Mixed photosynthetic-chemosynthetic diets in vent obligate macroinvertebrates at shallow hydrothermal vents on Volcano 1, South Tonga Arc - evidence from stable isotope and fatty acid analyses
Bibliographic record
Abstract
Several submerged, hydrothermally active arc volcanoes in the southern and western Pacific Ocean rise to photic zone depths. These settings provide an opportunity to investigate the trophic ecology of vent-obligate species in a non-coastal, shallow-water context where both chemosynthetic and photosynthetic carbon sources are present. We report here on a stable isotope and lipid biomarker study of food web relationships in hydrothermal vent communities on Volcano 1, located along the southern Tonga Arc, in the southwestern Pacific. Active venting and vent communities were found at two locations in the photic zone (100 m depth) and at a 200 m deep site. All three locations were colonized by bathymodiolan mussels. Hydrothermal vent limpets (Shinkailepas sp. and Lepetodrilus sp.) were also sampled at these sites together with the vent crab Xenograpsus ngatama. Our collections of Bathymodiolus sp., Shinkailepas sp., and Lepetodrilus sp. at the two 100 m deep sites represent the shallowest known occurrences for these vent-endemic genera. Filamentous green algae were found in limpet guts and growing on rock and other surfaces at the photic zone sites. Stable isotope and lipid results indicated that crab and limpet species at the photic zone sites had a mixed diet of photosynthetic and chemosynthetic food sources, while specimens from 200 m relied on chemosynthetic material only. Even the symbiont-containing mussels from the shallower sites had stronger (albeit minor) photosynthetic signatures than did mussels from 200 m. The oceanic location of these photic zone vents may be a factor in explaining the presence of vent-obligate species, since coastal vent systems typically lack vent endemic metazoans. We predict that other studies of photic zone vents in volcanic arc settings will find communities of vent, and possibly non-vent, species exploiting mixed photosynthetic-chemosynthetic 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 | 0.001 | 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".