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 the role rivers play in regional carbon budgets, the controls on river water quality, and ultimately riverine export of terrestrial organic carbon to coastal regions. Our basic understanding of river carbon cycling is based on data from relatively pristine rivers; yet today, virtually all large rivers are managed to optimize water supply, flood control and hydropower. Biogeochemical processes in reservoirs affect terrestrial and riverine carbon differently. However, the implications of differential storage and export of these two pools for regional carbon budgets are not well known. Neither is much known about the effects of changing climate on riverine storage and/or export of terrestrial carbon. Colorado River reclamation projects supply drinking water to much of the Southwestern US and the dams have dramatically altered river hydrodynamics and geomorphology. The series of reservoirs on the Colorado R. vary in size, climate, land-use, and human perturbation; this makes the Colorado an ideal system in which to assess the distribution, composition and reactivity of terrestrial and riverine carbon among well characterized reservoirs in a single watershed. Intellectual Merit: The proposed work integrates hypothesis-driven research questions, stateof- the-art analytical capabilities (electrospray ionization-mass spectrometry), and inquiry-based teaching strategies to address three objectives: 1. Developing a regional carbon budget for the Colorado River System. 2. Examining composition and reactivity DOC and POC in the Colorado River System. 3. Enhancing learning outcomes for geoscience students through field-based teaching. Longitudinal water sampling, carbon characterization measurements 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. This is a unique opportunity to study carbon cycling in a large managed river. Research and teaching will be integrated through inquiry-based student projects complementary to the larger research objectives. The field-research and field-teaching are critical to providing students with the context and intuition necessary to understand complex environmental questions. These techniques represent some of the latest best-practices for learner-centered education. Broader Impacts: High-level integration of teaching and research is the core of this project. Graduate and undergraduate students will gain transdisciplinary research experience through field-based projects, biogeochemical experiments, instrumental analyses, data interpretation, and the presentation and publication of their results. In addition, the project develops a partnership between the PI and scientists from the National Park Service and the USGS, providing not only a collaborative experience for the students but also new biogeochemical process data that the NPS and USGS can leverage both for management and public outreach. The PI actively promotes field-research experiences to women and minority students through the NSF-funded Minority Graduate Education at Mountain State Alliance (MGE@MSA) at ASU. This CAREER project will lay the groundwork for establishing a Southwestern Riverine Research Center at Arizona State University (ASU). These elements address four categories of the NSF broader impacts criteria: enhancing infrastructure, broadening the participation of underrepresented groups, promoting training and learning, and broad dissemination of results.
|Effective start/end date||9/1/09 → 8/31/14|
- National Science Foundation (NSF): $573,548.00