1. Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
2. Globe Institute, Section for Geobiology, Copenhagen University, Øster Voldgade 5-7, 1350 Copenhagen K, Denmark
3. Technical University of Denmark, The Danish Hydrocarbon Research and Technology Centre, Elektrovej, 2800 Kongens Lyngby, Denmark