HYDROCHEMICAL FEATURES OF THE SOUTH DOBROGEA'S LAKES AND IMPACT OF THE CLIMATIC CONDITIONS ON THESE FEATURES

Camelia Eliza Telteu

University of Bucharest, Faculty of Geography, Bucharest, Romania

Abstract

The present paper presents some hydrochemical features of the South Dobrogea's lakes. The study includes the lakes on the Black Sea shore (Siutghiol, Tăbăcărie, Techirghiol and Tatlageac) and on the right side of the Danube River (Bugeac, Oltina, Mârleanu, Iortmac şi Vederoasa). The analysis is based on the processing of data concerning the hydrochemical parameters for the years 2006 – 2008 (the data were provided by the "Romanian Waters" National Administration) and the data regarding the pH, the dissolved oxygen (mg/l), the total dissolved solids (g/l) and the salinity (g/l), obtained during summer 2011 (with Hanna intrument HI 9828). The concentration of the major ions are: chlorine (51.78 – 33737 mg/l), sulfate (50.93 – 6296 mg/l), magnesium (38.30 – 2470.42 mg/l) and calcium (25.93 – 206.40 mg/l). The values of the total mineral nitrogen (0.925 – 3.384 mg/l), of the total phosphorus (0.069 – 0.673 mg/l), of the phytoplankton biomass (5.99 – 19.46 mg/l) and of the chlorophyll "a" (44.590 – 601.449 µg/l) include the lakes to the eutrophic and hypertrophic status. In case of the Bugeac, Oltina and Siutghiol lakes, the analyze highlights statistically significant correlations, α = 0.05, between the precipitation (for 10 days, 20 days and 30 days), the daily air temperature and some hydrochemical parameters. Applying Carlson's Trophic State Index, based on the lakes's transparency values during summer 2011 (which were estimated with the Secchi disk), the Bugeac, Oltina, Mârleanu and Tatlageac lakes belong to the hypertrophic status.

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