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Registros recuperados: 102
Primeira ... 123456 ... Última
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Influence of CH4 and H2S availability on symbiont distribution, carbon assimilation and transfer in the dual symbiotic vent mussel Bathymodiolus azoricus ArchiMer
Riou, V.; Halary, S.; Duperron, S.; Bouillon, S.; Elskens, M.; Bettencourt, R.; Santos, R. S.; Dehairs, F.; Colaco, A..
High densities of mussels of the genus Bathymodiolus are present at hydrothermal vents of the Mid-Atlantic Ridge. It was previously proposed that the chemistry at vent sites would affect their sulphide- and methane-oxidizing endosymbionts' abundance. In this study, we confirmed the latter assumption using fluorescence in situ hybridization on Bathymodiolus azoricus specimens maintained in a controlled laboratory environment at atmospheric pressure with one, both or none of the chemical substrates. A high level of symbiosis plasticity was observed, methane-oxidizers occupying between 4 and 39% of total bacterial area and both symbionts developing according to the presence or absence of their substrates. Using (HCO3-)-C-13 in the presence of sulphide, or...
Tipo: Text Palavras-chave: Mid-atlantic ridge; Hydrocarbon-seep mussel; Deep-sea mussels; Hydrothermal-vent; Puteoserpentis bivalvia; Mytilidae; Methane; Endosymbionts; Bacteria; Metabolism.
Ano: 2008 URL: https://archimer.ifremer.fr/doc/00207/31865/30271.pdf
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Influence of Waiting Time after Insertion of Base Chamber into Soil on Produced Greenhouse Gas Fluxes Chilean J. Agric. Res.
Muñoz,Cristina; Saggar,Surinder; Berben,Peter; Giltrap,Donna; Jha,Neha.
The soil chamber technique is most commonly used for measuring gas exchange between soil surfaces and the atmosphere, to understand regulatory processes relevant to determine the greenhouse gas (GHG) emissions from soils and to improve the emissions inventory of agricultural systems. The chambers are inserted into the soil to avoid the lateral diffusion of the gases. However, soil disturbance caused by chamber insertion causes in degassing and can result in erroneous flux data from measurements made immediately following chamber insertion. Here we assess the effect of soil disturbance associated with the insertion of the chambers on nitrous oxide (N2O) and methane (CH4) fluxes with and without N fertilization, from a New Zealand pasture soil. We collected...
Tipo: Journal article Palavras-chave: Nitrous oxide; Methane; Agricultural soil; Soil biological processes; Gases monitoring.
Ano: 2011 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000400017
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Metabolism of CO and CH sub(4) by nitrifiers and the determination of the nitrification rate. ArchiMer
Morita, R; Jones, R.
The nitrifying bacteria were found to survive 24 weeks in the absence of ammonium without decreasing their number of cell size. Because H sub(2), CO, and CH sub(4) are present in the marine environment, these substrates were investigated as a possible source of the energy of maintenance for the nitrifying bacteria. super(14)CO and super(14)CH sub(4) were found to be oxidized by the nitrifiers. N-serve was found to inhibit the oxidation of CO. Using the nitrifiers' ability to oxide CO, a method for the determination of the nitrification rate was developed. The ability of nitrifiers to oxidize CO may play a significant role in the cycling of CO sub(2) in the marine environment. Whether CO and CH sub(4) oxidation play a role in the survival of nitrifiers in...
Tipo: Text Palavras-chave: Methane; Carbon dioxide; Survival; Bacteria; Nitrification; Nitrogen cycle; Oxidation; Carbon cycle; Biogeochemistry; Metabolism.
Ano: 1984 URL: http://archimer.ifremer.fr/doc/1984/acte-975.pdf
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Methane concentration in water column and in pore water of a coastal lagoon (Cabiúnas lagoon, Macaé, RJ, Brazil) BABT
Fonseca,André Luiz dos Santos; Minello,Murilo; Marinho,Claudio Cardoso; Esteves,Francisco de Assis.
The aim of this study was to evaluate methane concentration in water column and pore water at limnetic and littoral regions of a coastal lagoon. At the littoral region samples were taken from three monospecific macrophytes stands (Typha domingensis, Eleocharis interstincta and Potamogeton stenostachys). The methane concentration in the pore water at the littoral region was higher than the concentration found at the limnetic region in each fraction of the sediment. The higher methane concentration in the superficial fraction of the sediment (0-2 cm) was shown at the P. stenostachys stand (3.7 mM). It was the only significantly different (p<0.05) from the limnetic region. The pore water methane concentration increased with depth at the aquatic macrophytes...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Methane; Water column; Sediment; Aquatic macrophytes; Coastal lagoons.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132004000200018
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Methane emission from a flooded rice field under pre-germinated system Ciência Rural
Lima,Magda Aparecida de; Vieira,Rosana Faria; Frighetto,Rosa Toyoko Shiraishi; Luiz,Alfredo José Barreto; Villela,Omar Vieira.
ABSTRACT: Local greenhouse gas flow measurement studies have been encouraged at a global level as a subsidy for national and state inventories. This study aimed to evaluate the seasonal methane emission during the 2008/2009 harvest, from an irrigated rice plantation, under pre-germinated system, in the municipality of Tremembé, State of São Paulo, using the static chamber technique and gas chromatography. The study showed high seasonal emission of methane (CH4) for the studied area, probably due to the long flooding period. It was estimated the CH4 emission factor (6.51 kg CH4 ha-1 dia-1), the partial global warming potential (pGWP, 27.2 Mg CO2eq growing season-1 ha-1) and the yield-scaled pGWP (YpGWP, 3.9 kg CO2eq kg-1 grain).
Tipo: Info:eu-repo/semantics/article Palavras-chave: Flooded rice; Pre-germinated system; Methane.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782019001100201
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Methane in shallow subsurface sediments at the landward limit of the gas hydrate stability zone offshore Western Svalbard ArchiMer
Graves, Carolyn A.; James, Rachael H.; Sapart, Celia Julia; Stott, Andrew W.; Wright, Ian C.; Berndt, Christian; Westbrook, Graham; Connelly, Douglas P..
Offshore western Svalbard plumes of gas bubbles rise from the seafloor at the landward limit of the gas hydrate stability zone (LLGHSZ; ∼400 m water depth). It is hypothesized that this methane may, in part, come from dissociation of gas hydrate in the underlying sediments in response to recent warming of ocean bottom waters. To evaluate the potential role of gas hydrate in the supply of methane to the shallow subsurface sediments, and the role of anaerobic oxidation in regulating methane fluxes across the sediment-seawater interface, we have characterised the chemical and isotopic compositions of the gases and sediment pore waters. The molecular and isotopic signatures of gas in the bubble plumes (C1/C2+ = 1 × 104; δ13C-CH4 = -55 to -51 ‰; δD-CH4 = -187...
Tipo: Text Palavras-chave: Methane; Seafloor sediments; Gas hydrate; Offshore Svalbard; Seabed fluxes; Anaerobic oxidation.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00358/46914/46819.pdf
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Methane-derived stromatolitic carbonate crust from an active fluid seepage in the western basin of the Sea of Marmara: mineralogical, isotopic and molecular geochemical characterization ArchiMer
Akhoudas, C.; Chevalier, N.; Blanc-valleron, M. -m.; Klein, V.; Mendez-millan, M.; Demange, J.; Dalliah, S.; Rommevaux, V.; Boudouma, O.; Pierre, C.; Ruffine, Livio.
Cold seeps along the North Anatolian fault in the Sea of Marmara (Turkey) were explored during submersible dives of the Marsite cruise in November 2014 when sediments, pore waters and carbonate crusts were sampled at active fluid seeping sites. In this study, we investigate the mineralogy, carbon and oxygen isotopic compositions and the lipid biomarkers of a carbonate crust from the western Tekirdağ basin of the Sea of Marmara. This crust exhibits a laminated domal structure that resembles stromatolite. The mineralogy of authigenic seep-carbonate is mostly represented by aragonite associated with minor amounts of high-magnesian calcite. The abundance of pyrite associated with the authigenic seep-carbonate points to very intense bacterial sulfate reduction....
Tipo: Text Palavras-chave: Marmara Sea; Tekirdag Basin; Methane; Authigenic seep-carbonate; Sulfate reduction; Anaerobic oxidation of methane; Stromatolitic structure; Stable isotopes; Lipid biomarkers.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00417/52857/53764.pdf
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Methanization potential of anaerobic biodigestion of solid food waste AGRIAMBI
Oliveira,Laís R. G. de; Santos Filho,Derovil A. dos; Vasconcelos,Kaline C.; Lucena,Talita V. de; Jucá,José F. T.; Santos,André F. de M. S..
ABSTRACT Anaerobic biodigestion of solid and semi-solid wastes has been widely used for the treatment of these residues and methane production; however, during the process (more specifically in the acidogenic phase), there is a tendency of pH reduction, an unfavorable condition to methanogenic bacteria. Thus, the present work aims to evaluate the methanization potential of an agroindustrial anaerobic granular sludge (AIS) from UASB (Upflow Anaerobic Sludge Blanket) reactor, individually and biodigested with food waste (FW) from the University Restaurant of the Federal University of Pernambuco with buffering agent (AIS + FW + b) and without it (AIS + FW). After the laboratory tests, the AIS + FW + b configuration obtained a cumulative methane production...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Biodegradation; Methane; PH; Inoculum.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000100069
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Methanogenesis in an impacted and two dystrophic coastal lagoons (Macaé, Brazil) BABT
Furtado,André Luiz dos Santos; Casper,Peter; Esteves,Francisco de Assis.
This study investigated the methanogenic activity in sediment of the Imboacica (human impacted), Cabiúnas and Comprida coastal lagoons in Rio de Janeiro State (Brazil). Methane was not detected in water and sediment samples from the three lagoons. The measured nutrient concentrations in the pore-water indicated that methanogens activity was not limited by nutrients. Methanogenic activity was not detected under in vitro conditions, indicating that terminal organic carbon mineralisation via methanogenesis was negligible for the top 6 cm of sediment at the sampling time.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Coastal lagoon; Methane; Sediment; Nutrients.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000200011
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Modern sedimentation and geochemical imprints in sediments from the NW Madagascar margin ArchiMer
Pastor, Lucie; Brandily, Christophe; Schmidt, S.; Miramontes, E.; Péron, Maela; Appere, Dennis; Chéron, Sandrine; Boissier, Audrey; Jouet, Gwenael.
The NW Madagascar continental margin receives high loads of terrigenous particulate organic matter during the wet season and especially linked to extreme events, originating from two major rivers, the Betsiboka and the Mahavavy Rivers. This particulate matter contains a high content of iron minerals from the weathering of red ferruginous/ferralitic soils of Madagascar. The presence of pockmarks, i.e. gas or fluid expulsion features on the continental slope, testifies to past/present methane migration through the sedimentary column, associated with early diagenetic processes. This study globally aims at deciphering the interactions between episodic sedimentation and geochemical processes influenced by fluids upward migration, using a sediment trap mooring...
Tipo: Text Palavras-chave: Episodic sedimentation; Madagascar margin; Betsiboka river; Mahavavy river; Progradation; Methane; Geochemistry; Sediment.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00628/73964/73323.pdf
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Multidisciplinary investigation on cold seeps with vigorous gas emissions in the Sea of Marmara (MarsiteCruise): Strategy for site detection and sampling and first scientific outcome ArchiMer
Ruffine, Livio; Ondreas, Helene; Blanc-valleron, Marie-madeleine; Teichert, Barbara M. A.; Scalabrin, Carla; Rinnert, Emmanuel; Birot, Dominique; Croguennec, Claire; Ponzevera, Emmanuel; Pierre, Catherine; Donval, Jean-pierre; Alix, Anne-sophie; Germain, Yoan; Bignon, Laurent; Etoubleau, Joel; Caprais, Jean-claude; Knoery, Joel; Lesongeur, Francoise; Thomas, Bastien; Roubi, Angelique; Legoix, Ludovic Nicolas; Burnard, Pete; Chevalier, Nicolas; Lu, Hailong; Dupre, Stephanie; Fontanier, Christophe; Dissard, Delphine; Olgun, Nazli; Yang, Hailin; Strauss, Harald; Ozaksoy, Volkan; Perchoc, Jonathan; Podeur, Christian; Tarditi, Corinne; Ozbeki, Eyyup; Guyader, Vivien; Marty, Bernard; Madre, David G; Pitel-roudaut, Mathilde; Grall, Celine; Embriaco, Davide; Polonia, Mina; Gasperini, Lucas; Cagatay, M. Namik; Henry, Pierre; Geli, Louis.
MarsiteCruise was undertaken in October/November 2014 in the Sea of Marmara to gain detailed insight into the fate of fluids migrating within the sedimentary column and partially released into the water column. The overall objective of the project was to achieve a more global understanding of cold-seep dynamics in the context of a major active strike-slip fault. Five remotely operated vehicle (ROV) dives were performed at selected areas along the North Anatolian Fault and inherited faults. To efficiently detect, select and sample the gas seeps, we applied an original procedure. It combines sequentially (1) the acquisition of ship-borne multibeam acoustic data from the water column prior to each dive to detect gas emission sites and to design the tracks of...
Tipo: Text Palavras-chave: Acoustic survey; Authigenic carbonates; Biogeochemistry; Chemical analyses; Cold seeps; Dissolved major elements; Fluid seepage; Geology; In situ Raman analysis; Methane; ROV dives.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00433/54434/55783.pdf
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New insigths on the metabolic diversity among the epibiotic microbial communitiy of the hydrothermal shrimp Rimicaris exoculata ArchiMer
Zbinden, M; Shillito, B; Le Bris, Nadine; De Montlaur, C; Roussel, Erwan; Guyot, F; Gaill, F; Cambon-bonavita, Marie-anne.
The Rimicaris exoculata dominates the megafauna of some of the Mid Atlantic ridge hydrothermal vent sites. This species harbors a rich community of bacterial epibionts inside its gill chamber. Literature data indicate that a single 16S rRNA phylotype dominates this epibiotic community, and is assumed to be a sulfide-oxidizing bacteria. However attempts Of Cultivation were not successful and did not allow to confirm it. The aim of our study was to test the hypothesis of sulfide oxidation in the gill chamber, by a multidisciplinary approach, using in vivo experiments at in situ pressure in the presence of sulfide, microscopic observations and a molecular survey. Morphology of microorganisms, before and after treatment, was analyzed to test the effect of...
Tipo: Text Palavras-chave: Sulfur; Methane; Iron; Intracellular granules; Hydrothermal vent shrimp; High pressure experiments.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-4563.pdf
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Origin of Short-Chain Organic Acids in Serpentinite Mud Volcanoes of the Mariana Convergent Margin ArchiMer
Eickenbusch, Philip; Takai, Ken; Sissman, Olivier; Suzuki, Shino; Menzies, Catriona; Sakai, Sanae; Sansjofre, Pierre; Tasumi, Eiji; Bernasconi, Stefano M.; Glombitza, Clemens; Jorgensen, Bo Barker; Morono, Yuki; Lever, Mark Alexander.
Serpentinitic systems are potential habitats for microbial life due to frequently high concentrations of microbial energy substrates, such as hydrogen (H-2), methane (CH4), and short-chain organic acids (SCOAs). Yet, many serpentinitic systems are also physiologically challenging environments due to highly alkaline conditions (pH > 10) and elevated temperatures (>80 degrees C). To elucidate the possibility of microbial life in deep serpentinitic crustal environments, International Ocean Discovery Program (IODP) Expedition 366 drilled into the Yinazao, Fantangisfia, and Asut Tesoru serpentinite mud volcanoes on the Mariana Forearc. These mud volcanoes differ in temperature (80, 150, 250 degrees C, respectively) of the underlying subducting slab, and...
Tipo: Text Palavras-chave: Limits of life; Deep biosphere; Serpentinization; Abiotic synthesis; Formate; Acetate; Methane; International Ocean Discovery Program.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00637/74919/75981.pdf
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Origine et circulation des fluides dans les sédiments des marges. Contribution de l'hélium et du méthane dans la compréhension des processus. Étude de 2 zones actives ArchiMer
Chaduteau, Carine.
Fluid migration is a very important process in marine sediments on margins. Studying fluids is fundamental to constrain the energy potential of margins. Methane is the predominant gas in marine sediments, deriving primarily from the degradation of organic matter. However methane could be also generated through the serpentinization of mantle rocks underlying the sedimentary cover in some specific geodynamical settings. One way to test this hypothesis is to use helium isotopes, which are known to be powerful tracers of the fluid-mantle interaction. To this purpose, a new method has been developed for the sampling and the quantitative extraction of dissolved helium from sediment pore-waters. During the Zairov2 and Vicking cruises, samples were collected in...
Tipo: Text Palavras-chave: Mantle; Serpentinization; Advection; Mud volcano; Pockmark; Methane; Helium; Fluid; Margin; Manteau; Serpentinisation; Advection; Volcan de boue; Pockmark; Méthane; Hélium; Fluide; Marge.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/these-3724.pdf
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Performance of UASB reactors in two stages followed by post-treatment with activated sludge in wastewater batch of wet-processed coffee REA
Bruno,Marcelo; Oliveira,Roberto A. de.
In this study it was evaluated the efficiency of the treatment of wet-processed coffee wastewater in upflow anaerobic sludge blanket (UASB) reactors in two stages, in bench scale, followed by post-treatment with activated sludge in batch. The first UASB reactor was submitted to an hydraulic retention time (HRT) of 6.2 d and organic loading rates (OLR) of 2.3 and 4.5g CODtotal (L d)-1, and the second UASB reactor to HRT of 3.1 d with OLR of 0.4 and 1.4g CODtotal (L d)-1. The average values of the affluent CODtotal increased from 13,891 to 27,926mg L-1 and the average efficiencies of removal of the CODtotal decreased from 95 to 91%, respectively, in the UASB reactors in two stages. The volumetric methane production increased from 0.274 to 0.323L CH4 (L...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Anaerobic digestion; Methane; Nitrogen; Phosphorus; Phenols.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162013000400020
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Pithecellobium dulce, Tagetes erecta and Cosmos bipinnatus on reducing enteric methane emission by dairy cows Ciência Rural
Pineda,Gloria Stefanny Hernández; Beltrán,Paulina Elizabeth Pedraza; Benaouda,Mohammed; García,José Manuel Palma; Nova,Francisca Avilés; Molina,Luisa; Ortega,Octavio Alonso Castelán.
ABSTRACT: The aim of the present research was to evaluate the effect of Pithecellobium dulce, Tagetes erecta and Cosmos bipinnatus on methane emission, milk yield and dry matter intake in dairy cattle. A 4×4 Latin square experimental design was employed, using four multiparous Holstein cows of 553±72.4kg body weight, at mid lactation and average milk yield of 17.3±3kg/day. The experiment lasted 92 days, divided into four experimental periods of 23 days each. All cows had free access to maize and alfalfa silage in a 50:50 proportion, 4kg of concentrate/day and ad libitum access to water. Treatments consisted in supplementation of 0.5kg/day of the experimental plants, with one control treatment without supplementation. Each cow received one of each treatment...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Methane; Cattle; Climate change; Mitigation; Tannins.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782018001000650
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Protein metabolism, feed energy partitioning, behavior patterns and plasma cortisol in Nellore steers with high and low residual feed intake R. Bras. Zootec.
Gomes,Rodrigo da Costa; Sainz,Roberto Daniel; Leme,Paulo Roberto.
The objective was to evaluate protein turnover, nitrogen balance, feed energy partitioning, behavior patterns and plasma cortisol in Nellore (B. indicus) cattle with high and low residual feed intake (RFI = actual minus expected dry matter intake). Seventy-two Nellore steers (16 to 21 months-old, 334±19 kg initial body weight) were fed a feedlot diet for 70 days ad libitum. Daily dry matter intake (DMI) and average daily gain (ADG) were recorded individually and RFI was calculated. The 12 steers of lowest (Low-RFI, most efficient) RFI and the 12 ones of highest RFI (High-RFI, least efficient) were evaluated with respect to their behavior patterns and plasma cortisol concentration. Urine was collected for determination of daily 3-methylhistidine excretion...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Bos indicus; Feed efficiency; Methane; Net feed intake; 3-methyl-histidine; Zebu.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982013000100007
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Role of pockmarks in diversity and species assemblages of coastal macrobenthic communities ArchiMer
Dubois, Stanislas; Derian, Francois; Caisey, Xavier; Rigolet, Carinne; Caprais, Jean-claude; Thiebaut, Eric.
We used existing bathymetric data to study the macrofauna of a geophysical pockmark field restricted to a benthic habitat engineered by the tubiculous amphipod Haploops nirae in South Brittany (France). Stations inside and outside pockmarks of different morphometric characteristics (location, size, depression depth) were sampled for macrofauna and environmental parameters (sediment characteristics, organic matter, chl a, hydrogen sulfide and methane concentrations). Diversity indices showed higher species richness inside pockmarks, especially for species with medium to high abundances. Most sediment cores showed low methane but high hydrogen sulfide concentrations. We hypothesised that after eruption, the remaining residual methane from pockmark sediments...
Tipo: Text Palavras-chave: Benthic habitat; Biodiversity; Succession; Amphipod; Haploops; South Brittany; Sulfide; Methane; Environmental factors.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00272/38333/36576.pdf
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Seafloor geological studies above active gas chimneys off Egypt (Central nile deep sea fan) ArchiMer
Dupre, Stephanie; Woodside, J; Foucher, Jean-paul; De Lange, G; Mascle, J; Boetius, A; Mastalerz, V; Stadnitskaia, A; Ondreas, Helene; Huguen, C; Harmegnies, Francois; Gontharet, Swanne; Loncke, L; Deville, E; Niemann, H; Omoregie, E; Olu, Karine; Fiala Medioni, A; Dahlmann, A; Caprais, Jean-claude; Prinzhofer, A; Sibuet, Myriam; Pierre, C; Damste, J.
Four mud volcanoes of several kilometres diameter named Amon, Osiris, Isis, and North Alex and located above gas chimneys on the Central Nile Deep Sea Fan, were investigated for the first time with the submersible Nautile. One of the objectives was to characterize the seafloor morphology and the seepage activity across the mud volcanoes. The seepage activity was dominated by emissions of methane and heavier hydrocarbons associated with a major thermal contribution. The most active parts of the mud volcanoes were highly gas-saturated (methane concentrations in the water and in the sediments, respectively, of several hundreds of nmol/L and several mmol/L of wet sediment) and associated with significantly high thermal gradients (at 10 m below the seafloor,...
Tipo: Text Palavras-chave: Seafloor morphology; Methane; Authigenic carbonate precipitation; Gas chimneys; Mud breccia; Mud volcanoes; Fluid seepage; Nile fan.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-4455.pdf
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Shallow gas hydrate accumulations at a Nigerian deep‐water pockmark ‐ Quantities and dynamics ArchiMer
Pape, Thomas; Ruffine, Livio; Hong, Wei‐li; Sultan, Nabil; Riboulot, Vincent; Peters, Carl A.; Kölling, Martin; Zabel, Matthias; Garziglia, Sebastien; Bohrmann, Gerhard.
The evolution of submarine pockmarks is often related to the ascent of fluid from the subsurface. For pockmarks located within the gas hydrate stability zone, methane oversaturation can result in the formation of gas hydrates in the sediment. A ca. 600 m‐wide sea floor depression in deep‐waters offshore Nigeria, Pockmark A, was investigated for distributions and quantities of shallow gas hydrates, origins of hydrocarbons and time elapsed since the last major fluid ascent event. For the first time, pressure coring of shallow sediments and drilling of more than 50‐m‐long cores with the sea floor drill rig MARUM‐MeBo70 were conducted in this pockmark. Unusually high hydrate saturations of up to 51% of pore volume in the uppermost 2.5 meters of sediment in the...
Tipo: Text Palavras-chave: Pockmark; Gas hydrate; Methane; MeBo; Pressure coring; Pore water modeling.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00643/75491/76344.pdf
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