Seasonal dynamics of methane emissions from a subarctic fen in the Hudson Bay Lowlands

Hanis, K. L.; Tenuta, Mario; Amiro, B.D.; Papakyriakou, Tim

doi:10.5194/bg-10-4465-2013

Cited by 26 publications

(25 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…NEE determinations were also filtered to remove half-hourly periods at night (PAR < 10 µmol m −2 s −1 ) when the friction velocity was below a threshold of 0.2 m s −1 (Hanis et al 2013). All NEE from Station 2 were also filtered to remove halfhourly periods when the wind direction was 135°-225°to exclude directions from the tower and gas-powered generator.…”

Section: Discussionmentioning

confidence: 99%

“…All NEE from Station 2 were also filtered to remove halfhourly periods when the wind direction was 135°-225°to exclude directions from the tower and gas-powered generator. Filtering of F CH4 is described in Hanis et al (2013). After data filtering for periods with low friction velocity, as well as other quality control checks, data coverage for the study period (DOY 170-284) for NEE was 59% in 2007, 74% in 2008, 36% in 2010, and 45% in 2011.…”

Section: Discussionmentioning

confidence: 99%

“…and an understory of the moss Pseudocalliergon turgescens (Jensen) Loeske. Other sedges, cotton grass, rushes, and horsetails are also present (Hanis et al 2013). New shoots of C. aquatilis emerge shortly after spring melt from mid-to late June, flowering occurs in mid-July, and senescence begins in late August.…”

Section: Study Sitementioning

confidence: 99%

“…The atmospheric methane concentration was measured using a closedpath analyzer (RMT-200 fast methane analyzer (Los Gatos Research Inc., Mountain View, California) (Baer et al 2002;Hendriks et al 2008;Baldocchi et al 2011) at 10 Hz frequency. A detailed description of the RMT-200 setup is given in Hanis et al (2013).…”

Section: Study Sitementioning

confidence: 99%

“…The Churchill studies began in the 1990s (Burton et al 1996;Schreader et al 1998;Griffis et al 2000aGriffis et al , 2000bLafleur et al 2001;Rouse et al 2002) and have periodic continuity to recent years, although the methods have changed from gradient techniques to eddy covariance. At this same subarctic fen near Churchill, we previously reported the seasonal dynamics of methane fluxes for 2008-2011 measured using eddy covariance (Hanis et al 2013). In the current study, we report on NEE over the same period and the greenhouse gas budget (including methane) for this site.…”

Section: Introductionmentioning

confidence: 96%

See 4 more Smart Citations

Carbon exchange over four growing seasons for a subarctic sedge fen in northern Manitoba, Canada

et al. 2015

View full text Add to dashboard Cite

Net ecosystem exchange of carbon was measured using eddy covariance for four growing seasons at a subarctic hummocky fen in northern Manitoba, Canada. Over a 115 day measurement period each year, cumulative net ecosystem exchange of carbon ranged from a gain of 49 g C m −2 to a loss of 16 g C m −2 with a mean loss of 6 g C m −2 from the fen, with an uncertainty of about ±34 g C m −2. Ecosystem respiration decreased with higher water tables (r 2 = 0.3), especially in one summer when flooding occurred to 0.12 m above the peat surface. Additional methane emissions previously documented for the site of 4-5.7 g C m −2 year −1 added to the carbon loss. Carbon loss was measured from this same fen in the 1990s and it is likely that the carbon gain (peat accumulation) during past centuries has not continued in recent decades. Scaling to annual greenhouse gas emissions as a 100 year global warming potential showed that this fen is currently a source of 192-490 g CO 2 -equivalents m −2 year −1 based on both carbon dioxide and methane flux measurements, indicating that peat is decomposing. . La respiration de l'écosystème diminuait lorsque les nappes phréatiques étaient plus hautes (r 2 = 0.3), particulièrement un été durant lequel le niveau d'inondation a atteint 0,12 m au-dessus de la surface de la tourbe. Des émissions supplémentaires de méthane précédemment documentées pour le site de 4 à 5,7 g C m −2 a −1 ont contribué davantage à la perte de carbone. On avait mesuré la perte de carbone à ce même fen dans les années 1990 et il est probable que le gain de carbone (l'accumulation de tourbe) pendant des siècles passés n'a pas continué dans les décennies récentes. Une mise à l'échelle aux émissions de gaz à effet de serre annuelles comme un potentiel de réchauffement climatique sur 100 ans a montré que ce fen est actuellement une source de 192 à 490 g équivalents de CO 2 m −2 a −1 d'après les mesures tant du flux de dioxyde de carbone que de méthane, indiquant que la tourbe se décompose. [Traduit par la Rédaction]

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Study Sitementioning

confidence: 99%

Section: Study Sitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

See 3 more Smart Citations

Carbon exchange over four growing seasons for a subarctic sedge fen in northern Manitoba, Canada

et al. 2015

View full text Add to dashboard Cite

show abstract

Net ecosystem methane and carbon dioxide exchanges in a Lake Erie coastal marsh and a nearby cropland

et al. 2014

View full text Add to dashboard Cite

Net ecosystem carbon dioxide (F CO2 ) and methane (F CH4 ) exchanges were measured by using the eddy covariance method to quantify the atmospheric carbon budget at a Typha-and Nymphaea-dominated freshwater marsh (March 2011 to March 2013) and a soybean cropland (May 2011 to May 2012) in northwestern Ohio, USA. Two year average annual F CH4 (49.7 g C-CH 4 m À2 yr À1) from the marsh was high and compatible with its net annual CO 2 uptake (F CO2 : À21.0 g C-CO 2 m À2 yr À1). In contrast, F CH4 was small (2.3 g C-CH 4 m À2 yr À1) and accounted for a minor portion of the atmospheric carbon budget (F CO2 : À151.8 g C-CO 2 m À2 yr À1) at the cropland. At the seasonal scale, soil temperature associated with methane (CH 4 ) production provided the dominant regulator of F CH4 at the marsh (R 2 = 0.86). At the diurnal scale, plant-modulated gas flow was the major pathway for CH 4 outgassing in the growing season at the marsh. Diffusion and ebullition became the major pathways in the nongrowing season and were regulated by friction velocity. Our findings highlight the importance of freshwater marshes for their efficiency in turning over and releasing newly fixed carbon as CH 4 . Despite marshes accounting for only~4% of area in the agriculture-dominated landscape, their high F CH4 should be carefully addressed in the regional carbon budget.

show abstract

Evidence for a nonmonotonic relationship between ecosystem‐scale peatland methane emissions and water table depth

et al. 2014

View full text Add to dashboard Cite

Although temporal and spatial variations in peatland methane (CH 4 ) emissions at broad scales are often related to water table (WT) using a linear relationship, a potentially complex relationship exists between these variables locally and over shorter time scales. To explore this issue, CH 4 fluxes were measured using eddy covariance at the Mer Bleue bog over two summer seasons. Peak CH 4 emissions (30 to 50 mg CH 4 -C m À2 d À1 ) occurred not when the WT was closest to the surface but instead, when it dropped to 40 to 55 cm below the surface. When the WT was below or above this zone, average fluxes werẽ 14 mg CH 4 -C m À2 d À1 . We speculate this critical zone coincides with the necessary redox potentials and sources of fresh organic material that lead to maximum production of CH 4 and/or with conditions that lead to degassing of stored CH 4 . However, as expected, total summer CH 4 emissions were 47% lower during the drier year. This occurred in part because the WT was within the critical zone for fewer days in the drier year but also because after an extended midsummer dry period there was little recovery of CH 4 emissions, even a month after rewetting.

show abstract

Seasonal dynamics of methane emissions from a subarctic fen in the Hudson Bay Lowlands

Cited by 26 publications

References 44 publications

Carbon exchange over four growing seasons for a subarctic sedge fen in northern Manitoba, Canada

Carbon exchange over four growing seasons for a subarctic sedge fen in northern Manitoba, Canada

Net ecosystem methane and carbon dioxide exchanges in a Lake Erie coastal marsh and a nearby cropland

Evidence for a nonmonotonic relationship between ecosystem‐scale peatland methane emissions and water table depth

Contact Info

Product

Resources

About