Вестник МГТУ. 2017, №2.

Вестник МГТУ. 2017. Т. 20, № 2. С. 316–325. DOI: 10.21443/1560-9278-2017-20-2-316-325 325 P. R. Makarevich, A. A. Oleinik Microplankton of the Barents Sea: current composition and structure on the eve of the winter The results of microplankton (Protista) investigations in the Barents Sea (standard "Kola Meridian Transect", ~70–78° N, 33° 30′ E) in November / December have been presented. Samples for the determination of the taxonomical composition and abundance have been fixed with buffered formalin and examined with light microscopy using Nageotte counting chambers. A list of species recorded in the Barents Sea on transect, abundance and vertical distribution of microplankton has been given: a) the seasonal composition of species ( Ceratium fusus , Dicroerisma psilonereiella , Dinophysis rotundata , Lessardia elongata aff., Oxytoxum caudatum , Pronoctiluca pelagica , Protoperidinium brevipes , Prorocentrum balticum (Dinophyta), Corethron criophilum (Bacillariophyta), Coccolithus pelagicus (Haptophyta), Halosphaera viridis (Prasinophyta)); b) mean values of the total biomass of microplankton and its distribution in the water column (1.14 mkg/l in the layer of 50–0 m, 0.97 mkg/l – 100–50 m, 0.75 mkg/l – 200–100 m, 0.53 mkg/l – 300–200 m). Such parameter as dominant species in the structure of the total number is less constant (the ordinary dominant O . caudatum , subdominants – L. elongata aff., P. balticum , C. pelagicus , C. criophilum ); in some years, at selected sites of the Barents Sea most of the total number has been formed to unusual species ( Emiliania huxleyi , Mesoporos perforatus ). The less stable characteristics of microplancton are dominant species composition in the biomass structure, total number of cells and their distribution in the water column. Key words: microplankton, Protista, seasonal composition of species, number of cells, biomass, Barents Sea.