Please forgive me if this is sounding really repetitive but I think you should really read this. We have been blessed with a beautiful and wondrous reef which we are killing with pollution.
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The Impact of Pollution:
Sediment, nutrient and pesticide pollution from catchment run-off is also affecting the health and resilience of the reef ecosystem.
The amount of sediment flowing into the marine park has quadrupled over the past 150 years. This increase can largely be blamed on grazing and cropping expansion in the catchment, which has also resulted in the loss of native vegetation and wetlands.
Nutrient loads have also increased, encouraging algae blooms, which, in turn, provide food for larvae of the devastating crown-of-thorns starfish. In addition, nearly one-third of the reef is now exposed to pesticides.
The reef is currently experiencing massive problems with the crown of thorns starfish. The crown of thorns starfish is "a coral eating starfish or sea star native to coral reefs in the Indo-Pacific region". This puts the Great Barrier Reef at risk because if these starfish become too abundant, they will simply eat all of the coral in the reef. "When crown-of-thorn starfish numbers are low, corals can recover from any damage caused by their feeding - maintaining a balanced and healthy environment. At these times, control is not required, as this is a naturally occurring event. However, when the crown-of-thorns starfish population increases to a point where the coral can no longer recover from the damage caused, there is significant danger to the health of the reef. This is called a crown-of-thorns starfish outbreak." Throughout history, outbreaks of crown-of-thorns starfish have occurred approximately every 80 years or so. In recent years, these outbreaks have increased in frequency until now they are occurring ever 15 years. It is thought that a decline in water quality entering the reef from water ways is to blame.
The Impact of Climate Change: Picture thanks to the Great Barrier Reef Marine Park Authority
The Great Barrier Reef Marine Park Authority’s Outlook Report for the Great Barrier Reef in 2009 stated: “the threats of increasing sea temperature, ocean acidification and rising sea level are assessed as very high risk to the ecosystem... . Their impact will be compounded by each other and by other existing regional and local threats". Increasing sea temperature affects the Great Barrier Reef as it causes coral bleaching. Coral bleaching is when the relationship between the coral and the algae which gives the coral its colour, breaks down. Rising sea level temperatures cause the relationship to break down by causing the coral to bleach. Coral can be very sensitive to changes in sea temperature. For example, a rise of one degree celcius for four weeks can cause some types of coral to bleach. Cases of coral bleaching are set to become more common as sea temperatures rise due to climate change. The Impact of Ships:
One other human impact upon the Great Barrier Reef is the large amount of ships passing through the area annually. As the reef extends down much of the Queensland coast, it consequently has an abundance of maritime traffic constantly passing over it. It is not just when ships have accidents over the reef is it effected. The ships passing over the reef drop debris and other objects foreign to the reef. Additionally, the ships that travel over the Great Barrier Reef have their hulls covered in a substance known as Tributyltin. Tributylin preserves the hull of the ships but is toxic to the reef and can impact the various marine organisms that it comes into contact with. The Great Barrier Reef is under attack from many different fronts, some natural and some man made, but one thing they all have in common is that the reason they are impacting the Great Barrier Reef is because they have been created, or stimulated, by humans.







