Ocean alkalinity enhancement in an open-ocean ecosystem: biogeochemical responses and carbon storage durability

Paul, Allanah Joy; Haunost, Mathias; Goldenberg, Silvan Urs; Hartmann, Jens; Sánchez, Nicolás; Schneider, Julieta; Suitner, Niels; Riebesell, Ulf

doi:https://doi.org/10.5194/bg-22-2749-2025

Articles | Volume 22, issue 12

https://doi.org/10.5194/bg-22-2749-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Environmental impacts of ocean alkalinity enhancement

https://doi.org/10.5194/bg-22-2749-2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 12

Research article

|

18 Jun 2025

Research article |

| 18 Jun 2025

Ocean alkalinity enhancement in an open-ocean ecosystem: biogeochemical responses and carbon storage durability

Allanah Joy Paul, Mathias Haunost, Silvan Urs Goldenberg, Jens Hartmann, Nicolás Sánchez, Julieta Schneider, Niels Suitner, and Ulf Riebesell

Supplement

https://doi.org/10.5194/bg-22-2749-2025-supplement

Data sets

KOSMOS 2021 Gran Canaria mesocosm study on ocean alkalinity enhancement: water column biogeochemistry and pigments [dataset] Allanah Joy Paul et al. https://doi.org/10.1594/PANGAEA.966941

Ocean Alkalinity Enhancement Incubation Experiments with Particle Seeding (GC2021 KOSMOS experiment) - carbonate chemistry [dataset] Niels Suitner et al. https://doi.org/10.1594/PANGAEA.966991

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Short summary

Ocean alkalinity enhancement (OAE) is being assessed for its potential to absorb atmospheric CO₂ and store it for a long time. OAE still needs comprehensive assessment of its safety and effectiveness. We studied an idealised OAE application in a natural low-nutrient ecosystem over 1 month. Our results showed that biogeochemical functioning remained mostly stable but that the long-term capability for storing carbon may be limited at high alkalinity concentration.