Surface waters are now largely warmer than average in Finland, according to observations collected by the Finnish Environment Institute.
On Thursday, the surface water at the observation stations in Southern and Western Finland was between 18 and 22 degrees.
In central and eastern Finland, Kainuu and southern Lapland, surface water temperatures rose to a maximum of 20 degrees, while in northern Lapland temperatures varied between 12 and 16 degrees.
Water temperatures are widely two to six degrees higher than the seasonal average.
In Härjärvi, Närpiö, Ostrobothnia, 22-degree surface water was about six degrees warmer than usual at this time of year.
In the northernmost part of Finland, the surface water temperature in Kevojärvi, Utsjoki, was about 12 degrees, which is also almost five degrees higher than the average in June.
The occurrence of cyanobacteria cannot be predicted from an increase in temperature
Heidi Hällfors, a researcher at the Finnish Environment Institute, says that the warm surface layer of water is relatively thin and cooler water mixes easily with it.
As a result, the blue-green algae situation of Midsummer, among other things, cannot yet be predicted from rising temperatures.
He says the blue-green algae situation is normal and calm compared to the season.
Blue-green algae observations have been made to some extent along the coast.
The water is currently colored the most by pine pollen, which resembles cyanobacteria in appearance.
The appearance of cyanobacteria is influenced by, among other things, weather conditions.
- Blue-green algae thrive in the same conditions as holidaymakers, ie in calm, sunny and warm weather, Hällfors says.
Cooler and windier weather reduces the conditions for the growth of cyanobacteria, but the cyanobacteria already formed does not immediately disappear but mixes deeper into the water.
Blue-green algae water should not be used even for irrigation of vegetable land
Hällfors suggests that there are two ways to identify cyanobacteria: a glass test and a stick test.
In the stick test, the stick is immersed in colored water.
If something is left hanging on a stick, it’s not blue-green algae.
Blue-green algae decomposes into a benefit in a stick test.
In the glass test, place turbid water in a clear glass vessel and allow to stand for one hour.
Blue-green algae rise to the surface of the water, while the rest sinks to the bottom of the glass.
According to Hällfors, the problem is that pollen behaves in the same way in both tests.
As a general rule of thumb for separating pollen and cyanobacteria, there is a time.
A definite distinction cannot be made, but pollen often stains the waters from early summer, whereas cyanobacteria basically occur in July-August.
- Whenever you see water discoloration, you should be treated with healthy suspicion and caution, Hällfors reminds.
Going into blue-green algae should be avoided, and especially children and pets should be kept out of the water.
Blue-green algae water must also not be used to irrigate the vegetable garden, to fill the steam shaft or for household needs.
- Dogs may receive a lethal dose of poison from licking their fur after swimming, Hällfors says.
If cyanobacterial water enters the mouth or other symptoms of water occur, contact a health or poison control center.