In situ conditions and interactions between microbes and minerals in fine-grained marine sediments: A TEM microfabric perspective
In situ conditions and interactions between microbes and minerals in fine-grained marine sediments: A TEM microfabric perspective
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细粒海洋沉积物中的原位条件以及微生物和矿物质之间的相互作用：TEM 微织物视角
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
P. Burkett
中科院分区：
文献类型：
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作者：
B. Ransom;R. H. Bennett;R. Baerwald;M. Hulbert;P. Burkett
摘要利用透射电子显微镜研究了细粒大陆边缘沉积物中的微生物及其胞外分泌物对沉积物矿物学和微组构的影响。采用的技术保留了生物有机和矿物成分的原位空间关系。在从有氧到厌氧的条件下，在第一米深的埋藏处拍摄了特征矿物微生物协会的显微照片。观察到单细胞原核生物、原核菌落和真核生物，以及能动、固着和捕食性物种。细菌细胞占主导地位的组合。最常观察到的矿物-生物相互作用是孤立的异养细菌细胞被粘土矿物包围或紧密结合。几乎无一例外地，细菌的外表面覆盖着分泌的胞外粘液组成的交联多糖纤维。这些原纤维的作用是将沉积物颗粒结合成相对坚固的微团聚体，直径约≤ 25 μm。这些胞外聚合物可以显着影响微生物和矿物之间的相互作用，以及通过沉积物的流体和溶解的水性物种的化学和物理运输。虽然孔隙水化学剖面从现场研究溶解铁和锰，没有密切的关联被发现之间的微生物成像和沉淀金属羟基氧化物或其他自生矿物，如通常报道的实验室培养。
Abstract Microbes, their exocellular secretions, and their impact on the mineralogy and microfabric of fine-grained continental margin sediments were investigated by transmission electron microscopy. Techniques were used that retained the in situ spatial relations of both bio-organic and mineralogical constituents. Photomicrographs were taken of characteristic mineral-microbe associations in the first meter of burial at conditions ranging from aerobic to anaerobic. Single-celled prokaryotes, prokaryotic colonies, and eukaryotic organisms were observed as were motile, sessile, and predatory species. Bacterial cells dominate the assemblage. The most commonly observed mineral-biological interaction was the surrounding, or close association, of isolated heterotrophic bacterial cells by clay minerals. Almost without exception, the external surfaces of the bacteria were covered with secreted exocellular slimes composed of cross-linked polysaccharide fibrils. These fibrils act to bind sediment grains into relatively robust microaggregates, roughly ≤ 25 μm in diameter. These exocellular polymers can significantly impact the interaction between microbes and minerals, as well as the chemical and physical transport of fluids and dissolved aqueous species through the sediment. Although pore water chemical profiles from the field sites studied have dissolved Fe and Mn, no close association was found between the microbes imaged and precipitated metal oxyhydroxides or other authigenic minerals, such as is commonly reported from laboratory cultures.