Journal Biology 2004 1

Mongolian Journal of Biological Sciences 2003 Vol. 1(2): 37-42 Structure and Functioning of Microbial Community of Mineral Springs in Central Asia Namsaraev B.B.1, Barkhutova D.D. 1, Danilova E.V. 1, Dagurova O.P. 1, Namsaraev Z.B.2, Balzhiin Tsetseg3, Ayush Oyuntsetseg4 1Institute of General and Experimental Biology, Siberian Branch of the Russian Academy of Sciences, Ulan- Ude, Russia e-mail: [email protected] 2Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia 3Institute of Biology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia 4Faculty of Biology, National University of Mongolia, Ulaanbaatar 210646, Mongolia, e-mail: oyun_a@ num.edu.mn Abstract The microbial mats of different types of springs in Central Asia (Zabaikalye and Mongolia) are described. The species diversity of mat-formed phototrophic bacteria was determined. The rates of microbial destruction processes (sulfate reduction and methane formation) were measured. An important role of bacteria and algae in the formation of mineral water composition was shown. Key words: bacterial processes, Central Asia, microbial mats, mineral springs Introduction kilometers of the deep kainozoii breaks. The origin of carbonated mineral springs is connected with Functional diversity of microbial communities carbonate and silicate rocks in zones of young depends on chemical composition of waters and volcanic activity. rocks. The electrons acceptor contents, biogenous Hydro-chemical and microbiological research elements and other substances influence microbial has been conducted in the mineral springs of diversity and microbial activity (Zavarzin, 1984). Zabaikalye and Mongolia (Barkhutova et al., 1998; At the same time microorganisms play an active Abidueva et al., 1999; Barkhutova et al., 2003). part in formation of qualitative and quantitative The location of springs is shown in Fig. 1. Particular composition of natural waters, as a result of their attention in this research has been paid to estimation high biochemical potential and large numbers. of geo-chemical activity of microorganisms, to Aerobic and anaerobic, autotrophic and determination of physiological group numbers, and heterotrophic bacteria, fungi and algae take part in to the study of species diversity of bacteria and biogeochemical processes taking place in algae. underground and surface waters. Microorganisms are the main catalysts of multistage processes of Methods production, destruction and transformation of organic material, formation and consumption of Samples were taken from 21 springs in gases and synthesis of secondary metabolites. Zabaikalye and Mongolia. Samples were taken Geological history, geo-structural peculiarities from the spring basin (water body), from the brook of territory, chemical composition of rocks, running out from the spring and from giffon formed geothermal and climatic conditions cause on the surface of the water. Water samples and silt widespread mineral waters in Central Asia where were taken from 0.1-0.5m; samples of mat were various types of mineral spring have been taken from river sides and small lagoons. Water determined. They are subdivided into nitrogen, temperature was taken with an electric sensor carbonaceous and methane springs as well as hot, thermometer “Prima”, pH with portative precision warm and cool groups (Tkachuk et al, 1962; pH-meter PRO, redox potential with a redox Pinneker, 1980). Nitric springs form as a result of potential tester ORP and salinity with a portative heat occurrence with infiltrated waters from 2-3 tester-conduct-meter TDS-4. Concentrations of 37 http://dx.doi.org/10.22353/mjbs.2003.01.16 B.B. Namsaraev et al. Fig. 1. Location scheme of studied mineral springs (Zabaikalye and Mongolia regions) 1 – Alla, 2 – Kuchiger, 3 - Bolshaya Rechka, 4 – Garga, 5 – Seiya, 6 – Uro, 7 – Umkhei, 8 – Bakhlaita, 9 – Khalyuta, 10 – Gegetui, 11 – Zmeyinaya, 12 - Sukhaya Zagza, 13 - Khoito Gol, 14 – Shumak, 15 - Gadan Gembe, 16 – Zhoigon, 17 – Suduntui, 18 – Alkhanai, 19 – Erdenet, 20 – Khuzhirta, 21 - Devsen Bulag carbonates, sulfides and sulfates were measured springs with a high concentration of sulfide, such by colorimeter (Kuznetsov et al., 1989). Microbial as Alla, Umkhei, Zmeyinaya, Kuchiger, Devsen process rate was determined by radioisotope Bulag and Bakhlaita. High methane concentration method (Wainshtein et al., 1988). of Sukhaya Zagza spring is favorable for activity of methanotrophic bacteria. Perennial thick mats Results with a thickness of 2-7 cm are found in hot brooks of Seiya, Garga, Alla and Khuzhirta springs. At the Water temperature in the springs under study outlet of Alla spring, situated on the left side at o was 1.2-76.20C (Table 1). Maximum water 58 C microbial mat is not formed, on the bottom temperature was in Alla spring and minimum in there is a thin brown film covering black sand and Gegetui spring. Salinity of water in the springs was silt, which provides evidence of active sulfate-re- 0.1-1.55 g/l. Maximum salinity was measured in ducing bacteria. o Zhoigan spring. The pH values varied from 2.8 At 49 C cyanobacterial mats grow and the color (Erdenet spring) to 9.6 (Alla spring). Hydrogen gradually changes from bright green to dark yel- sulfide concentration was 0.46-45.5 mg/l. The low. When plating from the mat, Heliobacter sp., highest values were observed in water from Alla Chromatium sp., Thiocapsa sp. and Desulfobacter and Zmeinaya springs. sp. were isolated. At 35oC Thiothrix sp. and In spring outlets and brooks microbial mats have Cyanobacteria (Phormidium sp.) develop, attach- been noticed (Tables 2-3). Cyanobacterial, green ing to stones. and purple mats grow at temperatures below 60oC. At 65-790C in the spring, situated on the right- Sulfur mats have been noticed in hot and cold bank, there are no visible bacterial communities. 38 Microbial community of mineral springs in Asia It can be explained by the combined influence of 3 have been found in the brook. Cyanobacterial environmental factors: high temperature, pH and communities appear at 13.5oC and pH 8.2 and sulfide existence. However, when plating sand sam- decrease of hydrogen sulfide concentration to 5 ples from this mat culture Chloroflexus aurantiacus mg/l. The total productivity of mat in thermal was isolated. 70 cm downstream from the spring springs increases when temperature decreases. So, outlet a dark-brown mat is developing, formed by in Alla spring the total productivity increases from Chloroflexus aurantiacus and Termus ruber. At 360 mg C/ (m2 day) in the point BG-8 (temperature 590C a thick cyanobacterial mat grows, 65oC) to 840 mg C/(m2 day) (temperature 45oC). In Chloroflexus dominating. Thickness of this mat Garga spring the rate of oxygenous photosynthesis reaches 3-4 cm. Under microscope Chloroflexus is 203 mg C/(m2 day), while the rate of anoxygenous aurantiacus dominates in the upper layer of the photosynthesis is 50 mg C/(m2 day). On terminal mat; cyanobacteria have not been recorded. In stages of organic matter destruction participates deeper layers Synechococcus sp. appears. When sulfate-reducing acetogens, methanogens and temperature decreases cyanobacteria begin to methanotrophs (Table 4). Their activities primarily dominate. At 40oC layers of purple bacteria appear. depend on sulfate concentration in the spring water. At 35oC the color of the mat changes. The surface In Alla, Zmeyinaya and Garga springs, sulfate becomes covered with a white layer of sulfur bac- concentration is not high and its maximum was Table 1. Physical and chemical characteristics of mineral springs in Central Asia Spring Situation T0C pH Salinity g/l Type Alla Barguzin range, Buryatia 76.2 9.6 0.24 Nitric Kuchiger -“- 43.0 9.8 0.6 Nitric Bolshaya -“- 74.5 10.2 0.39 Nitric Rechka Garga Ikatskii range 72.7 7.9 1.0 Nitric Seiya -“- 50.3 9.6 0.32 Nitric Uro -“- 67.2 8.7 0.25 Nitric Umkhei The upper Barguzin river 47.6 9.1 0.45 Nitric Bakhlaita Sulfide- Valley of Kizhinga river 5.0 8.2 0.5 hydrogen Khalyuta Range Khamar Daban 4.2 6.8 0.15 Carbonated Gegetui -“- 1.2 7.3 0.24 Carbonated Zmeinaya Chivirkuiski Bay, Lake Baikal shore 52.3 8.9 0.43 Nitric Sukhaya Zagza Lake Baikal shore 48.0 8.4 0.51 Methane Khoito Gol The upper Sentsi river, Eastern Sayans 34.0 8.3 0.62 Carbonated Shumak The upper Shumak river, Eastern Sayans 34.0 7.2 0.56 Carbonated Gadan Gembe Mountain Tengesiin Dabaan, Eastern Sayans 20.8 6.5 0.56 Carbonated Zhoigon Valley of Arzham-Khem river, Tiva 38.5 8.2 1.55 Carbonated Suduntui The upper Suduntui river, Aginski region 3.7 6.0 0.25 Carbonated Alkhanai Spurs of the mountain Alkhanai, Aginski 3.0 6.7 0.34 Carbonated region Erdenet Range Burengiin nuruu, Orkhon aimak, Acid without 11.6 2.8 0.7 Mongolia gas Khuzhirta The upper Orkhon river, Uburkhangai 49.1 9.2 0.24 Nitric district, Mongolia Devsen Bulag Sulfide- Erden Sant somon, Tov aimak, Mongolia 4.2 7.1 0.4 hydrogen teria. Under this layer cyanobacteria and beneath noticed in Zmeyinaya spring. Sulfate reduction rate this purple bacteria grow. At lower temperatures in the studied probes was 0.01-10.4 mg S/(kg day). microbial mats are not found. For 20 m downstream Maximum rate was determined in the mats of colorless sulfuric bacteria Thiothrix develops Zhoigon spring. High values for this process have (Barkhutova et al., 1998). been measured in mat samples from Khoito Gol, In the brook of the hydrogen sulfide spring Garga and Zmeyinaya spring. In the spring of Devsen Bulag the layer of elemental sulfide is seen Barguzin valley and Eastern Sayans part of the as a yellowish film on stones and a white film is organic matter is used for sulfate restoration. A low noticed on the water surface. Sulfur mats Thiothrix rate of sulfate reduction has been measured in the 39 B.B.

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