Progressive oxygenation of the North Atlantic subpolar gyre
Bibliographic record
Abstract
The subpolar North Atlantic (SPNA) is one of the few regions where the deep ocean is in direct contact with the atmosphere, making it a key location for interior ocean ventilation through gas exchange. We use observational data to analyze large-scale patterns of mean annual air-sea flux, biological production and consumption, and physical transport of oxygen for the subpolar North Atlantic Ocean (45N-65N), finding a net annual flux of 48.1±14.6 Tmol (1Tmol = 1012 mol) of oxygen from the atmosphere into the ocean, largely balanced by a removal of oxygen through physical transport. Wintertime increases in oxygen content in isopycnal layers match the location and magnitude of net oxygen uptake from the atmosphere, supporting the connection between air-sea gas exchange at the surface and ventilation of deeper layers. Integrated over the whole SPNA, 90% of the net oxygen influx and 80% of the seasonal oxygen content increase occur at densities of σ0 < 27.6 kg m-3, in the upper branch of the Atlantic Meridional Overturning Circulation (AMOC). The subpolar gyre (SPG) is ventilated with oxygen largely at these lower densities, accumulating oxygen along its cyclonic pathway from the North Atlantic Current towards the Labrador Sea. Our results thus suggest that the subpolar gyre is oxygenated cumulatively throughout the SPNA, as mode waters formed each winter become progressively denser and more oxygenated along the SPG’s path, culminating in the oxygen-rich Labrador Sea Water which is ultimately exported to the rest of the ocean in the lower branch of the AMOC.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".