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Sample records for covered lagoon methane

  1. SEASONAL EMISSIONS OF AMMONIA AND METHANE FROM A HOG WASTE LAGOON WITH BIOACTIVE COVER

    EPA Science Inventory

    The paper discusses the use of plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) to measure the flux of ammonia and methane from a hog waste lagoon before and after the installation of a bioactive cover. A computed tomography algorithm using a smoo...

  2. SEASONAL EMISSIONS OF AMMONIA AND METHANE FROM A HOG WASTE LAGOON WITH BIOACTIVE COVER

    EPA Science Inventory

    The paper discusses the use of plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) to measure the flux of ammonia and methane from a hog waste lagoon before and after the installation of a bioactive cover. A computed tomography algorithm using a smoo...

  3. Design of a covered lagoon methane recovery system for a flush dairy

    SciTech Connect

    Williams, D.W.; Moser, M.; Smith, J.

    1996-12-31

    A lagoon-type methane recovery system was designed for the Cal Poly Dairy, which milks 130 cows with a total population of 296 animals. Most of the herd is housed in freestall barns where the manure is deposited on concrete and flushed with fresh or recycled water to an existing lagoon with a volume of 19,300 cubic meters. The design includes a new, primary covered lagoon of 17,000 cubic meters volume. The floating cover will be made of very low density polyethylene (VLDPE), with an area of 4,500 square meters. The predicted output of the lagoon is an average of over 310 cubic meters of biogas per day containing 60 percent methane. The methane production from the covered lagoon is adequate to produce 18 to 24 kW on a continuous basis from the present cow population. In order to account for future herd size increases, a 40 kW engine generator was specified to operate in parallel with the utility system at a varying level of output controlled by the biogas supply. The non-economic benefits of this covered lagoon include the demonstration of its operation to the students and visitors at Cal Poly which in turn will serve the California Dairy Community. Odor control is the most important non-economic benefit. Conversion of volatile solids to biogas and recovery and use of the biogas limits odor to surrounding areas. The economic benefits of the methane recovery system include the approximately 160,000 kWh of electricity produced annually, worth almost $13,000. Financial analyses for the project showed a payback of 13.7 years with a 4% internal rate of return.

  4. Methane Dynamics in Sediments from Mangrove-dominated Costal Lagoons

    NASA Astrophysics Data System (ADS)

    Chuang, P. C.; Paytan, A.; Young, M. B.

    2014-12-01

    Porewater methane and sulfate concentrations from cored sediments have been measured in two coastal mangrove ecosystems (Celestún and Chelem Lagoons) on the Yucatán Peninsula, Mexico. Methane exists in shallow sediments while sulfate is not depleted and stable carbon isotopes of methane (-87.27‰ ~ -62.08‰) imply high methane fluxes/production rates below and within the cored sediment depths. The preliminary results from a transport-reaction model show that methane emitted to the water column from these sediments could be 17.8 mg m-2 d-1 in Celestún Lagoon and much higher (565 mg m-2 d-1) in Chelem Lagoon. Since the water depths are shallow (mostly less than 100 cm), the high fluxes of methane could contribute to the atmosphere. The objectives of this study will aim to understand the biogeochemical cycles for methane and sulfate in sediments. A numerical transport-reaction model will be applied to the sedimentary geochemical data (methane, sulfate, chloride, particulate organic carbon (POC) and stable carbon isotopes of headspace methane) from the two lagoons to estimate sulfate reduction, methane oxidation and production rates and advective methane fluxes. The modeled results will be used to discuss the role of methane from mangrove areas and their potential contribution to the global methane cycle.

  5. Nitrifier activity and diversity in swine lagoon covers

    USDA-ARS?s Scientific Manuscript database

    Ammonia emissions from swine waste lagoons pose an environmental challenge to current pork production practices. Semi-permeable lagoon covers limit ammonia emissions by minimizing the effect of wind on the lagoon surface. Additionally, semi-permeable covers may also act as an attachment site for b...

  6. Methane Emissions from Tropical Coastal Lagoons, Yucatan, Mexico

    NASA Astrophysics Data System (ADS)

    Young, M.; Paytan, A.; Herrera-Silveira, J.

    2003-12-01

    Tropical and sub-tropical wetlands are thought to be the dominant natural source of methane to the atmosphere, and the majority of tropical methane flux research has been carried out in freshwater environments. In order to obtain better estimates of methane emissions from tropical coastal environments, we are currently conducting a multi-year study of methane cycling and flux in three tropical coastal lagoons and associated mangrove ecosystems located on the Yucatan Peninsula in Mexico. Previous studies have shown that methane emissions from tropical coastal ecosystems are widely variable, and that these emissions can be quite high despite the presence of moderate to marine salinities. We measured surface water methane concentrations in two lagoons (Celestun and Chelem) during different seasons, as well as in a third, heavily polluted lagoon (Terminos), during the rainy season. Celestun lagoon has a distinct year-round salinity gradient (7-35 ppt) due to groundwater input, Terminos lagoon ranges from fresh water at the river entrances to marine in most of the lagoon area, and Chelem has a salinity range from marine to slightly hyper-saline (30-40 ppt). Diffusive methane flux to the atmosphere was calculated from surface water methane concentrations, using both sample-specific and average area wind speed measurements. Additionally, flux chambers were used to measure methane emissions from each of the lagoons during the rainy season. Calculated diffusive fluxes ranged from less than 1 mg CH4/m2/day up to 100 mg CH4/m2/day in all three lagoons, with the highest fluxes occurring in both areas of lower salinity and areas with known waste water discharge. However, measurements of bubble flux made using flux chambers were between 20 and 150 times greater than the diffusive flux calculated for the same locations. During the course of this study, it appears that the most significant bubble flux occurs in these lagoons during the rainy season. Observations and flux chamber

  7. Inhomogeneity of methane emissions from a dairy waste lagoon.

    PubMed

    Grant, Richard H; Boehm, Matthew T

    2015-11-01

    Methane (CH4) is the dominant greenhouse gas emitted by animal agriculture manure. Since the gas is relatively insoluble in water, it is concentrated in discrete bubbles that rise through waste lagoons and burst at the surface. This results in lagoon emissions that are inhomogeneous in both space and time. Emissions from a midwestern dairy waste lagoon were measured over 2 weeks to evaluate the spatial homogeneity of the source emissions and to compare two methods for measuring this inhomogeneous emission. Emissions were determined using an inverse dispersion model based on CH4 concentrations measured both by a single scanning tunable diode laser (TDL) aimed at a series of reflectors and by flame ionization detection (FID) gas chromatography on line-sampled air. Emissions were best estimated using scanned TDL concentrations over relatively short optical paths that collectively span the entire cross-wind width of the source, so as to provide both the best capture of discrete plumes from the bursting bubbles on the lagoon surface and the best detection of CH4 background concentrations. The lagoon emissions during the study were spatially inhomogeneous at hourly time scales. Partitioning the inhomogeneous source into two source regions reduced the estimated emissions of the overall lagoon by 57% but increased the variability. Consequently, it is important to assess the homogeneity of a source prior to measurements and final emissions calculation. Plans for measuring methane emissions from waste lagoons must take into account the spatial inhomogeneity of the source strength. The assumption of emission source homogeneity for a low-solubility gas such as CH4 emitted from an animal waste lagoon can result in significant emission overestimates. The entire breadth and length of the area source must be measured, preferably with multiple optical paths, for the detection of discrete plumes from the different emitting regions and for determining the background concentration

  8. Methane emissions from dairy lagoons in the western United States.

    PubMed

    Leytem, A B; Bjorneberg, D L; Koehn, A C; Moraes, L E; Kebreab, E; Dungan, R S

    2017-08-01

    Methane generation from dairy liquid storage systems is a major source of agricultural greenhouse gas emissions. However, little on-farm research has been conducted to estimate and determine the factors that may affect these emissions. Six lagoons in south-central Idaho were monitored for 1 yr, with CH4 emissions estimated by inverse dispersion modeling. Lagoon characteristics thought to contribute to CH4 emissions were also monitored over this time period. Average emissions from the lagoons ranged from 30 to 126 kg/ha per day or 22 to 517 kg/d. Whereas we found a general trend for greater emissions during the summer, when temperatures were greater, events such as pumping, rainfall, freeze or thaw of lagoon surfaces, and wind significantly increased CH4 emissions irrespective of temperature. Lagoon physicochemical characteristics, such as total solids, chemical oxygen demand, and volatile solids, were highly correlated with emission. Methane prediction models were developed using volatile solids, wind speed, air temperature, and pH as independent variables. The US Environmental Protection Agency methodology for estimating CH4 emissions from manure storage was used for comparison of on-farm CH4 emissions from 1 of the lagoon systems. The US Environmental Protection Agency method underestimated CH4 emissions by 48%. An alternative methodology, using volatile solids degradation factor, provided a more accurate estimate of annual emissions from the lagoon system and may hold promise for applicability across a range of dairy lagoon systems in the United States. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

  9. Eutrophication increases methane emission to the atmosphere in tropical lagoons: insights from two Ivory Coast sites

    NASA Astrophysics Data System (ADS)

    José-mathieu Koné, Yéfanlan; Vieira Borges, Alberto

    2017-04-01

    Eutrophication increases methane emission to the atmosphere in tropical lagoons: insights from two Ivory Coast sites. Y J M Koné (1) & A.V. Borges (2) (1) Centre de recherches océanologiques (CRO) d'Abidjan, (Ivory Coast) (2) University of Liège, Chemical Oceanography Unit, Liège, Belgium (Belgium) Eutrophication is a worldwide environmental problem and a definitive solution is far from being achieved, despite the large number of studies documenting its causes. In small aquatic ecosystems, excessive growth of macrophytes is a well known undesirable consequence of eutrophication. When these plants die and sink to the bottom the decomposing biomass depletes oxygen content in the water column thus leading to anoxia promoting methane (CH4) production. Here, we reported the CH4 data obtained during six campaigns covering the annual cycle in two small lagoons of Ivory Coast (Ono, Kodjoboué) that are contrasted in the degree of eutrophication and the corresponding coverage of macrophytes (e.g. Echinochloa pyramidalis, Eichhornia crassipes, Hydrilla verticillata). Our data showed a high spatio-temporal variability of CH4 within the lagoons and between the two systems, with CH4 concentrations in surface waters ranging between 80 to 74,604 nmol L-1. The highest CH4 concentration values were observed in the eutrophic Ono lagoon that is covered by 80% of macrophytes, suggesting that lagoons dominated by macrophytes are significant sources of CH4 toward the atmosphere.

  10. Methane and ammonia emissions from New Mexico dairy lagoons in summer

    USDA-ARS?s Scientific Manuscript database

    Gaseous emissions of concern from commercial dairy operations include methane and ammonia. Dairy wastewater lagoons are sources of emission for both these gases. We quantified emissions of methane and ammonia from a lagoon system at a commercial open lot dairy in eastern New Mexico using open path l...

  11. Methane Cycling and Flux in Mangrove Ecosystems: A Comparison of Natural and Impacted Coastal Lagoons on the Yucatan Peninsula, Mexico

    NASA Astrophysics Data System (ADS)

    Young, M.; Paytan, A.; Miller, L.

    2001-12-01

    Tropical and subtropical wetlands are thought to be the dominant natural source of methane to the atmosphere, and mangrove ecosystems cover approximately 170,000 square kilometers of tropical and sub-tropical land, and dominating approximately 75 percent of the coastline between 25 degrees N and 25 degrees S. Previous studies have shown extremely wide ranges of methane flux from mangrove ecosystems, and have indicated that anthropogenic disturbances such as pollution, sewage discharge, and alteration of freshwater influx can have significant impacts on methane flux from mangrove ecosystems. Due to rapid population growth in tropical and sub-tropical areas and increasing impacts to coastal zones, it is important to obtain information regarding both natural and anthropogenic factors influencing methane cycling and flux within mangrove ecosystems, and to create a better estimate of the contribution of mangrove ecosystems to the global methane budget. Sampling for this study was conducted in three tropical coastal lagoons surrounded by mangrove vegetation located on the Yucatan Peninsula, Mexico. The three lagoons, Chelem, Celestun, and Terminos have similar vegetation and underlying geology, and are affected by similar seasonal patterns of temperature and precipitation. Significant differences in groundwater discharge and type and extent of anthropogenic impacts exist between the three lagoons. Chelem has moderate to low pollution and little to no ground water discharge. Celestun has very little pollution and large ground water discharges, while Terminos has relatively high impacts from pollution and human disturbance and varying ground water discharge. Previously reported data from these lagoons show distinct differences in methane concentrations in the sediment and water from Chelem in comparison to the concentrations measured in Celestun. Data collected over three seasons from Chelem and Celestun will be presented, providing information about seasonal variability

  12. Methane fluxes from tropical coastal lagoons surrounded bymangroves, Yucatán, Mexico

    USGS Publications Warehouse

    Chuang, Pei-Chuan; Young, Megan B.; Dale, Andrew W.; Miller, Laurence G.; Herrera-Silveira, Jorge A; Paytan, Adina

    2017-01-01

    Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m−2 d−1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

  13. Methane fluxes from tropical coastal lagoons surrounded by mangroves, Yucatán, Mexico

    NASA Astrophysics Data System (ADS)

    Chuang, P.-C.; Young, M. B.; Dale, A. W.; Miller, L. G.; Herrera-Silveira, J. A.; Paytan, A.

    2017-05-01

    Methane concentrations in the water column and emissions to the atmosphere were determined for three tropical coastal lagoons surrounded by mangrove forests on the Yucatán Peninsula, Mexico. Surface water dissolved methane was sampled at different seasons over a period of 2 years in areas representing a wide range of salinities and anthropogenic impacts. The highest surface water methane concentrations (up to 8378 nM) were measured in a polluted canal associated with Terminos Lagoon. In Chelem Lagoon, methane concentrations were typically lower, except in the polluted harbor area (1796 nM). In the relatively pristine Celestún Lagoon, surface water methane concentrations ranged from 41 to 2551 nM. Methane concentrations were negatively correlated with salinity in Celestún, while in Chelem and Terminos high methane concentrations were associated with areas of known pollution inputs, irrespective of salinity. The diffusive methane flux from surface lagoon water to the atmosphere ranged from 0.0023 to 15 mmol CH4 m-2 d-1. Flux chamber measurements revealed that direct methane release as ebullition was up to 3 orders of magnitude greater than measured diffusive flux. Coastal mangrove lagoons may therefore be an important natural source of methane to the atmosphere despite their relatively high salinity. Pollution inputs are likely to substantially enhance this flux. Additional statistically rigorous data collected globally are needed to better consider methane fluxes from mangrove-surrounded coastal areas in response to sea level changes and anthropogenic pollution in order to refine projections of future atmospheric methane budgets.

  14. Methane in Sediments From Three Tropical, Coastal Lagoons on the Yucatan Peninsula, Mexico

    NASA Astrophysics Data System (ADS)

    Young, B.; Paytan, A.; Miller, L.; Herrera-Silveira, J.

    2002-12-01

    Tropical wetlands are significant sources of methane (CH4) to the atmosphere, and the majority of research on methane flux and cycling in the tropics has been conducted in fresh-water wetlands and lakes. However, several previous studies have shown that tropical coastal ecosystems can produce significant methane flux to the atmosphere despite the presence of moderate to marine salinities. Information regarding methane cycling within the sediments is crucial to understanding how natural and anthropogenic changes may influence these systems. We measured methane concentrations in sediments from two tropical coastal lagoons during different seasons, as well as in a third, heavily polluted, lagoon (Terminos) during the rainy season. These three lagoons, Celestun, Chelem, and Terminos, have similar vegetation, seasonal temperature and rainfall patterns, and substrate geology, but very different levels of ground water discharge and pollution. Methane concentrations in Celestun and Terminos lagoon showed high spatial variability(> 0.001 to 5 mmol kg-1 wet sediment), while sediments in Chelem Lagoon, which has near marine salinities and little sewage discharge, showed much lower variability of methane concentrations. Methane concentrations in Celestun sediments displayed two predominant patterns: some profiles contained a peak in methane concentration (1 to 2 mmole methane kg-1 wet sediment) between 5 and 15 cm below the surface while the other sediment profiles instead displayed a steady or monotonic increase in methane concentration with depth to approximately 0.025-0.080 mmol kg-1 at 10-15cm below surface followed by stable methane concentrations to the bottom of the cores (20-45 cm below the surface). A subsurface peak in methane concentrations was also found in some locations in Chelem, however, the concentrations were much lower than those measured in Celestun. Previous studies have shown that sewage pollution may drastically increase methane production in tropical

  15. Quantifying Methane Fluxes in Sediments from Mangrove-dominated Costal Lagoons

    NASA Astrophysics Data System (ADS)

    Chuang, P.; Young, M. B.; Paytan, A.

    2012-12-01

    Many studies have focused on methane emission from wetland sediments to the water column and atmosphere. However, there is growing evidence that organic rich, highly productive coastal areas such as mangrove-dominated lagoons and estuaries may have high rates of atmospheric methane flux, particularly in polluted areas. Dissolved methane concentrations in surface water and sediments have been measured in two coastal mangrove ecosystems (Celestún and Chelem Lagoons) on the Yucatán Peninsula, Mexico and the estimated diffusive methane fluxes to the atmosphere in both lagoons can reach to 2600 and 80 kg CH4/yr respectively with a much larger yet not quantified ebullition flux . The objectives of this study are to understand the sources and sinks for methane in sediments, how much methane is released from the sediment to water column and the relative contribution of diffusive and bubble fluxes. In addition rates/percentages of methane oxidized in the sediment and water column that lower methane flux to the atmosphere are quantified. Sedimentary geochemical data (methane, sulfate, chloride, particulate organic carbon (POC) and stable carbon isotopes of headspace methane) from the two lagoons were also measured to determine the impact of different salinities and degrees of pollution on POC mineralization and methane fluxes. Stable carbon isotopes of methane data indicate gas productions mainly by CO2 reduction with minor acetate fermentation signatures. A numerical transport-reaction model will be apply to the data to estimate sulfate reduction, methane oxidation and production rates and advective methane fluxes. The modeled results will be compared to methane bubble fluxes measured by flux chambers to obtain total methane emissions from sediment and discuss the role of methane from mangriove areas in impacting global climate change.

  16. Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants.

    PubMed

    Pan, Yuting; Ye, Liu; van den Akker, Ben; Ganigué Pagès, Ramon; Musenze, Ronald S; Yuan, Zhiguo

    2016-02-02

    "Sludge-drying lagoons" are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge.

  17. [Research progress on methane oxidation in landfill cover soil].

    PubMed

    Wang, Yun-long; Hao, Yong-jun; Wu, Wei-xiang; Chen, Ying-xu

    2007-01-01

    Methane is the second largest contributor after carbon dioxide to global warming, while landfill is considered as one of the major sources of methane emission, accounting for 1.5%-15% of the global methane sources. Methanotrophic microorganisms play an important role in regulating global methane content, and landfill cover soil is proved to have high capacity of methane oxidation. The study of methanotrophic microorganisms in landfill cover soil and their mechanisms in methane oxidation becomes one of the hot research fields in environmental science and applied microbiology. This review summarized the recent progress on the research of methanotrophic microorganisms, mechanisms and dynamics of microbial methane oxidation, co-metabolism of methane and trace landfill gases, and environmental factors affecting methane oxidation in landfill cover soil. Some perspectives for further research on methanotrophic microorganisms in landfill cover soil were discussed.

  18. Methane and sulfate dynamics in sediments from mangrove-dominated tropical coastal lagoons, Yucatan, Mexico

    USGS Publications Warehouse

    Chuang, P. C.; Young, Megan B.; Dale, Andrew W.; Miller, Laurence G.; Herrera-Silveira, Jorge A.; Paytan, Adina

    2016-01-01

    Porewater profiles in sediment cores from mangrove-dominated coastal lagoons (Celestún and Chelem) on the Yucatán Peninsula, Mexico, reveal the widespread coexistence of dissolved methane and sulfate. This observation is interesting since dissolved methane in porewaters is typically oxidized anaerobically by sulfate. To explain the observations we used a numerical transport-reaction model that was constrained by the field observations. The model suggests that methane in the upper sediments is produced in the sulfate reduction zone at rates ranging between 0.012 and 31 mmol m−2 d−1, concurrent with sulfate reduction rates between 1.1 and 24 mmol SO42− m−2 d−1. These processes are supported by high organic matter content in the sediment and the use of non-competitive substrates by methanogenic microorganisms. Indeed sediment slurry incubation experiments show that non-competitive substrates such as trimethylamine (TMA) and methanol can be utilized for microbial methanogenesis at the study sites. The model also indicates that a significant fraction of methane is transported to the sulfate reduction zone from deeper zones within the sedimentary column by rising bubbles and gas dissolution. The shallow depths of methane production and the fast rising methane gas bubbles reduce the likelihood for oxidation, thereby allowing a large fraction of the methane formed in the sediments to escape to the overlying water column.

  19. Eddy Covariance Measurements of Methane Emissions from a Dairy Farm Waste Lagoon

    NASA Astrophysics Data System (ADS)

    Sokol, A. B.; Lauvaux, T.; Richardson, S.; Hlywiak, J.; Davis, K. J.; Hristov, A. N.

    2016-12-01

    Livestock manure management in dairy operations is a known source of methane (CH4), a potent greenhouse gas. Anaerobic waste lagoons are a common manure management technique; thus, their associated CH4 emissions are relevant to national greenhouse gas inventories and local air quality. Our objective was to characterize the variability of summertime CH4 emissions from a lagoon at a dairy facility in central Pennsylvania. Continuous flux measurements were taken over two weeks in July using the eddy covariance method, which uses high-frequency gas concentration and three-dimensional wind speed measurements to calculate turbulent fluxes from a source area. After data filtration based on turbulence characteristics and source area, the average CH4 flux density from the lagoon was estimated to be 99 μmol m-2 s-1. This implies daily lagoon emissions of 881 kg CH4, corresponding to an average emission rate of 340 g CH4 per cow per day. We observed no apparent relationship between emissions and air temperature or relative humidity, though an extended measurement period is needed to better quantify the relationship that is expected to exist between air and/or slurry temperature and CH4 flux. Our measured per-area emission rate is toward the high end of the range of estimates found in the literature. These results contribute to greenhouse gas inventory development and could have important implications for emission mitigation strategies.

  20. Can Biochar Covers Reduce Emissions from Manure Lagoons While Capturing Nutrients?

    EPA Science Inventory

    The unique physical and chemical properties of biochars make them promising materials for odor, gas, and nutrient sorption. Floating covers made from organic materials (biocovers) are one option for reducing odor and gas emissions from livestock manure lagoons. This study evaluat...

  1. Effects of landfill cover design on methane recovery systems

    SciTech Connect

    Massmann, J.W.; Moore, C.A.

    1983-12-01

    A finite difference computer program to aid in optimizing landfill cover design was developed by the authors. The program was used to compare the methane yield from sand-covered and clay-covered landfills equipped with methane recovery systems. The results of this comparison and a brief description of the finite difference program are presented in this paper. These results indicate that a clay cover can restrict air inflow into the landfill system, thus preventing oxygen poisoning of the methane-producing organisms. The practice of monitoring methane to air ratios in the pipelines of the recovery system in order to forewarn of oxygen infiltration into the fill material was shown to be ineffective in some situations. More reliable methods to forewarn of oxygen poisoning were suggested.

  2. Methane and sulfate dynamics in sediments from mangrove-dominated tropical coastal lagoons, Yucatán, Mexico

    NASA Astrophysics Data System (ADS)

    Chuang, P.-C.; Young, M. B.; Miller, L. G.; Herrera-Silveira, J. A.; Paytan, A.

    2015-11-01

    Methane, sulfate and chloride concentrations in sediment porewater from two coastal mangrove ecosystems (Celestún and Chelem Lagoons) on the Yucatán Peninsula, Mexico were measured. In these sediments methane exists in shallow sediments where sulfate is not depleted, and sulfate reduction is actively occurring. A transport-reaction model depicting the various production and consumption processes for methane and sulfate is used to elucidate processes responsible for this observation. The model illustrates that methane in the upper sediments is produced in-situ supported by high dissolved organic matter as well as by non-competitive substrates. In addition methane is contributed to porewater in the upper sediments, where sulfate reduction occurs, by transport from deeper zones within the sedimentary column through bubbles dissolution and diffusion. The shallow methane production and accumulation depths in these sediments promote high methane fluxes to the water column and atmosphere.

  3. Methane oxidation in simulated landfill cover soil environments

    SciTech Connect

    Visscher, A. de; Thomas, D.; Boeckx, P.; Cleemput, O. van

    1999-06-01

    Methane is an important greenhouse gas. Its contribution to the enhanced global warming is estimated at 12%. A considerable fraction of the methane that is produced by landfills is oxidized by its covering soil before it can reach the atmosphere. This process was studied in soil columns that simulate landfill cover soil environments. The methane uptake was followed as a function of time. In soils of agricultural origin, a maximum value of 10.7 mol m{sup {minus}2}{sub column} d{sup {minus}1} was observed. Mixing sugar beet leaves with the soil led to a temporary stimulation of the methane oxidation rate, whereas a wheat straw amendment led to permanent stimulation. Soil originating from a real landfill cover oxidized on the order of 15 mol m{sup {minus}2}{sub column} d{sup {minus}1}, the highest value found in the literature to date. The soil gas composition was studied as a function of depth. With a new batch incubation technique, methane oxidation kinetics were determined in samples taken from the soil column. By combining this kinetic data with the soil gas composition data, the actively methane oxidizing zone in the soil column could be determined and an in situ assessment of oxygen limitation could be performed. Methane oxidation takes place mainly in the top 30 cm of the covering soil.

  4. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  5. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  6. Effectiveness of porous covers for control of ammonia, reduced sulfur compounds, total hydrocarbons, selected volatile organic compounds, and odor from hog manure storage lagoons.

    PubMed

    Regmi, Shekhar; Ongwandee, Maneerat; Morrison, Glenn; Fitch, Mark; Surampalli, Rao

    2007-06-01

    Anaerobic lagoons are a major source of odor at concentrated animal feeding operations. Seven different kinds of artificial (geotextile and polyethylene foam) and natural (straw and redwood) permeable lagoon covers were evaluated for their potential to reduce odorous emissions generated by anaerobic waste lagoons. A novel floating sampling raft was constructed and used to simultaneously evaluate the effectiveness of lagoon covers on an operating swine waste lagoon. The air collected from the raft was evaluated for odor, total reduced sulfur (TRS) compounds, ammonia, total hydrocarbons, dimethyldisulfide, and trimethylamine. The emission rates from the lagoon were highly variable both temporally and spatially. All of the lagoon covers substantially reduced TRS emissions and odor. Geotextile fabric and a recycled foam cover exhibited the greatest reduction in total hydrocarbon emissions; natural covers were less effective. Because of consistently low emission rates of ammonia, no statistically significant reduction of ammonia emissions were observed from any of the lagoon covers.

  7. Limits and dynamics of methane oxidation in landfill cover soils

    USDA-ARS?s Scientific Manuscript database

    In order to understand the limits and dynamics of methane (CH4) oxidation in landfill cover soils, we investigated CH4 oxidation in daily, intermediate, and final cover soils from two California landfills as a function of temperature, soil moisture and CO2 concentration. The results indicate a signi...

  8. Effect of landfill cover layer modification on methane oxidation.

    PubMed

    Hu, Lifang; Long, Yuyang

    2016-12-01

    Levels of methane (CH4) oxidation in materials used for landfill cover attained in the laboratory are not often replicated in the field due to effects from the surrounding environment. This study investigates the three dominant factors affecting CH4 oxidation in the cover layer, namely, the thickness of cover layer, the methanotroph spraying manner, and the osmotic coefficient of the cover material. Results show that improved CH4 emission performance of the cover layer can be realized if methanotroph are introduced, meaning that a thinner cover layer is required. The highest CH4 emission reduction can be realized by spraying methanotroph into the top, middle, and bottom layers of a 30-cm thick cover layer with an osmotic coefficient of 7.76 × 10(-5) cm s(-1). Comparing results on cover layer thickness, methane monooxygenase (MMO) activity was much lower with increasing thickness meaning that the thicker cover could reduce O2 availability, thus inhibiting MMO activity. This suggests that MMO may be responsible for differences in CH4 emission reduction and/or oxidation making the osmotic coefficient an important factor for cover layer material.

  9. Exopolysaccharide control of methane oxidation in landfill cover soil

    SciTech Connect

    Hilger, H.A.; Liehr, S.K.; Barlaz, M.A.

    1999-12-01

    The study objective was to examine whether a relationship exists between the accumulation of exopolymeric substances (EPS) in landfill cover soil and the gradual decline in biotic methane oxidation observed in laboratory soil columns sparged with synthetic landfill gas. A mathematical model that combined multicomponent gas diffusion along the vertical axis of the columns with biotic methane oxidation was used to predict vertical gas gradients in the columns. An initial trial assumed methane oxidizers were embedded in a thin base layer of biofilm coating the soil, and the model predictions fit experimental data from soil columns early in their operating period. A second trial modeled the same system with a thick EPS layer coating the base biofilm and limiting diffusion of gases into and out of the cells. Predictions from the alter trials fit experimental data from soil columns later in their operating period when lower methane consumption rates were observed. The model results suggest that EPS accumulation may regulate methane oxidation rates in landfill covers.

  10. Spatial and temporal land cover changes in Terminos Lagoon Reserve, Mexico.

    PubMed

    Soto-Galera, Ernesto; Piera, Jaume; López, Pilar

    2010-06-01

    Terminos Lagoon ecosystem is the largest fluvial-lagoon estuarine system in the country and one of the most important reserves of coastal flora and fauna in Mexico. Since the seventies, part of the main infrastructure for country's oil extraction is located in this area. Its high biodiversity has motivated different type of studies including deforestation processes and land use planning. In this work we used satellite image analysis to determine land cover changes in the area from 1974 to 2001. Our results indicate that tropical forest and mangroves presented the most extensive losses in its coverage. In contrast, urban areas and induced grassland increased considerably. In 2001 more than half of the ecosystem area showed changes from its original land cover, and a third part of it was deteriorated. The main causes of deforestation were both the increase in grassland and the growth of urban areas. However, deforestation was attenuated by natural reforestation and plant canopy recovery. We conclude that the introduction of cattle and urban development were the main causes for the land cover changes; however, the oil industry activity located in the ecosystem, has promoted indirectly to urban growth and rancher boom.

  11. Estimating Emissions of Ammonia and Methane from an Anaerobic Livestock Lagoon Using Micrometeorological Methods and Inverse Modeling

    NASA Astrophysics Data System (ADS)

    Shonkwiler, K. B.; Ham, J. M.; Williams, C.

    2012-12-01

    Evaluating the impact of increased carbon and nitrogen emissions on local air quality and regional bionetworks due to animal agricultural activity is of great interest to the public, political, economic and ecological welfare of areas within the scope of these practices. Globally, livestock operations account for 64% of annual anthropogenic emissions of ammonia (NH3) [1]. Concerning methane (CH4), anaerobic lagoons from commercial dairy operations contribute the second largest share of CH4 emissions from manure in the United States[1], and additionally are a local source of NH3 as well. Anaerobic lagoons are commonly used in commercial animal agriculture and as significant local sources of greenhouse gases (GHG), there is a strong need to quantify GHG emissions from these systems. In 2012 at a commercial dairy operation in Northern Colorado, USA, measurements of CH4 were made using eddy covariance (EC), while NH3 was estimated using a combination of real-time monitoring (cavity ring-down spectroscopy as well as time-integrated passive samplers). Methane emissions have been measured at this lagoon using EC since 2011, with fluxes ranging from 0.5 mg m-2 s-1 in early summer to >2 mg m-2 s-1 in late summer and early fall. Concentration data of both CH4 and NH3 were used to estimate emissions using a 2-dimensional inverse model based on solving the advection-diffusion equation[2]. In the case of the CH4-EC data, results from the inverse model were compared with the EC-derived flux estimates for enhanced parameterization of surface geometry within the lagoon environment. The model was then applied using measured NH3 concentrations to achieve emissions estimates. While NH3 fluxes from the lagoon tend to be much lower than those of CH4 by comparison, modeling emissions of NH3 from the simple geometry of a lagoon will assist in applying the model to more complex surfaces. [1] FAO, 2006. Livestock's long shadow: Environmental issues and options. Livestock, Environment, and

  12. Methane and sulfate dynamics in sediments from mangrove-dominated tropical coastal lagoons, Yucatán, Mexico

    NASA Astrophysics Data System (ADS)

    Chuang, Pei-Chuan; Young, Megan B.; Dale, Andrew W.; Miller, Laurence G.; Herrera-Silveira, Jorge A.; Paytan, Adina

    2016-05-01

    Porewater profiles in sediment cores from mangrove-dominated coastal lagoons (Celestún and Chelem) on the Yucatán Peninsula, Mexico, reveal the widespread coexistence of dissolved methane and sulfate. This observation is interesting since dissolved methane in porewaters is typically oxidized anaerobically by sulfate. To explain the observations we used a numerical transport-reaction model that was constrained by the field observations. The model suggests that methane in the upper sediments is produced in the sulfate reduction zone at rates ranging between 0.012 and 31 mmol m-2 d-1, concurrent with sulfate reduction rates between 1.1 and 24 mmol SO42- m-2 d-1. These processes are supported by high organic matter content in the sediment and the use of non-competitive substrates by methanogenic microorganisms. Indeed sediment slurry incubation experiments show that non-competitive substrates such as trimethylamine (TMA) and methanol can be utilized for microbial methanogenesis at the study sites. The model also indicates that a significant fraction of methane is transported to the sulfate reduction zone from deeper zones within the sedimentary column by rising bubbles and gas dissolution. The shallow depths of methane production and the fast rising methane gas bubbles reduce the likelihood for oxidation, thereby allowing a large fraction of the methane formed in the sediments to escape to the overlying water column.

  13. Comparison of Methods to Assess the Fate of Methane in a Landfill-Cover Soil

    NASA Astrophysics Data System (ADS)

    Gomez, K. E.; Schroth, M. H.; Eugster, W.; Niklaus, P.; Oester, P.; Zeyer, J.

    2008-12-01

    A substantial fraction of the greenhouse gas methane released into the atmosphere is produced in terrestrial environments such as wetlands, rice paddy fields, and landfills. However, the amount of methane that is emitted from these environments is often reduced by microbial methane oxidation, mediated by methanotrophic microorganisms. Methanotrophs are ubiquitous in soils and represent the largest biological sink for methane. We performed a series of field experiments in summer 2008 to compare several state-of- the-art methods to assess the fate of methane in a landfill-cover soil near Liestal (BL), Switzerland. Methods employed included eddy-covariance and field-chamber measurements to quantify net methane flux at the landfill surface. In addition, methane concentrations at the landfill surface were monitored using a portable methane detector. Methane fluxes within the cover soil were estimated from methane-concentration profiles in conjunction with radon measurements. Additionally, gas push-pull tests were employed for in-situ quantification of methane oxidation in the cover soil. Finally, methane stable-carbon-isotope measurements were conducted to corroborate methane oxidation in the cover soil. Preliminary results indicate that each method provides unique information, and when combined, the data provide detailed insight in the fate of methane in the cover soil. The investigated landfill-cover soil appears to be ordinarily a net sink for methane. However, it can quickly turn into a net source of methane under adverse meteorological conditions.

  14. Seasonal variability of carbon dioxide and methane in the rivers and lagoons of Ivory Coast (West Africa)

    NASA Astrophysics Data System (ADS)

    Koné, Y. J. M.; Abril, G.; Delille, B.; Borges, A. V.

    2009-04-01

    We report a data-set of carbon dioxide (CO2) and dissolved methane (CH4) in three rivers (Bia, Tanoé and Comoé) and five lagoons (Tendo, Aby, Ebrié, Potou and Grand-Lahou) of Ivory Coast (West Africa), during the four main climatic seasons (high dry season, high rainy season, low dry season and low rainy season). The surface waters of the three rivers were oversaturated in CO2 and CH4 with respect to atmospheric equilibrium, the seasonal variability of CO2 and CH4 seemed to be largely controlled by dilution during the flooding period. The strong correlation of CH4 concentrations with the partial pressure of CO2 (pCO2) confirm the dominance of a continental sources (from soils) for both CO2 and CH4 in these rivers. The largest CH4 over-saturations and diffusive air-water CH4 fluxes were observed in the Tendo and Aby lagoons that are permanently stratified systems (unlike the other 3 lagoons), leading to anoxic bottom waters favorable for a large CH4 production. In addition, these two stratified lagoons showed low pCO2 values due to high primary production, which suggests an efficient transfer of organic matter across the pycnocline. As a result, the stratified Tendo and Aby lagoons were respectively, a low source of CO2 to the atmosphere and a sink of atmospheric CO2 while the other 3 well-mixed lagoons were strong sources of CO2 to the atmosphere but lower sources of CH4 to the atmosphere.

  15. Biotic landfill cover treatments for mitigating methane emissions.

    PubMed

    Hilgeri, Helene; Humer, Marion

    2003-05-01

    Landfill methane (CH4) emissions have been cited as one of the anthropogenic gas releases that can and should be controlled to reduce global climate change. This article reviews recent research that identifies ways to enhance microbial consumption of the gas in the aerobic portion of a landfill cover. Use of these methods can augment CH4 emission reductions achieved by gas collection or provide a sole means to consume CH4 at small landfills that do not have active gas collection systems. Field studies indicate that high levels of CH4 removal can be achieved by optimizing natural soil microbial processes. Further, during biotic conversion, not all of the CH4 carbon is converted to carbon dioxide (CO2) gas and released to the atmosphere; some of it will be sequestered in microbial biomass. Because biotic covers can employ residuals from other municipal processes, financial benefits can also accrue from avoided costs for residuals disposal.

  16. Can Biochar Covers Reduce Emissions from Manure Lagoons While Capturing Nutrients?

    PubMed

    Dougherty, Brian; Gray, Myles; Johnson, Mark G; Kleber, Markus

    2017-05-01

    The unique physical and chemical properties of biochars make them promising materials for odor, gas, and nutrient sorption. Floating covers made from organic materials (biocovers) are one option for reducing odor and gas emissions from livestock manure lagoons. This study evaluated the potential of floating biochar covers to reduce odor and gas emissions while simultaneously sorbing nutrients from liquid dairy manure. This new approach has the potential to mitigate multiple environmental problems. Two biochars were tested: one made via gasification of Douglas fir chips at 650°C (FC650), and the other made from a mixture of Douglas fir [ (Mirb.) Franco] bark and center wood pyrolyzed at 600°C (HF600). The HF600 biocover reduced mean headspace ammonia concentration by 72 to 80%. No significant reduction was found with the FC650 biocover. Nutrient uptake ranged from 0.21 to 4.88 mg N g biochar and 0.64 to 2.70 mg P g biochar for the HF600 and FC650 biochars, respectively. Potassium ranged from a loss of 4.52 to a gain of 2.65 mg g biochar for the FC650 and HF600 biochars, respectively. The biochars also sorbed Ca, Mg, Na, Fe, Al, and Si. In a separate sensory evaluation, judges assessed odor offensiveness and odor threshold of five biocover treatments including four biochars applied over dairy manure. Reductions in mean odor offensiveness and mean odor threshold were observed in three treatments compared with the control. These results show that biochar covers hold promise as an effective practice for reducing odor and gas emissions while sorbing nutrients from liquid dairy manure. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. Methane oxidation in a landfill cover with capillary barrier.

    PubMed

    Berger, J; Fornés, L V; Ott, C; Jager, J; Wawra, B; Zanke, U

    2005-01-01

    The methane oxidation potential of a landfill cover with capillary barrier was investigated in an experimental plant (4.8 m x 0.8 m x 2.1m). The cover soil consisted of two layers, a mixture of compost plus sand (0.3 m) over a layer of loamy sand (0.9 m). Four different climatic conditions (summer, winter, spring and fall) were simulated. In and outgoing fluxes were measured. Gas composition, temperature, humidity, matrix potential and gas pressure were monitored in two profiles. CH4 oxidation rate within the investigated top cover ranged from 98% to 57%. The minimum was observed for a short time after irrigation. Temperature distribution, gas concentration profiles and lab-scaled batch experiments indicate that before irrigation the highest oxidising activity took place in a depth of about 30 cm. After irrigation the oxidising horizon seemed to migrate upwards since methanotrophic bacteria develop better there due to an adequate supply with oxygen. It can be assumed that the absence of oxygen is one of the most important limiting factors for the CH4 oxidation process. Abrupt cross-overs between horizons of different soil material may lead to zones of increased water saturation and decreased soil respiration.

  18. Nitrous oxide and methane emissions from cryptogamic covers.

    PubMed

    Lenhart, Katharina; Weber, Bettina; Elbert, Wolfgang; Steinkamp, Jörg; Clough, Tim; Crutzen, Paul; Pöschl, Ulrich; Keppler, Frank

    2015-10-01

    Cryptogamic covers, which comprise some of the oldest forms of terrestrial life on Earth (Lenton & Huntingford, ), have recently been found to fix large amounts of nitrogen and carbon dioxide from the atmosphere (Elbert et al., ). Here we show that they are also greenhouse gas sources with large nitrous oxide (N2 O) and small methane (CH4 ) emissions. Whilst N2 O emission rates varied with temperature, humidity, and N deposition, an almost constant ratio with respect to respiratory CO2 emissions was observed for numerous lichens and bryophytes. We employed this ratio together with respiration data to calculate global and regional N2 O emissions. If our laboratory measurements are typical for lichens and bryophytes living on ground and plant surfaces and scaled on a global basis, we estimate a N2 O source strength of 0.32-0.59 Tg year(-1) for the global N2 O emissions from cryptogamic covers. Thus, our emission estimate might account for 4-9% of the global N2 O budget from natural terrestrial sources. In a wide range of arid and forested regions, cryptogamic covers appear to be the dominant source of N2 O. We suggest that greenhouse gas emissions associated with this source might increase in the course of global change due to higher temperatures and enhanced nitrogen deposition.

  19. Testing a biofilter cover design to mitigate dairy effluent pond methane emissions.

    PubMed

    Pratt, Chris; Deslippe, Julie; Tate, Kevin R

    2013-01-02

    Biofiltration, whereby CH(4) is oxidized by methanotrophic bacteria, is a potentially effective strategy for mitigating CH(4) emissions from anaerobic dairy effluent lagoons/ponds, which typically produce insufficient biogas for energy recovery. This study reports on the effectiveness of a biofilter cover design at oxidizing CH(4) produced by dairy effluent ponds. Three substrates, a volcanic pumice soil, a garden-waste compost, and a mixture of the two, were tested as media for the biofilters. All substrates were suspended as 5 cm covers overlying simulated dairy effluent ponds. Methane fluxes supplied to the filters were commensurate with emission rates from typical dairy effluent ponds. All substrates oxidized more than 95% of the CH(4) influx (13.9 g CH(4) m(-3) h(-1)) after two months and continued to display high oxidation rates for the remaining one month of the trial. The volcanic soil biofilters exhibited the highest oxidation rates (99% removal). When the influx CH(4) dose was doubled for a month, CH(4) removal rates remained >90% for all substrates (maximum = 98%, for the volcanic soil), suggesting that biofilters have a high capacity to respond to increases in CH(4) loads. Nitrous oxide emissions from the biofilters were negligible (maximum = 19.9 mg N(2)O m(-3) h(-1)) compared with CH(4) oxidation rates, particularly from the volcanic soil that had a much lower microbial-N (75 mg kg(-1)) content than the compost-based filters (>240 mg kg(-1)). The high and sustained CH(4) oxidation rates observed in this laboratory study indicate that a biofilter cover design is a potentially efficient method to mitigate CH(4) emissions from dairy effluent ponds. The design should now be tested under field conditions.

  20. Constraints on methane oxidation in ice-covered boreal lakes

    NASA Astrophysics Data System (ADS)

    Denfeld, Blaize A.; Ricão Canelhas, Monica; Weyhenmeyer, Gesa A.; Bertilsson, Stefan; Eiler, Alexander; Bastviken, David

    2016-07-01

    Boreal lakes can be ice covered for a substantial portion of the year at which time methane (CH4) can accumulate below ice. The amount of CH4 emitted at ice melt is partially determined by the interplay between CH4 production and CH4 oxidation, performed by methane-oxidizing bacteria (MOB). Yet the balance between oxidation and emission and the potential for CH4 oxidation in various lakes during winter is largely unknown. To address this, we performed incubations at 2°C to screen for wintertime CH4 oxidation potential in seven lakes. Results showed that CH4 oxidation was restricted to three lakes, where the phosphate concentrations were highest. Molecular analyses revealed that MOB were initially detected in all lakes, although an increase in type I MOB only occurred in the three lake water incubations where oxidation could be observed. Accordingly, the increase in CO2 was on average 5 times higher in these three lake water incubations. For one lake where no oxidation was measured, we tested if temperature and CH4 availability could trigger CH4 oxidation. However, regardless of incubation temperatures and CH4 concentrations, ranging from 2 to 20°C and 1-500 μM, respectively, no oxidation was observed. Our study indicates that some lakes with active wintertime CH4 oxidation may have low emissions during ice melt, while other and particularly nutrient poor lakes may accumulate large amounts of CH4 below ice that, in the absence of CH4 oxidation, will be emitted following ice melt. This variability in CH4 oxidation rates between lakes needs to be accounted for in large-scale CH4 emission estimates.

  1. [Depth Profiles of Methane Oxidation Kinetics and the Related Methanotrophic Community in a Simulated Landfill Cover].

    PubMed

    Xing, Zhi-lin; Zhao, Tian-tao; Gao, Yan-hui; He, Zhi; Yang, Xu; Peng, Xu-ya

    2015-11-01

    Simulated landfill cover with real time online monitoring system was developed using cover soils. Then the system started and the concentrations of bio-gas in various depths were continuously monitored, and it was found that the system ran continually and stably after 2-3 h when methane flux changed. After that, the relationship between regularity of methane oxidation and methane flux in landfill cover was analyzed. The results indicated that concentration of oxygen decreased with increasing methane flux when the depth was deeper than 20 cm, and no obvious correlation between oxygen concentration in landfill cover surface and methane flux, however, methane oxidation rate showed positive correlation with methane flux in various depths (range of R2 was 0.851-0.999). Kinetics of CH4 oxidation in landfill cover was fitted by CH4 -O2 dual-substrate model (range of R2 was 0.902-0.955), the half-saturation constant K(m) increasing with depth was 0.157-0.729 in dynamic condition. Finally, methanotrophs community structure in original cover soil sample and that in simulated landfill cover were investigated by high-throughout sequencing technology, and the statistics indicated that the abundance and species of methanotrophs in simulated landfill cover significantly increased compared with those in original cover soil sample, and type I methanotrophs including Methylobacter and Methylophilaceae and type II methanotrophs Methylocystis were dominant species.

  2. Limits and dynamics of methane oxidation in landfill cover soils.

    PubMed

    Spokas, Kurt A; Bogner, Jean E

    2011-05-01

    In order to understand the limits and dynamics of methane (CH(4)) oxidation in landfill cover soils, we investigated CH(4) oxidation in daily, intermediate, and final cover soils from two California landfills as a function of temperature, soil moisture and CO(2) concentration. The results indicate a significant difference between the observed soil CH(4) oxidation at field sampled conditions compared to optimum conditions achieved through pre-incubation (60 days) in the presence of CH(4) (50 ml l(-1)) and soil moisture optimization. This pre-incubation period normalized CH(4) oxidation rates to within the same order of magnitude (112-644 μg CH(4) g(-1) day(-1)) for all the cover soils samples examined, as opposed to the four orders of magnitude variation in the soil CH(4) oxidation rates without this pre-incubation (0.9-277 μg CH(4) g(-1) day(-1)). Using pre-incubated soils, a minimum soil moisture potential threshold for CH(4) oxidation activity was estimated at 1500 kPa, which is the soil wilting point. From the laboratory incubations, 50% of the oxidation capacity was inhibited at soil moisture potential drier than 700 kPa and optimum oxidation activity was typical observed at 50 kPa, which is just slightly drier than field capacity (33 kPa). At the extreme temperatures for CH(4) oxidation activity, this minimum moisture potential threshold decreased (300 kPa for temperatures <5°C and 50 kPa for temperatures >40°C), indicating the requirement for more easily available soil water. However, oxidation rates at these extreme temperatures were less than 10% of the rate observed at more optimum temperatures (∼ 30°C). For temperatures from 5 to 40°C, the rate of CH(4) oxidation was not limited by moisture potentials between 0 (saturated) and 50 kPa. The use of soil moisture potential normalizes soil variability (e.g. soil texture and organic matter content) with respect to the effect of soil moisture on methanotroph activity. The results of this study indicate

  3. Transport of marine fish larvae to Saroma-ko Lagoon (Hokkaido, Japan) in relation to the availability of zooplankton prey under the winter ice cover

    NASA Astrophysics Data System (ADS)

    Fortier, Martin; Fortier, Louis

    1997-02-01

    To assess the importance of ice-covered Saroma-ko Lagoon as a winter nursery area for young fish spawned offshore, we monitored the recruitment of marine fish larvae from the Sea of Okhotsk to the lagoon as well as the availability of larval fish prey under the ice cover from 24 February to 23 March 1992. Sand lance ( Ammodytes sp.) and walleye pollock ( Theragra chalcogramma) larvae recruited to the lagoon on flood tide whereas snake prickleback ( Lumpenus sagitta) larvae were exported to the Sea of Okhotsk on ebb. Before the ice breakup, ice microalgae made up the bulk of the microalgal biomass in the lagoon. The production and release of ice algae did not trigger the maturation of the late copepodite stages of copepods, and the proportion of adult females in the copepod assemblage remained low. The production of copepod nauplii (the main prey of fish larvae) under the ice was probably insufficient to insure suitable feeding and growth of fish larvae entering the lagoon in winter. Sand lance larvae, the most abundant species to colonize the lagoon in February-March, had to survive for nearly two months at low food abundance. Based on our results, the importance of Saroma-ko Lagoon as a winter nursery area for fish larvae appears negligible.

  4. Bio-tarp alternative daily cover prototypes for methane oxidation atop open landfill cells.

    PubMed

    Adams, Bryn L; Besnard, Fabien; Bogner, Jean; Hilger, Helene

    2011-05-01

    Final landfill covers are highly engineered to prevent methane release into the atmosphere. However, methane production begins soon after waste placement and is an unaddressed source of emissions. The methane oxidation capacity of methanotrophs embedded in a "bio-tarp" was investigated as a means to mitigate methane release from open landfill cells. The bio-tarp would also serve as an alternative daily cover during routine landfill operation. Evaluations of nine synthetic geotextiles identified two that would likely be suitable bio-tarp components. Pilot tarp prototypes were tested in continuous flow systems simulating landfill gas conditions. Multilayered bio-tarp prototypes consisting of alternating layers of the two geotextiles were found to remove 16% of the methane flowing through the bio-tarp. The addition of landfill cover soil, compost, or shale amendments to the bio-tarp increased the methane removal up to 32%. With evidence of methane removal in a laboratory bioreactor, prototypes were evaluated at a local landfill using flux chambers installed atop intermediate cover at a landfill. The multilayered bio-tarp and amended bio-tarp configurations were all found to decrease landfill methane flux; however, the performance efficacy of bio-tarps was not significantly different from controls without methanotrophs. Because highly variable methane fluxes at the field site likely confounded the test results, repeat field testing is recommended under more controlled flux conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials.

    PubMed

    Rachor, Ingke; Gebert, Julia; Gröngröft, Alexander; Pfeiffer, Eva-Maria

    2011-05-01

    The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm(-3), reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100g CH(4)m(-2)d(-1), covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH(4)m(-2)d(-1) and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of

  6. Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials

    SciTech Connect

    Rachor, Ingke; Gebert, Julia; Groengroeft, Alexander; Pfeiffer, Eva-Maria

    2011-05-15

    The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm{sup -3}, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH{sub 4} m{sup -2} d{sup -1}, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH{sub 4} m{sup -2} d{sup -1} and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity

  7. Rapid Methane Oxidation in a Landfill Cover Soil †

    PubMed Central

    Whalen, S. C.; Reeburgh, W. S.; Sandbeck, K. A.

    1990-01-01

    Methane oxidation rates observed in a topsoil covering a retired landfill are the highest reported (45 g m−2 day−1) for any environment. This microbial community had the capacity to rapidly oxidize CH4 at concentrations ranging from <1 ppm (microliters per liter) (first-order rate constant [k] = −0.54 h−1) to >104 ppm (k = −2.37 h−1). The physiological characteristics of a methanotroph isolated from the soil (characteristics determined in aqueous medium) and the natural population, however, were similar to those of other natural populations and cultures: the Q10 and optimum temperature were 1.9 and 31°C, respectively, the apparent half-saturation constant was 2.5 to 9.3 μM, and 19 to 69% of oxidized CH4 was assimilated into biomass. The CH4 oxidation rate of this soil under waterlogged (41% [wt/vol] H2O) conditions, 6.1 mg liter−1 day−1, was near rates reported for lake sediment and much lower than the rate of 116 mg liter−1 day−1 in the same soil under moist (11% H2O) conditions. Since there are no large physiological differences between this microbial community and other CH4 oxidizers, we attribute the high CH4 oxidation rate in moist soil to enhanced CH4 transport to the microorganisms; gas-phase molecular diffusion is 104-fold faster than aqueous diffusion. These high CH4 oxidation rates in moist soil have implications that are important in global climate change. Soil CH4 oxidation could become a negative feedback to atmospheric CH4 increases (and warming) in areas that are presently waterlogged but are projected to undergo a reduction in summer soil moisture. PMID:16348346

  8. Rapid methane oxidation in a landfill cover soil

    SciTech Connect

    Whalen, S.C.; Reeburgh, W.S.; Sandbeck, K.A. )

    1990-11-01

    Methane oxidation rates observed in a topsoil covering a retired landfill are the highest reported (45 g m{sup {minus}2} day{sup {minus}1}) for any environment. This microbial community had the capacity to rapidly oxidize CH{sub 4} at concentrations ranging from <1 ppm (microfilters per liter) (first-order rate constant (k) = {minus}0.54 h{sup {minus}1}) to >10{sup 4} ppm (k = {minus}2.37 h{sup {minus}1}). The physiological characteristics of a methanotroph isolated from the soil (characteristics determined in aqueous medium) and the natural population, however, were similar to those of other natural populations and cultures: the Q{sub 10} and optimum temperature were 1.9 and 31{degree}C, respectively, the apparent half-saturation constant was 2.5 to 9.3 {mu}M, and 19 to 69% of oxidized CH{sub 4} was assimilated into biomass. The CH{sub 4} oxidation rate of this soil was waterlogged (41% (wt/vol) H{sub 2}O) conditions, 6.1 mg liter{sup {minus}1} day{sup {minus}1}, was near rates reported for lake sediment and much lower than the rate of 116 mg liter{sup {minus}1} day{sup {minus}1} in the same soil under moist (11% H{sub 2}O) conditions. Since there are no large physiological differences between this microbial community and other CH{sub 4} oxidizers, we attribute the high CH{sub 4} oxidation rate in moist soil to enhanced CH{sub 4} transport to the microorganisms; gas-phase molecular diffusion is 10{sup 4}-fold faster than aqueous diffusion. These high CH{sub 4} oxidation rates in moist soil have implications that are important in global climate change. Soil CH{sub 4} oxidation could become a negative feedback to atmospheric CH{sub 4} increases (and warming) in areas that are presently waterlogged but are projected to undergo a reduction in summer soil moisture.

  9. Methane emissions from Southern High Plains dairy wastewater lagoons in the summer

    USDA-ARS?s Scientific Manuscript database

    Methane is a greenhouse gas with a global warming potential 25 fold that of CO2, and animal agriculture is recognized as a source of CH4to the atmosphere. Dairy farms on the Southern High Plains of New Mexico and Texas (USA) are typically open lot, and sources of CH4 are enteric emissions from cattl...

  10. Fluxes of carbon dioxide, methane and nitrous oxide in two contrastive fringing zones of coastal lagoon, Lake Nakaumi, Japan.

    PubMed

    Hirota, Mitsuru; Senga, Yukiko; Seike, Yasushi; Nohara, Seiichi; Kunii, Hidenobu

    2007-06-01

    We measured fluxes of carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) simultaneously in two typical fringing zones, sandy shore and salt marsh, of coastal lagoon, Lake Nakaumi, Japan, in mid-summer 2003. Our aim was to quantify net the greenhouse gases (GHGs) fluxes and examine key factors, which control variation of the GHGs fluxes in the two sites. Net CO(2) and CH(4) fluxes were markedly different between the two sites; magnitudes and variations of the both fluxes in sandy shore were lower than those of salt marsh. Meanwhile, magnitude and variation of net N(2)O flux in the two sites were similar. In sandy shore, temporal and spatial variation of the three GHGs fluxes were highly controlled by water level fluctuation derived from astronomic tide. In salt marsh, spatial variation of the three GHGs fluxes were correlated with aboveground biomass, and temporal variation of CO(2) and CH(4) fluxes were correlated with soil temperature. The sum of global warming potential, which was roughly estimated using the observed GHGs fluxes, was ca. 174-fold higher in salt marsh than in sandy shore.

  11. Spatial variability of soil gas concentration and methane oxidation capacity in landfill covers.

    PubMed

    Röwer, Inga Ute; Geck, Christoph; Gebert, Julia; Pfeiffer, Eva-Maria

    2011-05-01

    In order to devise design criteria for biocovers intended to enhance the microbial oxidation of landfill methane it is critical to understand the factors influencing gas migration and methane oxidation in landfill cover soils. On an old municipal solid waste landfill in north-western Germany soil gas concentrations (10, 40, 90 cm depth), topsoil methane oxidation capacity and soil properties were surveyed at 40 locations along a 16 m grid. As soil properties determine gas flow patterns it was hypothesized that the variability in soil gas composition and the subsequent methanotrophic activity would correspond to the variability of soil properties. Methanotrophic activity was found to be subject to high spatial variability, with values ranging between 0.17 and 9.80 g CH(4)m(-2)h(-1)(.) Considering the current gas production rate of 0.03 g CH(4)m(-2)h(-1), the oxidation capacity at all sampled locations clearly exceeded the flux to the cover, and can be regarded as an effective instrument for mitigating methane fluxes. The methane concentration in the cover showed a high spatial heterogeneity with values between 0.01 and 0.32 vol.% (10 cm depth), 22.52 vol.% (40 cm), and 36.85 vol.% (90 cm). The exposure to methane raised the oxidation capacity, suggested by a statistical correlation to an increase in methane concentration at 90 cm depth. Methane oxidation capacity was further affected by the methanotroph bacteria pH optimum and nutrient availability, and increased with decreasing pH towards neutrality, and increased with soluble ion concentration). Soil methane and carbon dioxide concentration increased with lower flow resistance of the cover, as represented by the soil properties of a reduced bulk density, increase in air capacity and in relative ground level. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Nitrous oxide and methane dynamics in a coral reef lagoon driven by pore water exchange: Insights from automated high-frequency observations

    NASA Astrophysics Data System (ADS)

    O'Reilly, Chiara; Santos, Isaac R.; Cyronak, Tyler; McMahon, Ashly; Maher, Damien T.

    2015-04-01

    Automated cavity ring down spectroscopy was used to make continuous measurements of dissolved methane, nitrous oxide, and carbon dioxide in a coral reef lagoon for 2 weeks (Heron Island, Great Barrier Reef). Radon (222Rn) was used to trace the influence of tidally driven pore water exchange on greenhouse gas dynamics. Clear tidal variation was observed for CH4, which correlated to 222Rn in lagoon waters. N2O correlated to 222Rn during the day only, which appears to be a response to coupled nitrification-denitrification in oxic sediments, fueled by nitrate derived from bird guano. The lagoon was a net source of CH4 and N2O to the atmosphere and a sink for atmospheric CO2. The estimated pore water-derived CH4 and N2O fluxes were 3.2-fold and 24.0-fold greater than the fluxes to the atmosphere. Overall, pore water and/or groundwater exchange were the only important sources of CH4 and major controls of N2O in the coral reef lagoon.

  13. Effects of ammonia on methane oxidation in landfill cover materials.

    PubMed

    Long, Yu-Yang; Liao, Yan; Miao, Jing-Yu; Shen, Dong-Sheng

    2014-01-01

    The effects of ammonia (NH3) on CH4 attenuation in landfill cover materials consisting of landfill cover soil (LCS) and aged municipal solid waste (AMSW), at different CH4 concentrations, were investigated. The CH4 oxidation capacities of LCS and AMSW were found to be significantly affected by the CH4 concentration. The maximum oxidation rates for LCS and AMSW were obtained at CH4 concentrations of 5% and 20%(v/v), respectively, within 20 days. CH4 biological oxidation in AMSW was significantly inhibited by NH3 at low CH4 concentrations (5%, v/v) but highly stimulated at high levels (20% and 50%, v/v). Oxidation in LCS was stimulated by NH3 at all CH4 concentrations due to the higher conversion of the nitrogen in NH3 in AMSW than in LCS. NH3 increases CH4 oxidation in landfill cover materials.

  14. Effects of methane on the microbial populations and oxidation rates in different landfill cover soil columns.

    PubMed

    He, Ruo; Ruan, Aidong; Shen, Dong-Sheng

    2007-05-01

    A considerable fraction of methane produced in landfills is oxidized by landfill cover soils. In this work, microbial populations and oxidation rates developed in response to the presence of methane were studied in three soil columns simulated landfill cover soil environments. The population of aerobic heterotrophic bacteria was highest in the waste soil, middle in the clay soil, and lowest in the red soil. After exposure to methane-rich environments, the populations of methanotrophic bacteria showed increases in the waste and clay soils. The population of methanotrophic bacteria increased from 30.77x10(4) to 141.77x10(4) cfu g d.w.-1 in the middle layer of the waste soil column as a function of exposure to methane for 120 days. The populations of methanotrophic bacteria were correlated with the potential methane oxidation rates in the waste and clay soils, respectively. The topsoil was observed to be dried in the three soil columns. Most of methane oxidation occurred at the depth of between 10 and 20 cm in the waste soil column, while it took place mainly at the depth of between 20 and 30 cm in the clay soil column.

  15. Modelling of stable isotope fractionation by methane oxidation and diffusion in landfill cover soils.

    PubMed

    Mahieu, Koenraad; De Visscher, Alex; Vanrolleghem, Peter A; Van Cleemput, Oswald

    2008-01-01

    A technique to measure biological methane oxidation in landfill cover soils that is gaining increased interest is the measurement of stable isotope fractionation in the methane. Usually to quantify methane oxidation, only fractionation by oxidation is taken into account. Recently it was shown that neglecting the isotope fractionation by diffusion results in underestimation of the methane oxidation. In this study a simulation model was developed that describes gas transport and methane oxidation in landfill cover soils. The model distinguishes between 12CH4, 13CH4, and 12CH3D explicitly, and includes isotope fractionation by diffusion and oxidation. To evaluate the model, the simulations were compared with column experiments from previous studies. The predicted concentration profiles and isotopic profiles match the measured ones very well, with a root mean square deviation (RMSD) of 1.7 vol% in the concentration and a RMSD of 0.8 per thousand in the delta13C value, with delta13C the relative 13C abundance as compared to an international standard. Overall, the comparison shows that a model-based isotope approach for the determination of methane oxidation efficiencies is feasible and superior to existing isotope methods.

  16. Modelling of stable isotope fractionation by methane oxidation and diffusion in landfill cover soils

    SciTech Connect

    Mahieu, Koenraad De Visscher, Alex; Vanrolleghem, Peter A.; Van Cleemput, Oswald

    2008-07-01

    A technique to measure biological methane oxidation in landfill cover soils that is gaining increased interest is the measurement of stable isotope fractionation in the methane. Usually to quantify methane oxidation, only fractionation by oxidation is taken into account. Recently it was shown that neglecting the isotope fractionation by diffusion results in underestimation of the methane oxidation. In this study a simulation model was developed that describes gas transport and methane oxidation in landfill cover soils. The model distinguishes between {sup 12}CH{sub 4}, {sup 13}CH{sub 4}, and {sup 12}CH{sub 3}D explicitly, and includes isotope fractionation by diffusion and oxidation. To evaluate the model, the simulations were compared with column experiments from previous studies. The predicted concentration profiles and isotopic profiles match the measured ones very well, with a root mean square deviation (RMSD) of 1.7 vol% in the concentration and a RMSD of 0.8 per mille in the {delta}{sup 13}C value, with {delta}{sup 13}C the relative {sup 13}C abundance as compared to an international standard. Overall, the comparison shows that a model-based isotope approach for the determination of methane oxidation efficiencies is feasible and superior to existing isotope methods.

  17. Methane flux and oxidation at two types of intermediate landfill covers

    SciTech Connect

    Abichou, Tarek . E-mail: abichou@eng.fsu.edu; Chanton, Jeffery; Powelson, David; Fleiger, Jill; Escoriaza, Sharon; Lei, Yuan; Stern, Jennifer

    2006-07-01

    Methane emissions were measured on two areas at a Florida (USA) landfill using the static chamber technique. Because existing literature contains few measurements of methane emissions and oxidation in intermediate cover areas, this study focused on field measurement of emissions at 15-cm-thick non-vegetated intermediate cover overlying 1-year-old waste and a 45-cm-thick vegetated intermediate cover overlying 7-year-old waste. The 45 cm thick cover can also simulate non-engineered covers associated with older closed landfills. Oxidation of the emitted methane was evaluated using stable isotope techniques. The arithmetic means of the measured fluxes were 54 and 22 g CH{sub 4} m{sup -2} d{sup -1} from the thin cover and the thick cover, respectively. The peak flux was 596 g m{sup -2} d{sup -1} for the thin cover and 330 g m{sup -2} d{sup -1} for the thick cover. The mean percent oxidation was significantly greater (25%) at the thick cover relative to the thin cover (14%). This difference only partly accounted for the difference in emissions from the two sites. Inverse distance weighing was used to describe the spatial variation of flux emissions from each cover type. The geospatial mean flux was 21.6 g m{sup -2} d{sup -1} for the thick intermediate cover and 50.0 g m{sup -2} d{sup -1} for the thin intermediate cover. High emission zones in the thick cover were fewer and more isolated, while high emission zones in the thin cover were continuous and covered a larger area. These differences in the emission patterns suggest that different CH{sub 4} mitigation techniques should be applied to the two areas. For the thick intermediate cover, we suggest that effective mitigation of methane emissions could be achieved by placement of individualized compost cells over high emission zones. Emissions from the thin intermediate cover, on the other hand, can be mitigated by placing a compost layer over the entire area.

  18. Characterization of methane oxidation by a methanotroph isolated from a landfill cover soil, South Korea.

    PubMed

    Lee, Eun-Hee; Yi, Taewoo; Moon, Kyung-Eun; Park, Hyunjung; Ryu, Hee Wook; Cho, Kyung-Suk

    2011-07-01

    A methane-oxidizing bacterium was isolated from the enriched culture of a landfill cover soil. The closest relative of the isolate, designated M6, is Methylocystis sp. Based on a kinetic analysis, the maximum specific methane oxidation rate and saturation constant were 4.93 mmol·g--dry cell weight--1·h⁻¹ and 23 microM, respectively. This was the first time a kinetic analysis was performed using pure methanotrophic culture. The methane oxidation by M6 was investigated in the presence of aromatic (m- and p-xylene and ethylbenzene) or sulfur (hydrogen sulfide, dimethyl sulfide, methanthiol) compounds. The methane oxidation was inhibited by the presence of aromatic or sulfur compounds.

  19. Scaling methane oxidation: from laboratory incubation experiments to landfill cover field conditions.

    PubMed

    Abichou, Tarek; Mahieu, Koenraad; Chanton, Jeff; Romdhane, Mehrez; Mansouri, Imane

    2011-05-01

    Evaluating field-scale methane oxidation in landfill cover soils using numerical models is gaining interest in the solid waste industry as research has made it clear that methane oxidation in the field is a complex function of climatic conditions, soil type, cover design, and incoming flux of landfill gas from the waste mass. Numerical models can account for these parameters as they change with time and space under field conditions. In this study, we developed temperature, and water content correction factors for methane oxidation parameters. We also introduced a possible correction to account for the different soil structure under field conditions. These parameters were defined in laboratory incubation experiments performed on homogenized soil specimens and were used to predict the actual methane oxidation rates to be expected under field conditions. Water content and temperature corrections factors were obtained for the methane oxidation rate parameter to be used when modeling methane oxidation in the field. To predict in situ measured rates of methane with the model it was necessary to set the half saturation constant of methane and oxygen, K(m), to 5%, approximately five times larger than laboratory measured values. We hypothesize that this discrepancy reflects differences in soil structure between homogenized soil conditions in the lab and actual aggregated soil structure in the field. When all of these correction factors were re-introduced into the oxidation module of our model, it was able to reproduce surface emissions (as measured by static flux chambers) and percent oxidation (as measured by stable isotope techniques) within the range measured in the field. Copyright © 2010 Elsevier Ltd. All rights reserved.

  20. Scaling methane oxidation: From laboratory incubation experiments to landfill cover field conditions

    SciTech Connect

    Abichou, Tarek; Mahieu, Koenraad; Chanton, Jeff; Romdhane, Mehrez; Mansouri, Imane

    2011-05-15

    Evaluating field-scale methane oxidation in landfill cover soils using numerical models is gaining interest in the solid waste industry as research has made it clear that methane oxidation in the field is a complex function of climatic conditions, soil type, cover design, and incoming flux of landfill gas from the waste mass. Numerical models can account for these parameters as they change with time and space under field conditions. In this study, we developed temperature, and water content correction factors for methane oxidation parameters. We also introduced a possible correction to account for the different soil structure under field conditions. These parameters were defined in laboratory incubation experiments performed on homogenized soil specimens and were used to predict the actual methane oxidation rates to be expected under field conditions. Water content and temperature corrections factors were obtained for the methane oxidation rate parameter to be used when modeling methane oxidation in the field. To predict in situ measured rates of methane with the model it was necessary to set the half saturation constant of methane and oxygen, K{sub m}, to 5%, approximately five times larger than laboratory measured values. We hypothesize that this discrepancy reflects differences in soil structure between homogenized soil conditions in the lab and actual aggregated soil structure in the field. When all of these correction factors were re-introduced into the oxidation module of our model, it was able to reproduce surface emissions (as measured by static flux chambers) and percent oxidation (as measured by stable isotope techniques) within the range measured in the field.

  1. [Effects of methane stress on oxidation rates and microbial community structures in different landfill cover soils].

    PubMed

    He, Ruo; Jiang, Chen-jing; Wang, Jing; Gao, Qing-jun; Shen, Dong-sheng

    2008-12-01

    As compared with the ordinary landfill cover material, clay soil, the effect of methane stress on oxidation rate and microbial community structure was investigated in waste soil (material from biologically treated municipal solid waste). The results showed that the moisture content of the clay soil was low, due to the low water retaining capacity. As environmental temperature and rainfall changed, the clay soil caked and inhibited methanotrophs growth. However, with a high organic matter, water-holding capacity and porosity, the waste soil provided a favor condition for methanotrophs growth and propagation. After exposure to methane flow for 120 days, methane oxidation potential in the middle and bottom layers of the waste soil column increased to 11.25-13.48 micromol/(g x h), which was 10.4-24.5 times higher than that in clay soil column. The topsoils were both found to be dried and inhibit methane oxidation. Methane oxidation (removal) efficiency by the waste soil column reached 48.3% at the end of the experiment, which was 5-6 times higher than that by the clay soil column. The amounts of the phospholipid fatty acid (PLFA) biomarks 16:1 omega 8c and 18:1 omega 8c for Type I and II methanotrophs, respectively, showed that a strong linear relationship was observed between methane oxidation potential and PLFA 18:1 omega 8c content in soil samples.

  2. Isotope fractionation effects by diffusion and methane oxidation in landfill cover soils

    NASA Astrophysics Data System (ADS)

    de Visscher, Alex; de Pourcq, Ingrid; Chanton, Jeffrey

    2004-09-01

    When the open system isotope method has been used to determine the methane oxidation efficiency of a landfill cover soil, it has been assumed that gas transport from the landfill is primarily driven by advection, a mechanism that is not associated with isotopic fractionation. A controlled laboratory experiment revealed that this approach underestimated the methane oxidation efficiency because it underestimated the importance of molecular diffusion during gas transport. In a worst-case scenario laboratory column experiment where diffusion was an important gas transport mode, a comparison between a mass balance and the open system isotope method revealed that the latter underestimated methane oxidation by a factor 2 to 4. The vertical profile of the δ13C value of methane in the column confirmed that isotope fractionation associated with gas transport occurred. Similar profiles were observed in the field, but the effect was less pronounced. It is concluded that the isotope method as currently applied produces a conservative estimate of methane oxidation by landfill cover soils.

  3. The estimation of methane emissions from landfills with different cover systems

    NASA Astrophysics Data System (ADS)

    Park, S.; Lee, K.; Sung, K.

    2006-12-01

    Methane is a very potent greenhouse gas, second only to CO2 as an anthropogenic contributor to global warming. Landfills are important anthropogenic source in the CH4 emissions. Microbially mediated CH4 oxidation in landfills with conventional soil covers can serve as an efficient biological sink. Methane from modern sanitary landfills equipped with composite covers and gas collection system is vented directly to the atmosphere, except for some of the largest landfills at which it is collected and burned. However, previous laboratory research has shown that biofilters have the potential to reduce CH4 emissions from landfills with modern composite covers. In this study a CH4 emission model was developed. The model used the calculated CH4 oxidation rates to estimate CH4 emissions from landfills constructed with conventional soil covers, modern composite covers, and modern composite covers plus biofilters. According to the CH4 emission rates predicted by CH4 emission model, it was estimated that 90% of the generated CH4 was emitted to the atmosphere for landfills with modern composite cover. For landfills with modern composite cover plus biofilters, an average of only 9% of the generated CH4 was estimated to be emitted. For landfills with conventional covers, an average of 83% of the generated CH4 was estimated to be emitted. By comparing the CH4 emission rates from three different landfill types, the use of a properly managed biofilter should be an effective technique to reduce CH4 emissions from landfills.

  4. An analytical model for estimating the reduction of methane emission through landfill cover soils by methane oxidation.

    PubMed

    Yao, Yijun; Su, Yao; Wu, Yun; Liu, Weiping; He, Ruo

    2015-01-01

    Landfill is an important source of atmospheric methane (CH4). In this study, the development and partial validation are presented for an analytical model for predicting the reduction of CH4 emission in landfill cover soils by CH4 oxidation. The model combines an analytic solution of a coupled oxygen (O2) and CH4 soil gas transport in landfill covers with a piecewise first-order aerobic biodegradation, including the influences of environmental factors such as cover soil thickness, CH4 oxidation and CH4 production rate. Comparison of soil gas concentration profiles with a soil column experiment is provided for a partial validation, and then this model is applied to predict the reduction of CH4 emission through landfill covers in several other cases. A discussion is provided to illustrate the roles of soil layer thickness, reaction rate constant for CH4 oxidation and CH4 production rate in determining CH4 emissions. The results suggest that the increase of cover soil thickness cannot always increase CH4 oxidation rates or removal efficiency, which becomes constant if the thickness of landfill cover soil is larger than a limit. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Effect of substrate interaction on oxidation of methane and benzene in enriched microbial consortia from landfill cover soil.

    PubMed

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2011-01-01

    The interaction of methane and benzene during oxidation in enriched methane-oxidizing consortium (MOC) and in benzene-oxidizing consortium (BOC) from landfill cover soil was characterized. Oxidation of both methane and benzene occurred in the MOC due to the coexistence of bacteria responsible for benzene oxidation, as well as methanotrophs, whereas in the BOC, only benzene was oxidized, not methane. Methane oxidation rates in the MOC were decreased with increasing benzene/methane ratio (mol/mol), indicating its methane oxidation was inhibited by the benzene coexistence. Benzene oxidation rates in the MOC, however, were increased with increasing benzene/methane ratio. The benzene oxidation in the BOC was not affected by the coexistence of methane or by the ratio of methane/benzene ratio (mol/mol). No effect of methane or benzene was found on the dynamics of functional genes, such as particulate methane monooxygenase and toluene monooxygenase, in association with oxidation of methane and benzene in the MOC and BOC.

  6. Methane oxidation in landfill cover soils, is a 10% default value reasonable?

    PubMed

    Chanton, Jeffrey P; Powelson, David K; Green, Roger B

    2009-01-01

    We reviewed literature results from 42 determinations of the fraction of methane oxidized and 30 determinations of methane oxidation rate in a variety of soil types and landfill covers. Both column measurements and in situ field measurements were included. The means for the fraction of methane oxidized on transit across the soil covers ranged from 22 to 55% from clayey to sandy material. Mean values for oxidation rate ranged from 3.7 to 6.4 mol m(-2) d(-1) (52-102 g m(-2) d(-1)) for the different soil types. The overall mean fraction oxidized across all studies was 36% with a standard error of 6%. The overall mean oxidation rate across all studies was 4.5 mol m(-2) d(-1) +/- 1.0 (72 +/- 16 g m(-2)d(-1)). For the subset of 15 studies conducted over an annual cycle the fraction of methane oxidized ranged from 11 to 89% with a mean value of 35 +/- 6%, nearly identical to the overall mean. Nine of these studies were conducted in north Florida at 30 degrees N latitude and had a fraction oxidized of 27 +/- 4%. Five studies were conducted in northern Europe ( approximately 50-55 degrees N) and exhibited an average of 54 +/- 14%. One study, conducted in New Hampshire, had a value of 10%. The results indicate that the fraction of methane oxidized in landfill greater than the default value of 10%. Of the 42 determinations of methane oxidation reported, only four report values of 10% or less.

  7. Lagoons and Oxidation Ponds.

    ERIC Educational Resources Information Center

    O'Brien, W. J.

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. This review covers lagoons and oxidation ponds, and it includes some areas such as improving the effluents from ponds, stabilization ponds, aerated lagoons, and oxidation ditches. A list of 36 references is also presented. (HM)

  8. Lagoons and Oxidation Ponds.

    ERIC Educational Resources Information Center

    O'Brien, W. J.

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. This review covers lagoons and oxidation ponds, and it includes some areas such as improving the effluents from ponds, stabilization ponds, aerated lagoons, and oxidation ditches. A list of 36 references is also presented. (HM)

  9. An integrated physical and biological model for anaerobic lagoons.

    PubMed

    Wu, Binxin; Chen, Zhenbin

    2011-04-01

    A computational fluid dynamics (CFD) model that integrates physical and biological processes for anaerobic lagoons is presented. In the model development, turbulence is represented using a transition k-ω model, heat conduction and solar radiation are included in the thermal model, biological oxygen demand (BOD) reduction is characterized by first-order kinetics, and methane yield rate is expressed as a linear function of temperature. A test of the model applicability is conducted in a covered lagoon digester operated under tropical climate conditions. The commercial CFD software, ANSYS-Fluent, is employed to solve the integrated model. The simulation procedures include solving fluid flow and heat transfer, predicting local resident time based on the converged flow fields, and calculating the BOD reduction and methane production. The simulated results show that monthly methane production varies insignificantly, but the time to achieve a 99% BOD reduction in January is much longer than that in July.

  10. Numerical modelling of methane oxidation efficiency and coupled water-gas-heat reactive transfer in a sloping landfill cover.

    PubMed

    Feng, S; Ng, C W W; Leung, A K; Liu, H W

    2017-10-01

    Microbial aerobic methane oxidation in unsaturated landfill cover involves coupled water, gas and heat reactive transfer. The coupled process is complex and its influence on methane oxidation efficiency is not clear, especially in steep covers where spatial variations of water, gas and heat are significant. In this study, two-dimensional finite element numerical simulations were carried out to evaluate the performance of unsaturated sloping cover. The numerical model was calibrated using a set of flume model test data, and was then subsequently used for parametric study. A new method that considers transient changes of methane concentration during the estimation of the methane oxidation efficiency was proposed and compared against existing methods. It was found that a steeper cover had a lower oxidation efficiency due to enhanced downslope water flow, during which desaturation of soil promoted gas transport and hence landfill gas emission. This effect was magnified as the cover angle and landfill gas generation rate at the bottom of the cover increased. Assuming the steady-state methane concentration in a cover would result in a non-conservative overestimation of oxidation efficiency, especially when a steep cover was subjected to rainfall infiltration. By considering the transient methane concentration, the newly-modified method can give a more accurate oxidation efficiency. Copyright © 2017. Published by Elsevier Ltd.

  11. Methane oxidation in a boreal climate in an experimental landfill cover composed from mechanically-biologically treated waste.

    PubMed

    Einola, J-K M; Sormunen, K M; Rintala, J A

    2008-12-15

    The present study evaluated microbial methane (CH4) oxidation in a boreally located outdoor landfill lysimeter (volume 112 m3, height 3.9 m) filled with mechanically-biologically treated waste (MBT residual) and containing a cover layer made from the same MBT residual. The calculations based on gas emission and pore gas measurements showed that, between April and October 2005, a significant proportion (> 96%) of the methane produced (< 23 l CH4 m(-2) d(-1)) in the lysimeter was oxidized. Methane was oxidized mainly at the depths of 35-75 cm, as indicated by the upward decrease both in the methane concentration and in the methane-to-carbon dioxide ratio in the pore gas. Lower methane oxidation (< 0.8 CH4 m(-2) d(-1); this was < 22% of the methane produced) was observed only during the coldest time of the year (January 2006), apparently due to the fall in temperature at the depths of 25-70 cm (from 9-25 degrees C during April to October to 2-9 degrees C in January). Unexpectedly, the highest methane oxidation potential (MOP) was observed in samples from the top layer where exposure to methane was low. Overall, the results show that MBT residual is a suitable support medium for methane oxidation in landfill covers in field conditions in a boreal climate.

  12. Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers

    SciTech Connect

    Albanna, Muna; Warith, Mostafa; Fernandes, Leta

    2010-02-15

    In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH{sub 4}) oxidation process were examined. The investigation was performed on compost experiments incubated with CH{sub 4} and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH{sub 4} oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 deg. C without any NMOCs the V{sub max} value was 35.0 mug CH{sub 4}h{sup -1}g{sub wetwt}{sup -1}. This value was reduced to 19.1 mug CH{sub 4}h{sup -1}g{sub wetwt}{sup -1} when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH{sub 4} in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.

  13. Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers.

    PubMed

    Albanna, Muna; Warith, Mostafa; Fernandes, Leta

    2010-02-01

    In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH4) oxidation process were examined. The investigation was performed on compost experiments incubated with CH4 and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH4 oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 degrees C without any NMOCs the V(max) value was 35.0 microg CH4 h(-1)gwet wt(-1). This value was reduced to 19.1 microg CH4 h(-1) gwet wt(-1) when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH4 in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.

  14. Emissions of ammonia, nitrous oxide and methane from cattle manure heaps: effect of compaction and covering

    NASA Astrophysics Data System (ADS)

    Chadwick, D. R.

    The effect of compaction and covering during storage of beef cattle ( Bos taurus) farmyard manure (FYM) on ammonia (NH 3), nitrous oxide (N 2O) and methane (CH 4) emissions was determined. Gaseous emission measurements were made over three separate storage periods of between 90 and 109 days. The effect of the different storage treatments on manure chemical composition was also determined. Compaction was carried out as the manure was put into store and the compacted manures covered with plastic sheeting. Compaction and covering significantly reduced NH 3 emissions from manure by over 90% during the first summer storage period (P<0.05). Over the subsequent storage periods NH 3 emissions from the FYM were small and unaffected by storage treatment. However, during the second storage period heavy and persistent rainfall during heap establishment and the following week appeared to reduce NH 3 emissions markedly. The low ammonium-N content of the FYM in the third storage period may have reduced the risk of NH 3 emission and reduced the relative effect of the compaction/covering treatment. Compaction and covering also significantly reduced N 2O emissions from cattle FYM (P<0.05) by ca. 30% during the first storage period. Subsequent N 2O emissions were unaffected by treatment. Methane emissions from cattle FYM were unaffected by treatment over the first storage period and were decreased by compaction in the second storage period yet was increased by compaction during the third storage period. It would appear that compacting and covering manure heaps does have the potential to reduce emissions of both NH 3 and N 2O when the manure contains relatively high ammonium-N contents. Additional benefits are that N and K are retained in the manure heap for agronomic benefit.

  15. Modeling of methane oxidation in landfill cover soil using an artificial neural network.

    PubMed

    Abushammala, Mohammed F M; Basri, Noor Ezlin Ahmad; Elfithri, Rahmah; Younes, Mohammad K; Irwan, Dani

    2014-02-01

    Knowing the fraction of methane (CH4) oxidized in landfill cover soils is an important step in estimating the total CH4 emissions from any landfill. Predicting CH4 oxidation in landfill cover soils is a difficult task because it is controlled by a number of biological and environmental factors. This study proposes an artificial neural network (ANN) approach using feedforward backpropagation to predict CH4 oxidation in landfill cover soil in relation to air temperature, soil moisture content, oxygen (O2) concentration at a depth of 10 cm in cover soil, and CH4 concentration at the bottom of cover soil. The optimum ANN model giving the lowest mean square error (MSE) was configured from three layers, with 12 and 9 neurons at the first and the second hidden layers, respectively, log-sigmoid (logsig) transfer function at the hidden and output layers, and the Levenberg-Marquardt training algorithm. This study revealed that the ANN oxidation model can predict CH4 oxidation with a MSE of 0.0082, a coefficient of determination (R2) between the measured and predicted outputs of up to 0.937, and a model efficiency (E) of 0.8978. To conclude, further developments of the proposed ANN model are required to generalize and apply the model to other landfills with different cover soil properties.

  16. Capacity for biodegradation of CFCs and HCFCs in a methane oxidative counter-gradient laboratory system simulating landfill soil covers.

    PubMed

    Scheutz, Charlotte; Kjeldsen, Peter

    2003-11-15

    The attenuation of methane and four chlorofluorocarbons was investigated in a dynamic methane and oxygen counter-gradient system simulating a landfill soil cover. Soil was sampled at Skellingsted Landfill, Denmark. The soil columns showed a high capacity of methane oxidation with oxidation rates of 210 g m(-2) d(-1) corresponding to a removal efficiency of 81%. CFC-11 and to a lesser extent also CFC-12 were degraded in the active soil columns. The average removal efficiency was 90% and 30% for CFC-11 and CFC-12, respectively. Soil gas concentration profiles indicated that the removal was due to anaerobic degradation, which was verified in anaerobic batch experiments where CFC-11 was rapidly degraded. HCFC-21 and HCFC-22 were also degraded in active soil columns (61% and 41%, respectively), but compared to the CFCs, the degradation was located in the upper oxic part of the column with overlapping gradients of methane and oxygen. High oxidation rates of methane and HCFCs were obtained in soil microcosms incubated with methane. When increasing the column inlet flow, the oxidation zone was moved upward in the column, and the removal efficiency of methane and HCFCs decreased. The removal of CFCs was, however, less affected since the anaerobic zone expanded with increasing inlet flow rates. This study demonstrates the complexity of landfill soil cover systems and shows that both anaerobic and aerobic bacteria may play a very important role in reducing the emission of not only methane but also trace components into the atmosphere.

  17. Adsorption and transport of methane in landfill cover soil amended with waste-wood biochars.

    PubMed

    Sadasivam, Bala Yamini; Reddy, Krishna R

    2015-08-01

    The natural presence of methane oxidizing bacteria (MOB) in landfill soils can stimulate the bio-chemical oxidation of CH4 to CO2 and H2O under suitable environmental conditions. This mechanism can be enhanced by amending the landfill cover soil with organic materials such as biochars that are recalcitrant to biological degradation and are capable of adsorbing CH4 while facilitating the growth and activity of MOB within their porous structure. Several series of batch and small-scale column tests were conducted to quantify the CH4 sorption and transport properties of landfill cover soil amended with four types of waste hardwood biochars under different levels of amendment percentages (2, 5 and 10% by weight), exposed CH4 concentrations (0-1 kPa), moisture content (dry, 25% and 75% water holding capacity), and temperature (25, 35 and 45 °C). The linear forms of the pseudo second-order kinetic model and the Langmuir isotherm model were used to determine the kinetics and the maximum CH4 adsorption capacity of cover materials. The maximum CH4 sorption capacity of dry biochar-amended soils ranged from 1.03 × 10(-2) to 7.97 × 10(-2) mol kg(-1) and exhibited a ten-fold increase compared to that of soil with 1.9 × 10(-3) mol kg(-1). The isosteric heat of adsorption for soil was negative and ranged from -30 to -118 kJ/mol, while that of the biochar-amended soils was positive and ranged from 24 to 440 kJ/mol. The CH4 dispersion coefficients for biochar-amended soils obtained through predictive transport modeling indicated that amending the soil with biochar enhanced the methane transport rates by two orders of magnitude, thereby increasing their potential for enhanced exchange of gases within the cover system. Overall, the use of hardwood biochars as a cover soil amendment to reduce methane emissions from landfills appears to be a promising alternative to conventional soil covers.

  18. Biodegradation of methane, benzene, and toluene by a consortium MBT14 enriched from a landfill cover soil.

    PubMed

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2013-01-01

    In this study, landfill cover soil was used as an inoculum source to enrich a methane, benzene, and toluene-degrading consortium MBT14. Under a single substrate, the maximum degradation rates of methane, benzene and toluene were 1.96, 0.15, and 0.77 mmole g-DCW(-1) h(-1), respectively. Although the coexistence of benzene and toluene inhibited the methane degradation rates, the consortium was able to simultaneously degrade methane, benzene and toluene. Methane had an insignificant effect on benzene or toluene degradation. Based on 16S rDNA sequencing analysis, Cupriavidus spp. are dominant in the consortium MBT14. The combined results of this study indicate that the consortium MBT 14 is a promising bioresource for removing CH(4), benzene, and toluene from a variety of environments.

  19. Ammonium-dependent regulation of aerobic methane-consuming bacteria in landfill cover soil by leachate irrigation.

    PubMed

    Lü, Fan; He, Pinjing; Guo, Min; Yang, Na; Shao, Liming

    2012-01-01

    The impacts of landfill leachate irrigation on methane oxidation activities and methane-consuming bacteria populations were studied by incubation of landfill cover soils with leachate and (NH4)2SO4 solution at different ammonium concentrations. The community structures and abundances of methane-oxidizing bacteria (MOB) and ammonia-oxidizing bacteria (AOB) were examined by PCR-DGGE and real-time PCR. Compared with the pure (NH4)2SO4 solution, leachate addition was found to have a positive effect on methane oxidation activity. In terms of the irrigation amount, ammonium in leachate was responsible for the actual inhibition of leachate. The extent of inhibitory effect mainly depended on its ammonium concentration. The suppression of the predominant methane-consuming bacteria, type I MOB, was responsible for the decreased methane oxidation activity by ammonium inhibition. Methane-consuming bacteria responded diversely in abundance to ammonium. The abundance of type I MOB decreased by fivefold; type II MOB showed stimulation response of fivefold magnification upon the first addition but lessened to be lower than the original level after the second addition; the amount of AOB was stimulated to increase for 20-30 times gradually. Accumulated nitrate from nitrification strengthened the ammonium inhibition on type I and type II MOB, as a result, repetitive irrigation was unfavorable for methane oxidation.

  20. Consuming un-captured methane from landfill using aged refuse bio-cover.

    PubMed

    Lou, Ziyang; Wang, Li; Zhao, Youcai

    2011-02-01

    A novel simulated bio-cover was developed to facilitate the biological methane oxidation process using aged refuse and aged sludge from landfill. It was found that 78.7% and 66.9% of CH(4) could be removed, with the aged refuse: aged sludge (w/w%) ratio of 7:3 and 6:4 in bio-cover system, respectively. The maximum CH(4) removal rate could reach 100%, when the aged refuse with the disposal time more than 14 years were applied in bio-cover. Some controlled factors for the methanotrophic activity, i.e. moisture, Eh and organic matter content, were also investigated. It was found that CH(4) oxidation rate increased greatly, when the moisture content and organic matter were increased from 6.0%, 4.8% to 8.0%, 9.5%, respectively. The optimum conditions for this bio-cover system was found to be as follows: aged refuse: aged sludge ratio of 7:3, the moisture content of 8-9%, Eh of 104-108 mV and organic matter of 9.5%. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Determination of environmental factors influencing methane oxidation in a sandy landfill cover soil.

    PubMed

    Park, J R; Moon, S; Ahn, Y M; Kim, J Y; Nam, K

    2005-01-01

    It is advantageous to use coarse soils as landfill cover because they allow better aeration of the biologically active zone. In this study, therefore, patterns of methane oxidation were investigated under various environmental conditions including soil moisture content, temperature, and the addition of NH4+ in a sandy landfill cover soil. The kinetics of CH4 oxidation was also studied at different moisture contents and temperatures. Soil moisture content of 10% (wt/wt) resulted in the maximum CH4 oxidation rate (19.2-22.4 nmol gsoil DW(-1) min(-1)). A Vmax value was not significantly different when the moisture content was more than 10%, but a Km value increased from 5.23 to 75.24 microM as the moisture content increased. The ratio of Vmax to Km was the highest at 10% moisture content. The CH4 oxidation rate increased as the incubation temperature increased, and Q10 values and optimum temperature were determined to be 2.57-2.69 and 30 degrees C, respectively. Both Vmax and Km values decreased at the temperatures below and above 30 degrees C. The addition of various levels of NH4+ resulted in increased or decreased CH4 oxidation rates, however, the initiation of appreciable CH4 oxidation was delayed with increasing amounts of NH4+ application in all samples tested. Among the environmental variables tested, moisture content control seems to be the most important and an efficient means of managing methane oxidation when sandy soils are used in landfill cover.

  2. Modeling the effects of vegetation on methane oxidation and emissions through soil landfill final covers across different climates.

    PubMed

    Abichou, Tarek; Kormi, Tarek; Yuan, Lei; Johnson, Terry; Francisco, Escobar

    2015-02-01

    Plant roots are reported to enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil as well as the supply of methane to bacteria. Therefore, methane oxidation can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This study consisted of using a numerical model that combines flow of water and heat with gas transport and oxidation in soils, to simulate methane emission and oxidation through simulated vegetated and non-vegetated landfill covers under different climatic conditions. Different simulations were performed using different methane loading flux (5-200 g m(-2) d(-1)) as the bottom boundary. The lowest modeled surface emissions were always obtained with vegetated soil covers for all simulated climates. The largest differences in simulated surface emissions between the vegetated and non-vegetated scenarios occur during the growing season. Higher average yearly percent oxidation was obtained in simulations with vegetated soil covers as compared to non-vegetated scenario. The modeled effects of vegetation on methane surface emissions and percent oxidation were attributed to two separate mechanisms: (1) increase in methane oxidation associated with the change of the physical properties of the upper vegetative layer and (2) increase in organic matter associated with vegetated soil layers. Finally, correlations between percent oxidation and methane loading into simulated vegetated and non-vegetated covers were proposed to allow decision makers to compare vegetated versus non-vegetated soil landfill covers. These results were obtained using a modeling study with several simplifying assumptions that do not capture the complexities of vegetated soils under field conditions.

  3. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil.

    PubMed

    Schroth, M H; Eugster, W; Gómez, K E; Gonzalez-Gil, G; Niklaus, P A; Oester, P

    2012-05-01

    Landfills are a major anthropogenic source of the greenhouse gas methane (CH(4)). However, much of the CH(4) produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH(4) fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH(4) ingress (loading) from the waste body at selected locations. Fluxes of CH(4) into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH(4) concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH(4) fluxes and CH(4) loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH(4) oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH(4) emissions from the test section (daily mean up to ∼91,500μmolm(-2)d(-1)), whereas flux-chamber measurements and CH(4) concentration profiles indicated that at the majority of locations the cover soil was a net sink for atmospheric CH(4) (uptake up to -380μmolm(-2)d(-1)) during the experimental period. Methane concentration profiles also indicated strong variability in CH(4) loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v(max)∼13mmolL(-1)(soil air)h(-1)) at a location with substantial CH(4) loading. Our results provide a basis to assess spatial and temporal variability of CH(4) dynamics in the complex terrain of a landfill-cover soil. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil

    SciTech Connect

    Schroth, M.H.; Eugster, W.; Gomez, K.E.; Gonzalez-Gil, G.; Niklaus, P.A.; Oester, P.

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer We quantify above- and below-ground CH{sub 4} fluxes in a landfill-cover soil. Black-Right-Pointing-Pointer We link methanotrophic activity to estimates of CH{sub 4} loading from the waste body. Black-Right-Pointing-Pointer Methane loading and emissions are highly variable in space and time. Black-Right-Pointing-Pointer Eddy covariance measurements yield largest estimates of CH{sub 4} emissions. Black-Right-Pointing-Pointer Potential methanotrophic activity is high at a location with substantial CH{sub 4} loading. - Abstract: Landfills are a major anthropogenic source of the greenhouse gas methane (CH{sub 4}). However, much of the CH{sub 4} produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH{sub 4} fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH{sub 4} ingress (loading) from the waste body at selected locations. Fluxes of CH{sub 4} into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH{sub 4} concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH{sub 4} fluxes and CH{sub 4} loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH{sub 4} oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH{sub 4} emissions from the test section (daily mean up to {approx}91,500 {mu}mol m{sup -2} d{sup -1}), whereas flux-chamber measurements and CH{sub 4} concentration profiles indicated that at the majority of locations the cover soil was a

  5. Methane oxidation in a landfill cover soil reactor: Changing of kinetic parameters and microorganism community structure.

    PubMed

    Xing, Zhi L; Zhao, Tian T; Gao, Yan H; Yang, Xu; Liu, Shuai; Peng, Xu Y

    2017-02-23

    Changing of CH4 oxidation potential and biological characteristics with CH4 concentration was studied in a landfill cover soil reactor (LCSR). The maximum rate of CH4 oxidation reached 32.40 mol d(-1) m(-2) by providing sufficient O2 in the LCSR. The kinetic parameters of methane oxidation in landfill cover soil were obtained by fitting substrate diffusion and consumption model based on the concentration profile of CH4 and O2. The values of [Formula: see text] (0.93-2.29%) and [Formula: see text] (140-524 nmol kgsoil-DW(-1)·s(-1)) increased with CH4 concentration (9.25-20.30%), while the values of [Formula: see text] (312.9-2.6%) and [Formula: see text] (1.3 × 10(-5) to 9.0 × 10(-3) nmol mL(-1) h(-1)) were just the opposite. MiSeq pyrosequencing data revealed that Methylobacter (the relative abundance was decreased with height of LCSR) and Methylococcales_unclassified (the relative abundance was increased expect in H 80) became the key players after incubation with increasing CH4 concentration. These findings provide information for assessing CH4 oxidation potential and changing of biological characteristics in landfill cover soil.

  6. Potential methane production and oxidation in soil reclamation covers of an oil sands mining site in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Pum, Lisa; Reichenauer, Thomas; Germida, Jim

    2015-04-01

    Anthropogenic activities create a number of significant greenhouse gases and thus potentially contribute to global warming. Methane production is significant in some agricultural production systems and from wetlands. In soil, methane can be oxidised by methanotrophic bacteria. However, little is known about methane production and oxidation in oil sand reclamation covers. The purpose of this study was to investigate methane production and oxidation potential of tailing sands and six different reclamation layers of oil sands mining sites in Alberta, Canada. Methane production and oxidation potential were investigated in laboratory scale microcosms through continuous headspace analysis using gas chromatography. Samples from a reclamation layer were collected at the Canadian Natural Resources Limited (CNRL) reclamation site at depths of 0-10 cm, 10-20 cm and 20-40 cm in October 2014. In addition, tailing sands provided by Suncor Energy Inc. and soil from a CNRL wetland were studied for methane production. Samples were dried, crushed and sieved to 4 mm, packed into serum bottle microcosms and monitored for eight weeks. Methane production potential was assessed by providing an anoxic environment and by adjusting the samples to a moisture holding capacity of 100 %. Methane oxidation potential was examined by an initial application of 2 vol % methane to the microcosms and by adjusting the samples to a moisture holding capacity of 50 %. Microcosm headspace gas was analysed for methane, carbon dioxide, nitrous oxide and oxygen. All experiments were carried out in triplicates, including controls. SF6 and Helium were used as internal standards to detect potential leaks. Our results show differences for methane production potential between the soil depths, tailing sands and wetlands. Moreover, there were differences in the methane oxidation potential of substrate from the three depths investigated and between the reclamation layers. In conclusion, the present study shows that

  7. Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests.

    PubMed

    Gómez, K E; Gonzalez-Gil, G; Lazzaro, A; Schroth, M H

    2009-09-01

    Methane (CH(4)) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH(4) to the atmosphere. To quantify in situ rates of CH(4) oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH(4), O(2) and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH(4) with either Ar or CH(4) itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH(4) oxidation. The maximum calculated first-order rate constant was 24.8+/-0.8 h(-1) at location 1 and 18.9+/-0.6 h(-1) at location 2. In general, location 2 had higher background CH(4) concentrations in vertical profile samples than location 1. High background CH(4) concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH(4) in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH(4) oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH(4) oxidation in a landfill-cover soil when background CH(4) concentrations were low.

  8. Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests

    SciTech Connect

    Gomez, K.E. Gonzalez-Gil, G.; Lazzaro, A.; Schroth, M.H.

    2009-09-15

    Methane (CH{sub 4}) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH{sub 4} to the atmosphere. To quantify in situ rates of CH{sub 4} oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH{sub 4}, O{sub 2} and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH{sub 4} with either Ar or CH{sub 4} itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH{sub 4} oxidation. The maximum calculated first-order rate constant was 24.8 {+-} 0.8 h{sup -1} at location 1 and 18.9 {+-} 0.6 h{sup -1} at location 2. In general, location 2 had higher background CH{sub 4} concentrations in vertical profile samples than location 1. High background CH{sub 4} concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH{sub 4} in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH{sub 4} oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH{sub 4} oxidation in a landfill-cover soil when background CH{sub 4} concentrations were low.

  9. Brazil The Duck Lagoon

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Multi-angle Imaging SpectroRadiometer (MISR) image of Brazil covers an area of about 298 kilometers x 358 kilometers, and was captured by the instrument's vertical-viewing (nadir) camera on December 27, 2001. The 'Lagoa dos Patos', in the Brazilian state of Rio Grande do Sul, translates to 'the Duck Lagoon'. It was named by 16th century Jesuit settlers, who asked the King of Spain to grant them title to the lagoon so that they could breed ducks. The King consented, but revoked his edict when he discovered that the 'duck-pond' (measuring about 14,000 square kilometers) was one of the largest lagoonal systems in the world. Note the sediment plume emanating from the southern end of the lagoon. Sailors in the 16th century imagined this outlet to be the mouth of a large river. Early Portuguese explorers mistook the entrance to the lagoon for the mouth of a great river and called it the Rio Grande. A series of wave-like points and curls form 'cusps' on the inner shores of the lagoon. The lagoon's characteristics change with short-term tide-induced cyclic perturbations, and with longer term large scale meteorological conditions. The distinctive wavelike 'cusps' along the inner shores result from the circulation, erosion and accumulation of sediments driven by wind and tidal action. The El Nino Southern Oscillation (ENSO) circulation affects precipitation amount and continental runoff, thereby changing the contents of the lagoon waters. High rainfall and increased freshwater discharge during El Nino events correspond with elevated dissolved nutrient concentrations and increased phytoplankton growth. La Nina years are dry and the associated low rainfall reduces the freshwater recharge to the lagoon, causing an increase in salinity. Occasional blooms of toxic cyanobacteria (Microcystis aeruginosa), have been registered in the lagoon when nutrient concentrations are elevated. A number of reeds and grasses are important to the lagoon estuary, including widgeon grass

  10. Brazil The Duck Lagoon

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This Multi-angle Imaging SpectroRadiometer (MISR) image of Brazil covers an area of about 298 kilometers x 358 kilometers, and was captured by the instrument's vertical-viewing (nadir) camera on December 27, 2001. The 'Lagoa dos Patos', in the Brazilian state of Rio Grande do Sul, translates to 'the Duck Lagoon'. It was named by 16th century Jesuit settlers, who asked the King of Spain to grant them title to the lagoon so that they could breed ducks. The King consented, but revoked his edict when he discovered that the 'duck-pond' (measuring about 14,000 square kilometers) was one of the largest lagoonal systems in the world. Note the sediment plume emanating from the southern end of the lagoon. Sailors in the 16th century imagined this outlet to be the mouth of a large river. Early Portuguese explorers mistook the entrance to the lagoon for the mouth of a great river and called it the Rio Grande. A series of wave-like points and curls form 'cusps' on the inner shores of the lagoon. The lagoon's characteristics change with short-term tide-induced cyclic perturbations, and with longer term large scale meteorological conditions. The distinctive wavelike 'cusps' along the inner shores result from the circulation, erosion and accumulation of sediments driven by wind and tidal action. The El Nino Southern Oscillation (ENSO) circulation affects precipitation amount and continental runoff, thereby changing the contents of the lagoon waters. High rainfall and increased freshwater discharge during El Nino events correspond with elevated dissolved nutrient concentrations and increased phytoplankton growth. La Nina years are dry and the associated low rainfall reduces the freshwater recharge to the lagoon, causing an increase in salinity. Occasional blooms of toxic cyanobacteria (Microcystis aeruginosa), have been registered in the lagoon when nutrient concentrations are elevated. A number of reeds and grasses are important to the lagoon estuary, including widgeon grass

  11. A fully coupled model for water-gas-heat reactive transport with methane oxidation in landfill covers.

    PubMed

    Ng, C W W; Feng, S; Liu, H W

    2015-03-01

    Methane oxidation in landfill covers is a complex process involving water, gas and heat transfer as well as microbial oxidation. The coupled phenomena of microbial oxidation, water, gas, and heat transfer are not fully understood. In this study, a new model is developed that incorporates water-gas-heat coupled reactive transport in unsaturated soil with methane oxidation. Effects of microbial oxidation-generated water and heat are included. The model is calibrated using published data from a laboratory soil column test. Moreover, a series of parametric studies are carried out to investigate the influence of microbial oxidation-generated water and heat, initial water content on methane oxidation efficiency. Computed and measured results of gas concentration and methane oxidation rate are consistent. It is found that the coupling effects between water-gas-heat transfer and methane oxidation are significant. Ignoring microbial oxidation-generated water and heat can result in a significant difference in methane oxidation efficiency by 100%. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Characterization of methane oxidation in a simulated landfill cover system by comparing molecular and stable isotope mass balances.

    PubMed

    Schulte, Marcel; Jochmann, Maik A; Gehrke, Tobias; Thom, Andrea; Ricken, Tim; Denecke, Martin; Schmidt, Torsten C

    2017-08-12

    Biological methane oxidation may be regarded as a method of aftercare treatment for landfills to reduce climate relevant methane emissions. It is of social and economic interest to estimate the behavior of bacterial methane oxidation in aged landfill covers due to an adequate long-term treatment of the gas emissions. Different approaches assessing methane oxidation in laboratory column studies have been investigated by other authors recently. However, this work represents the first study in which three independent approaches, ((i) mass balance, (ii) stable isotope analysis, and (iii) stoichiometric balance of product (CO2) and reactant (CH4) by CO2/CH4-ratio) have been compared for the estimation of the biodegradation by a robust statistical validation on a rectangular, wide soil column. Additionally, an evaluation by thermal imaging as a potential technique for the localization of the active zone of bacterial methane oxidation has been addressed in connection with stable isotope analysis and CO2/CH4-ratios. Although landfills can be considered as open systems the results for stable isotope analysis based on a closed system correlated better with the mass balance than calculations based on an open system. CO2/CH4-ratios were also in good agreement with mass balance. In general, highest values for biodegradation were determined from mass balance, followed by CO2/CH4-ratio, and stable isotope analysis. The investigated topsoil proved to be very suitable as a potential cover layer by removing up to 99% of methane for CH4 loads of 35-65gm(-2)d(-1) that are typical in the aftercare phase of landfills. Finally, data from stable isotope analysis and the CO2/CH4-ratios were used to trace microbial activity within the reactor system. It was shown that methane consumption and temperature increase, as a cause of high microbial activity, correlated very well. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Spatial Variability of Soil Properties and Their Effect on Methane Generation, Oxidation, and Emission from Soils Covering Landfills

    NASA Astrophysics Data System (ADS)

    Imhoff, P. T.; Mei, C.; Yazdani, R.; Han, B.; Mostafid, M.

    2013-12-01

    Soils covering landfills mitigate gas emissions from degrading refuse, particularly emissions of methane, a potent greenhouse gas. To enhance the oxidative capacity of these soils, materials with high organic matter are proposed for landfill covers, e.g., compost and aged greenwaste. We report field tests of these materials in pilot-scale test cells. While moisture conditions and gas transport were initially uniform, after one year significant spatial variability of gas flow developed that was associated with spatially variable dry bulk density and volumetric water content. For a test cell with organic matter content of 38%, a single-domain porous medium model was adequate for describing water retention and continuum modeling was capable of describing spatially variable gas flow and methane oxidation. A second test cell with organic matter of 61% was best described as a dual-domain porous medium, and continuum modeling was inadequate for describing spatially variable gas flow. Here, the dual-domain medium resulted in significant subgrid scale variability in moisture conditions that affected gas transport and methane oxidation. The results from these field tests suggest that proposed one-dimensional models of gas transport and methane oxidation in landfill cover soils may be inadequate for soils composed of high organic matter that require dual-domain models for water retention.

  14. Methane recovery from animal manures: A current opportunities casebook

    SciTech Connect

    1995-08-01

    This Casebook examines some of the current opportunities for the recovery of methane from the anaerobic digestion of animal manures US livestock operations currently employ four types of anaerobic digester technology: Slurry, plug flow, complete mix, and covered lagoon. An introduction to the engineering economies of these technologies is provided, and possible end-use applications for the methane gas generated by the digestion process are discussed. The economic evaluations are based on engineering studies of digesters that generate electricity from the recovered methane. Regression models, which can be used to estimate digester cost and internal rate of return, are developed from the evaluations.

  15. Methane oxidation in a neutral landfill cover soil: Influence of moisture content, temperature, and nitrogen-turnover

    SciTech Connect

    Boeckx, P.; Van Cleemput, O.

    1996-01-01

    Well-managed, aerated cover soils can have a mitigating effect on methane emission from landfills. The influence of moisture content, soil temperature, and N on the methane uptake capacity of a neutral landfill cover soil was examined. A soil moisture content of 15% w/w gave the maximum CH{sub 4} oxidation rate (2.36 ng CH{sub 4}{sup -1}g{sup -1} soil). When wetter, CH{sub 4} consumption was slower (e.g., 1.6 ng CH{sub 4} h{sup -1} g {sup -1} at 30% w/w) because of a limited gas diffusion. At lower soil moisture, microbial activity was reduced and consequently the oxidation capacity decreased (e.g., 0.84 ng CH{sub 4} {sup -1} g{sup -1} at 5% w/w). Optimum temperature was between 25 and 30{degrees}C. The calculated activation energy of the CH{sub 4} oxidation was 56.5 kj K{sup -1} mol{sup -1}. After NH4{sub 4}{sup +} addition, a negative linear correlation was found between the methane oxidation rate and the nitrous oxide flux (R{sup 2} = 0.96 Y1 = 2.7 - 0.44 x Y2). Addition of NO{sub 3}{sup -} had no significant effect on CH{sub 4} oxidation. The effect of organic residue amendments depended on their C/N ratios. Crop residues with a high C/N ratio (wheat [Triticum sativum L.] and maize [Zea mays L.] straw) stimulated N-immobilization and did not affect the methane-oxidizing capacity. On the other hand, addition of crop residues with low C/N ratios (potato [Solanum tuberosum L.] and sugar beet [Beta vulgaris cv. Altissima] leaves) stimulated N-mineralization, resulting in a strong inhibition of the methane oxidation. 38 refs., 4 figs., 2 tabs.

  16. Use of a biologically active cover to enhance landfill methane oxidation

    NASA Astrophysics Data System (ADS)

    Stern, J. C.; Chanton, J.; Abichou, T.; Powelson, D.; Yuan, L.; Bogner, J.

    2005-12-01

    The emplacement of a biocover composed of a glass dispersion layer and a compost layer at the Tallahassee MSW Landfill significantly reduced methane emissions (by a factor of 10) and doubled the oxidation of methane compared to a non-treated control area of the landfill. The biocover became more effective than the control in oxidizing methane three months after its initial emplacement. Percent oxidation of methane was calculated using the carbon isotopic composition and concentration of methane emitted at the surface of the landfill. Over the one-year period of study, the difference in methane emission rate and methane oxidation percentage in the control and the biocover were statistically significant (p < 0.001). Following the initial three-month curing period, the mean oxidation for the biocover was 38%, and the mean oxidation for the control was 19%. Following the three month curing period 29 negative fluxes and 27 zero fluxes were observed in the biocover, while only 6 negative fluxes and 22 zero fluxes were onserved in the control area. Negative fluxes indicate uptake of atmospheric methane. If these zero and negative fluxes are assumed to represent 100% oxidation then the mean percent oxidation for the biocover and control areas increase to 56% and 39% respectively. Individual flux chambers showed a negative correlation between soil moisture and oxidation and a positive correlation between soil temperature and oxidation. Neither flux nor oxidation exhibited a distinct seasonality, perhaps due to relatively warm temperatures throughout the year or the effects of soil moisture buffering the effects of temperature.

  17. Sludge storage lagoon biogas recovery and use

    SciTech Connect

    Muller, D.; Norville, C. )

    1991-07-01

    The City of Memphis has two wastewater treatment plants. The SWTP employs two large anaerobic digestion sludge lagoons as part of the overall sludge treatment system. Although these lagoons are effective in concentrating and digesting sludge, they can generate offensive odors. The SWTP uses aerobic digesters to partially stabilize the sludge and help reduce objectionable odors before it enters the lagoons. The anaerobic digestion of sludge in the lagoons results in the dispersion of a large quantity of biogas into the atmosphere. The City realized that if the lagoons could be covered, the odor problem could be resolved, and at the same, time, biogas could be recovered and utilized as a source of energy. In 1987, the City commissioned ADI International to conduct a feasibility study to evaluate alternative methods of covering the lagoons and recovering and utilizing the biogas. The study recommended that the project be developed in two phases: (1) recovery of the biogas and (2) utilization of the biogas. Phase 1 consists of covering the two lagoons with an insulated membrane to control odor and temperature and collect the biogas. Phase 1 was found to be economically feasible and offered a unique opportunity for the City to save substantial operating costs at the treatment facility. The Memphis biogas recovery project is the only application in the world where a membrane cover has been used on a municipal wastewater sludge lagoon. It is also the largest lagoon cover system in the world.

  18. Effect of temperature and oxidation rate on carbon-isotope fractionation during methane oxidation by landfill cover materials.

    PubMed

    Chanton, Jeffrey P; Powelson, David K; Abichou, Tarek; Fields, Dana; Green, Roger

    2008-11-01

    The quantification of methane oxidation is one of the major uncertainties in estimating CH4 emissions from landfills. Stable isotope methods provide a useful field approach for the quantification of methane oxidation in landfill cover soils. The approach relies upon the difference between the isotopic composition of oxidized gas at the location of interest and anaerobic zone CH4 and knowledge of alpha(ox), a term that describes the isotopic fractionation of the methanotrophic bacteria in their discrimination against (13)CH4. Natural variability in alpha(0x) in different landfill soils and the effect of temperature and other environmental factors on this parameter are not well defined. Therefore, standard determinations of alpha(ox), batch incubations of landfill cover soils with CH4, were conducted to determine alpha(ox) under a variety of conditions. When these results were combined with those of previous landfill incubation studies, the average alpha(ox) at 25 degrees C was 1.022 +/- 0.0015. alpha(ox) decreased with increasing temperature (-0.00039 alpha(ox) degrees C(-1)) overthe temperature range of 3-35 degrees C. alpha(ox) was found to be higher when determined after CH4-free storage and declined following CH4 pretreatment. alpha(ox) declined nonlinearly with increasing methane oxidation rate, Vmax.

  19. Use of gas push-pull tests for the measurement of methane oxidation in different landfill cover soils.

    PubMed

    Streese-Kleeberg, Jan; Rachor, Ingke; Gebert, Julia; Stegmann, Rainer

    2011-05-01

    In order to optimise methane oxidation in landfill cover soils, it is important to be able to accurately quantify the amount of methane oxidised. This research considers the gas push-pull test (GPPT) as a possible method to quantify oxidation rates in situ. During a GPPT, a gas mixture consisting of one or more reactive gases (e.g., CH(4), O(2)) and one or more conservative tracers (e.g., argon), is injected into the soil. Following this, the mixture of injected gas and soil air is extracted from the same location and periodically sampled. The kinetic parameters for the biological oxidation taking place in the soil can be derived from the differences in the breakthrough curves. The original method of Urmann et al. (2005) was optimised for application in landfill cover soils and modified to reduce the analytical effort required. Optimised parameters included the flow rate during the injection phase and the duration of the experiment. 50 GPPTs have been conducted at different landfills in Germany during different seasons. Generally, methane oxidation rates ranged between 0 and 150 g m(soil air)(-3)h(-1). At one location, rates up to 440 g m(soil air)(-3)h(-1) were measured under particularly favourable conditions. The method is simple in operation and does not require expensive equipment besides standard laboratory gas chromatographs. Copyright © 2010 Elsevier Ltd. All rights reserved.

  20. Methane oxidation in compost-based landfill cover with vegetation during wet and dry conditions in the tropics.

    PubMed

    Tanthachoon, Nathiya; Chiemchaisri, Chart; Chiemchaisri, Wilai; Tudsri, Sayan; Kumar, Sunil

    2008-05-01

    The effect of compost and vegetation on methane (CH4) oxidation was investigated during wet and dry conditions in a tropical region. A laboratory-scale experiment was conducted to examine the performance of nonvegetated and vegetated landfill cover systems in terms of CH4 oxidation efficiency. Two types of landfill cover materials (compost and sandy loam) and two species of tropical grasses (Sporobolus virginicus and Panicum repens) were studied for their effect on the CH4 oxidation reaction. It was found that the use of compost as cover material could maintain a high methane oxidation rate (MOR) of 12 mol CH4/m3 x day over a 250-day period. Leachate application showed a positive effect on promoting methanotrophic activity and increasing MOR. A high MOR of 12 mol CH4/m3 x day was achieved when using compost cover with P. repens during wet and dry seasons when leachate irrigation was practiced. In dry conditions, a lower MOR of 8 mol CH4/m3 x day was observed for 80 days.

  1. Moxos' Lagoons

    NASA Astrophysics Data System (ADS)

    Belmonte, Juan Antonio; Barba, Josep F.

    There has been a long-standing debate on the anthropogenic origin of Moxos' lagoons. In the late 1990s, an analysis of the orientation of a comprehensive and statistically significant number of lagoons showed that only human action could explain the peculiarities of their geometry and especially their orientation according to a main axis aligned to an azimuth of 50° and its complementary angle. Besides, the absence of distinctive geographical marks in the horizon strongly suggested an astronomical justification for such peculiar pattern. Thus, the lagoons could have been deliberately orientated in agreement with certain stellar positions which may have marked special moments of the local climatic or economic cycle, a fact which might be confirmed in ethno-historic references.

  2. Effect of summer throughfall exclusion, summer drought, and winter snow cover on methane fluxes in a temperate forest soil

    USGS Publications Warehouse

    Borken, W.; Davidson, E.A.; Savage, K.; Sundquist, E.T.; Steudler, P.

    2006-01-01

    Soil moisture strongly controls the uptake of atmospheric methane by limiting the diffusion of methane into the soil, resulting in a negative correlation between soil moisture and methane uptake rates under most non-drought conditions. However, little is known about the effect of water stress on methane uptake in temperate forests during severe droughts. We simulated extreme summer droughts by exclusion of 168 mm (2001) and 344 mm (2002) throughfall using three translucent roofs in a mixed deciduous forest at the Harvard Forest, Massachusetts, USA. The treatment significantly increased CH4 uptake during the first weeks of throughfall exclusion in 2001 and during most of the 2002 treatment period. Low summertime CH4 uptake rates were found only briefly in both control and exclusion plots during a natural late summer drought, when water contents below 0.15 g cm-3 may have caused water stress of methanotrophs in the A horizon. Because these soils are well drained, the exclusion treatment had little effect on A horizon water content between wetting events, and the effect of water stress was smaller and more brief than was the overall treatment effect on methane diffusion. Methane consumption rates were highest in the A horizon and showed a parabolic relationship between gravimetric water content and CH4 consumption, with maximum rate at 0.23 g H2O g-1 soil. On average, about 74% of atmospheric CH4 was consumed in the top 4-5 cm of the mineral soil. By contrast, little or no CH4 consumption occurred in the O horizon. Snow cover significantly reduced the uptake rate from December to March. Removal of snow enhanced CH4 uptake by about 700-1000%, resulting in uptake rates similar to those measured during the growing season. Soil temperatures had little effect on CH4 uptake as long as the mineral soil was not frozen, indicating strong substrate limitation of methanotrophs throughout the year. Our results suggest that the extension of snow periods may affect the annual rate

  3. CH4/CO2 ratios indicate highly efficient methane oxidation by a pumice landfill cover-soil.

    PubMed

    Pratt, Chris; Walcroft, Adrian S; Deslippe, Julie; Tate, Kevin R

    2013-02-01

    Landfills that generate too little biogas for economic energy recovery can potentially offset methane (CH(4)) emissions through biological oxidation by methanotrophic bacteria in cover soils. This study reports on the CH(4) oxidation efficiency of a 10-year old landfill cap comprising a volcanic pumice soil. Surface CH(4) and CO(2) fluxes were measured using field chambers during three sampling intervals over winter and summer. Methane fluxes were temporally and spatially variable (-0.36 to 3044 mgCH(4)m(-2)h(-1)); but were at least 15 times lower than typical literature CH(4) fluxes reported for older landfills in 45 of the 46 chambers tested. Exposure of soil from this landfill cover to variable CH(4) fluxes in laboratory microcosms revealed a very strong correlation between CH(4) oxidation efficiency and CH(4)/CO(2) ratios, confirming the utility of this relationship for approximating CH(4) oxidation efficiency. CH(4)/CO(2) ratios were applied to gas concentrations from the surface flux chambers and indicated a mean CH(4) oxidation efficiency of 72%. To examine CH(4) oxidation with soil depth, we collected 10 soil depth profiles at random locations across the landfill. Seven profiles exhibited CH(4) removal rates of 70-100% at depths <60 cm, supporting the high oxidation rates observed in the chambers. Based on a conservative 70% CH(4) oxidation efficiency occurring at the site, this cover soil is clearly offsetting far greater CH(4) quantities than the 10% default value currently adopted by the IPCC. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Capacity for Methane Oxidation in Landfill Cover Soils Measured in Laboratory-Scale Soil Microcosms

    PubMed Central

    Kightley, D.; Nedwell, D. B.; Cooper, M.

    1995-01-01

    Laboratory-scale soil microcosms containing different soils were permeated with CH(inf4) for up to 6 months to investigate their capacity to develop a methanotrophic community. Methane emissions were monitored continuously until steady states were established. The porous, coarse sand soil developed the greatest methanotrophic capacity (10.4 mol of CH(inf4) (middot) m(sup-2) (middot) day(sup-1)), the greatest yet reported in the literature. Vertical profiles of O(inf2), CH(inf4), and methanotrophic potential in the soils were determined at steady state. Methane oxidation potentials were greatest where the vertical profiles of O(inf2) and CH(inf4) overlapped. A significant increase in the organic matter content of the soil, presumably derived from methanotroph biomass, occurred where CH(inf4) oxidation was greatest. Methane oxidation kinetics showed that a soil community with a low methanotrophic capacity (V(infmax) of 258 nmol (middot) g of soil(sup-1) (middot) h(sup-1)) but relatively high affinity (k(infapp) of 1.6 (mu)M) remained in N(inf2)-purged control microcosms, even after 6 months without CH(inf4). We attribute this to a facultative, possibly mixotrophic, methanotrophic microbial community. When purged with CH(inf4), a different methanotrophic community developed which had a lower affinity (k(infapp) of 31.7 (mu)M) for CH(inf4) but a greater capacity (V(infmax) of 998 nmol (middot) g of soil(sup-1) (middot) h(sup-1)) for CH(inf4) oxidation, reflecting the enrichment of an active high-capacity methanotrophic community. Compared with the unamended control soil, amendment of the coarse sand with sewage sludge enhanced CH(inf4) oxidation capacity by 26%; K(inf2)HPO(inf4) amendment had no significant effect, while amendment with NH(inf4)NO(inf3) reduced the CH(inf4) oxidation capacity by 64%. In vitro experiments suggested that NH(inf4)NO(inf3) additions (10 and 71 (mu)mol (middot) g of soil(sup-1)) inhibited CH(inf4) oxidation by a nonspecific ionic effect

  5. Improving the aeration of critical fine-grained landfill top cover material by vegetation to increase the microbial methane oxidation efficiency.

    PubMed

    Bohn, Sonja; Brunke, Paul; Gebert, Julia; Jager, Johannes

    2011-05-01

    The natural methane oxidation potential of methanotrophic bacteria in landfill top covers is a sustainable and inexpensive method to reduce methane emissions to the atmosphere. Basically, the activity of methanotrophic bacteria is limited by the availability of oxygen in the soil. A column study was carried out to determine whether and to what extent vegetation can improve soil aeration and maintain the methane oxidation process. Tested soils were clayey silt and mature compost. The first soil is critical in light of surface crusting due to vertical erosion of an integral part of fine-grained material, blocking pores required for the gas exchange. The second soil, mature compost, is known for its good methane oxidation characteristics, due to high air-filled porosity, favorable water retention capacity and high nutrient supply. The assortment of plants consisted of a grass mixture, Canadian goldenrod and a mixture of leguminous plants. The compost offered an excellent methane oxidation potential of 100% up to a CH(4)-input of 5.6l CH(4)m(-2)h(-1). Whereas the oxidation potential was strongly diminished in the bare control column filled with clayey silt even at low CH(4)-loads. By contrast the planted clayey silt showed an increased methane oxidation potential compared to the bare column. The spreading root system forms secondary macro-pores, and hence amplifies the air diffusivity and sustain the oxygen supply to the methanotrophic bacteria. Water is produced during methane oxidation, causing leachate. Vegetation reduces the leachate by evapotranspiration. Furthermore, leguminous plants support the enrichment of soil with nitrogen compounds and thus improving the methane oxidation process. In conclusion, vegetation is relevant for the increase of oxygen diffusion into the soil and subsequently enhances effective methane oxidation in landfill cover soils. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Field-scale tracking of active methane-oxidizing communities in a landfill cover soil reveals spatial and seasonal variability.

    PubMed

    Henneberger, Ruth; Chiri, Eleonora; Bodelier, Paul E L; Frenzel, Peter; Lüke, Claudia; Schroth, Martin H

    2015-05-01

    Aerobic methane-oxidizing bacteria (MOB) in soils mitigate methane (CH4 ) emissions. We assessed spatial and seasonal differences in active MOB communities in a landfill cover soil characterized by highly variable environmental conditions. Field-based measurements of CH4 oxidation activity and stable-isotope probing of polar lipid-derived fatty acids (PLFA-SIP) were complemented by microarray analysis of pmoA genes and transcripts, linking diversity and function at the field scale. In situ CH4 oxidation rates varied between sites and were generally one order of magnitude lower in winter compared with summer. Results from PLFA-SIP and pmoA transcripts were largely congruent, revealing distinct spatial and seasonal clustering. Overall, active MOB communities were highly diverse. Type Ia MOB, specifically Methylomonas and Methylobacter, were key drivers for CH4 oxidation, particularly at a high-activity site. Type II MOB were mainly active at a site showing substantial fluctuations in CH4 loading and soil moisture content. Notably, Upland Soil Cluster-gamma-related pmoA transcripts were also detected, indicating concurrent oxidation of atmospheric CH4 . Spatial separation was less distinct in winter, with Methylobacter and uncultured MOB mediating CH4 oxidation. We propose that high diversity of active MOB communities in this soil is promoted by high variability in environmental conditions, facilitating substantial removal of CH4 generated in the waste body. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Stimulation of methane oxidation potential and effects on vegetation growth by bottom ash addition in a landfill final evapotranspiration cover.

    PubMed

    Kim, Gil Won; Ho, Adrian; Kim, Pil Joo; Kim, Sang Yoon

    2016-09-01

    The landfilling of municipal solid waste is a significant source of atmospheric methane (CH4), contributing up to 20% of total anthropogenic CH4 emissions. The evapotranspiration (ET) cover system, an alternative final cover system in waste landfills, has been considered to be a promising way to mitigate CH4 emissions, as well as to prevent water infiltration using vegetation on landfill cover soils. In our previous studies, bottom ash from coal-fired power plants was selected among several industrial residues (blast furnace slag, bottom ash, construction waste, steel manufacture slag, stone powder sludge, and waste gypsum) as the best additive for ET cover systems, with the highest mechanical performance achieved for a 35% (wtwt(-1)) bottom ash content in soil. In this study, to evaluate the field applicability of bottom ash mixed soil as ET cover, four sets of lysimeters (height 1.2m×width 2m×length 6m) were constructed in 2007, and four different treatments were installed: (i) soil+bottom ash (35% wtwt(-1)) (SB); (ii) soil+compost (2% wtwt(-1), approximately corresponding to 40Mgha(-1) in arable field scale) (SC); (iii) soil+bottom ash+compost (SBC); and (iv) soil only as the control (S). The effects of bottom ash mixing in ET cover soil on CH4 oxidation potential and vegetation growth were evaluated in a pilot ET cover system in the 5th year after installation by pilot experiments using the treatments. Our results showed that soil properties were significantly improved by bottom ash mixing, resulting in higher plant growth. Bottom ash addition significantly increased the CH4 oxidation potential of the ET cover soil, mainly due to improved organic matter and available copper concentration, enhancing methanotrophic abundances in soil amended with bottom ash. Conclusively, bottom ash could be a good alternative as a soil additive in the ET cover system to improve vegetation growth and mitigate CH4 emission impact in the waste landfill system. Copyright © 2016

  8. Field-scale labelling and activity quantification of methane-oxidizing bacteria in a landfill-cover soil.

    PubMed

    Henneberger, Ruth; Chiri, Eleonora; Blees, Jan; Niemann, Helge; Lehmann, Moritz F; Schroth, Martin H

    2013-02-01

    Aerobic methane-oxidizing bacteria (MOB) play an important role in soils, mitigating emissions of the greenhouse gas methane (CH(4)) to the atmosphere. Here, we combined stable isotope probing on MOB-specific phospholipid fatty acids (PLFA-SIP) with field-based gas push-pull tests (GPPTs). This novel approach (SIP-GPPT) was tested in a landfill-cover soil at four locations with different MOB activity. Potential oxidation rates derived from regular- and SIP-GPPTs agreed well and ranged from 0.2 to 52.8 mmol CH(4) (L soil air)(-1) day(-1). PLFA profiles of soil extracts mainly contained C(14) to C(18) fatty acids (FAs), with a dominance of C(16) FAs. Uptake of (13) C into MOB biomass during SIP-GPPTs was clearly indicated by increased δ(13)C values (up to c. 1500‰) of MOB-characteristic FAs. In addition, (13)C incorporation increased with CH(4) oxidation rates. In general, FAs C(14:0) , C(16:1ω8), C(16:1ω7) and C(16:1ω6) (type I MOB) showed highest (13)C incorporation, while substantial (13)C incorporation into FAs C(18:1ω8) and C(18:1ω7) (type II MOB) was only observed at high-activity locations. Our findings demonstrate the applicability of the SIP-GPPT approach for in situ quantification of potential CH(4) oxidation rates and simultaneous labelling of active MOB, suggesting a dominance of type I MOB over type II MOB in the CH(4)-oxidizing community in this landfill-cover soil. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  9. Methane oxidation potential of boreal landfill cover materials: The governing factors and enhancement by nutrient manipulation.

    PubMed

    Maanoja, Susanna T; Rintala, Jukka A

    2015-12-01

    Methanotrophs inhabiting landfill covers are in a crucial role in mitigating CH4 emissions, but the characteristics of the cover material or ambient temperature do not always enable the maximal CH4 oxidation potential (MOP). This study aimed at identifying the factors governing MOPs of different materials used for constructing biocovers and other cover structures. We also tested whether the activity of methanotrophs could be enhanced at cold temperature (4 and 12°C) by improving the nutrient content (NO3(-), PO4(3-), trace elements) of the cover material. Compost samples from biocovers designed to support CH4 oxidation were exhibiting the highest MOPs (4.16 μmol CH4 g dw(-1) h(-1)), but also the soil samples collected from other cover structures were oxidising CH4 (0.41 μmol CH4 g dw(-1) h(-1)). The best predictors for the MOPs were the NO3(-) content and activity of heterotrophic bacteria at 72.8%, which were higher in the compost samples than in the soil samples. The depletion of NO3(-) from the landfill cover material limiting the activity of methanotrophs could not be confirmed by the nutrient manipulation assay at 4°C as the addition of nitrogen decreased the MOPs from 0.090 μmol CH4 g dw(-1) h(-1) to <0.085 μmol CH4 g dw(-1) h(-1). At 12°C, all nutrient additions reduced the MOPs. The inhibition was believed to result from high ionic concentration caused by nutrient addition. At 4°C, the addition of trace elements increased the MOPs (>0.096 μmol CH4 g dw(-1)h(-1)) suggesting that this was attributable to stimulation of the enzymatic activity of the psychrotolerant methanotrophs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Evaluation of simultaneous biodegradation of methane and toluene in landfill covers.

    PubMed

    Su, Yao; Zhang, Xuan; Wei, Xiao-Meng; Kong, Jiao-Yan; Xia, Fang-Fang; Li, Wei; He, Ruo

    2014-06-15

    The biodegradation of CH4 and toluene in landfill cover soil (LCS) and waste biocover soil (WBS) was investigated with a serial toluene concentration in the headspace of landfill cover microcosms in this study. Compared with the LCS sample, the higher CH4 oxidation activity and toluene-degrading capacity occurred in the WBS sample. The co-existence of toluene in landfill gas would positively or negatively affect CH4 oxidation, mainly depending on the toluene concentrations and exposure time. The nearly complete inhibition of toluene on CH4 oxidation was observed in the WBS sample at the toluene concentration of ∼ 80,000 mg m(-3), which was about 10 times higher than that in the LCS sample. The toluene degradation rates in both landfill covers fitted well with the Michaelis-Menten model. These findings showed that WBS was a good alternative landfill cover material to simultaneously mitigate emissions of CH4 and toluene from landfills to the atmosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Methane emissions from MSW landfill with sandy soil covers under leachate recirculation and subsurface irrigation

    NASA Astrophysics Data System (ADS)

    Zhang, Houhu; He, Pinjing; Shao, Liming

    CH 4 emissions and leachate disposal are recognized as the two major concerns in municipal solid waste (MSW) landfills. Recently, leachate recirculation was attempted to accelerate land-filled waste biodegradation and thus enhanced landfill gas generation. Leachate irrigation was also conducted for volume reduction effectively. Nevertheless, the impacts of leachate recirculation and irrigation on landfill CH 4 emissions have not been previously reported. A field investigation of landfill CH 4 emissions was conducted on selected sandy soil cover with leachate recirculation and subsurface irrigation based on whole year around measurement. The average CH 4 fluxes were 311±903, 207±516, and 565±1460 CH 4 m -2 h -1 from site A without leachate recirculation and subsurface irrigation, lift B2 with leachate subsurface irrigation, and lift B1 with both leachate recirculation and subsurface irrigation, respectively. Both gas recovery and cover soil oxidation minimized CH 4 emissions efficiently, while the later might be more pronounced when the location was more than 5 m away from gas recovery well. After covered by additional clay soil layer, CH 4 fluxes dropped by approximately 35 times in the following three seasons compared to the previous three seasons in lift B2. The diurnal peaks of CH 4 fluxes occurred mostly followed with air or soil temperature in the daytimes. The measured CH 4 fluxes were much lower than those of documented data from the landfills, indicating that the influences of leachate recirculation and subsurface irrigation on landfill CH 4 emissions might be minimized with the help of a well-designed sandy soil cover. Landfill cover composed of two soil layers (clay soil underneath and sandy soil above) is suggested as a low-cost and effective alternative to minimize CH 4 emissions.

  12. Spatial patterns of methane oxidation and methanotrophic diversity in landfill cover soils of southern China.

    PubMed

    Chi, Zi-Fang; Lu, Wen-Jing; Wang, Hong-Tao

    2015-04-01

    Aerobic CH4 oxidation is an important CH4 sink in landfills. To investigate the distribution and community diversity of methanotrophs and link with soil characteristics and operational parameters (e.g., concentrations of O2, CH4), cover soil samples were collected at different locations and depths from the Mengzi semi-aerobic landfill (SAL) in Yunnan Province of southern China. Specific PCR followed by denaturing gradient gel electrophoresis and realtime PCR were used to examine methanotrophs in the landfill cover soils. The results showed that different locations did harbor distinct methanotroph communities. Methanotrophs were more abundant in areas near the venting pipes because of the higher O2 concentrations. The depth of 20-25 cm, where the ratio of the CH4 to O2 was within the range from 1.3 to 8.6, was more conducive to the growth of CH4-oxidizing bacteria. Type II methanotrophs dominated in all samples compared with Type I methanotrophs, as evidenced by the high ratio of Type II to Type I methanotrophic copy numbers (from 1.76 to 11.60). The total copy numbers of methanotrophs detected were similar to other ecosystems, although the CH4 concentration was much higher in SAL cover soil. Methylobacter and Methylocystis were the most abundant Type I and Type II methanotrophs genera, respectively, in the Mengzi SAL. The results suggested that SALs could provide a special environment with both high concentrations of CH4 and O2 for methanotrophs, especially around the vertical venting pipes.

  13. Effects of biochar and wood pellets amendments added to landfill cover soil on microbial methane oxidation: A laboratory column study.

    PubMed

    Yargicoglu, Erin N; Reddy, Krishna R

    2017-05-15

    Alternate landfill covers designed to enhance microbial methane (CH4) oxidation and reduce the negative impacts of landfill gas emissions on global climate have recently been proposed and investigated. In this study, the use of biochar as a soil amendment is examined in order to assess the feasibility and effectiveness for enhanced CH4 removal in landfill covers when incorporated under high compaction conditions and relatively low soil moisture. Four different cover configurations were tested in large soil columns for ∼510 days and potential CH4 oxidation rates were determined following long-term incubation in small batch assays. Cover designs tested include: a thin biochar layer at 15-18 cm; 2% mixed soil-biochar layer at 20-40 cm; 2% mixed soil-uncharred wood pellets at 20-40 cm; and soil obtained from intermediate cover at an active landfill site. The placement of a thin biochar layer in the cover significantly impacted moisture distribution and infiltration, which in turn affected CH4 oxidation potential with depth. An increase in CH4 removal rates was observed among all columns over the 500 day incubation period, with steady-state CH4 removal efficiencies ranging from ∼60 to 90% in the final stages of incubation (inlet load ∼80 g CH4 m(-2) d(-1)). The thin biochar layer had the lowest average removal efficiency as a result of reduced moisture availability below the biochar layer. The addition of 2% biochar to soil yielded similar CH4 oxidation rates in terminal assays as the 2% uncharred wood pellet amendment. CH4 oxidation rates in terminal assays were positively correlated with soil moisture, which was affected by the materials' water holding capacity. The high water holding capacity of biochar led to higher oxidation rates within the thin biochar layer, supporting the initial hypothesis that biochar may confer more favorable physical conditions for methanotrophy. Ultimate performance was apparently affected by soil type and CH4 exposure history

  14. The geochemistry of methane in Lake Fryxell, an amictic, permanently ice-covered, antarctic lake

    USGS Publications Warehouse

    Smith, R.L.; Miller, L.G.; Howes, B.L.

    1993-01-01

    The abundance and distribution of dissolved CH4 were determined from 1987-1990 in Lake Fryxell, Antarctica, an amictic, permanently ice-covered lake in which solute movement is controlled by diffusion. CH4 concentrations were < 1 ??M in the upper oxic waters, but increased below the oxycline to 936 ??M at 18 m. Sediment CH4 was 1100 ??mol (1 sed)-1 in the 0-5 cm zone. Upward flux from the sediment was the source of the CH4, NH4 +, and DOC in the water column; CH4 was 27% of the DOC+CH4 carbon at 18 m. Incubations with surficial sediments indicated that H14CO3 - reduction was 0.4 ??mol (1 sed)-1 day-1 or 4?? the rate of acetate fermentation to CH4. There was no measurable CH4 production in the water column. However, depth profiles of CH4, NH4, and DIC normalized to bottom water concentrations demonstrated that a significant CH4 sink was evident in the anoxic, sulfate-containing zone of the water column (10-18 m). The ??13CH4 in this zone decreased from -72 % at 18 m to -76% at 12 m, indicating that the consumption mechanism did not result in an isotopic enrichment of 13CH4. In contrast, ??13CH4 increased to -55 % at 9 m due to aerobic oxidation, though this was a minor aspect of the CH4 cycle. The water column CH4 profile was modeled by coupling diffusive flux with a first order consumption term; the best-fit rate constant for anaerobic CH4 consumption was 0.012 yr-1. On a total carbon basis, CH4 consumption in the anoxic water column exerted a major effect on the flux of carbonaceous material from the underlying sediments and serves to exemplify the importance of CH4 to carbon cycling in Lake Fryxell. ?? 1993 Kluwer Academic Publishers.

  15. Sludge storage lagoon biogas recovery and use. Volume 2

    SciTech Connect

    Muller, D.; Norville, C.

    1991-07-01

    The City of Memphis has two wastewater treatment plants. The SWTP employs two large anaerobic digestion sludge lagoons as part of the overall sludge treatment system. Although these lagoons are effective in concentrating and digesting sludge, they can generate offensive odors. The SWTP uses aerobic digesters to partially stabilize the sludge and help reduce objectionable odors before it enters the lagoons. The anaerobic digestion of sludge in the lagoons results in the dispersion of a large quantity of biogas into the atmosphere. The City realized that if the lagoons could be covered, the odor problem could be resolved, and at the same, time, biogas could be recovered and utilized as a source of energy. In 1987, the City commissioned ADI International to conduct a feasibility study to evaluate alternative methods of covering the lagoons and recovering and utilizing the biogas. The study recommended that the project be developed in two phases: (1) recovery of the biogas and (2) utilization of the biogas. Phase 1 consists of covering the two lagoons with an insulated membrane to control odor and temperature and collect the biogas. Phase 1 was found to be economically feasible and offered a unique opportunity for the City to save substantial operating costs at the treatment facility. The Memphis biogas recovery project is the only application in the world where a membrane cover has been used on a municipal wastewater sludge lagoon. It is also the largest lagoon cover system in the world.

  16. Theoretical analysis of coupled effects of microbe and root architecture on methane oxidation in vegetated landfill covers.

    PubMed

    Feng, S; Leung, A K; Ng, C W W; Liu, H W

    2017-12-01

    Reduction of soil moisture by plant root-water uptake could improve soil aeration for microbial aerobic methane oxidation (MAMO) in a landfill cover, but excessive soil moisture removal could suppress microbial activity due to water shortage. Existing models ignore the coupled microbe-vegetation interaction. It is thus not known whether the presence of plants is beneficial or adverse to MAMO. This study proposes a newly-improved theoretical model that couples the effects of root-water uptake and microbial activity for capturing water-gas flow and MAMO in unsaturated soils. Parametric studies are conducted to investigate the effects of root characteristics and transpiration rate on MAMO efficiency. Uniform, parabolic, exponential and triangular root architectures are considered. Ignoring the effects of water shortage on microbe over-predicts the MAMO efficiency significantly, especially for plants with traits that give high root-water uptake ability (i.e., uniformly-rooted and long root length). The effects of plants on MAMO efficiency depends on the initial soil moisture strongly. If the soil is too dry (i.e., close to the permanent wilting point), plant-water uptake, with any root architecture considered, would reduce MAMO efficiency as further soil water removal by plants suppresses microbial activity. Plants with exponential or triangular root architectures could preserve 10% higher MAMO than the other two cases. These two architectures are more capable of minimizing the adverse effects of root-water uptake due to microbial water shortage. This implies that high-water-demand plants such as those with long root length and with uniform or parabolic root architectures require more frequent irrigation to prevent from excessive reduction of MAMO efficiency. Copyright © 2017. Published by Elsevier B.V.

  17. Changes of soil carbon dioxide, methane, and nitrous oxide fluxes in relation to land use/cover management.

    PubMed

    Kooch, Yahya; Moghimian, Negar; Bayranvand, Mohammad; Alberti, Giorgio

    2016-06-01

    Conversions of land use/cover are associated with changes in soil properties and biogeochemical cycling, with implications for carbon (C), nitrogen (N), and trace gas fluxes. In an attempt to provide a comprehensive evaluation of the significance of different land uses (Alnus subcordata plantation, Taxodium distichum plantation, agriculture, and deforested areas) on soil features and on the dynamics of greenhouse gas (GHG) fluxes at local scale, this study was carried out in Mazandaran province, northern Iran. Sixteen samples per land use, from the top 10 cm of soil, were taken, from which bulk density, texture, water content, pH, organic C, total N, microbial biomass of C and N, and earthworm density/biomass were determined. In addition, the seasonal changes in the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were monitored over a year. Our results indicated that the different land uses were different in terms of soil properties and GHG fluxes. Even though the amount of the GHG varied widely during the year, the highest CO2 and CH4 fluxes (0.32 mg CO2 m(-2) day(-1) and 0.11 mg CH4 m(-2) day(-1), respectively) were recorded in the deforested areas. N2O flux was higher in Alnus plantation (0.18 mg N2O m(-2) day(-1)) and deforested areas (0.17 mg N2O m(-2) day(-1)) than at agriculture site (0.05 mg N2O m(-2) day(-1)) and Taxodium plantation (0.03 mg N2O m(-2) day(-1)). This study demonstrated strong impacts of land use change on soil-atmosphere trace gas exchanges and provides useful observational constraints for top-down and bottom-up biogeochemistry models.

  18. Time-series measurements of methane (CH4) distribution during open water and ice-cover in lakes throughout the Mackenzie River Delta (Canada)

    NASA Astrophysics Data System (ADS)

    McIntosh, H.; Lapham, L.; Orcutt, B.; Wheat, C. G.; Lesack, L.; Bergstresser, M.; Dallimore, S. R.; MacLeod, R.; Cote, M.

    2016-12-01

    Arctic lakes are known to emit large amounts of methane to the atmosphere and their importance to the global methane (CH4) cycle has been recognized. It is well known CH4 builds up in Arctic lakes during ice-cover, but the amount of and when the CH4 is released to the atmosphere is not well known. Our preliminary results suggest the largest flux of CH4 from lakes to the atmosphere occurs slightly before complete ice-out; while others have shown the largest flux occurs when lakes overturn in the spring. During ice-out, CH4 can also be oxidized by methane oxidizing bacteria before it can efflux to the atmosphere from the surface water. In order to elucidate the processes contributing to Arctic lake CH4 emissions, continuous, long-term and large scale spatial sampling is required; however it is difficult to achieve in these remote locations. We address this problem using two sampling techniques. 1) We deployed osmotically powered pumps (OsmoSamplers), which were able to autonomously and continuously collect lake bottom water over the course of a year from multiple lakes in the Mackenzie River Delta. OsmoSamplers were placed in four lakes in the mid Delta near Inuvik, Northwest Territories, Canada, two lakes in the outer Delta, and two coastal lakes on Richard's Island in 2015. The dissolved CH4 concentration, stable isotope content of CH4 (δ13C-CH4), and dissolved sulfate concentrations in bottom water from these lakes will be presented to better understand methane dynamics under the ice and over time. 2) Along with the time-series data, we will also present data from discrete samples collected from 40 lakes in the mid Delta during key time periods, before and immediately after the spring ice-out. By determining the CH4 dynamics throughout the year we hope to improve predictions of how CH4 emissions may change in a warming Arctic environment.

  19. Partial oxidative conversion of methane to methanol through selective inhibition of methanol dehydrogenase in methanotrophic consortium from landfill cover soil.

    PubMed

    Han, Ji-Sun; Ahn, Chang-Min; Mahanty, Biswanath; Kim, Chang-Gyun

    2013-11-01

    Using a methanotrophic consortium (that includes Methylosinus sporium NCIMB 11126, Methylosinus trichosporium OB3b, and Methylococcus capsulatus Bath) isolated from a landfill site, the potential for partial oxidation of methane into methanol through selective inhibition of methanol dehydrogenase (MDH) over soluble methane monooxygenase (sMMO) with some selected MDH inhibitors at varied concentration range, was evaluated in batch serum bottle and bioreactor experiments. Our result suggests that MDH activity could effectively be inhibited either at 40 mM of phosphate, 100 mM of NaCl, 40 mM of NH4Cl or 50 μM of EDTA with conversion ratios (moles of CH3OH produced per mole CH4 consumed) of 58, 80, 80, and 43 %, respectively. The difference between extent of inhibition in MDH activity and sMMO activity was significantly correlated (n = 6, p < 0.05) with resultant methane to methanol conversion ratio. In bioreactor study with 100 mM of NaCl, a maximum specific methanol production rate of 9 μmol/mg h was detected. A further insight with qPCR analysis of MDH and sMMO coding genes revealed that the gene copy number continued to increase along with biomass during reactor operation irrespective of presence or absence of inhibitor, and differential inhibition among two enzymes was rather the key for methanol production.

  20. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: daily, intermediate, and final California cover soils.

    PubMed

    Bogner, Jean E; Spokas, Kurt A; Chanton, Jeffrey P

    2011-01-01

    Compared with natural ecosystems and managed agricultural systems, engineered landfills represent a highly managed soil system for which there has been no systematic quantification of emissions from coexisting daily, intermediate, and final cover materials. We quantified the seasonal variability of CH, CO, and NO emissions from fresh refuse (no cover) and daily, intermediate, and final cover materials at northern and southern California landfill sites with engineered gas extraction systems. Fresh refuse fluxes (g m d [± SD]) averaged CH 0.053 (± 0.03), CO 135 (± 117), and NO 0.063 (± 0.059). Average CH emissions across all cover types and wet/dry seasons ranged over more than four orders of magnitude (<0.01-100 g m d) with most cover types, including both final covers, averaging <0.1 g m d with 10 to 40% of surface areas characterized by negative fluxes (uptake of atmospheric CH). The northern California intermediate cover (50 cm) had the highest CH fluxes. For both the intermediate (50-100 cm) and final (>200 cm) cover materials, below which methanogenesis was well established, the variability in gaseous fluxes was attributable to cover thickness, texture, density, and seasonally variable soil moisture and temperature at suboptimal conditions for CH oxidation. Thin daily covers (30 cm local soil) and fresh refuse generally had the highest CO and NO fluxes, indicating rapid onset of aerobic and semi-aerobic processes in recently buried refuse, with rates similar to soil ecosystems and windrow composting of organic waste. This study has emphasized the need for more systematic field quantification of seasonal emissions from multiple types of engineered covers.

  1. Brazil: Duck Lagoon

    Atmospheric Science Data Center

    2013-04-18

    ... in the lagoon during spring and summer. Although the lowland tapir (Tapirus terrestris) is found in some parts of Rio Grande do Sul, the Baird's tapir (Tapirus bairdii), is not distributed within the image area (it is ...

  2. Lockport Sewage Lagoon.

    ERIC Educational Resources Information Center

    Perry, John

    1995-01-01

    Describes a student initiated stewardship project that resulted in the transformation of a sewage lagoon near the school into a place to study nature. Contains a list of 20 things that discourage a successful stewardship project. (LZ)

  3. Lockport Sewage Lagoon.

    ERIC Educational Resources Information Center

    Perry, John

    1995-01-01

    Describes a student initiated stewardship project that resulted in the transformation of a sewage lagoon near the school into a place to study nature. Contains a list of 20 things that discourage a successful stewardship project. (LZ)

  4. Comparative oceanography of coastal lagoons

    NASA Technical Reports Server (NTRS)

    Kjerfve, Bjorn

    1986-01-01

    The hypothesis that physical lagoon characteristics and variability depend on the channel connecting the lagoon to the adjacent coastal ocean is evaluated. The geographical, hydrological, and oceanographic characteristics of 10 lagoon systems are described and analyzed; these oceanographic features are utilized to classify the lagoon systems. Choked lagoons (Laguna Joyuda, Coorong, Lake St.Lucia, Gippsland Lakes, Lake Songkla/Thale Luang/Thale Noi, and Lagoa dos Patos) are prevalent on coasts with high wave energy and low tidal range; restricted lagoons (Lake Pontchartrain and Laguna de Terminos) are located on low/medium wave energy coasts with a low tidal range; and leaky lagoons (Mississippi Sound and Belize Lagoon/Chetumal Bay) are connected to the ocean by wide tidal passes that transmit oceanic effects into the lagoon with a minimum of resistance. The data support the hypothesis that the nature of the connecting channel controls system functions.

  5. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils

    USDA-ARS?s Scientific Manuscript database

    We quantified the seasonal variability of CH4, CO2, and N2O emissions from fresh refuse and daily, intermediate, and final cover materials at two California landfills. Fresh refuse fluxes (g m-2 d-1) averaged CH4 0.053[+/-0.03], CO2 135[+/-117], and N2O 0.063[+/-0.059]. Average CH4 emissions across ...

  6. Inhibition of microbial metabolism in anaerobic lagoons by selected sulfonamides, tetracyclines, lincomycin, and tylosin tartrate

    USGS Publications Warehouse

    Loftin, Keith A.; Henny, Cynthia; Adams, Craig D.; Surampali, Rao; Mormile, Melanie R.

    2005-01-01

    Antibiotics are used to maintain healthy livestock and to promote weight gain in concentrated animal feed operations. Antibiotics rarely are metabolized completely by livestock and, thus, are often present in livestock waste and in waste-treatment lagoons. The introduction of antibiotics into anaerobic lagoons commonly used for swine waste treatment has the potential for negative impacts on lagoon performance, which relies on a consortium of microbes ranging from fermentative microorganisms to methanogens. To address this concern, the effects of eight common veterinary antibiotics on anaerobic activity were studied. Anaerobic microcosms, prepared from freshly collected lagoon slurries, were amended with individual antibiotics at 10 mg/L for the initial screening study and at 1, 5, and 25 mg/L for the dose-response study. Monitored metabolic indicators included hydrogen, methane, and volatile fatty acid concentrations as well as chemical oxygen demand. The selected antibiotics significantly inhibited methane production relative to unamended controls, thus indicating that antibiotics at concentrations commonly found in swine lagoons can negatively impact anaerobic metabolism. Additionally, historical antibiotic usage seems to be a potential factor in affecting methane production. Specifically, less inhibition of methane production was noted in samples taken from the lagoon with a history of multiple-antibiotic use.

  7. Assessment of methane emission and oxidation at Air Hitam Landfill site cover soil in wet tropical climate.

    PubMed

    Abushammala, Mohammed F M; Basri, Noor Ezlin Ahmad; Elfithri, Rahmah

    2013-12-01

    Methane (CH₄) emissions and oxidation were measured at the Air Hitam sanitary landfill in Malaysia and were modeled using the Intergovernmental Panel on Climate Change waste model to estimate the CH₄ generation rate constant, k. The emissions were measured at several locations using a fabricated static flux chamber. A combination of gas concentrations in soil profiles and surface CH₄ and carbon dioxide (CO₂) emissions at four monitoring locations were used to estimate the CH₄ oxidation capacity. The temporal variations in CH₄ and CO₂ emissions were also investigated in this study. Geospatial means using point kriging and inverse distance weight (IDW), as well as arithmetic and geometric means, were used to estimate total CH₄ emissions. The point kriging, IDW, and arithmetic means were almost identical and were two times higher than the geometric mean. The CH₄ emission geospatial means estimated using the kriging and IDW methods were 30.81 and 30.49 gm(−2) day(−1), respectively. The total CH₄ emissions from the studied area were 53.8 kg day(−1). The mean of the CH₄ oxidation capacity was 27.5 %. The estimated value of k is 0.138 year(−1). Special consideration must be given to the CH₄ oxidation in the wet tropical climate for enhancing CH₄ emission reduction.

  8. Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget

    NASA Technical Reports Server (NTRS)

    Wahlen, Martin

    1994-01-01

    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.

  9. Odor control in lagoons.

    PubMed

    Zhang, X L; Yan, S; Tyagi, R D; Surampalli, R Y

    2013-07-30

    Lagoons are widely used in rural area for wastewater treatment; however, the odor problem has hampered its application. The root of odor emission from lagoons varies from one to another. The key of controlling the odor is to find out the cause and accordingly provide strategies. Various physical, chemical, and biological methods have been reported and applied for odor control. Physical technologies such as masking, capturing and sorption are often employed to mitigate the pressure from compliant while not to cut off the problem. Chemical technologies which act rapidly and efficiently in odor control, utilize chemicals to damage the odorant production root or convert odorant to odorless substances. Biological methods such as aeration, biocover and biofiltration control the odor by enhancing aerobic condition or developing methanogens in lagoon, and biologically decomposing the odorants. Comparing to physical and chemical methods, biological methods are more feasible. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Up with methane

    SciTech Connect

    Barlaz, M.A.; Milke, M.W.; Ham, R.K.

    1986-12-01

    Methane production from municipal refuse represents a rapidly developing source of energy which remains underutilized. Part of the problem is the small amount of methane which is typically collected relative to the refuse's methane generation potential. This study was undertaken to define the parameters which affect the onset of methane production and methane yields in sanitary landfills. Ultimately, we need to develop refuse disposal methods which enhance its methane production potential. Included in the study were tests of how introduction of old refuse, use of sterile cover soil, addition of acetate to refuse, and use of leachate, recycling and neutralization affect methane generation. A more thorough understanding of how the microbes present in refuse react to different variables is the first step in the development of techniques for stimulating methane production in sanitary landfills.

  11. Circulation patterns in a channel reef-lagoon system, Ouano lagoon, New Caledonia

    NASA Astrophysics Data System (ADS)

    Sous, Damien; Chevalier, Cristele; Devenon, Jean-Luc; Blanchot, Jean; Pagano, Marc

    2017-09-01

    This paper reports on two three-months field experiments carried out in the Ouano lagoon, New Caledonia. This channel-type lagoon, exposed to meso-tides, south pacific swells and trade winds, has been monitored thanks to a network of currents profilers to understand the dynamics of the lagoon waters. Four typical circulation patterns have been identified, covering all together more than 90% of the survey period. These patterns are mainly driven by the waves and wind features. In particular, obliquely incident waves or strong winds blowing over a sufficient period are able to reverse the typical circulation pattern. The analysis of the vertical structure of the currents through passages shows the regular presence of a nearly linear vertical shear within the water column.

  12. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure.

    PubMed

    Arikan, Osman A; Mulbry, Walter; Lansing, Stephanie

    2015-09-01

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion. In temperate climates, digesters require a considerable amount of additional heat energy to maintain temperatures at these levels. In this study, the effects of lower digestion temperatures (22 and 28°C), on the methane production from dairy digesters were evaluated and compared with 35°C using duplicate replicates of field-scale (FS) digesters with a 17-day hydraulic retention time. After acclimation, the FS digesters were operated for 12weeks using solids-separated manure at an organic loading rate (OLR) of 1.4kgVSm(-3)d(-1) and then for 8weeks using separated manure amended with manure solids at an OLR of 2.6kgVSm(-3)d(-1). Methane production values of the FS digesters at 22 and 28°C were about 70% and 87%, respectively, of the values from FS digesters at 35°C. The results suggest that anaerobic digesters treating dairy manure at 28°C were nearly as efficient as digesters operated at 35°C, with 70% of total methane achievable at 22°C. These results are relevant to small farms interested in anaerobic digestion for methane reduction without heat recovery from generators or for methane recovery from covered lagoon digesters.

  13. Benthic Primary Production Budget of a Caribbean Reef Lagoon (Puerto Morelos, Mexico)

    PubMed Central

    Naumann, Malik S.; Jantzen, Carin; Haas, Andreas F.; Iglesias-Prieto, Roberto; Wild, Christian

    2013-01-01

    High photosynthetic benthic primary production (P) represents a key ecosystem service provided by tropical coral reef systems. However, benthic P budgets of specific ecosystem compartments such as macrophyte-dominated reef lagoons are still scarce. To address this, we quantified individual and lagoon-wide net (Pn) and gross (Pg) primary production by all dominant functional groups of benthic primary producers in a typical macrophyte-dominated Caribbean reef lagoon near Puerto Morelos (Mexico) via measurement of O2 fluxes in incubation experiments. The photosynthetically active 3D lagoon surface area was quantified using conversion factors to allow extrapolation to lagoon-wide P budgets. Findings revealed that lagoon 2D benthic cover was primarily composed of sand-associated microphytobenthos (40%), seagrasses (29%) and macroalgae (27%), while seagrasses dominated the lagoon 3D surface area (84%). Individual Pg was highest for macroalgae and scleractinian corals (87 and 86 mmol O2 m−2 specimen area d−1, respectively), however seagrasses contributed highest (59%) to the lagoon-wide Pg. Macroalgae exhibited highest individual Pn rates, but seagrasses generated the largest fraction (51%) of lagoon-wide Pn. Individual R was highest for scleractinian corals and macroalgae, whereas seagrasses again provided the major lagoon-wide share (68%). These findings characterise the investigated lagoon as a net autotrophic coral reef ecosystem compartment revealing similar P compared to other macrophyte-dominated coastal environments such as seagrass meadows and macroalgae beds. Further, high lagoon-wide P (Pg: 488 and Pn: 181 mmol O2 m−2 lagoon area d−1) and overall Pg:R (1.6) indicate substantial benthic excess production within the Puerto Morelos reef lagoon and suggest the export of newly synthesised organic matter to surrounding ecosystems. PMID:24367570

  14. Benthic primary production budget of a Caribbean reef lagoon (Puerto Morelos, Mexico).

    PubMed

    Naumann, Malik S; Jantzen, Carin; Haas, Andreas F; Iglesias-Prieto, Roberto; Wild, Christian

    2013-01-01

    High photosynthetic benthic primary production (P) represents a key ecosystem service provided by tropical coral reef systems. However, benthic P budgets of specific ecosystem compartments such as macrophyte-dominated reef lagoons are still scarce. To address this, we quantified individual and lagoon-wide net (Pn) and gross (Pg) primary production by all dominant functional groups of benthic primary producers in a typical macrophyte-dominated Caribbean reef lagoon near Puerto Morelos (Mexico) via measurement of O₂ fluxes in incubation experiments. The photosynthetically active 3D lagoon surface area was quantified using conversion factors to allow extrapolation to lagoon-wide P budgets. Findings revealed that lagoon 2D benthic cover was primarily composed of sand-associated microphytobenthos (40%), seagrasses (29%) and macroalgae (27%), while seagrasses dominated the lagoon 3D surface area (84%). Individual Pg was highest for macroalgae and scleractinian corals (87 and 86 mmol O₂ m(-2) specimen area d(-1), respectively), however seagrasses contributed highest (59%) to the lagoon-wide Pg. Macroalgae exhibited highest individual Pn rates, but seagrasses generated the largest fraction (51%) of lagoon-wide Pn. Individual R was highest for scleractinian corals and macroalgae, whereas seagrasses again provided the major lagoon-wide share (68%). These findings characterise the investigated lagoon as a net autotrophic coral reef ecosystem compartment revealing similar P compared to other macrophyte-dominated coastal environments such as seagrass meadows and macroalgae beds. Further, high lagoon-wide P (Pg: 488 and Pn: 181 mmol O₂ m(-2) lagoon area d(-1)) and overall Pg:R (1.6) indicate substantial benthic excess production within the Puerto Morelos reef lagoon and suggest the export of newly synthesised organic matter to surrounding ecosystems.

  15. 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

    SciTech Connect

    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.

  16. Lagoon Restoration Project: Final report

    SciTech Connect

    1995-03-01

    This project is a multiyear effort focusing on energy flow in the Palace of Fine Arts lagoon just outside the Exploratorium in San Francisco. Phase 1 was a pilot study to determine the feasibility of improving biological energy flow through the small freshwater lagoon, using the expertise and resources of an environmental artist in collaboration with museum biologists and arts department staff. The primary outcome of Phase 1 is an experimental fountain exhibit inside the museum designed by public artist Laurie Lundquist with Exploratorium staff. This fountain, with signage, functions both as a model for natural aeration and filtration systems and as a focal point for museum visitors to learn about how biological processes cycle energy through aquatic systems. As part of the study of the lagoon`s health, volunteers continued biweekly bird consus from March through September, 1994. The goal was to find out whether the poor water quality of the lagoon is affecting the birds. Limited dredging was undertaken by the city Parks and Recreation Department. However, a more peermanent solution to the lagoon`s ecological problems would require an ambitious redesign of the lagoon.

  17. The tale of four lagoons

    USDA-ARS?s Scientific Manuscript database

    Anaerobic lagoons are a common management practice in the Carolinas for the treatment of swine wastewater. Although these lagoons were once thought to be relatively simple; their physical, chemical, and biological processes are actually very sophisticated. To get a better understanding of the microb...

  18. Methane production by anaerobic digestion of water hyacinth (Eichhornia crassipes)

    SciTech Connect

    Klass, D.L.; Ghosh, S.

    1980-01-01

    Water hyacinth under conventional high-rate digestion conditions exhibited higher methane yields and energy recovery efficiencies when grown in sewage-fed lagoons as compared to the corresponding values obtained with water hyacinth grown in a fresh-water pond. Mesophilic digestion provided the highest feed energy recovered in the product gas as methane while thermophilic digestion, when operated at sufficiently high loading rates and reduced detention times, gave the highest specific methane production rates. Methane yields, volatile solids reduction, and energy recovery as methane for the sewage-grown water hyacinth were in the same range as those observed for other biomass substrates when digested under similar conditions.

  19. An evaluation of the USEPA calculations of greenhouse gas emissions from anaerobic lagoons.

    PubMed

    Lory, John A; Massey, R E; Zulovich, J M

    2010-01-01

    On 10 Apr. 2009, USEPA proposed and on 30 Oct. 2009 USEPA finalized reporting thresholds for a wide range of human-derived sources of greenhouse gas (GHG) as a first step in establishing emission limits in the United States. The only on-farm source category that required monitoring under the proposed and final rule was methane (CH(4)) and nitrous oxide (NO(2)) emissions from manure storage facilities. Our objective was to assess, through a literature review, the methodology used by USEPA to estimate current CH(4) emissions from uncovered anaerobic lagoons and the proposed methodology for reporting those emissions under the proposed rule. A review of the performance of uncovered anaerobic lagoons indicates that they are more effective at degrading volatile solids (VS) than predicted using parameters provided by USEPA that had been developed for anaerobic digesters. We also documented errors in the USEPA- and International Panel on Climate Change-estimated methane conversion factors for uncovered anaerobic lagoons. We suggest estimating CH(4) emissions from anaerobic lagoons based on VS degraded in the lagoon and B' (m(3) CH(4) generated kg(-1) VS destroyed). Our estimate of CH(4) released from uncovered anaerobic lagoons indicated the regulatory operation size threshold could be at least 65% smaller than predicted by USEPA in the proposed rule. Our calculated estimate of CH(4) emissions was substantially greater than the few estimates of CH(4) loss based on direct measurements on uncovered anaerobic lagoons. More research is needed before it will be possible to provide definitive estimates of CH(4) loss from uncovered anaerobic lagoons.

  20. A mass balance model to estimate the rate of composting, methane oxidation and anaerobic digestion in soil covers and shallow waste layers.

    PubMed

    Rafiee, Reza; Obersky, Lizanne; Xie, Sihuang; Clarke, William P

    2017-05-01

    Although CH4 oxidation in landfill soil covers is widely studied, the extent of composting and CH4 oxidation in underlying waste layers has been speculated but not measured. The objective of this study was to develop and validate a mass balance model to estimate the simultaneous rates of anaerobic digestion (rAD), CH4 oxidation (rOX) and composting (rCOM) in environments where O2 penetration is variable and zones of aerobic and anaerobic activity are intermingled. The modelled domain could include, as an example, a soil cover and the underlying shallow waste to a nominated depth. The proposed model was demonstrated on a blend of biogas from three separate known sources of gas representing the three reaction processes: (i) a bottle of laboratory grade 50:50% CH4:CO2 gas representing anaerobic digestion biogas; (ii) an aerated 250mL bottle containing food waste that represented composting activity; and (iii) an aerated 250mL bottle containing non-degradable graphite granules inoculated with methanotrophs and incubated with CH4 and O2 to represent methanotrophic activity. CO2, CH4, O2 and the stable isotope (13)C-CO2 were chosen as the components for the mass balance model. The three reaction rates, r (=rAD, rOX, rCOM) were calculated as fitting parameters to the overdetermined set of 4mass balance equations with the net flux of these components from the bottles q (= [Formula: see text] , [Formula: see text] , [Formula: see text] and [Formula: see text] ) as inputs to the model. The coefficient of determination (r(2)) for observed versus modelled values of r were 1.00, 0.97, 0.98 when the stoichiometry of each reaction was based on gas yields measured in the individual bottles and q was calculated by summing yields from the three bottles. r(2) deteriorated to 0.95, 0.96, 0.87 when using an average stoichiometry from 11 incubations of each of the composting and methane oxidation processes. The significant deterioration in the estimation of rCOM showed that this output

  1. Circulation in Enewetak Atoll lagoon

    SciTech Connect

    Atkinson, M.; Smith, S.V.; Stroup, E.D.

    1981-11-01

    Currents at Enewetak Atoll, Marshall Islands, were measured on the reef margins, in the channels, and in the lagoon. Lagoon circulation is dominated by wind-driven downwind surface flow and an upwind middepth return flow. This wind-driven flow has the characteristics of an Ekman spiral in an enclosed sea. Lagoon flushing is accomplished primarily by surf-driven water input over the windward (eastern) reefs and southerly drift out the South Channel. Mean water residence time is 1 month, while water entering the northern portion of the atoll takes about 4 months to exit.

  2. The basics of coalbed methane

    SciTech Connect

    2006-12-15

    The report is an overview of coalbed methane (CBM), also known as coal seam gas. It provides an overview of what coalbed methane is and the current status of global coalbed methane exploration and production. Topics covered in the report include: An analysis of the natural gas industry, including current and future production, consumption, and reserves; A detailed description of coalbed methane, its characteristics, and future potential; An analysis of the key business factors that are driving the increased interest in coalbed methane; An analysis of the barriers that are hindering the development of coalbed methane; An overview of the technologies used for coalbed methane production and water treatment; and Profiles of key coalbed methane producing countries. 25 figs., 5 tabs., 1 app.

  3. Mosquito Lagoon environmental resources inventory

    NASA Technical Reports Server (NTRS)

    Provancha, Jane A.; Hall, Carlton R.; Oddy, Donna M.

    1992-01-01

    This document provides a synopsis of biotic and abiotic data collected in the Mosquito Lagoon area in relation to water quality. A holistic ecological approach was used in this review to allow for summaries of climate, land use, vegetation, geohydrology, water quality, fishes, sea turtles, wading birds, marine mammals, invertebrates, shellfish, and mosquito control. The document includes a bibliographic database list of 157 citations that have references to the Mosquito Lagoon, many of which were utilized in development of the text.

  4. Assessment of the environmental quality of French continental Mediterranean lagoons with oyster embryo bioassay.

    PubMed

    Galgani, F; Senia, J; Guillou, J L; Laugier, T; Munaron, D; Andral, B; Guillaume, B; Coulet, E; Boissery, P; Brun, L; Bertrandy, M C

    2009-10-01

    In order to better understand environmental disturbances in the French coastal Mediterranean lagoons, we used an ecotoxicological approach based on the measurement of the toxicity of the sediments using oyster embryo bioassay that provides a basis for assessing the effects on the fauna of contaminants adsorbed on the sedimentary particles. The study covers all of the main lagoons of the French Mediterranean coasts of Languedoc Roussillon, Camargue, and Provence (Berre and Bolmon lagoons), where 188 stations were sampled. The toxicity tests provide evidence of variable levels of toxicity in sediments. Contaminated lagoons such as La peyrade, Le canet, and Ingrill and locally affected lagoons such as Bages-Sigean, Vaccares, Bolmon, and Berre have sampling stations with 100% of larval abnormalities during 24-h development. In all of the lagoons, the toxicity was mainly located close to local harbors and rivers. Salses Leucate (Languedoc roussillon) lagoon was found very clean, with no important toxicity. The results are discussed in terms of environmental disturbances of the coastal lagoons and with regard to the long-term monitoring of the impact of contaminants on the coastal environment.

  5. Effect of nutrient and selective inhibitor amendments on methane oxidation, nitrous oxide production, and key gene presence and expression in landfill cover soils: characterization of the role of methanotrophs, nitrifiers, and denitrifiers.

    PubMed

    Lee, Sung-Woo; Im, Jeongdae; Dispirito, Alan A; Bodrossy, Levente; Barcelona, Michael J; Semrau, Jeremy D

    2009-11-01

    Methane and nitrous oxide are both potent greenhouse gasses, with global warming potentials approximately 25 and 298 times that of carbon dioxide. A matrix of soil microcosms was constructed with landfill cover soils collected from the King Highway Landfill in Kalamazoo, Michigan and exposed to geochemical parameters known to affect methane consumption by methanotrophs while also examining their impact on biogenic nitrous oxide production. It was found that relatively dry soils (5% moisture content) along with 15 mg NH (4) (+) (kg soil)(-1) and 0.1 mg phenylacetylene(kg soil)(-1) provided the greatest stimulation of methane oxidation while minimizing nitrous oxide production. Microarray analyses of pmoA showed that the methanotrophic community structure was dominated by Type II organisms, but Type I genera were more evident with the addition of ammonia. When phenylacetylene was added in conjunction with ammonia, the methanotrophic community structure was more similar to that observed in the presence of no amendments. PCR analyses showed the presence of amoA from both ammonia-oxidizing bacteria and archaea, and that the presence of key genes associated with these cells was reduced with the addition of phenylacetylene. Messenger RNA analyses found transcripts of pmoA, but not of mmoX, nirK, norB, or amoA from either ammonia-oxidizing bacteria or archaea. Pure culture analyses showed that methanotrophs could produce significant amounts of nitrous oxide, particularly when expressing the particulate methane monooxygenase (pMMO). Collectively, these data suggest that methanotrophs expressing pMMO played a role in nitrous oxide production in these microcosms.

  6. Surface Water Quality Survey of Northern Indian River Lagoon from Sebastian Inlet to Mosquito Lagoon

    NASA Astrophysics Data System (ADS)

    Weaver, R. J.; Webb, B. M.

    2012-12-01

    Following news of an emerging brown tide algal bloom in the northern Indian River Lagoon (IRL), researchers sought to gain insight into the surface water quality in the IRL, as well as the extent of the algae coverage. A Portable SeaKeeper from YSI, mounted to a personal watercraft-based coastal profiling system, autonomously collected and analyzed the surface water. The system operates by recording sample data every 12 seconds while continuously underway at speeds up to and greater than 50 km/hr. The researchers covered a transect that started at Sebastian Inlet and followed a zig-zag path extending up through the Haulover Canal and into the Mosquito Lagoon. The survey path covered 166.7 km, and collected 2248 samples. Along the way stops were made at water quality stations used by the Saint John's River Water Management District, so that the data collected can be incorporated into ongoing monitoring efforts. The system analyzed the surface water for dissolved oxygen, pH, chlorophyll-a, salinity, temperature, turbidity, refined fuels, and CDOM. In the two days following the lagoon survey, the inlets at Port Canaveral and Sebastian were also surveyed for tidal currents and hydrography. The IRL transect survey data recorded evidence of the southern extent of the algae bloom in both chlorophyll-a and pH levels. Visual evidence of the bloom was striking as the water in the northern IRL turned a milk chocolaty brown color. Chlorophyll-a levels in the two inlets suggested bloom activity at these locations; however this bloom was different. This oceanic bloom was a result of a persistent upwelling event along the East Florida shelf, and the color was a paler green-yellow. The near-synoptic nature of the comprehensive lagoon survey, conducted in just over 7 hours, allows researchers to obtain a better understanding of water quality in coastal lagoons. Elevated levels of salinity, temperature, and refined fuels in the northern IRL indicate a low exchange rate and absence

  7. Anthropogenic methane ebullition and continuous flux measurement

    NASA Astrophysics Data System (ADS)

    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.

  8. Santa Margarita Lagoon Water Quality Monitoring Data

    DTIC Science & Technology

    2012-08-01

    boundary of the lagoon is defined by the easternmost extent of maximum tidal influence, roughly 1.5 miles upstream. The Santa Margarita River feeding...occurring in the lagoon . The data describe a lagoon that was strongly dominated by its connection with tidal flow from the ocean. Daily fluctuations in water...decreasing freshwater flow, summertime heating, longer daylight hours, and a reduction in tidal flow as a result of natural berm building at the lagoon

  9. 33 CFR 117.600 - Lagoon Pond.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Lagoon Pond. 117.600 Section 117.600 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.600 Lagoon Pond. The draw of the Lagoon Pond...

  10. 33 CFR 117.600 - Lagoon Pond.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Lagoon Pond. 117.600 Section 117.600 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.600 Lagoon Pond. The draw of the Lagoon Pond...

  11. 33 CFR 117.600 - Lagoon Pond.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Lagoon Pond. 117.600 Section 117.600 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.600 Lagoon Pond. The draw of the Lagoon Pond...

  12. 33 CFR 117.600 - Lagoon Pond.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Lagoon Pond. 117.600 Section 117.600 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.600 Lagoon Pond. The draw of the Lagoon Pond...

  13. 33 CFR 117.600 - Lagoon Pond.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Lagoon Pond. 117.600 Section 117.600 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.600 Lagoon Pond. The draw of the Lagoon Pond...

  14. Metagenomes of Mediterranean Coastal Lagoons

    PubMed Central

    Ghai, Rohit; Hernandez, Claudia Mella; Picazo, Antonio; Mizuno, Carolina Megumi; Ininbergs, Karolina; Díez, Beatriz; Valas, Ruben; DuPont, Christopher L.; McMahon, Katherine D.; Camacho, Antonio; Rodriguez-Valera, Francisco

    2012-01-01

    Coastal lagoons, both hypersaline and freshwater, are common, but still understudied ecosystems. We describe, for the first time, using high throughput sequencing, the extant microbiota of two large and representative Mediterranean coastal lagoons, the hypersaline Mar Menor, and the freshwater Albufera de Valencia, both located on the south eastern coast of Spain. We show there are considerable differences in the microbiota of both lagoons, in comparison to other marine and freshwater habitats. Importantly, a novel uncultured sulfur oxidizing Alphaproteobacteria was found to dominate bacterioplankton in the hypersaline Mar Menor. Also, in the latter prokaryotic cyanobacteria were almost exclusively comprised by Synechococcus and no Prochlorococcus was found. Remarkably, the microbial community in the freshwaters of the hypertrophic Albufera was completely in contrast to known freshwater systems, in that there was a near absence of well known and cosmopolitan groups of ultramicrobacteria namely Low GC Actinobacteria and the LD12 lineage of Alphaproteobacteria. PMID:22778901

  15. Metagenomes of Mediterranean coastal lagoons.

    PubMed

    Ghai, Rohit; Hernandez, Claudia Mella; Picazo, Antonio; Mizuno, Carolina Megumi; Ininbergs, Karolina; Díez, Beatriz; Valas, Ruben; DuPont, Christopher L; McMahon, Katherine D; Camacho, Antonio; Rodriguez-Valera, Francisco

    2012-01-01

    Coastal lagoons, both hypersaline and freshwater, are common, but still understudied ecosystems. We describe, for the first time, using high throughput sequencing, the extant microbiota of two large and representative Mediterranean coastal lagoons, the hypersaline Mar Menor, and the freshwater Albufera de Valencia, both located on the south eastern coast of Spain. We show there are considerable differences in the microbiota of both lagoons, in comparison to other marine and freshwater habitats. Importantly, a novel uncultured sulfur oxidizing Alphaproteobacteria was found to dominate bacterioplankton in the hypersaline Mar Menor. Also, in the latter prokaryotic cyanobacteria were almost exclusively comprised by Synechococcus and no Prochlorococcus was found. Remarkably, the microbial community in the freshwaters of the hypertrophic Albufera was completely in contrast to known freshwater systems, in that there was a near absence of well known and cosmopolitan groups of ultramicrobacteria namely Low GC Actinobacteria and the LD12 lineage of Alphaproteobacteria.

  16. PLANE-INTEGRATED OPEN-PATH FOURIER TRANSFORM INFRARED SPECTROMETRY METHODOLOGY FOR ANAEROBIC SWINE LAGOON EMISSION MEASUREMENTS

    EPA Science Inventory

    Emissions of ammonia and methane from an anaerobic lagoon at a swine animal feeding operation were evaluated five times over a period of two years. The plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) methodology was used to transect the plume at ...

  17. Neural network analysis on the effect of heat fluxes on greenhouse gas emissions from anaerobic swine waste treatment lagoon

    USDA-ARS?s Scientific Manuscript database

    In this study, we examined the various meteorological factors (i.e., air temperatures, solar radiation, and heat fluxes) that potentially affect greenhouse gas (GHG) emissions from swine waste lagoon. GHG concentrations (methane, carbon dioxide, and nitrous oxide) were monitored using a photoacous...

  18. PLANE-INTEGRATED OPEN-PATH FOURIER TRANSFORM INFRARED SPECTROMETRY METHODOLOGY FOR ANAEROBIC SWINE LAGOON EMISSION MEASUREMENTS

    EPA Science Inventory

    Emissions of ammonia and methane from an anaerobic lagoon at a swine animal feeding operation were evaluated five times over a period of two years. The plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) methodology was used to transect the plume at ...

  19. Distribution and stability of eelgrass beds at Izembek Lagoon, Alaska

    USGS Publications Warehouse

    Ward, David H.; Markon, Carl J.; Douglas, David C.

    1997-01-01

    Spatial change in eelgrass meadows, Zostera marina L., was assessed between 1978 and 1987 and between 1987 and 1995 at Izembek Lagoon, Alaska. Change in total extent was evaluated through a map to map comparison of data interpreted from a 1978 Landsat multi-spectral scanner image and 1987 black and white aerial photographs. A ground survey in 1995 was used to assess spatial change from 1987. Eelgrass beds were the predominant vegetation type in the lagoon, comprising 44-47% (15000-16000 ha) of the total area in 1978 and 1987. Izembek Lagoon contains the largest bed of seagrass along the Pacific Coast of North America and largest known single stand of eelgrass in the world. There was a high degree of overlap in the spatial distribution of eelgrass among years of change detection. The overall net change was a 6% gain between, 1978 and 1987 and a <1% gain between 1987 and 1995. The lack of significant change in eelgrass cover suggests that eelgrass meadows in Izembek Lagoon have been stable during the 17-year period of our study.

  20. Comparative study of wastewater lagoon with and without water hyacinth

    SciTech Connect

    McDonald, R.C.; Wolverton, B.C.

    1980-01-01

    A facultative sewage lagoon completely covered with water hyacinths had significant improvement in effluent quality. BOD 5 and total suspended solids (TSS) were 23 and b mg/L respectively. Without water hyacinths, the effluent BOD5 and TSS were 52 and 77 mg/L, respectively. The effluent total organic C concentration was reduced from 72 to 40 mg/L with water hyacinth coverage.

  1. Metals in some lagoons of Mexico.

    PubMed

    Vazquez, F G; Sharma, V K; Alexander, V H; Frausto, C A

    1995-02-01

    The concentrations of metals, Cd, Cu, Fe, Mn, Ni, Pb, and Zn were determined in some lagoons to establish the level of metal pollution. The lagoons studied were Alvarado lagoon, Veracruz; San Andres lagoon, Tamaulipas; and Terminos lagoon, Campeche. The concentrations were determined in water, oyster (Crassostrea virginica), and sediments. Metals were accumulated in either oysters or sediments. Cu and Zn were higher in oysters and Fe and Mn were higher in sediments. The results in water samples were compared with the limit established by the Secretaria de Ecologia and Desarrollo Urbano Report and briefly discussed.

  2. Metals in some lagoons of Mexico.

    PubMed Central

    Vazquez, F G; Sharma, V K; Alexander, V H; Frausto, C A

    1995-01-01

    The concentrations of metals, Cd, Cu, Fe, Mn, Ni, Pb, and Zn were determined in some lagoons to establish the level of metal pollution. The lagoons studied were Alvarado lagoon, Veracruz; San Andres lagoon, Tamaulipas; and Terminos lagoon, Campeche. The concentrations were determined in water, oyster (Crassostrea virginica), and sediments. Metals were accumulated in either oysters or sediments. Cu and Zn were higher in oysters and Fe and Mn were higher in sediments. The results in water samples were compared with the limit established by the Secretaria de Ecologia and Desarrollo Urbano Report and briefly discussed. PMID:7621796

  3. Lagoon microbialites on Isla Angel de la Guarda and associated peninsular shores, Gulf of California (Mexico)

    NASA Astrophysics Data System (ADS)

    Johnson, Markes E.; Ledesma-Vázquez, Jorge; Backus, David H.; González, Maria R.

    2012-07-01

    Examples of two closed lagoons with extensive growth of Recent microbialites showing variable surface morphology and internal structure are found on Isla Angel de la Guarda in the Gulf of California. Comparable lagoonal microbialites also occur ashore from Ensenada El Quemado on the adjacent peninsular mainland of Baja California. The perimeters of all three lagoons feature crusted structures indicative of thrombolites with a knobby surface morphology 2 cm to 3 cm in relief and internal clotting without any sign of laminations. Outward from this zone, thrombolitic construction thins to merge with a white calcified crust below which a soft substratum of dark organic material 4 cm to 6 cm in thickness is concealed. The substratum is laminated and heavily mucilaginous, as observed along the edges of extensive shrinkage cracks in the overlying crust. The thrombolitic crust is anchored to the shore, while the thinner crust and associated stromatolitic mats float on the surface of the lagoons. Laboratory cultures of the dark organic material yielded the solitary cyanobacterium Chroococcidiopsis as the predominant taxon interspersed with filamentous forms. In decreasing order of abundance, other morphotypes present include Phormidium, Oscillatoria, Geitlerinema, Chroococus, and probably Spirulina. The larger of the two island lagoons follows an east-west azimuth and covers 0.225 km2, while the smaller lagoon has a roughly north-south axis and covers only 0.023 km2. The salinity of water in the smaller lagoon was measured as148 ppt. Pliocene strata along the edge of the smaller modern lagoon include siltstone bearing calcified platelets suggestive of a microbial origin. Dry lagoons abandoned during the later Quaternary occur inland at higher elevations on the island, but retain no fossils except for sporadic white crusts cemented on cobbles around distinct margins. Raised Quaternary lagoons parallel to the big lagoon on Isla Angel de la Guarda are partly obscured by flood

  4. Genesis, distribution, and dynamics of lagoon marl extrusions along the Curonian Spit, southeast Baltic Coast

    NASA Astrophysics Data System (ADS)

    Sergeev, Alexander; Zhamoida, Vladimir; Ryabchuk, Daria; Buynevich, Ilya; Sivkov, Vadim; Dorokhov, Dmitry; Bitinas, Albertas; Pupienis, Donatas

    2016-04-01

    The unique geological process of extrusion of lagoon marl from beneath the massive migrating sand dunes is characteristic for large segments of the Curonian Spit - a ~100-km-long sandy barrier that separates the Curonian Lagoon from the Baltic Sea. The exposures of a composite set of Holocene organic sediments such as gyttja, clayey gyttja, and gyttja clay, commonly referred to as "lagoon marl", are common along the northern half of the lagoon coast of the spit. These outcrops of lagoon marl rise up to 3-4 m above the lagoon level and were formed by extrusion from their 7-8 m in situ depth beneath the present regional water table. New detailed investigations of the Baltic Sea bottom along the southern half of the Curonian Spit using side-scan sonar, multibeam echosounder, seismic imaging, sediment sampling, and video observations allowed identification and mapping of a unique underwater landscape formed by extensive outcrops of laminated and folded lagoon marl at water depths of 5-15 m. The combined onshore-offshore database indicates that the relict lagoon marl was deformed, compacted, and dehydrated by a massive dune-covered coastal barrier migrating landward (retrograding) over these sediments during the Litorina Sea transgression in a processes termed "dune tectonics". Spatial analysis of structures of the relict sediments traced in offshore geophysical data help constrain the rates of the southeastly migration of the dune massif. A conceptual dynamic model is presented to explain the present occurrence of marl exposures above the regional water table, as well as the occurrence of relict lagoon marl extrusions (diapirs) on the underwater marine slope of the Curonian Spit. This research was funded by a RFBR project 13-05-90711 and RSF project 14-37-00047 «Geoenvironmental conditions of marine management of natural recourses of the Russian sector of South-Eastern Baltic».

  5. Accuracy of vertical radial plume mapping technique in measuring lagoon gas emissions.

    PubMed

    Viguria, Maialen; Ro, Kyoung S; Stone, Kenneth C; Johnson, Melvin H

    2015-04-01

    Recently, the U.S. Environmental Protection Agency (EPA) posted a ground-based optical remote sensing method on its Web site called Other Test Method (OTM) 10 for measuring fugitive gas emission flux from area sources such as closed landfills. The OTM 10 utilizes the vertical radial plume mapping (VRPM) technique to calculate fugitive gas emission mass rates based on measured wind speed profiles and path-integrated gas concentrations (PICs). This study evaluates the accuracy of the VRPM technique in measuring gas emission from animal waste treatment lagoons. A field trial was designed to evaluate the accuracy of the VRPM technique. Control releases of methane (CH4) were made from a 45 m×45 m floating perforated pipe network located on an irrigation pond that resembled typical treatment lagoon environments. The accuracy of the VRPM technique was expressed by the ratio of the calculated emission rates (QVRPM) to actual emission rates (Q). Under an ideal condition of having mean wind directions mostly normal to a downwind vertical plane, the average VRPM accuracy was 0.77±0.32. However, when mean wind direction was mostly not normal to the downwind vertical plane, the emission plume was not adequately captured resulting in lower accuracies. The accuracies of these nonideal wind conditions could be significantly improved if we relaxed the VRPM wind direction criteria and combined the emission rates determined from two adjacent downwind vertical planes surrounding the lagoon. With this modification, the VRPM accuracy improved to 0.97±0.44, whereas the number of valid data sets also increased from 113 to 186. The need for developing accurate and feasible measuring techniques for fugitive gas emission from animal waste lagoons is vital for livestock gas inventories and implementation of mitigation strategies. This field lagoon gas emission study demonstrated that the EPA's vertical radial plume mapping (VRPM) technique can be used to accurately measure lagoon gas

  6. Aspects of fish conservation in the upper Patos Lagoon basin.

    PubMed

    Fontoura, N F; Vieira, J P; Becker, F G; Rodrigues, L R; Malabarba, L R; Schulz, U H; Möller, O O; Garcia, A M; Vilella, F S

    2016-07-01

    The Patos Lagoon basin is a large (201 626 km(2) ) and complex drainage system in southern Brazil. The lagoon is 250 km long and 60 km wide, covering an area of 10 360 km(2) . The exchange of water with the Atlantic Ocean occurs through a 0·8 km wide and 15 m deep inlet, fixed by 4 km long jetties, at the southernmost part of the Patos Lagoon. The estuarine area is restricted to its southern portion (10%), although the upper limit of saline waters migrates seasonally and year to year, influenced by the wind regime and river discharge. The known number of recorded limnetic fish species is 200, but this number is expected to increase. A higher endemism is observed in fish species occurring in upper tributaries. The basin suffers from the direct impact of almost 7 million inhabitants, concentrated in small to large cities, most with untreated domestic effluents. There are at least 16 non-native species recorded in natural habitats of the Patos Lagoon basin, about half of these being from other South American river basins. Concerning the fishery, although sport and commercial fisheries are widespread throughout the Patos Lagoon basin, the lagoon itself and the estuarine area are the main fishing areas. Landing statistics are not available on a regular basis or for the whole basin. The fishery in the northern Patos Lagoon captures 31 different species, nine of which are responsible for most of the commercial catches, but only three species are actually sustaining the artisanal fishery: the viola Loricariichthys anus: 455 kg per 10 000 m(2) gillnet per day, the mullet Mugil liza: 123 kg per 10 000 m(2) gillnet per day and the marine catfish Genidens barbus: 50 kg per 10 000 m(2) gillnet per day. A decline of the fish stocks can be attributed to inadequate fishery surveillance, which leads to overfishing and mortality of juveniles, or to decreasing water quality because of urban and industrial activities and power production. Global climatic changes also represent a

  7. Real-time monitoring of methane oxidation in a simulated landfill cover soil and MiSeq pyrosequencing analysis of the related bacterial community structure.

    PubMed

    Xing, Zhilin; Zhao, Tiantao; Gao, Yanhui; He, Zhi; Zhang, Lijie; Peng, Xuya; Song, Liyan

    2017-05-19

    Real-time CH4 oxidation in a landfill cover soil was studied using automated gas sampling that determined biogas (CH4 and CO2) and O2 concentrations at various depths in a simulated landfill cover soil (SLCS) column reactor. The real-time monitoring system obtained more than 10,000 biogas (CH4 and CO2) and O2 data points covering 32 steady states of CH4 oxidation with 32 different CH4 fluxes (0.2-125mol·m(-2)·d(-1)). The kinetics of CH4 oxidation at different depths (0-20cm, 20-40cm, and 40-60cm) of SLCS were well fit by a CH4-O2 dual-substrate model based on 32 values (averaged, n=5-15) of equilibrated CH4 concentrations. The quality of the fit (R(2) ranged from 0.90 to 0.96) was higher than those reported in previous studies, which suggests that real time monitoring is beneficial for CH4 oxidation simulations. MiSeq pyrosequencing indicated that CH4 flux events changed the bacterial community structure (e.g., increased the abundance of Bacteroidetes and Methanotrophs) and resulted in a relative increase in the amount of type I methanotrophs (Methylobacter and Methylococcales) and a decrease in the amount of type II methanotrophs (Methylocystis). Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Assessing methane oxidation under landfill covers and its contribution to the above atmospheric CO{sub 2} levels: The added value of the isotope ({delta}{sup 13}C and {delta}{sup 18}O CO{sub 2}; {delta}{sup 13}C and {delta}D CH{sub 4}) approach

    SciTech Connect

    Widory, D.; Proust, E.; Bellenfant, G.; Bour, O.

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Comparison of the isotope and mass balance approaches to evaluate the level of methane oxidation within a landfill. Black-Right-Pointing-Pointer The level of methane oxidation is not homogenous under the landfill cover and is strongly correlated to the methane flux. Black-Right-Pointing-Pointer Isotope tracking of the contribution of the methane oxidation to the CO{sub 2} concentrations in the ambient air. - Abstract: We are presenting here a multi-isotope approach ({delta}{sup 13}C and {delta}{sup 18}O of CO{sub 2}; {delta}{sup 13}C and {delta}D of CH{sub 4}) to assess (i) the level(s) of methane oxidation during waste biodegradation and its migration through a landfill cover in Sonzay (France), and (ii) its contribution to the atmospheric CO{sub 2} levels above the surface. The isotope approach is compared to the more conventional mass balance approach. Results from the two techniques are comparable and show that the CH{sub 4} oxidation under the landfill cover is heterogenous, with low oxidation percentages in samples showing high biogas fluxes, which was expected in clay covers presenting fissures, through which CH{sub 4} is rapidly transported. At shallow depth, more immobile biogas pockets show a higher level of CH{sub 4} oxidation by the methanotrophic bacteria. {delta}{sup 13}C of CO{sub 2} samples taken at different heights (from below the cover up to 8 m above the ground level) were also used to identify and assess the relative contributions of its main sources both under the landfill cover and in the surrounding atmosphere.

  9. Improved dissolved oxygen status following removal of exotic weed mats in important fish habitat lagoons of the tropical Burdekin River floodplain, Australia.

    PubMed

    Perna, Colton; Burrows, Damien

    2005-01-01

    The Burdekin delta floodplain, north Queensland, is highly modified for agricultural purposes. Riparian condition is very poor and exotic aquatic weeds dominate waterways. Historically, most streams and lagoons were highly seasonal, but those now used for the delivery of irrigation water maintain elevated flows and increased turbidity and nutrient loading. These factors have aided exotic weed growth and many major lagoons are covered by dense water hyacinth (Eichhornia crassipes) mats which greatly reduce dissolved oxygen levels, one of the most important water quality variables for aquatic fauna. Mechanical harvesting of water hyacinth from several of these lagoons resulted in rapid and substantial increases in dissolved oxygen saturation, and improved suitability of the habitat to support fish species. Decrease in dissolved oxygen as water passes sequentially through weed-infested lagoons, justified the approach of harvesting upstream lagoons first, however, the channels that connect these lagoons remain weed-infested and are still impacting upon downstream oxygen levels.

  10. Assessing confinement in coastal lagoons.

    PubMed

    Canu, Donata Melaku; Solidoro, Cosimo; Umgiesser, Georg; Cucco, Andrea; Ferrarin, Christian

    2012-11-01

    Measures of transport scale in aquatic systems can contribute to the formulation of definitions of indicators of the system's ecological properties. This paper addresses confinement, a specific transport scale proposed by biological scientists as a parameter that can capture and synthesize the principal properties that determine the spatial structure of biological communities in transitional environments. Currently, there is no direct experimental measure of confinement. In this study, a methodology based on the accumulation rate within a lagoon of a passive tracer of marine origin is proposed, the influences of different factors in the calculation of confinement are analyzed, and general recommendations are derived. In particular, we analyze the spatial and the temporal variability of confinement and its sensitivity to the seasonal variability of climatic forcing, the inputs from rivers and the parameterization of the tidal exchanges. The Lagoon of Venice is used as a case study. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Spatial distribution, enrichment, and source of environmentally important elements in Batticaloa lagoon, Sri Lanka.

    PubMed

    Adikaram, Madurya; Pitawala, Amarasooriya; Ishiga, Hiroaki; Jayawardana, Daham

    2017-01-01

    The present paper is the first documentation of distribution and contamination status of environmentally important elements of superficial sediments in the Batticaloa lagoon that is connected to the largest bay of the world. Surface sediment samples were collected from 34 sites covering all over the lagoon. Concentrations of elements such as As, Cr, Cu, Fe, Nb, Ni, Pb, Sc, Sr, Th, V, Y, Zn, and Zr were measured by X-ray florescence analysis. Geochemically, the lagoon has three different zones that were influenced mainly by fresh water sources, marine fronts, and intermediate mixing zones. The marine sediment quality standards indicate that Zr and Th values are exceeded throughout the lagoon. According to the freshwater sediment quality standards, Cr levels of all sampling sites exceed the threshold effect level (TEL) and 17 % of them are even above the probable effect level (PEL). Most sampling sites of the channel discharging areas show minor enrichment of Cu, Ni, and Zn with respect to the TEL. Contamination indices show that the lagoon mouth area is enriched with As. Statistical analysis implies that discharges from agricultural channel and marine fluxes of the lagoon effects on the spatial distribution of measured elements. Further research is required to understand the rate of contamination in the studied marine system.

  12. Computer optimization of landfill-cover design

    SciTech Connect

    Massmann, J.W.; Moore, C.A.

    1982-12-01

    A finite difference computer program to aid optimizing landfill-cover design was developed. The program was used to compare the methane yield from sand-covred and clay-covered landfills equipped with methane-recovery systems. The results of this comparison indicate a clay cover can restrict air inflow into the landfill system, thus preventing oxygen poisoning of the methane-producing organisms. The practice of monitoring methane-to-air ratios in the pipelines of the recovery system in order to warn of oxygen infiltration into the fill material was shown to be ineffective in some situations. More-reliable methods to forewarn of oxygen poisoning are suggested.

  13. Seasonal and temporal dynamics of macrophytic assemblages and abiotic parameters of coastal lagoons in Western Greece (Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Christia, Chrysoula; Papastergiadou, Eva

    2014-05-01

    Coastal lagoons are considered naturally stressed systems that experience frequent environmental disturbances and fluctuations and they are usually considered as physically controlled ecosystems. Coastal lagoons of Western Greece are representative of four different lagoon types covering a wide range of physiographical and hydrological characteristics. The seasonal differences in the physico-chemical parameters monitored from 2005 to 2007 were reduced in lagoon types (II and III) which characterized by better seawater communication when compared with the chocked lagoon types (Type I and IV). The latter types showed lower salinity values and high nutrient concentrations especially during the wet period. The macrophytic assemblages of coastal lagoons are typically dominated by few genera with great environmental plasticity and salinity competition, among other structuring abiotic variables. The implementation of DCA analysis revealed five distinct macrophytic assemblages in which dominant species were the angiosperms Zostera noltii, Ruppia cirrhosa, Cymodocea nodosa, Potamogeton pectinatus, the charophytes Lamprothamnium papulosum and Chara hispida f. corfuensis, as well as species preferring more marine conditions such as Acanthophora nayadiformis and Cystoseira barbata. The lagoon type IV differs from all other distinguished lagoon types due to the dominance of the species Potamogeton pectinatus and the charophyte Chara hispida f. corfuensis. Regarding the macrophytic assemblages and the univariate variables, important differences were recorded between lagoon types. Chocked lagoons showed low number of species and Shannon diversity index comparing with restricted lagoon types (Types II and III). The multiple linear regression analysis showed that transparency, pH, nitrates, alkalinity and Chl-a could affect the values of the above variables. A decline of angiosperms was referred on a worldwide scale and recorded also in coastal lagoons of Western Greece. A gradual

  14. Sinking methane.

    PubMed

    Reay, David S

    2003-02-01

    Concentrations of the powerful greenhouse gas, methane, in our atmosphere have doubled since the beginning of the industrial age. Reducing these levels is a vital part of global efforts to combat global warming. Could we make use of the Earth's own methane sinks?

  15. Denitrification enzyme activity in swine wastewater lagoons

    USDA-ARS?s Scientific Manuscript database

    Anaerobic lagoons are typically used for treatment of swine wastewater. Although these anaerobic lagoons were once thought to be relatively simple in their physical, chemical, and biological processes, they are actually very sophisticated. Recent reports of high levels of di-nitrogen emissions and h...

  16. Taphonomy of coral reefs from Southern Lagoon of Belize

    SciTech Connect

    Westphall, M.J.; Ginsburg, R.N.

    1985-02-01

    The Southern Lagoon of the Belize barrier complex, an area of some 600 km/sup 2/, contains a tremendous number of lagoon reefs, which range in size from patches several meters across to rhomboidal-shaped structures several kilometers in their long dimension. These lagoon reefs are remarkable because they have Holocene sediment accumulations in excess of 13 m consisting almost entirely of coral debris and lime mud and sand, and rise up to 30 m above the surrounding lagoon floor with steeply sloping sides (50-80/sup 0/), yet are totally uncemented. The reef-building biota and their corresponding deposits were studied at a representative reef, the rhomboidal complex of Channel Cay. As with many of the reefs in this area, the steeply sloping flanks of Channel Cay are covered mainly by the branched staghorn coral Acropora cervicornis and ribbonlike and platy growth of Agaricia spp. The living corals are not cemented to the substrate, but are merely intergrown. Fragmented pieces of corals accumulate with an open framework below the living community; this open framework is subsequently infilled by lime muds and sands produced mainly from bioerosion. Results from probing and coring suggest that the bafflestone fabric of coral debris and sediment extends at least 13 m into the subsurface. Radiocarbon-age estimates indicate these impressive piles of coral rubble and sediment have accumulated in the past 9000 yr (giving a minimum accumulation rate of 1.4 m/1000 yr) and illustrate the potential for significant carbonate buildups without the need for early lithification.

  17. Sediment characteristics and water quality in the two hyper-saline lagoons along the Red Sea coast of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Rasul, Najeeb; Al-Farawati, Radwan; Al-Harbi, Omer; Naser Qutub, Abdul

    2013-04-01

    widens. In the case of Khawr ash Shaibah al Masdudah the mouth is wide and it faces the open sea directly, whereas the mouth of Khawr ash Shaibah al Maftuhah, although narrower, the tidal current is only strong until the channel to the lagoon bends almost 90° where the tidal current dissipates, resulting in the restricted water and sediment movement in the lagoon. The coarser sediments are stained gray-black because of a reducing environment and formation of authigenic pyrite. Stagnant condition prevails inside the lagoons because of insufficient exchange of water with the open sea and lack of rainfall causes hyper-saline conditions. Higher salinity values were evident in the shallow waters, whereas oxygen saturation ranged between 77 % (southern lagoon) and 107 % (northern lagoon) which could be attributed to the complex nature of the southern lagoon. Reactive phosphate and nitrite concentrations in the surface waters were low and in many locations under the detection limit reflecting the oligotrophic behaviour of the Red Sea and limited supply of nutrients from adjacent areas. There is an abundant presence of trace metals especially in fine sediments that has the tendency to adsorb the metals more efficiently. There is an inverse correlation between heavy metals and carbonate content in the sediments, and much stronger particularly with Cr, V and Co. The Landsat ETM identifies two depth zones in the lagoons and shows the effects of the influence of flooding and ebbing on the sediment distribution and the extent of the water cover seasonally.

  18. Use of Shallow Lagoon Habitats by Nekton of the Northeastern Gulf of Mexico

    EPA Science Inventory

    We compared nekton use of prominent habitat types within a lagoonal system of the northeastern Gulf of Mexico (GoM). These habitat types were defined by combinations of structure (cover type) and location (distance from shore) as: Spartina edge (<1m from shore), Spartina 3 m from...

  19. Use of Shallow Lagoon Habitats by Nekton of the Northeastern Gulf of Mexico

    EPA Science Inventory

    We compared nekton use of prominent habitat types within a lagoonal system of the northeastern Gulf of Mexico (GoM). These habitat types were defined by combinations of structure (cover type) and location (distance from shore) as: Spartina edge (<1m from shore), Spartina 3 m from...

  20. Effects of regional climate changes on the planktonic ecosystem and water environment in the frozen Notoro Lagoon, northern Japan.

    PubMed

    Katsuki, Kota; Seto, Koji; Noguchi, Takuro; Sonoda, Takeshi; Kim, JuYong

    2012-10-01

    Diatom fossils from core sediments and living diatoms from water samples of Notoro Lagoon in northern Japan were examined to evaluate natural climate effects on lagoon environmental changes. In 1974, the artificial inlet was excavated. Immediately after, the anoxic bottom water in Notoro Lagoon began to disappear due to an increasing water exchange rate. However, chemical oxygen demand (COD) in the bottom water of Notoro Lagoon gradually increased, with fluctuations, during the last 30 years. In addition, the dominant diatom assemblages in Notoro Lagoon shifted to ice-related and spring bloom taxa after the excavation. The dominant taxa of each year in the sediment core were also strongly related to the timing of lagoon ice melting. This is because the COD in Notoro Lagoon was affected by the deposited volume of blooming diatoms, which was controlled by the duration of ice cover and the timing of ice discharge to the Okhotsk Sea likely due to an air pressure pattern change over the northern North Pacific like the Pacific Decadal Oscillation (PDO).

  1. Aerated Lagoons. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This student manual contains the textual material for a unit which focuses on the structural and operationally unique features of aerated lagoons. Topic areas discussed include: (1) characteristics of completely mixed aerated lagoons; (2) facultative aerated lagoons; (3) aerated oxidation ponds; (4) effects of temperature on aerated lagoons; (5)…

  2. High performance aerated lagoon systems

    SciTech Connect

    Rich, L.

    1999-08-01

    At a time when less money is available for wastewater treatment facilities and there is increased competition for the local tax dollar, regulatory agencies are enforcing stricter effluent limits on treatment discharges. A solution for both municipalities and industry is to use aerated lagoon systems designed to meet these limits. This monograph, prepared by a recognized expert in the field, provides methods for the rational design of a wide variety of high-performance aerated lagoon systems. Such systems range from those that can be depended upon to meet secondary treatment standards alone to those that, with the inclusion of intermittent sand filters or elements of sequenced biological reactor (SBR) technology, can also provide for nitrification and nutrient removal. Considerable emphasis is placed on the use of appropriate performance parameters, and an entire chapter is devoted to diagnosing performance failures. Contents include: principles of microbiological processes, control of algae, benthal stabilization, design for CBOD removal, design for nitrification and denitrification in suspended-growth systems, design for nitrification in attached-growth systems, phosphorus removal, diagnosing performance.

  3. Breaking methane

    PubMed Central

    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. PMID:25607367

  4. Reconstruction of historic sea ice conditions in a sub-Arctic lagoon

    USGS Publications Warehouse

    Petrich, Chris; Tivy, Adrienne C.; Ward, David H.

    2014-01-01

    Historical sea ice conditions were reconstructed for Izembek Lagoon, Bering Sea, Alaska. This lagoon is a crucial staging area during migration for numerous species of avian migrants and a major eelgrass (Zostera marina) area important to a variety of marine and terrestrial organisms, especially Pacific Flyway black brant geese (Branta bernicla nigricans). Ice cover is a common feature of the lagoon in winter, but appears to be declining, which has implications for eelgrass distribution and abundance, and its use by wildlife. We evaluated ice conditions from a model based on degree days, calibrated to satellite observations, to estimate distribution and long-term trends in ice conditions in Izembek Lagoon. Model results compared favorably with ground observations and 26 years of satellite data, allowing ice conditions to be reconstructed back to 1943. Specifically, periods of significant (limited access to eelgrass areas) and severe (almost complete ice coverage of the lagoon) ice conditions could be identified. The number of days of severe ice within a single season ranged from 0 (e.g., 2001) to ≥ 67 (e.g., 2000). We detected a slight long-term negative trend in ice conditions, superimposed on high inter-annual variability in seasonal aggregate ice conditions. Based on reconstructed ice conditions, the seasonally cumulative number of significant or severe ice days correlated linearly with mean air temperature from January until March. Further, air temperature at Izembek Lagoon was correlated with wind direction, suggesting that ice conditions in Izembek Lagoon were associated with synoptic-scale weather patterns. Methods employed in this analysis may be transferable to other coastal locations in the Arctic.

  5. Hydrologic characteristics of lagoons at San Juan, Puerto Rico, during an October 1974 tidal cycle

    USGS Publications Warehouse

    Gómez-Gómez, Fernando; Ellis, S.R.

    1983-01-01

    Flow and water-quality changes were studied during a period of intense rainfall in the San Juan Lagoon system. The study covered a 25-hour period beginning 0900 hours 22 October, 1974. Precipitation during the study period averaged 70 millimeters. Sampling stations were located at Boca de Cangrejos, the main ocean outlet; Canal Pinones between Laguna de Pinones and Laguna La Torrecilla; Canal Suarez between Laguna San Jose, connects to Laguna La Torrecilla; and Cano de Martin Pena between Laguna San Jose and Bahia de San Juan. In addition water-elevation recording gages were installed at each lagoon. Water samples from the canal stations were analyzed for organic carbon, nitrogen and phosphorus species, and suspended sediment. Specific-conductance measurements were used with the chemical data to estimate the runoff contributions of nutrients. Runoff into the lagoon, system during the study period was about 2.8 million cubic meters, or about 70 percent of the average precipitation. The runoff contributed chemical loadings to the lagoons of 95,000 kilograms total-organic carbon; 2,700 kilograms of total phosphorus; and 10,000 kilograms of total Khjeldhal nitrogen. A comparison with a prior study during which there was no significant rain, show that dry-period loadings are less than 10 percent of the wet-period loadings. At the end of the study period the system had not reached equilibrium, and the lagoons retained 80 percent of the water inflows from 50 to 90 percent of the chemical loads. Nearly 95 percent of the water outflows occurred at the Boca de Cangrejos sea outlet. The three lagoons and interconnecting canals form a very complex hydraulic system that is difficult to study using traditional techniques. A model of the system will facilitate management to improve the quality of water in the lagoons.

  6. Sedimentation in lagoon waters (Case study on Segara Anakan Lagoon)

    NASA Astrophysics Data System (ADS)

    Sari, Lilik Kartika; Adrianto, Luky; Soewardi, Kadarwan; Atmadipoera, Agus S.; Hilmi, Endang

    2016-05-01

    This study aims to demonstrate the effect of sedimentation on waters area that serves as an advocate for life. It is included in the category to be wary considering these conditions will reduce the quality of life and threaten the life and survival of endemic biota. Observations rate of sedimentation since April 2014 until March 2015 performed at 6 stations that are considered to represent the condition of the lagoon. The observations for rate of sedimentation was conducted twice in a month for one year. Oceanographic parameters was taken by CTD (Conductivity, Temperature, and Depth) sensor in two seasons, at the height of the rainy season, March 2014 and August 2014. Results showed that the aquatic area more narrow characterized by changes in the outside line of the island visible on the image observation for two decades.

  7. Methane Emissions from Upland Trees

    NASA Astrophysics Data System (ADS)

    Pitz, S.; Megonigal, P.; Schile, L. M.; Szlavecz, K. A.; King, K.

    2013-12-01

    Most work on methane (CH4) emissions from natural ecosystems has focused on wetlands and wetland soils because they are predictable emitters and relatively simple to quantify. Less attention has been directed toward upland ecosystems that cover far larger areas, but are assumed to be too dry to emit CH4. There is abundant evidence that upland ecosystems emit small amounts of CH4 during hot moments that collectively constitute a significant source in the global budget of this potent greenhouse gas. We have established two transects across natural moisture gradients in two forests near Annapolis, Maryland. Both tree and soil methane fluxes were measured using chamber methods. Each tree chamber was custom fit to the stem near the base. In addition, porewater methane concentrations were collected at multiple depths near trees. Abiotic parameters such as soil temperature, soil moisture, water potential, and depth to groundwater were monitored using a wireless sensor network. Upland emissions from tree stems were as high as 14.6 umoles CH4 m-2 hr-1 while the soil uptake was -1.5 umoles CH4 m-2 hr-1. These results demonstrate that tree methane emissions and soil methane uptake can occur simultaneously in a mesic forest. Factors controlling methane emissions were soil temperature, soil moisture, and depth to groundwater. Based on our preliminary data, tree mediated methane emissions may be offsetting the soil methane sink of upland forests by 20 to 30%. Future methane budgets and climate models will need to include tree fluxes and the parameters that control methane emissions for accurate accounting and predictions.

  8. Methane Recovery from Animal Manures The Current Opportunities Casebook

    SciTech Connect

    Lusk, P.

    1998-09-01

    Growth and concentration of the livestock industry create opportunities for the proper disposal of the large quantities of manures generated at dairy, swine, and poultry farms. Pollutants from unmanaged livestock wastes can degrade the environment, and methane emitted from decomposing manure may contribute to global climate change. One management system not only provides pollution prevention but also can convert a manure problem into a new profit center. Economic evaluations and case studies of operating systems indicate that the anaerobic digestion (AD) of livestock manures is a commercially available bioconversion technology with considerable potential for providing profitable coproducts, including a cost-effective renewable fuel for livestock production operations. This Casebook examines some of the current opportunities for the recovery of methane from the AD animal manures. U.S. livestock operations currently employ four types of anaerobic digester technology: slurry, plug-flow, complete-mix, and covered lagoon. An introduction to the engineering economies of these technologies is provided, and possible end-use applications for the methane gas generated by the digestion process are discussed. The economic evaluations are based on engineering studies of digesters that generate electricity from the recovered methane. Case studies of operating digesters, with project and maintenance histories and the operators ''lessons learned,'' are included as reality checks. Factors necessary for successful projects, as well as a list of reasons explaining why some AD projects fail, are provided. The role of farm management is key; not only must digesters be well engineered and built with high-quality components, they must also be sited at farms willing to incorporate the uncertainties of a new technology. More than two decades of research has provided much information about how manure can be converted to an energy source; however, the American farmer has not been motivated

  9. Movement of lagoon-liquor constituents below four animal-waste lagoons.

    PubMed

    DeSutter, Tom M; Pierzynski, Gary M; Ham, Jay M

    2005-01-01

    Movement of liquor constituents from animal-waste lagoons has the potential to degrade ground water quality. The depth of movement and concentrations of lagoon-liquor constituents in the soil underlying three cattle (Bos taurus)-waste retention lagoons and one swine (Sus scrofa)-waste lagoon were determined. Samples were taken by using a direct-push coring machine, dissected by depth, and analyzed for total N, organic C, CaCO3, pH, cation exchange capacity (CEC), texture, and extractable NO3, NH(4), P, Cl, Ca, Mg, K, and Na. Ammonium N concentrations were greatest in the upper 0.5 m of soil under all four lagoons with concentrations ranging from 94 to 1139 mg kg(-1). Organic N was determined to make up between 39 and 74% of the total N beneath all lagoons. The swine lagoon had 2.4 kg N m(-2) in the underlying soil whereas the cattle lagoon with highest quantity of N had 1.2 kg N m(-2) in the underlying soil. Although N concentrations decreased with depth, N was greater than expected background levels at the bottom of some cores, indicating that the sampling efforts did not reach the bottom of the N plume. Nitrate N concentrations were generally less than 5 mg kg(-1) immediately below the lagoon floor. In the uppermost 0.5 m of soil underlying the swine and three cattle lagoons, NH4+ occupied 44% and between 1 and 22% of the soil cation exchange sites, respectively. The depth of movement of N under these lagoons, as much as 4 m, may pose remediation difficulties at lagoon closure.

  10. [The mangrove and others vegetation associations in de Gandoca lagoon, Limón, Costa Rica].

    PubMed

    Coll, M; Fonseca, A C; Cortés, J

    2001-12-01

    Six plant associations were identified at Gandoca Lagoon by photointerpretation and field verification: a) mangroves, b) palm trees swamp, and palm trees with Acrostichum aureum and A. danaefolium, c) mixed palm trees, d) very humid tropical rain forest, and e) tropical beach vegetation. The mangroves cover 12.5 ha surrounding the lagoon and extend 2 km up the Gandoca River. Rhizophora mangle (red mangrove) was the dominant species, with Avicennia germinans (black mangrove), Laguncularia racemosa (white mangrove) and Conocarpus erectus (buttonwood) also present. Moving inland the mangroves grade into a tropical rain forest. Gandoca, the largest and best preserved mangrove of Caribbean Costa Rica, tripled its area from 1976 to 2000. Possible causes include sedimentation and the Limón earthquake, which may have subside the lagoon area.

  11. Depositional history and fault-related studies, Bolinas Lagoon, California

    USGS Publications Warehouse

    Berquist, Joel R.

    1978-01-01

    Studies of core sediments and seismic reflection profiles elucidate the structure and depositional history of Bolinas Lagoon, Calif., which covers 4.4 km 2 and lies in the San Andreas fault zone at the southeast corner of the Point Reyes Peninsula 20 km northwest of San Francisco. The 1906 trace of the San Andreas fault crosses the west side of the lagoon and was determined from (1) tectonically caused salt-marsh destruction indicated by comparison of 1854 and 1929 U.S. Coast and Geodetic Survey (U.S.C. & G.S.) topographic surveys, (2) formation of a tidal channel along the border of destroyed salt marshes, and (3) azimuths of the trend of the fault measured in 1907. Subsidence in the lagoon of 30 cm occurred east of the San Andreas fault in 1906. Near the east shore, seismic-reflection profiling indicates the existence of a graben fault that may connect to a graben fault on the Golden Gate Platform. Comparison of radiocarbon dates on shells and plant debris from boreholes drilled on Stinson Beach spit with a relative sea-level curve constructed for southern San Francisco Bay indicates 5.8 to more than 17.9 m of tectonic subsidence of sediments now located 33 m below mean sea level. Cored sediments indicate a marine transgression dated at 7770?65 yrs B.P. overlying freshwater organic-rich lake deposits. Fossil pollen including 2 to 8 percent Picea (spruce) indicate a late Pleistocene (?)-Early Holocene climate, cooler, wetter, and foggier than at present. Above the transgression are discontinuous and interfingering sequences of transgressive-regressive marine, estuarine, and barrier sediments that reflect rapid lateral and vertical shifts of successive depositional environments. Fossil megafauna indicate (1) accumulation in a protected, shallow-water estuary or bay, and (2) that the lagoon was probably continuously shallow and never a deep-water embayment. Analysis of grain-size parameters, pollen frequencies, and organic remains from a core near the north end of

  12. Methane emissions from MBT landfills

    SciTech Connect

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

    2013-09-15

    Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: 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{sup 3} CH{sub 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{sub 4}/(m{sup 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

  13. Lower Brule Lagoon System NPDES Permit

    EPA Pesticide Factsheets

    Under NPDES permit number SD-0020800, Lower Brule Rural Water is authorized to discharge from its wastewater lagoon system serving the town of Lower Brule, located in Lyman County, South Dakota, to the bank of the Missouri River (Lake Sharpe).

  14. Evolutionary resilience and complex lagoon systems.

    PubMed

    Davoudi, Simin; Zaucha, Jacek; Brooks, Elizabeth

    2016-10-01

    The present study applies an evolutionary resilience framework to complex socioecological systems in the coastal regions in Europe with a particular focus on lagoons. Despite their variations, lagoons share common challenges in achieving effective and sustainable ways of governing and managing economic, social, and environmental uncertainties. Our aim is to demonstrate that building resilience involves planning not only for recovery from shocks but also for cultivating preparedness and seeking potential transformative opportunities that emerge from change. The framework consists of 4 dimensions: persistence, adaptability, transformability, and preparedness. To illustrate how this 4-dimensional framework can be applied to the specific context of lagoons, we draw on examples of good and poor practices from the 10 lagoons studied as part of the ARCH project. Integr Environ Assess Manag 2016;12:711-718. © 2016 SETAC. © 2016 SETAC.

  15. Into the Depths of the Lagoon Nebula

    NASA Image and Video Library

    2011-09-16

    Swirling dust clouds and bright newborn stars dominate the view in this image of the Lagoon nebula from NASA Spitzer Space Telescope. The nebula lies in the general direction of the center of our galaxy in the constellation Sagittarius.

  16. Hydrodynamic Modeling of Diego Garcia Lagoon

    DTIC Science & Technology

    2014-08-01

    largest coral reef atoll of more than 60 islands that make up the Chagos Archipelago south of the equator in the central Indian Ocean. It is located at...quality and coral reef health. Hydrodynamic modeling of lagoon waters is one key component of the investigation to understand lagoon circulation...NAVFAC and other researchers will then use the flushing time information to assess water quality conditions and coral reef health. Researchers use

  17. [Nutrients in 39 Mexican coastal lagoons].

    PubMed

    Contreras, F; Castañeda, O; Torres-Alvarado, R; Gutiérrez, F

    1996-08-01

    An analysis of 39 Mexican coastal lagoons most in tropical environments, shows no nutrient limitation for primary productivity: even minimum nutrient values are higher than those of similar systems (mostly of temperate zones). In some cases, nutrient variations are large and indicative of heterogeneity. The N:P ratio is more important than simple nutrient concentrations. Using this ratio, coastal lagoons are classified as limited in nitrogen (< 5) or phosphorus (> 10).

  18. Tracing anthropogenically driven groundwater discharge into a coastal lagoon from southern Brazil

    NASA Astrophysics Data System (ADS)

    Santos, Isaac R.; Niencheski, Felipe; Burnett, William; Peterson, Richard; Chanton, Jeffrey; Andrade, Carlos F. F.; Milani, Idel B.; Schmidt, Axel; Knoeller, Kay

    2008-05-01

    SummaryWe investigated the distribution of naturally occurring geochemical tracers ( 222Rn, 223Ra, 224Ra, 226Ra, CH 4, δ18O, and δ2H) in the water column and adjacent groundwater of Mangueira Lagoon as proxies of groundwater discharge. Mangueira Lagoon is a large (90 km long), shallow (˜4-5 m deep), fresh, and non-tidal coastal lagoon in southern Brazil surrounded by extensively irrigated rice plantations and numerous irrigation canals. We hypothesized that the annual, intense irrigation for rice agriculture creates extreme conditions that seasonally change groundwater discharge patterns in the adjacent lagoon. We further supposed that dredging of irrigation canals alters groundwater fluxes. While the activities of 222Rn in shallow groundwater were 2-3 orders of magnitude higher than in surface water, CH 4 and radium isotopes were only ˜1 order of magnitude higher. Therefore, 222Rn appears to be the preferred groundwater tracer in this system. Radon concentrations and conductivities were dramatically higher near the pump house of rice irrigation canals, consistent with a groundwater source. Modeling of radon inventories accounting for total inputs (groundwater advection, diffusion from sediments, and decay of 226Ra) and losses (atmospheric evasion, horizontal mixing and decay) indicated that groundwater advection rates in the irrigation canals (˜25 cm/d) are over 2 orders of magnitude higher than along the shoreline (˜0.1 cm/d). Nearly 75% of the total area of the canals is found in the southern half of the lagoon, where groundwater inputs seem to be higher as also indicated by methane and stable isotope trends. In spite of the relatively small area of the canals, we estimate that they contribute nearly 70% of the total (˜57,000 m 3/d) groundwater input into the entire Mangueira Lagoon. We suggest that the dredging of these canals cut through aquitards which previously restricted upward advection from the underlying permeable strata. The irrigation channels

  19. Water hyacinths for upgrading sewage lagoons to meet advanced wastewater treatment standards, part 2

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.

    1976-01-01

    Field tests using water hyacinths as biological filtration agents were conducted in the Mississippi gulf coast region. The plants were installed in one single cell and one multiple cell sewage lagoon systems. Water hyacinths demonstrated the ability to maintain BOD5 and total suspended solid (TSS) levels within the Environmental Protection Agency's prescribed limits of 30 mg/lBOD5 and 30 mg/l TSS. A multiple cell sewage lagoon system consisting of two aerated and one water hyacinth covered cell connected in series demonstrated the ability to maintain BOD5 and TSS levels below 30 mg/l year-round. A water hyacinth covered lagoon with a surface area of 0.28 hectare containing a total volume of 6.8 million liters demonstrated the capacity to treat 437,000 to 1,893,000 liters of sewage influent from 2.65 hectares of aerated lagoons daily and produce an effluent that met or exceeded standards year-round.

  20. Landfill Liners and Covers: Properties and Application to Army Landfills.

    DTIC Science & Technology

    1984-06-01

    sands and gravels were used for cover material. Several moni- toring points placed through and around the landfill defined the area of groundwater ... pollution . 2 1H. Dratfield and L. Mavtone, personal communication. 53 0 O GAS VENT 2’ FINAL COVER TREATMENT NEW- LAGOON W LT WAT _ LEACHATE COLLECTION

  1. Methane Painting

    NASA Image and Video Library

    2015-09-07

    Why does Saturn look like it's been painted with a dark brush in this infrared image, but Dione looks untouched? Perhaps an artist with very specific tastes in palettes? The answer is methane. This image was taken in a wavelength that is absorbed by methane. Dark areas seen here on Saturn are regions with thicker clouds, where light has to travel through more methane on its way into and back out of the atmosphere. Since Dione (698 miles or 1,123 kilometers across) doesn't have an atmosphere rich in methane the way Saturn does, it does not experience similar absorption -- the sunlight simply bounces off its icy surface. Shadows of the rings are seen cast onto the planet at lower right. This view looks toward Saturn from the unilluminated side of the rings, about 0.3 degrees below the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on May 27, 2015 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 728 nanometers. http://photojournal.jpl.nasa.gov/catalog/PIA18336

  2. Landfill Methane

    USDA-ARS?s Scientific Manuscript database

    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...

  3. Identifying nutrient sources to three lagoons at Ofu and Olosega, American Samoa using δ15N of benthic macroalgae

    USGS Publications Warehouse

    Garrison, Virginia H.; Kroeger, Kevin D.; Fenner, Douglas; Craig, Peter

    2007-01-01

    Degradation of nearshore habitats is a serious problem in some areas of American Samoa, such as in Pago Pago Harbor on Tutuila Island, and is a smaller but chronic problem in other areas. Sedimentation, pollution, nutrient enrichment from surface runoff or groundwater, and trampling are the major factors causing the changes (Peshut and Brooks, 2005). On the outer islands of Ofu and Olosega (Manu’a Islands; Fig. 1), there is an interesting contrast between relatively pristine lagoon habitats not far from comparatively degraded lagoon habitats. To’aga lagoon on the southeast side of Ofu Island (Fig. 1) has clear waters, a high diversity of corals and fishes, no human habitations, and an undeveloped watershed with no streams. To’aga lagoon is within the boundaries of the National Park of American Samoa and is the site of long-term research on coral reef resilience and global climate change. Only 3 km to the east of To’aga is a degraded lagoon that fronts Olosega Village. The Olosega lagoon is similar in size but has significantly less live coral than To’aga, and blooms of filamentous algae have been reported to cover the Olosega lagoon/reef flat bottom (unpublished data, PC; Fig. 2). The islands are influenced by the same regional-scale and biogeochemical regimes, and both islands are remnants of a volcanic caldera (Craig, 2005). Thus, local factors operating on the scale of a kilometer or less are thought to be driving the differences observed between lagoons. Land disturbance is limited to a road linking the villages, the clearing of vegetation for buildings, and two village dump sites located on the narrow strip of land between the steep slopes of the islands and the shoreline; there is no industry or associated pollution on either island. Cesspools are used for sewage disposal. Nutrient enrichment (from cesspools) of groundwater and the lagoon, as well as trampling during gleaning of reef organisms, are possible factors affecting the spatial relief

  4. Flushing of a coastal lagoon in the Red Sea

    NASA Astrophysics Data System (ADS)

    Sultan, S. A. R.; Ahmad, F.

    1990-09-01

    Shu'aiba Lagoon (Lat. 20°45'N; Long. 39°28'E) is located on the eastern coast of the Red Sea. It is relatively shallow with an area of approximately 11·7 km 2. The inlet to the lagoon is narrow with a cross-sectional area of about 245 m 2. This lagoon is a future site to develop mariculture. With this objective in view the flushing time scale of the lagoon was calculated, as flushing is an important abiotic factor in lagoon ecology. The average flushing time for the months February to June and September to November is about 20 days. Oceanic inputs play an important part in the process of fertilization of the lagoons. The marine environment in arid zone lagoons is under natural stress due to high temperatures and salinities. However, the flushing time scale of 20 days may not exert intolerable stress on the ecology of the Shu'aiba Lagoon.

  5. The fate of Mediterranean lagoons under climate change

    NASA Astrophysics Data System (ADS)

    Umgiesser, Georg; Ferrarin, Christian; Cucco, Andrea; De Pascalis, Francesca; Ghezzo, Michol; Bellafiore, Debora; Bajo, Marco

    2014-05-01

    A numerical model (SHYFEM) has been applied to 10 Mediterranean lagoons and a comparison study between the lagoons has been carried out. The lagoons are the lagoons of Venice, Marano-Grado, Varano and Lesina in the Adriatic Sea, the Taranto basin in the Ionian Sea, the Cabras lagoon in Sardinia, and the lagoons of Ganzirri and Faro in Sicily, the Mar Menor in Spain and the Nador lagoon in Morocco. These lagoons give a representative picture of the lagoons situated around the Mediterranean basin. The lagoons range from a leaky type of lagoons to a choked type. The number of inlets ranges from just one in the Nador lagoon to 6 in the case of the Marano-Grado lagoons. Tidal range is from nano-tidal to micro-tidal. The depth ranges from an average depth of 1 m to up to 40 meters. The model is a finite element model, especially suited to shallow water basins with complicated geometric and morphologic variations. The model can compute the basic hydrodynamics, dispersion of tracers, temperature and salinity evolution, sediment transport and ecological parameters. Building on an earlier study that focused on the classification of Mediterranean lagoons based on hydrodynamics, exchange rates and renewal time, this study is concerned with the changes in physical parameters under climate change. Data from IPCC has been used to simulate the changes in renewal time, salinity and temperature of all lagoons, with respect to the control simulation. Whenever possible downscaled data for the Mediterranean basin have been used. Sea level rise scenarios are taken from the last IPCC report. The model has been applied in its 3D version and the chosen setup allows a comparison between results in the different lagoons. Results indicate that the differences of renewal time between all studied lagoons become smaller. This means that leaky lagoons become less leaky and choked lagoons less choked. What concerns temperature and salinity, changes occurring in the sea are amplified inside lagoons

  6. Observations on the methane oxidation capacity of landfill soils

    USDA-ARS?s Scientific Manuscript database

    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...

  7. [Factors involved in coastal lagoons formation in Colombian southwest Caribbean].

    PubMed

    Alvarez-León, Ricardo; Mendoza-Mazzeo, Luis Alberto; Vernette, Georges

    2003-01-01

    Based on origin, geomorphological evolution and environmental characteristics, four of the main types of coastal lagoons were identified in colombian southwest Caribbean. The following are examples of each type: (1) Terrigenous sediment inputs in delta environment (Lagoons from Sinu River Delta, Cordoba Department), (2) Shore sand bars in coastal flat (Tesca Lagoon, Bolivar Deparment), (3) bar built by organisms such as coral reefs, (Isla Grande Lagoons, Bolivar Deparment) and, (4) bars controlled by tectonism (Cartagena Bay, Bolivar Deparment).

  8. Report to Congress: Municipal Wastewater Lagoon Study. Volume 1

    SciTech Connect

    Not Available

    1987-11-01

    This report presents the results of the Municipal Wastewater Lagoon Study performed by the USEPA in response to Section 3018 of RCRA and Sec. 246 of the Hazardous and Solid Waste amendments of 1984. The objectives are to determine: number and size of municipal lagoons; types and quantities of waste contained in such lagoons; the extent to which such waste has been or may be released from such lagoons and contaminates ground water; and available alternatives for preventing or controlling such releases.

  9. Nutrient-Chlorophyll Relationships in the Indian River Lagoon, Florida

    EPA Science Inventory

    The Indian River Lagoon is a highly diverse estuary located along Florida’s Atlantic coast. The system is made up of the main stem and two side-lagoons: the Banana River and Mosquito Lagoon. We segmented the main stem into three sections based on spatial trends in water quality ...

  10. Accuracy of lagoon gas emissions using an inverse dispersion method

    USDA-ARS?s Scientific Manuscript database

    Measuring gas emissions from treatment lagoons and storage ponds poses challenging conditions for existing micrometeorological techniques because of non-ideal wind conditions. These include those induced by trees and crops surrounding the lagoons, and lagoons with dimensions too small to establish ...

  11. Inverse-dispersion technique for assessing lagoon gas emissions

    USDA-ARS?s Scientific Manuscript database

    Measuring gas emissions from treatment lagoons and storage ponds poses challenging conditions for existing micrometeorological techniques because of non-ideal wind conditions, such as those induced by trees and crops surrounding the lagoons, and lagoons with dimensions too small to establish equilib...

  12. Nutrient-Chlorophyll Relationships in the Indian River Lagoon, Florida

    EPA Science Inventory

    The Indian River Lagoon is a highly diverse estuary located along Florida’s Atlantic coast. The system is made up of the main stem and two side-lagoons: the Banana River and Mosquito Lagoon. We segmented the main stem into three sections based on spatial trends in water quality ...

  13. Facultative Lagoons. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    The textual material for a unit on facultative lagoons is presented in this student manual. Topic areas discussed include: (1) loading; (2) microbial theory; (3) structure and design; (4) process control; (5) lagoon start-up; (6) data handling and analysis; (7) lagoon maintenance (considering visual observations, pond structure, safety, odor,…

  14. Methane flux time series for tundra environments

    SciTech Connect

    Whalen, S.C.; Reeburgh, W.E. )

    1988-12-01

    Seasonal measurements of net methane flux were made at permanent sites representing important components of arctic tundra. The sites include Eriophorum tussocks, intertussock depressions, moss-covered areas, and Carex stands. Methane fluxes showed high diel, seasonal, intra site, and between site variability. Eriophorum tussocks and Carex dominated methane release to the atmosphere, with mean annual net methane fluxes of 8.05 + or{minus}2.50 g CH{sub 4}/sq m and 4.88 + or{minus}0.73 g CH{sub 4}/sq m, respectively. Methane fluxes form the moss sites and intertussock depressions were much lower. Over 90% of the mean annual methane flux from the Eriophorum, intertussock depressions, and Carex sites occurred between thaw and freeze-up. Some 40% of the mean annual methane flux from the moss sites occurred during winter. Composite methane fluxes for tussock tundra and Carex-dominated wet meadow tundra environments were produced by weighting measured component fluxes according to areal coverage. Tussock and wet meadow tundra account for an estimated global methane emission of 19-33 Tg/yr. 39 refs., 7 figs., 2 tabs.

  15. Coalbed Methane Outreach Program

    EPA Pesticide Factsheets

    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.

  16. METHANE: INDUSTRIAL SOURCES

    EPA Science Inventory

    The chapter provides qualitative information on the magnitude of industrial sources of methane and, where possible, provides information to allow the reader to quantify methane emissions. One difficulty in quantifying methane emissions from industry is the inconsistent treatment ...

  17. The Influence of Wind and Tide on the Hydrodynamics of a Highly Frictional Coastal Lagoon System

    NASA Astrophysics Data System (ADS)

    Polanco-Arias, C.; Marino-Tapia, I.; Enriquez, C.

    2016-02-01

    This study is focused on the influence of wind and tide on the hydrodynamics of a tropical coastal lagoon in Telchac, Yucatan, Mexico. The system is very shallow (z < 1m) and covered with a rim of mangrove forests, both aspects that enhance its frictional characteristics. The lagoon is an important habitat for the exotic flamingo birds and several species of fish, but also is used for fishing and serves as a harbor for small boats. Water level and velocity data gathered during one month in the summer of 2009, shows the expected attenuation of the tidal signal in the head of the system, but during the final ten days of the campaign there is an unusual behavior where the water level in the lagoon head was between 16% and 33% bigger than in the lagoon mouth. Analysis of the data shows a high coherence between the sea level and the wind velocity, primarily at diurnal frequencies. This reinforces the hypothesis of a synchronization between strong sea breezes and the predominant diurnal tide in such a way that amplification of the diurnal signal can occur at the head. Numerical simulations using the Delft3D model are performed to confirm this hypothesis and to better understand the conditions under which such phenomenon can occur. The effects of basin orientation, shape and depth are investigated with the numerical model.

  18. Vertical distribution of Arctic methane

    NASA Astrophysics Data System (ADS)

    Tukiainen, Simo; Karppinen, Tomi; Hakkarainen, Janne; Kivi, Rigel; Heikkinen, Pauli; Tamminen, Johanna

    2017-04-01

    In this study we show the vertical distribution of atmospheric methane (CH4) measured in Sodankylä, Northern Finland. The CH4 profiles are retrieved from the direct Sun FTS measurements using the dimension reduction retrieval method. In the retrieval method, we have a few degrees of freedom about the profile shape. The data set covers years 2010-2016 (from February to November) and altitudes 0-40 km. The retrieved FTS profiles are validated against ACE satellite measurements and AirCore balloon measurements. The total columns derived from the FTS profiles are compared to the official TCCON XCH4 data. A vertically resolved methane data set can be used, e.g., to study stratospheric methane during the polar vortex.

  19. Methane Emission from Tropical Rivers

    NASA Astrophysics Data System (ADS)

    Sawakuchi, H. O.; Rasera, M. F. F. L.; Krusche, A. V.; Ballester, M. V. R.

    2012-04-01

    Inland water is already known as an important source of methane to atmosphere. Methane is produced in anaerobic environments usually find in lakes and floodplain bottom sediment. It is the main reason that almost all information regarding methane flux come from this environments. However, while floodplain dries during low water season reducing methanogenesis, rivers keep the capacity to emit methane throughout the year. Here we present preliminary results of CH4 flux measurements done in 6 large tropical rivers within the Amazon basin. We measured 17 areas using floating chamber during dry (low water) season, between September and November of 2011, in Amazon river mainstem, Araguaia, Xingu, Tapajós, Madeira, and Negro Rivers. Measured fluxes of all rivers ranged from 59.3 to 2974.4 mmol m-2 yr-1. Geomorphologic structure of channels is one important factor that contributes to this high heterogeneity due to development of low flow velocity depositional settings allowing formation of anoxic zones in rivers. Hydraulic and sediment barriers in the confluence of river channels promote the generation of natural dams which function as a trap for the suspension load favoring the deposition of organic rich muds. This kind of environment is very different from common river channels and has a stronger potential of methane emission. Average values of our flux measurements for this two river environments show that depositional areas can have much higher fluxes than the main channel, 1089.6 and 163.1 mmol m-2 yr-1, respectively. Hence, CH4 flux from these depositional zones is similar to some tropical floodplain lakes and reservoirs. Although the low flux from channel, the area covered by water is very large resulting in a significant contribution to the regional methane emission to the atmosphere. Moreover, mapping the area of these depositional river zones will give us a better idea of the magnitude of methane flux from tropical rivers.

  20. Biological control of trace metal and organometal benthic fluxes in a eutrophic lagoon (Thau Lagoon, Mediterranean Sea, France)

    NASA Astrophysics Data System (ADS)

    Point, D.; Monperrus, M.; Tessier, E.; Amouroux, D.; Chauvaud, L.; Thouzeau, G.; Jean, F.; Amice, E.; Grall, J.; Leynaert, A.; Clavier, J.; Donard, O. F. X.

    2007-04-01

    In situ benthic chamber experiments were conducted in the Thau Lagoon that allowed the simultaneous determination of the benthic exchanges of trace metals (Cd, Co, Cu, Mn, Pb and U) and mercury species (iHg and MMHg). Fluxes of organotin compounds (MBT, DBT and TBT) were also investigated for the first time. The benthic incubations were performed during two campaigns at four stations that presented different macrobenthic and macrophytic species distribution and abundance (see [Thouzeau, G., Grall, J., Clavier, J., Chauvaud, L., Jean, F., Leynaert, A., Longpuirt, S., Amice, E., Amouroux, D., 2007. Spatial and temporal variability of benthic biogeochemical fluxes associated with macrophytic and macrofaunal distributions in the Thau lagoon (France). Estuarine, Coastal and Shelf Science 72 (3), 432 446.]). The results indicate that most of the flux intensity as well as the temporal and spatial variability can be explained by the combined influence of microscale and macroscale processes. Microscale changes were identified using Mn flux as a good indicator of the redox conditions at the sediment water interface, and by extension, as an accurate proxy of benthic fluxes for most trace metals and mercury species. We also observed that the redox gradient at the interface is promoted by both microbial and macrobenthic species activity that governs O2 budgets. Macroscale processes have been investigated considering macrobenthic organisms activity (macrofauna and macroalgal cover). The density of such macroorganisms is able to explain most of the spatial and temporal variability of the benthic metal fluxes within a specific site. A tentative estimation of the flux of metals and organometals associated with deposit feeder and suspension feeder activity was found to be in the range of the flux determined within the chambers for most considered elements. Furthermore, a light/dark incubation investigating a dense macroalgal cover present at the sediment surface illustrates the role

  1. A quantification of the standing stock of macro-debris in Majuro lagoon and its effect on hard coral communities.

    PubMed

    Richards, Zoe T; Beger, Maria

    2011-08-01

    The accumulation of debris is an insidious problem throughout the world's oceans. Here we document 234.24 items of macro-debris/km2 in the shallow populated parts of Majuro lagoon (Republic of the Marshall Islands) which is the second highest standing stock of macro-debris recorded to date in any benthic marine habitat in the world. The majority of macro-debris was from household sources (78.7%) with the peak abundance recorded in areas of medium affluence. Marine debris causes suffocation, shading, tissue abrasion and mortality of corals and we show a significant negative correlation exists between the level of hard coral cover and coverage of marine debris. Given long decomposition times, even if the input of rubbish to Majuro lagoon is stopped immediately, the standing stock of debris will persist for centuries. Multiple new initiatives are needed to curtail the direct and indirect dumping of waste in Majuro lagoon.

  2. Assessing methane oxidation under landfill covers and its contribution to the above atmospheric CO₂ levels: the added value of the isotope (δ¹³C and δ¹⁸O CO₂; δ¹³C and δD CH₄) approach.

    PubMed

    Widory, D; Proust, E; Bellenfant, G; Bour, O

    2012-09-01

    We are presenting here a multi-isotope approach (δ¹³C and δ¹⁸O of CO₂; δ¹³C and δD of CH₄) to assess (i) the level(s) of methane oxidation during waste biodegradation and its migration through a landfill cover in Sonzay (France), and (ii) its contribution to the atmospheric CO₂ levels above the surface. The isotope approach is compared to the more conventional mass balance approach. Results from the two techniques are comparable and show that the CH₄ oxidation under the landfill cover is heterogenous, with low oxidation percentages in samples showing high biogas fluxes, which was expected in clay covers presenting fissures, through which CH₄ is rapidly transported. At shallow depth, more immobile biogas pockets show a higher level of CH₄ oxidation by the methanotrophic bacteria. δ¹³C of CO₂ samples taken at different heights (from below the cover up to 8m above the ground level) were also used to identify and assess the relative contributions of its main sources both under the landfill cover and in the surrounding atmosphere. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment

    SciTech Connect

    Martens, C.S.; Blair, N.E.; Green, C.D.; Des Marais, D.J.

    1986-09-19

    Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks. Values for the carbon isotope ratio (delta /sup 13/C) of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95%. The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen. The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites. 17 references, 2 figures, 2 tables.

  4. Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment

    NASA Technical Reports Server (NTRS)

    Martens, C. S.; Green, C. D.; Blair, N. E.; Des Marais, D. J.

    1986-01-01

    Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks. Values for the carbon isotope ratio of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95 percent. The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen. The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites.

  5. State-of-the-lagoon reports as vehicles of cross-disciplinary integration.

    PubMed

    Zaucha, Jacek; Davoudi, Simin; Slob, Adriaan; Bouma, Geiske; van Meerkerk, Ingmar; Oen, Amy Mp; Breedveld, Gijs D

    2016-10-01

    An integrative approach across disciplines is needed for sustainable lagoon and estuary management as identified by integrated coastal zone management. The ARCH research project (Architecture and roadmap to manage multiple pressures on lagoons) has taken initial steps to overcome the boundaries between disciplines and focus on cross-disciplinary integration by addressing the driving forces, challenges, and problems at various case study sites. A model was developed as a boundary-spanning activity to produce joint knowledge and understanding. The backbone of the model is formed by the interaction between the natural and human systems, including economy and governance-based subsystems. The model was used to create state-of-the-lagoon reports for 10 case study sites (lagoons and estuarine coastal areas), with a geographical distribution covering all major seas surrounding Europe. The reports functioned as boundary objects to build joint knowledge. The experiences related to the framing of the model and its subsequent implementation at the case study sites have resulted in key recommendations on how to address the challenges of cross-disciplinary work required for the proper management of complex social-ecological systems such as lagoons, estuarine areas, and other land-sea regions. Cross-disciplinary integration is initially resource intensive and time consuming; one should set aside the required resources and invest efforts at the forefront. It is crucial to create engagement among the group of researchers by focusing on a joint, appealing overall concept that will stimulate cross-sectoral thinking and focusing on the identified problems as a link between collected evidence and future management needs. Different methods for collecting evidence should be applied including both quantitative (jointly agreed indicators) and qualitative (narratives) information. Cross-disciplinary integration is facilitated by functional boundary objects. Integration offers important

  6. Epiphyte communities on Thalassia testudinum from Grand Cayman, British West Indies: Their composition, structure, and contribution to lagoonal sediments

    NASA Astrophysics Data System (ADS)

    Corlett, Hilary; Jones, Brian

    2007-02-01

    Thalassia testudinum, the most common seagrass found in lagoons around Grand Cayman, influences sedimentation by baffling currents, binding sediment on the seafloor, and providing substrates for a diverse epiphytic biota. About 85% of the epiphytic biota is formed of at least 3 species of coralline algae, 72 species of foraminifera, and 61 species of diatoms. The rest of the biota is formed of sponges, gastropods, ostracods, coccoliths, dinoflagellates, brown algae, and worms. The epiphytes are organized in three communities that are part of an organized tripartite community succession. The basal diatom community is overlain by the coralline algae community, which is then overlain by a community composed of a variety of taxa. The coralline algae community, which is the most extensive, typically covers ˜ 75% of the leaf's surface. Potentially, the skeletons of these epiphytes can make a significant contribution to the fine-grained sediment budget of these lagoons. Surprisingly, only a few of the epiphytes were found in the lagoonal sediment. It appears, therefore, that the epiphytes are lost through skeletal dissolution or transported out of the lagoon following storms. Irrespective of the cause, the epiphytes do not form a significant part of the lagoon sediment in Grand Cayman.

  7. Methane emissions from MBT landfills.

    PubMed

    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

  8. Seasonal Berm Behavior on a Coastal Lagoon Pocket Beach

    NASA Astrophysics Data System (ADS)

    Harden, L.

    2011-12-01

    Coastal lagoon beaches are typically characterized by a seasonal berm that separates the lagoon mouth from the open ocean during summer months and is temporarily breached and eroded offshore as a result of higher wave energy during winter months. Seasonal morphodynamic changes on a coastal lagoon pocket beach in Santa Cruz, California were monitored from August 2010 to April 2011. Monthly total station GPS surveys were conducted on Younger Lagoon Reserve beach in conjunction with monthly grain size analyses. A time series comparison of beach profiles extracted from shore-normal transects reveals that the berm fronting the lagoon mouth did not erode with increasing wave energy during the winter months as expected, but either stayed fixed while the foreshore steepened or migrated horizontally across shore. Berm height is likely maintained by wave overtopping of the berm crest at the lagoon mouth during high tides or storm events. Foreshore steepening occurs in conjunction with an increase in coarse sediment fraction and is consistent with increasing wave energy and turbulent swash interaction. Cross-shore sediment transport in the foreshore fronting the lagoon mouth is likely enhanced by infiltration and exfiltration of water on the shoreface due to the position of the water table with respect to the maximum swash runup. Coastal lagoon beach berm behavior and the subsequent extent of lagoon-ocean mixing has important implications for coastal water quality and lagoon ecosystem dynamics.

  9. Methane oxidation at a surface-sealed boreal landfill.

    PubMed

    Einola, Juha; Sormunen, Kai; Lensu, Anssi; Leiskallio, Antti; Ettala, Matti; Rintala, Jukka

    2009-07-01

    Methane oxidation was studied at a closed boreal landfill (area 3.9 ha, amount of deposited waste 200,000 tonnes) equipped with a passive gas collection and distribution system and a methane oxidative top soil cover integrated in a European Union landfill directive-compliant, multilayer final cover. Gas wells and distribution pipes with valves were installed to direct landfill gas through the water impermeable layer into the top soil cover. Mean methane emissions at the 25 measuring points at four measurement times (October 2005-June 2006) were 0.86-6.2 m(3) ha(-1) h(-1). Conservative estimates indicated that at least 25% of the methane flux entering the soil cover at the measuring points was oxidized in October and February, and at least 46% in June. At each measurement time, 1-3 points showed significantly higher methane fluxes into the soil cover (20-135 m(3) ha(-1) h(-1)) and methane emissions (6-135 m(3) ha(-1) h(-1)) compared to the other points (< 20 m(3) ha(-1) h(-1) and < 10 m(3) ha(-1) h(-1), respectively). These points of methane overload had a high impact on the mean methane oxidation at the measuring points, resulting in zero mean oxidation at one measurement time (November). However, it was found that by adjusting the valves in the gas distribution pipes the occurrence of methane overload can be to some extent moderated which may increase methane oxidation. Overall, the investigated landfill gas treatment concept may be a feasible option for reducing methane emissions at landfills where a water impermeable cover system is used.

  10. 40 CFR Table Jj-6 to Subpart Jj of... - Collection Efficiencies of Anaerobic Digesters

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Manure Management Pt. 98, Subpt. JJ... digester type Cover type Methane collection efficiency Covered anaerobic lagoon (biogas capture) Bank...

  11. 40 CFR Table Jj-6 to Subpart Jj of... - Collection Efficiencies of Anaerobic Digesters

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Manure Management Pt. 98, Subpt. JJ... digester type Cover type Methane collection efficiency Covered anaerobic lagoon (biogas capture) Bank...

  12. Cover Crops

    USDA-ARS?s Scientific Manuscript database

    Cover crops are a beneficial tool for use in conservation tillage systems. Cover crop residues reduce soil erosion from water and wind, increase soil water availability for subsequent crops, enhance soil organic matter and biological activity, and can decrease labor and energy inputs. Cover crop...

  13. Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades

    SciTech Connect

    Burke, R.A.; Barber, T.R.; Sackett, W.M. )

    1988-12-01

    Methane flux and the stable isotopic composition of sedimentary methane were measured at four locations in the Florida Everglades system. Individual estimates of methane flux ranged over more than 3 orders of magnitude, from about 0.001 to 2.6 g CH{sub 4}/sq m/day. Significant interstation differences in total methane flux were also observed and are judged most likely attributable to differences in the size and spacing of emergent aquatic vegetation, and possibly differences in the type of organic matter incorporated into the sediments. On the basis of measurements presented here and by other investigators, the Everglades system appears to be a relatively weak source of atmospheric methane, probably contributing less than 0.5 Tg CH{sub 4}/yr. Emergent aquatic plants appear to be capable of indirectly affecting the stable isotopic composition of sedimentary methane by stimulating methane oxidation via root aeration. A significant positive correlation between delta D-CH4 and delta C{sup 13}-CH{sub 4} was observed for samples collected from sediments covered by tall, dense stands of emergent plants. In contrast, a significant negative correlation between the delta D and delta C{sup 13} of sedimentary methane was observed for samples collected at an open water site where ebullition dominated methane transfer to the atmosphere. 63 refs., 8 figs., 3 tabs.

  14. Ship traffic and shoreline erosion in the Lagoon of Venice

    NASA Astrophysics Data System (ADS)

    Scarpa, Gian Marco; Zaggia, Luca; Lorenzetti, Giuliano; Manfè, Giorgia; Parnell, Kevin; Molinaroli, Emanuela; Rapaglia, John; Gionta, Sofia

    2016-04-01

    A study based on the analysis of a historical sequence of aerial photographs and satellite images combined with in situ measurements revealed an unprecedented shoreline regression on the side of a major waterway in the Venice Lagoon, Italy. The study considered long and short-term recession rates caused by ship-induced depression wakes in an area which was reclaimed at the end of the '60 for the expansion of the nearby Porto Marghera Industrial Zone and never used since then. The GIS analysis performed with the available imagery shows an average retreat of about 4 m yr-1 in the period between 1965 and 2015. Field measurements carried out between April 2014 and January 2015 also revealed that the shoreline's regression still proceed with a speed comparable to the long-term average regardless of the distance from the navigation channel and is not constant through time. Periods of high water levels determined by astronomical tide or storm surges, more common in the winter season, are characterized by faster regression rates. The retreat proceeds by collapse of slabs of the reclaimed muddy soil after erosion and removal of the underlying original salt marsh sediments and is a discontinuous process in time and space depending on morphology, intrinsic propertiesand vegetation cover of the artificial deposits. Digitalization of historical maps and new bathymetric surveys made in April 2015 allowed for the reconstruction of two digital terrain models for both past and present situations. The two models have been used to calculate the total volume of sediment lost during the period between 1970 and 2015. The results of this study shows as ship-channel interactions can dominate the morphodynamics of a waterway and its margins and permitted to better understand how this part of the Venice Lagoon reacted to the pressure of human activities in the post-industrial period. Evaluation of the temporal and spatial variation of shoreline position is also crucial to predict future

  15. Potential methane reservoirs beneath Antarctica.

    PubMed

    Wadham, J L; Arndt, S; Tulaczyk, S; Stibal, M; Tranter, M; Telling, J; Lis, G P; Lawson, E; Ridgwell, A; Dubnick, A; Sharp, M J; Anesio, A M; Butler, C E H

    2012-08-30

    Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14 kilometres thick and an estimated 21,000 petagrams (1 Pg equals 10(15) g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300 metres in West Antarctica and 700 metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage.

  16. Alterations in macroinvertebrate spatial patterns in coastal lagoons: Óbidos (NW coast of Portugal) 1984 versus 2002

    NASA Astrophysics Data System (ADS)

    Rodrigues, Ana Maria; Quintino, Victor; Pereira, Fábio; Freitas, Rosa

    2012-09-01

    The macroinvertebrate spatial distribution patterns in the Lagoon of Óbidos were studied in 1984 and revisited in 2002. The overall surficial sediments and benthic community patterns show consistent similarities in the two sampling periods, but also important differences. The lagoon is relatively shallow, with about 1/3 of the area covered with extensive intertidal sand banks. These are interrupted by a navigation channel bordering the northern margin (1984) and, following dredging operations, a new navigation channel was opened along the southern margin (2002). The sediments in the navigation channels were coarser and with less percentage of fines in 2002 than in 1984. Arthropods dominated the species richness and abundance in 1984, but were much less important in 2002, when the community was dominated by molluscs and annelids, both in species numbers as well as in abundance. In 1984, the structure of the macrofauna communities closely followed a general model proposed for Atlantic and Mediterranean lagoons, with the marine, the transition and the lagoon communities occupying very well defined areas. This gradient was in accordance with an increase in the fines and organic matter content directed inwards allowing for the coexistence of several characteristic lagoon species with others characteristic of organic enriched sediments. In 2002 this spatial pattern is still recognized but the marine and the transition communities are spatially mixed, occupying both the entrance region and the navigation channels, whereas the characteristic lagoon community identified in 1984 was only recognized in a group of sites located along the southern margin in 2002. Several species show very important changes in their distribution extent in the lagoon system. These changes essentially show a generalized inward expansion of the distribution range of the marine species, in agreement with a larger influence of marine conditions toward the inner areas of the lagoon. This study shows

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

    PubMed

    Scheutz, Charlotte; Kjeldsen, Peter; Bogner, Jean E; De Visscher, Alex; Gebert, Julia; Hilger, Helene A; Huber-Humer, Marion; Spokas, Kurt

    2009-08-01

    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 utilizing oxygen that diffuses into the cover layer from the atmosphere. The methane oxidation process, which is governed by several environmental factors, can be exploited in engineered systems developed for methane emission mitigation. Mathematical models that account for methane oxidation can be used 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.

  18. Methane flux and stable hydrogen and carbon isotope composition of sedimentary methane from the Florida Everglades

    NASA Astrophysics Data System (ADS)

    Burke, Roger A., Jr.; Barber, Timothy R.; Sackett, William M.

    1988-12-01

    Methane flux and the stable isotopic composition of sedimentary methane were measured at four locations in the Florida Everglades system. Individual estimates of methane flux ranged over more than 3 orders of magnitude, from about 0.001 to 2.6 g CH4 m-2 d-1. Significant interstation differences in total methane flux were also observed and are judged most likely attributable to differences in the size and spacing of emergent aquatic vegetation, and possibly differences in the type (i.e., vascular plant versus algal) of organic matter incorporated into the sediments. On the basis of measurements presented here and by other investigators, the Everglades system appears to be a relatively weak source of atmospheric methane, probably contributing less than 0.5 Tg CH4 yr-1. Emergent aquatic plants appear to be capable of indirectly affecting the stable isotopic composition of sedimentary methane by stimulating methane oxidation via root aeration. A significant positive correlation between δD-CH4 and δ13C-CH4 was observed for samples collected from sediments covered by tall, dense stands of emergent plants. In contrast, a significant negative correlation between the δD and δ13C of sedimentary methane was observed for samples collected at an open water site where ebullition dominated methane transfer to the atmosphere. The mean δ13C of sedimentary methane samples measured in the Everglades system (mean δ13C =-61.7‰, s.d. = 3.6‰, n = 51) is not significantly different from the estimated average δ13C of all natural sources (-58.3‰). The mean δD of Everglades sedimentary methane (mean δ D = -293‰, s.d. = 14‰, n = 50) appears to be slightly less D-depleted than the estimated average methane (δD =-360 ± 30‰) from all sources.

  19. Lagoons and oxidation ponds. [Wastewater treatment

    SciTech Connect

    George, D.B.

    1982-06-01

    A review of the literature on waste stabilization pond systems is presented. Factors such as wastewater temperature, and levels of heavy metals that affect the stability of the lagoons and oxidation ponds, and methods to upgrade stabilization pond effluent to meet state and federal effluent requirements are discussed. Model simulations utilized to predict the treatment efficiency of various waste stabilization pond geometries, and inlet and outlet configurations are reviewed. (KRM)

  20. Application of Potential Non-Point Pollution Index For An Urban Watershed: Istanbul, Kucukcekmece Lagoon

    NASA Astrophysics Data System (ADS)

    Musaoglu, N.; Dikerler, T.; Seker, D. Z.; Ustun, B.

    2011-12-01

    Istanbul is a major city with more than 15 million population and limited water resources. Besides, its urbanized area has been rapidly expanding for more than 30 years. Küçükçekmece Lagoon, as a potential RAMSAR site with its rich natural diversity and housing asset for birds, has been suffering from urbanization and industrial stress. With Sazlidere Dam constructed on the Lagoon's most important creek which supplies fresh water, Küçükçekmece Basin has almost 600 km2 wide area. Due to dam operation which cuts fresh water input down, water quality of the Küçükçekmece Lagoon has been deteriorating, as well as other antropogenic impacts. Potential non-point pollution index (or PNPI) is based on land use, soil and topographic data and aims to highlight the potentially polluting areas in a watershed. Denoting those areas, PNPI puts an assessment of the pressure exerted on the water bodies by different land uses. This index calculates different layers in order to represent run-off, land cover effect, and the distance of each polluting source (or pixels) in the study area. By the multiplication of those layers under GIS, a new data layer is produced showing the polluting potential of each pixel on the study area. For by Küçükçekmece Basin, Landsat ETM satellite images have been taken and its land use produced by unsupervised classification. Using this updated data, land use - land cover indicator has been calculated for the basin. Topography is another fact that is needed to produce both run-off indicator and distance indicator and it is generated by elevation data with 5m resolution. By integrating these indicator layers, PNPI analysis layer has been produced for Küçükçekmece Lagoon watershed.

  1. Methane: A Menace Surfaces

    NASA Astrophysics Data System (ADS)

    Anthony, Katey Walter

    2011-11-01

    The arctic permafrost is thawing, releasing organic matter that was frozen in the ground into the bottoms of lakes. This organic matter feeds microbes that produce methane, which in turn escapes to the atmosphere. Permafrost, a rich source of organic carbon, covers 20% of the earth's land surface, and one third to one half of permafrost is now within 1.0 ° C to 3 ° C of thawing. New estimates indicate that by 2100, thawing permafrost could boost emissions of methane—a greenhouse gas that's 25 times more potent than carbon dioxide—by 20 to 40 percent beyond what would be produced by all natural and man-made sources. As a result, the earth's mean annual temperature could rise by an additional 0.32 ° C, further upsetting weather patterns and sea level.

  2. Hydrological dynamics of water sources in a Mediterranean lagoon

    NASA Astrophysics Data System (ADS)

    Stumpp, C.; Ekdal, A.; Gönenc, I. E.; Maloszewski, P.

    2014-12-01

    Lagoons are important ecosystems occupying large coastal areas worldwide. Lagoons contain various mixtures of marine and freshwater sources which are highly dynamic in time. However, it often remains a challenge to identify and quantify dynamic changes of water sources, particularly in heterogeneous lagoon systems like the Köycegiz-Dalyan lagoon (KDL), which is located at the south-west of Turkey on the Mediterranean Sea coast. The objective of this study was to quantify different contributions of potential water sources i.e. surface water, groundwater and seawater in the lagoon and how these water sources changed over time and space. In the wet- and dry-season stable isotopes of water, chloride concentration (Cl-) and salinity were measured in two depths in the lagoon and surrounding water bodies (sea, lake, groundwater). Different components of water sources were quantified with a three component endmember mixing analysis. Differences in Cl- and stable isotopes over time indicated the dynamic behaviour of the system. Generally, none of the groundwater samples was impacted by water of the Mediterranean Sea. During the wet season, most of the lagoon water (> 95%) was influenced by freshwater and vertically well mixed. During the dry season, high Cl- in the deeper sampling locations indicated a high contribution of marine water throughout the entire lagoon system due to saltwater intrusion. However, a distinct layering in the lagoon was obvious from low Cl- and depleted isotope contents close to the surface supporting freshwater inflow into the system even during the dry season. Besides temporal dynamics also spatial heterogeneities were identified. Changes in water sources were most evident in the main lagoon channel compared to more isolate lagoon lakes, which were influenced by marine water even in the wet season, and compared to side branches indicating slower turnover times. We found that environmental tracers helped to quantify highly dynamic and

  3. Computing the residence times in the Venice Lagoon

    NASA Astrophysics Data System (ADS)

    Umgiesser, G.; Cucco, A.

    2003-04-01

    The Venice Lagoon is a shallow water body with a total area of about 500 km2. Three inlets govern the water exchanges between the Adriatic Sea and the Venice Lagoon. Water, entering and exiting through these channels during an entire tidal cycle, changes its biogeochemical and physical properties. The aim of this work is to investigate the Venice Lagoon circulation and to quantify the turn over time of the lagoon which mainly influences the water quality of the basin. The study has been carried out with a numerical model. The model computes the main hydrodynamic unknowns on a spatial domain that represents the Venice Lagoon and the Adriatic Sea with a finite element grid. The model considers as open boundary the line of Otranto channel in the southern Adriatic Sea and elsewhere as closed boundary the whole perimeter of the Adriatic Sea and Venice Lagoon. The model has been calibrated using the sea level data measured by more than twelve tide gauges located along the Adriatic Sea and inside the lagoon. The results obtained by the calibrated model have been validated with experimental data such as discharge data collected by botton mounted ADCP probes located at each inlet. The simulations take into account the tidal forcing and the different wind regimes. The instantaneous circulation and the residual current fields have been analyzed and the impact of the most important wind regimes on the circulation has been studied. The turn over time of the lagoon has been computed under different forcing conditions. A passive tracer only subjected to transport mechanism, has been released inside the lagoon. Resolving the time decaying of the tracer concentration for the whole area, the model computes the spatial distribution of the residence time in the basin. The results show that the re-import of water that previously exited the lagoon through the three inlets, plays an important role on the estimation of the turn over time of the lagoon thus influencing the water quality of

  4. Atmospheric Simulation of Time-Dependent Landfill Methane Emissions

    NASA Astrophysics Data System (ADS)

    Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

    2016-12-01

    Landfill methane emissions are difficult to estimate due to limited observations and data uncertainty. A surface flux drag law for landfill methane emissions is added to the Weather Research and Forecasting model (WRF) to predict emissions based on soil and atmospheric methane concentrations and horizontal wind speed, based on similar surface flux equations used by WRF for heat and moisture. Simulations of landfill methane emissions and the tracer dilution method used to estimate landfill methane emissions are run over different time periods for Sandtown Landfill in Delaware, USA. Two questions are explored through analysis of the simulations: how does the accuracy of the tracer dilution method change over the course of the day, and how do variations in wind speed affect the variability of landfill methane emissions on short time scales (a few hours). Models and observations show that soil methane concentration does not change significantly on small time scales, so variability in emissions over a one to two hour measurement period can be attributed to variations in wind speed. The values used for soil methane concentration in the daily cover and intermediate cover are taken from the California Landfill Methane Inventory Model (CALMIM), which is used to simulate soil processes and predict soil methane concentrations for Sandtown Landfill.

  5. Spatial and temporal variability of benthic biogeochemical fluxes associated with macrophytic and macrofaunal distributions in the Thau lagoon (France)

    NASA Astrophysics Data System (ADS)

    Thouzeau, Gérard; Grall, Jacques; Clavier, Jacques; Chauvaud, Laurent; Jean, Frédéric; Leynaert, Aude; ni Longphuirt, Sorcha; Amice, Erwan; Amouroux, David

    2007-04-01

    The aim of the present study in the Thau lagoon was to determine spatial and temporal variations of biogeochemical fluxes at the sediment-water interface (oxygen, nutrients and DIC) associated with macrophytic and/or macrofaunal distributions during spring time, which is a period of major vegetal growth. The pattern of benthic fluxes was studied in April 2002 and May 2003 for four main benthic biota of the lagoon, with one site subject to biodeposition by oysters cultured in suspension, one site representative of the central part of the lagoon that was only under general sedimentation, one site densely covered by macroalgae and one site located within a seagrass meadow. The results emphasize the role of oyster cultures on benthic fluxes and the impact of spatial heterogeneity of the benthos (macrophytes and macrofauna) distribution at various spatial scales. Hypoxic conditions were shown to develop at the sediment-water interface in May 2003 in the central part of the lagoon. Oxygen and DIC fluxes emphasized benthic respiration overall, and spatio-temporal variability mainly due to the presence/absence of the macroalgal cover on the sediment. The absence of benthic macroinfaunal organisms in the stations under the influence of oyster biodeposition and facing a dense macroalgal cover highlighted anoxic conditions in the sediments. Major benthic macrofauna community changes were observed in the central zone between April 2002 and May 2003, emphasizing sediment organic matter enrichment. The analysis of benthic fluxes over a productive period of the annual cycle provided a basis for describing spatial and temporal variations of the dynamics of sediment-water exchanges in the lagoon.

  6. Patterns of seasonal variation in lagoonal macrozoobenthic assemblages (Mellah lagoon, Algeria).

    PubMed

    Magni, Paolo; Draredja, Brahim; Melouah, Khalil; Como, Serena

    2015-08-01

    In coastal lagoons, many studies indicated that macrozoobenthic assemblages undergo marked temporal fluctuations as related to the strong environmental variability of these systems. However, most of these studies have not assessed the seasonal patterns of these fluctuations and none of them has investigated the consistency of this variation in different areas within the same lagoon system. In this study, we assessed patterns of variation at multiple temporal (date, season and year) scales in two different areas in the coastal lagoon of Mellah (northeast Algeria). These areas (hereafter Shore and Center) are representative of two different environments typically found in coastal lagoons. The Shore (water depth of about 1.5-2 m) is characterized by relatively higher hydrodynamics, sand to silty-sand sediments and the presence of vegetation (Ruppia maritima), the Center (water depth of about 3-3.5 m) is characterized by mud to sandy-mud, organic-enriched sediments due to fine particle accumulation. Results showed two distinct patterns of seasonal variation in Shore and Center assemblages for two consecutive years. In Shore, species richness (S), total abundance (N) and the abundance of several dominant taxa were highest in summer and/or autumn. This pattern can be related to the local environmental conditions maintaining relatively well oxidized conditions, while increasing food availability, and favoring the recruitment of species and individuals in summer/autumn. On the contrary in Center, S was lowest in summer and autumn, and N and the abundance of fewer dominant taxa were lowest in summer. In Center, the bivalve Loripes lucinalis showed a 10-fold increase from summer to autumn in both years, likely related to the lagoon's hydrodynamics favoring larval transport and settlement in the central sector of the lagoon. Overall, the seasonal variation found in Center followed a regression/recovery pattern typical of opportunistic assemblages occurring in confined

  7. Superfund explanation of significant difference for the record of decision (EPA Region 1): Iron Horse Park, Operable Unit 1, Boston/Marine Wastewater Lagoons, Billerica, MA, October 1, 1997

    SciTech Connect

    1999-03-01

    The September 15, 1988 Record of Decision (ROD) (PB89-206247) called for treatment of contaminated soil and sludge from the lagoons by bioremediation, returning the treated material to the lagoon area, covering it with clean soil and establishing a vegetative cover. The ROD also required decontamination and disposal of piping and pumps associated with the lagoons. Due to the lack of success of bioremediation, alternative remedial alternatives evaluated during the June 1988 Feasibility Study (FS) of B and M Lagoons were reinvestigated. Asphalt batching has become an accepted treatment technology that can be used to produce a cleanup that is more cost effective than the on-site stabilization option considered in the FS. This technology would result in off-site treatment and reuse which eliminates the need to utilize a costly on-site cap over the concrete-stabilized material.

  8. Coastal Evolution in a Mediterranean Microtidal Zone: Mid to Late Holocene Natural Dynamics and Human Management of the Castelló Lagoon, NE Spain

    PubMed Central

    Ejarque, Ana; Julià, Ramon; Reed, Jane M.; Mesquita-Joanes, Francesc; Marco-Barba, Javier; Riera, Santiago

    2016-01-01

    We present a palaeoenvironmental study of the Castelló lagoon (NE Spain), an important archive for understanding long-term interactions between dynamic littoral ecosystems and human management. Combining geochemistry, mineralogy, ostracods, diatoms, pollen, non-pollen palynomorphs, charcoal and archaeo-historical datasets we reconstruct: 1) the transition of the lagoon from a marine to a marginal environment between ~3150 cal BC to the 17th century AD; 2) fluctuations in salinity; and 3) natural and anthropogenic forces contributing to these changes. From the Late Neolithic to the Medieval period the lagoon ecosystem was driven by changing marine influence and the land was mainly exploited for grazing, with little evidence for impact on the natural woodland. Land-use exploitation adapted to natural coastal dynamics, with maximum marine flooding hampering agropastoral activities between ~1550 and ~150 cal BC. In contrast, societies actively controlled the lagoon dynamics and become a major agent of landscape transformation after the Medieval period. The removal of littoral woodlands after the 8th century was followed by the expansion of agrarian and industrial activities. Regional mining and smelting activities polluted the lagoon with heavy metals from the ~11th century onwards. The expansion of the milling industry and of agricultural lands led to the channelization of the river Muga into the lagoon after ~1250 cal AD. This caused its transformation into a freshwater lake, increased nutrient load, and the infilling and drainage of a great part of the lagoon. By tracking the shift towards an anthropogenically-controlled system around ~750 yr ago, this study points out Mediterranean lagoons as ancient and heavily-modified systems, with anthropogenic impacts and controls covering multi-centennial and even millennial timescales. Finally, we contributed to the future construction of reliable seashell-based chronologies in NE Spain by calibrating the Banyuls-sur-Mer

  9. Coastal Evolution in a Mediterranean Microtidal Zone: Mid to Late Holocene Natural Dynamics and Human Management of the Castelló Lagoon, NE Spain.

    PubMed

    Ejarque, Ana; Julià, Ramon; Reed, Jane M; Mesquita-Joanes, Francesc; Marco-Barba, Javier; Riera, Santiago

    2016-01-01

    We present a palaeoenvironmental study of the Castelló lagoon (NE Spain), an important archive for understanding long-term interactions between dynamic littoral ecosystems and human management. Combining geochemistry, mineralogy, ostracods, diatoms, pollen, non-pollen palynomorphs, charcoal and archaeo-historical datasets we reconstruct: 1) the transition of the lagoon from a marine to a marginal environment between ~3150 cal BC to the 17th century AD; 2) fluctuations in salinity; and 3) natural and anthropogenic forces contributing to these changes. From the Late Neolithic to the Medieval period the lagoon ecosystem was driven by changing marine influence and the land was mainly exploited for grazing, with little evidence for impact on the natural woodland. Land-use exploitation adapted to natural coastal dynamics, with maximum marine flooding hampering agropastoral activities between ~1550 and ~150 cal BC. In contrast, societies actively controlled the lagoon dynamics and become a major agent of landscape transformation after the Medieval period. The removal of littoral woodlands after the 8th century was followed by the expansion of agrarian and industrial activities. Regional mining and smelting activities polluted the lagoon with heavy metals from the ~11th century onwards. The expansion of the milling industry and of agricultural lands led to the channelization of the river Muga into the lagoon after ~1250 cal AD. This caused its transformation into a freshwater lake, increased nutrient load, and the infilling and drainage of a great part of the lagoon. By tracking the shift towards an anthropogenically-controlled system around ~750 yr ago, this study points out Mediterranean lagoons as ancient and heavily-modified systems, with anthropogenic impacts and controls covering multi-centennial and even millennial timescales. Finally, we contributed to the future construction of reliable seashell-based chronologies in NE Spain by calibrating the Banyuls-sur-Mer

  10. Liquid Ethane and Methane on Titan

    NASA Astrophysics Data System (ADS)

    Clark, Roger Nelson; Curchin, J.; Brown, R. H.; Barnes, J. W.; Jaumann, R.; Soderblom, L.; Cruikshank, D. P.; Lunine, J.; Stephan, K.; Hoefen, T. H.; Le Mouelic, S.; Sotin, C.; Baines, K.; Buratti, B.; Nicholson, P.

    2008-09-01

    Absorption coefficients for liquid methane and ethane were derived in a 1-bar nitrogen atmosphere at 90K. Ethane and methane were condensed in an aluminum sample cup, and a 2-way transmission spectrum was measured. Different path lengths up to 14 mm allowed a wide range of absorption coefficients to be measured, and covered the range needed to compare to spectra of Titan in the 1- to 5-micron atmospheric windows. The data were used to compute possible liquid absorption in spectra from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) and were compared to global VIMS data for Titan. The laboratory data show that both liquid methane and ethane have a strong absorption band near 4.97 microns that is detectable by VIMS. A liquid lake thickness of 3 mm (6 mm path length) would result in an absorption band depth of about 65% for methane and 85% for ethane. Ethane has a 2.02-micron absorption with a strength similar to the 4.97-micron absorption, and methane has an absorption that is 10x weaker. Continuum absorption would result in the following surface reflectance levels (at VIMS wavelengths and resolution). Examining VIMS Titan data, we find that for most of the surface, we detect no liquid methane or ethane. In a few locations VIMS data indicate liquid methane or ethane, but at less than about 1-mm total path length.

  11. Lagoon Seepage Testing Report for Central Facilities Area (CFA) Sewage Lagoons at Idaho National Laboratory, Butte County, Idaho

    SciTech Connect

    Morrison, Bridger

    2014-09-01

    J-U-B ENGINEERS, Inc. (J-U-B) performed seepage tests on the CFA Wastewater Lagoons 1, 2, and 3 between August 26th and September 22nd, 2014. The lagoons were tested to satisfy the Idaho Department of Environmental Quality (DEQ) Rules (IDAPA 58.01.16) that require all lagoons be tested at a frequency of every 10 years and the Compliance Activity CA-141-03 in the DEQ Wastewater Reuse Permit for the CFA Sewage Treatment Plant (LA-000141-03). The lagoons were tested to determine if the average seepage rates are less than 0.25 in/day, the maximum seepage rate allowed for lagoons built prior to April 15, 2007. The average seepage rates were estimated for each lagoon and are given in Table-ES1. The average seepage rates for Lagoons 1 and 2 are less than the allowable seepage rate of 0.25 in/day. Lagoon 1 and 2 passed the seepage test and will not have to be tested again until the year 20241. However, the average seepage rate for Lagoon 3 appears to exceed the allowable seepage rate of 0.25 in/day which means the potential source for the excessive leakage should be investigated further.

  12. High-resolution seismic imaging of gas accumulations and seepage in the sediments of the Ria de Aveiro barrier lagoon (Portugal)

    NASA Astrophysics Data System (ADS)

    Duarte, Henrique; Menezes Pinheiro, Luis; Curado Teixeira, Francisco; Monteiro, José Hipólito

    2007-06-01

    Methane is a powerful greenhouse gas and an important energy source. The global significance and impact in coastal zones of methane gas accumulation and seepage in sediments from coastal lagoon environments are still largely unknown. This paper presents results from four high-resolution seismic surveys carried out in the Ria de Aveiro barrier lagoon (Portugal) in 1999, 2002 and 2003. These comprise three chirp surveys (RIAV99, RIAV02, RIAV02A) and one boomer survey (RIAV03). Evidence of extensive gas accumulation and seepage in tidal channel sediments from the Ria de Aveiro barrier lagoon is presented here for the first time. This evidence includes: acoustic turbidity, enhanced reflections, acoustic blanking, domes, and acoustic plumes in the water column (flares). The stratigraphy and structural framework control the distribution and extent of gas accumulations and seepage in the study area. In these shallow systems, however, tidal altitude variations have a significant impact on gas detection using acoustic methods, by changing the raw amplitude of the enhanced seismic reflections, acoustic turbidity, and acoustic blanking in gas-prone areas. Direct evidence of gas escape from drill holes in the surrounding area has shown that the gas present in the Ria de Aveiro consists of biogenic methane. Most of the gas in the study area was probably generated mainly in Holocene lagoon sediments. Evidence of faults affecting the Mesozoic limestones and clays underlying some of the shallow gas occurrences, and the presence of high-amplitude reflections in these deeper units raise the possibility that some of this gas could have been generated in deeper sedimentary layers, and then migrated upward through the fractured Mesozoic strata.

  13. Covering Crime.

    ERIC Educational Resources Information Center

    Gest, Ted; Krajicek, David; Hackney, Suzette; Moore, Melissa

    2003-01-01

    Presents four brief articles on covering crime. Notes that reporting on crimes requires special skills for student reporters, editors, and photographers. Explains how to gain access to scenes, to develop journalistic ethics, and how to cover crime and its victims. Discusses the relation of race and ethnic issues to crime, and how visual…

  14. Cryolava flow destabilization of crustal methane clathrate hydrate on Titan

    NASA Astrophysics Data System (ADS)

    Davies, Ashley Gerard; Sotin, Christophe; Choukroun, Mathieu; Matson, Dennis L.; Johnson, Torrence V.

    2016-08-01

    To date, there has been no conclusive observation of ongoing endogenous volcanic activity on Saturn's moon Titan. However, with time, Titan's atmospheric methane is lost and must be replenished. We have modeled one possible mechanism for the replenishment of Titan's methane loss. Cryolavas can supply enough heat to release large amounts of methane from methane clathrate hydrates (MCH). The volume of methane released is controlled by the flow thickness and its areal extent. The depth of the destabilisation layer is typically ≈30% of the thickness of the lava flow (≈3 m for a 10-m thick flow). For this flow example, a maximum of 372 kg of methane is released per m2 of flow area. Such an event would release methane for nearly a year. One or two events per year covering ∼20 km2 would be sufficient to resupply atmospheric methane. A much larger effusive event covering an area of ≈9000 km2 with flows 200 m thick would release enough methane to sustain current methane concentrations for 10,000 years. The minimum size of "cryo-flows" sufficient to maintain the current atmospheric methane is small enough that their detection with current instruments (e.g., Cassini) could be challenging. We do not suggest that Titan's original atmosphere was generated by this mechanism. It is unlikely that small-scale surface MCH destabilisation is solely responsible for long-term (> a few Myr) sustenance of Titan's atmospheric methane, but rather we present it as a possible contributor to Titan's past and current atmospheric methane.

  15. Methane Plumes on Mars

    NASA Image and Video Library

    Spectrometer instruments attached to several telescopes detect plumes of methane emitted from Mars during its summer and spring seasons. High levels of methane are indicated by warmer colors. The m...

  16. Water Hyacinths for Upgrading Sewage Lagoons to Meet Advanced Wastewater Treatment Standards, Part 1

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Water hyacinths, Eichhornia crassipes Mart. Solms, have demonstrated the ability to function as an efficient and inexpensive final filtration system in a secondary domestic sewage lagoon during a three month test period. These plants reduced the suspended solids, biochemical oxygen demanding substances, and other chemical parameters to levels below the standards set by the state pollution control agency. The water hyacinth-covered secondary lagoon utilized in this experiment had a surface area of 0.28 hectare (0.70 acre) with a total capacity of 6.8 million liters (1.5 million gallons), receiving an inflow of 522,100 liters (115,000 gallons) per day from a 1.1 hectare (3.8 acre) aerated primary sewage lagoon. These conditions allowed a retention time of 14 to 21 days depending on the water hyacinth evapotranspiration rates. The desired purity of final sewage effluent can be controlled by the water hyacinth surface area, harvest rate, and the retention time.

  17. Hydromorphic to subaqueous soils transitions in the central Grado lagoon (Northern Adriatic Sea, Italy)

    NASA Astrophysics Data System (ADS)

    Vittori Antisari, Livia; De Nobili, Maria; Ferronato, Chiara; Natale, Marco; Pellegrini, Elisa; Vianello, Gilmo

    2016-05-01

    The Grado lagoon is among the largest in the Mediterranean sea and is characterized by salt marshes, where tides influenced the development of a complex micromorphology coupled to a micromosaic of vegetation covers. This study represents the first contribution to the understanding of the main processes governing formation, development and spatial transitions between hydromorphic and subaqueous soils in an Adriatic lagoon ecosystem. Physicochemical characteristics and development of soils were investigated in three salt marshes differing for their proximity to the open sea, textural composition and age of formation. Soils of back barrier salt marshes had A/C profiles and were mostly characterized by a sandy coarse texture that allows rapid drainage and subsurface oxygen exchanges. Soil sequences from the inner salt marsh to its submerged border slope or to a brackish waterhole do not simply represent a hydrosequence, but also reflect erosion/sorting/accumulation processes. The soils in the central part of the lagoon have finer texture and in displayed transition or cambic horizons. Silty clay loam textures and low positions allowed the development of more severe anoxic conditions and accumulation of sulphides. The tide oscillation strongly contributed to formation of redoximorphic features, intensity of anaerobic conditions but also colonization by different plant communities. Discriminant analysis was performed to identify physicochemical properties which discriminate the different soils according to geo-morphological position and prevailing plants. It confirmed that differentiation of plant communities occurred according to distinct morphological and physicochemical soil properties, but also acted as a primary affecting factor of pedogenesis.

  18. Habitat distribution model for European flounder juveniles in the Venice lagoon

    NASA Astrophysics Data System (ADS)

    Zucchetta, Matteo; Franco, Anita; Torricelli, Patrizia; Franzoi, Piero

    2010-07-01

    In order to identify nursery habitats for Platichthys flesus in the Venice lagoon we developed a generalized additive model relating juvenile flounder's distribution to environmental variables. A field survey was conducted between March 2004 and June 2005 and between February and October 2008 in the central and Northern sub-basins of the lagoon. Each station was sampled by means of a beach seine net and characterized collecting the main chemico-physical variables, such as water temperature, salinity, turbidity, dissolved oxygen content and bottom grain size. Main winds fetches were also considered, and estimated in a GIS environment. A logistic model was fitted, and evaluated on an independent dataset. The response curves allowed to identify the role of the environmental parameters in explaining the distribution of the juvenile flounder: turbidity, salinity and sand content revealed to be the most important factors, showing the preference for mesohaline turbid waters together with a low sand content of the sediment. The application of this model to continuous surfaces of the environmental variables allowed the creation of potential habitat distribution maps. In this way it has been possible to recognize several areas covering a key role for the juveniles of flounder, located mainly in the inner part of the lagoon.

  19. Are coastal lagoons physically or biologically controlled ecosystems? Revisiting r vs. K strategies in coastal lagoons and estuaries

    NASA Astrophysics Data System (ADS)

    Pérez-Ruzafa, Angel; Marcos, Concepción; Pérez-Ruzafa, Isabel María; Pérez-Marcos, María

    2013-11-01

    Environmental stress influences biological assemblages, with species responding to stress by adopting particular life-history strategies (e.g., r vs. K). Coastal lagoons and estuaries are considered naturally stressed and physically controlled systems with frequent environmental disturbances and fluctuations. At the same time, their transitional nature (between terrestrial, freshwater and marine) makes them especially vulnerable to human impacts and land and freshwater inputs. As a result, it is hypothesised that residents of coastal lagoons would display characteristics of r-selected species. The r-strategy involves increased reproductive effort through early reproduction, small and numerous offspring with a large dispersive capability, short lifespan and small adult body size. Together, these traits provide a selective advantage in such unpredictable or short-lived environments. Alternatively, immigrants to coastal lagoons should mostly be K-strategists, with a competitive advantage over the r-strategists, at least on a temporary time scale. These hypotheses were explored using a dataset from 73 Atlanto-Mediterranean sites: 27 estuaries, 42 coastal lagoons and 4 from the sea, obtained from published sources. A detailed analysis of the distributions of the different resident fish species according to lagoon characteristics indicated that in lagoons with a higher marine influence the families Gobiidae, Blenniidae and Syngnathidae were common, while lagoons with freshwater influence are characterized by Cyprinidae and other freshwater species. In analyzing the biological strategies of lagoon species we found that fish assemblages inhabiting marine influenced lagoons were characterized by solitary, necto-benthonic sedentary species. These species are often hermaphroditic, with benthic broods and many exhibit brooding behaviour. This suggests that marine influenced lagoons are dominated by K-strategist species, while r-strategy species will be more common in

  20. Submarine groundwater discharge into typical tropical lagoons: A case study in eastern Hainan Island, China

    NASA Astrophysics Data System (ADS)

    Wang, Xilong; Du, Jinzhou

    2016-11-01

    Assessing submarine groundwater discharge (SGD) into lagoons and bays can be helpful to understand biogeochemical processes, especially nutrient dynamics. In the present paper, radium (Ra) isotopes were used to quantify SGD in two typical tropical lagoons (Laoye Lagoon (LY Lagoon) and Xiaohai Lagoon (XH Lagoon)) of eastern Hainan Island, China. The Ra mass balance model provided evidence that SGD plays an important role in the hydrology of the LY Lagoon and the XH Lagoon, delivering average SGD fluxes of 1.7 × 106 (94 L m-2 d-1) and 1.8 × 106 (41 L m-2 d-1) m3 d-1, respectively. Tidal pumping was one of the important driving forces for SGD fluxes in the LY and the XH Lagoons. Tidal-driven SGD into the tidal channels of both lagoons can account for approximately 10% of the total SGD flux into the lagoons. In addition, the dissolved inorganic nutrient budgets were reassessed in the LY Lagoon and the XH Lagoon, which showed that SGD was the major source of nutrients entering the LY Lagoon and that the LY Lagoon behaved as a source for dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) and as a sink for dissolved silicate (DSi). Nutrient loads in the XH Lagoon were mainly derived from riverine inputs and SGD, and the XH Lagoon behaved as a source for DIP, but a sink for DIN and DSi.

  1. Heat pipe methanator

    DOEpatents

    Ranken, William A.; Kemme, Joseph E.

    1976-07-27

    A heat pipe methanator for converting coal gas to methane. Gravity return heat pipes are employed to remove the heat of reaction from the methanation promoting catalyst, transmitting a portion of this heat to an incoming gas pre-heat section and delivering the remainder to a steam generating heat exchanger.

  2. Environmental enhancement of swine lagoons through influent treatment

    USDA-ARS?s Scientific Manuscript database

    Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. Failure of these lagoons during tropical storms in North Carolina along with major public environmental concerns led to a permanent state moratorium of construction of new anaerobic lag...

  3. Hubble reveals heart of Lagoon Nebula

    NASA Image and Video Library

    2017-09-27

    Image release date September 22, 2010 To view a video of this image go here: www.flickr.com/photos/gsfc/5014452203 Caption: A spectacular new NASA/ESA Hubble Space Telescope image reveals the heart of the Lagoon Nebula. Seen as a massive cloud of glowing dust and gas, bombarded by the energetic radiation of new stars, this placid name hides a dramatic reality. The Advanced Camera for Surveys (ACS) on the NASA/ESA Hubble Space Telescope has captured a dramatic view of gas and dust sculpted by intense radiation from hot young stars deep in the heart of the Lagoon Nebula (Messier 8). This spectacular object is named after the wide, lagoon-shaped dust lane that crosses the glowing gas of the nebula. This structure is prominent in wide-field images, but cannot be seen in this close-up. However the strange billowing shapes and sandy texture visible in this image make the Lagoon Nebula’s watery name eerily appropriate from this viewpoint too. Located four to five thousand light-years away, in the constellation of Sagittarius (the Archer), Messier 8 is a huge region of star birth that stretches across one hundred light-years. Clouds of hydrogen gas are slowly collapsing to form new stars, whose bright ultraviolet rays then light up the surrounding gas in a distinctive shade of red. The wispy tendrils and beach-like features of the nebula are not caused by the ebb and flow of tides, but rather by ultraviolet radiation’s ability to erode and disperse the gas and dust into the distinctive shapes that we see. In recent years astronomers probing the secrets of the Lagoon Nebula have found the first unambiguous proof that star formation by accretion of matter from the gas cloud is ongoing in this region. Young stars that are still surrounded by an accretion disc occasionally shoot out long tendrils of matter from their poles. Several examples of these jets, known as Herbig-Haro objects, have been found in this nebula in the last five years, providing strong support for

  4. Mid-late Holocene climate and ecology reconstruction around the Lagoon Mae-ho, East Korea based on diatom assemblage

    NASA Astrophysics Data System (ADS)

    Katsuki, K.; Lim, J.; Nahm, W.; Nakanishi, T.

    2012-12-01

    Diatom assemblage analysis in core sediment samples, PMR-2, from around Lagoon Mae-ho was examined for the purpose of evaluating the climate and local ecosystem change during the mid-late Holocene. Core PMR-2 is approximately 11 m length core, which was obtained from a front of reclaimed land around Lagoon Mae-ho in northeastern coast of Korea. Except for the top 2.5 m, preserved condition of diatom remain was well throughout the core. Radiocarbon ages were measured by a 1MV AMS facility at KIGAM. In particularly, high diatom remains were contained in obvious lamina layer between 7.0-9.5 m depth. Based on the diatom assemblage analysis, core PMR-2 was probably located under the small channel before 5,800 cal yr BP, which was under the lamina layer. Diatom assemblage was composed by the fresh and brackish taxa at that layer. Eutrophic lagoon was formed along the sea level increasing about 5,800 cal yr BP. Since 5,800 cal yr BP, location of core PMR-2 was covered by lagoon condition. Dominant taxa were eutrophic brackish diatom such as Cyclotella caspia and Cyclotella striata. Obvious lamina layer was composed under this condition. Since 4,000 cal yr BP, water exchange rate between the sea and paleo-lagoon Mae-ho was increased. This was indicated by the increasing marine-brackish diatom taxa. Anoxic bottom condition of the paleo-lagoon Mae-ho was resolved due to the increasing sea water inflow, and lamina layer was disappeared. After then, water depth of lagoon Mae-ho had become shallow gradually. Coring site was located around coastal marsh, and finally the site was reclaimed by human activity in recent. As mention above, obvious lamina was composed under the eutropic lagoon condition between 4,000 and 5,800 cal yr BP (7.0-9.5 m depth). These lamina were annual layers, was set of spring diatom bloom layer and other season's layer. In this presentation, we will discuss not only late to mid Holocene environmental change, but also discuss the short term climate

  5. Satellite Images Analysis of Temporal Change (1979-2000) of the Mangrove Covertures that Surround the Mandinga Coastal Lagoon, Mexico.

    NASA Astrophysics Data System (ADS)

    Aldeco-Ramírez, J.; Cervantes-Candelas, A.

    2007-05-01

    Knowledge about the historical condition of the resources and the risk of natural hazards is an urgent necessity in developing countries. Satellite images analysis was applied in this study in order to evaluate coverture changes between 1979 and 2000. Mangroves cover large areas of coastal lagoon shoreline in the tropics and subtropics where they are important components in the productivity and integrity of their ecosystems. Visual and digital analysis of satellite images have been applied since the seventies when the first Land sat satellite was put in orbit. The digital analysis technique is mainly based on the reflectance or spectral response of the different objects laid on the earth surface as captured by the satellite. The results are useful for the environmental assessment of natural resources as forest and crops, and the quantification of hazards as fires, plagues, deforestation and urban expansion. This research surveys satellite images from the Mandinga Lagoon System, a coastal lagoon located to the south of the main port of Veracruz (19.1N, 96.1W), during three periods: 1989 1999 and 2000. The mangrove foliar cover was analyzed throughout the time. The reflectance signal of the mangrove that encircles the lagoon was taken as a base line for reference. The normalized difference vegetation index (NDVI) was computed in order to classify the vegetal coverage along the time. From our analysis we obtained that from 1979 to 1990 and from 1990 to 2000 areas of 122 hectares (approx. 305 acres) and 202 hectares (approx. 505 acres) were lost, respectively. The rates of mangrove trimming of 11.1 and 20.2 hectares yr-1 are high compared with other coastal lagoons of Mexico. The main causes of this deforestation are also discussed along with other factors as, the change of use of land and the fishery declination.

  6. Lagoons and Reefs of New Caledonia

    NASA Image and Video Library

    2017-09-27

    NASA image acquired May 10, 2001 In July 2008, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) added 27 new areas to its list of World Heritage sites. One of those areas included the lagoons of New Caledonia. Some 1,200 kilometers (750 miles) east of Australia, this French-governed archipelago contains the world’s third-largest coral reef structure. The coral reefs enclose the waters near the islands in shallow lagoons of impressive biodiversity. On May 10, 2001, the Enhanced Thematic Mapper Plus on NASA’s Landsat 7 satellite captured this image of Île Balabio, off the northern tip of Grande Terra, New Caledonia’s main island. In this natural-color image, the islands appear in shades of green and brown—mixtures of vegetation and bare ground. The surrounding waters range in color from pale aquamarine to deep blue, and the color differences result from varying depths. Over coral reef ridges and sand bars, the water is shallowest and palest in color. Darker shades of blue characterize deeper waters. Reef-enclosed, shallow waters surround Île Balabio, and a larger, semi-enclosed lagoon appears immediately east of that island. Immediately north of Grande Terra, unenclosed, deeper waters predominate. The coral reefs around New Caledonia support an unusual diversity of species, including large numbers of predators and big fish, turtles, and the world’s third-largest dugong population. NASA image created by Jesse Allen, using Landsat data provided by the United States Geological Survey. Caption by Michon Scott. Instrument: Landsat 7 - ETM+ Credit: NASA/GSFC/Landsat NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook

  7. Clipperton, a possible future for atoll lagoons

    NASA Astrophysics Data System (ADS)

    Charpy, L.; Rodier, M.; Couté, A.; Perrette-Gallet, C.; Bley-Loëz, C.

    2010-09-01

    Closure of the Clipperton Island atoll (10°17' N 109°13' W), now a meromictic lake, is estimated to have occurred between 1839 and 1849. It was still closed in 2005. Brackish waters in the upper layer (0-10 m) were oxygenated, while saline waters in the deep layer (>20 m) were anoxic. Allowing for the methodological difficulties of earlier measurements, the physical characteristics of the lagoon did not seem to have changed significantly since the last expedition (1980). The intermediate layer between brackish and saline waters was characterized by a strong density gradient and a temperature inversion of up to 1.6°C. Microbial activity, water exchange between the deep layer and surrounding oceanic waters and the geothermal flux hypothesis are discussed. The low DIN and SRP concentrations observed in the upper layer, despite high nutrient input by seabird droppings, reflect the high nutrient uptake by primary producers as attested by the elevated overall gross primary production (6.6 g C m-2 day-1), and high suspended photosynthetic biomass (2.23 ± 0.23 μg Chl a l-1) and production (263 ± 27 μg C l-1 day-1). Phytoplankton composition changed in 67 years with the advent of new taxa and the disappearance of previously recorded species. The freshwater phytoplanktonic community comprised 43 taxa: 37 newly identified during the expedition and 6 previously noted; 16 species previously found were not seen in 2005. The closure of the lagoon, combined with the positive precipitation-evaporation budget characteristic of the region, has induced drastic changes in lagoon functioning compared with other closed atolls.

  8. Toward homogenization of Mediterranean lagoons and their loss of hydrodiversity

    NASA Astrophysics Data System (ADS)

    Ferrarin, Christian; Bajo, Marco; Bellafiore, Debora; Cucco, Andrea; De Pascalis, Francesca; Ghezzo, Michol; Umgiesser, Georg

    2014-08-01

    Lagoons are considered to be the most valuable systems of the Mediterranean coastal area, with crucial ecological, historical, economical, and social relevance. Climate change strongly affects coastal areas and can deeply change the status of transitional areas like lagoons. Herein we investigate the hydrological response of 10 Mediterranean lagoons to climate change by means of numerical models. Our results suggest that Mediterranean lagoons amplify the salinity and temperature changes expected for the open sea. Moreover, numerical simulations indicate that there will be a general loss of intralagoon and interlagoon variability of their physical properties. Therefore, as a result of climate change, we see on Mediterranean lagoons an example of a common process that in future may effect many coastal environments: that of homogenization of the physical characteristics with a tendency toward marinization.

  9. Macroalgae, nutrient cycles, and pollutants in the lagoon of Venice

    SciTech Connect

    Sfriso, A.; Pavoni, B.; Marcomini, A.; Orio, A.A. )

    1992-12-01

    The Lagoon of Venice is a wide, shallow coastal basin that extends for about 50 km along the northwest coast of the Adriatic Sea. The lagoon has been substantially modified through the actions of man over the last century through the artificial control of the hydraulic dynamics of the lagoon including the construction of channels to facilitate navigation. The lagoon is subjected to considerable pollutant loading through the drainage of land under cultivation, municipal sewage, and industrial effluents. In this paper are reported the results of observations designed to document recent changes in macroalgal species composition, seasonal cycles of primary producers and nutrient levels, and the effects of the macroalgal community on concentrations of organic and inorganic pollutants. The dominant macroalgae in the lagoon was Ulva rigida, and the levels of plant nutrients and pollutants were influenced by the seasonal cycles of the macroalgal community. 44 refs., 11 figs., 2 tabs.

  10. Kinetics of methane oxidation in selected mineral soils

    NASA Astrophysics Data System (ADS)

    Walkiewicz, A.; Bulak, P.; Brzeziñska, M.; Włodarczyk, T.; Polakowski, C.

    2012-10-01

    The kinetic parameters of methane oxidation in three mineral soils were measured under laboratory conditions. Incubationswere preceded by a 24-day preincubationwith 10%vol. of methane. All soils showed potential to the consumption of added methane. None of the soils, however, consumed atmospheric CH4. Methane oxidation followed the Michaelis-Menten kinetics, with relatively low values of parameters for Eutric Cambisol, while high values for Haplic Podzol, and especially for Mollic Gleysol which showed the highest methanotrophic activity and much lower affinity to methane. The high values of parameters for methane oxidation are typical for organic soils and mineral soils from landfill cover. The possibility of the involvement of nitrifying microorganisms, which inhabit the ammonia-fertilized agricultural soils should be verified.

  11. Denitrification in anaerobic lagoons used to treat swine wastewater.

    PubMed

    Hunt, P G; Matheny, T A; Ro, K S; Vanotti, M B; Ducey, T F

    2010-01-01

    Anaerobic lagoons are commonly used for the treatment of swine wastewater. Although these lagoons were once thought to be relatively simple, their physical, chemical, and biological processes are very complex. This study of anaerobic lagoons had two objectives: (i) to quantify denitrification enzyme activity (DEA) and (ii) to evaluate the influence of lagoon characteristics on the DEA. The DEA was measured by the acetylene inhibition method. Wastewater samples and physical and chemical measurements were taken from the wastewater column of nine anaerobic swine lagoons from May 2006 to May 2009. These lagoons were typical for anaerobic swine lagoons in the Carolinas relative to their size, operation, and chemical and physical characteristics. Their mean value for DEA was 87 mg N2O-N m(-3) d(-1). In a lagoon with 2-m depth, this rate of DEA would be compatible with 1.74 kg N ha(-1) d(-1) When nonlimiting nitrate was added, the highest DEA was compatible with 4.38 kg N ha(-1) d(-1) loss. Using stepwise regression for this treatment, the lagoon characteristics (i.e., soluble organic carbon, total nitrogen, temperature, and NO3-N) provided a final step model R2 of 0.69. Nitrous oxide from incomplete denitrification was not a significant part of the system nitrogen balance. Although alternate pathways of denitrification may exist within or beneath the wastewater column, this paper documents the lack of sufficient denitrification enzyme activity within the wastewater column of these anaerobic lagoons to support large N2 gas losses via classical nitrification and denitrification.

  12. Homicide by methane gas.

    PubMed

    De-Giorgio, Fabio; Grassi, Vincenzo M; Vetrugno, Giuseppe; Rossi, Riccardo; Fucci, Nadia; d'Aloja, Ernesto; Pascali, Vincenzo L

    2012-09-10

    Methane is a suffocating gas, and "methane deaths" are largely the result of suffocation by gas-air displacement after accidental or deliberate exposure. Neither methane gas nor other suffocating gases are a common means of homicide, with the potential exception of the use of gas in chemical weapons or gas chambers. Here, we report the case of a 53-year-old woman who was killed by her husband with methane gas. The man had given his wife a dose of Lorazepam before setting up a hose that conveyed methane from the kitchen into the apartment's bedroom. The man subsequently faked his own suicide, which was later discovered.

  13. Sky cover

    NASA Astrophysics Data System (ADS)

    Gerth, Jordan J.

    Of all of the standard meteorological parameters collected and observed daily, sky cover is not only one of the most complex, but the one that is fairly ambiguously defined and difficult to quantify. Despite that, the implications of how cloud fraction and sky cover are understood not only impact daily weather forecasts, but also present challenges to assessing the state of the earth's climate system. Part of the reason for this is the lack of observational methods for verifying the skill of clouds represented and parameterized in numerical models. While human observers record sky cover as part of routine duties, the spatial coverage of such observations in the United States is relatively sparse. There is greater spatial coverage of automated observations, and essentially complete coverage from geostationary weather satellites that observe the Americas. A good analysis of sky cover reconciles differences between manual observations, automated observations, and satellite observations, through an algorithm that accounts for the strengths and weaknesses of each dataset. This work describes the decision structure for trusting and weighting these similar observations. Some of the issues addressed include: human and instrument error resulting from approximations and estimations, a deficiency in high cloud detectability using surface-based ceilometers, poorly resolved low cloud using infrared channels on space-based radiometers during overnight hours, and decreased confidence in satellite-detected cloud during stray light periods. Using the blended sky cover analysis as the best representation of cloudiness, it is possible to compare the analysis to numerical model fields in order to assess the performance of the model and the parameterizations therein, as well as confirm or uncover additional relationships between sky cover and pertinent fields using an optimization methodology. The optimizer minimizes an affine expression of adjusted fields to the "truth" sky cover

  14. Sludge Lagoons. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

    ERIC Educational Resources Information Center

    Sharman, Ronald M.

    This lesson describes three different types of sludge lagoons: (1) drying lagoons; (2) facultative lagoons; and (3) anaerobic lagoons. Normal operating sequence and equipment are also described. The lesson is designed to be used in sequence with the complete Sludge Treatment and Disposal Course #166 or as an independent lesson. The instructor's…

  15. Impact of cross-reef water fluxes on lagoon dynamics: a simple parameterization for coral lagoon circulation model, with application to the Ouano Lagoon, New Caledonia

    NASA Astrophysics Data System (ADS)

    Chevalier, Cristele; Sous, Damien; Devenon, Jean-Luc; Pagano, Marc; Rougier, Gilles; Blanchot, Jean

    2015-11-01

    This manuscript presents a combined experimental and numerical study of the impact of cross-reef fluxes on coral reef lagoon dynamics. The selected field site is the Ouano Lagoon (New Caledonia Island, France) in the South Western Pacific Ocean. Measurements of wave transformation above the reef and current profiles through passages and reef openings have been carried out during a 3-month survey. Data analysis reveals the preponderant roles played by both tides and waves on the lagoon dynamics. Based on field data, a simple parameterization of cross-reef fluxes is implemented in a coastal lagoon circulation model and a satisfactory agreement is found between parameterized model and field results. The model is thus used as a numerical experimental tool in order to analyse the cross-reef flows' possible influence on a narrow lagoon dynamics. The results highlight the importance of cross-reef fluxes induced by wave breaking over the reef barrier on the whole lagoon circulation and water properties.

  16. Hypertrophic lagoon management by sediment disturbance.

    PubMed

    Lenzi, Mauro; Birardi, Francesca; Calzolai, Roberto; Finoia, Maria Grazia; Marcone, Francesco; Nocciolini, Stefano; Roffilli, Rugiada; Sgroi, Sergio; Solari, Duccio

    2010-01-01

    Experimental control of eutrophication in a small coastal lagoon was attempted by means of sediment disturbance. A specially designed boat was used to resuspend the top 3 cm of sediment by a jets of air-water directed towards the bottom. This disturbance was carried out for 3 months in each of two areas with a surface area of 24 and 20 hectares respectively. In a total of 80 stations in these two areas and in two undisturbed areas of 16 and 20 ha, organic matter, porosity, density and redox potential were monitored in sediment bimonthly and free sulphides were monitored in water close to the bottom. Before, during and after disturbance, the impact of daily sediment resuspension on the water column was monitored monthly, as ammonium nitrogen (N-NH4), soluble reactive phosphorus (SRP), dissolved oxygen (DO) and pH. In the whole lagoon, sediment texture was determined at the start and at the end of the experiment in 120 stations, and seaweed (mainly Chaetomorpha linum and Lophosiphonia subadunca) and seagrass (Ruppia cirrhosa) biomasses were estimated in 42 stations every month. The results showed a stable organic matter content in disturbed areas and an increase in undisturbed areas, as well as an increase in seaweed in areas distant from disturbed areas. No significant effect of sediment resuspension on water column N-NH4, SRP, DO or pH was found.

  17. Methane photochemistry and methane production on Neptune

    SciTech Connect

    Romani, P.N.; Atreya, S.K.

    1988-06-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus. 65 references.

  18. Methane photochemistry and methane production on Neptune

    NASA Astrophysics Data System (ADS)

    Romani, P. N.; Atreya, S. K.

    1988-06-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  19. Methane photochemistry and methane production on Neptune

    NASA Technical Reports Server (NTRS)

    Romani, P. N.; Atreya, S. K.

    1988-01-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  20. Methane photochemistry and methane production on Neptune

    NASA Technical Reports Server (NTRS)

    Romani, P. N.; Atreya, S. K.

    1988-01-01

    The Neptune stratosphere's methane photochemistry is presently studied by means of a numerical model in which the observed mixing ratio of methane prompts photolysis near the CH4 homopause. Haze generation by methane photochemistry has its basis in the formation of hydrocarbon ices and polyacetylenes; the hazes can furnish the requisite aerosol haze at the appropriate pressure levels required by observations of Neptune in the visible and near-IR. Comparisons of model predictions with Uranus data indicate a lower ratio of polyacetylene production to hydrocarbon ice, as well as a lower likelihood of UV postprocessing of the acetylene ice to polymers on Neptune, compared to Uranus.

  1. Clumped Methane Isotopologue Temperatures of Microbial Methane

    NASA Astrophysics Data System (ADS)

    Ono, S.; Wang, D. T.; Gruen, D.; Delwiche, K.; Hemond, H.; Pohlman, J.

    2014-12-01

    We will report the abundance of 13CH3D, a clumped isotopologue of methane, in microbial methane sampled from natural environments. They yield some expected and some unexpected results reflecting both equilibrium and kinetic isotope effects controlling the abundance of 13CH3D in low temperature environments. The four isotopologues of methane (12CH4, 13CH4, 12CH3D and 13CH3D) were measured by a tunable infrared spectroscopy method at a precision of 0.2‰ and accuracy of 0.5‰ (Ono et al., 2014). Similar to carbonate clumped isotope thermometry, clumped isotopologues of methane become more stable at lower temperatures. The equilibrium constant for the isotope exchange reaction 13CH4 + 12CH3D ⇌ 13CH3D + 12CH4 deviates from unity by +6.3 to +3.5 ‰ for methane equilibrated between 4 and 121 °C, a range expected for microbial methanogenesis. This would be measurably-distinct from a thermogenic methane signal, which typically have apparent 13CH3D-based temperatures ranging from 150 to 220 °C (+3.0 to +2.2 ‰ clumped isotope effect; Ono et al., 2014; Stolper et al. 2014). Marine samples, such as methane clathrates and porewater methane from the Cascadia margin, have 13CH3D-based temperatures that appear to be consistent with isotopic equilibration at in situ temperatures that are reasonable for deep sedimentary environments. In contrast, methane from freshwater environments, such as a lake and a swamp, yield apparent temperatures that are much higher than the known or inferred environmental temperature. Mixing of two or more distinct sources of methane could potentially generate this high temperature bias. We suggest, however, that this high-temperature bias likely reflects a kinetic isotope fractionation intrinsic to methanogenesis in fresh water environments. In contrast, the low-temperature signals from marine methane could be related to the slow metabolic rates and reversibility of microbial methanogenesis and methanotrophy in marine sedimentary environments

  2. Acid Tar Lagoons: Management and Recovery

    NASA Astrophysics Data System (ADS)

    Bohers, Anna; Hroncová, Emília; Ladomerský, Juraj

    2017-04-01

    This contribution presents the issue with possibility of definitive removal of dangerous environmental burden in Slovakia - serious historical problem of two acid tar lagoons. In relation to their removal, no technology has been found so far - technologically and economically suitable, what caused problems with its management. Locality Predajná is well known in Slovakia by its character of contrasts: it is situated in the picturesque landscape of National Park buffer zone of Nízke Tatry, on the other site it is contaminated by 229 211m3 of acid tar with its characteristics of toxicity, carcinogenicity, teratogenicity, mutagenicity and toxicity especially for animals and plants. Acid tar in two landfills with depth of 1m in case of the first lagoon and 9,5m in case of the second lagoon is a waste product derived from operation of Petrochema Dubová - refinery and petrochemical plant whose activity was to process the crude oil through processes of sulfonation and adsorption technology for producing lubricating and special oils, synthetic detergents and special white oils for cosmetic and medical purposes. A part of acid tar was incinerated in two incineration plats. Concentration of SO2 in combustion gases was too high and it was not possible to decrease it under the value of 2000 mg.mn-3 [LADOMERSKÝ, J. - SAMEŠOVÁ, D.: Reduction in sulfur dioxide emissions waste gases of incineration plant. Acta facultatis ecologiae. 1999, p. 217-223]. That is why it was necessary to put them out of operation. Later, because of public opposition it was not possible to build a new incineration plat corresponding to the state of the art. Even though actual Slovak and European legislative for protection of environment against such impacts, neither of tried methods - bio or non-biologic treatment methods - was proved as suitable for processing or for recovery in the reason of different factors admission: i.e. strong aggressivity, difficulty with handling because of its sludgy and

  3. Metals in sediments of San Andres lagoon, Tamaulipas, Mexico

    SciTech Connect

    Vazquez, F.G.; Aguilera, L.G. ); Sharma, V.K. )

    1994-03-01

    Heavy metal pollution in water is generally associated with industrial and municipal discharges into rivers, estuaries and lagoons. Once metals are in the water column, they may be taken up by organisms, deposited in the sediments or remain for some period in the water itself. The deposition rate in sediments depends on, among other factors, metal concentration in surface sediments. The concentrations of heavy metals in sediments of coastal, estuarine and lagoon environments have been determined by many workers. For the past several years, we have been interested in determining trace and heavy metal concentrations in the lagoons in Mexico to establish the levels of metal pollution. The work reported here is the completion of our ongoing study in San Andres lagoon. San Andres lagoon is located north of two industrial ports, Tampico and Altamira. In this industrial zone, the basins of the Panuco and Tamesi Rivers are localized and have industrial effluent throughout the year. All these activities and the input of the Tigre River, which runs through an agricultural and cattle-raising region, may affect the biogeochemistry of the San Andres lagoon. In the present work, we report concentrations of Cd, Co, Cu, Fe, Mn, Ni, Zn and Pb in sediments of San Andres lagoon. The measurements were made in different seasons; Rain-84 (August-September 1984); North (October-December 1984); Dry (April 1985); and Rain-85 (April-June 1985). 13 refs., 1 fig., 2 tabs.

  4. Both riverine detritus and dissolved nutrients drive lagoon fisheries

    NASA Astrophysics Data System (ADS)

    Bonthu, Subbareddy; Ganguly, Dipnarayan; Ramachandran, Purvaja; Ramachandran, Ramesh; Pattnaik, Ajit K.; Wolanski, Eric

    2016-12-01

    The net ecosystem metabolism in lagoons has often been estimated from the net budget of dissolved nutrients. Such is the case of the LOICZ estuarine biogeochemistry nutrient budget model that considers riverine dissolved nutrients, but not riverine detritus. However the neglect of detritus can lead to inconsistencies; for instance, it results in an estimate of 5-10 times more seaward export of nutrients than there is import from rivers in Chilika Lagoon, India. To resolve that discrepancy the UNESCO estuarine ecohydrology model, that considers both dissolved nutrients and detritus, was used and, for Chilika Lagoon, it reproduced successfully the spatial distribution of salinity, dissolved nutrients, phytoplankton and zooplankton as well as the fish yield data. Thus the model suggests that the riverine input of both detritus and dissolved nutrients supports the pelagic food web. The model also reproduces well the observation of decreased fish yield when the mouth of the lagoon was choked in the 1990s, demonstrating the importance of the physics that determine the flushing rate of waterborne matter. Thus, both farming in the watershed by driving the nutrient and detritus inputs to the lagoon, and dredging and engineering management of the mouth by controlling the flushing rate of the lagoon, have a major influence on fish stocks in the lagoon.

  5. Multi-centennial scale precipitation and following lagoon ecosystem fluctuation in the Holocene reconstructed by East Korean Lagoon sediment analysis

    NASA Astrophysics Data System (ADS)

    Katsuki, K.; Yang, D. Y.; Lim, J.; Nahm, W. H.; Nakanishi, T.; Seto, K.; Otsuka, M.; Kashima, K.

    2014-12-01

    There are lagoons in the northern east coast of the South Korea, which were formed during the transgression period in the early Holocene. These lagoons shrank about 5-30 % during the first half of 20 century due to terrestrial sediment input from soil erosion in reclamation lands. However, buried lagoonal sediments record Holocene climate change. In this study, multi-centennial scale paleo-climate and paleo-ecosystem change were investigated by analysis of this buried and present lagoon deposits. Based on the diatom assemblage analysis of the sediment in the lagoon Maeho where it is the east coast lagoons in Korea, this lagoon was formed about 8,400 years ago, and halophilic diatoms showed high peaks at three times within the last 8,400 years. Timings of these peaks were well coincident with the high-sea level periods reported in the western Japan. It is considered that sea-level of the east coast in Korea also showed high at three times during the mid-late Holocene, and then, salinity of the lagoon increased in these periods. Except for such sea-level dependent change, salinity of the lagoon Maeho showed the multi-centennial (200 or 400 years) scale periodic variation. Magnetic susceptibility (MS) also showed the clear 400 years periodicity in the mid-late Holocene. When the MS showed high value, oligohalobous diatoms showed high value. However, halophilic diatoms and number of total diatom valves increased when the MS showed low value. This correspondence probably indicates that magnetic minerals flew into the lagoon with river fresh water, and then volume of fresh water inflow has changed with 400 years cycles. Such MS cycle was also confirmed in the sediments of other lagoons. Change of fresh water inflow should be not local event, was a part of regional environmental change. These results probably indicate that the precipitation on the northeastern South Korea has changed by the 400 years cycle. On the basis of lagoon bottom sediment, it made clear that the

  6. Global Methane Biogeochemistry

    NASA Astrophysics Data System (ADS)

    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

  7. Methane emission from sewers.

    PubMed

    Liu, Yiwen; Ni, Bing-Jie; Sharma, Keshab R; Yuan, Zhiguo

    2015-08-15

    Recent studies have shown that sewer systems produce and emit a significant amount of methane. Methanogens produce methane under anaerobic conditions in sewer biofilms and sediments, and the stratification of methanogens and sulfate-reducing bacteria may explain the simultaneous production of methane and sulfide in sewers. No significant methane sinks or methanotrophic activities have been identified in sewers to date. Therefore, most of the methane would be emitted at the interface between sewage and atmosphere in gravity sewers, pumping stations, and inlets of wastewater treatment plants, although oxidation of methane in the aeration basin of a wastewater treatment plant has been reported recently. Online measurements have also revealed highly dynamic temporal and spatial variations in methane production caused by factors such as hydraulic retention time, area-to-volume ratio, temperature, and concentration of organic matter in sewage. Both mechanistic and empirical models have been proposed to predict methane production in sewers. Due to the sensitivity of methanogens to environmental conditions, most of the chemicals effective in controlling sulfide in sewers also suppress or diminish methane production. In this paper, we review the recent studies on methane emission from sewers, including the production mechanisms, quantification, modeling, and mitigation.

  8. Climate Impacts of Cover Crops

    NASA Astrophysics Data System (ADS)

    Lombardozzi, D.; Wieder, W. R.; Bonan, G. B.; Morris, C. K.; Grandy, S.

    2016-12-01

    Cover crops are planted in agricultural rotation with the intention of protecting soil rather than harvest. Cover crops have numerous environmental benefits that include preventing soil erosion, increasing soil fertility, and providing weed and pest control- among others. In addition to localized environmental benefits, cover crops can have important regional or global biogeochemical impacts by increasing soil organic carbon, changing emissions of greenhouse trace gases like nitrous oxide and methane, and reducing hydrologic nitrogen losses. Cover crops may additionally affect climate by changing biogeophysical processes, like albedo and latent heat flux, though these potential changes have not yet been evaluated. Here we use the coupled Community Atmosphere Model (CAM5) - Community Land Model (CLM4.5) to test how planting cover crops in the United States may change biogeophysical fluxes and climate. We present seasonal changes in albedo, heat fluxes, evaporative partitioning, radiation, and the resulting changes in temperature. Preliminary analyses show that during seasons when cover crops are planted, latent heat flux increases and albedo decreases, changing the evaporative fraction and surface temperatures. Understanding both the biogeophysical changes caused by planting cover crops in this study and the biogeochemical changes found in other studies will give a clearer picture of the overall impacts of cover crops on climate and atmospheric chemistry, informing how this land use strategy will impact climate in the future.

  9. Hydrogen Sulfide Emissions from Sow Farm Lagoons across Climates Zones.

    PubMed

    Grant, Richard H; Boehm, Matthew T; Lawrence, Alfred J; Heber, Albert J

    2013-11-01

    Hydrogen sulfide (HS) emissions were measured periodically over the course of 2 yr at three sow waste lagoons representing humid mesothermal (North Carolina, NC), humid microthermal (Indiana, IN), and semiarid (Oklahoma, OK) climates. Emissions were determined using a backward Lagrangian stochastic model in conjunction with line-sampled HS concentrations and measured turbulence. The median annual sow-specific (area-specific) lagoon emissions at the OK farm were approximately 1.6 g head [hd] d (5880 µg m s), whereas those at the IN and NC sow farms were 0.035 g hd d (130 µg m s), and 0.041 g hd d (260 µg m s), respectively. Hydrogen sulfide emissions generally increased with wind speed. The daily HS emissions from the OK lagoon were greatest during the first half of the year and decreased as the year progressed. Emissions were episodic at the NC and IN lagoons. The generally low emissions at the NC and IN lagoons were probably a result of significant populations of purple sulfur bacteria maintained in the humid mesothermal and humid microthermal climates. Most of the large HS emission events at the NC and IN lagoons appeared to be a result of either precipitation events or liquid pump-out events. The high emissions at the OK lagoon in a semiarid climate were largely a result of high wind speeds enhancing both lagoon and air boundary layer mixing. The climate (air temperature, winds, and precipitation) appeared to influence the HS emissions from lagoons. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  10. Wall Covering

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The attractive wall covering shown below is one of 132 styles in the Mirror Magic II line offered by The General Tire & Rubber Company, Akron, Ohio. The material is metallized plastic fabric, a spinoff from space programs. Wall coverings are one of many consumer applications of aluminized plastic film technology developed for NASA by a firm later bought by King-Seeley Thermos Company, Winchester, Massachusetts, which now produces the material. The original NASA use was in the Echo 1 passive communications satellite, a "space baloon" made of aluminized mylar; the high reflectivity of the metallized coating enabled relay of communications signals from one Earth station to another by "bouncing" them off the satellite. The reflectivity feature also made the material an extremely efficient insulator and it was subsequently widely used in the Apollo program for such purposes as temperature control of spacecraft components and insulation of tanks for fuels that must be maintained at very low temperatures. I Used as a wall covering, the aluminized material offers extra insulation, reflects light and I resists cracking. In addition to General Tire, King-Seeley also supplies wall covering material to Columbus Coated Fabrics Division of Borden, Incorporated, Columbus, Ohio, among others.

  11. Cover Crops

    USDA-ARS?s Scientific Manuscript database

    Cover crops are great tools to improve soil quality and health, and great tools to increase carbon sequestration. They are nutrient management tools that can help scavenge nitrate, cycle nitrogen to the following crop, mine NO3 from groundwater, and increase nitrogen use efficiency of cropping syste...

  12. A Century of changes for Razelm-Sinoe Lagoon System

    NASA Astrophysics Data System (ADS)

    Scrieciu, Marian-Albert; Stanica, Adrian

    2014-05-01

    A Century of changes for Razelm-Sinoe Lagoon System Marian-Albert Scrieciu (a), Adrian Stanica (a) (a) National Institute of Marine Geology and Geoecology e GeoEcoMar, Str. Dimitrie Onciul 23e25, Sector 2, 024053 Bucharest, Romania Razelm-Sinoe Lagoon System, situated in the NW part of the Black Sea, in tight connection with the Danube Delta, has been subject to major changes due to human interventions in the past century. These changes have resulted into a complete change of the Lagoon specific ecosystems compared to its pristine state. In its natural state, as brackish - transitional environment, Antipa (1894) mentions Razelm Lagoon as one of the places with the greatest fisheries around the Black Sea coast (about 1879 - 1884, there were approximately 10,000 fishermen, all working on the Razelm Sinoe Lagoon System). Starting with the end of the XIXth Century, new canals were dug and existing channels were dredged in order to develop tighter connections with the Danube River. The natural inlet of Portita was blocked four decades ago and connections between the various parts of the lagoon system were controlled by the building of locks and sluices. The 2 inlets of Sinoe Lagoon were also controlled during early 1980s. Under these conditions, the lagoon ecosystem changed from brackish towards freshwater, with major effects on the existing flora and fauna. The period of brutal interventions ended in 1989 and the Razelm-Sinoe Lagoon System became part of the Danube Delta Biosphere Reserve in 1991, with a strict policy of nature protection and restoration. Spatial planning has been the major management option for the entire reserve, lagoon system included. Plans for sustainable development of the Razelm-Sinoe Lagoon System have been built in a participative manner, involving the local stakeholders, as part of FP7 ARCH project. Special attention has been given to impacts of climate change. The study presents the vision for the development Razelm-Sinoe Lagoon System over

  13. Sources of atmospheric methane from wetlands

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Through the use of a computerized Geographic Information Service (GIS), field data on methane emissions and water inundation levels have been combined with remotely sensed vegetation cover data. This permits a more precise extrapolation of point flux measurements to regional scale flux estimates. Since the GIS allows changes in environmental variables to be included in the model, the sensitivity of emissions on large scales to changes in these parameters may be studied. Here, methane flux measurements from the Everglades marsh complex are reported, giving the flux by vegetation class.

  14. Sources of atmospheric methane from wetlands

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Through the use of a computerized Geographic Information Service (GIS), field data on methane emissions and water inundation levels have been combined with remotely sensed vegetation cover data. This permits a more precise extrapolation of point flux measurements to regional scale flux estimates. Since the GIS allows changes in environmental variables to be included in the model, the sensitivity of emissions on large scales to changes in these parameters may be studied. Here, methane flux measurements from the Everglades marsh complex are reported, giving the flux by vegetation class.

  15. Impact of different plants on the gas profile of a landfill cover

    SciTech Connect

    Reichenauer, Thomas G.; Watzinger, Andrea; Riesing, Johann; Gerzabek, Martin H.

    2011-05-15

    Research highlights: > Plants influence gas profile and methane oxidation in landfill covers. > Plants regulate water content and increase the availability of oxygen for methane oxidation. > Plant species with deep roots like alfalfa showed more stimulation of methane oxidation than plants with shallow root systems like grasses. - Abstract: Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa + grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa + grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content.

  16. Phosphorus metabolism in anthropogenically transformed lagoon ecosystems: The Comacchio lagoons (Ferrara, Italy)

    NASA Astrophysics Data System (ADS)

    Sorokin, Yuri I.; Dallocchio, Franco; Gelli, Fernando; Pregnolato, Luciano

    1996-06-01

    Inorganic phosphorus dynamics were investigated with the use of 32P in the hypertrophic Comacchio lagoons (NE Adriatic) during an extremely dense, quasi-permanent bloom of picocyanobacteria. Concentrations of dissolved inorganic phosphate (DIP) in waters of the blooming lagoons were usually near the detection limit (0.01 μmoles·dm -3). DIP uptake rates by microplankton at near-ambient concentrations (0.01 to 0.1 μmoles·dm -3) were in the range of 9.6 to 16.1 nmoles P·dm -3·min -1, and turnover times were 1.5 to 3 min. The turnover time was >40 h in the eutrophic coastal waters of the adjacent Adriatic Sea. The uptake rate of DIP depended on its initial concentration. In water samples artificially enriched with DIP, the uptake rate rose to its maximum of 0.10 to 0.13 μmoles P·dm -3·min -1 (or ˜6 to 7 μmoles·dm -3·h -1) when the initial concentration of DIP was elevated to 10 to 20 μmoles·dm -3. The potential capacity of microplankton in the water samples to consume and retain DIP was estimated at ˜25 μmoles·dm -3. Specific features are discussed of phosphorus metabolism in the anthropogenically transformed lagoon ecosystem with an anomalous food web with few animals.

  17. Methane-Powered Vehicles

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid methane is beginning to become an energy alternative to expensive oil as a power source for automotive vehicles. Methane is the principal component of natural gas, costs less than half as much as gasoline, and its emissions are a lot cleaner than from gasoline or diesel engines. Beech Aircraft Corporation's Boulder Division has designed and is producing a system for converting cars and trucks to liquid methane operation. Liquid methane (LM) is a cryogenic fuel which must be stored at a temperature of 260 degrees below zero Fahrenheit. The LM system includes an 18 gallon fuel tank in the trunk and simple "under the hood" carburetor conversion equipment. Optional twin-fuel system allows operator to use either LM or gasoline fuel. Boulder Division has started deliveries for 25 vehicle conversions and is furnishing a liquid methane refueling station. Beech is providing instruction for Northwest Natural Gas, for conversion of methane to liquid state.

  18. Mars methane engine

    NASA Technical Reports Server (NTRS)

    Bui, Hung; Coletta, Chris; Debois, Alain

    1994-01-01

    The feasibility of an internal combustion engine operating on a mixture of methane, carbon dioxide, and oxygen has been verified by previous design groups for the Mars Methane Engine Project. Preliminary stoichiometric calculations examined the theoretical fuel-air ratios needed for the combustion of methane. Installation of a computer data acquisition system along with various ancillary components will enable the performance of the engine, running on the described methane mixture, to be optimized with respect to minimizing excess fuel. Theoretical calculations for stoichiometric combustion of methane-oxygen-carbon dioxide mixtures yielded a ratio of 1:2:4.79 for a methane-oxygen-carbon dioxide mixture. Empirical data shows the values to be closer to 1:2.33:3.69 for optimum operation.

  19. Effects of land use changes on eutrophication indicators in five coastal lagoons of the Southwestern Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Rodríguez-Gallego, Lorena; Achkar, Marcel; Defeo, Omar; Vidal, Leticia; Meerhoff, Erika; Conde, Daniel

    2017-03-01

    Five catchment areas in Uruguay were selected to conduct a nutrient exportation analysis and to evaluate the effects of current land use on the eutrophication of coastal lagoons. Satellite images and national agriculture censuses were used for a quantitative analysis of land use changes from 1974 to 2005, and a nutrient export coefficient approximation was used to determine long-term changes in annual loads. Several eutrophication indicators (water, sediment and autotrophic communities) were assessed seasonally in the lagoon basins during 2005 and 2006. The areal annual load of nutrients exported to the lagoons increased over time. Population and extensive livestock ranching were the most important nutrient sources, while agriculture is increasing in importance. Buffer effects of riparian forests on eutrophication indicators were observed in contrast to the wetlands surrounding the lagoons, which seem to be acting as a source of nutrients. Catchment size was inversely related to most eutrophication indicators. Afforestation and agriculture were found not to directly impact eutrophication indicators, however, catchments with larger agricultural areas showed higher concentrations of suspended solids, which may indicate the export of particulate nutrients. Salinity was inversely related to most eutrophication indicators, suggesting that the manipulation of the sand bar of the lagoons is a critical management issue. Sediment-related eutrophication indicators were more sensitive to changes in land uses and covers, in contrast with the more variable water column indicators, suggesting their potential use as enduring indicators. This research provides a rapid and integral assessment for qualitatively linking catchment changes with eutrophication indicators in coastal environments, which can easily be replicated to track pollutants in locations that lack standardized monitoring programs needed for more complex catchment modeling approaches.

  20. Extreme flood event reconstruction spanning the last century in the El Bibane Lagoon (southeastern Tunisia): a multi-proxy approach

    NASA Astrophysics Data System (ADS)

    Affouri, Aida; Dezileau, Laurent; Kallel, Nejib

    2017-06-01

    Climate models project that rising atmospheric carbon dioxide concentrations will increase the frequency and the severity of some extreme weather events. The flood events represent a major risk for populations and infrastructures settled on coastal lowlands. Recent studies of lagoon sediments have enhanced our knowledge on extreme hydrological events such as palaeo-storms and on their relation with climate change over the last millennium. However, few studies have been undertaken to reconstruct past flood events from lagoon sediments. Here, the past flood activity was investigated using a multi-proxy approach combining sedimentological and geochemical analysis of surfaces sediments from a southeastern Tunisian catchment in order to trace the origin of sediment deposits in the El Bibane Lagoon. Three sediment sources were identified: marine, fluvial and aeolian. When applying this multi-proxy approach on core BL12-10, recovered from the El Bibane Lagoon, we can see that finer material, a high content of the clay and silt, and a high content of the elemental ratios (Fe / Ca and Ti / Ca) characterise the sedimentological signature of the palaeo-flood levels identified in the lagoonal sequence. For the last century, which is the period covered by the BL12-10 short core, three palaeo-flood events were identified. The age of these flood events have been determined by 210Pb and 137Cs chronology and give ages of AD 1995 ± 6, 1970 ± 9 and 1945 ± 9. These results show a good temporal correlation with historical flood events recorded in southern Tunisia in the last century (AD 1932, 1969, 1979 and 1995). Our finding suggests that reconstruction of the history of the hydrological extreme events during the upper Holocene is possible in this location through the use of the sedimentary archives.

  1. Methane emissions from cattle.

    PubMed

    Johnson, K A; Johnson, D E

    1995-08-01

    Increasing atmospheric concentrations of methane have led scientists to examine its sources of origin. Ruminant livestock can produce 250 to 500 L of methane per day. This level of production results in estimates of the contribution by cattle to global warming that may occur in the next 50 to 100 yr to be a little less than 2%. Many factors influence methane emissions from cattle and include the following: level of feed intake, type of carbohydrate in the diet, feed processing, addition of lipids or ionophores to the diet, and alterations in the ruminal microflora. Manipulation of these factors can reduce methane emissions from cattle. Many techniques exist to quantify methane emissions from individual or groups of animals. Enclosure techniques are precise but require trained animals and may limit animal movement. Isotopic and nonisotopic tracer techniques may also be used effectively. Prediction equations based on fermentation balance or feed characteristics have been used to estimate methane production. These equations are useful, but the assumptions and conditions that must be met for each equation limit their ability to accurately predict methane production. Methane production from groups of animals can be measured by mass balance, micrometeorological, or tracer methods. These techniques can measure methane emissions from animals in either indoor or outdoor enclosures. Use of these techniques and knowledge of the factors that impact methane production can result in the development of mitigation strategies to reduce methane losses by cattle. Implementation of these strategies should result in enhanced animal productivity and decreased contributions by cattle to the atmospheric methane budget.

  2. Detecting Methane Leaks

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Hinkley, E. D.

    1984-01-01

    Remote sensor uses laser radiation backscattered from natural targets. He/Ne Laser System for remote scanning of Methane leaks employs topographic target to scatter light to receiver near laser transmitter. Apparatus powered by 1.5kW generator transported to field sites and pointed at suspected methane leaks. Used for remote detection of natural-gas leaks and locating methane emissions in landfill sites.

  3. White pelicans swim in the lagoon

    NASA Technical Reports Server (NTRS)

    1999-01-01

    White pelicans search for a meal in the waters of the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The habitat of white pelicans are marshy lakes along the Pacific and Texas coasts, wintering chiefly in coastal lagoons such as this one. They often capture fish cooperatively, forming a long line, beating their wings and driving the prey into shallow water. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  4. White pelicans swim in the lagoon

    NASA Technical Reports Server (NTRS)

    1999-01-01

    White pelicans search for a meal in the waters of the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The habitat of white pelicans are marshy lakes along the Pacific and Texas coasts, wintering chiefly in coastal lagoons such as this one. They often capture fish cooperatively, forming a long line, beating their wings and driving the prey into shallow water. The 92,000-acre refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles. The marshes and open water of the refuge also provide wintering areas for 23 species of migratory waterfowl, as well as a year-round home for great blue herons, great egrets, wood storks, cormorants, brown pelicans and other species of marsh and shore birds.

  5. Foraminiferal Evidence of Sediment Deformation Caused by Late Holocene Faulting in a Backbarrier Lagoon, Matagorda, Texas, USA

    NASA Astrophysics Data System (ADS)

    Brunner, C. A.; Yeager, K. M.; Feagin, R. A.

    2014-12-01

    The onset of a normal faulting event was observed in the late Holocene lagoon of the Matagorda Island, Texas. The faulting caused differential elevation changes across a transect perpendicular to the fault―much as it is doing in a present-day faulting event initiated after the 1940's. The interpretation comes from assemblages of benthic foraminifera and supports other sedimentary evidence. A 115-m-long transect of seven vibracores was sampled across the active fault that cuts the Matagorda Island east of the Colorado River. Three cores lie on the upthrown block north of the fault, and four cores lie to the south on the downthrown block. The 1- to 4-m-long cores were split, described, and sampled at 20-cm intervals for foraminifera. Sediment subsamples of 0.25 cm3were washed on a sieve with 63-µm openings, split, and whole splits were picked until 100-300 specimens were recovered. Specimens were identified to species and tabulated. Samples were also taken at irregular intervals for radiocarbon dating. The sediment section consists of lagoonal olive-brown (2. 5Y) mud and muddy sand intercalated by cleaner sand units (potentially overwash deposits) and oyster shell hash, all overlain by the brownish (10YR) subaerial sand of the barrier island. The mud and muddy sand contain high densities of foraminifera consisting of two assemblages: a diverse assemblage containing near equal numbers of miliolids and rotalids typical of a deep lagoon, and a low diversity assemblage dominated by Elphidiidae and Ammonia, a rotalid assemblage typical of lagoonal shoals. The latter is also associated with oyster shell hash and blades of the sea grass Halodule wrightii. The diverse assemblage is found throughout the muddy lagoonal sediment south of the fault up to the subaerial sands of Matagorda Island. In contrast, the foraminiferal assemblage grades upsection from the high- to the low-diversity assemblage after ~2500 yBP north of the fault, and is subsequently covered by the barrier

  6. Self-generated morphology in lagoon reefs.

    PubMed

    Blakeway, David; Hamblin, Michael G

    2015-01-01

    The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia's Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves-specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef.

  7. Self-generated morphology in lagoon reefs

    PubMed Central

    Hamblin, Michael G.

    2015-01-01

    The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia’s Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves—specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef. PMID:26175962

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

    SciTech Connect

    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.

  9. Mercury methylation and demethylation in Hg-contaminated lagoon sediments (Marano and Grado Lagoon, Italy)

    NASA Astrophysics Data System (ADS)

    Hines, Mark E.; Poitras, Erin N.; Covelli, Stefano; Faganeli, Jadran; Emili, Andrea; Žižek, Suzana; Horvat, Milena

    2012-11-01

    Mercury (Hg) transformation activities and sulfate (SO42-) reduction were studied in sediments of the Marano and Grado Lagoons in the Northern Adriatic Sea region as part of the "MIRACLE" project. The lagoons, which are sites of clam (Tapes philippinarum) farming, have been receiving excess Hg from the Isonzo River for centuries. Marano Lagoon is also contaminated from a chlor-alkali plant. Radiotracer methods were used to measure mercury methylation (230Hg, 197Hg), methylmercury (MeHg) demethylation (14C-MeHg) and SO42- reduction (35S) in sediment cores collected in autumn, winter and summer. Mercury methylation rate constants ranged from near zero to 0.054 day-1, generally decreased with depth, and were highest in summer. Demethylation rate constants were much higher than methylation reaching values of ˜0.6 day-1 in summer. Demethylation occurred via the oxidative pathway, except in winter when the reductive pathway increased in importance in surficial sediments. Sulfate reduction was also most active in summer (up to 1600 nmol mL-1 day-1) and depth profiles reflected seasonally changing redox conditions near the surface. Methylation and demethylation rate constants correlated positively with SO42- reduction and pore-water Hg concentrations, and inversely with Hg sediment-water partition coefficients indicating the importance of SO42- reduction and Hg dissolution on Hg cycling. Hg transformation rates were calculated using rate constants and concentrations of Hg species. In laboratory experiments, methylation was inhibited by amendments of the SO42--reduction inhibitor molybdate and by nitrate. Lagoon sediments displayed a dynamic seasonal cycle in which Hg dissolution in spring/summer stimulated Hg methylation, which was followed by a net loss of MeHg in autumn from demethylation. Sulfate-reducing bacteria (SRB) tended to be responsible for methylation of Hg and the oxidative demethylation of MeHg. However, during winter in surficial sediments, iron

  10. VISTA Stares Deeply into the Blue Lagoon

    NASA Astrophysics Data System (ADS)

    2011-01-01

    This new infrared image of the Lagoon Nebula was captured as part of a five-year study of the Milky Way using ESO's VISTA telescope at the Paranal Observatory in Chile. This is a small piece of a much larger image of the region surrounding the nebula, which is, in turn, only one part of a huge survey. Astronomers are currently using ESO's Visible and Infrared Survey Telescope for Astronomy (VISTA) to scour the Milky Way's central regions for variable objects and map its structure in greater detail than ever before. This huge survey is called VISTA Variables in the Via Lactea (VVV) [1]. The new infrared image presented here was taken as part of this survey. It shows the stellar nursery called the Lagoon Nebula (also known as Messier 8, see eso0936), which lies about 4000-5000 light-years away in the constellation of Sagittarius (the Archer). Infrared observations allow astronomers to peer behind the veil of dust that prevents them from seeing celestial objects in visible light. This is because visible light, which has a wavelength that is about the same size as the dust particles, is strongly scattered, but the longer wavelength infrared light can pass through the dust largely unscathed. VISTA, with its 4.1-metre diameter mirror - the largest survey telescope in the world - is dedicated to surveying large areas of the sky at near-infrared wavelengths deeply and quickly. It is therefore ideally suited to studying star birth. Stars typically form in large molecular clouds of gas and dust, which collapse under their own weight. The Lagoon Nebula, however, is also home to a number of much more compact regions of collapsing gas and dust, called Bok globules [2]. These dark clouds are so dense that, even in the infrared, they can block the starlight from background stars. But the most famous dark feature in the nebula, for which it is named, is the lagoon-shaped dust lane that winds its way through the glowing cloud of gas. Hot, young stars, which give off intense

  11. Seasonal variation in a tropical lagoon with submarine groundwater discharges

    NASA Astrophysics Data System (ADS)

    Tenorio, L.; Gómez-Valdés, J.; Enriquez, C.; Treviño, C.; Marino-Tapia, I.; López-Aguiar, K.

    2013-05-01

    The Chelem-Chuburna-Yucalpeten lagoon system is located at 21°17'N and 89°40'W in the Yucatan peninsula, Mexico. Temperature, conductivity, sea level, atmospheric pressure, solar radiation, and wind speed measurements were recorded in this lagoon, during various oceanographic surveys within 2010-2012. During the experiments, which included diurnal variations during spring and neap tidal cycles, CTD profiles were collected in 35 oceanographic stations and moored instruments were deployed at strategic locations. The aim of this work is to investigate transitions of thermohaline properties in a tropical lagoon with submarine groundwater discharges (SGDs) to increase the knowledge of the principal processes that control circulation and mixing in this kind of bodies of water. Results show that the lagoon is saltier than the ocean in the dry season and the opposite pattern is observed in the rain season. During the rain season could be more freshwater supplied from SGDs.

  12. ANALYSIS OF SWINE LAGOONS AND GROUND WATER FOR ENVIRONMENTAL ESTROGENS

    EPA Science Inventory

    A method was developed for analysis of low levels of natural (estradiol, estrone, estriol) and synthetic (ethynylestradiol) estrogens in ground water and swine waste lagoon effluent. The method includes solid phase extraction of the estrogens, preparation of pentafluorobenzyl der...

  13. Region 8 NPDES Lagoon General Permit Notice of Intent Form

    EPA Pesticide Factsheets

    Adobe Acrobat fillable form of the Notice of Intent for Coverage under the EPA Region 8 Lagoon General Permit for Wastewater Systems located in Indian Country in Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming.

  14. Nutrient removal from swine lagoon effluent by duckweed

    SciTech Connect

    Bergmann, B.A.; Cheng, J.; Classen, J.; Stomp, A.M.

    2000-04-01

    Three duckweed geographic isolates were grown on varying concentrations of swine lagoon effluent in a greenhouse to determine their ability to remove nutrients from the effluent. Duckweed biomass was harvested every other day over a 12-day period. Duckweed biomass production, nutrient loss from the swine lagoon effluent, and nutrient content of duckweed biomass were used to identify effluent concentrations/geographic isolate combinations that are effective in terms of nutrient utilization from swine lagoon effluent and production of healthy duckweed biomass. When Lemna minor geographic isolate 8627 was grown on 50% swine lagoon effluent, respective losses of TKN, NH{sub 3}-N, TP, OPO{sub 4}-P, TOC, K, Cu, and Zn were 83, 100, 49, 31, 68, 21, 28 and 67%.

  15. ANALYSIS OF SWINE LAGOONS AND GROUND WATER FOR ENVIRONMENTAL ESTROGENS

    EPA Science Inventory

    A method was developed for analysis of low levels of natural (estradiol, estrone, estriol) and synthetic (ethynylestradiol) estrogens in ground water and swine waste lagoon effluent. The method includes solid phase extraction of the estrogens, preparation of pentafluorobenzyl der...

  16. ANALYSIS OF SWINE LAGOONS AND GROUND WATER FOR ENVIRONMENTAL ESTROGENS

    EPA Science Inventory

    A method was developed for analysis of low levels of natural (estradiol, estrone, estriol) and synthetic (ethinyl estradiol) estrogens in ground water and swine waste lagoon effluent. The method includes solid phase extraction of the estrogens, preparation of pentafluorobenzyl de...

  17. 13. Sewage treatment lagoon, drainage control at center left, looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Sewage treatment lagoon, drainage control at center left, looking south - Ellsworth Air Force Base, Delta Flight, Launch Control Facility, County Road CS23A, North of Exit 127, Interior, Jackson County, SD

  18. 1. Oblique view: east side, from Condado Lagoon Beach on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Oblique view: east side, from Condado Lagoon Beach on southeast (context) - Puente Guillermo Esteves, Spanning San Antonio Channel at PR-25 (Juan Ponce de Leon Avenue), San Juan, San Juan Municipio, PR

  19. ANALYSIS OF SWINE LAGOONS AND GROUND WATER FOR ENVIRONMENTAL ESTROGENS

    EPA Science Inventory

    A method was developed for analysis of low levels of natural (estradiol, estrone, estriol) and synthetic (ethinyl estradiol) estrogens in ground water and swine waste lagoon effluent. The method includes solid phase extraction of the estrogens, preparation of pentafluorobenzyl de...

  20. Arsenic pollution in Patos Lagoon estuarine sediments, Brazil.

    PubMed

    Mirlean, Nicolai; Andrus, Vlad E; Baisch, Paulo; Griep, Gilberto; Casartelli, Maria R

    2003-11-01

    Arsenic distribution in sediments of the Mirim-Patos lagoonal system is investigated. Deposits of fresh water Mirim Lagoon and those of the fresh water part of the Patos Lagoon contain 2.5 and 7.7 mg kg(-1), respectively, on average of total arsenic. In contrast, estuarine sediments of the Patos Lagoon are evidently contaminated by arsenic in high concentrations (up to 50 mg kg(-1)), and about 80% of the arsenic there is found in a bioavailable form. Analytical data coupled with direct, visual observations of estuarine water contamination by raw phosphorites and fertilizers suggest that the major source of arsenic in the estuarine sediments originated from the fertilizer industry.

  1. WISE Catches the Lagoon Nebula in Center of Action

    NASA Image and Video Library

    2011-01-06

    This colorful picture is a mosaic of Messier 8, or the Lagoon nebula, taken by NASA Wide-field Infrared Survey Explorer. This nebula is composed of clouds of gas and dust in which new stars are forming.

  2. Regulation of Methane Oxidation in a Freshwater Wetland by Water Table Changes and Anoxia

    NASA Technical Reports Server (NTRS)

    Roslev, Peter; King, Gary M.

    1996-01-01

    The effects of water table fluctuations and anoxia on methane emission and methane oxidation were studied in a freshwater marsh. Seasonal aerobic methane oxidation rates varied between 15% and 76% of the potential diffusive methane flux (diffusive flux in the absence of aerobic oxidation). On an annual basis, approximately 43% of the methane diffusing into the oxic zone was oxidized before reaching the atmosphere. The highest methane oxidation was observed when the water table was below the peat surface. This was confirmed in laboratory experiments where short-term decreases in water table levels increased methane oxidation but also net methane emission. Although methane emission was generally not observed during the winter, stems of soft rush (Juncus effusus) emitted methane when the marsh was ice covered. Indigenous methanotrophic bacteria from the wetiand studied were relatively anoxia tolerant. Surface peat incubated under anoxic conditions maintained 30% of the initial methane oxidation capacity after 32 days of anoxia. Methanotrophs from anoxic peat initiated aerobic methane oxidation relatively quickly after oxygen addition (1-7 hours). These results were supported by culture experiments with the methanotroph Methylosinus trichosporium OB3b. This organism maintained a greater capacity for aerobic methane oxidation when starved under anoxic compared to oxic conditions. Anoxic incubation of M. trichosporium OB3b in the presence of sulfide (2 mM) and a low redox potential (-110 mV) did not decrease the capacity for methane oxidation relative to anoxic cultures incubated without sulfide. The results suggest that aerobic methane oxidation was a major regulator of seasonal methane emission front the investigated wetland. The observed water table fluctuations affected net methane oxidation presumably due to associated changes in oxygen gradients. However, changes from oxic to anoxic conditions in situ had relatively little effect on survival of the methanotrophic

  3. Regulation of Methane Oxidation in a Freshwater Wetland by Water Table Changes and Anoxia

    NASA Technical Reports Server (NTRS)

    Roslev, Peter; King, Gary M.

    1996-01-01

    The effects of water table fluctuations and anoxia on methane emission and methane oxidation were studied in a freshwater marsh. Seasonal aerobic methane oxidation rates varied between 15% and 76% of the potential diffusive methane flux (diffusive flux in the absence of aerobic oxidation). On an annual basis, approximately 43% of the methane diffusing into the oxic zone was oxidized before reaching the atmosphere. The highest methane oxidation was observed when the water table was below the peat surface. This was confirmed in laboratory experiments where short-term decreases in water table levels increased methane oxidation but also net methane emission. Although methane emission was generally not observed during the winter, stems of soft rush (Juncus effusus) emitted methane when the marsh was ice covered. Indigenous methanotrophic bacteria from the wetiand studied were relatively anoxia tolerant. Surface peat incubated under anoxic conditions maintained 30% of the initial methane oxidation capacity after 32 days of anoxia. Methanotrophs from anoxic peat initiated aerobic methane oxidation relatively quickly after oxygen addition (1-7 hours). These results were supported by culture experiments with the methanotroph Methylosinus trichosporium OB3b. This organism maintained a greater capacity for aerobic methane oxidation when starved under anoxic compared to oxic conditions. Anoxic incubation of M. trichosporium OB3b in the presence of sulfide (2 mM) and a low redox potential (-110 mV) did not decrease the capacity for methane oxidation relative to anoxic cultures incubated without sulfide. The results suggest that aerobic methane oxidation was a major regulator of seasonal methane emission front the investigated wetland. The observed water table fluctuations affected net methane oxidation presumably due to associated changes in oxygen gradients. However, changes from oxic to anoxic conditions in situ had relatively little effect on survival of the methanotrophic

  4. Accumulation, Characterization, and Stabilization of Sludges for Cold Regions Lagoons

    DTIC Science & Technology

    1984-04-01

    aide If necesary and Identify by block number) Cold regions Lagoons Sanitary engineering Sewage Sludge 20 ASTIACT’ (CVtha sm etam aM N rnemind i...regions sludge accumulates during cold winter months but digests sufficiently during the warmer summer months to maintain the desired balance ...benthic sludge accumulation zone for only 2 to 4 months per year. If excess sludge in sewage lagoons is accumulating, then sludge volume and

  5. The future of methane

    SciTech Connect

    Howell, D.G.

    1995-12-31

    Natural gas, mainly methane, produces lower CO{sub 2}, CO, NO{sub x}, SO{sub 2} and particulate emissions than either oil or coal; thus further substitutions of methane for these fuels could help mitigate air pollution. Methane is, however, a potent greenhouse gas and the domestication of ruminants, cultivation of rice, mining of coal, drilling for oil, and transportation of natural gas have all contributed to a doubling of the amount of atmospheric methane since 1800. Today nearly 300,000 wells yearly produce ca. 21 trillion cubic feet of methane. Known reserves suggest about a 10 year supply at the above rates of recovery; and the potential for undiscovered resources is obscured by uncertainty involving price, new technologies, and environmental restrictions steming from the need to drill an enormous number of wells, many in ecologically sensitive areas. Until all these aspects of methane are better understood, its future role in the world`s energy mix will remain uncertain. The atomic simplicity of methane, composed of one carbon and four hydrogen atoms, may mask the complexity and importance of this, the most basic of organic molecules. Within the Earth, methane is produced through thermochemical alteration of organic materials, and by biochemical reactions mediated by metabolic processes of archaebacteria; some methane may even be primordial, a residue of planetary accretion. Methane also occurs in smaller volumes in landfills, rice paddies, termite complexes, ruminants, and even many humans. As an energy source, its full energy potential is controversial. Methane is touted by some as a viable bridge to future energy systems, fueled by the sun and uranium and carried by electricity and hydrogen.

  6. Methanation assembly using multiple reactors

    DOEpatents

    Jahnke, Fred C.; Parab, Sanjay C.

    2007-07-24

    A methanation assembly for use with a water supply and a gas supply containing gas to be methanated in which a reactor assembly has a plurality of methanation reactors each for methanating gas input to the assembly and a gas delivery and cooling assembly adapted to deliver gas from the gas supply to each of said methanation reactors and to combine water from the water supply with the output of each methanation reactor being conveyed to a next methanation reactor and carry the mixture to such next methanation reactor.

  7. Site specific diel methane emission mechanisms in landfills: A field validated process based on vegetation and climate factors.

    PubMed

    Xin, Danhui; Hao, Yongxia; Shimaoka, Takayuki; Nakayama, Hirofumi; Chai, Xiaoli

    2016-11-01

    Diel methane emission fluxes from a landfill that was covered by vegetation were investigated to reveal the methane emission mechanisms based on the interaction of vegetation characteristics and climate factors. The methane emissions showed large variation between daytime and nighttime, and the trend of methane emissions exhibited clear bimodal patterns from both Setaria viridis- and Neyraudia reynaudiana-covered areas. Plants play an important role in methane transportation as well as methane oxidation. The notable decrease in methane emissions after plants were cut suggests that methane transportation via plants is the primary way of methane emissions in the vegetated areas of landfill. Within plants, the methane emission fluxes were enhanced due to a convection mechanism. Given that the methane emission flux is highly correlated with the solar radiation during daytime, the convection mechanism could be attributed to the increase in solar radiation. Whereas the methane emission flux is affected by a combined impact of the wind speed and pedosphere characteristics during nighttime. An improved understanding of the methane emission mechanisms in vegetated landfills is expected to develop a reliable model for landfill methane emissions and to attenuate greenhouse gas emissions from landfills.

  8. Tidal dynamics in a frictionally dominated tropical lagoon

    NASA Astrophysics Data System (ADS)

    Tenorio-Fernandez, L.; Gomez-Valdes, J.; Marino-Tapia, I.; Enriquez, C.; Valle-Levinson, A.; Parra, S. M.

    2016-02-01

    This study examined the dynamics of tidal propagation inside a tropical lagoon. Sea surface elevation (inside) and current profiles (at the inlet) were examined over 60 days at the Chelem lagoon, which is a branched tropical lagoon located in the northern Yucatan Peninsula. Tides were predominantly diurnal with a wavelength at least 20 times longer than the total length of the basin. Spatial variations of sea surface elevation and the longitudinal transport were described in each branch by applying a linear analytical model and the results were compared to observations. Results showed that the coastal lagoon was highly frictional. The tidal signal was attenuated between 30% and 40% toward the lagoon heads, a result of the balance between pressure gradient and frictional forces. A causeway that chokes the western side of the lagoon allowed the propagation of the diurnal signal toward the west head of the basin but damped the semidiurnal signal. The causeway acted as a hydraulic low-pass filter, as in natural choked systems. The causeway's filter effect was included in the analytical model by optimizing the frictional parameters.

  9. Chamber-Based Estimates of Methane Production in Coastal Estuarine Systems in Southern California

    NASA Astrophysics Data System (ADS)

    Brigham, B.; Lipson, D.; Lai, C.

    2008-12-01

    Wetland systems are believed to produce between 100 - 231 Tg CH4 yr-1 which is roughly 20% of global methane emissions. The uncertainty in methane emissions models stem from the lack of detailed information about methane gas production within regional wetland systems. The aim of this study is to report the range of methane fluxes observed along salinity gradients at two San Diego coastal wetland systems, the Tijuana Estuary (Tijuana River National Estuarine Research Reserve) and the Peñasquitos Lagoon (Torrey Pines State Park Reserve). Soil water samples are used to elucidate factors responsible for the observed variation in methane fluxes. Air samples were subsequently collected from the headspace of a static soil chamber and stored in pre- evacuated vials. Methane concentrations were analyzed within hours after collection by gas chromatography in the laboratory. The chemical and physical properties of the soil, including salinity, pH, redox potential and temperature are measured with a hand-held probe nearby soil collars. The biological properties of the soil, including dissolved organic carbon, nitrate, and ammonia levels are measured from soil water samples in the laboratory. We find that saline sites under direct tidal influence produced methane fluxes ranging from -3.10 to 9.10 (mean 2.18) mg CH4 m-2 day-1. We also find that brackish sites (0.6 to 3.2 ppt in salinity) with fresh water input from residential runoff at the Peñasquitos Lagoon produced methane fluxes ranging from 0.53 to 192.10 (mean 33.34) mg CH4 m-2 day-1. Sampling was done over the course of 5 weeks during August-September of 2008. We hypothesize that the contrasting methane fluxes found between the saline and the brackish sites is due primarily to the different salinity, and in turn sulfate levels found at the two sites. The reduction of sulfate to produce energy is more energetically favorable than the reduction of carbon dioxide to produce methane. Thus the presence of sulfate may act as

  10. Masterplan to safeguard Venice and to restore the lagoon and conterminous areas

    NASA Astrophysics Data System (ADS)

    Bini, Claudio; Gallo, Alba; Nadimi-Goki, Mandana; Wahsha, Mohammad

    2015-04-01

    Venice and its lagoon constitute a complex system, well known all over the world for the peculiarity of the town and for the fragility of the lagoon ecosystem with its delicate equilibrium. The whole system has been, and is currently, affected by human activities (industry, agriculture, settlements, tourism) that impact severely the ecosystem. Discharge from the agricultural drainage basin affects particularly the area North of the city of Venice; the central and southern areas, instead, receive important pollutant inputs from the industrial zone of Porto Marghera since the early'50s. Additional sources of pollution are domestic sewage and waste disposal from the urban area, that is visited by more than 10M people every year. As a consequence of the increasing land contamination, significant amounts of contaminants (both organic and inorganic) are accumulated in soils of the borderline, in water and in lagoon sediments, which constitute a potential source of secondary pollution. Results of surveys carried out in recent years in the whole area show that contaminants concentration increased from the beginning of the industrial activities until the '90s, when Porto Marghera declined. Most of contaminants have concentrations above the background levels. The highest metal levels were found in an area between Porto Marghera and the city of Venice, where both industrial and urban sewage are discharged, provoking environmental and human health hazard. In order to safeguard the city of Venice, and to restore its lagoon and conterminous areas, a Master Plan of intervention has been developed since the early 2000s. The land currently interested by environmental analysis and/or restoration covers approximately 1350ha; 78% of these (1100ha) proved variously contaminated, with 85% of sites overcoming the National Reference Values. Contamination, besides being diffused, is quite complex, involving the co-existence of several contaminant families (PAH, PCB, dioxin, heavy metals

  11. Pathways of priority pesticides in sediments of coastal lagoons: The case study of Óbidos Lagoon, Portugal.

    PubMed

    Pinto, M I; Vale, C; Sontag, G; Noronha, J P

    2016-05-15

    This study reports the concentrations of the priority pesticides (PPs) in 14 surface sediments and 21 layers of a sediment core from Óbidos Lagoon, a shallow Portuguese coastal lagoon. Results show that the PPs are confined to the upper part of the lagoon that receives most of the inputs from surface runoff of the surrounding agricultural fields and from small tributaries. Past and recent applied PPs were registered in sediments, aluminum normalized concentrations varying between 0.05×10(-7) and 6.85×10(-7). The PP risk assessment based on sediment quality guidelines like the "Probable Effect Level" (PEL) shows no biological effects in either sediments or aquatic organisms of Óbidos Lagoon, except for dieldrin, lindane, DDT, heptachlor epoxide and its parent compound heptachlor. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Assessing the impact of dairy waste lagoons on groundwater quality using a spatial analysis of vadose zone and groundwater information in a coastal phreatic aquifer.

    PubMed

    Baram, S; Kurtzman, D; Ronen, Z; Peeters, A; Dahan, O

    2014-01-01

    Dairy waste lagoons are considered to be point sources of groundwater contamination by chloride (Cl(-)), different nitrogen-species and pathogens/microorganisms. The objective of this work is to introduce a methodology to assess the past and future impacts of such lagoons on regional groundwater quality. The method is based on a spatial statistical analysis of Cl(-) and total nitrogen (TN) concentration distributions in the saturated and the vadose (unsaturated) zones. The method provides quantitative data on the relation between the locations of dairy lagoons and the spatial variability in Cl(-) and TN concentrations in groundwater. The method was applied to the Beer-Tuvia region, Israel, where intensive dairy farming has been practiced for over 50 years above the local phreatic aquifer. Mass balance calculations accounted for the various groundwater recharge and abstraction sources and sinks in the entire region. The mass balances showed that despite the small surface area covered by the dairy lagoons in this region (0.8%), leachates from lagoons have contributed 6.0% and 12.6% of the total mass of Cl(-) and TN (mainly as NO3(-)-N) added to the aquifer. The chemical composition of the aquifer and vadose zone water suggested that irrigated agricultural activity in the region is the main contributor of Cl(-) and TN to the groundwater. A low spatial correlation between the Cl(-) and NO3(-)-N concentrations in the groundwater and the on-land location of the dairy farms strengthened this assumption, despite the dairy waste lagoon being a point source for groundwater contamination by Cl(-) and NO3(-)-N. Mass balance calculations, for the vadose zone of the entire region, indicated that drying of the lagoons would decrease the regional groundwater salinization process (11% of the total Cl(-) load is stored under lagoons). A more considerable reduction in the groundwater contamination by NO3(-)-N is expected (25% of the NO3(-)-N load is stored under lagoons). Results

  13. Development of highly sensitive sensor system for methane utilizing cataluminescence.

    PubMed

    Gong, Gu; Zhu, Hua

    2016-02-01

    A gaseous sensor system was developed for the detection of methane based on its cataluminescence emission. Cataluminescence characteristics and optimal conditions were studied in detail under optimized experimental conditions. Results showed that the methane cataluminescence sensor system could cover a linear detection range from 10 to 5800 ppm (R = 0.9963, n = 7) and the detection limit was about 7 ppm (S/N = 3), which was below the standard permitted concentration. Moreover, a linear discriminant analysis method was used to test the recognizable performance of the methane sensor. It was found that methane, ethane, propane and pentane could be distinguished clearly. Its methane sensing properties, including improved sensitivity, selectivity, stability and recognition demonstrated the TiO2/SnO2 materials to be promising candidates for constructing a cataluminescence-based gas sensor that could be used for detecting explosive gas contaminants.

  14. Geoengineering treatment of methane

    NASA Astrophysics Data System (ADS)

    Lockley, Andrew; Gardian, Alan

    2010-05-01

    Methane is a significant GHG, and substantial reservoirs are vulnerable to instability due to AGW. Excursions, from permafrost and clathrates especially, act a positive feedback to AGW. Existing concentrations of well-mixed atmospheric methane substantially exceed pre-industrial levels. Various geoengineering methods are herein proposed for containment of methane, and/or accelerated oxidation to CO2 (a gas with a lower GWP over all timescales). A basic qualitative analysis of each technique is undertaken, to direct further study. Consideration is also given to the potential capacity of each technique to treat the total likely excursions of methane expected as a result of AGW. Proposed techniques: Section 0 SRM (comparison option) Section 1 Pre-emptive treatment of methane reservoirs Soil heating (polytunnels, heat pumps); Soil aeration; Mining of clathrates; Burning of clathrates Section 2 Remediation of aquatic methane excursions Lake sealing; Mixing of aquatic strata; Bubble capture; Lake aeration; Biological oxidation in aquatic environments Section 3 Remediation of concentrated atmospheric methane Regenerative thermal oxidation; Electrical ignition; Thermal ignition; Using incendiary munitions Section 4 Remediation of diffuse atmospheric methane Thermal oxidation by concentrated solar power; Compression ignition; Chemical degradation Assessment criteria: Infrastructure/implementation cost; Energy cost; Expected efficacy; Complexity/development path; Environmental impacts; Potential for CCS

  15. Optimal sensor locations for the backward lagrangian stochastic technique in measuring lagoon gas emission.

    PubMed

    Ro, Kyoung S; Stone, Kenneth C; Johnson, Melvin H; Hunt, Patrick G; Flesch, Thomas K; Todd, Richard W

    2014-07-01

    This study evaluated the impact of gas concentration and wind sensor locations on the accuracy of measuring gas emission rates from a lagoon environment using the backward Lagrangian stochastic (bLS) inverse-dispersion technique. Path-integrated concentrations (PICs) and three-dimensional (3D) wind vector data were collected at different locations within the lagoon landscape. A floating 45 m × 45 m perforated pipe network on an irrigation pond was used as a synthetic distributed emission source for the controlled release of methane. A total of 961 15-min datasets were collected under different atmospheric stability conditions over a 2-yr period. The PIC location had a significant impact on the accuracy of the bLS technique. The location of the 3D sonic anemometer was generally not a factor for the measured accuracies with the PIC positioned on the downwind berm. The PICs across the middle of the pond consistently produced the lowest accuracy with any of the 3D anemometer locations (<69% accuracy). The PICs located on the downwind berm consistently yielded the best bLS accuracy regardless of whether the 3D sonic anemometer was located on the upwind, side, or downwind berm (accuracies ranged from 79 to 108%). The accuracies of the emission measurements with the berm PIC-berm 3D setting were statistically similar to that found in a more ideal homogeneous grass field. Considering the practical difficulties of setting up equipment and the accuracies associated with various sensor locations, we recommend that wind and concentration sensors be located on the downwind berm.

  16. Landfill Gas Effects on Evapotranspirative Landfill Covers

    NASA Astrophysics Data System (ADS)

    Plummer, M. A.; Mattson, E.; Ankeny, M.; Kelsey, J.

    2005-05-01

    The performance of an evapotranspirative landfill cover can be adversely affected by transport of landfill gases to the plant root zone. Healthy plant communities are critical to the success and effectiveness of these vegetated landfill covers. Poor vegetative cover can result in reduced transpiration, increased percolation, and increased erosion regardless of the thickness of the cover. Visual inspections of landfill covers indicate that vegetation-free areas are not uncommon at municipal waste landfills. Data from soil profiles beneath these areas suggest that anaerobic conditions in the plant-rooting zone are controlling plant distribution. On the same landfill, aerobic conditions exist at similar depths beneath well-vegetated areas. The movement of methane and carbon dioxide, generated by degradation of organic wastes, into the overlying soil cover displaces oxygen in the root zone. Monitoring data from landfills in semi-arid areas indicate that barometric pumping can result in hours of anaerobic conditions in the root zone. Microbial consumption of oxygen in the root zone reduces the amount of oxygen available for plant root respiration but consumption of oxygen and methane also produce water as a reaction byproduct. This biogenic water production can be on the order of centimeters of water per year which, while increasing water availability, also has a negative feedback on transport of landfill gases through the cover. Accounting for these processes can improve evapotranspirative landfill cover design at other sites.

  17. Radiological impact of phosphogypsum discharged into the Venice lagoon: 222Rn

    NASA Astrophysics Data System (ADS)

    Cantaluppi, C.; Ceccotto, F.; Cianchi, A.; Fasson, A.; Degetto, S.

    2012-04-01

    For about 20 years, between the 60 's and the 80 's of the last century, in the Passo a Campalto area (Lagoon of Venice - Italy) about 400,000 m3 of phosphogypsum (PG) were deposited at the border of the lagoon and next to urban areas without any environmental control. These materials are a by-product formed during the wet processing of phosphate rocks by sulphuric acid and have a significant environmental impact due to their abundance and their chemical-physical and radiochemical characteristics. The PG contains both chemical elements, which are considered dangerous for the ecosystems and natural radionuclides whose concentrations are much higher if compared to those typical for the Earth's crust. These discarded materials caused for many years the dispersion of radionuclides in the environment due to the tidal erosion, the re-suspension of radioactive inhalable dusts, the uncontrolled radon exhalation and the bioaccumulation of some radionuclides in the lagoon environment. After a decision of the appointed authorities, the Venice Water Authority (Ministry of Infrastructure and Transport), planned a permanent safety control of the site resulting in the complete isolation of the entire volume of contaminated materials from the environmental system. The entire project was specific for the particular features of the site and it required the improvement of analytical, sampling and measurement techniques in order to verify the effectiveness of the safety action. The radon assessment, in particular the check of the effectiveness of the inhibition of radon exhalation, is part of a more complex study, covering many other aspects of the management of a permanent disposal; they will be the object of further notes. The ultimate results of this study prove the efficacy of the intervention: radon concentrations in air and exhalation values from the restored area, measured during surveys, have been proved to be well in agreement with those of non contaminated soils.

  18. Multivariate Statistical Analysis of Water Quality data in Indian River Lagoon, Florida

    NASA Astrophysics Data System (ADS)

    Sayemuzzaman, M.; Ye, M.

    2015-12-01

    The Indian River Lagoon, is part of the longest barrier island complex in the United States, is a region of particular concern to the environmental scientist because of the rapid rate of human development throughout the region and the geographical position in between the colder temperate zone and warmer sub-tropical zone. Thus, the surface water quality analysis in this region always brings the newer information. In this present study, multivariate statistical procedures were applied to analyze the spatial and temporal water quality in the Indian River Lagoon over the period 1998-2013. Twelve parameters have been analyzed on twelve key water monitoring stations in and beside the lagoon on monthly datasets (total of 27,648 observations). The dataset was treated using cluster analysis (CA), principle component analysis (PCA) and non-parametric trend analysis. The CA was used to cluster twelve monitoring stations into four groups, with stations on the similar surrounding characteristics being in the same group. The PCA was then applied to the similar groups to find the important water quality parameters. The principal components (PCs), PC1 to PC5 was considered based on the explained cumulative variances 75% to 85% in each cluster groups. Nutrient species (phosphorus and nitrogen), salinity, specific conductivity and erosion factors (TSS, Turbidity) were major variables involved in the construction of the PCs. Statistical significant positive or negative trends and the abrupt trend shift were detected applying Mann-Kendall trend test and Sequential Mann-Kendall (SQMK), for each individual stations for the important water quality parameters. Land use land cover change pattern, local anthropogenic activities and extreme climate such as drought might be associated with these trends. This study presents the multivariate statistical assessment in order to get better information about the quality of surface water. Thus, effective pollution control/management of the surface

  19. Metagenomics-based analysis of viral communities in dairy lagoon wastewater.

    PubMed

    Alhamlan, F S; Ederer, M M; Brown, C J; Coats, E R; Crawford, R L

    2013-02-15

    Microbial populations, especially those of viruses, are poorly studied in dairy wastewater treatment operations. Here we report signature nucleic acid metagenomic sequences obtained by pyrosequencing viromes of virus-like particles that were extracted from two dairy waste treatment lagoons. The lagoons are operated in series, with Lagoon I being used as the primary stage and Lagoon II as the secondary stage of wastewater treatment. An average of 2000 sequences was obtained from each lagoon. More than 300 signatures from each lagoon matched sequences in the virus database of the National Center for Biotechnology Information (NCBI). We utilized a bioinformatics approach and transmission electron microscopy (TEM) to characterize the viral diversity and presence of potential viral pathogens within the lagoons. Our results showed differences in viral community compositions between Lagoon I and Lagoon II, suggesting that the viral community changes significantly in the transition of water between the two lagoons. Furthermore, the diverse viral community in the lagoon samples contained signature sequences of a variety of bacterial, plant, and animal viruses. Bacteriophage sequences dominated the viral community metagenomes in both lagoons. Ultimately these results can be used to identify viral bioindicators to rapidly assess wastewater treatment quality and the potential impacts of dairy operations on watersheds. Our viral metagenomic sequences have been submitted to GenBank (GPID 65805) and can provide insight into the composition and structure of viral communities within wastewaters of dairy lagoon systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Comparative hydrodynamics of 10 Mediterranean lagoons by means of numerical modeling

    NASA Astrophysics Data System (ADS)

    Umgiesser, Georg; Ferrarin, Christian; Cucco, Andrea; De Pascalis, Francesca; Bellafiore, Debora; Ghezzo, Michol; Bajo, Marco

    2014-04-01

    A comparison study between 10 Mediterranean lagoons has been carried out by means of the 3-D numerical model SHYFEM. The investigated basins are the Venice and Marano-Grado lagoons in the Northern Adriatic Sea, the Lesina and Varano lagoons in the Southern Adriatic Sea, the Taranto basin in the Ionian Sea, the Cabras Lagoon in Sardinia, the Ganzirri and Faro lagoons in Sicily, the Mar Menor in Spain, and the Nador Lagoon in Morocco. This study has been focused on hydrodynamics in terms of exchange rates, transport time scale, and mixing. Water exchange depends mainly on the inlet shape and tidal range, but also on the wind regimes in the case of multi-inlet lagoons. Water renewal time, which is mostly determined by the exchange rate, is a powerful concept that allows lagoons to be characterized with a time scale. In the case of the studied lagoons, the renewal time ranged from few days in the Marano-Grado Lagoon up to 1 year in the case of the Mar Menor. The analysis of the renewal time frequency distribution allows identifying subbasins. The numerical study proved to be a useful tool for the intercomparison and classification of the lagoons. These environments range from a leaky type to a choked type of lagoons and give a representative picture of the lagoons situated around the Mediterranean basin. Mixing efficiency turns out to be a function of the morphological complexity, but also of the forcings acting on the system.

  1. Land cover

    USGS Publications Warehouse

    Jorgenson, Janet C.; Joria, Peter C.; Douglas, David C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Documenting the distribution of land-cover types on the Arctic National Wildlife Refuge coastal plain is the foundation for impact assessment and mitigation of potential oil exploration and development. Vegetation maps facilitate wildlife studies by allowing biologists to quantify the availability of important wildlife habitats, investigate the relationships between animal locations and the distribution or juxtaposition of habitat types, and assess or extrapolate habitat characteristics across regional areas.To meet the needs of refuge managers and biologists, satellite imagery was chosen as the most cost-effective method for mapping the large, remote landscape of the 1002 Area.Objectives of our study were the following: 1) evaluate a vegetation classification scheme for use in mapping. 2) determine optimal methods for producing a satellite-based vegetation map that adequately met the needs of the wildlife research and management objectives; 3) produce a digital vegetation map for the Arctic Refuge coastal plain using Lands at-Thematic Mapper(TM) satellite imagery, existing geobotanical classifications, ground data, and aerial photographs, and 4) perform an accuracy assessment of the map.

  2. The freshwater artisanal fishery of Patos Lagoon.

    PubMed

    Ceni, G; Fontoura, N F; Cabral, H N

    2016-07-01

    In this study data relative to the fishery in the freshwater area of the Patos Lagoon are analysed, and the dynamics, fishing gears used and catches evaluated. The results reveal the existence of two fishery strategies: forbidden mesh size gillnets (FMG; <35 mm; square measure) and allowed mesh size gillnets (AMG; ≥35 mm; square measure). In total, 31 species were caught (AMG = 27 and FMG = 24), but selectivity due to mesh size was significant (P < 0·001). The FMG may be very harmful since it captures individuals of most species below size at first maturity, including the target species, the armoured catfish Loricariichthys anus (61% of the total catch). In addition, this gear is used throughout the year, including the closed season (CS; November to January), when the target species is reproducing. Target species for the AMG are larger in size, comprising mainly the mullet Mugil liza, the marine catfish Genidens barbus and the whitemouth croaker Micropogonias furnieri. AMS gillnets were not used during the CS. The use of FMG reveals the need for effective fishery law enforcement and the need for additional studies to assess the status of populations of the exploited species. © 2016 The Fisheries Society of the British Isles.

  3. Central Facilities Area Sewage Lagoon Evaluation

    SciTech Connect

    Mark R. Cole

    2013-12-01

    The Central Facilities Area (CFA), located in Butte County, Idaho, at the Idaho National Laboratory has an existing wastewater system to collect and treat sanitary wastewater and non-contact cooling water from the facility. The existing treatment facility consists of three cells: Cell #1 has a surface area of 1.7 acres, Cell #2 has a surface area of 10.3 acres, and Cell #3 has a surface area of 0.5 acres. If flows exceed the evaporative capacity of the cells, wastewater is discharged to a 73.5-acre land application site that uses a center-pivot irrigation sprinkler system. As flows at CFA have decreased in recent years, the amount of wastewater discharged to the land application site has decreased from 13.64 million gallons in 2004 to no discharge in 2012 and 2013. In addition to the decreasing need for land application, approximately 7.7 MG of supplemental water was added to the system in 2013 to maintain a water level and prevent the clay soil liners in the cells from drying out and “cracking.” The Idaho National Laboratory is concerned that the sewage lagoons and land application site may be oversized for current and future flows. A further concern is the sustainability of the large volumes of supplemental water that are added to the system according to current operational practices. Therefore, this study was initiated to evaluate the system capacity, operational practices, and potential improvement alternatives, as warranted.

  4. Methane Emission by Camelids

    PubMed Central

    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

  5. Methane emission by camelids.

    PubMed

    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.

  6. Mapping Pluto Methane Ice

    NASA Image and Video Library

    2015-09-24

    The Ralph/LEISA infrared spectrometer on NASA's New Horizons spacecraft mapped compositions across Pluto's surface as it flew past the planet on July 14, 2015. On the left, a map of methane ice abundance shows striking regional differences, with stronger methane absorption indicated by the brighter purple colors, and lower abundances shown in black. Data have only been received so far for the left half of Pluto's disk. At right, the methane map is merged with higher-resolution images from the spacecraft's Long Range Reconnaissance Imager (LORRI). http://photojournal.jpl.nasa.gov/catalog/PIA19953

  7. Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

    2015-12-01

    Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

  8. Spatial variation in recruitment of native and invasive sessile species onto oyster reefs in a temperate soft-bottom lagoon

    NASA Astrophysics Data System (ADS)

    Thomsen, M. S.; Silliman, B. R.; McGlathery, K. J.

    2007-03-01

    Although spatial variability in recruitment is a strong force structuring many marine communities, relatively few data exist on recruitment variability in sessile oyster reef communities. In a soft-bottom lagoon in Virginia, we tested if recruitment differed among three reefs situated across a mainland-lagoon-barrier-island transect and among elevations (>90-80, >80-70, >70-55 and >55-20 cm below MSL) on the lagoon reef. The most abundant taxa (the invasive algae Gracilaria vermiculophylla and Codium fragile and the indigenous oyster Crassostrea virginica and algae Ulva curvata) had highest recruitment at the lagoon reef, where propagule supply was likely highest. The mainland reef had lowest algal richness (1.4-3.1 panel -1) and abundances (<4% cover) compared to lagoon and island reefs (3.3-6.5 panel -1, 14-20%), but there were no differences between sites for animals. Overall, animals and algae were equally dominant at the mainland reef, whereas algae dominated at lagoon and island reefs. High water turbidity and suspended solids are typical algal stressors at mainland reefs, and these may account for the low algal abundance in that region. For many species (at least 9 out of 14) differences in recruitment success were observed over elevation differences as small as 10-30 cm, e.g. G. vermiculophylla and C. fragile mainly recruited up to >70-55 and >80-70 cm respectively (probably limited upward by desiccation), U. curvata down to >70-55 cm (probably limited downward by grazing or competition), whereas C. virginica recruited at all elevations. Animal richness was highest at the two lowest elevations (2.0-2.5 vs. 1.1-1.8 panel -1), but there was no effect of elevation on algae (3-6 panel -1) because of species substitutions between elevation levels. Thus, as in rocky intertidal systems, spatial variability in recruitment is important for community structure on oyster reefs, and if biodiversity is considered an important reef conservation goal, managers should

  9. Silica in invasive wetland plant species of lagoons, Côte d'Ivoire: Spatio-temporal patterns

    NASA Astrophysics Data System (ADS)

    José-mathieu Koné, Yéfanlan; Schoelynck, Jonas

    2017-04-01

    Tropical wetlands are known to accumulate a large quantity of Biogenic Silica (BSi) produced by wetland plant species (Struyf et al., 2015), and approximately 70-80% of the total supply of Dissolved Si (DSi) to the coastal zone occurs in (sub) tropical river systems (Jennerjahn et al. 2006). However, the data at these latitudes are limited. Here, we present the BSi concentration from eleven invasive macrophyte species randomly collected in three small ( 800ha) lagoons of Côte d'Ivoire during 12 months. Our data showed a large spatio-temporal variability of BSi in the three lagoons with no consistent trends. In general, the BSi concentrations obtained were high and values ranged from 0 to 54 mg g-1 through the entire sampling period, with the highest values found in Acroceras zizaniodes (emergent species of Poaceae). In general, free floating species had significantly less BSi than emergent species (P<0.0001) which corroborates with the earlier findings of Schoelynck and Struyf (2016). However, the concentrations of BSi found in Salvinia molesta (a free floating species of fern, Salviniaceae) at the young stage were similar to those found in the emergent species. Based on yearly averages, highest BSi values were observed in Kodjoboué lagoon, and the lowest in the Ono lagoon that is 80% covered by macrophytes. Moreover, the dissolved silica (DSi) concentrations were systematically higher in Ono Lagoon than in Kodjoboué Lagoon. We conclude that in an eutrophic system Si accumulating in aquatic macrophytes is not related to Si availability but to other environmental factors. Jennerjahn, T.C., Knoppers, B.A., de Souze, W.F.L., Brunskill, G.J., Silva, E.I.L., Adi, S. et al., 2006. Factors controlling dissolved silica in tropical rivers. In: Ittekot, V. (ed) The silicon cycle. Island Press, Washington, D. C, pp 29-51 Schoelynck J and Struyf E, 2016. Silicon in aquatic vegetation. Functional Ecology. 30: 1323-1330. Struyf, E., Mosimane, K., Van Pelt, D., Murray

  10. Geochemical characterization of seaplane lagoon sediments, Alameda Naval Air Station

    SciTech Connect

    Bono, A; Carroll, S; Esser, B; Luther, G W; O'Day, P; Randall, S

    1999-08-16

    Our objective in the characterization of sediments from Seaplane Lagoon at the Alameda Naval Air Station (NAS) was to determine the geochemical interactions that control the partitioning of cadmium, chromium, cobalt, copper, lead, mercury, nickel, and zinc between the sediments and the porewaters. Our approach was to collect several cores at the east outfall location of the Seaplane Lagoon. We determined the porewater chemistry by (1) making in situ micro-electrode measurements, (2) extracting porewaters, and (3) modeling geochemical reactions. We determined the sediment chemistry by measuring (1) elemental abundance, (2) mineralogy, and (3) trace-element speciation. This information should help the US Navy determine the long-term hazard of the sediments if they are left in place and the short-term hazard if they are dredged. We did not fully examine the geochemistry of sediments from the West Beach Landfill Wetlands site, because these sediments were distinct from the Seaplane Lagoon sediments. Our initial motivation for studying the Landfill Wetlands site was to determine the trace-element geochemistry in Seaplane Lagoon sediments that had been dredged and then disposed in the Landfill Wetlands. Unfortunately, the location of these dredged sediments is unknown. The cores we sampled were not from the Seaplane Lagoon.

  11. Factors Controlling the Morphodynamics of a Tropical Coastal Lagoon.

    NASA Astrophysics Data System (ADS)

    Enriquez, C.; Marino-Tapia, I.

    2016-02-01

    Celestun is a large (22 km) and elongated (north-south axis) tropical coastal lagoon known for its beauty and biodiversity, but its morphology has been artificially altered by an embankment road built to provide access to the coastal town. This road divided the lagoon by the middle nearly blocking the communication and heavily altering the hydrodynamics. Since then, the head has a restricted circulation (hence higher residence time) and accretion processes have modified the flows affecting the water quality and the tidal flooding towards the wetland and mangrove regions surrounding the lagoon. In this study a morphodynamic process-based numerical model (DELFT3D) is used to investigate the hydro and morphodynamics of Celestun resulting from various meteorological and oceanographic forcings and under different scenarios of anthropogenic alterations (i.e. with and without the road). The coastal lagoon receives important submarine groundwater discharges and therefore the influence of density gradients in the system dynamics is also studied. Results show that the tides control the instantaneous hydrodynamic characteristics but the continental water discharges through SGDs and their variations dominate the morphodynamics in relation to the channel development and evolution. The embankment road restricts the flow to the upper half of the lagoon, minimizing the water circulation at the head, and modifies the circulation patterns creating a large region of accretion in the south near the road.

  12. Fine and coarse components in surface sediments from Bikini Lagoon

    SciTech Connect

    Noshkin, V. E., LLNL

    1997-01-01

    In 1979, 21 years after the moratorium on nuclear testing in the Marshall Islands, surface sediment samples (to depths of 2 and 4 cm) were collected from 87 locations in the lagoon of Bikini Atoll, one of the two sites in the Marshall Islands used by the United States to test nuclear devices from 1946 through 1958. The main purpose for the collections was to map the distribution of long-lived man-made radionuclides associated with the bottom material. In addition the samples were processed to estimate the fraction of fine and coarse components to show, by comparison, what modifications occurred in the composition since the sediments were first described in samples collected before testing in 1946. Nuclear testing produced more finely divided material that is now found in the surface sediment layer over large areas of the lagoon and especially in regions of the lagoon and reef adjacent to test sites. The 5 cratering events alone at Bikini Atoll redistributed sufficient material to account for the higher inventory of fine material found over the surface 4 cm of the sediment of the lagoon. Although the fraction of fine material in the bottom sediments was altered by the nuclear events, the combined processes of formation, transport and deposition were not sufficiently dynamic to greatly change the general geographical features of the major sedimentary components over most of the lagoon floor.

  13. Phytoplankton assemblages in lateral lagoons of a large tropical reservoir.

    PubMed

    Ferrareze, M; Nogueira, M G

    2013-02-01

    This study aimed to analyse the composition and ecological attributes of the phytoplankton assemblages in four lateral lagoons and in the main channel of Rosana Reservoir (Paranapanema River, SE Brazil). Fieldwork was carried out in September and November/2004 and January, March, May and August/2005. A total of 283 taxa was identified. Zygnemaphyta was the most specious group, followed by Chlorophyta and Bacillariophyta. Higher richness, abundance and biomass were observed in the lagoons when compared with the river-reservoir sampling point, especially during the rainy period. Cryptophyceae and Bacillariophyceae dominated numerically. Cryptomonas brasiliensis Castro, Bicudo and Bicudo was the main species of the phytoplankton in terms of abundance and frequency of occurrence. The dynamics of the most important taxa are discussed and the results showed that the phytoplankton assemblages are mainly influenced by meteorological factors and nutrient availability (the main driving forces). Correlation analyses indicated that the assemblage abundance was limited by nutrient (nitrogen and phosphorus). The phytoplankton abundance influenced positively the zooplankton abundance, what indicates the prevalence of bottom-up control routes in the lateral lagoons system. The results validate the hypotheses that lateral lagoons have a prominent ecological role on the phytoplankton diversity, as already previously demonstrated for fish and zooplankton. Therefore, the incorporation of the lateral lagoons in environmental programmes should be a target strategy for the conservation of the regional aquatic biota, minimising the negative impact of the dam.

  14. Earthworm activity in a simulated landfill cover soil shifts the community composition of active methanotrophs.

    PubMed

    Kumaresan, Deepak; Héry, Marina; Bodrossy, Levente; Singer, Andrew C; Stralis-Pavese, Nancy; Thompson, Ian P; Murrell, J Colin

    2011-12-01

    Landfills represent a major source of methane in the atmosphere. In a previous study, we demonstrated that earthworm activity in landfill cover soil can increase soil methane oxidation capacity. In this study, a simulated landfill cover soil mesocosm (1 m × 0.15 m) was used to observe the influence of earthworms (Eisenia veneta) on the active methanotroph community composition, by analyzing the expression of the pmoA gene, which is responsible for methane oxidation. mRNA-based pmoA microarray analysis revealed that earthworm activity in landfill cover soil stimulated activity of type I methanotrophs (Methylobacter, Methylomonas, Methylosarcina spp.) compared to type II methanotrophs (particularly Methylocystis spp.). These results, along with previous studies of methanotrophs in landfill cover soil, can now be used to plan in situ field studies to integrate earthworm-induced methanotrophy with other landfill management practises in order to maximize soil methane oxidation and reduce methane emissions from landfills.

  15. Stabilization of methane hydrate by pressurization with He or N2 gas.

    PubMed

    Lu, Hailong; Tsuji, Yoshihiro; Ripmeester, John A

    2007-12-27

    The behavior of methane hydrate was investigated after it was pressurized with helium or nitrogen gas in a test system by monitoring the gas compositions. The results obtained indicate that even when the partial pressure of methane gas in such a system is lower than the equilibrium pressure at a certain temperature, the dissociation rate of methane hydrate is greatly depressed by pressurization with helium or nitrogen gas. This phenomenon is only observed when the total pressure of methane and helium (or nitrogen) gas in the system is greater than the equilibrium pressure required to stabilize methane hydrate with just methane gas. The following model has been proposed to explain the observed phenomenon: (1) Gas bubbles develop at the hydrate surface during hydrate dissociation, and there is a pressure balance between the methane gas inside the gas bubbles and the external pressurizing gas (methane and helium or nitrogen), as transmitted through the water film; as a result the methane gas in the gas bubbles stabilizes the hydrate surface covered with bubbles when the total gas pressure is greater than the equilibrium pressure of the methane hydrate at that temperature; this situation persists until the gas in the bubbles becomes sufficiently dilute in methane or until the surface becomes bubble-free. (2) In case of direct contact of methane hydrate with water, the water surrounding the hydrate is supersaturated with methane released upon hydrate dissociation; consequently, methane hydrate is stabilized when the hydrostatic pressure is above the equilibrium pressure of methane hydrate at a certain temperature, again until the dissolved gas at the surface becomes sufficiently dilute in methane. In essence, the phenomenon is due to the presence of a nonequilibrium state where there is a chemical potential gradient from the solid hydrate particles to the bulk solution that exists as long as solid hydrate remains.

  16. A 7500-year strontium isotope record from the northwestern Nile delta (Maryut lagoon, Egypt)

    NASA Astrophysics Data System (ADS)

    Flaux, Clément; Claude, Christelle; Marriner, Nick; Morhange, Christophe

    2013-10-01

    During the Holocene, delta evolution has been collectively mediated by relative sea-level changes, continental hydrology and human impacts. In this paper, we present a strontium isotope record from the Maryut lagoon (northwestern Nile delta) to quantify the interplay between relative sea-level variations and Nile flow changes during the past 7500 years. 87Sr/86Sr stratigraphy allows five hydrological stages to be defined. (1) The marine transgression of the area is dated to ˜7.5 ka cal. BP, with a clear marine 87Sr/86Sr signature (0.70905-0.7091). (2) Between ˜7 and ˜5.5 ka, in the context of the so-called African Humid Period (AHP), freshwater inputs became progressively predominant in the Maryut's hydrology. Deceleration of sea-level rise coupled with high Nile discharge induced coastal progradation which led to the progressive closure of the Maryut lagoon. (3) Between ˜5.5 and ˜3.8 ka, the end of the AHP is translated by a progressive hydrological shift from a Nile-dominated to a marine-dominated lagoon (87Sr/86Sr shifts from 0.70865 to 0.7088 to 0.70905-0.70915). (4) From ˜2.8 to ˜1.7 ka, 87Sr/86Sr ratios shift towards lower values (0.7084). Although this change is not precisely resolved because of a hiatus in the Maryut's sedimentary record, the 87Sr/86Sr transition from sea-like to Nile-dominated values is attributed to irrigation practices since the early Ptolemaic period (i.e. since ˜2.3 ka), including the Alexandria canal which played a key role in isolating the Maryut from the Mediterranean sea. (5) The final phase of the record covers the period between ˜1.7 and ˜0.2 ka. 87Sr/86Sr ratios indicate high freshwater inputs (from 0.7080 to 0.7085), except between 1.2 and 1.1 to ˜0.7 ka, when a Maryut lowstand and seawater intrusion are attested. In modern times, the Nile's coastal lagoons have been increasingly supplied by freshwater linked to the diversion of waters from the two Nile branches into the irrigation system. It is suggested that this

  17. Wind-induced circulation in a large tropical lagoon: Chetumal Bay

    NASA Astrophysics Data System (ADS)

    Palacios, E.; Carrillo, L.

    2013-05-01

    Chetumal Bay is a large tropical lagoon located at the Mesoamerican Reef System. Windinduced circulation in this basin was investigated by using direct measurements of current, sea level, and 2d barotropic numerical model. Acoustic Doppler Profiler (ADP) transects covering the north of Chetumal Bay during two campaigns September 2006 and March 2007 were used. The 2d barotropic numerical model was ROMs based and wind forced. Wind information was obtained from a meteorological station located at ECOSUR Chetumal. Sea level data was collected from a pressure sensor deployed in the lagoon. A seasonal pattern of circulation was observed. From observations, during September 2006, a northward flow was shown in most part of the bay and a southward flow in the eastern coast was observed with velocities ranged from 6 cm s-1 to 36 cm s-1. In March 2007, the current pattern was more complex; divergences and converges were identified. The dominant circulation was northward in eastern portion, and southward in the central and western zone. The average current speed was 6 cm s-1 with maximum values of 26 -34 cm s-1. During September 2006 predominant wind was easternsoutheastern and during March 2007, northerly wind events were recorded. Sea level amplitude responded quickly to changes in the magnitude and direction of the wind. Results of sea level and circulation from the 2d barotropic numerical model agreed with observations at first approximation.

  18. A proposed integrated bioindex for the macrofouling biocoenosis of hard substrata in the lagoon of Venice

    NASA Astrophysics Data System (ADS)

    Cima, Francesca; Ballarin, Loriano

    2013-09-01

    Bioindices are often employed to evaluate the ecological status of an unstable habitat such as a lagoon. However, no bioindex to date has considered the macrofouling biocoenosis of hard substrata, which is characterised by a higher biodiversity than that of the benthic communities of soft substrata. We analysed the progression of the hard-substratum biocoenosis at two stations located in the southern basin of the lagoon of Venice using data collected monthly from artificial panels that were immersed continually for a period of one year. Our goal was to develop an integrated specific bioindex, according to the objectives of the Water Framework Directive (WFD) in Europe, that is easy to calculate and provides a useful and immediate value for the ecological status on a logarithmic scale from 1 to 10. The bioindex proposed here takes into account species richness, covering area, and the Q-values of important physico-chemical parameters (e.g., pH, salinity, temperature). To validate the bioindex, our sampling campaign was repeated for an additional year at the two previous stations and a third station in the central basin that had different hydrodynamic features and was subject to greater anthropogenic impact. The ecological status of the third station was "poor-to-moderate", in contrast to the "good" status of the two stations in the southern basin. Seasonal changes in the bioindex values provide useful information on environmental changes because they indicate the moment of an ecological crisis as well as its causes and long-term effects.

  19. Parameterization and extrapolation of in situ predictions of soil methane deposition response to climatic factors

    NASA Astrophysics Data System (ADS)

    Aronson, E. L.; Helliker, B. R.; Strode, S. A.; Pawson, S.

    2011-12-01

    Global soil methane consumption was estimated using multiple regression-based parameterizations by vegetation type from a meta-dataset created from 780 published methane flux measurements. The average global estimates for soil consumption by extrapolation, without taking snow cover into account, totaled 54-60 Tg annually. The parameterizations were based on air temperature and precipitation output variables reported in the literature and gathered in the meta-dataset. These variables were matched to similar ones reported in the Goddard Earth Observing System (GEOS) global climate model. The methane uptake response to increasing precipitation and temperature varied between vegetation types. The parameterizations for methane fluxes by vegetation type were included in a 20 year, free-running, tagged-methane run of the GEOS-5 model constrained by real observations of sea surface temperature. Snow cover was assumed to block methane diffusion into the soil and therefore result in zero consumption of methane in snow-covered soils. The parameterization estimates was slightly higher than previous estimates of global methane consumption, at around 37 Tg annually. The resultant global surface methane concentration was then compared to observed methane concentrations from NOAA Global Monitoring Division sites worldwide, with varying agreement. The parameterization for the vegetation type "Needleleaf Trees" predicted methane consumption in a study site located in the NJ Pinelands, which was studied in 2009. The estimate of methane consumption by the vegetation type "Broadleaf Evergreen Trees" was found to have the greatest error, which may indicate that the factors on which the parameterization was based are of minor importance in regulating methane flux within this vegetation type. The results were compared to offline runs of the parameterizations without the snow-cover compensation, which resulted in global rates of almost double the methane consumption. Since there have been

  20. Methane heat transfer investigation

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Future high chamber pressure LOX/hydrocarbon booster engines require copper base alloy main combustion chamber coolant channels similar to the SSME to provide adequate cooling and reusable engine life. Therefore, it is of vital importance to evaluate the heat transfer characteristics and coking thresholds for LNG (94% methane) cooling, with a copper base alloy material adjacent to he fuel coolant. High pressure methane cooling and coking characteristics recently evaluated at Rocketdyne using stainless steel heated tubes at methane bulk temperatures and coolant wall temperatures typical of advanced engine operation except at lower heat fluxes as limited by the tube material. As expected, there was no coking observed. However, coking evaluations need be conducted with a copper base surface exposed to the methane coolant at higher heat fluxes approaching those of future high chamber pressure engines.

  1. Methane heat transfer investigation

    NASA Technical Reports Server (NTRS)

    Cook, R. T.

    1984-01-01

    Future high chamber pressure LOX/hydrocarbon booster engines require copper-base alloy main combustion chamber coolant channels similar to the SSME to provide adequate cooling and resuable engine life. Therefore, it is of vital importance to evaluate the heat transfer characteristics and coking thresholds for LNG (94% methane) cooling, with a copper-base alloy material adjacent to the fuel coolant. High-pressure methane cooling and coking characteristics were recently evaluated using stainless-steel heated tubes at methane bulk temperatures and coolant wall temperatures typical of advanced engine operation except at lower heat fluxes as limited by the tube material. As expected, there was no coking observed. However, coking evaluations need be conducted with a copper-base surface exposed to the methane coolant at higher heat fluxes approaching those of future high chamber pressure engines.

  2. Enzymatic Oxidation of Methane

    SciTech Connect

    Sirajuddin, S; Rosenzweig, AC

    2015-04-14

    Methane monooxygenases (MMOs) are enzymes that catalyze the oxidation of methane to methanol in methanotrophic bacteria. As potential targets for new gas-to-liquid methane bioconversion processes, MMOs have attracted intense attention in recent years. There are two distinct types of MMO, a soluble, cytoplasmic MMO (sMMO) and a membrane-bound, particulate MMO (pMMO). Both oxidize methane at metal centers within a complex, multisubunit scaffold, but the structures, active sites, and chemical mechanisms are completely different. This Current Topic review article focuses on the overall architectures, active site structures, substrate reactivities, proteinprotein interactions, and chemical mechanisms of both MMOs, with an emphasis on fundamental aspects. In addition, recent advances, including new details of interactions between the sMMO components, characterization of sMMO intermediates, and progress toward understanding the pMMO metal centers are highlighted. The work summarized here provides a guide for those interested in exploiting MMOs for biotechnological applications.

  3. Electrochemical methane sensor

    DOEpatents

    Zaromb, S.; Otagawa, T.; Stetter, J.R.

    1984-08-27

    A method and instrument including an electrochemical cell for the detection and measurement of methane in a gas by the oxidation of methane electrochemically at a working electrode in a nonaqueous electrolyte at a voltage about 1.4 volts vs R.H.E. (the reversible hydrogen electrode potential in the same electrolyte), and the measurement of the electrical signal resulting from the electrochemical oxidation.

  4. Laser beam methane detector

    NASA Technical Reports Server (NTRS)

    Hinkley, E. D., Jr.

    1981-01-01

    Instrument uses infrared absorption to determine methane concentration in liquid natural gas vapor. Two sensors measure intensity of 3.39 mm laser beam after it passes through gas; absorption is proportional to concentration of methane. Instrument is used in modeling spread of LNG clouds and as leak detector on LNG carriers and installations. Unit includes wheels for mobility and is both vertically and horizontally operable.

  5. Ocean-lagoon water and plankton exchanges in a semi-closed pearl farming atoll lagoon (Ahe, Tuamotu archipelago, French Polynesia)

    NASA Astrophysics Data System (ADS)

    Pagano, M.; Rodier, M.; Guillaumot, C.; Thomas, Y.; Henry, K.; Andréfouët, S.

    2017-05-01

    In atoll lagoons, plankton richness is highly dependent on water exchange with the ocean through the atoll rim. However, the dynamics of the physical and biological fluxes at the lagoon-ocean interface remain poorly characterized. Here, we studied the combined effects of lagoon-ocean water exchanges and local environmental conditions on the phyto- and zooplankton abundance and community structure across the atoll lagoon rim of Ahe (Tuamotu Archipelago, French Polynesia). Plankton and environmental variables were monitored in May 2013 (i) at several stations inside and outside the lagoon and (ii) during time-series corresponding to ebb-flood tidal cycles in the two types of channels connecting the lagoon to the ocean: at the passage (300 m long and about 11 m deep) and in hoa (i.e reef-flat less than 50 cm depth). Our results highlight tidally-driven selective plankton exchanges between the lagoon and external ocean. Phytoplankton (chlorophyll-a) and zooplankton biomass were respectively 4 times and 7 times higher in the lagoon than at stations outside the atoll lagoon. Copepoda was the dominant zooplankton group at the oceanic station (>75% abundance) whereas meroplankton (with bivalve larvae most common) was dominant at the lagoon stations (54%), in the passage (55-82%) and in hoa (>80%). These differences between sites suggest a loss of bivalve larvae through export to the ocean and retention and/or increased production of copepods in the lagoon. The daily export of bivalve larvae represents a low percentage of the lagoon stock, in agreement with previously published larval dispersal numerical models. The retention of copepods could constitute a significant input of nutrients and organic matter (through excretion, feces release, decomposition, and remineralization) into the lagoon.

  6. Evaluation of short-rotation woody crops to stabilize a decommissioned swine lagoon

    Treesearch

    K.C. Dipesh; Rodney E. Will; Thomas C. Hennessey; Chad J. Penn

    2012-01-01

    Fast growing tree stands represent an environmentally friendly, less expensive method for stabilization of decommissioned animal production lagoons than traditional lagoon closure. We tested the feasibility of using short-rotation woody crops (SRWCs) in central Oklahoma to close a decommissioned swine lagoon by evaluating the growth performance and nutrient uptake of...

  7. A system for estimating bowen ratio And evaporation from waste lagoons

    USDA-ARS?s Scientific Manuscript database

    A low cost system was deployed above a swine waste lagoon to obtain estimates of Bowen ratios and characterize lagoon temperatures. The system consisted of humidity and temperature sensors and anemometers deployed above the lagoon, water temperature sensors, and a meteorological station located by t...

  8. Nutrient-Chlorophyll Relationships in the Indian River Lagoon, Florida(SEERS)

    EPA Science Inventory

    The Indian River Lagoon is a highly diverse estuary located along Florida’s Atlantic coast. The system is made up of the main stem and two side-lagoons: the Banana River and Mosquito Lagoon. We segmented the main stem into three sections based on spatial trends in water quality ...

  9. 75 FR 53960 - Chignik Lagoon Power Utility; Notice of Declaration of Intention and Soliciting Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-02

    ... Energy Regulatory Commission Chignik Lagoon Power Utility; Notice of Declaration of Intention and... Lagoon Power Utility. e. Name of Project: Packers Creek Hydroelectric Project. f. Location: The proposed Packers Creek Hydroelectric Project will be located on Packers Creek, near the community of Chignik Lagoon...

  10. Nutrient-Chlorophyll Relationships in the Indian River Lagoon, Florida(SEERS)

    EPA Science Inventory

    The Indian River Lagoon is a highly diverse estuary located along Florida’s Atlantic coast. The system is made up of the main stem and two side-lagoons: the Banana River and Mosquito Lagoon. We segmented the main stem into three sections based on spatial trends in water quality ...

  11. Evolution and vitality of seagrasses in a Mediterranean lagoon.

    PubMed

    Ferrat, Lila; Fernandez, C; Pasqualini, V; Pergent, G; Pergent-Martini, C

    2003-08-01

    Despite their registration on the list of the Ramsar convention sites, the Mediterranean lagoons rarely beneficiate of an effective protection, and are particularly sensitive to environmental quality. A control of these wetlands needs the creation of an inventory of knowledge for the concerned environment. In this perspective, the seagrass beds were followed up in the coastal lagoon of Urbino (Corse, France) since 1990. A cartographic study was carried out by remote sensing of aerial photography. Temporal evolution of the seagrass beds (Cymodocea nodosa principally) allows to determine the vitality of these structures. A comparison of the surface areas occupied by Cymodocea nodosa, between 1990 and 1999, did not allow seeing any significant evolution. However, some variations appear like biotopes all more fragile and coveted as the Mediterranean coastal fringe is straight and is the privileged site of appear in the localization of the beds, due to the modification of environmental conditions in the lagoon.

  12. LANDSAT imagery of the Venetian Lagoon: A multitemporal analysis

    NASA Technical Reports Server (NTRS)

    Alberotanza, L.; Zandonella, A. (Principal Investigator)

    1980-01-01

    The use of LANDSAT multispectral scanner images from 1975 to 1979 to determine pollution dispersion in the central basin of the lagoon under varying tidal conditions is described. Images taken during the late spring and representing both short and long range tidal dynamics were processed for partial haze removal and removal of residual striping. Selected spectral bands were correlated to different types of turbid water. The multitemporal data was calibrated, classified considering sea truth data, and evaluated. The classification differentiated tide diffusion, algae belts, and industrial, agricultural, and urban turbidity distributions. Pollution concentration is derived during the short time interval between inflow and outflow and from the distance between the two lagoon inlets and the industrial zones. Increasing pollution of the lagoon is indicated.

  13. Gas movement through fractured landfill cover materials

    SciTech Connect

    Bogner, J.E.; Moore, C.A.

    1986-01-01

    Bidirectional gas movement through fractured landfill cover materials is being studied at the Mallard North Landfill in DuPage County, Illinois. Vertical pressure and concentration gradients were monitored during changing meteorological and soil moisture conditions. Nests of probes for direct observation of subsurface soil gas pressures were installed in the top of the refuse and at depths of 1.2 m and 0.6 m. Subsurface gas pressures, barometric pressure, wind speed, wind direction, solar radiation, air temperature, and precipitation were continuously monitored. A field gas chromatograph permitted frequent analysis of methane, carbon dioxide, nitrogen, and oxygen in soil gas samples from the various probes. Tensiometers provided information on soil moisture conditions. During dry weather, soil gas pressures at all depths equilibrated rapidly with barometric pressure and exhibited diurnal variations that were inversely proportional to diurnal temperature variations. When cover materials became saturated, changes in soil gas pressures sometimes lagged behind changes in atmospheric pressure by two to three hours. Soil gas concentrations generally exhibited relatively small short-term variations, but responded over the longer term to changing soil moisture conditions. Carbon-dioxide:methane ratios suggest that an important near-surface process is the activity of methane-oxidizing bacteria, which consume methane that might otherwise be available to a gas recovery system.

  14. State Waste Discharge Permit application, 100-N Sewage Lagoon

    SciTech Connect

    Not Available

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations (Ecology et al. 1994), the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173--216 (or 173--218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. As a result of this decision, the Washington State Department of Ecology and the US Department of Energy, Richland Operations Office entered into Consent Order No. DE 91NM-177, (Ecology and DOE-RL 1991). This document constitutes the State Waste Discharge Permit application for the 100-N Sewage Lagoon. Since the influent to the sewer lagoon is domestic waste water, the State Waste Discharge Permit application for Public Owned Treatment Works Discharges to Land was used. Although the 100-N Sewage Lagoon is not a Public Owned Treatment Works, the Public Owned Treatment Works application is more applicable than the application for industrial waste water. The 100-N Sewage Lagoon serves the 100-N Area and other Hanford Site areas by receiving domestic waste from two sources. A network of sanitary sewer piping and lift stations transfers domestic waste water from the 100-N Area buildings directly to the 100-N Sewage Lagoon. Waste is also received by trucks that transport domestic waste pumped from on site septic tanks and holding tanks. Three ponds comprise the 100-N Sewage Lagoon treatment system. These include a lined aeration pond and stabilization pond, as well as an unlined infiltration pond. Both piped-in and trucked-in domestic waste is discharged directly into the aeration pond.

  15. Eutrophication Process on Coastal Lagoons of North of Sinaloa, Mexico

    NASA Astrophysics Data System (ADS)

    Escobedo-Urias, D.; Martinez-Lopez, A.

    2007-05-01

    Coastal ecosystems in the Gulf of California support diverse and important fisheries and are reservoirs of great biological diversity. In northern Sinaloa, population growth and development, as well as increased use of these natural systems for recreation, has substantially increased the pressure placed upon marine resources. Discharge of untreated wastewaters generated by diverse human activities has been notably altered its health and integrity, principally along the lagoon's eastern shore In the late 60s, agriculture moved into a dominant role in coastal northern Sinaloa. The coastal plain encompasses more than 200,000 hectares under cultivation that now introduces large amounts of organic material, pesticides, heavy metals, and fertilizers into the lagoon systems of Topolobampo and San Ignacio-Navachiste-Macapule System at drainage discharge points and a minor grade in Colorado Lagoon. These lagoons are shallow and exhibit low water quality, lost of lagoon depth, presence of toxic substances (heavy metals) near the discharge points of wastewaters, and presence of harmful algal blooms. With the aim of evaluate the nutrients loadings (wastewaters, groundwaters) and their effects on the coastal lagoons of north of Sinaloa, the preliminary analysis of the physical, chemical and biologic variables data series are analyzed. From 1987-2007 eutrophication process is identified in Topolobampo Complex show increase tendency in annual average concentrations of DIN (Dissolved Inorganic Nitrogen= NO2+NO3) from 0.5 μ M in 1987 to 2.7 μ M in 2006. Trophic Index (TRIX) values, low nutrient ratios (N: P and N: Si) and the phytoplanktonic community structure support this result. Preliminary results of nutrients loadings show a mayor contribution of wastewaters into the coastal zone.

  16. Spreading lagooned sewage sludge on farm land: A case history

    SciTech Connect

    Robson, C.M.; Sommers, L.E.

    1995-06-01

    This report describes the development of a project involving the application of approximately 265,000 cubic meters of lagooned sewage sludge from a metropolitan area on privately-owned farm land in an adjacent, rural county. The sludge application project was initiated to enable use of the land occupied by the lagoons for expansion of the sewage treatment plant. The procedures developed will be valuable to those proposing to practice land disposal of stabilized sludge as part of the Nation`s resource conservation program.

  17. Population studies on the Amphipoda of Mazoma Lagoon (Greece)

    NASA Astrophysics Data System (ADS)

    Karakiri, Maria; Nicolaidou, Artemis

    1987-12-01

    The life cycles of four amphipod species— Gammarus insensibilis, Dexamine spinosa, Microdeutopus gryllotalpa and Corophium insidiosum—were studied in the brackish-water lagoon Mazoma of the Amvrakikos Gulf, Ionian Sea. G. insensibilis has an annual life cycle with limited recruitment over the year and maximum reproductive activity in the winter months. D. spinosa exhibits continuous recruitment in the lagoon with a maximum in summer. Both species produce a single brood per female per yer. Continuous recruitment was observed during the summer months for M. gryllotalpa and C. insidiosum, and multiple breeding per female per year. Sex ratios varied considerably over the year, with a persisting preponderance of the females.

  18. Optical researches for cyanobacteria bloom monitoring in Curonian Lagoon

    NASA Astrophysics Data System (ADS)

    Shirshin, Evgeny A.; Budylin, Gleb B.; Yakimov, Boris P.; Voloshina, Olga V.; Karabashev, Genrik S.; Evdoshenko, Marina A.; Fadeev, Victor V.

    2016-04-01

    Cyanobacteria bloom is a great ecological problem of Curonian Lagoon and Baltic Sea. The development of novel methods for the on-line control of cyanobacteria concentration and, moreover, for prediction of bloom spreading is of interest for monitoring the state of ecosystem. Here, we report the results of the joint application of hyperspectral measurements and remote sensing of Curonian Lagoon in July 2015 aimed at the assessment of cyanobacteria communities. We show that hyperspectral data allow on-line detection and qualitative estimation of cyanobacteria concentration, while the remote sensing data indicate the possibility of cyanobacteria bloom detection using the spectral features of upwelling irradiation.

  19. Methane Emissions from Upland Forests

    NASA Astrophysics Data System (ADS)

    Megonigal, Patrick; Pitz, Scott; Wang, Zhi-Ping

    2016-04-01

    Global budgets ascribe 4-10% of atmospheric methane sinks to upland soils and assume that soils are the sole surface for methane exchange between upland forests and the atmosphere. The dogma that upland forests are uniformly atmospheric methane sinks was challenged a decade ago by the discovery of abiotic methane production from plant tissue. Subsequently a variety of relatively cryptic microbial and non-microbial methane sources have been proposed that have the potential to emit methane in upland forests. Despite the accumulating evidence of potential methane sources, there are few data demonstrating actual emissions of methane from a plant surface in an upland forest. We report direct observations of methane emissions from upland tree stems in two temperate forests. Stem methane emissions were observed from several tree species that dominate a forest located on the mid-Atlantic coast of North America (Maryland, USA). Stem emissions occurred throughout the growing season while soils adjacent to the trees simultaneously consumed methane. Scaling fluxes by stem surface area suggested the forest was a net methane source during a wet period in June, and that stem emissions offset 5% of the soil methane sink on an annual basis. High frequency measurements revealed diurnal cycles in stem methane emission rates, pointing to soils as the methane source and transpiration as the most likely pathway for gas transport. Similar observations were made in an upland forest in Beijing, China. However, in this case the evidence suggested the methane was not produced in soils, but in the heartwood by microbial or non-microbial processes. These data challenge the concept that forests are uniform sinks of methane, and suggest that upland forests are smaller methane sinks than previously estimated due to stem emissions. Tree emissions may be particularly important in upland tropical forests characterized by high rainfall and transpiration.

  20. Formation and retention of methane in coal

    SciTech Connect

    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.

  1. X-ray Fluorescence Measurements of Turbulent Methane-Oxygen Shear Coaxial Flames (Briefing Charts)

    DTIC Science & Technology

    2015-03-01

    Briefing Charts 3. DATES COVERED (From - To) March 2015-May 2015 4. TITLE AND SUBTITLE X-ray Fluorescence Measurements of Turbulent Methane -Oxygen Shear...1 DISTRIBUTION A: Approved for public release; distribution unlimited. Clearance # X-ray Fluorescence Measurements of Turbulent Methane -Oxygen Shear

  2. Sediment budget in the Lagoon of Venice, Italy

    NASA Astrophysics Data System (ADS)

    Sarretta, A.; Pillon, S.; Molinaroli, E.; Guerzoni, S.; Fontolan, G.

    2010-05-01

    A comparison of 1927, 1970 and 2002 bathymetric surveys in the Lagoon of Venice was used to reconstruct historical changes in sedimentation. A detailed GIS-based analysis of the charts revealed the timing and pattern of geomorphic changes and allowed calculation of sediment deposition and erosion for the entire lagoon and each of its four sub-basins: Treporti, Lido, Malamocco and Chioggia. Two main developments are discernible from comparative observation of the areal distribution of the main elevation ranges: the diminution in area of the saltmarshes, which decreased by more than 50%, from 68 km 2 in 1927 to 32 km 2 in 2002, and the progressive deepening of the lagoon, with a huge increase in the area of subtidal flats (between -0.75 and -2.00 m depth), from 88 to 206 km 2 during the same period. Generally, the lagoon showed a clear-cut change in the most frequent depths (modal depth) from a value of -0.62 m in 1927 to -0.88 m in 2002. The deepening of the lagoon affected mostly the lagoonal sub-basins south of the town of Venice, where modal depth increased from -0.65 to -1.12 m in Lido, from -0.64 to -1.75 m in Malamocco and from -0.39 to -0.88 m in Chioggia. Large changes in lagoonal morphology were caused by human-induced subsidence, the dredging of navigation channels between 1927 and 1970, and intense natural erosion enhanced by sediment re-suspension due to Manila clam fishing between 1970 and 2002. There was a net loss of about 110 Mm 3 of sediment from the lagoon, most of which (73 Mm 3, ca.70%) was in the earlier period. A significant amount was lost by dredging and direct disposal outside the system, either on land or at sea, and there was a net loss of 39 Mm 3 from the lagoon to the sea through the inlets, at an annual rate of 0.5 Mm 3. Comparison of erosion rates in the two periods revealed an alarming acceleration, from a net sediment loss of 0.3 Mm 3 yr -1 in the period 1927-1970 to 0.8 Mm 3 yr -1 in 1970-2002. Deterioration caused a shift from a

  3. HYDROBIOLOGICAL CHARACTERISTICS OF THE COASTAL LAGOONS AT HUGH TAYLOR BIRCH STATE RECREATION AREA, FORT LAUDERDALE, FLORIDA: A HISTORICAL PERSPECTIVE.

    USGS Publications Warehouse

    Brock, Robert J.

    1987-01-01

    The author presents initial results of an ongoing study of Southeast Florida coastal lagoon lakes. Objectives include presenting environmental conditions within and adjacent to the lagoons under a variety of hydrologic conditions and to determine water-quality changes in ground water and surface water and how these changes in water quality affect lagoonal biological communities within the lagoons.

  4. Isotopic Tracers of Methane in Wetlands and Landfill Studies

    NASA Astrophysics Data System (ADS)

    Chanton, J.; Abichou, T.; Hater, G.

    2006-12-01

    Isotopic characterization is useful for determining variation in methane production mechanism and oxidation. In landfills, the quantity of methane oxidized is one of the largest uncertainties. The extent of methane oxidation can be constrained by measurements of methane within the production zone and captured escaping from the surface of the cover soil. The shift in d13C and dD of methane in these two pools is proportional to the degree of methane oxidation. This approach can be employed in wetlands and rice fields, but it is complicated by the greater complexities of gas transport processes which fractionation methane according to its isotopic composition. For determination of production mechanism, use of d13C is uncontroversial. However, there is disagreement between the results of field studies and laboratory incubation studies concerning the interpretation of dD of CH4. A compilation of field studies will be presented to help resolve this matter. Finally, the natural abundance of radiocarbon can be used to determine the sources of organic matter which fuel microbial respiration. Evidence of differences between wetland types will be presented.

  5. Lagoon Seepage Testing Procedures for Central Facilities Area (CFA) Sewage Lagoons at Idaho National Laboratory Butte County, Idaho April 2014

    SciTech Connect

    Alan Giesbrecht

    2014-05-01

    The lagoon seepage testing procedures are documented herein as required by the Wastewater Rules (IDAPA 58.01.16.493). The Wastewater Rules and Wastewater Reuse Permit LA-000141-03 require that the procedure used for performing a seepage test be approved by IDEQ prior to conducting the seepage test. The procedures described herein are based on a seepage testing plan that was developed by J-U-B ENGINEERS, Inc. (J-U-B) and has been accepted by several IDEQ offices for lagoons in Idaho.

  6. Stable carbon isotopic signature of methane from high-emitting wetland sites in discontinuous permafrost landscape

    NASA Astrophysics Data System (ADS)

    Marushchak, Maija; Liimatainen, Maarit; Lind, Saara; Biasi, Christina; Martikainen, Pertti

    2017-04-01

    The rising methane concentration in the atmosphere during the past years has been associated with a concurrent change in the carbon isotopic signature: The atmospheric methane is getting more and more depleted in the heavy carbon isotope. The decreasing 13C/12C ratio indicates an increasing contribution of methane from biogenic sources, most importantly wetlands and inland waters, whose global emissions are still poorly constrained. From the climate change perspective, arctic and subarctic wetlands are particularly interesting due to the strong warming and permafrost thaw predicted for these regions that will cause changes in the methane dynamics. Coupling methane flux inventories with determination of the stable isotopic signature can provide useful information about the pathways of methane production, consumption and transport in these ecosystems. Here, we present data on the emissions and carbon isotopic composition of methane from subarctic tundra wetlands at the Seida study site, Northeast European Russia. In this landscape, underlain by discontinuous permafrost, waterlogged fens represent sites of high carbon turnover and high methane release. Despite they cover less than 15% of the region, their methane emissions comprise 98% of the regional mean (± SD) release of 6.7 (± 1.8) g CH4 m-2 y-1 (Marushchak et al. 2016). The methane emission from the studied fens was clearly depleted in 13C compared to the pore water methane. The bulk mean δ13CH4 (± SD) over the growing season was -68.2 (± 2.0) ‰ which is similar to the relatively few values previously reported from tundra wetlands. We explain the depleted methane emissions by the high importance of passive transport via aerenchymous plants, a process that discriminates against the heavier isotopes. This idea is supported by the strong positive correlation observed between the methane emission and the vascular leaf area index (LAI), and the inverse relationship between the δ13CH4 of emitted methane and LAI

  7. Radon Indicates Hydrological Connection between the Ocean and Lagoon, Santa Cruz, CA

    NASA Astrophysics Data System (ADS)

    Vattadi, N.; Foley, N.; Lecher, A.; Murray, J.

    2013-12-01

    Lagoons are common along the coastline of Santa Cruz, CA. In the summer dry season, Corcoran Lagoon in Santa Cruz, California is separated from the ocean by a 100 meter long sand berm. Because sand is a porous medium, water can flow through the berm with a maximum calculated speed of 0.427 meters per hour at Corcoran Lagoon. Previous studies have shown that radon can be used as an indicator of submarine groundwater discharge into the ocean and that discharge into the ocean fluctuates as a function of tide. We used similar techniques in the lagoon to measure 222Rn as groundwater stored in the berm is pushed into the lagoon by the advancing tide. We also measured the salinity of water stored in the berm water at three temporary wells and compared it to seawater and lagoon water at the same time as our radon measurements. As the tide advanced, we observed a radon and salinity increase near the midpoint of the lagoon. The highest salinity measurements, which were higher than both the ocean and the lagoon, were recorded in the berm at the temporary well nearest to the lagoon. These data indicate that the berm stores high salinity and radon rich groundwater which is then pushed into the lagoon with a rising tide which demonstrates the hydrological connection between the lagoon and the ocean.

  8. Combustion of Methane Hydrate

    NASA Astrophysics Data System (ADS)

    Roshandell, Melika

    A significant methane storehouse is in the form of methane hydrates on the sea floor and in the arctic permafrost. Methane hydrates are ice-like structures composed of water cages housing a guest methane molecule. This caged methane represents a resource of energy and a potential source of strong greenhouse gas. Most research related to methane hydrates has been focused on their formation and dissociation because they can form solid plugs that complicate transport of oil and gas in pipelines. This dissertation explores the direct burning of these methane hydrates where heat from the combustion process dissociates the hydrate into water and methane, and the released methane fuels the methane/air diffusion flame heat source. In contrast to the pipeline applications, very little research has been done on the combustion and burning characteristics of methane hydrates. This is the first dissertation on this subject. In this study, energy release and combustion characteristics of methane hydrates were investigated both theoretically and experimentally. The experimental study involved collaboration with another research group, particularly in the creation of methane hydrate samples. The experiments were difficult because hydrates form at high pressure within a narrow temperature range. The process can be slow and the resulting hydrate can have somewhat variable properties (e.g., extent of clathration, shape, compactness). The experimental study examined broad characteristics of hydrate combustion, including flame appearance, burning time, conditions leading to flame extinguishment, the amount of hydrate water melted versus evaporated, and flame temperature. These properties were observed for samples of different physical size. Hydrate formation is a very slow process with pure water and methane. The addition of small amounts of surfactant increased substantially the hydrate formation rate. The effects of surfactant on burning characteristics were also studied. One finding

  9. Methane formation and methane oxidation by methanogenic bacteria.

    PubMed Central

    Zehnder, A J; Brock, T D

    1979-01-01

    Methanogenic bacteria were found to form and oxidize methane at the same time. As compared to the quantity of methane formed, the amount of methane simultaneously oxidized varied between 0.3 and 0.001%, depending on the strain used. All the nine tested strains of methane producers (Methanobacterium ruminantium, Methanobacterium strain M.o.H., M. formicicum, M. thermoautotrophicum, M. arbophilicum, Methanobacterium strain AZ, Methanosarcina barkeri, Methanospirillum hungatii, and the "acetate organism") reoxidized methane to carbon dioxide. In addition, they assimilated a small part of the methane supplied into cell material. Methanol and acetate also occurred as oxidation products in M. barkeri cultures. Acetate was also formed by the "acetate organism," a methane bacterium unable to use methanogenic substrates other than acetate. Methane was the precursor of the methyl group of the acetate synthesized in the course of methane oxidation. Methane formation and its oxidation were inhibited equally by 2-bromoethanesulfonic acid. Short-term labeling experiments with M. thermoautotrophicum and M. hungatii clearly suggest that the pathway of methane oxidation is not identical with a simple back reaction of the methane formation process. Images PMID:762019

  10. Possible Methane Sources and Sinks

    NASA Image and Video Library

    2014-12-16

    This illustration portrays possible ways methane might be added to Mars atmosphere sources and removed from the atmosphere sinks. NASA Curiosity Mars rover has detected fluctuations in methane concentration in the atmosphere.

  11. Leaking methane reservoirs offshore Svalbard

    NASA Astrophysics Data System (ADS)

    Minshull, T. A.; Westbrook, G. K.; Weitemeyer, K. A.; Sinha, M. C.; Goswami, B. K.; Marsset, B.

    2012-10-01

    Methane hydrate—a solid substance in which methane is trapped within ice-like crystals—is stable at low temperatures and high pressures and may be destabilized by ocean warming on both geological and human time scales. Methane is a powerful greenhouse gas, and methane released from hydrate provides a potential positive feedback mechanism in global climate change [e.g., Archer and Buffett, 2005]—in theory, the more methane is released by the hydrates, the warmer the climate gets, causing the ocean to warm and release more methane. However, methane escaping from the seabed is oxidized and dissolved in the ocean, and insufficient methane may reach the atmosphere to affect the climate significantly. Its importance for climate change therefore depends on whether the flux from the seabed is great enough to overcome solution in the ocean and perturb atmospheric concentrations over sufficiently long time scales.

  12. Antibiotic Resistant Bacterial Profiles of Anaerobic Swine Lagoon Effluent

    USDA-ARS?s Scientific Manuscript database

    Although land application of swine manure lagoon effluent is a common and effective method of disposal, the presence of antibiotic-resistant bacteria, both pathogenic and commensal can complicate already understood issues associated with its safe disposal. The aim of this study was to assess antibi...

  13. Antibiotic resistant bacterial profiles of anaerobic swine lagoon effluent

    USDA-ARS?s Scientific Manuscript database

    Although land application of swine manure lagoon effluent is a common and effective method of disposal, the presence of antibiotic-resistant bacteria, both pathogenic and commensal can complicate already understood issues associated with its safe disposal. To better understand this, more data is ne...

  14. A new sampler for stratified lagoon chemical and microbiological assessments

    USDA-ARS?s Scientific Manuscript database

    A water column sampler was needed to study stratification of nutrients and bacteria in a swine manure lagoon. Conventional samplers yielded shallow samples near the bank or required a boat. These limitations prompted development of a new sampler to collect at multiple depths with minimal disturbanc...

  15. Holocene carbonate sedimentation in Aitutaki Lagoon, Cook Islands, South Pacific

    SciTech Connect

    Richmond, B.M.; Hein, J.R.

    1987-05-01

    Aitutaki, an almost-atoll in the Southern Cook Islands, is characterized by a shallow enclosed lagoon. Sediment distribution within the lagoon can be broadly placed into three sedimentary-bathymetric provinces. (1) A low-relief reef rim (< 2 m deep), including sand flats and washover fans, is comprised mostly of clean sand and gravel. (2) The majority of the lagoon floor, which lies between 3 and 6 m water depth, is dominated by sand and silt; coral-algal patch reefs are common with densities greater than 500 reefs/km/sup 2/. Sediment commonly is coarser grained near the patch reefs. (3) Enclosed and elongate-sinuous topographic lows (basins) up to 10 m deep are marked by coral-algal reef growth along their margins. These features are typically narrow, less than 100 m wide, and are U-shaped in cross section and infilled by carbonate and terrigenous muds. High-resolution continuous seismic profiling and limited drilling indicate that differences in thickness of Holocene sediment result from primary irregularities in the pre-Holocene basement surface. Aitutaki was formed by late Miocene volcanism, with a post-edifice building mid-Pleistocene (0.77 Ma) volcanic episode. Two islets within the lagoon are also of volcanic origin, and sinuous coral ridges which extend for several kilometers probably developed on Quaternary lava flows. The coral ridges and meandering enclosed basins appear to be unique to Aitutaki in the Cook Islands.

  16. Augmenting Lagoon Process Using Reactivated Freeze-dried Biogranules.

    PubMed

    Pishgar, Roya; Hamza, Rania Ahmed; Tay, Joo Hwa

    2017-02-24

    This study investigated the feasibility of using freeze-dried biogranules in lagoon basins. The effect of different operational conditions on treatment performance and detention time of granule-based lagoons was examined in a series of laboratory-scale batch studies. Optimal granule dosage was 0.1 g/L under anaerobic condition, resulting in 80-94% removal of 1000 mg/L chemical oxygen demand (COD) in 7-10 days. Under aerobic condition, granule dosage of 0.2 g/L achieved the best result for identical COD concentration. However, adequate amount of nutrients (optimal COD/N/P ratio of 100/13/0.8) should be supplied to encourage the growth of aerobic species. At optimal COD/N/P ratio, aerobic treatment interval significantly reduced to 2-3 days with corresponding COD removal efficiency of 88-92%. Inhibition of high concentrations of COD (5000 mg/L) and ammonia (480 mg/L NH4-N) was observed on microbial activity and treatment capacity of the biogranules. Mixing was a crucial measure to overcome mass transfer limitation. Onetime inoculation of lagoon with fresh granules was the best approach to achieve a satisfactory treatment efficiency. This study suggested that utilization of the biogranules is a feasible and sustainable technique for augmenting lagoon plants in terms of improved effluent quality and reduced retention time. Graphical Abstract ᅟ.

  17. LAGOON WATER FROM CONFINED ANIMAL FEED OPERATIONS AND AMPHIBIAN DEVELOPMENT

    EPA Science Inventory


    Lagoon Water from Confined Animal Feed Operations and Amphibian Development. Dumont, J. N.* and Slagle, S., Oklahoma State University, Stillwater, OK, and Hutchins, S. R., U.S. Environmental Protection Agency (NRMRL/SPRD), Ada, OK. There is some evidence that confined anima...

  18. Aerated Lagoons. Instructor's Guide. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This unit (which consists of a single lesson) describes the structural and operationally unique features of aerated lagoons. In addition, special troubleshooting and maintenance problems are discussed. The instructor's guide for the unit includes: (1) an overview of the lesson; (2) lesson plan; (3) lecture outline (keyed to a set of slides used…

  19. Antibiotic resistant bacterial profiles of anaerobic swine lagoon effluent.

    PubMed

    Brooks, J P; McLaughlin, M R

    2009-01-01

    Although land application of swine (Sus scrofa) manure lagoon effluent is a common and effective method of disposal, the presence of antibiotic-resistant bacteria, both pathogenic and commensal can complicate already understood issues associated with its safe disposal. The aim of this study was to assess antibiotic resistance in swine lagoon bacteria from sow, nursery, and finisher farms in the southeastern United States. Effluents from 37 lagoons were assayed for the presence of Escherichia coli, Campylobacter, Listeria, and Salmonella. Antibiotic resistance profiles were determined by the Kirby-Bauer swab method for 12 antibiotics comprising eight classes. Statistical analyses indicated that farm type influenced the amount and type of resistance, with nurseries and sow farms ranking as most influential, perhaps due to use of more antibiotic treatments. Finisher farms tended to have the least amount of antibiotic class resistance, signaling an overall healthier market pig, and less therapeutic or prophylactic antibiotic use. Many bacterial isolates were resistant to penicillin, cephalosporin, and tetracycline class antibiotics, while nearly all were susceptible to quinolone antibiotics. It appeared that swine farm type had a significant association with the amount of resistance associated with bacterial genera sampled from the lagoons; nurseries contributed the largest amount of bacterial resistance.

  20. Fate of estradiol and testosterone in anaerobic lagoon digestors

    USDA-ARS?s Scientific Manuscript database

    Laboratory-scale lagoon digestors were constructed, and the fate of 14C-labelled 17ß-estradiol (E2) and testosterone (Test) were monitored for 42 d anaerobically under biological and sterile conditions. Hormone levels decreased in the liquid layer and increased in the sludge with time. At 42 d, 16-2...

  1. Facultative Lagoons. Instructor's Guide. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This instructor's guide contains materials needed to teach a two-lesson unit on the structure and components of facultative lagoons, the biological theory of their operation, and factors affecting their operation. Control testing recommendations, maintenance guidelines, and troubleshooting hints are also provided. These materials include: (1) an…

  2. In situ microbial treatment of landfill leachate using aerated lagoons.

    PubMed

    Mehmood, M K; Adetutu, E; Nedwell, D B; Ball, A S

    2009-05-01

    The aim of this study was to assess the efficiency of leachate treatment by microbial oxidation in four connected on-site aerated lagoons at a landfill site. The landfill site was found to be in an ageing methanogenic state, producing leachate with relatively low COD (mean value 1740 mg l(-1)) and relatively high ammonium concentrations (mean value 1241 mg l(-1)). Removal of COD averaged 75%, with retention times varying from 11 to 254 days. Overall 80% of the N load was removed within the plant, some by volatilisation of ammonium. Microbial community profiling of the water from each lagoon showed a divergent community profile, presumably a reflection of the nutrient status in each lagoon. In municipal solid waste landfills under similar conditions, leachate treatment through a facultative aerobic system in which sequential aerobic and anaerobic microbial oxidations occurred can readily be achieved using a simple two-lagoon system, suggesting this technology can be economic to install and simple to run.

  3. Estimating greenhouse gas emissions from a waste lagoon

    USDA-ARS?s Scientific Manuscript database

    A cost-effective approach was used to investigate the relationship between emission of the greenhouse gases (GHG) CO2, CH4, and N2O and energy fluxes from a swine waste lagoon. Energy fluxes were calculated using the Penman method. The energy fluxes showed a diurnal pattern as expected of such flux...

  4. A Field Study Training Program on Wastewater Lagoon Systems.

    ERIC Educational Resources Information Center

    Water and Wastewater Technical School, Neosho, MO.

    This publication is a text and reference manual for operating personnel of both large and small wastewater lagoon systems with support from the Environmental Protection Agency (EPA). As a text, this inservice training manual is intended to be used in a correspondence course wherein the trainee or operator would read and study each chapter before…

  5. Tidal and residual circulations in coupled restricted and leaky lagoons

    NASA Astrophysics Data System (ADS)

    Guyondet, Thomas; Koutitonsky, Vladimir G.

    2008-04-01

    Finite element numerical modelling based on field data is used to study the tidal and tidally induced residual circulation dynamics of a coupled "restricted" and "leaky" coastal lagoon system located in the Magdalen Islands, Gulf of Saint-Lawrence. Havre-aux-Maisons Lagoon (HML) is of a "restricted" nature with a neutral inlet in terms of tidal asymmetry. Grande-Entrée Lagoon (GEL) is of a "leaky" nature with a marked ebb dominance at the inlet due to direct interactions between the main astronomical tidal constituents. The imbalance caused by the different tidal filtering characteristics of both inlets combines with the internal morphological asymmetries of the system to produce a residual throughflow from HML to GEL. The residual circulation is also characterized by strongest values at both inlets, very weak residual currents in HML deep basin and a dipole of residual eddies over the deeper areas of GEL. Further investigations including numerical tracer experiments will be necessary to achieve a full understanding of the long term circulation of this lagoonal system.

  6. A Field Study Training Program on Wastewater Lagoon Systems.

    ERIC Educational Resources Information Center

    Water and Wastewater Technical School, Neosho, MO.

    This publication is a text and reference manual for operating personnel of both large and small wastewater lagoon systems with support from the Environmental Protection Agency (EPA). As a text, this inservice training manual is intended to be used in a correspondence course wherein the trainee or operator would read and study each chapter before…

  7. The high resolution mapping of the Venice Lagoon tidal network

    NASA Astrophysics Data System (ADS)

    Madricardo, Fantina; Foglini, Federica; Kruss, Aleksandra; Bellafiore, Debora; Trincardi, Fabio

    2017-04-01

    One of the biggest challenges of the direct observation of the ocean is to achieve a high resolution mapping of its seafloor morphology and benthic habitats. So far, sonars have mapped just 0.05% of the ocean floor with less than ten-meter resolution. The recent efforts of the scientific community have been devoted towards the mapping of both Deep Ocean and very shallow coastal areas. Coastal and transitional environments in particular undergo strong morphological changes due to natural and anthropogenic pressure. Nowadays, only about 5% of the seafloor of these environments † have been mapped: the shallowness of these environments has prevented the use of underwater acoustics to reveal their morphological features. The recent technological development of multibeam echosounder systems, however, enables these instruments to achieve very high performances also in such shallow environments. In this work, we present results and case studies of an extensive multibeam survey carried out in the Lagoon of Venice in 2013. The Lagoon of Venice is the biggest lagoon in the Mediterranean Sea with a surface of about 550 km2 and with an average depth of about 1 m. In the last century, the morphological and ecological properties of the lagoon changed dramatically: the surface of the salt marshes was reduced by 60% and some parts of the lagoon are deepening with a net sediment flux exiting from the inlets. Moreover, major engineering interventions are currently ongoing at the inlets (MOSE project). These changes at the inlets could affect substantially the lagoon environment. To understand and monitor the future evolution of the Lagoon of Venice, ISMAR within the project RITMARE (a National Research Programme funded by the Italian Ministry of University and Research) carried out an extensive survey, involving a team of more than 25 scientists, to collect high resolution (0.5 m) bathymetry of key study areas such as the tidal inlets and channels. Following a broad

  8. Transformations in methane hydrates

    USGS Publications Warehouse

    Chou, I.-Ming; Sharma, A.; Burruss, R.C.; Shu, J.; Mao, Ho-kwang; Hemley, R.J.; Goncharov, A.F.; Stern, L.A.; Kirby, S.H.

    2000-01-01

    Detailed study of pure methane hydrate in a diamond cell with in situ optical, Raman, and x-ray microprobe techniques reveals two previously unknown structures, structure II and structure H, at high pressures. The structure II methane hydrate at 250 MPa has a cubic unit cell of a = 17.158(2) A?? and volume V = 5051.3(13) A??3; structure H at 600 MPa has a hexagonal unit cell of a = 11.980(2) A??, c = 9.992(3) A??, and V = 1241.9(5) A??3. The compositions of these two investigated phases are still not known. With the effects of pressure and the presence of other gases in the structure, the structure II phase is likely to dominate over the known structure I methane hydrate within deep hydrate-bearing sediments underlying continental margins.

  9. Catalytic aromatization of methane.

    PubMed

    Spivey, James J; Hutchings, Graham

    2014-02-07

    Recent developments in natural gas production technology have led to lower prices for methane and renewed interest in converting methane to higher value products. Processes such as those based on syngas from methane reforming are being investigated. Another option is methane aromatization, which produces benzene and hydrogen: 6CH4(g) → C6H6(g) + 9H2(g) ΔG°(r) = +433 kJ mol(-1) ΔH°(r) = +531 kJ mol(-1). Thermodynamic calculations for this reaction show that benzene formation is insignificant below ∼600 °C, and that the formation of solid carbon [C(s)] is thermodynamically favored at temperatures above ∼300 °C. Benzene formation is insignificant at all temperatures up to 1000 °C when C(s) is included in the calculation of equilibrium composition. Interestingly, the thermodynamic limitation on benzene formation can be minimized by the addition of alkanes/alkenes to the methane feed. By far the most widely studied catalysts for this reaction are Mo/HZSM-5 and Mo/MCM-22. Benzene selectivities are generally between 60 and 80% at methane conversions of ∼10%, corresponding to net benzene yields of less than 10%. Major byproducts include lower molecular weight hydrocarbons and higher molecular weight substituted aromatics. However, carbon formation is inevitable, but the experimental findings show this can be kinetically limited by the use of H2 or oxidants in the feed, including CO2 or steam. A number of reactor configurations involving regeneration of the carbon-containing catalyst have been developed with the goal of minimizing the cost of regeneration of the catalyst once deactivated by carbon deposition. In this tutorial review we discuss the thermodynamics of this process, the catalysts used and the potential reactor configurations that can be applied.

  10. Water sources, mixing and evaporation in the Akyatan lagoon, Turkey

    NASA Astrophysics Data System (ADS)

    Lécuyer, C.; Bodergat, A.-M.; Martineau, F.; Fourel, F.; Gürbüz, K.; Nazik, A.

    2012-12-01

    Akyatan lagoon, located southeast of Turkey along the Mediterranean coast, is a choked and hypersaline lagoon, and hosts a large and specific biodiversity including endangered sea turtles and migrating birds. Physicochemical properties of this lagoon were investigated by measuring temperature, salinity, and hydrogen and oxygen isotope ratios of its waters at a seasonal scale during years 2006 and 2007. Winter and spring seasons were dominated by mixing processes between freshwaters and Mediterranean seawater. The majority of spring season waters are formed by evapoconcentration of brackish water at moderate temperatures of 22 ± 2 °C. During summer, hypersaline waters result from evaporation of seawater and brackish waters formed during spring. Evaporation over the Akyatan lagoon reaches up to 76 wt% based on salinity measurements and operated with a dry (relative humidity of 0.15-0.20) and hot (44 ± 6 °C) air. These residual waters were characterized by the maximal seasonal isotopic enrichment in both deuterium and 18O relative to VSMOW. During autumn, most lagoonal waters became hypersaline and were formed by evaporation of waters that had isotopic compositions and salinities close to that of seawater. These autumnal hypersaline waters result from an air humidity close to 0.45 and an atmospheric temperature of evaporation of 35 ± 5 °C, which are responsible for up to 71 wt% of evaporation, with restricted isotopic enrichments relative to VSMOW. During the warm seasons, the combination of air humidity, wind velocity and temperature were responsible for a large kinetic component in the total isotopic fractionation between water liquid and water vapour.

  11. Nitrification and denitrification gene abundances in swine wastewater anaerobic lagoons.

    PubMed

    Ducey, Thomas F; Shriner, Anthony D; Hunt, Patrick G

    2011-01-01

    Although anaerobic lagoons are used globally for livestock waste treatment, their detailed microbial cycling ofN is only beginning to become understood. Within this cycling, nitrification can be performed by organisms that produce the enzyme ammonia monooxygenase. For denitrification, the reduction of nitrite to nitric oxide can be catalyzed by two forms of nitrite reductases, and N,O can be reduced by nitrous oxide reductase encoded by the gene nosZ The objectives of this investigation were to (i) quantify the abundance of the amoA, nirK, nirS, and nosZ genes; (ii) evaluate the influence of environmental conditions on their abundances; and (iii) evaluate their abundance relative to denitrification enzyme activity (DEA). Samples were analyzed via real-time quantitative polymerase chain reaction and collected from eight typical, commercial anaerobic, swine wastewater lagoons located in the Carolinas. The four genes assayed in this study were present in all eight lagoons. Their abundances relative to total bacterial populations were 0.04% (amoA), 1.33% (nirS), 5.29% (nirK), and 0.27% (nosZ). When compared with lagoon chemical characteristics, amoA and nirK correlated with several measured variables. Neither nirS nor nosZ correlated with any measured environmental variables. Although no gene measured in this study correlated with actual or potential DEA, nosZ copy numbers did correlate with the disparity between actual and potential DEA. Phylogenetic analysis ofnosZdid not reveal any correlations to DEA rates. As with other investigations, analyses of these genes provide useful insight while revealing the underlying greater complexity of N cycling within swine waste lagoons.

  12. Phytoremediation of Atmospheric Methane

    DTIC Science & Technology

    2013-04-15

    bacterial genes for the three subunit proteins of the soluble methane monooxygenase and with two associated genes, the mmoG and the mmoC. The...plant, Arabidopsis thaliana, with the bacterial genes for the three subunit proteins of the soluble methane monooxygenase and with two associated genes...transcription and activity, perhaps as a chaperone.  Here we report that we have transformed a plant, Arabidopsis thaliana, with the  bacterial  genes for the

  13. Methane-Powered Airplane

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Beech Aircraft's Corporation's Boulder Division developed expertise in producing superinsulated virtually leak-proof cryogenic equipment for storing liquid oxygen and hydrogen fuels in NASA's Apollo, Skylab and Space Shuttle programs. Boulder Division used this experience in designing a fuel storage tank for liquid methane, a "cryogenic" fuel that must be supercooled to keep it liquid. Beech Aircraft is producing a four-place lightplane powered by liquid methane (LM) which is stored in two of these specially designed cryogenic storage tanks holding 18 gallons each.

  14. Impact of a river flash flood on microbial carbon and nitrogen production in a Mediterranean Lagoon (Thau Lagoon, France)

    NASA Astrophysics Data System (ADS)

    Fouilland, E.; Trottet, A.; Bancon-Montigny, C.; Bouvy, M.; Le Floc'h, E.; Gonzalez, J.-L.; Hatey, E.; Mas, S.; Mostajir, B.; Nouguier, J.; Pecqueur, D.; Rochelle-Newall, E.; Rodier, C.; Roques, C.; Salles, C.; Tournoud, M.-G.; Vidussi, F.

    2012-11-01

    Over half of the total nitrogen, phosphorus, silicate and dissolved organic carbon (DOC) loading was discharged from the Vène River into the Thau Lagoon waters within the first five days of what was considered to be the autumn flash flood period. Such loads represented about 8% and 3% of the yearly averaged total nitrogen and phosphorus load in Thau Lagoon, respectively. Although this event affected >20% of the total lagoon volume, river trace metal loads contributed apparently only weakly to the increase in labile trace metal concentrations in the lagoon surface waters. Differences between theoretical dilution values and observed values were also noticed for phosphate, silicate and dissolved organic carbon (DOC) concentrations. DOC losses (10-50%) mainly through flocculation, together with the substantial increases in some metallic contaminants such as Zn (from 6 to >30 μg L-1) observed during the flash flood in saline lagoon waters, may have limited the carbon production of bacterial communities. The potential osmotic shock and the increase in turbidity may mainly explain the low phytoplankton C turnover rates (average of 0.02 h-1) measured in brackish waters (<30) during periods of heavy flood discharge. The dissolved inorganic nitrogen (DIN: NO3 + NH4) enrichment measured 12 days after the flash flood event in saline lagoon surface waters (from 22 to 143 μg N L-1) led to a substantial increase in phytoplanktonic C production and associated DIN uptake rates (from 2.6 to 7.0 μg C L-1 h-1 and from 0.5 to 1.1 μg N L-1 h-1, respectively). Subsequent accumulation in particulate organic carbon and nitrogen was not observed in the area studied during and after the flash flood period, averaging 549 ± 50 μg C L-1 and 168 ± 9 μg N L-1, respectively. This suggests that most of locally produced microbial production was rapidly filtered by oysters contributing to about 13% of the yearly exploited production in the lagoon and/or exported through sedimentation.

  15. Simulations of Methane Hydrate Phenomena Over Geologic Timescales. Part I: Effect of Sediment Compaction Rates on Methans Hydrate and Free Gas Accumulation

    SciTech Connect

    Gering, Kevin Leslie

    2003-01-01

    The focus of this work is a model that describes migration and biogenic formation of methane under conditions representative of dynamic marine basins, and the conversion of soluble methane into either solid hydrate or exsolved gas. Incorporated into the overall model are an accurate phase equilibria model for seawater-methane, a methane source term based on biogenesis data, and a sediment compaction model based on porosity as a function of position, time, and the local volume fractions of hydrate solids and free gas. Simulations have shown that under some compaction scenarios, liquid overpressures reach the lithostatic limit due to permeability constraints, which can diminish the advective transfer of soluble methane within the porous sediment. As such, the formation of methane hydrate can be somewhat of a self-moderating process. The occurrence and magnitude of hydrate formation is directly tied to fundamental parameters such as the compaction/sedimentation rates, liquid advection rates, seafloor depth, geothermal gradient, etc. Results are shown for simulations covering 20 million years, wherein growth profiles for methane hydrate and free gas (neither exceeding 10 vol% at any location) are tracked within a vertical sediment column spanning over 3000 m. A case study is also presented for the Blake Ridge region (Ocean Drilling Program Leg 164, Sites 994, 995, and 997) based on simulations covering 6 Ma, wherein it is concluded that methane migration from compaction-driven advection may account for 15-30% of the total hydrate mass present in this region.

  16. The Airborne Measurements of Methane Fluxes (AIRMETH) Arctic Campaign (Invited)

    NASA Astrophysics Data System (ADS)

    Serafimovich, A.; Metzger, S.; Hartmann, J.; Kohnert, K.; Sachs, T.

    2013-12-01

    One of the most pressing questions with regard to climate feedback processes in a warming Arctic is the regional-scale methane release from Arctic permafrost areas. The Airborne Measurements of Methane Fluxes (AIRMETH) campaign is designed to quantitatively and spatially explicitly address this question. Ground-based eddy covariance (EC) measurements provide continuous in-situ observations of the surface-atmosphere exchange of methane. However, these observations are rare in the Arctic permafrost zone and site selection is bound by logistical constraints among others. Consequently, these observations cover only small areas that are not necessarily representative of the region of interest. Airborne measurements can overcome this limitation by covering distances of hundreds of kilometers over time periods of a few hours. Here, we present the potential of environmental response functions (ERFs) for quantitatively linking methane flux observations in the atmospheric surface layer to meteorological and biophysical drivers in the flux footprints. For this purpose thousands of kilometers of AIRMETH data across the Alaskan North Slope are utilized, with the aim to extrapolate the airborne EC methane flux observations to the entire North Slope. The data were collected aboard the research aircraft POLAR 5, using its turbulence nose boom and fast response methane and meteorological sensors. After thorough data pre-processing, Reynolds averaging is used to derive spatially integrated fluxes. To increase spatial resolution and to derive ERFs, we then use wavelet transforms of the original high-frequency data. This enables much improved spatial discretization of the flux observations, and the quantification of continuous and biophysically relevant land cover properties in the flux footprint of each observation. A machine learning technique is then employed to extract and quantify the functional relationships between the methane flux observations and the meteorological and

  17. Methane mass balance at three landfill sites: What is the efficiency of capture by gas collection systems?

    SciTech Connect

    Spokas, K. . E-mail: spokas@morris.ars.usda.gov; Bogner, J.; Chanton, J.P.; Morcet, M.; Aran, C.; Graff, C.; Golvan, Y. Moreau-Le; Hebe, I.

    2006-07-01

    Many developed countries have targeted landfill methane recovery among greenhouse gas mitigation strategies, since methane is the second most important greenhouse gas after carbon dioxide. Major questions remain with respect to actual methane production rates in field settings and the relative mass of methane that is recovered, emitted, oxidized by methanotrophic bacteria, laterally migrated, or temporarily stored within the landfill volume. This paper presents the results of extensive field campaigns at three landfill sites to elucidate the total methane balance and provide field measurements to quantify these pathways. We assessed the overall methane mass balance in field cells with a variety of designs, cover materials, and gas management strategies. Sites included different cell configurations, including temporary clay cover, final clay cover, geosynthetic clay liners, and geomembrane composite covers, and cells with and without gas collection systems. Methane emission rates ranged from -2.2 to >10,000 mg CH{sub 4} m{sup -2} d{sup -1}. Total methane oxidation rates ranged from 4% to 50% of the methane flux through the cover at sites with positive emissions. Oxidation of atmospheric methane was occurring in vegetated soils above a geomembrane. The results of these studies were used as the basis for guidelines by the French environment agency (ADEME) for default values for percent recovery: 35% for an operating cell with an active landfill gas (LFG) recovery system, 65% for a temporary covered cell with an active LFG recovery system, 85% for a cell with clay final cover and active LFG recovery, and 90% for a cell with a geomembrane final cover and active LFG recovery.

  18. Methane emissions from natural wetlands

    SciTech Connect

    Meyer, J.L.; Burke, R.A. Jr.

    1993-09-01

    Analyses of air trapped in polar ice cores in conjunction with recent atmospheric measurements, indicate that the atmospheric methane concentration increased by about 250% during the past two or three hundred years (Rasmussen and Khalil, 1984). Because methane is a potent ``greenhouse`` gas, the increasing concentrations are expected to contribute to global warning (Dickinson and Cicerone, 1986). The timing of the methane increase suggests that it is related to the rapid growth of the human population and associated industrialization and agricultural development. The specific causes of the atmospheric methane concentration increase are not well known, but may relate to either increases in methane sources, decreases in the strengths of the sinks, or both.

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

    USGS Publications Warehouse

    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.

  20. Methane Clathrate Hydrate Prospecting

    NASA Technical Reports Server (NTRS)

    Duxbury, N.; Romanovsky, V.

    2003-01-01

    A method of prospecting for methane has been devised. The impetus for this method lies in the abundance of CH4 and the growing shortages of other fuels. The method is intended especially to enable identification of subpermafrost locations where significant amounts of methane are trapped in the form of methane gas hydrate (CH4(raised dot)6H2O). It has been estimated by the U.S. Geological Survey that the total CH4 resource in CH4(raised dot) 6H2O exceeds the energy content of all other fossil fuels (oil, coal, and natural gas from non-hydrate sources). Also, CH4(raised dot)6H2O is among the cleanest-burning fuels, and CH4 is the most efficient fuel because the carbon in CH4 is in its most reduced state. The method involves looking for a proxy for methane gas hydrate, by means of the combination of a thermal-analysis submethod and a field submethod that does not involve drilling. The absence of drilling makes this method easier and less expensive, in comparison with prior methods of prospecting for oil and natural gas. The proposed method would include thermoprospecting in combination with one more of the other non-drilling measurement techniques, which could include magneto-telluric sounding and/or a subsurface-electrical-resistivity technique. The method would exploit the fact that the electrical conductivity in the underlying thawed region is greater than that in the overlying permafrost.

  1. Saturn Methane Image

    NASA Image and Video Library

    2004-03-05

    NASA's Cassini narrow angle camera took this image of Saturn on Feb. 16, 2004, from a distance of 66.1 million kilometers (41.1 million miles) in a special filter which reveals clouds and haze high in the atmosphere. The image scale is 397 kilometers (247 miles) per pixel. The MT2 spectral filter samples a near-infrared region of the electromagnetic spectrum where methane gas absorbs light at a wavelength of 727 nanometers. In the image, methane gas is uniformly mixed with hydrogen, the main gas in Saturn's atmosphere. Dark locales are places of strong methane absorption, relatively free of high clouds; the bright areas are places with high, thick clouds which shield the methane below. Image details reveal a high, thick equatorial cloud and a relatively deep or thin haze encircling the pole, as well as several distinct latitude bands with different cloud height attributes. It also shows a high atmospheric disturbance, just south of the equator, which has persisted throughout the 1990s in images returned by NASA's Hubble Space Telescope. Four of Saturn's moons are visible (clockwise from above right): Enceladus (499 kilometers, or 310 miles across); Mimas (396 kilometers, or 245 miles across); Tethys (1,060 kilometers, or 659 miles across); and Rhea (1,528 kilometers, or 949 miles across). The imaging team enhanced the brightness of Mimas and Enceladus by a factor of three. http://photojournal.jpl.nasa.gov/catalog/PIA05381

  2. An integrated Pan-European perspective on coastal Lagoons management through a mosaic-DPSIR approach.

    PubMed

    Dolbeth, Marina; Stålnacke, Per; Alves, Fátima L; Sousa, Lisa P; Gooch, Geoffrey D; Khokhlov, Valeriy; Tuchkovenko, Yurii; Lloret, Javier; Bielecka, Małgorzata; Różyński, Grzegorz; Soares, João A; Baggett, Susan; Margonski, Piotr; Chubarenko, Boris V; Lillebø, Ana I

    2016-01-18

    A decision support framework for the management of lagoon ecosystems was tested using four European Lagoons: Ria de Aveiro (Portugal), Mar Menor (Spain), Tyligulskyi Liman (Ukraine) and Vistula Lagoon (Poland/Russia). Our aim was to formulate integrated management recommendations for European lagoons. To achieve this we followed a DPSIR (Drivers-Pressures-State Change-Impacts-Responses) approach, with focus on integrating aspects of human wellbeing, welfare and ecosystem sustainability. The most important drivers in each lagoon were identified, based on information gathered from the lagoons' stakeholders, complemented by scientific knowledge on each lagoon as seen from a land-sea perspective. The DPSIR cycles for each driver were combined into a mosaic-DPSIR conceptual model to examine the interdependency between the multiple and interacting uses of the lagoon. This framework emphasizes the common links, but also the specificities of responses to drivers and the ecosystem services provided. The information collected was used to formulate recommendations for the sustainable management of lagoons within a Pan-European context. Several common management recommendations were proposed, but specificities were also identified. The study synthesizes the present conditions for the management of lagoons, thus analysing and examining the activities that might be developed in different scenarios, scenarios which facilitate ecosystem protection without compromising future generations.

  3. Crustacean zooplankton in aerated wastewater treatment lagoons as a potential feedstock for biofuel.

    PubMed

    Kring, Stefanie A; Xia, Xiaoyan; Powers, Susan E; Twiss, Michael R

    2013-01-01

    Zooplankton biomass productivity was estimated for two 64,000 m3 (1.7 ha) facultative aerated wastewater treatment lagoons to evaluate potential biodiesel production from zooplankton biomass. Lagoons were monitored bi-weekly during summer 2010. Lipid accumulated by crustacean zooplankton was considered the most efficient means by which to collect lipid produced by phytoplankton owing to the greater ease in the collection of these organisms (>0.153mm) compared with unicellular algae (size <0.06 mm). In terms of biomass, the cladoceran Daphnia and the copepod Cyclops were the dominant zooplankton in these hypereutrophic lagoons, while unicellular chlorophytes dominated the phytoplankton community. Secondary productivity of these lagoons (250 g of dry weight m(-2) yr(-1)) is comparable to the secondary productivity of other sewage lagoons. The potential biodiesel production for one lagoon was estimated to be 0.04 +/- 0.02 L m(-2) yr(-1), which results in a total of 1120 +/- 560 L from two lagoons. This study showed that there are organisms present in wastewater lagoons, besides algae, that can serve as a biofuel feedstock. Additionally, this research expands the current knowledge of facultative aerated wastewater lagoon ecology and waste stream-derived biofuel. Future research should include complete life cycle and economic analyses to determine if harvesting zooplankton from wastewater lagoons is a sustainable endeavour.

  4. Biogeochemical responses of shallow coastal lagoons to Climate Change

    NASA Astrophysics Data System (ADS)

    Brito, A.; Newton, A.; Tett, P.; Fernandes, T.

    2009-04-01

    The importance of climate change and global warming in the near future is becoming consensual within the scientific community (e.g. Kerr et al., 2008; Lloret et al., 2008). The surface temperature and sea level have increased during the last few years in the northern hemisphere (IPCC, 2007). Predictions for future changes include an increase of surface temperature and sea level for Europe. Moreover, the global warming phenomenon will also change the hydrological cycle and increase precipitation in northern and central Europe (IPCC, 2007). Sea level rise already threatens to overwhelm some lagoons, such as Venice and Moroccan lagoons (Snoussi et al., 2008). Shallow coastal lagoons are some of the most vulnerable systems that will be impacted by these changes (Eisenreich, 2005). Environmental impacts on coastal lagoons include an increase of water turbidity and therefore light attenuation. If these effects are strong enough, the lighted bottoms of shallow lagoons may loose a significant part of the benthic algal community. These communities are highly productive and are essential to control nutrient dynamics of the system by uptaking large amounts of nutrients both from the water column and from the sediments. A decrease in benthic algal communities and photosynthetic oxygen production will also contribute to increasing the vulnerability of the lagoons to hypoxia and anoxia. The flux of nutrients such as phosphate from the sediments may increase dramatically, further disrupting the nutrient balance and condition and promoting cyanobacterial blooms. Microbial activity is temperature dependent, therefore, the increase of temperature will increase the concentrations of ammonium within sediments. The release of phosphate and silicate will also increase with temperature. Coastal lagoons are valuable ecosystems and may be severely impacted, both ecologically and economically, by global change. Shallow coastal lagoons should be considered as sentinel systems and should be

  5. Methane bubbling: from speculation to quantification

    NASA Astrophysics Data System (ADS)

    Grinham, A. R.; Dunbabin, M.; Yuan, Z.

    2013-12-01

    Rates of methane bubbling (ebullition) represent a notoriously difficult emission pathway to quantify with highly variable spatial and temporal changes. However, the importance of bubbling fluxes in terms of total emissions is increasingly recognised from a number of different globally relevant natural systems including lakes, reservoirs and wetlands. This represents a critical challenge to current survey efforts to quantify greenhouse gas emissions and reduce the uncertainty associated with bubbling fluxes. A number of different methods have been proposed to overcome this challenge including bubble traps, floating chambers, echo sounders, laser spectrography and camera systems. Each method has relative merits and deficiencies with all trading-off the ability to directly quantify methane and provide spatial and temporal coverage. Here we present a novel method that allows direct measurement of methane bubble concentration as well as the ability to persistently monitor a wide spatial area. Central to the monitoring system is an Autonomous Surface Vessel (ASV) and an Optical Methane Detector (OMD). The ASV is equipped with solar panels and uses electric motors for propulsion to allow persistent environmental monitoring. The OMD has a path length of 1.3 m and 7 Hz sampling so a typical mission of 3 hours at 1 m s-1 covers an area in excess of 10 000 m2 and over 65 000 data points. The system was assessed on four sub-tropical freshwater reservoirs of varying surface area (0.5 to 100 km2), age (2 to 65 y) and catchment land use (40 to 90% natural vegetation cover). Each reservoir had unique challenges in terms of navigation and field conditions to test feasibility of this method. Deployment length varied from a single day to over 4 months to test method durability. In addition to ASV bubble surveys, floating static chambers were deployed to determine diffusive fluxes. Localised instantaneous bubble flux rates within a single reservoir ranged over three orders of

  6. Toxicity of contaminants in lagoons and pannes of the Indiana Dunes National Lakeshore

    SciTech Connect

    Gillespie, R.; Speelman, J.; Stewart, P.M.

    1995-12-31

    Contaminants in water and sediments of lagoons and pannes were 2--90 times greater at sites adjacent to slag and coal piles than those at reference sites. One site (Lagoon-US5) had sediments with very high concentrations of toxic organics (e.g. naphthalene, phenanthrene, dibenzofuran). Although analyses indicated a gradient of contaminant concentration with distance from their sources, toxicity assays were somewhat equivocal. With the exception of less reproduction in Ceriodaphnia at one lagoon site (US3 = 0.55 of reference), survival of fathead minnows and reproduction in Ceriodaphnia in lagoon and panne waters varied independently of the contaminant concentration. In fact, there was better Ceriodaphnia reproduction in water from two contaminated sites (Lagoon-US5, Panne-WP1) than in water from reference sites. Fathead minnow survival, Ceriodaphnia survival, Ceriodaphnia reproduction, amphipod survival, and amphipod growth varied among sites in toxicity assays with sediments, 100% mortality of fatheads at Lagoon-US5, 100% mortality of Ceriodaphnia at Lagoon-US3, and less survival of fathead minnows at Lagoon-US3 indicate possible toxicity from contaminants in sediments at these sites. Of all organisms and end-points tested, Ceriodaphnia survival seemed to be most closely associated with concentrations of contaminants in lagoon water and sediments. Amphipod survival also varied with contaminants in sediments, however, survival in sediments of contaminated sites ranged only from 0.90--0.93 of reference sites. Although the results are not consistent among organisms, toxicity assays indicate that sediments from the lagoon site with the highest contaminants (Lagoon-US5) and possibly those from another contaminated lagoon site (Lagoon-US3) could be toxic to aquatic organisms. Water and sediments from contaminated panne sites do not appear to be toxic to aquatic test organisms.

  7. Methane production, emission and possible control measures in the rice agriculture

    NASA Astrophysics Data System (ADS)

    Wang, Mingxing; Shangguan, Xingjian; Shen, Renxing; Reiner, Wassmann; Wolfgang, Seiler

    1993-09-01

    In the rice field methane is produced in the soil layer with depths of 2 25 cm. The vertical profile of methane production rate in the paddy soil during the water covering period differs from that in the paddy soil in dry phase. Only a small part, about 30%, of the produced methane is emitted to the atmosphere through rice plant, air bubbles, and molecular diffusion. Therefore, the methane emission rate from the rice field depends not only on the methane production rate in the soil, but also on the transport efficiency of the rice plant, air bubble formation that in turn depends on the production rate, and molecular diffusion. Field measurements show that methane emission rates from a particular rice field have very large diurnal, seasonal and interannual variations, which are related to soil characteristics, water regime, farming procedure, local climate, and rice growing activities. The relationship between the methane emission rate and the above mentioned factors is very complicated. The emission rates from different rice fields differ greatly not only in the absolute value, but also in the temporal variation patterns. Methane emission rate from the rice field may be significantly reduced by scientific management of fertilizer and irrigation. While the use of SO{4/2-} containing fertilizer and fermented organic fertilizer may reduce the methane emission significantly, the most promising measure for reducing methane emission from rice field is the frequent drainage irrigation procedure.

  8. The landfill methane balance: Model and practical applications

    SciTech Connect

    Bogner, J.; Spokas, K.

    1995-10-01

    A rational mass-balance framework is described for improved quantification of landfill methane processes at a given site. The methane balance model examines the partitioning of methane generated into methane recovered (via extraction systems), methane emitted, methane oxidized, methane migrated, and methane storage. This model encourages use of field-based data to better quantify rates of methane recovery and emissions.

  9. A Geochemical Model for the Origin of Methane on Titan

    NASA Astrophysics Data System (ADS)

    Glein, C. R.; Shock, E. L.

    2007-12-01

    The existence of methane in Titan's atmosphere has been a mystery for years [1]. The short photochemical lifetime of methane in the atmosphere suggests that methane is replenished from the interior. Observations by Cassini-Huygens have offered new insights into the origin of methane on Titan. These data have confirmed that Titan's methane is endogenic [2], consistent with geophysical models [3]. Today, an issue is the origin of methane on Titan in general. Why does Titan have methane in the first place? Here, we show that methane formation would have been unavoidable on early Titan. It is likely that Titan accreted materials similar to carbonaceous chondrites and comets, except for extreme volatiles in comets, such as carbon monoxide. Thus, we assume that Titan started with Fe-Ni metals and sulfides, silicates and oxides of the rock-forming elements, organic matter, carbon dioxide, methanol, and ammonia. After accretion, radiogenic heat would have melted ice, facilitating water-rock separation and interaction. Mineral dissolution and precipitation, along with acid-base reactions, would have been facile throughout differentiation, despite the low temperature. In contrast, most redox reactions, notably organic matter decomposition, would have been slow in cold aqueous solution. Eventually, the interior would have segregated into a muddy core, covered by a high-pressure ice layer, overlain by a salty ocean, capped by an ice shell [3]. The primordial muddy core would have been composed of phyllosilicates, organic matter, carbonates, sulfides, and presumably, metals. The early salty ocean would have been rich in sodium chloride and bicarbonate, in addition to methanol and ammonium salts. Methane would not have formed in hydrothermal systems at the ocean floor because the high-pressure ice layer would have inhibited hydrothermal circulation. Instead, we propose that methane is a byproduct of the thermal evolution of the core. Specifically, our core devolatilization

  10. Methane Emissions from Deciduous Trees

    NASA Astrophysics Data System (ADS)

    Rice, A. L.; Teama, D.; Khalil, M. K.; Shearer, M. J.; Rosenstiel, T. N.

    2008-12-01

    There is some disagreement today over whether terrestrial plants present a significant source of methane to the atmosphere. Even if the plants are recognized as a source, there is no clear method to extrapolate plant emissions to the global atmospheric budget of methane and estimates vary widely. There is also no consensus on a mechanism for methane production and/or plant-mediated transport to the atmosphere. Here, we present preliminary data showing a significant flux of methane to the atmosphere from three wetland deciduous tree species. Ash (Fraxinus latifolia), cottonwood (Populus deltoides L.), and willow (Salix fluviatillis) were grown in a greenhouse under inundated rice-cultivation conditions using a rice straw amendment equivalent to 3 t/ha to enhance below ground anaerobic methane production. Results of measurements of redox potential and methane concentrations in soil pore water show significant methane production similar to that observed in rice plots (Oryza sative L. 'M-103') and controls of the same treatment. Measurements of the stable carbon isotopic composition (δ13C) of methane dissolved in soil pore water show no significant difference from rice plots showing no discernable difference in bulk carbon substrate. Methane flux from trees, measured using static flux chamber and bag-tree enclosures, was found to be significantly higher than control treatments (i.e., no plants) but lower than rice plants overall. The carbon isotopic composition of emitted methane from tree species was found to be approximately 8‰ enriched in δ13C compared with methane emitted from rice. This difference in δ13C of emitted methane observed between rice and trees suggests the mechanisms contributing to regulating plant-mediated methane transport (e.g. transport, oxidation, carbon sources) may be quite distinct between diverse plant functional types. Identifying the mechanistic basis of this response will be a key development towards developing more accurate estimates

  11. Patterns and Controls of Erosion along the Elson Lagoon Coastline, Barrow, Alaska (2003-2016)

    NASA Astrophysics Data System (ADS)

    Tweedie, C. E.; Escarzaga, S. M.; Cody, R. P.; Manley, W. F.; Gaylord, A. G.; Aiken, Q.; Lopez, A. F.; Aguirre, A.; George, C.; Nelson, L.; Brown, J.

    2016-12-01

    With arctic warming and the combined effect of decreased summer sea ice extent, longer fetch for wave propagation, warmer sea surface and ground temperature, and longer periods of open water; the propensity for increased arctic coastal erosion rates and land-ocean sediment inputs to increase has been recognized for some time. In this study, we report on coastal erosion trends along a 11km stretch of coastline adjacent to the Barrow Environmental Observatory (BEO) where the position of the 2-4 meter high coastal bluff has been monitored annually with survey grade differential GPS (dGPS). Modern and historic erosion trends can be viewed through interactive web mapping applications at http://barrowmapped.org/. Rates of aerial and volumetric erosion losses averaged 0.7-2.8 meters and 0.8-3.5 cubic meters per meter of coast per year from 2003-2015 for each of the four coastal sections monitored. These losses equate to losses to the atmosphere and/or inputs to lagoon waters 53-220kgC per meter of coast per year. Such aerial losses are lower than from other areas of the Beaufort Sea coast that lack protective barrier islands, but 25-30% higher than historic decadal-scale change rates estimated for this section of coastline. However, regression analyses indicate no significant change to the rate of erosion during the past 13 years. Historic hotspots of erosion remained modern hotspots of erosion, and increases in modern erosion rates were greatest for sections of coast where historically high rates of erosion have been recorded. Regionally, the Elson Lagoon study area shows some of the highest rates of erosion for the Barrow Peninsula, which are generally 2-3 times mean annual erosion rates recorded for the Chukchi Sea Coastline near Barrow. Regression tree analysis used to isolate the relative importance of different biophysical controls of erosion differ between analyses run for aerial and volumetric losses along the Elson Lagoon Coast. These analyses also highlight key

  12. Methane emissions from northern Amazon savanna wetlands and Balbina Reservoir

    NASA Astrophysics Data System (ADS)

    Kemenes, A.; Belger, L.; Forsberg, B.; Melack, J. M.

    2006-12-01

    To improve estimates of methane emission for the Amazon basin requires information from aquatic environments not represented in the central basin near the Solimoes River, where most of the current data were obtained. We have combined intensive, year-long measurements of methane emission and water levels made in interfluvial wetlands located in the upper Negro basin with calculations of inundation based on a time series of Radarsat synthetic aperature radar images. These grass-dominated savannas emitted methane at an average rate of 18 mg C per m squared per day, a low rate compared to the habitats with floating grasses the occur in the Solimoes floodplains. Reservoirs constructed in the Amazon typically flood forested landscapes and lead to conditions conducive for methane production. The methane is released to the atmosphere from the reservoir and as the water exits the turbines and from the downstream river. Balbina Reservoir near Manaus covers about 2400 km squared along the Uatuma River. Annual averages of measurements of methane emission from the various habitats in the reservoir range from 23 to 64 mg C per m squared per day. Total annual emission from the reservoir is about 58 Gg C. In addition, about 39 Gg C per year are released below the dam, about 50 percent of which is released as the water passes through the turbines. On an annual areal basis, Balbina Reservoir emits 40 Mg C km squared, in contrast to 30 Mg km squared for the Solimoes mainstem floodplain

  13. Photosynthetic pigments of Zoster a noltii and Ruppia cirrhosa in some Albanian lagoons

    NASA Astrophysics Data System (ADS)

    Ylli, Arjana; Babani, Fatbardha; Stamo, Iliriana

    2010-01-01

    In the coastal lagoons of Adriatic Sea Zostera noltii and Ruppia cirrhosa are plants with seeds and flowers, that colonizes the sandy bottom of lagoons. They are capable to produce oxygen with very weak light. Characterization of photosynthetic pigments of eelgrass Zostera noltii and Ruppia cirrhosa, were performed during the period 2002-2008 in some Adriatic lagoons: Kune-Vaini, Patog, Karavasta and Narta. Dynamics of chlorophylls and carotenoids during the vegetation period of these plants were characterized. As a result, the chlorophyll content of Zoostera noltii taken from the Kune- Vain lagoon is higher than at plants collected from the other lagoons. The photosynthetic pigment content of the Zostera noltii plants is higher than of Ruppia cirrhosa. The differences on the distribution of these species in the analyzed lagoons are represented in this presentation.

  14. Interannual and cyclone-driven variability in phytoplankton communities of a tropical coastal lagoon.

    PubMed

    Srichandan, Suchismita; Kim, Ji Yoon; Kumar, Abhishek; Mishra, Deepak R; Bhadury, Punyasloke; Muduli, Pradipta R; Pattnaik, Ajit K; Rastogi, Gurdeep

    2015-12-15

    One of the main challenges in phytoplankton ecology is to understand their variability at different spatiotemporal scales. We investigated the interannual and cyclone-derived variability in phytoplankton communities of Chilika, the largest tropical coastal lagoon in Asia and the underlying mechanisms in relation to environmental forcing. Between July 2012 and June 2013, Cyanophyta were most prolific in freshwater northern region of the lagoon. A category-5 very severe cyclonic storm (VSCS) Phailin struck the lagoon on 12th October 2013 and introduced additional variability into the hydrology and phytoplankton communities. Freshwater Cyanophyta further expanded their territory and occupied the northern as well as central region of the lagoon. Satellite remote sensing imagery revealed that the phytoplankton biomass did not change much due to high turbidity prevailing in the lagoon after Phailin. Modeling analysis of species-salinity relationship identified specific responses of phytoplankton taxa to the different salinity regime of lagoon. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Testing Foraminiferal Taphonomy as a Paleo-Tsunami Indicator in an Arid System Lagoon: Sur Lagoon, Sultanate of Oman

    NASA Astrophysics Data System (ADS)

    Pilarczyk, J. E.; Reinhardt, E. G.

    2009-05-01

    On 28 November 1945 a M8.1 subduction zone earthquake which occurred approximately 300 km west of Karachi, Pakistan resulted in a 2-13 m tsunami which reportedly killed 4000 people. Limited historical records show that the Makran Subduction Zone (MSZ) located off the coast of Pakistan has been seismically active and has produced tsunamigenic earthquakes in the past which have impacted the coasts of Iran, Pakistan, India and Oman. However, little is known about the longterm seismicity or tsunami generating capacity of the MSZ, and models for future events are largely based on the limited historical information as no geologic (i.e. tsunami deposit) evidence has been available. Bivalve taphonomy was used in the intertidal Sur Lagoon, Oman to discriminate the 1945 tsunami deposit in trench sections. However, to find older tsunami deposits in the lagoon requires the use of vibracore studies where shell taphonomy is less applicable due the small sample sizes. Here we test the utility of foraminifera (provenance and taphonomy) for detecting and interpreting paleo-tsunami events using the 1945 tsunami shell bed as a guide. The tsunami unit in the eight cores is characterized by a dominant marine assemblage including allochthonous Amphistegina lessonii, Amphistegina lobifera, Ammonia inflata and planktics. The taphonomic characters of this assemblage include low fragmentation, high corrosion, and abundant sediment-filled fossil foraminifera with increased average specimen size. The lack of fragmentation is likely due to the high energy conditions outside the lagoon that breakdown the fragile specimens favouring the larger more robust foraminifera species (i.e. Amphistegina sp.). In contrast, the Lagoonal facies is characterized by Ammonia tepida, Elphidium gerthi and Elphidium advenum with high fragmentation, low abundance of fossil foraminifera, and decreased average specimen size. The high abundance of fragmented specimens is likely due to transport from outside of the

  16. Pilot-scale field study for ammonia removal from lagoon biogas using an acid wet scrubber.

    PubMed

    Lin, Hongjian; Wu, Xiao; Miller, Curtis; Zhu, Jun; Hadlocon, Lara Jane; Manuzon, Roderick; Zhao, Lingying

    2014-01-01

    The anaerobic activities in swine slurry storage and treatment generate biogas containing gaseous ammonia component which is a chemical agent that can cause adverse environmental impacts when released to the atmosphere. The aim of this pilot plant study was to remove ammonia from biogas generated in a covered lagoon, using a sulfuric acid wet scrubber. The data showed that, on average, the biogas contained 43.7 ppm of ammonia and its concentration was found to be exponentially related to the air temperature inside the lagoon. When the air temperature rose to 35°C and the biogas ammonia concentration reached 90 ppm, the mass transfer of ammonia/ammonium from the deeper liquid body to the interface between the air and liquid became a limiting factor. The biogas velocity was critical in affecting ammonia removal efficiency of the wet scrubber. A biogas flow velocity of 8 to 12 mm s(-1) was recommended to achieve a removal efficiency of greater than 60%. Stepwise regression revealed that the biogas velocity and air temperature, not the inlet ammonia concentration in biogas, affected the ammonia removal efficiency. Overall, when 73 g L(-1) (or 0.75 M) sulfuric acid solution was used as the scrubber solution, removal efficiencies varied from 0% to 100% with an average of 55% over a 40-d measurement period. Mass balance calculation based on ammonium-nitrogen concentration in final scrubber liquid showed that about 21.3 g of ammonia was collected from a total volume of 1169 m(3) of biogas, while the scrubber solution should still maintain its ammonia absorbing ability until its concentration reaches up to 1 M. These results showed promising use of sulfuric acid wet scrubber for ammonia removal in the digester biogas.

  17. Priority pesticides in sediments of European coastal lagoons: A review.

    PubMed

    Pinto, M I; Burrows, Hugh D; Sontag, G; Vale, C; Noronha, J P

    2016-11-15

    This review summarizes the legislation applied to pesticides and highlights the physicochemical properties of the past and recently listed PPs under Water Framework Directive (WFD). It reports important information regarding the analysis, occurrence and long-term screening of PPs in sediments of European coastal lagoons. Among the entire list of PPs, those analyzed have been the organochloride insecticides, such as lindane, hexachlorobenzene and DDT. Although flood events pointed to the possible redistribution of pesticides, which may increase under climate change conditions, few studies are available concerning PPs screening in sediments of European coastal lagoons. Data is scarce not only in terms of the number of listed PPs that have been analyzed but also in terms of their long-term screening. This lack of data on PP concentrations is probably a consequence of the fact that less importance is given to the sediments contamination/quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Flooding and Environmental Challenges for Venice and its Lagoon

    NASA Astrophysics Data System (ADS)

    Fletcher, C. A.; Spencer, T.

    2005-07-01

    Time may be running out for Venice. The frequency of flooding is increasing and Venice is no better protected today than it was in November 1966, when a violent storm surge left the city under 2 metres of floodwater. The environmental future is bleak, with continuing land subsidence, acceleration in the rate of sea level rise and possible changes in storminess in prospect. Surrounding the city is a lagoon ecosystem showing signs of severe environmental degradation. This timely scientific and technical volume synthesises the great volume and diversity of recent interdisciplinary research on Venice and its lagoon. The lessons reported here are relevant not only to Venice but also to all those that live and work under the threat of coastal flooding, including the inhabitants of other great cultural centres, like London and St. Petersburg.

  19. Structural dynamics of bacterioplankton assemblages in the Lagoon of Venice

    NASA Astrophysics Data System (ADS)

    Celussi, Mauro; Pugnetti, Alessandra; Del Negro, Paola

    2009-08-01

    In this study we examined the spatial and temporal dynamics of planktonic bacterial assemblages at four different sites in the Lagoon of Venice. Samples were collected in January, April, July and October 2005 and several parameters (temperature, salinity, dissolved oxygen, chlorophyll a, dissolved macronutrients, dissolved and particulate organic carbon, viral and heterotrophic nanoplanktonic abundances) were determined in order to highlight the most important factors which are implied in shaping such assemblages. Furthermore we tested the relationship between similar assemblages and the patterns of activities (prokaryotic carbon production and several hydrolytic activities) that they perform in order to establish if, in this highly variable environment, similar assemblages behave in analogous ways. Results indicate that seasonality act as the main forcing on the communities. Moreover, we found a mismatch between community structure and patterns of activity possibly as a consequence of the heterogeneity of the lagoon which can affect in turn the assemblages' metabolic requirements (and thus their responses).

  20. Seasonal and inter-annual variation in ecosystem scale methane emission from a boreal fen

    NASA Astrophysics Data System (ADS)

    Rinne, Janne; Li, Xuefei; Raivonen, Maarit; Peltola, Olli; Sallantaus, Tapani; Haapanala, Sami; Smolander, Sampo; Alekseychik, Pavel; Aurela, Mika; Korrensalo, Aino; Mammarella, Ivan; Tuittila, Eeva-Stiina; Vesala, Timo

    2016-04-01

    Northern wetlands are one of the major sources of atmospheric methane. We have measured ecosystem scale methane emissions from a boreal fen continuously since 2005. The site is an oligotrophic fen in boreal vegetation zone situated in Siikaneva wetland complex in Southern Finland. The mean annual temperature in the area is 3.3°C and total annual precipitation 710 mm. We have conducted the methane emission measurements by the eddy covariance method. Additionally we have measured fluxes of carbon dioxide, water vapor, and sensible heat together with a suite of other environmental parameters. We have analyzed this data alongside with a model run with University of Helsinki methane model. The measured fluxes show generally highest methane emission in late summers coinciding with the highest temperatures in saturated peat zone. During winters the fluxes show small but detectable emission despite the snow and ice cover on the fen. More than 90% of the annual methane emission occurs in snow-free period. The methane emission and peat temperature are connected in exponential manner in seasonal scales, but methane emission does not show the expected behavior with water table. The lack of water table position dependence also contrasts with the spatial variation across microtopography. There is no systematic variation in sub-diurnal time scale. The general seasonal cycle in methane emission is captured well with the methane model. We will show how well the model reproduces the temperature and water table position dependencies observed. The annual methane emission is typically around 10 gC m-2. This is a significant part of the total carbon exchange between the fen and the atmosphere and about twice the estimated carbon loss by leaching from the fen area. The inter-annual variability in the methane emission is modest. The June-September methane emissions from different years, comprising most of the annual emission, correlates positively with peat temperature, but not with

  1. Transport and reaction processes affecting the attenuation of landfill gas in cover soils.

    PubMed

    Molins, S; Mayer, K U; Scheutz, C; Kjeldsen, P

    2008-01-01

    Methane and trace organic gases produced in landfill waste are partly oxidized in the top 40 cm of landfill cover soils under aerobic conditions. The balance between the oxidation of landfill gases and the ingress of atmospheric oxygen into the soil cover determines the attenuation of emissions of methane, chlorofluorocarbons, and hydrochlorofluorocarbons to the atmosphere. This study was conducted to investigate the effect of oxidation reactions on the overall gas transport regime and to evaluate the contributions of various gas transport processes on methane attenuation in landfill cover soils. For this purpose, a reactive transport model that includes advection and the Dusty Gas Model for simulation of multicomponent gas diffusion was used. The simulations are constrained by data from a series of counter-gradient laboratory experiments. Diffusion typically accounts for over 99% of methane emission to the atmosphere. Oxygen supply into the soil column is driven exclusively by diffusion, whereas advection outward offsets part of the diffusive contribution. In the reaction zone, methane consumption reduces the pressure gradient, further decreasing the significance of advection near the top of the column. Simulations suggest that production of water or accumulation of exopolymeric substances due to microbially mediated methane oxidation can significantly reduce diffusive fluxes. Assuming a constant rate of methane production within a landfill, reduction of the diffusive transport properties, primarily due to exopolymeric substance production, may result in reduced methane attenuation due to limited O(2) -ingress.

  2. Impact of different plants on the gas profile of a landfill cover.

    PubMed

    Reichenauer, Thomas G; Watzinger, Andrea; Riesing, Johann; Gerzabek, Martin H

    2011-05-01

    Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa+grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa+grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content.

  3. Project identification for methane reduction options

    SciTech Connect

    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.

  4. Scrutinizing compost properties and their impact on methane oxidation efficiency.

    PubMed

    Huber-Humer, Marion; Tintner, Johannes; Böhm, Katharina; Lechner, Peter

    2011-05-01

    Methane emissions from active or closed landfills can be reduced by means of microbial methane oxidation enhanced by properly designed landfill covers and engineered biocovers. Composts produced using different waste materials have already been proven to support methane oxidation, and may represent a low-cost alternative to other suitable substrates such as sandy or humic-rich soils, which are frequently not available in sufficient amounts or are too costly. In the present study a data set of 30 different compost materials (different age and input materials) and mixtures, as well as seven soils and mineral substrates were tested to assess methane oxidation rate under similar conditions in a laboratory column set-up. Multivariate data analysis (discriminant analysis) was applied to predict the influence of 21 different parameters (chemical, maturation and physical) on methane oxidation rate in a PLS-DA model. The results show that bulk density, total nutrient content (nitrogen and phosphorus), as well as the quantity and quality (with respect to maturity) of organic matter determined methane oxidation rate in this data set. The model explained 50% of the data variation, indicating how characterisation of oxidation rate by single, even diverse conventional parameters was limited. Thus for the first time, Fourier Transform Infrared (FTIR) spectroscopy was applied to a series of samples to better determine the characteristics of methane-oxidising materials. The initial data obtained in this study appear to be most promising. The prediction of specific methane oxidation rate of a potential biocover material from FTIR spectra and multivariate data analyses is a target to be focused on in the future. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Methane cycling. Nonequilibrium clumped isotope signals in microbial methane.

    PubMed

    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

    2015-04-24

    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 (for example, (13)CH3D) has recently emerged as a proxy for determining methane-formation temperatures. However, the effect 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 (13)CH3D 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. Statistical characterization of spatiotemporal sediment dynamics in the Venice lagoon

    NASA Astrophysics Data System (ADS)

    Carniello, Luca; D'Alpaos, Andrea; Botter, Gianluca; Rinaldo, Andrea

    2016-05-01

    Characterizing the dynamics of suspended sediment is crucial when investigating the long-term evolution of tidal landscapes. Here we apply a widely tested mathematical model which describes the dynamics of cohesive and noncohesive sediments, driven by the combined effect of tidal currents and wind waves, using 1 year long time series of observed water levels and wind data from the Venice lagoon. The spatiotemporal evolution of the computed suspended sediment concentration (SSC) is analyzed on the basis of the "peak over threshold" theory. Our analysis suggests that events characterized by high SSC can be modeled as a marked Poisson process over most of the lagoon. The interarrival time between two consecutive over threshold events, the intensity of peak excesses, and the duration are found to be exponentially distributed random variables over most of tidal flats. Our study suggests that intensity and duration of over threshold events are temporally correlated, while almost no correlation exists between interarrival times and both durations and intensities. The benthic vegetation colonizing the central southern part of the Venice lagoon is found to exert a crucial role on sediment dynamics: vegetation locally decreases the frequency of significant resuspension events by affecting spatiotemporal patterns of SSCs also in adjacent areas. Spatial patterns of the mean interarrival of over threshold SSC events are found to be less heterogeneous than the corresponding patterns of mean interarrivals of over threshold bottom shear stress events because of the role of advection/dispersion processes in mixing suspended sediments within the lagoon. Implications for long-term morphodynamic modeling of tidal environments are discussed.

  7. Validation of Numerical Shallow Water Models for Tidal Lagoons

    SciTech Connect

    Eliason, D.; Bourgeois, A.

    1999-11-01

    An analytical solution is presented for the case of a stratified, tidally forced lagoon. This solution, especially its energetics, is useful for the validation of numerical shallow water models under stratified, tidally forced conditions. The utility of the analytical solution for validation is demonstrated for a simple finite difference numerical model. A comparison is presented of the energetics of the numerical and analytical solutions in terms of the convergence of model results to the analytical solution with increasing spatial and temporal resolution.

  8. Numerical modeling of the Patos Lagoon coastal plume, Brazil

    NASA Astrophysics Data System (ADS)

    Marques, W. C.; Fernandes, E. H.; Monteiro, I. O.; Möller, O. O.

    2009-03-01

    The Southern Brazilian Shelf (SBS) is a freshwater-influenced region, but studies on the dynamics of coastal plumes are sparse and lack in space-time resolution. Studies on the dynamics of the Patos Lagoon plume are even more limited. The aim of this paper is to investigate the influence of the principal physical forcing for the formation and behavior of the Patos Lagoon coastal plume. The study is carried out through 3D numerical modeling experiments and empirical orthogonal function (EOF) analysis. Results showed that the amount of freshwater is the principal physical forcing controlling the plume formation. The Coriolis effect enhances the northward transport over the shelf, while the tidal effects contribute to intensify horizontal and vertical mixing, which are responsible for spreading the freshwater over the shelf. The wind effect, on the other hand, is the main mechanism controlling the behavior of the Patos Lagoon coastal plume over the inner SBS in synoptic time scales. Southeasterly and southwesterly winds contribute to the northeastward displacement of the plume, breaking the vertical stratification of the inner continental shelf. Northeasterly and northwesterly winds favor ebb conditions in the Patos Lagoon, contributing to the southwestward displacement of the plume enhancing the vertical stratification along and across-shore. The EOF analysis reveals two modes controlling the variability of the plume on the surface. The first mode (explaining 70% of the variability) is associated to the southwestward transportation of the plume due to the dominance of north quadrant winds, while the second mode (explaining 19% of the variability) is associated to the intermittent migration of the plume northeastward due to the passage of frontal systems over the area. Large scale plumes can be expected during winter and spring months, and are enhanced during El Niño events.

  9. Heavy metals distribution in sediments of Nador lagoon (Morocco)

    NASA Astrophysics Data System (ADS)

    Bloundi, K.; Duplay, J.

    2003-04-01

    The Nador lagoon is a paralic system, located North-East of Morocco. At the present time this ecosystem undergoes an anthropic stress induced by urban, industrial and agricultural releases, and also by fishery activity which enriches this ecosystem in organic and inorganic wastes. A geochemical study has been undertaken, first to define the areas contaminated by heavy metals (Zn, Cu, Co, Cr and V), and second to caracterize the different mineral phases, which trap these elements. Sediment samples were collected on twenty-eight stations scattered all over the lagoon, and each core (30 cm) was subdivided in two horizons (surface and depth). Mineralogical analyses as well as major and trace elements analyses were performed on surface and deep sediments. The results on major element analyses (Si, Al, Ca, Mg, Na, P) show an enrichment in halite and phosphates in the surface sediments. This highlights on one hand, low water exchange rates between the lagoon and the Mediterranean sea, and on the other hand, an increase in organic releases related to the urban, agricultural and fishery activities. The highest concentrations in inorganic micro-pollutant were recorded N-E of the lagoon and close to Nador city. With reference to the geochemical background, it can be concluded that there is a slight contamination in heavy metals. Moreover, enrichment factor calculations (EF) for heavy metals point out an increase in metal elements as following: Zn>Co>Cr>V>Cu. Sequential extractions were performed to determine the behaviour of these micro-pollutants. Thus, it was shown that carbonates, oxides and phosphates are the preferential mineral phases for trapping these heavy metals.

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

    SciTech Connect

    Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

    2000-02-26

    Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, 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 both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional

  11. Helminth communities in eels Anguilla anguilla from Adriatic coastal lagoons in Italy.

    PubMed

    Di Cave, D; Berrilli, F; De Liberato, C; Orecchia, P; Kennedy, C R

    2001-03-01

    The composition and diversity of the total and intestinal component and infra-communities were determined in eels Anguilla anguilla from three shallow lagoons on the Adriatic coast of Italy to determine whether the helminth communities would differ in composition and structure from those in eels from lagoons on the Tyrrhenian coast. The lagoons differed in respect of their management regimes and the extent of freshwater influx. Both freshwater and marine species of helminths were found in the eels in all three lagoons, but the freshwater component was richer in Valle Figheri. A suite of three digenean eel specialist species occurred in all three lagoons, of which any two members dominated each community. This conferred a high degree of similarity between the communities of the three lagoons. The same three species also dominated helminth communities in eels in lagoons along the Tyrrhenian coast of Italy, and compositional similarity levels were similar within and between western and eastern groups. Species richness was higher in the component communities of the eels of the Adriatic lagoons when compared to the Tyrrhenian ones, but diversity and dominance indices were of a similar order of magnitude and range. Intestinal helminth communities were richer and more diverse in two of the Adriatic lagoons because the proportion of eels with zero or one helminth species was, unusually, in the minority. It was nevertheless concluded that infracommunity structure was similar in eels from both western and eastern lagoons and that the hypothesis that it would differ in Adriatic lagoons could not be supported. The findings provide further evidence of the similarity in composition and structure of helminth communities in eels from coastal lagoons throughout Europe.

  12. Municipal sewage treatment: Lagoons (ponds). (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations concerning the treatment and storage of municipal wastewater and sewage in lagoons. Lagoon design, operation, and associated equipment for pretreatment, treatment, and storage techniques are discussed. Many citations describe the water treatment facilities of specific cities, and provide evaluations of the operations at those sites. Industrial and other non-municipal wastewater treatment lagoons are referenced in a related bibliography. (Contains 250 citations and includes a subject term index and title list.)

  13. Municipal sewage treatment: Lagoons (ponds). (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-11-01

    The bibliography contains citations concerning the treatment and storage of municipal wastewater and sewage in lagoons. Lagoon design, operation, and associated equipment for pretreatment, treatment, and storage techniques are discussed. Many citations describe the water treatment facilities of specific cities, and provide evaluations of the operations at those sites. Industrial and other non-municipal wastewater treatment lagoons are referenced in a related bibliography. (Contains 250 citations and includes a subject term index and title list.)

  14. Industrial waste treatment: Lagoons (ponds). (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-01-01

    The bibliography contains citations concerning the treatment and storage of wastewaters in lagoons. Lagoon design, operation, associated equipment, and pretreatment processes are discussed. Included in the references are treatment of wastewaters from breweries, tanneries, paper mills, agricultural operations, and other industrial operations. Descriptions and evaluations of specific facilities are provided. Municipal water and sewage treatment lagoons are referenced in a related bibliography. (Contains a minimum of 118 citations and includes a subject term index and title list.)

  15. Geoelectrical signals of geologic and hydrologic processes in a fringing reef lagoon setting

    NASA Astrophysics Data System (ADS)

    Befus, Kevin M.; Cardenas, M. Bayani; Tait, Douglas R.; Erler, Dirk V.

    2014-09-01

    Coastal groundwater may discharge into nearshore and offshore waters forced by terrestrial fluxes, controlled by local geology, and modulated by the hydrodynamics of littoral water. We investigated the electrical signature of these features with a dense, multiscale network of electrical resistivity tomography (ERT) surveys in the Muri Lagoon of Rarotonga, Cook Islands. The ERT surveys spanned from onshore to 400 m into the lagoon and used standard electrodes on land and across the foreshore, submerged electrodes in the shallow subtidal zone, and floating electrodes towed throughout the reef lagoon by a boat. ERT surveys on land mapped a typical freshwater lens underlain by a saltwater wedge, but with possible deviations from the classical model due to an adjacent tidal creek. Further inland, ERT surveys imaged a layer of lava flow deposits that is potentially a confining hydrogeologic unit; this unit was used to constrain the expected electrical resistivity of these deposits below the lagoon. ERT surveys across the intertidal zone and into the lagoon indicated fresh groundwater and porewater salinity patterns consistent with previous small-scale studies including the seaward extension of fresh groundwater pathways to the lagoon. Electrical resistivity (ER) variations in the lagoon subsurface highlighted heterogeneities in the lagoon structure that may focus submarine groundwater discharge (SGD) through previously unknown buried lava flow deposits in the lagoon. A transition to higher ER values near the reef crest is consistent with the ER signature of porosity reduction due to ongoing differential cementation of reef deposits across the lagoon. The imaged coastal hydrostratigraphic heterogeneity may thus control terrestrial and marine porewater mixing, support SGD, and provide the pathways for groundwater and the materials it transports into the lagoon. This hydrogeophysical investigation highlighted the spatial heterogeneity of submarine coastal geology and its

  16. A reconnaissance approach for hydrology of atoll lagoons

    NASA Astrophysics Data System (ADS)

    Pagès, J.; Andréfouët, S.

    2001-12-01

    As a reconnaissance tool of the hydrology of atoll lagoons in the micro-tidal environment of the Tuamotu Archipelago, we define and compute "potential" flow rates at lagoon scale under three swell regimes (high, average, and low swell) after assessment of orientation and width of reef-flat spillways using satellite images. As a direct test, the "potential" flows were compared with field measurements of (1) measured inflows across the reef flat (for eight atolls), (2) net outgoing flow through the pass (for three atolls), and (3) lagoon-level variation rates (for four atolls). Absolute values of "potential" and field flows agreed ( r 2=0.94, n=42, slope ~1). Computed average water renewal times (TRAV) were also tested against concentrations of dissolved organic matter (DOM). DOM and TRAV were positively correlated ( r 2=0.54, n=26; Spearman's rs=0.54), and this relationship should enable the detection of unusual atolls. This approach would then appear to be useful for the reconnaissance of hydrodynamics processes in comparable micro-tidal environments.

  17. Modelling the salinization of a coastal lagoon-aquifer system

    NASA Astrophysics Data System (ADS)

    Colombani, N.; Mastrocicco, M.

    2017-08-01

    In this study, a coastal area constituted by alternations of saline-brackish lagoons and freshwater bodies was studied and modelled to understand the hydrological processes occurring between the lagoons, the groundwater system of the Po River Delta (Italy) and the Adriatic Sea. The contribution of both evaporation and anthropogenic factors on groundwater salinization was assessed by means of soil, groundwater and surface water monitoring. Highresolution multi-level samplers were used to capture salinity gradients within the aquifer and surface water bodies. Data were employed to calibrate a density-dependent numerical transport model implemented with SEAWAT code along a transect perpendicular to the coast line. The results show that the lagoon is hydraulically well connected with the aquifer, which provides the major source of salinity because of the upcoming of paleo-seawater from the aquitard laying at the base of the unconfined aquifer. On the contrary, the seawater (diluted by the freshwater river outflow) creates only a limited saltwater wedge. The increase in groundwater salinity could be of serious concern, especially for the pinewood located in the dune near the coast, sensitive to salinity increases. This case study represents an interesting paradigm for other similar environmental setting, where the assumption of classical aquifer salinization from a saltwater wedge intruding from the sea is often not representative of the actual aquifer’s salinization mechanisms.

  18. Coastal lagoons and their evolution: A hydromorphological perspective

    NASA Astrophysics Data System (ADS)

    Duck, Robert W.; da Silva, José Figueiredo

    2012-09-01

    From a geoscience perspective, coastal lagoons are essentially ephemeral features which are part of a continuum of coastal environments. Their natural hydromorphological evolution is seldom if ever permitted to take place as a consequence of human action; either directly by engineering interventions, to maintain or create navigable inlets, or indirectly due to activities within their catchment areas. The hydromorphological impacts of historical, contemporary and proposed engineering activities in coastal lagoons around in the world are reviewed and from these a powerful exemplar is that of the Aveiro system in Portugal. Here, two centuries of channelization, jetty and breakwater construction and progressive dredging have transformed a then fluvially dominant system into one that is today tidally dominant. Both the tidal range and tidal prism have increased along with the extent of saline intrusion. The associated stresses imposed by increased tidal currents have, in turn, led to important changes in the sedimentary regime and to the loss of almost all seagrass species which were once abundant in the system. This, along with observations from other related case studies, raises important questions regarding the concept of lagoon ecosystem 'health' and the baseline or reference conditions to which it is assessed.

  19. Saline landfill leachate disposal in facultative lagoons for wastewater treatment.

    PubMed

    Orta de Velasquez, M T; Monje-Ramirez, I; Yañez Noguez, I

    2012-01-01

    This study was carried out to determine the effect of disposing of saline landfill leachates in a Facultative Lagoon Wastewater Treatment Plant (FLWTP). The FLWTP is near a landfill and presents two characteristics: a wastewater influent with low organic matter, and high lagoon salinity due to the soil characteristics. These characteristics made the FLWTP a viable candidate to evaluate the feasibility of adding landfill leachates to the wastewater influent. Different mixtures of leachate with raw wastewater using volumetric ratios of 4%, 6%, and 10% (v/v) were evaluated in facultative lagoon reactors (FLRs). A 10% concentration of leachates in raw wastewater increased BOD5 and COD in the influent from 45 to 110 mg L(-1) and from 219 to 711 mg L(-1), respectively. It was found that the increase in salinity given by the raw wastewater and leachate mixture did not inhibit algae diversity. The types of algae present were Microcystis sp., Merismopedia sp., Euglena sp., Scenedesmus sp., Chlorella, Diatomea and Anacystis sp. However, decreased algae densities were observed, as measured by the decrease in chlorophyll concentration. The results showed that a 100% leachate concentration combined with wastewater did not upset biological treatment in the FLRs. Mean removal efficiencies for BOD5 and COD were 75% and 35%, respectively, giving a final BOD5 lower than 25 mg L(-1). There was also a significant decrease in the leachate heavy metal content when diluted with raw wastewater as result of natural precipitation.

  20. Plankton bioindicators of environmental conditions in coastal lagoons

    NASA Astrophysics Data System (ADS)

    Hemraj, Deevesh A.; Hossain, Md A.; Ye, Qifeng; Qin, Jian G.; Leterme, Sophie C.

    2017-01-01

    Coastal lagoons are characterised by strong spatial gradient of environmental parameters, especially hypersalinity, and are prone to anthropogenic disturbance. The Coorong (South Australia) is an inverse estuarine coastal lagoon separated from the sea by sand dunes. It is exposed to extreme water quality changes that affect its aquatic communities. Here, we used plankton as indicators of extreme environmental fluctuations to monitor and manage the environmental health of such complex systems. We defined the relationship of different plankton communities with water quality fluctuations and determined plankton species suitable for monitoring the ecosystem health. Two distinct communities of phytoplankton and zooplankton were identified, with salinity and nutrients being the principal factors impacting species distribution. Thus, two sets of indicator species were selected based on the different communities observed. Polychaete and gastropod larvae were positive indicators, showing salinity range restriction of brackish to marine. The distribution Acartia cf. fancetti represented healthy hypersaline conditions (salinity 40-60), while Cyclophora sp. and Scrippsiella sp. were negative indicators, correlating with extreme salinity and ammonia levels. The implementation of planktonic organisms as environmental indicators provided a constructive tool for the management of ecosystem health of the Coorong and will be applicable to similar coastal lagoons.

  1. Spatiotemporal variation of bacterial community composition and possible controlling factors in tropical shallow lagoons.

    PubMed

    Laque, Thaís; Farjalla, Vinicius F; Rosado, Alexandre S; Esteves, Francisco A

    2010-05-01

    Bacterial community composition (BCC) has been extensively related to specific environmental conditions. Tropical coastal lagoons present great temporal and spatial variation in their limnological conditions, which, in turn, should influence the BCC. Here, we sought for the limnological factors that influence, in space and time, the BCC in tropical coastal lagoons (Rio de Janeiro State, Brazil). The Visgueiro lagoon was sampled monthly for 1 year and eight lagoons were sampled once for temporal and spatial analysis, respectively. BCC was evaluated by bacteria-specific PCR-DGGE methods. Great variations were observed in limnological conditions and BCC on both temporal and spatial scales. Changes in the BCC of Visgueiro lagoon throughout the year were best related to salinity and concentrations of NO (3) (-) , dissolved phosphorus and chlorophyll-a, while changes in BCC between lagoons were best related to salinity and dissolved phosphorus concentration. Salinity has a direct impact on the integrity of the bacterial cell, and it was previously observed that phosphorus is the main limiting nutrient to bacterial growth in these lagoons. Therefore, we conclude that great variations in limnological conditions of coastal lagoons throughout time and space resulted in different BCCs and salinity and nutrient concentration, particularly dissolved phosphorus, are the main limnological factors influencing BCC in these tropical coastal lagoons.

  2. An integrated Pan-European perspective on coastal Lagoons management through a mosaic-DPSIR approach

    PubMed Central

    Dolbeth, Marina; Stålnacke, Per; Alves, Fátima L.; Sousa, Lisa P.; Gooch, Geoffrey D.; Khokhlov, Valeriy; Tuchkovenko, Yurii; Lloret, Javier; Bielecka, Małgorzata; Różyński, Grzegorz; Soares, João A.; Baggett, Susan; Margonski, Piotr; Chubarenko, Boris V.; Lillebø, Ana I.

    2016-01-01

    A decision support framework for the management of lagoon ecosystems was tested using four European Lagoons: Ria de Aveiro (Portugal), Mar Menor (Spain), Tyligulskyi Liman (Ukraine) and Vistula Lagoon (Poland/Russia). Our aim was to formulate integrated management recommendations for European lagoons. To achieve this we followed a DPSIR (Drivers-Pressures-State Change-Impacts-Responses) approach, with focus on integrating aspects of human wellbeing, welfare and ecosystem sustainability. The most important drivers in each lagoon were identified, based on information gathered from the lagoons’ stakeholders, complemented by scientific knowledge on each lagoon as seen from a land-sea perspective. The DPSIR cycles for each driver were combined into a mosaic-DPSIR conceptual model to examine the interdependency between the multiple and interacting uses of the lagoon. This framework emphasizes the common links, but also the specificities of responses to drivers and the ecosystem services provided. The information collected was used to formulate recommendations for the sustainable management of lagoons within a Pan-European context. Several common management recommendations were proposed, but specificities were also identified. The study synthesizes the present conditions for the management of lagoons, thus analysing and examining the activities that might be developed in different scenarios, scenarios which facilitate ecosystem protection without compromising future generations. PMID:26776151

  3. An integrated Pan-European perspective on coastal Lagoons management through a mosaic-DPSIR approach

    NASA Astrophysics Data System (ADS)

    Dolbeth, Marina; Stålnacke, Per; Alves, Fátima L.; Sousa, Lisa P.; Gooch, Geoffrey D.; Khokhlov, Valeriy; Tuchkovenko, Yurii; Lloret, Javier; Bielecka, Małgorzata; Różyński, Grzegorz; Soares, João A.; Baggett, Susan; Margonski, Piotr; Chubarenko, Boris V.; Lillebø, Ana I.

    2016-01-01

    A decision support framework for the management of lagoon ecosystems was tested using four European Lagoons: Ria de Aveiro (Portugal), Mar Menor (Spain), Tyligulskyi Liman (Ukraine) and Vistula Lagoon (Poland/Russia). Our aim was to formulate integrated management recommendations for European lagoons. To achieve this we followed a DPSIR (Drivers-Pressures-State Change-Impacts-Responses) approach, with focus on integrating aspects of human wellbeing, welfare and ecosystem sustainability. The most important drivers in each lagoon were identified, based on information gathered from the lagoons’ stakeholders, complemented by scientific knowledge on each lagoon as seen from a land-sea perspective. The DPSIR cycles for each driver were combined into a mosaic-DPSIR conceptual model to examine the interdependency between the multiple and interacting uses of the lagoon. This framework emphasizes the common links, but also the specificities of responses to drivers and the ecosystem services provided. The information collected was used to formulate recommendations for the sustainable management of lagoons within a Pan-European context. Several common management recommendations were proposed, but specificities were also identified. The study synthesizes the present conditions for the management of lagoons, thus analysing and examining the activities that might be developed in different scenarios, scenarios which facilitate ecosystem protection without compromising future generations.

  4. Environmental Assessment of the Bolinas Lagoon: a study utilizing benthic foraminifera

    NASA Astrophysics Data System (ADS)

    Benton, L.; Espinoza Madrid, N.; Grande, C.

    2016-12-01

    Benthic foraminifera have long been recognized for their utility in environmental assessments. They are abundant, diverse, and found in all marine environments, but species distributions depend largely on local environmental conditions. This study analyses benthic foraminiferal assemblages from the Bolinas Lagoon, Marin County, California. The Careers in Science Intern Program collected 36 sediment samples from 13 sites within the Bolinas Lagoon. Foraminiferal assemblages for each site are reported, and species richness, relative abundance, and Shannon's diversity calculated. Results indicate that Shannon's diversity is low throughout the Bolinas Lagoon and stress tolerant taxa are abundant, which suggests that current conditions in the Bolinas Lagoon are sub optimal.

  5. Organic carbon isotope ratios of recent sediments from coastal lagoons of the Gulf of Mexico, Mexico

    NASA Astrophysics Data System (ADS)

    Botello, Alfonso V.; Mandelli, Enrique F.; Macko, Steve; Parker, Patrick L.

    1980-03-01

    The stable carbon isotope composition sedimentary organic carbon was determined in the sediments of seven coastal lagoons of the Gulf of Mexico, Mexico. For most of the lagoons the δ13C values for sediments ranged from -20.1 to -23.9%. Anomalously low values, -26.8 to 29.3%. were determined in sediments of two of the studied lagoons, probably due to the presence of organic carbon from anthropogenic sources, naturally absent in these environments. The δ13C values determined in the tissues of oysters collected at the same time in the different lagoons were very similar to those recorded in the sediments.

  6. Decrease in herbicide concentrations and affected factors in lagoons located around Lake Biwa.

    PubMed

    Sudo, M; Nishino, M; Okubo, T

    2006-01-01

    The contamination levels and changes in the concentrations in four lagoons around Lake Biwa of paddy-use herbicide were studied. Four lagoons, Sone-numa (52 days of HRT (hydraulic residence time) estimated from the lagoon volume and the average discharge at the outlet, 21 ha area), Yanagihira-ko (40 days, 5.0 ha), Noda-numa (11 days, 6.0 ha), and Iba-naiko (2 days, 55.5 ha), were selected as monitoring sites. Intensive water sampling was carried out once a week from May to June at the outlet of each lagoon. Although twelve of the monitored herbicides were detected, the maximum concentrations did not exceed the guidelines for water-supply law in Japan. The relation between half-lives in herbicide concentrations and characteristics of a lagoon such as HRT and chlorophyll-a concentrations were examined. The shorter half-lives of herbicide concentrations in lagoons with shorter HRT means that replacement by influent water effectively decreased the pesticide concentrations. Shorter half-lives in lagoons with high chlorophyll-a concentrations between the lagoons with similar HRT suggest that biological degradation during the residence time worked more efficiently in the lagoon with high chlorophyll-a concentrations.

  7. Assessing the impact of animal waste lagoon seepage on the geochemistry of an underlying shallow aquifer.

    PubMed

    McNab, Walt W; Singleton, Michael J; Moran, Jean E; Esser, Brad K

    2007-02-01

    Evidence of seepage from animal waste holding lagoons at a dairy facility in the San Joaquin Valley of California is assessed in the context of a process geochemical model that addresses reactions associated with the formation of the lagoon water as well as reactions occurring upon the mixture of lagoon water with underlying aquifer material. Comparison of model results with observed concentrations of NH4+, K+, PO4(3-), dissolved inorganic carbon, pH, Ca2+, Mg2+, SO4(2-), Cl-, and dissolved Ar in lagoon water samples and groundwater samples suggests three key geochemical processes: (i) off-gassing of significant quantities of CO2 and CH4 during mineralization of manure in the lagoon water, (ii) ion exchange reactions that remove K+ and NH4+ from seepage water as it migrates into the underlying anaerobic aquifer material, and (iii) mineral precipitation reactions involving phosphate and carbonate minerals in the lagoon water in response to an increase in pH as well as in the underlying aquifer from elevated Ca2+ and Mg2+ levels generated by ion exchange. Substantial off-gassing from the lagoons is further indicated by dissolved argon concentrations in lagoon water samples that are below atmospheric equilibrium. As such, Ar may serve as a unique tracer for lagoon water seepage since under-saturated Ar concentrations in groundwater are unlikely to be influenced by any processes other than mechanical mixing.

  8. Coal Bed Methane Primer

    SciTech Connect

    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

  9. Sources and sinks of methane beneath polar ice

    NASA Astrophysics Data System (ADS)

    Priscu, J. C.; Adams, H. E.; Hand, K. P.; Dore, J. E.; Matheus-Carnevali, P.; Michaud, A. B.; Murray, A. E.; Skidmore, M. L.; Vick-Majors, T.

    2014-12-01

    Several icy moons of the outer solar system carry subsurface oceans containing many times the volume of liquid water on Earth and may provide the greatest volume of habitable space in our solar system. Functional sub-ice polar ecosystems on Earth provide compelling models for the habitability of extraterrestrial sub-ice oceans. A key feature of sub-ice environments is that most of them receive little to no solar energy. Consequently, organisms inhabiting these environments must rely on chemical energy to assimilate either carbon dioxide or organic molecules to support their metabolism. Methane can be utilized by certain bacteria as both a carbon and energy source. Isotopic data show that methane in Earth's polar lakes is derived from both biogenic and thermogenic sources. Thermogenic sources of methane in the thermokarst lakes of the north slope of Alaska yield supersaturated water columns during winter ice cover that support active populations of methanotrophs during the polar night. Methane in the permanently ice-covered lakes of the McMurdo Dry Valleys, Antarctica varies widely in concentration and is produced either by contemporary methanogenesis or is a relic from subglacial flow. Rate measurements revealed that microbial methane oxidation occurs beneath the ice in both the arctic and Antarctic lakes. The first samples collected from an Antarctic subglacial environment beneath 800 m of ice (Subglacial Lake Whillans) revealed an active microbial ecosystem that has been isolated from the atmosphere for many thousands of years. The sediments of Lake Whillans contained high levels of methane with an isotopic signature that indicates it was produced via methanogenesis. The source of this methane appears to be from the decomposition of organic carbon deposited when this region of Antarctica was covered by the sea. Collectively, data from these sub-ice environments show that methane transformations play a key role in microbial community metabolism. The discovery of

  10. Assessment of methane generation, oxidation, and emission in a subtropical landfill test cell.

    PubMed

    Moreira, João M L; Candiani, Giovano

    2016-08-01

    This paper presents results of a methane balance assessment in a test cell built in a region with a subtropical climate near São Paulo, Brazil. Measurements and calculations were carried out to obtain the total methane emission to the atmosphere, the methane oxidation rate in the cover, and the total methane generation rate in the test cell. The oxidation rate was obtained through a calculation scheme based on a vertical one-dimensional methane transport in the cover region. The measured maximum and mean methane fluxes to the atmosphere were 124.4 and 15.87 g m(-2) d(-1), respectively. The total methane generation rate obtained for the test cell was 0.0380 ± 0.0075 mol s(-1). The results yielded that 69 % of the emitted methane occurred through the central well and 31 % through the cover interface with the atmosphere. The evaluations of the methane oxidation fraction for localized conditions in the lateral embankment of the test cell yielded 0.36 ± 0.11, while for the whole test cell yielded 0.15 ± 0.10. These results conciliate localized and overall evaluations reported in the literature. The specific methane generation rate obtained for the municipal solid waste with an age of 410 days was 317 ± 62 mol year(-1) ton(-1). This result from the subtropical São Paulo region is lower than reported figures for tropical climates and higher than reported figures for temperate climates.

  11. The effect of floods on sediment contamination in a microtidal coastal lagoon: the lagoon of Lesina, Italy.

    PubMed

    D'Adamo, Raffaele; Specchiulli, Antonietta; Cassin, Daniele; Botter, Margherita; Zonta, Roberto; Fabbrocini, Adele

    2014-10-01

    The effects on the microtidal lagoon of Lesina of runoff and the discharge of water and material from agricultural activities were investigated combining chemical analyses of pollutants [11 metals and 16 priority polycyclic aromatic compounds (PAHs)], determination of organic matter and grain size, and performance of innovative ecotoxicological tests. For metals, enrichment factors >3 for arsenic, nickel, and copper (Cu) were observed in the eastern zone of the lagoon, which is affected by nearby urban activities with discharge of water and domestic waste and by agricultural input with waters rich in fertilizers. Cu was correlated with no other metal, and its high concentrations (≤77 µg g(-1)) may result from the use of Cu-based fungicides in vineyards. Total PAHs (2,230 ± 3,150 ng g(-1)) displayed a wide range of concentrations with hot spots near freshwater inputs from the part of the catchment area exploited for wheat crops. Pyrolitic contamination also emerged, with higher-mass PAH congeners, such as asphalt, bitumen or coal, usually present in higher fractions as the dominant components. Ecotoxicological evaluations recorded moderate to high toxicity levels; the innovative MOT test bioassay showed good discriminatory ability because it identified a lagoon area whose inputs mainly depend on agricultural activities and which is impacted by metals rather than PAHs. Floods during periods of heavy rain and the discharge of water and material from agricultural activities may impact vulnerable systems, such as the lagoon of Lesina, where the presence of hot spots with remarkably high pollution values was observed.

  12. Methane excess in Arctic surface water-triggered by sea ice formation and melting.

    PubMed

    Damm, E; Rudels, B; Schauer, U; Mau, S; Dieckmann, G

    2015-11-10

    Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas.

  13. Methane excess in Arctic surface water- triggered by sea ice formation and melting

    PubMed Central

    Damm, E.; Rudels, B.; Schauer, U.; Mau, S.; Dieckmann, G.

    2015-01-01

    Arctic amplification of global warming has led to increased summer sea ice retreat, which influences gas exchange between the Arctic Ocean and the atmosphere where sea ice previously acted as a physical barrier. Indeed, recently observed enhanced atmospheric methane concentrations in Arctic regions with fractional sea-ice cover point to unexpected feedbacks in cycling of methane. We report on methane excess in sea ice-influenced water masses in the interior Arctic Ocean and provide evidence that sea ice is a potential source. We show that methane release from sea ice into the ocean occurs via brine drainage during freezing and melting i.e. in winter and spring. In summer under a fractional sea ice cover, reduced turbulence restricts gas transfer, then seawater acts as buffer in which methane remains entrained. However, in autumn and winter surface convection initiates pronounced efflux of methane from the ice covered ocean to the atmosphere. Our results demonstrate that sea ice-sourced methane cycles seasonally between sea ice, sea-ice-influenced seawater and the atmosphere, while the deeper ocean remains decoupled. Freshening due to summer sea ice retreat will enhance this decoupling, which restricts the capacity of the deeper Arctic Ocean to act as a sink for this greenhouse gas. PMID:26553610

  14. Seasonal Variation of the Macrozoobenthic Community Structure at Low Salinities in a Mediterranean Lagoon (Monolimni Lagoon, Northern Aegean)

    NASA Astrophysics Data System (ADS)

    Kevrekidis, Theodoros

    2004-09-01

    The macrozoobenthic community structure and dynamics at low salinities (0.3-6 psu) in a Mediterranean lagoon (Monolimni lagoon) were investigated. Samples were collected monthly from February 1998 to February 1999 at two sampling stations. Community structure was analyzed by means of uni- and multivariate methods. 21 taxa were collected; the amphipod Corophium orientale and the gastropod Ventrosia maritima dominated the assemblages. Total abundance peaked (50,000-60,000 individuals m-2) in mid or late autumn. Community structure showed an almost even seasonal periodicity; seasonal changes were mainly derived from the intense variation in abundance of most species and the non-occurrence of a few ones (e.g. Corophium insidiosum, Polydora ciliata) in spring and summer. Non- occurrence, which led to a depression of the most diversity indices, was possibly the only direct impact of the extremely low salinities (~0.3 psu) on community structure. The main structuring factors of the community in the deeper outer part of the lagoon were water temperature and depth, and in the innermost part, where a Ruppia maritima meadow occurred, were water temperature and predation pressure by crabs (Carcinus aestuarii) and gobies (Knipowitchia caucasica). A temporary decline in total abundance in summer followed an increase in abundance of these predators. (

  15. Temporal distribution of intertidal macrozoobenthic assemblages in a Nanozostera noltii-dominated area (Lagoon of Venice).

    PubMed

    Tagliapietra, D; Pessa, G; Cornello, M; Zitelli, A; Magni, P

    2016-03-01

    We describe the temporal distribution of intertidal macrozoobenthic assemblages in a small marsh pond of the Lagoon of Venice colonized by the seagrass Nanozostera noltii (Hornemman) Tomlinson et Posluzny. Three stations ranging in the degree of N. noltii cover were selected about 100 m apart and sampled 9 times at regular intervals from March 1996 to March 1997. We applied the concepts of resistance and resilience to "natural stress" (e.g. extent of protection from seagrass meadows, exposure of macrozoobenthic assemblages to high temperatures in summer) with the aim to assess the stability of a community along a gradient of seagrass coverage. Results showed that the most structured and taxa-rich macrozoobenthic assemblage occurred at the station covered by a continuous stand of N. noltii, where permanent taxa (i.e. found in 100% of samples) were almost double than those found at the other stations. During the annual cycle, the macrozoobenthic assemblages showed a cyclical pattern, with temporal fluctuations increasing as they moved further away from the seagrass beds. We propose the role of N. noltii offering structural complexity and stability as the more probable explanation to the observed differences between stations in the intertidal assemblages.

  16. Methane/nitrogen separation process

    DOEpatents

    Baker, R.W.; Lokhandwala, K.A.; Pinnau, I.; Segelke, S.

    1997-09-23

    A membrane separation process is described for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. The authors have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen. 11 figs.

  17. Methane/nitrogen separation process

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.; Pinnau, Ingo; Segelke, Scott

    1997-01-01

    A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

  18. Methanogens, Methane and Gastrointestinal Motility

    PubMed Central

    Triantafyllou, Konstantinos; Chang, Christopher

    2014-01-01

    Anaerobic fermentation of the undigested polysaccharide fraction of carbohydrates produces hydrogen in the intestine which is the substrate for methane production by intestinal methanogens. Hydrogen and methane are excreted in the flatus and in breath giving the opportunity to indirectly measure their production using breath testing. Although methane is detected in 30%-50% of the healthy adult population worldwide, its production has been epidemiologically and clinically associated with constipation related diseases, like constipation predominant irritable bowel syndrome and chronic constipation. While a causative relation is not proven yet, there is strong evidence from animal studies that methane delays intestinal transit, possibly acting as a neuromuscular transmitter. This evidence is further supported by the universal finding that methane production (measured by breath test) is associated with delayed transit time in clinical studies. There is also preliminary evidence that antibiotic reduction of methanogens (as evidenced by reduced methane production) predicts the clinical response in terms of symptomatic improvement in patients with constipation predominant irritable bowel syndrome. However, we have not identified yet the mechanism of action of methane on intestinal motility, and since methane production does not account for all constipation associated cases, there is need for high quality clinical trials to examine methane as a biomarker for the diagnosis or as a biomarker that predicts antibiotic treatment response in patients with constipation related disorders. PMID:24466443

  19. On methane pyrolysis special applications

    NASA Astrophysics Data System (ADS)

    Toncu, D. C.; Toncu, G.; Soleimani, S.

    2015-11-01

    Methane pyrolysis represents one of the most important processes in industrial use, with applications rising from the chemical and petrochemical industry, combustion, materials and protective coatings. Despite the intense research, experimental data lack kinetic aspects, and the thermodynamics involved often leads to inaccurate results when applied to various systems. Carrying out a comparative analysis of several available data on methane pyrolysis, the paper aims to study the phenomenon of methane pyrolysis under different environments (combustion and plasma), concluding on the most possible reaction pathways involved in many of its applications. Computer simulation using different database underlines the conclusion, helping to the understanding of methane pyrolysis importance in future technologies.

  20. Biological and biochemical methane reactions

    NASA Astrophysics Data System (ADS)

    Dalton, H.; Pienkos, P. T.; Stirling, D. I.

    1989-04-01

    The purpose of the project was to characterize the nature of the active site involved in methane activation by enzymes from well characterized and newly isolated methane-oxidizing bacteria. Kinetic and structural studies provided an initial picture of how the soluble methane monooxygenase (MMO) enzyme is structured and operates to selectively oxidize methane to methanol under ambient conditions. Cloning and sequencing of gene coding for some of the sMMO proteins were completed, and 72 strains of methanotrophs were isolated from extreme environments.

  1. Redefining the isotopic boundaries of biogenic methane: Methane from endoevaporites

    NASA Astrophysics Data System (ADS)

    Tazaz, Amanda M.; Bebout, Brad M.; Kelley, Cheryl A.; Poole, Jennifer; Chanton, Jeffrey P.

    2013-06-01

    The recent reports of methane in the atmosphere of Mars, as well as the findings of hypersaline paleoenvironments on that planet, have underscored the need to evaluate the importance of biological (as opposed to geological) trace gas production and consumption, particularly in hypersaline environments. Methane in the atmosphere of Mars may be an indication of extant life, but it may also be a consequence of geologic activity and/or the thermal alteration of ancient organic matter. On Earth these methane sources can be distinguished using stable isotopic analyses and the ratio of methane (C1) to C2 and C3 alkanes present in the gas source (C1/(C2 + C3)). We report here that methane produced in hypersaline environments on Earth has an isotopic composition and alkane content outside the values presently considered to indicate a biogenic origin. Methane-rich bubbles released from sub-aqueous substrates contained δ13CCH4 and δ2HCH4 values ranging from -65‰ to -35‰ and -350‰ to -140‰ respectively. Higher salinity endoevaporites yielded what would be considered non-biogenic methane based upon stable isotopic and alkane content, however incubation of crustal and algal mat samples resulted in methane production with similar isotopic values. Radiocarbon analysis indicated that the production of the methane was from recently fixed carbon. An extension of the isotopic boundaries of biogenic methane is necessary in order to avoid the possibility of false negatives returned from measurements of methane on Mars and other planetary bodies.

  2. Fish fauna recovery in a newly re-flooded Mediterranean coastal lagoon

    NASA Astrophysics Data System (ADS)

    Koutrakis, Emmanuil; Sylaios, Georgios; Kamidis, Nikolaos; Markou, Dimitrios; Sapounidis, Argyris

    2009-08-01

    Drana Lagoon, located at the NW site of Evros River Delta, was drained in 1987 and re-flooded in 2004 within the framework of an integrated wetland restoration project. This study presents the results of a monitoring program of the lagoon's oceanographic, water quality and fish fauna characteristics, during the pre- and post-restoration period. Results depict the presence of high salinity water (up to 41) due to seawater intrusion, strong evaporation in its interior and inadequate freshwater inflows. Overall, nutrient levels were low depicting local changes. Tidal variability at the mouth was approximately 0.2 m, producing high velocity tidal currents (up to 0.75 m/s). Eleven fish fauna species were collected; seven species were caught in both the inlet channel and the lagoon during the pre-restoration period and nine species in the post-restoration period. Atherina boyeri (37.6%) and Pomatoschistus marmoratus (31.7%) dominated the lagoon during the post-restoration period. Most of the A. boyeri specimens (88.5%) were caught inside the lagoon, while P. marmoratus had an almost