Snow algae community on a Himalayan glacier, Glacier AX010 East Nepal : Relationship with glacier summer mass balance

An altitudinal change of the snow algae communitis on a Himalayan glacier, Glacier AX010 (4950 -5380 m a.s.l.), Shorong region of East Nepal, was quantitatively analyzed to clarify the relationship between the glacier algal community and glacier summer mass balance. The results were compared with that of another Himalayan Clean Type glacier, Yala glacier (Yoshimura et al., 1997). In this glacier, 5 species of snow algae including 4 species reported from Yala glacier were observed. In both glacier, the algal biomasses were in a similar level at the same altitude and decreased as the altitude increase at a similar rate. The structure of algal community represented by the proportion of each species to the total algal biomass differed by altitude and summer mass balance estimated by stake measurement. The algal community on this glacier could be divided into the following two types : Type 1 community with 5 species highly dominated by C. brebissonii observed in the minus mass balance area from terminus to 5180 m a.s.l. and Type 2 community with 4 species dominated by the Oscillatoriacean alga observed in the plus mass balance area above 5200 m a.s.l. In community structure, Type 1 and Type 2 community corresponded to the community observed in the lower part (5100-5200 m a.s.l.) and the middle part (5200-5300 m a.s.l.) of Yala glacier, respectively. Relationship between snow algal community and summer mass balance was discussed. The results suggest that the snow algal community could be useful as an indicator of summer mass balance and equilibrium line of this type of glaciers.