The concentration of total organic carbon varied between 2 and 12.2 mg/l. The highest content was found in the Blagodati and Golubichnoe Lakes due to the inflow of organic matter related to bog creation, and the lowest content was in the water of Vaskovskoe Lake (Table 2). The carbon content in DOM was 2.3–8.4 mg/l (average of 5.2 mg/l), and so 68–90% of the total carbon was found in the dissolved organic matter of the lakes.