Summary
Both stations in the Skagerrak had high total cell abundances and high biodiversity. Different species of diatoms dominated the coastal phytoplankton community, of which the common chain forming diatom Skeletonema marinoi was the most abundant. The off-shore station was, however, dominated by the coccolithophorid Emiliania huxleyi. The two stations in Kattegat had high total cell abundances and high biodiversity, and mainly consisted of diatom species, of which S. marinoi was the most abundant species. The integrated chlorophyll concentrations were, generally speaking, in the lower range of what is normal for this month.
Among the Baltic stations the spring bloom had started at the southern stations, especially at BY2, REFM1V1 and BCSIII-10, which was reflected in high chlorophyll concentrations and high amounts of S. marinoi and other typical spring bloom species. At the other stations both the chlorophyll concentrations and species composition indicated that the spring bloom had not started yet.