Evidence for Biological Shaping of Hair Ice

The study investigated the phenomenon of hair ice, which forms on dead wood of broad-leaf trees at temperatures slightly below 0 °C. It was found that the biological activity of a winter-active fungus, particularly Exidiopsis effusa, was necessary for hair ice formation. The presence of this fungus shaped the ice hairs and prevented their recrystallization. Heat and fungicide treatments suppressed hair ice formation, supporting the fungus hypothesis. Chemical analyses revealed a complex mixture of organic compounds, with decomposed lignin as a main component. The study concluded that while the fungus did not affect the freezing rate, it played a crucial role in shaping hair ice, and further research was needed to understand the role of organic matter in this process.