权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Microbial Ion Accumulation and Mineral Formation in the Weathering Environment

风化环境中微生物离子的积累和矿物质的形成

基本信息

批准号：
12640472
负责人：
KAWANO Motoharu
金额：
$ 2.37万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Bacteria are the earlist life of the Earth, appearing within the first billion years of the Earth's history. Scince then, bacteria have been widely distributed on the Earth's surface including soils, weathered rocks and sediments, lakes, rivers, and oceans. Geobiological studies have shown that bacteria play an important role in elemental circulation over the Earth's surface, especially through the interactions of cell wall surfaces with dissolved ions in the external environments producing various secondary minerals such asoxides, sulfides, carbonates, and silicates. This study focused on such bacteria - mineral interaction in various weathered sediments (Ito pyroclastic fllow deposit, Akahoya volcanic ash deposit, Kaimondake volcanic ash deposit, Sakurajima volcanic ash deposit) distributed in Kagoshima prefecture, Southern Kyushu, Japan, using XRD, SEM, TEM, and EDX. Results of this study indicated that these weathered sediments contain great amounts of spherical to rod-shaped bacteria (10^7〜10^8 cells/g) covered or decorated with poorly ordered secondary minerals exhibiting aggregates of fine fibrous materials. EDX confirmed that the secondary minerals consisted mainly of Al, Si, and Fe, corresponding to chemical compositions among allophane, nontronite, and chamosite. These chemical characteristics are apparently different from those of abiogenie secondary products such as allophane and halloysite co-existing with the products on the bacterial surfaces. This strongly indicates that the most of bacteria in the weathered sediments acculucate Al, Si, and Fe ions and produce silicate minerals on their cell surfaces.

细菌是地球最早的生命，出现在地球历史的头10亿年内。从那时起，细菌广泛分布在地球表面，包括土壤、风化岩石和沉积物、湖泊、河流和海洋。地球生物学研究表明，细菌在地球表面的元素循环中发挥着重要作用，特别是通过细胞壁表面与外部环境中的溶解离子相互作用，产生各种次生矿物，如氧化物、硫化物、碳酸盐和硅酸盐。利用X射线衍射仪、扫描电子显微镜、透射电子显微镜和能谱分析等手段，研究了日本九州南部鹿儿岛县不同风化沉积物(伊藤火山碎屑岩沉积、赤浩屋火山灰沉积、凯蒙达克火山灰沉积、樱岛火山灰沉积)中细菌与矿物的相互作用。研究结果表明，这些风化沉积物中含有大量的球形至杆状细菌(107~108个/g)，覆盖或装饰着排列不整齐的次生矿物，表现为细纤维物质的聚集体。EDX分析表明，次生矿物主要由Al、Si和Fe组成，与尿磷矿、非钠辉石和绿泥石之间的化学成分相对应。这些化学性质明显不同于与细菌表面共存的非生物次生产物如尿磷矿和埃洛石。这有力地表明，风化沉积物中的大多数细菌聚集了Al、Si和Fe离子，并在其细胞表面产生了硅酸盐矿物。