Nanoscale study of As biomineralization in an acid mine drainage system
Nanoscale study of As biomineralization in an acid mine drainage system
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DOI：
10.1016/j.gca.2008.05.046
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发表时间：
2008-08-15
影响因子：
5
通讯作者：
Brown, G. E., Jr.
中科院分区：
文献类型：
--
作者：
Benzerara, K.;Morin, G.;Brown, G. E., Jr.
空间和季节变化的Fe（II）和As（III）的氧化以前已经记录在卡努勒（加尔，法国）酸性矿山排水（AMD）的散装分析。这些变化可能与土著As（III）-和Fe（II）-氧化细菌生活在丰富的Carnoules水的活性的变化。这些细菌的活性确实在该地点螯合砷的固相的性质和组成中起着重要作用。为了更好地了解微生物与Fe和As在Carnoules AMD中的相互作用，我们结合了透射电子显微镜（TEM）和扫描透射X射线显微镜（STXM），以高空间和能量分辨率收集近边X射线吸收精细结构（NEXAFS）光谱，并在30-50 nm尺度下进行高空间分辨率成像。在C K-边，Fe L-2，L-3-边和As L-2，L-3-边进行光谱显微镜检查，这使我们能够定位活的和/或矿化的细菌细胞，并表征这些细胞附近的Fe和As氧化态。TEM被用于对相同区域进行成像，通过电子衍射和EDXS分析提供更高分辨率的图像和互补的晶体学和组成信息。这种方法提供了独特的信息发生在一个复杂的微生物群落在AMD环境中的非均质地球化学过程中的微米和亚微米尺度。细菌细胞在Carnoules AMD经常与矿物沉淀，并观察到各种生物矿化模式。虽然许多矿物沉淀物与细菌细胞无关，但它们与无处不在的有机碳有关。最后，在Carnoules AMD中观察到丰富的生物矿化有机囊泡。这种囊泡在过去的高度矿化的极端环境中可能被忽视，并且可能是这种环境中常见的生物矿化过程中的重要组成部分。(C)2008爱思唯尔有限公司版权所有。
Spatial and seasonal variations of the oxidation of Fe(II) and As(III) have been previously documented in the Carnoules (Gard, France) Acid Mine Drainage (AMD) by bulk analyses. These variations may be correlated with the variations in the activity of indigenous As(III)- and Fe(II)-oxidizing bacteria living in the As-rich Carnoules water. The activity of these bacteria indeed plays an important role in the nature and composition of the solid phases that sequester arsenic at this site. In order to better understand the interactions of microbes with Fe and As in the Carnoules AMD, we combined Transmission Electron Microscopy (TEM) and Scanning Transmission X-ray Microscopy (STXM) to collect near-edge X-ray absorption fine structure (NEXAFS) spectra at high spatial and energy resolution and to perform high spatial resolution imaging at the 30-50 nm scale. Spectromicroscopy was performed at the C K-edge, Fe L-2,L-3-edge, and As L-2,L-3-edge, which allowed us to locate living and/or mineralized bacterial cells and to characterize Fe and As oxidation states in the vicinity of those cells. TEM was used to image the same areas, providing higher resolution images and complementary crystallographic and compositional information through electron diffraction and EDXS analysis. This approach provides unique information on heterogeneous geochemical processes that occur in a complex microbial community in an AMD environment at the micrometer and submicrometer-scale. Bacterial cells in the Carnoules AMD were frequently associated with mineral precipitates, and a variety of biomineralization patterns were observed. While many mineral precipitates were not associated with bacterial cells, they were associated with pervasive organic carbon. Finally, abundant biomineralized organic vesicles were observed in the Carnoules AMD. Such vesicles may have been overlooked in highly mineralized extreme environments in the past and may represent an important component in a common biomineralization process in such environments. (C) 2008 Elsevier Ltd. All rights reserved.