Carbon dating reveals a seasonal progression in the source of particulate organic carbon exported from the Greenland Ice Sheet

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Version: Final published version
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Serval ID
serval:BIB_354EF9AFF86C
Type
Article: article from journal or magazin.
Collection
Publications
Title
Carbon dating reveals a seasonal progression in the source of particulate organic carbon exported from the Greenland Ice Sheet
Journal
Geophysical Research Letters
Author(s)
Kohler T. J., Žárský J. D., Yde J. C., Lamarche-Gagnon G., Hawkings J. R., Tedstone A. J., Wadham J. L., Box J. E., Beaton A. D., Stibal M.
ISSN
0094-8276
1944-8007
Publication state
Published
Issued date
28/06/2017
Peer-reviewed
Oui
Volume
44
Number
12
Pages
6209-6217
Language
english
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.
Keywords
meltwater export, particulate organic carbon, glacial hydrology, subglacial drainage system, Kangerlussuaq, Leverett Glacier
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Create date
29/08/2024 10:03
Last modification date
25/11/2024 16:39
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