Latitudinal and vertical distributions of particle-associated dimethylsulfoniopropionate (DMSP) lyase activity in the western North Atlantic Ocean
Bibliographic record
Abstract
Dimethylsulfoniopropionate (DMSP) lyase enzymes cleave phytoplankton-derived DMSP into dimethylsulfide (DMS) and acrylate. We measured particle-associated (>0.7 µm) DMSP lyase activity (DLA) in diverse waters from the Gulf of Maine to the Sargasso Sea. DLA fell within a relatively narrow range (0.635.4 nmol DMS·L1·min1), with no significant geographic trend. DLA was, however, generally highest near the surface and decreased with depth within the euphotic zone. When normalized to chlorophyll a (Chl a), DLA was significantly higher in oligotrophic surface waters of the Sargasso Sea (DLA:Chl a = 3353 nmol DMS·min1·µg Chl a1) compared with more productive Gulf of Maine waters (DLA:Chl a = 0.57.9 nmol DMS·min1·µg Chl a1). In optically clear waters of the Sargasso Sea, DLA:Chl a was generally highest near the surface and decreased with depth, following a similar trend to that of the photoprotective pigment diadinoxanthin. When ammonium and phosphate were added to oligotrophic water from the Sargasso Sea, Chl a increased exponentially, whereas DLA:Chl a decreased by 83%. Our results suggest that Chl a specific DLA is highest when plankton are exposed to high solar radiation and low nutrients, consistent with the idea that DMSP lyases may be involved in oxidative stress protection.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".