ROLE OF ENVIRONMENTAL PARAMETERS IN THE DISTRIBUTION OF MEIOBENTHIC FAUNA (OSTRACODA AND FORAMINIFERA) IN THE ROMANIAN BLACK SEA SHELF

Abstract

With limited research undertaken on the distribution and biodiversity of meiobenthic fauna (living Ostracoda and Foraminifera) in the Black Sea, the present study has focused to create the baseline data for the Romanian Black Sea continental shelf. For this purpose, 9 short core samples were collected using a multi-corer in water depth ranging from 27.8 m to 41.8 m in May 2018 around the Sf. Gheorghe area (map sheet L35-120B). A total of 14 species were found belonging to Ostracoda (7 families), Cercozoa (one family), Foraminifera (5 families). The highest density of meiobenthic species was correlated with the highest concentration of CaCO3 where the substrate is dominated by a clayey silt or sandy silt while TOC concentrations were negatively correlated with the low densities occurring in the western part of the perimeter silt clay substrate is found. The density of soft-shelled foraminifera has a positive correlation with the concentration of salinity in the bottom water samples, and depth and a negative correlation with the bottom water temperature. The density of Ostracoda has a positive correlation with temperature and depth but a negative correlation with salinity in the bottom water samples. The relationships between high concentrations of CaCO3and increased abundances of meiobenthic fauna and high concentrations of TOC and low meiofauna abundances, respectively, reinforce the hypothesis according to which the dispersal of meiofaunal species is strongly influenced by environmental gradients. The data collected from Romanian Black Sea Shelf (Sf. Gheorghe Area) in the perimeter of the map sheet L35-120B, suggest another record of soft shelled monothalamous Foraminifera and Gromiidae group.