HR: 1330h
AN: B12C-0802    [PDF]
TI: Formation and Stabilization of Mixed Valence Ferrihydrite on Bacterial Surfaces From Hydrothermal Vents
AU: Gloter, A
EM: gloter@lps.u-psud.fr
AF: Laboratoire de Physique des Solides, Universite Paris Sud, Orsay, 91405 France
AU: Zbinden, M
EM: mzbinden@snv.jussieu.fr
AF: Adaptations aux milieux extremes, 7, quai Saint Bernard, Paris, 75005 France
AU: * Guyot, F
EM: guyot@lmcp.jussieu.fr
AF: LMCP-IPGP, 4 place Jussieu, Paris, 75005 France
AU: Gaill, F
EM: francoise.gaill@snv.jussieu.fr
AF: Adaptations aux milieux extremes, 7, quai Saint Bernard, Paris, 75005 France
AU: Colliex, C
EM: colliex@lps.u-psud.fr
AF: Laboratoire de Physique des Solides, Universite Paris Sud, Orsay, 91405 France
AB: The dynamics of iron oxidation and reduction at hydrothermal sites is an important biogeochemical process which involves major biomineralization of iron oxides. In this study, we have studied biomineralization by the Rimicaris exoculata shrimp collected at a Mid Atlantic Ridge hydrothermal vent. The structure, morphology and impurities distributions of the minerals were analyzed by Transmission electron microscopy and electron energy loss spectroscopy. The main minerals observed are clusters of two-lines ferrihydrite, found attached to the bacterial cells present in the organ scaphognatite of the shrimp. EELS measurements at the Fe 2p excitation demonstrate that the ferrihydrite is bearing a mixed valence iron distribution. The stability of this uncommon phase is then discussed based on work previously reported in literature for analogous poorly ordered iron oxides. The specific biomineralization mechanism might be a key to the stabilization of this phase.
DE: 1615 Biogeochemical processes (4805)
DE: 4803 Bacteria
DE: 4832 Hydrothermal systems
DE: 4851 Oxidation/reduction reactions
SC: Biogeosciences [B]
MN: 2003 Fall Meeting