Recent change in organic carbon flux to Arctic Ocean deep basins: Evidence from acid volatile sulfide, manganese and rhenium discord in sediments
Bibliographic record
Abstract
Evidence of recent large‐scale change in redox conditions in Arctic Ocean basin sediments is found in profiles of solid phase acid volatile sulfide (AVS), Mn, and Re. AVS occurs at 2.5–5.5 cm in sediment cores collected from all major Arctic basins implying that presently there is a sufficient supply of organic carbon (OC) to deplete O2 and form sulfide. Re, which is mobile under oxic conditions but precipitates under suboxic or anoxic conditions, is not found enriched in the sediments suggesting that AVS is a recent product of enhanced OC fluxes. Estimated diffusion rates suggest that AVS production is recent and that a change from oxic to anoxic diagenesis has taken place within the past 50 y. The most likely origin for such widespread change is the ice climate, and we infer that reduction in ice cover over the past several decades has led to enhanced OC fluxes to the sea floor.
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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 | 0.000 | 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".