Baltic Earth Working Group on Land-Sea biogeochemical linkages in the Baltic Sea region

This topic involves the problems of euthrophication and acidification. A lot of experimental data and sophisticated model tools are available but there is a lack of process understanding, and proper process parametrizations are missing. The processes occurring within the drainage area greatly influence the functioning of the Baltic Sea ecosystem. First of all, river runoff affects the Baltic Sea salinity, which is the key element for the marine biogeochemistry in general. Moreover, rivers supply the Baltic with great loads of different chemical substances. In most cases (e.g. nutrients, carbon, alkalinity, some organic pollutants and heavy metals), these loads are well recognized. However, some gaps still exist within the present databases. One example is missing data from the Neva River, incidentally the largest river entering the Baltic Sea. For some other chemical substances (e.g. pharmaceuticals) the terrestrial loads are still insufficiently described. On the other hand, the pathways of several substances, after entering the marine system remain unrecognized. Still, little is known about the transformation mechanisms occurring within the mixing zone. Since the geological structures, anthropogenic influences, types of the vegetation are different in the different parts of the catchment, the detailed studies are required for the individual subbasins. Key suggested research areas are C, N, P cycles studies for the understanding primary production mechanism and organic matter transformations in the Baltic Sea, transformations and pathways of terrestrial organic matter, influence of the terrestrial input on the carbonate system, extension of the databases with the missing terrestrial loads data of the key chemical substances (e.g. Neva River).

Potential activities include the development of land-ocean system models. Suggested key research areas in this field are investigations on the carbon, nitrogen and phosphorus cycles towards an understanding of primary production mechanisms and organic matter transformations in the Baltic Sea, transformations and pathways of terrestrial organic matter, and the influence of the terrestrial input on the carbonate system. Furthermore, the extension of databases with missing terrestrial loads data of the key chemical substances (e.g. from Neva River) should be pursued. Review papers and dedicated workshops will provide a platform to discuss the scientific results.

Baltic Earth Workshop on “Challenges for biogeochemistry research in the Baltic Sea Region”, Institute of Oceanology Polish Academy of Sciences (IO PAN), Sopot, Poland, 13 November 2013