Influence of Temperature and Precipitation on the Taxonomic Diversity of Snow Algae Microbial Communities in the Beartooth Mountains

Abstract

Snow algae increase the rate of snow melt due to its colorful red pigmentation which decreases the albedo of snow. Bacteria play a key role in snow algae’s ability to survive winter conditions as they assist in inter-kingdom nutrient cycling. In this project, we seek to understand the taxonomic composition of the bacterial community as temperature and precipitation change post-spring thaw. Temperature and precipitation data were collected from the NRCS website with data from the Beartooth Lake SNOTEL site near sample collection locations. Using snow algae samples collected in July 2024 and June, July, and August 2025, DNA was extracted. PCR was performed on the DNA with 16S barcoding to amplify and label the rRNA gene for Nanopore sequencing. Gel electrophoresis was performed to confirm the presence of the PCR product. Using RStudio and MicrobiomeAnalyst, we compared the beta diversity for monthly comparisons. We hypothesized that as temperature and precipitation increased, bacterial taxonomic diversity would increase. We identified statistically significant differences in month to month comparisons for temperature and precipitation changes using PERMANOVA and ANISOM testing. Using temperature and precipitation ordination plots, we identified a positive trend in temperature and precipitation along with community diversity post “spring thaw.” As temperature increased and precipitation decreased, we observed more diversity in the microbial communities, corresponding to a p-value of 0.001. Herein, we report our results towards the comprehensive understanding of temperature and precipitation effects on the bacterial community taxonomic composition of snow algae blooms in the Beartooth Mountains for monthly comparisons.