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Ecosystems At Work:

The Great Barrier

Liam Bleakley

Table of Contents

Title Page…………………………………… Page 1

Table of Contents…………………………. Page 2

Introduction……………………………….. Page 3

Geographic Location…………………….. Page 4

Biophysical Interactions……………….. Atmosphere…………………………………. Lithosphere…………………………………. Hydrosphere………………………………… Biosphere……………………………………..

Page 6 Page 6 Page 6-7 Page 7 Page 7-8

Stress: Vulnerability and Resilience… Human-Induced Stress…………………. Natural Stress………………………………

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Page 8-10

Page 10-13

Figure 8.0………………………………….. Page 12

Management Strategies…………………. Traditional Management……………… Contemporary Management……..…..

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Page 14-17

Conclusions………………………………… Page 17

Bibliography……………………………….. Page 18

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Introduction The Great Barrier Reef is the only natural structure that can be viewed from space. The reef stretches over 2,300 kilometres and has an area of around 344,400 km2, almost double the size of the next largest coral reef. The sheer natural beauty of the 2900 individual reef systems, 100 exotic and unique islands and vast number of fish species contributing to the genetic diversity of the reef has earn’t it a spot as one one the seven natural wonders of the world.

The reef is located in the Coral Sea, only a few kilometres off the coast of Queensland, Australia. The physical structure of the Great Barrier Reef provides local micro-climates and is home to many rare aquatic species making it one of the most biological diverse places on earth . The extent of this 1

ecosystem enhances the amount of biophysical interactions that occur. The Great Barrier Reef is a very fragile ecosystem that has been created through complex interactions within the biophysical environment over time. However, this Coral Reef Biome is under a huge amount of human induced stress due to water pollution, over fishing and oil spills.

Around forty Aboriginal and Torres Strait Islander tribal groups have territories located around the reef, thus traditional management strategies such as setting size limits on fish caught and assigning sacred animal totems to Indigenous groups to take responsibility of that animals survival have been enforced for thousands of years. More contemporary management strategies such as zoning have been recently conducted due to an increase in the amount of coral dying. These traditional and contemporary management have been slowing the effects of climate change on the reef however, more needs to be done in order to make the reef a sustainable recourse. This report aims to display the interactions between the biophysical environment as well as evaluate the management strategies but in place by the commonwealth government.

http://travel.nationalgeographic.com/travel/world-heritage/great-barrier-reef/#/great-barrier-reef-1

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Geographic Location The Great Barrier Reefs climate is warm all year round as it is located within the tropic of Capricorn and the equator. The reef is located off the North Eastern coastline of Queensland, Australia. The reef starts just south of Papua New Guinea at around 8 degrees south latitude in the north and stretches to 24 degrees south latitude in the south. The Great Barrier Reef is significant as it is by far the largest coral reef in the world and is home to 1625 different fish species . Many micro-climates 2

exist within the Great Barrier Reef, these include five different types of coral reef (figure 1.0).

The coral reef’s extent is similar to the total area of Italy, Germany or Japan. Due to the huge extent of the reef there are a total of 14 coastal micro-climates that are vital to the functioning of the reef. These include coral reefs, the lagoon floor, islands and open water. The movement of specimens within these environments cause ecotones within the Great Barrier Reef causing the reef to have a high ecosystem diversity. This reef is international recognised for its diverse number of species and habitats.

The world heritage boundary covers the entirety of the reef stretching from the most northerly point in mainland Australia to just north of Bundaberg(24º 29’ 55”S - 154º 00’ 04”E) (Figure 2.0). An estimated 2.4 million tourists visit the Great Barrier Reef each year. During the years of 2011-12 the value-added economic contribution of the Great Barrier Reef World Heritage Area to the Australian economy was $5.68 billion, generating more than 69,000 full-time equivalent jobs . 3

http://www.gbrmpa.gov.au/about-the-reef/facts-about-the-great-barrier-reef 2

https://www.environment.gov.au/sustainability/publications/economic-contribution-great-barrier-3

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Figure 1.0

Page �5Figure 2.0

Biophysical Interactions Each of the four spheres play a vital role in the survival of the Great Barrier Reef as the events that take place in these biophysical environments can drastically alter the way the reef looks and operates.

Atmosphere: The Great Barrier Reef is located within Australia’s cyclone zone. For millenniums intense storms and tropical cyclones in the atmosphere have defined the reef ecosystem. The impact that a tropical cyclone has on the reef is dependant on the duration and intensity of the storm. The atmospheric temperature greatly effects the growth of coral. The ideal temperature for coral is between 20 and 27 degrees celsius. If the water temperature drops bellow 20˚C the zooxanthallae cannot produce the much needed limestone (the dead skeletal remains of coral polyps) therefore, if water temperatures rise above 27˚C a bleaching effect on the coral will take place as the zooxanthellae will leave the coral polyp. There is a very delicate balance to maintain the equilibrium of the reef. This interaction between the atmosphere and lithosphere is one of the most evident issues that the coral reef is faced with as warmer waters are a natural response to a human induced stress known as climate change.

Lithosphere: The lithosphere holds a very important role in the survival of the Great Barrier Reef as it is responsible for forming and transforming the reef ecosystem. The reef itself produces solid limestone which protects the coral reef systems from the erosive force of waves.

The process of subsidence severely impacts the growth of coral as the optimal conditions for coral growth relies on the depth of the water. Subsidence is where the lithosphere sinks through the sediment or a heavy weight has been placed on a specific area. When land subsides the lithosphere may interact with the biosphere as coral reefs are able to form in an aquatic ecosystem. However, coral can die if an area of land subsides to

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much. Sediment has an important influence on the Great Barrier Reef. Sediments such as mud are evident in the reef due to the effect of surface runoff from on land agricultural sites. If sediments such as mud and sand are disturbed they can cloud the water, creating turbidity. This can result in less light penetrating the water therefore, a f f e c t i n g t h e p r o c e s s o f photosynthesis.

Hydrosphere: The rate of biodiversity greatly depends on the amount of wave energy. Coral reefs tend to thrive best where there is a high wave energy. The lithospheric structure of the reef is very effective at interfering with wave energy. The seaward part of the reef absorbs most of the wave energy thus creating an area of calm water behind it. The direction of water flow tends to be towards the north for about nine months of the year, this is due to the Trade Wind Drift Current specifically, the South Easterly Trade Winds. However, during the summer months, the monsoonal conditions result in a reversal of this flow of water which is influenced by the East Australian Current that moves the water in a southerly direction (figure 3.0). This reversal of water is pivotal to the biodiversity of the reef ecosystem as the highly saline, warm waters flow down from the north down south bringing high nutrient levels, contributing to the diversity of life on the reef. These currents are also used by many marine species to migrate for breeding.

Biosphere: The growth of coral strongly relies on the interactions between the hydrosphere and biosphere. The depth of water impacts the growth of coral as zooxanthellae needs to photosynthesis. In order for this to efficiently occur, the coral must be between 2 and 30 meters deep in the water as this is where the light is strongest. Water temperature between 26˚C and 27˚C is best for coral polyps to create their limestone exoskeleton. If the water temperature falls below this a build up of limestone can occur.

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Figure 3.0

Coral thrives best in clean water with low concentrations of chemicals such as nitrogen, ammonium and phosphate. Phosphate interferes with the development of the corals skeletal structure. The salinity of the water also impacts coral growth. If there is a sudden drop in salt levels coral can die. This usually occurs after heavy rainfall in the atmosphere resulting from a tropical cyclone. This can make fresh water ponds on top of reefs causing coral death. Corals do best when the water is constantly being oxygenated by wave activity on the outer edge of the reef. Millions of tiny air bubbles are released into the water as a wave crashes down on a reef.

Stress: Vulnerability and Resilience:

Human induced Stress: Humans have been using the Great Barrier Reef for thousands of years. The resources of this reef were accessed by canoes made by Aboriginal and Torres Strait Islander peoples before European settlement. Over the years the Great Barrier Reef has been put under a tremendous amount of human induced stresses. Issues such as overfishing, water pollution, global warming and tourism damage impact the functioning of this ecosystem.

Climate change is associated with the greenhouse effect, this has the potential to significantly impact the Great Barrier Reef and many other reef systems throughout the world. The primary human activity affecting the rate and amount of climate change is greenhouse gas emissions from the burning of fossil fuels such as coal and oil. This has caused the Earth’s surface temperature to rise. Climate change d i r e c t ly i mp a c t s m a ny s p e c i e s o f fi s h , invertebrates, birds and m a m m a l s a s w e l l a s terrestrial and aquatic plants. The impact of the function of the reef from climate change is inescapable. Therefore, almost all species will in different ways be adversely impacted by

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Figure 4.0

climate change. The most significant impact that climate change has on the hydrosphere is the increase of water temperature (Figure 4.0). This will affect the movement of water in the vast ocean currents that act as part of the biophysical nutrient cycle on the reef. As global warming worsens, more carbon dioxide from the atmosphere will be dissolved in the water, changing the chemical structure of the reef. This chemical issue coupled with rising sea levels, could be enough to completely destroy the reef, concluding the collapse of the reef ecosystem.

Due to the increase in greenhouse gases as a result of excess fossil fuel burning, several sea bird species are declining across parts of the Great Barrier Reef. Failure of eggs to hatch and mass mortalities has been evident in a number of rookeries of sea birds. The amount of food that the reef has to offer is declining as a result of overfishing. These sea birds are faced with the direct impact of this as scientists believe that the failure of eggs hatching is a result of ‘provisioning failure’, meaning that the adult birds are having to travel too far to find food . This results in a decrease of species diversity. 4

The Great Barrier Reefs biophysical ecosystem has been put under a lot of stress due to commercial fishing. The reefs fishing industry is worth more than $400 million annually to the local economy . Scientist believe that a minimum of 25% - 5

30% of the great Barrier Reefs marine park must be protected from commercial fishing in order to be sustainable. However, only 4.6% of the reef is actually protected. Due to commercial and recreational fishing occurring in more that 95% of the reef the impacts have been quite severe. Prawn trawling occurs in just over 50% of the marine park causing great disturbance to the sea floor. This increases the turbidity of the water, slowing down the process of photosynthesis. This may cause the aquatic plant life to die therefore, resulting in a lack of nutrients in the water. Bycatch is needlessly killed in the process of prawn trawling.

“Global Interactions” (2013) Page 984

http://www.mrstevennewman.com/geo/GBR/Human_Impacts/fisheries.htm 5

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Humans tend to collect rare and precious things for personal pleasure. This has resulted in the over-collection of some species, upsetting the natural balance in the ecosystem. The triton shell is prized by marine collectors. This aquatic organism is a natural predator of the crown-of-thorns starfish, the over-collecting of this aquatic species has resulted in the increase in population of the crown-of-thorns starfish . 6

There are many commercial ships that pass through the Great Barrier Reef each year. There have been two reported groundings of large container vessels over the past 3 years, these were due to negligence which released large oil spills. Oil spills increase turbidity in the water, greatly reducing the rate of which aquatic plant life photosynthesise. This can effects the way the aquatic biophysical community function.

Natural Stress: The Great Barrier Reef is a complex ecosystem that has many natural stresses on the reef. The atmosphere holds some of the most major stresses to the function of the reef. Topical cyclones are a major source of damage to the reef system. As a result of these storms and high winds, large waves are created that damage the reef.

The human induced stress of climate change has led to an increase number of tropical cyclones hitting the reef. This natural stress was brought on by a human induced stress, climate change. If the rate of anthropogenic global warming continues, scientist believe that by the end of the 21st century tropical cyclones globally will be 2 to 11% more intense on average (figure 5.0). This would imply an even 7

greater percentage increase in the destructive per topical cyclone, this is assuming there is no reduction in storm size. With tropical cyclones comes heavy rainfall. This rainfall can

http://www.mrstevennewman.com/geo/GBR/Human_Impacts/threatened_species.htm6

https://www.gfdl.noaa.gov/global-warming-and-hurricanes/7

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Figure 5.0

lead to flood plumes and lowered salinities that stress and kill sensitive aquatic biological communities such as seagrass and coral. Widespread physical damage to the reef can also be a result of strong waves and currents generated by extreme velocity winds. In addition to this, the direct impacts of mobilised boulders and coral rubble as a result of the tropical cyclones energy cause impacts to the reef organisms and the underlying reed substrate.

Coral bleaching is a natural response to stresses placed on specific areas of coral c a u s e b y c h a n g e s i n t h e a q u a t i c environment. There are many possible causes of coral bleaching however, in recent years the increased number of coral

bleaching appears to be the direct result of warmer sea temperatures. The bleaching of coral is created when the symbiotic relationship between the zooxanthellae and coral polyp breaks down, causing the coral to expel algae. This results in coral losing it’s distinctive colour that the zooxanthellae was once providing.

In 2011, tropical cyclone Yasi ripped through an area of 89,090 km2 of the Great Bar rier R eef causing a tremendous amount of physical damage to the reef systems and putting a lot of stress on the species diversity of the reef. This category 5 storm tore its way through north-eastern Australia (Figure 6.0) . A scientific report displaying the scale and spatial patterns of the damage was published in late 2011 . As a result of this tropical cyclone 8

slightly over 15% (3,834 km2) of the 24,839km2 of reef area within the great Barrier Reef Marine park was estimated to have sustained some level of damage to the coral. Microclimates located within the path of this tropical cyclone were most affected, this includes the 61 coral reefs that were in the destructive path. 95% of these reefs suffered severe

http://www.gbrmpa.gov.au/__data/assets/pdf_file/0008/8783/8

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Figure 7.0

Figure 6.0

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Figure 8.0

damage to living coral communities, structural damage was also evident at 78% of reef systems that were exposed to high winds, specifically those that were located south of the cyclone eye (Figure 7.0).

Other natural stresses are also present in the biosphere. The Crown-of-thorns starfish has the potential to cause widespread degradation of reef systems as it consumes substantial amounts of coral. Due to the human induced stress of collectors killing tritons for their prized shell, the crown-of-thorns starfish population has drastically increased as the triton was a natural predator of this aquatic species. In some cases the Crown-of-thorns starfish has reached plague numbers making the naturally occurring series capable of more widespread damage. However, eventually the starfish eats so much coral that their main food supply becomes exhausted resulting in the number of starfish returning to a normal level. These natural impacts have resulted in significant stress on the Great Barrier Reef therefore, labelling the reef as an ecosystem at risk.

Management:

Traditional Management Strategies. In order to combat the human induced stress of overfishing local Aboriginal and Torres Strait Islander communities are given specific areas of land/reef to manage. For an estimated 50,000 years these spiritual pieces of land were well managed as the Aboriginal and Torres Strait Islander peoples believed that they were not above nature but apart of it. Thus, the main traditional management strategy at the time was to focus on using terrestrial and marine resources in a sustainable way. They only took enough resources from the reef ecosystem to satisfy their specific needs, in doing this the dynamic equilibrium that exists on the reef was not disturbed. This management strategy was very effective as fish species could remain plentiful throughout the year as well as the species diversity of the reef remained high. Sustainable fishing was achieved through detailed practical knowledge of the reef ecosystems, its habitats and natural history as well as seasons

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and animal migration patterns. This detailed knowledge led to the indigenous peoples setting size limits on fish they had caught, this prevented overfishing and is an cost-effective management strategy. Seasonal hunting was also implemented to stop aquatic species from going extinct, this allowed species to recover and be plentiful for the future. These traditional management strategies help to reduce the stress of this ecosystem by reducing the amount of fish caught and minimising the extinction of aquatic fish species therefore, reducing the risk on this ecosystem.

Most Indigenous groups have a sacred totem like the stingray or dugong. It is their responsibility to look after these animals. This is known as Totemism. If a groups totems is a dugong then that group is prohibited from killing or eating that animal. Individuals had to perform rites in order to ensure the continued proliferation of the groups totemic species. This was a relatively effective form of management as the ecosystem remained reasonably unchanged for thousands of years. The ecological diversity of the reef was maintained as no specific species was targeted by a community as a primary food source. Totemism resulted in no one animal or plant being over-hunted as a variety of different food sources were used by different Aboriginal and Torres Strait Islander communities to ensure that members were not consuming a taboo animal or plant.

Today, Indigenous Australians still have a major role in the management of the Great Barrier Reef. In 1995, the Indigenous partnerships Liaison Unit was established by the GBRMPA to work in collaboration with Indigenous Australians in order to better mange the reef, this also allowed tradition management strategies to continue. Indigenous people with extensive knowledge are helping scientists with their research and protection of the reef. Several Aboriginal and Torres Strait Islander communities are involved in co-management processes with managing agencies in the Great Barrier Reef area adjacent to their territory. These indigenous communities have a variety of roles that include providing vital practical

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local knowledge required for making decisions, such as which areas of reef are best zoned for different activities.

Contemporary Management Strategies. The Great Barrier Marine Park Authority (GBMPA) is the main agency that advises the commonwealth government on the management of this world heritage site. In the past 20 years scientists have seen a major increase in the stresses that this reef ecosystem has been put under. This ecosystem is at risk of dying if management strategies are not effectively conducted. This marine park is governed by the commonwealth government of Australia. Many treaties and legislations passing laws to manage the reef have been put in place by this government.

In order to effectively combat the effect of coral bleaching the problem must be managed from the core of the issue. Warmer sea temperatures have caused mass bleaching among coral in the Great Barrier Reef. Warmer sea temperatures have been caused by the human induced stress, climate change. Many nations have come together in order to combat climate change in order to protect the worlds oceans.

At the climate conference that was taking place in Paris in December 2015, an astonishing 195 countries adopted the first ever universal, legally binding global climate deal . This 9

legislation is formally known as the ‘Paris Agreement’. The agreement displays a global action plan to put the world in the right path to avoid dangerous and threatening climate change by limiting global warming to well under 2˚C. Governments agreed to mitigate the issue of rising sea temperatures and to aim to limit the increase to 1.5°C, this would greatly reduce risks and the issues associated with climate change. The undertaking of rapid action in accordance to the best available science to prevent climate change was unanimously agreed on. This treaty states that every 5 years the leaders of the countries involved must come together every 5 years to set more ambitious targets as required by the latest scientific

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research. Each country must report with each other and the public on how well they are doing to implement their targets . 10

The tracking of progress towards long term environmental goals was also agreed on through the ‘transparency and accountability’ part of the Paris Agreement. This phenomenon is managed by the European Union. The EU is at the forefront of international efforts towards a global climate change deal. The European Union was responsible for building a broad coalition of developed and developing countries in favour of the Paris Agreement, this resulted in the successful outcome of this treaty.

These efforts to stop climate change will evidently result in colder sea temperatures therefore, less coral bleaching will occur. This will drastically reshape the reef ecosystem as there will be fewer tropical cyclones destroying key parts of the reef. The natural currents will no longer be affected by changing sea temperatures resulting in migration patterns to be re-established, this will bring much needed nutrients to the Great Barrier. This is a much needed management strategy as it involves the whole world not just the Great Barrier Reef, this is the most important management strategy currently active.

The water quality of the Great Barrier Reef has been in the decline in the recent decades as tourism increases. Research conducted by the Queensland Government discovered that many of the fringing reefs are being degraded by poor water quality. This led to the creation of the Reef Water Quality Protection Plan in 2003. This plans main goals are to reduce the amount of water pollutants entering the Great Barrier Reef as well as to rehabilitate river catchments and then better manage them. The Reef Plan recognises the need to create key partnerships with specific interest groups, such as both the local and scientific community as well as local farmers.

Some of these plans are already in place. The regional plans to better manage river catchments has been developed. This

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involves strategies to reduce pollutants and sediment runoff. Major catchments such as the Barron catchments is already benefiting from these initiatives.

The announcement from the GBRMPA about the creation of the Great Barrier reef Marine Park Zoning Plan was a positive sign as it aims to increase the water quality of the marine park as well as keep the aquatic biological community safe from tourists. The plan was developed to allow selected human activities to take place within the park while not degrading the overall ecosystem. This resulted in commercial fishing to be prohibited in some parts of the reef and tourist construction projects, such as pontoons, to only be built in specific areas on the outer reef. The aim of this Plan is to ensure the intergenerational equity of the reef is achieved while allowing the present generation access to the resources of marine park. This plan is vital in keeping the reef ecosystem healthy and eliminating any risks.

Conclusion: The Great Barrier Reef is an ecosystem at Risk, and is in serious need of effective management strategies. The human induced stress of climate change is the main factor that is increasing the risk of this reef ecosystem. Climate changed is linked with more frequent natural stresses such as tropical cyclones. If these stress persist, the reef will suffer major physical damage resulting in the loss of habitat to many aquatic species. However, management strategies such as global environmental treaties have recently been put in place in order to combat the effect of climate change. Other traditional management strategies such as fishing sizes are contributing to the management of this reef. These management strategies are both effective and vital to the survival of the Great Barrier Reef. Without serious help this reef may not be alive for further generations to see. With aid from other countries the Great Barrier Reef can one day return to its natural, healthy state.

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Biliogrpahy

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Working together today for a healthier Reef tomorrow... (n.d.). R e t r i e v e d D e c e m b e r 0 1 , 2 0 1 6 , f r o m h t t p : / /www.gbrmpa.gov.au/about-the-reef/biodiversity

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Working together today for a healthier Reef tomorrow... (n.d.). R e t r i e v e d D e c e m b e r 0 1 , 2 0 1 6 , f r o m h t t p : / /www.gbrmpa.gov.au/about-us/legislation-regulations-and-policies

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