Literaturdatenbank
Literaturdatenbank |
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Jackson, D. C., & Ultsch, G. R. (2010). Physiology of hibernation under the ice by turtles and frogs. Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 313A(5), 311–327.
Added by: Admin (25 Aug 2010 21:58:49 UTC) |
| Resource type: Journal Article DOI: 10.1002/jez.603 BibTeX citation key: Jackson2010 View all bibliographic details  |
Categories: General Keywords: Physiologie = physiology, Schildkröten = turtles + tortoises Creators: Jackson, Ultsch Collection: Journal of Experimental Zoology Part A: Ecological Genetics and Physiology |
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| Abstract |
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Successful overwintering under ice by an air-breathing vertebrate requires either effective aquatic respiration if dissolved O2 is available or the capacity for prolonged anaerobic metabolism if O2 supplies are limiting. Frogs can remain aerobic for many weeks when submerged at low temperature, even at water PO2 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 O2 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 O2. 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.
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