The Great Barrier Reef

The Great Barrier Reef can be seen from space and is the world’s largest unique structure built by living organisms. This reef structure is made up and built by billions of tiny organisms, called coral polyps. It supports a great variety of life and was selected as a World Heritage Site in 1981.CNN referred to it as one of the seven natural wonders of the world in 1997. It was nominated by the Australian World Heritage Places in 2007. The Queensland National Trust named it an icon of Queensland in 2006. Australia’s World Heritage sites inscribed it on the list in 2007.

The Queensland National Trust made it an icon for Queensland in 2006. Much of the reef is protected by the Great Barrier Reef Marine Park, which helps to limit the impact of human use, such as fisheries and tourism. The Great Barrier Reef has long been known and used by the indigenous peoples of Australia and the Torres Strait Islanders. The reef is a very popular destination for tourists, particularly in the Whitsunday Islands and Cairns areas. Tourism is a significant economic activity for the region, generating over AUD$3 billion annually.

Where is the Great Barrier Reef?

The Great Barrier Reef is the most extensive network of coral reefs in the world composed of over 2,900 individual reefs. It has spread on 900 islands for over 2,300 kilometers (1,400 mi) over an area of approximately 344,400 square kilometers (133,000 sq mi). The reef lies in the Coral Sea off the coast of Queensland, Australia.

The Great Barrier Reef is a distinct characteristic of the division of the Cordillera of Eastern Australia. 

Coral Bleaching

Other environmental pressures on the reef and its ecosystem include runoff, climate change with massive coral bleaching, dredging spill sludge, and cyclic population outbreaks of the crown-of-thorns starfish. A study published in October 2012 by the Proceedings of the National Academy of Sciences found that the reef has lost more than half of its coral cover since 1985, A study was done by 2020 also found that 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.

A report published in March 2016 indicated that coral bleaching was more common than previously thought, seriously affecting the northern parts of the reef.

Coral bleaching

Why is the Great Barrier Reef is so special?

The Great Barrier Reef contains an extraordinary diversity of life, including many vulnerable and threatened species, some of which may be endemic to the reef system. Thirty species of cetaceans have been identified in the Great Barrier Reef, including the minke whale, the Indo-Pacific humpback whale, and the humpback whale. It is home to large dugongs. More than 1,500 species of fish live on the reef, including clownfish, red bass, the tail of the red-throat emperor, and several species of snapper and coral trout. Forty-nine species are mass spawners, and eighty-four other species are spawners elsewhere in their range. Seventeen species of marine snakes live on the Great Barrier Reef in warm waters up to 50 m (160 ft) deep and are more common in the south than in the northern section.

None found within the Great Barrier Reef World Heritage Area is endemic, and none is threatened. Six species of sea turtles breed on the reef: the green sea turtle, the leatherback turtle, the sparrow turtle, the loggerhead turtle, the flat-backed turtle, and the olive ridley. Green marine turtles on the Great Barrier Reef have two genetically distinct populations, one in the northern portion of the reef and the other in the southern part. Fifteen species of seagrasses in the beds attract dugongs and tortoises and provide fish habitat. 

Saltwater crocodiles live in mangroves and salt marshes on the coast close to the reef. Breeding has not been reported, and GBRWHA has a large but sparsely populated population of saltwater crocodiles. More than 125 species of sharks, rays, rays, or chimeras live on the reef. Nearly 5,000 species of mollusks have been recorded on the reef, including giant clams and various nudibranchs, and conical snails. Forty-nine rockfish species and nine seahorse species have been documented. They are home to at least seven species of frogs. 215 bird species (of which 22 seabird species and 32 shorebird species) visit the reef or nest or perch on the islands, including the white-bellied sea eagle and roseate tern.

Plants in the Great Barrier Reef

Most breeding sites are on islands in the northern and southern regions of the Great Barrier Reef. The Great Barrier Reef Islands are also home to 2195 known plant species, three of which are endemic. The northern islands have between 300 and 350 plant species that tend to be woody, while the southern islands have 200 which tend to be herbaceous the Whitsunday region is the most diverse, supporting 1,141 species. Plants are distributed by birds.

There are at least 330 species of ascidian in the reef system, each 1-10 cm (0.4-4 in.) in diameter. Between 300 and 500 species of bryozoans are found on the reef. The majority of these gametes spawn, reproducing in the mass spawning events which are triggered by the rising sea temperatures of spring and summer, the lunar cycle, and the diurnal cycle. The reefs of the Inner Great Barrier spawn during the week after the October full moon, while the reefs spawn in November and December.

Sea Animal near Coral Reefs

Is the Great Barrier Reef in Danger?

Climate change, pollution, the star of the sea crown of thorns, and fishing are the major threats to the health of this reef system. Other threats include marine incidents, oil spills, and tropical cyclones. According to a study conducted in 2012 by the National Academy of Sciences, since 1985, the Great Barrier Reef has lost more than half of its corals.  The Great Barrier Reef Marine Park Authority believes that the greatest threat to the Great Barrier Reef is climate change, which causes ocean warming. It increases coral bleaching. Massive incidents of coral bleaching due to marine heatwaves occurred during the summers of 1998, 2002, 2006, 2016, 2017, and 2020, and coral bleaching is expected to become an annual occurrence.

Poor Water Quality and the Great Barrier Reef.

Poor water quality is also a major pollutant of the Great Barrier Reef.  The rivers of North-Eastern Australia pollute the reef during tropical floods. More than 90% of this pollution is caused by farm runoff. 80% of the land next to the Great Barrier Reef has been used for farming including intensive cropping of sugarcane, and major beef cattle grazing. Farming practices damage the reef due to overgrazing, increased runoff of agricultural sediments, nutrients, and chemicals, including fertilizers herbicides, and pesticides representing a major health risk for the coral and biodiversity of the reefs.

Sediments containing elevated levels of copper and other heavy metals from the Ok Tedi mine in Papua New Guinea present a potential risk of pollution. According to the ARC Centre of Excellence for Coral Reef Studies, 67% of the corals died in the northern part of the reef most affected. The runoff problem is exacerbated by the loss of coastal wetlands that provide a natural filter for toxins and contribute to sediment deposition. Poor water quality is thought to be a result of increased competition from light and oxygen from algae.

Farm fertilizer runoff releases nitrogen, phosphorus, and potassium to the ocean ecosystem, and these limiting nutrients cause abundant algae growth which eventually leads to a reduction in oxygen available for other creatures in a process called eutrophication. This reduces biodiversity in affected areas, changing species composition. Fertilizers also increase the amount of phytoplankton that starfish larvae from the thorn wreath can consume. Unsustainable overfishing of key species, such as the giant Triton, can disrupt life-sustaining food chains.

The Great barrier reefs

How Fishing affects the Great coral Reef?

Fishing also impacts the reef due to increased water pollution from boats, by-catch of unwanted species (such as dolphins and turtles), and habitat destruction from trawling, anchors, and nets. By the middle of 2004, approximately one-third of the Great Barrier Reef Marine Park was protected from the removal of any species, including fishing, without written permission. Because of its large biodiversity, warm and clear waters, and the accessibility of tourist boats called “LiveAboards”, the reef is a very popular destination.

Tourism on the Great Barrier Reef is concentrated in Cairns and also in the Whitsundays because of its accessibility. These areas comprise between 7% and 8% of the parking area. The problems surrounding eco-tourism on the Great Barrier Reef revolve around permanent tourism platforms. The problems surrounding eco-tourism on the Great Barrier Reef revolve around permanent tourism platforms. Seabirds will land on the rigs and defecate, which will eventually be discarded into the sea.

Animals with Corals

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