Microbial Controls on Dissolved Organic Nitrogen Cycling During Long‐Term Degradation Experiments
Bibliographic record
Abstract
Abstract Dissolved organic nitrogen (DON) is critical for marine microbial growth by providing carbon and nitrogen. Although DON is rapidly cycled, some compounds within this pool can persist for long‐periods of time. To better understand how DON is cycled by marine microorganisms, we conducted 548‐day incubations using surface‐derived dissolved organic matter along with microbial communities from the surface, mesopelagic, and bathypelagic regions of the Labrador Sea. Across all depths, and even when corrected for particulate production, ∼2 μmol L −1 DON was produced and persisted for several months (i.e., semilabile DON), with ∼20% attributed to cell growth‐and‐death cycles and ∼80% to direct exudation by microbial communities. This newly synthesized DON was subsequently transformed by microbial communities, indicated by increased protein‐like fluorescence and decreased amino acids contribution to DON. These findings suggest that microbial communities can produce transiently persistent DON with potential implications for nitrogen storage and recycling in the ocean's interior.
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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 | 0.001 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.001 | 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 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".