The Great Barrier Reef is an ocean ecosystem that can be seen from space. Estimated to have existed for 250 million years, the Great Barrier Reef and its multitude of marine life are immersed in a challenge that has the entire system on the brink of extinction. Coral reefs are living organism that support other life forms. Corals are animals, tiny polyps with individual genetic identity.
According to Daily Galaxy, corals defend, and kill and eat plankton. Corals secrete calcified deposits that are the basis of more coral reefs. The process takes enormous periods of time. A coral ecosystem can host over 4000 life forms. According to Daily Galaxy, the Great Barrier Reef is a complex ecosystem with more than 2900 reefs. According to National Geographic, the reef's shallow coastal waters are the the tropical home to biodiversity rivaling the world's tropical rainforests. But the world's reefs, like the world's rainforests, are declining. The Great Barrier Reef is not the only coral ecosystem endangered. All of the world's coral reefs are struggling to survive. The Christian Science Monitor reported in early 2009 that growth of the coral in the Great Barrier Reef is slowing. Calcification, necessary for coral growth, is falling, according to a study published in the journal, Science (2009).