A novel culture technique for scleractinian corals: application to investigate changes in skeletal delta O-18 as a function of temperature

A novel experimental protocol is described that assists investigations of t he effect of environmental parameters on records from the carbonate skeleto ns of scleractinian corals. It involves the culture of coral colonies on gl ass slides so as to time the skeletal deposition and environmental records precisely. The value of the technique is demonstrated via calibration of th e relationship between skeletal delta(18)O and seawater temperature in 2 sp ecies of coral obtained from the Gulf of Aqaba. Colonies were grown at 5 te mperatures 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 prev ious estimates. The delta(18)O signature of Stylophora pistillata displayed a high variability between colonies and gave an average slope much lower t han previous estimates (-0.13 parts per thousand degrees C-1). These data m ay indicate a taxonomic difference and the need to re-examine the systemati cs of this genus. Nevertheless, such variability in colonies of a single sp ecies or of a set of closely related species may have implications for the use of coral skeleton as proxy records.