A diatom-based Holocene palaeoenvironmental record from a mid-arctic lake on Boothia Peninsula, Nunavut, Canada
Bibliographic record
Abstract
A 485 cm sediment core from a lake unoffcially called JR01, Boothia Peninsula, Nunavut, Canada, yielded a high-resolution diatom record documenting environmental change in the mid-arctic. Five radiocarbon dates provided the chronology. Changes in diatom composition and sediment character istics indicated distinct shifts in the Holocene climate. A more diverse and productive diatom flora implies warmer temperatures in the middle Holocene. A subsequent complete shift in diatom composition to a predominantly Fragilaria sensu lato flora and a reduction in diversity and production suggests cooler climates in this region after 4600cal. BP. Smaller-scale climatic fluctuations, such as the‘Little Ice Age’ (LIA, 600–150 cal. BP) and the‘Mediaeval Warm Period’ (MWP, 1150–600 cal. BP), caused shifts in the diatom flora and production. Subtle shifts in floristic diversity within the LIA may reflect climatic variability at a century scale. A gradual shift to a more diverse and productive flora in the last 150 years suggests a response to the recent warming trend.
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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 | 0.002 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".