Climate change and plastic-related contaminants: interactive effects of multiple stressors on Arctic seabirds near their southern range limits across their annual cycle (M20; 2023-2026).

Arctic wildlife behaviour and ecology is modified by interacting multiple stressors including rapid climate change that impacts ice conditions and contaminants. Migratory animals, such as seabirds, must adapt and alter their use of land- and seascapes throughout the year, in relation to the decreasing sea ice cover from the warming Arctic temperatures. These multiple stressors are also interactive: with warming, some contaminants increase or decrease, and with changing migration, wildlife may be exposed differentially to contaminants with varying impacts to migrating wildlife. Thick-billed murres, an Arctic seabird, breeding at Akpatuurjuaq (Coats Island, Hudson Bay) have been outfitted with biologgers to track their movement through their annual cycle to identify and understand where and when seabirds are impacted by climate change and contaminants, and thus infer when, where, and how, sea ice conditions influence migration and contaminant impacts. In each of three years, ingested microplastics, plastics-related organophosate esters (OPEs), UV-stabilizers (e.g., UV-328), per- and poly-fluorinated alkyl acids (PFAS), and mercury, and possible related effects, will be analyzed in tissues collected from seabirds when breeding at Akpatuurjuaq and when overwintering near Nain, Nunatsiavut. Eggs and maternal (and paternal) blood samples provide temporal insights into contaminants accumulated during spring migration-arrival at Akpatuurjuaq (eggs) and several weeks later in the middle of the incubation period (blood samples), while liver samples of overwintering, community-harvested murres provide information on exposure and accumulation of contaminants during fall migration and early winter staging, as well as providing information on immediate and long-term country food security. Post-Doctoral Fellow and NSERC Banting Scholarship Recipient, Dr. Anis Mdieu, is actively involved in all aspects of this research, including coordinating collaborators, field work collections, and preparing related reports and scientific peer-reviewed publications from this research (2023-2026) and relevant, previous results (2019-2022). The species migration patterns will be modeled in response to environmental conditions, comparing these patterns to contaminant concentrations reflecting differential seasonal contaminant exposure, to determine where and when these birds accumulate NCP-priority pollutants annually and the influence of changing sea ice conditions.