1. Departments of Microbiology and Immunology and Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
2. Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada.
3. Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany.
4. Institut für Geo- und Umweltnaturwissenschaften, Albert-Ludwigs-Universität, Mineralogie-Geochemie, 79104 Freiburg, Germany.
5. Department of Genetics and Microbiology, BioSciences Faculty, Universitat Autònoma de Barcelona, Catalunya, Spain.
6. School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA.