Devaki Bhaya1, Peter Lindblad2. 1. Carnegie Institution for Science, Stanford, CA, 94305, USA. dbhaya@carnegiescience.edu. 2. Microbial chemistry, Department Chemistry - Angstrom, Faculty of Science and Technology, Uppsala University, Box 523, 751 20, Uppsala, Sweden. Peter.Lindblad@kemi.uu.se.