Collaborative Research: MSB-ENSA: Leveraging NEON to Build a Predictive Cross-scale Theory of Ecosystem Transpiration

水是维持大陆生态系统的重要资源。陆地植物通过从土壤和地下水中提取水分并在生长过程中释放到大气中，在大陆和大气之间的水循环中起着至关重要的作用。现有数据表明，这一过程，即蒸腾作用，占全球从大陆到大气的水转移的一半以上。令人惊讶的是，关于蒸腾作用的蒸腾量，不同类型的植物和生态系统如何控制蒸腾作用，以及蒸腾作用如何塑造生态系统的特性，人们知之甚少。该奖项支持一个由生态学家、地球和大气科学家以及工程师组成的跨学科小组，首次对美国各地的植物蒸腾作用进行估计，并利用这些数据开发模型，改进对未来植物用水的预测。该团队将开发有利于科学界的新技术和数据集，并开展跨学科的研究生培训，以培养多样化的下一代科学家，以应对生态和数据科学挑战。项目小组将利用国家生态观测网提供的各种数据产品，主要侧重于水蒸气和二氧化碳的稳定同位素比率。同位素比值提供了控制植物叶片与大气之间气体交换的物理过程的综合测量。该网络在美国各地部署的传感器套件提供了第一个标准化数据集，可以基于同位素估算不同大陆生态系统的蒸腾作用。项目团队将根据该网络的传感器数据开发新的校准程序和数据产品，并将其分发给更广泛的研究界使用。这些数据将与该网络收集的其他数据和项目小组从实地活动获得的信息结合起来，利用从个别地块到大陆尺度的一系列空间尺度的分析，确定生态系统结构和植物调节气体交换如何控制蒸腾作用。这些知识将被整合并用于测试反映研究生态系统中功能特征和结构特性的潜在分布的植物用水模型。这些模型将用于检查蒸腾和生态系统用水的潜在敏感性。在其工作过程中，该项目将开发和传播新的测量和数据分析方法以及广泛应用于研究人员的数据集，并将支持空间科学研究生短期课程。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。

Water is a critical resource that sustains continental ecosystems. Land plants play a critical role in the cycling of water between the continents and atmosphere by extracting water from soils and groundwater and releasing it to the atmosphere as they grow. Existing data suggest that this process, transpiration, accounts for more than half of the global transfer of water from the continents to the atmosphere. Surprisingly little is known about how much water is transpired, how different types of plants and ecosystems govern transpiration, and how properties of ecosystems are shaped by transpiration. This award supports an interdisciplinary group of ecologists, Earth and atmospheric scientists, and engineers to make estimates of plant transpiration across the United States for the first time and use these data to develop models and improve predictions of future plant water use. The team will develop new techniques and datasets benefitting the scientific community and conduct interdisciplinary graduate student training to prepare diverse, next-generation scientists to tackle ecological and data science challenges.The project team will work with a wide range of data products produced by the National Ecological Observatory Network, with a primary emphasis on stable isotope ratios of water vapor and carbon dioxide. Isotope ratios provide an integrated measure of physical processes controlling gas exchange between plant leaves and the atmosphere. The suite of sensors deployed by the Network across the USA provides the first standardized dataset enabling isotope-based estimation of transpiration across a diverse range of continental ecosystems. The project team will develop new calibration procedures and data products from the Network's sensor data and distribute these for use by the broader research community. These data will be integrated with other data collected by the Network and information from field campaigns by the project team, using analysis at a range of spatial scales from individual plots to continental scales to determine how ecosystem structure and plant regulation of gas exchange control transpiration. This knowledge will be integrated into and used to test models for plant water use that reflect the underlying distribution of functional traits and structural properties within the study ecosystem. The models will be used to examine the potential sensitivities of transpiration and ecosystem water use. During the course of its work, the project will develop and disseminate new measurement and data analysis approaches and datasets of broad use to researchers, and will support a graduate short course in spatial sciences.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.