Kuroshio Shape Composition and Distribution of Filamentous Diazotrophs in the East China Sea and Southern Yellow Sea
Bibliographic record
Abstract
Abstract The filamentous Trichodesmium and Richelia/Calothrix appear to be crucial N2‐fixing cyanobacteria throughout the warm oligotrophic ocean, particularly in western boundary currents. The Kuroshio, the hotspot of N2 fixation in the Pacific Ocean, intrudes into the East China Sea (ECS) and southern Yellow Sea (SYS), which may profoundly influence composition and distribution of filamentous diazotrophs. We provide high spatial resolution dataset of filamentous diazotrophs in the ECS and SYS in July and August 2013. Results showed that Trichodesmium colonies and Richelia/Calothrix were strictly restricted to warm, saline, nitrogen‐limited waters of the ECS influenced by Kuroshio and were not detected in the SYS. The density of Trichodesmium in the ECS and SYS was 8.48 × 106 trichomes/m2, and colonial trichomes accounted for 40%. In addition to free filaments, Richelia/Calothrix were found to be symbiotic with diatoms Hemiaulus, Rhizosolenia/Guinardia, Chaetoceros, and Bacteriastrum with a total density at 2.13 × 106 heterocysts/m2 in the ECS. The densities of filamentous diazotrophs were significantly higher in high‐salinity region of the ECS (mainly controlled by Kuroshio) than in low‐salinity region of the ECS and in the SYS. The densities of Trichodesmium and Richelia/Calothrix were significantly and positively correlated with temperature, salinity, and mixed‐layer depth but were negatively correlated with NO3, turbidity, and chlorophyll‐a. These results suggested that composition and distribution of filamentous diazotrophs in the ECS and SYS were largely shaped by Kuroshio and associated physicochemical properties. We hypothesize that active N2 fixation in Kuroshio may be substantially supported by Richelia/Calothrix in addition to Trichodesmium.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".