Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada
Tundra-atmosphere exchanges of carbon dioxide (CO2) and water vapour were measured near Daring Lake, Northwest Territories in the Canadian Low Arctic for 3 years, 2004-2006. The measurement period spanned late-winter until the end of the growing period. Mean temperatures during the measurement perio...
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ftcarletonunivir:oai:carleton.ca:3630 2023-05-15T14:58:10+02:00 Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada Lafleur, P.M. (Peter M.) Humphreys, E. (Elyn) 2008-04-01 https://ir.library.carleton.ca/pub/3630 https://doi.org/10.1111/j.1365-2486.2007.01529.x en eng https://ir.library.carleton.ca/pub/3630 doi:10.1111/j.1365-2486.2007.01529.x Global Change Biology vol. 14 no. 4, pp. 740-756 Arctic Carbon balance Evapotranspiration NEE Tundra Water use efficiency info:eu-repo/semantics/article 2008 ftcarletonunivir https://doi.org/10.1111/j.1365-2486.2007.01529.x 2022-02-06T21:52:01Z Tundra-atmosphere exchanges of carbon dioxide (CO2) and water vapour were measured near Daring Lake, Northwest Territories in the Canadian Low Arctic for 3 years, 2004-2006. The measurement period spanned late-winter until the end of the growing period. Mean temperatures during the measurement period varied from about 2 °C less than historical average in 2004 and 2005 to 2 °C greater in 2006. Much of the added warmth in 2006 occurred at the beginning of the study, when snow melt occurred 3 weeks earlier than in the other years. Total precipitation in 2006 (163 mm) was more than double that of the driest year, 2004 (71 mm). The tundra was a net sink for CO2 carbon in all years. Mid-summer net ecosystem exchange of CO2 (NEE) achieved maximum values of -1.3 g Cm-2 day-1 (2004) to -1.8 g Cm-2 day-1 (2006). Accumulated NEE values over the 109-day period were -32,-51 and -61 g Cm-2 in 2004, 2005 and 2006, respectively. The larger CO2 uptake in 2006 was attributed to the early spring coupled with warmer air and soil conditions. In 2004, CO2 uptake was limited by the shorter growing season and mid-summer dryness, which likely reduced ecosystem productivity. Seasonal total evapotranspiration (ET) ranged from 130 mm (2004) to 181 mm (2006) and varied in accordance with the precipitation received and with the timing of snow melt. Maximum daily ET rates ranged from 2.3 to 2.7 mm day-1, occurring in mid July. Ecosystem water use efficiency (WUEeco) varied slightly between years, ranging from 2.2 in the driest year to 2.5 in the year with intermediate rainfall amounts. In the wettest year, increased soil evaporation may have contributed to a lower WUEeco (2.3). We speculate that most, if not all, of the modest growing season CO2 sink measured at this site could be lost due to fall and winter respiration leading to the tundra being a net CO2 source or CO2 neutral on an annual basis. However, this hypothesis is untested as yet. Article in Journal/Newspaper Arctic Northwest Territories Tundra Carleton University's Institutional Repository Arctic Canada Daring Lake ENVELOPE(-111.635,-111.635,64.834,64.834) Northwest Territories Global Change Biology 14 4 740 756 |
institution |
Open Polar |
collection |
Carleton University's Institutional Repository |
op_collection_id |
ftcarletonunivir |
language |
English |
topic |
Arctic Carbon balance Evapotranspiration NEE Tundra Water use efficiency |
spellingShingle |
Arctic Carbon balance Evapotranspiration NEE Tundra Water use efficiency Lafleur, P.M. (Peter M.) Humphreys, E. (Elyn) Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada |
topic_facet |
Arctic Carbon balance Evapotranspiration NEE Tundra Water use efficiency |
description |
Tundra-atmosphere exchanges of carbon dioxide (CO2) and water vapour were measured near Daring Lake, Northwest Territories in the Canadian Low Arctic for 3 years, 2004-2006. The measurement period spanned late-winter until the end of the growing period. Mean temperatures during the measurement period varied from about 2 °C less than historical average in 2004 and 2005 to 2 °C greater in 2006. Much of the added warmth in 2006 occurred at the beginning of the study, when snow melt occurred 3 weeks earlier than in the other years. Total precipitation in 2006 (163 mm) was more than double that of the driest year, 2004 (71 mm). The tundra was a net sink for CO2 carbon in all years. Mid-summer net ecosystem exchange of CO2 (NEE) achieved maximum values of -1.3 g Cm-2 day-1 (2004) to -1.8 g Cm-2 day-1 (2006). Accumulated NEE values over the 109-day period were -32,-51 and -61 g Cm-2 in 2004, 2005 and 2006, respectively. The larger CO2 uptake in 2006 was attributed to the early spring coupled with warmer air and soil conditions. In 2004, CO2 uptake was limited by the shorter growing season and mid-summer dryness, which likely reduced ecosystem productivity. Seasonal total evapotranspiration (ET) ranged from 130 mm (2004) to 181 mm (2006) and varied in accordance with the precipitation received and with the timing of snow melt. Maximum daily ET rates ranged from 2.3 to 2.7 mm day-1, occurring in mid July. Ecosystem water use efficiency (WUEeco) varied slightly between years, ranging from 2.2 in the driest year to 2.5 in the year with intermediate rainfall amounts. In the wettest year, increased soil evaporation may have contributed to a lower WUEeco (2.3). We speculate that most, if not all, of the modest growing season CO2 sink measured at this site could be lost due to fall and winter respiration leading to the tundra being a net CO2 source or CO2 neutral on an annual basis. However, this hypothesis is untested as yet. |
format |
Article in Journal/Newspaper |
author |
Lafleur, P.M. (Peter M.) Humphreys, E. (Elyn) |
author_facet |
Lafleur, P.M. (Peter M.) Humphreys, E. (Elyn) |
author_sort |
Lafleur, P.M. (Peter M.) |
title |
Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada |
title_short |
Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada |
title_full |
Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada |
title_fullStr |
Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada |
title_full_unstemmed |
Spring warming and carbon dioxide exchange over low Arctic tundra in central Canada |
title_sort |
spring warming and carbon dioxide exchange over low arctic tundra in central canada |
publishDate |
2008 |
url |
https://ir.library.carleton.ca/pub/3630 https://doi.org/10.1111/j.1365-2486.2007.01529.x |
long_lat |
ENVELOPE(-111.635,-111.635,64.834,64.834) |
geographic |
Arctic Canada Daring Lake Northwest Territories |
geographic_facet |
Arctic Canada Daring Lake Northwest Territories |
genre |
Arctic Northwest Territories Tundra |
genre_facet |
Arctic Northwest Territories Tundra |
op_source |
Global Change Biology vol. 14 no. 4, pp. 740-756 |
op_relation |
https://ir.library.carleton.ca/pub/3630 doi:10.1111/j.1365-2486.2007.01529.x |
op_doi |
https://doi.org/10.1111/j.1365-2486.2007.01529.x |
container_title |
Global Change Biology |
container_volume |
14 |
container_issue |
4 |
container_start_page |
740 |
op_container_end_page |
756 |
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1766330251103698944 |