EFFECT OF Cr (III) IONS CONCENTRATION ON WAY OF LIFE SPECIFICS, TROPHIC AND DIGESTIVE PARAMETERS OF CERTAIN LIFE FORMS OF POND SNAILS (МOLLUSCA, GASTROPODA, LYMNAEIDAE)

Abstract

For the first time, the influence of Cr (III) ions in maximum concentration limits (MCL) from 0.5 – 3 on the way of life, nutrition and digestion of Lymnaea vulnerata (Küster, 1862) and L. monnardi (Hartmann, 1844), – the different life forms of pond snails of the hydrographic network of Ukraine, – was explored. Due to the long-term natural selection among these species which took place in extremely different ecological environmental conditions, the adaptive radiation of the shell of the ancient original form of pond snail was carried out by rheophilic L. monnardi and stagnophilic L. vulnerata, in opposite directions - divergently. The ampla-shaped shell of L. monnardi (flattened, low, compact, streamlined, with a large mouth) and a large flat sole prevent its drifting by the water current, while the stagnicola-like turret-shape shell of L. vulnerata (elongated, high, narrow, with curls and flat turns, and small mouth) reliably protects it from excessive water consumption in the process of pulmonary respiration, that is important for this ordinary inhabitant of mostly drying out ponds, experiencing conditions of desiccation, which hides in the cracks of drying out bottom.

The autochthonous fodder diet of these pond snails is represented by algae and higher aquatic vegetation (different in species composition for each of the species of mollusks studied).

Under the maximum concentration limits of 0.5, MCL, 2MCL, 3MCL of Cr (III) ions in the environment, a 5-phase process of poisoning is being developed among the pond snails (0.5MCL  - indifference; MCL and 2MCL - stimulation; 3MCL - depressive, sublethal, lethal phases). Its symptoms are clearly illustrated by the values ​​of the main trophological parameters in poisoned individuals, depending on the course of the relevant phases of the pathological process.