Бидний тухай
Багш ажилтан
Meromictic lakes are lakes that do not have intermixed layers, and thus have unique physical, chemical, and biological properties. Lake Oigon is one lake with such a meromictic nature. However, a detailed study of the physico-chemical characteristics of Lake Oigon hasn’t been conducted. In this study, we investigated the physico-chemical characteristics of the water of Lake Oigon from the surface to bottom at one-meter depth intervals and compared parameter trends in summer and winter. The predominant hydrochemical type of lake water was Na-Cl-SO4. The salinity of the lake’s water was mesosaline to hypersaline. The concentrations of major ions (except sulphate) and microelements in summer were lower than that in winter. The suboxic layers (chemocline), and anoxic layer (monimolimnion) were often rich in nitrate, sulphide, ammonium, and phosphate despite the season. We hope that this study will show the characteristics of this meromictic lake and provide underlying information for future research on the chemical composition of Lake Oigon.
Determining vertical variation of water quality parameters is contributed to a better understanding of true nature of lakes. Lakes are classified into holomictic and meromictic lakes by their mixing mode; the former occurs physico-chemical mixing between surface and deep waters, while the latter layers of lake water occurs unmixed for years, decades, or centuries. Lake Oigon is the only meromictic lake identified in Mongolia. Few Mongolian lakes have been studied in different seasons but not in the vertical directions. Therefore, we studied the vertical profile of water and sediment parameters in Lake Oigon for two years. Physico-chemical parameters in water were measured on-site, while sediment parameters were determined off-site. Salinity in lake water ranged from 21.3 to 65.9 g/L which represented mesosaline to hypersaline. In oxic, sub-oxic, and anoxic zones, the physico-chemical parameters of Lake Oigon were varied a lot in longitudinal ways lake and seasonal variation observed as well. However, most parameters were stable in the anoxic zone, regardless of seasons, indicating that no water movement was at the bottom of lake. Layered sediments with salt indicating hardly exchange with lake water at the anoxic zone. The statistical correlation and principal component analysis between the various physico-chemical parameters of lake water and lake sediment were computed. This study provides the basic information for future research on the characteristic of the vertical profile, impact on the ecosystem, and environmental assessment for Lake Oigon.
Hydrochemical study in first lake meromictic discovered in Western Mongolia
