HEAT-SHOCK PROTEIN (HSP-70) EXPRESSION IN THE TROPICAL REEF CORAL GONIOPORA-DJIBOUTIENSIS

1. Heat shock protein 70 (hsp 70) expression has been investigated in a species of tropical reef coral, Goniopora djibouliensis from a subti dal habitat, following temperature treatments and transplantation to t he intertidal reef zone.2. Levels of hsp 70 were found to increase mar kedly in G. dijboutiensis following 2 h heat shocks at 33 degrees C, 3 6 degrees C, 38 degrees C and 40 degrees C. Transplantation of G. djib outiensis from the subtidal habitat to the intertidal habitat for 16 a nd 32 days resulted in elevated constitutive levels of hsp 70 compared with control colonies. 3. Whole organism responses to heat shock were assessed by quantifying zooxanthellae density and the chlorophyll pig ment content of zooxanthellae cells. Heat shock elicited a significant loss of zooxantheliae (p < 0.01). 4. The loss of zooxanthellae from G . djibouliensis at lower heat shock temperatures (30 degrees C) than t hose required to stimulate hsp 70 induction (33 degrees C) in G. djibo utiensis suggests that zooxantheliae may be more thermally sensitive t han the host. (C) 1997 Elsevier Science Ltd.