Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment
Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, subglacial biogeochemistry is not well understood, and the contribution of subglacial water to coastal ocean carbon and nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem i...
Published in: | Global Biogeochemical Cycles |
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ftmichigantuniv:oai:digitalcommons.mtu.edu:michigantech-p-2778 2023-05-15T13:31:55+02:00 Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment Vick‐Majors, Trista J. Michaud, Alexander B. Skidmore, Mark L. Turetta, Clara Barbante, Carlo Christner, Brent C. 2020-02-26T08:00:00Z https://digitalcommons.mtu.edu/michigantech-p/1790 https://doi.org/10.1029/2019GB006446 unknown Digital Commons @ Michigan Tech https://digitalcommons.mtu.edu/michigantech-p/1790 https://doi.org/10.1029/2019GB006446 Michigan Tech Publications subglacial organic matter Antarctica ice‐shelf‐cavity Department of Biological Sciences Biology text 2020 ftmichigantuniv https://doi.org/10.1029/2019GB006446 2022-01-23T10:40:28Z Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, subglacial biogeochemistry is not well understood, and the contribution of subglacial water to coastal ocean carbon and nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem is upstream from West Antarctica's Gould‐Siple Coast ~800 m beneath the surface of the Whillans Ice Stream. SLW hosts an active microbial ecosystem and is part of an active hydrological system that drains into the marine cavity beneath the adjacent Ross Ice Shelf. Here we examine sources and sinks for organic matter in the lake and estimate the freshwater carbon and nutrient delivery from discharges into the coastal embayment. Fluorescence‐based characterization of dissolved organic matter revealed microbially driven differences between sediment pore waters and lake water, with an increasing contribution from relict humic‐like dissolved organic matter with sediment depth. Mass balance calculations indicated that the pool of dissolved organic carbon in the SLW water column could be produced in 4.8 to 11.9 yr, which is a time frame similar to that of the lakes’ fill‐drain cycle. Based on these estimates, subglacial lake water discharged at the Siple Coast could supply an average of 5,400% more than the heterotrophic carbon demand within Siple Coast embayments (6.5% for the entire Ross Ice Shelf cavity). Our results suggest that subglacial discharge represents a heretofore unappreciated source of microbially processed dissolved organic carbon and other nutrients to the Southern Ocean. Text Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ross Ice Shelf Southern Ocean Whillans Ice Stream Michigan Technological University: Digital Commons @ Michigan Tech Antarctic Ross Ice Shelf Siple ENVELOPE(-83.917,-83.917,-75.917,-75.917) Siple Coast ENVELOPE(-155.000,-155.000,-82.000,-82.000) Southern Ocean The Antarctic West Antarctic Ice Sheet Whillans ENVELOPE(-64.250,-64.250,-84.450,-84.450) Whillans Ice Stream ENVELOPE(-145.000,-145.000,-83.667,-83.667) Global Biogeochemical Cycles 34 3 |
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Open Polar |
collection |
Michigan Technological University: Digital Commons @ Michigan Tech |
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ftmichigantuniv |
language |
unknown |
topic |
subglacial organic matter Antarctica ice‐shelf‐cavity Department of Biological Sciences Biology |
spellingShingle |
subglacial organic matter Antarctica ice‐shelf‐cavity Department of Biological Sciences Biology Vick‐Majors, Trista J. Michaud, Alexander B. Skidmore, Mark L. Turetta, Clara Barbante, Carlo Christner, Brent C. Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment |
topic_facet |
subglacial organic matter Antarctica ice‐shelf‐cavity Department of Biological Sciences Biology |
description |
Although subglacial aquatic environments are widespread beneath the Antarctic ice sheet, subglacial biogeochemistry is not well understood, and the contribution of subglacial water to coastal ocean carbon and nutrient cycling remains poorly constrained. The Whillans Subglacial Lake (SLW) ecosystem is upstream from West Antarctica's Gould‐Siple Coast ~800 m beneath the surface of the Whillans Ice Stream. SLW hosts an active microbial ecosystem and is part of an active hydrological system that drains into the marine cavity beneath the adjacent Ross Ice Shelf. Here we examine sources and sinks for organic matter in the lake and estimate the freshwater carbon and nutrient delivery from discharges into the coastal embayment. Fluorescence‐based characterization of dissolved organic matter revealed microbially driven differences between sediment pore waters and lake water, with an increasing contribution from relict humic‐like dissolved organic matter with sediment depth. Mass balance calculations indicated that the pool of dissolved organic carbon in the SLW water column could be produced in 4.8 to 11.9 yr, which is a time frame similar to that of the lakes’ fill‐drain cycle. Based on these estimates, subglacial lake water discharged at the Siple Coast could supply an average of 5,400% more than the heterotrophic carbon demand within Siple Coast embayments (6.5% for the entire Ross Ice Shelf cavity). Our results suggest that subglacial discharge represents a heretofore unappreciated source of microbially processed dissolved organic carbon and other nutrients to the Southern Ocean. |
format |
Text |
author |
Vick‐Majors, Trista J. Michaud, Alexander B. Skidmore, Mark L. Turetta, Clara Barbante, Carlo Christner, Brent C. |
author_facet |
Vick‐Majors, Trista J. Michaud, Alexander B. Skidmore, Mark L. Turetta, Clara Barbante, Carlo Christner, Brent C. |
author_sort |
Vick‐Majors, Trista J. |
title |
Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment |
title_short |
Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment |
title_full |
Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment |
title_fullStr |
Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment |
title_full_unstemmed |
Biogeochemical connectivity between freshwater ecosystems beneath the West Antarctic ice sheet and the sub‐ice marine environment |
title_sort |
biogeochemical connectivity between freshwater ecosystems beneath the west antarctic ice sheet and the sub‐ice marine environment |
publisher |
Digital Commons @ Michigan Tech |
publishDate |
2020 |
url |
https://digitalcommons.mtu.edu/michigantech-p/1790 https://doi.org/10.1029/2019GB006446 |
long_lat |
ENVELOPE(-83.917,-83.917,-75.917,-75.917) ENVELOPE(-155.000,-155.000,-82.000,-82.000) ENVELOPE(-64.250,-64.250,-84.450,-84.450) ENVELOPE(-145.000,-145.000,-83.667,-83.667) |
geographic |
Antarctic Ross Ice Shelf Siple Siple Coast Southern Ocean The Antarctic West Antarctic Ice Sheet Whillans Whillans Ice Stream |
geographic_facet |
Antarctic Ross Ice Shelf Siple Siple Coast Southern Ocean The Antarctic West Antarctic Ice Sheet Whillans Whillans Ice Stream |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ross Ice Shelf Southern Ocean Whillans Ice Stream |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelf Ross Ice Shelf Southern Ocean Whillans Ice Stream |
op_source |
Michigan Tech Publications |
op_relation |
https://digitalcommons.mtu.edu/michigantech-p/1790 https://doi.org/10.1029/2019GB006446 |
op_doi |
https://doi.org/10.1029/2019GB006446 |
container_title |
Global Biogeochemical Cycles |
container_volume |
34 |
container_issue |
3 |
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1766022516543848448 |