Like all marine organisms, coral too are susceptible to a wide variety of diseases caused due to changes in water conditions, stress, bacteria, viruses and parasites often resulting in the deterioration or even death of the coral. In some severe cases, diseases such as coral bleaching and White Band disease have been known to destroy entire reef ecosystems wiping out kilometers of coral in its wake. There are numerous known conditions and diseases that affect coral, though not a lot known on what causes or how to treat such outbreaks. A few of the more common coral conditions we have described below.
Coral Bleaching
Coral Bleaching is a coral condition that is making nations around the world sit up and take notice of pollution and global warming. Coral Bleaching is the whitening of coral caused by stress-induced ejection of the symbiotic algae that normally produces food for the coral. This expulsion of the vital protozoa makes coral appear bleached and ultimately kills the coral. While coral bleaching is not truly a disease scientists say that increased ocean temperatures caused by Global warming is bleaching massive reefs around the world and weakens the corals resistance causing coral to be open to attack from other diseases.
Black Band Disease
Is a pathogen that infects coral tissue appearing as a dark blackish-brown band that progressivley moves across the healthy coral at a few millimeters a day causing tissue death. The coral in front of the black band is healthy while the part of the coral behind the band is dead. Black Band disease is thought to be associated with cynobacteria and is known to affect around 42 species of coral worldwide.
White Band Disease
Also known as the white syndrome which results in the formation of white bands, spots or patches in the healthy coral known to affect only staghorn and elkhorn coral. This disease is characterized by tissue that peels off the coral in uniform bands beginning at its base and moving upwards to its tips gradually killing off the coral, leaving the coral bleached and dead. The causes of white syndrome are as yet unknown, but it effects are causing major plague like proportions to the Caribbean reefs decimating huge areas of coral reef and communities.
Skeletal Eroding Band
Is a disease that looks similar to Black Band Disease as a dark grey or black band appears on the coral which slowly advances leaving a spotted region of dead coral in its wake. This disease is known to be caused by a protozoan (a single celled organism covered in hairs) which divides drilling into the coral’s limestone skeleton killing the coral polyps in the process. Skeletal Eroding Band disease is common in the Indian and Pacific oceans and also in the Red Sea.
White Pox Disease
White Pox Disease also known as patchy necrosis is known to affects coral reefs around the Florida Keys and the Caribbean mainly effecting Elkhorn Coral characterized by circular lesions. The disease caused by a bacteria, causes white blotchy patches to appear on the coral that result in the loss of tissue.
photos from flickr by: mattk1979, spiderman (Frank), jkirkhart35
