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

天然气作为一种过渡性燃料正变得越来越重要，它的碳密集度和污染程度低于煤炭，以满足全球日益增长的能源需求。大约20%的天然气资源是由微生物产生的，这些微生物能降解煤层等地质构造中的有机物，并产生甲烷。最近的实验室和现场研究表明，可以刺激这些微生物产生新的天然气资源。然而，关于微生物如何将有机物自然转化为甲烷，产生新甲烷的速度，以及速度限制步骤，人们知之甚少。此外，从煤层中提取大量地下水来生产天然气，可能会改变现场的环境条件，对微生物群落造成未知的后果。本研究旨在确定不同水文和地球化学条件下煤层中微生物群落的结构和功能，以及它们随着地下水开采和煤层降水的变化情况。具体地说，我们将调查煤炭中微生物群落的空间、深度和时间变异性；这种分布如何受到水环境条件和可能反映在水和天然气同位素特征中的补给率的控制；微生物群落可能如何对地下水开采等扰动做出反应；以及如何将现场微生物活动的观测纳入煤炭生物转化为甲烷的预测模型。这项研究集中在怀俄明州/蒙大拿州的波德河盆地，该盆地是最早密集开发微生物煤层气的大型盆地之一，也是其他盆地未来煤层气开发的重要模式。这项研究的结果将通过NSF资助的CUAHSI水文服务器和蒙大拿州矿产和地质局地下水信息中心向公众公布。新的数据将被纳入基于网络的生物薄膜：超级教科书。而且，这项研究的视频将在亚利桑那大学佛兰多科学中心和生物圈2展出。

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.