Outback's loss is Sydney's gain

30 September 2009

When Sydney University's resident dust expert Dr Stephen Cattle awoke last Wednesday, the biggest day of his career had blown into town. "I woke up at 5.30am. When I went outside I thought: Fantastic!" he said. "I knew it was dust as soon as I saw it. It smelt like earth and I could feel it when I breathed. "I realised it wasn't good for farmers and for people with respiratory problems. But, from a scientific point of view, it was very exciting." For the past 10 years, Dr Cattle has been researching the impact of dust on soil formation, collecting hundreds of samples. He described last week's dust storm, which originated in the Lake Eyre region and far western NSW, as a once-in-a-lifetime event.

"It gives us an opportunity to study the knock-on effects of dust storms and the impact on ecosystems, which may be positive or negative," he said. Dr Cattle, a senior lecturer in soil science, immediately set up three dust traps - medium-sized steel pans filled with small marbles - on the roofs of three university buildings. "The dust that blew in on Wednesday was a combination of inorganic dust particles - the red stuff - plus organic matter," he said. "When that organic matter decomposes, it provides the soil with nutrients like nitrogen and phosphorous. "So, when you have a big wind event like we had, you lose a lot of the organic matter which helps build soil structure." Dr Cattle said the loss of so much topsoil would have damaged the fertility of the land it came from, reducing its capacity for pasture. "But the inland's loss is Sydney's gain, with those nutrients landing in our back yards," he said. As well as nutrients, Wednesday's red clouds included seed particles from annual grasses. Are Sydney gardeners in for an extra-busy summer of weeding? It's a possibility," Dr Cattle said. "The particles that came to Sydney were between 18 and 20 micrometres, which is smaller than a hair."

Contact: Dr Stephen Cattle

Phone: 02 9351 2944

Email: 0a1a09101d250d2c264d15100b61571527650c37