Carbon accumulation in discontinuously frozen peatlands, southwestern Northwest Territories, Canada
Bibliographic record
Abstract
Rates of carbon and peat accumulation were studied in a series of peat landforms within discontinuously frozen peatlands near Fort Simpson, Northwest Territories. An extended distribution of the White River volcanic ash layer was used as a chronostratigraphic horizon to ensure a consistent time span of peat deposition among peat cores and to allow a large core sample size without the expense of radiocarbon dating. Apparent recent carbon accumulation rates measured over the past 1200 years were not significantly different among rich fen, peat plateau, and collapse fen (means 13--14 g C M-2 yr-1). Poor fen and bog mean accumulation rates were 20--22 g C M-2 yr -1 and were not significantly different from each other. Microtopography and water table position appear to be important controls on both carbon and vertical peat accumulation rates. A regional survey incorporating measurements from other parts of the southwestern Northwest Territories and the southeastern Yukon shows rates similar to those near Fort Simpson. The aggradation of permafrost results in 50 and 65% decreases in carbon and vertical peat accumulation rates, respectively. Carbon and peat accumulation continue to decrease significantly with both increasing permafrost maturity and the number of ground fires. The internal degradation of permafrost results in nearly a doubling in carbon accumulation rates, yet permafrost degradation at the margins of a peat plateau results in carbon accumulation rates similar to the peat plateau. Clymo's (1984) carbon accumulation model was applied to cores from each landform in addition to a core spanning the entire developmental history of the peatland. Results indicate that true carbon accumulation and sequestration efficiency rates in ombrotrophic peatlands are lower in the upper Mackenzie Valley than for other boreal regions, primarily owing to high decomposition rates. The cessation of carbon accumulation is being approached. The model also serves to highlight the dangers of using apparent and true carbon accumulation rates interchangably. Apparent and true carbon accumulation rates are significantly lower than published rates from other parts of northern Canada, Finland, and the Former Soviet Union. Low and variable summer precipitation in the region may be a significant factor through increased aerobic decomposition and/or decreased plant production caused by moisture stress.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".