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Article: Dynamic biogeochemical controls on river pCO2 and recent changes under aggravating river impoundment: An example of the subtropical Yangtze River

TitleDynamic biogeochemical controls on river pCO<inf>2</inf> and recent changes under aggravating river impoundment: An example of the subtropical Yangtze River
Authors
Keywordsautotrophy
Issue Date2016
Citation
Global Biogeochemical Cycles, 2016, v. 30, n. 6, p. 880-897 How to Cite?
Abstract©2016. American Geophysical Union. All Rights Reserved.This paper highlights two aspects of the dynamic biogeochemical controls of riverine pCO2 in an increasingly impounded large subtropical river (the Yangtze): the terrestrial dominance through internal respiration of land-derived organic carbon and the influence of increased autotrophic activity in impounded areas on river pCO2. River pCO2 and total organic carbon (TOC) increase downstream on the main stem (pCO2: 528–1703 µatm; TOC: 137–263 µmol/L) and vary significantly among tributaries (464–3300 µatm; TOC: 109–340 µmol/L). pCO2 displays larger spatial variability than temporal variability and is spatially correlated with river organic carbon across the river (p < 0.05–0.0001, seasonally independent). pCO2 is also negatively correlated with dissolved oxygen (r2 = 0.46, p < 0.0001). Respiration of allochthonous organic carbon in water column is concluded as an essential source of CO2 supersaturation and river heterotrophy. However, significant benthic respiration and/or direct soil CO2 transport (e.g., via groundwater, ~80%) exist at the same time. The temporal and spatial distribution of POC compositional characteristics and chlorophyll a indicate the dominant control of terrestrial processes (e.g., organic matter transport and soil erosion) on the river pCO2 biogeochemistry, especially in warm seasons. Increased autotrophy and significant pCO2 decrease (>60%) do occur in impounded areas (especially in nutrient-rich rivers), but the decrease is mostly temporal and regional (~8% of the data points are significantly influenced, all from the upper reach and/or major tributaries). The paper concludes that terrestrial influence still dominates the pCO2 biogeochemistry in this increasingly intercepted and regulated river system.
Persistent Identifierhttp://hdl.handle.net/10722/228254
ISSN
2015 Impact Factor: 4.495
2015 SCImago Journal Rankings: 3.220

 

DC FieldValueLanguage
dc.contributor.authorLiu, Shaoda-
dc.contributor.authorLu, Xi Xi-
dc.contributor.authorXia, Xinghui-
dc.contributor.authorZhang, Shurong-
dc.contributor.authorRan, Lishan-
dc.contributor.authorYang, Xiankun-
dc.contributor.authorLiu, Ting-
dc.date.accessioned2016-08-01T06:45:34Z-
dc.date.available2016-08-01T06:45:34Z-
dc.date.issued2016-
dc.identifier.citationGlobal Biogeochemical Cycles, 2016, v. 30, n. 6, p. 880-897-
dc.identifier.issn0886-6236-
dc.identifier.urihttp://hdl.handle.net/10722/228254-
dc.description.abstract©2016. American Geophysical Union. All Rights Reserved.This paper highlights two aspects of the dynamic biogeochemical controls of riverine pCO2 in an increasingly impounded large subtropical river (the Yangtze): the terrestrial dominance through internal respiration of land-derived organic carbon and the influence of increased autotrophic activity in impounded areas on river pCO2. River pCO2 and total organic carbon (TOC) increase downstream on the main stem (pCO2: 528–1703 µatm; TOC: 137–263 µmol/L) and vary significantly among tributaries (464–3300 µatm; TOC: 109–340 µmol/L). pCO2 displays larger spatial variability than temporal variability and is spatially correlated with river organic carbon across the river (p < 0.05–0.0001, seasonally independent). pCO2 is also negatively correlated with dissolved oxygen (r2 = 0.46, p < 0.0001). Respiration of allochthonous organic carbon in water column is concluded as an essential source of CO2 supersaturation and river heterotrophy. However, significant benthic respiration and/or direct soil CO2 transport (e.g., via groundwater, ~80%) exist at the same time. The temporal and spatial distribution of POC compositional characteristics and chlorophyll a indicate the dominant control of terrestrial processes (e.g., organic matter transport and soil erosion) on the river pCO2 biogeochemistry, especially in warm seasons. Increased autotrophy and significant pCO2 decrease (>60%) do occur in impounded areas (especially in nutrient-rich rivers), but the decrease is mostly temporal and regional (~8% of the data points are significantly influenced, all from the upper reach and/or major tributaries). The paper concludes that terrestrial influence still dominates the pCO2 biogeochemistry in this increasingly intercepted and regulated river system.-
dc.languageeng-
dc.relation.ispartofGlobal Biogeochemical Cycles-
dc.subjectautotrophy-
dc.titleDynamic biogeochemical controls on river pCO<inf>2</inf> and recent changes under aggravating river impoundment: An example of the subtropical Yangtze River-
dc.typeArticle-
dc.description.natureLink_to_subscribed_fulltext-
dc.identifier.doi10.1002/2016GB005388-
dc.identifier.scopuseid_2-s2.0-84977499554-
dc.identifier.volume30-
dc.identifier.issue6-
dc.identifier.spage880-
dc.identifier.epage897-
dc.identifier.eissn1944-9224-

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