Symbiotic organisms, called zooxanthellae, or zoox for short, live in tissues of reef-building corals. Corals protect and provide zoox with compounds needed for photosynthesis while zoox provide food as byproduct of photosynthesis to corals for the formation of calcium carbonate skeleton that is the component on which coral reefs are built.
When corals lose their symbiotic zoox, they often become bleached, and in most cases, this leads to death. The loss of zoox is brought about by changes in the environment, such as changes in sea temperature, solar irradiance and sedimentation.
This relationship, however, is not exclusive to all reef-dwelling corals. A recently described agariciid coral, Leptoseris troglodyta n. sp. (Hoeksema, 2012) , found in ceilings and walls of marine caves at depths 5-35 m in the tropical Western Pacific (Philippines, Indonesia, Papua New Guinea, Palau and Guam) does not have zoox characteristic of shallow-water corals. The first of its kind, this coral is described as "azooxanthellate".
Read more about this species here.
|Leptoseris troglodyta Hoeksema, 2012.|
Hoeksema, B.W. 2012. Forever in the dark: the cave-dwelling azooxanthellate reef coral Leptoseris troglodyta sp. n. (Scleractinia, Agariciidae). ZooKeys 228:21-37. doi: 10.3897/zookeys.228.3798