Coral Reefs Biodiversity key for Climate Change Adaptation

An underwater habitat that is distinguished by the presence of reef-building corals is known as a coral reef. Colonies of coral polyps are what give rise to reefs, which are then kept together by calcium carbonate.  The vast majority of coral reefs are constructed from stony corals, which have polyps that cluster together in groups.

The animal phylum Cnidaria is home to a class called Anthozoa, which also houses sea anemones and jellyfish. Coral is a member of this class. Corals, in contrast to sea anemones, produce a rigid exoskeleton made of carbonate that both supports and protects the coral. The majority of reefs flourish in water that is warm, shallow, transparent, bright, and agitated. The first coral reefs emerged 485 million years ago, at the beginning of the Early Ordovician period. They succeeded the microbial and sponge reefs that had existed during the Cambrian period.

Shallow coral reefs, which are sometimes referred to as the rainforests of the sea, contain some of the most diverse ecosystems on Earth. However, they are home to at least 25 percent of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, sponges, tunicates, and other cnidarians, although taking up less than 0.1 percent of the total surface of the world’s oceans (or roughly half the area of France). Coral reefs are most successful in areas of the ocean that contain relatively little nutrients. They are most frequently discovered at shallow depths in tropical waters, however there are examples of coral reefs in deep water and cold water on a smaller scale in other regions of the world.

Biodiversity

Coral reefs are responsible for the formation of some of the most productive ecosystems on Earth. They do this by creating intricate and diverse marine habitats that are home to a wide variety of other organisms. Mangrove forests at high tide level and seagrass meadows in between have a mutually beneficial relationship with fringing reefs just below low tide level. The reefs protect the mangrove forests and seagrass meadows from strong currents and waves that would damage them or erode the sediments in which they are rooted, and the mangrove forests and seagrass meadows protect the coral from large influxes of silt, fresh water, and pollutants. Numerous animals that live in coral reefs derive benefits from the high level of environmental diversity that exists there. These animals, for instance, may find food in the sea grass and use the reefs for protection or breeding.

Reefs are home to a wide variety of animals, including fish, seabirds, sponges, cnidarians (which includes some types of corals and jellyfish), worms, crustaceans (including shrimp, cleaner shrimp, spiny lobsters and crabs), mollusks (including cephalopods), echinoderms (including starfish, sea urchins, and sea cucumbers), sea squirts, sea turtles, and sea snake With the exception of humans, animals are extremely uncommon on coral reefs; the primary exception to this rule is made up of visiting cetaceans like dolphins. Some species consume the corals themselves, while others graze on the algae that grows on the reef. There is a positive correlation between reef biomass and the number of species.

The large number and variety of hiding spots, also known as refuges, within coral reefs are the single most important element that contributes to the high biomass and diverse population of species that are found within coral reefs.

Algae

Reefs are in constant danger of being overrun by algae because of the presence of these organisms. It is possible for algae to eradicate coral reefs by outcompeting them through overfishing and the introduction of an excessive amount of nutrients from land. An increase in nutrient levels may occur as a consequence of the runoff of sewage or chemical fertilizer. The presence of nitrogen and phosphorus in runoff waters might lead to an excessive growth of algae. There are times when algae are able to outcompete coral for space. After that, the algae will reduce the oxygen supply that is available to the reef, which will cause the coral to suffocate. Reduced oxygen levels can cause calcification rates to drop, which in turn weakens the coral and makes it more susceptible to disease and other forms of environmental damage. A significant proportion of the coral reefs that were investigated were home to algae.Turf algae, coralline algae, and macroalgae are the three types of algae that make up the algal population. Because some sea urchins, including Diadema antillarum, consume these algae, there is a possibility that the risk of algal encroachment will be reduced.

Sponges

Sponges are absolutely necessary for the proper operation of the system that makes up the coral reef. Corals and algae in coral reefs both contribute to the production of organic material. This is accomplished by passing the material through sponges, which break down the organic matter into smaller particles that are then taken up by algae and corals.

Fish

Coral reefs are home to more than 4,000 different types of fish. It is not yet known what the causes of this variety are. Hypotheses include the “lottery,” in which the first (lucky winner) recruit to a territory is typically able to defend it against latecomers; the “competition” hypothesis, in which adults compete for territory, and less-competitive species must be able to survive in poorer habitat; and the “predation” hypothesis, in which population size is a function of post settlement piscivore mortality. Reefs that have been destroyed provide a far lower yield of fish than healthy reefs, which can produce up to 35 tonnes of fish per square kilometre annually.

Invertebrates

Seaweed is the primary food source for sea urchins, dotidae, and sea slugs. It is possible for certain species of sea urchins, such as the Diadema antillarum, to play a significant role in preventing algae from taking over coral reefs. Researchers are researching the use of native collecting urchins, known scientifically as Tripneustes gratilla, to see whether or not they have the ability to act as biocontrol agents to reduce the impact of invading algae species on coral reefs. Sponges are the food of choice for nudibranchia and sea anemones.

Numerous invertebrates, which are collectively referred to as “cryptofauna,” make their home within the coral skeletal substrate itself. These invertebrates either burrow into the skeletons (via the process of bioerosion) or make their home within pre-existing voids and crevices. Sponges, bivalve mollusks, and sipunculans are all examples of animals that can be found burrowing into rocks. The reef is home to a wide variety of different species, the most common of which are crabs and polychaete worms.

Seabirds

Coral reef ecosystems are essential for the survival of many species of seabirds, including several that are threatened with extinction. For instance, the Midway Atoll in Hawaii is home to approximately three million seabirds, including two-thirds (1.5 million) of the world’s Laysan albatross population and one-third of the world’s black-footed albatross population. There are particular areas on the atoll that are suitable for the nesting of each species of seabird. There are 17 different types of seabirds that can be found on Midway. After widespread feather collection in the late 19th century, the short-tailed albatross is the most endangered species, with less than 2,200 living today as a result.

Conclusion 

Coral reefs form some of Earth’s most productive ecosystems. They do this by building complex and diverse marine environments. High tide mangrove forests and seagrass meadows benefit bordering reefs during low tide. The reefs protect mangrove forests and seagrass meadows from powerful currents and waves that might damage them or erode their sediments, and the forests and meadows protect coral from silt, fresh water, and pollutants. Coral reefs’ enormous environmental diversity supports many creatures. These species eat sea grass and use reefs for protection and reproduction