Carbon fluxes in the coastal ocean: Synthesis, boundary processes and future trends
The sustained coastal and open ocean carbon sink is vital in mitigating climate change and meeting the target set by the Paris Agreement. This review examines the current understanding of the global coastal ocean carbon cycle and provides a new quantitative synthesis of air-sea CO₂ exchange. This reanalysis yields an estimate for the globally integrated coastal ocean CO₂ flux of −0.25 ± 0.05 Pg C year-1. A framework that classifies river-dominated ocean margin (RiOMar) and ocean-dominated margin (OceMar) systems is used to conceptualize coastal carbon cycle processes. Ocean carbon models that range from box models to three-dimensional coupled circulation-biogeochemical models are reviewed in terms of the ability to simulate key processes and project future changes in different continental shelf regions. Knowledge gaps in projecting future perturbations associated with before and after net-zero CO₂ emissions in the context of concurrent changes in the land-ocean-atmosphere coupled system pose a key challenge.
Reference: Dai, M., Su, J., Zhao, Y., et al., (2022). Carbon fluxes in the coastal ocean: Synthesis, boundary processes and future trends. Annual Review of Earth and Planetary Sciences, 50, https://doi.org/10.1146/annurev-earth-032320-090746.