11 research outputs found

    Time trends and trophic transfer of polybrominated diphenylethers (PBDEs) in Antarctic biota

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    Polybrominated diphenyl ethers (PBDEs) are “emerged” contaminants that were produced and used as flame retardants in numerous consumer and industrial applications for decades until banned. They remain ubiquitously present in the environment today. Here, a unique set of \u3e200 biotic samples from the Antarctic was analyzed for PBDEs, including phytoplankton, krill, fish, and fur seal milk, spanning several sampling seasons over 14 years. PBDE-47 and -99 were the dominant congeners determined in all samples, constituting \u3e60% of total PBDEs. A temporal trend was observed for ∑7PBDE concentrations in fur seal milk, where concentrations significantly increased (R2 = 0.57, p \u3c 0.05) over time (2000–2014). Results for krill and phytoplankton also suggested increasing PBDE concentrations over time. Trends of PBDEs in fur seal milk of individual seals sampled 1 or more years apart showed no clear temporal trends. Overall, there was no indication of PBDEs decreasing in Antarctic biota yet, whereas numerous studies have reported decreasing trends in the northern hemisphere. Similar PBDE concentrations in perinatal versus nonperinatal milk implied the importance of local PBDE sources for bioaccumulation. These results indicate the need for continued assessment of contaminant trends, such as PBDEs, and their replacements, in Antarctica

    Trophic position and foraging ecology of Ross, Weddell, and crabeater seals revealed by compound-specific isotope analysis

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    Ross seals Ommatophoca rossii are one of the least studied marine mammals, with little known about their foraging ecology. Research to date using bulk stable isotope analysis suggests that Ross seals have a trophic position intermediate between that of Weddell Leptonychotes weddellii and crabeater Lobodon carcinophaga seals. However, consumer bulk stable isotope values not only reflect trophic dynamics, but also variations in baseline isotope values, which can be substantial. We used compound-specific isotope analysis of amino acids (CSI-AA) to separate isotopic effects of a shifting baseline versus trophic structure on the foraging ecology of these ecologically important Antarctic pinnipeds. We found that Ross seals forage in an open ocean food web, while crabeater and Weddell seals forage within similar food webs closer to shore. However, isotopic evidence suggests that crabeater seals are likely following sea ice, while Weddell seals target productive areas of the continental shelf of West Antarctica. Our CSI-AA data indicate that Ross seals have a high trophic position equivalent to that of Weddell seals, contrary to prior conclusions from nitrogen isotope results on bulk tissues. CSI-AA indicates that crabeater seals are at a trophic position lower than that of Ross and Weddell seals, consistent with a krill-dominated diet. Our results redefine the view of the trophic dynamics and foraging ecology of the Ross seal, and also highlight the importance of quantifying baseline isotope variations in foraging studies

    Carbon and Nitrogen Isoscapes in West Antarctica Reflect Oceanographic Transitions

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    Antarctic marine ecosystems are spatially and temporally dynamic. Regional climate change is significantly altering the patterns and magnitudes of this dynamism with cascading impacts on biogeochemistry, productivity, and food web architecture. Isoscapes (or isotopic maps) provide a valuable analytical framework to characterize ecosystem processes and address questions about trophic dynamics, animal movement, and elemental cycling. Applications of stable isotope methods to Antarctic ecosystems are currently limited by a paucity of information on geospatial isotope characteristics within the Southern Ocean. In response, we have created the first empirically derived zooplankton isoscapes for West Antarctica based on analysis of bulk nitrogen and carbon isotope values (ÎŽ15N and ÎŽ13C) in 94 zooplankton specimens from the Drake Passage, West Antarctic Peninsula (WAP), and Amundsen and Ross Seas. The zooplankton ÎŽ15N values increased by 3‰ from north of the Polar Front (3.3 ± 0.6‰, mean ± SD) to the Ross Sea (6.2 ± 0.8‰), reflecting a productivity gradient across this region. Abundant open water polynyas in the Amundsen and Ross Seas exhibit strong nitrate drawdown, resulting in more 15N-enriched phytoplankton and zooplankton relative to those from the generally less productive WAP and Drake Passage. Zooplankton ÎŽ13C values decreased by 3‰ from north of the Polar Front (-24.2 ± 0.9‰) to the Ross Sea (-27.5 ± 1.6‰), likely driven by decreasing sea surface temperatures with increasing latitude. Our isoscapes are a valuable first step in establishing isotopic spatial patterns in West Antarctica and are critical for addressing numerous ecosystem questions

    Time Trends of Polybrominated Diphenyl Ethers (PBDEs) in Antarctic Biota

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    Polybrominated diphenyl ethers (PBDEs) are “emerged” contaminants that were produced and used as flame retardants in numerous consumer and industrial applications for decades until banned. They remain ubiquitously present in the environment today. Here, a unique set of >200 biotic samples from the Antarctic was analyzed for PBDEs, including phytoplankton, krill, fish, and fur seal milk, spanning several sampling seasons over 14 years. PBDE-47 and -99 were the dominant congeners determined in all samples, constituting >60% of total PBDEs. A temporal trend was observed for ∑<sub>7</sub>PBDE concentrations in fur seal milk, where concentrations significantly increased (<i>R</i><sup>2</sup> = 0.57, <i>p</i> < 0.05) over time (2000–2014). Results for krill and phytoplankton also suggested increasing PBDE concentrations over time. Trends of PBDEs in fur seal milk of individual seals sampled 1 or more years apart showed no clear temporal trends. Overall, there was no indication of PBDEs decreasing in Antarctic biota yet, whereas numerous studies have reported decreasing trends in the northern hemisphere. Similar PBDE concentrations in perinatal versus nonperinatal milk implied the importance of local PBDE sources for bioaccumulation. These results indicate the need for continued assessment of contaminant trends, such as PBDEs, and their replacements, in Antarctica

    Correction to: An autosomal dominant neurological disorder caused by de novo variants in FAR1 resulting in uncontrolled synthesis of ether lipids (Genetics in Medicine, (2021), 23, 4, (740-750), 10.1038/s41436-020-01027-3)

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    In the original author list, Seth Perlman’s degrees were listed as MD, PhD. Dr Perlman’s degree is MD. The original version has been corrected
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