Migratory seabirds are exposed to various pollutants throughout their annual cycle. Among them, mercury (Hg) is of particular concern given its large impact on animal health. Recent studies suggest that winter is a critical period for seabirds when contamination by Hg can be higher than at other times of year. However, individuals within and between species can have different migration strategies and winter distributions that could affect their exposure. Here, we combined multi-year individual tracking data and Hg measurements from 6 Arctic seabird species. We investigated whether inter-annual variations in individual winter contamination with Hg was related to seabird fidelity to a wintering site over years. First, our results show that Hg concentrations above the toxicity threshold (i.e. 5 Μg g-1 dry weight in feathers) were observed in variable proportions according to species (from 2% of northern fulmars to 37% of Brunnich's guillemots). Second, individuals with high fidelity to a wintering ground had more similar Hg concentrations among years compared to individuals with low fidelity, suggesting an effect of their migratory strategy on Hg contamination. Further, we found that the directional change in wintering areas among years influenced seabird Hg contamination, highlighting an additional effect of seabirds' winter distribution. More specifically, individuals migrating to the northwest direction of a previous wintering ground tended to be more contaminated compared to those moving to eastern directions. These results confirm spatial differences in Hg concentration throughout the North Atlantic-Arctic and an east-west gradient increase in Hg concentrations. Verifying this trend will require more large-scale ecotoxicological studies at smaller spatial resolution.
|Number of pages||12|
|Journal||Marine Ecology Progress Series|
|Publication status||Published - Oct 2021|
Bibliographical noteFunding Information:
Acknowledgments. This study is part of several research programs supported by the French Agency for National Research (MAMBA project ANR-16-TERC-0004, ILETOP project ANR-16-CE34-0005, ARCTIC-STRESSORS project ANR-20-CE34-0006), the French Arctic Initiative − CNRS (PARCS project), the Mission pour l’Interdisciplinarité − CNRS (Changements en Sibérie project), the French Polar Institute (IPEV − Pgr 388 ADACLIM) and the European Commission (Marie Curie CIG, Project 631203). This work was supported by a grant (232019) from the Fram Center flagship ‘Climate Change in Fjord and Coast’ to B.M. The IUF (Institut Universitaire de France) is also acknowledged for its support to P.B. as a Senior Member. C.A. was supported by a PhD fellowship from the French Ministry of Higher Education and Research. Thanks to the CPER (Contrat de Projet Etat-Région) and the FEDER (Fonds Européen de Développement Régional) for funding the AMA (Ad vanced Mercury Analyser) and the IRMS (Isotope-Radio Mass Spectrometry) of LIENSs laboratory. We thank the plateforme analytique of the Institut du Littoral, Environnement et Sociétés (LIENSs) and Maud Brault-Favrou for the technical support with the Hg analyses. Fieldwork on Eynhallow was conducted under permits from the British Trust for Ornithology for catching and instrumenting fulmars, and the UK Home Office for feather sampling. We thank Orkney Islands Council for access to this colony. The deployment and retrieval of GLS-loggers and sampling of feathers were conducted as part of the SEATRACK project (www.seapop.no/ en/ seatrack/) in northern Europe (Norwegian and UK colonies), made possible through close cooperation with the SEAPOP program (www.seapop.no, Norwegian Research Council grant #192141) and ARCTOX net work (https://arc-tox. cnrs.fr). We are grateful to Jonathan A. Green and 2 anonymous reviewers for their comments that greatly improved the initial manuscript.
© Inter-Research 2021.
- North Atlantic-Arctic