Blooms of toxic blue-green algae have drifted to the eastern shores of the Gulf of Finland. The situation is most serious east of Kotka. Health officials have posted warning signs at several beaches.
Individual patches of blue-green algae were visible along the shores, all the way to Hanko. No surface blooms were seen on the open sea on Thursday, but experts say that extensive rafts of the algae could form there if the weather remains calm and warm.
The research vesselMuikku was sent to the open sea to examine the situation. Experts on board said that although large rafts had not formed on the surface, there is plenty of blue-green algae mixed in the water.
"The warm surface layer of the water is nearly 20 metres deep in the open sea, and there is blue-green algae throughout that depth", says Limnologist Seppo Knuuttila on the Muikku.
Finns spending their holidays at their lakeside summer cottages have not yet faced the toxic algae problem in many places.
Very large amounts of it have only been found in Lake Mainiojärvi in Somero and the Ruskonjoki river in the Turku region. Large amounts have been found in nine other lakes in different parts of Finland.
"Last summer the amounts of blue-green algae in lakes peaked in early September after a warm August", says researcher Sari Mitikka of the Finnish Environment Institute.
