Sampling activity was funded by the INTERACT Transnational Access program and the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 675546 (MicroArctic network). The latter also provided funding support for GV and AH. Funding support was also provided through the NERC grant NE/J02399X/1 awarded to GB, AA and MY. AA also acknowledges a grant from the Aarhus University Research Fund.
Journal of Glaciology
Distant glacial areas are interconnected by a complex system of fractures and water channels which run in the glacier interior and characterize the englacial realm. Water can slowly freeze in these channels where the slow freezing excludes air bubbles giving the ice a clear aspect. This ice is uplifted to the surface ablation zone by glacial movements and can therefore be observed in the form of clear surface ice bands. We employed an indirect method to sample englacial water by coring these ice bands. We were able, for the first time, to compare microbial communities sampled from clear (i.e. frozen englacial water bands) and cloudy ice (i.e. meteoric ice) through 16S rRNA gene sequencing. Although microbial communities were primarily shaped and structured by their spatial distribution on the glacier, ice type was a clear secondary factor. One area of the glacier, in particular, presented significant microbial community clear/cloudy ice differences. Although the clear ice and supraglacial communities showed typical cold-adapted glacial communities, the cloudy ice had a less defined glacial community and ubiquitous environmental organisms. These results highlight the role of englacial channels in the microbial dispersion within the glacier and, possibly, in the shaping of glacial microbial communities.
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright © The Author(s), 2021. Published by Cambridge University Press
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Varliero, G., Holland, A., Barker, G., Yallop, M., Fountain, A., & Anesio, A. (2021). Glacier clear ice bands indicate englacial channel microbial distribution. Journal of Glaciology, 1-13. doi:10.1017/jog.2021.30