Massive sedimentation of fine sediment with organic matter and enhanced benthic-pelagic coupling by an artificial dyke in semi-enclosed Chonsu Bay, Korea

► We assess the impact of an artificial dyke on the organic carbon cycle. ► Massive organic matter is deposited near dyke by change of tidal circulation. ► Organic C oxidation rate in sediment near dyke was two times higher than out of bay. ► The nutrient benthic fluxes were four to six times higher than those outside bay.