Blood viscosity and hematological changes during prolonged submergence in normoxic water of northern and southern musk turtles (Sternotherus odoratus)

Abstract

Musk turtles (Sternotherus odoratus) can survive at least 150 days of submergence in normoxic water at 3°C, during which time there are large increases in packed cell volume (PCV). We investigated the effects of submergence in normoxic water at 3°C on the blood viscosity of musk turtles from northern (Massachusetts) and southern (Alabama) locales. Blood was collected from air‐breathing turtles and after 20, 50, 100, and 150 days of submergence in normoxic water at 3°C. Hematological responses to submergence were similar in the two groups, therefore the results were combined. Packed cell volume increased steadily above that of controls after 20, 50, 100, and 150 days of submergence. Hemoglobin concentration also progressively increased above that of controls after 20, 50, and 100 days of submergence but declined to near control values after 150 days. Blood viscosity increased with increasing PCV; however, blood viscosity of musk turtles appears less affected by PCV than is blood viscosity of mammalian species. As such, musk turtles appear to be able to maintain adequate blood flow to tissues while increasing the oxygen carrying capacity of the blood during prolonged submergence. However, after 150 days submergence, oxygen delivery should decrease due to a reduced oxygen carrying capacity of the blood and an increased resistance to blood flow, which may limit the length of time these turtles can remain viable during hibernation. J. Exp. Zool. 287:459–466, 2000. © 2000 Wiley‐Liss, Inc.

Hemorheology and oxygen transport in vertebrates. A role in thermoregulation?

“…Although some authors have also described an optimal adjustment of erythrocyte rheological properties at physiological temperatures in different vertebrate species (9,11,15,4,20), the mechanisms underlying these responses are still not clear. Moreover, there is no agreement in the interpretation and physiological meaning of the blood viscosity differences observed at low temperature between temperate and Antarctic species (6,3,21). Changes in blood viscosity induced by environmental temperature have been postulated as a dominant factor affecting heat exchange, by modifying peripheral blood flow, in heterothermic species (9).…”

Survival and Physiological Responses of Hatchling Blanding’s Turtles (Emydoidea blandingii) to Submergence in Normoxic and Hypoxic Water under Simulated Winter Conditions

“…The turtles did not appear to have been under physiological stress because total magnesium was the only measured variable that changed during 75 d of submergence. The mortality we observed may ultimately prove to be an artifact, given that the hatchlings (Reese et al 2002a) and adults (Ultsch 1985(Ultsch , 1988Saunders et al 2000;Reese et al 2001) of various species readily survive submergence in cold, normoxic water for at least 150 d.…”

“…Like C. serpentina, hatchling Apalone spinifera accumulated a small quantity of lactate, although it is doubtful that this change represents a reliance on anaerobic metabolism. Hematocrit increased in these turtles, perhaps functioning to improve oxygen carrying capacity (Saunders et al 2000).…”

The Fish in the Turtle: On the Functionality of the Oropharynx in the Common Musk Turtle Sternotherus odoratus (Chelonia, Kinosternidae) Concerning Feeding and Underwater Respiration

“…Another goal of this study is therefore to search for oropharyngeal organs that are potentially responsible for aquatic gas exchange by using scanning electron microscopy (SEM) and histological methods. The capability of S. odoratus to remain submerged for prolonged periods has been the object of many physiological studies (see Saunders et al, 2000 for overview). According to Root (1949), Pritchard (1979), and Stone et al (1992), common musk turtles mainly use their papillous skin for oxygen uptake, when submerged.…”