title: Chemical signature of magnetotactic bacteria.
abstract: There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record.
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, 75238 Paris, France; Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7590 CNRS, Institut de Recherche pour le Développement UMR 206, Museum National d'Histoire Naturelle, 75252 Paris Cedex 05, France; and amor@ipgp.fr.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Amor
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, 75238 Paris, France;
authors.forename: Vincent
authors.initials: V
authors.lastname: Busigny
authors.affiliation: Nanobactérie SARL, 75016 Paris, France.
authors.forename: Mickaël
authors.initials: M
authors.lastname: Durand-Dubief
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, 75238 Paris, France;
authors.forename: Mickaël
authors.initials: M
authors.lastname: Tharaud
authors.affiliation: Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7590 CNRS, Institut de Recherche pour le Développement UMR 206, Museum National d'Histoire Naturelle, 75252 Paris Cedex 05, France; and.
authors.forename: Georges
authors.initials: G
authors.lastname: Ona-Nguema
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, 75238 Paris, France;
authors.forename: Alexandre
authors.initials: A
authors.lastname: Gélabert
authors.affiliation: Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7590 CNRS, Institut de Recherche pour le Développement UMR 206, Museum National d'Histoire Naturelle, 75252 Paris Cedex 05, France; and Nanobactérie SARL, 75016 Paris, France.
authors.forename: Edouard
authors.initials: E
authors.lastname: Alphandéry
authors.affiliation: Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7590 CNRS, Institut de Recherche pour le Développement UMR 206, Museum National d'Histoire Naturelle, 75252 Paris Cedex 05, France; and.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Menguy
authors.affiliation: Institut de Physique du Globe de Paris, Sorbonne Paris Cité, Université Paris Diderot, UMR 7154 CNRS, 75238 Paris, France;
authors.forename: Marc F
authors.initials: MF
authors.lastname: Benedetti
authors.affiliation: Nanobactérie SARL, 75016 Paris, France.
authors.forename: Imène
authors.initials: I
authors.lastname: Chebbi
authors.affiliation: Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Universités, Université Pierre et Marie Curie, UMR 7590 CNRS, Institut de Recherche pour le Développement UMR 206, Museum National d'Histoire Naturelle, 75252 Paris Cedex 05, France; and.
authors.forename: François
authors.initials: F
authors.lastname: Guyot
mesh_terms: D000704:Analysis of Variance; D015415:Biomarkers / Q000032:analysis* / Q000378:metabolism; D018929:Cell Culture Techniques; D005285:Fermentation; D052203:Ferrosoferric Oxide / Q000138:chemical synthesis; D058185:Magnetite Nanoparticles / Q000032:analysis*; D042201:Magnetospirillum / Q000737:chemistry* / Q000254:growth & development* / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D014131:Trace Elements / Q000032:analysis* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D058185:Magnetite Nanoparticles; D014131:Trace Elements; D052203:Ferrosoferric Oxide
keywords: biomineralization; magnetite; magnetotactic bacteria; trace element incorporation