Mentor’s Comment:

The question holds significance due to rising global warming and its effects on coral reefs as a result many marine flora and fauna are getting affected. Since this is the basic and straight question, not much needed to direct in this though few points should be kept in mind while framing structure.

Introduction should mention about the coral reefs and how they are formed in the subsequent para.

Further, talk about the significance like protecting cost lines from damaging, providing shelter to many marine species, source of nitrogen and other nutrients, carbon and nitrogen fixing, help in fishing to farmers, etc.

Next, mention how it gets affected due to global warming. Sensitive to temperature, leaching due to further warming etc.

Bring Conclusion based on the points of main body.

Model Answers:

Coral reefs are marine ridges or mounds, which have formed as a result of the deposition of calcium carbonate by living organisms, predominantly corals, but also a rich diversity of other organisms such as coralline algae and shellfish.

Formation of Coral Reefs:

 

 

• Coral reefs are reefs and the ecosystem attached to it.
• It is formed when a coral larvae come flowing from somewhere and attaches to some hard surface where it can attach itself against sea waves.
• This hard surface could be submerged rocks in the shorelines or the continental shelf seabed.
• Once the larvae attaches itself along the edges of island, continent of shoreline rocky system, lots of coral start growing in rocky surface forming colonies.
• As the corals die, their skeleton are deposited on the surface forming a rocky structure.It is a slow process.
• With time it develops into a complete ecosystem containing corals, exotic fishes, algae and other organism.
• There are certain special conditions which are necessary prerequisites for the growth and development of corals. That is why the reef building corals and their associates are not uniformly deposited throughout the tropical warm ocean waters.
• For the growth and development of corals the surface temperature of the ocean must be above 20°C. Corals cannot live if the temperature of the sea water falls below this.
• The water must be shallow, with a depth not exceeding 25-30 fathoms.
• With increasing depth, the amount of calcium as well as the temperature of water goes on decreasing, so that the coral polyps and other sea creatures which live on calcium carbonate do not thrive. That is why the reef building corals live in shallow waters and on the surface of the seas.
• The water must be normally saline, and, therefore, along the ocean margins where the water becomes fresh by the inflow of rivers, reef building corals do not grow and develop.
• The most essential prerequisite for the formation of coral reefs is the presence of submarine platforms which must lie near the sea shore, or should be attached to some islands.
• In India, corals are found in Lakshadweep Islands, Andaman & Nicobar Islands, Gulf of Mannar, Palk Bay etc.

Significance of Corals:

• Protect coastlines from the damaging effects of wave action and tropical storms
• Provide habitats and shelter for many marine organisms
• Are the source of nitrogen and other essential nutrients for marine food chains
• Assist in carbon and nitrogen fixing and help with nutrient recycling.
• The fishing industry depends on coral reefs because many fish spawn there and juvenile fish spend time there before making their way to the open sea
• The study of coral reefs is important for providing a clear, scientifically-testable record of climatic events over the past million years or so. This includes records of recent major storms and human impacts that are recorded by the changes in coral growth patterns.

Effects of Global Warming on Corals:

• Corals are very sensitive to temperature. Human activities of shipping, tourism, diesel boats led to rise in temperature on shoreline.
• Hence, there is decrease in around 40% coral reefs across world.
• Corals are sensitive toward salinity and acidity of water.
• With increased pollution, carbon dioxide is absorbed by ocean leading to rise in carbonic acid in water.
• As Coral has calcium carbonate as main component, it reacts with carbonic acid and slowly dissolves down.
• With rise in eco-tourism, snorkeling activities, cyanide fishing, oil spills and disposing of marine wastes in sea, the harmful effects are evident.
• Exploitation of coral reefs ecosystem for artificial aquarium, photography, deep water ports construction, pearl culturing, waste disposing to sea. All these leads to destruction of coral reefs.
• Global warming leads to glacial melt and hence more silt deposition in shoreline which causes coral destruction.

• Corals are important part of marine ecosystem as it provides habitat to many varieties of aquatic life. It also protects shoreline and hence it’s protection is sign of bio-diverse health.