Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel

Dubnick, Ashley J.; Spietz, Rachel L.; Danielson, Brad D.; Skidmore, Mark L.; Boyd, Eric S.; Burgess, Dave; Dhoonmoon, Charvanaa; Sharp, Martin

doi:https://doi.org/10.5194/tc-17-2993-2023

Articles | Volume 17, issue 7

https://doi.org/10.5194/tc-17-2993-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-17-2993-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 7

Research article

|

21 Jul 2023

Research article |

| 21 Jul 2023

Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel

Ashley J. Dubnick, Rachel L. Spietz, Brad D. Danielson, Mark L. Skidmore, Eric S. Boyd, Dave Burgess, Charvanaa Dhoonmoon, and Martin Sharp

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Final revised paper (published on 21 Jul 2023)
Supplement to the final revised paper
Preprint (discussion started on 21 Feb 2023)
Supplement to the preprint

Interactive discussion

Status: closed

RC1:
'Comment on tc-2022-240', Zac Cooper, 22 Mar 2023

This manuscript is exceptionally well-written. The methods are employed appropriately and the findings are clear and concisely presented. This manuscript benefits from the obvious care taken to employ interdisciplinary methods to explain a complex setting which helps increase the accessibility of this study to scientists across disciplines interested in the cryosphere. In this study, the details of the geochemical, physical, and microbiological aspects of a subglacial meltpond are interpreted with care to explore the biogeochemical of alteration of the chemical composition of waters resulting from glacial melt. These data highlight the importance of understanding the biological influence on this geological system while also demonstrating the habitability of this rarely studied ecosystem. Given the rapid change in polar and alpine regions, this work is an excellent contribution to the field and our understanding of the past, present, and future of the cryosphere. I found no errors in the text and happily recommend accepting this manuscript for publication as is.

Citation: https://doi.org/10.5194/tc-2022-240-RC1
- AC1: 'Reply on RC1', Ashley Dubnick, 17 May 2023
  
  Dear Zac Cooper,
  Thank you for your time and effort in reviewing our paper and providing such positive feedback. We’re glad you enjoyed reading it!
  
  Citation: https://doi.org/10.5194/tc-2022-240-AC1
RC2:
'Comment on tc-2022-240', Anonymous Referee #2, 23 Mar 2023

It was a joy to read the manuscript by Dubnick and colleagues. The paper describes in detail the geochemical transformation (evolution) of late-season glacial meltwater as it undergoes freezing subglacially over winter. To my knowledge this is the first study of the type that can provide empirical data on these processes in a very interesting field site that can act as a natural laboratory. Despite the particular nature of the study site, the results presented here are of broader relevance and can inform on a wider array of subglacial systems. They exemplify what microbial and biogeochemical processes can occur subglacially in the context of subglacial environments as being active microbial habitats. They do so in a quantitative way by combining geochemical models, geochemical and microbial observations and go beyond simple data reporting often the case in similar studies. The manuscript is extremely well written, with great context and explanation for both expert and non-expert readers, well within the relevant scopes of the Cryosphere journal.
However, before recommending the article for publication, there are some minor comments that I believe would need addressing or clarifying:

Citation: https://doi.org/10.5194/tc-2022-240-RC2
- AC2: 'Reply on RC2', Ashley Dubnick, 17 May 2023
  
  Dear anonymous reviewer,
  Thank you for your time and effort in reviewing our paper. We’re thrilled that you enjoyed reading this manuscript and that you appreciated our in-depth and interdisciplinary data analysis. Your comments below are all relevant and appropriate and have led to improvements in the paper. We hope you’re satisfied with our responses. Thank you!
  
  Citation: https://doi.org/10.5194/tc-2022-240-AC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

ED: Publish subject to minor revisions (review by editor) (13 Jun 2023) by Elizabeth Bagshaw

AR by Ashley Dubnick on behalf of the Authors (13 Jun 2023) Author's response Author's tracked changes Manuscript

ED: Publish as is (14 Jun 2023) by Elizabeth Bagshaw

AR by Ashley Dubnick on behalf of the Authors (16 Jun 2023)

Short summary

At the end of an Arctic winter, we found ponded water 500 m under a glacier. We explored the chemistry and microbiology of this unique, dark, and cold aquatic habitat to better understand ecology beneath glaciers. The water was occupied by cold-loving and cold-tolerant microbes with versatile metabolisms and broad habitat ranges and was depleted in compounds commonly used by microbes. These results show that microbes can become established beneath glaciers and deplete nutrients within months.