Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel
Subglacial environments comprise ∼10 % of Earth's land surface, host active microbial ecosystems, and are important components of global biogeochemical cycles. However, the broadly inaccessible nature of subglacial systems has left them vastly understudied, and research to date has been limited...
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ftcopernicus:oai:publications.copernicus.org:tc108112 2023-08-15T12:40:03+02:00 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 2023-07-21 application/pdf https://doi.org/10.5194/tc-17-2993-2023 https://tc.copernicus.org/articles/17/2993/2023/ eng eng doi:10.5194/tc-17-2993-2023 https://tc.copernicus.org/articles/17/2993/2023/ eISSN: 1994-0424 Text 2023 ftcopernicus https://doi.org/10.5194/tc-17-2993-2023 2023-07-24T16:24:16Z Subglacial environments comprise ∼10 % of Earth's land surface, host active microbial ecosystems, and are important components of global biogeochemical cycles. However, the broadly inaccessible nature of subglacial systems has left them vastly understudied, and research to date has been limited to laboratory experiments or field measurements using basal ice or subglacial water accessed through boreholes or from the glacier margin. In this study, we extend our understanding of subglacial biogeochemistry and microbiology to include observations of a slushy pond of water that occupied a remnant meltwater channel beneath a polythermal glacier in the Canadian High Arctic over winter. The hydraulics and geochemistry of the system suggest that the pond water originated as late-season, ice-marginal runoff with less than ∼15 % solute contribution from subglacial sources. Over the 8 months of persistent sub-zero regional temperatures, the pond gradually froze, cryo-concentrating solutes in the residual water by up to 7 times. Despite cryo-concentration and the likely influx of some subglacial solute, the pond was depleted in only the most labile and biogeochemically relevant compounds, including ammonium, phosphate, and dissolved organic matter, including a potentially labile tyrosine-like component. DNA amplicon sequencing revealed decreasing microbial diversity with distance into the meltwater channel. The pond at the terminus of the channel hosted a microbial community inherited from late-season meltwater, which was dominated by only six taxa related to known psychrophilic and psychrotolerant heterotrophs that have high metabolic diversity and broad habitat ranges. Collectively, our findings suggest that generalist microbes from the extraglacial or supraglacial environments can become established in subglacial aquatic systems and deplete reservoirs of nutrients and dissolved organic carbon over a period of months. These findings extend our understanding of the microbial and biogeochemical evolution of subglacial ... Text Arctic Copernicus Publications: E-Journals Arctic The Cryosphere 17 7 2993 3012 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Subglacial environments comprise ∼10 % of Earth's land surface, host active microbial ecosystems, and are important components of global biogeochemical cycles. However, the broadly inaccessible nature of subglacial systems has left them vastly understudied, and research to date has been limited to laboratory experiments or field measurements using basal ice or subglacial water accessed through boreholes or from the glacier margin. In this study, we extend our understanding of subglacial biogeochemistry and microbiology to include observations of a slushy pond of water that occupied a remnant meltwater channel beneath a polythermal glacier in the Canadian High Arctic over winter. The hydraulics and geochemistry of the system suggest that the pond water originated as late-season, ice-marginal runoff with less than ∼15 % solute contribution from subglacial sources. Over the 8 months of persistent sub-zero regional temperatures, the pond gradually froze, cryo-concentrating solutes in the residual water by up to 7 times. Despite cryo-concentration and the likely influx of some subglacial solute, the pond was depleted in only the most labile and biogeochemically relevant compounds, including ammonium, phosphate, and dissolved organic matter, including a potentially labile tyrosine-like component. DNA amplicon sequencing revealed decreasing microbial diversity with distance into the meltwater channel. The pond at the terminus of the channel hosted a microbial community inherited from late-season meltwater, which was dominated by only six taxa related to known psychrophilic and psychrotolerant heterotrophs that have high metabolic diversity and broad habitat ranges. Collectively, our findings suggest that generalist microbes from the extraglacial or supraglacial environments can become established in subglacial aquatic systems and deplete reservoirs of nutrients and dissolved organic carbon over a period of months. These findings extend our understanding of the microbial and biogeochemical evolution of subglacial ... |
format |
Text |
author |
Dubnick, Ashley J. Spietz, Rachel L. Danielson, Brad D. Skidmore, Mark L. Boyd, Eric S. Burgess, Dave Dhoonmoon, Charvanaa Sharp, Martin |
spellingShingle |
Dubnick, Ashley J. Spietz, Rachel L. Danielson, Brad D. Skidmore, Mark L. Boyd, Eric S. Burgess, Dave Dhoonmoon, Charvanaa Sharp, Martin Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel |
author_facet |
Dubnick, Ashley J. Spietz, Rachel L. Danielson, Brad D. Skidmore, Mark L. Boyd, Eric S. Burgess, Dave Dhoonmoon, Charvanaa Sharp, Martin |
author_sort |
Dubnick, Ashley J. |
title |
Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel |
title_short |
Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel |
title_full |
Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel |
title_fullStr |
Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel |
title_full_unstemmed |
Biogeochemical evolution of ponded meltwater in a High Arctic subglacial tunnel |
title_sort |
biogeochemical evolution of ponded meltwater in a high arctic subglacial tunnel |
publishDate |
2023 |
url |
https://doi.org/10.5194/tc-17-2993-2023 https://tc.copernicus.org/articles/17/2993/2023/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
eISSN: 1994-0424 |
op_relation |
doi:10.5194/tc-17-2993-2023 https://tc.copernicus.org/articles/17/2993/2023/ |
op_doi |
https://doi.org/10.5194/tc-17-2993-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
7 |
container_start_page |
2993 |
op_container_end_page |
3012 |
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1774292746721296384 |