The new and alarming survey of the badly polluted Baltic has been made by the Swedish weather and fishing authorities - who conclude that the growing area where there is no oxygen on the sea bottom now covers an area as big as Denmark and the southern Swedish province of Skåne combined. In this sea virtually no fish or other sea life can live.
Experts have long called for emergency measures to save the Baltic, and there were hopes that Swedish international development assistance to cities in Russia, Poland and the Baltic republics would help stop the flow of untreated urban sewage into the sea.
Speaking with Swedish Television News, Swedish oceanographer Lars Anderson says the situation looks very bad. He says that this is the result of a lack of fresh salt water flowing into the Baltic through the narrow sound when storm winds whip up the waters - and because of the growing population in both the East and West.
Modern agriculture demands mountains of chemical fertilizers and this seeps through the ground water and causes more pollution. In the hot summer months, this feeds the explosion of poisonous, blue-green algae floating on the surface and washing up on the shores of the Baltic. It also sucks up badly-needed oxygen.
During the autumn, scientists on the research ship "Argo" measured oxygen levels from the Finnish Åland islands in the central Baltic and farther south.
Professor Alf Norkko of the Institute of Marine Ecology at the Sweden's Gothenburg University says when the sea bottom dies and life disappears, this releases even more nutrients into the water - reinforcing the negative cycle.
But he adds that some help is coming from nature itself. The tiny bristle worm is spreading on the Baltic sea bottom - apparently able to survive even with the low oxygen levels where other worms die out.
With thousands of worms per square meter, they dig into the mud, binding three times as much phosphorous and other chemicals – just as earthworms digging into your garden aerate the soil, increasing the oxygen levels and making survival that much easier for other living creatures.