Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland
The Greenland Ice Sheet is losing mass at a remarkable rate as a result of climatic warming. This mass loss coincides with the export of dissolved organic matter (DOM) in glacial meltwaters. However, little is known about how the source and composition of exported DOM changes over the melt season, w...
Published in: | Journal of Geophysical Research: Biogeosciences |
---|---|
Main Authors: | , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
2020
|
Subjects: | |
Online Access: | https://gfzpublic.gfz-potsdam.de/pubman/item/item_5002088 |
id |
ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5002088 |
---|---|
record_format |
openpolar |
spelling |
ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5002088 2023-05-15T16:21:04+02:00 Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland Kellerman, A. Hawkings, J. Wadham, J. Kohler, T. Stibal, M. Grater, E. Marshall, M. Hatton, J. Beaton, A. Spencer, R. 2020 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5002088 unknown info:eu-repo/semantics/altIdentifier/doi/10.1029/2019JG005161 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5002088 Journal of Geophysical Research: Biogeosciences info:eu-repo/semantics/article 2020 ftgfzpotsdam https://doi.org/10.1029/2019JG005161 2022-09-14T05:57:34Z The Greenland Ice Sheet is losing mass at a remarkable rate as a result of climatic warming. This mass loss coincides with the export of dissolved organic matter (DOM) in glacial meltwaters. However, little is known about how the source and composition of exported DOM changes over the melt season, which is key for understanding its fate in downstream ecosystems. Over the 2015 ablation season, we sampled the outflow of Leverett Glacier, a large land‐terminating glacier of the Greenland Ice Sheet. Dissolved organic carbon (DOC) concentrations and DOM fluorescence were analyzed to assess the evolution of DOM sources over the course of the melt season. DOC concentrations and red‐shifted fluorescence were highly associated (R 2 > 0.95) and suggest terrestrial inputs from overridden soils dominated DOM early season inputs before progressive dilution with increasing discharge. During the outburst period, supraglacial drainage events disrupted the subglacial drainage system and introduced dominant protein‐like fluorescence signatures not observed in basal flow. These results suggest that subglacial hydrology and changing water sources influence exported DOC concentration and DOM composition, and these sources were differentiated using fluorescence characteristics. Red‐shifted fluorescence components were robust proxies for DOC concentration. Finally, the majority of DOM flux, which occurs during the outburst and postoutburst periods, was characterized by protein‐like fluorescence from supraglacial and potentially subglacial microbial sources. As protein‐like fluorescence is linked to the bioavailability of DOM, the observed changes likely reflect seasonal variations in the impact of glacial inputs on secondary production in downstream ecosystems due to shifting hydrologic regimes. Article in Journal/Newspaper glacier Greenland Ice Sheet Leverett Glacier GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Greenland Leverett Glacier ENVELOPE(-147.583,-147.583,-85.633,-85.633) Journal of Geophysical Research: Biogeosciences 125 4 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
unknown |
description |
The Greenland Ice Sheet is losing mass at a remarkable rate as a result of climatic warming. This mass loss coincides with the export of dissolved organic matter (DOM) in glacial meltwaters. However, little is known about how the source and composition of exported DOM changes over the melt season, which is key for understanding its fate in downstream ecosystems. Over the 2015 ablation season, we sampled the outflow of Leverett Glacier, a large land‐terminating glacier of the Greenland Ice Sheet. Dissolved organic carbon (DOC) concentrations and DOM fluorescence were analyzed to assess the evolution of DOM sources over the course of the melt season. DOC concentrations and red‐shifted fluorescence were highly associated (R 2 > 0.95) and suggest terrestrial inputs from overridden soils dominated DOM early season inputs before progressive dilution with increasing discharge. During the outburst period, supraglacial drainage events disrupted the subglacial drainage system and introduced dominant protein‐like fluorescence signatures not observed in basal flow. These results suggest that subglacial hydrology and changing water sources influence exported DOC concentration and DOM composition, and these sources were differentiated using fluorescence characteristics. Red‐shifted fluorescence components were robust proxies for DOC concentration. Finally, the majority of DOM flux, which occurs during the outburst and postoutburst periods, was characterized by protein‐like fluorescence from supraglacial and potentially subglacial microbial sources. As protein‐like fluorescence is linked to the bioavailability of DOM, the observed changes likely reflect seasonal variations in the impact of glacial inputs on secondary production in downstream ecosystems due to shifting hydrologic regimes. |
format |
Article in Journal/Newspaper |
author |
Kellerman, A. Hawkings, J. Wadham, J. Kohler, T. Stibal, M. Grater, E. Marshall, M. Hatton, J. Beaton, A. Spencer, R. |
spellingShingle |
Kellerman, A. Hawkings, J. Wadham, J. Kohler, T. Stibal, M. Grater, E. Marshall, M. Hatton, J. Beaton, A. Spencer, R. Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland |
author_facet |
Kellerman, A. Hawkings, J. Wadham, J. Kohler, T. Stibal, M. Grater, E. Marshall, M. Hatton, J. Beaton, A. Spencer, R. |
author_sort |
Kellerman, A. |
title |
Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland |
title_short |
Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland |
title_full |
Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland |
title_fullStr |
Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland |
title_full_unstemmed |
Glacier Outflow Dissolved Organic Matter as a Window Into Seasonally Changing Carbon Sources: Leverett Glacier, Greenland |
title_sort |
glacier outflow dissolved organic matter as a window into seasonally changing carbon sources: leverett glacier, greenland |
publishDate |
2020 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5002088 |
long_lat |
ENVELOPE(-147.583,-147.583,-85.633,-85.633) |
geographic |
Greenland Leverett Glacier |
geographic_facet |
Greenland Leverett Glacier |
genre |
glacier Greenland Ice Sheet Leverett Glacier |
genre_facet |
glacier Greenland Ice Sheet Leverett Glacier |
op_source |
Journal of Geophysical Research: Biogeosciences |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2019JG005161 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5002088 |
op_doi |
https://doi.org/10.1029/2019JG005161 |
container_title |
Journal of Geophysical Research: Biogeosciences |
container_volume |
125 |
container_issue |
4 |
_version_ |
1766009083595325440 |