Collaborative Research: Geochemical Controls on the Microbial Regulation of Arsenic Cycling in Geothermal Systems

砷是一种剧毒的无机元素，自然存在于地壳中。因此，某些环境条件可能导致土壤、流域和/或饮用水供应受到污染。因此，人们对确定控制自然系统中砷循环的化学和生物因素非常感兴趣。在本研究中，黄石国家公园的地热环境将作为模型系统，以了解地球化学和微生物对自然系统中砷转化的控制。黄石火山口包含了多种不同的化学环境，砷是许多地热流出物的重要成分，导致砷大量输入到当地的流域。这个地球化学、微生物学和遗传学的合作项目将评估地热系统中微生物介导的砷转化速率的地球化学控制，并利用定量分子工具确定负责砷转化的特定基因的作用。我们希望根据地球化学条件，确定具有氧化或还原砷能力的特定微生物，这些微生物是黄石国家公园特定地热环境的重要成员。这些结果将有助于了解微生物对全球砷循环的贡献。此外，这项工作将直接有助于地球生物学计划的优先事项，包括生物和地质系统之间的相互作用，以及对微生物群在塑造地球进化史中的作用的理解。

Arsenic is a highly toxic inorganic element that is found naturally in the Earth's crust. As a result, certain environmental conditions can lead to the contamination of soils, watersheds and or drinking water supplies. Consequently, there is significant interest in determining the chemical and biological factors that control arsenic cycling in natural systems. In the current study, geothermal environments in Yellowstone National Park will be used as model systems to understand geochemical and microbiological controls on arsenic transformations in natural systems. The Yellowstone caldera contains an enormous diversity of different chemical environments and arsenic is an important constituent in many geothermal outflows, resulting in significant inputs of arsenic to local watersheds. This collaborative project in geochemistry, microbiology and genetics will evaluate geochemical controls on the rates of microbially-mediated arsenic transformation in geothermal systems, and employ quantitative molecular tools to determine the role of specific genes responsible for the transformation of arsenic. We expect to identify specific microorganisms with capabilities to oxidize or reduce arsenic, and that are important members of specific geothermal environments of Yellowstone National Park, depending on geochemical conditions. These results will assist in understanding the microbial contributions to global arsenic cycling. Further, this work will contribute directly to priorities of the Geobiology program including interactions between biological and geological systems, and an understanding of the role of microbiota in shaping Earth's evolutionary history.