Abstract
It is well recognized that microbial diversity is enormous, and that only less than 1% of all bacteria in nature have been isolated in pure cultures. However, the value of this biodiversity for ecosystem functioning is still enigmatic. So far only a few studies have addressed one of the most burning questions in microbial ecology: How does nature permit the coexistence and survival in one and the same environment of so many species with the same or nearly identical type of metabolism? The proposed research will try to obtain insight in the ecological role of closely related coexisting bacterial populations that play an important role in the sulfur cycle, the sulfate reducing bacteria. For this purpose we will apply a polyphasic approach, including concepts and methods from microbiology, molecular biology and ecology to investigate the diversity, activity and dynamics of sulfate reducers in anaerobic bioreactors. Established as well as novel, state-of-the-art techniques, such as real-time PCR and molecular beacons, will be used for the first time to follow the expression of genes that encode important enzymes in the cycle, and so to infer the activity of particular populations under different well-controlled environmental conditions. The results of the proposed project will lead to a better understanding of the ecological role of sulfate reducers in natural and engineered ecosystems. In addition, we expect to be able to define a number of general principles of niche differentiation, and develop a theoretical model that can be tested in practice.
Netherlands