Scientist discovers Midas touch - www.smh.com.au

Scientist discovers Midas touch - www.smh.com.au: "Gold nuggets may really be the work of bacteria that can grow the precious metal in much the same that way marine organisms build coral reefs.

That is the theory of a Canberra scientist who has detected DNA bonded to tiny gold flakes.

Frank Reith, a geo-ecologist and doctoral researcher at the Co-operative Research Centre for Landscape Environments and Mineral Exploration, also has evidence that tiny organisms can dissolve gold from soil.

Mr Reith discovered that strange formations on the surface of gold flakes were covered in a thin film.

Tests revealed the film contained DNA, confirming that it was the result of bacterial action.

'We have seen biofilms growing on the gold flakes,' he explained yesterday. 'Cells were bound to the gold.'

It had long been suspected that many organisms, including plants, could dissolve microscopic particles of gold from soil and rock.

To test this hypothesis, Mr Reith placed samples of soil collected from a NSW gold mine in water and added miniscule amounts of the metal. Subsequent tests revealed the water contained up to three parts per million of dissolved gold.

But when the experiment was repeated using soil that had been sterilised against bacteria and fungi, there was 'little or no dissolved gold'."