Polar fish in a changing world: metabolic responses to multiple environmental stressors (PISCES)
Final Report Abstract
Both the Arctic and Antarctic ecosystem are progressively exposed to multiple anthropogenic environmental influences, e.g. ocean warming, ocean acidification and organic pollutants. Considering the evolutionary history of Arctic and Antarctic fish, they are likely to display different sensitivities to environmental changes. This project aimed to evaluate how the multiple environmental stressors anthropogenic pollution, climate warming and ocean acidification would affect the energy metabolism (aerobic scope) of different life stages of Arctic and Antarctic fish. The central questions were: Is there evidence that multiple stressors, i.e. warming and elevated pCO2 confine the chemical biotransformation capability of Polar fish? Do multiple stressors cause shifts in the cellular energy metabolism, which underlies the energy budget, in Arctic and Antarctic fish? How does toxicant exposure influence cardiac and aerobic performance in different life stages of polar fish? What adverse outcomes are expected for gadoids and notothenioids from an ecological point of view? In an integrative approach, the proposal aimed at providing a mechanistic understanding of molecular, mitochondrial, cellular, and metabolic processes that underlie and define the fish’s vulnerability towards environmental stressors. In the first part of the project, the study investigated the effect of climate change and intensifying anthropogenic activities, on Polar cod (Boreogadus saida), which plays a key role in the Arctic marine ecosystem and serves as important monitoring species for combined impacts of environmental pollution and global warming. Potential effects of acute PAH and thermal exposure were therefore examined by respiration measurements of isolated hepatocytes. The outcomes of these experiments suggested that Polar cod is capable of metabolizing pollutants under environmental conditions to avoid negative effects on cellular functions. High temperature exposure resulted in a beginning energy allocation towards enhanced detoxification mechanisms. As a consequence, increasing water temperatures and pollution in the Arctic Ocean will probably enforce cellular stress responses in Polar cod. This study highlighted the importance of combined investigations on these stressors to better predict harmful consequences for Arctic marine fish.
