Cryoconite holes are a water filled cylindrical melt-holes on glacial ice surface.
It has been reported from glaciers in many parts of the world: Arctic, Antarctic, Greenland, Canada, Tibet, and Himalayas.
(Willem and Els 1994, Wharton et al.1981, Wharton et al. 1985, Gribbon 1979, Kohshima 1989, Kohshima 1987b).
At bottom of the cryoconite holes, dark colored material called cryoconite is deposited.
As the cryoconite absorbs solar radiation and promotes melting of the ice beneath it, the cylindrical holes are formed (see above).
Cryoconite holes have been suggested to play important roles in the glacier ecosystems because many kinds of living organisms have been reported from this structure on the glaciers, for example, algae,rotifer, tardigrada, insects and ice worm. Wharton et al. (1985) suggested that cryoconite holes are individual ecosystems with distinct boundaries, energy flow, and nutrient cycling. Cryoconite holes of Himalayan glaciers were also reported to provide semi-stagnant aquatic habitats to various organisms on the glacier such as algae, insects and copepods (Kohshima 1987b, Yoshimura 1997). Thus, it is important to know the basic characteristics of Himalayan cryoconite holes, such as morphology, distribution, and stability, to understand the glacier ecosystem of this region.