The Finnish Environment Institute Syke says that in early January, it received several notifications of blue-green colored ice and algae in the cold waters and ice flows of the Gulf of Finland.
Officials used water and ice samples to confirm that Aphanizomenon algae was the source of a blue-green tint in ice at Pernajanlahti in the eastern Uusimaa region of Finland.
Usually blue-green algae is sighted in July-August when sea water is warm. That’s also when the poisonous Nodularia spumigena blue-green algae is more common.
Though it is not as common, blue-green algae can also form mass deposits in cool water and even under ice.
Aphanizomenon algae is not known to form poisonous blooms in the Baltic Sea. But poisonous strains have been known to infest lakes.
The National Institute for Health and Welfare THL recommends always exercising caution regarding water that contains blue-green algae as it may pose health risks.