Nakashima Tomomi, Uetake Jun, Segawa Takahiro, Procházková Lenka, Tsushima Akane, Takeuchi Nozomu
Graduate School of Science, Chiba University, Chiba, Japan.
Field Science Center for Northern Biosphere, Hokkaido University, Sapporo, Japan.
Front Plant Sci. 2021 Jul 5;12:689119. doi: 10.3389/fpls.2021.689119. eCollection 2021.
Snow algae are photosynthetic microbes that inhabit the melting snow surface in alpine and polar regions. We analyzed the pigment and species composition of colored snow collected on Mt. Tateyama in Japan during the melting seasons of 2015 and 2016. High-performance liquid chromatographic analyses of the pigments extracted from the colored snow showed that their composition varied within the study area and were classified into four types: Type A (astaxanthin-monoester dominant), Type B (medium astaxanthin-monoester content), Type C (abundant primary carotenoids and free-astaxanthin), and Type D (abundant primary carotenoids and astaxanthin diesters). Types A and B were most commonly observed in the study area, whereas Types C and D appeared only at specific sites. Analysis of the 18S ribosomal RNA (18S rRNA) gene revealed six major amplicon sequence variants (ASVs) of snow algae, belonging to the , and groups. The relative abundance of the algal ASVs showed that was dominant (>48%) in both Types A and B, suggesting that the difference in astaxanthin abundance between the two types was caused by the production of pigments in the algal cells. The algal community structures of Types C and D differed from those of Types A and B, indicating that the primary carotenoids and astaxanthin diesters were derived from certain algal species in these types. Therefore, astaxanthin-rich algae mostly induced the red snow that appeared widely in this alpine area; however, they were partially dominated by or algae, causing different pigment compositions.
雪藻是一种光合微生物，栖息于高山和极地地区正在融化的雪表面。我们分析了2015年和2016年融雪季节在日本立山采集的有色雪的色素和物种组成。对从有色雪中提取的色素进行高效液相色谱分析表明，其组成在研究区域内有所不同，并分为四种类型：A型（以虾青素单酯为主）、B型（虾青素单酯含量中等）、C型（富含初级类胡萝卜素和游离虾青素）和D型（富含初级类胡萝卜素和虾青素二酯）。A型和B型在研究区域最为常见，而C型和D型仅出现在特定地点。对18S核糖体RNA（18S rRNA）基因的分析揭示了雪藻的六个主要扩增子序列变体（ASV），属于、和类群。藻类ASV的相对丰度表明，在A型和B型中均占主导地位（>48%），这表明两种类型之间虾青素丰度的差异是由藻类细胞中色素的产生引起的。C型和D型的藻类群落结构与A型和B型不同，表明初级类胡萝卜素和虾青素二酯来自这些类型中的某些藻类物种。因此，富含虾青素的藻类主要导致了在这个高山地区广泛出现的红雪；然而，它们部分被或藻类主导，导致了不同的色素组成。
