Australia, 22 February 2007 – Pesticide-rich plumes of sediment spewed out of Australian river mouths have been shown to reach the Great Barrier Reef, threatening to damage the coral and other sealife which make up the natural wonder.
Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) has published satellite images which showe that the commonly-held belief that river waters would disperse before reaching the reef was not always true.
While under normal circumstances the force of the flow leaving estuaries is insufficient to carry sediment more than 15km out to sea, in extreme conditions the polluted waters can hit both the inner and outer reefs while sediment is still at high concentrations.
The plumes are the result of heavy rainfalls in northern Queensland in late January and early February 2007 following a long dry season. The resulting flood waters carrying a larger sediment load than during regular rainfall and river flow.
Low rainfall preceding the increased flow means that potentially harmful pollutants such as pesticides, herbicides and fertilisers have had time to accumulate, having a significant impact on the marine ecology of the reef.
The CSIRO used images from NASA satellites to build up a picture of what was happening during these extreme events which may have gone unnoticed above the surface but could have lasting consequences for coastal waters.
According to the organisation’s Arnold Dekker, extreme coastal events have been captured by remote sensing before, this is the first time they can be seen and analysed straight after the event as there are now more satellites imaging the Earth and CSIRO has invested in fast information delivery systems. “A re-think is needed now that we know where flood plumes go and what this means as organic micropollutants may be travelling to parts of the reef scientists hadn’t thought to look before.”
– About ‘The Great Barrier Reef’
The Great Barrier Reef is the world’s largest coral reef system, composed of roughly 3,000 individual reefs and 900 islands, that stretch for 2,600 km covering an area of approximately 344,400 sq. km. The reef is located in the Coral Sea, off the coast of Queensland in northeast Australia. A large part of the reef is protected by the Great Barrier Reef Marine Park.
The Great Barrier Reef can be seen from outer space and is sometimes referred to as the single largest organism in the world. In reality, it is made up of many millions of tiny organisms, known as coral polyps. The Great Barrier Reef was also selected as a World Heritage Site in 1981. The Queensland National Trust has named it a state icon of Queensland.