Effects of Oxygen on Denitrification Inhibition, Repression, and Derepression in Soil Columns
Bibliographic record
Abstract
Although it is known that O 2 inhibits and represses denitrification, few studies have examined the effect of O 2 on NO production. Our objectives were to measure O 2 inhibition, repression, and derepression of NO and N 2 O production by denitrifying microorganisms in soil columns continuously purged by N 2 or various constant (0.074–15%) O 2 –N 2 mixtures. Net rates of NO and N 2 O production were measured under successive anaerobic, partially aerobic, and anaerobic conditions. Oxygen inhibition was rapid and reversible. Within 5 min after exposure to >5% O 2 , NO production was reduced to ≈50 to 58% and N 2 O rates to ≈29 to 32% of their maximum anaerobic rates. Maintaining O 2 at ≥5% in soil without added C or at >10% O 2 in C‐amended soil decreased (repressed) NO production rates by a factor of ≈1.5 to 1.8 d −1 Rates of N 2 O repression remained constant at ≈0.07 d −1 for all C and O 2 treatments. Restoration of anoxic conditions following the aerobic phase reversed inhibition; within 5 min, NO production rates by the nonrepressed denitrifiers increased to 55 to 101% of their respective anaerobic rates and N 2 O production rates increased to 26 to 62%. The rates of NO and N 2 O production then increased more slowly (derepression) during this anaerobic period. This research supports previous observations for O 2 effects on N 2 O production and apparently is the first systematic study of O 2 inhibition, repression, and derepression of NO production.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".