Itämeren ja Mustameren geologinen historia, sedimentaation kehitys sekä ympäristöongelmien vertailu

The study area includes the Baltic and the Black Sea and their catchment basins based on mainly recent literature. The purpose of this study is to clarify environmental problems of these seas and the effect of geologic history and other factors of basins. The early geologic history of the Baltic Sea and the Black Sea basins differ from each other. The Baltic Sea basin (~2,5 Ga BP) is clearly older than the Black Sea basin (~299 Ma BP) and formation processes of these two basins are not related to each other directly. The Quaternary glaciations were intensive in the whole Baltic basin, whereas in the Black Sea only the highest and some northernmost areas of the basin were covered by ice sheet. The last connection between sea and these two basins have occurred almost at the same time, which is in the Baltic Sea ~8,5–6,5 ka BP and in the Black Sea ~9,4–8,4 ka BP. The most significant environmental problems in the Baltic and Black Sea are eutrophication, overfishing, non-indigenous species, heavy metals and hazardous substances. In general anthropogenic forcing is greater in the Baltic Sea than in the Black Sea leading changes in an ecosystem. The inflow of nutrients and pollutions occurs especially in to the northwest region of the Black Sea where large rivers (Danube and Dnieper) flows. On the contrary the eutrophication is wide and occurs almost in the whole basin of the Baltic Sea. It may take decades before the effect of reduced nutrients and the recovery of marine ecosystem occur in the basin. There are no significant heavy metals or hazardous substances contamination observed in the both sea basins. The results indicate that the overfishing and the spreading of non-indigenous species have caused more damages in the Black Sea than in the Baltic Sea. There have formed several environmental conventions both in the Baltic Sea and in the Black Sea which are emphasized especially in the Baltic Sea because of actions of EU. The effect of EU will probably increase in the Black Sea in future because new member countries such as Bulgaria and Romania and candidate country Turkey are surrounding by the Black Sea.