Salmon‐derived mercury and nutrients in a Lake Ontario spawning stream
Bibliographic record
Abstract
We tested the hypothesis that concentrations of mercury species (Hg) and nutrients (NH4+, NO3−, P, and dissolved organic carbon) in abiotic and biotic components would be altered by the decomposition of salmon carcasses in streams. We investigated a tributary stream of Lake Ontario receiving spawning runs of Chinook salmon (Oncorhyncus tshawytscha) for 2 yr with contrasting bear activity. Stations with high carcass densities had significantly higher levels of aqueous total Hg, methylmercury (MeHg), particulate Hg, and nutrients than did stations with lower carcass densities. Hg levels in aquatic and terrestrial invertebrates feeding on carcasses increased by up to 25‐fold. In 2001, a bear removed most carcasses at the downstream station, and aqueous Hg and nutrient concentrations were significantly lower than during the preceding year, when no bear was active at that station. A preliminary budget for this stream shows that (1) salmon carcasses can be an important source of Hg and nutrients to aquatic and terrestrial food webs, and (2) terrestrial invertebrates and vertebrates can be important water‐to‐land vectors of Hg.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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 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".