Mobilization of organic carbon and nitrogen in a retrogressive thaw slump on Herschel Island, Yukon Territory, Western Canadian Arctic
Bibliographic record
Abstract
Herschel Island, located in the southern Beaufort Sea, Western Canadian Arctic, shows a \nclear response to the global warming. Due to its ice-rich permafrost it is highly affected \nby environmental forcing and known for its high erosion rates and retrogressive thaw slump \nactivity. Even though retrogressive thaw slumps have an effect on carbon and nitrogen cycling, \nuntil now there is not much known about the processes and carbon and nitrogen availability \nwithin a retrogressive thaw slump at a circumarctic scale. To provide new insides in this \nparticular field, the retrogressive thaw slump “Slump D” on Herschel Island was divided into \nundisturbed (tundra zone, permafrost zone), and disturbed zones (mud pool zone, slump floor \nzone) and sampled via a fishnet grid. The tundra, mud pool and slump floor zones were \nsampled at 0 to 30 cm depth, for the permafrost zone permafrost profiles of up to 340 cm \ndepth were sampled. In total 100 samples were analysed in their biogeochemical parameters \n(total organic carbon(TOC)-, total carbon(TC)-, total nitrogen(TN)-content) and stable isotope \ncontent (δ13Corg). The organic carbon source was determined for all zones to illustrate eventual \ndifferences in the deposition milieu. To show the degree of decomposition and degradation \nduring the slumping process TOC/TN-ratio and δ13Corg were used as proxys. The results show \nthat the tundra zone has the highest TC-, TOC- and TN-values follwed by the permafrost zone. \nThe lowest values are determined for the slump floor and the mud pool zone. All of the zones \nshow similar δ13Corg-values of -26.9‰but obvious differences in the TOC/TN-ratio. From the \nresults it is concluded that the tundra zone shows a higher degradation than the permafrost zone \nbut less than the mud pool and slump floor zone. Based on the high TOC/TN-values for the \npermafrost zone a vulnerable zone where carbon and nitrogen is available for decomposition \nduring thawing processes is indicated. Due to the better quality of the organic matter within \nthe permafrost zone labile carbon can be released right after thawing. The mud pool as well as \nthe slump floor are highly degraded and store the more stable carbon which stays in the soil for \nseveral years. Within the slump floor zone no differences in degradation or composition are \nvisible even though there is a mixture of old and new vegetated areas. With this findings the \nfirst step is made to understand the influence of degrading permafrost on carbon and nitrogen \ndynamics within a retrogressive thaw slump.
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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 | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".