论文部分内容阅读
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 cause of dolomite is one of the long-standing problems in geology .In recent years, mica-induced dolomite precipitation has gradually become one of the important theories of the cause of dolomite, but the mechanism of action of the microorganisms is far from proven. Distribution in the high salt environment, the dominant bacteria in this environment for the halophilic bacteria, including halophilic bacteria and halophilic archaea.Therefore, the selection of three strains of halophilic archaebacteria Natrinema sp.J7-1, Natrinema sp.J7- 3 and Natrinema sp.LJ7 to study the effect of different concentrations of dolomite on the precipitation of dolomite in order to better understand the role of microorganisms in dolomite formation.According to XRD The morphology of the minerals was observed by scanning electron microscopy (SEM) and the elemental composition of the minerals was analyzed by energy dispersive spectroscopy (EDS). The results showed that all the three halophilic archaea could induce the globular, dumbbell Type, cauliflower type, and spherical aggregates, and dolomite content is increased in minerals induced at higher cell concentrations. The analysis shows that an increase in cell concentration leads to a decrease in cell surface carboxyl The results show that dolomite can be precipitated in the presence of more nucleation sites, which is favorable for Mg to enter into the crystal lattices of the minerals and induce dolomite precipitation. This result further enhances the understanding of the genetic mechanism of microbial dolomites.