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An Automated Gas Exchange Tank for Determining Gas Transfer Velocities in Natural Seawater Samples : Volume 11, Issue 1 (21/02/2014)

By Schneider-zapp, K.

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Book Id: WPLBN0004020841
Format Type: PDF Article :
File Size: Pages 41
Reproduction Date: 2015

Title: An Automated Gas Exchange Tank for Determining Gas Transfer Velocities in Natural Seawater Samples : Volume 11, Issue 1 (21/02/2014)  
Author: Schneider-zapp, K.
Volume: Vol. 11, Issue 1
Language: English
Subject: Science, Ocean, Science
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Historic
Publication Date:
2014
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

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Salter, M. E., Upstill-Goddard, R. C., & Schneider-Zapp, K. (2014). An Automated Gas Exchange Tank for Determining Gas Transfer Velocities in Natural Seawater Samples : Volume 11, Issue 1 (21/02/2014). Retrieved from http://worldlibrary.net/


Description
Description: Ocean Research Group, School of Marine Science and Technology, Newcastle University, Newcastle upon Tyne, UK. In order to advance understanding of the role of seawater surfactants in the air–sea exchange of climatically active trace gases via suppression of the gas transfer velocity (kw), we constructed a fully automated, closed air-water gas exchange tank and coupled analytical system. The system allows water-side turbulence in the tank to be precisely controlled with an electronically operated baffle. Two coupled gas chromatographs and an integral equilibrator, connected to the tank in a continuous gas-tight system, allow temporal changes in the partial pressures of SF6, CH4 and N2O to be measured simultaneously in the tank water and headspace at multiple turbulence settings, during a typical experimental run of 3.25 h. PC software developed by the authors controls all operations and data acquisition, enabling the optimisation of experimental conditions with high reproducibility. The use of three gases allows three independent estimates of kw for each turbulence setting; these values are subsequently normalised to a constant Schmidt number for direct comparison. The normalised kw estimates show close agreement. Repeated experiments with MilliQ water demonstrate a typical measurement accuracy of 4% for kw. Experiments with natural seawater show that the system clearly resolves the effects on kw of spatial and temporal trends in natural surfactant activity. The system is an effective tool with which to probe the relationships between kw, surfactant activity and biogeochemical indices of primary productivity, and should assist in providing valuable new insights into the air–sea gas exchange process.

Summary
An automated gas exchange tank for determining gas transfer velocities in natural seawater samples

Excerpt
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