Aerobic Methanotrophy and Nitrification: Processes and Connections
Bibliographic record
Abstract
Abstract Ammonia and methane are structurally similar molecules. Not surprisingly therefore, microorganisms that use methane as a sole energy source (methanotrophs) and microorganisms that use ammonia as a sole energy source (ammonia oxidisers or nitrifiers) share many similarities. They have several key enzymes in common, most especially the ammonia monooxygenase/particulate methane monooxygenase enzyme family. The two groups are proposed to have a common evolutionary history. They occupy similar ecological niches, and compete for nitrogen. Enzymatically, nitrifiers are capable of methane oxidation, and methanotrophs are capable of nitrification. Microbial ecologists have attempted to find specific inhibitors for either group in order to study their respective roles in the environment. The contribution of ammonia oxidisers to methanotrophy in natural systems appears to be very minor, however methanotrophs may sometimes have important roles in the nitrogen cycle. Key Concepts: Some bacteria and archaea are capable of using methane or ammonia as energy sources. Methanotrophs and ammonia oxidisers are each highly specialised to living on their particular substrate. Methanotrophs and ammonia oxidisers have several key enzymes in common, and may share a common evolutionary history. Both groups must cope with toxic by‐products of ammonia oxidation. Methanotrophs may be important in the environmental nitrogen cycle, but ammonia oxidisers do not affect the methane cycle. Ammonia oxidising archaea appear to outcompete ammonia oxidising bacteria under ammonia‐limiting and acidic conditions.
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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 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".