Continental-scale estimations of terrestrial methane (CH4) and nitrous oxide (N2O) fluxes over a long time period are crucial to accurately assess the global balance of greenhouse gases and enhance our understanding and prediction of global climate change and terrestrial ecosystem feedbacks. Using a process-based global biogeochemical model, the Dynamic Land Ecosystem Model (DLEM), we quantifie...

Previous shotgun metagenomic analyses of ruminal digesta identified some microbial information that might be useful as biomarkers to select cattle that emit less methane (CH4), which is a potent greenhouse gas. It is known that methane production (g/kgDMI) and to an extent the microbial community is heritable and therefore biomarkers can offer a method of selecting cattle for low methane emitti...

To assess the role of floodwater in controlling the exchanges of CO2 and CH4 from soil, floodwater and the canopy in intermittently flooded rice paddies, an intensive field campaign (IREX96) was conducted in Japan during August 1996. Eddy covariance was employed to measure fluxes of heat, water vapor and CO2. The flux-gradient method was used to determine CH4 fluxes from measured profiles of CH...

Freshwaters are important sources of the greenhouse gases methane (CH4) and carbon dioxide (CO2) to the atmosphere. Knowledge about temporal variability in these fluxes is very limited, yet critical for proper study design and evaluating flux data. Further, to understand the reasons for the variability and allow predictive modeling, the temporal variability has to be related to relevant environ...

Modelling of wetland CH4 fluxes using wetland soil emission models is used to determine the size of this natural source of CH4 emission on local to global scale. Most process models of CH4 formation and soil-atmosphere CH4 transport processes operate on a plot scale. For large scale emission modelling (regional to global scale) upscaling of this type of model requires thorough analysis of the s...

Understanding the thermal and mechanical properties of CH4 and CO2 hydrates is essential for the replacement of CH4 with CO2 in natural hydrate deposits as well as for CO2 sequestration and storage. In this work, we present isothermal compressibility, isobaric thermal expansion coefficient and specific heat capacity of fully occupied single-crystal sI-CH4 hydrates, CO2 hydrates and hydrates of ...

The thermal rate coefficients and kinetic isotope effects have been calculated using ring polymer molecular dynamics (RPMD) for the prototypical reactions between methane and several hydrogen isotopes (H, D, and Mu). The excellent agreement with the theoretical rate coefficients of the H + CH4 reaction obtained previously from a multi-configuration time-dependent Hartree calculation on the same...

The objective of this review was to examine the application and relative efficiency of the proprietary hand-held Laser Methane Detector (LMD) in livestock production, with a focus on opportunities and challenges in different production systems. The LMD is based on IR absorption spectroscopy, uses a semiconductor laser as a collimated excitation source and uses the second harmonic detection of w...

OBJECTIVE Two experiments were conducted to determine the effects of forage-to-concentrate (F:C) ratio on the nutrient digestibility and enteric methane (CH4) emission in growing goats and Sika deer. METHODS Three male growing goats (body weight [BW] = 19.0±0.7 kg) and three male growing deer (BW = 19.3±1.2 kg) were respectively allotted to a 3×3 Latin square design with an adaptation period ...

[1] This study presents a new hypothesis to explain the observed variation of CH4 and dC-CH4 over the last millennium. It was originally proposed that the observed minimum of dC-CH4 prior to the start of industrialization is caused by a large shift in biomass burning emissions between 1400 and 1700 A.D. According to our new hypothesis, however, the dC-CH4 minimum is the first sign of the global...