Disease

Why Study Coral Diseases?

Diseases have taken a major toll on the coral population in reefs across the globe. The impact has be exceptionally significant in the Caribbean in which up to 80% of the coral has been decimated.

Coral Disease

Dark Spots Disease (in depth)

• Relevant in the Florida Keys and wider Caribbean
  
• Affected areas are dark purple, gray or brown
• circular or irregular in shape scattered on surface of a colony or at colony's margin
• discolored area increases in size and radiates outward as affected area dies
• Darkened polyps are often depressed and appear smaller in size
• Popular on S. siderea (massive starlet coral), blushing star coral, and M. annularis

Black Band Disease

• Characterized by blackish concentric/crescent-shaped band (given by photosynthetic pigment of the dominant cyanobacteria)
• Consumes live coral tissue as it passes over colony surface
• Caused primarily by cyanobacteria along with sulfide-oxidizing and sulfur-reducing bacteria
• Most commonly affects massive reef-building corals all over the world
• Leaves behind bleached coral

Red band disease

• Narrow bands of filamentous cyanobacteria
• First type, RBD-1, closely resembles BBD except that bands are maroon in color
• Second type, RBD-2, has cyanobacterial filaments spread like a net over colony's surface
• Microbial mat is easily dislodged from surface of coral tissue
• Affects massive and plating stony corals, and also sea fans throughout the wider Caribbean
• Leaves behind bleached coral

White Band Disease

• Extensive occurrence in the Caribbean
• Effects Elkhorn and Staghorn Coral
• Tissue Peels off the coral starting at the base causing thick white bands of bleached coral
• Presumed bacterial infection that affects the Genus Acropora
  • Two types of the disease
• Pathogen unknown but leaves behind brittle coral skeleton
• One of the only diseases known to cause major changes in structural composition of reefs
• After tissue peels away skeleton is weakened by bioerosion

White Pox Disease

• Occurs in the Florida Keys and the Caribbean
• Affects Elkhorn coral
• Causes irregular lesions that leave white patches on coral
• Caused by the pathogen Serratia marcescens
  • Human and animal pathogen
  • Very contagious pathogen that easily spreads to other corals
• Once lesions form algae takes over

Yellow Blotch Disease

• Occurs in the Florida Keys and Caribbean
• Sections of corals become yellowed and translucent
• Cause unknown
• Disease spreads outward and the tissue in the center dies
• Mostly affects large boulder star corals
• Tissue left behind the band are usually covered in coralline algae

References
“Major Reef-building Coral Diseases.” CoRIS - Coral Reef Information System. NOAA, 01-17-13. Web. 2-26-13. <http://coris.noaa.gov/about/diseases/#red band>.
Gochfield, Deborah, Julie Olson, and Marc Slattery. “Colony Versus Population Variation in Susceptibility and Resistance to Dark Spot Syndrome in the Caribbean Coral Siderastrea Siderea.” Diseases of Aquatic Organisms 69 (2006): 53–65. Inter-Research. Web. 02-26-13. <http://www.int-res.com/abstracts/dao/v69/n1/>.
Gil-Agudelo, D.L. and J. Garzón-Ferreira 2001. Spatial and seasonal variation of dark spots disease in coral communities of the Santa Marta area (Columbian Caribbean). Bull Mar. Sci. 69:619-630
Green, E. and A. W. Bruckner. 2000. The significance of coral disease epizootiology for coral reef conservation. Biological Conservation 96:347-361.
Aronson, R. B., Precht, W. F. (2001) “White-band disease and the changing face of Caribbean coral reefs.” Hydrobiologia 460: 25-38.
Kellogg, C. A. “Montastraea cavernosa.” Photo. microbiology.usgs.gov 26 Feb. 2013. < http://microbiology.usgs.gov/image_gallery_plants_animals_montastraea_cavernosa.html>.
“White pox disease in coral caused by human pathogen” (2001). Retrieved 27 Feb. 2013 for < http://www.macroevolution.net/white-pox.html>.
“Coral Diseases” Reef Research Center. Retrieved 26 Feb. 2013 from <http://www.reef.crc.org.au/discover/coralreefs/Coraldisease.htm>

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