Blue-green algae are spreading in the Baltic Sea and lakes in M-V and Schleswig-Holstein

Rostock/Lübeck. Blue-green algae have spread on the Baltic Sea and on many lakes in Mecklenburg-Western Pomerania and Schleswig-Holstein. Satellite images from the Federal Maritime and Hydrographic Agency show large carpets of algae off the coast between Rostock and Hiddensee. These stretch across the entire inland sea up to the Danish coast.

The Ministry of Health in Schwerin therefore advises bathers to avoid areas with visible algae accumulations. The algae bloom can be recognized by a bluish-green cloudiness of the water, streaks, carpets of algae on the surface or cloud-like distributions in the water. Accumulations depend on wind and weather and can change within a few hours.

On the Baltic Sea, the coasts near Rostock-Warnemünde, Kühlungsborn, Heiligendamm and the Wohlenberger Wiek near Wismar are among those affected. Rivers and lakes such as the Peenestrom, the Schwandter See and the Melzer See (both in the Mecklenburg Lake District) are also affected. However, there are no bathing bans due to blue-green algae.

In Schleswig-Holstein, bathing bans were imposed in some lakes due to blue-green algae. Lake Bordesholmer, Brahmsee, Warder See and Dörpsee are affected. All are in the Rendsburg-Eckernförde district. According to the country, the bans are expected to last until Wednesday.

There are also swimming warnings for several bathing areas on the Baltic Sea in the Ostholstein district, for example on the coast in front of Sierksdorf, Rettin or Scharbeutz. According to the state, people should avoid swimming and bathing if bathers can no longer see their feet in the water above knee height because of the bluish-greenish turbidity. In these cases, even small children should no longer play on the bank or splash around in shallow water.

Summer weather offers ideal conditions for blue-green algae. Contrary to its name, it is not classic algae, but so-called cyanobacteria, said the city of Rostock. Individual cyanobacteria cannot be seen with the naked eye, but if they occur in large numbers they can become visible, for example as streaks or discoloration in the water.

The State Office for Health and Social Affairs (Lagus) in Mecklenburg-Western Pomerania points out that cyanobacteria can produce toxins. This could cause allergic reactions, irritation of the skin and mucous membranes if touched, and possibly nausea and vomiting if large amounts of water are swallowed.