Warm weather spurs increase in blue-green algae blooms in Finland

The recent warm weather has led to a significant rise in blue-green algae (cyanobacteria) sightings in Finland's inland waters, coastal areas, and the Gulf of Finland. According to the latest observations, blue-green algae are appearing more frequently than average for this time of year.

In inland waters, the number of algae sightings has increased since last week.

In Southern, Eastern, and Western Finland, seven national monitoring sites have reported abundant blue-green algae. Additionally, 34 sites in Southern and Central Finland have reported minor algae presence. Although the warm weather has fueled the growth, the anticipated unsettled weather this weekend is expected to curb the proliferation and reduce the formation of blooms.

Coastal areas have also seen a higher than usual presence of blue-green algae. Observations from 21 national monitoring sites indicate significant algae blooms at two sites and minor presence at 19 sites, primarily along the coasts of Southeastern, Southern, and Southwestern Finland.

Satellite monitoring has been particularly effective this week due to clear skies, revealing algae blooms in the Gulf of Finland and dispersed in the northern parts of the Baltic Sea. Earlier this week, surface-level algae were also spotted in the Archipelago Sea, though none were detected in the Bothnian Sea. Satellite images from Tuesday show algae stretching across the Gulf of Finland from Kotka to Helsinki and into the southern parts of the Archipelago Sea, with significant concentrations in the eastern Gulf.

In addition to official monitoring, citizen reports have been crucial. Platforms like Järvi-meriwiki and Vesi.fi have seen a surge in public sightings, with around 300 observations submitted this week alone.

Monitoring and Health Risks

The Finnish Environment Institute (Syke) collaborates with various regional bodies and local authorities to monitor blue-green algae as part of a national environmental program. With over 400 monitoring sites, the program aims to provide a comprehensive overview of algae conditions across inland waters, coastal areas, and the archipelago.

Health risks associated with blue-green algae are significant. According to the Finnish Institute for Health and Welfare (THL), algae can produce liver and neurotoxins, among other harmful compounds. Symptoms from exposure can include skin irritation and gastrointestinal issues. Small children and pets are particularly vulnerable and should be kept away from affected waters. Contaminated water should not be used for bathing, washing, or watering plants.

Local health authorities oversee the algae conditions at swimming areas and provide updates on safety. For the most accurate and timely information, residents and visitors are encouraged to report sightings and check updates through platforms like Järvi-meriwiki.

Recognizing Blue-Green Algae

Blue-green algae can appear as green or yellowish particles in water, forming streaks along shores. In calm conditions, they can create dense, greenish blooms on the water surface. Differentiating between algae and pollen is essential; pollen tends to float on the water surface and settle on objects like docks and outdoor furniture.

If you suspect blue-green algae in water, use a stick to test it: algae will disperse into tiny particles, while other substances may cling to the stick. In a water container, blue-green algae will rise to the surface within an hour as green specks.

For more detailed information and to report sightings, visit the THL, Myrkytystietokeskus, and Terveyskirjasto websites.

HT