A U‑Turn for Mercury Concentrations over 20 Years: How Do Environmental Conditions Affect Exposure in Arctic Seabirds?

• Main Authors: Sabrina Tartu (605762), Pierre Blévin (1719178), Paco Bustamante (288199), Frédéric Angelier (9212517), Claus Bech (380056), Jan Ove Bustnes (588693), Melissa Chierici (3071994), Agneta Fransson (471604), Geir W. Gabrielsen (380052), Aurélie Goutte (8762160), Børge Moe (414217), Christophe Sauser (5486996), Julien Sire (12041030), Christophe Barbraud (180267), Olivier Chastel (288198)
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 1753
• Subjects: Cell Biology; Genetics; Molecular Biology; Ecology; Inorganic Chemistry; Environmental Sciences not elsewhere classified; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; shrinking sea ice; nitrogen stable isotopes; upper trophic levels; fish community assemblage; u ‑ turn; high hg concentrations; hg concentrations followed; kittiwake diet could; 2000 – 2019; trophic level; prey community; kittiwake ’; could explain; hg concentrations; toxic contaminant; top predators; strong indicators; shaped trend; shaped associations; rearing black; primary productivity; norway ); new shift; methylated form; influence production; increasing trend; highly toxic; higher proportion; gradual input; global change; early 2000s; atlantic prey; associated release; arctic wildlife; arctic seabirds; arctic prey; 20 years; Arctic; Svalbard; Norway; rissa tridactyla; Sea ice
• Online Access: https://doi.org/10.1021/acs.est.1c07633.s001

Mercury (Hg) is highly toxic in its methylated form (MeHg), and global change is likely to modify its bioavailability in the environment. However, it is unclear how top predators will be impacted. We studied blood Hg concentrations of chick-rearing black-legged kittiwakes Rissa tridactyla (2000–2019) in Svalbard (Norway). From 2000 to 2019, Hg concentrations followed a U-shaped trend. The trophic level, inferred from nitrogen stable isotopes, and chlorophyll a (Chl a ) concentrations better predicted Hg concentrations, with positive and U-shaped associations, respectively. As strong indicators of primary productivity, Chl a concentrations can influence production of upper trophic levels and, thus, fish community assemblage. In the early 2000s, the high Hg concentrations were likely related to a higher proportion of Arctic prey in kittiwake’s diet. The gradual input of Atlantic prey in kittiwake diet could have resulted in a decrease in Hg concentrations until 2013. Then, a new shift in the prey community, added to the shrinking sea ice-associated release of MeHg in the ocean, could explain the increasing trend of Hg observed since 2014. The present monitoring provides critical insights about the exposure of a toxic contaminant in Arctic wildlife, and the reported increase since 2014 raises concern for Arctic seabirds.