If you frequently watch nature shows, you must have seen the mystic world of the oceans and seas. The underwater world is beautiful and mesmerizing. It's a totally different world, containing innumerable habitats and sustaining countless aquatic animals and plants. Marine life contributes significantly in maintaining the Earth's ecological balance. Some of the most important habitats of aquatic life are coral reefs. What are Coral Reefs? Coral reefs are often hailed as the rainforests of the sea. Coral reefs are colonies of marine organisms which secrete calcium carbonate over a long period of time, to form a hard outer skeletal covering. These creatures are called polyps. Corals can reproduce either sexually or asexually. Fringing reefs, barrier reefs, and coral atolls are the three main types of coral reefs. Why are Coral Reefs Important? Not only do coral reefs make their own ecosystem, many other aquatic organisms also depend on coral reefs for life and shelter. Sustaining Tropical Marine Ecosystems Coral reefs form an important part of the tropical marine biology. Many marine creatures spend their lives in moving from mangrove ecosystems to sea grass beds and then coral reefs, thereby transferring nutrients and connecting life. Mangrove trees are known to grow to a height of 15 meters and their roots are always in proximity to the shores. The root systems serve as a source of underground water ecosystem for marine animals. Sea grass beds are found in totally shallow bays. The coral reefs lying at the bottom, protect the mangrove trees and sea grass beds from erosion by the waves. Primary Producers In the 'circle of life', humans along with every other organism plays a significant role, coral reefs aren't an exception. According to biologists, primary productivity is described as the storing of organic and inorganic compounds by the process of photosynthesis. Like trees and plants are known to reduce our carbon levels, corals also help in reducing the effects of CO₂. Coral reefs support the food chain by being a food for tropical fish and other marine animals that serve as food for animals, higher in the food chain. This maintains the balance of the ecosystem. Coral reefs are among the most populous ecosystems in the world, and their elimination would be a threat to countless other species of fish and aquatic creatures. Tourism Coral reef destinations are recognized as the biggest tourist attractions all over the world. It's no surprise that the Great Barrier Reef in Australia, the world's largest coral reef ecosystem garners a USD 1 billion from the tourism industry built around it. Thanks to the UN, it has been declared a World's Heritage Site, and is meticulously taken care of. Though coral reef tourism is believed to be an alternative source of income for the poor coastal communities, none can guarantee how long will the poor countries be able to preserve these beautiful sites. Coastal Protection Coral reefs are known to break the power of waves and reduce their intensity, thereby protecting coastal areas from destruction. They can be called nature's defense mechanism to prevent coastal soil erosion and flooding. Medicinal Research A major breakthrough in the treatment of HIV infections is the medicine AZT, which is based on chemicals found in sponge reefs in the Caribbean. Pharmaceutical companies have now targeted coral reefs for medicines on cancer and other terminal diseases as well. Cultural Significance Coral reefs are worshiped as life-sustaining forces in numerous cultures around the world. The most significant among these are the islands of Fiji, where coral reefs and their waters are thanked and revered through ceremonies and prayers. In Fiji, the traditional reef management system has worked wonders. For Fiji, coral reefs are a symbol of life and reverence, and the same is true for many other cultures around the world!! Threats While efforts to develop artificial reefs are ongoing and promoted in many parts of the world, the problems faced by coral reefs need a timely response from the human fraternity.

• Rising sea water temperature owing to global warming causes "bleaching" of the coral reefs and ultimately their death.
• Pollution of the oceans affects the delicate ecosystems in reefs massively.
• Overfishing and poor fishing practices damage the balance of underwater ecosystems.
• Natural events in the forms of hurricanes, cyclones, and tsunamis have the potential to disrupt these systems.

The importance of reefs is being increasingly highlighted in newspapers and science journals nowadays, and people are becoming aware of the crucial role they play in our lives. At an individual level, we should at least try to make people aware of their importance and must make changes in our lifestyle that help in significantly reducing the effects of global warming.