This summer may see unprecedented levels of blue-green algae, or cyanobacteria, in Finnish waters, according to forecasts by the Finnish Environment Institute, Syke.
The prediction is based on the fact that scientists have recorded high concentrations of residual phosphorus in the waters. Phosphorus is a nutrient that is particularly important in fuelling cyanobacteria growth.
Furthermore, warm waters cause blue-green algae to rapidly bloom en masse, and this week Finland is set for heatwave conditions that will also likely result in warmer water temperatures.
Hermanni Kaartokallio, a senior researcher at Syke, says that the peak time for algae-infested waters is not usually until late summer, after mid-July.
Cyanobacteria monitoring sites are yet to show any worrying signs, Kaartokallio adds. Only three sites in southern Finland, Lohjanjärvi, Usminjärvi in Kytäjoki and Haapajärvi in Nuijamaa, have so far recorded some presence of blue-green algae.
"The blue-green algae situation has remained calm in sea areas and inland waters, as typical in early summer," Syke's website notes, adding that "currently, variable, windy weather and cool water temperatures are keeping blue-green algae under control."
Toxic for humans and animals
Both people and animals – especially small children and dogs – can become very ill from touching, swallowing or even breathing in water droplets containing the toxic algae.
"Toxic water can cause skin symptoms, among other things. I wouldn't let a dog swim in waters that a human wouldn't swim in," Kaartokallio points out.
Water contaminated with blue-green algae must never be thrown onto a sauna stove, either, as exposure through skin and respiration causes even more symptoms than swallowing it.
How to tell if it's blue-green algae?
Seeing little green or yellow specks on the surface is usually the first sign of whether the water is safe enough to swim in.
Often, however, people confuse pollen for blue-green algae. In order to correctly identify cyanobacteria, the Finnish Environment Institute advises using a stick or a glass.
"To tell blue-green algae from other types, you can use a stick: if you can pull up the algae from water with the stick, it is not blue-green algae. Another method is collecting some water into a glass and letting it stand for an hour. Buoyed by their gas vacuoles, blue-green algae rise to the surface," the Institute advises.
Another way is to stay up-to-date with the current blue-algae situation of a given location is through Syke's map service.
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