Summary
The spring bloom was in its final phase in the Kattegat-Skagerrak areas. The chlorophyll concentrations were high and typical spring bloom diatoms were present, but the nutrients were completely or almost completely exhausted, which is why the bloom was predicted to end soon. Chlorophyll fluorescence maxima were dominated by diatoms and the integrated (0-20 m) chlorophyll concentrations were normal for this month. The spring bloom was ongoing in the southern Baltic with dominance by the diatom Skeletonema marinoi. There was enhanced activity amongst phytoplankton in the surface waters at the other Baltic stations as well, which probably meant that the spring bloom was just starting. The integrated (0-20 m) chlorophyll a concentrations were above what is normal for this month at stations BY4, REF M1V1 and BY38 and normal at the rest of the Baltic stations. For more information about nutrients etc, see the latest cruise report:
http://www.smhi.se/en/publications/cruise-reports-from-the-marine-monitoring/cruise-report-from-r-v-aranda-week-11-12-2016-1.102598