Respiration and acid-base status of turtles following experimental dives.

JACKSON, DONALD C., AND HELENE SILVERBLATT. Respiration and acid-base status of turtles following experimental dives. Am. J. Physiol. 226(4) : 903-909. 1974.-Freshwater turtles Pseudemys scripta elegans were subjected to experimental dives lasting 24 h at 24°C. Respiratory minute volume and oxygen consumption were measured prior to and for 2-5 h following the dives. Arterial blood samples were taken at intervals before, during, and after the dive and analyzed for pH, Pot, plasma CO2 content, and plasma [lactate]. Pl asma [HCOa-] and Paoos were calculated. The dives caused severe respiratory and lactic acidosis, but 24 h following the dive, normal acid-base status was restored. During the apnea, a significant volume of CO2 was lost from the blood, presumably by diffusion through the body surface. The most notable aspect of the recovery was the hyperventilation which commencedpromptly and restored normal blood pH within 2 h . Higher tha n normal Paz values were attained within 30 min. The recovery of normal [HCOS-] and [lactate] was a much slower process with a half-time of about 3 h. Some lactate was excreted by the kidney, and a small, but insignificant, amount was buffered by the alkaline pericardial and peritoneal fluids.