Unraveling the Contribution of Turbulence and Bubbles to Air-Water Gas Exchange in Running Waters.

ABSTRACT: Quantifying air-water gas exchange is critical for estimating greenhouse gas fluxes and metabolism in aquatic ecosystems. In high-energy streams, the gas exchange rate k is poorly constrained, due to an incomplete understanding of turbulence and bubble contributions to k. We performed a flume experiment with air bubble additions to evaluate the combined effects of turbulence and bubbles on k for helium, argon, xenon, and methane. We created contrasting hydraulic conditions by varying channel slope, bed roughness, water discharge, and bubble flux. We found that k increased from 1-4 to 17-66 m d^-1 with increases in turbulence and bubble flux metrics. Mechanistic models that explicitly account for these metrics, as well as gas diffusivity and solubility,

SUBMITTER: Klaus M 

PROVIDER: S-EPMC9285787 | biostudies-literature | 2022 Mar

REPOSITORIES: biostudies-literature