For the first time ever, researchers have quantified the length and mass of arbuscular mycorrhizal fungal networks globally and mapped the ecosystems where they are densest.By Wyatt MyskowHidden underground around the world lie 110 quadrillion kilometers of arbuscular mycorrhizal fungal networks—webs of ultra-thin threads that, if connected in a single line, would stretch almost a billion times thge distance between the Earth and the sun, according to new research published in Science on Thursday.