Thermokarst amplifies fluvial inorganic carbon cycling and export across watershed scales on the Peel Plateau, Canada
Bibliographic record
Abstract
Abstract. The chemical weathering of minerals is a primary control on atmospheric CO2 levels and Earth's climate over geological timescales. As climate warming and precipitation intensify at high latitudes, glaciated terrains across the circumpolar north are poised for rapid geomorphic change and associated changes in mineral weathering dynamics. Here, we determine how the effects of permafrost thaw on mineral weathering sources and inorganic carbon cycling and export integrate across watershed scales (from ~ 2 to 1000 km2) in a permafrost terrain within a former glacial margin and dominated by relatively inorganic sediments (Peel Plateau, Canada). Our work was conducted along three nested transects with varying intensities of retrogressive thaw slump (RTS) thermokarst activity: a 550 m transect along a first-order thaw stream within a RTS; a 14 km transect along a stream which directly received RTS inputs; and a 70 km transect along a larger stream which received inputs from RTS-affected tributaries. In the thaw stream, rapid sulfuric acid weathering of carbonate tills appeared to amplify CO2 efflux to the atmosphere and HCO3− export downstream, where DIC and CO2 stable isotopes revealed a shift to an abiotic-inorganic driven aquatic carbon cycle. Along the intermediate transect, DIC concentrations were ten times higher in the RTS-affected reach than in the undisturbed headwaters, and decreased downstream with decreasing RTS area. Along the largest transect, HCO3− concentrations increased by two orders of magnitude in association with RTS activity, despite RTSs covering only ~ 0.5 % of the landscape. Statistical modeling of hydrochemical measurements and geospatial landscape data showed that RTSs were a primary landscape driver of HCO3− export across watershed scales. Constraining sources and rates of mineral weathering across diverse permafrost terrains will help to understand future changes in Arctic aquatic carbon cycling, as our results suggest that abiotic-inorganic processes may become prevalent.
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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 | 0.001 |
| 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 | 0.001 |
| 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".