Coral reefs are known to be the largest living structures built by animals on Earth. They can even be seen on Earth from the space. They are basically the compilation of the skeletons of millions of corals over the period of thousands of years. The corals all pile up together in the reef to form the structure. Corals are biologically named as Anthozoa or flower-like animals.
Animals and plants come together in a unique bond and partnership in order to form the corals. Since they share the attributes of both- plants and animals- they can reproduce sexually or asexually. Asexually, they can break off from one point and reattach themselves to another point. Sexually, the young larvae float in the sea until it produces sexually and attaches itself to another larva. However, irrespective of whether they reproduce sexually or asexually, one thing is common- once they get attached, they cannot move around. It starts to grow in beautiful patterns by depositing limestone.
The corals which reproduce by branching tend to grow up at a faster rate of more than a foot per annum. While on the other hand, the corals which reproduce by mounding tend to grow up at a slower rate of less than one inch per annum. Coral reef supports more biodiversity in marine life than any other place in the ocean. Despite having hundreds of different species of animals and plants, each of the community lives in harmony and can recognise its species.
BIOLOGY AND ECOLOGY OF CORAL REEF
Coral reefs are wave resistant since they are made up of limestone and calcareous sediments of living organisms. However, the piles are extremely ecologically important owing to their rich biodiversity, production and tropic structure. In order for the coral reef to grow, there is a need of clear, shallow and warm water like in Indo-Western Pacific.
The main primary framework construction of the coral reefs is contributed by hydrocorals, scleractinian corals and coralline red algae. Coral reefs determine the physical structure of the coastline along with the ecosystems and environment adjacent to it. These act as a barrier against the sea in order to prevent themselves from getting drowned.
More than one-third of the marine life species reside on coral reefs or at least spend a part of their lives on coral reefs. They are related to anemones and jellyfish. A polyp is the singular name of a coral which has a tentacle-bearing mouth and a big stomach. These polyps use their tentacles to hunt for tiny organisms like plankton at night for food.
The coral colony is made up of thousands of similar polyps living together in harmony. Calcium carbonate exoskeleton is excreted by the polyps over time which forms up the skeletons. The skeletons then collectively form the coral reefs. Marine life species like fishes, microorganisms, invertebrates and even algae then establish their habitat around the reef.
Coral reefs are only found in the shallow regions with depth lesser than 150 feet in order for the sunlight to reach the organisms. But some of the coral reefs can go up to 450 feet deeper. They are mainly found in tropical and subtropical oceans all around the world.
IMPORTANCE OF CORAL REEFS
Even though coral reefs only occupy less than 0.2% of the seabed, they are extremely important in a biological sense. They help in absorption of elements derived from the ocean. They also help in preventing coastal erosion by absorbing waves energy. In case of storms and hurricanes, coral reefs help in reducing the damage by absorbing the energy of the danger.
They help in the protection of ecosystems by acting as a barrier. Their effect is so much so that humans build artificial concrete structures over some coasts. They act as a protective fringe, saving ecosystems. They act as a habitat for various species. Coral reefs also help in providing food to the residents of islands. They act as a resource for protein-rich fishes, molluscs, crustaceans etc. Owing to the fishing opportunities, they are of economic importance also- fetching billions of dollars every year.
Coral reef organisms also help in research and development. With the help of these, certain diseases can be treated like ulcers, leukaemia, cancers, cardiovascular diseases, HIV etc.
THE EMINENT DANGER TO CORAL REEFS
Owing to climatic change (due to carbon emission), the ocean has turned more acidic than ever which is causing a threat to the sediments on the reefs. The rising temperature of the ocean is already a cause of concern since it is causing the coral reefs to dissolve in water. For instance, reef sediments at Kaneohe Bay in Hawaii have already started to dissolve which can pose a danger to all the islands.
The coral reefs face imminent danger from human activities and damage. They might be massive, but sewage pollution, excessive fishing of marine species, soils from construction etc can cause major harm to them. A way of protecting coral reefs is through marine reserves and parks.