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While you may never find money growing on trees, there is a chance that you could strike gold - literally! The best part is that the precious metal bearing trees are not in some far out planet, but right here on earth, in the Australian Outback.
The magical leaves belong to the eucalyptus trees that are abundant in Western Australia, an area known for its vast gold deposits. For many years, researchers debated whether the traces of gold that were sometimes discovered on the leaves, were blown from the atmosphere or drawn up from underground, by the deep-reaching roots of the eucalyptus tree.
To settle the dispute once and for all, a team of researchers led by Melvyn Lintern from the country's national scientific agency CSIRO, compared the leaves of the eucalyptus trees near a known gold prospecting site in Western Australia to those off trees growing about 3,000 feet away. They also conducted an in-house experiment by planting the trees in a greenhouse - some with potting soil that contained particles of gold and others, without.
In each case they discovered that the leaves of most of the trees that were close to the gold deposits contained microscopic particles of the precious metal, while the others did not. This has led the researchers who published their findings in the October edition of Nature Communication, to conclude that the eucalyptus roots which extend tens of meters into the ground, act like hydraulic pumps drawing up water that contains the gold. They speculate that the precious metal is toxic to the plant, which is why it moves it out to its branches and leaves, where it can be tossed out easily. The one thing that the team does need to investigate further, is why despite being close to the deposits, certain trees are able to avoid drawing up the toxic metal.
However, before you start dreaming of participating in the next 'gold rush', keep in mind that the amount of gold is less than 0.000005% of the weight of each leaf or so minuscule that one would have to remove all the leaves from 500 eucalyptus trees, to yield enough for a simple gold band.
So why all the excitement? Because it will allow Australian gold mining companies to prospect for the precious metal more intelligently. This will not only help reduce the cost of discovering the metal, but also the environment, because it reduces unnecessary drilling.
Additionally, given that eucalyptus trees are rampant throughout the country, the same technique can be used to find other metals like copper and zinc, which scientists suspect, the deep roots also draw up. This news is particularly significant for Australia given that it is one of the world's largest producers of gold, second only to China. The country is also a significant producer of zinc and copper.
Resources: nationalgeopgraphic.com, theindipenedent.com, gizmag.com