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Sample records for bay potb methane

  1. Evaluating Bay Area Methane Emission Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jeong, Seongeun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-03-01

    As a regulatory agency, evaluating and improving estimates of methane (CH4) emissions from the San Francisco Bay Area is an area of interest to the Bay Area Air Quality Management District (BAAQMD). Currently, regional, state, and federal agencies generally estimate methane emissions using bottom-up inventory methods that rely on a combination of activity data, emission factors, biogeochemical models and other information. Recent atmospheric top-down measurement estimates of methane emissions for the US as a whole (e.g., Miller et al., 2013) and in California (e.g., Jeong et al., 2013; Peischl et al., 2013) have shown inventories underestimate total methane emissions by ~ 50% in many areas of California, including the SF Bay Area (Fairley and Fischer, 2015). The goal of this research is to provide information to help improve methane emission estimates for the San Francisco Bay Area. The research effort builds upon our previous work that produced methane emission maps for each of the major source sectors as part of the California Greenhouse Gas Emissions Measurement (CALGEM) project (http://calgem.lbl.gov/prior_emission.html; Jeong et al., 2012; Jeong et al., 2013; Jeong et al., 2014). Working with BAAQMD, we evaluate the existing inventory in light of recently published literature and revise the CALGEM CH4 emission maps to provide better specificity for BAAQMD. We also suggest further research that will improve emission estimates. To accomplish the goals, we reviewed the current BAAQMD inventory, and compared its method with those from the state inventory from the California Air Resources Board (CARB), the CALGEM inventory, and recent published literature. We also updated activity data (e.g., livestock statistics) to reflect recent changes and to better represent spatial information. Then, we produced spatially explicit CH4 emission estimates on the 1-km modeling grid used by BAAQMD. We present the detailed activity data, methods and derived emission maps by sector

  2. Distribution of methane in the Lena Delta and Buor-Khaya Bay, Russia

    Directory of Open Access Journals (Sweden)

    I. Bussmann

    2013-07-01

    Full Text Available The Lena River is one of the largest Russian rivers draining into the Laptev Sea. The permafrost areas surrounding the Lena are predicted to thaw at increasing rates due to global temperature increases. With this thawing, large amounts of carbon – either organic or in the gaseous forms carbon dioxide and methane – will reach the waters of the Lena and the adjacent Buor-Khaya Bay (Laptev Sea. Methane concentrations and the isotopic signal of methane in the waters of the Lena Delta and estuary were monitored from 2008 to 2010. Creeks draining from permafrost soils produced hotspots for methane input into the river system (median concentration 1500 nM compared with concentrations of 30–85 nM observed in the main channels of the Lena. No microbial methane oxidation could be detected; thus diffusion is the main process of methane removal. We estimated that the riverine diffusive methane flux is 3–10 times higher than the flux from surrounding terrestrial environment. To maintain the observed methane concentrations in the river, additional methane sources are necessary. The methane-rich creeks could be responsible for this input. In the estuary of Buor-Khaya Bay, methane concentrations decreased to 26–33 nM. However, within the bay no consistent temporal and spatial pattern could be observed. The methane-rich waters of the river were not diluted with marine water because of a strong stratification of the water column. Thus, methane is released from the estuary and from the river mainly by diffusion into the atmosphere.

  3. Methane and nitrous oxide emissions from a subtropical coastal embayment (Moreton Bay, Australia).

    Science.gov (United States)

    Musenze, Ronald S; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

    2015-03-01

    Surface water methane (CH4) and nitrous oxide (N2O) concentrations and fluxes were investigated in two subtropical coastal embayments (Bramble Bay and Deception Bay, which are part of the greater Moreton Bay, Australia). Measurements were done at 23 stations in seven campaigns covering different seasons during 2010-2012. Water-air fluxes were estimated using the Thin Boundary Layer approach with a combination of wind and currents-based models for the estimation of the gas transfer velocities. The two bays were strong sources of both CH4 and N2O with no significant differences in the degree of saturation of both gases between them during all measurement campaigns. Both CH4 and N2O concentrations had strong temporal but minimal spatial variability in both bays. During the seven seasons, CH4 varied between 500% and 4000% saturation while N2O varied between 128 and 255% in the two bays. Average seasonal CH4 fluxes for the two bays varied between 0.5±0.2 and 6.0±1.5 mg CH4/(m2·day) while N2O varied between 0.4±0.1 and 1.6±0.6 mg N2O/(m2·day). Weighted emissions (t CO2-e) were 63%-90% N2O dominated implying that a reduction in N2O inputs and/or nitrogen availability in the bays may significantly reduce the bays' greenhouse gas (GHG) budget. Emissions data for tropical and subtropical systems is still scarce. This work found subtropical bays to be significant aquatic sources of both CH4 and N2O and puts the estimated fluxes into the global context with measurements done from other climatic regions. Copyright © 2014. Published by Elsevier B.V.

  4. Magnitude and seasonality of wetland methane emissions from the Hudson Bay Lowlands (Canada

    Directory of Open Access Journals (Sweden)

    C. A. Pickett-Heaps

    2011-04-01

    Full Text Available The Hudson Bay Lowlands (HBL is the second largest boreal wetland ecosystem in the world and an important natural source of global atmospheric methane. We quantify the HBL methane emissions by using the GEOS-Chem chemical transport model to simulate aircraft measurements over the HBL from the ARCTAS and pre-HIPPO campaigns in May–July 2008, together with continuous 2004–2008 surface observations at Fraserdale (southern edge of HBL and Alert (Arctic background. The difference in methane concentrations between Fraserdale and Alert is shown to be a good indicator of HBL emissions, and implies a sharp seasonal onset of emissions in late May (consistent with the aircraft data, a peak in July–August, and a seasonal shut-off in September. The model, in which seasonal variation of emission is mainly driven by surface temperature, reproduces well the observations in summer but its seasonal shoulders are too broad. We suggest that this reflects the suppression of emissions by snow cover and greatly improve the model simulation by accounting for this effect. Our resulting best estimate for HBL methane emissions is 2.3 Tg a−1, several-fold higher than previous estimates (Roulet et al., 1994; Worthy et al., 2000.

  5. Magnitude and Seasonality of Wetland Methane Emissions from the Hudson Bay Lowlands (Canada)

    Science.gov (United States)

    Pickett-Heaps, C. A.; Jacob, D. J.; Wecht, K. J.; Kort, E. A.; Wofsy, S. C.; Diskin, G. S.; Worthy, D. E. J.; Kaplan, J. O.; Bey, I.; Drevet, J.

    2011-01-01

    The Hudson Bay Lowlands (HBL) is the second largest boreal wetland ecosystem in the world and an important natural source of global atmospheric methane. We quantify the HBL methane emissions by using the GEOS-Chem chemical transport model to simulate aircraft measurements over the HBL from the ARCTAS and pre-HIPPO campaigns in May-July 2008, together with continuous 2004-2008 surface observations at Fraserdale (southern edge of HBL) and Alert (Arctic background). The difference in methane concentrations between Fraserdale and Alert is shown to be a good indicator of HBL emissions, and implies a sharp seasonal onset of emissions in late May (consistent with the aircraft data), a peak in July-August, and a seasonal shut-off in September. The model, in which seasonal variation of emission is mainly driven by surface temperature, reproduces well the observations in summer but its seasonal shoulders are too broad. We suggest that this reflects the suppression of emissions by snow cover and greatly improve the model simulation by accounting for this effect. Our resulting best estimate for HBL methane emissions is 2.3 Tg/a, several-fold higher than previous estimates (Roulet et al., 1994; Worthy et al., 2000).

  6. Airborne Quantification of Methane Emissions in the San Francisco Bay Area of California

    Science.gov (United States)

    Guha, A.; Newman, S.; Martien, P. T.; Young, A.; Hilken, H.; Faloona, I. C.; Conley, S.

    2017-12-01

    The Bay Area Air Quality Management District, the San Francisco Bay Area's air quality regulatory agency, has set a goal to reduce the region's greenhouse gas (GHG) emissions 80% below 1990 levels by 2050, consistent with the State of California's climate protection goal. The Air District maintains a regional GHG emissions inventory that includes emissions estimates and projections which influence the agency's programs and regulatory activities. The Air District is currently working to better characterize methane emissions in the GHG inventory through source-specific measurements, to resolve differences between top-down regional estimates (Fairley and Fischer, 2015; Jeong et al., 2016) and the bottom-up inventory. The Air District funded and participated in a study in Fall 2016 to quantify methane emissions from a variety of sources from an instrumented Mooney aircraft. This study included 40 hours of cylindrical vertical profile flights that combined methane and wind measurements to derive mass emission rates. Simultaneous measurements of ethane provided source-apportionment between fossil-based and biological methane sources. The facilities sampled included all five refineries in the region, five landfills, two dairy farms and three wastewater treatment plants. The calculated mass emission rates were compared to bottom-up rates generated by the Air District and to those from facility reports to the US EPA as part of the mandatory GHG reporting program. Carbon dioxide emission rates from refineries are found to be similar to bottom-up estimates for all sources, supporting the efficacy of the airborne measurement methodology. However, methane emission estimates from the airborne method showed significant differences for some source categories. For example, methane emission estimates based on airborne measurements were up to an order of magnitude higher for refineries, and up to five times higher for landfills compared to bottom-up methods, suggesting significant

  7. Environmental control on anaerobic oxidation of methane in the gassy sediments of Eckernforde Bay (German Baltic)

    DEFF Research Database (Denmark)

    Treude, T.; Kruger, M.; Boetius, A.

    2005-01-01

    and March. Field rates of AOM and sulfate reduction (SR) were measured with radiotracer methods. Additional parameters were determined that potentially influence AOM, i.e., temperature, salinity, methane, sulfate, and chlorophyll a. Methanogenesis as well as potential rates of AOM and aerobic oxidation...

  8. Discovery of Widespread Biogenic Methane Emissions and Authigenic Carbonate Mound-like Structures at the Aquitaine Shelf (Bay of Biscay)

    Science.gov (United States)

    Dupré, S.; Loubrieu, B.; Scalabrin, C.; Ehrhold, A.; Gautier, E.; Ruffine, L.; Pierre, C.; Battani, A.; Le Bouffant, N.; Berger, L.

    2014-12-01

    Fishery acoustic surveys conducted in the Bay of Biscay (1998-2012) and dedicated to monitoring and predicting pelagic ecosystem evolution reveal numerous active seeps on the Aquitaine Shelf, east of the shelf break (Dupré et al. 2014). Seafloor and water column acoustic investigation with the use of ship-borne multibeam echosounder in 2013 (Gazcogne1 marine expedition) confirmed the presence of numerous (> 3000) persistent and widespread gas emission sites at water depths ranging from ~140 to 180 m. These fluid emissions are associated at the seafloor with high backscatter subcircular small-scale mounds, on average less than 2 m high and a few meters in diameter. Near-bottom visual observations and samplings were conducted with the ROV (Remotely Operated Vehicle) Victor (Gazcogne2 expedition). The whole mounds cover an area of ~200 km2 of the seabed, and are by-products of gas seepage, i.e. methane-derived authigenic carbonates. The spatial distribution of the seeps and related structures, based on water column acoustic gas flares and high backscatter seabed patches, appears to be relatively broad, with a North-South extension of ~80 km across the Parentis Basin and the Landes High, and a West-East extension along a few kilometers wide on the shelf, up to 8 km. Gas bubbles sampled at in situ conditions are principally composed of biogenic methane, possibly originated from Late Pleistocene deposits. The volume of methane emitted into the water column is abundant i) with an average gas flux varying locally from 0.035 to 0.37 Ln/min and ii) with regard to the time needed for the precipitation of the authigenic carbonates identified both at the seabed and in the upper most sedimentary column. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. ReferenceDupré, S., Berger, L., Le Bouffant, N., Scalabrin, C., and Bourillet, J.-F., 2014. Fluid emissions at the Aquitaine Shelf (Bay of

  9. Gas hydrate destabilization and methane release events in the Krishna-Godavari Basin, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Joshi, R.K.; Mazumdar, A.; Peketi, A.; Ramamurty, P.B.; Naik, B.G.; Kocherla, M.; Carvalho, M.A.; Mahalakshmi, P.; Dewangan, P.; Ramana, M.V.

    foraminifera to 13C depleted bicarbonate ion produced via     aerobic/ anaerobic oxidation of methane in water column/ sediment-water interface, a significant number of publications attribute the 13C depletion to diagenetic alteration of non... for changing the carbon isotope ratios of the shallow water bicarbonate reservoir during P1, P2 and P3 events were apparently decoupled from the deep water bicarbonate pool. Timings of P2 and P3 may correspond to the Dansgaard-Oeschger warming events during...

  10. Long-lasting Microbial Methane Release at the Aquitaine Shelf Break (Bay of Biscay): Relation with the (Plio)-Pleistocene Sedimentary Progradation of the Continental Margin

    Science.gov (United States)

    Dupré, S.; Michel, G.; Pierre, C.; Ruffine, L.; Scalabrin, C.; Ehrhold, A.; Loubrieu, B.; Gautier, E.; Baltzer, A.; Imbert, P.; Battani, A.; Deville, E.; Dupont, P.; Thomas, Y.; Théréau, E.

    2017-12-01

    The recent identification of acoustic and visual gas release in the water column at the Aquitaine Shelf (140 and 220 m water depths) led to the discovery of a 200 km2 fluid system at the seafloor with 3000 bubbling sites associated with microbial methane (Dupré et al 2014; Ruffine et al. 2017). The moderate methane fluxes (measured in situ, on average 200 mLn/min per bubbling site) contribute to the formation of small-scale sub-circular authigenic carbonate mounds (with reliefs emissions at the Aquitaine Shelf (Bay of Biscay, France): a biogenic origin or the expression of hydrocarbon leakage? Cont. Shelf Res. 88:24-33 Pierre C, Demange J, Blanc-Valleron M-M, Dupré S (2017) Authigenic carbonate mounds from active methane seeps on the southern Aquitaine Shelf (Bay of Biscay, France): Evidence for anaerobic oxidation of biogenic methane and submarine groundwater discharge during formation. Cont. Shelf Res. 133:13-25 Ruffine L, Donval J-P, Croguennec C, Bignon L, Birot D, Battani A, Bayon G, Caprais J-C, Lantéri N, Levaché D, Dupré S (2017) Gas Seepage along the Edge of the Aquitaine Shelf (France): Origin and Local Fluxes. Geofluids 2017:13

  11. Enrichment and cultivation of prokaryotes associated with the sulphate-methane transition zone of diffusion-controlled sediments of Aarhus Bay, Denmark, under heterotrophic conditions.

    Science.gov (United States)

    Webster, Gordon; Sass, Henrik; Cragg, Barry A; Gorra, Roberta; Knab, Nina J; Green, Christopher J; Mathes, Falko; Fry, John C; Weightman, Andrew J; Parkes, R John

    2011-08-01

    The prokaryotic activity, diversity and culturability of diffusion-controlled Aarhus Bay sediments, including the sulphate-methane transition zone (SMTZ), were determined using a combination of geochemical, molecular (16S rRNA and mcrA genes) and cultivation techniques. The SMTZ had elevated sulphate reduction and anaerobic oxidation of methane, and enhanced cell numbers, but no active methanogenesis. The prokaryotic population was similar to that in other SMTZs, with Deltaproteobacteria, Gammaproteobacteria, JS1, Planctomycetes, Chloroflexi, ANME-1, MBG-D and MCG. Many of these groups were maintained in a heterotrophic (10 mM glucose, acetate), sediment slurry with periodic low sulphate and acetate additions (~2 mM). Other prokaryotes were also enriched including methanogens, Firmicutes, Bacteroidetes, Synergistetes and TM6. This slurry was then inoculated into a matrix of substrate and sulphate concentrations for further selective enrichment. The results demonstrated that important SMTZ bacteria can be maintained in a long-term, anaerobic culture under specific conditions. For example, JS1 grew in a mixed culture with acetate or acetate/glucose plus sulphate. Chloroflexi occurred in a mixed culture, including in the presence of acetate, which had previously not been shown to be a Chloroflexi subphylum I substrate, and was more dominant in a medium with seawater salt concentrations. In contrast, archaeal diversity was reduced and limited to the orders Methanosarcinales and Methanomicrobiales. These results provide information about the physiology of a range of SMTZ prokaryotes and shows that many can be maintained and enriched under heterotrophic conditions, including those with few or no cultivated representatives. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  12. Dissolved methane during hypoxic events at the Boknis Eck time series station (Eckernförde Bay, SW Baltic Sea

    Directory of Open Access Journals (Sweden)

    H. W. Bange

    2010-04-01

    Full Text Available Dissolved CH4 was measured in the water column at the Boknis Eck (BE time series station in the Eckernförde Bay (SW Baltic Sea on a monthly basis from June 2006 to November 2008. The water column at BE was always supersaturated with CH4 and, therefore, CH4 was released to the atmosphere throughout the sampling period: the mean CH4 surface (1 m saturation at BE was 554±317%. A pulse of enhanced CH4 emissions occurs when the CH4 accumulation in the hypoxic bottom layer during summer is terminated in late summer/autumn. We did not detect a straightforward relationship between periods of enhanced CH4 in the bottom layer and hypoxic events at BE: the sedimentary release of CH4 seemed to be mainly triggered by sedimenting organic material from phytoplankton blooms. We conclude that future CH4 emissions from BE will be determined by the intensity of phytoplankton blooms, which in turn will be influenced by eutrophication. However, hypoxic events seem to have only a modulating effect on the enhancement of sedimentary methanogenesis and the subsequent release of CH4 to the water column.

  13. Dissolved methane during hypoxic events at the Boknis Eck time series station (Eckernförde Bay, SW Baltic Sea)

    Science.gov (United States)

    Bange, H. W.; Bergmann, K.; Hansen, H. P.; Kock, A.; Koppe, R.; Malien, F.; Ostrau, C.

    2010-04-01

    Dissolved CH4 was measured in the water column at the Boknis Eck (BE) time series station in the Eckernförde Bay (SW Baltic Sea) on a monthly basis from June 2006 to November 2008. The water column at BE was always supersaturated with CH4 and, therefore, CH4 was released to the atmosphere throughout the sampling period: the mean CH4 surface (1 m) saturation at BE was 554±317%. A pulse of enhanced CH4 emissions occurs when the CH4 accumulation in the hypoxic bottom layer during summer is terminated in late summer/autumn. We did not detect a straightforward relationship between periods of enhanced CH4 in the bottom layer and hypoxic events at BE: the sedimentary release of CH4 seemed to be mainly triggered by sedimenting organic material from phytoplankton blooms. We conclude that future CH4 emissions from BE will be determined by the intensity of phytoplankton blooms, which in turn will be influenced by eutrophication. However, hypoxic events seem to have only a modulating effect on the enhancement of sedimentary methanogenesis and the subsequent release of CH4 to the water column.

  14. Pore-water chemistry of sediment cores off Mahanadi Basin, Bay of Bengal: Possible link to deep seated methane hydrate deposit

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumdar, A.; Peketi, A.; Joao, H.M.; Dewangan, P.; Ramprasad, T.

    Organoclastic degradation and anaerobic oxidation of methane (AOM) are known to influence sulfate, methane and bicarbonate concentrations of sediment pore-waters. In this work we have analyzed the pore-fluid composition of three piston cores (36e39...

  15. Formation of methane-related authigenic carbonates in a highly dynamic biogeochemical system in the Krishna–Godavari Basin, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Kocherla, M.; Teichert, B.M.A.; Pillai, S.; Satyanarayan, M.; Ramamurty, P.B.; Patil, D.J.; Rao, A.N.

    (2) During both biogeochemical processes bicarbonate [HCO3-] is being produced and thus pore water alkalinity increases. This will lead together with seawater calcium to the precipitation of authigenic carbonate minerals (equation 3). Ca2+ + 2...). This is also the zone where methane-related authigenic carbonates will form due to the production of bicarbonate and increase in alkalinity. Characteristic low carbon isotope ratios of methane-related carbonates have been identified at Sites 1, 5, 8, 9, 12...

  16. Arctic methane

    NARCIS (Netherlands)

    Dyupina, E.; Amstel, van A.R.

    2013-01-01

    What are the risks of a runaway greenhouse effect from methane release from hydrates in the Arctic? In January 2013, a dramatic increase of methane concentration up to 2000 ppb has been measured over the Arctic north of Norway in the Barents Sea. The global average being 1750 ppb. It has been

  17. Breaking methane

    OpenAIRE

    Rosenzweig, Amy C.

    2015-01-01

    The most powerful oxidant found in nature is compound Q, an enzymatic intermediate that oxidizes methane. New spectroscopic data have resolved the long-running controversy about Q’s chemical structure.

  18. Agricultural methanization

    International Nuclear Information System (INIS)

    2011-01-01

    After having briefly outlined the interest of the development of methanization of agricultural by-products in the context of struggle against climate change, and noticed that France is only now developing this sector as some other countries already did, this publication describes the methanization process also called anaerobic digestion, which produces a digestate and biogas. Advantages for the agriculture sector are outlined, as well as drawbacks and recommendations (required specific technical abilities, an attention to the use of energetic crops, an improved economic balance which still depends on public subsidies, competition in the field of waste processing). Actions undertaken by the ADEME are briefly evoked

  19. [Microbial Processes and Genesis of Methane Gas Jets in the Coastal Areas of the Crimea Peninsula].

    Science.gov (United States)

    Malakhova, T V; Kanapatskii, T A; Egorov, V N; Malakhova, L V; Artemov, Yu G; Evtushenko, D B; Gulin, S B; Pimenov, N V

    2015-01-01

    Hydroasoustic techniques were used for detection and mapping of gas jet areas in the coastal regions of the Crimean peninsula. Gas seep areas in the bays Laspi, Khersones, and Kazach'ya were chosen for detailed microbiological investigation. The first type of gas jets, observed in the Laspi Bay, was probably associated with discarge of deep thermogenic methane along the faults. Methane isotopic composition was char- acterized by Δ13C of -35.3 degrees. While elevated rates of aerobic methane oxidation were revealed in the sandy sediments adjacent to the methane release site, no evidence of bacterial mats was found. The second type of gas emission, observed in the Khersones Bay, was accompanied by formation of bacterial biofilms of the "Thiodendron" microbial community type, predominated by filamentous, spirochete-like organisms, in the areas of gas seepage. The isotopic composition of methane was there considerably lower (-60.4 degrees), indicating a considerable contribution of modern microbial methane to the gas bubbles discharged in this bay. Activity of the third type of gas emission, the seeps of the Kazach'ya Bay, probably depended directly on modern microbial processes of organic matter degradation in the upper sediment layers. The rates of sulfate reduction and methanogenesis were 260 and 34 μmol dm(-3) day(-1), respectively. Our results indicate different mechanisms responsible for formation of methane jets in the Laspi Bay and in the coastal areas of the Heracles Peninsula, where the bays Kazach'ya and Khersones are located.

  20. Landfill Methane

    Science.gov (United States)

    Landfill methane (CH4) accounts for approximately 1.3% (0.6 Gt) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49 Gt CO2-eq yr-1. For countries with a history of controlled landfilling, landfills can be one of the larger national sources of ant...

  1. Coalbed Methane Outreach Program

    Science.gov (United States)

    Coalbed Methane Outreach Program, voluntary program seeking to reduce methane emissions from coal mining activities. CMOP promotes profitable recovery/use of coal mine methane (CMM), addressing barriers to using CMM instead of emitting it to atmosphere.

  2. Methane and fertilizer production from seaweed biomass. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Betzer, P.R.; Humm, H.J.

    1984-01-01

    It was demonstrated that several varieties of abundant benthic algae indigenous to Tampa Bay (Gracilaria, Hypnea, and Ulva) were readily degradable via anaerobic digestion to methane. The energy yield per unit weight biomass degraded was higher than any previously reported. Given the large masses of readily degradable plants which are annually produced in and around Tampa Bay, the resource is estimated to be at least equivalent to several million gallons of gasoline.

  3. Mex Bay

    African Journals Online (AJOL)

    user

    2015-02-23

    Feb 23, 2015 ... surveys to assess the vulnerability of the most important physical and eutrophication parameters along. El- Mex Bay coast. As a result of increasing population and industrial development, poorly untreated industrial waste, domestic sewage, shipping industry and agricultural runoff are being released to the.

  4. Global Methane Initiative

    Science.gov (United States)

    The Global Methane Initiative promotes cost-effective, near-term methane recovery through partnerships between developed and developing countries, with participation from the private sector, development banks, and nongovernmental organizations.

  5. Methane distribution and transportation in Lake Chaohu: a shallow eutrophic lake in Eastern China

    Science.gov (United States)

    Zhang, L.; Shen, Q.

    2016-12-01

    Global warming and eutrophication are two world widely concerned environmental problems. Methane is the second important greenhouse gas, and lake has been proven as a quite important natural source of methane emission. More methane may emit from eutrophic lake due to the higher organic matter deposition in the lake sediment. Lake Chaohu is a large and shallow eutrophic lake in eastern China (N31°25' 31°43', E117°16' 117°05'), with an area of 770 km2 and a mean depth of 2.7 m. To examine methane distribution and transportation in this eutrophic lake, field study across different seasons was carried out with 20 study sites in the lake. Samples from the different water and sediment depth was collected using headspace bottle, and methane content was measured by gas chromatography using a flame ionization detector. The potential methane production in the sediment was examined by an indoor incubation experiment. Methane flux from sediment to the overlying water was calculated by Fick's law, and methane emission from surface to the air was calculated at the same time. The results indicates that more methane accumulated in the water of northwestern bay in this lake, and higher methane release rates was also found at this area. Methane increases gradually with depth in the top 10 cm in sediment cores, then it almost keeps at constant state in the deeper sediment. In the sediment from northwestern bay, more methane content and the higher potential methane production was found compared to the sediment from the east area of this lake.

  6. Investigations of Methane Production in Hypersaline Environments

    Science.gov (United States)

    Bebout, Brad M.

    2015-01-01

    The recent reports of methane in the atmosphere of Mars, as well as the findings of hypersaline paleo-environments on that planet, have underscored the need to evaluate the importance of biological (as opposed to geological) trace gas production and consumption. Methane in the atmosphere of Mars may be an indication of life but might also be a consequence of geologic activity and/or the thermal alteration of ancient organic matter. Hypersaline environments have now been reported to be extremely likely in several locations in our solar system, including: Mars, Europa, and Enceladus. Modern hypersaline microbial mat communities, (thought to be analogous to those present on the early Earth at a period of time when Mars was experiencing very similar environmental conditions), have been shown to produce methane. However, very little is known about the physical and/or biological controls imposed upon the rates at which methane, and other important trace gases, are produced and consumed in these environments. We describe here the results of our investigations of methane production in hypersaline environments, including field sites in Chile, Baja California Mexico, California, USA and the United Arab Emirates. We have measured high concentrations of methane in bubbles of gas produced both in the sediments underlying microbial mats, as well as in areas not colonized by microbial mats in the Guerrero Negro hypersaline ecosystem, Baja California Mexico, in Chile, and in salt ponds on the San Francisco Bay. The carbon isotopic (d13C) composition of the methane in the bubbles exhibited an extremely wide range of values, (ca. -75 per mille ca. -25 per mille). The hydrogen isotopic composition of the methane (d2H) ranged from -60 to -30per mille and -450 to -350per mille. These isotopic values are outside of the range of values normally considered to be biogenic, however incubations of the sediments in contact with these gas bubbles reveals that the methane is indeed being

  7. Sources of atmospheric methane from coastal marine wetlands

    International Nuclear Information System (INIS)

    Harriss, R.C.; Sebacher, D.I.; Bartlett, K.B.; Bartlett, D.S.

    1982-01-01

    Biological methanogenesis in wetlands is believed to be one of the major sources of global tropospheric methane. The present paper reports measurements of methane distribution in the soils, sediments, water and vegetation of coastal marine wetlands. Measurements, carried out in the salt marshes Bay Tree Creek in Virginia and Panacea in northwest Florida, reveal methane concentrations in soils and sediments to vary with depth below the surface and with soil temperature. The fluxes of methane from marsh soils to the atmosphere at the soil-air interface are estimated to range from -0.00067 g CH 4 /sq m per day (methane sink) to 0.024 g CH 4 /sq m per day, with an average value of 0.0066 g CH 4 /sq m per day. Data also demonstrate the important role of tidal waters percolating through marsh soils in removing methane from the soils and releasing it to the atmosphere. The information obtained, together with previous studies, provides a framework for the design of a program based on in situ and remote sensing measurements to study the global methane cycle

  8. Doses from radioactive methane

    International Nuclear Information System (INIS)

    Phipps, A.W.; Kendall, G.M.; Fell, T.P.; Harrison, J.D.

    1990-01-01

    A possible radiation hazard arises from exposure to methane labelled with either a 3 H or a 14 C nuclide. This radioactive methane could be released from a variety of sources, e.g. land burial sites containing radioactive waste. Standard assumptions adopted for vapours would not apply to an inert alkane like methane. This paper discusses mechanisms by which radioactive methane would irradiate tissues and provides estimates of doses. Data on skin thickness and metabolism of methane are discussed with reference to these mechanisms. It is found that doses are dominated by dose from the small fraction of methane which is inhaled and metabolised. This component of dose has been calculated under rather conservative assumptions. (author)

  9. Tracing the Paleo sulfate-methane transition zones and H2S seepage events in marine sediments: An application of C-S-Mo systematics

    Digital Repository Service at National Institute of Oceanography (India)

    Peketi, A.; Mazumdar, A.; Joshi, R.K.; Patil, D.J.; Srinivas, P.L.; Dayal, A.M.

    sub(4)) events through geologic time. Here, we present results from carbonate carbon, pyrite sulfur and molybdenum analyses for two sediment cores overlying the methane hydrate deposits in the Bay of Bengal. The results show intimate association...

  10. Minimizing methane release

    NARCIS (Netherlands)

    Arendonk, van J.A.M.

    2014-01-01

    "Methane emissions from cows are decreasing, but not at the pace which the agricultural sector and the government agreed. The project, Reduced methane emission of dairy cows (ME001), will provide insights that enable targeted interventions for a 30% reduction of greenhouse gasses in the Netherlands

  11. Methane and Climate Change

    NARCIS (Netherlands)

    Reay, D.; Smith, P.; Amstel, van A.R.

    2010-01-01

    Methane is a powerful greenhouse gas and is estimated to be responsible for approximately one-fifth of man-made global warming. Per kilogram, it is 25 times more powerful than carbon dioxide over a 100-year time horizon -- and global warming is likely to enhance methane release from a number of

  12. Utilization of coalbed methane

    Energy Technology Data Exchange (ETDEWEB)

    Gustavson, J.B. [Gustavson Associates Inc., Boulder, CO (United States)

    1996-02-01

    Substantial progress has been made in capturing coalbed methane (CBM gas), which constitutes a valuable source of clean burning energy. It is of importance to study the various potential uses of coalbed methane and to understand the various technologies required, as well as their economics and any institutional constraints. In industrialised countries, the uses of coalbed methane are almost solely dependent on microeconomics; coalbed methane must compete for a market against natural gas and other energy sources - and frequently, coalbed methane is not competitive against other energy sources. In developing countries, on the other hand, particularly where other sources of energy are in short supply, coalbed methane economics yield positive results. Here, constraints to development of CBM utilization are mainly lack of technology and investment capital. Sociological aspects such as attitude and cultural habits, may also have a strong negative influence. This paper outlines the economics of coalbed methane utilization, particularly its competition with natural gas, and touches upon the many different uses to which coalbed methane may be applied. 24 refs., 4 figs.

  13. Methane in the Sevastopol coastal area, Black Sea

    Science.gov (United States)

    Malakhova, Lyudmila V.; Egorov, Viktor N.; Malakhova, Tatiana V.; Gulin, Sergey B.; Artemov, Yury G.

    2010-06-01

    Concentrations of dissolved methane in seawater and bottom sediments, as well as of methane emanating from gas seeps were measured at 18 stations including several small bays in the Sevastopol coastal area (Black Sea) during 2007-2008. Methane concentrations in surface waters ranged from 10 to 2,970 nmol l-1, and correlated well with values recorded for sediments. Methane concentrations in the water column were influenced by water depth, as well as by air and water temperatures. In the spring and summer of 2008, in situ CH4 saturation relative to air was in the range of 970-71,900%. Maximum saturation was in summer. CH4 fluxes to the atmosphere from the Sevastopol coastal area were estimated to vary from 190 to 1,550 μmol m-2 day-1. Gas bubbles escaping from the seepages contained about 57 vol% methane. Radiocarbon dating of the methane revealed an age not exceeding 150 years, implying a biogenic origin.

  14. Methane Emission by Camelids

    Science.gov (United States)

    Dittmann, Marie T.; Runge, Ullrich; Lang, Richard A.; Moser, Dario; Galeffi, Cordula; Kreuzer, Michael; Clauss, Marcus

    2014-01-01

    Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg−1 d−1) when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg−1 d−1). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg−1 in camelids vs. 86.2±12.1 L kg−1 in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels. PMID:24718604

  15. Methane emission by camelids.

    Directory of Open Access Journals (Sweden)

    Marie T Dittmann

    Full Text Available Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total, all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg⁻¹ d⁻¹ when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg⁻¹ d⁻¹. However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg⁻¹ in camelids vs. 86.2±12.1 L kg⁻¹ in ruminants. This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels.

  16. Methane emission by camelids.

    Science.gov (United States)

    Dittmann, Marie T; Runge, Ullrich; Lang, Richard A; Moser, Dario; Galeffi, Cordula; Kreuzer, Michael; Clauss, Marcus

    2014-01-01

    Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.32±0.11 L kg⁻¹ d⁻¹) when compared to literature data on domestic ruminants fed on roughage diets (0.58±0.16 L kg⁻¹ d⁻¹). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7±33.9 L kg⁻¹ in camelids vs. 86.2±12.1 L kg⁻¹ in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia's feral camels corresponds only to 1 to 2% of the methane amount produced by the countries' domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels.

  17. Chesapeake Bay TMDL Document

    Science.gov (United States)

    This page provides the Total Maximum Daily Load (TMDL) report for the Chesapeake Bay. It includes the executive summary, main report, and appendices. The Chesapeake Bay TMDL was established by U.S. EPA Region 3 on December 29, 2010

  18. Chesapeake Bay TMDL

    Science.gov (United States)

    In 2010 EPA established the Chesapeake Bay TMDL, a comprehensive pollution diet with accountability measures to restore clean water in the bay and local waters. It set limits for nutrients and sediment to meet water quality standards across the watershed

  19. Revival of Archaeal Methane Microbiology.

    Science.gov (United States)

    Welte, Cornelia U

    2018-01-01

    The methane concentration in the Earth's atmosphere is rising, and, as methane is a potent greenhouse gas, it contributes considerably to climate change. It is produced by methanogenic archaea that thrive in anoxic habitats and can be oxidized by methane-oxidizing bacteria or archaea. In this Perspective , recent innovations and discoveries in archaeal methane microbiology are discussed and a future outlook on how novel methane-metabolizing archaea might be cultivated is provided.

  20. Methane prediction in collieries

    CSIR Research Space (South Africa)

    Creedy, DP

    1999-06-01

    Full Text Available The primary aim of the project was to assess the current status of research on methane emission prediction for collieries in South Africa in comparison with methods used and advances achieved elsewhere in the world....

  1. Methane monitoring from space

    Science.gov (United States)

    Stephan, C.; Alpers, M.; Millet, B.; Ehret, G.; Flamant, P.

    2017-11-01

    Methane is one of the strongest anthropogenic greenhouse gases. It contributes by its radiative forcing significantly to the global warming. For a better understanding of climate changes, it is necessary to apply precise space-based measurement techniques in order to obtain a global view on the complex processes that control the methane concentration in the atmosphere. The MERLIN mission is a joint French-German cooperation, on a micro satellite mission for space-based measurement of spatial and temporal gradients of atmospheric methane columns on a global scale. MERLIN will be the first Integrated Path Differential Absorption LIDAR for greenhouse gas monitoring from space. In contrast to passive methane missions, the LIDAR instrument allows measurements at alllatitudes, all-seasons and during night.

  2. Methane Metabolism by Yeast

    Data.gov (United States)

    National Aeronautics and Space Administration — Our Technical Approach is to move the soluble Methane Monooxygenase system (sMMO) from methanotrophic bacteria into Pichi). sMMO consists of a hydroxylase (MMOH)...

  3. Terrestrial plant methane production

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Bruhn, Dan; Møller, Ian M.

    We evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants. We conclude that the phenomenon is true. Four stimulating factors have been observed to induce aerobic plant CH4 production, i.e. cutting injuries, increasing temperature...... the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  4. Dissolved methane in the Beaufort Sea and the Arctic Ocean, 1992-2009; sources and atmospheric flux

    Science.gov (United States)

    Lorenson, Thomas D.; Greinert, Jens; Coffin, Richard B.

    2016-01-01

    Methane concentration and isotopic composition was measured in ice-covered and ice-free waters of the Arctic Ocean during eleven surveys spanning the years of 1992-1995 and 2009. During ice-free periods, methane flux from the Beaufort shelf varies from 0.14 to 0.43 mg CH4 m-2 day-1. Maximum fluxes from localized areas of high methane concentration are up to 1.52 mg CH4 m-2 day-1. Seasonal buildup of methane under ice can produce short-term fluxes of methane from the Beaufort shelf that varies from 0.28 to 1.01 to mg CH4 m-2 day-1. Scaled-up estimates of minimum methane flux from the Beaufort Sea and pan-Arctic shelf for both ice-free and ice-covered periods range from 0.02 Tg CH4 yr-1 and 0.30 Tg CH4 yr-1 respectively to maximum fluxes of 0.18 Tg CH4 yr-1 and 2.2 Tg CH4 yr-1 respectively. A methane flux of 0.36 Tg CH4 yr-1from the deep Arctic Ocean was estimated using data from 1993-94. The flux can be as much as 2.35 Tg CH4 yr-1 estimated from maximum methane concentrations and wind speeds of 12 m/s, representing only 0.42% of the annual atmospheric methane budget of ~560 Tg CH4 yr-1. There were no significant changes in methane fluxes during the time period of this study. Microbial methane sources predominate with minor influxes from thermogenic methane offshore Prudhoe Bay and the Mackenzie River delta and may include methane from gas hydrate. Methane oxidation is locally important on the shelf and is a methane sink in the deep Arctic Ocean.

  5. Direct Activation Of Methane

    KAUST Repository

    Basset, Jean-Marie

    2013-07-15

    Heteropolyacids (HPAs) can activate methane at ambient temperature (e.g., 20.degree. C.) and atmospheric pressure, and transform methane to acetic acid, in the absence of any noble metal such as Pd). The HPAs can be, for example, those with Keggin structure: H.sub.4SiW.sub.12O.sub.40, H.sub.3PW.sub.12O.sub.40, H.sub.4SiMo.sub.12O.sub.40, or H.sub.3PMo.sub.12O.sub.40, can be when supported on silica.

  6. Australian methane fluxes

    International Nuclear Information System (INIS)

    Williams, D.J.

    1990-01-01

    Estimates are provided for the amount of methane emitted annually into the atmosphere in Australia for a variety of sources. The sources considered are coal mining, landfill, motor vehicles, natural gas suply system, rice paddies, bushfires, termites, wetland and animals. This assessment indicates that the major sources of methane are natural or agricultural in nature and therefore offer little scope for reduction. Nevertheless the remainder are not trival and reduction of these fluxes could play a significant part in any Australian action on the greenhouse problem. 19 refs., 7 tabs., 1 fig

  7. Methanization - Technical sheet

    International Nuclear Information System (INIS)

    Bastide, Guillaume

    2015-02-01

    This document explains fundamentals of methanization such as biological reactions and conditions suitable for biogas production (temperature, pH, anaerobic medium, and so on). It also proposes an overview of available techniques, of the present regulation, of environmental impacts, and of costs and profitability of methanization installations. Examples of installations are provided, as well as a set of questions and answers. Perspectives of development are finally discussed in terms of sector development potential, of regulatory evolution, of new perspectives for gas valorisation, of need of acquisition of reference data due to the relatively low number of existing installations, and of research and development

  8. Wakasa Bay Weather Forecast Maps

    Data.gov (United States)

    National Aeronautics and Space Administration — The AMSR-E Wakasa Bay Field Campaign was conducted over Wakasa Bay, Japan, in January and February, 2003. The Wakasa Bay Field Campaign includes joint research...

  9. Methane emissions from grasslands

    NARCIS (Netherlands)

    Pol - van Dasselaar, van den A.

    1998-01-01

    Introduction

    Methane (CH 4 ) is an important greenhouse gas. The concentration of greenhouse gases in the atmosphere has been increasing since pre-industrial times, mainly due to human activities. This increase gives concern,

  10. Variations of trace gases over the Bay of Bengal during the summer ...

    Indian Academy of Sciences (India)

    I A Girach

    2018-02-16

    Feb 16, 2018 ... Tropospheric ozone (O3) and Methane (CH4) are important greenhouse gases with radiative forcing .... 2006). The monthly mean tropospheric O3 (mean volume mixing ratios in ppbv) is used in the present ...... monoxide over Bay of Bengal during winter: Role of water vapour and vertical updrafts; J. Atmos.

  11. eBay.com

    DEFF Research Database (Denmark)

    Engholm, Ida

    2014-01-01

    Celebrated as one of the leading and most valuable brands in the world, eBay has acquired iconic status on par with century-old brands such as Coca-Cola and Disney. The eBay logo is now synonymous with the world’s leading online auction website, and its design is associated with the company...

  12. Project identification for methane reduction options

    Energy Technology Data Exchange (ETDEWEB)

    Kerr, T.

    1996-12-31

    This paper discusses efforts directed at reduction in emission of methane to the atmosphere. Methane is a potent greenhouse gas, which on a 20 year timeframe may present a similar problem to carbon dioxide. In addition, methane causes additional problems in the form of smog and its longer atmospheric lifetime. The author discusses strategies for reducing methane emission from several major sources. This includes landfill methane recovery, coalbed methane recovery, livestock methane reduction - in the form of ruminant methane reduction and manure methane recovery. The author presents examples of projects which have implemented these ideas, the economics of the projects, and additional gains which come from the projects.

  13. Methane emissions from grasslands

    OpenAIRE

    Pol - van Dasselaar, van den, A.

    1998-01-01

    Introduction

    Methane (CH 4 ) is an important greenhouse gas. The concentration of greenhouse gases in the atmosphere has been increasing since pre-industrial times, mainly due to human activities. This increase gives concern, because it may cause global warming due to an enhanced greenhouse effect.

    In the soil, CH 4 may be produced under anaerobic conditions, and consumed under aero...

  14. Coal Bed Methane Primer

    Energy Technology Data Exchange (ETDEWEB)

    Dan Arthur; Bruce Langhus; Jon Seekins

    2005-05-25

    During the second half of the 1990's Coal Bed Methane (CBM) production increased dramatically nationwide to represent a significant new source of income and natural gas for many independent and established producers. Matching these soaring production rates during this period was a heightened public awareness of environmental concerns. These concerns left unexplained and under-addressed have created a significant growth in public involvement generating literally thousands of unfocused project comments for various regional NEPA efforts resulting in the delayed development of public and fee lands. The accelerating interest in CBM development coupled to the growth in public involvement has prompted the conceptualization of this project for the development of a CBM Primer. The Primer is designed to serve as a summary document, which introduces and encapsulates information pertinent to the development of Coal Bed Methane (CBM), including focused discussions of coal deposits, methane as a natural formed gas, split mineral estates, development techniques, operational issues, producing methods, applicable regulatory frameworks, land and resource management, mitigation measures, preparation of project plans, data availability, Indian Trust issues and relevant environmental technologies. An important aspect of gaining access to federal, state, tribal, or fee lands involves education of a broad array of stakeholders, including land and mineral owners, regulators, conservationists, tribal governments, special interest groups, and numerous others that could be impacted by the development of coal bed methane. Perhaps the most crucial aspect of successfully developing CBM resources is stakeholder education. Currently, an inconsistent picture of CBM exists. There is a significant lack of understanding on the parts of nearly all stakeholders, including industry, government, special interest groups, and land owners. It is envisioned the Primer would being used by a variety of

  15. Genomic selection for methane emission

    DEFF Research Database (Denmark)

    de Haas, Yvette; Pryce, Jennie E; Wall, Eileen

    2016-01-01

    Climate change is a growing area of international concern, and it is well established that the release of greenhouse gases (GHG) is a contributing factor. Of the various GHG produced by ruminants, enteric methane (CH4 ) is the most important contributor. One mitigation strategy is to reduce methane...... emission through genetic selection. Our first attempt used beef cattle and a GWAS to identify genes associated with several CH4 traits in Angus beef cattle. The Angus population consisted of 1020 animals with phenotypes on methane production (MeP), dry matter intake (DMI), and weight (WT). Additionally......, two new methane traits: residual genetic methane (RGM) and residual phenotypic methane (RPM) were calculated by adjusting CH4 for DMI and WT. Animals were genotyped using the 800k Illumina Bovine HD Array. Estimated heritabilities were 0.30, 0.19 and 0.15 for MeP, RGM and RPM respectively...

  16. Methanization of industrial liquid effluents

    International Nuclear Information System (INIS)

    Frederic, S.; Lugardon, A.

    2007-01-01

    In a first part, this work deals with the theoretical aspects of the methanization of the industrial effluents; the associated reactional processes are detailed. The second part presents the technological criteria for choosing the methanization process in terms of the characteristics of the effluent to be treated. Some of the methanization processes are presented with their respective advantages and disadvantages. At last, is described the implementation of an industrial methanization unit. The size and the main choices are detailed: the anaerobic reactor, the control, the valorization aspects of the biogas produced. Some examples of industrial developments illustrate the different used options. (O.M.)

  17. Methane emissions from coal mining

    International Nuclear Information System (INIS)

    Boyer, C.M.; Kelafant, J.R.; Kuuskraa, V.A.; Manger, K.C.; Kruger, D.

    1990-09-01

    The report estimates global methane emissions from coal mining on a country specific basis, evaluates the technologies available to degasify coal seams and assesses the economics of recovering methane liberated during mining. 33 to 64 million tonnes were liberated in 1987 from coal mining, 75 per cent of which came from China, the USSR, Poland and the USA. Methane emissions from coal mining are likely to increase. Emission levels vary between surface and underground mines. The methane currently removed from underground mines for safety reasons could be used in a number of ways, which may be economically attractive. 55 refs., 19 figs., 24 tabs

  18. Humboldt Bay Orthoimages

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of 0.5-meter pixel resolution, four band orthoimages covering the Humboldt Bay area. An orthoimage is remotely sensed image data in which...

  19. Chesapeake Bay Tributary Strategies

    Science.gov (United States)

    Chesapeake Bay Tributary Strategies were developed by the seven watershed jurisdictions and outlined the river basin-specific implementation activities to reduce nutrient and sediment pollutant loads from point and nonpoint sources.

  20. Bathymetry in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 4x4 meter resolution bathymetric surface for Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The depth values are in meters referenced to the...

  1. Biscayne Bay Alongshore Epifauna

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Field studies to characterize the alongshore epifauna (shrimp, crabs, echinoderms, and small fishes) along the western shore of southern Biscayne Bay were started in...

  2. Hammond Bay Biological Station

    Data.gov (United States)

    Federal Laboratory Consortium — Hammond Bay Biological Station (HBBS), located near Millersburg, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). HBBS was established by...

  3. Growth of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a high-pressure membrane capsule bioreactor.

    Science.gov (United States)

    Timmers, Peer H A; Gieteling, Jarno; Widjaja-Greefkes, H C Aura; Plugge, Caroline M; Stams, Alfons J M; Lens, Piet N L; Meulepas, Roel J W

    2015-02-01

    Communities of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) grow slowly, which limits the ability to perform physiological studies. High methane partial pressure was previously successfully applied to stimulate growth, but it is not clear how different ANME subtypes and associated SRB are affected by it. Here, we report on the growth of ANME-SRB in a membrane capsule bioreactor inoculated with Eckernförde Bay sediment that combines high-pressure incubation (10.1 MPa methane) and thorough mixing (100 rpm) with complete cell retention by a 0.2-m-pore-size membrane. The results were compared to previously obtained data from an ambient-pressure (0.101 MPa methane) bioreactor inoculated with the same sediment. The rates of oxidation of labeled methane were not higher at 10.1 MPa, likely because measurements were done at ambient pressure. The subtype ANME-2a/b was abundant in both reactors, but subtype ANME-2c was enriched only at 10.1 MPa. SRB at 10.1 MPa mainly belonged to the SEEP-SRB2 and Eel-1 groups and the Desulfuromonadales and not to the typically found SEEP-SRB1 group. The increase of ANME-2a/b occurred in parallel with the increase of SEEP-SRB2, which was previously found to be associated only with ANME-2c. Our results imply that the syntrophic association is flexible and that methane pressure and sulfide concentration influence the growth of different ANME-SRB consortia. We also studied the effect of elevated methane pressure on methane production and oxidation by a mixture of methanogenic and sulfate-reducing sludge. Here, methane oxidation rates decreased and were not coupled to sulfide production, indicating trace methane oxidation during net methanogenesis and not anaerobic methane oxidation, even at a high methane partial pressure.

  4. Methane from wood

    International Nuclear Information System (INIS)

    Schulz, T. F.; Barreto, L.; Kypreos, S.; Stucki, S.

    2005-07-01

    The role of wood-based energy technologies in the Swiss energy system in the long-term is examined using the energy-system Swiss MARKAL model. The Swiss MARKAL model is a 'bottom-up' energy-systems optimization model that allows a detailed representation of energy technologies. The model has been developed as a joint effort between the Energy Economics Group (EEG) at Paul Scherrer Institute PSI) and the University of Geneva and is currently used at PSI-EEG. Using the Swiss MARKAL model, this study examines the conditions under which wood-based energy technologies could play a role in the Swiss energy system, the most attractive pathways for their use and the policy measures that could support them. Given the involvement of PSI in the ECOGAS project, especial emphasis is put on the production of bio-SNG from wood via gasification and methanation of syngas and on hydrothermal gasification of woody biomass. Of specific interest as weIl is the fraction of fuel used in passenger cars that could be produced by locally harvested wood. The report is organized as follows: Section 2 presents a brief description of the MARKAL model. Section 3 describes the results of the base case scenario, which represents a plausible, 'middle-of-the-road' development of the Swiss energy system. Section 4 discusses results illustrating the conditions under which the wood-based methanation technology could become competitive in the Swiss energy market, the role of oil and gas prices, subsidies to methanation technologies and the introduction of a competing technology, namely the wood-based Fischer-Tropsch synthesis. FinaIly, section 5 outlines some conclusions from this analysis. (author)

  5. Tetrakis(dimethoxyboryl)methane

    OpenAIRE

    Sumeng Liu; Gregory S. Girolami

    2016-01-01

    The title compound, tetrakis(dimethoxyboryl)methane (systematic name: octamethyl methanetetrayltetraboronate), C9H24B4O8 or C[B(OMe)2]4, is a useful synthetic intermediate. Crystals of this compound at 102 K conform to the orthorhombic space group Pbcn. The molecules, which reside on sites of crystallographic twofold symmetry, have idealized -4 point symmetry like most other CX4 molecules in which each X group bears two non-H substituents at the 1-position. The central C atom has a slightly d...

  6. Expansion of Phragmites australis alters methane dynamics and methanogen, methanotroph, and sulfate reducing bacteria communities in tidal marsh in Korea

    Science.gov (United States)

    Kim, J.; Lee, J.; Kim, H.; Gauhar, M.; Kang, H.

    2016-12-01

    Plant invasion is known to change substantially methane dynamics in tidal marshes. However, the exact mechanisms related to methane dynamics change due to plant invasion have not been fully understood. In Suncheon Bay, South Korea, Phragmites australis has invaded the habitat of native species, Suaeda japonica, and becomes dominant vegetation in this area. We measured methane fluxes, soil biogeochemistry, and microbial communities from both vegetation sites throughout a growing season and conducted a chronosequence analysis in order to illustrate the effect of plant invasion on methane dynamics and microbial communities. For analyzing microbial communities, we collected 1m intact soil cores and conducted functional gene-targeted real-time qPCR, T-RFLP, and PLFA. P. australis invasion significantly increased methane emission in a summer season, accompanied by greater dissolved organic carbon and soil water content. Methanogen, methanotroph, and sulfate reducing bacterial communities were gradually changed along with the invasion periods. In particular, abundances ratio of mcrA/pmoA and mcrA/dsrA had a positive correlation with methane emission, which indicates that P. australis invasion reduces methane oxidation by methanotroph, and competitive inhibition between methanogen and sulfate reducing bacteria. In conclusion, P. australis invasion on S. japonica significantly increased methane emission in tidal marsh by altering the microbial communities in a way that C decomposition would be dominated by methanogenesis.

  7. 75 FR 11837 - Chesapeake Bay Watershed Initiative

    Science.gov (United States)

    2010-03-12

    ... DEPARTMENT OF AGRICULTURE Commodity Credit Corporation Chesapeake Bay Watershed Initiative AGENCY...: Notice of availability of program funds for the Chesapeake Bay Watershed Initiative. SUMMARY: The... through the Chesapeake Bay Watershed Initiative for agricultural producers in the Chesapeake Bay watershed...

  8. Methane production and methane consumption: a review of processes underlying wetland methane fluxes.

    NARCIS (Netherlands)

    Segers, R.

    1998-01-01

    Potential rates of both methane production and methane consumption vary over three orders of magnitude and their distribution is skew. These rates are weakly correlated with ecosystem type, incubation temperature, in situ aeration, latitude, depth and distance to oxic/anoxic interface. Anaerobic

  9. Chesapeake Bay Program Grant Guidance

    Science.gov (United States)

    Grant Guidance and appendices for the Chesapeake Bay Program that describes how the U.S. Environmental Protection Agency’s (EPA) Region 3’s Chesapeake Bay Program Office (CBPO) administers grant and cooperative agreement funds.

  10. Chesapeake Bay under stress

    Science.gov (United States)

    According to extensive data obtained over its 13,000 km of shoreline, the Chesapeake Bay has been suffering a major, indeed unprecedented, reduction in submerged vegetation. Chesapeake Bay is alone in experiencing decline in submerged vegetation. Other estuary systems on the east coast of the United States are not so affected. These alarming results were obtained by the synthesis of the findings of numerous individual groups in addition to large consortium projects on the Chesapeake done over the past decade. R. J. Orth and R. A. Moore of the Virginia Institute of Marine Science pointed to the problem of the severe decline of submerged grasses on the Bay and along its tributaries. In a recent report, Orth and Moore note: “The decline, which began in the 1960's and accelerated in the 1970's, has affected all species in all areas. Many major river systems are now totally devoid of any rooted vegetation” (Science, 222, 51-53, 1983).

  11. Methane Hydrates: Chapter 8

    Science.gov (United States)

    Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

    2008-01-01

    Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be

  12. 77 FR 40032 - Methane Hydrate Advisory Committee

    Science.gov (United States)

    2012-07-06

    ... DEPARTMENT OF ENERGY Methane Hydrate Advisory Committee AGENCY: Office of Fossil Energy, Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Methane... of the Methane Hydrate Advisory Committee is to provide advice on potential applications of methane...

  13. Phytoremediation of Atmospheric Methane

    Science.gov (United States)

    2013-04-15

    greenhouse gases produced by human activity are  carbon   dioxide , methane and  nitrous oxide.  Much attention has been directed toward CO2 mitigation...surface  ocean .   Acidification  and ultimately warming due to CO2 alone must be  addressed by removing CO2 from the atmosphere and prevention of further...as a  carbon  and energy source. One soluble MMO (sMMO)  system is expressed by some methanotrophs under conditions of low copper concentration and

  14. Keys to methane conversion technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lange, J.P.; De Jong, K.P. [Shell Research, Koninklijke/Shell-Laboratorium, Amsterdam (Netherlands); Ansorge, J. [Shell Internationale Petroleum Maatschappij, The Hague (Netherlands); Tijm, P.J.A. [Shell International Gas Ltd, Shell Center, London (United Kingdom)

    1997-12-31

    Numerous process schemes have been put forward for converting methane to liquid hydrocarbon fuels. A proper selection and design of new or emerging methane conversion processes requires insight into the technical and economic issues that are critical for their viability. Three process requirements will be highlighted here, namely large plant scale, high thermal efficiency and low overall heat and momentum transfer duty. Since the overall heat and momentum transfer duty is strongly affected by the achievable yield per pass, the parameters which seem to rule the maximum yield per pass of methane conversion routes are also investigated. 15 refs.

  15. Recent advances in methane activation

    Energy Technology Data Exchange (ETDEWEB)

    Huuska, M.; Kataja, K. [VTT Chemical Technology, Espoo (Finland)

    1996-12-31

    Considerable work has been done in the research and development of methane conversion technologies. Although some promising conversion processes have been demonstrated, further advances in engineering and also in the chemistry are needed before these technologies become commercial. High-temperature processes, e.g. the oxidative coupling of methane, studied thoroughly during the last 15 years, suffer from severe theoretical yield limits and poor economics. In the long term, the most promising approaches seem to be the organometallic and, especially, the biomimetic activation of methane. (author) (22 refs.)

  16. Methane hydroxylation: a biomimetic approach

    International Nuclear Information System (INIS)

    Shilov, Aleksandr E; Shteinman, Al'bert A

    2012-01-01

    The review addresses direct methane oxidation — an important fundamental problem, which has attracted much attention of researchers in recent years. Analysis of the available results on biomimetic and bio-inspired methane oxygenation has demonstrated that assimilating of the experience of Nature on oxidation of methane and other alkanes significantly enriches the arsenal of chemistry and can radically change the character of the entire chemical production, as well as enables the solution of many material, energetic and environmental problems. The bibliography includes 310 references.

  17. Anthropogenic methane ebullition and continuous flux measurement

    Science.gov (United States)

    Alshboul, Zeyad

    2017-04-01

    Keywords: Methane, Wastewater, Effluent, Anaerobic treatment. Municipal wastewater treatment plants (WWTPs) have shown to emit significant amount of methane during treatment processes. While most of studies cover only in-plant diffusive methane flux, magnitude and sources of methane ebullition have not well assessed. Moreover, the reported results of methane emissions from WWTPs are based on low spatial and temporal resolution. Using a continuous measurement approach of methane flux rate for effluent system and secondary clarifier treatment process at one WWTP in Southwest Germany, our results show that high percentage of methane is emitted by ebullition during the anaerobic treatment (clarification pond) with high spatial and temporal variability. Our measurements revealed that no ebullition is occur at the effluent system. The observed high contribution of methane ebullition to the total in-plant methane emission, emphasizes the need for considering in-plant methane emission by ebullition as well as the spatial and temporal variability of these emissions.

  18. Global Methane Biogeochemistry

    Science.gov (United States)

    Reeburgh, W. S.

    2003-12-01

    Methane (CH4) has been studied as an atmospheric constituent for over 200 years. A 1776 letter from Alessandro Volta to Father Campi described the first experiments on flammable "air" released by shallow sediments in Lake Maggiore (Wolfe, 1996; King, 1992). The first quantitative measurements of CH4, both involving combustion and gravimetric determination of trapped oxidation products, were reported in French by Boussingault and Boussingault, 1864 and Gautier (1901), who reported CH4 concentrations of 10 ppmv and 0.28 ppmv (seashore) and 95 ppmv (Paris), respectively. The first modern measurements of atmospheric CH4 were the infrared absorption measurements of Migeotte (1948), who estimated an atmospheric concentration of 2.0 ppmv. Development of gas chromatography and the flame ionization detector in the 1950s led to observations of vertical CH4 distributions in the troposphere and stratosphere, and to establishment of time-series sampling programs in the late 1970s. Results from these sampling programs led to suggestions that the concentration of CH4, as that of CO2, was increasing in the atmosphere. The possible role of CH4 as a greenhouse gas stimulated further research on CH4 sources and sinks. Methane has also been of interest to microbiologists, but findings from microbiology have entered the larger context of the global CH4 budget only recently.Methane is the most abundant hydrocarbon in the atmosphere. It plays important roles in atmospheric chemistry and the radiative balance of the Earth. Stratospheric oxidation of CH4 provides a means of introducing water vapor above the tropopause. Methane reacts with atomic chlorine in the stratosphere, forming HCl, a reservoir species for chlorine. Some 90% of the CH4 entering the atmosphere is oxidized through reactions initiated by the OH radical. These reactions are discussed in more detail by Wofsy (1976) and Cicerone and Oremland (1988), and are important in controlling the oxidation state of the atmosphere

  19. Field Exploration of Methane Seep Near Atqasuk

    Energy Technology Data Exchange (ETDEWEB)

    Katey Walter, Dennis Witmer, Gwen Holdmann

    2008-12-31

    Methane (CH{sub 4}) in natural gas is a major energy source in the U.S., and is used extensively on Alaska's North Slope, including the oilfields in Prudhoe Bay, the community of Barrow, and the National Petroleum Reserve, Alaska (NPRA). Smaller villages, however, are dependent on imported diesel fuel for both power and heating, resulting in some of the highest energy costs in the U.S. and crippling local economies. Numerous CH{sub 4} gas seeps have been observed on wetlands near Atqasuk, Alaska (in the NPRA), and initial measurements have indicated flow rates of 3,000-5,000 ft{sup 3} day{sup -1} (60-100 kg CH{sub 4} day{sup -1}). Gas samples collected in 1996 indicated biogenic origin, although more recent sampling indicated a mixture of biogenic and thermogenic gas. In this study, we (1) quantified the amount of CH{sub 4} generated by several seeps and evaluated their potential use as an unconventional gas source for the village of Atqasuk; (2) collected gas and analyzed its composition from multiple seeps several miles apart to see if the source is the same, or if gas is being generated locally from isolated biogenic sources; and (3) assessed the potential magnitude of natural CH{sub 4} gas seeps for future use in climate change modeling.

  20. Richards Bay effluent pipeline

    CSIR Research Space (South Africa)

    Lord, DA

    1986-07-01

    Full Text Available ..................................... 26 BACKGROUND Historical The town of Richards Bay is situated on the east coast of South Africa, approximately 160 km north-east of Durban, and was named after Sir Frederick William Richards. Although the area was already known...

  1. Enteric Methane Emission from Pigs

    DEFF Research Database (Denmark)

    Jørgensen, Henry; Theil, Peter Kappel; Knudsen, Knud Erik Bach

    2011-01-01

    per kg meat produced is increased (Fernández et al. 1983; Lekule et al. 1990). The present chapter will summarise our current knowledge concerning dietary and enteric fermentation that may influence the methane (CH4) emission in pigs. Enteric fermentation is the digestive process by which.......3 % of the worlds pig population. The main number of pigs is in Asia (59.6 %) where the main pig population stay in China (47.8 % of the worlds pig population). The objective of the chapter is therefore: To obtain a general overview of the pigs’ contribution to methane emission. Where is the pigs’ enteric gas...... produced and how is it measured. The variation in methane emission and factors affecting the emission. Possibility for reducing the enteric methane emission and the consequences....

  2. Methane Liquid Level Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Technologies Group, Inc. proposes the development of a Methane Liquid-Level Sensor, (MLS) for In-Space cryogenic storage capable of continuous monitoring of...

  3. Methane LIDAR Laser Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fibertek proposes to develop laser technology intended to meet NASA's need for innovative lidar technologies for atmospheric measurements of methane. NASA and the...

  4. Biological hydrogen methanation - A review.

    Science.gov (United States)

    Lecker, Bernhard; Illi, Lukas; Lemmer, Andreas; Oechsner, Hans

    2017-12-01

    Surplus energy out of fluctuating energy sources like wind and solar energy is strongly increasing. Biological hydrogen (H 2 ) methanation (BHM) is a highly promising approach to move the type of energy from electricity to natural gas via electrolysis and the subsequent step of the Sabatier-reaction. This review provides an overview of the numerous studies concerning the topic of BHM. The technical and biological parameters regarding the research results of these studies are compared and analyzed hereafter. A holistic view on how to overcome physical limitations of the fermentation process, such as gas-liquid mass transfer or a rise of the pH value, and on the enhancement of environmental circumstances for the bacterial biomass are delivered within. With regards to ex-situ methanation, the evaluated studies show a distinct connection between methane production and the methane percentage in the off-gas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Miniature Airborne Methane Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — KalScott Engineering, and the subcontractor, Princeton University propose the development and demonstration of compact and robust methane sensor for small Unmanned...

  6. The California Baseline Methane Survey

    Science.gov (United States)

    Duren, R. M.; Thorpe, A. K.; Hopkins, F. M.; Rafiq, T.; Bue, B. D.; Prasad, K.; Mccubbin, I.; Miller, C. E.

    2017-12-01

    The California Baseline Methane Survey is the first systematic, statewide assessment of methane point source emissions. The objectives are to reduce uncertainty in the state's methane budget and to identify emission mitigation priorities for state and local agencies, utilities and facility owners. The project combines remote sensing of large areas with airborne imaging spectroscopy and spatially resolved bottom-up data sets to detect, quantify and attribute emissions from diverse sectors including agriculture, waste management, oil and gas production and the natural gas supply chain. Phase 1 of the project surveyed nearly 180,000 individual facilities and infrastructure components across California in 2016 - achieving completeness rates ranging from 20% to 100% per emission sector at < 5 meters spatial resolution. Additionally, intensive studies of key areas and sectors were performed to assess source persistence and variability at times scales ranging from minutes to months. Phase 2 of the project continues with additional data collection in Spring and Fall 2017. We describe the survey design and measurement, modeling and analysis methods. We present initial findings regarding the spatial, temporal and sectoral distribution of methane point source emissions in California and their estimated contribution to the state's total methane budget. We provide case-studies and lessons learned about key sectors including examples where super-emitters were identified and mitigated. We summarize challenges and recommendations for future methane research, inventories and mitigation guidance within and beyond California.

  7. Historical methane hydrate project review

    Science.gov (United States)

    Collett, Timothy; Bahk, Jang-Jun; Frye, Matt; Goldberg, Dave; Husebo, Jarle; Koh, Carolyn; Malone, Mitch; Shipp, Craig; Torres, Marta

    2013-01-01

    In 1995, U.S. Geological Survey made the first systematic assessment of the volume of natural gas stored in the hydrate accumulations of the United States. That study, along with numerous other studies, has shown that the amount of gas stored as methane hydrates in the world greatly exceeds the volume of known conventional gas resources. However, gas hydrates represent both a scientific and technical challenge and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of gas hydrates in nature, (2) assessing the volume of natural gas stored within various gas hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural gas hydrates, and (5) analyzing the effects of methane hydrate on drilling safety.Methane hydrates are naturally occurring crystalline substances composed of water and gas, in which a solid water-­‐lattice holds gas molecules in a cage-­‐like structure. The gas and water becomes a solid under specific temperature and pressure conditions within the Earth, called the hydrate stability zone. Other factors that control the presence of methane hydrate in nature include the source of the gas included within the hydrates, the physical and chemical controls on the migration of gas with a sedimentary basin containing methane hydrates, the availability of the water also included in the hydrate structure, and the presence of a suitable host sediment or “reservoir”. The geologic controls on the occurrence of gas hydrates have become collectively known as the “methane hydrate petroleum system”, which has become the focus of numerous hydrate research programs.Recognizing the importance of methane hydrate research and the need for a coordinated

  8. Sustainable development in the Hudson Bay/James Bay bioregion

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    An overview is presented of projects planned for the James Bay/Hudson Bay region, and the expected environmental impacts of these projects. The watershed of James Bay and Hudson Bay covers well over one third of Canada, from southern Alberta to central Ontario to Baffin Island, as well as parts of north Dakota and Minnesota in the U.S.A. Hydroelectric power developments that change the timing and rate of flow of fresh water may cause changes in the nature and duration of ice cover, habitats of marine mammals, fish and migratory birds, currents into and out of Hudson Bay/James Bay, seasonal and annual loads of sediments and nutrients to marine ecosystems, and anadromous fish populations. Hydroelectric projects are proposed for the region by Quebec, Ontario and Manitoba. In January 1992, the Canadian Arctic Resources Committee (CARC), the Environmental Committee of Sanikuluaq, and the Rawson Academy of Arctic Science will launch the Hudson Bay/James Bay Bioregion Program, an independent initiative to apply an ecosystem approach to the region. Two main objectives are to provide a comprehensive assessment of the cumulative impacts of human activities on the marine and freshwater ecosystems of the Hudson Bay/James Bay bioregion, and to foster sustainable development by examining and proposing cooperative processes for decision making among governments, developers, aboriginal peoples and other stakeholders. 1 fig

  9. Inhibition experiments on anaerobic methane oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Alperin, M.J.; Reeburgh, W.S.

    1985-10-01

    Anaerobic methane oxidation is a general process important in controlling fluxes of methane from anoxic marine sediments. The responsible organism has not been isolated, and little is known about the electron acceptors and substrates involved in the process. Laboratory evidence indicates that sulfate reducers and methanogens are able to oxidize small quantities of methane. Field evidence suggests anaerobic methane oxidation may be linked to sulfate reduction. Experiments with specific inhibitors for sulfate reduction (molybdate), methanogenesis (2-bromoethanesulfonic acid), and acetate utilization (fluoroacetate) were performed on marine sediments from the zone of methane oxidation to determine whether sulfate-reducing bacteria or methanogenic bacteria are responsible for methane oxidation. The inhibition experiment results suggest that methane oxidation in anoxic marine sediments is not directly mediated by sulfate-reducing bacteria or methanogenic bacteria. Our results are consistent with two possibilities: anaerobic methane oxidation may be mediated by an unknown organism or a consortium involving an unknown methane oxidizer and sulfate-reducing bacteria.

  10. Quantification of methane emissions from danish landfills

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Mønster, Jacob; Kjeldsen, Peter

    2013-01-01

    Whole-landfill methane emission was quantified using a tracer technique that combines controlled tracer gas release from the landfill with time-resolved concentration measurements downwind of the landfill using a mobile high-resolution analytical instrument. Methane emissions from 13 Danish...... landfills varied between 2.6 and 60.8 kg CH4 h–1. The highest methane emission was measured at the largest (in terms of disposed waste amounts) of the 13 landfills, whereas the lowest methane emissions (2.6-6.1 kgCH4 h–1) were measured at the older and smaller landfills. At two of the sites, which had gas...... collection, emission measurements showed that the gas collection systems only collected between 30-50% of the methane produced (assuming that the produced methane equalled the sum of the emitted methane and the collected methane). Significant methane emissions were observed from disposed shredder waste...

  11. Is methane a new therapeutic gas?

    Directory of Open Access Journals (Sweden)

    Liu Wenwu

    2012-09-01

    Full Text Available Abstract Background Methane is an attractive fuel. Biologically, methanogens in the colon can use carbon dioxide and hydrogen to produce methane as a by-product. It was previously considered that methane is not utilized by humans. However, in a recent study, results demonstrated that methane could exert anti-inflammatory effects in a dog small intestinal ischemia-reperfusion model. Point of view Actually, the bioactivity of methane has been investigated in gastrointestinal diseases, but the exact mechanism underlying the anti-inflammatory effects is required to be further elucidated. Methane can cross the membrane and is easy to collect due to its abundance in natural gas. Although methane is flammable, saline rich in methane can be prepared for clinical use. These seem to be good news in application of methane as a therapeutic gas. Conclusion Several problems should be resolved before its wide application in clinical practice.

  12. Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

    Energy Technology Data Exchange (ETDEWEB)

    Kirchman, David L. [Univ. of Delaware, Lewes, DE (United States)

    2012-03-29

    The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

  13. Sediment-water and Sea-Air Fluxes of Methane along a Salinity and Eutrophication Gradient in the Coastal Baltic Sea

    Science.gov (United States)

    Bruchert, V.; Bastviken, D.; Ginters, L.

    2011-12-01

    Benthic and sea-air fluxes, water column methane measurements, and rates of methanogenesis were determined in a coastal embayment of the central Baltic. The embayment, Himmerfjärden, is an elongated estuarine system of silled sub-basins with water depths up to 50 m and characterized by a pronounced eutrophication and salinity gradient, and episodic late summer/fall bottom water anoxia. Himmerfjärden sediments consist of Holocene mud, sand, and glacial clay. Benthic methane fluxes from sediments were calculated from measurements obtained in the spring, summer, and fall of 2010 and 2011 at 5 stations within the bay area. Sediment data were combined with water column measurements of methane and sea-air flux chamber measurements to establish the spatial and temporal variability of coastal methane emissions to the atmosphere. Along a depth gradient from 3 meter to 70 meter water depth, methane fluxes were between 0.12 and 0.025 mmol m-2 d-1. Bottom water oxygen concentrations had a strong effect on bottom water methane concentrations, but sea-air fluxes of methane were independent of the bottom water oxygen concentrations suggesting efficient oxidation of methane in the water column. Water depth had the strongest effect on methane flux suggesting ebullition as the dominant transport mechanism. In the inner parts of Himmerfjärden, methane concentration profiles showed a pronounced maximum in the mixed layer, which was consistently oversaturated relative to concentrations expected in equilibrium with the atmosphere. These high concentrations may be related to treated sewage discharge to the mixed layer from a local sewage treatment plant. Our combined sediment and water column data suggest that the Himmerfjärden waters are a weak source of methane to the atmosphere. Atmospheric methane fluxes are characterized by significant spatial heterogeneities that are controlled both by present-day nutrient discharge and the distribution of gas-containing Holocene sediments.

  14. Long-term monitoring of breath methane.

    Science.gov (United States)

    Polag, Daniela; Keppler, Frank

    2018-05-15

    In recent years, methane as a component of exhaled human breath has been considered as a potential bioindicator providing information on microbial activity in the intestinal tract. Several studies indicated a relationship between breath methane status and specific gastrointestinal disease. So far, almost no attention has been given to the temporal variability of breath methane production by individual persons. Thus here, for the first time, long-term monitoring was carried out measuring breath methane of three volunteers over periods between 196 and 1002days. Results were evaluated taking into consideration the health status and specific medical intervention events for each individual during the monitoring period, and included a gastroscopy procedure, a vaccination, a dietary change, and chelate therapy. As a major outcome, breath methane mixing ratios show considerable variability within a person-specific range of values. Interestingly, decreased breath methane production often coincided with gastrointestinal complaints whereas influenza infections were mostly accompanied by increased breath methane production. A gastroscopic examination as well as a change to a low-fructose diet led to a dramatic shift of methane mixing ratios from high to low methane production. In contrast, a typhus vaccination as well as single chelate injections resulted in significant short-term methane peaks. Thus, this study clearly shows that humans can change from high to low methane emitters and vice versa within relatively short time periods. In the case of low to medium methane emitters the increase observed in methane mixing ratios, likely resulting from immune reactions and inflammatory processes, might indicate non-microbial methane formation under aerobic conditions. Although detailed reaction pathways are not yet known, aerobic methane formation might be related to cellular oxidative-reductive stress reactions. However, a detailed understanding of the pathways involved in human

  15. Methane as a climate gas

    Energy Technology Data Exchange (ETDEWEB)

    Karlsdottir, S.

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Methane is a key component in the atmosphere where its concentration has increased rapidly since pre-industrial time. About 2/3 of it is caused by human activities. Changes in methane will affect the concentrations of other gases, and a model is a very important tool to study sensitivity due to changes in concentration of gases. The author used a three-dimensional global chemistry transport model to study the effect of changes in methane concentration on other trace gases. The model includes natural and anthropogenic emissions of NOx, CO, CH{sub 4} and non-methane hydrocarbons. Wet and dry deposition are also included. The chemical scheme in the model includes 49 compounds, 101 reactions, and 16 photolytic reactions. The trace gas concentrations are calculated every 30 min, using a quasi steady state approximation. Model calculations of three cases are reported and compared. Enhanced methane concentration will have strongest effect in remote regions. In polluted areas local chemistry will have remarked effect. The feedback was always positive. Average atmospheric lifetime calculated in the model was 7.6 years, which agrees with recent estimates based on observations. 8 refs.

  16. Vertical structure and horizontal variations in the cycling of methane in the sediment of Lake Onego, Russia

    Science.gov (United States)

    Thomas, Camille; Perga, Marie-Elodie; Frossard, Victor; Pasche, Natacha; Hofmann, Hilmar; Ariztegui, Daniel; Dubois, Nathalie; Belkina, Natalya; Lyautey, Emilie

    2017-04-01

    Lake Onego, the second largest lake in Europe, is a dystrophic, seasonally ice-covered lake in Karelia, Russia. Like most winter-covered lakes, its study has largely been limited to the summer period. However, it is well known that methane production is still ongoing in lake sediments during winter, potentially resulting in accumulation and major release upon thawing. Within the "Life Under The Ice" research project, our objectives were to assess winter contribution to the annual methane flux in Lake Onego, and to understand conditions and factors influencing methane cycling. During two on-ice field campaigns in March 2015 and 2016, sediment cores were retrieved at different sites of Petrozavodsk Bay, located in the north-western part of the lake. DNA and RNA were extracted from these cores to investigate the functional structure of microbial communities. Genes involved in methanogenesis, anaerobic and aerobic methane oxidations were quantified along with the concentrations and isotopic ratio of methane in the sediment pore water. Incubations, fingerprinting and sequencing of mcrA genes were also realized. Vertically, the sediment is structured in a deep anoxic zone (below 10 cm) where mcrA gene and transcript copies increased implying methanogenesis, a transitional zone (5-8 cm) hosting methanotrophic organisms (Cand. Methanoperedens) able to oxidize the diffusing methane anaerobically by coupling nitrate reduction (Haroon et al., 2013), and a shallower oxic zone where methanotrophs were detected (pmoA gene and transcripts) and where methane concentrations drop below detection limit. Sediment cores were also collected at three sites along a transect from the mouth of the river Shuya (the major inflow to the bay) to the open lake. Functional assemblage close to the river mouth had higher diversity and higher potential production rates and consumption of methane than further in the lake. However, the methane produced was almost completely consumed regardless of the

  17. Methane fermentation of regionally accrued wet biomass

    OpenAIRE

    浅野, 憲哉

    2017-01-01

    The methane fermentation of Japanese mushroom ligneous bed waste was conducted for estimate steam explosion as pretreatment. Methane yield was improved to 50-75% by pretreatment of mushroom bed with severity factor 2.1-3.2

  18. A Meteor Shower Origin for Martian Methane

    Science.gov (United States)

    Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.; Steele, A.; Treiman, A.

    2015-07-01

    We present and discuss the hypothesis that martian methane arises from a meteor shower source. Infall material produces methane by UV photolysis, generating localized plumes that occur after Mars/comet orbit interactions. This hypothesis is testable.

  19. Methane layering in bord and pillar workings.

    CSIR Research Space (South Africa)

    Creedy, DP

    1997-08-01

    Full Text Available This report reviews the state of knowledge on the occurrence, investigation, detection, monitoring, prevention and dispensation of methane layers in coal mines. Mining practice throughout the world in respect of methane layering is generally reliant...

  20. Compact Microtube Igniter for Methane Rockets

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to facilitate the Evolvable Mars Campaign (EMC) LOX/Methane Propulsion Architecture by developing a reliable, compact, low power methane igniter....

  1. A Possible Sink for Methane on Mars

    NARCIS (Netherlands)

    Nørnberg, P.; Jensen, S. J. K.; Skibsted, J.; Jakobsen, H. J.; ten Kate, I. L.; Gunnlaugsson, H. P.; Merrison, J. P.; Finster, K.; Bak, E.; Iversen, J. J.; Kondrup, J. C.

    2014-01-01

    Mechanical simulated wind activation of mineral surfaces act as a trap for Methane through formation of covalent Si-C bonds stable up to temperatures above 250 C. This mechanism is proposed as a Methane sink on Mars.

  2. BCDC Bay Trail Alignment 2009

    Data.gov (United States)

    California Natural Resource Agency — The Bay Trail provides easily accessible recreational opportunities for outdoor enthusiasts, including hikers, joggers, bicyclists and skaters. It also offers a...

  3. BCDC Bay Trail Alignment 2009

    Data.gov (United States)

    California Department of Resources — The Bay Trail provides easily accessible recreational opportunities for outdoor enthusiasts, including hikers, joggers, bicyclists and skaters. It also offers a...

  4. METHANE INCORPORATION BY PROCARYOTIC PHOTOSYNTHETICMICROORGANISMS

    Energy Technology Data Exchange (ETDEWEB)

    Norton, Charles J.; Kirk, Martha; Calvin, Melvin

    1970-08-01

    The procaryotic photosynthetic microorganisms Anacystis nidulans, Nostoc and Rhodospirillum rubrum have cell walls and membranes that are resistant to the solution of methane in their lipid components and intracellular fluids. But Anacystis nidulans, possesses a limited bioxidant system, a portion of which may be extracellularly secreted, which rapidly oxidizes methane to carbon dioxide. Small C{sup 14} activities derived from CH{sub 4} in excess of experimental error are detected in all the major biochemical fractions of Anacystis nidulans and Nostoc. This limited capacity to metabolize methane appears to be a vestigial potentiality that originated over two billion years ago in the early evolution of photosynthetic bacteria and blue-green algae.

  5. Wakasa Bay Weather Forecast Maps, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The AMSR-E Wakasa Bay Field Campaign was conducted over Wakasa Bay, Japan. The Wakasa Bay Field Campaign includes joint research observations, such as precipitation...

  6. Handbook methane potential; Handbok metanpotential

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, My (AnoxKaldnes AB (Sweden)); Schnurer, Anna (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden))

    2011-07-15

    Before using a organic material for biogas production it is essential to evaluate the methane production potential. The methane potential is one important tool possible to use during planning of new plants but also when new materials are considered for already running biogas plants. The chemical composition of different organic material varies extensively and this will have an impact on both the degradability and the methane potential. Information about the methane potential of a specific material can sometimes be found in the literature or can be calculated after a chemical/ physical or biological characterization. Here, the BMP test (Biochemical Methane Potential) is a commonly used method. Today the BMP test is a commonly used method to determine the methane potential. Many national and international research groups, consultants as well as personal at biogas plants are using this method and there is a lot of data available in the literature from such tests. In addition there are several protocols giving guidelines on how to execute a BMP-test. The BMP-test is performed in many different ways, not always under optimized conditions, and there is a lack of information on how to interpret the obtained data. This report summarizes knowledge from the literature and the experience from a Swedish referee group, consisting of persons being active performers of BMP-tests. The report does not include a standardized protocol as the procedure can be performed in different ways depending on available equipment and on the type of material to be tested. Instead the report discusses different factors of great importance for a successful test giving reliable results. The report also summarizes important information concerning the interpretation and how to present results in order to allow comparison of data from different test.

  7. Laboratory Investigations of Stationary Methane Anemometer

    Science.gov (United States)

    Kruczkowski, Janusz; Krawczyk, Jerzy; Ostrogórski, Piotr

    2017-12-01

    This paper presents a new stationary device that can perform simultaneous measurements of air flow velocity and methane concentration in a mine heading (stationary methane anemometer). The test station is designed to use the instrument to test the effect of various parameters on the air-methane stream. The air velocities and methane concentrations were fed to the measuring area via an injector and recorded. The results present numerical simulations of flow phenomena that occurred during measurement experiments.

  8. Methane emissions from MBT landfills.

    Science.gov (United States)

    Heyer, K-U; Hupe, K; Stegmann, R

    2013-09-01

    Within the scope of an investigation for the German Federal Environment Agency ("Umweltbundesamt"), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18-24 m(3)CH(4)/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH(4)/(m(2)h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD) model of the IPCC Guidelines for National Greenhouse Gas Inventories, 2006, was used to estimate the methane emissions from MBT landfills. Due to the calculation made by the authors emissions in the range of 60,000-135,000 t CO(2-eq.)/a for all German MBT landfills can be expected. This wide range shows the uncertainties when the here used procedure and the limited available data are applied

  9. 78 FR 26337 - Methane Hydrate Advisory Committee

    Science.gov (United States)

    2013-05-06

    ... DEPARTMENT OF ENERGY Methane Hydrate Advisory Committee AGENCY: Office of Fossil Energy, Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Methane.... SUPPLEMENTARY INFORMATION: Purpose of the Committee: The purpose of the Methane Hydrate Advisory Committee is to...

  10. 75 FR 9886 - Methane Hydrate Advisory Committee

    Science.gov (United States)

    2010-03-04

    ... DEPARTMENT OF ENERGY Methane Hydrate Advisory Committee AGENCY: Department of Energy, Office of Fossil Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Methane... the Committee: The purpose of the Methane Hydrate Advisory Committee is to provide advice on potential...

  11. 76 FR 59667 - Methane Hydrate Advisory Committee

    Science.gov (United States)

    2011-09-27

    ... DEPARTMENT OF ENERGY Methane Hydrate Advisory Committee AGENCY: Office of Fossil Energy, Department of Energy. ACTION: Notice of Open Meeting. SUMMARY: This notice announces a meeting of the Methane...-5600. SUPPLEMENTARY INFORMATION: Purpose of the Committee: The purpose of the Methane Hydrate Advisory...

  12. 78 FR 37536 - Methane Hydrate Advisory Committee

    Science.gov (United States)

    2013-06-21

    ... DEPARTMENT OF ENERGY Methane Hydrate Advisory Committee AGENCY: Office of Fossil Energy, Department of Energy. ACTION: Notice of open meeting. SUMMARY: This notice announces a meeting of the Methane... Committee: The purpose of the Methane Hydrate Advisory Committee is to provide advice on potential...

  13. 30 CFR 75.342 - Methane monitors.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Methane monitors. 75.342 Section 75.342 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.342 Methane monitors. (a)(1) MSHA approved methane monitors shall be installed on all face cutting machines, continuous miners, longwall face...

  14. Methane-fueled vehicles: A promising market for coalbed methane

    International Nuclear Information System (INIS)

    Deul, M.

    1993-01-01

    The most acceptable alternative fuel for motor vehicles is compressed natural gas (CNG). An important potential source of such gas is coalbed methane, much of which is now being wasted. Although there are no technological impediments to the use of CNG it has not been adequately promoted for a variety of reasons: structural, institutional and for coalbed gas, legal. The benefits of using CNG fuel are manifold: clean burning, low cost, abundant, and usable in any internal combustion engine. Even though more than 30,000 CNG vehicles are now in use in the U.S.A., they are not readily available, fueling stations are not easily accessible, and there is general apathy on the part of the public because of negligence by such agencies as the Department of Energy, the Department of Transportation and the Environmental Protection Agency. The economic benefits of using methane are significant: 100,000 cubic feet of methane is equivalent to 800 gallons of gasoline. Considering the many millions of cubic feet methane wasted from coal mines conservation and use of this resource is a worthy national goal

  15. Microbial diversity in restored wetlands of San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2013-12-09

    Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of belowground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we targeted the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profiled the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Our results show relationships among geochemical gradients, availability of electron acceptors, and microbial community composition. Our study provides the first genomic glimpse into microbial populations in natural and restored wetlands of the San Francisco Bay-Delta region and provides a valuable benchmark for future studies.

  16. Cryptic Methane Emissions from Upland Forest Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Megonigal, Patrick [Smithsonian Institution, Washington, DC (United States); Pitz, Scott [Johns Hopkins Univ., Baltimore, MD (United States); Smithsonian Institution, Washington, DC (United States)

    2016-04-19

    This exploratory research on Cryptic Methane Emissions from Upland Forest Ecosystems was motivated by evidence that upland ecosystems emit 36% as much methane to the atmosphere as global wetlands, yet we knew almost nothing about this source. The long-term objective was to refine Earth system models by quantifying methane emissions from upland forests, and elucidate the biogeochemical processes that govern upland methane emissions. The immediate objectives of the grant were to: (i) test the emerging paradigm that upland trees unexpectedly transpire methane, (ii) test the basic biogeochemical assumptions of an existing global model of upland methane emissions, and (iii) develop the suite of biogeochemical approaches that will be needed to advance research on upland methane emissions. We instrumented a temperate forest system in order to explore the processes that govern upland methane emissions. We demonstrated that methane is emitted from the stems of dominant tree species in temperate upland forests. Tree emissions occurred throughout the growing season, while soils adjacent to the trees consumed methane simultaneously, challenging the concept that forests are uniform sinks of methane. High frequency measurements revealed diurnal cycling in the rate of methane emissions, pointing to soils as the methane source and transpiration as the most likely pathway for methane transport. We propose the forests are smaller methane sinks than previously estimated due to stem emissions. Stem emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration, resolving differences between models and measurements. The methods we used can be effectively implemented in order to determine if the phenomenon is widespread.

  17. Ductile flow of methane hydrate

    Science.gov (United States)

    Durham, W.B.; Stern, L.A.; Kirby, S.H.

    2003-01-01

    Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

  18. Coal Mine Methane in Russia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    This paper discusses coal mine methane emissions (CMM) in the Russian Federation and the potential for their productive utilisation. It highlights specific opportunities for cost-effective reductions of CMM from oil and natural gas facilities, coal mines and landfills, with the aim of improving knowledge about effective policy approaches.

  19. Methane generation from waste materials

    Science.gov (United States)

    Samani, Zohrab A.; Hanson, Adrian T.; Macias-Corral, Maritza

    2010-03-23

    An organic solid waste digester for producing methane from solid waste, the digester comprising a reactor vessel for holding solid waste, a sprinkler system for distributing water, bacteria, and nutrients over and through the solid waste, and a drainage system for capturing leachate that is then recirculated through the sprinkler system.

  20. An ombrotrophic bog as a methane reservoir

    Science.gov (United States)

    Brown, Ann; Mathur, S. P.; Kushner, D. J.

    1989-09-01

    The distribution of methane in an ombrotrophic bog was examined by extracting the gas from different depths, using evacuated bottles and sampling tubes. Methane was extracted during 75 min, from 60 cm, 90 cm and 120 cm depths at 25 stations in a 24 meter-square area. The amount of methane extracted varied widely between samples, and this variation was greater within each depth than between the different depths. Approximately two and a half times as much methane was found at 90 cm and 120 cm depths as at 60 cm. The amount of methane from sites more than 60 cm below the surface can be correlated with the methane microbially produced from peat from the same site during laboratory incubations. Much less methane could be extracted from near-surface peat than from deeper levels, but laboratory incubations of peat from this level produced 10-fold more methane. Our results show that there is a considerable amount of methane trapped below 50 cm depth within an ombrotrophic bog, which we calculate in the bog studied to be 1.7 Gg. We suggest this entrapped methane reduces the hydraulic conductivity in the lower layers of the peat by blocking the soil pore spaces and preventing fluid movement; this in turn generates an elevated water table allowing the formation of a raised bog. We further suggest that if this peat is disturbed by mining or farming, the entrapped methane could be released into the atmosphere and add to the atmospheric pollution by greenhouse gases.

  1. Improved methane removal in exhaust gas from biogas upgrading process using immobilized methane-oxidizing bacteria.

    Science.gov (United States)

    Sun, Meng-Ting; Yang, Zhi-Man; Fu, Shan-Fei; Fan, Xiao-Lei; Guo, Rong-Bo

    2018-05-01

    Methane in exhaust gas from biogas upgrading process, which is a greenhouse gas, could cause global warming. The biofilter with immobilized methane-oxidizing bacteria (MOB) is a promising approach for methane removal, and the selections of inoculated MOB culture and support material are vital for the biofilter. In this work, five MOB consortia were enriched at different methane concentrations. The MOB-20 consortium enriched at the methane concentration of 20.0% (v/v) was then immobilized on sponge and two particle sizes of volcanic rock in biofilters to remove methane in exhaust gas from biogas upgrading process. Results showed that the immobilized MOB performed more admirable methane removal capacity than suspended cells. The immobilized MOB on sponge reached the highest methane removal efficiency (RE) of 35%. The rough surface, preferable hydroscopicity, appropriate pore size and particle size of support material might favor the MOB immobilization and accordingly methane removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Response of the Black Sea methane budget to massive short-term submarine inputs of methane

    DEFF Research Database (Denmark)

    Schmale, O.; Haeckel, M.; McGinnis, D. F.

    2011-01-01

    A steady state box model was developed to estimate the methane input into the Black Sea water column at various water depths. Our model results reveal a total input of methane of 4.7 Tg yr(-1). The model predicts that the input of methane is largest at water depths between 600 and 700 m (7......% of the total input), suggesting that the dissociation of methane gas hydrates at water depths equivalent to their upper stability limit may represent an important source of methane into the water column. In addition we discuss the effects of massive short-term methane inputs (e. g. through eruptions of deep......-water mud volcanoes or submarine landslides at intermediate water depths) on the water column methane distribution and the resulting methane emission to the atmosphere. Our non-steady state simulations predict that these inputs will be effectively buffered by intense microbial methane consumption...

  3. Estimation of methane emission flux at landfill surface using laser methane detector: Influence of gauge pressure.

    Science.gov (United States)

    Park, Jin-Kyu; Kang, Jong-Yun; Lee, Nam-Hoon

    2016-08-01

    The aim of this study was to investigate the possibility of measuring methane emission fluxes, using surface methane concentration and gauge pressure, by analyzing the influence of gauge pressure on the methane emission flux and the surface methane concentration, as well as the correlation between the methane emission flux and surface methane concentrations. The surface methane concentration was measured using a laser methane detector. Our results show a positive linear relationship between the surface methane concentration and the methane emission flux. Furthermore, the methane emission flux showed a positive linear relationship with the gauge pressure; this implies that when the surface methane concentration and the surface gauge pressure are measured simultaneously, the methane emission flux can be calculated using Darcy's law. A decrease in the vertical permeability was observed when the gauge pressure was increased, because reducing the vertical permeability may lead to a reduced landfill gas emission to the atmosphere, and landfill gas would be accumulated inside the landfill. Finally, this method is simple and can allow for a greater number of measurements during a relatively shorter period. Thus, it provides a better representation of the significant space and time variations in methane emission fluxes. © The Author(s) 2016.

  4. Methane clathrates in the solar system.

    Science.gov (United States)

    Mousis, Olivier; Chassefière, Eric; Holm, Nils G; Bouquet, Alexis; Waite, Jack Hunter; Geppert, Wolf Dietrich; Picaud, Sylvain; Aikawa, Yuri; Ali-Dib, Mohamad; Charlou, Jean-Luc; Rousselot, Philippe

    2015-04-01

    We review the reservoirs of methane clathrates that may exist in the different bodies of the Solar System. Methane was formed in the interstellar medium prior to having been embedded in the protosolar nebula gas phase. This molecule was subsequently trapped in clathrates that formed from crystalline water ice during the cooling of the disk and incorporated in this form into the building blocks of comets, icy bodies, and giant planets. Methane clathrates may play an important role in the evolution of planetary atmospheres. On Earth, the production of methane in clathrates is essentially biological, and these compounds are mostly found in permafrost regions or in the sediments of continental shelves. On Mars, methane would more likely derive from hydrothermal reactions with olivine-rich material. If they do exist, martian methane clathrates would be stable only at depth in the cryosphere and sporadically release some methane into the atmosphere via mechanisms that remain to be determined. In the case of Titan, most of its methane probably originates from the protosolar nebula, where it would have been trapped in the clathrates agglomerated by the satellite's building blocks. Methane clathrates are still believed to play an important role in the present state of Titan. Their presence is invoked in the satellite's subsurface as a means of replenishing its atmosphere with methane via outgassing episodes. The internal oceans of Enceladus and Europa also provide appropriate thermodynamic conditions that allow formation of methane clathrates. In turn, these clathrates might influence the composition of these liquid reservoirs. Finally, comets and Kuiper Belt Objects might have formed from the agglomeration of clathrates and pure ices in the nebula. The methane observed in comets would then result from the destabilization of clathrate layers in the nuclei concurrent with their approach to perihelion. Thermodynamic equilibrium calculations show that methane-rich clathrate

  5. 77 FR 35860 - Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2012-06-15

    ...-AA00 Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS. ACTION: Temporary... Island Bay, Erie, PA. This safety zone is intended to restrict vessels from a portion of the Presque... rulemaking entitled Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA in the Federal Register (77 FR 18739...

  6. Chesapeake Bay: Introduction to an Ecosystem.

    Science.gov (United States)

    Environmental Protection Agency, Washington, DC.

    The Chesapeake Bay is the largest estuary in the contiguous United States. The Bay and its tidal tributaries make up the Chesapeake Bay ecosystem. This document, which focuses of various aspects of this ecosystem, is divided into four major parts. The first part traces the geologic history of the Bay, describes the overall physical structure of…

  7. Photocatalytic conversion of methane to methanol

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.E.; Noceti, R.P.; D`Este, J.R. [Pittsburgh Energy Technology Center, PA (United States)

    1995-12-31

    A long-term goal of our research group is the exploration of novel pathways for the direct oxidation of methane to liquid fuels, chemicals, and intermediates. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol is attractive. The products of reaction, methanol and hydrogen, are both commercially desirable, methanol being used as is or converted to a variety of other chemicals, and the hydrogen could be utilized in petroleum and/or chemical manufacturing. Methane is produced as a by-product of coal gasification. Depending upon reactor design and operating conditions, up to 18% of total gasifier product may be methane. In addition, there are vast proven reserves of geologic methane in the world. Unfortunately, a large fraction of these reserves are in regions where there is little local demand for methane and it is not economically feasible to transport it to a market. There is a global research effort under way in academia, industry, and government to find methods to convert methane to useful, more readily transportable and storable materials. Methanol, the initial product of methane oxidation, is a desirable product of conversion because it retains much of the original energy of the methane while satisfying transportation and storage requirements. Investigation of direct conversion of methane to transportation fuels has been an ongoing effort at PETC for over 10 years. One of the current areas of research is the conversion of methane to methanol, under mild conditions, using light, water, and a semiconductor photocatalyst. The use of three relatively abundant and inexpensive reactants, light, water, and methane, to produce methanol, is attractive. Research in the laboratory is directed toward applying the techniques developed for the photocatalytic splitting of the water and the photochemical conversion of methane.

  8. USGS Tampa Bay Pilot Study

    Science.gov (United States)

    Yates, K.K.; Cronin, T. M.; Crane, M.; Hansen, M.; Nayeghandi, A.; Swarzenski, P.; Edgar, T.; Brooks, G.R.; Suthard, B.; Hine, A.; Locker, S.; Willard, D.A.; Hastings, D.; Flower, B.; Hollander, D.; Larson, R.A.; Smith, K.

    2007-01-01

    Many of the nation's estuaries have been environmentally stressed since the turn of the 20th century and will continue to be impacted in the future. Tampa Bay, one the Gulf of Mexico's largest estuaries, exemplifies the threats that our estuaries face (EPA Report 2001, Tampa Bay Estuary Program-Comprehensive Conservation and Management Plan (TBEP-CCMP)). More than 2 million people live in the Tampa Bay watershed, and the population constitutes to grow. Demand for freshwater resources, conversion of undeveloped areas to resident and industrial uses, increases in storm-water runoff, and increased air pollution from urban and industrial sources are some of the known human activities that impact Tampa Bay. Beginning on 2001, additional anthropogenic modifications began in Tampa Bat including construction of an underwater gas pipeline and a desalinization plant, expansion of existing ports, and increased freshwater withdrawal from three major tributaries to the bay. In January of 2001, the Tampa Bay Estuary Program (TBEP) and its partners identifies a critical need for participation from the U.S. Geological Survey (USGS) in providing multidisciplinary expertise and a regional-scale, integrated science approach to address complex scientific research issue and critical scientific information gaps that are necessary for continued restoration and preservation of Tampa Bay. Tampa Bay stakeholders identified several critical science gaps for which USGS expertise was needed (Yates et al. 2001). These critical science gaps fall under four topical categories (or system components): 1) water and sediment quality, 2) hydrodynamics, 3) geology and geomorphology, and 4) ecosystem structure and function. Scientists and resource managers participating in Tampa Bay studies recognize that it is no longer sufficient to simply examine each of these estuarine system components individually, Rather, the interrelation among system components must be understood to develop conceptual and

  9. Linking seasonal surface water dynamics with methane emissions and export from small, forested wetlands

    Science.gov (United States)

    Hondula, K. L.; Palmer, M.

    2017-12-01

    One of the biggest uncertainties about global methane sources and sinks is attributed to uncertainties regarding wetland area and its dynamics. This is exacerbated by confusion over the role of small, shallow water bodies like Delmarva bay wetlands that could be categorized as both wetlands and ponds. These small inland water bodies are often poorly quantified due to their size, closed forest canopies, and inter- and intra-annual variability in surface water extent. We are studying wetland-rich areas on the Delmarva Peninsula in the U.S. mid-Atlantic to address this uncertainty at the scale of individual wetland ecosystems (chamber measurements spanning from wetland center to upland, in order to quantify the areal extent of the methane emissions source area throughout seasonal changes in surface water inundation (water level 0 to > 1m depth). We estimated the size and temporal variability of the methane emissions source area by combining these measurements with daily estimates of the extent of surface water inundation derived from water level monitoring and a high-resolution digital elevation model. This knowledge is critical for informing land use decisions (e.g. restoring wetlands specifically for climate mitigation), the jurisdiction of environmental policies in the US, and for resolving major outstanding discrepancies in our understanding of the global methane budget.

  10. Deep-ocean field test of methane hydrate formation from a remotely operated vehicle

    Science.gov (United States)

    Brewer, Peter G.; Orr, Franklin M., Jr.; Friederich, Gernot; Kvenvolden, Keith A.; Orange, Daniel L.; McFarlane, James; Kirkwood, William

    1997-05-01

    We have observed the process of formation of clathrate hydrates of methane in experiments conducted on the remotely operated vehicle (ROV) Ventana in the deep waters of Monterey Bay. A tank of methane gas, acrylic tubes containing seawater, and seawater plus various types of sediment were carried down on Ventana to a depth of 910 m where methane gas was injected at the base of the acrylic tubes by bubble stream. Prior calculations had shown that the local hydrographic conditions gave an upper limit of 525 m for the P-T boundary defining methane hydrate formation or dissociation at this site, and thus our experiment took place well within the stability range for this reaction to occur. Hydrate formation in free seawater occurred within minutes as a buoyant mass of translucent hydrate formed at the gas-water interface. In a coarse sand matrix the filling of the pore spaces with hydrate turned the sand column into a solidified block, which gas pressure soon lifted and ruptured. In a fine-grained black mud the gas flow carved out flow channels, the walls of which became coated and then filled with hydrate in larger discrete masses. Our experiment shows that hydrate formation is rapid in natural seawater, that sediment type strongly influences the patterns of hydrate formation, and that the use of ROV technologies permits the synthesis of large amounts of hydrate material in natural systems under a variety of conditions so that fundamental research on the stability and growth of these substances is possible.

  11. The Methane Hydrate Reservoir System

    Science.gov (United States)

    Flemings, P. B.; Liu, X.

    2007-12-01

    We use multi phase flow modeling and field examples (Hydrate Ridge, offshore Oregon and Blake Ridge, offshore North Carolina) to demonstrate that the methane hydrate reservoir system links traditional and non- traditional hydrocarbon system components: free gas flow is a fundamental control on this system. As in a traditional hydrocarbon reservoir, gas migrates into the hydrate reservoir as a separate phase (secondary migration) where it is trapped in a gas column beneath the base of the hydrate layer. With sufficient gas supply, buoyancy forces exceed either the capillary entry pressure of the cap rock or the fracture strength of the cap rock, and gas leaks into the hydrate stability zone, or cap rock. When gas enters the hydrate stability zone and forms hydrate, it becomes a very non traditional reservoir. Free gas forms hydrate, depletes water, and elevates salinity until pore water is too saline for further hydrate formation: salinity and hydrate concentration increase upwards from the base of the regional hydrate stability zone (RHSZ) to the seafloor and the base of the hydrate stability zone has significant topography. Gas chimneys couple the free gas zone to the seafloor through high salinity conduits that are maintained at the three-phase boundary by gas flow. As a result, significant amounts of gaseous methane can bypass the RHSZ, which implies a significantly smaller hydrate reservoir than previously envisioned. Hydrate within gas chimneys lie at the three-phase boundary and thus small increases in temperature or decreases in pressure can immediately transport methane into the ocean. This type of hydrate deposit may be the most economical for producing energy because it has very high methane concentrations (Sh > 70%) located near the seafloor, which lie on the three-phase boundary.

  12. Methane emissions from coal mining

    International Nuclear Information System (INIS)

    Williams, A.; Mitchell, C.

    1993-01-01

    This paper outlines some of the problems associated with the prediction of levels of methane emission from underground and surface coal mines. Current knowledge of coal mining emissions sources is outlined. On the basis of this information the methodology proposed by the IPCC/OECD Programme on National Inventories is critically examined and alternatives considered. Finally, the technical options for emissions control are examined together with their feasibility. 8 refs., 6 figs., 2 tabs

  13. FL BAY SPECTROUT-DIET

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile spotted seatrout and other sportfish are being monitored annually over a 6-mo period in Florida Bay to assess their abundance over time relative to...

  14. Missisquoi Bay Phosphorus Model Addendum

    Science.gov (United States)

    This technical memorandum provides results of an extended load reduction simulation. The memorandum serves as an addendum to the main Missisquoi Bay Phosphorus Mass Balance Model report prepared for the Lake Champlain Basin Program by LimnoTech in 2012

  15. Lavaca Bay 1985-1987

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Samples were collected from October 15, 1985 through June 12, 1987 in emergent marsh and non-vegetated habitats throughout the Lavaca Bay system to characterize...

  16. Methane generated from graphite--tritium interaction

    International Nuclear Information System (INIS)

    Coffin, D.O.; Walthers, C.R.

    1979-01-01

    When hydrogen isotopes are separated by cryogenic distillation, as little as 1 ppM of methane will eventually plug the still as frost accumulates on the column packings. Elemental carbon exposed to tritium generates methane spontaneously, and yet some dry transfer pumps, otherwise compatible with tritium, convey the gas with graphite rotors. This study was to determine the methane production rate for graphite in tritium. A pump manufacturer supplied graphite samples that we exposed to tritium gas at 0.8 atm. After 137 days we measured a methane synthesis rate of 6 ng/h per cm 2 of graphite exposed. At this rate methane might grow to a concentration of 0.01 ppM when pure tritium is transferred once through a typical graphite--rotor transfer pump. Such a low methane level will not cause column blockage, even if the cryogenic still is operated continuously for many years

  17. Evaluation of methane emissions from Taiwanese paddies

    International Nuclear Information System (INIS)

    Liu, C.-W.; Wu, C.-Y.

    2004-01-01

    The main greenhouse gases are carbon dioxide, methane and nitrous oxide. Methane is the most important because the warming effect of methane is 21 times greater than that of carbon dioxide. Methane emitted from rice paddy fields is a major source of atmospheric methane. In this work, a methane emission model (MEM), which integrates climate change, plant growth and degradation of soil organic matter, was applied to estimate the emission of methane from rice paddy fields in Taiwan. The estimated results indicate that much methane is emitted during the effective tillering and booting stages in the first crop season and during the transplanting stage in the second crop season in a year. Sensitivity analysis reveals that the temperature is the most important parameter that governs the methane emission rate. The order of the strengths of the effects of the other parameters is soil pH, soil water depth (SWD) and soil organic matter content. The masses of methane emitted from rice paddy fields of Taiwan in the first and second crop seasons are 28,507 and 350,231 tons, respectively. The amount of methane emitted during the second crop season is 12.5 times higher than that emitted in the first crop season. With a 12% reduction in planted area during the second crop season, methane emission could be reduced by 21%. In addition, removal of rice straw left from the first crop season and increasing the depth of flooding to 25 cm are also strategies that could help reduce annual emission by up to 18%

  18. Ebullitive methane emissions from oxygenated wetland streams

    Science.gov (United States)

    Crawford, John T.; Stanley, Emily H.; Spawn, Seth A.; Finlay, Jacques C.; Striegl, Robert G.

    2014-01-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr−1; over 6400 km2) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle.

  19. Ebullitive methane emissions from oxygenated wetland streams.

    Science.gov (United States)

    Crawford, John T; Stanley, Emily H; Spawn, Seth A; Finlay, Jacques C; Loken, Luke C; Striegl, Robert G

    2014-11-01

    Stream and river carbon dioxide emissions are an important component of the global carbon cycle. Methane emissions from streams could also contribute to regional or global greenhouse gas cycling, but there are relatively few data regarding stream and river methane emissions. Furthermore, the available data do not typically include the ebullitive (bubble-mediated) pathway, instead focusing on emission of dissolved methane by diffusion or convection. Here, we show the importance of ebullitive methane emissions from small streams in the regional greenhouse gas balance of a lake and wetland-dominated landscape in temperate North America and identify the origin of the methane emitted from these well-oxygenated streams. Stream methane flux densities from this landscape tended to exceed those of nearby wetland diffusive fluxes as well as average global wetland ebullitive fluxes. Total stream ebullitive methane flux at the regional scale (103 Mg C yr(-1) ; over 6400 km(2) ) was of the same magnitude as diffusive methane flux previously documented at the same scale. Organic-rich stream sediments had the highest rates of bubble release and higher enrichment of methane in bubbles, but glacial sand sediments also exhibited high bubble emissions relative to other studied environments. Our results from a database of groundwater chemistry support the hypothesis that methane in bubbles is produced in anoxic near-stream sediment porewaters, and not in deeper, oxygenated groundwaters. Methane interacts with other key elemental cycles such as nitrogen, oxygen, and sulfur, which has implications for ecosystem changes such as drought and increased nutrient loading. Our results support the contention that streams, particularly those draining wetland landscapes of the northern hemisphere, are an important component of the global methane cycle. © 2014 John Wiley & Sons Ltd.

  20. International Methane Partnership Fighting Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    Due to the growth of international attention on the problem of climate change combined with the attractiveness of methane mitigation technologies, the capture and use of methane in agriculture, coal mines, landfills, and the oil and gas sector has increasingly become popular over the past few years. Highlighting this, several countries hosted the international 'Methane to Market' Partnership Conference and Exposition in October 2007 in Beijing, China.

  1. MERLIN: a space-based methane monitor

    Science.gov (United States)

    Stephan, C.; Alpers, M.; Millet, B.; Ehret, G.; Flamant, P.; Deniel, C.

    2011-10-01

    Methane is a powerful greenhouse gas. The radiative forcing caused by methane contributes significantly to the warming of the atmosphere. To better understand the complex global Methane Cycle, it is necessary to apply space-based measurements techniques in order to obtain global coverage at high precision The Methane Remote Sensing Lidar Mission (MERLIN) is a joint French-German cooperation on a micro satellite mission for space-based measurement of spatial and temporal gradients of atmospheric methane columns on a global scale. MERLIN will be the first Integrated Path Differential Absorption LIDAR for methane monitoring from space. In contrast to passive methane missions, the LIDAR instrument allows to retrieve methane fluxes at all-latitudes, allseasons and during night as it is not relying on sunlight. First scientific studies show a substantial reduction of the prior methane flux uncertainties in key observational regions when using synthetic MERLIN observations in the flux inversion experiments. Furthermore, MERLIN observations can help to quantify and verify in scientific credible way national emission reduction scenarios as formulated in the Kyoto protocol. This paper reports on the present status of MERLIN and gives an overview on the joint mission concept with the German LIDAR on the French satellite platform MYRIADE.

  2. Methane emission during municipal wastewater treatment.

    Science.gov (United States)

    Daelman, Matthijs R J; van Voorthuizen, Ellen M; van Dongen, Udo G J M; Volcke, Eveline I P; van Loosdrecht, Mark C M

    2012-07-01

    Municipal wastewater treatment plants emit methane. Since methane is a potent greenhouse gas that contributes to climate change, the abatement of the emission is necessary to achieve a more sustainable urban water management. This requires thorough knowledge of the amount of methane that is emitted from a plant, but also of the possible sources and sinks of methane on the plant. In this study, the methane emission from a full-scale municipal wastewater facility with sludge digestion was evaluated during one year. At this plant the contribution of methane emissions to the greenhouse gas footprint were slightly higher than the CO₂ emissions related to direct and indirect fossil fuel consumption for energy requirements. By setting up mass balances over the different unit processes, it could be established that three quarters of the total methane emission originated from the anaerobic digestion of primary and secondary sludge. This amount exceeded the carbon dioxide emission that was avoided by utilizing the biogas. About 80% of the methane entering the activated sludge reactor was biologically oxidized. This knowledge led to the identification of possible measures for the abatement of the methane emission. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Atmospheric methane removal by methane-oxidizing bacteria immobilized on porous building materials

    NARCIS (Netherlands)

    Ganendra, G; De Muynck, W; Ho, A.; Hoefman, S.; De Vos, P.; Boeckx, P.; Boon, N.

    2014-01-01

    Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (similar to 20 % (v/v)) and low (similar to 100 ppmv) methane

  4. Quantification of the methane concentration using anaerobic oxidation of methane coupled to extracellular electron transfer

    Science.gov (United States)

    A biofilm anode acclimated with acetate, acetate+methane, and methane growth media for over three years produced a steady current density of 1.6-2.3 mA/m^2 in a microbial electrochemical cell (MxC) fed with methane as the sole electron donor. Geobacter was the dominant genus for...

  5. CO2 Exchange in a Methane Hydrate Reservoir: Ignik Sikumi #1 Alaska Field Trial Operations and Summary Results

    Science.gov (United States)

    Hester, K. C.; Farrell, H.; Howard, J. J.; Martin, K.; Raterman, K.; Schoderbek, D.; Smith, B.; Silpngarmlert, S.

    2012-12-01

    In the winter of 2012, a CO2 exchange field trial was performed at Prudhoe Bay, Alaska. The goal was to demonstrate the feasibility of CO2 hydrate exchange technology, developed in the laboratory, on a natural methane hydrate-bearing reservoir. This included verifying the chemical exchange of CO2 with methane in addition to maintaining injectivity. Drilled in 2011, the Ignik Sikumi #1 well was perforated in February 2012. The pilot was designed as a 'huff and puff' style test where a single well is used first for injection then followed with production. The target for the test was a 10 m sand zone estimated to contain 70-80% hydrate saturation. For 13 days, over 5600 m3 of a CO2 mixture (77mol% N2, 23 mol% CO2) were injected in the hydrate-bearing interval. Injectivity was maintained over this period. Following injection, flow back commenced over a 30 day period. The production started by maintaining a bottom hole pressure above the dissociation pressure above methane hydrate. At later times, the bottom hole pressure was lowered causing both pore space fluids to be produced along with dissociation of non-exchanged original methane hydrate. In total, over 23,700 m3 of methane was produced over the production period.

  6. METHANE HYDRATE PRODUCTION FROM ALASKAN PERMAFROST

    Energy Technology Data Exchange (ETDEWEB)

    Donn McGuire; Steve Runyon; Richard Sigal; Bill Liddell; Thomas Williams; George Moridis

    2005-02-01

    Natural-gas hydrates have been encountered beneath the permafrost and considered a nuisance by the oil and gas industry for years. Engineers working in Russia, Canada and the USA have documented numerous drilling problems, including kicks and uncontrolled gas releases, in arctic regions. Information has been generated in laboratory studies pertaining to the extent, volume, chemistry and phase behavior of gas hydrates. Scientists studying hydrate potential agree that the potential is great--on the North Slope of Alaska alone, it has been estimated at 590 TCF. However, little information has been obtained on physical samples taken from actual rock containing hydrates. This gas-hydrate project is in the final stages of a cost-shared partnership between Maurer Technology, Noble Corporation, Anadarko Petroleum, and the U.S. Department of Energy's Methane Hydrate R&D program. The purpose of the project is to build on previous and ongoing R&D in the area of onshore hydrate deposition to identify, quantify and predict production potential for hydrates located on the North Slope of Alaska. Hot Ice No. 1 was planned to test the Ugnu and West Sak sequences for gas hydrates and a concomitant free gas accumulation on Anadarko's 100% working interest acreage in section 30 of Township 9N, Range 8E of the Harrison Bay quadrangle of the North Slope of Alaska. The Ugnu and West Sak intervals are favorably positioned in the hydrate-stability zone over an area extending from Anadarko's acreage westward to the vicinity of the aforementioned gas-hydrate occurrences. This suggests that a large, north-to-south trending gas-hydrate accumulation may exist in that area. The presence of gas shows in the Ugnu and West Sak reservoirs in wells situated eastward and down dip of the Hot Ice location indicate that a free-gas accumulation may be trapped by gas hydrates. The Hot Ice No. 1 well was designed to core from the surface to the base of the West Sak interval using the

  7. Isotopic analysis of atmospheric methane and of source-level methane

    International Nuclear Information System (INIS)

    Boesinger, R.

    1990-01-01

    The dissertation deals with the analysis of isotopic composition of methane near the source of emission and in the atmosphere. A method for concentration and oxidation of atmospheric methane and of methane at source level is described. The dissertation discusses in particular the formation and the degradation of methane, analysis of atmospheric and source-level methane samples via the 85 Kr-activities and measurement of the concentrations of 14 C, and the release of 14 CH 4 from the PWR reactors at Biblis and Philippsburg, which is determined by the two-tracer method (with 222 Rn as a trace substance). (HK) [de

  8. Modeling of methane bubbles released from large sea-floor area: Condition required for methane emission to the atmosphere

    OpenAIRE

    Yamamoto, A.; Yamanaka, Y.; Tajika, E.

    2009-01-01

    Massive methane release from sea-floor sediments due to decomposition of methane hydrate, and thermal decomposition of organic matter by volcanic outgassing, is a potential contributor to global warming. However, the degree of global warming has not been estimated due to uncertainty over the proportion of methane flux from the sea-floor to reach the atmosphere. Massive methane release from a large sea-floor area would result in methane-saturated seawater, thus some methane would reach the atm...

  9. Methanization takes countryside by storm

    International Nuclear Information System (INIS)

    Du Guerny, St.

    2011-01-01

    A new plant is operating in Brittany: it transforms cattle effluents and slaughterhouse wastes into electric power through natural fermentation. Thus, every year, 75.000 tons of organic wastes will produce methane and 1.5 MW. Other projects exist in the same region. One faced the opposition of the population. Therefore, the idea is now to develop smaller projects. France is very late compared to Germany and the Netherlands. The Grenelle de l'Environnement seems to have boosted these projects, notably due to the increase of the electricity purchase price proposed by EDF. Another issue is discussed: the development of this industrial sector in France

  10. Light-Dependent Aerobic Methane Oxidation Reduces Methane Emissions from Seasonally Stratified Lakes.

    Directory of Open Access Journals (Sweden)

    Kirsten Oswald

    Full Text Available Lakes are a natural source of methane to the atmosphere and contribute significantly to total emissions compared to the oceans. Controls on methane emissions from lake surfaces, particularly biotic processes within anoxic hypolimnia, are only partially understood. Here we investigated biological methane oxidation in the water column of the seasonally stratified Lake Rotsee. A zone of methane oxidation extending from the oxic/anoxic interface into anoxic waters was identified by chemical profiling of oxygen, methane and δ13C of methane. Incubation experiments with 13C-methane yielded highest oxidation rates within the oxycline, and comparable rates were measured in anoxic waters. Despite predominantly anoxic conditions within the zone of methane oxidation, known groups of anaerobic methanotrophic archaea were conspicuously absent. Instead, aerobic gammaproteobacterial methanotrophs were identified as the active methane oxidizers. In addition, continuous oxidation and maximum rates always occurred under light conditions. These findings, along with the detection of chlorophyll a, suggest that aerobic methane oxidation is tightly coupled to light-dependent photosynthetic oxygen production both at the oxycline and in the anoxic bottom layer. It is likely that this interaction between oxygenic phototrophs and aerobic methanotrophs represents a widespread mechanism by which methane is oxidized in lake water, thus diminishing its release into the atmosphere.

  11. Light-Dependent Aerobic Methane Oxidation Reduces Methane Emissions from Seasonally Stratified Lakes

    Science.gov (United States)

    Oswald, Kirsten; Milucka, Jana; Brand, Andreas; Littmann, Sten; Wehrli, Bernhard; Kuypers, Marcel M. M.; Schubert, Carsten J.

    2015-01-01

    Lakes are a natural source of methane to the atmosphere and contribute significantly to total emissions compared to the oceans. Controls on methane emissions from lake surfaces, particularly biotic processes within anoxic hypolimnia, are only partially understood. Here we investigated biological methane oxidation in the water column of the seasonally stratified Lake Rotsee. A zone of methane oxidation extending from the oxic/anoxic interface into anoxic waters was identified by chemical profiling of oxygen, methane and δ13C of methane. Incubation experiments with 13C-methane yielded highest oxidation rates within the oxycline, and comparable rates were measured in anoxic waters. Despite predominantly anoxic conditions within the zone of methane oxidation, known groups of anaerobic methanotrophic archaea were conspicuously absent. Instead, aerobic gammaproteobacterial methanotrophs were identified as the active methane oxidizers. In addition, continuous oxidation and maximum rates always occurred under light conditions. These findings, along with the detection of chlorophyll a, suggest that aerobic methane oxidation is tightly coupled to light-dependent photosynthetic oxygen production both at the oxycline and in the anoxic bottom layer. It is likely that this interaction between oxygenic phototrophs and aerobic methanotrophs represents a widespread mechanism by which methane is oxidized in lake water, thus diminishing its release into the atmosphere. PMID:26193458

  12. Microbial diversity and carbon cycling in San Francisco Bay wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

    2014-03-21

    Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangered species and provide an effective carbon storage solution, reversing land subsidence caused by a century of industrial and agricultural development. However, the benefits of carbon sequestration may be negated by increased methane production in newly constructed wetlands, making these wetlands net greenhouse gas (GHG) sources to the atmosphere. We investigated the effects of wetland restoration on below-ground microbial communities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species.

  13. 46 CFR 154.703 - Methane (LNG).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Methane (LNG). 154.703 Section 154.703 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Pressure and Temperature Control § 154.703 Methane (LN...

  14. Mechanistic insights into heterogeneous methane activation

    International Nuclear Information System (INIS)

    Latimer, Allegra A.; Aljama, Hassan; Kakekhani, Arvin; Yoo, Jong Suk; Kulkarni, Ambarish

    2017-01-01

    While natural gas is an abundant chemical fuel, its low volumetric energy density has prompted a search for catalysts able to transform methane into more useful chemicals. This search has often been aided through the use of transition state (TS) scaling relationships, which estimate methane activation TS energies as a linear function of a more easily calculated descriptor, such as final state energy, thus avoiding tedious TS energy calculations. It has been shown that methane can be activated via a radical or surface-stabilized pathway, both of which possess a unique TS scaling relationship. Herein, we present a simple model to aid in the prediction of methane activation barriers on heterogeneous catalysts. Analogous to the universal radical TS scaling relationship introduced in a previous publication, we show that a universal TS scaling relationship that transcends catalysts classes also seems to exist for surface-stabilized methane activation if the relevant final state energy is used. We demonstrate that this scaling relationship holds for several reducible and irreducible oxides, promoted metals, and sulfides. By combining the universal scaling relationships for both radical and surface-stabilized methane activation pathways, we show that catalyst reactivity must be considered in addition to catalyst geometry to obtain an accurate estimation for the TS energy. Here, this model can yield fast and accurate predictions of methane activation barriers on a wide range of catalysts, thus accelerating the discovery of more active catalysts for methane conversion.

  15. Reducing methane emissions from ruminant animals

    Energy Technology Data Exchange (ETDEWEB)

    Mathison, G.W.; Okine, E.K.; McAllister, T.A.; Dong, Y.; Galbraith, J.; Dmytruk, O.I.N. [University of Alberta, Edmonton, AB (Canada). Dept. of Agriculture, Food and Nutrition Science

    1998-09-01

    In 1992 it was estimated that 30 x 10{sup 12}g more methane was emitted into the atmosphere than was removed, with animals being considered the largest single anthropogenic source. Ruminants produce 97% of the methane generated in enteric fermentation by animals. Estimates for methane emissions from animal wastes vary between 6 and 31% of that produced directly by the animal, with the most likely value being between 5 and 10% globally. Methane inhibitors can reduce methane emissions to zero in the short term but due to microbial adaptation the effects of these compounds are quickly neutralized and feed intake is often depressed. Methane emissions per unit of feed consumed from sheep and cattle fed hay diets appear to be quite similar but differences between other ruminants have been measured. The most practical way of influencing methane emissions per unit product is to increase productivity level since the proportion of feed energy required to just maintain the animal will be reduced, methane production falls with increased intake level, and the animal may go to market sooner. The most promising avenues for future research for reducing methanogenesis are the development of new products for reducing protozoal numbers in the rumen and the use of bacterocins or other compounds which specifically target methanogenic bacteria.

  16. Methane storage in porous activated carbons

    NARCIS (Netherlands)

    András Perl; prof. dr. Wim van Gemert

    2014-01-01

    Locally produced methane, - either as biomethane or power-to-gas product, has to be stored to provide a reliable gas source for the fluctuating demand of any local gas distribution network. Additionally, methane is a prominent transportation fuel but its suitability for vehicular application depends

  17. Methane emission from wetland rice fields

    NARCIS (Netherlands)

    Denier van der Gon, H.A.C.

    1996-01-01


    Methane (CH 4 ) is an important greenhouse gas and plays a key role in tropospheric and stratospheric chemistry. Wetland rice fields are an important source of methane, accounting for approximately 20% of the global anthropogenic

  18. Raman Spectroscopic Studies of Methane Gas Hydrates

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.

    2009-01-01

    A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory.......A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory....

  19. Methane from the East Siberian Arctic shelf

    DEFF Research Database (Denmark)

    Petrenko...[], Vasilii V.; Etheridge, David M.

    2010-01-01

    In their Report “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf” (5 March, p. 1246), N. Shakhova et al. write that methane (CH4) release resulting from thawing Arctic permafrost “is a likely positive feedback to climate warming.” They add...

  20. Small Molecule Catalysts for Harvesting Methane Gas

    Energy Technology Data Exchange (ETDEWEB)

    Baker, S. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ceron-Hernandez, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oakdale, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lau, E. Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-06

    As the average temperature of the earth increases the impact of these changes are becoming apparent. One of the most dramatic changes to the environment is the melting of arctic permafrost. The disappearance of the permafrost has resulted in release of streams of methane that was trapped in remote areas as gas hydrates in ice. Additionally, the use of fracking has also increased emission of methane. Currently, the methane is either lost to the atmosphere or flared. If these streams of methane could be brought to market, this would be an abundant source of revenue. A cheap conversion of gaseous methane to a more convenient form for transport would be necessary to economical. Conversion of methane is a difficult reaction since the C-H bond is very stable (104 kcal/mole). At the industrial scale, the Fischer-Tropsch reaction can be used to convert gaseous methane to liquid methanol but is this method is impractical for these streams that have low pressures and are located in remote areas. Additionally, the Fischer-Tropsch reaction results in over oxidation of the methane leading to many products that would need to be separated.

  1. Pentagonal dodecahedron methane hydrate cage and methanol ...

    Indian Academy of Sciences (India)

    Abstract. Density functional theory based studies have been performed to elucidate the role of methanol as an methane hydrate inhibitor. A methane hydrate pentagonal dodecahedron cage's geometry optimization, natural bond orbital (NBO) analysis, Mullikan charge determination, electrostatic potential evaluation and ...

  2. Towards Understanding Methane Emissions from Abandoned Wells

    Science.gov (United States)

    Reconciliation of large-scale top-down methane measurements and bottom-up inventories requires complete accounting of source types. Methane emissions from abandoned oil and gas wells is an area of uncertainty. This presentation reviews progress to characterize the potential inv...

  3. Abiotic production of methane in terrestrial planets.

    Science.gov (United States)

    Guzmán-Marmolejo, Andrés; Segura, Antígona; Escobar-Briones, Elva

    2013-06-01

    On Earth, methane is produced mainly by life, and it has been proposed that, under certain conditions, methane detected in an exoplanetary spectrum may be considered a biosignature. Here, we estimate how much methane may be produced in hydrothermal vent systems by serpentinization, its main geological source, using the kinetic properties of the main reactions involved in methane production by serpentinization. Hydrogen production by serpentinization was calculated as a function of the available FeO in the crust, given the current spreading rates. Carbon dioxide is the limiting reactant for methane formation because it is highly depleted in aqueous form in hydrothermal vent systems. We estimated maximum CH4 surface fluxes of 6.8×10(8) and 1.3×10(9) molecules cm(-2) s(-1) for rocky planets with 1 and 5 M⊕, respectively. Using a 1-D photochemical model, we simulated atmospheres with volume mixing ratios of 0.03 and 0.1 CO2 to calculate atmospheric methane concentrations for the maximum production of this compound by serpentinization. The resulting abundances were 2.5 and 2.1 ppmv for 1 M⊕ planets and 4.1 and 3.7 ppmv for 5 M⊕ planets. Therefore, low atmospheric concentrations of methane may be produced by serpentinization. For habitable planets around Sun-like stars with N2-CO2 atmospheres, methane concentrations larger than 10 ppmv may indicate the presence of life.

  4. The operational methane retrieval algorithm for TROPOMI

    NARCIS (Netherlands)

    Hu, Haili; Hasekamp, Otto; Butz, Andre; Galli, Andre; Landgraf, Jochen; de Brugh, Joost Aan; Borsdorff, Tobias; Scheepmaker, Remco; Aben, Ilse

    2016-01-01

    This work presents the operational methane retrieval algorithm for the Sentinel 5 Precursor (S5P) satellite and its performance tested on realistic ensembles of simulated measurements. The target product is the column-averaged dry air volume mixing ratio of methane (XCH4), which will be retrieved

  5. Nonequilibrium clumped isotope signals in microbial methane

    Science.gov (United States)

    Wang, David T.; Gruen, Danielle S.; Lollar, Barbara Sherwood; Hinrichs, Kai-Uwe; Stewart, Lucy C.; Holden, James F.; Hristov, Alexander N.; Pohlman, John W.; Morrill, Penny L.; Könneke, Martin; Delwiche, Kyle B.; Reeves, Eoghan P.; Sutcliffe, Chelsea N.; Ritter, Daniel J.; Seewald, Jeffrey S.; McIntosh, Jennifer C.; Hemond, Harold F.; Kubo, Michael D.; Cardace, Dawn; Hoehler, Tori M.; Ono, Shuhei

    2015-01-01

    Methane is a key component in the global carbon cycle with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply-substituted “clumped” isotopologues, e.g., 13CH3D, has recently emerged as a proxy for determining methane-formation temperatures; however, the impact of biological processes on methane’s clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on 13CH3D abundances and results in anomalously elevated formation temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.

  6. Decarbonisation of fossil energy via methane pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kreysa, G.; Agar, D.W.; Schultz, I. [Technische Univ. Dortmund (Germany)

    2010-12-30

    Despite the rising consumption of energy over the last few decades, the proven reserves of fossil fuels have steadily increased. Additionally, there are potentially tremendous reserves of methane hydrates available, which remain to be exploited. The use of fossil energy sources is thus increasingly being dictated less by supply than by the environmental concerns raised by climate change. In the context of the decarbonisation of the global energy system that this has stimulated, new means must be explored for using methane as energy source. Noncatalytic thermal pyrolysis of methane is proposed here as a promising concept for utilising methane with low to zero carbon dioxide emissions. Following cracking, only the energy content of the hydrogen is used, while the carbon can be stored safely and retrievably in disused coal mines. The thermodynamics and different process engineering concepts for the technical realisation of such a carbon moratorium technology are discussed. The possible contribution of methane pyrolysis to carbon negative geoengineering is also addressed. (orig.)

  7. Enteric methane emissions from German dairy cows

    DEFF Research Database (Denmark)

    Dammgen, U; Rosemann, C; Haenel, H D

    2012-01-01

    Up to now, the German agricultural emission inventory used a model for the assessment of methane emissions from enteric fermentation that combined an estimate of the energy and feed requirements as a function of performance parameters and diet composition, with the constant methane conversion rate......, as stated by IPCC. A methane emission model was selected here that is based on German feed data. It was combined with the hitherto applied model describing energy requirements. The emission rates thus calculated deviate from those previously obtained. In the new model, the methane conversion rate is back......-calculated from emission rates and gross energy intake rates. For German conditions of animal performance and diet composition, the national means of methane conversion rates range between 71 kJ MJ(-1) and 61 kJ MJ(-1) for low and high performances (4700 kg animal(-1) a(-1) in 1990 to 7200 kg animal(-1) a(-1...

  8. Greenhouse effect contributions of US landfill methane

    International Nuclear Information System (INIS)

    Augenstein, D.

    1991-01-01

    The greenhouse effect has recently been receiving a great deal of scientific and popular attention. The term refers to a cause-and-effect relationship in which ''heat blanketing'' of the earth, due to trace gas increases in the atmosphere, is expected to result in global warming. The trace gases are increasing as the result of human activities. Carbon dioxide (CO 2 ) is the trace gas contributing most importantly to the ''heat blanketing'' and currently receives the most attention. Less widely recognized has been the high importance of methane (CH 4 ). Methane's contribution to the increased heat blanketing occurring since 1980 is estimated to be over a third as much as that of carbon dioxide. Gas from landfills has in turn been recognized to be a source of methane to the atmospheric buildup. However the magnitude of the landfill methane contribution, and the overall significance of landfill methane to the greenhouse phenomenon has been uncertain and the subject of some debate. (Author)

  9. The direct aromatization of methane

    Energy Technology Data Exchange (ETDEWEB)

    Marcelin, G.; Oukaci, R.; Migone, R.A.; Kazi, A.M. [Altamira Instruments, Pittsburgh, PA (United States)

    1995-12-31

    The thermal decomposition of methane shows significant potential as a process for the production of higher unsaturated and aromatic hydrocarbons when the extent of the reaction is limited. Thermodynamic calculations have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that when the reaction is limited to the formation of C{sub 2} to C{sub 10} products, yields of aromatics can exceed 40% at temperatures of 1200{degrees}C. Preliminary experiments have shown that cooling the product and reacting gases as the reaction proceeds can significantly reduce or eliminate the formation of solid carbon and heavier (C{sub 10+}) materials. Much work remains to be done in optimizing the quenching process and this is one of the goals of this program. Means to lower the temperature of the reaction are being studied as this result in a more feasible commercial process due to savings realized in energy and material of construction costs. The use of free-radical generators and catalysts will be investigated as a means of lowering the reaction temperature thus allowing faster quenching. It is highly likely that such studies will lead to a successful direct methane to higher hydrocarbon process.

  10. Methane measurements manual; Handbok metanmaetningar

    Energy Technology Data Exchange (ETDEWEB)

    Holmgren, Magnus Andreas (SP Technical research institute of Sweden, Boraas (Sweden))

    2011-02-15

    Emissions to air in different parts of the system may arise in biogas plants, where there is biological treatment of organic matter by anaerobic degradation, and during upgrading of biogas to vehicle fuel. There are mainly four reasons why these emissions must be minimized. These are safety, greenhouse gas emissions, economy and smell. This manual gathers experience of several years of work with measurement of methane emissions from biogas and upgrading facilities. This work has been done mainly in the context of Swedish Waste Management's system of voluntary commitment. The purpose of this manual is to standardize methods and procedures when methane measurements are carried out so that the results are comparable between different providers. The main target group of the manual is measurement consultants performing such measurements. Calculation template in Excel is part of the manual, which further contributes to the measurements evaluated in a standardized way. The manual contains several examples which have been calculated in the accompanying Excel template. The handbook also contains a chapter mainly intended for facility staff, in which implementation of accurate leak detection is described, and where there are hints of a system of so-called intermediate inspections to detect leaks in time

  11. Biochemically enhanced methane production from coal

    Science.gov (United States)

    Opara, Aleksandra

    For many years, biogas was connected mostly with the organic matter decomposition in shallow sediments (e.g., wetlands, landfill gas, etc.). Recently, it has been realized that biogenic methane production is ongoing in many hydrocarbon reservoirs. This research examined microbial methane and carbon dioxide generation from coal. As original contributions methane production from various coal materials was examined in classical and electro-biochemical bench-scale reactors using unique, developed facultative microbial consortia that generate methane under anaerobic conditions. Facultative methanogenic populations are important as all known methanogens are strict anaerobes and their application outside laboratory would be problematic. Additional testing examined the influence of environmental conditions, such as pH, salinity, and nutrient amendments on methane and carbon dioxide generation. In 44-day ex-situ bench-scale batch bioreactor tests, up to 300,000 and 250,000 ppm methane was generated from bituminous coal and bituminous coal waste respectively, a significant improvement over 20-40 ppm methane generated from control samples. Chemical degradation of complex hydrocarbons using environmentally benign reagents, prior to microbial biodegradation and methanogenesis, resulted in dissolution of up to 5% bituminous coal and bituminous coal waste and up to 25% lignite in samples tested. Research results confirm that coal waste may be a significant underutilized resource that could be converted to useful fuel. Rapid acidification of lignite samples resulted in low pH (below 4.0), regardless of chemical pretreatment applied, and did not generate significant methane amounts. These results confirmed the importance of monitoring and adjusting in situ and ex situ environmental conditions during methane production. A patented Electro-Biochemical Reactor technology was used to supply electrons and electron acceptor environments, but appeared to influence methane generation in a

  12. San Francisco Bay Water Quality Improvement Fund

    Science.gov (United States)

    EPAs grant program to protect and restore San Francisco Bay. The San Francisco Bay Water Quality Improvement Fund (SFBWQIF) has invested in 58 projects along with 70 partners contributing to restore wetlands, water quality, and reduce polluted runoff.,

  13. Funding Opportunities in the Chesapeake Bay Watershed

    Science.gov (United States)

    This page provides links to financial assistance opportunities to help the Chesapeake Bay jurisdictions (Delaware, District of Columbia, Maryland, New York, Pennsylvania, Virginia, and West Virginia) restore the Chesapeake Bay.

  14. Humboldt Bay, California Benthic Habitats 2009 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  15. Humboldt Bay, California Benthic Habitats 2009 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  16. Humboldt Bay, California Benthic Habitats 2009 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  17. 77 FR 18739 - Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2012-03-28

    ...-AA00 Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS. ACTION: Notice of... of Presque Island Bay, Erie, PA. This proposed safety zone is intended to restrict vessels from a... will take place on Presque Isle Bay near Erie, PA. The Captain of the Port Buffalo has determined that...

  18. 75 FR 36292 - Safety Zone; Bay Swim III, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2010-06-25

    ... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 165 [Docket No. USCG-2010-0529] RIN 1625-AA00 Safety Zone; Bay Swim III, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS. ACTION: Temporary... read as follows: Sec. 165.T09-0529 Safety Zone; Bay Swim III, Presque Isle Bay, Erie, PA (a) Location...

  19. 77 FR 2972 - Thunder Bay Power Company, Thunder Bay Power, LLC, et al.

    Science.gov (United States)

    2012-01-20

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Thunder Bay Power Company, Thunder Bay Power, LLC, et al.; Notice of Application for Transfer of Licenses, and Soliciting Comments and Motions To Intervene Thunder Bay Power Company Project No. 2404-095 Thunder Bay Power, LLC Midwest Hydro, Inc...

  20. 77 FR 70891 - Safety Zone; Bay Bridge Construction, San Francisco Bay, San Francisco, CA

    Science.gov (United States)

    2012-11-28

    ...-AA00 Safety Zone; Bay Bridge Construction, San Francisco Bay, San Francisco, CA AGENCY: Coast Guard... construction of the Bay Bridge, the safety zone is necessary to provide for the safety of mariners transiting... zones (33 U.S.C. 1221 et seq.). CALTRANS will sponsor the Bay Bridge Construction Safety Zone on...

  1. 78 FR 27989 - Bandon Marsh, Nestucca Bay, and Siletz Bay National Wildlife Refuges, Coos, Tillamook, and...

    Science.gov (United States)

    2013-05-13

    ... comments regarding the separate Bandon Marsh NWR Land Protection Planning (LPP) process will be considered...] Bandon Marsh, Nestucca Bay, and Siletz Bay National Wildlife Refuges, Coos, Tillamook, and Lincoln... Assessments (EAs) for three Oregon refuges--Bandon Marsh, Nestucca Bay, and Siletz Bay National Wildlife...

  2. Bayes linear statistics, theory & methods

    CERN Document Server

    Goldstein, Michael

    2007-01-01

    Bayesian methods combine information available from data with any prior information available from expert knowledge. The Bayes linear approach follows this path, offering a quantitative structure for expressing beliefs, and systematic methods for adjusting these beliefs, given observational data. The methodology differs from the full Bayesian methodology in that it establishes simpler approaches to belief specification and analysis based around expectation judgements. Bayes Linear Statistics presents an authoritative account of this approach, explaining the foundations, theory, methodology, and practicalities of this important field. The text provides a thorough coverage of Bayes linear analysis, from the development of the basic language to the collection of algebraic results needed for efficient implementation, with detailed practical examples. The book covers:The importance of partial prior specifications for complex problems where it is difficult to supply a meaningful full prior probability specification...

  3. Contaminant transport in Massachusetts Bay

    Science.gov (United States)

    Butman, Bradford

    Construction of a new treatment plant and outfall to clean up Boston Harbor is currently one of the world's largest public works projects, costing about $4 billion. There is concern about the long-term impact of contaminants on Massachusetts Bay and adjacent Gulf of Maine because these areas are used extensively for transportation, recreation, fishing, and tourism, as well as waste disposal. Public concern also focuses on Stellwagen Bank, located on the eastern side of Massachusetts Bay, which is an important habitat for endangered whales. Contaminants reach Massachusetts Bay not only from Boston Harbor, but from other coastal communities on the Gulf of Maine, as well as from the atmosphere. Knowledge of the pathways, mechanisms, and rates at which pollutants are transported throughout these coastal environments is needed to address a wide range of management questions.

  4. Off limits: sulfate below the sulfate-methane transition

    Science.gov (United States)

    Brunner, Benjamin; Arnold, Gail; Røy, Hans; Müller, Inigo; Jørgensen, Bo

    2016-07-01

    One of the most intriguing recent discoveries in biogeochemistry is the ubiquity of cryptic sulfur cycling. From subglacial lakes to marine oxygen minimum zones, and in marine sediments, cryptic sulfur cycling - the simultaneous sulfate consumption and production - has been observed. Though this process does not leave an imprint in the sulfur budget of the ambient environment - thus the term cryptic - it may have a massive impact on other element cycles and fundamentally change our understanding of biogeochemical processes in the subsurface. Classically, the sulfate-methane transition (SMT) in marine sediments is considered to be the boundary that delimits sulfate reduction from methanogenesis as the predominant terminal pathway of organic matter mineralization. Two sediment cores from Aarhus Bay, Denmark reveal the constant presence of sulfate (generally 0.1 to 0.2 mM) below the SMT. The sulfur and oxygen isotope signature of this deep sulfate (34S = 18.9‰, 18O = 7.7‰) was close to the isotope signature of bottom-seawater collected from the sampling site (34S = 19.8‰, 18O = 7.3‰). In one of the cores, oxygen isotope values of sulfate at the transition from the base of the SMT to the deep sulfate pool (18O = 4.5‰ to 6.8‰) were distinctly lighter than the deep sulfate pool. Our findings are consistent with a scenario where sulfate enriched in 34S and 18O is removed at the base of the SMT and replaced with isotopically light sulfate below. Here, we explore scenarios that explain this observation, ranging from sampling artifacts, such as contamination with seawater or auto-oxidation of sulfide - to the potential of sulfate generation in a section of the sediment column where sulfate is expected to be absent which enables reductive sulfur cycling, creating the conditions under which sulfate respiration can persist in the methanic zone.

  5. Automation in tube finishing bay

    International Nuclear Information System (INIS)

    Bhatnagar, Prateek; Satyadev, B.; Raghuraman, S.; Syama Sundara Rao, B.

    1997-01-01

    Automation concept in tube finishing bay, introduced after the final pass annealing of PHWR tubes resulted in integration of number of sub-systems in synchronisation with each other to produce final cut fuel tubes of specified length, tube finish etc. The tube finishing bay which was physically segregated into four distinct areas: 1. tube spreader and stacking area, 2. I.D. sand blasting area, 3. end conditioning, wad blowing, end capping and O.D. wet grinding area, 4. tube inspection, tube cutting and stacking area has been studied

  6. Review of methane mitigation technologies with application to rapid release of methane from the Arctic.

    Science.gov (United States)

    Stolaroff, Joshuah K; Bhattacharyya, Subarna; Smith, Clara A; Bourcier, William L; Cameron-Smith, Philip J; Aines, Roger D

    2012-06-19

    Methane is the most important greenhouse gas after carbon dioxide, with particular influence on near-term climate change. It poses increasing risk in the future from both direct anthropogenic sources and potential rapid release from the Arctic. A range of mitigation (emissions control) technologies have been developed for anthropogenic sources that can be developed for further application, including to Arctic sources. Significant gaps in understanding remain of the mechanisms, magnitude, and likelihood of rapid methane release from the Arctic. Methane may be released by several pathways, including lakes, wetlands, and oceans, and may be either uniform over large areas or concentrated in patches. Across Arctic sources, bubbles originating in the sediment are the most important mechanism for methane to reach the atmosphere. Most known technologies operate on confined gas streams of 0.1% methane or more, and may be applicable to limited Arctic sources where methane is concentrated in pockets. However, some mitigation strategies developed for rice paddies and agricultural soils are promising for Arctic wetlands and thawing permafrost. Other mitigation strategies specific to the Arctic have been proposed but have yet to be studied. Overall, we identify four avenues of research and development that can serve the dual purposes of addressing current methane sources and potential Arctic sources: (1) methane release detection and quantification, (2) mitigation units for small and remote methane streams, (3) mitigation methods for dilute (<1000 ppm) methane streams, and (4) understanding methanotroph and methanogen ecology.

  7. Determining the flux of methane into Hudson Canyon at the edge of methane clathrate hydrate stability

    Science.gov (United States)

    Weinsten, A.; Navarrete, L; Ruppel, Carolyn D.; Weber, T.C.; Leonte, M.; Kellermann, M.; Arrington, E.; Valentine, D.L.; Scranton, M.L; Kessler, John D.

    2016-01-01

    Methane seeps were investigated in Hudson Canyon, the largest shelf-break canyon on the northern US Atlantic Margin. The seeps investigated are located at or updip of the nominal limit of methane clathrate hydrate stability. The acoustic identification of bubble streams was used to guide water column sampling in a 32 km2 region within the canyon's thalweg. By incorporating measurements of dissolved methane concentration with methane oxidation rates and current velocity into a steady-state box model, the total emission of methane to the water column in this region was estimated to be 12 kmol methane per day (range: 6 – 24 kmol methane per day). These analyses suggest this methane is largely retained inside the canyon walls below 300 m water depth, and that it is aerobically oxidized to near completion within the larger extent of Hudson Canyon. Based on estimated methane emissions and measured oxidation rates, the oxidation of this methane to dissolved CO2 is expected to have minimal influences on seawater pH. This article is protected by copyright. All rights reserved.

  8. Estuarine Sediment Budgets for Chesapeake Bay Tributaries

    Science.gov (United States)

    2012-09-01

    2003. Estuarine sediment sources: A Summary Report of Sediment Processes in Chesapeake Bay and Watershed . Water-Resources Investigations Report 03...2007. Sources and transport of sediment in the watershed : Synthesis of US Geological Survey science for the Chesapeake Bay ecosystem and...originator. Estuarine Sediment Budgets for Chesapeake Bay Tributaries by Julie D. Herman PURPOSE. This Coastal and Hydraulics Engineering

  9. Metagenomic evidence for reciprocal particle exchange between the mainstem estuary and lateral bay sediments of the lower Columbia River

    Directory of Open Access Journals (Sweden)

    Mariya W Smith

    2015-10-01

    Full Text Available Lateral bays of the lower Columbia River estuary are areas of enhanced water retention that influence net ecosystem metabolism through activities of their diverse microbial communities. Metagenomic characterization of sediment microbiota from three disparate sites in two brackish lateral bays (Baker and Youngs produced approximately 100 Gbp of DNA sequence data analyzed subsequently for predicted SSU rRNA and peptide-coding genes. The metagenomes were dominated by Bacteria. A large component of Eukaryota was present in Youngs Bay samples, i.e. the inner bay sediment was enriched with the invasive New Zealand mudsnail, Potamopyrgus antipodarum, known for high ammonia production. The metagenome was also highly enriched with an archaeal ammonia oxidizer closely related to Nitrosoarchaeum limnia. Combined analysis of sequences and continuous, high-resolution time series of biogeochemical data from fixed and mobile platforms revealed the importance of large-scale reciprocal particle exchanges between the mainstem estuarine water column and lateral bay sediments. Deposition of marine diatom particles in sediments near Youngs Bay mouth was associated with a dramatic enrichment of Bacteroidetes (58% of total Bacteria and corresponding genes involved in phytoplankton polysaccharide degradation. The Baker Bay sediment metagenome contained abundant Archaea, including diverse methanogens, as well as functional genes for methylotrophy and taxonomic markers for syntrophic bacteria, suggesting that active methane cycling occurs at this location. Our previous work showed enrichments of similar anaerobic taxa in particulate matter of the mainstem estuarine water column. In total, our results identify the lateral bays as both sources and sinks of biogenic particles significantly impacting microbial community composition and biogeochemical activities in the estuary.

  10. Low-Altitude Aerial Methane Concentration Mapping

    Directory of Open Access Journals (Sweden)

    Bara J. Emran

    2017-08-01

    Full Text Available Detection of leaks of fugitive greenhouse gases (GHGs from landfills and natural gas infrastructure is critical for not only their safe operation but also for protecting the environment. Current inspection practices involve moving a methane detector within the target area by a person or vehicle. This procedure is dangerous, time consuming, labor intensive and above all unavailable when access to the desired area is limited. Remote sensing by an unmanned aerial vehicle (UAV equipped with a methane detector is a cost-effective and fast method for methane detection and monitoring, especially for vast and remote areas. This paper describes the integration of an off-the-shelf laser-based methane detector into a multi-rotor UAV and demonstrates its efficacy in generating an aerial methane concentration map of a landfill. The UAV flies a preset flight path measuring methane concentrations in a vertical air column between the UAV and the ground surface. Measurements were taken at 10 Hz giving a typical distance between measurements of 0.2 m when flying at 2 m/s. The UAV was set to fly at 25 to 30 m above the ground. We conclude that besides its utility in landfill monitoring, the proposed method is ready for other environmental applications as well as the inspection of natural gas infrastructure that can release methane with much higher concentrations.

  11. 30 CFR 75.1324 - Methane concentration and tests.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Methane concentration and tests. 75.1324... Methane concentration and tests. (a) No shot shall be fired in an area that contains 1.0 volume percent or more of methane. (b) Immediately before shots are fired, the methane concentration in a working place...

  12. 30 CFR 27.22 - Methane detector component.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Methane detector component. 27.22 Section 27.22... APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Construction and Design Requirements § 27.22 Methane detector component. (a) A methane detector component shall be suitably constructed for incorporation in or...

  13. Status of the methanization sector in France

    International Nuclear Information System (INIS)

    2011-09-01

    This report aims at describing the status of methanization installations, either operating or under construction, on the French national territory, all sectors included (industry, agriculture, sewage treatment, municipal wastes). In a first part, the authors propose a definition of methanization, a presentation of the various implementation techniques, a presentation of the different sectors using methanization (industry, agriculture and breeding, sewage treatment plants, household wastes), and a presentation of a survey. Then, they comment and discuss more precisely the different sectors, their history, their geographical distribution in France, their technologies, their effluents, their production, their economic data, their perspectives

  14. East bay fire chiefs' consortium

    Science.gov (United States)

    Michael Bradley

    1995-01-01

    The traditional approach to planning for public fire protection has been based on independent actions by each fire department or district. The county fire chiefs’ associations, while providing interagency communication, were not adequate to deal with the regional nature of the wildland urban interface problem. The formation of the East Bay Fire Chiefs’ Consortium grew...

  15. Backscatter imagery in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1x1 meter resolution backscatter mosaic of Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The backscatter values are in relative 8-bit (0 –...

  16. Quantification of the methane concentration using anaerobic oxidation of methane coupled to extracellular electron transfer.

    Science.gov (United States)

    Gao, Yaohuan; Ryu, Hodon; Rittmann, Bruce E; Hussain, Abid; Lee, Hyung-Sool

    2017-10-01

    A biofilm anode acclimated with growth media containing acetate, then acetate+methane, and finally methane alone produced electrical current in a microbial electrochemical cell (MxC) fed with methane as the sole electron donor. Geobacter was the dominant genus for the bacterial domain (93%) in the biofilm anode, while methanogens (Methanocorpusculum labreanum and Methanosaeta concilii) accounted for 82% of the total archaeal clones in the biofilm. Fluorescence in situ hybridization (FISH) imaging clearly showed a biofilm of mixed bacteria and archaea, suggesting a syntrophic interaction between them for performing anaerobic oxidation of methane (AOM) in the biofilm anode. Measured cumulative coulombs were linearly correlated to the methane-gas concentration in the range of 10-99.97% (R 2 ≥0.99) when the measurement was sustained for at least 50min Thus, cumulative coulombs over 50min could be used to quantify the methane concentration in gas samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Classification using Hierarchical Naive Bayes models

    DEFF Research Database (Denmark)

    Langseth, Helge; Dyhre Nielsen, Thomas

    2006-01-01

    Classification problems have a long history in the machine learning literature. One of the simplest, and yet most consistently well-performing set of classifiers is the Naïve Bayes models. However, an inherent problem with these classifiers is the assumption that all attributes used to describe......, termed Hierarchical Naïve Bayes models. Hierarchical Naïve Bayes models extend the modeling flexibility of Naïve Bayes models by introducing latent variables to relax some of the independence statements in these models. We propose a simple algorithm for learning Hierarchical Naïve Bayes models...

  18. Wave-induced release of methane : littoral zones as a source of methane in lakes

    OpenAIRE

    Hofmann, Hilmar; Federwisch, Luisa; Peeters, Frank

    2010-01-01

    This study investigates the role of surface waves and the associated disturbance of littoral sediments for the release and later distribution of dissolved methane in lakes. Surface wave field, wave-induced currents, acoustic backscatter strength, and the concentration and distribution of dissolved methane were measured simultaneously in Lake Constance, Germany. The data indicate that surface waves enhance the release of dissolved methane in the shallow littoral zone via burst-like releases of...

  19. Wetlands the primary source of Amazon Basin methane

    Science.gov (United States)

    Schultz, Colin

    2012-11-01

    The Amazon basin is an important sink of carbon dioxide, but it is also a substantial source of atmospheric methane. Tropical wetlands, including those in the Amazon, are one of the largest sources of biogenic methane and globally represent roughly 13% of annual emissions of the greenhouse gas. Other sources of methane include fossil fuel or biomass burning. Through two intensive atmospheric methane sampling campaigns, Beck et al. determined the sources of Amazonian methane.

  20. METHOD FOR PRODUCING ISOTOPIC METHANES AND PARTIALLY HALOGENATED DERIVATIVES THEROF

    Science.gov (United States)

    Frazer, J.W.

    1959-08-18

    A method is given for producing isotopic methanes and/ or partially halogenated derivatives. Lithium hydride, deuteride, or tritide is reacted with a halogenated methane or with a halogenated methane in combination with free halogen. The process is conveniently carried out by passing a halogenated methane preferably at low pressures or in an admixture with an inert gas through a fixed bed of finely divided lithium hydride heated initially to temperatures of 100 to 200 deg C depending upon the halogenated methane used.

  1. Biocatalytic conversion of methane to methanol as a key step for development of methane-based biorefineries.

    Science.gov (United States)

    Hwang, In Yeub; Lee, Seung Hwan; Choi, Yoo Seong; Park, Si Jae; Na, Jeong Geol; Chang, In Seop; Kim, Choongik; Kim, Hyun Cheol; Kim, Yong Hwan; Lee, Jin Won; Lee, Eun Yeol

    2014-12-28

    Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology.

  2. Formation temperatures of thermogenic and biogenic methane

    Science.gov (United States)

    Stolper, D.A.; Lawson, M.; Davis, C.L.; Ferreira, A.A.; Santos Neto, E. V.; Ellis, G.S.; Lewan, M.D.; Martini, Anna M.; Tang, Y.; Schoell, M.; Sessions, A.L.; Eiler, J.M.

    2014-01-01

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a “clumped isotope” technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

  3. Livestock-environment interactions: Methane emissions from ...

    African Journals Online (AJOL)

    user

    2011-02-21

    , T.1*, Wuyep, .... nogens play a key ecological role in keeping the partial pressure of hydrogen low so that fermentation ..... Ecology of methane production and hydrogen sinks in the rumen, In: Engelhardt WV, Leonhard-Marek ...

  4. Methane leakage in natural gas operations

    International Nuclear Information System (INIS)

    Jennervik, A.

    1992-01-01

    The world gas industry is efficient in conservation of natural gas within its systems. As the influence of methane as an infra-red absorbent gas has been more widely recognized, the considerations of methane's greenhouse effect has become vitally important to gas companies around the world. The industry is universally environmentally conscious. natural gas transmission and distribution companies want to maintain their image as suppliers of clean fuel. Further reductions in methane leakage --- particularly in older distribution systems --- can, should and will be pursued. Unfortunately, there has been little exchange of views on methane leakages between commentators on environmental matters and gas companies and organizations. There is absolutely no need for the industry to avoid the issue of greenhouse gases. Without industry involvement, the environmental debate concerning fossil fuels could lead to selective interpretation of scientific views and available evidence. Companies and authorities would be presented with confusing, contradictory evidence on which to base policy approaches and regulations

  5. Methane Tracking and Mitigation Options - EPA CMOP

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset contains the sub-model for EPA's MARKAL model, which tracks methane emissions from the energy system, and limited other sources (landfills and manure...

  6. Global climate: Methane contribution to greenhouse effect

    International Nuclear Information System (INIS)

    Metalli, P.

    1992-01-01

    The global atmospheric concentration of methane greatly contributes to the severity of the greenhouse effect. It has been estimated that this concentration, due mainly to human activities, is growing at the rate of roughly 1.1% per year. Environmental scientists suggest that a reduction, even as small as 10%, in global methane emissions would be enough to curtail the hypothetical global warning scenarios forecasted for the up-coming century. Through the recovery of methane from municipal and farm wastes, as well as, through the control of methane leaks and dispersions in coal mining and petrochemical processes, substantial progress towards the abatement of greenhouse gas effects could be achieved without having to resort to economically detrimental limitations on the use of fossil fuels

  7. Oxygen-Methane Thruster, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Two main innovations will be developed in the Phase II effort that are fundamentally associated with our gaseous oxygen/gaseous methane RCS thruster. The first...

  8. SUPPLEMENTARY INFORMATION Non-oxidative methane ...

    Indian Academy of Sciences (India)

    dell

    SUPPLEMENTARY INFORMATION. Non-oxidative methane dehydroaromatization reaction over highly active α-MoC1-x ZSM-5 derived from pretreatment. BUDDE PRADEEP KUMAR, ARVIND KUMAR SINGH and SREEDEVI UPADHYAYULA*. Heterogeneous Catalysis & Reaction Engineering Laboratory, Department of ...

  9. Enteric methane emissions from German pigs

    DEFF Research Database (Denmark)

    Dämmgen, Ulrich; Schulz, Joachim; Klausing, Heinrich Kleine

    2012-01-01

    Methane emissions from enteric fermentation of pigs are object of emission reporting. Hitherto they were treated as part of the energy balance of pigs, in accordance with IPCC guidance documents. They were calculated from the gross energy intake rate and a constant methane conversion ratio....... Meanwhile numerous experimental data on methane emissions from enteric fermentation is available in Germany and abroad; the results are compiled in this work. These results also allow for a description of transformation processes in the hind gut and a subsequent establishment of models that relate emissions...... to feed and performance data. The model by Kirchgeßner et al. (1995) is based on German experimental data and reflects typical national diet compositions. It is used to quantify typical emissions and methane conversion ratios. The results agree with other experimental findings at home and abroad...

  10. Methane Lidar Transmitter Development for Space

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this work is to advance the technology readiness level (TRL) of lidar system to enable global Methane (CH4) and water vapor (H2O) measurements with...

  11. Neutron powder diffraction study of methane hydrate

    International Nuclear Information System (INIS)

    Ishii, Yoshinobu

    2005-01-01

    Neutron powder diffraction study of methane hydrate has been conducted in the temperature range of 7 K to 185 K. The diffraction data were analyzed by the Rietveld refinement and the Maximum Entropy Method (MEM). From MEM analysis, we obtained the scattering-length density distributions in a 3-dimensional image. The scattering-length density corresponding to C atom of the methane molecule was appeared and no density of H atoms was found in the small cage over the measured temperature range. On the other hand, in the large cage the scattering-length densities related to both H atom and C atom were observed at low temperature. The scattering-length density of H atom disappeared with increasing temperature, and then the scattering-length density of methane was almost gone at high temperature. These results show the motion of methane molecules differ in the small cage as compared to the large cage

  12. Oxygen-Methane Thruster, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Orion Propulsion, Inc. proposes to develop an Oxygen and Methane RCS Thruster to advance the technology of alternate fuels. A successful Oxygen/CH4 RCS Thruster will...

  13. Dissolved methane in Indian freshwater reservoirs

    Digital Repository Service at National Institute of Oceanography (India)

    Narvenkar, G.; Naqvi, S.W.A.; Kurian, S.; Shenoy, D.M.; Pratihary, A.K.; Naik, H.; Patil, S.; Sarkar, A.; Gauns, M.

    Emission of methane (CH4), a potent greenhouse gas, from tropical reservoirs is of interest because such reservoirs experience conducive conditions for CH4 production through anaerobic microbial activities. It has been suggested that Indian...

  14. Bio-methane. Challenges and technical solutions

    International Nuclear Information System (INIS)

    Blaisonneau, Laurent; Carlu, Elieta; Feuillette, Vincent

    2012-06-01

    Among the new energy sectors in development, biogas has many benefits: several valorization possibilities (bio-methane, electricity and heat), continuous production, easy storage. In Europe, and particularly in France, the bio-methane market will be in the next years a driver for the improvement of the economic, environmental and social performance of the actors of the value chain of biogas. ENEA releases a report on the current state of the bio-methane market in Europe. This publication mainly describes: An outlook of the market evolution and the corresponding stakes for the actors of this sector, the technical and economic characteristics, maturity level and specificities of each biogas upgrading process, An analysis of the French regulatory framework for bio-methane injection into the grid

  15. Producing Hydrogen by Plasma Pyrolysis of Methane

    Science.gov (United States)

    Atwater, James; Akse, James; Wheeler, Richard

    2010-01-01

    Plasma pyrolysis of methane has been investigated for utility as a process for producing hydrogen. This process was conceived as a means of recovering hydrogen from methane produced as a byproduct of operation of a life-support system aboard a spacecraft. On Earth, this process, when fully developed, could be a means of producing hydrogen (for use as a fuel) from methane in natural gas. The most closely related prior competing process - catalytic pyrolysis of methane - has several disadvantages: a) The reactor used in the process is highly susceptible to fouling and deactivation of the catalyst by carbon deposits, necessitating frequent regeneration or replacement of the catalyst. b) The reactor is highly susceptible to plugging by deposition of carbon within fixed beds, with consequent channeling of flow, high pressure drops, and severe limitations on mass transfer, all contributing to reductions in reactor efficiency. c) Reaction rates are intrinsically low. d) The energy demand of the process is high.

  16. Coupled radon, methane and nitrate sensors for large-scale assessment of groundwater discharge and non-point source pollution to coastal waters.

    Science.gov (United States)

    Dulaiova, Henrieta; Camilli, Richard; Henderson, Paul B; Charette, Matthew A

    2010-07-01

    We constructed a survey system of radon/methane/nitrate/salinity to find sites of submarine groundwater discharge (SGD) and groundwater nitrate input. We deployed the system in Waquoit Bay and Boston Harbor, MA where we derived SGD rates using a mass balance of radon with methane serving as a fine resolution qualitative indicator of groundwater. In Waquoit Bay we identified several locations of enhanced groundwater discharge, out of which two (Childs and Quashnet Rivers) were studied in more detail. The Childs River was characterized by high nitrate input via groundwater discharge, while the Quashnet River SGD was notable but not a significant source of nitrate. Our radon survey of Boston Harbor revealed several sites with significant SGD, out of these Inner Harbor and parts of Dorchester Bay and Quincy Bay had groundwater fluxes accompanied by significant water column nitrogen concentrations. The survey system has proven effective in revealing areas of SGD and non-point source pollution. 2009 Elsevier Ltd. All rights reserved.

  17. Enhancement of methane production from barley waste

    OpenAIRE

    Neves, L.; Ribeiro, R.; Oliveira, Rosário; Alves, M. M.

    2006-01-01

    Two different approaches were attempted to try and enhance methane production from an industrial waste composed of 100% barley, which results from production of instant coffee substitutes. In previous work, this waste was co-digested with an excess of activated sludge produced in the wastewater treatment plant located in same industrial unit, resulting in a very poor methane yield (25LCH4(STP)/ kgVSinitial), and low reductions in total solids (31%) and in volatile solids (40%). Wh...

  18. Seasonal total methane depletion in limestone caves

    OpenAIRE

    Waring Chris L; Hankin Stuart I; Griffith David W T; Kertesz Michael A; Kobylski Victoria; Wilson Neil L; Coleman Nicholas V; Kettlewell Graham; Zlot Robert; Bosse Michael; Bell Graham

    2017-01-01

    Methane concentration in caves is commonly much lower than the external atmosphere, yet the cave CH4 depletion causal mechanism is contested and dynamic links to external diurnal and seasonal temperature cycles unknown. Here, we report a continuous 3-year record of cave methane and other trace gases in Jenolan Caves, Australia which shows a seasonal cycle of extreme CH4 depletion, from ambient ~1,775?ppb to near zero during summer and to ~800?ppb in winter. Methanotrophic bacteria, some newly...

  19. Methane emissions from the natural gas industry

    International Nuclear Information System (INIS)

    Harrison, M.R.; Cowgill, R.M.; Campbell, L.M.; Lott, R.A.

    1993-01-01

    The U.S. EPA and the United Nation's Intergovernmental Panel on Climate Change (IPCC) have suggested that global warming could be reduced if more energy was generated using natural gas rather than fuels such as coal. An increased use of natural gas instead of coal would decrease global warming since methane emits less carbon dioxide (CO 2 ) than any fossil fuel. However, methane is a more potent as a greenhouse gas than CO 2 , and leakage from the gas system could reduce or eliminate the inherent advantage of natural gas. For this reason, methane emissions must be quantified before a national policy on preferred fuels is developed. Therefore, GRI and EPA have developed this confunded program to quantify methane emissions from the U.S. gas industry. This paper presents, for general industry review, the approach and methodology that the project is using to determine the emissions. The study will measure or calculate all gas industry methane emissions - from production at the wellhead, through the system, to the customer's meter. When these data are combined with data from other studies, a definitive comparison of the relative environmental impact of using methane versus other fuels will be possible. The study will also provide data that can be used by the industry to identify cost-effective mitigation techniques to reduce losses. The methane emissions project is being conducted in three phases: the first two phases have identified and ranked all known potential methane-emitting sources and established methods for measuring, calculating, and extrapolating emissions from those sources. The third phase, which is currently in progress, will gather sufficient data to achieve the accuracy goal. This paper briefly summarizes the methodology being used for the completion of the third phase

  20. Upconversion detector for methane atmospheric sensor

    DEFF Research Database (Denmark)

    Meng, Lichun; Fix, Andreas; Høgstedt, Lasse

    2017-01-01

    We demonstrate an efficient upconversion detector (UCD) for a methane (CH4) atmospheric sensor. The UCD shows comparable performance with a conventional detector when measuring the backscattered signal from the hard target located 2.3 km away.......We demonstrate an efficient upconversion detector (UCD) for a methane (CH4) atmospheric sensor. The UCD shows comparable performance with a conventional detector when measuring the backscattered signal from the hard target located 2.3 km away....

  1. A biomimetic methane-oxidising catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, H. [Warwick Univ., Coventry (United Kingdom). Dept. of Biological Sciences

    1996-12-31

    The diminishing resources of petroleum oil has meant that there has been considerable efforts in recent years to find a suitable substitute for gasoline as a transportation fuel. Methanol has been identified as a suitable substitute since it is a readily combustible fuel which can be manufactured from a number of different sources. Methane is commonly used as a starting material for the production of synthesis gas (CO + H{sub 2}) and hence methanol. It is well known that the cleavage of the C-H bond of methane is extremely difficult (bond energy is around 104 kcal/mol) and that fairly drastic conditions are required to convert methane into methanol. Temperatures around 1200 deg C and pressures of up to 100 atmospheres over metal catalysts in a series of reactions are required to effect this process. Efforts have been made to reduce the temperature and the number of steps by using lanthanide ruthenium oxide catalyst but such reactions are still thermodynamically endothermic. An energetically more efficient reaction would be the direct conversion of methane to methanol using oxygen as the oxidant: CH{sub 4} + 1/2O{sub 2} -> CH{sub 3}OH {Delta}H deg = - 30.7 kcal/mol. Such a direct oxidation route is manifest in the bacterially-mediated oxidation of methane by methanotrophic bacteria. These organisms effect the direct oxidation of methane to methanol by the enzyme methane monooxygenase (MMO) as part of the reaction sequences to oxidize methane to carbon dioxide. (14 refs.)

  2. Prediction of enteric methane emissions from cattle.

    Science.gov (United States)

    Moraes, Luis E; Strathe, Anders B; Fadel, James G; Casper, David P; Kebreab, Ermias

    2014-07-01

    Agriculture has a key role in food production worldwide and it is a major component of the gross domestic product of several countries. Livestock production is essential for the generation of high quality protein foods and the delivery of foods in regions where animal products are the main food source. Environmental impacts of livestock production have been examined for decades, but recently emission of methane from enteric fermentation has been targeted as a substantial greenhouse gas source. The quantification of methane emissions from livestock on a global scale relies on prediction models because measurements require specialized equipment and may be expensive. The predictive ability of current methane emission models remains poor. Moreover, the availability of information on livestock production systems has increased substantially over the years enabling the development of more detailed methane prediction models. In this study, we have developed and evaluated prediction models based on a large database of enteric methane emissions from North American dairy and beef cattle. Most probable models of various complexity levels were identified using a Bayesian model selection procedure and were fitted under a hierarchical setting. Energy intake, dietary fiber and lipid proportions, animal body weight and milk fat proportion were identified as key explanatory variables for predicting emissions. Models here developed substantially outperformed models currently used in national greenhouse gas inventories. Additionally, estimates of repeatability of methane emissions were lower than the ones from the literature and multicollinearity diagnostics suggested that prediction models are stable. In this context, we propose various enteric methane prediction models which require different levels of information availability and can be readily implemented in national greenhouse gas inventories of different complexity levels. The utilization of such models may reduce errors

  3. Atmospheric Methane Measurements from an Aircraft Based at NASA Ames: Five Years of Observations by the AJAX Project

    Science.gov (United States)

    Iraci, Laura

    2016-01-01

    The Alpha Jet Atmospheric eXperiment (AJAX) is a research project based at Moffett Field, CA, which collects airborne measurements of ozone, carbon dioxide, methane, water vapor, and formaldehyde, as well as 3-D winds, temperature, pressure, and location. Since its first science flight in 2011, AJAX has developed a wide a variety of mission types, combining vertical profiles (from approx. 8 km to near surface),boundary layer legs, and plume sampling as needed. With an ongoing five-year data set, the team has sampled over 160 vertical profiles, a dozen wildfires, and numerous stratospheric ozone intrusions. This talk will present an overview of our flights flown to date, with particular focus on methane observations in the San Francisco Bay Area, Sacramento, and the delta region.

  4. Rotational spectra of methane and deuterated methane in helium.

    Science.gov (United States)

    Zillich, Robert E; Whaley, K Birgitta

    2010-05-07

    We present calculations of the rotational excitations of CH(4) and CD(4) in helium using correlated basis function theory for excited states of spherical top molecules, together with ground state helium density distributions computed by diffusion Monte Carlo simulations. We derive the rotational self-energy for symmetric top molecules, generalizing the previous analysis for linear molecules. The analysis of the self-energy shows that in helium the symmetry of a rigid spherical rotor is lost. In particular, rotational levels with J=2 split into states of E and of F(2) symmetry. This splitting can be analyzed in terms of an effective tetrahedral distortion that is induced by coupling of the molecular rotation to density fluctuations of the helium. Additional splitting occurs within each symmetry group as a result of rotational coupling to the high density of states between the roton and maxon excitations of (4)He, which also results in broad bands in the corresponding rotational absorption spectra. Connecting these pure rotational dynamics of methane to experimental rovibrational spectra, our results imply that the R(1) line of CH(4) is significantly broadened, while the P(2) is not broadened by rotational relaxation, which is consistent with experiment. Comparison of our results for CH(4) and CD(4) shows that the reduction in the moment of inertia in (4)He scales approximately quadratically with the gas phase moment of inertia, as has also been observed experimentally.

  5. Methanation of hydrogen and carbon dioxide

    International Nuclear Information System (INIS)

    Burkhardt, Marko; Busch, Günter

    2013-01-01

    Highlights: • The biologic methanation of exclusively gases like hydrogen and carbon dioxide is feasible. • Electrical energy can be stored in the established gas grid by conversion to methane. • The quality of produced biogas is very high (c CH4 = 98 vol%). • The conversion rate is depending on H 2 -flow rate. - Abstract: A new method for the methanation of hydrogen and carbon dioxide is presented. In a novel anaerobic trickle-bed reactor, biochemical catalyzed methanation at mesophilic temperatures and ambient pressure can be realized. The conversion of gaseous substrates by immobilized hydrogenotrophic methanogens is a unique feature of this reactor type. The already patented reactor produces biogas which has a very high quality (c CH4 = 97.9 vol%). Therefore, the storage of biogas in the existing natural gas grid is possible without extensive purification. The specific methane production was measured with P = 1.17 Nm CH4 3 /(m R 3 d). It is conceivable to realize the process at sites that generate solar or wind energy and sites subject to the conditions for hydrogen electrolysis (or other methods of hydrogen production). The combination with conventional biogas plants under hydrogen addition to methane enrichment is possible as well. The process enables the coupling of various renewable energy sources

  6. Airborne Methane Measurements using Optical Parametric Amplifiers

    Science.gov (United States)

    Riris, H.; Numata, K.; Li, S.; Wu, S.; Ramanathan, A.; Dawsey, M.; Abshire, J. B.; Kawa, S. R.; Mao, J.

    2012-12-01

    We report on airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planetary bodies. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Carbon and methane emissions from land are expected to increase as permafrost melts exposing millennial-age carbon stocks to respiration (aerobic-CO2 and anaerobic-CH4) and fires. Methane emissions from clathrates in the Arctic Ocean and on land are also likely to respond to climate warming. However, there is considerable uncertainty in present Arctic flux levels, as well as how fluxes will change with the changing environment and more measurements are needed. In this paper we report on an airborne demonstration of atmospheric methane column optical depth measurements at 1.65 μm using widely tunable, seeded optical parametric amplifier (OPA) and a photon counting detector. Our results show good agreement between the experimentally derived optical depth measurements and theoretical calculations and follow the expected changes for aircraft altitudes from 3 to 11 km. The technique has also been used to measure carbon dioxide and monoxide, water vapor, and other trace gases in the near and mid-infrared spectral regions on the ground.

  7. The Tritium Content of Atmospheric Methane

    International Nuclear Information System (INIS)

    Bishop, K.F.; Delafield, H.J.; Eggleton, A.E.J.; Peabody, C.O.; Taylor, B.T.

    1962-01-01

    The tritium content of atmospheric methane. The presence of significant amounts of tritium in atmospheric methane is reported. Methane extracted from air samples obtained from various altitudes in the northern and southern hemispheres showed T/H ratios ranging from 6.3 x 10 3 to 3.4 x 10 4 T.U. (1 T.U. equals a T/H ratio of 10 -18 ) during the period September 1957 to February 1959 and a continuous rise in the southern hemisphere from 9 x 10 2 T. U. in 1953 to 8 x 10 3 T. U. in 1958. Considerable short-term fluctuations were observed at Wembley, England. The tritiated methane distribution in 1958 was consistent with a tropospheric source (or sources) in the northern hemisphere and the Dobson-Brewer model of global stratospheric circulation. The global integral for tritium in the form of atmospheric methane was very roughly 2.3 x 10 5 c in 1958. No satisfactory explanation of the source of the tritiated methane has been found. (author) [fr

  8. The Chesapeake Bay impact structure

    Science.gov (United States)

    Powars, David S.; Edwards, Lucy E.; Gohn, Gregory S.; Horton, J. Wright

    2015-10-28

    About 35 million years ago, during late Eocene time, a 2-mile-wide asteroid or comet smashed into Earth in what is now the lower Chesapeake Bay in Virginia. The oceanic impact vaporized, melted, fractured, and (or) displaced the target rocks and sediments and sent billions of tons of water, sediments, and rocks into the air. Glassy particles of solidified melt rock rained down as far away as Texas and the Caribbean. Models suggest that even up to 50 miles away the velocity of the intensely hot air blast was greater than 1,500 miles per hour, and ground shaking was equivalent to an earthquake greater than magnitude 8.0 on the Richter scale. Large tsunamis affected most of the North Atlantic basin. The Chesapeake Bay impact structure is among the 20 largest known impact structures on Earth.

  9. Anaerobic methane oxidation in low-organic content methane seep sediments

    Science.gov (United States)

    Pohlman, John W.; Riedel, Michael; Bauer, James E.; Canuel, Elizabeth A.; Paull, Charles K.; Lapham, Laura; Grabowski, Kenneth S.; Coffin, Richard B.; Spence, George D.

    2013-01-01

    Sulfate-dependent anaerobic oxidation of methane (AOM) is the key sedimentary microbial process limiting methane emissions from marine sediments and methane seeps. In this study, we investigate how the presence of low-organic content sediment influences the capacity and efficiency of AOM at Bullseye vent, a gas hydrate-bearing cold seep offshore of Vancouver Island, Canada. The upper 8 m of sediment contains 14C. A fossil origin for the DIC precludes remineralization of non-fossil OM present within the sulfate zone as a significant contributor to pore water DIC, suggesting that nearly all sulfate is available for anaerobic oxidation of fossil seep methane. Methane flux from the SMT to the sediment water interface in a diffusion-dominated flux region of Bullseye vent was, on average, 96% less than at an OM-rich seep in the Gulf of Mexico with a similar methane flux regime. Evidence for enhanced methane oxidation capacity within OM-poor sediments has implications for assessing how climate-sensitive reservoirs of sedimentary methane (e.g., gas hydrate) will respond to ocean warming, particularly along glacially-influenced mid and high latitude continental margins.

  10. Methane distribution and methane oxidation in the water column of the Elbe estuary, Germany

    Czech Academy of Sciences Publication Activity Database

    Matoušů, Anna; Osudar, R.; Šimek, Karel; Bussmann, I.

    2017-01-01

    Roč. 79, č. 3 (2017), s. 443-458 ISSN 1015-1621 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : estuary * methane * methane budget * ethane oxidation * River Elbe Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 2.821, year: 2016

  11. Satellite observations of atmospheric methane and their value for quantifying methane emissions

    NARCIS (Netherlands)

    Jacob, Daniel J.; Turner, Alexander J.; Maasakkers, Joannes D.; Sheng, Jianxiong; Sun, Kang; Liu, Xiong; Chance, Kelly; Aben, Ilse; McKeever, Jason; Frankenberg, Christian

    2016-01-01

    Methane is a greenhouse gas emitted by a range of natural and anthropogenic sources. Atmospheric methane has been measured continuously from space since 2003, and new instruments are planned for launch in the near future that will greatly expand the capabilities of space-based observations. We

  12. Gaia's breath - Global methane exhalations

    Science.gov (United States)

    Kvenvolden, K.A.; Rogers, B.W.

    2005-01-01

    Methane (CH4) is the most abundant organic compound in the Earth's atmosphere, where it acts as a greenhouse gas and thus has implications for global climate change. The current atmospheric CH4 budget, however, does not take into account geologically-sourced CH4 seepage. Geological sources of CH4 include natural macro- and micro-seeps, mud volcanoes, and other miscellaneous sources such as gas hydrates, magmatic volcanoes, geothermal regions, and mid-ocean ridges. Macro-seeps contribute ???25 Tg (teragrams) CH4/yr to the atmosphere, whereas, micro-seepage contributes perhaps 7 Tg CH4/yr. Mud volcanoes emit ???5 Tg CH4/yr, and miscellaneous sources emit ???8 Tg CH4/yr to the atmosphere. Thus, the total contribution to the atmosphere from geological sources is estimated to be 45 Tg CH4/yr, which is significant to the atmospheric organic carbon cycle and should be included in any global inventory of atmospheric CH4. We argue that the atmospheric CH4 global inventory of the Interplanetary Panel on Climate Change must be adjusted in order to incorporate geologically-sourced CH4 from naturally occurring seepage.

  13. Rain increases methane production and methane oxidation in a boreal thermokarst bog

    Science.gov (United States)

    Neumann, R. B.; Moorberg, C.; Turner, J.; Wong, A.; Waldrop, M. P.; Euskirchen, E. S.; Edgar, C.; Turetsky, M. R.

    2017-12-01

    Bottom-up biogeochemical models of wetland methane emissions simulate the response of methane production, oxidation and transport to wetland conditions and environmental forcings. One reason for mismatches between bottom-up and top-down estimates of emissions is incomplete knowledge of factors and processes that control microbial rates and methane transport. To advance mechanistic understanding of wetland methane emissions, we conducted a multi-year field investigation and plant manipulation experiment in a thermokarst bog located near Fairbanks, Alaska. The edge of the bog is experiencing active permafrost thaw, while the center of the bog thawed 50 to 100 years ago. Our study, which captured both an average year and two of the wettest years on record, revealed how rain interacts with vascular vegetation and recently thawed permafrost to affect methane emissions. In the floating bog, rain water warmed and oxygenated the subsurface, but did not alter soil saturation. The warmer peat temperatures increased both microbial methane production and plant productivity at the edge of the bog near the actively thawing margin, but minimally altered microbial and plant activity in the center of the bog. These responses indicate processes at the edge of the bog were temperature limited while those in the center were not. The compounding effect of increased microbial activity and plant productivity at the edge of the bog doubled methane emissions from treatments with vascular vegetation during rainy years. In contrast, methane emissions from vegetated treatments in the center of the bog did not change with rain. The oxygenating influence of rain facilitated greater methane oxidation in treatments without vascular vegetation, which offset warming-induced increases in methane production at the edge of the bog and decreased methane emissions in the center of the bog. These results elucidate the complex and spatially variable response of methane production and oxidation in

  14. Multiparametric methane sensor for environmental monitoring

    Science.gov (United States)

    Borecki, M.; Duk, M.; Kociubiński, A.; Korwin-Pawlowski, M. L.

    2016-12-01

    Today, methane sensors find applications mostly in safety alarm installations, gas parameters detection and air pollution classification. Such sensors and sensors elements exists for industry and home use. Under development area of methane sensors application is dedicated to ground gases monitoring. Proper monitoring of soil gases requires reliable and maintenance-free semi-constant and longtime examination at relatively low cost of equipment. The sensors for soil monitoring have to work on soil probe. Therefore, sensor is exposed to environment conditions, as a wide range of temperatures and a full scale of humidity changes, as well as rain, snow and wind, that are not specified for classical methane sensors. Development of such sensor is presented in this paper. The presented sensor construction consists of five commercial non dispersive infra-red (NDIR) methane sensing units, a set of temperature and humidity sensing units, a gas chamber equipped with a micro-fan, automated gas valves and also a microcontroller that controls the measuring procedure. The electronics part of sensor was installed into customized 3D printed housing equipped with self-developed gas valves. The main development of proposed sensor is on the side of experimental evaluation of construction reliability and results of data processing included safety procedures and function for hardware error correction. Redundant methane sensor units are used providing measurement error correction as well as improved measurement accuracy. The humidity and temperature sensors are used for internal compensation of methane measurements as well as for cutting-off the sensor from the environment when the conditions exceed allowable parameters. Results obtained during environment sensing prove that the gas concentration readings are not sensitive to gas chamber vertical or horizontal position. It is important as vertical sensor installation on soil probe is simpler that horizontal one. Data acquired during six

  15. Geologic emissions of methane to the atmosphere.

    Science.gov (United States)

    Etiope, Giuseppe; Klusman, Ronald W

    2002-12-01

    The atmospheric methane budget is commonly defined assuming that major sources derive from the biosphere (wetlands, rice paddies, animals, termites) and that fossil, radiocarbon-free CH4 emission is due to and mediated by anthropogenic activity (natural gas production and distribution, and coal mining). However, the amount of radiocarbon-free CH4 in the atmosphere, estimated at approximately 20% of atmospheric CH4, is higher than the estimates from statistical data of CH4 emission from fossil fuel related anthropogenic sources. This work documents that significant amounts of "old" methane, produced within the Earth crust, can be released naturally into the atmosphere through gas permeable faults and fractured rocks. Major geologic emissions of methane are related to hydrocarbon production in sedimentary basins (biogenic and thermogenic methane) and, subordinately, to inorganic reactions (Fischer-Tropsch type) in geothermal systems. Geologic CH4 emissions include diffuse fluxes over wide areas, or microseepage, on the order of 10(0)-10(2) mg m(-2) day(-1), and localised flows and gas vents, on the order of 10(2) t y(-1), both on land and on the seafloor. Mud volcanoes producing flows of up to 10(3) t y(-1) represent the largest visible expression of geologic methane emission. Several studies have indicated that methanotrophic consumption in soil may be insufficient to consume all leaking geologic CH4 and positive fluxes into the atmosphere can take place in dry or seasonally cold environments. Unsaturated soils have generally been considered a major sink for atmospheric methane, and never a continuous, intermittent, or localised source to the atmosphere. Although geologic CH4 sources need to be quantified more accurately, a preliminary global estimate indicates that there are likely more than enough sources to provide the amount of methane required to account for the suspected missing source of fossil CH4.

  16. Methane converted to low emission energy

    International Nuclear Information System (INIS)

    Kelly, Michael; McLennan, Tim

    2006-01-01

    A new project is underway at a major mine site in China to capture and use waste methane gas from coal mines. The three-year joint project will develop and demonstrate an innovative new Australian technology that captures harmful methane gas from coal mine ventilation air and uses it to produce low emission energy. The project will demonstrate that ventilation air from coal mines, which is largely untapped to date, can be safely captured to provide a source of electricity. An additional benefit of using ventilation air methane from coal mines is an increase in mine safety due to the reduced risk of gas explosions. The project is based on ventilation air methane catalytic combustion gas turbine (VAMCAT) technology. The project will fabricate a prototype demonstration unit and demonstrate the technology in a laboratory in Australia. Once tested in the laboratory the operational performance data and experience obtained will be used to design a 1% I methane turbine for demonstration at Huainan Mine, China. This project will develop technology that uses waste coal mine methane currently vented i into the atmosphere to create electricity and by doing so will reduce greenhouse gas emissions and improve mine safety. Development of this prototype will advance Australia's and China's capacity to reduce the potential greenhouse impact of coal through the development and deployment of VAMCAT technology as a practical solution for mitigating and utilising mine methane to generate power. The project will be implemented by the CSIRO with the Australian Government contributing a grant worth $350 000 to this $1.9 million project. Copyright (2006) Reed Business Information

  17. 76 FR 37641 - Safety Zone; Independence Day Fireworks Celebration for the City of Half Moon Bay, Half Moon Bay, CA

    Science.gov (United States)

    2011-06-28

    ...-AA00 Safety Zone; Independence Day Fireworks Celebration for the City of Half Moon Bay, Half Moon Bay... temporary safety zone in the navigable waters of Half Moon Bay, off of Pillar Point Harbor beach, Half Moon Bay, CA in support of the Independence Day Fireworks Celebration for the City of Half Moon Bay...

  18. Linear dimension reduction and Bayes classification

    Science.gov (United States)

    Decell, H. P., Jr.; Odell, P. L.; Coberly, W. A.

    1978-01-01

    An explicit expression for a compression matrix T of smallest possible left dimension K consistent with preserving the n variate normal Bayes assignment of X to a given one of a finite number of populations and the K variate Bayes assignment of TX to that population was developed. The Bayes population assignment of X and TX were shown to be equivalent for a compression matrix T explicitly calculated as a function of the means and covariances of the given populations.

  19. 78 FR 34575 - Safety Zone; Bay Swim VI, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2013-06-10

    ... 1625-AA00 Safety Zone; Bay Swim VI, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS. ACTION..., Erie, PA. This safety zone is intended to restrict vessels from a portion of Presque Isle bay during... lighthouse dock, Erie, PA. The Captain of the Port Buffalo has determined that this large scale swimming...

  20. 78 FR 45061 - Safety Zone; Sister Bay Marina Fest Fireworks and Ski Show, Sister Bay, WI

    Science.gov (United States)

    2013-07-26

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Sister Bay Marina Fest Fireworks and Ski... intended to restrict vessels from a portion of Sister Bay due to a fireworks display and ski show. This... with the fireworks display and ski show in Sister Bay on August 31, 2013. DATES: This rule is effective...

  1. 77 FR 44140 - Drawbridge Operation Regulation; Sturgeon Bay Ship Canal, Sturgeon Bay, WI

    Science.gov (United States)

    2012-07-27

    ... Maple-Oregon Bridges so vehicular traffic congestion would not develop on downtown Sturgeon Bay streets... movement of vehicular traffic in Sturgeon Bay. The Sturgeon Bay Ship Canal is approximately 8.6 miles long... significant increase in vehicular and vessel traffic during the peak tourist and navigation season between...

  2. 78 FR 29289 - Safety Zone; Big Bay Boom, San Diego Bay, San Diego, CA

    Science.gov (United States)

    2013-05-20

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Big Bay Boom, San Diego Bay, San Diego, CA... establish four temporary safety zones upon the navigable waters of San Diego ] Bay for the Port of San Diego... docket number using any one of the following methods: (1) Federal eRulemaking Portal: http://www...

  3. Atmospheric Methane Growth Anomalies, 2007 - Present

    Science.gov (United States)

    Lowry, D.; Dlugokencky, E. J.; Fisher, R. E.; Nisbet, E. G.; Lanoiselle, M.; France, J.

    2012-12-01

    Several marked growth anomalies in atmospheric methane have occurred since 2007. In particular there has been sustained growth in methane in the Southern Hemisphere. This southern growth anomaly is among the larger excursions in the global methane record so far occurring in the 21st century, yet in contrast to Arctic emission, it has had little attention. The increase in methane began in 2007 and continued through early-2012. In the zonal average from the Equator to 30°S, annual increases reached 7.9 ppb/yr in 2007, remained at 7.0 ppb/yr in 2008, fell to around 2.5 ppb/yr in 2009, then increased to 7.9 ppb/yr in 2010. To consider one specific site, recent data from Ascension Island (which samples South Atlantic air almost exclusively) suggests growth of ~11 ppb/yr from July 2010 to July 2011 (winter to winter) falling to 8 ppb/yr over Jan 2011 - Jan 2012 (summer to summer). Isotopic data for 2011 show 13C enrichments and depletions that may suggest inputs from tropical / subtropical fire and wetland sources, respectively. Despite the size of the southern anomaly, there has been virtually no discussion of its causes. Several possibilities exist: some or all may have occurred: 1) that methane emission from southern wetland (late wet season) and fire (dry season) sources increased sharply during this period; 2) that the southern OH methane sink has decreased; 3) that changes in atmospheric circulation patterns have increased inter-hemispheric transport. It is possible that a major factor was high La Nina rainfall in key areas draining into wetlands in southern tropical Africa and Latin America. Tropical methane sources emit roughly 200 Tg methane annually to the atmosphere, nearly two-fifths of the global budget. Thus changes in tropical sources, if sustained on this scale, can have global significance. However the observational network generally is so sparse in the tropics that identifying causes of methane growth events is more akin to guesswork than evidence

  4. Methane emissions from different coastal wetlands in New England, US

    Science.gov (United States)

    Wang, F.; Tang, J.; Kroeger, K. D.; Gonneea, M. E.

    2017-12-01

    According to the IPCC, methane have 25 times warming effect than CO2, and natural wetlands contribute 20-39 % to the global emission of methane. Although most of these methane was from inland wetlands, there was still large uncertain in the methane emissions in coastal wetlands. In the past three years, we have investigated methane emissions in coastal wetlands in MA, USA. Contrary to previous assumptions, we have observed relative larger methane flux in some salt marshes than freshwater wetlands. We further detect the methane source, and found that plant activities played an important role in methane flux, for example, the growth of S. aterniflora, the dominate plants in salt marsh, could enhance methane emission, while in an fresh water wetland that was dominated by cattail, plant activity oxided methane and reduced total flux. Phragmite, an invasive plant at brackish marsh, have the highest methane flux among all coastal wetland investigated. This study indicated that coastal wetland could still emit relatively high amount of methane even under high water salinity condiations, and plant activity played an important role in methane flux, and this role was highly species-specific.

  5. An Aerial ``Sniffer Dog'' for Methane

    Science.gov (United States)

    Nathan, Brian; Schaefer, Dave; Zondlo, Mark; Khan, Amir; Lary, David

    2012-10-01

    The Earth's surface and its atmosphere maintain a ``Radiation Balance.'' Any factor which influences this balance is labeled as a mechanism of ``Radiative Forcing'' (RF). Greenhouse Gas (GHG) concentrations are among the most important forcing mechanisms. Methane, the second-most-abundant noncondensing greenhouse gas, is over 25 times more effective per molecule at radiating heat than the most abundant, Carbon Dioxide. Methane is also the principal component of Natural Gas, and gas leaks can cause explosions. Additionally, massive quantities of methane reside (in the form of natural gas) in underground shale basins. Recent technological advancements--specifically the combination of horizontal drilling and hydraulic fracturing--have allowed drillers access to portions of these ``plays'' which were previously unreachable, leading to an exponential growth in the shale gas industry. Presently, very little is known about the amount of methane which escapes into the global atmosphere from the extraction process. By using remote-controlled robotic helicopters equipped with specially developed trace gas laser sensors, we can get a 3-D profile of where and how methane is being released into the global atmosphere.

  6. Source Attribution of Methane Emissions in Northeastern Colorado Using Ammonia to Methane Emission Ratios

    Science.gov (United States)

    Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; Perring, A. E.; Robinson, E. S.; Holloway, M.; Trainer, M.

    2015-12-01

    Due to recent advances in extraction technology, oil and natural gas extraction and processing in the Denver-Julesburg basin has increased substantially in the past decade. Northeastern Colorado is also home to over 250 concentrated animal feeding operations (CAFOs), capable of hosting over 2 million head of ruminant livestock (cattle and sheep). Because of methane's high Global Warming Potential, quantification and attribution of methane emissions from oil and gas development and agricultural activity are important for guiding greenhouse gas emission policy. However, due to the co-location of these different sources, top-down measurements of methane are often unable to attribute emissions to a specific source or sector. In this work, we evaluate the ammonia:methane emission ratio directly downwind of CAFOs using a mobile laboratory. Several CAFOs were chosen for periodic study over a 12-month period to identify diurnal and seasonal variation in the emission ratio as well as differences due to livestock type. Using this knowledge of the agricultural ammonia:methane emission ratio, aircraft measurements of ammonia and methane over oil and gas basins in the western US during the Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in March and April 2015 can be used for source attribution of methane emissions.

  7. Simulations of atmospheric methane for Cape Grim, Tasmania, to constrain southeastern Australian methane emissions

    Directory of Open Access Journals (Sweden)

    Z. M. Loh

    2015-01-01

    Full Text Available This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E. The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS and the CSIRO Conformal-Cubic Atmospheric Model (CCAM. Radon is also simulated and used to reduce the impact of transport differences between the models and observations. Comparisons are made for air samples that have traversed the Australian continent. All six emission scenarios give modelled concentrations that are broadly consistent with those observed. There are three notable mismatches, however. Firstly, scenarios that incorporate interannually varying biomass burning emissions produce anomalously high methane concentrations at Cape Grim at times of large fire events in southeastern Australia, most likely due to the fire methane emissions being unrealistically input into the lowest model level. Secondly, scenarios with wetland methane emissions in the austral winter overestimate methane concentrations at Cape Grim during wintertime while scenarios without winter wetland emissions perform better. Finally, all scenarios fail to represent a~methane source in austral spring implied by the observations. It is possible that the timing of wetland emissions in the scenarios is incorrect with recent satellite measurements suggesting an austral spring (September–October–November, rather than winter, maximum for wetland emissions.

  8. Anaerobic methane oxidation rates at the sulfate-methane transition in marine sediments from Kattegat and Skagerrak (Denmark)

    International Nuclear Information System (INIS)

    Iversen, N.; Jorgensen, B.B.

    1985-01-01

    Concomitant radiotracer measurements were made of in situ rates of sulfate reduction and anaerobic methane oxidation in 2-3-m-long sediment cores. Methane accumulated to high concentrations (> 1 mM CH 4 ) only below the sulfate zone, at 1 m or deeper in the sediment. Sulfate reduction showed a broad maximum below the sediment surface and a smaller, narrow maximum at the sulfate-methane transition. Methane oxidation was low (0.002-0.1 nmol CH 4 cm -3 d -1 ) throughout the sulfate zone and showed a sharp maximum at the sulfate-methane transition, coinciding with the sulfate reduction maximum. Total anaerobic methane oxidation at two stations was 0.83 and 1.16 mmol CH 4 m -2 d -1 , of which 96% was confined to the sulfate-methane transition. All the methane that was calculated to diffuse up into the sulfate-methane transition was oxidized in this zone. The methane oxidation was equivalent to 10% of the electron donor requirement for the total measured sulfate reduction. A third station showed high sulfate concentrations at all depths sampled and the total methane oxidation was only 0.013 mmol m -2 d -1 . From direct measurements of rates, concentration gradients, and diffusion coefficients, simple calculations were made of sulfate and methane fluxes and of methane production rates

  9. Methane hydrate in the global organic carbon cycle

    Science.gov (United States)

    Kvenvolden, K.A.

    2002-01-01

    The global occurrence of methane hydrate in outer continental margins and in polar regions, and the magnitude of the amount of methane sequestered in methane hydrate suggest that methane hydrate is an important component in the global organic carbon cycle. Various versions of this cycle have emphasized the importance of methane hydrate, and in the latest version the role of methane hydrate is considered to be analogous to the workings of an electrical circuit. In this circuit the methane hydrate is a condenser and the consequences of methane hydrate dissociation are depicted as a resistor and inductor, reflecting temperature change and changes in earth surface history. These consequences may have implications for global change including global climate change.

  10. A microbial consortium couples anaerobic methane oxidation to denitrification

    NARCIS (Netherlands)

    Raghoebarsing, A.A.; Pol, A.; Pas-Schoonen, K.T. van de; Smolders, A.J.P.; Ettwig, K.F.; Rijpstra, W.I.C.; Schouten, S.; Sinninghe Damsté, J.S.; Camp, H.J.M. op den; Jetten, M.S.M.; Strous, M.

    2006-01-01

    Modern agriculture has accelerated biological methane and nitrogen cycling on a global scale. Freshwater sediments often receive increased downward fluxes of nitrate from agricultural runoff and upward fluxes of methane generated by anaerobic decomposition. In theory, prokaryotes should be

  11. Paradox reconsidered: Methane oversaturation in well-oxygenated lake waters

    DEFF Research Database (Denmark)

    Tang, Kam W.; McGinnis, Daniel F.; Frindte, Katharina

    2014-01-01

    The widely reported paradox of methane oversaturation in oxygenated water challenges the prevailing paradigm that microbial methanogenesis only occurs under anoxic conditions. Using a combination of field sampling, incubation experiments, and modeling, we show that the recurring mid-water methane...... peak in Lake Stechlin, northeast Germany, was not dependent on methane input from the littoral zone or bottom sediment or on the presence of known micro-anoxic zones. The methane peak repeatedly overlapped with oxygen oversaturation in the seasonal thermocline. Incubation experiments and isotope...... analysis indicated active methane production, which was likely linked to photosynthesis and/or nitrogen fixation within the oxygenated water, whereas lessening of methane oxidation by light allowed accumulation of methane in the oxygen-rich upper layer. Estimated methane efflux from the surface water...

  12. Hydrogen Recovery by ECR Plasma Pyrolysis of Methane, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a microgravity and hypogravity compatible microwave plasma methane pyrolysis reactor is proposed to recover hydrogen which is lost as methane in the...

  13. High-pressure oxidation of methane

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Gersen, Sander

    2016-01-01

    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly...... diluted in nitrogen. It was found that under the investigated conditions, the onset temperature for methane oxidation ranged from 723 K under reducing conditions to 750 K under stoichiometric and oxidizing conditions. The RCM experiments were carried out at pressures of 15–80 bar and temperatures of 800......–1250 K under stoichiometric and fuel-lean (Φ=0.5) conditions. Ignition delays, in the range of 1–100 ms, decreased monotonically with increasing pressure and temperature. A chemical kinetic model for high-pressure methane oxidation was established, with particular emphasis on the peroxide chemistry...

  14. Methanization of domestic and industrial wastes

    International Nuclear Information System (INIS)

    2011-01-01

    After having recalled that methanization helps meeting objectives of the Grenelle de l'Environnement regarding waste valorisation and production of renewable heat and electricity, this publication presents the methanization process which produces a humid product (digestate) and biogas by using various wastes (from agriculture, food industry, cities, households, sludge and so on). The numbers of existing and planned methanization units are evoked. The publication discusses the main benefits (production of renewable energy, efficient waste processing, and compact installations), drawbacks (costs, necessary specific abilities, impossibility to treat all organic materials) and associated recommendations. Actions undertaken by the ADEME are evoked. In conclusion, the publication outlines some priorities related to the development of this sector, its benefits, and the main strategic recommendations

  15. Biogas and Methane Yield from Rye Grass

    Directory of Open Access Journals (Sweden)

    Tomáš Vítěz

    2015-01-01

    Full Text Available Biogas production in the Czech Republic has expanded substantially, including marginal regions for maize cultivation. Therefore, there are increasingly sought materials that could partially replace maize silage, as a basic feedstock, while secure both biogas production and its quality.Two samples of rye grass (Lolium multiflorum var. westerwoldicum silage with different solids content 21% and 15% were measured for biogas and methane yield. Rye grass silage with solid content of 15% reached an average specific biogas yield 0.431 m3·kg−1 of organic dry matter and an average specific methane yield 0.249 m3·kg−1 of organic dry matter. Rye grass silage with solid content 21% reached an average specific biogas yield 0.654 m3·kg−1 of organic dry matter and an average specific methane yield 0.399 m3·kg−1 of organic dry matter.

  16. Off limits: sulfate below the sulfate-methane transition

    Directory of Open Access Journals (Sweden)

    Benjamin Brunner

    2016-07-01

    Full Text Available One of the most intriguing recent discoveries in biogeochemistry is the ubiquity of cryptic sulfur cycling. From subglacial lakes to marine oxygen minimum zones, and in marine sediments, cryptic sulfur cycling – the simultaneous sulfate consumption and production – has been observed. Though this process does not leave an imprint in the sulfur budget of the ambient environment – thus the term cryptic – it may have a massive impact on other element cycles and fundamentally change our understanding of biogeochemical processes in the subsurface.Classically, the sulfate-methane transition (SMT in marine sediments is considered to be the boundary that delimits sulfate reduction from methanogenesis as the predominant terminal pathway of organic matter mineralization. Two sediment cores from Aarhus Bay, Denmark reveal the constant presence of sulfate (generally 0.1 to 0.2 mM below the SMT. The sulfur and oxygen isotope signature of this deep sulfate (34S = 18.9‰, 18O = 7.7‰ was close to the isotope signature of bottom-seawater collected from the sampling site (34S = 19.8‰, 18O = 7.3‰. In one of the cores, oxygen isotope values of sulfate at the transition from the base of the SMT to the deep sulfate pool (18O = 4.5‰ to 6.8‰ were distinctly lighter than the deep sulfate pool.Our findings are consistent with a scenario where sulfate enriched in 34S and 18O is removed at the base of the SMT and replaced with isotopically light sulfate below. Here, we explore scenarios that explain this observation, ranging from sampling artifacts, such as contamination with seawater or auto-oxidation of sulfide – to the potential of sulfate generation in a section of the sediment column where sulfate is expected to be absent which enables reductive sulfur cycling, creating the conditions under which sulfate respiration can persist in the methanic zone.

  17. Methane hydrates in nature - Current knowledge and challenges

    Science.gov (United States)

    Collett, Timothy S.

    2014-01-01

    Recognizing the importance of methane hydrate research and the need for a coordinated effort, the United States Congress enacted the Methane Hydrate Research and Development Act of 2000. At the same time, the Ministry of International Trade and Industry in Japan launched a research program to develop plans for a methane hydrate exploratory drilling project in the Nankai Trough. India, China, the Republic of Korea, and other nations also have established large methane hydrate research and development programs. Government-funded scientific research drilling expeditions and production test studies have provided a wealth of information on the occurrence of methane hydrates in nature. Numerous studies have shown that the amount of gas stored as methane hydrates in the world may exceed the volume of known organic carbon sources. However, methane hydrates represent both a scientific and technical challenge, and much remains to be learned about their characteristics and occurrence in nature. Methane hydrate research in recent years has mostly focused on: (1) documenting the geologic parameters that control the occurrence and stability of methane hydrates in nature, (2) assessing the volume of natural gas stored within various methane hydrate accumulations, (3) analyzing the production response and characteristics of methane hydrates, (4) identifying and predicting natural and induced environmental and climate impacts of natural methane hydrates, (5) analyzing the methane hydrate role as a geohazard, (6) establishing the means to detect and characterize methane hydrate accumulations using geologic and geophysical data, and (7) establishing the thermodynamic phase equilibrium properties of methane hydrates as a function of temperature, pressure, and gas composition. The U.S. Department of Energy (DOE) and the Consortium for Ocean Leadership (COL) combined their efforts in 2012 to assess the contributions that scientific drilling has made and could continue to make to advance

  18. Ground and airborne methane measurements with an optical parametric amplifier

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Dawsey, Martha; Ramanathan, Anand; Mao, Jianping; Krainak, Michael; Abshire, James

    2012-06-01

    We report on ground and airborne atmospheric methane measurements with a differential absorption lidar using an optical parametric amplifier (OPA). Methane is a strong greenhouse gas on Earth and its accurate global mapping is urgently needed to understand climate change. We are developing a nanosecond-pulsed OPA for remote measurements of methane from an Earth-orbiting satellite. We have successfully demonstrated the detection of methane on the ground and from an airplane at ~11-km altitude.

  19. Ground and Airborne Methane Measurements with an Optical Parametric Amplifier

    Science.gov (United States)

    Numata, Kenji

    2012-01-01

    We report on ground and airborne atmospheric methane measurements with a differential absorption lidar using an optical parametric amplifier (OPA). Methane is a strong greenhouse gas on Earth and its accurate global mapping is urgently needed to understand climate change. We are developing a nanosecond-pulsed OPA for remote measurements of methane from an Earth-orbiting satellite. We have successfully demonstrated the detection of methane on the ground and from an airplane at approximately 11-km altitude.

  20. Greenhouse Gas Emissions: Quantifying Methane Emissions from Livestock

    OpenAIRE

    Rafiu O. Yusuf; Zainura Z. Noor; Ahmad H. Abba; Mohd Ariffin Abu Hassan; Mohd Fadhil Mohd Din

    2012-01-01

    Problem statement: The rearing of animals for domestic consumption and export invariably lead to the production of methane as a product of digestion. This study investigated the emission of methane from Malaysian livestock between 1980 and 2008. Approach: Seven categories of animals identified were camel, buffalo, sheep, goats, horse, pigs and poultry. The estimation of methane was based on the IPCC Tier 1 and Tier 2 methods. Methane emission from cattle rose by 44% within the period from 45....

  1. Uncertainty assessment of the breath methane concentration method to determine methane production of dairy cows.

    Science.gov (United States)

    Wu, Liansun; Koerkamp, Peter W G Groot; Ogink, Nico

    2018-02-01

    The breath methane concentration method uses the methane concentrations in the cow's breath during feed bin visits as a proxy for the methane production rate. The objective of this study was to assess the uncertainty of a breath methane concentration method in a feeder and its capability to measure and rank cows' methane production. A range of controlled methane fluxes from a so-called artificial reference cow were dosed in a feed bin, and its exhaled air was sampled by a tube inside the feeder and analyzed. The artificial reference cow simulates the lungs, respiratory tract, and rumen of a cow and releases a variable methane flux to generate a concentration pattern in the exhaled breath that closely resembles a real cow's pattern. The strength of the relation between the controlled methane release rates of the artificial reference cow and the measured methane concentrations was analyzed by linear regression, using the coefficient of determination (R 2 ) and the residual standard error as performance indicators. The effect of error sources (source-sampling distance, air turbulence, and cow's head movement) on this relation was experimentally investigated, both under laboratory and barn conditions. From the laboratory to the dairy barn at the 30-cm sampling distance, the R 2 -value decreased from 0.97 to 0.37 and the residual standard error increased from 75 to 86 ppm as a result of barn air turbulence, the latter increasing to a theoretical 94 ppm if modeled variability due to cow's head movement was accounted for as well. In practice, the effect of these random errors can be compensated by sampling strategies including repeated measurements on each cow over time, thus increasing the distinctive power between cows. However, systematic errors that may disturb the relation between concentration and production rate, such as cow variation in air exhalation rate and air flow patterns around sampling locations that differ between barns, cannot be compensated by repeated

  2. Detection of Gaseous Methane on Pluto

    Science.gov (United States)

    Young, Leslie; Tokunaga, Alan; Elliot, J.; deBergh, Catherine; Owen, Tobias; Witteborn, Fred C. (Technical Monitor)

    1995-01-01

    We obtained Pluto's spectrum using the CSHELL echelle spectrograph at NASA's IRTF on Mauna Kea, on 25-26 May 1992, with a spectral resolution of 13,300. The spectral range (5998 - 6018 per centimeter, or 1661.8 - 1666.9 nm) includes the R(0) and the Q(1) - Q(9) lines of the 2v3 band of methane. The resulting spectrum shows the first detection of gaseous methane on Pluto, with a column height of 1.20 (sup +3.15) (sub -0.87) cm-A (3.22 (sup +8.46) (sub -2.34) x 10(exp 19) molecule per square centimeter)).

  3. Morphology of methane hydrate host sediments

    Science.gov (United States)

    Jones, K.W.; Feng, H.; Tomov, S.; Winters, W.J.; Eaton, M.; Mahajan, D.

    2005-01-01

    The morphological features including porosity and grains of methane hydrate host sediments were investigated using synchrotron computed microtomography (CMT) technique. The sediment sample was obtained during Ocean Drilling Program Leg 164 on the Blake Ridge at water depth of 2278.5 m. The CMT experiment was performed at the Brookhaven National Synchrotron Light Source facility. The analysis gave ample porosity, specific surface area, mean particle size, and tortuosity. The method was found to be highly effective for the study of methane hydrate host sediments.

  4. Terrestrial plant methane production and emission

    DEFF Research Database (Denmark)

    Bruhn, Dan; Møller, Ian M.; Mikkelsen, Teis Nørgaard

    2012-01-01

    In this minireview, we evaluate all experimental work published on the phenomenon of aerobic methane (CH4) generation in terrestrial plants and plant. Clearly, despite much uncertainty and skepticism, we conclude that the phenomenon is true. Four stimulating factors have been observed to induce...... aerobic CH4 into a global budget is inadequate. Thus it is too early to draw the line under the aerobic methane emission in plants. Future work is needed for establishing the relative contribution of several proven potential CH4 precursors in plant material....

  5. Methane emissions in Danish riparian wetlands

    DEFF Research Database (Denmark)

    Audet, Joachim; Johansen, Jan Ravn; Andersen, Peter Mejlhede

    2013-01-01

    The present study was conducted to (i) investigate parameters influencing the fluxes of the greenhouse gas methane (CH4) in Danish riparian wetlands with contrasting vegetation characteristics and (ii) develop models relating CH4 emissions to soil and/or vegetation parameters integrating the spat......The present study was conducted to (i) investigate parameters influencing the fluxes of the greenhouse gas methane (CH4) in Danish riparian wetlands with contrasting vegetation characteristics and (ii) develop models relating CH4 emissions to soil and/or vegetation parameters integrating...

  6. Renewable methane from anaerobic digestion of biomass

    International Nuclear Information System (INIS)

    Chynoweth, D.P.; Owens, J.M.

    2001-01-01

    Production of methane via anaerobic digestion of energy crops and organic wastes would benefit society by providing a clean fuel from renewable feedstocks. This would replace fossil fuel-derived energy and reduce environmental impacts including global warming and acid rain. Although biomass energy is more costly than fossil fuel-derived energy, trends to limit carbon dioxide and other emissions through emission regulations, carbon taxes, and subsidies of biomass energy would make it cost competitive. Methane derived from anaerobic digestion is competitive in efficiencies and costs to other biomass energy forms including heat, synthesis gases, and ethanol. (author)

  7. Methane recovery from landfill in China

    Energy Technology Data Exchange (ETDEWEB)

    Gaolai, L.

    1996-12-31

    GEF has approved a special project for a demonstration project for Methane Recovery from the Urban Refuse Land Fill. This paper will introduce the possibility of GHG reduction from the landfill in China, describe the activities of the GEF project, and the priorities for international cooperation in this field. The Global Environment Facility (GEF) approved the project, China Promoting Methane Recovery and Unlization from Mixed Municipal Refuse, at its Council meeting in last April. This project is the first one supported by international organization in this field.

  8. Methanator fueled engines for pollution control

    Science.gov (United States)

    Cagliostro, D. E.; Winkler, E. L.

    1973-01-01

    A methanator fueled Otto-cycle engine is compared with other methods proposed to control pollution due to automobile exhaust emissions. The comparison is made with respect to state of development, emission factors, capital cost, operational and maintenance costs, performance, operational limitations, and impact on the automotive industries. The methanator fueled Otto-cycle engine is projected to meet 1975 emission standards and operate at a lower relative total cost compared to the catalytic muffler system and to have low impact. Additional study is required for system development.

  9. Thermal Conductivity of Methane-Hydrate

    OpenAIRE

    Krivchikov, A. I.; Gorodilov, B. Ya.; Korolyuk, O. A.; Manzhelii, V. G.; Conrad, H.; Press, W.

    2004-01-01

    The thermal conductivity of the methane hydrate CH4 (5.75 H2O) was measured in the interval 2-140 K using the steady-state technique. The thermal conductivity corresponding to a homogeneous substance was calculated from the measured effective thermal conductivity obtained in the experiment. The temperature dependence of the thermal conductivity is typical for the thermal conductivity of amorphous solids. It is shown that after separation of the hydrate into ice and methane, at 240 K, the ther...

  10. Eddy covariance based methane flux in Sundarbans mangroves, India

    Indian Academy of Sciences (India)

    Eddy covariance based methane flux in Sundarbans mangroves, India ... Eddy covariance; mangrove forests; methane flux; Sundarbans. ... In order to quantify the methane flux in mangroves, an eddy covariance flux tower was recently erected in the largest unpolluted and undisturbed mangrove ecosystem in Sundarbans ...

  11. Eddy covariance based methane flux in Sundarbans mangroves, India

    Indian Academy of Sciences (India)

    We report the initial results of the methane flux measured using eddy covariance method during summer months from the world's largest mangrove .... spheric methane with reported methane emissions from different mangrove ecosystems of ... relations with frictional velocity, tidal activity, and soil temperature during summer ...

  12. Effect of weir impoundments on methane dynamics in a river

    Czech Academy of Sciences Publication Activity Database

    Bednařík, A.; Blaser, M.; Matoušů, Anna; Hekera, P.; Rulík, M.

    2017-01-01

    Roč. 584, April (2017), s. 164-174 ISSN 0048-9697 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : methane production * methane emission * methane ebullition * river impoundment * river sediment Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 4.900, year: 2016

  13. Methane production by sheep and cattle in Australia

    Science.gov (United States)

    Minson, D. J.

    1993-02-01

    Using methane production rates from Australian feeds and local estimates of the quantity of feed eaten by different classes of animal, it was estimated that sheep and cattle in Australia produce 2.66 Tg methane in 1990. This value is 43% higher than previous estimates and indicates a need to reassess the methane production of ruminants in other countries.

  14. 30 CFR 57.22226 - Testing for methane (IV mines).

    Science.gov (United States)

    2010-07-01

    ... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22226 Testing for methane (IV mines... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Testing for methane (IV mines). 57.22226 Section 57.22226 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND...

  15. Aquatic herbivores facilitate the emission of methane from wetlands

    NARCIS (Netherlands)

    Dingemans, B.J.J.; Bakker, E.S.; Bodelier, P.L.E.

    2011-01-01

    Wetlands are significant sources of atmospheric methane. Methane produced by microbes enters roots and escapes to the atmosphere through the shoots of emergent wetland plants. Herbivorous birds graze on helophytes, but their effect on methane emission remains unknown. We hypothesized that grazing on

  16. Anaerobic oxidation of methane in coastal sediment from Guishan ...

    Indian Academy of Sciences (India)

    The methane concentration in the pore-water shows dramatic changes and sulfate concentration gradients are linear at the base of the sulfate reduction zone for the station. The carbon isotope of methane becomes heavier at the sulfate-methane transition (SMT)likely because of the Raleigh distillation effect; 12CH4 was ...

  17. Estimating historical landfill quantities to predict methane emissions

    NARCIS (Netherlands)

    Lyons, S.; Murphy, L.; Tol, R.S.J.

    2010-01-01

    There are no observations for methane emissions from landfill waste in Ireland. Methane emissions are imputed from waste data. There are intermittent data on waste sent to landfill. We compare two alternative ways to impute the missing waste " data" and evaluate the impact on methane emissions. We

  18. Methane oxidation coupled to oxygenic photosynthesis in anoxic waters

    Science.gov (United States)

    Milucka, Jana; Kirf, Mathias; Lu, Lu; Krupke, Andreas; Lam, Phyllis; Littmann, Sten; Kuypers, Marcel MM; Schubert, Carsten J

    2015-01-01

    Freshwater lakes represent large methane sources that, in contrast to the Ocean, significantly contribute to non-anthropogenic methane emissions to the atmosphere. Particularly mixed lakes are major methane emitters, while permanently and seasonally stratified lakes with anoxic bottom waters are often characterized by strongly reduced methane emissions. The causes for this reduced methane flux from anoxic lake waters are not fully understood. Here we identified the microorganisms and processes responsible for the near complete consumption of methane in the anoxic waters of a permanently stratified lake, Lago di Cadagno. Interestingly, known anaerobic methanotrophs could not be detected in these waters. Instead, we found abundant gamma-proteobacterial aerobic methane-oxidizing bacteria active in the anoxic waters. In vitro incubations revealed that, among all the tested potential electron acceptors, only the addition of oxygen enhanced the rates of methane oxidation. An equally pronounced stimulation was also observed when the anoxic water samples were incubated in the light. Our combined results from molecular, biogeochemical and single-cell analyses indicate that methane removal at the anoxic chemocline of Lago di Cadagno is due to true aerobic oxidation of methane fuelled by in situ oxygen production by photosynthetic algae. A similar mechanism could be active in seasonally stratified lakes and marine basins such as the Black Sea, where light penetrates to the anoxic chemocline. Given the widespread occurrence of seasonally stratified anoxic lakes, aerobic methane oxidation coupled to oxygenic photosynthesis might have an important but so far neglected role in methane emissions from lakes. PMID:25679533

  19. 30 CFR 77.201 - Methane content in surface installations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Methane content in surface installations. 77.201 Section 77.201 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL... UNDERGROUND COAL MINES Surface Installations § 77.201 Methane content in surface installations. The methane...

  20. The Methanizer : A Small Scale Biogas Reactor for a Restaurant

    NARCIS (Netherlands)

    Vasudevan, R.; Karlsson, O.; Dhejne, K.; Derewonko, P.; Brezet, J.C.

    2010-01-01

    The purpose of this study is to determine the technical and economic feasibility of a smallscale bioreactor called the Methanizer for a restaurant. The bioreactor converts organic waste produced by the restaurant into methane. This methane can be used to power the restaurant’s cooking stoves. The

  1. Hierarchical mixtures of naive Bayes classifiers

    NARCIS (Netherlands)

    Wiering, M.A.

    2002-01-01

    Naive Bayes classifiers tend to perform very well on a large number of problem domains, although their representation power is quite limited compared to more sophisticated machine learning algorithms. In this pa- per we study combining multiple naive Bayes classifiers by using the hierar- chical

  2. Traditional Fisheries of Antongil Bay, Madagascar | Doukakis ...

    African Journals Online (AJOL)

    Madagascar's marine fisheries provide revenue and sustenance for the island nation. Antongil Bay, the largest shallow-water bay along Madagascar's eastern coast, harbors significant marine resources and is heavily utilized by traditional, artisanal (shark-fin) and industrial fisheries. Mean hourly catch rates are just under 1 ...

  3. Guangdong Daya Bay nuclear power station project

    International Nuclear Information System (INIS)

    Zeng Wen Xing

    1994-01-01

    Daya Bay Nuclear Power Station is the largest joint-venture project which is also the largest commercial nuclear power plant currently under construction in China mainland. Organized and executed strictly in accordance with international standards, the Daya Bay project is seen as the first step taken by China in the development programme of large-capacity commercial nuclear power units

  4. Unique thermal record in False Bay

    CSIR Research Space (South Africa)

    Grundlingh, ML

    1993-10-01

    Full Text Available Over the past decade False Bay has assumed a prime position in terms of research in to large South African bays. This is manifested by investigations that cover flow conditions modelling, thermal structure, management, biology and nutrients, geology...

  5. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate

    OpenAIRE

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-01

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential te...

  6. Ruminant Methane δ (13C/12C) - Values: Relation to Atmospheric Methane

    Science.gov (United States)

    Rust, Fleet

    1981-03-01

    The δ (13C/12C) - values of methane produced by fistulated steers, dairy cattle, and wethers, and dairy and beef cattle herds show a bimodal distribution that appears to be correlated with the plant type (C3 or C4, that is, producing either a three- or a four-carbon acid in the first step of photosynthesis) consumed by the animals. These results indicate that cattle and sheep, on a global basis, release methane with an average δ (13C/12C) value of -60 and -63 per mil, respectively. Together they are a source of atmospheric methane whose δ (13C/12C) is similar to published values for marsh gas and cannot explain the 20 per mil higher values for atmospheric methane.

  7. Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake

    DEFF Research Database (Denmark)

    Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin

    2014-01-01

    Anaerobic methane oxidation coupled to denitrification, also known as “nitrate/nitrite-dependent anaerobic methane oxidation” (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments......, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques...... in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were...

  8. Satellite observations of atmospheric methane and their value for quantifying methane emissions

    Directory of Open Access Journals (Sweden)

    D. J. Jacob

    2016-11-01

    Full Text Available Methane is a greenhouse gas emitted by a range of natural and anthropogenic sources. Atmospheric methane has been measured continuously from space since 2003, and new instruments are planned for launch in the near future that will greatly expand the capabilities of space-based observations. We review the value of current, future, and proposed satellite observations to better quantify and understand methane emissions through inverse analyses, from the global scale down to the scale of point sources and in combination with suborbital (surface and aircraft data. Current global observations from Greenhouse Gases Observing Satellite (GOSAT are of high quality but have sparse spatial coverage. They can quantify methane emissions on a regional scale (100–1000 km through multiyear averaging. The Tropospheric Monitoring Instrument (TROPOMI, to be launched in 2017, is expected to quantify daily emissions on the regional scale and will also effectively detect large point sources. A different observing strategy by GHGSat (launched in June 2016 is to target limited viewing domains with very fine pixel resolution in order to detect a wide range of methane point sources. Geostationary observation of methane, still in the proposal stage, will have the unique capability of mapping source regions with high resolution, detecting transient "super-emitter" point sources and resolving diurnal variation of emissions from sources such as wetlands and manure. Exploiting these rapidly expanding satellite measurement capabilities to quantify methane emissions requires a parallel effort to construct high-quality spatially and sectorally resolved emission inventories. Partnership between top-down inverse analyses of atmospheric data and bottom-up construction of emission inventories is crucial to better understanding methane emission processes and subsequently informing climate policy.

  9. Anaerobic methane oxidation coupled to denitrification is the dominant methane sink in a deep lake

    Science.gov (United States)

    Deutzmann, Joerg S.; Stief, Peter; Brandes, Josephin; Schink, Bernhard

    2014-01-01

    Anaerobic methane oxidation coupled to denitrification, also known as “nitrate/nitrite-dependent anaerobic methane oxidation” (n-damo), was discovered in 2006. Since then, only a few studies have identified this process and the associated microorganisms in natural environments. In aquatic sediments, the close proximity of oxygen- and nitrate-consumption zones can mask n-damo as aerobic methane oxidation. We therefore investigated the vertical distribution and the abundance of denitrifying methanotrophs related to Candidatus Methylomirabilis oxyfera with cultivation-independent molecular techniques in the sediments of Lake Constance. Additionally, the vertical distribution of methane oxidation and nitrate consumption zones was inferred from high-resolution microsensor profiles in undisturbed sediment cores. M. oxyfera-like bacteria were virtually absent at shallow-water sites (littoral sediment) and were very abundant at deep-water sites (profundal sediment). In profundal sediment, the vertical distribution of M. oxyfera-like bacteria showed a distinct peak in anoxic layers that coincided with the zone of methane oxidation and nitrate consumption, a strong indication for n-damo carried out by M. oxyfera-like bacteria. Both potential n-damo rates calculated from cell densities (660–4,890 µmol CH4⋅m−2⋅d−1) and actual rates calculated from microsensor profiles (31–437 µmol CH4⋅m−2⋅d−1) were sufficiently high to prevent methane release from profundal sediment solely by this process. Additionally, when nitrate was added to sediment cores exposed to anoxic conditions, the n-damo zone reestablished well below the sediment surface, completely preventing methane release from the sediment. We conclude that the previously overlooked n-damo process can be the major methane sink in stable freshwater environments if nitrate is available in anoxic zones. PMID:25472842

  10. Methane uptake in urban forests and lawns

    Science.gov (United States)

    Peter M. Groffman; Richard V. Pouyat

    2009-01-01

    The largest natural biological sink for the radiatively active trace gas methane (CH4) is bacteria in soils that consume CH4 as an energy and carbon source. This sink has been shown to be sensitive to nitrogen (N) inputs and alterations of soil physical conditions. Given this sensitivity, conversion of native ecosystems to...

  11. A review of the radiolysis of methane

    International Nuclear Information System (INIS)

    Norfolk, D.J.

    1975-08-01

    The review had three objectives: to determine the yields of the primary products and to describe the sequence of reactions in which they take part; to ascertain the effect on these reactions of changes in the physical state of the methane and the quantum energy of the radiation, and of the presence of chemically inert sensitisers; and to identify the situation most similar to the adsorbed phase radiolysis of methane on alumina, and so to predict the likely radiolytic reactions in this system. The main primary product yields in methane gas under γ-irradiation are estimated to be G(CH 4 +) approximately 1.75, G(CH 3 +) approximately 1.46, G(CH 3 ) approximately 1.4 and G(CH 2 ) approximately 1.0. The situation most similar to adsorbed phase radiolysis is inert gas sensitised photolysis at energies below 12.6eV. In this system the major primary process is homolytic dissociation of methane to CH 3 +H. (author)

  12. Aerobic methane production from organic matter

    NARCIS (Netherlands)

    Vigano, I.|info:eu-repo/dai/nl/304831956

    2010-01-01

    Methane, together with H2O, CO2 and N2O, is an important greenhouse gas in the Earth’s atmosphere playing a key role in the radiative budget. It has been known for decades that the production of the reduced compound CH4 is possible almost exclusively in anoxic environments per opera of one of the

  13. DDT in methane-air mixtures

    Science.gov (United States)

    Kuznetsov, M.; Ciccarelli, G.; Dorofeev, S.; Alekseev, V.; Yankin, Yu.; Kim, T. H.

    Experimental results from a study on the critical condition for deflagration-to-detonation transition (DDT) in methane-air mixtures are presented. Experiments were carried out at 293 K and 1 atm using methane-air mixtures with methane concentrations ranging from 5.5 to 17% vol. The tests were performed in detonation tubes with inner-diameters of 174 mm and 520 mm. Detonation cell widths λ were determined in the tests for a range of methane concentrations. The results of DDT tests indicate that for a tube cross-sectional area blockage ratio (BR) of 0.3 the critical condition for DDT can be characterized by the d/λ = 1 criterion. However, for a BR = 0.6 the critical value d/λ was significantly higher. The data also show that the critical condition for DDT can be described by L/λ = 7, where L is the characteristic length-scale of the channel volume between orifice plates. This length-scale is defined by a grouping of the orifice plate dimensions (inner and outer-diameter) and plate spacing.

  14. Biochar effects on methane emissions from soils

    NARCIS (Netherlands)

    Jeffery, Simon; Verheijen, Frank G.A.; Kammann, Claudia; Abalos Rodriguez, Diego

    2016-01-01

    Methane (CH4) emissions have increased by more than 150% since 1750, with agriculture being the major source. Further increases are predicted as permafrost regions start thawing, and rice and ruminant animal production expand. Biochar is posited to increase crop productivity while

  15. Formation and retention of methane in coal

    Energy Technology Data Exchange (ETDEWEB)

    Hucka, V.J.; Bodily, D.M.; Huang, H.

    1992-05-15

    The formation and retention of methane in coalbeds was studied for ten Utah coal samples, one Colorado coal sample and eight coal samples from the Argonne Premium Coal Sample Bank.Methane gas content of the Utah and Colorado coals varied from zero to 9 cm{sup 3}/g. The Utah coals were all high volatile bituminous coals. The Colorado coal was a gassy medium volatile bituminous coal. The Argonne coals cover a range or rank from lignite to low volatile bituminous coal and were used to determine the effect of rank in laboratory studies. The methane content of six selected Utah coal seams and the Colorado coal seam was measured in situ using a special sample collection device and a bubble desorbometer. Coal samples were collected at each measurement site for laboratory analysis. The cleat and joint system was evaluated for the coal and surrounding rocks and geological conditions were noted. Permeability measurements were performed on selected samples and all samples were analyzed for proximate and ultimate analysis, petrographic analysis, {sup 13}C NMR dipolar-dephasing spectroscopy, and density analysis. The observed methane adsorption behavior was correlated with the chemical structure and physical properties of the coals.

  16. Methane rich gasification of wood pellets

    Directory of Open Access Journals (Sweden)

    Joka Magdalena

    2016-01-01

    Full Text Available In the work there are shown the results of experimental studies on methane rich gasification of pinewood pellets in Bio-CONOx technology. The experiment was carried out on a laboratory scale gasifier (5 kW, which design features allow producing a high quality gas with a high methane content. In the results there was identified the impact of the quantity of Bio-CONOx on the amount of flammable gas compounds (methane, hydrogen and carbon monoxide in the synthesis gas and the gas calorific value. The additive was added in 10,20,30 and 50% concentrations to the gasifier chamber. It has been shown that increasing the amount of the additive has a positive effect on the calorific value of the synthesis gas (Fig.1,2. Gas with a high content of methane (and high calorific value was obtained from gasification of biomass with a 50% addition of Bio-CONOx. There was also examined the proportion of blowing air (gasifying medium for which the properties of obtained syngas were the best.

  17. Methane Gas Emissions - is Older Infrastructure Leakier?

    Science.gov (United States)

    Wendt, L. P.; Caulton, D.; Zondlo, M. A.; Lane, H.; Lu, J.; Golston, L.; Pan, D.

    2015-12-01

    Large gains in natural gas production from hydraulic fracturing is reinvigorating the US energy economy. It is a clean burning fuel with lower emissions than that of coal or oil. Studies show that methane (CH4) leaks from natural gas infrastructure vary widely. A broader question is whether leak rates of methane might offset the benefits of combustion of natural gas. Excess methane (CH4) is a major greenhouse gas with a radiative forcing constant of 25 times that of CO2 when projected over a 100-year period. An extensive field study of 250 wells in the Marcellus Shale conducted in July 2015 examined the emission rates of this region and identifed super-emitters. Spud production data will provide information as to whether older infrastructure is responsible for more of the emissions. Quantifying the emission rate was determined by extrapolating methane releases at a distance from private well pads using an inverse Gaussian plume model. Wells studied were selected by prevailing winds, distance from public roads, and topographical information using commercial (ARCGIS and Google Earth), non-profit (drillinginfo), and government (State of PA) databases. Data were collected from the mobile sensing lab (CH4, CO2 and H2O sensors), as well as from a stationary tower. Emission rates from well pads will be compared to their original production (spud dates) to evaluate whether infrastructure age and total production correlates with the observed leak rates. Very preliminary results show no statistical correlation between well pad production rates and observed leak rates.

  18. High-pressure oxidation of methane

    NARCIS (Netherlands)

    Hashemi, Hamid; Christensen, Jakob M.; Gersen, Sander; Levinsky, Howard; Klippenstein, Stephen J.; Glarborg, Peter

    2016-01-01

    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly

  19. Methane oxidation in contrasting soil types

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica; Nielsen, Cecilie Skov; Westergaard-Nielsen, Andreas

    2017-01-01

    Arctic ecosystems are characterized by a wide range of soil moisture conditions and thermal regimes and contribute differently to the net methane (CH4) budget. Yet, it is unclear how climate change will affect the capacity of those systems to act as a net source or sink of CH4. Here, we present r...

  20. Coprecipitated nickel-alumina methanation catalysts

    International Nuclear Information System (INIS)

    Kruissink, E.C.

    1981-01-01

    In the last few years there has been a renewed interest in the methanation reaction CO+3H 2 =CH 4 +H 2 O. The investigations described in this thesis were performed in relation to the application of this reaction, within the framework of the so-called 'NFE' project, also called 'ADAM' and 'EVA' project. This project, which has been under investigation in West Germany for some years, aims at the investigation of the feasibility of transporting heat from a nuclear high temperature reactor by means of a chemical cycle. A promising possibility to realize such a cycle exists in applying the combination of the endothermic steam reforming of methane and the exothermic methanation reaction. This thesis describes the investigations into a certain type of methanation catalyst, viz. a coprecipitated nickel-alumina catalyst, with the aim to give more insight into the interrelationship between the preparation conditions on the one hand and catalyst properties such as activity and stability on the other hand. (Auth.)

  1. Can rapeseed lower methane emission from heifers?

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Sørensen, Martin Tang; Weisbjerg, Martin Riis

    2013-01-01

    Twelve heifers were assigned to either a control diet (CON) with 26 g fat per kg dry matter (DM) or a supplemented diet (FAT) with crushed rapeseed with 53 g fat per kg DM. Methane (CH4) emission was measured by open-circuit indirect calorimetry for four days when the heifers weighed approximately...

  2. Methane emission from tidal freshwater marshes

    NARCIS (Netherlands)

    Van der Nat, F.J.; Middelburg, J.J.

    2000-01-01

    In two tidal freshwater marshes, methane emission, production and accumulation in the pore-water have been studied. The two sites differ in their dominant vegetation, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated in relation to the bulrush site and had

  3. Methane and Root Dynamics in Arctic Soil

    DEFF Research Database (Denmark)

    D'Imperio, Ludovica

    on the global climate. We investigated two aspects of arctic ecosystem dynamics which are not well represented in climatic models: i) soil methane (CH4) oxidation in dry heath tundra and barren soils and ii) root dynamics in wetlands. Field measurements were carried out during the growing season in Disko Island...

  4. Constraining Amazonian Methane Emission from Wetlands

    Science.gov (United States)

    Boesch, Hartmut; Parker, Robert; Webb, Alex; Wilson, Chris; Chipperfield, Martyn; Gloor, Emanuel; Feng, Liang; Palmer, Paul

    2017-04-01

    The Amazon Basin contains large wetland ecosystems which are important sources of methane (CH4). Spaceborne observations provide detailed information about the spatio-temporal distributions of atmospheric methane over the Amazon Basin which will provide a strong constrain on the underlying emissions and their year to year variations. Methane observations from space are available from the Japanese GOSAT instrument since 2009. We use the proxy retrieval method which provides much greater coverage over the Amazon region compared to so-called Full-Physics methods due to their lower sensitivity to thin clouds. Validation of GOSAT retrieval over the Amazon using the ground-based TCCON network is currently not possible due to a lack of data and we have used routine aircraft profiles to show that GOSAT columns are sufficiently accurate for estimating surface flux for the region. Using a variational flux inverse system together with the 3-D atmospheric chemical transport model TOMCAT, we infer surface fluxes for the Amazon region from GOSAT observations which are used to analyse the spatial distribution of methane wetlands emissions as well as annual variations in emissions with a focus on periods 2011/2012 and 2013/14 which are characterized by large variations in rainfall.

  5. Biomass gasification for the production of methane

    NARCIS (Netherlands)

    Nanou, Pavlina

    2013-01-01

    Biomass is very promising as a sustainable alternative to fossil resources because it is a renewable source that contains carbon, an essential building block for gaseous and liquid fuels. Methane is the main component of natural gas, which is a fuel used for heating, power generation and

  6. Biases in methane chamber measurements in peatlands

    Science.gov (United States)

    Juszczak, R.

    2013-03-01

    The paper presents results of CH4 emission measurements at peatland with the application of the dynamic chamber technique. The measurements were conducted in two types of chambers differing in shape, height, volume and technology used to assure their tightness. The study tested how the following factors: 1) forced chamber headspace mixing or its absence, 2) mistakes of the person conducting measurements, 3) improper application of linear technique for calculating CH4 fluxes, and 4) simulated air sampling typical for static chambers, influence the significance of errors and the underestimation rate of CH4 fluxes measured in situ. It was indicated that chamber headspace mixing allows estimating methane fluxes with a smaller error than in the case of measurements conducted without mixing, and CH4 fluxes in such conditions can be 47 to 58% higher (depending on the chamber type) than in a chamber without fans. Using dynamic chambers and a fast analyzer to measure methane fluxes allows shortening the methane measurement process to a few minutes. On the other hand, using static chambers for methane flux measurements may lead to 70% underestimation of the calculated flux.

  7. The global methane budget 2000-2012

    NARCIS (Netherlands)

    Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Brovkin, Victor; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Curry, Charles; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; McDonald, Kyle C.; Marshall, Julia; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans Jan W; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prigent, Catherine; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Steele, Paul; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; Van Weele, Michiel; Van Der Werf, Guido R.; Weiss, Ray; Wiedinmyer, Christine; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

    2016-01-01

    The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of

  8. Market research on biogas valorizations and methanization. Final report

    International Nuclear Information System (INIS)

    2010-09-01

    This market research aims at giving an overview of the existing methanization installations and of their dynamics in France, at assessing biogas production and use, at analyzing the methanization market, and at defining development perspectives for this sector by 2020. Based on a survey of methanization installations, on interviews with many actors of this sector, and on a seminar organized on this topic, this report presents and comments market data for biogas valorization and methanization in different sectors: household, agricultural, and industrial and waste water processing plants. It comments evolution trends by 2020 for these sectors, and the role that the emerging sector of centralized methanization could have in the years to come

  9. Assessing dissolved methane patterns in central New York groundwater

    Directory of Open Access Journals (Sweden)

    Lauren E. McPhillips

    2014-07-01

    New hydrological insights for this region: There was no significant difference between methane concentrations in valleys versus upslope locations, in water wells less than or greater than 1 km from a conventional gas well, and across different geohydrologic units. Methane concentrations were significantly higher in groundwater dominated by sodium chloride or sodium bicarbonate compared with groundwater dominated by calcium bicarbonate, indicating bedrock interactions and lengthy residence times as controls. A multivariate regression model of dissolved methane using only three variables (sodium, hardness, and barium explained 77% of methane variability, further emphasizing the dominance of geochemistry and hydrogeology as controls on baseline methane patterns.

  10. Methane Content Estimation in DuongHuy Coal Mine

    Science.gov (United States)

    Nguyen, Van Thinh; Mijał, Waldemar; Dang, Vu Chi; Nguyen, Thi Tuyet Mai

    2018-03-01

    Methane hazard has always been considered for underground coal mining as it can lead to methane explosion. In Quang Ninh province, several coal mines such as Mạo Khe coal mine, Khe Cham coal mine, especially Duong Huy mine that have high methane content. Experimental data to examine contents of methane bearing coal seams at different depths are not similar in Duong coal mine. In order to ensure safety, this report has been undertaken to determine a pattern of changing methane contents of coal seams at different exploitation depths in Duong Huy underground coal mine.

  11. Methane oxidation in anoxic lake waters

    Science.gov (United States)

    Su, Guangyi; Zopfi, Jakob; Niemann, Helge; Lehmann, Moritz

    2017-04-01

    Freshwater habitats such as lakes are important sources of methante (CH4), however, most studies in lacustrine environments so far provided evidence for aerobic methane oxidation only, and little is known about the importance of anaerobic oxidation of CH4 (AOM) in anoxic lake waters. In marine environments, sulfate reduction coupled to AOM by archaea has been recognized as important sinks of CH4. More recently, the discorvery of anaerobic methane oxidizing denitrifying bacteria represents a novel and possible alternative AOM pathway, involving reactive nitrogen species (e.g., nitrate and nitrite) as electron acceptors in the absence of oxygen. We investigate anaerobic methane oxidation in the water column of two hydrochemically contrasting sites in Lake Lugano, Switzerland. The South Basin displays seasonal stratification, the development of a benthic nepheloid layer and anoxia during summer and fall. The North Basin is permanently stratified with anoxic conditions below 115m water depth. Both Basins accumulate seasonally (South Basin) or permanently (North Basin) large amounts of CH4 in the water column below the chemocline, providing ideal conditions for methanotrophic microorganisms. Previous work revealed a high potential for aerobic methane oxidation within the anoxic water column, but no evidence for true AOM. Here, we show depth distribution data of dissolved CH4, methane oxidation rates and nutrients at both sites. In addition, we performed high resolution phylogenetic analyses of microbial community structures and conducted radio-label incubation experiments with concentrated biomass from anoxic waters and potential alternative electron acceptor additions (nitrate, nitrite and sulfate). First results from the unamended experiments revealed maximum activity of methane oxidation below the redoxcline in both basins. While the incubation experiments neither provided clear evidence for NOx- nor sulfate-dependent AOM, the phylogenetic analysis revealed the

  12. Enhancement of Biogenic Coalbed Methane Production and Back Injection of Coalbed Methane Co-Produced Water

    Energy Technology Data Exchange (ETDEWEB)

    Song Jin

    2007-05-31

    Biogenic methane is a common constituent in deep subsurface environments such as coalbeds and oil shale beds. Coalbed methane (CBM) makes significant contributions to world natural gas industry and CBM production continues to increase. With increasing CBM production, the production of CBM co-produced water increases, which is an environmental concern. This study investigated the feasibility in re-using CBM co-produced water and other high sodic/saline water to enhance biogenic methane production from coal and other unconventional sources, such as oil shale. Microcosms were established with the selected carbon sources which included coal, oil shale, lignite, peat, and diesel-contaminated soil. Each microcosm contained either CBM coproduced water or groundwater with various enhancement and inhibitor combinations. Results indicated that the addition of nutrients and nutrients with additional carbon can enhance biogenic methane production from coal and oil shale. Methane production from oil shale was much greater than that from coal, which is possibly due to the greater amount of available Dissolved Organic Carbon (DOC) from oil shale. Inconclusive results were observed from the other sources since the incubation period was too low. WRI is continuing studies with biogenic methane production from oil shale.

  13. Methane hydrates as potential energy resource: Part 2 - Methane production processes from gas hydrates

    International Nuclear Information System (INIS)

    Demirbas, Ayhan

    2010-01-01

    Three processes have been proposed for dissociation of methane hydrates: thermal stimulation, depressurization, and inhibitor injection. The obvious production approaches involve depressurization, heating and their combinations. The depressurization method is lowering the pressure inside the well and encouraging the methane hydrate to dissociate. Its objective is to lower the pressure in the free-gas zone immediately beneath the hydrate stability zone, causing the hydrate at the base of the hydrate stability zone to decompose. The thermal stimulation method is applied to the hydrate stability zone to raise its temperature, causing the hydrate to decompose. In this method, a source of heat provided directly in the form of injected steam or hot water or another heated liquid, or indirectly via electric or sonic means. This causes methane hydrate to decompose and generates methane gas. The methane gas mixes with the hot water and returns to the surface, where the gas and hot water are separated. The chemical inhibition method seeks to displace the natural-gas hydrate equilibrium condition beyond the hydrate stability zone's thermo-dynamic conditions through injection of a liquid inhibitor chemical adjacent to the hydrate. In this method, inhibitor such as methanol is injected from surface down to methane hydrate-bearing layers. The thermal stimulation method is quite expensive. The chemical inhibitor injection method is also expensive. The depressurization method may prove useful to apply more than one production.

  14. Modelling Holocene carbon accumulation and methane emissions of boreal wetlands – an Earth system model approach

    Directory of Open Access Journals (Sweden)

    R. J. Schuldt

    2013-03-01

    Full Text Available Since the Last Glacial Maximum, boreal wetlands have accumulated substantial amounts of peat, estimated at 180–621 Pg of carbon. Wetlands have significantly affected the atmospheric greenhouse gas composition in the past and will play a significant role in future changes of atmospheric CO2 and CH4 concentrations. In order to investigate those changes with an Earth system model, biogeochemical processes in boreal wetlands need to be accounted for. Thus, a model of peat accumulation and decay was developed and included in the land surface model JSBACH of the Max Planck Institute Earth System Model (MPI-ESM. Here we present the evaluation of model results from 6000 yr BP to the pre-industrial period. Over this period of time, 240 Pg of peat carbon accumulated in the model in the areas north of 40° N. Simulated peat accumulation rates agree well with those reported for boreal wetlands. The model simulates CH4 emissions of 49.3 Tg CH4 yr−1 for 6000 yr BP and 51.5 Tg CH4 yr−1 for pre-industrial times. This is within the range of estimates in the literature, which range from 32 to 112 Tg CH4 yr−1 for boreal wetlands. The modelled methane emission for the West Siberian Lowlands and Hudson Bay Lowlands agree well with observations. The rising trend of methane emissions over the last 6000 yr is in agreement with measurements of Antarctic and Greenland ice cores.

  15. The global methane budget 2000-2012

    Science.gov (United States)

    Saunois, Marielle; Bousquet, Philippe; Poulter, Ben; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; Janssens-Maenhout, Greet; Tubiello, Francesco N.; Castaldi, Simona; Jackson, Robert B.; Alexe, Mihai; Arora, Vivek K.; Beerling, David J.; Bergamaschi, Peter; Blake, Donald R.; Brailsford, Gordon; Brovkin, Victor; Bruhwiler, Lori; Crevoisier, Cyril; Crill, Patrick; Covey, Kristofer; Curry, Charles; Frankenberg, Christian; Gedney, Nicola; Höglund-Isaksson, Lena; Ishizawa, Misa; Ito, Akihiko; Joos, Fortunat; Kim, Heon-Sook; Kleinen, Thomas; Krummel, Paul; Lamarque, Jean-François; Langenfelds, Ray; Locatelli, Robin; Machida, Toshinobu; Maksyutov, Shamil; McDonald, Kyle C.; Marshall, Julia; Melton, Joe R.; Morino, Isamu; Naik, Vaishali; O'Doherty, Simon; Parmentier, Frans-Jan W.; Patra, Prabir K.; Peng, Changhui; Peng, Shushi; Peters, Glen P.; Pison, Isabelle; Prigent, Catherine; Prinn, Ronald; Ramonet, Michel; Riley, William J.; Saito, Makoto; Santini, Monia; Schroeder, Ronny; Simpson, Isobel J.; Spahni, Renato; Steele, Paul; Takizawa, Atsushi; Thornton, Brett F.; Tian, Hanqin; Tohjima, Yasunori; Viovy, Nicolas; Voulgarakis, Apostolos; van Weele, Michiel; van der Werf, Guido R.; Weiss, Ray; Wiedinmyer, Christine; Wilton, David J.; Wiltshire, Andy; Worthy, Doug; Wunch, Debra; Xu, Xiyan; Yoshida, Yukio; Zhang, Bowen; Zhang, Zhen; Zhu, Qiuan

    2016-12-01

    The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (˜ biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 Tg CH4 yr-1, range 540-568. About 60 % of global emissions are anthropogenic (range 50-65 %). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP scenarios

  16. Cryogenic Displacement and Accumulation of Biogenic Methane in Frozen Soils

    Directory of Open Access Journals (Sweden)

    Gleb Kraev

    2017-06-01

    Full Text Available Evidences of highly localized methane fluxes are reported from the Arctic shelf, hot spots of methane emissions in thermokarst lakes, and are believed to evolve to features like Yamal crater on land. The origin of large methane outbursts is problematic. Here we show, that the biogenic methane (13C ≤ −71‰ which formed before and during soil freezing is presently held in the permafrost. Field and experimental observations show that methane tends to accumulate at the permafrost table or in the coarse-grained lithological pockets surrounded by the sediments less-permeable for gas. Our field observations, radiocarbon dating, laboratory tests and theory all suggest that depending on the soil structure and freezing dynamics, this methane may have been displaced downwards tens of meters during freezing and has accumulated in the lithological pockets. The initial flux of methane from the one pocket disclosed by drilling was at a rate of more than 2.5 kg C(CH4 m−2 h−1. The age of the methane was 8–18 thousand years younger than the age of the sediments, suggesting that it was displaced tens of meters during freezing. The theoretical background provided the insight on the cryogenic displacement of methane in support of the field and experimental data. Upon freezing of sediments, methane follows water migration and either dissipates in the freezing soils or concentrates at certain places controlled by the freezing rate, initial methane distribution and soil structure.

  17. Supported Catalysts for CO2 Methanation: A Review

    Directory of Open Access Journals (Sweden)

    Patrizia Frontera

    2017-02-01

    Full Text Available CO2 methanation is a well-known reaction that is of interest as a capture and storage (CCS process and as a renewable energy storage system based on a power-to-gas conversion process by substitute or synthetic natural gas (SNG production. Integrating water electrolysis and CO2 methanation is a highly effective way to store energy produced by renewables sources. The conversion of electricity into methane takes place via two steps: hydrogen is produced by electrolysis and converted to methane by CO2 methanation. The effectiveness and efficiency of power-to-gas plants strongly depend on the CO2 methanation process. For this reason, research on CO2 methanation has intensified over the last 10 years. The rise of active, selective, and stable catalysts is the core of the CO2 methanation process. Novel, heterogeneous catalysts have been tested and tuned such that the CO2 methanation process increases their productivity. The present work aims to give a critical overview of CO2 methanation catalyst production and research carried out in the last 50 years. The fundamentals of reaction mechanism, catalyst deactivation, and catalyst promoters, as well as a discussion of current and future developments in CO2 methanation, are also included.

  18. Could Methane Oxidation in Lakes Be Enhanced by Eutrophication?

    Science.gov (United States)

    Van Grinsven, S.; Villanueva, L.; Harrison, J.; S Sinninghe Damsté, J.

    2017-12-01

    Climate change and eutrophication both affect aquatic ecosystems. Eutrophication is caused by high nutrient inputs, leading to algal blooms, oxygen depletion and disturbances of the natural balances in aquatic systems. Methane, a potent greenhouse gas produced biologically by anaerobic degradation of organic matter, is often released from the sediments of lakes and marine systems to overlying water and the atmosphere. Methane oxidation, a microbial methane consumption process, can limit methane emission from lakes and reservoirs by 50-80%. Here, we studied methane oxidation in a seasonally stratified reservoir: Lacamas Lake in Washington, USA. We found this lake has a large summer storage capacity of methane in its deep water layer, with a very active microbial community capable of oxidizing exceptionally high amounts of methane. The natural presence of terminal electron acceptors is, however, too low to support these high potential rates. Addition of eutrophication-related nutrients such as nitrate and sulfate increased the methane removal rates by 4 to 7-fold. The microbial community was studied using 16S rRNA gene amplicon sequencing and preliminary results indicate the presence of a relatively unknown facultative anaerobic methane oxidizer of the genus Methylomonas, capable of using nitrate as an electron donor. Experiments in which anoxic and oxic conditions were rapidly interchanged showed this facultative anaerobic methane oxidizer has an impressive flexibility towards large, rapid changes in environmental conditions and this feature might be key to the unexpectedly high methane removal rates in eutrophied and anoxic watersheds.

  19. Using Methane Absorption to Probe Jupiter's Atmosphere

    Science.gov (United States)

    1997-01-01

    Mosaics of a belt-zone boundary near Jupiter's equator in near-infrared light moderately absorbed by atmospheric methane (top panel), and strongly absorbed by atmospheric methane (bottom panel). The four images that make up each of these mosaics were taken within a few minutes of each other. Methane in Jupiter's atmosphere absorbs light at specific wavelengths called absorption bands. By detecting light close and far from these absorption bands, Galileo can probe to different depths in Jupiter's atmosphere. Sunlight near 732 nanometers (top panel) is moderately absorbed by methane. Some of the light reflected from clouds deep in Jupiter's troposphere is absorbed, enhancing the higher features. Sunlight at 886 nanometers (bottom panel) is strongly absorbed by methane. Most of the light reflected from the deeper clouds is absorbed, making these clouds invisible. Features in the diffuse cloud layer higher in Jupiter's atmosphere are greatly enhanced.North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  20. Methane, Ethane, and Nitrogen Stability on Titan

    Science.gov (United States)

    Hanley, J.; Grundy, W. M.; Thompson, G.; Dustrud, S.; Pearce, L.; Lindberg, G.; Roe, H. G.; Tegler, S.

    2017-12-01

    Many outer solar system bodies are likely to have a combination of methane, ethane and nitrogen. In particular the lakes of Titan are known to consist of these species. Understanding the past and current stability of these lakes requires characterizing the interactions of methane and ethane, along with nitrogen, as both liquids and ices. Our cryogenic laboratory setup allows us to explore ices down to 30 K through imaging, and transmission and Raman spectroscopy. Our recent work has shown that although methane and ethane have similar freezing points, when mixed they can remain liquid down to 72 K. Concurrently with the freezing point measurements we acquire transmission or Raman spectra of these mixtures to understand how the structural features change with concentration and temperature. Any mixing of these two species together will depress the freezing point of the lake below Titan's surface temperature, preventing them from freezing. We will present new results utilizing our recently acquired Raman spectrometer that allow us to explore both the liquid and solid phases of the ternary system of methane, ethane and nitrogen. In particular we will explore the effect of nitrogen on the eutectic of the methane-ethane system. At high pressure we find that the ternary creates two separate liquid phases. Through spectroscopy we determined the bottom layer to be nitrogen rich, and the top layer to be ethane rich. Identifying the eutectic, as well as understanding the liquidus and solidus points of combinations of these species, has implications for not only the lakes on the surface of Titan, but also for the evaporation/condensation/cloud cycle in the atmosphere, as well as the stability of these species on other outer solar system bodies. These results will help interpretation of future observational data, and guide current theoretical models.

  1. SAES St 909 pilot scale methane cracking tests

    International Nuclear Information System (INIS)

    Klein, J. E.; Sessions, H. T.

    2008-01-01

    Pilot scale (0.5 kg) SAES St 909 methane cracking tests were conducted for potential tritium process applications. Up to 1400 hours tests were done at 700 deg.C, 202.7 kPa (1520 torr) with a 0.03 sLPM feed of methane plus impurities, in a 20 vol% hydrogen, balance helium, stream. Carbon dioxide gettered by St 909 can be equated to an equivalent amount of methane gettered, but equating nitrogen to an equivalent amount of methane was nitrogen feed composition dependent. A decreased hydrogen feed increased methane getter rates while a 30 deg.C drop in one furnace zone increased methane emissions by over a factor of 30. The impact of gettered nitrogen can be somewhat minimized if nitrogen feed to the bed has been stopped and sufficient time given to recover the methane cracking rate. (authors)

  2. Energy sector methane recovery and use: the importance of policy

    Energy Technology Data Exchange (ETDEWEB)

    Tom Kerr; Michelle Hershman

    2009-08-15

    To raise awareness about appropriate policy options to advance methane recovery and use in the energy sector, the IEA has conducted a series of analyses and studies over the past few years. This report continues IEA efforts by providing policy makers with examples and best practices in methane mitigation policy design and implementation. This report offers an overview of four types of methane mitigation projects that have the strongest links to the energy sector: oil and gas methane recovery and reduction of leaks and losses; coal mine methane; landfill methane; and manure methane recovery and use. It identifies successful policies that have been used to advance these important projects. This information is intended to guide policy makers as they search for low-cost, near-term solutions to climate change. 38 refs., 10 figs., 1 app.

  3. Estimating methane emissions from mangrove area in Ranong Province, Thailand

    Directory of Open Access Journals (Sweden)

    Suwanchai Nitisoravut

    2005-01-01

    Full Text Available This study aimed to estimate methane emissions from the mangrove area of Ranong Province andto explore the factors affecting the emissions, as part of an attempt to evaluate methane contribution to the global methane budget. Methane was measured by using a closed chamber technique and analyzed by a gas chromatograph equipped with a flame ionization detector (FID. The results showed that the annual estimated methane emission was released at approximately 157.32 mg/m2. The amount of methane emission from this mangrove area was lower than in other previously studied areas. Emission rates varied seasonally with the highest rate in the rainy season followed by summer and cold seasons, during which the values were 0.52, 0.27, and 0.19 mg/m2/day, respectively. Seasonal variations of methane emission was related to several factors depending upon field conditions such as water conductivity, soil temperature, and water level.

  4. Comparison of forest area data in the Chesapeake Bay Watershed

    Science.gov (United States)

    Tonya W. Lister; Andrew J. Lister

    2012-01-01

    The Chesapeake Bay, the largest estuary in the United States, has been designated by executive order as a national treasure. There is much interest in monitoring the status and trends in forest area within the bay, especially since maintaining forest cover is key to bay restoration efforts. The Chesapeake Bay Land Cover Data Series (CBLCD), a Landsat-based, multi-...

  5. Microbial methane oxidation processes and technologies for mitigation of landfill gas emissions

    DEFF Research Database (Denmark)

    Scheutz, Charlotte; Kjeldsen, Peter; Bogner, J.E.

    2009-01-01

    Landfill gas containing methane is produced by anaerobic degradation of organic waste. Methane is a strong greenhouse gas and landfills are one of the major anthropogenic sources of atmospheric methane. Landfill methane may be oxidized by methanotrophic microorganisms in soils or waste materials...... to predict methane emissions from landfills. Additional research and technology development is needed before methane mitigation technologies utilizing microbial methane oxidation processes can become commercially viable and widely deployed....

  6. THz identification and Bayes modeling

    Science.gov (United States)

    Sokolnikov, Andre

    2017-05-01

    THz Identification is a developing technology. Sensing in the THz range potentially gives opportunity for short range radar sensing because THz waves can better penetrate through obscured atmosphere, such as fog, than visible light. The lower scattering of THz as opposed to the visible light results also in significantly better imaging than in IR spectrum. A much higher contrast can be achieved in medical trans-illumination applications than with X-rays or visible light. The same THz radiation qualities produce better tomographical images from hard surfaces, e.g. ceramics. This effect comes from the delay in time of reflected THz pulses detection. For special or commercial applications alike, the industrial quality control of defects is facilitated with a lower cost. The effectiveness of THz wave measurements is increased with computational methods. One of them is Bayes modeling. Examples of this kind of mathematical modeling are considered.

  7. The Liverpool Bay Coastal Observatory

    Science.gov (United States)

    Howarth, Michael John; O'Neill, Clare K.; Palmer, Matthew R.

    2010-05-01

    A pre-operational Coastal Observatory has been functioning since August 2002 in Liverpool Bay, Irish Sea. Its rationale is to develop the science underpinning the ecosystem based approach to marine management, including distinguishing between natural and man-made variability, with particular emphasis on eutrophication and predicting responses of a coastal sea to climate change. Liverpool Bay has strong tidal mixing, receives fresh water principally from the Dee, Mersey and Ribble estuaries, each with different catchment influences, and has enhanced levels of nutrients. Horizontal and vertical density gradients are variable both in space and time. The challenge is to understand and model accurately this variable region which is turbulent, turbid, receives enhanced nutrients and is productive. The Observatory has three components, for each of which the goal is some (near) real-time operation - measurements; coupled 3-D hydrodynamic, wave and ecological models; a data management and web-based data delivery system which provides free access to the data, http://cobs.pol.ac.uk. The integrated measurements are designed to test numerical models and have as a major objective obtaining multi-year records, covering tidal, event (storm / calm / bloom), seasonal and interannual time scales. The four main strands on different complementary space or time scales are:- a) fixed point time series (in situ and shore-based); very good temporal and very poor spatial resolution. These include tide gauges; a meteorological station on Hilbre Island at the mouth of the Dee; two in situ sites, one by the Mersey Bar, measuring waves and the vertical structure of current, temperature and salinity. A CEFAS SmartBuoy whose measurements include surface nutrients is deployed at the Mersey Bar site. b) regular (nine times per year) spatial water column surveys on a 9 km grid; good vertical resolution for some variables, limited spatial coverage and resolution, and limited temporal resolution. The

  8. A pollution history of Chesapeake Bay

    Science.gov (United States)

    Goldberg, E.D.; Hodge, V.; Koide, M.; Griffin, J.; Gamble, E.; Bricker, O.P.; Matisoff, G.; Holdren, G.R.; Braun, R.

    1978-01-01

    Present day anthropogenic fluxes of some heavy metals to central Chesapeake Bay appear to be intermediate to those of the southern California coastal region and those of Narragansett Bay. The natural fluxes, however, are in general higher. On the bases of Pb-210 and Pu-239 + 240 geochronologies and of the time changes in interstitial water compositions, there is a mixing of the upper 30 or so centimeters of the sediments in the mid-Chesapeake Bay area through bioturbation by burrowing mollusks and polychaetes. Coal, coke and charcoal levels reach one percent or more by dry weight in the deposits, primarily as a consequence of coal mining operations. ?? 1978.

  9. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island...

  10. 78 FR 62293 - Safety Zone, Oyster Festival 30th Anniversary Fireworks Display, Oyster Bay; Oyster Bay, NY

    Science.gov (United States)

    2013-10-15

    ... Safety Zone, Oyster Festival 30th Anniversary Fireworks Display, Oyster Bay; Oyster Bay, NY AGENCY: Coast... zone on the navigable waters of Oyster Bay near Oyster Bay, NY for the Oyster Festival 30th Anniversary... Oyster Festival 30th Anniversary Fireworks Display is scheduled for October 19, 2013 and is one of...

  11. Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget. Final report, 1 January-30 June 1991

    International Nuclear Information System (INIS)

    Wahlen, M.

    1994-03-01

    The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany

  12. Coalbed methane: from hazard to resource

    Science.gov (United States)

    Flores, R.M.

    1998-01-01

    Coalbed gas, which mainly consists of methane, has remained a major hazard affecting safety and productivity in underground coal mines for more than 100 yr. Coalbed gas emissions have resulted in outbursts and explosions where ignited by open lights, smoking or improper use of black blasting powder, and machinery operations. Investigations of coal gas outbursts and explosions during the past century were aimed at predicting and preventing this mine hazard. During this time, gas emissions were diluted with ventilation by airways (eg, tunnels, vertical and horizontal drillholes, shsfts) and by drainage boreholes. The 1970s 'energy crisis' led to studies of the feasibility of producing the gas for commercial use. Subsequent research on the origin, accumulation, distribution, availability, and recoverability has been pursued vigorously during the past two decades. Since the 1970s research investigations on the causes and effects of coal mine outbursts and gas emissions have led to major advances towards the recovery and development of coalbed methane for commercial use. Thus, coalbed methane as a mining hazard was harnessed as a conventional gas resource.Coalbed gas, which mainly consists of methane, has remained a major hazard affecting safety and productivity in underground coal mines for more than 100 years. Coalbed gas emissions have resulted in outbursts and explosions where ignited by open lights, smoking or improper use of black blasting powder, and machinery operations. Investigations of coal gas outbursts and explosions during the past century were aimed at predicting and preventing this mine hazard. During this time, gas emissions were diluted with ventilation by airways (e.g., tunnels, vertical and horizontal drillholes, shafts) and by drainage boreholes. The 1970's `energy crisis' led to studies of the feasibility of producing the gas for commercial use. Subsequent research on the origin, accumulation, distribution, availability, and recoverability has been

  13. Description of gravity cores from San Pablo Bay and Carquinez Strait, San Francisco Bay, California

    Science.gov (United States)

    Woodrow, Donald L.; John L. Chin,; Wong, Florence L.; Fregoso, Theresa; Jaffe, Bruce E.

    2017-06-27

    Seventy-two gravity cores were collected by the U.S. Geological Survey in 1990, 1991, and 2000 from San Pablo Bay and Carquinez Strait, California. The gravity cores collected within San Pablo Bay contain bioturbated laminated silts and sandy clays, whole and broken bivalve shells (mostly mussels), fossil tube structures, and fine-grained plant or wood fragments. Gravity cores from the channel wall of Carquinez Strait east of San Pablo Bay consist of sand and clay layers, whole and broken bivalve shells (less than in San Pablo Bay), trace fossil tubes, and minute fragments of plant material.

  14. Sea Ice - The overlooked Player in the Arctic Methane Cycle

    Science.gov (United States)

    Damm, E.

    2017-12-01

    Methane is a greenhouse gas and increasing atmospheric concentrations contribute to trigger global warming. The Arctic hosts large natural methane sources and is expected to be a region where warming feeds warming, i.e. temperature changes may quickly induce enhanced methane emissions. This Arctic amplification of global warming has led to increased summer sea ice retreat, thinning sea ice and decreasing multiyear and increasing one-year sea ice. Hence as feedback to a feedback, sea ice loss will have until now unforeseen consequences for methane efflux while as well as sea ice-ocean interactions and shelf-ocean links have to be taken into account. I will present an overview of multiple direct and indirect effects of sea ice on the marine methane cycle not yet counted. Arctic shelf water is reported to be methane super-saturated in summer. Hence an important interaction between sea ice and methane is to be expected when sea ice formation on shelves induces super-saturated brine which will be enclosed in sea ice during winter and released in spring during melt. It will be shown that especially Polynya regions allow studying the effect of strong ice formation in winter which generate deep convection and resuspension of sediments with subsequent methane release. Once released, then methane may either directly escape to the atmosphere or remain trapped in sea ice. The further fate of the enclosed methane is closely coupled to the fate of the sea ice. Hence thinning and shifts in sea ice-age will be pivotal for methane cycling. Sea ice drift may transport shelf- released methane to remote locations in the interior Arctic where the cascade of freezing and melting events triggers the level of super-saturation in Polar surface water below. To date these kinds of sea ice-ocean interaction processes initially induced by shelf-released methane are the most unknown boxes in calculating the methane budget. Considering these pathways instead of efflux estimations calculated by

  15. Removal of methane from compressed natural gas fueled vehicle exhaust

    International Nuclear Information System (INIS)

    Subramanian, S.; Kudla, R.J.; Chattha, M.S.

    1992-01-01

    The objective of this paper is to investigate the modes of methane (CH 4 ) removal from simulated compressed natural gas (CNG) fueled vehicle exhaust under net oxidizing, net reducing, and stoichiometric conditions. Model reaction studies were conducted. The results suggest that the oxidation of methane with oxygen contributes to the removal of methane under net oxidizing conditions. In contrast, the oxidation of methane with oxygen as well as nitric oxide contributes to its removal under net reducing conditions. The steam reforming reaction does not significantly contribute to the removal of methane. The methane conversions under net reducing conditions are higher than those observed under net oxidizing conditions. The study shows that the presence of carbon monoxide in the feed gas leads to a gradual decrease in the methane conversion with increasing redox ratio, under net oxidizing conditions. a minimum in methane conversion is observed at a redox ratio of 0. 8. The higher activity for the methane-oxygen reaction resulting from a lowering in the overall oxidation state of palladium and the contribution of the methane-nitric oxide reaction toward the removal of CH 4 appear to account for the higher CH 4 conversions observed under net reducing conditions

  16. Methane splitting in the K plant at Heydebreck

    Energy Technology Data Exchange (ETDEWEB)

    1942-03-09

    This report consisted of two major topics. The first was methane splitting in equipment for gas for distant transmission. The amount to be split was 3500 m/sup 3//hr methane per system. The temperature in the converter outlet was 850/sup 0/C and the methane was preheated to 650/sup 0/C. The results of this showed oxygen requirements to be 0.487 m/sup 3//m/sup 3/ of methane, steam requirements to be 0.529 kg/m/sup 3/ of methane, condensate requirements to be 0.518 kg/m/sup 3/ of methane, and cooling-water requirements to be 16 kg/m/sup 3/ of methane. The second topic was methane splitting in equipment for long-distance gas with additional indirect cooling. A summary showed the oxygen requirements to be 0.487 m/sup 3//m/sup 3/ of methane, steam requirements to be 0.107 kg/m/sup 3/ of methane, condensate requirements to be 0.526 kg/m/sup 3/ of methane, and cooling-water requirements to be 9.6 kg/m/sup 3/ of methane. The items discussed for each topic included calculations of methane converters, which included oxygen requirements and a heat balance of the converter; cooling of the split gas, which included heat content of the split gas at the catalyst converter outlet and heat exchangers; and the cooler-vaporizer system, which included a heat balance of the water circuit, determination of the amount of water in the cooler-vaporizer, and final cooling. 3 figures.

  17. Willapa Bay, Washington Benthic Habitats 1995 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  18. Willapa Bay, Washington Benthic Habitats 1995 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  19. Willapa Bay, Washington Benthic Habitats 1995 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  20. Delaware River and Upper Bay Sediment Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The area of coverage consists of 192 square miles of benthic habitat mapped from 2005 to 2007 in the Delaware River and Upper Delaware Bay. The bottom sediment map...

  1. Underwater Grass Comeback Helps Chesapeake Bay

    Science.gov (United States)

    The fortified Susquehanna Flats, the largest bed of underwater grasses in the Chesapeake Bay, seems able to withstand a major weather punch. Its resilience is contributing to an overall increase in the Bay’s submerged aquatic vegetation.

  2. San Antonio Bay 1986-1989

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The effect of salinity on utilization of shallow-water nursery habitats by aquatic fauna was assessed in San Antonio Bay, Texas. Overall, 272 samples were collected...

  3. BENTHIC MACROFAUNAL ALIENS IN WILLAPA BAY

    Science.gov (United States)

    Benthic macrofaunal samples were collected at random stations in Willapa Bay, WA, in four habitats [eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), ghost shrimp (Neotrypaea californiensis)] in 1996 and in seven habitats (Z...

  4. Biscayne Bay Florida Bottlenose Dolphin Studies

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets include a compilation of small vessel based studies of bottlenose dolphins that reside within Biscayne Bay, Florida, adjacent estuaries and nearshore...

  5. FL BAY SPECTROUT-POPULATION STATUS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile spotted seatrout and other sportfish are being monitored annually over a 6-mo period in Florida Bay to assess their abundance over time relative to...

  6. Chesapeake Bay Watershed Implementation Plans (WIPs)

    Science.gov (United States)

    This page provides an overview of Watershed Implementation Plans (WIP) and how they play an important role in restoring the Chesapeake Bay. The page also provides links to each jurisdiction's Phase I, II, and III WIP.

  7. Searching for ?13 at Daya Bay

    International Nuclear Information System (INIS)

    Giedt, Joel; Napolitano, James

    2015-01-01

    An experiment has been carried out by the Daya Bay Collaboration to measure the neutrino mixing angle θ 13 . In addition, the grant has supported research into lattice field theory beyond the standard model.

  8. Corpus ChristiEast Matagorda Bay 1986

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Patterns of habitat utilization were compared among transplanted and natural Spartina alterniflora marshes in the Halls Lake area of Chocolate Bay in the Galveston...

  9. Mesozoic anomalies in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Ramana, M.V.; Nair, R.R.; Sarma, K.V.L.N.S.; Ramprasad, T.; Krishna, K.S.; Subrahmanyam, V.; D'Cruz, M.; Subrahmanyam, C.; Paul, J.; Subrahmanyam, A.S.; Sekhar, D.V.C.

    The analysis of 8200 line km of total magnetic intensity data in the Bay of Bengal, northeastern Indian Ocean, revealed the presence of approximately N30~'E-trending seafloor spreading type magnetic anomalies. These anomalies resemble the Mesozoic...

  10. San Francisco Bay Interferometric Bathymetry: Area B

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — High resolution sonar data were collected over ultra-shallow areas of the San Francisco Bay estuary system. Bathymetric and acoustic backscatter data were collected...

  11. Methane, where does it come from and what is its impact on climate?

    International Nuclear Information System (INIS)

    Andre, Jean-Claude; Boucher, Olivier; Bousquet, Philippe; Chanin, Marie-Lise; Chappellaz, Jerome; Tardieu, Bernard; Denegre, Jean; Beauvais, Muriel; Lefaudeux, Francois; Appert, Olivier; Desmarest, Patrice; Feillet, Pierre; Jarry, Bruno; Minster, Jean-Francois; Masson-Delmotte, Valerie; Dessus, Benjamin; Le Treut, Herve

    2013-01-01

    This report proposes a detailed presentation of knowledge on methane and on its role in the atmosphere. The first part addresses methane and the greenhouse effect: general considerations on methane in the atmosphere, radiative properties and importance with respect to the greenhouse effect, methane and future climate change. The second part proposes a presentation of methane sources and sinks. The third part addresses the study of methane fluxes: possible approaches to assess methane fluxes, measurement of atmospheric methane, the issue of atmospheric inversion (an approach to convert atmospheric observations into methane fluxes, lessons learned from atmospheric inversions, perspectives to improve knowledge on methane fluxes). The next chapters discuss the past, present and future evolution of methane in the atmosphere, discuss the carbon equivalence of methane (Kyoto protocol, policies of climate change, global warming power, role of methane, metrics, emission reduction), and comment the current perceivable evolutions, propose some methodological recommendations and actions to be implemented on the short term with no regret

  12. Chesapeake Bay Low Freshwater Inflow Study.

    Science.gov (United States)

    1984-09-01

    canvasback, redhead , lows: Bay for long periods, but eventually mi- ringneck, and scaup, winter through- grate to their ocean spawning grounds out Chesapeake...Basin -’ The economic and demographic pro- jections prepared by the Department of Figure II-1 1 Economic A reas - ChesapeakeBayDrainageBasin Commerce...for many of the waterfowl that cannot be replaced by high salinity SAV. The Biota Evaluation Panel has . estimated that redhead ducks would . decline

  13. Methane production from acid hydrolysates of Agave tequilana bagasse: evaluation of hydrolysis conditions and methane yield.

    Science.gov (United States)

    Arreola-Vargas, Jorge; Ojeda-Castillo, Valeria; Snell-Castro, Raúl; Corona-González, Rosa Isela; Alatriste-Mondragón, Felipe; Méndez-Acosta, Hugo O

    2015-04-01

    Evaluation of diluted acid hydrolysis for sugar extraction from cooked and uncooked Agave tequilana bagasse and feasibility of using the hydrolysates as substrate for methane production, with and without nutrient addition, in anaerobic sequencing batch reactors (AnSBR) were studied. Results showed that the hydrolysis over the cooked bagasse was more effective for sugar extraction at the studied conditions. Total sugars concentration in the cooked and uncooked bagasse hydrolysates were 27.9 g/L and 18.7 g/L, respectively. However, 5-hydroxymethylfurfural was detected in the cooked bagasse hydrolysate, and therefore, the uncooked bagasse hydrolysate was selected as substrate for methane production. Interestingly, results showed that the AnSBR operated without nutrient addition obtained a constant methane production (0.26 L CH4/g COD), whereas the AnSBR operated with nutrient addition presented a gradual methane suppression. Molecular analyses suggested that methane suppression in the experiment with nutrient addition was due to a negative effect over the archaeal/bacterial ratio. Copyright © 2015. Published by Elsevier Ltd.

  14. Methane bubble ascent within muddy aquatic sediments under different ambient methane source strengths

    Science.gov (United States)

    Tarboush Sirhan, Shahrazad; Katsman, Regina; Ten Brink, Uri

    2016-04-01

    Methane (CH4) is the simplest and, the most common hydrocarbon in nature. It is considered as one of the most adverse greenhouse gases, at least 25 times more potent than carbon dioxide. When concentration of the dissolved methane in pore waters exceeds the solubility of the gas (affected in turn by temperature, pressure, salinity and by other factors) methane bubbles nucleate. Gas migration in fine-grained cohesive muddy aquatic sediments is accompanied by sediment fracturing. When gas pressure is high enough to overcome compression, friction, and cohesion at grain contacts, gas migrates by pushing the grains apart. These sub-vertical fractures provide lowered-resistance conduits for migration of other bubbles that can destabilize sediment structure resulting even in slope failure. Therefore, understanding the processes governing bubble propagation within fine-grained aquatic sediment is important. Previous models showed that bubbles propagation within fine-grained muddy aquatic sediments can be modeled using principles of linear elastic fracture mechanics. Mass transfer between the bubble rising with high velocity and the surrounding sediments was mostly ignored. We use a coupled macroscopic mechanical/reaction-transport numerical model under a variable source strength profile associated with bio-chemical processes of methane production and consumption within the sediment, as it occurs in nature. The model shows that changes in the dissolved methane concentrations strongly affect bubble ascent velocity, sometimes leading to its retardation below the sediment-water interface

  15. Influence of headspace pressure on methane production in Biochemical Methane Potential (BMP) tests.

    Science.gov (United States)

    Valero, David; Montes, Jesús A; Rico, José Luis; Rico, Carlos

    2016-02-01

    The biochemical methane potential test is the most commonly applied method to determine methane production from organic wastes. One of the parameters measured is the volume of biogas produced which can be determined manometrically by keeping the volume constant and measuring increases in pressure. In the present study, the effect of pressure accumulation in the headspace of the reactors has been studied. Triplicate batch trials employing cocoa shell, waste coffee grounds and dairy manure as substrates have been performed under two headspace pressure conditions. The results obtained in the study showed that headspace overpressures higher than 600mbar affected methane production for waste coffee grounds. On the contrary, headspace overpressures within a range of 600-1000mbar did not affect methane production for cocoa shell and dairy manure. With the analyses performed in the present work it has not been possible to determine the reasons for the lower methane yield value obtained for the waste coffee grounds under high headspace pressures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Dams release methane even in temperate zoned

    International Nuclear Information System (INIS)

    Lemarchand, F.

    2010-01-01

    The Wohlen lake (near Bern) is a retaining dam built 90 years ago that has undergone a campaign to measure the quantity of methane released. The campaign lasted 1 year and the result was unexpected: 0.15 g/m 2 *day which one of the highest release rates in temperate zones. This result is all the more stunning since water stays only 2 days in average in the reservoir and that the drowned area is not important. In fact the river Aar that feeds the lake is loaded with organic matter coming from humane activities: agriculture and 3 sewage plants. This organic matter decays in the lake releasing methane. (A.C.)

  17. Regulation of methane genes and genome expression

    Energy Technology Data Exchange (ETDEWEB)

    John N. Reeve

    2009-09-09

    At the start of this project, it was known that methanogens were Archaeabacteria (now Archaea) and were therefore predicted to have gene expression and regulatory systems different from Bacteria, but few of the molecular biology details were established. The goals were then to establish the structures and organizations of genes in methanogens, and to develop the genetic technologies needed to investigate and dissect methanogen gene expression and regulation in vivo. By cloning and sequencing, we established the gene and operon structures of all of the “methane” genes that encode the enzymes that catalyze methane biosynthesis from carbon dioxide and hydrogen. This work identified unique sequences in the methane gene that we designated mcrA, that encodes the largest subunit of methyl-coenzyme M reductase, that could be used to identify methanogen DNA and establish methanogen phylogenetic relationships. McrA sequences are now the accepted standard and used extensively as hybridization probes to identify and quantify methanogens in environmental research. With the methane genes in hand, we used northern blot and then later whole-genome microarray hybridization analyses to establish how growth phase and substrate availability regulated methane gene expression in Methanobacterium thermautotrophicus ΔH (now Methanothermobacter thermautotrophicus). Isoenzymes or pairs of functionally equivalent enzymes catalyze several steps in the hydrogen-dependent reduction of carbon dioxide to methane. We established that hydrogen availability determine which of these pairs of methane genes is expressed and therefore which of the alternative enzymes is employed to catalyze methane biosynthesis under different environmental conditions. As were unable to establish a reliable genetic system for M. thermautotrophicus, we developed in vitro transcription as an alternative system to investigate methanogen gene expression and regulation. This led to the discovery that an archaeal protein

  18. Glacial Cycles Influence Marine Methane Hydrate Formation

    Science.gov (United States)

    Malinverno, A.; Cook, A. E.; Daigle, H.; Oryan, B.

    2018-01-01

    Methane hydrates in fine-grained continental slope sediments often occupy isolated depth intervals surrounded by hydrate-free sediments. As they are not connected to deep gas sources, these hydrate deposits have been interpreted as sourced by in situ microbial methane. We investigate here the hypothesis that these isolated hydrate accumulations form preferentially in sediments deposited during Pleistocene glacial lowstands that contain relatively large amounts of labile particulate organic carbon, leading to enhanced microbial methanogenesis. To test this hypothesis, we apply an advection-diffusion-reaction model with a time-dependent organic carbon deposition controlled by glacioeustatic sea level variations. In the model, hydrate forms in sediments with greater organic carbon content deposited during the penultimate glacial cycle ( 120-240 ka). The model predictions match hydrate-bearing intervals detected in three sites drilled on the northern Gulf of Mexico continental slope, supporting the hypothesis of hydrate formation driven by enhanced organic carbon burial during glacial lowstands.

  19. Guide of good practices for methanization projects

    International Nuclear Information System (INIS)

    Delatte, Constant; Orozco-Souel, Paola; Rouxel, Anaick; Tanneau, Patrick; Schreiber, Konrad; Jaubert, Jean Noel; Micone, Philippe; Dionne, Denis; Renner, Christophe; Ollivier, Denis

    2011-12-01

    This guide aims at providing project holders with guidance on factors which may influence social acceptability of methanization projects and with recommendations regarding communication and dialogue for a better project integration, with a technical support in order to guarantee project quality for a minimised environmental impact, and at convincing and reassuring local communities which plan to implement a methanization project, notably with respect to issues like odours, safety or landscape integration. The guide first outlines the importance of a serious and credible approach, and aims project holders at demonstrating an actual reasonable economic control of energy, environmental and social issues related to their project. The second part proposes technical solutions regarding the limitation of impact on air quality, preservation and restoration of soil quality and water resources, landscape integration, transport management and noise prevention. Feedbacks on experiences with different types of installations (agricultural, industrial, and so on) are also provided. A good practice charter is finally proposed

  20. Methanization - how to better figure out profitability

    International Nuclear Information System (INIS)

    Deschaseaux, Christelle

    2013-01-01

    This article discusses the content of a study to be published on the conditions of profitability for methanization installations, in order to enable the assessment of the influence of the modifications of different parameters such as purchase tariffs, subsidies, taxes, investment management and exploitation costs. An analysis has been performed on different categories of projects: farm projects (80 to 250 kW), collective farm projects with a small collective dwelling (350 kW) and local projects (1 to 2,5 MW), hybrid farm-industrial projects, and projects based only on industrial wastes. The analysis has been made with respect to final use: co-generation or bio-methane production. It appears that most of projects still need subsidies but that there is no correlation between installed power and production cost

  1. Nitrogen as a regulatory factor of methane oxidation in soils and sediments

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Laanbroek, H.J.

    2004-01-01

    The oxidation of methane by methane-oxidising microorganisms is an important link in the global methane budget. Oxic soils are a net sink while wetland soils are a net source of atmospheric methane. It has generally been accepted that the consumption of methane in upland as well as lowland systems

  2. Salting-out of methane in the aqueous solutions of urea and sarcosine

    Indian Academy of Sciences (India)

    Methane-methane potentials of mean force (PMFs) were then calculated in other works using the Monte Carlo algorithm16,17 in infinitely dilute systems with two methane molecules. Dang et al.18 performed one of the first molecu- lar dynamics simulations to calculate methane-methane. PMFs in water, in good agreement ...

  3. Are elusive anaerobic pathways key methane sinks in eutrophic lakes and reservoirs?

    NARCIS (Netherlands)

    Reed, D.C.; Deemer, B.R.; van Grinsven, S.; Harrison, J.A.

    2017-01-01

    Collectively, freshwaters constitute a significant source of methane to the atmosphere, and both methane production and methane oxidation can strongly influence net emissions. Anaerobic methane oxidation (AOM) is recognized as a strong regulator of marine methane emissions and appreciation of AOM’s

  4. Activation of Methane by Gaseous Metal Ions

    Czech Academy of Sciences Publication Activity Database

    Schröder, Detlef

    2010-01-01

    Roč. 49, č. 5 (2010), s. 850-851 ISSN 1433-7851 Grant - others:European Research Council(XE) AdG HORIZOMS Institutional research plan: CEZ:AV0Z40550506 Keywords : C-C coupling * C-H bond activation * gas-phase reactions * metal ions * methane Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.730, year: 2010

  5. The White Paper on bio-methane

    International Nuclear Information System (INIS)

    Saint Jouan, Cedric de

    2016-01-01

    After a presentation of the France Biomethane think tank, this publication indicates its main proposals for the development of the bio-methane sector. Then, it details these proposals which are classified under three main axes: to facilitate the procurement of administrative authorisations and plant exploitation, to strengthen the confidence of financial actors in order to facilitate the achievement of installations, and to promote the use of biomethane as biofuel

  6. Cross Sections for Electron Collisions with Methane

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mi-Young, E-mail: mysong@nfri.re.kr; Yoon, Jung-Sik [Plasma Technology Research Center, National Fusion Research Institute, 814-2 Osikdo-dong, Gunsan, Jeollabuk-do 573-540 (Korea, Republic of); Cho, Hyuck [Department of Physics, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Itikawa, Yukikazu [Institute of Space and Astronautical Science, Sagamihara 252-5210 (Japan); Karwasz, Grzegorz P. [Faculty of Physics, Astronomy and Applied Informatics, University Nicolaus Copernicus, Grudziadzka 5, 87100 Toruń (Poland); Kokoouline, Viatcheslav [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Nakamura, Yoshiharu [6-1-5-201 Miyazaki, Miyamae, Kawasaki 216-0033 (Japan); Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-06-15

    Cross section data are compiled from the literature for electron collisions with methane (CH{sub 4}) molecules. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, dissociation, ionization, and dissociative attachment. The data derived from swarm experiments are also considered. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed through early 2014.

  7. TITAN'S TRANSPORT-DRIVEN METHANE CYCLE

    International Nuclear Information System (INIS)

    Mitchell, Jonathan L.

    2012-01-01

    The mechanisms behind the occurrence of large cloud outbursts and precipitation on Titan have been disputed. A global- and annual-mean estimate of surface fluxes indicated only 1% of the insolation, or ∼0.04 W m –2 , is exchanged as sensible and/or latent fluxes. Since these fluxes are responsible for driving atmospheric convection, it has been argued that moist convection should be quite rare and precipitation even rarer, even if evaporation globally dominates the surface-atmosphere energy exchange. In contrast, climate simulations indicate substantial cloud formation and/or precipitation. We argue that the top-of-atmosphere (TOA) radiative imbalance is diagnostic of horizontal heat transport by Titan's atmosphere, and thus constrains the strength of the methane cycle. Simple calculations show the TOA radiative imbalance is ∼0.5-1 W m –2 in Titan's equatorial region, which implies 2-3 MW of latitudinal heat transport by the atmosphere. Our simulation of Titan's climate suggests this transport may occur primarily as latent heat, with net evaporation at the equator and net accumulation at higher latitudes. Thus, the methane cycle could be 10-20 times previous estimates. Opposing seasonal transport at solstices, compensation by sensible heat transport, and focusing of precipitation by large-scale dynamics could further enhance the local, instantaneous strength of Titan's methane cycle by a factor of several. A limited supply of surface liquids in regions of large surface radiative imbalance may throttle the methane cycle, and if so, we predict more frequent large storms over the lakes district during Titan's northern summer.

  8. Thermal Conversion of Methane to Acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Fincke, James Russell; Anderson, Raymond Paul; Hyde, Timothy Allen; Wright, Randy Ben; Bewley, Randy Lee; Haggard, Delon C; Swank, William David

    2000-01-01

    This report describes the experimental demonstration of a process for the direct thermal conversion of methane to acetylene. The process utilizes a thermal plasma heat source to dissociation products react to form a mixture of acetylene and hydrogen. The use of a supersonic expansion of the hot gas is investigated as a method of rapidly cooling (quenching) the product stream to prevent further reaction or thermal decomposition of the acetylene which can lower the overall efficiency of the process.

  9. The structure of deuterated methane-hydrate

    Science.gov (United States)

    Gutt, C.; Asmussen, B.; Press, W.; Johnson, M. R.; Handa, Y. P.; Tse, J. S.

    2000-09-01

    We present the results of a high-resolution neutron diffraction experiment with a fully deuterated methane hydrate type I at temperatures of 2, 100, and 150 K. Precise crystallographic parameters of the ice-like D2O lattice and the thermal parameters of the encaged methane molecules have been obtained. The parameters of the host lattice differ only slightly from values found for hydrates with asymmetric guests included, which leads to the conclusion that the host lattice of structure I is only a little adaptive. At low temperatures (2 K) the methane molecules in both types of cages present in structure I occupy positions in the center of the cages. At higher temperatures the thermal parameters in both types of cages reflect the surrounding cage geometries or more precisely the translational potentials of the cages. The orientational scattering length density of the CD4 molecules has been analyzed in terms of a multipole expansion with symmetry adapted functions [Press and Hüller, Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. A29, 252 (1972); Press, ibid. A29, 257 (1972)]. In both types of cages we found only small modulations of a spherically symmetric scattering density accounting for almost free rotations of the methane molecules. The large and asymmetric cage leads to a somewhat more pronounced modulation of the orientational density than in the small dodecahedral cage. The orientational probability distribution function (PDF) remains nearly unchanged from 2 to 150 K. At 200 K we observed the time-resolved decomposition of the hydrate structure I into hexagonal ice Ih.

  10. CONTINUOUSLY WORKING SCREW METHANE-TANK

    Directory of Open Access Journals (Sweden)

    S. Shamanskyi

    2013-07-01

    Full Text Available Advantages and disadvantages of conventional anaerobic digester (methane-tank constructions, which are in use for sewage water sediments neutralization, were examined in this article. A new continuously working construction of the device was proposed that is based on modern conceptions about fermentation processes. It‘s principle of operation takes into consideration results of previous researches. It was shown that the device allows to reduce fermentation time significantly and to improve sanitary and hygienic characteristics of the neutralized sediment

  11. Deriving Chesapeake Bay Water Quality Standards

    Science.gov (United States)

    Tango, Peter J.; Batiuk, Richard A.

    2013-01-01

    Achieving and maintaining the water quality conditions necessary to protect the aquatic living resources of the Chesapeake Bay and its tidal tributaries has required a foundation of quantifiable water quality criteria. Quantitative criteria serve as a critical basis for assessing the attainment of designated uses and measuring progress toward meeting water quality goals of the Chesapeake Bay Program partnership. In 1987, the Chesapeake Bay Program partnership committed to defining the water quality conditions necessary to protect aquatic living resources. Under section 303(c) of the Clean Water Act, States and authorized tribes have the primary responsibility for adopting water quality standards into law or regulation. The Chesapeake Bay Program partnership worked with U.S. Environmental Protection Agency to develop and publish a guidance framework of ambient water quality criteria with designated uses and assessment procedures for dissolved oxygen, water clarity, and chlorophyll a for Chesapeake Bay and its tidal tributaries in 2003. This article reviews the derivation of the water quality criteria, criteria assessment protocols, designated use boundaries, and their refinements published in six addendum documents since 2003 and successfully adopted into each jurisdiction's water quality standards used in developing the Chesapeake Bay Total Maximum Daily Load.

  12. Gradient Analysis and Classification of Carolina Bay Vegetation: A Framework for Bay Wetlands Conservation and Restoration

    Energy Technology Data Exchange (ETDEWEB)

    Diane De Steven,Ph.D.; Maureen Tone,PhD.

    1997-10-01

    This report address four project objectives: (1) Gradient model of Carolina bay vegetation on the SRS--The authors use ordination analyses to identify environmental and landscape factors that are correlated with vegetation composition. Significant factors can provide a framework for site-based conservation of existing diversity, and they may also be useful site predictors for potential vegetation in bay restorations. (2) Regional analysis of Carolina bay vegetation diversity--They expand the ordination analyses to assess the degree to which SRS bays encompass the range of vegetation diversity found in the regional landscape of South Carolina's western Upper Coastal Plain. Such comparisons can indicate floristic status relative to regional potentials and identify missing species or community elements that might be re-introduced or restored. (3) Classification of vegetation communities in Upper Coastal Plain bays--They use cluster analysis to identify plant community-types at the regional scale, and explore how this classification may be functional with respect to significant environmental and landscape factors. An environmentally-based classification at the whole-bay level can provide a system of templates for managing bays as individual units and for restoring bays to desired plant communities. (4) Qualitative model for bay vegetation dynamics--They analyze present-day vegetation in relation to historic land uses and disturbances. The distinctive history of SRS bays provides the possibility of assessing pathways of post-disturbance succession. They attempt to develop a coarse-scale model of vegetation shifts in response to changing site factors; such qualitative models can provide a basis for suggesting management interventions that may be needed to maintain desired vegetation in protected or restored bays.

  13. Seasonal total methane depletion in limestone caves.

    Science.gov (United States)

    Waring, Chris L; Hankin, Stuart I; Griffith, David W T; Kertesz, Michael A; Kobylski, Victoria; Wilson, Neil L; Coleman, Nicholas V; Kettlewell, Graham; Zlot, Robert; Bosse, Michael; Bell, Graham

    2017-08-16

    Methane concentration in caves is commonly much lower than the external atmosphere, yet the cave CH 4 depletion causal mechanism is contested and dynamic links to external diurnal and seasonal temperature cycles unknown. Here, we report a continuous 3-year record of cave methane and other trace gases in Jenolan Caves, Australia which shows a seasonal cycle of extreme CH 4 depletion, from ambient ~1,775 ppb to near zero during summer and to ~800 ppb in winter. Methanotrophic bacteria, some newly-discovered, rapidly consume methane on cave surfaces and in external karst soils with lifetimes in the cave of a few hours. Extreme bacterial selection due to the absence of alternate carbon sources for growth in the cave environment has resulted in an extremely high proportion 2-12% of methanotrophs in the total bacteria present. Unexpected seasonal bias in our cave CH 4 depletion record is explained by a three-step process involving methanotrophy in aerobic karst soil above the cave, summer transport of soil-gas into the cave through epikarst, followed by further cave CH 4 depletion. Disentangling cause and effect of cave gas variations by tracing sources and sinks has identified seasonal speleothem growth bias, with implied palaeo-climate record bias.

  14. Aerobic methane production from organic matter

    Science.gov (United States)

    Vigano, I.

    2010-01-01

    Methane, together with H2O, CO2 and N2O, is an important greenhouse gas in th e Earth’s atmosphere playing a key role in the radiative budget. It has be en known for decades that the production of the reduced compound CH4 is possible almost exclusively in anoxic environments per opera of one of the most importan t class of microorganisms which form the Archaea reign. Methane can be produced also from incomplete combustion of organic material. The generation of CH4 in an oxygenated environment under near-ambient conditions is a new discovery made in 2006 by Keppler et. al where surprisingly they measured emissions of this green house gas from plants incubated in chambers with air containing 20% of oxygen. A lthough the estimates on a global scale are still object of an intensive debate, the results presented in this thesis clearly show the existence of methane prod uction under oxic conditions for non living plant material. Temperature and UV l ight are key factors that drive the generation of CH4 from plant matter in a wel l oxygenated environment.

  15. Transcontinental Surface Validation of Satellite Observations of Enhanced Methane Anomalies Associated with Fossil Fuel Industrial Methane Emissions

    Science.gov (United States)

    Leifer, I.; Culling, D.; Schneising, O.; Bovensmann, H.; Buchwitz, M.; Burrows, J. P.

    2012-12-01

    A ground-based, transcontinental (Florida to California - i.e., satellite-scale) survey was conducted to understand better the role of fossil fuel industrial (FFI) fugitive emissions of the potent greenhouse gas, methane. Data were collected by flame ion detection gas chromatography (Fall 2010) and by a cavity ring-down sensor (Winter 2012) from a nearly continuously moving recreational vehicle, allowing 24/7 data collection. Nocturnal methane measurements for similar sources tended to be higher compared to daytime values, sometime significantly, due to day/night meteorological differences. Data revealed strong and persistent FFI methane sources associated with refining, a presumed major pipeline leak, and several minor pipeline leaks, a coal loading plant, and areas of active petroleum production. Data showed FFI source emissions were highly transient and heterogeneous; however, integrated over these large-scale facilities, methane signatures overwhelmed that of other sources, creating clearly identifiable plumes that were well elevated above ambient. The highest methane concentration recorded was 39 ppm at an active central valley California production field, while desert values were as low as 1.80 ppm. Surface methane data show similar trends with strong emissions correlated with FFI on large (4° bin) scales and positive methane anomalies centered on the Gulf Coast area of Houston, home to most of US refining capacity. Comparison with SCIAMACHY and GOSAT satellite data show agreement with surface data in the large-scale methane spatial patterns. Positive satellite methane anomalies in the southeast and Mexico largely correlated with methane anthropogenic and wetland inventory models suggests most strong ground methane anomalies in the Gulf of Mexico region were related to dominant FFI input for most seasons. Wind advection played a role, in some cases confounding a clear relationship. Results are consistent with a non-negligible underestimation of the FFI

  16. Potential for biohydrogen and methane production from olive pulp

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Skiadas, Ioannis V.; Ahring, Birgitte Kiær

    2005-01-01

    The present study investigates the potential for thermophilic biohydrogen and methane production from olive pulp, which is the semi-solid residue coming from the two-phase processing of olives. It focussed on: a) production of methane from the raw olive pulp, b) anaerobic bio-production of hydrogen...... from the olive pulp, and c) subsequent anaerobic treatment of the hydrogen-effluent with the simultaneous production of methane. Both continuous and batch experiments were performed. The hydrogen potential of the olive pulp amounted to 1.6 mmole H-2 per g TS. The methane potential of the raw olive pulp...... and hydrogen-effluent was as high as 19 mmole CH4 per g TS. This suggests that olive pulp is an ideal substrate for methane production and it shows that biohydrogen production can be very efficiently coupled with a subsequent step for methane production....

  17. methanization of organic matters. Guide for project developers

    International Nuclear Information System (INIS)

    2015-02-01

    This document aims at informing potential project developers (farmers, local communities, industrials) all along the creation of a methanization unit. It precisely indicates administrative procedures required to complete a project. It first presents some generalities about methanization (matters and their performance, methanization cycle, biogas), describes methanization processes (dry and humid), and valorisation processes (co-generation, hot water production, gas injection into the public network), presents digestate characteristics, and discusses benefits and drawbacks of methanization. The different steps of a project management are then analysed. Additional procedures are indicated, and risks and traps of methanization projects are highlighted. The document comes along with a large number of appendices which can be documents released by professional or public bodies

  18. Martian Methane From a Cometary Source: A Hypothesis

    Science.gov (United States)

    Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.; hide

    2016-01-01

    In recent years, methane in the martian atmosphere has been detected by Earth-based spectroscopy, the Planetary Fourier Spectrometer on the ESA Mars Express mission, and the NASA Mars Science Laboratory. The methane's origin remains a mystery, with proposed sources including volcanism, exogenous sources like impacts and interplanetary dust, aqueous alteration of olivine in the presence of carbonaceous material, release from ancient deposits of methane clathrates, and/or biological activity. An additional potential source exists: meteor showers from the emission of large comet dust particles could generate martian methane via UV pyrolysis of carbon-rich infall material. We find a correlation between the dates of Mars/cometary orbit encounters and detections of methane on Mars. We hypothesize that cometary debris falls onto Mars during these interactions, generating methane via UV photolysis.

  19. Methane to bioproducts: the future of the bioeconomy?

    Science.gov (United States)

    Pieja, Allison J; Morse, Molly C; Cal, Andrew J

    2017-12-01

    Methanotrophs have been studied since the 1970s, but interest has increased tremendously in recent years due to their potential to transform methane into valuable bioproducts. The vast quantity of available methane and the low price of methane as natural gas have helped to spur this interest. The most well-studied, biologically-derived products from methane include methanol, polyhydroxyalkanoates, and single cell protein. However, many other high-interest chemicals such as biofuels or high-value products such as ectoine could be made industrially relevant through metabolic engineering. Although challenges must be overcome to achieve commercialization of biologically manufactured methane-to-products, taking a holistic view of the production process or radically re-imagining pathways could lead to a future bioeconomy with methane as the primary feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Oxygenation of methane by methane-grown Pseudomonas methanica and Methanomonas methanooxidans.

    Science.gov (United States)

    Higgins, I J; Quayle, J R

    1970-06-01

    1. Experimental conditions have been found in which small amounts of methanol (approximately 2.5mm) accumulated when washed cell suspensions of methane-grown Pseudomonas methanica and Methanomonas methanooxidans were incubated with methane+oxygen mixtures in Warburg flasks. 2. The methanol formed could be separated completely from water by fractional distillation through glass helices followed by gas chromatography using 20% polyethylene glycol 400 on a Celite 545 support. 3. By using (18)O-enriched oxygen gas the abundance of (18)O in the methanol formed from oxidation of methane was measured with a Perkin-Elmer 270 combined gas chromatograph/mass spectrometer. The results showed that the oxygen in methanol was derived exclusively from gaseous oxygen in both micro-organisms. 4. Control experiments using [(18)O]water in incubation mixtures confirmed that there was negligible incorporation of the oxygen atom from water into methanol.

  1. Plasma catalytic process for CO2 methanation

    International Nuclear Information System (INIS)

    Nizio, Magdalena

    2016-01-01

    The limited resources of oil and natural gas, together with an increasing energy demand, forces us to seek more and more efficient and cleaner energy production alternatives. Hydrogen has been recently considered as a promising energy carrier. However, there are several inherent problems to the utilization of H 2 , from its transportation to its distribution. Transformation of the H 2 molecule by fixing into a carbon-containing compound, i.e. CH 4 , will offer the possibility of using the conventional transportation network. Indeed, the Sabatier reaction, which is highly exothermic, involves the reaction of carbon dioxide and hydrogen gas in order to produce methane and water. This process, called methanation, represents a feasible approach contributing to the reduction of the CO 2 emissions in our atmosphere, through a closed carbon cycle involving the valorization of CO 2 , i.e. from capture. However, below a temperature of 250 C, the conversion becomes practically close to 0 %, whereas at higher temperatures, i.e., (≥300 C), the co-existence of secondary reactions favours the formation of CO and H 2 . This is the reason why new catalysts and process conditions are continuously being investigated in order to maximize the methane selectivity at low reaction temperatures at atmospheric pressure. Therefore, by using catalysts combined to Dielectric Barrier Discharge plasmas (DBD), the activation of the methanation reaction can be enhanced and overcome the drawbacks of existing conventional processes. Several Ni-containing catalysts were prepared using various ceria-zirconia oxides as supports, with different Ce/Zr ratios. The results obtained in the adiabatic conditions at low temperatures (ranging between 100-150 C), in the presence of catalysts activated by plasma, are promising. Indeed, the conversion of CO 2 to CH 4 is about 85 % with a selectivity close to 100 %. The same conversion in the absence of the plasma activation of the catalyst is observed at 350 C

  2. Modeling sulfate reduction in methane hydrate-bearing continental margin sediments: Does a sulfate-methane transition require anaerobic oxidation of methane?

    Science.gov (United States)

    Malinverno, A.; Pohlman, J.W.

    2011-01-01

    The sulfate-methane transition (SMT), a biogeochemical zone where sulfate and methane are metabolized, is commonly observed at shallow depths (1-30 mbsf) in methane-bearing marine sediments. Two processes consume sulfate at and above the SMT, anaerobic oxidation of methane (AOM) and organoclastic sulfate reduction (OSR). Differentiating the relative contribution of each process is critical to estimate methane flux into the SMT, which, in turn, is necessary to predict deeper occurrences of gas hydrates in continental margin sediments. To evaluate the relative importance of these two sulfate reduction pathways, we developed a diagenetic model to compute the pore water concentrations of sulfate, methane, and dissolved inorganic carbon (DIC). By separately tracking DIC containing 12C and 13C, the model also computes ??13C-DIC values. The model reproduces common observations from methane-rich sediments: a well-defined SMT with no methane above and no sulfate below and a ??13C-DIC minimum at the SMT. The model also highlights the role of upward diffusing 13C-enriched DIC in contributing to the carbon isotope mass balance of DIC. A combination of OSR and AOM, each consuming similar amounts of sulfate, matches observations from Site U1325 (Integrated Ocean Drilling Program Expedition 311, northern Cascadia margin). Without AOM, methane diffuses above the SMT, which contradicts existing field data. The modeling results are generalized with a dimensional analysis to the range of SMT depths and sedimentation rates typical of continental margins. The modeling shows that AOM must be active to establish an SMT wherein methane is quantitatively consumed and the ??13C-DIC minimum occurs. The presence of an SMT generally requires active AOM. Copyright 2011 by the American Geophysical Union.

  3. Estimating Historical Landfill Quantities to Predict Methane Emissions

    OpenAIRE

    Lyons, Seán; Murphy, Liam; Tol, Richard S. J.

    2009-01-01

    We estimate Irish historical landfill quantities from 1960 -2008 and Irish methane emissions from 1968-2006. A model is constructed in which waste generation is a function of income, price of waste disposal and, household economies of scale. A transformation ratio of waste to methane is also included in the methane emissions model. Our results contrast significantly with the Irish Environmental Protection Agency's (EPA) figures due to the differences in the underlying assumptions. The EPA's w...

  4. Estimating Historical Landfill Quantities to Predict Methane Emissions

    OpenAIRE

    LYONS, SEAN; TOL, RICHARD

    2009-01-01

    PUBLISHED We estimate Irish historical landfill quantities from 1960 -2008 and Irish methane emissions from 1968-2006. A model is constructed in which waste generation is a function of income, price of waste disposal and, household economies of scale. A transformation ratio of waste to methane is also included in the methane emissions model. Our results contrast significantly with the Irish Environmental Protection Agency's (EPA) figures due to the differences in the underlying assumptions...

  5. Estimation of Methane from Hydrocarbon Exploration and Production in India

    OpenAIRE

    A. K. Pathak; K. Ojha

    2012-01-01

    Methane is the second most important greenhouse gas (GHG) after carbon dioxide. Amount of methane emission from energy sector is increasing day by day with various activities. In present work, various sources of methane emission from upstream, middle stream and downstream of oil & gas sectors are identified and categorised as per IPCC-2006 guidelines. Data were collected from various oil & gas sector like (i) exploration & production of oil & gas (ii) supply through pipel...

  6. Methane production by sheep and cattle in Australia

    OpenAIRE

    MINSON, D. J.

    2011-01-01

    Using methane production rates from Australian feeds and local estimates of the quantity of feed eaten by different classes of animal, it was estimated that sheep and cattle in Australia produce 2.66 Tg methane in 1990. This value is 43% higher than previous estimates and indicates a need to reassess the methane production of ruminants in other countries.DOI: 10.1034/j.1600-0889.1993.00008.x

  7. Overview of California's Efforts to Understand and Reduce Methane Sources

    Science.gov (United States)

    Croes, B. E.; Chen, Y.; Duren, R. M.; Falk, M.; Franco, G.; Herner, J.; Ingram, W.; Kuwayama, T.; McCarthy, R.; Scheehle, E.; Vijayan, A.

    2016-12-01

    Methane is an important short-lived climate pollutant (SLCP) and also has significant health implications as a tropospheric ozone precursor. As part of a comprehensive effort to reduce greenhouse gas (GHG) emissions overall by 40% from 1990 levels by 2030, California has proposed an SLCP Strategy that includes a 40% reduction of methane emissions from 2013 levels by 2030, with goals to reduce oil and gas related emissions and capture methane emissions from dairy operations and organic waste. A recent analysis of satellite data found a large methane "hot spot" over the Central Valley in California, likely the second largest over the entire U.S. In light of this finding, the California legislature passed Assembly Bill 1496 in 2015, which requires the California Air Resources Board (CARB) to undertake measurements to understand the sources of methane hot spots, evaluate life-cycle emissions from natural gas imported into California, and update relevant policies and programs. There is growing evidence in the recent scientific literature suggesting that a small fraction of methane sources within a category emit disproportionately higher emissions than their counterparts, usually referred to as "super emitters". As such, controlling these sources may provide a lower cost opportunity for methane reductions needed to meet near- and long-term climate goals. In order to achieve a comprehensive understanding of sources contributing to "hot spots", CARB, the California Energy Commission, and NASA's Jet Propulsion Laboratory are implementing a large-scale statewide methane survey using a tiered monitoring and measurement program, which will include airborne and ground-level measurements of the various regions and source sectors in the State. This presentation will discuss research and program implementation efforts to evaluate and mitigate methane super emitters and hot spots. These efforts are expected to improve our understanding of methane emission source distributions

  8. Effect of sediment composition on methane concentration and production in the transition zone of a mangrove (Sepetiba Bay, Rio de Janeiro, Brazil Efeito da composição do sedimento sobre a concentração e a produção do metano na zona de transição de um mangue tropical, na Baía de Sepetiba-RJ, Brasil

    Directory of Open Access Journals (Sweden)

    CC. Marinho

    2012-08-01

    Full Text Available The aim of this research was to evaluate the effect of sediment composition on methane (CH4 dynamics in sediments of different areas in the transition zone between a mangrove and the sea. This research was conducted in a mangrove at Coroa Grande, on the southern coast of Rio de Janeiro. Samples were collected at three stations: (1 region colonised by Rhizophora mangle L. on the edge of the mangrove, (2 region colonised by seagrasses and (3 infra-littoral region without vegetation. Samples were collected from the surface layer of the sediment to determine the concentrations of nutrients (C, N and P and CH4 concentration and production. We observed that concentrations of CH4 and carbon (C were significantly higher (p O objetivo desta pesquisa foi avaliar a dinâmica do metano (CH4 no sedimento em diferentes áreas na região de transição entre a borda do manguezal e o mar, em função da composição do sedimento. A pesquisa foi realizada no Manguezal de Coroa Grande, no litoral sul do Estado do Rio de janeiro. Foram coletadas amostras em três estações: (1 região colonizada por Rhizophora mangle L. na borda do mangue, (2 região colonizada por macrófitas, e (3 região sem vegetação, permanentemente inundada pelo mar. Foram coletadas amostras da fração superficial do sedimento para determinação da concentração de nutrientes (C, N e P, e da concentração e da produção de CH4. Foi observado que as concentrações de CH4 e carbono (C foram significativamente maiores (p < 0,05 na estação 1, em relação à estação 3. Com relação às razões molares (C:N, C:P e N:P, estas indicam que a origem da composição do substrato é principalmente autóctone. Quanto à metanogênese, foram observados, inicialmente, baixos valores de CH4 produzido, indicando provável competição entre metanogênicos e sulfatorredutores. Seguiu-se, então, um significativo aumento (p < 0,05 da metanogênese no 26º dia, no sedimento da estação 1

  9. Bay BC's: A Multidisciplinary Approach To Teaching about the Chesapeake Bay.

    Science.gov (United States)

    Slattery, Britt Eckhardt

    The Chesapeake Bay is the largest estuary in North America, providing food and habitat for an abundance of fish and wildlife. This booklet provides lesson plans for lower elementary students introducing the Chesapeake, its inhabitants, and pollution problems, and suggesting ways that individuals can contribute to the Bay's restoration. Background…

  10. BOOK REVIEW OF "CHESAPEAKE BAY BLUES: SCIENCE, POLITICS, AND THE STRUGGLE TO SAVE THE BAY"

    Science.gov (United States)

    This is a book review of "Chesapeake Bay Blues: Science, Politics, and the Struggle to Save the Bay". This book is very well written and provides an easily understandable description of the political challenges faced by those proposing new or more stringent environmental regulat...

  11. 76 FR 28309 - Drawbridge Operation Regulation; Sturgeon Bay Ship Canal, Sturgeon Bay, WI

    Science.gov (United States)

    2011-05-17

    ... vehicular traffic congestion would not develop on downtown Sturgeon Bay streets due to unscheduled bridge... schedules during the peak tourist and navigation seasons to provide for the efficient movement of vehicular... between Lake Michigan and Green Bay. The area experiences a significant increase in vehicular and vessel...

  12. 77 FR 21890 - Drawbridge Operation Regulation; Sturgeon Bay Ship Canal, Sturgeon Bay, WI

    Science.gov (United States)

    2012-04-12

    ... Street and Maple-Oregon Bridges so vehicular traffic congestion would not develop on downtown Sturgeon... the efficient movement of vehicular traffic in Sturgeon Bay. The Sturgeon Bay Ship Canal is... experiences a significant increase in vehicular and vessel traffic during the peak tourist and navigation...

  13. Map showing thickness of young bay mud, southern San Francisco Bay, California

    Science.gov (United States)

    McDonald, Sandra D.; Nichols, Donald R.; Wright, Nancy A.; Atwater, Brian

    1978-01-01

    Soft water-saturated estuarine deposits less than 10,000 years old underlie the southern part of San Francisco bay and the present and former marshlands that border the bay. Known locally as bay mud or as young bay mud, these deposits, and the estuarine environment that produces them, are of major importance in making decision on land use and development in the San Francisco Bay area. Knowledge of the distribution, thickness, and physical properties of young bay mud is critical to the feasibility, design, and maintenance of structures built on it. Fore this reason, numerous attempts have been made in the past to map or describe these characteristics (Mitchell, 1963; Goldman, 1969; McDonald and Nichols, 1974). The accompanying map of bay-mud thickness significantly revises part of an earlier compilation by Kahle and Goldman (1969) and includes new data from approximately 2400 boreholes, most of which have been drilled during the past 15 years. It also incorporates information on historic margins of San Francisco Bay and its tidal marshes (Nichols and Wright, 1971). Although this map was compelled mostly from data gathered during foundation investigations and construction projects, it is mostly from data gathered during foundation investigations and construction projects, it is not a substitute for such studies. Rather, the map provides regional information for land-use planning, seismic zonation, and design of foundation investigations.

  14. Habitat Restoration on Mobile Bay

    Science.gov (United States)

    Murphy, B.

    2017-12-01

    Alabama has some of the most biodiversity found anywhere in our nation, however we are rapidly losing many of these species to habitat loss. Our marine science class realized our shoreline on our campus on Mobile Bay was disappearing and wanted to help. We collaborated with local scientists from Dauphin Island Sea Lab under the direction of Dr. Just Cebrian and our instructor, Dr. Megan McCall, to create a project to help restore the habitat. We had to first collect beach profile surveys and learn how to measure elevations. Next we installed plants that we measured and collected growth data. Our project went through a series of prototypes and corrective measures based on the type of wave energy we discovered on our shores. Finally we landed on a type of wave attenuator of crab traps filled with rock and staked into the sand. This coming year we will begin collecting data on any changes to the beach profile as well as fish counts to evaluate the effectiveness of our installation.

  15. Influenza in Bristol Bay, 1919

    Directory of Open Access Journals (Sweden)

    Maria Gilson deValpine

    2015-03-01

    Full Text Available The 1918 influenza pandemic has been blamed for as many as 50 million deaths worldwide. Like all major disasters, the full story of the pandemic includes smaller, less noted episodes that have not attracted historical attention. The story of the 1919 wave of the influenza pandemic in Bristol Bay Alaska is one such lost episode. It is an important story because the most accessible accounts—the Congressional Record and the Coast Guard Report—are inconsistent with reports made by employees, health care workers, and volunteers at the site of the disaster. Salmon fishing industry supervisors and medical officers recorded their efforts to save the region’s Native Alaskans in private company reports. The federal Bureau of Education physician retained wireless transmission, reports, and letters of events. The Coast Guard summarized its work in its Annual Report of 1920. The independent Bureau of Fisheries report to the Department of Commerce reveals the Coast Guard report at striking odds with others and reconciles only one account. This article explores the historical oversight, and attempts to tell the story of the 1919 wave of the pandemic which devastated the Native Alaskan population in this very remote place.

  16. Methane and carbon dioxide ratio in excreted air for quantification of the methane production from ruminants

    DEFF Research Database (Denmark)

    Madsen, Jørgen; Bjerg, Bjarne Schmidt; Hvelplund, Torben

    2010-01-01

    This technical note presents a simple, fast, reliable and cheap method to estimate the methane (CH4) production from animals by using the CH4 and carbon dioxide (CO2) concentrations in air near the animals combined with an estimation of the total CO2 production from information on intake of metab......This technical note presents a simple, fast, reliable and cheap method to estimate the methane (CH4) production from animals by using the CH4 and carbon dioxide (CO2) concentrations in air near the animals combined with an estimation of the total CO2 production from information on intake...

  17. Method for determination of methane potentials of solid organic waste

    International Nuclear Information System (INIS)

    Hansen, Trine L.; Schmidt, Jens Ejbye; Angelidaki, Irini; Marca, Emilia; Jansen, Jes la Cour; Mosboek, Hans; Christensen, Thomas H.

    2004-01-01

    A laboratory procedure is described for measuring methane potentials of organic solid waste. Triplicate reactors with 10 grams of volatile solids were incubated at 55 deg. C with 400 ml of inoculum from a thermophilic biogas plant and the methane production was followed over a 50-day period by regular measurements of methane on a gas chromatograph. The procedure involves blanks as well as cellulose controls. Methane potentials have been measured for source-separated organic household waste and for individual waste materials. The procedure has been evaluated regarding practicality, workload, detection limit, repeatability and reproducibility as well as quality control procedures. For the source-separated organic household waste a methane potential of 495 ml CH 4 /g VS was found. For fat and oil a lag-phase of several days was seen. The protein sample was clearly inhibited and the maximal methane potential was therefore not achieved. For paper bags, starch and glucose 63, 84 and 94% of the theoretical methane potential was achieved respectively. A detection limit of 72.5 ml CH 4 /g VS was calculated from the results. This is acceptable, since the methane potential of the tested waste materials was in the range of 200-500 ml CH 4 /g VS. The determination of methane potentials is a biological method subject to relatively large variation due to the use of non-standardized inoculum and waste heterogeneity. Therefore, procedures for addressing repeatability and reproducibility are suggested

  18. Trace methane oxidation studied in several Euryarchaeota under diverse conditions

    Directory of Open Access Journals (Sweden)

    James J. Moran

    2005-01-01

    Full Text Available We used 13C-labeled methane to document the extent of trace methane oxidation by Archaeoglobus fulgidus, Archaeoglobus lithotrophicus, Archaeoglobus profundus, Methanobacterium thermoautotrophicum, Methanosarcina barkeri and Methanosarcina acetivorans. The results indicate trace methane oxidation during growth varied among different species and among methanogen cultures grown on different substrates. The extent of trace methane oxidation by Mb. thermoautotrophicum (0.05 ± 0.04%, ± 2 standard deviations of the methane produced during growth was less than that by M. barkeri (0.15 ± 0.04%, grown under similar conditions with H2 and CO2. Methanosarcina acetivorans oxidized more methane during growth on trimethylamine (0.36 ± 0.05% than during growth on methanol (0.07 ± 0.03%. This may indicate that, in M. acetivorans, either a methyltransferase related to growth on trimethylamine plays a role in methane oxidation, or that methanol is an intermediate of methane oxidation. Addition of possible electron acceptors (O2, NO3–, SO22–, SO32– or H2 to the headspace did not substantially enhance or diminish methane oxidation in M. acetivorans cultures. Separate growth experiments with FAD and NAD+ showed that inclusion of these electron carriers also did not enhance methane oxidation. Our results suggest trace methane oxidized during methanogenesis cannot be coupled to the reduction of these electron acceptors in pure cultures, and that the mechanism by which methane is oxidized in methanogens is independent of H2 concentration. In contrast to the methanogens, species of the sulfate-reducing genus Archaeoglobus did not significantly oxidize methane during growth (oxidizing 0.003 ± 0.01% of the methane provided to A. fulgidus, 0.002 ± 0.009% to A. lithotrophicus and 0.003 ± 0.02% to A. profundus. Lack of observable methane oxidation in the three Archaeoglobus species examined may indicate that methyl-coenzyme M reductase, which is not present in

  19. Production and emission of methane and carbon dioxide by ruminants

    International Nuclear Information System (INIS)

    Chouinard, Y.

    2003-01-01

    Animal digestion is responsible for the production of both carbon dioxide and methane, while breathing produces only carbon dioxide. The author described the digestion mechanism of ruminants, explaining that they produce higher levels of methane and carbon dioxide than other animals. Fermentation stoichiometry of ruminants was also discussed along with the influence that diet has on methane production. It was noted that methane production can be decreased by increasing animal productivity, or by using ionophore antibiotics and long chain fatty acids. Test results from each of these methods have revealed side effects and none appears to be applicable for the time being. 10 refs., 1 tab., 1 fig

  20. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Don Augenstein

    1999-01-11

    ''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

  1. Methane emissions and climate compatibility of fossil fuels

    International Nuclear Information System (INIS)

    Meier, B.

    1992-01-01

    Methane contributes directly and indirectly to the additional greenhouse effect caused by human activities. The vast majority of the anthropogenic methane release occurs worldwide in non-fossil sources such as rice cultivation, livestock operations, sanitary landfills and combustion of bio-mass. Methane emissions also occur during production, distribution and utilisation of fossil fuels. Also when considering the methane release and CO 2 -emissions of processes upstream of combustion, the ranking of environmental compatibility of natural gas, fuel oil and cool remains unchanged. Of all fossil fuels, natural gas contributes the least to the greenhouse effect. (orig.) [de

  2. Microchannel Methanation Reactors Using Nanofabricated Catalysts, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  3. Methanization in Burgundy-Franche-Comte - Figures and benchmarks. Agricultural methanization in Franche-Comte - Reflection guide for projects. Methanization development in Burgundy - Assessment 2014. Biogas sector in Burgundy. Methanization development in Burgundy - How to develop a project in Burgundy

    International Nuclear Information System (INIS)

    Aucordonnier, Bertrand; SIBUE, Lionel; Granger, Sylvie; Pervenchon, Frank; Forgue, Isabelle; Lirzin, Frank; Aucordonnier, Bertand; Abrahamse, Philippe; Dondaine, Regis; Rousseau, Christophe; Fevre, Jean-Michel; Carbonnier, Arnaud; Gontier, Thomas; Lemaire, Sylvie; Gallois, Vincent; Lachaize, M.

    2015-03-01

    A first document proposes graphs, figures and maps which illustrate various aspects of the situation and development of methanization in France and in the Burgundy-Franche-Comte region (number and location of installations, production evolution, biomass origins, biogas valorisation). A second document presents methanization (basic principles, process types, valorisation), describes agricultural methanization (substrate origin, use of final energy, use of digestates) and proposes elements of thought for methanization development regarding waste origin, project definition, various concerns (energy, environment, agriculture), digestate use and quantities, methane use, and installation sizing. A publication then proposes a synthetic overview of methanization development in Burgundy: number of supported projects, installations (evolution of their number, used materials, production), and support activities. The next publication proposes an assessment and an overview of the biogas sector in Burgundy: presentation and recommendations, assessment in terms of jobs, activities and expertise, professional education and training. The last document recalls some elements related to the methanization technique, outlines some important issues (materials, valorisation type for biogas and for digestate) to be addressed for an agricultural methanization project, and evokes benefits of methanization and some economic aspects. It also briefly describes how to start a project in the region

  4. Methanization of industrial liquid effluents; Methanisation des effluents industriels liquides

    Energy Technology Data Exchange (ETDEWEB)

    Frederic, S.; Lugardon, A. [Societe Naskeo Environnement, 92 - Levallois-Perret (France)

    2007-09-15

    In a first part, this work deals with the theoretical aspects of the methanization of the industrial effluents; the associated reactional processes are detailed. The second part presents the technological criteria for choosing the methanization process in terms of the characteristics of the effluent to be treated. Some of the methanization processes are presented with their respective advantages and disadvantages. At last, is described the implementation of an industrial methanization unit. The size and the main choices are detailed: the anaerobic reactor, the control, the valorization aspects of the biogas produced. Some examples of industrial developments illustrate the different used options. (O.M.)

  5. Exhaled methane concentration profiles during exercise on an ergometer

    Science.gov (United States)

    Szabó, A; Ruzsanyi, V; Unterkofler, K; Mohácsi, Á; Tuboly, E; Boros, M; Szabó, G; Hinterhuber, H; Amann, A

    2016-01-01

    Exhaled methane concentration measurements are extensively used in medical investigation of certain gastrointestinal conditions. However, the dynamics of endogenous methane release is largely unknown. Breath methane profiles during ergometer tests were measured by means of a photoacoustic spectroscopy based sensor. Five methane-producing volunteers (with exhaled methane level being at least 1 ppm higher than room air) were measured. The experimental protocol consisted of 5 min rest—15 min pedalling (at a workload of 75 W)—5 min rest. In addition, hemodynamic and respiratory parameters were determined and compared to the estimated alveolar methane concentration. The alveolar breath methane level decreased considerably, by a factor of 3–4 within 1.5 min, while the estimated ventilation-perfusion ratio increased by a factor of 2–3. Mean pre-exercise and exercise methane concentrations were 11.4 ppm (SD:7.3) and 2.8 ppm (SD:1.9), respectively. The changes can be described by the high sensitivity of exhaled methane to ventilationperfusion ratio and are in line with the Farhi equation. PMID:25749807

  6. Methane yield enhancement via electroporation of organic waste.

    Science.gov (United States)

    Safavi, Seyedeh Masoumeh; Unnthorsson, Runar

    2017-08-01

    An experimental study with pulsed electric field (PEF) pre-treatment was conducted to investigate its effect on methane production. PEF pre-treatment converts organic solids into soluble and colloidal forms, increasing bioavailability for anaerobic microorganisms participating in methane generation process. The substrates tested were landfill leachate and fruit/vegetable. Three treatment intensities of 15, 30, and 50kWh/m 3 were applied to investigate the influence of pre-treatment on methane production via biochemical methane potential test. Threshold treatment intensity was found to be around 30kWh/m 3 for landfill leachate beyond which the methane production enhanced linearly with increase in intensity. Methane production of the landfill leachate significantly increased up to 44% with the highest intensity. The result of pulsed electric field pre-treatment on fruit/vegetable showed that 15kWh/m 3 was the intensity by which the highest amount of methane (up to 7%) was achieved. Beyond this intensity, the methane production decreased. Chemical oxygen demand removals were increased up to 100% for landfill leachate and 17% for fruit/vegetable, compared to the untreated slurries. Results indicate that the treatment intensity has a significant effect on the methane production and biosolid removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Crenothrix are major methane consumers in stratified lakes.

    Science.gov (United States)

    Oswald, Kirsten; Graf, Jon S; Littmann, Sten; Tienken, Daniela; Brand, Andreas; Wehrli, Bernhard; Albertsen, Mads; Daims, Holger; Wagner, Michael; Kuypers, Marcel Mm; Schubert, Carsten J; Milucka, Jana

    2017-09-01

    Methane-oxidizing bacteria represent a major biological sink for methane and are thus Earth's natural protection against this potent greenhouse gas. Here we show that in two stratified freshwater lakes a substantial part of upward-diffusing methane was oxidized by filamentous gamma-proteobacteria related to Crenothrix polyspora. These filamentous bacteria have been known as contaminants of drinking water supplies since 1870, but their role in the environmental methane removal has remained unclear. While oxidizing methane, these organisms were assigned an 'unusual' methane monooxygenase (MMO), which was only distantly related to 'classical' MMO of gamma-proteobacterial methanotrophs. We now correct this assignment and show that Crenothrix encode a typical gamma-proteobacterial PmoA. Stable isotope labeling in combination swith single-cell imaging mass spectrometry revealed methane-dependent growth of the lacustrine Crenothrix with oxygen as well as under oxygen-deficient conditions. Crenothrix genomes encoded pathways for the respiration of oxygen as well as for the reduction of nitrate to N 2 O. The observed abundance and planktonic growth of Crenothrix suggest that these methanotrophs can act as a relevant biological sink for methane in stratified lakes and should be considered in the context of environmental removal of methane.

  8. SHIMS -- A Spatial Heterodyne Interferometer for Methane Sounding, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project develops the Spatial Heterodyne Interferometer for Methane Sounding (SHIMS), a lightweight, compact, robust spectrometer system for remote sensing of...

  9. Microchannel Methanation Reactors Using Nanofabricated Catalysts, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  10. UPGRADING METHANE USING ULTRA-FAST THERMAL SWING ADSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Anna Lee Tonkovich

    2004-01-01

    The purpose of this project is to design and demonstrate an approach to upgrade low-BTU methane streams from coal mines to pipeline-quality natural gas. The objective of Phase I of the project was to assess the feasibility of upgrading low-Btu methane streams using ultra-fast thermal swing adsorption (TSA) using Velocys' modular microchannel process technology. The project is on schedule and under budget. For Task 1.1, the open literature, patent information, and vendor contacts were surveyed to identify adsorbent candidates for experimental validation and subsequent demonstration in an MPT-based ultra-fast TSA separation for methane upgrading. The leading candidates for preferential adsorption of methane over nitrogen are highly microporous carbons. A Molecular Gate{trademark} zeolite from Engelhard Corporation has emerged as a candidate. For Task 1.2, experimental evaluation of adsorbents was initiated, and data were collected on carbon (MGN-101) from PICA, Inc. This carbon demonstrated a preferential capacity for methane over nitrogen, as well as a reasonable thermal swing differential capacity for a 90% methane and 10% nitrogen mixture. A similar methane swing capacity at 2 psig was measured. The mixture composition is relevant because gob gas contains nearly 85% methane and must be purified to 97% methane for pipeline quality.

  11. Hydrogen Recovery by ECR Plasma Pyrolysis of Methane, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a microgravity and hypogravity compatible Electron Cyclotron Resonance (ECR) Plasma Methane Pyrolysis Reactor is proposed to recover hydrogen which is...

  12. Dynamics of archaea at fine spatial scales in Shark Bay mat microbiomes

    Science.gov (United States)

    Wong, Hon Lun; Visscher, Pieter T.; White, Richard Allen, III; Smith, Daniela-Lee; Patterson, Molly M.; Burns, Brendan P.

    2017-04-01

    The role of archaea in microbial mats is poorly understood. Delineating the spatial distribution of archaea with mat depth will enable resolution of putative niches in these systems. In the present study, high throughput amplicon sequencing was undertaken in conjunction with analysis of key biogeochemical properties of two mats (smooth and pustular) from Shark Bay, Australia. One-way analysis of similarity tests indicated the archaeal community structures of smooth and pustular mats were significantly different (global R = 1, p = 0.1%). Smooth mats possessed higher archaeal diversity, dominated by Parvarchaeota. The methanogenic community in smooth mats was dominated by hydrogenotrophic Methanomicrobiales, as well as methylotrophic Methanosarcinales, Methanococcales, Methanobacteriales and Methanomassiliicoccaceae. Pustular mats were enriched with Halobacteria and Parvarchaeota. Key metabolisms (bacterial and archaeal) were measured, and the rates of oxygen production/consumption and sulfate reduction were up to four times higher in smooth than in pustular mats. Methane production peaked in the oxic layers and was up to seven-fold higher in smooth than pustular mats. The finding of an abundance of anaerobic methanogens enriched at the surface where oxygen levels were highest, coupled with peak methane production in the oxic zone, suggests putative surface anoxic niches in these microbial mats.

  13. Methane anomalies in seawaters of the Ragay Gulf, Philippines: methane cycling and contributions to atmospheric greenhouse gases

    International Nuclear Information System (INIS)

    Heggie, D.T.; Evans, D.; Bishop, J.H.

    1999-01-01

    The vertical distribution of methane has been measured in the water column of a semi-enclosed basin, the Ragay Gulf, in the Philippines archipelago. The methane distribution is characterised by unusual mid-water and bottom-water plumes, between 80 and 100 m thick. The plumes are confined to water depths between about 100 and 220 m. where the temperature-depth (a proxy for seawater density) gradient is steepest. Plumes of high methane are 'trapped' within the main thermocline; these are local features, persisting over kilometre-scale distances. Geochemical and geological evidence suggests that the elevated methane concentrations are thermogenic in origin (although an oxidised biogenic origin cannot be ruled out for some of the methane anomalies), and have migrated from the sea floor into the overlying water. The mid and bottom-water methane maxima support fluxes of methane from depth into surface waters and, subsequently, from the oceans to the atmosphere. The average supersaturation of methane in the top 5 m of the sea, at nine locations, was 206±16.5%; range 178-237%. The average estimated sea-air flux was 101 nmole.cm -2 .y -1 and probably represents a minimum flux, because of low wind speeds of <10 knots. These fluxes, we suggest, are supported by seepage from the sea floor and represent naturally occurring fluxes of mostly fossil methane (in contrast to anthropogenic fossil methane), from the sea to the atmosphere. The estimated minimum fluxes of naturally occurring fossil methane are comparable to those biogenic fluxes measured elsewhere in the surface oceans, but are less than those naturally occurring methane inputs from sediments of the Barents Sea. Ragay Gulf fluxes are also less than anthropogenic fluxes measured in areas of petroleum exploration and development, such as the Texas and Louisiana, USA shelf areas

  14. Methane Flux and Authigenic Carbonate in Shallow Sediments Overlying Methane Hydrate Bearing Strata in Alaminos Canyon, Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Joseph P. Smith

    2014-09-01

    Full Text Available In June 2007 sediment cores were collected in Alaminos Canyon, Gulf of Mexico across a series of seismic data profiles indicating rapid transitions between the presence of methane hydrates and vertical gas flux. Vertical profiles of dissolved sulfate, chloride, calcium, magnesium, and dissolved inorganic carbon (DIC concentrations in porewaters, headspace methane, and solid phase carbonate concentrations were measured at each core location to investigate the cycling of methane-derived carbon in shallow sediments overlying the hydrate bearing strata. When integrated with stable carbon isotope ratios of DIC, geochemical results suggest a significant fraction of the methane flux at this site is cycled into the inorganic carbon pool. The incorporation of methane-derived carbon into dissolved and solid inorganic carbon phases represents a significant sink in local carbon cycling and plays a role in regulating the flux of methane to the overlying water column at Alaminos Canyon. Targeted, high-resolution geochemical characterization of the biogeochemical cycling of methane-derived carbon in shallow sediments overlying hydrate bearing strata like those in Alaminos Canyon is critical to quantifying methane flux and estimating methane hydrate distributions in gas hydrate bearing marine sediments.

  15. Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

    OpenAIRE

    Borowski Marek; Kuczera Zbigniew

    2018-01-01

    Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on ...

  16. Study on headland-bay sandy coast stability in South China coasts

    Science.gov (United States)

    Yu, Ji-Tao; Chen, Zi-Shen

    2011-03-01

    Headland-bay beach equilibrium planform has been a crucial problem abroad to long-term sandy beach evolution and stabilization, extensively applied to forecast long-term coastal erosion evolvement and the influences of coastal engineering as well as long-term coastal management and protection. However, little concern focuses on this in China. The parabolic relationship is the most widely used empirical relationship for determining the static equilibrium shape of headland-bay beaches. This paper utilizes the relation to predict and classify 31 headland-bay beaches and concludes that these bays cannot achieve the ultimate static equilibrium planform in South China. The empirical bay equation can morphologically estimate beach stabilization state, but it is just a referential predictable means and is difficult to evaluate headland-bay shoreline movements in years and decades. By using Digital Shoreline Analysis System suggested by USGS, the rates of shoreline recession and accretion of these different headland-bay beaches are quantitatively calculated from 1990 to 2000. The conclusions of this paper include that (a) most of these 31 bays maintain relatively stable and the rates of erosion and accretion are relatively large with the impact of man-made constructions on estuarine within these bays from 1990 to 2000; (b) two bays, Haimen Bay and Hailingshan Bay, originally in the quasi-static equilibrium planform determined by the parabolic bay shape equation, have been unstable by the influence of coastal engineering; and (c) these 31 bays have different recession and accretion characters occurring in some bays and some segments. On the one hand, some bays totally exhibit accretion, but some bays show erosion on the whole. Shanwei Bay, Houmen Bay, Pinghai Bay and Yazhou Bay have the similar planforms, characterized by less accretion on the sheltering segment and bigger accretion on the transitional and tangential segments. On the other hand, different segments of some

  17. Concentration of PSP (Paralytic Shellfish Poisoning) Toxin On Shellfish From Inner Ambon Bay and Kao Bay North Halmahera

    Science.gov (United States)

    Pello, F. S.; Haumahu, S.; Huliselan, N. V.; Tuapattinaja, M. A.

    2017-10-01

    The Inner Ambon Bay and Kao Bay have potential on fisheries resources which one of them is molluscs. Molluscs especially for class bivalve have economical values and are consumed by coastal community. The research had been done to analyze saxitoxin (STX) concentration on bivalves from Kao Bay and Inner Ambon Bay. The Saxitoxin Elisa Test Kit Protocol was used to determine saxitoxin concentration. The measurement showed that the highest concentration of saxitoxin (392.42 µg STXeq/100g shellfish meat) was Gafrarium tumidum from Ambon Bay, whereas concentration of saxitoxin (321.83 µg STXeq/100g shellfish meat) was Mactra mera from Kao Bay

  18. Mycobacteria isolated from Chesapeake Bay fish.

    Science.gov (United States)

    Stine, C B; Kane, A S; Baya, A M

    2010-01-01

    Mycobacteriosis in fish can result in ulcers, emaciation, and in some cases death. Mycobacteria have been previously isolated from a variety of Chesapeake Bay fish species, and the current study was designed to identify potential host specificity and location fidelity of mycobacterial isolates. Mycobacteria were isolated from wild fish of the Chesapeake Bay collected from the Upper Bay, the Choptank River, Herring Bay, the Chicamacomico River, the Pocomoke River and the Potomac River in 2003-2006. Mycobacterial isolates were recovered from striped bass, Morone saxatilis, Atlantic menhaden, Brevoortia tyrannus, white perch, Morone americana, summer flounder, Paralichthys dentatus, spot, Leiostomus xanthurus, largemouth bass, Micropterus salmoides, channel catfish, Ictalurus punctatus, common carp, Cyprinus carpio carpio, spotted seatrout, Cynoscion nebulosus, killifish, Fundulus sp., blueback herring, Alosa aestivalis, American gizzard shad, Dorosoma cepedianum and American silver perch, Bairdiella chrysoura. Twenty-nine well-defined mycobacterial groups resulted from gas chromatography dendrogram clustering of isolates. The majority of groups included more than one host species and more than one site of collection. However, four groups contained only striped bass isolates, three of which were similar to M. shottsii. Therefore, multiple Chesapeake Bay fish species are colonized with multiple mycobacterial isolates, of which few appear to be host or location specific.

  19. Changing Salinity Patterns in Biscayne Bay, Florida

    Science.gov (United States)

    ,

    2004-01-01

    Biscayne Bay, Fla., is a 428-square-mile (1,109-square-kilometer) subtropical estuarine ecosystem that includes Biscayne National Park, the largest marine park in the U.S. national park system (fig. 1). The bay began forming between 5,000 and 3,000 years ago as sea level rose and southern Florida was flooded. Throughout most of its history, the pristine waters of the bay supported abundant and diverse fauna and flora, and the bay was a nursery for the adjacent coral-reef and marine ecosystems. In the 20th century, urbanization of the Miami-Dade County area profoundly affected the environment of the bay. Construction of powerplants, water-treatment plants, and solid-waste sites and large-scale development along the shoreline stressed the ecosystem. Biscayne National Monument was established in 1968 to ?preserve and protect for the education, inspiration, recreation and enjoyment of present and future generations a rare combination of terrestrial, marine, and amphibious life in a tropical setting of great natural beauty? (Public Law 90?606). The monument was enlarged in 1980 and designated a national park.

  20. Exploiting coalbed methane and protecting the global environment

    Energy Technology Data Exchange (ETDEWEB)

    Yuheng, Gao

    1996-12-31

    The global climate change caused by greenhouse gases (GHGs) emission has received wide attention from all countries in the world. Global environmental protection as a common problem has confronted the human being. As a main component of coalbed methane, methane is an important factor influencing the production safety of coal mine and threatens the lives of miners. The recent research on environment science shows that methane is a very harmful GHG. Although methane gas has very little proportion in the GHGs emission and its stayed period is also very short, it has very obvious impact on the climate change. From the estimation, methane emission in the coal-mining process is only 10% of the total emission from human`s activities. As a clean energy, Methane has mature recovery technique before, during and after the process of mining. Thus, coalbed methane is the sole GHG generated in the human`s activities and being possible to be reclaimed and utilized. Compared with the global greenhouse effect of other GHGs emission abatement, coalbed methane emission abatement can be done in very low cost with many other benefits: (1) to protect global environment; (2) to improve obviously the safety of coal mine; and (3) to obtain a new kind of clean energy. Coal is the main energy in China, and coalbed contains very rich methane. According to the exploration result in recent years, about 30000{approximately}35000 billion m{sup 2} methane is contained in the coalbed below 2000 m in depth. China has formed a good development base in the field of reclamation and utilization of coalbed methane. The author hopes that wider international technical exchange and cooperation in the field will be carried out.

  1. Trace methane oxidation and the methane dependency of sulfate reduction in anaerobic granular sludge

    NARCIS (Netherlands)

    Meulepas, R.J.W.; Jagersma, C.G.; Zhang, Y.; Petrillo, M.; Cai, H.; Buisman, C.J.N.; Stams, A.J.M.; Lens, P.N.L.

    2010-01-01

    This study investigates the oxidation of labeled methane (CH(4)) and the CH(4) dependence of sulfate reduction in three types of anaerobic granular sludge. In all samples, (13)C-labeled CH(4) was anaerobically oxidized to (13)C-labeled CO(2), while net endogenous CH(4) production was observed.

  2. METABOLISM OF CHLORINATED METHANES, ETHANES, AND ETHYLENES BY A MIXED BACTERIAL CUTLURE GROWING ON METHANE

    Science.gov (United States)

    Soil was taken from the top 10 cm of a soil column that removed halogenated aliphatic hydrocarbons in the presence of natural gas. This soil was used as an enrichment inoculum to determine that the removals seen in the soil column were in fact of a microbiological nature. Methane...

  3. Effect of bubble size and density on methane conversion to hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Leske, J.; Taylor, C.E.; Ladner, E.P.

    2007-03-01

    Research is underway at NETL to understand the physical properties of methane hydrates. One area of investigation is the storage of methane as methane hydrates. An economical and efficient means of storing methane in hydrates opens many commercial opportunities such as transport of stranded gas, off-peak storage of line gas, etc.We have observed during our investigations that the ability to convert methane to methane hydrate is enhanced by foaming of the methane–water solution using a surfactant. The density of the foam, along with the bubble size, is important in the conversion of methane to methane hydrate.

  4. Mobile mapping of methane emissions and isoscapes

    Science.gov (United States)

    Takriti, Mounir; Ward, Sue; Wynn, Peter; Elias, Dafydd; McNamara, Niall

    2017-04-01

    Methane (CH4) is a potent greenhouse gas emitted from a variety of natural and anthropogenic sources. It is crucial to accurately and efficiently detect CH4 emissions and identify their sources to improve our understanding of changing emission patterns as well as to identify ways to curtail their release into the atmosphere. However, using established methods this can be challenging as well as time and resource intensive due to the temporal and spatial heterogeneity of many sources. To address this problem, we have developed a vehicle mounted mobile system that combines high precision CH4 measurements with isotopic mapping and dual isotope source characterisation. We here present details of the development and testing of a unique system for the detection and isotopic analysis of CH4 plumes built around a Picarro isotopic (13C/12C) gas analyser and a high precision Los Gatos greenhouse gas analyser. Combined with micrometeorological measurements and a mechanism for collecting discrete samples for high precision dual isotope (13C/12C, 2H/1H) analysis the system enables mapping of concentrations as well as directional and isotope based source verification. We then present findings from our mobile methane surveys around the North West of England. This area includes a variety of natural and anthropogenic methane sources within a relatively small geographical area, including livestock farming, urban and industrial gas infrastructure, landfills and waste water treatment facilities, and wetlands. We show that the system was successfully able to locate leaks from natural gas infrastructure and emissions from agricultural activities and to distinguish isotope signatures from these sources.

  5. Shallow Aquifer Methane Gas Source Assessment

    Science.gov (United States)

    Coffin, R. B.; Murgulet, D.; Rose, P. S.; Hay, R.

    2014-12-01

    Shale gas can contribute significantly to the world's energy demand. Hydraulic fracturing (fracking) on horizontal drill lines developed over the last 15 years makes formerly inaccessible hydrocarbons economically available. From 2000 to 2035 shale gas is predicted to rise from 1% to 46% of the total natural gas for the US. A vast energy resource is available in the United States. While there is a strong financial advantage to the application of fracking there is emerging concern about environmental impacts to groundwater and air quality from improper shale fracking operations. Elevated methane (CH4) concentrations have been observed in drinking water throughout the United States where there is active horizontal drilling. Horizontal drilling and hydraulic-fracturing can increase CH4 transport to aquifers, soil and the vadose zone. Seepage can also result from casing failure in older wells. However, there is strong evidence that elevated CH4 concentrations can be associated with topographic and hydrogeologic features, rather than shale-gas extraction processes. Carbon isotope geochemistry can be applied to study CH4source(s) in shallow vadose zone and groundwater systems. A preliminary TAMU-CC isotope data set from samples taken at different locations in southern Texas shows a wide range of CH4 signatures suggesting multiple sources of methane and carbon dioxide. These data are interpreted to distinguish regions with methane contributions from deep-sourced horizontal drilling versus shallow system microbial production. Development of a thorough environmental assessment using light isotope analysis can provide understanding of shallow anthropogenic versus natural CH4sources and assist in identifying regions that require remedial actions.

  6. The operational methane retrieval algorithm for TROPOMI

    Directory of Open Access Journals (Sweden)

    H. Hu

    2016-11-01

    Full Text Available This work presents the operational methane retrieval algorithm for the Sentinel 5 Precursor (S5P satellite and its performance tested on realistic ensembles of simulated measurements. The target product is the column-averaged dry air volume mixing ratio of methane (XCH4, which will be retrieved simultaneously with scattering properties of the atmosphere. The algorithm attempts to fit spectra observed by the shortwave and near-infrared channels of the TROPOspheric Monitoring Instrument (TROPOMI spectrometer aboard S5P.The sensitivity of the retrieval performance to atmospheric scattering properties, atmospheric input data and instrument calibration errors is evaluated. In addition, we investigate the effect of inhomogeneous slit illumination on the instrument spectral response function. Finally, we discuss the cloud filters to be used operationally and as backup.We show that the required accuracy and precision of  < 1 % for the XCH4 product are met for clear-sky measurements over land surfaces and after appropriate filtering of difficult scenes. The algorithm is very stable, having a convergence rate of 99 %. The forward model error is less than 1 % for about 95 % of the valid retrievals. Model errors in the input profile of water do not influence the retrieval outcome noticeably. The methane product is expected to meet the requirements if errors in input profiles of pressure and temperature remain below 0.3 % and 2 K, respectively. We further find that, of all instrument calibration errors investigated here, our retrievals are the most sensitive to an error in the instrument spectral response function of the shortwave infrared channel.

  7. The Global Methane Budget 2000-2012

    Science.gov (United States)

    Saunois, Marielle; Bousquet, Philippe; Poulter, Benjamin; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; hide

    2016-01-01

    The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (approximately biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modeling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations).For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 TgCH4 yr(exp -1), range 540-568. About 60 of global emissions are anthropogenic (range 50-65%). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP

  8. Polymers preparation under methane plasma environment

    International Nuclear Information System (INIS)

    Yang Wubao; Cai Zeyong; Zhao Zhen; Qi Lu

    2008-01-01

    Polymers are prepared under methane plasma environment, and appear to be white, slightly yellow, soft thread-like powders and floc under optical microscope. The polymers contain --CH 3 , -CH 2 , C-O, -C=C-,-OH etc. functional groups, but no simplex carbons. It is found that the solubility of this polymer is less than 0.1mg·ml -1 in different organic solvent. The productivity of the polymers is higher under a plasma environment with higher ionization, higher polarization of neutral gas, lower environment temperature and less permittivity. (authors)

  9. The Global Methane Budget 2000-2012

    Science.gov (United States)

    Saunois, Marielle; Bousquet, Philippe; Poulter, Benjamin; Peregon, Anna; Ciais, Philippe; Canadell, Josep G.; Dlugokencky, Edward J.; Etiope, Giuseppe; Bastviken, David; Houweling, Sander; hide

    2016-01-01

    The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase, making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (approximately biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (exploiting atmospheric observations within an atmospheric inverse-modeling framework) and bottom-up models, inventories and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations).For the 2003-2012 decade, global methane emissions are estimated by top-down inversions at 558 TgCH4 yr(exp -1), range 540-568. About 60 of global emissions are anthropogenic (range 50-65%). Since 2010, the bottom-up global emission inventories have been closer to methane emissions in the most carbon-intensive Representative Concentrations Pathway (RCP8.5) and higher than all other RCP

  10. Methane from Syngas by Anaerobic Digestion

    OpenAIRE

    Shah, Sanjay; Bergland, Wenche Hennie; Bakke, Rune

    2017-01-01

    Anaerobic digestion (AD) is a prominent green technology used for methane production from organic waste. Previous studies have shown that the amount of CH4 produced during anaerobic digestion can be increased by adding inorganic electron donors such as H2 and CO, both which can be produced as syngas from wood. Syngas inflow is implemented in the ADM1 model and simulations are carried out with different syngas additions to a well-documented case of wastewater treatment plant sludge AD. Three d...

  11. Methanation process utilizing split cold gas recycle

    Science.gov (United States)

    Tajbl, Daniel G.; Lee, Bernard S.; Schora, Jr., Frank C.; Lam, Henry W.

    1976-07-06

    In the methanation of feed gas comprising carbon monoxide and hydrogen in multiple stages, the feed gas, cold recycle gas and hot product gas is mixed in such proportions that the mixture is at a temperature sufficiently high to avoid carbonyl formation and to initiate the reaction and, so that upon complete reaction of the carbon monoxide and hydrogen, an excessive adiabatic temperature will not be reached. Catalyst damage by high or low temperatures is thereby avoided with a process that utilizes extraordinarily low recycle ratios and a minimum of investment in operating costs.

  12. 1999 RoxAnn Data Points from Apalachicola Bay, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Apalachicola Bay National Estuarine Research Reserve and the NOAA Office for Coastal Management worked together to map benthic habitats within Apalachicola Bay,...

  13. SF Bay Water Quality Improvement Fund: Projects and Accomplishments

    Science.gov (United States)

    San Francisco Bay Water Quality Improvement Fund (SFBWQIF) projects listed here are part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  14. Sediment grab data from October 1999 in Apalachicola Bay, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Apalachicola Bay National Estuarine Research Reserve and the NOAA Office for Coastal Management worked together to map benthic habitats within Apalachicola Bay,...

  15. Endocrine disrupter - estradiol - in Chesapeake Bay tributaries

    Energy Technology Data Exchange (ETDEWEB)

    Dorabawila, Nelum [University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States); Gupta, Gian [University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States)]. E-mail: gcgupta@umes.edu

    2005-04-11

    Exogenous chemicals that interfere with natural hormonal functions are considered endocrine disrupting chemicals (EDCs). Estradiol (17{beta}-estradiol or E2) is the most potent of all xenoestrogens. Induction of vitellogenin (VTG) production in male fish occurs at E2 concentrations as low as 1 ng l{sup -1}. E2 reaches aquatic systems mainly through sewage and animal waste disposal. Surface water samples from ponds, rivers (Wicomico, Manokin and Pocomoke), sewage treatment plants (STPs), and coastal bays (Assawoman, Monie, Chincoteague, and Tangier Sound - Chesapeake Bay) on the Eastern Shore of Maryland were analyzed for E2 using enzyme linked immuno-sorbent assay (ELISA). E2 concentrations in river waters varied between 1.9 and 6.0 ng l{sup -1}. Highest E2 concentrations in river waters were observed immediately downstream of STPs. E2 concentrations in all the coastal bays tested were 2.3-3.2 ng l{sup -1}.

  16. Endocrine disrupter - estradiol - in Chesapeake Bay tributaries

    International Nuclear Information System (INIS)

    Dorabawila, Nelum; Gupta, Gian

    2005-01-01

    Exogenous chemicals that interfere with natural hormonal functions are considered endocrine disrupting chemicals (EDCs). Estradiol (17β-estradiol or E2) is the most potent of all xenoestrogens. Induction of vitellogenin (VTG) production in male fish occurs at E2 concentrations as low as 1 ng l -1 . E2 reaches aquatic systems mainly through sewage and animal waste disposal. Surface water samples from ponds, rivers (Wicomico, Manokin and Pocomoke), sewage treatment plants (STPs), and coastal bays (Assawoman, Monie, Chincoteague, and Tangier Sound - Chesapeake Bay) on the Eastern Shore of Maryland were analyzed for E2 using enzyme linked immuno-sorbent assay (ELISA). E2 concentrations in river waters varied between 1.9 and 6.0 ng l -1 . Highest E2 concentrations in river waters were observed immediately downstream of STPs. E2 concentrations in all the coastal bays tested were 2.3-3.2 ng l -1

  17. Meteorological research studies at Jervis Bay, Australia

    International Nuclear Information System (INIS)

    Clark, G.H.; Bendun, E.O.K.

    1974-07-01

    A climatological study of the winds and temperature from the Jervis Bay region which commenced in October 1970 has shown the presence of a coastal sea breeze and secondary bay breeze circulation system. In an attempt to define the influence of the Murray's Beach site on the local atmospheric dispersion, special smoke plume photography studies were conducted in the lower atmosphere. In June 1972 a meteorological acoustic sounding research programme was initiated at the Jervis Bay settlement. The aims of the research are to calibrate the sounder in terms of surface wind, turbulence and temperature measurements pertinent to a description of the lower atmospheric dispersion potential. Preliminary results on six months' data have shown encouraging correlations between the acoustic sounder patterns and particularly the wind direction turbulence traces. (author)

  18. Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

    Directory of Open Access Journals (Sweden)

    Borowski Marek

    2018-01-01

    Full Text Available Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in

  19. Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

    Science.gov (United States)

    Borowski, Marek; Kuczera, Zbigniew

    2018-03-01

    Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage) could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in the air; location

  20. Bio-methane via fast pyrolysis of biomass

    International Nuclear Information System (INIS)

    Görling, Martin; Larsson, Mårten; Alvfors, Per

    2013-01-01

    Highlights: ► Pyrolysis gases can efficiently be upgraded to bio-methane. ► The integration can increase energy efficiency and provide a renewable vehicle fuel. ► The biomass to bio-methane conversion efficiency is 83% (HHV). ► The efficiency is higher compared to bio-methane produced via gasification. ► Competitive alternative to other alternatives of bio-oil upgrading. - Abstract: Bio-methane, a renewable vehicle fuel, is today produced by anaerobic digestion and a 2nd generation production route via gasification is under development. This paper proposes a poly-generation plant that produces bio-methane, bio-char and heat via fast pyrolysis of biomass. The energy and material flows for the fuel synthesis are calculated by process simulation in Aspen Plus®. The production of bio-methane and bio-char amounts to 15.5 MW and 3.7 MW, when the total inputs are 23 MW raw biomass and 1.39 MW electricity respectively (HHV basis). The results indicate an overall efficiency of 84% including high-temperature heat and the biomass to bio-methane yield amounts to 83% after allocation of the biomass input to the final products (HHV basis). The overall energy efficiency is higher for the suggested plant than for the gasification production route and is therefore a competitive route for bio-methane production

  1. 30 CFR 75.1106-1 - Test for methane.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test for methane. 75.1106-1 Section 75.1106-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-1 Test for methane. Until December 31, 1970, a permissible flame...

  2. Observations on the methane oxidation capacity of landfill soils

    Science.gov (United States)

    Field data and two independent models indicate that landfill cover methane (CH4) oxidation should not be considered as a constant 10% or any other single value. Percent oxidation is a decreasing exponential function of the total methane flux rate into the cover and is also dependent on climate and c...

  3. Atmospheric Methane characterisation over the South African interior

    CSIR Research Space (South Africa)

    Feig, Gregor T

    2016-10-01

    Full Text Available The concentrations of atmospheric methane have an important impact on the global climate system and are important in the production of tropospheric ozone as it acts as an ozone precursor. The ambient concentrations of methane have increased more...

  4. Combining oxidative coupling and reforming of methane : vision or utopia?

    NARCIS (Netherlands)

    Graf, P.O.

    2009-01-01

    Methane, which is the principal component of natural gas reserves, is currently being used for home and industrial heating and for the generation of electrical power. Methane is an ideal fuel because of its availability in most populated centres, its ease of purification and the fact that is has the

  5. Methanotrophy controls groundwater methane export from a barrier island

    Science.gov (United States)

    Schutte, Charles A.; Wilson, Alicia M.; Evans, Tyler; Moore, Willard S.; Joye, Samantha B.

    2016-04-01

    Methane concentrations can be high in coastal groundwater, resulting in methane export driven by submarine groundwater discharge. However, the magnitude of this methane flux depends significantly on the rate of methanotrophy, the often overlooked process of microbial methane consumption that occurs within coastal aquifer sediments. Here we describe a zone of methanogenesis within the freshwater lens of a barrier island aquifer and investigate the methane source/sink behavior of the barrier island system as a whole. The median concentration of methane dissolved in fresh groundwater beneath the center of the island was 0.6 mM, supported by high rates of potential methanogenesis (22 mmol m-2 day-1). However, rates of microbial methane consumption were also elevated in surrounding sediments (18 mmol m-2 day-1). Groundwater flowing from the zone of methanogenesis to the point of discharge into the ocean had a long residence time within methanotrophic sediments (∼195 days) such that the majority of the methane produced within the barrier island aquifer was likely consumed there.

  6. 46 CFR 154.1854 - Methane (LNG) as fuel.

    Science.gov (United States)

    2010-10-01

    ... master shall ensure that the fuel oil fired pilot under § 154.705(c) is used when the vessel is on the... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Operations § 154.1854 Methane (LNG) as... ventilation or detection of gas, the master shall ensure that the methane (LNG) fuel supply is not used until...

  7. Estimation of methane generation based on anaerobic digestion ...

    African Journals Online (AJOL)

    ... comparable (within 14%) to the amount estimated by laboratory-scale anaerobic digestion experiment (1.43 Gg methane/month). It is a worthwhile undertaking to further investigate the potential of commercially producing methane from Kiteezi landfill as an alternative source of green and clean energy for urban masses.

  8. Root biomass as a major means of affecting methane emissions

    Science.gov (United States)

    Human activities are contributing to greenhouse gas emissions. Methane, the second most abundant greenhouse gas, is ~25 times more potent in global warming potential than carbon dioxide, and 7-17% of atmospheric methane comes from paddy rice fields. The purpose of the study was to investigate gene...

  9. Predicting methane emission of dairy cows using milk composition

    NARCIS (Netherlands)

    Gastelen, van Sanne

    2017-01-01

    Enteric methane (CH4) is produced as a result of microbial fermentation of feed components in the gastrointestinal tract of ruminant livestock. Methane has no nutritional value for the animal and is predominately released into the environment through eructation and breath.

  10. Investigating observational constraints on the contemporary methane budget

    NARCIS (Netherlands)

    Monteil, G.A.

    2014-01-01

    Methane (CH4) is an important greenhouse gas, naturally produced by bio-degradation of organic material (mainly in wetlands), by continuous and eruptive releases from mud volcanoes, and by combustion of organic material in forest and peat fires. Large quantities of methane are also emitted by human

  11. Reduce the methane hazards in collieries, vol. 1.

    CSIR Research Space (South Africa)

    Van Zyl, FJ

    1996-10-01

    Full Text Available In an effort to improve safety in the underground environment of a mechanical miner section, with relation to the methane hazard a data obtained with the multi-channel methane monitoring unit, combined with situ and laboratory coal analysis data...

  12. Mangosteen peel can reduce methane production and rumen ...

    African Journals Online (AJOL)

    Mangosteen peel (MP), an agricultural by-product of tropical countries, has been reported to contain condensed tannins and saponins, which can affect rumen microbes to reduce enteric methane emission. In the present study, the effects of mangosteen peel on in vitro ruminal fermentation, gas production, methane ...

  13. Methane formation in tritium gas exposed to stainless steel

    International Nuclear Information System (INIS)

    Morris, G.A.

    1977-01-01

    Tests were performed to determine the effect cleanliness of a surface exposed to tritium gas had on methane formation. These tests performed on 304 stainless steel vessels, cleaned in various ways, showed that the methane formation was reduced by the use of various cleaning procedures

  14. Biofiltration for Mitigation of Methane Emission from Animal Husbandry

    NARCIS (Netherlands)

    Melse, R.W.; Werf, van der A.W.

    2005-01-01

    Removal of methane from exhaust air of animal houses and manure storage has a large potential for the reduction of greenhouse gas emissions from animal husbandry. The aim of this study was to design a biofilter for methane removal at a full-scale livestock production facility. Air from the headspace

  15. Biological conversion of methane to liquid fuels: status and opportunities.

    Science.gov (United States)

    Ge, Xumeng; Yang, Liangcheng; Sheets, Johnathon P; Yu, Zhongtang; Li, Yebo

    2014-12-01

    Methane is the main component of natural gas and biogas. As an abundant energy source, methane is crucial not only to meet current energy needs but also to achieve a sustainable energy future. Conversion of methane to liquid fuels provides energy-dense products and therefore reduces costs for storage, transportation, and distribution. Compared to thermochemical processes, biological conversion has advantages such as high conversion efficiency and using environmentally friendly processes. This paper is a comprehensive review of studies on three promising groups of microorganisms (methanotrophs, ammonia-oxidizing bacteria, and acetogens) that hold potential in converting methane to liquid fuels; their habitats, biochemical conversion mechanisms, performance in liquid fuels production, and genetic modification to enhance the conversion are also discussed. To date, methane-to-methanol conversion efficiencies (moles of methanol produced per mole methane consumed) of up to 80% have been reported. A number of issues that impede scale-up of this technology, such as mass transfer limitations of methane, inhibitory effects of H2S in biogas, usage of expensive chemicals as electron donors, and lack of native strains capable of converting methane to liquid fuels other than methanol, are discussed. Future perspectives and strategies in addressing these challenges are also discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Non-oxidative methane dehydroaromatization reaction over highly ...

    Indian Academy of Sciences (India)

    Pradeep Kumar Budde

    2018-03-02

    Mar 2, 2018 ... an internal standard was used for the total gas outlet of the reactor. Here, 90% stands for vol%, keeping methane partial. Pressure = 0.9 bar while Nitrogen partial Pressure = 0.1bar, with a total pressure of 1 bar. Methane conversion, selectivity of hydrocarbons and coke formation was calculated based on.

  17. Situation of methanization installations in Haute-Normandie. Phase 2: Assessment of the regional sector. Phase 3: Development perspectives for the methanization sector in Haute-Normandie. To understand methanization. Haute-Normandie Commission of expertise on methanization

    International Nuclear Information System (INIS)

    Convert, Mathilde

    2012-10-01

    A first report proposes an analysis of the situation of methanization installations in the Haute-Normandie region while recalling the national context. It briefly reports an analysis and assessment of waste flows, processed effluents, by-products and biomass displaying an energetic potential. It describes methanization installations by addressing the different steps of the methanization process, by presenting the different digestion indicators, by briefly evoking the issue of the return-to-soil of digestates, and by presenting various operational data. Financial aspects are then addressed (investments and subsidies, financial balance of farm-based and collective installations), and an overview of methanization projects in the region and development perspectives is proposed. The second report more precisely analyses development perspectives for the methanization sector in the region through a brief assessment of the methanizable organic substrate resource, a discussion of different associated challenges (energy, agronomic, environmental and societal), a discussion of development levers and brakes, and an analysis of competitions (related to the use of industrial by-products, between processing installations, and related to agricultural soils). Another document proposes an overview of various aspects of methanization: a tool for territorial development, regulatory framework, evolution of installations in the region, assets of methanization, and role of the regional commission of expertise on methanization

  18. Evaluation of Genetic Variation in Rice to Mitigate Methane Emissions

    Science.gov (United States)

    Agriculture is recognized as a significant contributor to greenhouse gas emissions (GHGE) globally. Paddy rice is a significant source of methane emissions. Methane accounts for about 11% of all U.S. GHGE and it is ~25 times more potent in global warming potential than carbon dioxide. Research has s...

  19. Factors Controlling Methane in Arctic Lakes of Southwest Greenland

    Science.gov (United States)

    2016-01-01

    We surveyed 15 lakes during the growing season of 2014 in Arctic lakes of southwest Greenland to determine which factors influence methane concentrations in these systems. Methane averaged 2.5 μmol L-1 in lakes, but varied a great deal across the landscape with lakes on older landscapes farther from the ice sheet margin having some of the highest values of methane reported in lakes in the northern hemisphere (125 μmol L-1). The most important factors influencing methane in Greenland lakes included ionic composition (SO4, Na, Cl) and chlorophyll a in the water column. DOC concentrations were also related to methane, but the short length of the study likely underestimated the influence and timing of DOC on methane concentrations in the region. Atmospheric methane concentrations are increasing globally, with freshwater ecosystems in northern latitudes continuing to serve as potentially large sources in the future. Much less is known about how freshwater lakes in Greenland fit in the global methane budget compared to other, more well-studied areas of the Arctic, hence our work provides essential data for a more complete view of this rapidly changing region. PMID:27454863

  20. Bioelectrochemical approach for control of methane emission from wetlands.

    Science.gov (United States)

    Liu, Shentan; Feng, Xiaojuan; Li, Xianning

    2017-10-01

    To harvest electricity and mitigate methane emissions from wetlands, a novel microbial fuel cell coupled constructed wetland (MFC-CW) was assembled with an anode placing in the rhizosphere and a cathode on the water surface. Plant-mediated methane accounted for 71-82% of the total methane fluxes. The bioanode served as an inexhaustible source of electron acceptors and resulted in reduced substantial methane emissions owing to electricigens outcompeting methanogens for carbon and electrons when substrate was deficient. However, when supplying sufficient organic carbon, both electricity and methane increased, indicating that electrogenesis and methanogenesis could co-exist in harmony. Direct methane emission (diffusion/ebullition) and plant-mediated methane emission were affected by operating conditions. Methanogenesis was significantly suppressed (∼98%) at HRT of 96h and with external resistance of 200Ω, accompanied with improved coulombic efficiency of 14.9% and current density of 187mA/m 2 . Contrarily, change of electrode polarity in the rhizosphere led to more methane efflux. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Predicting methane emission of dairy cows using milk composition

    NARCIS (Netherlands)

    Gastelen, van Sanne

    2017-01-01

    Enteric methane (CH4) is produced as a result of microbial fermentation of feed components in the gastrointestinal tract of ruminant livestock. Methane has no nutritional value for the animal and is predominately released into the environment through eructation and breath.

  2. Large tundra methane burst during onset of freezing

    DEFF Research Database (Denmark)

    Mastepanov, Mikhail; Sigsgaard, Charlotte; Dlugokencky, Edward J.

    2008-01-01

    of global atmospheric methane concentrations indicate that the observed early winter emission burst improves the agreement between the simulated seasonal cycle and atmospheric data from latitudes north of 60N. Our findings suggest that permafrost-associated freeze-in bursts of methane missions from tundra...

  3. Martian Atmospheric Methane Plumes from Meteor Shower Infall: A Hypothesis

    Science.gov (United States)

    Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.

    2016-01-01

    Methane plumes in the martian atmosphere have been detected using Earth-based spectroscopy, the Planetary Fourier Spectrometer on the ESA Mars Express mission, and the NASA Mars Science Laboratory. The methane's origin remains a mystery, with proposed sources including volcanism, exogenous sources like impacts and interplanetary dust, aqueous alteration of olivine in the presence of carbonaceous material, release from ancient deposits of methane clathrates, and/or biological activity. To date, none of these phenomena have been found to reliably correlate with the detection of methane plumes. An additional source exists, however: meteor showers could generate martian methane via UV pyrolysis of carbon-rich infall material. We find a correlation between the dates of Mars/cometary orbit encounters and detections of methane on Mars. We hypothesize that cometary debris falls onto Mars during these interactions, depositing freshly disaggregated meteor shower material in a regional concentration. The material generates methane via UV photolysis, resulting in a localized "plume" of short-lived methane.

  4. Methane Steam Reforming Kinetics for a Rhodium-Based Catalyst

    DEFF Research Database (Denmark)

    Jakobsen, Jon Geest; Jakobsen, M.; Chorkendorff, Ib

    2010-01-01

    Methane steam reforming is the key reaction to produce synthesis gas and hydrogen at the industrial scale. Here the kinetics of methane steam reforming over a rhodium-based catalyst is investigated in the temperature range 500-800 A degrees C and as a function of CH4, H2O and H-2 partial pressures...

  5. Enhanced Microbial Pathways for Methane Production from Oil Shale

    Energy Technology Data Exchange (ETDEWEB)

    Paul Fallgren

    2009-02-15

    Methane from oil shale can potentially provide a significant contribution to natural gas industry, and it may be possible to increase and continue methane production by artificially enhancing methanogenic activity through the addition of various substrate and nutrient treatments. Western Research Institute in conjunction with Pick & Shovel Inc. and the U.S. Department of Energy conducted microcosm and scaled-up reactor studies to investigate the feasibility and optimization of biogenic methane production from oil shale. The microcosm study involving crushed oil shale showed the highest yield of methane was produced from oil shale pretreated with a basic solution and treated with nutrients. Incubation at 30 C, which is the estimated temperature in the subsurface where the oil shale originated, caused and increase in methane production. The methane production eventually decreased when pH of the system was above 9.00. In the scaled-up reactor study, pretreatment of the oil shale with a basic solution, nutrient enhancements, incubation at 30 C, and maintaining pH at circumneutral levels yielded the highest rate of biogenic methane production. From this study, the annual biogenic methane production rate was determined to be as high as 6042 cu. ft/ton oil shale.

  6. Lost lake - restoration of a Carolina bay

    Energy Technology Data Exchange (ETDEWEB)

    Hanlin, H.G.; McLendon, J.P. [Univ. of South Carolina, Aiken, SC (United States). Dept. of Biology and Geology; Wike, L.D. [Univ. of South Carolina, Aiken, SC (United States). Dept. of Biology and Geology]|[Westinghouse Savannah River Co., Aiken, SC (United States). Savannah River Technology Center; Dietsch, B.M. [Univ. of South Carolina, Aiken, SC (United States). Dept. of Biology and Geology]|[Univ. of Georgia, Aiken, SC (United States)

    1994-09-01

    Carolina bays are shallow wetland depressions found only on the Atlantic Coastal Plain. Although these isolated interstream wetlands support many types of communities, they share the common features of having a sandy margin, a fluctuating water level, an elliptical shape, and a northwest to southeast orientation. Lost Lake, an 11.3 hectare Carolina bay, was ditched and drained for agricultural production before establishment of the Savannah River Site in 1950. Later it received overflow from a seepage basin containing a variety of chemicals, primarily solvents and some heavy metals. In 1990 a plan was developed for the restoration of Lost Lake, and restoration activities were complete by mid-1991. Lost Lake is the first known project designed for the restoration and recovery of a Carolina bay. The bay was divided into eight soil treatment zones, allowing four treatments in duplicate. Each of the eight zones was planted with eight species of native wetland plants. Recolonization of the bay by amphibians and reptiles is being evaluated by using drift fences with pitfall traps and coverboard arrays in each of the treatment zones. Additional drift fences in five upland habitats were also established. Hoop turtle traps, funnel minnow traps, and dip nets were utilized for aquatic sampling. The presence of 43 species common to the region has been documented at Lost Lake. More than one-third of these species show evidence of breeding populations being established. Three species found prior to the restoration activity and a number of species common to undisturbed Carolina bays were not encountered. Colonization by additional species is anticipated as the wetland undergoes further succession.

  7. Mapping Oyster Reef Habitats in Mobile Bay

    Science.gov (United States)

    Bolte, Danielle

    2011-01-01

    Oyster reefs around the world are declining rapidly, and although they haven t received as much attention as coral reefs, they are just as important to their local ecosystems and economies. Oyster reefs provide habitats for many species of fish, invertebrates, and crustaceans, as well as the next generations of oysters. Oysters are also harvested from many of these reefs and are an important segment of many local economies, including that of Mobile Bay, where oysters rank in the top five commercial marine species both by landed weight and by dollar value. Although the remaining Mobile Bay oyster reefs are some of the least degraded in the world, projected climate change could have dramatic effects on the health of these important ecosystems. The viability of oyster reefs depends on water depth and temperature, appropriate pH and salinity levels, and the amount of dissolved oxygen in the water. Projected increases in sea level, changes in precipitation and runoff patterns, and changes in pH resulting from increases in the amount of carbon dioxide dissolved in the oceans could all affect the viability of oyster reefs in the future. Human activities such as dredging and unsustainable harvesting practices are also adversely impacting the oyster reefs. Fortunately, several projects are already under way to help rebuild or support existing or previously existing oyster reefs. The success of these projects will depend on the local effects of climate change on the current and potential habitats and man s ability to recognize and halt unsustainable harvesting practices. As the extent and health of the reefs changes, it will have impacts on the Mobile Bay ecosystem and economy, changing the resources available to the people who live there and to the rest of the country, since Mobile Bay is an important national source of seafood. This project identified potential climate change impacts on the oyster reefs of Mobile Bay, including the possible addition of newly viable

  8. Algae Reefs in Shark Bay, Western Australia, Australia

    Science.gov (United States)

    1990-01-01

    Numerous algae reefs are seen in Shark Bay, Western Australia, Australia (26.0S, 113.5E) especially in the southern portions of the bay. The south end is more saline because tidal flow in and out of the bay is restricted by sediment deposited at the north and central end of the bay opposite the mouth of the Wooramel River. This extremely arid region produces little sediment runoff so that the waters are very clear, saline and rich in algae.

  9. Atmospheric Ozone and Methane in a Changing Climate

    Directory of Open Access Journals (Sweden)

    Ivar S. A. Isaksen

    2014-07-01

    Full Text Available Ozone and methane are chemically active climate-forcing agents affected by climate–chemistry interactions in the atmosphere. Key chemical reactions and processes affecting ozone and methane are presented. It is shown that climate-chemistry interactions have a significant impact on the two compounds. Ozone, which is a secondary compound in the atmosphere, produced and broken down mainly in the troposphere and stratosphre through chemical reactions involving atomic oxygen (O, NOx compounds (NO, NO2, CO, hydrogen radicals (OH, HO2, volatile organic compounds (VOC and chlorine (Cl, ClO and bromine (Br, BrO. Ozone is broken down through changes in the atmospheric distribution of the afore mentioned compounds. Methane is a primary compound emitted from different sources (wetlands, rice production, livestock, mining, oil and gas production and landfills.Methane is broken down by the hydroxyl radical (OH. OH is significantly affected by methane emissions, defined by the feedback factor, currently estimated to be in the range 1.3 to 1.5, and increasing with increasing methane emission. Ozone and methane changes are affected by NOx emissions. While ozone in general increase with increases in NOx emission, methane is reduced, due to increases in OH. Several processes where current and future changes have implications for climate-chemistry interactions are identified. It is also shown that climatic changes through dynamic processes could have significant impact on the atmospheric chemical distribution of ozone and methane, as we can see through the impact of Quasi Biennial Oscillation (QBO. Modeling studies indicate that increases in ozone could be more pronounced toward the end of this century. Thawing permafrost could lead to important positive feedbacks in the climate system. Large amounts of organic material are stored in the upper layers of the permafrost in the yedoma deposits in Siberia, where 2 to 5% of the deposits could be organic material

  10. Chesapeake bay watershed land cover data series

    Science.gov (United States)

    Irani, Frederick M.; Claggett, Peter

    2010-01-01

    To better understand how the land is changing and to relate those changes to water quality trends, the USGS EGSC funded the production of a Chesapeake Bay Watershed Land Cover Data Series (CBLCD) representing four dates: 1984, 1992, 2001, and 2006. EGSC will publish land change forecasts based on observed trends in the CBLCD over the coming year. They are in the process of interpreting and publishing statistics on the extent, type and patterns of land cover change for 1984-2006 in the Bay watershed, major tributaries and counties.

  11. STS-98 Destiny in Atlantis's payload bay

    Science.gov (United States)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. -- The U.S. Laboratory Destiny rests once again in Atlantis'''s payload bay, at Launch Pad 39A. Closing of the payload bay doors is imminent. Destiny, a key element in the construction of the International Space Station, is 28 feet long and weighs 16 tons. This research and command-and-control center is the most sophisticated and versatile space laboratory ever built. It will ultimately house a total of 23 experiment racks for crew support and scientific research. Destiny will be launched Feb. 7 on STS-98, the seventh construction flight to the ISS.

  12. Sulfate reduction and anaerobic methane oxidation in Black Sea sediments

    DEFF Research Database (Denmark)

    Jørgensen, BB; Weber, A.; Zopfi, J.

    2001-01-01

    Beyond the shelf break at ca. 150 m water depth, sulfate reduction is the only important process of organic matter oxidation in Black Sea sediments from the surface down to the sulfate-methane transition at 2-4 m depth. Sulfate reduction rates were measured experimentally with (SO42-)-S-35...... the process was very sluggish with turnover times of methane within the sulfate-methane transition zone of 20 yr or more. (C) 2001 Elsevier Science Ltd. All rights reserved.Beyond the shelf break at ca. 150 m water depth, sulfate reduction is the only important process of organic matter oxidation in Black Sea...... oxidation accounted for 7-11% of the total sulfate reduction in slope and deep-sea sediments. Although this methane-driven sulfate reduction shaped the entire sulfate gradient, it was only equivalent to the sulfate reduction in the uppermost 1.5 cm of surface sediment. Methane oxidation was complete, yet...

  13. Mars methane rises and falls with the seasons

    Science.gov (United States)

    Hand, Eric

    2018-01-01

    On Earth, atmospheric methane is a prominent sign of life. On Mars, the story is more complicated. Trace detections of methane, alongside glimpses of larger spikes, have fueled debates about biological and nonbiological sources of the gas. Now, NASA scientists have announced a new twist in the tale: Methane regularly rises to a peak in late northern summer in a seasonal pattern. The swings are larger than can be explained by the planet's seasonal freeze-thaw cycles. The wiggles are a mystery within a larger mystery: claims of methane spikes an order of magnitude or two higher than the background. Some scientists say meteor showers could be responsible, by depositing carbonaceous material in the atmosphere that reacts to form methane. A close encounter on 24 January with debris from a comet could provide a chance to test the hypothesis.

  14. Status and potential of bio-methane fuel

    International Nuclear Information System (INIS)

    2008-01-01

    This document first indicates and describes the various bio-methane production processes which can be implemented on a short term (use of organic wastes or effluents), on a medium term (from energetic crops) and on a longer term (gasification). It discusses and assesses the potential production of bio-methane fuel from different sources and processes. It describes the steps of the production of bio-methane fuel from biogas, with notably biogas refinement to produce bio-methane through three processes (de-carbonation, desulfurization, dehydration). Cost productions are assessed. Expected technology advances are evoked. Finally, the authors outline the contribution of bio-methane in the limitation of greenhouse gas emissions in the transport sector

  15. Fundamental challenges to methane recovery from gas hydrates

    Science.gov (United States)

    Servio, P.; Eaton, M.W.; Mahajan, D.; Winters, W.J.

    2005-01-01

    The fundamental challenges, the location, magnitude, and feasibility of recovery, which must be addressed to recover methane from dispersed hydrate sources, are presented. To induce dissociation of gas hydrate prior to methane recovery, two potential methods are typically considered. Because thermal stimulation requires a large energy input, it is less economically feasible than depressurization. The new data will allow the study of the effect of pressure, temperature, diffusion, porosity, tortuosity, composition of gas and water, and porous media on gas-hydrate production. These data also will allow one to improve existing models related to the stability and dissociation of sea floor hydrates. The reproducible kinetic data from the planned runs together with sediment properties will aid in developing a process to economically recover methane from a potential untapped hydrate source. The availability of plentiful methane will allow economical and large-scale production of methane-derived clean fuels to help avert future energy crises.

  16. Clumped isotope effects during OH and Cl oxidation of methane

    DEFF Research Database (Denmark)

    Whitehill, Andrew R.; Joelsson, Lars Magnus T.; Schmidt, Johan Albrecht

    2017-01-01

    A series of experiments were carried out to determine the clumped (13CH3D) methane kinetic isotope effects during oxidation of methane by OH and Cl radicals, the major sink reactions for atmospheric methane. Experiments were performed in a 100 L quartz photochemical reactor, in which OH...... was produced from the reaction of O(1D) (from O3 photolysis) with H2O, and Cl was from photolysis of Cl2. Samples were taken from the reaction cell and analyzed for methane (12CH4, 12CH3D, 13CH4, 13CH3D) isotopologue ratios using tunable infrared laser direct absorption spectroscopy. Measured kinetic isotope...... effects for singly substituted species were consistent with previous experimental studies. For doubly substituted methane, 13CH3D, the observed kinetic isotope effects closely follow the product of the kinetic isotope effects for the 13C and deuterium substituted species (i.e., 13,2KIE = 13KIE × 2KIE...

  17. Sediment Trapping by Dams Creates Methane Emission Hot Spots

    DEFF Research Database (Denmark)

    Maeck, Andreas; DelSontro, Tonya; McGinnis, Daniel F.

    2013-01-01

    Inland waters transport and transform substantial amounts of carbon and account for similar to 18% of global methane emissions. Large reservoirs with higher areal methane release rates than natural waters contribute significantly to freshwater emissions. However, there are millions of small dams...... worldwide that receive and trap high loads of organic carbon and can therefore potentially emit significant amounts of methane to the atmosphere. We evaluated the effect of damming on methane emissions in a central European impounded river. Direct comparison of riverine and reservoir reaches, where...... sedimentation in the latter is increased due to trapping by dams, revealed that the reservoir reaches are the major source of methane emissions (similar to 0.23 mmol CH4 m(-2) d(-1) vs similar to 19.7 mmol CH4 m(-2) d(-1), respectively) and that areal emission rates far exceed previous estimates for temperate...

  18. Wide area methane emissions mapping with airborne IPDA lidar

    Science.gov (United States)

    Bartholomew, Jarett; Lyman, Philip; Weimer, Carl; Tandy, William

    2017-08-01

    Methane emissions from natural gas production, storage, and transportation are potential sources of greenhouse gas emissions. Methane leaks also constitute revenue loss potential from operations. Since 2013, Ball Aerospace has been developing advanced airborne sensors using integrated path differential absorption (IPDA) LIDAR instrumentation to identify methane, propane, and longer-chain alkanes in the lowest region of the atmosphere. Additional funding has come from the U.S. Department of Transportation, Pipeline and Hazardous Materials Administration (PHMSA) to upgrade instrumentation to a broader swath coverage of up to 400 meters while maintaining high spatial sampling resolution and geolocation accuracy. Wide area coverage allows efficient mapping of emissions from gathering and distribution networks, processing facilities, landfills, natural seeps, and other distributed methane sources. This paper summarizes the benefits of advanced instrumentation for aerial methane emission mapping, describes the operating characteristics and design of this upgraded IPDA instrumentation, and reviews technical challenges encountered during development and deployment.

  19. New Petrochemical Processes Based on Direct Conversion of Methane

    Directory of Open Access Journals (Sweden)

    Faraguna F.

    2015-01-01

    Full Text Available Petrochemistry is a branch of chemistry and chemical engineering that studies reactions and processes of the transformation of petroleum derivatives and natural gas into useful petrochemicals. In its beginning, petrochemistry, or rather the organic chemical industry, was based on the acetylene and Reppe chemistry. The main raw materials of the petrochemical industry nowadays are olefins and aromatic hydrocarbons, with a pronounced tendency toward development of new processes and higher usage of syngas, methane and other alkanes. Here, the reactions and new processes of direct conversion of methane into more valuable petrochemicals are reviewed. Reactions of partial oxidation of methane, dehydroaromatization of methane, oxidative and non-oxidative coupling of methane to higher hydrocarbons are also described and discussed.

  20. Spatial hierarchical Bayes estimation of mean years of schooling

    Science.gov (United States)

    Wahyuni, Dwi A. S.; Wage, Sutarman; Darnius, Open

    2018-01-01

    A spatial hierarchical bayes for estimating mean years of schooling district level is proposed. We developed spatial hierarchical bayes within a Monte Carlo simulation study with R software. The simulation generated posterior distribution invers gamma. The spatial correlation used rook contiguity for each district. Hierarchical bayes method with spatial weighted provides smaller relative bias and relative root mean square.

  1. Chondrichthyan occurrence and abundance trends in False Bay ...

    African Journals Online (AJOL)

    Commercial fishing in False Bay, South Africa, began in the 1600s. Today chondrichthyans are regularly taken in fisheries throughout the bay. Using a combination of catch, survey and life history data, the occurrence and long-term changes in populations of chondrichthyans in False Bay are described. Analyses of time ...

  2. Extinguishing methane burning in the goaf. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Belik, I.P.; Romanchuk, A.L.; Grekov, A.S.

    1982-09-01

    The paper evaluates methods for extinguishing burning methane in the goaf of gassy coal mines with intensive methane emission. Three cases of fire extinguishing using water, fire extinguishing foams and powders are analyzed. Analyses show that use of water and foams under conditions of intensive air flow through the goaf is inefficient. The same situation exists when a fire center develops at a distance of at least 20 to 40 m from a mine roadway. When an intensive air stream (leak) ventilates the goaf, use of a blower which forces a fire extinguishing powder into the goaf permits a fire to be extinguished in a short time. Use of the P-2AP powder and the 'Vikhr' blower for fire fighting should be combined with pressing water into the goaf for reducing rock temperature along with fire extinguishing foam which insulates the fire center from oxygen. Foam and water are forced into the goaf by a system of boreholes. Development of a fire, coal combustion and effects of fire fighting are controlled by measurements of carbon monoxide in the mine air. Two schemes of fire fighting at two coal faces in Donbass mines are given. Safety aspects of fire extinguishing are evaluated.

  3. Plasma Thermal Conversion of Methane to Acetylene

    International Nuclear Information System (INIS)

    Fincke, James Russell; Anderson, Raymond Paul; Hyde, Timothy Allen; Detering, Brent Alan; Wright, Randy Ben; Bewley, Randy Lee; Haggard, Delon C; Swank, William David

    2002-01-01

    This paper describes a re-examination of a known process for the direct plasma thermal conversion of methane to acetylene. Conversion efficiencies (% methane converted) approached 100% and acetylene yields in the 90-95% range with 2-4% solid carbon production were demonstrated. Specificity for acetylene was higher than in prior work. Improvements in conversion efficiency, yield, and specificity were due primarily to improved injector design and reactant mixing, and minimization of temperature gradients and cold boundary layers. At the 60-kilowatt scale cooling by wall heat transfer appears to be sufficient to quench the product stream and prevent further reaction of acetylene resulting in the formation of heavier hydrocarbon products or solid carbon. Significantly increasing the quenching rate by aerodynamic expansion of the products through a converging-diverging nozzle led to a reduction in the yield of ethylene but had little effect on the yield of other hydrocarbon products. While greater product selectivity for acetylene has been demonstrated, the specific energy consumption per unit mass of acetylene produced was not improved upon. A kinetic model that includes the reaction mechanisms resulting in the formation of acetylene and heavier hydrocarbons, through benzene, is described

  4. An innovative membrane bioreactor for methane biohydroxylation.

    Science.gov (United States)

    Pen, N; Soussan, L; Belleville, M-P; Sanchez, J; Charmette, C; Paolucci-Jeanjean, D

    2014-12-01

    In this study, a membrane bioreactor (MBR) was developed for efficient, safe microbial methane hydroxylation with Methylosinus trichosporium OB3b. This innovative MBR, which couples a bioreactor with two gas/liquid macroporous membrane contactors supplying the two gaseous substrates (methane and oxygen) was operated in fed-batch mode. The feasibility and the reproducibility of this new biohydroxylation process were first demonstrated. The mass transfer within this MBR was twice that observed in a batch reactor in similar conditions. The productivity reached with this MBR was 75±25mgmethanol(gdrycell)(-1)h(-1). Compared to the literature, this value is 35times higher than that obtained with the only other fed-batch membrane bioreactor reported, which was run with dense membranes, and is comparable to those obtained with bioreactors fed by bubble-spargers. However, in the latter case, an explosive gas mixture can be formed, a problem that is avoided with the MBR. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Measured stimulated Raman gain in methane

    International Nuclear Information System (INIS)

    Lopert, R.B.

    1983-01-01

    This report is about the stimulated Raman effect in methane due to the nu 1 vibration. For various gas pressures between 150 torr and 30 atm, the Raman lineshape function was both experimentally measured and synthesized using a computer model. The stimulated Raman gain was measured by sending a pump laser beam provided by an argon-ion laser and a weak probe beam provided by a tunable dye laser through a cell of methane gas. The stimulated Raman effect caused some of the energy from the pump beam to be transferred to the probe beam. The intensity of the pump beam was low so the gain of the probe beam was on the order of parts per million. A two detector arrangement and a differential amplifier system that had a feedback loop to balance the detectors was constructed to measure the small gains. A detailed description of this detection system that was able to measure gains as small as 0.2 parts per million is provided

  6. Carbon dioxide emissions in a methane economy

    Energy Technology Data Exchange (ETDEWEB)

    Ausubel, J.H.; Gruebler, A.; Nakicenovic, N.

    1988-06-01

    Increasing reliance on natural gas (methane) to meet global energy demands holds implications for atmospheric CO/sub 2/ concentrations. Analysis of these implications is presented, based on a logistic substitution model viewing energy technologies like biological species invading an econiche and substituting in case of superiority for existing species. This model suggests gas will become the dominant energy source and remain so for 50 years, peaking near 70 percent of world supply. Two scenarios of energy demand are explored, one holding per capita consumption at current levels, the second raising the global average in the year 2100 to the current U.S. level. In the first ('efficiency') scenario concentrations peak about 450 ppm, while in the second ('long wave') they near 600 ppm. Although projected CO/sub 2/ concentrations in a 'methane economy' are low in relation to other scenarios, the projections confirm that global climate warming is likely to be a major planetary concern throughout the twenty-first century. A second finding is that data on past growth of world per capita energy consumption group neatly into two pulses consistent with longwave theories in economics. 40 refs., 11 figs., 3 tabs.

  7. Coalbed Methane prospect of Jamalganj Coalfield Bangladesh

    International Nuclear Information System (INIS)

    Imam, M. Badrul; Rahman, M.; Akhtar, Syed Humayun

    2002-01-01

    Five major Gondwana coalfields have been discovered in the half-graben type basins in the subsurface in the Precambrian platform area of the Northwest Bangladesh. The Jamalganj coalfields with an estimated reserve of about 1053 millions tons of coal, has seven coal seams in the depth range between 640 to 1158m below the ground surface. Compared to the other coalfields of the area, with coal occurring at 150 to 500m depth, Jamalganj coal is considered to be too deep to be exploited by conventional underground or open pit mining. Instead, developing coal bed methane from Jamalganj coalfield may be considered as a viable option for its exploitation. The positive factors of Jamalganj coal bed methane development include high net thickness of coal with at least one very thick (40m+) and widely developed seam, coal seam burial depth within optimum range, large coal reserves, indication of significant gas content from drilling data, and poor permeability in the rocks above and surrounding the coal layers. The thickest seam III can be primary target for CBM development especially where it combines with seam IV in the eastern part of coalfield. However, there are a number of unknown factors like actual gas content of coal, permeability, and in-seam pressure that need to be evaluated before deciding the viability of the project. An initial attempt to collect these base line data should include drilling test well or wells in the primary target area where seam III is most thick and widely developed. (author)

  8. Molecular spin conversion in solid deuterated methane.

    Science.gov (United States)

    Stachowiak, Piotr

    2011-02-28

    The spin conversion of methane molecules in pure deuterated methane crystals and CD(4)-Kr solid solution for a wide range of concentrations of krypton was investigated in the temperature range 1.5-10 K. The experiment was performed by use of a steady-state heat flow experimental setup for determination of the thermal conductivity, utilized in an unconventional way. The obtained results were discussed in the frame of the spin conversion model taking into account direct one-phonon processes and indirect librationally-activated processes. It was found that the conversion, both for pure and krypton doped crystals, is dominated by the one-phonon mechanism. However, the importance of the indirect processes increases rapidly with the temperature. The obtained results indicate that the krypton admixture does not change the values of energy levels of the spin-librational (spin-rotational) spectrum of the crystal. The presence of Kr in the structure of CD(4) enhances the intensity of the direct one-phonon spin conversion processes and weakens the indirect librationally-activated ones.

  9. [The Trace Methane Sensor Based on TDLAS-WMS].

    Science.gov (United States)

    Liu, Yang; Wu, Jia-nan; Chen, Mei-mei; Yang, Xin-hua; Chen, Chen

    2016-01-01

    Methane is a colorless, odorless, flammable and explosive gas, which not only is the cause to induce significant security risk in coal mining operation, but also one of the important greenhouse gases, so the monitoring of methane is extremely critical. A trace methane gas sensor is designed and developed using the combination of tunable diode laser absorption spectroscopy (TDLAS) and wavelength modulation spectroscopy (WMS) detection technology, which is based on the methane R(3) absorption branch in 2v3 second harmonic band. Through tuning parameters -0.591 cm(-1) x K(-1), using the method that change the working temperature of distributed feedback (DFB) laser to obtain the best absorption wavelength of methane at 1.654 μm. When the mid-wavelength of DFB laser is selected, the appropriate emitting intension can be obtained via adjusting the amplitude of inject current of DFB laser. Meanwhile, combining the frequency modulation technology to move the bandwidth of detection signal from low frequency to high frequency to reduce the 1/f noise. With aspect to the optical structure, utilizing herriott cell with 76 m effective optical path to guarantee the detection of trace methane is successful. Utilizing the proposed trace methane sensor to extract the second harmonic signal of detected methane in the range of 50 to 5 000 μmol x mol(-1), and adopting minimum mean square error criterion to fit the relationship between methane concentration and signal noise ratio, harmonic peak signal and methane concentration, respectively. In addition, the minimum detection limit is 1.4 μmol x mol(-1). The experiment results show the symmetry of harmonic waveform is good, no intensity modulation, and the factor of intensity-modulated impacts on harmonic detection is eliminated.

  10. The interaction of climate change and methane hydrates

    Science.gov (United States)

    Ruppel, Carolyn D.; Kessler, John D.

    2017-01-01

    Gas hydrate, a frozen, naturally-occurring, and highly-concentrated form of methane, sequesters significant carbon in the global system and is stable only over a range of low-temperature and moderate-pressure conditions. Gas hydrate is widespread in the sediments of marine continental margins and permafrost areas, locations where ocean and atmospheric warming may perturb the hydrate stability field and lead to release of the sequestered methane into the overlying sediments and soils. Methane and methane-derived carbon that escape from sediments and soils and reach the atmosphere could exacerbate greenhouse warming. The synergy between warming climate and gas hydrate dissociation feeds a popular perception that global warming could drive catastrophic methane releases from the contemporary gas hydrate reservoir. Appropriate evaluation of the two sides of the climate-methane hydrate synergy requires assessing direct and indirect observational data related to gas hydrate dissociation phenomena and numerical models that track the interaction of gas hydrates/methane with the ocean and/or atmosphere. Methane hydrate is likely undergoing dissociation now on global upper continental slopes and on continental shelves that ring the Arctic Ocean. Many factors—the depth of the gas hydrates in sediments, strong sediment and water column sinks, and the inability of bubbles emitted at the seafloor to deliver methane to the sea-air interface in most cases—mitigate the impact of gas hydrate dissociation on atmospheric greenhouse gas concentrations though. There is no conclusive proof that hydrate-derived methane is reaching the atmosphere now, but more observational data and improved numerical models will better characterize the climate-hydrate synergy in the future.

  11. Ground and Airborne Methane Measurements Using Optical Parametric Amplifiers

    Science.gov (United States)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Abshire, James Brice; Dawsey, Martha; Ramanathan, Anand

    2011-01-01

    We report on ground and airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). The technique has been used to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planetary bodies. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Carbon and methane emissions from land are expected to increase as permafrost melts exposing millennial-age carbon stocks to respiration (aerobic-CO2 and anaerobic-CH4) and fires. Methane emissions from c1athrates in the Arctic Ocean and on land are also likely to respond to climate warming. However, there is considerable uncertainty in present Arctic flux levels, as well as how fluxes will change with the changing environment. For Mars, methane measurements are of great interest because of its potential as a strong biogenic marker. A remote sensing instrument that can measure day and night over all seasons and latitudes can localize sources of biogenic gas plumes produced by subsurface chemistry or biology, and aid in the search for extra-terrestrial life. In this paper we report on remote sensing measurements of methane using a high peak power, widely tunable optical parametric generator (OPG) operating at 3.3 micrometers and 1.65 micrometers. We have demonstrated detection of methane at 3.3 micrometers and 1650 nanometers in an open path and compared them to accepted standards. We also report on preliminary airborne demonstration of methane measurements at 1.65 micrometers.

  12. Ecosystem and physiological controls over methane production in northern wetlands

    Science.gov (United States)

    Valentine, David W.; Holland, Elisabeth A.; Schimel, David S.

    1994-01-01

    Peat chemistry appears to exert primary control over methane production rates in the Canadian Northern Wetlands Study (NOWES) area. We determined laboratory methane production rate potentials in anaerobic slurries of samples collected from a transect of sites through the NOWES study area. We related methane production rates to indicators of resistance to microbial decay (peat C: N and lignin: N ratios) and experimentally manipulated substrate availability for methanogenesis using ethanol (EtOH) and plant litter. We also determined responses of methane production to pH and temperature. Methane production potentials declined along the gradient of sites from high rates in the coastal fens to low rates in the interior bogs and were generally highest in surface layers. Strong relationships between CH4 production potentials and peat chemistry suggested that methanogenesis was limited by fermentation rates. Methane production at ambient pH responded strongly to substrate additions in the circumneutral fens with narrow lignin: N and C: N ratios (delta CH4/delta EtOH = 0.9-2.3 mg/g) and weakly in the acidic bogs with wide C: N and lignin: N ratios (delta CH4/delta EtOH = -0.04-0.02 mg/g). Observed Q(sub 10) values ranged from 1.7 to 4.7 and generally increased with increasing substrate availability, suggesting that fermentation rates were limiting. Titration experiments generally demonstrated inhibition of methanogenesis by low pH. Our results suggest that the low rates of methane emission observed in interior bogs during NOWES likely resulted from pH and substrate quality limitation of the fermentation step in methane production and thus reflect intrinsically low methane production potentials. Low methane emission rates observed during NOWES will likely be observed in other northern wetland regions with similar vegetation chemistry.

  13. The Real Difference between Biotic and Abiotic Methane

    Science.gov (United States)

    Cao, X.; Bao, H.; Peng, Y.

    2017-12-01

    Methane has both biotic and abiotic origins, and the identification of these two origins has important implications not only in understanding terrestrial processes but also in searching for extraterrestrial life. Carbon and hydrogen isotopes in methane have been used to identify certain biosignatures, but such efforts often suffer from ambiguity. Recent advancement in our capability in measuring multiply substituted isotopologues of methane (i.e. 13CDH3 and 12CD2H2) has found large 12CD2H2 depletion in abiotic methane. Quantum tunneling has been proposed to account for the apparent abiotic signature. However, quantum tunneling is neither unique to abiotic processes nor consistent with the observed not-so-depleted hydrogen isotope composition. Here we constructed a general kinetic model for methane formation from CO2, and validated it by fitting its parameters to observed 13CDH3, 12CD2H2, and 12CDH3. Our model revealed that the fundamental difference between biotic and abiotic methane isotopic signatures is in the source of hydrogens during methane formation. Hydrogens in biotic methane originate from the stronger carbon-hydrogen and sulfur-hydrogen bonds, while hydrogens in abiotic methane originate from the much weaker metal-hydrogen adsorption bond. This hydrogen source difference results in abiotic methane being more depleted in 12CD2H2 than the biotic one. Our model also shows that the primary kinetic hydrogen isotope effect is at approximately 0.6 for both abiotic and biotic pathways, a normal value further nullifying the role of quantum tunneling. The active and exclusive shuttling of reduced hydrogen via strong chemical bonds like carbon-hydrogen and sulfur-hydrogen in coenzymes is proposed here to be a unique signature of life. In an ironic sense, it is the equilibrated hydrogen isotope composition in the hydrogen donors that distinguishes the living from the non-living.

  14. Methane Seepage on Mars: Where to Look and Why

    Science.gov (United States)

    Oehler, Dorothy Z.; Etiope, Giuseppe

    2017-12-01

    Methane on Mars is a topic of special interest because of its potential association with microbial life. The variable detections of methane by the Curiosity rover, orbiters, and terrestrial telescopes, coupled with methane's short lifetime in the martian atmosphere, may imply an active gas source in the planet's subsurface, with migration and surface emission processes similar to those known on Earth as "gas seepage." Here, we review the variety of subsurface processes that could result in methane seepage on Mars. Such methane could originate from abiotic chemical reactions, thermogenic alteration of abiotic or biotic organic matter, and ancient or extant microbial metabolism. These processes can occur over a wide range of temperatures, in both sedimentary and igneous rocks, and together they enhance the possibility that significant amounts of methane could have formed on early Mars. Methane seepage to the surface would occur preferentially along faults and fractures, through focused macro-seeps and/or diffuse microseepage exhalations. Our work highlights the types of features on Mars that could be associated with methane release, including mud-volcano-like mounds in Acidalia or Utopia; proposed ancient springs in Gusev Crater, Arabia Terra, and Valles Marineris; and rims of large impact craters. These could have been locations of past macro-seeps and may still emit methane today. Microseepage could occur through faults along the dichotomy or fractures such as those at Nili Fossae, Cerberus Fossae, the Argyre impact, and those produced in serpentinized rocks. Martian microseepage would be extremely difficult to detect remotely yet could constitute a significant gas source. We emphasize that the most definitive detection of methane seepage from different release candidates would be best provided by measurements performed in the ground or at the ground-atmosphere interface by landers or rovers and that the technology for such detection is currently available.

  15. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate.

    Science.gov (United States)

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-21

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d(-1)) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery.

  16. Zero valent iron significantly enhances methane production from waste activated sludge by improving biochemical methane potential rather than hydrolysis rate.

    Science.gov (United States)

    Liu, Yiwen; Wang, Qilin; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-05

    Anaerobic digestion has been widely applied for waste activated sludge (WAS) treatment. However, methane production from anaerobic digestion of WAS is usually limited by the slow hydrolysis rate and/or poor biochemical methane potential of WAS. This work systematically studied the effects of three different types of zero valent iron (i.e., iron powder, clean scrap and rusty scrap) on methane production from WAS in anaerobic digestion, by using both experimental and mathematical approaches. The results demonstrated that both the clean and the rusty iron scrap were more effective than the iron powder for improving methane production from WAS. Model-based analysis showed that ZVI addition significantly enhanced methane production from WAS through improving the biochemical methane potential of WAS rather than its hydrolysis rate. Economic analysis indicated that the ZVI-based technology for enhancing methane production from WAS is economically attractive, particularly considering that iron scrap can be freely acquired from industrial waste. Based on these results, the ZVI-based anaerobic digestion process of this work could be easily integrated with the conventional chemical phosphorus removal process in wastewater treatment plant to form a cost-effective and environment-friendly approach, enabling maximum resource recovery/reuse while achieving enhanced methane production in wastewater treatment system.

  17. Ignition-promoting effect of NO2 on methane, ethane and methane/ethane mixtures in a rapid compression machine

    NARCIS (Netherlands)

    Gersen, S.; Mokhov, A. V.; Darmeveil, J. H.; Levinsky, H. B.; Glarborg, P.

    2011-01-01

    Autoignition delay times of stoichiometric methane, ethane and methane/ethane mixtures doped with 100 and 270 ppm of NO2 have been measured in a RCM in the temperature range 900-1050 K and pressures from 25 to 50 bar. The measurements show that addition of NO2 to CH4/O-2/N-2/ Ar and

  18. Coupled models of free methane gas and anaerobic oxidation of methane : from core to regional scales. Geologica Ultraiectina (339)

    NARCIS (Netherlands)

    Mogollón, J.M.

    2011-01-01

    Methane is a potent greenhouse gas that is produced in marine sediments containing high amounts of degrading organic carbon. It is therefore not surprising that marine sediments contain vast amounts of methane (500-5000 gigatons) present in dissolved (aqueous), free gas (gaseous), and solid

  19. Methane-derived carbon flows through methane-oxidizing bacteria to higher trophic levels in aquatic systems

    NARCIS (Netherlands)

    Deines, P.; Bodelier, P.L.E.; Eller, G.

    2007-01-01

    Recent investigations have shown that biogenic methane can be a carbon source for macro invertebrates in freshwater food webs. Stable carbon isotopic signatures, used to infer an organism's food source, indicated that methane can play a major role in the nutrition of chironomid larvae. However, the

  20. Polyhydroxyalkanoates in waste activated sludge enhances anaerobic methane production through improving biochemical methane potential instead of hydrolysis rate

    Science.gov (United States)

    Wang, Qilin; Sun, Jing; Zhang, Chang; Xie, Guo-Jun; Zhou, Xu; Qian, Jin; Yang, Guojing; Zeng, Guangming; Liu, Yiqi; Wang, Dongbo

    2016-01-01

    Anaerobic sludge digestion is the main technology for sludge reduction and stabilization prior to sludge disposal. Nevertheless, methane production from anaerobic digestion of waste activated sludge (WAS) is often restricted by the poor biochemical methane potential and slow hydrolysis rate of WAS. This work systematically investigated the effect of PHA levels of WAS on anaerobic methane production, using both experimental and mathematical modeling approaches. Biochemical methane potential tests showed that methane production increased with increased PHA levels in WAS. Model-based analysis suggested that the PHA-based method enhanced methane production by improving biochemical methane potential of WAS, with the highest enhancement being around 40% (from 192 to 274 L CH4/kg VS added; VS: volatile solid) when the PHA levels increased from 21 to 143 mg/g VS. In contrast, the hydrolysis rate (approximately 0.10 d-1) was not significantly affected by the PHA levels. Economic analysis suggested that the PHA-based method could save $1.2/PE/y (PE: population equivalent) in a typical wastewater treatment plant (WWTP). The PHA-based method can be easily integrated into the current WWTP to enhance methane production, thereby providing a strong support to the on-going paradigm shift in wastewater management from pollutant removal to resource recovery.