ppt on corals of andaman

7/31/2019 PPT on Corals of Andaman

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TOPICCORAL REEFS OF ANDAMAN ISLAND

CLASS F. Y. B.COM.

DIV C

ROLL NO. 359

ENVIRONMENTAL STUDIES 2011-12

CORAL REEFS OF ANDAMAN ISLAND


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CORAL REEFS OF

ANDAMAN


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TABLE OF CONTENTSR.

NO.

PARTICULAR SLIDE

NO.

1 INTRODUCTION TO ANDAMAN. 4

2 ANDAMAN & CORAL REEFS . 7

3 WHAT IS CORAL ? 9

4 (a) TYPES OF 3 MAIN CORAL REEFS . 10

4 (b) TYPES OF OTHER REEFS. 11

5 CORALS OF ANDAMAN. 13

6 IMPORTANCE OF CORALS. 14

7 THREATS TO CORALS. 18


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ANDAMAN ISLAND

INTRODUCTION

Located in Bay Of Bengal.

Geographical Area 8300 Sq Kms.

Emerged Part of a Mountain Chain lying on aridge.

Extend from Irrawaddy delta area of Burma ,continuing the trend of Arakan Yoma range.


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They consist of 350 islands, of which only 38 areinhabited along with a number of exposed islets androcks.

The principal of these are the North Andaman, Middle

Andaman with Ritchies archipelago to the east, SouthAndaman, little Andaman, Baratang and Rutlandisland.

Barren island lies to the east with Narcondum andother extinct volcanoes to the north (Reddiah, 1977).

The larger islands are mountainous and several arefully forested.


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Mangroves form extensive coverage along

the shores.

Annual rainfall is about 3000 mm and salinityof the waters is around 33 ppt.

The coral reefs are of fringing type andexcept for a few investigation reports thereefs of the area still largely remain unknown.

A deep oceanic ridge along 10N separates

the Andaman Group and the Nicobar group ofIslands. The general orientation is north-south


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Andaman & coral reefs

Coral reefs are underwater structures madefrom calcium carbonate secreted by corals.

Corals are colonies of tiny living animals found inmarine waters that contain few nutrients.

Most coral reefs are built from stony corals,which in turn consist of polyps that cluster in

groups. The polyps are like tiny sea anemones, to which

they are closely related.


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What is coral ?

Its a living organism!

It is an invertebrate

2 different types:1. Reef Building: Hermatypic

2. Solitary: Ahermatypic

Coral is cousins to jellyfish and anemones(Cnidarians)

Today we will talk mainly about reef buildingcoral


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Corals can build three main types ofreefs:

1. Fringing: grows close to shore

2. Barrier: also grows close to shore but has a

lagoon separating it from the shore

3. Atoll: a ring of coral that surrounds alagoon, often grows on a submergedmountain or volcano


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Types of other reefs Patch reef this type is an isolated, comparatively

small reef outcrop, usually within a lagoon orembayment, often circular and surrounded by sand orseagrass. Patch reefs are common.

Apron reef a short reef resembling a fringing reef,but more sloped; extending out and downward from apoint or peninsular shore

Bank reef a linear or semicircular shaped-outline,

larger than a patch reef

Ribbon reef a long, narrow, possibly winding reef,usually associated with an atoll lagoon


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Table reef an isolated reef, approaching an atoll type,but without a lagoon

Habili - this is a reef in the Red Sea that does not reachthe surface near enough to cause visible surf, although itmay be a hazard to ships (from the Arabic for "unborn").

Microatoll certain species of corals form communitiescalled microatolls. The vertical growth of microatolls is

limited by average tidal height. By analysing growthmorphologies, microatolls offer a low-resolution recordof patterns of sea level change. Fossilized microatolls canalso be dated using radioactive carbon dating. Suchmethods have been used to reconstruct Holocene sealevels.

Cays are small, low-elevation, sandy islands formed onthe surface of coral reefs. Material eroded from the reefpiles up on parts of the reef or lagoon, forming an areaabove sea level.


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Corals of andaman

Andaman has a fringing(grows close to shore) typeof coral reefs .


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Importance of coral reefs

Habitat for 1/3 of marine fishes

Habitat for tens of thousands of other

animals

The rainforests of the oceans


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Importanceof corals towards :

Protection of coastal line.

Economic resources

Biodiversity


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PROTECTION TO COASTLINES

absorb energy of ocean waves

reduce erosion of shoreline

storm damage

Flooding

ECONOMIC RESOURCES

Fisheries for foodFisheries for jobsTourismBuilding materialsAquarium trade


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Biodiversity The rainforest of the sea .

Genetic diversity .

Pharmaceutical.


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Threats to coral reefs

Natural disturbance: hurricanes , tsunamietc.

Predators like parrotfish ,butterfly fish , snailetc

Bleaching of corals due to loss ofzooxanthellae, high exposure to UV rays , etc.


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PHOTOS ON THREAT TO CORALS.

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Blast Fishing & Fishpoisoning

Coastal overdevelopmentMarine pollution

Global warming - bleaching

Overfishing Aquarium & Curio trade


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Thank You

ppt on corals of andaman

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