Microbial Community Analysis of Colored Snow from an Alpine Snowfield in Northern Japan Reveals the Prevalence of Betaproteobacteria with Snow Algae

Abstract

Psychrophilic algae blooms can be observed coloring the snow during the melt season in alpine snowfields. These algae are important primary producers on the snow surface environment, supporting the microbial community that coexists with algae, which includes heterotrophic bacteria and fungi. In this study, we analyzed the microbial community of green and red-colored snow containing algae from Mount Asahi, Japan. We found that <i>Chloromonas</i> spp. are the dominant algae in all samples analyzed, and <i>Chlamydomonas</i> is the second-most abundant genus in the red snow. For the bacterial community profile, species belonging to the subphylum <i>Betaproteobacteria</i> were frequently detected in both green and red snow, while members of the phylum <i>Bacteroidetes</i> were also prominent in red snow. Furthermore, multiple independently obtained strains of <i>Chloromonas</i> sp. from inoculates of red snow resulted in the growth of <i>Betaproteobacteria</i> with the alga and the presence of bacteria appears to support growth of the xenic algal cultures under laboratory conditions. The dominance of <i>Betaproteobacteria</i> in algae-containing snow in combination with the detection of <i>Chloromonas</i> sp. with <i>Betaproteobacteria</i> strains suggest that these bacteria can utilize the available carbon source in algae-rich environments and may in turn promote algal growth.