Climate variability controls on CO2 consumption fluxes and carbon dynamics for monsoonal rivers: evidence from Xijiang River, Southwest China

Zhong, J., Li, S.-L., Liu, J., Ding, H., Sun, X., Xu, S., Wang, T., Ellam, R. M. and Liu, C.-Q. (2018) Climate variability controls on CO2 consumption fluxes and carbon dynamics for monsoonal rivers: evidence from Xijiang River, Southwest China. Journal of Geophysical Research: Biogeosciences, 123(8), pp. 2553-2567. (doi: 10.1029/2018jg004439)

Abstract

The feedbacks of climate variability on CO2 consumption fluxes and carbon dynamics are thought to play an important role in moderating the global carbon cycle. High‐frequency sampling campaigns and analyses were conducted in this study to investigate temporal variations of river water chemistry and the impacts of climate variability on CO2 consumption fluxes and carbon dynamics for the Xijiang River, Southwest China. Physical processes modify biogeochemical processes, so major ions display different responses to changing discharge. The annual CO2 consumption rate is (6.8 ± 0.2) × 106 ton/year by carbonate weathering and (2.4 ± 0.3) × 106 ton/year by silicate weathering. The annual CO2 consumption flux is much higher than most world rivers, and strong CO2 consumption capacities are observed in catchments in Southwest China. Lower negative δ13CDIC values are found in the high‐flow season which corresponds with high temperatures compared to those in the low‐flow season. High discharge will accelerate material transport, and high temperatures will increase primary production in the catchment, both of which can be responsible for the shift of δ13CDIC values in the high‐flow season. Increased mineral weathering and biological carbon influx in the catchment are the main factors controlling carbon dynamics. Overall, these findings highlight the sensitivity of CO2 consumption fluxes and carbon dynamics in response to climate variability in the riverine systems.

• Item Type: Articles
• Additional Information: This work is financially supported by the National Key R & D Program of China through grant 2016YFA0601002 and the National Natural Science Foundation of China (grants 41422303, 41571130072, and 41130536).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ellam, Professor Rob and Xu, Dr Sheng
• Authors: Zhong, J., Li, S.-L., Liu, J., Ding, H., Sun, X., Xu, S., Wang, T., Ellam, R. M., and Liu, C.-Q.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Journal of Geophysical Research: Biogeosciences
• Publisher: American Geophysical Union (AGU)
• ISSN: 2169-8953
• ISSN (Online): 2169-8961
• Published Online: 06 August 2018
• Copyright Holders: Copyright © 2018 American Geophysical Union
• First Published: First published in Journal of Geophysical Research: Biogeosciences 123(8): 2553-2567
• Publisher Policy: Reproduced in accordance with the publisher copyright policy