takeuchi_2005.htm
Bulletin of Glaciological Research 22 (2005)
1-8
©Japanese Society of Snow and Ice
A large amount of biogenic surface dust (cryoconite)
on a glacier in the
Qilian Mountains, China
Nozomu TAKEUCHI1, Yoshihiro MATSUDA2, Akiko SAKAI2 and Koji FUJITA2
1 Research Institute for Humanity and Nature,
335 Takashimacho Kamigyo-ku Kyoto-city Kyoto
602-0878 Japan
2 Graduate School of Environmental Studies,
Nagoya University, Nagoya 464-8601, Japan
Abstract
Surface dust on glaciers can significantly affect surface albedo and subsequently the mass balance of the glaciers. The characteristics of surface dust (cryoconite) were investigated fn September 2002 on the July 1st Glacier (Qiyi Glacier) tn the Qilian Mountains, China. The bare ice surface of the glacier was mostly covered by fine brown dust. The amount of the surface dust (dry weight) ranged from 30.4 to 873 gm-2 (mean: 292 gm-2, standard deviation: 196), which fS significantly higher than that on glaciers fn other parts of the world, and is equivalent to that on Himalayan glaciers on which the large amounts of dust have been reported. An analysis of organic matter and microscopy of the surface dust revealed that the dust contained high levels of organic matter, including living cyanobacteria. This suggests that the dust consists not only of deposit of wind-blown desert sand, but is also a product of microbial activity on the glacier. Measurements of surface albedo showed that the mean surface albedo tn the ice area was smaller than that of the clean bare ice surface, suggesting that the albedo was significantly reduced by the surface dust. Large amounts of surface dust may be due to abundant windblown deposits of desert sand and high biological productivity on the glacial surface, probably a common characteristic of Asian glaciers.
