What is the largest reef in the world?

The Great Barrier Reef in Australia as seen from a helicopter.
The Great Barrier Reef in Australia as seen from a helicopter.

By Frances Allen

The Great Barrier Reef comprises 2,900 individual reefs, making it the largest coral reef in the world in addition to largest structure on Earth made by living organisms. It lies off the coast of Queensland, located in northeastern Australia. The kaleidoscopic and colorful reef arrangements are so visually vivid that they can be seen from space.

Great-Barrier-Reef-infographic-The-Super-FinsApproximately 500,000 years old, the Great Barrier Reef and has changed structure over time, resulting in the reef we see today. The Australian Institute of Marine Science cites scientific research that outlines the origin of the current reef. Its first formations occurred during the Last Glacial Maximum. A drastic period of environmental change along with a drop in sea levels happened during this time, influencing the formation of the reef.

Geography and Geology

Stretching more than 1,400 miles (2,300 km), the reef would almost reach from Washington D.C. to Denver. Covering approximately 135,000 square miles (345,000 km), it is roughly half the size of Texas, or the equivalent size of Germany.

At its northernmost point, the Great Barrier Reef reaches the Torres Strait and in the south, Fraser Island. The coral is made up of both hard and soft coral types. These corals are made up of many dead materials from older polyps and animals. Think of these are the fossils of the sea.

Animal Life

The Great Barrier Reef is home to a number of animals. Many types of algae and coral polyps make the reef home. There is an interesting symbiotic relationship between the animals and the reef; while porous coral structures provide small animals and algae protection and security from predators, the algae provide limestone to keep reefs healthy and thriving.

Many endangered species make their home here as well. In 2004, the Great Barrier Reef Marine Park Authority added protected zones. To be classified as endangered an animal population has to significantly decrease in or around the reef.

Environmental concerns

The Great Barrier Reef is a very popular eco-tourism spot with approximately 2 million visitors per year. Although the reef is good for the tourist industry, environmentalists are concerned about this level of traffic violating its fragile and unique ecosystem.

Pollution is also a concern. In 2010, a Chinese coal ship leaked a ribbon of oil into the coral nearly two miles long, destroying marine life and water quality. The Great Barrier Reef Coastal Wetlands Protection Program has also been charged with preventing domestic pollution from synthetic pesticides and fertilizers used in the region.