Diversity, distribution, and function of bacteria in the supraglacial region hit by glacial lake outburst flood in northern Pakistan

Background: Glaciers of the Hindu Kush region are highly susceptible to climate change. Recently, a severe glacial lake outburst flood (GLOF) hit the supraglacial region at the frontier of Dook Pal Glacier. Information on the bacterial community in a freshly appeared supraglacial lake after GLOF is essential to probe the bacterial distribution pattern after immediate unlocking from the supraglacial region. After GLOF, geochemistry and bacterial diversity, distribution, community structure, and function were examined in the lake-debris and melt-water. Results: In general, concentrations of dissolved free amino acids were similar between lake-debris and melt-water, potentially toxic elements and cations were greater in lake-debris, and anions concentrations were greater in melt-water. In addition, there was comparable diversity in the glacial melt-water and lake-debris; Proteobacteria dominated in lake-debris (33.1–94.5%), while Proteobacteria (36.7–50.5%) and Firmicutes (44–62%) dominated in melt-water. It is more likely that Proteobacteria and Firmicutes shifted towards melt-water after GLOF, creating an uneven distribution of communities in the lake-debris; however, a relatively even distribution was maintained in melt-water. Genes responsible for metabolism and energy production were higher in lake-debris than in melt-water bacteria; whereas, genes for other cellular mechanisms were higher in melt-water than in lake-debris bacteria. Conclusions: This study offers valuable datasets in understanding the bacterial diversity, distribution and function as a consequence of GLOF at the glacial frontier.