Cryoconite Granules: Granular Algal Mats on Glaciers

Cryoconite granules (Yala Glacier, Himalays)
Cryoconite granules are dark-colored spherical algal mats and the main component of cryoconite (biogenic surface dust on glaciers). The granules consist of mineral particles, organic matter, bacteria and cyanobacteria (blue-green algae). Size of the granules are usually from 0.2 - 2.0 mm in diameter. The granules are growing up by cyanobacterial activity. Cryoconite granules are usually depositted at the bottom of cryoconite holes. This granule structure is common on glaciers all over the world.
Cross section of a cryoconite granule shows that the granule include mineral particles and dark colored organic matter. Also, layer structure can be seen in the granule. This structure may be formed by annual growth of the cryanobacteria.

The surface of cryoconite granules are densely covered with flamentous cyanobacteria (blue-green algae, red colored flouresence). Cyanobacteria entangle each other and keep the spherical shape of the granules.

Living cyanobacteria distribute only on the surface of the granules. There is no living cyanobacteria inside the granule due to no light availability for photosysthesis.

Bacteria can be observed on the cyanobacteria. The bacteria decompose organic matter in the granule such as dead body of algae.

Scanninc microscopic images of cryoconite
Optical and flourecent microscopic images of cryoconite.
Structure of a cryoconite granule (cross section)
Related Papers
  • Takeuchi, N., Kohshima, S., and Seko, K. (2001): Structure, formation, darkening process of albedo reducing material (cryoconite) on a Himalayan glacier: a granular algal mat growing on the glacier. Arctic, Antarctic, and Alpine Research, 33, 115-122. [Abstract]
  • Takeuchi, N., Kohshima, S., Goto-Azuma, K., and Korner, R. M. (2001): Biological characteristics of dark colored material (cryoconite) on Canadian_Arctic glaciers (Devon and Penny ice cap), Proceeding of the Memoirs of National Institute of Polar Research, Special Issue, 54, 495-505. [Abstract]
  • Takeuchi, N. (2002): Optical characteristics of cryoconite (surface dust) on glaciers: the relationship between light absorbency and the property of organic matter contained in the cryoconite. Annals of Glaciology, 34, 409-414. [Abstract]


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