GREAT BARRIER REEF
The great barrier reef is a complex ecosystem off the coast of QLD, approximately 2300KM from Papua new guinea??™s fly river, north 8 degrees south to Frasier island and south 24 degrees. It covers an area of around 348 000 square kilometres which is larger then the UK, Switzerland and the Netherlands combined.
UNESCO (United nation??™s education, scientific and cultural organisation) named the Great Barrier Reef a world heritage site in recognition of the vast biodiversity. It is now the largest world heritage site in the world. 13 000 fish, 200 bird, 500 seaweed , 600 echinoderm(sea cucumbers and sea urchins), 125 shark/ray, 360 species of hard coral and 6 of the worlds 7 turtle species are found within the reef.
Coral is known for its brittle, vibrant coloured shades that make up the beauty of the reef. But this beauty can be easily taken away, like with harsh storms and cyclones. The reef is located in Australia??™s cyclone zone. These cyclones have been hitting the reef for thousands of years. This is how the reef is shaped and moulded. Large storm waves which are generated by strong winds due too intense low pressure systems mix together to create the reef to be damaged, reshaped and regenerate making more bigger stronger coral every time. During cyclones the water is tossed and churned up and around, this creates sediment or algae to become unsettled and causing it to settle down on potentional new coral where new polyps could settle. With the sediment covering the coral, this smothers it and kills off the new polyps. Also in the sediment contains harmful, toxic chemicals usually from farm and irrigation runoff this rises the turbidity in the water(making the water cloudy). Not only is sediment and contaminated sediment a problem so is fresh water from the inland, farms and towns/communities. Fresh water entering into highly salinitised areas will alter these salinity levels making it the wrong environment for certain species like fish to habituate in. sometimes this can be an advantage like with Tropical Cyclone Larry in March 2006, it showed it removed layers of accumulate sediment and reduced the water temperature.
Coral Reefs are made up mainly of Limestone. The limestone comes from the dead polyps when their skeletal remains it produces the limestone to make coral. These limestone figures are easily weathered and redistributed to other parts of the reef??™s ecosystem creating new landforms. The limestone creations are made to withstand the erosive power of waves and storms. As these reefs and/or coral structures die off the dead coral structure remains making it a perfect starting point for new coral to be born again and grow on top of the current reefs so new coral is forming on top of dead reefs expanding it more and more every day. Turbidity is defined by the cloudiness of the water. This is created by sand, mud, land runoff, farm runoff, contamination and algae. To much turbidity results in light not being able to penetrate the water and reach the reef??™s and this affects the process of photosynthesis. Coral rely on the sun as a form of energy, coral is mainly found in shallow, warm, oxygenated and the right amount of algae (turbidity) to survive. Starting with the shallow water the sun penetrates warming up the water and providing oxygen as the water is shallow there is less space for the sun rays to go, putting oxygen through the water which the coral and the polyps can live off, as well as tiny little organism??™s such as Zooxanthellae.
Within the coral there are more then 330 species of coral found within the great barrier reef a lot of it is in the northern section. Polyps are primitive organisms. Each coral reef will produce a single polyp it then reproduces itself to make a colony then the colony will gradually expand the reef upwards and outwards. Coral reproduction is quite unique, during spring they all reproduce at the same time. Other then coral the reef is also made up of thousands of individual species. With always recycling happening within the reef this has produced a higher rate of production compared to other parts of the ocean. The reef produces such species like, cnidarians, echinoderms, molluscs, crustaceans, mammals, reptiles, turtles, crocodiles, sea snakes and more. Dolphins and dugongs can be found on the reef all year round. With the whole abundance of species like fish in the reef this attracts a lot of birds aswell, these birds play an important role in transporting seeds from the mainland to the islands and vice versa.
Natural impacts are occurring on the reef every second of the year. It can range from tropical storms (as mentioned earlier), crown of thorne starfishes and also change of temperature. The crown of thirn starfish move their way through the reef, feeding and leeching off anything they can come across and most of this being coral, as they suck the nutrients and anything else on them off the coral is then turned white and this is know as coral bleaching. Also a number of these impacts can be caused by humans. This can come from run off from farms and inlands, this run off of water contains highly poisonous chemicals from irrigation used on the farms. As this reaches the reef it smothers the coral and animals living there and increases the amount of algae and turbidity. Climate change is associated with the green house effect.
Human impacts may also include:
??? Boating and commercial shipping:
The anchors on the boats damage the reefs when the boats drop these ripping and pulling the reef apart. Oil spills and rubbish thrown over deck pollutes the marine water and life. Some careless boat owners vent their sewage at sea. With around 600 commercial boats travelling through the hreef every year this increases all those chances of an oil spill and a higher rate of rubbish and pollution.
??? Over fishing
Many areas of the reef to this day are off limits to fisheries. But the reef still faces problems with illegal fishers who are fined a heavy cost and remain with heavy penalties.
Research conducted by James Cook university in Cairns show that tourism has five broard impacts on the reef, these include:
1. coastal tourism development: puts a strain on estuarine river systems
2. island based tourism: problems associated with sewage and rubbish dumps.
3. marine based activites: rubbish, oil spills and mooring resulting in anchor damage
4. water-based activities: tourists like divers and snorkellers sometimes get too close to the coral and it brakes off.
5. wildlife interactions: an impact on animals impacts the breeding cycles and natural interactions.
??? Land clearing
Agriculture, urban development and aquaculture(fish farming) can all effect the quality of water that runs from inland into the reefs. Coastal development next to reefs is expanding by large amounts, this is due to tourism sites, resorts, hotels etc??¦ the clearing of wetlands impacts on the sustainability of the reef. Estuarine and intertidal wetlands provide important habitats and nurseries form many parts of the species that form part of the reef ecology. Also landclearing results in eronsion of topsoil, increasing the turbidity.
Prawns, several fish, pearl and edible oysters are all being farmed on or next the reefs. These farms release chemicals and diseases that impact on the wild life like the inland run off. The use of chemical fertilisers produce nutrients that increase algae growth and then the algae smothers the reef and reduces light penetration.
More then 35 groups of aboriginal or torres straight islanders have an important part of traditional links and connections to various parts of the reef and the surrounds its in. they have harvested as hunters and gatherers up and down the coast of qld.
In 1992 the high court decided that aborignals and torress strait islanders had rights over many of there tradtional lands