In News: Scientists have recorded four species of azooxanthellate corals for the first time from Indian waters
These new corals were found from the waters of Andaman and Nicobar Islands.
Azooxanthellate corals are a group of corals that do not contain zooxanthellae and derive nourishment not from the sun but from capturing different forms of plankton.
These groups of corals are deep-sea representatives, with the majority of species reporting from between 200 m to 1000 m.
Their occurrences are also reported from shallow coastal waters. Zooxanthellate corals, meanwhile, are restricted to shallow waters
All the four groups of corals are from the same family Flabellidae.
Truncatoflabellum crassum, T. incrustatum, T. aculeatum and T. irregulare
Under the family Flabellidae were previously found from Japan to the Philippines and Australian waters while only crassum was reported within the range of Indo-West Pacific distribution including the Gulf of Aden and the Persian Gulf.
Azooxanthellate corals are a group of hard corals and the four new records are not only solitary but have a highly compressed skeletal structure.
Hard corals
Hard corals grow in colonies and are often referred to as “reef-building corals.”
Hard corals create skeletons out of calcium carbonate, a hard substance that eventually becomes rock.
Overtime, this rock builds up to form the foundation of a coral reef and provides a structure upon which baby corals can settle.
Hard corals can be further separated into two sub-groups.
Zooxanthellate
The zooxanthellate (reef-building or hermatypic) corals are ones that depend on zooxanthellae algae for nutrients.
These shallow water corals have a major reef-building function.
They are generally found in clear water less than 50 metres deep as the algae need light for photosynthesis.
Azooxanthellate
The azooxanthellate (deep water or ahermatypic) corals do not contain zooxanthellae and therefore gain their nutrition solely from filtering plankton from seawater.
These isolated, solitary or colonial forms rarely build big constructions
