The Effects of Water Quality Parameters on Summer Dynamics of Phytoplankton and Zooplankton in the Tributaries of Murat River (Hınıs, Erzurum)

This study aimed to investigate the spatial variations in phytoplankton and zooplankton composition in relation to selected water quality parameters across five tributaries of the Murat River. The research encompassed physical and chemical parameters, chlorophyll-a levels, zooplankton and phytoplankton composition and biodiversity indices within the tributaries. A total of seven zooplankton species were identified, comprising 40% Copepoda, 37.14% Cladocera and 22.86% Rotifera, with Cyclops vicinis emerging as the dominant species. Additionally, 34 species from the Bacillariophyta, Chlorophyta and Cyanobacteria groups were recorded. The Shannon-Wiener and Margalef Biodiversity Indices revealed that zooplankton diversity peaked at the 5th station, while phytoplankton diversity was highest at the 3rd station. The average concentrations of total phosphorus (TP) and ammonia nitrogen (NH3-N) were measured as 5.93 mg L-1 and 3.02 mg L-1, respectively. Chlorophyll-a values ranged from 0.001 mg L-1 at the 1st station to 0.011 mg L-1 at the 5th station. According to the Trophic Diatom Index (TDI), the water quality was categorized as poor, while other indices indicated medium water quality. In conclusion, the findings highlight that the tributaries of the Murat River are under significant threat from anthropogenic pollution. Urgent mitigation measures are recommended to safeguard these water resources.