Enhanced trace element mobilization by Earth’s ice sheets
Trace elements sustain biological productivity, yet the significance of trace element mobilization and export in subglacial runoff from ice sheets is poorly constrained at present. Here, we present size-fractionated (0.02, 0.22, and 0.45 µm) concentrations of trace elements in subglacial waters from...
Published in: | Proceedings of the National Academy of Sciences |
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5004276 2023-05-15T14:02:24+02:00 Enhanced trace element mobilization by Earth’s ice sheets Hawkings, J. Skidmore, M. Wadham, J. Priscu, J. Morton, P. Hatton, J. Gardner, C. Kohler, T. Stibal, M. Bagshaw, E. Steigmeyer, A. Barker, J. Dore, J. Lyons, W. Tranter, M. Spencer, R. 2020 application/pdf https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276_6/component/file_5005921/5004276.pdf unknown info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.2014378117 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276_6/component/file_5005921/5004276.pdf info:eu-repo/semantics/openAccess Proceedings of the National Academy of Sciences of the United States of America (PNAS) info:eu-repo/semantics/article 2020 ftgfzpotsdam https://doi.org/10.1073/pnas.2014378117 2022-09-14T05:57:46Z Trace elements sustain biological productivity, yet the significance of trace element mobilization and export in subglacial runoff from ice sheets is poorly constrained at present. Here, we present size-fractionated (0.02, 0.22, and 0.45 µm) concentrations of trace elements in subglacial waters from the Greenland Ice Sheet (GrIS) and the Antarctic Ice Sheet (AIS). Concentrations of immobile trace elements (e.g., Al, Fe, Ti) far exceed global riverine and open ocean mean values and highlight the importance of subglacial aluminosilicate mineral weathering and lack of retention of these species in sediments. Concentrations are higher from the AIS than the GrIS, highlighting the geochemical consequences of prolonged water residence times and hydrological isolation that characterize the former. The enrichment of trace elements (e.g., Co, Fe, Mn, and Zn) in subglacial meltwaters compared with seawater and typical riverine systems, together with the likely sensitivity to future ice sheet melting, suggests that their export in glacial runoff is likely to be important for biological productivity. For example, our dissolved Fe concentration (20,900 nM) and associated flux values (1.4 Gmol y−1) from AIS to the Fe-deplete Southern Ocean exceed most previous estimates by an order of magnitude. The ultimate fate of these micronutrients will depend on the reactivity of the dominant colloidal size fraction (likely controlled by nanoparticulate Al and Fe oxyhydroxide minerals) and estuarine processing. We contend that ice sheets create highly geochemically reactive particulates in subglacial environments, which play a key role in trace elemental cycles, with potentially important consequences for global carbon cycling. Article in Journal/Newspaper Antarc* Antarctic Greenland Ice Sheet Southern Ocean GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic Greenland Southern Ocean The Antarctic Proceedings of the National Academy of Sciences 117 50 31648 31659 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
unknown |
description |
Trace elements sustain biological productivity, yet the significance of trace element mobilization and export in subglacial runoff from ice sheets is poorly constrained at present. Here, we present size-fractionated (0.02, 0.22, and 0.45 µm) concentrations of trace elements in subglacial waters from the Greenland Ice Sheet (GrIS) and the Antarctic Ice Sheet (AIS). Concentrations of immobile trace elements (e.g., Al, Fe, Ti) far exceed global riverine and open ocean mean values and highlight the importance of subglacial aluminosilicate mineral weathering and lack of retention of these species in sediments. Concentrations are higher from the AIS than the GrIS, highlighting the geochemical consequences of prolonged water residence times and hydrological isolation that characterize the former. The enrichment of trace elements (e.g., Co, Fe, Mn, and Zn) in subglacial meltwaters compared with seawater and typical riverine systems, together with the likely sensitivity to future ice sheet melting, suggests that their export in glacial runoff is likely to be important for biological productivity. For example, our dissolved Fe concentration (20,900 nM) and associated flux values (1.4 Gmol y−1) from AIS to the Fe-deplete Southern Ocean exceed most previous estimates by an order of magnitude. The ultimate fate of these micronutrients will depend on the reactivity of the dominant colloidal size fraction (likely controlled by nanoparticulate Al and Fe oxyhydroxide minerals) and estuarine processing. We contend that ice sheets create highly geochemically reactive particulates in subglacial environments, which play a key role in trace elemental cycles, with potentially important consequences for global carbon cycling. |
format |
Article in Journal/Newspaper |
author |
Hawkings, J. Skidmore, M. Wadham, J. Priscu, J. Morton, P. Hatton, J. Gardner, C. Kohler, T. Stibal, M. Bagshaw, E. Steigmeyer, A. Barker, J. Dore, J. Lyons, W. Tranter, M. Spencer, R. |
spellingShingle |
Hawkings, J. Skidmore, M. Wadham, J. Priscu, J. Morton, P. Hatton, J. Gardner, C. Kohler, T. Stibal, M. Bagshaw, E. Steigmeyer, A. Barker, J. Dore, J. Lyons, W. Tranter, M. Spencer, R. Enhanced trace element mobilization by Earth’s ice sheets |
author_facet |
Hawkings, J. Skidmore, M. Wadham, J. Priscu, J. Morton, P. Hatton, J. Gardner, C. Kohler, T. Stibal, M. Bagshaw, E. Steigmeyer, A. Barker, J. Dore, J. Lyons, W. Tranter, M. Spencer, R. |
author_sort |
Hawkings, J. |
title |
Enhanced trace element mobilization by Earth’s ice sheets |
title_short |
Enhanced trace element mobilization by Earth’s ice sheets |
title_full |
Enhanced trace element mobilization by Earth’s ice sheets |
title_fullStr |
Enhanced trace element mobilization by Earth’s ice sheets |
title_full_unstemmed |
Enhanced trace element mobilization by Earth’s ice sheets |
title_sort |
enhanced trace element mobilization by earth’s ice sheets |
publishDate |
2020 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276_6/component/file_5005921/5004276.pdf |
geographic |
Antarctic Greenland Southern Ocean The Antarctic |
geographic_facet |
Antarctic Greenland Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Greenland Ice Sheet Southern Ocean |
genre_facet |
Antarc* Antarctic Greenland Ice Sheet Southern Ocean |
op_source |
Proceedings of the National Academy of Sciences of the United States of America (PNAS) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1073/pnas.2014378117 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004276_6/component/file_5005921/5004276.pdf |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1073/pnas.2014378117 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
117 |
container_issue |
50 |
container_start_page |
31648 |
op_container_end_page |
31659 |
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1766272660969357312 |