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First published online July 2, 2004
Journal of Experimental Biology 207, 2889-2895 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.01124

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Lactate accumulation, glycogen depletion, and shell composition of hatchling turtles during simulated aquatic hibernation

Scott A. Reese^1,2,*, Gordon R. Ultsch² and Donald C. Jackson¹

¹ Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, Rhode Island, 02912, USA
² Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, 35487, USA

^* Author for correspondence at address 1 (e-mail: scott_reese{at}brown.edu)

Accepted 7 June 2004

We submerged hatchling western painted turtles Chrysemys picta Schneider, snapping turtles Chelydra serpentina L. and map turtles Graptemys geographica Le Sueur in normoxic and anoxic water at 3°C. Periodically, turtles were removed and whole-body [lactate] and [glycogen] were measured along with relative shell mass, shell water, and shell ash. We analyzed the shell for [Na⁺], [K⁺], total calcium, total magnesium, P_i and total CO₂. All three species were able to tolerate long-term submergence in normoxic water without accumulating any lactate, indicating sufficient extrapulmonary O₂ extraction to remain aerobic even after 150 days. Survival in anoxic water was 15 days in map turtles, 30 days in snapping turtles, and 40 days in painted turtles. Survival of hatchlings was only about one third the life of their adult conspecifics in anoxic water. Much of the decrease in survival was attributable to a dramatically lower shell-bone content (44% ash in adult painted turtles vs. 3% ash in hatchlings of all three species) and a smaller buffer content of bone (1.3 mmol g^–1 CO₂ in adult painted turtles vs. 0.13–0.23 mmol g^–1 CO₂ in hatchlings of the three species). The reduced survivability of turtle hatchlings in anoxic water requires that hatchlings either avoid aquatic hibernacula that may become severely hypoxic or anoxic (snapping turtles), or overwinter terrestrially (painted turtles and map turtles).

Key words: hatchling turtle, lactate, buffering, hibernation physiology, anoxia, shell composition