ФИТОПЛАНКТОН ОТКРЫТОЙ СЕВЕРО-ВОСТОЧНОЙ ЧАСТИ ЧЕРНОГО МОРЯ В ЗИМНИЙ ПЕРИОД 2017 г.

Abstract

The seasonal dynamics of phytoplankton development in winter is less studied than in other seasons, therefore it is of certain interest. The article presents the results of the study of taxonomic structure and the level of quantitative development of phytoplankton in the open area of the Black Sea northeastern shelf in December 2017. 34 Species belonging to 5 divisions of Bacillariophyta, Dinophyta, Chrysophyta, Cryptophyta and Chlorophyta were found in phytoplankton. The maximum species diversity was recorded among Dinophyta (21 species) and Bacillariophyta (8 species), other divisions were represented by 1–2 species. Previous studies have shown that the taxonomic composition of phytoplankton in the open area of the Black Sea northeastern part includes a large number of dinophytic species, while the diversity of diatoms is significantly inferior to them. The abundance and biomass of planktonic algae were extremely low during the study period (on average, 2706 cells / liter 11.49 mg / m3 ). The maximum abundance of species (26) and the highest values of quantitative development (5399 cells / l and 32.27 mg / m3 ) were observed in the area of the Taman Peninsula. These values were 2–4 times higher than the values of abundance and biomass found in the rest of the study area. The abundant development of planktonic algae was probably facilitated due to the ingress of waters of the Azov Sea, richer in nutrients, into the Kerch region of the Black Sea. Bacillariophyta (Pseudo-nitzschia pseudodelicatissima, P. seriata, Thalassionema nitzschioides, Pseudosolenia calcar-avis, Ditylum brightwellii), and Dinophyta (Prorocentrum cordatum, Prorocentrum micans and Ceratium species) formed the basis of the abundance (55 and 23 %, respectively) and biomass (24 and 68 %) of phytoplankton. Cryptophyta (Plagioselmis prolonga and P. punctata) accounted for 16 % of the phytoplankton population during the study period. Among the Chrysophyta and Chlorophyta, the species Octactis octonaria and Pterosperma undulatum, common for the open part of the Black Sea, were observed in small quantities. The favorable ecological situation in this region of the sea is proved by the complete absence of Cyanophyta and Euglenophyta, which are indicative of polluted and desalinated sea areas.