by an upper layer of cold, fresh Polar Surface Water that is thought to prevent convection. But in fall and winter this fresh water mass is diverted toward the Greenland shelf by enhanced northerly winds, which results in a water column that is preconditioned for convection. Severe heat loss from the ocean to the atmosphere offshore of the ice edge subsequently causes the formation of deep mixed layers. This further transforms the Atlantic-origin Overflow Water and impacts the properties of the DSOW, and hence the deepest and densest component of the lower limb of the Atlantic Meridional Overturning Circulation.

  9. Parasites as biological tags for stock identification of blackspot seabream, Pagellus bogaraveo, in Portuguese northeast Atlantic waters

    Directory of Open Access Journals (Sweden)

    Margarida Hermida

    2013-10-01

    Full Text Available In this study the following parasites were selected as biological tags for the identification of blackspot seabream (Pagellus bogaraveo stocks in the northeast Atlantic: Diphterostomum vividum (Digenea: Zoogonidae, Anisakis simplex s.l., A. physeteris, Anisakis sp. PB-2010 (Nematoda: Anisakidae, and Bolbosoma sp. (Acanthocephala: Polymorphidae. These parasite species point to the existence of three blackspot seabream stocks in the northeast Atlantic: one in the Azores region (ICES Area X, one in continental Portuguese shelf/slope waters (ICES Area IXa, and one in the waters around Madeira (sub-area 1.2 of FAO 34, central-eastern Atlantic.

  10. Freshening of Antarctic Intermediate Water in the South Atlantic Ocean in 2005–2014

    OpenAIRE

    Yao, Wenjun; Shi, Jiuxin

    2016-01-01

    Basin-scaled freshening of Antarctic Intermediate Water (AAIW) is reported to have dominated South Atlantic Ocean during period from 2005 to 2014, as shown by the gridded monthly means Argo (Array for Real-time Geostrophic Oceanography) data. The relevant investigation was also revealed by two transatlantic occupations of repeated section along 30° S, from World Ocean Circulation Experiment Hydrographic Program. Freshening of the AAIW was compensated by the opposing salinity increase o...

  11. Freshening of Antarctic Intermediate Water in the South Atlantic Ocean in 2005–2014

    OpenAIRE

    W. Yao; J. Shi; X. Zhao

    2017-01-01

    Basin-scale freshening of Antarctic Intermediate Water (AAIW) is reported to have occurred in the South Atlantic Ocean during the period from 2005 to 2014, as shown by the gridded monthly means of the Array for Real-time Geostrophic Oceanography (Argo) data. This phenomenon was also revealed by two repeated transects along a section at 30° S, performed during the World Ocean Circulation Experiment Hydrographic Program. Freshening of the AAIW was compensated for by a salinity...

  12. New records for the shallow-water chiton fauna (Mollusca, Polyplacophora of the Azores (NE Atlantic

    Directory of Open Access Journals (Sweden)

    Sérgio Ávila

    2013-06-01

    Full Text Available Published records, original data from recent field work on all of the islands of the Azores (NE Atlantic, and a revision of the entire mollusc collection deposited in the Department of Biology of the University of the Azores (DBUA were used to compile a checklist of the shallow-water Polyplacophora of the Azores. Lepidochitona cf. canariensis and Tonicella rubra are reported for the first time for this archipelago, increasing the recorded Azorean fauna to seven species.

  13. Evidence of Atlantic salmon Salmo salar fry movement between fresh water and a brackish environment.

    Science.gov (United States)

    Taal, I; Rohtla, M; Saks, L; Svirgsden, R; Kesler, M; Matetski, L; Vetemaa, M

    2017-08-01

    This study reports descent of Atlantic salmon Salmo salar fry from their natal streams to brackish waters of the Baltic Sea and their use of this environment as an alternative rearing habitat before ascending back to freshwater streams. To the authors' knowledge, residency in a brackish environment has not previously been demonstrated in S. salar fry. Recruitment success and evolutionary significance of this alternative life-history strategy are presently not known. © 2017 The Fisheries Society of the British Isles.

  14. Warm Water Compress as an Alternative for Decreasing the Degree of Phlebitis.

    Science.gov (United States)

    Annisa, Fitri; Nurhaeni, Nani; Wanda, Dessie

    Intravenous fluid therapy is an invasive procedure which may increase the risk of patient complications. One of the most common of these is phlebitis, which may cause discomfort and tissue damage. Therefore, a nursing intervention is needed to effectively treat phlebitis. The purpose of this study was to investigate the effectiveness of applying a warm compression intervention to reduce the degree of phlebitis. A quasi-experimental pre-test and post-test design was used, with a non-equivalent control group. The total sample size was 32 patients with degrees of phlebitis ranging from 1 to 4. The total sample was divided into 2 interventional groups: those patients that were given 0.9% NaCl compresses and those given warm water compresses. The results showed that both compresses were effective in reducing the degree of phlebitis, with similar p values (p = .000). However, there was no difference in the average reduction score between the two groups (p = .18). Therefore, a warm water compress is valuable in the treatment of phlebitis, and could decrease the degree of phlebitis both effectively and inexpensively.

  15. Response of bean cultures' water use efficiency against climate warming in semiarid regions of China.

    Science.gov (United States)

    Guoju, Xiao; Fengju, Zhang; Juying, Huang; Chengke, Luo; Jing, Wang; Fei, Ma; Yubi, Yao; Runyuan, Wang; Zhengji, Qiu

    2016-07-31

    Farm crop growing and high efficiency water resource utilizing are directly influenced by global warming, and a new challenge will be given to food and water resource security. A simulation experiment by farm warming with infrared ray radiator was carried out, and the result showed photosynthesis of broad bean was significantly faster than transpiration during the seedling stage, ramifying stage, budding stage, blooming stage and podding stage when the temperate was increased by 0.5-1.5 °C. But broad bean transpiration was faster than photosynthesis during the budding stage, blooming stage and podding stage when the temperature was increased by 1.5 °C above. The number of grain per hill and hundred-grain weight were significantly increased when the temperature was increased by 0.5-1.0 °C. But they significantly dropped and finally the yield decreased when the temperature was increased by 1.0 °C above. The broad bean yield decreased by 39.2-88.4% when the temperature was increased by 1.5-2.0 °C. The broad bean water use efficiency increased and then decreased with temperature rising. The water use efficiency increased when the temperature was increased by 1.0 °C below, and it quickly decreased when the temperature was increased by 1.0 °C above. In all, global warming in the future will significantly influence the growth, yield and water use efficiency of bean cultures in China's semiarid regions.

  16. Hiatus in global warming - example of water temperature of the Danube River at Bogojevo gauge (Serbia

    Directory of Open Access Journals (Sweden)

    Ducić Vladan

    2015-01-01

    Full Text Available The research included trends in water temperature of the Danube River at Bogojevo gauge and surface air temperature at the nearby meteorological station Sombor, as well as an analysis of the results obtained in relation to the claims of the existence of the hiatus in global air temperature increase in the period 1998-2012. In the period 1961-2013, there was a statistically significant increase in the mean annual water temperature (0.039°C/year, as well as all the average monthly values. However, with annual values for the period 1998-2013, there was a decrease. The longest periods of negative trend (27 years were recorded for January and February. A high correlation was found between the surface air temperature and water temperature for all monthly and seasonal values. In the mean annual air temperature the presence of the hiatus is not observed, but a negative trend is recorded in March (32 years, December (43 years and February (49 years. The highest correlations between water temperature and North Atlantic Oscillation (NAO, Arctic Oscillation (AO and Atlantic Multidecadal Oscillation (AMO were obtained for the NAO in January (0.60, the AMO in autumn (0.52 and the NAO in winter (0.51. For surface air temperature, the highest correlations were registered for the AMO in summer (0.49 and the NAO in winter (0.42. The results indicate the dominant role of natural factors in the decrease of winter air temperature and water temperature of the Danube. [Projekat Ministarstva nauke Republike Srbije, br. III47007

  17. Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water

    NARCIS (Netherlands)

    Frank, A.H.; Garcia, J.A.L.; Herndl, G.; Reinthaler, T.

    2016-01-01

    To decipher the influence of depth stratification andsurface provincialism on the dark ocean prokaryoticcommunity composition, we sampled the major deepwatermasses in the eastern North Atlantic coveringthree biogeographic provinces. Their diversity wasevaluated using ordination and canonical

  18. Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters.

    Directory of Open Access Journals (Sweden)

    Timothy B Grabowski

    Full Text Available The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15-16 April 2009. We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON, as well as a remotely operated underwater vehicle (ROV. A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1-5 m into the water column from the bottom at an average vertical swimming speed of 0.20-0.25 m s(-1 and maintained an average spacing of 1.0-1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

  19. Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters

    Science.gov (United States)

    Grabowski, Timothy B.; Boswell, Kevin M.; McAdam, Bruce J.; Wells, R. J. David; Marteinsdóttir, Gudrún

    2012-01-01

    The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15–16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1–5 m into the water column from the bottom at an average vertical swimming speed of 0.20–0.25 m s−1 and maintained an average spacing of 1.0–1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

  20. Assessing the viability of microorganisms in the ballast water of vessels transiting the North Atlantic Ocean.

    Science.gov (United States)

    Steichen, Jamie L; Quigg, Antonietta

    2015-12-15

    Testing phytoplankton viability within ballast tanks and receiving waters of ballast water discharge remain understudied. Potentially harmful dinoflagellates and diatoms are transported via ballast water to Galveston Bay, Texas (USA), home to three major ports: Houston, Texas City and Galveston. Ballast water from vessels transiting the North Atlantic Ocean was inoculated into treatments representing low and high salinity conditions similar to the Ports of Houston and Galveston respectively. Phytoplankton in ballast water growout experiments were deemed viable and showed growth in low and mid salinities with nutrient enrichment. Molecular methods identified several genera: Dinophysis, Gymnodinium, Gyrodinium, Heterocapsa, Peridinium, Scrippsiella, Chaetoceros and Nitzschia. These phytoplankton genera were previously identified in Galveston Bay except Scrippsiella. Phytoplankton, including those capable of forming harmful algal blooms leading to fish and shellfish kills, are transported to Galveston Bay via ballast water, and are viable when introduced to similar salinity conditions found in Galveston Bay ports. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water stability in an annual grassland

    Energy Technology Data Exchange (ETDEWEB)

    Rillig, M.C.; Wright, S.F.; Shaw, M.R.; Field, C.B.

    2002-04-01

    Despite the importance of arbuscular mycorrhizae to the functioning of terrestrial ecosystems (e.g. nutrient uptake, soil aggregation), and the increasing evidence of global warming, responses of arbuscular mycorrhizal fungi (AMF) to climate warming are poorly understood. In a field experiment using infrared heaters, we found effects of warming on AMF after one growing season in an annual grassland, in the absence of any effects on measured root parameters (weight, length, average diameter). AMF soil hyphal length was increased by over 40% in the warmed plots, accompanied by a strong trend for AMF root colonization increase. In the following year, root weight was again not significantly changed, and AMF root colonization increased significantly in the warmed plots. Concentration of the soil protein glomalin, a glycoprotein produced by AMF hyphae with importance in soil aggregation, was decreased in the warmed plots. Soil aggregate water stability, measured for five diameter size classes, was also decreased significantly. In the following year, soil aggregate weight in two size classes was decreased significantly, but the effect size was very small. These results indicate that ecosystem warming may have stimulated carbon allocation to AMF. Other factors either influenced glomalin decomposition or production, hence influencing the role of these symbionts in soil aggregation. The observed small changes in soil aggregation, if widespread among terrestrial ecosystems, could have important consequences for soil carbon storage and erosion in a warmed climate, especially if there are cumulative effects of warming. (au)

  2. The annual cycle of plutonium in the water column of a warm, monomictic reservoir

    International Nuclear Information System (INIS)

    Pinder, J.E. III; Alberts, J.J.; Bowling, J.W.; Nelson, D.M.; Orlandini, K.A.

    1992-01-01

    An annual cycle occurs in the 239,240 Pu inventories of the water column of Pond B, an 87-ha warm monomictic reservoir on the US Department of Energy's Savannah River Site in Barnwell Co., South Carolina. The pond has elevated concentrations of 238 Pu and 239,240 Pu in sediments due to releases from former reactor operations and continues to receive additional Pu input from atmospheric deposition. For surface waters, the 239,240 Pu inventory increases following turnover in November to a maximum in March followed by a decline until later summer when minimum inventories occur. For deeper waters, the 239,240 Pu inventories increase rapidly following turnover and reach maximum values in March. The inventories in deeper waters remain large from March until turnover. Maximum inventories for the entire water column occur in March with minimum inventories at turnover in October and November. Turnover results in a redistribution of Pu across water depth but no measurable Pu loss from the water column. Ratios of 238 Pu: 239,240 Pu indicate that the cycle involves primarily Pu from sediment sources with little influence from atmospheric sources. Thus, the cycle represents net remobilization of 239,240 Pu from the sediments to the water column during the oxic, holomictic portion of the year followed by a net loss of Pu from the water column once stratification occurs. (author)

  3. Radium-226 and barium as tracers of water masses in the North Atlantic (GA01-GEOTRACES)

    Science.gov (United States)

    Le Roy, Emilie; Sanial, Virginie; Charette, Matthew; Henderson, Paul; Jacquet, Stéphanie; García-Ibáñez, Maribel; Pérez, Fiz; Lherminer, Pascale; Souhaut, Marc; Jeandel, Catherine; Lacan, François; van Beek, Pieter

    2017-04-01

    In this study, we report concentrations of radium-226 (226Ra, t1/2=1602 y) and barium determined along the GEOVIDE section conducted in the North Atlantic (May-July 2014; Portugal-Greenland-Canda) in the framework of the international GEOTRACES program. A high vertical resolution (up to 22 depths per station) was achieved by analyzing small volumes (˜10 L) of seawater for 226Ra using a radon emanation technique. We will present the distribution of 226Ra activities and barium concentrations in contrasting biogeochemical regions of the North Atlantic (Iberian margin, West European Basin, Reykjanes Ridge, Irminger Sea, Greenland margin and Labrador Sea). These regions strongly differ in terms of boundary inputs, biogeochemistry and deep water formation. We observe a linear correlation between 226Ra and barium along the GEOVIDE section, which results from the dominantly conservative behavior of the two tracers. However, deviations from the linear correlation between 226Ra and Ba are found in several places. The potential causes for such deviations are investigated. Optimum multi-parameter (OMP) analysis was thus used to distinguish the relative importance of physical transport (i.e., water mass mixing) from non-conservative processes (sedimentary, river or hydrothermal inputs; uptake by particles) on the 226Ra and Ba distribution in the North Atlantic.

  4. Low flows and water temperature risks to Asian coal power plants in a warming world

    Science.gov (United States)

    Wang, Y.; Byers, E.; Parkinson, S.; Wanders, N.; Wada, Y.; Bielicki, J. M.

    2017-12-01

    Thermoelectric power generation requires cooling, normally provided by wet cooling systems. The withdrawal and discharge of cooling water are subject to regulation. Therefore, operation of power plants may be vulnerable to changes in streamflow and rises in water temperatures. In Asia, about 489 GW of coal-fired power plants are currently under construction, permitted, or announced. Using a comprehensive dataset of these planned coal power plants (PCPPs) and cooling water use models, we investigated whether electricity generation at these power plants will be limited by streamflow and water temperature. Daily streamflow and water temperature time series are from the high-resolution (0.08ox0.08o) runs of the PCRGLOBWB hydrological model, driven by downscaled meteorological forcing from five global climate models. We compared three climate change scenarios (1.5oC, 2oC, and 3oC warming in global mean temperature) and three cooling system choice scenarios (freshwater once-through, freshwater cooling tower, and "business-as-usual" - where a PCPP uses the same cooling system as the nearest existing coal power plant). The potential available capacity of the PCPPs increase slightly from the 1.5oC to the 2oC and 3oC warming scenario due to increase in streamflow. The once-through cooling scenario results in virtually zero available capacity at the PCPPs. The other two cooling scenarios result in about 20% of the planned capacity being unavailable under all warming scenarios. Hotspots of the most water-limited PCPPs are in Pakistan, northwestern India, northwestern and north-central China, and northern Vietnam, where most of the PCPPs will face 30% to 90% unavailable nameplate capacity on annual average. Since coal power plants cannot operate effectively when the capacity factor falls below a minimum load level (about 20% to 50%), the actual limitation on generation capacity would be larger. In general, the PCPPs that will have the highest limitation on annual average

  5. Atlantic Coast Hindcast, Shallow-Water, Significant Wave Information.

    Science.gov (United States)

    1983-01-01

    AULICS LAB N E JENSEN JAN 83 UNCLASSIFIED W SRF 21NL mEEohhohhhmhEE EhhhEmmhhmhEEEE 1111 .0= 128 llI Ir111-1 11111.6 MICROCOPY RESOLUTION TEST CHART...six data products: 1. Geographical variation in the wave climate :, 2. Twenty-year percent occurrence tables: (Continued) DD EUnclassified SECUmTY...PAOCleWff DO& MIew0O I]1 Preface In late 1976, a study to produce a wave climate for U. S. coastal waters was initiated at the U. S. Army Engineer

  6. Growth decline linked to warming-induced water limitation in hemi-boreal forests.

    Directory of Open Access Journals (Sweden)

    Xiuchen Wu

    Full Text Available Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii, sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.

  7. Growth decline linked to warming-induced water limitation in hemi-boreal forests.

    Science.gov (United States)

    Wu, Xiuchen; Liu, Hongyan; Guo, Dali; Anenkhonov, Oleg A; Badmaeva, Natalya K; Sandanov, Denis V

    2012-01-01

    Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.

  8. Unintended consequences of regulating drinking water in rural Canadian communities: examples from Atlantic Canada.

    Science.gov (United States)

    Kot, Megan; Castleden, Heather; Gagnon, Graham A

    2011-09-01

    Studies that explore social capital and political will [corrected] in the context of safe drinking water provision in [corrected] Canada are limited. This paper presents findings from a study that examines the capacity of rural Canadian communities to attain regulatory compliance for drinking water. Interviews were conducted with water operators and managers in ten rural communities across Atlantic Canada to identify the burden of compliance arising from the implementation of, and adherence to, drinking water regulations. This research identifies the operator as being particularly burdened by regulatory compliance, often resulting in negative consequences including job stress and a strained relationship with the community they serve. Findings indicate that while regulations are vital to ensuring safe drinking water, not all communities have the resources in place to rise to the challenge of compliance. As a result, some communities are being negatively impacted by these regulations, rather than benefit from their intended positive effect. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. TOPEX/El Nino Watch - Warm Water Pool is Thinning, Feb, 5, 1998

    Science.gov (United States)

    1998-01-01

    This image of the Pacific Ocean was produced using sea surface height measurements taken by the U.S.-French TOPEX/Poseidon satellite. The image shows sea surface height relative to normal ocean conditions on Feb. 5, 1998 and sea surface height is an indicator of the heat content of the ocean. The area and volume of the El Nino warm water pool that is affecting global weather patterns remains extremely large, but the pool has thinned along the equator and near the coast of South America. This 'thinning' means that the warm water is not as deep as it was a few months ago. Oceanographers indicate this is a classic pattern, typical of a mature El Nino condition that they would expect to see during the ocean's gradual transition back to normal sea level. In this image, the white and red areas indicate unusual patterns of heat storage; in the white areas, the sea surface is between 14 and 32 centimeters (6 to 13 inches) above normal; in the red areas, it's about 10 centimeters (4 inches) above normal. The green areas indicate normal conditions, while purple (the western Pacific) means at least 18 centimeters (7 inches) below normal sea level. The El Nino phenomenon is thought to be triggered when the steady westward blowing trade winds weaken and even reverse direction. This change in the winds allows a large mass of warm water (the red and white area) that is normally located near Australia to move eastward along the equator until it reaches the coast of South America. The displacement of so much warm water affects evaporation, where rain clouds form and, consequently, alters the typical atmospheric jet stream patterns around the world. Using satellite imagery, buoy and ship data, and a forecasting model of the ocean-atmosphere system, the National Oceanic and Atmospheric Administration, (NOAA), has continued to issue an advisory indicating the so-called El Nino weather conditions that have impacted much of the United States and the world are expected to remain through

  10. Gradients in microbial methanol uptake: productive coastal upwelling waters to oligotrophic gyres in the Atlantic Ocean

    Science.gov (United States)

    Dixon, Joanna L; Sargeant, Stephanie; Nightingale, Philip D; Colin Murrell, J

    2013-01-01

    Methanol biogeochemistry and its importance as a carbon source in seawater is relatively unexplored. We report the first microbial methanol carbon assimilation rates (k) in productive coastal upwelling waters of up to 0.117±0.002 d−1 (∼10 nmol l−1 d−1). On average, coastal upwelling waters were 11 times greater than open ocean northern temperate (NT) waters, eight times greater than gyre waters and four times greater than equatorial upwelling (EU) waters; suggesting that all upwelling waters upon reaching the surface (⩽20 m), contain a microbial population that uses a relatively high amount of carbon (0.3–10 nmol l−1 d−1), derived from methanol, to support their growth. In open ocean Atlantic regions, microbial uptake of methanol into biomass was significantly lower, ranging between 0.04–0.68 nmol l−1 d−1. Microbes in the Mauritanian coastal upwelling used up to 57% of the total methanol for assimilation of the carbon into cells, compared with an average of 12% in the EU, and 1% in NT and gyre waters. Several methylotrophic bacterial species were identified from open ocean Atlantic waters using PCR amplification of mxaF encoding methanol dehydrogenase, the key enzyme in bacterial methanol oxidation. These included Methylophaga sp., Burkholderiales sp., Methylococcaceae sp., Ancylobacter aquaticus, Paracoccus denitrificans, Methylophilus methylotrophus, Methylobacterium oryzae, Hyphomicrobium sp. and Methylosulfonomonas methylovora. Statistically significant correlations for upwelling waters between methanol uptake into cells and both chlorophyll a concentrations and methanol oxidation rates suggest that remotely sensed chlorophyll a images, in these productive areas, could be used to derive total methanol biological loss rates, a useful tool for atmospheric and marine climatically active gas modellers, and air–sea exchange scientists. PMID:23178665

  11. Observed and modeled pathways of the Iceland Scotland Overflow Water in the eastern North Atlantic

    Science.gov (United States)

    Zou, Sijia; Lozier, Susan; Zenk, Walter; Bower, Amy; Johns, William

    2017-12-01

    The spreading of Iceland Scotland Overflow Water (ISOW) in the eastern North Atlantic has largely been studied in an Eulerian frame using numerical models or with observations limited to a few locations. No study to date has provided a comprehensive description of the ISOW spreading pathways from both Eulerian and Lagrangian perspectives. In this paper, we use a combination of previously unreported current meter data, hydrographic data, RAFOS float data, and a high resolution (1/12°) numerical ocean model to study the spreading pathways of ISOW from both of these perspectives. We identify three ISOW transport cores in the central Iceland Basin (∼59°N), with the major core along the eastern boundary of the Reykjanes Ridge (RR) and the other two in the basin interior. Based on trajectories of observed and/or numerical floats seeded along 59°N, we also describe the ISOW spreading pathways and quantify their relative importance. Within 10 years, 7-11% of ISOW from 59°N escapes into the Irminger Sea via gaps in the RR north of the Charlie Gibbs Fracture Zone (CGFZ); the water that moves through these gaps principally originates from the shallower ISOW layer along the RR eastern boundary. 10-13% travels further southward until the CGFZ, where it crosses westward into the western subpolar gyre. 18-21% of ISOW spreads southward along the eastern flank of the Mid-Atlantic Ridge into the Western European Basin (WEB). Most of the remaining water stays in the Iceland Basin over the 10-year period. A model-based investigation provides a first look at the temporal variability of these ISOW pathways. We find that the fraction of southward water exported into the WEB is anti-correlated with the export through the CGFZ, a result assumed to reflect these pathways' interactions with the North Atlantic Current in magnitude and/or position shift.

  12. Transport of North Pacific 137Cs labeled waters to the south-eastern Atlantic Ocean

    Science.gov (United States)

    Sanchez-Cabeza, J. A.; Levy, I.; Gastaud, J.; Eriksson, M.; Osvath, I.; Aoyama, M.; Povinec, P. P.; Komura, K.

    2011-04-01

    During the reoccupation of the WOCE transect A10 at 30°S by the BEAGLE2003 cruise, the SHOTS project partners collected a large number of samples for the analysis of isotopic tracers. 137Cs was mostly deposited on the oceans surface during the late 1950s and early 1960s, after the atmospheric detonation of large nuclear devices, which mostly occurred in the Northern Hemisphere. The development of advanced radioanalytical and counting techniques allowed to obtain, for the first time in this region, a zonal section of 137Cs water concentrations, where little information existed before, thus constituting an important benchmark for further studies. 137Cs concentrations in the upper waters (0-1000 m) of the south-eastern Atlantic Ocean are similar to those observed in the south-western Indian Ocean, suggesting transport of 137Cs labeled waters by the Agulhas current to the Benguela Current region. In contrast, bomb radiocarbon data do not show this feature, indicating the usefulness of 137Cs as a radiotracer of water mass transport from the Indian to the South Atlantic Ocean.

  13. Water environments: anthropogenic pressures and ecosystem changes in the Atlantic drainage basins of Brazil.

    Science.gov (United States)

    Marques, Marcia; da Costa, Monica F; Mayorga, Maria Irles de O; Pinheiro, Patrícia R

    2004-02-01

    Densely occupied drainage basins and coastal zones in developing countries that are facing economic growth are likely to suffer from moderate to severe environmental impacts regarding different issues. The catchment basins draining towards the Atlantic coast from northeastern to southern Brazil include a wide range of climatic zones and diverse ecosystems. Within its borders lies the Atlantic rain forest, significant extensions of semiarid thorn forests (caatinga), vast tree and scrub woodlands (cerrado) and most of the 6670 km of the Brazilian coast and its marine ecosystems. In recent decades, human activities have increasingly advanced over these natural resources. Littoralization has imposed a burden on coastal habitats and communities. Most of the native vegetation of the cerrado and caatinga was removed and only 7% of the original Atlantic rainforest still exists. Estuaries, bays and coastal lagoons have been irreversibly damaged. Land uses, damming and water diversion have become the major driving forces for habitat loss and aquatic ecosystem modification. Regardless of the contrast between the drought-affected northeastern Brazil and the much more prosperous and industrialized southeastern/southern Brazil, the impacts on habitat and communities were found equally severe in both cases. Attempts to halt environmental degradation have not been effective. Instead of focusing on natural resources separately, it is suggested that more integrated environmental policies that focus on aquatic ecosystems integrity are introduced.

  14. Warm versus Cold Water Island Tourism: A Review of Policy Implications

    Directory of Open Access Journals (Sweden)

    Godfrey Baldacchino

    2006-11-01

    Full Text Available Not sun, sea, sand but ice, isolation, indigenous people: the critical exploration of extreme tourism in cold water locations has barely started. Cold water island locations tend to have harsh, pristine and fragile natural environments, characterized by wide open spaces. They become contexts for an exceptional and expensive form of vigorous, outdoor, adventure or cultural tourism, and direct encounters with nature. The nature and practices of the tourism industry suggest a more sustainable form of island tourism, very different from what is experienced on the warm, tropical and exotic island stereotype.This paper critically reviews some of the salient contrasts between the ‘hot’ and ‘cold’ versions of island tourism. It discusses how, on many ‘cold water’ island locations, sound strategic management, limited civilian ‘buy in’, low populations and an absence of pluralism in political life, can conspire with climate and relative inaccessibility to limit tourism to a small scale, low-impact industry with a relatively high, locally-retained value added. Some ‘warm water’ islands are trying to follow this model for tourism development, with mixed results.

  15. Seawater/Saline Agriculture for Energy, Warming, Water, Rainfall, Land, Food and Minerals

    Science.gov (United States)

    Bushnell, Dennis

    2006-01-01

    The combination of the incipient demise of cheap oil and increasing evidence of Global Warming due to anthropogenic fossil carbon release has reinvigorated the need for and efforts on Renewable energy sources, especially for transportation applications. Biomass/Bio-diesel appears to have many benefits compared to Hydrogen, the only other major renewable transportation fuel candidate. Biomass Production is currently limited by available arable land and fresh water. Halophyte Plants and seawater irrigation proffer a wholly new biomass production mantra using wastelands and very plentiful seawater. Such an approach addresses many-to-most of the major emerging Societal Problems including Land, Water, Food, Warming and Energy. For many reasons, including seawater agriculture, portions of the Sahara appear to be viable candidates for future Biomass Production. The apparent nonlinearity between vegetation cover and atmospheric conditions over North Africa necessitates serious coupled boundary layer Meteorology and Global Circulation Modeling to ensure that this form of Terra Forming is Favorable and to avoid adverse Unintended Consequences.

  16. Biodiversity and biogeographic relationships of the polychaete fauna in French Atlantic and Mediterranean waters

    Directory of Open Access Journals (Sweden)

    Jean-Claude Dauvin

    2006-12-01

    Full Text Available A survey of the literature, including the recent systematic reviews, reveals that 934 polychaete species have been recorded in French Atlantic (including the English Channel and Mediterranean marine waters, including 818 species living on the continental shelf and 116 species that are strictly bathyal. These 934 species belong to 71 families, among which the Syllidae is the most diverse (97 species, followed by the Serpulidae (69 species, Spionidae and Phyllodocidae, each with more than 40 species. Forty-four families have fewer than 10 species recorded in each. The total number of species is spread over 11 continental shelf areas as well as the Atlantic and Mediterranean bathyal depths. In terms of species diversity, the richest areas are the Mediterranean coasts of Provence-Côte d’Azur (507 species and Languedoc-Roussillon (483 species, the western part of the English Channel (402 species, and the southern part of the Bay of Biscay (343 species. The lowest numbers of species were recorded in the eastern English Channel, due to an impoverishment of all the fauna in this part of the Channel. Other areas—for example, the Iroise Sea, the coast of Corsica and Mediterranean bathyal depths—also show low numbers, but this may only reflect the fact that insufficient information about these areas is available. A similarity analysis of 13 areas distinguishes four distinct faunal groups, each specific to one of four general locations: (1 the bathyal Atlantic and Mediterranean zones, including the coast of Corsica, (2 the two Mediterranean coastal areas (Provence-Côte d’Azur and Languedoc-Roussillon, (3 the four zones of the Atlantic continental shelf, and (4 the English Channel. The combined species can be separated into 17 different biogeographic groups.

  17. Distribution of Upper Circumpolar Deep Water on the warming continental shelf of the West Antarctic Peninsula

    Science.gov (United States)

    Couto, Nicole; Martinson, Douglas G.; Kohut, Josh; Schofield, Oscar

    2017-07-01

    We use autonomous underwater vehicles to characterize the spatial distribution of Upper Circumpolar Deep Water (UCDW) on the continental shelf of the West Antarctic Peninsula (WAP) and present the first near-synoptic measurements of mesoscale features (eddies) containing UCDW on the WAP. Thirty-three subsurface eddies with widths on the order of 10 km were detected during four glider deployments. Each eddy contributed an average of 5.8 × 1016 J to the subpycnocline waters, where a cross-shelf heat flux of 1.37 × 1019 J yr-1 is required to balance the diffusive loss of heat to overlying winter water and to the near-coastal waters. Approximately two-thirds of the heat coming onto the shelf diffuses across the pycnocline and one-third diffuses to the coastal waters; long-term warming of the subpycnocline waters is a small residual of this balance. Sixty percent of the profiles that contained UCDW were part of a coherent eddy. Between 20% and 53% of the lateral onshore heat flux to the WAP can be attributed to eddies entering Marguerite Trough, a feature in the southern part of the shelf which is known to be an important conduit for UCDW. A northern trough is identified as additional important location for eddy intrusion.

  18. Characteristics of the cold-water belt formed off Soya Warm Current

    Science.gov (United States)

    Ishizu, Miho; Kitade, Yujiro; Matsuyama, Masaji

    2008-12-01

    We examined the data obtained by acoustic Doppler current profiler, conductivity-temperature-depth profiler, and expendable bathythermograph observations, which were collected in the summers of 2000, 2001, and 2002, to clarify the characteristics of the cold-water belt (CWB), i.e., lower-temperature water than the surrounding water extending from the southwest coast of Sakhalin along the offshore side of Soya Warm Current (SWC) and to confirm one of the formation mechanisms of the CWB as suggested by our previous study, i.e., the upwelling due to the convergence of bottom Ekman transport off the SWC region. The CWB was observed at about 30 km off the coast, having a thickness of 14 m and a minimum temperature of 12°C at the sea surface. The CWB does not have the specific water mass, but is constituted of three representative water types off the northeast coast of Hokkaido in summer, i.e., SWC water, Fresh Surface Okhotsk Sea Water, and Okhotsk Sea Intermediate Water. In a comparison of the horizontal distributions of current and temperature, the CWB region is found to be advected to the southeast at an average of 40 ± 29% of the maximum current velocity of the SWC. The pumping speed due to the convergence of the bottom Ekman transport is estimated as (1.5-3.0) × 10-4 m s-1. We examined the mixing ratio of the CWB, and the results implied that the water mass of the CWB is advected southeastward and mixes with a water mass upwelling in a different region off SWC.

  19. Impact of restriction of the Atlantic-Mediterranean gateway on the Mediterranean Outflow Water and eastern Atlantic circulation during the Messinian

    Science.gov (United States)

    PéRez-Asensio, J. N.; Aguirre, J.; Schmiedl, G.; Civis, J.

    2012-09-01

    Messinian foraminiferal stable oxygen and carbon isotopes of the Montemayor-1 core (Guadalquivir Basin, SW Spain) have been investigated. This record is exceptional to study the Mediterranean Outflow Water (MOW) impact on the Atlantic meridional overturning circulation (AMOC) and global climate during the Messinian because the core is near the Guadalhorce Corridor, the last Betic gateway to be closed during the early Messinian. Our results allow dating accurately its closure at 6.18 Ma. Constant benthicδ18O values, high difference between benthic and planktonic δ18O, and low sedimentation rates before 6.18 Ma indicate the presence of a two-layer water column, with bottom winnowing due to an enhanced Mediterranean outflow current. The enhanced contribution of dense MOW to the North Atlantic Ocean likely fostered the formation of North Atlantic Deep Water (NADW). After 6.18 Ma, benthicδ18O values parallel that of the global glacioeustatic curve, the difference between benthic and planktonic δ18O is low, and sedimentation rates considerably increased. This indicates a good vertical mixing of the water column, interruption of the MOW, and a dominant glacioeustatic control on the isotopic signatures. According to the role of MOW in the modern Atlantic thermohaline circulation, the reduction of the MOW after the closure of the Guadalhorce Corridor might have resulted in a decreased NADW formation rate between 6.0 and 5.5 Ma weakening the AMOC and promoting northern hemisphere cooling. After the Gibraltar Strait opening, the restoration of the MOW and related salt export from the Mediterranean could have promoted an enhanced NADW formation.

  20. Increased transpiration and plant water stress in a black spruce bog exposed to whole ecosystem warming

    Science.gov (United States)

    Warren, J.; Ward, E. J.; Wullschleger, S. D.; Hanson, P. J.

    2017-12-01

    The Spruce and Peatland Responses under Changing Environments (SPRUCE) experiment (http://mnspruce.ornl.gov/) in Northern Minnesota, USA, has exposed 12.8 m diameter plots of an ombrotrophic Picea mariana-Ericaceous shrub bog to whole ecosystem warming (0, +2.25, +4.5, +6.75, +9 °C) since August 2015, and elevated CO2 treatments (ambient or +500 ppm) since June 2016. The mixed-age stand has trees up to 40 year old, and a 5-8 m tall canopy. Thermal dissipation sap flow probes were installed into dominant Picea mariana and Larix laricina trees in each of the 10 open-top chambers in fall 2015. This talk will focus on the first two years of sap flux data from the 10 treatment plots and the relationships with seasonal growth and prevailing environmental conditions. Sap flow was scaled to whole tree and plot level transpiration based on prior in situ calibrations using cut trees, establishment of a sapwood depth: tree diameter relationship, and the tree size distribution within each plot. We also assessed water potential in the trees and two dominant shrubs at the site: Rhododendron groenlandicum and Chamaedaphne calyculata. The warming treatments increased the growing season by up to 6 weeks, with sapflow beginning earlier in spring and lasting later into the fall. The deciduous Larix was the only species exhibiting substantial predawn water stress under the treatments, where water potentials reached -2.5 MPa for the warmest plots. The elevated CO2 reduced midday water stress in the Rhododendron, but not the Chamaedaphne, which could lead to shifts in shrub species composition.

  1. Oligocene sea water temperatures offshore Wilkes Land (Antarctica) indicate warm and stable glacial-interglacial variation and show no 'late Oligocene warming'

    Science.gov (United States)

    Hartman, Julian; Bijl, Peter; Peterse, Francien; Schouten, Stefan; Salabarnada, Ariadna; Bohaty, Steven; Escutia, Carlota; Brinkhuis, Henk; Sangiorgi, Francesca

    2017-04-01

    At present, warming of the waters below the Antarctic ice shelves is a major contributor to the instability of the Antarctic cryosphere. In order to get insight into future melt behavior of the Antarctic ice sheet, it is important to look at past warm periods that can serve as an analogue for the future. The Oligocene ( 34-23 Ma) is a period within the range of CO2 concentrations predicted by the latest IPCC report for the coming century and is characterized by a very dynamic Antarctic ice sheet, as suggested by benthic δ18O records from ice-distal sites. We suspect that, like today, environmental changes in the Southern Ocean are in part responsible for this dynamicity. To gain more insight into this, we have reconstructed sea water temperatures (SWT) based on Thaumarchaeotal lipids (TEX86) for the Oligocene record obtained from the ice-proximal Site U1356 (Integrated Ocean Drilling Program), offshore Wilkes Land. Part of our record shows a strong coupling between the lithology and SWT, which we attribute to glacial-interglacial variation. Our data shows that both glacial and interglacial temperatures are relatively warm throughout the Oligocene: 14°C and 18°C respectively, which is consistent with previously published estimates based on UK'37 and clumped isotopes for the early Oligocene. Our SST records show only a minor decline between 30 and 24 Ma, and thus show no evidence for a 'late Oligocene warming' as was suggested based on benthic δ18O records from low latitudes. Instead, the discrepancy between our SST trend and the δ18O trend suggests that the late-Oligocene benthic δ18O decrease is likely related to a decline in ice volume. After 24 Ma, however, glacial-interglacial temperature variation appears to increase. In particular, some large temperature drops occur, one of which can be related to the Mi-1 event and a major expansion of the Antarctic ice sheet.

  2. Distribution of cold-water corals in the Whittard Canyon, NE Atlantic Ocean

    OpenAIRE

    Morris, Kirsty J.; Tyler, Paul A.; Masson, Doug G.; Huvenne, Veerle A.I.; Rogers, Alex D.

    2013-01-01

    The deep-sea floor occupies about 60% of the surface of the planet and is covered mainly by fine sediments. Most studies of deep-sea benthic fauna therefore have concentrated on soft sediments with little sampling of hard substrata, such as rocky outcrops in submarine canyons. Here we assess the distribution and abundance of cold-water corals within the Whittard Canyon (NE Atlantic) using video footage from the ROV Isis. Abundances per 100 m of video transect were calculated and mapped using ...

  3. Similar mid-depth Atlantic water mass provenance during the Last Glacial Maximum and Heinrich Stadial 1

    Science.gov (United States)

    Howe, Jacob N. W.; Huang, Kuo-Fang; Oppo, Delia W.; Chiessi, Cristiano M.; Mulitza, Stefan; Blusztajn, Jurek; Piotrowski, Alexander M.

    2018-05-01

    The delivery of freshwater to the North Atlantic during Heinrich Stadial 1 (HS1) is thought to have fundamentally altered the operation of Atlantic meridional overturning circulation (AMOC). Although benthic foraminiferal carbon isotope records from the mid-depth Atlantic show a pronounced excursion to lower values during HS1, whether these shifts correspond to changes in water mass proportions, advection, or shifts in the carbon cycle remains unclear. Here we present new deglacial records of authigenic neodymium isotopes - a water mass tracer that is independent of the carbon cycle - from two cores in the mid-depth South Atlantic. We find no change in neodymium isotopic composition, and thus water mass proportions, between the Last Glacial Maximum (LGM) and HS1, despite large decreases in carbon isotope values at the onset of HS1 in the same cores. We suggest that the excursions of carbon isotopes to lower values were likely caused by the accumulation of respired organic matter due to slow overturning circulation, rather than to increased southern-sourced water, as typically assumed. The finding that there was little change in water mass provenance in the mid-depth South Atlantic between the LGM and HS1, despite decreased overturning, suggests that the rate of production of mid-depth southern-sourced water mass decreased in concert with decreased production of northern-sourced intermediate water at the onset of HS1. Consequently, we propose that even drastic changes in the strength of AMOC need not cause a significant change in South Atlantic mid-depth water mass proportions.

  4. Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options

    Science.gov (United States)

    Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG...

  5. 228Ra and 228Th concentrations in GEOSECS Atlantic surface waters

    International Nuclear Information System (INIS)

    Li, Y.H.; Toggweiler, J.R.; Feely, H.W.

    1980-01-01

    An average 228 Ra flux of 0.6 +- 0.1 dpm cm -2 yr -1 from continental shelf sediments can maintain the estimated total 228 Ra inventory of about 5x10 17 dpm in Atlantic surface waters. By fitting 228 Ra and potential temperature data to Munk's vertical advection-diffusion model, upwelling rates of 17 +- 10 m yr -1 and vertical eddy diffusion coefficients of 0.4 +- 0.2 cm 2 s -1 were obtained in the upper water column of the equatorial Atlantic. The downward fluxes of particulate 228 Th across the 350-m water depth are about 0.01 to 0.04 dpm cm -2 yr -1 in the Sargasso Sea and in the regions south of 12 0 N and about 0.06 to 0.11 dpm cm -2 yr -1 in the northern temperate region (excluding the Sargasso Sea). The shorter half-removal time of 228 Th in the equatorial (10 0 S to 20 0 N) and the northern region (35 0 to 65 0 N) are related to higher biological productivity there. (author)

  6. Ocean array alters view of Atlantic conveyor

    Science.gov (United States)

    Kornei, Katherine

    2018-02-01

    Oceanographers have put a stethoscope on the coursing circulatory system of the Atlantic Ocean, and they have found a skittish pulse that's surprisingly strong in the waters east of Greenland—discoveries that should improve climate models. The powerful currents known as the Atlantic meridional overturning circulation (AMOC) are an engine in Earth's climate. The AMOC's shallower limbs—which include the Gulf Stream—move warm water from the tropics northward, warming Western Europe. In the north, the waters cool and sink, forming deeper limbs that transport the cold water back south—and sequester anthropogenic carbon in the process. Last week, at the American Geophysical Union's Ocean Sciences meeting, scientists presented the first data from an array of instruments moored in the subpolar North Atlantic, a $35 million, seven-nation project known as the Overturning in the Subpolar North Atlantic Program (OSNAP). Since 2004, researchers have gathered data from another array, at 26°N, stretching from Florida to Africa. But OSNAP is the first to monitor the circulation farther north, where a critical aspect of the overturning occurs. The observations reveal unexpected eddies and strong variability in the AMOC currents. They also show that the currents east of Greenland contribute the most to the total AMOC flow. Climate models, on the other hand, have emphasized the currents west of Greenland in the Labrador Sea.

  7. The risk of water scarcity at different levels of global warming

    Science.gov (United States)

    Schewe, Jacob; Sharpe, Simon

    2015-04-01

    Water scarcity is a threat to human well-being and economic development in many countries today. Future climate change is expected to exacerbate the global water crisis by reducing renewable freshwater resources different world regions, many of which are already dry. Studies of future water scarcity often focus on most-likely, or highest-confidence, scenarios. However, multi-model projections of water resources reveal large uncertainty ranges, which are due to different types of processes (climate, hydrology, human) and are therefore not easy to reduce. Thus, central estimates or multi-model mean results may be insufficient to inform policy and management. Here we present an alternative, risk-based approach. We use an ensemble of multiple global climate and hydrological models to quantify the likelihood of crossing a given water scarcity threshold under different levels of global warming. This approach allows assessing the risk associated with any particular, pre-defined threshold (or magnitude of change that must be avoided), regardless of whether it lies in the center or in the tails of the uncertainty distribution. We show applications of this method on the country and river basin scale, illustrate the effects of societal processes on the resulting risk estimates, and discuss the further potential of this approach for research and stakeholder dialogue.

  8. Economical judge possibility uses solar collectors to warm service water and heating

    Directory of Open Access Journals (Sweden)

    Lívia Bodonská

    2006-09-01

    Full Text Available The sun-heated water has been used from before fossil fuels started to determine the direction of our power consumption. This article is focused on the assessing of the use of solar energy as one of inexhaustible resources that has multiple uses, including hot water service systems. Heating is rendered through solar collectors that permit to transform solar energy to warm water. We divide solar collectors into various groups but in principle they are medium temperature collectors and low temperature collectors. The work is directed also on the solar collector market. In our case the market is just at its initial stage as this technology is little known and costs of collectors are rather high, compared to our conditions, on average, they may grow up to 100,000 Slovac crowns per a family house. Because it is the only investment and the costs of operation are minimum throughout the entire collectors lifetime, from the economic point of view, it is a rather advantageous investment. Solar collectors are used in heating and also in hot service water systems in family houses, where they permit to lower costs for the consumption of many kinds of energies. In the hot service water system, solar collectors permit to lower the consumption by almost 70 %. This way of using the solar energy is very prospective and in future it will be used in various sectors

  9. Source and distribution of radon-222 and radium-226 within South Atlantic Bight waters

    International Nuclear Information System (INIS)

    Ramsey, E.

    1982-09-01

    Radon and radium concentrations were measured in South Atlantic Bight (SAB) waters during six weeks in the summer of 1981. Sampling was designed to coincide with subsurface intrusions of cold Gulf Stream water onto the continental shelf and was part of a large study of the SAB. The distinct zonation of sediment types within the SAB offered the possibility to use radon to trace advection of intruded bottom water. It was determined that the bottom excess radon concentrations, calculated from radon and radium data, were distributed into three groups. The first group of concentrations ranged from 320 to 732 dpm/100L (n=3) and was associated with water occupying the nearshore zone. The second set was sampled within intruded water in the midshelf region. These values ranged from 25.5 to 151.5 dpm/100L (n=35). The third range describes radon concentrations contained in water that is a potential source of upwelled Gulf Stream water. These shelf break concentrations ranged from -1.0 to 213.0 dpm/100L (n=13), and were found to differ significantly (P < 0.001) from the midshelf range of radon concentrations (Mann-Whitney test). The division of radon concentrations into three distinct zones within the SAB waters may provide an indicator of shelf and Gulf Stream water interactions. 55 references, 24 figures, 4 tables

  10. An Uncertainty Data Set for Passive Microwave Satellite Observations of Warm Cloud Liquid Water Path

    Science.gov (United States)

    Greenwald, Thomas J.; Bennartz, Ralf; Lebsock, Matthew; Teixeira, João.

    2018-04-01

    The first extended comprehensive data set of the retrieval uncertainties in passive microwave observations of cloud liquid water path (CLWP) for warm oceanic clouds has been created for practical use in climate applications. Four major sources of systematic errors were considered over the 9-year record of the Advanced Microwave Scanning Radiometer-EOS (AMSR-E): clear-sky bias, cloud-rain partition (CRP) bias, cloud-fraction-dependent bias, and cloud temperature bias. Errors were estimated using a unique merged AMSR-E/Moderate resolution Imaging Spectroradiometer Level 2 data set as well as observations from the Cloud-Aerosol Lidar with Orthogonal Polarization and the CloudSat Cloud Profiling Radar. To quantify the CRP bias more accurately, a new parameterization was developed to improve the inference of CLWP in warm rain. The cloud-fraction-dependent bias was found to be a combination of the CRP bias, an in-cloud bias, and an adjacent precipitation bias. Globally, the mean net bias was 0.012 kg/m2, dominated by the CRP and in-cloud biases, but with considerable regional and seasonal variation. Good qualitative agreement between a bias-corrected AMSR-E CLWP climatology and ship observations in the Northeast Pacific suggests that the bias estimates are reasonable. However, a possible underestimation of the net bias in certain conditions may be due in part to the crude method used in classifying precipitation, underscoring the need for an independent method of detecting rain in warm clouds. This study demonstrates the importance of combining visible-infrared imager data and passive microwave CLWP observations for estimating uncertainties and improving the accuracy of these observations.

  11. Contrasting trends in North Atlantic deep-water formation in the Labrador Sea and Nordic Seas during the Holocene

    NARCIS (Netherlands)

    Renssen, H.; Goosse, H.; Fichefet, T.

    2005-01-01

    The Holocene North Atlantic deep-water formation is studied in a 9,000-year long simulation with a coupled climate model of intermediate complexity, forced by changes in orbital forcing and atmospheric trace gas concentrations. During the experiment, deep-water formation in the Nordic Seas is

  12. Differentiating leucine incorporation of Archaea and Bacteria throughout the water column of the eastern Atlantic using metabolic inhibitors

    NARCIS (Netherlands)

    Yokokawa, Taichi; Sintes, Eva; de Corte, Daniele; Olbrich, Kerstin; Herndl, Gerhard J.

    2012-01-01

    The abundance (based on catalyzed reporter deposition-fluorescence in situ hybrid ization, CARD-FISH) and leucine incorporation rates of Archaea and Bacteria were determined throughout the water column in the eastern Atlantic. Bacteria dominated throughout the water column, although their

  13. Warm and Humid Air Blowing over Cold Water - Grand Banks Fog

    Science.gov (United States)

    Taylor, P.; Weng, W.

    2016-12-01

    The condensation of water vapour into droplets and the formation of fog in the Earth's atmospheric boundary layer involves a complex balance between horizontal advection and vertical turbulent mixing of heat and water vapour, cloud microphysical processes and radiative transfers of heat, plus the impact of water droplets, and sometimes ice crystals, on visibility. It is a phenomenon which has been studied for many years in a variety of contexts. On land, surface cooling of the ground via long wave radiation at night is often the trigger and a number of 1-D (height and time dependent) radiative fog models have been developed. Over the waters offshore from Newfoundland a key factor is the advection of moist air from over warm gulf stream waters to colder Labrador current water - an internal boundary-layer problem. Some basic properties can be learned from a steady state 2-D (x-z) model.The WTS (Weng, Taylor and Salmon, 2010, J. Wind Eng. Ind. Aerodyn. 98, 121-132 ) model of flow above changes in surface conditions has been used to investigate planetary boundary-layer flow over water with spatial changes in temperature, and to investigate situations leading to saturation and fog formation. Our turbulence closure includes the turbulent kinetic energy equation but we prefer to specify a height, surface roughness, Rossby number and local stability dependent, "master" length scale instead of a somewhat empirical dissipation or similar equation. Results show that fog can develop and extent to heights of order 100m in some conditions, depending on upstream profiles of wind, temperature and mixing ratio, and on solar radiation and the horizontal variations in water surface temperature.Next steps will involve validation against data being collected (by AMEC-Foster Wheeler in the Hibernia Management and Development Company Metocean project) over the Grand Banks and an interface with WRF and high resolution sea surface temperature data for forecasting fog conditions over the

  14. Natural and anthropogenic decadal pH decrease in the North Atlantic and Mediterranean Sea waters

    Science.gov (United States)

    Huertas, E.; Flecha, S.; Murata, A.; Garcia Lafuente, J.; Pérez, F. F.

    2017-12-01

    Seawater pH is undergoing a decreasing trend due to atmospheric CO2 absorption, a phenomenon known as Ocean Acidification (OA) that has been documented in different ocean regions. Certain marine basins are more vulnerable to OA, such as the Mediterranean Sea (MS), which is attributed to particular water circulation processes and biogeochemical features. Considering previous studies on OA in Mediterranean and Atlantic water masses, the main aim of this work was to identify for the first time the natural and anthropogenic contribution to decadal pH variations. Therefore, an archetypal analysis was applied to pH measurements and other biogeochemical variables collected in the Strait of Gibraltar during 10 years. Our results reveal that the biological component of the pH change in the Western Mediterranean Deep Water (WMDW) (ΔpHWMDW) represents around 56% of the total decadal pH decrease observed, highlighting the relevance of the remineralization occurring in the Alboran basin, where the WMDW resides before leaving the MS. On the other hand, neither natural nor anthropogenic forcing on the pH change in the Levantine Intermediate Water (ΔpHLIW) was detected, as pH variation was negligible. As for the North Atlantic Central Water (NACW), atmospheric CO2 uptake was responsible of 58% of the ΔpHNACW, likely related to permanent contact with the atmosphere. Additionally, estimations of the approximated ages of the NACW, LIW and WMDW in the SG of about 8, 34 and 32 years respectively have been obtained. Our results show that Mediterranean waters undergo changes in their biogeochemical characteristics during transit through the SG and gives insights on the main mechanisms affecting pH variations occurring from their formation sites to the SG.

  15. Cost analysis of ground-water supplies in the North Atlantic region, 1970

    Science.gov (United States)

    Cederstrom, Dagfin John

    1973-01-01

    The cost of municipal and industrial ground water (or, more specifically, large supplies of ground water) at the wellhead in the North Atlantic Region in 1970 generally ranged from 1.5 to 5 cents per thousand gallons. Water from crystalline rocks and shale is relatively expensive. Water from sandstone is less so. Costs of water from sands and gravels in glaciated areas and from Coastal Plain sediments range from moderate to very low. In carbonate rocks costs range from low to fairly high. The cost of ground water at the wellhead is low in areas of productive aquifers, but owing to the cost of connecting pipe, costs increase significantly in multiple-well fields. In the North Atlantic Region, development of small to moderate supplies of ground water may offer favorable cost alternatives to planners, but large supplies of ground water for delivery to one point cannot generally be developed inexpensively. Well fields in the less productive aquifers may be limited by costs to 1 or 2 million gallons a day, but in the more favorable aquifers development of several tens of millions of gallons a day may be practicable and inexpensive. Cost evaluations presented cannot be applied to any one specific well or specific site because yields of wells in any one place will depend on the local geologic and hydrologic conditions; however, with such cost adjustments as may be necessary, the methodology presented should have wide applicability. Data given show the cost of water at the wellhead based on the average yield of several wells. The cost of water delivered by a well field includes costs of connecting pipe and of wells that have the yields and spacings specified. Cost of transport of water from the well field to point of consumption and possible cost of treatment are not evaluated. In the methodology employed, costs of drilling and testing, pumping equipment, engineering for the well field, amortization at 5% percent interest, maintenance, and cost of power are considered. The

  16. The Great Warming Brian Fagan

    Science.gov (United States)

    Fagan, B. M.

    2010-12-01

    The Great Warming is a journey back to the world of a thousand years ago, to the Medieval Warm Period. Five centuries of irregular warming from 800 to 1250 had beneficial effects in Europe and the North Atlantic, but brought prolonged droughts to much of the Americas and lands affected by the South Asian monsoon. The book describes these impacts of warming on medieval European societies, as well as the Norse and the Inuit of the far north, then analyzes the impact of harsh, lengthy droughts on hunting societies in western North America and the Ancestral Pueblo farmers of Chaco Canyon, New Mexico. These peoples reacted to drought by relocating entire communities. The Maya civilization was much more vulnerable that small-scale hunter-gatherer societies and subsistence farmers in North America. Maya rulers created huge water storage facilities, but their civilization partially collapsed under the stress of repeated multiyear droughts, while the Chimu lords of coastal Peru adapted with sophisticated irrigation works. The climatic villain was prolonged, cool La Niñalike conditions in the Pacific, which caused droughts from Venezuela to East Asia, and as far west as East Africa. The Great Warming argues that the warm centuries brought savage drought to much of humanity, from China to Peru. It also argues that drought is one of the most dangerous elements in today’s humanly created global warming, often ignored by preoccupied commentators, but with the potential to cause over a billion people to starve. Finally, I use the book to discuss the issues and problems of communicating multidisciplinary science to the general public.

  17. Water vapor changes under global warming and the linkage to present-day interannual variabilities in CMIP5 models

    Science.gov (United States)

    Takahashi, Hanii; Su, Hui; Jiang, Jonathan H.

    2016-12-01

    The fractional water vapor changes under global warming across 14 Coupled Model Intercomparison Project Phase 5 simulations are analyzed. We show that the mean fractional water vapor changes under global warming in the tropical upper troposphere between 300 and 100 hPa range from 12.4 to 28.0 %/K across all models while the fractional water vapor changes are about 5-8 %/K in other regions and at lower altitudes. The "upper-tropospheric amplification" of the water vapor change is primarily driven by a larger temperature increase in the upper troposphere than in the lower troposphere per degree of surface warming. The relative contributions of atmospheric temperature and relative humidity changes to the water vapor change in each model vary between 71.5 to 131.8 % and 24.8 to -20.1 %, respectively. The inter-model differences in the water vapor change is primarily caused by differences in temperature change, except over the inter-tropical convergence zone within 10°S-10°N where the model differences due to the relative humidity change are significant. Furthermore, we find that there is generally a positive correlation between the rates of water vapor change for long-tem surface warming and those on the interannual time scales. However, the rates of water vapor change under long-term warming have a systematic offset from those on the inter-annual time scales and the dominant contributor to the differences also differs for the two time scales, suggesting caution needs to be taken when inferring long-term water vapor changes from the observed interannual variations.

  18. The Yermak Pass Branch: A Major Pathway for the Atlantic Water North of Svalbard?

    Science.gov (United States)

    Koenig, Zoé; Provost, Christine; Sennéchael, Nathalie; Garric, Gilles; Gascard, Jean-Claude

    2017-12-01

    An upward-looking Acoustic Doppler Current Profiler deployed from July 2007 to September 2008 in the Yermak Pass, north of Svalbard, gathered velocity data from 570 m up to 90 m at a location covered by sea ice 10 months out of 12. Barotropic diurnal and semidiurnal tides are the dominant signals in the velocity (more than 70% of the velocity variance). In winter, baroclinic eddies at periods between 5 and 15 days and pulses of 1-2 month periodicity are observed in the Atlantic Water layer and are associated with a shoaling of the pycnocline. Mercator-Ocean global operational model with daily and 1/12° spatial resolution is shown to have skills in representing low-frequency velocity variations (>1 month) in the West Spitsbergen Current and in the Yermak Pass. Model outputs suggest that the Yermak Pass Branch has had a robust winter pattern over the last 10 years, carrying on average 31% of the Atlantic Water volume transport of the West Spitsbergen Current (36% in autumn/winter). However, those figures have to be considered with caution as the model neither simulates tides nor fully resolves eddies and ignores residual mean currents that could be significant.

  19. Parasites as biological tags in marine fisheries research: European Atlantic waters.

    Science.gov (United States)

    Mackenzie, K; Hemmingsen, W

    2015-01-01

    Studies of the use of parasites as biological tags for stock identification and to follow migrations of marine fish, mammals and invertebrates in European Atlantic waters are critically reviewed and evaluated. The region covered includes the North, Baltic, Barents and White Seas plus Icelandic waters, but excludes the Mediterranean and Black Seas. Each fish species or ecological group of species is treated separately. More parasite tag studies have been carried out on Atlantic herring Clupea harengus than on any other species, while cod Gadus morhua have also been the subject of many studies. Other species that have been the subjects of more than one study are: blue whiting Micromesistius poutassou, whiting Merlangius merlangus, haddock Melanogrammus aeglefinus, Norway pout Trisopterus esmarkii, horse mackerel Trachurus trachurus and mackerel Scomber scombrus. Other species are dealt with under the general headings redfishes, flatfish, tunas, anadromous fish, elasmobranchs, marine mammals and invertebrates. A final section highlights how parasites can be, and have been, misused as biological tags, and how this can be avoided. It also reviews recent developments in methodology and parasite genetics, considers the potential effects of climate change on the distributions of both hosts and parasites, and suggests host-parasite systems that should reward further research.

  20. Uranium Series Radionuclides in the Water Column of the Northeast Atlantic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, F. P. [Nuclear and Technological Institute, Department of Radiological Protection and Nuclear Safety, Sacavem (Portugal)

    2013-07-15

    Naturally occurring radionuclides, namely {sup 238}U, {sup 234}U, {sup 230}Th, {sup 226}Ra, {sup 210}Pb, {sup 210}Po and {sup 232}Th, were analysed in water samples from ocean vertical profiles in three major abyssal basins of the NE Atlantic (Porcupine, Iberia and Tejo Basins), from the surface to the deep sea water layer. Concentrations were determined in the dissolved and particulate phases. The profiles of uranium isotopes in the water column, mostly in dissolved phase, showed nearly homogenized concentrations with {sup 238}U averaging 37{+-}4 mBq/Land {sup 234}U/{sup 238}U activity ratios averaging 1.13{+-}0.04, while {sup 226}Ra concentrations were 2-3 times higher in the bottom than at the ocean surface. {sup 230}Th activity concentrations were four orders of magnitude lower than {sup 234}U, confirming rapid Th scavenging from solution by the particulate matter. {sup 210}Pb and {sup 210}Po activity concentrations in the soluble phase were much lower than dissolved {sup 226}Ra. Modelling the distribution of these radionuclides in the water column leads to an average residence time of dissolved {sup 210}Pb and {sup 210}Po in the upper layer of 5 a and 1 a, respectively, and 0.6 a in the particulate phase for both radionuclides. In the deep water layer, soluble {sup 210}Pb and {sup 210}Po mean residence times were 42{+-}20 a and 2 a, respectively. The calculated {sup 210}Pb deposition flux at the abyssal sea floor is comparable with the flux derived from the {sup 210}Pb-excess inventory measured in sediments, and about 100 Bq.m-2.a{sup -1}. The {sup 210}Pb atmospheric deposition flux at the ocean surface in this region was estimated at about 74 Bq.m{sup -2}a{sup -1} and the {sup 210}Pb sink in the Northeast Atlantic is discussed. (author)

  1. Formonsella pyramidosa (Haptophyta, Papposphaeraceae): A new weakly calcified coccolithophore genus from warm-water regions

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Cros, Lluïsa; Malinverno, Elisa

    2016-01-01

    A new species Formonsella pyramidosa gen. et sp. nov. is described to accommodate a widely distributed warm-water coccolithophore species that has previously been referred to as Pappomonas sp. 2. Formonsella differs from Pappomonas with respect to, in particular, the detailed structure of the rim...... on both calicate and non-calicate coccoliths. In Formonsella the rim comprises two cycles of rod-shaped elements. Although elements in the distal layer are higher at one end, giving this cycle a serrate outline, the overall appearance is very different from the Pappomonas rim which encompasses a distal...... cycle of pentagonal elements, giving the rim a very distinct toothed appearance. Inverted rectangular pyramidal structures terminate the calicate F. pyramidosa coccoliths. In non-calicate coccoliths the central area calcification comprises differently sized tile-shaped elements, mostly arranged along...

  2. Tainting by short-term exposure of Atlantic salmon to water soluble petroleum hydrocarbons

    International Nuclear Information System (INIS)

    Ackman, R.G.; Heras, H.

    1992-01-01

    Experiments were conducted to examine the extent of tainting of salmon by exposure to the soluble fraction of petroleum hydrocarbons. The experiments were conducted on Atlantic salmon in tanks containing seawater artificially contaminated at three different concentrations with the soluble fraction of a North Sea crude. The salmon flesh was analyzed by gas chromatography and taste tests were conducted on cooked salmon samples to determine the extent of tainting. Salmon in control tanks with uncontaminated seawater had muscle accumulations of total hydrocarbons of ca 1 ppM. The muscle accumulations of total hydrocarbons in the salmon were 13.5 ppM, 25.6 ppM, and 31.3 ppM for water soluble fraction concentrations of 0.45, 0.87, and 1.54 ppM respectively. The threshold for taint was clearly inferred to be less than 0.45 ppM of water soluble fraction. 18 refs., 2 figs

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

    Science.gov (United States)

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

    2015-03-01

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

  4. Terrestrial Water Flux Responses to Global Warming in Tropical Rainforest Area

    Science.gov (United States)

    Lan, C. W.; Lo, M. H.; Kumar, S.

    2016-12-01

    Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. In this study, Coupled Model Intercomparison Project Phase 5 (CMIP5) archives have been examined to explore the changes in normalized terrestrial water fluxes (TWFn) (precipitation minus evapotranspiration minus total runoff, divided by the precipitation climatology) in three tropical rainforest areas: Maritime Continent, Congo, and Amazon. Results reveal that a higher frequency of intense precipitation events is predicted for the Maritime Continent in the future climate than in the present climate, but not for the Amazon or Congo rainforests. Nonlinear responses to extreme precipitation lead to a reduced groundwater recharge and a proportionately greater amount of direct runoff, particularly for the Maritime Continent, where both the amount and intensity of precipitation increase under global warming. We suggest that the nonlinear response is related to the existence of a higher near-surface soil moisture over the Maritime Continent than that over the Amazon and Congo rainforests. The wetter soil over the Maritime Continent also leads to an increased subsurface runoff. Thus, increased precipitation extremes and concomitantly reduced terrestrial water fluxes (TWF) lead to an intensified hydrological cycle for the Maritime Continent. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem of the rainforest region and increasing the risk of flooding and/or landslides.

  5. Terrestrial water flux responses to global warming in tropical rainforest areas

    Science.gov (United States)

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

    2016-05-01

    Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. In this study, Coupled Model Intercomparison Project Phase 5 archives have been examined to explore the changes in normalized terrestrial water fluxes (precipitation minus evapotranspiration minus total runoff, divided by the precipitation climatology) in three tropical rainforest areas: Maritime Continent, Congo, and Amazon. Results show that a higher frequency of intense precipitation events is predicted for the Maritime Continent in the future climate than in the present climate, but not for the Amazon or Congo rainforests. Nonlinear responses to extreme precipitation lead to a reduced groundwater recharge and a proportionately greater amount of direct runoff, particularly for the Maritime Continent, where both the amount and intensity of precipitation increase under global warming. We suggest that the nonlinear response is related to the existence of a higher near-surface soil moisture over the Maritime Continent than that over the Amazon and Congo rainforests. The wetter soil over the Maritime Continent also leads to an increased subsurface runoff. Thus, increased precipitation extremes and concomitantly reduced terrestrial water fluxes lead to an intensified hydrological cycle for the Maritime Continent. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem of the rainforest region and increasing the risk of flooding and/or landslides.

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  7. Shrubland carbon sink depends upon winter water availability in the warm deserts of North America

    Science.gov (United States)

    Biederman, Joel A.; Scott, Russell L.; John A. Arnone,; Jasoni, Richard L.; Litvak, Marcy E.; Moreo, Michael T.; Papuga, Shirley A.; Ponce-Campos, Guillermo E.; Schreiner-McGraw, Adam P.; Vivoni, Enrique R.

    2018-01-01

    Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of the land CO2 sink. However, such model-based analyses are poorly constrained by measured CO2 exchange in open shrublands, which is the most common global land cover type, covering ∼14% of Earth’s surface. Here we evaluate how the amount and seasonal timing of water availability regulate CO2 exchange between shrublands and the atmosphere. We use eddy covariance data from six US sites across the three warm deserts of North America with observed ranges in annual precipitation of ∼100–400mm, annual temperatures of 13–18°C, and records of 2–8 years (33 site-years in total). The Chihuahuan, Sonoran and Mojave Deserts present gradients in both mean annual precipitation and its seasonal distribution between the wet-winter Mojave Desert and the wet-summer Chihuahuan Desert. We found that due to hydrologic losses during the wettest summers in the Sonoran and Chihuahuan Deserts, evapotranspiration (ET) was a better metric than precipitation of water available to drive dryland CO2 exchange. In contrast with recent synthesis studies across diverse dryland biomes, we found that NEP could not be directly predicted from ET due to wintertime decoupling of the relationship between ecosystem respiration (Reco) and gross ecosystem productivity (GEP). Ecosystem water use efficiency (WUE=GEP/ET) did not differ between winter and summer. Carbon use efficiency (CUE=NEP/GEP), however, was greater in winter because Reco returned a smaller fraction of carbon to the atmosphere (23% of GEP) than in summer (77%). Combining the water-carbon relations found here with historical precipitation since 1980, we estimate that lower average winter precipitation during the 21st century reduced the net carbon sink of the three deserts by an average of 6.8TgC yr1. Our results highlight that winter precipitation is critical to the annual carbon balance of these

  8. WATER TEMPERATURE and other data from OLEANDER and Skogafoss in the NW Atlantic, North Atlantic Ocean and Stellwagen Bank National Marine Sanctuary from 1994-01-05 to 1994-12-19 (NODC Accession 9500005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The water depth and temperature data was collected in NW Atlantic (limit-40 W) from ships OLEANDER and SKOGAFOSS as part of Ship Of Opportunity Programme (SOOP). The...

  9. Thermal Habitat Index of Many Northwest Atlantic Temperate Species Stays Neutral under Warming Projected for 2030 but Changes Radically by 2060

    Czech Academy of Sciences Publication Activity Database

    Shackell, N.L.; Ricard, Daniel; Stortini, C.

    2014-01-01

    Roč. 9, č. 3 (2014), e90662 E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : climate change * environmental parameters * Atlantic Ocean * greenhouse effect Subject RIV: EH - Ecology, Behaviour Impact factor: 3.234, year: 2014

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

    Science.gov (United States)

    Isobe, Atsuhiko

    1995-06-01

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

  11. Southeast Regional Implementation Manual for Requirements and Procedures for Evaluation of the Ocean Disposal of Dredged Material in Southeastern U.S. Atlantic and Gulf Coast Waters

    Science.gov (United States)

    This Regional Implementation Manual was prepared by EPA Region 4 to provide guidance for applicants proposing open-water disposal of dredged material in southeastern U.S. coastal waters of the Atlantic Ocean and the Gulf of Mexico.

  12. Non-methane biogenic volatile organic compound emissions from boreal peatland microcosms under warming and water table drawdown

    DEFF Research Database (Denmark)

    Faubert, P; Tiiva, P; Nakam, TA

    2011-01-01

    assessed the combined effect of warming and water table drawdown on the BVOC emissions from boreal peatland microcosms. We also assessed the treatment effects on the BVOC emissions from the peat soil after the 7-week long experiment. Emissions of isoprene, monoterpenes, sesquiterpenes, other reactive VOCs...

  13. Will Global Warming Cause a Rise in Sea Level? A Simple Activity about the States of Water

    Science.gov (United States)

    Oguz, Ayse

    2009-01-01

    In this activity, a possible problem related to global warming is clarified by the principle of states of water. The activity consists of an experiment that includes three scientific principles: Archimedes' Principle, the Law of Conservation of Matter, and the fluidity of liquids. The experiment helps students raise questions and open new horizons…

  14. Abrupt stop of deep water turnover with lake warming: Drastic consequences for algal primary producers.

    Science.gov (United States)

    Yankova, Yana; Neuenschwander, Stefan; Köster, Oliver; Posch, Thomas

    2017-10-23

    After strong fertilization in the 20 th century, many deep lakes in Central Europe are again nutrient poor due to long-lasting restoration (re-oligotrophication). In line with reduced phosphorus and nitrogen loadings, total organismic productivity decreased and lakes have now historically low nutrient and biomass concentrations. This caused speculations that restoration was overdone and intended fertilizations are needed to ensure ecological functionality. Here we show that recent re-oligotrophication processes indeed accelerated, however caused by lake warming. Rising air temperatures strengthen thermal stabilization of water columns which prevents thorough turnover (holomixis). Reduced mixis impedes down-welling of oxygen rich epilimnetic (surface) and up-welling of phosphorus and nitrogen rich hypolimnetic (deep) water. However, nutrient inputs are essential for algal spring blooms acting as boost for annual food web successions. We show that repeated lack (since 1977) and complete stop (since 2013) of holomixis caused drastic epilimnetic phosphorus depletions and an absence of phytoplankton spring blooms in Lake Zurich (Switzerland). By simulating holomixis in experiments, we could induce significant vernal algal blooms, confirming that there would be sufficient hypolimnetic phosphorus which presently accumulates due to reduced export. Thus, intended fertilizations are highly questionable, as hypolimnetic nutrients will become available during future natural or artificial turnovers.

  15. Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model

    Directory of Open Access Journals (Sweden)

    A. Gnanadesikan

    2012-03-01

    Full Text Available Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1 shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., suboxic waters does not increase under global warming, as these waters actually become more oxygenated. We show that the rise in dissolved oxygen in the tropical Pacific is associated with a drop in ventilation time. A term-by-term analysis within the least oxygenated waters shows an increased supply of dissolved oxygen due to lateral diffusion compensating an increase in remineralization within these highly hypoxic waters. This lateral diffusive flux is the result of an increase of ventilation along the Chilean coast, as a drying of the region under global warming opens up a region of wintertime convection in our model. The results highlight the potential sensitivity of suboxic waters to changes in subtropical ventilation as well as the importance of constraining lateral eddy transport of dissolved oxygen in such waters.

  16. Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model

    Science.gov (United States)

    Gnanadesikan, A.; Dunne, J. P.; John, J.

    2012-03-01

    Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1) shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., suboxic) waters does not increase under global warming, as these waters actually become more oxygenated. We show that the rise in dissolved oxygen in the tropical Pacific is associated with a drop in ventilation time. A term-by-term analysis within the least oxygenated waters shows an increased supply of dissolved oxygen due to lateral diffusion compensating an increase in remineralization within these highly hypoxic waters. This lateral diffusive flux is the result of an increase of ventilation along the Chilean coast, as a drying of the region under global warming opens up a region of wintertime convection in our model. The results highlight the potential sensitivity of suboxic waters to changes in subtropical ventilation as well as the importance of constraining lateral eddy transport of dissolved oxygen in such waters.

  17. Photosynthetic capacity and intrinsic water-use efficiency of Rhizophora mangle at its southernmost western Atlantic range

    Science.gov (United States)

    M.L.G. Soares; M.M.P. Tognella; E. Cuevas; E. Medina

    2015-01-01

    The southernmost presence of Rhizophora mangle in the western Atlantic coast occurs in coastal wetlands between 27 and 28ºS in the State of Santa Catarina, Brazil. We selected mangrove communities at the estuary of Rio Tavares, Florianopolis, and Sonho Beach, Palhosa, for measurement of photosynthetic performance and intrinsic water use efficiency of R. mangle and...

  18. INACTIVATION OF MS2 VIRUS IN DRINKING WATER: ATLANTIC ULTRAVIOLET CORPORATION MEGATRON UNIT, MODEL M250 AT CHULA VISTA, CALIFORNIA

    Science.gov (United States)

    Verification testing of the Atlantic Ultraviolet Megatron M250 system was conducted over a 48-day period from 11/01/01 to 12/18/01. The feedwater to the ultraviolet (UV) unit during the testing was effluent from the Otay Water Treatment Plant (OWTP), a conventional plant with fl...

  19. Evaluation of partial water reuse systems used for Atlantic salmon smolt production at the White River National Fish Hatchery

    Science.gov (United States)

    Eight of the existing 9.1 m (30 ft) diameter circular culture tanks at the White River National Fish Hatchery in Bethel, Vermont, were retrofitted and plumbed into two 8,000 L/min partial water reuse systems to help meet the region's need for Atlantic salmon (Salmo salar) smolt production. The part...

  20. Organic matter processing by microbial communities throughout the Atlantic water column as revealed by metaproteomics

    DEFF Research Database (Denmark)

    Bergauer, Kristin; Fernandez-Guerra, Antonio; Garcia, Juan A L

    2018-01-01

    The phylogenetic composition of the heterotrophic microbial community is depth stratified in the oceanic water column down to abyssopelagic layers. In the layers below the euphotic zone, it has been suggested that heterotrophic microbes rely largely on solubilized particulate organic matter...... as a carbon and energy source rather than on dissolved organic matter. To decipher whether changes in the phylogenetic composition with depth are reflected in changes in the bacterial and archaeal transporter proteins, we generated an extensive metaproteomic and metagenomic dataset of microbial communities...... collected from 100- to 5,000-m depth in the Atlantic Ocean. By identifying which compounds of the organic matter pool are absorbed, transported, and incorporated into microbial cells, intriguing insights into organic matter transformation in the deep ocean emerged. On average, solute transporters accounted...

  1. Stock structure of Atlantic herring Clupea harengus in the Norwegian Sea and adjacent waters

    DEFF Research Database (Denmark)

    Pampoulie, Christophe; Slotte, Aril; Oskarsson, Guomundur J.

    2015-01-01

    The genetic structure of Atlantic herring Clupea harengus L. was investigated in its north-easterly distribution in the Norwegian Sea and adjacent waters, using 23 neutral and one non-neutral (Cpa111) microsatellite loci. Fish from the suspected 2 main populations-the Norwegian spring......-spawning herring (NSSH) and the Icelandic summer-spawning herring (ISSH)-were collected at spawning locations in their respective spawning seasons from 2009 to 2012. Samples were also collected from Norwegian autumn spawning locations, from different local Norwegian fjords such as the inner part...... of Trondheimsfjorden, Lindas pollene, Landvikvannet and Lusterfjorden, as well as from suspected Faroese spawning components. The observed level of genetic differentiation was significant but low (F-ST = 0.007) and mostly attributable to the differentiation of the local Norwegian fjord populations. The locus Cpa111...

  2. Potential impacts of climate warming on water supply reliability in the Tuolumne and Merced River Basins, California.

    Directory of Open Access Journals (Sweden)

    Michael Kiparsky

    Full Text Available We present an integrated hydrology/water operations simulation model of the Tuolumne and Merced River Basins, California, using the Water Evaluation and Planning (WEAP platform. The model represents hydrology as well as water operations, which together influence water supplied for agricultural, urban, and environmental uses. The model is developed for impacts assessment using scenarios for climate change and other drivers of water system behavior. In this paper, we describe the model structure, its representation of historical streamflow, agricultural and urban water demands, and water operations. We describe projected impacts of climate change on hydrology and water supply to the major irrigation districts in the area, using uniform 2 °C, 4 °C, and 6 °C increases applied to climate inputs from the calibration period. Consistent with other studies, we find that the timing of hydrology shifts earlier in the water year in response to temperature warming (5-21 days. The integrated agricultural model responds with increased water demands 2 °C (1.4-2.0%, 4 °C (2.8-3.9%, and 6 °C (4.2-5.8%. In this sensitivity analysis, the combination of altered hydrology and increased demands results in decreased reliability of surface water supplied for agricultural purposes, with modeled quantity-based reliability metrics decreasing from a range of 0.84-0.90 under historical conditions to 0.75-0.79 under 6 °C warming scenario.

  3. Thermal Thresholds of Phytoplankton Growth in Polar Waters and Their Consequences for a Warming Polar Ocean

    KAUST Repository

    Coello-Camba, Alexandra

    2017-06-02

    Polar areas are experiencing the steepest warming rates on Earth, a trend expected to continue in the future. In these habitats, phytoplankton communities constitute the basis of the food web and their thermal tolerance may dictate how warming affects these delicate environments. Here, we compiled available data on thermal responses of phytoplankton growth in polar waters. We assembled 53 growth-vs.-temperature curves (25 from the Arctic, 28 from the Southern oceans), indicating the limited information available for these ecosystems. Half of the data from Arctic phytoplankton came from natural communities where low ambient concentrations could limit growth rates. Phytoplankton from polar waters grew faster under small temperature increases until reaching an optimum (TOPT), and slowed when temperatures increased beyond this value. This left-skewed curves were characterized by higher activation energies (Ea) for phytoplankton growth above than below the TOPT. Combining these thermal responses we obtained a community TOPT of 6.5°C (±0.2) and 5.2°C (±0.1) for Arctic and Southern Ocean phytoplankton communities, respectively. These threshold temperatures were already exceeded at 70°N during the first half of August 2013, evidenced by sea surface temperatures (SSTs, satellite data, http://www.ncdc.noaa.gov). We forecasted SSTs for the end of the twenty-first century by assuming an overall 3°C increase, equivalent to a low emission scenario. Our forecasts show that SSTs at 70°N are expected to exceed TOPT during summer by 2100, and during the first half of August at 75°N. While recent Arctic spring temperatures average 0.5°C and −0.7°C at 70°N and 75°N, respectively, they could increase to 2.8°C at 70°N and 2.2°C at 75°N as we approach 2100. Such temperature increases could lead to intense phytoplankton blooms, shortened by fast nutrient consumption. As SSTs increase, thermal thresholds for phytoplankton growth would be eventually exceeded during bloom

  4. Thermal Thresholds of Phytoplankton Growth in Polar Waters and Their Consequences for a Warming Polar Ocean

    Directory of Open Access Journals (Sweden)

    Alexandra Coello-Camba

    2017-06-01

    Full Text Available Polar areas are experiencing the steepest warming rates on Earth, a trend expected to continue in the future. In these habitats, phytoplankton communities constitute the basis of the food web and their thermal tolerance may dictate how warming affects these delicate environments. Here, we compiled available data on thermal responses of phytoplankton growth in polar waters. We assembled 53 growth-vs.-temperature curves (25 from the Arctic, 28 from the Southern oceans, indicating the limited information available for these ecosystems. Half of the data from Arctic phytoplankton came from natural communities where low ambient concentrations could limit growth rates. Phytoplankton from polar waters grew faster under small temperature increases until reaching an optimum (TOPT, and slowed when temperatures increased beyond this value. This left-skewed curves were characterized by higher activation energies (Ea for phytoplankton growth above than below the TOPT. Combining these thermal responses we obtained a community TOPT of 6.5°C (±0.2 and 5.2°C (±0.1 for Arctic and Southern Ocean phytoplankton communities, respectively. These threshold temperatures were already exceeded at 70°N during the first half of August 2013, evidenced by sea surface temperatures (SSTs, satellite data, http://www.ncdc.noaa.gov. We forecasted SSTs for the end of the twenty-first century by assuming an overall 3°C increase, equivalent to a low emission scenario. Our forecasts show that SSTs at 70°N are expected to exceed TOPT during summer by 2100, and during the first half of August at 75°N. While recent Arctic spring temperatures average 0.5°C and −0.7°C at 70°N and 75°N, respectively, they could increase to 2.8°C at 70°N and 2.2°C at 75°N as we approach 2100. Such temperature increases could lead to intense phytoplankton blooms, shortened by fast nutrient consumption. As SSTs increase, thermal thresholds for phytoplankton growth would be eventually exceeded

  5. Thermal Thresholds of Phytoplankton Growth in Polar Waters and Their Consequences for a Warming Polar Ocean

    KAUST Repository

    Coello-Camba, Alexandra; Agusti, Susana

    2017-01-01

    Polar areas are experiencing the steepest warming rates on Earth, a trend expected to continue in the future. In these habitats, phytoplankton communities constitute the basis of the food web and their thermal tolerance may dictate how warming affects these delicate environments. Here, we compiled available data on thermal responses of phytoplankton growth in polar waters. We assembled 53 growth-vs.-temperature curves (25 from the Arctic, 28 from the Southern oceans), indicating the limited information available for these ecosystems. Half of the data from Arctic phytoplankton came from natural communities where low ambient concentrations could limit growth rates. Phytoplankton from polar waters grew faster under small temperature increases until reaching an optimum (TOPT), and slowed when temperatures increased beyond this value. This left-skewed curves were characterized by higher activation energies (Ea) for phytoplankton growth above than below the TOPT. Combining these thermal responses we obtained a community TOPT of 6.5°C (±0.2) and 5.2°C (±0.1) for Arctic and Southern Ocean phytoplankton communities, respectively. These threshold temperatures were already exceeded at 70°N during the first half of August 2013, evidenced by sea surface temperatures (SSTs, satellite data, http://www.ncdc.noaa.gov). We forecasted SSTs for the end of the twenty-first century by assuming an overall 3°C increase, equivalent to a low emission scenario. Our forecasts show that SSTs at 70°N are expected to exceed TOPT during summer by 2100, and during the first half of August at 75°N. While recent Arctic spring temperatures average 0.5°C and −0.7°C at 70°N and 75°N, respectively, they could increase to 2.8°C at 70°N and 2.2°C at 75°N as we approach 2100. Such temperature increases could lead to intense phytoplankton blooms, shortened by fast nutrient consumption. As SSTs increase, thermal thresholds for phytoplankton growth would be eventually exceeded during bloom

  6. Soil, water, and nutrient losses from management alternatives for degraded pasture in Brazilian Atlantic Rainforest biome.

    Science.gov (United States)

    Rocha Junior, Paulo Roberto da; Andrade, Felipe Vaz; Mendonça, Eduardo de Sá; Donagemma, Guilherme Kangussú; Fernandes, Raphael Bragança Alves; Bhattharai, Rabin; Kalita, Prasanta Kumar

    2017-04-01

    The objective of this study was to evaluate sediment, water and nutrient losses from different pasture managements in the Atlantic Rainforest biome. A field study was carried out in Alegre Espiríto Santo, Brazil, on a Xanthic Ferralsol cultivated with braquiaria (Brachiaria brizantha). The six pasture managements studied were: control (CON), chisel (CHI), fertilizer (FER), burned (BUR), plowing and harrowing (PH), and integrated crop-livestock (iCL). Runoff and sediment samples were collected and analyzed for calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P) and organic carbon contents. Soil physical attributes and above and below biomass were also evaluated. The results indicated that higher water loss was observed for iCL (129.90mm) and CON (123.25mm) managements, and the sediment losses were higher for CON (10.24tha -1 ) and BUR (5.20tha -1 ) managements when compared to the other managements. Majority of the nutrients losses occurred in dissolved fraction (99% of Ca, 99% of Mg, 96% of K, and 65% of P), whereas a significant fraction of organic carbon (80%) loss occurred in a particulate form. Except for P, other nutrients (Ca, Mg and K) and organic carbon losses were higher in coarse sediment compared to fine sediment. The greater losses of sediment, organic carbon, and nutrients were observed for CON followed by BUR management (plosses from various practices, to reduce pasture degradation, farmers should adopt edaphic practices by applying lime and fertilize to improve pasture growth and soil cover, and reducing soil erosion in the hilly Brazilian Atlantic Rainforest biome. Copyright © 2016. Published by Elsevier B.V.

  7. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature.

    Science.gov (United States)

    Norambuena, Fernando; Morais, Sofia; Emery, James A; Turchini, Giovanni M

    2015-01-01

    Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3), with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar) kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad-time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher water temperature

  8. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature.

    Directory of Open Access Journals (Sweden)

    Fernando Norambuena

    Full Text Available Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3, with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad-time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher

  9. Effects of chronic produced water exposure on the expression of some immune-related genes of juvenile Atlantic cod

    International Nuclear Information System (INIS)

    Perez Casanova, J.; Hamoutene, D.; Samuelson, S.; Burt, K.; King, T.; Lee, K.

    2010-01-01

    This study assessed the impacts of exposure to processed water produced by offshore oil operators on immune-related genes of juvenile Atlantic cod exposed to processed water for a period of 22 weeks. The study investigated the influence of processed water concentrations on growth parameters; food consumption; plasma cortisol; respiratory burst activity (RB); and mRNA expression. The study showed that the RB of circulating leukocytes was significantly elevated. Significant up-regulation of the mRNA expression of microglobulin, immunoglobulin light chain, and interleukins was observed in some fish. The down-regulation of the interferon stimulated gene was also observed. The study indicated that chronic exposure to significant amounts of processed water causes modulations of the immune system of juvenile Atlantic cod.

  10. Effects of chronic produced water exposure on the expression of some immune-related genes of juvenile Atlantic cod

    Energy Technology Data Exchange (ETDEWEB)

    Perez Casanova, J.; Hamoutene, D.; Samuelson, S.; Burt, K.; King, T. [Fisheries and Oceans Canada, St. John' s, NL (Canada); Lee, K. [Fisheries and Oceans Canada, Dartmouth, NS (Canada)

    2010-07-01

    This study assessed the impacts of exposure to processed water produced by offshore oil operators on immune-related genes of juvenile Atlantic cod exposed to processed water for a period of 22 weeks. The study investigated the influence of processed water concentrations on growth parameters; food consumption; plasma cortisol; respiratory burst activity (RB); and mRNA expression. The study showed that the RB of circulating leukocytes was significantly elevated. Significant up-regulation of the mRNA expression of microglobulin, immunoglobulin light chain, and interleukins was observed in some fish. The down-regulation of the interferon stimulated gene was also observed. The study indicated that chronic exposure to significant amounts of processed water causes modulations of the immune system of juvenile Atlantic cod.

  11. Sea-water/groundwater interactions along a small catchment of the European Atlantic coast

    International Nuclear Information System (INIS)

    Einsiedl, Florian

    2012-01-01

    The geochemistry and isotopic composition of a karstic coastal aquifer in western Ireland has shed light on the effect of sea-water/groundwater interactions on the water quality of Ireland’s Atlantic coastal zone. The use of stable isotope data from the IAEA precipitation station in Valentia, located in SW Ireland has facilitated the characterization of groundwater recharge conditions in the western part of Ireland and suggests that groundwater is mostly replenished by the isotopically light winter precipitation. The dissolved SO 4 2- in the karstic groundwater that was collected during baseflow conditions with δ 34 S values between 4.6‰ and 18‰ may be composed of S stemming from three principal sources: SO 4 2- derived from precipitation which is composed of both sea-spray S (δ 34 S: 20‰) and an isotopically light anthropogenic source (δ 34 S: 1–5‰), SO 4 2- stemming from animal slurries (δ 34 S: ∼5‰), and intruding sea-water SO 4 2- (δ 34 S: 20.2‰). The isotopic composition of δ 18 O in dissolved groundwater SO 4 2- collected during baseflow conditions is interpreted as reflecting sea-water intrusion to the karstic coastal groundwater system. The highest δ 18 O values in dissolved groundwater SO 4 2- were in samples collected near the coast (4.8 ± 0.4‰) and the lowest (2 ± 0.5‰) were collected further inland. The δ 15 N and δ 18 O values of groundwater NO 3 - were between 3.4‰ and 11.4‰ and approximately 7.7‰, respectively, and reflect geochemical conditions in the aquifer that do not promote attenuation of NO 3 - through denitrification. As a result N loading to Kinvara Bay that is controlled by submarine groundwater discharge (SGD) was calculated as 5 tons/day on average compared to an estimated N-input that derives from precipitation of approximately 2.5 tons/a. SGD into the bay may result in near coastal sea-water quality changes. These results represent one of the first studies addressing the effect of groundwater

  12. Evolution of Interhemispheric Sea-Surface Temperature Contrast in the Tropical Atlantic During Termination I

    Science.gov (United States)

    Kim, J.

    2001-12-01

    Meteorological and oceanographic studies show that interannual and decadal variability in tropical Atlantic sea-surface temperature (SST) strongly influences the climates over northeast Brazil, sub-Saharan Africa, as well as the Central American and Caribbean regions. In this context, it is worthwhile to reconstruct spatial temperature patterns for the longer-term tropical Atlantic SST history. In this study, a high-resolution alkenone-derived SST record from the subtropical eastern South Atlantic (core GeoB 1023-5) is compared with one from the tropical western North Atlantic (core M35003-4). This comparison reveals synchronous SST variations between both near equatorial Atlantic regions during the Heinrich Event 1 (H1) (18-15.5 cal kyr B.P.), but dipole-like SST variations during the Younger Dryas (YD) (13-11.5 cal kyr B.P.). To assess the relationship of SST variations between both regions, we calculated SST differences between cores GeoB 1023-5 and M35003-4, and compared it with the coccolithophorid Florisphaera profunda abundance record from the equatorial eastern Atlantic (core RC24-08) as an indicator of variations in intensity of south-easterly trade winds [McIntyre and Molfino, 1996]. This comparison suggests that synchronous warming in both regions during the H1 can be attributed to a reduced northward heat transport from the warm equatorial Atlantic to the cold high-latitude North Atlantic linked to the slowdown of thermohaline circulation overturning during cold events under full glacial conditions. However, dipole-like SST variations during the YD is probably more associated with strengthened south-easterly trade winds, which led to a strong upwelling-related cooling in the eastern South Atlantic region and concurrently enhanced advection of warm subtropical South Atlantic waters to the tropical western Atlantic during that time. Accordingly, a coupled oceanic-atmospheric process created a warm pool in the tropical western Atlantic and thus a dipole

  13. Temperature-induced water stress in high-latitude forests in response to natural and anthropogenic warming.

    Science.gov (United States)

    Trahan, Matthew W; Schubert, Brian A

    2016-02-01

    The Arctic is particularly sensitive to climate change, but the independent effects of increasing atmospheric CO2 concentration (pCO2 ) and temperature on high-latitude forests are poorly understood. Here, we present a new, annually resolved record of stable carbon isotope (δ(13) C) data determined from Larix cajanderi tree cores collected from far northeastern Siberia in order to investigate the physiological response of these trees to regional warming. The tree-ring record, which extends from 1912 through 1961 (50 years), targets early twentieth-century warming (ETCW), a natural warming event in the 1920s to 1940s that was limited to Northern hemisphere high latitudes. Our data show that net carbon isotope fractionation (Δ(13) C), decreased by 1.7‰ across the ETCW, which is consistent with increased water stress in response to climate warming and dryer soils. To investigate whether this signal is present across the northern boreal forest, we compiled published carbon isotope data from 14 high-latitude sites within Europe, Asia, and North America. The resulting dataset covered the entire twentieth century and spanned both natural ETCW and anthropogenic Late Twentieth-Century Warming (~0.7 °C per decade). After correcting for a ~1‰ increase in Δ(13) C in response to twentieth century pCO2 rise, a significant negative relationship (r = -0.53, P forests across the twentieth century, of which approximately half is attributed to a decrease in stomatal conductance in order to conserve water in response to drying conditions, with the other half being attributed to increasing pCO2 . We conclude that annual tree-ring records from northern high-latitude forests record the effects of climate warming and pCO2 rise across the twentieth century. © 2015 John Wiley & Sons Ltd.

  14. The utilization of ERTS-1 data for the study of the French Atlantic Littoral. [coastal water and geomorphology

    Science.gov (United States)

    Demathieu, P. G.; Verger, F. H.

    1974-01-01

    The French Atlantic Littoral (FRALIT) program uses ERTS-1 data to study coastal geomorphology and waters. ERTS-1 gives an overall picture of the phenomena for the first time due mainly to channel 4 data, but the other channels also contribute valuable complementary data on superficial waters. These studies have already resulted in accurate maps of the mud transported south-westwards from the mouth of the River Loire.

  15. Differentiating leucine incorporation of Archaea and Bacteria throughout the water column of the eastern Atlantic using metabolic inhibitors

    OpenAIRE

    Yokokawa, Taichi; Sintes, Eva; de Corte, Daniele; Olbrich, Kerstin; Herndl, Gerhard J.

    2012-01-01

    The abundance (based on catalyzed reporter deposition-fluorescence in situ hybrid ization, CARD-FISH) and leucine incorporation rates of Archaea and Bacteria were determined throughout the water column in the eastern Atlantic. Bacteria dominated throughout the water column, although their contribution to total prokaryotic abundance in the bathypelagic layer (1000 to 4000 m depth) was lower than in the surface and mesopelagic layers (0 to 1000 m depth). While marine Crenarchaeota Group I (MCG ...

  16. Climatic warming and potential demands for irrigation water in southwest Ontario

    International Nuclear Information System (INIS)

    Brklacich, M.

    1990-01-01

    The potential impacts of global warming on demand for irrigation water in southwestern Ontario are discussed. The climatic change scenarios considered derive from the Goddard Institute for Space Studies (GISS) general circulation model, which suggests that the frost-free season in southwestern Ontario will be extended from the current 166 days to 223 days under a doubling of atmospheric carbon dioxide. The 1.76 million ha of agricultural land in southwestern Ontario was disaggregated into 365 unique land units, reflecting regional variability in soil quality, topography and climate. Analyses were conducted for individual crops on each of the land units, and results were aggregated to a regional level. Overall, a longer, warmer but relatively drier crop growing season could be expected in southwestern Ontario under this scenario. Climatic change impacts will vary from crop to crop, and will have a greater impact on corn yield than soybeans or wheat. Yield improvements stemming from irrigation should be greater with corn than with the other two crops. 16 refs., 1 tab

  17. Shape Recovery with Concomitant Mechanical Strengthening of Amphiphilic Shape Memory Polymers in Warm Water

    International Nuclear Information System (INIS)

    Zhang, Ben; DeBartolo, Janae E.; Song, Jie

    2017-01-01

    Maintaining adequate or enhancing mechanical properties of shape memory polymers (SMPs) after shape recovery in an aqueous environment are greatly desired for biomedical applications of SMPs as self-fitting tissue scaffolds or minimally invasive surgical implants. Here we report stable temporary shape fixing and facile shape recovery of biodegradable triblock amphiphilic SMPs containing a poly(ethylene glycol) (PEG) center block and flanking poly(lactic acid) or poly(lactic-co-glycolic acid) blocks in warm water, accompanied with concomitant enhanced mechanical strengths. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD) and small-angle X-ray scattering (SAXS) analyses revealed that the unique stiffening of the amphiphilic SMPs upon hydration was due to hydration-driven microphase separation and PEG crystallization. We further demonstrated that the chemical composition of degradable blocks in these SMPs could be tailored to affect the persistence of hydration-induced stiffening upon subsequent dehydration. These properties combined open new horizons for these amphiphilic SMPs for smart weight-bearing in vivo applications (e.g. as self-fitting intervertebral discs). In conclusion, this study also provides a new material design strategy to strengthen polymers in aqueous environment in general.

  18. Changes in water mass exchange between the NW shelf areas and the North Atlantic and their impact on nutrient/carbon cycling

    Science.gov (United States)

    Gröger, Matthias; Maier-Reimer, Ernst; Mikolajewicz, Uwe; Segschneider, Joachim; Sein, Dimitry

    2010-05-01

    Despite their comparatively small extension on a global scale, shelf areas are of interest for several economic reasons and climatic processes related to nutrient cycling, sea food supply, and biological productivity. Moreover, they constitute an important interface for nutrients, pollutants and freshwater on their pathway from the continents to the open ocean. This modelling study aims to investigate the spatial and temporal variability of water mass exchange between the North Atlantic and the NW European shelf and their impact on nutrient/carbon cycling and biological productivity. For this, a new modeling approach has been set up which bridges the gap between pure shelf models where water mass transports across the model domain too strongly depend on the formulation of open boundaries and global models suffering under their too coarse resolution in shelf regions. The new model consists of the global ocean and carbon cycle model MPIOM/HAMOCC with strongly increased resolution in the North Sea and the North Atlantic coupled to the regional atmosphere model REMO. The model takes the full luni-solar tides into account. It includes further a 12 layer sediment module with the relevant pore water chemistry. The main focus lies on the governing mechanisms of water mass exchange across the shelf break and the imprint on shelf biogeochemistry. For this, artificial tracers with a prescribed decay rate have been implemented to distinguish waters arriving from polar and shelf regions and those that originate from the tropics. Experiments were carried out for the years 1948 - 2007. The relationship to larger scale circulation patterns like the position and variability of the subtropical and subpolar gyres is analyzed. The water mass exchange is analyzed with respect to the nutrient concentration and productivity on the European shelf areas. The implementation of tides leads to an enhanced vertical mixing which causes lower sea surface temperatures compared to simulations

  19. Evidence for the bioerosion of deep-water corals by echinoids in the Northeast Atlantic

    Science.gov (United States)

    Stevenson, Angela; Rocha, Carlos

    2013-01-01

    In situ video observations of echinoids interacting with deep-sea coral are common in the deep-sea, but paradoxically the deep-sea literature is devoid of reports of bioerosion by extant echinoids. Here we present evidence of contemporary bioerosion of cold-water coral by four species of deep-sea echinoids, Gracilechinus elegans, Gracilechinus alexandri, Cidaris cidaris, and Araeosoma fenestratum, showing that they actively predate on the living framework of reef building corals, Lophelia pertusa and Madrepora oculata, in the NE Atlantic. Echinoid specimens were collected in six canyons located in the Bay of Biscay, France and two canyons on the north side of the Porcupine Bank and Goban Spur, Ireland. A total of 44 live specimens from the four taxa (9 of G. elegans, 4 of G. alexandri, 21 of C. cidaris and 10 of A. fenestratum) showed recent ingestion of the coral infrastructure. Upon dissection, live coral skeleton was observed encased in a thick mucus layer within the gastrointestinal tract of G. elegans and G. alexandri while both live and dead coral fragments were found in C. cidaris and A. fenestratum. Echinoid bioerosion limits the growth of shallow-water reefs. Our observations suggest that echinoids may also play an important role in the ecology of deep-water coral reefs.

  20. Water-soluble elements in atmospheric particulate matter over tropical and equatorial Atlantic

    International Nuclear Information System (INIS)

    Buat-Menard, Patrick; Morelli, Jacques; Chesselet, Roger

    1974-01-01

    Samples of water-soluble atmospheric particulate matter collected from R/V ''Jean Charcot'' (May to October 1971) and R/V ''James Gilliss'' (October 1972) over Tropical and Equatorial Atlantic were analyzed for Na, Mg, K and Ca by atomic absorption and for Cl and S as SO 4 by colorimetry. Data shows a strong geographical dependence of K and Ca enrichment relative to their elemental ratio to Na in sea-water. Ca enrichment is related to presence of identified soluble calcium minerals in continental dust originating from African deserts (Sahara-Kalahari). This dust does not influence amounts of K in the water-soluble phase. When observed, strong K enrichment appears tightly associated with high concentrations of surface-active organic material in the microlayer derived from high biological activity (Gulf of Guinea). Observed in same samples, SO 4 enrichment could also be controlled by the same source. This SO 4 enrichment balances the observed Cl loss in aerosols accordingly with gaseous HCl formation processes in marine atmosphere [fr

  1. The effects of production water, WAF or CEWAF on the fertilization success of Atlantic cod eggs

    International Nuclear Information System (INIS)

    Burridge, L; Wong, D.; Trippel, E.

    2010-01-01

    Production water (PW), dispersed oil, and oil released from offshore oil and gas platforms can adversely affect fish populations. In this study, eggs from Atlantic cod were fertilized in the presence of PW collected from the Terra Nova and Hibernia offshore platforms in 2008. Cod eggs were also fertilized in the presence of the water accommodated fraction (WAF) and chemically enhanced water accommodated fraction (CEWAF) of Alaskan North Slope oil (ANS). Results of the study showed that exposure to the Terra Nova PW at 12 per cent (V/V) or higher resulted in significantly lower fertilization rates than those observed in controls. Exposure to Hibernia PW at 0.5 per cent (V/V) also resulted in significantly lower fertilization rates. The WAF of ANS up to 25 per cent (V/V) had no effect on fertilization rates. At 50 per cent (V/V), the fertilization rate for WAF ANS was much lower than rates observed in controls. The CEWAF significantly reduced fertilization at all tested concentrations.

  2. Atlantic Water advection vs. glacier dynamics in northern Spitsbergen since early deglaciation

    Directory of Open Access Journals (Sweden)

    M. Bartels

    2017-11-01

    Full Text Available Atlantic Water (AW advection plays an important role in climatic, oceanographic and environmental conditions in the eastern Arctic. Situated along the only deep connection between the Atlantic and the Arctic oceans, the Svalbard Archipelago is an ideal location to reconstruct the past AW advection history and document its linkage with local glacier dynamics, as illustrated in the present study of a 275 cm long sedimentary record from Woodfjorden (northern Spitsbergen; water depth: 171 m spanning the last  ∼  15 500 years. Sedimentological, micropalaeontological and geochemical analyses were used to reconstruct changes in marine environmental conditions, sea ice cover and glacier activity. Data illustrate a partial break-up of the Svalbard–Barents Sea Ice Sheet from Heinrich Stadial 1 onwards (until  ∼  14.6 ka. During the Bølling–Allerød ( ∼  14.6–12.7 ka, AW penetrated as a bottom water mass into the fjord system and contributed significantly to the destabilization of local glaciers. During the Younger Dryas ( ∼  12.7–11.7 ka, it intruded into intermediate waters while evidence for a glacier advance is lacking. A short-term deepening of the halocline occurred at the very end of this interval. During the early Holocene ( ∼  11.7–7.8 ka, mild conditions led to glacier retreat, a reduced sea ice cover and increasing sea surface temperatures, with a brief interruption during the Preboreal Oscillation ( ∼  11.1–10.8 ka. Due to a  ∼  6000-year gap, the mid-Holocene is not recorded in this sediment core. During the late Holocene ( ∼  1.8–0.4 ka, a slightly reduced AW inflow and lower sea surface temperatures compared to the early Holocene are reconstructed. Glaciers, which previously retreated to the shallower inner parts of the Woodfjorden system, likely advanced during the late Holocene. In particular, topographic control in concert with the reduced

  3. Variations in the Strength of the North Atlantic Bottom water during Holocene.

    Science.gov (United States)

    Kissel, C.; Van Toer, A.; Michel, E.; Cortijo, E.

    2012-04-01

    One aspect of the Past4Future project is to combine multidisciplinary approaches to monitor changes in ocean circulation during previous interglacial periods. In the framework of this project, our study focusses on the changes in the strength of the North Atlantic deep water during the Holocene period using multiproxy analysis (magnetic and sedimentary). The main part of the study has been conducted on two cores located at the western termination of the northern deep channel of the Charlie-Gibbs fracture zone. This natural E-W corridor is bathed by the Iceland-Scotland overflow water (ISOW) when it passes westward out of the Iceland Basin into the western North Atlantic basin. At present, it is also described as the place where southern sourced silicate-rich Lower Deep Water (LDW) derived from the Antarctic Bottom Waters (AABW) are passing westward, mixing with the ISOW. One core had been taken by the R. V. Charcot in 1977 and the second one is a CASQ core taken during the IMAGES-AMOCINT MD168- cruise in the framework of the 06-EuroMARC-FP-008 Project on board the R.V. Marion Dufresne (French Polar Institute, IPEV) in 2008. Radiocarbon ages indicate an average sedimentation rate of about 90 cm/kyr during early Holocene and 50 cm/kyr through middle and late Holocene allowing a data resolution ranging from 40 to 100 years depending on the proxy. We coupled magnetic properties, anisotropy, sortable silt and benthic foraminifera isotopes. On the long term, a decrease in the amount of magnetic particles (normalized by the carbonate content) is first observed from 10 kyr to 8.6 kyr and then from 6 to 2 kyrs before reaching a steady state during the last two millenia. Following Kissel et al. (2009), this indicates a two steps decrease in the ISOW strength. The mean sortable silt shows exactly the same pattern indicating that not only the intensity of the ISOW but the whole deep water mass bathing the sites has decreased. On the short term, a first very prominent event

  4. Competition among warm season C4-cereals influence water use efficiency and competition ratios

    Directory of Open Access Journals (Sweden)

    Amanullah

    2015-12-01

    Full Text Available Water use efficiency (WUE and competition ratio (CR response of three warm season C4-cereals (grasses viz. corn (Zea mays L., cv. Hybrid-5393 VT3, grain sorghum (Sorghum bicolor L. Moench, cv. Hybrid-84G62 PAT, and foxtail millets (Setaria italic, cv. German Strain R in pure and mixed stands under low and high water levels was investigated. The experiment was conducted in pot experiment at Dryland Agriculture Institute, West Texas A&M University, Canyon, Texas, USA, during spring 2010. The objective of this study was to know whether the differences in the competitive ability of different crop species influence WUE or not? The planned mean comparison indicated that the corn WUE was 20, 11, and 6% higher in the mixed stand than in pure stand at 30, 60, and 90 days after emergence (DAE, respectively. The corn plants in pure stand had 91, 72, and 81% higher WUE than the average WUE of sorghum and millets in pure stand at 30, 60, and 90 DAE, respectively. Grain sorghum in pure stand had 70, 32, and 36% higher WUE than that of millets in pure stand at 30, 60, and 90 DAE, respectively. The WUE of three crops in mixed stand was 10 and 8% higher than the two crops mixed stand at the two early stages; but the WUE was 24% less in the three crops mixed stand than the two crops mixed stand at 90 DAE. Corn-mixed stand in two crops (average of corn + sorghum and corn + millets had 78, 74, and 74% higher WUE than the mixed stand of sorghum and millets at 30, 60, and 90 DAE, respectively. Corn and millets mixed stand had 14, 10, and 26% higher WUE than the corn and sorghum mixed stand at 30, 60, and 90 DAE, respectively. The increase in water level decreased WUE at the two late growth stages in all three crop plants. At the early growth stage (30 DAE, WUE increased in all crops at the higher water level. On the basis of CR, corn was found the best competitor, while millets was declared the least competitor in the mixed stands (corn

  5. Radiocaesium and plutonium in Atlantic surface waters from 73oN to 72oS

    International Nuclear Information System (INIS)

    Holm, E.; Roos, P.; Persson, R.B.R.; Livingston, H.D.

    1991-01-01

    During the recent Swedish Antartic research Expedition (SWEDARP 89/89) samples of surface sea water were collected on board the Stena Arctica between Gothenburgh, Sweden and the Antarctic Peninsula. Radio chemical separation was performed for radiocaesium on 200 1 samples and for plutonium on samples between 200 and 1500 1. The results are compared with those of the GEOSECS expedition in the North and South Atlantic in 1972-73 and the Polish expedition in 1977-78. They show that radiocaesium has behaved rather conservatively and that the decrease in surface water concentrations during 16 years is due to physical decay. On the other hand levels of 239+240 Pu have decreased by a factor of 4-5 giving a half life of 7-8 years in open Atlantic surface waters. (Author)

  6. No evidence for a deglacial intermediate water Δ14C anomaly in the SW Atlantic

    Science.gov (United States)

    Sortor, R. N.; Lund, D. C.

    2010-12-01

    Reconstructions of Δ14C from the eastern tropical Pacific show that severe depletions in 14C occurred at intermediate depths during the last deglaciation (Marchitto et al. 2007; Stott et al. 2009). Marchitto et al. (2007) suggested that old radiocarbon from an isolated abyssal reservoir was injected via the Southern Ocean, and that this anomaly was then carried by Antarctic Intermediate Water (AAIW) to the tropical Pacific. However, a core from the southeastern Pacific Ocean near Chile, which is in the direct path of modern-day AAIW, does not exhibit the excursion and therefore casts doubts upon the AAIW mechanism (De Pol-Holz et al. 2010). Here we evaluate whether or not a deglacial 14C anomaly similar to that in the eastern tropical Pacific occurred at intermediate depths in the South Atlantic. We reconstructed Δ14C using planktonic and benthic foraminifera from core KNR159-5-36GGC on the Brazil Margin (27○31’S and 46○28’W, 1268 m depth). In the modern ocean, the hydrography near this core site is heavily influenced by AAIW (Oppo & Horowitz, 2000). Benthic Δ14C values were determined using raw benthic 14C ages and calendar-calibrated planktonic ages. The deglacial benthic Δ14C trend at this site is similar to the atmospheric Δ14C trend, and is consistent with U/Th-dated corals from intermediate depths on the Brazil Margin (Mangini et al. 2010). The amplitude and timing of Δ14C changes in the foraminiferal and coral records are especially congruous during the Mystery Interval. We find no evidence in the southwestern Atlantic of a ~300‰ decrease in intermediate water Δ14C beginning at 18 kyr BP. Changes in reservoir age of ~1000 years are required to create a Baja-like Δ14C anomaly off Brazil, an implausible increase for a subtropical gyre location. Furthermore, the resulting sedimentation rates would be up to ~145 cm/kyr during the deglaciation, an order of magnitude higher than the average sedimentation rate for 36GGC. When our results are

  7. Linking benthic hydrodynamics and cold-water coral occurrences: A high-resolution model study at three cold-water coral provinces in the NE Atlantic

    NARCIS (Netherlands)

    Mohn, C.; Rengstorf, A.; White, M.; Mienis, F.; Soetaert, K.; Grehan, A.; Duineveld, G.

    2014-01-01

    Observations from numerous cold-water coral locations in the NE Atlantic show energetic near-bottom flow dynamics along the European continental margin at individual coral mounds and mound clusters. Dynamics are largely controlled by tide-topography interaction generating and enhancing periodic

  8. Tracing Atlantic Water Signature in the Arctic Sea Ice Cover East of Svalbard

    Directory of Open Access Journals (Sweden)

    Vladimir V. Ivanov

    2012-01-01

    Full Text Available We focus on the Arctic Ocean between Svalbard and Franz Joseph Land in order to elucidate the possible role of Atlantic water (AW inflow in shaping ice conditions. Ice conditions substantially affect the temperature regime of the Spitsbergen archipelago, particularly in winter. We test the hypothesis that intensive vertical mixing at the upper AW boundary releases substantial heat upwards that eventually reaches the under-ice water layer, thinning the ice cover. We examine spatial and temporal variation of ice concentration against time series of wind, air temperature, and AW temperature. Analysis of 1979–2011 ice properties revealed a general tendency of decreasing ice concentration that commenced after the mid-1990s. AW temperature time series in Fram Strait feature a monotonic increase after the mid-1990s, consistent with shrinking ice cover. Ice thins due to increased sensible heat flux from AW; ice erosion from below allows wind and local currents to more effectively break ice. The winter spatial pattern of sea ice concentration is collocated with patterns of surface heat flux anomalies. Winter minimum sea ice thickness occurs in the ice pack interior above the AW path, clearly indicating AW influence on ice thickness. Our study indicates that in the AW inflow region heat flux from the ocean reduces the ice thickness.

  9. Effect of produced water on feeding and metabolism of Atlantic cod (Gadus morhua)

    Energy Technology Data Exchange (ETDEWEB)

    Volkoff, H.; Parrish, C. [Memorial Univ. of Newfoundland, St. John' s, NL (Canada); Hamoutene, D.; Mabrouk, G.; Samuelson, S.; Mansour, A.; Lee, K. [Fisheries and Oceans Canada, Dartmouth, NS (Canada). Maritimes Region, Ocean Sciences Division

    2007-07-01

    This paper addressed concerns regarding potentially detrimental cumulative effects of waste products from oil industry activities on marine organisms around production sites. The metabolic capacities, feeding and digestive physiology of fish have been shown to change with environmental parameters, which could impact the growth and health status of fish populations. In this study, the effects of produced water (PW) on feeding and metabolism of Atlantic cod was investigated by exposing fish to 0.100 ppm (x 10,000 PW dilution) or 200 ppm (x 500 dilution) of PW for 76 days. Throughout the experiment, food intake and mean weight were monitored. In addition, serum lipids, metabolites and gene expression of a brain appetite regulating factor were measured at the end of the experiment. No significant differences were observed in weight gain or food intake between the 3 groups of fish. Serum metabolites and neuropeptide Y expression remained unchanged between groups. The study is ongoing to complete comparative measurements of whole blood fatty acid profiles in plasma. The preliminary results indicate that feeding and metabolism in cod is not affected by produced water.

  10. Exploring the Elevated Water Vapor Signal Associated with Biomass Burning Aerosol over the Southeast Atlantic Ocean

    Science.gov (United States)

    Pistone, Kristina; Redemann, Jens; Wood, Rob; Zuidema, Paquita; Flynn, Connor; LeBlanc, Samuel; Noone, David; Podolske, James; Segal Rozenhaimer, Michal; Shinozuka, Yohei; hide

    2017-01-01

    The quantification of radiative forcing due to the cumulative effects of aerosols, both directly and on cloud properties, remains the biggest source of uncertainty in our understanding of the physical climate. How the magnitude of these effects may be modified by meteorological conditions is an important aspect of this question. The Southeast Atlantic Ocean (SEA), with seasonal biomass burning (BB) smoke plumes overlying a persistent stratocumulus cloud deck, offers a perfect natural observatory in which to study the complexities of aerosol-cloud interactions. The NASA ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign consists of three field deployments over three years (2016-2018) with the goal of gaining a better understanding of the complex processes (direct and indirect) by which BB aerosols affect clouds. We present results from the first ORACLES field deployment, which took place in September 2016 out of Walvis Bay, Namibia. Two NASA aircraft were flown with a suite of aerosol, cloud, radiation, and meteorological instruments for remote-sensing and in-situ observations. A strong correlation was observed between the aircraft-measured pollution indicators (carbon monoxide and aerosol properties) and atmospheric water vapor content, at all altitudes. Atmospheric reanalysis indicates that convective dynamics over the continent, near likely contribute to this elevated signal. Understanding the mechanisms by which water vapor covaries with plume strength is important to quantifying the magnitude of the aerosol direct and semi-direct effects in the region.

  11. Water chemistry and its effects on the physiology and survival of Atlantic salmon Salmo salar smolts

    Science.gov (United States)

    Liebich, T.; McCormick, S.D.; Kircheis, D.; Johnson, K.; Regal, R.; Hrabik, T.

    2011-01-01

    The physiological effects of episodic pH fluctuations on Atlantic salmon Salmo salar smolts in eastern Maine, U.S.A., were investigated. During this study, S. salar smolts were exposed to ambient stream-water chemistry conditions at nine sites in four catchments for 3 and 6 day intervals during the spring S. salar smolt migration period. Plasma chloride, plasma glucose, gill aluminium and gill Na+- and K+-ATPase levels in S. salar smolts were assessed in relation to ambient stream-water chemistry during this migration period. Changes in both plasma chloride and plasma glucose levels of S. salar smolts were strongly correlated with stream pH, and S. salar smolt mortality occurred in one study site with ambient stream pH between 5??6 and 5??8 during the study period. The findings from this study suggest that physiological effects on S. salar smolts are strongly correlated with stream pH and that in rivers and streams with low dissolved organic carbon (DOC) concentrations the threshold for physiological effects and mortality probably occurs at a higher pH and shorter exposure period than in rivers with higher DOC. Additionally, whenever an acidification event in which pH drops below 5??9 coincides with S. salar smolt migration in eastern Maine rivers, there is potential for a significant reduction in plasma ions of S. salar smolts. ?? 2011 The Fisheries Society of the British Isles.

  12. Temperature profile and water depth data collected from USCGC HARRIOT LANE using BT and XBT casts in the NW Atlantic Ocean for 1987-05-31 (NODC Accession 8700225)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC Harriot Lane in the Northwest Atlantic Ocean and TOGA Area - Atlantic...

  13. Observed vulnerability of Filchner-Ronne Ice Shelf to wind-driven inflow of warm deep water

    Science.gov (United States)

    Darelius, E.; Fer, I.; Nicholls, K. W.

    2016-01-01

    The average rate of melting at the base of the large Filchner-Ronne Ice Shelf in the southern Weddell Sea is currently low, but projected to increase dramatically within the next century. In a model study, melt rates increase as changing ice conditions cause a redirection of a coastal current, bringing warm water of open ocean origin through the Filchner Depression and into the Filchner Ice Shelf cavity. Here we present observations from near Filchner Ice Shelf and from the Filchner Depression, which show that pulses of warm water already arrive as far south as the ice front. This southward heat transport follows the eastern flank of the Filchner Depression and is found to be directly linked to the strength of a wind-driven coastal current. Our observations emphasize the potential sensitivity of Filchner-Ronne Ice Shelf melt rates to changes in wind forcing. PMID:27481659

  14. Influence of Ross Sea Bottom Water changes on the warming and freshening of the Antarctic Bottom Water in the Australian-Antarctic Basin

    Directory of Open Access Journals (Sweden)

    K. Shimada

    2012-07-01

    Full Text Available Changes to the properties of Antarctic Bottom Water in the Australian-Antarctic Basin (AA-AABW between the 1990s and 2000s are documented using data from the WOCE Hydrographic Program (WHP and repeated hydrographic surveys. Strong cooling and freshening are observed on isopycnal layers denser than γn = 28.30 kg m−3. Changes in the average salinity and potential temperature below this isopycnal correspond to a basin-wide warming of 1300 ± 200 GW and freshening of 24 ± 3 Gt year−1. Recent changes to dense shelf water in the source regions in the Ross Sea and George V Land can explain the freshening of AA-AABW but not its extensive warming. An alternative mechanism for this warming is a decrease in the supply of AABW from the Ross Sea (RSBW. Hydrographic profiles between the western Ross Sea and George V Land (171–158° E were analyzed with a simple advective-diffusive model to assess the causes of the observed changes. The model suggests that the warming of RSBW observed between the 1970s and 2000s can be explained by a 21 ± 23% reduction in RSBW transport and the enhancement of the vertical diffusion of heat resulting from a 30 ± 7% weakening of the abyssal stratification. The documented freshening of Ross Sea dense shelf water leads to a reduction in both salinity and density stratification. Therefore the direct freshening of RSBW at its source also produces an indirect warming of the RSBW. A simple box model suggests that the changes in RSBW properties and volume transport (a decrease of 6.7% is assumed between the year 1995 and 2005 can explain 51 ± 6% of the warming and 84 ± 10% of the freshening observed in AA-AABW.

  15. Astronomically paced changes in deep-water circulation in the western North Atlantic during the middle Eocene

    Science.gov (United States)

    Vahlenkamp, Maximilian; Niezgodzki, Igor; De Vleeschouwer, David; Bickert, Torsten; Harper, Dustin; Kirtland Turner, Sandra; Lohmann, Gerrit; Sexton, Philip; Zachos, James; Pälike, Heiko

    2018-02-01

    North Atlantic Deep Water (NADW) currently redistributes heat and salt between Earth's ocean basins, and plays a vital role in the ocean-atmosphere CO2 exchange. Despite its crucial role in today's climate system, vigorous debate remains as to when deep-water formation in the North Atlantic started. Here, we present datasets from carbonate-rich middle Eocene sediments from the Newfoundland Ridge, revealing a unique archive of paleoceanographic change from the progressively cooling climate of the middle Eocene. Well-defined lithologic alternations between calcareous ooze and clay-rich intervals occur at the ∼41-kyr beat of axial obliquity. Hence, we identify obliquity as the driver of middle Eocene (43.5-46 Ma) Northern Component Water (NCW, the predecessor of modern NADW) variability. High-resolution benthic foraminiferal δ18O and δ13C suggest that obliquity minima correspond to cold, nutrient-depleted, western North Atlantic deep waters. We thus link stronger NCW formation with obliquity minima. In contrast, during obliquity maxima, Deep Western Boundary Currents were weaker and warmer, while abyssal nutrients were more abundant. These aspects reflect a more sluggish NCW formation. This obliquity-paced paleoceanographic regime is in excellent agreement with results from an Earth system model, in which obliquity minima configurations enhance NCW formation.

  16. Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

    Science.gov (United States)

    Lazarus, Brynne E.; Castanha, Cristina; Germino, Matthew; Kueppers, Lara M.; Moyes, Andrew B.

    2018-01-01

    1.Predictions of upslope range shifts for tree species with warming are based on assumptions of moisture stress at lower elevation limits and low temperature stress at high elevation limits. However, recent studies have shown that warming can reduce tree seedling establishment across the entire gradient from subalpine forest to alpine via moisture limitation. Warming effects also vary with species, potentially resulting in community shifts in high elevation forests. 2.We examined the growth and physiology underlying effects of warming on seedling demographic patterns. We evaluated dry mass (DM), root length, allocation above- and belowground, and relative growth rate (RGR) of whole seedlings, and their ability to avoid or endure water stress via water-use efficiency and resisting turgor loss, for Pinus flexilis, Picea engelmannii and Pinus contorta seeded below, at, and above treeline in experimentally warmed, watered, and control plots in the Rocky Mountains, USA. We expected that growth and allocation responses to warming would relate to moisture status and that variation in drought tolerance traits would explain species differences in survival rates. 3.Across treatments and elevations, seedlings of all species had weak turgor-loss resistance, and growth was marginal with negative RGR in the first growth phase (-0.01 to -0.04 g/g/d). Growth was correlated with soil moisture, particularly in the relatively small-seeded P. contorta and P. engelmannii. P. flexilis, known to have the highest survivorship, attained the greatest DM and longest root but was also the slowest growing and most water-use-efficient. This was likely due to its greater reliance on seed reserves. Seedlings developed 15% less total DM, 25% less root DM, and 11% shorter roots in heated compared to unheated plots. Higher temperatures slightly increased DM, root length and RGR where soils were wettest, but more strongly decreased these variables under drier conditions. 4.Synthesis: The surprising

  17. Overflow Water Pathways in the Subpolar North Atlantic Observed with Deep Floats

    Science.gov (United States)

    Bower, Amy; Furey, Heather; Lozier, Susan

    2017-04-01

    As part of the Overturning in the Subpolar North Atlantic Program (OSNAP), a total of 135 acoustically tracked RAFOS floats have been deployed in the deep boundary currents of the Iceland, Irminger and Labrador Basins, and in the Charlie-Gibbs Fracture Zone, to investigate the pathways of Iceland-Scotland Overflow Water (ISOW) and Denmark Strait Overflow Water (DSOW). Floats were released annually in 2014, 2015 and 2016 at depths between 1800 and 2800 m for two-year missions. The array of sound sources used for tracking was expanded from 10 to 13 moorings in 2016 when it was discovered that wintertime surface roughness was negatively impacting acoustic ranges. The floats from the first setting reveal several examples of persistent , deep coherent eddy motion, including a cyclonic eddy spinning off the tip of Eirik Ridge (southwest of Cape Farewell), a cyclonic eddy in the northeastern Labrador Basin near where anticyclonic Irminger Rings are formed, and an anticyclonic eddy under the North Atlantic Current (NAC) in the central Iceland Basin. A consistent region of boundary-interior exchange was observed near Hamilton Bank on the western boundary of the Labrador Sea. Deep cyclonic recirculation gyres are revealed in all three basins. Floats released in the southward-flowing deep boundary current over the eastern flank of the Reykjanes Ridge show that shallower layers of ISOW peel off to the west and cross the Ridge into the Irminger Basin through various gaps south of 60°N, including the Bight Fracture Zone. These floats tend to turn northward and continue along the slope in the Irminger Basin. Interestingly, floats released at the ISOW level in the CGFZ did not turn into the Irminger Basin as often depicted in deep circulation schematics, but rather drifted west-northwestward toward the Labrador Sea, or eddied around west of the CGFZ and (in some cases) turned southward. This result is consistent with some previous hydrographic and high-resolution model results

  18. Marine ecosystems in alteration under global warming

    International Nuclear Information System (INIS)

    Prestrud, Paal

    2004-01-01

    It is commonly thought among fishermen, researchers and in the fishing industries that the administration and harvesting of the fish resources is more important for the stock of fish than are changes in the climate. However, many scientific investigations now link changes in temperature with changes in the spreading, survival and beginning of life processes. There is solid evidence that there are important changes in progress in the North Atlantic marine ecosystem caused by global warming. If the heating of the water masses continues, it will probably have a large impact on the ocean's productivity and consequently for the fishing industry

  19. Emergent Toxins in North Atlantic Temperate Waters: A Challenge for Monitoring Programs and Legislation

    Directory of Open Access Journals (Sweden)

    Marisa Silva

    2015-03-01

    Full Text Available Harmful Algal Blooms (HAB are complex to manage due to their intermittent nature and their severe impact on the economy and human health. The conditions which promote HAB have not yet been fully explained, though climate change and anthropogenic intervention are pointed as significant factors. The rise of water temperature, the opening of new sea canals and the introduction of ship ballast waters all contribute to the dispersion and establishment of toxin-producing invasive species that promote the settling of emergent toxins in the food-chain. Tetrodotoxin, ciguatoxin, palytoxin and cyclic imines are commonly reported in warm waters but have also caused poisoning incidents in temperate zones. There is evidence that monitoring for these toxins exclusively in bivalves is simplistic and underestimates the risk to public health, since new vectors have been reported for these toxins and as well for regulated toxins such as PSTs and DSTs. In order to avoid public health impacts, there is a need for adequate monitoring programs, a need for establishing appropriate legislation, and a need for optimizing effective methods of analysis. In this review, we will compile evidence concerning emergent marine toxins and provide data that may indicate the need to restructure the current monitoring programs of HAB.

  20. Emergent Toxins in North Atlantic Temperate Waters: A Challenge for Monitoring Programs and Legislation

    Science.gov (United States)

    Silva, Marisa; Pratheepa, Vijaya K.; Botana, Luis M.; Vasconcelos, Vitor

    2015-01-01

    Harmful Algal Blooms (HAB) are complex to manage due to their intermittent nature and their severe impact on the economy and human health. The conditions which promote HAB have not yet been fully explained, though climate change and anthropogenic intervention are pointed as significant factors. The rise of water temperature, the opening of new sea canals and the introduction of ship ballast waters all contribute to the dispersion and establishment of toxin-producing invasive species that promote the settling of emergent toxins in the food-chain. Tetrodotoxin, ciguatoxin, palytoxin and cyclic imines are commonly reported in warm waters but have also caused poisoning incidents in temperate zones. There is evidence that monitoring for these toxins exclusively in bivalves is simplistic and underestimates the risk to public health, since new vectors have been reported for these toxins and as well for regulated toxins such as PSTs and DSTs. In order to avoid public health impacts, there is a need for adequate monitoring programs, a need for establishing appropriate legislation, and a need for optimizing effective methods of analysis. In this review, we will compile evidence concerning emergent marine toxins and provide data that may indicate the need to restructure the current monitoring programs of HAB. PMID:25785464

  1. Nearshore marine benthic invertebrates moving north along the U.S. Atlantic coast

    Science.gov (United States)

    Numerous species have shifted their ranges north in response to global warming. We examined 21 years (1990-2010) of marine benthic invertebrate data from the National Coastal Assessment’s monitoring of nearshore waters along the US Atlantic coast. Data came from three bioge...

  2. Temperature profile and water depth data collected from HARRIOT LANE in the NW Atlantic (limit-40 W) from 29 December 1986 to 31 December 1986 (NODC Accession 8700074)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XTB casts in the NW Atlantic Ocean from the HARRIOT LANE. Data were collected from 29 December...

  3. Temperature profile and water depth data collected from TOWERS in the NE Atlantic (limit-180 W) from 06 June 1986 to 29 August 1986 (NODC Accession 8600378)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the TOWERS in the Northeast Atlantic Ocean, South China Sea, Philippine Sea, and...

  4. Impact of water-accommodated fractions of crude oil on Atlantic cod, Gadus morhua following chronic exposure

    International Nuclear Information System (INIS)

    Khan, R.

    2010-01-01

    This study examined the long-term effects of hydrocarbon exposure on the gonadal development of fish. Mature Atlantic cod (Gadus morhua) were exposed to low concentrations of water accommodated fractions (WAFs) of polycyclic aromatic hydrocarbons (PAHs) in an ambient flowthrough seawater system. Some PAH-exposed cod groups were depurated afterwards for 38 to 287 days. Mortality was rare, and external lesions occurred only in the PAH-exposed groups. The gonado-somatic index revealed that gonadal development was disrupted in both sexes and spawning and spermiation was delayed in the 33 depurated PAH-groups. The findings indicate that chronic exposure to WAFs in the water column may have an adverse effect on reproduction in Atlantic cod.

  5. Determination of deep water circulation in the East Atlantic Ocean by means of a box-model based evaluation of C-14 measurements and other tracer data

    International Nuclear Information System (INIS)

    Schlitzer, R.

    1984-01-01

    Radiocarbon (C-14) measurements proved to be an efficient means of determining the average, large-area deep water circulation in the Atlantic Ocean. The thesis under review explains and discusses measurements carried out in the equatorial West Atlantic and North Atlantic Ocean. The samples have been taken during mission 56 of the RS 'meteor' in spring 1981. The gas has been obtained by vacuum extraction and the measurements have been performed in proportional counter tubes, the error to be accounted for amounting to 2per mille. These measured data, together with measurements of the potential temperatures, the silicate and CO 2 concentrations, and measured data from the South-East Atlantic Ocean, have been used to calculate on the basis of a box model of the Atlantic Ocean the deep water flow from the West to the East Atlantic Ocean, the deep water circulation between the various East Atlantic basins, and the turbulent diffusion coefficients required to parameterize the deep water mixing processes. (orig./HP) [de

  6. Interocean exchange of thermocline water

    Science.gov (United States)

    Gordon, Arnold L.

    1986-04-01

    Formation of North Atlantic Deep Water (NADW) represents a transfer of upper layer water to abyssal depths at a rate of 15 to 20 × 106 m3/s. NADW spreads throughout the Atlantic Ocean and is exported to the Indian and Pacific Oceans by the Antarctic Circumpolar Current and deep western boundary currents. Naturally, there must be a compensating flow of upper layer water toward the northern North Atlantic to feed NADW production. It is proposed that this return flow is accomplished primarily within the ocean's warm water thermocline layer. In this way the main thermoclines of the ocean are linked as they participate in a thermohaline-driven global scale circulation cell associated with NADW formation. The path of the return flow of warm water is as follows: Pacific to Indian flow within the Indonesian Seas, advection across the Indian Ocean in the 10°-15°S latitude belt, southward transfer in the Mozambique Channel, entry into the South Atlantic by a branch of the Agulhas Current that does not complete the retroflection pattern, northward advection within the subtropical gyre of the South Atlantic (which on balance with the southward flux of colder North Atlantic Deep Water supports the northward oceanic heat flux characteristic of the South Atlantic), and cross-equatorial flow into the western North Atlantic. The magnitude of the return flow increases along its path as more NADW is incorporated into the upper layer of the ocean. Additionally, the water mass characteristics of the return flow are gradually altered by regional ocean-atmosphere interaction and mixing processes. Within the Indonesian seas there is evidence of strong vertical mixing across the thermocline. The cold water route, Pacific to Atlantic transport of Subantarctic water within the Drake Passage, is of secondary importance, amounting to perhaps 25% of the warm water route transport. The continuity or vigor of the warm water route is vulnerable to change not only as the thermohaline forcing in

  7. Monitoring water quality in Northwest Atlantic coastal waters using dinoflagellate cysts

    Science.gov (United States)

    Nutrient pollution is a major environmental problem in many coastal waters around the US. Determining the total input of nutrients to estuaries is a challenge. One method to evaluate nutrient input is through nutrient loading models. Another method relies upon using indicators as...

  8. What Drives the Variability of the Atlantic Water Circulation in the Arctic Ocean?

    Science.gov (United States)

    Lique, C.; Johnson, H. L.

    2016-02-01

    The Atlantic Water (AW) layer in the Arctic Basin is isolated from the atmosphere by the overlaying surface layer; yet observations of the AW pan-Arctic boundary current have revealed that the velocities in this layer exhibit significant variations on all timescales. Here, analysis of a global ocean/sea ice model hindcast, complemented by experiments performed with an idealized process model, are used to investigate what controls the variability of AW circulation, with a focus on the role of wind forcing. The AW circulation carries the imprint of wind variations, both remotely over the Nordic and Barents seas where they force variability on the AW inflow to the Arctic Basin, and locally over the Arctic Basin through the forcing of the wind-driven Beaufort gyre, which modulates and transfers the wind variability to the AW layer. Our results further suggest that understanding variability in the large amount of heat contained within the AW layer requires a better understanding of the circulation within both AW and surface layers.

  9. Determination of TBT in water and sediment samples along the Argentine Atlantic coast.

    Science.gov (United States)

    de Waisbaum, R G; Rodriguez, C; Nudelman, N Sbarbati

    2010-11-01

    Cases of imposex have been reported for some organisms living in areas of the Argentine Atlantic coast. Since this is one of the known effects of the anti-fouling agent tributyltin (TBT), quantitative determinations of organotins in samples of water and sediments collected from sites along the Argentine coast were carried out. Severe cases of imposex were first reported for two gastropod species living in the Mar del Plata area, and determinations of TBT in samples collected from this site gave extremely high values and showed a close correlation between the degree of imposex and TBT concentration. Recent investigations in the area have shown a significant decrease. Surveys were also conducted in sites that exhibit highly irregular coastal profiles to examine the relevance of physical environments. Alarming concentrations of TBT were determined in most of the sites where heavy boat traffic and/or marine activities occur, demonstrating the urgent need for regulations to avoid further input of TBT. Reports from other sites in South America reveal that this should be a subject of regional concern in order to avoid severe damage to the biodiversity of regional marine organisms.

  10. Marine parasites as biological tags in South American Atlantic waters, current status and perspectives.

    Science.gov (United States)

    Cantatore, D M P; Timi, J T

    2015-01-01

    Many marine fisheries in South American Atlantic coasts (SAAC) are threatened by overfishing and under serious risk of collapsing. The SAAC comprises a diversity of environments, possesses a complex oceanography and harbours a vast biodiversity that provide an enormous potential for using parasites as biological tags for fish stock delineation, a prerequisite for the implementation of control and management plans. Here, their use in the SAAC is reviewed. Main evidence is derived from northern Argentine waters, where fish parasite assemblages are dominated by larval helminth species that share a low specificity, long persistence and trophic transmission, parasitizing almost indiscriminately all available fish species. The advantages and constraints of such a combination of characteristics are analysed and recommendations are given for future research. Shifting the focus from fish/parasite populations to communities allows expanding the concept of biological tags from local to regional scales, providing essential information to delineate ecosystem boundaries for host communities. This new concept arose as a powerful tool to help the implementation of ecosystem-based approaches to fisheries management, the new paradigm for fisheries science. Holistic approaches, including parasites as biological tags for stock delineation will render valuable information to help insure fisheries and marine ecosystems against further depletion and collapse.

  11. Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options

    Directory of Open Access Journals (Sweden)

    Xiaobo Xue

    2016-04-01

    Full Text Available Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG emissions and aqueous nutrient releases of the whole anthropogenic municipal water cycle starting from raw water extraction to wastewater treatment and reuse/discharge for five municipal water and wastewater systems. The assessed options included conventional centralized services and four alternative options following the principles of source-separation and water fit-for-purpose. The comparative life cycle assessment identified that centralized drinking water supply coupled with blackwater energy recovery and on-site greywater treatment and reuse was the most energy- and carbon-efficient water service system evaluated, while the conventional (drinking water and sewerage centralized system ranked as the most energy- and carbon-intensive system. The electricity generated from blackwater and food residuals co-digestion was estimated to offset at least 40% of life cycle energy consumption for water/waste services. The dry composting toilet option demonstrated the lowest life cycle eutrophication potential. The nutrients in wastewater effluent are the dominating contributors for the eutrophication potential for the assessed system configurations. Among the parameters for which variability and sensitivity were evaluated, the carbon intensity of the local electricity grid and the efficiency of electricity production by the co-digestion with the energy recovery process were the most important for determining the relative global warming potential results.

  12. Influences of spawning timing, water temperature, and climatic warming on early life history phenology in western Alaska sockeye salmon

    Science.gov (United States)

    Sparks, Morgan M.; Falke, Jeffrey A.; Quinn, Thomas P.; Adkison, Milo D.; Schindler, Daniel E.; Bartz, Krista K.; Young, Daniel B.; Westley, Peter A. H.

    2018-01-01

    We applied an empirical model to predict hatching and emergence timing for 25 western Alaska sockeye salmon (Oncorhynchus nerka) populations in four lake-nursery systems to explore current patterns and potential responses of early life history phenology to warming water temperatures. Given experienced temperature regimes during development, we predicted hatching to occur in as few as 58 d to as many as 260 d depending on spawning timing and temperature. For a focal lake spawning population, our climate-lake temperature model predicted a water temperature increase of 0.7 to 1.4 °C from 2015 to 2099 during the incubation period, which translated to a 16 d to 30 d earlier hatching timing. The most extreme scenarios of warming advanced development by approximately a week earlier than historical minima and thus climatic warming may lead to only modest shifts in phenology during the early life history stage of this population. The marked variation in the predicted timing of hatching and emergence among populations in close proximity on the landscape may serve to buffer this metapopulation from climate change.

  13. African and Atlantic short-term climatic variations described from Meteosat water vapor channel

    Directory of Open Access Journals (Sweden)

    L. Picon

    1995-07-01

    Full Text Available Pluriannual series of Meteosat-2 water vapor (WV images are used to build average maps of decadal and monthly brightness temperatures in the 6.3 µm channel. This processing is applied to all the 3-hourly scenes, clear or cloudy, for July 1983 to July 1987. The ISCCP cloudiness analyses confirm that the warmest spots in the monthly WV images correspond to scenes either clear or covered with low clouds, whereas the coldest areas correspond to scenes where cloud tops above 440 hPa frequently occur. The WV statistics are then used to characterize seasonal and interannual variations of both the ITCZ (InterTropical Convergence Zone and the warm (dry areas, corresponding to subtropical subsidence. Thanks mainly to the seasonal variations, relationships between the variations in the ITCZ and in dry subtropical areas can be studied. It is shown that, for the Meteosat sector, a wetter subtropical high troposphere is associated with an enhanced activity of the ITCZ, and vice versa. For this area where the north-south assymetry is large, the negative water vapor feedback previously proposed seems not to occur.

  14. Freshening of Antarctic Intermediate Water in the South Atlantic Ocean in 2005–2014

    Directory of Open Access Journals (Sweden)

    W. Yao

    2017-07-01

    Full Text Available Basin-scale freshening of Antarctic Intermediate Water (AAIW is reported to have occurred in the South Atlantic Ocean during the period from 2005 to 2014, as shown by the gridded monthly means of the Array for Real-time Geostrophic Oceanography (Argo data. This phenomenon was also revealed by two repeated transects along a section at 30° S, performed during the World Ocean Circulation Experiment Hydrographic Program. Freshening of the AAIW was compensated for by a salinity increase of thermocline water, indicating a hydrological cycle intensification. This was supported by the precipitation-minus-evaporation change in the Southern Hemisphere from 2000 to 2014. Freshwater input from atmosphere to ocean surface increased in the subpolar high-precipitation region and vice versa in the subtropical high-evaporation region. Against the background of hydrological cycle changes, a decrease in the transport of Agulhas Leakage (AL, which was revealed by the simulated velocity field, was proposed to be a contributor to the associated freshening of AAIW. Further calculation showed that such a decrease could account for approximately 53 % of the observed freshening (mean salinity reduction of about 0.012 over the AAIW layer. The estimated variability of AL was inferred from a weakening of wind stress over the South Indian Ocean since the beginning of the 2000s, which would facilitate freshwater input from the source region. The mechanical analysis of wind data here was qualitative, but it is contended that this study would be helpful to validate and test predictably coupled sea–air model simulations.

  15. Freshening of Antarctic Intermediate Water in the South Atlantic Ocean in 2005-2014

    Science.gov (United States)

    Yao, Wenjun; Shi, Jiuxin; Zhao, Xiaolong

    2017-07-01

    Basin-scale freshening of Antarctic Intermediate Water (AAIW) is reported to have occurred in the South Atlantic Ocean during the period from 2005 to 2014, as shown by the gridded monthly means of the Array for Real-time Geostrophic Oceanography (Argo) data. This phenomenon was also revealed by two repeated transects along a section at 30° S, performed during the World Ocean Circulation Experiment Hydrographic Program. Freshening of the AAIW was compensated for by a salinity increase of thermocline water, indicating a hydrological cycle intensification. This was supported by the precipitation-minus-evaporation change in the Southern Hemisphere from 2000 to 2014. Freshwater input from atmosphere to ocean surface increased in the subpolar high-precipitation region and vice versa in the subtropical high-evaporation region. Against the background of hydrological cycle changes, a decrease in the transport of Agulhas Leakage (AL), which was revealed by the simulated velocity field, was proposed to be a contributor to the associated freshening of AAIW. Further calculation showed that such a decrease could account for approximately 53 % of the observed freshening (mean salinity reduction of about 0.012 over the AAIW layer). The estimated variability of AL was inferred from a weakening of wind stress over the South Indian Ocean since the beginning of the 2000s, which would facilitate freshwater input from the source region. The mechanical analysis of wind data here was qualitative, but it is contended that this study would be helpful to validate and test predictably coupled sea-air model simulations.

  16. The role of deep-water sedimentary processes in shaping a continental margin: The Northwest Atlantic

    Science.gov (United States)

    Mosher, David C.; Campbell, D.C.; Gardner, J.V.; Piper, D.J.W.; Chaytor, Jason; Rebesco, M.

    2017-01-01

    The tectonic history of a margin dictates its general shape; however, its geomorphology is generally transformed by deep-sea sedimentary processes. The objective of this study is to show the influences of turbidity currents, contour currents and sediment mass failures on the geomorphology of the deep-water northwestern Atlantic margin (NWAM) between Blake Ridge and Hudson Trough, spanning about 32° of latitude and the shelf edge to the abyssal plain. This assessment is based on new multibeam echosounder data, global bathymetric models and sub-surface geophysical information.The deep-water NWAM is divided into four broad geomorphologic classifications based on their bathymetric shape: graded, above-grade, stepped and out-of-grade. These shapes were created as a function of the balance between sediment accumulation and removal that in turn were related to sedimentary processes and slope-accommodation. This descriptive method of classifying continental margins, while being non-interpretative, is more informative than the conventional continental shelf, slope and rise classification, and better facilitates interpretation concerning dominant sedimentary processes.Areas of the margin dominated by turbidity currents and slope by-pass developed graded slopes. If sediments did not by-pass the slope due to accommodation then an above grade or stepped slope resulted. Geostrophic currents created sedimentary bodies of a variety of forms and positions along the NWAM. Detached drifts form linear, above-grade slopes along their crests from the shelf edge to the deep basin. Plastered drifts formed stepped slope profiles. Sediment mass failure has had a variety of consequences on the margin morphology; large mass-failures created out-of-grade profiles, whereas smaller mass failures tended to remain on the slope and formed above-grade profiles at trough-mouth fans, or nearly graded profiles, such as offshore Cape Fear.

  17. Spatial distribution of water erosion risk in a watershed with eucalyptus and Atlantic Forest

    Directory of Open Access Journals (Sweden)

    Junior Cesar Avanzi

    2013-10-01

    Full Text Available The process of water erosion occurs in watersheds throughout the world and it is strongly affected by anthropogenic influences. Thus, the knowledge of these processes is extremely necessary for planning of conservation efforts. This study was performed in an experimental forested watershed in order to predict the average potential annual soil loss by water erosion using the Universal Soil Loss Equation (USLE and a Geographic Information System (GIS, and then compared with soil loss tolerance. All the USLE factors were generated in a distributed approach employing a GIS tool. The layers were multiplied in the GIS framework in order to predict soil erosion rates. Results showed that the average soil loss was 6.2 Mg ha-1 yr-1. Relative to soil loss tolerance, 83% of the area had an erosion rate lesser than the tolerable value. According to soil loss classes, 49% of the watershed had erosion less than 2.5 Mg ha-1 yr-1. However, about 8.7% of the watershed had erosion rates greater than 15 Mg ha-1 yr-1, being mainly related to Plinthosol soil class and roads, thus requiring special attention for the improvement of sustainable management practices for such areas. Eucalyptus cultivation was found to have soil loss greater than Atlantic Forest. Thus, an effort should be made to bring the erosion rates closer to the native forest. Implementation of the USLE model in a GIS framework was found to be a simple and useful tool for predicting the spatial variation of soil erosion risk and identifying critical areas for conservation efforts.

  18. Life cycle analysis of distributed concentrating solar combined heat and power: economics, global warming potential and water

    Science.gov (United States)

    Norwood, Zack; Kammen, Daniel

    2012-12-01

    We report on life cycle assessment (LCA) of the economics, global warming potential and water (both for desalination and water use in operation) for a distributed concentrating solar combined heat and power (DCS-CHP) system. Detailed simulation of system performance across 1020 sites in the US combined with a sensible cost allocation scheme informs this LCA. We forecast a levelized cost of 0.25 kWh-1 electricity and 0.03 kWh-1 thermal, for a system with a life cycle global warming potential of ˜80 gCO2eq kWh-1 of electricity and ˜10 gCO2eq kWh-1 thermal, sited in Oakland, California. On the basis of the economics shown for air cooling, and the fact that any combined heat and power system reduces the need for cooling while at the same time boosting the overall solar efficiency of the system, DCS-CHP compares favorably to other electric power generation systems in terms of minimization of water use in the maintenance and operation of the plant. The outlook for water desalination coupled with distributed concentrating solar combined heat and power is less favorable. At a projected cost of 1.40 m-3, water desalination with DCS-CHP would be economical and practical only in areas where water is very scarce or moderately expensive, primarily available through the informal sector, and where contaminated or salt water is easily available as feed-water. It is also interesting to note that 0.40-1.90 m-3 is the range of water prices in the developed world, so DCS-CHP desalination systems could also be an economical solution there under some conditions.

  19. Life cycle analysis of distributed concentrating solar combined heat and power: economics, global warming potential and water

    International Nuclear Information System (INIS)

    Norwood, Zack; Kammen, Daniel

    2012-01-01

    We report on life cycle assessment (LCA) of the economics, global warming potential and water (both for desalination and water use in operation) for a distributed concentrating solar combined heat and power (DCS-CHP) system. Detailed simulation of system performance across 1020 sites in the US combined with a sensible cost allocation scheme informs this LCA. We forecast a levelized cost of $0.25 kWh −1 electricity and $0.03 kWh −1 thermal, for a system with a life cycle global warming potential of ∼80 gCO 2 eq kWh −1 of electricity and ∼10 gCO 2 eq kWh −1 thermal, sited in Oakland, California. On the basis of the economics shown for air cooling, and the fact that any combined heat and power system reduces the need for cooling while at the same time boosting the overall solar efficiency of the system, DCS-CHP compares favorably to other electric power generation systems in terms of minimization of water use in the maintenance and operation of the plant. The outlook for water desalination coupled with distributed concentrating solar combined heat and power is less favorable. At a projected cost of $1.40 m −3 , water desalination with DCS-CHP would be economical and practical only in areas where water is very scarce or moderately expensive, primarily available through the informal sector, and where contaminated or salt water is easily available as feed-water. It is also interesting to note that $0.40–$1.90 m −3 is the range of water prices in the developed world, so DCS-CHP desalination systems could also be an economical solution there under some conditions. (letter)

  20. How does ocean ventilation change under global warming?

    Directory of Open Access Journals (Sweden)

    A. Gnanadesikan

    2007-01-01

    Full Text Available Since the upper ocean takes up much of the heat added to the earth system by anthropogenic global warming, one would expect that global warming would lead to an increase in stratification and a decrease in the ventilation of the ocean interior. However, multiple simulations in global coupled climate models using an ideal age tracer which is set to zero in the mixed layer and ages at 1 yr/yr outside this layer show that the intermediate depths in the low latitudes, Northwest Atlantic, and parts of the Arctic Ocean become younger under global warming. This paper reconciles these apparently contradictory trends, showing that the decreases result from changes in the relative contributions of old deep waters and younger surface waters. Implications for the tropical oxygen minimum zones, which play a critical role in global biogeochemical cycling are considered in detail.

  1. North Atlantic near-surface salinity contrasts and intra-basin water vapor transfer

    Science.gov (United States)

    Reagan, J. R.; Seidov, D.; Boyer, T.

    2017-12-01

    The geographic distribution of near-surface salinity (NSS) in the North Atlantic is characterized by a very salty (>37) subtropical region contrasting with a much fresher (NSS. Additional results and potential implications will be presented and discussed.

  2. Biological processes in the water column of the South Atlantic bight

    Energy Technology Data Exchange (ETDEWEB)

    Paffenhoefer, G.A.; Yoder, J.A.

    1980-01-31

    Progress is reported on research conducted during 1979 on the biological oceanography of the South Atlantic Bight. The presentation consists of a number of published articles and abstracts of oral presentations. (ACR)

  3. Abrupt pre-Bølling-Allerød warming and circulation changes in the deep ocean.

    Science.gov (United States)

    Thiagarajan, Nivedita; Subhas, Adam V; Southon, John R; Eiler, John M; Adkins, Jess F

    2014-07-03

    Several large and rapid changes in atmospheric temperature and the partial pressure of carbon dioxide in the atmosphere--probably linked to changes in deep ocean circulation--occurred during the last deglaciation. The abrupt temperature rise in the Northern Hemisphere and the restart of the Atlantic meridional overturning circulation at the start of the Bølling-Allerød interstadial, 14,700 years ago, are among the most dramatic deglacial events, but their underlying physical causes are not known. Here we show that the release of heat from warm waters in the deep North Atlantic Ocean probably triggered the Bølling-Allerød warming and reinvigoration of the Atlantic meridional overturning circulation. Our results are based on coupled radiocarbon and uranium-series dates, along with clumped isotope temperature estimates, from water column profiles of fossil deep-sea corals in a limited area of the western North Atlantic. We find that during Heinrich stadial 1 (the cool period immediately before the Bølling-Allerød interstadial), the deep ocean was about three degrees Celsius warmer than shallower waters above. This reversal of the ocean's usual thermal stratification pre-dates the Bølling-Allerød warming and must have been associated with increased salinity at depth to preserve the static stability of the water column. The depleted radiocarbon content of the warm and salty water mass implies a long-term disconnect from rapid surface exchanges, and, although uncertainties remain, is most consistent with a Southern Ocean source. The Heinrich stadial 1 ocean profile is distinct from the modern water column, that for the Last Glacial Maximum and that for the Younger Dryas, suggesting that the patterns we observe are a unique feature of the deglacial climate system. Our observations indicate that the deep ocean influenced dramatic Northern Hemisphere warming by storing heat at depth that preconditioned the system for a subsequent abrupt overturning event during the

  4. Biofilm Composition and Threshold Concentration for Growth of Legionella pneumophila on Surfaces Exposed to Flowing Warm Tap Water without Disinfectant.

    Science.gov (United States)

    van der Kooij, Dick; Bakker, Geo L; Italiaander, Ronald; Veenendaal, Harm R; Wullings, Bart A

    2017-03-01

    Legionella pneumophila in potable water installations poses a potential health risk, but quantitative information about its replication in biofilms in relation to water quality is scarce. Therefore, biofilm formation on the surfaces of glass and chlorinated polyvinyl chloride (CPVC) in contact with tap water at 34 to 39°C was investigated under controlled hydraulic conditions in a model system inoculated with biofilm-grown L. pneumophila The biofilm on glass (average steady-state concentration, 23 ± 9 pg ATP cm -2 ) exposed to treated aerobic groundwater (0.3 mg C liter -1 ; 1 μg assimilable organic carbon [AOC] liter -1 ) did not support growth of the organism, which also disappeared from the biofilm on CPVC (49 ± 9 pg ATP cm -2 ) after initial growth. L. pneumophila attained a level of 4.3 log CFU cm -2 in the biofilms on glass (1,055 ± 225 pg ATP cm -2 ) and CPVC (2,755 ± 460 pg ATP cm -2 ) exposed to treated anaerobic groundwater (7.9 mg C liter -1 ; 10 μg AOC liter -1 ). An elevated biofilm concentration and growth of L. pneumophila were also observed with tap water from the laboratory. The Betaproteobacteria Piscinibacter and Methyloversatilis and amoeba-resisting Alphaproteobacteria predominated in the clones and isolates retrieved from the biofilms. In the biofilms, the Legionella colony count correlated significantly with the total cell count (TCC), heterotrophic plate count, ATP concentration, and presence of Vermamoeba vermiformis This amoeba was rarely detected at biofilm concentrations of water-associated disease outbreaks reported in the United States. The organism proliferates in biofilms on surfaces exposed to warm water in engineered freshwater installations. An investigation with a test system supplied with different types of warm drinking water without disinfectant under controlled hydraulic conditions showed that treated aerobic groundwater (0.3 mg liter -1 of organic carbon) induced a low biofilm concentration that supported no or very

  5. Asymmetric response of tropical cyclone activity to global warming over the North Atlantic and western North Pacific from CMIP5 model projections.

    Science.gov (United States)

    Park, Doo-Sun R; Ho, Chang-Hoi; Chan, Johnny C L; Ha, Kyung-Ja; Kim, Hyeong-Seog; Kim, Jinwon; Kim, Joo-Hong

    2017-01-30

    Recent improvements in the theoretical understanding of the relationship between tropical cyclones (TCs) and their large-scale environments have resulted in significant improvements in the skill for forecasting TC activity at daily and seasonal time-scales. However, future changes in TC activity under a warmer climate remain uncertain, particularly in terms of TC genesis locations and subsequent pathways. Applying a track-pattern-based statistical model to 22 Coupled Model Intercomparison Project Phase 5 (CMIP5) model runs for the historical period and the future period corresponding to the Representative Concentration Pathway 8.5 emissions scenarios, this study shows that in future climate conditions, TC passage frequency will decrease over the North Atlantic, particularly in the Gulf of Mexico, but will increase over the western North Pacific, especially that hits Korea and Japan. Unlike previous studies based on fine-resolution models, an ensemble mean of CMIP5 models projects an increase in TC activity in the western North Pacific, which is owing to enhanced subtropical deep convection and favorable dynamic conditions therein in conjunction with the expansion of the tropics and vice versa for the North Atlantic. Our results suggest that North America will experience less TC landfalls, while northeast Asia will experience more TCs than in the present-day climate.

  6. Marine ecosystem response to the Atlantic Multidecadal Oscillation.

    Directory of Open Access Journals (Sweden)

    Martin Edwards

    Full Text Available Against the backdrop of warming of the Northern Hemisphere it has recently been acknowledged that North Atlantic temperature changes undergo considerable variability over multidecadal periods. The leading component of natural low-frequency temperature variability has been termed the Atlantic Multidecadal Oscillation (AMO. Presently, correlative studies on the biological impact of the AMO on marine ecosystems over the duration of a whole AMO cycle (∼60 years is largely unknown due to the rarity of continuously sustained biological observations at the same time period. To test whether there is multidecadal cyclic behaviour in biological time-series in the North Atlantic we used one of the world's longest continuously sustained marine biological time-series in oceanic waters, long-term fisheries data and historical records over the last century and beyond. Our findings suggest that the AMO is far from a trivial presence against the backdrop of continued temperature warming in the North Atlantic and accounts for the second most important macro-trend in North Atlantic plankton records; responsible for habitat switching (abrupt ecosystem/regime shifts over multidecadal scales and influences the fortunes of various fisheries over many centuries.

  7. Starting a DNA barcode reference library for shallow water polychaetes from the southern European Atlantic coast.

    Science.gov (United States)

    Lobo, Jorge; Teixeira, Marcos A L; Borges, Luisa M S; Ferreira, Maria S G; Hollatz, Claudia; Gomes, Pedro T; Sousa, Ronaldo; Ravara, Ascensão; Costa, Maria H; Costa, Filipe O

    2016-01-01

    Annelid polychaetes have been seldom the focus of dedicated DNA barcoding studies, despite their ecological relevance and often dominance, particularly in soft-bottom estuarine and coastal marine ecosystems. Here, we report the first assessment of the performance of DNA barcodes in the discrimination of shallow water polychaete species from the southern European Atlantic coast, focusing on specimens collected in estuaries and coastal ecosystems of Portugal. We analysed cytochrome oxidase I DNA barcodes (COI-5P) from 164 specimens, which were assigned to 51 morphospecies. To our data set from Portugal, we added available published sequences selected from the same species, genus or family, to inspect for taxonomic congruence among studies and collection location. The final data set comprised 290 specimens and 79 morphospecies, which generated 99 Barcode Index Numbers (BINs) within Barcode of Life Data Systems (BOLD). Among these, 22 BINs were singletons, 47 other BINs were concordant, confirming the initial identification based on morphological characters, and 30 were discordant, most of which consisted on multiple BINs found for the same morphospecies. Some of the most prominent cases in the latter category include Hediste diversicolor (O.F. Müller, 1776) (7), Eulalia viridis (Linnaeus, 1767) (2) and Owenia fusiformis (delle Chiaje, 1844) (5), all of them reported from Portugal and frequently used in ecological studies as environmental quality indicators. Our results for these species showed discordance between molecular lineages and morphospecies, or added additional relatively divergent lineages. The potential inaccuracies in environmental assessments, where underpinning polychaete species diversity is poorly resolved or clarified, demand additional and extensive investigation of the DNA barcode diversity in this group, in parallel with alpha taxonomy efforts. © 2015 John Wiley & Sons Ltd.

  8. Growth Decline Linked to Warming-Induced Water Limitation in Hemi-Boreal Forests

    OpenAIRE

    Wu, Xiuchen; Liu, Hongyan; Guo, Dali; Anenkhonov, Oleg A.; Badmaeva, Natalya K.; Sandanov, Denis V.

    2012-01-01

    Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal fore...

  9. Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model

    OpenAIRE

    A. Gnanadesikan; J. P. Dunne; J. John

    2012-01-01

    Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1) shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., su...

  10. Cumulative impoundment evaporation in water resource management within the mid-Atlantic: A case study in Virginia

    Science.gov (United States)

    Scott, D.; Burgholzer, R.; Kleiner, J.; Brogan, C. O.; Julson, C.; Withers, E.

    2017-12-01

    Across the eastern United States, successful management of water resources to satisfy the competing demands for human consumption, industry, agriculture, and ecosystems requires both water quality and water quantity considerations. Over the last 2 decades, low streamflows during dry summers have increased scrutiny on water supply withdrawals. Within Virginia, a statewide hydrologic model provides quantitative assessments on impacts from proposed water withdrawals to downstream river flow. Currently, evaporative losses are only accounted for from the large reservoirs. In this study, we sought to provide a baseline estimate for the cumulative evaporation from impoundments across all of the major river basins in Virginia. Virginia provides an ideal case study for the competing water demands in the mid-Atlantic region given the unique tracking of water withdrawals throughout the river corridor. In the over 73,000 Virginia impoundments, the cumulative annual impoundment evaporation was 706 MGD, or 49% of the permitted water withdrawal. The largest reservoirs (>100 acres) represented over 400 MGD, and 136 MGD for the smaller impoundments (water loss (evaporation + demand), with some areas where impoundment evaporation was greater than human water demand. Seasonally, our results suggest that cumulative impoundment evaporation in some watersheds greatly impacts streamflow during low flow periods. Our results demonstrate that future water supply planning will require not only understanding evaporation within large reservoirs, but also the thousands of small impoundments across the landscape.

  11. Trophic Ecology and Movement Patters of Tiger Sharks (Galeocerdo Cuvier) off the Western North Atlantic Coastal and Continental Shelf Waters

    Science.gov (United States)

    Sancho, G.; Edman, R.; Frazier, B.; Bubley, W.

    2016-02-01

    Understanding the trophic dynamics and habitat utilization of apex predators is central to inferring their influence on different marine landscapes and to help design effective management plans for these animals. Tiger sharks (Galeocerdo cuvier) are abundant in shelf and offshore Gulf Stream waters of the western North Atlantic Ocean, and based on movements from individuals captured in Florida and Bahamas, seem to avoid coastal and shelf waters off South Carolina and Georgia. This contradicts reports of tiger sharks regularly being caught nearshore by anglers in these states, indicating that separate sub-populations may exist in the western North Atlantic. In the present study we captured Tiger Sharks in coastal waters off South Carolina in 2014 and 2015 in order to describe their movement patterns through acoustic and satellite tagging, and trophic dynamics through stable isotope analyses. Movement data show that these tiger sharks repeatedly visit particular inshore areas and mainly travel over the continental shelf, but rarely venture offshore beyond the continental shelf edge. Ongoing C and N stable isotope analyses of muscle, blood and skin tissues from adult and juvenile tiger sharks, as well as from potential prey species and primary producers, will help determine if their diets are based on inshore, shelf or offshore based food webs. Tiger sharks exploiting nearshore environments and shelf waters have much higher probabilities of interacting with humans than individuals occupying far offshore Gulf Stream habitats.

  12. Cost, energy, global warming, eutrophication and local human health impacts of community water and sanitation service options.

    Science.gov (United States)

    Schoen, Mary E; Xue, Xiaobo; Wood, Alison; Hawkins, Troy R; Garland, Jay; Ashbolt, Nicholas J

    2017-02-01

    We compared water and sanitation system options for a coastal community across selected sustainability metrics, including environmental impact (i.e., life cycle eutrophication potential, energy consumption, and global warming potential), equivalent annual cost, and local human health impact. We computed normalized metric scores, which we used to discuss the options' strengths and weaknesses, and conducted sensitivity analysis of the scores to changes in variable and uncertain input parameters. The alternative systems, which combined centralized drinking water with sanitation services based on the concepts of energy and nutrient recovery as well as on-site water reuse, had reduced environmental and local human health impacts and costs than the conventional, centralized option. Of the selected sustainability metrics, the greatest advantages of the alternative community water systems (compared to the conventional system) were in terms of local human health impact and eutrophication potential, despite large, outstanding uncertainties. Of the alternative options, the systems with on-site water reuse and energy recovery technologies had the least local human health impact; however, the cost of these options was highly variable and the energy consumption was comparable to on-site alternatives without water reuse or energy recovery, due to on-site reuse treatment. Future work should aim to reduce the uncertainty in the energy recovery process and explore the health risks associated with less costly, on-site water treatment options. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Water- and plant-mediated responses of ecosystem carbon fluxes to warming and nitrogen addition on the Songnen grassland in northeast China.

    Directory of Open Access Journals (Sweden)

    Li Jiang

    Full Text Available Understanding how grasslands are affected by a long-term increase in temperature is crucial to predict the future impact of global climate change on terrestrial ecosystems. Additionally, it is not clear how the effects of global warming on grassland productivity are going to be altered by increased N deposition and N addition.In-situ canopy CO(2 exchange rates were measured in a meadow steppe subjected to 4-year warming and nitrogen addition treatments. Warming treatment reduced net ecosystem CO(2 exchange (NEE and increased ecosystem respiration (ER; but had no significant impacts on gross ecosystem productivity (GEP. N addition increased NEE, ER and GEP. However, there were no significant interactions between N addition and warming. The variation of NEE during the four experimental years was correlated with soil water content, particularly during early spring, suggesting that water availability is a primary driver of carbon fluxes in the studied semi-arid grassland.Ecosystem carbon fluxes in grassland ecosystems are sensitive to warming and N addition. In the studied water-limited grassland, both warming and N addition influence ecosystem carbon fluxes by affecting water availability, which is the primary driver in many arid and semiarid ecosystems. It remains unknown to what extent the long-term N addition would affect the turn-over of soil organic matter and the C sink size of this grassland.

  14. TOPEX/El Nino Watch - El Nino Warm Water Pool Returns to Near Normal State, Mar, 14, 1998

    Science.gov (United States)

    1998-01-01

    This image of the Pacific Ocean was produced using sea surface height measurements taken by the U.S.-French TOPEX/Poseidon satellite. The image shows sea surface height relative to normal ocean conditions on Mar. 14, 1998 and sea surface height is an indicator of the heat content of the ocean. The image shows that the sea surface height along the central equatorial Pacific has returned to a near normal state. Oceanographers indicate this is a classic pattern, typical of a mature El Nino condition. Remnants of the El Nino warm water pool, shown in red and white, are situated to the north and south of the equator. These sea surface height measurements have provided scientists with a detailed view of how the 1997-98 El Nino's warm pool behaves because the TOPEX/Poseidon satellite measures the changing sea surface height with unprecedented precision. In this image, the white and red areas indicate unusual patterns of heat storage; in the white areas, the sea surface is between 14 and 32 centimeters (6 to 13 inches) above normal; in the red areas, it's about 10 centimeters (4 inches) above normal. The green areas indicate normal conditions, while purple (the western Pacific) means at least 18 centimeters (7 inches) below normal sea level. The El Nino phenomenon is thought to be triggered when the steady westward blowing trade winds weaken and even reverse direction. This change in the winds allows a large mass of warm water (the red and white area) that is normally located near Australia to move eastward along the equator until it reaches the coast of South America. The displacement of so much warm water affects evaporation, where rain clouds form and, consequently, alters the typical atmospheric jet stream patterns around the world. Using satellite imagery, buoy and ship data, and a forecasting model of the ocean-atmosphere system, the National Oceanic and Atmospheric Administration, (NOAA), has continued to issue an advisory indicating the so-called El Nino weather

  15. Geochemical analysis of atlantic rim water, carbon county, wyoming: New applications for characterizing coalbed natural gas reservoirs

    Science.gov (United States)

    McLaughlin, J.F.; Frost, C.D.; Sharma, Shruti

    2011-01-01

    Coalbed natural gas (CBNG) production typically requires the extraction of large volumes of water from target formations, thereby influencing any associated reservoir systems. We describe isotopic tracers that provide immediate data on the presence or absence of biogenic natural gas and the identify methane-containing reservoirs are hydrologically confined. Isotopes of dissolved inorganic carbon and strontium, along with water quality data, were used to characterize the CBNG reservoirs and hydrogeologic systems of Wyoming's Atlantic Rim. Water was analyzed from a stream, springs, and CBNG wells. Strontium isotopic composition and major ion geochemistry identify two groups of surface water samples. Muddy Creek and Mesaverde Group spring samples are Ca-Mg-S04-type water with higher 87Sr/86Sr, reflecting relatively young groundwater recharged from precipitation in the Sierra Madre. Groundwaters emitted from the Lewis Shale springs are Na-HCO3-type waters with lower 87Sr/86Sr, reflecting sulfate reduction and more extensive water-rock interaction. To distinguish coalbed waters, methanogenically enriched ??13CDIC wasused from other natural waters. Enriched ??13CDIC, between -3.6 and +13.3???, identified spring water that likely originates from Mesaverde coalbed reservoirs. Strongly positive ??13CDIC, between +12.6 and +22.8???, identified those coalbed reservoirs that are confined, whereas lower ??13CDIC, between +0.0 and +9.9???, identified wells within unconfined reservoir systems. Copyright ?? 2011. The American Association of Petroleum Geologists. All rights reserved.

  16. Distribution of a pelagic tunicate, Salpa fusiformis in warm surface current of the eastern Korean waters and its impingement on cooling water intakes of Uljin nuclear power plant.

    Science.gov (United States)

    Chae, Jinho; Choi, Hyun Woo; Lee, Woo Jin; Kim, Dongsung; Lee, Jae Hac

    2008-07-01

    Impingement of a large amount of gelatinous plankton, Salpa fusiformis on the seawater intake system-screens in a nuclear power plant at Uljin was firstly recorded on 18th June 2003. Whole amount of the clogged animals was estimated were presumptively at 295 tons and the shortage of cooling seawater supply by the animal clogging caused 38% of decrease in generation capability of the power plant. Zooplankton collection with a multiple towing net during the day and at night from 5 to 6 June 2003 included various gelatinous zooplanktons known to be warm water species such as salps and siphonophores. Comparatively larger species, Salpa fusiformis occupied 25.4% in individual density among the gelatinous plankton and showed surface distribution in the depth shallower than thermocline, performing little diel vertical migration. Temperature, salinity and satellite data also showed warm surface current predominated over the southern coastal region near the power plant in June. The results suggested that warm surface current occasionally extended into the neritic region may transfer S. fusiformis, to the waters off the power plant. The environmental factors and their relation to ecobiology of the large quantity of salpa population that are being sucked into the intake channel of the power plant are discussed.

  17. A cascade of warming impacts brings bluefin tuna to Greenland waters

    DEFF Research Database (Denmark)

    MacKenzie, Brian; Payne, Mark; Boje, Jesper

    Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predator-prey dynamics in food-webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species...... since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species into the region. We conclude that a cascade of climate change impacts...

  18. Variability in warm-season atmospheric circulation and precipitation patterns over subtropical South America: relationships between the South Atlantic convergence zone and large-scale organized convection over the La Plata basin

    Science.gov (United States)

    Mattingly, Kyle S.; Mote, Thomas L.

    2017-01-01

    Warm-season precipitation variability over subtropical South America is characterized by an inverse relationship between the South Atlantic convergence zone (SACZ) and precipitation over the central and western La Plata basin of southeastern South America. This study extends the analysis of this "South American Seesaw" precipitation dipole to relationships between the SACZ and large, long-lived mesoscale convective systems (LLCSs) over the La Plata basin. By classifying SACZ events into distinct continental and oceanic categories and building a logistic regression model that relates LLCS activity across the region to continental and oceanic SACZ precipitation, a detailed account of spatial variability in the out-of-phase coupling between the SACZ and large-scale organized convection over the La Plata basin is provided. Enhanced precipitation in the continental SACZ is found to result in increased LLCS activity over northern, northeastern, and western sections of the La Plata basin, in association with poleward atmospheric moisture flux from the Amazon basin toward these regions, and a decrease in the probability of LLCS occurrence over the southeastern La Plata basin. Increased oceanic SACZ precipitation, however, was strongly related to reduced atmospheric moisture and decreased probability of LLCS occurrence over nearly the entire La Plata basin. These results suggest that continental SACZ activity and large-scale organized convection over the northern and eastern sections of the La Plata basin are closely tied to atmospheric moisture transport from the Amazon basin, while the warm coastal Brazil Current may also play an important role as an evaporative moisture source for LLCSs over the central and western La Plata basin.

  19. Pronounced subsurface cooling of North Atlantic waters off Northwest Africa during Dansgaard-Oeschger interstadials

    NARCIS (Netherlands)

    Kim, J.H.; Romero, O.E.; Lohmann, G.; Donner, B.; Laepple, T.; Haam, E.; Sinninghe Damsté, J.S.

    2012-01-01

    Millennial-scale Atlantic meridional overturning circulation (AMOC) variability has often been invoked to explain the Dansgaard-Oeschger (DO) events. However, the underlying causes responsible for millennial-scale AMOC variability are still debated. High-resolution U-37(K)' and TEX86H temperature

  20. Rapid acidification of mode and intermediate waters in the southwestern Atlantic Ocean

    NARCIS (Netherlands)

    Salt, L.A.; van Heuven, S.M.A.C.; Claus, M.E.; Jones, E.M.; de Baar, H.J.W.

    2015-01-01

    Observations along the southwestern Atlantic WOCE A17 line made during the Dutch GEOTRACESNL programme (2010-2011) were compared with historical data from 1994 to quantify the changes in the anthropogenic component of the total pool of dissolved inorganic carbon (Delta C-ant). Application of the

  1. Variation in some quality attributes of Atlantic salmon fillets from aquaculture related to geographic origin and water temperature

    DEFF Research Database (Denmark)

    Johansson, Gine Ørnholt; Frosch, Stina; Jørgensen, Bo Munk

    2017-01-01

    an efficient use of the information gathered in the different links of the value chain, a deeper knowledge of the correlations between the various quality attributes and factors like the geographical origin of the salmon, the company and the water temperature of the fish farm, is needed. In the present study......It is well know that factors like fat content and texture affect the yield when making products from Atlantic salmon (Salmo salar L.). The relation between these factors and other quality attributes like water holding capacity and protein content, however, has received limited attention. To enable...... a multivariate approach was taken to investigate the variation in some quality parameters (fat, protein, texture, water holding capacity, weight) amongst salmon samples (n = 136) from Norwegian aquaculture in order to establish which parameters were accounting for most of the variation seen in relation...

  2. Improving Conservation of Florida Manatees ( Trichechus manatus latirostris): Conceptualization and Contributions Toward a Regional Warm-Water Network Management Strategy for Sustainable Winter Habitat

    Science.gov (United States)

    Flamm, Richard Owen; Reynolds, John Elliot; Harmak, Craig

    2013-01-01

    We used southwestern Florida as a case study to lay the groundwork for an intended and organized decision-making process for managing warm-water habitat needed by endangered manatees to survive winters in Florida. Scientists and managers have prioritized (a) projecting how the network of warm-water sites will change over the next 50 years as warmed industrial discharges may expire and as flows of natural springs are reduced through redirection of water for human uses, and (b) mitigating such changes to prevent undue consequences to manatees. Given the complexities introduced by manatee ecology; agency organizational structure; shifting public demands; fluctuating resource availability; and managing within interacting cultural, social, political, and environmental contexts, it was clear that a structured decision process was needed. To help promote such a process, we collected information relevant to future decisions including maps of known and suspected warm-water sites and prototyped a characterization of sites and networks. We propose steps that would lead to models that might serve as core tools in manatee/warm-water decision-making, and we summarized topics relevant for informed decision-making (e.g., manatee spatial cognition, risk of cold-stress morbidity and mortality, and human dimensions). A major impetus behind this effort is to ensure proactively that robust modeling tools are available well in advance of the anticipated need for a critical management decision.

  3. Formation of well-mixed warm water column in central Bohai Sea during summer: Role of high-frequency atmospheric forcing

    Science.gov (United States)

    Ma, Weiwei; Wan, Xiuquan; Wang, Zhankun; Liu, Yulong; Wan, Kai

    2017-12-01

    The influence of high-frequency atmospheric forcing on the formation of a well-mixed summer warm water column in the central Bohai Sea is investigated comparing model simulations driven by daily surface forcing and those using monthly forcing data. In the absence of high-frequency atmospheric forcing, numerical simulations have repeatedly failed to reproduce this vertically uniform column of warm water measured over the past 35 years. However, high-frequency surface forcing is found to strongly influence the structure and distribution of the well-mixed warm water column, and simulations are in good agreement with observations. Results show that high frequency forcing enhances vertical mixing over the central bank, intensifies downward heat transport, and homogenizes the water column to form the Bohai central warm column. Evidence presented shows that high frequency forcing plays a dominant role in the formation of the well-mixed warm water column in summer, even without the effects of tidal and surface wave mixing. The present study thus provides a practical and rational way of further improving the performance of oceanic simulations in the Bohai Sea and can be used to adjust parameterization schemes of ocean models.

  4. Fertilisation and hatching success of Atlantic cod (Gadus morhua) eggs when exposed to various concentrations of produced water

    International Nuclear Information System (INIS)

    Wong, D.; Lyons, M.; Burridge, L.; Lee, K.

    2010-01-01

    This study investigated the fertilization and hatching success of Atlantic cod (Gadus morhua) eggs that were exposed to various dilutions of produced water from a natural gas production platform. A control group of eggs was fertilized in sea water without any produced water. Another set of eggs were fertilized in sea water with 4 different concentrations of produced water and held their respective concentrations for 24 hours to evaluate the success of the fertilization. Viable fertilized eggs were transferred to 96 well plates containing fresh sea water and incubated in the dark at approximately 6 degrees C until hatch. Eggs began hatching about 14 days after fertilization (DPF), peaked at about 17 DPF, then finished hatching by 21 DPF. Analysis of PAH content in the diluted produced water showed that at 0.32 percent, 1.08 percent and 3.6 percent concentrations, the fertilization success was greater than or equal to that of the control group. However, for the 12 percent concentration, there were no viable fertilized eggs present after the 24 hour period. Survivability of eggs during sea water incubation was similar for the 0 percent, 0.32 percent and 1.08 percent treatment groups, but egg mortality increased for the 3.60 percent concentration group, to about 61.5 percent mean cumulative mortality at 6 DPF, then remained constant. The mean hatching success for all dilutions was presented.

  5. Global warming and climate change in Amazonia: Climate-vegetation feedback and impacts on water resources

    Science.gov (United States)

    Marengo, José; Nobre, Carlos A.; Betts, Richard A.; Cox, Peter M.; Sampaio, Gilvan; Salazar, Luis

    This chapter constitutes an updated review of long-term climate variability and change in the Amazon region, based on observational data spanning more than 50 years of records and on climate-change modeling studies. We start with the early experiments on Amazon deforestation in the late 1970s, and the evolution of these experiments to the latest studies on greenhouse gases emission scenarios and land use changes until the end of the twenty-first century. The "Amazon dieback" simulated by the HadCM3 model occurs after a "tipping point" of CO2 concentration and warming. Experiments on Amazon deforestation and change of climate suggest that once a critical deforestation threshold (or tipping point) of 40-50% forest loss is reached in eastern Amazonia, climate would change in a way which is dangerous for the remaining forest. This may favor a collapse of the tropical forest, with a substitution of the forest by savanna-type vegetation. The concept of "dangerous climate change," as a climate change, which induces positive feedback, which accelerate the change, is strongly linked to the occurrence of tipping points, and it can be explained as the presence of feedback between climate change and the carbon cycle, particularly involving a weakening of the current terrestrial carbon sink and a possible reversal from a sink (as in present climate) to a source by the year 2050. We must, therefore, currently consider the drying simulated by the Hadley Centre model(s) as having a finite probability under global warming, with a potentially enormous impact, but with some degree of uncertainty.

  6. Ecosystem maturation follows the warming of the Arctic fjords

    Directory of Open Access Journals (Sweden)

    Jan Marcin Węsławski

    2017-10-01

    Full Text Available Two fjords in West Spitsbergen (Hornsund 77°N and Kongsfjorden 79°N differ with regard to their exposure towards increasingly warm Atlantic water inflow. Hornsund remains in many respects cooler than Kongsfjorden (on average 2°C SST in summer and is less influenced by warmer and more saline Atlantic waters. Reported changes in the physical environment (temperature rise, freshwater inflow, salinity drop, turbidity, fast-ice reduction, coastal change are discussed in the context of biological observations in the pelagic and benthic realms with special reference to krill (Euphausiacea. We conclude that well-documented changes in the physical environment have had little effect on the fjord biota and that both organisms and their ecological functions in the fjords are well adapted to the scale of ongoing change. The observed changes fit the definition of ecosystem maturation, with greater diversity, a more complex food web and dispersed energy flow at the warmer site.

  7. Ultraviolet-B radiation induced cross-linking improves physical properties of cold- and warm-water fish gelatin gels and films.

    Science.gov (United States)

    Otoni, Caio G; Avena-Bustillos, Roberto J; Chiou, Bor-Sen; Bilbao-Sainz, Cristina; Bechtel, Peter J; McHugh, Tara H

    2012-09-01

    Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm(2). Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rheological properties of the solutions as well as the tensile and water vapor barrier properties of the films were characterized. SDS-PAGE and refractive index results indicated cross-linking of gelatin chains after exposure to radiation. Interestingly, UV-B treated samples displayed higher gel strengths, with cold- and warm-water fish gelatin having gel strength increases from 1.39 to 2.11 N and from 7.15 to 8.34 N, respectively. In addition, both gelatin samples exhibited an increase in viscosity for higher UV doses. For gelatin films, the cold-water fish gelatin samples made from irradiated granules showed greater tensile strength. In comparison, the warm-water gelatin films made from irradiated granules had lower tensile strength, but better water vapor barrier properties. This might be due to the UV induced cross-linking in warm-water gelatin that disrupted helical structures. Journal of Food Science copy; 2012 Institute of Food Technologists® No claim to original US government works.

  8. Water quality in Atlantic rainforest mountain rivers (South America): quality indices assessment, nutrients distribution, and consumption effect.

    Science.gov (United States)

    Avigliano, Esteban; Schenone, Nahuel

    2016-08-01

    The South American Atlantic rainforest is a one-of-a-kind ecosystem considered as a biodiversity hotspot; however, in the last decades, it was intensively reduced to 7 % of its original surface. Water resources and water quality are one of the main goods and services this system provides to people. For monitoring and management recommendations, the present study is focused on (1) determining the nutrient content (nitrate, nitrite, ammonium, and phosphate) and physiochemical parameters (temperature, pH, electrical conductivity, turbidity, dissolved oxygen, and total dissolved solids) in surface water from 24 rainforest mountain rivers in Argentina, (2) analyzing the human health risk, (3) assessing the environmental distribution of the determined pollutants, and (4) analyzing water quality indices (WQIobj and WQImin). In addition, for total coliform bacteria, a dataset was used from literature. Turbidity, total dissolved solids, and nitrite (NO2 (-)) exceeded the guideline value recommended by national or international guidelines in several sampling stations. The spatial distribution pattern was analyzed by Principal Component Analysis and Factor Analysis (PCA/FA) showing well-defined groups of rivers. Both WQI showed good adjustment (R (2) = 0.89) and rated water quality as good or excellent in all sampling sites (WQI > 71). Therefore, this study suggests the use of the WQImin for monitoring water quality in the region and also the water treatment of coliform, total dissolved solids, and turbidity.

  9. Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust

    Science.gov (United States)

    Guerreiro, Catarina V.; Baumann, Karl-Heinz; Brummer, Geert-Jan A.; Fischer, Gerhard; Korte, Laura F.; Merkel, Ute; Sá, Carolina; de Stigter, Henko; Stuut, Jan-Berend W.

    2017-10-01

    Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12° N, 49° W and M2 at 14° N, 37° W) collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic. The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ) taxa (Florisphaera profunda, Gladiolithus flabellatus) but also included upper photic zone (UPZ) taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.). The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241×107 ± 76×107 coccoliths m-2 d-1 at station M4 compared to only 66×107 ± 31×107 coccoliths m-2 d-1 at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, favoured by the westward deepening of the thermocline and nutricline. Still, most UPZ species also contributed to higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. Such was the case of two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi in January and April 2013 at M4, indicating a fast response to the nutrient enrichment of the UPZ, probably by wind-forced mixing. Later, increased fluxes of G. oceanica and E. huxleyi in October-November 2013 coincided with the occurrence of Amazon-River-affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust flux peaks, we propose a scenario in which atmospheric dust also

  10. Simulated North Atlantic-Nordic Seas water mass exchanges in an isopycnic coordinate OGCM

    OpenAIRE

    Nilsen, Jan Even Øie; Gao, Yongqi; Drange, Helge; Furevik, Tore; Bentsen, Mats

    2003-01-01

    The variability in the volume exchanges between the North Atlantic and the Nordic Seas during the last 50 years is investigated using a synoptic forced, global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The simulated volume fluxes agree with the existing observations. The net volume flux across the Faroe-Shetland Channel (FSC) is positively correlated with the net flux through the Denmark Strait (DS; R = 0.74 for 3 years low pass filtering), but negatively correlated with ...

  11. Citizen science shows systematic changes in the temperature difference between air and inland waters with global warming.

    Science.gov (United States)

    Weyhenmeyer, Gesa A; Mackay, Murray; Stockwell, Jason D; Thiery, Wim; Grossart, Hans-Peter; Augusto-Silva, Pétala B; Baulch, Helen M; de Eyto, Elvira; Hejzlar, Josef; Kangur, Külli; Kirillin, Georgiy; Pierson, Don C; Rusak, James A; Sadro, Steven; Woolway, R Iestyn

    2017-03-06

    Citizen science projects have a long history in ecological studies. The research usefulness of such projects is dependent on applying simple and standardized methods. Here, we conducted a citizen science project that involved more than 3500 Swedish high school students to examine the temperature difference between surface water and the overlying air (T w -T a ) as a proxy for sensible heat flux (Q H ). If Q H is directed upward, corresponding to positive T w -T a , it can enhance CO 2 and CH 4 emissions from inland waters, thereby contributing to increased greenhouse gas concentrations in the atmosphere. The students found mostly negative T w -T a across small ponds, lakes, streams/rivers and the sea shore (i.e. downward Q H ), with T w -T a becoming increasingly negative with increasing T a . Further examination of T w -T a using high-frequency temperature data from inland waters across the globe confirmed that T w -T a is linearly related to T a . Using the longest available high-frequency temperature time series from Lake Erken, Sweden, we found a rapid increase in the occasions of negative T w -T a with increasing annual mean T a since 1989. From these results, we can expect that ongoing and projected global warming will result in increasingly negative T w -T a , thereby reducing CO 2 and CH 4 transfer velocities from inland waters into the atmosphere.

  12. Subarcsecond resolution observations of warm water towards three deeply embedded low-mass protostars

    DEFF Research Database (Denmark)

    Persson, Magnus Vilhelm; Jørgensen, Jes Kristian; van Dishoeck, Ewine F.

    2012-01-01

    in the IRAS4A binary; in addition CH3OCH3, C2H5CN, and SO2 are detected. Extended water emission is seen towards IRAS2A, possibly associated with the outflow. The detections in all systems suggests that the presence of water on 96 %) is frozen out on dust grains at these scales. The derived abundances of CH3...

  13. About opportunities of the sharing of city infrastructure centralized warmly - and water supply

    Science.gov (United States)

    Zamaleev, M. M.; Gubin, I. V.; Sharapov, V. I.

    2017-11-01

    It is shown that joint use of engineering infrastructure of centralized heat and water supply of consumers will be the cost-efficient decision for municipal services of the city. The new technology for regulated heating of drinking water in the condenser of steam turbines of combined heat and power plant is offered. Calculation of energy efficiency from application of new technology is executed.

  14. Significant Features of Warm Season Water Vapor Flux Related to Heavy Rainfall and Draught in Japan

    Science.gov (United States)

    Nishiyama, Koji; Iseri, Yoshihiko; Jinno, Kenji

    2009-11-01

    In this study, our objective is to reveal complicated relationships between spatial water vapor inflow patterns and heavy rainfall activities in Kyushu located in the western part of Japan, using the outcomes of pattern recognition of water vapor inflow, based on the Self-Organizing Map. Consequently, it could be confirmed that water vapor inflow patterns control the distribution and the frequency of heavy rainfall depending on the direction of their fluxes and the intensity of Precipitable water. Historically serious flood disasters in South Kyushu in 1993 were characterized by high frequency of the water vapor inflow patterns linking to heavy rainfall. On the other hand, severe draught in 1994 was characterized by inactive frontal activity that do not related to heavy rainfall.

  15. Absence of Rotation Perception during Warm Water Caloric Irrigation in Some Seniors with Postural Instability.

    Science.gov (United States)

    Chiarovano, Elodie; Vidal, Pierre-Paul; Magnani, Christophe; Lamas, Georges; Curthoys, Ian S; de Waele, Catherine

    2016-01-01

    Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility, and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied. Twenty senior subjects were included in the study, and separated in two groups: 10 seniors reporting postural instability (PI) and exhibiting absence of vestibular perception when they tested with caloric stimulation and 10 sex- and age-matched seniors with no such problems (controls). We assessed vestibular perception on a binary rating scale during the warm irrigation of the caloric test. The function of the various vestibular receptors was assessed using video head impulse test (vHIT), caloric tests, and cervical and ocular vestibular-evoked myogenic potentials. The Equitest was used to evaluate balance. No horizontal canal dysfunction assessed using both caloric test and vHIT was detected in either group. No significant difference was detected between PI and control groups for the peak SPV of caloric-induced ocular nystagmus or for the HVOR gain. All the controls perceived rotation when the maximal SPV during warm irrigation was equal to or ≥15°/s. None of the subjects in the PI group perceived rotation even while the peak SPV exceeded 15°/s, providing objective evidence of normal peripheral horizontal canal function. All the PI group had abnormal Equitest results, particularly in the two last conditions. These investigations show for the first time that vestibular perception can be absent during a caloric test despite normal horizontal canal function. We call this as dissociation vestibular neglect. Patients with poor vestibular perception may not be aware of postural perturbations and so will not correct for them. Thus, falls in the elderly may result, among other factors, from

  16. Absence of rotation perception during warm water caloric irrigation in some seniors with postural instability

    Directory of Open Access Journals (Sweden)

    Elodie eChiarovano

    2016-01-01

    Full Text Available Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied.Twenty senior subjects were included in the study separated in two groups: 10 seniors reporting postural instability (PI and exhibiting absence of vestibular perception when they tested with caloric stimulation and 10 sex and age-matched seniors with no such problems (controls. We assessed vestibular perception on a binary rating scale during the warm irrigation of the caloric test. The function of the various vestibular receptors was assessed using video-head impulse test (vHIT, caloric tests, and cervical and ocular VEMPs. The Equitest was used to evaluate balance. No horizontal canal dysfunction assessed using both caloric test and vHIT was detected in either group. No significant difference was detected between PI and control groups for the peak SPV of caloric induced ocular nystagmus or for the HVOR gain. All of the controls perceived rotation when the maximal SPV during warm irrigation was equal to or greater than 15°/s. None of the subjects in the PI group perceived rotation even while the peak SPV exceeded 15°/s, providing objective evidence of normal peripheral horizontal canal function. All of the PI group had abnormal Equitest results, particularly in the two last conditions.These investigations show for the first time that vestibular perception can be absent during a caloric test despite normal horizontal canal function. We call this dissociation vestibular neglect. Patients with poor vestibular perception may not be aware of postural perturbations and so will not correct for them. Thus, falls in the elderly may result, amongst other factors, from a

  17. Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

    Directory of Open Access Journals (Sweden)

    M. Wary

    2017-06-01

    Full Text Available Dansgaard–Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48–30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that re-emerged in the Nordic Seas and provided moisture towards Greenland summit.

  18. Insights into North Atlantic deep water formation during the peak interglacial interval of Marine Isotope Stage 9 (MIS 9)

    Science.gov (United States)

    Mokeddem, Zohra; McManus, Jerry F.

    2017-11-01

    Foraminifera abundance and stable isotope records from ODP Site 984 (61.25°N, 24.04°W, 1648 m) in the North Atlantic are used to reconstruct surface circulation variations and the relative strength of the North Atlantic Deep Water (NADW) formation over the period spanning the peak warmth of Marine Interglacial Stage (MIS) 9e ( 324-336 ka). This interval includes the preceding deglaciation, Termination 4 (T4), and the subsequent glacial inception of MIS 9d. The records indicate a greatly reduced contribution of NADW during T4, as observed in more recent deglaciations. In contrast with the most recent deglaciation, the lack of a significant NADW signal extended from T4 well into the peak interglacial MIS 9e and persisted nearly until the transition to the subsequent glacial stage MIS 9d. Although NADW formation resumed during MIS 9e, only depths greater than 2000 m appear to have been ventilated. The poorly ventilated intermediate depth of Site 984 (<2000 m) may have resulted on one hand from a general reduction of deep water ventilation by NADW during the study interval or, on the other hand, from different pathways of the spread of newly formed NADW that bypassed the study location. The intermediate depths may have also been invaded by southern-sourced waters as the formation of intermediate depth NADW weakened. The absence of any significant NADW signal at the water depth of Site 984 during the climatic optimum contrasts sharply with subsequent interglacial peaks (MIS 5e and the Holocene). Despite the perturbed intermediate depth circulation, oceanic heat transport northeastward was not interrupted and may have contributed to the relatively mild interglacial conditions of MIS 9e.

  19. Effect of warming and nitrogen addition on evapotranspiration and water use efficiency in a wheat-soybean/fallow rotation from 2010 to 2014

    DEFF Research Database (Denmark)

    Liu, Liting; Hu, Chunsheng; Olesen, Jørgen Eivind

    2016-01-01

    Evapotranspiration (ET) and water use efficiency (WUE) are critical indexes in water flux cycles of croplands, being affected by climate change. However, field studies addressing influence of experimental warming on ET and WUE in semi-arid cropland are highly deficient. A two-factor experiment......, including soil temperature [ambient (C) and increased average 1.5 °C (T) at 5 cm soil depth] and nitrogen fertilizer (N) [without (N0) and with 315 kg N ha−1 input (N1)], was conducted from 2010 to 2014 in North China Plain to measure ET and WUE of wheat-soybean/fallow rotation. In the N1 treatment, warming...

  20. The combined effects of ocean warming and acidification on shallow-water meiofaunal assemblages.

    Science.gov (United States)

    Lee, Matthew R; Torres, Rodrigo; Manríquez, Patricio H

    2017-10-01

    Climate change due to increased anthropogenic CO 2 in the atmosphere is causing an increase in seawater temperatures referred to as ocean warming and a decrease in seawater pH, referred to as ocean acidification. The meiofauna play an important role in the ecology of marine ecosystems and the functions they provide. Using microcosms, meiofaunal assemblages were exposed to two temperatures (15 and 19 °C) and two pHs (pCO 2 of 400 and 1000 ppm), both individually and in combination, for a period of 90 days. The hypothesis that increased temperature will increase meiofaunal abundance was not supported. The hypothesis that a reduced pH will reduce meiofaunal abundance and species richness was supported. The combination of future conditions of temperature and pH (19 °C and pCO 2 of 1000 ppm) did not affect overall abundance but the structure of the nematode assemblage changed becoming dominated by a few opportunistic species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. EFFECT OF WARM WATER COMPRESS THERAPY ON THE INCIDENCE OF HYPEREMIA IN PHLEBITIS PATIENTS AT THE INPATIENT WARD OF BRIGJEND H. HASAN BASRI GENERAL HOSPITAL KANDANGAN

    Directory of Open Access Journals (Sweden)

    Nurul Hidayah

    2017-09-01

    Full Text Available Abstract: This study aims to determine the effect of warm water compress therapy on the incidence of hyperemia in 40 patients with phlebitis at the Inpatient Installation of H. Hasan Basry General Hospital Kandangan. Research method used quasi-experimental with two group; control and intervention. The control group was untreated phlebitis, while the intervention group was a phlebitis patient treated with warm water compresses. Data collection was collected by measuring the redness diameter before and after warm compress therapy. The result showed that the mean of intervention group diameter before treatment 49.3 mm and after treatment 40.2 mm. The mean diameter of control group before treatment 48.1 mm and after treatment 46.4 mm. The mean diameter of intervention group was decreased 9.1 mm and 1.7 mm in the control group. Statistically result test show that there was a significant difference of mean hyperemia diameter between intervention and control group (p<0.05. Statistically result test also shows that there was a significant difference of mean hyperemia between pre- and post-treatment with warm water (p<0.05. It was concluded that the warm compress therapy could decreased the incidence of hyperemia in phlebitis patients.

  2. Uptake of Iodide From Water in Atlantic Halibut Larvae (Hippoglossus Hippoglossus L.)

    DEFF Research Database (Denmark)

    Moren, Mari; Sloth, Jens Jørgen; Hamre, Kristin

    2008-01-01

    The natural diet of marine fish larvae, copepods, contain 60-350 mg I kg(-1), while live feed used in commercial hatcheries have iodine concentrations in the range of 1 mg kg(-1). Seawater is also considered to be an important source of iodine for marine fish. The question asked in this study is ......M. The uptake was partly blocked by perchlorate (ClO3-) which is a known inhibitor of the sodium iodide symporter. This indicates that the Atlantic halibut larvae accumulate iodide through both specific and non-specific uptake pathways....

  3. DNA barcoding reveals a cryptic nemertean invasion in Atlantic and Mediterranean waters

    Science.gov (United States)

    Fernández-Álvarez, Fernando Ángel; Machordom, Annie

    2013-09-01

    For several groups, like nemerteans, morphology-based identification is a hard discipline, but DNA barcoding may help non-experts in the identification process. In this study, DNA barcoding is used to reveal the cryptic invasion of Pacific Cephalothrix cf. simula into Atlantic and Mediterranean coasts. Although DNA barcoding is a promising method for the identification of Nemertea, only 6 % of the known number of nemertean species is currently associated with a correct DNA barcode. Therefore, additional morphological and molecular studies are necessary to advance the utility of DNA barcoding in the characterisation of possible nemertean alien invasions.

  4. Impacts of recent drought and warm years on water resources and electricity supply worldwide

    NARCIS (Netherlands)

    Vliet, van M.T.H.; Sheffield, Justin; Wiberg, David; Wood, Eric F.

    2016-01-01

    Recent droughts and heatwaves showed the vulnerability of the electricity sector to surface water constraints with reduced potentials for thermoelectric power and hydropower generation in different regions. Here we use a global hydrological-electricity modelling framework to quantify the impacts of

  5. Growth hormone and prolactin responses during partial and whole body warm-water immersions.

    Science.gov (United States)

    Koska, J; Rovensky, J; Zimanova, T; Vigas, M

    2003-05-01

    To elucidate the role of core and skin thermoreceptors in the release of growth hormone (GH) and prolactin (PRL), a sequence of two experiments using whole-body (head-out) and partial (one forearm) hot water immersions was performed. Experiment 1: Nine healthy men were exposed to head-out and partial water immersions (25 min, 38-39 degrees C). Head-out immersion increased the core temperature (38.0 +/- 0.1 vs. 36.7 +/- 0.1 degrees C, P immersion the core temperature was slightly elevated (36.8 +/- 0.1 vs. 36.6 +/- 0.1, P immersed one forearm once in 39 degrees C and once in 38 degrees C water. The measurements were performed in 5-min intervals. The GH concentration increased gradually from the beginning of the immersions (min 10; 39 degrees C: 1.9 +/- 1.0 vs. 0.6 +/- 0.3 ng mL(-1), P Immersion in 38 degrees C water did not induce core temperature changes. Peripheral thermoreceptors are involved in GH release when the body is exposed to elevated environmental temperature while a substantial elevation of core temperature is a precondition of PRL release.

  6. Annual performance of building-integrated photovoltaic/water-heating system for warm climate application

    International Nuclear Information System (INIS)

    Chow, T.T.; Chan, A.L.S.; Fong, K.F.; Lin, Z.; He, W.; Ji, J.

    2009-01-01

    A building-integrated photovoltaic/water-heating (BiPVW) system is able to generate higher energy output per unit collector area than the conventional solar systems. Through computer simulation with energy models developed for this integrative solar system in Hong Kong, the results showed that the photovoltaic/water-heating (PVW) system has economic advantages over the conventional photovoltaic (PV) installation. The system thermal performance under natural water circulation was found better than the pump-circulation mode. For a specific BiPVW system at a vertical wall of a fully air-conditioned building and with collectors equipped with flat-box-type thermal absorber and polycrystalline silicon cells, the year-round thermal and cell conversion efficiencies were found respectively 37.5% and 9.39% under typical Hong Kong weather conditions. The overall heat transmission through the PVW wall is reduced to 38% of the normal building facade. When serving as a water pre-heating system, the economical payback period was estimated around 14 years. This greatly enhances the PV market opportunities. (author)

  7. Variations in Mediterranean-Atlantic exchange across the late Pliocene climate transition

    Science.gov (United States)

    García-Gallardo, Ángela; Grunert, Patrick; Piller, Werner E.

    2018-03-01

    Mediterranean-Atlantic exchange through the Strait of Gibraltar plays a significant role in the global ocean-climate dynamics in two ways. On one side, the injection of the saline and warm Mediterranean Outflow Water (MOW) contributes to North Atlantic deep-water formation. In return, the Atlantic inflow is considered a sink of less saline water for the North Atlantic Ocean. However, while the history of MOW is the focus of numerous studies, the Pliocene Atlantic inflow has received little attention so far. The present study provides an assessment of the Mediterranean-Atlantic exchange with a focus on the Atlantic inflow strength and its response to regional and global climate from 3.33 to 2.60 Ma. This time interval comprises the mid-Pliocene warm period (MPWP; 3.29-2.97 Ma) and the onset of the Northern Hemisphere glaciation (NHG). For this purpose, gradients in surface δ18O records of the planktonic foraminifer Globigerinoides ruber between the Integrated Ocean Drilling Program (IODP) Hole U1389E (Gulf of Cádiz) and Ocean Drilling Program (ODP) Hole 978A (Alboran Sea) have been evaluated. Interglacial stages and warm glacials of the MPWP revealed steep and reversed (relative to the present) W-E δ18O gradients suggesting a weakening of Mediterranean-Atlantic exchange likely caused by high levels of relative humidity in the Mediterranean region. In contrast, periods of stronger inflow are indicated by flat δ18O gradients due to more intense arid conditions during the severe glacial Marine Isotope Stage (MIS) M2 and the initiation of NHG (MIS G22, G14, G6-104). Intensified Mediterranean-Atlantic exchange in cold periods is linked to the occurrence of ice-rafted debris (IRD) at low latitudes and a weakening of the Atlantic Meridional Overturning Circulation (AMOC). Our results thus suggest the development of a negative feedback between AMOC and exchange rates at the Strait of Gibraltar in the latest Pliocene as it has been proposed for the late Quaternary.

  8. Solar warming systems of water installed in Colombia. Photovoltaic solar systems installed in the Country

    International Nuclear Information System (INIS)

    Rodriguez P, F.

    1995-01-01

    Between the systems that operate as of solar energy, the solar collectors to heat water have had wide use and application in the Country. Basically, a solar collector is constituted by: Box, thermal insulator, ducts and transparent roof. Generally, the used materials are the following: As thermal insulator: Polyurethane or glass fiber; as absorbent plate: Copper or aluminum, painting in dull black or selective surfaces; for the ducts: Generally it is used copper pipeline; and for the cover: Common glass or temperate glass

  9. Contrasting cesium dynamics in neighboring deep and shallow warm-water reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Pinder, John E. [Department of Biology, Texas Christian University, Ft. Worth, TX 76129 (United States); Hinton, T.G., E-mail: thomas.hinton@irsn.f [Institute for Radiation Protection and Nuclear Safety, Cadarache, 13115 France (France); Whicker, F.W. [Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1618 (United States)

    2010-09-15

    To measure the long term retention and seasonal dynamics of an initial 4 kg addition of {sup 133}Cs into an 11.4-ha, 157,000 m{sup 3} reservoir (Pond 4, near Aiken, South Carolina, USA), the concentrations and inventories of {sup 133}Cs in the water column were measured at periodical intervals for 522 days following the 1 August, 1999 release. After rapid declines in concentrations and inventories during the first 90 days, the {sup 133}Cs concentrations in the water column declined at an average proportional rate of 0.004 d{sup -1}. However, there were periods of less rapid and more rapid rates of declines, and these were correlated with periods of increasing and decreasing K concentrations in the water column. The decline rates were less and the K concentrations greater in the winter than in the summer. In the deeper, neighboring monomictic reservoirs of Par Pond and Pond B, a yearly cycle of increasing and decreasing {sup 137}Cs concentrations in the water column is driven by anoxic remobilization of Cs from the sediments into a persistent summer hypolimnion. In Pond 4, whose mean depth of 1.6 m is too shallow to support a persistent anoxic hypolimnion, the pattern of yearly dynamics for K and Cs appear to be related to the accumulation and release of these elements from the extensive, seasonal macrophyte communities. The contrasting results between Pond 4 and Pond B suggest that a full appreciation of the relative importance of 1) anoxic remobilization and 2) accumulation and release by macrophytes in these systems remains to be established.

  10. Biomarker candidate discovery in Atlantic cod (Gadus morhua) continuously exposed to North Sea produced water from egg to fry

    DEFF Research Database (Denmark)

    Bohne-Kjersem, Anneli; Bache, Nicolai; Meier, Sonnich

    2010-01-01

    were able to compare the induced changes by PW to the mode of action of oestrogens. Changes in the proteome in response to exposure in whole cod fry (approximately 80 days post-hatching, dph) were detected by two-dimensional gel electrophoresis and image analysis and identified by MALDI-ToF-ToF mass...... spectrometry, using a newly developed cod EST database and the NCBI database. Many of the protein changes occurred at low levels (0.01% and 0.1% PW) of exposure, indicating putative biological responses at lower levels than previously detected. Using discriminant analysis, we identified a set of protein...... changes that may be useful as biomarker candidates of produced water (PW) and oestradiol exposure in Atlantic cod fry. The biomarker candidates discovered in this study may, following validation, prove effective as diagnostic tools in monitoring exposure and effects of discharges from the petroleum...

  11. Primary production and chlorophyll distributions in the subtropical and tropical waters of the Atlantic Ocean in the autumn of 2002

    Science.gov (United States)

    Vedernikov, V. I.; Gagarin, V. I.; Demidov, A. B.; Burenkov, V. I.; Stunzhas, P. A.

    2007-06-01

    In October and November 2002, high and relatively high values of the chlorophyll a concentration at the sea surface ( C chl) were observed in the English Channel (0.47 mg/m3), in the waters of the North Atlantic Current (0.25 mg/m3), in the tropical and subtropical anticyclonic gyres (0.07-0.42 mg/m3), and also in the southwestern region of the southern subtropical anticyclonic gyre (usually 0.11-0.23 mg/m3). The central regions of the southern subtropical anticyclonic gyre (SATG) and the North Atlantic tropical gyre (NATR) were characterized by lower values of C chl (0.02-0.08 mg/m3 for the SATG and 0.07-0.14 mg/m3 for the NATR). At most of the SATG stations, the values of the surface primary production ( C phs) varied from 2.5 to 5.5 mg C/m3 per day and were mainly defined by the fluctuations of C chl ( r = +0.78) rather than by those of the assimilation number ( r = +0.54). The low assimilation activity of phytoplankton in these waters (1.3-4.6 mg chl a per hour) pointed to a lack of nutrients. An analysis of the variability of their concentration and the composition of photosynthetic pigments showed that, in the waters north of 30° N, the growth of phytoplankton was mostly restricted by the deficiency of nitrogen, while, in more southern areas, at the majority of stations (about 60%), the phosphorus concentrations were the minimum. At the low concentrations of nitrates and nitrites, ammonium represented itself as a buffer that prevented planktonic algae from extreme degrees of nitric starvation. In the tropical waters and in the waters of the SATG, the primary production throughout the water column varied from 240 to 380 mg C/m2 30° per day. This level of productivity at stations with low values of C chl (photosynthesis based on in situ measurements point to the high efficiency of utilizing the penetrating solar radiation by phytoplankton on cloudy days.

  12. Effects of highway construction on stream water quality and macroinvertebrate condition in a mid-atlantic highlands watershed, USA.

    Science.gov (United States)

    Chen, Yushun; Viadero, Roger C; Wei, Xinchao; Fortney, Ronald; Hedrick, Lara B; Welsh, Stuart A; Anderson, James T; Lin, Lian-Shin

    2009-01-01

    Refining best management practices (BMPs) for future highway construction depends on a comprehensive understanding of environmental impacts from current construction methods. Based on a before-after-control impact (BACI) experimental design, long-term stream monitoring (1997-2006) was conducted at upstream (as control, n = 3) and downstream (as impact, n = 6) sites in the Lost River watershed of the Mid-Atlantic Highlands region, West Virginia. Monitoring data were analyzed to assess impacts of during and after highway construction on 15 water quality parameters and macroinvertebrate condition using the West Virginia stream condition index (WVSCI). Principal components analysis (PCA) identified regional primary water quality variances, and paired t tests and time series analysis detected seven highway construction-impacted water quality parameters which were mainly associated with the second principal component. In particular, impacts on turbidity, total suspended solids, and total iron during construction, impacts on chloride and sulfate during and after construction, and impacts on acidity and nitrate after construction were observed at the downstream sites. The construction had statistically significant impacts on macroinvertebrate index scores (i.e., WVSCI) after construction, but did not change the overall good biological condition. Implementing BMPs that address those construction-impacted water quality parameters can be an effective mitigation strategy for future highway construction in this highlands region.

  13. Monitoring of tritium, 60Co and 137Cs in the vicinity of the warm water outlet of the Paks Nuclear Power Plant, Hungary.

    Science.gov (United States)

    Janovics, R; Bihari, Á; Papp, L; Dezső, Z; Major, Z; Sárkány, K E; Bujtás, T; Veres, M; Palcsu, L

    2014-02-01

    Danube water, sediment and various aquatic organisms (snail, mussel, predatory and omnivorous fish) were collected upstream (at a background site) and downstream of the outlet of the warm water channel of Paks Nuclear Power Plant. Gamma emitters, tissue free-water tritium (TFWT) and total organically-bound tritium (T-OBT) measurements were performed. A slight contribution of the power plant to the natural tritium background concentration was measured in water samples from the Danube section downstream of the warm water channel. Sediment samples also contained elevated tritium concentrations, along with a detectable amount of (60)Co. In the case of biota samples, TFWT exhibited only a very slight difference compared to the tritium concentration of the Danube water, however, the OBT was higher than the tritium concentration in the Danube, independent of the origin of the samples. The elevated OBT concentration in the mollusc samples downstream of the warm water channel may be attributed to the excess emission from the nuclear power plant. The whole data set obtained was used for dose rate calculations and will be contributed to the development of the ERICA database. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. South Atlantic circulation in a world ocean model

    Directory of Open Access Journals (Sweden)

    M. H. England

    1994-08-01

    Full Text Available The circulation in the South Atlantic Ocean has been simulated within a global ocean general circulation model. Preliminary analysis of the modelled ocean circulation in the region indicates a rather close agreement of the simulated upper ocean flows with conventional notions of the large-scale geostrophic currents in the region. The modelled South Atlantic Ocean witnesses the return flow and export of North Atlantic Deep Water (NADW at its northern boundary, the inflow of a rather barotropic Antarctic Circumpolar Current (ACC through the Drake Passage, and the inflow of warm saline Agulhas water around the Cape of Good Hope. The Agulhas leakage amounts to 8.7 Sv, within recent estimates of the mass transport shed westward at the Agulhas retroflection. Topographic steering of the ACC dominates the structure of flow in the circumpolar ocean. The Benguela Current is seen to be fed by a mixture of saline Indian Ocean water (originating from the Agulhas Current and fresher Subantarctic surface water (originating in the ACC. The Benguela Current is seen to modify its flow and fate with depth; near the surface it flows north-westwards bifurcating most of its transport northward into the North Atlantic Ocean (for ultimate replacement of North Atlantic surface waters lost to the NADW conveyor. Deeper in the water column, more of the Benguela Current is destined to return with the Brazil Current, though northward flows are still generated where the Benguela Current extension encounters the coast of South America. At intermediate levels, these northward currents trace the flow of Antarctic Intermediate Water (AAIW equatorward, though even more AAIW is seen to recirculate poleward in the subtropical gyre. In spite of the model's rather coarse resolution, some subtle features of the Brazil-Malvinas Confluence are simulated rather well, including the latitude at which the two currents meet. Conceptual diagrams of the recirculation and interocean exchange of

  15. South Atlantic circulation in a world ocean model

    Directory of Open Access Journals (Sweden)

    Matthew H. England

    Full Text Available The circulation in the South Atlantic Ocean has been simulated within a global ocean general circulation model. Preliminary analysis of the modelled ocean circulation in the region indicates a rather close agreement of the simulated upper ocean flows with conventional notions of the large-scale geostrophic currents in the region. The modelled South Atlantic Ocean witnesses the return flow and export of North Atlantic Deep Water (NADW at its northern boundary, the inflow of a rather barotropic Antarctic Circumpolar Current (ACC through the Drake Passage, and the inflow of warm saline Agulhas water around the Cape of Good Hope. The Agulhas leakage amounts to 8.7 Sv, within recent estimates of the mass transport shed westward at the Agulhas retroflection. Topographic steering of the ACC dominates the structure of flow in the circumpolar ocean. The Benguela Current is seen to be fed by a mixture of saline Indian Ocean water (originating from the Agulhas Current and fresher Subantarctic surface water (originating in the ACC. The Benguela Current is seen to modify its flow and fate with depth; near the surface it flows north-westwards bifurcating most of its transport northward into the North Atlantic Ocean (for ultimate replacement of North Atlantic surface waters lost to the NADW conveyor. Deeper in the water column, more of the Benguela Current is destined to return with the Brazil Current, though northward flows are still generated where the Benguela Current extension encounters the coast of South America. At intermediate levels, these northward currents trace the flow of Antarctic Intermediate Water (AAIW equatorward, though even more AAIW is seen to recirculate poleward in the subtropical gyre. In spite of the model's rather coarse resolution, some subtle features of the Brazil-Malvinas Confluence are simulated rather well, including the latitude at which the two currents meet. Conceptual diagrams of the recirculation and interocean

  16. A cascade of warming impacts brings bluefin tuna to Greenland waters

    DEFF Research Database (Denmark)

    MacKenzie, Brian R.; Payne, Mark R.; Boje, Jesper

    2014-01-01

    Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predator-prey dynamics in food webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species in ec...... impacts is restructuring the food web in east Greenland waters.......Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predator-prey dynamics in food webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species...

  17. A novel marine mesocosm facility to study global warming, water quality, and ocean acidification

    OpenAIRE

    Duarte, Gustavo; Calderon, Emiliano N.; Pereira, Cristiano M.; Marangoni, Laura F. B.; Santos, Henrique F.; Peixoto, Raquel S.; Bianchini, Adalto; Castro, Clovis B.

    2015-01-01

    Abstract We describe a completely randomizable flow?through outdoor mesocosm for climate change and ecotoxicology studies that was built with inexpensive materials. The 16 raceway tanks allow up to 6? water renewal per hour, avoiding changes in natural abiotic seawater conditions. We use an open?source hardware board (Arduino) that was adapted to control heaters and an innovative CO 2 injection system. This system reduced seawater pH up to ?0.9 units and increased temperature up to +6?C in th...

  18. Rapid response of hydrological loss of DOC to water table drawdown and warming in Zoige peatland: results from a mesocosm experiment.

    Science.gov (United States)

    Lou, Xue-Dong; Zhai, Sheng-Qiang; Kang, Bing; Hu, Ya-Lin; Hu, Li-Le

    2014-01-01

    A large portion of the global carbon pool is stored in peatlands, which are sensitive to a changing environment conditions. The hydrological loss of dissolved organic carbon (DOC) is believed to play a key role in determining the carbon balance in peatlands. Zoige peatland, the largest peat store in China, is experiencing climatic warming and drying as well as experiencing severe artificial drainage. Using a fully crossed factorial design, we experimentally manipulated temperature and controlled the water tables in large mesocosms containing intact peat monoliths. Specifically, we determined the impact of warming and water table position on the hydrological loss of DOC, the exported amounts, concentrations and qualities of DOC, and the discharge volume in Zoige peatland. Our results revealed that of the water table position had a greater impact on DOC export than the warming treatment, which showed no interactive effects with the water table treatment. Both DOC concentration and discharge volume were significantly increased when water table drawdown, while only the DOC concentration was significantly promoted by warming treatment. Annual DOC export was increased by 69% and 102% when the water table, controlled at 0 cm, was experimentally lowered by -10 cm and -20 cm. Increases in colored and aromatic constituents of DOC (measured by Abs(254 nm), SUVA(254 nm), Abs(400 nm), and SUVA(400 nm)) were observed under the lower water tables and at the higher peat temperature. Our results provide an indication of the potential impacts of climatic change and anthropogenic drainage on the carbon cycle and/or water storage in a peatland and simultaneously imply the likelihood of potential damage to downstream ecosystems. Furthermore, our results highlight the need for local protection and sustainable development, as well as suggest that more research is required to better understand the impacts of climatic change and artificial disturbances on peatland degradation.

  19. Rapid response of hydrological loss of DOC to water table drawdown and warming in Zoige peatland: results from a mesocosm experiment.

    Directory of Open Access Journals (Sweden)

    Xue-Dong Lou

    Full Text Available A large portion of the global carbon pool is stored in peatlands, which are sensitive to a changing environment conditions. The hydrological loss of dissolved organic carbon (DOC is believed to play a key role in determining the carbon balance in peatlands. Zoige peatland, the largest peat store in China, is experiencing climatic warming and drying as well as experiencing severe artificial drainage. Using a fully crossed factorial design, we experimentally manipulated temperature and controlled the water tables in large mesocosms containing intact peat monoliths. Specifically, we determined the impact of warming and water table position on the hydrological loss of DOC, the exported amounts, concentrations and qualities of DOC, and the discharge volume in Zoige peatland. Our results revealed that of the water table position had a greater impact on DOC export than the warming treatment, which showed no interactive effects with the water table treatment. Both DOC concentration and discharge volume were significantly increased when water table drawdown, while only the DOC concentration was significantly promoted by warming treatment. Annual DOC export was increased by 69% and 102% when the water table, controlled at 0 cm, was experimentally lowered by -10 cm and -20 cm. Increases in colored and aromatic constituents of DOC (measured by Abs(254 nm, SUVA(254 nm, Abs(400 nm, and SUVA(400 nm were observed under the lower water tables and at the higher peat temperature. Our results provide an indication of the potential impacts of climatic change and anthropogenic drainage on the carbon cycle and/or water storage in a peatland and simultaneously imply the likelihood of potential damage to downstream ecosystems. Furthermore, our results highlight the need for local protection and sustainable development, as well as suggest that more research is required to better understand the impacts of climatic change and artificial disturbances on peatland degradation.

  20. Differentiating leucine incorporation of Archaea and Bacteria throughout the water column of the eastern Atlantic using metabolic inhibitors

    OpenAIRE

    Yokokawa, T.; Sintes, E.; de Corte, D.; Olbrich, K.; Herndl, G.J.

    2012-01-01

    The abundance (based on catalyzed reporter deposition-fluorescence in situ hybrid ization, CARD-FISH) and leucine incorporation rates of Archaea and Bacteria were determined throughout the water column in the eastern Atlantic. Bacteria dominated throughout the water column, although their contribution to total prokaryotic abundance in the bathypelagic layer (1000 to 4000 m depth) was lower than in the surface and mesopelagic layers (0 to 1000 m depth). While marine Crenarchaeota Group I (MCG ...

  1. Atlantic Region

    NARCIS (Netherlands)

    Elands, B.H.M.; Bell, S.; Blok, J.

    2010-01-01

    Chapter 2 explores recreation and tourism practices in forest areas in the Atlantic region, which refers to the geographical area close to the North Sea and the Atlantic Ocean. The Atlantic countries described in this section are Belgium (Flanders and Wallonia), Denmark, Iceland, Ireland, the

  2. A novel marine mesocosm facility to study global warming, water quality, and ocean acidification.

    Science.gov (United States)

    Duarte, Gustavo; Calderon, Emiliano N; Pereira, Cristiano M; Marangoni, Laura F B; Santos, Henrique F; Peixoto, Raquel S; Bianchini, Adalto; Castro, Clovis B

    2015-10-01

    We describe a completely randomizable flow-through outdoor mesocosm for climate change and ecotoxicology studies that was built with inexpensive materials. The 16 raceway tanks allow up to 6× water renewal per hour, avoiding changes in natural abiotic seawater conditions. We use an open-source hardware board (Arduino) that was adapted to control heaters and an innovative CO 2 injection system. This system reduced seawater pH up to -0.9 units and increased temperature up to +6°C in three treatments and a control. Treatments can be continuously compared with the control and vary according to diel fluctuations, thus following the diel range observed in the sea. The mesocosm facility also includes an integrated secondary system of 48 aquaria for ecotoxicology studies. We validated the reproducibility and relevance of our experimental system by analyzing the variation of the total DNA of the microbial community extracted from corals in three elevated temperature scenarios during a 40-day experiment. We also present data from temperature, acidification, and copper contamination trials, which allowed continuous, reliable, and consistent treatment manipulations.

  3. Coccolithophore fluxes in the open tropical North Atlantic: influence of thermocline depth, Amazon water, and Saharan dust

    Directory of Open Access Journals (Sweden)

    C. V. Guerreiro

    2017-10-01

    Full Text Available Coccolithophores are calcifying phytoplankton and major contributors to both the organic and inorganic oceanic carbon pumps. Their export fluxes, species composition, and seasonal patterns were determined in two sediment trap moorings (M4 at 12° N, 49° W and M2 at 14° N, 37° W collecting settling particles synchronously from October 2012 to November 2013 at 1200 m of water depth in the open equatorial North Atlantic. The two trap locations showed a similar seasonal pattern in total coccolith export fluxes and a predominantly tropical coccolithophore settling assemblage. Species fluxes were dominated throughout the year by lower photic zone (LPZ taxa (Florisphaera profunda, Gladiolithus flabellatus but also included upper photic zone (UPZ taxa (Umbellosphaera spp., Rhabdosphaera spp., Umbilicosphaera spp., Helicosphaera spp.. The LPZ flora was most abundant during fall 2012, whereas the UPZ flora was more important during summer. In spite of these similarities, the western part of the study area produced persistently higher fluxes, averaging 241×107 ± 76×107 coccoliths m−2 d−1 at station M4 compared to only 66×107 ± 31×107 coccoliths m−2 d−1 at station M2. Higher fluxes at M4 were mainly produced by the LPZ species, favoured by the westward deepening of the thermocline and nutricline. Still, most UPZ species also contributed to higher fluxes, reflecting enhanced productivity in the western equatorial North Atlantic. Such was the case of two marked flux peaks of the more opportunistic species Gephyrocapsa muellerae and Emiliania huxleyi in January and April 2013 at M4, indicating a fast response to the nutrient enrichment of the UPZ, probably by wind-forced mixing. Later, increased fluxes of G. oceanica and E. huxleyi in October–November 2013 coincided with the occurrence of Amazon-River-affected surface waters. Since the spring and fall events of 2013 were also accompanied by two dust

  4. Subsurface watering resulted in reduced soil N2O and CO2 emissions and their global warming potentials than surface watering

    Science.gov (United States)

    Wei, Qi; Xu, Junzeng; Yang, Shihong; Liao, Linxian; Jin, Guangqiu; Li, Yawei; Hameed, Fazli

    2018-01-01

    Water management is an important practice with significant effect on greenhouse gases (GHG) emission from soils. Nitrous oxide (N2O) and carbon dioxide (CO2) emissions and their global warming potentials (GWPs) from subsurface watering soil (SUW) were investigated, with surface watering (SW) as a control. Results indicated that the N2O and CO2 emissions from SUW soils were somewhat different to those from SW soil, with the peak N2O and CO2 fluxes from SUW soil reduced by 28.9% and 19.4%, and appeared 72 h and 168 h later compared with SW. The fluxes of N2O and CO2 from SUW soils were lower than those from SW soil in both pulse and post-pulse periods, and the reduction was significantly (p0.1) lower that from SW soil. Moreover, N2O and CO2 fluxes from both watering treatments increased exponentially with increase of soil water-filled pore space (WFPS) and temperature. Our results suggest that watering soil from subsurface could significantly reduce the integrative greenhouse effect caused by N2O and CO2 and is a promising strategy for soil greenhouse gases (GHGs) mitigation. And the pulse period, contributed most to the reduction in emissions of N2O and CO2 from soils between SW and SUW, should be a key period for mitigating GHGs emissions. Response of N2O and CO2 emissions to soil WFPS and temperature illustrated that moisture was the dominant parameters that triggering GHG pulse emissions (especially for N2O), and temperature had a greater effect on the soil microorganism activity than moisture in drier soil. Avoiding moisture and temperature are appropriate for GHG emission at the same time is essential for GHGs mitigation, because peak N2O and CO2 emission were observed only when moisture and temperature are both appropriate.

  5. Walleye recruitment success is less resilient to warming water temperatures in lakes with abundant largemouth bass populations

    Science.gov (United States)

    Hansen, Gretchen J. A.; Midway, Stephen R.; Wagner, Tyler

    2018-01-01

    Lakes respond heterogeneously to climate, with implications for fisheries management. We analyzed walleye (Sander vitreus) recruitment to age-0 in 359 lakes in Wisconsin, USA, to (i) quantify the relationship between annual water temperature degree days (DD) and walleye recruitment success and (ii) identify the influence of lake characteristics — area, conductivity, largemouth bass (Micropterus salmoides) catch rates, and mean DD — on this relationship. The relationship between walleye recruitment and annual DD varied among lakes and was not distinguishable from zero overall (posterior mean = −0.11, 90% CI = −0.34, 0.15). DD effects on recruitment were negative in 198 lakes (55%) and positive in 161 (45%). The effect of annual DD was most negative in lakes with high largemouth bass densities, and, on average, the probability of recruitment was highest in large lakes with low largemouth bass densities. Conductivity and mean DD influenced neither recruitment nor the effect of annual DD. Walleye recruitment was most resilient to warming in lakes with few largemouth bass, suggesting that the effects of climate change depend on lake-specific food-web and habitat contexts.

  6. Enhanced hydrological extremes in the western United States under global warming through the lens of water vapor wave activity

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian; Xue, Daokai; Gao, Yang; Chen, Gang; Leung, Lai-Yung; Staten, Paul W.

    2018-04-23

    Understanding how regional hydrological extremes would respond to warming is a grand challenge to the community of climate change research. To address this challenge, we construct an analysis framework based on column integrated water vapor (CWV) wave activity to diagnose the wave component of the hydrological cycle that contributes to hydrological extremes. By applying the analysis to the historical and future climate projections from the CMIP5 models, we found that the wet-versus-dry disparity of daily net precipitation along a zonal band can increase at a super Clausius-Clapeyron rate due to the enhanced stirring length of wave activity at the poleward flank of the mean storm track. The local variant of CWV wave activity reveals the unique characteristics of atmospheric rivers (ARs) in terms of their transport function, enhanced mixing and hydrological cycling rate (HC). Under RCP8.5, the local moist wave activity increases by ~40% over the northeastern Pacific by the end of the 21st century, indicating more ARs hitting the west coast, giving rise to a ~20% increase in the related hydrological extremes − $ despite a weakening of the local HC.

  7. Practical ways to abate air and water pollution worldwide including a unique way to significantly curb global warming

    Energy Technology Data Exchange (ETDEWEB)

    Snell, J.R.

    1998-07-01

    This paper points out that in the next 50 years it will largely be the developing countries of the world which will continue to industrialize rapidly and hence pollute the water and air of not only their countries but that this pollution is becoming global (80% of the World's population.) From the author's 25 years of consulting experience in the developing countries, their greatest need is to have available to them low cost, innovative processes for pollution abatement will be neglected and the whole world will suffer immensely. The paper discusses in some detail the type of innovative low cost methods which have successfully been used in the categories of wastewater and solid wastes and names 6 other categories where many others exist. All these innovative methods need to be discovered, listed, and tested for quality and dependability, and then made widely available. Large Environmental Engineering Universities and International Consulting Engineering firms need to be organized to undertake these important tasks. The paper also points out the connection between Global Warming and the Solid waste industry and shows how it can be controlled inexpensively by employing a new, unique, and rapid method of converting municipal refuse into methane and then using that to make electricity. Information given in this paper could lead to a vast reduction in future pollution, with the resulting better global health and at the same time save trillions of dollars.

  8. Drivers and uncertainties of forecasted range shifts for warm-water fishes under climate and land cover change

    Science.gov (United States)

    Bouska, Kristen; Whitledge, Gregory W.; Lant, Christopher; Schoof, Justin

    2018-01-01

    Land cover is an important determinant of aquatic habitat and is projected to shift with climate changes, yet climate-driven land cover changes are rarely factored into climate assessments. To quantify impacts and uncertainty of coupled climate and land cover change on warm-water fish species’ distributions, we used an ensemble model approach to project distributions of 14 species. For each species, current range projections were compared to 27 scenario-based projections and aggregated to visualize uncertainty. Multiple regression and model selection techniques were used to identify drivers of range change. Novel, or no-analogue, climates were assessed to evaluate transferability of models. Changes in total probability of occurrence ranged widely across species, from a 63% increase to a 65% decrease. Distributional gains and losses were largely driven by temperature and flow variables and underscore the importance of habitat heterogeneity and connectivity to facilitate adaptation to changing conditions. Finally, novel climate conditions were driven by mean annual maximum temperature, which stresses the importance of understanding the role of temperature on fish physiology and the role of temperature-mitigating management practices.

  9. Trace metals in corals--hind casting environmental chemical changes in the tropical Atlantic waters

    Science.gov (United States)

    Holmes, C. W.; Koenig, A.; Ridley, W. I.; Wilson, S. A.

    2002-12-01

    As corals grow, they secrete a calcareous skeleton with the aid of photosynthetic activity of endosymbiotic dinoflagellates (zooxanthellae). The rate of this secretion varies inter-annually. Entrapped with the carbonate are trace substances that record the chemistry of the surrounding ocean. Detailing changes in chemistry requires careful and very tedious high-resolution sampling. The advent of laser ablation inductive couple plasma/mass spectroscopy (LA-ICP/MS) circumvents this sampling problem. This method also permits a continuous scan of the entire coral skeleton. Another problem has been the lack of a carbonate standard which appears to be resolved with the creation of an artificial carbonate standard (USGS MAC-1). This standard is presently undergoing rigorous analysis, but preliminary results are very positive. The LA-ICP/MS data of three Atlantic corals reveals an intriguing distribution of trace metals and boron that may be related to climatic driven chemical changes during the last hundred years. The distribution of the trace metals appears to have an association with three climate signals: 1. the strength of the North Atlantic Oscillation (NAO), 2. the local effects of El Nino in the Florida region and 3. change in oceanic chemistry, possibly due to rising CO2. Aluminum and titanium levels vary with the strength of the NAO. The highest concentrations occur at the time of strong positive NOA when there is large amount of sediment transported off the deserts of North Africa. This relationship is particularly strong in the coral from the Cape Verde Islands. Along the eastern seaboard of the Atlantic, the relationship is not as pronounced but still observable. Nutrients and anthropogenic trace metals, such as zinc, lead, and mercury appear to correlate with local conditions and show a weak correspondence to the El Nino as it affects south Florida. Boron variation is directly related to the high-density bands of the corals. The long-term record of boron

  10. Forest productivity in southwestern Europe is controlled by coupled North Atlantic and Atlantic Multidecadal Oscillations.

    Science.gov (United States)

    Madrigal-González, Jaime; Ballesteros-Cánovas, Juan A; Herrero, Asier; Ruiz-Benito, Paloma; Stoffel, Markus; Lucas-Borja, Manuel E; Andivia, Enrique; Sancho-García, Cesar; Zavala, Miguel A

    2017-12-20

    The North Atlantic Oscillation (NAO) depicts annual and decadal oscillatory modes of variability responsible for dry spells over the European continent. The NAO therefore holds a great potential to evaluate the role, as carbon sinks, of water-limited forests under climate change. However, uncertainties related to inconsistent responses of long-term forest productivity to NAO have so far hampered firm conclusions on its impacts. We hypothesize that, in part, such inconsistencies might have their origin in periodical sea surface temperature anomalies in the Atlantic Ocean (i.e., Atlantic Multidecadal Oscillation, AMO). Here we show strong empirical evidence in support of this hypothesis using 120 years of periodical inventory data from Iberian pine forests. Our results point to AMO + NAO + and AMO - NAO - phases as being critical for forest productivity, likely due to decreased winter water balance and abnormally low winter temperatures, respectively. Our findings could be essential for the evaluation of ecosystem functioning vulnerabilities associated with increased climatic anomalies under unprecedented warming conditions in the Mediterranean.

  11. Global warming

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Canada's Green Plan strategy for dealing with global warming is being implemented as a multidepartmental partnership involving all Canadians and the international community. Many of the elements of this strategy are built on an existing base of activities predating the Green Plan. Elements of the strategy include programs to limit emissions of greenhouse gases, such as initiatives to encourage more energy-efficient practices and development of alternate fuel sources; studies and policy developments to help Canadians prepare and adapt to climate change; research on the global warming phenomenon; and stimulation of international action on global warming, including obligations arising out of the Framework Convention on Climate Change. All the program elements have been approved, funded, and announced. Major achievements to date are summarized, including improvements in the Energy Efficiency Act, studies on the socioeconomic impacts of global warming, and participation in monitoring networks. Milestones associated with the remaining global warming initiatives are listed

  12. Sustained climate warming drives declining marine biological productivity

    Science.gov (United States)

    Moore, J. Keith; Fu, Weiwei; Primeau, Francois; Britten, Gregory L.; Lindsay, Keith; Long, Matthew; Doney, Scott C.; Mahowald, Natalie; Hoffman, Forrest; Randerson, James T.

    2018-03-01

    Climate change projections to the year 2100 may miss physical-biogeochemical feedbacks that emerge later from the cumulative effects of climate warming. In a coupled climate simulation to the year 2300, the westerly winds strengthen and shift poleward, surface waters warm, and sea ice disappears, leading to intense nutrient trapping in the Southern Ocean. The trapping drives a global-scale nutrient redistribution, with net transfer to the deep ocean. Ensuing surface nutrient reductions north of 30°S drive steady declines in primary production and carbon export (decreases of 24 and 41%, respectively, by 2300). Potential fishery yields, constrained by lower–trophic-level productivity, decrease by more than 20% globally and by nearly 60% in the North Atlantic. Continued high levels of greenhouse gas emissions could suppress marine biological productivity for a millennium.

  13. Warm Water Entrainment Impacts and Environmental Life Cycle Assessment of a Proposed Ocean Thermal Energy Conversion Pilot Plant Offshore Oahu, Hawaii

    Science.gov (United States)

    Hauer, Whitney Blanchard

    Ocean thermal energy conversion (OTEC) is a marine renewable energy technology that uses the temperature difference of large volumes of cold deep and warm surface seawater in tropical regions to generate electricity. One anticipated environmental impact of OTEC operations is the entrainment and subsequent mortality of ichthyoplankton (fish eggs and larvae) from the withdrawal of cold and warm seawater. The potential ichthyoplankton loss from the warm water intake was estimated for a proposed 10 MW OTEC pilot plant offshore Oahu, HI based on ambient vertical distribution data. The estimated losses due to entrainment from the warm water intake were 8.418E+02 larvae/1000 m3, 3.26E+06 larvae/day, and 1.19E+09 larvae/year. The potential entrained larvae/year is 1.86 X greater than at the Kahe Generating Station (Kapolei, HI), a 582 MW oil-fired power plant. Extrapolating to age-1 equivalence (9.2E+02 and 2.9E+02 yellowfin and skipjack tuna, respectively), the estimated yearly losses from warm water entrainment of yellowfin and skipjack tuna fish eggs and larvae represent 0.25-0.26 % and 0.09-0.11 % of Hawaii's commercial yellowfin and skipjack tuna industry in 2011 and 2012. An environmental life cycle assessment (LCA) was developed for the proposed OTEC plant operating for 20 and 40 years with availability factors of 0.85, 0.95, and 1.0 to determine the global warming potential (GWP) and cumulative energy demand (CED) impacts. For a 20 year operational OTEC plant, the GWP, CED, energy return on investment (EROI), and energy payback time (EPBT) ranged from 0.047 to 0.055 kg CO2eq/kWh, 0.678 to 0.798 MJ/kWh, 4.51 to 5.31 (unitless), and 3.77 to 4.43 years, respectively. For a 40 year operational OTEC plant, the GWP, CED, EROI, and EBPT ranged from 0.036 to 0.043 kg CO2eq/kWh, 0.527 to 0.620 MJ/kWh, 5.81 to 6.83 (unitless), and 5.85 to 6.89 years, respectively. The GWP impacts are within the range of renewable energy technologies and less than conventional electricity

  14. Assessing Phytoplankton Nutritional Status and Potential Impact of Wet Deposition in Seasonally Oligotrophic Waters of the Mid-Atlantic Bight

    Science.gov (United States)

    Sedwick, P. N.; Bernhardt, P. W.; Mulholland, M. R.; Najjar, R. G.; Blumen, L. M.; Sohst, B. M.; Sookhdeo, C.; Widner, B.

    2018-04-01

    To assess phytoplankton nutritional status in seasonally oligotrophic waters of the southern Mid-Atlantic Bight, and the potential for rain to stimulate primary production in this region during summer, shipboard bioassay experiments were performed using natural seawater and phytoplankton collected north and south of the Gulf Stream. Bioassay treatments comprised iron, nitrate, iron + nitrate, iron + nitrate + phosphate, and rainwater. Phytoplankton growth was inferred from changes in chlorophyll a, inorganic nitrogen, and carbon-13 uptake, relative to unamended control treatments. Results indicated the greatest growth stimulation by iron + nitrate + phosphate, intermediate growth stimulation by rainwater, modest growth stimulation by nitrate and iron + nitrate, and no growth stimulation by iron. Based on these data and analysis of seawater and atmospheric samples, nitrogen was the proximate limiting nutrient, with a secondary limitation imposed by phosphorus. Our results imply that summer rain events increase new production in these waters by contributing nitrogen and phosphorus, with the availability of the latter setting the upper limit on rain-stimulated new production.

  15. Large-scale deep-water seafloor mapping from the Rockall to the Hatton basins, NE Atlantic

    Science.gov (United States)

    Monteys, X.; Thébaudeau, B.; Murcia, C.; Duncan, N.

    2016-02-01

    Multibeam data acquired in 2000 and 2001 during the Irish National Seabed Survey (INSS) are used for the first detailed investigation of the seabed geomorphology and sediment type in the Hatton-Rockall basin area of the North East Atlantic Ocean, covering an area of approximately 80,000 km². The original multibeam survey produced bathymetric and backscatter datasets that allowed the creation of a Digital Terrain Models of approximately 50 m in resolution in water depths between 500 and 3500 m. Near-surface sediments for the entire region haven been classified using features derived from multibeam angular backscatter data (12kHz) and robust unsupervised clustering techniques. Additionally, sub bottom data imaging the shallow stratigraphy and geomagnetic measurements collected at the time of the MBES survey are combined to further characterise some of the features identified. The features presented in detail include parts of the Hatton and Gardar contourite drifts, volcanic mounds identified by their morphology and magnetic signature, deep-water coral mounds, iceberg scours as well as canyons, gullies and escarpments along and down the slopes of the banks and mounds. This study highlights for the first time the variety and complexity of the seafloor present at the seabed in the Irish Hatton-Rockall basin area

  16. North Atlantic variability and its links to European climate over the last 3000 years.

    Science.gov (United States)

    Moffa-Sánchez, Paola; Hall, Ian R

    2017-11-23

    The subpolar North Atlantic is a key location for the Earth's climate system. In the Labrador Sea, intense winter air-sea heat exchange drives the formation of deep waters and the surface circulation of warm waters around the subpolar gyre. This process therefore has the ability to modulate the oceanic northward heat transport. Recent studies reveal decadal variability in the formation of Labrador Sea Water. Yet, crucially, its longer-term history and links with European climate remain limited. Here we present new decadally resolved marine proxy reconstructions, which suggest weakened Labrador Sea Water formation and gyre strength with similar timing to the centennial cold periods recorded in terrestrial climate archives and historical records over the last 3000 years. These new data support that subpolar North Atlantic circulation changes, likely forced by increased southward flow of Arctic waters, contributed to modulating the climate of Europe with important societal impacts as revealed in European history.

  17. Carbon dioxide flux and net primary production of a boreal treed bog: Responses to warming and water-table-lowering simulations of climate change

    Science.gov (United States)

    Munir, T. M.; Perkins, M.; Kaing, E.; Strack, M.

    2015-02-01

    Midlatitude treed bogs represent significant carbon (C) stocks and are highly sensitive to global climate change. In a dry continental treed bog, we compared three sites: control, recent (1-3 years; experimental) and older drained (10-13 years), with water levels at 38, 74 and 120 cm below the surface, respectively. At each site we measured carbon dioxide (CO2) fluxes and estimated tree root respiration (Rr; across hummock-hollow microtopography of the forest floor) and net primary production (NPP) of trees during the growing seasons (May to October) of 2011-2013. The CO2-C balance was calculated by adding the net CO2 exchange of the forest floor (NEff-Rr) to the NPP of the trees. From cooler and wetter 2011 to the driest and the warmest 2013, the control site was a CO2-C sink of 92, 70 and 76 g m-2, the experimental site was a CO2-C source of 14, 57 and 135 g m-2, and the drained site was a progressively smaller source of 26, 23 and 13 g CO2-C m-2. The short-term drainage at the experimental site resulted in small changes in vegetation coverage and large net CO2 emissions at the microforms. In contrast, the longer-term drainage and deeper water level at the drained site resulted in the replacement of mosses with vascular plants (shrubs) on the hummocks and lichen in the hollows leading to the highest CO2 uptake at the drained hummocks and significant losses in the hollows. The tree NPP (including above- and below-ground growth and litter fall) in 2011 and 2012 was significantly higher at the drained site (92 and 83 g C m-2) than at the experimental (58 and 55 g C m-2) and control (52 and 46 g C m-2) sites. We also quantified the impact of climatic warming at all water table treatments by equipping additional plots with open-top chambers (OTCs) that caused a passive warming on average of ~ 1 °C and differential air warming of ~ 6 °C at midday full sun over the study years. Warming significantly enhanced shrub growth and the CO2 sink function of the drained

  18. Carbonate system in the water masses of the Southeast Atlantic sector of the Southern Ocean during February and March 2008

    Directory of Open Access Journals (Sweden)

    M. González-Dávila

    2011-05-01

    Full Text Available Carbonate system variables were measured in the South Atlantic sector of the Southern Ocean along a transect from South Africa to the southern limit of the Antarctic Circumpolar Current (ACC from February to March 2008. Eddies detached from the retroflection of the Agulhas Current increased the gradients observed along the fronts. Minima in the fugacity of CO2, fCO2, and maxima in pH on either side of the frontal zone were observed, noting that within the frontal zone fCO2 reached maximum values and pH was at a minimum.

    Vertical distributions of water masses were described by their carbonate system properties and their relationship to CFC concentrations. Upper Circumpolar Deep Water (UCDW and Lower Circumpolar Deep Water (LCDW offered pHT,25 values of 7.56 and 7.61, respectively. The UCDW also had higher concentrations of CFC-12 (>0.2 pmol kg−1 as compared to deeper waters, revealing that UCDW was mixed with recently ventilated waters. Calcite and aragonite saturation states (Ω were also affected by the presence of these two water masses with high carbonate concentrations. The aragonite saturation horizon was observed at 1000 m in the subtropical area and north of the Subantarctic Front. At the position of the Polar Front, and under the influence of UCDW and LCDW, the aragonite saturation horizon deepened from 800 m to 1500 m at 50.37° S, and reached 700 m south of 57.5° S. High latitudes proved to be the most sensitive areas to predicted anthropogenic carbon increase. Buffer coefficients related to changes in [CO2], [H+] and Ω with changes in dissolved inorganic carbon (CT and total alkalinity (AT offered minima values in the Antarctic Intermediate Water and UCDW layers. These coefficients suggest that a small increase in CT will sharply decrease the status of pH and carbonate saturation

  19. Specific absorption and backscatter coefficient signatures in southeastern Atlantic coastal waters

    Science.gov (United States)

    Bostater, Charles R., Jr.

    1998-12-01

    Measurements of natural water samples in the field and laboratory of hyperspectral signatures of total absorption and reflectance were obtained using long pathlength absorption systems (50 cm pathlength). Water was sampled in Indian River Lagoon, Banana River and Port Canaveral, Florida. Stations were also occupied in near coastal waters out to the edge of the Gulf Stream in the vicinity of Kennedy Space Center, Florida and estuarine waters along Port Royal Sound and along the Beaufort River tidal area in South Carolina. The measurements were utilized to calculate natural water specific absorption, total backscatter and specific backscatter optical signatures. The resulting optical cross section signatures suggest different models are needed for the different water types and that the common linear model may only appropriate for coastal and oceanic water types. Mean particle size estimates based on the optical cross section, suggest as expected, that particle size of oceanic particles are smaller than more turbid water types. The data discussed and presented are necessary for remote sensing applications of sensors as well as for development and inversion of remote sensing algorithms.

  20. Linking benthic hydrodynamics and cold-water coral occurrences: A high-resolution model study at three cold-water coral provinces in the NE Atlantic

    Science.gov (United States)

    Mohn, Christian; Rengstorf, Anna; White, Martin; Duineveld, Gerard; Mienis, Furu; Soetaert, Karline; Grehan, Anthony

    2014-03-01

    Observations from numerous cold-water coral locations in the NE Atlantic show energetic near-bottom flow dynamics along the European continental margin at individual coral mounds and mound clusters. Dynamics are largely controlled by tide-topography interaction generating and enhancing periodic motions such as trapped waves, freely propagating internal tides and internal hydraulic jumps. In this study, linkages between key abiotic parameters and cold water coral occurrences are explored across entire cold-water coral mound provinces using an integrated modelling and observational approach. The 3-D ocean circulation model ROMS-AGRIF was applied to simulate near-bottom hydrodynamic conditions at three provinces in the NE Atlantic (Logachev mounds, Arc mounds and Belgica mounds) adopting a nested model setup with a central grid resolution of 250 m. Simulations were carried out with a focus on accurate high-resolution topography and tidal forcing. The central model bathymetry was taken from high-resolution INSS (Irish National Seabed Survey) seafloor mapping data. The model was integrated over a full one-year reference period starting from the 1st January 2010. Interannual variability was not considered. Tidal forcing was obtained from a global solution of the Oregon State University (OSU) inverse tidal model. Modelled fields of benthic currents were validated against available independent in situ observations. Coral assemblage patterns (presence and absence locations) were obtained from benthic surveys of the EU FP7 CoralFISH programme and supplemented by data from additional field surveys. Modelled near-bottom currents, temperature and salinity were analysed for a 1-month subset (15th April to 15th May 2010) corresponding to the main CoralFISH survey period. The model results show intensified near-bottom currents in areas where living corals are observed by contrast with coral absence and random background locations. Instantaneous and time-mean current speeds at

  1. Silicate:nitrate ratios of upwelled waters control the phytoplankton community sustained by mesoscale eddies in sub-tropical North Atlantic and Pacific

    Directory of Open Access Journals (Sweden)

    T. S. Bibby

    2011-03-01

    Full Text Available Mesoscale eddies in sub-tropical gyres physically perturb the water column and can introduce macronutrients to the euphotic zone, stimulating a biological response in which phytoplankton communities can become dominated by large phytoplankton. Mesoscale eddies may therefore be important in driving export in oligotrophic regions of the modern ocean. However, the character and magnitude of the biological response sustained by eddies is variable. Here we present data from mesoscale eddies in the Sargasso Sea (Atlantic and the waters off Hawai'i (Pacific, alongside mesoscale events that affected the Bermuda Atlantic Time-Series Study (BATS over the past decade. From this analysis, we suggest that the phytoplankton community structure sustained by mesoscale eddies is predetermined by the relative abundance of silicate over nitrate (Si* in the upwelled waters. We present data that demonstrate that mode-water eddies (MWE in the Sargasso Sea upwell locally formed waters with relatively high Si* to the euphotic zone, and that cyclonic eddies in the Sargasso Sea introduce waters with relatively low Si*, a signature that originated in the iron-limited Southern Ocean. We propose that this phenomenon can explain the observed dominance of the phytoplankton community by large-diatom species in MWE and by small prokaryotic phytoplankton in cyclonic features. In contrast to the Atlantic, North Pacific Intermediate Water (NPIW with high Si* may influence the cyclonic eddies in waters off Hawai'i, which also appear capable of sustaining diatom populations. These observations suggest that the structure of phytoplankton communities sustained by eddies may be related to the chemical composition of the upwelled waters in addition to the physical nature of the eddy.

  2. New direct estimates of Iceland-Scotland Overflow Water transport through the Charlie-Gibbs Fracture Zone and its relationship to the North Atlantic Current

    Science.gov (United States)

    Bower, Amy; Furey, Heather; Xu, Xiaobiao

    2015-04-01

    Detailed observations of the pathways, transports and water properties of dense overflows associated with the Atlantic Meridional Overturning Circulation (AMOC) provide critical benchmarks for climate models and mixing parameterizations. A recent two-year time series from eight moorings offers the first long-term simultaneous observations of the hydrographic properties and transport of Iceland-Scotland Overflow Water (ISOW) flowing westward through the Charlie-Gibbs Fracture Zone (CGFZ), a major deep gap in the Mid-Atlantic Ridge (MAR) connecting the eastern and western basins of the North Atlantic. In addition, current meters up to 500-m depth and satellite altimetry allow us to investigate the overlying North Atlantic Current (NAC) as a source of ISOW transport variability. Using the isohaline 34.94 to define the ISOW layer, the two year mean and standard deviation of ISOW transport was -1.7 ± 1.5 Sv, compared to -2.4 ± 3.0 Sv reported by Saunders for a 13-month period in 1988-1989 using the same isohaline. Differences in the two estimates are partly explained by limitations of the Saunders array, but more importantly reflect the strong low-frequency variability in ISOW transport through CGFZ (which includes complete reversals). Both the observations and output from a multi-decadal simulation of the North Atlantic using the Hybrid Coordinate Ocean Model (HYCOM) forced with interannually varying wind and buoyancy fields indicate a strong positive correlation between ISOW transport and the strength of the NAC through the CGFZ. This result raises new questions regarding the interaction of the upper and lower limbs of the AMOC, downstream propagation of ISOW transport variability in the Deep Western Boundary Current and alternative pathways of ISOW across the MAR.

  3. Temperature profile and water depth data collected from ANGO and other platforms using XBT casts in the TOGA Area - Atlantic from 14 February 1992 to 13 April 1993 (NODC Accession 9400047)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using XBT casts from the ANGO and other platforms in the TOGA - Atlantic Ocean. Data were collected from 14...

  4. Temperature profile and water depth collected from ZAMBEZE and other platforms using BT and XBT casts in the Atlantic Ocean from 21 July 1981 to 02 December 1985 (NODC Accession 8600293)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the ZAMBEZE and other platforms in the Northeast / Southwest Atlantic Ocean. Data...

  5. Temperature profile and water depth data collected from USCGC HARRIOT LANE using BT and XBT casts in the Northwest Atlantic Ocean from 01 December 1987 to 05 January 1988 (NODC Accession 8800015)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC HARRIOT LANE in the Northwest Atlantic Ocean. Data were collected from...

  6. Temperature profile and water depth data collected from USCGC HARRIET LANE using BT and XBT casts in the Northwest Atlantic Ocean from 21 July 1988 to 18 August 1988 (NODC Accession 8800256)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC HARRIET LANE in the Northwest Atlantic Ocean. Data were collected from...

  7. Temperature profile and water depth data collected from USCGC HARRIOT LANE using BT and XBT casts in the Northwest Atlantic Ocean and Caribbean Sea from 30 April 1988 to 31 May 1988 (NODC Accession 8800173)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC HARRIOT LANE in the Northwest Atlantic Ocean and Caribbean Sea. Data...

  8. Temperature profile and water depth data collected from USCGC HARRIOT LANE using BT and XBT casts in the Northwest Atlantic Ocean from 09 March 1988 to 10 March 1988 (NODC Accession 8800094)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC Harriot Lane in the Northwest Atlantic Ocean. Data were collected from...

  9. Water physics and chemistry data from moored current meter and bottle casts in the Northwest Atlantic Ocean as part of the North East Monitoring Program (NEMP) project, 1980-09-02 to 1980-09-06 (NODC Accession 8100628)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected using moored current meter and bottle casts in the Northwest Atlantic Ocean from September 2, 1980 to September 6,...

  10. Temperature profile and water depth data collected from AUSTRALIA STAR and other platforms using XBT casts in the TOGA Area - Atlantic and Pacific Ocean from 05 October 1989 to 21 December 1992 (NODC Accession 9400035)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using XBT casts from the AUSTRALIA STAR and other platforms in the TOGA Area - Atlantic and Pacific Ocean,...

  11. Temperature profile and water depth data collected from USS ROBERT G. BRADLEY using BT and XBT casts in the NE/NW Atlantic Ocean and other seas from 03 May 1988 to 31 May 1988 (NODC Accession 8800213)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS ROBERT G. BRADLEY in the Northwest / Northeast Atlantic Ocean, Arabian...

  12. Temperature profile and water depth data from BT and XBT casts in the Atlantic Ocean from USCGC POLAR SEA from 14 December 1983 to 06 May 1984 (NODC Accession 8600108)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC POLAR SEA in the Atlantic Ocean. Data were collected from 14 December...

  13. Temperature profile and water depth data collected from USS JOHN RODGERS using BT and XBT casts in the NE/NW Atlantic Ocean and other seas from 03 August 1988 to 03 October 1988 (NODC Accession 8900041)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS JOHN RODGERS in the Northeast / Northwest Atlantic Ocean, Ionian Sea,...

  14. Water physics and chemistry data from moored current meter and bottle casts in the Northwest Atlantic Ocean as part of the North East Monitoring Program (NEMP) project, 1982-05-28 to 1982-06-04 (NODC Accession 8300008)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected using moored current meter and bottle casts in the Northwest Atlantic Ocean from May 28, 1982 to June 4, 1982. Data...

  15. Temperature profile and water depth collected from BT and XBT casts in the Northwest Atlantic Ocean from SEDCO BP 471 from 03 November 1985 to 23 December 1985 (NODC Accession 8600138)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the SEDCO BP 471 in the Northwest Atlantic Ocean. Data were collected from 03...

  16. Cold Water, Warm Ice?

    Science.gov (United States)

    Yang, Li-Hsuan

    2012-01-01

    This article describes engaging students in two simple observations to address the concepts of changes of states, heat, temperature, and molecular potential and kinetic energy. It also discusses how these concepts can enable students to further explore and understand interesting and significant phenomena and research in multiple areas of science.…

  17. Eight-month of physical training in warm water improves physical and mental health in women with fibromyalgia: a randomized controlled trial

    OpenAIRE

    Tomas-Carus, Pablo; Gusi, Narcis; Häkkinen, Arja; Häkkinen, Keijo; Leal, Alejo; Ortega-Alonso, Alfredo

    2008-01-01

    OBJECTIVE: To evaluate the feasibility of 8 months of supervised exercise therapy in warm water and its effects on the impact of fibromyalgia on physical and mental health and physical fitness in affected women. METHODS: Thirty women with fibromyalgia were randomly assigned to an exercise therapy group (n = 15) or a control group (inactive) (n = 15). The impact of fibromyalgia on physical and mental health was assessed using the Fibromyalgia Impact Questionnaire and the anxiety state with...

  18. Development of temporal trends of radioactivity in benthic organisms and in water from the deep sea (Atlantic)

    International Nuclear Information System (INIS)

    Kanisch, G.; Kellermann, H.-J.; Vobach, M.; Krueger, A.

    2003-01-01

    Since 20 years the Federal Research Centre for Fisheries is performing radioecological studies in the deep sea of the Northeast Atlantic, especially in the area north-west of Spain used for dumping of radioactive waste until 1982. Until 1998/2000, in Benthos some decrease was observed for 137 Cs, however, almost not for 238 Pu, 239,240 Pu and 241 Am. In the dumpsite area the ratio 238 Pu/ 239,240 Pu, about 0.072, showed higher values than in comparison sites, about 0,044. Alpha spectrometric measurements of the atom based ratio 240 Pu/ 239 Pu in Benthos, due to slight deviations from the global fallout value of 0.18, indicated a special impact of the ''Nevada Test Site'' fallout. In rat-tailed fish (Macrouridae) from the deep sea 137Cs decreased since 1989 with an effective half-live of 14.5 years, comparable to that of 16.2 years in the surface water. Related to the concentration in the surface water a 137 Cs concentration factor of 83 was obtained. It is concluded that the dominant source for 137 Cs in deep sea fish is the global fallout. For plutonium isotopes measured in sea water samples from the deep the values of 238 Pu/ 239,240 Pu and 238 Pu, being higher for the dumpsite area, were interpreted as impact of leaking radioactive drums. For this leakage acting as a plutonium source a 238 Pu/ 239,240 Pu ratio of 0.17 was estimated. However, the total plutonium inventory in the deep sea thereby increased by only about 20 %. (orig.)

  19. Spatial–temporal changes in runoff and terrestrial ecosystem water retention under 1.5 and 2 °C warming scenarios across China

    Directory of Open Access Journals (Sweden)

    R. Zhai

    2018-06-01

    Full Text Available The Paris Agreement set a long-term temperature goal of holding the global average temperature increase to below 2.0 °C above pre-industrial levels, pursuing efforts to limit this to 1.5 °C; it is therefore important to understand the impacts of climate change under 1.5 and 2.0 °C warming scenarios for climate adaptation and mitigation. Here, climate scenarios from four global circulation models (GCMs for the baseline (2006–2015, 1.5, and 2.0 °C warming scenarios (2106–2115 were used to drive the validated Variable Infiltration Capacity (VIC hydrological model to investigate the impacts of global warming on runoff and terrestrial ecosystem water retention (TEWR across China at a spatial resolution of 0.5°. This study applied ensemble projections from multiple GCMs to provide more comprehensive and robust results. The trends in annual mean temperature, precipitation, runoff, and TEWR were analyzed at the grid and basin scale. Results showed that median change in runoff ranged from 3.61 to 13.86 %, 4.20 to 17.89 %, and median change in TEWR ranged from −0.45 to 6.71 and −3.48 to 4.40 % in the 10 main basins in China under 1.5 and 2.0 °C warming scenarios, respectively, across all four GCMs. The interannual variability of runoff increased notably in areas where it was projected to increase, and the interannual variability increased notably from the 1.5 to the 2.0 °C warming scenario. In contrast, TEWR would remain relatively stable, the median change in standard deviation (SD of TEWR ranged from −10 to 10 % in about 90 % grids under 1.5 and 2.0 °C warming scenarios, across all four GCMs. Both low and high runoff would increase under the two warming scenarios in most areas across China, with high runoff increasing more. The risks of low and high runoff events would be higher under the 2.0 than under the 1.5 °C warming scenario in terms of both extent and intensity. Runoff was significantly positively

  20. Spatial-temporal changes in runoff and terrestrial ecosystem water retention under 1.5 and 2 °C warming scenarios across China

    Science.gov (United States)

    Zhai, Ran; Tao, Fulu; Xu, Zhihui

    2018-06-01

    The Paris Agreement set a long-term temperature goal of holding the global average temperature increase to below 2.0 °C above pre-industrial levels, pursuing efforts to limit this to 1.5 °C; it is therefore important to understand the impacts of climate change under 1.5 and 2.0 °C warming scenarios for climate adaptation and mitigation. Here, climate scenarios from four global circulation models (GCMs) for the baseline (2006-2015), 1.5, and 2.0 °C warming scenarios (2106-2115) were used to drive the validated Variable Infiltration Capacity (VIC) hydrological model to investigate the impacts of global warming on runoff and terrestrial ecosystem water retention (TEWR) across China at a spatial resolution of 0.5°. This study applied ensemble projections from multiple GCMs to provide more comprehensive and robust results. The trends in annual mean temperature, precipitation, runoff, and TEWR were analyzed at the grid and basin scale. Results showed that median change in runoff ranged from 3.61 to 13.86 %, 4.20 to 17.89 %, and median change in TEWR ranged from -0.45 to 6.71 and -3.48 to 4.40 % in the 10 main basins in China under 1.5 and 2.0 °C warming scenarios, respectively, across all four GCMs. The interannual variability of runoff increased notably in areas where it was projected to increase, and the interannual variability increased notably from the 1.5 to the 2.0 °C warming scenario. In contrast, TEWR would remain relatively stable, the median change in standard deviation (SD) of TEWR ranged from -10 to 10 % in about 90 % grids under 1.5 and 2.0 °C warming scenarios, across all four GCMs. Both low and high runoff would increase under the two warming scenarios in most areas across China, with high runoff increasing more. The risks of low and high runoff events would be higher under the 2.0 than under the 1.5 °C warming scenario in terms of both extent and intensity. Runoff was significantly positively correlated to precipitation, while increase in maximum

  1. Simulated variability of the Atlantic meridional overturning circulation

    Science.gov (United States)

    Bentsen, M.; Drange, H.; Furevik, T.; Zhou, T.

    To examine the multi-annual to decadal scale variability of the Atlantic Meridional Overturning Circulation (AMOC) we conducted a four-member ensemble with a daily reanalysis forced, medium-resolution global version of the isopycnic coordinate ocean model MICOM, and a 300-years integration with the fully coupled Bergen Climate Model (BCM). The simulations of the AMOC with both model systems yield a long-term mean value of 18 Sv and decadal variability with an amplitude of 1-3 Sv. The power spectrum of the inter-annual to decadal scale variability of the AMOC in BCM generally follows the theoretical red noise spectrum, with indications of increased power near the 20-years period. Comparison with observational proxy indices for the AMOC, e.g. the thickness of the Labrador Sea Water, the strength of the baroclinic gyre circulation in the North Atlantic Ocean, and the surface temperature anomalies along the mean path of the Gulf Stream, shows similar trends and phasing of the variability, indicating that the simulated AMOC variability is robust and real. Mixing indices have been constructed for the Labrador, the Irminger and the Greenland-Iceland-Norwegian (GIN) seas. While convective mixing in the Labrador and the GIN seas are in opposite phase, and linked to the NAO as observations suggest, the convective mixing in the Irminger Sea is in phase with or leads the Labrador Sea. Newly formed deep water is seen as a slow, anomalous cold and fresh, plume flowing southward along the western continental slope of the Atlantic Ocean, with a return flow of warm and saline water on the surface. In addition, fast-travelling topographically trapped waves propagate southward along the continental slope towards equator, where they go east and continue along the eastern rim of the Atlantic. For both types of experiments, the Northern Hemisphere sea level pressure and 2 m temperature anomaly patterns computed based on the difference between climate states with strong and weak AMOC

  2. The Effect of Dissolved Polyunsaturated Aldehydes on Microzooplankton Growth Rates in the Chesapeake Bay and Atlantic Coastal Waters

    Directory of Open Access Journals (Sweden)

    Peter J. Lavrentyev

    2015-05-01

    Full Text Available Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA. Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, especially at the higher concentrations, but there were pronounced differences in response among common planktonic species. For example, the growth of Codonella sp., Leegaardiella sol, Prorodon sp., and Gyrodinium spirale was impaired at 2 nM, whereas Strombidium conicum, Cyclotrichium gigas, and Gymnodinium sp. were not affected even at 20 nM. These results indicate that PUA can induce changes in microzooplankton dynamics and species composition.

  3. The Effect of Dissolved Polyunsaturated Aldehydes on Microzooplankton Growth Rates in the Chesapeake Bay and Atlantic Coastal Waters

    Science.gov (United States)

    Lavrentyev, Peter J.; Franzè, Gayantonia; Pierson, James J.; Stoecker, Diane K.

    2015-01-01

    Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA). Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, especially at the higher concentrations, but there were pronounced differences in response among common planktonic species. For example, the growth of Codonella sp., Leegaardiella sol, Prorodon sp., and Gyrodinium spirale was impaired at 2 nM, whereas Strombidium conicum, Cyclotrichium gigas, and Gymnodinium sp. were not affected even at 20 nM. These results indicate that PUA can induce changes in microzooplankton dynamics and species composition. PMID:25955757

  4. Biological validation of physical coastal waters classification along the NE Atlantic region based on rocky macroalgae distribution

    Science.gov (United States)

    Ramos, Elvira; Puente, Araceli; Juanes, José Antonio; Neto, João M.; Pedersen, Are; Bartsch, Inka; Scanlan, Clare; Wilkes, Robert; Van den Bergh, Erika; Ar Gall, Erwan; Melo, Ricardo

    2014-06-01

    A methodology to classify rocky shores along the North East Atlantic (NEA) region was developed. Previously, biotypes and the variability of environmental conditions within these were recognized based on abiotic data. A biological validation was required in order to support the ecological meaning of the physical typologies obtained. A database of intertidal macroalgae species occurring in the coastal area between Norway and the South Iberian Peninsula was generated. Semi-quantitative abundance data of the most representative macroalgal taxa were collected in three levels: common, rare or absent. Ordination and classification multivariate analyses revealed a clear latitudinal gradient in the distribution of macroalgae species resulting in two distinct groups: one northern and one southern group, separated at the coast of Brittany (France). In general, the results based on biological data coincided with the results based on physical characteristics. The ecological meaning of the coastal waters classification at a broad scale shown in this work demonstrates that it can be valuable as a practical tool for conservation and management purposes.

  5. Uranium in pore waters from North Atlantic (GME and Southern Nares Abyssal Plain) sediments

    International Nuclear Information System (INIS)

    Santschi, P.H.; Bajo, C.; Mantovani, M.; Orciuolo, D.; Cranston, R.E.; Bruno, J.

    1988-01-01

    Here we report the measurement of low uranium concentrations in composite pore-water samples from the uppermost 20-30 m of deep-sea abyssal plain sediments from the Great Meteor East and Southern Nares Abyssal Plains Area. Many values are the lowest uranium concentrations ever measured in the pore waters of deep-sea sediments. Our lowest value, 0.05 ± 0.01 p.p.b., is orders of magnitude lower than the predicted solubility of U0 2 or U 4 0 9 . The uranium concentrations obtained from both sites correlate closely with measured redox potentials in the sediments. The low mobility of uranium in pore waters from turbiditic deep-sea abyssal plain sediments, which can be deduced from these measurements, has important implications for the sub-seabed disposal of high-level radioactive waste, and for marine geochemistry of uranium. (author)

  6. Stream water temperature limits occupancy of salamanders in mid-Atlantic protected areas

    Science.gov (United States)

    Grant, Evan H. Campbell; Wiewel, Amber N. M.; Rice, Karen C.

    2014-01-01

    Stream ecosystems are particularly sensitive to urbanization, and tolerance of water-quality parameters is likely important to population persistence of stream salamanders. Forecasted climate and landscape changes may lead to significant changes in stream flow, chemical composition, and temperatures in coming decades. Protected areas where landscape alterations are minimized will therefore become increasingly important for salamander populations. We surveyed 29 streams at three national parks in the highly urbanized greater metropolitan area of Washington, DC. We investigated relationships among water-quality variables and occupancy of three species of stream salamanders (Desmognathus fuscus, Eurycea bislineata, and Pseudotriton ruber). With the use of a set of site-occupancy models, and accounting for imperfect detection, we found that stream-water temperature limits salamander occupancy. There was substantial uncertainty about the effects of the other water-quality variables, although both specific conductance (SC) and pH were included in competitive models. Our estimates of occupancy suggest that temperature, SC, and pH have some importance in structuring stream salamander distribution.

  7. Water velocity in commercial RAS culture tanks for Atlantic salmon smolt production

    Science.gov (United States)

    An optimal flow domain in culture tanks is vital for fish growth and welfare. This paper presents empirical data on rotational velocity and water quality in circular and octagonal tanks at two large commercial smolt production sites, with an approximate production rate of 1000 and 1300 ton smolt ann...

  8. Models of Plankton Community Changes during a Warm Water Anomaly in Arctic Waters Show Altered Trophic Pathways with Minimal Changes in Carbon Export

    Directory of Open Access Journals (Sweden)

    Maria Vernet

    2017-05-01

    Full Text Available Carbon flow through pelagic food webs is an expression of the composition, biomass and activity of phytoplankton as primary producers. In the near future, severe environmental changes in the Arctic Ocean are expected to lead to modifications of phytoplankton communities. Here, we used a combination of linear inverse modeling and ecological network analysis to study changes in food webs before, during, and after an anomalous warm water event in the eastern Fram Strait of the West Spitsbergen Current (WSC that resulted in a shift from diatoms to flagellates during the summer (June–July. The model predicts substantial differences in the pathways of carbon flow in diatom- vs. Phaeocystis/nanoflagellate-dominated phytoplankton communities, but relatively small differences in carbon export. The model suggests a change in the zooplankton community and activity through increasing microzooplankton abundance and the switching of meso- and macrozooplankton feeding from strict herbivory to omnivory, detritivory and coprophagy. When small cells and flagellates dominated, the phytoplankton carbon pathway through the food web was longer and the microbial loop more active. Furthermore, one step was added in the flow from phytoplankton to mesozooplankton, and phytoplankton carbon to higher trophic levels is available via detritus or microzooplankton. Model results highlight how specific changes in phytoplankton community composition, as expected in a climate change scenario, do not necessarily lead to a reduction in carbon export.

  9. WATER TEMPERATURE and Other Data from ALMIRANTE SALDANHA From SW Atlantic (limit-20 W) (NODC Accession 9700075)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Zooplankton, phytoplankton, chlorophyll, and other data were collected from net and bottle casts in the SW Atlantic Ocean (limit-20 W) from the Almirante Saldanha...

  10. PRESSURE - WATER and Other Data from KNORR From NW Atlantic (limit-40 W) from 19810401 to 19811019 (NODC Accession 8600274)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains CTD data from The Transient Tracers in the Ocean-North Atlantic study collected from April 1 to October 19, 1981. the data were collected on...

  11. Using shark biomarkers as tools for biomonitoring the health of atlantic waters

    Directory of Open Access Journals (Sweden)

    Luís Miguel Fonseca Alves

    2014-06-01

    The results obtained in this first biomarkers screening are promising as it allowed for a better understanding on how blue sharks deal with the intake and accumulation of different xenobiotics and which are the most suitable tissues for specific biomarker testing and more efficient biomonitoring. Lastly, this approach presents a potential to be adapted to other species which are also on top of food chains, providing an even more robust insight on the oceanic deep waters health status.

  12. North Atlantic Regional Water Resources Study. Appendix O. Fish and Wildlife.

    Science.gov (United States)

    1972-05-01

    free—flowing streams and na tural lakes, (2) adequate control of polut ion a t its sources , (3) construction of upstream water—storage facilities , (4...based upon existing environmental and resource conditions , e.g., existing extent and degrl’CCC of water polution , present species composition and...sedimen- tation , (5) radioactive substance , (6) heat from power and industrial plants , (7) toxic industrial effluents (8) toxic agricultural chemi

  13. Active Pacific meridional overturning circulation (PMOC) during the warm Pliocene.

    Science.gov (United States)

    Burls, Natalie J; Fedorov, Alexey V; Sigman, Daniel M; Jaccard, Samuel L; Tiedemann, Ralf; Haug, Gerald H

    2017-09-01

    An essential element of modern ocean circulation and climate is the Atlantic meridional overturning circulation (AMOC), which includes deep-water formation in the subarctic North Atlantic. However, a comparable overturning circulation is absent in the Pacific, the world's largest ocean, where relatively fresh surface waters inhibit North Pacific deep convection. We present complementary measurement and modeling evidence that the warm, ~400-ppmv (parts per million by volume) CO 2 world of the Pliocene supported subarctic North Pacific deep-water formation and a Pacific meridional overturning circulation (PMOC) cell. In Pliocene subarctic North Pacific sediments, we report orbitally paced maxima in calcium carbonate accumulation rate, with accompanying pigment and total organic carbon measurements supporting deep-ocean ventilation-driven preservation as their cause. Together with high accumulation rates of biogenic opal, these findings require vigorous bidirectional communication between surface waters and interior waters down to ~3 km in the western subarctic North Pacific, implying deep convection. Redox-sensitive trace metal data provide further evidence of higher Pliocene deep-ocean ventilation before the 2.73-Ma (million years) transition. This observational analysis is supported by climate modeling results, demonstrating that atmospheric moisture transport changes, in response to the reduced meridional sea surface temperature gradients of the Pliocene, were capable of eroding the halocline, leading to deep-water formation in the western subarctic Pacific and a strong PMOC. This second Northern Hemisphere overturning cell has important implications for heat transport, the ocean/atmosphere cycle of carbon, and potentially the equilibrium response of the Pacific to global warming.

  14. Surfactant control of air-sea gas exchange from North Sea coastal waters and the Atlantic Meridional Transect

    Science.gov (United States)

    Pereira, R.

    2016-02-01

    Suppression of gas transfer velocity (kw) by surfactants are well established, both in laboratory wind flumes and purposeful oceanic releases. However, the effects on kw of time and space varying concentrations of natural surfactant are inadequately studied. We have developed an automated gas exchange tank for simultaneous high precision measurement of kw in unmodified seawater samples. Here we present data from two studies along a coastal North Sea transect during 2012-2013 and the Atlantic Meridional Transect (AMT) 24 from September to November 2014. Measurements of surfactant activity (SA), CDOM absorbance and chlorophyll-a have enabled us to characterize the effects of variable amounts of natural surfactant on kw. North Sea coastal waters range in k660 (kw normalized to the value for CO2 in freshwater at 20oC) was 6.8-24.5 cm hr-1 (n=20), with the ranges of SA, total CDOM absorbance (200-450 nm) and chlorophyll-a measured in the surface microlayer (SML) of our seawater samples were 0.08-0.38 mg l-1 T-X-100, 0.13-4.7 and 0.09-1.54 µg l-1, respectively. The AMT k660 ranged from 7.0-23.9 cm hr-1 (n=22), with SA measured in the SML and subsurface water (SSW) of our seawater samples ranging from 0.15-1.08 mg l-1 T-X-100 and 0.07-0.43 mg l-1 T-X-100, respectively. Importantly, we found 12-45% (North Sea) and 1-43% (AMT) k660 suppression relative to Milli-Q water that relate to seasonal and spatial differences in SA. The North Sea demonstrated notable seasonal influences on k660 suppression that were related to CDOM absorbance and chlorophyll-a. The degree of k660 suppression was highest in summer consistent with k660 control by natural surfactant. The degree of k660 suppression decreased with distance offshore in the North Sea and displayed a strong relationship with SA (r2 = 0.51-0.64, p = 0.02, n = 20). The AMT demonstrated notable differences in k660 suppression between hemispheres and across the Longhurst Provinces but the overall relationship between k660

  15. [Comparison of novel infrared heating plates and conventional warm water plates for piglets' creep areas in farrowing pens].

    Science.gov (United States)

    Strauch-Sürken, L; Wendt, M

    2015-01-01

    On a conventionally managed piglet-producing farm, novel infrared (IR) heating plates for piglets in the farrowing pens were tested for their suitability and compared with common warm-water (WW) heating plates. In total, 134 litters (summer n = 82, winter n = 52) were investigated, which were housed on IR or WW heating plates, respectively, with or without an extra cover plate (groups 1-4). To determine the influence of the different heat sources, the wound healing after castration and tail docking, the umbilical regression and the weight gain of the piglets were investigated. Additionally, the lying behavior of the piglets and the position of the sows' udder at the time of farrowing were examined with regard to the heating plates. Furthermore, the energy consumption and costs were compared. The piglets housed on IR heating plates displayed better wound healing after castration and tail docking than the piglets housed on WW plates. The best results were obtained in piglets kept on IR heating plates with an extra cover plate. In addition, significant benefits were demonstrated for the usage of IR heating plates regarding umbilical regression. The piglets kept on IR heating plates had a slightly better weight gain in summer, whereas there were no differences between groups during winter. The lying behavior in the creep areas was similar in all groups. In general, with increasing age the percentage of time piglets spent in the lying position on the plates decreased. The percentage of time lying on the plates was higher in winter than in summer. At farrowing, 74.6% of all investigated sows directed their udder towards the heating plates. With the IR heating plates, this behavior occurred significantly more often. The energy consumption (kWh) per litter was significantly lower for the IR heating plates (electric power) both in winter and summer in comparison with the WW plates (gas). The energy costs were comparable in summer, but were higher for the IR heating plates

  16. Perfluorinated carboxylates and sulfonates in open ocean waters of the Pacific and Atlantic oceans

    Energy Technology Data Exchange (ETDEWEB)

    Taniyasu, Sachi; Yamashita, Nobuyoshi; Horii, Yuichi [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Kannan, K.; Sinclair, E. [Wadsworth Center, New York State Department of Health, Albany, CA (United States); Petrick, G. [Kiel Univ. (Germany). Inst. for Marine Research; Gamo, Toshitaka [Tokyo Univ. (Japan). Ocean Research Institute

    2004-09-15

    Environmentally stable perfluorinated compounds (PFCs) have appeared as a new class of global pollutants within the last four years. These compounds in general, and perfluorooctane sulfonate (PFOS) in particular, can elicit toxic effects in wildlife and humans. PFCs have unique physicochemical properties due to the highly persistent C-F bond of the non-polar moiety and exhibit a wide variety of volatility/ water solubility depending on the nature of the substituted polar moiety. Environmental kinetics of PFCs is very complex because of the unique characteristics and their wide applications in various products. It is clear that PFCs pollution is a global problem involving several international organizations such as OECD. We have reported the initial survey of open ocean pollution by PFCs in 2003. Our studies have shown that part per quadrillion (ppq) level analysis of PFCs is necessary to obtain reliable information of open ocean pollution. We have developed reliable analytical and sampling method for ultra-trace level analysis of PFCs that is applicable to global survey of open ocean pollution. Analysis of PFCs in open ocean waters is challenging because of the need for ppq level analysis and no earlier studies have reported such a sensitive method. There were two approaches to enable trace level analysis of PFCs, namely, to decrease the blank and to solve co-elution problem. We have tested low blank solid phase extraction method and improvements in the analytical procedures and instrumentation, the blank/background levels of target perfluorinated acids were reduced significantly. Field blanks containing 800 mL of HPLC-grade water taken in a polypropylene bottle were transported to sampling locations. Two hundred microliter of sodium thiosulfate solution has been added to the field blanks. Although the concentrations of target fluorochemicals in field blanks were similar to those in procedural blanks in most cases, any sample sets that were found to have notable

  17. Microplastics Baseline Surveys at the Water Surface and in Sediments of the North-East Atlantic

    Directory of Open Access Journals (Sweden)

    Thomas Maes

    2017-05-01

    Full Text Available Microplastic contamination was determined in sediments of the Southern North Sea and floating at the sea surface of North West Europe. Floating concentrations ranged between 0 and 1.5 microplastic/m3, whereas microplastic concentrations in sediments ranged between 0 and 3,146 particles/kg dry weight sediment. In sediments, mainly fibers and spheres were found, whereas at the sea surface fragments were dominant. At the sea surface, concentrations of microplastics are lower and more variable than in sediments, meaning that larger sample sizes and water volumes are required to find detectable concentrations. We have calculated the widths of the confidence intervals (CI for different sample sizes, to give a first indication of the necessary sample size for a microplastic survey at the water surface. Higher concentrations of floating microplastics were found near estuaries. In sediments, estuaries and areas with a high organic carbon content were likely hotspots. Standardization of monitoring methods within marine regions is recommended to compare and assess microplastics pollution over time.

  18. Larval dispersion of the estuarine crab Neohelice granulata in coastal marine waters of the Southwest Atlantic

    Science.gov (United States)

    Bas, Claudia; Luppi, Tomás; Spivak, Eduardo; Schejter, Laura

    2009-08-01

    The estuarine brachyuran crab Neohelice granulata export their larvae from the parental intertidal population of the Mar Chiquita coastal lagoon, and probably other populations, to marine waters. The degree of larval dispersion or self-recruitment of populations is unknown. We evaluated the presence of all larval stages of N. granulata in coastal waters of Argentina between 37.9° and 35.8° S, at two different spatial scales: a broad scale of tens to hundreds of kilometers from the Río de la Plata estuary in the north, to Mar Chiquita lagoon in the south, and a small scale of hundreds of meters to some kilometers around the mouth of Mar Chiquita, during spring and summer. Additionally, we registered the larval composition and density at San Clemente creek population, in Samborombon Bay (Río de la Plata estuary), every 3 h along a 30-hour period. Evidence indicates that larval release of N. granulata is temporally synchronized with nocturnal ebb tides and all development from Zoea I to Zoea IV occur in areas close to the parental population, even with very different oceanographic characteristics. A possible mechanism based on salinity selection and wind-driven transport is proposed for such behavior, and some considerations related to the connectivity of present populations are made.

  19. Surface signature of Mediterranean water eddies in the Northeastern Atlantic: effect of the upper ocean stratification

    Directory of Open Access Journals (Sweden)

    I. Bashmachnikov

    2012-11-01

    Full Text Available Meddies, intra-thermocline eddies of Mediterranean water, can often be detected at the sea surface as positive sea-level anomalies. Here we study the surface signature of several meddies tracked with RAFOS floats and AVISO altimetry.

    While pushing its way through the water column, a meddy raises isopycnals above. As a consequence of potential vorticity conservation, negative relative vorticity is generated in the upper layer. During the initial period of meddy acceleration after meddy formation or after a stagnation stage, a cyclonic signal is also generated at the sea-surface, but mostly the anticyclonic surface signal follows the meddy.

    Based on geostrophy and potential vorticity balance, we present theoretical estimates of the intensity of the surface signature. It appears to be proportional to the meddy core radius and to the Coriolis parameter, and inversely proportional to the core depth and buoyancy frequency. This indicates that surface signature of a meddy may be strongly reduced by the upper ocean stratification. Using climatic distribution of the stratification intensity, we claim that the southernmost limit for detection in altimetry of small meddies (with radii on the order of 10–15 km should lie in the subtropics (35–45° N, while large meddies (with radii of 25–30 km could be detected as far south as the northern tropics (25–35° N. Those results agree with observations.

  20. Chemical and isotopic characteristics of the warm and cold waters of the Luigiane Spa near Guardia Piemontese (Calabria, Italy) in a complex faulted geological framework

    International Nuclear Information System (INIS)

    Vespasiano, Giovanni; Apollaro, Carmine; Muto, Francesco; Dotsika, Elissavet; De Rosa, Rosanna; Marini, Luigi

    2014-01-01

    Highlights: • Geo-structural and hydrogeological patterns: thermal waters discharge in a tectonic window. • Use of S isotopes to discriminate different evaporite sources, considering effects of BSR. • Use of the local approach instead of the regional approach to investigate the thermal site. • Use of geothermometric functions specifically calibrated for the thermal waters of interest. • Synthesis of geo-structural, hydrogeological and geochemical results in a conceptual model. - Abstract: Waters discharging at the Luigiane Spa come from two different hydrogeological circuits, which are chiefly hosted in the carbonate rocks and Upper Triassic evaporites of two distinct geological units, known as Verbicaro Unit and Cetraro Unit. The first unit contains a cold and relatively shallow aquifer behaving as a sort of piston-flow circuit with high flow rate, whereas the second unit encloses a warm and comparatively deep aquifer acting as a sort of well-mixed reservoir, where the circulation is slower and the rate is lower. Meteoric waters infiltrating along the Coastal Chain at similar elevations (615–670 m asl on average, in spite of considerable uncertainties) recharge both aquifers and, in the first case, acquire heat from rocks through conductive transfer as a consequence of deepening along a fault system and/or crossing between different systems, as suggested by local structural geology. In particular, the warm deeper reservoir has a temperature of ∼60 °C, as indicated by the chalcedony solubility and the Ca–Mg and SO 4 –F geothermometers, which were specifically calibrated for the peculiar water–rock-interaction (WRI) processes originating the Na–Cl–SO 4 high-salinity warm waters that discharge at the Luigiane Spa. The warm deeper reservoir is probably located at depths close to 1.4 km, assuming a geothermal gradient of 33 °C km −1 . The water leaving the deep reservoir discharges at the surface at 40.9 ± 3.3 °C after a relatively fast

  1. Interhemispheric teleconnections: Late Pliocene change in Mediterranean outflow water linked to changes in Indonesian Through-Flow and Atlantic Meridional Overturning Circulation, a review and update

    Science.gov (United States)

    Sarnthein, Michael; Grunert, Patrick; Khélifi, Nabil; Frank, Martin; Nürnberg, Dirk

    2018-03-01

    The ultimate, possibly geodynamic control and potential impact of changes in circulation activity and salt discharge of Mediterranean outflow waters (MOW) on Atlantic meridional overturning circulation have formed long-standing objectives in paleoceanography. Late Pliocene changes in the distal advection of MOW were reconstructed on orbital timescales for northeast Atlantic DSDP/ODP sites 548 and 982 off Brittany and on Rockall Plateau, supplemented by a proximal record from Site U1389 west off Gibraltar, and compared to Western Mediterranean surface and deep-water records of Alboran Sea Site 978. From 3.43 to 3.3 Ma, MOW temperatures and salinities form a prominent rise by 2-4 °C and 3 psu, induced by a preceding and coeval rise in sea surface and deep-water salinity and increased summer aridity in the Mediterranean Sea. We speculate that these changes triggered an increased MOW flow and were ultimately induced by a persistent 2.5 °C cooling of Indonesian Through-Flow waters. The temperature drop resulted from the northward drift of Australia that crossed a threshold value near 3.6-3.3 Ma and led to a large-scale cooling of the eastern subtropical Indian Ocean and in turn, to a reduction of African monsoon rains. Vice versa, we show that the distinct rise in Mediterranean salt export after 3.4 Ma induced a unique long-term rise in the formation of Upper North Atlantic Deep Water, that followed with a phase lag of 100 ky. In summary, we present evidence for an interhemispheric teleconnection of processes in the Indonesian Gateways, the Mediterranean and Labrador Seas, jointly affecting Pliocene climate.

  2. Heat flux estimate of warm water flow in a low-temperature diffuse flow site, southern East Pacific Rise 17°25‧ S

    Science.gov (United States)

    Goto, Shusaku; Kinoshita, Masataka; Mitsuzawa, Kyohiko

    2003-09-01

    A low-temperature diffuse flow site associated with abundant vent fauna was found by submersible observations on the southern East Pacific Rise at 17°25‧ S in 1997. This site was characterized by thin sediment covered pillow and sheet lavas with collapsed pits up to ˜15 m in diameter. There were three warm water vents (temperature: 6.5 to 10.5 °C) within the site above which the vented fluids rise as plumes. To estimate heat flux of the warm water vents, a temperature logger array was deployed and the vertical temperature distribution in the water column up to 38 m above the seafloor was monitored. A stationary deep seafloor observatory system was also deployed to monitor hydrothermal activity in this site. The temperature logger array measured temperature anomalies, while the plumes from the vents passed through the array. Because the temperature anomalies were measured in only specific current directions, we identified one of the vents as the source. Heat flux from the vent was estimated by applying a plume model in crossflow in a density-stratified environment. The average heat flux from September 13 to October 18, 1997 was 39 MW. This heat flux is as same order as those of high-temperature black smokers, indicating that a large volume flux was discharged from the vent (1.9 m3/s). Previous observations found many similar warm water flow vents along the spreading axis between 17°20‧ S 30‧ S. The total heat flux was estimated to be at least a few hundred mega-watts. This venting style would contribute to form effluent hydrothermal plumes extended above the spreading axis.

  3. Evaluating the role of fronts in habitat overlaps between cold and warm water species in the western North Pacific: A proof of concept

    Science.gov (United States)

    Mugo, Robinson M.; Saitoh, Sei-Ichi; Takahashi, Fumihiro; Nihira, Akira; Kuroyama, Tadaaki

    2014-09-01

    Cold- and warm-water species' fishing grounds show a spatial synchrony around fronts in the western North Pacific (WNP). However, it is not yet clear whether a front (thermal, salinity or chlorophyll) acts as an absolute barrier to fish migration on either side or its structure allows interaction of species with different physiological requirements. Our objective was to assess potential areas of overlap between cold- and warm-water species using probabilities of presence derived from fishery datasets and remotely sensed environment data in the Kuroshio-Oyashio region in the WNP. Fishery data comprised skipjack tuna (Katsuwonus pelamis) fishing locations and proxy presences (derived from fishing night light images) for neon flying squid (Ommastrephes bartrami) and Pacific saury (Cololabis saira). Monthly (August-November) satellite remotely sensed sea-surface temperature, chlorophyll-a and sea-surface height anomaly images were used as environment data. Maximum entropy (MaxEnt) models were used to determine probabilities of presence (PoP) for each set of fishery and environment data for the area 35-45°N and 140-160°E. Maps of both sets of PoPs were compared and areas of overlap identified using a combined probability map. Results indicated that areas of spatial overlap existed among the species habitats, which gradually widened from September to November. The reasons for these overlaps include the presence of strong thermal/ocean-color gradients between cold Oyashio and warm Kuroshio waters, and also the presence of the sub-arctic front. Due to the high abundance of food along frontal zones, the species use the fronts as foraging grounds while confining within physiologically tolerable waters on either side of the front. The interaction zone around the front points to areas that might be accessible to both species for foraging, which suggests intense prey-predator interaction zones.

  4. Water pollution and distribution of the black fly (Diptera: Simuliidae in the Atlantic Forest, Brazil

    Directory of Open Access Journals (Sweden)

    Tatiana N Docile

    2015-09-01

    Full Text Available Abstract:Black flies have medical importance because some species are vectors of the Onchocerciasis and Mansonelosis, nevertheless, their ecology and potential use as bioindicators is still poorly studied in the Neotropical Region. In Brazil, bioindicators use is strongly focused in a multimetrical ecological index approach; this way, we investigated the black fly spatial distribution, in relation to abiotic factors correlated to water quality, to provide baseline information for their utilization as standalone indicators of lotic systems integrity. We have tested the hypothesis that environmental changes related to urbanization, lead to decreased abundance and loss in the number of species of the black fly fauna. The sampling was conducted in 10 urban and 10 preserved streams during the dry season (August-September of 2012, in the mountainous region of Teresópolis, State of Rio de Janeiro, Brazil. The streams were characterized for their environmental integrity conditions and physico-chemical properties of water. In each stream, five different rapid points were sampled in a section of 50 meters, 10 meters apart from each other. The black flies were sampled with a kick-net sampler on rocky substrates. The material was separated and the larvae were sorted in morphotypes, and later, the final instar specimens were dissected and identified with the help of taxonomical literature at species level. A total abundance of 488 larvae from nine species were collected, 5 (1.02 % in extremely impacted streams, 470 (96.31 % in intermediate streams and 13 (2.66 % in preserved streams. The visual evaluation (HII differed in rela&tion to the water physico-chemical evaluation, in which more variation in the characterization of the sampling sites was observed. In Canonical Correspondence Analysis Simulium subpallidum, S. inscrustatumand S. pertinaxwere significantly associated with intermediate values of most of the variables, and then to intermediate impacted

  5. Water pollution and distribution of the black fly (Diptera: Simuliidae) in the Atlantic Forest, Brazil.

    Science.gov (United States)

    Docile, Tatiana N; Figueiró, Ronaldo; Gil-Azevedo, Leonardo H; Nessimian, Jorge L

    2015-09-01

    Black flies have medical importance because some species are vectors of the unenocerciasis and Mansonelosis, nevertheless, their ecology and potential use as bioindicators is still poorly studied in the Neotropical Region. In Brazil, bioindicators use is strongly focused in a multimetrical ecological index approach; this way, we investigated the black fly spatial distribution, in relation to abiotic factors correlated to water quality, to provide baseline information for their utilization as standalone indicators of lotic systems integrity. We have tested the hypothesis that environmental changes related to urbanization, lead to decreased abundance and loss in the number of species of the black fly fauna. The sampling was conducted in 10 urban and 10 preserved streams during the dry season (August-September) of 2012, in the mountainous region of Teres6polis, State of Rio de Janeiro, Brazil. The streams were characterized for their environmental integrity conditions and physico-chemical properties of water. In each stream, five different rapid points were sampled in a section of 50 meters, 10 meters apart from each other. The black flies were sampled with a kick-net sampler on rocky substrates. The material was separated and the larvae were sorted in morphotypes, and later, the final instar specimens were dissected and identified with the help of taxonomical literature at species level. A total abundance of 488 larvae from nine species were collected, 5 (1.02 %) in extremely impacted streams, 470 (96.31 %) in intermediate streams and 13 (2.66 %) in preserved streams. The visual evaluation (HII) differed in relation to the water physico-chemical evaluation, in which more variation in the characterization of the sampling sites was observed. In Canonical Correspondence Analysis Simulium subpallidum, S. inscrustatum and S. pertinax were significantly associated with intermediate values of most of the variables, and then to intermediate impacted sites. On the other hand

  6. Global Warming: A Reduced Threat?.

    Science.gov (United States)

    Michaels, Patrick J.; Stooksbury, David E.

    1992-10-01

    One popular and apocalyptic vision of the world influenced by increasing concentrations of infrared-absorbing trace gases is that of ecological disaster brought about by rapidly rising temperatures, sea level, and evaporation rates. This vision developed from a suite of climate models that have since considerably changed in both their dynamics and their estimates of prospective warming. Observed temperatures indicate that much more warming should already have taken place than predicted by earlier models in the Northern Hemisphere, and that night, rather than day, readings in that hemisphere show a relative warming. A high-latitude polar-night warming or a general night warming could be either benign or beneficial. A large number of plant species show both increased growth and greater water-use efficiency under enhanced carbon dioxide.An extensive body of evidence now indicates that anthropo-generated sulfate emissions are mitigating some of the warming, and that increased cloudiness as a result of these emissions will further enhance night, rather than day, warming. The sulfate emissions, though, are not sufficient to explain all of the night warming. However, the sensitivity of climate to anthropogenerated aerosols, and the general lack of previously predicted warming, could drastically alter the debate on global warming in favor of less expensive policies.

  7. Benthic macroinvertebrates as bioindicators of water quality in an Atlantic forest fragment

    Directory of Open Access Journals (Sweden)

    Augusto Oliveira

    2010-12-01

    Full Text Available The objective of this study was to evaluate benthic macroinvertebrate communities as bioindicators of water quality in five streams located in the "Reserva Particular do Patrimônio Natural" (RPPN Mata Samuel de Paula and its surroundings, in the municipality of Nova Lima near the city of Belo Horizonte, Minas Gerais State, southeastern Brazil. This region has been strongly modified by human activities including mining and urbanization. Samples were collected in the field every three months between August 2004 and November 2005, totaling six samplings in the rainy and dry seasons. This assessment identified one area ecologically altered while the other sampling sites were found to be minimally disturbed systems, with well-preserved ecological conditions. However, according to the Biological Monitoring Work Party (BMWP and the Average Score Per Taxon (ASPT indices, all sampling sites had excellent water quality. A total of 14,952 organisms was collected, belonging to 155 taxa (148 Insecta, two Annelida, one Bivalvia, one Decapoda, one Planariidae, one Hydracarina, and one Entognatha. The most abundant benthic groups were Chironomidae (47.9%, Simuliidae (12.3%, Bivalvia (7.5%, Decapoda (6.1%, Oligochaeta (5.2%, Polycentropodidae (3.7%, Hydropsychidae (2.5%, Calamoceratidae (1.8%, Ceratopogonidae (1.7%, and Libellulidae (1.2%. The assessment of the benthic functional feeding groups showed that 34% of the macroinvertebrates were collector-gatherers, 29% predators, 24% collector-filterers, 8% shredders, and 5% scrapers. The RPPN Mata Samuel de Paula comprises diversified freshwater habitats that are of great importance for the conservation of many benthic taxa that are intolerant to organic pollution.

  8. Bull trout distribution and abundance in the waters on and bordering the Warm Springs Indian Reservation: 2001 annual report

    International Nuclear Information System (INIS)

    Brun, Christopher V.; Dodson, Rebekah D.

    2002-01-01

    The range of bull trout (Salvelinus confluentus) in the Deschutes River basin has decreased from historic levels due to many factors including dam construction, habitat degradation, brook trout introduction and eradication efforts. While the bull trout population appears to be stable in the Metolius River-Lake Billy Chinook system they have been largely extirpated from the upper Deschutes River (Buchanan et al. 1997). Little was known about bull trout in the lower Deschutes basin until BPA funded project No.9405400 began during 1998. In this progress report we describe the findings from the fourth year (2001) of the multi-year study aimed at determining the life history, habitat needs and limiting factors of bull trout in the lower Deschutes subbasin. Juvenile bull trout and brook trout (Salvelinus fontinalis) relative abundance was assessed in the Warm Springs River and Shitike Creek by night snorkeling. In the Warm Springs R. juvenile bull trout were slightly more numerous than brook trout, however, both were found in low densities. Relative densities of both species were the lowest observed since surveys began in 1999. Relative densities of juvenile bull trout and brook trout increased in Shitike Cr. Juvenile bull trout vastly out numbered brook trout in Shitike Cr. The utility of using index reaches to monitor trends in juvenile bull trout and brook trout relative abundance was assessed in the Warm Springs R. for the third year. Mean relative densities of juvenile bull trout within the index reaches was slightly higher than what was observed in the 2.4 km control reach. However, the mean relative density of brook trout in the 2.4 km control reach was slightly higher than what was observed in within the index reaches. Habitat use by both juvenile bull trout and brook trout was determined in the Warm Springs R. Juvenile bull trout and brook trout occupied pools more frequently than glides, riffles and rapids. However, pools accounted for only a small percentage

  9. Are Calanus spp. shifting poleward in the North Atlantic? A habitat modelling approach

    KAUST Repository

    Chust, Guillem

    2013-09-16

    In the last decade, the analysis based on Continuous Plankton Recorder survey in the eastern North Atlantic Ocean detected one of the most striking examples of marine poleward migration related to sea warming. The main objective of this study is to verify the poleward shift of zooplankton species (Calanus finmarchicus, C. glacialis, C. helgolandicus, C. hyperboreus) for which distributional changes have been recorded in the North Atlantic Ocean and to assess how much of this shift was triggered by sea warming, using Generalized Additive Models. To this end, the population gravity centre of observed data was compared with that of a series of simulation experiments: (i) a model using only climate factors (i.e. niche-based model) to simulate species habitat suitability, (ii) a model using only temporal and spatial terms to reconstruct the population distribution, and (iii) a model using both factors combined, using a subset of observations as independent dataset for validation. Our findings show that only C. finmarchicus had a consistent poleward shift, triggered by sea warming, estimated in 8.1 km per decade in the North Atlantic (16.5 per decade for the northeast), which is substantially lower than previous works at the assemblage level and restricted to the Northeast Atlantic. On the contrary, C. helgolandicus is expanding in all directions, although its northern distribution limit in the North Sea has shifted northward. Calanus glacialis and C. hyperboreus, which have the geographic centres of populations mainly in the NW Atlantic, showed a slight southward shift, probably responding to cool water penetrating southward in the Labrador Current. Our approach, supported by high model accuracy, shows its power in detecting species latitudinal shifts and identifying its causes, since the trend of occurrence observed data is influenced by the sampling frequency, which has progressively concentrated to lower latitudes with time. © 2013 © 2013 International Council for

  10. Recent warming of lake Kivu.

    Science.gov (United States)

    Katsev, Sergei; Aaberg, Arthur A; Crowe, Sean A; Hecky, Robert E

    2014-01-01

    Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  11. Recent warming of lake Kivu.

    Directory of Open Access Journals (Sweden)

    Sergei Katsev

    Full Text Available Lake Kivu in East Africa has gained notoriety for its prodigious amounts of dissolved methane and dangers of limnic eruption. Being meromictic, it is also expected to accumulate heat due to rising regional air temperatures. To investigate the warming trend and distinguish between atmospheric and geothermal heating sources, we compiled historical temperature data, performed measurements with logging instruments, and simulated heat propagation. We also performed isotopic analyses of water from the lake's main basin and isolated Kabuno Bay. The results reveal that the lake surface is warming at the rate of 0.12°C per decade, which matches the warming rates in other East African lakes. Temperatures increase throughout the entire water column. Though warming is strongest near the surface, warming rates in the deep waters cannot be accounted for solely by propagation of atmospheric heat at presently assumed rates of vertical mixing. Unless the transport rates are significantly higher than presently believed, this indicates significant contributions from subterranean heat sources. Temperature time series in the deep monimolimnion suggest evidence of convection. The progressive deepening of the depth of temperature minimum in the water column is expected to accelerate the warming in deeper waters. The warming trend, however, is unlikely to strongly affect the physical stability of the lake, which depends primarily on salinity gradient.

  12. Predation on larval Atlantic herring (Clupea harengus) in inshore waters of the Baltic Sea

    Science.gov (United States)

    Kotterba, Paul; Moll, Dorothee; von Nordheim, Lena; Peck, Myron A.; Oesterwind, Daniel; Polte, Patrick

    2017-11-01

    In fishery science, early life-stage survival and development are regarded as major factors driving the population dynamics of marine fishes. During the last century, the main research focus has been on the spatio-temporal match of larval fish and appropriate food (bottom-up processes). However, these field studies are often criticised for their limited capability to disentangle their results from mortality caused by predation since these top-down mechanisms are rarely studied. We examined the predation on herring (Clupea harengus) larvae in a Baltic inshore lagoon by investigating the spatio-temporal overlap of larval herring and their potential predators such as the dominant threespine stickleback (Gasterosteus aculeatus) in distinct habitats (sublittoral and littoral areas) using a set of different gears and sampling techniques. Despite significant spatial and temporal predator-prey overlap, stomach analyses suggested that very few larvae were consumed by sticklebacks, even if projected to the entire study area and season. Other well-known predators of clupeid larvae such as gelatinous plankton occur later in the year after young herring have migrated out of the system. The observed predation on herring larvae was much less than expected and appears being a minor factor in determining herring reproduction success in our study area, particularly if compared to other causes of mortality such as egg predation. Providing a relatively good shelter from predation might be a key element making transitional waters valuable nursery grounds for the offspring of migrating marine fish species.

  13. Spraguea lophii (Microsporidia) parasitizing blackbellied angler (Lophius budegassa) and angler (L. piscatorius) in European Atlantic waters

    Science.gov (United States)

    Landa, Jorge; Cañás, Lucía

    2017-12-01

    Blackbellied angler (Lophius budegassa) and angler (L. piscatorius) are two important commercial species in the Bay of Biscay and the European fisheries infected by the microsporidian parasite Spraguea lophii. Samplings of both anglerfish were performed from a nine year time-series (2006-2014) from commercial fleet and bottom research surveys operating in southern Bay of Biscay and Galician waters (ICES Div. VIIIc and IXa2), Celtic Sea (Div. VIIh), south-western Ireland (Div. VIIj and VIIk), western Ireland and Porcupine Bank (Div. VIIb and VIIc). Length and sex of fish and presence or absence of the parasite were recorded. The prevalence by Spraguea was used to analyse the infection level. The role of each variable (fish length, fish sex, geographical area and year) and the interactions among them on the Spraguea prevalence were analyzed by using a binomial GLM. Area and fish length had a more relevant effect on the infestation of both anglerfish, while the impact of the year and fish sex was less evident. The Spraguea prevalence by area ranged between 11% and 52% in L. budegassa and between 39% and 66% in L. piscatorius. This is the first study in which the prevalence of this parasite in L. budegassa is analyzed in several areas and inter-annually compared. A non-linear relationship with a sharp increment of the prevalence with fish length was obtained in both anglerfish. The results were compared with those from the scarce previous studies and discussed.

  14. Production and degradation of fluorescent dissolved organic matter in surface waters of the eastern north Atlantic ocean

    Science.gov (United States)

    Lønborg, Christian; Yokokawa, Taichi; Herndl, Gerhard J.; Antón Álvarez-Salgado, Xosé

    2015-02-01

    The distribution and fate of coloured dissolved organic matter (CDOM) in the epipelagic Eastern North Atlantic was investigated during a cruise in the summer 2009 by combining field observations and culture experiments. Dissolved organic carbon (DOC) and nitrogen (DON), the absorption spectra of CDOM and the fluorescence intensity of proteins (Ex/Em 280/320 nm; F(280/320)) and marine humic-like substances (F(320/410)) were measured in the upper 200 m. DOC and DON showed higher concentrations in the top 20 m than below, and DOC increased southwards, while DON decreased. F(280/320) and F(320/410) showed maxima near the deep chlorophyll maximum (at about 50 m), suggesting that these fluorophores were linked to phytoplankton production and the metabolism of the associated microbial community. The coloured and fluorescent fractions of DOM showed low levels south of the Azores Front, at about 35 °N, likely due to the accumulated photobleaching of the waters transported eastwards by the Azores current into the study area (at 20°W). Twelve culture experiments were also conducted with surface water (5 m) to assess the impact of microbial degradation processes on the bulk, coloured and fluorescent fractions of DOM. After 72 h of incubation in the darkness, 14±9% (average±SD) of the initial DON was consumed at an average rate of 0.24±0.14 μmol l-1 d-1 and the protein-like fluorescence decayed by 29±9% at a net rate of 0.06±0.03 QSU d-1. These rates were significantly lower south of the Azores front, suggesting that DOM in this region was of a more recalcitrant nature. Conversely, the marine humic-like fluorescence increased at a net rate of 0.013±0.003 QSU d-1. The close linear relationship of DON uptake with F(280/320) consumption (R2= 0.91, p <0.0001, n=12) and F(320/410) production (R2= 0.52, p <0.008, n=12) that we found during these incubation experiments suggest that the protein-like fluorescence can be used as a proxy for the dynamics of the labile DON pool

  15. Swim speed, behavior, and movement of North Atlantic right whales (Eubalaena glacialis in coastal waters of northeastern Florida, USA.

    Directory of Open Access Journals (Sweden)

    James H W Hain

    Full Text Available In a portion of the coastal waters of northeastern Florida, North Atlantic right whales (Eubalaena glacialis occur close to shore from December through March. These waters are included within the designated critical habitat for right whales. Data on swim speed, behavior, and direction of movement--with photo-identification of individual whales--were gathered by a volunteer sighting network working alongside experienced scientists and supplemented by aerial observations. In seven years (2001-2007, 109 tracking periods or "follows" were conducted on right whales during 600 hours of observation from shore-based observers. The whales were categorized as mother-calf pairs, singles and non-mother-calf pairs, and groups of 3 or more individuals. Sample size and amount of information obtained was largest for mother-calf pairs. Swim speeds varied within and across observation periods, individuals, and categories. One category, singles and non mother-calf pairs, was significantly different from the other two--and had the largest variability and the fastest swim speeds. Median swim speed for all categories was 1.3 km/h (0.7 kn, with examples that suggest swim speeds differ between within-habitat movement and migration-mode travel. Within-habitat right whales often travel back-and-forth in a north-south, along-coast, direction, which may cause an individual to pass by a given point on several occasions, potentially increasing anthropogenic risk exposure (e.g., vessel collision, fishing gear entanglement, harassment. At times, mothers and calves engaged in lengthy stationary periods (up to 7.5 h that included rest, nursing, and play. These mother-calf interactions have implications for communication, learning, and survival. Overall, these behaviors are relevant to population status, distribution, calving success, correlation to environmental parameters, survey efficacy, and human-impacts mitigation. These observations contribute important parameters to

  16. The impact of horizontal heterogeneities, cloud fraction, and cloud dynamics on warm cloud effective radii and liquid water path from CERES-like Aqua MODIS retrievals

    OpenAIRE

    D. Painemal; P. Minnis; S. Sun-Mack

    2013-01-01

    The impact of horizontal heterogeneities, liquid water path (LWP from AMSR-E), and cloud fraction (CF) on MODIS cloud effective radius (re), retrieved from the 2.1 μm (re2.1) and 3.8 μm (re3.8) channels, is investigated for warm clouds over the southeast Pacific. Values of re retrieved using the CERES Edition 4 algorithms are averaged at the CERES footprint resolution (~ 20 km), while heterogeneities (Hσ) are calculated as the ratio between the standard deviation and mean...

  17. The impact of horizontal heterogeneities, cloud fraction, and liquid water path on warm cloud effective radii from CERES-like Aqua MODIS retrievals

    OpenAIRE

    Painemal, D.; Minnis, P.; Sun-Mack, S.

    2013-01-01

    The impact of horizontal heterogeneities, liquid water path (LWP from AMSR-E), and cloud fraction (CF) on MODIS cloud effective radius (re), retrieved from the 2.1 μm (re2.1) and 3.8 μm (re3.8) channels, is investigated for warm clouds over the southeast Pacific. Values of re retrieved using the CERES algorithms are averaged at the CERES footprint resolution (∼20 km), while heterogeneities (Hσ) are calculated as the ratio between the standard deviation and mean 0.64 μm reflectance. ...

  18. 75 FR 44938 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery

    Science.gov (United States)

    2010-07-30

    ... Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery AGENCY: National... moratorium on fishing for Atlantic coastal sharks in the State waters of New Jersey. NMFS canceled the... Fisheries Commission's (Commission) Interstate Fishery Management Plan for Atlantic Coastal Sharks (Coastal...

  19. Global warming

    International Nuclear Information System (INIS)

    Houghton, John

    2005-01-01

    'Global warming' is a phrase that refers to the effect on the climate of human activities, in particular the burning of fossil fuels (coal, oil and gas) and large-scale deforestation, which cause emissions to the atmosphere of large amounts of 'greenhouse gases', of which the most important is carbon dioxide. Such gases absorb infrared radiation emitted by the Earth's surface and act as blankets over the surface keeping it warmer than it would otherwise be. Associated with this warming are changes of climate. The basic science of the 'greenhouse effect' that leads to the warming is well understood. More detailed understanding relies on numerical models of the climate that integrate the basic dynamical and physical equations describing the complete climate system. Many of the likely characteristics of the resulting changes in climate (such as more frequent heat waves, increases in rainfall, increase in frequency and intensity of many extreme climate events) can be identified. Substantial uncertainties remain in knowledge of some of the feedbacks within the climate system (that affect the overall magnitude of change) and in much of the detail of likely regional change. Because of its negative impacts on human communities (including for instance substantial sea-level rise) and on ecosystems, global warming is the most important environmental problem the world faces. Adaptation to the inevitable impacts and mitigation to reduce their magnitude are both necessary. International action is being taken by the world's scientific and political communities. Because of the need for urgent action, the greatest challenge is to move rapidly to much increased energy efficiency and to non-fossil-fuel energy sources

  20. Climatic impacts of fresh water hosing under Last Glacial Maximum conditions: a multi-model study

    Directory of Open Access Journals (Sweden)

    M. Kageyama

    2013-04-01

    Full Text Available Fresh water hosing simulations, in which a fresh water flux is imposed in the North Atlantic to force fluctuations of the Atlantic Meridional Overturning Circulation, have been routinely performed, first to study the climatic signature of different states of this circulation, then, under present or future conditions, to investigate the potential impact of a partial melting of the Greenland ice sheet. The most compelling examples of climatic changes potentially related to AMOC abrupt variations, however, are found in high resolution palaeo-records from around the globe for the last glacial period. To study those more specifically, more and more fresh water hosing experiments have been performed under glacial conditions in the recent years. Here we compare an ensemble constituted by 11 such simulations run with 6 different climate models. All simulations follow a slightly different design, but are sufficiently close in their design to be compared. They all study the impact of a fresh water hosing imposed in the extra-tropical North Atlantic. Common features in the model responses to hosing are the cooling over the North Atlantic, extending along the sub-tropical gyre in the tropical North Atlantic, the southward shift of the Atlantic ITCZ and the weakening of the African and Indian monsoons. On the other hand, the expression of the bipolar see-saw, i.e., warming in the Southern Hemisphere, differs from model to model, with some restricting it to the South Atlantic and specific regions of the southern ocean while others simulate a widespread southern ocean warming. The relationships between the features common to most models, i.e., climate changes over the north and tropical Atlantic, African and Asian monsoon regions, are further quantified. These suggest a tight correlation between the temperature and precipitation changes over the extra-tropical North Atlantic, but different pathways for the teleconnections between the AMOC/North Atlantic region

  1. Enhanced deep ocean ventilation and oxygenation with global warming

    Science.gov (United States)

    Froelicher, T. L.; Jaccard, S.; Dunne, J. P.; Paynter, D.; Gruber, N.

    2014-12-01

    Twenty-first century coupled climate model simulations, observations from the recent past, and theoretical arguments suggest a consistent trend towards warmer ocean temperatures and fresher polar surface oceans in response to increased radiative forcing resulting in increased upper ocean stratification and reduced ventilation and oxygenation of the deep ocean. Paleo-proxy records of the warming at the end of the last ice age, however, suggests a different outcome, namely a better ventilated and oxygenated deep ocean with global warming. Here we use a four thousand year global warming simulation from a comprehensive Earth System Model (GFDL ESM2M) to show that this conundrum is a consequence of different rates of warming and that the deep ocean is actually better ventilated and oxygenated in a future warmer equilibrated climate consistent with paleo-proxy records. The enhanced deep ocean ventilation in the Southern Ocean occurs in spite of increased positive surface buoyancy fluxes and a constancy of the Southern Hemisphere westerly winds - circumstances that would otherwise be expected to lead to a reduction in deep ocean ventilation. This ventilation recovery occurs through a global scale interaction of the Atlantic Meridional Overturning Circulation undergoing a multi-centennial recovery after an initial century of transient decrease and transports salinity-rich waters inform the subtropical surface ocean to the Southern Ocean interior on multi-century timescales. The subsequent upwelling of salinity-rich waters in the Southern Ocean strips away the freshwater cap that maintains vertical stability and increases open ocean convection and the formation of Antarctic Bottom Waters. As a result, the global ocean oxygen content and the nutrient supply from the deep ocean to the surface are higher in a warmer ocean. The implications for past and future changes in ocean heat and carbon storage will be discussed.

  2. Is This the Only Hope for Reversing Global Warming? Transitioning Each Country's All-Purpose Energy to 100% Electricity Powered by Wind, Water, and Solar

    Science.gov (United States)

    Jacobson, M. Z.

    2016-12-01

    Global warming, air pollution, and energy insecurity are three of the most significant problems facing the world today. Can these problems be solved with existing technologies implemented on a large scale or do we need to wait for a miracle technology? This talk discusses the development of technical and economic plans to convert the energy infrastructure of each of 139 countries of the world to those powered by 100% wind, water, and sunlight (WWS) for all purposes using existing technology along with efficiency measures. All purposes includes electricity, transportation, heating/cooling, industry, and agriculture/forestry/fishing. The roadmaps propose using existing WWS generator technologies along with existing electrical transportation, heating/cooling, and industrial devices and appliances, plus existing electricity storage technologies, (CSP with storage, pumped hydroelectric storage, and existing hydroelectric power) and existing heat/cold storage technologies (water, ice, and rocks) for the transitions. They envision 80% conversion to WWS by 2030 and 100% by 2050. WWS not only replaces business-as-usual (BAU) power, but also reduces 2050 BAU demand due to the higher work to energy ratio of WWS electricity over combustion, the elimination of energy for mining, transporting, and processing fuels, and improvements in end-use efficiency beyond BAU. The study examines job creation versus loss, land use requirements, air pollution mortality and morbidity cost differences, and global warming cost differences due to the conversion in each country. Results suggest that implementing these roadmaps will stabilize energy prices because fuel costs are zero; reduce international conflict by creating energy-independent countries; reduce energy poverty; reduce power disruption by decentralizing power; and avoid exploding CO2 levels. Thus, the study concludes that a 100% WWS transition provides at least one solution to global warming Please see http

  3. Distributions and habitat associations of deep-water corals in Norfolk and Baltimore Canyons, Mid-Atlantic Bight, USA

    NARCIS (Netherlands)

    Brooke, S.D.; Watts, M.W.; Heil, A.D.; Rhode, M.; Mienis, F.; Duineveld, G.C.A.; Davies, A.J.; Ross, S.W.

    2017-01-01

    A multi-disciplinary study of two major submarine canyons, Baltimore Canyon and Norfolk Canyon, off the US mid-Atlantic coast focused on the ecology and biology of canyon habitats, particularly those supporting deep-sea corals. Historical data on deep-sea corals from these canyons were sparse with

  4. Mercury in the atmosphere, snow and melt water ponds in the North Atlantic Ocean during Arctic summer.

    Science.gov (United States)

    Aspmo, Katrine; Temme, Christian; Berg, Torunn; Ferrari, Christophe; Gauchard, L Pierre-Alexis; Fain, Xavier; Wibetoe, Grethe

    2006-07-01

    Atmospheric mercury speciation measurements were performed during a 10 week Arctic summer expedition in the North Atlantic Ocean onboard the German research vessel RV Polarstern between June 15 and August 29, 2004. This expedition covered large areas of the North Atlantic and Arctic Oceans between latitudes 54 degrees N and 85 degrees N and longitudes 16 degrees W and 16 degrees E. Gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated with particles (Hg-P) were measured during this study. In addition, total mercury in surface snow and meltwater ponds located on sea ice floes was measured. GEM showed a homogeneous distribution over the open North Atlantic Ocean (median 1.53 +/- 0.12 ng/m3), which is in contrast to the higher concentrations of GEM observed over sea ice (median 1.82 +/- 0.24 ng/m3). It is hypothesized that this results from either (re-) emission of mercury contained in snow and ice surfaces that was previously deposited during atmospheric mercury depletion events (AMDE) in the spring or evasion from the ocean due to increased reduction potential at high latitudes during Arctic summer. Measured concentrations of total mercury in surface snow and meltwater ponds were low (all samples RGM and Hg-P without a significant diurnal variability. These results indicate that the production and deposition of these reactive mercury species do not significantly contribute to the atmospheric mercury cycle in the North Atlantic Ocean during the Arctic summer.

  5. Production and degradation of fluorescent dissolved organic matter in surface waters of the eastern north Atlantic ocean

    NARCIS (Netherlands)

    Lønborg, C.; Yokokawa, T.; Herndl, G.J.; Alvarez-Salgado, X.A.

    2015-01-01

    The distribution and fate of coloured dissolved organic matter (CDOM) in the epipelagic Eastern North Atlantic was investigated during a cruise in the summer 2009 by combining field observations and culture experiments. Dissolved organic carbon (DOC) and nitrogen (DON), the absorption spectra of

  6. Recent trends in the abundance of plaice Pleuronectes platessa and cod Gadus morhua in shallow coastal waters of the Northeastern Atlantic continental shelf – a review

    DEFF Research Database (Denmark)

    Dutz, Jörg; Støttrup, Josianne Gatt; Stenberg, Claus

    2016-01-01

    of the southern distribution boundary in the Bay of Biscay and deepening of stocks in the North Sea. In contrast, no trend in shallow water abundance of plaice similar to a decline in deep-water stocks during the 1970s and their slow recovery during the 2000s is apparent in the Skagerrak/Kattegat. Although......Shallow, near-shore water habitats on the continental shelf of the Northeast Atlantic have been productive fishing areas in the past. Here, we review the present knowledge about (i) recent trends in the abundance of plaice and cod in these habitats and (ii) hypotheses regarding the factors...... responsible for any trends. At present, only a few studies exist on the trends of abundance of plaice or cod, namely from the Bay of Biscay, the North Sea and the Skagerrak/Kattegat. They suggest a declining abundance in coastal, shallow areas and – at least for plaice – a latitudinal gradient with an erosion...

  7. Shallow-water Mysidacea from the Lesser Antilles and other Caribbean regions

    NARCIS (Netherlands)

    Brattegard, Torleiv

    1975-01-01

    This report is the seventh in a series of papers dealing with Mysidacea (Crustacea) from shallow water in the tropical and warm-temperate areas of the western Atlantic (BRATTEGARD 1969, 1970a, 1970b, 1973, 1974a, 1974b). Five of these are dealing with material collected by the author in southern

  8. Post-Glacial Development of Western North Atlantic - Labrador Sea Oceanographic Circulation

    DEFF Research Database (Denmark)

    Sheldon, Christina

    2015-01-01

    The subpolar North Atlantic Ocean – Labrador Sea region is an important site for both oceanographic and atmospheric circulation. The convergence of ocean currents causes downwelling of cold, saline water in the subpolar gyre, helping to drive the world-wide thermohaline circulation system. The main......, the subpolar gyre weakened, which carried less Gulf Stream-derived water to the western North Atlantic Ocean via the West Greenland Current and the Slopewater Current, south of Newfoundland. Changes in the subpolar gyre circulation had developed to be analogous to the modern climate by approximately 2 cal kyr...... surface currents involved in the gyre are the south-flowing, cold and relatively fresh Labrador Current and the north-flowing, warm and relatively saline Gulf Stream. The oceanic front between these two major currents moves north and south, dependent on the relative strengths of the currents, impacting...

  9. A warm thermal enclave in the late Pleistocene of the south-eastern United States.

    Science.gov (United States)

    Russell, Dale A; Rich, Fredrick J; Schneider, Vincent; Lynch-Stieglitz, Jean

    2009-05-01

    Physical and biological evidence supports the probable existence of an enclave of relatively warm climate located between the Southern Appalachian Mountains and the Atlantic Ocean in the United States during the Last Glacial Maximum. The region supported a mosaic of forest and prairie habitats inhabited by a "Floridian" ice-age biota. Plant and vertebrate remains suggest an ecological gradient towards Cape Hatteras (35 degreesN) wherein forests tended to replace prairies, and browsing proboscideans tended to replace grazing proboscideans. Beyond 35 degreesN, warm waters of the Gulf Stream were deflected towards the central Atlantic, and a cold-facies biota replaced "Floridian" biota on the Atlantic coastal plain. Because of niche diversity and relatively benign climate, biodiversity may have been greater in the south-eastern thermal enclave than in other unglaciated areas of North America. However, the impact of terminal Pleistocene megafaunal extinctions may also have been shorter and more severe in the enclave than further north. A comparison with biotic changes that occurred in North America approximately 55 million years (ma) ago at the Paleocene-Eocene Thermal Maximum suggests that similar processes of change took place under both ice-house and greenhouse climates.

  10. Global warming

    CERN Document Server

    Hulme, M

    1998-01-01

    Global warming-like deforestation, the ozone hole and the loss of species- has become one of the late 20the century icons of global environmental damage. The threat, is not the reality, of such a global climate change has motivated governments. businesses and environmental organisations, to take serious action ot try and achieve serious control of the future climate. This culminated last December in Kyoto in the agreement for legally-binding climate protocol. In this series of three lectures I will provide a perspective on the phenomenon of global warming that accepts the scientific basis for our concern, but one that also recognises the dynamic interaction between climate and society that has always exited The future will be no different. The challenge of global warning is not to pretend it is not happening (as with some pressure groups), nor to pretend it threatens global civilisation (as with other pressure groups), and it is not even a challenge to try and stop it from happening-we are too far down the ro...

  11. Acute effects of a single warm-water bath on serum adiponectin and leptin levels in healthy men: A pilot study

    Science.gov (United States)

    Shimodozono, Megumi; Matsumoto, Shuji; Ninomiya, Koji; Miyata, Ryuji; Ogata, Atsuko; Etoh, Seiji; Watanabe, Satoshi; Kawahira, Kazumi

    2012-09-01

    To preliminarily assess the acute effects of a single warm -water bath (WWB) on serum adipokine activity, we measured serum adiponectin, leptin and other metabolic profiles before, immediately after and 30 minutes after WWB in seven healthy male volunteers (mean age, 39.7 ± 6.0 years; mean body mass index, 21.6 ± 1.8 kg/m2). The subjects were immersed in tap water at 41°C for 10 minutes. Two weeks later, the same subjects underwent a single WWB with a bath additive that included inorganic salts and carbon dioxide (WWB with ISCO2) by the same protocol as for the first WWB. Leptin levels significantly increased immediately after WWB with tap water and ISCO2 (both P hemoglobin and hematocrit significantly increased immediately after WWB with tap water or ISCO2 (all P < 0.05), but they all returned to the baseline levels 30 minutes after bathing under both conditions. The sublingual temperature rose significantly after 10 minutes of WWB with tap water (0.96 ± 0.16°C relative to baseline, P < 0.01) and after the same duration of WWB with ISCO2 (1.24 ± 0.34°C relative to baseline, P < 0.01). These findings suggest that a single WWB at 41°C for 10 minutes may modulate leptin and adiponectin profiles in healthy men.

  12. Role of the GH-IGF-1 system in Atlantic salmon and rainbow trout postsmolts at elevated water temperature.

    Science.gov (United States)

    Hevrøy, Ernst M; Tipsmark, Christian K; Remø, Sofie C; Hansen, Tom; Fukuda, Miki; Torgersen, Thomas; Vikeså, Vibeke; Olsvik, Pål A; Waagbø, Rune; Shimizu, Munetaka

    2015-10-01

    A comparative experiment with Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) postsmolts was conducted over 35 days to provide insight into how growth, respiration, energy metabolism and the growth hormone (GH) and insulin-like growth factor 1 (IGF-1) system are regulated at elevated sea temperatures. Rainbow trout grew better than Atlantic salmon, and did not show reduced growth at 19 °C. Rainbow trout kept at 19 °C had increased blood hemoglobin concentration compared to rainbow trout kept at 13 °C, while salmon did not show the same hemoglobin response due to increased temperature. Both species showed reduced length growth and decreased muscle glycogen stores at 19 °C. Circulating IGF-1 concentration was higher in rainbow trout than in Atlantic salmon, but was not affected by temperature in either species. Plasma IGF-binding protein 1b (IGFBP-1b) concentration was reduced in Atlantic salmon reared at 19 °C after 15 days but increased in rainbow trout at 19 °C after 35 days. The igfbp1b mRNA level in liver showed a positive correlation to plasma concentrations of glucose and IGFBP-1b, suggesting involvement of this binding protein in carbohydrate metabolism at 19 °C. At this temperature muscle igfbp1a mRNA was down-regulated in both species. The muscle expression of this binding protein correlated negatively with muscle igf1 and length growth. The plasma IGFBP-1b concentration and igfbp1b and igfbp1a expression suggests reduced muscle igf1 signaling at elevated temperature leading to glucose allostasis, and that time course is species specific due to higher thermal tolerance in rainbow trout. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. North Atlantic Coast Comprehensive Study Phase I: Statistical Analysis of Historical Extreme Water Levels with Sea Level Change

    Science.gov (United States)

    2014-09-01

    14-7 ii Abstract The U.S. North Atlantic coast is subject to coastal flooding as a result of both severe extratropical storms (e.g., Nor’easters...Products and Services, excluding any kind of high-resolution hydrodynamic modeling. Tropical and extratropical storms were treated as a single...joint probability analysis and high-fidelity modeling of tropical and extratropical storms

  14. Mechanism for the recent ocean warming events on the Scotian Shelf of eastern Canada

    Science.gov (United States)

    Brickman, D.; Hebert, D.; Wang, Z.

    2018-03-01

    In 2012, 2014, and 2015 anomalous warm events were observed in the subsurface waters in the Scotian Shelf region of eastern Canada. Monthly output from a high resolution numerical ocean model simulation of the North Atlantic ocean for the period 1990-2015 is used to investigate this phenomenon. It is found that the model shows skill in simulating the anomaly fields derived from various sources of data, and the observed warming trend over the last decade. From analysis of the model run it is found that the anomalies originate from the interaction between the Gulf Stream and the Labrador Current at the tail of the Grand Banks (south of Newfoundland). This interaction results in the creation of anomalous warm/salty (or cold/fresh) eddies that travel east-to-west along the shelfbreak. These anomalies penetrate into the Gulf of St. Lawrence, onto the Scotian Shelf, and into the Gulf of Maine via deep channels along the shelfbreak. The observed warming trend can be attributed to an increase in the frequency of creation of warm anomalies during the last decade. Strong anomalous events are commonly observed in the data and model, and thus should be considered as part of the natural variability of the coupled atmosphere-ocean system.

  15. Ca. Branchiomonas cysticola, Ca. Piscichlamydia salmonis and Salmon Gill Pox Virus transmit horizontally in Atlantic salmon held in fresh water.

    Science.gov (United States)

    Wiik-Nielsen, J; Gjessing, M; Solheim, H T; Litlabø, A; Gjevre, A-G; Kristoffersen, A B; Powell, M D; Colquhoun, D J

    2017-10-01

    Elucidation of the role of infectious agents putatively involved in gill disease is commonly hampered by the lack of culture systems for these organisms. In this study, a farmed population of Atlantic salmon pre-smolts, displaying proliferative gill disease with associated Candidatus Branchiomonas cysticola, Ca. Piscichlamydia salmonis and Atlantic salmon gill pox virus (SGPV) infections, was identified. A subpopulation of the diseased fish was used as a source of waterborne infection towards a population of naïve Atlantic salmon pre-smolts. Ca. B. cysticola infection became established in exposed naïve fish at high prevalence within the first month of exposure and the bacterial load increased over the study period. Ca. P. salmonis and SGPV infections were identified only at low prevalence in exposed fish during the trial. Although clinically healthy, at termination of the trial the exposed, naïve fish displayed histologically visible pathological changes typified by epithelial hyperplasia and subepithelial inflammation with associated bacterial inclusions, confirmed by fluorescent in situ hybridization to contain Ca. B. cysticola. The results strongly suggest that Ca. B. cysticola infections transmit directly from fish to fish and that the bacterium is directly associated with the pathological changes observed in the exposed, previously naïve fish. © 2017 John Wiley & Sons Ltd.

  16. Deep-water scleractinian corals (Cnidaria: Anthozoa) from 2010-2011 INDEMARES expeditions to the Galicia Bank (Spain, northeast Atlantic).

    Science.gov (United States)

    Altuna, Alvaro

    2017-11-23

    During surveys in the Galicia Bank (northeastern Atlantic) in the years 2010-2011 (INDEMARES project), 25 species of scleractinian corals corals were collected in a depth interval of 744-1764 m. Most interesting species are described and depicted. Additionally, species list and remarks are given for the 23 species dredged in the bank during the 1987 SEAMOUNT 1 expedition at 675-1125 m depth.From a literature review and new records from Galicia Bank given herein, 31 species of scleractinian corals are known from this seamount in a depth interval of 614-1764 m depth. Six are colonial and 25 solitary, with 17 occurring on hard bottoms and 14 on soft bottoms. Desmophyllum dianthus, Lophelia pertusa and Madrepora oculata are the most widely distributed species in both number of stations and depth range of specimens collected alive. Some species were recorded outside their previously known bathymetric ranges in the northeastern Atlantic. Javania pseudoalabastra is first documented for the Iberian Peninsula and Spanish faunas. Thrypticotrochus sp. is first collected from the Atlantic Ocean.

  17. Effect of Global Warming and Increased Freshwater Flux on Northern Hemispheric Cooling

    Science.gov (United States)

    Girihagama, L. N.; Nof, D.

    2016-02-01

    We wish to answer the, fairly complicated, question of whether global warming and an increased freshwater flux can cause Northern Hemispheric warming or cooling. Starting from the assumption that the ocean is the primary source of variability in the Northern hemispheric ocean-atmosphere coupled system, we employed a simple non-linear one-dimensional coupled ocean-atmosphere model. The simplicity of the model allows us to analytically predict the evolution of many dynamical variables of interest such as, the strength of the Atlantic Meridional overturning circulation (AMOC), temperatures of the ocean and atmosphere, mass transports, salinity, and ocean-atmosphere heat fluxes. The model results show that a reduced AMOC transport due to an increased freshwater flux causes cooling in both the atmosphere and ocean in the North Atlantic (NA) deep-water formation region. Cooling in both the ocean and atmosphere can cause reduction of the ocean-atmosphere temperature difference, which in turn reduces heat fluxes in both the ocean and atmosphere. For present day climate parameters, the calculated critical freshwater flux needed to arrest AMOC is 0.08 Sv. For a constant atmospheric zonal flow, there is minimal reduction in the AMOC strength, as well as minimal warming of the ocean and atmosphere. This model provides a conceptual framework for a dynamically sound response of the ocean and atmosphere to AMOC variability as a function of increased freshwater flux. The results are qualitatively consistent with numerous realistic coupled numerical models of varying complexity.

  18. Final Scientific/Technical Report: Characterizing the Response of the Cascadia Margin Gas Hydrate Reservoir to Bottom Water Warming Along the Upper Continental Slope

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Evan A. [Univ. of Washington, Seattle, WA (United States); Johnson, H. Paul [Univ. of Washington, Seattle, WA (United States); Salmi, Marie [Univ. of Washington, Seattle, WA (United States); Whorley, Theresa [Univ. of Washington, Seattle, WA (United States)

    2017-11-10

    The objective of this project is to understand the response of the WA margin gas hydrate system to contemporary warming of bottom water along the upper continental slope. Through pre-cruise analysis and modeling of archive and recent geophysical and oceanographic data, we (1) inventoried bottom simulating reflectors along the WA margin and defined the upper limit of gas hydrate stability, (2) refined margin-wide estimates of heat flow and geothermal gradients, (3) characterized decadal scale temporal variations of bottom water temperatures at the upper continental slope of the Washington margin, and (4) used numerical simulations to provide quantitative estimates of how the shallow boundary of methane hydrate stability responds to modern environmental change. These pre-cruise results provided the context for a systematic geophysical and geochemical survey of methane seepage along the upper continental slope from 48° to 46°N during a 10-day field program on the R/V Thompson from October 10-19, 2014. This systematic inventory of methane emissions along this climate-sensitive margin corridor and comprehensive sediment and water column sampling program provided data and samples for Phase 3 of this project that focused on determining fluid and methane sources (deep-source vs. shallow; microbial, thermogenic, gas hydrate dissociation) within the sediment, and how they relate to contemporary intermediate water warming. During the 2014 research expedition, we sampled nine seep sites between ~470 and 520 m water depth, within the zone of predicted methane hydrate retreat over the past 40 years. We imaged 22 bubble plumes with heights commonly rising to ~300 meters below sea level with one reaching near the sea surface. We collected 22 gravity cores and 20 CTD/hydrocasts from the 9 seeps and at background locations (no acoustic evidence of seepage) within the depth interval of predicted downslope retreat of the methane hydrate stability zone. Approximately 300 pore water

  19. Inventory, distribution, and origin of aliphatic and polyaromatic hydrocarbons in sea water, the surface microlayer, and the aerosols in the tropical Eastern Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Marty, J C; Saliot, A; Tissier, M J

    1978-03-20

    Hydrocarbons have been analyzed in several samples from ''Midlante'' cruise, Cape Verde islands-Canary islands, in the Eastern tropical Atlantic: subsurface water, sea surface microlayer collected by a metallic screen and aerosols collected by filtration of large air volumes at about 12 m. above the sea surface. Detailed analysis of aliphatic and polyaromatic hydrocarbons has been made by computerized gas chromatography/mass spectrometry. This study of the air/sea interface indicates a discontinuity in hydrocarbon composition between the underlying water and the microlayer and a similarity between the surface microlayer and the aerosols. The origin of the collected aerosols is essentially marine with a minor terrestrial contribution. The hydrocarbon pattern shows that, superimposed on the typical marine components, a contribution from smokes of natural and industrial origin and/or from pollution associated with crude oil sea slicks is present.

  20. Functional responses of North Atlantic fish eggs to increasing temperature

    DEFF Research Database (Denmark)

    Tsoukali, Stavroula; Visser, Andre; MacKenzie, Brian

    2016-01-01

    -days and survival of fish eggs from 32 populations of 17 species in the North Atlantic to different temperatures in order to determine potential consequences of global warming for these species. The response of development time exhibited a similar decreasing trend with respect to temperature across species....... There was an overall decrease, across species, in an index of thermal requirement (cumulative degree-days) for egg development with increasing temperature. Within an empirically derived optimal thermal range for egg survival, the thermal requirement was more variable in species adapted to cold waters compared...... to species adapted to warmer waters. Moreover, the sensitivity of survival of eggs from different species to increases in temperature differed, reflecting a pattern of sensitivity along a stenotherm-eurytherm gradient of vulnerability to temperature among species. The results quantify physiological effects...

  1. Coastal Fog in Atlantic Canada: Characterization and Projection in a Changing Climate

    Science.gov (United States)

    Duplessis, P.; Hartery, S.; Macdonald, A. M.; Wheeler, M.; Miller, J.; Bhatia, S.; Chang, R. Y. W.

    2016-12-01

    Marine and coastal fog in Atlantic Canada is usually advective and favored by the meeting of the warm Gulf Stream and cold Labrador Current. As moist warm air moves over cold water, it cools down and becomes supersaturated. The interactions between microphysical, dynamical and radiative processes can also be a determining element in the formation and persistence of fog, which makes fog forecasting a highly challenging task. Current parameterizations within models suffer notably from unresolved microphysical problems such as neglecting droplet concentration, which leads to errors in droplet density predictions of up to 50%. In the scope of improving our understanding of fog and its characteristics, our research group conducted a field study on the coast of Nova Scotia in Eastern Canada during the fog season of 2016. Meteorological variables, droplet and aerosol size distributions, chemical speciation and fog water composition were measured. Results from this study will be presented, along with projections in a changing climate.

  2. A consistent structure of phytoplankton communities across the warm-cold regions of the water mass on a meridional transect in the East/Japan Sea

    Science.gov (United States)

    Kwak, Jung Hyun; Han, Eunah; Lee, Sang Heon; Park, Hyun Je; Kim, Kyung-Ryul; Kang, Chang-Keun

    2017-09-01

    Three cruises were undertaken along a meridional transect in the East/Japan Sea (EJS) in spring (May 2007), summer (July 2009), and fall (October 2012) to determine the geographic variations in phytoplankton biomass and community composition. This study revealed a gradient of surface temperature and a fluctuation of hydrographic conditions along the transect. Although a subpolar front (SPF) formed between the warm- and cold-water masses (37-40°N), no significant differences in phytoplankton biomass and community composition were detected between the southern and northern parts of the EJS. These results disprove our initial hypothesis that different water masses may contain differently structured phytoplankton communities. In the present study, isothermal layers (≤ 12 °C) fluctuated over a depth of 50 m in both warm- and cold-water masses, depending on the SPF. In contrast, the nitracline (i.e. 2.5 μM nitrate isopleth) depth was recorded within a limited range of 20-40 m in spring, 30-50 m in summer, and 40-60 m in fall. The chlorophyll a concentrations at the subsurface chlorophyll maxima (SCM) were significantly higher in spring and summer (356 ± 233 and 270 ± 182 ng L-1, respectively) than in fall (117 ± 89 ng L-1). The relative contributions of individual phytoplankton groups to the depth-integrated chlorophyll a concentration conformed to the composition of the phytoplankton community in the SCM layer, showing a dominance of diatoms (58 ± 19% in spring, 48 ± 11% in summer, and 30 ± 20% in fall). Canonical correspondence analysis revealed that the geographic structures of phytoplankton communities were strongly associated with the vertical structures of water temperature and nutrient concentration in the water column rather than with horizontal gradients of hydrographic conditions. Finally, our findings suggest that water column stability and light-nutrient availability in the euphotic zone play a key role in determining geographical consistency of

  3. Investigating the influence of nitrate nitrogen on post-smolt Atlantic salmon Salmo salar reproductive physiology in water recirculation aquaculture systems

    Science.gov (United States)

    Good, Christopher; Davidson, John; Iwanowicz, Luke R.; Meyer, Michael T.; Dietze, Julie E.; Kolpin, Dana W.; Marancik, David; Birkett, Jill; Williams, Christina; Summerfelt, Steven T.

    2017-01-01

    A major issue affecting land-based, closed containment Atlantic salmon Salmo salar growout production in water recirculation aquaculture systems (RAS) is precocious male maturation, which can negatively impact factors such as feed conversion, fillet yield, and product quality. Along with other water quality parameters, elevated nitrate nitrogen (NO3-N) has been shown to influence the reproductive development and endogenous sex steroid production in a number of aquatic animal species, including Atlantic salmon. We sought to determine whether elevated NO3-N in RAS can influence early maturation in post-smolt Atlantic salmon in an 8-month trial in replicated freshwater RAS. Post-smolt Atlantic salmon (102 ± 1 g) were stocked into six RAS, with three RAS randomly selected for dosing with high NO3-N (99 ± 1 mg/L) and three RAS set for low NO3-N (10 ± 0 mg/L). At 2-, 4-, 6-, and 8-months post-stocking, 5 fish were randomly sampled from each RAS, gonadosomatic index(GSI) data were collected, and plasma was sampled for 11-ketotestosterone(11-KT) quantification. At 4- and 8-months post-stocking, samples of culture tank and spring water (used as “makeup” or replacement water) were collected and tested for a suite of 42 hormonally active compounds using liquid chromatography/mass spectrometry, as well as for estrogenicity using the bio