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Cesium accumulation by bacterium Thermus sp. TibetanG7:hints for biomineralization of cesium-bearing geyserite in hot springs in Tibet,China

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chinese Science Bulletin 2007年第19期52卷 2680-2686页

作者： wang hailei1,2.3, {2. mianping1,2.3 & HUANG XiaoXing4 1 Institute of Mineral resources, chinese academy of geological sciences (CAGS), beijing 100037, China 2 r&d center for saline lake and epithermal deposits, CAGS, beijing 100037, China 3 Open Laboratory of saline lake resourses and Environment, CAGS, beijing 100037, China 4 Laboratory of Microbial resources, Institute of Microbiology, chinese academy of sciences, beijing 100081, China Institute of Mineral resources Chinese Academy of Geological Sciences (CAGS) Beijing China r&d {1. for {2. {2. and epithermal deposits CAGS Beijing China Open Laboratory of saline {1. resourses and Environment CAGS Beijing China Laboratory of Microbial resources Institute of Microbiology Chinese Academy of Sciences Beijing China

The bacterium Thermus sp. TibetanG7, isolated from hot springs in Tibet, China, was examined for the ability to accumulate cesium from solutions. Environmental conditions were simulated and the effects of pH, K+, Na+ and K+-regimes were then studied to determine the possible role of the bacterium in the formation of cesium-bearing geyserite around these hot springs. In despite of the inhibition of K+ and Na+, the bacterium Thermus sp. TibetanG7 revealed noticeable accumulation of cesium from solutions, with maximum accumulations of 53.49 and 40.41.μmol Cesium/g cell dry weight in Na+ and K+ inhibition experiments, respectively. The accumulation of cesium by this microorganism is rapid, with 40%―50% accumulated within the first 5 min. K+-deficient cells showed a much higher capacity of cesium accu- mulation compared with K+-sufficient cells. It is evident that the bacteria within the genus thermus play a significant role in the cesium assembly. The formation of cesium-bearing geyserite is also considered.

关键词：铯元素沉积物硅华生物矿化

Microbial Mats in Tibetan Hot Springs and their Contributions to the Cesium-bearing Geyserite Ore Formation

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Acta Geologica Sinica(English Edition) 2012年第1期86卷 166-173页

作者： wang {1. {2. mianping kong fanjing Institute of Mineral resources Chinese Academy of Geological Sciences(CAGS)Beijing 100037China Key Laboratory of saline {1. resources and Environment Ministry of Land and ResourcesBeijing 100037China r&d {1. for {2. {2. and epithermal deposits CAGSBeijing 100037China

Microbial mats, mainly dominated by filamentous algae Calothrix and Oscillatoria, are well developed in Tibetan hot springs. A great number of fossil microorganisms, which existed as algae lamination in thermal depositional cesium-bearing geyserite in this area, are identified as Calothrix and Oscillatoria through microexamination and culture experiments. These microbial mats show the ability to accumulate cesium from spring water to the extent of cesium concentration of 0.46-1.03% cell dry weight, 900 times higher than that in water, and capture large numbers of cesium-bearing opal grain. Silicon dioxide colloid in spring water replaces and fills with the organism and deposits on it to form algae laminated geyserite after dehydration and congelation. Cesium in the microbial mats and opal grain is then reserved in the geyserite. Eventually, cesium-bearing algae laminated geyserite is formed. Study on cesium distribution in geyserite also shows that cesium content in algae lamination, especially in heavily compacted algae lamination, is higher than in the opal layer. For geyserite with no algae lamination or other organism structure, which is generally formed in spring water with low silicon content, cesium accumulation and cesium-bearing opal grain assembled by the microbial mats are also indispensable. After the microbial mats accumulating cesium from spring water, silicon dioxide colloid poorly replaces and fills with the organism to form opal grain-bearing tremellose microbial mats. The shape and structure of the organisms are then destroyed, resulting in cesium-bearing geyserite with no algae lamination structure after dehydration and congelation. It is then concluded that microbial mats in the spring area contribute to the enrichment of cesium in the formation of cesium-bearing geyserite, and a biological genesis of the geyserite, besides of the physical and chemical genesis, is likely.

关键词： microbial mats cesium-bearing geyserite algae lamination biological genesis Tibetan hot spring

Progress and Prospects of Salt lake research in China

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Acta Geologica Sinica(English Edition) 2016年第4期90卷 1195-1235页

作者： zheng {1. ZHANG Yongsheng LIU Xifang NIE Zhen {2. fanjing QI Wen Jia Qingxian PU Linzhong HOU Xianhua wang hailei ZHANG Zhen {2. Weigang LIN Yongjie r&d {1. for {2. {2. and epithermal deposit CAGS Key Laboratory of saline {1. resources and Environment Ministry of Land and Resources

China has unique salt lake resources, and they are distributed in the east of Eurasian salt lake subzone of the Northern Hemisphere Salt lake Zone, mainly concentrated in the regions with modern mean annual precipitation lower than 500 mm. This paper preliminarily reviews the progress made in salt lake research in China for the past 60 years. In the research of Paleoclimate and paleoenvironment from salt lake sediments, a series of salts have been proposed to be indicators of paleoclimate, and have been well accepted by scholars. The chloride-sulfate depositional regions of the west Qaidam and the east Tarim have been revealed to be the drought center of China since the Quaternary, and more than 6 spreading stages of arid climate （salt forming） have been identified. Five pan-lake periods with highstands have been proved to exist during the late Quaternary on the Tibetan Plateau. In mineral resource prospecting and theories of the forming of salt deposits： the atlas （1.2.00000） of hydrochemical zoning of salt lakes on the Tibetan Plateau has been compiled for the first time, revealing the zonal distribution and transition from carbonate type to chloride type from south to north and presenting corresponding mineral assemblages for different type of salt lakes; several large continental salt deposits have been discovered and the theory of continental potash deposition has been developed, including the salt deposition in deep basins surrounded by high mountains, the mineral deposition from multistage evolution through chains of moderate or shallow lakes with multilevels, the origin of potassium rich brines in gravel layers, and the forming of potassium deposits through the inheriting from ancient salt deposits, thus establishing the framework of ＂Continental Potash deposition Theory＂; several new types of Mg-borate deposits have been discovered, including the ulexite and pinnoite bed in da Qaidam lake, Qinghai, the pinnoite and kurnakovite bed in Chagcam Caka, Tibet, th

关键词： progress in salt lake research in China salt lake {1. and paleoclimate salt deposition mineralization and salting theory of saline {1.s utilization and exploitation salt lake agriculture