<scp>CDOM</scp> spectral slope (<scp><i>S</i></scp><sub>275–295</sub>) as tracers of water masses, <scp>CDOM</scp> heterogeneity, and <scp>Δ<sup>14</sup>C‐DOC</scp> in an oligotrophic marginal sea
Bibliographic record
Abstract
Abstract The absorption spectral slope, S275–295, is an optical metric frequently employed for characterizing chromophoric dissolved organic matter (CDOM). We collected CDOM absorption (aCDOM) and fluorescence spectra from the oligotrophic offshore South China Sea to identify the major determinant of S275–295 and to explore the potential of S275–295 as physical and biogeochemical tracers. S275–295 linearly decreased with increasing humic‐like fluorescent DOM, revealing the latter as the primary control on S275–295. The variability of S275–295 consistently declined from the surface to deep water, making S275–295 a potential indicator of CDOM molecular heterogeneity. The S275–295 vs. aCDOM plot was found to be a useful tool for characterizing water masses. The 14C content of dissolved organic carbon (Δ14C‐DOC) shows a strong correlation to S275–295, demonstrating S275–295 to be a proxy of the 14C‐age of DOM. A provisional equation, ln(−Δ14C‐DOC) = (−0.85 ± 0.06) × ln(S275–295) + (8.78 ± 0.19), was proposed to estimate Δ14C‐DOC from S275–295 for global oligotrophic oceans.
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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 | 0.000 | 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 | 0.000 |
| 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".