Mercury exposure in an endangered seabird: long-term changes and relationships with trophic ecology and breeding success

Mills, W. F., Bustamante, P., McGill, R. A.R. , Anderson, O. R.J., Bearhop, S., Cherel, Y., Votier, S. C. and Phillips, R. A. (2020) Mercury exposure in an endangered seabird: long-term changes and relationships with trophic ecology and breeding success. Proceedings of the Royal Society of London Series B: Biological Sciences, 287(1941), 20202683. (doi: 10.1098/rspb.2020.2683) (PMID:33352077)

Abstract

Mercury (Hg) is an environmental contaminant which, at high concentrations, can negatively influence avian physiology and demography. Albatrosses (Diomedeidae) have higher Hg burdens than all other avian families. Here, we measure total Hg (THg) concentrations of body feathers from adult grey-headed albatrosses (Thalassarche chrysostoma) at South Georgia. Specifically, we (i) analyse temporal trends at South Georgia (1989–2013) and make comparisons with other breeding populations; (ii) identify factors driving variation in THg concentrations and (iii) examine relationships with breeding success. Mean ± s.d. feather THg concentrations were 13.0 ± 8.0 µg g−1 dw, which represents a threefold increase over the past 25 years at South Georgia and is the highest recorded in the Thalassarche genus. Foraging habitat, inferred from stable isotope ratios of carbon (δ13C), significantly influenced THg concentrations—feathers moulted in Antarctic waters had far lower THg concentrations than those moulted in subantarctic or subtropical waters. THg concentrations also increased with trophic level (δ15N), reflecting the biomagnification process. There was limited support for the influence of sex, age and previous breeding outcome on feather THg concentrations. However, in males, Hg exposure was correlated with breeding outcome—failed birds had significantly higher feather THg concentrations than successful birds. These results provide key insights into the drivers and consequences of Hg exposure in this globally important albatross population.

• Item Type: Articles
• Additional Information: W.F.M. is supported by a NERC GW4+ Doctoral Training Partnership studentship from the Natural Environment Research Council (NERC; grant no. NE/L002434/1). Stable isotope analyses were funded by the NERC Life Sciences Mass Spectrometry Facility (grant no. EK311-12/18). The Institut Universitaire de France (IUF) is acknowledged for its support to P.B. as a Senior Member.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McGill, Dr Rona
• Authors: Mills, W. F., Bustamante, P., McGill, R. A.R., Anderson, O. R.J., Bearhop, S., Cherel, Y., Votier, S. C., and Phillips, R. A.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Proceedings of the Royal Society of London Series B: Biological Sciences
• Publisher: The Royal Society
• ISSN: 0962-8452
• ISSN (Online): 1471-2954
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Proceedings of the Royal Society of London Series B: Biological Sciences 287(1941): 20202683
• Publisher Policy: Reproduced under a Creative Commons License
• Data DOI: 10.5061/dryad.vdncjsxsq