Effects of sublethal copper concentrations, temperature, salinity and oxygen levels on calcium content and on cellular distribution of copper in the gills of Mytilus galloprovincialis lam. A multifactorial experiment

The paper presents the results of a multifactorial experiment performed to evaluate the effects of simultaneous variations of temperature, salinity, oxygen and Cu²⁺, on copper 'metabolism' and calcium content in mussel gills. Our results demonstrate that the factors studied have main and interaction effects not only on the copper level, but also on the ratios between the cytosolic Cu and Cu bound to thioneins, probably resulting in different degrees of toxicity. In addition, it has been shown that the calcium levels are affected by simultaneous variations of the experimental factors. In particular the gills of mussels exposed to Cu²⁺ exhibit a significant increase in calcium concentration, thus indicating that copper may alter Ca²⁺ homeostasis.