Our research is related to biogeochemical processes in aquatic ecosystems. Experimental data from laboratory studies as well as detailed observations from natural systems form the basis for interpretation supported and conveyed by application of mathematical modeling.
- Redox processes within chemical hot spots
Although many studies have investigated the degradation of contaminants in aquatic systems we know only little about the specific process occurring within microbial hot spots. Here we have developed the hypothesis that chemical hot-spots control biogeochemical processes in heterogeneous aquifers (Cooperation with DTU and GEUS, Denmark).
- Effect of low dissolved organic carbon (DOC) concentrations in shallow and deep groundwater systems
Groundwater systems are generally poor in organic carbon. Therefore it is hard to imagine that the enormous amounts of biomass living in the subsurface depend on the little dissolved DOC. Here we want to study the effect of different electron donor/ acceptor interactions in surface-water and groundwater systems to understand the turnover processes of nitrogen and sulfate in DOC limited aquatic ecosystem. This topic is performed in close cooperation with the Helmholtz Center Munich, Institute of Ecological Chemistry (Dr. Hertkorn, Dr. Schmidt-Kopplin) and the Limnologische Station of TUM (Prof. Geist).
- Stable isotope fractionation
One of our most important tools for the identification and quantification of biogeochemical processes in complex aquifers represents the stable isotope technique. Here we want to investigate the principal mechanism of stable isotope fractionation with focus on the environmental parameters controlling the extent of stable isotope fractionation during denitrification. In cooperation with the Institute of Groundwater Ecology, Helmholtz Center Munich (Dr. Elsner) and international partners we perform laboratory and field experiment to learn more about the use of stable isotopes in biogeochemistry.
- Modeling of groundwater-plant interactions
Although plants play an important role in the water cycle and may also significantly impact the fate of substances in the subsurface, feedback mechanisms between plants and hydrological systems have received little attention to date. We therefore aim at coupling dynamic plant uptake models to reactive leaching and groundwater transport simulation (in cooperation with Prof. Mayer, UBC, Canada).
- Microbial growth and biodegradation coupled to diffusion processes and plant uptake
Biodegradation of contaminants at the field-scale is often limited. Therefore contaminants present in soil or groundwater may pose considerable threats to ecosystems and human health. Our aim is to investigate contaminant fate in the soil-groundwater-plant systems. Experiments and field observations are analyzed mathematically in order to understand and describe relevant processes and parameters driving and limiting biodegradation. Investigations are performed in cooperation with DTU, Denmark (Prof. Trapp) and UFZ, Leipzig (Prof. Kästner).