Coral Bleaching

Causes and Consequences

A CASE STUDY OF ANDAMAN AND NICOBAR ISLAND

What is Coral ?

Tiny organism belonging to

group anthozoa of

phylum Cnidaria

Secrets a massive

calcareous skeleton and collectively

deposits calcium carbonate to build colonies

Hard corals harbor an

algae called “Zooxanthallae

”

Pigment of this algae gives

extensive color to coral tissue

Coral Polyps

Corals consists of

small polyps living

together in a group or colony

A single polyp has

tube shaped body with a

mouth surrounded by tentacles

Tentacles helps in

capturing prey for feeding

During daytime

polyps are withdrawn in

their skeletons

At night polyps

protrude out for feeding

What is Coral Reef ?

Concentrated growth of a variety of corals in a localized habitat forms coral reef

A complex system which consist of many animals, including corals and plants

Why are they important ?

Protects coastline from erosion Employment to the Fisherman Tourism Contains most diverse ecosystem of

planet Provide habitats and shelter for many

marine organisms.

Coral Bleaching and causes

Cause of bleaching Major change in temperature (increase or

decrease) Oxygen starvation caused by an increase in

zooplankton due to overfishing Increased solar irradiance Increased sedimentation Bacterial infections

Coral Bleaching and causes

Change in salinity of water Elevated sea levels due to

global warming Low tide Exposed to sun Elevated thermal stress

resulting from increased sea surface temperatures (SST) leads to mass coral bleaching

Consequences of Coral Bleaching

Decrease in concentration of zooxanthellae causes paling

Increased concentration results in deepening of colour Coral provides protection to algae and algae provides

oxygen and gets rid of waste Without zooxanthallae corals are liable to starving Coral growth and reproduction are reduced Coral becomes increasingly susceptible to disease Prolonged bleaching causes death of the coral

Corals of Andaman Sea

Andaman Sea is a home to a total of 177 species of hard corals belonging to 57 genres

Area covered by reef is about 2000 sq. km, i.e. 6% of total island

Andaman harbors a rich population of corals, molluscus, fishes etc.

Most of reefs have luxuriant mangrove vegetation Pre-dominant species are Acropora formosa, Acropora

no-bilis, Acropora robusta, Acropora breuggemanni and Acropora grandis

Coral Bleaching in Andaman Sea Increased Sea Surface Temperature (SST) caused mass

bleaching effect in 1998, 2002, 2005 and 2010 Tsunami, 2004 exposed the reefs causing mass bleaching Most effected corals were maximum at Havelock Island (69.49%) South Button Island (67.28%) Nicolson Island (56.45%) Red Skin Island (43.39%) North Bay (41.65%) Chidiyatapu (36.54%)

Threats to Corals in Andaman

Natural Starfish feeds on Corals Use of Rotenone, a poison used for fishing Thermal Pollution Removal of mangrove forest Logging Excess use of coral reefs in medical purpose, i.e. for bone

transplant as reefs are rich in calcium Removal of reefs to be used in cement industries

Government Policies & Law of Action

“Coastal Regulation Zone Notification 1991” regulates onshore developmental activities for coastal environments

CRZN prohibits the collection and trade of corals “Wildlife Protection Act, 1972” provides protection for protected

areas and marine species Coral Reef Conservation is also included in “Environmental

Protection Act, 1972” and the National Conservation Strategy and Policy on “Environmental Development, 1992”

Action plan of “Ministry of Environment, Forest & Climate Change” plans on conservation and management of coral reef resources

“Indian Coral Reef Monitoring Network” has been framed.

THANK YOU Presented By : Abhinav Jha Akash Porte Amit Kumar Sahu Atul Sharma Dheeraj Neduthodi Sandeep Kumar Sinha Saurav kumar Jha Sumit Suman

Reference

https://scholar.google.co.in/scholar?hl=en&q=coral+bleaching+in+andaman+nicobar&btnG=

http://eprints.cmfri.org.in/9243/1/24.pdf

http://www.iisc.ernet.in/currsci/dec252000/1723.pdf

http://www.qm.qld.gov.au/microsites/biodiscovery/05human-impact/importance-of-coral-reefs.html