Scientists in Finnish Lapland have found gold forming inside Norway spruce needles, and the work is being done by bacteria, of all things. These microbes live within the needles and convert dissolved gold from the soil into solid nanoparticles, tiny flecks far too small to see or harvest, but rich in information about what lies underground.⁠ ⁠ Working near the Kittilä gold mine, researchers sampled 138 needles from 23 spruces and detected gold in four trees. Under the microscope, the particles sat inside bacterial biofilms. DNA sequencing pointed to specific groups, P3OB-42, Cutibacterium, and Corynebacterium, that were more abundant in gold-bearing needles.⁠ ⁠ The process is called biomineralization. Water moves soluble gold ions from the soil into the plant, and endophytic microbes precipitate those ions back into solid form, likely reducing the metal’s toxicity for both tree and microbe. The result is nanoscale “gold dust,” measured in millionths of a millimeter, that functions as a...