Effect of Elevated Temperature on the Metabolic Activity of the Coral Reef Asteroid Acanthaster planci (L.)

Abstract

Standard rate of oxygen uptake in the coral reef asteroid Acanthaster planci(L.) was determined for the temperature range of 25° to 33° C and a metabolic rate-temperature (M-T) curve was drawn. Acanthaster planci is a metabolic conformer. The rate of oxygen uptake increased with increase of temperature to 31 ° C. The rate decreased at 33° C, which is slightly above the ambient temperature for the laboratory-reared Acanthaster planci tested. The decrease indicates a disturbance in the metabolic activity due to the elevated temperature. The incipient thermal death point for the asteroid was estimated to be near 33° C, at which temperature the animals did not maintain a normal behavior in feeding and resting cycles. Increasing modification in thermal conditions by human activity would pose a hazard to the maintenance of coral reef communities if Acanthaster planci represents metabolic conformer invertebrates with narrow tolerance to elevated temperature.