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

劳伦斯·杨博士被授予美国国家科学基金会地球科学博士后奖学金，以发展加州大学洛杉矶分校的研究和教育项目。他将开发技术来研究大气中极其罕见的O2的18O2同位素的分布，这可能会随着时间的推移对冰川覆盖、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，将进行实验室和模拟研究，以研究在光合作用、呼吸作用和平流层光化学等重要过程中，氧气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。附加的水族箱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目前的大气O2同位素平衡，并将根据现代生物圈生产力和呼吸的其他衡量标准对结果进行验证。该项目为理解大气、水圈和生物圈如何在过去的气候变化中共同演化奠定了基础；只有在这种类型的理解下，才能将人类对全球生物圈的印记置于适当的历史背景中。此外，将开发的技术将进一步对大气和海洋科学等领域产生影响，帮助它们更好地限制生物和非生物源和氧汇的分布、机制和全球重要性。杨家诚将在洛杉矶当地的高中开展课堂环境科学项目，指导本科生和研究生，并在面向研究生和博士后学者的国际地球生物学课程上讲课，这是他的综合教育计划的一部分，该计划针对广泛的潜在学生。

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.