Simultaneous measurement of 0,, Mn, Fe, I-, and S(-II) in marine pore waters with a solid-state voltammetric microelectrode
Bibliographic record
Abstract
A solid-state AufHg voltammetric microelectrode was used to measure, simultaneously and with millimeter spatial resolution, the vertical distributions of O,, Mn’+, Fe 2+ HS-, and I, in the pore water of sediments from the Canadian continental shelf and slope. The electrode was used shipboard to analyze undisturbed sediment cores and in a sediment mesocosm to determine the three-dimensional distribution of redox species in the sediment surrounding an actively irrigated worm burrow. In cores from Emerald Basin and Cabot Strait, 0, disappeared and Mn ’ ’ , FeL, and HS appeared in the vertical sequence predicted on the basis of thermodynamics. In a core from the Scotian slope, Oz disappeared at-14-mm depth but Mn’+ was not detected over the 50-mm depth examined with the probe. In all three cores, I was detected in the pore water below the oxygen-penetration depth. In none of the cores did the distributions of OL and Mn’+overlap. The thickness of the layer within which neither Oz nor Mn ” could be detected ranged from 8 to 40 mm; we suggest that nitrate, not oxygen, is used to oxidize Mn”. The upward-directed Mn ” gradients of 3.5 and 10 mol mm4 in the Emerald Basin and Cabot Strait sediments, respectively, drive manganese fluxes that are more than one order of magnitude lower than the O2 fluxes, which are estimated at 4-S mmol mm ’ d I. The three-dimensional distributions of solutes in the pore water in the sediment surrounding an irrigated worm burrow demonstrate that both the Oz-penetration depth and the depth where Mn ” is first detected
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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) | 0.000 | 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".