A Dimensionless Framework for the Partitioning of Fluvial Inorganic Carbon

Abstract

Rivers are pivotal in the global carbon cycle, transporting terrestrial carbon to the ocean while emitting significant amount of CO2 to the atmosphere. However, the partitioning of fluvial inorganic carbon (IC) between downstream transport and atmospheric evasion remains uncertain due to intricate hydrodynamic and biogeochemical processes. Inspired by Budyko's hydrological work, this study introduces a dimensionless framework to identify critical factors in fluvial IC partitioning: the IC fraction in equilibrium with the atmosphere and the ratio of advection to evasion timescales. River catchment analyses and modeling reveal that the equilibrium ratio determines the fraction of IC stably transported downstream. The hydrodynamic-driven timescale ratio determines the fate of out-of-equilibrium IC, with low-order streams favoring atmospheric evasion and higher-order streams promoting downstream transport. This framework provides a simple yet robust approach to predicting river carbon dynamics, with implications for land-to-ocean transport, fluvial emissions, and climate mitigation strategies such as enhanced weathering.

Keywords

carbon; rivers; CO2 emissions; water chemistry; turbulence

Published in

Geophysical Research Letters
2024, volume: 51, number: 19, article number: e2024GL111310
Publisher: AMER GEOPHYSICAL UNION

SLU Authors

• Yan, Yanzi

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Geosciences, Multidisciplinary

Publication identifier

• DOI: https://doi.org/10.1029/2024GL111310

Permanent link to this page (URI)

https://res.slu.se/id/publ/140150