三株嗜盐古菌诱导形成白云石  

Dolomite Formation Facilitated by Three Halophilic Archaea

作　　者：段勇[1,2] 药彦辰 邱轩[1,2] 王红梅[1,2] Duan Yong;Yao Yanchen;Qiu Xuan;Wang Hongmei(State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430074,China;School of Environmental Studies,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]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43007 [2]中国地质大学环境学院,湖北武汉43007

出　　处：《地球科学（中国地质大学学报）》2017年第3期389-396,共8页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金项目(Nos.41502317;41572323;41130207)

摘　　要：白云石成因问题是地质学上长期悬而未决的难题之一.近年来,微生物诱导白云石沉淀逐渐成为白云石成因的重要理论之一,但其中微生物的作用机理远未探明.现生白云石主要分布于高盐环境,该环境中的优势菌群为嗜盐菌,包括嗜盐细菌和嗜盐古菌.因而此次选取三株嗜盐古菌Natrinema sp.J7-1、Natrinema sp.J7-3和Natrinema sp.LJ7,研究其诱导白云石沉淀的能力,并对比不同细胞浓度对白云石沉淀的影响,以期更深入地了解微生物在白云石形成中的作用.通过X射线衍射(XRD)检测沉淀物的物相,利用扫描电子显微镜(SEM)观察所得矿物形态,同时辅以能量色散谱分析(EDS)分析矿物的元素组成.实验结果表明三株嗜盐古菌皆可诱导球型、哑铃型、花椰菜型以及球形聚集体等白云石的形成,且在较高细胞浓度下诱导形成的矿物中白云石含量增多.分析表明细胞浓度的增加会导致细胞表面羧基含量的增加,从而为白云石的沉淀提供更多的成核位点,有利于Mg进入矿物晶格,从而诱导白云石沉淀,本结果进一步提高了对微生物白云石成因机理的认识.The dolomite formation problem has been puzzling geologists for a long time. Recently, microbial mediation is be- coming one leading theory for dolomite formation, though many details still remain poorly understood. The exclusive occur- rence of modern dolomite in saline environments leads to the investigation of the role of halophiles in dolomite formation. In this study, we focus on the effect of salinity and cell concentrations on dolomite mineralization with three halophilic archaea, Natrinerna sp.J7-1, Natrinerna sp.J7-3 and Natrinerna sp.LJ7. These halophilic archaea were collected and subject to the min- eral phase identification, morphology observation and element analysis via X-ray Diffraction （XRD） and Scanning Electronic Microscopy equipped with Energy Dispersive Spectrum （EDS）. Results confirm that all the strains used are capable of facilita- ting the dolomite formation under higher salinity conditions, and the yields of dolomite increase with cell concentration. Mor- phologically, dolomite is of the shape of sphere, dumb-bell, cauliflower and conglobulation. It is proposed that high salinity and high cell density will result in the more carboxyl groups on cell surface which can serve as nucleation sites for dolomite forma- tion, which is favorable for dolomite formation. The results offer more details about microbial role in dolomite formation and enhance our understanding about the mechanism.

关 键 词：白云石 嗜盐古菌 细胞浓度 盐度 矿物学. 

分 类 号：P571[天文地球—矿物学]