Changes in the Species Diversity of Sandy Spit Mollusk Groups in the North of the Black Sea-Azov Basin Under the Influence of Ecological Changes in the Environment

Abstract

The topic of mollusk research is relevant in connection with ecological changes in the Black Sea-Azov basin. The human disturbance of natural processes degrades the condition of the water space and its inhabitants. Oppression by artificial environmental factors forces the transformation of animal organisms. Mollusks are the most sensitive organisms to changes in the environment. Therefore, their communities and particular species were studied in this study. The species diversity of mollusk communities in the thanatocenosis of sand spits of the northern part of the Black Sea-Azov basin was evaluated. The main morphological changes of shells in Anadara kagoshimensis and the Cardiidae family were analyzed. Material for the study was selected on the coastal emissions of the Sea of Azov (Fedotov spit) and the Black Sea (Dzharilgach spit near the village of Lazurne). As a result of the study, 458 shells of bivalves and gastropods were collected. The total sample of mussel shells from both habitats was 18 species, which were divided into 15 families. By morphometric traits of mussels Anadara kagoshimensis and the family Cardiidae, which was represented by three species of C. lamarcki, C. glaucum and C. umbonatum, it was possible to compile comparative histograms that characterized the overall size of the shells made it possible to identify patterns of changes in the size of shells depending on the ecological conditions of the habitat. Thus, for A. kagoshimensis, the Sea of Azov turned out to be more favorable living conditions as a result of morphometric measurements of mussels. Azov anadara is larger in size. The maximum size of the shell revealed that the maximum age of the Anadara was 5–6, maybe 7 years old. The age of the A. kagoshimensis from Black sea was not exceed 4–5 years. The histograms of morphometric traits of the shells of representatives of the Cardiidae family were similar to those A. kagoshimensis. In the Black Sea the shells were more abundant, indicating the extinction of populations in the first years of life the sturgeon forms. In the Azov sea the distribution of shells of the Cardiidae was evently distributed. The sea salinity was revealed to influence the size and age of A. kagoshimensis shells. They inhabit the soil, which is muddy and plastered. They were characterized by the pelagic type of growth. All species are euryhaline. Some species are domesticated in the bottom units. The results of the conducted research lead to the expansion of research in the future in order to monitor changes in mollusks communities under the influence of environmental processe