Coral

Coral diversity

Coral reefs represent only 1% of the world’s ocean surface but contain 25% of marine biodiversity and more than 1/3 of species diversity of fish. Indeed, coral constitute a safety for many species, a nursery for juveniles and more specifically for fish species, and are a food source for corallivore species (species which eat coral), like parrotfishes.

People who live on the coast, especially in Indo-Pacific, are highly dependent of coral reef. If the reef is healthy, it will contain numerous fishes. If not, it will be lacking of fish, and the main food source of these populations will be affected.

The reefs are important for lands protection. It is a shield against strong storms and typhoons.
At the global scale, coral reefs are also very important because they take part of the ocean oxygen production, which can be more than 50% of the oxygen atmosphere that we breath, through their symbiosis with the zooxanthellae.

Fish diversity

What is coral?

Polyps

Coral is part of family of anemones and jellyfish, the Cnidaria phylum, so coral are animal (and not rock or vegetal like it looks like). They are commonly divided in two kind: hard coral, Scleractinian, and soft coral.
First, Scleractinian are form by polyps, living in a colony and secreting calcium carbonate skeleton. Consequently, hard coral is considered as a reef building organism, constitute coral reef and are at the origin of Atolls.

                                       Coral=polyps+calcareous skeleton.

There is numerous kind of coral skeleton form and polyps, that define the different species. More than 800 different species have been identified all around the world. Depending the species, coral grows slowly, between 1 to 10 cm per year.

 

 

 


 

Corals are 10% « carnivore » and 90% « vegetarian ».

Corals live in symbiosis with microscopic algae, called Zooxanthellae.
Zooxanthellae produce energy via photosynthesis process and transfer 90% to the coral tissue. In return, these algae are protected inside the polyps and assimilate some nutrients excreted by their host. Photosynthesis take place exclusively during the day, then during the night, polyps deploys their tentacles (where stinging cells are located, the cnidocysts) for capture particles in the water.

 

 

 

 

 

 

 

 

 

 

 


 

The Coral and its color.

Originally coral has no color. Its color come from the density of zooxanthellae present inside its tissues, which can vary between 0.5 and 5 million cells per m².
But, if coral is subject to stress, the symbiosis with the zooxanthellae will be broken, leaving the coral « white » . Then, coral will lose most of its energy source, and can survive only for a short period. If environmental conditions still not favorable to the return of zooxanthellae, the coral dies, and filamentous algae will take its place.

Coral Alive

Bleached Coral

Destroyed Coral

 

 


 

Factors of stress.

  • Raise of water temperature.
  • High irradiance.
  • Lack of light.
  • Water acidification, induced by increase of atmospheric CO₂.
  • Pollution by pesticide, herbicide and heavy metals, carried to the sea via land-runoff and rivers.
  • Bacterial infections and or virus.

Despite the global phenomenon of coral bleaching, it’s not too late to act.
For this reason, Sulubaai Environemental Foundation reacts in rebuild reefs completely destroyed by human.
Help us and take action with a donation. With 40€ and more, Sulubaaï Environmental Foundation will implant one or more SRP in degraded reef area in the Philippines, at your name. Your donation will finance the SRP building, coral implantation and coral reef survey. Each year, you will received a picture of your SRP reef to follow your coral growth and involving.

Destroyed Coral