Sooty terns as large-scale bioindicator of mercury contamination in marine ecosystems: A pantropical approach
Year: 2026
Type: article
Abstract: ABSTRACT Mercury (Hg) is a toxic contaminant, which poses serious threats to both wildlife and humans worldwide. Although tropical oceans receive half of the world’s atmospheric Hg depositions, its biomonitoring is largely overlooked in these ecosystems. This study provides a comprehensive, pantropical assessment of Hg contamination of marine ecosystems, using the sooty tern ( Onychoprion fuscatus ) as bioindicator. Total Hg concentrations were measured from feathers, collected in 28 colonies across all tropical oceans (2003-2022), from adults (n=564) and chicks (n=407), to evaluate longer- and shorter-term contamination. To investigate the role of bird trophic ecology on Hg contamination, bulk stable isotopes of carbon (δ 13 C) and nitrogen (δ 15 N) were also analysed, as respective proxies for feeding habitat and diet. Because baselines of stable isotopes may vary at large spatial scales, compound-specific nitrogen stable isotope analyses of amino-acids were performed on a subset of adults (n=91, 19 colonies), to calculate their trophic position (TP), accounting for both baseline and trophic effects. As expected, Hg concentrations were higher in adults than chicks, because of their shorter bioaccumulation period. Overall, colonies from the Northern Hemisphere exhibited the highest Hg concentrations, consistently with higher historical anthropogenic emissions of Hg in the North. Models revealed that Hg contamination was driven by environmental contamination (colony location, feeding habitat) rather than diet (TP), which remained similar across the pantropical range. Our findings provide important baseline data for tropical marine ecosystems and underscore the need for enhanced monitoring in regions, where gold-mining and changing oceanographic conditions will likely modify future Hg exposure.
Source: Journal of Hazardous Materials
Authors: Fanny Cusset, Mickaël Charriot, Pierre Richard, Jérôme Fort, Leandro Bugoni, Nicholas Carlile, Annabelle Cupidon, Nina da Rocha, Antonio Garcia-Quintas, Gaël Guillou, Matthew Morgan, Terence O’Dwyer, Patricia Luciano Mancini, Verónica Costa Neves, Gerard Rocamora, Laura Shearer, Eduardo Ventosa, Yves Cherel, Paco Bustamante
Institutions: Centre National de la Recherche Scientifique, Centre d'Etudes Biologiques de Chizé, LIttoral ENvironnement et Sociétés, La Rochelle Université, Universidade Federal do Rio Grande, Island Conservation Society, Ifremer, Université de Bretagne Occidentale, Centro de Investigaciones de Ecosistemas Costeros, Laboratoire des Sciences de l'Environnement Marin, Institut de Recherche pour le Développement, Université de Bretagne Occidentale, Universidade Federal do Rio de Janeiro, Universidade dos Açores, Instituto de Investigação em Ciências do Mar Okeanos, University of Seychelles, Institut Universitaire de France
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,340
Funders: BirdLife Australia, Institut de Recherche pour le Développement, International Council for Canadian Studies, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Institut Universitaire de France, La Rochelle Université, U.S. Fish and Wildlife Service, Fundação para a Ciência e a Tecnologia, European Regional Development Fund, Instituto Chico Mendes de Conservação da Biodiversidade
OpenAlex ID: W7129370888