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. Key-Words: mesozooplankton, fodder, nonfodder, correlations, physicochemical "

Modelling Dynamic Processes in the Black Sea Pelagic Habitat -Casual Connections between Abiotic and Biotic Factors in Two Climate Change Scenarios

“…The model created by us within the project has 89 components and 203 linear connections (positive or negative) between them, connections that human thinking cannot make simultaneously to allow a clear analysis of the evolution of the pelagic component of the marine ecosystem, the concentrations of silicates and nitrates affecting the densities of meroplankton and copepods. Copepods are usually known as ammonium-excreting microorganisms, hence positive associations between copepods and nitrite (NO2) and nitrate (NO3) have also been documented [36,37].…”

“…This dinoflagellate produces impacts on the ecosystem in coastal areas around the world [47], generally in the spring and summer seasons when it registers high abundances, establishing the blooming phenomenon of the species [48]. The blooms generated by N. scintillans are closely related to food availability, especially to the presence of diatoms, which it consumes, controlling the dynamics of this phytoplankton group [37]. The phenomenon causes mortalities among fish, many of which are of economic importance, as well as marine invertebrates due to the accumulation of high levels of ammonia in the water [49].…”