The physiology of hibernation among painted turtles: the midland painted turtle ( Chrysemys picta marginata)

• Published in: Respiration physiology 2001, Vol.124 (1), p.43-50
• Main Authors: Reese, Scott A., Crocker, Carlos E., Jackson, Donald C., Ultsch, Gordon R.
• Format: Article
• Language: English
• Subjects: Acid-Base Equilibrium; Acidosis - blood; Acid–base, metabolic acidosis; Animals; Anoxia, diving turtles; Biological and medical sciences; Buffer, blood; Calcium - blood; Diving - physiology; Diving, normoxia, hypoxia; Fundamental and applied biological sciences. Psychology; Hematocrit; Hibernation - physiology; Hypoxia - physiopathology; Lactic Acid - blood; Magnesium - blood; Reference Values; Reptiles, turtles; Thermoregulation. Hibernation. Estivation. Ecophysiology and environmental effects; Turtles - physiology; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0034-5687
• DOI: 10.1016/S0034-5687(00)00188-2

Midland painted turtles from Michigan were submerged at 3°C in normoxic and anoxic water. In predive, and in turtles submerged for up to 150 days, plasma PO 2, PCO 2, pH, [Cl −], [Na +], [K +], total Mg, total Ca, lactate, glucose, and osmolality were measured; hematocrit and mass were determined, and plasma [HCO 3 −] was calculated. Anoxic turtles developed a severe metabolic acidosis, accumulating lactate from a predive value of 4.4 mmol/L to a 150-day value of 185 mmol/L, associated with a fall in pH from 7.983 to 7.189. To buffer lactate increase, total calcium and magnesium rose from 3.7 and 2.6 to 58.9 and 11.8 mmol/L, respectively. Plasma [HCO 3 −] was titrated from 39.2 to 4.8 mmol/L in anoxic turtles. Turtles in normoxic water had only minor disturbances of their acid–base and ionic statuses, associated with a much smaller increase of lactate to 23 mmol/L; there was a marked increase in hematocrit from 29.1% to 42.1%. We suggest that it is ecologic, rather than phylogenetic, relationships that determine the responses of painted turtles to prolonged submergence associated with hibernation.