GEOGRAPHY FORM SIX:CORAL COAST
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GEOGRAPHY FORM SIX:CORAL COAST
WATER MASSES CORAL COAST
-It is a coast which is made up of skeleton of the small marine organism is known as coral polyps consist of lime stone rocks resulting from skeleton of marine organism.
-Is a limestone rock which accumulates from the sea to the land.
Coral polyps
– Are living organism found on the marine and live in sheath like sacs composed of calcium carbonate (CaCo3) which they extract from ocean water.
Coral:
-Is the limestone rock made up of the skeleton of very small marine organism called coral polyps
Characteristics/coral polyps thrive under this condition.
i. Found in sea temperature around 21oc-30oc
ii. Sediment free salty water
iii. Found in lower tides. Sunlight which penetrate to a depth of at least 50m.
iv. Enough supply of oxygen and food (plankton ) v. Coral features normally develop at latitude of 30N and 30S because of warm ocean currents.
TYPES OF CORAL REEFS
Coral reefs are of various structure and in this basis broadly categorized into three types involving.
i. Fringing
ii. Barrier
iii. Atoll
i. FRINGING REEF: (Connected to coast)
-This consists of a plat form of a coral connected to and built out form a coast. The plate form surface is usually flat or concave and its outer edge sleepily to the sea floor.
-The lagoon is shallow separating the coast and edge of e.g. fringing reef along the coast of the reef Kenya and Tanzania.
GEOGRAPHY FORM SIX:CORAL COAST
ii. BARRIER REEF.
Similar to the fringing reef except that it is located several kilometers from the shore and is separate from it by a deep –water lagoon. The coral of a barrier reef is often joined to the shore, although the lagoon may be too deep for coral to grow on its bed.
iii. ATOLL:
A circular coral reef usually broken in several places, surrounding a shallow lagoon.e.g. Aldabra atoll that lies between Zanzibar and Malagasy
- It is concave shaped. (atoll formed in deep-sea )
Importance of coral Reefs (value)
i. Provide habitat for fish species and protection
ii. They are used as raw materials in manufacturing of cement in the cement industries (limestone)
iii. They attract tourist and lead to the earning of foreign currency.
iv. They are used as decorations in different building e.g. marble, some well shaped pieces of coral rock are usually stuck on the walls of the building with cement.
v. They also lead to the formation of island which can be used by man for different purpose like settlement or recreation.
vi. They also protect the coast against the strong waves, which can cause coastal land degradation and destruction of property.
vii. Source of income since some people collect coral stone and sell them.
Problem posed by coral reef in the world.
i. They are great barrier to navigation.
ii. Piece of coral rock that breaks during coral quarrying especially by using dynamite and the solution of coral rocks due to the presence of acidic material lead to water pollution.
iii. Coral reef can block the waves and lead to the failure in the formation of attractive beaches.
iv. Coral masses and discourage the growth of plants (sea weed) that tends to pollute, discourage, fishing, swimming and navigation.
CORAL REEFS FORMATION THEORIES
The classification of coral reef theories is divided into two major groups.
i. Those theories which require a change of sea level relative to reef foundation
ii. Those theories that hold that coral reef may develop without a change in sea level relative to the reef foundation.
Under the 1st group;
1.DARWIN`S THEORY
Of sinking land area and consequent rising sea level. Under those condition it is started the corals grown upward and outward converting fringing reef into barrier reef and final atolls.
These depend on the subsidence of land masses. As an island subsides, the coral reef grows upward and outward keeping pace with the subsidence.
2.DALY`S THEORY
The glacial control theory develops by Daly postulate a rising sea level due to the return of water to the sea following periods of glaciations.
This is based on the changing level of the searching and after the last ice age.
a.
Under the 2nd group;
GEOGRAPHY FORM SIX:CORAL COAST
MURRAY`S THEORY:
– The formation of the barrier reef doesn`t involve subsidence. He argues that coral reefs might have grown as a result of deposition of the coral debris on the seaward sides of the fringing reef. The deposited materials eventually form a base for further growth of polyps.
-The material deposited on the main hills or plateaus reduce the depth of the oceans thus making them sunlight and consequently the condition becomes conducive for polyps habitation. As these polyps die, they lead to the growth of coral reefs.
GLOBAL DISTRIBUTION OF CORAL REEFS
-As it has been already discussed coral reefs are in abundant supply on the esteem sides of the major land masses in the latitudes position in ten teen 30 North and South where sea temperatures reasonably high as warm ocean currents how nearly the coasts.
-The specific areas with coral reef include the following
-Along the edges of continents, E.g Along the edge of Australia where there is the greatest Barrier Reef of the world.
-Around island shores in the pacific ocean e.g. New Guinea and Caledonia
-Around the shores of volcanic peak especially in central and western pacific e.g. Fiji and Samoa islands.
-In the Atlantic Ocean in the west Indian Archipelago where there ia a group o f Island
-Around some islands in the Indian ocean e.g. Mauritius and Seychelles
Significance of coral reef to human being (constructive significance)
-They are used a raw materials to manufacture cement
-They are for building decorations
-They provide attractive sceneries and thus form the basis for tourism.
-Provide good breading stations for fish
-They have resulted into the formation of beautiful islands which used for recreational purposes
-They protect the coasts against erosion by marine waves
Destructive significance
-Coral plat forms encourage the growth of weeds which have a lot of setbacks
-Coral reefs impose barrier to navigation
-Contribute a lot to coast zone degradation because of being exploited
-They impose difficulties in fishing activities