Predicting the effects of warming: from individual physiology to emergent ecosystem function

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Understanding how the physiology of individuals constrain ecosystem dynamics is of fundamental importance to predicting the effects of climate change on global biogeochemical cycles. My recent research demonstrates that rates of respiration accelerate at a faster pace than growth rates following acute increases in temperature. A direct, but unexplored consequence of this phenomenon is that the cost of growth increases with temperature, leading to the prediction that warmer environments should be characterised by less efficient energy transfer through food chains with less biomass at higher trophic levels. Here I propose to investigate this novel prediction with a research programme that involves the development and integration of metabolic, food web, and evolutionary theories with a series of experimental and field tests linking individual physiology to ecosystem and food web structure. Importantly, this is the first time in which short- (physiological) and long-term adaptation responses to warming will be measured for multiple interacting species comprising different trophic levels in order to predict and test emergent patterns at the ecosystem scale. This programme thus aims at delivering a predictive framework to help forecast how the functioning and dynamics of aquatic ecosystems will play out as the climate warms. Developing such an understanding is of both fundamental and practical importance. Fundamentally, this framework holds promise to reconcile the multiple mechanisms invoked to explain the effects of warming on ecosystem functioning, by teasing out the effects directly caused by energetic constraints. In practical terms, for example, such an understanding would also directly help improve ecosystem management under different climate change scenarios at regional scales by predicting changes in size distribution and ecosystem biomass composition.