Diatom community responses to late-Holocene climatic variability, Baffin Island, Canada: a comparison of numerical approaches
Bibliographic record
Abstract
A high-resolution diatom stratigraphy from the late-Holocene sediments of a small Arctic lake on Baffin Island (Nunavut, Canada) has been analysed by several numerical methods and considered in relation to independent palaeoclimatic proxies to enable an objective assessment of the response of freshwater diatom communities to climatic change. Diatom relative frequencies and absolute abundances were subjected to several manipulations, including application of a weighted-averaging transfer function for summer water temperature, conversion of valve concentrations to cell biovolumes, biostratigraphic rate-of-change, and taxonomic richness estimated by rarefaction analysis. The major directions of variability within the derived diatom data were explored using principal components analysis. Diatom-inferred lakewater temperatures and indices of diatom palaeoproductivity declined during late-Holocene cooling, and they faithfully record post-‘Little Ice Age’ warming. Between ~2000 cal. BP and the ‘Little Ice Age’, which includes the coldest intervals of the Neoglacial, diatom assemblages diversified and destabilized, reflecting a state of intermediate disturbance. Together, these results examine different methods of interpreting freshwater diatom stratigraphic data with the objective of gaining palaeoclimatic insights from fossil assemblages.
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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 | 0.001 | 0.002 |
| 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 | 0.001 | 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".