Sediment mixing processes and accumulation patterns in the south western Baltic Sea Anthropogener Einfluss Bioturbation Cäsium 137 Geochemie Ostsee Quecksilber Radiographie Resuspension Sedimentologie Coastal and marginal seas – like the Baltic Sea – serve as natural reaction sites for the turnover and accumulation of land derived inputs. The main location for the modification and deposition of the introduced material is in most cases not the water mass but the sediment. Its key function as central reactor in the interaction between land and sea has so far been insufficiently studied and assessed. This study was part of the interdisciplinary SECOS project that aimed to identify and evaluate the service functions of sediments in German coastal seas in the context of human use with a focus on the Baltic Sea. One of its goals was to assess sediment functions related to the intermediate storage or final sink of imported material like nutrients and contaminants and quantify their inventory as well as their mass accumulation rates on multi decadal to multi centennial time scales. For that a detailed examination of the natural and anthropogenic processes that interfere with sediment accumulation in the south western Baltic Sea basins is essential.