Isotopic tracer and kinetic measurements were used to determine the identity and reversibility of elementary steps required for CH4–CO2 , CH4–H2O and CH4 decomposition reactions on supported Ir clusters. The results led to a simple and rigorous mechanism that includes steps required for these reactions as well as water–gas shift reactions. All three CH4 reactions gave similar forward rates, rat...

[1] This study examined daily, seasonal, and interannual variations in CH4 emissions at a temperate peatland over a 5-year period. We measured net ecosystem CO2 exchange (NEE), CH4 flux, water table depth, peat temperature, and meteorological parameters weekly from the summers (1 May to 31 August) of 2000 through 2004 at Sallie’s Fen in southeastern New Hampshire, United States. Significant int...

[1] New measurements of the carbon and hydrogen isotopic ratios of methane (dC of CH4 and dD of CH4) over the last millennium are presented from the WAIS Divide, Antarctica, ice core (WDC05A), showing significant changes that likely were the result of human influences prior to the industrial revolution (at least as early as the 16th century of the common era (CE)). The dC of CH4 data corroborat...

[1] We conducted measurements of methane (CH4) emission and ecosystem respiration on >200 points across the Arctic coastal tundra near Barrow, Alaska, United States, in July 2007 and August 2008. This site contains broad diversity in tundra microtopography, including polygonal tundra, thaw lakes, and drained lake basins. In 2007, we surveyed CH4 emissions across this landscape, and found that s...

Wetlands are the largest natural source of methane (CH4) emissions to the atmosphere, which vary along salinity and productivity gradients. Global change has the potential to reshape these gradients and therefore alter future contributions of wetlands to the global CH4 budget. Our study examined CH4 production along a natural salinity gradient in fully inundated coastal Alaska wetlands. In the ...

Sources and sinks of methane (CH4 ) are critical for understanding global biogeochemical cycles and their role in climate change. A growing number of studies have reported that CH4 concentrations in cave ecosystems are depleted, leading to the notion that these subterranean environments may act as sinks for atmospheric CH4 . Recently, it was hypothesized that this CH4 depletion may be caused by...

We investigated soil CH4 fluxes from six forests along an urban-to-rural gradient in Guangzhou City metropolitan area, South China. The most significant CH4 consumption was found in the rural site, followed by suburban, and then urban forest sites. The rates of CH4 uptake were significantly higher (by 38% and 44%, respectively for mixed forest and broadleaf forest) in the rural than in the urba...

The global budget of atmospheric CH4 , which is on the order of 500-600 Tg CH4 per year, is mainly the result of environmental microbial processes, such as archaeal methanogenesis in wetlands, rice fields, ruminant and termite digestive systems and of microbial methane oxidation under anoxic and oxic conditions. This review highlights recent progress in the research of anaerobic CH4 oxidation, ...

Co-processing of formic acid or carbon dioxide with CH4 (FA/CH4 = 0.01-0.03 and CO2/CH4 = 0.01-0.03) on Mo/H-ZSM-5 catalysts at 950 K with the prospect of kinetically coupling dehydrogenation and deoxygenation cycles results instead in a two-zone, staged bed reactor configuration consisting of upstream oxygenate/CH4 reforming and downstream CH4 dehydroaromatization. The addition of an oxygenate...

The effect of draining crop fields during the wheat season on the soil CH4 andN2O emissions during the rice season in this article. There were four treatments:traditional cultivation during the wheat season + cultivation without fertilizationduring the rice season (CK1 field), traditional cultivation during the wheat season +traditional cultivation during the rice season (CK2 field), draining t...