Trophic characteristics of Lymnaea stagnalis (Mollusca: Gastropoda: Lymnaeidae) in toxic environment

Abstract

The influence of ions of heavy metals (copper, cadmium, nickel, zinc, cobalt and manganese) was investigated on the basis of trophic characteristics: the average daily ration (ADR), and duration of food passage (DFP) of the Lymnaea stagnalis L. in various concentrations of toxicants in vivisection experiment. In addition to these indicators, the total amount of food consumed in the solutions with various concentrations of pollutants was found out during the chronic experiment and it was calculated for an individual (average monthly ration – AMR). It leads to the conclusions about the intensity of food consuming considering different levels of intoxication. In solutions with lethal concentrations, the death of animals occurs during the first day of its impact due to the damage of tissues and organ systems. Chronic lethal concentrations of toxicants inhibit the nutrition of pond snails dramatically. At the beginning of the experiment, solutions of heavy metals with sublethal concentrations give some stimulatory effect on the digestive system of molluscs that is replaced by its suppression in case of longer being in the toxic environment. The influence of toxicants within a subthreshold limit cannot be considered safe because of the cumulative properties of heavy metals – they become sublethal with prolonged exposure time.

The growth characteristics and survival rates of great pond snail (Lymnaea stagnalis L.) juvenile under the heavy metal impact

“…The presence of juveniles in solutions of chronic lethal concentrations of heavy metals leads to persistent suppression of their viability, which is manifested in high values of snails' death. At the same time, a paradoxical situation arises: juveniles react less strongly to those metals that were diagnosed as highly toxic in the acute experiment and more strongly to those that were determined to be slightly toxic [3]. Thus, in solutions of chronic lethal concentrations of Co 2+ and Mn 2+ , up to 80-90% of juveniles die (figure 4).…”

“…In recent decades, anthropogenic factors have accelerated the cycle of geochemical elements, resulting in increasing metal imports into water systems [1,2]. The heavy metals such as Copper (Cu), Cadmium (Cd), Zink (Zn), Cobalt (Co), Manganese (Mn), and Nickel (Ni) are potentially hazardous in combined or elemental forms [3,4]. Most are on the U.S. Environmental Protection Agency's list of priority metals for monitoring and assessing their harmful effects on aquatic ecosystems [5][6][7][8].…”

Spatial Organization of the Micromollusc Community under Recreational Load

“…The ecological factors influencing the distribution of species are usually spatially structured, so the species community also has a spatial structure (Andrushenko and Zhukov, 2016;Pinkina et al, 2019;Thuiller et al, 2004;Zhukov et al, 2015). The micromollusc community in the park plantation in the city of Melitopol is represented by three species, among which Vallonia pulchella significantly dominates, Cochlicopa lubrica is significantly less abundant and Acanthinula aculeata almost 10 times less abundant.…”

Spatial Organization of the Micromollusc Community under Recreational Load

“…The ecological factors influencing the distribution of species are usually spatially structured, so the species community also has a spatial structure (Andrushenko and Zhukov, 2016;Pinkina et al, 2019;Thuiller et al, 2004;Zhukov et al, 2015). The micromollusc community in the park plantation in the city of Melitopol is represented by three species, among which Vallonia pulchella significantly dominates, Cochlicopa lubrica is significantly less abundant and Acanthinula aculeata almost 10 times less abundant.…”