Most people have heard of the Great Barrier Reef, even if they don’t know precisely where it is or how vast it is. According to Greatbarrierreef.org, it is so large that it can be seen from outer space and it is the largest reef system in the world. Situated on the north-east coast of Australia, it consists of nearly 3,000 individual reefs, made up of 400 different types of coral, and stretches for over 2,500 kilometres. It is also home to huge amount of wildlife, including 30 different species of dolphins, porpoises and whales, about 1,500 species of fish and over 200 bird species. Endangered species such as the dugong, or sea cow, and the large green turtle, treat the Reef as home.
Unfortunately, the Great Barrier Reef, as well as all the wildlife that live there, is at risk for a number of reasons. In fact, over the last 90 years, the Reef has experienced a number of collapses and, as another study shows, the amount of coral has halved over the last 25 years. Scientists from the Australian Institute of Marine Science in Townsville, Queensland have been able to conduct a type of autopsy on the coral, predominantly from three sites around Pelorus Island, “an inshore reef from the Palm Islands region of the central GBR.” or
The data from their findings showed that, up to the 1920s, the Reef had been more or less pristine, but that once European settlers moved in and started farming the land, it affected the coral to an extent that it virtually killed off the coral in two of the sites investigated and caused the other site to be colonised by different types of coral.
According to the report and related news articles, there are three main reasons for the coral being destroyed:
Run-off from farmed land
Farming, primarily livestock and sugarcane, resulted in a number of the rivers leading to the Reef being infiltrated by herbicides and other substances. The extra nutrients in the water spur on the growth of seaweed, which then slows down the regeneration of the coral.
Crown of thorns starfish
Another study suggests that the poisonous crown of thorns starfish has been responsible for 42% of the damage done to the reef. The female starfish lays around 50 million eggs a year and feeds on coral polyps, which can devastate the coral. Some experts are calling for a cull of the starfish, but as they are poisonous, this is not as easy as it sounds.
Extreme weather conditions
Finally, cyclones and global warming affect the coral in negative ways. Meteorological records show that 27 cyclones passed near Pelorus Island between 1910 and 2010, which will have had a severe impact on the quality of the coral. Global warming is believed to be linked to the bleaching of coral.
The good news is that the coral can recover, if it is given the chance. Unfortunately, it needs 10-20 years to do so and the frequency of cyclones and the impact of global warning are hard to control. However, damage done by starfish and farming can be slowed down, which will hopefully make a major difference.