Collaborative Research: Plumbing watershed CO2 evasion

Streams and rivers are natural sources of CO2 to the atmosphere. Many rivers have higher concentrations of CO2 than the atmosphere, which creates a movement of CO2 from the river to the air. Wetlands and floodplains can contribute large amounts of this greenhouse gas to rivers and streams when they are connected by overland flooding. The goal of this project is to determine what types of wetlands and floodplains add the most CO2 to adjacent streams and rivers and under what conditions. The proposed work includes a combination of modeling and field measurements. We will begin by modeling how much (magnitude), how often (frequency), and for how long (duration) rivers are exchanging water with wetland/floodplains in the Connecticut River watershed. We will use this information to pick several wetlands and floodplains with variability in magnitude, frequency, and duration for field measurements. During the field campaign, we will use a combination of continuous instruments and water samples to determine how much CO2 is moving from the wetlands and floodplains to rivers. We will then build a computer model that captures these field measurements to estimate these exchanges for the entire watershed. Using this model, we will then test the overall importance of magnitude, frequency, and duration of flooding to CO2 concentrations and emissions from streams and rivers of different sizes and during different seasons. This work will improve understanding of the contribution of aquatic habitats and their connectivity to greenhouse gas emissions. 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.