Threshold Concentrations of Cations in Environment Determining the Borders of Area of the River Crayfish (Astacus astacus) in Fresh Water Reservoirs
V. I. MARTEMYANOV, A. S. MAVRIN
Papanin Institute of Biology of Inland Waters RASciences, 152742, Yaroslavl Region, Nekouz District, Borok
Keywords: river crayfish, threshold concentration, sodium, potassium, calcium, magnesium
Abstract
The content of sodium, potassium, calcium, magnesium in the haemolymph of the river crayfish caught naturally, was maintained at the levels of 178.0 ± 2.5, 7.1 ± 0.5, 17.3 ± 0.7, 3.0 ± 0.1 mmol/l, respectively. It is shown that the threshold concentrations of sodium, potassium, calcium, magnesium in water, determining the borders of the area of river crayfish in fresh water reservoirs, make 0.0087–0.0174, 0.0046–0.0087, 0.0105–0.0222, 0.0012–0.0033 mmol/l, respectively. Reduction of water mineralization was accompanied by essential increase in the gradients of cation concentrations between an organism and the environment, strengthening the load on the systems of water-salt exchange maintenance. The comparative analysis on the threshold concentration obtained for river crayfish, roach, perch, goldfish, crucian, two species of two-folding molluscs and filamentous alga Spirogyra is carried out.
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