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GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L21502, doi:10.1029/2006GL027819, 2006

Spatial distribution and abundance of red snow algae on the Harding Icefield, Alaska derived from a satellite image

Nozomu Takeuchi

Graduate School of Science and Technology, Chiba University, Chiba, Japan


Roman Dial

Department of Environmental Science, Alaska Pacific University, Anchorage, Alaska, USA


Shiro Kohshima

School of Bioscience and Biotechnology, Tokyo Institute of Technology, Tokyo, Japan


Takahiro Segawa

National Polar Research Institute, Transdisciplinary Research Integration Center, Tokyo, Japan


Jun Uetake

School of Bioscience and Biotechnology, Tokyo Institute of Technology, Tokyo, Japan


Abstract

Red snow caused by algal bloom is common on glaciers and snowfields worldwide. Description of spatial distributions of snow algal blooms is important for understanding snow algae's unique life in an extremely cold environment and for determining the effect of algae through the reduction of surface albedo. Here we present the spatial distribution of red snow algae on the Harding Icefield, Alaska retrieved from a satellite image. Field observations on the icefield conducted in August 2001 revealed visible red snow, particularly near the snowline. Field measurements of spectral reflectance on the surface revealed the specific spectral absorption of algal pigments. We found a significant correlation between snow algal biomass and a reflectance ratio of SPOT (Satellite Probatoire d' Observation de la Terre) satellite band of wavelength 610–680 nm to band 500–590 nm. Using this relationship between the reflectance ratio and algal biomass, we estimated the distribution and abundance of red snow across the icefield using a SPOT satellite image. The spatial distribution of red snow on the icefield obtained by mapping the reflectance ratio matched field observations across the icefield with more red algal blooms on the continental than the maritime side of the icefield. Area averaged mean carbon content estimated from the red algal biomass for the icefield on the image was 1.2 kg km−2.

Received 9 August 2006; accepted 6 October 2006; published 7 November 2006.

Index Terms: 0456 Biogeosciences: Life in extreme environments; 0480 Biogeosciences: Remote sensing; 0716 Cryosphere: Cryobiology (0475); 0720 Cryosphere: Glaciers; 0736 Cryosphere: Snow (1827, 1863).

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Citation: Takeuchi, N., R. Dial, S. Kohshima, T. Segawa, and J. Uetake (2006), Spatial distribution and abundance of red snow algae on the Harding Icefield, Alaska derived from a satellite image, Geophys. Res. Lett., 33, L21502, doi:10.1029/2006GL027819.