Long, H., Vihermaa, L., Waldron, S. , Hoey, T. , Quemin, S. and Newton, J. (2015) Hydraulics are a first order control on CO2 efflux from fluvial systems. Journal of Geophysical Research: Biogeosciences, 120(10), pp. 1912-1922. (doi: 10.1002/2015JG002955)
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Abstract
Evasion of carbon dioxide (CO2) from fluvial systems is now recognized as a significant component of the global carbon cycle. However the magnitude of, and controls on, this flux remain uncertain and improved understanding of both are required to refine global estimates of fluvial CO2 efflux. CO2 efflux data show no pattern with latitude suggesting that catchment biological productivity is not a primary control and that an alternative explanation for inter-site variability is required. It has been suggested that increased flow velocity and turbulence enhance CO2 efflux, but this is not confirmed. Here, using contemporaneous measurements of efflux (range: 0.07 – 107 µmol CO2 m-2 s-1), flow hydraulics (mean velocity range: 0.03 – 1.39 m s-1) and pCO2 (range: 174 – 10712 µatm) at six sites, we find that flow intensity is a primary control on efflux across two climatically different locations (where pH is not a limiting factor) and that the relationship is refined by incorporating the partial pressure of CO2 (pCO2) of the water. A remaining challenge is how to upscale from point to reach or river basin level. Remote imaging or river surface may be worth exploring if subjectivity in interpreting surface state can be overcome.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Waldron, Professor Susan and Newton, Dr Jason and Vihermaa, Dr Leena and Hoey, Professor Trevor |
| Authors: | Long, H., Vihermaa, L., Waldron, S., Hoey, T., Quemin, S., and Newton, J. |
| College/School: | College of Science and Engineering > School of Geographical and Earth Sciences College of Science and Engineering > Scottish Universities Environmental Research Centre |
| Journal Name: | Journal of Geophysical Research: Biogeosciences |
| Publisher: | American Geophysical Union |
| ISSN: | 2169-8953 |
| ISSN (Online): | 2169-8961 |
| Published Online: | 01 September 2015 |
| Copyright Holders: | Copyright © 2015 The Authors |
| First Published: | First published in Geophysical Research 120(10):1912-1922 |
| Publisher Policy: | Reproduced under a Creative Commons License |
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