The purpose of this work is to enhance our understanding of important but 'unseen' processes in wetlands that influence climate. We will examine how plants and microbes interact below ground to regulate the production of methane, a powerful greenhouse gas that currently accounts for 20% of global warming. We suspect that there are important ecological interactions between plants, methane-producing bacteria (i.e. methanogens), and iron-reducing bacteria. Wetland plants create micro-niches in which their extensive root network provides organic carbon and introduces O2 into the predominately anoxic soil environment. These plant-driven factors appear to profoundly influence microbial community structure and the outcome of microbial competition. We will manipulate a freshwater wetland by removing plants and/or adding organic substrates, then track methane production, iron reduction, and other key microbial processes. In order to successfully link measurements of microbial activity and microbial community composition, we will use molecular techniques to track microorganisms that differ in key aspects of their physiology. We hypothesize that increases in methane production will be the result of microbial competition for resources and changes in microbial community structure. This information will help inform the development of process-based models of greenhouse gas emission from wetlands.
