Hydrothermal vents are ideal model biotopes for microbiological studies because these habitats combine various moderate to extreme environmental conditions:
Life in deep-sea hydrothermal provinces is based on local primary production. Indigenous biomass synthesis is fueled by biological oxidation of reduced inorganic compounds, such as hydrogen, reduced sulfur or metal compounds. These substrates are provided by hot, reduced hydrothermal fluids, which ascend from inner earth. As the reduced emissions rise they are admixed with ambient, cold, oxygenated seawater. The contact of reduced, hot hydrothermal fluids with oxygenated, cold seawater results in the development of thermal and chemical gradients. Hence, hydrothermally influenced biotopes are hallmarked by highly diverging thermal and chemical features, ranging from extremely hot to cold (4°C) and fully reduced to fully oxic conditions. Conclusively, enzymatic inventories of indigenous microbes are adapted to dealing with the local extreme conditions.
With 70% of our planet’s surface being covered by marine sediments, they represent the largest reservoir of organic carbon on Earth and play a pivotal role for global carbon cycling. Although coastal sediments cover a relatively small area of the seafloor (9%), they account for most of the organic carbon decomposition (87%), primarily buried in anoxic sediments. Given the relevance of anoxic sediments for sequestering carbon, it is more than crucial to understand the underlying microbial processes.
In conjunction with microbial processes from these environments the results from our research have two major scopes: One addresses biogeochemical and ecological questions surrounding bio-geo-coupling, the other deals with the applicability of novel enzymes for industrial application.
Bio-geo-coupling processes. One of our key goals is to better understand how abiotic dynamics but also biotic interactions affect microbial diversity, activity, and metabolic strategies. Currently we are focusing on how different inorganic electron donors and electron acceptors and their availability influence chemosynthetic microorganisms and element turnover.
Industrial Application. Engaging in ecological questions entails seeking novel enzymes with selected functions. Our emphasize lies on [NiFe] hydrogenases (catalyzing H2 ↔ 2H+ + 2e–) and carbon monoxide dehydrogenases (CODH) (catalyzing CO + H2O + A ↔ CO2 + AH2). If immobilized on surfaces hydrogenases can be useful for (i) production of hydrogen as an energy carrier (fuel storage in electrochemical cell) and (ii) oxidation of hydrogen as an energy source (fuel cell). CODH can produce carbon monoxide, which has a significant fuel value and is also used as feedstock for different synthetic reactions. Aside CO2 concentrations can be reduced in flue and other waste gases.