OPPORTUNISTIC BEHAVIORAL THERMOREGULATION OF TURTLES, PSEUDEMYS SCRIPTA, IN RESPONSE TO MICROCLIMATOLOGY OF A NUCLEAR REACTOR COOLING RESERVOIR

Thermal effluents raised water temperature in one arm of a nuclear reactor cooling reservoir as much as 9 C but had little or no effect on temperature of other areas, or on shoreline microclimate. Pseudemys scripta used an opportunistic strategy of thermoregulation. None resided near the point of thermal discharge. Turtles in heated areas underwent aquatic basking. Body temperatures telemetered from unrestrained turtles were within the preferred temperature range and indicated that aquatic basking raised body temperature 1-3 C above water temperature. In normothermic portions of the reservoir, turtles underwent atmospheric basking on sunny days throughout the year. In summer, basking frequency during the day showed a bimodal curve. Thermoregulatory strategies of these turtles and other turtles from diverse ecological habitats and geographic areas are discussed.