Marine surface sediments act as a dynamic interface between oceans and geological reservoirs. They are inhabited by a rich microbial ecosystem regulating the exchange of matter across the seabed. Biogeochemical cycles in the ocean, the composition of seawater and the formation of seabed resources are strongly affected by the fluxes between surface sediments, the overlying water masses and the underlying geological reservoirs. Understanding the mechanisms and feedbacks that are controlling these fluxes is the major challenge for research unit Marine Geosystems.

The research unit develops and applies advanced technologies to determine the fluxes across the seabed and the biogeochemical turnover in marine sediments. These include lander systems for in-situ flux measurements, microbial rate measurements, molecular studies and numerical modeling to predict benthic turnover under dynamic boundary conditions. New elemental and isotopic proxies are applied to better understand mineralization processes and geochemical sediment-water interactions. Isotopic techniques and numerical modeling are also used to reconstruct and understand biogeochemical cycling and the evolution of seawater composition on geological timescales.

Sub-seabed geological reservoirs are increasingly explored and exploited to meet the ever growing demand for energy and mineral resources and waste-disposal capacities. The research unit Marine Geosystems is developing cutting-edge monitoring techniques and novel approaches for resource utilization to mitigate and minimize the detrimental effects of these industrial activities on the marine environment.