Polar fish in a changing world: metabolic responses to multiple environmental stressors (PISCES)

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Both the Arctic and Antarctic ecosystem are progressively exposed to multiple anthropogenic environmental influences, e.g. ocean warming, ocean acidification and organic pollutants. The physiological performance of stenotherm, Antarctic notothenioid fish is evolutionary restricted to a very narrow thermal range over evolutionary timescales. These adaptations involve genetic and functional losses, which might be essential for the adaptation to environmental changes. In contrast, stenotherm Arctic gadoids been (evolutionary) exposed to a comparably more fluctuating habitat. Considering the evolutionary history of Arctic and Antarctic fish, they are likely to display different sensitivities to environmental changes.Generally, stenotherm fish possess only limited cardiorespiratory capacities for warm acclimation, and cardiac capacities are supposed to be a key factor in limiting the tolerance towards environmental changes. Studies also indicate negative and joint multi stressor impacts of ocean acidification and warming on embryos and larvae of polar species. Additionally, multiple stressors likely involve energetic trade-offs between basal maintenance and other essential energy requiring functions in fish.This project will evaluate how the multiple environmental stressors anthropogenic pollution, climate warming and ocean acidification will affect the energy metabolism (aerobic scope) of different life stages of Arctic and Antarctic fish. The central questions are: - Is there evidence that multiple stressors, i.e. warming and elevated pCO2 confine the chemical biotransformation capability of Polar fish? - Will multiple stressors cause shifts in the energy budget of Arctic and Antarctic fish?- How does toxicant exposure influence cardiac and aerobic performance in different life stages of polar fish?- What adverse outcomes are to be expected for gadoids and notothenioids from an ecological point of view?In an integrative approach, the proposal aims at providing a mechanistic understanding of molecular, mitochondrial, cellular, and metabolic processes that underlie and define the fish s vulnerability towards environmental stressors. Scopes for acclimation (as a measure for evolutionary adaptation potential) will be studied in various life stages of polar fish to identify the most sensitive developmental stages to environmental change.For a latitudinal comparison of tolerance to environmental factors the project will use stenotherm species comparable in terms of ecology and biology to obtain the best sensitivity data of Arctic vs. Antarctic species with a very different evolutionary history.To this end, the proposal aims at assessing the physiological vulnerability of Polar fish to climate change for future assessments of the actual risk of these fish towards anthropogenic stressors. Overall, the project will contribute to specify management, mitigation and conservation measures for the Polar ecosystems against on-going global change.