Phyto- and zooplankton of the southeastern Barents Sea in April 2000

Spring bloom of cold-water centric and pennate diatoms was observed in two different areas of the southeastern Barents Sea in April 2000: ice-free waters off the Kolguev Island northern shelf and the eastern Pechora Sea near the Karskie Vorota (Kara Gate) Straight in polynyas and ice-free patches in one-year-old ice. Maximal values of phytoplankton abundance and biomass were found at the ice edge. The bloom was localized in shallow water areas with depths less than 50 m in mixing zones of waters of different origin: warm Atlantic, cold coastal, and Arctic (Litke current) waters. Ice melting was among factors inducing the phytoplankton bloom. Each area had a specific phytocoenosis, whose structure was determined by water origin and ice conditions. In the western Kara Sea, under a solid (up to 30 cm thick) ice cover (i.e., under conditions of a hydrological winter), a spring phytoplankton succession was observed from its initial stage. In areas located close to the ice-cover edge, simultaneously with the mass phytoplankton bloom, the early spring zoocoenosis development manifested itself in mass spawning of euphausiids and mass appearance of Cirripedia nauplii and bottom polychaete larvae.

Abundance and biomass of mesozooplankton collected in front of the Danube Delta in April and September 1977

The Gurile Dunarii 1977 dataset contains zooplankton data collected in April and September 1977 in 14 station allong 3 transect in front of the Danube Delta. Zooplankton sampling was undertaken at 14 stations where samples were collected using a Juday closing net in the 0-10, 10-20, 20-30, 30-40 and 40-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.