Collaborative Research: Determining the role of hydraulic redistribution regimes in the critical zone - an experimental and modeling synthesis

协作研究：确定关键区域水力再分配机制的作用 - 实验和建模综合

• 批准号: 1417444
• 负责人: Praveen Kumar
• 金额: $ 22.84万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1417444&HistoricalAwards=false
• 关键词: Collaborative; Research; Determining; role; hydraulic

Understanding and predicting interactions between aboveground and belowground ecohydrologic processes is challenging. Roots play an important role in linking aboveground plant ecophysiological processes, such as carbon, water, and energy exchange with the atmosphere, and the belowground processes associated with soil moisture and carbon, and microbial and nutrient dynamics. Interestingly, root water movement is not always unidirectional; plants create pathways for preferential water movement through a phenomenon called "hydraulic redistribution", by which water moves downward through the roots during wet periods but upward during drier periods. This project will study such hydraulic redistribution. The study will both provide insights for dryland regions and enable broader generalizations regarding the interaction between groundwater, roots, and aboveground assemblages and their role in whole-ecosystem performance. The salient aspect of this study is the coupling between field research and modeling to enable hypotheses testing and provide an upscaling framework from site-based studies. Given projections of a warmer climate, there has been a rapid expansion in scientific interest in how ecosystems will respond to periods of prolonged stress. This research will help address this critical issue.The scientific objective of the project is to systematically examine the role of hydraulic redistribution by roots as a mechanism for facilitating aboveground-belowground linkages that drive water and carbon dynamics, and the development of emergent spatial patterns of soil moisture and vegetation distribution. Field-based activities will be conducted at two sites in southern Arizona: a riparian site where precipitation inputs are augmented with belowground water sources and an upland site that lacks this secondary water pool. This research will advance the theory for understanding the interaction of aboveground and belowground ecohydrological processes using a model that mechanistically resolves the related processes. Coupled modeling and field experimentation and monitoring of root and stem sap flux, soil, carbon, whole-plant, and ecosystem-scale (via eddy covariance tower) water and carbon fluxes will mutually inform each other to provide detailed insights at a range of scales. Results from this study will be presented in kiosks on the tour route of Biosphere 2 that sees over 100,000 visitors per year that include K-12 students to retirees.

理解和预测地上和地下生态水文过程之间的相互作用是具有挑战性的。根在连接地上植物生态生理过程（例如碳，水和能量交换）以及与大气以及与土壤水分和碳以及微生物和养分动力学相关的地下过程中起着重要作用。有趣的是，根水流动并不总是单向的。植物创造了通过称为“液压重新分布”现象的现象，为优先的水运动创造了途径，在潮湿时期，水通过根部向下移动，但在干燥时期内向上。该项目将研究这种液压重新分布。这项研究都将为旱地地区提供见解，并就地下水，根和地上组合之间的相互作用及其在整个生态系统绩效中的作用进行更广泛的概括。这项研究的显着方面是实地研究与建模之间的耦合，以实现假设测试并提供基于站点的研究的升级框架。鉴于气候温暖的预测，科学兴趣在生态系统如何应对长时间压力时期的反应方面存在迅速的扩展。这项研究将有助于解决这一关键问题。该项目的科学目标是系统地检查根部通过根部重新分配的作用，作为促进地上阳光地面连接的机制，以驱动水和碳动态，以及土壤水分和植被分布的新兴空间模式的发展。基于现场的活动将在亚利桑那州南部的两个地点进行：一个河岸地点，其中降水投入以下面的水源和一个缺乏此二次水池的高地地点进行。这项研究将推进理论，以使用机械能够解决相关过程的模型来理解地上和地下生态水文过程的相互作用。耦合的建模和野外实验以及根和茎液的磁带，土壤，碳，全植物和生态系统规模（通过涡流协方差塔）的水和碳通量将相互告知，以在一系列尺度范围内提供详细的见解。这项研究的结果将在售货亭中在生物圈2的旅游路线上介绍，该途径每年将超过100,000名访客，其中包括K-12学生将退休。