CAREER: Unearthing the Role of Belowground Biology in Biosphere-Atmosphere Volatile Organic Compound (VOC) Exchange

挥发性有机化合物（VOC）通过自然和人为过程排放到大气中，对空气质量和气候起着重要作用。挥发性有机化合物的一个重要自然来源是植物，但了解各自的土壤如何促进挥发性有机化合物的排放仍然难以捉摸。本研究的总体研究目标是揭示VOC在地下循环的微生物过程，描述气候变化如何影响VOC排放。大气化学和生态系统科学的跨学科专业知识通过合作得到保障，亚利桑那大学有必要的基础设施来开展必要的实地和实验室研究。该计划为学生提供学习和从事跨学科研究和教育的机会，预计在五年的项目中直接影响约100名学生。该项目由大气与地球空间科学部大气化学（ATC）项目和环境生物学部生态系统科学（ES）集群共同评审和资助。研究目标集中于土壤中VOC代谢的识别、分离和约束，具体而言：(1)识别和整理土壤中驱动VOC代谢的微生物和根系途径；(2)分离控制土壤中VOC循环的地下根-微生物相互作用；(3)从基因尺度到生态系统尺度对VOC地下循环的约束。在生物圈2号的实验室土壤柱和野外规模的对照实验中，对微生物分离物挥发性有机化合物的产生和消耗进行了新的测量。挥发性有机化合物代谢途径从不同的数据流被收集在一个新的微生物挥发性数据库。为了区分根系对土壤净VOC交换的贡献，利用13CVOC在线测量实现了13C稳定同位素脉冲标记。最后，在控制生态系统干旱试验中，收集了新的土壤表层和地下VOC数据，以建立土壤VOC过程模型，并对VOC从基因到生态系统的地下循环进行了研究。研究结果将有助于了解挥发性有机化合物生物圈-大气交换的地下驱动因素，从而改善对大气影响和挥发性有机化合物生物反馈的预测。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Volatile organic compounds (VOC) are emitted into the atmosphere through natural and anthropogenic processes and play an important role in air quality and climate. One significant natural source of VOCs is from plants yet understanding how respective soils contribute to VOC emissions remains elusive. The overarching research goal of this study is to unearth microbial processes of VOC cycling below ground that describe how a changing climate may affect VOC emissions. Interdisciplinary expertise in atmospheric chemistry and ecosystem science is secured through collaborations, and necessary infrastructure is available at the University of Arizona to carry out essential field and laboratory studies. This plan provides opportunities for students to learn and engage in research and education across disciplinary boundaries and anticipates to directly impact ~100 students over the five-year project. This project was co-reviewed and co-funded by the Atmospheric Chemistry (ATC) Program in the Division of Atmosphere and Geospace Sciences and the Ecosystem Science (ES) Cluster in the Division of Environmental Biology.Research objectives focus on identifying, separating, and constraining VOC metabolism in soil, and specifically: (1) identifying and collating microbial and root pathways that drive VOC metabolism in soil; (2) separating belowground root-microbe interactions governing VOC cycling in soil; and (3) constraining belowground VOC cycling from gene to ecosystem scales. New measurements of VOC production and consumption by microbial isolates are performed in controlled experiments in laboratory soil columns and at field scale in Biosphere 2. VOC metabolic pathways from diverse data streams are gathered in a new Microbial Volatilome Database. To distinguish root-derived contributions to net soil VOC exchange 13C stable isotope pulse labeling is implemented with online 13CVOC measurements. Finally, new soil surface and subsurface VOC data is collected in a controlled ecosystem drought experiment to advance soil VOC process models and scale belowground VOC cycling from genes to the ecosystem. Results will aid in understanding belowground drivers of VOC biosphere-atmosphere exchange that will improve projections of atmospheric impacts and biological feedbacks of VOCs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.