RP212 The Great Wall of the Ocean

 RP212 The Great Wall of the Ocean

Skirting the coast of northeast Australia is the only living thing that can be seen from space. The Great Barrier Reef runs alongside Queensland for 2,600 kilometers, providing food and shelter for a huge variety of plants and animals, many of which are endangered. Only tropical rain forests house as many species as the Reef does.

The Great Barrier Reef is the longest coral reef in the world, but it isn't all one mass. It's made up of 2,900 or more separate reef systems, which combine to make one long, interconnected whole. Four hundred species of hard and soft coral make up the body of the Reef. Bright, living coral grows on top of the skeletons of the old. The current Reef is estimated to be about 20,000 years old. When the Reef began growing, sea levels were much lower. As sea levels rose, new coral climbed higher, but coral underneath died. coral needs sunlight to live, and light can only penetrate water to a certain depth.

Among all this coral are plants, snails, whales, sharks, jellyfish, and other sea creatures. Six endangered species of sea turtle live in the Reef, laying their eggs on nearby sandy shores. Humpback whales migrate there every winter, and since whaling ended in 2008, their numbers are increasing. The dugong, or sea cow, lives there, grazing on fields of sea grass. These mammals are in danger of extinction, and are one of the many protected animals who make the Reef their home.

Despite its huge size, the Reef isn't invulnerable. Rising ocean temperatures are dangerous to coral and some fish. Pollution from farms reduces the water quality and promotes the growth of algae, which blocks the light. Shipping accidents have done major damage. Predators cause trouble. The crown-of-thorns starfish eats coral. Its recent population boom put the entire Reef at risk.

Constantly growing, constantly dying, this great wall relies on a complex ecological balance. We should guard it carefully.