Temperature Effects on the Responses to Prolonged Submergence in the Turtle Chrysemys picta bellii. I. Blood Acid-Base and Ionic Changes during and following Anoxic Submergence

• DOI: 10.1086/physzool.58.6.30156070
• Publication Date: 2016-01-07T15:59:47Z
• Authors: Christine V. Herbert; Donald C. Jackson
• Keywords: pCO2; Acid–base homeostasis; Respiratory acidosis; Plasma osmolality; Acid–base reaction; Blood plasma

Blood acid-base status and plasma ion concentrations osmolality of freshwater turtles (Chrysemys picta bellii) were measured periodically during following submergence in N₂-equilibrated water (Po₂ < 5 torr) at 3, 10, 15, 20 C. Submergence durations that resulted similar reductions blood pH or [HCO₃⁻] each temperature 12 h C, 3 days 15 10 13 wk At 75% the fall anoxia was due to metabolic acidosis, but contribution respiratory acidosis drop increased with temperature, being 50% 73% Plasma strong-ion difference decreased much less than had been predicted on basis increase lactate, owing compensatory changes ions, including [K⁺], total [Ca⁺⁺], [Mg⁺⁺] [Cl⁻]. The magnitude these directly correlated which turn inversely temperature. lactate ranged from 96 mM C 19.7 Recovery anoxic all temperatures occurred two stages, a stage rapidly restored lowered PCo2 below control values slower ionic corrected associated disturbances other ions. anoxia, extent varied as did net We conclude prolonged tolerance is not specialized mechanisms absent higher temperatures; rather, slow accumulation modest hypercapnia, effective markedly retard development this