A novel approach to quantify air-water gas exchange in shallow surface waters using high-resolution time series of dissolved atmospheric gases

Weber, Ulrich W., Cook, Peter G., Brennwald, Matthias S., Kipfer, Rolf, and Stieglitz, Thomas C. (2019) A novel approach to quantify air-water gas exchange in shallow surface waters using high-resolution time series of dissolved atmospheric gases. Environmental Science and Technology, 53 (3). pp. 1463-1470.

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View at Publisher Website: https://doi.org/10.1021/acs.est.8b05318
 
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Abstract

Gas exchange across the air-water interface is a key process determining the release of greenhouse gases from surface waters and a fundamental component of gas dynamics in aquatic systems. To experimentally quantify the gas transfer velocity in a wide range of aquatic settings, a novel method based on recently developed techniques for the in situ, near-continuous measurement of dissolved (noble) gases with a field portable mass spectrometer is presented. Variations in observed dissolved gas concentrations are damped and lagged with respect to equilibrium concentrations, being the result of (a) temperature (and thus solubility) variations, (b) water depth, and (c) the specific gas transfer velocity (k(i)). The method fits a model to the measured gas concentrations to derive the gas transfer velocity from the amplitude and the phase lag between observed and equilibrium concentrations. With the current experimental setup, the method is sensitive to gas transfer velocities of 0.05-9 m/day (for N-2), at a water depth of 1 m, and a given daily water temperature variation of 10 degrees C. Experiments were performed (a) in a controlled experiment to prove the concept and to confirm the capability to determine low transfer velocities and (b) in a field study in a shallow coastal lagoon covering a range of transfer velocities, demonstrating the field applicability of the method.

Item ID: 57234
Item Type: Article (Research - C1)
ISSN: 1520-5851
Copyright Information: Copyright © 2018 American Chemical Society
Funders: French National Research Agency (ANR)
Projects and Grants: A/MIDEX ANR-IDEX-0001-02
Date Deposited: 27 Feb 2019 07:31
FoR Codes: 04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology @ 50%
04 EARTH SCIENCES > 0403 Geology > 040305 Marine Geoscience @ 50%
SEO Codes: 96 ENVIRONMENT > 9602 Atmosphere and Weather > 960201 Atmospheric Composition (incl. Greenhouse Gas Inventory) @ 50%
96 ENVIRONMENT > 9611 Physical and Chemical Conditions of Water > 961102 Physical and Chemical Conditions of Water in Coastal and Estuarine Environments @ 50%
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