Carbon dating reveals a seasonal progression in the source of particulate organic carbon exported from the Greenland Ice Sheet
Carbon dating reveals a seasonal progression in the source of particulate organic carbon exported from the Greenland Ice Sheet
Surface melt from the Greenland Ice Sheet (GrIS) collects particulate organic carbon (POC) as it drains into subglacial environments and transports it downstream where it serves as a microbial substrate. We hypothesized that older POC is entrained by meltwaters as the subglacial drainage network expands upglacier over the summer. To test this, POC samples were collected from a meltwater river exiting the GrIS over an ablation season and 14C dated. Resulting values were compared with meltwater hydrochemistry and satellite observations of the catchment area. We found that POC ages increased from ~5000 to ~9000 years B.P. until peak discharge and catchment size. Afterward, significant fluctuations in POC age were observed, interpreted to result from periods of high and low subglacial hydrological pressure and sediment supply and subsequent exhaustion. These observations suggest a seasonal progression in the source of POC exported from the GrIS and provide evidence for a seasonally evolving subglacial drainage system.
6209–6217
Kohler, T.J.
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Žárský, J.D.
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Yde, J.C.
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Lamarche-Gagnon, G.
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Hawkings, J.R.
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Tedstone, A.J.
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Wadham, J.L.
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Box, J.E.
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Beaton, A.D.
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28 June 2017
Kohler, T.J.
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Žárský, J.D.
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Yde, J.C.
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Lamarche-Gagnon, G.
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Hawkings, J.R.
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Tedstone, A.J.
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Wadham, J.L.
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Box, J.E.
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Beaton, A.D.
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Kohler, T.J., Žárský, J.D., Yde, J.C., Lamarche-Gagnon, G., Hawkings, J.R., Tedstone, A.J., Wadham, J.L., Box, J.E. and Beaton, A.D.
(2017)
Carbon dating reveals a seasonal progression in the source of particulate organic carbon exported from the Greenland Ice Sheet.
Geophysical Research Letters, 44 (12), .
(doi:10.1002/2017GL073219).
Abstract
Surface melt from the Greenland Ice Sheet (GrIS) collects particulate organic carbon (POC) as it drains into subglacial environments and transports it downstream where it serves as a microbial substrate. We hypothesized that older POC is entrained by meltwaters as the subglacial drainage network expands upglacier over the summer. To test this, POC samples were collected from a meltwater river exiting the GrIS over an ablation season and 14C dated. Resulting values were compared with meltwater hydrochemistry and satellite observations of the catchment area. We found that POC ages increased from ~5000 to ~9000 years B.P. until peak discharge and catchment size. Afterward, significant fluctuations in POC age were observed, interpreted to result from periods of high and low subglacial hydrological pressure and sediment supply and subsequent exhaustion. These observations suggest a seasonal progression in the source of POC exported from the GrIS and provide evidence for a seasonally evolving subglacial drainage system.
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Kohler_et_al-2017-Geophysical_Research_Letters
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Accepted/In Press date: 5 June 2017
e-pub ahead of print date: 22 June 2017
Published date: 28 June 2017
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Local EPrints ID: 413334
URI: http://eprints.soton.ac.uk/id/eprint/413334
ISSN: 0094-8276
PURE UUID: 9f00e2a3-913e-4735-816d-0b3252a7a711
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Date deposited: 22 Aug 2017 16:31
Last modified: 16 Mar 2024 05:40
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Contributors
Author:
T.J. Kohler
Author:
J.D. Žárský
Author:
J.C. Yde
Author:
G. Lamarche-Gagnon
Author:
J.R. Hawkings
Author:
A.J. Tedstone
Author:
J.L. Wadham
Author:
J.E. Box
Author:
A.D. Beaton
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