Neodymium isotopes trace marine provenance of Arctic sea ice
Bibliographic record
Abstract
Radiogenic neodymium (Nd) isotopes ( Nd ) have the potential to serve as a geochemical tracer of the marine origin of Arctic sea ice. This capability results from pronounced Nd differences between the distinct marine and riverine sources, which feed the surface waters from which the ice forms. The first dissolved Nd isotope and rare earth element (REE) concentration data obtained from Arctic sea ice collected across the Fram Strait during RV Polarstern cruise PS85 in 2014 confirm the incorporation and preservation of the parental surface seawater Nd signatures despite efficient REE rejection. The large Nd variability between ice floes and within sea ice cores (-32 to -10) reflects changes in water mass distribution during ice growth and drift from the central Arctic Ocean to Fram Strait. In addition to the parental seawater composition, our new approach facilitates the reconstruction of the transfer of matter between the atmosphere, the sea ice and the ocean. In conjunction with satellite-derived drift trajectories, we enable a more accurate assessment of sea ice origin and spatiotemporal evolution, benefiting studies of sea ice biology, biodiversity, and biogeochemistry.
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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 | 0.000 |
| 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) | 0.001 | 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".