ORIGINAL RESEARCH article
Front. Mar. Sci.
Sec. Marine Biogeochemistry
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1627553
This article is part of the Research TopicQuantitative Reconstruction of Marine Carbonate Production: From Modern to Deep-Time OceansView all 11 articles
Calcified cyanobacteria from the Upper Ediacaran of South China
Provisionally accepted
- 1Chengdu University of Technology, Chengdu, China
- 2University of Cincinnati, Cincinnati, United States
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Fossil records of calcified cyanobacteria from the Neoproterozoic are rare despite the high carbonate saturation of contemporaneous seawater. In this study, tube-like microfossils in microbialites of the Upper Ediacaran Dengying Formation in South China are identified as the calcified cyanobacteria Girvanella. This discovery fills a gap in the fossil record of microbialite-hosted calcified cyanobacteria spanning the interval from the Cryogenian glaciations to the onset of the Cambrian Period. Petrographic and mineralogical analyses indicate that primary high-Mg calcite, precipitated in vivo within Girvanella sheaths as a likely precursor to microcrystalline dolomite, contributed to the exceptional preservation of these fossils. The sporadic occurrence of calcified cyanobacteria may reflect transient episodes of elevated carbonate saturation driven by fluctuations in seawater chemistry.Concurrently, the possible rapid evolution of CO2-concentration mechanisms (CCMs) may have enhanced the calcification capability of cyanobacteria. Thus, these features foreshadowed the widespread microbial calcification that emerged in the Cambrian.
Keywords: Denying Formation, Girvanella, Extracellular polymeric substances, Dolomite, Neoproterozoic, calcification
Received: 13 May 2025; Accepted: 04 Aug 2025.
Copyright: © 2025 Yijiang, Liu, Dong and Algeo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Zhong Yijiang, Chengdu University of Technology, Chengdu, China
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