About coral reefs
Coral reefs are created by millions of tiny polyps forming large carbonate structures. Coral reefs are the largest living structure on the planet, and the only living structure to be visible from space.
Corals are found across the world’s oceans, in both shallow and deep water, but reef-building corals are only found in shallow tropical and subtropical waters. This is because the algae found in their tissues need light for photosynthesis and they prefer water temperatures between 22-29°C.
There are also deep-sea corals that thrive in cold, dark water at depths of up to 20,000 feet (6,000 m). Both stony corals and soft corals can be found in the deep sea. Deep-sea corals do not have the same algae and do not need sunlight or warm water to survive, but they also grow very slowly. One place to find them is on underwater peaks called seamounts.
Types of coral reefs in India
India has three major prevailing types of coral reefs:
1. Fringing reefs
Fringing reefs evolve and develop near the continent and remain close to the coastline. These reefs are separated from the coastline by small, shallow lagoons. They are the most commonly found reefs in the world.
2. Barrier reefs
Barrier reefs are found offshore on the continental shelf. They usually run parallel to the coastline at some distance. A deep and wide lagoon is located between the coastline and the barrier reef.
Atolls are formed on mid-oceanic ridges. They are shaped circularly or elliptically and are surrounded by seas on all four sides and have shallow waters in the center called a lagoon.
Coral reefs in India:
India has four coral reef areas:
- Gulf of Mannar
- Andaman and Nicobar Islands
- Lakshadweep islands
- The Gulf of Kutch
Ideal environmental conditions for corals to grow
Coral reefs have certain conditions that must be met for them to grow in full bloom.
1. Shallow water
Coral reefs need to grow in shallow parts of the water. The surface of the reef shouldn’t be more than 80m from the water surface. The Zooxanthellae need adequate sunlight for their photosynthesis processes.
2. Semi-hard or hard surface
The semi-hard or hard surface is a precondition for compaction, cementation and solidification of the coral polyps skeletons.
The beautiful coral polyps perish in areas filled with sediment-filled waters. Moreover, they cease to exist in opaque waters. This is because the presence of sediments and opaque water limits the passage of sunlight to the algae that sustains their life.
4. Warm water
Coral reefs are directly connected with warm oceanic waters. The temperature of the water must be around 20 degrees. Hence, coral reefs generally prevail on the eastern coasts of continents. However, this is not true in the case of India as the eastern waters are filled with high amounts of sediment matter.
5. Saline-filled waters
The slight salt in ocean waters is extremely important for the development of coral polyps. The polyps extract calcium from the water to protect their skeletons. Hence, mild salinity is a necessity for coral reefs to flourish.
6. Rich supply of nutrients
Coral reefs flourish in sea waters because ocean waves support the constant supply of rich nutrients. Coral polyps multiply faster when supplied with nutrients.
Coral Reefs are important to Marine life
- The health of the marine ecosystem is dependent on corals.
- They support a wide range of ecosystems and hence, are called the rainforests of the ocean.
- Corals provide a place to live for a huge variety of fish.
- Corals are a primary source of food in the marine ecosystem.
Coral reefs have a somewhat similar significance
1. Coastal protection
Coral reefs act as a barrier and protect coastal areas from strong ocean currents and waves. They provide protection from ocean storms and cyclones. With the increasing amount of cyclones in India due to climate change, these natural barriers have become excessively important.
2. Food source
Fish that live in and around coral reefs are a healthy source of protein for billions of people, mainly living on coastlines. Some fishing industries are entirely dependent on the coral reefs and the wildlife that it attracts.
3. Medicinal properties
Coral reefs are said to be the medicine chests of the sea. Some fish that the corals attract, leave behind some chemical compounds that are similar to the ones used in human hospitals.
A new study by the Indian Institute of Meteorology has stated that corals along the north-western coast provided insights on the patterns of the onset and withdrawal of Indian monsoons.
Most of the gross national product of countries with coral reef industries comes from the tourism sector due to these beautiful corals. A study had estimated that the value of coral reefs was $10 billion and the direct economic benefits were approximately $360 million per year.