Interactive effects of copper and calcium in Daphnia pulex
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
<p>Many freshwater habitats around the world suffered dramatic water chemistry changes over the last century mostly due to anthropogenic activities, including an overall reduction in pH due to high sulfur emissions and unsustainable forestry practices. One consequence of this change in water chemistry is a drop in available calcium concentration, which creates problems for aquatic organisms that rely on dissolved calcium to build their exo- or endoskeletons and reinforce their carapace during regular molts. <em>Daphnia</em> populations in shield lakes in northern Ontario are also exposed to other stressors, including copper, which persists at high concentrations in many of these freshwater lakes and ponds due to mining and other human activities. Copper toxicity on animals is influenced by the availability of other competing ions, such as calcium. Using our newly developed high throughput toxicity screening system, we show that mortality of <em>Daphnia pulex</em> increases with exposure to low calcium (0.05 mg L<sup>-1</sup>) and high copper (300 µg L<sup>-1</sup>). When these two stressors were combined, we found that copper was less toxic at high calcium concentrations, indicating a protective effect of calcium against copper toxicity. We then established basic calcium uptake kinetics in <em>D. pulex</em> using radioactive tracer <sub>45</sub>Ca and provide evidence that copper, at environmentally relevant concentrations, competes with calcium uptake based on K<sub>m</sub> and V<sub>max</sub>. Our data show that both calcium decline and copper increase in aquatic ecosystems may negatively impact natural <em>Daphnia</em> populations, and that interactions between these two metals may occur in natural environments that result in fitness consequences for zooplankton. </p>
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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 | 0.000 |
| 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 it