'Clumped' isotope geochemistry of 18-O2 for paleohydrology and paleobiology

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Dr. Laurence Yeung has been awarded a NSF Earth Sciences Postdoctoral Fellowship to develop a program of research and education at the University of California, Los Angeles. He will develop techniques to study the distribution of the exceedingly rare 18O2 isotopologue of O2 in the atmosphere, which can provide new constraints on glacial ice cover, terrestrial precipitation, and biosphere productivity over time. To accomplish this task, laboratory and modeling studies will be conducted to study the covariances between established isotopic tracers in O2 (i.e., 18O/16O and 17O/16O ratios) and the new 18O2 tracer during important processes: photosynthesis, respiration, and stratospheric photochemistry. Additional terrarium experiments will simulate the atmosphere-biosphere system at steady state. The current atmospheric O2 isotopologue budget will then be interpreted based on the results of these experiments, and the results will be validated against other measures of biosphere productivity and respiration in the modern era. This project lays the fundamental groundwork for understanding of how the atmosphere, hydrosphere, and biosphere co-evolved during past climatic changes; only with this type of understanding can the human imprint on the global biosphere be put into its proper historical context. In addition, the techniques to be developed will further have an impact on fields such as the atmospheric and ocean sciences to help them better constrain the distribution, mechanisms, and global importance of biological and abiological sources and sinks of oxygen.Dr. Yeung will conduct in-class environmental science programs at local Los Angeles high schools,mentor undergraduate and graduate students, and give lectures at the International GeoBiology course for graduate students and postdoctoral scholars as part of his integrated educational program, which is aimed at a wide range of potential students.