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Wintering in the western subarctic pacific increases mercury contamination of Red-legged Kittiwakes

November 6, 2019

Marine methylmercury concentrations vary geographically and with depth, exposing organisms to different mercury levels in unique habitats. Red-legged kittiwakes (Rissa brevirostris), a specialist predator, forage on fish and invertebrates from the mesopelagic zone, a part of the ocean with elevated methylmercury concentrations. We used kittiwakes as bioindicators of MeHg concentrations in remote mesopelagic systems by examining how wintering distribution and habitat affected kittiwakes’ mercury exposure. In 2011-2017, we sampled winter-grown feathers on St. George Island, Alaska, from birds equipped with geolocation loggers. We measured total mercury (THg) and nitrogen stable in nape and head feathers grown during winter, respectively. THg concentration of kittiwake nape feathers averaged 4.61 ± 0.97 µg/g dry weight. Hierarchical cluster analysis was used to classify winter habitats with remotely sensed environmental variables along each bird’s track. Five habitat clusters were identified. Birds that spent more time in the Western Subarctic Gyre and those that wintered further south had elevated THg concentrations. In contrast to THg, trophic level varied annually but did not show strong spatial patterns. Our results documented spatial variability in THg exposure based on the oceanic wintering locations of red-legged kittiwakes and highlight their use as a bioindicator of MeHg across ocean basins.

Publication Year 2020
Title Wintering in the western subarctic pacific increases mercury contamination of Red-legged Kittiwakes
DOI 10.1021/acs.est.9b03421
Authors Abram S Fleishman, Rachael Orben, Nobuo Kokubun, Alexis Will, Rosana Paredes, Joshua T. Ackerman, Akinori Takahashi, Alexander Kitaysky, Scott A. Shaffer
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science & Technology
Index ID 70208106
Record Source USGS Publications Warehouse
USGS Organization Western Ecological Research Center