Investigation of metal cycling in anoxic marine sediments by the application of stable isotopes

应用稳定同位素研究缺氧海洋沉积物中的金属循环

• 批准号: 148788878
• 负责人: Professorin Dr. Natascha Riedinger
• 金额: --
• 依托单位: Department of Earth Sciences
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/148788878?language=en
• 关键词: Investigation; metal; cycling; anoxic; marine

The goal of the proposed research is to better understand the cycling of iron and manganese in anoxic marine sediments and their relevance in the biogeochemical processing of carbon and sulfur. The main purpose is to explore iron and manganese pathways known under laboratory conditions but little studied in natural marine systems. Stable isotope measurements of molybdenum and iron will be emphasized. A specific objective is to study the reduction of reactive iron phases in the presence of methane-producing microorganisms, and the alteration of reactive manganese in these environments. Because manganese is mono-isotopic, processes leading to its alteration will be investigated by the application of molybdenum isotope techniques. The strong affinity between molybdenum and manganese oxides and associated fractionations are well known. Metal pathways are intimately tied to the cycling of carbon and sulfur. These relationships will also be investigated, inter alia, by the determination of sulfur isotopes on metal sulfides. Carbonate-associated sulfate and its stable isotopes will be analyzed as an integrated measure of the corresponding evolution of the sulfate reservoir during bacterial sulfate reduction. The proposed studies will be carried out on sediments from the Argentine Basin, which due to its dynamic sedimentary conditions, favors the occurrence of reactive metal oxides within methane-bearing sediments. As such, the possibility of anaerobic oxidation of methane tied syntrophically to concomitant reduction of iron, manganese and other oxide-bound metals is very real. To date, this pathway is underexplored, in part due to the limited number of easy accessible marine settings where reactive iron and manganese and abundant methane are juxtaposed in the limited presence or absence of sulfate. The sediments of the Argentine Basin are almost unique in this regard. Additionally, to investigate the importance of these pathways for the deep biosphere, we will compare the results with data of deep subsurface sediments from the Nankai Trough, Japan.

拟议研究的目标是更好地了解缺氧海洋沉积物中铁和锰的循环及其在碳和硫的生物地球化学过程中的相关性。主要目的是探索在实验室条件下已知但在自然海洋系统中很少研究的铁和锰途径。重点介绍钼和铁的稳定同位素测量。一个具体的目标是研究在产生甲烷的微生物存在下活性铁相的还原，以及在这些环境中活性锰的变化。由于锰是单同位素的，因此将应用钼同位素技术来研究导致其变化的过程。众所周知，钼和锰氧化物及其相关的分馏之间具有很强的亲和力。金属通道与碳和硫的循环密切相关。除其他外，还将通过测定金属硫化物上的硫同位素来研究这些关系。碳酸盐伴生硫酸盐及其稳定同位素的分析将作为细菌硫酸盐还原过程中硫酸盐储集层相应演化的综合手段。拟议的研究将在阿根廷盆地的沉积物中进行，由于其动态的沉积条件，有利于在含甲烷的沉积物中出现活性金属氧化物。因此，甲烷的厌氧氧化与铁、锰和其他氧化物结合的金属的伴随还原是非常真实的。到目前为止，对这一途径的探索不足，部分原因是由于在硫酸盐存在或不存在的情况下，活性铁、锰和丰富的甲烷并存的易于进入的海洋环境的数量有限。在这方面，阿根廷盆地的沉积物几乎是独一无二的。此外，为了研究这些路径对深层生物圈的重要性，我们将把结果与来自日本南开海槽的深层地下沉积物数据进行比较。