1. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
2. Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, United States
3. Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
4. Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States