New low-cost automated system of closed chambers to measure greenhouse gas emissions from the tundra

Gagnon, Serge; L'Hérault, E.; Lemay, Martin; Allard, Michel

doi:10.1016/j.agrformet.2016.06.012

Cited by 9 publications

(9 citation statements)

References 34 publications

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“…A sampling period of 30 min was chosen to ensure stability in the CO 2 fluxes (Lai et al 2012). Although this could have caused some underestimation in flux values due to buildup of gas in the chamber headspace and thus a larger decrease in the concentration gradient (Healy et al 1996;Pumpanen et al 2004), CO 2 concentration increases with time remained close to linear in all chambers (see Gagnon et al (2016) for complete data).…”

Section: Ecosystem Respirationmentioning

confidence: 99%

“…An automated system involving four opaque closed chambers recording ER (K-30; CO2Meter Inc., Ormond Beach, Florida, USA) was developed for this study (Gagnon et al 2016). Each chamber had a volume of 26.14 L, covered an area of 1029 cm 2 , and was 25.40 cm high.…”

Section: Automated System Of Opaque Closed Chambersmentioning

confidence: 99%

“…The collars were installed by cutting a slot with a knife 5 days before the beginning of measurements to minimize the initial effects of severing roots and disturbing soil structure (Davidson et al 2002). A more complete review of the design of the chambers, their performance, and details on flux calculation can be found in Gagnon et al (2016).…”

Section: Automated System Of Opaque Closed Chambersmentioning

confidence: 99%

“…Flux measurements were accepted when the regression fits were significant (p < 0.05). In addition, fluxes with unrealistic concentration measurements that could give abnormally high exchange rates and unstable gas measurements related to random system errors were discarded (Christiansen et al 2015;Gagnon et al 2016).…”

Section: Data Sorting and Statistical Analysesmentioning

confidence: 99%

“…We calculated ER fluxes manually from the concentrations collected with the ACs using quadratic regressions on CO 2 concentration against time to account for nonlinear behavior (Wagner et al 1997;Gagnon et al 2016). The first CO 2 concentration measurements (t = 0 s) of ER fluxes were systematically removed; in some instances (n < 5), up to the first 5 min of recording was removed because of fluctuations caused by chamber placement (Davidson et al 2002).…”

Section: Data Sorting and Statistical Analysesmentioning

confidence: 99%

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Diurnal and seasonal variations of tundra CO<sub>2</sub> emissions in a polygonal peatland near Salluit, Nunavik, Canada

Gagnon¹,

Allard²,

Nicosia

2017

Arctic Science

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Polygonal peatlands are carbon-rich permafrost ecosystems that will likely be significantly affected by climate change. However, studies are often constrained to one measurement per day, which impedes assessments of the temporal variability in carbon fluxes. For this reason, we measured ecosystem respiration (ER) of CO 2 in a polygonal peatland underlain by continuous permafrost over an entire growing season to determine the effects of temperature and water table depth on the temporal variability of ER. We used four automated closed chambers to measure ER under varying temperature and soil moisture regimes. Temporal variability was approximately the same for the four plots, on both a diurnal and a seasonal scale. Both diurnal and seasonal variations in ER were strongly controlled by changes in soil surface temperature. Fluctuations of the water table depth associated with important rainfall events was also an important factor affecting ER on the seasonal scale. We found that water table level fluctuations below 20-25 cm did not significantly affect ER and that most soil respiration took place in the top 10 cm, likely in the surface 2 cm. Our results highlight the importance of monitoring future changes in tundra hydrology, which will determine the depth of organic matter available for aerobic decomposition.Key words: permafrost, tundra, polygonal peatland, carbon dioxide, water table.Résumé : Les tourbières polygonales sont des écosystèmes de pergélisol riches en carbone qui seront probablement significativement touchés en raison du changement climatique. Cependant, les études sont souvent contraintes à une mesure par jour, ce qui empêche les évaluations de la variabilité temporelle des flux de carbone. C'est pourquoi nous avons mesuré la respiration de l'écosystème (RÉ) au niveau du CO 2 dans une tourbière polygonale chevauchant un pergélisol continu au cours d'une saison de croissance entière dans le but de déterminer les effets de température et de profondeur de nappe phréatique sur la variabilité temporelle de la RÉ. Nous avons utilisé quatre caissons fermés automatisés afin de mesurer la RÉ sous divers régimes de changement de température et d'humidité du sol. La variabilité temporelle était approximativement la même pour les quatre parcelles de terrain, et ce, à l'échelle tant diurne que saisonnière. Les variations tant diurnes que saisonnières de la RÉ étaient fortement liées aux changements de température du sol de surface. Les fluctuations de profondeur de la nappe phréatique associées aux événements pluvieux importants constituaient aussi un facteur important influant sur la RÉ à l'échelle saisonnière. Nous avons constaté que les fluctuations du niveau de la nappe phréatique au-dessous de 20-25 cm n'ont pas eu d'effets significatifs sur la RÉ et que la grande partie

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Section: Ecosystem Respirationmentioning

confidence: 99%

Section: Automated System Of Opaque Closed Chambersmentioning

confidence: 99%

Section: Automated System Of Opaque Closed Chambersmentioning

confidence: 99%

Section: Data Sorting and Statistical Analysesmentioning

confidence: 99%

Section: Data Sorting and Statistical Analysesmentioning

confidence: 99%

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Diurnal and seasonal variations of tundra CO<sub>2</sub> emissions in a polygonal peatland near Salluit, Nunavik, Canada

Gagnon¹,

Allard²,

Nicosia

2017

Arctic Science

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Changes in ice‐wedge activity over 25 years of climate change near Salluit, Nunavik (northern Québec, Canada)

Gagnon

Allard

2020

Permafrost & Periglacial

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To assess the direct impact of climate change on ice‐wedge (IW) degradation, 16 sites in the Narsajuaq river valley (Nunavik, Canada) that were extensively studied between 1989 and 1991 were revisited in 2016, 2017 and 2018. In total, 109 pits were dug to record soil characteristics and IW shapes and depths. Changes in surface conditions were also noted using side‐by‐side comparisons of recent (2017) and older (1989–1991) land and aerial photographs. During the past 25 years, the active layer reached depths that were 1.2–3.4 times deeper than in 1991, which led to the widespread degradation of IWs in the valley. Whereas 94% of the IWs unearthed in 1991 showed multiple recent growth structures, only 13% of the 55 IWs unearthed in 2017 still had some upgrowth stages left. IW tops are now consistently deeper than the main stages of the IWs measured in 1991. In August 2017, however, about half of the IWs had ice veins connecting them to the base of the active layer, an indication that the recent cooling spell (2010 to present) in the region was enough to reactivate frost cracking and IW growth. This paper highlights how sensitive the Arctic soil system can be to short‐term climate variations.

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Low cost CO2 sensing: A simple microcontroller approach with calibration and field use

et al. 2020

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New low-cost automated system of closed chambers to measure greenhouse gas emissions from the tundra

Cited by 9 publications

References 34 publications

Diurnal and seasonal variations of tundra CO<sub>2</sub> emissions in a polygonal peatland near Salluit, Nunavik, Canada

Diurnal and seasonal variations of tundra CO<sub>2</sub> emissions in a polygonal peatland near Salluit, Nunavik, Canada

Changes in ice‐wedge activity over 25 years of climate change near Salluit, Nunavik (northern Québec, Canada)

Low cost CO2 sensing: A simple microcontroller approach with calibration and field use

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