EAGER research: Gas exchange over the air-water interface of freshwater systems

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

This EAGER project (EArly-concept Grant for Exploratory Research) explores a new way to more accurately measure the exchange of oxygen, carbon dioxide and methane between the water and the air above streams, lakes and rivers. This is a critically important process in ecosystems, yet current measurement approaches are difficult to employ and all have substantial weaknesses. If proven, this new approach would fundamentally change our understanding of gas exchange processes for aquatic ecosystems. Project findings will be disseminated through web site development, sessions and workshops at international meetings, and scientific papers. Undergraduate and graduate students will be trained in high frequency data acquisition with complex instruments and analysis of big data produced in this project. The new procedures will be tested and evaluated at field sites that have been the focus of considerable other support related to the prediction of tipping points in aquatic ecosystems; if this new approach works, these other studies will immediately benefit. A new dual oxygen-temperature sensor will enable two parallel independent estimates for the exchange coefficient, one based on the oxygen flux and one on the heat flux. The core novel idea is to apply this tested approach upside down right below the air-water interface and from measured vertical gas fluxes and concentrations below and above the interface, calculate the much sought after gas exchange coefficient. Measurements will be performed from two platforms, a stationary one for shallow rivers and streams with unidirectional flow, and a small radio-controlled moving surface vessel for reservoirs and lakes without consistent well-defined current flows.