Microbes in High Arctic Snow and Implications for the Cold Biosphere

TLDR

We used molecular, microscopic, and culture methods to characterize microbial communities in snow and air at remote Canadian High Arctic sites. Snow and air samples from the Canadian High Arctic revealed diverse bacterial and eukaryotic communities, with SSU rRNA signatures indicating extensive local aerial transport and strong links to Arctic Ocean and regional mat microbiota, while also showing global distribution patterns across cold biosphere ecosystems.

Abstract

ABSTRACT We applied molecular, microscopic, and culture techniques to characterize the microbial communities in snow and air at remote sites in the Canadian High Arctic (Ward Hunt Island, Ellesmere Island, and Cornwallis Island, latitudes 74 to 83 o N). Members of the Bacteria and Eukarya were prevalent in the snow, and their small subunit (SSU) rRNA gene signatures indicated strong local aerial transport within the region over the preceding 8 months of winter snowpack accumulation. Many of the operational taxonomic units (OTUs) were similar to previously reported SSU rRNA gene sequences from the Arctic Ocean, suggesting the importance of local aerial transport processes for marine microbiota. More than 47% of the cyanobacterial OTUs in the snow have been previously found in microbial mats in the region, indicating that this group was also substantially derived from local sources. Viable cyanobacteria isolated from the snow indicated free exchange between the snow and adjacent mat communities. Other sequences were most similar to those found outside the Canadian Arctic but were from snow, lake and sea ice, glaciers and permafrost, alpine regions, Antarctica, and other regions of the Arctic, supporting the concept of global distribution of microbial ecotypes throughout the cold biosphere.