Ionic regulation and shell mineralization in the bivalve<i>Anodonta cygnea</i>(swan mussel) following heavy-metal exposure
Bibliographic record
Abstract
Freshwater mussels are one of the most imperiled faunistic groups in the world and environmental exposure to toxic heavy metals, which result in deregulation of calcium absorption and deposition in the laboratory, may be a contributing factor in their decline. To address potential effects of heavy-metal exposure on calcium transport and metabolism in freshwater bivalves, adult Anodonta cygnea (L., 1758) were exposed to a sublethal concentration (1.0 × 10−6 mol/L) of essential (Zn2+and Cu2+) or nonessential (Pb2+and Cr3+) metal for 30 days in the laboratory. Inorganic composition of extrapallial, haemolymph, heart, and pericardium fluids, and kidney tissue, as well as shell morphology by scanning electron microscopy, were compared in treated and untreated mussels. Calcium levels in fluids varied after exposure to any of the metals investigated, although the magnitude and threshold of effect were metal- and compartment-specific. Ca2+levels increased robustly in all fluids following exposure to Zn2+, Cu2+, or Cr3+, whereas levels decreased significantly in heart fluid alone following Pb2+exposure (p < 0.05). In constrast to exposure to the other metals, Cu2+revealed an interesting reverse-accumulation pattern, decreasing in the fluids but not in the kidney, where it clearly accumulates for excretion. In addition, whereas essential Cu2+and Zn2+are closely regulated, the nonessential metals Pb2+and Cr3+increase to very high levels. Drastic alterations in shell morphology, specifically the structure of border and inner pallial regions of the nacreous layer, were observed after Cu2+or Cr3+exposure. Collectively, data suggest that prolonged exposure to a sublethal concentration of these heavy metals can adversely affect compartmental calcium availability and shell composition in A. cygnea.
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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".