Research aims

In our group we focus on microbial processes and communities in sediments and aquatic environments. We try to understand which bacteria and viruses are present in the microbial communities and how they interact with other bacteria and their environment. Primarily, we are not studying fossile residues of microbes but living microbial communities that are present in sediments with ages of more than 100.000 years and sometimes 500 m below the sea floor.

We combine classical microbiological techniques with molecular biological approaches. Since it is very difficult to grow bacteria from natural environment - especially those with extremely low growth rates - a lot of methodological work is done. We try to improve cultivation techniques and the molecular biological methods for analyzing bacterial communities and their phages.

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The bacteria we are most interested in are those of the sulfur cycle - either sulfate-reducing bacteria or phototrophic sulfur bacteria. We try to understand their life also by investigating physiological and bioenergetical aspects. Our research is embedded in the cooperation with the geochemical and modeling groups in our institute. Together we try to understand the processes going on in aquatic environments and sediments where bacteria constitute a significant portion of the living biomass on earth.

Special Equipment and Methods

  • Microscopy, Fluorescence Microscopy, Digital image analysis, Video
  • Microbe hunting machine (microcapillary controlled by a micromanipulator), used to isolate single cells under the microscope
  • Fermenters, used for continuous cultivation under anoxic conditions in the light or dark
  • Gas chromatography and HPLC with various detectors, suited for the analysis of numerous compounds
  • Polarography, used for the analysis of various reducible or oxidizable compounds
  • Microcalorimetry, able to detect heat production by microbial activities as low as a few W
  • Multi-electrode-chamber, equipped with sulfide, pH, platinum and oxygen electrodes for the study of various microbial acitivities
  • Needle Electrodes, used to measure oxygen, sulfide and pH gradients in sediments
  • PCR, DNA sequencer, DGGE for molecular biological work

Research Projects