Geographical location of the study region. (A) The map of Russia showing location of the Bolshezemelskaya tundra (Bt). The numbers indicate the major studied systems of tundra lakes: 1 – the Kharbey lake system, 2 – the Padimeyskiye lake system, 3 – Lake Ambarty, 4 – the Vashutkiny lake system; 5 – Lakes of the Pechora River Delta; 6 – lakes of the More-yu River basin (lower reaches); 7 – lakes of the More-yu River basin (upper reaches); 8 – lakes of central part of Bt; 9 – Lake Ngosovey. (B) Insert showing the Kharbey Lake system: K1, K2, D1, D2, and L are small lakes adjacent to Lake Bolshoy Kharbey.