A post spring bloom situation was observed at most of the phytoplankton stations in the Skagerrak and Kattegat areas with low total cell counts and relatively high numbers of heterotrophic species like the dinoflagellate Peridiniella danica. At N14 though, a Pseudochattonella bloom was ongoing simultaneously with the heterotrophic dinoflagellate P. danica, causing elevated chlorophyll concentrations. In the Baltic Sea, spring bloom was observed at BY5 in the southern and BCSIII-10 in the eastern Proper Baltic with high cell numbers of diatoms and the dinoflagellate Peridiniella catenata. The species diversity was relatively high at the other Baltic stations as well, but cell numbers were low suggesting a pre or post bloom situation. There were definately nutrients available for phytoplankton growth.