Woman teaching childrenFormer MCM PhD student Anna Bergstrom, pictured here at an Antarctic Family Day event, studies Cryoconite holes in the Dry Valleys.

Cryoconite holes are holes in a glacier's surface caused when dirt (also called sediment) is carried by wind onto the glacier. Because the dirt is darker than the ice, it warms up in the sun and over time, it melts into the glacier. We demonstrate this phenomenon using two blocks of ice from the grocery store, in a clear tote, with heat lamps arranged at the same distance and angle. We invite members of the public to add sprinkles or pinches of dark sand to the top of one of the ice blocks and observe what happens over time. This demonstration works well for demonstrating the impact of "dirty snow" on snowfields as well. 

Why are cryoconite holes important? They are self-contained ecosystems that include the abundant bacterial life that arrives clinging to the sediment and then nourished by liquid water. They have recently gained the attention of microbial ecologists looking to use cryoconite holes as “natural microcosms” to study microbial community assembly. Scientists in the Schmidt lab at CU Boulder have been examining the idea that cryoconite holes are like islands: in the same sense that an island in the ocean is an area of habitat isolated from other islands and the mainland by an ocean, in the case of cryoconite holes, the "ocean" is comprised of impermeable solid ice. 

They're also important because they change the surface of the glacier, potentially impacting run-off and how nutrients move through glaciated landscapes. 

What is a Cryoconite Hole? https://youtu.be/JzVbcOwopS4

Learn more about these fascinating microhabitats on glaciers and how Antarctic researchers are studying them with a former graduate student and postdoc asociated with the MCM LTER, Pacifica Sommers. https://youtu.be/nWXYqJuAyIQ