Title: Temperature Sensitivity of Ecosystem Carbon Flux

Abstract: Temperature dependence of ecosystem carbon flux is a critical quantity for accurate prediction of future climate-carbon feedback. In this talk, I employed a variety of approaches, both theoretical and empirical, to estimate the temperature dependence of carbon flux in various ecosystems. First, I used a dynamic model of dissolved oxygen to estimate the temperature sensitivity of gross primary production and ecosystem respiration in streams across five biomes and predicted the changes in net ecosystem productivity in a warming climate.  Second, I used a three-year soil incubation experiment to determine the temperature sensitivity of soil respiration. I found that the apparent decrease in temperature sensitivity of soil respiration in response to warming could be explained by the temperature dependence of the Michaelis-Menten kinetics of soil enzymes. Finally, I used theoretical and simulation approaches to explore how the apparent temperature sensitivity of carbon fluxes changes when scaling up spatially, temporally, and over ecological organizations. Collectively, these studies demonstrated the importance of recognizing ecosystem carbon flux as a holistic and aggregated process. They also highlight the explicit description of the dynamics of carbon flux as a powerful tool to understand processes at the ecosystem level.