Microbial Weathering of Silicates: Aggressive Release of Limiting Nutrients

该项目将研究浅层地下水中矿物化学、微生物生态学和矿物风化之间的相互作用，重点研究长石在营养有限的地下水中的营养潜力。该项目将使用实验室和实地方法，审查矿物成分对微生物生长的影响，以及微生物定殖对矿物风化率和养分释放的影响。该项目的具体研究目标是：1)研究原生生物在硅酸盐、表面蚀变硅酸盐和玄武岩上的原位定殖行为与矿物表面特征和营养成分的关系；2)表征长石和玻璃结合的磷、氮和铁对微生物生长和基质利用率的影响；3)（表征矿物溶解和养分释放速度作为微生物种群（类型和密度）和养分限制的函数；4）比较磷灰石和磷灰石包裹体中存在的磷与玻璃基质中存在的磷的生物利用度。油田地点为营养有限的石油污染含水层、产甲烷湿地和木质素砂岩含水层。实验室微观环境将利用经玻璃或矿物相修正的含水层沉积物作为无机营养物的唯一来源，并对群落结构、基质去除速率、生物量生产和矿物风化的变化进行表征。该项目的研究结果将有助于了解矿物组成对地下微生物定植、群落结构和生存的影响，以及微生物在具有生物价值的特定矿物的早期和快速风化过程中的作用。

9903267BennettThe project will investigate the interplay between mineral chemistry, microbial ecology, and mineral weathering in shallow ground waters, focusing on the nutrient potential of feldspars in nutrient limited ground waters. The project will examine the influence of mineral composition on microbial growth, and the resultant influence of microbial colonization on mineral weathering rate and nutrient release, using both laboratory and field methods. Specific research objectives for the proposed project are to 1) examine the in situ colonization behavior of native organisms on silicates, surface-altered silicates, and basalts as a function of mineral surface characteristics and nutrient content; 2) characterize the influence of feldspar and glass-bound P, N, and Fe on microbial growth and the rate of substrate utilization, 3)(characterize the rate of mineral dissolution and nutrient release as a function of microbial population (type and density) and nutrient limitation and 4) compare the bioavailability of P present as apatite and apatite inclusions to P present in a glass matrix. The field sites are a nutrient-limited petroleum contaminated aquifer, a methanogenic wetland, and a lignitic sandstone aquifer. Laboratory microcosms will use aquifer sediments amended with glass or mineral phases as the sole source of inorganic nutrients, and changes in community structure, rate of substrate removal, biomass production, and mineral weathering characterized. The results of this project will provide insight on the influence of mineral composition on microbial colonization, community structure, and survival in the subsurface, and the role of microorganisms in the early and rapid weathering of specific minerals of biologic value.