Berger et al. (2023): Ocean dynamics and biological feedbacks limit the potential of macroalgae carbon dioxide removal

Manon Berger, Lester Kwiatkowski, David T Ho, Laurent Bopp IN: Environ. Res. Lett. 18 024039, DOI 10.1088/1748-9326/acb06e

The authors modify a high-resolution ocean biogeochemical model to simulate the consumption of dissolved inorganic carbon and macronutrients by idealised macroalgal cultivation in Exclusive Economic Zones. Under imposed macroalgal production of 0.5 PgC yr⁻¹ with no nutrient feedbacks, physicochemical processes are found to limit the enhancement in the ocean carbon sink to 0.39 PgC yr⁻¹ (1.43 GtCO₂ yr⁻¹), corresponding to CDR efficiency of 79%. Only 0.22 PgC yr⁻¹ (56%) of this air–sea carbon flux occurs in the regions of macroalgae cultivation, posing potential issues for measurement, reporting, and verification.

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