If you think humans are the only ones that like a little bling, you are in for a surprise. Australian scientists have discovered a new pink and fluffy fungus that adorns its long, thread-like tendrils with tiny flecks of gold collected from the soil. The experts hope the "gold-digger" will provide them with clues on the locations of gold deposits and make prospecting for the precious metal easier, and more environmentally friendly.
The gold-encrusted Fusarium oxsporum was discovered accidentally by a team of researchers led by Dr. Tsing Bohu, a geomicrobiologist at Australia's national science agency, CSIRO, when they were examining the microbes in the soil at Boddington. Located about 75 miles (120 kilometers) southeast of Western Australia's capital Perth, the tiny town of about 2,000 residents is home to the country's largest gold mine.
A closer analysis revealed that the organism uses a series of chemical interactions with underground minerals to accumulate gold from its surroundings. The fungi begin by oxidizing the gold, which is often buried in the soil hundreds of feet below the surface. The process causes the metal to lose electrons and makes it soluble in the groundwater, which helps bring the metal closer to the surface. The fungi then use another chemical reaction to extract the dissolved metal and transform it into minuscule particles of gold that cling to their tendrils. "We observed the precipitation of gold on the surface of the fungus," Dr. Bohu said.
Though fungi often interact with other elements of nature, the reaction with gold was not something the researchers would have expected. "Fungi are well-known for playing an essential role in the degradation and recycling of organic material, such as leaves and bark, as well as for the cycling of other metals, including aluminum, iron, manganese, and calcium,” Dr. Bohu explained in a CSIRO press release. "But gold is so chemically inactive that this interaction is both unusual and surprising—it had to be seen to be believed."
While the flecks of metal certainly look stunning on the fungi's tendrils, the organisms are not wearing the gold for vanity. “There is an underlying biological benefit from this reaction,” Dr. Bohu told the Australian Broadcasting Corporation. “We found gold-loving fungi can grow faster and bigger relative to other fungi that don’t work with gold.”
The researchers, who published their findings in the journal Nature Communications on May 23, 2019, still need to conduct further analysis to understand the relationship between the fungi and the precious metal. More importantly, they need to determine if its presence is a sure sign of the existence of large deposits of the metal underground. Study co-author and CSIRO chief research scientist Dr. Ravi Anand says, "The industry is actively using innovative exploration sampling techniques, such as gum leaves and termite mounds, which can store tiny traces of gold and can be linked to bigger deposits below the surface. We want to understand if the fungi we studied, known as Fusarium oxsporum – and their functional genes – can be used in combination with these exploration tools to help the industry to target prospective areas in a way that's less impactful and more cost-effective than drilling." The scientists also believe the fungi could be used to detect the presence of gold in waste products and manmade electronics.
However, those hoping to extract free gold from the fungi are in for a disappointment. For though the Fusarium oxsporum is ubiquitous in soils worldwide, the delicate fungus, which sports pink mycelium, or "flowers," is hard to see. Also, its gold haul, which measures just three or so nanometers wide, is only visible under a microscope.
Resources: Thescientist.com, livscience.com, theguardian.com, smithsonianmag.com