TRUMP: Structure and function of the Pomeranian Bight - nutrient transport, retention and budgets
Modification and fate of Odra-derived material in the coastal area of the Pomeranian Bight were studied in the frame of this interdisciplinary project.
During the biological growth season the nutrient load of the Odra is funneled into the strongly regenerative cycle of matter of the coastal system. In this situation, a stable balance between auto- and heterotrophic processes develops along the mixing gradient with a concurrent dilution of biomass. The absence of a stable vertical stratification promotes intensive bentho-pelagic coupling. The benthic biomass is dependent on pelagic input. Comparisons of recent macrozoobenthos abundance patterns with a study in the late 50ies showed a biomass increase of suspension feeding bivalves by the factor of 8 over those four decades. In spite of this enormous increase in biomass, the macrobenthos provides only a limited buffer function for imported substances. The Pomeranian Bight is judged to represent rather a transit- than an accumulation-area for organic carbon and associated elements including organic pollutants.
During winter time relatively high concentrations of phosphorus and nitrogen pass the coastal system unmodified and are diluted into the open Baltic surface waters. Transport speed and -direction of dissolved and particulate material are dependent on the wind conditions. The main export areas of material from the bight are the Gdansk Bay, the Arkona Sea and the Bornholm Sea according to the prevailing wind directions.
A major achievment was the integration of huge amounts of disciplinary data in a coupled circulation-ecological model. The modelling concept, that was developed within this project, was proven in the assessment of the effects of the Odra flood under extreme runoff conditions.
Institut für Ostseeforschung Warnemünde