Assessment of the zooplankton community structure of the coastal Uzungol Lagoon (Kizilirmak Delta, Turkey) based on community indices and physicochemical parameters

The objective of this study is to provide information on the zooplankton community and physicochemical properties of Uzungol Lagoon. Sampling studies were performed at monthly intervals for abiotic factors and community parameters between September 2015 and August 2016. The variations of zooplankton community were estimated using Shannon-Weiner diversity (H'), Pielou evenness (J), species richness (S), frequency, and dominancy indices. The relationship between environmental variables and community parameters were analyzed with Pearson's correlation test and redundancy analysis (RDA). During the study, 39 species, most of which belonged to Rotifera, were recorded. The quantitative analysis indicated that most important fraction of zooplankton were small-sized rotifers with low filtration rate. The species belonging to Rotifera reached their most important numerical maximum in February. Dominant organisms in the zooplankton community were found to be Filinia terminalis, Keratella quadrata, Brachionus angularis, and Polyarthra vulgaris. The relatively low diversity and evenness values resulted from a clear dominance of few species in the zooplankton community. Temperature had a positive effect on diversity and species richness, but increasing salinity had a negative effect on these indices. RDA biplot indicated that Anuraeopsis fissa, Hexarthra mira, Keratella tropica, and Polyarthra vulgaris were positively correlated with temperature. Additionally, Keratella cochlearis and Keratella quadrata were positively correlated with dissolved oxygen (DO) and negatively correlated with temperature. A negative correlation was found for pH with Filinia longiseta and Keratella quadrata.