The only animal
that has built a structure
visible from space
of marine life call coral reefs their home, while covering less than 1% of the ocean floor.
of the oxygen we breathe is produced by the ocean through among all coral’s symbiotic algae and other marine organisms.
people worldwide directly rely on the reef for food, income, coastal protection and more.
is generated each year by tourism directly related to coral reefs.
corals are complex
What are they?
They are colonial organisms made of thousands of individual animals called polyps. Each polyp has a mouth surrounded by a whorl of tentacles.
What about their symbiotic algae?
Corals live with symbiotic algae called zooxanthellae, present within their tissues. The polyps provide protection for zooxanthellae, that give in return energy to the hosts through photosynthesis.
How do they feed?
Corals mostly feed from within, from the food created by their symbiotic algae or by capturing food that drift by their polyps’ tentacles.
How do they build reefs?
Polyps are able to transform seawater into a house of calcium carbonate, their permanent skeleton. The polyps all build their houses of calcium next to each other, expanding colonies like an underwater city.
are in danger
Rising water temperatures
The risk of facing bleaching events is increasing and alarming. When the seawater temperature rises, it can upset the symbiosis between the coral polyp and its algae. The algae become toxic for the polyp which therefore expels it. Without the algae, corals lose its main source of food and its color turning skeletal white. If the conditions don’t improve, corals are likely to die. The warmer our climate gets, the more likely the coral will bleach and die.
The ocean absorbs around 30% of the carbon dioxide (CO2) of the atmosphere. The more CO2 the atmosphere releases, the more acidic the ocean becomes. The rising acidity of the ocean makes it harder for the corals and other marine organisms to form and properly build their calcium carbonate skeleton. This situation makes them more vulnerable.
Half of the world’s coral reefs have already been lost or severely damaged. If nothing is done, coral reefs will be the first ecosystem on Earth to entirely collapse, dragging with it the loss of 25% of marine life that rely on them.