1. Biosphere 2 Center of Columbia University; Oracle Arizona USA
2. Lamont-Doherty Earth Observatory of Columbia University; Palisades New York USA
3. Department of Earth Sciences; University of Southern California; Los Angeles California USA
4. Environmental Research Laboratory, Department of Soil, Water and Environmental Science; University of Arizona; Tucson Arizona USA
5. Ocean Chemistry Division; NOAA-AOML; Miami Florida USA
6. AMS 14C Laboratory; Institute of Particle Physics; Zurich Switzerland