Collaborative Research: Experimental and Modeling Study of Ecosystem-Atmosphere Oxygen Isotopic Fluxes and Discrimination Mechanisms

合作研究：生态系统-大气氧同位素通量及判别机制的实验与模拟研究本项目的目标是研究控制陆地植被与大气之间CO2和H2O中氧同位素（18 O和16 O）交换的过程。大豆和玉米将用作C3和C4植物的模型系统。可调谐二极管激光吸收光谱将与微气象学方法相结合，以提供同步，近连续的测量同位素混合比和二氧化碳和水蒸气的同位素通量，以及18 O的歧视因素在生态系统的规模。 确定生态系统尺度的18 O歧视的能力是至关重要的一些基础科学问题，有关大气碳收支和生态系统过程。拟议活动的更广泛影响包括获取独特的数据集，用于验证大气碳收支模型。创新的研究方法将提高全球碳和能量通量观测网络的能力，并促进大学科学家和私营企业工程师之间的合作。在项目期间获得的新知识将通过一次特别会议和对本科生和研究生的培训转移到更大的科学界。最后，通过18 O同位素的CO2和水的耦合交换的总体战略应该打开一个新的层面，以真正综合的方式调查碳和水循环。

Collaborative Research: Experimental and Modeling Study of Ecosystem-Atmosphere Oxygen Isotopic Fluxes and Discrimination MechanismsThe goal of this project is to investigate processes that control the exchange of oxygen isotopes (18O and 16O) in CO2 and H2O between terrestrial vegetation and the atmosphere. Soybean and corn will be used as model systems for C3 and C4 plants. Tunable diode laser absorption spectroscopy will be combined with the micrometeorological methods to provide simultaneous, near-continuous measurement of isotopomer mixing ratios and isotopic fluxes of CO2 and water vapor, and 18O discrimination factors at the ecosystem scale. The ability to determine the ecosystem-scale 18O discrimination is essential to a number of fundamental science questions relevant to atmospheric carbon budget and ecosystem processes. The broader impacts of the proposed activity include the acquisition of unique datasets for validation of atmospheric carbon budget models. The innovative research methods will enhance the capacity of the global carbon and energy flux observational network and foster collaboration between university scientists and engineers in a private industry. The new knowledge gained during the project will be transferred to the greater scientific community through a special conference session and training of undergraduate and graduate students. Finally, the overall strategy on the coupled exchanges of CO2 and water through the 18O isotopes should open a new dimension for investigating the carbon and water cycles in a truly integrated manner.