Spectrofluorescence of Sediment Humic Substances and Historical Changes of Lacustrine Organic Matter Provenance in Response to Atmospheric Nutrient Enrichment
Bibliographic record
Abstract
Humic substances were extracted from the sediments of two small alpine lakes in the Colorado Front Range and characterized by three-dimensional fluorescence spectroscopy. The fluorescence index (FI), defined as the ratio of fluorescence emitted at 450 nm to that emitted at 500 nm from an excitation wavelength of 370 nm, was computed and thereafter compared to additional sediment proxies of recent environmental change. Stratigraphic changes in both sediment C:N ratios and diatom assemblages parallel those of Fl, together indicating pronounced increases in the contribution of autochthonous organic matter to lake sediments since the mid-20th century. This result is consistent with increased algal production attributable to nutrient enrichment, given thatthe region undergoes episodic nitrogen saturation in response to anthropogenic N emission. The validation of sediment Fl measurements through comparisons with independent methods demonstrates the utility of this technique for characterizing shifts in the provenance of lake sediment organic matter arising from changing environmental conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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) | 0.001 | 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 teacher head, 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".