Palau Coral Reef
Coral reefs are one of the most complex and colorful tropical
ecosystems, rivaling rain forests in their richness of life. Coral
reef organisms build massive & intricate physical structures that are
home to some of the most fascinating plants and animals in the world.
Their extraordinary beauty captivates visitors and their productivity
provides a wealth of resources for local communities and the world.
What is a coral reef?
Coral reefs are massive structures made of limestone that is deposited
by living things. Although thousands of species inhabit coral reefs,
only a fraction produce the limestone that builds the reef. The most
important reef building organisms are corals.
Coral reefs support over twenty-five percent of all known marine
species. As one of the most complex ecosystems on the planet, coral
reefs are home to over 4,000 different species of fish, 700 species of
coral and thousands of other plants and animals.
A good way to imagine a coral reef is to think of it as a bustling
city or community, with the buildings made of coral, and thousands of
inhabitants coming and going, carrying out their business. In this
sense, a coral reef is like a metropolis under the sea.
What is coral?
Although coral is often mistaken for a rock or a plant, it is actually
composed of tiny, fragile animals called coral polyps. When we say
"coral" we are actually referring to these animals and the skeletons
they leave behind after they die.
Although there are hundreds of different species of corals, they are
generally classified as either "hard coral" or "soft coral".
Hard corals grow in colonies and are the architects of coral reefs.
They include such species as brain coral and Elkhorn coral. Their
skeletons are made out of calcium carbonate (also known as limestone)
which is hard and eventually becomes rock. Hard corals are hermatypes
or reef-building corals and need tiny algae called zooxanthellae
(pronounced zo-zan-THEL-ee) to survive. Generally, when we talk about
"coral" we are referring to hard corals.
Soft corals such as sea fingers and sea whips are soft and bendable
and often resemble plants or trees. These corals do not have stony
skeletons, but instead grow wood-like cores for support and fleshy
rinds for protection. They are referred to as ahermatypes or non-reef
building corals and they do not always have zooxanthellae. Soft corals
are found in both tropical seas and in cool, dark regions.
Where do corals live?
Coral reefs are found in over 100 countries. Most reefs are located
between the tropics of Cancer and Capricorn, in places such as the
Pacific Ocean, the Indian Ocean, the Caribbean, the Red Sea and the
Arabian Gulf. Corals are also found farther from the equator in places
where warm currents flow out of the tropics,...