Early spring population dynamics of Salpa thompsoni linked to physical oceanography in the Atlantic sector of the Southern Ocean
Bibliographic record
Abstract
Abstract The pelagic tunicate Salpa thompsoni accounts for a large portion of the zooplankton in the Southern Ocean. While salp’s functional role in pelagic ecosystems is recognised, their life cycle during winter and spring remains poorly understood. To uncover the effects of environmental drivers on S. thompsoni population dynamics, we collected physical oceanography and salp population development data in the Atlantic sector of the Southern Ocean during the spring of 2022. Salp abundances were generally < 5 ind. m− 2 in the 0–150 m and 0–600 m layers. The S. thompsoni population was at the most advanced stages of development, including a diverse stage composition and a bimodal size distribution, in the sub-Antarctic Zone north of the Polar Front (PF). This indicated ongoing salp reproduction that started at least one month prior to our voyage. Stations located in the Antarctic Zone south of the PF were characterised by low salp densities (generally < 2 ind. m− 2) and early developmental stages. The distribution of biologically diverse salp populations and their development were strongly influenced by the regional physical oceanography. The region’s strong currents and dynamic frontal systems, including eddies emerged as a major driver of salp population dynamics. The findings from this study illustrate that salps north of the PF likely spawn year-round, while their populations in regions influenced by Antarctic waters show strong seasonal development and their reproduction may seize during the austral winter.
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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 | 0.001 |
| 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 | 0.000 | 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".