Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering
Soils in ice-free areas in Antarctica are recognized for their high salt concentrations and persistent arid conditions. While previous studies have investigated the distribution of salts and potential sources in the McMurdo Dry Valleys, logistical constraints have limited our investigation and under...
Published in: | Frontiers in Earth Science |
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ftdoajarticles:oai:doaj.org/article:b0649ba6f5484789949e1845ef94c0cb 2023-05-15T14:04:31+02:00 Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering Melisa A. Diaz Jianghanyang Li Greg Michalski Thomas H. Darrah Byron J. Adams Diana H. Wall Ian D. Hogg Noah Fierer Susan A. Welch Christopher B. Gardner W. Berry Lyons 2020-08-01T00:00:00Z https://doi.org/10.3389/feart.2020.00341 https://doaj.org/article/b0649ba6f5484789949e1845ef94c0cb EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/feart.2020.00341/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2020.00341 https://doaj.org/article/b0649ba6f5484789949e1845ef94c0cb Frontiers in Earth Science, Vol 8 (2020) Antarctica geochemistry salts stable isotopes nitrate sulfate Science Q article 2020 ftdoajarticles https://doi.org/10.3389/feart.2020.00341 2022-12-31T03:04:06Z Soils in ice-free areas in Antarctica are recognized for their high salt concentrations and persistent arid conditions. While previous studies have investigated the distribution of salts and potential sources in the McMurdo Dry Valleys, logistical constraints have limited our investigation and understanding of salt dynamics within the Transantarctic Mountains. We focused on the Shackleton Glacier (85° S, 176° W), a major outlet glacier of the East Antarctic Ice Sheet located in the Central Transantarctic Mountains (CTAM), and collected surface soil samples from 10 ice-free areas. Concentrations of water-soluble nitrate (NO3–) and sulfate (SO42–) ranged from <0.2 to ∼150 μmol g–1 and <0.02 to ∼450 μmol g–1, respectively. In general, salt concentrations increased with distance inland and with elevation. However, concentrations also increased with distance from current glacial ice position. To understand the source and formation of these salts, we measured the stable isotopes of dissolved water-soluble NO3– and SO42–, and soil carbonate (HCO3 + CO3). δ15N-NO3 values ranged from −47.8 to 20.4‰ and, while all Δ17O-NO3 values are positive, they ranged from 15.7 to 45.9‰. δ34S-SO4 and δ18O-SO4 values ranged from 12.5 and 17.9‰ and −14.5 to −7.1‰, respectively. Total inorganic carbon isotopes in bulk soil samples ranged from 0.2 to 8.5‰ for δ13C and −38.8 to −9.6‰ for δ18O. A simple mixing model indicates that NO3– is primarily derived from the troposphere (0–70%) and stratosphere (30–100%). SO42– is primarily derived from secondary atmospheric sulfate (SAS) by the oxidation of reduced sulfur gases and compounds in the atmosphere by H2O2, carbonyl sulfide (COS), and ozone. Calcite and perhaps nahcolite (NaHCO3) are formed through both slow and rapid freezing and/or the evaporation/sublimation of HCO3 + CO3-rich fluids. Our results indicate that the origins of salts from ice-free areas within the CTAM represent a complex interplay of atmospheric deposition, chemical weathering, and post-depositional processes ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet McMurdo Dry Valleys Shackleton Glacier Directory of Open Access Journals: DOAJ Articles Antarctic East Antarctic Ice Sheet McMurdo Dry Valleys Shackleton Shackleton Glacier ENVELOPE(-37.200,-37.200,-54.133,-54.133) Transantarctic Mountains Frontiers in Earth Science 8 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
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language |
English |
topic |
Antarctica geochemistry salts stable isotopes nitrate sulfate Science Q |
spellingShingle |
Antarctica geochemistry salts stable isotopes nitrate sulfate Science Q Melisa A. Diaz Jianghanyang Li Greg Michalski Thomas H. Darrah Byron J. Adams Diana H. Wall Ian D. Hogg Noah Fierer Susan A. Welch Christopher B. Gardner W. Berry Lyons Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering |
topic_facet |
Antarctica geochemistry salts stable isotopes nitrate sulfate Science Q |
description |
Soils in ice-free areas in Antarctica are recognized for their high salt concentrations and persistent arid conditions. While previous studies have investigated the distribution of salts and potential sources in the McMurdo Dry Valleys, logistical constraints have limited our investigation and understanding of salt dynamics within the Transantarctic Mountains. We focused on the Shackleton Glacier (85° S, 176° W), a major outlet glacier of the East Antarctic Ice Sheet located in the Central Transantarctic Mountains (CTAM), and collected surface soil samples from 10 ice-free areas. Concentrations of water-soluble nitrate (NO3–) and sulfate (SO42–) ranged from <0.2 to ∼150 μmol g–1 and <0.02 to ∼450 μmol g–1, respectively. In general, salt concentrations increased with distance inland and with elevation. However, concentrations also increased with distance from current glacial ice position. To understand the source and formation of these salts, we measured the stable isotopes of dissolved water-soluble NO3– and SO42–, and soil carbonate (HCO3 + CO3). δ15N-NO3 values ranged from −47.8 to 20.4‰ and, while all Δ17O-NO3 values are positive, they ranged from 15.7 to 45.9‰. δ34S-SO4 and δ18O-SO4 values ranged from 12.5 and 17.9‰ and −14.5 to −7.1‰, respectively. Total inorganic carbon isotopes in bulk soil samples ranged from 0.2 to 8.5‰ for δ13C and −38.8 to −9.6‰ for δ18O. A simple mixing model indicates that NO3– is primarily derived from the troposphere (0–70%) and stratosphere (30–100%). SO42– is primarily derived from secondary atmospheric sulfate (SAS) by the oxidation of reduced sulfur gases and compounds in the atmosphere by H2O2, carbonyl sulfide (COS), and ozone. Calcite and perhaps nahcolite (NaHCO3) are formed through both slow and rapid freezing and/or the evaporation/sublimation of HCO3 + CO3-rich fluids. Our results indicate that the origins of salts from ice-free areas within the CTAM represent a complex interplay of atmospheric deposition, chemical weathering, and post-depositional processes ... |
format |
Article in Journal/Newspaper |
author |
Melisa A. Diaz Jianghanyang Li Greg Michalski Thomas H. Darrah Byron J. Adams Diana H. Wall Ian D. Hogg Noah Fierer Susan A. Welch Christopher B. Gardner W. Berry Lyons |
author_facet |
Melisa A. Diaz Jianghanyang Li Greg Michalski Thomas H. Darrah Byron J. Adams Diana H. Wall Ian D. Hogg Noah Fierer Susan A. Welch Christopher B. Gardner W. Berry Lyons |
author_sort |
Melisa A. Diaz |
title |
Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering |
title_short |
Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering |
title_full |
Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering |
title_fullStr |
Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering |
title_full_unstemmed |
Stable Isotopes of Nitrate, Sulfate, and Carbonate in Soils From the Transantarctic Mountains, Antarctica: A Record of Atmospheric Deposition and Chemical Weathering |
title_sort |
stable isotopes of nitrate, sulfate, and carbonate in soils from the transantarctic mountains, antarctica: a record of atmospheric deposition and chemical weathering |
publisher |
Frontiers Media S.A. |
publishDate |
2020 |
url |
https://doi.org/10.3389/feart.2020.00341 https://doaj.org/article/b0649ba6f5484789949e1845ef94c0cb |
long_lat |
ENVELOPE(-37.200,-37.200,-54.133,-54.133) |
geographic |
Antarctic East Antarctic Ice Sheet McMurdo Dry Valleys Shackleton Shackleton Glacier Transantarctic Mountains |
geographic_facet |
Antarctic East Antarctic Ice Sheet McMurdo Dry Valleys Shackleton Shackleton Glacier Transantarctic Mountains |
genre |
Antarc* Antarctic Antarctica Ice Sheet McMurdo Dry Valleys Shackleton Glacier |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet McMurdo Dry Valleys Shackleton Glacier |
op_source |
Frontiers in Earth Science, Vol 8 (2020) |
op_relation |
https://www.frontiersin.org/article/10.3389/feart.2020.00341/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2020.00341 https://doaj.org/article/b0649ba6f5484789949e1845ef94c0cb |
op_doi |
https://doi.org/10.3389/feart.2020.00341 |
container_title |
Frontiers in Earth Science |
container_volume |
8 |
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1766275692947832832 |