Stable carbon isotopic analysis of amino acids in a simplified food chain consisting of the green alga <i>Chlorella</i> spp., the calanoid copepod <i>Calanus sinicus</i>, and the Japanese anchovy (<i>Engraulis</i> <i>japonicus</i>)
Bibliographic record
Abstract
Japanese anchovy (Engraulis japonicus Temminck and Schlegel, 1846) is a keystone species in the food web of the Yellow Sea and East China Sea ecosystem. To study nutrient flow at intermediate and lower trophic levels, a controlled feeding experiment was carried out on a simplified food chain of the green alga Chlorella Beijerinck, 1890 – the calanoid copepod Calanus sinicus Brodsky, 1962 – E. japonicus. For the whole organism, bulk δ13C was found to be enriched with escalating trophic level, although the intertrophic gap in δ13C was slightly lower than the commonly reported 1.5‰ per increase in level. Furthermore, 15 amino acids (AAs) were detected in the studied organisms. Among them, the δ13C values of 12 AAs were determined and were found to exhibit diverse patterns of variation. The δ13C levels of essential AAs changed very little and were highly correlated across trophic levels, indicating that they underwent little trophic fractionation and were mainly ingested by the consumers from the proteins in their food. In contrast, the δ13C values of nonessential AAs differed greatly across trophic levels, indicating that the nonessential AAs in consumers were synthesized de novo from food proteins. The fractionation pattern of nonessential AAs may depend on the carbon pool and the AA composition of the organism at the lower trophic level.
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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 | 0.000 | 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) | 0.000 | 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 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".