微生物引起的地席是能控制或导致钙(Ca ) 的降水的生态系统整个地质的时间在地球上的碳酸盐。在现在的学习，我们在 Ca 的新奇累积上报导，和铁(Fe ) ，在从在华南的一个细微酸的温泉(pH=5.9 ) 收集的微生物引起的地席。联合一连串的途径，包括环境扫描电子显微镜学， X 光检查微量分析，传播电子显微镜学，和选择区域电子衍射，我们为包含与 cyanobacteria 在微生物引起的地席猛抛联系的 Ca 和 Fe 的非结晶的针状的总数提供 ultrastructral 证据。器官的矩阵被考虑为 Ca 的降水负责的 Cyanobacterial 光合作用和 exopolymeric。这些非结晶的针状的总数可能暗示发生在微生物引起的地席的石灰化的早阶段。Ca 和 Fe 一起沉淀在温泉显示无机的元素降水的另一个潜在的重要方法微生物引起的地席。我们的结果在细微酸的温泉环境提供卓见进 cyanobacterial 石灰化和微化石保藏的可能的机制。
PENG Xiaotong ZHOU Huaiyang YAO Huiqiang, LI Jiangtao WU Zijun
用ICP-MS对取自Juan de Fuca洋脊Endeavour段5块热液硫化物样品的13个分析样进行了稀土元素(REE)测试。结果显示该区硫化物样品的REE含量较低(0.35～14.8μg/g),所有样品的REE球粒陨石标准化分布模式均表现出Eu正异常和LREE富集的特征,表明硫化物中的REE来自热液。不同喷口硫化物的REE含量变化较大,同一块状硫化物不同部位的含量也有较大差异,主要是由于硫化物形成过程中,热液和海水的混合不均一性以及不同矿物沉淀和(或)溶解的结果。硫化物REE的分布特征主要受热液的影响,烟囱内外层Eu正异常的变化主要受矿物组成和物理化学条件的控制。
This paper deals with the bio-oxidation processes by Acidithiobacillus ferrooxidans of pyrite, chalcopyrite and pyrrhotite. Our experimental results show distinctive bio-oxidation characteristics for the three sulfide minerals. In the presence of A. ferrooxidans, the sulfide oxidation rates generally decrease in the order of pyrrhotite, chalcopyrite and pyrite. The pH during bio-oxidation of pyrite tends to decrease as a whole, whereas a rise-fall pattern was recorded for both chalcopyrite and pyrrhotite in their pH variations. No deposition was observed during the bio-oxidation of pyrite, suggesting a possible link to lower pH value in the process. However, large amounts of jarosite and element sulfur were determined in the bio-oxidation processes of chalcopyrite and pyrrhotite. A. ferrooxidans individuals were found directly as attachments to erosion pits on the smooth surface of pyrite. The erosion pits are similar to the bacterium in shape and length, and thus are probably products of dissolution of organic acid secreted by the cells on the mineral surface. More complicatedly, biofilm exists on the surfaces of chalcopyrite and pyrrhotite. This type of structured community of A. ferrooxidans is enclosed in the extracellular polymeric substances (EPS), and covered with the deposition generated in the bio-oxidation processes of chalcopyrite and pyrrhotite. Different bio-oxidation processes of pyrite, chalcopyrite and pyrrhotite may be linked mainly to characteristics of individual minerals and the pH in the reaction solution of the bio-oxidation system.
Microbial mats in two hot springs in South China were sampled for the research of mineralization of microbes and its mechanism by the methods of geology and modern biology. The results show that hot spring microbes have the key capability for enrichment of Si, Al, Fe, Ca and other elements, and the microbes are also crucial for the formation of SiO2, CaCO3, clay and so on. The extracellular polymeric substances (EPS) play important roles in the process of mineralization of hot spring microbes, which mainly takes place in the layer of EPS outside cell wall or sheath of cyanobacteria. The sheath outside cell wall, which keeps the normal metabolism of cyanobacteria during the process of mineralization on its surface, is also considerable for the biomineralization of cyanobacteria. According to structure and mineralization characteristics of two microbial mats, the process of mineralization can be divided into three stages, namely, early surface mineralization, middle degradation mineralization, and late des- quamation of mineral. The above conclusions are significant for comprehension of the process of mineralization, the process of deposition and the preservation of microfossil in modern and ancient extreme environments.
PENG XiaoTong ZHOU HuaiYang WU ZhiJun JIANG Lei TANG Song YAO HuiQiang
