Thursday, November 8, 2012

Scientists Confirm Human Impact on Destruction of the Great Barrier Reef

The Great Barrier Reef stretches for over 1,600 miles off the coast of Queensland, Australia. It is made up of over 2,900 individual reefs and 900 islands, making it the world's largest coral reef system. However, in recent years, scientists in Australia have linked human development on a nearby island to the collapse of coral in Queensland's Palm Islands. Studies show that a healthy community of Acropora corals thrived for years through floods and cyclones, until its decline in the years 1920-1955 when Europeans began to settle in the area.

The reef's damage resulted from polluted runoff making its way into the Great Barrier Reef lagoon. This lowered water quality includes "suspended sediment, excess nutrients, pesticides, and fluctuations in salinity" caused by humans clearing nearby land for grazing and agriculture. In previous years, corals have been known to die and recover from natural disasters such as floods and cyclones, but the chronic impact of human settlement has reduced the coral's ability for re-growth. Also this, coupled with the effects of climate change (increasing temperatures, storms, and coral bleaching) and "overfishing which disrupts food chains, and shipping routes which can result in oil spills or improper ballast discharge" together create an improper environment for coral growth.
By using uranium dating methods, scientists have confirmed that despite all other natural impacts, corals continued to flourish until recent years when they began to collapse in direct correlation to human involvement. Two sites of Acropora corals have vanished while another site has shifted species from Acropora to Pavona. These studies pose another problem that these shifts may seriously underestimate major shifts in coral populations to come. It remains to be seen whether this pattern will continue to develop or begin to worsen as human involvement persists. 

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