Modelling of bubble-mediated gas transfer: Fundamental principles and a laboratory test

D. K. Woolf, I. S. Leifer, P. D. Nightingale, T. S. Rhee, P. Bowyer, G. Caulliez, G. de Leeuw, S. E. Larsen, M. Liddicoat, J. Baker, M. O. Andreae

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61 Citations (Scopus)

Abstract

The air–water exchange of gases can be substantially enhanced by wave breaking and specifically by bubble-mediated transfer. A feature of bubble-mediated transfer is the additional pressure on bubbles resulting from the hydrostatic forces on a submerged bubble and from surface tension and curvature. This peculiarity results in asymmetry of bubble-mediated gas transfer and equilibrium supersaturations of dissolved gases in a bubbly ocean. A second peculiarity is the finite capacity of bubbles, so that the composition of a bubble may change during the exchange. The result is that gas transfer mediated by bubbles is characterized by an altered dependence on the molecular properties of the dissolved gas compared to direct transfer across the main air–water interface. A related phenomenon for bubble plumes with a high void fraction (air volume to total volume ratio) is that the composition of the dissolved gas within the interstitial water of a plume may alter during the exchange process and only mix into the full water reservoir later. Three asymptotes are identified for gas exchange mediated by high-void-fraction bubble plumes and a semi-empirical parameterization of bubble-mediated gas transfer is devised on the basis of these asymptotes, which describes the dependence of the overall transfer velocity on plume properties and molecular properties of the gas.
Original languageEnglish
Pages (from-to)71-91
Number of pages21
JournalJournal of Marine Systems
Volume66
Issue number1-4
DOIs
Publication statusPublished - Jun 2007

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