CAREER: Balancing the global alkalinity cycle by improving models of river chemistry

职业：通过改进河流化学模型平衡全球碱度循环

• 批准号: 2338139
• 负责人: Mark Torres
• 金额: $ 61.29万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2025
• 资助国家: 美国
• 起止时间: 2025-01-01 至 2029-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2338139&HistoricalAwards=false
• 关键词: CAREER; Balancing; global; alkalinity; cycle

The water flowing in a river today is largely composed of rainwater that fell in the past and traveled underground before arriving at the river channel. The amount of time this transit takes is also the amount of time available for chemical reaction to occur. At the same time, the exact path that rain takes through watersheds - whether through shallow soils or deep, fractured bedrock - influences which reactions occur and at what rates. Consequently, observations of river water chemistry can be described equally well by models that attribute all variation to changes in either flow paths or flow rates. This ambiguity is problematic as the predicted effects of climate change on water resources are different depending upon the exact processes governing flow and reaction. To provide new insights into the controls on river water chemistry, this project will develop new approaches for analyzing variations in chemistry over time to separate the effects of flow paths from flow rates. The project will engage undergraduate students through an engineering design course, internships, and public outreach on local water quality issues.This work will leverage the information content of time-series data to constrain the coupled timescales of subsurface water transit and solute acquisition. To avoid some of the assumptions embedded in past work, non-parametric approaches will be used to infer geochemical kinetics and solute generation mechanisms. After being validated against 2-D numerical and analog experiments, the analysis approach will be used to elucidate the role of Critical Zone structure in the climate-weathering feedback as well as account for the non-linear behavior of trace element and isotopic proxies to improve mixing models. The results of these applications will be used to inform a new global analysis of weathering processes and their implications for planetary habitability with a timescale-agnostic framework for comparing terrestrial and marine systems. To lower barriers to collecting time-series data, undergraduate engineering design teams will develop a design-for-purpose autosampler. To help engage more undergraduate students in geoscience research, the project will develop a new, outreach-based course on local water quality issues.This project is co-funded by the Hydrologic Sciences and Geobiology & Low-Temperature Geochemistry programs.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.

今天河流中流动的水主要是由过去降落的雨水组成，在到达河道之前，这些雨水在地下流动。这种转变所花费的时间也是化学反应发生的时间。与此同时，雨水通过流域的确切路径--无论是通过浅层土壤还是深层破碎的基岩--都会影响哪些反应发生以及速度。因此，河水化学的观测结果同样可以通过模型来描述，模型将所有变化归因于流动路径或流速的变化。这种模糊性是有问题的，因为气候变化对水资源的预测影响是不同的，取决于控制流动和反应的确切过程。为了提供对河流水化学控制的新见解，该项目将开发新的方法来分析化学随时间的变化，以将流动路径的影响与流速分开。该项目将通过工程设计课程、实习和公众宣传来吸引本科生参与当地的水质问题。这项工作将利用时间序列数据的信息内容来约束地下水传输和溶质采集的耦合时间尺度。为了避免嵌入在过去的工作中的一些假设，非参数的方法将被用来推断地球化学动力学和溶质生成机制。在对二维数值模拟实验进行验证后，分析方法将用于阐明临界带结构在气候-风化反馈中的作用，以及解释微量元素和同位素替代物的非线性行为，以改进混合模型。这些应用程序的结果将用于提供信息的风化过程及其对行星可居住性的影响与时间尺度不可知的框架比较陆地和海洋系统的一个新的全球分析。为了降低收集时间序列数据的障碍，本科工程设计团队将开发一种专用自动采样器。为了帮助更多的本科生参与地球科学研究，该项目将开发一个新的，基于外展的课程，对当地的水质问题。这个项目是由水文科学和地球生物学低温地球化学计划共同资助。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。