The so-called Dark Zone of the Greenland ice sheet is a conspicuous band of dark bare ice that covers ca 10 000 km² of the western margin of the ice sheet. It is a biologically active surface where extensive microbial colonization drives regional surface albedo reduction and enhanced ablation. Microbial processes associated with Greenland’s dark ice surface also contribute to the cycling and hydraulic export of microbial biomass, organic carbon and nutrients in significant quantities to downstream ecosystems.

A new paper published in FEMS Microbiology Ecology, led by Jerry Gokul and her colleagues from Aberystwyth University and coauthored by Marek, presents an integrated study of community structure, connectivity and its functional potential within three principal bacterial habitats found within the Dark Zone: snow (input), cryoconite hole (storage) and runoff (output) using analysis of both 16S rRNA gene and 16S rRNA (cDNA).

The study revealed that rare bacterial taxa are likely to be disproportionately active and appear central to the structure of the supraglacial communities, and may play under-appreciated roles within the carbon cycle of the Greenland ice sheet. It provides novel insights into the mechanisms and impacts of the microbial colonization of this critical region of our melting planet.

Gokul JK, Cameron KA, Irvine-Fynn TDL, Cook JM, Hubbard A, Stibal M, Hegarty M, Mur LAJ, Edwards A (2019) Illuminating the dynamic rare biosphere of the Greenland Ice Sheet’s Dark Zone. FEMS Microbiology Ecology 95:fiz177 doi: 10.1093/femsec/fiz177