Impact of aquatic habitat environment on the elemental composition and shell shape variability of the Beringian freshwater mussel Beringiana beringiana (Bivalvia, Unionidae)

Concentrations of the chemical elements were analyzed in the shells of a bivalve mollusk species (Beringiana beringiana), water, and bottom sediments from seven lakes located on the Kamchatka Peninsula, the Kurile Islands, Sakhalin Island, and Primorsky Krai (Northeast Asia). A principal component analysis allowed to determine three factors those were related to environments in the waterbodies. We revealed two groups of samples corresponding to large geographical regions using the determined factors. Statistically significant differences were found between geographical groups of samples, and higher values of element distribution coefficients were determined for samples from lakes on the Kamchatka Peninsula. The highest concentrations of lithophilic elements were measured in the shells from Lake Kurazhechnoye (Kamchatka Peninsula). The highest concentrations of Al and Mg were detected in shells from Lake Peschanoye (Kunashir Island). In Lake Chernoye (Sakhalin Island), the highest concentrations of Sr and Sb in the shells were detected. Zn, Fe, Pb, and rare earth elements were present in large concentrations in the shells from Lake Vaskovskoye, Primorsky Krai. The shells of the Beringian freshwater mussel show large phenotypic plasticity, and their shape demonstrates significant relationships with various environmental parameters, that were assessed based on the geochemical indicators.