Sampling sites 1 within both systems are located where permafrost occurs (in the case of the Baydrag–Böön Tsagaan System — at the border between sparsely insular and sporadic permafrost, in the case of the Shargalyuut/Tuyn–Orog System at the border between discontinuous and insular permafrost). Sample 2 from both systems represent the zone where permafrost occurs in the form of sparsely insular or sporadic. Sample 3 in the case of the Baydrag–Böön Tsagaan System was collected at the terminal reach of the river flowing through an area of seasonally frozen ground.