Bioaccumulation and biomagnification of mercury in Lake Murray, Papua New Guinea
Bibliographic record
Abstract
The bioaccumulation of mercury in the food webs incorporating the major piscivorous fish species of Lake Murray, Papua New Guinea, has been characterised. Methylmercury concentrations increased with trophic level and the proportion of total mercury present as methylmercury increased from <1% in plants to 94% in piscivorous fish. Methylmercury bioaccumulation factors (BAFs) were similar to those found in temperate environments, with a typical increase of 1 log unit between planktivore and piscivore trophic levels. The greatest bioaccumulation of methylmercury occurred between seston and the water column (log BAF of 5.36). The bioaccumulation of mercury to levels of regulatory concern by the lake's piscivores was attributable to the biomagnification power of the plankton-based food chain comprising four trophic levels (phytoplankton, zooplankton, planktivore, piscivore) rather than any elevated concentrations of mercury in waters or sediments. The methylmercury concentrations of individual piscivores were positively correlated with both trophic position, as indicated by δ15N measurements, and fish size. Stable-isotope measurements were used to identify fish species where dietary changes occurring with age significantly augmented age-related bioaccumulation of mercury.
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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 | 0.001 | 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 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".