Enhanced Transport of Dissolved Methane From the Chukchi Sea to the Central Arctic
Bibliographic record
Abstract
Abstract Rising temperatures in the Arctic Ocean can cause considerable changes, such as decreased ice cover and increased water inflow from the Pacific/Atlantic sector, which may alter dissolved methane (CH4) cycles over the Arctic Ocean. However, the fate of dissolved CH4 in the Arctic remains uncertain. Here, we show that CH4 in the Chukchi Sea is enhanced in the shelf/slope areas, stored in the Upper Halocline (UHC), and transported to the central Arctic, contributing to the CH4 excess (ΔCH4) in the basins. The concentration of ΔCH4 in the UHC was increasing (0.1 nM per year) and the ΔCH4 has been distributed deeper and farther in the last decade than in the 1990s because of the intensification of Pacific water inflow due to oceanographic (currents) and atmospheric forcings (winds). We found heterogeneous CH4 (208.4% ± 131.7%) in the Polar Mixed Layer and CH4 supersaturation (1,100.9%–1,245.4%) in the below‐ice seawater in the basins, which may indicate the effect of sea ice cycles with the support of sediment‐origin CH4. We estimate the sea‐to‐air flux to be 1.1–2.4 μmol CH4 m−2 day−1 during the ice‐free period in the Chukchi Sea, which suggests that the Chukchi Sea is currently a minor source (0.003 Tg in summer) of atmospheric CH4. Taken together, we propose a bottom‐up mechanism for CH4 transport and emission and are concerned that the increases in the concentration of ΔCH4 and the transport distance/rate of ΔCH4 plume are occurring, with the potential to affect CH4 emissions in the Pacific sector of the Arctic Ocean.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.000 | 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".