Spatial variability in total and organic mercury levels in Antarctic krill Euphausia superba across the Scotia Sea
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Total and organic mercury concentrations were determined for males, females and juveniles of Euphausia superba collected at three discrete locations in the Scotia Sea (the South Orkney Islands, South Georgia and the Antarctic Polar Front) to assess spatial mercury variability in Antarctic krill. There was clear geographic differentiation in mercury concentrations, with specimens from the South Orkneys having total mercury concentrations 5 to 7 times higher than Antarctic krill from South Georgia and the Antarctic Polar Front. Mercury did not appear to accumulate with life-stage since juveniles had higher concentrations of total mercury (0.071 μg g−1 from South Orkney Islands; 0.015 μg g−1 from South Georgia) than adults (0.054 μg g−1 in females and 0.048 μg g−1 in males from South Orkney Islands; 0.006 μg g−1 in females and 0.007 μg g−1 in males from South Georgia). Results suggest that females use egg laying as a mechanism to excrete mercury, with eggs having higher concentrations than the corresponding somatic tissue. Organic mercury makes up a minor percentage of total mercury (15–37%) with the percentage being greater in adults than in juveniles. When compared to euphausiids from other parts of the world, the concentration of mercury in Antarctic krill is within the same range, or higher, highlighting the global distribution of this contaminant. Given the high potential for biomagnification of mercury through food webs, concentrations in Antarctic krill may have deleterious effects on long-lived Antarctic krill predators.
Seco , J , Xavier , J C , Coelho , J P , Pereira , B , Tarling , G , Pardal , M A , Bustamante , P , Stowasser , G , Brierley , A S & Pereira , M E 2019 , ' Spatial variability in total and organic mercury levels in Antarctic krill Euphausia superba across the Scotia Sea ' , Environmental Pollution , vol. 247 , pp. 332-339 . https://doi.org/10.1016/j.envpol.2019.01.031
Copyright © 2019 Published by Elsevier Ltd. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1016/j.envpol.2019.01.031
DescriptionWe acknowledge the Portuguese Foundation for Science and Technology through a PhD grant to José Seco (SRFH/PD/BD/113487). Acknowledgments are due also to the Integrated Program of SR&TD ‘Smart Valorization of Endogenous Marine Biological Resources Under a Changing Climate’ (reference Centro-01-0145-FEDER-000018), co-funded by Centro 2020 program, Portugal 2020, European Union, through the European Regional Development Fund, for personal funding to J.P.Coelho. The IUF is acknowledged for its support to P. Bustamante as a Senior Member. This research was also within José Xavier strategic program of MARE (MARE - UID/MAR/04292/2013).
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