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Title: Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux

Abstract

Quantification of soil gas flux using the static chamber method is labor intensive. The number of chambers that can be sampled is limited by the spacing between chambers and the availability of trained research technicians. An automated system for collecting gas samples from chambers in the field would eliminate the need for personnel to return to the chamber during a flux measurement period and would allow a single technician to sample multiple chambers simultaneously. This study describes Chamber Automated Sampling Equipment (FluxCASE) to collect and store chamber headspace gas samples at assigned time points for the measurement of soil gas flux. The FluxCASE design and operation is described, and the accuracy and precision of the FluxCASE system is evaluated. In laboratory measurements of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) concentrations of a standardized gas mixture, coefficients of variation associated with automated and manual sample collection were comparable, indicating no loss of precision. In the field, soil gas fluxes measured from FluxCASEs were in agreement with manual sampling for both N2O and CO2. Slopes of regression equations were 1.01 for CO2 and 0.97 for N2O. The 95% confidence limits of the slopes of the regression lines included themore » value of one, indicating no bias. Additionally, an expense analysis found a cost recovery ranging from 0.6 to 2.2 yr. Implementing the FluxCASE system is an alternative to improve the efficiency of the static chamber method for measuring soil gas flux while maintaining the accuracy and precision of manual sampling.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1427898
Report Number(s):
PNNL-SA-132338
Journal ID: ISSN 0047-2425; 453060036
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Environmental Quality; Journal Volume: 47; Journal Issue: 2
Country of Publication:
United States
Language:
English

Citation Formats

Davis, Morgan P., Groh, Tyler A., Parkin, Timothy B., Williams, Ryan J., Isenhart, Thomas M., and Hofmockel, Kirsten S. Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux. United States: N. p., 2018. Web. doi:10.2134/jeq2017.10.0387.
Davis, Morgan P., Groh, Tyler A., Parkin, Timothy B., Williams, Ryan J., Isenhart, Thomas M., & Hofmockel, Kirsten S. Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux. United States. doi:10.2134/jeq2017.10.0387.
Davis, Morgan P., Groh, Tyler A., Parkin, Timothy B., Williams, Ryan J., Isenhart, Thomas M., and Hofmockel, Kirsten S. Mon . "Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux". United States. doi:10.2134/jeq2017.10.0387.
@article{osti_1427898,
title = {Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux},
author = {Davis, Morgan P. and Groh, Tyler A. and Parkin, Timothy B. and Williams, Ryan J. and Isenhart, Thomas M. and Hofmockel, Kirsten S.},
abstractNote = {Quantification of soil gas flux using the static chamber method is labor intensive. The number of chambers that can be sampled is limited by the spacing between chambers and the availability of trained research technicians. An automated system for collecting gas samples from chambers in the field would eliminate the need for personnel to return to the chamber during a flux measurement period and would allow a single technician to sample multiple chambers simultaneously. This study describes Chamber Automated Sampling Equipment (FluxCASE) to collect and store chamber headspace gas samples at assigned time points for the measurement of soil gas flux. The FluxCASE design and operation is described, and the accuracy and precision of the FluxCASE system is evaluated. In laboratory measurements of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) concentrations of a standardized gas mixture, coefficients of variation associated with automated and manual sample collection were comparable, indicating no loss of precision. In the field, soil gas fluxes measured from FluxCASEs were in agreement with manual sampling for both N2O and CO2. Slopes of regression equations were 1.01 for CO2 and 0.97 for N2O. The 95% confidence limits of the slopes of the regression lines included the value of one, indicating no bias. Additionally, an expense analysis found a cost recovery ranging from 0.6 to 2.2 yr. Implementing the FluxCASE system is an alternative to improve the efficiency of the static chamber method for measuring soil gas flux while maintaining the accuracy and precision of manual sampling.},
doi = {10.2134/jeq2017.10.0387},
journal = {Journal of Environmental Quality},
number = 2,
volume = 47,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2018},
month = {Mon Jan 01 00:00:00 EST 2018}
}