What the study found
The study found that Southern Ocean net primary production is about 6.5 ± 1.36 PgC yr−1, which is higher than most CMIP6 model and satellite-based estimates but consistent with Argo oxygen-based estimates.
Why the authors say this matters
The authors say these productivity estimates provide quantitative benchmarks and, together with airborne carbon dioxide observations and surface ocean pCO2 and temperature observations, reduce uncertainty in model-projected end-of-century Southern Ocean carbon dioxide uptake by 53%.
What the researchers tested
The researchers constrained Southern Ocean productivity south of about 44° S by linking CMIP6-modelled productivity to modelled air-sea O2 fluxes and by applying oxygen flux estimates derived from airborne O2/N2 observations. They also compared these estimates with airborne carbon dioxide observations, surface ocean pCO2, and temperature observations.
What worked and what didn't
CMIP6 models with underestimated productivity showed weak summer carbon dioxide uptake, and some also showed excessive summer temperature-driven outgassing. Together, these models produced incorrect seasonal carbon dioxide flux cycles with summer outgassing, while the observation-based estimates indicated summer uptake.
What to keep in mind
The abstract describes uncertainty in Southern Ocean productivity estimates because of limited observations, but it does not provide additional limitations beyond that scope. The findings are presented for the Southern Ocean south of about 44° S.
Key points
- Southern Ocean net primary production was estimated at 6.5 ± 1.36 PgC yr−1.
- This estimate is higher than most CMIP6 model and satellite-based estimates.
- The estimate is consistent with Argo oxygen-based estimates.
- Models with underestimated productivity showed weak summer carbon dioxide uptake and, in some cases, excessive summer outgassing.
- Using these constraints reduced uncertainty in projected end-of-century Southern Ocean carbon dioxide uptake by 53%.
Disclosure
- Research title:
- Atmospheric oxygen links reveal higher Southern Ocean productivity
- Authors:
- Yuming Jin, Britton B. Stephens, Matthew C. Long, Manfredi Manizza, Nicole S. Lovenduski, Cynthia Nevison, Eric J. Morgan, Ralph F. Keeling
- Institutions:
- NSF National Center for Atmospheric Research, National Institute of Oceanography and Applied Geophysics, Institute of Arctic and Alpine Research, University of Colorado Boulder, Scripps Institution of Oceanography, University of California San Diego
- Publication date:
- 2026-04-21
- OpenAlex record:
- View
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