prepared by t. madhavan, lecturer in zoology, directorate of school education., pondicherry. an...

Prepared by T. Madhavan, Lecturer in Zoology, Directorate of School Education., Pondicherry.

An Illustration for the students who aspire for medical studies.

CORALS – CORALS – reef buildersreef buildersto the session onwelcome



Beneficial animals provides

agronomic and Ornamentals

nutrition and medicines

luxurious materials

clothing materials

milk and meat



In India Coral reefs occur in

Gulf of Cutch on the west coast.

Andaman and Nicobar Islands,

Lakshadweep Islands,

and in south east coast,

CORALS – reef builders

Small plants like Zoanthella living in the coral tissues contribute to the yellow, green and brown colors of some reef forming corals



Coral rocks are actually the skeletal remains, primarily calcium carbonate secreted by living coral polyps.

Coral organisms belong to the phylum: Coelentrata.

All reef building corals living as large colonies.

- reef corals are typically shy, nocturnal feeders.

- they can grow only in shallow, tropical seas.

- they thrive only in crystal clear waters.

- they can’t survive below 20c.




During the day, the corals appear more or less lifeless by withdrawing their polyps.

At night time coral polyps stretch out their tentacles, probing the waters for food.

The reef looks like field of flowers.

Only in warm waters the coral polyps can extract calcium from the sea water and deposit as calcium carbonate in their skeletons.




CORALS - reef builders: Formation

Coral reefs are the result of the reproductive activities of millions of coral polyps over

several thousand years.

Corals spread by producing vast of minute ciliated Planulae larvae, through sexual

reproduction.

Planula larvae spend free swimming life, Later they settle on rocks and starts a new colony of

polyps by repeated fission or budding.



Corals - types



Categories and Structure of Coral Reefs

Coral reefs form in regions of the world where there are warm currents, mainly between the

Tropics of Cancer and Capricorn.

There are 4 main reef types: Fringing, Barrier, Atolls,

and

patch reefs.



Fringing reefs are coral reefs that grow in shallow waters and border the coast closely or are

separated from it by a narrow stretch of water.

Fringing (or apron) reefs directly border shorelines

This type is seen as a chain of well developed reefs starting from Rameswaram island and extending beyond Tuticorin. They are also present in

the Gulf of Cutch.

Coral Reefs: types



Barrier reefs are similar to fringing reefs except that they are separated from the shoreline

by lagoons that are often deep and wide:

{They are situated away from the coast and form the off-shore break waters parallel to the coasts or isolated

islands }The famous Great Barrier Reef of North Eastern Australia

which is 2012 KM. Long, is the largest of its kind.

Coral Reefs: types



Atolls are circular-shaped reefs that form on the rim of submerged volcanic islands.

Patch reefs are small, isolated formations that are not attached to a major reef structure.

Hawain and Carribian Islands are famous for

Atolls.

Coral Reefs: types



Corals are having

Decorative, Ornamental value [Ex.Corallium nobile used in Jewelllery]

Medicinal value [organ pipe coral (Tubipora) used in indigenous system]

Importance in the building habitat for Human and other animals.



Coral skeletons

1) are rich in calcium carbonate, magnesium contents,

2) used for building construction purposes and metalling the roads

3) serves as raw materials for the preparation of lime mortar & cement



Coral Reefs provide opportunities for the evolution of a number of fishes associated with coral reefs

Old coral reefs served as sea bird sanctuaries and have collected huge deposits of bird droppings (Guano)

Coral reefs act as natural barriers against sea erosion and cyclonic storms.

Provides unique habitat for large and diverse variety of organisms.

In several countries coral reefs helping in the tourism industry.



Encarta Encyclopedia standard international

Text book of Zoology (Biology) for XI standard.

Mann, K. H., Ecology of Coastal Waters - A Systems Approach, Chapter 6: Coral Reefs, 160-182, 1982

References:

prepared by t. madhavan, lecturer in zoology, directorate of school education., pondicherry. an...

Documents

reef corals

medical studies

corals reef builders

corals reef builders

corals types

meat slide

coral rocks

coral tissues