|Observations on zooxanthellae expulsion at Middle Sambo Reef, Florida Keys|
Jaap, W.C. (1979). Observations on zooxanthellae expulsion at Middle Sambo Reef, Florida Keys. Bull. Mar. Sci. 29(3): 414-422
In: Bulletin of Marine Science. University of Miami Press: Coral Gables. ISSN 0007-4977; e-ISSN 1553-6955, meer
Environmental effects > Temperature effects
Interspecific relationships > Symbiosis
Reefs > Biogenic deposits > Coral reefs
Corallinaceae Lamouroux, 1812 [WoRMS]
Large-scale discoloration of Middle Sambo reef, 7.8 km from Boca Chica Key, Monroe County, Florida, was investigated on Sep 26, 1973. Discoloration of organisms was generally confined to the reef flat. The hydrozoan coral Millepora complanata displayed greatest discoloration. Some Acropora palmata, Montastraea annularis and Palythoa sp colonies were midly discoloured. Corals were still viable. Calm weather, high ambient temperatures, and low tides at midday are believed to have caused water temperature elevation sufficient to produce thermal stress, thereby causing expulsion of endosymbiotic algae, Gymnodinium microadriaticum, with consequent discoloration of cnidarian hosts. Most organisms regained normal color within 6 weeks. Reports of similar coral discoloraton incidents are reviewed. Short periods of thermal stress appear to have little lasting effect on shallow reef cnidarian communities.