Interspecific and spatial variation in muscle sulphur compositions and their relation to mercury concentrations for northern freshwater fishes
Bibliographic record
Abstract
We explored patterns in muscle sulphur to nitrogen ratio (S:N) and sulphur stable isotope ratios (δ34S) and their relationships with muscle total mercury concentrations ([THg]) for fishes of 13 coastal rivers and 18 inland lakes ( n = 1370 fish) from northern Ontario, Canada. Muscle S:N decreased and δ34S increased with increasing latitude across populations but neither showed consistent ontogenetic variation within populations. Relative differences among species were similar between rivers and lakes for S:N, but not for δ34S. The piscivore walleye ( Sander vitreus) had distinctly higher S:N than other species. In coastal rivers, muscle δ34S was highest in purported anadromous species, whereas in lakes muscle δ34S was most frequently highest in walleye. Within populations, [THg] was positively related to δ15N and δ34S, particularly in lakes. Within food webs, [THg] was positively related to δ15N in both coastal rivers and inland lakes, and positively related to S:N in coastal rivers, but not related to δ34S in either habitat. Our results further our understanding of sulphur in freshwater food webs and its association with mercury dynamics.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".