CMG Research: Impact of Mineral Precipitating Biofilms on the Physical and Chemical Characteristics of Porous Media

拟议的工作将开发实验室，建模和计算工具，用于研究矿物沉淀微生物群落的地质影响，旨在阐明基本原理并提供多孔介质中碳酸盐矿物沉淀生物膜的水文生物地球化学条件和过程的定量描述。结果将是(1)表征重要的物理（例如平流和扩散运输），化学（例如pH分布）和生物（例如微生物代谢活动）影响孔隙系统的现象，以及(2)开发测量技术，以确定具有适当空间和时间分辨率的相关参数。为了实现这一目标，将构建模型，以便在描述生物膜与多孔介质相互作用所需的细节中观察和洞察流体动力学，化学，电化学，微生物学和热力学的作用。热力学原理将用于改进描述生物膜作为热力学机器的自然地球化学作用所必需的。将采用的实验系统将允许在毛细管和多孔介质流动反应器中对生物膜发育和矿物沉淀进行空间和时间分辨的非破坏性观察。它们将有助于缩小现有的非流动（批）系统之间的知识差距，通常用于阐明生物地球化学过程和经常观察到的中观和宏观尺度上流体动力学对生物地球化学过程的影响。提出的研究重点是微生物诱导的碳酸钙矿化。在浅海和深海（如珊瑚礁、藻类和硅藻外骨骼）和陆地环境中，碳酸钙的形成是巨大尺度特征发展的原因。碳酸盐岩（如石灰岩、大理石和白垩）可能是地球上最大的单一无机碳储集层，其碳含量约为6500万亿吨。碳酸盐矿物的形成和溶解是全球碳循环的重要组成部分，有可能结合或释放大量二氧化碳，因此可能影响全球气候。此外，工程的、微生物介导的碳酸盐沉淀已被提出作为一种策略，以改善地质碳固存，并促进重金属和放射性核素从污染的地下水中沉淀。研究人员将开发实验室和计算工具，以更好地了解微生物群落在所有这些过程中的作用和利用环境中的潜力。

The proposed work will develop laboratory, modeling and computational tools for the study of the geological impact of mineral precipitating microbial communities, aiming at elucidating fundamentals and providing quantitative descriptions of the hydrobiogeochemical conditions and processes in carbonate mineral precipitating biofilms in porous media. Outcomes will be (1) characterization of the important physical (e.g. advective and diffusive transport), chemical (e.g. pH distribution), and biological (e.g. microbial metabolic activity) phenomena impacting pore systems, and (2) development of measurement techniques for identified relevant parameters with suitable spatial and temporal resolution. To accomplish this, models will be constructed that allow observation and insight into the roles of hydrodynamics, chemistry, electrochemistry, microbiology, and thermodynamics in the detail that are needed for description of interaction of biofilms with porous media. Thermodynamic principles will be used, necessary for improved description of biofilms in their natural geochemical role as thermodynamic machines. The experimental systems to be employed will allow spatially and temporally resolved non-destructive observation of combined biofilm development and mineral precipitation in capillary and porous media flow reactors. They will aid in closing the existing gap of knowledge between non-flowing (batch) systems often used to elucidate biogeochemical processes and the frequently observed influence of hydrodynamics on biogeochemical processes on the meso- and macroscale.The proposed research focuses on microbially-induced calcium carbonate mineralization. Calcium carbonate formation is responsible for the development of features with enormous scales in the shallow and deep ocean (e.g. reefs and alga and diatom exoskeletons) and in the terrestrial environment. Carbonate rocks (such as limestone, marble, and chalk) are probably the single largest reservoir of inorganic carbon on earth containing approximately 65 million gigatons of carbon. Carbonate mineral formation and dissolution are important parts of the global carbon cycle, have the potential to bind or release large amounts of carbon dioxide, and may therefore affect the global climate.Additionally, engineered, microbially mediated carbonate precipitation has been proposed as a strategy to improve geologic carbon sequestration and to facilitate the precipitation of heavy metals and radionuclides from contaminated groundwater. The investigators will develop laboratory and computational tools to better understand the role and utilize the potential in the environment of microbial communities in all of these processes.