Ontogenic increase of metabolic carbon in freshwater mussel shells (<i>Pyganodon cataracta</i>)
Bibliographic record
Abstract
Incorporation of isotopically light metabolic carbon (CM) can obscure carbon isotope records of dissolved inorganic carbon from biogenic carbonates. Ontogenic increases of CM are common in marine bivalved mollusks, likely reflecting increasing absolute metabolism with increasing body size. Here we use shell aragonite from four specimens of Pyganodon cataracta to test if the same is true in freshwater bivalves. Annual δ18Oaragonite values were not different between individuals suggesting that the aragonite samples represent the same time interval. δ13Caragonite, however, showed an ontogenic decrease, with a strong linear relationship between shell height (H in mm) and %CM (R2 = 0.96; %CM = 0.23*H + 13.33), indicating that more CM is incorporated into larger shells. We estimate that between 15 and 35% of shell carbon is derived from metabolic CO2. Nevertheless, this vital effect does not exclude the use of δ13Caragonite records from freshwater shells as environmental proxies.
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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 | 0.001 |
| 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".