干旱区生态环境知识资源中心(Arid): Methanogen-Mediated Precipitation of Mn Carbonates at the Expense of Mn Oxides

Arid

DOI	10.1029/2023GL106921
	Methanogen-Mediated Precipitation of Mn Carbonates at the Expense of Mn Oxides
	Cai, Shixi; Wei, Gangjian; Xian, Haiyang; Zhu, Jianxi; Xu, Yi-Gang
通讯作者	Wei, GJ ; Xu, YG
来源期刊	GEOPHYSICAL RESEARCH LETTERS
ISSN	0094-8276
EISSN	1944-8007
出版年	2024
卷号	51 期号:7
英文摘要	Whether Mn carbonates can be used as a proxy for the oxygenation event is debated. Here we examined the Early Cretaceous lacustrine Mn carbonates from North China, which contain abundant microbial fossils. The extremely positive delta 13C (up to +15 parts per thousand relative to Vienna Peedee belemnite) and micro-area enrichment of Ni strongly indicate a methanogenic archaea origin of these microorganisms. Transmission electron microscope and electron energy loss spectroscopy show the nanoscale transformation of Mn-oxides (Mg-exchanged phyllomanganate) to Mn carbonates (kutnohorite), on extracellular polymeric substances. The reaction of the Mn oxides with organic matter resulted in increasing pH and alkalinity, together with the fluctuating pH, offering a suitable micro-environment for the transformation processes. These Mn carbonates are therefore indicative of an oxidized, sulfate-absent environment. The depicted scenario serves as a reference to ocean of the early Earth and provides a referable Mn oxide tracer for determining the emergence of the Great Oxidation Event. Microbial-mineral interactions have played an important role in the evolution of the Earth. Active methanogenesis exists in submerged sediments, and the biological activity of methanogen is directly or indirectly involved in the process of geochemical cycling and mineral precipitation. In modern ocean environments, the methanogenesis zone and the manganese reduction zone are respectively, located in the lower and upper layers of a chemical zone, so it is difficult for them to interact directly with each other. This study documents evidence for the direct reaction between them in the Early Cretaceous lacustrine sediment cores from north China. Precipitation of Mn carbonates was likely mediated by methanogenesis in couple with Mn oxide reduction. Such an environment resembles the oxygen oases in the ocean before the Great Oxidation Event and thus provides new insights into the marine environment at that time. Abundant methanogen microfossils in Mn carbonates with positive delta 13C Nanoscale transformation from Mn oxides to Mn carbonates pH fluctuations due to changes in redox conditions promote the formation of kutnohorite
英文关键词	methanogen microfossils Mn-carbonates extracellular polymeric substances mineral-microbe interaction dolomite problem great oxidation event
类型	Article
语种	英语
开放获取类型	gold
收录类别	SCI-E
WOS记录号	WOS:001194851100001
WOS关键词	MICROBIAL DOLOMITE ; MANGANESE ; GEOCHEMISTRY ; TRANSITION ; NUCLEATION ; FOSSILS ; GROWTH
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/403953
推荐引用方式 GB/T 7714	Cai, Shixi,Wei, Gangjian,Xian, Haiyang,et al. Methanogen-Mediated Precipitation of Mn Carbonates at the Expense of Mn Oxides[J],2024,51(7).
APA	Cai, Shixi,Wei, Gangjian,Xian, Haiyang,Zhu, Jianxi,&Xu, Yi-Gang.(2024).Methanogen-Mediated Precipitation of Mn Carbonates at the Expense of Mn Oxides.GEOPHYSICAL RESEARCH LETTERS,51(7).
MLA	Cai, Shixi,et al."Methanogen-Mediated Precipitation of Mn Carbonates at the Expense of Mn Oxides".GEOPHYSICAL RESEARCH LETTERS 51.7(2024).