Greenhouse gas balance of thermokarst fens and bogs in the discontinuous permafrost zone during extreme drought years
Bibliographic record
Abstract
The greenhouse gas (GHG) balance of northern peatlands is being influenced by the combined effects of rapid permafrost thaw and increasing frequency and severity of droughts. Our soil chamber flux measurements revealed that thermokarst fens in the discontinuous permafrost zone of boreal western Canada (Lutose, Alberta) acted as stronger net sources of carbon dioxide (CO2) and consistently emitted more methane (CH4) than thermokarst bogs during two extreme-drought years. Peatlands in the discontinuous permafrost zone store large amounts of soil carbon, but thawing permafrost results in changes to hydrology and vegetation, which have the potential to substantially impact their greenhouse gas balance. As permafrost thaws, thermokarst bogs and fens develop and expand, further modifying GHG dynamics. Although thermokarst fens account for approximately 30% of peatlands in the discontinuous zone, they have received little attention, and there is limited understanding of how the GHG balance varies along the trophic gradient from poor fens to extreme-rich fens.This study explored the spatial and temporal variability of greenhouse gas fluxes across four sites, including a thermokarst bog, poor fen, rich fen, and an extreme-rich fen. Trophic status of each site was classified based on pH, electrical conductivity (EC), vegetation, and concentrations of magnesium (Mg) and calcium (Ca). Fluxes were measured over two growing seasons and one winter (June 2023 to October 2024). Controls on greenhouse gas fluxes were explored using data on vegetation composition, water chemistry, hydrology, and climatic conditions. Our analysis showed that CH4 emissions generally increased along the trophic gradient, with the exception of the extreme-rich fen, where high sulfate concentrations suppressed emissions. Non-growing season CH4 emissions were also a significant contributor to annual emissions across all sites.Overall, our findings indicate that trophic status plays an important role in determining the greenhouse gas balance of thermokarst bogs and fens following permafrost thaw. Understanding the drivers of the carbon dioxide balance and methane emissions in these ecosystems during extreme drought years is essential for refining models of peatland carbon dynamics and predicting their future role in the global carbon cycle as climate change continues.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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".