A pigment analysis of feeding modes of <i>Thelepus extensus</i> (Polychaeta, Terebellidae) in relation to wave exposure at the Îles Kerguelen
Bibliographic record
Abstract
Pigment analysis (HPLC and fluorometry) and light microscopy observations of the gut content of Thelepus extensus (Terebellidae) and surrounding sediments were carried out at two hydrodynamically contrasting sites at subantarctic Îles Kerguelen; 1) a sheltered site (Port-Raymond) with a dense population of large-bodied animals, and 2) an exposed site (Port-aux-Français) with a scarce population of smaller individuals. Chlorophyll a derivatives (phaeophorbide a-like) were the most abundant pigments in sediments and polychaete digestive tracts. The second important group of pigments consisted of five unknown carotenoids of which two were present only in the polychaete digestive tract. Pigments in the muddy sediment at the sheltered site appeared to originate from the grazing activity of the polychaetes, as suggested by the high concentrations of degradation products and the same phaeophorbides observed both in the sediment and in the gut contents. Material originating from the dense Macrocystis pyrifera (Phaeophyceae) and Ulvae (Chlorophyceae) cover constituted a large part of the polychaetes' diet at this sheltered site, as indicated by macroalgal debris in the gut contents and the presence of violaxanthin in the sediment and lutein/zeaxanthin in both polychaetes and sediments. The polychaetes seem to adapt their grazing mode to the environmental conditions, preferring suspension feeding in the sheltered site and deposit feeding at the exposed site. The different morphologies, behaviours and life spans of the two conspecific populations may by linked to the contrasting hydrodynamics of the two sites and to their respective diets.
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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".