内蒙古吉布胡郎图诺尔盐湖厌氧菌对白云石形成的催化作用  

Catalytic Role of Anaerobic Bacteria in Dolomite Formation in Lake Jibuhulangtu Nuur, Inner Mongolia

作　　者：于娜 许杨阳 刘邓[1,2] 邱轩[2] 范奇高 王红梅[1,2] Yu Na;Xu Yangyang;Liu Deng;Qiu Xuan;Fan Qigao;Wang Hongmei(School of Environmental Studies,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430074 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430074

出　　处：《地球科学》2018年第A01期53-62,共10页Earth Science

基　　金：国家自然科学基金项目(Nos.41772362;41572323;41502317)

摘　　要：白云石的成因机制是地球科学领域备受关注的研究热点之一.地质微生物学家提出的"微生物白云石模式"为解答原生白云石沉积问题提供了新思路.具备孕育原生白云石能力的潮坪和盐湖被认为是研究微生物活动与白云石成因关系的天然实验室.以内蒙古吉布胡郎图诺尔盐湖湖底白云石的发现为研究切入点,尝试评估厌氧微生物对白云石生成的贡献,并回答硫酸根对其催化效能的影响.室内模拟实验表明厌氧菌群及隶属于嗜碱菌属的菌株JN-1均具备催化白云石形成的能力.X-射线粉晶衍射(XRD)分析显示,微生物诱导的矿物产物为无序白云石.扫描电镜(SEM)结果揭示,微生物成因白云石的形貌随培养时间的延长从亚微米球状体转变为微米尺寸的椭球体和哑铃体.此外,模拟实验还证实硫酸根对微生物催化白云石的效能没有抑制作用.以上结果对我们正确认识硫酸根在白云石形成中的作用和促进白云石成因的深入研究具有重要理论意义.Much attention has been attracted to understand the formation mechanism of dolomite, a long-standing problem in earth sciences. A microbial dolomite model, proposed by geomicrobiologists, has been considered to provide new insights into this old enigma. Although authigenic dolomite is rare in modern marine sediments, the occurrence of dolomite can be found in some hypersaline environments（e.g., tidal flats and saline lakes）. Therefore, these highly-evaporating environments are believed as nature laboratory for probing the role of microbe in dolomite formation.In this study, it reports a new discovery of modern dolomite in Lake Jibuhulangtu Nuur, a saline lake in Inner Mongolia. In order to address whether anaerobic microbes are involved in dolomite precipitation in this lake and whether sulfate ion has an impact on this reaction, precipitation experiments using microbial enrichment and pure culture were performed in lab. Our results show that both microbial consortium and strain JN-1 were capable of inducing dolomite precipitation. There were no ordering reflections in X-ray diffraction patterns, thus indicating that these biogenic dolomites were highly disordered. The observations by using scanning electron microscopy further show that the crystal morphology of biogenic dolomite developed during incubation period. In the early incubation stage, dolomite particles were sub-micron sized spherulites, however, they transformed into larger spheroids and dumbbell-shaped crystals. Furthermore, it seemed that sulfate had little effect on microbial dolomite formation. Our findings would be of significance for providing the basic data for the interaction between sulfate ions and dolomite formation, and improving our understanding of the formation mechanism of dolomite.

关 键 词：微生物白云石模式 无序白云石 微生物矿化 生物成因矿物 嗜盐微生物 矿物学 

分 类 号：P593[天文地球—地球化学]