Combining Signals of Dissolved Oxygen and Carbon Dioxide to Infer Whole-stream Metabolism

Abigail Northrup, Dr. Robert Payn, and Meryl Storb, Department of Land Resources and Environmental Science, Montana State University, 334 Leon Johnson Hall P.O. Box 173120, Bozeman MT 59717-3120

Stream metabolism measurements are fundamental indicators of the connection between water quality and watershed processes because they define the foundation of carbon movement through the aquatic ecosystem. Data sets utilizing these measurements can reflect the results of land management decisions, and thus provide a useful tool to monitor the integrity of aquatic ecosystems under the pressures of climate change, land use change, and anthropogenic nutrient loading. Stream metabolism has conventionally been estimated from dissolved oxygen data, but the recent development of reliable automated dissolved carbon dioxide sensors may provide another window into stream metabolic processes. We are designing and testing software to infer whole-stream metabolic rates (gross primary production and ecosystem respiration) based on high-frequency measurements of both dissolved oxygen and carbon dioxide. Inferences from initial models and data sets suggest that dissolved oxygen and carbon dioxide do not result in similar inferred estimates for gross primary production (GPP) and ecosystem respiration (ER). This research tests different modeling scenarios to suggest the most likely reasons for this discrepancy. For example, our top priority is to understand how the assumed photosynthetic quotient (the relative effect of GPP on oxygen vs. carbon dioxide) may influence the inference of metabolism from oxygen and carbon dioxide together. We expect that results from this research will contribute to the ability to extract additional information about whole-stream metabolic measurements via the technological advances in measuring additional dissolved metabolite gasses.

Additional Abstract Information

Presenter: Abigail Northrup

Institution: Montana State University Bozeman

Type: Poster

Subject: Environmental Science & Sustainability

Status: Approved

Time and Location

Session: Poster 6
Date/Time: Tue 2:00pm-3:00pm
Session Number: 4647