Taxonomic composition and abundance of planktonic algae in the West Antarctica waters (February-March 2020)

Diversity, quantitative development and distribution of phytoplankton species were investigated. The study area included southeastern part of the Ross Sea (near Roosevelt Island) (station 3), transect 1 along the 156°W (Ross Sea at Cape Colbeck), near Russkaya station (transect 2) along the 138°W and the Bransfield Strait (transect 3) in February-March 2020, based on the data of 65th Russian Antarctic Expedition. 49 algae taxa from 7 divisions with a predominance of diatoms were identified in the phytoplankton. The spatial distribution of phytoplankton was characterized by heterogeneity which is associated with currents in the study areas, ice conditions, climatic and thermohaline factors. Development of diatoms is typical to the entire studied area. The dominant species (more than 10% of the algae population) were representatives of the genera Fragilariopsis, Chaetoceros, Actinocyclus, Corethron and Phaeocystis. The highest phytoplankton abundance (up to 264×103 cells/l) were obtained for transect 2 stations.