Comparison of net ecosystem CO2 exchange in two peatlands in western Canada with contrasting dominant vegetation, Sphagnum and Carex

Glenn, Aaron J.; Flanagan, Lawrence B.; Syed, Kamran H.; Carlson, Peter J.

doi:10.1016/j.agrformet.2006.03.020

Cited by 70 publications

(53 citation statements)

References 61 publications

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“…Reco (g C m as single peak curves and be described by quadratic models, which were similar to those observed at other wetland ecosystems of Glenn et al (2006), Syed et al (2006), Zhou et al (2009), andHao et al (2011). During the growing season, the quantum yield˛was 0.033 mol CO 2 mol −1 photons ranging from 0.010 to 0.058 mol CO 2 mol −1 photons at the wetland site, which was close to an estuarine wetland (from 0.009 to 0.086 mol CO 2 mol −1 photons) in coastal Shanghai (Guo et al, 2009) and a freshwater tidal wetland (from 0.0098 to 0.036 mol CO 2 mol −1 photons) in Northeast China, and higher than other EC studies in Alpine wetland ecosystems in China (e.g.…”

Section: F-valuementioning

confidence: 65%

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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Section: F-valuementioning

confidence: 65%

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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“…In an analogous study in an Alaskan tundra ecosystem, Oechel et al (2000) found that the ecosystem initially changed from a CO 2 sink to a source due to warming and drying, but that CO 2 emissions decreased and eventually became negative during summers over a 40-year period. Several studies of CO 2 fluxes at wetlands have also indicated the importance of vegetation, both stand age for forested wetlands (Ball et al, 2007) and dominant plant community among different wetland types (Humphreys et al, 2006;Glenn et al, 2006;Vourlitis et al, 2000;Waddington et al, 1998). Understanding the impact of dominant plant communities on an ecosystem's response to changing climatic and hydrological conditions will be important for complete understanding of this issue.…”

Section: Discussionmentioning

confidence: 99%

“…Worldwide, wetlands contain up to one third of the total soil carbon reservoir (Gorham, 1991;Turunen et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Contrasting carbon dioxide fluxes between a drying shrub wetland in Northern Wisconsin, USA, and nearby forests

et al. 2009

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Abstract. Wetland biogeochemistry is strongly influenced by water and temperature dynamics, and these interactions are currently poorly represented in ecosystem and climate models. A decline in water table of approximately 30 cm was observed at a wetland in Northern Wisconsin, USA over a period from 2001-2007, which was highly correlated with an increase in daily soil temperature variability. Eddy covariance measurements of carbon dioxide exchange were compared with measured CO 2 fluxes at two nearby forests in order to distinguish wetland effects from regional trends. As wetland water table declined, both ecosystem respiration and ecosystem production increased by over 20% at the wetland, while forest CO 2 fluxes had no significant trends. Net ecosystem exchange of carbon dioxide at the wetland was not correlated with water table, but wetland evapotranspiration decreased substantially as the water table declined. These results suggest that changes in hydrology may not have a large impact on shrub wetland carbon balance over inter-annual time scales due to opposing responses in both ecosystem respiration and productivity.

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“…Therefore, R eco could be firstly obtained by the exponential function (Eq. (2)), in order to separate diurnal NEE into photosynthetic and respiratory fluxes (Saito et al 2005;Glenn et al 2006;Alberto et al 2009;Schedlbauer et al 2010).…”

Section: Flux Gap Fillingmentioning

confidence: 99%

Environmental Controls on Net Ecosystem CO2 Exchange Over a Reed (Phragmites australis) Wetland in the Yellow River Delta, China

Han

Yang

et al. 2012

Estuaries and Coasts

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Using the Eddy Covariance (EC) technique, we analyzed temporal variation in net ecosystem CO 2 exchange (NEE) and determined the effects of environmental factors on the balance between ecosystem photosynthesis and respiration in a reed (Phragmites australis) wetland in the Yellow River Delta, China. Our results indicated that diurnal and seasonal patterns of NEE and its components (ecosystem respiration (R eco ), gross primary production (GPP)) varied markedly among months for the growing season (May to October). The cumulative CO 2 emission was 1,657 g CO 2 m . The ratio of R eco to GPP in reed wetland was 0.68, which was close to other temperate wetlands. Soil temperature and soil moisture exerted the primary controls on R eco during the growing season. Daytime NEE values during the growing season were strongly correlated with photosynthetically active radiation. Aboveground biomass showed significant linear relationships with 24-h average NEE, daytime GPP, and R eco , respectively. Thus, we conclude that the coastal wetland acted as a carbon sink during the growing season despite the variations in environmental conditions, and long-term flux measurements over these ecosystems are undoubtedly necessary.

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Comparison of net ecosystem CO2 exchange in two peatlands in western Canada with contrasting dominant vegetation, Sphagnum and Carex

Cited by 70 publications

References 61 publications

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

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

Contrasting carbon dioxide fluxes between a drying shrub wetland in Northern Wisconsin, USA, and nearby forests

Environmental Controls on Net Ecosystem CO2 Exchange Over a Reed (Phragmites australis) Wetland in the Yellow River Delta, China

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