Tundra shrub effects on growing season energy and carbon dioxide exchange
Increased shrub cover on the Arctic tundra is expected to impact ecosystem-atmosphere exchanges of carbon and energy resulting in feedbacks to the climate system, yet few direct measurements of shrub tundra-atmosphere exchanges are available to corroborate expectations. Here we present energy and ca...
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ftdoajarticles:oai:doaj.org/article:2186472d561d47d0a49382d705adacc4 2023-09-05T13:11:29+02:00 Tundra shrub effects on growing season energy and carbon dioxide exchange Peter M Lafleur Elyn R Humphreys 2018-01-01T00:00:00Z https://doi.org/10.1088/1748-9326/aab863 https://doaj.org/article/2186472d561d47d0a49382d705adacc4 EN eng IOP Publishing https://doi.org/10.1088/1748-9326/aab863 https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/aab863 1748-9326 https://doaj.org/article/2186472d561d47d0a49382d705adacc4 Environmental Research Letters, Vol 13, Iss 5, p 055001 (2018) Arctic tundra tundra-atmopshere interaction carbon cycle energy balance shrub cover Arctic change Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 article 2018 ftdoajarticles https://doi.org/10.1088/1748-9326/aab863 2023-08-13T00:37:40Z Increased shrub cover on the Arctic tundra is expected to impact ecosystem-atmosphere exchanges of carbon and energy resulting in feedbacks to the climate system, yet few direct measurements of shrub tundra-atmosphere exchanges are available to corroborate expectations. Here we present energy and carbon dioxide (CO _2 ) fluxes measured using the eddy covariance technique over six growing seasons at three closely located tundra sites in Canada’s Low Arctic. The sites are dominated by the tundra shrub Betula glandulosa , but percent cover varies from 17%–60% and average shrub height ranges from 18–59 cm among sites. The site with greatest percent cover and height had greater snow accumulation, but contrary to some expectations, it had similar late-winter albedo and snow melt dates compared to the other two sites. Immediately after snowmelt latent heat fluxes increased more slowly at this site compared to the others. Yet by the end of the growing season there was little difference in cumulative latent heat flux among the sites, suggesting evapotranspiration was not increased with greater shrub cover. In contrast, lower albedo and less soil thaw contributed to greater summer sensible heat flux at the site with greatest shrub cover, resulting in greater total atmospheric heating. Net ecosystem exchange of CO _2 revealed the potential for enhanced carbon cycling rates under greater shrub cover. Spring CO _2 emissions were greatest at the site with greatest percent cover of shrubs, as was summer net uptake of CO _2 . The seasonal net sink for CO _2 was ~2 times larger at the site with the greatest shrub cover compared to the site with the least shrub cover. These results largely agree with expectations that the growing season feedback to the atmosphere arising from shrub expansion in the Arctic has the potential to be negative for CO _2 fluxes but positive for turbulent energy fluxes. Article in Journal/Newspaper albedo Arctic Tundra Directory of Open Access Journals: DOAJ Articles Arctic Environmental Research Letters 13 5 055001 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Arctic tundra tundra-atmopshere interaction carbon cycle energy balance shrub cover Arctic change Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
spellingShingle |
Arctic tundra tundra-atmopshere interaction carbon cycle energy balance shrub cover Arctic change Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 Peter M Lafleur Elyn R Humphreys Tundra shrub effects on growing season energy and carbon dioxide exchange |
topic_facet |
Arctic tundra tundra-atmopshere interaction carbon cycle energy balance shrub cover Arctic change Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
description |
Increased shrub cover on the Arctic tundra is expected to impact ecosystem-atmosphere exchanges of carbon and energy resulting in feedbacks to the climate system, yet few direct measurements of shrub tundra-atmosphere exchanges are available to corroborate expectations. Here we present energy and carbon dioxide (CO _2 ) fluxes measured using the eddy covariance technique over six growing seasons at three closely located tundra sites in Canada’s Low Arctic. The sites are dominated by the tundra shrub Betula glandulosa , but percent cover varies from 17%–60% and average shrub height ranges from 18–59 cm among sites. The site with greatest percent cover and height had greater snow accumulation, but contrary to some expectations, it had similar late-winter albedo and snow melt dates compared to the other two sites. Immediately after snowmelt latent heat fluxes increased more slowly at this site compared to the others. Yet by the end of the growing season there was little difference in cumulative latent heat flux among the sites, suggesting evapotranspiration was not increased with greater shrub cover. In contrast, lower albedo and less soil thaw contributed to greater summer sensible heat flux at the site with greatest shrub cover, resulting in greater total atmospheric heating. Net ecosystem exchange of CO _2 revealed the potential for enhanced carbon cycling rates under greater shrub cover. Spring CO _2 emissions were greatest at the site with greatest percent cover of shrubs, as was summer net uptake of CO _2 . The seasonal net sink for CO _2 was ~2 times larger at the site with the greatest shrub cover compared to the site with the least shrub cover. These results largely agree with expectations that the growing season feedback to the atmosphere arising from shrub expansion in the Arctic has the potential to be negative for CO _2 fluxes but positive for turbulent energy fluxes. |
format |
Article in Journal/Newspaper |
author |
Peter M Lafleur Elyn R Humphreys |
author_facet |
Peter M Lafleur Elyn R Humphreys |
author_sort |
Peter M Lafleur |
title |
Tundra shrub effects on growing season energy and carbon dioxide exchange |
title_short |
Tundra shrub effects on growing season energy and carbon dioxide exchange |
title_full |
Tundra shrub effects on growing season energy and carbon dioxide exchange |
title_fullStr |
Tundra shrub effects on growing season energy and carbon dioxide exchange |
title_full_unstemmed |
Tundra shrub effects on growing season energy and carbon dioxide exchange |
title_sort |
tundra shrub effects on growing season energy and carbon dioxide exchange |
publisher |
IOP Publishing |
publishDate |
2018 |
url |
https://doi.org/10.1088/1748-9326/aab863 https://doaj.org/article/2186472d561d47d0a49382d705adacc4 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
albedo Arctic Tundra |
genre_facet |
albedo Arctic Tundra |
op_source |
Environmental Research Letters, Vol 13, Iss 5, p 055001 (2018) |
op_relation |
https://doi.org/10.1088/1748-9326/aab863 https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/aab863 1748-9326 https://doaj.org/article/2186472d561d47d0a49382d705adacc4 |
op_doi |
https://doi.org/10.1088/1748-9326/aab863 |
container_title |
Environmental Research Letters |
container_volume |
13 |
container_issue |
5 |
container_start_page |
055001 |
_version_ |
1776204852640088064 |