106 Groundwater Microbial Communities

Abstract

Microbial communities in aquifers consist of diverse interactive individuals which break down complex organic matter for metabolic energy. Microbes are adapted to function over environmental conditions ranging from freezing to boiling, acidic to alkaline. They can use oxygen as a reducible metabolite during organic carbon oxidation, but, since oxygen is rapidly depleted in subsurface environments, different groups of organisms may also rely upon other compounds such as reducible metals or upon fermentation. Community members are interdependent, but compete for resources, and communities often have predominant groups that rely on recognizable chemical pathways such as sulfate reduction. The predominant group varies spatially and temporally, as the available nutrients change or are depleted.