Microbes in High Arctic Snow and Implications for the Cold Biosphere

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.

Microbial Cell Retention in a Melting High Arctic Snowpack, Svalbard

“…If particles and bacteria remain in the snowpack rather than following the meltwater, as our results suggest, an elevated concentration of associated chemicals (such as NO 3 -) might be expected in the remaining snow. This is because both nitrification, which is typical among bacteria associated with debris (Hodson et al, 2005), and cell-lysis, which may be caused by osmotic stress in the very diluted meltwater (Harding et al, 2011), might release solutes to the surrounding snow and meltwater. Furthermore, chemical dry deposition and sublimation of snow-water could also influence the snowpack concentrations and thereby the elution response.…”

Ecology and biogeochemistry of cyanobacteria in soils, permafrost, aquatic and cryptic polar habitats

“…Secondly, it has been suggested that soil cyanobacteria may represent historical signatures of aquatic cyanobacterial mat biomass distributed from lake margins by aeolian processes (Vincent 2000;Harding et al 2011). This suggestion is supported by the demonstration that cyanobacteria in soils of the low altitude maritime Miers Valley were similar to those from nearby microbial mats (Wood et al 2008b).…”

Microbial metabolism directly affects trace gases in (sub) polar snowpacks

“…To this end, research into the aerobiome and polar environments have demonstrated that microorganisms in aerial fallout remain viable, as cultures from aerobiological samples can grow under favourable conditions [26,27]. Furthermore, the presence of microbes in remote, low-nutrient, low-water, very cold environments such as polar glacial surfaces and their snowpacks is well established [28,29].…”