scholarly journals Influence of elevated carbon dioxide concentrations on methane emission and its associated soil microflora in rice ecosystem

2021 ◽  
Vol 13 (SI) ◽  
pp. 26-34
Author(s):  
S. K. Rajkishore ◽  
M. Maheswari ◽  
K. S. Subramanian ◽  
R. Prabhu ◽  
G. Vanitha
Keyword(s):  
Elevated Co2 ◽  
Methane Emission ◽  
Methane Flux ◽  
Methane Emissions ◽  
Soil Microflora ◽  
Mitigation Strategies ◽  
Emission Rates ◽  
Randomized Design ◽  
Dry Soil ◽  
Rice Ecosystem

The dynamics of methane emission and its associated soil microflora in rice ecosystem as a response to elevated CO2 concentrations were studied in open top chamber (OTC) conditions. The treatments consisted of three levels of CO2 (396, 550 and 750 µmol mol-1) and three levels of nitrogen (0, 150 and 200 kg ha-1) and replicated five times in a completely randomized design. The data showed that elevated [CO2] significantly (P ? 0.01) increased the DOC throughout the cropping period with the values ranging from 533 to 722 mg L-1 and 368 to 501 mg L-1 in C750 and Camb, respectively. Methane emission rates were monitored regularly during the experiment period and it was revealed that elevated [CO2] had increased the methane emissions regardless of stages of crop growth.  It was observed that methane emissions were significantly higher under [CO2] of 750 µmol mol-1 by 33 to 54 per cent over the ambient [CO2] of 396 µmol mol-1. Consistent with the observed increases in methane flux, the enumeration of methanogens showed a significant (P ? 0.01) increase under elevated [CO2] with the population ranging from 5.7 to 20.1 x 104 CFU g-1 of dry soil and 5.1 to 16.9 x 104 CFU g-1 of dry soil under C750 and Camb concentrations, respectively. Interestingly, even though higher methanotrophs population was recorded under elevated [CO2], it could not circumvent the methane emission. Overall, the results of OTC studies suggest that methane mitigation strategies need to be explored for the future high CO2 environments. 

scholarly journals Methane transport from the active layer to lakes in the Arctic using Toolik Lake, Alaska, as a case study

2015 ◽  
Vol 112 (12) ◽  
pp. 3636-3640 ◽  
Author(s):  
Adina Paytan ◽  
Alanna L. Lecher ◽  
Natasha Dimova ◽  
Katy J. Sparrow ◽  
Fenix Garcia-Tigreros Kodovska ◽  
...  
Keyword(s):  
Global Warming ◽  
Active Layer ◽  
Lake Water ◽  
Large Fraction ◽  
Methane Flux ◽  
Methane Emissions ◽  
Arctic Lakes ◽  
The Arctic ◽  
Emission Rates ◽  
Toolik Lake

Methane emissions in the Arctic are important, and may be contributing to global warming. While methane emission rates from Arctic lakes are well documented, methods are needed to quantify the relative contribution of active layer groundwater to the overall lake methane budget. Here we report measurements of natural tracers of soil/groundwater, radon, and radium, along with methane concentration in Toolik Lake, Alaska, to evaluate the role active layer water plays as an exogenous source for lake methane. Average concentrations of methane, radium, and radon were all elevated in the active layer compared with lake water (1.6 × 104 nM, 61.6 dpm⋅m−3, and 4.5 × 105 dpm⋅m−3 compared with 1.3 × 102 nM, 5.7 dpm⋅m−3, and 4.4 × 103 dpm⋅m−3, respectively). Methane transport from the active layer to Toolik Lake based on the geochemical tracer radon (up to 2.9 g⋅m−2⋅y−1) can account for a large fraction of methane emissions from this lake. Strong but spatially and temporally variable correlations between radon activity and methane concentrations (r2 > 0.69) in lake water suggest that the parameters that control methane discharge from the active layer also vary. Warming in the Arctic may expand the active layer and increase the discharge, thereby increasing the methane flux to lakes and from lakes to the atmosphere, exacerbating global warming. More work is needed to quantify and elucidate the processes that control methane fluxes from the active layer to predict how this flux might change in the future and to evaluate the regional and global contribution of active layer water associated methane inputs.

Methane in Australian agriculture: current emissions, sources and sinks, and potential mitigation strategies

2015 ◽  
Vol 66 (1) ◽  
pp. 1 ◽  
Author(s):  
Damien Finn ◽  
Ram Dalal ◽  
Athol Klieve
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Plant Biomass ◽  
Methane Flux ◽  
Methane Emissions ◽  
Mitigation Strategies ◽  
Extreme Weather Events ◽  
Future Research ◽  
Sources And Sinks ◽  
Climate Change Drivers

Methane is a potent greenhouse gas with a global warming potential ~28 times that of carbon dioxide. Consequently, sources and sinks that influence the concentration of methane in the atmosphere are of great interest. In Australia, agriculture is the primary source of anthropogenic methane emissions (60.4% of national emissions, or 3 260 kt–1 methane year–1, between 1990 and 2011), and cropping and grazing soils represent Australia’s largest potential terrestrial methane sink. As of 2011, the expansion of agricultural soils, which are ~70% less efficient at consuming methane than undisturbed soils, to 59% of Australia’s land mass (456 Mha) and increasing livestock densities in northern Australia suggest negative implications for national methane flux. Plant biomass burning does not appear to have long-term negative effects on methane flux unless soils are converted for agricultural purposes. Rice cultivation contributes marginally to national methane emissions and this fluctuates depending on water availability. Significant available research into biological, geochemical and agronomic factors has been pertinent for developing effective methane mitigation strategies. We discuss methane-flux feedback mechanisms in relation to climate change drivers such as temperature, atmospheric carbon dioxide and methane concentrations, precipitation and extreme weather events. Future research should focus on quantifying the role of Australian cropping and grazing soils as methane sinks in the national methane budget, linking biodiversity and activity of methane-cycling microbes to environmental factors, and quantifying how a combination of climate change drivers will affect total methane flux in these systems.

scholarly journals Identification and characterization of high methane-emitting abandoned oil and gas wells

2016 ◽  
Vol 113 (48) ◽  
pp. 13636-13641 ◽  
Author(s):  
Mary Kang ◽  
Shanna Christian ◽  
Michael A. Celia ◽  
Denise L. Mauzerall ◽  
Markus Bill ◽  
...  
Keyword(s):  
Methane Emission ◽  
Oil And Gas ◽  
Methane Emissions ◽  
Gas Production ◽  
Mitigation Strategies ◽  
Gas Wells ◽  
Emission Data ◽  
Flow Rates ◽  
Abandoned Wells ◽  
Oil Gas

Recent measurements of methane emissions from abandoned oil/gas wells show that these wells can be a substantial source of methane to the atmosphere, particularly from a small proportion of high-emitting wells. However, identifying high emitters remains a challenge. We couple 163 well measurements of methane flow rates; ethane, propane, andn-butane concentrations; isotopes of methane; and noble gas concentrations from 88 wells in Pennsylvania with synthesized data from historical documents, field investigations, and state databases. Using our databases, we (i) improve estimates of the number of abandoned wells in Pennsylvania; (ii) characterize key attributes that accompany high emitters, including depth, type, plugging status, and coal area designation; and (iii) estimate attribute-specific and overall methane emissions from abandoned wells. High emitters are best predicted as unplugged gas wells and plugged/vented gas wells in coal areas and appear to be unrelated to the presence of underground natural gas storage areas or unconventional oil/gas production. Repeat measurements over 2 years show that flow rates of high emitters are sustained through time. Our attribute-based methane emission data and our comprehensive estimate of 470,000–750,000 abandoned wells in Pennsylvania result in estimated state-wide emissions of 0.04–0.07 Mt (1012g) CH4per year. This estimate represents 5–8% of annual anthropogenic methane emissions in Pennsylvania. Our methodology combining new field measurements with data mining of previously unavailable well attributes and numbers of wells can be used to improve methane emission estimates and prioritize cost-effective mitigation strategies for Pennsylvania and beyond.

scholarly journals A predictive algorithm for wetlands in deep time paleoclimate models

2019 ◽  
Vol 12 (4) ◽  
pp. 1351-1364 ◽  
Author(s):  
David J. Wilton ◽  
Marcus P. S. Badger ◽  
Euripides P. Kantzas ◽  
Richard D. Pancost ◽  
Paul J. Valdes ◽  
...  
Keyword(s):  
Methane Emission ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Grid Cell ◽  
Methane Flux ◽  
Early Eocene ◽  
Emission Rates ◽  
Deep Time ◽  
Vegetation Models

Abstract. Methane is a powerful greenhouse gas produced in wetland environments via microbial action in anaerobic conditions. If the location and extent of wetlands are unknown, such as for the Earth many millions of years in the past, a model of wetland fraction is required in order to calculate methane emissions and thus help reduce uncertainty in the understanding of past warm greenhouse climates. Here we present an algorithm for predicting inundated wetland fraction for use in calculating wetland methane emission fluxes in deep-time paleoclimate simulations. For each grid cell in a given paleoclimate simulation, the algorithm determines the wetland fraction predicted by a nearest-neighbour search of modern-day data in a space described by a set of environmental, climate and vegetation variables. To explore this approach, we first test it for a modern-day climate with variables obtained from observations and then for an Eocene climate with variables derived from a fully coupled global climate model (HadCM3BL-M2.2; Valdes et al., 2017). Two independent dynamic vegetation models were used to provide two sets of equivalent vegetation variables which yielded two different wetland predictions. As a first test, the method, using both vegetation models, satisfactorily reproduces modern day wetland fraction at a course grid resolution, similar to those used in paleoclimate simulations. We then applied the method to an early Eocene climate, testing its outputs against the locations of Eocene coal deposits. We predict global mean monthly wetland fraction area for the early Eocene of 8×106 to 10×106 km2 with a corresponding total annual methane flux of 656 to 909 Tg CH4 yr−1, depending on which of the two different dynamic global vegetation models are used to model wetland fraction and methane emission rates. Both values are significantly higher than estimates for the modern day of 4×106 km2 and around 190 Tg CH4 yr−1 (Poulter et al., 2017; Melton et al., 2013).

scholarly journals A Predictive Algorithm For Wetlands In Deep Time Paleoclimate Models

2018 ◽  
Author(s):  
David J. Wilton ◽  
Marcus Badger ◽  
Euripides P. Kantzas ◽  
Richard D. Pancost ◽  
Paul J. Valdes ◽  
...  
Keyword(s):  
Methane Emission ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Grid Cell ◽  
Methane Flux ◽  
Early Eocene ◽  
Emission Rates ◽  
Deep Time ◽  
Vegetation Models

Abstract. Methane is a powerful greenhouse gas produced in wetland environments via microbial action in anaerobic conditions. If the location and extent of wetlands are unknown, such as for the Earth many millions of years in the past, a model of wetland fraction is required in order to calculate methane emissions and thus help reduce uncertainty in the understanding of past warm greenhouse climates. Here we present an algorithm for predicting inundated wetland fraction for use in calculating wetland methane emission fluxes in deep time paleoclimate simulations. The algorithm determines, for each grid cell in a given paleoclimate simulation, the wetland fraction predicted by a nearest neighbours search of modern day data in a space described by a set of environmental, climate and vegetation variables. To explore this approach, we first test it for a modern day climate with variables obtained from observations and then for an Eocene climate with variables derived from a fully coupled global climate model (HadCM3BL-M2.2). Two independent dynamic vegetation models were used to provide two sets of equivalent vegetation variables which yielded two different wetland predictions. As a first test the method, using both vegetation models, satisfactorily reproduces modern data wetland fraction at a course grid resolution, similar to those used in paleoclimate simulations. We then applied the method to an early Eocene climate, testing its outputs against the locations of Eocene coal deposits. We predict global mean monthly wetland fraction area for the early Eocene of 8 to 10 × 106 km2 with corresponding total annual methane flux of 656 to 909 Tg, depending on which of two different dynamic global vegetation models are used to model wetland fraction and methane emission rates. Both values are significantly higher than estimates for the modern-day of 4 × 106 km2 and around 190 Tg (Poulter et. al. 2017, Melton et. al., 2013).

scholarly journals Values of methane emission from drainage ditches

2012 ◽  
Vol 3 (2) ◽  
pp. 1-10 ◽  
Author(s):  
A A Sirin ◽  
G G Suvorov ◽  
M V Chistotin ◽  
M V Glagolev
Keyword(s):  
Water Level ◽  
Methane Emission ◽  
Water Flow Rate ◽  
Methane Flux ◽  
Drainage Area ◽  
Moscow Oblast ◽  
Emission Rates ◽  
Summer Period ◽  
Extraction Area ◽  
Methane Fluxes

Methane fluxes were measured from ditches on peatlands drained for different purposes in two testing areas in European part of Russia. We used static chamber method and gas chromatography for CH 4 analysis. In Moscow Oblast CH 4 emissions were measured from ditches on milled peat extraction area and on agricultural drainage area (used for haying) during 2005-2011. Ditch spacing for both sites is 40 m, width on water level – 1.5-2 m. Averaged (median) methane flux for summer period was 28.5 and 12.5 mgС-CH 4∙m –2∙h –1, respectively, at these sites. Averaged (median) methane flux for summer period was 28.5 and 12.5 mgС-CH 4∙m –2∙h –1 for these sites consequently. In 2009-2011 methane fluxes were also measured from the ditch on forest drainage area, upstream and downstream the dam built for mire restoration. Simple average CH 4 emission rate was much higher at tail-bay point with flowing water as compared with back point upstream the dam with stagnant water – 14.4 and 2.4 mgС-CH 4∙m –2∙h –1, consequently. We assume water flow rate supports water degassing and increase of CH 4 emission from ditches. In Tver Oblast methane flux was measured in 2010 from ditches on forested bog and on forested fen, both drained for forestry with ditch spacing approx. 100 m, and ditch width on water level – 1-1.5 m. Flux observed at first nutrient-poor site was much lower – 0.31 mgС-CH 4∙m –2∙h –1, as compared with nutrient-rich one – 3.88 mgС-CH 4∙m –2∙h –1. Using methane emission rates from ditches and fractional area of ditches we calculate emission factors from drained peatlands. The results showed rather high values which need to be considered while assessing GHG emissions from drained peatlands.

scholarly journals Diurnal and Seasonal Patterns of Methane Emissions from a Dairy Operation in North China Plain

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Zhiling Gao ◽  
Huijun Yuan ◽  
Wenqi Ma ◽  
Jianguo Li ◽  
Xuejun Liu ◽  
...  
Keyword(s):  
Methane Emission ◽  
North China Plain ◽  
North China ◽  
Methane Emissions ◽  
Emission Rates ◽  
Inverse Dispersion ◽  
Four Seasons ◽  
Feeding Activities ◽  
Gross Energy ◽  
Dispersion Technique

In China, dairy cattle managed in collective feedlots contribute about 30% of the milk production and are believed to be an important contributor to national methane emissions. Methane emissions from a collective dairy feedlot in North China Plain (NCP) were measured during the winter, spring, summer, and fall seasons with open-path lasers in combination with an inverse dispersion technique. Methane emissions from the selected dairy feedlot were characterized by an apparent diurnal pattern with three peaks corresponding to the schedule of feeding activities. On a per capita basis, daily methane emission rates of these four seasons were 0.28, 0.32, 0.33, and 0.30 kg head−1 d−1, respectively. In summary, annual methane emission rate was 112.4 kg head−1 yr−1associated with methane emission intensity of 32.65 L CH4L−1of milk and potential methane conversion factor Ymof 6.66% of gross energy intake for mature dairy cows in North China Plain.

Methane emission rates from water infrastructures derived from mobile surveys along the final course of the Llobregat basin

2020 ◽  
Author(s):  
Roger Curcoll ◽  
Carme Estruch ◽  
Jordi Freixas ◽  
Josep-Anton Morgui
Keyword(s):  
Methane Emission ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Methane Emissions ◽  
Emission Rates ◽  
Processing Plants ◽  
Plume Modeling ◽  
Methane Potential

<p><span><span>The final course of the L</span></span><span><span>lobregat river (south-west of Barcelona, Spain) is surrounded by densely populated cities, </span></span><span><span>industrial areas and agricultural lands. Multiple water infrastructures where anaerobic processes may be expected are present in the basin: three wastewater treatment plants, a drinking water treatment plant, several irrigation channels and a desalination plant. Other likely methane emission infrastructures as waste processing plants or gas refilling stations are present, together with natural methane potential sources as wetlands.</span></span></p><p><span><span>Multiple mobile measurements were performed during 2019 along the final course of the Llobregat basin to study the variability of methane emissions throughout the year. The surveys were carried out in different days at different times with a car equipped with a flight-ready CO2/CH4/H2O cavity ring-down spectrometer.</span></span></p><p><span><span>Emissions of different infrastructures and its variability throughout the year has been determined using a statistical approach from the georeferenced data. Local winds and plume modeling has been used to better pinpoint the sources and </span></span><span><span>estimate</span></span><span><span> the emissions. Finally methane concentrations and emissions variability have been related with meteorological factors as temperature or pressure. These factors, together with human-related management of the water infrastructures, may drive the methane emissions significantly far from inventory estimations.</span></span></p>

scholarly journals Methane emissions from a sediment-deposited island in a Lancang-Mekong reservoir

2018 ◽  
Author(s):  
Wenqing Shi ◽  
Qiuwen Chen ◽  
Jianyun Zhang ◽  
Cheng Chen ◽  
Yuchen Chen ◽  
...  
Keyword(s):  
Methane Emission ◽  
Hyporheic Zone ◽  
Sediment Accumulation ◽  
Methane Flux ◽  
Methane Emissions ◽  
Mekong River ◽  
Hyporheic Exchange ◽  
Water Level Fluctuations ◽  
Hyporheic Flow ◽  
Methane Sink

Abstract. In dammed rivers, sediment accumulation creates potential methane emission hotspots, which have been extensively studied in forebays. However, methane emissions from sidebays remain poorly understood. We investigated methane emissions from a sediment-deposited island situated in the sidebay of the Manwan Reservoir, Lancang-Mekong River. High methane emissions (maximum 10.4 mg h−1 m−2) were observed at the island center, while a ring-like zone of low-to-negative methane emission was discovered around the island edge, whose flux varied between −0.2–1.6 mg h−1 m−2. The ring-like zone accounted for 89.1 % of the island area, of which 9.1 % was a methane sink zone. Microbial processes in the hyporheic zone, regulated by hydrological variations, were responsible for the low methane flux in this area. Under reservoir operation, frequent water level fluctuations enhanced hyporheic exchange and created redox gradients along the hyporheic flow path. Dissolved oxygen in hyporheic water decreased from 4.80 mg L−1 at the island bank edge to 0.43 mg L−1 at the center, which in turn decreased methanogen abundance for methane production and increased methanotroph abundance for methane oxidation at the ring-like zone. This study adds to our understanding of methane emissions from dammed rivers and helps to screen efficient strategies for future mitigation of the global warming effects of hydropower systems.

scholarly journals Microbial drivers of methane emissions from unrestored industrial salt ponds

2021 ◽  
Author(s):  
Jinglie Zhou ◽  
Susanna M. Theroux ◽  
Clifton P. Bueno de Mesquita ◽  
Wyatt H. Hartman ◽  
Ye Tian ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Methane Flux ◽  
Methane Emissions ◽  
Metagenomic Data ◽  
Rrna Gene ◽  
Salt Ponds ◽  
Salt Pond ◽  
Reference Wetlands ◽  
Reference Wetland ◽  
The Impact

AbstractWetlands are important carbon (C) sinks, yet many have been destroyed and converted to other uses over the past few centuries, including industrial salt making. A renewed focus on wetland ecosystem services (e.g., flood control, and habitat) has resulted in numerous restoration efforts whose effect on microbial communities is largely unexplored. We investigated the impact of restoration on microbial community composition, metabolic functional potential, and methane flux by analyzing sediment cores from two unrestored former industrial salt ponds, a restored former industrial salt pond, and a reference wetland. We observed elevated methane emissions from unrestored salt ponds compared to the restored and reference wetlands, which was positively correlated with salinity and sulfate across all samples. 16S rRNA gene amplicon and shotgun metagenomic data revealed that the restored salt pond harbored communities more phylogenetically and functionally similar to the reference wetland than to unrestored ponds. Archaeal methanogenesis genes were positively correlated with methane flux, as were genes encoding enzymes for bacterial methylphosphonate degradation, suggesting methane is generated both from bacterial methylphosphonate degradation and archaeal methanogenesis in these sites. These observations demonstrate that restoration effectively converted industrial salt pond microbial communities back to compositions more similar to reference wetlands and lowered salinities, sulfate concentrations, and methane emissions.

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