Use of Stable Carbon and Nitrogen Isotopes to Trace Natural and Anthropogenic Inputs into Riverine Systems in the Athabasca Oil Sands Region
Bibliographic record
Abstract
Abstract Stable isotopes of carbon and nitrogen in fish were examined as a potential tracer of exposure to oil sands constituents in naturally eroded environments and in areas of anthropogenic activity (municipal and industrial effluent discharges; oil sands surface mining) within the Athabasca River drainage basin of northern Alberta, Canada. Longnose sucker (Catostomus catostomus), trout-perch (Percopsis omiscomaycus), and slimy sculpin (Cottus cognatus) showed changes in δ13C values with the river gradient. Site-specific differences in the δ13C values of fish were more pronounced for the small-bodied fish species in the lower reaches of a tributary (slimy sculpin) and immediately downstream of tributary inputs along the Athabasca River (trout-perch), where potential exposure to the oil sands constituents is elevated. There were also species and site-specific trends for δ15N values. Site-specific trends attributed to municipal or industrial effluent discharge or tributary inputs may prove to be a useful tool for defining residency on the oil sands deposit. This study has provided baseline data of isotope values for fish species which are currently used (longnose sucker) or may be used in future environmental effects monitoring programs. Defining residency and exposure to the oil sands deposit is critical to establishing exposure-response relationships, particularly since there are new expansions to oil sands mining operations.
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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 | 0.001 |
| 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".