Physiological Plasticity and Tolerance of Fundulid Killifish Species to Aquatic Hypoxia
Bibliographic record
Abstract
Aquatic hypoxia is a naturally occurring phenomenon in waters subject to high primary production, eutrophication, and salinity‐derived stratification. Fish utilize a suite of physiological responses in order to cope with aquatic hypoxia. Species that regularly experience repeated bouts of hypoxia may rely more heavily on compensatory responses in order to survive. We hypothesized that species from hypoxia‐prone environments such as estuaries are more tolerant to hypoxia than species living in stable environments. We also hypothesized that species from variable environments would show a greater scope for phenotypic plasticity in their physiological acclimation responses to hypoxia. Fundulid killifish species from different ecological niches (marine‐tolerant Lucania parva and Fundulus confluentus and freshwater‐tolerant L. goodei and F. rathbuni ) were acclimated for 21–28 d to either constant hypoxia or diurnal cycles of intermittent hypoxia (12 h normoxia: 12 h hypoxia). We then assessed the resting O 2 consumption rates and hypoxia tolerance (critical O 2 tension, O 2 tension at loss of equilibrium, and time to loss of equilibrium at 0.6 kPa O 2 ). Our results show that F. confluentus , an estuarine killifish, demonstrated much greater hypoxia tolerance than F. rathbuni, which inhabits freshwater rivers and creeks. Also, the sister taxa, L ucania parva and L. goodei demonstrated very similar baseline hypoxia tolerance. Acclimation to intermittent or constant hypoxia often (but not always) significantly improved hypoxia tolerance, but there were no clear patterns of variation in this plasticity between species from different environments. Our data suggest that plasticity can vary between even closely related species. Future work will compare the unique physiological strategies of each species for coping with hypoxia. Support or Funding Information We would like to thank the American Physiological Society's Undergraduate Summer Research Fellowship program, Louisiana Sea Grant, Louisiana State University, McMaster University, the Society of Experimental Biology, the National Science Foundation, and the Natural Sciences and Engineering Research Council of Canada for funding and support.
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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 | 0.001 |
| 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".