We're eating their dust and now they want it back

21:07, Sep 14 2009
dust
BLOWN OVER: Desert dust from Australia blankets the centre of Christchurch yesterday.

The Aussies sent their dust over here and now they want it back.

Not content with filling South Island skies with a reddy-brown veil, Melbourne scientists want to collect the Australian dust from our pristine snowfields and fly it home.

Once the dust is back on Australian shores, they want to analyse it for bacteria and other constituents, which can have implications on the health of coral reefs and rainforests.

The desert dust cast a pall over large parts of the South Island yesterday, masking clouds and landmarks and reducing visibility to less than 10 kilometres in places.

Weather forecasters were bewildered by the polluted atmosphere when contacted, but by yesterday afternoon, with some help from readers on both sides of the Tasman, The Press had solved the hazy mystery.

Gale-force northerly winds blowing across inland parts of Victoria and South Australia on Friday and Saturday appear to have lifted vast amounts of dust from the dried-up Lake Eyre basin.

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From there, the dust blew across Victoria on Saturday and then over parts of Tasmania, where it mixed with falling rain to turn cars and outdoor furniture red on Sunday morning, before arriving in New Zealand late in the day.

Environmental scientists at Monash University in Melbourne contacted The Press yesterday with details of the dust's travels over the weekend and asked for help in getting some of it back.

School of Geography and Environmental Science professor Nigel Tapper said researchers were looking at the microbiological content of Australian dust.

"Some of the bacteria have implications for the ecosystem health of coral reefs, rainforest, etc," he said. "It would be great to sample some of the dust that passed over to you to check biological content; best would be getting some snow-surface samples from the Alps."

Any dust collected from snowfields in the Southern Alps would need to be carefully scraped into sterile containers.

Colleague Tadhg O'Loingsigh, a research fellow, said it was recognised that Australian dust went into New Zealand glaciers and did not just coat the surface of loose snow.

Scraping samples from snow was a clean way of collecting the dust and "it's one place we know it's been trapped and it would still be clean".

The north-west winds that helped carry the dust also pushed temperatures to summer-like levels in Canterbury yesterday.

Timaru reached 27 degrees Celsius and Oamaru 26C in mid-afternoon, but thick high cloud in Christchurch prevented the temperature from rising above 22C.

The Press