Summary
The phytoplankton situation in the Skagerrak and Kattegat areas was relatively stable compared to the sampling three weeks earlier. However, there were no chlorophyll fluorescence peaks to speak of. Only at W Landskrona on the edge of the Sound an extra phytoplankton sampling was made at 15 meters because of a peak in chlorophyll fluorescence measurement. In the Baltic, the cyanobacteria were abundant at all stations. In the southern Baltic, scattered surface accumulations were observed that grew and became more cohesive south-eastwards towards BCSIII-10. At all of the Baltic stations analysis showed that cyanobacteria were present in large amounts both at the surface and further down in the water. Nodularia spumigena dominated. Chlorophyll fluorescence peaks, which were associated with the thermocline, were mainly caused by the dinoflagellate Dinophysis norvegica and the chlorophyte Planctonema lauterbornii. To follow the surface accumulations of cyanobacteria in the Baltic Sea by satellite interpretations: http://www.smhi.se/vadret/hav-och-kust/algsituationen-1.11383 The phytoplankton samples were filtered through 10 µm polycarbonate filters before being analysed using a light microscope. Potentially toxic species are marked with *. To observe which of the cyanobacteria species were dominating the surface accumulations, bucket sampling was performed at most of the Baltic stations, and are listed on page 5. Small species were not analysed on board. Results of chlorophyll a, which will be analysed on land, will not be included in this report.