Seasonal dynamics of micro- and mesoplankton of the Temryuk estuarial pelagic ecosystem of the Sea of Azov

Abstract

The variability in the composition and dynamics of microplankton (ciliate) and mesoplankton in the Temryuk estuarial pelagic ecosystem has been studied at different stages of succession of the pelagic communities. Invertebrates of 54 taxa, including ciliates of 24 taxa, have been identified. Among the ciliates, Myrionecta rubra, Mesodinium pulex, Halteria grandinella, Strombidium conicoides, S. sp. 1, S. sp. 2, Strobilidium sp., Loxmaniella oviformis, and Tintinnopsis minuta were dominant. The share of mesoplankton in the total biomass of zooplankton reached 70% (1.3 g/m3) and was estimated as the maximal value for mesoplankton of the Sea of Azov. Marine and brackish-water rotifers of the genus Synchaeta and Asplanchna priodonta constituted 55% of the biomass. The most abundant meroplanktonic larvae of Amphibalanus improvisus amounted to 30% of the total mesoplankton biomass. In the seasonal dynamics of microplankton development, two peaks of the biomass were revealed: spring (0.45 g/m3) and more expressed summer (0.9 g/m3); in mesoplankton there was one spring peak (3.7 g/m3). Superdense communities of ciliates and detritophages in some periods of the vegetative season are typical for the hypereutrophic ecosystem and can testify to the catastrophic character of its transformation.