Greenland Ice Sheet exports labile organic carbon to the Arctic oceans
Runoff from small glacier systems contains dissolved organic carbon (DOC) rich in protein-like, low molecular weight (LMW) compounds, designating glaciers as an important source of bioavailable carbon for downstream heterotrophic activity. Fluxes of DOC and particulate organic carbon (POC) exported...
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European Geosciences Union
2014
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Online Access: | https://doi.org/10.5194/bg-11-4015-2014 https://nottingham-repository.worktribe.com/file/731589/1/FINAL-VERSION-bg-11-4015-2014.pdf https://nottingham-repository.worktribe.com/output/731589 |
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ftunnottinghamrr:oai:nottingham-repository.worktribe.com:731589 2023-05-15T15:00:35+02:00 Greenland Ice Sheet exports labile organic carbon to the Arctic oceans Lawson, Emily C. Wadham, Jemma L. Tranter, Martyn Stibal, Marek Lis, Greg P. Butler, Catriona E.H. Laybourn-Parry, Johanna Nienow, Peter Chandler, David Dewsbury, Paul 2014-07-31 https://doi.org/10.5194/bg-11-4015-2014 https://nottingham-repository.worktribe.com/file/731589/1/FINAL-VERSION-bg-11-4015-2014.pdf https://nottingham-repository.worktribe.com/output/731589 unknown European Geosciences Union https://nottingham-repository.worktribe.com/output/731589 Biogeosciences Volume 11 Issue 14 doi:https://doi.org/10.5194/bg-11-4015-2014 https://nottingham-repository.worktribe.com/file/731589/1/FINAL-VERSION-bg-11-4015-2014.pdf 1726-4170 doi:10.5194/bg-11-4015-2014 openAccess Glacier carbon bioavailable microbes Greenland Ice Sheet Journal Article 2014 ftunnottinghamrr https://doi.org/10.5194/bg-11-4015-2014 2022-10-13T22:08:12Z Runoff from small glacier systems contains dissolved organic carbon (DOC) rich in protein-like, low molecular weight (LMW) compounds, designating glaciers as an important source of bioavailable carbon for downstream heterotrophic activity. Fluxes of DOC and particulate organic carbon (POC) exported from large Greenland catchments, however, remain unquantified, despite the Greenland Ice Sheet (GrIS) being the largest source of global glacial runoff (ca. 400 km3 yr−1). We report high and episodic fluxes of POC and DOC from a large (> 600 km2) GrIS catchment during contrasting melt seasons. POC dominates organic carbon (OC) export (70–89% on average), is sourced from the ice sheet bed, and contains a significant bioreactive component (9% carbohydrates). A major source of the “bioavailable” (free carbohydrate) LMW–DOC fraction is microbial activity on the ice sheet surface, with some further addition of LMW–DOC to meltwaters by biogeochemical processes at the ice sheet bed. The bioavailability of the exported DOC (26–53%) to downstream marine microorganisms is similar to that reported from other glacial watersheds. Annual fluxes of DOC and free carbohydrates during two melt seasons were similar, despite the approximately two-fold difference in runoff fluxes, suggesting production-limited DOC sources. POC fluxes were also insensitive to an increase in seasonal runoff volumes, indicating a supply limitation in suspended sediment in runoff. Scaled to the GrIS, the combined DOC (0.13–0.17 TgC yr−1 (±13 %)) and POC fluxes (mean = 0.36–1.52 TgC yr−1 (±14 %)) are of a similar order of magnitude to a large Arctic river system, and hence may represent an important OC source to the near-coastal North Atlantic, Greenland and Labrador seas. Article in Journal/Newspaper Arctic glacier Greenland Ice Sheet North Atlantic University of Nottingham: Repository@Nottingham Arctic Greenland Biogeosciences 11 14 4015 4028 |
institution |
Open Polar |
collection |
University of Nottingham: Repository@Nottingham |
op_collection_id |
ftunnottinghamrr |
language |
unknown |
topic |
Glacier carbon bioavailable microbes Greenland Ice Sheet |
spellingShingle |
Glacier carbon bioavailable microbes Greenland Ice Sheet Lawson, Emily C. Wadham, Jemma L. Tranter, Martyn Stibal, Marek Lis, Greg P. Butler, Catriona E.H. Laybourn-Parry, Johanna Nienow, Peter Chandler, David Dewsbury, Paul Greenland Ice Sheet exports labile organic carbon to the Arctic oceans |
topic_facet |
Glacier carbon bioavailable microbes Greenland Ice Sheet |
description |
Runoff from small glacier systems contains dissolved organic carbon (DOC) rich in protein-like, low molecular weight (LMW) compounds, designating glaciers as an important source of bioavailable carbon for downstream heterotrophic activity. Fluxes of DOC and particulate organic carbon (POC) exported from large Greenland catchments, however, remain unquantified, despite the Greenland Ice Sheet (GrIS) being the largest source of global glacial runoff (ca. 400 km3 yr−1). We report high and episodic fluxes of POC and DOC from a large (> 600 km2) GrIS catchment during contrasting melt seasons. POC dominates organic carbon (OC) export (70–89% on average), is sourced from the ice sheet bed, and contains a significant bioreactive component (9% carbohydrates). A major source of the “bioavailable” (free carbohydrate) LMW–DOC fraction is microbial activity on the ice sheet surface, with some further addition of LMW–DOC to meltwaters by biogeochemical processes at the ice sheet bed. The bioavailability of the exported DOC (26–53%) to downstream marine microorganisms is similar to that reported from other glacial watersheds. Annual fluxes of DOC and free carbohydrates during two melt seasons were similar, despite the approximately two-fold difference in runoff fluxes, suggesting production-limited DOC sources. POC fluxes were also insensitive to an increase in seasonal runoff volumes, indicating a supply limitation in suspended sediment in runoff. Scaled to the GrIS, the combined DOC (0.13–0.17 TgC yr−1 (±13 %)) and POC fluxes (mean = 0.36–1.52 TgC yr−1 (±14 %)) are of a similar order of magnitude to a large Arctic river system, and hence may represent an important OC source to the near-coastal North Atlantic, Greenland and Labrador seas. |
format |
Article in Journal/Newspaper |
author |
Lawson, Emily C. Wadham, Jemma L. Tranter, Martyn Stibal, Marek Lis, Greg P. Butler, Catriona E.H. Laybourn-Parry, Johanna Nienow, Peter Chandler, David Dewsbury, Paul |
author_facet |
Lawson, Emily C. Wadham, Jemma L. Tranter, Martyn Stibal, Marek Lis, Greg P. Butler, Catriona E.H. Laybourn-Parry, Johanna Nienow, Peter Chandler, David Dewsbury, Paul |
author_sort |
Lawson, Emily C. |
title |
Greenland Ice Sheet exports labile organic carbon to the Arctic oceans |
title_short |
Greenland Ice Sheet exports labile organic carbon to the Arctic oceans |
title_full |
Greenland Ice Sheet exports labile organic carbon to the Arctic oceans |
title_fullStr |
Greenland Ice Sheet exports labile organic carbon to the Arctic oceans |
title_full_unstemmed |
Greenland Ice Sheet exports labile organic carbon to the Arctic oceans |
title_sort |
greenland ice sheet exports labile organic carbon to the arctic oceans |
publisher |
European Geosciences Union |
publishDate |
2014 |
url |
https://doi.org/10.5194/bg-11-4015-2014 https://nottingham-repository.worktribe.com/file/731589/1/FINAL-VERSION-bg-11-4015-2014.pdf https://nottingham-repository.worktribe.com/output/731589 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic glacier Greenland Ice Sheet North Atlantic |
genre_facet |
Arctic glacier Greenland Ice Sheet North Atlantic |
op_relation |
https://nottingham-repository.worktribe.com/output/731589 Biogeosciences Volume 11 Issue 14 doi:https://doi.org/10.5194/bg-11-4015-2014 https://nottingham-repository.worktribe.com/file/731589/1/FINAL-VERSION-bg-11-4015-2014.pdf 1726-4170 doi:10.5194/bg-11-4015-2014 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.5194/bg-11-4015-2014 |
container_title |
Biogeosciences |
container_volume |
11 |
container_issue |
14 |
container_start_page |
4015 |
op_container_end_page |
4028 |
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1766332671429967872 |