Red dust storm dumped 3m tonnes of soil in Tasman

A dust storm that blew across the Australian coast last month and swept towards New Zealand dumped three million tonnes of soil into the sea between the two countries, researchers say.

At one point, an average of 75,000 tonnes of dust was being dumped each hour into the Tasman Sea.

Strong winds kicked up on September 22 in far west New South Wales, and Sydney residents woke up the following morning to an orange "fog".

The winds pushed the dust into southern Queensland and out across the Tasman Sea towards New Zealand.

Measurements from the Sydney Institute of Marine Science (SIMS) showed the amount of phytoplankton in Sydney Harbour and 10km offshore tripled.

Phytoplankton which use the nutrients - such as nitrogen and phosphates, and trace elements such as iron - contained in the dusty soil are responsible for half of all the plant production of oxygen on the planet.

The researchers said the extra phytoplankton in the Tasman Sea have captured eight million tonnes of atmospheric carbon dioxide to fuel their growth - equivalent to a year's emissions from a coal-fired power station.

The phytoplankton will also work its way through the ocean food chain and produce more fish, the researchers said.

- NZPA