EAR-PF: Quantifying methane reactivity and turnover in the subterranean estuary: combined in-situ and ex-situ isotope tracer approaches

EAR-PF：量化地下河口的甲烷反应性和周转：原位和异位同位素示踪方法相结合

• 批准号: 2204584
• 负责人: Stephanie Wilson
• 金额: $ 18万
• 依托单位: Wilson, Stephanie J
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204584&HistoricalAwards=false
• 关键词: EAR; PF; Quantifying; methane; reactivity

At the interface of land and sea, subterranean estuaries (STEs) serve as subsurface transition zones. STEs can support a variety of biogeochemical reactions that influence concentrations and transport of nutrients and carbon. High concentrations of methane (CH4), an important greenhouse gas and major player in the global carbon cycle, has been observed in the coastal subsurface. However, the way that this CH4 pool is transformed and transported within STEs remains unconstrained. This study will provide a novel understanding of how CH4 is cycled in the subsurface, specifically its turnover time and the transformations controlling concentration and fate, just prior to release to surface waters. These research products represent fundamental constraints, which are critical to determining fluxes of CH4 from the subsurface and the role of STEs in the global carbon cycle. Dr. Stephanie Wilson will build upon previous work conducted by multiple research groups along the east coast, to further scientific understanding of CH4 cycling and exchanges between the subsurface and the overlying water or atmosphere. The results of this study will be directly applicable to ongoing research and modeling efforts, providing fundamental information about CH4 to inform calculations of fluxes and emissions from the subsurface, with implications beyond the fields of groundwater hydrology and geochemistry. Moreover, the project is designed to optimize the reach of its findings and develop human capital. Results will be disseminated at conferences, departmental seminars, and published in scientific journals. Dr. Wilson will incorporate undergraduate students in both field and lab research efforts with the goal of creating an inclusive environment that promotes personal growth and scientific learning. Research findings will be made available to the public via several avenues designed to engage K-12 students, educators, the local community, and the larger public via a variety of engagement activities.Subterranean estuaries (STEs) are important transition zones within the subsurface that host a variety of biogeochemical reactions. They are dynamic systems influenced by both watershed and tidal drivers. Within the STE, biogeochemical reactions control the speciation and concentration of subsurface nutrients and carbon, therefore, they determine the fate of these analytes when they are released to the overlying water and/or the atmosphere. There is a growing body of literature reporting high concentrations of methane (CH4) in the subsurface along coastal margins; however, the mechanisms of transformation and transport of this pool remain unknown. There is, therefore, a limited understanding of how this subsurface CH4 pool exchanges with the overlying water and/or atmosphere. The STE may act as a passive interface whereby CH4 generated within the aquifer moves through the STE conservatively, or CH4 inventories may be modified via consumption or production within the STE on timescales faster than net transport. The lack of context and defined constraints controlling the STE CH4 pool represents a knowledge gap essential to determining fluxes of CH4 from the subsurface and the role STEs play in the global carbon cycle. The project includes examination of the transformations and transport of CH4 in STEs using a three-pronged approach that combines in situ and ex situ stable isotope labeled tracer experiments with the characterization of subsurface geochemical gradients. The work addresses rates and mechanisms. Tracer experiments will be conducted in several STEs along the east coast of the US parsed into the two dominant coastal STE types, wetland and sandy, and spanning a spectrum of hydrologic forcings. Results from this study will provide a novel understanding of how CH4 is cycled in the subsurface, specifically its turnover time and the transformations controlling concentration and fate, just prior to release to surface waters. Specifically, this work will provide information regarding the CH4 pool rate of turnover, transformation, and transport. These products represent fundamental constraints, which are critical to determining fluxes of CH4 from the subsurface and the role of STEs in the global carbon cycle. This novel information will be directly applicable to ongoing research determining the role of transition zones in greenhouse gas dynamics and global climate change. Research products will provide fundamental information, which will reach beyond the fields of groundwater hydrology and geochemistry. Results will provide fundamental constraints on modeling atmospheric fluxes of CH4 meditated by the STE and the project is designed to optimize the reach of its findings and develop human capital.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.

在陆地和海洋的界面，地下河口（Stes）充当地下过渡区。 Stes可以支持各种影响养分和碳浓度和运输的生物地球化学反应。高浓度的甲烷（CH4）是在沿海地面上观察到的全球碳周期中重要的温室气体和主要参与者。但是，该CH4池在Stes中进行转换和运输的方式仍然不受限制。这项研究将提供对CH4在地下中如何循环的新了解，特别是其周转时间以及控制浓度和命运的转换，就在释放到地表水之前。这些研究产品代表了基本的约束，这对于从地下和Stes在全球碳循环中的地下和STE的作用中确定CH4的通量至关重要。斯蒂芬妮·威尔逊（Stephanie Wilson）博士将建立在东海岸多个研究小组进行的以前的工作，以进一步科学地理解地下和上面的水或氛围之间的CH4骑行和交流。这项研究的结果将直接适用于正在进行的研究和建模工作，提供有关CH4的基本信息，以告知从地下的通量和排放的计算，其含义超出了地下水水文和地球化学领域。此外，该项目旨在优化其发现的影响力并发展人力资本。结果将在会议，部门研讨会上传播，并在科学期刊上发布。威尔逊博士将在现场和实验室研究工作中纳入本科生，以创造一个包容性的环境，以促进个人成长和科学学习。研究发现将通过几种旨在通过各种参与活动与K-12学生，教育工作者，当地社区和较大公众与K-12学生，教育者，当地社区和较大公众互动的途径提供给公众。SubterraneanEstuaries（STES）是亚种的重要过渡区，可容纳各种生物地球化学反应。它们是受分水岭和潮汐驱动因素影响的动态系统。在Ste中，生物地球化学反应控制地下营养素和碳的形成和浓度，因此，当这些分析物被释放到上面的水和/或大气中时，它们决定了这些分析物的命运。越来越多的文献报道了沿海边缘的地下中高浓度的甲烷（CH4）。但是，该池的转换和运输机制仍然未知。因此，对这个地下CH4池如何与上覆的水和/或大气交换的情况有限。 Ste可以充当一个被动界面，从而在含水层中生成的CH4保守地移动，或者可以通过在Ste上的消费或生产来修改CH4库存比净运输更快。缺乏控制STE CH4池的上下文和定义约束，这代表了从地下确定CH4的通量以及Stest在全球碳循环中所扮演的角色所起的知识差距。该项目包括使用三方面的方法检查CH4在Stes中的转换和运输，该方法结合了原位和原位稳定的同位素标记的示踪剂实验，并具有地下地球化学梯度的表征。该工作解决了费率和机制。示踪剂实验将在美国东海岸的几个Stes中进行，分解为两种主要的沿海Ste类型，即湿地和桑迪，并跨越了一系列水文强迫。这项研究的结果将提供对CH4在地下中如何循环的新了解，尤其是其离职时间以及控制浓度和命运的转化，在释放到地表水之前。具体而言，这项工作将提供有关CH4池的营业额，转换和运输的信息。这些产品代表了基本的约束，这对于从地下和Stes在全球碳循环中的地下和STE的作用中确定CH4的通量至关重要。该新型信息将直接适用于正在进行的研究，以确定过渡区在温室气体动态和全球气候变化中的作用。研究产品将提供基本信息，这些信息将超出地下水水文学和地球化学领域。结果将为建模CH4的大气通量提供基本的限制，该项目旨在优化其发现的影响力并发展人力资本。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来获得支持的。