Biodiversity

Biography

Biography: Qianlai Zhuang

Abstract

This presentation will discuss how we have explicitly incorporated the effects of microbial activities on soil organic matter decomposition into a biogeochemistry model, the Terrestrial Ecosystem Model. Specifically, we will discuss how we have revised an existing Q10-based heterotrophic respiration algorithm, by incorporating the algorithms of Dual Arrhenius and Michaelis-Menten kinetics and microbial-enzyme interactions. The microbial physiology enabled model was then applied to quantify historical and future carbon dynamics of forest ecosystems in the conterminous United States and the Arctic. Our model simulations for the forest ecosystems in the United States demonstrate that the revised model better simulate historical ecosystem carbon dynamics. Another research effort has been made to incorporate a microbial dormancy into an explicit microbial-enzyme decomposition algorithm. The model was then used to examine soil carbon dynamics with and without representation of microbial dormancy. The model was finally extrapolated to global temperate forest ecosystems. Our study shows that the dormancy model consistently produced a better match with field-observed heterotrophic soil carbon effluxes than the no dormancy model. Currently, we are developing more detailed microbial physiologically based soil C and N models that shall improve the quantification of the land ecosystem C and N dynamics and their feedbacks to the global climate system.