Hydrogen (H2) is an essential substrate for methanogens to produce methane (CH4), and also influences pathways of volatile fatty acids (VFA) production in the rumen. Dissolved H2 (H2 (aq)) is the form of H2 available to microbes, and dissolved CH4 (CH4 (aq)) is important for indicating methanogens activity. Rumen H2 (aq) concentration has been estimated by assuming equilibrium with headspace ga...

Quantifying landscape-scale methane (CH4 ) fluxes from boreal and arctic regions, and determining how they are controlled, is critical for predicting the magnitude of any CH4 emission feedback to climate change. Furthermore, there remains uncertainty regarding the relative importance of small areas of strong methanogenic activity, vs. larger areas with net CH4 uptake, in controlling landscape-l...

Polar ice-core records suggest that an arctic or boreal source was responsible for more than 30% of the large increase in global atmospheric methane (CH4) concentration during deglacial climate warming; however, specific sources of that CH4 are still debated. Here we present an estimate of past CH4 flux during deglaciation from bubbling from thermokarst (thaw) lakes. Based on high rates of CH4 ...

Microbial cultures used for methane oxidation experiments were prepared by enriching under a 20 % CH4 atmosphere either leachate extracts from two different landfill sites or a digested sewage sludge. No microbes were axenically isolated, therefore the cultures were mixtures of CH4 oxidising and other aerobic microorganisms. CH4 oxidation experiments were carried out with a batch reactor, whose...

This manuscript presents valuable data on CH4 fluxes from the understudied permafrost region of NE Europe. CH4 fluxes were measured on the plot scale by closed chambers and on the landscape scale by the eddy covariance approach. The combination of these two approaches is a particular strength of this study. Furthermore, the authors present interesting data on stable carbon signatures of pore wa...

We use historical and new atmospheric trace gas observationsto refine the estimated source of methane (CH4) emitted into California’sSouth Coast Air Basin (the larger Los Angeles metropolitan region).Referenced to the California Air Resources Board (CARB) CO emissionsinventory, total CH4 emissions are 0.44 ± 0.15 Tg each year. To investigatethe possible contribution of fossi...

Optical emission spectra ~OES! from CH4/N2 rf plasmas, which are used for the deposition of nitrogen-containing hydrogenated amorphous carbon ~a-C:H:N! thin films, have been characterized. Previously unidentified spectral lines have been assigned to atomic N. Further identified species include CH, H, H2, N2, N2 1 , N, and CN. Variations between spectra from the pure CH4 or N2 plasmas and the mi...

abstract in this work, the dry reforming of methane was studied using a corona and glow discharge plasma microreactors. a chemical kinetic model was developed to understand the reaction better. the modelization allowed prediction of the reactants conversion according to the energy transfer to the gas (p×τ). the β value is trait of the energy cost, whatever this value was leeser indicated better...

We describe an assimilation system for atmospheric methane (CH4), CarbonTracker-CH4, and demonstrate the diagnostic value of global or zonally averaged CH4 abundances for evaluating the results. We show that CarbonTracker-CH4 is able to simulate the observed zonal average mole fractions and capture inter-annual variability in emissions quite well at high northern latitudes (53–90 N). In contras...

Atmospheric methane (CH4) varied with climate during the Quaternary, rising from a concentration of 375 p.p.b.v. during the last glacial maximum (LGM) 21,000 years ago, to 680 p.p.b.v. at the beginning of the industrial revolution. However, the causes of this increase remain unclear; proposed hypotheses rely on fluctuations in either the magnitude of CH4 sources or CH4 atmospheric lifetime, or ...