1. Archaea Biology and Ecogenomics Division, University of Vienna, Vienna, Austria
2. Center for Environmental Biotechnology, University of Tennessee, Knoxville, Tennessee, USA
3. Department of Microbiology, Department of Civil and Environmental Engineering, and Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee, USA
4. Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA