Chemical Composition Of Lake Water Research Articles

Variability of sedimentary phosphorus composition across Canadian lakes

Phosphorus (P) in lake sediments is stored within diverse forms, often associated with metals, minerals, and organic matter. Sediment P can be remobilized to the water column, but the environmental conditions influencing the P retention-release balance depend upon the sediment chemistry and forms of P present. Sequential fractionation approaches can be used to help understand forms of P present in the sediments, and their vulnerability to release. We assessed P composition in surficial sediments (as an assemblage of six P-fractions) and its relationship with watershed, and lake-specific explanatory variables from 236 lakes across Canada. Sediment P composition varied widely across the 12 sampled Canadian ecozones. The dominant P-fractions were the residual-P and the labile organic P, while the loosely bound P corresponded to the smallest proportion of sediment TP. Notable contrasts in sediment P composition were apparent across select regions – with the most significant differences between sediment P in lakes from the mid-West Canada region (Prairies and Boreal Plains ecozones) and both Eastern coastal (Atlantic Maritime and Atlantic Highlands) and Western coastal (Pacific Maritime) ecozones. The ecozone attributes most critical to sediment P speciation across Canadian lakes were related to soil types in the watershed (e.g., podzols, chernozems, and Luvisols) and the chemical composition of lake water and sediments, such as dissolved Ca in lake water, bulk sedimentary Ca, Al, and Fe, dissolved SO4 in lake water, lake pH, and salinity. Understanding predictors of the forms of P stored in surficial sediments helps advance our knowledge of in-lake P retention and remobilization processes across the millions of unstudied lakes and can help our understanding of controls on internal P loading.

High Vegetation of Lake Ayakagitma in Bukhara Region and Their Distribution

More than 500 lakes are found in Uzbekistan. Ayakagitma Lake is located on the border of the Northern Gijduvon and Shafirkon districts of Bukhara region. This lake was formed in 1985-1986 at the expense of the waters of the sewage dump collector. The area of the lake is 8200 hectares, the maximum depth is 35 m, on average 10 - 15 m, the minimum is 3 - 5 meters. The chemical composition of lake water is chloride-sulfate and has a calcareous character. 67 species of high plants belonging to 22 families were found in this area. 17 of these species are found in the water of the lake and 50 species are found around it. Of the most common species, Phragmites communis reach a height of 4.5 - 5.5 meters. Phragmites communis make up the total area of the lake 8 - 10 hectares.

High Altitude Lake and Hydrochemistry: A Study of Lam Dal and Six Consecutive Lakes of Dhauladhar, Himachal Himalaya, India

Increased human influence has warmed the atmosphere, ocean and land thereby resulting in widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere (IPCC, 2021). High altitude lakes are generally small and quite sensitive to natural and anthropogenic perturbations. The present work is a preliminary work to investigate different hydro chemical processes and factors that controls the geochemistry of a high altitude lake, Lam Lake (dal) and its consecutive six lakes flowing through the Chamba district, Himachal Pradesh. Two hundred and eighty (n=280) water samples were collected in the year 2017 during the pre-monsoon and post-monsoon season. The anion concentration for all the seven lakes followed the trend HCO3- > NO3- > Cl- > SO42- > PO43- whereas the order of cation concentrations was Ca2+> Mg2+> Na+> K+ for both the seasons. Less EC of the water samples shows its serene nature. Components of bicarbonate (HCO3-) were found to be the major anion whereas calcium (Ca2+) was found to be the major cation present in the lakes. Piper Plot and Durov plot indicated Ca2+ – HCO3- as the major hydrogeochemical facies with comparatively less contribution from Mg2+–HCO3- type. The dominance of Ca2+ – HCO3- over Mg2+– HCO3- reflects the possibility of the natural order of dominance in the geology of the catchment area. The low Na+ + K+/TZ+ (total cations) ratios and the high Ca2+ + Mg2+/TZ+ (total cations) and (Ca2+ + Mg2+)/(Na+ + K+) ratios showed dominance of carbonate weathering. The average carbon ratios during pre-monsoon and post-monsoon were found to be 0.97 and 0.98, respectively, suggesting that proton is primarily derived from the oxidation of sulphide involving carbonate dissolution. The baseline data generated for a high-altitude lake shows that weathering and erosion during monsoonal precipitation and snow melt runoff during ablation season are the main sources of the chemical composition of lake water. Further to trace the imprints of climate change and seasonal variations in the high-altitude lakes, long term monitoring is recommended along with isotopic tracer techniques.

Current chemistry of Lake Onego and its spatial and temporal changes for the last three decades with special reference to nutrient concentrations

Lake Onego is the second largest freshwater lake in Europe experiencing a multifactorial impact. The environmental pressures on the lake ecosystem has changed over the last decade because of the intensive development of aquaculture, reduction of wastewater discharges, internal load, and population redistribution. The purpose of this study was to assess whether these changes have affected the water quality of Lake Onego and to assess their extent. Data collected in 2019–2021 were used to indicate distribution and spatial heterogeneity in the chemical composition of lake water. The following parameters were considered: pH, conductivity, total suspended solids (TSS), Na+, Cl-, nutrients (P-PO4, TP, N-NH4, N-NO3, TN), organic matter (OM) (TOC, lignosulfonates, BOD5, CODMn, CODCr, color), Fe, Mn, and heavy metals (Cu, Ni, Zn, Cd, Pb). Data collected earlier (1992–2018) were used to indicate temporary changes in nutrients and OM concentrations. The largest tributaries deliver nutrients, TSS, and OM associated with Fe, Mn, and Cu to the lake water. Water contamination was observed in the Petrozavodsk and Kondopoga Bays experiencing anthropogenic load from domestic and Pulp and Paper Mill wastewaters accordingly, which is mainly evidenced by increased concentrations of OM and nutrients. The water quality in the Petrozavodsk Bay is significantly deteriorated in winter and spring due to the Shuya River discharge, which caused an increase in TP and OM concentration in the bay in the last three decades. Gradual increase in TP and OM content since 1992 also been observed in the central part of the Kondopoga Bay, which was mainly caused by the trout farm impact. At the same time, oligotrophication was observed in the Povenets Bay. The main waterbody of the lake still preserves its high water quality; however, the tendency for its eutrophication is evident by the decrease of the rate of mineral nitrogen to total phosphorus.

Hydrogeochemical features of Lake Kotokel

The purpose of this study is to determine the main hydrochemical parameters of Lake Kotokel deep waters, to identify the role of groundwater feeding it, as well as to establish the features of spatial distribution of macro- and microelements in the lake. Field work was carried out during the ice and ice-free seasons. A special sampler was used to take water samples from the bottom of the lake. Water samples were filtered through the filters with a pore size of 0.45 μm at the sampling site. Plastic bottles were used for the water samples for analysis. Polypropylene containers (15 ml) pretreated with 0.1 N nitric acid were used for the water samples for trace elements. The analysis of the macrocomponent composition of water was carried out in a certified Laboratory of Hydrogeology and Geoecology of the Geological Institute of the Siberian Branch of the Russian Academy of Sciences (Ulan-Ude) according to the standard methods intended for fresh and saline waters. Cations (Ca2+, Mg2+, Na+, K+) were determined by atomic absorption, F-, SiO2 – by the colorimetric method, HCO3- , CO32- and Cl- – by the titrimetric method, SO42- – by the turbidimetric method. The analysis of the trace element content was carried out in the Laboratory of Aquatic Microbiology at the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences (Irkutsk) by the method of inductively coupled plasma on Agilent 7500ce quadrupole mass spectrometer. Conducted research made it possible to determine an inhomogeneous chemical composition of lake water associated with the discharge of fissure-vein waters along the faults that bound the depression from the southeast and northeast and intersect the lake water area from the island to the Istok river. The highest content of dissolved substances was recorded in the strait between Monastyrsky island and the western shore of the lake; the maximum values of hydrocarbonate ion and total mineralization were found here. The maximum content of sulfate ion was found in the southern and southeastern parts of the lake. The dispersion in microelement distribution reaches several mathematical orders. The most variable concentration is characteristic of iron, manganese, copper, zinc, lead, phosphorus, molybdenum, tungsten, strontium. Their high contents were found in the lake water within the location of faults of northeast strike. Therefore, the chemical composition of the water of Lake Kotokel is largely formed by fissure-vein waters. This water is discharged along the tectonic faults of the northeastern strike. The research revealed two centers of subaqueous discharge, which are characterized by the formation of two different associations of microelements in the lake water. The composition of microelements in fissure-vein waters is determined by their interaction degrees with rocks.

Origin of modern dolomite in surface lake sediments on the central and western Tibetan Plateau

Modern dolomite was found in the sediments of 20 lakes on the central and western Tibetan Plateau during lake surveys, in August to November of 2012–2015. We analyzed the mineralogy of authigenic carbonates and the chemical composition of lake water to investigate the environmental factors affecting dolomite formation and to determine the mechanisms of dolomite formation. X-ray diffraction analysis suggested that the dolomite content ranged from 3% to 10%, with a mean of 5%, and that the majority of the dolomite in the surface lake sediments was Ca-dolomite. Dolomite formed in a wide range of salinity environments. There was a positive linear relationship between salinity and Mg/Ca ratio, whereas the pH and sulfate (SO42−) concentration are not significantly correlated with Mg/Ca ratio. High Mg/Ca ratio, high salinity, high sulfate concentration, and high pH are important environmental factors in favor of dolomite precipitation. Evaporation and microbial activity are potential mechanisms for dolomite formation in the central and western Tibetan Plateau. The positive relationship between δ18O and δ13C indicates that the dolomite formed in lakes has a long residence time and undergoes continuous evaporation. The crystal morphologies of dolomite were scattered euhedral grains with diameters of 2–10 μm, as well as sub-spherical and spherical grains (<2 μm) which were present either as dispersed crystals or were aggregated into dolomite clusters. Dolomite crystals were identical both in shape and size to those of microbial dolomite previously discovered in modern lake environments and culture experiments. The dolomite precipitation temperature range calculated using the low-temperature microbial equation was close to the measured temperature, further indicating that microbial activity may be involved in dolomite formation. This study provides natural locations with different water salinities and other environmental factors for dolomite precipitation, which has important significance for studying the mechanism of dolomite formation.

Hydrochemical and Isotopic Characteristics of the Lake Balkhash Catchment, Kazakhstan

Lake Balkhash is one of the largest lakes in the world. It is located in arid Central Asia and receives major water from the Ili River, which is an international river flowing across China and Kazakhstan. Hydrochemical and isotopic measurements of waters can provide an improved understanding of hydrogeochemical processes and environmental characteristics, which is useful for water resource management in arid regions. In this study, δD, δ18 O, and major ions in water samples from the Lake Balkhash catchment were analyzed using an integration of mathematical statistics, Piper diagrams, Gibbs model, and principal component analysis (PCA). Water types and main mechanisms controlling the hydrochemistry presented a clear spatial heterogeneity. The chemical composition of lake waters was dominated by SO4-Na and Cl-Na type, whereas river waters were classified as a HCO3-Ca type. The chemical composition downstream of the Ili River evolved from HCO3-Ca to SO4-Na-Cl type. Gibbs model suggested that the main mechanisms controlling the lake water chemistry were evaporation-crystallization processes, and that major ions in the river water were affected by rock-weathering and evaporation processes. The main controlling factors of the water chemistry changed from the upstream to the downstream, and may have related to spatial differences whereby the upstream area experienced higher rainfall and snow melt, and the downstream area experienced relatively higher evaporation. PCA analysis showed that human activities also played an important role in the chemical composition of water sampled from the lake, middle and lower reaches of the Ili River, and other rivers. The isotopic compositions of the lake and river waters varied spatially. In the lake waters, positive isotopic ratios and negative deuterium-excess values indicated that evaporitic enrichment dominated the changes in the isotopic signature of the lake water. In river waters, isotope values located near the global meteoric water line (GMWL) and lower slopes of the regression lines (r=0.91, P<0.001 for Ili River, and r=0.63, P<0.001 for other rivers), were associated with a stronger influence of rainfall and weaker evaporation. Correlation analysis showed that there were significant relationships between isotope values and chemical parameters in the lake water, especially in the eastern area, thus suggesting that extensive evaporation led to simultaneous enrichment of isotopes and ions in the lake water.

Mineralization of rare metals in the lakes of East Kazakhstan

Purpose. Study on the chemical composition of lake waters, salt brines, brine and bottom sediments to identify the mineralization of rare metals and other types of minerals. Methodology. Mass spectrometric studies (mass spectrometer with inductively coupled plasma ICP-MS 7500cx from AgilentTechnologies) for the purpose of high-precision analytical studies on the chemical composition of salt lake water in order to assess the content of rare elements. The use of unmanned aerial vehicles for linking and geometrizing lakes. Findings. Field surveys on the geometrization and linking of lakes were carried out. From the materials obtained with the help of the drone, orthophotoplans were created (with a measurement accuracy of up to 1 centimeter), as well as a digital terrain model and a digital terrain model. A complex of analytical works was carried out using inductively coupled plasma spectrometry. When analyzing the distribution graphs of the absolute content of micro-components in the waters of the lakes of the Delbegeteysky massif, it was found that all samples were enriched with sodium, phosphorus, iron, magnesium and barium. The results of the analyses revealed the predominance of sulfates and chlorides in the composition of the surface waters of most of the water bodies of the Delbegeteysky massif. At the Burabai site, lake waters are characterized by an alkaline reaction of the environment (on average = 8.71). At the same time, the salinity of water bodies varies from 05 to 9 g/dm3. Originality. Large-scale outcrops of granites of the Kalba complex (P1), with which a rare-metal type of mineralization is genetically associated, are known to be on the selected study sites. Quartz-wire-greisen and quartz-wire tin, tin-tungsten and tungsten formations are also widely developed. Considering the large geochemical migration ability of rare alkaline elements in the thickness of loose sediments as a result of intensive geodynamic processes in the East Kazakhstan region, it is possible to assume the possibility of their migration to the upper horizons and accumulation in salt lakes localized within the area of development of granite intrusions of Permian age and associated deep tectonic faults. Practical value. The results of the research can serve as a revival of the rare metal industry in the region, which will allow developing new high-tech industries and creating new jobs in this area. The obtained results can be used for setting up further exploration and operational work on the selected promising areas.

Assessment of natural processes impact on content of heavy metals in water of Lake Onego

«Вестник Санкт-Петербургского университета. Науки о Земле» — научно-теоретический рецензируемый журнал, обобщающий результаты исследований в области геологии, гидрогеологии и геохимии, петрологии и экологии, ландшафтного планирования и геоморфологии, экономической и социальной географии.

Features of the formation of primary production in small lakes of various natural zones in the south of Western Siberia

The territory of the south of Western Siberia is located in several natural, hydrological and climatic zones. Long-term studies (2008-2019) of small lakes in the region, located on the plain from the steppe zone to the taiga zone, as well as in the mountain-forest and mountain-steppe zones, have been carried out. It is shown that the leading role in the formation of primary production in lakes is played by zonal factors, such as the ratio of elements of water and heat balance; the chemical composition of lake waters, etc. The characteristics of productivity and characteristics of small lakes of different hydrological and climatic zones are given.

Factors affecting chemical composition of lake water of specially protected areas in Altai mountains, Russia, based on Multa river basin study

Mass-spectrometry with inductively coupled plasma was applied to determine the dissolved forms of 26 elements in the water of lakes of the Mul’tinskii Basin. Specific features were identified in the formation of water chemistry in the water bodies of high-mountain Altai territories which suffer little anthropogenic impact. Water quality and the effect of natural factors on it were assessed.

Hydrogeochemistry of a small saline lake: Assessing the groundwater inflow using environmental isotopic tracers (Laguna del Plata, Mar Chiquita system, Argentina)

Major ion and stable isotopic compositions of a saline lake linked to the SW margin of Laguna Mar Chiquita, Argentina (30°55′ S, 62°51′ W) were studied. The groundwater inflow into the Laguna del Plata was quantified for the first time using a stable isotope mass balance. Shallow groundwater inflow is expected in the Laguna Mar Chiquita system since it represents the terminal water body of the catchment. Lake waters are alkaline and exhibit total dissolved solids contents >30 g L−1. The cationic relative abundance is Na+ ≫ Mg2+ > Ca2+ > K+, whereas that of major anions is Cl− ≫ SO42− > HCO3− + CO32−, which are mainly present as free aqueous ions. PHREEQC simulations indicate that lake waters are oversaturated in Ca2+ and Mg2+ carbonates (calcite, huntite, aragonite, dolomite, magnesite), which are expected to be the first minerals to precipitate due to evaporation processes. The main tributary of the lake (Suquía River) and the phreatic aquifer exhibit δ18O and δ2H values consistent with the isotopic signature of rainfall, whereas lake waters define an evaporation line (δ2H (‰) = 5.4 δ18O (‰) + 1.8). The confined aquifer shows a more depleted isotopic composition, reflecting an allochthonous recharge from the mountain ranges (Sierras Pampeanas). The δ18O mass balance indicates a groundwater inflow of ~4.7 m year−1 to the lake, confirming the hydrological conceptual model for the catchment. However, the groundwater contributions do not affect the chemical composition of lake waters, which mainly results from the evaporation processes as shown by the Spencer diagram.

Influence of emission from copper–nickel smelters on the chemical composition of lake water: Acidification forecast

The influence of the emission of sulfur dioxide and solid substances from Pechenganickel and Severonickel copper–nickel combines (Murmansk oblast) on the chemical compositions of lake water and the development of acidification is analyzed. The temporal dynamics of ∼100 lakes, studied in 1990, 1995, 2000, 2005, 2009, and the response of the chemical composition of the lake water to the impact of acid-forming substances depending on the load level (the distance of combines), geologically controlled sensitivity of catchment areas of the lakes studied to acid deposition, and the lake areas is discussed. The likely further changes in sulfate concentration and pH value in the lake water under the scenarios of increase/decrease of sulfur dioxide emissions from smelter are estimated.

Character of spatiotemporal variations in the chemical composition of lake water under the influence of emission from copper–nickel plants: Prediction of acidification

In this paper, we analyze the influence of variations in the emission of sulfur dioxide and solid substances by the Pechenganikel and Severonikel copper–nickel plants in Murmansk oblast on the chemical composition of lake water and development of acidification. The dynamics of ~100 lakes examined in 1990, 1995, 2000, 2005, and 2009 and response of the chemical composition of the lake waters on the impact of acidifying substances was explored depending on the magnitude of load (distance from the plants), geologically controlled vulnerability of the lake catchments to acid precipitation, and the size of the lakes. Possible further changes in the sulfate concentration and pH values of lake waters were estimated for scenarios assuming an increase or a decrease in sulfur dioxide emission from the plants. It was shown that, in the zone of maximum and high load, a 20% change in sulfur dioxide emission will result in a mean change in sulfate concentration of ±8 μeq/L (which is comparable with the regional background) and a change in pH value of ±0.1 in acid-sensitive lakes and will have almost no effect on these parameters in lakes insensitive to acid precipitation.

Features of the formation of chemical composition of lake waters along the eastern shores of Baikal

Features of the formation of chemical composition of lake waters along the eastern shores of Baikal

Geochemical factors for endogenic mineral formation in the bottom sediments of the Tazheran lakes (Baikal area)

We studied recent sedimentation in small saline and brackish lakes located in the Ol’khon region (western Baikal area) with arid and semiarid climate. The lakes belong to the Tazheran system; it is a series of compactly located closed shallow lakes, with a limited catchment area and different mineralization, under the same landscape, climatic, geologic, and geochemical conditions. Two complementary approaches are applied in the research: (1) a detailed study of individual lake and (2) a comparison of the entire series of lakes, which can be considered a natural model for studying the relationship between endogenic mineral formation and the geochemistry of lake waters. The lake waters and bottom sediments were studied by a set of modern methods of geochemistry, mineralogy, and crystal chemistry. The mineral component of the bottom sediments was analyzed by powder X-ray diffraction (XRD), IR spectroscopy, and electron microscopy. The lakes are characterized by predominant carbonate sedimentation; authigenic pyrite, smectite, chlorite, and illite are detected in assemblage with carbonate minerals in the bottom sediments. Carbonate phases have been identified, and their proportions have been determined in the samples by decomposition of the complex XRD profiles of carbonate minerals into peaks using the Pearson VII function. Mathematical modeling of the XRD profiles of carbonates has revealed that predominantly Mg-calcites with variable Mg content and excess-Ca dolomite accumulate in lake bottom sediments influenced by biogenic processes. Aragonite, monohydrocalcite, and rhodochrosite form in some lakes along with carbonates of the calcite-dolomite series. We show a dependence of the composition of the assemblages of the newly formed endogenic carbonate minerals and their crystallochemical characteristics on the chemical composition of lake waters.

Spatial variation of the chemical composition of lake waters in the Tatra National Park

Abstract The aim of this study is to determine the factors affecting the spatial variation of the chemical composition of lake waters in the Tatra Mountains. In most cases, the lake waters are acidic and very dilute, with a low ionic content and low conductivity values. In general, HCO3 - is the predominant anion and Ca2+ is the predominant cation in the chemical composition of the analysed water samples. Among nutrients, NO3 - is the dominant form of nitrogen, but also NH4 + may be found in lake waters. By using principal component analysis (PCA) two factors have been identified that explain 63.6% of the variation in the chemical composition of water. Factor 1, which explains 43.2% of the total variability, is associated with Ca2+, SO4 2-, HCO3 -, Na+, pH and lake area and is related to weathering and atmospheric deposition. Factor 2 explains 20.4% of the total variability and is associated with Mg2+, K+, Cl- and with lake altitude. In terms of chemical composition, based on the projection of cases of the first and second factor, the lakes in the Tatra Mountains may be divided into four groups, representing the following: lakes situated within the subalpine forest at the lowest altitude (&lt;1300 m a.s.l.), characterized by medium mineralization (~14 mg dm-3) and the highest concentration of NH4 + and Cl- (Group I, 8 lakes); slightly alkaline lakes, with the lowest average acidification, medium mineralization (~31 mg dm-3) and the highest concentrations of Ca2+, Mg2+, Na+, K+, HCO3 -, SO4 2-, and low concentrations of NO3 - (Group II, 2 lakes); small lakes (&lt;0.01 ha) located within the alpine meadow and the nival zones at high elevations with the lowest mean mineralization (~4.3 mg dm-3), with the highest ammonium contribution to the sum of ions among all lakes and the largest sensitivity to acidification (Group III, 13 lakes); large lakes with high mineralization and slightly acidic pH (Group IV, 26 lakes) and medium mineralization (~31 mg dm-3).

Specific Features of Forming of Chemical Composition of Lake Waters in Chita-Ingoda Depression (east Transbaikalia)

Numerous lakes of continental type are widespread on territory of Transbaikalia. Chloride and carbonate salts of natrium prevail in chemical composition of lacustrine waters, but water contains only small amount of sulfates. The salinization of river waters due to evaporation provides the accumulation of chloride and carbonate salts of natrium, as well as sulfates. But their concentration in lakes is growing unevenly, because biogeochemical processes, in particular, sulphate reducing processes, influence forming of chemical composition of waters. Sulphate reducing processes take place not only in the bottom sediments, but in the waters of lakes.

Recharge sources and chemical composition types of groundwater and lake in the Badain Jaran Desert, northwestern China

Based on the analysis of ion chemical composition of lake water and shallow groundwater in the Badain Jaran Desert, this paper discussed the characteristics of ion chemical composition, spatial variation of lake water, and possible supply sources of lake water and groundwater in the desert areas. The results show that the pH, salinity, TDS and electrical conductivity of the lake water are greater than those of groundwater. The ion contents of water samples are dominated by Na+ and Cl−. Most of the higher salinity lakes are Na (K)-Cl-(SO4) type, and a few of low salinity lakes belong to the Na-(Mg)-(Ca)-Cl-(SO4)-(HCO3) type. Most of the groundwater is Na-(Ca)-(Mg)-Cl-(SO4)-(HCO3) type, attributed to subsaline lake, and only a few present the Na-Cl-SO4 type, flowing under saline lake. The pH, salinity, TDS and electrical conductivity in the southeastern lakes are relatively low, and there are slightly alkaline lakes. The pH, salinity, TDS and electrical conductivity in the northern lakes are much greater than those of the southeastern lakes, and the northern lakes are moderately alkaline and saline ones. In the southeastern part of the Badain Jaran Desert, the ion chemical characteristics of the lake water from south to north show a changing trend of subsaline →saline→hypersaline. The changing trend of chemical compositions of ions in recent 9 years indicates that most of the ion contents have a shade of reduction in Boritaolegai, Badain, Nuoertu and Huhejilin lakes, which state clearly that the amount of fresh water supply is increasing in the 9-year period. The ion chemical composition of the lake water reveals that the flow direction of lake water is from southeast to northwest in the Badain Jaran Desert. The ion chemical composition, moisture content of sand layer water level height and hierarchical cluster analysis of the lake water and groundwater demonstrate that the lake water is mainly supplied by local rainfall and infiltration of precipitation in Yabulai Mountains and Heishantou Mountain, and the supply from the Qilian Mountains is almost impossible.

Physicochemical simulation of the evolution of small lakes in a cold climate

The paper presents a generalized algorithm for the simulation of multiyear cycles in variations of the chemical composition of lake waters with regard for the seasonal specifics of hydrogeochemical processes. Data were obtained on the behavior of the hydrogeological system during a time span of 500–1000 years. Each of the simulated model cycles involved a successively alternating “summer-winter” time periods. Terrestrial exchange fluxes between reservoirs, groundwater inflow, falls of atmospheric precipitate, and the evaporation of lake water were taken into account for summer periods, whereas winter conditions were simulated as corresponding to the development of the ice phase, the absence of water exchange fluxes, a change from oxidizing to reducing conditions, and the burial of solid phases in the sediments. The results of our physicochemical simulations with the use of data on the composition of natural hydrogeological systems are in good agreement with natural observations and make it possible to realistically predict the evolution of small lakes in the Ol’khon area.