Evaluating stream CO2outgassing via drifting and anchored flux chambers in a controlled flume experiment
Résumé
Carbon dioxide (CO2) emissions from running waters represent a key component of the global carbon cycle. However, quantifying CO2 fluxes across air–water boundaries remains challenging due to practical difficulties in the estimation of reach-scale standardized gas exchange velocities (k600) and water equilibrium concentrations. Whereas craft-made floating chambers supplied by internal CO2 sensors represent a promising technique to estimate CO2 fluxes from rivers, the existing literature lacks rigorous comparisons among differently designed chambers and deployment techniques. Moreover, as of now the uncertainty of k600 estimates from chamber data has not been evaluated. Here, these issues were addressed by analysing the results of a flume experiment carried out in the Summer of 2019 in the Lunzer:::Rinnen – Experimental Facility (Austria). During the experiment, 100 runs were performed using two different chamber designs (namely, a standard chamber and a flexible foil chamber with an external floating system and a flexible sealing) and two different deployment modes (drifting and anchored). The runs were performed using various combinations of discharge and channel slope, leading to variable turbulent kinetic energy dissipation rates (1.5×10−3<ε<1×10−1 m2 s−3). Estimates of gas exchange velocities were in line with the existing literature (4
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GéochimieOrigine | Publication financée par une institution |
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https://insu.hal.science/insu-03164753
Soumis le : mercredi 10 mars 2021-10:41:13
Dernière modification le : mardi 21 mai 2024-15:34:17
Archivage à long terme le : vendredi 11 juin 2021-18:30:23
Citer
Filippo Vingiani, Nicola Durighetto, Marcus Klaus, Jakob Schelker, Thierry Labasque, et al.. Evaluating stream CO2outgassing via drifting and anchored flux chambers in a controlled flume experiment. Biogeosciences, 2021, 18 (3), pp.1223-1240. ⟨10.5194/bg-18-1223-2021⟩. ⟨insu-03164753⟩
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