title: The physiology of hibernation among painted turtles: the midland painted turtle (Chrysemys picta marginata).
abstract: Midland painted turtles from Michigan were submerged at 3 degrees C in normoxic and anoxic water. In predive, and in turtles submerged for up to 150 days, plasma PO2, PCO2, pH, [Cl-], [Na+], [K+], total Mg, total Ca, lactate, glucose, and osmolality were measured; hematocrit and mass were determined, and plasma [HCO3-] 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 [HCO3-] 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.
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487-0344, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Reese
authors.forename: C E
authors.initials: CE
authors.lastname: Crocker
authors.forename: D C
authors.initials: DC
authors.lastname: Jackson
authors.forename: G R
authors.initials: GR
authors.lastname: Ultsch
mesh_terms: D000136:Acid-Base Equilibrium; D000138:Acidosis / Q000097:blood; D000818:Animals; D002118:Calcium / Q000097:blood; D004242:Diving / Q000502:physiology; D006400:Hematocrit; D006605:Hibernation / Q000502:physiology*; D000860:Hypoxia / Q000503:physiopathology; D019344:Lactic Acid / Q000097:blood; D008274:Magnesium / Q000097:blood; D012016:Reference Values; D014426:Turtles / Q000502:physiology*
chemical_list: D019344:Lactic Acid; D008274:Magnesium; D002118:Calcium