Coral reefs: where are they found, how are they formed and which are the most beautiful

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Martí Micolau

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Coral reefs are underwater forests rich in living species. Consider that at least 25% of all marine species in the world live in the waters of coral reefs. Also known by the English name Reef, the majority of coral reefs in the world are actually made up of many smaller fractions, connected in a single ecosystem.

Here's everything you need to know about barrier Reef: how it is formed, where it is in the world, and which are the biggest and most beautiful!


  1. How the coral reef is formed
  2. The most beautiful coral reefs in the world
  3. Coral bleaching and death
  4. Curiosities about the coral reef
  5. User questions and comments

How the coral reef is formed

The spectacular coral reefs they are "built" by the Antozoi, small octopus-shaped organisms that need clear, illuminated and oxygenated waters in order to live. These tiny polyps they gather in colonies called Coralli, and live in symbiosis with unicellular algae called zooxanthellae.

Through the photosynthesis process of these algae, the small organisms constitute a sort of skeleton of calcium carbonate which assumes a protective and support function. Over time, these skeletons merge with each other creating coral structures hard as rock. The structures are called "barriers" when they are separated from the coast by a shallow lagoon. When they are found near the coast, they are called "coral reefs".

The most beautiful coral reefs in the world

As already specified, corals need certain conditions to live, including good lighting, sea temperatures between 20 ° and 30 ° C and high salinity. These conditions unite the areas of the central Pacific and the Australian east coast, not surprisingly, almost all of the existing reefs are concentrated in these areas. On the contrary, the western coasts of the continents are not suitable for developing barriers due to cold currents.

But where are the most beautiful and largest barriers in the world located? Let's find out in the following ranking.

1 - Great Barrier Reef, Australia

La Great Barrier Reef of Australia it is located off the coast of Queensland and is known to be the largest coral reef in the world. It is made up of some 3.000 barrier systems. Just think that it is so big that it is visible from space.
Since 1981 it has been part of the UNESCO World Heritage Site.

2 - Coral reef in the Red Sea, Egypt

The Red Sea coral reef is found off the coasts of Egypt, Israel and Saudi Arabia. Ten percent of the 1.200 species found in this coral reef are unique to this area. This place includes the Blue Hole of Dahab, one of the most popular and dangerous dive sites in the world.

3 - Reef of New Caledonia, New Caledonia

The New Caledonian Barrier Reef, in the South Pacific, is the third longest barrier in the world. More than 1.000 different species - many of which have not yet been classified - live within this coral reef. New Caledonia encloses a 1.500 km circular lagoon and reaches an average depth of 25 meters. In 2008, UNESCO included it among the World Heritage Sites, giving it the name of "Lagoons of New Caledonia".

4 - Mesoamerican Reef, Yucatán, Belize, Guatemala and the islands of the Honduras Bay

The Mesoamerican Reef, located in the Caribbean basin is the largest coral reef in the Atlantic Ocean. The coral reef extends almost 1.126 km, from the Yucatan Peninsula to the Bay of Islands, in Honduras. Over 500 species of fish and 65 types of coral live within this large reef system. It has been a UNESCO World Heritage Site since 1996.

5 - Coral reef of the Maldives Islands, Indian Ocean

The Maldives are the largest coral reef system in the entire Indian Ocean.
The islands that make up the atoll are formed by volcanic eruptions and contain more than 1.300 coral reefs.

6 - Apo Coral Reef, Philippines

The Apo Reef is the largest barrier in the Philippines. This barrier is 800km long and covers 67,877 acres off the coast of Mindoro Island and is surrounded by a mangrove forest. Due to previous problems, in 2007, the Philippine government enacted a ban on reef fishing to help restore and preserve its pristine nature.

7 - Belize barrier reef, Caribbean Sea

The Belize Barrier Reef is a part of the Mesoamerican Reef system. The reef stretches from Ambergris Caye in the north to Cayes Sapodilla in the south.
This coral reef is protected by the UNESCO program, which deals with the world heritage of humanity.

8 - Saya de Malha, Indian Ocean

Saya de Malha Banks in the Indian Ocean is the largest submerged reef in the world. This ridge connects the Seychelles and Mauritius islands to the Mascarene Plateau. Together with its coral reef, the marine habitat facilitates the life of particular species such as turtle and blue whales.

9 - Andros Reef, Bahamas

The coral reef of Andros, in the Bahamas, stretches for approximately 167 km in length. The island is located along the edge of a ocean trench known as the "language of the sea". This means that the barrier extends downwards, this particularity allows it to reach one depth of almost 2 km.

10 - Florida Keys, United States

The Florida Keys Reef system is thethe only coral reef system in North America. This system extends 160km along the southeastern coast of Florida, from Key Biscayne to the Dry Tortugas. The reef is protected as if it were an underwater state park.

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Coral bleaching and death

In recent years, the symbiotic relationship between coral polyps and algae has been altered by rising water temperatures, which in turn are caused by global warming. For reasons not yet fully known, this is leading to the discoloration of corals as well as their progressive death. According to a study conducted by the James Cook University of Australia, over 90% of the Great Barrier Reef has been affected by the bleaching phenomenon.

Other causes of coral death are insane fishing, tourism, ecological imbalances and pollution.

Curiosities about the coral reef

  • What is the largest coral reef in the world?
    It is the great Australian coral reef, which extends for about 2.300 km
  • Is there a coral reef in Sardinia?
    There are no coral reefs in the Italian territory. The closest is the Red Sea Reef along the coast of Egypt. Among the main places where you can admire it there is Marsa Alam.
  • How long does it take for a coral reef to form? It takes thousands of years and several millions of colonies to form relevant coral structures

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