What Are The Greatest Environmental Threats To The Great Barrier Reef And What Are Their Solutions?

1.0 Introduction

The Great Barrier Reef (GBR) is the world's largest reef and is regarded as one of the world's greatest natural treasures. It is located on the northeast border of Australia which extends 2000 kilometres and covers an area of 35 million hectares. It was formed 500, 000 years ago as reefs are formations of billions of coral polyps and structure of reefs were built by living creatures. With the help of algae, sponges, organism, combined with cementation processes, reef structure will stabilise as this procedure contributes to the growth of coral. The GBR is important due to the reef's ecosystem supporting a diversity of marine life, providing shelter, food and protection. According to the studies of Diving Cairns (2003), the ecosystem provides habitats for a variety of marine life including 1,500 species of fish, 350 different kinds of coral, 4000 species of molluscs and 10,000 species of sponges. The area is of significance for the birth of humpback whales and nesting groups for the endangered green and loggerhead turtles.

As well as ecological and natural importance, it is also of cultural and historical significance with humans as it contains archaeological sites of Torrens Strait Islander origin, containing over 30 historical shipwrecks in the area (Diving Cairns, 2003).

Due to environmental and human impacts, the GBR is under great pressure where any slight change or interference towards the natural growth of corals will lead to a rapid decline of reef coverage. Gilliam (2007) states without any protection, almost three quarters of the world's reefs would die within 50 years. The greatest environmental threats resulting from the damage of the GBR are bad water quality, overfishing, oil spills, recreational diving, and carbon dioxide produced by coastal development. Even though a large part of the GBR is protected by the Great Barrier Marine Park (GBRMP), further damage towards the marine ecosystem is still taking place. These threats will be further examined and explained referring to the cause of the threat, the effects it has on the reef and solutions to stop further damage to the Reef.

2.0 Environmental and Human Impact

There are currently lists of environmental and human actions that have contributed to the damage towards the GBR. The main threats are pollution in the waters of the Reef which is caused by a series of actions to the contaminant of water, overfishing which is a major contribution to the disruption of the food chain, oil spills from large ships, physical destruction of coral reefs caused by recreational diving, and carbon dioxide produced by coastal development. There are many threats that have resulted from the damage of the GBR, but there are also many solutions to tackle and prevent the GBR from rapidly declining.

2.1 Water Quality from runoff

Queensland Premier, Anna Bligh (2007), reports that the water quality on the GBR is not improving. Runoff is water flow on land where excess water and other sources such as waste, impure chemicals and soil contaminants are collected, then get washed into the open water. Chemical runoff from agricultural development, copper pollutants from industries and land construction of building roads, buildings or bridges, contribute to an increase in runoff. As well as a loss of coastal wetlands, which act as natural filters to stop chemicals from entering oceans, water quality of the GBR is exposed to having large quantities of runoff leading to a higher risk of damage towards the Reef.

Pollution in the waters of the GBR results to greater damage towards the health of the marine ecosystem. The consequences of water contamination include increase in water temperature, increase in pesticides, salinity, and increase in acidity of water. High temperature of waters puts stress on corals and can lead to coral bleaching. New Scientist's article (2002) "Coral Reefs Bleached" reports bleaching is the response to heat stress within coral, which causes coral polyp to expel their algae, resulting to a loss of colour and loss of intake of nutrients. Contamination of water alters the metabolic processes of species. Genetic mutations within marine life could occur or death, which results to an unbalanced ecosystem. An infectious disease on coral reefs, caused by water pollution, may also arise. Larry (2006) states that water pollution is linked to the outburst number of crown-of-thorn starfishes. The increased number of crown-of-thorn starfishes contributes to a loss of coral coverage. A possible negative outcome of excess nutrient concentrations is the increased growth rate of phytoplankton. The presence of phytoplankton puts coral reefs in danger as the increased number of the filter feeding organisms will compete for space.

The Reef Water Quality Protection Plan Secretariat (2009, p8) states "improving the water quality of the Great Barrier Reef will produce healthy ecosystems which can recover from acute disturbances or even continual stressors". Ways of improving water quality of the GBR include reducing the load of pollutants and chemicals from entering the water by better management of coastal development, eliminate waste dumping and debris in water from ships, and reduce runoff from entering the water. Recycling, litter control, water conservation, and informing others to contribute in improving the water quality, can help save the coral reefs of the Great Barrier Reef. Marine ecologist Richard Unsworth (2010) suggests improving and increasing the area of seagrasses is important as seagrasses are critical in supporting biodiversity and fisheries productivity, and also are the sole food for dugongs and marine turtles.

2.2 Overfishing

Fishing is known as a popular recreational past-time to get in touch with the natural world (GBRMPA, 2008). World's Resource Staff (2000) claims over fifty-eight percent of the world's reefs are threatened by human activities, overfishing, destructive fishing practises, which pose as the greatest threats to the reefs. Unsustainable overfishing of protected species, such as the Great Triton and sharks, can cause disruption to the food chain. The effects of overfishing are reef habitat destruction, increase of crown-of-thorns starfishes, and pollution by boats. Coral reef and seafloor destruction is caused by high levels of fishing pressure from the use of anchors, trawling and nets. Fishing practises in trawling can lead to by-catches of unwanted species, like sea turtles and dolphins, and may even endanger species or possibly cause extinction (WWF, 2004). A disruption to the food chain causes an unbalance to the marine ecosystem. For example, a decrease of predators will result to an increase

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