In WP2, we integrate and apply state-of-the-art models to simulate POC cycling in coastal and shelf seas. Two different but complementary model approaches, namely forward modeling and inverse modeling, are applied. Inverse modeling is used to reconstruct historical development of deposition, dissolution and sequestration rates of POC in the sediment over several centuries at representative locations such as depocenters. Forward modeling applies 3-dimensional, coupled physical-biogeochemical models to resolve a more complete cycle of POC, including the sources and sinks in both the benthic and pelagic compartments and across the air/sea, land/sea interfaces and the shelf edge. In particular, human pressures (e.g. bottom trawling, sediment dredging and dumping) on benthic biota, sediment resuspension and related POC turnover processes will be explicitly taken into account in the model.