Iron-rich microband formation in marine sediments by hydrothermal iron cycling bacteria at Lucky Strike

Aubineau, Jeremie, Chi Fru, Ernest ORCID: https://orcid.org/0000-0003-2673-0565, Destrigneville, Christine, Decrausaz, Thierry, Parat, Fleurice, Baron, Fabien, Nederbragt, Alexandra, Henry, Manuel, Castillo, Alain, Rommevaux, Celine and Chavagnac, Valerie 2025. Iron-rich microband formation in marine sediments by hydrothermal iron cycling bacteria at Lucky Strike. Communications Earth & Environment 6 , 338. 10.1038/s43247-025-02223-2

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Abstract

Models describing banded iron formation deposition beneath oxygenated Paleoproterozoic marine shelf waters assume that microaerophilic iron-oxidizing microorganisms were significant contributors. However, direct evidence for this mechanism is lacking, and it remains unclear how associated primary organic biomass and biogenic iron oxyhydroxides transformed into organic carbon-poor iron oxide/carbonate-rich bands in banded iron formations. Here we explore in situ modern Zetaproteobacterial iron-oxidizing mats thriving in the Lucky Strike hydrothermal vent field to develop an empirical model that explains the potential contribution of iron-based metabolisms to deposition of rocks resembling banded iron formations. Petrographic, mineralogical, and geochemical data suggest that abundant production of Zetaproteobacterial stalks nucleates and drives spontaneous biotic/abiotic ferrihydrite precipitation in the mats. Subsequent early diagenetic anaerobic microbial oxidation of dead biomass as the mats aged, coupled to microbial reduction of iron oxyhydroxides/oxides, generates ferrous carbonates and mixed valence magnetite. Collectively, this forms crystalline iron-rich organic carbon-lean 13C-depleted layers reminiscent of Precambrian banded iron formation microbands.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Schools > Earth and Environmental Sciences
Publisher:	Nature Research
ISSN:	2662-4435
Date of First Compliant Deposit:	7 April 2025
Date of Acceptance:	18 March 2025
Last Modified:	07 May 2025 10:46
URI:	https://orca.cardiff.ac.uk/id/eprint/177440

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