Atmospheric Methane: Trends and Impacts

Wuebbles, Donald J.; Hayhoe, Katharine

doi:10.1007/978-94-015-9343-4_1

Cited by 15 publications

(10 citation statements)

References 164 publications

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“…It is estimated that methane is released into the atmosphere worldwide at a rate of about 503-610 Tg yr −1 [5]. Although hydrocarbon seeps release about 8-65 Tg yr −1 of methane into the ocean [6], only 4-15 Tg yr −1 of methane is released into the atmosphere, accounting for about 1%-2% of the global atmospheric methane flux [7][8][9][10][11][12]. These values reveal that methane undergoes a complicated set of processes (involving both anaerobic and aerobic oxidation) in the ocean, with more than 85% of methane being consumed before reaching to the sea surface [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

The Distribution of Dissolved Methane and Its Air-Sea Flux in the Plume of a Seep Field, Lingtou Promontory, South China Sea

Dong

Chen

2019

Geofluids

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Methane (CH4), the most abundant hydrocarbon gas in the atmosphere, plays an important role in global climate change. Quantifying the dissolved methane and its air-sea flux from hydrocarbon seeps is therefore of great importance. Large quantities of natural gas are emitted from the seafloor to the coastal ocean near the Lingtou Promontory, South China Sea. We quantified concentrations of methane in surface and bottom waters at 48 stations in a 56 km2 study area. High spatial variability in dissolved methane concentrations was observed in the surface mixed layer (0.5 m water depth) and bottom water (water-sediment interface), with values ranging from 2.90 nmol L−1 to 13570.02 nmol L−1 and from 4.98 nmol L−1 to 31740.02 nmol L−1, respectively. The significant difference between concentrations of dissolved methane in surface and bottom waters suggests that most of the methane emitted from the seafloor is dissolved in the water column. The dissolution of methane in seawater may result in local oxygen depletion that may lead to ecological effects. The δ13C values of dissolved methane ranging from −59.76‰ to −48.59‰ indicate a mixture of biogenic and thermogenic gas sources. The average air-sea methane flux of Yinggehai Basin was 672.57 μmol m−2 d−1, which cannot be ignored in environment assessment. Coastal regions, especially with hydrocarbon seeps in shallow waters of the continental margin, may therefore be an important source of methane to the atmosphere.

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Section: Introductionmentioning

confidence: 99%

The Distribution of Dissolved Methane and Its Air-Sea Flux in the Plume of a Seep Field, Lingtou Promontory, South China Sea

Dong

Chen

2019

Geofluids

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“…The monthly mean CH 4 volume mixing ratio (VMR) are presented in figure 4, shows a graph of monthly-long series for mean CH 4 4 concentration could be related to the magnitude of CH 4 sources in large cities which affected by many factors such as; human activities and population, energy demands and agriculture practices (expansion of rice field), land use and land cover, temperature, precipitation [26]. As well as, the reduction in (OH) radicals this is the main removal for many species, beside CH 4 , such as CO, CO 2 and NO 2 .…”

Section: Monthly Long-term Ch 4 Trend Analysismentioning

confidence: 99%

Space-borne observation of methane from atmospheric infrared sounder: data analysis and distribution over Iraq

Abed

AL-Salihi²,

Rajab³

2017

jaar

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Methane (CH 4 ) Volume Mixing Ratio (VMR) at pressure level 925hPa data extracted from Atmospheric Infrared Sounder (AIRS) with spatial resolution of 1°× 1° covering whole of Iraq and surrounding regions (28.5°-38.5°N, 37.5°-49.5°E) have been examined for the period from January 2003 to December 2013. The results show a considerable increasing of CH 4 with maximum values at north and north eastern regions during autumn and the early winter, whereas the minimum values appeared at the pristine desert environment at the west and the south-west region during spring months. For more accuracy validation the trend analysis was applied on the retrieved AIRS data at three different stations are Mosul, Baghdad and Basrah. The mean and standard deviation in Mosul, Baghdad and Basrah was (1.8657 ± 0.0198, 1.8536 ± 0.0196, 1.8448 ± 0.0212) ppmv respectively for monthly long term trend analysis. Monthly trend analyses have positive trends (0.0040, 0.0039 and 0.0042) ppmv.y -1 for Mosul, Baghdad and Basrah Consecutively. These results indicate that Satellite observations efficiently present the temporal and spatial variations of the CH 4 for the considered study Area.

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“…Methane, the principal component of natural gas, is an important source of clean renewable energy, with the highest heat production per mass unit (55.7 kJ g -1 ) among all hydrocarbons (Richard and Ball, 2008). However, methane also is a potent greenhouse gas (Hanson and Hanson, 1996) and, predominantly due to changing agricultural practices (e.g., increased development of rice production and livestock cultivation) over the past two centuries, the atmospheric concentration of methane has more than doubled, reaching a level (1770 ppb in 2005) that far exceeds the natural range (320–790 ppb) of the last 650,000 years (Wuebbles and Hayhoe, 2000). Therefore, because of the effect of greenhouse gases on climate change, understanding the basis of methane production is an important research goal, while controlling methane emissions is an important aim for governmental policy makers.…”

Section: Introductionmentioning

confidence: 99%

In vivo activation of methyl-coenzyme M reductase by carbon monoxide

Zhou¹,

Dorchak²,

Ragsdale³

2013

Front. Microbiol.

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Methyl-coenzyme M reductase (MCR) from methanogenic archaea catalyzes the rate-limiting and final step in methane biosynthesis. Using coenzyme B as the two-electron donor, MCR reduces methyl-coenzyme M (CH3-SCoM) to methane and the mixed disulfide, CoBS-SCoM. MCR contains an essential redox-active nickel tetrahydrocorphinoid cofactor, Coenzyme F430, at its active site. The active form of the enzyme (MCRred1) contains Ni(I)-F430. Rapid and efficient conversion of MCR to MCRred1 is important for elucidating the enzymatic mechanism, yet this reduction is difficult because the Ni(I) state is subject to oxidative inactivation. Furthermore, no in vitro methods have yet been described to convert Ni(II) forms into MCRred1. Since 1991, it has been known that MCRred1 from Methanothermobacter marburgensis can be generated in vivo when cells are purged with 100% H2. Here we show that purging cells or cell extracts with CO can also activate MCR. The rate of in vivo activation by CO is about 15 times faster than by H2 (130 and 8 min-1, respectively) and CO leads to twofold higher MCRred1 than H2. Unlike H2-dependent activation, which exhibits a 10-h lag time, there is no lag for CO-dependent activation. Based on cyanide inhibition experiments, carbon monoxide dehydrogenase is required for the CO-dependent activation. Formate, which also is a strong reductant, cannot activate MCR in M. marburgensis in vivo.

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Atmospheric Methane: Trends and Impacts

Cited by 15 publications

References 164 publications

The Distribution of Dissolved Methane and Its Air-Sea Flux in the Plume of a Seep Field, Lingtou Promontory, South China Sea

The Distribution of Dissolved Methane and Its Air-Sea Flux in the Plume of a Seep Field, Lingtou Promontory, South China Sea

Space-borne observation of methane from atmospheric infrared sounder: data analysis and distribution over Iraq

In vivo activation of methyl-coenzyme M reductase by carbon monoxide

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