Analysis of Antarctic soil algae by the direct observation using the contact slide method

The species composition and distribution of soil algae in situ were investigated by the direct observation using the contact slide method with reference to the available water in soils of the Yukidori Valley, Langhovde, Antarctica. Glass slides were vertically buried at five sites with a few meters intervals along a stream for a year from January 1988. Eleven taxa of Cyanophyceae, eight taxa of Chlorophyceae and four taxa of Bacillariophyceae were recognized on the collected glass slides. Actinotaenium cucurbita (RALFS) TEILING and Pinnularia borealis EHRENB. were often dominant. The results of the observation by the scanning electron microscope showed that diatoms secreted thin mucilage, but a filamentous blue-green alga, Lyngbya martensiana MENEGH. secreted thick mucilage and adhered to the surface of glass slides. Both the species number and the algal cell number of the soil algae and the chlorophyll content in soils were well related to the water content of soils. Values of these three items were high at the nearest transect points to the stream where the water content of soils was high, and suddenly decreased at a few meters distance from the stream where the water content of soils was low