This proposal is designed to increase our understanding of the role played by soil organisms in carbon cycling under changing environmental conditions. One of the largest gaps in our understanding of ecosystem functioning lies in our understanding of how soil communities are impacted by environmental changes, and how these impacts feedback to alter plant community dynamics. Few studies have explicitly investigated the impact of multiple global change drivers on microbial communities and their control over carbon dynamics. In this study, we propose to quantify the long-term response of the microbial community to a suite of global change drivers, and test a conceptual model predicting carbon flow and fate in soil under elevated CO2 at the Jasper Ridge Global Change Experiment (JRGCE) facility. We will directly link carbon utilization and soil community composition using compound-specific 13C isotope signatures of microbial lipids, and will assess long-term changes in microbial functional potential. By increasing our understanding of the soil biological component, the results of this work will enhance our ability to predict ecosystem response to global-scale anthropogenic changes. In particular, it will increase our understanding of what controls soil carbon sequestration. Further, this project will be important in creating synthesis and synergy among research groups studying the effects of global-scale changes on terrestrial ecosystems. This type of interdisciplinary interaction is becoming increasingly important in studies of anthropogenic global changes.
