Phytoplankton composition of lake ketence

Keywords: Canonical Correspondance Analysis, Lake Ketence, Phytoplankton, Water Quality The purpose of this study was to determine species composition and the biomass of phytoplankton, and the variations in the main physical and chemical parameters affecting phytoplankton distributions in Lake Ketence. Monthly sampling was carried out at 2 stations between October 2016 and September 2017. Water temperature, specific conductance (SC), total dissolved solid (TDS), pH and dissolved oxygen (DO) were measured monthly using a YSI proplus water probe. Water transparency was determined monthly using a Secchi disk during the sampling. Nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N), orthophosphate (PO4- P), total phosphorus (TP) and silica (SiO2) were analyzed monthly according to standard methods. The identification and counting of phytoplankton were carried out using an Olympus BX51. For counting, a Palmer-Maloney phytoplankton counting chamber was used. The biomass was calculated from the biovolume of cells. Mean values of measured parameters in Lake Ketence were as follow: water temperature 18,1 °C, SC 404,7 µS cm-1 , TDS 306,7 mg L-1 , pH 8,6, DO 6,5 mg L1 ,Secchi disk 78,4 cm, NO3-N 0,41 mg L-1 , NO2-N 0,006 mg L-1 , PO4-P 0,02 mg L-1 TP0,06mg L-1 ,SiO2 0,008 mg L-1 . During the course of the study, a total of 92 taxa in 8 divisions have been identified, including 26 species in Bacillariophyta,2species in Charophyta,28 species in Chlorophyta, 4 species in Cryptophyta, 8 species in Cyanobacteria, 16 species in Euglenozoa, 6 species in Miozoa and 2 species in Ochrophyta. Cryptomonas erosa, Trachelomonas volvocina, Cyclotella meneghiniana, Ulnaria acus, Glenodinium gymnodinium, Apocalathium aciculiferum, Pantocsekiella ocellata, Peridiniopsis cunningtonii, Phacus longicauda, Euglena rubra,Naiadinium polonicum, Tetraëdron minimum, Trachelomonas oblonga, Euglenaria clavata and Euglena chlamydophora species were dominant in phytoplankton during different time of the study period. Dominant species were separated in 4 groups in consequence of physical and chemical variables in Canonical Correspondance Analysis. The water quality of lake is classified as I and II based on physical and chemical parameters. However, considering the total algal biomass, phytoplankton composition and the dominancy of Euglenozoa species, the water quality of the lake is supposed to be eutrophic.