Why coral?
Corals are invertebrates belonging to a large group of colourful and fascinating creatures called Cnidaria - the flagellates. They vary in a wide variety of colours, shapes and sizes, but together they share the same distinguishing characteristics; a simple stomach with a single mouth opening surrounded by stinging tentacles. Each individual coral animal is called a polyp. Most warm-water corals have a symbiotic relationship with zooxanthellae, a type of seaweed that lives directly in the cells of the host coral. The corals provide it with protection and better conditions for photosynthesis, and the algae gives back in the form of food - up to 90% of what it produces during photosynthesis is passed on to the coral. This allows them to grow rapidly and form calcareous shells. It lives in groups of hundreds to thousands of genetically identical polyps that form a colony. The colony is formed by a process called budding, in which the original polyp literally grows as a copy of itself. The individuals in the lower layers gradually die and new corals grow on top of them.
The rainforests of the sea
You may have heard that coral reefs are called "rainforests of the sea". They have earned this nickname not only because of the huge number of species that live here, but also because of the high productivity they provide. Although they occupy only 0.1% of the ocean floor, they provide habitat for at least 25% of all known marine species. They are an ecosystem in their own right, a wonderful mini-world that is home to millions of animals such as colourful fish, sea urchins, octopuses, turtles, shrimps and other crustaceans.
Coral reefs are also rich in symbiotic relationships between species, honed by millions of years of evolution. Thousands of species can be found on a single reef. For example, a barrier reef contains more than 400 species of coral, 1,500 species of fish, 4,000 species of molluscs and six of the world's seven species of sea turtles. The Coral Triangle - comprising the waters between Indonesia, Malaysia, the Philippines and Papua New Guinea - is the most biologically diverse marine ecosystem on Earth.
More than 800 million people worldwide depend on coral reefs, either directly or indirectly.
Corals are invertebrates belonging to a large group of colourful and fascinating creatures called Cnidaria - the flagellates. They vary in a wide variety of colours, shapes and sizes, but together they share the same distinguishing characteristics; a simple stomach with a single mouth opening surrounded by stinging tentacles. Each individual coral animal is called a polyp. Most warm-water corals have a symbiotic relationship with zooxanthellae, a type of seaweed that lives directly in the cells of the host coral. The corals provide it with protection and better conditions for photosynthesis, and the algae gives back in the form of food - up to 90% of what it produces during photosynthesis is passed on to the coral. This allows them to grow rapidly and form calcareous shells. It lives in groups of hundreds to thousands of genetically identical polyps that form a colony. The colony is formed by a process called budding, in which the original polyp literally grows as a copy of itself. The individuals in the lower layers gradually die and new corals grow on top of them.
The rainforests of the sea
You may have heard that coral reefs are called "rainforests of the sea". They have earned this nickname not only because of the huge number of species that live here, but also because of the high productivity they provide. Although they occupy only 0.1% of the ocean floor, they provide habitat for at least 25% of all known marine species. They are an ecosystem in their own right, a wonderful mini-world that is home to millions of animals such as colourful fish, sea urchins, octopuses, turtles, shrimps and other crustaceans.
Coral reefs are also rich in symbiotic relationships between species, honed by millions of years of evolution. Thousands of species can be found on a single reef. For example, a barrier reef contains more than 400 species of coral, 1,500 species of fish, 4,000 species of molluscs and six of the world's seven species of sea turtles. The Coral Triangle - comprising the waters between Indonesia, Malaysia, the Philippines and Papua New Guinea - is the most biologically diverse marine ecosystem on Earth.
More than 800 million people worldwide depend on coral reefs, either directly or indirectly.