Collaborative research: Cascade “Ecohydromics” in the Amazonian Headwater System

合作研究：亚马逊河源头系统的级联“生态水文学”

• 批准号: 2106540
• 负责人: Loren Albert
• 金额: $ 15.26万
• 依托单位: West Virginia University Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2106540&HistoricalAwards=false
• 关键词: Collaborative; research; Cascade; Ecohydromics; Amazonian

Water movement through landscapes supports plant, animal, and human life, and through evaporation affects cloud processes and large-scale atmospheric circulation. The Amazon Basin cycles more water through streamflow and evaporation than any other contiguous forest in the world, and transpiration by trees – water taken up by roots and released to the atmosphere – is a critical part of this cycle. Understanding how plant roots, stems, and leaves interact with soil water to jointly regulate forest transpiration across landscapes is a critical knowledge gap, especially as climate changes. Forests are likely adapted to distinct soil moisture conditions in different parts of Amazonian landscapes. Specifically, forests on elevated plateaus with deep groundwater use water conservatively in order to tolerate drought, while those in wet valleys with shallow groundwater use water freely but may be poorly prepared for droughts of the future caused by the climate change. To understand landscape hydrology, rainforest compositions, and their susceptibility to global change, an integrated understanding of how water flows are regulated from upstream-to-downstream by plants and soil is required. This understanding is also critical for Earth-system modeling used to project the fate of Amazonian rainforests and quantify their future influence on climate. This project links diverse disciplines – plant physiology, ecology, hydrology – and integrates them into a model of landscape function. This project will also help train the next generation of scientists, both in the U.S. and Brazil, on interdisciplinary approaches in research, and through a summer school on computer modeling of vegetation and hydrologic processes. The project will develop a novel science outreach program connecting K-12 students to real-time Amazon tree data as well as a short class curriculum and a series of videos that teach students how to interpret data, understand the broader scientific context, and build a personal connection with scientists and real-time “talking trees” from the world’s most famous tropical forest.This project characterizes landscape variation in physiological and hydrological processes, and integrate observations with watershed modeling and hypothesis testing. Project activities focus on the spatially intricate mosaic of plateaus and valleys characteristic of central Amazonian headwater catchments. This research hypothesizes that: (H1) strong landscape variation in forest transpiration capacity arises from distinct characteristics of trees residing on plateaus (no root access to groundwater) and valleys (root access to groundwater) zones; (H2) previously unquantified “hybrid” soil hydraulics govern soil water fluxes and transit times connecting plateaus and valleys; and (H3) plateau forests influence the composition and function of valley forests by regulating subsurface water flows from higher to lower landscape areas. Study sites are located in the Brazilian Amazon: “KM34” near Manaus contains an instrumented watershed with more historical data and research on hillslope hydrology than any other watershed in a pristine wet tropical forest, and “KM67” near Santarém sits on a broad plateau with previously deployed deep soil moisture pits, allowing the isolation of processes typical for flat, elevated plateaus. Both sites contain eddy flux towers, canopy access walkways, and a rich history of ecological research and available datasets. A new valley subsite near KM67 will serve as an independent replicate of KM34 observations in valleys. Process-based models of vegetation ecophysiology, subsurface hydrology, and groundwater will be parameterized with observations of leaf physiology, tree morphological traits, soil moisture and physical properties, water table, and streamflow. These models will be integrated employing novel tools in probabilistic learning and uncertainty quantification for proper parameterization and validated with independent observations of tree sapflow, and ecosystem gas exchange and energy balance.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.

通过景观的水运动支持植物、动物和人类的生命，并通过蒸发影响云过程和大尺度大气环流。亚马逊流域通过溪流和蒸发循环的水比世界上任何邻近的森林都要多，而树木的蒸腾作用——树根吸收的水释放到大气中——是这一循环的关键部分。了解植物的根、茎和叶如何与土壤水分相互作用，共同调节景观中的森林蒸腾作用是一个关键的知识缺口，特别是在气候变化的情况下。森林很可能适应亚马逊不同地区不同的土壤湿度条件。具体来说，具有深层地下水的高寒高原上的森林为了耐受干旱而保守地用水，而具有浅层地下水的潮湿山谷中的森林则自由地用水，但可能对气候变化引起的未来干旱准备不足。为了了解景观水文学、雨林组成及其对全球变化的敏感性，需要对植物和土壤如何从上游到下游调节水流进行综合理解。这种理解对于用于预测亚马逊雨林命运和量化其未来对气候影响的地球系统建模也至关重要。该项目将不同的学科——植物生理学、生态学、水文学——联系起来，并将它们整合到景观功能模型中。这个项目还将帮助培训美国和巴西的下一代科学家，使他们掌握跨学科的研究方法，并通过一个关于植被和水文过程的计算机建模的暑期学校。该项目将开发一项新颖的科学推广计划，将K-12学生与实时亚马逊树木数据联系起来，并提供一个简短的课程和一系列视频，教学生如何解释数据，理解更广泛的科学背景，并与科学家和来自世界上最著名的热带森林的实时“会说话的树”建立个人联系。该项目描述了生理和水文过程中的景观变化，并将观测结果与流域建模和假设检验相结合。项目活动的重点是亚马孙中部水源集水区特征的高原和山谷在空间上错综复杂的镶嵌。本研究假设：（H1）森林蒸腾能力的强烈景观差异源于高原（根系无地下水通道）和山谷（根系无地下水通道）区树木的不同特征；（H2）以前未量化的“混合”土壤水力学控制土壤水通量和连接高原和山谷的过境时间；（H3）高原森林通过调节从地势较高的景观区向地势较低的景观区地下水流动来影响山谷森林的组成和功能。研究地点位于巴西亚马逊河流域：玛瑙斯附近的“KM34”包含一个仪器分水岭，其中有更多的历史数据和对山坡水文的研究，比原始潮湿热带森林中的任何其他分水岭都要多；桑塔姆姆附近的“KM67”位于广阔的高原上，以前部署了深土壤湿度坑，允许隔离平坦高架高原的典型过程。这两个地点都包含涡流通量塔、树冠通道、丰富的生态研究历史和可用的数据集。KM67附近的一个新的山谷子站点将作为KM34在山谷观测的独立复制。基于过程的植被生态生理、地下水文和地下水模型将通过对叶片生理、树木形态特征、土壤水分和物理特性、地下水位和水流的观测来参数化。这些模型将采用概率学习和不确定性量化的新工具进行整合，以获得适当的参数化，并通过独立的树木流量、生态系统气体交换和能量平衡观测进行验证。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。