Differential effects of sulfide-induced transformation of biodegradable and conventional microplastics on sedimentary CO2 and CH4 emissions: Underlying microbiome-mediated mechanisms.

Unveiling the regulation of biochar and ferrihydrite on organic carbon stabilization, CH4 emission and microbial community in paddy soil.

Urban park metagenomics highlights sediments as a potential hotspot for CH4 and N2O emission across diverse habitats.

Effects of hummock-hollow microtopography on CO2 and CH4 emissions from sedge peatlands in the Changbai Mountains, Northeast China

Effects of encapsulated nitrate replacing urea on performance, rumen fermentation, and enteric methane emissions in grazing Nellore cattle from weaning to slaughter.

UAV-thermal driven machine learning framework for predicting methane emissions in tropical landfills

Electronic waste (e-waste) poses environmental issues and risks to health, but it holds polycarbonate, epoxy, and metal oxide, which have the potential for hydrogen production via the gasification process. This research involves the proper recycling of e-waste to an effective feedstock for hydrogen production via a plasma gasification process featuring a waste heat recovery system. During the plasma gasification process, the operating temperature is varied from 1500 to 3000°C with an interval of 500°C without a catalyst. The optimum plasma gasification temperature involves different concentrations of calcium oxide (CaO) catalyst for enriching the hydrogen yield. Effects of plasma gasification processing with a waste heat recovery system on energy consumption reduction, syngas yield, reactor stability, and carbon conversion efficiency are studied. The system featuring higher plasma gasification temperature (3000°C) found reduced energy consumption (48.9%) and enhanced hydrogen yield of 66.7mol/kg while reducing CH₄ and CO₂ emissions to 9.8mol/kg and 10.5mol/kg, respectively. The incorporation of a heat recovery system improved energy utilization efficiency to 71.5% and increased CCE (carbon conversion efficiency) from 69.8% to 91.6%. Additionally, CaO catalyst addition (15 wt%) further optimized gasification performance, leading to a hydrogen yield of 72.6mol/kg while reducing CH₄ and CO₂ emissions to 8.1mol/kg and 7.8mol/kg, respectively. These findings highlight plasma gasification as a viable and sustainable technology for hydrogen production from e-waste, offering significant environmental and energy efficiency benefits.

Intensifying global climate change has increased wildfire frequency. Wildfire-altered soil water-extractable organic matter (burned-WEOM) is hydrologically transported to unburned areas, profoundly affecting cross-ecosystem carbon-nitrogen cycling and greenhouse gas (GHG) emissions. Taking soils from unburned subtropical forests as the research object, this study combined anaerobic incubation with high-resolution mass spectrometry and metagenomic sequencing to elucidate the regulatory mechanisms of burned-WEOM on soil GHG emissions under anaerobic conditions. The results showed that burned-WEOM increased CO2 emissions by 17.0%, induced a 164.6% surge in N2O emissions, and simultaneously inhibited CH4 emissions by 52.9%. With unique properties of high unsaturation and strong electron exchange capacity, burned-WEOM not only reshapes soil organic matter composition but also drives differential GHG emissions by enhancing complete carbon fixation pathways and recalcitrant carbon decomposition, increasing the abundance of anaerobic methane oxidation (AMO) genes and methanotrophs, enriching denitrifying microorganisms (especially fungi), and boosting N2O-generating gene activity without altering the reduction pathway. Moreover, WEOM molecular characteristics drive differences in GHG emissions: CH4 is mainly fueled by reduced, unsaturated lipid-like compounds, N2O is associated with nitrogen-rich, complex aromatic compounds, and CO2 has a broader range of source substrates. This study provides insights that may improve mechanistic understanding of postfire GHG dynamics and inform process representations in climate models.

A multidisciplinary review of emission reductions and adoption potential of livestock manure acidification systems.

Urban forests are important carbon sinks; however, urban tree exchange of non-CO2 greenhouse gases (GHGs), particularly methane (CH4) and nitrous oxide (N2O), remains largely unexplored. Urban trees may channel CH4 and N2O from anaerobic compacted soils, resulting in foliar emission. We provide empirical evidence that urban street tree foliage emits CH4 and N2O and demonstrate that soil biochar can mitigate these emissions. Using in situ gas-exchange measurements on Ulmus americana "Valley Forge" and Celtis occidentalis in Toronto, Canada, we compared foliar and soil CH4 and N2O fluxes across biochar treatments (0, 20, 40 t ha-1) and seasons. Foliage of control trees emitted CH4 (0.03-0.13 nmol·m-2·s-1) and N2O (0.06-0.12 pmol·m-2·s-1). Biochar shifted foliar CH4 exchange from weak emission to net uptake and reduced N2O emissions by up to 70%; with similar patterns for soil fluxes. Structural equation modeling revealed strong coupling between soil and foliar fluxes, implicating xylem-mediated transport of dissolved gases. City-level scaling suggests that biochar amendment could convert Toronto's urban canopy from a minor CH4 source (∼30 t yr-1) to a net sink (∼60 t yr-1) while halving N2O emissions. These findings highlight an overlooked GHG pathway and identify biochar as a strategy for mitigating non-CO2 emissions and accelerating urban decarbonization.

The effect of a water-based delivery of an Ascophyllum nodosum extract on nitrogen balance, milk production and methane output in mid-late lactation dairy cows.

Inoculation effects on microbial and methane dynamics in daily filled dairy manure storage.

Superphosphate-driven low-pH regime reduces greenhouse gas emissions during manure composting.

Paphia undulata enhances sedimentary CH4 and N2O emissions via divergent microbial mechanisms.

Methane (CH4) is a potent greenhouse gas with a 100-year global warming potential approximately 27.9 times that of carbon dioxide, contributing to approximately 19% of historical global warming. Inland freshwater ecosystems are significant natural sources of CH4 emissions and constitute the greatest uncertainty in the global methane budget. This review systematically synthesizes recent advances in understanding the biogeochemical cycling processes and environmental drivers of CH4 in inland freshwater systems. Special emphasis is placed on the "methane paradox", which is the phenomenon of CH4 supersaturation in oxic waters, and highlights oxic methane production as a nonclassical pathway for CH4 production. Oxic methane production occurs via multiple enzymatic and nonenzymatic mechanisms under oxygen-rich conditions and is driven primarily by methyl- and hydrogen-coupled reactions. This process is synergistically regulated by nutrient status, light conditions, thermal stratification, and functional microbial communities. Furthermore, this review integrates key processes governing CH4 dynamics from production to emission, including diffusive flux, ebullition, and plant-mediated transport, as well as consumption by both aerobic and anaerobic methane oxidation. These findings underscore how environmental factors and hydrological dynamics collectively regulate microbial metabolic activity and substrate availability, thereby determining net CH4 emissions. Future research should prioritize multiscale observational efforts, integrate advanced technologies with mechanistic models, and quantify the contribution of oxic methane production and multifactor interactions to refine estimates of the global methane budget and support climate change mitigation strategies.

Enteric methane (CH4) emissions from ruminants are a major source of agricultural greenhouse gases and represent an energy loss to the host. Methyl-coenzyme M reductase (MCR) is the terminal enzyme in methanogenesis and represents a key target for CH4 mitigation. This study integrated computational screening, in vitro fermentation, and in vivo experiments to identify plant-derived compounds capable of reducing enteric CH4. Molecular docking of 3,900 phytochemicals identified proanthocyanidins (PAC) as top candidate, exhibiting strong predicted affinity to the MCR active site (-8.150kcal/mol). In vitro rumen fermentation assays showed that PAC supplementation reduced CH4 production by 22% while increasing dry matter degradability. In lactating dairy cows, dietary PAC supplementation (10 or 20g/kg dry matter) decreased daily CH4 emissions by ~ 8%, and improved ruminal nitrogen utilization without affecting milk yield or ruminal volatile fatty acid production. Amplicon sequencing and metagenomic analyses revealed PAC supplementation shifts in rumen microbial community, characterized by increased relative abundance of Bacteroidota taxa and a decreased relative abundance of methanogenesis-related genes. Functional genes associated with carbohydrate, lipid, and nitrogen turnover were more abundant, indicating potential improvements in nutrient utilization. Consistent with these changes, untargeted metabolomics likewise identified shifts in metabolite profiles that may associated with alternative routes for utilizing reducing equivalents. This study provides integrated computational, microbial, and physiological evidence that PAC supplementation can reduce enteric CH4 emissions in lactating dairy cows, inducing rumen microbial and functional shifts and improving nitrogen utilization. These findings support the potential of PAC as a natural approach to lowering CH4 emissions and advancing sustainable dairy production. Video Abstract.

Degradable and non-degradable microplastics regulate soil greenhouse gas emissions: Multi-factor insights and key monitoring factors from a Kolmogorov-Arnold Network ensemble model.

Lake Kasumigaura, the second-largest lake in Japan, is shallow, well-oxygenated, and eutrophic. Since shallow lakes are hotspots for methane（CH4）emissions, understanding CH4 oxidation - the process that reduces CH4 emissions - is essential. This study examines aerobic CH4 oxidation in Lake Kasumigaura to clarify seasonal fluctuations over six years and the factors that influence it. There was a seasonal dynamic in aerobic CH4 oxidation in Lake Kasumigaura, with the highest rates in autumn and the lowest in spring. The peak values for both the specific CH4 oxidation rate (0.0764 ± 0.04h-1)and the CH4 consumption rate (14.9 ± 13.3 nM CH4 h-1)occurred in autumn. Moderate activity was recorded in both summer and winter. Using quantitative PCR and Next-Generation Sequencing, it was found that, unlike in other freshwater lakes, Lake Kasumigaura's methanotrophic community is mainly composed of Methylocystis, a Type II methanotroph. Redundancy analysis revealed niche differentiation: Methylocystis (Type II) correlates strongly with TN and NO3-, while Type I methanotrophs are less abundant and more sensitive to dissolved CH4 and water temperature (W.T.). Variations in the dominant methanotrophs (revealed by pmoA gene analyses) in lake water, along with the complex relationships between environmental factors and these communities, highlight the unique biogeochemical properties of Lake Kasumigaura.

Interplay of quorum-sensing signals (homoserine lactone/penicillic acid) and nitrate in regulating microbial processes: As(III) immobilization, CH4 and N2O emission in constructed wetlands.

Relevance. The Tsimlyansk reservoir and other artificial reservoirs are considered by modern science as anthropogenic sources of entry of climatically active gases, including methane into the atmosphere. However, researchers differ in their estimates of CH4 emissions from reservoirs. The identification of patterns and main factors determining the spatial and seasonal variability of methane emissions, its concentrations in water and bottom sediments in the studied reservoir is the most important task of conducting research in the water area of the carbon landfill "Tsimlyanskoe reservoir". Methods. Comprehensive expeditionary studies have been conducted with sampling of water, sediments, and methane fluxes at the water-atmosphere boundary. The methane content was determined by the gas chromatographic method on a gas chromatograph with a flame ionization detector and an equilibrium vapor dispenser. The method of high-temperature catalytic oxidation on a carbon analyzer was used to quantify dissolved organic carbon. Vertical probing of the water column to determine the characteristics of the water is performed using a multiparametric probe. Results. Data on spatial and temporal variability of methane concentrations in water, bottom sediments, and its emission fluxes in the Tsimlyansk reservoir have been obtained. The interrelationships between some hydro/chemical parameters and methane concentrations are described. Quantitative estimates of CH4 emissions from the reservoir's water surface have been obtained.