Barguzin Bay Research Articles

Features of changes in the concentrations of nutrients and plankton at the thermal bar: A numerical experiment

On the example of Barguzin Bay of Lake Baikal, mathematical modeling of the dynamics of nutrients and plankton during the development of the spring thermal bar was carried out. The meteorological data of the Ust-Barguzin station for June 2023 were set in the calculations. An analysis of the horizontal movement of the area of the maximum density temperature at the lake surface was carried out, the features of changes in the concentration of nitrates, ammonium, phosphates, dissolved oxygen, as well as phyto- and zooplankton in this area are described.

Гидроакустическая оценка запасов байкальского омуля (Coregonus migratorius) по результатам двухлетних исследований в весенне-летний период 2021 и 2022 годов

Taking into account the depressive condition of the Baikal omul resource, the decree of the Ministry of Agriculture of the Russian Federation No. 450 dated August 29, 2017 strict restrictions were established on the catch of Baikal omul in order to restore its reserves. Since 2021, a hydroacoustic method based on hydroacoustic surveys has been used to estimate its recovery. In 2021, on the fishing areas of Lake Baikal (Selenga shallow water and Northern Baikal) there were conducted surveys. In 2022, in addition to these areas, the researches were conducted in the Barguzin Bay and the Small Sea. Significant increase in the number of small omul was observed in the Selenginsky shallow water area in 2022. The results of a comparative analysis on Northern Baikal within the water area of 2021 showed that, taking into account confidence intervals, the number of omul and its biomass practically did not change. The averages omul biomass and number per unit area in the Small Sea were significantly lower than in the waters of the Selenginsky shallow water and the Northern Baikal. The lowest average densities were recorded in the Barguzin Bay.

On the role of wind direction in the thermal bar dynamics in autumn: A numerical study

The effect of wind direction on the dynamics of the thermal bar in autumn was studied in Barguzin Bay of Lake Baikal by numerical modeling. An analysis of the temperature fields simulated showed that wind direction was essential to thermal bar development and temperature distribution. Easterly wind, in contrast to westerly wind, contributed to increased speed of the surface propagation of the thermal bar toward the open lake. The results presented here also demonstrate that autumnal cooling of Barguzin Bay was faster during easterly wind activity.

Results of resource hydroacoustic surveys of the Baikal omul in the fishing waters of Lake Baikal in the spring-summer period of 2022

The purpose of the work carried out is to quantify the abundance of the Baikal omul within the four fishing areas of Lake Baikal (Selenginsky shallow water, Northern Baikal, the Small Sea, Barguzin Bay), to build maps of the spatial distribution of fish concentrations in the surveyed waters.The data collection and processing method is based on hydroacoustic survey, during which echo signals are recorded in the vertical direction along the route of the ship along a pre-planned transects. To calculate the values of surface densities along the survey transects, the echo integration method was used. When calculating surface density values, data from control catches are used. The Kriging geostatistical interpolator was used to numerically estimate the stocks of omul and its distribution within the surveyed water areas.New data have showed that in the main fishing area of Lake Baikal, the Selenginsky shallow water, there was a high abundance of juvenile omul, less than 22 cm in size of the 2018 generation and younger. In the areas of the Small Sea and the Barguzin Bay, no significant accumulations of fish were recorded. In Northern Baikal, the abundance and biomass of the omul was comparable to the results of 2021.The practical significance of the research results is the quantitative assessment of the omul stocks and its distribution in the fishing areas of Lake Baikal in order to predict its stocks.

Unique and ancestral features in trunk kidney microanatomy and ultrastructure of omul Coregonus migratorius.

This study presents novel data on the microanatomy and ultrastructure of the omul Coregonus migratorius trunk kidney. Adult individuals of C. migratorius were sampled in the Barguzin Bay of Lake Baikal. Active leuko- and erythropoiesis were found in the interstitium of the mesonephros. For the first time, cells with radially arranged vesicles have been described in the renal interstitium of C. migratorius. The quantitative characteristics of blood cells and ultrastructural parameters of leukocytes reflected the functioning of the non-specific defence system in the organism. The share of the renal interstitium, morphological diversity of the epithelial cells of the nephron tubules, the ultrastructural features of the renal corpuscles and nephron tubules and the number of mitochondria in leukocytes and ion-transporting cells were typical for representatives of the whitefish Coregonus lavaretus complex and thus considered ancestral features of the present-day C. migratorius population reflecting its adaptive potential to living in an ultra-deep Lake Baikal.

ПОСТУПЛЕНИЕ БИОГЕННЫХ ЭЛЕМЕНТОВ С ВОДАМИ РЕКИ БАРГУЗИН И ИХ РОЛЬ В ЭВТРОФИРОВАНИИ БАРГУЗИНСКОГО ЗАЛИВА (ОЗЕРО БАЙКАЛ)

The results of multiyear studies of biogenic element concentrations in the Barguzin River mouth and the Barguzin Bay are presented. The key role of the water outflow dynamics in seasonal and interannual changes in concentrations of biogenic elements and organic carbon in the river and their inflow to the bay is confirmed. The spatial distribution of biogenic element concentrations in the bay depends on seasonal hydrological and geophysical conditions and on the activity of phytoplankton development. It is shown that under low-water conditions in the bay, the concentration of mineral compounds of biogenic elements decreased and that of organic compounds increased. In terms of total phosphorus, the Barguzin Bay is mainly characterized as a mesotrophic water body.

Inflow of Biogenic Elements with the Barguzin River Water and Their Role in Eutrophication of the Barguzin Bay (Lake Baikal)

Inflow of Biogenic Elements with the Barguzin River Water and Their Role in Eutrophication of the Barguzin Bay (Lake Baikal)

Modeling biogeochemical processes in a freshwater lake during the spring thermal bar

This article describes a coupled physical–biological model for reproducing the ecological processes in a freshwater lake during the evolution of the thermal bar, a phenomenon of sinking of maximum density waters in a narrow zone. The biological part of the model includes 10 prognostic variables: nitrate, phosphate, ammonium, chlorophyll a, phytoplankton, zooplankton, and nitrate and phosphate detritus of small and large sizes. The results of modeling of hydrodynamic processes in Barguzin Bay of Lake Baikal using meteorological data for June 2019 demonstrate a short-term period of the thermal bar existence. The analysis of spatial distributions of biochemical variables of the model showed that the thermal bar acts as a natural barrier limiting the transfer of phosphates and plankton to the open lake.

Changes in patterns of mineral and chemical elements in bottom sediments of Lake Baikal (Russia) as high-resolution records of moisture for the past 31–16 ka BP

The high-resolution biochemical records (SRXRF, ICP-MS and FTIR analyses) of bottom sediments were used for the reconstruction of clastic flux into Lake Baikal via the Barguzin River as moisture and glacier indexes from 1631 ka BP. According to the obtained data, proxies of a high supply of clastic flux by the river are high: the content of feldspar and LREE/HREE, Rb/Sr and Th/Mo ratios. We sampled a sediment core extremely close to the estuary of the Barguzin River. It seems that the water budget of the Baikal tributaries dramatically reduced ca. 34–30 ka BP, and the lake water level was minimum (less than 35–40 m compared to the present) for the last 34 ka. The lake water level has gradually increased from ca. 30 to 25–23 ka BP, and it was likely linked with the activity of the East Asia Monsoon. The very contrasting changes in chemical and mineralogical records were ca. 29.5 ka BP, and these changes were very likely associated with the Heinrich-3; however, there were no significant changes in the records around the Heinrich-2. Our records revealed some intensification of the clastic flux of the Barguzin River into the Barguzin Bay ca. 25–23 ka BP. The Baikal event ca. 21.5–22.5 ka BP was characterized by a sharp reduction of the influx of clastic material into the Barguzin Bay. The time span of 19.5–18 ka BP was the last time that the Barguzin River inflow increased during the Late Pleistocene. This increase in the water budget was at arid regional conditions, and we assumed it could occur due to the contribution of meltwater from glaciers of the Barguzin Ridge. It is most likely that at the regional Late Pleistocene/Holocene transition (around 12–13 ka BP), a rapid rise of the water budget of the Barguzin River occurred, while the lake level was not high, and the sediments deposited from 12(13)–16.5 ka BP could be directly eroded by a kill of the Barguzin River. In general, the obtained records show that an increase in the water budget of the Barguzin River was gradual. The duration of high inflow into the Barguzin Bay was ca. 1.5 ka, while the reductions of this inflow were dramatic.

GEOELECTRICAL SECTION OF THE BARGUZIN BAY OF LAKE BAIKAL ACCORDING TO GEORADAR AND RADIO IMPEDANCE SOUNDING DATA

Electrical resistivity (electrical conductivity) of water and bottom soil of the Barguzin Bay was studied by radio impedance soundings in VLF/LF bands, and the measurements were analysed. The georadar sounding method was used to investigate dielectric permittivity of freshwater ice (dielectric constant is ε=3.4). We developed the technique of radio impedance sounding from the ice surface of Lake Baikal for measuring the electrical resistance of bottom soil in the water area, and applied this technique to a layered model of a medium with a base showing poor/good conductivity. Geoelectric models were constructed for the Barguzin Bay coast and the southern Lake Baikal. The geoelectrical section (GES) of the water area can be useful for earthquake forecasting from electromagnetic data, as well as for analysing the physical and chemical causes of the occurrence of ring structures on the ice surface of Lake Baikal.

Water Chemistry in Small Tributaries and the Coastal Zone of Lake Baikal in the Period of Environmental Crisis

In the context of the environmental crisis observed in recent years in some areas in Baikal coastal zone, water chemistry was studied in June 2018 in seven points in this zone at different distances from populated localities and in six small tributaries of the lake. To compare data on different biological seasons lake water sampling was repeated in August–September 2019 in four previous and five additional points. Water mineralization was found to be minimal in the southern Baikal. The total mineralization of Baikal water remained relatively low, not exceeding the background values in previous decades; the concentration of environmentally hazardous elements is also low, except for the higher concentration of strontium in the thermal water of the Goryachinskii Creek. On the other hand, Baikal water in most points showed higher nitrogen content, and anomalously high phosphate concentration (0.413–0.941 mg/L) was recorded in the middle part of the lake (Barguzin Bay at Maksimikha Settl., at Svyatoi Nos Peninsula, and at Bol’shoi Ushkanii Isl.). Considerable enrichment of Baikal water by nutrients, which can provoke extremely high values of alga biomass in late summer and early autumn, was recorded not only near populated localities but also far from them and was not caused by inflow of these elements from tributaries. The sources of these pollutants are to be identified. In the late August–early September 2019, in the period of active consumption of phosphorus by summer phytoplankton and bottom algae, the concentration of phosphates in Middle Baikal decreased, remaining elevated (0.09 mg/L) near Maksimikha, but it abruptly rose (1.33 mg/L) in the thermal Goryachinskii Creek. In that period, water near Slyudyanka City (the southern part of the lake) was rich in nitrates (1.67–1.94 mg/L); their concentration was highest near Maksimikha (2.39 mg/L). The high concentration of nutrients in Baikal water requires extensive comprehensive measures to be taken to reduce the anthropogenic load onto lake ecosystem.

Dynamics of nutrient concentrations and eutrophication of the waters in Barguzin Bay (Lake Baikal)

We present the results of long-term studies of the nutrient concentrations in the Barguzin River and Barguzin Bay. The bay has specifics in the spatial distribution as well as seasonal and interannual dynamics of the nutrient concentrations. In the interannual aspect, the concentrations of mineral forms of nutrients decreased in the bay. Based on the total phosphorus concentration, the water in Barguzin Bay is classified as slightly polluted.

Water quality in the littoral zone of the Barguzin and Chivyrkuy bays in the summer of 2019

Currently, with an increase in technological progress, anthropogenic impact on the environment is increasingly apparent. Since surface waters are the most vulnerable part of the natural environment, a detailed study of water pollution is one of the urgent tasks. This article presents the results of the instrumental measurements and the assessment of the pollution of the surface waters in the littoral zone of the Barguzin and Chivyrkuy bays of Lake Baikal. To determine the degree of water pollution, we compared hydrochemical indicators with the standards of the maximum permissible concentrations. We revealed that in different parts of the Chivyrkuy Bay, water quality varies in a wide range from slightly polluted to very polluted and, in some cases, highly polluted. The waters in the Barguzin Bay can mainly be classified as slightly polluted, and only in some areas – as moderately polluted or highly polluted. According to the comprehensive water pollution index, the waters in the Chivyrkuy and Barguzin bays is assessed as conditionally polluted and conditionally pure, respectively.

Features of the spatial distribution of gaseous impurities in the atmosphere of the South-Eastern coast of Lake Baikal by route measurements in the summer period 2018-2019

The paper presents the results of route measurements of concentrations of sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2) in the atmosphere of the coastal zone of Lake Baikal in summer by Kultuk-Turka route in 2018 and along the Gremyachinsk-Monakhovo route in 2019. In summer period 2018 along the entire route, increased concentrations of SO2, CO, NO2 were observed in Noviy Enkhaluk with averaged values of 7.4 g/m3, 2.8 mg/m3 and 11 g/m3, respectively. Analysis of the obtained data of measurements of small gas impurities on the Gremyachinsk-Monakhovo route shows that the content of sulfur dioxide in the Barguzin Bay is 3 times higher than the data obtained in 2018 on the Kultuk-Turka route. The high level of SO2 is due to the current weather situation associated with fires in large forest areas.

Effect of cloudiness on the vertical distribution of chlorophyll a and zooplankton in Barguzin Bay of Lake Baikal: a numerical experiment

The objectives of this article are to describe the effect of cloudiness on the content of chlorophyll a and zooplankton on an example of Barguzin Bay of Lake Baikal using mathematical modeling. In this study, numerical experiments with various values of cloud coverage have been implemented. Simulations demonstrate that cloudiness essentially influences the vertical distribution of chlorophyll a and zooplankton in the open lake.

Giant ice rings on lakes and field observations of lens‐like eddies in the Middle Baikal (2016–2017)

AbstractGiant ice rings (diameter 5–7 km) detected on lakes Baikal (Russia) and Hovsgol (Mongolia) are a surface manifestation of intrathermocline lens‐like eddies under ice cover. By analyzing satellite imagery, we have detected new ice rings in 2016 and very old ones in 1969 for Lake Baikal. We have also discovered a giant ice ring on a new water body—Lake Teletskoye in the Altai Republic (Russia). Our recent field observations in the Middle Baikal have high temporal and spatial resolution and coverage and include temperature and current measurements over a long (1.5 month) period. In 2016, an eddy was detected in February and then an eddy and ice ring were detected in March at the same location. In 2017, another eddy was detected in February. This eddy was not stationary, as it was detected 6 km from its initial position in March, and thus no ice ring formed. The results of our field observations provide new data on the size and shape of the eddies. Indirect and direct measurements of currents and temporal evolution of the temperature field make it possible to estimate the rotation period (3 d) for the eddy in 2016 and assess the timing of movement, position, and displacement speed of the eddy in 2017. Thermal infrared Landsat imagery before ice formation in November–December 2015 shows that the eddy in 2016 was formed by the wind‐induced outflow from the Barguzin bay.

Transformation of the chemical composition of waters from the Barguzin River in the Barguzin Bay (Lake Baikal)

We have studied the changes in the chemical composition of the Bargizin River waters that inflow to Lake Baikal under the different water level. We have shown that river and lake waters that involved in the mixing differ in the ion composition and temperature. Despite this, the mixing in the Barguzin Bay under the influence of circulation currents and thermal barrier occurs in a comparatively narrow coastline, which is usually less than four kilometres. Mixed waters distribute north- and northwestward and reach the southern end of the Svyatoy Nos Peninsula. In summer, the distribution scale of river waters in the bay becomes greater but is mainly limited to the surface layer. In the central part of the bay, within one-two kilometres from the river estuary, a lens of lake waters can form. Not only the change in the chemical composition and temperature of the water but also its colour indicate the influx of these waters. The change in the concentrations of individual ions at a distance from the estuary of the Barguzin River occurs linearly, which indicates ordinary dynamic mixing of river and lake water masses.

Abundance and pigment type composition of picocyanobacteria in Barguzin Bay, Lake Baikal

In Lake Baikal, picocyanobacteria are the most important primary producers during the summer. Freshwater picocyanobacteria are discriminated into either the phycoerythrin (PE)-rich or the phycocyanin (PC)-rich types according to their pigment composition. The distributions of these two types of picocyanobacteria were investigated in Barguzin Bay. The PC-rich type accounted for >98% of the total picocyanobacteria at the station near the shore of the bay where river water flows directly in. In the offshore area of the lake, all of the picocyanobacteria cells were of the PE-rich type. In addition, the occurrence of the PC-rich type was restricted to the station, where the attenuation coefficient exceeded 0.25 m−1. Near the shore, where the turbidity was high (>1 NTU), the cell densities of both the PE- and PC-rich types increased away from the river mouth. This indicates that the PC-rich type cells grow near the shore of the bay where turbidity is high. Since the PC-rich type could not grow well when cells were incubated in offshore lake water, restricted distribution of the PC-rich type could also be explained by their growth capability. The present study clearly demonstrated the shift in the pigment type composition of picocyanobacteria from the coastal to the pelagic zone of Lake Baikal. The co-existence of the two pigment types probably enables the abundance of the picocyanobacterial community to be stable over a broader range of environmental conditions than would be possible for a single pigment type.

Abundance, growth and grazing loss rates of picophytoplankton in Barguzin Bay, Lake Baikal

The abundance, growth, and grazing loss rates of picophytoplankton were investigated in August 2002 in Barguzin Bay, Lake Baikal. Water samples for incubation were taken once at a near-shore station and twice at an offshore station. Contributions of picophytoplankton to total phytoplankton were high (56.9–83.9%) at the offshore station and low (5.8–6.8%) at the near-shore station. The picophytoplankton community in the offshore station comprised mainly phycoerythrin (PE)-rich cyanobacteria, with eukaryotic picophytoplankton being less abundant. In contrast, as well as PE-rich cyanobacteria and eukaryotic picophytoplankton, phycocyanin (PC)-rich cyanobacteria were found in the near-shore station. At the offshore station, growth and grazing loss rates on 25 August were 0.56 and 0.43 day−1, respectively, and on 29 August, 0.69 and 0.83 day−1, respectively. At the near-shore station, growth and grazing loss rates were 1.61 and 0.70 day−1, respectively. These results show that there is a difference in the abundance, composition, and ecological role in the microbial food web of picophytoplankton between the near-shore and the offshore areas in Barguzin Bay.

Abundance and Community Structure of Picoplankton and Protists in the Microbial Food Web of Barguzin Bay, Lake Baikal

We examined the vertical abundance of bacteria, phytoplankton and protists along a transect of six stations from near-shore (Stn. 1) to off-shore (Stn. 6) in Barguzin Bay of Lake Baikal, in the summer of 2002. Chlorophyll concentrations at Stn. 1 were higher (>10μg l−1) than at the other five stations (<3μg l−1). Planktonic and sessile diatoms dominated at Stn. 1, while pico-phytoplankon was dominant at other stations. Densities of heterotrophic bacteria were high in both the epilimnion and the thermocline at all stations. Nanoflagellates were abundant in the epilimnion, and ciliates in the thermocline, but no horizontal trend could be found for these heterotrophs. At Stn. 1, not only filter feeding (Strombidium and Strobilidium) and raptorial (Balanion) ciliates but also predatory ciliates (Prorodon and Spathidiosus) dominated, while at other stations only the filter feeding and raptorial ciliates were dominant. In off-shore stations (Stns. 5 and 6), significant correlations were detected between concentrations of chlorophyll a and density of filter feeding or raptorial ciliates, suggesting tight food linkages between phytoplankton and these ciliates. The concentration of dissolved organic carbon (DOC) was significantly correlated with chlorophyll a concentration, although there was no significant correlation between DOC concentration and bacterial density. We suggest that there is a shift of the dominant food linkage from a herbivorous food chain in near-shore areas to a microbial food web in off-shore areas in Barguzin Bay of Lake Baikal.