摘要
为探讨洞穴微生物沉积碳酸钙作用对洞穴沉积物的影响,利用传统生物学方法,采集贵州中西部地区石将军洞洞穴沉积物表面的微生物样品,结合洞穴监测数据和理化背景资料,利用B-4培养基和B-4C培养基对洞穴细菌进行筛选和纯化,分离出能沉积碳酸钙的菌种,观察和了解洞穴细菌形成的CaCO3晶体,应用X射线衍射分析仪(XRD)分析细菌形成的CaCO3晶体成分,并利用扫描电子显微镜(SEM)观察晶体结构特征。结果表明:1)在B-4培养基下微生物产生的碳酸钙晶体主要为方解石、球霰石和方解石混合物、球霰石,这种变化与培养基pH值的增幅相关;同时,在添加Mg离子的B-4C培养基下形成的碳酸钙晶体主要为方解石,此外,研究中并未检测到文石晶体。2)通过SEM扫描,发现微生物作用形成的碳酸钙晶体存在不规则六方体、柱状体、四方体层状、半球状等,这些晶体形态在化学作用系统下少见,多见于微生物作用形成的方解石。此外,晶体中微生物作用痕迹明显,微生物作用贯穿于整个沉积过程。
Microbes that play an important role in calcium carbonate deposition, but whose details are not well known, were studied. The Shijiangjun cave in the midwest of Guizhou province was chosen as the source for carbonate depositing bacteria separation as it has been investigated with respect to geology and geomorphology, and has been monitored for years for dripping water hydrogeochemical parameters. Samples of microorganisms collected from the cave sediment surface were separated by a B-4 culture medium, which is a common oligotrophic medium for carbonate depositing bacteria separation. B- 4C medium （ added Mg2~ ） was used for analysis of the Mg impact in the system. Fifty-eight strains were separated from eight samples, and finally, five strains that showed significant deposition phenomena were chosen for the liquid deposition test. The pH and Ca and Mg concentration in the system before and after the liquid deposition test were monitored. The mineral composition and morphology of the CaCO3 crystals filtered from the liquid deposition test system were analyzed using an X- ray diffraction analyzer （XRD） and a scanning electron microscope （SEM）, respectively. The XRD results show that three carbonate compositions were found in the B-4 medium liquid system （without Mg2＋） ： calcite, calcite-vaterite mixture, and vaterite. The composition seems to have been affected by the pH. There was no aragonite in the liquid system, and thus, the factors causing the formation of aragonite stalagmite need future research. Mg has been considered to be a participant in the formation of aragonite stalagmite, but it was not affected in this research. SEM pictures show the morphology of different carbonate crystals, including irregular hexagonal polytypes, cylindrical objects, square layers, and hemispherical types. These are rarely reported in the chemical system. Moreover, bacteria-shaped holes were observed on the crystal surface, implying the involvement of microbes in the deposition process.
出处
《生态学报》
CAS
CSCD
北大核心
2014年第8期2028-2038,共11页
Acta Ecologica Sinica
基金
国家自然科学基金项目(41001367)
国家自然科学基金项目(41301541)
中央高校基金(XDJK2013C091)
岩溶动力学重点实验室开放基金资助课题(KDL2010-01)
关键词
岩溶洞穴
微生物
沉积作用
PH值
碳酸钙
Karst caves
microorganisms
precipitation
pH
calcium carbonate
