Diurnal and seasonal variation in methane emissions in a northern Canadian peatland measured by eddy covariance
Bibliographic record
Abstract
Abstract Eddy covariance measurements of methane (CH 4 ) net flux were made in a boreal fen, typical of the most abundant peatlands in western Canada during May–September 2007. The objectives of this study were to determine: (i) the magnitude of diurnal and seasonal variation in CH 4 net flux, (ii) the relationship between the temporally varying flux rates and associated changes in controlling biotic and abiotic factors, and (iii) the contribution of CH 4 emission to the ecosystem growing season carbon budget. There was significant diurnal variation in CH 4 emission during the peak of the growing season that was strongly correlated with associated changes in solar radiation, latent heat flux, air temperature and ecosystem conductance to water vapor. During days 181–215, nighttime average CH 4 efflux was only 47% of the average midday values. The peak value for daily average CH 4 emission rate was approximately 80 nmol m −2 s −1 (4.6 mg CH 4 m −2 h −1 ), and seasonal variation in CH 4 flux was strongly correlated with changes in soil temperature. Integrated over the entire measurement period [days 144–269 (late May–late September)], the total CH 4 emission was 3.2 g CH 4 m −2 , which was quite low relative to other wetland ecosystems and to the simultaneous high rate of ecosystem net CO 2 sequestration that was measured (18.1 mol CO 2 m −2 or 217 g C m −2 ). We estimate that the negative radiative forcing (cooling) associated with net carbon storage over the life of the peatland (approximately 2200 years) was at least twice the value of positive radiative forcing (warming) caused by net CH 4 emission over the last 50 years.
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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) | 0.000 | 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 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".