Coral reefs are typical type of marine landforms formed by the lime secreting polyps over a period of time. But, the shape and form of such reefs depend on the various factors including temperature, sunlight, oceanic topography, salinity, etc. So, let’s understand the process of growth and development of coral reefs.
Essential factors for the growth and development of coral reefs
As we know that the tiny polyps are too susceptible to adverse conditions. So, these fragile creatures can only thrive in certain locations in the oceanic atmosphere.
•Temperature of sea water-
Average water temperature is highly essential for the sustainable growth of coral polyps. It should neither be too low too high. For certainty, around twenty degree Celsius is ideal for better growth.
In case of higher or lower tempraure, the algae Zooxanthellae will abandon symbiotic relationship. And finally, polyps will die.
This is the reason why such marine organisms only survive in the tropical and sub-tropical regions of the world oceanic.
•Depth of the sea water
Though the polyps are benthos, they can’t thrive in the deep water. For the photosynthesis process, sunlight is prerequisite condition. Hence, beyond the 180 feet, the chances of survival are negligible.
Most importantly, these organisms cannot survive even in the absence of adequate water. That’s why these polyps are called too delicate to survive.
As I mentioned earlier that coral polyps are instrumental in absorbing calcium from sea water. So, calcium is necessary to make protective calcareous skeleton for themselves.
For this, certain degree of salinity is utmost important. Obviously, Coral polyps cannot thrive in fresh water nor in mere brackish.
You know that sea water salinity is 35 practical salinity units. And, for coral, it should be between 32 to 40 practical salinity units. Then, it is found in the areas of tropical and sub-tropical, away from riverine drainages.
•Sediment free water
Sediments can cause clogging effect on polyps. In the turbidity, Coral might not survive due to clogging. Hence, sediments free oxygenated clear water facilitates the ideal growth of colonies of tiny marine organisms.
Considering these conditions, the location may be somewhere in the tropical or sub-tropical regions, away from riverine drainages. Most strictly, the continental shelf and islands are generally preferred.
Different forms of coral reefs
On the basis of above discussed conditions, Coral reefs are classified in the following way:-
You might have heard about “The Great Barrier Reef of Australia.” It is the largest barrier reef of the world. It is formed in the proximity of coast. A comparatively deeper lagoon separates barrier reef from the coast.
Fringing reef is much closer to the coast compare to barrier. It is also gets separated by lagoon but less deeper.
•Unlike earlier two, it is found in the archipelago regions. These landforms are circular in shape but similar in structure. We know that continental shelf region is rich in marine ecology. And, these landforms are also part of this region.
So far, I have explained the pre-condition and the resultant types of coral reefs in the tropical and subtropical regions of the oceanic atmosphere. As per the data collected by the environmental global agencies, around 30 percent of marine species are being sheltered by this carbonated structure, constructed by the fragile tiny polyps. Therefore, the health of oceanic biodiversity largely depends on the growth and development of coral reefs.