Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry
Seasonal change in surface melt input and spatial controls on the distribution of subglacial water can cause considerable variability in the aqueous chemistry of subglacial waters. Much of this variability has been interpreted in terms of a single variable: water residence time, with slow flow assum...
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ftdoajarticles:oai:doaj.org/article:418707fac7ea489bbd6ea6a24ce9a48f 2023-05-15T16:21:32+02:00 Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry Joseph A. Graly Neil F. Humphrey Kathy J. Licht 2018-11-01T00:00:00Z https://doi.org/10.3389/feart.2018.00195 https://doaj.org/article/418707fac7ea489bbd6ea6a24ce9a48f EN eng Frontiers Media S.A. https://www.frontiersin.org/article/10.3389/feart.2018.00195/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2018.00195 https://doaj.org/article/418707fac7ea489bbd6ea6a24ce9a48f Frontiers in Earth Science, Vol 6 (2018) chemical weathering subglacial hydrology seasonal variation glacial processes hydrochemistry Greenland ice sheet Science Q article 2018 ftdoajarticles https://doi.org/10.3389/feart.2018.00195 2022-12-31T13:52:52Z Seasonal change in surface melt input and spatial controls on the distribution of subglacial water can cause considerable variability in the aqueous chemistry of subglacial waters. Much of this variability has been interpreted in terms of a single variable: water residence time, with slow flow assumed to correlate with greater mineral dissolution and oxidative weathering. We synthesize data from a range of glacier and ice sheet settings to show that this approach does not adequately describe presently available data. Instead, we propose that two independent variables control spatial and seasonal changes in aqueous chemistry in subglacial settings: atmospheric gas abundance and sediment supply abundance. Where atmospheric gases are abundant, carbonation weathering is responsible for most of the subglacial chemical activity; where they become limited, oxidation weathering becomes more dominant. Where freshly comminuted sediment is abundant, easily dissolved minerals, especially calcite, have proportionally more influence on subglacial hydrochemistry; where sediment supply is limited, silicate minerals, and less reactive carbonate minerals will increase in relative influence. In most settings, simple metrics of the abundance of SO42− and Ca2+ in the subglacial waters can characterize these two variables. In the data we synthesize, neither variable consistently correlates to the inferred water residence time, nor do the variables consistently correlate with each other. Spatial data show that point locations and small catchments on the glacial bed differ substantially from the integrated composition found at glacial outlets. The varied response in the subglacial aqueous chemistry to changing water residence times suggests complex control by a broad range of glaciological factors that affect water routing and subglacial sediment generation. Article in Journal/Newspaper glacier Greenland Ice Sheet Directory of Open Access Journals: DOAJ Articles Greenland Frontiers in Earth Science 6 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
chemical weathering subglacial hydrology seasonal variation glacial processes hydrochemistry Greenland ice sheet Science Q |
spellingShingle |
chemical weathering subglacial hydrology seasonal variation glacial processes hydrochemistry Greenland ice sheet Science Q Joseph A. Graly Neil F. Humphrey Kathy J. Licht Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry |
topic_facet |
chemical weathering subglacial hydrology seasonal variation glacial processes hydrochemistry Greenland ice sheet Science Q |
description |
Seasonal change in surface melt input and spatial controls on the distribution of subglacial water can cause considerable variability in the aqueous chemistry of subglacial waters. Much of this variability has been interpreted in terms of a single variable: water residence time, with slow flow assumed to correlate with greater mineral dissolution and oxidative weathering. We synthesize data from a range of glacier and ice sheet settings to show that this approach does not adequately describe presently available data. Instead, we propose that two independent variables control spatial and seasonal changes in aqueous chemistry in subglacial settings: atmospheric gas abundance and sediment supply abundance. Where atmospheric gases are abundant, carbonation weathering is responsible for most of the subglacial chemical activity; where they become limited, oxidation weathering becomes more dominant. Where freshly comminuted sediment is abundant, easily dissolved minerals, especially calcite, have proportionally more influence on subglacial hydrochemistry; where sediment supply is limited, silicate minerals, and less reactive carbonate minerals will increase in relative influence. In most settings, simple metrics of the abundance of SO42− and Ca2+ in the subglacial waters can characterize these two variables. In the data we synthesize, neither variable consistently correlates to the inferred water residence time, nor do the variables consistently correlate with each other. Spatial data show that point locations and small catchments on the glacial bed differ substantially from the integrated composition found at glacial outlets. The varied response in the subglacial aqueous chemistry to changing water residence times suggests complex control by a broad range of glaciological factors that affect water routing and subglacial sediment generation. |
format |
Article in Journal/Newspaper |
author |
Joseph A. Graly Neil F. Humphrey Kathy J. Licht |
author_facet |
Joseph A. Graly Neil F. Humphrey Kathy J. Licht |
author_sort |
Joseph A. Graly |
title |
Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry |
title_short |
Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry |
title_full |
Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry |
title_fullStr |
Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry |
title_full_unstemmed |
Two Metrics Describing the Causes of Seasonal and Spatial Changes in Subglacial Aqueous Chemistry |
title_sort |
two metrics describing the causes of seasonal and spatial changes in subglacial aqueous chemistry |
publisher |
Frontiers Media S.A. |
publishDate |
2018 |
url |
https://doi.org/10.3389/feart.2018.00195 https://doaj.org/article/418707fac7ea489bbd6ea6a24ce9a48f |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland Ice Sheet |
genre_facet |
glacier Greenland Ice Sheet |
op_source |
Frontiers in Earth Science, Vol 6 (2018) |
op_relation |
https://www.frontiersin.org/article/10.3389/feart.2018.00195/full https://doaj.org/toc/2296-6463 2296-6463 doi:10.3389/feart.2018.00195 https://doaj.org/article/418707fac7ea489bbd6ea6a24ce9a48f |
op_doi |
https://doi.org/10.3389/feart.2018.00195 |
container_title |
Frontiers in Earth Science |
container_volume |
6 |
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1766009538565111808 |