Ajankohtaisia katsauksia vesitilanteesta
Algae situationBlue-green algae situation in the map service
Sinilevätilannekartta esittää pistemäisinä havaintoina sinilevätilanteen noin 400 havaintopaikalta, joista pääosa on yleisillä uimarannoilla. Tilanne arvioidaan havaintopaikoilla kerran viikossa. Myös kansalaiset voivat ilmoittaa sinilevähavaintoja ja perustaa omia havaintopaikkoja havaintolähetin kautta. Huomaa, että havaintopaikan sinilevätilanne voi muuttua nopeasti esimerkiksi säätilanteen mukaan. Sinilevät voivat tuottaa erilaisia levämyrkkyjä. Sinileväpitoisessa vedessä ei pidä uida eikä päästää siihen myöskään kotieläimiä.
The blue-green algae situation is monitored in summer
The Finnish Environment Institute updates the algae situation every week from the beginning of June until the end of September.
What everyone should know about blue-green algae
Blue-green algae are at their most prolific around midsummer and in late summer. Large masses of blue-green algae in the water are a sign of eutrophication. Blue-green algae blooms hamper recreational use of waters and may produce algal toxins. You need to watch out for blue-green algae, which is why learning to recognise them is a good idea.
Recognising blue-green algae
Blue-green algae are usually only seen in the water as small, greenish specks. You cannot lift them out of the water with the stick as you can with filamentous green algae. A thick gunk of blue-green algae may build up in surface or shoreline waters. A good way of identifying them is letting some water stand in a drinking glass; if the specks rise to the surface within an hour, they are blue-green algae. The timing helps to tell blue-green algae apart from pollen: pollen is found in early summer, whereas blue-green algae typically occur in the middle and at the end of the summer.
Why should I watch out?
Some blue-green algae are toxic, but it is impossible to tell them from the non-toxic species by visual examination, and consequently you should be careful with all blue-green algae. You should never ingest water containing them, or use it in the sauna. You should also avoid bathing in the water and using it for watering any plants that you intend to eat. Do not allow your dog or other pets to drink water with blue-green algae or play around in it. Algal toxins can also make animals sick or even prove fatal to them.
Where and when?
Blue-green algae occur especially in lakes affected by eutrophication. In the Baltic Sea, blue-green algae blooms are commonly seen in the Gulf of Finland and the Archipelago Sea. When the water warms up around midsummer, the algae start proliferating. Large algae masses can appear quickly in July and August, and in calm weather they rise to the surface as algal blooms. Report your blue-green algae observations on vesi.fi map service or Järvi-meriwiki!
Did you know this about blue-green algae?
Blue-green algae are bacteria
Blue-green algae are actually bacteria known as cyanobacteria. Unlike many other types, they photosynthesise in sunlight similarly to algae and plants. The number of different blue-green algae species is vast, and not all of them drift around in water: the slippery fluff appearing along the waterline on a cliff may also be blue-green algae. With a bit of luck, you may see beautiful green globes of blue-green algae at the bottom.
Blue-green algae produce toxins
Blue-green algae may produce hepatotoxins and neurotoxins or other similar harmful compounds. Blue-green algal toxins may cause various generic symptoms, including nausea, fever, flu-like symptoms, redness of eyes or skin symptoms. Different people may have varying levels of sensitivity to these algal toxins. The symptoms of poisoning usually occur within a few hours of exposure. Contact a physician if you suspect that you have symptoms caused by blue-green algae.
Gas bubbles lift algae to the surface
Blue-green algae floating in the water have small gas bladders that buoy them towards the surface. The significance of these gas bladders becomes evident in calm weather conditions when the specks of blue-green algae crowd together on the water surface in a large mass, looking like somebody poured green paint into the water. Wind usually breaks up the algae masses and disperses them in the water, but it may also push them onto the shore.
Mass occurrences can appear rapidly
Blue-green algae rely on cell division as an efficient and fast way of reproduction. In favourable conditions, masses of blue-green algae may appear in just a few days. Factors that promote the appearance of blue-green algae blooms on the surface include a high phosphorus concentration in the water and suitable weather, particularly the temperature and wind conditions. Some blue-green algae also produce spores asexually, helping the species survive over winter or through other periods of less favourable conditions.
Blue-green algae are nitrogen fixers
Blue-green algae are the only photosynthesising organisms that can fix atmospheric nitrogen dissolved in water. Not all species of blue-green algae are able to do this, but some have cells specialising in nitrogen fixation. Fixing nitrogen is a demanding task that requires plenty of energy. This strategy pays off, however, as it gives the blue-green algae floating in the water the upper hand over other planktonic algae if bioavailable nitrogen is in short supply.