Gold growing on trees? The amazing discovery that surprised scientists

Researchers in Finland have discovered microscopic gold particles in the needles of spruce trees growing above an underground deposit. Bacteria in the tree tissue convert dissolved metal ions into solid particles. The gold is too scarce for commercial mining, but the discovery could help locate deposits through leaf sampling.

Researchers in Finland have discovered gold nanoparticles embedded within bacterial membranes in the needles of Norwegian spruce trees growing above the Iso-Kutko gold deposit in the northern part of the country. The study, conducted by the University of Oulu and the Geological Survey of Finland, found that bacteria residing within the tree tissues may convert dissolved metal ions drawn from groundwater into solid particles through a process of biomineralization. The researchers collected 138 needles from 23 trees and, using electron microscopy and genetic sequencing, identified gold particles in four of the trees (17.4%). The particles are about a millionth of a millimeter in size and are too small for direct commercial mining from the trees. However, the discovery could aid geology in mineral exploration through simple leaf sampling. The headline uses sensational language ('the amazing discovery'), but the body presents a well-founded scientific study.