Summer season variability of dissolved oxygen concentration in Antarctic lakes rich in cyanobaterial mats

Since 2007, limnological investigation of terrestrial lakes has been carried out at James Ross Island, Antarctica. The lakes in scope differ in their size, origin, geomorphological and hydrological characteristics. In several selected lakes, dissolved oxygen is measured repeatedly each summer season in order to quantify lake- and weather-related differences. For this study, typical reresentatives of (i) coastal shalow lakes, and (ii) high-altitude lakes with cyanobacterial mats were chosen. We present data on dissolved oxygen measured in 3 d interval during January 2010. Within this time, water temperature decreased gradually from 13 to 3oC, as well as dissolved oxygen concentration. It varied within in the range of 12.50-18.0 mg l-1 indicating the values close to saturation and suprasaturation, respectively. Dissolved oxygen concentration showed slightly decreasing trend in a course of time. In majority of cases, the lakes with rich cyanobacterial flora showed higher dissolved oxygen concentrations than Lachman Lake 2 which posses less cyanobacterial mats than other the lakes involved into the study. Due to air temperature decrease, Dulanek lake, a high-altitude lake, froze in the last week of January 2010