Featuring C-DEBI researchers John Spear and James Bradley.

Orange, tree-like cone structures up to two centimeters tall found in a California hot spring were built by a rich and diverse community of microbes, newly published research shows.

These microbes, living in a California hot spring aptly named “Cone Pool” by researchers in the Long Valley Caldera, just east of Mammoth Mountain in California, built sturdy Christmas tree-like structures using calcium carbonate—the same mineral used by corals to form their skeletons.

John Spear, professor of civil and environmental engineering at Colorado School of Mines, was part of the international team of researchers working on the project. Their findings were published Nov. 21 in the journal npj Biofilms and Microbiomes.