Baikal Research Articles

Freshwater Sponges as a Neglected Reservoir of Bacterial Biodiversity.

Freshwater sponges (Spongillida: Demospongiae), including more than 240 described species, are globally distributed in continental waters (except for Antarctica), where they cover both natural and artificial surfaces. However, fragmentary studies have targeted their microbiome, making it difficult to test hypotheses about sponge-microbe specificity and metabolic relationships, along with the environmental factors playing key roles in structuring the associated microbial communities. To date, particular attention has been paid to sponges (family Lubomirskiidae) that are endemic to Lake Baikal. Few other freshwater sponge species (e.g., Ephydatia spp., Eunapius spp., and Spongilla lacustris), from lakes and rivers spanning from Europe to South and North America, have been targeted for microbiological studies. Representatives of the phyla Proteobacteria, Bacteroidetes, and Actinobacteria largely predominated, and high differences were reported between the microbiome of freshwater and marine sponges. Several bacterial strains isolated from freshwater sponges can produce bioactive compounds, mainly showing antibiotic activities, with potential application in biotechnology. Understanding the roles played by sponge microbiomes in freshwater ecosystems is still in its infancy and has yet to be clarified to disentangle the ecological and evolutionary significance of these largely under-investigated microbial communities. This review was aimed at providing the main available information on the composition and biotechnological potential of prokaryotic communities associated with healthy freshwater sponges, as a neglected component of the global sponge microbiome, to stimulate researchers interested in the field.

Study of Interannual Variability of the Winter Mesothermal Temperature Maximum Layer in Southern Baikal

This paper is devoted to the study of the mesothermal temperature maximum layer (MTML) in Lake Baikal, which is observed during the period of winter stratification. On the one hand, this is a rather well-known phenomenon; on the other hand, it is not sufficiently studied, although it has a significant impact on the thermal regime in winter and water dynamics during the periods of formation and breakdown of inverse temperature stratification. Our work presents the results of analyzing the spatial and temporal variability of the main MTML parameters and their dependence on hydrometeorological factors. For this purpose, CTD soundings and mooring data obtained in the western part of the southern basin of Lake Baikal in 2000–2022 were analyzed in comparison to ERA5-Land reanalysis. The MTML parameters have noticeable within-season and interannual spatial and temporal variability. This is obviously related to the influence of the processes of vertical turbulent mixing, internal wave action, and current patterns. The analysis of interannual differences revealed four types of behavior of the maximum MTML temperature during the ice season. The influence of wind conditions on the main MTML parameters (maximum MTML temperature, depth of its occurrence, and depth of the upper MTML boundary) was shown not only in the fall, but also in the summer period, when heat accumulation in the Baikal water column takes place. With the increased wind activity in the late fall, the MTML is formed deeper and has lower maximum temperature values. At lower wind activity in the fall, the MTML is closer to the surface and the values of the maximum MTML temperature are higher. A change in wind activity in the summer leads to the opposite effect. In spite of the essential trends over the study period in the dates of the occurrence of hydrological events, no noticeable trends were registered for the maximum MTML temperature, its depth, and the depth of the upper boundary of the MTML.

Characteristics of spring Mongolian cyclones in the recent 70 years: Background circulations and weather influences

AbstractBased on the fifth‐generation reanalysis (ERA5) data of the European Centre for Medium Range Weather Forecasts (ECMWF), spring Mongolian cyclones were examined from 1950 to 2023. Then, based on the feature parameters of activity path information, machine learning method (k‐means) is used to classify the trajectories of spring Mongolian cyclone. Subsequently, the atmospheric circulation configurations of the three categories of Mongolian cyclones and their influence on the weather in China verify the reasonability of the classification method. Specifically: (1) eastward moving type, affecting Inner Mongolia and Northeast China (Clus‐1). The circulation background of the Clus‐1 cyclone displays a broad negative geopotential height anomaly centre over East Asia; (2) northeastward moving type, affecting northeast part of Northeast China (Clus‐2). The circulation background of the Clus‐2 cyclones shows a “positive–negative–positive” distribution of circulation anomalies in the European Plain, Lake Baikal and the Sea of Japan; (3) southeastward moving type, this type can move to the south of China (Clus‐3). The circulation background of the Clus‐3 cyclones is opposite to that of the Clus‐2 cyclones. The three categories of Mongolian cyclones will cause dust weather and strong winds in different regions of China, mainly affecting Inner Mongolia and Northeast China.

Regional seismic risk assessment based on the Unified Scaling Law for Earthquakes: The Lake Baikal railway system

Seismic hazard assessment (SHA) and evaluation of seismic risk (SR) require an adequate understanding of the actual distribution of earthquakes over magnitude, space, and time ranges. Neo-deterministic seismic hazard assessment (NDSHA) methodologies have been developed to improve the reliability and accuracy of reproducible seismic hazard maps. In the last decade, the application of NDSHA in many regions of the world has confirmed the availability of reliable and effective input for mitigating object-oriented earthquake risks NDSHA results have passed intensive testing by historical evidence and realistic modelling of scenario earthquakes. We used two NDSHA tools – (i) Unified Scaling Law for Earthquakes (USLE) and (ii) anisotropic propagation of the seismic effect – to evaluate SR for the Lake Baikal regional railroad system represented by Open Street Map (OSM) data of tracks, bridges and tunnels on the basis of seismic hazard maps of maximum macroseismic intensity expected in 50 years with 10%, 5%, and 1% probability of exceedance. We compare the achieved USLE−based results with the SR evaluations based on the General Seismic Zonation 2016 maps at identical levels of probability of exceedance.

Summer Extreme Rainfall Over the Middle and Lower Reaches of Yangtze River: Role of Synoptic Patterns in Historical Changes and Future Projections

AbstractIt is one of the major challenges in climate science to project future changes in extreme rainfall. To overcome this challenge, in this study, four typical synoptic patterns (SPs) triggering summer extreme rainfall over the middle and lower reaches of Yangtze River (MLYR) are identified through hierarchical clustering. These typical SPs share common characteristics of intensified Mei‐yu trough and Western Pacific Subtropical High but differ in terms of mid‐latitudes disturbances, such as an intensified ridge (Cluster 1, Cluster 2) or trough (Cluster 3, Cluster 4) near Lake Baikal (Cluster 1, Cluster 3) or Northeast China (Cluster 2, Cluster 4). The linkage between extreme rainfall and typical SPs is verified at various time scales. The typical SPs associated with extreme rainfall are substantially different from the circulation patterns found on ordinary days, and their frequency is significantly correlated with that of extreme rainfall across the interannual scales. Furthermore, the distinct changes in different typical SPs serve as a “bridge” for understanding the long‐term impact of circulation changes on local extreme rainfall, even though the two do not appear to be connected at first sight. Specifically, the circulation changes imply more (less) frequent SP‐Cluster 1 (SP‐Cluster 3), which tends to produce more extreme rainfall to the south (north) of the Yangtze River within MLYR. To project future changes in extreme rainfall, we utilize a weighting method for the multi‐model ensemble based on each model's capability to capture the observed typical SPs. This method effectively narrows the inter‐model spread.

Parasite fauna of sand and stone sculpins (scorpaeniformes, cottidae) from lake Baikal (review of research results and prospects of investigations)

A revision of the composition of parasites of two widely distributed in Baikal species of cottoid fish - the sand ( Leocottus kesslerii Dybowski, 1874) and the stone ( Paracottus knerii Dybowskii, 1874) sculpins was performed. This composition includes 60 species and subspecies of parasites belonging to 10 types, 12 classes, 14 orders, 24 families and 32 genera. It is represented by 21 endemic taxa of species and subspecies rank: these are blood parasites - trypanosomes and cryptobia (2), myxosporidia (5), infusoria (7), monogeneans (1), nematodes (2), acanthocephales (1), leeches (2) and crustaceans (1). Comparison of the parasite fauna of sand and stone sculpins with that of the families Abyssocottidae and Comephoridae showed that most of all this fauna is closely related to the parasite fauna of the family Abyssocottidae. Revision of the parasite composition of two widely distributed fish in Baikal in the light of modern data has identified a number of important problems in the study of fish parasites of this reservoir. Since there has been a transformation of views on the taxonomy of individual groups, new information has been obtained on morphology, molecular biology, biochemistry, life cycles and distribution in the plant and animal world, it is necessary to continue the study of Baikal parasites by modern methods.

Инструментальные компоненты цифровой платформы экологического мониторинга Байкальской природной территории

Статья посвящена проблемам взаимодействия сервисов, создаваемых разными разработчиками при формировании информационно-аналитических систем поддержки научных исследований. Для унификации параметров вычислительных сервисов предложены требования и рекомендации к создаваемым сервисам. Рассмотрены компоненты разработанной авторами цифровой платформы экологического мониторинга Байкальской природной территории, обеспечивающие алгоритмизированное взаимодействие всех участников исследований на основе композиций сервисов. To implement digital environmental monitoring of the Baikal natural territory, a digital platform has been developed at IDSTU SB RAS. Researchers from 16 scientific institutes, as well as employees of departmental organizations are collaborators of the project that provides support for a comprehen- sive analysis of monitoring data, forecasting and development of recommendations for the conservati- on of Lake Baikal and surrounding areas. The CPU is implemented on the basis of a service- oriented architecture that provides the ability to create services for collecting, presenting and processing data to all research participants. New services can be formed, among other things, based on a composition of services previously created by various platform participants. The article discusses the problems of interaction between services created by different developers. To unify the parameters of computing services, requirements and recommendations for the services being created are proposed. The components of the digital platform for environmental monitoring of the Baikal Natural Territory, developed by the authors, are considered, providing algorithmic interaction of all research participants based on service architecture. The approach proposed by the authors allows partially solving the problem of unifying services according to the types and formats of input and output data and the appropriate sources. The developed set of software components is actively used in practice. More than 200 data services and more than 40 data processing services have been created.

Agonistic behavior of the Baikal seal Pusa sibirica (Gmelin, 1788) on a coastal rookery: aggressive and pacifying patterns

The purpose of the article was to describe the agonistic behavior of the Baikal seal Pusa sibirica at the coastal rookery based on the analysis of video materials obtained during continuous fi lming over several seasons at one of the main coastal rookeries on Dolgiy Island (Ushkany Islands, Lake Baikal). The original ethogram of aggressive and pacifying behavior was compiled for the species, including 20 behavioral patterns. Visual patterns play a predominant role in agonistic relations of seals at coastal rookeries. Due to diverse pacifying patterns, the Baikal seal can gather in relatively numerous haul-outs (tens of individuals) in a limited space of coastal rookeries and coexist quite peacefully without causing signifi cant damage to each other, limited to rare minor injuries. Almost all agonistic interactions of seals on coastal rookeries are caused by competition for territory, a limited resource. The most common is front fl ipper swing and fl ipper hit (imitation and contact). The frequency of its use (48–64%) depends on the density and size of the substrate. Frequency of fi ghts in the water is up to 18%. Other commonly used pacifying patterns include tactile infl uences of varying intensity (up to 55%) and descent into the water or fl ight (8–18%).

Spatial patterns of torrential rain in the Haihe River Basin and the corresponding large‐scale circulation

AbstractThe classification of torrential rain is crucial to the flood mitigation and water resources, but the relevant research in the Haihe River Basin (HRB) is lacking. In this study, 156 regional torrential rain events from 1972 to 2022 were classified into two types using cluster analysis: eastern type and southern type. The eastern type is the typical torrential rain in the HRB, accounting for 61.5% of the total days, whereas the southern type mainly occurs in the piedmont plain with larger intensity and scope, which would pose more severe hazards. Corresponding large‐scale circulation patterns of the two types reveal a clear relationship between the HRB torrential rain and ascending motion, associated with the anomalies of low‐level moisture convergence and upper‐level wind divergence. The anomalous upper‐level divergence is accompanied by the northward expansion of South Asian High and intensified westerly jets. In the eastern type, strong low‐pressure anomalies north of Lake Baikal at mid‐level produce anomalous northwesterlies. The cold air from mid–high latitudes encounters enhanced southwesterly moist air accompanied by the northward expansion of Western Pacific Subtropical High (WPSH), resulting in the low‐level moisture convergence. In the southern type, the low‐level anomalous convergence is caused by a relatively weak cyclonic anomaly and significantly strengthened southeasterly moisture from the Pacific. The enhancement of southwesterlies results from the cooperative effect of the remarkably northwesterly WPSH and low‐pressure anomalies in South China Sea. As a whole, the eastern type is the result of convergence of cold air and southwesterly moisture driven by a dipole pattern at mid–high latitudes, whereas the southern type is mainly attributed to the accumulation of abundant southeasterly water vapour. This classification can identify high‐risk areas for torrential rain in the HRB and contribute to the forecast skills of extreme precipitation.

Virophages Found in Viromes from Lake Baikal.

In this study, a previously little-studied group of viruses-virophages-was searched for and identified in the viromes of the ancient oligotrophic Lake Baikal. Virophages are small dsDNA viruses that parasitize giant viruses (e.g., Mimiviridae), which in turn affect unicellular eukaryotes. We analyzed eight viromes obtained from the deep-water areas of three basins of Lake Baikal and the shallow-water strait Maloye More in different seasons. The sequences of virophages were revealed in all viromes and were dominant after bacteriophages and algal viruses. Sixteen putative complete genomes of virophages were assembled, all of which contained four conserved genes encoding major capsid protein (MCP), minor capsid protein (mCP), maturation cysteine protease (PRO), and FtsK-HerA family DNA-packaging ATPase (ATPase). The MCP-based cluster analysis showed a sequence separation according to seasons, and a dependence on the geographical localization was not detected.

Seed efficiency of Pinus sibirica and Pinus pumila hybrids on Lake Baikal shore

Two 5-needle pine species, Pinus sibirica and P. pumila, have vast geographic distribution and form wide hybrid zone in the Eastern Siberia. In the interspecies hybridization studies, seed production of hybrids has primary significance for further evolution of the cross-pollinated species. Seed efficiency of the hybrids and their parental species found on the eastern shore of Lake Baikal was studied. It was shown that mature cones of the hybrids were smaller than that in P sibirica but bigger than that in P. pumila. Seed efficiency, i. e., portion of ovules which give rise filled seeds with well-developed embryo, of the hybrids was 34.0 % and was almost 2-fold less than that in P. pumila (66.2 %) and quite comparable with that in P. sibirica (36.8 %). Low seed efficiency in P. sibirica was due to low seed formation frequency and high portion of empty seeds. Main reproductive losses in the hybrids occurred at all stages from the seed development beginning, portions of the aborted and empty seeds were especially high. Thus, seed efficiency of the hybrids appears high enough for further renewal, but, as a rule, only F1 hybrids are found on Lake Baikal shore.

Chemical elemental composition of Elodea canadensis Michx. 1791. and its use for the assessment of anthropogenic pollution of the littoral of Lake Baikal

The ICP-MS method was used to study chemical elemental composition of the invasive species Elodea canadensis Michx. at Lake Baikal littoral sites with different degree of anthropogenic load. It is found out that dominant macroelements in E. canadensis are K > Ca > Na > P > Mg > S > Cl, dominant microelements are Fe, Mn > Si, Sr > Al, Ba, Zn > Br, B. The content of Ca, Sr, Mg, B and Si in E. canadensis samples are characterized by the least variability, and Na, P, Cl, K, V, Ni, Cu, Zn, As, Se, Br, Rb, Cd, I, Pb contents are more variable. The maximal heterogeneity in distribution is characteristic for lithophilous elements (Be, Al, Ti, Cr, Mn, Y, Zr, Nb, REE (rare earth), Hf, Ta, W, Th) as well as for Fe, Co, Sn, Sb, Bi. Maximal contents of Na, Cl, K and P associated with income of household waste waters into the near-shore zone is found in Elodea samples collected in Frolikha vent and at littoral sites adjacent to such populated areas as Gremyachinsk, Maksimikha, Nizhneangarsk. The elevated level of Zn, Cd, Pb is characteristic as well for the samples collected at the littoral sites with a high anthropogenic charge (Listvyanka settl., Bugul’deyka, Nizhneangarsk, Maksimikha village and Gremyachinsk).

The diversity of the antimicrobial resistome of lake Tanganyika increases with the water depth

The presence of antimicrobial resistance genes (ARGs) in the microbiome of freshwater communities is a consequence of thousands of years of evolution but also of the pressure exerted by anthropogenic activities, with potential negative impact on environmental and human health. In this study, we investigated the distribution of ARGs in Lake Tanganyika (LT)'s water column to define the resistome of this ancient lake. Additionally, we compared the resistome of LT with that of Lake Baikal (LB), the oldest known lake with different environmental characteristics and a lower anthropogenic pollution than LT. We found that richness and abundance of several antimicrobial resistance classes were higher in the deep water layers in both lakes. LT Kigoma region, known for its higher anthropogenic pollution, showed a greater richness and number of ARG positive MAGs compared to Mahale. Our results provide a comprehensive understanding of the antimicrobial resistome of LT and underscore its importance as reservoir of antimicrobial resistance. In particular, the deepest water layers of LT are the main repository of diverse ARGs, mirroring what was observed in LB and in other aquatic ecosystems. These findings suggest that the deep waters might play a crucial role in the preservation of ARGs in aquatic ecosystems.

NEW FINDINGS OF MUD VOLCANISM IN NORTHWEST COAST OF LAKE BAIKAL BASED ON UNDERWATER VIDEO RECORDING

We present new data on manifestations of mud volcanism accompanied by gas emissions in Lake Baikal. Brittle deformations of the bottom with traces of erupted liquefied sediments were found in the Malaya Kosa Bay and the Goryachinskaya Bay in the North Baikal depression at depths of 105–163.6 m. The deposits outcropping in the extended scarps and mud craters are mainly represented by highly-porous clays. In places there are ledges of boulder-pebble sediments. The areas of the mud volcanism distribution are confined to the damage North Baikal fault zone, indicating its current activity. Disturbance of the clays and soft sediments covering them indicates the recent eruption of gas-saturated fluid and mud. At depths of 157–162 m in the Goryachinskaya Bay, cone-shaped structures ∼5 × 5 cm in size with a crater in the top part were found in them. Similar griffons were revealed in the Solontsovaya Bay along rectilinear faults opposite the paleoseismic rupture of the same name. It is necessary to continue studying the revealed shallow-water manifestations of mud volcanism and rupture deformations of the bottom by staging complex geological and geophysical studies.

Structural Changes of Phyto- and Zooplankton under the Influence of Climate Change and Anthropogenic Load (Lake Baikal, Russia)

Structural Changes of Phyto- and Zooplankton under the Influence of Climate Change and Anthropogenic Load (Lake Baikal, Russia)

THE USHKAN’Y ISLANDS, LAKE BAIKAL, AND THEIR ROLE AND SIGNIFICANCE IN THE LIFE OF THE BAIKAL SEAL (<i>PUSA SIBIRICA</i> GMELIN 1788, PINNIPEDIA) IN MODERN CONDITIONS

For the first time, a detailed description of the coastline of the Ushkan’y Islands, Lake Baikal is given in order to assess the use of the shore by the Baikal seal (Pusa sibirica Gm.) as haulouts, and the role these haulouts play in the annual cycle of seals. To do this, video material obtained using the DJI UAV Mavic 2 Zoom (take-off weight 905 g) and Air 2 S (take-off weight 595 g), as well as long-term field observations were used. A complete survey of the coastline of all four islands was carried out on May 29th and 30th, 2022 (at a water level of 456.40 m a.s.l.) and on August 12th and 24th (water level 456.79 and 456.83 m, respectively). Based on lithological characteristics, about 30% coastline on the Bolshoy Island, the largest one, is shown to be suitable for use by seals, but currently this is not the case. Among the three smaller islands, the most favorite place for the formation of seal haulouts is the Kruglyi Island, based on the total number of animals recorded on the island and in coastal waters, followed by the Tonkiy Island and then the Dolgiy Island, the latter supporting a stationary video system transmitting information online. On all islands, coordinates of specific haulout/rookery locations have been determined. Currently, about 35% length of the coastline of the three smaller Ushkan’y Islands are being used by seals for haulouts to one degree or another. Under current climatic conditions, the rookeries on the smaller Ushkan’y Islands seem to play extremely important roles for a significant part of the population (several thousand individuals visit them every season), since most other rookeries and locations that seals could use as such are highly susceptible to anthropogenic impacts.

Peculiarities of legal protection of natural world heritage sites in Australia on the example of the Great Barrier Reef

The study examines the practice of legal protection of the Great Barrier Reef World Heritage Site located in Australia. It reflects the main content of the decisions of the World Heritage Committee and the International Union for Conservation of Nature on the protection of the Great Barrier Reef, looks at the features of its management as a World Heritage Site (hereinafter also - WHS), as well as regulatory and organisational solutions aimed at preventing threats to the ecological state of the Great Barrier Reef WHS. The analysis of the legal framework and practice of protection of World Heritage Sites allows to conclude that some elements of the Australian experience can be used to strengthen the institutional and legal framework of the environmental regime of Lake Baikal. The proposal to develop a management plan for the Lake Baikal World Heritage Site in accordance with the requirements and standards of the World Heritage protection system, as well as to adopt special strategic development plans has been formulated. According to the authors, to ensure the effective development of specific management decisions, it is necessary to establish normatively the general principles of management plan formation. Based on the practice of engaging local communities in the management of World Heritage Sites and Australian experience of organising Marine Advisory Committees, the authors have verbalized a proposal to create an Advisory Council of representatives of various spheres of society, operating in the territory of the Lake Baikal World Heritage Site, environmental organisations and representatives of the public.

Chemical Composition of the Hydro-Cryogenic System of Lake Baikal: Snow on Ice–Ice–Water under Ice

Chemical Composition of the Hydro-Cryogenic System of Lake Baikal: Snow on Ice–Ice–Water under Ice

Lagrangian Simulations of Moisture Sources for Northeast China Precipitation during 1979–2018

Abstract In this study, the Flexible Particle Dispersion Model (FLEXPART) is applied to analyze the moisture sources of Northeast China precipitation from March 1979 to February 2018. The results show that there is mainly one particle aggregation channel in winter, namely the eastern Europe–Siberia–Lake Baikal–Northeast Asia channel (the western channel). In comparison with winter, there are two extra channels in summer, namely the Indochina Peninsula–South China Sea–East China channel (the southern channel) and the Philippine Sea–Ryukyu Islands channel (the southeastern channel). From the long-term mean, the Siberia–Mongolia–Xinjiang region (SMX) is the most dominant moisture source of Northeast China precipitation in all seasons. As for the moisture contribution rate of each source region to Northeast China precipitation, there is a seesaw interannual relationship between SMX and other source regions. The moisture from Central and East China is critical to the interdecadal shift of Northeast China summer precipitation. This interdecadal shift is related to the moisture transport from low latitudes to Northeast China, which is modulated by the positive phase of the Pacific decadal oscillation and the negative phase of the Atlantic multidecadal oscillation.

Geoinformational Analysis of NDVI in the Lake Baikal Basin

Geoinformational Analysis of NDVI in the Lake Baikal Basin