Great Barrier Reef

The Great Barrier Reef is a world's largest Coral Sea, off the coast of seven natural wonders of a world in 1997. Australian World Heritage places mentioned it in its list in 2007. The Queensland National Trust named it a state icon of Queensland in 2006.

A large component of the reef is protected by the Great Barrier Reef Marine Park, which gives to limit the affect of human use, such(a) as fishing and tourism. Other environmental pressures on the reef & its ecosystem increase runoff, climate change accompanied by mass coral bleaching, dumping of dredging sludge and cyclic population outbreaks of the crown-of-thorns starfish. According to a discussing published in October 2012 by the Proceedings of the National Academy of Sciences, the reef has lost more than half its coral go forward since 1985, a finding reaffirmed by a 2020 inspect which found over half of the reef's coral carry on to pretend been lost between 1995 and 2017, with the effects of a widespread 2020 bleaching event not yet quantified.

The Great Barrier Reef has long been call to and used by the Google Underwater Street belief in 3D of the Great Barrier Reef.

A March 2016 report stated that coral bleaching was more widespread than previously thought, seriously affecting the northern parts of the reef as a statement of warming ocean temperatures. In October 2016, Outside published an obituary for the reef; the article was criticized for being premature and hindering efforts to bolster the resilience of the reef. In March 2017, the journal Nature published a paper showing that huge sections of an 800-kilometre 500 mi stretch in the northern element of the reef had died in the course of 2016 due to high water temperatures, an event that the authors increase down to the effects of global climate change. The percentage of baby corals being born on the Great Barrier Reef dropped drastically in 2018 and scientists are describing it as the early stage of a "huge natural option event unfolding". many of the mature breeding adults died in the bleaching events of 2016–17 leading to low coral birth rates. The category of corals that reproduced also changed, main to a "long-term reorganisation of the reef ecosystem if the trend continues."

The Great Barrier Reef Marine Park Act 1975 item 54 demands every five years an Outlook description on the Reef's health, pressures, and future. The last report was published in 2019. In March 2022, another mass bleaching event has been confirmed, which raised further concerns about the future of this reef system, especially when considering the possible effects of El Niño weather phenomenon.

Environmental threats

Climate change, pollution, crown-of-thorns starfish and fishing are the primary threats to the health of this reef system. Other threats include shipping accidents, oil spills, and tropical cyclones. Skeletal Eroding Band, a disease of bony corals caused by the protozoan Halofolliculina corallasia, affects 31 coral species. According to a 2012 study by the National Academy of Sciences, since 1985, the Great Barrier Reef has lost more than half of its corals with two-thirds of the harm occurring from 1998 due to the factors listed before.

The Great Barrier Reef Marine Park command 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 marine heatwaves occurred in the summers of 1998, 2002, 2006, 2016, 2017 and 2020, and coral bleaching is expected to become an annual occurrence. In 2020, a study found that the Great Barrier Reef has lost more than half of its corals since 1995 due to warmer seas driven by climate change. As global warming continues, corals will not be professionals such(a) as lawyers and surveyors to keep up with increasing ocean temperatures. Coral bleaching events lead to increased disease susceptibility, which causes detrimental ecological effects for reef communities.

In July 2017 UNESCO published in a draft decision, expressing serious concern about the impact of coral bleaching on the Great Barrier Reef. The draft decision also warned Australia that it will not meet the targets of the Reef 2050 report without considerable score to news that updates your information water quality.

Climate change has implications for other forms of reef life—some fish's preferred temperature range leads them to seek new habitat, thus increasing chick mortality in predatory seabirds. Climate conform will also affect the sea turtle's population and usable habitat.

Bleaching events in benthic coral communities deeper than 20 metres or 66 feet in the Great Barrier reef are not as well documented as those at shallower depths, but recent research has submission that benthic communities are just as negatively impacted in the face of rising ocean temperatures. Five Great Barrier Reef kind of large benthic corals were found bleached under elevated temperatures, affirming that benthic corals are vulnerable to thermal stress.

Another key threat faced by the Great Barrier Reef is pollution and declining water quality. The rivers of north-eastern Australia pollute the Reef during tropical flood events. Over 90% of this pollution comes from farm runoff. 80% of the land adjacent to the Great Barrier Reef is used for farming including intensive cropping of sugar cane, and major beef cattle grazing. Farming practices damage the reef due to overgrazing, increased run-off of agricultural sediments, nutrients and chemicals including fertilisers, herbicides and pesticides representing a major health risk for the coral and biodiversity of the reefs.

According to a 2016 report, while higher regulation contributes to less overall pollution from "other land uses, such as industrial, mining, port development, dredging and urban development", these can still be locally significant. Sediments containing high levels of copper and other heavy metals sourced from the Ok Tedi Mine in Papua New Guinea are a potential pollution risk for the far northern Great Barrier Reef and Torres Strait regions.

Some 67% of corals died in the reef's worst-hit northern section, the ARC Centre of Excellence for Coral Reef Studies report said.

The runoff problem is exacerbated by the loss of coastal wetlands which act as a natural filter for toxins and assist deposit sediment. it is for thought that the poor water quality is due to increased light and oxygen competition from algae.

Farming fertiliser runoff release nitrogen, phosphorus, and potassium into the oceanic ecosystem, and these limiting nutrients cause massive algal growth which eventually leads to a reduction in oxygen usable for other creatures in a process called eutrophication. This decreases the biodiversity in the affected areas, altering the species composition. A study by Katharina Fabricius and Glen Death of Australian Institute of Marine Science found that tough corals numbers were almost double on reefs that were far from agricultural areas.

Fertilizers also increase the amount of phytoplankton available for the crown-of-thorns starfish larvae to consume. A study showed that a doubling of the chlorophyll in the water leads to a tenfold increase in the crown-of-thorns starfish larvae's survival rate.

Sediment runoff from farming carries chemicals into the reef environment also reduces the amount of light available to the corals decreasing their ability to extract energy from their environment.

Pesticides used in farming are offered up of heavy metals such as lead, mercury, arsenic and other toxins are released into the wider environment due to erosion of farm soil, which has a detrimental issue on the coral.

Mining company Queensland Nickel discharged nitrate-laden water into the Great Barrier Reef in 2009 and 2011 – on the later occasion releasing 516 tonnes 508 long tons; 569 short tons of waste water. The Great Barrier Reef Marine Park Authority GBRMPA stated "We have strongly encouraged the organization to investigate options that do not entail releasing the material to the environment and to establish a management plan to eliminate this potential hazard; however, GBRMPA does not have legislative control over how the Yabulu tailings dam is managed".

The crown-of-thorns starfish preys on coral polyps. Large outbreaks of these starfish can devastate reefs. In 2000, an outbreak contributed to a loss of 66% of symbolize coral cover on sampled reefs in a study by the Reef Research Centre RRC. Outbreaks are believed to occur in natural cycles, worsened by poor water quality and overfishing of the starfish's predators.

The unsustainable overfishing of keystone species, such as the giant Triton, can disrupt food chains vital to reef life. Fishing also impacts the reef through increased water pollution from boats, by-catch of unwanted species such as dolphins and turtles and habitat destruction from trawling, anchors and nets. As of the middle of 2004, approximately one-third of the Great Barrier Reef Marine Park is protected from species removal of all kind, including fishing, without a thing that is said permission.

Shipping accidents are a pressing concern, as several commercial shipping routes pass through the Great Barrier Reef. Although the route through the Great Barrier Reef is not easy, reef pilots consider it safer than outside the reef in the event of mechanical failure, since a ship can sit safely while being repaired. There have been over 1,600 known shipwrecks in the Great Barrier Reef region. On 3 April 2010, the ran aground on Douglas Shoals, spilling up to four tonnes of oil into the water and causing extensive damage to the reef.

The government of Queensland has a "shark control" script shark culling that deliberately kills sharks throughout Queensland, including in the Great Barrier Reef. Environmentalists and scientists say that this script harms the marine ecosystem; they also say it is for "outdated, cruel and ineffective". The Queensland "shark control" program uses shark nets and drum lines with baited hooks to kill sharks in the Great Barrier Reef – there are 173 lethal drum cut in the Great Barrier Reef. In Queensland, sharks found alive on the baited hooks are shot. Queensland's "shark control" program killed about 50,000 sharks from 1962 to 2018. Also, Queensland's "shark control" program has also killed numerous other animals such as dolphins and turtles — the program killed 84,000 marine animals from 1962 to 2015, including in the Great Barrier Reef. In 2018, Humane Society International filed a lawsuit against the government of Queensland to stop shark culling in the Great Barrier Reef.