Impact of some mineral fertilizers on the pulmonary and direct surface respiration of the allospecies of Planorbarius corneus superspecies (Gastropoda: Pulmonata: Planorbidae) from the Ukrainian water bodies

The vicariant genetic allospecies of the superspecies complex of the great ramshorn snail Planorbarius corneus s. lato, “western” and “eastern” – in Right Bank and Left Bank Ukraine, respectively, – are among the widespread and numerous gastropods in the Ukrainian river network. They possess two modes of respiration: pulmonary and surface (diffusive). The gas exchange in these snails is connected to the presence of the respiratory pigment hemoglobin in their internal liquid medium (hemolymph), which transports oxygen in their tissues and organs, and carbon dioxide to the lungs. We studied the features of impact of three mineral fertilizers widespread in Ukraine (nitrate, potassium and phosphate) used in concentrations measured in MPC 0.01 mg/L (0.5, 1, 2, 3) on the indexes of pulmonary and surface diffusive respiration in both P. corneus s. lato allospecies. Exposure of experimental individuals to 0.5 MPC-solutions of mentioned fertilizers does not affect them. The increase of toxicant concentration up to 2 MPC, however, is followed by an increase in respiratory activity (p≤0.05–0.001), but beyond that up to 3 MPC induces a significant decline (p≤0.001). Considered individually, the examined mineral fertilizers presented the following order by their impact on great ramshorns: nitrate > potassium > phosphate. The “eastern” allospecies appeared to be more sensitive and less durable for all aforementioned pollutants by both lung and direct diffusive respiration, compared to the “western” allospecies (p≤0.05–0.001).