抄録
An integration of the study of groundwater chemistry, numerical modeling, long-term bioreactor experiments, and in-situ sampling of activity growing microbes yields a portrait of subsurface anaerobe activity that differs sharply from conventional thinking. The chemical record of microbial activity on a groundwater’s redox chemistry in a well-studied aquifer is surprisingly incomplete, casting doubt on current methods of classifying subsurface microbial activity in aquifers. We find no evidence to support a concept by which subsurface microbial activity is arranged according to a thermodynamic ladder, nor do we find backing for the theory of competitive exclusion. Instead, we find strong evidence that iron reducing and sulfate reducing bacteria, previously considered locked in competition, are in fact forming mutualistic relationships in which they tightly cooperate. Where a group of microbes such as the methanogens is excluded from an ecosystem, the explanation is more likely ecologic than thermodynamic.
