There’s gold in them thar leaves! Scientists have discovered that eucalypts growing over large but deep gold deposits take up gold with their water, making them an indicator for new underground gold mines.
In Western Australia near the gold town of Kalgoorlie, there’s a stand of eucalypt trees that get their water from roots that extend down about 30 metres through many layers of sediment. The lowest layer is a gold rich seam, and tiny traces of that that dissolved gold has been found in tree leaves. Although minute, the amount does vary enough to show proximity to a likely gold exploration site.
It’s thought that the gold might be translocated all the way to the tree’s leaves in an effort to get rid of it. Gold may be beautiful to us but, as its a heavy metal, it’s toxic to living tissue.
Diagram from Natural gold particles in Eucalyptus leaves and their relevance to exploration for buried gold deposits. Lintern, Anand, Ryan and Paterson. Nature Communications, Article number 2274. doi:10.1038/ncomms3614