Open AccessPhysiology of hibernation under the ice by turtles and frogs
Author(s) -
Jackson Donald C.,
Ultsch Gordon R.
Publication year - 2010
Publication title -
journal of experimental zoology part a: ecological genetics and physiology
Language(s) - English
Resource type - Journals
eISSN - 1932-5231
pISSN - 1932-5223
DOI - 10.1002/jez.603
Subject(s) - biology , hibernation (computing) , painted turtle , turtle (robot) , glycogen , respiration , anoxic waters , limiting , anaerobic exercise , ecology , overwintering , chelydra , zoology , botany , physiology , biochemistry , mechanical engineering , state (computer science) , algorithm , computer science , engineering
Successful overwintering under ice by an air‐breathing vertebrate requires either effective aquatic respiration if dissolved O 2 is available or the capacity for prolonged anaerobic metabolism if O 2 supplies are limiting. Frogs can remain aerobic for many weeks when submerged at low temperature, even at water PO 2 as low as 30 mmHg, but are unable to survive even 1 week in anoxic water. Fuel reserves of hibernating frogs limit aerobic submergence, whereas acidosis may limit anoxic submergence. Freshwater turtles can also satisfy all or most of their O 2 needs in well‐aerated water at low temperature by aquatic respiration, but certain species, in particular painted and snapping turtles, can also survive for up to 4–5 months without O 2 . Key adaptations of the painted turtles, and presumably snapping turtles, include metabolic depression and the exploitation of the shell and other bones to buffer lactic acid. As in frogs, glycogen and glucose are the only fuel sources during anoxia, and stores do not seem to be limiting in the painted turtle. Significant differences in anoxia tolerance exist among chelonian species that can be attributed, at least in part, to the magnitude of metabolic depression, the effectiveness of lactic acid buffering, and the size of glycogen stores. J. Exp. Zool. 313A:311–327, 2010 . © 2010 Wiley‐Liss, Inc.