Environmental Threats
The Great Barrier Reef sustains the life of a large number of animals. That is why the government and the Great Barrier Reef Marine Park Authority ensure that the reef is safeguarded against activities or animals that threaten it. Given its importance to the number of animals living on the Great Barrier Reef, the government and the Marine Park Authority try their best to sustain and protect the reef. List of environmental threats to the coral reefs include the crown-of-thorns starfish, tourists, over fishing, oil spills, shipwrecks, the degradation of water quality, coral bleaching and the increase of global warming.
Crown-of-thorns starfish
Among the list of threats to the coral reefs, the Crown-of-thorns starfish is probably the most hazardous. This starfish is a predator that eats coral polyps by releasing digestive enzymes that absorb the coral's liquefied tissue. It was estimated that an adult crown-of-thorns-starfish can destroy up to 6mē of coral reef in a year.
Crown-of-thorns- outbreak go through a series of stages that can take up to 25 years. An outbreak of crown-of-thorns starfish happens when more than 30 adult starfishes are present in an area of one hectare. Although attacks of this type of starfish only occur in natural cycles, human activities in the Barrier Reef can aggravate the effects. Water quality reduction caused by agriculture can cause the starfish larvae to thrive. In addition, the over fishing of the Giant Triton, the starfish's natural predator, also contribute to the abundance of crown-of-thorns starfish.
Coral Bleaching
Corals are sensitive to intense heat. That is the reason why the increase in water temperature caused by the El Nino effect and pollution can be devastating for coral reefs. When the temperature exceeds the normal temperature range of corals, the algae dies. Loss of algae, which gives corals their color, can leave the coral tissue bleached or colorless. Coral bleaching will eventually result to the death of numerous coral reefs.
Tourists
Another possible threat to the coral reefs is the tourists themselves. Reef walking, dropping anchors and pollution can damage the fragile corals reefs. In addition, suntan lotions and perspiration may also cause a negative effect on the reef environment.
Over fishing
Other than tourism, the fishing industry is also one of the most lucrative industries in the Great Barrier Reef. It gains a profit of AU$1 billion yearly. Fishing in the Barrier Reef is not only pursued for its commercial use, but also for recreation. However, most areas of the reef are protected by the Marine Park Authority. As such, fishing is not allowed in some parts of the region and catching animals like dolphins, green turtles, whales and dugongs are prohibited.
Fishing in the Great Barrier Reef becomes a threat to the ecosystem if people catch rare animals or important species like the Giant Triton that can disrupt the food chain and natural order of life. Fishing also because a negative effect through added pollution caused by boats, trawling, nets and anchors that causes the destruction of coral reef habitat. At the middle of 2004, approximately one-third of the Great Barrier Reef Marine Park is protected from fishing and transfer of any type of species without a written permission.
Oil spills
In the 1960s up to the 1970s, there was a growing speculation that the Great Barrier Reef is the entry point to a vast oil deposit and gas. That is the reason why in 1970, two Royal Commissions were assigned to explore and drill the Great Barrier Reef area for possible petroleum and oil. Today, oil drilling is banned on the Great Barrier Reef, though oil spills, that kill coral reefs, often occur within the area. A total of 282 oil spills happened in the Great Barrier Reef between 1987-2002.
Shipping accidents
Shipping accidents are also threats to the survival of the Great Barrier Reef, as several commercial shipping routes pass through the reef system. In addition, 20 groundings and 11 collisions were reported on the shipping route of the Great Barrier Reef from 1985-2001.
In addition to the shipwrecks, boats can destroy the reef when they throw wastes and other foreign objects in the water. Plus, ships release a toxic to the seawater that endangers both humans and marine organisms called the Tributyltin or TBT compounds -- used as an anti-fouling paint on ship hulls.
Water Quality and Temperature
Since Australia is located below the equator, it is ruled by a tropical temperature, the type that paves the way for the growth of coral reefs. Unfortunately, the increase in human population in Australia posed a great environmental risk to the survival of the world's most extensive ecosystem of coral reefs -- the Great Barrier.
Human wastes and the chemicals from the industrial sites from the nearby cities such as Townsville and the Cairns are affecting the quality of water flowing through the Great Barrier Reef. Out of the 3,000 coral reefs, approximately 400 are in danger of becoming contaminated because the quality of water within the venue is degrading because of the chemical and agricultural wastes such as copper, and the lack of wetlands, which serve as nature's water filters. Moreover, other theories on why seawater quality has been degrading are the increasing number of algae that pose competition in oxygen and light with the coral reefs.
Another threat to the Great Barrier Reef is the rising temperatures of the ocean. The thinning of the ozone layer due to excess burning of fossil fuels and other human activities has greatly affected the water temperatures through global warming. Because of prolonged warm temperatures, corals release their coloring agents, retaining only their white skeletons made of calcium carbonate. This event is called coral bleaching and it has increased within the past years because of the El Nino effect and continuous increase in global temperature. Because of the environmental threats, the Great Barrier Reef Marine Park Authority is not only compelled to promote tourism, but also the preservation of the coral reef ecosystem for the generations to come.
