THREAT DESCRIPTION OF THREAT POSSIBLE EFFECTS ON REEF

Shipping Accidents

1Shipping accidents are threats to the Great Barrier Reef, especially the traffic of several commercial shipping routes that pass the reef system every year. Between 1985-2001, 20 groundings and 11 collisions were reported, leaving behind debris and other foreign objects in the water. Boats have also been threats to the Great Barrier Reef, disposing their wastes and other foreign objects within the water.

2Ship wrecks left behind in shipping accidents destroy the habitats of marine wildlife and ecosystems within the waters in the Great Barrier Reef. These wrecks leave behind debris and other foreign material that remain within the waters for a long period of time, immediately affecting and destroying the surroundings within the ecosystem and habitats of many marine wildlife.

1Furthermore, when large sea vessels such as ships pass the reef they release toxic TBT compounds (Tributyltin) within the waters. This toxic released within the seawater is a threat and endangerment to not only the marine organisms within the reef ecosystems but to humans also.

Oil Spills 1Great Barrier Reef is the entry point for extensive oil and gas deposit. Though oil drilling is banned from the Reef, oil spills are often occurrences. About 282 oil spills have occurred between the years 1987-2002. 2Agencies have also increased allowable fines to a maximum to those shipping companies who have contributed to the rising problem of oil spills in the Great Barrier Reef.

2Oil spills have direct effect on the coral and marine life of the Reef. Though oil drilling is banned, oil spills are common such as that recorded in 2010 by the Chinese bulk coal carrier, travelling 10 km outside the regulation-shipping lane. It struck the reef, damaging native marine life while creating a massive grounding scar of over 3 km in length. Events such as theses have damaged the reef and make it inhabitable for marine life to survive. Recovery time, as experts understand may take between 10 to even 20 years.

3Longer exposure to the lower levels of oil within the waters when deposited by ships may kill coral. Oil is usually toxic for the corals in the waters and higher concentrations of the oil can result in death. Many marine animals such as butterfly fishes are also reliant upon such corals and the end to the coral can further lead to extinction of such rare species.

1 http://www.workincairns.com/great-barrier-reef/environmental-threats.asp2 http://www.greatbarrierreef.com.au/information/great-barrier-reef-threats/3 http://coralreef.noaa.gov/aboutcorals/facts/coral_oilspill.html

Water Quality and Temperature

The rising temperatures of the waters and the quality of the water within the Reef itself immensely affect the Great Barrier Reef. Both these factors play a large role in the contamination and polluting of water, affecting both the native marine wildlife and human recreational activities. Human wastes and chemicals are released into the air from nearby cities of Townsville and Cairns (near the Great Barrier Reef). Through the releasing and polluting of the atmosphere through such industrialisation actions, the quality of the waters is degrading.

4Temperature is the key factor in the controlling and spread of diversity within the marine wildlife at the Great Barrier Reef. It is vital in the controlling of the rate of coral reef growth and the maintaining of mutual relationship development among some marine wildlife. 5The excess burning of fossil fuels and other industrialising human activities are major contributors to the thinning of the ozone layer. This thinning is a contributor to global warming, and hence this warming impacts the daily temperature of the water temperatures at the Great Barrier Reef.

6Rising water temperatures will affect every aspect of the Great Barrier Reefs and its interconnected ecosystems within the water. Because of prolonged warm temperatures, coral reefs release colouring agents and leaving behind their white skeletons of calcium carbonate. This process is known as coral bleaching and is simply just one of the ways in which higher temperatures affect the Reef. Predictions by biologists suggest that if temperatures continue to rise then by the year 2030, coral reefs will have practically extinct. Statistics also suggest that a 2-3 degree Celsius temperature rise could put about 97%  of the reef in danger zone of bleaching each year.

In the process of the water contamination at the reef, the reef water is degrading and the water quality because a major issue of threat for the marine wildlife. Out of the 3000 coral reefs in the Great Barrier Reef it is estimated that approximately 400 are in danger of contamination because of the degrading quality of water. This degrading quality of the water is because of the chemical and agricultural wastes. However, many also believe that the degrading of the water quality is also caused by the increasing number of algae that pose competition in oxygen and light with the coral reefs.

The Crown of Thorns Starfish

The Crown of Thorns Starfish is the greatest threat on the Great Barrier Reef. It inhabits on the reef itself and gains its energy from feasting on the polyps (small growth or outgrowth) of the coral. While feasting it releases neurotoxins that absorb the tissue of the coral and literally “suck out” the reef’s backbone. The starfish is native to coral reefs in the Indo-Pacific region, playing an important role when feeding on the fast growing corals such as the stag horns and plate corals. This fast growing coral that got eaten away by the starfish would allow for the slower growing coral species to spread and form colonies, while helping to increase coral diversity.

12 Corals have declined by over 50 percent over the last 30 years and according to the research by the Australian Institute of Marine Science, Crown of thorns starfish are responsible for almost half of this decline. Outbreaks of the starfish occur cyclically over every 17 years. Just within the Great Barrier Reef there have been four documented outbreaks since the 1960s. Furthermore, these starfish spawn (releasing eggs) in the warmers months between October to February with the production of about 65 million eggs from large females over spawning season.

11 Water quality is also have said to impact the Crown-thorns conditions to thrive within an area. The water quality reduction caused by agriculture has promoted and allowed the starfish to thrive within its environment.

4 http://www.workincairns.com/great-barrier-reef/environmental-threats.asp5 ibid

6

Furthermore, the overfishing of the starfish’s predator, the Giant Triton, also contributes to the abundance of the crown-of-thorns starfishes and their impacts on the Great Barrier Reef.

Overfishing/ Illegal fishing

10 Besides tourism, the Great Barrier Reef’s fishing industry alone accounts for the gaining of a profit of 1 billion Australian dollars yearly. 12 The Great Barrier Reef supports the commercial, recreational, Indigenous and charter fishing, ranging from species including fish, sharks, crabs and even prawns. The Australian and Queensland Governments share the responsibility and management of fishing and its environmental impact of the Reef itself.  11 However through the protection of the Reef by the Marine Park Authority, areas of the reef are protected and catching dolphins, green turtles, whales and dugongs are prohibited.

10 Fishing becomes a threat to the Great Barrier Reef ecosystem when there is no limit to how many fish people actually catch and species are actually being endangered within the actual process. If people start catching rare and important species such as the Giant Triton, food chains can be disrupted and greater threats may arise to the Reef. For example, the fishing of creatures such as the Giant Triton can disrupt food chains and the Giant Triton’s preys such as the Crowns-of-thorns starfishes can increase in number, posing to be invasive species and threats to the Reef. Fishing also has a negative effect when boats, nets and anchors are signs of added pollution and destruction of coral reef habitat when them come to fish in the reef. 12 Even recreational fishing as it is promoted, in the year 2007, accounted for the six million fishes in the reef. Altogether the impacts of fishing are not so positive and pose to be a great threat for the Great Barrier Reef and its ecosystem.

Marine Debris 12 Marine Debris is rubbish that finds its way in the marine environment. It comes from both land and sea-based sources through which plastic is the most common within the Great Barrier Reef (50-90% of all debris item recorded). Most of the recorded debris consist of plastic bags, discarded fishing gear, plastic and glass bottles, rubber things, aerosols and drinking cans.

12 Marine debris can pose a navigation hazard for not only marine wildlife but to tourists and regular citizens within the waters of the Reef as well. This debris has the potential to transport chemical contaminants and transport invasive species. They can smother coral, entangling or even ingesting the wildlife. Not only can it cause deaths and injuries to the wildlife it can negatively affect financial gain earned from tourism and eventually threaten human health.

Extreme Weather Conditions