Algae report number 11, 2020

Type: Report
Author: Marie Johansen, Maria Karlberg


The phytoplankton diversity and total cell numbers were relatively low as can be expected for the season. The only exception was Å17 that had quite high biodiversity. Diatoms dominated at all stations except at Släggö where dinoflagellates were more abundant. Overall the diatom Pseudo-nitzschia* was common. At Å17, the outer most station in the Skagerrak, a few cells of species more commonly found in the North Sea were found. The integrated (0-10 m) chlorophyll concentrations that coincide with the depth of the hose samples were within normal for all stations. The integrated (0-20 m) chlorophyll concentrations were above normal at N14 Falkenberg and Å17 whereas they were just below normal at Anholt E.
The phytoplankton diversity was generally low at the Baltic stations and most stations were dominated by small cells and ciliates, and a few larger diatoms. BY15 and BY29 had highest diversity, where in addition to all small cells, several larger diatom species and green algae were found. Overall, the integrated chlorophyll concentrations were normal for the month, except for the South-Eastern stations BY5, BCS III-10 and BY10, where the concentrations were lower than normal.