* Corresponding authors

a Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
E-mail: noel@slac.stanford.edu

b Department of Geological Sciences, School of Earth, Energy & Environmental Sciences, Stanford University, Stanford, CA 94305-2115, USA

c Department of Environmental Geosciences, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Vienna, Austria

d Center for Environmental Implications of NanoTechnology (CEINT), Duke University, P.O. Box 90287, Durham, NC 27708-0287, USA

e Department of Earth System Science, Stanford University, Stanford, CA 94305, USA

f Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA