Coral bleaching observed near Mandapam, Keezhakkarai, Palk Bay
23, May 2019
Prelims level : Mains level :
- The National Centre for Coastal Research, an institute under the Ministry of Earth Sciences, in India, has a field research station in the Gulf of Mannar region, and researchers led by Dr. Shanmugaraj have found an alarming pattern of bleaching in the reefs in Mandapam, Keezhakkarai and Palk Bay.
- They have found that sea surface temperature ranged from 28.7°C to 31°C in the August 2018-February 2019 period and there was no bleaching seen then.
- However, when the temperatures rose to between 32°C and 36°C between March 2019 and May 2019, researchers observed a pattern of bleaching in corals, which was different at different layers within the sea.
- About 12% of coral species observed at depths between 0m and 2m such as Porites solida, Poritis lutea, Montipora digitate, Acropora hyacinthus were completely bleached. About 5% of species observed at depths between 2m and 4m such as Acropora formosa, Acropora hyacinthus, Montipora digitata, Montipora foliosa, Pocillopora damicornis, Goniastrea retiformis, Platygyra sinensis, Dipsastrea favus, Dipsastrea speciosa were partially bleached.
- Porites species observed in Palk Bay region were completely bleached at depths from zero to 4 metres. Corals at depths over 5m did not face bleaching.