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 subtidal habitat, following temperature treatments and transplantation to the intertidal reef zone. 2. Levels of hsp 70 were found to increase markedly in G. dijboutiensis following 2 h heat shocks at 33 degrees C, 36 degrees C, 38 degrees C and 40 degrees C. Transplantation of G. djiboutiensis from the subtidal habitat to the intertidal habitat for 16 and 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 pigment 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 those required to stimulate hsp 70 induction (33 degrees C) in G. djiboutiensis suggests that zooxantheliae may be more thermally sensitive than the host. (C) 1997 Elsevier Science Ltd.