Great Barrier Reef
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in the south to the most
northern tip of Queensland . It is the
world’s largest coral reef ecosystem with 70 ‘bioregions’ and an astounding biodiversity. 
History
In 2007, it was also placed on Australia’s National Heritage List.
While the park is managed by the Great Barrier Reef Marine Park Authority, it does so in conjunction with the Government of Queensland and the reef’s traditional owners - more than 70 clans of Aboriginal and Torres Strait Islander people who are the indigenous people of Australia. It is thought that their arrival in Australia dates back 40,000 years and that they fished and hunted throughout the waters of the Great Barrier Reef in outrigger canoes. Indigenous cultural sites include middens and elaborate rock paintings that are found on many islands within the park.
Captain James Cook was one of the first Europeans who struggled to navigate the reef’s waters in the 18th century and around 30 shipwrecks of historical significance are testament to the challenge it provided to early explorers.
The reef is thought to date back as many as 20 million years with generation after generation of living coral dying and compacting into great stone walls upon which new corals, sponges, and anemones grow, providing a home to the vast array of marine species that have evolved. The reef’s growth has been interrupted by the Ice Age and low sea level events, with the current growth dated to around 8,000 years ago. Coral cores indicated when sea levels dropped during glacial periods, the reef was exposed as limestone hills before sea levels again rose, forming islands, cays and new coral growth.
Flora and Fauna
Hard corals provide the support structure for the reef and are formed when coral polyp colonies form supportive limestone skeletons. In contrast, soft corals are more flexible and fluid, with jelly-like tentacles supported by limestone spicules. Their brightly colored branches provide homes to many species of fish, prawns, and sea slugs. To deter predators, soft corals often secrete poisonous chemicals that make them inedible.In addition to the 600 soft and hard corals that structure the reef, the park also includes 2,000 square kilometers of mangroves and 6,000 square kilometers of seagrass beds. Both of these ecosystems are integrated with the reef, filtering water, and providing protected areas for fish to breed, and are vital for the reef’s survival.
While it is famous for it’s diverse array of colorful fish, the reef is also home to 3,000 different types of Mollusc, 630 species of Starfish and Urchins, 133 varieties of Sharks and Rays, more than 30 species of Whales and Dolphins, 6 species of Marine Turtles, as well as deadly Crocodiles that peruse the waters and Seabirds that roam the skies.
The Great Barrier Reef is home to a number of endangered species that are heavily protected by the Great Barrier Reef Marine Park Authority. Six of the world’s seven endangered sea turtle species are found in the park, along with the Dugong, or Sea Cow, that grazes on seagrass beds. Its slow breeding rate makes it particularly vulnerable. The world’s largest sea mammal, the endangered Blue Whale, also migrates through the Great Barrier Reef's waters
Snorkeling and Diving
The Great Barrier Reef is one of Australia’s premier tourist destinations with 2 million tourists each year, generating around $3 billion USD. It is one of the greatest snorkeling and diving locations in the world with water temperatures between 24°C and 30°C (80°-90° Fahrenheit) and visibility of up to 30 meters. Popular sites include Ribbon Reef, Osprey Reef, Heron Island, and the SS Yongala wreck. The reef can be visited aboard dive boats or day charters from a number of major centers, including Cairns and Townsville. There are a number of PADI accredited dive shops that offer training and equipment hire throughout the reef.For non-divers, there is also excellent snorkeling within walking distance of some of the country’s best beaches. Great Keppel Island
, Langford
Island and Haslewood Island all offer great opportunities to get up close and personal with the area's
marine life, without having to take a tank. Glass-bottomed boats and underwater observatories are also popular options
for those that prefer not to get wet, while helicopter flights are available to view the reef’s extent from the air.
Ecologically sustainable tourism is encouraged within the park with boat numbers limited and tourists educated on the reef’s importance and how they can help protect it.
, such as Josephine Falls and Wallaman Falls, make for interesting day
trips, as do the explosion of ‘big’ sculptures that are features of Australian country towns along the coast. A
number of zoos and parks nearby also offer the opportunity to get up close and personal with Australia’s native
wildlife, including koala cuddling and snake holding.
Climate Change
Climate change is the biggest threat to the Great Barrier Reef’s survival with rising sea temperatures and levels, together with ocean acidification (caused by an increased uptake of carbon dioxide), hazardous to the delicate balance of this ecosystem. The reef experienced severe coral bleaching events in 1998 and 2002, linked to El Nino and abnormally high sea-surface
temperatures. Under such conditions, corals may expel their zooxanthellae which are responsible for giving coral their
coloration. Ongoing sediment, nutrient, and pesticide run-off from onshore farming activities and flood events have
resulted in algal blooms and the Crown-of-Thorns Starfish epidemic that has been highly destructive in recent years.
These densely-spined animals feed on coral and, under normal conditions, regulate coral growth. However, when numbers
increase dramatically as a result of increased nutrients, their grazing can leave large expanses of reef bare. Current government plans to increase shipping through the reef, with the world’s biggest coal port at Abbott Point in close proximity, also has the potential to cause irreparable damage to the reef, particularly if accidental oil spills occur. This is a highly controversial topic amongst conservation groups and the wider Australian public.
Overfishing has also resulted in a decline of fish species in recent years, prompting an increase in designated off-limit areas to allow stocks to recover.
While the Great Barrier Reef is a highly sensitive area exposed to significant tourism activity and human-induced pollution, conservation groups, landholders, scientists, and government agencies are working in close collaboration to ensure its survival for future generations.
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Author: Pip23. Last updated: Feb 17, 2015
Pictures of Great Barrier Reef
