[Coral-List] Survival of corals without zooxanthellae

Gene Shinn eshinn at usgs.gov
Tue Jan 11 13:43:13 EST 2005

I observed warm-water-induced bleaching during a coral transplant 
study  in 1961 ( Shinn 1966). Acropora cervicornis was transplanted 
from the outer reef to a location in 1.5 m water depth near the Key 
Largo shoreline  where the species does not live.  The transplant 
grew  at the same  rate as the offshore parent colony for 3 months 
in the spring when temperatures were in the same range as offshore. 
In mid and late summer when shallow water temperature exceeded 33 
degrees the  branches expelled zooxanthellae  (the term bleaching was 
not in use then) and growth rate diminished sharply relative to the 
parent colony  8 km offshore.  When temperatures dropped in the fall, 
color returned and growth rate increased until  late December. 
However,by February, 1962,  a series of cold fronts had lowered near 
shore water temperatures to 13.5 degrees C. and the coral  died. 
Because growth measurements and temperature, from maximum minium 
thermometers, were made monthly  it is impossible to say exactly how 
long the corals lived with reduced zooxanthellae but it is safe to 
say it was at least 2 months.
Shinn E. A., 1966, Coral growth rate, an environmental indicator. 
Journal of Paleontology, v. 40 pp. 233-240.

No Rocks, No Water, No Ecosystem (EAS)
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E. A. Shinn
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USGS Center for Coastal Geology     |
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