The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem
Soil carbon stored in high-latitude permafrost landscapes is threatened by warming and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Thermokarst and permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, are...
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2016
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ftdoajarticles:oai:doaj.org/article:f25741ccc8784fe9bfaf4e0b34c2ab03 2023-05-15T14:58:10+02:00 The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem A. E. Cassidy A. Christen G. H. R. Henry 2016-04-01T00:00:00Z https://doi.org/10.5194/bg-13-2291-2016 https://doaj.org/article/f25741ccc8784fe9bfaf4e0b34c2ab03 EN eng Copernicus Publications http://www.biogeosciences.net/13/2291/2016/bg-13-2291-2016.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-13-2291-2016 https://doaj.org/article/f25741ccc8784fe9bfaf4e0b34c2ab03 Biogeosciences, Vol 13, Iss 8, Pp 2291-2303 (2016) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/bg-13-2291-2016 2022-12-31T01:28:54Z Soil carbon stored in high-latitude permafrost landscapes is threatened by warming and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Thermokarst and permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, are present across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO 2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO 2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season, the undisturbed tundra was a small net sink (NEE = −0.1 g C m −2 d −1 ); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.4 g C m −2 d −1 ). Over the measurement period, the undisturbed tundra sequestered 3.8 g C m −2 , while the disturbed tundra released 12.5 g C m −2 . Before full leaf-out in early July, the undisturbed tundra was a small source of CO 2 but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO 2 throughout the season. A static chamber system was also used to measure daytime fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration ( R e ) and gross primary production (GPP). Average GPP and R e found in disturbed tundra were smaller (+0.40 µmol m −2 s −1 and +0.55 µmol m −2 s −1 , respectively) than those found in undisturbed tundra (+1.19 µmol m −2 s −1 and +1.04 µmol m −2 s −1 , respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO 2 during the majority of the growing season (late June and July). Article in Journal/Newspaper Arctic Ellesmere Island Fosheim Peninsula permafrost Thermokarst Tundra Directory of Open Access Journals: DOAJ Articles Arctic Canada Ellesmere Island Fosheim Peninsula ENVELOPE(-83.749,-83.749,79.669,79.669) Biogeosciences 13 8 2291 2303 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
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 A. E. Cassidy A. Christen G. H. R. Henry The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Soil carbon stored in high-latitude permafrost landscapes is threatened by warming and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Thermokarst and permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, are present across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO 2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO 2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season, the undisturbed tundra was a small net sink (NEE = −0.1 g C m −2 d −1 ); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.4 g C m −2 d −1 ). Over the measurement period, the undisturbed tundra sequestered 3.8 g C m −2 , while the disturbed tundra released 12.5 g C m −2 . Before full leaf-out in early July, the undisturbed tundra was a small source of CO 2 but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO 2 throughout the season. A static chamber system was also used to measure daytime fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration ( R e ) and gross primary production (GPP). Average GPP and R e found in disturbed tundra were smaller (+0.40 µmol m −2 s −1 and +0.55 µmol m −2 s −1 , respectively) than those found in undisturbed tundra (+1.19 µmol m −2 s −1 and +1.04 µmol m −2 s −1 , respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO 2 during the majority of the growing season (late June and July). |
format |
Article in Journal/Newspaper |
author |
A. E. Cassidy A. Christen G. H. R. Henry |
author_facet |
A. E. Cassidy A. Christen G. H. R. Henry |
author_sort |
A. E. Cassidy |
title |
The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem |
title_short |
The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem |
title_full |
The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem |
title_fullStr |
The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem |
title_full_unstemmed |
The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem |
title_sort |
effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high arctic tundra ecosystem |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/bg-13-2291-2016 https://doaj.org/article/f25741ccc8784fe9bfaf4e0b34c2ab03 |
long_lat |
ENVELOPE(-83.749,-83.749,79.669,79.669) |
geographic |
Arctic Canada Ellesmere Island Fosheim Peninsula |
geographic_facet |
Arctic Canada Ellesmere Island Fosheim Peninsula |
genre |
Arctic Ellesmere Island Fosheim Peninsula permafrost Thermokarst Tundra |
genre_facet |
Arctic Ellesmere Island Fosheim Peninsula permafrost Thermokarst Tundra |
op_source |
Biogeosciences, Vol 13, Iss 8, Pp 2291-2303 (2016) |
op_relation |
http://www.biogeosciences.net/13/2291/2016/bg-13-2291-2016.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-13-2291-2016 https://doaj.org/article/f25741ccc8784fe9bfaf4e0b34c2ab03 |
op_doi |
https://doi.org/10.5194/bg-13-2291-2016 |
container_title |
Biogeosciences |
container_volume |
13 |
container_issue |
8 |
container_start_page |
2291 |
op_container_end_page |
2303 |
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1766330259309854720 |