Blue-Green Algae Observations Increase Across Finland but Remain Below Seasonal Average
The number of blue-green algae observations in Finland’s inland waters and coastal areas has risen over the past week, though the situation remains calmer than usual for this time of year, according to the Licensing and Supervision Authority.
Nationwide monitoring recorded 203 observations in inland waters, with significant amounts detected in Rokuanjärvi (Vaala), Savijärvi (Sipoo), Kirkkojärvi (Naantali), and Haapajärvi (Lappeenranta). While no extremely abundant blooms were reported, minor blue-green algae was observed at 22 monitoring sites, extending as far north as southern Lapland (Yle).
In coastal areas, 55 observations were made, marking the highest weekly total of the summer so far. Notable concentrations were found off Kotka (Gulf of Finland), Genböle beach (Kemiönsaari), Kärmäläiset (Naantali), and Hökberg (Parainen). Minor blooms were also reported at ten sites across the Gulf of Finland, Archipelago Sea, and Bothnian Sea (Ilta-Sanomat). Despite the increase, coastal observations remain below typical seasonal levels.
Weather Conditions Influence Algae Growth
Recent warm weather and early July rainfall have accelerated blue-green algae growth, though intermittent strong winds may have disrupted the formation of surface rafts by keeping algae mixed within the water column (MTV Uutiset). Satellite monitoring has been hampered by cloudy conditions, but available data suggests an increase in the Bothnian Sea (Yle).
The Finnish Environment Institute’s Tarkka service uses blue-green algae barometers to track open sea conditions, comparing current trends with previous years. Monitoring at approximately 300 sites will continue until the end of September (Yle).
Health and Economic Impacts
Blue-green algae typically appears as green, blue-green, or yellowish particles and can form visible rafts near shorelines. Exposure may cause stomach issues, skin irritation, or flu-like symptoms (Ilta-Sanomat).
Beyond health concerns, the presence of algae may also affect property markets. MTV Uutiset reports that even high-quality lakeside cottages can see reduced buyer interest due to blue-green algae, potentially lowering prices.
