Silicates, Silicate Weathering, and Microbial Ecology
نویسندگان
چکیده
Mineralogy, microbial ecology, and mineral weathering in the subsurface are an intimately linked biogeochemical system. Although bacteria have been implicated indirectly in the accelerated weathering of minerals, it is not clear if this interaction is simply the coincidental result of microbial metabolism, or if it represents a speci c strategy offering the colonizing bacteria a competitive ecological advantage. Our studies provide evidence that silicate weathering by bacteria is sometimes driven by the nutrient requirements of the microbial consortium, and therefore depends on the trace nutrient content of each aquifer mineral. This occurrence was observed in reducing groundwaters where carbon is abundant but phosphate is scarce; here, even resistant feldspars are weathered rapidly. This suggests that the progression of mineral weathering may be in uenced by a mineral’s nutritional potential, with microorganisms destroying only bene cial minerals. The rock record, therefore, may contain a remnant mineralogy that re ects earlymicrobial destruction of biologically valuableminerals, leaving a residuum of “useless”minerals, where “value” depends on the organism, its metabolic needs, and the diagenetic environment. Conversely, the subsurface distribution of microorganisms may, in part, be controlled by the mineralogy and by the ability of an organism to take advantage of mineral-bound nutrients.
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a Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115, USA b Department of Environmental Earth System Sciences, Stanford University, Stanford, California 94305-2115, USA c Department of Evolutionary Biology and Ecology, Brown University, Providence, RI 02912, USA d Geological Institute, Eldgenössische Technische Hochschule Zürich, 8092 Züric...
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