CAREER: Transformation and Transport of Organic Carbon in the Colorado River-Reservoir System

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。河流是陆地和水生生态系统之间的动态联系。有机碳在河流中产生、消耗和转化的生物地球化学过程对于理解区域碳收支、河流水质控制以及最终向沿海地区输出陆地有机碳至关重要。我们对河流碳循环的基本理解主要基于原始河流的数据；然而，如今几乎所有河流都得到了优化供水、防洪和水力发电的管理。在科罗拉多河上，水坝和水库系统极大地改变了水动力学和地貌、水停留时间、颗粒负荷、光照条件和沉积物-水的相互作用。相对而言，这些储层对碳生物地球化学的影响知之甚少。该项目将评估单个流域内一系列特征良好的储层的陆地和河流碳的分布、组成和反应性。本项目整合了假设驱动的生物地球化学研究问题，最先进的分析方法和创新的教学策略，以解决三个基本研究要素：1。利用实地测量和实验室操作实验相结合的方法，为科罗拉多河系统制定区域碳预算。检查科罗拉多河系统中溶解有机碳和颗粒有机碳的组成、反应性和命运。通过实地教学提高地球科学学生的学习成果。纵向水采样、碳表征和生物地球化学过程研究，最终得出每个水库的碳预算，将评估河流系统的营养状态，并揭示转化陆地和河流碳的生物和物理化学机制之间相互作用的新见解。研究和教学将通过以探究为基础的学生实地项目相结合，解决与更广泛的科学目标相辅相成的离散问题；学生的成绩将被整合到课堂活动中，为其他数百名学生加强科学教育。该项目将为本科地球科学家提供解决复杂环境问题的技能，让他们在学术生涯的早期阶段就进行实地研究。科罗拉多河系统为研究大型管理河流提供了独特的机会，这项工作的结果将为支持当代河流系统碳循环的生物地球化学机制提供见解。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Rivers are the dynamic link between terrestrial and aquatic ecosystems. The biogeochemical processes that produce, consume, and transform organic carbon in rivers are critical to understanding regional carbon budgets, the controls on river water quality, and ultimately the export of terrestrial organic carbon to coastal regions. Our basic understanding of river carbon cycling is based largely on data from pristine rivers; yet today virtually all rivers are managed to optimize water supply, flood control and hydropower. On the Colorado River a system of dams and reservoirs has dramatically altered hydrodynamics and geomorphology, water residence time, particle load, light conditions, and sediment-water interactions. Comparatively little is known about the effects of these reservoirs on carbon biogeochemistry. This project will assess the distribution, composition and reactivity of terrestrial and riverine carbon along a sequence of well-characterized reservoirs in a single watershed. This CAREER project integrates hypothesis-driven biogeochemical research questions, state-of-the-art analytical approaches, and innovative teaching strategies to address three fundamental research elements: 1. Developing a regional carbon budget for the Colorado River System using a combination of field measurements and laboratory manipulation experiments.2. Examining the composition, reactivity, and fate of dissolved and particulate organic carbon in the Colorado River System.3. Enhancing learning outcomes for geoscience students through field-based teaching.Longitudinal water sampling, carbon characterization, and biogeochemical process studies, culminating in a carbon budget for each reservoir, will assess the trophic state of the river system and reveal new insights into the interactions among the biological and physico-chemical mechanisms that transform terrestrial and riverine carbon. The research and teaching will be integrated through inquiry-based student field-projects that address discrete questions complementary to the broader scientific objective; the students results will be integrated into classroom activities, enhancing science education for hundreds of other students. This project will provide undergraduate geoscientists the skills to address complex environmental problems by exposing them to field-based research at an early stage in their academic career. The Colorado river system provides a unique opportunity to study a large managed river, and the results of this work will provide insight for the biogeochemical mechanisms that support carbon cycling in contemporary river systems.