1. Department of Biology, Microbiology section, Aarhus University, Aarhus C, Denmark.
2. Department of Geoscience, Aarhus University, Aarhus C, Denmark.
3. Department of Chemistry, Aarhus University, Aarhus C, Denmark.
4. Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Aarhus C, Denmark.