Exercise and emersion in air and recovery in seawater in the green crab (<i>Carcinus maenas</i>): Effects on nitrogenous wastes and branchial chamber fluid chemistry
Bibliographic record
Abstract
Abstract At low tide, the green crab, which is capable of breathing air, may leave the water and walk on the foreshore, carrying branchial chamber fluid (BCF). N‐waste metabolism was examined in crabs at rest in seawater (32 ppt, 13°C), and during 18‐h recovery in seawater after 1 h of exhaustive exercise (0.25 BL s−1) on a treadmill in air (20°C–23°C), or 1 h of quiet emersion in air. Measurements were made in parallel to O2 consumption (ṀO2), acid‐base, cardio‐respiratory, and ion data reported previously. At rest, the ammonia‐N excretion rate (ṀAmm = 44 µmol‐N kg−1 h−1) and ammonia quotient (AQ; ṀAmm/ṀO2 = 0.088) were low for a carnivore. Immediately after exercise and return to seawater, ṀAmm increased by 65‐fold above control rates. After emersion alone and return to seawater, ṀAmm increased by 17‐fold. These ammonia‐N bursts were greater, but transient relative to longer‐lasting elevations in ṀO2, resulting in temporal disturbances of AQ. Intermittent excretion of urea‐N and urate‐N at rest and during recovery indicated the metabolic importance of these N‐wastes. Hemolymph glutamate, glutamine, and PNH3 did not change. Hemolymph ammonia‐N, urea‐N, and urate‐N concentrations increased after exercise and more moderately after emersion, with urate‐N exhibiting the largest absolute increments, and urea‐N the longest‐lasting elevations. All three N‐wastes were present in the BCF, with ammonia‐N and PNH3 far above hemolymph levels even at rest. BCF volume declined by 34% postemersion and 77% postexercise, with little change in osmolality but large increases in ammonia‐N concentrations. Neither rapid flushing of stored BCF nor clearance of hemolymph ammonia‐N could explain the surges in ṀAmm after return to seawater.
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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".