Slippage and viscosity predictions in carbon micropores and their influence on CO2 and CH4 transport

2013 ◽  
Vol 138 (6) ◽  
pp. 064705 ◽  
Author(s):  
Mahnaz Firouzi ◽  
Jennifer Wilcox
Keyword(s):  
Ch4 Transport

scholarly journals Sensitivity analysis of a wetland methane emission model based on temperate and arctic wetland sites

2009 ◽  
Vol 6 (12) ◽  
pp. 3035-3051 ◽  
Author(s):  
J. van Huissteden ◽  
A. M. R. Petrescu ◽  
D. M. D. Hendriks ◽  
K. T. Rebel
Keyword(s):  
Temporal Variability ◽  
Global Scale ◽  
Transport Processes ◽  
Small Scale ◽  
Soil Parameters ◽  
Wetland Soil ◽  
Emission Model ◽  
Ch4 Emission ◽  
Model Based ◽  
Ch4 Transport

Abstract. Modelling of wetland CH4 fluxes using wetland soil emission models is used to determine the size of this natural source of CH4 emission on local to global scale. Most process models of CH4 formation and soil-atmosphere CH4 transport processes operate on a plot scale. For large scale emission modelling (regional to global scale) upscaling of this type of model requires thorough analysis of the sensitivity of these models to parameter uncertainty. We applied the GLUE (Generalized Likelihood Uncertainty Analysis) methodology to a well-known CH4 emission model, the Walter-Heimann model, as implemented in the PEATLAND-VU model. The model is tested using data from two temperate wetland sites and one arctic site. The tests include experiments with different objective functions, which quantify the fit of the model results to the data. The results indicate that the model 1) in most cases is capable of estimating CH4 fluxes better than an estimate based on the data avarage, but does not clearly outcompete a regression model based on local data; 2) is capable of reproducing larger scale (seasonal) temporal variability in the data, but not the small-scale (daily) temporal variability; 3) is not strongly sensitive to soil parameters, 4) is sensitive to parameters determining CH4 transport and oxidation in vegetation, and the temperature sensitivity of the microbial population. The GLUE method also allowed testing of several smaller modifications of the original model. We conclude that upscaling of this plot-based wetland CH4 emission model is feasible, but considerable improvements of wetland CH4 modelling will result from improvement of wetland vegetation data.

scholarly journals Contribution of recent plant photosynthates of <i>Eriophorum vaginatum</i> and <i>Scheuchzeria palustris</i> to methanogenesis and CH<sub>4</sub> transport at a boreal mire: a <sup>14</sup>C pulse-labeling study

2011 ◽  
Vol 8 (3) ◽  
pp. 4359-4389
Author(s):  
M. Dorodnikov ◽  
K.-H. Knorr ◽  
Y. Kuzyakov ◽  
M. Wilmking
Keyword(s):  
Plant Species ◽  
Plant Biomass ◽  
Vascular Plant ◽  
Eriophorum Vaginatum ◽  
Ch4 Flux ◽  
Ch4 Production ◽  
Scheuchzeria Palustris ◽  
Species Specific ◽  
Ch4 Transport

Abstract. Contribution of recent photosynthates to methanogenesis and plant-mediated methane (CH4) transport were studied on two dominating vascular plant species – Eriophorum vaginatum and Scheuchzeria palustris – at three microform types (hummocks, lawns and hollows) of a boreal natural minerogenic, oligotrophic fen in Eastern Finland. Measurements of total CH4 flux, isolation of shoots from entire peat and 14C-pulse labeling of mesocosms under controlled conditions allowed estimation of plant-mediated CH4 flux and contribution of recent (14C) photosynthates to total CH4. The obtained results showed (i) CH4 flux increases in the order E. hummocks ≤ E. lawns < S. hollows corresponding to the increasing water table level of the microforms as derived from in situ measurements. (ii) Plant-mediated CH4 flux accounted for 38, 31 and 51 % of total CH4 at E. hummocks, E. lawns and S. hollows, respectively. (iii) Contribution of recent photosynthates to methanogenesis accounted for 0.03 % for E. hummocks, 0.06 % for E. lawns and 0.13 % for S. hollows of assimilated 14C. Thus, S. palustris microsites are characterized by a higher efficiency for transporting CH4 from the peat column to the atmosphere when compared to E. vaginatum of drier lawns and hummocks. Contribution of recent plant photosynthates to methanogenesis was not depended on the amount of plant biomass: smaller S. palustris had higher 14CH4 as compared to larger E. vaginatum. Therefore, for the assessment of CH4 production and emission over meso- and macroscales as well as for the implication and development of C modeling of CH4 fluxes, it is necessary to account for plant species-specific processes including CH4 production, consumption and transportation and the attribution of those species to topographic microforms.

scholarly journals LAKE 2.0: a model for temperature, methane, carbon dioxide and oxygen dynamics in lakes

2016 ◽  
Vol 9 (5) ◽  
pp. 1977-2006 ◽  
Author(s):  
Victor Stepanenko ◽  
Ivan Mammarella ◽  
Anne Ojala ◽  
Heli Miettinen ◽  
Vasily Lykosov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Gas Dynamics ◽  
Gas Transfer ◽  
Property A ◽  
Prognostic Variables ◽  
Data Set ◽  
One Dimensional ◽  
D Model ◽  
Oxygen Dynamics ◽  
Ch4 Transport

Abstract. A one-dimensional (1-D) model for an enclosed basin (lake) is presented, which reproduces temperature, horizontal velocities, oxygen, carbon dioxide and methane in the basin. All prognostic variables are treated in a unified manner via a generic 1-D transport equation for horizontally averaged property. A water body interacts with underlying sediments. These sediments are represented by a set of vertical columns with heat, moisture and CH4 transport inside. The model is validated vs. a comprehensive observational data set gathered at Kuivajärvi Lake (southern Finland), demonstrating a fair agreement. The value of a key calibration constant, regulating the magnitude of methane production in sediments, corresponded well to that obtained from another two lakes. We demonstrated via surface seiche parameterization that the near-bottom turbulence induced by surface seiches is likely to significantly affect CH4 accumulation there. Furthermore, our results suggest that a gas transfer through thermocline under intense internal seiche motions is a bottleneck in quantifying greenhouse gas dynamics in dimictic lakes, which calls for further research.

scholarly journals Plant-mediated CH<sub>4</sub> transport and contribution of photosynthates to methanogenesis at a boreal mire: a <sup>14</sup>C pulse-labeling study

2011 ◽  
Vol 8 (8) ◽  
pp. 2365-2375 ◽  
Author(s):  
M. Dorodnikov ◽  
K.-H. Knorr ◽  
Y. Kuzyakov ◽  
M. Wilmking
Keyword(s):  
Plant Species ◽  
Plant Biomass ◽  
Vascular Plant ◽  
Species Level ◽  
Ch4 Flux ◽  
Ch4 Production ◽  
Scheuchzeria Palustris ◽  
Species Specific ◽  
Ch4 Transport ◽  
Eastern Finland

Abstract. Plant-mediated methane (CH4) transport and the contribution of recent photosynthates to methanogenesis were studied on two dominating vascular plant species – Eriophorum vaginatum and Scheuchzeria palustris – at three types of microrelief forms (hummocks – E. hummocks, lawns – E. lawns and hollows – S. hollows) of a boreal natural minerogenic, oligotrophic fen in Eastern Finland. 14C-pulse labeling of mesocosms with shoots isolated from entire belowground peat under controlled conditions allowed estimation of plant-mediated CH4 flux and contribution of recent (14C) photosynthates to total CH4. The results showed (i) CH4 flux increased in the order E. hummocks ≤ E. lawns < S. hollows corresponding to the increasing water table level at the relief microforms as adjusted to field conditions. (ii) Plant-mediated CH4 flux accounted for 38, 31 and 51 % of total CH4 at E. hummocks, E. lawns and S. hollows, respectively. (iii) Contribution of recent photosynthates to methanogenesis accounted for 0.03 % for E. hummocks, 0.06 % for E. lawns and 0.13 % for S.hollows of assimilated 14C. Thus, microsites with S. palustris were characterized by higher rates of transported CH4 from the peat column to the atmosphere when compared to E. vaginatum of drier lawns and hummocks. Contribution of recent photosynthates to methanogenesis was dependent on the plant biomass within-species level (E. vaginatum at hummocks and lawns) but was not observed between species: smaller S. palustris had higher flux of 14CH4 as compared to larger E. vaginatum. Therefore, for the assessment of CH4 dynamics over meso- and macroscale as well as for the implication and development of the modeling of CH4 fluxes, it is necessary to account for plant species-specific differences in CH4 production, consumption and transport and the attribution of those species to topographic forms of microrelief.

scholarly journals Dissolved CH<sub>4</sub> coupled to Photosynthetic Picoeukaryotes in Oxic Waters and Cumulative Chlorophyll-a in Anoxia

2020 ◽  
Author(s):  
Elizabeth León-Palmero ◽  
Alba Contreras-Ruiz ◽  
Ana Sierra ◽  
Rafael Morales-Baquero ◽  
Isabel Reche
Keyword(s):  
Organic Carbon ◽  
Chlorophyll A ◽  
Aquatic Ecosystems ◽  
Methanogenic Archaea ◽  
Climatic Forcing ◽  
Anoxic Waters ◽  
Ch4 Concentration ◽  
The Mean ◽  
Dissolved Ch4 Concentration ◽  
Ch4 Transport

Abstract. CH4 emissions from reservoirs are responsible for the majority of the atmospheric climatic forcing of these aquatic ecosystems, comparable to emissions from paddies or biomass burning. Primarily, CH4 is produced during the anaerobic mineralization of organic carbon in the anoxic sediments by methanogenic archaea. However, the origin of the recurrent and ubiquitous CH4 supersaturation in oxic waters (i.e., methane paradox) is still controversial. Here, we determined the dissolved CH4 concentration in the water column of twelve reservoirs during the summer stratification and the winter mixing. We obtained that the dissolved CH4 concentration varied up to four orders of magnitude (0.02–213.64 μM), and all depths were consistently supersaturated (710–7082234 %) in both periods. Phytoplanktonic sources of carbon appear to determine the concentration of CH4 in the reservoirs. In the anoxic waters, the depth-cumulative chlorophyll-a concentration, a proxy for the total phytoplanktonic biomass exported to sediments, determined the CH4 concentration. In the oxic waters, the photosynthetic picoeukaryotes abundance significantly determined the dissolved CH4 concentration both during the stratification and the mixing. The mean depth of the reservoirs, as a surrogate of the CH4 transport from sediment to the oxic waters, also contributed in shallow systems. Our findings suggest that photosynthetic picoeukaryotes can have a significant role in determining the CH4 concentration in oxic waters and, in comparison to cyanobacteria, have been poorly explored as CH4 sources.

scholarly journals Sensitivity analysis of a wetland methane emission model based on temperate and Arctic wetland sites

2009 ◽  
Vol 6 (5) ◽  
pp. 9083-9126 ◽  
Author(s):  
J. van Huissteden ◽  
A. M. R. Petrescu ◽  
D. M. D. Hendriks ◽  
K. T. Rebel
Keyword(s):  
Temporal Variability ◽  
Global Scale ◽  
Transport Processes ◽  
Small Scale ◽  
Soil Parameters ◽  
Wetland Soil ◽  
Emission Model ◽  
Ch4 Emission ◽  
Model Based ◽  
Ch4 Transport

Abstract. Modelling of wetland CH4 fluxes using wetland soil emission models is used to determine the size of this natural source of CH4 emission on local to global scale. Most process models of CH4 formation and soil-atmosphere CH4 transport processes operate on a plot scale. For large scale emission modelling (regional to global scale) upscaling of this type of model requires thorough analysis of the sensitivity of these models to parameter uncertainty. We applied the GLUE (Generalized Likelihood Uncertainty Analysis) methodology to a well-known CH4 emission model, the Walter-Heimann model, as implemented in the PEATLAND-VU model. The model is tested using data from two temperate wetland sites and one arctic site. The tests include experiments with different objective functions, which quantify the fit of the model results to the data. The results indicate that the model 1) in most cases is capable of estimating CH4 fluxes better than an estimate based on the data avarage, but does not clearly outcompete a regression model based on local data; 2) is capable of reproducing larger scale (seasonal) temporal variability in the data, but not the small-scale (daily) temporal variability; 3) is not strongly sensitive to soil parameters, 4) is sensitive to parameters determining CH4 transport and oxidation in vegetation, and the temperature sensitivity of the microbial population. The GLUE method also allowed testing of several smaller modifications of the original model. We conclude that upscaling of this plot-based wetland CH4 emission model is feasible, but considerable improvements of wetland CH4 modelling will result from improvement of wetland vegetation data.

Plant-mediated CH4 transport and C gas dynamics quantified in-situ in a Phalaris arundinacea-dominant wetland

2011 ◽  
Vol 343 (1-2) ◽  
pp. 287-301 ◽  
Author(s):  
Louise Askaer ◽  
Bo Elberling ◽  
Thomas Friborg ◽  
Christian J. Jørgensen ◽  
Birger U. Hansen
Keyword(s):  
Gas Dynamics ◽  
Phalaris Arundinacea ◽  
Ch4 Transport

Carbon isotope fractionation during CH4 transport in paddy fields

2014 ◽  
Vol 57 (7) ◽  
pp. 1664-1670 ◽  
Author(s):  
GuangBin Zhang ◽  
Yang Ji ◽  
Gang Liu ◽  
Jing Ma ◽  
Hua Xu
Keyword(s):  
Carbon Isotope ◽  
Isotope Fractionation ◽  
Paddy Fields ◽  
Carbon Isotope Fractionation ◽  
Ch4 Transport
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