The ratio of species of Atlantic and Pacific origin in modern Arctic fauna of bivalve molluscs
Bibliographic record
Abstract
The present work aims to estimate the ratio of species of the bivalve molluscs of the Atlantic and the Pacific origin in different geographical and bathymetrical regions of the Arctic basin. Seven shallow-water regions of the Arctic, with depths of 0300 m, (the Norwegian, Barents, Kara, Laptev, East Siberian, Chukchi and Beaufort Seas) and three deep-sea regions with depths exceeding 1000 m (the Norwegian and Greenland Basins, Nansen and Amundsen Basins, Canada Basins) are considered. For the identification of origin we combined fossil records with records of the distribution of living genera and, when possible, used molecular genetic data. The distribution patterns of 265 species from 132 genera were analysed. The share of species of Atlantic origin decreases in marginal Eurasian seas from the Norwegian Sea to the Chukchi Sea, and then increases in the Beaufort Sea. The share of species of Pacific origin is higher only in the Chukchi and Beaufort Seas, the species of the Atlantic and the Pacific origin are equally represented in the East-Siberian Sea. The share of species of the Atlantic origin is much higher in all deep-sea regions. Many taxa of bivalves that dispersed into the Arctic from the North Pacific also penetrated into the North Atlantic. In contrast, most taxa of the Atlantic origin remained in the Arctic Ocean, having stopped at the Bering Strait. Differences between the Arctic boundaries, the Arctic -Atlantic (the Greenland-Iceland-Faeroe Ridge) and the Arctic -Pacific (the Bering Strait) as barriers for dispersal are discussed.
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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 | 0.000 | 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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".