The environmental status of the Baltic Sea in the 1940s, today, and in thefuture

In the 1940s, the Baltic Sea was a nutrient-poor sea with low biological pr oduction, clear water, and rocky shores with dense growths of the brown sea weed bladderwrack, providing food and shelter for many species, including s pawning and nursery grounds for many fish. There was sufficient oxygen in t he bottom water for cod to spawn in the deep areas of the Baltic Proper, ex cept for periods of oxygen depletion in the Gotland Deep. Top consumers lik e seal and sea eagle were common and people living around the Baltic Sea co uld eat fish without risking their health. The Baltic Sea of today is diffe rent. Eutrophication and toxic substances now affect the entire Baltic Sea ecosystem, even the offshore areas. Filamentous green and brown algae shade the bladderwrack and may even totally replace it. Increased plankton bloom s and organic particle production has lowered light penetration by 3 m and oxygen depletion and hydrogen sulfide formation sometimes dominate as much as one third of the total bottom area. Seals and sea eagles are slowly reco vering emissions of PCB and DDT from the effects of the large during the 19 60s and 1970s. To reduce the nutrient load to the levels of the 1940s, a re duction by 65% for phosphorus and 80% for nitrogen is needed. Furthermore, society's massive processing of potentially hazardous chemicals must be sub stantially reduced, and preferably stopped entirely. We now have adequate k nowledge of how the Baltic Sea ecosystem functions, and of what is needed t o restore the Baltic environment. This requires large societal changes espe cially in agriculture, transportation, and industry. The successful elimina tion of PCB and DDT emissions shows that even large-scale, negative trends can be reversed. Here, an efficient and technologically advanced industry h as an important role to play. But success will be delayed, as long as polit ical issues are given higher priority than environmental action.