Elucidating trophic pathways of the most abundant fish larvae in northern Patagonia using δ13C and δ15N isotopes
Bibliographic record
Abstract
The alternation of the classic and microbial food-webs in spring and winter, respectively, and the trespass towards higher trophic levels represented by fish early stages, are not well understood in Patagonia. These trophic routes were investigated in the inner Sea of Chiloe, an estuary of high ecological relevance in northern Patagonia. The isotopic values of δ 13 C and δ 15 N of ichthyoplankton and particulate organic matter were analyzed in late winter and spring 2017 to evaluate whether seasonal changes (e.g. in the composition of the freshwater discharge) were reflected in the isotopic signals of fish larvae. For this purpose, larvae of dominant fish species with contrasting feeding strategies were collected up to 100 m depth. The inshore zone of northern Patagonia was characterized by a dominance of marine carbon production, with increasing input of terrestrial organic matter during winter. δ 13 C values < -25 ‰ at the outermost estuary stations indicated the influence of allochthonous carbon exported from the inshore area in spring. The δ 13 C-larval signature of the species of the lightfish Maurolicus parvipinnis , the pipefish Leptonotus blainvilleanus, and the rockfish Sebastes oculatus followed the isotopic signature of the particulate organic matter in both seasons, at inshore and the exchange (outer) zone. Food partitioning was detected between species, with Merluccius spp. at the highest trophic position and L. blainvilleanus at the lowest. The fish larval community reached more diverse and higher δ 15 N values in winter, when larvae likely fed on prey items of higher trophic level, or instead when the food-web was partly sustained by microbial sources. Our results showed seasonal variations in δ 13 C values, suggesting differences in the source of organic carbon incorporated by the studied fish larvae. Moreover, trophic plasticity at larval stages may be an important characteristic of this type of estuarine environment.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".