A preliminary investigation of microbial communities on the Athabasca Glacier within deposited organic matter†

Glacier ecosystems are shrinking at an accelerating rate due to changes in climate and also increased darkening from allochthonous and autochthonous carbon leading to subsequent changes in the absorption of light, associated heat, and microbial communities. In this study, in combination with measurement of nutrients and polycyclic aromatic hydrocarbons (PAHs), compositions of microbial communities on surfaces of the Athabasca Glacier (Canadian Rockies, Alberta, Canada) were measured and characterized by use of metabarcoding and scanning electron microscopy. Three matrices, glacier ice, cryoconite hole, and supraglacial surface sediment, were analyzed to gain a first insight into microbial communities on the Athabasca Glacier. Both, eukaryotic and prokaryotic microbial biodiversity was positively correlated with PAH concentrations of Benzo[a]pyrene, Indeno[123-cd]pyrene, Chrysene, Benzo[ghi]perylene, and Dibenz[ah]anthracene. Furthermore, the combustion of petroleum was identified as a major source of PAHs found on the Athabasca Glacier. The high levels of deposition and nutrients observed in this study may lead to an increase in microbial activity and growth that could accelerate glacier melting by further reducing surface albedo. More research is needed to understand the impacts of microbial activity and biodiversity on surface albedo and its effects on glacier meltwater, in the context of global climate change.