Microbial Geochemistry

研究重点将集中在地表水和地下水环境中微生物分类学和生理多样性与水文地球化学梯度时空动态之间的定量关系。在涉及氧化物和硅酸盐矿物的沉淀-溶解反应中，特别是在有助于从大气中去除二氧化碳的耦合过程中，微生物对铁氧化还原循环的生态生理多样性所起的作用迫在眉睫。研究将包括实验室和实地调查；实验室工作的一个主要优点是，它允许在广泛应用的热力学平衡和反应动力学原理的背景下，评估细菌对地球化学参数（如pH、氧化还原电位等）的依赖和影响。与此同时，实地研究不仅对建立理论模型的局限性、约束和有效性至关重要，而且还揭示了测试和利用实验室研究结果的机会，为新的实验方向的发展提供信息，有助于识别和评估关键的知识差距，并允许探索新的方法来破译复杂自然系统的行为。计划的工作范围包括地下水微生物群落的分子生物学和地球化学特征，微生物介导的氧化还原反应的定量电化学评估，以及建立微生物铁氧化还原转化速率、地下水地球化学、季节变化和地质环境（如基岩、覆盖层和含水层矿物学、冰川历史等）之间的相关性。这一举措代表着微生物地球化学向一个具有挑战性的新研究领域迈出了重要的一步，该研究领域专注于破译自然界微生物代谢多样性与地球化学过程之间存在的复杂时空关系，并了解与环境变化相关的干扰的潜在后果。

Research will focus on quantifying relationships between taxonomic and physiological microbial diversity and spatial-temporal dynamics of hydrogeochemical gradients in surface and groundwater environments. Of immediate concern is the role of ecophysiological diversity among of microorganisms for iron redox cycling in precipitation-dissolution reactions involving oxide and silicate minerals, particularly in terms of coupled processes that contribute to the removal of carbon dioxide from the atmosphere. Studies will encompass laboratory and field investigations; a major advantage of lab work is that it permits evaluation of the dependency and influence of bacteria on geochemical parameters such as pH, redox potential, etc., within the context of widely applied principles of thermodynamic equilibrium and reaction kinetics. At the same time, field studies are crucial not only to establish the limitations, constraints, and validity of theoretical models, but also reveal opportunities to test and exploit results of lab research, inform the development of new experimental directions, help to recognize and evaluate critical knowledge gaps, and permit exploration of new ways to decipher the behavior of complex natural systems. The planned scope of work includes molecular biological and geochemical characterization of groundwater microbial communities, quantitative electrochemical assessment of microbially mediated oxidation-reduction reactions, and establishment of correlations between rates of microbial iron redox transformations, groundwater geochemistry, seasonal variations, and geologic setting (e.g., bedrock, overburden and aquifer mineralogy, glacial history, etc.). This initiative represents an important step forward for microbial geochemistry into a challenging new area of research focused on deciphering the complex spatial and temporal relationships that exist between microbial metabolic diversity and geochemical processes in nature, and understanding potential consequences of disturbances associated with environmental change.