Ultrastructural Evidence for a Novel Accumulation of Ca in a Microbial Mat from a Slight Acidic Hot Spring  

作　　者：PENG Xiaotong ZHOU Huaiyang YAO Huiqiang, LI Jiangtao WU Zijun 

机构地区：[1]State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China

出　　处：《Acta Geologica Sinica(English Edition)》2010年第3期624-631,共8页地质学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.40532011,40403004,and 40473032).

摘　　要：Microbial mats are ecosystems that can control or induce the precipitation of calcium（Ca） carbonate on Earth through geological time.In the present study,we report on a novel accumulation of Ca,together with iron（Fe）,in a microbial mat collected from a slight acidic hot spring（pH=5.9） in south China.Combining an array of approaches,including environmental scanning electron microscopy,X-ray microanalysis,transmission electron microscopy,and selected area electron diffraction,we provide ultrastructral evidence for amorphous acicular aggregates containing Ca and Fe associated with cyanobacteria precipitating in the microbial mats.Cyanobacterial photosynthesis and exopolymeric organic matrixes are considered to be responsible for the precipitation of Ca.These amorphous acicular aggregates might imply the early stage of calcification occurring in microbial mats.Ca and Fe coprecipitation indicates another potential important way of inorganic element precipitation in hot spring microbial mats.Our results provide insight into the possible mechanism of cyanobacterial calcification and microfossil preservation in slight acidic hot spring environments.Microbial mats are ecosystems that can control or induce the precipitation of calcium（Ca） carbonate on Earth through geological time.In the present study,we report on a novel accumulation of Ca,together with iron（Fe）,in a microbial mat collected from a slight acidic hot spring（pH=5.9） in south China.Combining an array of approaches,including environmental scanning electron microscopy,X-ray microanalysis,transmission electron microscopy,and selected area electron diffraction,we provide ultrastructral evidence for amorphous acicular aggregates containing Ca and Fe associated with cyanobacteria precipitating in the microbial mats.Cyanobacterial photosynthesis and exopolymeric organic matrixes are considered to be responsible for the precipitation of Ca.These amorphous acicular aggregates might imply the early stage of calcification occurring in microbial mats.Ca and Fe coprecipitation indicates another potential important way of inorganic element precipitation in hot spring microbial mats.Our results provide insight into the possible mechanism of cyanobacterial calcification and microfossil preservation in slight acidic hot spring environments.

关 键 词：CYANOBACTERIA CALCIFICATION hot spring microbial mat microfossil preservation 

分 类 号：Q959.223.5[生物学—动物学] X703[环境科学与工程—环境工程]