STRUCTURE AND ACTIVITY OF MICROBIAL COMMUNITIES IN SEDIMENTS

Mineralization of organic matter in sediments are driven by a dense mi crobial population. Large chemical concentration gradients perpendicul ar to the interface are developed. Concentration profiles at the sedim ent-water interface can be measured in situ with miniaturized ion-sele ctive electrodes and fluxes, and reaction rates can be calculated with this information. Direct flux measurements in benthic chambers are pe rformed with isotope tracers to investigate the cycling of nutrients s uch as nitrogen and sulfur. With the development of molecular genetics new tools have become available to obtain information on the location and activity of microbial communities in the sediment. This opens a f ascinating field for collaboration between geochemists and microbiolog ists. Flux measurements based on microsensors and in situ incubation t echniques can now be related to microbiological information. In this c ontribution we give an overview of the current state of research in se nsor development, incubation techniques, and molecular genetics at EAW AG.