Ecology, Evolution, and Organismal Biology
The goal of this study was to identify the factors that limit the survival of the red-eared slider turtle Trachemys scripta during long-term anoxic submergence at 3°C. We measured blood acid-base status and tissue lactate and glycogen contents after 13, 29, and 44 d of submergence from ventricle, liver, carapace (lactate only), and four skeletal muscles. We also measured plasma Ca2+, Mg2+, Na+, K+, Cl-, inorganic phosphate (Pi), lactate, and glucose. After 44 d, one of the six remaining turtles died, while the other turtles were in poor condition and suffered from a severe acidemia (blood pH = 7.09 from 7.77) caused by lactic acidosis (plasma lactate 91.5 mmol L-1). An initial respiratory acidosis attenuated after 28 d. Lactate rose to similar concentrations in ventricle and skeletal muscle (39.3–46.1 μmol g-1). Liver accumulated the least lactate (21.8 μmol g-1), and carapace accumulated the most lactate (68.9 μmol g-1). Plasma Ca2+ and Mg2+ increased significantly throughout submergence to levels comparable to painted turtles at a similar estimated lactate load. Glycogen depletion was extensive in all tissues tested: by 83% in liver, by 90% in ventricle, and by 62%–88% in muscle. We estimate that the shell buffered 69.1% of the total lactate load, which is comparable to painted turtles. Compared with painted turtles, predive tissue glycogen contents and plasma HCO3- concentrations were low.We believe these differences contribute to the poorer tolerance to long-term anoxic submergence in red-eared slider turtles compared with painted turtles.
Physiological and Biochemical Zoology
Digital Object Identifier (DOI)
Warren DE, Reese SA, Jackson DC. 2006. Tissue glycogen and extracellular buffering limit the survival of red-eared slider turtles during anoxic submergence at 3°C. Physiological & Biochemical Zoology 79(4):736-44.