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DOI : 10.1016/j.scitotenv.2011.03.030

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Science of the Total Environment 409 (2011) 2586-2596 409 (2011) 2586-2596

The formation of green rust induced by tropical river biofilm components

Frederic Jorand 1, Asfaw Zegeye 1, Jaafar Ghanbaja 2, Mustapha Abdelmoula 1

(03/05/2011)

In the Sinnamary Estuary (French Guiana), a dense red biofilm 15 grows on flooded surfaces. In order to characterize the iron oxides in this biofilm and to establish the nature of secondary minerals formed after anaerobic incubation, we conducted solid analysis and performed batch incubations. Elemental analysis indicated a major amount of iron as inorganic compartment along with organic matter. Solid analysis showed the presence of two ferric oxides ferrihydrite and lepidocrocite. Bacteria were abundant and represented more than 1011 cells g-1 of dry weight among which iron reducers were revealed. Optical and electronic microscopy analysis revealed than the bacteria were in close vicinity of the iron oxides. After anaerobic incubations with exogenous electron donors, the biofilm's ferric material was reduced into green rust, a FeII-FeIII 25 layered double hydroxide. This green rust remained stable for several years. From this study and previous reports, we suggest that ferruginous biofilms should be considered as a favorable location for GR biomineralization when redox conditions and electron donors availability are gathered.

1 :	Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME)
	CNRS : UMR7564 – Université Henri Poincaré - Nancy I
2 :	Institut Jean Lamour : Matériaux -Métallurgie - Nanosciences - Plasma - Surfaces (IJL)
	Université Henri Poincaré - Nancy I – CNRS : UMR7198 – Institut National Polytechnique de Lorraine (INPL) – Université Paul Verlaine - Metz

Domaine

:

Physique/Physique/Chimie-Physique

Mots Clés : green rust – biofilm – iron oxide – lepidocrocite – ferrihydrite – biomineralization – solid analysis – secondary iron minerals

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Contributeur : Mustapha Abdelmoula <>

Soumis le : Vendredi 27 Juillet 2012, 18:07:37

Dernière modification le : Vendredi 27 Juillet 2012, 18:15:00