Geomicrobiology as a New Tool for Exploration of Marine Gas Hydrates
SU Xin1,CHEN Fang2,ZHANG Yong1,WANG Yuan-yuan1,JIAO Lu1,JIANG Hong-cheng1,DONG Hai-liang1,3(1.School of Marine Sciences,China University of Geosciences,Beijing 100083,China;2.Guangzhou Marine Geological Survey,Guangzhou,Guangdong 510760,China;3.Department of Geology,Miami University,Oxford,Ohio 45056,USA)
For exploration of marine gas hydrates,three major techniques were commonly used for marine geological survey and for indication of existence of gas hydrates: geophysical techniques,geochemical techniques,and geological techniques.It is the trend to employ advanced and multi-proxy or techniques to determine and identify the existence and distribution of marine gas hydrates.This trend provides both of chance and challenge for using geomicrobiological techniques in this field.Marine gas hydrates were formed in deep sea sediments under high pressure and low temperatures.Abundant and a variety of microbes are living in the gas-hydrate-bearing sediments and several groups of microbes play significant roles in formation and decomposition of gas hydrates.For example,methanogens produce methane as a metabolic byproduct under anoxic conditions in deep sediments,providing biogenic methane sources for formation of gas hydrate;on the other hand,methanotrophic microbes rely on methane as their sole carbon and energy sources,consuming methane released from gas hydrates through complex processes of anaerobic methane oxidation,thus showing very sensitive response to variation of methane flux in sediments.This paper introduced several cases for geomicrobiological techniques used in exploration of gas and gas hydrates:(1)microbial oil survey technique(MOST);(1) Analysis of abundance of microbial cells(microbial counts)in correlation to concentration of methane in gas-hydrate-bearing sediments;(3)studies on microbial communities(microbial community analysis) in correlation to distribution of gas hydrates in sediments.It is seen that MOST and Microbial counts can be used as prospecting techniques during marine geological survey for gas hydrates,while techniques of microbial community analysis and biogeochemical analysis are of importance for identification of existence of gas hydrates in sediments and the sources of methane in gas hydrates.
【Fund】： 国家重点基础研究发展计划项目(2009CB219502);; 国土资源部公益性行业科研专项(200811014-02);; 中国地质调查局基础调查项目(GZH200200203-02-01)
【CateGory Index】： P744.4
【CateGory Index】： P744.4