Uvs Nuur: A Sentinel for Climate Change in Eastern Central Asia

Abstract

The Uvs Nuur is located in Northwest Mongolia bordering with Russia. It is the largest lake of Mongolia (5.5 times larger than Lake Constance in Southern Germany), but not the deepest. The diameter of this round-shaped lake is ca. 80 km and its eastern shoreline is located 1300 km west-northwest of the capital city Ulaanbaatar. Studies in the Uvs Nuur Basin show that past lake-level fluctuations may have been triggered by climate change and/or by changes in the catchment hydrology such as the damming of tributaries by mobile dunes. Direct human impacts on the lake level and water quality of Uvs Nuur due to recent mining or other industrial activities were not identified till now. Increasing pasture load by livestock breeding in the lake-near areas, withdraws of river water for irrigation and increasing tourism infrastructure with insufficient wastewater management need to be under control in the future to maintain the pristine state of Uvs Nuur. The Holocene lake development shows remarkable higher and lower lake levels. There were higher lake levels at Uvs Nuur and Bayan Nuur in the middle Holocene in accordance with most Mongolian lakes. Late Holocene lower levels were identified at Uvs Nuur at -8 m and lower. The recent (2018) tendency of the lake level is slightly negative after a high level at the beginning of the new century (2000). The biological and hydrological data for Uvs Nuur confirm its natural status as a hyposaline, temperate dimictic lake with sometimes polymictic periods in the summer. The investigations show a fully adapted biological inventory of organisms and natural physical and chemical attributes for lake and river waters in accordance with the specific climate and drainage area conditions.