1. Department of Environment and Sustainability, J. Craig Venter Institute , La Jolla , CA 92037 , USA
2. Department of Genomic Medicine and Infectious Diseases, J. Craig Venter Institute , La Jolla , CA 92037 , USA
3. School of Food and Agriculture, University of Maine , Orono , ME 04469 , USA
4. Maine Center for Genetics in the Environment, University of Maine , Orono, ME 04469 , USA
5. Microbiology Department, University of Tennessee , Knoxville , TN 37917 , USA