Characterization of iron oxide concretions associated with bacterial symbionts of a deep-sea hydrothermal vent shrimp. An investigation by various techniques in electron microscopy

Laure Corbari (1a), Magali Zbinden (2), Marie-Anne Cambon-Bonavita (3), Frédéric Boulvain (1b), Françoise Gaill (2) and Philippe Compère (a1)
(1) Université de Liège,
    (a) Dept. Sciences et Gestion de l'Environnement et Cellule d'Appui Technologique en Microscopie (CATµ),
    (b) Dept. Géologie , Sart-Tilman, B-4000 Liège, Belgium
(2) UMR CNRS 7138, Systématique, Adaptation et Evolution, Université Pierre et Marie Curie, 7 Quai St Bernard, Bâtiment A, 75252 Paris Cedex 05, France
(3) UMR 6197, Laboratoire de Microbiologie des Environnements Extrême, Ifremer, centre de Brest, BP 70, 29280 Plouzané, France
   

The shrimps, Rimicaris exoculata live in dense swarms (> 2,500 ind./m2) on black smoker chimneys of Mid-Atlantic Ridge (MAR) hydrothermal vent sites. They depend on chemoautotrophic bacteria harboured in their gill chamber and fuelled by vent fluid reducing compounds (HS-, Fe2+, CH4). Iron oxide nucleates on the bacteria and progressively develops in a heavy mineral crust.

The concretions were imaged down to nanometre scale by use of several techniques of electron microscopy available in the Centre for Applied Technology in Microscopy (Catµ) of the University of Liege (SE-, BSE-, ESED-, GSED-imaging in a FEI XL30 ESEM-FEG, BF/HAADF-imaging and SAD in a Tecnai G2 Twin STEM, EDAX in SEM and TEM).

L. Corbari was post-doctoral fellow research-assistant of the FNRS (Belgium). The work was partly funded with the help of the European MOMARNET program and of the Belgian Fund for Joint Basic Research (F.R.F.C-Belgium, convention n° 2.4594.07.F)