Heavy summer blue-green algae growth expected in Gulf of Finland

Less phosphorous in water than last year

print this

If the upcoming summer is warm and sunny, toxic blue-green algae is likely to appear on the surface of the Gulf of Finland and the southern parts of the western archipelago.
      Researchers of the Finnish Environment Institute (SYKE) and the Finnish Institute of Marine Research predict a high risk of blue-green algae in maritime areas near the southern part of Finland.
      However, SYKE researcher Heikki Pitkänen says that the risk this year is not as great as last summer, when there was a record amount of phosphorous in the sea.
      This year, the phosphorous content of the sea water is about 25% lower than it was in 2004.
     
The heaviest blooms of blue-green algae are expected in the southern parts of the Baltic Sea, where the nutrient level in the water is especially high.
      Heavy storms in the winter stirred up the water in the main basin of the Baltic, releasing nutrients at the bottom into the surface layers of the sea, which now contain exceptionally high levels of phosphorous.
      The extent of the blue-green algae problem will depend largely on the weather. Warm and sunny conditions favour the growth of the algae. If conditions remain cold and windy, most of the algae will remain mixed in the water, reducing the amount of large blooms on the surface.
     
The intensity of the blue-green algae problem is the result of the increase in the so-called internal load in the sea, which has been growing since the early 1990s.
      The sea tends to feed itself: as oxygen is depleted, nutrients on the bottom rise to the surface, resulting in an accelerated level of eutrophication.
      "The situation would improve if the mass of water could be efficiently mixed each year, giving the bottom layers a boost of oxygen", Pitkänen says. The last time that this occurred was in the early 1990s.


Links:
  Finnish Institute of Marine Research Baltic Sea Portal: Algae information

Helsingin Sanomat