Group, University of California, Berkeley, California 94720, USA. 4Max Planck Research Group for Marine Geochemistry, University of Oldenburg, Institute for Chemistry and Biology of the Marine
Environment, 26129 Oldenburg, Germany. 5Max Planck Research Group for Marine Geochemistry, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany. 6Institute of Soil Science, Leibniz
Universita¨ t Hannover, 30419 Hannover, Germany. 7Department of Biology, University of Antwerp, 2610 Wilrijk, Belgium. 8Department of Crop and Soil Science, Oregon State University, Corvallis, Oregon
97331, USA. 9Lehrstuhl fu¨ r Bodenkunde, Technische Universita¨t Mu¨ nchen, 85354 Freising, Germany. 10Department of Crop and Soil Sciences, Cornell Center for a Sustainable Future, Cornell University,
Ithaca, New York 14853, USA. 11School of Civil Engineering and Geosciences, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle NE1 7RU, UK. 12Department of
Plant, Soil and Environmental Sciences, University of Firenze, 50144 Firenze, Italy. 13Norwegian Institute for Agricultural and Environmental Research, 1432A˚ s, Norway. 14Structural Biology, Weizmann
Institute, 76100 Rehovot, Israel. 15Max Planck Institute for Biogeochemistry, 07745 Jena, Germany.