1. Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic
2. Centre for Astrobiology and Extremophiles Research, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK
3. Instituto de Recursos Naturales, CCMA, CSIC, c/Serrano 115, 28006 Madrid, Spain
4. Area Geodinamica Interna, Facultad de Humanidades y Educacion, Universidad de Burgos, c/Villadiego s/n, 09001 Burgos, Spain
5. SETI Institute—NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035, USA