Coral reefs are incredibly diverse ecosystems that are built primarily by coral polyps. These polyps come in various forms, including large reef-building colonies, flowing fans, and small, solitary organisms. Scientists have identified thousands of different coral species, some of which live in shallow, warm, tropical seas, while others thrive in the cold, dark depths of the ocean.

Each coral polyp contributes to the growth of the reef by adding its own exoskeleton to the existing structure. Over time, these tiny contributions add up, resulting in the formation of massive coral reefs that serve as important features of the marine environment.

Coral reefs are found in oceans all over the world, from the Aleutian Islands to the Caribbean Sea. The largest coral reef systems are typically found in clear, shallow waters in the tropics and subtropics, with the Great Barrier Reef in Australia being the largest of them all at over 1,500 miles long.

Conditions for Coral:

Shallow water coral reefs have a mutualistic relationship with photosynthetic algae called zooxanthellae that provide them with food and oxygen. Deep-sea corals don’t have this relationship and rely on plankton and organic matter for energy. Corals require stable climatic conditions, warm and clear saltwater with abundant phytoplankton. They are highly sensitive to pollution and climate change.

• Stable climatic conditions
• Perpetually warm waters with narrow temperature ranges (around 20°C between 30°N and 30°S latitudes)
• Clear saltwater
• Abundant supply of phytoplankton
• Minimal pollution

Corals thrive in areas with little variation in temperature, and phytoplankton supply essential oxygen and food for coral growth. Clear salt water is ideal for coral development, while fresh and highly saline water can be harmful. Corals are also highly vulnerable to even small increases in marine pollution or climate change due to their fragile nature.

There are three main types of coral reefs:

1. Fringing reefs: These are the most common type of coral reef, found close to the shore and surrounding islands or continents. They grow in shallow waters and are separated from the shore by a lagoon.
2. Barrier reefs: These reefs are found further from the shore, separated by a wider and deeper lagoon. They grow parallel to the shoreline and can be found along the edges of continental shelves.
3. Atolls: Atolls are circular or horseshoe-shaped reefs that encircle a lagoon. They are usually found in the middle of the ocean and are formed from the tops of submerged volcanoes.

Coral reefs play a vital role in protecting coastlines from storms and erosion, and also offer recreational opportunities and employment to local communities. They provide a source of food and new medicines, and are essential to the livelihoods of over half a billion people who depend on them for income and protection. In addition, fishing, diving, and snorkeling activities around coral reefs contribute significantly to the local economy, adding hundreds of millions of dollars to local businesses. The net economic value of the world’s coral reefs is estimated to be nearly tens of billions of U.S. dollars annually. Furthermore, these ecosystems hold cultural significance to indigenous communities worldwide.

Coral reefs face several threats, including:

1. Climate change: Rising temperatures and ocean acidification caused by climate change can harm corals and their symbiotic algae, leading to coral bleaching and death.
2. Overfishing and destructive fishing practices: Overfishing can damage coral reefs by removing key species that help maintain the balance of the ecosystem. Destructive fishing practices, such as the use of dynamite or cyanide, can also destroy coral reefs.
3. Pollution: Marine pollution, including runoff from land-based sources, can harm coral reefs by introducing nutrients that promote the growth of harmful algae and pathogens.
4. Coastal development: Construction and development near coastal areas can lead to habitat destruction and sedimentation, which can suffocate corals and reduce water quality.
5. Invasive species: Invasive species, such as the crown-of-thorns starfish, can overpopulate and consume large amounts of coral, causing significant damage to the reef ecosystem.

Coral bleaching is a phenomenon that occurs when corals expel the microscopic algae living in their tissues, called zooxanthellae. These algae provide corals with essential nutrients and energy through photosynthesis. However, when corals experience stress from factors such as increased water temperature, pollution, or other environmental disturbances, they may expel their zooxanthellae, leaving their tissues transparent and their white skeletons visible, hence the term “bleaching.”

Without the energy and nutrients provided by zooxanthellae, corals are more vulnerable to disease and may eventually die. Coral bleaching is a global problem, affecting coral reefs worldwide and is exacerbated by climate change, as increasing water temperatures and ocean acidification cause widespread coral stress.

In recent years, coral bleaching has become more frequent and severe, with some coral reefs experiencing multiple bleaching events within a few years. Scientists and conservationists are working to address the causes of coral bleaching, including reducing carbon emissions to mitigate climate change, reducing pollution, and improving coral reef management and conservation efforts.

Protection of Coral reef in India:

To promote the growth and protection of coral reefs in India, the government has implemented both regulatory and promotional measures. The Coastal Regulation Zone notification and Island Protection Zone notification are among the regulatory measures taken to protect corals by controlling development activities along the coast. Several laws, including the Indian Forest Act of 1927, the Forest Conservation Act of 1980, and the Indian Fisheries Act, are also applicable to coral reef areas. Additionally, the Integrated Coastal and Marine Area Management program, initiated in 1998, aims to manage the coastal and marine areas through the development of model plans for areas such as the Gulf of Kutch.

The protection of coastal and marine areas in India is facilitated by the National Coastal Zone Management Authority (NCZMA) and State Coastal Zone Management Authority. The Ministry of Environment and Forests (MoEF) has incorporated studies on coral reefs within the Coastal Zone Studies (CZS). However, despite these efforts, a specific program aimed at the protection of coral reefs in India is yet to be established. This gap is impacting the effectiveness of coral protection initiatives undertaken by state governments.