Microorganism and silica in geothermal environments

1.通过对美国怀俄明州黄石国家公园热液区沉积物特征、沃茨和pH值的观测，以及硅质沉积物上和沉积物中硅质烧结物、沃茨、气体、伴生火山岩和微生物的取样，发现无定形二氧化硅的饱和度随着水的蒸发而增加，并控制着二氧化硅的沉积速率。硅质沉积物中铝含量与热水温度呈正相关。2.在诺里斯间歇泉盆地Cistern Spring不同温度条件下的硅质沉积物中发现了不同的细菌组合。此外，认识到二氧化硅沉积的速率与嗜热细菌的量相关。这与在地热发电厂的热水池中获得的结果一致，表明研究细菌控制二氧化硅沉积的机制是重要的。3.在黄石公园的调查中，不同的嗜热细菌在不同的温度条件下占主导地位。而硅质沉积物的组构和构造则可以反映地质历史时期的沉积环境。以九州火山区的一个0.5Ma的存款--Ikiryu烧结矿为例进行了研究。此外，还对地热发电厂管道中形成的硅质沉积物进行了精确的分析。4.对Beowawe间歇泉地区和汽船泉的非活性烧结体进行了研究，并采集了样品。这些样品的化学分析和结构研究正在进行中。

1.Observations of sedimentary features, measurements of temperature and pH of waters, and sampling of siliceous sinter, thermal waters, gases, associated volcanic rocks, and microbes on and in siliceous deposits were done in thermal areas of Yellowstone National Park, Wyoming, USA.A degree of saturation with respect to amorphous silica increases through evaporation along the drainage channel, and controls the rate of silica deposition. Aluminum concentrations in siliceous deposits shows positive correlation with temperatures of thermal waters.2.Various bacterial assemblages were found in siliceous deposits of different temperature conditions from Cistern Spring, Norris Geyser Basin. Also, it is recognized that the rate of silica deposition correlates with the amount of thermophillic bacteria. This concides with the result obtained from a thermal pool at a geothermal power plant, suggesting impoartanc of a study of the mechanism of bacterial control on silica deposition.3.During the investigation at Yellowstone it is shown that the different thermophillic bacteria dominate in different temperature conditions. Then the fabric and structure of siliceous deposits in geologic past can tell the depositional environments. Ikiryu sinter, 0.5 Ma old deposit in Kuju volcanic area, was investigated as a case study. In addition, siliceous deposits formed in pipes at geothermal power plants were precisely observed.4.Inactive sinters at Beowawe Geyser area and Steamboat Springs were studied and samples were collected. Chemical analysis and study of structures for these samples are in progress..