Great Barrier Reef faces pesticide threat
Pesticide run-offs may be polluting larger areas of the Great Barrier Reef than originally thought.
A series of satellite images obtained by CSIRO scientists have confirmed for the first time that sediment plumes travel to the outer Barrier Reef, and beyond.
It was originally thought that the plumes, which can contain pesticides, herbicides and other micropollutants from our river systems, affected only the inner Great Barrier Reef Lagoon and the inner reef corals.
However the new images, taken by NASA's MODIS satellite by GeoScience Australia's Alice Springs site between February 9-13, show they are travelling up to 135km offshore.
The images were taken during the heavy rains in far north Queensland, and show floodwaters carrying a larger sediment load than during regular rainfall and river flow.
CSIRO scientist Arnold Dekker said the images would change the way scientists analysed reef pollution and that they showed landcare practices needed to be improved in order to save the reef from destruction.
"This is the first time it's been really proven that this is a phenomenon that we need to start incorporating into our studies of how we manage the land and what flows from the land, and how it affects the Great Barrier Reef," he said.
"It's a good example of nature being a bit more complex than we think (and) we have to start studying how often these sediments and contaminants reach the outer reefs."
Recent studies have shown agricultural chemicals are so poisonous to coral that it can prevent spawning, even when only present in minuscule amounts.
This was found to consequently hinder the reef's ability to regenerate and protect itself.
The Great Barrier Reef Marine Park Authority is currently overseeing the implementation of the 10-year, $40 million Great Barrier Reef Water Quality Protection Plan to improve land management practices in the catchment area.
It's a plan that Dr Dekker believes should be supported by farmers, tourism authorities and the government.
"It's a no-brainer to say that if farmers are helped to farm as smart as possible, using as little fertilisers, herbicides and pesticides as possible, and only using what the vegetation will take up, then you will have much less run-off of this material," he said.
He said revegetating areas around waterways would help catch the sediments before they reached the ocean
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