Pressure variations in peat as a result of gas bubble dynamics
Bibliographic record
Abstract
Abstract Transient high pore‐water pressures, up to 50 cm higher than ambient pressure, developed over the summer season at various depths in a shallow (1 m) fen peat. The excess pressures had a pattern of gradual increases and sharp drops, and their initiation and release typically corresponded to abrupt changes in atmospheric pressure. We conclude that these phenomena depend on gas bubbles (probably methane) generated by biological activity, both by clogging pores and by building up pressure as they grow. These transient and spatially discontinuous high‐pressure zones were found using pressure transducers in sealed (backfilled) pits, but not in piezometers open to the atmosphere. Piezometers may provide a conduit for the release of gas and pressure, thus rendering them unsuitable for measuring this phenomenon. Although the development of localized zones of high pressure causes erratic and unpredictable hydraulic gradients, we suggest that their effect on the flow of water or solutes is offset by the reduced permeability caused by the bubbles, which allows them to be sustained. These zones, however, probably deflect flows driven by the dominant hydraulic gradients. Furthermore, they may cause the peat volume to adjust (swell). The use and interpretation of traditional methods for estimating hydraulic head and conductivity in peat soils thus require great caution. Copyright © 2004 John Wiley & Sons, Ltd.
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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".