While money may not grow on trees, gold certainly does, according Aussie researchers. A new study reveals that the roots of eucalyptus trees have the ability to draw up tiny gold particles from deep within the soil, and the gold eventually collects in the leaves and branches.
Although it would hardly be worth the effort to harvest the trace amounts of gold from the trees, the more important finding is that the precious metal in the leaves is a certain indicator of the presence of valuable gold deposits 100 feet or more below the surface.
"If you had 500 eucalyptus trees growing over a gold deposit, they would only [yield] enough gold… to make a wedding ring,’’ said geochemist Mel Lintern, who headed up the research on behalf of the Commonwealth Scientific and Industrial Research Organization.
"There might be tons of gold underneath and yet the amount of gold in the tree is very small.’’
Lintern contends that analyzing the gold content of trees in Australia — or anywhere else in the world — is a far more efficient, cost-effective and eco-friendly way of testing areas for potential gold exploration. Mining companies usually drill test holes to locate gold ore deposits, and a single exploratory drill hole could cost tens of thousands of dollars.
Because the gold particles are about one-fifth the diameter of a human hair, the Australian scientists had to use a synchrotron, a vast room-sized machine that uses X-rays to map the various elements present in a sample.
The same equipment also can be used to test for other elements, such as platinum, zinc and copper.
"As far as we know, this is the first time that anyone has seen gold in any biological tissue and it just happens to be a eucalyptus leaf,’’ Lintern said.
Gold is toxic to plants, which may explain why the eucalyptus trees moved much of the gold they absorbed from the ground to their leaves, said Lintern. Via this process, the trees can easily shed the gold deposits.
The results of Lintern’s research were published last week in the journal Nature Communications.