The Impact of Environmental Perturbations on Biogenic Monoterpene Emissions and Their Implications to Secondary Organic Aerosol

众所周知，森林会排放大量的活性挥发性有机化合物(VOC)，这些化合物会产生称为二次有机气溶胶(SOA)的小颗粒。这些星云散射阳光和种子云，这使得它们对地球的辐射和能量收支很重要。然而，这些过程是高度不确定的，目前的气候模型没有捕捉到这些过程。此外，二氧化碳增加引起的气候变化预计将改变温度和降水模式，这将影响森林中VOC和SOA的生产。对这些变化的反应可以是截然不同的、非相加的和非线性的，对于这些生物气候反馈是否会加剧或缓和人为气候强迫，存在相互矛盾的证据。该建议通过使用最先进的测量方法对植物进行有针对性的实验室研究，解决了这一重要的不确定性。该项目实施了植物室内控制研究，以测量快速生长的尼古丁植物在非生物胁迫条件下的VOC排放和SOA形成。它将制定协议来测量非生物胁迫下植物BVOC的排放，并调查二氧化碳和温度升高对植物排放的综合影响。这项研究将开发一套20个植物室，用于快速生长的烟草植物。然后，它将调查20种相同(即遗传克隆)植物在相同条件(环境二氧化碳+高温)下至少一个月的VOC排放和SOA产量结果的差异。最后，它将进行一个双因素短期扰动实验，二氧化碳和温度扰动(+400ppmv和+5℃)将分别施加，并结合使用，以检验组合非生物胁迫以非线性方式改变VOC排放的假设。

Forests are known to emit substantial amounts of reactive volatile organic compounds (VOC) that produce small particles called secondary organic aerosols (SOAs). These SOAs scatter sunlight and also seed clouds making them important for the earth's radiation and energy budget. However, these processes are highly uncertain and not captured in current climate models. Furthermore, climate change from increasing carbon dioxide is expected to alter temperatures and change precipitation patterns that will impact VOC and SOA production from forests. The responses to these changes can be distinct, non-additive and non-linear and there is conflicting evidence on whether these biogenic climate feedbacks will exacerbate or moderate anthropogenic climate forcing. The proposal addresses this important uncertainty with targeted laboratory studies of plants using state of the art measurements.This project implements control studies of plant chambers for measurement of VOC emissions and SOA formation from fast growing nicotine plants under abiotically stressed conditions. It will develop protocols to measure plant BVOC emissions under abiotic stress and also investigate the combined impact of elevated CO2 and temperature on plant emissions. The study will develop a set of 20 plant chambers for use with fast growing Nicotiana plants. It will then investigate the variance in VOC emission and SOA yield results for 20 identical (i.e. genetic clones) plants under identical conditions (ambient CO2 + elevated temperature) for at least one month. Finally it will perform a two-factor, short-term perturbation experiment, with CO2 and temperature perturbations ( +400 ppmv and +5 deg C) will be applied both separately and combined to test the hypothesis that combined abiotic stresses change VOC emissions in non-linear manners.