Last glacial maximum (LGM) primary productivity in the northern North Atlantic OceanThis article is one of a series of papers published in this Special Issue on the theme <i>Polar Climate Stability Network</i>.
Bibliographic record
Abstract
To reconstruct oceanic primary productivity in the northern North Atlantic Ocean during the last glacial maximum (LGM), we have applied the modern analogue technique to dinocyst assemblages using a Northern Hemisphere database that includes 1171 reference sites. The reconstructions were made in LGM sediments (21 ± 2 ka) of a set of 62 cores collected from 36°N to 75°N. Here, we present the compilation of reconstructed seasonal and annual productivity during the LGM. Results show lower mean annual productivity during the LGM than at present in the northern North Atlantic. At most high-latitude locations, LGM productivity has been estimated at <200 gC m –2 a –1 , with extremely low values (<100 gC m –2 a –1 ) in the Labrador Sea, Baffin Bay, and along the margins of Greenland. Such low values might be the result of reduced Atlantic Meridional Overturning Circulation and stratified water that characterized the glacial episode of the North Atlantic 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 | 0.001 |
| 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) | 0.001 | 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".