Methane Emissions to the Atmosphere from the Scotia and Weddell Seas
Bibliographic record
Abstract
The Southern Ocean’s role in the global methane (CH4) cycle remains uncertain due to limited measurement data from this remote region. It is unclear if the Southern Ocean acts as a source or sink of atmospheric CH4, and climatic changes can have consequences on the amount of marine CH4 released due to the acceleration of glacial melting and uncertain consequences on seabed CH4 reservoirs. Monitoring CH4 here is essential to understanding its impact on the global CH4 budget now and in the future. This study measured CH4 concentrations in both ocean and atmosphere during an expedition in the Scotia Sea, Weddell Sea, and South Georgia shelf, linking seabed activity, water column concentrations, sea-air fluxes, and atmospheric CH4 levels. All areas were found to be a small source of CH4 to the atmosphere. Surface water CH4 concentrations varied latitudinally, with lower CH4 levels south of the Southern Antarctic Circumpolar Current front, where upwelling brings CH4-depleted waters to the surface. On-shelf regions show higher CH4 emissions compared to off-shelf, with average sea-air CH4 fluxes of 0.269 ± 0.035 μmolm−2d−1 and 0.136 ± 0.021 μmolm−2d−1, respectively, likely due to seabed seepage and methane-enriched freshwater. This study finds that the Weddell and Scotia seas (including the South Georgia shelf) are a small source of atmospheric CH4. As this result contradicts previous studies identifying this region as a CH4 sink, continued monitoring is needed to understand how emissions are changing and may continue to change in the future.
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".