Mind the Koalas: "Gold Particles in Eucalyptus Trees Can Reveal Deposits Deep Underground"

From Smithsonian Magazine's Surprising Science blog:

New research shows that eucalyptus trees can absorb gold particles in their roots and transport them up to their leaves, a finding that could be a boon for mining companies. Photo by Mel Lintern

If you traveled to the town of Kalgoorlie, in Western Australia, then headed about 25 miles north, you’d eventually reach a grove of large eucalyptus trees, some more than 30 feet tall, scattered across a dusty, arid landscape. Examining the dirt at your feet would reveal no trace of the gold deposits that lie roughly 100 feet underground, due to the thick layers of clay and rock that sit atop the precious metal.

But, scientists recently learned, if you peered closely enough at the eucalyptus trees—specifically, using X-rays to detect nanoparticles—you’d find that there’s gold in them thar leaves. As detailed in a study published today in Nature Communications, a group of researchers from Australia’s Commonwealth Scientific and Industrial Research Organisation has shown that plants can absorb gold particles deep underground and bring it upward through their tissues—a finding that could help mineral exploration companies  mine for gold.

“In Australia, we’re faced with this problem of trying to explore through thick layers of sediments and weathered rock to reach valued minerals,” says Melvyn Lintern, an Earth scientist and lead author of the study. “At the same time, we’d previously heard from mining engineers that, in some places, they’d found eucalyptus roots going down to 30 meters [98 feet] or deeper in the mines.” With this observation in mind, and the knowledge that plants can absorb and transport minerals from the surrounding soil and bedrock all the way up to their leaves, Lintern and his colleagues were struck with an idea: Why not test eucalyptus leaves to see if they could indicate underground gold deposits?...MORE