takeuchi_2003.htm
Bulletin of Glaciological Research 20 (2003)
21-27
©Japanese Society of Snow and Ice
Effect of cryoconite and snow algal communities on surface albedo on maritime glaciers in south Alaska
Nozomu TAKEUCHI1, Shiro KOHSHIMA2 and Takahiro SEGAWA2
1 Research Institute for Humanity and Nature, 335 Takashimacho, Kamigyo-ku, Kyoto-city, Kyoto 602-0878 Japan
2 Dep. Biological Sciences, Graduate School of Bioscience and Biotechnology (c/o Faculty of Science), Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 Japan
Abstract
In order to evaluate the effect of cryoconite on surface albedo on glaciers, surface albedo, characteristics of cryoconite, and snow algal community were investigated on two maritime glaciers; Worthington and Matanuska Glaciers in south Alaska, U.S.A. The surface albedo in the ice area ranged from 0.37 to 0.74 and the mean was 0.53. The amount of cryoconite on the glacier surface ranged from 0.2 to 14 g m-2 and the mean was 3.8 g m-2. Organic matter content in the cryoconite ranged from 1.0 to 9.8 % and the mean was 4.7 %. Snow algal community on the glaciers was dominated by three green algae, which were Mesotaenium bregrenii, Ancylonema Nordenskioldii and Chlamydomonas nivalis. The cell volume biomass of the snow algae ranged from 0.015 to 0.056 mL m-2 and the mean was 0.039 m-2. As compared with an inland glacier of Alaska, Gulkana Glacier, the effect of cryoconite on glacial surface albedo seemed to be smaller in the two maritime glaciers in this study. The surface albedo is higher and amount of cryoconite is smaller in the maritime glaciers than the inland glacier. The organic matter content and algal biomass are smaller in the maritime glaciers than the inland glacier. The smaller amount of cryoconite and algal biomass on the maritime glaciers may be caused by washing of cryoconite and algae out of the glaciers by large amounts of running meltwater on the bare ice surface. The meltwater can be produced more on the maritime glaciers, since the ablation rate is higher than on the inland glacier surface.
