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

Laurence Yeung博士获得美国国家科学基金会地球科学博士后奖学金，在加州大学洛杉矶分校开展研究和教育项目。他将开发技术来研究极其罕见的18O2同位素在大气中的分布，这可以为冰川冰盖、陆地降水和生物圈生产力提供新的限制。为了完成这项任务，将进行实验室和建模研究，研究在光合作用、呼吸作用和平流层光化学等重要过程中，O2中已建立的同位素示踪剂（即18O/16O和17O/16O比率）与新的18O2示踪剂之间的协方差。另外的玻璃容器实验将模拟稳定状态下的大气-生物圈系统。然后将根据这些实验的结果解释当前的大气O2同位素收支，并将根据现代生物圈生产力和呼吸作用的其他测量方法对结果进行验证。该项目为了解大气、水圈和生物圈在过去气候变化中如何共同进化奠定了基础；只有有了这种认识，才能把人类对全球生物圈的影响置于适当的历史背景中。此外，有待开发的技术将进一步对大气和海洋科学等领域产生影响，以帮助它们更好地限制生物和非生物氧源和氧汇的分布、机制和全球重要性。杨将在洛杉矶当地的高中开展环境科学课程，指导本科生和研究生，并在国际地理生物学课程上为研究生和博士后学者讲课，这是他针对广泛潜在学生的综合教育计划的一部分。

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.