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Sensitivity of chemical weathering and dissolved carbon dynamics to hydrological conditions in a typical karst river

To better understand the mechanisms that hydrological conditions control chemical weathering and carbon dynamics in the large rivers, we investigated hydrochemistry and carbon isotopic compositions of dissolved inorganic carbon (DIC) based on high-frequency sampling in the Wujiang River draining the...

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Detalles Bibliográficos
Autores principales: Zhong, Jun, Li, Si-liang, Tao, Faxiang, Yue, Fujun, Liu, Cong-Qiang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5318914/
https://www.ncbi.nlm.nih.gov/pubmed/28220859
http://dx.doi.org/10.1038/srep42944
Descripción
Sumario:To better understand the mechanisms that hydrological conditions control chemical weathering and carbon dynamics in the large rivers, we investigated hydrochemistry and carbon isotopic compositions of dissolved inorganic carbon (DIC) based on high-frequency sampling in the Wujiang River draining the carbonate area in southwestern China. Concentrations of major dissolved solute do not strictly follow the dilution process with increasing discharge, and biogeochemical processes lead to variability in the concentration-discharge relationships. Temporal variations of dissolved solutes are closely related to weathering characteristics and hydrological conditions in the rainy seasons. The concentrations of dissolved carbon and the carbon isotopic compositions vary with discharge changes, suggesting that hydrological conditions and biogeochemical processes control dissolved carbon dynamics. Biological CO(2) discharge and intense carbonate weathering by soil CO(2) should be responsible for the carbon variability under various hydrological conditions during the high-flow season. The concentration of DIC(bio) (DIC from biological sources) derived from a mixing model increases with increasing discharge, indicating that DIC(bio) influx is the main driver of the chemostatic behaviors of riverine DIC in this typical karst river. The study highlights the sensitivity of chemical weathering and carbon dynamics to hydrological conditions in the riverine system.