Global climate change is transforming bioenergetic landscapes, challenging organisms’ capacity to maintain energy balance. Repercussions are particularly profound in Arctic regions, where rates of warming exceed the global average by a factor of ~4. Animals can display plasticity in behavior and physiology, expanding the breadth of the ecological niche. However, there are limits to animals’ ability to make phenotypic modifications that support energetic homeostasis. The bioenergetic effects of climate change are attracting increasing research attention, but studies are still limited, especially in Arctic endotherms.
Furthermore, diverse chemical contaminants have neurotoxic, endocrine disrupting, and energetic effects that may interact with biological impacts of climate change to modify bioenergetic outcomes. Volatile and persistent chemical contaminants can reach remote regions through long-range transport mechanisms and bioaccumulate up food chains. Climate change is changing dynamics of contaminant cycling in Arctic ecosystems, which can result in increases in exposure. The Arctic Monitoring and Assessment Programme has highlighted elucidating joint effects of climate change and anthropogenic contaminants as a research priority.
The aim of this project (BioenergArc) was to contribute to this objective, using an Arctic seabird (Alle alle) as a model system, and to investigate the following questions: (1) Does contaminant exposure affect metabolic rate and thermoregulatory capacity in a fashion that could undermine capacity to cope with climate change? (2) How does environmental variation and contaminant exposure affect activity budgets and daily energy expenditure (DEE)? (3) Does variation in bioenergetic traits, potentially related to contamination levels, translate into fitness effects?
Several conclusions have resulted from this work. Among the most important are that changes in environmental conditions associated with climate change are transforming activity budgets of little auks, driving energetic costs upward. Behavioral plasticity currently appears to buffer fitness effects, but threatens to become unsustainable as temperatures continue to rise. In addition, results suggest important thermoregulatory implications of the changing cryosphere, with loss of sea ice as a resting substrate increasing thermoregulatory challenge during foraging trips at sea. Although Hg contamination was not associated with variation in activity budgets, DEE, or fitness, there was evidence for effects of Hg contamination on thermoregulatory dynamics. A literature review also revealed diverse avenues through which contaminants and climate change may interactively affect biological response variables.
