Dissertation Research: Microbial Community Structure and Ecosystem Function: Linking Methanogen Community Composition to Methane Production Rates in Wetland Soils

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This study will explore the relationship between the community of microbes present and the production of methane in peatlands in northern Michigan. Peatlands produce significant amounts of methane, a powerful greenhouse gas that traps 25 times more heat than carbon dioxide per unit weight, and drives almost a fifth of human-caused global climate change. Methane is produced by methanogens, a group of microorganisms in the domain Archaea, via two pathways. These pathways are carried out by distinct groups of methanogens, so understanding the relationship between the methanogens present and methane production rates is essential to understanding the contribution of peatlands to future global climate change. Because the overwhelming majority of methanogens remain unculturable, it is necessary to use a culture-independent, gene-based approach to identify the methanogens present in the environment. For these investigations, mcrA, a gene involved in methanogenesis in all known methanogens, will be used as a molecular marker. mcrA DNA and mRNA from peat samples will be sequenced to identify the methanogens present, and to quantify their biodiversity. The use of high-throughput sequencing will allow an unprecedented level of replication across space and through time, and the resulting methanogen data will be correlated to measured rates of methanogenesis in the peat samples, along with environmental factors such as temperature, pH, and water chemistry. This doctoral dissertation improvement project will contribute to the understanding of methane production rates in boreal peatlands, a highly significant source of this greenhouse gas. In addition to enhancing the training of a doctoral student, this project will provide research experience for several undergraduates including those from groups underrepresented in science.