The blue-green algae situation can change quickly in the summer

Summer water is enticing to swim, but the beach water seems to be greening. Do you dare to go swimming? Check the blue-green algae situation before swimming!

On this page you will find the latest algae-related news published by the Finnish Environment Institute (SYKE), and up-to-date information on the Baltic Sea’s algae situation during the summer months.

In this context, the word algae refers to microscopic phytoplankton algae, which include all blue-green algae (cyanobacteria). Algal bloom observations refer to algal blooms visible to the human eye or in satellite images.

The algal bloom monitoring information is based on satellite images and observations reported on the JärviMeriWiki website.The algal bloom map also includes the latest observations from the beaches that are supervised by the City of Helsinki.

More information on the algae situation at the beaches of Finnish municipalities can be found on each municipality’s website.

JärviMeriwiki (in Finnish, data updated only during the summer)   

Outdoor exercise map (data updated only during the summer)  

Identifying and reporting cyanobacteria findings

Blue-green algae often appear as greenish or yellowish particles in surface water. However, it should not be confused with pollen, which also forms rafts on the surface of the water, especially in spring and early summer. The number of cyanobacteria, on the other hand, increases in late summer when the waters have warmed

Here are instructions for identifying cyanobacteria in Finnish JärviMeriwiki: miten tunnistan sinilevän

Reporting cyanobacterial findings is important. Collected data can be used to monitor eutrophication on marine areas.. Report your algae observation! (in Finnish) 

Algae-produced toxins

Large algal blooms should always be treated with the expectation that they are harmful to humans and animals. In addition to harmful toxins, other health-threatening substances can be present in water that has large amounts of algae.

The Poison Information Center answers questions concerning the prevention and treatment of acute poisonings every day, around the clock . Contact the center by calling +358 800 147 111. The call is free of charge.