Great Barrier Reef
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The Great Barrier Reef is the world's largest
coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...
system, composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the
Coral Sea The Coral Sea () is a marginal sea of the Pacific Ocean, South Pacific off the northeast coast of Australia, and classified as an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion. The Coral Sea extends down t ...
, off the coast of
Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...
,
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
, separated from the coast by a channel wide in places and over deep. The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms. This reef structure is composed of and built by billions of tiny organisms, known as
coral Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...
polyps. It supports a wide diversity of life and was selected as a
World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...
in 1981. CNN labelled it one of the Seven Natural Wonders of the World in 1997. Australian World Heritage places included it in its list in 2007. The Queensland National Trust named it a state icon of Queensland in 2006. A large part of the reef is protected by the
Great Barrier Reef Marine Park The Great Barrier Reef Marine Park protects a large part of Australia's Great Barrier Reef from damaging activities. It is a vast multiple-use Marine Park which supports a wide range of uses, including commercial marine tourism, fishing, ports an ...
, which helps to limit the impact of human use, such as fishing and tourism. Other environmental pressures on the reef and its
ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...
include runoff of humanmade pollutants,
climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
accompanied by mass
coral bleaching Coral bleaching is the process when corals become white due to loss of Symbiosis, symbiotic algae and Photosynthesis, photosynthetic pigments. This loss of pigment can be caused by various stressors, such as changes in water temperature, light, ...
, dumping of dredging sludge and cyclic population outbreaks of the crown-of-thorns starfish. According to a study published in October 2012 by the ''
Proceedings of the National Academy of Sciences ''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Scie ...
'', the reef has lost more than half its coral cover since 1985, a finding reaffirmed by a 2020 study which found over half of the reef's coral cover to have 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 known to and used by the
Aboriginal Australian Aboriginal Australians are the various indigenous peoples of the Australian mainland and many of its islands, excluding the ethnically distinct people of the Torres Strait Islands. Humans first migrated to Australia 50,000 to 65,000 year ...
and
Torres Strait Islander Torres Strait Islanders ( ) are the Indigenous Melanesians, Melanesian people of the Torres Strait Islands, which are part of the state of Queensland, Australia. Ethnically distinct from the Aboriginal Australians, Aboriginal peoples of the res ...
peoples, and is an important part of local groups' cultures and spirituality. The reef is a very popular destination for tourists, especially in the
Whitsunday Islands The Whitsunday Islands are 74 continental islands of various sizes off the central coast of Queensland, Australia, north of Brisbane. The northernmost of the islands are off the coast by the town of Bowen, while the southernmost islands ar ...
and
Cairns Cairns (; ) is a city in the Cairns Region, Queensland, Australia, on the tropical north east coast of Far North Queensland. In the , Cairns had a population of 153,181 people. The city was founded in 1876 and named after William Cairns, Sir W ...
regions. Tourism is an important economic activity for the region, generating over AUD$3 billion per year. In November 2014, Google launched Google Underwater Street View 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 result of warming ocean temperatures. In October 2016, '' Outside'' published an obituary for the reef; the article was criticised for being premature and hindering efforts to bolster the resilience of the reef. In March 2017, the journal ''
Nature Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physic ...
'' published a paper showing that huge sections of an stretch in the northern part of the reef had died in the course of 2016 of high water temperatures, an event that the authors put 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 selection event unfolding". Many of the mature breeding adults died in the bleaching events of 2016–17, leading to low coral birth rates. The types of corals that reproduced also changed, leading to a "long-term reorganisation of the reef ecosystem if the trend continues." The Great Barrier Reef Marine Park Act 1975 (section 54) stipulates an Outlook Report on the Reef's health, pressures, and future every five years. 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 EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, fami ...
weather phenomenon. The Australian Institute of Marine Science conducts annual surveys of the Great Barrier Reef's status, and the 2022 report showed the greatest recovery in 36 years. It is mainly due to the regrowth of two-thirds of the reef by the fast-growing Acropora coral, which is the dominant coral there.


"Discovery" and naming

The Great Barrier Reef has long been known to and used by the
Aboriginal Australian Aboriginal Australians are the various indigenous peoples of the Australian mainland and many of its islands, excluding the ethnically distinct people of the Torres Strait Islands. Humans first migrated to Australia 50,000 to 65,000 year ...
and
Torres Strait Islander Torres Strait Islanders ( ) are the Indigenous Melanesians, Melanesian people of the Torres Strait Islands, which are part of the state of Queensland, Australia. Ethnically distinct from the Aboriginal Australians, Aboriginal peoples of the res ...
peoples, and is an important part of local groups' cultures and spirituality. The first European to sight the Great Barrier Reef was
James Cook Captain (Royal Navy), Captain James Cook (7 November 1728 – 14 February 1779) was a British Royal Navy officer, explorer, and cartographer famous for his three voyages of exploration to the Pacific and Southern Oceans, conducted between 176 ...
in 1770, who sailed and mapped the east coast of Australia. On 11 June 1770, Cook's ship, , ran aground on a shoal south of the present-day location of Cooktown, requiring seven weeks to repair. It was Matthew Flinders who named the Great Barrier Reef, after his more detailed mapping of it in 1802. Flinders used various terms to describe the reefs comprising what we now call the Great Barrier Reef including "great reef", for one such reef, "barrier reef", for any reef preventing a sailing vessel in, or waves from, the open sea, from reaching the coast, and "Barrier Reefs", for the collection of such reefs.


Geology and geography

The Great Barrier Reef is a distinct feature of the East Australian Cordillera division. It reaches from Torres Strait (between Bramble Cay, its northernmost island, and the south coast of
Papua New Guinea Papua New Guinea, officially the Independent State of Papua New Guinea, is an island country in Oceania that comprises the eastern half of the island of New Guinea and offshore islands in Melanesia, a region of the southwestern Pacific Ocean n ...
) in the north to the unnamed passage between
Lady Elliot Island Lady Elliot Island is the southernmost coral cay of the Great Barrier Reef, Australia. The island lies north-east of Bundaberg and covers an area of approximately . It is part of the Capricorn and Bunker Group of islands and is owned by the C ...
(its southernmost island) and Fraser Island in the south. Lady Elliot Island is located southeast of Bramble Cay as the crow flies. It includes the smaller Murray Islands. The
plate tectonic Plate may refer to: Cooking * Plate (dishware), broad, mainly flat vessel commonly used to serve food * Plates, tableware, dishes or dishware used for setting a table, serving food and dining * Plate, the content of such a plate (for example: r ...
theory indicates Australia has moved northwards at a rate of per year, starting during the
Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...
. Eastern Australia experienced a period of
tectonic uplift Tectonic uplift is the orogeny, geologic uplift of Earth#Surface, Earth's surface that is attributed to plate tectonics. While Isostasy, isostatic response is important, an increase in the mean elevation of a region can only occur in response to ...
, which moved the drainage divide in Queensland inland. Also during this time, Queensland experienced volcanic eruptions leading to central and shield
volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...
es and
basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
flows. Some of these became
volcanic island Geologically, a volcanic island is an island of volcanic origin. The term high island can be used to distinguish such islands from low islands, which are formed from sedimentation or the uplifting of coral reefs (which have often formed ...
s. After the
Coral Sea The Coral Sea () is a marginal sea of the Pacific Ocean, South Pacific off the northeast coast of Australia, and classified as an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion. The Coral Sea extends down t ...
Basin formed, coral reefs began to grow in the Basin, but until about 25 million years ago, northern Queensland was still in temperate waters south of the tropicstoo cool to support coral growth. The Great Barrier Reef's development history is complex; after Queensland drifted into tropical waters, it was largely influenced by reef growth and decline as sea level changed. Reefs can increase in diameter by per year, and grow vertically anywhere from per year; however, they grow only above a depth of due to their need for sunlight, and cannot grow above sea level. When Queensland edged into tropical waters 24 million years ago, some coral grew, but a
sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to th ...
regime In politics, a regime (also spelled régime) is a system of government that determines access to public office, and the extent of power held by officials. The two broad categories of regimes are democratic and autocratic. A key similarity acros ...
quickly developed with erosion of the
Great Dividing Range The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills. It runs roughl ...
; creating
river delta A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creat ...
s, oozes and
turbidite A turbidite is the geologic Deposition (geology), deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing ...
s, unsuitable conditions for coral growth. 10 million years ago, the sea level significantly lowered, which further enabled sedimentation. The reef's substrate may have needed to build up from the sediment until its edge was too far away for suspended sediments to inhibit coral growth. In addition, approximately 400,000 years ago there was a particularly warm
Interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...
period with higher sea levels and a water temperature change. The land that formed the substrate of the current Great Barrier Reef was a coastal plain formed from the eroded sediments of the
Great Dividing Range The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills. It runs roughl ...
with some larger hills (most of which were themselves remnants of older reefs or, in rare cases, volcanoes). The Reef Research Centre, a Cooperative Research Centre, has found coral 'skeleton' deposits that date back half a million years. The Great Barrier Reef Marine Park Authority (GBRMPA) considers the earliest evidence of complete reef structures to have been 600,000 years ago. According to the GBRMPA, the current, living reef structure is believed to have begun growing on the older platform about 9,000 years ago. The Australian Institute of Marine Science agrees, placing the beginning of the growth of the current reef at the time of the
Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Last Glacial Coldest Period, was the most recent time during the Last Glacial Period where ice sheets were at their greatest extent between 26,000 and 20,000 years ago. Ice sheets covered m ...
. At around that time, sea level was lower than it is today. From 20,000 years ago until 6,000 years ago, sea level rose steadily around the world. As it rose, the corals could then grow higher on the newly submerged maritime margins of the hills of the coastal plain. By around 13,000 years ago the sea level was only lower than the present day, and corals began to surround the hills of the coastal plain, which were, by then, continental islands. As the sea level rose further still, most of the continental islands were submerged. The corals could then overgrow the submerged hills, to form the present cays and reefs. Sea level here has not risen significantly in the last 6,000 years. The CRC Reef Research Centre estimates the age of the present, living reef structure at 6,000 to 8,000 years old. The shallow water reefs that can be seen in air-photographs and satellite images cover an area of 20,679 km2, most (about 80%) of which has grown on top of limestone platforms that are relics of past (Pleistocene) phases of reef growth. The remains of an ancient barrier reef similar to the Great Barrier Reef can be found in The Kimberley, Western Australia. The Great Barrier Reef World Heritage Area has been divided into 70 bioregions, of which 30 are reef bioregions. In the northern part of the Great Barrier Reef, ribbon reefs and deltaic reefs have formed; these structures are not found in the rest of the reef system. A previously undiscovered reef, 500 metres tall and 1.5 km wide at the base, was found in the northern area in 2020. There are no
atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most ...
s in the system, and reefs attached to the mainland are rare. Fringing reefs are distributed widely, but are most common towards the southern part of the Great Barrier Reef, attached to high islands, for example, the
Whitsunday Islands The Whitsunday Islands are 74 continental islands of various sizes off the central coast of Queensland, Australia, north of Brisbane. The northernmost of the islands are off the coast by the town of Bowen, while the southernmost islands ar ...
. Lagoonal reefs are found in the southern Great Barrier Reef, and further north, off the coast of Princess Charlotte Bay. Crescentic reefs are the most common shape of reef in the middle of the system, for example the reefs surrounding Lizard Island. Crescentic reefs are also found in the far north of the Great Barrier Reef Marine Park, and in the Swain Reefs ( 2022 degrees south). Planar reefs are found in the northern and southern parts, near Cape York Peninsula, Princess Charlotte Bay, and Cairns. Most of the islands on the reef are found on planar reefs. Wonky holes can have localised impact on the reef, providing upwellings of fresh water, sometimes rich in nutrients contributing to
eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...
. Navigation through and around the reefs is a major challenge. More than 20 ships were recorded lost in the region between 1791 and 1850, Surveys between 1815 and 1860 by Phillip Parker King in the Mermaid, Francis Price Blackwood in HMS ''Fly'', Owen Stanley in the ''Rattlesnake,'' and Henry Mangles Denham in the Herald led to considerable navigational improvements, as they outlined the contrasting advantages and perils of the Inner Route (between Australia's east coast and the western edge of the reefs) and the Outer Route, in the open sea.


Ecology

The Great Barrier Reef supports an extraordinary diversity of life, including many vulnerable or
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...
, some of which may be
endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to the reef system. Thirty species of cetaceans have been recorded in the Great Barrier Reef, including the dwarf minke whale, Indo-Pacific humpback dolphin, and the
humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the monotypic taxon, only species in the genus ''Megaptera''. Adults range in length from and weigh u ...
. Large populations of dugongs live there. More than 1,500 fish species live on the reef, including the clownfish, red bass, red-throat emperor, and several species of snapper and coral trout. Forty-nine species mass spawn, while eighty-four other species spawn elsewhere in their range. Seventeen species of
sea snake Sea snakes, or coral reef snakes, are Elapidae, elapid snakes that inhabit Marine (ocean), marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Sea krait, Laticaudinae. Hydrophiinae also includes ...
live on the Great Barrier Reef in warm waters up to deep and are more common in the southern than in the northern section. None found in the Great Barrier Reef World Heritage Area are endemic, nor are any endangered. Six species of
sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback, green, hawksbill, leatherback, loggerh ...
s come to the reef to breed: the green sea turtle, leatherback sea turtle, hawksbill turtle, loggerhead sea turtle, flatback turtle, and the olive ridley. The green sea turtles on the Great Barrier Reef have two genetically distinct populations, one in the northern part of the reef and the other in the southern part. Fifteen species of
seagrass Seagrasses are the only flowering plants which grow in marine (ocean), marine environments. There are about 60 species of fully marine seagrasses which belong to four Family (biology), families (Posidoniaceae, Zosteraceae, Hydrocharitaceae and ...
in beds attract the dugongs and turtles, and provide fish habitat. The most common
genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
of seagrasses are '' Halophila'' and ''
Halodule ''Halodule'' is a genus of plants in the family (biology), family Cymodoceaceae described as a genus in 1841. It is widespread on tropical and semi-tropical ocean shores of all continents except Europe and Antarctica. Species Hybridization has ...
''.
Saltwater crocodile The saltwater crocodile (''Crocodylus porosus'') is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India's east coast across Southeast Asia and the Sundaland to northern Australia and Micronesia. It ha ...
s live in
mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...
and
salt marsh A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. I ...
es on the coast near the reef. Nesting has not been reported, and the salt water crocodile population in the GBRWHA is wide-ranging but low density. Around 125 species of
shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...
, stingray, skates or chimaera live on the reef. Close to 5,000 species of
mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...
have been recorded on the reef, including the giant clam and various
nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs, belonging to the order Nudibranchia, that shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have b ...
s and cone snails. Forty-nine species of pipefish and nine species of
seahorse A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine Osteichthyes, bony fish in the genus ''Hippocampus''. The genus name comes from the Ancient Greek (), itself from () meaning "horse" and () meanin ...
have been recorded. At least seven species of frog inhabit the islands. 215 species of birds (including 22 species of seabirds and 32 species of shorebirds) visit the reef or nest or roost on the islands, including the white-bellied sea eagle and roseate tern. Most nesting sites are on islands in the northern and southern regions of the Great Barrier Reef, with 1.4 to 1.7 million birds using the sites to breed. The islands of the Great Barrier Reef also support 2,195 known plant species; three of these are endemic. The northern islands have 300–350 plant species which tend to be woody, whereas the southern islands have 200 which tend to be herbaceous; the Whitsunday region is the most diverse, supporting 1,141 species. The plants are propagated by birds. There are at least 330 species of ascidians on the reef system with the diameter of . Between 300 and 500 species of bryozoans live on the reef. Four hundred coral species, both hard corals and soft corals inhabit the reef. The majority of these spawn
gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...
s, breeding in mass spawning events that are triggered by the rising sea temperatures of spring and summer, the lunar cycle, and the diurnal cycle. Reefs in the inner Great Barrier Reef spawn during the week after the full moon in October, while the outer reefs spawn in November and December. Its common soft corals belong to 36 genera. Five hundred species of marine algae or seaweed live on the reef, including thirteen species of genus '' Halimeda'', which deposit
calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...
mounds up to wide, creating mini-ecosystems on their surface which have been compared to
rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...
cover.


Environmental threats

Climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
, pollution, crown-of-thorns starfish and fishing are the primary threats to the health of this reef system. Other threats include shipping accidents,
oil spill An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s, 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 The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...
, since 1985, the Great Barrier Reef has lost more than half of its corals with two-thirds of the loss occurring from 1998 due to the factors listed before. In 2022, the northern and central parts of the reef had the highest amount of coral cover since monitoring began, but the cover in the southern part had decreased and bleaching events occurred more frequently.


Climate change

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 Coral bleaching is the process when corals become white due to loss of Symbiosis, symbiotic algae and Photosynthesis, photosynthetic pigments. This loss of pigment can be caused by various stressors, such as changes in water temperature, light, ...
. 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 able 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 The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...
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 work to improve water quality.Great Barrier Reef: Australia must act urgently on water quality, says Unesco
The Guardian. Retrieved 3 June 2017
Climate change has implications for other forms of reef lifesome fish's preferred temperature range leads them to seek new habitat, thus increasing chick mortality in predatory seabirds. Climate change will also affect the sea turtle's population and available habitat. Bleaching events in benthic coral communities (deeper than ) in the Great Barrier reef are not as well documented as those at shallower depths, but recent research has shown that benthic communities are just as negatively impacted in the face of rising ocean temperatures. Five Great Barrier Reef species of large benthic corals were found bleached under elevated temperatures, affirming that benthic corals are vulnerable to thermal stress.


Ocean Acidification

A threat for the Great Barrier Reef is the rising levels of
ocean acidification Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ...
. Ocean acidification occurs when excess atmospheric carbon dioxide gets absorbed into the ocean. This causes a decrease in the pH and this alters the chemistry of the ocean's water. This reduces the amount of aragonite, a key mineral for coral to grow, in the water. The Great Barrier Reef is predicted to lose aragonite at a rate of about 0.1 per decade this century. The acidic water breaks down the materials that coral and shell building creatures need to grow.


Pollution

Another key threat faced by the Great Barrier Reef is
pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...
and declining
water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...
. 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
fertiliser A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrition, plant nutrients. Fertilizers may be distinct from Liming (soil), liming materials or other non- ...
s,
herbicide Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...
s and
pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...
s 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 The Ok Tedi Mine is an Open pit mine, open-pit copper mine, copper and gold mine Mining in Papua New Guinea, in Papua New Guinea located near the headwaters of the Ok Tedi River, in the Star Mountains Rural LLG of the North Fly District of the ...
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.


Loss of coastal wetland

The runoff problem is exacerbated by the loss of coastal
wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
s which act as a natural filter for toxins and help deposit sediment. It is thought that the poor water quality is due to increased light and oxygen
competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indi ...
from
algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...
.


Eutrophication

Farming fertiliser runoff release
nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
,
phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...
, and
potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
into the oceanic ecosystem, and these
limiting nutrient A limiting factor is a variable of a system that causes a noticeable change in output or another measure of a type of system. The limiting factor is in a pyramid shape of organisms going up from the producers to consumers and so on. A factor not l ...
s cause massive algal growth which eventually leads to a reduction in oxygen available for other creatures in a process called
eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...
. 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 hard 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

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

Pesticides used in farming are made 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 effect on the coral.


Pollution from mining

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


Crown of thorns

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 live 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.


Overfishing

The unsustainable
overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...
of keystone species, such as the giant Triton, can disrupt
food chain A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as ...
s 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 Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
from trawling, anchors and nets. As of the middle of 2004, approximately one-third of the
Great Barrier Reef Marine Park The Great Barrier Reef Marine Park protects a large part of Australia's Great Barrier Reef from damaging activities. It is a vast multiple-use Marine Park which supports a wide range of uses, including commercial marine tourism, fishing, ports an ...
is protected from species removal of any kind, including fishing, without written permission.


Shipping

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.''Reef Dreams: Working The Reef'' TV documentary,
Australian Broadcasting Corporation The Australian Broadcasting Corporation (ABC) is Australia’s principal public service broadcaster. It is funded primarily by grants from the federal government and is administered by a government-appointed board of directors. The ABC is ...
, broadcast 6 July 2006
There have been over 1,600 known shipwrecks in the Great Barrier Reef region. On 3 April 2010, the bulk coal carrier ran aground on Douglas Shoals, spilling up to four tonnes of oil into the water and causing extensive damage to the reef.


Shark culling

The government of
Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...
has a "shark control" program ( shark culling) that deliberately kills sharks throughout Queensland, including in the Great Barrier Reef. Environmentalists and scientists say that this program harms the
marine ecosystem Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in Saline water, waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 7 ...
; they also say it is "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 lines in the Great Barrier Reef.Queensland Government Kills Sharks, Faces Court Challenge
. The Maritime Executive. 4 September 2018. Retrieved 30 August 2019. .
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 many other animals (such as
dolphins A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...
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.


Protection and preservation: Reef 2050 plan

In March 2015, the Australian and Queensland's governments formed a plan for the protection and preservation of the reef's universal heritage until 2050. This 35 years plan, titled "Reef 2050 Plan" is a document proposing possible measures for the long-term management of the pollution, climate change and other issues that threaten the life span and value of this global heritage. The plan contains all the elements for measurement and improvements, including; long-term sustainability plan, water quality improvement plan and the investment plan for the protection and preservation of The Reef until 2050. However, whereas the 2050 plan aims to incorporate protective measures such as improving water quality, reef restoration, killing of predatory starfish, it does not incorporate additional measures to address what may be the root cause the problem – climate change, which is caused by greenhouse gas emissions. As such, experts doubted whether it would be enough to save the fragile environment. Another issue is that the time left to the 1.5 °C warming threshold (the temperature limit that coral reefs can still cope with) is very limited. As part of the Reef 2050 plan, an AUD$443 million grant was given to the Great Barrier Reef Foundation in 2018. The announcement of the grant was subject to backlash as the grant had avoided proper tender and transparency processes.


Conservation Policy: Reef 2050 Water Quality Improvement Plan

The Great Barrier Reef contributes to the overall wellbeing of the marine biome. Numerous species of aquatic plants, fish and megafauna use the reef for feeding, shelter and mating. Threats such as
ocean acidification Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ...
, pollution runoff and outbreaks of destructive species like the crown-of-thorns starfish have brought about the decline of this ecosystem. These threats to the reef are not only a danger to the organisms inhabiting it, but also the economy of this region, a large part of which relies on revenue from ecotourism of the Great Barrier Reef. The
Australian government The Australian Government, also known as the Commonwealth Government or simply as the federal government, is the national executive government of Australia, a federal parliamentary constitutional monarchy. The executive consists of the pr ...
has had the goal of protecting this World Heritage Site since 1972 when they created The Australian Institute of Marine Science. The Australian and Queensland governments have contributed about $142.5 million to their National Environmental Science Program which is how they've collected much of their data regarding threats to the Great Barrier Reef. In addition, the Reef 2050 Water Quality Improvement Plan was announced in 2018 in order to help transition local communities, agricultural organizations and industries to more sustainable practices. This plan will join the Queensland government and the Great Barrier Reef Marine Park Authority to manage the amounts of runoff that reach the Great Barrier Reef as well as mitigating crown-of-thorns starfish population flare-ups.


Human use

The Great Barrier Reef has long been known to and used by the
Aboriginal Australian Aboriginal Australians are the various indigenous peoples of the Australian mainland and many of its islands, excluding the ethnically distinct people of the Torres Strait Islands. Humans first migrated to Australia 50,000 to 65,000 year ...
and
Torres Strait Islander Torres Strait Islanders ( ) are the Indigenous Melanesians, Melanesian people of the Torres Strait Islands, which are part of the state of Queensland, Australia. Ethnically distinct from the Aboriginal Australians, Aboriginal peoples of the res ...
peoples. Aboriginal Australians have been living in the area for at least 40,000 years, and Torres Strait Islanders since about 10,000 years ago. For these 70 or so clan groups, the reef is also an important cultural feature. In 1768, Louis de Bougainville encountered the reef, but did not explore it. On 11 June 1770, , captained by explorer
James Cook Captain (Royal Navy), Captain James Cook (7 November 1728 – 14 February 1779) was a British Royal Navy officer, explorer, and cartographer famous for his three voyages of exploration to the Pacific and Southern Oceans, conducted between 176 ...
, ran aground on the Great Barrier Reef, sustaining considerable damage. Lightening the ship and re-floating it during an incoming tide eventually saved it. One of the most famous wrecks was , which sank on 29 August 1791, killing 35 men. The Queensland Museum has led archaeological digs to wreck of ''Pandora'' since 1983. Because the reef had no atolls, it was largely unstudied in the 19th century. During this time, some of the reef's islands were mined for deposits of
guano Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...
, and lighthouses were built as beacons throughout the system. as in
Raine Island Raine Island is a vegetated coral cay in total area situated on the outer edges of the Great Barrier Reef off northeastern Australia. It lies approximately north-northwest of Cairns, Queensland, Cairns in Queensland, about east-northeast of C ...
, the earliest example. In 1922, the Great Barrier Reef Committee began carrying out much of the early research on the reef.


Management

Royal Commissions disallowed oil drilling in the Great Barrier Reef, in 1975 the
Government of Australia The Australian Government, also known as the Commonwealth Government or simply as the federal government, is the national Executive (government), executive government of Australia, a federalism, federal Parliamentary system, parliamentary con ...
created the Great Barrier Reef Marine Park and prohibited various activities. The Great Barrier Reef Marine Park does not include the entire Great Barrier Reef Province. The park is managed, in partnership with the
Government of Queensland The Queensland Government is the state government of Queensland, Australia, a parliamentary constitutional monarchy. Government is formed by the party or coalition that has gained a majority in the state Legislative Assembly, with the governo ...
, through the Great Barrier Reef Marine Park Authority to ensure that it is used in a sustainable manner. A combination of
zoning In urban planning, zoning is a method in which a municipality or other tier of government divides land into land-use "zones", each of which has a set of regulations for new development that differs from other zones. Zones may be defined for ...
, management plans, permits, education and incentives (such as eco-tourism certification) are employed in the effort to conserve the reef. In 1999, the Australian Parliament passed the Environment Protection and Biodiversity Conservation Act, which improved the operation of national environmental law by providing guidance about regional biodiversity conservation priorities. The marine bioregional planning process came from the implementation of this law. This process conserves marine biodiversity by considering the whole ecosystem a species is in and how different species interact in the marine environment. There are two steps to this process. The first step is to identify regional conservation priorities in the five (currently) different marine regions. The second step is to identify marine reserves (protected areas or marine parks) to be added to Australia's National Representative System of Marine Protected Areas. Like protected areas on land, marine reserves are created to protect biodiversity for generations to come. Marine reserves are identified based on criteria written in a document created by Australian and New Zealand Environment and Conservation Council called "Guidelines for establishing the national representative system of marine protected areas", also known as just "the Guidelines". These guidelines are nationally recognised and implemented at the local level based on the Australian policy for implementation outlined in the "Goals and Principles for the Establishment of the National Representative System of Marine Protected Areas in Commonwealth Waters". These policies are in place to make sure that a marine reserve is only added to the NRSMPA after careful evaluation of different data. The priorities for each region are created based on human and environmental threats and the Marine Bioregional Plans are drafted to address these priorities. To assess different region's priorities, three steps are taken, first, a bioregional profile is created, second, a bioregional plan is drafted, and third, the plan is finalised. After the plan is finalised, activity in different bioregions may become limited based on particular threats an activity may pose. In 2001, the GBRMPA released a report about the declining water quality in the Great Barrier Reef and detailed the importance of this issue. In response to this report, in 2003, the Australian and Queensland governments launched a joint initiative to improve the quality of water entering the Great Barrier Reef. The decline in the quality of water over the past 150 years (due to development) has contributed to coral bleaching, algal blooms, and pesticide pollution. These forms of pollution have made the reef less resilient to climate change. When the plan was introduced in October 2003, it originally contained 65 actions built on previous legislation. Their immediate goal was to halt and reverse the decline in water quality entering the reef by 2013. By 2020, they hope that the quality of the water entering in the reef improves enough so that it doesn't have a detrimental impact on the health of the Great Barrier Reef. To achieve these goals they decided to reduce pollutants in the water entering the reef and to rehabilitate and conserve areas of the reef that naturally help reduce water pollutants. To achieve the objectives described above, this plan focuses on non-point sources of pollution, which cannot be traced to a single source such as a waste outlet. The plan specifically targets nutrients, pesticides and sediment that make their way into the reef as a result of agricultural activities. Other non-point sources of pollution that are attributed to urban areas are covered under different legislation. In 2009, the plan was updated. The updated version states that to date, none of the efforts undertaken to improve the quality of water entering the reef has been successful. The new plan attempts to address this issue by "targeting priority outcomes, integrating industry and community initiatives and incorporating new policy and regulatory frameworks (Reef Plan 5)". This updated version has improved the clarity of the previous plan and targets set by that plan, have improved accountability and further improved monitoring and assessment. The 2009 report found that 41 out of the 65 actions met their original goals, however, 18 were not progressing well according to evaluation criteria as well as 6 were rated as having unsatisfactory levels of progress. Some key achievements made since the plan's initial passing in 2003 were the establishment of the Reef Quality Partnership to set targets, report findings and monitor progress towards targets, improved land condition by landowners was rewarded with extended leases, Water Quality Improvement Plans were created to identify regional targets and identified management changes that needed to be made to reach those targets, Nutrient Management Zones have been created to combat
sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...
loss in particular areas, education programs have been started to help gather support for sustainable agriculture, changes to land management practices have taken place through the implementation of the Farm Management Systems and codes of practice, the creation of the Queensland Wetland program and other achievements were made to help improve the water quality flowing into the coral reefs. A taskforce of scientists was also created to assess the impact of different parts of the plan on the quality of water flowing into the coral reefs. They found that many of the goals have yet to be reached but found more evidence that states that improving the water quality of the Great Barrier Reef will improve its resilience to climate change. The Reefocus summit in 2008, which is also detailed in the report, came to similar conclusions. After this, a stakeholder working group was formed that worked between several groups as well as the Australian and Queensland governments to update reef goals and objectives. The updated version of the plan focuses on strategic priority areas and actions to achieve 2013 goals. Also quantitative targets have been made to critically assess whether targets are being met. Some examples of the water quality goals outlined by this plan are that by 2013, there will be a 50% reduction in nitrogen and phosphorus loads at the end of catchments and that by 2020, there will be a reduction in sediment load by 20%. The plan also outlines a number of steps that must be taken by landholders to help improve grazing, soil, nutrient, and chemical management practices. There are also a number of supporting initiatives to take place outlined in the plan to help create a framework to improve land use practices which will in turn improve water quality. Through these means the governments of Australia and Queensland hope to improve water quality by 2013. The 2013 outlook report and revised water quality plan will assess what needs to be done in the future to improve water quality and the livelihoods of the wildlife that resides there. In July 2004, a new zoning plan took effect for the entire Marine Park, and has been widely acclaimed as a new global benchmark for
marine ecosystem Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in Saline water, waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 7 ...
conservation. The rezoning was based on the application of systematic conservation planning techniques, using marxan software. While protection across the Marine Park was improved, the highly protected zones increased from 4.5% to over 33.3%. At the time, it was the largest Marine Protected Area in the world, although in 2006, the new Northwestern Hawaiian Islands National Monument became the largest. In 2006, a review of the Great Barrier Reef Marine Park Act of 1975 recommended that there should be no further zoning plan changes until 2013, and that every five years, a
peer-reviewed Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work ( peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review ...
outlook report should be published, examining the reef's health, management, and environmental pressures. In each outlook report, several assessments are required. Each assessment has a set of assessment criteria that allows for better presentation of available evidence. Each assessment is judged by these criteria and given a grade. Every outlook report follows the same judging and grading process so that information can be tracked over time. No new research is done to produce the report. Only readily available information goes into the report so little of what is known about the Reef is actually featured in each outlook report.


Abbot Point coal port dredge dumping controversy

In December 2013, Greg Hunt, the Australian environment minister, approved a plan for dredging to create three shipping terminals as part of the construction of a coalport. According to corresponding approval documents, the process will create around 3 million cubic metres of dredged seabed that will be dumped within the Great Barrier Reef marine park area. On 31 January 2014, the GBRMPA issued a dumping permit that will allow three million cubic metres of sea bed from Abbot Point, north of Bowen, to be transported and unloaded in the waters of the Great Barrier Reef Marine Park. Potential significant harms have been identified in relation to dredge spoil and the process of churning up the sea floor in the area and exposing it to air: firstly, new research shows the finer particles of dredge spoil can cloud the water and block sunlight, thereby starving sea grass and coral up to distances of 80 km away from the point of origin due to the actions of wind and currents. Furthermore, dredge spoil can literally smother reef or sea grass to death, while storms can repeatedly resuspend these particles so that the harm caused is ongoing; secondly, disturbed sea floor can release toxic substances into the surrounding environment. The dredge spoil from the Abbot Point port project is to be dumped away, near Bowen in north Queensland, and the approval from the Authority will result in the production of an extra 70 million tonnes of coal annually, worth between A$1.4 billion and $2.8 billion. Authority chairman, Dr Russell Reichelt, stated after the confirmation of the approval:
This approval is in line with the agency's view that port development along the Great Barrier Reef coastline should be limited to existing ports. As a deepwater port that has been in operation for nearly 30 years, Abbot Point is better placed than other ports along the Great Barrier Reef coastline to undertake expansion as the capital and maintenance dredging required will be significantly less than what would be required in other areas. It's important to note the seafloor of the approved disposal area consists of sand, silt and clay and does not contain coral reefs or seagrass beds.
The approval was provided with a corresponding set of 47 new environmental conditions that include the following: * A long-term water quality monitoring plan extending five years after the disposal activity is completed. * A heritage management plan to protect the Catalina second world war aircraft wreck in Abbot Bay. * The establishment of an independent dredging and disposal technical advice panel and a management response group, to include community representatives. The Australian Federal Government announced on 13 November that there would now be a ban on the dumping of dredge spoil in the Great Barrier Reef Marine Park. The World Heritage Committee asked Environment Minister Greg Hunt to investigate alternative options to dump on land instead. The Queensland government and the Commonwealth have now accepted the alternative option and advice from The World Heritage Committee and will now commence dumping on land.


Tourism

Due to its vast
biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...
, warm clear waters and accessibility from the tourist boats called " live aboards", the reef is a very popular destination, especially for scuba divers. Tourism on the Great Barrier Reef is concentrated in Cairns and also The Whitsundays due to their accessibility. These areas make up 7–8% of the park's area. The Whitsundays and
Cairns Cairns (; ) is a city in the Cairns Region, Queensland, Australia, on the tropical north east coast of Far North Queensland. In the , Cairns had a population of 153,181 people. The city was founded in 1876 and named after William Cairns, Sir W ...
have their own Plans of Management. Many cities along the Queensland coast offer daily boat trips. Several continental and coral cay islands are now
resort A resort (North American English) is a self-contained commercial establishment that aims to provide most of a vacationer's needs. This includes food, drink, swimming, accommodation, sports, entertainment and shopping, on the premises. A hotel ...
s, including Green Island and
Lady Elliot Island Lady Elliot Island is the southernmost coral cay of the Great Barrier Reef, Australia. The island lies north-east of Bundaberg and covers an area of approximately . It is part of the Capricorn and Bunker Group of islands and is owned by the C ...
. As of 1996, 27 islands on the Great Barrier Reef supported resorts. In 1996, most of the tourism in the region was domestically generated and the most popular visiting times were during the Australian winter. At this time, it was estimated that tourists to the Great Barrier Reef contributed A$776 million per annum. As the largest commercial activity in the region, it was estimated in 2003 that tourism generated over A$4 billion annually, and the 2005 estimate increased to A$5.1 billion. A Deloitte report published by the Great Barrier Reef Marine Park Authority in March 2013 states that the Reef's 2,000 kilometres of coastline attracts tourism worth A$6.4 billion annually and employs more than 64,000 people. Approximately two million people visit the Great Barrier Reef each year. Although most of these visits are managed in partnership with the marine Tourism industry, there is a concern among the general public that tourism is harmful to the Great Barrier Reef. A variety of boat tours and cruises are offered, from single day trips, to longer voyages. Boat sizes range from
dinghies A dinghy is a type of small boat, often carried or Towing, towed by a Watercraft, larger vessel for use as a Ship's tender, tender. Utility dinghies are usually rowboats or have an outboard motor. Some are rigged for sailing but they diffe ...
to superyachts. Glass-bottomed boats and underwater
observatories An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysics, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Th ...
are also popular, as are
helicopter A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...
flights. By far, the most popular tourist activities on the Great Barrier Reef are snorkelling and diving, for which pontoons are often used, and the area is often enclosed by nets. The outer part of the Great Barrier Reef is favoured for such activities, due to water quality. Management of tourism in the Great Barrier Reef is geared towards making tourism ecologically sustainable. A daily fee is levied that goes towards research of the Great Barrier Reef. This fee ends up being 20% of the GBRMPA's income. Policies on
cruise ship Cruise ships are large passenger ships used mainly for vacationing. Unlike ocean liners, which are used for transport, cruise ships typically embark on round-trip voyages to various ports of call, where passengers may go on Tourism, tours k ...
s, bareboat charters, and anchorages limit the traffic on the Great Barrier Reef. The problems that surround ecotourism in the Great Barrier Reef revolve around permanent tourism platforms. Platforms are large, ship-like vessels that act as a base for tourists while scuba diving and snorkelling in the Great Barrier Reef. Seabirds will land on the platforms and defecate which will eventually be washed into the sea. The feces carry nitrogen, phosphorus and often DDT and mercury, which cause aspergillosis, yellow-band disease, and black band disease. Areas without tourism platforms have 14 out of 9,468 (1.1%) diseased corals versus areas with tourism platforms that have 172 out of 7,043 (12%) diseased corals. Tourism is a major economic activity for the region. Thus, while non-permanent platforms could be possible in some areas, overall, permanent platforms are likely a necessity. Solutions have been suggested to siphon bird waste into gutters connecting to tanks helping lower runoff that causes coral disease. The Great Barrier Reef Marine Park Authority has also placed many permanent anchorage points around the general use areas. These act to reduce damage to the reef due to anchoring destroying soft coral, chipping hard coral, and disturbing sediment as it is dragged across the bottom. Tourism operators also must comply with speed limits when traveling to or from tourist destinations, to prevent excessive wake from the boats disturbing the reef ecosystem.


Fishing

The
fishing industry The fishing industry includes any industry or activity that takes, cultures, processes, preserves, stores, transports, markets or sells fish or fish products. It is defined by the Food and Agriculture Organization as including recreational, sub ...
in the Great Barrier Reef, controlled by the Queensland Government, is worth A$1 billion annually. It employs approximately 2000 people, and fishing in the Great Barrier Reef is pursued commercially, for recreation, and as a traditional means for feeding one's family.


Dugong hunting

Under the Native Title Act 1993, native title holders retain the right to legally hunt dugongs and green turtles for "personal, domestic or non-commercial communal needs". Four traditional owners groups agreed to cease the hunting of dugongs in the area in 2011 due to their declining numbers, partially accelerated by seagrass damage from Cyclone Yasi.


See also

* Catlin Seaview Survey * Coral Triangle *
Galápagos Islands The Galápagos Islands () are an archipelago of volcanic islands in the Eastern Pacific, located around the equator, west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with a population of sli ...
* Great Barrier Reef Committee (1922–1982) * Great Southern Reef * Islands on the Great Barrier Reef * Komodo National Park * List of reefs * Ocean acidification in the Great Barrier Reef * Sixth extinction * Valdes Peninsula


References


Further reading

* * * * * * *


External links

*
World heritage listing for Great Barrier Reef

Great Barrier Reef
UNESCO Collection on Google Arts and Culture
Great Barrier Reef Marine Park Authority

CRC Reef Research Centre
*

Four CornersABC.au
Great Barrier Reef scientists confirm largest die-off of corals recorded
''
The Guardian ''The Guardian'' is a British daily newspaper. It was founded in Manchester in 1821 as ''The Manchester Guardian'' and changed its name in 1959, followed by a move to London. Along with its sister paper, ''The Guardian Weekly'', ''The Guardi ...
.'' 28 November 2016.
Great Barrier Reef Foundation
web archive,
State Library of Queensland State Library of Queensland (State Library) is the state public reference and research library of Queensland, Australia, operated by the Government of Queensland, state government. The Library is governed by the Library Board of Queensland, whi ...

Great Barrier Reef Expedition Photographs 1928-1929
State Library of Queensland
Memories and Mutton Birds Women of the Great Barrier Reef
John Oxley Library blog
2020 John Oxley Library Fellows- Research Reveals: Women of the Great Barrier Reef
State Library of Queensland
2020 John Oxley Library Fellows: Deb Anderson and Kerrie Foxwell-Norton. The Terry Ridgway Story
State Library of Queensland {{Authority control Landforms of the Coral Sea Reefs of Australia Marine ecoregions World Heritage Sites in Australia Underwater diving sites in Australia Tourist attractions in Queensland Physiographic provinces Australian National Heritage List Central Indo-Pacific