Pelagic photoferrotrophy and iron cycling in a modern ferruginous basin
Llirós, Marc (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)
García-Armisen, Tamara (Université Libre de Bruxelles)
Darchambeau, François (University of Liège)
Morana, Cédric (Katholieke Universiteit Leuven. Department of Earth and Environmental Sciences)
Triadó-Margarit, Xavier (Universitat de Girona. Institut d'Ecologia Aquàtica)
Inceoğlu, Özgül (Université Libre de Bruxelles)
Borrego, Carles M. (Agència Catalana de l'Aigua. Departament de Control i Qualitat de les Aigües)
Bouillon, Steven (Katholieke Universiteit Leuven)
Servais, Pierre (Université Libre de Bruxelles)
Borges, Alberto V. (Université de Liège. Chemical Oceanography Unit)
Descy, Jean-Pierre (University of Namur. Research Unit in Environmental and Evolutionary Biology)
Canfield, Don E. (University of Southern Denmark. Institute of Biology)
Crowe, Sean (University of British Columbia. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences)

Data:	2015
Resum:	Iron-rich (ferruginous) ocean chemistry prevailed throughout most of Earth's early history. Before the evolution and proliferation of oxygenic photosynthesis, biological production in the ferruginous oceans was likely driven by photoferrotrophic bacteria that oxidize ferrous iron {Fe(II)} to harness energy from sunlight, and fix inorganic carbon into biomass. Photoferrotrophs may thus have fuelled Earth's early biosphere providing energy to drive microbial growth and evolution over billions of years. Yet, photoferrotrophic activity has remained largely elusive on the modern Earth, leaving models for early biological production untested and imperative ecological context for the evolution of life missing. Here, we show that an active community of pelagic photoferrotrophs comprises up to 30% of the total microbial community in illuminated ferruginous waters of Kabuno Bay (KB), East Africa (DR Congo). These photoferrotrophs produce oxidized iron {Fe(III)} and biomass, and support a diverse pelagic microbial community including heterotrophic Fe(III)-reducers, sulfate reducers, fermenters and methanogens. At modest light levels, rates of photoferrotrophy in KB exceed those predicted for early Earth primary production, and are sufficient to generate Earth's largest sedimentary iron ore deposits. Fe cycling, however, is efficient, and complex microbial community interactions likely regulate Fe(III) and organic matter export from the photic zone.
Ajuts:	European Commission 240002
Drets:	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, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	Scientific reports, Vol. 5 (September 2015) , art. 13803, ISSN 2045-2322

DOI: 10.1038/srep13803
PMID: 26348272

8 p, 1.2 MB

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