Abundance of phytoplankton communities of the Barents Sea in the first half of the growing season of 2013

Information on the abundance and biomass of phytoplankton communities of the Barents Sea in the summer of 2013 has been considered. Sampling has been carried out on board the research vessel "Professor Molchanov" in the course of the expedition "Arctic Floating University - 2013" in June, 2013 in the west (Kola Meridian), north-west, north (Franz Josef Land) and northeast (Novaya Zemlya) areas of the Barents Sea. The water samples have been collected from 32 stations on the surface layer of the sea water and from the layer of sharp changes in the density and temperature of the water - pycnocline - which lies at the depth of 20 to 50 m. Abundance and biomass of phytoplankton in the surface layer have varied from a few dozen to 74 thousand cells/L and 2.5 to 3 900 mkg/L; above the pycnocline layer - from several hundred to 63 thousand cells/L and from 0.9 to 3 000 mkg/L. As for the spatial distribution the greatest number of phytoplankton cells has been noted in the western region and the waters in the area of Franz Josef Land Archipelago, and the largest biomass - only in the western region. The average population size above the pycnocline layer is higher than in the surface layer, the average values of the biomass in two horizons are identical. Representatives of the two phylums of algae Bacillariophyta and Dinofita have been dominated in numbers in varying degrees in different areas. Diatoms are the main biomass formed in the northern part of the sea. Dinoflagellates have formed the main biomass in other regions in both the Barents Sea water horizons column.