Stream Corridor Hydrologic Controls on Carbon Dioxide Fluxes

河流和溪流越来越被认为是大气中二氧化碳（CO2）等温室气体的重要来源;然而，排放的全部规模和控制它们的过程仍然非常不确定。该项目将结合联合收割机创新领域的河流水文学和碳处理与先进的计算机模型，以提高我们的能力，预测和规模流CO2通量。这项研究的结果将促进我们对全球碳循环重要组成部分的理解，并提高监测未来变化的能力，生成的计算机模型将公开提供。这项研究还将包括一名博士生和本科生研究员的培训，它将作为一个为期一天的教育模块的重点，通过落基山生物实验室的夏季野外生物学课程，为不同群体的高中生。该项目的主要目标是开发河流走廊水文过程的定量模型，其对流域水平流CO2通量的控制，以及它们的时空变异模式。通过对科罗拉多洛矶山脉上东河流域的密集实地监测，该项目将实现若干研究目标：（1）利用高分辨率温度绘图和地球化学特征直接观测地下水流入溪流的情况，以了解它们对CO2通量的贡献以及通过连通性和流动路径变化驱动时空变化的作用;（2）通过一系列河段规模的监测工作和示踪剂释放实验，理清水柱和潜流带来源之间的流中CO2产生，并说明控制CO2与潜流带交换的主要过程;（3）结合地下水输入和河流廊道生产的基于过程的表示，沿着运输和湍流气体交换，该奖项反映了NSF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。

Rivers and streams are increasingly recognized as important sources of greenhouse gases such as carbon dioxide (CO2) to the atmosphere; however, the full magnitude of emissions and the processes that control them remain highly uncertain. This project will combine innovative field characterizations of stream hydrology and carbon processing with advanced computer models to improve our ability to predict and scale stream CO2 fluxes. Results of this research will advance our understanding of an important component of the global carbon cycle and the ability to monitor changes into the future, and generated computer models will be made publicly available. This research will also comprise the training of a PhD student and undergraduate researcher, and it will serve as the focus of a 1-day educational module for a diverse group of high school students through the Rocky Mountain Biological Laboratory’s summer Field Biology course.The primary objective of this project is to develop quantitative models of stream corridor hydrologic processes, their controls on watershed-level stream CO2 fluxes, and their spatial and temporal modes of variability. Through intensive field monitoring of the upper East River watershed in the Colorado Rocky Mountains, the project will address a number of research goals: (1) Provide direct observations of groundwater inputs to streams using high resolution temperature mapping and geochemical characterization to understand their contributions to CO2 fluxes and role in driving spatiotemporal variability through connectivity and flowpath variations; (2) Disentangle in-stream CO2 production between water-column and hyporheic zone sources and characterize the dominant processes that control CO2 exchange with the hyporheic zone through a series of reach-scale monitoring efforts and tracer release experiments; (3) Incorporate process-based representations of groundwater inputs and stream corridor production, along with transport and turbulent gas exchange, into reach- and watershed-scale stream network models of CO2 to improve predictions and monitoring of stream concentrations and fluxes.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.