The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Susie M Grant - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in seabed temperatures in the southern ocean implications for Benthic Ecology and biogeography
Journal of Geophysical Research, 2009Co-Authors: Andrew Clarke, Huw J Griffiths, David K A Barnes, Michael P Meredith, Susie M GrantAbstract:The Antarctic seabed has traditionally been regarded as cold and thermally stable, with little spatial or seasonal variation in temperature. Here we demonstrate marked spatial variations in continental shelf seabed temperature around Antarctica, with the western Antarctic Peninsula shelf significantly warmer than shelves around continental Antarctica as a result of flooding of the shelf by Circumpolar Deep Water from the Antarctic Circumpolar Current. The coldest shelf seabed temperatures are in the Weddell Sea, Ross Sea, and Prydz Bay as a consequence of seasonal convection associated with strong air-sea heat fluxes and sea-ice formation. These waters constitute the dense precursors of Antarctic Bottom Water, and can descend down the adjacent slope to inject cold water into the Southern Ocean deep sea. Deep sea seabed temperatures are coldest in the Weddell Sea and are progressively warmer to the east. There is a distinct latitudinal gradient in the difference between seabed temperatures on the shelf and in the deep sea, with the deep sea warmer by up to similar to 2 K at high latitudes and colder by similar to 2 K around sub-Antarctic islands. These differences have important consequences for Benthic Ecology and biogeography, understanding the evolutionary history of the Antarctic marine biota, and the impact of regional climate change.
Nicole R Wade - One of the best experts on this subject based on the ideXlab platform.
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Benthic Ecology of the northeastern chukchi sea part i environmental characteristics and macrofaunal community structure 2008 2010
Continental Shelf Research, 2013Co-Authors: Arny L Blanchard, Carrie L Parris, Ann Knowlton, Nicole R WadeAbstract:Spatial variations of processes driving macrofaunal distributions can arise from interactions among topographic features and oceanographic patterns, and are not understood at small scales in the northeastern Chukchi Sea. Benthic macrofauna and environmental characteristics were measured to determine factors driving macrofaunal distributions as part of a multidisciplinary environmental program in the northeastern Chukchi Sea from 2008 to 2010. Macrofauna were sampled in three study areas, named Klondike, Burger, and Statoil, with a van Veen grab at up to 82 stations each year, as well as an area where marine mammals were seen feeding. The macrofaunal assemblages in all study areas were similar in species-composition with deposit-feeding polychaetes (53% of density and of 26% biomass) and bivalves (15% of density and 52% of biomass) collectively the most prominent groups. Maldane sarsi dominated the polychaetes in terms of both density and biomass, while bivalves were numerically dominated by Ennucula tenuis, but their biomass was dominated by larger species such as Macoma calcarea and Astarte borealis. Exceptions occurred in the marine mammal feeding area that was dominated by amphipods (71% of density and 30% biomass). Average densities were higher in Burger than in Klondike or Statoil, while biomass values were similar between Burger and Statoil, and higher in these two study areas than in Klondike. Overall, the distributions, biomass and density of Benthic macrofauna reflect the high volume of production reaching the seafloor in the shallow waters of the Chukchi Sea. Variations in community structure among study areas were correlated with water depth and bottom-water temperature. Short-term temporal differences in community structure covaried with interannual oceanographic variations that may have altered food availability, macrofaunal survival, or larval recruitment. Topographic control over circulation appears to be a primary driver in structuring Benthic communities within the present study region, as well as throughout the Chukchi Sea.
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Benthic Ecology of the northeastern chukchi sea part ii spatial variation of megafaunal community structure 2009 2010
Continental Shelf Research, 2013Co-Authors: Arny L Blanchard, Carrie L Parris, Ann Knowlton, Nicole R WadeAbstract:Abstract Sources for spatial variability of Benthic megafaunal communities in the northeastern Chukchi Sea are poorly documented and may include altered water circulation patterns, as noted for macrofauna. Spatial variability of megafauna was investigated by sampling with a plumb-staff beam trawl in three petroleum leases, the Klondike, Burger, and Statoil study areas, as part of a multi-disciplinary research program in the northeastern Chukchi Sea ecosystem. Trawling occurred during two sampling periods from 2009 and one in 2010 with a total of 81 trawls from 38 stations. A total of 99 discrete taxonomic categories were identified in 2009 and 2010 which were expanded to 239 taxa in the laboratory. Biomass in the three study areas ranged from ∼15,500 to ∼96,000 g 1000 m −2 and numerical density ranged from ∼8500 to ∼134,000 individuals 1000 m −2 . Although the megaBenthic species-assemblages in all three study areas were similar in composition, average biomass values were higher in Burger (ranging from ∼54,000 to ∼96,000 g 1000 m −2 ) where altered water circulation occurs, than in Klondike (ranging from ∼15,500 to ∼31,000 g 1000 m −2 ) or Statoil (∼15,000 g 1000 m −2 ). The brittle star Ophiura sarsi was the numerically dominant megafauna (70% of total biomass) followed by the snow crab Chionoecetes opilio (7% total biomass), as noted in prior investigations in the region. Biomass and density of Benthic megafauna in this region reflected the high quantities of seasonal production reaching the benthos in the shallow waters of the Chukchi Sea. Differences in Benthic communities among study areas were associated with variations in bottom-water temperature and latitude, and to a lesser extent, water depth and percent mud. We believe these associations arise from effects of topography on northward-flowing water, that create regions of slower currents, and consequently, higher organic deposition.
Andrew Clarke - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in seabed temperatures in the southern ocean implications for Benthic Ecology and biogeography
Journal of Geophysical Research, 2009Co-Authors: Andrew Clarke, Huw J Griffiths, David K A Barnes, Michael P Meredith, Susie M GrantAbstract:The Antarctic seabed has traditionally been regarded as cold and thermally stable, with little spatial or seasonal variation in temperature. Here we demonstrate marked spatial variations in continental shelf seabed temperature around Antarctica, with the western Antarctic Peninsula shelf significantly warmer than shelves around continental Antarctica as a result of flooding of the shelf by Circumpolar Deep Water from the Antarctic Circumpolar Current. The coldest shelf seabed temperatures are in the Weddell Sea, Ross Sea, and Prydz Bay as a consequence of seasonal convection associated with strong air-sea heat fluxes and sea-ice formation. These waters constitute the dense precursors of Antarctic Bottom Water, and can descend down the adjacent slope to inject cold water into the Southern Ocean deep sea. Deep sea seabed temperatures are coldest in the Weddell Sea and are progressively warmer to the east. There is a distinct latitudinal gradient in the difference between seabed temperatures on the shelf and in the deep sea, with the deep sea warmer by up to similar to 2 K at high latitudes and colder by similar to 2 K around sub-Antarctic islands. These differences have important consequences for Benthic Ecology and biogeography, understanding the evolutionary history of the Antarctic marine biota, and the impact of regional climate change.
Arny L Blanchard - One of the best experts on this subject based on the ideXlab platform.
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Benthic Ecology of the northeastern chukchi sea part i environmental characteristics and macrofaunal community structure 2008 2010
Continental Shelf Research, 2013Co-Authors: Arny L Blanchard, Carrie L Parris, Ann Knowlton, Nicole R WadeAbstract:Spatial variations of processes driving macrofaunal distributions can arise from interactions among topographic features and oceanographic patterns, and are not understood at small scales in the northeastern Chukchi Sea. Benthic macrofauna and environmental characteristics were measured to determine factors driving macrofaunal distributions as part of a multidisciplinary environmental program in the northeastern Chukchi Sea from 2008 to 2010. Macrofauna were sampled in three study areas, named Klondike, Burger, and Statoil, with a van Veen grab at up to 82 stations each year, as well as an area where marine mammals were seen feeding. The macrofaunal assemblages in all study areas were similar in species-composition with deposit-feeding polychaetes (53% of density and of 26% biomass) and bivalves (15% of density and 52% of biomass) collectively the most prominent groups. Maldane sarsi dominated the polychaetes in terms of both density and biomass, while bivalves were numerically dominated by Ennucula tenuis, but their biomass was dominated by larger species such as Macoma calcarea and Astarte borealis. Exceptions occurred in the marine mammal feeding area that was dominated by amphipods (71% of density and 30% biomass). Average densities were higher in Burger than in Klondike or Statoil, while biomass values were similar between Burger and Statoil, and higher in these two study areas than in Klondike. Overall, the distributions, biomass and density of Benthic macrofauna reflect the high volume of production reaching the seafloor in the shallow waters of the Chukchi Sea. Variations in community structure among study areas were correlated with water depth and bottom-water temperature. Short-term temporal differences in community structure covaried with interannual oceanographic variations that may have altered food availability, macrofaunal survival, or larval recruitment. Topographic control over circulation appears to be a primary driver in structuring Benthic communities within the present study region, as well as throughout the Chukchi Sea.
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Benthic Ecology of the northeastern chukchi sea part ii spatial variation of megafaunal community structure 2009 2010
Continental Shelf Research, 2013Co-Authors: Arny L Blanchard, Carrie L Parris, Ann Knowlton, Nicole R WadeAbstract:Abstract Sources for spatial variability of Benthic megafaunal communities in the northeastern Chukchi Sea are poorly documented and may include altered water circulation patterns, as noted for macrofauna. Spatial variability of megafauna was investigated by sampling with a plumb-staff beam trawl in three petroleum leases, the Klondike, Burger, and Statoil study areas, as part of a multi-disciplinary research program in the northeastern Chukchi Sea ecosystem. Trawling occurred during two sampling periods from 2009 and one in 2010 with a total of 81 trawls from 38 stations. A total of 99 discrete taxonomic categories were identified in 2009 and 2010 which were expanded to 239 taxa in the laboratory. Biomass in the three study areas ranged from ∼15,500 to ∼96,000 g 1000 m −2 and numerical density ranged from ∼8500 to ∼134,000 individuals 1000 m −2 . Although the megaBenthic species-assemblages in all three study areas were similar in composition, average biomass values were higher in Burger (ranging from ∼54,000 to ∼96,000 g 1000 m −2 ) where altered water circulation occurs, than in Klondike (ranging from ∼15,500 to ∼31,000 g 1000 m −2 ) or Statoil (∼15,000 g 1000 m −2 ). The brittle star Ophiura sarsi was the numerically dominant megafauna (70% of total biomass) followed by the snow crab Chionoecetes opilio (7% total biomass), as noted in prior investigations in the region. Biomass and density of Benthic megafauna in this region reflected the high quantities of seasonal production reaching the benthos in the shallow waters of the Chukchi Sea. Differences in Benthic communities among study areas were associated with variations in bottom-water temperature and latitude, and to a lesser extent, water depth and percent mud. We believe these associations arise from effects of topography on northward-flowing water, that create regions of slower currents, and consequently, higher organic deposition.
David K A Barnes - One of the best experts on this subject based on the ideXlab platform.
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spatial variation in seabed temperatures in the southern ocean implications for Benthic Ecology and biogeography
Journal of Geophysical Research, 2009Co-Authors: Andrew Clarke, Huw J Griffiths, David K A Barnes, Michael P Meredith, Susie M GrantAbstract:The Antarctic seabed has traditionally been regarded as cold and thermally stable, with little spatial or seasonal variation in temperature. Here we demonstrate marked spatial variations in continental shelf seabed temperature around Antarctica, with the western Antarctic Peninsula shelf significantly warmer than shelves around continental Antarctica as a result of flooding of the shelf by Circumpolar Deep Water from the Antarctic Circumpolar Current. The coldest shelf seabed temperatures are in the Weddell Sea, Ross Sea, and Prydz Bay as a consequence of seasonal convection associated with strong air-sea heat fluxes and sea-ice formation. These waters constitute the dense precursors of Antarctic Bottom Water, and can descend down the adjacent slope to inject cold water into the Southern Ocean deep sea. Deep sea seabed temperatures are coldest in the Weddell Sea and are progressively warmer to the east. There is a distinct latitudinal gradient in the difference between seabed temperatures on the shelf and in the deep sea, with the deep sea warmer by up to similar to 2 K at high latitudes and colder by similar to 2 K around sub-Antarctic islands. These differences have important consequences for Benthic Ecology and biogeography, understanding the evolutionary history of the Antarctic marine biota, and the impact of regional climate change.
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Benthic Ecology of pockmarks in the inner oslofjord norway
Marine Ecology Progress Series, 2009Co-Authors: Karen E Webb, David K A Barnes, John S GrayAbstract:Despite pockmarks being one of the most widespread small-scale topographic features of the seabed, almost nothing is known of their influence on fauna. Here we present the first ecolog- ical study of fjordic pockmarks, focusing on the contrast between macrofauna inside and outside of these craters. We report an analysis of macrofauna from 27 pockmarks of the Inner Oslofjord, Nor- way. Five replicate grab samples were collected from each of 3 pockmarks at 3 sites plus a further control (non-pockmark) sample at each site. A single grab sample was collected from an additional 3 pockmarks at 6 sites and 6 control locations. We compared macrofaunal assemblages inside and outside of pockmarks and found important but subtle differences to those on non-pockmarked sub- strata. The fauna of pockmarks were typical of a disturbed fjord environment with a dominance of small opportunistic taxa, such as pioneer bivalves and polychaetes. The position of sites in the fjord gradient drove the most obvious faunal differences, but contrary to expectations, we could find no influence of pockmarks on the composition of the fauna at any taxonomic level. This makes them very unusual amongst marine topographic features, which usually have considerable influence on the nature of Benthic communities. However, we found that pockmarks do significantly alter the abun- dances of key species and, as such, we suggest that the presence of pockmarks in the Oslofjord has a considerable cumulative influence on densities and populations of Benthic organisms.
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Local population disappearance follows (20 yr after) cycle collapse in a pivotal ecological species
Marine Ecology Progress Series, 2002Co-Authors: David K A Barnes, Emma Verling, Anne C. Crook, Ian C. Davidson, Maria O'mahoneyAbstract:Populations of the echinoid Paracentrotus lividus have undergone spectacular population fluctuations over the last 40 yr at Lough Hyne, SW Ireland, Censuses in 2000 and 2001, reported here, show no individuals present in the South Basin of Lough Hyne, for what is believed to be, the first time since observations began in the late 1920s. As with many echinoids, R lividus was considered to have a pivotal role in Benthic Ecology through control of algae by grazing, The discontinuation of P. lividus in South Basin of Lough Hyne is significant for 3 reasons. First, the database was 1 of the longest running censuses of a discrete echinoid population anywhere, Second, some corresponding environmental and population size structure data had been recorded over several decades. Third, P lividus was very important in structuring the shallow Benthic community of the oldest marine reserve in Europe.