Laboratory study on the impact of pH and salinity on the fluorescence signal of Natural Organic Matter (NOM) relevant to groundwaters from a Canadian Shield sampling site
Bibliographic record
Abstract
Fluorescence spectroscopy with the spectral resolution routine PARAFAC is a leading tool to analyze Natural Organic Matter (NOM) in waters. This routine resolves spectra into humic-, fulvic- and protein-like components, which helps interpret the NOM dynamics in environmental systems. This work is one of the first systematic studies dealing with the impact of chemical perturbations on the fluorescence spectral interpretation of NOM. The samples, taken at two Canadian Shield locations (a shallow set and a deep set to ∼650 m), were perturbed for pH (‘titrations’ from pH 4 to 10) and salinity (from ∼0.02 to 3‰ salt content), then analyzed by fluorescence/PARAFAC. Our fluorescence signals for the three components showed no clear change with pH, as would be expected with a classic titration. The signals were reproducible between replicates for the humic- and protein-like components, but less so for the fulvic-like components. Changes of salinity only had a small impact on the fluorescence signal (a ∼2.7–3.4% signal decrease for each salinity unit, ‰) for the three components in this salinity range.
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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 | 0.008 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".