MICROBIAL ASSEMBLAGES WITHIN AND OUTSIDE SNOW ALGAE BLOOMS ACROSS THE ROCKY MOUNTAINS

Snow algae blooms are common during the summer in alpine regions of the planet. These algae are important primary producers on the snow surface and support a diverse microbial community. Pigmented snow algae also lower albedo and accelerate snow melt but their distribution on snowpack is typically patchy. Due to their roles in biogeochemical cycling and accelerating melt, there is increasing interest in understanding the factors that constrain the distribution of snow algae on snowpack. In the present study, we compared microbial assemblages from blooming (red snow) and non-bloom (white snow) areas on the same snowfields located across the US side of the Rocky Mountains. We targeted geographic regions that are known to vary in nitrogen and phosphorus deposition to better constrain how these essential nutrients impact the composition and abundance of snow algae as well as other snow microbes. We also evaluated the connectivity between snow algae and other microbes to better understand the complexity of biological interactions within algal blooms versus areas where snow algal blooms were not present. Our study provides insight into community composition of snow algal blooms and the factors underlying their heterogeneous distribution on alpine snowpack.