Features of the change of metabolism in Cladocera Moina micrura under adaptation to hypoxia

The effect of hypoxia on total and basal metabolisms was investigated in active and narcotized females of Moina micrura. The experimental animals were brought from two laboratory cultures, reared under the conditions of normal and low (1.0 mg O2/l) oxygen concentrations at 18 °C. It was shown that, on the level of basal metabolism, acclimated to hypoxia and nonacclimated animals perform the same excretion ”dependent” of respiration and ammonia. The O : N ratio ranges from 8.5 at sharp hypoxia to 34-40 under conditions of oxygen saturation. For total metabolism, the rates of respiration and excretion of nonacclimated and acclimated females decline due to a decrease of the oxygen content. Oxygen consumption in acclimated "red” (with increased content of hemoglobin) animals was 6 times higher than in nonacclimated ones. The O : N ratio for both groups of animals changed from 5-7 to 24 proportionally to the oxygen content. In the scope of activity, the O : N ratio in acclimated Moina varies from 14 to 23 independently of the oxygen concentration. The ability to maintain a relatively high level of metabolism for a sufficient locomotive activity is the main way of the adaptation to hypoxia in Moina micrura