Collaborative Research: Unraveling the link between water ages and silicate weathering rates at the catchment scale

合作研究：揭示流域尺度的水年龄和硅酸盐风化速率之间的联系

• 批准号: 2308548
• 负责人: Adrian Harpold
• 金额: $ 2.54万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2308548&HistoricalAwards=false
• 关键词: Collaborative; Research; Unraveling; link; between

The interaction between water and minerals is a fundamental process that shapes and records memories of landscapes, generates water quality and nutrients to sustain ecosystems, and draws down atmospheric CO2 over longer timescales. In watersheds, water is fed into the landscape through rain and snow where it starts its journey along various paths in the subsurface. Along the path, water encounters and exchanges with minerals, incorporating chemicals liberated from the solids and transforming them into other forms in a process termed weathering. Eventually the water with its unique chemical signature is flushed from the system into nearby streams and groundwater springs. The conventional wisdom is that the longer water spends in contact with the surrounding subsurface, the more chemically evolved it becomes. Under this framework, the amount of weathering observed in a catchment should be inextricably linked with groundwater ages. Historically, this relationship has been difficult to fully evaluate. This project will use modern geochemical tools in tandem with advanced modeling approaches to advance our understanding of the relationship between groundwater ages and weathering fluxes in a montane catchment, Sagehen Creek Basin, located in the Central Sierra Nevada mountains in California. This collaborative research effort will support two early career scientists, one PhD student, a field technician, and provide opportunities for undergraduate research. Researchers will collaborate with established Earth Science educators to launch a suite of educational products and initiatives to engage the broader public, high school students and instructors on hydrology and water quality themes. This research aims to better characterize the relationship between groundwater ages and silicate weathering rates at the catchment-scale through a combined hydrologic and geochemical approach. Silicate weathering reactions are uniquely coupled to catchment hydrology due to slow reaction kinetics; thus, solute generation is inherently dependent on the time fluids spend exposed to minerals. The project will develop and leverage a new, comprehensive water age (CFC, SF6, and 35S) and weathering (δ30Si, δ44Ca, and Ge/Si) tracer dataset to inform a coupled 2D physical transport hydrologic and isotope-enabled, multicomponent reactive transport model. The study will be conducted at Sagehen Creek Basin, a snowmelt driven, igneous, montane watershed sensitive to climatic. Sagehen is a widely studied site with several prior studies demonstrating a correlation between measured weathering-derived solute fluxes and groundwater residence times. This hybrid hydrological and geochemical approach will provide unprecedented insight into the synergistic relationship between fluid transit time and silicate weathering. The researchers plan to generate dynamic, continually evolving transit time distributions for water in response to both seasonal and event forcing, and through the incorporation of “fast”/shallow and “slow”/deeper groundwater components. This research further provides an opportunity to evaluate the utility of stable isotopes and trace element tracers that are sensitive to distinct reaction pathways, and to quantify how the extent of reactions can serve as “reaction clocks”. Findings will provide insight into persistent questions in critical zone science related to watershed hydrogeochemical response to climate change. This research is co-funded by the Division of Earth Sciences Geobiology and Low-Temperature Geochemistry Program and Hydrologic Sciences Program.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.

水与矿物质之间的相互作用是一个基本过程，它可以塑造和记录景观的记忆，产生水质和养分以维持生态系统，并在更长的时间表上降低大气二氧化碳。在分水岭中，水通过雨水和雪地供水到景观中，从而沿着地下的各种路径开始旅程。沿着路径，水与矿物质相遇和交换，将从固体释放的化学物质结合在一起，并在称为风化的过程中将其转化为其他形式。最终，具有独特化学签名的水从系统中冲入河流和地下水弹簧。传统的观点是，水与周围地下的接触时间越长，化学进化就变得越多。在此框架下，在集水区中观察到的天气量应与地下水年龄有着千丝万缕的联系。从历史上看，这种关系很难完全评估。该项目将与先进的建模方法同时使用现代地球化学工具，以促进我们对地下水时代和风化通量之间关系的理解，位于加利福尼亚州中部内华达州中部内华达山脉的Sagehen Creek Basin。这项合作研究工作将支持两位早期职业科学家，一名博士生，一名野外技术人员，并为本科研究提供了机会。研究人员将与知名的地球科学教育人员合作，发起一套教育产品和计划，以吸引更广泛的公众，高中生和教师，并就水文和水质主题进行培训。这项研究旨在通过一种合并的水文和地球化学方法更好地表征集水区尺度上地下水之间的关系。由于反应动力学缓慢，硅酸盐风化反应与流域水文学唯一耦合。因此，固体产生本质上取决于烟花花费的时间暴露于矿物质。该项目将开发并利用新的全面水时代（CFC，SF6和35S）和风化（Δ30SI，Δ44CA和GE/SI）示踪数据集，以告知耦合的2D物理传输水平和同位素启用的多功能，多功能，多功能，多功能电动传输模型。这项研究将在Sagehen Creek盆地进行，这是一种融化的驱动器，对山地对十字无二的敏感。 Sagehen是一个广泛的地点，有几项先前的研究表明，测得的风化衍生的固体通量与地下水停留时间之间存在相关性。这种杂化液压和地球化学方法将为流体运输时间和硅树脂风化之间的协同关系提供前所未有的见解。研究人员计划通过响应季节性和事件强迫来产生动态，不断发展的水分布，并通过掺入“快速”/浅水和“缓慢”/更深的地下水组件。这项研究进一步提供了评估对不同反应途径敏感的稳定同位素和痕量元素示踪剂的实用性，并量化反应程度如何用作“反应时钟”。研究结果将在关键区域科学中的持续性问题提供有关与流域水力化学对气候变化的反应有关的持续问题。这项研究是由地球科学划分和低温地球化学计划和水文科学计划共同资助的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优点和更广泛的影响来评估NSF的法定任务。