Table of Contents
What are Coral Reefs?
Oceanic coral reefs are made up of communities of tiny living things. They are the sub-aquatic coral polyp-based structures that calcium carbonate holds together. Just 0.1% of the ocean’s surface is occupied by coral reefs, which are also known as the tropical rainforest of the sea and constitute the habitat for 25% of marine species. They are typically located at depths of less than 150 feet in shallow locations. However, some coral reefs reach depths of as much as 450 feet.
The individual corals that are located on the calcium carbonate exoskeletons of their ancestors are known as coral polyps. Although there are corals in every ocean, the largest coral reefs are primarily found in the shallow, clear seas of the tropics and subtropics. The Great Barrier Reef in Australia is the longest coral reef system and stretches for more than 1,500 miles.
Types of Coral Reefs
Fringing coral reefs are coral reefs that are found extremely close to the surface and form the Boat Channel, a shallow lagoon. The islands and the borders of the continent are where the Fringing Reefs grow. Their seaward side slopes sharply into the deep sea when they emerge from the ocean’s deep bottom. The three coral reefs can all be found, but fringe reefs are the most frequent. Sakau Island in the New Hebrides, for instance, and South Florida Reef.
Among the three coral reefs, barrier reefs are regarded as the biggest, tallest, and broadest reefs. They form as a broken and uneven ring off the coast and parallel to the coastline. The longest and widest reef in the entire system, it extends over 100 km. The 1200-mile-long Great Barrier Reef in Australia is one example of a barrier reef.
A reef that encircles a sizable central lagoon and is generally circular in shape is known as an atoll. With a depth of 80 to 150 meters, this lagoon is primarily deep. The atolls are elliptical-shaped islands or platforms on submarines that are located apart from deep sea platforms. For instance, consider the atolls of Fiji, Suvadivo in the Maldives, and Funafoothis Atoll in Ellice.
In between fringing and barrier reefs, on the island platform or continental shelf, patch reefs generally form. The shallow lagoons of larger group reefs, or atolls, are where they are most frequently found. Patch reefs are typically located close to shore and can be found in waters that are between 10 and 20 feet deep. Examples include Bermuda, the Bahamas, the Caribbean, and the Pacific Islands.
How are Coral Reefs made?
Corals are super-organisms that include both plants and animals that are situated between populations and communities at the ecological level of organisation. The phylum Cnidaria’s class Anthozoa is responsible for the animal component, whereas zooxanthellae, an algae with chlorophyll pigment, makes up the plant component. Because of its capacity for photosynthesis, this alga can give coral polyps the carbon molecules they need to produce energy. The polyps defend the zooxanthellae in return.
Calcareous rocks called corals are formed from the polyps, or embryos, of microscopic sea organisms. Polyps draw calcium salts from seawater and use them to fortify their brittle bodies with sturdy skeletons. Coral reefs are created when freely roaming coral larvae adhere to hard sedimentary rocks or surfaces close to coastlines. New generations of polyps are produced from the skeletons of dead ones. Coral layers are created as a result of the cycle being repeated.
A reef, which eventually develops into islands, is the shallow rock that resulted from these depositions. Corals are tubular skeleton-shaped calcareous stone masses that are glued together and grow outward and upward. Coral reefs can take on a variety of shapes and hues based on the type of salts they are made of.
Coral Reefs in India
The length of India’s coastline is more than 7500 kilometres. There are hardly any Coral Reefs in India because of the subtropical climate. The Palk Bay, the Gulf of Mannar, the Gulf of Kutch, the Andaman and Nicobar Islands, and the Lakshadweep Islands are some of India’s most significant coral reef systems. The Lakshadweep reef is an example of an atoll among all of these coral reefs, while the others are all bordering reefs.
Palk Bay Coral Reefs
Palk Bay, which is located on India’s southeast coast and is centred at 9°17’N and 79°15′, is divided from the Gulf of Mannar by the Mandapam Peninsula and the Rameshwaram Island. The only fringing reef in Palk Bay is 25–30 km long and less than 200 m broad; it is located in the Pamban channel’s east–west direction. The highest depth of this reef is about 3 metres.
The Gulf of Mannar Coral Reefs
The 140 km-long Gulf of Mannar is located between Tuticorin and Rameswaram and is surrounded by a group of 21 islands. These 21 islands are a portion of the 140 km long and 25 km broad Mannar Barrier Reef, which is located between latitudes 8°47′ N and 9°15′ N and longitudes 78°12′ E and 79°14’E.
Andaman and Nicobar Islands Coral Reefs
The Andaman and Nicobar Islands are located between 91°-94° E longitude and 6°-14° N latitude. They are a group of 350 islands in the southern section of the Bay of Bengal, just 38 of which are inhabited. From the Burmese Irrawaddy Delta to the Arakan Yoma Range, these islands are located to the south. Nearly all of the Andaman and Nicobar group’s islands are bordering reefs.
The Gulf of Kutch Coral Reefs
The Gulf of Kutch occupies the northernmost portion of the Saurashtra Peninsula and spans an area of around 7350 square kilometres. It is situated between latitudes 22°15′ and 23°40′ north and 68°20′ and 70°40′ east. These bordering reefs are about 170 kilometres long and 75 kilometres wide at the mouth, where they narrow at a longitude of 72° 20′. Numerous coral reefs have mud deposits on them, which has severely deteriorated the state of such coral reefs.
Lakshadweep Islands Coral Reefs
The Lakshadweep Islands, which are dispersed throughout the Arabian Sea and lie between latitudes 8°N and 12°3’N and 71°E and 74°E, are around 225 km to 450 km away from the Kerala Coast. There are 36 little islands, 12 atolls, 3 reefs, and 5 submerged banks among the 32 km2 of islands, and lagoons encompass over 4200 km2. The water on these islands is warm and humid, ranging in temperature from 28 to 31 °C, and its salinity is between 34% and 37%.
India is said to have a coastline of about 7,517 kilometres, yet only 6,100 km of that coastline is on the continent. Fringing, barrier, and atoll coral reefs are the three main varieties found in India. There are many places in India where coral reefs can be found, such as the Gulf of Kutch, Gulf of Mannar, Palk Bay, Andaman & Nicobar, and Lakshadweep Islands. Some of the world’s most northerly reefs are in the northwest’s Gulf of Kutch. Coral reef swatches can also be found in Ratnagiri, Malvan, and Redi in south Bombay and at the Gaveshani Bank in Mangalore’s western region.
At Quilon, which is close to the coasts of Kerala and Tamil Nadu’s Enayem, corals may be seen running parallel to the shore. Corals are widely distributed along the east coast, between Parangipettai (south of Cuddalore) and Pondicherry. The Andaman and Nicobar Islands and the Lakshadweep Islands are abundant in healthy island corals.
Important Coral Reefs in the World
The majority of reefs may be found in the Pacific Ocean, Indian Ocean, Caribbean Sea, Red Sea, and Persian Gulf, all of which lie between the Tropics of Cancer and Capricorn. Corals can also be found farther from the equator in Florida and southern Japan, for example, where warm currents leave the tropics. Around the world, coral reefs are thought to encompass 110,000 square kilometres (284,300 square kilometres).
Coral Reefs Ecosystem
Coral reefs must develop in areas of shallow water. The distance between the reef’s surface and the water’s surface should not exceed 80 metres. The photosynthetic activities carried out by the Zooxanthellae require sufficient sunshine.
Hard or Semi-hard Surfaces
The coral polyp skeletons must be compacted, cemented, and solidified on a semi-hard or hard surface.
In locations with seas that are heavily contaminated with sediment, the lovely coral polyps die. Additionally, they vanish from seas that are murky. This is due to the fact that the presence of sediments and murky water restricts the amount of sunlight that can reach the algae that support their existence.
The warm ocean waters are intimately related to coral reefs. The water must be close to 20 degrees in temperature. So, coral reefs typically predominate on a continent’s eastern shore. This is not the situation with India, either, as the eastern seas are heavily contaminated with sediment.
Waters splashed with salt
The growth of coral polyps is greatly aided by the little saltiness of ocean waters. For the purpose of preserving their skeletons, the polyps draw calcium from the water. Therefore, for coral reefs to thrive, there must be a low salinity environment.
Rich nutritional supply
Because of the consistent flow of nutrient-rich water supported by ocean waves, coral reefs thrive in seawater. Coral polyps multiply more quickly when given nourishment.
Coral Reef Importance
Corals are essential to the marine ecosystem’s health. They are referred to as the ocean’s rainforests since they are home to a variety of habitats. Many different kinds of fish can dwell in corals. The marine ecosystem’s main source of food is corals.
The coastal regions are shielded by coral reefs from powerful ocean currents and waves. They offer defence against cyclones and ocean storms. These natural barriers have gained extra importance as storms in India are becoming more frequent as a result of climate change.
Fish that are found in and around coral reefs provide millions of people, mostly those who live along coastlines, with a wholesome supply of protein. Some fishing companies rely only on coral reefs and the fauna they draw.
As the sea’s pharmacy, coral reefs are believed to be. The corals draw certain fish, and some of those fish leave behind chemical residues that resemble those seen in hospitals.
According to a recent study by the Indian Institute of Meteorology, corals along the northwestern coast provide information on the patterns of the arrival and departure of the Indian monsoon.
Due to these stunning corals, the tourism industry accounts for the majority of the gross domestic product (GNP) of nations with coral reef industries. According to research, coral reefs are worth $10 billion, and they provide about $360 million in direct economic benefits annually.
Coral Reef Bleaching
90% of the nutrients produced by the algae are delivered to the coral hosts through a symbiotic interaction between the coral and zooxanthellae. However, this association is negatively impacted by extreme environmental stress, which results in the disappearance of symbiotic algae (zooxanthellae). As a result, coral bleaching occurs when the coral’s translucent tissue allows visibility of the white calcium-carbonate exoskeleton. In the absence of algae, corals become fragile and start to deteriorate after a few weeks of high sea temperatures.
Threats to Coral Reefs
The coral ecosystem is in danger because of the increasing acidity of the oceans brought on by global warming. Additionally, as glaciers throughout the planet melt, sea levels are rising. Because of inadequate sunshine and drowning caused by rising sea levels, coral reefs grow slowly.
When the waters get warmer, coral bleaching occurs. Due to their limited temperature tolerance, corals experience stress and emit symbiotic algae as a result. They lose their source of life when the algae is gone, which results in their extinction.
Corals are dying because of marine pollution brought on by plastic waste and other activities. To breathe, coral reefs require both air and space. We might lose them sooner than we anticipated due to the increasing levels of sea pollution.
Stronger Storms and Acidification of the Ocean
Increased storm intensity has resulted in ocean waves that break and harm coral reefs. They may even destroy colonies and make them dangerous places to live. The pH levels rise as more and more CO2 is absorbed by the water. Coral skeletons weakened by high pH levels are more susceptible to disease and storm damage.
Coral polyps have in-built UV rays protection. However, now that the radiation is increasing, the corals in shallow waters can get damaged and destroyed.
Largest Coral Reef in the World
The Great Barrier Reef, which consists of approximately 2,900 distinct reefs and 900 islands, is the biggest coral reef system in the world. Over an area of around 344,400 square kilometres, it extends for more than 2,300 kilometres. The reef is in the Coral Sea, off the Queensland coast of Australia.
Great Barrier Coral Reef
With over 2,900 distinct reefs and 900 islands, it is the largest and most magnificent coral reef environment on earth. The coral reef is situated in Australia’s Coral Sea (North-East Coast), off the coast of Queensland. It is the largest single structure built by living things that can be viewed from space. Billion microscopic organisms are known as coral polyps formed and constructed this reef structure.
Coral Reef Animals
The multitudes of organisms that depend on reefs for survival include fish, corals, lobsters, clams, seahorses, sponges, and sea turtles. In addition, to being living museums, coral reefs also preserve thousands of years of history.
Coral Reefs FAQs
Q What is coral reef explain?
Ans. Coral polyp colonies, often known as coral reefs, number in the hundreds to thousands. These marine invertebrates are sessile, or fixed in place permanently, and have strong calcium carbonate exoskeletons.
Q Is coral reef plant or animal?
Ans. Corals do not produce their own food, in contrast to plants. In reality, corals are creatures. The branch or mound we commonly refer to as “a coral” is really composed of thousands of microscopic creatures called polyps.
Q Why coral reef is important?
Ans. Coral reefs offer chances for recreation, serve as a barrier against erosion and storm damage, and support local economies. They are also a source of fresh medications and food. More than 500 million people rely on reefs for safety, income, and food.
Q What is coral reef made of?
Ans. Massive limestone formations known as coral reefs are created by coral polyps. Coral reefs, sometimes referred to as the “rainforests of the sea,” are home to about 25% of all known marine species.
Q Is coral harmful to humans?
Ans. Zoanthid coral species like Palythoa and Zoanthus can harbour palytoxin, a very poisonous and potentially fatal chemical compound. Therefore, palytoxin toxicity is the same as coral toxicity. Hobbyists who keep aquariums in their homes and aquarium shop employees may be more exposed.