Some ecological properties in relation to eutrophication in the Baltic Sea

The current published information of the influence of eutrophication on the Baltic Sea is reviewed and summarized. Harmful effects at different levels of the ecosystem are identified, and the spatial and temporal variability of these properties characterized. The Baltic Marine Environment Bibliography was searched on the web, and some 1170 references with eutrophication as a keyword were extracted and analyzed. The most studied regions were the Gulf of Finland (including the Archipelago Sea), Kattegat and the Bothnian Sea. The search was further divided into several parameters (transparency, oxygen/hypoxia, nutrients, primary production/ chlorophyll a, algal mats, macroalgae, zoobenthos and fish) related to eutrophication. In most regions, chlorophyll, zoobenthos and fish were the most commonly studied biological and ecological parameters. The linking of eutrophication, ecology and a potential decision-support system is discussed, and related to similar attempts elsewhere.