Blue-green algae affecting some beaches

The long spell of hot and calm weather has increased the occurrence of blue-green algae both in coastal waters and inland lakes. The continuing hot conditions are likely to add to the algal growth to the extent that it will start causing problems to swimmers. Many bathing beaches are already posting notices warning of the algae.
      On Tuesday, plenty of blue-green algae were visible for example on the Laajasalo beach in Helsinki, where swimmers were made aware of the presence of the hazard. Smaller amounts were detected on a few other beaches in the capital area. Then again, there were many beaches that were totally free from algae.
      "Warning signs are posted even for the smallest amounts of blue-green algae", explains senior health inspector Leea Kultanen from the City of Helsinki Environment Centre.
      "Swim bans, however, are rarely imposed, as the situation on beaches may change within hours, depending on the prevailing winds."
     
On Tuesday, biologist Mikaela Ahlman from the Uusimaa Regional Environment Centre was collecting samples near Pellinki in the Porvoo archipelago.
      "It seems that the blue-green algae are now surfacing in the coastal waters. It is dead calm here, and the thick streaks of algae are clearly visible on the surface", Ahlman explained.
      The sea waters have been exceptionally clear this summer. This is because of lack of rain, which has resulted in low effluent runoff into the sea.
     
"The prevailing winds and currents have taken the warm water out into the open sea, from where cooler water has come in its place into the coastal region. As the blue-green algae do not thrive in cold conditions, their blooming has so far been only moderate", says special researcher Pirjo Kuuppo of the Finnish Environment Institute.
      "Now the situation may be changing. In August we may still see extensive algal blooms", Kuppo reckons.
     
In the western city of Naantali, many of the city's public beaches carried signs warning of the blue-green algae.
      In the past few days, visual inspections had detected some algae, and the officials thought it appropriate to warn the public well in advance.


Previously in HS International Edition:
  Blue-green algae hits shores in east of Gulf of Finland (6.8.2004)
  Experts fear bad blue-green algae situation in Gulf of Finland this summer (10.5.2004)

Links:
  City of Helsinki Environment Centre: Algae situation on public beaches
  Finnish Environment Institute Press Release