Determining the Location of Snow Algae After Snow Recession: Sequencing snow algae genomes in snow, soil and meltwater pools

Abstract

During late summer, snowfields and glaciers in alpine and subalpine environments often develop a red tint. This coloring is produced by snow algae and plays a large role in lowering the bioalbedo of snow, contributing to an estimated 11% of snow and glacial recession. Because many species of snow algae have not been successfully cultured in laboratory settings, analysis of their life cycle is a topic of ongoing research. Alpine microorganisms are often dispersed by meltwater into runoff and eventually the underlying soil during spring and summer melt. We hypothesize this may serve as a potential mechanism of annual snow algae dispersal. This study utilized environmental snow, soil, and biofilm samples collected from the Beartooth Mountains and Glacier National Park in July of 2025. Samples were analyzed using both microscopy and sequencing. Qualitative observations and cell counts were conducted with a light microscope, while DNA extraction followed by PCR amplification of the 18S rRNA gene and ITS region allowed for assessment of eukaryotic biodiversity. Both microscopy and DNA analysis suggest clear evidence of the order Chlamydomonadales in snow and biofilm samples, with snow samples containing Chlamydomonas (Sanguina) and biofilm samples containing Haematococcus as the dominant genus; soil samples showed little to no presence of snow algae. These predictions could ultimately help researchers anticipate areas of snowpack that may be susceptible to more rapid melt during blooms, and therefore which downstream ecosystems would be most affected.