REVERSAL OF THE EUTROPHICATION OF THE BALTIC SEA
Phosphorus and nitrogen mass balances for the Baltic Sea are presented (mainly based on data from Larsson et al. 1985) for three situations: 1) present situation, 2) after 80 % P and N removal from point sources, 3) in natural conditions. The balances indicate that a phosphorus removal from point sources will lead to a large reduction in total P loading, in P content of Baltic Sea water and in its phytoplankton biomass, but it will not lead to natural conditions in the Baltic Sea.
Nitrogen removal from point sources is not expected to lead to a significant general change in the trophic level of the open Baltic Sea because of the large diffuse nitrogen sources and because of the internal processes counteracting changes in the external loading. These processes (primarily denitrification) are of special importance owing to the large water residence time (23 years). “Complete abstract not presented.”