Exercise and emersion in air, and recovery in seawater in the green crab (<i>Carcinus maenas</i>): metabolic, acid–base, cardio-ventilatory and ionoregulatory responses
Bibliographic record
Abstract
In nature, the green crab exhibits emersion and terrestrial activity at low tide. Treadmill exercise in air (20-23°C) of crabs acclimated to 32 ppt seawater (13°C) revealed an inverse relationship between velocity and duration: 2.0 body lengths (BL) s-1 was sustainable for several minutes, and 0.25 BL s-1 was sustainable for long periods. Fatigue was not due to dehydration. Physiological responses over an 18 h recovery in seawater after near-exhaustive exercise (0.25 BL s-1, 1 h) in air were compared with responses after quiet emersion (1 h) in air. Exercising crabs exhibited transient scaphognathite slowing and progressive increases in heart rate, whereas emersed crabs exhibited persistent inhibition of ventilation and transient heart slowing. Upon return to seawater, all these rates increased above both control and treatment levels. Post-exercise disturbances were more marked and/or longer lasting (e.g. EPOC, hyperventilation, tachycardia, metabolic acidosis, lactate elevation, ionic disturbances) than those after simple air exposure. However, an increase in net acidic equivalent excretion to the environment occurred after emersion but not after exercise. Instead, post-exercise crabs relied on carapace buffering, signalled by elevated haemolymph Ca2+ and Mg2+. Prolonged lowering of haemolymph PCO2 associated with hyperventilation also played a key role in acid-base recovery. EPOC after exercise was 3-fold greater than after emersion, sufficient to support resting ṀO2 for >14 h. This reflected clearance of a large lactate load, likely by glycogen re-synthesis rather than oxidation. We conclude that the amphibious green crab uses a combination of aquatic and terrestrial strategies to support exercise in air, emersion in air and recovery in seawater.
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 | 0.001 | 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".