General: The chlorophyll a concentration in the western and central Gulf of Finland is between 3 and 5 µg/l. The surface temperature in the open Gulf of Finland is around 15 degrees. In coastal areas the water temperature has decreased due to upwelling and is now between 10 and 11 degrees. The surface salinity in the is between 5 and 6 promilles in the Gulf of Finland and the northern Baltic Proper.
Nutrients: The phosphate-phosphorus concentration is still low, being below 0.07 µmol/l in the western Gulf of Finland and the northern Baltic Proper. Although deep water upwelling has brought also phosphate to the surface in coastal areas, the near coast concentration is not above 0.1 µM/l. Nitrate- and nitrite-nitrogen concentrations vary between 0 and 0.3 µmol/l and silicate-silicon concentrations between 4 and 7 µmol/l in the Gulf of Finland and the northern Baltic Proper.
Species composition: Filamentous (Aphanizomenon flos-aquae, Oscillatoriales spp.) and colonial (Chrooccales spp.) blue-green algae are still moderately common in the Gulf of Finland and northern Baltic proper. Some diatoms (Chaetoceros spp.), a few large dinoflagellates (Dinophysis acuminata, D. rotundata) and nanoflagellates (Teleaulax spp., Plagioselmis prolonga, Chrysochromulina spp.) occur also in moderate amounts. The dinoflagellate Prorocentrum minimum is relatively common in the central Baltic proper, while the diatom Skeletonema costatum and nanoflagellates (Chrysochromulina spp., Eutreptiella gymnastica) dominate in the Arkona Sea.
Forecast: The bluegreen algal biomass is expected to decrease due to decrease in surface water temperature.
Most recent results of the state of the Baltic Sea (algae, blue-green algae, nutrients, water temperature, salinity)
Algal bloom forecast
Taxonomic reports
