1. Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
2. Lamont Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA
3. Department of Geosciences, Stony Brook University, Stony Brook, NY 11794, USA
4. National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11793, USA
5. Department of Environmental Science, Barnard College, 404 Altschul Hall, New York, NY 10027, USA
6. Department of Geosciences, Science Center, Wellesley College, 106 Central Street, Wellesley, MA 02482, USA
7. The Earth Institute, Columbia University, New York, NY 10027, USA