The Assessment of the Mesozooplankton Community from the Romanian Black Sea Waters and the Relationship to Environmental Factors

Abstract

The paper aims to develop and test a semi-quantitative method that generates scenarios for the zooplankton community development under salinity and nutrients fluctuations. First, we identified the relationships between the mesozooplankton component and the environmental factors by analyzing data (N=2566) collected within the warm season (May-September) of a decade (2008-2018). The biotic and abiotic parameters were investigated at 37 stations within the monitoring network of the Romanian Black Sea waters, covering all three marine reporting units (waters with variable salinity, coastal and marine) according to Marine Strategy Framework Directive (MSFD). We identified 32 mesozooplankton species belonging to ten taxonomic classes, copepods representing the bulk of the community. In waters with variable salinity and coastal waters, the fodder component of the mesozooplanktonic community was dominant, while in marine waters the nonfodder component was better and exclusively represented by Noctiluca scintillans. Physicochemical parameters that showed significant correlations with the mesozooplankton species were S (salinity) and nutrients - NO2- (nitrite), NO3-(nitrate), PO43-(phosphate) and NH4+(ammonium). The number of species significantly correlated with the physicochemical parameters showed variations generally correlated with the increasing salinity gradient: in waters with variable salinity nine species being correlated, in coastal waters ten species, and in marine waters five species.