The impact of Oder river waters on the ecosystem of Pomeranian Bay

The project was carried out in 1996-1998 and was co-funded by the Foundation for Polish-German Co-operation in Warsaw.

The following scientific institutions took part in the project:

• the Sea Fisheries Institute, Gdynia (SFI) - the co-ordinator of the project,
  
• the Institute of Oceanology of the Polish Academy of Sciences, Sopot (IO PAS),
  
• the Marine Biology Centre of Polish Academy of Sciences, Gdynia (MBC PAS),
  
• the Institute of Oceanography, University of Gdansk, Gdynia (IO UG),
  
• the Academy of Agriculture, Szczecin (AA).
  

The Pomeranian Bay is an element of the River Odra (Oder) estuary. The oceanographic conditions in the estuary are, to a great extent, formed by seasonal variability in the outflow of riverine waters. The Odra is one of the largest rivers discharging its waters and pollutants into the Baltic Sea. The drainage area of the river covers part of the areas of three countries: Poland, Germany and the Czech Republic. Before the Odra waters enter the Pomeranian Bay they flow through the Szczecin Lagoon (Zalew Szczecinski, Oderhaff) and the Swina, Dziwna and Peene (Piana) rivers which together play a significant buffering role. Bereft of topographical barriers, the Pomeranian Bay is exposed to permanent, intensive water exchange between itself and the neighbouring Arkona and Bornholm Basins; the Bay is the scene of intensive mixing of riverine and seawaters.

The main aim of the project was to study the pathways of anthropogenic substances in the Pomeranian Bay and to determine their impact on the Bay's ecosystem.

The work packages in physics, chemistry and biology covered the following aspects of the ecosystem:

• hydrodynamics (IO PAS, SFI),
  
• loads of matter discharged into the Bay by the Odra (SFI),
  
• acoustic properties of the Pomeranian Bay bottom sediments (IO PAS),
  
• nutrients in seawater (SFI),
  
• nutrients in the bottom sediments (IO UG),
  
• structure of the pelagic community and energy/matter flow (SFI),
  
• the part played by bacteria in the pelagic system of the Pomeranian Bay (MBC PAS),
  
• structure and functioning of benthic communities in the Pomeranian Bay (AA, SFI),
  
• heavy metals in the sediment and benthic organisms (IO PAS, SFI),
  
• radioisotopes in the sediment and water of the Pomeranian Bay and Szczecin Lagoon (IO PAS),
  
• pesticides and CBS in water and organisms (SFI).
  

As the Pomeranian Bay straddles the border between Poland and Germany, the two countries worked out a detailed joint programme to fulfil the expectations of both partners and provide good co-ordination of the fieldwork. The project was carried out in close co-operation with the Institute for Baltic Research in Warnemünde.