DETERMINATION OF EUTROPHICATION AND INDICATOR SPECIES BASED ON SEDIMENT DEPTH IN RELATION TO DIATOM INFERRED WATER QUALITY DATA IN LAKE TÖDÜRGE

Lake Tdrge located in Sivas Province is one of the most characteristic lakes with its high alkalinity in Eastern Anatolia.The lake is well known for its characteristic high water quality.The present study aimed to investigate the paleolimnological past of Lake Tdrge in relation to changes in concentrations of total nitrogen (TN), total phosforus (TP), chlorophyll-a (Chl-a), and secchi depth (Secc) that occurred in past years.Diatom-inferred paleolimnological evidence is also studied and evaluated.Core samples were taken from the lake using the Kajak Gravity Corer.The 113-year history of Lake Tdrge was re-dated using the Constant Supply Rate model (CRS) in the dating of 210 Pb.The TN, TP, chl-a, secchi depth, pH, and CaCO3 variables were reconstructed using weighted average (WA) transfer functions and modern analog techniques (MAT).Identifications and relative abundance of fossil/subfossil diatom species were made for each dated depth.A total of 104 diatom taxa belonging to 59 genera were identified.The relative abundance of diatom taxa was poor despite the high species diversity.Species diversity and relative abundance of species showed some variations in core samples dated between 2022 and 1909.Pantocsekiella comensis, Tetramophora Croatia, and Cymbopleura pyrenaica were found to be dominant diatom species in core samples.The relative abundance of the diatoms did not display considerable changes in the past 113 years.According to ecological assessments based on DI-TN, DI-TP, DI-Chl-a, and DI-Secc it has been determined that the lake has been eutrophic for 113 years.