PELAGIC ALGAL COMMUNITIES IN THE SEA OF AZOV

This paper presents a series of generalizations and conclusions, based on analyzing literature and historic data derived from multi-year observations, which characterize general regularities, patterns, and features of how pelagic algal communities in the Sea of Azov are structurally organized and function, as well as their seasonal variabilities and cyclical events in their annual evolution. To date, different authors report more than 700 species among types and forms of planktonic algae inhabiting the Sea of Azov, representatives of Bacillariophyceae, Dinophyceae, Cyanophyceae, Chlorophyceae, Chrysophyceae, Cryptophyceae, Euglenophyceae, Prymnesiophyceae, Prasinophyceae, and Xanthophyceae. Diatoms and green algae are absolute dominants both in taxonomy and in forming gross phytoplankton biomass in the Sea of Azov. Spring, autumn, and winter periods are dominated by diatoms; dinophytes, diatoms, and green algae dominate in summer. The pelagic algal community reaches its maximum development in spring; diatoms form the major part of phytoplankton biomass producing more than 80 % of the total. As a whole, the algal community in the Sea of Azov can be characterized as an oligohalobe complex of cosmopolitan species, which is formed with a substantial participation of tropic, boreal, and arctoboreal forms. The paper suggests the concept of the annual successional growing cycle of pelagic algal communities as a base-line scheme. In the annual successional cycle of microalgae in the Sea of Azov one can clearly identify 4 phases: the phase of blooming of sympagic and sub-ice microalgae, the spring growing cycle, the phase of summer–autumn balanced development, and the winter dormant phase.

phytoplankton, Sea of Azov, pelagic, successional cycle