The influence of nitrogen limitation on d15N and carbon : nitrogen ratios in sediments from sockeye salmon nursery lakes in British Columbia, Canada
Bibliographic record
Abstract
Carbon (C) and nitrogen (N) elemental and nitrogen isotopic ratios were determined for bulk organic matter in surface sediments of 11 sockeye salmon (Onchorynchus nerka) nursery lakes in British Columbia, Canada. Chitinous exoskeletons of Bosmina spp. were also picked from the sediments and analyzed for Δ15N. The correlation between salmon escapement (spawner abundance) and bulk organic Δ15N confirms the importance of marine-derived nitrogen to the study lakes. The relation between sediment Δ15N and escapement, however, suggests that simple mixing models may significantly underestimate spawner abundance in nitrogen-limited lakes. In addition, the use of sediment and chitin Δ15N and C:N data to characterize lake-specific differences demonstrates that sediment isotope signatures are dependent on attendant nitrogen deficiency. The sediment C:N ratio, on its own, provides a sensitive measure of nutrient status in these lakes. This finding provides an alternate additional interpretation of C:N ratios that may be more appropriate in large lakes where terrestrial contributions to the central basin are insignificant.
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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 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 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".