1. Institut de Minéralogie et de Physique des Milieux Condensés, UMR 7590, CNRS, Universités Paris 6 et Paris 7, Paris, and IMPMC, 140 Rue de Lourmel, Paris, France
2. BIMR, McMaster University, Hamilton, and Canadian Light Source, 101 Perimeter Road, Saskatoon, Saskatchewan, Canada
3. Geomicrobiology, Center for Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen, Germany