EGU25-20035, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-20035
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Around 40% of riverine DIC export originates from weathering carbon sink in China over the past two decades
Yanzi Yan1,2,3, Xuhui Wang1, Lishan Ran4, Pierre Regnier5, Ronny Lauerwald6, Petter Pilesjö2,7, and Martin Berggren2
Yanzi Yan et al.
  • 1Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China
  • 2Department of Physical Geography and Ecosystem Sciences, Lund University, Lund, Sweden
  • 3Swedish University of Agricultural Sciences, Department of Soil and Environment, Uppsala, Sweden (yanzi.yan@slu.se)
  • 4Department of Geography, The University of Hong Kong, Pok Fu Lam Road, Hong Kong.
  • 5Department Geoscience, Environment & Society- BGEOSYS, Université Libre de Bruxelles, 1050, Bruxelles, Belgium
  • 6Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 78850, Thiverval-Grignon, France
  • 7Lund University GIS Center, Lund, Sweden

Dissolved inorganic carbon (DIC) transport along the land-ocean continuum, accounts for ~50% of the lateral carbon fluxes at global scale. One major source of riverine DIC comes from atmospheric carbon dioxide (CO2) uptake by chemical weathering process, which has currently been recognized as a potentially significant contributor of climate mitigation in addition to photosynthesis. However, we still have no clue how much this inorganic carbon sink would end up in the riverine DIC at regional scale and how/whether riverine DIC export has changed over space and time. China with a vast karst area (~1.9 million km2) and higher riverine DIC concentration than the global averaged value (~10mg/L), is particularly one of the largest regions with the big knowledge gap just mentioned. In this study, we compiled a large database of in situ riverine DIC observations (1895 records at 684 observations) in China  based on which a machine-learning approach was used to estimate the riverine DIC concentrations (CDIC) and fluxes (FDIC), and evaluate the contribution of chemical weathering to riverine DIC fluxes. Results show that over the period 2001-2018, CDIC in China was on average 22.53 ± 6.62 mg/L with a significant decrease of -0.036 mg C/L/yr (P=0.01) and FDIC was 38.33 ± 9.39 Tg C/yr with little change (0.418 Tg C/yR2, P>0.05). In addition, chemical weathering carbon sink was found to account for ~40% of averaged FDIC at country scale while it can amount up to ~60% of FDIC in the southwest of China. Changes in pH and hydrologic conditions were found to dominate the FDIC across China regardless of whether the basin is chemical weathering dominated or not. GPP, land cover change and soil temperature are also found to contribute substantially to the FDIC in the south of China compared to the north of China.

How to cite: Yan, Y., Wang, X., Ran, L., Regnier, P., Lauerwald, R., Pilesjö, P., and Berggren, M.: Around 40% of riverine DIC export originates from weathering carbon sink in China over the past two decades, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20035, https://doi.org/10.5194/egusphere-egu25-20035, 2025.