Mercury contamination level is repeatable and predicted by wintering area in a long-distance migratory seabird. (15th November 2022)

• Record Type: Journal Article
• Authors: Bertram, Justine; Kürten, Nathalie; Bichet, Coraline; Schupp, Peter J.; Bouwhuis, Sandra
• Is Part Of: Environmental pollution. Volume 313(2022)
• Publication Date: 2022-11-15
• Subjects: Methylmercury -- Metal pollution -- Bird migration -- Individual repeatability -- Longitudinal study -- Hg; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.120107
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The environmental presence of mercury has dramatically increased over the past century, leading to increased uptake, especially by top predators such as seabirds. Understanding the exact sources of contamination requires an individual-level approach, which is especially challenging for species that migrate. We took such an approach and located the wintering areas of 80 common terns ( Sterna hirundo ) through tracking, and, across years, collected feathers grown in those areas to assess their mercury levels using atomic absorption spectrometry. Although feathers of males and females did not differ in their mercury level, we found the average feather mercury level to be highest in birds wintering in the Canary Current (3.87 μg g −1 ), medium in birds wintering in the Guinea Current (2.27 μg g −1 ) and lowest in birds wintering in the Benguela Current (1.96 μg g −1 ). Furthermore, we found considerable inter-annual fluctuations in feather mercury levels, a within-individual repeatability of 41%, that the mercury levels of 17% of feather samples exceeded the admitted toxicity threshold of 5 μg g −1, and that the overall mean concentration of 3.4 μg g −1 exceeded that of other published reports for the species. Further studies therefore should assess whether these levels lead to individual-level carry-over effects on survival and reproductive performance. Graphical abstract: Image 1 Highlights: 213 feather samples were collected from 80 common terns across 5 years. Individual repeatability of feather Hg levels was 75% within and 41% among years. Feather Hg levels differed between birds wintering in different areas. Hg levels in 17% of feather samples exceeded the admitted toxicity threshold.