Marine nitrogen in central Idaho riparian forests: evidence from stable isotopes
Bibliographic record
Abstract
Terrestrial and marine ecosystems are linked by the annual migration of salmonids. We examined the contribution of anadromous fish to foliar nitrogen (N) in central Idaho riparian forests where anadromous fish have been in sharp decline for approximately 30 years. To determine if the amount of N from anadromous fish carcasses can be assessed from conifer foliage, we fertilized seedlings with varying proportions of N from marine sources and analyzed their foliar 15N/14N ratio (δ15N). Also, to evaluate whether N obtained from marine sources was evident in riparian forests, we analyzed the δ15N of conifer foliage, above and below waterfalls, along historically salmon-bearing and non-salmon-bearing streams and rivers in central Idaho. In the seedling study, the amount of marine N was positively correlated with foliar δ15N. Furthermore, we determined that foliar δ15N values in riparian forests were explained by the historical occurrence of salmon. Foliar δ15N declined significantly from bankside to upslope trees in transects along salmon-bearing streams and rivers, whereas there was no significant gradient along transects perpendicular to non-salmon-bearing reaches. We therefore conclude that marine nutrient sources have historically contributed to the N pool in riparian conifer forests and marine N persisted following 30 years of severe populations declines.
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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".