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Preservation of bacterial microfossils of Fe-oxidizing bacteria during diagenesis of sedimentary deposits, i.e. banded iron formations

沉积矿床成岩过程中铁氧化细菌细菌微化石的保存，即

基本信息

批准号：
188114433
负责人：
Professor Dr. Andreas Kappler
金额：
--
依托单位：
Arbeitsgruppe Geomikrobiologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/188114433?language=en
关键词：
Preservation bacterial microfossils Fe oxidizing

项目摘要

Precambrian sedimentary deposits such as banded iron formations (BIFs) are in the focus of researchers who aim to understand early life and its relevance for the evolution of the earth’s atmosphere. Iron-oxidizing bacteria are believed to be involved in the formation of Precambrian BIFs. The main goal of this project is to study on the laboratory scale diagenesis processes of cell-mineral aggregates and in particular to identify and quantitatively map structural and (organo-) chemical features on the micron- / submicronscale which are indicative of bacterial life. To this end experiments are planned with cellmineral aggregates of several model strains of laboratory cultures of Fe-oxidizing bacteria. Cell-mineral aggregates will be exposed to systematically increasing temperatures and pressures up to the conditions typically experienced by Precambrian BIFs. An appropriate set of correlative analytical microscopies will be determined. Samples will be prepared by conventional ultramicrotomy and focused-ion beam (FIB) milling for qualitative and quantitative analytical electron and soft X-ray spectromicroscopy studies to investigate both morphology and (organo-) chemical fingerprints of the bacterial residues. Additionally the 3D structure of the residues will be mapped by FIB-tomography. Infrared Spectromicroscopy and confocal Raman microscopy will provide further chemical information at moderate spatial resolution. The results from three different types of biogenic Fe-minerals (from encrusting, non-encrusting and stalk/sheath-forming bacteria) will be compared with regard to their potential for the preservation of bacterial microfossils.

带状铁地层（BIF）等前寒武纪沉积物是研究人员关注的焦点，他们旨在了解早期生命及其与地球大气演化的相关性。铁氧化细菌被认为参与了前寒武纪 BIF 的形成。该项目的主要目标是研究细胞矿物聚集体的实验室规模成岩过程，特别是识别和定量绘制微米/亚微米尺度上指示细菌生命的结构和（有机）化学特征。为此，计划使用铁氧化细菌实验室培养物的几种模型菌株的细胞矿物质聚集体进行实验。细胞矿物聚集体将暴露在系统升高的温度和压力下，直至达到前寒武纪 BIF 所经历的典型条件。将确定一组合适的相关分析显微镜。样品将通过传统的超薄切片和聚焦离子束 (FIB) 铣削制备，用于定性和定量分析电子和软 X 射线光谱显微镜研究，以研究细菌残留物的形态和（有机）化学指纹。此外，残基的 3D 结构将通过 FIB 断层扫描进行绘制。红外光谱显微镜和共焦拉曼显微镜将以中等空间分辨率提供进一步的化学信息。将比较三种不同类型的生物铁矿物（来自结壳、非结壳和茎/鞘形成细菌）的结果，以了解它们保存细菌微化石的潜力。