“I’ve spent the last 30 years in every rainforest in the world … looking for antibiotics,” antimycotics, antioxidants and anti-cancer agents, among others, he said.

His detailed attention to plants and fungi are what prompted his discovery in Huanglong. The region is dense with rhododenrons, a woody plant from the heath family with thick leaves. When the leaves drop into the cold water, other fungi present in the water attach themselves to the leaves. When Strobel picked up a leaf from a pool at Huanglong, he noticed filaments hanging off and “knew immediately” they had a role in creating the travertine dams.

His theory was proven by other researchers in the lab — including Jie Xie and her colleagues from Southwest University in Chongqing, and Brad Geary at Brigham Young University in Provo, Utah. As an interesting aside, Jie Xie’s photo on the Southwest University website shows her standing in front of Yellowstone’s Lower Falls.

When the fungi samples were examined under an electron microscope each filament had a crystal growing on it. When the fungi died, the crystals were left behind with a distinct hole in each one where the filament had been attached. Eventually the crystals fuse and build the travertine dams where the leaves pile up in the pools, a process that may date back about 126,000 years.