The following is a major report that I compiled while being assigned a project to develop strategies to improve the ecosystem of the Great Barrier Reef.



          Aquatic biomes possess some of the most diverse organisms that have ever been seen on planet Earth. Its biodiversity extends from the intriguing array of mollusks that inhabit the shallow rivers of the world to the mysterious cephalopods that roam the deepest regions of the ocean floor. But nowhere is aquatic biodiversity its richest but in the Coral Reef ecosystem that is found in the tropics. The Coral Reef ecosystem contains within it intricate ecological relationships between the organisms that call the reef home, such relationships allow many species of fishes to survive and also serves many purposes for terrestrial animals such as human beings. Man has always searched the sea for resources and had for thousands of years obtained food from the ocean and in today’s world coral reefs have served an aesthetic purpose that drives the economy of many developing (and developed) nations.


Today in the 21st century, scientists are looking at coral reefs as being a source of pharmaceutical drugs. Corals reefs also possess a very impressive ability that few ecosystems possess: the ability to regenerate from major disturbances. However in recent years, there has been a surge in pollution levels from human related sources such as excessive nutrient run-off that intensifies the problems of coral destruction in shallow corals and the dumping of industrial wastes such as hydrocarbons and oil spills. This report will serve to outline the importance of protecting the corals since it serves as a foundation for the entire ecosystem. It will be done by using Australia’s Great Barrier Reef as the model and proposing management strategies that can be implemented in order to offset the two major problems listed and restore the corals to its original condition.



          The Great Barrier Reef is the world’s largest coral reef. It is composed of more than 2,800 reefs and 900 islands that stretch for 2,600 kilometers covering an area of approximately 344,400 km². Managed in part by the Australian government and the Great Barrier Reef Marine Park (GBRMP), the Great Barrier Reef is often referred to as the single largest organism in the world and one of the seven natural wonders of the world (CNN). Environmental issues were not of large concern to scientists for many years and one may probably wonder why since it is clearly at the top of the agenda today. This is mainly due to the location of the GBR (Great Barrier Reef) which is located just off the coast of Queensland, Australia.

           Queensland is a highly de-centralized state with an accommodating and pleasant climate conducive to coastal settlement. Areas near the coast are among the fastest growing population centers in Queensland and encompass all but two of the state’s major ports. Taking this into consideration, one can infer quite accurately the entire scenario from past to present. In recent years this increase in population density around the Queensland coast has brought with it aesthetic pleasure for its residence and tourists but has also brought immense environmental problems to the coral reefs which is intensified by greater factors due to global warming. The main environmental problems associated with this rise in development and population density include vegetation modification, grazing (which can eventually lead to unstable land and hence nutrient run-off), urban development, and industrial development and aquaculture problems ( These problems combined create a synergistic effect which has caused decline of the coral reef ecosystem in the past decade. However, despite the synergistic effect there are two particular issues that are of most importance and may be considered as the two major factors contributing to coral reef degradation and they are the effects of industrial pollution particularly non-renewable resources such as oil and nutrient buildup in catchment areas and discharge into nearby streams which can eventually deposit these extra nutrients into the coral reef ecosystem.

            To properly manage the coral reef ecosystem and suppress these man-made disturbances, all the strategies proposed and implemented must be sustainable in that they must all be able to benefit not only the corals but be able to sustain the economy of the country (the Great Barrier Reef is one of the largest contributors to the Australian tourism industry) for present and future generations. Identification of the interrelationships of the corals and the environment (pH, temperature, turbidity, e.t.c) is fundamental to proposing a management strategy that can be sustainable and hence this symbiotic relationship must be incorporated within the strategy being designed. This concept will be highlighted throughout the research paper.

With an overview of the Great Barrier Reef and the implications of human development on the reef, one may ask the question: “Why should we care?”

The Great Barrier Reef is not only important to the nation of Australia but it is important to the world. The most important value coming out of the GBR is that it is a large reservoir for biodiversity. As mentioned above, the GBR’s biodiversity rivals that of the world’s greatest tropical rainforests and if the corals that inhabit this reef were to die, then the domino effect would be the destruction of this biodiversity hence depriving the world of many rich species and even possible secrets which lie within the corals such as future medicinal drugs.


(taken from


            Hydrocarbon ejection into nearby waterways is an extreme example of terrestrial run-off, extreme in the sense that these pollutants, according to the Great Barrier Reef Marine Park Authority are labeled as “other” pollutants. This gives mix messages to the public and some may even say that the authorities are trying to deviate and narrow the minds of the people towards what they consider as real threats such as over fishing. But these “other” pollutants are actually the most dangerous of them all and if hydrocarbon dumping is continued exponentially, it may cause irreversible damage to the coral reefs. Fortunately, according to research articles by the Australian Institute of Marine Science, polyaromatic hydrocarbons are usually found in low concentrations which may be indicative of a relatively unpolluted environment. The problem here lies in the fact that pollutants like hydrocarbons may not have a short-term effect on corals but may contribute to a long-term effect and this in turn can cause permanent damage to the reef. Hence, even if these chemicals are found in low concentrations, it must be dealt with immediately.

The Australian government has imposed regulations on factories that restrict certain methods that may involve the release of pollutant discharged into nearby waterways which can eventually seep in the marine environment and affect the nearby reef. They have also placed restrictions on where these factories should be sited relative to the coastline. It is this law that should be taken and analyzed since it is clear that though this law is being enforced well, hydrocarbon pollutants are still being discovered in the reef system as low as the concentrations may be.

            Another modern industrial problem which may cause severe damage to coral reefs is the effect of oil spills on the Great Barrier Reef. Oil drilling is not permitted on the reef however it remains as one of the biggest threats to the reef with a total of 282 oil spills between 1987-2002. Great Barrier Reef Marine Park Authority 2006)

            It is not hard to imagine what would happen to the corals because of oil spills and polyaromatic hydrocarbons. The properties of both these pollutants particularly oil include having a density higher than water which can cause it to sink below the surface when it is ejected. This results in the formation of a “pollutant cover” that can separate the corals and algae from the area of light penetration. Since light cannot penetrate, this sharply reduces photosynthetic activity of the primary producers and this can cause multiple effects; destruction of all the organisms which exist at trophic levels higher than the producer level and can ultimately destroy the corals since the algae is in a crucial symbiotic relationship with the coral. However, what is even worse is that since the producers are destroyed it can result in a situation whereby succession can be restricted resulting in a permanent desolate area of destruction and emptiness.


(taken from



            After reviewing the threats of industrial pollution on the Great Barrier Reef, one can now proceed to propose management strategies which can prove to be sustainable and effective. As mentioned earlier in this report, Coral Reefs can be analogized to terrestrial biomes, specifically the tropical rainforest. Many countries around the world have been able to protect the richness of their rainforests and the methods have been proven successful, so the question one may ask is: “Can similar management strategies be applied to the coral reef ecosystem especially since both biomes are very similar in terms climatic conditions?” The answer is yes.

            Strategies which have been used on terrestrial habitats can be applied to aquatic systems though certain aspects of the methodology may have to be altered. The use of an aquatic quadrant can be applied. In forested areas, quadrants are set up, and in each quadrant, everything within it is analyzed and sampled. In the Great Barrier Reef, similar quadrants can be laid out near the most vulnerable areas, after which each quadrant can be analyzed using a particular method known as the calculation of Species Richness. By knowing this value, one can then determine on a scale, the condition of the habitat and hence how healthy the corals are.

 The following is a hypothetical situation in which Quadrant analysis can be applied: 

            Quadrant analysis will require four vessels which are to be used to stabilize the quadrant so sampling in each quadrant is more accurate. The quadrant is placed at X, Y and Z km from the shoreline, this is because the length can be recorded, and so there will be no overlapping when another area is to be analyzed. Because it can be very long and tedious and also inaccurate in calculating the HSI of a coral reef system, another method known as the calculation of species richness can be used to determine the health of the reef.


E.g. the following is the calculation of the species richness of Quadrant 1 in the hypothetical data that was accumulated in the previous map sketch:


In the 100 m2 quadrant, there was a report of 2 flounder fish, 3 reef sharks, 4 lobsters and 6 crabs:

The species richness for this quadrant would be as follows:
































There are 4 species. Therefore, species richness = 4.
There are 18 individuals.
H' = -SUM{ pi*ln(pi)} = -(-1.186) = 1.186

where, p(i)= the relative abundance of species i and H’ is the species richness.

If the value of H’ is high then it means that the species richness is high, if it is low; it means the species richness is low. From the calculations, we can infer that Quadrant 1 contains low species richness. This calculation can be applied to the other 17 quadrants and the mean H’ value can be calculated. If this value falls in the range of the value of H’ then it means that the area of the reef located X, Y and Z km from the coastal zone has low species richness and hence poor coral population. This can then be compared to another set of quadrants and again if the value of H’ is significantly lower then one can conclude that this area is under pressure from something. If the area is within close proximity to intensive industrial activities, action must be taken by the authorities to ease the pressure off this region of the coral reef. This is where Anti-Industrial Green Areas can be established.                                                                                                                       In forests that are at risk of being annihilated, governments have imposed Green Areas that prohibits cutting down of trees and development near there. A similar method can also be applied the Great Barrier Reef. “Anti-Industrial” means void of all industrial activities including factories, “Green Area” mean an area of the coral reef that have been studied using Quadrant analysis and if they are at risk (i.e. the H’ value is very low) then any industrial activities within a certain distance from it must be ceased and proper preparations must be put in place to relocate these factories and development projects.



            This particular management strategy can be considered as a more active method of preserving coral reefs and should be considered as a secondary resort and should only be implemented if the damage is critical and the species richness is at a borderline level. In other words, using this management strategy  would prove useless in a situation where the reef has been subjected to a huge influx of oil; imposing green areas would do nothing because the oil would still be there. One of the cons of this would be that draining a certain region of the ocean is near impossible because unlike freshwater biomes like ponds, the coral reef ecosystem, though it is a separate biome is interconnected with the entire marine environment and also the cost of such a project would take an enormous amount of capital that will have to be allocated individually from the annual budget.                                                                                                                                                 The way in which Systematic Draining and Replenishment (SDR) would work is that special filters can be installed at several high risk areas of the coral reef; these are filters that are powered by marine vessels that will be anchored near the reef and will be monitoring the progress of the filters. It is not a case of replacing “contaminated” water with “new” water like in an aquarium but rather the water is constantly moving through these filters and the denser liquid which is usually oil will be trapped during circulation and the less dense water will continue to move through. Depending on the extent of the contamination, this filtration-type method will take months-years to be complete. Under critical circumstances both management strategy I and II can be combined so during filtration, all the anti-industrial green area laws should be in effect and vigorously enforced. This is a sustainable strategy to use because it incorporates modern technology which can be improved as computer technology becomes more sophisticated. With the appropriate funding by the Australian government, systematic draining and replenishment can technologically solve the problem of industrial pollution without causing a long term economic crisis.


            The runoff of sediments and nutrients from upland areas pose an enormous threat to the Great Barrier Reef because it directly affects the ecological balance of the reef. Nutrient runoff is common when the waterways are close to farms that use artificial inorganic fertilizers that may seep into the ground water and runoff into nearby freshwater areas which eventually empty out into marine environments. When the fertilizers have reached the coral reefs, this is where the danger begins.

            It is well known that nutrients are necessary for the growth of algae and this in turns nourishes primary, secondary, and quaternary consumers. More importantly algae may form symbiotic relationships with corals; in fact these relationships are so important that survival of corals is contingent upon this symbiosis. Hence, nutrients is essential, however when an excess of nutrients is deposited, there is an overgrowth of macroalgae. When the coral population declines and macroalgae composition undergoes a rapid increase, a “phase change” has said to occur (McCook 1999). Phase changes can be considered as an effect that is opposite to that of industrial pollution. While factory pollutants can prevent photosynthetic activity by clouding the shallows, nutrient runoff rapidly increases macroalgae population which may increase photosynthesis but can completely tip the balance of the mutualistic relationship between the algae and the coral causing harm to the coral and ultimately destroying it.

            A management strategy that can be implemented in this situation must first take into consideration the delicate ecological relationships that exist within the coral reefs. Macroalgae are necessary for both corals and fishes that live there. A shift in the ecological pyramid may cause immense and even irreversible damage to the biome if not restored in a short period of time. Nutrient runoff can cause an excess build-up of nutrients and hence a gargantuan rise in macroalgae population. This can overpopulate an area and “drown” out the corals causing a phase change whereby coral growth is halted and macroalgae growth continues to increase. The effect of this on the ecological balance of the coral reef is as follows:

  (image taken from

     CORAL REEFS (Phase changes occurs when producers overpopulates corals)

The ecological pyramid here is disturbed when there is an increase in producers. Basic ecology will say that an increase in the bottom means more prosperity for the entire ecosystem however in the coral reef ecosystem; a huge increase would be detrimental to the corals.




            Unlike the strategies used to deal with industrial pollution, a more natural strategy to control nutrient pollution can be proposed. This biological strategy can be implemented in order to address the problem of phase change. Even though an increase in algae would result in an increase in herbivorous species, the herbivore population will still be kept in check by organisms at the higher trophic levels which will also experience an increase in their numbers. Hence by introducing new herbivores into the coral reefs, the algal blooms can be reduced, however, like most ecosystem management strategies that involved introducing a new organism, its life story must be well understood including its reproductive rate, potential predators, food and physical conditions necessary to keep the organism alive and also to keep it at numbers that would allow it to adapt to the ecosystem. In other words sustainability plays a big role in terms of introducing a new species into an area.

            The easiest way to implement this strategy is to stay clear of exotic species that may prove invasive to the Great Barrier Reef. By doing this, one eliminates the possibility of causing a severe disturbance to the reef’s ecological balance. Instead, it is more recommended that a suitable herbivorous species that can be introduced is one from an area that is least affected by the nutrient runoff. As mentioned in the introduction, the Great Barrier Reef is the largest coral reef in the world. Hence by choosing a herbivore further out from the area of intense disturbance, one can use aquaculture methods to increase its population and then release this into the area of the reef with the algal blooms. The effect can be qualitatively monitored on a day by day basis and if the intended effect is occurring then it can be monitored on a week by week basis and then a month by month basis and so on until the species become established and the coral population returns. Of course this strategy by itself cannot create a sustainable reef; the authorities must also be involved in regulating farmers and the type of fertilizers and chemicals that they use especially if the farms are located near waterways that eventually deposit into the ocean where the reefs are located.

  POTENTIAL LIMITS OF PROPOSED MANAGEMENT STRATEGIES Management Strategy I (concerning industrial pollution)

            While quadrant analysis is a satisfactory method of having a comprehensive idea of the state of the reef, realistically, though such a technique has a high probability of being successful, one must keep in mind that the coral reef ecosystem like any other ecosystem involves a dynamic interplay between producers and consumers and the effect of changes in climate (global warming which was not factored into this report) and human induced effects. Therefore to ensure that a complete analysis is done, each quadrant has to be analyzed several times. This would take a large chunk of the government’s budget to carry out such extensive research on the reef and as seen through the years, many nations are more willing to dedicate their wealth to other purposes besides environmental issues. Hence, for this strategy to really be effective the government needs to play an active role in securing funds and also actively enforce the anti-industrial Green Area laws that are made after the threat is confirmed by quadrant analysis.

Management Strategy II (concerning industrial pollution)

            Once again, the effectiveness of SDR all depends on how well such a management technique will be funded. If proper funds are allocated for investment in the technology then this strategy will be a huge success in terms of improving water quality of the Great Barrier Reef and hence protecting the corals.

Management Strategy III (concerning nutrient pollution)

            The limit to this strategy would be the problem of establishment of the introduced herbivore. Even though the herbivore may be native to the Great Barrier Reef, the fact is that there is a chance that the species may not be able to survive in the region of the reef where it has been transplanted mainly because aquaculture tends to produce species that can disturb and reduce the genetic diversity of the species for example, when aquaculture species escape and breed with the native species.. The other problem would be that the herbivore would not be selected as a prey by the secondary consumers or other animals at the higher trophic levels so it may undergo a population burst. This would result in competition with the original herbivores from that area and the algae population may not only begin to decrease but it may decrease to the point where it becomes a problem.


            After evaluating the threats of the corals and also the strategies which can be implemented to restore these reefs to their original condition, one can see how important it is for such issues to be addressed by the government and be available to the public. Of course as previously mentioned these strategies may be sustainable but they require considerable amount of capital which has to be allocated by the proper authorities. These management strategies listed are key to creating a sustainable path that would allow the Great Barrier Reef to continue existing within the parameters of nature and not be disturbed severely by human related effects. Corals have provided living things including humans with a vast source of food and beauty, and in this world of technological advancements, the Great Barrier Reef is one of the few living wonders of the world that is being threatened by these advancements. In conclusion, preserving the Australian reef will not only serve purpose there but the Great Barrier Reef can also act as model that can be further applied to the rest of the world.




Annual Review of Ecology, Evolution & Systematics….Volume 34, 2003---Futuyma, Shaffer, Simberloff pp. 661-669


At Issue: Are the World’s Coral Reefs Threatened….Thomson Gale 2005----Charlene Ferguson


RESEARCH ARTICLE: Macroalgae, nutrients and phase shifts on coral reefs: Scientific issues and management consequences for the Great Barrier Reef…..L.J McCook …..Published 13th August 1999.


REPORT ARTICLE: Impacts of Terrestrial Run-off on the Great Barrier Reef World Heritage Area….David McB Williams, CRC Reef Research Center, Australian Institute of Marine Science…..Published August 2001


Principle Water Quality Influences on Great Barrier Reef Ecosystem….Great Barrier Reef Marine Park Authority 2006


Biology: Seventh Edition……Campbell and Reece 2005


ARTICLE: Organochlorine, Heavy Metal and Polyaromatic Hydrocarbon pollutant concentrations in the Great Barrier Reef Environment: A review….David Haynes, Johanna E Johnson….Great Barrier Reef Marine Park Authority 2000