Researcher Sirpa Lehtinen from the Finnish Environment Institute (Syke) said that cyanobacteria exist in seawater all year round, but intense heat causes them to multiply quickly.

With current tropical conditions set to continue for another week, the situation is not likely to improve before the end of July or early August.

The Finnish Environment Institute (SYKE) has warned that the Gulf of Finland faces the risk of earlier and larger than usual blue-green algae blooms this summer – weather permitting. The environment agency says high levels of phosphorous have the potential to feed abundant toxic algal growths.

The scientist noted that the amount of phosphorus, which is essential for cyanobacterial growth, in the Gulf has dropped by around 60 percent compared to their worst, peak levels.