Despite the high temperatures seen last month, the situation of toxic blue-green algae blooms in the Gulf of Finland has been relatively reasonable this summer, according to Seppo Knuuttila, a senior research scientist from the Finnish Environment Institute (Syke).
"It has been very interesting to observe the situation this summer. As a researcher, I'm interested in seeing how our algae risk forecast will play out," he said.
Blooms in water of blue-green algae — also known as cyanobacteria — can be harmful to people and animals.
Warm temperatures are a contributing factor to the toxic blooms, and there has not been a shortage of those, as it was relatively hot most of the past two months. Some areas of the country experienced the hottest summer in a century in June and July.
Another factor that encourages blooms is high nutrient levels — often increased by runoff from agriculture. At the beginning of last month Syke issued a warning of the risk of significant algae blooms in the Gulf, but the opposite appears to have happened.
Knuuttila and his colleagues have found that blue-green algae levels this summer were at their lowest since the beginning of this century. However, there was an uptick of algae in the Gulf of Bothnia, the researcher noted.
Reasons still unknown
Knuutila said that it remained unclear exactly why the blooms did not arrive as predicted but added that more detailed analysis would be carried out.
"I have observed that the reduction in the nutrient load in the Gulf has started to have an effect," he said, adding 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.
"This summer gives us hope," he said.
However, a new extensive heatwave later on this summer could worsen the situation.
According to Syke, children and pets must not be allowed into contaminated water, and adults should also avoid swimming. The institute has advised that children or pets suspected of having been exposed to contaminated water should be thoroughly washed with clean water.
Water containing blue-green algae must also not be consumed by people or animals, even after boiling.