A novel culture technique for scleractinian corals:: application to investigate changes in skeletal δ18O as a function of temperature

A novel experimental protocol is described that assists investigations of the effect of environmental parameters on records from the carbonate skeletons of scleractinian corals. It involves the culture of coral colonies on glass slides so as to time the skeletal deposition and environmental records precisely. The value of the technique is demonstrated via calibration of the relationship between skeletal delta(18)O and seawater temperature in 2 species of coral obtained from the Gulf of Aqaba. Colonies were grown at 5 temperatures between 21 and 29 degrees C. For Acropora sp. this relationship gave a slope of -0.27 parts per thousand degrees C-1, a value close to previous estimates. The delta(18)O signature of Stylophora pistillata displayed a high variability between colonies and gave an average slope much lower than previous estimates (-0.13 parts per thousand degrees C-1). These data may indicate a taxonomic difference and the need to re-examine the systematics of this genus. Nevertheless, such variability in colonies of a single species or of a set of closely related species may have implications for the use of coral skeleton as proxy records.