Photoferrotrophy, deposition of banded iron formations, and methane production in Archean oceans
Thompson, Katharine J. (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)
Kenward, Paul A. (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)
Bauer, Kohen W. (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)
Warchola, Tyler (University of Alberta. Department of Earth and Atmospheric Sciences)
Gauger, Tina (University of Tuebingen. Center for Applied Geosciences)
Martinez, Raul (Albert-Ludwigs-Universität. Institut für Geo- und Umweltnaturwissenschaften)
Simister, Rachel (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)
Michiels, Céline (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)
Llirós, Marc (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
Reinhard, Christopher T. (Georgia Institute of Technology. School of Earth and Atmospheric Sciences)
Kappler, Andreas (Center for Applied Geosciences. University of Tuebingen)
Konhauser, Kurt O. (Depart-ment of Earth and Atmospheric Sciences. University of Alberta)
Crowe, Sean (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)

Date:	2019
Abstract:	Banded iron formation (BIF) deposition was the likely result of oxidation of ferrous iron in seawater by either oxygenic photosynthesis or iron-dependent anoxygenic photosynthesis-photoferrotrophy. BIF deposition, however, remains enigmatic because the photosynthetic biomass produced during iron oxidation is conspicuously absent from BIFs. We have addressed this enigma through experiments with photosynthetic bacteria and modeling of biogeochemical cycling in the Archean oceans. Our experiments reveal that, in the presence of silica, photoferrotroph cell surfaces repel iron (oxyhydr)oxides. In silica-rich Precambrian seawater, this repulsion would separate biomass from ferric iron and would lead to large-scale deposition of BIFs lean in organic matter. Excess biomass not deposited with BIF would have deposited in coastal sediments, formed organic-rich shales, and fueled microbial methanogenesis. As a result, the deposition of BIFs by photoferrotrophs would have contributed fluxes of methane to the atmosphere and thus helped to stabilize Earth's climate under a dim early Sun.
Grants:	European Commission 307320
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Anoxygenic photosynthesis ; Banded iron formations ; Biogeochemical cycling ; Coastal sediments ; Methane production ; Organic-rich shales ; Oxygenic photosynthesis ; Photosynthetic bacterias
Published in:	Science advances, Vol. 5, Issue 11 (November 2019) , art. eaav2869, ISSN 2375-2548

DOI: 10.1126/sciadv.aav2869
PMID: 31807693

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