Anomalous summertime CO<sub>2</sub> sink in the subpolar Southern Ocean promoted by early 2021 sea ice retreat

Naëck, Kirtana; Boutin, Jacqueline; Swart, Sebastiaan; du Plessis, Marcel; Merlivat, Liliane; Beaumont, Laurence; Lourenco, Antonio; d'Ovidio, Francesco; Rousselet, Louise; Ward, Brian; Sallée, Jean-Baptiste

doi:https://doi.org/10.5194/bg-22-1947-2025

Articles | Volume 22, issue 8

https://doi.org/10.5194/bg-22-1947-2025

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

https://doi.org/10.5194/bg-22-1947-2025

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

Articles | Volume 22, issue 8

Research article

|

23 Apr 2025

Research article |

| 23 Apr 2025

Anomalous summertime CO₂ sink in the subpolar Southern Ocean promoted by early 2021 sea ice retreat

Kirtana Naëck, Jacqueline Boutin, Sebastiaan Swart, Marcel du Plessis, Liliane Merlivat, Laurence Beaumont, Antonio Lourenco, Francesco d'Ovidio, Louise Rousselet, Brian Ward, and Jean-Baptiste Sallée

Supplement

https://doi.org/10.5194/bg-22-1947-2025-supplement

Data sets

CARIOCA observations - SO-CHIC Cruise 2022 Kirtana Naëck et al. https://doi.org/10.17882/100800

Dataset from autonomous assets collected during the SO-CHIC field campaign in the Southern Ocean S. Swart et al. https://doi.org/10.5281/zenodo.11059426

TSG observations – SO-CHIC Cruise 2022 B. Ward et al. https://doi.org/10.17882/100905

CTD observation - SO-CHIC Cruise 2022 Nadine Steiger et al. https://doi.org/10.17882/95314

ERA5 hourly data on single levels from 1940 to present H. Hersbach et al. https://doi.org/10.24381/cds.adbb2d47

SMOS SSS L3 maps generated by CATDS CEC LOCEAN. debias V8.0 J. Boutin et al. https://doi.org/10.17882/52804#102161

CORA, Coriolis Ocean Dataset for Reanalysis T. Szekely et al. https://doi.org/10.17882/46219

OSCAR third deg. Ver. 1 ESR https://doi.org/10.5067/OSCAR-03D01

Global Sea Ice Concentration Climate Data Record v3.0 - Multimission OSI SAF https://doi.org/10.15770/EUM_SAF_OSI_0013

Global Sea Ice Concentration Interim Climate Data Record Release 3 - DMSP OSI SAF https://doi.org/10.15770/EUM_SAF_OSI_0014

Global Ocean Physics Reanalysis E.U. Copernicus Marine Service Information (CMEMS) and Marine Data Store (MDS) https://doi.org/10.48670/moi-00021

Global Ocean Physics Analysis and Forecast E.U. Copernicus Marine Service Information (CMEMS) and Marine Data Store (MDS) https://doi.org/10.48670/moi-00016

Global Total (COPERNICUS-GLOBCURRENT), Ekman and Geostrophic currents at the Surface and 15m E.U. Copernicus Marine Service Information (CMEMS) and Marine Data Store (MDS) https://doi.org/10.48670/mds-00327

ESA Ocean Colour Climate Change Initiative (Ocean_Colour_cci): Monthly climatology of global ocean colour data products at 4km resolution S. Sathyendranath et al. https://catalogue.ceda.ac.uk/uuid/690fdf8f229c4d04a2aa68de67beb733/

Model code and software

SPASSO OceanCruises https://github.com/OceanCruises/SPASSO/

Video abstract

Anomalous summertime CO2 sink in the subpolar Southern Ocean promoted by early 2021 sea ice retreat Kirtana Naëck https://doi.org/10.5446/69858

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Short summary

In summer 2022, a CARbon Interface OCean Atmosphere (CARIOCA) drifting buoy observed an anomalously strong ocean carbon sink in the subpolar Southern Ocean associated with large plumes of chlorophyll a. Lagrangian backward trajectories indicate that these waters originated from the sea ice edge in spring 2021. Our study highlights the northward migration of the CO₂ sink associated with early sea ice retreat.