[Role of carbonic acid in regulation of metabolism and physiological functions in fish].

Experiments with carp showed the metabolic interrelations between exogenic carbonic acid and the fish organism. An increase in the concentration of carbonic acid solved in water causes a rise in its concentration in plasma and a simultaneous compensatory accumulation of HCO3- in blood. When there is a threat of the acidemia development there occurs a rise in the content of bicarbonates in plasma due to the reaction of the carbonic acid hydrogen ions exchange with the blood buffer systems (protein and phosphate ones) accompanied by the compensatory intensification of their reabsorption in the renal tubules and by a total decrease in the intensity of excretion from the kidneys. The dependence of the level of carbonic acid solved in water on its concentration in blood determines the metabolic character of interrelations between the gas regime of water bodies and indexes of their growth and development.