Algae report number 6, 2015

Type: Report
Author: Ann-Turi Skjevik


Fluorescence maxima in both Skagerrak and Kattegat areas were to a great deal caused by the dinoflagellate genus Ceratium. Unusually large numbers of C. macroceros was observed.

In the Baltic, the cyanobacteria surface accumulations had been muixed down in the water column by wind and waves. Filamentous (threadlike) cyanobacteria were abundant though at most stations, both surface samples and integrated (0-10m) samples. Nodularia spumigena* and Aphanizomenon flos-aque were both very common at most of the stations. Aggregations of cyanobacteria were visible as grains in the water in the northern Baltic Proper from east of the Gotska Sandön to BY15 in the Eastern Gotland Basin. Going southwards, grains reappeared in the Bornholm Basin. No grains were seen at BY1, the most western station in the Arkona Basins. Surface accumulations were only seen outside the Swedish south coast heading towards the Hanö Bight, but considering the observations the prediction is that calmer weather will lead to more surface gatherings. Phytoplankton analyses have been made on board the R/V Aranda with main focus on the cyanobacteria dominating in the Baltic bloom. The method used here is not the best for other plankton groups, but the organisms observed are reported.

To follow the surface accumulations of cyanobacteria in the Baltic Sea by satellite interpretations: