EKOLOJI, cilt.20, sa.80, ss.23-32, 2011 (SCI-Expanded)
The determination of the spatial and temporal variations of phytoplankton populations contribute to set up lake management strategies. It was aimed to investigate the biomass of phytoplankton of large and shallow Lake Beysehir. The lake was sampled monthly from four selected stations and surface, mid and deep layers between March and December 2007. The phytoplankton biomass was estimated from counted cell size. A total of 119 phytoplankton species from Bacillariophyta (42), Chlorophyta (48), Chrysophyta (1), Cryptophyta (4), Cyanobacteria (9), Pyrrophyta (5) and Euglenophyta (10) were identified. Total phytoplankton biomass consisted of Bacillariophyta (53%), Chlorophyta (27%), Chrysophyta (3%), Cryptophyta (2%), Cyanobacteria (10%), Pyrrophyta (4%) and Euglenophyta (2%). Mean values of chlorophyll a, total phosphorus and Secchi depth were measured as 8.24 +/- 2.08 mg/m(3), 10.46+/-6.20 mg/m(3) and 1.08+/-0.35 m, respectively. Dissolved oxygen was measured between 6.36+/-0.06 and 11.63+/-0.06 mg/l. varied between 7.80+/-0.01 and 8.92+/-0.01. Water temperature changed between 5.3 degrees C and 27.8 degrees C. In the study period, phytoplankton biomass of Lake Beysehir varied between 0.40+/-0.11 and 6.43+/-1.00 mg/L. The mean phytoplankton biomass (1.98+/-1.18 mg/L) of the lake pointed out mesotrophy and good ecological quality class.