HR: 0800h
AN: B31A-0199    [Abstracts]
TI: Himalayan Ice Core Analyses With Snow Algae
AU: * Yoshimura, Y
EM: ystk@agr.tamagawa.ac.jp
AF: Faculty of Agriculture, Tamagawa University, 6-1-1 Tamagawa Gakuen, Machida, Tokyo, 194-8610 Japan
AU: Kohshima, S
AF: Department of Biological Sciences, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo, 152-8551 Japan
AU: Takeuchi, N
AF: Research Institute for Humanity and Nature, Kamigyo, Kyoto, 602-0878 Japan
AU: Seko, K
AF: Institute for Hydrospheric-Atmospheric Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan
AU: Fujita, K
AF: Institute for Hydrospheric-Atmospheric Sciences, Nagoya University, Chikusa, Nagoya, 464-8601 Japan
AB: Snow algae in a shallow ice core (7 m in length) from the Yala Glacier, Langtang region of Nepal, were examined for potential use in ice core analyses. Ice core samples taken at 5350 m a.s.l. in 1994, contained more than 7 species of snow algae. In a vertical profile of the algal biomass, 11 distinct algal layers were observed. Seasonal observation in 1996 at the coring site indicated most algal growth to occur from late spring to late summer. Pit observation in 1991, 1992 and 1994 indicated algal layer formation to take place annually. Delta $^{18}$O, chemical ions (Na$^{+}$, Cl$^{-}$, SO$_{4}$$^{2-}$, and NO$_{3}$$^{-}$) and microparticles failed to show any clear seasonal variation, particularly so at depths exceeding 2 m, possibly due to heavy melt-water percolation. Snow algae in the ice core would thus be accurate boundary markers of annual layers in the ice cores of this region. Algal biomass in each annual layer was noted to be quite closely correlated with the following two environmental indices calculated from air temperature and precipitation at Kyangjing (3,920 m a.s.l.), the village nearest the Yala Glacier: estimated mean snow cover thickness (MST) and estimated summer mass balance (SMB) ({\it n} = 6, {\it r} = -0.975, {\it P} $<$ 0.01; {\it n} = 6, {\it r} = -0.968, {\it P} $<$ 0.01, respectively). Both parameters reflect snow cover thickness on algal layers, which would be a major determinant of light available for algal growth on the glacier. The algal biomass was also found to be roughly correlated with air temperature ({\it n} = 7, {\it r} = 0.773, {\it P} $<$ 0.05) but it was not correlated with the density of particles in the layer, possible nutrient source for the snow algae. Snow algal biomass in an ice core should prove a good environmental marker for indicating summer mass balance which is important for understanding summer-accumulation-type glaciers in this region.
DE: 1863 Snow and ice (1827)
DE: 1615 Biogeochemical processes (4805)
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting