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 El Nino may spur toxic algal blooms in Australia
A warning that the current El Nino event may unleash a plague of toxic algal blooms in Australia's rivers and drinking water reservoirs has been issued by the nation's senior land and water scientist. Professor Graham Harris, Chief of CSIRO Land and Water, says there is clear evidence that El Nino events have a "quite disastrous" impact on water quality. "For example, we have twenty-five years of data from North Pine Dam, near Brisbane, which shows a very clear relationship between El Nino events and increased blooms of toxic blue-green algae. "What happens is, we get less rainfall and we're extracting a lot of water from the rivers and the dams anyway. Once the flow slows down, it has now been shown very clearly to favor the growth of these toxic blue-green algal blooms." Blooms of a subtropical toxic algae, Cylindrospermopsis, in North Pine Dam had been found by Australian, Israeli and American scientists to coincide exactly with recent El Nino events over a 25-year period. On a much larger scale, Professor Harris said that the 1992/3 drought provided clear evidence of the link between climatic phenomena and algal blooms. "If you look at a map showing the outbreaks of those blooms in 1992/3, they extend right across the southeast corner of this continent, from a line stretching from Adelaide across to Brisbane. "So if we do see much reduced summer rainfall, then we will start to see outbreaks of these toxic algal blooms through the summer." Fortunately, scientific understanding of the causes of the blooms has advanced greatly in the past five years, due to a combined national research effort by CSIRO, the Murray-Darling Basin Commission, the Co-operative Research Center for Freshwater Ecology and the Land and Water Research and Development Corporation. This led to the recent release of a report, Managing Australia's Algal Blooms, which outlines a strategy for water and land managers to combat the menace. Control strategies designed to minimize the risks to human health include:
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