Observation of yukimarimo on the snow surface of the inland plateau, Antarctic ice sheet

Many small balls were observed on the surface of the ice sheet at Dome Fuji station (77 degrees 19'01"S, 39 degrees 42'12"E; 3810 m a.s.l.), located at the highest point in Dronning Maud Land, Antarctica, during the first overwintering of the Japanese Antarctic Research Expedition (JARE) in 1995. Solid-needle-type (SN) surface hoar crystals formed the balls. Figure 1 shows a cluster of the balls; their diameters range from 5 to 30 mm. They were naturally collected by wind. They look quite similar to globular marimo plants (Cladophora sauteri Kutzing; Sakai, 1964) which are observed in Lake Akan in Hokkaido, Japan. Thus, we named them ``yukimarimo'' (``yuki'' means snow in Japanese). They were fragile, but did not break apart when handled carefully. The average density of yukimarimo was about 50 kg m super(-) super(3) . The article provides photos and further description.