Groundwater Ecosystems: The Interdependence of Microbial Mineral Weathering and Population Diversity

地下水生态系统：微生物矿物风化和种群多样性的相互依赖詹妮弗·A·罗伯茨、大卫·格雷厄姆和威廉·D·皮克，堪萨斯大学雷切尔·奥布莱恩，阿勒格尼学院细菌在矿物风化中的参与现在是公认的，甚至是预期的地下地球化学组成部分。在超过3公里的深度和接近100摄氏度的温度下已经发现了微生物，越来越多的证据表明，这些微生物的生化功能可能是许多低温矿物风化反应背后的驱动力。然而，科学界才刚刚开始记录微生物催化的反应，出现了许多问题。负责任的生物体是否从风化反应中受益？矿物溶解如何影响定居微生物群落中的生物多样性？这种风化反应很可能从地质时代开始就起作用了。因此，了解这些现象和相关的生物，不仅可以直接了解周围环境的风化现象，还可以洞察微生物的进化和控制地下生物多样性的因素。这项工作有两个目标。首先，我们将使用来自六个不同地下水生态系统(温带阔叶林、热带森林、热带砍伐草原、温带高粱草原、北方湿地和热带湿地)的本地联合体来研究合成硅酸盐和天然硅酸盐相的营养驱动和金属抑制微生物风化作用。这项工作的结果将展示固相中微量营养物质和金属浓度如何影响微生物风化反应。其次，我们将在选定的一组地下水生态系统中确定微生物活动、群落组成和生物多样性的特征。根据这一特征，我们将研究由于营养和金属硅酸盐的引入和风化而导致的微生物种群演替。本项目的结果将深入了解硅酸盐结合的营养物质和金属对微生物风化的影响，以及矿物组成和风化反应如何影响各种地下水生态系统表层定植微生物群落的生物多样性。我们的研究还将阐明现代微生物风化过程是如何发挥作用的，反过来，可能有助于确定地质时期的关键过程。

Groundwater ecosystems: The interdependence of microbial mineral weathering and population diversityJennifer A. Roberts, David Graham, and William D. Picking, University of Kansas Rachel O'Brien, Allegheny CollegeParticipation of bacteria in mineral weathering is now an accepted, even expected component of subsurface geochemistry. Microorganisms have been found at depths exceeding 3 kilometers and at temperatures approaching 100C, and there is growing evidence that the biochemical functions of these organisms may be the driving force behind many low temperature mineral-weathering reactions. The scientific community has only begun documenting microbial-catalyzed reactions, however, and many questions arise. Do the responsible organisms benefit from weathering reactions? How does mineral dissolution affect biodiversity in colonizing microbial communities? Such weathering reactions have likely been operative since the beginning of geologic time. Therefore, understanding such phenomena, and the associated organisms, not only provides an immediate picture of ambient weathering phenomena, but might also provide insights into microbial evolution and factors that control subsurface biodiversity. There are two goals for this work. First, we will investigate nutrient-driven and metal-inhibited microbial weathering of synthetic and natural silicate phases using native consortia from a from six distinct groundwater ecosystems (temperate hardwood forest, tropical forest, tropical clearcut grassland, temperate tallgrass prairie, boreal wetland, and a tropical wetland). The results of this work will demonstrate how trace concentrations of nutrients and metals in the solid phase influence microbial weathering reactions. Second, we will characterize microbial activity, community composition, and biodiversity in a select group of groundwater ecosystems. Following this characterization we will examine the microbial population succession that results from the introduction and weathering of nutrient- and metal-bearing silicates.Results from this project will lend insight into the influence of silicate-bound nutrients and metals on microbial weathering, and how mineral composition and weathering reactions impact the biodiversity of the surface colonizing microbial community for a variety of groundwater ecosystems. Our investigations will also elucidate how modern microbial weathering processes function, and in turn, may help identify key processes through geologic time.