Significance of stomatal control on methane release from -dominated wetlands

Morrissey, L. A.; Zobel, Donald B.; Livingston, Gerald P.

doi:10.1016/0045-6535(93)90430-d

Cited by 97 publications

(66 citation statements)

References 28 publications

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“…This would be similar to rice (Oryza sativa), Menyanthes trifoliata, and J. effusus that release CH 4 from the stem or leaf sheath, possibly through micropores, not stomata (Nouchi et al, 1990;Macdonald et al, 1998;Hennenberg et al, 2012). However, in the studies by Schimel (1995) and Morrissey et al (1993), CH 4 seemed to exit the sedges through the leaf blades and stomata, and this would thus form the main resistance for the flux in the plant. Diurnal variation of the CH 4 emissions could indicate stomatal control but clear diurnal patterns have not been observed Jackowicz-Korczyński et al, 2010); the maximum emissions may even occur at night (Mikkelä et al, 1995;Waddington et al, 1996;Juutinen et al, 2004).…”

Section: Key Factors For Ch 4 Transport and Oxidationmentioning

confidence: 88%

“…Some aquatic plants transport O 2 actively through the aerenchyma with pressurized throughflow (Brix et al, 1996). As a byproduct, these mechanisms also transport CH 4 to the atmosphere (Morrissey et al, 1993;Brix et al, 1996). In addition to transfer via plants, CH 4 is known to be emitted from peatlands as ebullition, i.e., release of CH 4 bubbles into the atmosphere, and by diffusion through the peat column.…”

Section: Introductionmentioning

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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Section: Key Factors For Ch 4 Transport and Oxidationmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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“…In comparison, wetland CH 4 emissions were also reported to show daily maxima at daytime (e.g. Morrisey et al, 1993;Hendriks et al, 2010;Hatala Matthes et al, 2014), especially at sites with high abundance of vascular plants. No diurnal pattern (e.g.…”

Section: Diurnal Variability Of Ch 4 Emissionsmentioning

confidence: 99%

High net CO<sub>2</sub> and CH<sub>4</sub> release at a eutrophic shallow lake on a formerly drained fen

et al. 2016

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Abstract. Drained peatlands often act as carbon dioxide (CO 2 ) hotspots. Raising the groundwater table is expected to reduce their CO 2 contribution to the atmosphere and revitalise their function as carbon (C) sink in the long term. Without strict water management rewetting often results in partial flooding and the formation of spatially heterogeneous, nutrient-rich shallow lakes. Uncertainties remain as to when the intended effect of rewetting is achieved, as this specific ecosystem type has hardly been investigated in terms of greenhouse gas (GHG) exchange. In most cases of rewetting, methane (CH 4 ) emissions increase under anoxic conditions due to a higher water table and in terms of global warming potential (GWP) outperform the shift towards CO 2 uptake, at least in the short term.Based on eddy covariance measurements we studied the ecosystem-atmosphere exchange of CH 4 and CO 2 at a shallow lake situated on a former fen grassland in northeastern Germany. The lake evolved shortly after flooding, 9 years previous to our investigation period. The ecosystem consists of two main surface types: open water (inhabited by submerged and floating vegetation) and emergent vegetation (particularly including the eulittoral zone of the lake, dominated by Typha latifolia). To determine the individual contribution of the two main surface types to the net CO 2 and CH 4 exchange of the whole lake ecosystem, we combined footprint analysis with CH 4 modelling and net ecosystem exchange partitioning.The CH 4 and CO 2 dynamics were strikingly different between open water and emergent vegetation. Net CH 4 emissions from the open water area were around 4-fold higher than from emergent vegetation stands, accounting for 53 and 13 g CH 4 m −2 a −1 respectively. In addition, both surface types were net CO 2 sources with 158 and 750 g CO 2 m −2 a −1 respectively. Unusual meteorological conditions in terms of a warm and dry summer and a mild winter might have facilitated high respiration rates. In sum, even after 9 years of rewetting the lake ecosystem exhibited a considerable C loss and global warming impact, the latter mainly driven by high CH 4 emissions. We assume the eutrophic conditions in combination with permanent high inundation as major reasons for the unfavourable GHG balance.

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“…Many field studies have concluded that the presence of vascular plants with aerenchyma leads to increased net CH 4 emissions (Morrissey et al, 1993;Schimel, 1995;Chanton et al, 1993;Bartlett et al, 1992;Frenzel and Karofeld, 2000;Grunfeld and Brix, 1999;Torn and Chapin, 1993) by providing an efficient escape mechanism for CH 4 . However, in large-scale CH 4 biogeochemical models, separate representations of aerenchyma area (and the attendant diffusive pathway) and methanogenesis substrate inputs are required.…”

Section: Aerenchyma Impacts On Net Ch 4 Emissionsmentioning

confidence: 99%

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

et al. 2011

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Abstract. Terrestrial net CH 4 surface fluxes often represent the difference between much larger gross production and consumption fluxes and depend on multiple physical, biological, and chemical mechanisms that are poorly understood and represented in regional-and global-scale biogeochemical models. To characterize uncertainties, study feedbacks between CH 4 fluxes and climate, and to guide future model development and experimentation, we developed and tested a new CH 4 biogeochemistry model (CLM4Me) integrated in the land component (Community Land Model; CLM4) of the Community Earth System Model (CESM1). CLM4Me includes representations of CH 4 production, oxidation, aerenchyma transport, ebullition, aqueous and gaseous diffusion, and fractional inundation. As with most global models, CLM4 lacks important features for predicting current and future CH 4 fluxes, including: vertical representation of soil organic matter, accurate subgrid scale hydrology, realistic representation of inundated system vegetation, anaerobic decomposition, thermokarst dynamics, and aqueous chemistry. We compared the seasonality and magnitude of predicted CH 4 emissions to observations from 18 sites and three global atmospheric inversions. Simulated net CH 4 emissions using our baseline parameter set were 270, 160, 50, and 70 Tg CH 4 yr −1 globally, in the tropics, in the temperate zone, and north of 45 • N, respectively; these values are within the range of previous estimates. We then used the model to characterize the sensitivity of regional and global CH 4 emission estimates to uncertainties in model paCorrespondence to: W. J. Riley (wjriley@lbl.gov) rameterizations. Of the parameters we tested, the temperature sensitivity of CH 4 production, oxidation parameters, and aerenchyma properties had the largest impacts on net CH 4 emissions, up to a factor of 4 and 10 at the regional and gridcell scales, respectively. In spite of these uncertainties, we were able to demonstrate that emissions from dissolved CH 4 in the transpiration stream are small (<1 Tg CH 4 yr −1 ) and that uncertainty in CH 4 emissions from anoxic microsite production is significant. In a 21st century scenario, we found that predicted declines in high-latitude inundation may limit increases in high-latitude CH 4 emissions. Due to the high level of remaining uncertainty, we outline observations and experiments that would facilitate improvement of regional and global CH 4 biogeochemical models.

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Significance of stomatal control on methane release from -dominated wetlands

Cited by 97 publications

References 28 publications

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

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

High net CO<sub>2</sub> and CH<sub>4</sub> release at a eutrophic shallow lake on a formerly drained fen

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

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Significance of stomatal control on methane release from -dominated wetlands

Cited by 97 publications

References 28 publications

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

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

High net CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; release at a eutrophic shallow lake on a formerly drained fen

Barriers to predicting changes in global terrestrial methane fluxes: analyses using CLM4Me, a methane biogeochemistry model integrated in CESM

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High net CO<sub>2</sub> and CH<sub>4</sub> release at a eutrophic shallow lake on a formerly drained fen