Ecological and Evolutionary Constraints on the Temperature Dependence of Microbial Community Respiration

The temperature dependence of microbial respiration remains one of the largest uncertainties in the response of the carbon cycle to climate change. Over short timescales, metabolic rates increase exponentially with temperature. A temperature-induced increase in microbial respiration will lead to an increase in the flux of carbon into the atmosphere, which may lead to more warming, resulting in a positive feedback. However, studies from multiple ecosystem types, have shown a decrease in the temperature sensitivity of community respiration under long-term warming. A dampened response of respiration to temperature would reduce or remove the positive feedback and current anthropogenic emissions would lead to less warming. The underlying ecological and evolutionary mechanisms that contribute to a dampening of the temperature sensitivity of microbial respiration are still up for debate and no consensus has been reached on their relative importance, hindering efforts to capture this important phenomenon in predictive models. The aim of the MICROADAPT project is to determine how rapid evolution and species sorting shape the temperature dependence of microbial community respiration using an array of innovative experiments with a microbial model system. In synergy with the experimental data, we develop novel mathematical theory that capture the ecological and evolutionary mechanisms that shape the emergent temperature response of microbial metabolism.