HR: 1340h
AN: B53C-1013    [Abstracts]
TI: Bacterial control on the structure of As-Fe oxy-hydroxides in acid mine drainage.
AU: * MORIN, G
EM: Guillaume.Morin@lmcp.jussieu.fr
AF: Laboratoire de Min‚ralogie Cristallographie de Paris, LMCP UMR7590 CNRS UPMC P7 IPGP 140 rue de Lourmel, Paris, 75015 France
AU: LEBRUN, S
EM: lebrun@lmcp.jussieu.fr
AF: Laboratoire de Min‚ralogie Cristallographie de Paris, LMCP UMR7590 CNRS UPMC P7 IPGP 140 rue de Lourmel, Paris, 75015 France
AU: JUILLOT, F
EM: juillot@lmcp.jussieu.fr
AF: Laboratoire de Min‚ralogie Cristallographie de Paris, LMCP UMR7590 CNRS UPMC P7 IPGP 140 rue de Lourmel, Paris, 75015 France
AU: CASIOT, C
EM: Corinne.Casiot@msem.univ-montp2.fr
AF: Laboratoire Hydrosciences, UMR 5569 CNRS IRD Universit‚ de Montpellier II, Montpellier, 34095 France
AU: BRUNEEL, O
EM: Odile.Bruneel@msem.univ-montp2.fr
AF: Laboratoire Hydrosciences, UMR 5569 CNRS IRD Universit‚ de Montpellier II, Montpellier, 34095 France
AU: BELIN, S
EM: belin@lure.u-psud.fr
AF: Synchrotron SOLEIL, L'Orme les Merisiers Saint-Aubin BP 48, Gif-sur-Yvette, 91192 France
AU: PROUX, O
EM: proux@esrf.fr
AF: ESRF, BP 220, Grenoble, 38043 France
AU: BROWN, G E
EM: gordon@pangea.stanford.edu
AF: Department of Geological and Environmental Sciences, Stanford University, Stanford, 94305-2115 United States
AU: GUYOT, F
EM: guyot@lmcp.jussieu.fr
AF: Laboratoire de Min‚ralogie Cristallographie de Paris, LMCP UMR7590 CNRS UPMC P7 IPGP 140 rue de Lourmel, Paris, 75015 France
AU: CALAS, G
EM: calas@lmcp.jussieu.fr
AF: Laboratoire de Min‚ralogie Cristallographie de Paris, LMCP UMR7590 CNRS UPMC P7 IPGP 140 rue de Lourmel, Paris, 75015 France
AB: Nano-crystalline or amorphous iron oxy-hydroxides are kinetically favored with respect to stable crystalline phases in low temperature environments. Therefore, they frequently occur as transient phases in Earth's surface environments. They exhibit very-high surface areas (few 100 cm2/g) and thus play a key role in the geochemical cycles of minor and trace elements, including toxic elements as arsenic. Natural low-temperature iron oxides also potentially host biological signatures since they can form through various biologically driven reactions. In the present communication, we compare the mineralogy and crystal chemistry of biogenic As-rich iron precipitates synthesized using various acidophilic bacterial strain isolated from an exceptionally arsenic-rich acid mine drainage [1]. XAS, XRD, SEM and TEM investigation of these highly reactive nano-minerals obtained in controlled conditions allows to better constrain their mechanisms of formation. Our data show that the enzymatic oxidation of Fe(II) and/or As(III) play a key role in controlling the nature of the mineral species precipitating in acid mine drainage. We show that the nature of mineral species forming from solutions can be directly determined by the metabolic activity of specific bacterial strains. This influence is thought to be primarily indirect, bacteria controlling the rate of Fe(II) and As(III) oxidation reactions, which in turn leads to various Fe(III) and As(V) super-saturation conditions. These latter parameters are crucial in controlling the structure of nano-crystalline As-Fe low temperature minerals. 1- Morin et al. (2003) Bacterial formation of tooeleite and mixed As(III)/(V)-Fe(III) gels in the CarnoulŠs acid mine drainage, France. A XANES, XRD and SEM study. Environ. Sci. and Technol. 37,1705-1712.
DE: 3620 Crystal chemistry
DE: 1871 Surface water quality
DE: 1045 Low-temperature geochemistry
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 1000 GEOCHEMISTRY (New field, replaces Rock Chemistry)
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting