Microbial communities of the stratified soda Lake Doroninskoe (Transbaikal region)

Горленко, В. М.; Buryukhaev, S. P.; Matyugina, E B; Борзенко, С. В.; Намсараев, З. Б.; Bryantseva, I. A.; Boldareva, E. N.; Sorokin, Dimitry Y.; Намсараев, Б. Б.

doi:10.1134/s0026261710030161

Cited by 27 publications

(9 citation statements)

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“…Lake Doroninskoe represents an exception among the lakes studied, which are holomictic and fully aerobic, as it regularly develops seasonal stratification lasting from spring till late summer (Gorlenko et al , 2010). The diurnal changes in the BChl a fluorescence signal were followed at the aerobic surface layer for 42 h. Similar to lake Khilganta, the signal exhibited strong diurnal changes, with the maxima recorded in the early morning and the minima in the evening (Fig.…”

Section: Resultsmentioning

confidence: 99%

High abundances of aerobic anoxygenic phototrophs in saline steppe lakes

Medová¹,

Boldareva²,

Hrouzek³

et al. 2011

FEMS Microbiology Ecology

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We studied the distribution of anoxygenic phototrophs in 23 steppe lakes in the Transbaikal region (Russia), in Uzbekistan (Central Asia) and in the Crimean peninsula (Ukraine). The lakes varied in their mineral content and composition (salinities from 0.2 to 300 g L À1 ). The Transbaikal lakes were alkaline (pH 4 9), with high amounts of soda. The Uzbek and Crimean lakes were more pH neutral, frequently with high amounts of sulfates. The presence of anoxygenic phototrophs was registered by infrared epifluorescence microscopy, infrared fluorometry and pigment analyses. In mostly shallow, fully oxic lakes, the anoxygenic phototrophs represented 7-65% of the total prokaryotes, with the maxima observed in Transbaikal soda lakes Gorbunka (32%), Khilganta (65%), Zanday (58%) and Zun-Kholvo (46%). Some of the lakes contained over 1 mg bacteriochlorophyll L À1 .In contrast, only small amounts of anoxygenic phototrophs were present in highly mineralized lakes ( 4 100 g total salts L À1 ); Borzinskoe, Tsagan-Nur (Transbaikal), Staroe (Crimea) and in the residual part of the south-west Aral Sea (Uzbekistan). The oxic environment and the specific diurnal changes of bacteriochlorophyll concentration observed suggest that the phototrophic community was mostly composed of aerobic anoxygenic phototrophs. The high abundances and bacteriochlorophyll concentrations point to an important role of aerobic anoxygenic phototrophs in the habitats studied.

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Section: Resultsmentioning

confidence: 99%

High abundances of aerobic anoxygenic phototrophs in saline steppe lakes

Medová¹,

Boldareva²,

Hrouzek³

et al. 2011

FEMS Microbiology Ecology

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“…This group was discovered in the coastal waters of Japan in the late 1970s (8,29) and was later recognized as an important part of marine microbial communities (12,17,21,37). The presence of AAPs was also reported in a number of other environments: freshwater (23,28), soda and saline lakes (7,22,24), soils (4,13), and acid hot springs (11).…”

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confidence: 95%

Influence of Light on Carbon Utilization in Aerobic Anoxygenic Phototrophs

Hauruseu

Koblížek

2012

Appl Environ Microbiol

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bAerobic anoxygenic phototrophs contain photosynthetic reaction centers composed of bacteriochlorophyll. These organisms are photoheterotrophs, as they require organic carbon substrates for their growth whereas light-derived energy has only an auxiliary function. To establish the contribution of light energy to their metabolism, we grew the phototrophic strain Erythrobacter sp. NAP1 in a carbon-limited chemostat regimen on defined carbon sources (glutamate, pyruvate, acetate, and glucose) under conditions of different light intensities. When grown in a light-dark cycle, these bacteria accumulated 25% to 110% more biomass in terms of carbon than cultures grown in the dark. Cultures grown on glutamate accumulated the most biomass at moderate light intensities of 50 to 150 mol m ؊2 s ؊1 but were inhibited at higher light intensities. In the case of pyruvate, we did not find any inhibition of growth by high irradiance. The extent of anaplerotic carbon fixation was detemined by radioactive bicarbonate incorporation assays. While the carboxylation activity provided 4% to 11% of the cellular carbon in the pyruvate-grown culture, in the glutamate-grown cells it provided only approximately 1% of the carbon. Additionally, we tested the effect of light on respiration and photosynthetic electron flow. With increasing light intensity, respiration decreased to approximately 25% of its dark value and was replaced by photophosphorylation. The additional energy from light allows the aerobic anoxygenic phototrophs to accumulate the supplied organic carbon which would otherwise be respired. The higher efficiency of organic carbon utilization may provide an important competitive advantage during growth under carbon-limited conditions.

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“…It is characterized by an alkaline values of рН (9.72), a relatively elevated water and sediments mineralization (32.3 g/l) and a permanent chemocline at a depth of 3.0-3.75 m separating the aerobic epilimnionfrom the anaerobic, sulfidogenichypolimnion (Zamana, Borzenko, 2007);those positively correlate with the distribution of bacteria (Gorlenko et al, 2010). Samples of water were collected in March 2013, filtered through 0.22 um polycarbonate filters (Millipore), and stored at 20°C before further treatment.…”

Section: Object and Methodsmentioning

confidence: 99%