Seasonal variations in phytoplankton community of Manyas Reservoir (Balıkesir, Turkey) in relation to certain physical and chemical variables

Abstract

This study investigates the seasonal shifts in phytoplankton communities in the Manyas Reservoir (Balıkesir, Turkey) and their relationships with key physicochemical variables. A total of 59 taxa belonging to Heterokontophyta, Chlorophyta, Cyanobacteria, Euglenozoa, Charophyta and Miozoa were identified. The dominant species were Cyclotella meneghiniana, Fragilaria capucina, Nitzschia lorenziana, Navicula radiosa and Ulnaria acus from Heterokontophyta; Desmodesmus communis, Desmodesmus protuberans and Pediastrum simplex from Chlorophyta; and Trachelomonas volvocina from Euglenozoa. The analysis of the data clearly showed that electrical conductivity (EC), dissolved oxygen (DO), nitrate-nitrogen, total nitrogen (TN) and pH significantly shaped phytoplankton species distributions. The findings highlight the importance of hydrodynamics driving diatom dominance in turbulent zones contrary to the previous studies showing that high flow rates cause low diversity and abundance of phytoplankton in turbulent waters.