Lakes less affected by algae than rivers

Cyanobacteria are abundant in particular in the Finnish southwestern open sea areas of the Baltic Sea, said a press release of The Finnish Environment Institute (SYKE).

In lakes, less cyanobacteria have been observed than generally found at the end of July.

Spores of rust fungi that form coloured surface occurrences have been reported this week particularly in lakes in Southwestern Finland.

The arrival of the dreaded blue-green algae on Finnish shores was delayed due to cold summer but a slight warming this week coincided with sightings of algae in south-west waters, reported National broadcaster Yle.

The SYKE said that blue-green algae, which can cause an upset stomach or worse on contact with swimmers, is present on Finnish beaches once again this summer.

"Blue-green algae is visible in Finnish waters across almost the whole of the western Gulf of Finland, the southern Archipelago Sea and the northern reaches of the Baltic Sea," said researcher Sirpa Lehtinen of the SYKE in the press release.