Diversity and abundance of microbial assemblages in glacial meltwaters at the western margin of the Greenland Ice Sheet

Microbial processes that mineralize organic carbon and enhance solute production at the bed of polar ice sheets could be of a magnitude sufficient to affect global elemental cycles. To investigate the biogeochemistry of polar glacial meltwater microbial ecosystems, we analyzed water discharged during the summer of 2011, 2012 and 2013 from 1) North River, which flows through the Pituffik region of the Thule Basin (2011, 2013) and 2) Russell Glacier, a land-terminating outlet glacier near Kangerlussuaq (2012, 2013) both at the western margin of the Greenland Ice Sheet. The structure and diversity of microbial assemblages was investigated through high throughput sequence analysis of the small subunit (16S or 18S) rRNA genes. Microbial abundances of total and active microbes were determined by epifluorescence microscopy using the DNA stains DAPI and Acridine Orange and the electron transport system stain tetrazolium salt 5-cyano-2,3-ditolyltetrazolium chloride (CTC). Citation: Markus Dieser, Erik L J E Broemsen, Karen A Cameron, Gary M King, Amanda Achberger, Kyla Choquette, Birgit Hagedorn, Ron Sletten, Karen Junge and Brent C Christner (2014), Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland Ice Sheet, The ISME Journal 8: 2305-2316, doi:10.1038/ismej.2014.59.