DOI: 10.1029/2018JG004388
Scopus记录号: 2-s2.0-85050386599
论文题名: Gas Transfer Velocities Evaluated Using Carbon Dioxide as a Tracer Show High Streamflow to Be a Major Driver of Total CO2 Evasion Flux for a Headwater Stream
作者: McDowell M.J. ; Johnson M.S.
刊名: Journal of Geophysical Research: Biogeosciences
ISSN: 21698953
出版年: 2018
卷: 123, 期: 7 起始页码: 2183
结束页码: 2197
语种: 英语
英文关键词: biogeochemistry
; carbon cycle
; greenhouse gases
; headwaters
; inland waters
; water-atmosphere exchange
英文摘要: Evasion of carbon dioxide (CO2) from headwater streams is a dominant process controlling the fate of terrestrially derived carbon in inland waters. However, limitations of sampling techniques inhibit efforts to accurately characterize CO2 evasion from streams, and particularly headwater streams with steep gradients, complex morphologies, and challenging terrain. CO2 source dynamics coupled with turbulence conditions control gas transfer velocities of CO2 (kCO2) and therefore drive CO2 evasion. We present estimates of kCO2 and CO2 evasion from a steep, turbulent headwater stream in southwestern British Columbia, Canada, collected using an automated in situ CO2 tracer technique. Gas transfer velocities scaled positively with discharge, with a median kCO2 of 36.8 m/day and a range of 13.5 to 169 m/day. Gas transfer velocities were highest during high-flow events, with 84% of all CO2 emissions occurring when discharge was higher than Q50, the median discharge (92.6 L/s). Widely used models overestimated gas transfer velocities with a mean relative error of 24% but underestimated k600 values above 165 m/day. Our determinations of gas transfer velocities for a range of streamflow suggest that CO2 evasion may be higher than previously estimated from direct measurements or models, particularly during high-flow events. These findings illustrate the need for direct, frequent, in situ determinations of kCO2 to accurately characterize CO2 evasion dynamics in steep headwater streams. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113631
Appears in Collections: 气候减缓与适应
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作者单位: Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, Canada; Institute for Resources, Environment, and Sustainability, University of British Columbia, Vancouver, Canada
Recommended Citation:
McDowell M.J.,Johnson M.S.. Gas Transfer Velocities Evaluated Using Carbon Dioxide as a Tracer Show High Streamflow to Be a Major Driver of Total CO2 Evasion Flux for a Headwater Stream[J]. Journal of Geophysical Research: Biogeosciences,2018-01-01,123(7)