Linking microbial community structure to biogeochemical function in coastal marine sediments: Stable isotope probing combined with magnetic bead capture

Microbial community structure and its biogeochemical functions in marine sediments can be successfully linked by using the improved Mag-SIP method in combination with other approaches. In this thesis, we were able to provide detailed information on the microorganisms responsible for the utilization of major substrates in marine sediments. It was shown that a number of important groups in the microbial community played a broader role than expected. Some surprising results are that oxygenic phototrophs such as benthic diatoms and Cyanobacteria are apparently capable of surviving under dark, anaerobic conditions through glucose fermentation, and that sulfate-reducing Deltaproteobacteria are important players in the high anaerobic chemoautotrophy rates detected in intertidal sediments.