The Role of Terrestrial Inputs of Organic Matter in Arctic Lagoons: Comparative Studies from Open-Water and Ice-Covered Periods

NASA Astrophysics Data System (ADS)

Dunton, K. H.; McClelland, J. W.; Connelly, T.; Linn, S.; Khosh, M.

2012-12-01

Coastal ecosystems of the Arctic receive extraordinarily large quantities of terrestrial organic matter through river discharge and shoreline erosion. This organic matter, both in dissolved and particulate form, may provide an important carbon and energy subsidy that supports and maintains heterotrophic activity and food webs in coastal waters, especially in the lagoons. Recent food web studies using stable isotopes confirm the significant assimilation of terrestrial organic matter, based on the depletion in both 13C and 15N content of invertebrate and vertebrate consumers collected in eastern Beaufort Sea lagoons vs. offshore waters. Our current work specifically focuses on a set of 12 field sites along the eastern Alaskan Beaufort Sea coast, from Barter Island to Demarcation Bay. To examine linkages between biological communities and organic matter inputs from land, we compared sites ranging from lagoons to open coastal systems that receive differing amounts of freshwater runoff and also differ markedly in their exchange characteristics with shelf waters. Our temporal and spatial effort included field sampling during the ice covered period in a number of lagoons characterized by differences in their exchange characteristics with the nearshore shelf. Our preliminary chemical and biological measurements, the first of their kind in arctic coastal lagoons, reveal that lagoon benthos can become hypersaline (43) and net heterotrophic (values to 30% oxygen saturation) during winter, before rebounding during the period of ice break-up to net autotrophic (>100% saturation) under continued hypersaline conditions. Measurements of water and sediment chemistry, benthic and water column community characteristics, and natural abundance isotopic tracers promise to reveal the dynamic nature of these productive lagoon ecosystems under different hydrologic conditions. The possible role of terrestrially derived carbon to arctic estuarine food webs is especially important in view of

Methane fluxes during the cold season: distribution and mass transfer in the snow cover of bogs

NASA Astrophysics Data System (ADS)

Smagin, A. V.; Shnyrev, N. A.

2015-08-01

Fluxes and profile distribution of methane in the snow cover and different landscape elements of an oligotrophic West-Siberian bog (Mukhrino Research Station, Khanty-Mansiisk autonomous district) have been studied during a cold season. Simple models have been proposed for the description of methane distribution in the inert snow layer, which combine the transport of the gas and a source of constant intensity on the soil surface. The formation rates of stationary methane profiles in the snow cover have been estimated (characteristic time of 24 h). Theoretical equations have been derived for the calculation of small emission fluxes from bogs to the atmosphere on the basis of the stationary profile distribution parameters, the snow porosity, and the effective methane diffusion coefficient in the snow layer. The calculated values of methane emission significantly (by 2-3 to several tens of times) have exceeded the values measured under field conditions by the closed chamber method (0.008-0.25 mg C/(m2 h)), which indicates the possibility of underestimating the contribution of the cold period to the annual emission cycle of bog methane.

Spring and Summer Proliferation of Floating Macroalgae in a Mediterranean Coastal Lagoon (Tancada Lagoon, Ebro Delta, NE Spain)

NASA Astrophysics Data System (ADS)

Menéndez, M.; Comín, F. A.

2000-08-01

During the last 10 years, a drastic change in the structure of the community of primary producers has been observed in Tancada Lagoon (Ebro Delta, NE Spain). This consisted of a decrease in the abundance of submerged rooted macrophyte cover and a spring and summer increase in floating macroalgae. Two spatial patterns have been observed. In the west part of the lagoon, Chaetomorpha linum Kützing, dominated during winter and decreased progressively in spring when Cladophora sp. reached its maximum development. In the east part of the lagoon, higher macroalgal diversity was observed, together with lower cover in winter and early spring. Cladophora sp., Gracilaria verrucosa Papenfuss and Chondria tenuissima Agardh, increased cover and biomass in summer. Maximum photosynthetic production was observed in spring for G. verrucosa (10·9 mg O 2 g -1 DW h -1) and C. tenuissima (19·0 mg O 2 g -1 DW h -1) in contrast with Cladophora sp. (15·9 mg O 2 g -1 DW h -1) and Chaetomorpha linum (7·2 mg O 2 g -1 DW h -1) which reached maximum production in summer. Increased conductivity from reduced freshwater inflow, and higher water temperatures during periods of lagoon isolation, mainly in summer, were the main physical factors associated with an increase in floating macroalgal biomass across the lagoon. Reduced nitrogen availability and temperature-related changes in carbon availability during summer were related to a decrease in abundance of C. linum and increases in G. verrucosa and Cladophora sp.

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 undermore » similar conditions.« less

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 ...

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

Methane Emissions Estimation from a Dairy Farm using Eddy Covariance Measurements

NASA Astrophysics Data System (ADS)

Guo, Q.; Richardson, S.; Sokol, A. B.; Lauvaux, T.; Hristov, A. N.; Hong, B.; Davis, K. J.

2017-12-01

Dairy farms are a significant source of methane emissions. Accurate quantification of these emissions is important for evaluating and ultimately minimizing the impact of agricultural activity on climate change. We have employed the eddy covariance (EC) technique to attempt to quantify total CH4 emissions from a dairy farm, and compare these emissions to inventory estimates. An eddy covariance (EC) sensor was deployed to monitor CH4 emissions at one dairy manure storage facility from July 2016 through the winter of 2017, at a second manure storage facility from April to mid-July 2017, and at dairy barns during July and August of 2017. A flux footprint model was used to convert the observed methane fluxes into estimates of emissions per unit area from these sources. During April and May, CH4 fluxes from the second lagoon were relatively small and slowly increased with daily mean values growing from 0.45 to 10.75 μmol m-2 s-1. June to mid-July fluxes increased rapidly with a peak daily mean emission of 77.97 μmol m-2 s-1. The fluxes were positively correlated with air temperature. Comparison of emissions from the two lagoons, comparison to an inventory estimate of emissions from these lagoons, and evaluation of methane emissions from the barns are underway. These results will be combined to evaluate total farm emissions, and to test our understanding of the factors that govern emissions from dairy operations.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroth, M.H., E-mail: martin.schroth@env.ethz.ch; Eugster, W.; Gomez, K.E.

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 microorganismsmore » 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

Localised and limited impact of a dredging operation on coral cover in the northwestern lagoon of New Caledonia.

PubMed

Adjeroud, Mehdi; Gilbert, Antoine; Facon, Mathilde; Foglia, Marion; Moreton, Benjamin; Heintz, Tom

2016-04-15

We report here an interannual survey (2006-2012) of coral cover in the northwestern lagoon of New Caledonia, to assess the impact of an important dredging operation (August 2008-February 2010) associated with the construction of the largest nickel mining site in the Pacific. A BACI (Before-After Control-Impact) analysis failed to detect any significant interaction between period (before, during, and after dredging) and the category of the stations (impact vs. control). Among the 31 stations surveyed, only seven showed decreasing coral cover during the study period, mainly due to a decline in Acroporidae. However, the relationship between the dredging and this decrease was highly plausible only for one station, situated 0.9km from the dredging site. High hydrodynamism in the study area, the abundance of resistant corals and efficient protective measures during the dredging operation might explain these localised and limited impacts. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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...

Methane oxidation and attenuation of sulphur compounds in landfill top cover systems: Lab-scale tests.

PubMed

Raga, Roberto; Pivato, Alberto; Lavagnolo, Maria Cristina; Megido, Laura; Cossu, Raffaello

2018-03-01

In this study, a top cover system is investigated as a control for emissions during the aftercare of new landfills and for old landfills where biogas energy production might not be profitable. Different materials were studied as landfill cover system in lab-scale columns: mechanical-biological pretreated municipal solid waste (MBP); mechanical-biological pretreated biowaste (PB); fine (PBS f ) and coarse (PBS c ) mechanical-biological pretreated mixtures of biowaste and sewage sludge, and natural soil (NS). The effectiveness of these materials in removing methane and sulphur compounds from a gas stream was tested, even coupled with activated carbon membranes. Concentrations of CO 2 , CH 4 , O 2 , N 2 , H 2 S and mercaptans were analysed at different depths along the columns. Methane degradation was assessed using mass balance and the results were expressed in terms of methane oxidation rate (MOR). The highest maximum and mean MOR were observed for MBP (17.2gCH 4 /m 2 /hr and 10.3gCH 4 /m 2 /hr, respectively). Similar values were obtained with PB and PBS c . The lowest values of MOR were obtained for NS (6.7gCH 4 /m 2 /hr) and PBS f (3.6gCH 4 /m 2 /hr), which may be due to their low organic content and void index, respectively. Activated membranes with high load capacity did not seem to have an influence on the methane oxidation process: MBP coupled with 220g/m 2 and 360g/m 2 membranes gave maximum MOR of 16.5gCH 4 /m 2 /hr and 17.4gCH 4 /m 2 /hr, respectively. Activated carbon membranes proved to be very effective on H 2 S adsorption. Furthermore, carbonyl sulphide, ethyl mercaptan and isopropyl mercaptan seemed to be easily absorbed by the filling materials. Copyright © 2017. Published by Elsevier B.V.

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

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

2017-11-01

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 (CO 2 ) and reactant (CH 4 ) by CO 2 /CH 4 -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 CO 2 /CH 4 -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. CO 2 /CH 4 -ratios were also in good agreement with mass balance. In general, highest values for biodegradation were determined from mass balance, followed by CO 2 /CH 4 -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 CH 4 loads of 35-65gm -2 d -1 that are typical in the aftercare phase of landfills. Finally, data from stable isotope analysis and the CO 2 /CH 4 -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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albanna, Muna, E-mail: muna.albanna@gju.edu.j; 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 themore » 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.« less

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.

Characterization of a Mud Deposit Offshore of the Patos Lagoon, Southern Brazil

DTIC Science & Technology

2009-02-01

Journal Article 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Characterization of mud deposit offshore of the Patos lagoon, southern Brazil 5a...deposition of mud on the beach along the shoreface of Rio Grande do Sul, Brazil dramatically influences the normal operations in the littoral zone...Continental Shelf Research journal homepage: www.elsevier.com/locate/csr Characterization of a mud deposit offshore of the Patos Lagoon, southern Brazil

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.

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

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

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.

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.

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.

Carbon and hydrogen isotopic systematics of dissolved methane in small seasonally ice-covered lakes near the margin of the Greenland ice sheet

NASA Astrophysics Data System (ADS)

Cadieux, S. B.; White, J. R.; Pratt, L. M.; Peng, Y.; Young, S. A.

2013-12-01

Northern lakes contribute from 6-16% of annual methane inputs to Earth's atmosphere, yet little is known about the seasonal biogeochemistry of CH4 cycling, particularly for lakes in the Arctic. Studies during ice-free conditions have been conducted in Alaskan, Swedish and Siberian lakes. However, there is little information on CH4 cycling under ice-covered conditions, and few stable isotopic measurements, which can help elucidate production and consumption pathways. In order to better understand methane dynamics of ice-covered Arctic lakes, 4 small lakes (surface area <1 km2) within a narrow valley extending from the Russells Glacier to Søndre Strømfjord in Southwestern Greenland were examined during summer stratification and winter ice-cover. Lakes in the study area are ice-covered from mid-September to mid-June. In both seasons, variations in the concentrations and isotopic composition of methane with depth were related to redox fluctuations. During late winter under~2 m of ice, the entire water column was anoxic with wide variation in methane concentrationsand isotopic composition from lake to lake. In three of the lakes, CH4 concentrations and δ13C were relatively stable over the depth of the water column, averaging from 120 to 480μM, with δ13CH4 values from -56‰ to -66‰, respectively. Methane concentrations in the other lake increased with depth from <1 μM below the ice to 800 μM at the sediment/water interface, while δ13C decreased by 30‰ from -30‰ to -70‰ over this depth. In all the lakes, δ13C of sediment porewater was lighter than the overlying water by at least 10‰. The δD-CH4 in the water column ranged from -370‰ to -50‰, exhibiting covariance with δ13C consistent with significant methanotrophic activity. In the sediment, δD-CH4 values ranged from -330‰ to -275‰, and were inversely correlated with δ13C. We will present detailed information on redox dynamics as a controlling factor in methane cycling, and explore the

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

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.

Patterns of in-soil methane production and atmospheric emission among different land covers of a Lake Erie estuarine wetland

NASA Astrophysics Data System (ADS)

Rey Sanchez, C.; Morin, T. H.; Stefanik, K. C.; Angle, J.; Wrighton, K. C.; Bohrer, G.

2017-12-01

Wetland soils store a great amount of carbon, but also accumulate and emit methane (CH4), a powerful greenhouse gas. To better understand the vertical and horizontal spatial variability of CH4 emissions, we monitored production and fluxes of CH4 in Old Woman Creek, an estuarine wetland of Lake Erie, Ohio, during the growing seasons of 2015 and 2016. Our combined observation methods targeted three different scales: 1) the eddy covariance technique provided continuous high frequency observations integrated over a large spatial footprint; 2) monthly chamber measurements provided sparse point measurements of fluxes in four distinct land-cover types in the wetland: open water, emergent vegetation (Typha spp.), floating vegetation (Nelumbo spp.) and mud flats; and 3) in-situ porewater dialysis samplers, "peepers", provided vertical CH4 concentration data in the soil at the same locations and temporal time steps as the chambers. In addition, we studied gene transcripts to quantify methanogenesis activity along the vertical soil profile. Using integrated chamber and EC measurements, we found an average surface emission rate from Typha, the most abundant vegetated land cover, of 219.4 g CH4-C m-2 y-1, which was much higher than rates reported in similar emergent vegetation types in other wetlands. There was large spatial variation of flux rates, with mud flats having the highest rates of CH4 emission, followed by Nelumbo and Typha patches, and with open water having the lowest emissions. Within the soil column, we applied a numerical model to convert soil methane concentrations to emissions rates. We found that, contrary to current ideas of methane production, most methane was being produced in the well-oxygenated surface soils, probably in anoxic microsites within the oxic layer. Our metatranscriptomic data supported these findings, clearly showing nine times greater methanogenic activity in oxic surface soils relative to deeper anoxic soils. Combined, our results provide

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

Lagoon Restoration Project: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

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 systemsmore » 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.« less

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.

Brazil: Duck Lagoon

Atmospheric Science Data Center

2013-04-18

article title:  Brazil - The Duck Lagoon     View Larger Image ... 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 ...

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 ...

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.

Subtidal hydrodynamics in a tropical lagoon: A dimensionless numbers approach

NASA Astrophysics Data System (ADS)

Tenorio-Fernandez, L.; Valle-Levinson, A.; Gomez-Valdes, J.

2018-01-01

Observations in a tropical lagoon of the Yucatan peninsula motivated a non-dimensional number analysis to examine the relative influence of tidal stress, density gradients and wind stress on subtidal hydrodynamics. A two-month observation period in Chelem Lagoon covered the transition from the dry to the wet season. Chelem Lagoon is influenced by groundwater inputs and exhibits a main sub-basin (central sub-basin), a west sub-basin and an east sub-basin. Subtidal hydrodynamics were associated with horizontal density gradients that were modified seasonally by evaporation, precipitation, and groundwater discharge. A tidal Froude number (Fr0), a Wedderburn number (W), and a Stress ratio (S0) were used to diagnose the relative importance of dominant subtidal driving forces. The Froude number (Fr0) compares tidal forcing and baroclinic forcing through the ratio of tidal stress to longitudinal baroclinic pressure gradient. The Wedderburn number (W) relates wind stress to baroclinicity. The stress ratio (S0) sizes tidal stress and wind stress. S0 is a new diagnostic tool for systems influenced by tides and winds, and represents the main contribution of this research. Results show that spring-tide subtidal flows in the tropical lagoon had log(Fr0) ≫ 0 and log(S0) > 0 , i.e., driven mainly by tidal stresses (advective accelerations). Neap tides showed log(Fr0) ≪ 0 and log(S0) < 0) , i.e., flows driven by baroclinicity, especially at the lagoon heads of the east and west sub-basins. However, when the wind stress intensified over the lagoon, the relative importance of baroclinicity decreased and the wind stress controlled the dynamics (log(W) ≫ 0). Each sub-basin exhibited a different subtidal response, according to the dimensionless numbers. The response depended on the fortnightly tidal cycle, the location and magnitude of groundwater input, and the direction and magnitude of the wind stress.

An Analysis of Shoreline Change At Little Lagoon, Alabama

DTIC Science & Technology

2006-06-14

AN ANALYSIS OF SHORELINE CHANGE AT LITTLE LAGOON, ALABAMA By Glen R. Gibson THESIS...control number. 1. REPORT DATE 14 JUN 2006 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE An Analysis Of Shoreline Change At...correlation analysis conducted on the gulf shoreline and Little Lagoon’s southern shoreline showed that although weak overall correlation values

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

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

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). Copyright © 2012 Elsevier Ltd. All rights reserved.

A simulation model for methane emissions from landfills with interaction of vegetation and cover soil.

PubMed

Bian, Rongxing; Xin, Danhui; Chai, Xiaoli

2018-01-01

Global climate change and ecological problems brought about by greenhouse gas effect have become a severe threat to humanity in the 21st century. Vegetation plays an important role in methane (CH 4 ) transport, oxidation and emissions from municipal solid waste (MSW) landfills as it modifies the physical and chemical properties of the cover soil, and transports CH 4 to the atmosphere directly via their conduits, which are mainly aerenchymatous structures. In this study, a novel 2-D simulation CH 4 emission model was established, based on an interactive mechanism of cover soil and vegetation, to model CH 4 transport, oxidation and emissions in landfill cover soil. Results of the simulation model showed that the distribution of CH 4 concentration and emission fluxes displayed a significant difference between vegetated and non-vegetated areas. CH 4 emission flux was 1-2 orders of magnitude higher than bare areas in simulation conditions. Vegetation play a negative role in CH 4 emissions from landfill cover soil due to the strong CH 4 transport capacity even though vegetation also promotes CH 4 oxidation via changing properties of cover soil and emitting O 2 via root system. The model will be proposed to allow decision makers to reconsider the actual CH 4 emission from vegetated and non-vegetated covered landfills. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial Variation in Development of Epibenthic Assemblages in a Coastal Lagoon

NASA Astrophysics Data System (ADS)

Benedetti-Cecchi, L.; Rindi, F.; Bertocci, I.; Bulleri, F.; Cinelli, F.

2001-05-01

Spatial and temporal patterns in colonization of epibenthic assemblages were measured in a coastal lagoon on the west coast of Italy using recruitment panels. It was proposed that if the ecological processes influencing development of assemblages were homogeneous within the lagoon, then there should be no differences in mean cover of colonists nor in spatial patterns of variance in abundance in different areas of the lagoon. In contrast, heterogeneity in ecological processes affecting development would be revealed by spatial variability in colonization. To test these hypotheses, two sticks each with five replicate panels were placed 3-5 m apart in each of two sites 30-100 m apart in each of three locations 500-100 m apart; the experiment was repeated three times between April and December 1999, using new sites at each location each time. The results revealed considerable spatial variation in the structure of developing assemblages across locations. There were significant Location or Time×Location effects in the mean abundance of common taxa, such as Enteromorpha intestinalis , Ulva rigida, Cladophora spp., bryozoans and serpulids. Patterns in spatial variation differed among locations for these organisms. Collectively, the results supported a model of spatial heterogeneity in intensity of processes influencing patterns of recruitment and development of epibenthic assemblages in the Lagoon of Orbetello. The implications of these results for management of environmental problems in complex, variable habitats such as coastal lagoons, are discussed.

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

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Collection Efficiencies of Anaerobic..., Table JJ-6 Table JJ-6 to Subpart JJ of Part 98—Collection Efficiencies of Anaerobic Digesters Anaerobic digester type Cover type Methane collection efficiency Covered anaerobic lagoon (biogas capture) Bank to...

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.

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrison, Bridger

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. Themore » 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.« less

Groundwater-driven nutrient inputs to coastal lagoons: The relevance of lagoon water recirculation as a conveyor of dissolved nutrients.

PubMed

Rodellas, Valentí; Stieglitz, Thomas C; Andrisoa, Aladin; Cook, Peter G; Raimbault, Patrick; Tamborski, Joseph J; van Beek, Pieter; Radakovitch, Olivier

2018-06-16

Evaluating the sources of nutrient inputs to coastal lagoons is required to understand the functioning of these ecosystems and their vulnerability to eutrophication. Whereas terrestrial groundwater processes are increasingly recognized as relevant sources of nutrients to coastal lagoons, there are still limited studies evaluating separately nutrient fluxes driven by terrestrial groundwater discharge and lagoon water recirculation through sediments. In this study, we assess the relative significance of these sources in conveying dissolved inorganic nutrients (NO 3 - , NH 4 + and PO 4 3- ) to a coastal lagoon (La Palme lagoon; France, Mediterranean Sea) using concurrent water and radon mass balances. The recirculation of lagoon water through sediments represents a source of NH 4 + (1900-5500 mol d -1 ) and PO 4 3- (22-71 mol d -1 ), but acts as a sink of NO 3 - . Estimated karstic groundwater-driven inputs of NO 3 - , NH 4 + and PO 4 3- to the lagoon are on the order of 200-1200, 1-12 and 1.5-8.7 mol d -1 , respectively. A comparison between the main nutrient sources to the lagoon (karstic groundwater, recirculation, diffusion from sediments, inputs from a sewage treatment plant and atmospheric deposition) reveals that the recirculation of lagoon water through sediments is the main source of both dissolved inorganic nitrogen (DIN) and phosphorous (DIP) to La Palme lagoon. These results are in contrast with several studies conducted in systems influenced by terrestrial groundwater inputs, where groundwater is often assumed to be the main pathway for dissolved inorganic nutrient loads. This work highlights the important role of lagoon water recirculation through permeable sediments as a major conveyor of dissolved nutrients to coastal lagoons and, thus, the need for a sound understanding of the recirculation-driven nutrient fluxes and their ecological implications to sustainably manage lagoonal ecosystems. Copyright © 2018. Published by Elsevier B.V.

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.

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

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

Taphonomy of coral reefs from Southern Lagoon of Belize

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 representativemore » 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.« less

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...

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)…

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

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...

Methane emissions from MBT landfills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heyer, K.-U., E-mail: heyer@ifas-hamburg.de; 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 atmore » 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

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.

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.

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.

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...

Nitrous oxide and methane emissions during storage of dewatered digested sewage sludge.

PubMed

Willén, Agnes; Rodhe, Lena; Pell, Mikael; Jönsson, Håkan

2016-12-15

This study investigated the effect on greenhouse gas emissions during storage of digested sewage sludge by using a cover during storage or applying sanitisation measures such as thermophilic digestion or ammonia addition. In a pilot-scale storage facility, nitrous oxide and methane emissions were measured on average twice monthly for a year, using a closed chamber technique. The thermophilically digested sewage sludge (TC) had the highest cumulative emissions of nitrous oxide (1.30% of initial total N) followed by mesophilically digested sewage sludge stored without a cover (M) (0.34%) and mesophilically digested sewage sludge stored with a cover (MC) (0.19%). The mesophilically digested sewage sludge sanitised with ammonia and stored with a cover (MAC) showed negligible cumulative emissions of nitrous oxide. Emissions of methane were much lower from TC and MAC than from M and MC. These results indicate that sanitisation by ammonia treatment eliminates the production of nitrous oxide and reduces methane emissions from stored sewage sludge, and that thermophilic digestion has the potential to reduce the production of methane during storage compared with mesophilic digestion. The results also indicate a tendency for lower emissions of nitrous oxide and higher emissions of methane from covered sewage sludge compared with non-covered. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Mercury Concentrations in Coastal Sediment from Younger Lagoon, Central California

NASA Astrophysics Data System (ADS)

Hohn, R. A.; Ganguli, P. M.; Swarzenski, P. W.; Richardson, C. M.; Merckling, J.; Johnson, C.; Flegal, A. R.

2013-12-01

Younger Lagoon Reserve, located in northern Monterey Bay, is one of the few relatively undisturbed wetlands that remain along the Central Coast of California. This lagoon system provides protected habitat for more than 100 bird species and for populations of fish, mammals, and invertebrates. Total mercury (HgT) concentrations in water within Younger Lagoon appear to vary with rainfall conditions and range from about 5-15 pM. These concentrations are similar to HgT in water from six nearby lagoon systems. However, Younger Lagoon contains elevated concentrations of dissolved organic carbon (~1 mM) and monomethylmercury (MMHg, ~1 pM) relative to our comparison lagoon sites (DOC < 0.5 mM and MMHg < 0.5 pM). We attribute Younger Lagoon's high DOC and MMHg to its restricted connection to the ocean and minor riverine contribution. Coastal lagoons in this region typically form at the mouth of streams. They behave as small estuaries during the wet season when surface water discharge keeps the mouth of the stream open to the ocean, and then transition into lagoons in the dry season when a sand berm develops and effectively cuts off surface water exchange. At Younger Lagoon, the sand berm remains intact throughout the year, breaching only during particularly high tides or intense rain events. Therefore, the lagoon's connection to nearshore seawater is primarily via surface water - groundwater interaction through the sand berm. Because Younger Lagoon is largely isolated from a surface water connection with the ocean, runoff from upgradient urban and agricultural land has an enhanced impact on water (and presumably sediment) quality. As a result, the lagoon is eutrophic and experiences annual algal blooms. Groundwater surveys suggest surface water, groundwater, and coastal seawater are hydraulically connected at Younger Lagoon, and mixing among these water masses appears to influence water geochemistry. To date, no chemical analyses have been conducted on sediment from Younger

The correlation of sedimentation processes and land use through remote sensing: The case study of the Jequia Lagoon, Alagoas, Brazil

NASA Astrophysics Data System (ADS)

Ferreira Gomes, Heliene

This study is focused on mapping the correlation between the land-cover change, sedimentation processes and the spectral radiance patterns along the Jequia estuary using field observations and reference information, laboratory spectral reflectance measurements and LANDSAT Thematic Mapper (TM) data. The Jequia estuary comprises the lagoon and its surrounding and a tidal channel to the Atlantic Ocean. It is inserted in Tertiary and Quaternary deposits covered mainly by sugar-cane crops and rare remains of the moist tropical forest. Bottom sediments along the lagoon were sampled and used to analyze their grain size distribution and mineral content by X-ray diffraction. Those samples were also used in an experiment where several sediment concentrations were simulated and their spectra's reflectance was determined. Silt is the predominating grain size within the lagoon. Quartz and kaolinite are the main minerals present within the silt and clay grain size fractions. Aerial photographs, satellite quick-look recorded in 1989 and a LANDSAT TM digital image recorded in 1990, were analyzed. The satellite data were analyzed through the photo-interpretation and quantitative approaches. Eight land-use units were mapped based on the aerial photographs and six land-use units were defined from the quick-look image. Despite the different scales within the data, we recognized that the most significant change in land-cover from 1968 to 1990 was the clearing of almost 100% of the moist tropical forest and its replacement by sugarcane crops. Overall, the digital results (0,48 to 0,82 mum) using standard classifiers indicate three water classes for the lagoon and ten land-use classes for the land surrounding the lagoon. The laboratory reflectance experimentation for suspended sediments demonstrates an overall increase of reflectance with increasing wavelength range for low and high concentrations. The reflectance for high sediment concentration shows a distinctive increase close to the

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

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 CH 4 oxidation potential and biological characteristics with CH 4 concentration was studied in a landfill cover soil reactor (LCSR). The maximum rate of CH 4 oxidation reached 32.40 mol d -1 m -2 by providing sufficient O 2 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 CH 4 and O 2 . The values of [Formula: see text] (0.93-2.29%) and [Formula: see text] (140-524 nmol kg soil-DW -1 ·s -1 ) increased with CH 4 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 CH 4 concentration. These findings provide information for assessing CH 4 oxidation potential and changing of biological characteristics in landfill cover soil.

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,…

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

Santa Margarita Lagoon Water Quality Monitoring Data

DTIC Science & Technology

2012-08-01

sits entirely within the boundaries of Marine Corps Base Camp Pendleton. It forms up where the Santa Margarita River meets the Pacific Ocean just north...of Oceanside, California. The western boundary of the lagoon is the beach berm that borders the ocean . The estuarine lagoon is usually open to the... ocean through a limited section of berm, although there are occasions when the lagoon is effectively closed to exchange with the ocean . The eastern

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

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

Methane Recovery from Animal Manures The Current Opportunities Casebook

DOE Office of Scientific and Technical Information (OSTI.GOV)

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-effectivemore » 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

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.

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.

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

Scottish saline lagoons: Impacts and challenges of climate change

NASA Astrophysics Data System (ADS)

Angus, Stewart

2017-11-01

The majority of Scotland's saline lagoons are located on the low-lying coastlines of the Western Isles and the northern archipelagos of Orkney and Shetland, where recorded annual relative sea level rise rates are among the highest in Scotland. The sediment-impounded lagoons of Orkney and Shetland will either lose their impoundment and become incorporated in marine coastal waters, or become increasingly saline, as relative sea levels rise. The rock-basin lagoons of the Western Isles will retain their restricted exchange with the sea but will also become more saline with rising sea level. Specialist lagoonal organisms tend to have wide salinity tolerances but may succumb to competition from marine counterparts. In all areas, there are sufficient fresh-water inland water bodies with potential to be captured as lagoons to compensate for loss of extent and number, but the specialist lagoon biota tend to have limited dispersal powers. It is thus possible that they will be unable to transfer to their analogue sites before existing lagoons become fully marine, giving conservation managers the problem of deciding on management options: leave natural processes to operate without interference, manage the saline inflow to maintain the current salinity regime, or translocate lagoon organisms perceived as threatened by rising salinities. Timing of conversion and capture is unpredictable due to local topography and complications caused by variable stratification.

The effect of lagoons on Adriatic Sea tidal dynamics

NASA Astrophysics Data System (ADS)

Ferrarin, Christian; Maicu, Francesco; Umgiesser, Georg

2017-11-01

In this study the effects that lagoons exert on the barotropic tidal dynamics of a regional sea, the Adriatic Sea, were numerically explored. This semi-enclosed basin is one of the places with the highest tidal range in the Mediterranean Sea and is characterised by the presence of several lagoons in its northern part. The tidal dynamics of a system comprising the whole Adriatic Sea and the lagoons of Venice, Marano-Grado and Po Delta were investigated using an unstructured hydrodynamic model. Numerical experiments with and without lagoons reveal that even if the considered shallow water bodies represent only the 0.5 and 0.002% of the Adriatic Sea surface and volume, respectively, they significantly affect the entire Northern Adriatic Sea tidal dynamics by enhancing tidal range (by 5%) and currents (by 10%). The inclusion of lagoons in the computation improved the model performance by 25% in reproducing tidal constituents in the Adriatic Sea. The back-effect of the lagoons on the open-sea tide is due to the waves radiating from the co-oscillating lagoons into the adjacent sea. This is the first time these processes are shown to be relevant for the Adriatic Sea, thus enhancing the understanding of the tidal dynamics in this regional sea. These findings may also apply to other coastal seas with connections to lagoons, bays and estuaries.

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

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

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 ...

Mapping methane emissions using the airborne imaging spectrometer AVIRIS-NG

NASA Astrophysics Data System (ADS)

Thorpe, A. K.; Frankenberg, C.; Thompson, D. R.; Duren, R. M.; Bue, B. D.; Green, R. O.

2017-12-01

The next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) has been used to survey large regions and map methane plumes with unambiguous identification of emission source locations. This capability is aided by real time detection and geolocation of gas plumes, permitting adaptive surveys and communication to ground teams for rapid follow up. We present results from AVIRIS-NG flight campaigns in Colorado, New Mexico, and California. Hundreds of plumes were observed, reflecting emissions from the energy sector that include hydraulic fracturing, gas processing plants, tanks, pumpjacks, and pipeline leaks. In some cases, plumes observed by AVIRIS-NG resulted in mitigation. Additional examples will be shown for methane from dairy lagoons, landfills, natural emissions, as well as carbon dioxide from power plants and refineries. We describe the unique capabilities of airborne imaging spectrometers to augment other measurement techniques by efficiently surveying key regions for methane point sources and supporting timely assessment and mitigation. We summarize the outlook for near- and longer-term monitoring capabilities including future satellite systems. Figure caption. AVIRIS-NG true color image subset with superimposed methane plume showing retrieved gas concentrations. Plume extends 200 m downwind of the southern edge of the well pad. Google Earth imagery with finer spatial resolution is also included (red box), indicating that tanks in the inset scene as the source of emissions. Five wells are located at the center of this well pad and all use horizontal drilling to produce mostly natural gas.

Benthic ecology of tropical coastal lagoons: Environmental changes over the last decades in the Términos Lagoon, Mexico

NASA Astrophysics Data System (ADS)

Grenz, Christian; Fichez, Renaud; Silva, Carlos Álvarez; Benítez, Laura Calva; Conan, Pascal; Esparza, Adolfo Contreras Ruiz; Denis, Lionel; Ruiz, Silvia Díaz; Douillet, Pascal; Martinez, Margarita E. Gallegos; Ghiglione, Jean-François; Mendieta, Francisco José Gutiérrez; Origel-Moreno, Montserrat; Garcia, Antonio Zoilo Marquez; Caravaca, Alain Muñoz; Pujo-Pay, Mireille; Alvarado, Rocío Torres; Zavala-Hidalgo, Jorge

2017-10-01

The Términos Lagoon is a 2000-km2 wide coastal lagoon linked to the largest river catchment in Mesoamerica. Economic development, together with its ecological importance, led the Mexican government to pronounce the Términos Lagoon and its surrounding wetlands as a Federal protected area for flora and fauna in 1994. It is characterized by small temperature fluctuations, but with two distinct seasons (wet and dry) that control the biological, geochemical, and physical processes and components. This paper presents a review of the available information about the Términos Lagoon. The review shows that the diversity of benthic communities is structured by the balance between marine and riverine inputs and that this structuration strongly influences the benthic metabolism and its coupling with the biogeochemistry of the water column. The paper also presents many specific drivers and recommendations for a long-term environmental survey strategy in the context of the expected Global Change in the Central American region.

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.

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 equal distribution in the inlet channel and the lagoon (56.3% and 43.7% respectively). The presence of species of the Mugilidae family (5.2% total average catches after lagoon re-flooding) was mainly in the inlet channel (12.6% of the average catches) and not inside the lagoon (only 1.3% of the average catches). The small number of fish species inhabiting the lagoon might be the result of the recent restoration or it could be related with the increased water flow observed at the lagoon mouth during the flood and ebb tidal phases, and also in the presence of a smooth bank in the concrete waterspout that connects the entrance channel with the lagoon. The limited presence of the Mugilidae juveniles inside the lagoon could be related to the prevailing tidal inlet dynamics (i.e. strong ebb flow at lagoon inlet), thus preventing the species to enter the lagoon. In order to restore the lagoon

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.

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.

Nutrient removal from swine lagoon effluent by duckweed

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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{submore » 4}-P, TOC, K, Cu, and Zn were 83, 100, 49, 31, 68, 21, 28 and 67%.« less

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.

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 ...

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.

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

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

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.

Long-term changes of fisheries landings in enclosed gulf lagoons (Amvrakikos gulf, W Greece): Influences of fishing and other human impacts

NASA Astrophysics Data System (ADS)

Katselis, George N.; Moutopoulos, Dimitrios K.; Dimitriou, Evagelos N.; Koutsikopoulos, Constantin

2013-10-01

The present study analyses long-term annual fishery landings time series (1980-2007) for species derived from six lagoons (covering about 70 km2) around an important European wetland, the fjord-like Amvrakikos gulf. Landing trends for most abundant species revealed that typical lagoon fish species-groups, such as Mugilidae (Mugil cephalus, Chelon labrosus, Liza saliens, Liza aurata and Liza ramada), eels (Anguilla anguilla) and Gobies (mainly Zosteriosessor ophiocephalus) had largely decreased, while the landings of Sparus aurata increased during the entire study period. These trends led to a significant change in species composition during recent years that might be attributed to large-scale climatic changes as well as serious anthropogenic impacts that degraded the water quality and altered the hydrology within the gulf and lagoons, the increase of fishing exploitation in Amvrakikos gulf, the expansion of aquaculture activities within the gulf, the application of new fishing management practices in lagoons, and the increase of fish-eating sea-bird populations. The findings are needed for the implementation of an efficient and integrated management tool for the study of coastal systems.

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)

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 ...

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.

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. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Is the Venice Lagoon Noisy? First Passive Listening Monitoring of the Venice Lagoon: Possible Effects on the Typical Fish Community.

PubMed

Bolgan, Marta; Picciulin, Marta; Codarin, Antonio; Fiorin, Riccardo; Zucchetta, Matteo; Malavasi, Stefano

2016-01-01

Three passive listening surveys have been carried out in two of the three Venice lagoon tide inlets and inside the Venice island. The spectral content and the intensity level of the underwater noise as well as the presence or absence of Sciaena umbra and the distribution of its different sound patterns have been investigated in all the recording sites. The passive listening proved to be successful in detecting S. umbra drumming sounds in both Venice lagoon tide inlets. Our results indicate that the spectral content and the level of underwater noise pollution in the Venice lagoon could affect fish acoustic communication.

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.

Anaerobic biodegradability of Category 2 animal by-products: methane potential and inoculum source.

PubMed

Pozdniakova, Tatiana A; Costa, José C; Santos, Ricardo J; Alves, M M; Boaventura, Rui A R

2012-11-01

Category 2 animal by-products that need to be sterilized with steam pressure according Regulation (EC) 1774/2002 are studied. In this work, 2 sets of experiments were performed in mesophilic conditions: (i) biomethane potential determination testing 0.5%, 2.0% and 5.0% total solids (TS), using sludge from the anaerobic digester of a wastewater treatment plant as inoculum; (ii) biodegradability tests at a constant TS concentration of 2.0% and different inoculum sources (digested sludge from a wastewater treatment plant; granular sludge from an upflow anaerobic sludge blanket reactor; leachate from a municipal solid waste landfill; and sludge from the slaughterhouse wastewater treatment anaerobic lagoon) to select the more adapted inoculum to the substrate in study. The higher specific methane production was of 317 mL CH(4)g(-1) VS(substrate) for 2.0% TS. The digested sludge from the wastewater treatment plant led to the lowest lag-phase period and higher methane potential rate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Template-Assisted Wet-Combustion Synthesis of Fibrous Nickel-Based Catalyst for Carbon Dioxide Methanation and Methane Steam Reforming.

PubMed

Aghayan, M; Potemkin, D I; Rubio-Marcos, F; Uskov, S I; Snytnikov, P V; Hussainova, I

2017-12-20

Efficient capture and recycling of CO 2 enable not only prevention of global warming but also the supply of useful low-carbon fuels. The catalytic conversion of CO 2 into an organic compound is a promising recycling approach which opens new concepts and opportunities for catalytic and industrial development. Here we report about template-assisted wet-combustion synthesis of a one-dimensional nickel-based catalyst for carbon dioxide methanation and methane steam reforming. Because of a high temperature achieved in a short time during reaction and a large amount of evolved gases, the wet-combustion synthesis yields homogeneously precipitated nanoparticles of NiO with average particle size of 4 nm on alumina nanofibers covered with a NiAl 2 O 4 nanolayer. The as-synthesized core-shell structured fibers exhibit outstanding activity in steam reforming of methane and sufficient activity in carbon dioxide methanation with 100% selectivity toward methane formation. The as-synthesized catalyst shows stable operation under the reaction conditions for at least 50 h.

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...

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

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.

Nitrogen and Winter Cover Crop Effects on Spring and Summer Nutrient Uptake

USDA-ARS?s Scientific Manuscript database

Fertilization of bermudagrass [Cynodon dactylon (L.) Pers.] with swine-lagoon effluent in summer, April to September, does not match the period of productivity of the winter annual cover crops, annual ryegrass (Lolium multiflorum L.), cereal rye (Secale cereale), and berseem clover (Trifolium alexan...

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.

Exceptional summer warming leads to contrasting outcomes for methane cycling in small Arctic lakes of Greenland

NASA Astrophysics Data System (ADS)

Cadieux, Sarah B.; White, Jeffrey R.; Pratt, Lisa M.

2017-02-01

In thermally stratified lakes, the greatest annual methane emissions typically occur during thermal overturn events. In July of 2012, Greenland experienced significant warming that resulted in substantial melting of the Greenland Ice Sheet and enhanced runoff events. This unusual climate phenomenon provided an opportunity to examine the effects of short-term natural heating on lake thermal structure and methane dynamics and compare these observations with those from the following year, when temperatures were normal. Here, we focus on methane concentrations within the water column of five adjacent small lakes on the ice-free margin of southwestern Greenland under open-water and ice-covered conditions from 2012-2014. Enhanced warming of the epilimnion in the lakes under open-water conditions in 2012 led to strong thermal stability and the development of anoxic hypolimnia in each of the lakes. As a result, during open-water conditions, mean dissolved methane concentrations in the water column were significantly (p < 0.0001) greater in 2012 than in 2013. In all of the lakes, mean methane concentrations under ice-covered conditions were significantly (p < 0.0001) greater than under open-water conditions, suggesting spring overturn is currently the largest annual methane flux to the atmosphere. As the climate continues to warm, shorter ice cover durations are expected, which may reduce the winter inventory of methane and lead to a decrease in total methane flux during ice melt. Under open-water conditions, greater heat income and warming of lake surface waters will lead to increased thermal stratification and hypolimnetic anoxia, which will consequently result in increased water column inventories of methane. This stored methane will be susceptible to emissions during fall overturn, which may result in a shift in greatest annual efflux of methane from spring melt to fall overturn. The results of this study suggest that interannual variation in ground-level air

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 �

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 �

Initial crop growth in soil collected from a closed animal waste lagoon.

PubMed

Zhu, L; Kirkham, M B

2003-03-01

In the 21st century, remediation of the soil beneath animal waste lagoons will become an important issue, as they are closed due to environmental regulations or to abandonment. The possibility of growing crops in the soil, which has high concentrations of ammonium-N, has not been studied. The objective of this experiment was to determine if crop species would germinate and grow in lagoon soil. Soil was gathered from a lagoon that had received wastes from swine (Sus scrofa) and beef (Bos taurus) since 1968. Eight crops were grown in greenhouse pots containing the lagoon soil: winter barley (Hordeum vulgare L. 'Weskan'); field corn (Zea mays L., Cargill's hybrid 7997); 'Plainsman' winter rapeseed [Brassica napus L. spp. oleifera (Metzg.) Sinsk. f. biennis]; soybean [Glycine max (L.) Merr. 'KS 4694'); forage sorghum [Sorghum bicolor (L.) Moench 'Norkan']; sunflower (Helianthus annuus L. 'Hysun 354'); and winter wheat (Triticum aestivum L.)--two cultivars: '2137' and 'Turkey.' Plants were grown for 35 days in lagoon soil or an agricultural soil (Haynie very fine sandy loam; coarse-silty, mixed, superactive, calcareous, mesic Mollic Udifluvent) obtained from a field near the closed lagoon. Ammonium-N (average value of 692 mg/kg) was about 70-85 times greater than the average value of 8-10 mg/kg NH4-N in Kansan soils. The lagoon soil was nonsodic and had a salinity ranking of "medium" with an electrical conductivity averaging 2.29 dS/m. The high ammonium-N concentration in the lagoon soil was not inhibitory to emergence and growth. The eight crops grew taller in the lagoon soil than in the agricultural soil. Except for '2137' wheat, dry weight was higher in the lagoon soil than in the agricultural soil. The results showed that the lagoon soil is not detrimental to early growth of eight crops.

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

The occurrence and distribution of high-arsenic, selenium, tin and antimony in bottom sediments of Burullus lagoon and its effects on human health, Egypt

NASA Astrophysics Data System (ADS)

El-Badry, Abd El-Monsef Ahmed; Khalifa, Moataz M.

2017-12-01

Burullus lagoon is one of four natural water bodies known as northern Egyptian delta lakes. The lagoon extended maximum long of 53 km long and maximum width 13 km with an area about 420 km2. The pollution of bottom sediment of the Burullus lagoon is indicative of both water and food web quality in general. A few research were carried out related to study of arsenic, selenium, tin and antimony. The main objective of this study is assessment of environmental effects of arsenic, selenium, tin and antimony metals, twenty-one samples were collect from bottom sediments sample among sites covering the Burullus Lagoon during summer 2014, and analyzed by using simultaneous inductively coupled plasma emission spectrometer. The contamination with these metals was evaluate by applying index of contamination factor (CF) and geoaccumulation (Igeo). The relative order of abundance of the potentially toxic metals in the lagoon's sediment is Se > Sn > Sb > As The territory around inlet and southeastern drain show considerable pollution by the studied toxic metals. The main reason for such pollution resulting from industrial activities and agricultural drains. The disregards of the anthropogenic activities are the main reason of pollution in the studied lagoon. Construction of special units for treatment and purification of all types of drainage and wastewater (agricultural, industrial). Successive analysis of lake water to assess the amount of pollutants to make suitable decisions. Take an action to prohibit throwing of wastes in the lagoon. Consumption of the lake water for agricultural and industrial must be under control in order to decrease water pollution.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Widory, D., E-mail: d.widory@brgm.fr; Proust, E.; Bellenfant, G.

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 amore » 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.« less

Overview of ecotoxicological studies performed in the Venice Lagoon (Italy).

PubMed

Losso, C; Ghirardini, A Volpi

2010-01-01

This work reports on the state of the art of the bioindicators used to assess environmental quality (regarding chemical pollutant impacts) in the Venice lagoon. After a brief description of the roles, advantages and limitations of bioindicators in marine and transitional environments and a summary of the Venice lagoon characteristics, the ecotoxicological methods used during scientific studies and research projects in the Lagoon are reported. Since not all data are available and no database can be formulated, the main evidence from toxicity bioassays, biomarkers and bioaccumulation analyses since the end of the 1970s is spatially synthesized using maps and discussed according to the four Venice lagoon basins. The majority of indicators showed that the Lido basin (north-central lagoon), affected by the presence of the industrial area and the city of Venice, is the one most highly impacted (particularly in the sites located within or in front of the industrial area, which showed very high sediment toxicity and high levels of DNA damage). The Malamocco basin (south-central lagoon) seems to be the least problematic. The southern basin (Chioggia basin) was shown to be impacted by urban contaminants from the town of Chioggia. The northern basin (Treporti basin) presented both impacted sites (high toxicity and high bioaccumulation factor) and relatively unpolluted sites (absence of toxicity, absence of imposex and low levels of bioaccumulation). This review can serve as a basis on which to select pragmatic, cost-effective biomonitoring techniques for environmental effects in lagoon ecosystems.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sfriso, A.; Pavoni, B.; Marcomini, 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 primarymore » 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.« less

Metagenomic Survey of a Military-Impacted Lagoon in Puerto Rico

NASA Astrophysics Data System (ADS)

Davila-Santiago, L.; DeLeon-Rodriguez, N.; LaSanta-Pagan, K. Y.; Kurt, Z.; Padilla-Crespo, E.; Hatt, J.; Spain, J.; Konstantinidis, K.; Massol-Deya, A.

2016-02-01

Military practices have left a legacy of contamination worldwide. In Puerto Rico, the east part of the populated Vieques Island was used for over fifty years as a bombing range by the Navy. A year after the base was closed in 2003, the impacted area was designated as a Superfund site. Previous studies have shown elevated levels of heavy metals, explosives (e.g. RDX, TNT, HMX), and other toxic chemicals at the site. The Anones Lagoon, located in the middle of the bombing range is one of the most polluted spots within the site. Intermittently, the lagoon is connected through a channel to the Caribbean Sea. In order to describe the microbial diversity and its potential contribution to natural attenuation of explosives, sediment samples have been collected since 2005. Sediment from reference lagoons (San Juan and Cabo Rojo) have also been sampled and analyzed in parallel for comparisons. Total DNA was extracted and sequenced using Ilumina My-Seq platform. Results indicate that Gammaproteobacteria were abundant in all lagoons samples but the Vieques lagoon harbors overall different microbial taxa. Alpha diversity analysis showed that Anones was less diverse compared to the pristine Cabo Rojo lagoon. Importantly, a clear shift was seen in the Anones Lagoon in 2013 compared to 2005, were Halomonas spp. became dominant (up to 25%) while other groups like Marinobacter showed signs of enrichment as well. Interestingly, these groups have been shown to degrade explosive-related chemicals in tropical sediments. Functional gene annotation of the Anones metagenome showed the presence of RDX degradation genes such as cytochrome p450. This study is the first comparative metagenomic survey of lagoons in Puerto Rico that explored the microbial diversity and biodegradation potential at Vieques.

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…

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toxic metals in Venics lagoon sediments: Model, observation, an possible removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basu, A.; Molinaroli, E.

1994-11-01

We have modeled the distribution of nine toxic metals in the surface sediments from 163 stations in the Venice lagoon using published data. Three entrances from the Adriatic Sea control the circulation in the lagoon and divide it into three basins. We assume, for purposes of modeling, that Porto Marghera at the head of the Industrial Zone area is the single source of toxic metals in the Venice lagoon. In a standing body of lagoon water, concentration of pollutants at distance x from the source (C{sub 0}) may be given by C=C{sub 0}e{sup -kx} where k is the rate constantmore » of dispersal. We calculated k empirically using concentrations at the source, and those farthest from it, that is the end points of the lagoon. Average k values (ppm/km) in the lagoon are: Zn 0.165, Cd 0.116, Hg 0.110, Cu 0.105, Co 0.072, Pb 0.058, Ni 0.008, Cr (0.011) and Fe (0.018 percent/km), and they have complex distributions. Given the k values, concentration at source (C{sub 0}), and the distance x of any point in the lagoon from the source, we have calculated the model concentrations of the nine metals at each sampling station. Tides, currents, floor morphology, additional sources, and continued dumping perturb model distributions causing anomalies (observed minus model concentrations). Positive anomalies are found near the source, where continued dumping perturbs initial boundary conditions, and in areas of sluggish circulation. Negative anomalies are found in areas with strong currents that may flush sediments out of the lagoon. We have thus identified areas in the lagoon where higher rate of sediment removal and exchange may lesson pollution. 41 refs., 4 figs., 3 tabs.« less

First steps of ecological restoration in Mediterranean lagoons: Shifts in phytoplankton communities

NASA Astrophysics Data System (ADS)

Leruste, A.; Malet, N.; Munaron, D.; Derolez, V.; Hatey, E.; Collos, Y.; De Wit, R.; Bec, B.

2016-10-01

Along the French Mediterranean coast, a complex of eight lagoons underwent intensive eutrophication over four decades, mainly related to nutrient over-enrichment from continuous sewage discharges. The lagoon complex displayed a wide trophic gradient from mesotrophy to hypertrophy and primary production was dominated by phytoplankton communities. In 2005, the implementation of an 11 km offshore outfall system diverted the treated sewage effluents leading to a drastic reduction of anthropogenic inputs of nitrogen and phosphorus into the lagoons. Time series data have been examined from 2000 to 2013 for physical, chemical and biological (phytoplankton) variables of the water column during the summer period. Since 2006, total nitrogen and phosphorus concentrations as well as chlorophyll biomass strongly decreased revealing an improvement in lagoon water quality. In summertime, the decline in phytoplankton biomass was accompanied by shifts in community structure and composition that could be explained by adopting a functional approach by considering the common functional traits of the main algal groups. These phytoplankton communities were dominated by functional groups of small-sized and fast-growing algae (diatoms, cryptophytes and green algae). The trajectories of summer phytoplankton communities displayed a complex response to changing nutrient loads over time. While diatoms were the major group in 2006 in all the lagoons, the summer phytoplankton composition in hypertrophic lagoons has shifted towards green algae, which are particularly well adapted to summertime conditions. All lagoons showed increasing proportion and occurrence of peridinin-rich dinophytes over time, probably related to their capacity for mixotrophy. The diversity patterns were marked by a strong variability in eutrophic and hypertrophic lagoons whereas phytoplankton community structure reached the highest diversity and stability in mesotrophic lagoons. We observe that during the re

Reducing Open Cell Landfill Methane Emissions with a Bioactive Alternative Daily

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helene Hilger; James Oliver; Jean Bogner

2009-03-31

Methane and carbon dioxide are formed in landfills as wastes degrade. Molecule-for-molecule, methane is about 20 times more potent than carbon dioxide at trapping heat in the earth's atmosphere, and thus, it is the methane emissions from landfills that are scrutinized. For example, if emissions composed of 60% methane and 40% carbon dioxide were changed to a mix that was 40% methane and 60% carbon dioxide, a 30% reduction in the landfill's global warming potential would result. A 10% methane, 90% carbon dioxide ratio will result in a 75% reduction in global warming potential compared to the baseline. Gas collectionmore » from a closed landfill can reduce emissions, and it is sometimes combined with a biocover, an engineered system where methane oxidizing bacteria living in a medium such as compost, convert landfill methane to carbon dioxide and water. Although methane oxidizing bacteria merely convert one greenhouse gas (methane) to another (carbon dioxide), this conversion can offer significant reductions in the overall greenhouse gas contribution, or global warming potential, associated with the landfill. What has not been addressed to date is the fact that methane can also escape from a landfill when the active cell is being filled with waste. Federal regulations require that newly deposited solid waste to be covered daily with a 6 in layer of soil or an alternative daily cover (ADC), such as a canvas tarp. The aim of this study was to assess the feasibility of immobilizing methane oxidizing bacteria into a tarp-like matrix that could be used for alternative daily cover at open landfill cells to prevent methane emissions. A unique method of isolating methanotrophs from landfill cover soil was used to create a liquid culture of mixed methanotrophs. A variety of prospective immobilization techniques were used to affix the bacteria in a tarp-like matrix. Both gel encapsulation of methanotrophs and gels with liquid cores containing methanotrophs were readily made

DESIGN INFORMATION REPORT: PROTECTION OF WASTEWATER LAGOON INTERIOR SLOPES

EPA Science Inventory

A problem common to many wastewater treatment and storage lagoons is erosion of the interior slopes. Erosion may be caused by surface runoff and wind-induced wave action. The soils that compose the steep interior slopes of lagoons are especially susceptible to erosion and slumpin...

Coastal Processes with Improved Tidal Opening in Chilika Lagoon (east Coast of India)

NASA Astrophysics Data System (ADS)

Jayaraman, Girija; Dube, Anumeha

Chilika Lagoon (19°28-19°54¢N and 85°06-85°36¢E) is the largest brackish water lagoon with estuarine character. Interest in detailed analysis of the ecology of the lagoon and the various factors affecting it is due to the opening of the new mouth on September 23, 2000 to resolve the threat to its environment from various factors - Eutrophication, weed proliferation, siltation, industrial pollution, and depletion of bioresources. The opening of the new mouth has changed the lagoon environment significantly with better socio­economic implications. There is a serious concern if the significant improvement in the biological productivity of the lagoon post-mouth opening is indeed sustainable. The present study focuses on the changes in the coastal processes as a result of the additional opening of a new mouth. Our results based on mathematical modeling and numerical simulation compare the dynamics, nutrient, and plankton distribution before and after the new mouth opening. The model could confirm the significant increase (14-66% depending on the sector) in the salinity after the new mouth opening, the maximum change being observed in the channel which connects the lagoon to the sea. The constriction in the lagoon which blocks the tidal effects entering the lagoon must be responsible for maintaining the main body of the lagoon with low salinity. The ecological model is first tested for different sectors individually before a complete model, including the entire lagoon area, is included incorporating their distinct characteristics. The model is validated with available observations of plankton and nutrients made before the opening of the new mouth. It predicts the annual distribution of plankton in all the sectors of the lagoon for post-mouth opening which is to be verified when the data will be forthcoming.

Coastal Processes with Improved Tidal Opening in Chilika Lagoon (east Coast of India)

NASA Astrophysics Data System (ADS)

Jayaraman, Girija; Dube, Anumeha

Chilika Lagoon (19°28-19°54'N and 85°06-85°36'E) is the largest brackish water lagoon with estuarine character. Interest in detailed analysis of the ecology of the lagoon and the various factors affecting it is due to the opening of the new mouth on September 23, 2000 to resolve the threat to its environment from various factors — Eutrophication, weed proliferation, siltation, industrial pollution, and depletion of bioresources. The opening of the new mouth has changed the lagoon environment significantly with better socio-economic implications. There is a serious concern if the significant improvement in the biological productivity of the lagoon post-mouth opening is indeed sustainable. The present study focuses on the changes in the coastal processes as a result of the additional opening of a new mouth. Our results based on mathematical modeling and numerical simulation compare the dynamics, nutrient, and plankton distribution before and after the new mouth opening. The model could confirm the significant increase (14-66% depending on the sector) in the salinity after the new mouth opening, the maximum change being observed in the channel which connects the lagoon to the sea. The constriction in the lagoon which blocks the tidal effects entering the lagoon must be responsible for maintaining the main body of the lagoon with low salinity. The ecological model is first tested for different sectors individually before a complete model, including the entire lagoon area, is included incorporating their distinct characteristics. The model is validated with available observations of plankton and nutrients made before the opening of the new mouth. It predicts the annual distribution of plankton in all the sectors of the lagoon for post-mouth opening which is to be verified when the data will be forthcoming.

Chemistry of modern sediments in a hypersaline lagoon, north of Jeddah, Red Sea

NASA Astrophysics Data System (ADS)

El-Sayed, Mahmoud Kh.

1987-10-01

Previous studies of modern peritidal sedimentary environments of the Red Sea, such as hypersaline lagoons and sea-marginal flats, have concentrated on its northern part, particularly in the Gulf of Aqaba. However, little is known about lagoon sediments in other localities along the Red Sea coastal stretches. This paper deals with the chemical characteristics of the sediments of a hypersaline (Ras Hatiba) lagoon, north of Jeddah, Saudi Arabia. The chemistry of hypersaline lagoon sediments is considerably changed following the modifications to the water chemistry by evaporation and precipitation. Ras Hatiba lagoon is a hypersaline elongated water body connected to the Red Sea by a narrow and shallow opening. The total area of the lagoon is c. 30 km 2. Coarse bioclastic sands are dominant in the lagoon and mostly surround lithified calcareous grounds. However, fine silt and clay sediments are present in separate patches. The sediments are rich in carbonates (average 78·5%) and organic carbon (average 7·3%), although they are negatively correlated. Calcium (average 25·1%) and magnesium (average 10·8‰) show a similar distribution pattern in the lagoon sediments. Strontium (average 5·2‰) is positively correlated with calcium. Sodium and potassium are relatively highly concentrated in the sediments (average 118 ppm and 173 ppm, respectively). Magnesium and strontium are of prime importance in the process of mineralization and diagenesis. The sabkha formation surrounding the lagoon is of low carbonate and organic carbon content, compared with the lagoon sediments, whilst it is characterized by high magnesium, sodium and potassium concentrations. Ras Hatiba lagoon sediments and sabkha resemble those of the northern Red Sea in the Gulfs of Aqaba and Suez and the Arabian Gulf in their major sedimentological and chemical characteristics.

The distribution of salinity and main forcing effects in the Berre lagoon

NASA Astrophysics Data System (ADS)

Roux, Bernard; Alekseenko, Elena; Chen, Paul Gang; Kharif, Christian; Kotarba, Richard; Fougere, Dominique

2014-05-01

The results from previous studies in lagoons and well mixed estuaries indicate that salt transport is primarily in response to advection associated with freshwater outflow, tidal diffusion, and to shear effects arising from spatial correlations of vertical and especially transverse deviations in salinity and current speed (Smith, 1994). Therefore, the inflow of fresh and salt water into coastal lagoons is an important factor influencing the structure and function of lagoonal ecosystems worldwide (Lirman et al., 2007). The predominance of marine or freshwater inflow leads to the different ecosystems. Among several lagoons located along the Mediterranean shore of France, the Berre lagoon has been under intense anthropogenic pressure for several decades (Delpy et al., 2012). Moreover, the salinity level of the Berre lagoon was varying dramatically from the 19th century up to now. In this work, a special attention is focused on the salinity variation in the Berre lagoon due to the three dominant abiotic forcing mechanisms, i.e., incoming sea tide, runoff from a hydropower and a strong wind. Four different model scenarios were considered in order to examine the impact of each forcing mechanism or combined effects, i.e. : (a) tide only, (b) runoff only, (c) combined tide and runoff, and (d) an N-NW wind, tide and runoff together. Numerical modeling and interpretation of numerical results are based on three-dimensional hydrodynamic model MARS3D. It is found that the strongest negative impact is related to the huge hydropower runoffs, inducing the desalinization of the surface and subsurface waters not only in the centre of the lagoon, but also in the entire water column in the coastal seagrass recolonization zones. In the absence of wind, the huge inputs of freshwater from the hydropower lead to a haline stratification and thus, to anoxic conditions, making most of the lagoon unproductive. On the contrary, strong winds play a positive role on the salinity level of the

Coal-bed methane potential in Montana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campen, E.

1991-06-01

Montana's coal resources are the second largest of the US, with coal underlying approximately 35% of the state. These resources are estimated at 478 billion tons. Associated coal-bed methane resources are estimated to be 14 tcf. The coals of Montana range from Jurassic to early Tertiary in age and from lignite to low-volatile bituminous in rank. Thickness, rank, maceral composition, and proximate and ultimate analyses all vary vertically and laterally. The state contains eight major coal resource areas. A large percentage of Montana's coal consists of the Paleocene Fort Union lignites of eastern Montana, generally considered of too low amore » rank to contain significant methane resources. Most of the state's other coal deposits are higher in rank and contain many recorded methane shows. During Cretaceous and Tertiary times, regressive-transgressive cycles resulted in numerous coal-bearing sequences. Major marine regressions allowed the formation of large peat swamps followed by transgressions which covered the swamps with impervious marine shales, preventing the already forming methane from escaping. About 75% of Montana's coal is less than 1,000 ft below the ground's surface, making it ideal for methane production. Associated water appears to be fresh, eliminating environmental problems. Pipelines are near to most of the major coal deposits. Exploration for coal-bed methane in Montana is still in its infancy but at this time shows commercial promise.« less

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.

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

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...

Seasonal Variability in Mercury Speciation within Select Coastal Lagoons of Central California

NASA Astrophysics Data System (ADS)

Ganguli, P. M.; Conaway, C. H.; Dimova, N. T.; Swarzenski, P. W.; Kehrlein, N. C.; Flegal, A. R.

2011-12-01

Coastal lagoons may play an important role in mercury biogeochemical cycling at the land-sea margin. Along the coast of California, these systems are seasonally dynamic, behaving as estuaries during the wet season and as lagoons in the dry season when ephemeral sand berms develop and isolate terrestrial freshwater from direct exchange with the ocean. As a consequence, many lagoons become eutrophic in the dry season and are characterized by high nutrient and low dissolved oxygen concentrations. Because monomethylmercury (MMHg) production can be mediated by anaerobic bacteria, coastal lagoons are a potential source of biologically available MMHg that may be transported to the nearshore environment via submarine groundwater discharge. To evaluate the importance of coastal lagoons at the land-sea margin, we quantified total mercury (HgT) and MMHg concentrations in surface water and coastal seawater from six sites during dry and wet season conditions, including one storm event. Additionally, we conducted a tidal study at one lagoon in which we sampled surface water, seawater, and groundwater over a 10-hour period during a falling tide (+1.63 to 0.00 m). Groundwater was collected using a multi-port piezometer screened at depths ranging from 1 m to a few centimeters below the lagoon's sediment-water interface. This enabled us to characterize surface water - groundwater interaction. During wet season conditions, the average unfiltered HgT (U-HgT) concentration in surface water at the tidal study lagoon was 13 pM and did not fluctuate in response to tidal changes. Filtered (< 0.45 μm) HgT (F-HgT) concentrations in the lagoon were similar to U-HgT concentrations during high tide and decreased to 8 pM during low tide. Groundwater F-HgT concentrations were about 1.5 pM at a depth of 1 m and systematically increased at shallower depths, reaching approximately 6 pM near the surface. These data indicate F-HgT exchange between the lagoon and groundwater to a depth of at least 1 m

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.

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

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.

Redistribution of fallout radionuclides in Enewetak Atoll lagoon sediments by callianassid bioturbation.

PubMed

McMurtry, G M; Schneider, R C; Colin, P L; Buddemeier, R W; Suchanek, T H

The lagoon sediments of Enewetak Atoll in the Marshall Islands contain a large selection of fallout radionuclides as a result of 43 nuclear weapon tests conducted there between 1948 and 1958. Studies of the burial of fallout radionuclides have been conducted on the islands and in several of the large craters, but studies of their vertical distribution have been limited to about the upper 20 cm of the lagoon sediments. We have found elevated fallout radionuclide concentrations buried more deeply in the lagoon sediments and evidence of burrowing into the sediment by several species of callianassid ghost shrimp (Crustacea: Thalassinidea) which has displaced highly radioactive sediment. The burrowing activities of callianassids, which are ubiquitous on the lagoon floor, facilitate radionuclide redistribution and complicate the fallout radionuclide inventory of the lagoon.

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.

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

Comparison of the seasonal variability in abundance of the copepod Pseudocalanus newmani in Lagoon Notoro-ko and a coastal area of the southwestern Okhotsk Sea

NASA Astrophysics Data System (ADS)

Kitamura, Mitsuaki; Nakagawa, Yoshizumi; Nishino, Yasuto; Segawa, Susumu; Shiomoto, Akihiro

2018-03-01

Replacement of the warm water of the Soya Warm Current (SWC) and the cold water of the East Sakhalin Current (ESC) occurs seasonally along the coast of the southwestern Okhotsk Sea, and sea ice covers the surface during winter. Pseudocalanus newmani is one of the dominant copepods in coastal waters of the northern hemisphere. To better understand the population dynamics of the copepod P. newmani in coastal areas of the southwestern Okhotsk Sea, this study compared the seasonal variation in P. newmani abundance in Lagoon Notoro-ko and a coastal area of the Okhotsk Sea with regard to developmental stage. We sampled P. newmani in the lagoon, including during the ice cover season, and the coastal waters. Pseudocalanus newmani was abundant at both sites in spring. During summer-fall, adults disappeared from the populations at both sites, whereas the early developmental stages were abundant and dominated the population. Total length of adult females decreased toward summer at both sites. Pseudocalanus newmani abundance in the lagoon increased in early winter, and larger females were found in the populations at both sites. These phenomena at both sites corresponded with seasonal variation in water temperature caused by seasonal water-mass replacement and sea ice.

Mechanism of nitrogen removal in wastewater lagoon: a case study.

PubMed

Vendramelli, Richard A; Vijay, Saloni; Yuan, Qiuyan

2017-06-01

Ammonia being a nutrient facilitates the growth of algae in wastewater and causes eutrophication. Nitrate poses health risk if it is present in drinking water. Hence, nitrogen removal from wastewater is required. Lagoon wastewater treatment systems have become common in Canada these days. The study was conducted to understand the nitrogen removal mechanisms from the existing wastewater treatment lagoon system in the town of Lorette, Manitoba. The lagoon system consists of two primary aerated cells and two secondary unaerated cells. Surface samples were collected periodically from lagoon cells and analysed from 5 May 2015 to 9 November 2015. The windward and leeward sides of the ponds were sampled and the results were averaged. It was found that the free ammonia volatilization to the atmosphere is responsible for most of the ammonia removal. Ammonia and nitrate assimilation into biomass and biological growth in the cells appears to be the other mechanisms of nitrogen removal over the monitoring period. Factors affecting the nitrogen removal efficiency were found to be pH, temperature and hydraulic residence time. Also, the ammonia concentration in the effluent from the wastewater treatment lagoon was compared with the regulatory standard.

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.

Environmental quality of transitional waters: the lagoon of Venice case study.

PubMed

Micheletti, C; Gottardo, S; Critto, A; Chiarato, S; Marcomini, A

2011-01-01

The health status of European aquatic environments, including transitional waters such as coastal lagoons, is regulated by the Water Framework Directive (WFD), which requires the classification of the water bodies' environmental quality and the achievement of a good ecological status by 2015. In the Venice lagoon, a transitional water body located in the northeastern part of Italy, the achievement of a good ecological status is hampered by several anthropogenic and natural pressures, such as sediment and water chemical contamination, and sediment erosion. In order to evaluate the lagoon's environmental quality according to the WFD (i.e. 5 quality classes, from High to Bad), an integrated Weight-of-Evidence methodology was developed and applied to classify the quality of the lagoon water bodies, integrating biological, physico-chemical, chemical, ecotoxicological, and hydromorphological data (i.e. Lines of Evidence, LOE). The quality assessment was carried out in two lagoon habitat typologies (previously defined on the basis of morphological, sediment, and hydrodynamic characteristics) which were selected taking into account the ecological gradient from sea to land, and the differences in anthropogenic pressure and contamination levels. The LOE classification was carried out by using indicators scored by comparing site specific conditions to reference conditions measured in lagoon reference sites, or provided by local, national or European regulations (e.g. Environmental Quality Standards, EQS, for chemicals). Finally, the overall quality status for each water body was calculated by a probabilistic approach, i.e. by reporting the final result as the frequency distribution of quality classes. The developed procedure was applied by using data and information concerning selected LOE and collected from monitoring programs and research studies carried out in the last 15 years in the lagoon of Venice. A set of sampling stations characterized by spatially and temporally

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.

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.

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.

Dynamics of copper and zinc sedimentation in a lagooning system receiving landfill leachate.

PubMed

Guigue, Julien; Mathieu, Olivier; Lévêque, Jean; Denimal, Sophie; Steinmann, Marc; Milloux, Marie-Jeanne; Grisey, Hervé

2013-11-01

This study characterises the sediment dredged from a lagooning system composed of a settling pond and three lagoons that receive leachates from a municipal solid waste (MSW) landfill in France. Organic carbon, carbonate, iron oxyhydroxides, copper (Cu) and zinc (Zn) concentrations were measured in the sediment collected from upstream to downstream in the lagooning system. In order to complete our investigation of sedimentation mechanisms, leachates were sampled in both dry (spring) and wet (winter) seasonal conditions. Precipitation of calcite and amorphous Fe-oxyhydroxides and sedimentation of organic matter occurred in the settling pond. Since different distributions of Zn and Cu concentrations are measured in sediment samples collected downstream in the lagooning system, it is suggested that these elements were not distributed in a similar way in the leachate fractions during the first stage of treatment in the settling pond, so that their sedimentation dynamics in the lagooning system differ. In the lagoons, it was found that organic carbon plays a major role in Cu and Zn mobility and trapping. The presence of macrophytes along the edges provided an input of organic matter that enhanced Cu and Zn scavenging. This edge effect resulted in a two-fold increase in Cu and Zn concentrations in the sediment deposited near the banks of the lagoons, thus confirming the importance of vegetation for the retention of Cu and Zn in lagooning systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Temporal stability of otolith elemental fingerprints discriminates among lagoon nursery habitats

NASA Astrophysics Data System (ADS)

Tournois, Jennifer; Ferraton, Franck; Velez, Laure; McKenzie, David J.; Aliaume, Catherine; Mercier, Lény; Darnaude, Audrey M.

2013-10-01

The chemical composition of fish otoliths reflects that of the water masses that they inhabit. Otolith elemental compositions can, therefore, be used as natural tags to discriminate among habitats. However, for retrospective habitat identification to be valid and reliable for any adult, irrespective of its age, significant differences in environmental conditions, and therefore otolith signatures, must be temporally stable within each habitat, otherwise connectivity studies have to be carried out by matching year-classes to the corresponding annual fingerprints. This study investigated how various different combinations of chemical elements in otoliths could distinguish, over three separate years, between four coastal lagoon habitats used annually as nurseries by gilthead sea bream (Sparus aurata L.) in the Gulf of Lions (NW Mediterranean). A series of nine elements were measured in otoliths of 301 S. aurata juveniles collected in the four lagoons in 2008, 2010 and 2011. Percentages of correct re-assignment of juveniles to their lagoon of origin were calculated with the Random Forest classification method, considering every possible combination of elements. This revealed both spatial and temporal variations in accuracy of habitat identification, with correct re-assignment to each lagoon ranging from 44 to 99% depending on the year and the lagoon. There were also annual differences in the combination of elements that provided the best discrimination among the lagoons. Despite this, when the data from the three years were pooled, a combination of eight elements (B, Ba, Cu, Li, Mg, Rb, Sr and Y) provided greater than 70% correct re-assignment to each single lagoon, with a multi-annual global accuracy of 79%. When considering the years separately, discrimination accuracy with these elemental fingerprints was above 90% for 2008 and 2010. It decreased to 61% in 2011, when unusually heavy rainfall occurred, which presumably reduced chemical differences among several of the

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

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

Low Permafrost Methane Emissions from Arctic Airborne Flux Measurements

NASA Astrophysics Data System (ADS)

Sachs, T.; Serafimovich, A.; Metzger, S.; Kohnert, K.; Hartmann, J.

2014-12-01

One of the most pressing questions with regard to climate feedback processes in a warming Arctic is the regional-scale greenhouse gas release from Arctic permafrost areas. Ground-based eddy covariance (EC) measurements provide continuous in-situ observations of the surface-atmosphere exchange of energy and matter. 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. The Airborne Measurements of Methane Fluxes (AIRMETH) campaigns are designed to quantitatively and spatially explicitly address this question. During the AIRMETH-2012 and AIRMETH-2013 campaigns aboard the research aircraft POLAR 5 we measured turbulent exchange of energy, methane, and (in 2013) carbon dioxide along thousands of kilometers covering the North Slope of Alaska and the Mackenzie Delta, Canada. Time-frequency (wavelet) analysis, footprint modeling, and machine learning techniques are used to (i) determine spatially resolved turbulence statistics, fluxes, and contributions of biophysical surface properties, and (ii) extract regionally valid functional relationships between environmental drivers and the observed fluxes. These environmental response functions (ERF) are used to explain spatial flux patterns and - if drivers are available in temporal resolution - allow for spatio-temporal scaling of the observations. This presentation will focus on 2012 methane fluxes on the North Slope of Alaska and the relevant processes on the regional scale and provide an updated 100 m resolution methane flux map of the North Slope of Alaska.

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.

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

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.

Copper complexation capacity in surface waters of the Venice Lagoon.

PubMed

Delgadillo-Hinojosa, Francisco; Zirino, Alberto; Nasci, Cristina

2008-10-01

Total copper (Cu(T)), copper ion activity (pCu) and the copper complexation capacity (CuCC) were determined in samples of seawater collected in July 2003 from the Venice Lagoon. Cu(T) and CuCC showed considerable spatial variability: Cu(T) ranged from 1.8 to 70.0nM, whereas the CuCC varied from 195 to 573nM. pCu values varied from 11.6 to 12.6 and are consistent with those previously reported in estuarine and coastal areas (10.9-14.1). The range of Cu(T) values compares well with those reported in the past in the lagoon and in the adjacent Adriatic Sea. The highest concentrations of Cu(T) were found in samples collected near the industrial area of Porto Marghera, whereas the lowest were measured near the Chioggia and Malamocco inlets, where an intense tidally-driven renewal of seawater takes place. Although CuCC showed a high degree of spatial variability, the values recorded in the Venice Lagoon are comparable to those reported in other estuarine systems. In addition, CuCC was positively correlated with dissolved organic carbon (DOC), suggesting that organic ligands responsible for Cu complexation are part of the bulk organic matter pool in the lagoon. The CuCC:Cu(T) molar ratio was, on average 55:1, indicating that a large excess of complexation capacity exists in the Venice Lagoon. The high levels of CuCC and the narrow range of pCu indicates the importance of the role played by organic ligands in controlling the free ion Cu concentrations in the lagoon, and as a consequence, regulating its availability and/or toxicity.

Hydrology and Salt Balance in a Large, Hypersaline Coastal Lagoon: Lagoa de Araruama, Brazil

NASA Astrophysics Data System (ADS)

Kjerfve, Björn; Schettini, C. A. F.; Knoppers, Bastiaan; Lessa, Guilherme; Ferreira, H. O.

1996-06-01

Lagoa de Araruama in the state of Rio de Janeiro, Brazil, is a hypersaline coastal lagoon as a result of semi-arid climate conditions, a small drainage basin and a choked entrance channel. The lagoon has been continuously hypersaline for at least 4·5 centuries, but the mean salinity has varied substantially. It has recently decreased from 57 to 52 as indicated by density (salinity) measurements between 1965 and 1990. Analysis of more than 20 years of salinity time series data, in addition to monthly lagoon cruises to measure the spatial salinity distribution, indicate that the lagoon salinity largely fluctuates in response to the difference between evaporation and precipitation. The major factor explaining the long-term trend of decreasing salinity in the lagoon is the constant pumping of 1 m 3s -1of freshwater to the communities surrounding the lagoon from an adjacent watershed, and subsequent discharge of this water into Lagoa de Araruama. The net salt budget is primarily a balance between the advective import of salt from the coastal ocean and eddy diffusive export of salt to the ocean, although the extensive mining of salt from the lagoon during past decades is also a small but significant contribution to the salt budget. The flushing half-life is proposed as a useful time scale of water exchange, is calculated based on a combination of hydrological and tidal processes, and is excellent for comparison of lagoons and assessing water quality changes. The flushing half-life measures 83·5 days for Lagoa de Araruama, considerably longer than for most other coastal lagoons. The proposed dredging of a second ocean channel to Lagoa de Araruama is probably not a good idea. It is likely to accelerate the decrease of lagoon salinity and somewhat improve the lagoon water exchange. At the same time, this will eliminate the apparent buffering capacity provided by the hypersaline environment, and thus may potentially cause water quality problems.

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.

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

Consistency of temporal and habitat-related differences among assemblages of fish in coastal lagoons

NASA Astrophysics Data System (ADS)

Gray, Charles A.; Rotherham, Douglas; Johnson, Daniel D.

2011-12-01

The consistency of habitat-related differences in coastal lagoon fish assemblages was assessed across different spatial and temporal scales. Multimesh gillnets were used to sample assemblages of fish on a monthly basis for 1-year in three habitats (shallow seagrass, shallow bare and deep substrata) at two locations (>1 km apart), in each of two coastal lagoons (approximately 500 km apart), in southeastern Australia. A total of 48 species was sampled with 34 species occurring in both lagoons and in all three habitats; species caught in only one lagoon or habitat occurred in low numbers. Ten species dominated assemblages and accounted for more than 83% of all individuals sampled. In both lagoons, assemblages in the deep habitat consistently differed to those in the shallow strata (regardless of habitat). Several species were caught more frequently or in larger numbers in the deep habitat. Assemblages in the two shallow habitats did not differ consistently and were dominated by the same species and sizes of fish, possibly due to habitat heterogeneity and the scale and method of sampling. Within each lagoon, very few between location differences in assemblages within each habitat were observed. Consistent differences in assemblages were detected between lagoons for the shallow bare and deep habitats, indicating there were some intrinsic differences in ichthyofauna between lagoons. Assemblages in spring differed to those in summer, which differed to those in winter for the shallow bare habitat in both lagoons, and the deep habitat in only one lagoon. Fish-habitat relationships are complex and differences in the fish fauna between habitats were often temporally inconsistent. This study highlights the need for greater testing of habitat relationships in space and time to assess the generality of observations and to identify the processes responsible for structuring assemblages.

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

Sustainability assessment of traditional fisheries in Cau Hai lagoon (South China Sea).

PubMed

Marconi, Michele; Sarti, Massimo; Marincioni, Fausto

2010-01-01

Overfishing and progressive environmental degradation of the Vietnamese Cau Hai coastal lagoon appear to be threatening the ecological integrity and water quality of the largest estuarine complex of Southeast Asia. This study assessed the relationships between the density of traditional fisheries and organic matter sedimentary contents in Cau Hai lagoon. Data revealed that the density of stake traps (the most common fishing gear used in this lagoon), decreasing hydrodynamic energy in shallow water, causes the accumulation of a large fraction of organic matter refractory to degradation. The relationship between biopolymeric carbon (a proxy of availability of organic matter) and stake traps density fits a S-shape curve. The logistic equation calculated a stake traps density of 90 m of net per hectare, as the threshold over which maximum accumulation of organic matter occurs in Cau Hai. With such level of stake trap density, and assuming a theoretical stationary status of the lagoon, the time necessary for the system to reach hypoxic conditions has been calculated to be circa three weeks. We recommend that this density threshold should not be exceeded in the Cau Hai lagoon and that further analyses of organic loads in the sediment should be conducted to monitor the trophic conditions of this highly eutrophicated lagoon. 2010 Elsevier Ltd. All rights reserved.

Microbial community analysis of swine wastewater anaerobic lagoons by next-generation DNA sequencing.

PubMed

Ducey, Thomas F; Hunt, Patrick G

2013-06-01

Anaerobic lagoons are a standard practice for the treatment of swine wastewater. This practice relies heavily on microbiological processes to reduce concentrated organic material and nutrients. Despite this reliance on microbiological processes, research has only recently begun to identify and enumerate the myriad and complex interactions that occur in this microbial ecosystem. To further this line of study, we utilized a next-generation sequencing (NGS) technology to gain a deeper insight into the microbial communities along the water column of four anaerobic swine wastewater lagoons. Analysis of roughly one million 16S rDNA sequences revealed a predominance of operational taxonomic units (OTUs) classified as belonging to the phyla Firmicutes (54.1%) and Proteobacteria (15.8%). At the family level, 33 bacterial families were found in all 12 lagoon sites and accounted for between 30% and 50% of each lagoon's OTUs. Analysis by nonmetric multidimensional scaling (NMS) revealed that TKN, COD, ORP, TSS, and DO were the major environmental variables in affecting microbial community structure. Overall, 839 individual genera were classified, with 223 found in all four lagoons. An additional 321 genera were identified in sole lagoons. The top 25 genera accounted for approximately 20% of the OTUs identified in the study, and the low abundances of most of the genera suggests that most OTUs are present at low levels. Overall, these results demonstrate that anaerobic lagoons have distinct microbial communities which are strongly controlled by the environmental conditions present in each individual lagoon. Published by Elsevier Ltd.

Tables of critical-flow functions and thermodynamic properties for methane and computational procedures for both methane and natural gas

NASA Technical Reports Server (NTRS)

Johnson, R. C.

1972-01-01

Procedures for calculating the mass flow rate of methane and natural gas through nozzles are given, along with the FORTRAN 4 subroutines used to make these calculations. Three sets of independent variables are permitted in these routines. In addition to the plenum pressure and temperature, the third independent variable is either nozzle exit pressure, Mach number, or temperature. A critical-flow factor that becomes a convenient means for determining the mass flow rate of methane through critical-flow nozzles is tabulated. Other tables are included for nozzle throat velocity and critical pressure, density, and temperature ratios, along with some thermodynamic properties of methane, including compressibility factor, enthalpy, entropy, specific heat, specific-heat ratio, and speed of sound. These tabulations cover a temperature range from 120 to 600 K and pressures to 3 million N/sq m.

Future evolution of a tidal inlet due to changes in wave climate, Sea level and lagoon morphology (Óbidos lagoon, Portugal)

NASA Astrophysics Data System (ADS)

Bruneau, Nicolas; Fortunato, André B.; Dodet, Guillaume; Freire, Paula; Oliveira, Anabela; Bertin, Xavier

2011-11-01

Tidal inlets are extremely dynamic, as a result of an often delicate balance between the effects of tides, waves and other forcings. Since the morphology of these inlets can affect navigation, water quality and ecosystem dynamics, there is a clear need to anticipate their evolution in order to promote adequate management decisions. Over decadal time scales, the position and size of tidal inlets are expected to evolve with the conditions that affect them, for instance as a result of climate change. A process-based morphodynamic modeling system is validated and used to analyze the effects of sea level rise, an expected shift in the wave direction and the reduction of the upper lagoon surface area by sedimentation on a small tidal inlet (Óbidos lagoon, Portugal). A new approach to define yearly wave regimes is first developed, which includes a seasonal behavior, random inter-annual variability and the possibility to extrapolate trends. Once validated, this approach is used to produce yearly time series of wave spectra for the present and for the end of the 21st century, considering the local rotation trends computed using hindcast results for the past 57 years. Predictions of the mean sea level for 2100 are based on previous studies, while the bathymetry of the upper lagoon for the same year is obtained by extrapolation of past trends. Results show, and data confirm, that the Óbidos lagoon inlet has three stable configurations, largely determined by the inter-annual variations in the wave characteristics. Both sea level rise and the reduction of the lagoon surface area will promote the accretion of the inlet. In contrast, the predicted rotation of the wave regime, within foreseeable limits, will have a negligible impact on the inlet morphology.

Groundwater and porewater as a major source of alkalinity to a fringing coral reef lagoon (Muri Lagoon, Cook Islands)

NASA Astrophysics Data System (ADS)

Cyronak, T.; Santos, I. R.; Erler, D. V.; Eyre, B. D.

2012-11-01

To better predict how ocean acidification will affect coral reefs, it is important to understand how biogeochemical cycles on reefs alter carbonate chemistry over various temporal and spatial scales. This study quantifies the contribution of fresh groundwater discharge (as traced by radon) and shallow porewater exchange (as quantified from advective chamber incubations) to total alkalinity (TA) dynamics on a fringing coral reef lagoon along the southern Pacific island of Rarotonga over a tidal and diel cycle. Benthic alkalinity fluxes were affected by the advective circulation of water through permeable sediments, with net daily flux rates of carbonate alkalinity ranging from -1.55 to 7.76 mmol m-2 d-1, depending on the advection rate. Submarine groundwater discharge (SGD) was a source of TA to the lagoon, with the highest flux rates measured at low tide, and an average daily TA flux of 1080 mmol m-2 d-1. Both sources of TA were important on a reef wide basis, although SGD acted solely as a delivery mechanism of TA to the lagoon, while porewater advection was either a sink or source of TA dependant on the time of day. On a daily basis, groundwater can contribute approximately 70% to 80% of the TA taken up by corals within the lagoon. This study describes overlooked sources of TA to coral reef ecosystems that can potentially alter water-column carbonate chemistry. We suggest that porewater and groundwater fluxes of TA should be taken into account in ocean acidification models in order to properly address changing carbonate chemistry within coral reef ecosystems.

Residence times in a hypersaline lagoon: Using salinity as a tracer

NASA Astrophysics Data System (ADS)

Mudge, Stephen M.; Icely, John D.; Newton, Alice

2008-04-01

Generally the waters of the Ria Formosa Lagoon, Portugal have a short residence time, in the order of 0.5 days (Tett, P., Gilpin, L., Svendsen, H., Erlandsson, C.P., Larsson, U., Kratzer, S., Fouilland, E., Janzen, C., Lee, J., Grenz, C., Newton, A., Ferreira, J.G., Fernandes, T., Scory, S., 2003. Eutrophication and some European waters of restricted exchange. Continental Shelf Research 23, 1635-1671). This estimation is based on the measurements of currents and the modelling of water exchange at the outlets to the ocean. However, observations of the temperature and salinity in the inner channels imply that residence time is greater in these regions of the lagoon. To resolve this apparent contradiction, spatial measurements of the temperature and salinity were made with a meter for conductivity, temperature and depth along the principal channels of the western portion of the lagoon, with a sampling frequency of two per second. Evaporation rates of 5.4 mm day -1 were measured in a salt extraction pond adjacent to the lagoon and used to determine the residence time through salinity differences with the incoming seawater. In June 2004, the water flooding in from the ocean had an average salinity of 36.07 which contrasted with a maximum of 37.82 at mid ebb on a spring tide, corresponding to a residence time of >7 days; the mean residence time was 2.4 days. As the tide flooded into the channels, the existing water was advected back into the lagoon. Although there was a small amount of mixing with water from another inlet, the water body from the inner lagoon essentially remained distinct with respect to temperature and salinity characteristics. The residence time of the water was further prolonged at the junction between the main channels, where distinct boundaries were observed between the different water masses. As the water ebbed out, the shallow Western Channel was essentially isolated from the rest of the outer lagoon, and the water from this channel was forced

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.

Spatial and temporal variation of water quality in the coastal lagoons of Sinaloa

NASA Astrophysics Data System (ADS)

Paez-Osuna, F.; Lopez-Aguiar, L. K.; Del Río-Chuljak, A.; Ruiz-Fernandez, A. C.

2007-05-01

The Mexican state of Sinaloa has 656 km of coastline and 221,600 ha of coastal lagoons, and is characterized by a high fishing and agriculture activity. It is well known that agricultural activities constitute a major factor affecting the water quality in the coastal waters. The current study focused on the 6 more important coastal lagoons of Sinaloa (Topolobampo-Ohuira-Santa María, Navachiste-San Ignacio-Macapule, Santa María-La Reforma, Altata-Ensenada del Pabellón, Ceuta and Teacapán-Agua Brava) with the aim to evaluate the water quality spatial and temporal variation at the lagoons (physico-chemical parameters, nutrients (N, P and Si), dissolved oxygen, total suspended solids and chlorophyll a) and to assess its eutrophication status. The water samples were collected in several stations at each lagoon (between 9 and 23 stations depending on the lagoon area) at low and high tides, during three different weather periods (dry-warm, rainy and dry-cold seasons) between May 2004 and April 2005. Mean concentrations of nutrients (μM), dissolved oxygen (mg/L) and chlorophyll a (mg/m3) obtained for each variable were comparable between lagoons (total N=51±45; total P= 2.5±1.5; Si=23±31; DO=6.7±1.8; Chll=1.7±1.9) although seasonal and spatial differences were observed at each lagoon. The nutrient concentrations measured fell in the typical concentration intervals for coastal lagoons; however, critical sampling points were identified and related to direct discharges of untreated effluents from municipal wastes, aquaculture farms and agriculture drain ditches.

Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

NASA Astrophysics Data System (ADS)

Borowski, Marek; Kuczera, Zbigniew

2018-03-01

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

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

Marshall Islands Fringing Reef and Atoll Lagoon Observations of the Tohoku Tsunami

NASA Astrophysics Data System (ADS)

Ford, Murray; Becker, Janet M.; Merrifield, Mark A.; Song, Y. Tony

2014-12-01

The magnitude 9.0 Tohoku earthquake on 11 March 2011 generated a tsunami which caused significant impacts throughout the Pacific Ocean. A description of the tsunami within the lagoons and on the surrounding fringing reefs of two mid-ocean atoll islands is presented using bottom pressure observations from the Majuro and Kwajalein atolls in the Marshall Islands, supplemented by tide gauge data in the lagoons and by numerical model simulations in the deep ocean. Although the initial wave arrival was not captured by the pressure sensors, subsequent oscillations on the reef face resemble the deep ocean tsunami signal simulated by two numerical models, suggesting that the tsunami amplitudes over the atoll outer reefs are similar to that in deep water. In contrast, tsunami oscillations in the lagoon are more energetic and long lasting than observed on the reefs or modelled in the deep ocean. The tsunami energy in the Majuro lagoon exhibits persistent peaks in the 30 and 60 min period bands that suggest the excitation of closed and open basin normal modes, while energy in the Kwajalein lagoon spans a broader range of frequencies with weaker, multiple peaks than observed at Majuro, which may be associated with the tsunami behavior within the more irregular geometry of the Kwajalein lagoon. The propagation of the tsunami across the reef flats is shown to be tidally dependent, with amplitudes increasing/decreasing shoreward at high/low tide. The impact of the tsunami on the Marshall Islands was reduced due to the coincidence of peak wave amplitudes with low tide; however, the observed wave amplitudes, particularly in the atoll lagoon, would have led to inundation at different tidal phases.

Trace metals in sediments of two estuarine lagoons from Puerto Rico.

PubMed

Acevedo-Figueroa, D; Jiménez, B D; Rodríguez-Sierra, C J

2006-05-01

Concentrations of As, Cd, Cu, Fe, Hg, Pb and Zn were evaluated in surface sediments of two estuaries from Puerto Rico, known as San José Lagoon (SJL) and Joyuda Lagoon. Significantly higher concentrations in microg/g dw of Cd (1.8 vs. 0.1), Cu (105 vs. 22), Hg (1.9 vs. 0.17), Pb (219 vs. 8), and Zn (531 vs. 52) were found in sediment samples from SJL when compared to Joyuda Lagoon. Average concentrations of Hg, Pb, and Zn in some sediment samples from SJL were above the effect range median (ERM) that predict toxic effects to aquatic organisms. Enrichments factors using Fe as a normalizer, and correlation matrices showed that metal pollution in SJL was the product of anthropogenic sources, while the metal content in Joyuda Lagoon was of natural origins. Sediment metal concentrations found in SJL were comparable to aquatic systems classified as contaminated from other regions of the world.

Characterizing non-methane volatile organic compounds emissions from a swine concentrated animal feeding operation

NASA Astrophysics Data System (ADS)

Rumsey, Ian C.; Aneja, Viney P.; Lonneman, William A.

2012-02-01

Emissions of non-methane volatile organic compounds (NMVOCs) were determined from a swine concentrated animal feeding operation (CAFO) in North Carolina. NMVOCs were measured in air samples collected in SUMMA and fused-silica lined (FSL) canisters and were analyzed using a gas chromatography flame ionization detection (GC-FID) system. Measurements were made from both an anaerobic lagoon and barn in each of the four seasonal sampling periods during the period June 2007 through April 2008. In each sampling period, nine to eleven canister samples were taken from both the anaerobic lagoon and barn over a minimum of four different days during a period of ˜1 week. Measurements of meteorological and physiochemical parameters were also made during the sampling period. In lagoon samples, six NMVOCs were identified that had significantly larger emissions in comparison to other NMVOCs. This included three alcohols (ethanol, 2-ethyl-1-hexanol, and methanol), two ketones (acetone and methyl ethyl ketone (MEK)) and an aldehyde (acetaldehyde). The overall average fluxes for these NMVOCs, ranged from 0.18 μg m -2 min -1 for 2-ethyl-1-hexanol to 2.11 μg m -2 min -1 for acetone, with seasonal fluxes highest in the summer for four (acetone, acetaldehyde, 2-ethyl-1-hexanol and MEK) of the six compounds In barn samples, there were six NMVOCs that had significantly larger concentrations and emissions in comparison to other NMVOCs. These consisted of two alcohols (methanol and ethanol), an aldehyde (acetaldehyde), two ketones (acetone and 2,3-butanedione), and a phenol (4-methylphenol). Overall average barn concentration ranged from 2.87 ppb for 4-methylphenol to 16.12 ppb for ethanol. Overall average normalized barn emission rates ranged from 0.10 g day -1 AU -1 (1 AU (animal unit) = 500 kg of live animal weight) for acetaldehyde to 0.45 g day -1 AU -1 for ethanol. The NMVOCs, 4-methylphenol and 2,3-butanedione, which have low odor thresholds (odor thresholds = 1.86 ppb and 0

Project summary. PERSISTENCE OF PATHOGENS IN LAGOON-STORED SLUDGE (EPA/600/S2-89/015)

EPA Science Inventory

The project objective was to investigate pathogen inactlvation in lagoon-stored municipal sludges. The in-field lagoons were located in Louisiana (New Orleans) and in Texas (Port Aransas), both semitropical areas of the United States. Each lagoon was filled with 7.56 mL of ...

Survey of Large Methane Emitters in North America

NASA Astrophysics Data System (ADS)

Deiker, S.

2017-12-01

It has been theorized that methane emissions in the oil and gas industry follow log normal or "fat tail" distributions, with large numbers of small sources for every very large source. Such distributions would have significant policy and operational implications. Unfortunately, by their very nature such distributions would require large sample sizes to verify. Until recently, such large-scale studies would be prohibitively expensive. The largest public study to date sampled 450 wells, an order of magnitude too low to effectively constrain these models. During 2016 and 2017, Kairos Aerospace conducted a series of surveys the LeakSurveyor imaging spectrometer, mounted on light aircraft. This small, lightweight instrument was designed to rapidly locate large emission sources. The resulting survey covers over three million acres of oil and gas production. This includes over 100,000 wells, thousands of storage tanks and over 7,500 miles of gathering lines. This data set allows us to now probe the distribution of large methane emitters. Results of this survey, and implications for methane emission distribution, methane policy and LDAR will be discussed.

Bacterioplankton diversity and community composition in the Southern Lagoon of Venice.

PubMed

Simonato, Francesca; Gómez-Pereira, Paola R; Fuchs, Bernhard M; Amann, Rudolf

2010-04-01

The Lagoon of Venice is a large water basin that exchanges water with the Northern Adriatic Sea through three large inlets. In this study, the 16S rRNA approach was used to investigate the bacterial diversity and community composition within the southern basin of the Lagoon of Venice and at one inlet in October 2007 and June 2008. Comparative sequence analysis of 645 mostly partial 16S rRNA gene sequences indicated high diversity and dominance of Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes at the lagoon as well as at the inlet station, therefore pointing to significant mixing. Many of these sequences were close to the 16S rRNA of marine, often coastal, bacterioplankton, such as the Roseobacter clade, the family Vibrionaceae, and class Flavobacteria. Sequences of Actinobacteria were indicators of a freshwater input. The composition of the bacterioplankton was quantified by catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) with a set of rRNA-targeted oligonucleotide probes. CARD-FISH counts corroborated the dominance of members of the phyla Alphaproteobacteria, Gammaproteobacteria and Bacteroidetes. When assessed by a probe set for the quantification of selected clades within Alphaproteobacteria and Gammaproteobacteria, bacterioplankton composition differed between October 2007 and June 2008, and also between the inlet and the lagoon. In particular, members of the readily culturable copiotrophic gammaproteobacterial genera Vibrio, Alteromonas and Pseudoalteromonas were enriched in the southern basin of the Lagoon of Venice. Interestingly, the alphaproteobacterial SAR11 clade and related clusters were also present in high abundances at the inlet and within the lagoon, which was indicative of inflow of water from the open sea.

Wet soil cover applicability and design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunter, F.; Feenstra, S.; Hwang, D.

1996-12-31

As part of a focused feasibility study for the Tyson Superfund site, Daekyoo Hwang, then with ERM, developed a flooding/flushing option. It was not considered a viable option due to concerns over contaminated groundwater control. The concept, however, had several attractive features: control of VOC emissions; the downward movement of water prevents contamination of the overlying clean soil by the upward movement of contaminated soil vapor; and some natural attenuation of the contaminated lagoon area soils. The new concept employs a near saturated soil layer to prevent VOC emission and the downward movement of water to prevent contamination of surfacemore » soil. The wet soil cover became one of five alternatives submitted as part of the focused feasibility study. It was selected as the remedial option for the site by the USEPA. The study was reviewed by the public and they also were positive as to the use of a wet soil cover to control VOC emissions at the site. The wet soil cover is currently being designed by Smith Environmental.« less

Chasing boundaries and cascade effects in a coupled barrier - marshes - lagoon system

NASA Astrophysics Data System (ADS)

Lorenzo Trueba, J.; Mariotti, G.

2015-12-01

Low-lying coasts are often characterized by barriers islands, shore-parallel stretches of sand separated from the mainland by marshes and lagoons. We built an exploratory numerical model to examine the morphological feedbacks within an idealized barrier - marshes -lagoon system and predict its evolution under projected rates of sea level rise and sediment supply to the backbarrier environment. Our starting point is a recently developed morphodynamic model, which couples shoreface evolution and overwash processes in a dynamic framework. As such, the model is able to capture dynamics not reproduced by morphokinematic models, which advect geometries without specific concern to processes. These dynamics include periodic barrier retreat due to time lags in the shoreface response to barrier overwash, height drowning due to insufficient overwash fluxes as sea level rises, and width drowning, which occurs when the shoreface response rate is insufficient to maintain the barrier geometry during overwash-driven landward migration. We extended the model by coupling the barrier model with a model for the evolution of the marsh platform and the boundary between the marsh and the adjacent lagoon. The coupled model explicitly describes marsh edge processes and accounts for the modification of the wave regime associated with lagoon width (fetch). Model results demonstrate that changes in factors that are not typically associated with the dynamics of coastal barriers, such as the lagoon width and the rate of export/import of sediments from and to the lagoon, can lead to previously unidentified complex responses of the coupled system. In particular, a wider lagoon in the backbarrier, and/or a reduction in the supply of muddy sediments to the backbarrier, can increase barrier retreat rates and even trigger barrier drowning. Overall, our findings highlight the importance of incorporating backbarrier dynamics in models that aim at predicting the response of barrier systems.

Trace Metal Accumulation In The Thau Coastal Lagoon and Its Possible Impact On The Waters of The Gulf of Lion In The Mediterranean

NASA Astrophysics Data System (ADS)

Abdullah, M. I.; Elbaz-Poulichet, Francoise

Coastal lagoons are important marine environments for fisheries resources, wild life sanctuaries as well as many other economic activities. The Thau lagoon (at Sette, south coast of france) a major shell fisheries development in the region, receives inputs from a variety of sources namely seasonal run-off, river discharge, manmade waterways, karstic and thermal underground waters. A wide variety of material is thus added to the lagoon particularly trace metals such as Cu, Zn, Pb, Fe, Mn etc. . Metals added through karstic and thermal waters are particularly significant. Althought the lagoon covers some 75 km2, it is shallow with a maximum depth of only 9 m and with exchange with the Mediterranean being restricted along the narrow canal de Sette. Consequently, metal level can build up to quite high concentration upto x30 of that for normal seawater par- ticularly for metals such as Pb and Cu. While water exchange is severely limited, ma- jor water replacement do occur particularly during prolonged turbulent weather con- ditions with sustained onshore/offshore winds. Such episode occurred during March 2000 when it was observed that a significant proportion of the Thau lagoon was re- place by Mediterranean water. This water was characterized by it lower metal content and REE distribution. Such episodes are known to occur several times annually caus- ing significant amounts of metal-rich Thau water to discharge into the Gulf of Lion. It is concluded that such episodic exchanges constitute an important source of metals to the coastal zone and the Gulf of Lion which has been previously reported to have elevated metal levels.

Impact of mussel bioengineering on fine-grained sediment dynamics in a coastal lagoon: A numerical modelling investigation

NASA Astrophysics Data System (ADS)

Forsberg, Pernille L.; Lumborg, Ulrik; Bundgaard, Klavs; Ernstsen, Verner B.

2017-12-01

Rødsand lagoon in southeast Denmark is a non-tidal coastal lagoon. It is home to a wide range of marine flora and fauna and part of the Natura 2000 network. An increase in turbidity through elevated levels of suspended sediment concentration (SSC) within the lagoon may affect the ecosystem health due to reduced light penetration. Increasing SSC levels within Rødsand lagoon could be caused by increasing storm intensity or by a sediment spill from dredging activities west of the lagoon in relation to the planned construction of the Fehmarnbelt fixed link between Denmark and Germany. The aim of the study was to investigate the impact of a mussel reef on sediment import and SSC in a semi-enclosed lagoon through the development of a bioengineering modelling application that makes it possible to include the filtrating effect of mussels in a numerical model of the lagoonal system. The numerical implementation of an exterior mussel reef generated a reduction in the SSC in the vicinity of the reef, through the adjacent inlet and in the western part of the lagoon. The mussel reef reduced the sediment import to Rødsand lagoon by 13-22% and reduced the SSC within Rødsand lagoon by 5-9% depending on the filtration rate and the reef length. The results suggest that the implementation of a mussel reef has the potential to relieve the pressure of increasing turbidity levels within a semi-enclosed lagoonal system. However, further assessment and development of the bioengineering application and resulting ecosystem impacts are necessary prior to actual implementation.

Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeremy Semrau; Sung-Woo Lee; Jeongdae Im

2010-09-30

The overall objective of this project, 'Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils' was to develop effective, efficient, and economic methodologies by which microbial production of nitrous oxide can be minimized while also maximizing microbial consumption of methane in landfill cover soils. A combination of laboratory and field site experiments found that the addition of nitrogen and phenylacetylene stimulated in situ methane oxidation while minimizing nitrous oxide production. Molecular analyses also indicated that methane-oxidizing bacteria may play a significant role in not only removing methane, but in nitrous oxide production as well, although themore » contribution of ammonia-oxidizing archaea to nitrous oxide production can not be excluded at this time. Future efforts to control both methane and nitrous oxide emissions from landfills as well as from other environments (e.g., agricultural soils) should consider these issues. Finally, a methanotrophic biofiltration system was designed and modeled for the promotion of methanotrophic activity in local methane 'hotspots' such as landfills. Model results as well as economic analyses of these biofilters indicate that the use of methanotrophic biofilters for controlling methane emissions is technically feasible, and provided either the costs of biofilter construction and operation are reduced or the value of CO{sub 2} credits is increased, can also be economically attractive.« less

Analysis of the unique geothermal microbial ecosystem of the Blue Lagoon.

PubMed

Petursdottir, Solveig K; Bjornsdottir, Snaedis H; Hreggvidsson, Gudmundur O; Hjorleifsdottir, Sigridur; Kristjansson, Jakob K

2009-12-01

Cultivation and culture-independent techniques were used to describe the geothermal ecosystem of the Blue Lagoon in Iceland. The lagoon contains both seawater and freshwater of geothermal origin and is extremely high in silica content. Water samples were collected repeatedly in summer and autumn in 2003 and 2005 and in winter 2006 were analyzed for species composition. The study revealed the typical traits of an extreme ecosystem characterized by dominating species and other species represented in low numbers. A total of 35 taxa were identified. The calculated biodiversity index of the samples was 2.1-2.5. The majority (83%) of analyzed taxa were closely related to bacteria of marine and geothermal origin reflecting a marine character of the ecosystem and the origin of the Blue Lagoon hydrothermal fluid. A high ratio (63%) of analyzed taxa represented putative novel bacterial species. The majority (71%) of analyzed clones were Alphaproteobacteria, of which 80% belonged to the Roseobacter lineage within the family of Rhodobacteraceae. Of seven cultivated species, the two most abundant ones belonged to this lineage. Silicibacter lacuscaerulensis was confirmed as a dominating species in the Blue Lagoon. One group of isolates represented a recently identified species within the genus of Nitratireductor within Rhizobiales. This study implies an annually stable and seasonally dynamic ecosystem in the Blue Lagoon.

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.

Variability of methane fluxes over high latitude permafrost wetlands

NASA Astrophysics Data System (ADS)

Serafimovich, Andrei; Hartmann, Jörg; Larmanou, Eric; Sachs, Torsten

2013-04-01

Atmospheric methane plays an important role in the global climate system. Due to significant amounts of organic material stored in the upper layers of high latitude permafrost wetlands and a strong Arctic warming trend, there is concern about potentially large methane emissions from Arctic and sub-Arctic areas. The quantification of methane fluxes and their variability from these regions therefore plays an important role in understanding the Arctic carbon cycle and changes in atmospheric methane concentrations. However, direct measurements of methane fluxes in permafrost regions are sparse, very localized, inhomogeneously distributed in space, and thus difficult to use for accurate model representation of regional to global methane contributions from the Arctic. We aim to contribute to reducing uncertainty and improve spatial coverage and spatial representativeness of flux estimates by using airborne eddy covariance measurements across large areas. The research aircraft POLAR 5 was equipped with a turbulence nose boom and a fast response methane analyzer and served as the platform for measurements of methane emissions. The measuring campaign was carried out from 28 June to 10 July 2012 across the entire North Slope of Alaska and the Mackenzie Delta in Canada. The supplemented simulations from the Weather Research and Forecasting (WRF) model exploring the dynamics of the atmospheric boundary layer were used to analyze high methane concentrations occasionally observed within the boundary layer with a distinct drop to background level above. Strong regional differences were detected over both investigated areas showing the non-uniform distribution of methane sources. In order to cover the whole turbulent spectrum and at the same time to resolve methane fluxes on a regional scale, different integration paths were analyzed and validated through spectral analysis. Methane emissions measured over the Mackenzie Delta were higher and generally more variable in space

Changes in sludge accumulation of anaerobic swine lagoons receiving pretreated influent

USDA-ARS?s Scientific Manuscript database

This study evaluated the changes in sludge depth and volume of anaerobic swine lagoon in North Carolina after six years of applying treatment to the liquid flushed manure prior to entering the lagoon. The farm had seven swine barns with a permitted capacity of 5,145 head feeder to finish (735 head/b...

Whiteriver Sewage Lagoons, Whiteriver, AZ: AZ0024058

EPA Pesticide Factsheets

Authorization to Discharge Under National Pollutant Discharge Elimination System (NPDES) Permit No. AZ0024058 for Tribal Utility Authority, White Mountain Apache Tribe Whiteriver Sewage Lagoons, Whiteriver, AZ.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Are Sea Surface Temperature satellite measurements reliable proxies of lagoon temperature in the South Pacific?

NASA Astrophysics Data System (ADS)

Van Wynsberge, Simon; Menkes, Christophe; Le Gendre, Romain; Passfield, Teuru; Andréfouët, Serge

2017-12-01

In remote coral reef environments, lagoon and reef in situ measurements of temperature are scarce. Sea Surface Temperature (SST) measured by satellite has been frequently used as a proxy of the lagoon temperature experienced by coral reef organisms (TL) especially during coral bleaching events. However, the link between SST and TL is poorly characterized. First, we compared the correlation between various SST series and TL from 2012 to 2016 in three atolls and one island in the Central South Pacific Ocean. Simple linear correlation between SST and TL ranged between 0.44 and 0.97 depending on lagoons, localities of sensors, and type of SST data. High-resolution-satellite-measurements of SST inside the lagoons did not outperform oceanic SST series, suggesting that SST products are not adapted for small lagoons. Second, we modelled the difference between oceanic SST and TL as a function of the drivers of lagoon water renewal and mixing, namely waves, tide, wind, and season. The multivariate models reduced significantly the bias between oceanic SST and TL. In atoll lagoons, and probably in other hydrodynamically semi-open systems, a correction taking into account these factors is necessary when SST are used to characterize organisms' thermal stress thresholds.

[Species and size composition of fishes in Barra de Navidad lagoon, Mexican central Pacific].

PubMed

González-Sansón, Gaspar; Aguilar-Betancourt, Consuelo; Kosonoy-Aceves, Daniel; Lucano-Ramírez, Gabriela; Ruiz-Ramírez, Salvador; Flores-Ortega, Juan Ramón; Hinojosa-Larios, Angel; de Asís Silva-Bátiz, Francisco

2014-03-01

Coastal lagoons are considered important nursery areas for many coastal fishes. Barra de Navidad coastal lagoon (3.76km2) is important for local economy as it supports tourism development and artisanal fisheries. However, the role of this lagoon in the dynamics of coastal fish populations is scarcely known. Thus, the objectives of this research were: to characterize the water of the lagoon and related weather conditions, to develop a systematic list of the ichthyofauna, and to estimate the proportion of juveniles in the total number of individuals captured of most abundant species. Water and fish samples were collected between March 2011 and February 2012. Physical and chemical variables were measured in rainy and dry seasons. Several fishing gears were used including a cast net, beach purse seine and gillnets of four different mesh sizes. Our results showed that the lagoon is most of the time euhaline (salinity 30-40ups), although it can be mixopolyhaline (salinity 18-30ups) during short periods. Chlorophyll and nutrients concentrations suggested eutrophication in the lagoon. Mean water temperature changed seasonally from 24.9 degrees C (April, high tide) to 31.4 degrees C (October, low tide). Considering ichthyofauna species, a total of 36 448 individuals of 92 species were collected, 31 of them adding up to 95% of the total of individuals caught. Dominant species were Anchoa spp. (44.6%), Diapterus peruvianus (10.5%), Eucinostomus currani (8.1%), Cetengraulis mysticetus (7.8%), Mugil curema (5.2%) and Opisthonema libertate (4.5%). The lagoon is an important juvenile habitat for 22 of the 31 most abundant species. These included several species of commercial importance such as snappers (Lutjanus argentiventris, L. colorado and L. novemfasciatus), snook (Centropomus nigrescens) and white mullet (Mugil curema). Other four species seem to use the lagoon mainly as adults. This paper is the first contribution on the composition of estuarine ichthyofauna in Jalisco

Spatial variability in fish species assemblage and community structure in four subtropical lagoons of the Okavango Delta, Botswana

NASA Astrophysics Data System (ADS)

Mosepele, K.; Mosepele, B.; Bokhutlo, T.; Amutenya, K.

The species assemblage and community structure of four lagoons was assessed through time series data collected between 2001 and 2005 in the Okavango Delta. The main aim of this study was to evaluate the importance of lagoons as fish habitats in the Delta. Therefore, this study assessed the importance of these habitats through determining fish species diversity, composition, relative abundance, and community structure between the lagoons. Forty six species belonging to 11 families and five orders were collected over the study period. Main results showed that Cichlidae was the most important family and had the highest species richness in the lagoons. Significant differences ( p < 0.05) were observed in species richness, faunal composition, and diversity among some of the lagoons. Moreover, there were also variations in species composition, and also significant differences in mean length and weight of some selected fish species in the four lagoons. This study showed that lagoons are important repositories of food fish to local communities. Moreover, a management of the fish stocks based on restricting fishing in some lagoons as protected areas is not feasible because of these significant differences in species assemblages between lagoons. Furthermore, lagoons are subject to multiple where most of the lodges are constructed, which makes subsequently makes them vulnerable to pollution. Therefore, the integrity of lagoon habitats needs to be maintained so that their ecosystem functioning (i.e. fish repositories) is maintained.

Monitoring benthic foraminiferal dynamics at Bottsand coastal lagoon (western Baltic Sea)

NASA Astrophysics Data System (ADS)

Schönfeld, Joachim

2018-04-01

Benthic foraminifera from Bottsand coastal lagoon, western Baltic Sea, have been studied since the mid-1960s. They were monitored annually in late autumn since 2003 at the terminal ditch of the lagoon. There were 12 different species recognised, of which three have not been recorded during earlier investigations. Dominant species showed strong interannual fluctuations and a steady increase in population densities over the last decade. Elphidium incertum, a stenohaline species of the Baltic deep water fauna, colonised the Bottsand lagoon in 2016, most likely during a period of salinities >19 units and water temperatures of 18 °C on average in early autumn. The high salinities probably triggered their germination from a propagule bank in the ditch bottom sediment. The new E. incertum population showed densities higher by an order of magnitude than those of the indigenous species. The latter did not decline, revealing that E. incertum used another food source or occupied a different microhabitat. Elphidium incertum survived transient periods of lower salinities in late autumn 2017, though with reduced abundances, and became a regular faunal constituent at the Bottsand lagoon.

Chasing boundaries and cascade effects in a coupled barrier-marsh-lagoon system

NASA Astrophysics Data System (ADS)

Lorenzo-Trueba, Jorge; Mariotti, Giulio

2017-08-01

The long-term dynamic evolution of an idealized barrier-marsh-lagoon system experiencing sea-level rise is studied by coupling two existing numerical models. The barrier model accounts for the interaction between shoreface dynamics and overwash flux, which allows the occurrence of barrier drowning. The marsh-lagoon model includes both a backbarrier marsh and an interior marsh, and accounts for the modification of the wave regime associated with changes in lagoon width and depth. Overwash, the key process that connects the barrier shoreface with the marsh-lagoon ecosystems, is formulated to account for the role of the backbarrier marsh. Model results show that a number of factors that are not typically associated with the dynamics of coastal barriers can enhance the rate of overwash-driven landward migration by increasing backbarrier accommodation space. For instance, lagoon deepening could be triggered by marsh edge retreat and consequent export of fine sediment via tidal dispersion, as well as by an expansion of inland marshes and consequent increase in accommodation space to be filled in with sediment. A deeper lagoon results in a larger fraction of sediment overwash being subaqueous, which coupled with a slow shoreface response sending sediment onshore can trigger barrier drowning. We therefore conclude that the supply of fine sediments to the back-barrier and the dynamics of both the interior and backbarrier marsh can be essential for maintaining the barrier system under elevated rates of sea-level rise. Our results highlight the importance of considering barriers and their associated backbarriers as part of an integrated system in which sediment is exchanged.

Assessment of the trophic state of a hypersaline-carbonatic environment: Vermelha Lagoon (Brazil)

PubMed Central

Martins, Maria Virginia Alves; Frontalini, Fabrizio; Ballalai, João M.; Belart, Pierre; Habib, Renan; Fontana, Luiz F.; Clemente, Iara M. M. M.; Lorini, Maria Lucia; Mendonça Filho, João G.; Laut, Vanessa M.; Figueiredo, Marcos de Souza Lima

2017-01-01

Vermelha Lagoon is a hypersaline shallow transitional ecosystem in the state of Rio de Janeiro (Brazil). This lagoon is located in the protected area of Massambaba, between the cities of Araruama and Saquarema (Brazil), and displays two quite uncommon particularities: it exhibits carbonate sedimentation and displays the development of Holocene stromatolites. Due to both particularities, the salt industry and property speculation have been, increasingly, generating anthropic pressures on this ecosystem. This study aims to apply a multiproxy approach to evaluate the trophic state of Vermelha Lagoon based on physicochemical parameters and geochemical data for the quantification and qualification of organic matter (OM), namely total organic carbon (TOC), total sulfur (TS), total phosphorus (TP) and biopolymeric carbon (BPC), including carbohydrates (CHO), lipids (LIP) and proteins (PTN). The CHO/TOC ratio values suggest that OM supplied to the sediment is of autochthonous origin and results, essentially, from microbial activity. The cluster analyses allowed the identification of four regions in Vermelha Lagoon. The Region I included stations located in shallow areas of the eastern sector of Vermelha lagoon affected by the impact of the artificial channel of connection with Araruama Lagoon. The Region II, under the influence of salt pans, is characterized by the highest values of BPC, namely CHO promoted by microbiological activity. The Region III include stations spread through the lagoon with high values of dissolved oxygen and lower values of TP. Stromatolites and microbial mattes growth was observed in some stations of this sector. Region IV, where the highest values of TOC and TS were found, represents depocenters of organic matter, located in general in depressed areas. Results of this work evidences that the Vermelha Lagoon is an eutrophic but alkaline and well oxygenated environment (at both water column and surface sediment) where the autotrophic activity is

Induction of Purple Sulfur Bacterial Growth in Dairy Wastewater Lagoons by Circulation

USDA-ARS?s Scientific Manuscript database

Aims: To determine if circulation of diary wastewater induces the growth of phototrophic purple sulfur bacteria (PSB). Methods and Results: Two dairy wastewater lagoons that were similar in size, geographic location, number and type of cattle loading the lagoons were chosen. The only obvious diffe...

Assessing hog lagoon waste contamination in the Cape Fear Watershed using Bacteroidetes 16S rRNA gene pyrosequencing.

PubMed

Arfken, Ann M; Song, Bongkeun; Mallin, Michael A

2015-09-01

Hog lagoons can be major sources of waste and nutrient contamination to watersheds adjacent to pig farms. Fecal source tracking methods targeting Bacteroidetes 16S rRNA genes in pig fecal matter may underestimate or fail to detect hog lagoon contamination in riverine environments. In order to detect hog lagoon wastewater contamination in the Cape Fear Watershed, where a large number of hog farms are present, we conducted pyrosequencing analyses of Bacteroidetes 16S rRNA genes in hog lagoon waste and identified new hog lagoon-specific marker sequences. Additional pyrosequencing analyses of Bacteroidetes 16S rRNA genes were conducted with surface water samples collected at 4 sites during 5 months in the Cape Fear Watershed. Using an operational taxonomic unit (OTU) identity cutoff value of 97 %, these newly identified hog lagoon markers were found in 3 of the river samples, while only 1 sample contained the pig fecal marker. In the sample containing the pig fecal marker, there was a relatively high percentage (14.1 %) of the hog lagoon markers and a low pig fecal marker relative abundance of 0.4 % in the Bacteroidetes 16S rRNA gene sequences. This suggests that hog lagoon contamination must be somewhat significant in order for pig fecal markers to be detected, and low levels of hog lagoon contamination cannot be detected targeting only pig-specific fecal markers. Thus, new hog lagoon markers have a better detection capacity for lagoon waste contamination, and in conjunction with a pig fecal marker, provide a more comprehensive and accurate detection of hog lagoon waste contamination in susceptible watersheds.

Assessing hydrological effects of human interventions on coastal systems: numerical applications to the Venice Lagoon

NASA Astrophysics Data System (ADS)

Ferrarin, C.; Ghezzo, M.; Umgiesser, G.; Tagliapietra, D.; Camatti, E.; Zaggia, L.; Sarretta, A.

2013-05-01

The hydrological consequences of historical, contemporary and future human activities on a coastal system were investigated by means of numerical models. The changes in the morphology of the Lagoon of Venice during the last century result from the sedimentological response to the combined effects of human interventions on the environment and global changes. This study focuses on changes from 1927 to 2012 and includes the changes planned for the protection of the city of Venice from storm surges and exceptional tides under future sea level rise scenarios. The application of a hydrodynamic model allowed for the analysis of the morphological effects on the lagoon circulation, the interaction with the sea and the internal mixing processes. The absolute values of the exchange between the lagoon and sea increased from 1927 to 2002 (from 3900 to 4600 m3 s-1), while the daily fraction of lagoon water volume exchanged decreased. At the same time, the flattening of the lagoon and loss of morphological heterogeneity enhanced the internal mixing processes driven by the tide and wind, reducing thus the overall water renewal time from 11.9 days in 1927 to 10.8 days in 2002. Morphological changes during the last decade reduced the water exchange through the inlets and induced an increase of the basin-wide water renewal time of 0.5 day. In the future, Venice Lagoon will evolve to a more restricted environment due to sea level rise, which increases the lagoon volume, and periodical closure of the lagoon from the sea during flooding events, which reduces the communication with the open sea. Therefore, the flushing capacity of the lagoon will decrease considerably, especially in its central part. Furthermore, some considerations on the impact of the hydromorphological changes on the ecological dynamics are proposed.

Hubble reveals heart of Lagoon Nebula

NASA Image and Video Library

2010-09-22

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

Modelling alpha-diversities of coastal lagoon fish assemblages from the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Riera, R.; Tuset, V. M.; Betancur-R, R.; Lombarte, A.; Marcos, C.; Pérez-Ruzafa, A.

2018-07-01

Coastal lagoons are marine ecosystems spread worldwide with high ecological value; however, they are increasingly becoming deteriorated as a result of anthropogenic activity. Their conservation requires a better understanding of the biodiversity factors that may help identifying priority areas. The present study is focused on 37 Mediterranean coastal lagoons and we use predictive modelling approaches based on Generalized Linear Model (GLM) analysis to investigate variables (geomorphological, environmental, trophic or biogeographic) that may predict variations in alpha-diversity. It included taxonomic diversity, average taxonomic distinctness, and phylogenetic and functional diversity. Two GLM models by index were built depending on available variables for lagoons: in the model 1 all lagoons were used, and in the model 2 only 23. All alpha-diversity indices showed variability between lagoons associated to exogenous factors considered. The biogeographic region strongly conditioned most of models, being the first variable introduced in the models. The salinity and chlorophyll a concentration played a secondary role for the models 1 and 2, respectively. In general, the highest values of alpha-diversities were found in northwestern Mediterranean (Balearic Sea, Alborán Sea and Gulf of Lion), hence they might be considered "hotspots" at the Mediterranean scale and should have a special status for their protection.

Pan-European management of coastal lagoons: A science-policy-stakeholder interface perspective

NASA Astrophysics Data System (ADS)

Lillebø, Ana I.; Stålnacke, Per; Gooch, Geoffrey D.; Krysanova, Valentina; Bielecka, Małgorzata

2017-11-01

The main objective of the work carried out in the scope of a three years collaborative research project was to develop science-based strategies and a decision support framework for the integrated management of coastal lagoons and their catchments and, in this context, to enhance connectivity between research and policymaking. In this paper our main objective is to share the lessons learned from the innovative methodology used throughout the project. To achieve the proposed objectives, the multidisciplinary scientific knowledge in the project team was combined and integrated with the knowledge and views of local stakeholders of four selected European coastal lagoons, using a three step participatory approach. With this innovative approach, which included the usage of eco-hydrological and water quality-modelling tools, the team developed and analyzed integrated scenarios of possible economic development and environmental impacts in four European lagoons and their catchments. These scenarios were presented and discussed with stakeholders, giving rise to management recommendations for each case study lagoon. Results show that some management options might be transferrable to other European lagoons having similar climatic, geophysical and socio-economic settings. In management terms, the project output provides a set of policy guidelines derived from the different analyses conducted and proposes initiatives concerning management implementation in a local-regional-national-European setting.

Lagoon-sea exchanges, nutrient dynamics and water quality management of the Ria Formosa (Portugal)

NASA Astrophysics Data System (ADS)

Newton, Alice; Mudge, Stephen M.

2005-02-01

Historical data from the Ria Formosa lagoon are classified according to the EEA 2001 guidelines to provide a frame of reference to evaluate the effect of management during the implementation of the environmental legislative Directives. Water samples from the Ria Formosa lagoon were significantly enriched in nitrogen (NH 4+ NO 2- and NO 3-) with respect to the adjacent coastal waters indicating that inputs from sewage, agricultural runoff and benthic fluxes were not fully assimilated within the lagoon. Tidal flushing was insufficient in the inner areas of the lagoon to remove or effectively dilute these inputs. Enrichment was most severe close to the urban centres of Faro and Olhão, as well as in the Gilão Estuary and the shallow extremities. Dissolved oxygen undersaturation (mean 75% during daylight hours) was associated with the area close to the sewage outlets of Faro. In the shallow west end of the lagoon during summer, dissolved oxygen supersaturation reached 140% during the day but fell to 50% at night. Classification using the EEA (2001) guidelines suggests the system is "poor" or "bad" with respect to phosphate concentrations for the majority of the year and "poor" in nitrogen contamination during the autumn rainy period. Due to the high overall nitrogen load in the lagoon, there is a net export to the coastal waters, especially during November and December, and phosphate only becomes limiting briefly during the spring bloom (April). Therefore, substantial phytoplankton populations may be supported year-round in the lagoon. The consequences of water quality deterioration in the Ria Formosa would negatively affect the lagoon as a regional resource, important for its ecological, economic and recreational value. The industries most affected would be tourism, fisheries and aquaculture. Management options include Urban Waste Water Treatment, dredging, artificial inlets, limits on urban development and changes in agricultural practices.

CISOCUR - Residence time modelling in the Curonian Lagoon and validation through stable isotope measurements

NASA Astrophysics Data System (ADS)

Umgiesser, Georg; Razinkovas-Baziukas, Arturas; Zemlys, Petras; Ertürk, Ali; Mėžinė, Jovita

2015-04-01

The spatial pattern of the hydrodynamic circulation of the Curonian lagoon, the largest European coastal lagoon, is still little understood. In absence of automatic current registration data all the existing models relied mostly on such data as water levels leaving high level of uncertainty. Here we present CISOCUR, a new project financed by European Social Fund under the Global Grant measure. The project applies a new methodology that uses the carbon stable isotope (SI) ratio of C12 and C13 that characterize different water sources entering the lagoon and may be altered by internal kinetic processes. Through the tracing of these isotope ratios different water masses can be identified. This gives the possibility to validate several hypotheses of water circulation and validate hydrodynamic models. In particular it will be possible to 1) trace water masses entering the lagoon through the Nemunas and the Klaipeda strait; 2) test the hypothesis of sediment transport mechanisms inside the lagoon; 3) evaluate the importance of physical forcing on the lagoon circulation. The use of a hydrodynamic finite element model, coupled with the SI method, will allow for a realistic description of the transport processes inside the Curonian lagoon. So the main research goal is to apply the stable isotope tracers and a finite element model to determine the circulation patterns in the Curonian lagoon. Here we show how the SI analysis was used to validate the hydrodynamic model on the basis of residence time. The average residence time of the Nemunas waters is estimated through SI data and is then compared with the model data computed through standard algorithms. Seasonal changes of carbon content are taken care of through a preliminary application of a carbon kinetic model. The results are compared to literature data.

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 (CH 4 ) 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 CH 4 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 CH 4 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 CH 4 oxidation potential with depth. An increase in CH 4 removal rates was observed among all columns over the 500 day incubation period, with steady-state CH 4 removal efficiencies ranging from ∼60 to 90% in the final stages of incubation (inlet load ∼80 g CH 4  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 CH 4 oxidation rates in terminal assays as the 2% uncharred wood pellet amendment. CH 4 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 CH 4

Phosphorus recovery from anaerobic swine lagoon sludge using the quick wash process

USDA-ARS?s Scientific Manuscript database

Long term accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed using pumping dredges. The dredged sludge is then land applied at agronomic rates according to its nutrient content. The accumul...

Phosphorus recovery from anaerobic swine lagoon sludge using the quick wash process

USDA-ARS?s Scientific Manuscript database

Long term and significant accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed by dredging. The dredged sludge is then land applied at agronomic rates according to its nutrient content. Becau...

Brominated Flame Retardants in Sediments of Four Coastal Lagoons of Yucatan, Mexico.

PubMed

Valenzuela-Sánchez, I S; Gold-Bouchot, G; Hernández-Núñez, E; Barrientos-Medina, R C; Garza-Gisholt, E; Zapata-Pérez, O

2018-05-02

We examined the sediments of four coastal lagoons (Ria Lagartos, Bocas de Dzilam, Laguna de Chelem and Ria Celestun) from the state of Yucatan, Mexico, for three widely used commercial polybrominated diphenyl ethers formulations (penta-, octa- and deca-BDE). The most commonly found congeners in all four lagoons were BDEs 47, 99 and 100 (all in the penta-BDE formulation) and BDE209 (deca-BDE formulation). The greatest variety and highest concentrations of brominated flame retardants were found in Ria Lagartos, which also showed the highest BDE 100 concentration (24.129 ng/g). Hexabromocyclododecane was found in all lagoons, but at lower concentrations than those of the various polybrominated diphenyl ethers. Dispersal routes of these compounds are discussed, such as a ring of sinkholes (cenotes) adjacent to the lagoons. Moreover, electronic waste is a serious problem because municipal landfills have been the primary disposal method for these wastes and therefore represent a reservoir of brominated fire retardants.

Formation of methane and nitrous oxide in plants

NASA Astrophysics Data System (ADS)

Keppler, Frank; Lenhart, Katharina

2017-04-01

and mosses, so called cryptogamic covers, were recently identified to release substantial amounts of nitrous oxide (Lenhart et al. 2015). In this presentation we will give a brief overview of recent observations of aerobic methane formation and nitrous oxide emissions from terrestrial vegetation. Furthermore, we will present new results from laboratory incubation experiments that provide further insights into the formation of methane and nitrous oxide from plants. References: Bruhn, D. et al.: Leaf surface wax is a source of plant methane formation under UV radiation and in the presence of oxygen. Plant Biology 16, 512-516, 2014. Chang, C. et al.: Nitrous Oxide Emission through Plants. Soil Science Society of America Journal 62, 35-38, 1998. Dean, J. V., Harper, J. E.: Nitric oxide and nitrous oxide production by soybean and winged bean during the in vivo nitrate reductase assay. Plant Physiology 82, 718-723, 1986. Keppler, F., Boros, M., Frankenberg, C., Lelieveld, J., McLeod, A., Pirttilä, A. M., Röckmann, T., Schnitzler, J.: Methane formation in aerobic environments, Environmental Chemistry, 6, 459-465, 2009. Lenhart, K. et al.: Nitrous oxide and methane emissions from cryptogamic covers. Global Change Biology 21, 3889-3900, 2015. Pihlatie, M., Ambus, P., Rinne, J., Pilegaard, K., Vesala, T.: Plant-mediated nitrous oxide emissions from beech (Fagus sylvatica) leaves. New Phytologist 168, 93-98, 2005. Wang, Z.-P., Chang, S. X., Chen, H., Han, X.-G.: Widespread non-microbial methane production by organic compounds and the impact of environmental stresses, Earth-Science Reviews, 127, 193-202, 2013.

Nutrient budgets and trophic state in a hypersaline coastal lagoon: Lagoa de Araruama, Brazil

NASA Astrophysics Data System (ADS)

Souza, Marcelo F. L.; Kjerfve, Björn; Knoppers, Bastiaan; Landim de Souza, Weber F.; Damasceno, Raimundo N.

2003-08-01

Lagoa de Araruama in the state of Rio de Janeiro, Brazil, is a hypersaline lagoon with salinity varying spatially from 45 to 56. We collected water samples during monthly cruises throughout the lagoon, and along the streams feeding the system, from April 1991 to March 1992. Nutrients and other water quality parameters exhibited great spatial and temporal variations. Mass balance calculations indicate large amounts of anthropogenic nutrient inputs. The data indicate that the lagoon currently is oligotrophic but is in a state of transition to become a mesotrophic system. Molar dissolved inorganic nitrogen:dissolved inorganic phosphorus (DIN/DIP) varied between 2.2:1 and 659:1 with a volume-weighted average of 22:1. The high DIN/DIP ratio contrasts with that found in nearby lagoons, suggesting that phytoplankton primary production is limited by phosphorus in Lagoa de Araruama. The major loss of DIP is apparently driven by biological assimilation and diagenic reactions in the sediments. Calculations indicate that the lagoon is slightly net autotrophic at +0.9 mol C m -2 yr -1. This suggests that the biomass of the primary producers is restricted by phosphorus availability. Phosphorus retention in the sediment and the hypersaline state of the lagoon prevent changes in autotrophic communities and the formation of eutrophic conditions.

Formation and retention of methane in coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 seamsmore » 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.« less

Groundwater dependence of coastal lagoons: The case of La Pletera salt marshes (NE Catalonia)

NASA Astrophysics Data System (ADS)

Menció, A.; Casamitjana, X.; Mas-Pla, J.; Coll, N.; Compte, J.; Martinoy, M.; Pascual, J.; Quintana, X. D.

2017-09-01

Coastal wetlands are among the most productive ecosystems of the world, playing an important role in coastal defense and wildlife conservation. These ecosystems, however, are usually affected by human activities, which may cause a loss and degradation of their ecological status, a decline of their biodiversity, an alteration of their ecological functioning, and a limitation of their ecosystem services. La Pletera salt marshes (NE Spain) are located in a region mainly dominated by agriculture and tourism activities. Part of these wetlands and lagoons has been affected by an incomplete construction of an urban development and in this moment is the focus of a Life+ project, whose aim is to restore this protected area. Several studies have analyzed the role of hydrological regime in nutrients, phytoplankton and zooplankton in this area, however, the role of groundwater was never considered as a relevant factor in the lagoon dynamics, and its influence is still unknown. In this study, the hydrogeological dynamics in La Pletera salt marshes has been analyzed, as a basis to set sustainable management guidelines for this area. In order to determine their dependence on groundwater resources, monthly hydrochemical (with major ions and nutrients) and isotopic (δ18OH2O and δD) campaigns have been conducted, from November 2014 to October 2015. In particular, groundwater from six wells, surface water from two nearby streams and three permanent lagoons, and sea water was considered in these surveys. Taking into account the meteorological data and the water levels in the lagoons, the General Lake Model has been conducted to determine, not only evaporation and rainfall occurring in the lagoons, but also the total inflows and outflows. In addition, the Gonfiantini isotopic model, together with equilibrium chemical-speciation/mass transfer models, has been used to analyze the evaporation and the physicochemical processes affecting the lagoons. Results show that during the dry

Risk Assessment for the Explosive Washout Lagoons (Site 4), Umatilla Depot Activity Hermiston, Oregon

DTIC Science & Technology

1992-03-01

Activity .............................. 2 2-2 Explosive Washout Lagoons (Site 4) and Washout Plant Area ............................... 2-3 3-1 Site 4...ponds for liquid wastes from bomb-washing operations in the washout plant . The measured dimensions of the flat bottoms of the two lagoons are 30 by 80...explosives washout plant system was drained, flushed, and cleaned approximately once each week from the mid-1950s until 1965. The lagoons received all of the

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

MethaneSat: Detecting Methane Emissions in the Barnett Shale Region

NASA Astrophysics Data System (ADS)

Propp, A. M.; Benmergui, J. S.; Turner, A. J.; Wofsy, S. C.

2017-12-01

In this study, we investigate the new information that will be provided by MethaneSat, a proposed satellite that will measure the total column dry-air mole fraction of methane at 1x1 km or 2x2 km spatial resolution with 0.1-0.2% random error. We run an atmospheric model to simulate MethaneSat's ability to characterize methane emissions from the Barnett Shale, a natural gas province in Texas. For comparison, we perform observation system simulation experiments (OSSEs) for MethaneSat, the National Oceanic and Atmospheric administration (NOAA) surface and aircraft network, and Greenhouse Gases Observing Satellite (GOSAT). The results demonstrate the added benefit that MethaneSat would provide in our efforts to monitor and report methane emissions. We find that MethaneSat successfully quantifies total methane emissions in the region, as well as their spatial distribution and steep gradients. Under the same test conditions, both the NOAA network and GOSAT fail to capture this information. Furthermore, we find that the results for MethaneSat depend far less on the prior emission estimate than do those for the other observing systems, demonstrating the benefit of high sampling density. The results suggest that MethaneSat would be an incredibly useful tool for obtaining detailed methane emission information from oil and gas provinces around the world.

Identity of active methanotrophs in landfill cover soil as revealed by DNA-stable isotope probing.

PubMed

Cébron, Aurélie; Bodrossy, Levente; Chen, Yin; Singer, Andrew C; Thompson, Ian P; Prosser, James I; Murrell, J Colin

2007-10-01

A considerable amount of methane produced during decomposition of landfill waste can be oxidized in landfill cover soil by methane-oxidizing bacteria (methanotrophs) thus reducing greenhouse gas emissions to the atmosphere. The identity of active methanotrophs in Roscommon landfill cover soil, a slightly acidic peat soil, was assessed by DNA-stable isotope probing (SIP). Landfill cover soil slurries were incubated with (13)C-labelled methane and under either nutrient-rich nitrate mineral salt medium or water. The identity of active methanotrophs was revealed by analysis of (13)C-labelled DNA fractions. The diversity of functional genes (pmoA and mmoX) and 16S rRNA genes was analyzed using clone libraries, microarrays and denaturing gradient gel electrophoresis. 16S rRNA gene analysis revealed that the cover soil was mainly dominated by Type II methanotrophs closely related to the genera Methylocella and Methylocapsa and to Methylocystis species. These results were supported by analysis of mmoX genes in (13)C-DNA. Analysis of pmoA gene diversity indicated that a significant proportion of active bacteria were also closely related to the Type I methanotrophs, Methylobacter and Methylomonas species. Environmental conditions in the slightly acidic peat soil from Roscommon landfill cover allow establishment of both Type I and Type II methanotrophs.

Socio-economic appraisal of fishing community in Pulicat lagoon, south east coast of India: case study.

PubMed

Devi, V Vandhana; Krishnaveni, M

2012-10-01

Assessment of socio-economic issues of fishing community is an important aspect in framing a strategy for the preservation of eco-systems which leads to sustainable lagoon management. The present investigation analyses the current potential socio-economic status of the fishing community of Pulicat lagoon, the second largest lagoon in India. The socio-economic indicators considered in the study include demography, economic aspects, social aspects and occupation details. The relevant details were collected from 300 fisher folk family by conducting field survey through a well prepared questionnaire in the villages around Pulicat lagoon. The data analysis was done using Statistical Program for Social Sciences (SPSS) to assess the adequacy and precision of the collected data. The important and encouraging socio-economic indicators identified from the field survey for effective lagoon management includes significant presence of younger generation in the region; affinity and self-belongingness of fisher folk towards the lake; better economic status and moderate education level; appreciable fishing income and affinity towards fishing profession. It is emphasized to motivate the fisher folk to improve their work attitude for betterment in economic status. The pertinent lagoon issues, comprising seasonal variation, local fishing issues, pollution from industries, water intake to thermal power plant which directly or indirectly affects the socio-economic status of fishing community, also need much emphasis while proposing sustainable lagoon management system. The information and observation from this study will be very helpful in formulating management policies on the conservation of the Pulicat lagoon ecosystem.

The atypical hydrodynamics of the Mayotte Lagoon (Indian Ocean): Effects on water age and potential impact on plankton productivity

NASA Astrophysics Data System (ADS)

Chevalier, C.; Devenon, J. L.; Pagano, M.; Rougier, G.; Blanchot, J.; Arfi, R.

2017-09-01

In mesotidal lagoons of the Indian Ocean, the coral reef barrier may be temporarily submerged at high tide and partially exposed at low tide, and this may cause unusual lagoon dynamics. A field measurement campaign was conducted in the north-east Mayotte Lagoon in order to understand these processes. An experimental approach was used, combining measurements taken by 1) a side-mounted Acoustic Doppler Current Profiler (ADCP) on a moving boat along transects through the reef passages (17 transects) and 2) by more conventional high-resolution moored ADCP measurements. A specific tidal analysis methodology was used to determine the spatial variability of the velocity. The tidal hydrodynamics within the lagoon were determined using a numerical model and then analyzed. The tide acted as a quasi-progressive forced wave in the lagoon: at low tide, water entered through the south passage, over the reef and left the lagoon through the north passage. This flow was reversed at high tide. The tide-driven quasi-progressive wave created a specific lagoon dynamics. Contrary to most other channel lagoons, the flow over the reef was mainly outward. This increases the inflow through the passages, which renews the water in the lagoon as shown by the indicators of age and origin of the water inside the lagoon. This study also showed the importance of these indicators for better understanding the variations and levels of plankton biomass (with chlorophyll concentration as proxy) which is quite high in this lagoon.

Groundwater and porewater as major sources of alkalinity to a fringing coral reef lagoon (Muri Lagoon, Cook Islands)

NASA Astrophysics Data System (ADS)

Cyronak, T.; Santos, I. R.; Erler, D. V.; Eyre, B. D.

2013-04-01

To better predict how ocean acidification will affect coral reefs, it is important to understand how biogeochemical cycles on reefs alter carbonate chemistry over various temporal and spatial scales. This study quantifies the contribution of shallow porewater exchange (as quantified from advective chamber incubations) and fresh groundwater discharge (as traced by 222Rn) to total alkalinity (TA) dynamics on a fringing coral reef lagoon along the southern Pacific island of Rarotonga over a tidal and diel cycle. Benthic alkalinity fluxes were affected by the advective circulation of water through permeable sediments, with net daily flux rates of carbonate alkalinity ranging from -1.55 to 7.76 mmol m-2 d-1, depending on the advection rate. Submarine groundwater discharge (SGD) was a source of TA to the lagoon, with the highest flux rates measured at low tide, and an average daily TA flux of 1080 mmol m-2 d-1 at the sampling site. Both sources of TA were important on a reef-wide basis, although SGD acted solely as a delivery mechanism of TA to the lagoon, while porewater advection was either a sink or source of TA dependent on the time of day. This study describes overlooked sources of TA to coral reef ecosystems that can potentially alter water column carbonate chemistry. We suggest that porewater and groundwater fluxes of TA should be taken into account in ocean acidification models in order to properly address changing carbonate chemistry within coral reef ecosystems.

Evidence of North Africa’s Green Revolution Preserved in Sedimentary Organic Matter Deposited in Three Coastal Lagoons.

EPA Science Inventory

Because of longer residence times and limited mixing in coastal lagoons, the impacts of anthropogenic nutrient loading to lagoon food webs are often more pronounced than in other coastal ecosystems. For these reasons, many lagoons also provide an excellent environment for the dep...

Decline of phosphorus, copper, and zinc in anaerobic lagoon columns receiving pretreated influent

USDA-ARS?s Scientific Manuscript database

Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. These lagoons usually require a sludge management plan for their maintenance consisting of regular sludge removal by mechanical agitation and pumping followed by land application at agr...

The role of benthic macrophytes and their associated macroinvertebrate community in coastal lagoon resistance to eutrophication.

PubMed

Lloret, Javier; Marín, Arnaldo

2009-12-01

Eutrophication is widely recognised as one of the major menaces to coastal environments, particularly enclosed bays and lagoons. Although there is a general understanding of the consequences of eutrophication in these systems, there is a lack of sufficient knowledge concerning biotic feedbacks that influence eutrophication patterns and the resistance capacity of coastal environments. In this paper, the isotope ratios of main producers and consumers of a Mediterranean lagoon were examined in order to elucidate the fate of anthropogenic inputs from the main watercourse flowing into the lagoon. The results of the study of stable isotope data in the Mar Menor lagoon reflected that the whole benthic community plays an important role as a natural 'filter' that removes excess nutrients from the water column and stores them in the sediments, thereby enhancing lagoon resistance to eutrophication.

Living in a coastal lagoon environment: photosynthetic and biochemical mechanisms of key marine macroalgae.

PubMed

García-Sánchez, Marta; Korbee, Nathalie; Pérez-Ruzafa, Isabel María; Marcos, Concepción; Figueroa, Félix L; Pérez-Ruzafa, Ángel

2014-10-01

The physiological status of Cystoseira compressa, Padina pavonica and Palisada tenerrima was studied by in vivo chlorophyll fluorescence, pigment content, stoichiometry (C:N), accumulation of UV photoprotectors and antioxidant activity; comparing their photosynthetic response in a coastal lagoon (Mar Menor) and in Mediterranean coastal waters. In general, the specimens reached their highest ETRmax in spring in the Lagoon, but in summer in the Mediterranean, coinciding with their maximum biomass peak. The species exhibited a dynamic photoinhibition. Except C. compressa, they showed a lower decrease in Fv/Fm and higher recovery rates in the Mediterranean populations when exposed to high irradiance. The higher salinity and temperature of the lagoon could impair the photoprotection mechanisms. The acclimation to lagoon environments is species-specific and involves complex regulatory mechanisms. The results underline the importance of N in repair, avoidance, quenching and scavenging mechanisms. In general, Lagoon specimens showed higher pigment concentration. Although xanthophylls play important photo-protective and antioxidant roles, the observed trend is more likely to be explained by the higher temperatures reached in the lagoon compared to Mediterranean. Therefore the studied photosynthetic and biochemical mechanisms can be effective not only for high irradiance, but also for higher temperatures in a climate change scenario, but are highly dependent on nutrient availability. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Bayesian Network Model for Assessing Estrogen Fate and Transport in a Swine Waste Lagoon

PubMed Central

Lee, Boknam; Kullman, Seth W.; Yost, Erin; Meyer, Michael T.; Worley-Davis, Lynn; Reckhow, Kenneth H.

2017-01-01

Commercial swine waste lagoons are regarded as a major reservoir of natural estrogens, which have the potential to produce adverse physiological effects on exposed aquatic organisms and wildlife. However, there remains limited understanding of the complex mechanisms of physical, chemical, and biological processes that govern the fate and transport of natural estrogens within an anaerobic swine lagoon. To improve lagoon management and ultimately help control the offsite transport of these compounds from swine operations, a Bayesian network model was developed to predict estrogen fate and budget and compared against data collected from a commercial swine field site. In general, the model was able to predict the estrogen fate and budget in both the slurry and sludge stores within the swine lagoon. Sensitivity analysis within the model, demonstrated that the estrogen input loading from the associated barn facility was the most important factor in controlling estrogen concentrations within the lagoon slurry storage, while the settling rate was the most significant factor in the lagoon sludge storage. The degradation reactions were shown to be minor in both stores based on prediction of average total estrogen concentrations. Management scenario evaluations showed that the best possible management options to reduce estrogen levels in the lagoon are either to adjust the estrogen input loading from swine barn facilities or to effectively enhancing estrogen bonding with suspended solids through the use of organic polymers or inorganic coagulants. PMID:24798317

Sources and Fluxes of Atmospheric Methane from Lakes in the Alaskan Arctic

NASA Astrophysics Data System (ADS)

Townsend-Small, A.; Akerstrom, F.; Hinkel, K. M.; Arp, C. D.; Beck, R. A.; Grosse, G.; Jones, B. M.; Kim, C.; Lenters, J. D.; Liu, H.; Eisner, W. R.

2014-12-01

Climate warming in the Arctic may result in release of carbon dioxide and/or methane from thawing permafrost soils, resulting in a positive feedback to warming. Permafrost thaw may also result in release of methane from previously trapped natural gas. The Arctic landscape is approximately 50% covered by shallow permafrost lakes, and these environments may serve as bellwethers for climate change - carbon cycle feedbacks, since permafrost thaw is generally deeper under lakes than tundra soils. Since 2011, the Circum-Arctic Lakes Observation Network (CALON) project has documented landscape-scale variability in physical and biogeochemical processes of Arctic lakes in permafrost terrain, including carbon cycle feedbacks to climate warming. Here we present a dataset of concentrations, isotope ratios (13C and 2H), and atmospheric fluxes of methane from lakes in Arctic Alaska. Concentrations of methane in lake water ranged from 0.3 to 43 micrograms per liter, or between 6 and 750 times supersaturated with respect to air. Isotopic measurements of dissolved methane indicated that most of the lakes had methane derived from anaerobic organic matter decomposition, but that some lakes may have a small source of methane from fossil fuel sources such as natural gas or coal beds. Concurrent measurements of methane fluxes and dissolved methane concentrations in summer of 2014 will aid in translating routine dissolved measurements into fluxes, and will also elucidate the relative importance of diffusive versus ebulliative fluxes. It is essential that measurements of methane emissions from Arctic lakes be continued long-term to determine whether methane emissions are on the rise, and whether warming of the lakes leads to increased venting of fossil fuel methane from enhanced thaw of permafrost beneath the lakes.

Fingerprints of lagoonal life: Migration of the marine flatfish Solea solea assessed by stable isotopes and otolith microchemistry

NASA Astrophysics Data System (ADS)

Dierking, Jan; Morat, Fabien; Letourneur, Yves; Harmelin-Vivien, Mireille

2012-06-01

The commercially important marine flatfish common sole (Solea solea) facultatively uses NW Mediterranean lagoons as nurseries. To assess the imprint left by the lagoonal passage, muscle carbon (C) and nitrogen (N) isotope values of S. solea juveniles caught in Mauguio lagoon in spring (shortly after arrival from the sea) and in autumn (before the return to the sea) were compared with values of juveniles from adjacent coastal marine nurseries. In addition, in the lagoon, sole otolith stable isotope (C and oxygen (O)) and elemental (11 elements) composition in spring and autumn, and the stable isotope composition (C and N) of organic matter sources in autumn, were determined. Overall, our data indicate that a distinct lagoonal signature existed. Specifically, lagoon soles showed a strong enrichment in muscle tissue 15N (>6‰) compared to their coastal relatives, likely linked to sewage inputs (see below), and a depletion in 13C (1-2‰), indicative of higher importance of 13C depleted terrestrial POM in the lagoon compared to coastal nurseries. In addition, over the time spent in the lagoon, sole otolith δ13C and δ18O values and otolith elemental composition changed significantly. Analysis of the lagoon sole foodweb based on C and N isotopes placed sediment particulate organic matter (POM) at the base. Seagrasses, formerly common but in decline in Mauguio lagoon, played a minor role in the detritus cycle. The very strong 15N enrichment of the entire foodweb (+7 to +11‰) compared to little impacted lagoons and coastal areas testified of important human sewage inputs. Regarding the S. solea migration, the analysis of higher turnover and fast growth muscle tissue and metabolically inert and slower growth otoliths indicated that soles arrived at least several weeks prior to capture in spring, and that no migrations took place in summer. In the autumn, the high muscle δ15N value acquired in Mauguio lagoon would be a good marker of recent return to the sea, whereas

Biodiversity patterns of macrophyte and macroinvertebrate communities in two lagoons of Western Greece.

NASA Astrophysics Data System (ADS)

Fyttis, G.; Reizopoulou, S.; Papastergiadou, E.

2012-04-01

Aquatic macrophytes and benthic macroinvertebrates were studied seasonally (Spring, Autumn, Summer) between the years 2009 - 2011 in two coastal lagoons (Kotychi and Prokopos) located in Peloponnese, Greece, in order to investigate spatial and temporal biodiversity trends related to hydrological processes (degree of confinement, nitrates, phosphates, chl-a, total suspended materials, light irradiance, pH, salinity, temperature and dissolved oxygen). Kotychi lagoon presents a better communication with the sea, while Prokopos has a high degree of confinement. Both ecosystems seasonally receive freshwater input from streams. The submerged aquatic macrophytes constituted a major component of the ecosystems studied. In total, 22 taxa of aquatic macrophytes (angiosperms and macroalgae), 16 taxa for Kotychi (2 Rhodophyta, 8 Chlorophyta, 5 Magnoliophyta, 1 Streptophyta) and 14 taxa for Prokopos (1 Rhodophyta, 5 Chlorophyta, 5 Magnoliophyta, 3 Streptophyta) were found. Ruppia cirrhosa, and Potamogeton pectinatus were dominant in both lagoons. Kotychi lagoon was also dominated by Zostera noltii and Prokopos by Zannichellia pallustris ssp. pedicellata, while the biomass of aquatic species peaked during the summer periods, in both lagoons. The total number of macroinvertebrates found in the lagoons was 28 taxa for Kotychi and 19 for Prokopos. Chironomidae were dominant in both lagoons, while Kotychi was also dominated by Lekanesphaera monodi and Monocorophium insidiosum, and Prokopos by Ostracoda and Lekanesphaera monodi. Benthic diversity ranged from 1.33 to 2.57 in Kotychi and from 0.67 to 2.48 in Prokopos. Species richness, diversity, and abundance of benthic macroinvertebrates were strongly related to aquatic vegetation and to the degree of communication with the marine environment. Moreover, species richness and abundance of both macrophytes and macroinvertebrates were mainly dependent on depth, temperature, pH and concentration of total suspended materials (TSM). Results

Observations of emperor geese feeding at Nelson Lagoon, Alaska

USGS Publications Warehouse

Petersen, Margaret R.

1983-01-01

Estuaries along the north side of the Alaska Peninsula provide essential habitat for most of the American population of Emperor Goose (Chen canagica) during migration (Petersen and Gill 1982). Most of the population passes through Nelson Lagoon in spring and fall, with over 40,000 birds recorded there (Gill et al 1981). Little is known about the feeding activity of Emperor Geese while they are in estuaries, and the importance of estuaries as staging areas during spring and fall migration is poorly understood. Here I report observations on the feeding activity of emperor Geese at one estuary (Nelson Lagoon).

Methane Recycling During Burial of Methane Hydrate-Bearing Sediments

NASA Astrophysics Data System (ADS)

You, K.; Flemings, P. B.

2017-12-01

We quantitatively investigate the integral processes of methane hydrate formation from local microbial methane generation, burial of methane hydrate with sedimentation, and methane recycling at the base of the hydrate stability zone (BHSZ) with a multiphase multicomponent numerical model. Methane recycling happens in cycles, and there is not a steady state. Each cycle starts with free gas accumulation from hydrate dissociation below the BHSZ. This free gas flows upward under buoyancy, elevates the hydrate saturation and capillary entry pressure at the BHSZ, and this prevents more free gas flowing in. Later as this layer with elevated hydrate saturation is buried and dissociated, the large amount of free gas newly released and accumulated below rapidly intrudes into the hydrate stability zone, drives rapid hydrate formation and creates three-phase (gas, liquid and hydrate) equilibrium above the BHSZ. The gas front retreats to below the BHSZ until all the free gas is depleted. The shallowest depth that the free gas reaches in one cycle moves toward seafloor as more and more methane is accumulated to the BHSZ with time. More methane is stored above the BHSZ in the form of concentrated hydrate in sediments with relatively uniform pore throat, and/or with greater compressibility. It is more difficult to initiate methane recycling in passive continental margins where the sedimentation rate is low, and in sediments with low organic matter content and/or methanogenesis reaction rate. The presence of a permeable layer can store methane for significant periods of time without recycling. In a 2D system where the seafloor dips rapidly, the updip gas flow along the BHSZ transports more methane toward topographic highs where methane gas and elevated hydrate saturation intrude deeper into the hydrate stability zone within one cycle. This could lead to intermittent gas venting at seafloor at the topographic highs. This study provides insights on many phenomenon associated with

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.

Parasite communities of the neotropical cormorant Phalacrocorax brasilianus (Gmelin) (Aves, Phalacrocoracidae) from two coastal lagoons in Guerrero state, Mexico.

PubMed

Violante-González, Juan; Monks, Scott; Gil-Guerrero, Salvador; Rojas-Herrera, Agustín; Flores-Garza, Rafael; Larumbe-Morán, Edvino

2011-11-01

The parasite community structure of the neotropical cormorant, Phalacrocorax brasilianus, from two lagoons (Coyuca and Tres Palos) from Guerrero state, México, was examined. Fourteen species of adult helminths (6,391 individuals) from 48 cormorants were identified: 9 digeneans, 1 acanthocephalan, 1 cestode, and 3 nematodes. A total of 11 species were collected in Coyuca Lagoon and 12 in Tres Palos Lagoon. Nine species co-occurred in cormorants of both lagoons but, with the exception of Contracaecum multipapillatum and Drepanocephalus olivaceus, species were not equally common in both lagoons. The prevalence values of six species of helminth and the mean abundance of four species varied significantly between lagoons, and C. multipapillatum was numerically dominant in both lagoons. The qualitative similarity between the two communities at the component level was 64%. All cormorants examined were infected, and parasite species richness was 3-5 in Coyuca and 4-9 in Tres Palos lagoon. The results indicate that both communities presented a similar structure at the component level, probably because the cormorants of both lagoons feed on the same species of fish and thus acquire almost the same species of parasites. Differences observed at the infracommunity level were attributed to variations in the degree of dominance of the particular species.

Flushing of a polluted lagoon in Canc'un, using a SIBEO wave-driven seawater pump

NASA Astrophysics Data System (ADS)

Czitrom, Steven; Carbajal, Noel

2006-11-01

The coastal lagoon which adorns the seaside resort at Canc'un, Mexico, is heavily polluted as a result of decades of intense tourist activity development and overwhelmed inadequate planning. The natural flushing time of the lagoon, estimated at 2 to 4 years, is insufficient to cope with the waste that is being dumped and a thick layer of organic matter has accumulated on the lagoon bed. Appropriate legal and sewage treatment measures are imperative to curb further dumping and thus attack the root cause of the problem. This aside, however, the existing situation requires additional technical solutions to restore the ecosystem to a less altered state. A wave and tide driven seawater pump, invented and developed at the National University of Mexico, has been proposed to flush the lagoon with an average 0.2 m^3/s of clean and oxygen rich seawater from the neighboring ocean. This flow would reduce the residence time of the lagoon to around 6 months, promoting long term recovery of the ecosystem. The effect and distribution of the pumped water is being studied using a wind and tide driven 3D numerical model of the lagoon hydrodynamics. Some results from this study are presented here.

Sludge reduction and water quality improvement in anaerobic lagoons through influent pre-treatment

USDA-ARS?s Scientific Manuscript database

Confined swine production generates large volumes of wastewater typically stored and treated in anaerobic lagoons. These lagoons may require cleanup and closure measures in the future. In practice, liquid and sludge need to be removed by pumping, usually at great expense of energy, and land applied ...

Developing a model for the mercury cycle in the Marano-Grado Lagoon (Italy)

EPA Science Inventory

The Marano-Grado Lagoon is a wetland system of about 160 km2 located in the Northern Adriatic Sea (Italy) between the Tagliamento and the Isonzo River mouths. The lagoon morphology and biogeochemistry are primarily controlled by the exchange with the Adriatic Sea and, to a lesser...

The role of connectivity and hydrodynamic conditions in the configuration of ichthyoplankton assemblages in coastal lagoons

NASA Astrophysics Data System (ADS)

Pérez-Ruzafa, Angel; Quispe, Jhoni I.; Umgiesser, Georg; Ghezzo, Michol; De Pascalis, Francesca; Marcos, Concepción

2014-05-01

Fish assemblages in coastal lagoons are constituted by species with different gilds and life stories including estuarine residents but also a high percentage of marine stragglers and marine migrants. Previous studies showed that different ichthyoplancton assemblages can be identified inside a lagoon, depending on hydrological conditions, but at the same time a high spatial and temporal variability haven observed. The proposed models to explain lagoon assemblages configuration based on probabilities of colonization from the open sea involves an important stochastic component and introduces some randomness that could lead to that high spatial and temporal variability at short and long-term scales. In this work we analyze the relationship between ichthyoplankton assemblages in the Mar Menor lagoon and the adjacent open sea in the framework of the hydrodynamics of the lagoon and connectivity between sampling stations using hydrodynamic models. The results, show a complex interaction between the different factors that lead to a highly variable system with high accumulated richness and diversity of species, and a large proportion of occasional visitors and stragglers suggesting that the mechanisms of competitive lottery can play an important role in the maintenance of communities of coastal lagoons , where environmental variability occurs in a system with strong differences in colonization rates and connectivity, not only with the open sea, but also between locations within the lagoon.

Hydrogen generator, via catalytic partial oxidation of methane for fuel cells

NASA Astrophysics Data System (ADS)

Recupero, Vincenzo; Pino, Lidia; Di Leonardo, Raffaele; Lagana', Massimo; Maggio, Gaetano

It is well known that the most acknowledged process for generation of hydrogen for fuel cells is based upon the steam reforming of methane or natural gas. A valid alternative could be a process based on partial oxidation of methane, since the process is mildly exothermic and therefore not energy intensive. Consequently, great interest is expected from conversion of methane into syngas, if an autothermal, low energy intensive, compact and reliable process could be developed. This paper covers the activities, performed by the CNR Institute of Transformation and Storage of Energy (CNR-TAE), on theoretical and experimental studies for a compact hydrogen generator, via catalytic selective partial oxidation of methane, integrated with second generation fuel cells (EC-JOU2 contract). In particular, the project focuses the attention on methane partial oxidation via heterogeneous selective catalysts, in order to: demonstrate the basic catalytic selective partial oxidation of methane (CSPOM) technology in a subscale prototype, equivalent to a nominal output of 5 kWe; develop the CSPOM technology for its application in electric energy production by means of fuel cells; assess, by a balance of plant analysis, and a techno-economic evaluation, the potential benefits of the CSPOM for different categories of fuel cells.

CISOCUR - Hydrodynamic circulation in the Curonian Lagoon inferred through stable isotope measurements and numerical modelling

NASA Astrophysics Data System (ADS)

Umgiesser, Georg; Razinkovas-Baziukas, Arturas; Barisevičiūtė, Ruta; Baziukė, Dalia; Ertürk, Ali; Gasiūnaitė, Jovita; Gulbinskas, Saulius; Lubienė, Irma; Maračkinaite, Jurgita; Petkuvienė, Jolita; Pilkaitytė, Renata; Ruginis, Tomas; Zemlys, Petras; Žilius, Mindaugas

2013-04-01

The spatial pattern of the hydrodynamic circulation of the Curonian lagoon, the largest European coastal lagoon, is still little understood. In absence of automatic current registration data all the existing models relied mostly on such data as water levels leaving high level of uncertainty. Here we present CISOCUR, a new project financed by the European Social Fund under the Global Grant measure. The project applies a new methodology that uses the carbon stable isotope (SI) ratio of C12 and C13 that characterize different water sources entering the lagoon and may be altered by internal kinetic processes. Through the tracing of these isotope ratios different water masses can be identified. This gives the possibility to validate several hypotheses of water circulation and validate hydrodynamic models. In particular it will be possible to 1) trace water masses entering the lagoon through the Nemunas and the Klaipeda strait; 2) test the hypothesis of sediment transport mechanisms inside the lagoon; 3) evaluate the importance of physical forcing on the lagoon circulation. The use of a hydrodynamic finite element model, coupled with the SI method, will allow for a realistic description of the transport processes inside the Curonian lagoon. So the main research goal is to apply the stable isotope tracers and a finite element model to determine the circulation patterns in the Curonian lagoon. Overall, the project will develop according to 4 main phases: 1) A pilot study to measure the isotope composition of different carbon compounds (dissolved and suspended) in different water bodies that feed water into the central lagoon. Through this pilot study the optimal study sites for the seasonal campaign will be identified as well. 2) Seasonal field campaigns in the monitoring stations identified in phase 1 to measure the carbon isotope ratio. 3) Development of a model that describes the kinetics of carbon isotopes and its transformation. 4) Application of a hydrodynamic model

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

Metazoan parasites of fishes from the Celestun coastal lagoon, Yucatan, Mexico.

PubMed

Sosa-Medina, Trinidad; Vidal-Martínez, Víctor M; Aguirre-Macedo, M Leopoldina

2015-08-31

The aims of this study were to produce a checklist of the metazoan parasites of fishes from the Celestun coastal lagoon and to determine the degree of faunal similarity among the fishes based on the metazoan parasites they share. A checklist was prepared including all available records (1996-2014) of parasites of marine, brackish water and freshwater fishes of the area. All of these data were included in a presence/absence database and used to determine similarity via Jaccard's index. The results indicate the presence of 62 metazoan parasite species infecting 22 fish species. The number of metazoan parasite species found in the fishes from the Celestún lagoon is apparently the highest reported worldwide for a tropical coastal lagoon. The parasites included 12 species of adult digeneans, 27 digeneans in the metacercarial stage, 6 monogeneans, 3 metacestodes, 9 nematodes, 2 acanthocephalans, 2 crustaceans and 1 annelid. Forty parasite species were autogenic and 23 were allogenic and 1 unknown. The overall similarity among all of the species of fish with respect to the metazoan parasites they share was low (0.08 ± 0.12), with few similarity values above 0.4 being obtained. This low similarity was due primarily to the presence of suites of parasites exclusive to specific species of fish. The autogenic component of the parasite fauna (40 species) dominated the allogenic component (21 species). The most likely explanation for the large number of fish parasites found at Celestún is the good environmental condition of the lagoon, which allows the completion of parasite life cycles and free circulation of euryhaline fishes from the marine environment bringing marine parasites into the lagoon.

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.

Tidal dynamics in a changing lagoon: Flooding or not flooding the marginal regions

NASA Astrophysics Data System (ADS)

Lopes, Carina L.; Dias, João M.

2015-12-01

Coastal lagoons are low-lying systems under permanent changes motivated by natural and anthropogenic factors. Ria de Aveiro is such an example with its margins currently threatened by the advance of the lagoonal waters recorded during the last decades. This work aims to study the tidal modifications found between 1987 and 2012 in this lagoon, motivated by the main channels deepening which induce higher inland tidal levels. Additionally it aims to study the impact that protective walls designed to protect the margins against flooding may have in those modifications under sea level rise predictions. The hydrodynamic model ELCIRC previously calibrated for Ria de Aveiro was used and tidal asymmetry, tidal ellipses and residual currents were analyzed for different scenarios, considering the mean sea level rise predicted for 2100 and the implementation of probable flood protection walls. Results evidenced that lagoon dominance remained unchanged between 1987 and 2012, but distortion decreased/increased in the deeper/shallower channels. The same trend was found under mean sea level rise conditions. Tidal currents increased over this period inducing an amplification of the water properties exchange within the lagoon, which will be stronger under mean sea level rise conditions. The deviations between scenarios with or without flood protection walls can achieve 60% for the tidal distortion and residual currents and 20% for the tidal currents, highlighting that tidal properties are extremely sensitive to the lagoon geometry. In summary, the development of numerical modelling applications dedicated to study the influence of mean sea level rise on coastal low-lying systems subjected to human influence should include structural measures designed for flood defence in order to accurately predict changes in the local tidal properties.

A Trophic Model of a Sandy Barrier Lagoon at Chiku in Southwestern Taiwan

NASA Astrophysics Data System (ADS)

Lin, H.-J.; Shao, K.-T.; Kuo, S.-R.; Hsieh, H.-L.; Wong, S.-L.; Chen, I.-M.; Lo, W.-T.; Hung, J.-J.

1999-05-01

Using the ECOPATH 3.0 software system, a balanced trophic model of a sandy barrier lagoon with intensive fishery activities at Chiku in tropical Taiwan was constructed. The lagoon model comprised 13 compartments. Trophic levels of the compartments varied from 1·0 for primary producers and detritus to 3·6 for piscivorous fish. Hanging-cultured oysters accounted for 39% of the harvestable fishery biomass and were the most important fishery species. The most prominent group in terms of biomass and energy flow in the lagoon was herbivorous zooplankton. Manipulations of the biomass of herbivorous zooplankton would have a marked impact on most compartments. Both total system throughput and fishery yield per unit area were high when compared to other reported marine ecosystems. This appears mainly due to high planktonic primary production, which is probably promoted by enriched river discharges draining mangroves and aquaculture ponds. Consequently, more than half of the total system throughput originates from primary producers in the lagoon. Although half of the primary production was not immediately used by upper trophic levels and flowed into the detrital pool, most of the detritus was directly consumed, passed up the food web and was exported to the fishery. Thus only a small proportion of energy was recycled through detritus pathways. This mechanism produces short pathways with high trophic efficiencies at higher trophic levels. The high fishery yield in the lagoon is due to high primary production and short pathways. This is the first model of a tropical sandy barrier lagoon with intensive fishery activities and thus may serve as a basis for future comparisons and ecosystem management.

Microbial Community Analysis of a Methane-Producing Biocathode in a Bioelectrochemical System

PubMed Central

Van Eerten-Jansen, Mieke C. A. A.; Veldhoen, Anna B.; Plugge, Caroline M.; Stams, Alfons J. M.; Buisman, Cees J. N.

2013-01-01

A methane-producing biocathode that converts CO2 into methane was studied electrochemically and microbiologically. The biocathode produced methane at a maximum rate of 5.1 L CH4/m2 projected cathode per day (1.6 A/m2) at −0.7 V versus NHE cathode potential and 3.0 L CH4/m2 projected cathode per day (0.9 A/m2) at −0.6 V versus NHE cathode potential. The microbial community at the biocathode was dominated by three phylotypes of Archaea and six phylotypes of bacteria. The Archaeal phylotypes were most closely related to Methanobacterium palustre and Methanobacterium aarhusense. Besides methanogenic Archaea, bacteria seemed to be associated with methane production, producing hydrogen as an intermediate. Biomass density varied greatly with part of the carbon electrode covered with a dense biofilm, while only clusters of cells were found on other parts. Based on our results, we discuss how inoculum enrichment and changing operational conditions may help to increase biomass density and to select for microorganisms that produce methane. PMID:24187516

Anaerobic Methane Oxidation in Soils - revealed using 13C-labelled methane tracers

NASA Astrophysics Data System (ADS)

Riekie, G. J.; Baggs, E. M.; Killham, K. S.; Smith, J. U.

2008-12-01

In marine sediments, anaerobic methane oxidation is a significant biogeochemical process limiting methane flux from ocean to atmosphere. To date, evidence for anaerobic methane oxidation in terrestrial environments has proved elusive, and its significance is uncertain. In this study, an isotope dilution method specifically designed to detect the process of anaerobic methane oxidation in methanogenic wetland soils is applied. Methane emissions of soils from three contrasting permanently waterlogged sites in Scotland are investigated in strictly anoxic microcosms to which 13C- labelled methane is added, and changes in the concentration and 12C/13C isotope ratios of methane and carbon dioxide are subsequently measured and used to calculate separate the separate components of the methane flux. The method used takes into account the 13C-methane associated with methanogenesis, and the amount of methane dissolved in the soil. The calculations make no prior assumptions about the kinetics of methane production or oxidation. The results indicate that methane oxidation can take place in anoxic soil environments. The clearest evidence for anaerobic methane oxidation is provided by soils from a minerotrophic fen site (pH 6.0) in Bin Forest underlain by ultra-basic and serpentine till. In the fresh soil anoxic microcosms, net consumption methane was observed, and the amount of headspace 13C-CO2 increased at a greater rate than the 12+13C-CO2, further proof of methane oxidation. A net increase in methane was measured in microcosms of soil from Murder Moss, an alkaline site, pH 6.5, with a strong calcareous influence. However, the 13C-CH4 data provided evidence of methane oxidation, both in the disappearance of C- CH4 and appearance of smaller quantities of 13C-CO2. The least alkaline (pH 5.5) microcosms, of Gateside Farm soil - a granitic till - exhibited net methanogenesis and the changes in 13C-CH4 and 13C-CO2 here followed the pattern expected if no methane is consumed

Biodegradation of hexadecane using sediments from rivers and lagoons of the Southern Gulf of Mexico.

PubMed

García-Cruz, N Ulises; Sánchez-Avila, Juan I; Valdés-Lozano, David; Gold-Bouchot, Gerardo; Aguirre-Macedo, Leopoldina

2018-03-01

The Southern Gulf of Mexico is an area highly impacted by crude oil extraction, refining activities and the presence of natural petroleum seepage. Oceanic currents in the Gulf of Mexico continually facilitate the transport of hydrocarbons to lagoons and rivers. This research evaluated hexadecane (HXD) degradation in marine sediment samples from lagoons and rivers that are fed by the Southern Gulf of Mexico, specifically six samples from rivers, three samples from lagoons, and one sample from a marine outfall. The highest rates of biodegradation were observed in sediments from the mouths of the Gonzalez River and the Champotón Lagoon. The lowest consumption rate was found in sediment from the mouth of the Coatzacoalcos River. With regards to the Ostión Lagoon and the Grijalva River, there was a low rate of consumption, but a high efficiency of degradation which took place at the end of the experiments. No correlation was found between the consumption rate and the environmental physicochemical parameters. Copyright © 2018 Elsevier Ltd. All rights reserved.

Meiobenthic communities in permanently open estuaries and open/closed coastal lagoons of Uruguay (Atlantic coast of South America)

NASA Astrophysics Data System (ADS)

Kandratavicius, N.; Muniz, P.; Venturini, N.; Giménez, L.

2015-09-01

This study aimed to determine if estuarine meiofaunal communities of Uruguay (South America) vary between permanently open estuaries and open/closed coastal lagoons, or if they respond to the sediment composition. In Uruguay, estuaries and coastal lagoons vary in the degree of connectivity to the sea and in the sediment composition; sediments in estuaries are characterized by fine-medium sands but sediments vary from lagoon to lagoon (either fine-medium or coarse sand). Taxa richness (total = 16) showed less temporal variability in lagoons than in estuaries, due to patterns of presence/absence of the less abundant taxa. However, no major response to habitat was found in the most abundant groups: polychaetes (6% of total fauna) were on average 5% more abundant in lagoons than in estuaries. Some level of zonation, within estuaries and lagoons, was found in the most abundant groups, nematodes (63% of total fauna) and copepods (15%) in response to medium and fine sands. In addition, sediment type modulated seasonal patterns in the frequency of presence/absence in ostracods, polychaetes and oligochaetes. For instance, in polychaetes and ostracods the increase in the frequency of absences, occurring from summer to winter, was stronger in lagoons and estuaries dominated by fine sands. The lagoon habitat appears to ameliorate the effects of unfavourable (winter) conditions in less abundant meiofaunal taxa. In summary, sediment fractions explain spatial patterns in the average abundance of organisms (e.g. nematodes) as well as the seasonal changes in frequency of presence/absence (e.g. polychaetes).

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. Copyright © 2015, American Association for the Advancement of Science.

Seasonal and Latitudinal Variations in Dissolved Methane from 42 Lakes along a North-South Transect in Alaska

NASA Astrophysics Data System (ADS)

Sepulveda-Jauregui, A.; Walter Anthony, K. M.; Martinez-Cruz, K. C.; Anthony, P.; Thalasso, F.

2013-12-01

Armando Sepulveda-Jauregui,* Katey M. Walter Anthony,* Karla Martinez-Cruz,* ** Peter Anthony,* and Frederic Thalasso**. * Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, Alaska. ** Biotechnology and Bioengineering Department, Cinvestav, Mexico city, D. F., Mexico. Northern lakes are important reservoirs and sources to the atmosphere of methane (CH4), a potent greenhouse gas. It is estimated that northern lakes (> 55 °N) contribute about 20% of the total global lake methane emissions, and that emissions from these lakes will increase with climate warming. Temperature rise enhances methane production directly by providing the kinetic energy to methanogenesis, and indirectly by supplying organic matter from thawing permafrost. Warmer lakes also store less methane since methane's solubility is inversely related to temperature. Alaskan lakes are located in three well-differentiated permafrost classes: yedoma permafrost with high labile carbon stocks, non-yedoma permafrost with lower carbon stocks, and areas without permafrost, also with generally lower carbon stocks. We sampled dissolved methane from 42 Alaskan lakes located in these permafrost cover classes along a north-south Alaska transect from Prudhoe Bay to the Kenai Peninsula during open-water conditions in summer 2011. We sampled 26 of these lakes in April, toward the end of the winter ice-covered period. Our results indicated that the largest dissolved methane concentrations occurred in interior Alaska thermokarst lakes formed in yedoma-type permafrost during winter and summer, with maximal concentrations of 17.19 and 12.76 mg L-1 respectively. In these lakes, emission of dissolved gases as diffusion during summer and storage release in spring were 18.4% and 17.4% of the annual emission budget, while ebullition (64.2 %) comprised the rest. Dissolved oxygen was inversely correlated with dissolved methane concentrations in both seasons; the

Spatial variation of acid-volatile sulfide and simultaneously extracted metals in Egyptian Mediterranean Sea lagoon sediments.

PubMed

Younis, Alaa M; El-Zokm, Gehan M; Okbah, Mohamed A

2014-06-01

In risk assessment of aquatic sediments, the immobilizing effect of acid-volatile sulfide (AVS) on trace metals is a principal control on availability and associated toxicity of metals to aquatic biota, which reduces metal bioavailability and toxicity by binding and immobilizing metals as insoluble sulfides. Spatial variation pattern of AVS, simultaneously extracted metals (SEM), and sediment characteristics were studied for the first time in surface sediment samples (0-20 cm) from 43 locations in Egyptian northern delta lagoons (Manzalah, Burullus, and Maryut) as predictors of the bioavailability of some divalent metals (Cu, Zn, Cd, Pb, and Ni) in sediments as well as indicators of metal toxicity in anaerobic sediments. The results indicated that the ∑SEM (Cu + Zn + Cd + Pb + Ni) values in sediments of lagoon Burullus had higher concentrations than those of Maryut and Manzalah. In contrast, AVS concentrations were considerably higher in lagoons Manzalah and Maryut and seemed to be consistent with the increase in organic matter than lagoon Burullus. Generally, the average concentrations of the SEM in all lagoons were in the order of Zn > Cu > Ni > Pb > Cd. The ratios of ∑SEM/AVS were less than 1 at all the sampling stations except at one station in lagoon Maryut as well as four stations located in lagoon Burullus (∑SEM/AVS > 1), which suggests that the metals have toxicity potential in these sediments. Therefore, SEM concentrations probably are better indicators of the metal bioavailability in sediments than the conventional total metal concentrations.

Vadose Zone Monitoring of Dairy Green Water Lagoons using Soil Solution Samplers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brainard, James R.; Coplen, Amy K

2005-11-01

Over the last decade, dairy farms in New Mexico have become an important component to the economy of many rural ranching and farming communities. Dairy operations are water intensive and use groundwater that otherwise would be used for irrigation purposes. Most dairies reuse their process/green water three times and utilize lined lagoons for temporary storage of green water. Leakage of water from lagoons can pose a risk to groundwater quality. Groundwater resource protection infrastructures at dairies are regulated by the New Mexico Environment Department which currently relies on monitoring wells installed in the saturated zone for detecting leakage of wastemore » water lagoon liners. Here we present a proposal to monitor the unsaturated zone beneath the lagoons with soil water solution samplers to provide early detection of leaking liners. Early detection of leaking liners along with rapid repair can minimize contamination of aquifers and reduce dairy liability for aquifer remediation. Additionally, acceptance of vadose zone monitoring as a NMED requirement over saturated zone monitoring would very likely significantly reduce dairy startup and expansion costs. Acknowledgment Funding for this project was provided by the Sandia National Laboratories Small Business Assistance Program« less

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.

Late Holocene sedimentation in a high Arctic coastal setting: Simpson Lagoon and Colville Delta, Alaska

NASA Astrophysics Data System (ADS)

Hanna, Andrea J. M.; Allison, Mead A.; Bianchi, Thomas S.; Marcantonio, Franco; Goff, John A.

2014-02-01

Arctic coastal environments near major river outfalls, like Simpson Lagoon, Alaska and the adjacent Colville River Delta, potentially contain high-resolution sediment records useful in elucidating late Holocene Arctic sediment transport pathways and coupled terrestrial-ocean evidence of paleoclimate variability. This study utilizes a multi-tracer geochronology approach (137Cs, 239,240Pu, and 14C) tailored for high-latitude environments to determine the age models for cores collected from Simpson Lagoon, and to date seismic boundaries in shallow acoustic reflection data (CHIRP) to examine late Holocene infill patterns. Modern (~100 y) sediment accumulation rates range from <0.02 to 0.46±0.04 cm y-1, with a primary depocenter in western Simpson Lagoon adjacent to the Colville Delta and a secondary depocenter in eastern Simpson Lagoon. CHIRP reflectors, age-constrained by 14C analysis, reveal rapid late Holocene (0-3500 y BP) transgression consistent with high modern shoreline retreat rates. The western depocenter contains >5 m of late Holocene interbedded sediments, likely derived primarily from the Colville River, with onset of accumulation occurring prior to ~3500 y BP. A paleo-high in central Simpson Lagoon, separating the two depocenters, was subaerially exposed prior to ~600 y BP. The millimeters-per-year sedimentation rates across the lagoon, coupled with the undisturbed, interbedded sediment record, indicate that these settings hold great potential to develop new Arctic paleoenvironmental records.

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

Assessment of temporal and spatial water quality in international Gomishan Lagoon, Iran, using multivariate analysis.

PubMed

Basatnia, Nabee; Hossein, Seyed Abbas; Rodrigo-Comino, Jesús; Khaledian, Yones; Brevik, Eric C; Aitkenhead-Peterson, Jacqueline; Natesan, Usha

2018-04-29

Coastal lagoon ecosystems are vulnerable to eutrophication, which leads to the accumulation of nutrients from the surrounding watershed over the long term. However, there is a lack of information about methods that could accurate quantify this problem in rapidly developed countries. Therefore, various statistical methods such as cluster analysis (CA), principal component analysis (PCA), partial least square (PLS), principal component regression (PCR), and ordinary least squares regression (OLS) were used in this study to estimate total organic matter content in sediments (TOM) using other parameters such as temperature, dissolved oxygen (DO), pH, electrical conductivity (EC), nitrite (NO 2 ), nitrate (NO 3 ), biological oxygen demand (BOD), phosphate (PO 4 ), total phosphorus (TP), salinity, and water depth along a 3-km transect in the Gomishan Lagoon (Iran). Results indicated that nutrient concentration and the dissolved oxygen gradient were the most significant parameters in the lagoon water quality heterogeneity. Additionally, anoxia at the bottom of the lagoon in sediments and re-suspension of the sediments were the main factors affecting internal nutrient loading. To validate the models, R 2 , RMSECV, and RPDCV were used. The PLS model was stronger than the other models. Also, classification analysis of the Gomishan Lagoon identified two hydrological zones: (i) a North Zone characterized by higher water exchange, higher dissolved oxygen and lower salinity and nutrients, and (ii) a Central and South Zone with high residence time, higher nutrient concentrations, lower dissolved oxygen, and higher salinity. A recommendation for the management of coastal lagoons, specifically the Gomishan Lagoon, to decrease or eliminate nutrient loadings is discussed and should be transferred to policy makers, the scientific community, and local inhabitants.

Assessing hydrological effects of human interventions on coastal systems: numerical applications to the Venice Lagoon

NASA Astrophysics Data System (ADS)

Ferrarin, C.; Ghezzo, M.; Umgiesser, G.; Tagliapietra, D.; Camatti, E.; Zaggia, L.; Sarretta, A.

2012-12-01

The hydrological consequences of historical, contemporary and future human activities on a coastal system were investigated by means of numerical models. The changes in the morphology of the Lagoon of Venice during the last century result from the sedimentological response to the combined effects of human interventions on the environment and global changes. This study focuses on changes from 1927 to 2012 and includes the changes planned for the protection of the city of Venice from storm surges and exceptional tides under future sea level rise scenarios. The application of a hydrodynamic model to simulate the circulation of water masses and the transport of a passive tracer enabled the analysis of the morphodynamic effects on the lagoon circulation and the interaction with the sea. The absolute values of the exchange between the lagoon and sea increased from 1927 to 2002 (from 3900 to 4600 m3 s-1), while the daily fraction of lagoon water volume exchanged decreased. At the same time, the water renewal time shortened from 11.9 to 10.8 days. Morphological changes during the last decade induced an increase of the basin-wide water renewal time (from 10.8 to 11.3 days). In the future, Venice Lagoon will evolve to a more restricted environment due to sea level rise and periodical closure of the lagoon from the sea during flooding events. Simulated scenarios of sea level rise showed that under fall-winter conditions the water renewal time will increased considerably especially in the central part of the lagoon. Furthermore, some considerations on the impact of the hydromorphological changes on the ecological dynamics are proposed.

Effects of biochar amendment on geotechnical properties of landfill cover soil.

PubMed

Reddy, Krishna R; Yaghoubi, Poupak; Yukselen-Aksoy, Yeliz

2015-06-01

Biochar is a carbon-rich product obtained when plant-based biomass is heated in a closed container with little or no available oxygen. Biochar-amended soil has the potential to serve as a landfill cover material that can oxidise methane emissions for two reasons: biochar amendment can increase the methane retention time and also enhance the biological activity that can promote the methanotrophic oxidation of methane. Hydraulic conductivity, compressibility and shear strength are the most important geotechnical properties that are required for the design of effective and stable landfill cover systems, but no studies have been reported on these properties for biochar-amended landfill cover soils. This article presents physicochemical and geotechnical properties of a biochar, a landfill cover soil and biochar-amended soils. Specifically, the effects of amending 5%, 10% and 20% biochar (of different particle sizes as produced, size-20 and size-40) to soil on its physicochemical properties, such as moisture content, organic content, specific gravity and pH, as well as geotechnical properties, such as hydraulic conductivity, compressibility and shear strength, were determined from laboratory testing. Soil or biochar samples were prepared by mixing them with 20% deionised water based on dry weight. Samples of soil amended with 5%, 10% and 20% biochar (w/w) as-is or of different select sizes, were also prepared at 20% initial moisture content. The results show that the hydraulic conductivity of the soil increases, compressibility of the soil decreases and shear strength of the soil increases with an increase in the biochar amendment, and with a decrease in biochar particle size. Overall, the study revealed that biochar-amended soils can possess excellent geotechnical properties to serve as stable landfill cover materials. © The Author(s) 2015.

Temporal coherence among tropical coastal lagoons: a search for patterns and mechanisms.

PubMed

Caliman, A; Carneiro, L S; Santangelo, J M; Guariento, R D; Pires, A P F; Suhett, A L; Quesado, L B; Scofield, V; Fonte, E S; Lopes, P M; Sanches, L F; Azevedo, F D; Marinho, C C; Bozelli, R L; Esteves, F A; Farjalla, V F

2010-10-01

Temporal coherence (i.e., the degree of synchronicity of a given variable among ecological units within a predefined space) has been shown for several limnological features among temperate lakes, allowing predictions about the structure and function of ecosystems. However, there is little evidence of temporal coherence among tropical aquatic systems, where the climatic variability among seasons is less pronounced. Here, we used data from long-term monitoring of physical, chemical and biological variables to test the degree of temporal coherence among 18 tropical coastal lagoons. The water temperature and chlorophyll-a concentration had the highest and lowest temporal coherence among the lagoons, respectively, whereas the salinity and water colour had intermediate temporal coherence. The regional climactic factors were the main factors responsible for the coherence patterns in the water temperature and water colour, whereas the landscape position and morphometric characteristics explained much of the variation of the salinity and water colour among the lagoons. These results indicate that both local (lagoon morphometry) and regional (precipitation, air temperature) factors regulate the physical and chemical conditions of coastal lagoons by adjusting the terrestrial and marine subsidies at a landscape-scale. On the other hand, the chlorophyll-a concentration appears to be primarily regulated by specific local conditions resulting in a weak temporal coherence among the ecosystems. We concluded that temporal coherence in tropical ecosystems is possible, at least for some environmental features, and should be evaluated for other tropical ecosystems. Our results also reinforce that aquatic ecosystems should be studied more broadly to accomplish a full understanding of their structure and function.

Lagoons and Reefs of New Caledonia

NASA Image and Video Library

2011-04-20

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

Stage-specific distribution models can predict eel (Anguilla anguilla) occurrence during settlement in coastal lagoons

NASA Astrophysics Data System (ADS)

Leone, C.; Zucchetta, M.; Capoccioni, F.; Gravina, M. F.; Franzoi, P.; Ciccotti, E.

2016-03-01

Eel (Anguilla anguilla) is a catadromous fish species typical of Mediterranean coastal lagoons, that currently suffers from several anthropogenic and natural impacts. These are thought to be the cause of a stock-wide decline that this panmictic species is facing, in inland and coastal waters of Europe and North Africa. The decline affects both adult phases and recruitment, i.e. glass eel arrival to coastal waters and their ascent to inland waters. Quantitative features of eel recruitment reflect a transoceanic global scale, but also depend on local environmental conditions, the latter also affecting settlement dynamics in transitional waters. There is only little information on the dynamics of these two processes in coastal lagoons, notwithstanding the paramount importance of both in sustaining local stocks abundance and their demographic structure for this typical but also economically important inhabitant of Mediterranean lagoons, habitats that constitute an important share of the eel distribution area. The present study aims, therefore, to clarify space and time dynamics of local scale recruitment and of settlement in a coastal lagoon in the Mediterranean area, also by setting up a specific methodological approach. For this purpose, data from field surveys in combination with Species Distribution Models (SDMs) have been used in order to relate distribution of eel juvenile stages to the environmental conditions within the lagoon. Specifically, models were calibrated to quantify the relationship between presence of juvenile eel and the main environmental drivers, with the aim of identifying potential habitats for eel settlement within the lagoon. Results gained by modelling suggest certain spatial and temporal colonization patterns for the juvenile eel in the Fogliano lagoon, a typical Mediterranean coastal lake. The modelling approach has therefore proved to be a useful tool for predicting habitats for eel recruitment at the local scale and settlement, because

Evaluation of some heavy metal loading in the Kpeshi lagoon, Ghana

NASA Astrophysics Data System (ADS)

Fianko, Joseph R.; Laar, Cynthia; Osei, Juilet; Anim, Alfred K.; Gibrilla, Abass; Adomako, Dickson

2013-03-01

A study was carried out on the Kpeshi lagoon to evaluate the relative contributions of some heavy metals (Na, k, Ca, K, Fe, Mn, Ni, Cr, Cd, Al, Pb) on the current state of the Kpeshi lagoon. The lagoon water was sampled along with some fish samples. Water pH, electrical conductivity and total dissolved salts were measured in situ whilst Na and K were measured using flame emission spectrometry. Heavy metals (iron, manganese, nickel, aluminium, chromium, lead and cadmium) in both water and fish samples were analyzed using atomic absorption spectrometry. Measured pH values ranged between 6.60 and 7.87, a mean conductivity and total dissolved salts of 87.31 ± 19.14 μS/cm and 38.4 ± 8.43 mg/L, respectively. Nutrient and organic matter were among the frequent source of pollution in the lagoon with mean sulphate, phosphate and nitrate concentrations of 190 ± 108.84, 1.62 ± 0.49 and 0.89 ± 0.26 mg/L, respectively. Iron and aluminium in the lagoon water measured the highest concentration of 13.2 ± 3.47 and 13.6 ± 4.29 mg/L, respectively. Fish samples however revealed very high concentrations of calcium and potassium measuring 15,709 ± 75.35 and 5,949.49 ± 87.30 mg/kg, respectively. Sodium and aluminium also revealed relatively high concentrations: 3,775.70 ± 24.80 and 708.47 ± 4.95 mg/kg, respectively. Notably, sites closer to settlement community (Teshie Township, e.g. S1, S2, S3 and S4) and the hospitality industries (i.e. dotted hotels, e.g. S7) appeared to be relatively more contaminated.

Using Methane Absorption to Probe Jupiter's Atmosphere

NASA Technical Reports Server (NTRS)

1997-01-01

Mosaics of a belt-zone boundary near Jupiter's equator in near-infrared light moderately absorbed by atmospheric methane (top panel), and strongly absorbed by atmospheric methane (bottom panel). The four images that make up each of these mosaics were taken within a few minutes of each other. Methane in Jupiter's atmosphere absorbs light at specific wavelengths called absorption bands. By detecting light close and far from these absorption bands, Galileo can probe to different depths in Jupiter's atmosphere. Sunlight near 732 nanometers (top panel) is moderately absorbed by methane. Some of the light reflected from clouds deep in Jupiter's troposphere is absorbed, enhancing the higher features. Sunlight at 886 nanometers (bottom panel) is strongly absorbed by methane. Most of the light reflected from the deeper clouds is absorbed, making these clouds invisible. Features in the diffuse cloud layer higher in Jupiter's atmosphere are greatly enhanced.

North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Anaerobic methane oxidation in low-organic content methane seep sediments

USGS Publications Warehouse

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

2013-01-01

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

Tidal dynamics of the Terminos Lagoon, Mexico: observations and 3D numerical modelling

NASA Astrophysics Data System (ADS)

Contreras Ruiz Esparza, Adolfo; Douillet, Pascal; Zavala-Hidalgo, Jorge

2014-09-01

The tidal circulation patterns in the Terminos Lagoon were studied based on the analysis of 1 year of measurements and numerical simulations using a baroclinic 3D hydrodynamic model, the MARS3D. A gauging network was installed consisting of six self-recording pressure-temperature sensors, a tide gauge station and two current profilers, with pressure and temperature sensors moored in the main lagoon inlets. Model simulations were validated against current and sea level observations and were used to analyse the circulation patterns caused by the tidal forcing. The numerical model was forced with eight harmonic components, four diurnal ( K 1, O 1, P 1, Q 1) and four semi-diurnal ( M 2, S 2, N 2, K 2), extracted from the TPX0.7 database. The tidal patterns in the study area vary from mixed, mainly diurnal in the two main inlets of the lagoon, to diurnal in its interior. The tidal residual circulation inside the lagoon is dominated by a cyclonic gyre. The results indicate a net flux from the southwest Ciudad del Carmen inlet (CdC) towards the northeast Puerto Real inlet (PtR) along the southern side of the lagoon and the opposite in the northern side. The results indicate two areas of strong currents in the vicinity of the inlets and weak currents inside the lagoon. The area of strong currents in the vicinity of the CdC inlet is larger than that observed in the PtR inlet. Nevertheless, the current analysis indicates that the highest current speeds, which can reach a magnitude of 1.9 m s-1, occurred in PtR. A further analysis of the tide distortion in the inlets revealed that both passages are ebb dominated.

Biotic variation in coastal water bodies in Sussex, England: Implications for saline lagoons

NASA Astrophysics Data System (ADS)

Joyce, Chris B.; Vina-Herbon, Cristina; Metcalfe, Daniel J.

2005-12-01

Coastal water bodies are a heterogeneous resource typified by high spatial and temporal variability and threatened by anthropogenic impacts. This includes saline lagoons, which support a specialist biota and are a priority habitat for nature conservation. This paper describes the biotic variation in coastal water bodies in Sussex, England, in order to characterise the distinctiveness of the saline lagoon community and elucidate environmental factors that determine its distribution. Twenty-eight coastal water bodies were surveyed for their aquatic flora and invertebrate fauna and a suite of exploratory environmental variables compiled. Ordination and cluster analyses were used to examine patterns in community composition and relate these to environmental parameters. Biotic variation in the coastal water body resource was high. Salinity was the main environmental parameter explaining the regional distribution of taxa; freshwater and saline assemblages were evident and related to sea water ingress. Freshwater sites were indicated by the plant Myriophyllum spicatum and gastropod mollusc Lymnaea peregra, while more saline communities supported marine and brackish water taxa, notably a range of chlorophytic algae and the bivalve mollusc Cerastoderma glaucum. Site community differences were also related to bank slope and parameters describing habitat heterogeneity. A saline lagoon community was discerned within the matrix of biotic variation consisting of specialist lagoonal species with associated typically euryhaline taxa. For fauna, the latter were the molluscs Abra tenuis and Hydrobia ulvae, and the crustaceans Corophium volutator and Palaemonetes varians, and for flora they were the algae Ulva lactuca, Chaetomorpha mediterranea, Cladophora spp. and Enteromorpha intestinalis. One non-native polychaete species, Ficopomatus enigmaticus, also strongly influenced community structure within the lagoonal resource. The community was not well defined as specialist and

Organic matter composition in the sediment of three Brazilian coastal lagoons: district of Macaé, Rio de Janeiro (Brazil).

PubMed

Zink, Klaus-Gerhard; Furtado, André L S; Casper, Peter; Schwark, Lorenz

2004-03-01

Freshwater lagoons comprise important coastal ecosystems and natural buffers between urbanized land areas and open ocean in the Rio de Janeiro State, Brazil. Studies of sediment and water chemistry, zooplankton and bacterial communities to assess the extent of anthropogenic disturbance are available. Here we contribute with an organic-geochemical approach supplemented by some microbiological aspects to complete the characterization of these lagoonal ecosystems. Bulk organic matter and extractable lipids (aliphatic hydrocarbons, alcohols and fatty acids, sterols) were investigated from two locations per lagoon: at the seaward site and landward ends - and at two depth intervals (0-3 and 3-6 cm) per site. Urbanized Imboacica Lagoon received increased anthropogenic input over the most recent years represented by the topmost 3 cm of sediment, whereas deeper sediment layers are less affected by human influence. Eutrophication or nutrient availability favored enhanced algal/cyanobacterial growth. In remote Cabiúnas and Comprida Lagoons pristine conditions are preserved. Organic matter from vascular plants dominates (chain length of free lipids up to C36), which is exceptionally well preserved by acidic lagoonal waters. Differentiation between landward and seaward sites in these two lagoons is less well established due to much smaller surface/volume to catchment ratios. No anthropogenic influences are yet detectable in sediments of Cabiúnas and Comprida Lagoons.

Metal pollution loading, Manzalah lagoon, Nile delta, Egypt: Implications for aquaculture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siegel, F.R.; Slaboda, M.L.; Stanley, D.J.

1994-03-01

High cultural enrichment factors are found for Hg (13 x), Pb (22.1 x), and other potentially toxic metals (e.g., Sn, Zn, Cu, Ag) in the upper 20 cm of sediment cores from the southeastern Ginka subbasin of Manzalah lagoon, Nile delta, Egypt. Cores from other areas of the lagoon show little metal loading. Metal loading followed the closure of the Aswan High Dam, the availability of abundant cheap electricity, and the development of major power-based industries. Industrial wastes containing potentially toxic metals are dumped into the Nile delta drain system. The load carried by Bahr El-Baqar drain discharges into themore » Ginka subbasin, which acts as a sink and results in metal loading of the sediment deposited there. Further development of aquaculture in this subbasin, of food-stuff agriculture on recently reclaimed lagoon bottom, or where irrigation waters come from Bahr El-Baqar drain or its discharge should be halted or strictly limited until potentially toxic metals in the drain waters and sediment are removed and polluted input drastically reduced. This environmental assessment of heavy metals in aquaculture or agriculture development should extend to other waterbodies in the northern Nile delta, particularly Idku lagoon and Lake Mariut, where industrial metal-bearing wastes discharge into the waterbodies. 21 refs., 7 figs., 3 tabs.« less

Adsorption and transport of methane in biochars derived from waste wood.

PubMed

Sadasivam, Bala Yamini; Reddy, Krishna R

2015-09-01

Mitigation of landfill gas (LFG) is among the critical aspects considered in the design of a landfill cover in order to prevent atmospheric pollution and control global warming. In general, landfill cover soils can partially remove methane (CH4) through microbial oxidation carried out by methanotrophic bacteria present within them. The oxidizing capacity of these landfill cover soils may be improved by adding organic materials, such as biochar, which increase adsorption and promote subsequent or simultaneous oxidation of CH4. In this study, seven wood-derived biochars and granular activated carbon (GAC) were characterized for their CH4 adsorption capacity by conducting batch and small-scale column studies. The effects of influential factors, such as exposed CH4 concentration, moisture content and temperature on CH4 adsorption onto biochars, were determined. The CH4 transport was modeled using a 1-D advection-dispersion equation that accounted for sorption. The effects of LFG inflow rates and moisture content on the combined adsorption and transport properties of biochars were determined. The maximum CH4 adsorption capacity of GAC (3.21mol/kg) was significantly higher than that of the biochars (0.05-0.9mol/kg). The CH4 gas dispersion coefficients for all of the biochars ranged from 1×10(-3) to 3×10(-3)m(2)s(-1). The presence of moisture significantly suppressed the extent of methane adsorption onto the biochars and caused the methane to break through within shorter periods of time. Overall, certain biochar types have a high potential to enhance CH4 adsorption and transport properties when used as a cover material in landfills. However, field-scale studies need to be conducted in order to evaluate the performance of biochar-based cover system under a more dynamic field condition that captures the effect of seasonal and temporal changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distribution and sources of carbon, nitrogen, phosphorus and biogenic silica in the sediments of Chilika lagoon

NASA Astrophysics Data System (ADS)

Nazneen, Sadaf; Raju, N. Janardhana

2017-02-01

The present study investigated the spatial and vertical distribution of organic carbon (OC), total nitrogen (TN), total phosphorus (TP) and biogenic silica (BSi) in the sedimentary environments of Asia's largest brackish water lagoon. Surface and core sediments were collected from various locations of the Chilika lagoon and were analysed for grain-size distribution and major elements in order to understand their distribution and sources. Sand is the dominant fraction followed by silt + clay. Primary production within the lagoon, terrestrial input from river discharge and anthropogenic activities in the vicinity of the lagoon control the distribution of OC, TN, TP and BSi in the surface as well as in the core sediments. Low C/N ratios in the surface sediments (3.49-3.41) and cores (4-11.86) suggest that phytoplankton and macroalgae may be major contributors of organic matter (OM) in the lagoon. BSi is mainly associated with the mud fraction. Core C5 from Balugaon region shows the highest concentration of OC ranging from 0.58-2.34%, especially in the upper 30 cm, due to direct discharge of large amounts of untreated sewage into the lagoon. The study highlights that Chilika is a dynamic ecosystem with a large contribution of OM by autochthonous sources with some input from anthropogenic sources as well.

Lacaziosis in bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida, USA.

PubMed

Durden, Wendy Noke; St Leger, Judy; Stolen, Megan; Mazza, Teresa; Londono, Catalina

2009-07-01

The objective of this study was to document the presence of the fungal granulomatous skin disease lacaziosis in stranded Indian River Lagoon (IRL) bottlenose dolphins (Tursiops truncatus). From 1 January 2007 through 31 December 2007, stranded dolphins from the northern part of the IRL were thoroughly examined, and appropriate tissue samples were collected. The intralesional fungal agent (Lacazia loboi) was identified histologically in three bottlenose dolphins. Histologically, lacaziosis has been previously documented in IRL dolphins inhabiting the southern portion of the lagoon. Our findings suggest that the disease occurs throughout the lagoon. Enhanced monitoring of the prevalence of lacaziosis in dolphins throughout the IRL is needed to assess changes in population health.

The Defense Committees of Sleepy Lagoon: A Convergent Struggle against Fascism, 1942-1944

ERIC Educational Resources Information Center

Barajas, Frank P.

2006-01-01

The Sleepy Lagoon Defense Committee originated as an ad hoc committee and evolved to a broad-based movement for legal justice on behalf of seventeen youth convicted of murder and assault charges in connection with the Sleepy Lagoon case in Los Angeles in January 1943. This essay chronicles the multidimensional organizing to shift public opinion in…

[Mangrove dynamics in the Cispata lagoon system (Colombian Caribbean) during last 900 years].

PubMed

Castaño, Ana; Urrego, Ligia; Bernal, Gladys

2010-12-01

The lagoon complex of Cispatá (old Sinú river delta) located at the Northwestern coast of the Colombian Caribbean, encloses one of the biggest mangrove areas in this region. This area has changed during the last 330 years because of several environmental and climatic causes, mainly changes in the position of the delta (Sinú River), which is the main freshwater source in this area, and sea level rise. We hypothesized that the climatic and geomorphologic dynamics has caused changes in the extension and composition of mangrove vegetation, especially during last 150 years. The dynamics of mangroves during the last 900 years was reconstructed based on the changes in the stratigraphy, pollen record, calcite concentrations (CaCO3) and C/N ratio, along two sediment cores from La Flotante and Navio lagoons, located in Cispatá complex. The age model was built based on lineal interpolation of 210Pb ages and changes in granulometry. Establishment and expansion of mangrove forests during the last 900 years were related to fluviomarine dynamics in the area and the lagoon formation. During the period encompassed between 1064 and 1762 A.D., the Mestizos spit was formed when marine conditions predominated in the surroundings of La Flotante Lagoon. At the site of Navío, a river dominated lagoon, terrigenous conditions dominated since 1830. Although the colonization of herbaceous pioneer vegetation started between 1142 and 1331 A.D., mangrove colonization only took place since 1717 A.D. Mangrove colonization was a result of the delta progradation. In 1849 A.D. the Sinú river delta migrated to the Cispatá bay. The eustatic sea level rise, the increase in river discharges and sedimentation rates produced the establishment of mangrove forests dominated by Rhizophora since 1849. Since 1900 a marine intrusion was recorded in both lagoons. In 1938, the migration of the delta toward its actual location in Tinajones gave place to the formation of the present lagoon system and to the

A new sampler for stratified lagoon chemical and microbiological assessments.

PubMed

McLaughlin, M R; Brooks, J P; Adeli, A

2014-07-01

A sampler was needed for a spatial and temporal study of microbial and chemical stratification in a large swine manure lagoon that was known to contain zoonotic bacteria. Conventional samplers were limited to collections of surface water samples near the bank or required a manned boat. A new sampler was developed to allow simultaneous collection of multiple samples at different depths, up to 2.3 m, without a manned boat. The sampler was tethered for stability, used remote control (RC) for sample collection, and accommodated rapid replacement of sterile tubing modules and sample containers. The sampler comprised a PVC pontoon with acrylic deck and watertight enclosures, for a 12 VDC gearmotor, to operate the collection module, and vacuum system, to draw samples into reusable autoclavable tubing and 250-mL bottles. Although designed primarily for water samples, the sampler was easily modified to collect sludge. The sampler held a stable position during deployment, created minimal disturbance in the water column, and was readily cleaned and sanitized for transport. The sampler was field tested initially in a shallow fresh water lake and subsequently in a swine manure treatment lagoon. Analyses of water samples from the lagoon tests showed that chemical and bacterial levels, pH, and EC did not differ between 0.04, 0.47, and 1.0 m depths, but some chemical and bacterial levels differed between winter and spring collections. These results demonstrated the utility of the sampler and suggested that future manure lagoon studies employ fewer or different depths and more sampling dates.

Calibration of Linked Hydrodynamic and Water Quality Model for Santa Margarita Lagoon

DTIC Science & Technology

2016-07-01

was used to drive the transport and water quality kinetics for the simulation of 2007–2009. The sand berm, which controlled the opening/closure of...TECHNICAL REPORT 3015 July 2016 Calibration of Linked Hydrodynamic and Water Quality Model for Santa Margarita Lagoon Final Report Pei...Linked Hydrodynamic and Water Quality Model for Santa Margarita Lagoon Final Report Pei-Fang Wang Chuck Katz Ripan Barua SSC Pacific James

Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia) in Two Contrasting Lagoons in French Polynesia

PubMed Central

Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Wabnitz, Colette C. C.; Menoud, Mathilde; Le Moullac, Gilles; Levy, Peva; Gilbert, Antoine; Remoissenet, Georges

2017-01-01

Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems. PMID:28118406

Mud deposit formation on the open coast of the larger Patos Lagoon-Cassino Beach system

NASA Astrophysics Data System (ADS)

Vinzon, S. B.; Winterwerp, J. C.; Nogueira, R.; de Boer, G. J.

2009-03-01

This paper proposes an explanation of the mud deposits on the inner Shelf of Cassino Beach, South Brazil, by using computational modeling. These mud deposits are mainly formed by sediments delivered from Patos Lagoon, a coastal lagoon connected to the Shelf, next to Cassino Beach. The deposits are characterized by (soft) mud layers of about 1 m thick and are found between the -5 and -20 isobaths. Two hydrodynamic models of the larger Patos Lagoon-Cassino Beach system were calibrated against water elevation measured for a 5 months period, and against currents and salinity measured for a week period. The circulation patterns and water exchange through the mouth were analyzed as a function of local and remote wind effects, and river discharges. The remote wind effect mainly governs the quantity of water exchange with the Lagoon through its effect on mean sea level as a result of Ekman dynamics, while river discharges are important for the salinity of the exchanged water masses. Local winds augment the export-import rates by set-up and set-down within the Lagoon, but their effects are much smaller than those of the remote wind. Currents patterns on the inner Shelf during water outflow revealed a recirculation zone south of the Lagoon, induced by the local geometry and bathymetry of the system. This recirculation zone coincides with observed locations of mud deposition. Water, hence suspended sediment export occurs when remote and local winds are from the N-E, which explains why fine sediment deposits are mainly found south of the Lagoon's breakwater. A sensitivity analysis with the numerical model quantified the contribution of the various mechanisms driving the transport and fate of the fine suspended sediments, i.e. the effects of remote and local wind, of the astronomical tide, of river discharge and fresh-salt water-induced density currents, and of earth rotation. It is concluded that gravitational circulation and earth rotation affects the further dispersion of

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

PubMed Central

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

2015-01-01

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

Mapping of West Siberian taiga wetland complexes using Landsat imagery: Implications for methane emissions

NASA Astrophysics Data System (ADS)

Terentieva, Irina; Sabrekov, Alexander; Glagolev, Mikhail; Maksyutov, Shamil

2017-04-01

Boreal wetlands are important for understanding climate change risks because these environments sink carbon dioxide and emit methane. The West Siberia Lowland (WSL) is the biggest peatland area in Eurasia and is situated in the high latitudes experiencing enhanced rate of climate change. However, fine-scale heterogeneity of wetland landscapes poses a serious challenge when generating regional-scale estimates of greenhouse gas fluxes from point observations. A number of peatland maps of the West Siberia was developed in 1970s, but their accuracy is limited. In order to reduce uncertainties at the regional scale, we mapped wetlands and water bodies in the WSL on a scene-by-scene basis using a supervised classification of Landsat imagery. Training data consisted of high-resolution images and extensive field data collected at 41 test areas. The classification scheme aimed at supporting methane inventory applications and included 7 wetland ecosystem types comprising 9 wetland complexes distinguishable at the Landsat resolution. To merge typologies, mean relative areas of wetland ecosystems within each wetland complex type were estimated using high-resolution images. Accuracy assessment based on 1082 validation polygons of 10×10 pixels indicated an overall map accuracy of 79%. The total area of the WSL wetlands and water bodies was estimated to be 70.78 Mha or 5-17% of the global wetland area. Various oligotrophic environments are dominant among wetland ecosystems, while different fens cover only 14% of the area. Taiga zone contains 75% of WSL's wetlands; their distribution was described in detail by Terentieva et al. (2016). Concerning methane emission, taiga contributes 85% to regional methane flux and tundra only 8%, however ebullition in tundra lakes was not directly measured. Elevated environments as forested bogs and ridges emit at the lowest rates of methane emission. They account for only 2% of the regional total emissions occupying almost 40% of the wetland

Root-Associated Methane Oxidation and Methanogenesis: Key Determinants of Wetland Methane Emissions

NASA Technical Reports Server (NTRS)

King, G. M.

1997-01-01

During the award period, we have assessed the extent and controls of methane oxidation in north temperate wetlands. It is evident that wetlands have been a major global source of atmospheric methane in the past, and are so at present. It is also evident that microbial methane oxidation consumes a variable fraction of total wetland methane production, perhaps 10%-90%. Methane oxidation is thus a potentially important control of wetland methane emission. Our efforts have been designed to determine the extent of the process, its controls, and possible relationships to changes that might be expected in wetlands as a consequence of anthropogenic or climate-related disturbances. Current work, has emphasized controls of methane oxidation associated with rooted aquatic plants. As for the sediment-water interface, we have observed that oxygen availability is a primary limiting factor. Our conclusion is based on several different lines of evidence obtained from in vitro and in situ analyses. First, we have measured the kinetics of methane oxidation by intact plant roots harboring methane-oxidizing bacteria, as well as the kinetics of the methanotrophs themselves. Values for the half-saturation constant (apparent K(sub m)) are approximately 5 microns. These values are roughly equivalent to, or much less than porewater methane concentrations, indicating that uptake is likely saturated with respect to methane, and that some other parameter must limit activity. Methane concentrations in the lacunar spaces at the base of plant stems are also comparable to the half-saturation constants (when expressed as equivalent dissolved concentrations), providing further support for limitation of uptake by parameters other than methane.

Hydrological behavior of coastal lagoons associated to wetlands, an example from southernmost bahía Samborombón (Argentina).

NASA Astrophysics Data System (ADS)

Tejada Tejada, Macarena; Carol, Eleanora; Galliari, Julieta; Richiano, Sebastian

2017-04-01

Coastal wetlands are located at a critical interface between the terrestrial and marine environments and are ideally positioned to reduce impacts from land-based sources. At the southern region of Bahía Samborombón (Argentina) the wetlands includes several small coastal lagoons developed inside of a sandy spike. The main object of this work is to analyze the hydrological behavior of the lagoons evaluating their role in the maintenances of the wetland. In order to do this, satellite image analysis was performed to identify the marshy areas, drainage features, morphology and connections of the lagoons, both with the tidal flows from the Río de la Plata estuary and from the Argentine Sea. Field surveys were carried out in one of the lagoons to define their geological and geomorphological characteristics. After that, a monitoring network was designed for sampling the superficial and the underground water, additionally electrical conductivity and pH of the water were determined in situ. In all the water samples extracted the content of majority ions was determined by standard methods. Complementary, sedimentological and malacological aspects were observed at several stations in the lagoon. The obtained results allow us to recognize that the tidal flow that enters from the sea, at least in the studied lagoon, is the main hydrological sustenance of the wetland. This flow enters mainly using one tidal channel which connects (in a semi-permanent way) the sea with the lagoon during extraordinary tide and storm events. During low tide the lagoon loses connection and the drainage towards the sea is scarce. The tidal water that accumulates in the lagoon is subsequently evaporated causing an increase in the salinity of the surface water to values higher than the sea. Groundwater that accumulates through the infiltration of rainfall in the sandy sediments of the spike also discharges to the lagoon and supports the wetland surrounding the coastal lagoon. This flow, even when it

Microcystins Presence in Mussels (M. galloprovincialis) and Water of Two Productive Mediterranean's Lagoons (Sardinia, Italy)

PubMed Central

Baralla, Elena; Varoni, Maria Vittoria; Sedda, Tiziana; Floris, Antonello; Demontis, Maria Piera

2017-01-01

Microcystins (MCs) are hepatotoxins harmful for animal and human health. The most toxic type between them is MC-LR whose presence has been investigated in different reservoirs all around the world. In this work microcystins were monitored in spring and summer in water and mussels (Mytilus galloprovincialis) of two Sardinia lagoons: Cabras and Calich lagoons. A Solid Phase Extraction method was developed to clean and concentrate samples before the Enzyme Linked Immunosorbent Assay (ELISA) and the following Mass Spectrometry detection. MCs presence was detected using the screening ELISA test in both lagoons. MCs peak was revealed in July for water and mussels belonging to Cabras lagoon (0.75 ± 0.07 ng/L in water and 0.12 ± 0.04 ng/g ww in mussels). In water of Calich lagoon there was a constant trend in the concentration of MCs during the considered months, while there was a MCs peak in July (0.6 ± 0.5 ng/g ww) in mussels. The following LC-MS/MS analysis did not reveal MC-LR presence in all analyzed samples. These results can be useful to enrich knowledge on public health and consumer's safeguard. PMID:29359150

Methane Fingerprinting: Isotopic Methane and Ethane-to-Methane Ratio Analysis Using a Cavity Ring-Down Spectrometer

NASA Astrophysics Data System (ADS)

Saad, Nabil; Fleck, Derek; Hoffnagle, John

2016-04-01

Emissions of Natural gas, and methane (CH4) specifically, have come under increased scrutiny by virtue of methane's 28-36x greenhouse warming potential compared to carbon dioxide (CO2) while accounting for 10% of the total greenhouse gas emissions in the US. Large uncontrolled leaks, such as the recent Aliso Canyon leak, originating from uncapped wells, coal mines and storage facilities have increased the total global contribution of methane missions even further. Determining the specific fingerprint of methane sources, by quantifying δ13C values and C2:C1 ratios, provides the means to understand methane producing processes and allows for sources of methane to be mapped and classified through these processes; i.e. biogenic vs. thermogenic, wet vs dry. In this study we present a fully developed Cavity Ring-Down Spectrometer (CRDS) that precisely measures 12CH4 concentration and its 13CH4 isotope concentration, yielding δ13C measurements, C2H6 concentration, along with CO2 and H2O. This provides real-time continuous measurements without an upfront separation requirement or multiple analyses to derive the origin of the gas samples. The highly sensitive analyzer allows for measurements of scarce molecules down to sub-ppb 1-σ precision in 5 minutes of measurement: with CH4 <0.1ppb, δ13C <1‰ C2H6 <1ppb and CO2 <1ppm. To complement this work, we provide the analysis of different methane sources providing a 2-dimensional mapping of methane sources as functions of δ13C and C2:C1 ratios, which can be thought of as a modified Bernard Plot. This dual ratio mapping can be used to discriminate between naturally occurring biogenic methane sources, naturally occurring enriched thermogenic sources, and natural gas distribution sources. This also shows future promise in aiding gas and oil exploration, in distinguishing oil vs coal gases, as well as a valuable tool in the development of methane sequestration.

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.

Engineering of Methane Metabolism in Pichia Pastoris Through Methane Monooxygenase Expression

NASA Technical Reports Server (NTRS)

Fleury, Samantha T.; Neff, Lily S.; Galazka, Jonathan M.

2017-01-01

Exploration of the solar system is constrained by the cost of moving mass off Earth. Producing materials in situ will reduce the mass that must be delivered from earth. CO2 is abundant on Mars and manned spacecraft. On the ISS, NASA reacts excess CO2 with H2 to generate CH4 and H2O using the Sabatier System. The resulting water is recovered into the ISS, but the methane is vented to space. Thus, there is a capability need for systems that convert methane into valuable materials. Methanotrophic bacteria consume methane but these are poor synthetic biology platforms. Thus, there is a knowledge gap in utilizing methane in a robust and flexible synthetic biology platform. The yeast Pichia pastoris is a refined microbial factory that is used widely by industry because it efficiently secretes products. Pichia could produce a variety of useful products in space. Pichia does not consume methane but robustly consumes methanol, which is one enzymatic step removed from methane. Our goal is to engineer Pichia to consume methane thereby creating a powerful methane-consuming microbial factory.

Behavior and influence of desiccation cracking in loess landfill covers

NASA Astrophysics Data System (ADS)

Wu, Tao; Lan, Ji-wu; Qiu, Qing-wen; He, Hai-jie; Li, He

2017-11-01

In the northwest region of China, loess was the main closure cover material of local landfills. Tests in a full-scale testing facility were conducted to investigate the behavior and influence of desiccation cracking in loess landfill covers. The desiccation cracks in the loess landfill cover intersected with T-shape, and the intersection angles were close to 90 degrees. The desiccation cracks formed as a result of drying, and would heal with the increase of moisture content of the loess. In addition, desiccation cracking in loess covers would promote the formation of preferential flow channels. As a consequence, the gas permeability of the loess cover was improved, and methane emissions increased obviously.

Water-Quality Monitoring and Biological Integrity Assessment in the Indian River Lagoon, Florida: Status, Trends, and Loadings (1988-1994).

PubMed

Sigua; Steward; Tweedale

2000-02-01

/ The Indian River Lagoon (IRL) system that extends from Ponce DeLeon Inlet to Jupiter Inlet is comprised of three interconnected estuarine lagoons: the Mosquito Lagoon (ML), the Banana River Lagoon (BRL), and the Indian River Lagoon (subdivided into North Indian River Lagoon, NIRL and the South Indian River Lagoon, SIRL). The declines in both the areal coverage and species diversity of seagrass communities within the IRL system are believed to be due in part to continued degradation of water quality. Large inflows of phosphorus (P) and nitrogen (N) -laden storm-water from urban areas and agricultural land have been correlated with higher chlorophyll a production in the central, south central, and the south segments of the lagoon. In a system as large and complex as the lagoon, N and P limitations are potentially subject to significant spatial and temporal variability. Total Kjeldahl nitrogen (TN) was higher in the north (1.25 mg/liter) and lower in the south (0.89 mg/liter). The reverse pattern was observed for total P (TP), i.e., lowest in the north (0.03 mg/liter) and highest at the south (0.14 mg/liter) ends of the IRL. This increased P concentration in the SIRL appears to have a significantly large effect on chlorophyll a production compared with the other segments, as indicated by stepwise regression statistics. This relationship can be expressed as follows: South IRL [chlorophyll a] = -8.52 + 162.41 [orthophosphate] + 7.86 [total nitrogen] + 0.38 [turbidity]; R(2) = 0.98**.

Tracing organic matter sources in a tropical lagoon of the Caribbean Sea

NASA Astrophysics Data System (ADS)

Alonso-Hernández, Carlos M.; Garcia-Moya, Alejandro; Tolosa, Imma; Diaz-Asencio, Misael; Corcho-Alvarado, Jose Antonio; Morera-Gomez, Yasser; Fanelli, Emanuela

2017-09-01

The natural protected lagoon of Guanaroca, located between Cienfuegos Bay and the Arimao River, Cuba, has been heavily impacted by human-induced environmental changes over the past century. Sources of organic matter in the Guanaroca lagoon and concentrations of radioisotopes (210Pb, 226Ra, 137Cs and 239,240Pu), as tracers of anthropogenic impacts, were investigated in a 78 cm sediment core. Variations in total organic carbon (TOC), total nitrogen (TN), stable isotopic composition (δ13C and δ15N) and ratio of total organic carbon to total nitrogen (C/N) were analysed. On such a basis, environmental changes in the lagoon were revealed. Down core variation patterns of the parameters representing sources of organic matter were predominantly related to the impacts of human activities. Up to the nineteenth century, the principal sources of organic matter to sediments (more than 80%) were a mixing of terrestrial vascular plants ( 48%) and freshwater phytoplankton ( 8%), with minimal contribution from the marine component ( 16%). In the period 1900-1980, due to the strong influence of human activities in the catchment area, the water exchange capacity of the lagoon declined substantially, as indicated by the relatively high proportion of organic matter originated from human activities (58%). Since 1980, as a result of management actions in the protected area, the lagoon has regained gradually its capability to exchange freshwater, showing sources of organic matter similar to the natural conditions recorded previous to 1900, although an indication of human impact (treated sewage contributed for 26% to the organic matter in sediments) was still observed and further management measures would be required.

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.

Low methane flux from a constructed boreal wetland

NASA Astrophysics Data System (ADS)

Clark, M. G.; Humphreys, E.; Carey, S. K.

2016-12-01

The Sandhill Fen Watershed project in northern Alberta, Canada, is a pilot study in reconstructing a mixed upland and lowland boreal plain ecosystem. The physical construction of the 50 ha area was completed in 2012 and revegetation programs, through planting and seeding, began that same year and continued into 2013. Since then, the vegetation has developed a substantial cover over the reclaimed soil and peat substrates used to cap the engineered topography constructed from mine tailings. To monitor the dynamics of carbon cycling processes in this novel ecosystem, near weekly gas chamber measurements of methane fluxes were carried out over 3 growing seasons. Soil moisture, temperature and ion flux measurements, using Plant Root Simulator probes, were also collected alongside the gas flux plots. In the 3rd season, a transect was established in the lowlands along a moisture gradient to collect continuous reduction-oxidation potential measurements along with these other variables. Overall, methane effluxes remained low relative to what is expected for rewetted organic substrates. However, there is a trend over time towards increasing methane gas emissions that coincides with increasing fluxes of reduced metal ions and decreasing fluxes of sulphate in the fully saturated substrates. The suppressed levels of methane fluxes are possibly due to naturally occurring high levels of sulphate in the donor materials used to cap the ecosystem construction.

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.

Assessing pollution in a Mediterranean lagoon using acid volatile sulfides and estimations of simultaneously extracted metals.

PubMed

Zaaboub, Noureddine; Helali, Mohamed Amine; Martins, Maria Virgínia Alves; Ennouri, Rym; Béjaoui, Béchir; da Silva, Eduardo Ferreira; El Bour, Monia; Aleya, Lotfi

2016-11-01

Bizerte Lagoon is a southern Mediterranean semi-enclosed lagoon with a maximum depth of 12 m. After assessing sediment quality, the authors report on the physicochemical characteristics of the lagoon's surface sediment using SEM (simultaneously extracted metals) and AVS (acid volatile sulfides) as proxies. Biogeochemical tools are used to investigate the environmental disturbance at the water-sediment interface by means of SEM and AVS to seek conclusions concerning the study area's pollution status. Results confirm accumulation of trace elements in sediment. The use of the SEM-AVS model with organic matter in sediment (ƒOC) confirms possible bioavailability of accumulated trace elements, especially Zn, in the southern part of the lagoon, with organic matter playing an important role in SEM excess correction to affirm a nontoxic total metal sediment state. Individual trace element toxicity is dependent on the bioavailable fraction of SEM Metal on sediment, as is the influence of lagoon inflow from southern water sources on element bioavailability. Appropriate management strategies are highly recommended to mitigate any potential harmful effects on health from this heavy-metal-based pollution.

Recent sea-level changes and related engineering problems in the Lagoon of Venice (Italy)

NASA Astrophysics Data System (ADS)

Pirazzoli, Paolo Antonio

In the city of Venice, where the average altitude is only a few tens of centimetres, there has been a dangerous increase in the frequency of flooding during the past few decades. Since 1872, the average increase in flooding levels (“acqua alta”) has been about 40cm: 27cm of this is due to the local rise in mean sea-level (of which some 14cm are related to man-induced subsidence of land, and 3-7cm to geological factors), and at least 14cm are caused by hydrodynamical factors, of which about 10cm can be ascribed to man-induced tidal changes. These latter are due above all to the dredging of deep artificial channels, the reclamation of wide areas of tidal flats, and the diking of fish ponds (“valli”), which have changed the ratio between the surface of the lagoon and that of the inlets. Since the latest modification (1963-1969), the lagoon has been open to large oil tankers, thereby allowing an easier entry of storm surges arising out at sea. Indeed an incompatibility exists between the accessibility of very large boats to the lagoon and the safeguard of Venice. Several engineering projects have been proposed with a view to improving the present critical situation. These projects include underground injections to raise the islands, the construction of new embankments, a reduction in the size of the passes, new access to wide areas for the tide, and the construction of flood gates at the passes. The reliability and effects of these projects are analysed and discussed. In conclusion, the removal of the oil terminal from the lagoon and a stricter control of water pollution are considered the most urgent preliminary actions for a long term solution of the flooding problem. This would enable a decrease in the exchanges between the lagoon and the sea, without, however, reducing the depth of the navigation channels to levels inconsistent with most of the present non-oil traffic. A final measure would be the construction of mobile gates at the passes which would

Recovery of viruses from field samples of raw, digested, and lagoon-dried sludges*

PubMed Central

Sattar, Syed A.; Westwood, J. C. N.

1979-01-01

In a 22-month study, viruses were detected in 84% (62/74) of raw, 53% (19/36) of anaerobically digested, and 39% (11/28) of lagoon-dried sludge samples. Lagoon sludge contained detectable viruses (reovirus and enterovirus groups) even after 8 months of retention. Because of such prolonged virus survival in sludge, care must be taken in its disposal or utilization. PMID:311705

Formation and retention of methane in coal. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 seamsmore » 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.« less

Evaluating the Effects of Surface Properties on Methane Detection with the Airborne Visible/Infrared Imaging Spectrometer Next Generation (AVIRIS-NG)

NASA Astrophysics Data System (ADS)

Ayasse, A.; Thorpe, A. K.; Roberts, D. A.; Aubrey, A. D.; Dennison, P. E.; Thompson, D. R.; Frankenberg, C.

2016-12-01

Atmospheric methane has been increasing since the industrial revolution and is thought to be responsible for about 25% of global radiative forcing (Hofman et al., 2006; Montzka et al., 2011). Given the importance of methane to global climate, it is essential that we identify methane sources to better understand the proportion of emissions coming from various sectors. Recently the Airborne Visible-Infrared Imaging Spectrometer Next Generation (AVIRIS-NG) has proven to be a valuable instrument for mapping methane plumes (Frankenberg et al., 2016; Thorpe et al., 2016; Thompson et al., 2015). However, it is important to determine how land cover and albedo affect the ability of AVIRIS-NG to detect methane. This study aims to quantify the effect these surface properties have on detection. To do so we are using a synthetic AVIRIS-NG image that has multiple land cover types, albedos, and methane concentrations and applying the Cluster Tunes Matched Filter (CTMF) algorithm (Funk et al. 2001, Thorpe et al., 2013) to detect methane enhancements within the image. CTMF results are compared to the surface properties to characterize how different surface properties affect detection. We will also evaluate the effect of surface properties with examples of methane plumes observed from oil fields and manure ponds in the San Joaquin Valley of California, two important methane sources (Figure 1). Initial results suggest that darker surfaces, such as water absent sun glint, will make detecting the methane signal challenging, while bright surfaces such as dry soils produce a much clearer signal. Characterizing the effect of surface properties on methane detection is of increasing importance given the application of this technology will likely expand to map methane across a diverse range of emission sources. Figure 1. AVIRIS-NG image acquired Apr. 29, 2015. True color image with a superimposed methane plume from a manure pond. Bright surfaces, such as the dirt road, provide a better

A new model evaluating Holocene sediment dynamics: Insights from a mixed carbonate-siliciclastic lagoon (Bora Bora, Society Islands, French Polynesia, South Pacific)

NASA Astrophysics Data System (ADS)

Isaack, Anja; Gischler, Eberhard; Hudson, J. Harold; Anselmetti, Flavio S.; Lohner, Andreas; Vogel, Hendrik; Garbode, Eva; Camoin, Gilbert F.

2016-08-01

Mixed carbonate-siliciclastic lagoons of barrier reefs provide great potential as sedimentary archives focusing on paleoenvironmental and paleoclimatic changes as well as on event deposition. Sediment sources include lagoonal carbonate production, the marginal reef and the volcanic hinterland. Mixed carbonate-siliciclastic continent-attached coastal lagoons have been intensively studied, however, their isolated oceanic counterparts have been widely disregarded. Here, we present a new model of Holocene sediment dynamics in the barrier-reef lagoon of Bora Bora based on sedimentological, paleontological, geochronological and geochemical data. The lagoonal succession started with a Pleistocene soil representing the Lowstand Systems Tract. As the rising Holocene sea inundated the carbonate platform, peat accumulated locally 10,650-9400 years BP. Mixed carbonate-siliciclastic sedimentation started ca. 8700-5500 years BP and represents the Transgressive Systems Tract. During that time, sediments were characterized by relatively coarse grain size and contained high amounts of terrestrial material from the volcanic hinterland as well as carbonate sediments mainly produced within the lagoon. Siliciclastic content decreases throughout the Holocene. After the rising sea had reached its modern level, sand aprons formed between reef crest and lagoon creating transport pathways for reef-derived material leading to carbonate-dominated sedimentation ca. 6000-3000 years BP during the Highstand Systems Tract. However, mainly fine material was transported and accumulated in the lagoon while coarser grains were retained on the prograding sand apron. From ca. 4500-500 years BP, significant variations in grain-size, total organic carbon as indicator for primary productivity, Ca and Cl element intensities as qualitative indicators for carbonate availability and lagoonal salinity are seen. Such patterns could indicate event (re-)deposition and correlate with contemporaneous event deposits

Comprehensive assessment of hormones, phytoestrogens, and estrogenic activity in an anaerobic swine waste lagoon

USGS Publications Warehouse

Yost, Erin E.; Meyer, Michael T.; Dietze, Julie E.; Meissner, Benjamin M.; Williams, Mike; Worley-Davis, Lynn; Lee, Boknam; Kullman, Seth W.

2013-01-01

In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were more abundant than androgens or progesterone, with estrone being the predominant estrogen species. Conjugated hormones were detected only at low levels. The isoflavone metabolite equol was by far the predominant phytoestrogen species, with daidzein, genistein, formononetin, and coumestrol present at lower levels. Phytoestrogens were often more abundant than steroidal estrogens, but contributed minimally towards total estrogenic activity. Analytes were significantly elevated in the solid phases of the lagoon; although low observed log KOC values suggest enhanced solubility in the aqueous phase, perhaps due to dissolved or colloidal organic carbon. The association with the solid phase, as well as recalcitrance of analytes to anaerobic degradation, results in a markedly elevated load of analytes and estrogenic activity within lagoon sludge. Overall, findings emphasize the importance of adsorption and transformation processes in governing the fate of these compounds in lagoon waste, which is ultimately used for broadcast application as a fertilizer.

Comprehensive Assessment of Hormones, Phytoestrogens, and Estrogenic Activity in an Anaerobic Swine Waste Lagoon

PubMed Central

2013-01-01

In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were more abundant than androgens or progesterone, with estrone being the predominant estrogen species. Conjugated hormones were detected only at low levels. The isoflavone metabolite equol was by far the predominant phytoestrogen species, with daidzein, genistein, formononetin, and coumestrol present at lower levels. Phytoestrogens were often more abundant than steroidal estrogens, but contributed minimally toward total estrogenic activity. Analytes were significantly elevated in the solid phases of the lagoon; although low observed log KOC values suggest enhanced solubility in the aqueous phase, perhaps due to dissolved or colloidal organic carbon. The association with the solid phase, as well as recalcitrance of analytes to anaerobic degradation, results in a markedly elevated load of analytes and estrogenic activity within lagoon sludge. Overall, findings emphasize the importance of adsorption and transformation processes in governing the fate of these compounds in lagoon waste, which is ultimately used for broadcast application as a fertilizer. PMID:24144340

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.

Dissolved Copper, Nickel and Lead in Tampamachoco Lagoon and Tuxpan River Estuary in the SW Gulf of Mexico.

PubMed

Garduño Ruiz, E P; Rosales Hoz, L; Carranza Edwards, A

2016-10-01

In order to estimate the effects of a thermal power plant, physicochemical parameters and the concentrations of copper, nickel and lead were evaluated in water from both Tampamachoco Lagoon and the estuary of the Tuxpan River. Average salinities were 33.66 ups in the lagoon area, 32.77 ups in the channel that joins the lagoon and the river, and 24.74 ups in the river estuary. Total average metal concentrations were 21.95 for Cu, 29.67 for Ni and 4.31 µ/L for Pb. Sampling point 1 and samples from the bottom water of the lagoon present the highest salinities and concentrations of suspended matter, TOC, Cu, Ni and Pb.These high values may be associated with the infiltration of sea water either from plant operation or from the channel that connects the lagoon with the sea.

Methane production and consumption in an active volcanic environment of Southern Italy.

PubMed

Castaldi, Simona; Tedesco, Dario

2005-01-01

Methane fluxes were measured, using closed chambers, in the Crater of Solfatara volcano, Campi Flegrei (Southern Italy), along eight transects covering areas of the crater presenting different landscape physiognomies. These included open bare areas, presenting high geothermal fluxes, and areas covered by vegetation, which developed along a gradient from the central open area outwards, in the form of maquis, grassland and woodland. Methane fluxes decreased logarithmically (from 150 to -4.5 mg CH4 m(-2)day(-1)) going from the central part of the crater (fangaia) to the forested edges, similarly to the CO2 fluxes (from 1500 g CO2 m(-2)day(-1) in the centre of the crater to almost zero flux in the woodlands). In areas characterized by high emissions, soil presented elevated temperature (up to 70 degrees C at 0-10 cm depth) and extremely low pH (down to 1.8). Conversely, in woodland areas pH was higher (between 3.7 and 5.1) and soil temperature close to air values. Soil (0-10 cm) was sampled, in two different occasions, along the eight transects, and was tested for methane oxidation capacity in laboratory. Areas covered by vegetation mostly consumed CH4 in the following order woodland>macchia>grassland. Methanotrophic activity was also measured in soil from the open bare area. Oxidation rates were comparable to those measured in the plant covered areas and were significantly correlated with field CH4 emissions. The biological mechanism of uptake was demonstrated by the absence of activity in autoclaved replicates. Thus results suggest the existence of a population of micro-organisms adapted to this extreme environment, which are able to oxidize CH4 and whose activity could be stimulated and supported by elevated concentrations of CH4.

Identifying tsunami deposits using shell taphonomy: Sur lagoon, Oman

NASA Astrophysics Data System (ADS)

Donato, S.; Reinhardt, E.; Rothaus, R.; Boyce, J.

2007-05-01

On November 28th, 1945 an 8.1 magnitude earthquake focused in the eastern portion of the Makran subduction zone (Arabian Sea) generated a powerful tsunami that destroyed many coastal villages in Pakistan and India. Reports indicate that the tsunami also caused significant damage in Muscat, Oman, although its effects elsewhere in Oman are unknown. A thick bivalve dominated shell horizon was discovered inside the Sur lagoon, which is located on the eastern promontory of Oman (200 km south of Muscat). This shell deposit is significant because it is laterally extensive (> 1 km2), extends deep within the lagoon (>2 km), ranges in thickness from 5 - 25 cm at the sample localities, contains numerous subtidal and offshore bivalve species, and articulated subtidal and offshore bivalve species are abundant. Although there is an absence of typical tsunami indicators such as allochthonous sediment in and around the lagoon, verbal accounts, cultural evidence recovered during coring, and the absence of strong storms during the past 100 years indicates that this shell unit was caused by the 1945 tsunami. In this setting, it would be advantageous to have another proxy for tsunami detection and risk prediction. The use of shell taphonomy is one of the potential indicators and here we present new evidence of its utility. We sampled this unit in eight locations, and compared the shell taphonomy to surface shell samples collected from beach and reworked horizons in the lagoon, and to shell samples from a known tsunami and corresponding storm/ballast deposit in Israel (Reinhardt et al., 2006). Taphonomic analysis yielded promising results, as the two tsunami horizons shared excellent agreement between the amount of fragmented shells, and the percentage of shells displaying angular breaks. Both of these categories were significantly different from the percentage of fragments and angular fragments recovered from the reworked, beach, and storm/ballast deposits, indicating different

Benthic foraminiferal and organic matter compounds as proxies of environmental quality in a tropical coastal lagoon: The Itaipu lagoon (Brazil).

PubMed

Raposo, Débora; Clemente, Iara; Figueiredo, Marcos; Vilar, Amanda; Lorini, Maria Lucia; Frontalini, Fabrizio; Martins, Virgínia; Belart, Pierre; Fontana, Luiz; Habib, Renan; Laut, Lazaro

2018-04-01

Lagoons in the southeast coast of Brazil have experienced eutrophication due to the exponential increase of human population and sewage discharges. Living benthic foraminifera have demonstrated to be good bioindicators of such impacts. This study aims to evaluate the organic matter accumulation effects on the foraminiferal distribution in the Itaipu lagoon (Brazil). On the basis of the biotic and abiotic analyses, three sectors are identified. The Sector I, an inner area, is characterized by high dissolved oxygen values and foraminiferal species with preference for marine conditions, demonstrating the sea influence. The Sector II, in the mangrove margins, is associated to sandy sediment and biopolymers and mainly represented by euryhaline species. The Sector III is marked by low density or absence of living foraminifera and corresponds to a low quality organic matter enriched area (North, Southwest and Centre). Copyright © 2018 Elsevier Ltd. All rights reserved.

Inverse Modeling of Tropospheric Methane Constrained by 13C Isotope in Methane

NASA Astrophysics Data System (ADS)

Mikaloff Fletcher, S. E.; Tans, P. P.; Bruhwiler, L. M.

2001-12-01

Understanding the budget of methane is crucial to predicting climate change and managing earth's carbon reservoirs. Methane is responsible for approximately 15% of the anthropogenic greenhouse forcing and has a large impact on the oxidative capacity of Earth's atmosphere due to its reaction with hydroxyl radical. At present, many of the sources and sinks of methane are poorly understood, due in part to the large spatial and temporal variability of the methane flux. Model calculations of methane mixing ratios using most process-based source estimates typically over-predict the inter-hemispheric gradient of atmospheric methane. Inverse models, which estimate trace gas budgets by using observations of atmospheric mixing ratios and transport models to estimate sources and sinks, have been used to incorporate features of the atmospheric observations into methane budgets. While inverse models of methane generally tend to find a decrease in northern hemisphere sources and an increase in southern hemisphere sources relative to process-based estimates,no inverse study has definitively associated the inter-hemispheric gradient difference with a specific source process or group of processes. In this presentation, observations of isotopic ratios of 13C in methane and isotopic signatures of methane source processes are used in conjunction with an inverse model of methane to further constrain the source estimates of methane. In order to investigate the advantages of incorporating 13C, the TM3 three-dimensional transport model was used. The methane and carbon dioxide measurements used are from a cooperative international effort, the Cooperative Air Sampling Network, lead by the Climate Monitoring Diagnostics Laboratory (CMDL) at the National Oceanic and Atmospheric Administration (NOAA). Experiments using model calculations based on process-based source estimates show that the inter-hemispheric gradient of δ 13CH4 is not reproduced by these source estimates, showing that the

Liquid and atmospheric ammonia concentrations from a dairy lagoon during an aeration experiment

NASA Astrophysics Data System (ADS)

Rumburg, Brian; Neger, Manjit; Mount, George H.; Yonge, David; Filipy, Jenny; Swain, John; Kincaid, Ron; Johnson, Kristen

Ammonia emissions from agriculture are an environmental and human health concern, and there is increasing pressure to reduce emissions. Animal agriculture is the largest global source of ammonia emissions and on a per cow basis dairy operations are the largest emitters. The storage and disposal of the dairy waste is one area where emissions can be reduced, aerobic biological treatment of wastewater being a common and effective way of reducing ammonia emissions. An aeration experiment in a dairy lagoon with two commercial aerators was performed for 1 month. Liquid concentrations of ammonia, total nitrogen, nitrite and nitrate were monitored before, during and after the experiment and atmospheric ammonia was measured downwind of the lagoon using a short-path differential optical absorption spectroscopy (DOAS) instrument with 1 ppbv sensitivity. No changes in either liquid or atmospheric ammonia concentrations were detected throughout the experiment, and neither dissolved oxygen, nitrite nor nitrate could be detected in the lagoon at any time. The average ammonia concentration at 10 sampling sites in the lagoon at a depth of 0.15 m was 650 mg l -1 and at 0.90 m it was 700 mg l -1 NH 3-N. The average atmospheric ammonia concentration 50 m downwind was about 300 ppbv. The 0.90 m depth total nitrogen concentrations and total and volatile solids concentrations decreased during the experiment due to some mixing of the lagoon but the 0.15 m depth concentrations did not decrease indicating that the aerators were not strong enough to mix the sludge off the bottom into the whole water column.

Monodeuterated Methane, an Isotopic Tool To Assess Biological Methane Metabolism Rates

PubMed Central

Steele, Joshua A.; Ziebis, Wiebke; Scheller, Silvan; Case, David; Reynard, Linda M.; Orphan, Victoria J.

2017-01-01

ABSTRACT Biological methane oxidation is a globally relevant process that mediates the flux of an important greenhouse gas through both aerobic and anaerobic metabolic pathways. However, measuring these metabolic rates presents many obstacles, from logistical barriers to regulatory hurdles and poor precision. Here we present a new approach for investigating microbial methane metabolism based on hydrogen atom dynamics, which is complementary to carbon-focused assessments of methanotrophy. The method uses monodeuterated methane (CH3D) as a metabolic substrate, quantifying the aqueous D/H ratio over time using off-axis integrated cavity output spectroscopy. This approach represents a nontoxic, comparatively rapid, and straightforward approach that supplements existing radiotopic and stable carbon isotopic methods; by probing hydrogen atoms, it offers an additional dimension for examining rates and pathways of methane metabolism. We provide direct comparisons between the CH3D procedure and the well-established 14CH4 radiotracer method for several methanotrophic systems, including type I and II aerobic methanotroph cultures and methane-seep sediment slurries and carbonate rocks under anoxic and oxic incubation conditions. In all applications tested, methane consumption values calculated via the CH3D method were directly and consistently proportional to 14C radiolabel-derived methane oxidation rates. We also employed this method in a nontraditional experimental setup, using flexible, gas-impermeable bags to investigate the role of pressure on seep sediment methane oxidation rates. Results revealed an 80% increase over atmospheric pressure in methanotrophic rates the equivalent of ~900-m water depth, highlighting the importance of this parameter on methane metabolism and exhibiting the flexibility of the newly described method. IMPORTANCE Microbial methane consumption is a critical component of the global carbon cycle, with wide-ranging implications for climate regulation

Monodeuterated Methane, an Isotopic Tool To Assess Biological Methane Metabolism Rates.

PubMed

Marlow, Jeffrey J; Steele, Joshua A; Ziebis, Wiebke; Scheller, Silvan; Case, David; Reynard, Linda M; Orphan, Victoria J

2017-01-01

Biological methane oxidation is a globally relevant process that mediates the flux of an important greenhouse gas through both aerobic and anaerobic metabolic pathways. However, measuring these metabolic rates presents many obstacles, from logistical barriers to regulatory hurdles and poor precision. Here we present a new approach for investigating microbial methane metabolism based on hydrogen atom dynamics, which is complementary to carbon-focused assessments of methanotrophy. The method uses monodeuterated methane (CH 3 D) as a metabolic substrate, quantifying the aqueous D/H ratio over time using off-axis integrated cavity output spectroscopy. This approach represents a nontoxic, comparatively rapid, and straightforward approach that supplements existing radiotopic and stable carbon isotopic methods; by probing hydrogen atoms, it offers an additional dimension for examining rates and pathways of methane metabolism. We provide direct comparisons between the CH 3 D procedure and the well-established 14 CH 4 radiotracer method for several methanotrophic systems, including type I and II aerobic methanotroph cultures and methane-seep sediment slurries and carbonate rocks under anoxic and oxic incubation conditions. In all applications tested, methane consumption values calculated via the CH 3 D method were directly and consistently proportional to 14 C radiolabel-derived methane oxidation rates. We also employed this method in a nontraditional experimental setup, using flexible, gas-impermeable bags to investigate the role of pressure on seep sediment methane oxidation rates. Results revealed an 80% increase over atmospheric pressure in methanotrophic rates the equivalent of ~900-m water depth, highlighting the importance of this parameter on methane metabolism and exhibiting the flexibility of the newly described method. IMPORTANCE Microbial methane consumption is a critical component of the global carbon cycle, with wide-ranging implications for climate regulation

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 ...

Influence of operating pressure on the biological hydrogen methanation in trickle-bed reactors.

PubMed

Ullrich, Timo; Lindner, Jonas; Bär, Katharina; Mörs, Friedemann; Graf, Frank; Lemmer, Andreas

2018-01-01

In order to investigate the influence of pressures up to 9bar absolute on the productivity of trickle-bed reactors for biological methanation of hydrogen and carbon dioxide, experiments were carried out in a continuously operated experimental plant with three identical reactors. The pressure increase promises a longer residence time and improved mass transfer of H 2 due to higher gas partial pressures. The study covers effects of different pressures on important parameters like gas hourly space velocity, methane formation rate, conversion rates and product gas quality. The methane content of 64.13±3.81vol-% at 1.5bar could be increased up to 86.51±0.49vol-% by raising the pressure to 9bar. Methane formation rates of up to 4.28±0.26m 3 m -3 d -1 were achieved. Thus, pressure increase could significantly improve reactor performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Diazotroph community succession during the VAHINE mesocosms experiment (New Caledonia Lagoon)

NASA Astrophysics Data System (ADS)

Turk-Kubo, K. A.; Frank, I. E.; Hogan, M. E.; Desnues, A.; Bonnet, S.; Zehr, J. P.

2015-06-01

The VAHINE mesocosm experiment, conducted in the low-nutrient low-chlorophyll waters of the Noumea Lagoon (coastal New Caledonia) was designed to trace the incorporation of nitrogen (N) fixed by diazotrophs into the food web, using large volume (50 m3) mesocosms. This experiment provided a unique opportunity to study the succession of different N2-fixing microorganisms (diazotrophs) and calculate in situ net growth and loss rates in response to fertilization with dissolved inorganic phosphate (DIP) over a 23 day period, using quantitative polymerase chain reaction (qPCR) assays. Inside the mesocosms, the diazotroph community assemblage was dominated by the heterocyst-forming Richelia associated with Rhizosolenia (Het-1) in the first half of the experiment, and unicellularcyanobacterial Group C (UCYN-C) became the dominant diazotroph in the second half of the experiment. Decreasing DIP concentrations following the fertilization event and increasing temperatures were significantly correlated with increasing abundances of UCYN-C. Maximum net growth rates for UCYN-C were calculated to be between 1.23 ± 0.07 and 2.16 ± 0.07 d-1 which are among the highest growth rates reported for diazotrophs. Outside the mesocosms in the Noumea Lagoon, UCYN-C abundances remained low, despite increasing temperatures, suggesting that the microbial community response to the DIP fertilization created conditions favorable for UCYN-C growth inside the mesocosms. Maximum net growth and loss rates for nine diazotroph phylotypes throughout the 23 day experiment were variable between mesocosms, and repeated fluctuations between periods of net growth and loss were commonly observed. The field population of diazotrophs in the Noumea Lagoon, was dominated by Het-1 over the course of the study period. However, eight additional diazotroph phylotypes were present in the lagoon at lower abundances, indicating a diverse field population of diazotrophs. Two ecotypes of the Braarudosphaera bigelowii

Macrobenthic molluscs from a marine - lagoonal environmental transition in Lesvos Island (Greece).

PubMed

Evagelopoulos, Athanasios; Koutsoubas, Drosos; Gerovasileiou, Vasilis; Katsiaras, Nikolaos

2016-01-01

This paper describes an occurence dataset, also including numerical abundance and biomass data, pertaining to the macrobenthic molluscan assemblages from a marine - lagoonal environmental transition. The study system was the soft-substrate benthoscape of the area of the Kalloni solar saltworks (Lesvos Island, Greece). Specifically, the study area extended from the infralittoral zone of the inner Kalloni Gulf (marine habitat) to the bottoms of the first two evaporation ponds of the Kalloni solar saltworks (lagoonal habitat). Bottom sediment samples (3 replicates) were collected with a Van Veen grab sampler (0.1 m 2 ) at four sampling sites, along a 1.5 km long line transect that spanned the marine - lagoonal environmental transition. A total of four surveys were carried out seasonally in 2004.  A total of 39,345 molluscan individuals were sorted out of the sediment samples and were identified to 71 species, belonging to the Gastropoda (36), Bivalvia (34) and Scaphopoda (1) classes. Numerical abundance and wet biomass (with shells) data are included in the dataset. The dataset described in the present paper partially fills a significant gap in the scientific literature: Because ecological research of coastal lagoons has seldom explicitly considered the marine - lagoonal habitats interface, there are no openly accessible datasets pertaining to the particular structural component of the transitional waters benthoscapes of the Mediterranean Sea. Such datasets could prove valuable in the research of the structure and functioning of transitional waters benthoscapes. The present dataset is available as a supplementary file (Suppl. material 1) and can also be accessed at http://ipt.medobis.eu/resource?r=kalloni_saltworks_phd.

Harnessing methane

NASA Astrophysics Data System (ADS)

Showstack, Randy

The total methane resource in hydrates—ice-like substances found in deep ocean sediments and Arctic permafrost—exceeds the energy content of all other fossil fuel resources,such as coal, oil, and conventional gas, according to the U.S. Geological Survey (USGS).The Methane Hydrate Research and Development Act, signed into law by U.S. President Bill Clinton on May 3, establishes a new federal commitment to developing methane hydrates, which has been touted as a potentially clean energy source that could make the U.S. less dependent on foreign sources of energy. The bill authorizes $47.5 million over five years for the Department of Energy to establish a federal methane hydrate research and development program.

Atoll-phosphate genesis: Role of lagoonal biomass and possible role of endo-upwelling processes in phosphate concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trichet, J.; Rougerie, F.

1990-06-01

Sedimentological and hydrogeological data in Niau, a closed atoll in French Polynesia where P-concentration has been measured, suggest the role played by lagoonal organic matter in P-accumulation and the possible role of endo-upwelling processes in P-input in the system. A 15 m deep core through the lagoonal deposits shows the succession of organic-rich strata in which the P-content can reach up to 1.3% P{sub 2}O{sub 5}. Such a pattern suggests that, whatever the source of P within the lagoon (lagoonal water, bird guano, or endo-upwelled solutions, see below), this element is likely to be incorporated in quantitatively important lagoonal biomassmore » whose decay releases phosphorus back to the sediment. An example of such biomass and organic matter is given by the large amounts of cyano-bacterial organic matter that are present in the lagoon of Niau. A source for island phosphate has recently been proposed to be relatively deep seawater, which would be endo-upwelled from depths of hundreds of meters ({approximately}500 m, where P content is approximately 1.5 mmol.m{sup {minus}3} PO{sub 4}-P) through the permeable reef-body up to its surface (i.e., to its lagoonal waters, where P content reaches 5 mmol.m{sup {minus}3} in Niau atoll). The energy necessary for the transport of such solutions would be geothermal (at the bottom of the water column, i.e., close to the volcanic substrate of the reef body) and solar at its top through evaporation.« less

Tet and sul antibiotic resistance genes in livestock lagoons of various operation type, configuration, and antibiotic occurrence

USGS Publications Warehouse

McKinney, C.W.; Loftin, K.A.; Meyer, M.T.; Davis, J.G.; Pruden, A.

2010-01-01

Although livestock operations are known to harbor elevated levels of antibiotic resistant bacteria, few studies have examined the potential of livestock waste lagoons to reduce antibiotic resistance genes (ARGs). The purpose of this study was to determine the prevalence and examine the behavior of tetracycline [tet(O) and tet(W)] and sulfonamide [sul(I) and su/(II)] ARGsin a broad cross-section of livestock lagoons within the same semiarid western watershed. ARGs were monitored for one year in the water and the settled solids of eight lagoon systems by quantitative polymerase chain reaction. In addition, antibiotic residues and various bulk water quality constituents were analyzed. It was found that the lagoons of the chicken layer operation had the lowest concentrations of both tet and sul ARGs and low total antibiotic concentrations, whereas su ARGs were highest in the swine lagoons, which generally corresponded to the highest total antibiotic concentrations. A marginal benefit of organic and small dairy operations also was observed compared to conventional and large dairies, respectively. In all lagoons, su ARGs were observed to be generally more recalcitrant than tet ARGs. Also, positive correlations of various bulk water quality constituents were identified with tet ARGs but not sul ARGs. Significant positive correlations were identified between several metals and tet ARGs, but Pearson's correlation coefficients were mostly lower than those determined between antibiotic residues and ARGs. This study represents a quantitative characterization of ARGs in lagoons across a variety of livestock operations and provides insight into potential options for managing antibiotic resistance emanating from agricultural activities. ?? 2010 American Chemical Society.

Environmental changes in the Moulay Bousselham lagoon (Morocco) during the last 7 000 years using a multiproxy approach

NASA Astrophysics Data System (ADS)

Zourarah, Bendahhou; Maanan, Mohamed; Conceição Freitas, Maria; Leroy, Suzanne; Andrade, César; Cearreta, Alejandro; Cruces, Anabela

2016-04-01

The aim of this research is to reconstruct Holocene environmental changes in Moulay Bousselham lagoon using a multi-proxy approach to the study of sediments of two short cores: biological (e.g., pollen, foraminifera and diatoms), physicochemical (isotopes, chemical composition) and sedimentary (grain size, clay minerals). The research highlights the role of climatic variations and human interference in the evolution of this lagoon. The results show that at the beginning of the Holocene this area corresponded to a wide coastal bay, including the surface of Moulay Bousselham present-day lagoon and Merja Ras Ed-Dora. The dating's obtained in the base of the sediment cores range from 6790-6640 BP (end of the Atlantic and early Sub-boreal). Sand predominates in this section of the cores, with low content of organic matter and high content of bioclasts. Ammonia tepida is the predominant species but Haynesina germânica, Quinqueloculina semínula,Cibicides lobatulus,Criboelphidium oceanensis and Miliolinella sobrotunda are also presente. At the base, foraminifera assemblages show a relative abundance of Planorbulina mediterranensis, Rosalina anomala, Rosalina irregularis, Miliolinella subrotunda and Cibicides lobatulus. These are typical of a shallow environment with normal marine salinity. During the sub-boreal period (6640-4520 BP), a sandy barrier developed and the lagoon evolved to a brackish lagoon with low salinity. Sedimentation is homogeneous, the content of silt and clay is high (90%), calcium carbonate content is usually lower than 20% and the organic material exhibited the highest values (> 10%). Ammonia tepida is also the dominant species but C. oceanensis and H. germanica are secondary. The lagoon was closed in drier conditions and has gradually filled by sediments coming from the watershed, represented by an illite-chlorite association. The lagoon evolved to a sabkha. We must emphasize the role of deforestation caused by the Romans (2100 BP) in that period

Consumption of methane by soils.

PubMed

Dueñas, C; Fernández, M C; Carretero, J; Pérez, M; Liger, E

1994-05-01

Measurements of the methane flux and methane concentration profiles in soil air are presented. The flux of methane from the soil is calculated by two methods: a) Direct by placing a static open chamber at the soil surface. b) Indirect, using the (222)Rn concentrations profile and the (222)Rn flux in the soil surface in parallel with the methane concentration ((222)Rn calibrated fluxes). The methane flux has been determined in two kinds of soils (sandy and loamy) in the surroundings of Málaga (SPAIN). The directly measured methane fluxes at all investigated sites is higher than methane fluxes derived from "Rn calibrated fluxes". Atmospheric methane is consumed by soils, mean direct flux to the atmosphere were - 0.33 g m(-2)yr-1. The direct methane flux is the same within the measuring error in sandy and loamy soils. The influence of the soil parameters on the methane flux indicates that microbial decomposition of methane is primarily controlled by the transport of methane.

Ecosystem Modelling for Impact Assessment of Possible Methane Leakage during Methane Hydrate Utilization

NASA Astrophysics Data System (ADS)

Yamazaki, T.; Nakano, Y.; Monoe, D.; Oomi, T.; Doi, T.; Nakata, K.; Fukushima, T.

2005-05-01

Natural methane hydrate has been scientifically studied as a carbon reservoir globally. However, in Japan, the potential for energy resource has been industrially highlighted. There is less domestic oil and natural gas resources in Japan, but many potential deposition areas for methane hydrate in ocean around Japan are the reasons. Less CO2 discharge from methane compared with coal, oil and conventional natural gas when the same calorie value we get is considered as the advantage for energy resource. However, because methane hydrate distributes in shallower sediment layer in ocean floor, accidental leakage of methane may occur while we utilize methane hydrate. Methane itself has 21-times impact on the greenhouse effect, if it reaches the atmosphere. Therefore, it is necessary to estimate the behavior in the environment after the leakage, if we want to use methane hydrate as energy resource. The mass balance after leakage of methane on seafloor and in water column is numerically studied through the analyses of methane emissions from natural cold seepages and hydrothermal activities in this research. The outline structure of mass balance ecosystem model creating is introduced and some preliminary examination results from the test calculation are discussed.

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.

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

PubMed

Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Hoefman, Sven; De Vos, Paul; Boeckx, Pascal; Boon, Nico

2014-04-01

Biological treatment using methane-oxidizing bacteria (MOB) immobilized on six porous carrier materials have been used to mitigate methane emission. Experiments were performed with different MOB inoculated in building materials at high (~20 % (v/v)) and low (~100 ppmv) methane mixing ratios. Methylocystis parvus in autoclaved aerated concrete (AAC) exhibited the highest methane removal rate at high (28.5 ± 3.8 μg CH₄ g⁻¹ building material h⁻¹) and low (1.7 ± 0.4 μg CH₄ g⁻¹ building material h⁻¹) methane mixing ratio. Due to the higher volume of pores with diameter >5 μm compared to other materials tested, AAC was able to adsorb more bacteria which might explain for the higher methane removal observed. The total methane and carbon dioxide-carbon in the headspace was decreased for 65.2 ± 10.9 % when M. parvus in Ytong was incubated for 100 h. This study showed that immobilized MOB on building materials could be used to remove methane from the air and also act as carbon sink.

A new method to study simultaneous methane oxidation and methane production in soils

NASA Astrophysics Data System (ADS)

Andersen, B. L.; Bidoglio, G.; Leip, A.; Rembges, D.

1998-12-01

Results of laboratory experiments show that 14C-labeled methane added to soil was consumed faster than atmospheric 12C methane. This implies a source of methane, presumably through methanogenesis, in a soil that is a net consumer of atmospheric methane. The soil was well-drained forest soil from Ispra, Italy. An undisturbed sample was taken with a steel corer and incubated under oxic conditions in a jar. Headspace samples were taken at time intervals and analyzed for total methane by gas chromatography and analyzed for 14C methane by liquid scintillation counting. Fluxes calculated from the decreasing headspace mixing ratios were, for example, -6.5 and -7.1 μmol m-2 hr-1 for 12C methane and 14C methane, respectively. A simple model is considered which reproduces reasonably well the observed mixing ratios as function of time.

The structure and productivity of the Thalassia testudinum community in Bon Accord Lagoon, Tobago.

PubMed

Juman, Rahanna A

2005-05-01

The Thalassia testudinum dominated seagrass community in the Buccoo Reef/ Bon Accord Lagoon Marine Park, measures 0.5 km(2) and is part of a contiguous coral reef, seagrass bed and mangrove swamp system in southwest Tobago. 7 testudinum coverage, productivity and percent turnover rates were measured from February 1998 to February 1999 at four sample locations, while total T. testudinum biomass was measured at two locations in the lagoon from 1992-2002. Productivity and turnover rates varied spatially and seasonally. They were higher in the back-reef area than in the mangrove-fringed lagoon, and were lowest at locations near to a sewage outfall. 7 testudinum coverage ranged from 6.6% in the lagoon to 68.5% in the back-reef area while productivity ranged from 3.9 to 4.9 g dry wt m(-2) d(-1) . Productivity and percentage turnover rates were higher in the dry season (January-June) than in the wet season (July-December). Productivity ranged from 3.0 in the wet season to 5.0 g dry wt m2 d-' in the dry season while percentage turnover rates ranged from 4.2% to 5.6%. Total Thalassia biomass and productivity in Bon Accord Lagoon were compared to six similar sites in the Caribbean that also participate in the Caribbean Coastal Marine Productivity Program (CARICOMP). This seagrass community is being negatively impacted by nutrient-enriched conditions.

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.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

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.

Characterizing reduced sulfur compounds and non-methane volatile organic compounds emissions from a swine concentrated animal feeding operation

NASA Astrophysics Data System (ADS)

Rumsey, Ian Cooper

Reduced sulfur compounds (RSCs) and non-methane volatile organic compounds (NMVOCs) emissions from concentrated animal feeding operations (CAFOs) have become a potential environmental and human health concern. Both RSCs and NMVOCs contribute to odor. In addition, RSCs also have the potential to form fine particulate matter (PMfine) and NMVOCs the potential to form ozone. Measurements of RSCs and NMVOCs emissions were made from both an anaerobic lagoon and barn at a swine CAFO in North Carolina. Emission measurements were made over all four seasonal periods. In each seasonal period, measurements were made from both the anaerobic lagoon and barn for ˜1 week. RSC and NMVOCs samples were collected using passivated canisters. Nine to eleven canister samples were taken from both the lagoon and barn over each sampling period. The canisters were analyzed ex-situ using gas chromatography flame ionization detection (GC-FID). Hydrogen sulfide (H2S) measurements were made in-situ using a pulsed fluorescence H2S/SO2 analyzer. During sampling, measurements of meteorological and physiochemical parameters were made. H2S had the largest RSC flux, with an overall average lagoon flux of 1.33 mug m-2 min-1. The two main RSCs identified by the GC-FID, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), had overall average lagoon fluxes an order of magnitude lower, 0.12 and 0.09 mug m-2 min-1, respectively. Twelve significant NMVOCs were identified in lagoon samples (ethanol, 2-ethyl-1-hexanol, methanol, acetaldehyde, decanal, heptanal, hexanal, nonanal, octanal, acetone, methyl ethyl ketone, and 4-methylphenol). The overall average fluxes for these NMVOCs, ranged from 0.08 mug m-2 min-1 (4-methylphenol) to 2.11 mug m-2 min-1 (acetone). Seasonal H2S barn concentrations ranged from 72-631 ppb. DMS and DMDS seasonal concentrations were 2-3 orders of magnitude lower. There were six significant NMVOCs identified in barn samples (methanol, ethanol, acetone 2-3 butanedione, acetaldehyde

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. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

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.

Methane and nitrous oxide emissions from municipal wastewater treatment - results from a long-term study.

PubMed

Daelman, M R J; van Voorthuizen, E M; van Dongen, L G J M; Volcke, E I P; van Loosdrecht, M C M

2013-01-01

Methane and nitrous oxide emissions from a fully covered municipal wastewater treatment plant were measured on-line during 16 months. At the plant under study, nitrous oxide contributed three-quarters to the plant's carbon footprint, while the methane emission was slightly larger than the indirect carbon dioxide emission related to the plant's electricity and natural gas consumption. This contrasted with two other wastewater treatment plants, where more than 80% of the carbon footprint came from the indirect carbon dioxide emission. The nitrous oxide emission exhibited a seasonal dynamic, of which the cause remains unclear. Three types of air filter were investigated with regard to their effectiveness to remove methane from the off-gas.

Attribution of changes in global wetland methane emissions from pre-industrial to present using CLM4.5-BGC

DOE PAGES

Paudel, Rajendra; Mahowald, Natalie M.; Hess, Peter G. M.; ...

2016-03-10

An understanding of potential factors controlling methane emissions from natural wetlands is important to accurately project future atmospheric methane concentrations. Here, we examine the relative contributions of climatic and environmental factors, such as precipitation, temperature, atmospheric CO 2 concentration, nitrogen deposition, wetland inundation extent, and land-use and land-cover change, on changes in wetland methane emissions from preindustrial to present day (i.e., 1850-2005). We apply a mechanistic methane biogeochemical model integrated in the Community Land Model version 4.5 (CLM4.5), the land component of the Community Earth System Model. The methane model explicitly simulates methane production, oxidation, ebullition, transport through aerenchyma ofmore » plants, and aqueous and gaseous diffusion. We conduct a suite of model simulations from 1850 to 2005, with all changes in environmental factors included, and sensitivity studies isolating each factor. Globally, we estimate that preindustrial methane emissions were higher by 10% than present-day emissions from natural wetlands, with emissions changes from preindustrial to the present of +15%, -41%, and -11% for the high latitudes, temperate regions, and tropics, respectively. The most important change is due to the estimated change in wetland extent, due to the conversion of wetland areas to drylands by humans. This effect alone leads to higher preindustrial global methane fluxes by 33% relative to the present, with the largest change in temperate regions (+80%). These increases were partially offset by lower preindustrial emissions due to lower CO 2 levels (10%), shifts in precipitation (7%), lower nitrogen deposition (3%), and changes in land-use and land-cover (2%). Cooler temperatures in the preindustrial regions resulted in our simulations in an increase in global methane emissions of 6% relative to present day. Much of the sensitivity to these perturbations is mediated in the model by

Attribution of changes in global wetland methane emissions from pre-industrial to present using CLM4.5-BGC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paudel, Rajendra; Mahowald, Natalie M.; Hess, Peter G. M.

An understanding of potential factors controlling methane emissions from natural wetlands is important to accurately project future atmospheric methane concentrations. Here, we examine the relative contributions of climatic and environmental factors, such as precipitation, temperature, atmospheric CO 2 concentration, nitrogen deposition, wetland inundation extent, and land-use and land-cover change, on changes in wetland methane emissions from preindustrial to present day (i.e., 1850-2005). We apply a mechanistic methane biogeochemical model integrated in the Community Land Model version 4.5 (CLM4.5), the land component of the Community Earth System Model. The methane model explicitly simulates methane production, oxidation, ebullition, transport through aerenchyma ofmore » plants, and aqueous and gaseous diffusion. We conduct a suite of model simulations from 1850 to 2005, with all changes in environmental factors included, and sensitivity studies isolating each factor. Globally, we estimate that preindustrial methane emissions were higher by 10% than present-day emissions from natural wetlands, with emissions changes from preindustrial to the present of +15%, -41%, and -11% for the high latitudes, temperate regions, and tropics, respectively. The most important change is due to the estimated change in wetland extent, due to the conversion of wetland areas to drylands by humans. This effect alone leads to higher preindustrial global methane fluxes by 33% relative to the present, with the largest change in temperate regions (+80%). These increases were partially offset by lower preindustrial emissions due to lower CO 2 levels (10%), shifts in precipitation (7%), lower nitrogen deposition (3%), and changes in land-use and land-cover (2%). Cooler temperatures in the preindustrial regions resulted in our simulations in an increase in global methane emissions of 6% relative to present day. Much of the sensitivity to these perturbations is mediated in the model by

Wind effects on prey availability: How northward migrating waders use brackish and hypersaline lagoons in the sivash, Ukraine

NASA Astrophysics Data System (ADS)

Verkuil, Yvonne; Koolhaas, Anita; Van Der Winden, Jan

Large numbers of waders migrating northward in spring use the Sivash, a large system of shallow, brackish and hypersaline lagoons in the Black Sea and Azov Sea region (Ukraine). The bottoms of these lagoons are often uncovered by the wind. Hence, for waders the time and space available for feeding depend on wind conditions. In hypersaline lagoons the benthic and pelagic fauna was very poor, consisting mainly of chironomid larvae (0.19 g AFDM·m -2) and brine shrimps Artemia salina, respectively. Brine shrimp abundance was correlated with salinity, wind force, wind direction and water depth. Dunlin Calidris alpina and curlew sandpiper Calidris ferruginea were the only species feeding on brine shrimp. As brine shrimp densities are higher in deeper water, smaller waders such as broad-billed sandpipers Limicola falcinellus are too short-legged to reach exploitable densities of brine shrimp. In brackish lagoons the benthic and pelagic fauna was rich, consisting of polychaetes, bivalves, gastropods, chironomid larvae, isopods and amphipods (8.9 to 30.5 g AFDM·m -2), but there were no brine shrimps. Prey biomass increased with the distance from the coast, being highest on the site that was most frequently inundated. Dunlin, broad-billed sandpiper and grey plover Pluvialis squatarola were the most abundant birds in the brackish lagoon. Due to the effects of wind-tides only a small area was usually available as a feeding site. Gammarus insensibilis was the alternative prey resource in the water layer, and their density varied with wind direction in the same way as brine shrimp. Curlew sandpipers and dunlins in the hypersaline lagoons and broad-billed sandpipers in the brackish lagoons often changed feeding sites, probably following the variation in prey availability. Only because of the large size and variety of lagoons are waders in the Sivash always able to find good feeding sites.

Potential changes in bacterial metabolism associated with increased water temperature and nutrient inputs in tropical humic lagoons.

PubMed

Scofield, Vinicius; Jacques, Saulo M S; Guimarães, Jean R D; Farjalla, Vinicius F

2015-01-01

Temperature and nutrient concentrations regulate aquatic bacterial metabolism. However, few studies have focused on the effect of the interaction between these factors on bacterial processes, and none have been performed in tropical aquatic ecosystems. We analyzed the main and interactive effects of changes in water temperature and N and P concentrations on bacterioplankton production (BP), bacterioplankton respiration (BR) and bacterial growth efficiency (BGE) in tropical coastal lagoons. We used a factorial design with three levels of water temperature (25, 30, and 35°C) and four levels of N and/or P additions (Control, N, P, and NP additions) in five tropical humic lagoons. When data for all lagoons were pooled together, a weak interaction was observed between the increase in water temperature and the addition of nutrients. Water temperature alone had the greatest impact on bacterial metabolism by increasing BR, decreasing BP, and decreasing BGE. An increase of 1°C lead to an increase of ~4% in BR, a decrease of ~0.9% in BP, and a decrease of ~4% in BGE. When data were analyzed separately, lagoons responded differently to nutrient additions depending on Dissolved Organic Carbon (DOC) concentration. Lagoons with lowest DOC concentrations showed the strongest responses to nutrient additions: BP increased in response to N, P, and their interaction, BR increased in response to N and the interaction between N and P, and BGE was negatively affected, mainly by the interaction between N and P additions. Lagoons with the highest DOC concentrations showed almost no significant relationship with nutrient additions. Taken together, these results show that different environmental drivers impact bacterial processes at different scales. Changes of bacterial metabolism related to the increase of water temperature are consistent between lagoons, therefore their consequences can be predicted at a regional scale, while the effect of nutrient inputs is specific to different

Potential changes in bacterial metabolism associated with increased water temperature and nutrient inputs in tropical humic lagoons

PubMed Central

Scofield, Vinicius; Jacques, Saulo M. S.; Guimarães, Jean R. D.; Farjalla, Vinicius F.

2015-01-01

Temperature and nutrient concentrations regulate aquatic bacterial metabolism. However, few studies have focused on the effect of the interaction between these factors on bacterial processes, and none have been performed in tropical aquatic ecosystems. We analyzed the main and interactive effects of changes in water temperature and N and P concentrations on bacterioplankton production (BP), bacterioplankton respiration (BR) and bacterial growth efficiency (BGE) in tropical coastal lagoons. We used a factorial design with three levels of water temperature (25, 30, and 35°C) and four levels of N and/or P additions (Control, N, P, and NP additions) in five tropical humic lagoons. When data for all lagoons were pooled together, a weak interaction was observed between the increase in water temperature and the addition of nutrients. Water temperature alone had the greatest impact on bacterial metabolism by increasing BR, decreasing BP, and decreasing BGE. An increase of 1°C lead to an increase of ~4% in BR, a decrease of ~0.9% in BP, and a decrease of ~4% in BGE. When data were analyzed separately, lagoons responded differently to nutrient additions depending on Dissolved Organic Carbon (DOC) concentration. Lagoons with lowest DOC concentrations showed the strongest responses to nutrient additions: BP increased in response to N, P, and their interaction, BR increased in response to N and the interaction between N and P, and BGE was negatively affected, mainly by the interaction between N and P additions. Lagoons with the highest DOC concentrations showed almost no significant relationship with nutrient additions. Taken together, these results show that different environmental drivers impact bacterial processes at different scales. Changes of bacterial metabolism related to the increase of water temperature are consistent between lagoons, therefore their consequences can be predicted at a regional scale, while the effect of nutrient inputs is specific to different

Diazotroph community succession during the VAHINE mesocosm experiment (New Caledonia lagoon)

NASA Astrophysics Data System (ADS)

Turk-Kubo, K. A.; Frank, I. E.; Hogan, M. E.; Desnues, A.; Bonnet, S.; Zehr, J. P.

2015-12-01

The VAHINE mesocosm experiment, conducted in the low-nutrient low-chlorophyll waters of the Noumea lagoon (coastal New Caledonia) was designed to trace the incorporation of nitrogen (N) fixed by diazotrophs into the food web, using large volume (50 m3) mesocosms. This experiment provided a unique opportunity to study the succession of different N2-fixing microorganisms (diazotrophs) and calculate in situ net growth and mortality rates in response to fertilization with dissolved inorganic phosphate (DIP) over a 23-day period, using quantitative polymerase chain reaction (qPCR) assays targeting widely distributed marine diazotroph lineages. Inside the mesocosms, the most abundant diazotroph was the heterocyst-forming Richelia associated with Rhizosolenia (Het-1) in the first half of the experiment, while unicellular cyanobacterial Group C (UCYN-C) became abundant during the second half of the experiment. Decreasing DIP concentrations following the fertilization event and increasing temperatures were significantly correlated with increasing abundances of UCYN-C. Maximum net growth rates for UCYN-C were calculated to range between 1.23 ± 0.07 and 2.16 ± 0.07 d-1 in the mesocosms, which are among the highest growth rates reported for diazotrophs. Outside the mesocosms in the New Caledonia lagoon, UCYN-C abundances remained low, despite increasing temperatures, suggesting that the microbial community response to the DIP fertilization created conditions favorable for UCYN-C growth inside the mesocosms. Diazotroph community composition analysis using PCR targeting a component of the nitrogenase gene (nifH) verified that diazotrophs targeted in qPCR assays were collectively among the major lineages in the lagoon and mesocosm samples, with the exception of Crocosphaera-like phylotypes, where sequence types not typically seen in the oligotrophic ocean grew in the mesocosms. Maximum net growth and mortality rates for nine diazotroph phylotypes throughout the 23-day

Water-quality monitoring and biological integrity assessment in the Indian River Lagoon, Florida: Status, trends, and loadings (1988--1994)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sigua, G.C.; Steward, J.S.; Tweedale, W.A.

2000-02-01

The Indian River Lagoon (IRL) system that extends from Ponce DeLeon inlet to Jupiter inlet is comprised of three interconnected estuarine lagoons: The Mosquito Lagoon (ML), the Banana River Lagoon (BRL), and the Indian River Lagoon. The declines in both the aerial coverage and species diversity of seagrass communities within the IRL system are believed to be due in part to continued degradation of water quality. Large inflows of phosphorus (P) and nitrogen (N)-laden storm-water from urban areas an agricultural land have been correlated with higher chlorophyll a production in the central, south central, and the south segments of themore » lagoon. In a system as large and complex as the lagoon, N and P limitations are potentially subject to significant spatial and temporal variability. Total Kjeidahl nitrogen (TN) was higher in the north and lower in the south. The reverse pattern was observed for total P (TP), i.e., lowest in the north and highest at the south ends of the IRL. This increased P concentration in the SIRL appears to have a significantly large effect on chlorophyll a production compared with the other segments, as indicated by stepwise regression statistics. This relationship can be expressed as follows: South IRL [chlorophyll a] = {minus}8.52 + 162.41 [orthophosphate] + 7.86 [total nitrogen] + 0.38 [turbidity]; R{sup 2} = 0.98**.« less

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.

Spatial variations in dietary organic matter sources modulate the size and condition of fish juveniles in temperate lagoon nursery sites

NASA Astrophysics Data System (ADS)

Escalas, Arthur; Ferraton, Franck; Paillon, Christelle; Vidy, Guy; Carcaillet, Frédérique; Salen-Picard, Chantal; Le Loc'h, François; Richard, Pierre; Darnaude, Audrey Michèle

2015-01-01

Effective conservation of marine fish stocks involves understanding the impact, on population dynamics, of intra-specific variation in nursery habitats use at the juvenile stage. In some regions, an important part of the catching effort is concentrated on a small number of marine species that colonize coastal lagoons during their first year of life. To determine the intra-specific variation in lagoon use by these fish and their potential demographic consequences, we studied diet spatiotemporal variations in the group 0 juveniles of a highly exploited sparid, the gilthead seabream (Sparus aurata L.), during their ∼6 months stay in a NW Mediterranean lagoon (N = 331, SL = 25-198 mm) and traced the origin of the organic matter in their food webs, at two lagoon sites with contrasted continental inputs. This showed that the origin (marine, lagoonal or continental) of the organic matter (OM) available in the water column and the sediment can vary substantially within the same lagoon, in line with local variations in the intensity of marine and continental inputs. The high trophic plasticity of S. aurata allows its juveniles to adapt to resulting differences in prey abundances at each site during their lagoon residency, thereby sustaining high growth irrespective of the area inhabited within the lagoon. However, continental POM incorporation by the juveniles through their diet (of 21-37% on average depending on the site) is proportional to its availability in the environment and could be responsible for the greater fish sizes (of 28 mm SL on average) and body weights (of 40.8 g on average) observed at the site under continental influence in the autumn, when the juveniles are ready to leave the lagoon. This suggests that continental inputs in particulate OM, when present, could significantly enhance fish growth within coastal lagoons, with important consequences on the local population dynamics of the fish species that use them as nurseries. As our results indicate that

High-resolution inversion of methane emissions in the Southeast US using SEAC4RS aircraft observations of atmospheric methane: anthropogenic and wetland sources

NASA Astrophysics Data System (ADS)

Sheng, Jian-Xiong; Jacob, Daniel J.; Turner, Alexander J.; Maasakkers, Joannes D.; Sulprizio, Melissa P.; Bloom, A. Anthony; Andrews, Arlyn E.; Wunch, Debra

2018-05-01

We use observations of boundary layer methane from the SEAC4RS aircraft campaign over the Southeast US in August-September 2013 to estimate methane emissions in that region through an inverse analysis with up to 0.25° × 0.3125° (25×25 km2) resolution and with full error characterization. The Southeast US is a major source region for methane including large contributions from oil and gas production and wetlands. Our inversion uses state-of-the-art emission inventories as prior estimates, including a gridded version of the anthropogenic EPA Greenhouse Gas Inventory and the mean of the WetCHARTs ensemble for wetlands. Inversion results are independently verified by comparison with surface (NOAA/ESRL) and column (TCCON) methane observations. Our posterior estimates for the Southeast US are 12.8 ± 0.9 Tg a-1 for anthropogenic sources (no significant change from the gridded EPA inventory) and 9.4 ± 0.8 Tg a-1 for wetlands (27 % decrease from the mean in the WetCHARTs ensemble). The largest source of error in the WetCHARTs wetlands ensemble is the land cover map specification of wetland areal extent. Our results support the accuracy of the EPA anthropogenic inventory on a regional scale but there are significant local discrepancies for oil and gas production fields, suggesting that emission factors are more variable than assumed in the EPA inventory.

Poster 17: Methane storms as a driver of Titan's dune orientation.

NASA Astrophysics Data System (ADS)

Charnay, Benjamin; Barth, Erika; Rafkin, Scot; Narteau, Clement; Lebonnois, Sebastien; Rodriguez, Sebastien; Courech Du Pont, Sylvain; Lucas, Antoine

2016-06-01

Titan's equatorial regions are covered by eastward oriented linear dunes [1,2]. This direction is opposite to mean surface winds simulated by Global Climate Models (GCMs) at these latitudes, oriented westward as trade winds on Earth. We propose that Titan's dune orientation is actually determined by equinoctial tropical methane storms producing a coupling with superrotation and dune formation [3]. Using meso-scale simulations of convective methane clouds [4] with a GCM wind profile featuring the superrotation [5,6], we show that Titan's storms should produce fast eastward gust fronts above the surface. Such gusts dominate the aeolian transport. Using GCM wind calculations and analogies with terrestrial dune fields [7], we show that Titan's dune propagation occurs eastward under these conditions. Finally, this scenario combining global circulation winds and methane storms can explain other major features of Titan's dunes as the divergence from the equator or the dune size and spacing. It also implies an equatorial origin of Titan's dune sand and a possible occurence of dust storms.

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…

Effect of climate change and mollusc invasion on eutrophication and algae blooms in the lagoon ecosystems of the Baltic Sea

NASA Astrophysics Data System (ADS)

Aleksandrov, Sergei; Gorbunova, Julia; Rudinskaya, Lilia

2015-04-01

Coastal lagoons are most vulnerable to impacts of natural environmental and anthropogenic factors. The Curonian Lagoon and Vistula Lagoon are the largest coastal lagoons of the Baltic Sea, relating to the most highly productive water bodies of Europe. The Curonian Lagoon is choke mostly freshwater lagoon, while the Vistula Lagoon is restricted brackish water lagoon. In the last decades the nutrients loading changes, warming trend and biological invasions are observed. The researches (chlorophyll, primary production, nutrients, phytoplankton, benthos, etc) were carried out monthly since 1991 to 2014. The database includes 1600 stations in the Curonian Lagoon, 1650 stations in the Vistula Lagoon. Eutrophication and algae blooms are most important problems. Multiple reductions of nutrients loading from the watershed area in 1990s did not result in considerable improvement of the ecological situation in the lagoons. The Curonian Lagoon may be characterized as hypertrophic water body with "poor" water quality. Climate change in 1990s-2000s combined with other factors (freshwater, slow-flow exchange, high nutrients concentrations) creates conditions for Cyanobacteria "hyperblooms". Hyperbloom of Cyanophyta (average for the growing season Chl > 100 μg/l) were observed during 4 years in 1990s and 7 years in 2000s. The summer water temperature is the key environmental factor determining the seasonal and long-term variability of the primary production and algae blooms. Mean annual primary production in 2010-2014 (600 gC·m-2·year-1) is considerable higher, than in the middle of 1970s (300 gC·m-2·year-1). The local climate warming in the Baltic region caused ongoing eutrophication and harmful algae blooms in the Curonian Lagoon despite of significant reduction of nutrients loading in 1990s-2000s. Harmful algal blooms in July-October (chlorophyll to 700-3400 μg/l) result in deterioration of the water chemical parameters, death of fish in the coastal zone and pollution

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

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.

Methane for Power Generation in Muaro Jambi: A Green Prosperity Model Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moriarty, K.; Elchinger, M.; Hill, G.

2014-07-01

NREL conducted eight model projects for Millennium Challenge Corporation's (MCC) Compact with Indonesia. Green Prosperity, the largest project of the Compact, seeks to address critical constraints to economic growth while supporting the Government of Indonesia's commitment to a more sustainable, less carbon-intensive future. This study evaluates electricity generation from the organic content of wastewater at a palm oil mill in Muaro Jambi, Sumatra. Palm mills use vast amounts of water in the production process resulting in problematic waste water called palm oil mill effluent (POME). The POME releases methane to the atmosphere in open ponds which could be covered tomore » capture the methane to produce renewable electricity for rural villages. The study uses average Indonesia data to determine the economic viability of methane capture at a palm oil mill and also evaluates technology as well as social and environmental impacts of the project.« less

The future of methane

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 ofmore » 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.« less

Martian methane plume models for defining Mars rover methane source search strategies

NASA Astrophysics Data System (ADS)

Nicol, Christopher; Ellery, Alex; Lynch, Brian; Cloutis, Ed

2018-07-01

The detection of atmospheric methane on Mars implies an active methane source. This introduces the possibility of a biotic source with the implied need to determine whether the methane is indeed biotic in nature or geologically generated. There is a clear need for robotic algorithms which are capable of manoeuvring a rover through a methane plume on Mars to locate its source. We explore aspects of Mars methane plume modelling to reveal complex dynamics characterized by advection and diffusion. A statistical analysis of the plume model has been performed and compared to analyses of terrestrial plume models. Finally, we consider a robotic search strategy to find a methane plume source. We find that gradient-based techniques are ineffective, but that more sophisticated model-based search strategies are unlikely to be available in near-term rover missions.

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

Assessing Pathogen Levels in Dairy Lagoon Wastewater and Potential Evaporation Losses

NASA Astrophysics Data System (ADS)

Pandey, P.; Biswas, S.; Souza, A.; Silva-del-Rio, N.; Vaddella, V. K.; Castillo, A. R.

2014-12-01

The ongoing drought in California necessitates the conservation of existing water resources while protecting the water quality. There is a critical need to improve the understanding of evaporation losses from dairy lagoons in California, and their corresponding changes in pathogen levels in the lagoon wastewater. We have carried out preliminary studies involving extensive dairy lagoon water sampling, and batch-scale experiments. The dairy wastewater was collected from both primary and secondary lagoons in three counties of California (Merced, Tulare, and Glenn Counties) for enumerating the levels of E. coli O157:H7, Salmonella spp., and Listeria monocytogenes. Subsequently, we conducted batch-scale experiments at mesophilic (31 and 37 ⁰C) and thermophilic temperatures (43 and 49 ⁰C) to understand the E. coli O157:H7 inactivation process and potential evaporative water losses. In addition, we compared the evaporation losses under the environment of biological activity and the environment of restricted biological activity (extreme environment with low pH). For E. coli O157:H7 enumeration, we used MacConkey agar, while for Salmonella spp., XLD agar was used. Listeria monocytogenes levels were measured using PALCAM agar (with selective supplement). In flushed dairy wastewater (fresh) samples, the average of E. coli O157:H7 levels were 2 × 104 CFU/mL. The average Listeria monocytogenes levels in flushed manure were 9 × 101. The levels of Salmonella spp. were non-detectable. In mesophilic condition (37 ⁰C) after 5 days of incubation, 8% of total water loss was observed, while at thermophilic temperature (49 ⁰C), 70% of total water loss was observed. After 5 days of incubation at 37 ⁰C, E. coli O157:H7 levels in flushed dairy manure were increased from 2.8 × 103 to 5.2 × 104 CFU/mL, while at 49 ⁰C, E. coli O157:H7 levels were reduced from 2.8 × 103 to 5 × 101 CFU/mL after 4 days of incubation. We anticipate that the results of this study would be useful

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

USGS Publications Warehouse

Malinverno, A.; Pohlman, J.W.

2011-01-01

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

The Effects of Surface Properties and Albedo on Methane Retrievals with the Airborne Visible/Infrared Imaging Spectrometer Next Generation (AVIRIS-NG)

NASA Astrophysics Data System (ADS)

Ayasse, A.; Thorpe, A. K.; Roberts, D. A.

2017-12-01

Atmospheric methane has increased by a factor of 2.5 since the beginning of the industrial era in response to anthropogenic emissions (Ciais et al., 2013). Although it is less abundant than carbon dioxide it is 86 time more potent on a 20 year time scale (Myhre et al., 2013) and is therefore responsible for about 20% of the total global warming induced by anthropogenic greenhouse gasses (Kirschke et al., 2013). Given the importance of methane to global climate change, monitoring and measuring methane emissions using techniques such as remote sensing is of increasing interest. Recently the Airborne Visible-Infrared Imaging Spectrometer - Next Generation (AVIRIS-NG) has proven to be a valuable instrument for quantitative mapping of methane plumes (Frankenberg et al., 2016; Thorpe et al., 2016; Thompson et al., 2015). In this study, we applied the Iterative Maximum a Posterior Differential Optical Spectroscopy (IMAP-DOAS) methane retrieval algorithm to a synthetic image with variable methane concentrations, albedo, and land cover. This allowed for characterizing retrieval performance, including potential sensitivity to variable land cover, low albedo surfaces, and surfaces known to cause spurious signals. We conclude that albedo had little influence on the IMAP-DOAS results except at very low radiance levels. Water (without sun glint) was found to be the most challenging surface for methane retrievals while hydrocarbons and some green vegetation also caused error. Understanding the effect of surface properties on methane retrievals is important given the increased use of AVIRIS-NG to map gas plumes over diverse locations and methane sources. This analysis could be expanded to include additional gas species like carbon dioxide and to further investigate gas sensitivity of proposed instruments for dedicated gas mapping from airborne and spaceborne platforms.

Dynamics of pollution-indicator and heterotrophic bacteria in sewage treatment lagoons.

PubMed

Legendre, P; Baleux, B; Troussellier, M

1984-09-01

The spatio-temporal dynamics of pollution-indicator bacteria and aerobic heterotrophic bacteria were studied in the sewage treatment lagoons of an urban wastewater center after 26 months of biweekly sampling at eight stations in these lagoons. Robust statistical methods of time-series analysis were used to study successional steps (through chronological clustering) and rhythmic behavior through time (through contingency periodogram). The aerobic heterotrophic bacterial community showed two types of temporal evolution: in the first four stations, it seems mainly controlled by the nutrient support capacity of the sewage input, whereas in the remaining part of the lagoon, it seems likely that the pollution-indicator bacteria are gradually replaced by other bacterial types that are better adapted to this environment. On the other hand, the pollution-indicator bacteria showed an annual cycle which increased in amplitude at distances further from the wastewater source. The main events in this cycle were produced simultaneously at all stations, indicating control of these bacterial populations by climatic factors, which act through physical and chemical factors, and also through other biological components of this ecosystem (phytoplankton and zooplankton). Finally, we use results from this study to suggest a modified design for a future study program.

Methane distributions and transports in the nocturnal boundary layer at a rural station

NASA Astrophysics Data System (ADS)

Schäfer, Klaus; Zeeman, Matthias; Brosy, Caroline; Münkel, Christoph; Fersch, Benjamin; Mauder, Matthias; Emeis, Stefan

2016-10-01

To investigate the methane distributions and transports, the role of related atmospheric processes by determination of vertical profiles of wind, turbulence, temperature and humidity as well as nocturnal boundary layer (NBL) height and the quantification of methane emissions at local and plot scale the so-called ScaleX-campaign was performed in a pre-alpine observatory in Southern Germany from 01 June until 31 July 2015. The following measurements from the ground up to the free troposphere were performed: layering of the atmosphere by a ceilometer (Vaisala CL51); temperature, wind, turbulence profiles from 50 m up to 500 m by a Radio-Acoustic Sounding System (RASS, Metek GmbH); temperature, humidity profiles in situ by a hexacopter; methane farm emissions by two open-path laser spectrometers (Boreal GasFinder2); methane concentrations in situ (Los Gatos DLT-100) with tubes in 0.3 m agl and 5 sampling heads; and methane soil emissions by a big chamber (10 m length, 2.60 m width, up to 0.61 m height) with a plastic cover. The methane concentrations near the surface show a daily variation with a maximum and a frequent double-peak structure during night-time. Analysis of the variation of the nocturnal methane concentration together with the hexacopter and RASS data indicates that the first peak in the nocturnal methane concentration is probably due to local cooling and stabilization which keeps the methane emissions from the soil near the ground. The second peak seems to be due to advection of methane-enriched air which had formed in the environment of the nearby farm yards. These dairy farm emissions were determined by up-wind and down-wind open-path concentration measurements, turbulence data from an EC station nearby and Backward Lagrangian Simulation (WindTrax software). The methane fluxes at plot scale (big chamber) are characterized by emissions at water saturated grassland patches, by an exponential decrease of these emissions during grassland drying, and by an

Methane from shallow seep areas of the NW Svalbard Arctic margin does not reach the sea surface

NASA Astrophysics Data System (ADS)

Silyakova, Anna; Greinert, Jens; Jansson, Pär; Ferré, Bénédicte

2015-04-01

Methane, an important greenhouse gas, leaks from large areas of the Arctic Ocean floor. One overall question is how much methane passes from the seabed through the water column, potentially reaching the atmosphere. Transport of methane from the ocean floor into and through the water column depends on many factors such as distribution of gas seeps, microbial methane oxidation, and ambient oceanographic conditions, which may trigger a change in seep activity. From June-July 2014 we investigated dissolved methane in the water column emanating from the "Prins Karls Forland seeps" area offshore the NW Svalbard Arctic margin. Measurements of the spatial variability of dissolved methane in the water column included 65 CTD stations located in a grid covering an area of 30 by 15 km. We repeated an oceanographic transect twice in a week for time lapse studies, thus documenting significant temporal variability in dissolved methane above one shallow seep site (~100 m water depth). Analysis of both nutrient concentrations and dissolved methane in water samples from the same transect, reveal striking similarities in spatial patterns of both dissolved methane and nutrients indicating that microbial community is involved in methane cycling above the gas seepage. Our preliminary results suggest that although methane release can increase in a week's time, providing twice as much dissolved gas to the water column, no methane from a seep reaches the sea surface. Instead it spreads horizontally under the pycnocline. Yet microbial communities react rapidly to the methane supply above gas seepage areas and may also have an important role as an effective filter, hindering methane release from the ocean to the atmosphere during rapid methane ebullition. This study is funded by CAGE (Centre for Arctic Gas Hydrate, Environment and Climate), Norwegian Research Council grant no. 223259.

Amount and type of derelict gear from the declining black pearl oyster aquaculture in Ahe atoll lagoon, French Polynesia.

PubMed

Andréfouët, Serge; Thomas, Yoann; Lo, Cedrik

2014-06-15

Pearl oyster aquaculture is a major activity in French Polynesia atoll lagoons. After the economic decline that characterized the last decade, concerns recently rose about discarded installations and materials that supported aquaculture practices and by facilities abandoned after they had to close their activities. In May 2013, a first inventory of the type and amount of pearl farms derelict gear (PFDG) was achieved on 47 sites in Ahe lagoon. Surveys were conducted within and outside the boundaries of aquaculture concessions. Twenty types of PFDG littered the lagoon floor and the water column. The most impacted areas were near abandoned grafting houses with up to nine types of PFDG. Forty-five percent of the sites were impacted, including outside concessions. While management authorities are fully aware of the problem, this first assessment is a wake-up call to stimulate the cleaning of lagoons, enhance awareness among farmers, and identify potential ecological consequences on lagoon ecosystems. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Hatching rhythms and dispersion of decapod crustacean larvae in a brackish coastal lagoon in Argentina

NASA Astrophysics Data System (ADS)

Anger, K.; Spivak, E.; Bas, C.; Ismael, D.; Luppi, T.

1994-12-01

Mar Chiquita, a brackish coastal lagoon in central Argentina, is inhabited by dense populations of two intertidal grapsid crab species, Cyrtograpsus angulatus and Chasmagnathus granulata. During a preliminary one-year study and a subsequent intensive sampling programme (November December 1992), the physical properties and the occurrence of decapod crustacean larvae in the surface water of the lagoon were investigated. The lagoon is characterized by highly variable physical conditions, with oligohaline waters frequently predominating over extended periods. The adjacent coastal waters show a complex pattern of semidiurnal tides that often do not influence the lagoon, due to the existence of a sandbar across its entrance. Besides frequently occurring larvae (exclusively freshly hatched zoeae and a few megalopae) of the two dominating crab species, those of three other brachyurans ( Plathyxanthus crenulatus, Uca uruguayensis, Pinnixa patagonica) and of one anomuran (the porcellanid Pachycheles haigae) were also found occasionally. Caridean shrimp ( Palaemonetes argentinus) larvae occurred in a moderate number of samples, with a maximum density of 800·m-3. The highest larval abundance was recorded in C. angulatus, with almost 8000°m-3. Significantly more C. angulatus and C. granulata zoeae occurred at night than during daylight conditions, and more larvae (statistically significant only in the former species) during ebb (outflowing) than during flood (inflowing) tides. In consequence, most crab zoeae were observed during nocturnal ebb, the least with diurnal flood tides. Our data suggest that crab larvae do not develop in the lagoon, where the adult populations live, but exhibit an export strategy, probably based upon exogenously coordinated egg hatching rhythms. Zoeal development must take place in coastal marine waters, from where the megalopa eventually returns for settlement and metamorphosis in the lagoon. Significantly higher larval frequency of C. granulata in

The ecological status of Karavasta Lagoon (Albania): Closing the stable door before the horse has bolted?

PubMed

Munari, Cristina; Tessari, Umberto; Rossi, Remigio; Mistri, Michele

2010-02-01

Karavasta is the widest and most important lagoon in Albania. This study aimed to assess the ecological quality status of the lagoon, acquire knowledge of a natural environment which might be exploited for aquaculture, and give management hints on the basis of anthropogenic impact and ecological conditions. A sampling campaign was carried out in 2008: at six stations, benthic fauna, water, and sediment parameters were considered. Statistical analyses were carried out through multivariate procedures (PCA, classification-clustering, SIMPER, RDA, DISTLM, PERMANOVA). Ecological quality was assessed through the AZTI Marine Biotic Index (AMBI), the multivariate AMBI (M-AMBI) and the Benthic Index based on Taxonomic Sufficiency (BITS). Sediment characteristics (percent organic matter, %OM; redox potential discontinuity layer depth, RPDL; particle size composition) and salinity represented contributory influences on lagoon communities. It was possible to distinguish and characterise a confined area, and benthic communities, from a marine-influenced area and its biota. The number of species was quite low when compared with other open Adriatic lagoons. The M-AMBI and BITS classifications gave quite similar results, which seemed consistent with the ecological conditions of the lagoon, that is a distinction in the ecological quality between the seaward and landward stations, with higher ecological quality (EcoQ) at the seaward stations. Given the pressures and the ecological condition of Karavasta, an intensification of aquaculture activities must be considered with caution, since the lagoon seems at significant risk of serious hypereutrophication. This situation is made worse by the limited water exchange with the marine environment due to the irregular dredging of the communication channels. 2009 Elsevier Ltd. All rights reserved.

Does coastal lagoon habitat quality affect fish growth rate and their recruitment? Insights from fishing and acoustic surveys

NASA Astrophysics Data System (ADS)

Brehmer, P.; Laugier, T.; Kantoussan, J.; Galgani, F.; Mouillot, D.

2013-07-01

Ensuring the sustainability of fish resources necessitates understanding their interaction with coastal habitats, which is becoming ever more challenging in the context of ever increasing anthropogenic pressures. The ability of coastal lagoons, exposed to major sources of disturbance, to provide resources and suitable habitats for growth and survival of juvenile fish is especially important. We analysed three lagoons with different ecological statuses and habitat quality on the basis of their eutrophication and ecotoxicity (Trix test) levels. Fish abundances were sampled using fishing and horizontal beaming acoustic surveys with the same protocols in the same year. The relative abundance of Anguilla anguilla, Dicentrarchus labrax or the Mugilidae group was not an indicator of habitat quality, whereas Atherina boyeri and Sparus aurata appeared to be more sensitive to habitat quality. Fish abundance was higher in the two lagoons with high eutrophication and ecotoxicity levels than in the less impacted lagoon, while fish sizes were significantly higher in the two most severely impacted lagoons. This leads us to suggest low habitat quality may increase fish growth rate (by the mean of a cascading effect), but may reduce lagoon juvenile abundance by increasing larval mortality. Such a hypothesis needs to be further validated using greater investigations which take into account more influences on fish growth and recruitment in such variable environments under complex multi-stressor conditions.

Effects of rainfalls variability and physical-chemical parameters on enteroviruses in sewage and lagoon in Yopougon, Côte d'Ivoire

NASA Astrophysics Data System (ADS)

Momou, Kouassi Julien; Akoua-Koffi, Chantal; Traoré, Karim Sory; Akré, Djako Sosthène; Dosso, Mireille

2017-07-01

The aim of this study was to assess the variability of the content of nutrients, oxidizable organic and particulate matters in raw sewage and the lagoon on the effect of rainfall. Then evaluate the impact of these changes in the concentration of enteroviruses (EVs) in waters. The sewage samples were collected at nine sampling points along the channel, which flows, into a tropical lagoon in Yopougon. Physical-chemical parameters (5-day Biochemical Oxygen Demand, Chemical Oxygen Demand, Suspended Particulate Matter, Total Phosphorus, Orthophosphate, Total Kjeldahl Nitrogen and Nitrate) as well as the concentration of EV in these waters were determined. The average numbers of EV isolated from the outlet of the channel were 9.06 × 104 PFU 100 ml-1. Consequently, EV was present in 55.55 and 33.33 % of the samples in the 2 brackish lagoon collection sites. The effect of rainfall on viral load at the both sewage and brackish lagoon environments is significant correlate (two-way ANOVA, P < 0.05). Furthermore, in lagoon environment, nutrients (Orthophosphate, Total Phosphorus), 5-day Biochemical Oxygen Demand, Chemical Oxygen Demand and Suspended Particulate Matter were significant correlated with EVs loads ( P < 0.05 by Pearson test). The overall results highlight the problem of sewage discharge into the lagoon and correlation between viral loads and water quality parameters in sewage and lagoon.

Evidence for Methane Segregation at the Surface of Pluto

NASA Technical Reports Server (NTRS)

Doute, S.; Schmitt, B.; Quirico, E.; Owen, T. C.; Cruikshank, Dale P.; deBergh, C.; Geballe, T. R.; Roush, T. L.

1999-01-01

In May 1995, a set of spectrophotometric curves of the system Pluto-Charon was recorded with the UKIRT telescope equipped with the spectrometer CGS4. As for the previous observations, the spectra cover a part of the near infrared range, between 1.4 and 2.55 micrometers, but with a higher resolution of approximately 700. In both the 1992 and 1995 data, the existence of solid methane is confirmed by numerous absorption bands, and the carbon monoxide and the nitrogen ices are identified by their respective signatures at 2.35 and 2.15 um. The solid nitrogen seems to be the principal icy component and forms a matrix in which the CH4 and CO molecules are diluted. However a spectroscopic analysis of the 1995 observations indicates that pure methane may coexist with its diluted phase in N2. In order to derive the horizontal and vertical distribution of these different species and to obtain some quantitative information about their characteristics, we have modeled the spectrum of May 15 that corresponds to the maximum of Pluto's visible light curve. This was achieved by means of a radiative transfer algorithm dealing with compact and stratified media. Among the various representations we have tested to describe the surface of Pluto, only a geographical mixture of three distinct units explains all the significant structures of the analyzed spectrum. The first unit is a thin granular layer of pure CH4 covering a compact polycrystalline substratum of N2-CH4-CO, which are in a molecular mixture (concentrations of and CO of the order of 0.45%, 0.1-0.2% respectively). It covers about 70% of the observed area and corresponds to volatile deposits that are sublimating under solar illumination. The second unit is either (a) a single thick layer of pure granular methane or (b) a unit similar to the first unit but with the two components inverted (i.e. with CH4 forming a substratum and the N2-CH4-CO mixture a superficial layer of fine grains). Covering 20% of the surface, it represents

Structure and diversity of fishes in a freshwater and coastal subtropical lagoon.

PubMed

Ferreira, N C; Guereschi, R M; Machado, C; Lopes, C A; Nuñer, A P O

2017-04-01

This study examined the fish communities of Peri Lagoon in southern Brazil to aid in the development of an effective management plan because the area is under threat from human activities. Sampling of fish fauna, ichthyoplankton and limnological data were compared between sites, differing by habitat type and characteristics such as depth, substratum composition and vegetation type. Results were significantly related to site, with the highest diversity and abundance recorded at shallow vegetated sites. A total of 14 fish species were recorded throughout the lagoon, with the most abundant being Hyphessobrycon luetkenii. Of the 14 species, half were sampled at their larval stage, suggesting a healthy and protected system. Significantly more larvae and eggs were collected during colder months (autumn to winter) and at sites closer to stream flow, possibly owing to increased food sources and habitat protection. This study highlights the importance of Peri Lagoon as a nursery ground for a wide range of fish species, providing essential information for incorporation into the future protection of fish stocks throughout Brazil. © 2016 The Fisheries Society of the British Isles.

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.

Diuron tolerance and potential degradation by pelagic microbiomes in the Great Barrier Reef lagoon

PubMed Central

Pantos, Olga; Morgan, Thomas C.; Rich, Virginia; Tonin, Hemerson; Bourne, David G.; Mercurio, Philip; Negri, Andrew P.; Tyson, Gene W.

2016-01-01

Diuron is a herbicide commonly used in agricultural areas where excess application causes it to leach into rivers, reach sensitive marine environments like the Great Barrier Reef (GBR) lagoon and pose risks to marine life. To investigate the impact of diuron on whole prokaryotic communities that underpin the marine food web and are integral to coral reef health, GBR lagoon water was incubated with diuron at environmentally-relevant concentration (8 µg/L), and sequenced at specific time points over the following year. 16S rRNA gene amplicon profiling revealed no significant short- or long-term effect of diuron on microbiome structure. The relative abundance of prokaryotic phototrophs was not significantly altered by diuron, which suggests that they were largely tolerant at this concentration. Assembly of a metagenome derived from waters sampled at a similar location in the GBR lagoon did not reveal the presence of mutations in the cyanobacterial photosystem that could explain diuron tolerance. However, resident phages displayed several variants of this gene and could potentially play a role in tolerance acquisition. Slow biodegradation of diuron was reported in the incubation flasks, but no correlation with the relative abundance of heterotrophs was evident. Analysis of metagenomic reads supports the hypothesis that previously uncharacterized hydrolases carried by low-abundance species may mediate herbicide degradation in the GBR lagoon. Overall, this study offers evidence that pelagic phototrophs of the GBR lagoon may be more tolerant of diuron than other tropical organisms, and that heterotrophs in the microbial seed bank may have the potential to degrade diuron and alleviate local anthropogenic stresses to inshore GBR ecosystems. PMID:26989611

Transport of steroid hormones, phytoestrogens, and estrogenic activity across a swine lagoon/sprayfield system.

PubMed

Yost, Erin E; Meyer, Michael T; Dietze, Julie E; Williams, C Michael; Worley-Davis, Lynn; Lee, Boknam; Kullman, Seth W

2014-10-07

The inflow, transformation, and attenuation of natural steroid hormones and phytoestrogens and estrogenic activity were assessed across the lagoon/sprayfield system of a prototypical commercial swine sow operation. Free and conjugated steroid hormones (estrogens, androgens, and progesterone) were detected in urine and feces of sows across reproductive stages, with progesterone being the most abundant steroid hormone. Excreta also contained phytoestrogens indicative of a soy-based diet, particularly, daidzein, genistein, and equol. During storage in barn pits and the anaerobic lagoon, conjugated hormones dissipated, and androgens and progesterone were attenuated. Estrone and equol persisted along the waste disposal route. Following application of lagoon slurry to agricultural soils, all analytes exhibited attenuation within 2 days. However, analytes including estrone, androstenedione, progesterone, and equol remained detectable in soil at 2 months postapplication. Estrogenic activity in the yeast estrogen screen and T47D-KBluc in vitro bioassays generally tracked well with analyte concentrations. Estrone was found to be the greatest contributor to estrogenic activity across all sample types. This investigation encompasses the most comprehensive suite of natural hormone and phytoestrogen analytes examined to date across a livestock lagoon/sprayfield and provides global insight into the fate of these analytes in this widely used waste management system.

Transport of Steroid Hormones, Phytoestrogens, and Estrogenic Activity across a Swine Lagoon/Sprayfield System

PubMed Central

Yost, Erin E.; Meyer, Michael T.; Dietze, Julie E.; Williams, C. Michael; Worley-Davis, Lynn; Lee, Boknam; Kullman, Seth W.

2017-01-01

The inflow, transformation, and attenuation of natural steroid hormones, phytoestrogens, and estrogenic activity was assessed across the lagoon/sprayfield system of a prototypical commercial swine sow operation. Free and conjugated steroid hormones (estrogens, androgens, and progesterone) were detected in urine and feces of sows across reproductive stages, with progesterone being the most abundant steroid hormone. Excreta also contained phytoestrogens indicative of a soy-based diet; particularly daidzein, genistein, and equol. During storage in barn pits and the anaerobic lagoon, conjugated hormones dissipated, and androgens and progesterone were attenuated. Estrone and equol persisted along the waste disposal route. Following application of lagoon slurry to agricultural soils, all analytes exhibited attenuation within 2 days. However, analytes including estrone, androstenedione, progesterone, and equol remained detectable in soil at two months post-application. Estrogenic activity in the yeast estrogen screen and T47D-KBluc in vitro bioassays generally tracked well with analyte concentrations. Estrone found to be the greatest contributor to estrogenic activity across all sample types. This investigation encompasses the most comprehensive suite of natural hormone and phytoestrogen analytes examined to date across a lagoon/sprayfield system, and provides global insight into the fate of these analytes in this widely used waste management system. PMID:25148584

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

PubMed

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

2018-05-01

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

Resolving land subsidence within the Venice Lagoon by persistent scatterer SAR interferometry

NASA Astrophysics Data System (ADS)

Teatini, P.; Tosi, L.; Strozzi, T.; Carbognin, L.; Cecconi, G.; Rosselli, R.; Libardo, S.

Land subsidence is a severe geologic hazard threatening the lowlying transitional coastal areas worldwide. Monitoring land subsidence has been significantly improved over the last decade by space borne earth observation techniques based on Synthetic Aperture Radar (SAR) interferometry. Within the INLET Project, funded by Magistrato alle Acque di Venezia - Venice Water Authority (VWA) and Consorzio Venezia Nuova (CVN), we use Interferometric Point Target Analysis (IPTA) to characterize the ground displacements within the Venice Lagoon. IPTA measures the movement of backscattering point targets (PTs) at the ground surface that persistently reflect radar signals emitted by the SAR system at different passes. For this study 80 ERS-1/2 and 44 ENVISAT SAR scenes recorded from 1992 to 2005 and from 2003 to 2007, respectively, have been processed. Highly reliable displacement measurements have been detected for thousands of PTs located on the lagoon margins, along the littorals, in major and small islands, and on single structures scattered within the lagoon. On the average, land subsidence ranges from less than 1 mm/year to 5 mm/year, with some PTs that exhibit values also larger than 10 mm/year depending on both the local geologic conditions and the anthropic activities. A network of a few tens of artificial square trihedral corner reflectors (TCRs) has been established before summer 2007 in order to monitor land subsidence in the inner lagoon areas where “natural” reflectors completely lack (e.g., on the salt marshes). The first interferometric results on the TCRs appear very promising.

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

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...

SPREADING LAGOONED SEWAGE SLUDGE ON FARMLAND: A CASE HISTORY

EPA Science Inventory

This project demonstrated that land application is feasible and practical for a metropolitan treatment plant for disposal of a large volume (265,000 cu m) of stabilized, liquid sewage sludge stored in lagoons. The project involved transportation of sludge by semi-trailer tankers ...

Organotins' fate in lagoon sewage system: dealkylation and sludge sorption/desorption.

PubMed

Ophithakorn, Thiwari; Sabah, Aboubakr; Delalonde, Michele; Bancon-Montigny, Chrystelle; Suksaroj, Thunwadee Tachapattaworakul; Wisniewski, Christelle

2016-11-01

Organotin compounds (OTs) have been widely used for their biocidal properties and as stabilizers in various industrial applications. Due to their high toxicity, organotins are subject to many studies regarding their behavior in wastewater treatment plant and aquatic environment. However, few studies are available regarding their behavior in lagoon sewage system, although such treatment is commonly used for sewage treatment in low-population areas. The present study aimed at studying the fate of organotins (monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT)) in lagoon sewage system. Short-term experiments, carried out at lab scale, consisted in sampling sludge from aerobic stabilization ponds, and then quantifying sorption and desorption of the different organotin species, as well as their respective transformation, under defined operating conditions (e.g., tributyltin spike and dilution) simulating possible change in the surrounding environment of sludge in the lagoon. Results established that a very important percentage of the OTs was localized in the solid phase of the sludge (more than 98 %), whatever the operating conditions may be; however, transformation and locations of the three OT species differed according to the different conditions of sludge dilution, TBT spiking, and test duration. After dilution of lagoon sludge, TBT desorption from sludge was observed; it was supposed that dealkylation of TBT after desorption occurred rapidly and increased dissolved MBT and DBT in liquid phase; MBT sorbed subsequently on solid phase. The nature of the diluent (i.e., tap water or saline solution) appeared to slightly influence the sludge behavior. After TBT spiking, TBT was supposed to be rapidly sorbed but also transformed in DBT and MBT that would as well sorbed on the sludge, which explained the decrease of these species in the liquid phase. Tests aimed at studying long-term effect of TBT spiking demonstrated that the sorbed species could be remobilized

Using hydrochemistry, tracers and isotopes to analyze hydrogeological dynamics and eutrophication processes in coastal lagoons

NASA Astrophysics Data System (ADS)

Menció, Anna; Mas-Pla, Josep; Quintana, Xavier D.

2016-04-01

Wetlands and coastal lagoons in Mediterranean areas have recently been the focus of an increasing interest due to the degradation of their ecological status in terms of declining biodiversity, alteration of ecological functioning and limitation of the ecosystem services they provide. Accordingly, the Horizon 2020 Programme of the European Union has set, as one of its priorities, to prevent a further degradation of these ecosystems and to recover their ecological functioning. The aim of this project is to analyze the hydrogeological dynamics in the Pletera coastal lagoons (NE, Spain) as a basis to propose guidelines for their sustainable management. Thus, monthly hydrochemical (with major ions, nutrients and tracers) and isotopic (δ18OH2O and δD) campaigns have been conducted, from November 2014 to October 2015, to determine the hydrogeological dynamics of the Pletera lagoons. In addition, in some of the sampling campaigns δ34SSO4, δ18OSO4, δ15NNO3 and δ18ONO3 have also been analyzed to determine the origin of eutrophication problems observed in these lagoons, mainly caused by nitrogen compounds. Project founded by MEC CGL-2014-57215-C4-2R and LIFE 13 NAT/ES/001001

Aghien lagoon: a sustainable resource of fresh water for the city of Abidjan (Ivory Coast)? Description of the project and preliminary results

NASA Astrophysics Data System (ADS)

Kamagaté, Bamory; Effebi, Rose K.; Goula Bi, Tié Albert; Lanciné Goné, Droh; Noufé, Djibril; Diallo, Seydou; Ehouman, Serge K.; Koffi, Thierry; Zamblé Trabi, Armand; Lazare, Kouakou; Paturel, Jean Emmanuel; Perrin, Jean-Louis; Salles, Christian; Seguis, Luc; Tournoud, Marie-George; Karoui, Hela

2016-04-01

With more than 6 million inhabitants, Abidjan district faces tremendous difficulties in water supply. The aquifer of the Continental Terminal which is actually the only drinking water source of the city shows a decline of resources and water demand is increasing due to the population growth. Moreover significant evidences of chemical and biological pollution of the groundwater are observed The Aghien lagoon, the largest freshwater pool located near Abidjan, has been identified by the State of Côte d'Ivoire as a potential resource for the production of drinking water.. The main objective of this project is to assess the quantitative and qualitative capacity of the Aghien lagoon to complement the water supply of Abidjan city in the near future. The main components of the project are: • to assess the water budget of the lagoon and its tributaries, • to characterize the spatial and temporal variability of contaminant levels and fluxes from the tributaries toward the lagoon, • to assess the sustainability of the water resources (quantity and quality) of the lagoon according to land use changes in the catchments . The project started in January 2015. The first year was devoted to the set-up of hydro-meteorological gauges within the lagoon watershed. Three major tributaries of the lagoon are considered, the Mé (4000 km2), the Djibi (78 km2) and Bete (206 km2) rivers. Since the start of the project, bi-monthly hydrochemical sampling surveys have been carried out along the tributaries and in the lagoon. The data available from the surveys concern the physico-chemical parameters, trace elements, all the forms of nitrogen and phosphorus, organic carbon, suspended solids. The Djibi and Bete watersheds are partly urbanized while the Mé basin is mainly rural. Baseflow has been identified as the major contribution to streamflow at the annual scale. The Mé flows into a channel downstream to the Aghien lagoon but during the floods, water from the Mé River can flow up the

Binding of methane to activated mineral surfaces - a methane sink on Mars?

NASA Astrophysics Data System (ADS)

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

2015-10-01

Tumbling experiments that simulate the wind erosion of quartz grains in an atmosphere of 13 C-enriched methane are reported. The eroded grains are analyzed by 13C and 29 Si solid-state NMR techniques after several months of tumbling. The analysis shows that methane has reacted with the eroded surface to form covalent Si-CH3 bonds, which stay intact for temperatures up to at least 250oC. These findings offer a model for a methane sink that might explain the fast disappearance of methane on Mars.

Widespread methane leakage from the sea floor on the northern US Atlantic margin

USGS Publications Warehouse

Skarke, Adam; Ruppel, Carolyn; Kodis, Mali'o; Brothers, Daniel S.; Lobecker, Elizabeth A.

2014-01-01

Methane emissions from the sea floor affect methane inputs into the atmosphere, ocean acidification and de-oxygenation, the distribution of chemosynthetic communities and energy resources. Global methane flux from seabed cold seeps has only been estimated for continental shelves, at 8 to 65 Tg CH4 yr−1, yet other parts of marine continental margins are also emitting methane. The US Atlantic margin has not been considered an area of widespread seepage, with only three methane seeps recognized seaward of the shelf break. However, massive upper-slope seepage related to gas hydrate degradation has been predicted for the southern part of this margin, even though this process has previously only been recognized in the Arctic. Here we use multibeam water-column backscatter data that cover 94,000 km2 of sea floor to identify about 570 gas plumes at water depths between 50 and 1,700 m between Cape Hatteras and Georges Bank on the northern US Atlantic passive margin. About 440 seeps originate at water depths that bracket the updip limit for methane hydrate stability. Contemporary upper-slope seepage there may be triggered by ongoing warming of intermediate waters, but authigenic carbonates observed imply that emissions have continued for more than 1,000 years at some seeps. Extrapolating the upper-slope seep density on this margin to the global passive margin system, we suggest that tens of thousands of seeps could be discoverable.

Hydrological heterogeneity, nutrient dynamics and water quality of a non-tidal lentic ecosystem (Lesina Lagoon, Italy)

NASA Astrophysics Data System (ADS)

Roselli, Leonilde; Fabbrocini, Adele; Manzo, Cristina; D'Adamo, Raffaele

2009-10-01

The dynamics of the Lesina coastal lagoon (Italy) in terms of nutrients, phytoplankton and chemical-physical parameters were evaluated, together with their functional relationships with freshwater inputs, in order to identify ecosystem responses to changes in driving forces in a Mediterranean non-tidal lentic environment. Lesina Lagoon is a shallow coastal environment characterised by limited exchange with coastal waters, which favours enrichment of nutrients and organic matter and benthic fluxes within the system. Lagoon-sea exchanges are influenced by human management. There is a steep salinity gradient from East to West. High nitrogen and silica values were found close to freshwater inputs, indicating wastewater discharges and agricultural runoff, especially in winter. Dissolved oxygen was well below saturation (65%) near sewage and runoff inputs in the western part of the lagoon during summer. Classification in accordance with EEA (2001) guidelines suggests the system is of "poor" or "bad" quality in terms of nitrogen concentrations in the eastern zone during the winter rainy period. In terms of phosphate concentrations, the majority of the stations fall into the "good" category, with only two stations (close to the sewage and runoff inputs) classed as "bad". In both cases, the raw nitrogen levels make the lagoon a P-limited system, especially in the eastern part. There was wide space-time variability in chlorophyll a concentrations, which ranged from 0.25 to 56 μg l -1. No relationships between chlorophyll a and nutrients were found, suggesting that autotrophic biomass may be controlled by a large number of internal and external forcing factors driving eutrophication processes. Water quality for this type of environment depends heavily on pressure from human activities but also on the management of sewage treatment plants, agricultural practices and the channels connecting the lagoon with the sea.

Characterisation of methane isotope composition over the Silesian Coal Basin, Poland.

NASA Astrophysics Data System (ADS)

Necki, Jaroslaw; Zimnoch, Miroslaw; Jasek, Alina; Chmura, Lukasz; Galkowski, Michal; Wolkowicz, Wojciech

2017-04-01

Methane emissions from Silesian Coal Basin (SCB), one of European regions associated with coal excavation industry constitute an important component of the continental anthropogenic flux of this gas into the atmosphere. It is estimated by different methodology that SCB is responsible for between 450 - 1350 Gg CH4 of atmospheric methane releases annually, making it one of the most significant sources of this gas in Europe. In this region, active or restructuring coal mining methane emissions may lead to elevated concentrations of this gas in near-ground atmosphere. Observed methane mixing ratio in pbl during nighttime over the specific areas of SCB is elevated by up to 50ppm with carbon isotope source ratio -46‰ to -52‰ with occasionally lighter methane (-58) form particular coal beds. Numbers were derived from direct measurement of samples taken from ventilation shafts (concentration 1.5% to 4% of CH4, subsequently diluted to 2ppm with zero air and measured by Picarro CRDS analyzer). Measurements of CH4 mixing ratios and isotopic composition were performed along latitudinal transects (ca. 50oN), typically extending from ca. 15oE to 20oE, covering the Upper Silesia and bordering regions on the public roads in vicinity of the mine ventilation shafts. Apart from CH4 emissions associated with coal production, other sources of anthropogenic methane are also active over SCB. These include city gas networks leakages that enrich the air by up to 5ppm (in the city centers, carbon isotope ratio on average -52). Most of the numerous landfills, not yet equipped with appropriate CH4 uptake installations, also contribute to substantial anthropogenic flux of this gas to the atmosphere. Values of methane mixing ratio recorded during the in-situ measurements close to the landfill sites reached 15ppm (with carbon isotope ratio -56‰ to -60). The transects of methane concentration over Silesian area, assisted by analysis of its stable isotopic composition has been performed in

Radiochemical methodology for the determination of the mass balance of suspended particulate materials exchanged at the inlets of the Venice Lagoon

NASA Astrophysics Data System (ADS)

Degetto, S.; Cantaluppi, C.

2004-11-01

The Venice Lagoon is connected to the Adriatic Sea by three inlets, with an average daily water inflow of 345∗10 6 m 3. Due to the diversion of the major rivers out of the lagoon (done in the past centuries), the sediment supply from the drainage basin is now very low when compared to the amount of sediment exchanged at the inlets (<1%). The limited sediment supply and the combined action of natural and anthropic pressures (e.g. waves, ships, fishing activities, dredging for navigation purposes) have caused in the last few decades a significant erosion of mudflats and salt-marshes. In order to investigate the history and the characteristics of the above phenomenon, with particular regard to the most recent years and the future trend, a wide radiochemical survey has been carried out in the whole lagoon, including the characterisation of the suspended particulate matter entering and leaving the lagoon in different tidal and meteorological conditions, with the aim of obtaining an indirect estimate of the sediment mass balance of the lagoon. The proposed radiochemical methodology, which is based on concentration measurements of airborne radionuclides in suspended particulate matter, appears to be an useful alternative to direct methods (e.g. bathymetric campaigns in the lagoon or mass fluxes measurements of the suspended particulate materials exchanged at the inlets). The results obtained, which show a complex sedimentary situation, highlight the erosion acting in some central and southern lagoon areas but recognise also the present accumulation phase coming into view in the northern lagoon.

Project identification for methane reduction options

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 themore » projects, and additional gains which come from the projects.« less

Dioxins in the Venice lagoon: Present situation, projects and recovering hypotheses.

PubMed

Raccanelli, S; Bonamin, V

2000-01-01

Venice is famous around the world for its uniqueness and architectural splendours, arts and the history of the "Serenissima Repubblica", as it was known in the past, but few are aware that Venice economy is strongly dependent on the industrial activities based mainly on the adjacent Porto Marghera area. For many years, the lagoon that physically separates the city from the dry land has avoided association between the concern connected with the pollution derived from these industrial activities and the public perception of Venice. Since 1995, dioxins have appeared as a lagoon contaminant, and their presence, at such a level requiring immediate "in depth" studies and interventions, has been fully realized for decades.

75 FR 53299 - Issuance of NPDES General Permits for Wastewater Lagoon Systems Located in Indian Country in...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-31

... ENVIRONMENTAL PROTECTION AGENCY [FRL-9195-3] Issuance of NPDES General Permits for Wastewater... Elimination System (NPDES) general permits for wastewater lagoon systems that are located in Indian country in... general permit for wastewater lagoon systems that are located in Indian country in the State of Colorado...

Improved water quality and reduction of odorous compounds in anaerobic lagoon columns receiving pre-treated pig wastewater

USDA-ARS?s Scientific Manuscript database

Large volumes of wastewater from confined pig production are stored in anaerobic lagoons. Control methods are needed to reduce air pollution by foul odors released from these lagoons. In a pilot-scale experiment, we evaluated the effect of pig wastewater pre-treatment on reducing the concentration o...

Assessment of hydrologic and water quality data collected in Abbotts Lagoon watershed, Point Reyes National Seashore, California, during water years 1999 and 2000

USGS Publications Warehouse

Kratzer, Charles R.; Saleh, Dina K.; Zamora, Celia

2006-01-01

Abbotts Lagoon is part of Point Reyes National Seashore, located about 40 miles northwest of San Francisco and about 20 miles south of Bodega Bay. Water-quality samples were collected quarterly during water year 1999 at a site in each of three connected lagoons that make up Abbotts Lagoon and at a site in its most significant tributary. The quarterly samples were analyzed for major ions, nutrients, and chlorophyll-a. A bed-sediment sample was collected in each lagoon during August 1999 and was analyzed for organic carbon, iron, and total phosphorus. Seven tributaries were sampled during a February 1999 storm and four during an April 1999 storm. These samples were analyzed only for nutrients. One storm sample collected in April 1999 from a tributary downstream of the I Ranch dairy was analyzed for a suite of 47 compounds indicative of wastewater. Continuous water-level recorders were installed in the most significant tributary and the two largest lagoons for portions of the study. A water budget analysis for an April 2000 storm indicated that the main tributary accounted for 85 percent of surface inflows to Abbotts Lagoon. The portion of the surface inflow from the main tributary was lower in the February 1999 storms and is a function of upstream storage and vegetative growth in the tributary basins. Another water budget analysis for a period of no surface inflow (June and July 2000) indicated that the net ground-water contribution was an outflow (seepage) from Abbotts Lagoon of about 0.3 ft3/s. Salinity increased and nutrient concentrations decreased from upstream to downstream in the chain of lagoons. The lower lagoon, nearest the ocean, had less organic carbon and total phosphorus in the bed sediment than the upper lagoons. The two tributaries originating in the I Ranch dairy had the highest concentrations of nutrients in storm runoff, and the highest loading rates and yields of ammonia and phosphorus. These tributaries account for only 10.3 percent of the area

Sources and fate of sediment organic matter in Asia's largest brackish water lagoon and nearby mangrove ecosystem

NASA Astrophysics Data System (ADS)

Mukherjee, R.; Muduli, P. R.; Barik, S.; Kumar, S.

2017-12-01

Coastal lagoons and mangrove ecosystems regularly undergo natural (tidal) and anthropogenic (riverine inputs) forcings. After effects of these forcings cause coastal environments to sustain high biological production leading to high suspended organic matter (OM) and hence fast sedimentation and accumulation of OM in sediments.The different sources of OM and its burial in tropical lacustrine and mangrove systems have been rarely studied in detail with a few reports from Indian estuaries. The present study attempts to understand the sources and fate organic matter at two Ramsar sites, viz. Chilika Lake (Asia's largest brackish water lagoon) and nearby Bhitarkanika mangroves, located in the east coast of India. We measured nitrogen and carbon content (% N and % C) and isotopic composition (δ13Corg and δ15N) of OM at different depths in eight and three sediment cores collected from the Chilika lagoon and Bhitarkanika mangroves, respectively. Overall, the mean δ13Corg and % C in the lagoon were ‒21.10 ± 0.79 ‰ and 0.84 ± 0.47 %, respectively; whereas the same for mangrove cores were ‒24.56 ± 0.80 ‰ and 1.04 ± 0.26 %, respectively. Similarly, average δ15N and % N in the lagoon cores were 4.15 ± 0.63 ‰ and 0.11 ± 0.05 %, respectively; for mangrove cores the values were 4.28 ± 0.50 ‰ and 0.07 ± 0.01 %, respectively. Preliminary analysis of the isotopic composition (δ13Corg and δ15N) and elemental ratios indicates that organic carbon in the sediment at Bhitarkanika mangrove was of terrigenous, marine and in situ origin, whereas cores of Chilika lagoon showed predominantly marine signature. No relationship between δ13Corg of suspended and sediment in the Chilika lagoon indicates these two organic pools to be not directly coupled. End member mixing model in the mangrove ecosystem indicate on an average 50 % terrestrial contribution to the OM pool.

Satellite-derived methane hotspot emission estimates using a fast data-driven method

NASA Astrophysics Data System (ADS)

Buchwitz, Michael; Schneising, Oliver; Reuter, Maximilian; Heymann, Jens; Krautwurst, Sven; Bovensmann, Heinrich; Burrows, John P.; Boesch, Hartmut; Parker, Robert J.; Somkuti, Peter; Detmers, Rob G.; Hasekamp, Otto P.; Aben, Ilse; Butz, André; Frankenberg, Christian; Turner, Alexander J.

2017-05-01

Methane is an important atmospheric greenhouse gas and an adequate understanding of its emission sources is needed for climate change assessments, predictions, and the development and verification of emission mitigation strategies. Satellite retrievals of near-surface-sensitive column-averaged dry-air mole fractions of atmospheric methane, i.e. XCH4, can be used to quantify methane emissions. Maps of time-averaged satellite-derived XCH4 show regionally elevated methane over several methane source regions. In order to obtain methane emissions of these source regions we use a simple and fast data-driven method to estimate annual methane emissions and corresponding 1σ uncertainties directly from maps of annually averaged satellite XCH4. From theoretical considerations we expect that our method tends to underestimate emissions. When applying our method to high-resolution atmospheric methane simulations, we typically find agreement within the uncertainty range of our method (often 100 %) but also find that our method tends to underestimate emissions by typically about 40 %. To what extent these findings are model dependent needs to be assessed. We apply our method to an ensemble of satellite XCH4 data products consisting of two products from SCIAMACHY/ENVISAT and two products from TANSO-FTS/GOSAT covering the time period 2003-2014. We obtain annual emissions of four source areas: Four Corners in the south-western USA, the southern part of Central Valley, California, Azerbaijan, and Turkmenistan. We find that our estimated emissions are in good agreement with independently derived estimates for Four Corners and Azerbaijan. For the Central Valley and Turkmenistan our estimated annual emissions are higher compared to the EDGAR v4.2 anthropogenic emission inventory. For Turkmenistan we find on average about 50 % higher emissions with our annual emission uncertainty estimates overlapping with the EDGAR emissions. For the region around Bakersfield in the Central Valley we

Methane production enhancement by an independent cathode in integrated anaerobic reactor with microbial electrolysis.

PubMed

Cai, Weiwei; Han, Tingting; Guo, Zechong; Varrone, Cristiano; Wang, Aijie; Liu, Wenzong

2016-05-01

Anaerobic digestion (AD) represents a potential way to achieve energy recovery from waste organics. In this study, a novel bioelectrochemically-assisted anaerobic reactor is assembled by two AD systems separated by anion exchange membrane, with the cathode placing in the inside cylinder (cathodic AD) and the anode on the outside cylinder (anodic AD). In cathodic AD, average methane production rate goes up to 0.070 mL CH4/mL reactor/day, which is 2.59 times higher than AD control reactor (0.027 m(3) CH4/m(3)/d). And COD removal is increased ∼15% over AD control. When changing to sludge fermentation liquid, methane production rate has been further increased to 0.247 mL CH4/mL reactor/day (increased by 51.53% comparing with AD control). Energy recovery efficiency presents profitable gains, and economic revenue from increased methane totally self-cover the cost of input electricity. The study indicates that cathodic AD could cost-effectively enhance methane production rate and degradation of glucose and fermentative liquid. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dynamics of pollution-indicator and heterotrophic bacteria in sewage treatment lagoons.

PubMed Central

Legendre, P; Baleux, B; Troussellier, M

1984-01-01

The spatio-temporal dynamics of pollution-indicator bacteria and aerobic heterotrophic bacteria were studied in the sewage treatment lagoons of an urban wastewater center after 26 months of biweekly sampling at eight stations in these lagoons. Robust statistical methods of time-series analysis were used to study successional steps (through chronological clustering) and rhythmic behavior through time (through contingency periodogram). The aerobic heterotrophic bacterial community showed two types of temporal evolution: in the first four stations, it seems mainly controlled by the nutrient support capacity of the sewage input, whereas in the remaining part of the lagoon, it seems likely that the pollution-indicator bacteria are gradually replaced by other bacterial types that are better adapted to this environment. On the other hand, the pollution-indicator bacteria showed an annual cycle which increased in amplitude at distances further from the wastewater source. The main events in this cycle were produced simultaneously at all stations, indicating control of these bacterial populations by climatic factors, which act through physical and chemical factors, and also through other biological components of this ecosystem (phytoplankton and zooplankton). Finally, we use results from this study to suggest a modified design for a future study program. Images PMID:6497372

Future methane emissions from animals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastasi, C.; Simpson, V.J.

1993-04-20

The authors project future methane emissions from animals to the year 2025. They review the present estimated sources of methane from enteric fermentation in animals. Ruminant animals produce the highest concentrations of methane. Methane is a byproduct of anaerobic breakdown of carbohydrates by microbes in the digestive tract of herbatious animals. In general the methane production depends on the variety of animal, the quality of the feed, and the feeding level. Since cattle, sheep, and buffalo account for roughly 91% of all animal methane emission, they only study these animals in detail. Results suggest a rise in methane production ofmore » roughly 1% per year averaged through 2025. Increasing levels are found to originate from developed countries even though the feedstock levels are lower.« less

Global Methane Initiative

EPA Pesticide Factsheets

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

Morphometric or morpho-anatomal and genetic investigations highlight allopatric speciation in Western Mediterranean lagoons within the Atherina lagunae species (Teleostei, Atherinidae)

NASA Astrophysics Data System (ADS)

Trabelsi, M.; Maamouri, F.; Quignard, J.-P.; Boussaïd, M.; Faure, E.

2004-12-01

Current distribution of Atherina lagunae poses an interesting biogeographical problem as this species inhabits widely separate circum-Mediterranean lagoons. Statistical analyses of 87 biometric parameters and genetic variation in a portion of the cytochrome b gene were examined in four populations of A. lagunae from Tunisian and French lagoons. The results suggested a subdivision into two distinct Atherinid groups: one included the French lagoonal sand smelts and the second included the Tunisian ones. Tunisian lagoonal sand smelts were distinguished from the French ones by the lower number of lateral line scales, vertebrae, pectorals and first dorsal fin rays and the higher number of lower and total gillrakers. In addition, A. lagunae from Tunisian lagoons are characterised by short preorbital length, developed operculum, broad interorbital space, larger head, robust body and a relatively small first dorsal fin which is positioned backwards. In addition, intraspecific sequence variation in a portion of the cytochrome b gene was examined in 87 individuals from Tunisia and France. The high correlation between the results of the molecular phylogenetic tree and biometric statistical data analysis suggested that two different sibling species or at least sub-species or semi-species have colonised the lagoons. In addition, our analyses suggested that the evolution of A. lagunae probably occurred in two steps including marine sympatric speciation within the large Atherina boyeri complex and a post-Pleistocene colonisation of the lagoons.

State-of-the-art in coalbed methane drilling fluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baltoiu, L.V.; Warren, B.K.; Natras, T.A.

2008-09-15

The production of methane from wet coalbeds is often associated with the production of significant amounts of water. While producing water is necessary to desorb the methane from the coal, the damage from the drilling fluids used is difficult to assess, because the gas production follows weeks to months after the well is drilled. Commonly asked questions include the following: What are the important parameters for drilling an organic reservoir rock that is both the source and the trap for the methane? Has the drilling fluid affected the gas production? Are the cleats plugged? Does the 'filtercake' have an impactmore » on the flow of water and gas? Are stimulation techniques compatible with the drilling fluids used? This paper describes the development of a unique drilling fluid to drill coalbed methane wells with a special emphasis on horizontal applications. The fluid design incorporates products to match the delicate surface chemistry on the coal, a matting system to provide both borehole stability and minimize fluid losses to the cleats, and a breaker method of removing the matting system once drilling is completed. This paper also discusses how coal geology impacts drilling planning, drilling practices, the choice of drilling fluid, and completion/stimulation techniques for Upper Cretaceous Mannville-type coals drilled within the Western Canadian Sedimentary Basin. A focus on horizontal coalbed methane (CBM) wells is presented. Field results from three horizontal wells are discussed, two of which were drilled with the new drilling fluid system. The wells demonstrated exceptional stability in coal for lengths to 1000 m, controlled drilling rates and ease of running slotted liners. Methods for, and results of, placing the breaker in the horizontal wells are covered in depth.« less

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

USGS Publications Warehouse

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

2016-01-01

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

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

NASA Astrophysics Data System (ADS)

Weinstein, Alexander; Navarrete, Luis; Ruppel, Carolyn; Weber, Thomas C.; Leonte, Mihai; Kellermann, Matthias Y.; Arrington, Eleanor C.; Valentine, David L.; Scranton, Mary I.; Kessler, John D.

2016-10-01

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

Investigation of residence time and groundwater flux in Venice Lagoon: comparing radium isotope and hydrodynamic models.

PubMed

Rapaglia, John; Ferrarin, Christian; Zaggia, Luca; Moore, Willard S; Umgiesser, Georg; Garcia-Solsona, Ester; Garcia-Orellana, Jordi; Masqué, Pere

2010-07-01

The four naturally-occurring isotopes of radium were coupled with a previously evaluated hydrodynamic model to determine the apparent age of surface waters and to quantify submarine groundwater discharge (SGD) into the Venice Lagoon, Italy. Mean apparent age of water in the Venice Lagoon was calculated using the ratio of 224Ra to 228Ra determined from 30 monitoring stations and a mean pore water end member. Average apparent age was calculated to be 6.0 d using Ra ratios. This calculated age was very similar to average residence time calculated for the same period using a hydrodynamic model (5.8 d). A mass balance of Ra was accomplished by quantifying each of the sources and sinks of Ra in the lagoon, with the unknown variable being attributed to SGD. Total SGD were calculated to be 4.1 +/- 1.5, 3.8 +/- 0.7, 3.0 +/- 1.3, and 3.5 +/- 1.0 x 10(10) L d(-1) for (223,224,226, 228)Ra, respectively, which are an order of magnitude larger than total mean fluvial discharge into the Venice Lagoon (3.1 x 10(9) L d(-1)). The SGD as a source of nutrients in the Venice Lagoon is also discussed and, though significant to the nutrient budget, is likely to be less important as the dominant control on SGD is recirculated seawater rather than freshwater. 2009 Elsevier Ltd. All rights reserved.

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

PubMed

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

2014-12-28

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

Methane - fuel for the future

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGeer, P.; Durbin, E.

1982-01-01

The 20 invited papers presented at the world conference on alternative fuel entitled 'Methane - fuel for the future' form the basis of this book. Papers discuss: the availability of alternative fuels (natural gas, biomass conversion to methane, methane from coal conversion); technological adaptions for alternative fuels (e.g. natural gas fueled engines, methane and diesel engines); commercial experience with alternative fuel programs. (e.g. retailing of methane); and some national programs for alternative fuels. One paper has been abstracted separately.

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

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

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

NASA Technical Reports Server (NTRS)

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

2011-01-01

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

Characterization and evolution of the sediments of a Mediterranean coastal lagoon located next to a former mining area.

PubMed

García, Gregorio; Muñoz-Vera, Ana

2015-11-15

Coastal lagoons are ecosystems that are relatively enclosed water bodies under the influence of both the terrestrial and the marine environment, being vulnerable to human impacts. Human activities, such as mining extraction, are significant anthropogenic coastal stressors that can negatively affect ecosystems and communities. In light of the above, the objective of this research is to examine the influence of metal mining activities on the composition of sediments of a Mediterranean coastal lagoon, named Mar Menor. This paper presents a comprehensive characterization for grain size, mineralogy, geochemistry and organic matter of sediments of this coastal lagoon, investigating their variation along space and time. Sedimentation dynamics are ruling clearly the grain size predominant in each area of the Mar Menor coastal lagoon, determining the existence of entrainment, transport and sedimentation areas. For minerals, elements and organic matter, sedimentation dynamics are also determining their distribution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Benthic foraminifera as bio-indicators of trace element pollution in the heavily contaminated Santa Gilla lagoon (Cagliari, Italy).

PubMed

Frontalini, Fabrizio; Buosi, Carla; Da Pelo, Stefania; Coccioni, Rodolfo; Cherchi, Antonietta; Bucci, Carla

2009-06-01

In order to assess the response of benthic foraminifera to trace element pollution, a study of benthic foraminiferal assemblages was carried out into sediment samples collected from the Santa Gilla lagoon (Sardinia, Italy). The lagoon has been contaminated by industrial waste, mainly trace elements, as well as by agricultural and domestic effluent. The analysis of surficial sediment shows enrichment in trace elements, including Cr, Cu, Hg, Ni, Pb and Zn. Biotic and abiotic data, analyzed with multivariate techniques of statistical analysis, reveal a distinct separation of both the highly polluted and less polluted sampling sites. The innermost part of the lagoon, comprising the industrial complex at Macchiareddu, is exposed to a high load of trace elements which are probably enhanced by their accumulation in the finer sediment fraction. This area reveals lower diversity and higher percentages of abnormalities when compared to the outermost part of the lagoon.

Forest cockchafer larvae as methane production hotspots in soils and their importance for net soil methane fluxes

NASA Astrophysics Data System (ADS)

Görres, Carolyn-Monika; Kammann, Claudia; Murphy, Paul; Müller, Christoph

2016-04-01

Certain groups of soil invertebrates, namely scarab beetles and millipedes, are capable of emitting considerable amounts of methane due to methanogens inhabiting their gut system. It was already pointed out in the early 1990's, that these groups of invertebrates may represent a globally important source of methane. However, apart from termites, the importance of invertebrates for the soil methane budget is still unknown. Here, we present preliminary results of a laboratory soil incubation experiment elucidating the influence of forest cockchafer larvae (Melolontha hippocastani FABRICIUS) on soil methane cycling. In January/February 2016, two soils from two different management systems - one from a pine forest (extensive use) and one from a vegetable field (intensive use) - were incubated for 56 days either with or without beetle larvae. Net soil methane fluxes and larvae methane emissions together with their stable carbon isotope signatures were quantified at regular intervals to estimate gross methane production and gross methane oxidation in the soils. The results of this experiment will contribute to testing the hypothesis of whether methane production hotspots can significantly enhance the methane oxidation capacity of soils. Forest cockchafer larvae are only found in well-aerated sandy soils where one would usually not suspect relevant gross methane production. Thus, besides quantifying their contribution to net soil methane fluxes, they are also ideal organisms to study the effect of methane production hotspots on overall soil methane cycling. Funding support: Reintegration grant of the German Academic Exchange Service (DAAD) (#57185798).

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.

Influence of environmental variation on the bacterioplankton community and its loss to viral lysis in the Curonian Lagoon

NASA Astrophysics Data System (ADS)

Šulčius, Sigitas; Reunamo, Anna; Paškauskas, Ričardas; Leskinen, Piia

2018-05-01

Coastal lagoons are continuously exposed to strong environmental gradients that determine the distribution and trophic interactions of microbial communities. Therefore, in this study we assessed whether and how environmental changes influence the bacterial community and its vulnerability to viral infection and lysis along the major environmental gradient in the Curonian Lagoon. We found significant differences in bacterial community profiles, their richness and evenness between the riverine, freshwater southern part and the Baltic Sea water intrusion-influenced northern part of the lagoon, suggesting strong environmental control of the structure of bacterial communities. Viruses were found to be play an important role in bacterial mortality in the Curonian Lagoon, being responsible for the removal of 20-50% of the bacterial standing stock. We observed differences in virioplankton decay rates and virus burst sizes between the northern and southern parts of the lagoon. However, no relationships were found between viral activity and bacterial communities within the lagoon ecosystem. The frequency of infected cells and virus-mediated bacterial mortality (VMBM) remained constant among the sampling sites irrespective of differences in bacteria community assemblages and environmental conditions. The results indicate that factors determining changes in bacterial diversity are different from the factors limiting their vulnerability to viral infection and lysis. This study also suggests that under changing environmental conditions, virus-bacteria interactions are more stable than the interacting viral and bacterial communities themselves. These findings are important for understanding the functioning of the coastal ecosystems under the rapidly changing local (spatial and temporal) and global (e.g. eutrophication, climate change) conditions.