AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 3 626-R632, Copyright © 1991 by American Physiological Society

ARTICLES

Allometry of cooling, supercooling, and freezing in the freeze-tolerant turtle Chrysemys picta

D. L. Claussen and P. A. Zani
Department of Zoology, Miami University, Oxford, Ohio 45056.

Although several vertebrates are freeze tolerant, little is known of the relationship between body size and the kinetics of cooling and freezing. We compared these responses for six hatchling and eight adult Chrysemys picta from an Ohio population. All turtles initially recovered from freezing, and all adults, but only two hatchlings (which experienced ice contents of approximately 35%), exhibited long-term survival. Rapid thawing may have compromised hatchling survival. Turtle water content was inversely related to body mass, but we found no significant correlation between the extent of supercooling and body size. Prefreezing and postfreezing cooling rates scaled with body mass to the -0.55 and -0.40 power, respectively, but the latter rate was more than two orders of magnitude slower. Theoretical (assuming 20% bound water) and calorimetric estimates of body ice agreed reasonably well. Ice contents were both body mass and time dependent. The absolute rate of ice formation scaled with body mass to the 0.4 power. Body size strongly influences the freezing response of ectotherms and deserves more attention.

This article has been cited by other articles:

				Y. Voituron, P. Joly, M. Eugene, and H. Barre Freezing tolerance of the European water frogs: the good, the bad, and the ugly Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2005; 288(6): R1563 - R1570. [Abstract] [Full Text] [PDF]