Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada
In Siberia and Alaska, permafrost thaw has been associated with significant increases in the delivery of dissolved organic carbon (DOC) to recipient stream ecosystems. Here, we examine the effect of retrogressive thaw slumps (RTSs) on DOC concentration and transport, using data from eight RTS featur...
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ftdoajarticles:oai:doaj.org/article:2f928538a4a94e5b84a246e16fcb30d3 2023-05-15T15:16:43+02:00 Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada C. A. Littlefair S. E. Tank S. V. Kokelj 2017-12-01T00:00:00Z https://doi.org/10.5194/bg-14-5487-2017 https://doaj.org/article/2f928538a4a94e5b84a246e16fcb30d3 EN eng Copernicus Publications https://www.biogeosciences.net/14/5487/2017/bg-14-5487-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-14-5487-2017 1726-4170 1726-4189 https://doaj.org/article/2f928538a4a94e5b84a246e16fcb30d3 Biogeosciences, Vol 14, Pp 5487-5505 (2017) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2017 ftdoajarticles https://doi.org/10.5194/bg-14-5487-2017 2022-12-31T03:33:09Z In Siberia and Alaska, permafrost thaw has been associated with significant increases in the delivery of dissolved organic carbon (DOC) to recipient stream ecosystems. Here, we examine the effect of retrogressive thaw slumps (RTSs) on DOC concentration and transport, using data from eight RTS features on the Peel Plateau, NWT, Canada. Like extensive regions of northwestern Canada, the Peel Plateau is comprised of thick, ice-rich tills that were deposited at the margins of the Laurentide Ice Sheet. RTS features are now widespread in this region, with headwall exposures up to 30 m high and total disturbed areas often exceeding 20 ha. We find that intensive slumping on the Peel Plateau is universally associated with decreasing DOC concentrations downstream of slumps, even though the composition of slump-derived dissolved organic matter (DOM; assessed using specific UV absorbance and slope ratios) is similar to permafrost-derived DOM from other regions. Comparisons of upstream and downstream DOC flux relative to fluxes of total suspended solids suggest that the substantial fine-grained sediments released by RTS features may sequester DOC. Runoff obtained directly from slump rill water, above entry into recipient streams, indicates that the deepest RTS features, which thaw the greatest extent of buried, Pleistocene-aged glacial tills, release low-concentration DOC when compared to paired upstream, undisturbed locations, while shallower features, with exposures that are more limited to a relict Holocene active layer, have within-slump DOC concentrations more similar to upstream sites. Finally, fine-scale work at a single RTS site indicates that temperature and precipitation serve as primary environmental controls on above-slump and below-slump DOC flux, but it also shows that the relationship between climatic parameters and DOC flux is complex for these dynamic thermokarst features. These results demonstrate that we should expect clear variation in thermokarst-associated DOC mobilization across Arctic regions. ... Article in Journal/Newspaper Arctic Ice Ice Sheet permafrost Thermokarst Alaska Siberia Directory of Open Access Journals: DOAJ Articles Arctic Canada Biogeosciences 14 23 5487 5505 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 C. A. Littlefair S. E. Tank S. V. Kokelj Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
In Siberia and Alaska, permafrost thaw has been associated with significant increases in the delivery of dissolved organic carbon (DOC) to recipient stream ecosystems. Here, we examine the effect of retrogressive thaw slumps (RTSs) on DOC concentration and transport, using data from eight RTS features on the Peel Plateau, NWT, Canada. Like extensive regions of northwestern Canada, the Peel Plateau is comprised of thick, ice-rich tills that were deposited at the margins of the Laurentide Ice Sheet. RTS features are now widespread in this region, with headwall exposures up to 30 m high and total disturbed areas often exceeding 20 ha. We find that intensive slumping on the Peel Plateau is universally associated with decreasing DOC concentrations downstream of slumps, even though the composition of slump-derived dissolved organic matter (DOM; assessed using specific UV absorbance and slope ratios) is similar to permafrost-derived DOM from other regions. Comparisons of upstream and downstream DOC flux relative to fluxes of total suspended solids suggest that the substantial fine-grained sediments released by RTS features may sequester DOC. Runoff obtained directly from slump rill water, above entry into recipient streams, indicates that the deepest RTS features, which thaw the greatest extent of buried, Pleistocene-aged glacial tills, release low-concentration DOC when compared to paired upstream, undisturbed locations, while shallower features, with exposures that are more limited to a relict Holocene active layer, have within-slump DOC concentrations more similar to upstream sites. Finally, fine-scale work at a single RTS site indicates that temperature and precipitation serve as primary environmental controls on above-slump and below-slump DOC flux, but it also shows that the relationship between climatic parameters and DOC flux is complex for these dynamic thermokarst features. These results demonstrate that we should expect clear variation in thermokarst-associated DOC mobilization across Arctic regions. ... |
format |
Article in Journal/Newspaper |
author |
C. A. Littlefair S. E. Tank S. V. Kokelj |
author_facet |
C. A. Littlefair S. E. Tank S. V. Kokelj |
author_sort |
C. A. Littlefair |
title |
Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada |
title_short |
Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada |
title_full |
Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada |
title_fullStr |
Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada |
title_full_unstemmed |
Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada |
title_sort |
retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the peel plateau, nwt, canada |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/bg-14-5487-2017 https://doaj.org/article/2f928538a4a94e5b84a246e16fcb30d3 |
geographic |
Arctic Canada |
geographic_facet |
Arctic Canada |
genre |
Arctic Ice Ice Sheet permafrost Thermokarst Alaska Siberia |
genre_facet |
Arctic Ice Ice Sheet permafrost Thermokarst Alaska Siberia |
op_source |
Biogeosciences, Vol 14, Pp 5487-5505 (2017) |
op_relation |
https://www.biogeosciences.net/14/5487/2017/bg-14-5487-2017.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 doi:10.5194/bg-14-5487-2017 1726-4170 1726-4189 https://doaj.org/article/2f928538a4a94e5b84a246e16fcb30d3 |
op_doi |
https://doi.org/10.5194/bg-14-5487-2017 |
container_title |
Biogeosciences |
container_volume |
14 |
container_issue |
23 |
container_start_page |
5487 |
op_container_end_page |
5505 |
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1766347013584060416 |