Lake Baikal Water Research Articles

Alkaline Phosphatase Activity and Phosphatase-Active Bacteria in Lake Baikal Water Column and Major Tributaries

Phosphorus is one of the major biogenic elements. Its inflow facilitates eutrophication of lake water. In aquatic ecosystems, phosphorus is present mostly in organic compounds. Ability of aquatic microorganisms to assimilate phosphorus from organophosphorous compounds results from activity of alkaline phosphatases; activity of these enzymes may be an indicator of the state of the ecosystem, phosphate load, and water quality. In the present work, alkaline phosphatase activity (APA) and abundance of phosphatase-active bacteria (PAB) in Lake Baikal pelagic zone and in the mouths of its major tributaries was studied. In the pelagic zone, APA and PAB abundance decreased with depth, indicating that the main processes of phosphate generation occurred in the trophic layer of the lake. In the main tributaries, both APA and PAB abundance were considerably higher than in the pelagic zone. These results indicate active biochemical processes of transformation of organophosphorous compounds occur in the estuarine zones of the rivers. The degradation processes result in regeneration of phosphates, which are completely incorporated in the biological turnover, providing for phytoplankton development.

The Variation in the Water Level of Lake Baikal and Its Relationship with the Inflow and Outflow

Lake Baikal is the largest freshwater lake in the world, accounting for about 20% of the world’s fresh surface water. The lake’s outflow to the ocean occurs only via the Angara River, which has several hydroelectric power plants (HPPs) along its watercourse. The first such HPP, Irkutsk HPP, was built in 1956 and is located 60 km from the Angara River’s source. After two years, the backwater from this HPP expanded to the lake shores and began raising the Baikal Lake level. Currently, there is a dynamic balance between the new lake level, the lake inflow from its tributaries, and the Angara River discharge through the Irkutsk HPP. However, both the Angara River discharge and the Baikal Lake level were distorted by the HPP construction. Thus, to understand the changes to the lake basin over the past century, we first needed to estimate naturalized lake levels that would be if no HPP was ever built. This was an important task that allowed (a) the actual impact of global changes on the regional hydrological processes to be estimated and (b) better management of the HPP itself to be provided through future changes. With these objectives in mind, we accumulated multi-year data on the observed levels of Lake Baikal, and components of its water budget (discharge of main tributaries and the Angara River, precipitation, and evaporation). Thereafter, we assessed the temporal patterns and degree of coupling of multi-year and intra-annual changes in the lake’s monthly, seasonal, and annual characteristics. The reconstruction of the average monthly levels of Lake Baikal and the Angara River water discharge after the construction of the Irkutsk HPP was based on the relationship of the fluctuations with the components of the Lake water budget before regulation. As a result, 123-year time series of “conditionally natural” levels of Lake Baikal and the Angara River discharge were reconstructed and statistically analyzed. Our results indicated high inertia in the fluctuations in the lake level. Additionally, we found a century-long tendency of increases in the lake level of about 15 cm per 100 years, and we quantified the low-frequency changes in Lake Baikal’s water levels, the discharge of the Angara River, and the main lake tributaries. An assessment of the impact of the Irkutsk HPP on the multi-year and intra-annual changes in the Lake Baikal water level and the Angara River discharge showed that the restrictions on the discharge through the HPP and the legislative limitations of the Lake Baikal level regime have considerably limited the fluctuations in the lake level. These fluctuations can lead to regulation violations and adverse regimes during low-water or high-water periods.

Search for putative complete and near-complete genomes of DNA-containing viruses in metagenomes obtained from the Lake Baikal

The paper presents the analysis of putatively complete and near-complete genomes of bacteriophages extracted from metagenomic data obtained from DNA samples isolated from Lake Baikal water using modern bioinformatic programs. A total of 73 sequences with lengths ranging from 13.8 kb to 163.7 kb belonging to phages of the Caudoviricetes class were identified. Two contigs belonging putatively to cyanophages with lengths of 36.8 kb and 163.7 kb were detected, and in the latter one an ORF with a length of 159 amino acid residues similar to the small heat shock protein (Hsp20) was identified. Analysis of the amino acid sequences identified in the assembled bacteriophage genomes using the PHROG database revealed that 27.5% of them have an unknown function, while the majority of those with similarity to known ones (23.7%) belong to the category “DNA, RNA and nucleotide metabolism”. A number of accessory metabolic genes (AMGs) were also detected in the assembled genomes: nadM, cysC, cobS, galE, cobT, etc. Most of the sequences with similarity to sequences from the IMG/VR database (89.6%) corresponded to sequences obtained from freshwater bodies.

Application of the Pareto Front to Finding Compromise Rules for Lake Baikal Water Level Management

Application of the Pareto Front to Finding Compromise Rules for Lake Baikal Water Level Management

Methane Distribution in Lake Baikal Water

Methane Distribution in Lake Baikal Water

Methane Distribution in Lake Baikal Water

Data on the distribution of methane concentration in water in the open water area and the northern end of Lake Baikal and in the source of the Angara R. collected in September 2016 and 2019 are analyzed. To apply correlation analysis, in addition to methane, various hydrochemical characteristics were also determined, including the temperature, pH, the concentrations of О2, suspended matter, Corg, Norg, Porg, mineral compounds of nitrogen and phosphorus. Methane concentration in Baikal water in 2016 varied within 0.44–3.41 µL/dm3 (on the average, 0.80 µL/dm3); in 2019, within 0.20–5.19 µL/dm3 (on the average, 1.22 µL/dm3). The maximal methane concentration was recorded in the water mass of the deepest central depression of the lake, and the minimal, in its southern depression. Among shallow areas, minimal methane concentrations were recorded in the coastal zone of Listvenichnyi Bay, and its maximal concentrations, in the northern part of the lake, into which many rivers empty, as well as in Selenginskoe shallows. Most stations, either deep-water or shallow, showed a peak of subsurface maximum of methane concentration at depths of 25–50 m (thermocline zone), after which its concentrations commonly dropped, reaching their minimal values either in the intermediate water mass or in bottom layers. Shallow areas, in addition to higher methane concentrations compared to deep-water areas, also featured a higher contrast in its vertical distribution in the water mass. The analysis of correlation relationships between the examined hydrochemical characteristics revealed significant direct correlations of methane concentration with the concentrations of Corg and Norg and an inverse correlation with O2 concentrations.

Uranium in man-made carbonates on the territory of Ufa

The paper presents the results of analyzing uranium content in man-made carbonates (scale crusts) on the territory of Ufa based on examination of 42 samples. The median uranium content in the investigated samples stands at 1.44 mg/kg, which is significantly lower than the background values (scales from the Lake Baikal water, a clarke of sedimentary carbonate rocks) and data on other settlements of the Republic of Bashkortostan. Low values of uranium content are probably associated with the effects of the three leading factors, i.e. specific subsurface geology of the territory (gypsum, limestone); types of water supply; water treatment processes for the centralized type of water supply. Spatial distribution of uranium in man-made carbonates is characterized with uniformity, which is disturbed in two cases, i.e. a change of the water supply type (from centralized to individual); and material of the vessels used for boiling the water. No significant differences were detected when comparing samples of man-made carbonates associated with different sources of water supply (the bucket and infiltration types of water intake) and the types of household filters.

Climate change and its effects on the water level of Lake Baikal region since the 1980s

气候变化对湖泊水位的影响是湖泊研究的关注热点.作为欧亚大陆最大淡水湖，贝加尔湖水位变化深受自然因素和人类活动的共同影响.在全球变暖背景下，贝加尔湖水位升降将对维系流域生态系统与社会发展至关重要.为此，基于湖区气象站、水文站和湖泊水位观测数据，采用突变检验、变异系数检验等方法，分析了过去40年贝加尔湖周边气候变化及其对水位的影响.主要结论如下：1980-2019年，贝加尔湖及其周边区域气温整体呈显著上升趋势（0.31℃/10 a），其空间分布主要受纬度和海拔影响；年际降水波动较大（变异系数达0.2左右），但变化趋势不显著，其空间分布主要影响因素为地形.过去40年，贝加尔湖平均水位为456.42 m，水位发生多次大幅波动.1980-2015年，色楞格河和安加拉河径流量总体呈先增加后减少的变化格局，是导致贝加尔湖水位先上升后下降的重要原因.而入湖、出湖径流的高低主要受控于降水的多寡.通径分析结果表明，降水是影响贝加尔湖水位变化的主要气象因素，降水通过直接补给和入湖径流补给共同影响贝加尔湖水位.本文将水位转折的原因大致划分为3类：第1类是气候变化驱动型，指1982-1983、1985-1987和2013-2015年这3个阶段的水位突变过程；第2类是气候变化与人类活动共同驱动型，以1995-1996年水位大幅下降过程为例，气候变化与流域内人类活动共同导致了水位突变；第3种类型是气候变化背景下的人为调控驱动型，这是贝加尔湖特有的水位变化驱动类型，即俄罗斯联邦政府立法通过下游水利枢纽工程人为调控湖泊水位.由于持续的暖干气候条件，贝加尔湖2015-2017年水位被严格控制在456.07 m左右的低水位.本研究将为贝加尔湖未来气候变化预估、后续水位调控以及流域灾害防控提供理论支撑.;The impact of climate change on lakes is one of the lake research foci. As the largest freshwater lake in Eurasia, Lake Baikal is impacted by both the natural environment and human activities. Hence, it is indispensable to discuss how Lake Baikal will change with global warming to guarantee the watershed ecological balance and regional sustainable development. We, therefore, analyzed the climate change in the Lake Baikal region and its impacts on the water surface level of Lake Baikal over the past 40 years, with the coefficient of variation test and multi-methods of abrupt change test using the observation data from meteorological stations, hydrological stations and water level of the lake surface. The main conclusions are summarized as follows. From 1980 to 2019, the annual average temperature around Lake Baikal shows a significant rising trend of 0.31℃/10 a, and its spatial distribution is mainly affected by latitude and altitude. The annual average precipitation fluctuates remarkably with a variation coefficient of about 0.2, and the overall variation trend is not significant. The main controlling factor of its spatial distribution is topography. In the past 40 years, Lake Baikal's average water level is 456.42 m, and the water level has undergone several sharp changes. The runoff in Selenga River and Angara River increases first and then decreases during 1980-2015, leading to the water level changes of Lake Baikal synchronously. The results of path analysis show that precipitation is the main meteorological factor affecting the water level of Lake Baikal. Precipitation affects the water level of Lake Baikal through both direct recharge and runoff recharge. We roughly divide the causes of water level transition into three categories. The first type is the climate change-driven type, which refers to the abrupt changes in water level during 1982-1983, 1985-1987, and 2013-2015. The second type is the combination of climate change and anthropogenic activities. Taking the dramatic decline of water level in 1995-1996 as an example, climate change and the increase of human water use in the basin led to the dramatic shift in water level. The third type is government regulation control with climate change, which is unique to Lake Baikal. That is, the government regulates the water level of the lake artificially through the downstream hydroelectric facilities. Due to the continuous warm and dry climate conditions, Lake Baikal's water level is strictly controlled at a low value of 456.07 m from 2015 to 2017. This study hopefully will provide theoretical support for the projection of climate change, water level control, and disaster prevention of Lake Baikal Basin.

Modeling of shoreline changes and assessment of the influence of Lake Baikal water level fluctuations on settlements along the eastern coast

Modeling of shoreline changes and assessment of the influence of Lake Baikal water level fluctuations on settlements along the eastern coast

Drivers and extent of surface water occurrence in the Selenga River Delta, Russia

Study regionSelenga River Delta (SRD), Russia. Study focusHow is water occurrence changing in the SRD, and what are the hydroclimatic drivers behind these changes? The presence of water on the surface in river deltas is governed by land use, geomorphology, and the flux of water to and from the Delta. We trained an accurate image classification of the Landsat satellite imagery during the last 33 years to quantify surface water occurrence and its changes in the SRD. After comparing our estimations with global-scale datasets, we determined the hydrological drivers of these changes. New hydrological insights for the regionWe find mild decreases in water occurrence in 51% of the SRD's surface area from 1987–2002 to 2003–2020. Water occurrence in the most affected areas decreased by 20% and in the most water-gaining areas increased by 10%. We find a significant relationship between water occurrence and runoff (R2 =0.56) that does not exist between water occurrence and suspended sediment concentration (SSC), Lake Baikal's water level, and potential evapotranspiration. The time series of water occurrence follows the peaks in the runoff but not its long-term trend. However, the extremes in SSC do not influence surface water occurrence (R2 <0.1), although their long-term trends are similar. Contrary to expected, we find that the Delta has a relatively stable long-term water availability for the time being.

Anthropogenic рollution of the coastal zone and hydrochemical analysis of the waters of Lake Baikal within the borders of the Republic of Buryatia

Anthropogenic impact on Lake Baikal is currently a big problem for the world community as a whole. Its solution depends on a number of factors, the main of which is the assessment of the level of impact and its maximum reduction. According to various researchers, a gradual accumulation of a number of chemical elements occurs in the waters of Lake Baikal, which leads to a change in the ecosystem as a whole. The purpose of this work was to assess the state of the coastal zone and to assess the hydrochemical regime of the coastal zone of the northeastern coast of Lake Baikal. According to the results of the observations, the coastal zone of Maximikha and Oymur villages is the most polluted, where a large amount of rotting algae was observed, as well as anthropogenic pollution. The least polluted is the coastline about c. Ust-Barguzin. According to the results of the study of physical indicators of Lake Baikal water, the achievement of the upper limit of the MPC in terms of color in the water samples of the Dulan ulus in the summer of 2020 and in the spring of 2021, as well as in the spring in the water samples of the village of Sukhaya was found. In addition, the turbidity index of the water near the Dulan ulus in the spring period was 2 EMF, which is also on the border of the norm. According to the results of the study of chemical parameters of water, the pH at most points is slightly alkaline, the water hardness at all stations did not exceed 3°. The total alkalinity of water at all stations ranged from 92.8 to 23.2 mg-eq/dm³. The ion content of various substances does not exceed the values established by other authors for oz. Baikal is: dissolved oxygen (O₂) — from 6 to 12 mg/dm³, chlorine ions (CL⁻) — from 0.1 to 0.5 mg/dm³. The value of permanganate oxidizability is 2 mg/dm³.

Lake Baikal highstand during MIS 3 recorded by palaeo‐shorelines on Bolshoi Ushkanii Island

The debate regarding the history of water‐level fluctuations in Lake Baikal extends back to the late 19th century and is rooted in the interpretation of the sequence of palaeo‐shoreline terraces observed around the Baikal trough. Modern studies identify terraces up to 200 m above and down to 40 m below the present‐day Lake Baikal water level, and opinions are split between (i) those who regard the lake‐level fluctuations as a function of shifts in water balance associated with glacial and interglacial periods, and (ii) those who attribute the changes to predominantly tectonic factors, permitting water‐balance fluctuations of not more than a few tens of metres. In either case, a definitive lake‐level scheme must also constrain the relative elevation of the Baikal's outlet, which has not been fixed over time. Here, we focus upon the lake‐level changes over the past 50 000 years with a new set of observations from an outstanding sequence of palaeo‐shoreline terraces on Bolshoi Ushkanii Island located in central Lake Baikal. By determining the 14C age of soils rapidly buried by beach deposits on two terraces, we provide direct evidence of lake‐level highstands at ~120–122 and ~72–83 m during Marine Isotope Stage (MIS) 3 (Karginsk interstadial). By integrating these results with the repeated subsidence of Baikal's outlet threshold since MIS 5e, we show that lake‐level fluctuations closely align with swings in glacial and interglacial climate.

SIMULATION OF WINTER CIRCULATION OF THE ATMOSPHERE OVER THE BAIKAL REGION

In order to assess the influence of sources of pollutants on the atmosphere of the Lake Baikal water area, the ICMMG SB RAS model is adapted to the geographical and climatic conditions of the Baikal region. Two scenario calculations describing the characteristic circulation of the winter atmosphere in conditions when Lake Baikal is covered with ice and those in the presence of an open water surface were performed. Some variants of passive impurity transfer from Irkutsk by the North-West wind flow simulated in these scenarios are discussed. With the same large-scale input data, the impurity concentrations reaching the lake's water area were lower in the scenario with frozen Lake Baikal surface. A preliminary comparison of the results of calculations has shown that the influence of differences in the thermal properties of the surface of Lake Baikal in these scenarios is manifested in the atmosphere of the surrounding territory at distances of the order of the width of the lake.

Historical floods within the Selenga river basin: chronology and extreme events

Large floods are among the most hazardous natural phenomena, which in many cases cause enormous losses to the economy and lead to human casualties. Along with the use of modern instrumental data, the analysis of historical information on large past floods is widely practiced in the world. This allows obtaining qualitative and quantitative characteristics of historical floods and significantly expanding the observation series. The Selenga River is one of the largest rivers of Central Asia with catchment area equal to 447,060 km2, and also it is rather flood-prone river. The hydrological regime of the Selenga River is quite well studied in the twentieth century on the basis of gauging stations data, but there is still a lack of knowledge about past floods. In this paper, we present a list of 26 known floods within the Selenga River basin from 1730 to 1900, compiled from available historical documents (newspapers, scientific reports, diaries, memoirs, etc.). We estimated peak water levels for three catastrophic floods (1830, 1869 and 1897), the historical maximum of which was 850 cm. The reliability of our estimates is confirmed by a comparative analysis of the large 1971 flood. It was revealed that the largest floods can cause a rise of the Lake Baikal water level up to 200 cm. The inflow to Lake Baikal resulting from the largest floods in the Selenga River basin is comparable to the average annual inflow of water into the lake. We can conclude that the use of historical data for the analysis of floods in Eastern Siberia is quite acceptable, but some limitations must be taken into account.

Effects of Climatic Warming and Wildfires on Recent Vegetation Changes in the Lake Baikal Basin

The vegetation changes in the area of the Russian part of the Lake Baikal water basin for the period 2010–2018 were investigated using MCD12C1 land cover. The decline in swamp systems area began in 2012 and continued until 2015, after which it partially recovered during the heavy rain season in 2018. During the period of 2010–2018, the area covered by forests did not exceed 20.3% of the Baikal basin of the total portion of the Baikal basin under study. Deforestation began in 2013 and continued until 2017. Over 2013–2018, the forest level decreased by 12.1% compared to the forest state in 2013. The analysis of summer rainfalls and aridity indexes was performed by using CRU TS and GPCC climatic datasets. It is shown that the interannual variations of precipitation and aridity changes are determined by the variability of the global circulation of moist air masses. The MCD64A1 (burned area) and MCD14ML (active fires) MODIS products were used for investigation of the influence of wildfires on vegetation changes. The spatial hotspot distributions and burned areas in general correspond to aridity zones, but they cannot explain the 20-fold increase in the number of wildfires. Most of the hotspot locations are away from settlements, roads, and loggings, in difficult-to-access mountainous areas, as well as in the low-inhabited areas of Siberia. We assume that the nature of such ignitions includes dry thunderstorms, pyrocumulus lightning, or remote impact.

Genetic diversity of Actinobacteria inhabiting water and sponges of Lake Baikal

Actinobacteria is a ubiquitous major group in freshwater bacterioplankton and sponge microbial communities. We were first to analyse the diversity of Actinobacteria inhabiting Lake Baikal water and endemic sponges Lubomirskia baikalensis (healthy and diseased) using highthroughput 16S rRNA sequencing. In total, we have assigned of three classes, fourteen orders and twenty-six families of Actinobacteria. The diversity and composition of actinobacteria were common in bacterioplankton and healthy sponges. The environmental crisis in the coastal zone of Lake Baikal led to a colonization of the L. baikalensis by benthic and soil-derived representatives of Actinobacteria. Some amplicon sequences of opportunistic genera were detected in the coastal water. The example of Actinobacteria has dramatically demonstrated the response of bacterial populations caused by negative environmental impact.

Methane hydrate emergence from Lake Baikal: direct observations, modelling, and hydrate footprints in seasonal ice cover

This paper provides a novel report of methane hydrates rising from bottom sediments to the surface of Lake Baikal, validated by photo and video records. The ascent of hydrates in the water column was confirmed by hydroacoustic data showing rising objects with velocities significantly exceeding the typical speeds (18–25 cm s−1) of gas bubbles. Mathematical modelling along with velocity and depth estimates of the presumed methane hydrates coincided with values observed from echograms. Modelling results also showed that a methane hydrate fragment with initial radius of 2.5 cm or greater could reach the surface of Lake Baikal given summer water column temperature conditions. Results further show that while methane bubbles released from the deep sedimentary reservoir would dissolve in the Lake Baikal water column, transport in hydrate form is not only viable but may represent a previously overlooked source of surface methane with subsequent emissions to the atmosphere. Methane hydrates captured within the ice cover may also cause the formation of unique ice structures and morphologies observed around Lake Baikal. Sampling of these ice structures detected methane content that exceeded concentrations measured in surrounding ice and from the atmosphere demonstrating a link with the methane transport processes described here.

Level Regime of Lake Baikal: Problems and Contradictions

We examine the current problems of Lake Baikal level regulation. A comparative analysis is made of the changes in the lake level, the range of its fluctuations and in the intra-annual amplitude for the 120-year-long period of observations in natural and regulated conditions. The period 2014–2017 with an extremely low water level is analyzed. It is pointed out that the inconsistency between existing legislation and the water resource management system within the Baikal and Angara drainage basins has also contributed to the decline in sustainability of the water economy, along with the climatic factors. It was found that while generally quite well complying with the requirements of water users and water consumers in conditions of normal and almost normal water availability, it cannot meet the regulatory needs and restrictions in periods of extreme water availability. The risks and contradictions in the regulation of the Lake Baikal water level in low- and high-water years are considered. Quantitative assessments are made of the possible maximum levels in Lake Baikal during floods for different restrictions of water flow in the downstream water. The estimates of expected areas of flooding are given. It is pointed out that along with water management and socio-economic risks, climatic and environmental factors should also be taken into account in the lake level regulation. An analysis is made of the environmental requirements which were taken into account when setting the limited meter range of Lake Baikal level regulation (Decree of the Government of the Russian Federation of 3.26.2001 No. 234). There is an inconsistency in these requirements and, in some cases, the impossibility of meeting them. Quantitative assessments are made of the implications of the re-enforcement of Decree No. 234 on January 1, 2021. It is shown that the enforcement of this decree in full necessarily involves violating the requirements of water users. The years of elevated water levels are necessarily accompanied by flooding of the city of Irkutsk. It is suggested that the “social” option of regulating the level of Lake Baikal water level regulation be used in order to avoid infringement of existing legislation and flooding by the downstream water. Special research work should be done to determine a reasonable range of Lake Baikal water level regulation having regard to the current environmental and socio-economic factors.

Metals in the Waters of the Southern Tributaries of Lake Baikal

We examine the composition of metals in the waters of the southern tributaries of Lake Baikal as well as comparing it with the composition of metals in bottom sediments and calculating the water migration coefficients of metals. The territory of the southern part of the lake drainage basin was regionalized according to the ability to ensure a particular water composition. The contribution from the southern tributaries to the chemical composition of Lake Baikal water was evaluated. It was found that the composition of macroelements and trace elements in the waters varies over a broad range. There occur waters with salt contents far exceeding those in Baikal water and its main tributaries as well as with considerably lower salt contents. Macroelements in the waters of all the streams studied are absolutely dominated by calcium, whereas the waters differ greatly in magnesium and sodium contents. Trace elements in the waters of the rivers on the southwestern coast are dominated by strontium, vanadium and molybdenum, which significantly differs them from the waters of the rivers of the southeastern coast, Lake Baikal and its main tributaries. The values of the water migration coefficients as calculated for the macroelements in the waters of the southern and main tributaries of Baikal are similar. The water migration coefficient of trace elements for the river waters in the study area differ greatly from the coefficients for the waters of the main tributaries of Baikal. The reason behind this is the existence of sources of dissolved matter, such as rocks and deep underground water, with their composition not characteristic for corresponding landscapes. The contribution from the southern tributaries to the macroelement composition of Lake Baikal waters can be estimated at the range of 5 to 30% depending on the selected tracer metals. The contribution from the southern tributaries to the trace element composition of the Baikal waters defies estimation because of their much higher concentrations in the rivers when compared with Baikal water. The differences in the trace element concentrations in the water of Baikal water and of its tributaries are caused by their migration in the composition of organic matter. In consequence of a long period of water exchange in Baikal, this matter is deposited or decays thus promoting the removal of trace elements from solution.

Metals composition of the surface waters of the Southern Baikal region and its connection with landscape and geological conditions

The metal composition of water and bottom sediments of southern Lake Baikal tributaries was studied and the water migration coefficients for micro- and trace elements were calculated. The map showing the study area divided into zones according to their ability to provide the certain water quality was drawn. The significant differences in mineralization, macro- and trace element composition between Lake Baikal water and tributary waters were found out. It was shown that values of water migration coefficients calculated for macro elements are similar in southern and main tributaries whereas coefficient values calculated for trace elements are quite different. This is due to dissolved matter sources such as rocks and deep ground waters which chemical composition is not typical for landscapes of Lake Baikal basin. The contribution of southern tributaries to macro element composition of lake water is between 7 and 15%, whereas tributaries contribution to trace element composition can hardly be evaluated because of higher element concentrations in riverine waters. The lower trace element concentrations in lake water with respect to riverine one is due to trace element migration in the form of complex organic compounds: long water residence time in lake favors to organic compounds decay by means of microbial- and photo-degradation followed by metal precipitation.