Overwintering physiology of juvenile Crassostrea virginica at its northern distribution limit
Bibliographic record
Abstract
Eastern oysters Crassostrea virginica reside at their northern geographic limit in the Gulf of St. Lawrence, Canada, where they experience sub-zero temperatures in winter. To survive, adult oysters adjust cell membrane fluidity through changes in the fatty acid composition of their lipid membranes and enter a period of dormancy marked by strong metabolic depression. Unlike the adult stage, the metabolic strategies of oyster seed during winter remain understudied. To gain initial insights into overwintering in this life stage, we conducted 2 experiments (2021-2022 and 2022-2023) monitoring the fatty acid composition of polar lipids and levels of energetic reserves. We also performed a third experiment on hatchery-produced seed to determine if dormancy could be induced by storing them at low temperatures (2° and 6°C). Results from the overwintering trials showed marked physiological changes in December to January, coinciding with temperatures falling below 2°C. Cessation of membrane fluidity regulation was observed in response to cold temperatures, alongside significant glycogen reserve mobilization that lasted until the end of dormancy. The storage experiment revealed that seed fed and accumulated energy reserves at 6°C, but not 2°C, suggesting the existence of a threshold for dormancy between these 2 temperatures. Overall, our findings indicate that while both adults and seed enter winter dormancy, the physiological mechanisms underlying this state differ markedly. While adults regulate membrane fluidity during dormancy, seed cease this regulation despite declining temperatures. This may reflect a physiological trade-off: conserving energy reserves (limited in seed) until feeding resumes at the end of dormancy, rather than expending energy to regulate membrane fluidity.
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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 | 0.000 | 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) | 0.001 | 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".