Shifts in dissolved organic matter and nutrients in tundra ponds along a gradient of permafrost erosion
Bibliographic record
Abstract
The accelerated thawing of permafrost in ice-wedge polygonal landscapes results in the formation of shallow ponds, where nutrients and dissolved organic matter (DOM) remain poorly characterized. Over three consecutive summers, water was collected from a series of ponds on degrading syngenetic permafrost, representing the most common geomorphological categories: erosive or stable ice-wedge trough ponds and coalescent polygon ponds. Dissolved organic carbon (DOC) and nutrients were quantified, and DOM was characterized using optical analysis. These ponds were rich in carbon and nutrients, particularly the ice-wedge trough ponds with eroding permafrost. They also exhibited higher concentrations of DOC (+25% on average), total nitrogen (+36%), ammonium (+1164%), and total phosphorus (+108%) in the hypolimnion compared to the epilimnion. DOM was mainly of terrestrial origin (57%–75% of total fluorescent DOM), though protein-like fluorescent components increased in ponds colonized by vegetation and cyanobacterial mats. Weather conditions significantly influenced DOC (+26% in a wet and warm year) and DOM composition in summer, with warmer temperatures and higher precipitation enhancing lateral DOM transfer from permafrost soils and promoting contributions from cyanobacterial mats. These findings improve the understanding of Arctic pond biogeochemistry, enabling a more accurate assessment of their potential role in climate feedback mechanisms.
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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 | 0.001 |
| 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) | 0.001 | 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 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".