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Coral reefs are large underwater structures composed of coral skeletons, which are marine invertebrates. Corals that build coral reefs are called hermatypic or "hard corals" because they extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their soft, bag-like bodies. The largest coral reefs are found in the limpid, shallow, turbulent waters of the tropics and subtropics where they grow rapidly.
Corals can be identified by their vibrant color, their shapes and can be called brain corals, whips, elkhorn corals, gorgonians or colorful trees or plants. Some species of corals, such as coral coral, are hermaphrodites, producing both eggs and sperm, while elkhorn corals are gonochoric, creating colonies of all males or females. Among these colonies of corals, all the polyps of the same colony will produce only spermatozoa; for breeding, they rely on a nearby colony that produces only eggs.
Coral reefs occupy less than 1% of the sea floor – all combined would represent an area of approximately 285,000 square kilometers, roughly the size of the state of Nevada in the United States.
About 25% of all known marine species depend on coral reefs for food, shelter and reproduction. Sometimes called "tropical forests of the sea" for their biodiversity, coral reefs are the main habitat of over 4,000 species of fish, 700 species of corals and thousands of other plants and animals.
Economic importance of coral reefs:
The value of coral reefs has been estimated at $ 30 billion and perhaps up to $ 172 billion a year, providing food, protecting shorelines, tourism-based jobs and even drugs. About 5 to 15 tonnes of fish and seafood can be produced per km2 of reef on a healthy reef system. On average, fish catches associated with reefs can also account for 25% of the total catch of fish in developing countries.
Healthy reefs act as natural barriers, protecting coastal cities, communities and beaches from breaking waves. The fishing industry depends on coral reefs because many fish spawn and juveniles spend their time in the corals before going offshore.
The Great Barrier Reef, which is more than 2,400 kilometers long, generates over $ 1.5 billion annually for the Australian economy through fishing and tourism.
Other high economic values of corals include: Decorative value in jewelery and ornaments – Construction of buildings and roads (coral skeletons, especially species like porites, are used as building materials) In the cement industry, corals contain a large amount of calcium carbonate.
Coral aquaculture, agriculture and gardening:
Increasing demand for corals for human needs has also allowed coral aquaculture to be developed for commercial cultivation. Agriculture and gardening through aquaculture have also shown a positive hope for the restoration of lost reefs through their replanting and reef conservation.
It also decreased the chances of early death of juvenile corals. Coral aquaculture is mainly practiced by researchers, scientists and by ornamental traders and businessmen for the trade in ornamental corals and by many private organizations for their passion for aquariums.
An underwater pharmacy:
Scientists have already developed many medical treatments from resources found in the world's oceans. For example: Secosteroids, an enzyme used by corals to protect themselves from diseases, are used to treat asthma, arthritis and other inflammatory disorders.
Bryozoan Bugula neritina, a widespread fouling organism in temperate and tropical climates, is a source of bryostatin, an anticancer compound. The National Cancer Institute of the United States recently collected more than 26,000 books on the population.
Blue-green algae, commonly found in Caribbean mangroves, are used to treat small cell lung cancer. The National Cancer Institute has also approved blue-green algae for the treatment of melanoma and certain tumors. Twenty-five other marine-derived drugs are being evaluated in human trials.
A series of organic chemicals isolated in a soft coral called the Caribbean Whip seem to have an impressive anti-inflammatory effect on human skin.
Bioactive molecules produced by marine invertebrates such as sea sponges, tunicates and sea hares showed potent antiviral, antitumor and antibacterial activity.
Researchers are studying bivalves, a class of molluscs, to learn about aging processes, including metabolic activity and environmental stressors.
Threats on coral reefs:
But coral reefs are threatened by human activities. The increasing acidification of the ocean – caused by the absorption by the oceans of huge amounts of carbon dioxide (CO2) emitted by the burning of fossil fuels, inhibits the ability of coral to produce the exoskeletons of calcium carbonate which they need to shelter.
Water pollution also wreaks havoc on coral reefs. Pesticides and agricultural fertilizers, oil and gasoline, wastewater discharges and sediments from eroded landscapes hinder the complex relationships between plants, corals and other animals that are part of reef ecosystem.
As ocean temperatures increase as a result of global warming, coral polyps expel the zooxanthellae they depend on for food. Once they are gone, the coral also loses its brilliant color, and all we can see is the white exoskeleton; this is what is called coral bleaching. Coral colonies prone to bleach usually die.
And fishing practices such as cyanide fishing, explosive fishing with explosives and overfishing with trawlers can destroy a millennial coral reef in minutes. Each of these forces alone is capable of causing the global collapse of coral reefs; together, they ensure it.
Ahamad
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