Four new corals recorded from Indian waters

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

Source: The Hindu

Previous Year Questions

Q.1) Consider the following statements: (2018)

1. Most of the world’s coral reefs are in tropical waters.
2. More than one-third of the world’s coral reefs are located in the territories of Australia, Indonesia and Philippines.
3. Coral reefs host far more number of animal phyla than those hosted by tropical rainforests.

Which of the statements given above is/are correct?

1. 1 and 2 only
2. 3 only
3. 1 and 3 only
4. 1, 2 and 3