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Article: Riverine export of water, sediment and carbon during flood events in the arid to semi‐arid Wuding River on the Chinese Loess Plateau

TitleRiverine export of water, sediment and carbon during flood events in the arid to semi‐arid Wuding River on the Chinese Loess Plateau
Authors
Keywordswater and sediment
carbon export
CO2 degassing
floods
Wuding River catchment
Issue Date2020
PublisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/2388
Citation
Earth Surface Processes and Landforms, 2020, v. 45 n. 8, p. 1777-1788 How to Cite?
AbstractFloods have become increasingly important in fluvial export of water, sediment and carbon (C). Using high‐frequency sampling, the export of water, sediment and C was examined in the Wuding River catchment on the Chinese Loess Plateau. With groundwater as an important contributor to runoff all year round, floods were relatively less important in the export of water. However, large floods were disproportionately important in exporting sediment and inorganic C (DIC) and organic C (DOC and POC). The three largest floods in each year transported 53.6–97.3 and 41.4–77% of the annual sediment and C fluxes, respectively. An extreme flood in 2017 alone contributed 94.6 and 73.1% of the annual sediment and C fluxes, respectively, in just 7 days, which included 20.3, 92.1 and 35.7% of the annual DOC, POC and DIC fluxes, respectively. A stable carbon isotope (δ13C) analysis of POC indicated that modern soils and C3 plants were its primary source. Furthermore, floods greatly accelerated CO2 degassing due to elevated gas transfer velocity, although stream water CO2 partial pressure (pCO2) exhibited a decreasing trend with flow discharge. Although these results illustrated that increasing runoff diluted pCO2, the timing and magnitude of floods were found to be critical in determining the response of pCO2 to flow dynamics. Low‐magnitude floods in the early wet season increased pCO2 because of enhanced organic matter input, while subsequent large floods caused a lower pCO2 due to greatly reduced organic matter supply. Finally, continuous monitoring of a complete flood event showed that the CO2 efflux during the flood (2348 ± 664 mg C m–2 day–1) was three times that under low‐flow conditions (808 ± 98 mg C m–2 day–1). Our study suggests that infrequent, heavy storm events, which are predicted to increase under climate change, will greatly alter the transport regimes of sediment and C. © 2020 John Wiley & Sons, Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/294177
ISSN
2020 Impact Factor: 4.133
2015 SCImago Journal Rankings: 1.574
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorRan, L-
dc.contributor.authorYang, X-
dc.contributor.authorTian, M-
dc.contributor.authorShi, H-
dc.contributor.authorLiu, S-
dc.contributor.authorYu, R-
dc.contributor.authorZhou, Y-
dc.date.accessioned2020-11-23T08:27:28Z-
dc.date.available2020-11-23T08:27:28Z-
dc.date.issued2020-
dc.identifier.citationEarth Surface Processes and Landforms, 2020, v. 45 n. 8, p. 1777-1788-
dc.identifier.issn0197-9337-
dc.identifier.urihttp://hdl.handle.net/10722/294177-
dc.description.abstractFloods have become increasingly important in fluvial export of water, sediment and carbon (C). Using high‐frequency sampling, the export of water, sediment and C was examined in the Wuding River catchment on the Chinese Loess Plateau. With groundwater as an important contributor to runoff all year round, floods were relatively less important in the export of water. However, large floods were disproportionately important in exporting sediment and inorganic C (DIC) and organic C (DOC and POC). The three largest floods in each year transported 53.6–97.3 and 41.4–77% of the annual sediment and C fluxes, respectively. An extreme flood in 2017 alone contributed 94.6 and 73.1% of the annual sediment and C fluxes, respectively, in just 7 days, which included 20.3, 92.1 and 35.7% of the annual DOC, POC and DIC fluxes, respectively. A stable carbon isotope (δ13C) analysis of POC indicated that modern soils and C3 plants were its primary source. Furthermore, floods greatly accelerated CO2 degassing due to elevated gas transfer velocity, although stream water CO2 partial pressure (pCO2) exhibited a decreasing trend with flow discharge. Although these results illustrated that increasing runoff diluted pCO2, the timing and magnitude of floods were found to be critical in determining the response of pCO2 to flow dynamics. Low‐magnitude floods in the early wet season increased pCO2 because of enhanced organic matter input, while subsequent large floods caused a lower pCO2 due to greatly reduced organic matter supply. Finally, continuous monitoring of a complete flood event showed that the CO2 efflux during the flood (2348 ± 664 mg C m–2 day–1) was three times that under low‐flow conditions (808 ± 98 mg C m–2 day–1). Our study suggests that infrequent, heavy storm events, which are predicted to increase under climate change, will greatly alter the transport regimes of sediment and C. © 2020 John Wiley & Sons, Ltd.-
dc.languageeng-
dc.publisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www3.interscience.wiley.com/cgi-bin/jhome/2388-
dc.relation.ispartofEarth Surface Processes and Landforms-
dc.rightsPreprint This is the pre-peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Postprint This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.-
dc.subjectwater and sediment-
dc.subjectcarbon export-
dc.subjectCO2 degassing-
dc.subjectfloods-
dc.subjectWuding River catchment-
dc.titleRiverine export of water, sediment and carbon during flood events in the arid to semi‐arid Wuding River on the Chinese Loess Plateau-
dc.typeArticle-
dc.identifier.emailRan, L: lsran@hku.hk-
dc.identifier.authorityRan, L=rp02173-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1002/esp.4845-
dc.identifier.scopuseid_2-s2.0-85080960704-
dc.identifier.hkuros319301-
dc.identifier.volume45-
dc.identifier.issue8-
dc.identifier.spage1777-
dc.identifier.epage1788-
dc.identifier.isiWOS:000540134800007-
dc.publisher.placeUnited Kingdom-
dc.identifier.issnl0197-9337-

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