Climate change, contaminants, ecotoxicology and overwintering ecology of Arctic seabirds near their southern range limits (M20; 2019-20).

Toxic contamination in Arctic wildlife is occurring against rapid climate change. As Arctic temperatures warm, ice cover is decreasing, and consequently, migratory animals change where they overwinter that may alter their contaminant exposure and further alter migratory behaviour, creating a positive feedback loop. Contaminants can disrupt hormones, behaviour and reproduction. There is growing evidence from our own research and the wider literature that contaminants disrupt hormones associated with migration and breeding. Since 2016, we showed mercury impacted foraging behaviour of Arctic seabirds by impacting thyroid hormones, limiting their ability to adjust to climate change. Building on that key result, we will study year-round interactions between contaminants, climate change and ecotoxicology, with the following specific objectives: (1) determine mercury (Hg) and methyl-mercury in eggs laid by birds wearing geolocators; (2) evaluate thyroid hormones, corticosterone, oxidative stress, Hg and NCP-priority compounds in blood of the same females laying these eggs; (3) attach additional geolocators to examine overwintering behavior, intending to collect and analyze their eggs in 2020; (4) examine associations among movement, hormone levels, contaminants and ice cover; (5) predict future contaminant levels based on predicted variation in ice cover from IPCC scenarios.