Climate Change, Contaminants, Ecotoxicology and Overwintering Ecology of Arctic Seabirds Near Their Southern Range Limits (M20; 2020-22).

Arctic wildlife concurrently experience toxic contamination and rapid climate change. As Arctic temperatures warm, ice cover decreases: consequently, migratory animals may change where they overwinter, altering their contaminant exposure, and potentially further altering their migratory behaviour. Contaminants can disrupt hormones, behaviour and reproduction. There is growing evidence from our own research and the broader 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, seemingly limiting their ability to adjust to climate change. Building on this key result, we are studying year-round interactions between contaminants, climate change and ecotoxicology. We are further collaborating with Nunatsiavut Government biologists to characterize NCP-priority contaminants in over-wintering thick-billed murres hunted as Northern foods, and to better understand overwintering sources of priority contaminants. Our research focuses on the following NCP-priority contaminants: mercury (Hg), methyl-mercury, perfluorinated and historical brominated flame retardants. Our objectives are to: (1) determine these specific NCP-priority chemicals and stable isotopes in maternal blood, eggs and feathers of birds wearing geolocators (2019 only), or liver and feathers of breeding and overwintering murres (2020, 2021); (2) evaluate thyroid hormones, corticosterone, and oxidative stress in maternal blood (2019; matched to collected eggs); (3) examine associations among annual movements, hormone levels, contaminants and ice cover (2019-2021); (4) predict future contaminant levels based on predicted variation in ice cover from IPCC scenarios.