Research Starter Grant: Using Stable Isotopes to Identify the Components of Forest Canopy Evapotranspiration

植物叶片的同位素组成提供了有关植物单位生长过程中失水量的信息。此外，最近的数据表明，碳和氢同位素测量可以用来确定森林树冠上的水蒸气是来自土壤，通过蒸发，还是来自植物。在这项研究中，将研究树叶和冠层水汽的同位素组成，以了解和预测植被对潜在的降水变化的响应，并确定可能的植被对生态系统尺度水循环的反馈。该项目旨在测试与加州大学河滨分校(UCR)附近加州大学自然保护区系统的詹姆斯·圣哈辛托山脉保护区的植被-大气水循环相关的三个假说。这三个假设将植物生理学与生态系统水平的过程结合在一起，并将在了解植被对降水状况预测变化的响应的背景下进行评估。该项目将直接支持华东理工大学新的稳定同位素设施的开发，从而为最先进的科学基础设施做出贡献。它还将促进一位新的助理教授的专业发展，以及他与一群具有相似兴趣的本地科学家的互动。此外，詹姆斯保护区的工作将受益于该地点正在进行的密集研究，该地点已成为创新和实验技术的温床。这项调查的新颖性将使学生有机会向学生传授这项技术，并进一步使用它。

The isotopic composition of plant leaves provides information about the amount of water lost per unit of plant growth. Further, recent data show that carbon and hydrogen isotope measurements can be used to determine whether water vapor in the forest canopy came from the soil, via evaporation, or from plants. In this study, the isotopic composition of leaves and canopy water vapor will be investigated to understand and predict the responses of vegetation to potential changes in precipitation, and to identify possible vegetation feedbacks to ecosystem-scale water cycling. The project is designed to test three hypotheses relating vegetation-atmosphere water cycling at the James San Jacinto Mountain Reserve of the University of California Natural Reserve System, near University of California, Riverside (UCR). The three hypotheses integrate plant physiology to ecosystem-level processes, and will be evaluated in the context of understanding the responses of vegetation to predicted changes in precipitation regime. This project will support directly the development of new stable isotope facilities at UCR, and thus contribute to state-of-the-art scientific infrastructure. It also will promote the professional development of a new assistant professor, and his interaction with a pioneering group of local scientists with similar interests. Furthermore, work at the James Reserve will benefit, and benefit from, intensive on-going studies at that location, which has become a hotbed of innovative and experimental techniques. The novelty of this investigation will allow opportunities to teach this technique to students and further its use.