The Type Of Tree That Can Actually Grow Gold

Life on Earth comes in countless shapes and sizes, but all organisms are overwhelmingly composed of just a handful of common elements. In fact, the three most common elements in the human body are carbon, hydrogen, and oxygen, which together account for over 93% of all mass in the body. Other elements, such as calcium and iron, are also used for biological processes, albeit in comparatively small amounts; that's true in humans, as well as in most other living things. That's why when scientists discovered trace amounts of gold in the needles of Norway spruce trees, exactly how the precious metal got there in a solid state was a mystery.

Now, researchers have pinpointed the most likely culprit behind the gold-sprinkled needles: bacteria. According to a 2025 study published in the journal Environmental Microbiome, specific taxa of bacteria were found clustered within the needles of the Norway spruces that contained gold nanoparticles. Yet, such clusters were absent in the Norway spruces that didn't contain gold nanoparticles. These findings suggest that, rather than the tree "smelting" gold ions into solid gold on its own, the microbes are the true metalworkers.

Scientists already knew how gold travels from the ground to plant tissues. Gold particles in soil exist as free-floating, individual ions that dissolve in water, so they can easily make their way through a tree's vascular system as it draws up water. From there, the tree may isolate and store metal ions in its tissues to use for essential processes, such as growth and defense. However, the stored gold remains as disconnected, individual ions — at least until certain microbes find them. The researchers identified three specific bacterial taxa that were clustered around solid gold nanoparticles. The team suspects that when these microbes build their shelters, called biofilm, they precipitate gold ions into solid gold in the process.

How exactly the microbes turn gold ions into solid gold is yet unknown, but the latest findings are a step forward for the study of geology, ecology, and environmental management. Geologists have long known that plants accumulate metals from the soil. Indeed, surveyors take advantage of the phenomenon in a practice called "biogeochemical exploration." Rather than drilling into the ground to test rocks for gold and other metal contents, biogeochemical techniques can simply analyze the composition of the plants that grow above the site.

But as useful as the technique may be, it's not very accurate, partly because scientists don't fully understand the biological mechanisms that cause metal ions to mineralize in plants. As researchers learn more about the role of bacteria, biogeochemical analysis techniques can be refined and sharpened. In the future, geologists may be able to rely almost entirely on biogeochemical analyses and leave conventional methods in the past. That would mean less blind drilling and excavation, practices that are often disruptive to local ecosystems.

Biogeochemical science may help in efforts to clean up pollution, as well. The process highlighted in the 2025 Scandinavian study, in which plants absorb metal ions and convert them into solids, is called biomineralization. Researchers are hopeful that biomineralization may be the key to removing heavy metals and other pollutants from contaminated water and soil. Some experts have proposed using biomineralization to remediate abandoned strip mines, where the chemicals used in mining often leaves the exposed earth toxic. To that end, the latest findings suggest that plants can't clean up pollutants alone, though — they need some specific microbes on their team.