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Atmospheric methane
About: Atmospheric methane is a research topic. Over the lifetime, 2034 publications have been published within this topic receiving 119616 citations.
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TL;DR: In the Arctic, methane gas hydrates represent a significant source of methane, which may become more important if Arctic warming occurs as part of global climate change as discussed by the authors, and the danger of a thermal runway caused by CH4 release from permafrost is minor, but real.
Abstract: Northern sources, including wetlands and perhaps gas hydrates, contribute significantly to the CH4 content of the atmosphere. Methane production from northern wetlands, including bogs, swamps, and ponds, is probably very seasonal, being most important in late summer, with significant evasion in autumn as lakes overturn. The strong recovery of beaver populations in Canada, from near-extinction 50 years ago to present abundance, may also be important, both in creating new wetlands and in the alteration of them; wetlands that have been altered by beaver activity produce orders of magnitude more methane than beaver-free wetlands. In the Arctic, methane gas hydrates represent a significant source of methane, which may become more important if Arctic warming occurs as part of global climate change. The danger of a thermal runway caused by CH4 release from permafrost is minor, but real. Other high-latitude sources of CH4 include Arctic peat bogs, and losses from natural gas production, especially in the Soviet U...
69 citations
TL;DR: In this paper, the authors made measurements of net methane flux during the 1988 ice-free season (May-October) at a beaver-meadow complex in northern Minnesota, USA.
Abstract: Measurements of net methane flux were made during the 1988 ice-free season (May–October) at a beaver-meadow complex in northern Minnesota, USA. The site included upland boreal forest, sedge meadow, submerged aquatic plants, and the open water of a beaver pond. Annual fluxes were 8–11 g C/m2 in the permanently wetted zones and 0.2–0.4 g C/m2 at the occasionally inundated meadow and forest sites. These data, when coupled with long-term (46 yr) data on beaver (Castor canadensis) population size and habitat alteration, suggest that about 1% of the recent rise in atmospheric methane may be attributable to pond creation by beaver in North America.
69 citations
TL;DR: The Neoarchean likely represented a unique state of the Earth system where haze development played a pivotal role in planetary oxidation, hastening the contingent biological innovations that followed.
Abstract: Emerging evidence suggests that atmospheric oxygen may have varied before rising irreversibly ∼2.4 billion years ago, during the Great Oxidation Event (GOE). Significantly, however, pre-GOE atmospheric aberrations toward more reducing conditions-featuring a methane-derived organic-haze-have recently been suggested, yet their occurrence, causes, and significance remain underexplored. To examine the role of haze formation in Earth's history, we targeted an episode of inferred haze development. Our redox-controlled (Fe-speciation) carbon- and sulfur-isotope record reveals sustained systematic stratigraphic covariance, precluding nonatmospheric explanations. Photochemical models corroborate this inference, showing Δ36S/Δ33S ratios are sensitive to the presence of haze. Exploiting existing age constraints, we estimate that organic haze developed rapidly, stabilizing within ∼0.3 ± 0.1 million years (Myr), and persisted for upward of ∼1.4 ± 0.4 Myr. Given these temporal constraints, and the elevated atmospheric CO2 concentrations in the Archean, the sustained methane fluxes necessary for haze formation can only be reconciled with a biological source. Correlative δ13COrg and total organic carbon measurements support the interpretation that atmospheric haze was a transient response of the biosphere to increased nutrient availability, with methane fluxes controlled by the relative availability of organic carbon and sulfate. Elevated atmospheric methane concentrations during haze episodes would have expedited planetary hydrogen loss, with a single episode of haze development providing up to 2.6-18 × 1018 moles of O2 equivalents to the Earth system. Our findings suggest the Neoarchean likely represented a unique state of the Earth system where haze development played a pivotal role in planetary oxidation, hastening the contingent biological innovations that followed.
69 citations
TL;DR: In this paper, the authors studied the hydrographic regime of the Hakon Mosby mud volcano to evaluate its influence on the distribution pattern of methane as it is shown by the concentration gradients.
69 citations
TL;DR: In this article, a study was conducted to determine whether temperate wetlands and forests play important roles in the global balances of atmospheric methane, and the authors found that wetland sites acted as small sources of atmospheric Methane, with emission rates for methane usually lower than 200 mg CH4/sq m per day.
Abstract: This study was conducted to determine whether temperate wetlands and forests play important roles in the global balances of atmospheric methane. Flux measurements for methane in several different wetland, forest, and open-water (e.g., beaver pond and low-order stream) sites were determined using collection chambers placed over the soil- or water-air interface. All of the sites were located in the Appalachian Mountain region of West Virginia and western Maryland. Between June 1987 and April 1989 the wetland sites acted as small sources of atmospheric methane, with emission rates for methane usually lower than 200 mg CH4/sq m per day; consumption of atmospheric methane in the wetland soils was observed frequently.
69 citations