Origin and transport of terrestrial organic matter from the Oder lagoon to the Arkona Basin, Southern Baltic Sea

We investigated the origin and the transport of terrestrial organic matter from the River Oder to sediments in the Pomeranian Bight (Southern Baltic Sea) by using lignin as a molecular tracer. Approximately 40% of the organic carbon in Pomeranian Bight sediments are land-derived and the contribution of Oder lagoon organic carbon does not decrease significantly with increasing distance to land. Most of the lignin (>60%) originates from non-woody angiosperm tissue and can be attributed to river discharge. In the Arkona Basin, the contribution of non-woody angiosperm tissue is higher than at the other stations and suggests that the basin may receive additional lignin from another source in the North. Alternatively, the shift in lignin composition may be due to hydrodynamic sorting. Peat-like material, which was also sampled, consists of highly oxidized gymnosperm wood and indicates that eroded strata at the seafloor do not contribute significantly to bulk lignin in the sediment. The Oder flood in July 1997 had no significant effect on the amount and composition of terrestrial organic matter in the Pomeranian Bight.