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Eucalyptus trees make bank with gold

By SOPHIA GAUTHIER | October 26, 2013

Money doesn’t grow on trees but apparently gold does.

Scientists studying in Western Australia decided to give the ubiquitous eucalyptus tree a closer inspection upon discovering gold particles in their leaves. Although previous research has identified gold flecks in vegetation and sedimentation before, it was unclear where such riches were originating.

According to Melvin Lintern, head of a team of scientists in earth sciences and resource engineering at the Commonwealth Scientific and Industrial Research Organization (CSIRO), there is now definitive evidence that the eucalyptus trees in the Kalgoorlie-Boulder region of Western Australia were syphoning gold particles into their veins from gold deposits dozens of meters underground.

Eucalyptus trees root deep in the ground and can extend 50 meters into the earth where they may happen upon natural mineral deposits. Finger-like roots grope through the earth in search of nutrients and water although they apparently do not discern such resources from others. The eucalyptus trees in the study sit above a literal gold mine, drawing up nuggets of the coveted metal suspended in water. The study suggests that the gold may be harmful to the trees and posits that they attempt to exude the mineral through their leaves where it will be shed to the ground.

This detoxification is rather ironic given that the natural oils secreted by eucalyptus trees are powerful disinfectants that are dangerous to many other organisms in large quantities.

Koalas are one of the few creatures known for regularly feasting on the poisonous plant, since they possess natural resistance to its pernicious effects. Regardless, tiny flecks of gold a little under 10 microns in diameter or one-fifth the diameter of a human hair are discernible within the fiber of such eucalyptus trees.

Although there is not enough gold in the leaves to reap any kind of monetary profit, researchers have found other, arguably more beneficial, uses for the phenomenon.

Eucalyptus trees are fairly prevalent throughout the country and could potentially be growing over other valuable mineral deposits. By analyzing the mineral content of eucalyptus leaves and the topsoil shadowed by them, scientists could potentially identify natural resources hidden deep in the earth in an eco-friendly “non-invasive” manner. Such ideas are further detailed in Lintern’s paper in Nature Communications.

Gold in other organisms is not entirely unheard of.

Your very own body contains trace amounts of the mineral, although there is no biological purpose for its presence. However, if there is about 0.2 mg of gold in the average person, then koalas must be loaded.

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