The Stable Isotope Geochemistry and Aquatic Biogeochemistry Group studies the biogeochemical cycles of biologically important elements and their isotopes in marine and freshwater systems. More precisely, we study the distribution of various elements, their chemical speciation and their stable isotope ratios in natural aquatic systems, providing information as to the mechanisms that underlie the observed patterns. Observations are often calibrated by studying the relevant biogeochemical processes in the laboratory, using culture incubations, and put into a quantitative framework, using numerical models. The focus of most recent research activities are the global and regional nitrogen (N) cycles in general, and the fractionation of nitrate isotopes (N and O) in the natural nitrogen cycle, as well as the application of nitrate isotopes to identify and quantify microbial nitrogen transformation reactions in aquatic systems, soils and sediments in particular. Another focus of ongoing investigations is the cycling and bacterial degradation of organic matter in aquatic environments, its role in the generation of permanently or temporarily hypoxic and suboxic environments, as well as its impact on solute exchange and redox reactions at the sediment-water interface of marine and lacustrine environments. Of particular interest is the microbially mediated generation and consumption of green house gases, such as methane and N
2O.
Investigated ecosystems are lakes, groundwater aquifers, riverine catchments and estuaries, the open ocean and coastal marine environments, as well as hydrothermal vent and cold seep systems in the deep ocean.
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© 2010 Departement Umweltwissenschaften - Umweltgeowissenschaften - Universität Basel
