Jokiel,-P.L.; Coles,-S.L.  Response of Hawaiian and other 
	Indo-Pacific reef corals to elevated temperature.  
	CORAL-REEFS. 1990. vol. 8, no. 4, pp. 155-162.

Loss of symbiotic zooxanthellae, or "bleaching" is one of the 
first visible signs of thermal stress. Bleaching can be 
induced by short-term exposure (i.e. 1-2 days) at temperature 
elevations of 3 degree C to 4 degree C above normal summer 
ambient or by long term exposure (i.e. several weeks) at 
elevations of 1 degree C to 2 degree C. Corals in both 
tropical and subtropical locations live at temperatures close 
to their lethal limits during the summer months. Temperature 
elevations above summer ambient, but still below the 
bleaching threshold, can impair growth and reproduction. A 
warming trend in Hawaiian waters has been observed over the 
past decade. In 1986, 1987 and 1988 Hawaiian corals were 
perilously close to their bleaching threshold during the 
summer months, and localized bleachings did occur. In some 
cases, local warming of surface water on shallow reef flats 
exceed this threshold temperature and caused localized coral 
bleaching. A continuation of the warming trend in Hawaii 
would lead to mass bleachings similar to those observed 
recently in other geographic locations.