Summary
Spring bloom was ongoing at Å17 in the open Skagerrak with high cell numbers of the diatom Skeletonema marinoi. Other cell numbers were surprisingly low considering the high chlorophyll concentrations. At Släggö the phytoplankton diversity was still low. Spring bloom was observed even in the Kattegat area, with S. marinoi having the highest cell counts. The highest diversity and total cell numbers were found at N14 Falkenberg. Among the Baltic stations it was only at REFM1V1 the spring bloom was imminent, with a dominance of S. marinoi. In spite of this the chlorophyll concentrations were below normal at this station. The other stations had low diversity and the phytoplankton community was composed of relatively small cells, which was represented in the low but normal chlorophyll concentrations for the month of February.