Lakes In Mongolia Research Articles

Oligocene and early Miocene mammal biostratigraphy of the Valley of Lakes in Mongolia

The Taatsiin Gol Basin in Mongolia is a key area for understanding the evolution and dispersal of Central Asian mammal faunas during the Oligocene and early Miocene. After two decades of intense fieldwork, the area is extraordinarily well sampled and taxonomically well studied, yielding a large dataset of 19,042 specimens from 60 samples. The specimens represent 176 species-level and 99 genus-level taxa comprising 135 small mammal species and 47 large mammals. A detailed lithostratigraphy and new magnetostratigraphic and radiometric datings provide an excellent frame for these biotic data. Therefore, we test and evaluate the informal biozonation scheme that has been traditionally used for biostratigraphic correlations within the basin. Based on the analysis of the huge dataset, a formalised biostratigraphic scheme is proposed. It comprises the Cricetops dormitor Taxon Range Zone (Rupelian), subdivided into the Allosminthus khandae Taxon Range Subzone and the Huangomys frequens Abundance Subzone, the Amphechinus taatsiingolensis Abundance Zone (early Chattian), the Amphechinus major Taxon Range Zone (late Chattian), subdivided into the Yindirtemys deflexus Abundance Subzone and the Upper Amphechinus major T. R. Z., and the Tachyoryctoides kokonorensis Taxon Range Zone (Aquitanian). In statistical analyses, samples attributed to these biozones form distinct clusters, indicating that each biozone was also characterised by a distinct faunal type.

DUNALIELLA ЗАМГИЙН ФИЗИОЛОГИ, БИОХИМИЙН СУДАЛГААНЫ ДҮН

The genus Dunaliella is widely studied microalgae for its tolerance to extreme conditions, physiological aspects and many biotechnological applications, such as beta-carotene, protein, lipids and many other bioactive compounds. Physiological and biochemical studies are essential to fully explore the properties and possibilities of new isolates of Dunaliella.The aim of this study was to describe cellular morphology, growth rate and protein content of three Dunaliella strains, isolated from salty lakes in Mongolia. The cellular morphology, growth rates, protein contents were studied using microscopic analyses, Neubauer’s chamber, and micro kjeldahl method.Results showed that growths of all three Dunaliella cultures were progressed through lag phase at 3rd day. The growth of Dunaliella D-1 reached its peak on day 6, while Dunaliella D-6 and D-7 reached their stationary phase on day 7. Furthermore, the protein contents of dry biomass in Dunaliella D-1, D-6 and D-7 cultures were 62.2%, 36.1% and 38.15%, respectively. The highest protein content was found in Dunaliella D-1 culture, hence this culture could be used as protein rich supplement in further study.

Stepwise onset of the Icehouse world and its impact on Oligo-Miocene Central Asian mammals.

Central Asia is a key area to study the impact of Cenozoic climate cooling on continental ecosystems. One of the best places to search for rather continuous paleontological records is the Valley of Lakes in Mongolia with its outstandingly fossil-rich Oligocene and Miocene terrestrial sediments. Here, we investigate the response by mammal communities during the early stage of Earth’s icehouse climate in Central Asia. Based on statistical analyses of occurrence and abundance data of 18608 specimens representing 175 mammal species and geochemical (carbon isotopes) and geophysical (magnetic susceptibility) data we link shifts in diversities with major climatic variations. Our data document for the first time that the post-Eocene aridification of Central Asia happened in several steps, was interrupted by short episodes of increased precipitation, and was not a gradual process. We show that the timing of the major turnovers in Oligocene mammal communities is tightly linked with global climate events rather than slow tectonics processes. The most severe decline of up 48% of total diversity is related to aridification during the maximum of the Late Oligocene Warming at 25 Ma. Its magnitude was distinctly larger than the community turnover linked to the mid-Oligocene Glacial Maximum.

Characterization and Organic Compounds in Peloids from Mongolia

The peloids are the important natural remedy all over the world. The physicochemical properties and some organic matters of peloids from 12 lakes in Mongolia were examined. These peloids belong to the continental hydrosulfide sticky peloid except Gurvan nuur peloid. Peloid from Lake Gurvan nuur was classified as a sapropel with high ash content.The peloid organic matters were investigated using chemical analysis and several analytical techniques, such as IR, and 13C NMR spectroscopy, GC/MS, gas chromatography. The concentration of total organic carbon in all continental hydrosulfide sticky peloids is ranged from 0.4% to 3.1%, but 15.3% in the sapropel. It shows that the majority of the peloids in Mongolia are hydrosulfide sticky peloid with lower organic matters than the sapropel and peat. In this study, no significant difference of chemical composition was observed between dissoluble and insoluble organic matters from peloids. Some classes of biomolecules, including lipid and carbohydrate, were identified. Biogenic stimulator humic acid (HA) is the major part of the peloid organic matter. HA concentration varied between 11.2% and 55.9% of total organic matter of peloids. The macromolecule of the sapropel HA exhibited a lower aromatization degree and more functional groups than other HAs, as revealed by the 13C NMR data and C/H ratio. The genesis of peloid organic matter is discussed in this paper.Our results suggest that the presence of known bioactive organic compounds, such as humic acid, lipid, and carbohydrate, as well as hydrogen sulfide causes the balneological value of peloids in Mongolia.DOI: http://dx.doi.org/10.5564/pmas.v0i4.42Proceedings of the Mongolian Academy of Sciences 2009 No 4 pp.3-21

Characterization of H5N1 highly pathogenic avian influenza virus strains isolated from migratory waterfowl in Mongolia on the way back from the southern Asia to their northern territory

H5N1 highly pathogenic avian influenza (HPAI) viruses were isolated from dead wild waterfowl at Khunt, Erkhel, Doityn Tsagaan, Doroo, and Ganga Lakes in Mongolia in July 2005, May 2006, May 2009, July 2009, and May 2010, respectively. The isolates in 2005 and 2006 were classified into genetic clade 2.2, and those in 2009 and 2010 into clade 2.3.2. A/whooper swan/Mongolia/6/2009 (H5N1) experimentally infected ducks and replicated systemically with higher mortality than that of the isolates in 2005 and 2006. Intensive surveillance of avian influenza in migratory waterfowl flying from their nesting lakes in Siberia to Mongolia in every autumn indicate that HPAI viruses have not perpetuated at their nesting lakes until 2009. The present results demonstrate that wild waterfowl were sporadically infected with H5N1 HPAI viruses prevailing in domestic poultry in the southern Asia and died in Mongolia on the way back to their northern territory in spring.

Organic matters in healing muds from Mongolia

The physicochemical properties and characterization of some organic matters of peloids from 12 lakes in Mongolia were examined. These peloids belong to the continental hydrosulfide sticky peloid except Gurvan nuur peloid, which was classified as a sapropel with high ash content. The peloid organic matters were investigated using chemical analysis and several analytical techniques, such as IR, and 13C NMR spectroscopy, GC/MS, and gas chromatography. The concentration of total organic carbon in all continental hydrosulfide sticky peloids is ranged from 0.4 to 3.1 mass %, but 15.3 mass % in the sapropel. Thus, the majority of the peloids in Mongolia are hydrosulfide sticky peloids with lower organic content than the sapropel and peat. In this study, no significant differences in the chemical composition were observed between dissoluble and insoluble organic matters from peloids. Some classes of biomolecules, including lipids and carbohydrates, were identified. The biogenic stimulator humic acid was the major part of the peloid organic matter. HA concentration varied between 11% and 56% of total organic matter. The macromolecule of the sapropel HA exhibited a lower aromatization degree and more functional groups than other HAs, as revealed by the 13C NMR data and the C/H ratio. Our results suggested that the presence of known bioactive organic compounds, such as humic acids, lipids, and carbohydrates, as well as hydrogen sulfide, increase the balneological value of peloids in Mongolia.

Ectothiorhodospira variabilis sp. nov., an alkaliphilic and halophilic purple sulfur bacterium from soda lakes

During studies of moderately halophilic strains of Ectothiorhodospira from steppe soda lakes, we found a novel group of bacteria related to Ectothiorhodospira haloalkaliphila with salt optima at 50-80 g NaCl l(-1). Phylogenetic analysis using 16S rRNA gene sequences of strains from soda lakes in Mongolia, Egypt and Siberia revealed separation of the group of new isolates from other Ectothiorhodospira species, including the closely related Ect. haloalkaliphila. DNA-DNA hybridization studies demonstrated that the new isolates form a homogeneous group at the species level, but at the same time are distinct from related species such as Ect. haloalkaliphila, Ect. vacuolata, Ect. shaposhnikovii and Ect. marina. The new isolates are considered to be strains of a novel species, for which the name Ectothiorhodospira variabilis sp. nov. is proposed, with the type strain WN22(T) (=VKM B-2479(T) =DSM 21381(T)). Photosynthetic pigments of the novel species are bacteriochlorophyll a and carotenoids of the spirilloxanthin series with spirilloxanthin and derivatives thereof, together with small amounts of lycopene and rhodopin. Gas vesicles are formed by most of the strains, particularly in media containing yeast extract (0.5 g l(-1)) and acetate (0.5-2.0 g l(-1)). Sequence analysis of nifH (nitrogenase) and cbbL (RuBisCO) confirmed the assignment of the strains to the genus Ectothiorhodospira and in particular the close relationship to Ect. haloalkaliphila. The novel species Ect. variabilis is found in soda lakes separated by great geographical distances and is an alkaliphilic and halophilic bacterium that tolerates salt concentrations up to 150-200 g NaCl l(-1).

On estimation of phenetic relationships of Altai Osmans (Oreoleuciscus, Cyprinidae) from three lakes in Mongolia by skull characters

By four meristic and 14 morphometric characters of the skull the phenetic relationships of Altai Osmans of the genus Oreoleuciscus from lakes Ust-Nur (the Selenga Basin), Sangiyn-Dalai-Nur (the Khangai Highland), and Orog-Nur (Lake Valley) are estimated. Principal components analysis is performed. No interpopulational differences by the set of meristic characters are found. By the set of morphometric characters the specimens from Lake Ust-Nur in the space of principal components are separated from specimens from two other lakes while the distributions of specimens from Lake Sangiyn-Dalai-Nur and Orog-Nur overlap. With consideration of estimates of similarity in the structure of interpopulational differences it is assumed that separation of the phyletic line common for populations of lakes Ust-Nur and Orog-Nur from the phyletic line of population of Lake Sangiyn-Dalai-Nur preceded separation of phyletic lines of populations from lakes Ust-Nur and Orog-Nur.

Seismic strain in the Altai-Sayan active seismic area and elements of collisional geodynamics

Seismic strain estimated from about 900 earthquake mechanisms in the Altai-Sayan area indicates that the area evolves mainly under N-S compression caused by the India-Eurasia collision. Plastic flow in the mountains of the western and central Altai-Sayan area is controlled by convergence of aseismic rigid blocks, including the Dzungarian microplate, the Minusa basin, the Tuva basin, Uvs Nuur and other basins in the region of Great Lakes in Mongolia. Earthquake rupture follows the existing fault pattern. The pattern of rigid blocks and mountain ranges correlates well with upper mantle thermal heterogeneity as imaged by seismic tomography. Earthquake mechanisms in the presence of plate convergence depend on different factors. Slip geometry depends on focal depth at a given geodynamic regime, and the latter, in terms of the seismic process, is controlled by lateral (W-E) constraint. Reverse-slip earthquakes most often originate at shallow depths in regions of constrained compression, such as the Tien Shan, and strike slip is the dominant mechanism under non-constrained and moderately constrained compression. The direction of slip is governed by the parallel component of convergence and by the fault pattern. In regions of strain shadow, slip occurs mostly on normal planes, and shallow earthquakes have strike-slip mechanisms. The crust in the collisional region is divided into systems of rigid and plastic blocks (rheological structure) and of fault blocks (fault-block structure). The two types of systems coexist and determine the generally similar but specifically different features of local mass transfer.

Diversity of culturable halophilic sulfur-oxidizing bacteria in hypersaline habitats

Unexpectedly high culturable diversity of moderately and extremely halophilic obligately chemolithoautotrophic sulfur-oxidizing bacteria (SOB) was discovered in the sediments of various hypersaline habitats, including chloride-sulfate lakes in Mongolia, Russia and Ukraine, a sea saltern in Slovenia and a deep-sea salt brine from the Mediterranean. Six different groups of halophilic SOB, including four new genera, all belonging to the Gammaproteobacteria, were found. Two groups of moderately halophilic strictly aerobic SOB dominated at 2 M NaCl, including representatives of the genus Halothiobacillus (in fully aerobic conditions) and Thiomicrospira (in micro-oxic conditions). Under denitrifying conditions at 2 M NaCl, a group of moderately halophilic and facultatively anaerobic SOB was selected, capable of complete denitrification of nitrate. The group represents a new genus with closest relatives among as yet undescribed marine thiodenitrifying isolates. With thiocyanate as a substrate, an enrichment culture at 2 M NaCl yielded a pure culture of moderately halophilic SOB capable of aerobic growth with thiocyanate and thiosulfate at up to 4 M NaCl. Furthermore, this bacterium also grew anaerobically using nitrite as electron acceptor. It formed a new lineage distantly related to the genus Thiomicrospira. Enrichments at 4 M NaCl resulted in the domination of two different, previously unknown, groups of extremely halophilic SOB. Under oxic conditions, they were represented by strictly aerobic spiral-shaped bacteria, related to the Ectothiorhodospiraceae, while under denitrifying conditions a group of facultatively anaerobic nitrate-reducing bacteria with long rod-shaped cells was selected, distantly related to the genus Acidithiobacillus.

Genetic diversity and biogeography of haloalkaliphilic sulphur-oxidizing bacteria belonging to the genus Thioalkalivibrio

A group of 85 isolates of haloalkaliphilic obligately chemolithoautotrophic sulphur-oxidizing bacteria belonging to the genus Thioalkalivibrio were recently obtained from soda lakes in Mongolia, Kenya, California, Egypt and Siberia. They have been analyzed by repetitive extragenic palindromic (rep)-PCR genomic fingerprinting technique with BOX- and (GTG)5-primer set. Cluster analysis was performed using combined fingerprint profiles and a dendrogram similarity value (r) of 0.8 was used to define the same genotype. Fifty-six genotypes were found among the isolates, revealing a high genetic diversity. The strains can be divided into two major clusters, including isolates from the Asiatic (Siberia and Mongolia) and the African (Kenya and Egypt) continents, respectively. The majority (85.9%) of the genotypes were found in only one area, suggesting an endemic character of the Thioalkalivibrio strains. Furthermore, a correlation between fingerprint clustering, geographic origin and the characteristics of the lake of origin was found.

A short review: Limnological and paleolimnological researches in Mongolia carried out by Joint Russian-Mongolian expeditions

Mongolia-extensive inside-continental country, with an area of more than 1,500,000 km2. There are some mountain areas – Hangai and Hantai in the North, and Mongolian Altai in the West, and Gobi Altai – in the Center of the country. Altitude of the territory grow up to 1580 m above sea level in average. Therefore environment in this country may by consider as mountainous. Despite climate aridity, in the territory of Mongolia there are more than 3500 lakes with the area of a surface more than 0.1 km2. The largest lakes are: Ubsu-nuur-3350 km2, Huvsgul-2760 km2, Hyrgisnuur- 1407 km2, Buir-nuur-615 km2, Achit-nuur-297 km2. The special study of lakes in Mongolia began from 1921, when the Committee of Science of MPR was created, and after this, in the Academy of Sciences of the USSR the Mongolian Commission was formed. From that time on joint efforts of the Russian and Mongolian experts complex forwarding geological, palaeontological and geographical researches in territory of Mongolia began to be carried out.

Three-dimensional seismic structure of the upper mantle beneath the central part of the Eurasian continent

This work is a study of the upper-mantle seismic structure beneath the central part of the Eurasian continent, including the northern Mongolia, Altai and Sayan orogenic areas and the Baikal rift zone. Seismic velocity models are reconstructed using the inverse teleseismic scheme. This scheme uses information from earthquakes located within the study area recorded by the Worldwide Network. The seismic anomaly structure is obtained for different volumes in the study area that partially overlap one another. Special attention has been paid to the reliability of the results: several noise and resolution comparisons are made. The main results are as follows. (1) A cell structure of anomalies is observed beneath the Altai–Sayan region: positive, cold anomalies correspond to regions of recent orogenesis, negative anomalies are located beneath the depression of the Great Lakes in Mongolia and Hubsugul Lake. (2) A large negative anomaly is observed beneath the Hangai dome in Mongolia. (3) Strong velocity variations are obtained in a zone around Baikal Lake. A large negative anomaly is traced beneath the southern margin of the Siberian craton down to a depth of 700km. Contrasting positive anomalies (4–5 per cent) are observed at a depth of 100–300km beneath the Baikal rift. Our geodynamical interpretation of the velocity structure obtained beneath central Asia involves the existence of two processes in the mantle: thermal convection with regular cells, and a narrow plume beneath the southern border of the Siberian plate.