Baikal Research Articles

The Influence of Waters of Lake Baikal on the Spatiotemporal Dynamics of Phytoplankton in the Irkutsk Reservoir

On a model natural object, the Lake Baikal–Angara River–Irkutsk Reservoir (IR), we studied changes in the qualitative and quantitative characteristics of phytoplankton communities over three seasons in 2023 depending on seasonal changes in habitat parameters. Of the 151 identified taxa, Chrysophyta (57), Chlorophyta (41) and Bacillariophyta (24) predominated in diversity. Over the entire observation period, the highest values of total biomass and total abundance were detected in the IR in June (hydrological spring) at a water temperature of 10.0–12.7 °C, and the lowest in August, despite the fact that the water warmed up to 20 °C. No mass blooms of Cyanobacteria were observed. Statistical analysis of species abundance profiles revealed that phytoplankton community structure varied across time and space. The direct effect of cold lake waters on the structure of phytoplankton in the reservoir was observed only in early June. In summer and autumn, the structures of phytoplankton in the lake and in the reservoir differed, even at the same water temperature. Low concentrations of phosphates and nitrates, high species diversity, the presence of cold-water species and species with a wide range of temperature preferences formed a dynamic spatiotemporal structure of IR phytoplankton, distinct from other temperate reservoirs, including Lake Baikal. The results obtained are important for understanding the mechanisms of formation of the flora of artificial reservoirs of temperate latitudes and for their monitoring, taking into account seasonal dynamics and the context of global climate warming.

Morphological, ecological and genetic characteristics of the sandy sculpin (<i>Leocottus kesslerii</i>, Cottidae) from the lakes Baikal, Arakhlei and Gusinoe, Transbaikalia

Studies on local forms of the Sandy sculpin, Leocottus kesslerii, in the lakes Baikal, Arakhlei and Gusinoye show that the differences between lake forms in terms of external morphology lie in the head length to width ratio. In the Baikal form, the head is wider than long, vs the opposite in both Apakhlei and Gusinoe forms. In the Baikal and Gusinoe forms, there is a gap between the dorsal fins, a gap being absent from the Arakhlei form and the dorsal fins are in touch with each other. In the Arakhlei form, the anal fin is long (37.4–43%, on average 39.3% SL). In the Baikal form, the length of the A base reaches 32.9% SL (29.0–34.5%). In the Baikal and Arakhlei forms, small and sparse bone prickles are present on the body, these being large and dense in the Gusinoe form. The differences identified show a low level of morphological isolation of the forms. More significant differences are established in ecological features: growth rate, food spectrum, reproductive characteristics, and fecundity values. The differences in ecological features are due to the adaptation of the Sandy sculpin forms to specific conditions of the lakes they inhabit. Studies on genetic differentiation were carried out using the control region (CR) of mtDNA. The study forms of the Sandy sculpin revealed weak genetic isolation. The p-distances between the L. kesslerii forms averaged from 0.33 ± 0.12 to 0.51 ± 0.24%. Such low values of genetic distances clearly lie within the limits of intraspecific variability. The data obtained on the morphological, ecological and genetic differentiation of lake forms of the Sandy sculpin show that fish from the lakes Baikal, Arakhlei and Gusinoe belong to the same nominative subspecies, Leocottus kesslerii kesslerii.

Major Histocompatibility Complex Class II Genes Allele Diversity in Landlocked Seals.

The allelic diversity of exon 2 (DQB gene) and exon 3 (DRB gene) of major histocompatibility complex class II was studied for the first time in two species of the landlocked pinnipeds, Baikal (N = 79) and Caspian (N = 32) seals, and these were in compared with the widespread Arctic species, the ringed seal (N = 13). The analysis of the second exon comprising the antigen-binding region revealed high allelic diversity in all three species but the pattern of the diversity was the most specific for the Baikal seal. This species differs from the other two by the smallest number of alleles in the population, yet they have the largest number of alleles per individual and by the maximum similarity of individual genotypes. Presumably, this specificity is a consequence of the spatial and temporal homogeneity of the Lake Baikal environment. Analysis of the third exon encoding the conserved β2-domain showed that the Baikal seal differs by the greatest number of amino acid sequences per individual, while the Caspian seal has the lowest number of variants. A single variant of the β2-domain, the same as in the ringed seal, predominates in the Caspian seal, whereas in the Baikal seal the two other variants predominate. At the same time, three species-specific amino acid sequences were observed among minor variants in the Caspian seal, while only one was found in the Baikal seal. This fact may suggest a longer period of independent evolution in the Caspian seal compared to the Baikal seal.

New data on the stomatocysts of Spiniferomonas septispina Nicholls (Chrysophyceae, Chromulinales)

Morphotypes of stomatocysts in the Chrysophyceae class can serve as an additional criterion for determining species' taxonomic affiliations. This study provides a detailed description of the stomatocyst morphotype of Spiniferomonas septispina, a species with controversial taxonomic status owing to its structural similarity with Chrysosphaerella annulata. Analysis of the known morphotypes of Spiniferomonas stomatocysts reveals common features, including the presence of a collar or collar complex and an annulus. The stomatocyst morphotype of S. septispina exhibits ornamentation and a widely flared conical collar typical of Spiniferomonas species, distinguishing it from Chrysosphaerella. Based on these findings, we conclude that S. septispina should be classified under the genus Spiniferomonas. Additionally, the formation of S. septispina stomatocysts occurs in October in Lake Baikal at water temperatures ranging from 8.8 ℃ to 9.6 ℃.

The Ability of Gastropods of Lake Baikal to the Feeding and Excretion of Microplastic Particles with Different Morphological Structures

Studies of the pollution of Lake Baikal with microplastic particles have been started quite recently. Almost all research is focused on the assessment of surface water pollution, while the impact of microplastics on Baikal organisms remains unexplored. We conducted a laboratory experiment involving three species of gastropod mollusks, the Palearctic Lymnaea stagnalis (L., 1758) and Radix auricularia (L., 1758), as well as the Baikal endemic Benedictia baicalensis (Gerstfeldt, 1859). Two types of microplastics were used in the experiment: fragments of polystyrene and polyester fibers, prepared independently in the laboratory. These plastic particles, along with the food mixture, were placed in aquariums with mollusks. In total, as a result of the experiment, 386 preparations with mollusk excrement were obtained, of which 144 preparations were for the Radix auricularia species, 176 for the Lymnaea stagnalis species, and 67 for the Benedictia baicalensis species, the experiment with the latter species was carried out only with microplastic fragments. All preparations were analyzed according to the degree of fluorescence. The data were statistically processed using Spearman’s rank correlation coefficient. The data obtained allowed us to conclude that gastropods of these species are able to absorb microplastic particles and remove them from the body. However, the rate of removal of microplastic particles from the body of a mollusk is species-specific, and also directly depends on the morphological structure of microplastic particles.

Планово-высотная параметризация типов рельефа для диагностики опасных гравитационных процессов

The authors present the results of a comprehensive geomorphological analysis of the mountain relief types in the middle part of the Verkhnyaya Angara basin (lake Baikal region) for geoinformation diagnostics of dangerous gravitational processes. The relevance of the study is due to the increasing importance of the Baikal-Amur Mainline; the novelty lies in the fact that a high-precision plane-and-height assessment of the Baikal basin northern part’s hard-to-reach areas. The physical and geographical characteristics of the studied territory are given, tectonic and geological features of the relief formation are indicated. For the metric assessment and subsequent mapping of the terrain in the Arc GIS software environment, a digital model of the studied territory and raster coverings of morphometric parameters of slope and exposure were created based on isolines and elevation marks of the topographic base scale 1:100000. In the process of analyzing the model and geomorphological decoding of the arch-block mountains, the planned-altitude metric parameters of relief types with their characteristic forms and elements, morphometric properties with determining factors of formation and development of gravitational processes were established. High-mountain erosion-exaration-, denudation-erosion-; medium-mountain erosion-denudation-, denudation-erosion- and low-mountain denudation relief types are distinguished. For geomorphometric analysis and diagnostics of slopes, reference polygons characterizing the types of arch-block mountains relief, possessing certain geophysical properties and features were selected. To visualize each polygon, slope mapping-and-exposure was performed, as well as a satellite image was presented. As a result of the conducted research, a typical set of dangerous gravitational processes was identified for each type of relief, as well as their possible intensity, which can create risks of economic activity in mountainous areas. The results of the study can be used in design work for the modernization of the Baikal-Amur Mainline and the development of new mineral deposit

First record of <i>Canthocamptus (Canthocamptus) microstaphylinus</i> Wolf 1905 (Harpacticoida, Copepoda) from a shallow coastal area of Lake Baikal

Female and male specimens of the Palearctic species, Canthocamptus (Canthocamptus) microstaphylinus Wolf 1905, were found in the coastal zone of Lake Baikal, Siberia. This was the first record of the species in Lake Baikal and the Baikal region. A general description and brief morphological characteristics were made using scanning electron microscopy. The authors compared the principal diagnostic morphological traits of C. (C.) microstaphylinus from Lake Baikal and some water bodies from the European part of Russia (within the Syktyvkar City, Republic of Komi). As a result, specimens from Lake Baikal and the Syktyvkar area were shown to be similar in the structure of their thoracic appendages and caudal rami.

Nomenclature and systematics of two Cocconeis species (Bacillariophyta) from Lake Baikal: Cocconeisbaicalensis and Cocconeisskvortzowii.

The study provides nomenclatural history, morphological characteristics and taxonomy of Cocconeisbaicalensis and C.skvortzowii described by B.V. Skvortzov from Lake Baikal. The lecto- and epitypification of the names are made, based on the K.I. Meyer and A.P. Skabichevsky materials, ensuring compliance with current nomenclatural standards. The morphological traits of these species were thoroughly examined using light microscopy (LM) nd scanning electron microscopy (SEM), leading to refined diagnoses and the clarification of previously confused synonymy.

Redescription of Chrysosphaerella baikalensis (Chrysophyceae, Chromulinales) with new data on the ultrastructure of its stomatocysts

An amended description of the ultrastructure of plate and spine scales is provided, along with the first description of the stomatocyst Chrysosphaerella baikalensis from Lake Baikal. C. baikalensis exhibits four types of plate scales: small and large elliptical, large rounded, and large subcircular scales. The spines can grow up to 47 μm in length. The stomatocysts of C. baikalensis are spherical or slightly oblate, with a small, regular pore surrounded by a flat pseudoanulus, lacking a collar. Based on their surface ornamentation, two forms of stomatocysts are distinguished, Forma A covered with densely arranged short needle-like outgrowths and Forma B having a smooth to psilate surface. We associate the first form with the immature stage. In this article, we report the growth of C. baikalensis in Lake Baikal during June, in the open water period, at a water temperature of 3.9–4.5 °C. During this period, whole cells and stomatocysts covered with plate scales were observed. Individual spines and plate scales were found at temperatures up to 11.5 ℃.

Summer daily dynamics of the vertical structure of atmospheric aerosol over Baikal coastal area from ground-based lidar measurements

ABSTRACT The spatial structure of atmospheric aerosol over Baikal in summer is studied on a regular basis with the use of ground-based LOSA-M2 lidar measurements at the Boyarsky scientific station of the Institute of Physical Material Science, Siberian Branch, Russian Academy of Sciences (51.83°N, 106.06°E, 456 m a.s.l.), Republic of Buryatia, Russia. The lake is located in a basin surrounded by mountain ranges on all side; its water volume is large. The lidar data are analysed along with the regional meteorological situation and meteorological parameters of the atmosphere. The daily dynamics of aerosol distribution over the atmospheric is examined for the period from 2015 to 2023 accounting the effect of different air masses in the region. Three main typical air circulation types are identified for the coastal zone of southern Baikal in summer, which determine the atmospheric aerosol generation and transport. The first and most common type relates to breeze circulation, where the main changes in the spatial structure of aerosol occur in the 2–3-km layer and are determined by changes in the transport direction within a breeze cell during the day. The main feature of this type is a decrease in the altitude of an air layer which contains most of aerosol in the lower atmosphere up to 1 km. The second type refers to southwestern transport under the presence of an anticyclone over the region. The maximal altitude of the aerosol layers attains 7 km in this case. The most complex and dynamic changes in the daily spatial structure of atmospheric aerosol occurred under transport of cyclones and associated atmospheric fronts over Lake Baikal. Under this third type, the altitude of the aerosol layers decreases throughout the day within the altitude range from the surface to 3–4 km.

Estimation of inflow discharge to Lake Baikal at upstream section using different satellite-based precipitation and runoff datasets from Upper Angara and Kichera River basins in East Siberia, Russia

Accurate basin-level river discharge estimation is of vital importance across various fields, including water resources, climate change, natural hazards, biodiversity, and energy production. Normally, gauging stations are deemed the most reliable data source for measuring river discharge. However, a significant proportion of the world’s rivers remain ungauged due to a combination of technical, economic, and political constraints. Encouragingly, recent advancements in remote sensing and satellite observation have opened new avenues for global river discharge monitoring, even in ungauged basins, and the availability of extensive datasets and advancements in computing technologies have facilitated the development of numerous modern data-driven techniques. The general objective of this study is to estimate inflow discharge to Lake Baikal at upstream section from Upper Angara and Kichera River Basins using different satellite precipitation and runoff datasets. According to the calculation result, a higher discharge was observed for the power dataset. The obtained results were used to mitigate floods, droughts, bridge design, manage urban drainage systems, and manage the lake ecosystem.

Freshwater Habitats Promote Rapid Rates of Phenotypic Evolution in Sculpin Fishes (Perciformes: Cottoidea).

AbstractInvasions of freshwater habitats by marine fishes provide exceptional cases of habitat-driven biological diversification. Freshwater habitats make up less than 1% of aquatic habitats but contain ∼50% of fish species. However, while the dominant group of freshwater fishes (Otophysi) is older than that of most marine fishes (Percomorphaceae), it is less morphologically diverse. Classically, scientists have invoked differences in the tempo and/or mode of evolution to explain such cases of unequal morphological diversification. We tested for evidence of these phenomena in the superfamily Cottoidea (sculpins), which contains substantial radiations of marine and freshwater fishes. We find that the morphology of freshwater sculpins evolves faster but under higher constraint than that of marine sculpins, causing widespread convergence in freshwater sculpins and more morphological disparity in marine sculpins. The endemic freshwater sculpins of Lake Baikal, Siberia, are exceptions that demonstrate elevated novelty akin to that of marine sculpins. Several tantalizing factors may explain these findings, such as differences in habitat stability and/or habitat connectivity between marine and freshwater systems.

Anaerobic Oxidation of Oil by Microbial Communities of Bottom Sediments of a Natural Oil Seepage Site (Bolshaya Zelenovskaya, Middle Baikal)

The microbial communities of bottom sediments of the Bolshaya Zelenovskaya oil seepage site (Lake Baikal) were investigated to assess their diversity and potential functional activity in the anaerobic degradation of oil. Microorganisms of the subsurface and deep sediment layers were grown in enrichment cultures supplemented with oil and various electron acceptors for 1 year at 10°C, and it was found that the concentrations of n-alkanes and polyaromatic hydrocarbons decreased by 1.2–2 and 2.2–2.8 times, respectively. Hydrocarbon conversion was accompanied by generation of hydrocarbon gases (methane and ethane). The microbial community of subsurface sediments had a higher bacterial diversity than the community of deep horizons and was composed of microorganisms specialized in degradation of a broad range of substrates, including oil hydrocarbons. The community of the deep sediment layer was dominated by Atribacterota, Caldisericota, and Bathyarchaeia (Thermoproteota), as well as members of the “rare biosphere”: Elusimicrobiota and Candidatus Hadarchaeota. Apparently, oil degradation in the bottom sediments of Lake Baikal is primarily mediated by members of the phyla Bacillota, Pseudomonadota, Chloroflexota, Actinomycetota, Desulfobacterota, Atribacterota, Halobacteriota, and Bathyarchaeia (Thermoproteota).

The Source of Thermophilic Bacteria in Lake Baikal Cold Sediments – Coastal Hydrotherms or Deep Fluids?

The sources of thermophilic bacteria revealed in cold Lake Baikal sediments are considered. Comparative analysis of the taxonomic position of thermophilic microorganisms from four terrestrial hot springs at Lake Baikal coast and from the bottom sediments associated with hydrocarbon discharge was carried out. The sequences of thermophilic microorganisms with the same taxonomic position were revealed both in the hot springs and bottom sediments. Some microbial species occurred only in the hydrotherm samples or only in those from the sediments. Gas-saturated fluids from the hydrocarbon generation zone at the depth of 4‒6 km are the most probable source of thermophilic microorganisms in the bottom sediments.

Почвенные водоросли и цианопрокариоты степных сообществ Байкальской котловины

The article presents the results of studies of herbaceous plant communities in the Baikal basin, with the significant participation of the diazotrophic cyanoprokaryota Nostoc commune. The territory of the investigation is located at the foot of the Primorskiy range. There are developed mountain, typical steppe, and meadow communities on chestnut soils. A high content of carbonates was found in the soils, and the pH of the upper horizons varied from slightly acidic to alkaline. The composition of algae and cyanoprokaryota species living in and on soils has been revealed. In total, in steppe and meadow communities we identified 71 species from five divisions: Cyanoprokaryota – 27, Bacillariophyta – 4, Ochrophyta – 3, Chlorophyta – 34, and Charophyta – 3. 58 species have been found in steppe communities, 40 in meadow. A predominance of cyanoprokaryota and green algae was noted. The composition of the studied phototrophic species in steppe communities differed significantly from that of the meadow. In steppe communities Nostoc commune formed macroscopic colonies, and its biomass production was low (about 2 g/m2) comparable to that of a number of Asia arid territories. The N. commune biomass formation was higher on the mountain slope and at its foot, where higher density of soil composition, lower field humidity, as well as an increased content of calcium, magnesium, and sodium was found in soils. The N. commune biomass was reduced in the site at a distance from the mountain slope where the content of the above elements was lower. The regular sampling of macrocolonies had a negative impact on their renewal.

Global earthquakes in the first half of 2024 according to the GS RAS

Description of the Earth seismicity at the level of mb (MS)≥6.0 in the first half of 2024 is pro-vided. А total of 60 earthquakes are included in the list with such magnitudes. Also information on 77 earthquakes felt on the territory of the Russian Federation according to the Alert Service of the Geophysical Survey RAS is given. For the eight strongest events, information messages were published within one to two days after their occurrence, and parameters of their focal mecha-nisms were calculated. During the period under review, the strongest global earthquake with MS=7.7 (Mw=7.3) occurred on April 2 on the northeast coast of Taiwan Island. As a result, twelve people died and about a thousand were injured. The greatest human casualties and materi-al damage were caused by the catastrophic earthquake on January 1 with MS=7.3 (Mw=7.3) on the west coast of Honshu Island, Japan, which caused 240 deaths and 1,036 injuries. On the terri-tory of Russia, the most noticeable (intensity Ii=5 in the nearest settlements) were two earth-quakes: on January 15 with mb=5.5 (Mw=5.2) in the area of Lake Baikal in Buryatia and on May 6 with MS=5.0 (Mw=5.3) in the Chukotka Autonomous Okrug. The seismic energy released on the globe for the first half of 2024 (sum(E0.5)=1.29≥∙1017 J) increased compared to that in the 2023 second half, but remained below the average semi-annual value for the period of 2010–2023 (sum(E0.5)=2.24≥∙1017 J).

Features of Temporal Variability of the Concentrations of Gaseous Trace Pollutants in the Air of the Urban and Rural Areas in the Southern Baikal Region (East Siberia, Russia)

This article presents the results of the automatic monitoring of the concentrations of gaseous impurities of sulfur and nitrogen oxides in the ground-level atmosphere of the urban and rural areas in the Southern Baikal region (East Siberia, Russia). The study was conducted from 2020 to 2023 at the urban Irkutsk station and the rural Listvyanka station located at a distance of 70 km from each other. We calculated the main statistical characteristics of the variations in the concentrations of nitrogen oxides and sulfur dioxide in the ground-level atmosphere and determined a nature of variability in their concentrations on various time scales: annual, weekly, and daily. Annual variabilities of gaseous pollutants in the ground-level atmosphere above the Irkutsk city and the Listvyanka settlement were similar and showed the highest values in winter and the lowest in summer. The daily and weekly dynamics of the nitrogen oxide concentrations in the urban area clearly depended on the increase in the road traffic during rush hours (morning and evening). In the rural area, there was no such dependence. In this area, the daily and weekly variability in the concentrations of nitrogen oxides and sulfur dioxide mainly depended on natural meteorological processes. The work systematizes the meteorological parameters at which the largest amount of anthropogenic impurities enters the air basin of Lake Baikal. The maximum values of acid-forming gas concentrations were observed when the air masses were transferred from the northwest direction, which corresponds to the location of sources in the territory of the Irkutsk–Cheremkhovo industrial hub—the largest concentration of anthropogenic objects in the Irkutsk region.

Does the distribution of Wormian bone frequencies across different world regions reflect genetic affinity between populations?

BackgroundWormian, or sutural bones, are additional, irregularly shaped bone fragments that can occur within cranial sutures. These bones may arise due to various factors, including mechanical pressure on skull bones during early ontogenetic stages, such as during artificial cranial deformations, or due to genetic and environmental influences. This study investigates the potential genetic basis of sutural bones by comparing their frequencies across diverse global regions. It analyzed 33 craniological series, encompassing 2059 crania, to assess the frequency of sutural bones in the coronal, squamous, lambdoid, and occipitomastoid sutures among skeletal populations from regions including Aboriginal Australia, Melanesia, Southeast Asia, Siberia, Europe, and Native America. Biological distances between populations were calculated using Smith’s mean measure of divergence (MMD), with results visualized through multidimensional scaling.ResultsThe analysis identified distinct clusters of Caucasian and Siberian populations. Siberian aboriginal populations are compactly grouped, consistent with mtDNA data indicating genetic roots dating back to the Neolithic inhabitants of the Lake Baikal region. Further, differentiation within these populations is linked to the founder effect and gene flow. Notably, genetically related groups like the Inuit and Chukchi of Chukotka differ from other Siberian groups. In contrast, southern Siberian populations, such as the Buryats and Mongols, are closely positioned, aligning with genetic data. The differentiation between Southeast Asian and African regions was subtler, with their clusters largely overlapping. Yet, genetic links between populations were observed in some cases. Thus, Australians, Melanesians, and Papua New Guineans were located close to each other on the multidimensional scaling map, as were two African populations.ConclusionsThe findings tentatively suggest a potential genetic component in the expression of Wormian bones, although this hypothesis requires further empirical support, particularly through genetic studies. While genetic factors may influence the expression of Wormian bones, environmental conditions and pathological processes also play significant roles. It can be suggested that Wormian bones could potentially serve as an additional tool in kinship analysis within burials; however, their utility significantly depends on the extent of their genetic influence. If future genetic studies confirm a substantial genetic component and its dominance over environmental factors, the use of these bones in anthropological and forensic analyses would receive additional validation.

T4-Like Cyanophages of Lake Baikal: Genetic Diversity and Biogeography

The work deals with investigation of genetic diversity and biogeography of T4-like cyanophages from the shallow bay of the Posolsk Sor (Lake Baikal), based on analysis of the g20 marker gene. High diversity of g20 gene fragments and their uniqueness were revealed. The greatest similarity was noted with the previously obtained sequences from Lake Baikal and with those from freshwater ecosystems: oligotrophic Lake Green, Lake Round, oligomesotrophic Lake Ancy, and mesotrophic Lake Bourget. From the point of view of biogeography, it was determined that the phage sequences were similar to the previously obtained ones from different Lake Baikal ecotopes than to those from other ecosystems.

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.