1. Department of Microbiology; Oregon State University; 454 Nash Hall Corvallis OR 97331 USA
2. College of Earth, Ocean, and Atmospheric Sciences; Oregon State University; 454 Nash Hall Corvallis OR 97331 USA
3. Department of Ecology and Evolutionary Biology; Rice University; 6100 Main Street Houston TX 77005 USA
4. Division of Geological and Planetary Sciences; California Institute of Technology; 1200 E. California Blvd. Pasadena CA 91125 USA