Ecosystems at Risk - the Great Barrier Reef

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Introduction

Charles Darwin, an evolutionary scientists/naturalist, discovered the theory of evolution; in particular, survival of the fittest. This concept can be applied to the modern world and its ecosystems at risk. The human population is regarded as the ‘fittest’; however those ecosystems at risk are at the opposite end of the chain. The Great Barrier Reef is an ecosystem at risk. Climate change, overfishing and increased tourism are threats to the reef both past and present. But what threats lie in the future? With an increasing population, spikes in oil demand and rising carbon dioxide (CO2) levels; extreme strain is being put on the organisms inhabiting the reef. Charles Darwin was the engine room behind the theory of ‘survival of the fittest’; but what if the fittest were to help those at risk?

The Great Barrier Reef

The Great Barrier Reef is a not only a vast, complex community of corals, but a natural wonder in itself. Distinct from any other ecosystem, the biodiversity sampled on the reef is like no other ecosystem in the whole world. According to marine biologist Robin Aiello, “There are more different species of animals and plants in a cubic meter of the Great Barrier Reef, than in any other environment in the world, including tropical rainforests.” This extreme biodiversity is the reason The Great Barrier Reef was heritage listed on the UNESCO (United Nations Educational, Scientific and Cultural Organisation) World Heritage list back in 1981.

        The biodiversity on the reef is triggered by the enormity of symbiotic relationships the reef samples. For Example:

  • The ‘Pontoniine’ Shrimp will position itself at a prominent outpost on the reef where fish will queue up to be cleaned. The shrimp will remove all mucus and parasites from the fish. The fish get cleaned and the shrimp gets a free feed.
  • The ‘Picasso’ Triggerfish will protect corals and sponges from predators such as the ‘Crown-Of-Thorns’ Starfish by tearing off one of the starfish’s arms, flipping the starfish on its back and eating it. For the protection, the corals and sponges will hide the triggerfish when its predators are near.

With the reefs dynamic rate of change, it is no surprise that the total area covered by the reef is approximately 348,000 km2. Stretching from Papua New Guinea’s Fly River (8°N) down south to Fraser Island (24°S) (see Figure 1.1 below), there is an approximated 14,500 species living on the Great Barrier Reef (as of 2008). Changes in water temperature, changes in water currents and changes in weather conditions could devastate the reef and puts its 14,500 species on the brink of extinction. These three, previously listed consequences are repercussions of human induced climate change.

Human Induced Climate Change

Climate change, as defined by Wikipedia, is “a significant and lasting change in the statistical distribution of  patterns over  ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average.” The Greenhouse Effect’s (see figure 1.2 below) effect is furthered by the use of fossil fuel powered technology. The greenhouse gasses emitted by such technology EG Vehicles; are trapped in the atmosphere. Infrared radiation is emitted from the sun and passed through to out atmosphere, warming Earth up. The infrared radiation is then absorbed by the carbon dioxide which in turn, re-radiates the heat causing Earth to warm slightly. This will also heat up the oceans causing higher sea temperatures, changing ocean currents and changing weather conditions. This has significant repercussions on the Great Barrier Reef.

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Higher Sea Temperatures

The Great Barrier Reef is a delicate and sensitive ecosystem which will respond negatively to minimal temperature changes. The average temperature range for the Great Barrier Reef is from 22°C to 27°C. A deviation in these temperatures ranging from 1 - 2 °C (see Figure 1.3 below) for a time bracket of 5 – 10 weeks could start a bleaching event on the Great Barrier Reef.

        Coral Bleaching

Coral bleaching is a stress condition within corals that involves the breakdown of the symbiotic relationship consisting between the coral and zooxanthellae. Zooxanthellae are ...

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