Algae report number 1, 2021

Type: Report
Author: Marie Johansen, Maria Karlberg


The phytoplankton diversity and total cell numbers were higher than expected for the season except at station Släggö where both total cell numbers and biodiversity were low. Diatoms dominated at all stations. Overall the diatom Pseudo-nitzschia* was common. The ichtyotoxic species Heterosigma akashiwo* that belongs to the Raphidophyceae was common at a couple of stations. The integrated chlorophyll concentrations were low but within normal for the month. At Släggö they were very low almost close to zero. The phytoplankton diversity and abundance were generally low at the Baltic stations and most stations were dominated by small cells and ciliates, and a few larger diatoms. BY2 had highest diversity, where in addition to all small cells, several larger diatoms species and dinoflagellates were found. BCSIII-10 and REFM1V1 had a few of the toxin producing Dinophysis acuminata* and BY38 some strains of the filamentous cyanobacteria Aphanizomenon sp. Overall, the integrated chlorophyll concentrations were low but normal for the month.