Coral reefs


The coral reefs are among the ecosystems most diverse we can find the way around in the world, which have the capacity to accommodate tens of thousands of different marine species . About a third of all marine fish species live part of their lives on coral reefs.


What are coral reefs?

A coral reef is a structure made of stone limestone has the capacity to provide shelter much of the marine life in addition to creating a barrier against the erosion that occurs on the coasts.

  • Coral reef characteristics
  • Types
  • How they are formed
  • Where they are
  • Flora
  • Fauna
  • Weather
  • Function
  • Profits
  • How climate change affects coral reefs
  • Whitening
  • Contamination
  • How to protect coral reefs
  • Importance
  • Coral reefs in the world

Coral reef characteristics

Among the main characteristics of coral reefs we can mention the following:

  • They are located in shallow waters .
  • They need warm temperatures to survive.
  • Hard coral reefs have limestone skeletons while soft ones leave no traces.
  • They have three important areas: the one near the sea or in front , the crest or reef plateau and the area closest to the shore .
  • They are formed by solid structures of calcium carbonate .
  • They thrive in tropical waters .
  • They are located between the Tropic of Cancer and the Tropic of Capricorn .
  • It is one of the environments most ancient land.


There are three different types of coral reefs:

  • Boundary reefs : they are the most common and are located adjacent to the coasts of islands or continents.
  • Barrier reefs : they are located parallel to the coast but are separated from the shore by a fairly deep lagoon . An example is the Great Barrier Reef off the northeast coast of Australia .
  • Atolls : they are located above submerged volcanoes and have a fairly circular shape with an interior lagoon .

How they are formed

The first step for a coral reef to form is to have plenty of sunlight , clear water , and a temperature above 18 degrees Celsius. It requires photosynthesis, which is carried out by zooxanthellae , algae that live in symbiosis with the animal and are responsible for the color of corals. To reproduce, corals multiply per shoot, eventually forming a colony , which can last several years.

At certain times, in adult colonies , eggs and sperm are expelled into the water to give rise to fertilization and give rise to new plants that will end up forming new polyps . After thousands and thousands of years, the reef matures, and the marine biodiversity begins to live around it.

Where they are

They generally thrive in warm , clear, and calm waters . Its distribution depends on the water temperature , depth , light intensity , salinity , turbulence and sedimentation . They are in places where the temperature is between 20 and 28º C and at a depth of 25 meters or less, which is considered the ideal.

The largest number of them are found in the area of Australia , Southwest Asia and the Pacific . They can also be found off the coast of Florida in the United States, along the Caribbean , and along the coast of Brazil .


Plant life of coral reefs is quite large and is in fact considered as one of the biomes of higher productivity . Its main plant is algae and they are also in charge of giving the reef its color . The algae fulfill their function of preventing and avoiding their contamination .


In them we can find a great variety of fauna, creatures such as sponges, fish, jellyfish, crustaceans , snails, turtles and mollusks . Many birds live near coral reefs because it is very easy for them to access fish and other organisms for food . You can be found invertebrates such as sea urchins and sea more than 4000 species of fish , sea snakes, some reptiles and snakes semiaquatic.


For coral reefs to survive and develop, the water temperature needs to be between 20º and 28º Celsius , a climate that can be found in areas located between the Tropic of Cancer and the Tropic of Capricorn .


One of the functions of coral reefs is to form a biome with special characteristics depending on the life forms that inhabit them. The reefs are complex ecosystems, which also have the function of being trainers of white sand beaches and tropical islands are of great importance to prevent erosion of the beaches , and to protect us from strong waves during heavy storms and hurricanes .

They also help capture carbon dioxide from the atmosphere by fixing it in their skeletons, favoring the generation of hundreds of marine organisms , and being a source of food, they are essential for the formation of food webs .


The reefs are a great tourist attraction , as they are one of the most beautiful marine landscapes on the planet, so they are a source of economic income for many places. They protect things against erosion , they are the habitat of many marine species and they are also a source of natural chemical compounds ; they also promote scientific research .

How climate change affects coral reefs

Scientific evidence tells us that both the atmosphere and the ocean are warming , and that these changes are mainly due to greenhouse gases that are the result of human activities .

As temperatures increase, they will whiten the corals massively and shoots arise infectious diseases . Furthermore, the carbon dioxide that is absorbed into the ocean from the atmosphere reduces the rates of calcification in building reefs and organisms associated with reefs are affected altering the chemistry of the water of the sea by a decrease in pH . This process is known as ocean acidification .

Climate change will also affect coral reef ecosystems by the elevation of the level of the sea , changes in the frequency and intensity of tropical storms and the alteration of patterns of ocean circulation . All of these aspects dramatically alter the function of the ecosystem , as well as the goods and services that coral reefs provide to the world.


The bleaching of coral reefs is a process that has greatly affected them and is due to a process called bleaching or bleaching . This process occurs due to the increase in the temperature of the oceans since as the sea is warmer, the algae , which live symbiotically with the coral, abandon the coral that hosts them. As these algae provide nutrients and color to the coral, when it runs out of them, it becomes bleached or discolored, causing the death of the reef .


The global warming , the acidification of the oceans, pollution from sewage and garbage , the industrial fishing , some types of invasive species such as lionfish and deforestation of forests are the main causes of pollution that threaten the conservation and life of coral reefs.

The high erosion and irresponsible tourism are factors that threaten the conservation of coral reefs, also adding industrial or trawling fishing , because this type of fishing drags everything that is on the seabed.

How to protect coral reefs

There are several ways to protect coral reefs, among them we mention the following:

  • Reducing the size of the carbon footprint to reduce greenhouse gases.
  • With reduction , reuse or recycling .
  • Obtaining information about how to dive in coral reefs.
  • Participating in beach and seabed cleaning .
  • Not throwing garbage into the seas.
  • Reducing the environmental pollution in general.


Coral reefs are important because they protect the coasts against erosion and the pounding of waves, they are the habitat for many marine species, including those for human consumption, and they are of great importance for fishing .

Coral reefs in the world

  • Honduras : here we find one of the richest on the planet, Roatán . There are 167 species of reef fish identified and it has two of the most important types of seagrass , turtle grass and manatee grass.
  • Puerto Rico : among the most extensive are those in the west, such as Margarita , on the coast of Cabo Rojo and those in the flat waters around Mona Island . There are also coral reefs on the southwest coast, from Guánica to Caja de Muertos Island , on the south coast. Several scientific institutions in Puerto Rico and the world have carried out very important scientific investigations in the reefs of La Parguera in Lajas , and in the Cordillera de Fajardo .

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