The Great Barrier Reef is the largest, most complex, and most diverse coral reef system in the world. It is comprised of over 2,900 individual reefs and 900 islands stretching for more than 1,600 miles (2,600 km) across an area of approximately 133,000 square miles (344,400 square km). The reef is home to over 1,500 species of fish, 400 species of coral, 500 species of seaweed, 200 species of birds, and many rare and endangered species. It also hosts dugongs, six of the world’s seven species of marine turtles, whales, dolphins, and porpoises.
The Great Barrier Reef can be seen from outer space and is the world’s biggest single structure made by living organisms. The reef structure is comprised of and built by billions of tiny organisms known as coral polyps. It supports a broad diversity of life and was selected as a World Heritage Site in 1981. A large part of the reef is protected by the Great Barrier Reef Marine Park, which helps limit the impact of human use, such as fishing and tourism.
As Louise Goggin notes in her article “The Great Barrier Reef: Will It Still Be Great Next Century?”:
The Great Barrier Reef has many features that help to protect it, giving it a natural advantage over some other reef systems around the world (Maniwavie, et. al., 2000; Reichelt, 2001).
- Many of its 2,900 individual reefs are well offshore and remote from major runoff and pollution from the land, as well as from easy access by the adjacent population.
- The population density along most of the neighboring Australian coastline is relatively low compared with reefs overseas.
- Australians do not depend on the Great Barrier Reef for subsistence fishing. In addition, destructive fishing practices such as blasting and poisoning are extremely rare if not absent in Australia.
- The Great Barrier Reef is a huge area with a relatively low level of human use.
- The Great Barrier Reef has been protected and managed within the Great Barrier Reef Marine Park since 1975. An extensive zoning system exists with a review of no-take zones currently underway.
- The Great Barrier Reef is one of the best-studied coral reef ecosystems in the world with probably the largest and most extensive monitoring programs (which are used as models for projects overseas).
These features do not guarantee the reef will remain in a healthy state into the future. The Great Barrier Reef is currently under threat from pressures from adverse water quality, as well as significant medium to long-term threats from global warming. In Australia, increasing populations adjacent to the Great Barrier Reef, and increasing pressure from unsustainable fishing and tourism impacts in specific high use areas, will need to be managed.
Global warming threats to the reef include coral bleaching and ocean acidification. Coral bleaching refers to the loss of zooxanthellae in corals, resulting in a loss of pigmentation (color). It can impact coral growth and make the coral more vulnerable to disease. In 1998 and 2002, major bleaching events occurred in parts of the Great Barrier Reef, causing a significant die-off of corals in some locations.
Ocean acidification refers to changing water chemistry. It affects such things as the formation of calcium, which organisms with shells rely on. Acidification could have a major detrimental impact on coral reefs such as the Great Barrier Reef.
The Earthducation team will be visiting several Great Barrier Reef communities in northeastern Queensland, and will finish up their travels with an overnight on a boat at the outer reef, several hours offshore from Magnetic Island.
National Geographic introduction to the Great Barrier Reef. National Geographic also offers an interactive map of the Great Barrier Reef.
Great Barrier Reef video with nice underwater footage.
“What Is Coral Bleaching?” is an informational video put together by the Great Barrier Reef Marine Park Authority. The Reef and Rainforest Research Centre in Australia has produced a nice video introduction to coral bleaching as well.
Acid Test: The Global Challenge of Ocean Acidification is a short (20-minute) documentary that explores the phenomenon of ocean acidification. Narrated by Sigourney Weaver.