Summary
In the Skagerrak, both cell abundance and diversity were low at Å17, the diversity was however higher at Släggö. At Släggö the toxin producing dinoflagellate Dinophysis norvegica* was present in quite high cell numbers. In Kattegat, at the first sampling occasion at Anholt E the water was stratified down to 10 m, the depth at which phytoplankton are sampled. This resulted in high cell numbers. At the second sampling occasion the water column had been mixed, resulting in a more normal phytoplankton community. N14 had low cell abundance and diversity. The integrated chlorophyll concentrations were normal at all stations, except at the first sampling occasion at Anholt E, where they were higher than normal. Among the Baltic stations the spring bloom was coming to an end. Some typical spring bloom species were still present though, such as Skeletonema marinoi and Peridiniella catenate. There were also a lot of “post spring bloom species” such as Gymnodiniales and Dinobryon sp. BCSIII-10 was the only station where the filamentous cyanobacteria Aphanizomenon flosaquae was present and at all other stations the toxin producing Dinophysis acuminata* was found. The integrated chlorophyll concentrations were normal at all stations indicating the end of the spring bloom.