Biogenic Sources of Oxygenated Hydrocarbons in the Troposphere

94180730 Fall利用早期拨款进行的研究发现了甲醇和其他挥发性有机化合物（VOCs）从植被到大气的主要通量。现在建议使用灵敏和特异的酶/荧光方法来测量主要森林树种和作物中甲醇和其他含一碳的含氧碳氢化合物的排放，并确定叶细菌作为这些化合物的汇的作用。获得的数据将用于制定排放算法，这些算法将在实地实验中得到验证，将来可能用作美国生物源c1 - oxhc排放清单的基础。在区域和全球范围内，植物C1-oxHC向大气的通量可能非常大，具有甲醇的长距离输送和对大气化学的各种影响。目前，这些通量估计存在很大的不确定性。该项目将有助于更全面地了解甲醇、甲醛和甲酸在生物圈和大气之间的生物地球化学循环，并有助于建立这些C1化合物的自然来源和汇的知识。提出的工作的具体目标是：(1)完善分析植物中甲醇、甲醛和甲酸排放的酶和荧光方法；(2)明确植物C1-oxHC排放的“驱动因素”，收集实验室和温室实验中大型oxHC通量数据集；(3)开发生物源c1 - oxhc的排放算法；(4)确定叶片细菌作为大气C1-oxHCs的来源和/或汇的作用；(5)并通过适当的C1-oxHC通量现场测量来验证实验室排放算法。

94180730 Fall Research conducted with earlier grants has resulted in the discovery of major fluxes of methanol and other volatile organic compounds (VOCs) from vegetation to the atmosphere. It is now proposed to use sensitive and specific enzyme/fluorescence methods to measure the emission of methanol and other oxygenated hydrocarbons containing one carbon from major forest tree species and crops, and establish the role of leaf bacteria as sinks for these compounds. The data obtained will be used to develop emission algorithms that will be validated in field experiments and in the future might be used as the basis of a US emissions inventory of biogenic C1-oxHCs. Plant C1-oxHC fluxes to the atmosphere may be very large, both regionally and globally, with long range transport of methanol and a variety of impacts on atmospheric chemistry. Currently there are large uncertainties in these flux estimates. This project will contribute to a more complete picture of the biogeochemical cycling of methanol, formaldehyde, and formic acid between the biosphere and atmosphere, and help establish knowledge of natural sources and sinks of these C1 compounds. The specific goals of the proposed work are: (1) to perfect enzymatic and fluorescence methods for analyzing methanol, formaldehyde, and formic acid emissions from vegetation; (2) to define the "drivers" of plant C1-oxHC emissions and collect a large data set of oxHC fluxes in laboratory and greenhouse experiments; (3) develop emission algorithms for biogenic C1-oxHCs; (4) to establish the role of leaf bacteria as sources and/or sinks of atmospheric C1-oxHCs; (5) and to validate laboratory emissions algorithms by appropriate field measurements of C1-oxHC fluxes.