Emission of Volatile Organic Compounds to the Atmosphere from Photochemistry in Thermokarst Ponds in Subarctic Canada
Bibliographic record
Abstract
Climate warming is accelerating the thawing of permafrost, which contains almost twice as much carbon as the atmosphere, to a point where a large quantity of dissolved organic matter (DOM) is being mobilized toward surface waters, including thermokarst ponds. DOM can be partially photodegraded into volatile organic compounds (VOCs), which are little studied in Arctic environments. The main objective of this work is to identify and quantify the VOCs emitted to the gas phase by photochemistry from thermokarst water sampled in four ponds from two study sites in northern Quebec. VOC emissions were characterized by proton-transfer reaction mass spectrometry. Results show rapid photoproduction of between 35 and 59 VOCs when DOM water samples are exposed to radiation. Our results also show that the quality of DOM is a more important factor to control VOC photoproduction than the quantity of DOM. Depending on the assumptions used in upscaling our laboratory results to the field sites, calculations yield net carbon fluxes between 1.93 and 174 μmol C m –2 d –1 . While these values are small compared to literature values of CO 2 and CH 4 fluxes from thermokarst ponds, this process represents an important flux of reactive molecules that could affect Arctic atmospheric chemistry.
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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) | 0.004 | 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".