Set off the coast of Queensland in the Coral Sea, the Great Barrier Reef, extends for 2700 km and covers an area of 348,700 km² (that is bigger than Italy), it consists of 2,900 individual reefs, 600 different coral species making up 1/3 of the world’s coral, 300 coral cays, and 160 inshore mangrove islands. Thus creating one of the most diverse ecosystems in the world and a haven for 30 species of whale, dolphin, and porpoise, 6 species of turtle, more than 1,500 species of fish and because we are in Australia, 17 species of sea snake!
So, what is a coral? It is made of millions of little soft bodied polyps with extended tentacles that protect themselves by secreting a hard outer skeleton made of calcium carbonate. They attached themselves to rock or other dead coral skeletons. They can exit as individual units or create hard coral colonies which forms the backbone of the Great Barrier Reef. The colours of the coral are attributed to the algae found within, called zooxanthellae. This hard coral can grow at an average of 1.27 cm per year.
The Great Barrier Reef is the single largest structure built by living organisms.