Instruct: Given a question, retrieve passages that can help answer the question.
Query: How much of the Great Barrier Reef is bleached?
Elevated sea water temperatures are the main cause of mass bleaching events. Sixty major episodes of coral bleaching have occurred between 1979 and 1990, with the associated coral mortality affecting reefs in every part of the world. In 2016, the longest coral bleaching event was recorded. The longest and most destructive coral bleaching event was because of the El Niño that occurred from 2014–2017. During this time, over 70% of the coral reefs around the world have become damaged.
The total land mass of Queensland covers 22.5% of the Australian continent, an area of 1,730,648 square kilometres, making it the second largest state in the Commonwealth of Australia. The total length of Queensland's mainland coastline is with another of island coastline. A unique geographical feature of the state is the Great Barrier Reef, an important tourist drawcard. The Tropic of Capricorn crosses the state with about half of Queensland's area located to the north of the line.
Queensland contains significant areas of rainforest and other areas of biological diversity. World Heritage Areas include the Great Barrier Reef, Wet Tropics of Queensland and Gondwana Rainforests of Australia. Queensland has 226 national parks. The largest is Simpson Desert National Park in the remote central west of the state. The most visited national parks in South East Queensland are Tamborine National Park, Lamington National Park and Noosa National Park. These parks are located near centres of major population and are the most accessible in the state. Lamington and other parks around the Scenic Rim such as Main Range National Park, are included in the World Heritage listed Gondwana Rainforests of Australia.
The Houtman Abrolhos is unusual in having a luxuriant and diverse living coral reef at such a high latitude. 194 species in 50 genera have been recorded there, all but two of which are tropical. This is a surprisingly high coral diversity, considering the high latitude of the reef, and the relatively low diversity of other biota. For a full list, see list of corals of the Houtman Abrolhos.
Plastic debris tends to accumulate at the centre of ocean gyres. The North Pacific Gyre, for example, has collected the so-called "Great Pacific Garbage Patch", which is now estimated to be one to twenty times the size of Texas (approximately from 700,000 to 15,000,000 square kilometers). There could be as much plastic as fish in the sea. It has a very high level of plastic particulate suspended in the upper water column. In samples taken in 1999, the mass of plastic exceeded that of zooplankton (the dominant animal life in the area) by a factor of six.
The largest national park in the world is the Northeast Greenland National Park, which was established in 1974 and currently protects
Crown-of-thorns starfish ("Acanthaster planci") is the major predator of the reefs, as it preys upon coral polyps by climbing onto them, extruding its stomach over them, and releasing digestive enzymes to absorb the liquefied tissue. An individual adult can eat up to 6 m of reef per year. In 2000, an outbreak of crown-of-thorns starfish contributed to a loss of 66% of live coral cover on sampled reefs. Changes in water quality and overfishing of natural predators, such as the Giant Triton, may have contributed to an increase in the number of crown-of-thorns starfish.
The marine waters of the Houtman Abrolhos, an island chain off the coast of Western Australia, have been recorded as containing 194 species of coral in 50 genera. This is a surprisingly high coral diversity, considering the high latitude of the reef, and the relatively low diversity of other biota. This is a list of corals of the Houtman Abrolhos:
The patch is not easily seen from the sky, because the plastic is dispersed over a large area. Researchers from The Ocean Cleanup project claimed that the patch covers 1.6 million square kilometers. The plastic concentration is estimated to be up to 100 kilograms per square kilometer in the center, going down to 10 kilograms per square kilometer in the outer parts of the patch. An estimated 80,000 metric tons of plastic inhabit the patch, totaling 1.8 trillion pieces. 92% of the mass in the patch comes from objects larger than 0.5 centimeters.
The marine waters of the Houtman Abrolhos, an island chain off the coast of Western Australia, are unusual in containing a mix of tropical, subtropical and warm-temperate fish species. This mix is largely due to the Leeuwin Current, which brings warm tropical water to the Houtman Abrolhos, especially in winter. Tropical species are the most abundant, eleven of the sixteen most abundant species being tropical fishes. However, there are also a large number of tropical species with populations so small that they are thought not to maintain populations be breeding at the Houtman Abrolhos.
Madagascar lies entirely in the Indian Ocean Whale Sanctuary, a whale sanctuary that covers the Indian Ocean south to 55º S. The sanctuary prohibits commercial whaling and aims to facilitate the recovery of whale populations, allow whales to do their jobs within the ecosystem, and foster public awareness. This sanctuary’s conservation efforts are uniquely important for several reasons. The sanctuary allows for the Sperm whale and the Oman Humpback whale to recover their population which has been diminished by illegal soviet whaling operations in the 70’s. The sanctuary also allows the population recovery of the Bryde’s whale from Japanese whaling operations which still continue to this day as Japan does not respect the sanctuary and continues its operations claiming that their operations are purely scientific. Approximately 600 whales are killed each year by Japanese scientific whaling operations.
Coral in the south Red Sea does not bleach despite summer water temperatures up to .
Coral bleaching in the Red Sea is more common in the northern section of the reefs, the southern part of the reef has been plagued by coral eating starfish, dynamite fishing and human impacts on the environment. In 1988 there was a massive bleaching event that affected the reefs in Saudi Arabia and in Sudan, the southern reefs were more resilient and affected them very little. Previously it was thought that the North suffers more from coral bleaching but they show a fast turnover of coral and the southern reef was thought to not suffer from bleaching as harshly, they show more consistency. However, new research shows where the south reef should be bigger and healthier than the north it was not. This is believed to be because of major disturbances in recent history from bleaching events, and coral eating starfish.
In 2010, coral bleaching occurred in Saudi Arabia and Sudan, where the temperature rose 10 to 11 degrees. Certain taxa experienced 80% to 100% of their colonies bleaching, while some showed on average 20% of that taxa bleaching.
One population, possibly genetically distinct, lives in the Northern Hemisphere and has stranded from Nova Scotia in the western Atlantic to Ireland in the eastern Atlantic and as far south as Florida, the Bahamas, and Canary Islands. Another population lives in the Southern Hemisphere and has stranded in South Africa, New Zealand and Australia. The species does not inhabit the Southern Atlantic or Northern Indian Ocean, and appears to avoid tropical waters. No population estimates have been established, but it is believed to be one of the rarest species of whale.
An autonomous starfish-killing robot called COTSBot has been developed and as of September 2015 was close to being ready for trials on the Great Barrier Reef. The COTSbot, which has a neural net-aided vision system, is designed to seek out crown-of-thorns starfish and give them a lethal injection of bile salts. After it eradicates the bulk of the starfish in a given area, human divers can move in and remove the survivors. Field trials of the robot have begun in Moreton Bay in Brisbane to refine its navigation system, according to Queensland University of Technology researcher Matthew Dunbabin. There are no crown-of-thorns starfish in Moreton Bay, but when the navigation has been refined, the robot will be used on the reef.
Swells dropped to 1–1.5 m on 28 June 2011, allowing more netting of sardines. Sardines were netted at Amanzimtoti; on the main beach and at Chain Rocks. A 22-year-old American marine biology student (research diver) named Paulo Edward Stanchi was attacked by a large dusky shark while diving at Aliwal Shoal Marine Protected Area. The group of divers had encountered a pocket of sardines when a 3 m long dusky shark bit Mr Stanchi on his left leg and hands. Mr Stanchi managed to free himself from the shark, and was treated on the diving boat before being transported to Rocky Bay, where medics stabilised him. He was then airlifted to Nkosi Albert Luthuli Hospital, where he underwent surgery. Dusky sharks generally live offshore, but come closer to the shore during the sardine run. The annual sardine run allowed more dusky sharks in the Aliwal Shoal MPA than usual, but there was no reason for them to show any more interest in divers than usual. Mr Stanchi had been wearing split fins with black and grey stripes, and this may have looked like a small shoal of fish to the shark. Meanwhile, a woman in her 40s broke her leg in the frenzy at Amanzimtoti when the sardines were netted. The woman is believed to have been trying to get some of the sardines when she "stepped wrong" and fractured her leg. Paramedics stabilized her before transporting her to hospital.
The island is known for its diversity of mammalian fauna, including several species now extinct or greatly reduced on mainland Australia. 13 mammal species exist on the island, including the spectacled hare-wallaby, burrowing bettong (or boodie), golden bandicoot, black-flanked rock-wallaby, Barrow Island euro and Barrow Island mouse ("Pseudomys nanus ferculinus"). The island is also home to 43 species of terrestrial reptiles including a variety of dragons, legless lizards, geckos, skinks, snakes and monitors. The most recognisable of these is probably the perentie, Australia's biggest lizard and the island's top predator. The island represents important turtle nesting habitat for the green turtle and flatback sea turtle.
The Bhitarkanika Mangroves are home to 55 of India's 58 known mangrove species. The mangroves harbor one of India's largest populations of saltwater crocodiles, and Gahirmatha Beach, which separates the mangroves from the Bay of Bengal, is the world's most important nesting beach for olive ridley sea turtles. Some wildlife experts are of the opinion that the largest saltwater crocodile ever was in Bhitarkanika, measuring an estimated 23 feet (7.0 m) which could be traced from the skull preserved by the Kanika Royal Family. The crocodile was shot near Dhamara in 1926, and later its skull was preserved by the then Kanika King. Crocodile experts estimate the animal to have been between 20 feet (6.1 m) and 23 feet (7.0 m) long, as the size of the skull was measured one ninth of the total length of the body. In 2006 the park was recognized by the "Guinness Book of World Records" for the largest white crocodile living in captivity also measuring 23 feet. The wetland also hosts a large and diverse population of resident and migratory birds. Rhesus monkey, leopard cat, fishing cat, jungle cat, small Indian civet cat, toddy cat, common mongoose, jackal, striped hyena, Indian fox, wild pig, Indian porcupine, mole rat, long tailed tree mouse, spotted deer, sambar, common otter, smooth Indian otter are also found here.
The Blue Hole is an attraction on the island of Big Pine Key in the Florida Keys. It is an abandoned rock quarry that was used for nearby road fills and Henry Flagler's Overseas Railroad. The water it contains is mostly fresh and is used by various wildlife in the area, such as birds, snakes, alligators, key deer and green iguanas. It is part of the National Key Deer Refuge.
At present, hang baits are illegal off Isla Guadalupe and reputable dive operators do not use them. Operators in South Africa and Australia continue to use hang baits and pinniped decoys. In South Australia, playing rock music recordings underwater, including the AC/DC album "Back in Black" has also been used experimentally to attract sharks.
In Australia (mainly northern; however, box jellyfish can live in subtropical waters as far south as Sydney, with "Carybdea marsupialis" being recorded as far south as Bermagui, Sapphire Coast) the highest risk period for the box jellyfish is between October and May, but stings and specimens have been reported all months of the year. Similarly, the highest risk conditions are those with calm water and a light, onshore breeze; however, stings and specimens have been reported in all conditions.
The Caribbean reef shark occurs throughout the tropical western Atlantic Ocean, from North Carolina in the north to Brazil in the south, including Bermuda, the northern Gulf of Mexico, and the Caribbean Sea. However, it is extremely rare north of the Florida Keys. It prefers shallow waters on or around coral reefs, and is commonly found near the drop-offs at the reefs' outer edges. This shark is most common in water shallower than , but has been known to dive to .
Ocean acidification can also lead to increased sea surface temperature. An increase of about 1 or 2 °C can cause the collapse of the relationship between coral and zooxanthellae, possibly leading to bleaching. Average sea surface temperature in the Great Barrier Reef is predicted to increase between 1 and 3 °C by 2100. This breakdown of the relationship between the coral and the zooxanthellae occurs when Photosystem II is damaged, either due to a reaction with the D1 protein or a lack of carbon dioxide fixation; these result in a lack of photosynthesis and can lead to bleaching.
The Great Barrier Reef Marine Park Authority considers the greatest threat to the Great Barrier Reef to be climate change, causing ocean warming which increases coral bleaching. Mass coral bleaching events due to elevated ocean temperatures occurred in the summers of 1998, 2002 and 2006, and coral bleaching is expected to become an annual occurrence. As global warming continues, corals will not be able to keep up with increasing ocean temperatures. Coral bleaching events lead to increased disease susceptibility, which causes detrimental ecological effects for reef communities.
The Reserve Bank deputy governor Philip Lowe stated in February 2012 that tourism in Australia is having undergo structural changes because of a contraction in the sector due to the impact of a high Australian dollar. By 2012, the estimated value of tourism in the Great Barrier Reef region had reached $5.5 billion. In the wake of Cyclone Marcia, a marketing campaign urged people to visit the region to help it recover. In response to the coral bleaching event of 2016, where only 7% of the reef was unaffected, the tourism industry created a hashtag, #GBRtoday showing healthy corals. Also in 2016, the Australian government asked for a chapter on climate change and the Great Barrier Reef to be removed from UNESCO's report on the status of the Great Barrier Reef over concerns it could impact on tourism. Domestic tourism to the reef subsequently fell.
The Great Barrier Reef: Biology, Environment and Management is a 2007 book by Pat Hutchings, Mike Kingsford and Ove Hoegh-Guldberg. It describes the organisms and ecosystems of Australia's Great Barrier Reef, and the biological, chemical and physical processes that influence them. Issues discussed include climate change, coral bleaching, coral disease and coral reef fishing. The book includes a field guide to help people identify the common animals and plants on the reef. The book has illustrations and contributions from 33 international experts.