The vertical profile of water temperature, dissolved oxygen, pH and conductivity in Lake Burdur, Turkey

This study was conducted in Lake Burdur (Turkey), a Na-Mg-(Cl)-SO sub(4)-HCO sub(3) type alkaline lake having 140 km super(2), surface area and 70 m maximal depth. Measurements of temperature, pH, dissolved oxygen, conductivity and salinity parameters were taken on monthly basis from the surface level to 30 m depth (in stratification period to 60 m) between December 2003 and November 2004. Epilimnion temperatures of the warm monomictic type Lake Burdur ranged seasonally between 6-25.3 degree C despite hypolimnion remained constant year round at 6-8 degree C, not forming a mixture at all. In the lake, thermal stratification was detected between May and October. Dissolved oxygen trend relative to depth is clinograde type, as in eutrophic lakes. In both periods, in which the stratification occurring or not, generally below 20 m a sudden drop of oxygen concentration and below 24 m anoxic conditions were found to be dominant. According to annual averages, epilimnion covered 0-7.5 m, while thermocline was between 7.5-12.5 and hypolimnion lower depths. According to measurements on 17.07.2004 to 60 m, pH at surface was determined as 9.15, at 35 m 9.35 and at 60 m again 9.15; conductivity at surface was determined 28.9, while at 60 m 30.86 mS/cm; salinity was found to be 17.8 at surface, 19.6 at 50 m, 19.1 ppt at 60 m.