Blue-green algae rises in seas, reduces in lakes

The blue-green algae situation has remained stable in inland waters, and slightly less blue-green algae than in previous monitoring years have been observed, said Finnish Environment Institute (SYKE) in a press release on Thursday.

Blue-green algae observations have increased on the coasts, and plenty of observations have also been made in the Bothnian Sea and the Åland Sea.

The amount of blue-green algae blooms in the Åland Sea has been significantly lower in early summer than at the same time in 2023, and the amount of blooms has reached the 2023 level only after mid-July.

In the Bothnian Sea, blue-green algae bloom situation in early summer was similar to that in 2023, but this week the amount of blue-green algae blooms will exceed both the previous year and the range of 2009–2023.

SYKE observes the cyanobacteria occurrence as part of the monitoring of the state of the environment in Finland

The national cyanobacterial monitoring is carried out as part of the monitoring of the state of the environment in cooperation with the Centres for Economic Development, Transport and the Environment, municipal environmental and health authorities, and the SYKE. Finnish Rotary Clubs are also actively involved in nationwide cyanobacterial monitoring.

The cyanobacterial monitoring is based on the monitoring of cyanobacterial deposits in surface water.

The intention is to provide an overview of the cyanobacterial situation in different water bodies.

The monitoring includes about 400 permanent observation sites across the country on inland and coastal waters and in the archipelago.

Information on the cyanobacterial situation in the open sea areas is mainly obtained from satellite images, but also from the Finnish Border Guard, the marine research vessel Aranda, the optical device located at the Utö Atmospheric and Marine Research Station, as well as cruise and merchant ships (MS Finnmaid and MS Silja Serenade). The drift forecasts for cyanobacterial rafts in open sea areas are prepared in cooperation with the Finnish Meteorological Institute's Maritime Services.

SYKE reports on the national cyanobacterial situation on a weekly basis every Thursday from June 20 to August 8 August 2024. The weekly algal reporting was launched in 1998.