Controls on in situ oxygen and dissolved inorganic carbon dynamics in peats of a temperate fen

Estop‐Aragonés, Cristian; Knorr, Klaus‐Holger; Blodau, Christian

doi:10.1029/2011jg001888

Cited by 51 publications

(60 citation statements)

References 83 publications

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“…6). Such concentrations were only reached at larger sediment depth, though, and ongoing stripping of N 2 with ebullition may have raised concentration thresholds over time (Fechner-Levy and Hemond, 1996). At a remaining N 2 partial pressure of 0.5 atm, ebullition was not possible from a theoretical point of view, which may explain its limited importance in the pond.…”

Section: Spatial Pattern Of Ch 4 and Co 2 Fluxesmentioning

confidence: 93%

“…The probe was enclosed in CO 2 permeable silicone tubes, as already used by Estop-Aragonés et al (2012) in peats, and attached to a floating platform at a depth of approximately 18 cm and a distance of 3.2 m from the pond margin. In water equilibration time to 90 % of dissolved concentration was approximately 1 h when concentration increased but more delayed when it fell (Fig.…”

Section: Co 2 Concentration Measurements and Gradient Flux Calculationsmentioning

confidence: 99%

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Summer fluxes of methane and carbon dioxide from a pond and floating mat in a continental Canadian peatland

et al. 2016

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Abstract. Ponds smaller than 10 000 m2 likely account for about one-third of the global lake perimeter. The release of methane (CH4) and carbon dioxide (CO2) from these ponds is often high and significant on the landscape scale. We measured CO2 and CH4 fluxes in a temperate peatland in southern Ontario, Canada, in summer 2014 along a transect from the open water of a small pond (847 m2) towards the surrounding floating mat (5993 m2) and in a peatland reference area. We used a high-frequency closed chamber technique and distinguished between diffusive and ebullitive CH4 fluxes. CH4 fluxes and CH4 bubble frequency increased from a median of 0.14 (0.00 to 0.43) mmol m−2 h−1 and 4 events m−2 h−1 on the open water to a median of 0.80 (0.20 to 14.97) mmol m−2 h−1 and 168 events m−2 h−1 on the floating mat. The mat was a summer hot spot of CH4 emissions. Fluxes were 1 order of magnitude higher than at an adjacent peatland site. During daytime the pond was a net source of CO2 equivalents to the atmosphere amounting to 0.13 (−0.02 to 1.06) g CO2 equivalents m−2 h−1, whereas the adjacent peatland site acted as a sink of −0.78 (−1.54 to 0.29) g CO2 equivalents m−2 h−1. The photosynthetic CO2 uptake on the floating mat did not counterbalance the high CH4 emissions, which turned the floating mat into a strong net source of 0.21 (−0.11 to 2.12) g CO2 equivalents m−2 h−1. This study highlights the large small-scale variability of CH4 fluxes and CH4 bubble frequency at the peatland–pond interface and the importance of the often large ecotone areas surrounding small ponds as a source of greenhouse gases to the atmosphere.

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Section: Spatial Pattern Of Ch 4 and Co 2 Fluxesmentioning

confidence: 93%

Section: Co 2 Concentration Measurements and Gradient Flux Calculationsmentioning

confidence: 99%

Summer fluxes of methane and carbon dioxide from a pond and floating mat in a continental Canadian peatland

et al. 2016

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“…Rate of the CH 4 oxidation reaction depends on the concentrations of both CH 4 and O 2 (Watson et al, 1997) and since CH 4 oxidation is a biochemical reaction, the rate is also limited by factors that affect the microbial activity, such as temperature (Whalen and Reeburgh, 1996). When the WTD is low, the O 2 concentrations in the top peat layers are high, favoring CH 4 oxidation (Moore et al, 2011;Estop-Aragonés et al, 2012). However, there can be anoxic areas above the WTD (Silins and Rothwell, 1999;Fan et al, 2014) and the O 2 transported down by plant roots provides conditions suitable for methanotrophy also in the inundated peat layers (Fritz et al, 2011).…”

Section: Key Factors For Ch 4 Transport and Oxidationmentioning

confidence: 99%

“…Only in the case that the boundary of the extra layer would be closer than 1 cm to a boundary of the background layering, the WTD is rounded to this nearest permanent layer boundary. Strict division of the peat to air-filled and water-filled parts is a simplification since anoxic sites can occur above the WTD (Estop-Aragonés et al, 2012). However, as in sitelevel and larger-scale simulations, even an observation-based WTD is an approximate value over peatland areas, and we consider the strict division to anoxic and oxic parts a robust approach.…”

Section: Peat Geometry Root Distribution and Movement Of Watermentioning

confidence: 99%

“…In models, the peat column is commonly considered in a simplified way, assuming that the water table depth (WTD) forms a border below which the peat is saturated with water and above which peat pores are air filled. However, in reality, the division is not this strict, as VGC can be a considerable fraction of the total volume below the WTD, for instance, due to the gas production in the peat , and the peat can be wet above the WTD if the peat pores retain water when the WTD drops (Estop-Aragonés et al, 2012;Fan et al, 2014). Diffusion through the peat column is thought to be a minor component in the total CH 4 emissions of a peatland when gas-transporting vegetation is present at the site (Walter et al, 1996;Lai, 2009), because the diffusion coefficient in water is approximately 4 orders of magnitude lower than in gas (Staunton, 2008) and because the probability of CH 4 being consumed by methanotrophs is higher in the peat, especially when the WTD is low (Estop-Aragonés et al, 2012).…”

Section: Key Factors For Ch 4 Transport and Oxidationmentioning

confidence: 99%

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HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

et al. 2017

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Abstract. Wetlands are one of the most significant natural sources of methane (CH 4 ) to the atmosphere. They emit CH 4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH 4 , in addition to carbon dioxide (CO 2 ). Production of CH 4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH 4 emissions are thus needed for upscaling observations to estimate present CH 4 emissions and for producing scenarios of future atmospheric CH 4 concentrations. Aiming at a CH 4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH 4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH 4 , CO 2 , and oxygen (O 2 ) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH 4 -related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH 4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH 4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of Published by Copernicus Publications on behalf of the European Geosciences Union. 4666M. Raivonen et al.: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands the total CH 4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O 2 concentrations that affect the CH 4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH 4 emissions in this model version.

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Methanogen Biomarkers in the Discontinuous Permafrost Zone of Stordalen, Sweden

Lupascu

Wadham

Hornibrook

et al. 2014

Permafrost & Periglacial

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Permafrost peatlands are both an important source of atmospheric CH4 and a substantial sink for atmospheric CO2. Climate change can affect this balance, with higher temperatures resulting in the conversion of permafrost soils to wetlands and associated accelerated mineralisation and increased CH4 emission. To better understand the impact of such processes on methanogen populations, we investigated the anaerobic decay of soil carbon in a low Arctic, discontinuous permafrost peatland. Cores were collected monthly from sedge and Sphagnum mires in north Sweden during the summer of 2006. We determined CH4 concentrations and production potentials, together with variations in the size of the methanogenic community as indicated by concentrations of archaeal lipid biomarkers (phosphorylated archaeol, archaeol and hydroxyarchaeol). Concentrations of methanogen biomarkers generally were higher at the sedge site, increased with depth for all sites and months, and were usually below the detection limits in shallow (<10 cm) Sphagnum peat. The distribution of biomarkers reflects the strong influence of water table depth on anaerobic conditions and methanogen populations, while differences in biomarker concentrations can be explained by differences in vegetation cover and pH. However, methanogen populations inferred from biomarker data show a decoupling from in‐situ CH4 production over the season and from CH4 production potential, suggesting that other factors such as the availability of labile organic substrates can influence methanogen abundance. Archaeal lipid biomarkers appear to offer a potential new means to investigate permafrost biogeochemical processes but the interpretation of signals remains complex. Copyright © 2014 John Wiley & Sons, Ltd.

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Controls on in situ oxygen and dissolved inorganic carbon dynamics in peats of a temperate fen

Cited by 51 publications

References 83 publications

Summer fluxes of methane and carbon dioxide from a pond and floating mat in a continental Canadian peatland

Summer fluxes of methane and carbon dioxide from a pond and floating mat in a continental Canadian peatland

HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

Methanogen Biomarkers in the Discontinuous Permafrost Zone of Stordalen, Sweden

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