Collaborative Research: Hydrodynamic controls on microbial community dynamics and carbon cycling in coalbeds

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Natural gas is becoming increasingly important as a transitional fuel, less carbon-intensive and polluting than coal, to meet growing energy demands worldwide. Approximately 20% of natural gas resources are generated by microbes that degrade organic matter in geologic formations, such as coal seams, and produce methane. Recent laboratory and field studies have shown that these microorganisms can be stimulated to generate new gas resources. However, little is known about how microbes naturally convert organic matter into methane, the rates new methane can be generated, and the rate limiting steps. In addition, large quantities of groundwater are extracted from coal seams to produce natural gas, which may alter the in situ environmental conditions with unknown consequences for the microbial communities. This study aims to determine the structure and function of microbial communities in coal seams under different hydrologic and geochemical conditions, and how they may change with groundwater pumping and dewatering of coal beds. Specifically, we will investigate the spatial, depth and temporal variability of microbial communities in coals; how this distribution is controlled by aqueous environmental conditions and recharge rates that may be reflected in water and gas isotopic signatures; how microbial communities may respond to perturbations, such as groundwater extraction; and how observations of in situ microbial activity can be incorporated into a predictive model of coal bioconversion to methane. The study is focused in the Powder River Basin in Wyoming/Montana, one of the first large basins to undergo intensive development of microbial coalbed methane (CBM), and an important model for future CBM development in other basins. Results from this study will be made available to the public via the NSF-funded CUAHSI Hydroserver and Montana Bureau of Mines and Geology Ground Water Information Center. New data will be incorporated into the web-based Biofilms: the Hypertextbook. And, a video on the research will be on display at the University of Arizona Flandrau Science Center and Biosphere2.