CO<sub>2</sub>Exchanges within Zones of Rapid Conversion from Permafrost Plateau to Bog and Fen Land Cover Types

Chasmer, L.; Kenward, A.; Quinton, William L.; Petrone, Richard M.

doi:10.1657/1938-4246-44.4.399

Cited by 14 publications

(11 citation statements)

References 83 publications

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“…Quinton et al [] reported that due to permafrost degradation between 1970 and 2008, in the Northwest Territories, Canada, black spruce forest on permafrost plateau decreased by 11%, while bogs and fens increased by 8% and 3%, respectively. Chasmer et al [] examined CO 2 fluxes during springtime in 2008 in this same landscape, and found that the bog was the greatest source of CO 2 during this time, followed by the permafrost plateau and fen. These findings contrast somewhat with this study, where we found that during each year between March 1 and May 15, the bog could show large emissions of CO 2 , but this was highly variable (NEE of 2–3 g C m −2 in 2011 and 2012 and 40 g C m −2 in 2013; Table ).…”

Section: Discussionmentioning

confidence: 99%

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Euskirchen

Edgar

Turetsky

et al. 2014

J. Geophys. Res. Biogeosci.

111

115

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Changes in vegetation and soil properties following permafrost degradation and thermokarst development in peatlands may cause changes in net carbon storage. To better understand these dynamics, we established three sites in Alaska that vary in permafrost regime, including a black spruce peat plateau forest with stable permafrost, an internal collapse scar bog formed as a result of thermokarst, and a rich fen without permafrost. Measurements include year‐round eddy covariance estimates of carbon dioxide (CO2), water, and energy fluxes, associated environmental variables, and methane (CH4) fluxes at the collapse scar bog. The ecosystems all acted as net sinks of CO2 in 2011 and 2012, when air temperature and precipitation remained near long‐term means. In 2013, under a late snowmelt and late leaf out followed by a hot, dry summer, the permafrost forest and collapse scar bog were sources of CO2. In this same year, CO2 uptake in the fen increased, largely because summer inundation from groundwater inputs suppressed ecosystem respiration. CO2 exchange in the permafrost forest and collapse scar bog was sensitive to warm air temperatures, with 0.5 g C m−2 lost each day when maximum air temperature was very warm (≥29°C). The bog lost 4981 ± 300 mg CH4 m−2 between April and September 2013, indicating that this ecosystem acted as a significant source of both CO2 and CH4 to the atmosphere in 2013. These results suggest that boreal peatland responses to warming and drying, both of which are expected to occur in a changing climate, will depend on permafrost regime.

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Section: Discussionmentioning

confidence: 99%

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Euskirchen

Edgar

Turetsky

et al. 2014

J. Geophys. Res. Biogeosci.

111

115

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“…Three boardwalk transects of 20 m length and nine plots each were set up for ease of sampling and to minimize disturbance to the plots. Each transect spanned the main stages of thaw that are generally recognized in permafrost studies: intact permafrost, intermediate thaw, and fully thawed (e.g., Bäckstrand et al 2010;Chasmer et al 2012;Turetsky 2004). The three transects also captured several transitional stages between the thaw classes.…”

Section: Study Site and Experimental Designmentioning

confidence: 99%

Post-thaw variability in litter decomposition best explained by microtopography at an ice-rich permafrost peatland

Malhotra

Moore

Limpens

et al. 2018

Arctic, Antarctic, and Alpine Research

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Litter decomposition, a key process by which recently fixed carbon is lost from ecosystems, is a function of environmental conditions and plant community characteristics. In ice-rich peatlands, permafrost thaw introduces high variability in both abiotic and biotic factors, both of which may affect litter decomposition rates in different ways. Can the existing conceptual frameworks of litter decomposition and its controls be applied across a structurally heterogeneous thaw gradient? We investigated the variability in litter decomposition and its predictors at the Stordalen subarctic peatland in northern Sweden. We measured in situ decomposition of representative litter and environments using litter bags throughout two years. We found highly variable litter decomposition rates with turnover times ranging from five months to four years. Surface elevation was a strong correlate of litter decomposition across the landscape, likely as it integrates multiple environmental and plant community changes brought about by thaw. There was faster decomposition but also more mass remaining after two years in thawed areas relative to permafrost areas, suggesting faster initial loss of carbon but more storage into the slow-decomposing carbon pool. Our results highlight mechanisms and predictors of carbon cycle changes in ice-rich peatlands following permafrost thaw.

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“…On one hand, conversion of wetlands to drylands can result in a shift from a strong CH 4 source to a weak sink (Jiang et al, 2009); on the other hand, conversion of wetlands to agricultural lands with cropping activities can potentially lead to increases in N 2 O emission (Roulet, 2000). Therefore, future research requires the establishment of a full wetland ecosystem or land cover greenhouse gas measurement program (Chasmer et al, 2012), including CO 2 fluxes as well as dissolved organic C, and soil CH 4 and N 2 O emission, in order to clarify the responses of wetland C exchange caused by land conversion in the long-term.…”

Section: Effect Of Wetland Reclamation On Carbon Sequestrationmentioning

confidence: 99%

Agricultural reclamation effects on ecosystem CO2 exchange of a coastal wetland in the Yellow River Delta

Han

Xing

et al. 2014

Agriculture, Ecosystems & Environment

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a b s t r a c tLittle is known about the impacts of agricultural exploitation of coastal wetlands on ecosystem CO 2 exchange, although coastal wetlands have been widely reclaimed for agricultural use across the world. We measured net ecosystem CO 2 exchange (NEE) and its major components, gross primary production (GPP) and ecosystem respiration (R eco ) using an eddy covariance flux technique in a natural coastal wetland (reed) and an adjacent, newly reclaimed farmland (cotton) in the Yellow River Delta, China. The results showed that agricultural reclamation changed the ecosystem CO 2 exchange of the coastal wetland at three distinct levels. Initially, the conversion from the wetland to farmland changed the light response parameters (˛, A max , and R eco, day ) of NEE and temperature sensitivity (Q 10 ) of R eco mainly by changing the dominant vegetation type. Over the growing season, NEE, R eco and GPP were significantly correlated with LAI at both sites and aboveground biomass at the farmland site. Next, the reclamation of wetland modified the diurnal and seasonal dynamics of ecosystem CO 2 exchange. Significant differences in diurnal variations of NEE between the wetland and farmland sites were found during the growing season (with the exception of June and July). Seasonal means of daily GPP and R eco values at the wetland site were higher than those at the farmland. Ultimately, the agricultural reclamation altered the CO 2 sequestration capacity of the coastal wetland. The cumulative NEE in the wetland (−237.4 g C m −2 ) was higher than that in the farmland (−202.0 g C m −2 ). When biomass removal was taken into account, the farmland was a strong source for CO 2 of around 131.9 g C m −2 during the growing season. Overall, land use changes by reclamation altered ecosystem CO 2 exchange at several ecological scales by changing the dominant vegetation type and altering the ecosystem's natural development.

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CO₂Exchanges within Zones of Rapid Conversion from Permafrost Plateau to Bog and Fen Land Cover Types

Cited by 14 publications

References 83 publications

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Post-thaw variability in litter decomposition best explained by microtopography at an ice-rich permafrost peatland

Agricultural reclamation effects on ecosystem CO2 exchange of a coastal wetland in the Yellow River Delta

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CO2Exchanges within Zones of Rapid Conversion from Permafrost Plateau to Bog and Fen Land Cover Types

Cited by 14 publications

References 83 publications

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Post-thaw variability in litter decomposition best explained by microtopography at an ice-rich permafrost peatland

Agricultural reclamation effects on ecosystem CO2 exchange of a coastal wetland in the Yellow River Delta

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CO₂Exchanges within Zones of Rapid Conversion from Permafrost Plateau to Bog and Fen Land Cover Types