Dynamics Of Methane Emissions Research Articles

Diversity and Distribution of Methane Functional Microorganisms in Sedimentary Columns of Hongfeng Reservoir in Different Seasons.

Freshwater ecosystem is a significant natural source of CH4 emission in the atmosphere. To fully understand the dynamics of methane emissions in reservoirs, it is essential to grasp the temporal and vertical distribution patterns, as well as the factors that influence the methanogenic bacterial communities within the sediments. This study investigates the methane dynamics, carbon isotope fractionation (δ13CH4), and abundance of functional microorganisms along the geochemical gradient in the in situ sedimentary column of Hongfeng Reservoir (China). Notably, the methane concentration in sediment in summer ranged in 15.39-127.22µmol/L, which is twice as high as wintertime concentrations in the surface layer near the sediment-water interface (0-10cm depth). Illumina sequencing of the sediments identified 11 genera affiliated with methanogenic archaea, with dominant genus Methanosaeta reaching a relative abundance of 34.95% in summer. The total carbon (TOC) content in sedimentary columns in different seasons is positively correlated with Methanosarcina (P < 0.05). In addition, seasonal discrepancies are observed in the sediment profiles for total nitrogen (TN), sulfate (SO42-), and ferrous iron (Fe2+) concentrations. The concentration of total nitrogen (TN) is higher in summer than in winter. In summer, sulfate accumulates in the middle layer of the sedimentary column, while in winter, the maximum concentration of sulfate in the surface layer reaches 0.65mmol/L. These geochemical gradients drive the biological transformation of nitrogen, sulfur, and iron, may also be linked to the consumption of methane. Thus, it is established that the temporal and spatial dynamics of methanogenic communities in sediments significantly influence the fluctuations in methane release fluxes within reservoirs, highlighting the necessity to account for seasonal biological variations when assessing greenhouse gas emissions from reservoirs.

Biochanin A feed supplementation alters dynamics of trace gas emissions from lamb urine-amended soil.

Sustainable growth in livestock production requires reductions in trace gas emissions on grazing lands. Urine excreta patches are hot spots for accelerated emissions of carbon and nitrogen. Ruminant dietary supplementation with the isoflavone biochanin A (BCA) has been shown to improve cattle weight gain. To determine if BCA supplementation affects urine N excretion and soil trace gas emissions, soil in microcosms was amended with urine from lambs fed 0, 0.45, or 0.90g BCA day-1. Soil gas emissions were measured over 60 days and analyzed with a linear mixed-effects model with repeated measures. On 2 days during the incubation, BCA addition across doses significantly reduced nitrous oxide emissions by 73% and methane by 98% compared to urine from non-dosed lambs. Cumulative ammonia volatilization was significantly reduced by 33% but cumulative nitrous oxide and methane emissions were not. Alterations in trace gas emissions occurred despite no change in urine N content with BCA feed supplementation. A separate laboratory incubation using urine from a non-supplemented lamb that was exogenously spiked with varying BCA concentrations supported these results: BCA significantly altered ammonia and methane emission dynamics and reduced cumulative nitrous oxide emissions by up to 41%. BCA did not change soil microbial community structure, suggesting alterations to other processes, such as soil enzyme activity, were affecting soil trace gas emissions. Overall, lamb BCA supplementation did not affect urine N but reduced ammonia volatilization, which may contribute to greater sustainability in livestock production systems.

Dynamics of methane emissions from northwestern Gulf of Mexico subtropical seagrass meadows

While seagrass meadows are perceived to be pertinent blue carbon reservoirs, they also potentially release methane (CH4) into the atmosphere. Seasonal and diurnal variations in CH4 emissions from a subtropical hypersaline lagoon dominated by Halodule wrightii in southern Texas, USA, on the northwest coast of the Gulf of Mexico were investigated. Dissolved CH4 concentrations decreased in the daytime and increased overnight during the diel observation period, which could be explained by photosynthesis and respiration of seagrasses. Photosynthetic oxygen was found to significantly reduce CH4 emissions from seagrass sediment. Diffusive transport contributed slightly to the release of CH4 from the sediment to the water column, while plant mediation might be the primary mechanism. The diffusive CH4 flux at the sea-air interface was 12.3–816.2 µmol/m2 d, over the range of the sea-air fluxes previously reported from other seagrass meadows. This was related to relatively higher dissolved CH4 concentrations (11.6–258.2 nmol/L) in a mostly closed lagoon with restricted water exchange. This study emphasizes seagrass meadows in the subtropical hypersaline lagoon as a source of atmospheric CH4, providing insights into the interactions between seagrass ecosystems and methane dynamics, with potential implications for seagrass meadow management and conservation efforts.

Shallow and deep groundwater moderate methane dynamics in a high Arctic glacial catchment

Glacial groundwater can mobilize deep-seated methane from beneath glaciers and permafrost in the Arctic, leading to atmospheric emissions of this greenhouse gas. We present a temporal, hydro-chemical dataset of methane-rich groundwater collected during two melt seasons from a high Arctic glacial forefield to explore the seasonal dynamics of methane emissions. We use methane and ion concentrations and the isotopic composition of water and methane to investigate the sources of groundwater and the origin of the methane that the groundwater transports to the surface. Our results suggest two sources of groundwater, one shallow and one deep, which mix, and moderate methane dynamics. During summer, deep methane-rich groundwater is diluted by shallow oxygenated groundwater, leading to some microbial methane oxidation prior to its emergence at the surface. Characterization of the microbial compositions in the groundwater shows that microbial activity is an important seasonal methane sink along this flow-path. In the groundwater pool studied, we found that potential methane emissions were reduced by an average of 29% (±14%) throughout the summer due to microbial oxidation. During winter, deep groundwater remains active while many shallow systems shut down due to freezing, reducing subsurface methane oxidation, and potentially permitting larger methane emissions. Our results suggest that ratios of the different groundwater sources will change in the future as aquifer capacities and recharge volumes increase in a warming climate.

Impact of Water Management on Methane Emission Dynamics in Sri Lankan Paddy Ecosystems

Paddy ecosystems constitute a dominant source of greenhouse gases, particularly of methane (CH4), due to the continuous flooding (CF) practiced under conventional paddy cultivation. A new management method, namely alternative wetting and draining (AWD) (i.e., flooding whenever surface water levels decline to 15 cm below the soil surface), is an emerging practice developed to mitigate CH4 emissions while providing an optimal solution for freshwater scarcity. Despite extensive paddy cultivation in Sri Lanka, no systematic research study has been conducted to investigate CH4 emissions under different water management practices. Thus, field experiments were conducted in Sri Lanka to investigate the feedback of controlled water management on seasonal and diel variation of CH4 emission, water consumption, and crop productivity. Adopting the same rice variety, two water management methods, continuous flooding (CF) and alternative wetting and draining (AWD), were compared with plants (W/P) and without plants (N/P) present. The emission of CH4 was measured using the static closed chamber method. The results show a 32% reduction in cumulative CH4 emission, on average, under AWD when compared to CF. The yield under the AWD was slightly higher than that of CF. Although it was not statistically significant (p &gt; 0.05) there was not any reduction in yield in AWD than in CF. The total water saving under AWD ranged between 27–35% when compared to CF. Thus, the results support (without considering the effect of nitrous oxide) AWD as a promising method for mitigating CH4 emissions while preserving freshwater and maintaining grain yield in paddy systems.

Salinity causes differences in stratigraphic methane sources and sinks

Methane metabolism, driven by methanogenic and methanotrophic microorganisms, plays a pivotal role in the carbon cycle. As seawater intrusion and soil salinization rise due to global environmental shifts, understanding how salinity affects methane emissions, especially in deep strata, becomes imperative. Yet, insights into stratigraphic methane release under varying salinity conditions remain sparse. Here we investigate the effects of salinity on methane metabolism across terrestrial and coastal strata (15–40 m depth) through in situ and microcosm simulation studies. Coastal strata, exhibiting a salinity level five times greater than terrestrial strata, manifested a 12.05% decrease in total methane production, but a staggering 687.34% surge in methane oxidation, culminating in 146.31% diminished methane emissions. Salinity emerged as a significant factor shaping the methane-metabolizing microbial community's dynamics, impacting the methanogenic archaeal, methanotrophic archaeal, and methanotrophic bacterial communities by 16.53%, 27.25%, and 22.94%, respectively. Furthermore, microbial interactions influenced strata system methane metabolism. Metabolic pathway analyses suggested Atribacteria JS1's potential role in organic matter decomposition, facilitating methane production via Methanofastidiosales. This study thus offers a comprehensive lens to comprehend stratigraphic methane emission dynamics and the overarching factors modulating them.

Substantiation of Drilling Parameters for Undermined Drainage Boreholes for Increasing Methane Production from Unconventional Coal-Gas Collectors

Decarbonization of the mining industry on the basis of closing the energy generation, on the basis of cogeneration of coal mine methane, and on the internal consumption of the mine is a promising direction in ensuring sustainable development. Known problems of deep underground mining do not allow for realizing the potential of man-made gas reservoirs due to the deterioration of the conditions of development of reserves of georesources. The aim of the work was to improve recommendations for the substantiation of drilling parameters for undermined drainage boreholes for increasing methane production from unconventional coal-gas collectors. The authors’ approach innovation lies in the possibility of using the established patterns of better natural stability of undermined boreholes to optimize them as spatial orientation parameters in an existing drilling passport for the improvement of methane extraction productivity. For this purpose, smoothing (LOESS) of the experimental data of two similar types of wells was used; then deterministic interpolation methods in combination with a three-dimensional representation of the response function in “gnuplot” were used. As a result, it was found that the increase in the inclination angle from 40° to 60° leads to a significant transformation of the model of the studied process, accompanied by a decline in the dynamics of methane emission and a decrease in the distance of the productive work zone of this type of well from 13 to 5 m before the roof landing, which then is replaced by a sharp increase in the productive work zone up to 35 m ahead of the longwall face. This allows under specific conditions for recommending increasing the productivity of methane capex from technogenic disturbed coal-gas reservoir replacement of wells with a smaller angle of rise to the transition to a more frequent grid of clusters from wells #4.

Spectrometric imaging of sub-hourly methane emission dynamics from coal mine ventilation

Anthropogenic methane (CH4) emissions contribute significantly to the current radiative forcing driving climate change. Localized CH4 sources such as occurring in the fossil fuel industry contribute a substantial share to the anthropogenic emission total. The temporal dynamics of such emissions is largely unresolved and unaccounted for when using atmospheric measurements by satellites, aircraft, and ground-based instruments to monitor emission rates and verify reported numbers. Here, we demonstrate the usage of a ground-based imaging spectrometer for quantifying the CH4 emission dynamics of a ventilation facility of a coal mine in the Upper Silesian Coal Basin, Poland. To this end, we deployed the imaging spectrometer at roughly 1 km distance from the facility and collected plume images of CH4 column enhancements during the sunlit hours of four consecutive days in June 2022. Together with wind information from a co-deployed wind-lidar, we inferred CH4 emission rates with roughly 1 min resolution. Daily average emission rates ranged between 1.39 ± 0.19 and 4.44 ± 0.76 tCH4 h−1, 10 min averages ranged between (min) 0.82 and (max) 5.83 tCH4 h−1, and puff-like events caused large variability on time scales below 15 min. Thus, to monitor CH4 emissions from such sources, it requires measurement techniques such as the imaging spectrometer evaluated here that can capture emission dynamics on short time scales.

Seasonality of methane and carbon dioxide emissions in tropical seagrass and unvegetated ecosystems

Seagrass ecosystems are important carbon dioxide sinks that can sequester carbon for centuries as organic matter in sediment. They are also a major source of methane, a potent greenhouse gas, which limits their carbon sink capacity. However, data are lacking on their methane emission dynamics. Here, we conduct a one-year survey of carbon dioxide and methane concentrations and air-sea fluxes in Red Sea seagrass, mudflat, and coral backreef ecosystems. All ecosystems were sources of methane and carbon dioxide. Methane concentrations were lowest in the reef lagoon. We suggest that lagoons may be a globally important source of greenhouse gases. Methane concentrations were lower in seagrass than mudflat ecosystems at temperatures below 29.2 °C. Seagrass had the highest annual methane air-sea fluxes but the lowest global warming potential in carbon dioxide equivalent due to a decrease in its flux. Hence, seagrasses can help climate change mitigation compared to bare sediments.

ОБОСНОВАНИЕ ТЕОРЕТИЧЕСКОЙ МОДЕЛИ МЕТАНООПАСНОЙ ШАХТЫ ДЛЯ РЕШЕНИЯ ПРОГНОЗНЫХ ЗАДАЧ НА ПРИМЕРЕ ШАХТ КУЗБАССА

Statistical analysis of accidents in coalmines by the aerogasdynamic factor shows that the effectiveness of existing methods for predicting the risk of explosions of methane-air mixture in the mine workings of coalmines is unsatisfactory. So it is necessary to improve the physical model and mathematical description of the threat of explosive gas situations in the mine workings of a model mine. In general, a systematic approach to reducing the risk and localizing the consequences of methane explosions in coalmines comes down to solving the following problems. Substantiation of algorithms and development of a software package for modeling air distribution in coalmine workings under normal and emergency operation modes. Improving the technology for examining mine ventilation systems and preparing initial data for models. Substantiation of algorithms and development of a software package for modeling coal-degassing systems. Substantiation of models of methane emission dynamics from various sources. Substantiation of models of dynamics of methane concentration in mine workings of coal mines.

Impact of Water Table on Methane Emission Dynamics in Terrestrial Wetlands and Implications on Strategies for Wetland Management and Restoration

Impact of Water Table on Methane Emission Dynamics in Terrestrial Wetlands and Implications on Strategies for Wetland Management and Restoration

Organic farms are the fundamental basis for the sustainable foreign economic activities of agrarians in Ukraine

Abstract The article emphasizes the importance of organic production development in the agricultural sector of the Ukrainian economy and substantiates that one of the important priorities of agribusiness is organic production, which is mainly export-oriented, and therefore is the fundamental basis for the sustainability of the foreign economic activity of its farmers. An increase in organic production, in particular cattle products, is accompanied by additional methane emissions (but lower than those from nonorganic production), while Ukraine, having joined the Global Methane Pledge initiative to reduce methane emissions, has committed to taking measures to reduce its methane footprint and consequently the decision to invest and/or provide government support for development programs should be based on historical analysis using a decoupling approach. The trends of changes in the average annual livestock population, the livestock production volume and dynamics of methane emissions have been studied for the period of 1990-2019. A decoupling analysis has been carried out of the gap between trends of the economic growth rates of the livestock industry and the rates of anthropogenic pressure on the environment. The study demonstrated that the decoupling effect in cattle breeding has changed abruptly from strongly negative to weak decoupling. The dynamics of the export volume of dairy and meat products were analysed for the agribusiness of Ukraine during 2004-2021 and a forecast of changes in production volumes, as well as a forecast for the export volume of milk and beef were made for the period up to 2030.

Predicting the dynamics of enteric methane emissions based on intake kinetic patterns in dairy cows fed diets containing either wheat or corn

The production of methane by the rumen microbiota is a complex biological process. When tackling the modelling of methane production, the modeller decides what complexity is needed to answer the scientific question for which the model is intended. Such a choice results in a diversity of possible models spanning both empirical and mechanistic approaches. Within the framework of precision livestock farming, simple dynamic models offer great advantages for integrating online data (e.g., feed intake) to predict individual methane emissions from cattle. Accordingly, we previously developed, with satisfactory results, a simple dynamic model that uses DM intake kinetics as a single predictor of methane emissions from finishing beef steers. The objective of the present work was to assess the capability of the previously developed model to predict the dynamic pattern of methane production from dairy cows fed a diet containing either wheat grain or corn grain. We showed that the simple dynamic model in its original form enables a description of the dynamics of individual methane emissions from dairy cows with an average determination coefficient (r2) of 0.65 and an average concordance correlation coefficient of 0.81 and RMSE of 16% and 26% for the corn-based and wheat-based diets, respectively. Additionally, we performed a principal component analysis associating the parameters of the methane model with variables characterising the feeding behaviour of the cows. The results showed the effect of the diet type on the feeding behaviour of the animals. This impact was propagated on the dynamics of methane emissions. Interestingly, our model enabled us to determine that the differences in patterns of methane emissions between the diets result simply from the dependency of the methane yield and rate constant of methane eructation on the grain type.

Methane emission dynamics from a Danish landfill: The effect of changes in barometric pressure.

This study investigates temporal variability on landfill methane (CH4) emissions from an old abandoned Danish landfill, caused by the rate of changes in barometric pressure. Two different emission quantification techniques, namely the dynamic tracer dispersion method (TDM) and the eddy covariance method (EC), were applied simultaneously and their results compared. The results showed a large spatial and temporal CH4 emission variation ranging from 0 to 100kgh-1 and 0 to 12μmol m-2 s-1, respectively. Landfill CH4 emissions dynamics were influenced by two environmental factors: the rate of change in barometric pressure (a strong negative correlation) and wind speed (a weak positive correlation). The relationship between CH4 emissions and the rate of change in barometric pressure was more complicated than a linear one, thereby making it difficult to estimate accurately annual CH4 emissions from a landfill based on discrete measurements. Furthermore, the results did not show any clear relationship between CH4 emissions and ambient temperature. Large seasonal variations were identified by the two methods, whereas no diurnal variability was observed throughout the investigated period. CH4 fluxes measured with the EC method were strongly correlated with emissions from the TDM method, even though no direct relationship could be established, due to the different sampling ranges of the two methods and the spatial heterogeneity of CH4 emissions.

Methane emission dynamics in mining in zones of geological faults

Methane emission dynamics in mining in zones of geological faults

Do methane emissions converge? Evidence from global panel data on production- and consumption-based emissions

Methane emissions are the second most important contributor to global warming. Knowledge about the dynamics of methane emissions facilitates the formulation of climate policies and the understanding of their consequences. We investigate whether methane emissions released from production and embodied in consumption converge within and across regions. Our estimates rely on global panel data on methane per capita and methane intensities over 1997–2014. We find that emissions converge within countries. The short half-lives show that the emissions of countries are close to their steady states. There is no evidence for international convergence of aggregate emissions. Yet, convergence of emissions across regions occurs in a number of economic sectors. Our results highlight the difficulties to achieve methane abatement in the medium run. The formulation of climate policies should take into account the sectoral specificity of the dynamics of methane emissions.

Methane emission dynamics among CO2-absorbing and thermokarst lakes of a great Arctic delta

Methane emission dynamics among CO2-absorbing and thermokarst lakes of a great Arctic delta

The effect of methane emission on air distribution in potash mine production units

Introduction. It has been found that due to light gas (including methane) emission in rooms under development, there develops an additional natural draught between the mine workings. The calculation has shown that methane emission from the rock mass conditions the low value of the additional natural draught. However, even minor additional natural draught interacting with a thermal drop of pressure caused by temperature rise in the conveyor shaft changes the direction of the delivery air stream. While in up the dip blocks and panels the resultant natural draught promotes ventilation, in the down the dip production units it prevents air circulation in the required direction. Research methods. The methods and results of calculating the value and direction of the natural draught for real panels of potash mines at the Upper Kama potash deposit under various conditions have been presented together with the simulation observations of methane distribution in the room with a point source of emission. Results. Model analysis has shown that even under the low amount of gas emission out of the point source in the blind room (of a hole drilled in the roof), the concentration of gas in the gas-air mixture entering the belt heading reaches 2%. Conclusions. To ensure the safety of mining and reduce the risk of emergency when calculating the volume of air required to ventilate the production units, the dynamics of methane emission out of the rock mass should be taken into account as well as its further distribution across the mine workings.

Influence of elevated carbon dioxide concentrations on methane emission and its associated soil microflora in 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.

An availibility of arctic lakes organic sediments to microbial degradation: a laboratory incubation experiment

The water ecosystems of the Arctic region are most vulnerable to modern climatic changes since the global biogeochemical processes mostly occur on the territories of the permafrost zone. Aquatic ecosystems show a high degree of sensitivity to climatic changes; both in these and in other ecosystems, the biogeochemical processes are intense. These water bodies are located in the permafrost zone, which is vulnerable to temperature increases. The paper gives new insights into the fundamental research question of how fast the organic matter of thawing permafrost can be converted to greenhouse gases emitted into the atmosphere (CO2, CH4). We aimed to assess the microbial response and the associated release of CO2 and CH4 from the Arctic lakes in response to temperature increase. We investigated lakes located in the Lena River delta in the Samoylov Island, Russia, at 72° 22′ N, 126° 28′ E. Bottom sediments from three thermokarst and three oxbow lakes were anaerobically incubated in the laboratory at two temperature regimes (at 4 °C and at 25 °C). All the oxbow lakes have shown similar dynamics of methane emission both at low temperatures (4 °C) and at high temperatures (25 °C). The shift of carbon isotopic composition in methane has indicated that methane is emitted in all the oxbow lakes with a similar composition of microbial communities. In the thermokarst lakes, the emission of methane in the sediments proceeded differently at low and at high temperatures. These results have indicated a dissimilar composition of methanogenic / methanotrophic populations in the thermokarst and oxbow lakes. In both cases, the temperature increase caused a growth in methane emission from the sediments of the Arctic lakes. The thermokarst lakes will make a greater contribution to methane emission than the oxbow lakes. Thus, it is believed that the emission of methane from the thermokarst lakes will rise from 6 to 46 times due to ambient temperature increase. Methane emission from the oxbow lakes will grow from 1.8 to 7.6 times. Our results suggest that with the global warming both thermokarst and oxbow lakes could become a great source of methane emission into the atmosphere.