Interactions matière minérale-matière organique-microbe: impacts environnementaux de l'échelle moléculaire à l'échelle macroscopique

Translated title of the contribution: Mineral-organic-microbe interactions: Environmental impacts from molecular to macroscopic scales

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The role of microbes in geological processes is discussed with particular reference to the geochemical cycle involving iron. Microbial oxidation of Fe(II) minerals can occur via at least three mechanisms, the most important involving acidophilic prokaryotes which promote oxidation of iron sulphides. Accelerated breakdown of arsenopyrite is a good example, where multi-step electrochemical reactions are facilitated by the presence of organisms such as Leptospirillum ferrooxidans. Other organisms actively promote the reduction of Fe(III) to more soluble Fe(II). Reduction rates are highly variable, depending on mineral substrate, with oxyhydroxides being most reactive. Proper understanding of such redox processes requires knowledge of interactions at the molecular scale. Advances are being made through genetic studies of relevant organisms, and of mineral surfaces as exemplified by our experimental and computational studies of iron oxides such as magnetite, the reaction of which with simple organic molecules shows diverse behaviour. Mineral-organic interactions precede formation of bacterial biofilms, which can create local geochemical environments causing mineral precipitation. Biofilms and precipitate phases can have a major influence on fluid flow through fractures or porous media as we demonstrate using experiments from micro- to macro-scales.
    Translated title of the contributionMineral-organic-microbe interactions: Environmental impacts from molecular to macroscopic scales
    Original languageFrench
    Pages (from-to)140-159
    Number of pages19
    JournalAcadémie des Sciences. Comptes Rendus. Geoscience
    Volume343
    Issue number2-3
    DOIs
    Publication statusPublished - Feb 2011

    Keywords

    • Biofilms
    • Iron oxide surfaces
    • Microbial redox reactions

    Fingerprint

    Dive into the research topics of 'Mineral-organic-microbe interactions: Environmental impacts from molecular to macroscopic scales'. Together they form a unique fingerprint.

    Cite this