Collaborative Research: Biogenic Volatile Organic Compounds and their Impacts in a Changing Temperate Forest

该项目是由来自四家机构的研究人员合作完成的，他们在测量和解释生物挥发性有机碳（BVOC）化合物和相关反应产物方面具有互补的专业知识。该项目被设想为一项长期研究计划的一部分，旨在测试以下假设：“BVOC排放对气候的影响取决于BVOC的结构；虽然异戊二烯会影响臭氧的产生，但萜烯在固氮和产生气溶胶方面更有效；森林中萜烯占主导地位的变化将导致更多的碳封存，其他因素保持不变。”在第一年，主要研究人员（pi）将在实验室中构建和测试一个自动化测量系统，该系统由采样设备，二维气相色谱仪（GCxGC）和校准系统组成，以每小时量化特定BVOCs和反应产物的环境混合比率。采样装置将浓缩BVOCs和反应产物，并转移到装有两个二级柱的气相色谱。一个通道将输入火焰电离检测器（FID）来量化BVOCs，另一个通道将输入电子捕获检测器（ECD）来量化氧化产物（包括硝酸盐和羟基硝酸盐）。通用工具校准源将包括一个包含多个化合物特定扩散管和相关管道的温控浴。在第二年，pi将在密歇根大学生物站（UMBS）的氧化剂：光化学、排放和运输研究项目（PROPHET）站点部署并持续运行这种新型半自主测量系统，为期4周。实地部署的目标是测试该仪器的性能，可靠地量化森林冠层内外环境空气中的一系列重烷烃、烯烃、芳烃、异戊二烯、montoterpenes、倍半萜烯、醛类和酮类、醇类和有机硝酸盐。BVOCs和反应产物半自主测量系统的开发将提高观测分辨率，用于研究森林动态、氧化过程、气溶胶产生、氮和碳固存以及相关的气候反馈之间的相互作用。该项目的成果还将扩展PROPHET数据档案，该档案一直是广泛调查森林-大气相互作用的宝贵社区资源。研究生和本科生将直接参与仪器的构建和现场测试。研究结果将通过科学文献的文章进行传播，并将其纳入基于探究的教学网络任务中，以帮助高中生了解全球气候变化背景下的生物圈-大气研究。这个webquest将成为UMBS类似教育资源图书馆的一部分。

This project is a collaborative effort involving investigators from four institutions with complimentary expertise in measuring and interpreting biogenic volatile organic carbon (BVOC) compounds and associated reaction products. The project is envisioned as part of a longer-term research initiative designed to test the following hypothesis: "The impact of BVOC emissions on climate depends on the structures of the BVOC; while isoprene can impact ozone production, terpenes are more effective at nitrogen sequestration and aerosol production; the change to terpene-dominance in forests will lead to more carbon sequestration, other factors remaining the same." During year 1, the principal investigators (PIs) will construct and test in the laboratory an automated measurement system consisting of a sampling apparatus, a two-dimensional gas chromatograph (GCxGC), and a calibration system to quantify ambient mixing ratios of speciated BVOCs and reaction products hourly. The sampling apparatus will concentrate BVOCs and reaction products and transfer to a GC fitted with two secondary columns. One channel will feed a flame ionization detector (FID) to quantify BVOCs and the other an electron capture detector (ECD) to quantify oxidation products (including nitrates and hydroxynitrate). The general utility calibration source will include a temperature-controlled bath containing multiple compound-specific diffusion tubes and associated plumbing. During year 2, the PIs will deploy and continuously operate this novel semi-autonomous measurement system at the Program for Research on Oxidants: PHotochemistry, Emissions, & Transport (PROPHET) site at the University of Michigan Biological Station (UMBS) over a 4-week period during the growing season. The goal of the field deployment will be to test the instrument's performance in reliably quantifying a broad suite of heavy alkanes, alkenes, aromatics, isoprene, montoterpenes, sesquiterpenes, aldehydes and ketones, and alcohols, and organic nitrates in ambient air within and above the forest canopy.The development of a semi-autonomous measurement system for BVOCs and reaction products will enhance observational resolution for investigations of interactions among forest dynamics, oxidation processes, aerosol production, nitrogen and carbon sequestration, and associated feedbacks on climate. Results from the project will also extend the PROPHET data archive, which has been a valuable community resource for broader investigations of forest-atmosphere interactions. Graduate and undergraduate students will participate directly in constructing and field testing the instrument. Results will be disseminated through articles in the scientific literature and also incorporated into an inquiry-based instructional webquest to help high school students understand biosphere-atmosphere research in the context of global climate change. This webquest would become part of a library of similar educational resources at UMBS.