Corals are the world's leading animal in creating physical structures, such as Australia's Great Barrier Reef. The world's largest coral reef covers about 133,000 square miles and is visible from outer space. That is a big project for a bunch of tiny animals without backbones. This huge reef was created by colonies of these spineless animals during the past 20,000 years.
Although corals may look like brightly colored plants, they are small animals consisting of a hollow stem with a stomach inside and a ring of tentacles on the top surrounding their mouth. Most corals are able to create a stony skeleton by taking calcium out of the water. Over thousands of years, this stony skeleton grows with the colony of these tube-like coral polyps living on the top.
Related to jellyfish and anemones, these animals may have stinging cells in their tentacles, which help them to capture small animals for food. Many corals also get food from algae cells living inside them. This is why most coral reefs are typically found in sunny and shallow waters. Algae needs a lot of sunlight to produce enough food for itself and its coral host. Some corals, however, do not have algae to help provide food. These species can be found in darker and colder areas, with some as deep as almost 10,000 feet.
Unfortunately, corals worldwide are in trouble. At least 10 percent have died in the past 20 years from environmental and human-influenced effects. Up to 80 percent of corals are in danger. Reefs provide not only a home to thousands of other animals, but also have the potential for scientific discovery.
Carnegie Science Center has donated coral it grew to scientists at Rutgers University. They are using them to help discover a cure for cancer. You can see a variety of corals, and our cancer research helpers, when you visit our live reef tanks.
First Published October 9, 2013 8:00 PM