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、微生物生态和矿物风化之间的相互作用，重点是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野外方法，研究矿物成分对微生物生长的影响，以及微生物定居对矿物风化速率和养分释放的影响。拟议项目的具体研究目标是：1)检查原生生物在硅酸盐、表面蚀变硅酸盐和玄武岩上的就地定居行为，作为矿物表面特征和营养含量的函数；2)表征长石和玻璃结合的P、N和Fe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的速率作为微生物种群(类型和密度)和营养限制的函数；4)比较以磷灰石和磷灰石包裹体形式存在的P与存在于玻璃基质中的P的生物有效性。现场是营养有限的石油污染含水层、产甲烷湿地和褐质砂岩含水层。实验室微观世界将使用经过玻璃或矿物相改良的含水层沉积物作为无机营养的唯一来源，并表征群落结构、底物去除速率、生物量生产和矿物风化的变化。该项目的结果将深入了解矿物成分对地下微生物定植、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.