Methane-cycling communities in a permafrost-affected soil on Herschel Island, Western Canadian Arctic: active layer profiling of<i>mcrA</i>and<i>pmoA</i>genes
Bibliographic record
Abstract
In Arctic wet tundra, microbial controls on organic matter decomposition are likely to be altered as a result of climatic disruption. Here, we present a study on the activity, diversity and vertical distribution of methane-cycling microbial communities in the active layer of wet polygonal tundra on Herschel Island. We recorded potential methane production rates from 5 to 40 nmol h(-1) g(-1) wet soil at 10 °C and significantly higher methane oxidation rates reaching values of 6-10 μmol h(-1) g(-1) wet soil. Terminal restriction fragment length polymorphism (T-RFLP) and cloning analyses of mcrA and pmoA genes demonstrated that both communities were stratified along the active layer vertical profile. Similar to other wet Arctic tundra, the methanogenic community hosted hydrogenotrophic (Methanobacterium) as well as acetoclastic (Methanosarcina and Methanosaeta) members. A pronounced shift toward a dominance of acetoclastic methanogens was observed in deeper soil layers. In contrast to related circum-Arctic studies, the methane-oxidizing (methanotrophic) community on Herschel Island was dominated by members of the type II group (Methylocystis, Methylosinus, and a cluster related to Methylocapsa). The present study represents the first on methane-cycling communities in the Canadian Western Arctic, thus advancing our understanding of these communities in a changing Arctic.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".