Climate and ocean changes in the western Hudson Strait over the last 6000 years
Bibliographic record
Abstract
A record of marine and terrestrial palynomorphs from a sediment core collected from the western Hudson Strait provided evidence of past climatic and hydrographic variability over the last 6000 years with a decadal to multidecadal temporal resolution. The sequence is characterized by high and uniform sediment accumulation rates of about 0.1 cm/year. Throughout the sequence, dinoflagellate cysts (dinocysts) and organic linings of benthic foraminifers are very abundant, ranging up to ∼16,000 cysts/cm 3 and ∼2500 organic linings/cm 3 respectively, indicating high primary production and organic carbon fluxes. The dinocyst assemblages are dominated by the cyst of Pentapharsodinium dalei and Brigantedinium spp., and Islandinium minutum subsp. minutum , mainly accompanied by Operculodinium centrocarpum , Spiniferites ramosus , S. elongatus , Islandinium ? cezare and Echinidinium karaense . Such an assemblage is typical for highly productive seasonally ice-free environments. The reconstruction of sea-surface parameters based on dinocyst assemblages indicates warmer conditions from the base of the core until ⁓2750 cal yr BP. Subsequently, a cooling trend was marked by more extensive seasonal sea-ice cover spanning up to 9 months/yr, and fluctuating conditions of salinity. In the pollen assemblages, Alnus and Betula abundance decreased upcore while Ericaceae increased, which we associate with harsher climatic conditions. Hence, both pollen and dinocyst data point to a cooling trend, with a main transition occurring between 2700 and 2000 cal yr BP. • The data evidence an abrupt change toward colder conditions with extensive sea-ice cover about 2750 years ago. • Particularly unstable sea-surface conditions were recorded after 2000 cal years BP. • The pollen data also suggest a cooling trend, notably marked by increased Ericaceae pollen after 2500 cal years BP.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".