Collaborative Research: EAR-Climate: Hydraulic and Hydrologic Regulation of Greenhouse Gas Emissions from Forest Soils and Trees and Detection With Radon As A Novel Tracer

合作研究：EAR-气候：森林土壤和树木温室气体排放的水力和水文调节以及用氡作为新型示踪剂进行检测

• 批准号: 2210783
• 负责人: James Megonigal
• 金额: $ 30.75万
• 依托单位: Smithsonian Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2210783&HistoricalAwards=false
• 关键词: Collaborative; Research; EAR; Climate; Hydraulic

The goals of this project are to better understand the role of trees in the global water and methane cycles and to attract elementary-school age students to environmental science through hands-on activities about water and trees. Methane is a potent greenhouse gas, causing about 30 times as much global warming per molecule as carbon dioxide. It is currently known that methane can be emitted from the trunks of trees, but it is unknown if the methane originates in the soil and is transported into the tree along with tree water uptake from below ground, or if the methane originates inside the tree. Understanding what water and environment factors influence methane emissions from trees can improve climate predictions and may help people manage forests and forested wetlands deliberately to reduce their natural methane emissions. The project will also work with a local elementary school serving talented and gifted students primarily from underrepresented groups (Black, Latinx). About 200 second-grade students will visit American University, where they will learn about watersheds, trees, and sustainability and participate in activities to develop a science identity.This research will use radon as a tracer of the movement of water and gases through trees. Radon is an established tool for studying water flows and gas exchange in the ocean, estuaries, rivers, soil, and groundwater. Radon, methane, and water fluxes from trees will be simultaneously measured across a wetland-upland gradient to determine whether the methane emitted from trees comes from soil water or is produced within the tree. Soil moisture, water potential, soil methane and radon concentrations, water table height, stomatal conductance, and sap flow will be measured concurrently to delineate the relationships between tree physiology, water flows, and stem gas emissions and to distinguish topographic effects. Field data will be used to develop numerical models that simulate dynamic gas transport through the soil-plant-atmosphere continuum, account for both dissolved gas and bubbles, and include both daytime and nighttime transient water potential gradients and transport. Finally, the results will be scaled up to assess how direct and indirect effects of climate change (e.g., temperature increase, sea level rise, changes in precipitation patterns, soil moisture, and tree water use, shift of some coastal forests from upland to wetland) may affect tree methane emissions.This award is co-funded by the Hydrologic Sciences and Instrumentation and Facilities programs in the Division of Earth Sciences, as well as the Ecosystem Science program in the Division of Environmental Biology.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.

该项目的目标是更好地了解树木在全球水和甲烷循环中的作用，并通过有关水和树木的实践活动吸引小学生学习环境科学。甲烷是一种强效温室气体，每分子造成的全球变暖程度约为二氧化碳的 30 倍。目前已知甲烷可以从树干中排放出来，但尚不清楚甲烷是否源自土壤并随着树木从地下吸收的水分输送到树木中，或者甲烷是否源自树内部。了解哪些水和环境因素影响树木的甲烷排放可以改善气候预测，并可以帮助人们有意识地管理森林和森林湿地，以减少自然甲烷排放。该项目还将与当地一所小学合作，为主要来自代表性不足的群体（黑人、拉丁裔）的才华横溢的学生提供服务。大约 200 名二年级学生将参观美利坚大学，在那里他们将了解流域、树木和可持续性，并参与发展科学认同的活动。这项研究将使用氡气作为水和气体通过树木运动的示踪剂。氡气是研究海洋、河口、河流、土壤和地下水中水流和气体交换的既定工具。将在湿地-高地梯度上同时测量树木的氡气、甲烷和水通量，以确定树木排放的甲烷是来自土壤水还是在树木内部产生。同时测量土壤湿度、水势、土壤甲烷和氡浓度、地下水位高度、气孔导度和液流，以描绘树木生理、水流和茎气体排放之间的关系，并区分地形影响。现场数据将用于开发数值模型，模拟通过土壤-植物-大气连续体的动态气体传输，解释溶解气体和气泡，并包括白天和夜间瞬态水势梯度和传输。最后，结果将扩大规模，以评估气候变化的直接和间接影响（例如，气温升高、海平面上升、降水模式的变化、土壤湿度和树木用水、一些沿海森林从高地向湿地的转变） ）可能会影响树木甲烷排放。该奖项由地球科学部的水文科学和仪器和设施计划以及环境生物学部的生态系统科学计划共同资助。该奖项反映了 NSF 的法定使命和已经通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。