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

Environmental Science & Technology
By: , and 



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.

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Publication type Article
Publication Subtype Journal Article
Title Wintering in the western subarctic pacific increases mercury contamination of Red-legged Kittiwakes
Series title Environmental Science & Technology
DOI 10.1021/acs.est.9b03421
Volume 53
Issue 22
Year Published 2020
Language English
Publisher ACS
Contributing office(s) Western Ecological Research Center
Description 10 p.
First page 13398
Last page 13407
Country United States
State Alaska
Other Geospatial St. George Island
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