MEIOBENTHOS OF THE BLACK SEA UNDER ANOMALOUS CLIMATIC CONDITIONS

Abstract

The results of the analysis of long-term studies of the meiobenthos of the northwestern shelf of the Black Sea (1994– 1999 and 2005–1015) are presented. It has been shown that the formation of the meiobenthic community depends not only on such environmental factors as the type of substrate, salinity, oxygen regime, and depth. The formation of its qualitative and quantitative characteristics is also influenced by periodic changes in climatic conditions. These changes are associated with changes in the processes that take place in the near-surface layers of marine areas. The article considers the dynamics of meiobenthos indicators that came for 15 years in the northwestern part of the Black Sea (Odessa Sea Region). The temperature of the surface layers of water, the dynamics of precipitation, and the runoff of the Dnieper River were taken into account. The interannual dynamics of the total abundance of meiobenthos and some of its large taxa (Foraminifera, Harpacticoida, Polychaeta) is described. The data obtained show that in the period of anomalous climatic conditions the maximum indicators of the nematode-copepod ratio and the total abundance of meiobenthos increases, whereas biomass decreases. The purpose of this article is to describe the formation of quantitative indicators of the meiobenthic community in anomalous climatic conditions. Our long-term observation of the formation of the meiobenthic community of organisms showed that under chronic constant anthropogenic impact, the species diversity of meiobenthos in the NWBS is sharply reduced, the dominance of the main groups (foraminifera and nematodes). The present data obtained show that for during years with anomalous climatic conditions, the maximum indicators of the Nnem/Nharp index nematode-copepod ratio are characteristic, it increases and, the total number of meiobenthos increases, and whereas the biomass decreases.