Snow algal blooms observed in Mt. Echigo-Komagatake, Niigata prefecture, Japan（新潟県の越後駒ヶ岳で観察された雪氷藻類の大繁殖）

Snow algae are photosynthetic microbes growing on snowpacks and are commonly observed in mountain areas in Japan. In this study, we report the snow algal blooms observed in Mt. Echigo-Komagatake located in Niigata prefecture, Japan. Field investigation was conducted in late June of 2021 on a snow patch located in an alpine zone at an altitude of 2000 m above sea level. Patches of snow with red, green, or brown color were observed on the snowpack. Microscopic observation showed that the colored snow contained various morpho-types of snow algal cells, which appeared to be similar to those previously reported in Japan. The algal communities of the colored snow were mostly dominated by red spherical cells, which is likely to be Sanguina nivaloides, and consistent with those of the red snow reported in other alpine snowpacks in Japan. However, some samples showed a community consisting of various cell types, including multiple species of genus Chloromonas. The difference in community structure may be due to distance from vegetation around the snow patch, nutrient conditions of the snow, and/or growth period of the algae. The snow algal blooms of Mt. Echigo-Komagatake can be characterized by the appearance of various colors and algal communities on a snowpack.