Sea ice expansion in the Bering Sea during the Neoglacial: evidence from archaeozoology
Bibliographic record
Abstract
The Neoglacial was a period of cold that lasted more than 2000 years during the mid-Holocene, from approximately 4700 to 2500 years ago. Although proxy data from a number of sources document the regional onset and duration of cold conditions in the Northern Hemisphere during this period, none have suggested an expansion of sea ice in the Bering Sea. Here we provide new evidence that Neoglacial sea ice expansion in the Bering Sea was substantial enough to have altered the distribution of North Pacific pinnipeds and cetaceans, using prehistoric skeletal remains recovered from an archaeological site on the island of Unalaska in the eastern Aleutians (Amaknak Bridge, occupied from c. 3500—2500 yr BP (radiocarbon years before present, uncalibrated)). Comprehensive archaeozoological analysis of the Amaknak Bridge fauna indicates that sea ice in the Bering Sea must have reached a more southerly position at the height of the Neoglacial and persisted longer than it does today. We infer from this evidence that for most of the Neoglacial period, sea ice must have surrounded the Pribilof Islands until early summer and blocked the Bering Strait until late summer. Such an expansion and seasonal persistence of sea ice would have prevented fur seals from using the Pribilofs as a summer breeding rookery and whales from making summer migrations into arctic waters to feed, as they do today. We suggest this expansion of sea ice in the Bering Sea during the Neoglacial may explain several unresolved phenomena of mammalian distributions, genetic partitioning and extinctions in the North Pacific.
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".