Illuminating the dynamic rare biosphere of the Greenland Ice Sheet's Dark Zone

Gokul, J. K., Cameron, K. A. , Irvine-Fynn, T. D.L., Cook, J. M., Hubbard, A., Stibal, M., Hegarty, M., Mur, L. A.J. and Edwards, A. (2019) Illuminating the dynamic rare biosphere of the Greenland Ice Sheet's Dark Zone. FEMS Microbiology Ecology, 95(12), fiz177. (doi: 10.1093/femsec/fiz177) (PMID:31697309)

Abstract

Greenland's Dark Zone is the largest contiguous region of bare terrestrial ice in the Northern Hemisphere and microbial processes play an important role in driving its darkening and thereby amplifying melt and runoff from the ice sheet. However, the dynamics of these microbiota have not been fully identified. Here we present joint 16S rRNA gene and 16S rRNA (cDNA) comparison of input (snow), storage (cryoconite), and output (supraglacial stream water) habitats across the Dark Zone over the melt season. We reveal that all three Dark Zone communities have a preponderance of rare taxa exhibiting high protein synthesis potential (PSP). Furthermore, taxa with high PSP represent highly connected ‘bottlenecks’ within community structure, consistent with their roles as metabolic hubs. Finally, low abundance-high PSP taxa affiliated with Methylobacterium within snow and stream water suggest a novel role for Methylobacterium in the carbon cycle of Greenlandic snowpacks, and importantly, the export of potentially active methylotrophs to the bed of the Greenland Ice Sheet. By comparing the dynamics of bulk and potentially active microbiota in the Dark Zone of the Greenland Ice Sheet we provide novel insights into the mechanisms and impacts of the microbial colonization of this critical region of our melting planet.

• Item Type: Articles
• Additional Information: This work was supported by a Royal Society grant [RG130314] to AE and TIF while JKG was supported by a South African National Research Foundation fellowship. KAC acknowledges funding from the European Union's Horizon 2020 – Research and Innovation Framework Programme under the Marie Skłodowska-Curie grant [agreement no. 663830]. Financial support was also provided to KAC by the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment. AE is grateful for Leverhulme Trust Research fellowship [RF-2017-652\2] and NERC [NE/S001034/1], which eased completion of the work.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cameron, Dr Karen
• Authors: Gokul, J. K., Cameron, K. A., Irvine-Fynn, T. D.L., Cook, J. M., Hubbard, A., Stibal, M., Hegarty, M., Mur, L. A.J., and Edwards, A.
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences > Earth Sciences
• Journal Name: FEMS Microbiology Ecology
• Publisher: Wiley
• ISSN: 0168-6496
• ISSN (Online): 1574-6941
• Published Online: 07 November 2019
• Copyright Holders: Copyright © 2019 FEMS
• First Published: First published in FEMS Microbiology Ecology 95(12):fiz177
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher