Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems
Significant warming of Arctic and northern regions is ongoing and may greatly alter the carbon cycle of these regions. During the International Polar Year, an extensive study was carried out in the Eastern Canadian subarctic and Arctic in order to characterize CO2 and CH4 exchanges from these potent...
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ftdatacite:10.20381/ruor-3994 2023-05-15T14:48:43+02:00 Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems Pilote, Martin 2015 https://dx.doi.org/10.20381/ruor-3994 http://www.ruor.uottawa.ca/handle/10393/33426 en eng Université d'Ottawa / University of Ottawa Gas exchange Carbon balance NEE CO2 CH4 Environmental factor Temperature Precipitation Arctic Subarctic Spatial trend Temporal trend Text Thesis article-journal ScholarlyArticle 2015 ftdatacite https://doi.org/10.20381/ruor-3994 2021-11-05T12:55:41Z Significant warming of Arctic and northern regions is ongoing and may greatly alter the carbon cycle of these regions. During the International Polar Year, an extensive study was carried out in the Eastern Canadian subarctic and Arctic in order to characterize CO2 and CH4 exchanges from these potentially sensitive ecosystems. The main objectives of this study were to identify the land cover and environmental factors leading to greatest CO2 and CH4 emissions in a highly heterogeneous subarctic landscape, to quantify interannual variability in the net ecosystem exchange of CO2 (NEE) in subarctic forest tundra and investigate the weather conditions that increase net uptake of CO2, and finally, to evaluate the general trends of mid-summer NEE along a latitudinal gradient spanning from 55° to the 72° north. At the landscape level, CO2 and CH4 exchanges showed large variability. Although CH4 emissions were greatest in wetlands, their areal coverage is small in the Kuujuarapik area and limited the influence of these CH4 sources. At the ecosystem level, large-scale atmospheric processes controlled growing season length and cumulative growing degree days which greatly influenced annual and seasonal NEE trends. The subarctic forest tundra near Kuujuarapik was a net source of CO2 in all 3 study years but the source strength was least with the greatest growing degree days while the length of the snow-free period appeared to be less important. Across a latitudinal gradient covering subarctic forest tundra to Arctic tundra, variations in summer NEE could be linked to surface organic carbon content with higher net CO2 uptake at sites with greater soil organic carbon. Warmer days tended to correlate with smaller daily net CO2 uptake (or greater net CO2 losses) but overall, warmer growing seasons reduced the net losses of CO2 on an annual basis. Carbon fluxes in Eastern Canadian subarctic and Arctic regions are highly variable in space and time but these observations help establish a baseline for future examinations of how these carbon exchanges may change with further warming. Thesis Arctic International Polar Year Subarctic Tundra DataCite Metadata Store (German National Library of Science and Technology) Arctic |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Gas exchange Carbon balance NEE CO2 CH4 Environmental factor Temperature Precipitation Arctic Subarctic Spatial trend Temporal trend |
spellingShingle |
Gas exchange Carbon balance NEE CO2 CH4 Environmental factor Temperature Precipitation Arctic Subarctic Spatial trend Temporal trend Pilote, Martin Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems |
topic_facet |
Gas exchange Carbon balance NEE CO2 CH4 Environmental factor Temperature Precipitation Arctic Subarctic Spatial trend Temporal trend |
description |
Significant warming of Arctic and northern regions is ongoing and may greatly alter the carbon cycle of these regions. During the International Polar Year, an extensive study was carried out in the Eastern Canadian subarctic and Arctic in order to characterize CO2 and CH4 exchanges from these potentially sensitive ecosystems. The main objectives of this study were to identify the land cover and environmental factors leading to greatest CO2 and CH4 emissions in a highly heterogeneous subarctic landscape, to quantify interannual variability in the net ecosystem exchange of CO2 (NEE) in subarctic forest tundra and investigate the weather conditions that increase net uptake of CO2, and finally, to evaluate the general trends of mid-summer NEE along a latitudinal gradient spanning from 55° to the 72° north. At the landscape level, CO2 and CH4 exchanges showed large variability. Although CH4 emissions were greatest in wetlands, their areal coverage is small in the Kuujuarapik area and limited the influence of these CH4 sources. At the ecosystem level, large-scale atmospheric processes controlled growing season length and cumulative growing degree days which greatly influenced annual and seasonal NEE trends. The subarctic forest tundra near Kuujuarapik was a net source of CO2 in all 3 study years but the source strength was least with the greatest growing degree days while the length of the snow-free period appeared to be less important. Across a latitudinal gradient covering subarctic forest tundra to Arctic tundra, variations in summer NEE could be linked to surface organic carbon content with higher net CO2 uptake at sites with greater soil organic carbon. Warmer days tended to correlate with smaller daily net CO2 uptake (or greater net CO2 losses) but overall, warmer growing seasons reduced the net losses of CO2 on an annual basis. Carbon fluxes in Eastern Canadian subarctic and Arctic regions are highly variable in space and time but these observations help establish a baseline for future examinations of how these carbon exchanges may change with further warming. |
format |
Thesis |
author |
Pilote, Martin |
author_facet |
Pilote, Martin |
author_sort |
Pilote, Martin |
title |
Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems |
title_short |
Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems |
title_full |
Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems |
title_fullStr |
Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems |
title_full_unstemmed |
Trends in the Exchange of CO2 and CH4 between the Atmosphere and Eastern Canadian Subarctic and Arctic Ecosystems |
title_sort |
trends in the exchange of co2 and ch4 between the atmosphere and eastern canadian subarctic and arctic ecosystems |
publisher |
Université d'Ottawa / University of Ottawa |
publishDate |
2015 |
url |
https://dx.doi.org/10.20381/ruor-3994 http://www.ruor.uottawa.ca/handle/10393/33426 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic International Polar Year Subarctic Tundra |
genre_facet |
Arctic International Polar Year Subarctic Tundra |
op_doi |
https://doi.org/10.20381/ruor-3994 |
_version_ |
1766319803605188608 |