Permafrost Retrogressive Thaw Slump Dissolved Organic Matter Molecular Signatures on the Peel Plateau, Canada
Bibliographic record
Abstract
The Arctic is warming at a rate twice that of other global ecosystems and changing climate conditions in the Arctic are mobilizing long frozen permafrost stores of organic carbon. In regions of extensive ground ice, thawing permafrost can cause land subsidence, and the creation of thermokarst features. The Peel Plateau, Northwest Territories, Canada has extensive thermokarst features exposing early Holocene age paleo-thaw layers and Pleistocene age glaciogenic material deposited by the Laurentide Ice Sheet. This study aimed to see if unique permafrost thermokarst inputs could be readily observed in streams across six diverse thermokarst features via optical and ultrahigh-resolution mass spectrometry. Samples from within thermokarst slump features, and downstream of thermokarst inputs exhibited higher dissolved organic carbon concentrations and lower aromaticity as evidenced by optical parameters (e.g. declining SUVA254, increasing S275-295) and FT-ICR MS metrics (e.g. lower AImod and nominal oxidation state of carbon) versus upstream of thermokarst inputs. Increases in the relative abundances of assigned heteroatomic molecular formulae (e.g. CHON, CHOS, CHONS) were also greater within and downstream of thermokarst features. The unique molecular formulae present in permafrost thermokarst inputs were determined (n=1,844) and subsequently tracked downstream. These permafrost marker formulae were enriched in aliphatics and H/C as well as heteroatoms and exhibited low aromaticity. A portion of the unique molecular signatures persisted downstream, highlighting the potential to not only assess thermokarst inputs but also to follow these inputs and their fate downstream throughout the aquatic network.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.010 | 0.001 |
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".