Delicate strands of extraordinarily thin ice grow out of rotting tree branches like hairs on a head. The ephemeral hair ice can last for only a few hours to a few days if the temperature stays freezing. Researchers have known that cold-tolerant fungi are responsible for the tufts of ice, but only recently uncovered the species responsible for the ice growth, the chemical composition of the melted hair ice and how the fungi stimulate the unique ice growth. All photos were taken by the researchers, including Gisela Preuß, a biologist at the Wiedtal-Gymnasium in Neustadt, Germany, and Christian Mätzler, a co-author of the published study and professor emeritus at the Institute of Applied Physics at the University of Bern in Switzerland. [Read the full story on hair ice]

Melting hair ice

Close-up of melting hair ice. Credit: Hofmann et al., Biogeosciences, 2015. [Watch Hair Ice Grow in Time-Lapse Video]

Hair ice on the forest floor

Hair ice discovered on the forest floor near Brachbach, Germany. Credit: Gisela Preuß.

Hair ice sprouting

Hair ice sprouting from a branch. Credit: Gisela Preuß.

Hair ice basking

Hair ice in forest near Moosseedorf, Switzerland. Credit: Christian Mätzler.

Hair ice in the forest

Hair ice on the forest floor in Brachbach, Germany. Credit: Gisela Preuß.

Hair ice drooping

Hair ice growing on a branch in Moosseedorf, Switzerland. Credit: Christian Mätzler.

Hair ice from below

Another view of hair ice growing on a branch near Moosseedorf, Switzerland. Credit: Christian Mätzler.

Hair ice in a cocoon

Hair ice growing into a cocoon shape on a branch in Moosseedorf, Switzerland. Credit: Christian Mätzler.

Hair ice in coifs

Coifs of hair ice growing on a branch in Moosseedorf, Switzerland. Credit: Christian Mätzler.

Hair ice in tufts

Tuft of hair ice on the forest floor in Brachbach, Germany. Credit: Gisela Preuß.

Hair ice fluffs

Fluffy hair ice on the forest floor in Brachbach, Germany. Credit: Gisela Preuß.