ORE-CZ: Ecohydrological Controls on Soil Respiration and the Apparent Respiratory Quotient Across a Dynamic Storage Gradient

ORE-CZ：动态蓄水梯度下土壤呼吸和表观呼吸商的生态水文学控制

• 批准号: 2227975
• 负责人: John Knowles
• 金额: $ 20万
• 依托单位: Chico State Enterprises
• 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: 2022-11-01 至 2025-10-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2227975&HistoricalAwards=false
• 关键词: ORE; CZ; Ecohydrological; Controls; Soil

Soils contain more carbon than vegetation and the atmosphere combined, and soil respiration describes the transfer of soil carbon to the atmosphere via plant roots and microbes. As air temperatures rise and water availability changes, changes in the soil respiration flux represent significant potential feedback to the greenhouse effect and the magnitude of future warming. Accordingly, this project will take advantage of soil carbon dioxide (CO2) and oxygen data provided by the NSF-funded Dynamic Water Critical Zone (CZ) Thematic Cluster to quantify the variability of soil respiration and the fate of soil-produced CO2 with respect to changes in soil development, vegetation, and topography that mediate water availability across representative semi-arid montane elevation and climatic gradients. The research will support career training and learning experiences for graduate and undergraduate students at California State University, Chico, which is a federally designated Hispanic-Serving Institution (HSI), a Primarily Undergraduate Institution, and where more than 50% of the student population are first generation college students. A “bedrock to treetop” CZ approach considers feedbacks between soil, water, landscape position, and living organisms at Earth’s surface. Dynamic water storage - water with intermediate residence times - sustains CZ function between precipitation events, and is critically important to soil respiration and carbon cycling. As a result, the main objective of this research is to quantify the importance of dynamic water storage to the integral CZ functions of soil respiration and the Apparent Respiratory Quotient (ARQ) that determines the degree to which soil-produced CO2 is respired directly to the atmosphere versus transported laterally or vertically with infiltrating water. The investigators will specifically test the hypotheses that (1) soil respiration and the ARQ will be proportional to the volume of dynamic water storage in the root zone, and (2) that dynamic water storage capacity will interact with complex terrain to determine the variability of soil respiration and ARQ over space and time. Because research activities will be replicated and integrated across multiple watersheds, they will allow for evaluation of the transferability of process-based information, toward a more comprehensive understanding of CZ carbon cycling with direct implications for the climate change mitigation potential of semi-arid montane ecosystems. This project was supported with co-funding of the HSI Program which aims to enhance undergraduate STEM education, broaden participation in STEM, and build capacity at HSIs. Achieving these aims, given the diverse nature and context of the HSIs, requires innovative approaches that incentivize institutional and community transformation and promote fundamental research (i) on engaged student learning, (ii) about what it takes to diversify and increase participation in STEM effectively, and (iii) that improves our understanding of how to build institutional capacity at HSIs.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.

土壤中的碳含量比植被和大气的总和还多，土壤呼吸描述了土壤碳通过植物根系和微生物转移到大气中的过程。随着气温升高和可用水量的变化，土壤呼吸通量的变化代表了对土壤的重要潜在反馈。因此，该项目将利用 NSF 资助的动态水临界区 (CZ) 主题集群提供的土壤二氧化碳 (CO2) 和氧气数据来量化土壤呼吸的变化和命运土壤产生的二氧化碳与土壤发育、植被和地形变化的关系，这些变化调节了代表性半干旱山地海拔和气候梯度的水供应。该研究将为加州州立大学研究生和本科生的职业培训和学习体验提供支持。奇科，这是一所联邦政府指定的西班牙裔服务机构 (HSI)，主要是本科院校，超过 50% 的学生人口是第一代大学生。考虑了地球表面土壤、水、景观位置和生物体之间的反馈——具有中间停留时间的水——维持降水事件之间的 CZ 功能，并且对土壤呼吸和碳循环至关重要。这项研究的主要目的是量化动态水储存对土壤呼吸积分 CZ 函数和表观呼吸商 (ARQ) 的重要性，ARQ 决定土壤产生的二氧化碳直接呼吸到土壤的程度。研究人员将专门测试以下假设：(1) 土壤呼吸和 ARQ 将与根区动态储水量成正比，以及 (2) 动态储水量。将与复杂地形相互作用，以确定土壤呼吸和 ARQ 在空间和时间上的变化，因为研究活动将在多个流域进行复制和整合，因此它们将允许评估基于过程的信息的可转移性，以获得更全面的理解。 CZ碳该项目得到了 HSI 计划的共同资助，该计划旨在加强本科生 STEM 教育，扩大 STEM 的参与，并建设 HSI 的能力。鉴于 HSI 的不同性质和背景，目标需要创新的方法来激励机构和社区转型并促进基础研究 (i) 关于学生的参与学习，(ii) 关于如何实现多样化和增加参与有效地促进 STEM，(iii) 提高我们对如何在 HSI 建设机构能力的理解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。