A short essay about corals.

Essay by sunandmoon July 2006

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Tropical seas are renowned for their variety of colour and fascinating marine life. Coral reefs have a unique place in this aquatic world and indeed their surrounding environment. Despite its "plant like" appearance, coral is actually a marine animal of the invertebrate species having no spinal columns, like jellyfish. Coralreefs are sensitive ecosystems, which are under treat from human and natural elements alike. Reefs have formed over millions of years, and their scientific study teaches us many things about the complex changes that our environment has undergone through the ages. Coralreefs are indeed an invaluable living record of our natural history , a snapshot in time.

The body of the coral consists of a polyp - a hollow, cylindrical structure which attaches its lower end to a surface. The free end is a mouth which gathers food and acts as a "stinger" paralysing unsuspecting prey. The continual growth of new buds, or developing polyps, cause the old ones underneath to die.

The sceletons remain, however, creating a colony of corals, later developing into a reef. It is this fragile structure which forms an essential natural filter which removes detritus impurities, providing a clean habitat for marine plants and animals.

Reefs grow faster in clear water and in the warm temperatures of tropical oceans are generally found at depths less than 46 metres, where sunlight penetrates, a necessary condition for corals to thrive and grow. Waves also carry food, nutrients and oxygen to the reef. Shallow, warm , tropical waters with strong wave action are ideal conditions for these unique organisms to flourish.