From UPSC perspective, the following things are important :
Prelims level : Corals, Coral Bleaching
Mains level : Not Much
Scientists have recorded four species of corals for the first time from Indian waters. These new species of azooxanthellate corals were found from the waters off the Andaman and Nicobar Islands.
What are Azooxanthellate Corals?
- The 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 planktons.
- They are deep-sea representatives with the majority of species being reported from depths between 200 metres and 1,000 metres.
- They are also reported from shallow waters unlike zooxanthellate corals that are restricted to shallow waters.
Which are the news species found?
- Truncatoflabellum crassum, T. incrustatum, T. aculeatum, and T. irregulare under the family Flabellidae were previously found in Japan, the Philippines and Australian waters.
- Only T. crassum was reported with the range of Indo-West Pacific distribution.
Significance of the discovery
- Most studies of hard corals in India have been concentrated on reef-building corals while much is not known about non-reef-building corals.
- These new species enhance our knowledge about non-reef-building solitary corals.
Back2Basics: Coral Reefs
- Corals are marine invertebrates or animals not possessing a spine.
- Each coral is called a polyp and thousands of such polyps live together to form a colony, which grows when polyps multiply to make copies of themselves.
- Australia’s Great Barrier Reef is the world’s largest reef system stretching across 2,300 km.
- It hosts 400 different types of coral, gives shelter to 1,500 species of fish and 4,000 types of mollusc.
- Corals are of two types — hard coral and soft coral:
- Hard corals, also called hermatypic or ‘reef building’ corals extract calcium carbonate (also found in limestone) from the seawater to build hard, white coral exoskeletons.
- Soft coral polyps, however, borrow their appearance from plants, attach themselves to such skeletons and older skeletons built by their ancestors. Soft corals also add their own skeletons to the hard structure over the years and these growing multiplying structures gradually form coral reefs. They are the largest living structures on the planet.
How do they feed themselves?
- Corals share a symbiotic relationship with single-celled algae called zooxanthellae.
- The algae provides the coral with food and nutrients, which they make through photosynthesis, using the sun’s light.
- In turn, the corals give the algae a home and key nutrients.
- The zooxanthellae also give corals their bright colour.