Summary
The diatom Proboscia alata was found in relatively high concentrations at all stations in the Skagerrak. One or two chlorophyll maxima were found at all stations, mainly caused by the dinoflagellate genus Ceratium. At a couple of stations quite high densities of the fish killing species Karenia mikimotoi were found. Diatoms were very common in the Kattegat area, and Proboscia alata was abundant at all stations. The diatoms Skeletonema marinoi and small Chaetoceros species were common at N14 Falkenberg. The dinoflagellates Prorocentrum micans and Ceratium fusus were rather common. There were visible surface accumulations of filamentous cyanobacteria in the southern parts of the Baltic Sea between Bornholm and Öresund. Filamentous cyanobacteria were present as small grains in the water at the first sampling points in the outer parts of the Finnish Bay and in small amounts east of Gotland. At BY5, the Bornholm Basin, surface accumulations with streaks of different sizes started to appear and continued to appear until Öresund. Aphanizomenon flos-aqua was the most abundant of the filamentous cyanobacteria in the Finnish Bay, but Nodularia spumigena* increased in concentrations going south. The surface accumulations had grown to larger areas in the southern parts of the Baltic when going back (fig. 2). Irregular areas of surface accumulations in the shape of lighter green to more intense orange coloured patches or streaks could also be seen between Öland and Gotland and, as approaching the entrance of the Finnish Bay.
Please follow the link below to see interpretations of blooms from satellite images in the Baltic: http://www.smhi.se/en/weather/sweden-weather/1.11631