Gas ventilation of the Saguenay fjord by an energetic tidal front
Bibliographic record
Abstract
Abstract Dissolved noble gas samples were taken during a pilot study in the Saguenay Fjord, Quebec, Canada, in order to determine the contribution of different air‐sea gas exchange mechanisms in an estuary and to assess the contribution of tidal fronts to the aeration of subsurface waters. The noble gases He, Ne, Ar, Kr, and Xe span a large range of molecular diffusivities and solubilities and hence constitute a useful probe of various gas exchange and bubble injection processes. Samples were taken at flood tide upstream and downstream of an energetic tidal front that is generated by a hydraulically controlled flow over a shallow sill at the entrance to the Fjord. The results are interpreted with the help of hydrographic measurements of density and currents along cross‐sill transects describing the physical forcing at the sill. High gas saturations downstream of the sill indicate the aeration of water within the frontal region. An inverse model is used to compare the contribution of bubble injection in the front to diffusion across the air‐sea interface. The large ratio of completely ‘trapped’ bubbles to diffusion suggests that bubbles injected by waves breaking in the front contribute significantly to air‐sea gas exchange with 76% for He, 79% for Ne, 56% for Ar, 47% for Kr, and 35% for Xe. Water samples were analyzed for helium isotopes and tritium in order to explore the possibility of constraining ventilation time scales. The relationship between tritium and salinity revealed two end‐member waters: a freshwater component from the Saguenay River of 23.6 ± 0.5 TU, likely a residual of bomb‐produced tritium, and a seawater end‐member of approximately 1.5 TU originating in the subpolar Atlantic. An unexpected contribution of radiogenic 4He was detected in the deep waters of the St. Lawrence Estuary, likely a consequence of out‐gassing from old, uranium and thorium rich granitic terrain.
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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 | 0.000 |
| 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 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".