Early impacts of Arctic amplification in the western North Water Polynya: A 400-year perspective
Bibliographic record
Abstract
The North Water (NOW) polynya in northern Baffin Bay is known for persistent open water, attracting marine mammals and birds during winter. Ice bridges forming north of the NOW at constriction points in Nares Strait aid in sustaining these open water conditions. However, Arctic Amplification has weakened these ice bridges, altering water and sea ice flow into the NOW. We examined the effect of climate warming and recent ice bridge failures through 400 years of changes in the western NOW. We analyzed dinoflagellate cyst (dinocyst) assemblages in a surface sediment transect across the NOW to assess their distribution as indicators of surface water masses. We then analyzed dinocysts and geochemical proxies (carbon and nitrogen signatures) from two sediment cores in the western NOW. Results show the eastern NOW, influenced by the West Greenland Current (WGC), exhibits higher contributions of mixotrophic taxa and total dinocyst concentrations than the western region, influenced by Arctic water outflow. Sediment cores show a 300-year period of stability in the western NOW (1620–1920 CE), followed by an increase in mixotrophic taxa and total dinocyst fluxes, predating observed ice bridge failures. Around 1980 CE, higher abundances of Operculodinium centrocarpum , and cysts of Polarella glacialis and Pentapharsodinium dalei , suggest early sea ice retreat, seemingly attributable to increased WGC influence. These findings demonstrate the early impact of Arctic Amplification on the NOW, with significant changes starting in the first half of the 20th century, which contribute to understanding the timing and propagation of oceanographic changes in the polynya. • Dinoflagellate cyst assemblages in sediment reflect distinct currents in the NOW. • Relatively stable sea-surface conditions in the western NOW from 1620 and 1920 CE. • Changes in dinoflagellate cyst fluxes and assemblage composition around 1920 CE. • Notable changes in the Western NOW precede modern Nares Strait ice bridge instability.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.000 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".