The aim of the research group is the understanding of the role of interfaces and colloids in biogeochemical processes. One focus lies on biogeochemical interactions within the plant-soil compartment and their coupling to surface and groundwater. The exchange and transfer of nutrients in the solid and liquid phase and at their interface are studied from the molecular scale to the field scale using state-of-the-art physico-chemical and analytical methods such as NMR, field flow fractionation (AF4, SPLITT), microscopy (SEM/TEM, fluorescence), and scattering (light, X-ray). This research is supported by process-oriented modelling and enables us to elucidate biogeochemical processes in the fluxes and cycling of essential elements, especially nutrients.