scholarly journals Calibrating a wetland methane emission model with hierarchical modeling and adaptive MCMC

2017 ◽  
Author(s):  
Jouni Susiluoto ◽  
Maarit Raivonen ◽  
Leif Backman ◽  
Marko Laine ◽  
Jarmo Mäkelä ◽  
...  
Keyword(s):  
Gas Transport ◽  
Hierarchical Modeling ◽  
Measurement Data ◽  
Flux Measurement ◽  
Ch4 Emission ◽  
Ch4 Oxidation ◽  
Adaptive Mcmc ◽  
Measurement Site ◽  
Ch4 Production ◽  
Plant Transport

Abstract. Methane (CH4) emission estimation for natural wetlands is complex and the estimates contain large uncertainties. The models used for the task are typically heavily parametrized and the parameter values are not well known. In this study we perform a Bayesian model calibration for a new wetland CH4 model to improve quality of the predictions and to understand the limitations of such models. The detailed process model that we analyze contains descriptions for CH4 production from anaerobic respiration, CH4 oxidation, and gas transportation by diffusion, ebullition, and the aerenchyma cells of vascular plants. The processes are controlled by several tunable parameters. We use a hierarchical statistical model to describe the parameters and obtain the posterior distributions of the parameters and uncertainties in the processes with adaptive MCMC techniques. For the estimation, the analysis utilizes measurement data from the Siikaneva flux measurement site in Southern Finland. The model parameters are calibrated using six different modeled peat column depths, and the hierarchical modeling allows us to assess the effect of the parameters on an annual basis. The results of the calibration and their cross validation suggest that the early spring net primary production and soil temperatures could be used to predict the annual methane emissions. The modeled peat column depth has an effect on how much the plant transport pathway dominates the gas transport, and the optimization moved most of the gas transport from the diffusive pathway to plant transport. This is in line with other research, highlighting the usefulness of algorithmic calibration of biogeochemical models. Modeling only 70 cm of the peat column gives the best flux estimates at the flux measurement site, while the estimates are worse for a column deeper than one meter or shallower than 50 cm. The posterior parameter distributions depend on the modeled peat depth. At the process level, the flux measurement data is able to constrain CH4 production and gas transport processes, but for CH4 oxidation, which is an important constituent of the total CH4 emission, the determining parameter is not identifiable.

scholarly journals Calibrating the sqHIMMELI v1.0 wetland methane emission model with hierarchical modeling and adaptive MCMC

2018 ◽  
Vol 11 (3) ◽  
pp. 1199-1228 ◽  
Author(s):  
Jouni Susiluoto ◽  
Maarit Raivonen ◽  
Leif Backman ◽  
Marko Laine ◽  
Jarmo Makela ◽  
...  
Keyword(s):  
Methane Emission ◽  
Process Model ◽  
Hierarchical Modeling ◽  
Net Primary Production ◽  
Measurement Data ◽  
Flux Measurement ◽  
Transport Processes ◽  
Emission Model ◽  
Ch4 Production ◽  
Emission Models

Abstract. Estimating methane (CH4) emissions from natural wetlands is complex, and the estimates contain large uncertainties. The models used for the task are typically heavily parameterized and the parameter values are not well known. In this study, we perform a Bayesian model calibration for a new wetland CH4 emission model to improve the quality of the predictions and to understand the limitations of such models.The detailed process model that we analyze contains descriptions for CH4 production from anaerobic respiration, CH4 oxidation, and gas transportation by diffusion, ebullition, and the aerenchyma cells of vascular plants. The processes are controlled by several tunable parameters. We use a hierarchical statistical model to describe the parameters and obtain the posterior distributions of the parameters and uncertainties in the processes with adaptive Markov chain Monte Carlo (MCMC), importance resampling, and time series analysis techniques. For the estimation, the analysis utilizes measurement data from the Siikaneva flux measurement site in southern Finland. The uncertainties related to the parameters and the modeled processes are described quantitatively. At the process level, the flux measurement data are able to constrain the CH4 production processes, methane oxidation, and the different gas transport processes. The posterior covariance structures explain how the parameters and the processes are related. Additionally, the flux and flux component uncertainties are analyzed both at the annual and daily levels. The parameter posterior densities obtained provide information regarding importance of the different processes, which is also useful for development of wetland methane emission models other than the square root HelsinkI Model of MEthane buiLd-up and emIssion for peatlands (sqHIMMELI). The hierarchical modeling allows us to assess the effects of some of the parameters on an annual basis. The results of the calibration and the cross validation suggest that the early spring net primary production could be used to predict parameters affecting the annual methane production. Even though the calibration is specific to the Siikaneva site, the hierarchical modeling approach is well suited for larger-scale studies and the results of the estimation pave way for a regional or global-scale Bayesian calibration of wetland emission models.

scholarly journals Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland

2018 ◽  
Vol 15 (3) ◽  
pp. 885-903 ◽  
Author(s):  
Sina Berger ◽  
Leandra S. E. Praetzel ◽  
Marie Goebel ◽  
Christian Blodau ◽  
Klaus-Holger Knorr
Keyword(s):  
Carbon Cycling ◽  
Pore Water ◽  
Water Reservoir ◽  
Water Level Fluctuations ◽  
Ch4 Emission ◽  
Nutrient Input ◽  
Ch4 Oxidation ◽  
Ch4 Production ◽  
In Situ Conditions

Abstract. Peatlands play an important role in global carbon cycling, but their responses to long-term anthropogenically changed hydrologic conditions and nutrient infiltration are not well known. While experimental manipulation studies, e.g., fertilization or water table manipulations, exist on the plot scale, only few studies have addressed such factors under in situ conditions. Therefore, an ecological gradient from the center to the periphery of a continental Canadian peatland bordering a eutrophic water reservoir, as reflected by increasing nutrient input, enhanced water level fluctuations, and increasing coverage of vascular plants, was used for a case study of carbon cycling along a sequence of four differently altered sites. We monitored carbon dioxide (CO2) and methane (CH4) surface fluxes and dissolved inorganic carbon (DIC) and CH4 concentrations in peat profiles from April 2014 through September 2015. Moreover, we studied bulk peat and pore-water quality and we applied δ13C–CH4 and δ13C–CO2 stable isotope abundance analyses to examine dominant CH4 production and emission pathways during the growing season of 2015. We observed differential responses of carbon cycling at the four sites, presumably driven by abundances of plant functional types and vicinity to the reservoir. A shrub-dominated site in close vicinity to the reservoir was a comparably weak sink for CO2 (in 1.5 years: −1093 ± 794, in 1 year: +135 ± 281 g CO2 m−2; a net release) as compared to two graminoid-moss-dominated sites and a moss-dominated site (in 1.5 years: −1552 to −2260 g CO2 m−2, in 1 year: −896 to −1282 g CO2 m−2). Also, the shrub-dominated site featured notably low DIC pore-water concentrations and comparably 13C-enriched CH4 (δ13C– CH4: −57.81 ± 7.03 ‰) and depleted CO2 (δ13C–CO2: −15.85 ± 3.61 ‰) in a more decomposed peat, suggesting a higher share of CH4 oxidation and differences in predominant methanogenic pathways. In comparison to all other sites, the graminoid-moss-dominated site in closer vicinity to the reservoir featured a ∼ 30 % higher CH4 emission (in 1.5 years: +61.4 ± 32, in 1 year: +39.86 ± 16.81 g CH4 m−2). Low δ13C–CH4 signatures (−62.30 ± 5.54 ‰) indicated only low mitigation of CH4 emissions by methanotrophic activity here. Pathways of methanogenesis and methanotrophy appeared to be related to the vicinity to the water reservoir: the importance of acetoclastic CH4 production apparently increased toward the reservoir, whereas the importance of CH4 oxidation increased toward the peatland center. Plant-mediated transport was the prevailing CH4 emission pathway at all sites even where graminoids were rare. Our study thus illustrates accelerated carbon cycling in a strongly altered peatland with consequences for CO2 and CH4 budgets. However, our results suggest that long-term excess nutrient input does not necessarily lead to a loss of the peatland carbon sink function.

Case study on effects of water management and rice straw incorporation in rice fields on production, oxidation, and emission of methane during fallow and following rice seasons

Soil Research ◽  
2011 ◽  
Vol 49 (3) ◽  
pp. 238 ◽  
Author(s):  
G. B. Zhang ◽  
Y. Ji ◽  
J. Ma ◽  
H. Xu ◽  
Z. C. Cai
Keyword(s):  
Water Management ◽  
Rice Straw ◽  
Block Design ◽  
Rice Fields ◽  
Ch4 Emission ◽  
Ch4 Oxidation ◽  
Ch4 Production ◽  
Significant Difference ◽  
Rice Season ◽  
Straw Incorporation

To investigate production, oxidation, and emission of methane (CH4) in rice fields during the fallow and following rice seasons as affected by water management and rice straw incorporation in the fallow season, field and incubation experiments were carried out from November 2007 to November 2008. Four treatments, i.e. two water managements (flooded and drained) and two rates of rice straw application (0 and 4.8 t/ha), were laid out in a randomised block design. Results show that obvious CH4 production occurred in flooded fields in the late fallow season; consequently, fallow CH4 emission contributed 9.6–33.1% to the annual total emission. However, emission mainly occurred during the rice season. During the rice season, the mean CH4 production potential in flooded fields was 2.6–3.8 times that in drained fields, making the total CH4 emission 2.1–2.5 times that in drained fields. Rice straw incorporated in flooded fields significantly increased production and emission of CH4 during both the fallow and the following rice seasons (P < 0.05), but in drained fields, no significant effect was observed (P > 0.05). There was no significant difference in mean CH4 oxidation potential between the treatments (P > 0.05), indicating that water management and rice straw incorporation in the fallow season have little influence on CH4 oxidation during the fallow and following rice seasons. Based on the findings, water management and rice straw incorporation in the fallow season significantly affected CH4 emission during the fallow and the following rice seasons by influencing CH4 production rather than CH4 oxidation in fields.

scholarly journals Climate Change and Goat Production: Enteric Methane Emission and Its Mitigation

Animals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 235 ◽  
Author(s):  
Pratap Pragna ◽  
Surinder S. Chauhan ◽  
Veerasamy Sejian ◽  
Brian J. Leury ◽  
Frank R. Dunshea
Keyword(s):  
Global Warming ◽  
Heat Stress ◽  
Management Strategies ◽  
Climate Scenario ◽  
Rumen Fermentation ◽  
Ch4 Emission ◽  
Changing Climate ◽  
Ch4 Production ◽  
Enteric Methane ◽  
The Impact

The ability of an animal to cope and adapt itself to the changing climate virtually depends on the function of rumen and rumen inhabitants such as bacteria, protozoa, fungi, virus and archaea. Elevated ambient temperature during the summer months can have a significant influence on the basic physiology of the rumen, thereby affecting the nutritional status of the animals. Rumen volatile fatty acid (VFA) production decreases under conditions of extreme heat. Growing recent evidence suggests there are genetic variations among breeds of goats in the impact of heat stress on rumen fermentation pattern and VFA production. Most of the effects of heat stress on rumen fermentation and enteric methane (CH4) emission are attributed to differences in the rumen microbial population. Heat stress-induced rumen function impairment is mainly associated with an increase in Streptococcus genus bacteria and with a decrease in the bacteria of Fibrobactor genus. Apart from its major role in global warming and greenhouse effect, enteric CH4 is also considered as a dietary energy loss in goats. These effects warrant mitigating against CH4 production to ensure optimum economic return from goat farming as well as to reduce the impact on global warming as CH4 is one of the more potent greenhouse gases (GHG). The various strategies that can be implemented to mitigate enteric CH4 emission include nutritional interventions, different management strategies and applying advanced biotechnological tools to find solution to reduce CH4 production. Through these advanced technologies, it is possible to identify genetically superior animals with less CH4 production per unit feed intake. These efforts can help the farming community to sustain goat production in the changing climate scenario.

scholarly journals SOIL CONTROLLING FACTORS OF METHANE GAS PRODUCTION FROM FLOODED RICE FIELDS IN PATI DISTRICT, CENTRAL JAVA

2016 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
P. Setyanto ◽  
Rosenani A.B. ◽  
A.K. Makarim ◽  
Che Fauziah I. ◽  
A. Bidin ◽  
...  
Keyword(s):  
Great Influence ◽  
Gas Production ◽  
Rice Fields ◽  
Limiting Factors ◽  
Stepwise Multiple Regression ◽  
Ch4 Emission ◽  
Atmospheric Methane ◽  
Production Potential ◽  
Central Java ◽  
Ch4 Production

Atmospheric methane (CH4) is recognized as one of the most important greenhouse gases. Methane, with some 15-30 times greater infrared-absorbing capability than CO2 on a mass basis, may account for 20% of anticipated global warming. Soils are one of the key factors, which play an important role in CH4 production and emission. However, data on CH4 emission from different soil types and the characteristics affecting CH4 production are lacking when compared to data on agronomic practices. This study was conducted to investigate the potential of CH4 production of selected soils in Java, and determine the limiting factors of CH4 production. The results showed that addition of 1% glucose to the soils led to an increase in CH4 production by more than twelve fold compared to no glucose addition. The CH4 production potential ranged between 3.21 and 112.30 mg CH4 kg-1 soil. The lowest CH4 production potential occurred in brown-grayish Grumosol, while the highest was in dark-gray Grumosol. Chemical and physical properties of the soils have great influence on CH4 production. Stepwise multiple regression analysis of CH4 production and soil characteristics showed that pH and the contents of Fe2O3, MnO2, SO4, and silt in the soil strongly influenced CH4 production. Results of this study can be used for further development of a model on CH4 emission from rice fields.

scholarly journals SOIL CONTROLLING FACTORS OF METHANE GAS PRODUCTION FROM FLOODED RICE FIELDS IN PATI DISTRICT, CENTRAL JAVA

2016 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
P. Setyanto ◽  
Rosenani A.B. ◽  
A.K. Makarim ◽  
Che Fauziah I. ◽  
A. Bidin ◽  
...  
Keyword(s):  
Great Influence ◽  
Gas Production ◽  
Rice Fields ◽  
Limiting Factors ◽  
Stepwise Multiple Regression ◽  
Ch4 Emission ◽  
Atmospheric Methane ◽  
Production Potential ◽  
Central Java ◽  
Ch4 Production

Atmospheric methane (CH4) is recognized as one of the most important greenhouse gases. Methane, with some 15-30 times greater infrared-absorbing capability than CO2 on a mass basis, may account for 20% of anticipated global warming. Soils are one of the key factors, which play an important role in CH4 production and emission. However, data on CH4 emission from different soil types and the characteristics affecting CH4 production are lacking when compared to data on agronomic practices. This study was conducted to investigate the potential of CH4 production of selected soils in Java, and determine the limiting factors of CH4 production. The results showed that addition of 1% glucose to the soils led to an increase in CH4 production by more than twelve fold compared to no glucose addition. The CH4 production potential ranged between 3.21 and 112.30 mg CH4 kg-1 soil. The lowest CH4 production potential occurred in brown-grayish Grumosol, while the highest was in dark-gray Grumosol. Chemical and physical properties of the soils have great influence on CH4 production. Stepwise multiple regression analysis of CH4 production and soil characteristics showed that pH and the contents of Fe2O3, MnO2, SO4, and silt in the soil strongly influenced CH4 production. Results of this study can be used for further development of a model on CH4 emission from rice fields.

scholarly journals Multi-year effect of wetting on CH<sub>4</sub> flux at taiga–tundra boundary in northeastern Siberia deduced from stable isotope ratios of CH<sub>4</sub>

2019 ◽  
Vol 16 (3) ◽  
pp. 755-768 ◽  
Author(s):  
Ryo Shingubara ◽  
Atsuko Sugimoto ◽  
Jun Murase ◽  
Go Iwahana ◽  
Shunsuke Tei ◽  
...  
Keyword(s):  
Water Saturation ◽  
Methane Flux ◽  
Interannual Variations ◽  
Ch4 Emission ◽  
Ch4 Flux ◽  
Ch4 Production ◽  
Year Effect ◽  
Northeastern Siberia ◽  
Order Of Magnitude ◽  
Acetoclastic Methanogenesis

Abstract. The response of CH4 emission from natural wetlands due to meteorological conditions is important because of its strong greenhouse effect. To understand the relationship between CH4 flux and wetting, we observed interannual variations in chamber CH4 flux, as well as the concentration, δ13C, and δD of dissolved CH4 during the summer from 2009 to 2013 at the taiga–tundra boundary in the vicinity of Chokurdakh (70∘37′ N, 147∘55′ E), located on the lowlands of the Indigirka River in northeastern Siberia. We also conducted soil incubation experiments to interpret δ13C and δD of dissolved CH4 and to investigate variations in CH4 production and oxidation processes. Methane flux showed large interannual variations in wet areas of sphagnum mosses and sedges (36–140 mg CH4 m−2 day−1 emitted). Increased CH4 emission was recorded in the summer of 2011 when a wetting event with extreme precipitation occurred. Although water level decreased from 2011 to 2013, CH4 emission remained relatively high in 2012, and increased further in 2013. Thaw depth became deeper from 2011 to 2013, which may partly explain the increase in CH4 emission. Moreover, dissolved CH4 concentration rose sharply by 1 order of magnitude from 2011 to 2012, and increased further from 2012 to 2013. Large variations in δ13C and δD of dissolved CH4 were observed in 2011, and smaller variations were seen in 2012 and 2013, suggesting both enhancement of CH4 production and less significance of CH4 oxidation relative to the larger pool of dissolved CH4. These multi-year effects of wetting on CH4 dynamics may have been caused by continued soil reduction across multiple years following the wetting. Delayed activation of acetoclastic methanogenesis following soil reduction could also have contributed to the enhancement of CH4 production. These processes suggest that duration of water saturation in the active layer can be important for predicting CH4 emission following a wetting event in the permafrost ecosystem.

Feeding lucerne silage to beef cattle at three allowances and four feeding frequencies affects circadian patterns of methane emissions, but not emissions per unit of intake

2014 ◽  
Vol 54 (9) ◽  
pp. 1350 ◽  
Author(s):  
Arjan Jonker ◽  
German Molano ◽  
Christopher Antwi ◽  
Garry Waghorn
Keyword(s):  
Emission Rate ◽  
Circadian Variation ◽  
Emission Rates ◽  
Ch4 Emission ◽  
Feeding Frequency ◽  
Ch4 Emissions ◽  
Time To Peak ◽  
Ch4 Production ◽  
Ad Libitum ◽  
Circadian Patterns

The objective of this study was to determine the circadian variation in methane (CH4) emissions from cattle fed lucerne silage at different feeding levels and feeding frequencies, to assist with interpretation of short ‘snapshot’ CH4 measurements used for predicting daily emissions. Eight Hereford × Friesian heifers (initially 20 months of age) were used in five consecutive periods (P1–5) of 14 days with CH4 emissions measured using respiration chambers for two consecutive days at the end of each period. Feed was restricted to intakes of ~6, 8, 8, 8 and 11 ± 1.3 (ad libitum) kg lucerne silage dry matter (DM), fed in 2, 2, 3, 4 or ad libitum (refilled twice daily) meals per day in P1–5, respectively. Daily CH4 production (g/day) was lower in P1 than in P2–4 (P < 0.05), which were lower than in P5 (P < 0.05), but CH4 yield (24.3 ± 1.23 g/kg DM) was unaffected by treatment. Among the five periods, CH4 emission rate (g/h) before feeding ranged from 1.8 to 6.5 g/h, time to peak CH4 production after start of feeding ranged from 19 to 40 min and peak CH4 production rate ranged from 11.1 to 17.5 g/h. The range in hourly CH4 emission rates during the day decreased with increasing feed intake level, but was unaffected by feeding frequency. In summary, the circadian pattern of CH4 emissions was affected by feed allowance and feeding frequency, and variation in CH4 emission rate was reduced with increasing intake, without affecting average daily yield (g CH4/kg DM intake).

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