Characterizing Vadose Zone Hydrocarbon Biodegradation Using Carbon Dioxide Effluxes, Isotopes, and Reactive Transport Modeling
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Naturally occurring biodegradation of hydrocarbon compounds may offer a sustainable management option at contaminated sites. However, a sound understanding of contaminant mass loss rates is required to enable estimation of source zone longevity, serving to alleviate public concerns and inform decision makers. Under some conditions, surficial CO 2 efflux measurements can be useful to delineate petroleum hydrocarbon containing source zones, and to provide estimates of depth‐integrated vadose zone hydrocarbon degradation rates. However, the accuracy of degradation rate estimates is limited by our ability to separate CO 2 effluxes associated with contaminant decomposition from those attributable to naturally occurring soil respiration. To understand CO 2 sources and transport processes within the vadose zone, this work combines measurement of surficial CO 2 effluxes with detailed analysis of soil gas composition– including the radiocarbon and stable isotopic composition of CO 2 . Quantitative reactive transport modeling allows further evaluation of controls on CO 2 generation and fate, and CH 4 generation and oxidation. Results confirm that, in the source zone at the Bemidji site, the majority of CO 2 originates from degradation of the oil body. In addition, radiocarbon in CO 2 proves particularly useful in determining the contribution of contaminant degradation to the measured CO 2 efflux.
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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 | 0.001 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 it