Deep Sequencing of Myxilla (Ectyomyxilla) methanophila, an Epibiotic Sponge on Cold-Seep Tubeworms, Reveals Methylotrophic, Thiotrophic, and Putative Hydrocarbon-Degrading Microbial Associations

KAUST Repository

Arellano, Shawn M.; Lee, Onon; Lafi, Feras Fawzi; Yang, Jiangke; Wang, Yong; Young, Craig; Qian, Peiyuan

2012-01-01

The encrusting sponge Myxilla (Ectyomyxilla) methanophila (Poecilosclerida: Myxillidae) is an epibiont on vestimentiferan tubeworms at hydrocarbon seeps on the upper Louisiana slope of the Gulf of Mexico. It has long been suggested that this sponge

Identification of Novel Methane-, Ethane-, and Propane-Oxidizing Bacteria at Marine Hydrocarbon Seeps by Stable Isotope Probing ▿ †

Science.gov (United States)

Redmond, Molly C.; Valentine, David L.; Sessions, Alex L.

2010-01-01

Marine hydrocarbon seeps supply oil and gas to microorganisms in sediments and overlying water. We used stable isotope probing (SIP) to identify aerobic bacteria oxidizing gaseous hydrocarbons in surface sediment from the Coal Oil Point seep field located offshore of Santa Barbara, California. After incubating sediment with 13C-labeled methane, ethane, or propane, we confirmed the incorporation of 13C into fatty acids and DNA. Terminal restriction fragment length polymorphism (T-RFLP) analysis and sequencing of the 16S rRNA and particulate methane monooxygenase (pmoA) genes in 13C-DNA revealed groups of microbes not previously thought to contribute to methane, ethane, or propane oxidation. First, 13C methane was primarily assimilated by Gammaproteobacteria species from the family Methylococcaceae, Gammaproteobacteria related to Methylophaga, and Betaproteobacteria from the family Methylophilaceae. Species of the latter two genera have not been previously shown to oxidize methane and may have been cross-feeding on methanol, but species of both genera were heavily labeled after just 3 days. pmoA sequences were affiliated with species of Methylococcaceae, but most were not closely related to cultured methanotrophs. Second, 13C ethane was consumed by members of a novel group of Methylococcaceae. Growth with ethane as the major carbon source has not previously been observed in members of the Methylococcaceae; a highly divergent pmoA-like gene detected in the 13C-labeled DNA may encode an ethane monooxygenase. Third, 13C propane was consumed by members of a group of unclassified Gammaproteobacteria species not previously linked to propane oxidation. This study identifies several bacterial lineages as participants in the oxidation of gaseous hydrocarbons in marine seeps and supports the idea of an alternate function for some pmoA-like genes. PMID:20675448

Benthic Community Structure and Sediment Geochemical Properties at Hydrocarbon Seeps Along the Continental Slope of the Western North Atlantic

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Demopoulos, A. W.; Bourque, J. R.; Brooke, S.

2015-12-01

Hydrocarbon seeps support distinct benthic communities capable of utilizing reduced chemical compounds for nutrition. In recent years, methane seepage has been increasingly documented along the continental slope of the U.S. Atlantic margin. In 2012 and 2013, two seeps were investigated in this region: a shallow site near Baltimore Canyon (410-450 m) and a deep site near Norfolk Canyon (1600 m). Both sites contain extensive mussel beds and microbial mats. Sediment cores and grab samples were collected to quantify the abundance, diversity, and community structure of benthic macrofauna (>300 mm) in relationship to the associated sediment environment (organic carbon and nitrogen, stable isotopes 13C and 15N, grain size, and depth) of mussel beds, mats, and slope habitats. Macrofaunal densities in microbial mats were four times greater than those present in mussel beds and slope sediments. Macrofaunal communities were distinctly different both between depths and among habitat types. Specifically, microbial mat sediments were dominated by the annelid families Dorvilleidae, Capitellidae, and Tubificidae, while mussel habitats had higher proportions of crustaceans. Diversity was lower in Baltimore microbial mat habitats, but higher in mussel and slope sediments compared to Norfolk seep habitats found at deeper depths. Multivariate statistical analysis identified sediment carbon:nitrogen (C:N) ratios and 13C values as important variables for structuring the macrofaunal communities. Higher C:N ratios were present within microbial mat habitats and depleted 13C values occurred in sediments adjacent to mussel beds found in Norfolk Canyon seeps. Differences in the quality and source of organic matter present in the seep habitats are known to be important drivers in macrofaunal community structure and associated food webs. The multivariate analysis provides new insight into the relative importance of the seep sediment quality in supporting dense macrofaunal communities compared

Carbonate-cemented hardgrounds: a subtle indicator for seep activity offshore Humboldt Bay

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Shapiro, R. S.; Bazard, D.

2007-12-01

Active hydrocarbon seeps are common in the accretionary prism of the Cascadia subduction zone. In Humboldt County, California, the prism is exposed at the surface as a series of fault-propagated anticlines trending NW-SE. Offshore of the town of Samoa, a northwest-plunging anticline is breached at approximately 40 meters water depth, allowing hydrocarbons to seep out to the seafloor (40.8° N, 124.25° W). The assumed microbial activity at the seep leads to the production of interstitial carbonate cements forming hardgrounds. Cementation is pervasive and blocks eroded from the seep area of the seabed are transported onshore during storm events. Blocks collected from the beach range from 3--40 centimeters across. The sediments of the blocks are palimpsest transgressive deposits composed mostly of immature fine sand, but ranging from very fine to rounded gravels 4 cm diameter. Cementation is not dependent on grain size as all of the sediment sizes are cemented. In rare void spaces, a concentric banding of cements is obvious. The interstitial cements preserve original sedimentary structures including graded beds and high-angle cross-beds. Centimeter-scale subspherical concretions occur on the undersides of some blocks. There is no disruption of bedding in contrast to other seeps where the expulsion of gas can create pockmarks, brecciation, and other disturbances. Unlike the better studied seeps farther south in the Eel River basin, the Samoa seeps do not seem to host a rich chemosynthetic fauna. Whole and (mostly) fragmented shells preserved by the cemented sands represent a typical benthic inner shelf community including Dendraster, Macoma, and Olivella. Burrows preserved in the sands are largely horizontal and 1--2 mm diameter. Seep carbonate-cemented hardgrounds are less well studied then the more obvious meter-scale 'chemoherm' deposits. However, they may be more prevalent in the rock record and provide a new proxy for locating ancient seeps and hydrocarbon

Bioassays with terrestrial and aquatic species as monitoring tools of hydrocarbon degradation.

Science.gov (United States)

Bori, Jaume; Vallès, Bettina; Ortega, Lina; Riva, Maria Carme

2016-09-01

In this study chemical analyses and ecotoxicity tests were applied for the assessment of a heavily hydrocarbon-contaminated soil prior and after the application of a remediation procedure that consisted in the stimulation of soil autochthonous populations of hydrocarbon degraders in static-ventilated biopiles. Terrestrial bioassays were applied in mixtures of test soils and artificial control soil and studied the survival and reproduction of Eisenia fetida and the avoidance response of E. fetida and Folsomia candida. Effects on aquatic organisms were studied by means of acute tests with Vibrio fischeri, Raphidocelis subcapitata, and Daphnia magna performed on aqueous elutriates from test soils. The bioremediation procedure led to a significant reduction in the concentration of hydrocarbons (from 34264 to 3074 mg kg(-1), i.e., 91 % decrease) and toxicity although bioassays were not able to report a percentage decrease of toxicity as high as the percentage reduction. Sublethal tests proved the most sensitive terrestrial bioassays and avoidance tests with earthworms and springtails showed potential as monitoring tools of hydrocarbon remediation due to their high sensitivity and short duration. The concentrations of hydrocarbons in water extracts from test soils were 130 and 100 μg L(-1) before and after remediation, respectively. Similarly to terrestrial tests, most aquatic bioassays detected a significant reduction in toxicity, which was almost negligible at the end of the treatment. D. magna survival was the most affected by soil elutriates although toxicity to the crustacean was associated to the salinity of the samples rather than to the concentration of hydrocarbons. Ecotoxicity tests with aqueous soil elutriates proved less relevant in the assessment of hydrocarbon-contaminated soils due to the low hydrosolubility of hydrocarbons and the influence of the physicochemical parameters of the aquatic medium.

Deep Sequencing of Myxilla (Ectyomyxilla) methanophila, an Epibiotic Sponge on Cold-Seep Tubeworms, Reveals Methylotrophic, Thiotrophic, and Putative Hydrocarbon-Degrading Microbial Associations

KAUST Repository

Arellano, Shawn M.

2012-10-11

The encrusting sponge Myxilla (Ectyomyxilla) methanophila (Poecilosclerida: Myxillidae) is an epibiont on vestimentiferan tubeworms at hydrocarbon seeps on the upper Louisiana slope of the Gulf of Mexico. It has long been suggested that this sponge harbors methylotrophic bacteria due to its low δ13C value and high methanol dehydrogenase activity, yet the full community of microbial associations in M. methanophila remained uncharacterized. In this study, we sequenced 16S rRNA genes representing the microbial community in M. methanophila collected from two hydrocarbon-seep sites (GC234 and Bush Hill) using both Sanger sequencing and next-generation 454 pyrosequencing technologies. Additionally, we compared the microbial community in M. methanophila to that of the biofilm collected from the associated tubeworm. Our results revealed that the microbial diversity in the sponges from both sites was low but the community structure was largely similar, showing a high proportion of methylotrophic bacteria of the genus Methylohalomonas and polycyclic aromatic hydrocarbon (PAH)-degrading bacteria of the genera Cycloclasticus and Neptunomonas. Furthermore, the sponge microbial clone library revealed the dominance of thioautotrophic gammaproteobacterial symbionts in M. methanophila. In contrast, the biofilm communities on the tubeworms were more diverse and dominated by the chemoorganotrophic Moritella at GC234 and methylotrophic Methylomonas and Methylohalomonas at Bush Hill. Overall, our study provides evidence to support previous suggestion that M. methanophila harbors methylotrophic symbionts and also reveals the association of PAH-degrading and thioautotrophic microbes in the sponge. © 2012 Springer Science+Business Media New York.

Deep sequencing of Myxilla (Ectyomyxilla) methanophila, an epibiotic sponge on cold-seep tubeworms, reveals methylotrophic, thiotrophic, and putative hydrocarbon-degrading microbial associations.

Science.gov (United States)

Arellano, Shawn M; Lee, On On; Lafi, Feras F; Yang, Jiangke; Wang, Yong; Young, Craig M; Qian, Pei-Yuan

2013-02-01

The encrusting sponge Myxilla (Ectyomyxilla) methanophila (Poecilosclerida: Myxillidae) is an epibiont on vestimentiferan tubeworms at hydrocarbon seeps on the upper Louisiana slope of the Gulf of Mexico. It has long been suggested that this sponge harbors methylotrophic bacteria due to its low δ(13)C value and high methanol dehydrogenase activity, yet the full community of microbial associations in M. methanophila remained uncharacterized. In this study, we sequenced 16S rRNA genes representing the microbial community in M. methanophila collected from two hydrocarbon-seep sites (GC234 and Bush Hill) using both Sanger sequencing and next-generation 454 pyrosequencing technologies. Additionally, we compared the microbial community in M. methanophila to that of the biofilm collected from the associated tubeworm. Our results revealed that the microbial diversity in the sponges from both sites was low but the community structure was largely similar, showing a high proportion of methylotrophic bacteria of the genus Methylohalomonas and polycyclic aromatic hydrocarbon (PAH)-degrading bacteria of the genera Cycloclasticus and Neptunomonas. Furthermore, the sponge microbial clone library revealed the dominance of thioautotrophic gammaproteobacterial symbionts in M. methanophila. In contrast, the biofilm communities on the tubeworms were more diverse and dominated by the chemoorganotrophic Moritella at GC234 and methylotrophic Methylomonas and Methylohalomonas at Bush Hill. Overall, our study provides evidence to support previous suggestion that M. methanophila harbors methylotrophic symbionts and also reveals the association of PAH-degrading and thioautotrophic microbes in the sponge.

Mass balance constraints on the sources of the petrogenic hydrocarbon background in offshore sediments of Prince William Sound and the Gulf of Alaska

International Nuclear Information System (INIS)

Page, D.S.; Boehm, P.D.; Douglas, G.S.; Brown, J.S.; Bence, A.E.; Burns, W.A.

2000-01-01

A comprehensive sampling program was conducted in 1999 in the offshore sediments of Prince William Sound and the Gulf of Alaska to verify a recent claim that eroding coal beds are the source of petrogenic hydrocarbons background in the area. Samples taken in 1993 and 1994 were reanalyzed to determine concentrations of polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers. Three Bering River coal samples plus 10 archived source-rock and 3 archived Gulf of Alaska seep and field oil samples from exploration activities in the 1960s and 1970s were also analyzed. The linear combination of the analyte distributions of 18 representative sources that most likely matched the compositions of each sample was derived using the least-squares method. Some of the potential contributing sources which were examined for this study included seep oil, eroding source rocks, eroding coal beds, glacial flour, recent terrestrial sources and human activity. It was determined that the recent claim was incorrect. Eroding Tertiary petroleum source rocks and residues of seep oils are the main sources of hydrocarbon background in the area, rather than area coals or residues from the Exxon Valdez oil spill. 10 refs., 2 tabs., 3 figs

Metagenomes from two microbial consortia associated with Santa Barbara seep oil.

Science.gov (United States)

Hawley, Erik R; Malfatti, Stephanie A; Pagani, Ioanna; Huntemann, Marcel; Chen, Amy; Foster, Brian; Copeland, Alexander; del Rio, Tijana Glavina; Pati, Amrita; Jansson, Janet R; Gilbert, Jack A; Tringe, Susannah Green; Lorenson, Thomas D; Hess, Matthias

2014-12-01

The metagenomes from two microbial consortia associated with natural oils seeping into the Pacific Ocean offshore the coast of Santa Barbara (California, USA) were determined to complement already existing metagenomes generated from microbial communities associated with hydrocarbons that pollute the marine ecosystem. This genomics resource article is the first of two publications reporting a total of four new metagenomes from oils that seep into the Santa Barbara Channel. Copyright © 2014 Elsevier B.V. All rights reserved.

Out of the dark: Transitional subsurface-to-surface microbial diversity in a terrestrial serpentinizing seep (Manleluag, Pangasinan, the Philippines

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Kristin eWoycheese

2015-02-01

Full Text Available In the Zambales ophiolite range terrestrial serpentinizing fluid seeps host diverse microbial assemblages. The fluids fall within the profile of Ca2+-OH--type waters, indicative of active serpentinization, and are low in dissolved inorganic carbon (<0.5 ppm. Influx of atmospheric carbon dioxide affects the solubility of calcium carbonate as distance from the source increases, triggering the formation of meter-scale travertine terraces. Samples were collected at the source and along the outflow channel to determine subsurface microbial community response to surface exposure. DNA was extracted and submitted for high-throughput 16S rRNA gene sequencing on the Illumina MiSeq platform. Taxonomic assignment of the sequence data indicates that 8.1% of the total sequence reads at the source of the seep affiliate with the genus Methanobacterium. Other major classes detected at the source include anaerobic taxa such as Bacteroidetes (40.7% of total sequence reads and Firmicutes (19.1% of total reads. Hydrogenophaga spp. increase in relative abundance as redox potential increases. At the carbonate terrace, 45% of sequence reads affiliate with Meiothermus spp. Taxonomic observations and geochemical data suggest that several putative metabolisms may be favorable, including hydrogen oxidation, H2-associated sulfur cycling, methanogenesis, methanotrophy, nitrogen fixation, ammonia oxidation, denitrification, nitrate respiration, methylotrophy, carbon monoxide respiration, and ferrous iron oxidation, based on capabilities of nearest known neighbors. Scanning electron microscopy and energy dispersive X-ray spectroscopy suggest that microbial activity produces chemical and physical traces in the precipitated carbonates forming downstream of the seep’s source. These data provide context for future serpentinizing seep ecosystem studies, particularly with regards to tropical biomes.

Microbiology and geochemistry of hydrocarbon-rich sediments erupted from the deep geothermal Lusi site, Indonesia

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Krüger, Martin; Straten, Nontje; Mazzini, Adriano; Scheeder, Georg; Blumenberg, Martin

2016-04-01

The Lusi eruption represents one of the largest ongoing sedimentary hosted geothermal systems, which started in 2006 following an earthquake on Java Island. Since then it has been producing hot and hydrocarbon rich mud from a central crater with peaks reaching 180.000 m3 per day. Numerous investigations focused on the study of offshore microbial colonies that commonly thrive at offshore methane and oil seeps and mud volcanoes, however very little has been done for onshore seeping structures. Lusi represents a unique opportunity to complete a comprehensive study of onshore microbial communities fed by the seepage of CH4 as well as of heavier liquid hydrocarbons originating from one or more km below the surface. While the source of the methane at Lusi is clear (Mazzini et al., 2012), the origin of the seeping oil, either form the deep mature Eocene Ngimbang (type II kerogen) or from the less mature Pleistocene Upper Kalibeng Fm. (type III kerogen), is still discussed. In the framework of the Lusi Lab project (ERC grant n° 308126) we analysed an oil film and found that carbon preference indices among n-alkanes, sterane and hopane isomers (C29-steranes: 20S/(20S+20R) and α,β-C32 Hopanes (S/(S+R), respectively) are indicative of a low thermal maturity of the oil source rock (~0.5 to 0.6 % vitrinite reflectance equivalents = early oil window maturity). Furthermore, sterane distributions, the pristane to phytane ratio and a relatively high oleanane index, which is an indication of an angiosperm input, demonstrate a strong terrestrial component in the organic matter. Together, hydrocarbons suggest that the source of the oil film is predominantly terrestrial organic matter. Both, source and maturity estimates from biomarkers, are in favor of a type III organic matter source and are therefore suggestive of a mostly Pleistocene Upper Kalibeng Fm. origin. We also conducted a sampling campaign at the Lusi site collecting samples of fresh mud close to the erupting crater

Degradation of Total Petroleum Hydrocarbon in Phytoremediation Using Terrestrial Plants

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Mushrifah Idris

2014-06-01

Full Text Available This study focused on the total petroleum hydrocarbon (TPH degradation in phytoremediation of spiked diesel in sand. The diesel was added to the sand that was planted with terrestrial plants. Four selected terrestrial plants used were Paspalum vaginatum Sw, Paspalums crobiculatum L. varbispicatum Hack, Eragrotis atrovirens (Desf. Trin. ex Steud and Cayratia trifolia (L. Domin since all the plants could survive at a hydrocarbon petroleum contaminated site in Malaysia. The samplings were carried out on Day 0, 7, 14, 28, 42 and 72. The analysis of the TPH was conducted by extracting the spiked sand using ultrasonic extraction. The determination of the TPH concentration in the sand was performed using GC-FID. The degradation of TPH depends on the plant species and time of exposure. The highest percentage degradation by P. vaginatum, P. scrobiculatum, E. atrovirens and C. trifolia were 91.9, 74.0, 68.9 and 62.9%, respectively. In conclusion, the ability to degrade TPH by plants were P. vaginatum > P. scrobiculatum > E. atrovirens> C. trifolia.

Discovery of asphalt seeps in the deep Southwest Atlantic off Brazil

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Fujikura, Katsunori; Yamanaka, Toshiro; Sumida, Paulo Y. G.; Bernardino, Angelo F.; Pereira, Olivia S.; Kanehara, Toshiyuki; Nagano, Yuriko; Nakayama, Cristina R.; Nobrega, Marcos; Pellizari, Vivian H.; Shigeno, Shuichi; Yoshida, Takao; Zhang, Jing; Kitazato, Hiroshi

2017-12-01

The discovery and description of cold seeps with deep-sea chemosynthetic communities in the Southwest Atlantic Ocean are still incomplete, despite the large proven oil and gas reserves off the coast of Brazil. In the southeastern Brazilian continental margin, where over 71% of the country's oil and gas production takes place, there are previous geological and qualitative biological evidence of seep biota associated with pockmarks on the upper slope of the Santos Basin. In order to further study seep ecosystems on the Brazilian margin, a deep-sea investigation named Iatá-Piúna cruise was conducted using the human-occupied vehicle Shinkai 6500 off Brazil's southeast continental margin. Asphalt seeps were discovered on the seafloor of the North São Paulo Plateau from depths of 2652-2752 m, representing only the third discovery of this type of seep worldwide, following those in the Gulf of Mexico and off Angola. Video and isotopic analyses indicated a number of megabenthic animals in the asphalt seeps in the North São Paulo Plateau and revealed typical deep-sea heterotrophic and photosynthesis-based fauna occupying hard substrates provided by the asphalt seep. There was no evidence of chemosynthesis-based megabenthic fauna such as vesicomyid clams, Bathymodiolus mussels, and siboglinid tube worms, or any sediment bacterial mats, gas seepage, and carbonate rock in/around the seeps. The benthic fauna was composed mainly of sponges (ca. 15 species), such as the hexactinellids Caulophacus sp., Poliopogon amadou, Saccocalyx pedunculatus, Farrea occa and cf. Chonelasma choanoides; besides typical deep-sea isidid octocorals, brisingid starfishes and galatheid crabs. The δ13C values of poriferan sponges suggested a heterotrophic and pelagic nutrition. Geochemical analyses of asphalt revealed a heavy biodegradation of hydrocarbon molecules, supported by the depletion of light n-alkanes and other labile compounds. This advanced asphalt biodegradation is the likely reason

Exploration and Discovery of Hydrocarbon Seeps, Coral Ecosystems, and Shipwrecks in the Deep Gulf of Mexico

Science.gov (United States)

Shank, T. M.; Hsing, P.; Carney, R. S.; Herrera, S.; Heyl, T.; Munro, C.; Bors, E.; Kiene, W.; Vecchione, M.; Evans, A.; Irion, J.; Warren, D.; Malik, M.; Lobecker, M.; Potter, J.

2012-12-01

Between March 20 and April 6, 2012, the NOAA Ship Okeanos Explorer served as a platform for ship-board and shore-side scientists to explore the deep Gulf of Mexico, targeting the northern West Florida Escarpment, DeSoto Canyon, the vicinity (within 11km) of the Deepwater Horizon (DWH) well, and deepwater shipwrecks. We systematically explored and discovered natural hydrocarbon seeps, diverse coral ecosystems, wooden and iron-hulled shipwrecks more than 100 years old colonized by coral communities, and sperm whale habitat between 600 and 1200m. A total of sixteen dives took advantage of new and recent maps to explore and groundtruth both hard and soft-bottom habitats, from cretaceous carbonates to mounds of coral rubble. The final ROV dive successfully groundtruthed expected methane-release areas imaged by the ship's mapping systems up to 1150m above the seafloor. The source of the mapping imagery was a stream of bubbles issuing from beneath thriving seep mussel communities. We visited five sites in the Mississippi Canyon (MC) area (lease blocks MC294, MC297, MC388, MC255, and MC036; the DWH incident took place in MC252). These sites were 11.3 km SW, 6.8 km SW, 7.6 km SW, 25.7 km E, and 27.4 km to the NE of the DWH, respectively. We used high-definition imaging systems on the Little Hercules ROV and Seirios camera platform to document more than 130 coral colonies and over 400 associated individual animals to continue to assessing the impact of the Deepwater Horizon oil spill. All of these efforts were conducted to provide fundamental knowledge of unknown and poorly known regions, ecosystems, and items of historical significance in the deep Gulf of Mexico.

Geochemical Study of Natural Bitumen, Condensate and Gas Seeps from Sousse Area, Central Tunisia

OpenAIRE

A. Belhaj Mohamed; M. Saidi; N. Boucherb; N. Ourtani; A. Soltani; I. Bouazizi; M. Ben Jrad

2015-01-01

Natural hydrocarbon seepage has helped petroleum exploration as a direct indicator of gas and/or oil subsurface accumulations. Surface macro-seeps are generally an indication of a fault in an active Petroleum Seepage System belonging to a Total Petroleum System. This paper describes a case study in which multiple analytical techniques were used to identify and characterize trace petroleum-related hydrocarbons and other volatile organic compounds in groundwater samples col...

Transience and persistence of natural hydrocarbon seepage in Mississippi Canyon, Gulf of Mexico

Science.gov (United States)

Garcia-Pineda, Oscar; MacDonald, Ian; Silva, Mauricio; Shedd, William; Daneshgar Asl, Samira; Schumaker, Bonny

2016-07-01

Analysis of the magnitude of oil discharged from natural hydrocarbon seeps can improve understanding of the carbon cycle and the Gulf of Mexico (GOM) ecosystem. With use of a large archive of remote sensing data, in combination with geophysical and multibeam data, we identified, mapped, and characterized natural hydrocarbon seeps in the Macondo prospect region near the wreck site of the drill-rig Deepwater Horizon (DWH). Satellite image processing and the cluster analysis revealed locations of previously undetected seep zones. Including duplicate detections, a total of 562 individual gas plumes were also observed in multibeam surveys. In total, SAR imagery confirmed 52 oil-producing seep zones in the study area. In almost all cases gas plumes were associated with oil-producing seep zones. The cluster of seeps in the vicinity of lease block MC302 appeared to host the most persistent and prolific oil vents. Oil slicks and gas plumes observed over the DWH site were consistent with discharges of residual oil from the wreckage. In contrast with highly persistent oil seeps observed in the Green Canyon and Garden Banks lease areas, the seeps in the vicinity of Macondo Prospect were intermittent. The difference in the number of seeps and the quantity of surface oil detected in Green Canyon was almost two orders of magnitude greater than in Mississippi Canyon.

Cold-seep carbonates of the middle and lower continental slope, northern Gulf of Mexico

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Roberts, Harry H.; Feng, Dong; Joye, Samantha B.

2010-11-01

Authigenic carbonates from cold seeps on the middle and lower continental slope of the northern Gulf of Mexico (GOM) exhibit a wide range of mineralogical and stable isotopic compositions. These carbonates consist of concretions and nodules in surface sediments, hardgrounds of crusts and isolated slabs, and mounded buildups of blocks and slabs of up to over 10 meters in relief above the surrounding seafloor. Mineralogically, the carbonates are dominated by high-Mg calcite (HMC) and aragonite. However, low levels (oil, seawater CO2, and 13C-enriched residual CO2 from methanogenesis. A similarly large variability in δ18O values (2.5 to 6.7‰ PDB) demonstrates the geochemical complexity of the slope, with some samples pointing toward an 18O-enriched oxygen source that is possibly related to advection of 18O-enriched formation water and/or to the decomposition of gas hydrate. A considerable range of mineralogical and isotopic variations in cold-seep carbonate composition was noted even within individual study sites. However, common trends occur across multiple geographic areas. This situation suggests that local controls on fluid and gas flux, types of seep hydrocarbons, the presence or absence of gas hydrate in the near-surface sediment, and chemosynthetic communities, as well as the temporal evolution of the local hydrocarbon reservoir, all may play a part in determining carbonate mineralogy and isotope geochemistry. The carbon isotope data clearly indicate that between-site variation is greater than within-site variation. Seep carbonates formed on the middle and lower continental slope of the GOM do not appear to be substantially different from those found on the upper slope (<1000-m water depth). The highly variable fluids and gases that leave their geochemical imprints on seep carbonate of the middle and lower continental slope are similar to their outer shelf and upper slope counterparts.

Historical polycyclic aromatic and petrogenic hydrocarbon loading in Northern Central Gulf of Mexico shelf sediments.

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Overton, E B; Ashton, B M; Miles, M S

2004-10-01

The distribution of selected hydrocarbons within ten dated sediment cores taken from the Mississippi River Bight off coastal Louisiana suggests a chronic contaminant loading from several sources including the river itself, oil and gas exploration in the central Gulf of Mexico (GOM) shelf area, and natural geologic hydrocarbon seeps. Data were grouped as either total polycyclic aromatic hydrocarbons (PAH's), which were indicative of pyrogenic PAH's; or estimated total hopanes (indicative of petrogenic hydrocarbons). The total PAH concentrations and estimated total hopanes begin increasing above background levels (approximately 200 ng g(-1)) after the 1950s. The distribution of these hydrocarbons and hopanes within the dated sediment cores suggests that the Mississippi River is a regional source of pyrogenic PAH's, and that the hopanes are from natural geologic hydrocarbon seeps, oil and gas exploration in the GOM, or both.

Occurrence of faecal pellet-filled simple and composite burrows in cold seep carbonates: A glimpse of a complex benthic ecosystem

Digital Repository Service at National Institute of Oceanography (India)

Mazumdar, A.; Joshi, R.K.; Peketi, A.; Kocherla, M.

of inorganic sulphur in sediments and shales. Chemical Geology 54, 149–155. Cordes, E. E., Carney, S. L., Hourdez, S., Carney, R. S., Brooks, J. M. & Fisher, C. R. 2007. Cold seeps of the deep Gulf of Mexico: Community structure and biogeographic comparisons..., Surficial hydrocarbon seep infauna from the Blake Ridge (Atlantic Ocean, 2150 m) and the Gulf of Mexico (690– 2240 m) PSZN. Marine Ecology 25, 313–336. Sahling, H., Rickert, D., Lee, R.W., Linke, P., Suess, E., 2002, Macrofaunal community structure...

Cold seep epifaunal communities on the Hikurangi margin, New Zealand: composition, succession, and vulnerability to human activities.

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David A Bowden

Full Text Available Cold seep communities with distinctive chemoautotrophic fauna occur where hydrocarbon-rich fluids escape from the seabed. We describe community composition, population densities, spatial extent, and within-region variability of epifaunal communities at methane-rich cold seep sites on the Hikurangi Margin, New Zealand. Using data from towed camera transects, we match observations to information about the probable life-history characteristics of the principal fauna to develop a hypothetical succession sequence for the Hikurangi seep communities, from the onset of fluid flux to senescence. New Zealand seep communities exhibit taxa characteristic of seeps in other regions, including predominance of large siboglinid tubeworms, vesicomyid clams, and bathymodiolin mussels. Some aspects appear to be novel; however, particularly the association of dense populations of ampharetid polychaetes with high-sulphide, high-methane flux, soft-sediment microhabitats. The common occurrence of these ampharetids suggests they play a role in conditioning sulphide-rich sediments at the sediment-water interface, thus facilitating settlement of clam and tubeworm taxa which dominate space during later successional stages. The seep sites are subject to disturbance from bottom trawling at present and potentially from gas hydrate extraction in future. The likely life-history characteristics of the dominant megafauna suggest that while ampharetids, clams, and mussels exploit ephemeral resources through rapid growth and reproduction, lamellibrachid tubeworm populations may persist potentially for centuries. The potential consequences of gas hydrate extraction cannot be fully assessed until extraction methods and target localities are defined but any long-term modification of fluid flow to seep sites would have consequences for all chemoautotrophic fauna.

Physical and geochemical drivers of CDOM variability near a natural seep site in the Gulf of Mexico

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Edwards, C. R.; Powers, L.; Medeiros, P. M.

2016-02-01

Colored dissolved organic matter (CDOM) on the continental shelf and slope can serve as a marker for fresh water influence, indicate the presence of hydrocarbons, and provide important clues about nutrient content and organic matter cycling. Autonomous underwater vehicles such as gliders allow for subsurface measurement of CDOM fluorescence for weeks to months; these time series may be especially valuable in the northern Gulf of Mexico, where CDOM inputs of both terrestrial and oil and gas sources can be significant. Data from a recent glider deployment near a natural seep site (GC600) on the continental slope over 180km from shore suggest simultaneous influence of Mississippi plume water and hydrocarbon inputs in the upper 200m, with variability in fluorescence at a range of vertical and temporal scales. We will explore patterns in spatial and temporal variability of glider-measured hydrography, dissolved oxygen, and bio-optical data (CDOM, chlorophyll-a, backscatter fluorescence), and use their combination to infer a terrigenous and/or fossil fuel source(s). Taking advantage of a combination of satellite sea surface temperature, ocean color, wind, and data from moored and mobile platforms, we will examine physical controls on transport and vertical mixing of CDOM and the potential role of nonlinear mesoscale eddies, which can trap water in their interior and may transport river- or hydrocarbon-derived CDOM over long distances. The combined data set will be used to consider and potentially constrain the effect of photodegradation and other biogeochemical causes for CDOM fluorescence variability in the upper 200m.

Escarpment seeps at Shiprock, New Mexico

International Nuclear Information System (INIS)

1991-10-01

The purpose of this report is to characterize the seeps identified at the Shiprock UMTRA Project site during the prelicensing custodial care inspection conducted in December of 1990, to evaluate the relationship between the seeps and uranium processing activities or tailings disposal, and to evaluate the risk posed by the seep water to human health and the environment. The report provides a brief description of the geology, groundwater hydrology, and surface water hydrology. The locations of the seeps and monitor wells are identified, and the water quality of the seeps and groundwater is discussed in the context of past activities at the site. The water quality records for the site are presented in tables and appendices; this information was used in the risk assessment of seep water

Mercury concentrations, speciation, and isotopic composition in sediment from a cold seep in the northern Gulf of Mexico

International Nuclear Information System (INIS)

Brown, Garry; Sleeper, Kenneth; Johnson, Marcus W.; Blum, Joel D.; Cizdziel, James V.

2013-01-01

Highlights: • T-Hg, MMHg, and Hg isotopes were determined in Gulf of Mexico deep marine sediments. • Levels of mass independent fractionation of Hg isotopes varied from coastal sediments. • Levels of the MMHg were only slightly elevated at the cold seep site. • Cold seeps do not appear to be significant sources of MMHg to Gulf of Mexico waters. -- Abstract: Total-Hg, monomethylmercury (MMHg), and mercury isotopic composition was determined in sediment from a cold seep and background sites in the northern Gulf of Mexico (nGoM). Total-Hg averaged 50 ng/g (n = 28), ranged from 31 to 67 ng/g, and decreased with depth (0–15 cm). MMHg averaged 0.91 ng/g (n = 18), and ranged from 0.2 to 1.9 ng/g. There was no significant difference for total-Hg or MMHg between cold seep and background sites. δ 202 Hg ranged from −0.5 to −0.8‰ and becomes more negative with depth (r = 0.989). Mass independent fractionation (Δ 199 Hg) was small but consistently positive (0.04–0.12‰); there was no difference between cold seeps (Δ 199 Hg = +0.09 ± 0.03; n = 7, 1SD) and background sites (Δ 199 Hg = +0.07 ± 0.02; n = 5, 1SD). This suggests that releases of hydrocarbons at the cold seep do not significantly alter Hg levels, and that cold seeps are likely not major sources of MMHg to nGoM waters

Natural hydrocarbon seeps observation with underwater gliders and UV fluorescence sensor

Science.gov (United States)

Rochet, V.

2016-02-01

Hydrocarbons may leak to the near-surface from subsurface accumulations, from mature source rock, or by buoyancy along major cross-strata routes. The presence of migrating near-surface hydrocarbons can provide strong evidence for the presence of a working petroleum system, as well as valuable information on source, maturity, and migration pathways. Detection and characterization of hydrocarbons in the water column may then help to de-risk hydrocarbon plays at a very preliminary stage of an exploration program. In order to detect hydrocarbons in the water column, an underwater glider survey was conducted in an offshore frontier area. Driven by buoyancy variation, underwater gliders enable collecting data autonomously along the water column for weeks to months. Underwater gliders are regularly piloted from shore by satellite telemetry and do not require a surface supervising vessel resulting in substantial operational costs savings. The data compiled, over 700m depth of the water column, included temperature, salinity, pressure, dissolved oxygen and hydrocarbon components (phenanthrene and naphthalene) measured by "MINIFLUO" sensors to particularly target representative crude oil compounds Two gliders were deployed at sea, one from coast in shallow water and the other one offshore on the survey area. Both accurately squared the survey area following pre-defined lines and cross lines. Data files were transmitted by satellite telemetry in near real time during the performance of the mission for real time observations and appropriate re-positioning of the gliders. Using rechargeable underwater gliders increased reliability reducing the risk of leakage and associated logistics during operation at sea. Despite strong evidences of seabed seepages such as pockmarks, faults, etc, over the area of interest, no hydrocarbon indices were detected in the water column, which was confirmed later by seabed sample analysis. The use of glider platforms for hydrocarbon detection has

Low-maturity Kulthieth Formation coal: A possible source of polycyclic aromatic hydrocarbons in benthic sediment of the northern Gulf of Alaska

Science.gov (United States)

Van Kooten, G. K.; Short, J.W.; Kolak, J.J.

2002-01-01

The successful application of forensic geology to contamination studies involving natural systems requires identification of appropriate endmembers and an understanding of the geologic setting and processes affecting the systems. Studies attempting to delineate the background, or natural, source for hydrocarbon contamination in Gulf of Alaska (GOA) benthic sediments have invoked a number of potential sources, including seep oils, source rocks, and coal. Oil seeps have subsequently been questioned as significant sources of hydrocarbons present in benthic sediments of the GOA in part because the pattern of relative polycyclic aromatic hydrocarbon (PAH) abundance characteristic of benthic GOA sediments is inconsistent with patterns typical of weathered seep oils. Likewise, native coal has been dismissed in part because ratios of labile hydrocarbons to total organic carbon (e.g. PAH:TOC) for Bering River coal field (BRCF) sources are too low - i.e. the coals are over mature - to be consistent with GOA sediments. We present evidence here that native coal may have been prematurely dismissed, because BRCF coals do not adequately represent the geochemical signatures of coals elsewhere in the Kulthieth Formation. Contrary to previous thought, Kulthieth Formation coals east of the BRCF have much higher PAH: TOC ratios, and the patterns of labile hydrocarbons in these low thermal maturity coals suggest a possible genetic relationship between Kulthieth Formation coals and nearby oil seeps on the Sullivan anticline. Analyses of low-maturity Kulthieth Formation coal indicate the low maturity coal is a significant source of PAH. Source apportionment models that neglect this source will underestimate the contribution of native coals to the regional background hydrocarbon signature. ?? Published by Elsevier Science Ltd. on behalf of AEHS.

Short-chain alkane cycling in deep Gulf of Mexico cold-seep sediments

Science.gov (United States)

Sibert, R.; Joye, S. B.; Hunter, K.

2015-12-01

Mixtures of light hydrocarbon gases are common in deep Gulf of Mexico cold-seep sediments, and are typically dissolved in pore fluids, adsorbed to sediment particles, trapped in methane ice, or as free gas. The dominant component in these natural gas mixtures is usually methane (>80% C1), but ethane (C2) and propane (C3) are nearly always present in trace amounts (95% of the methane produced at depth never reaches the water column. Production of C1 and C2 in deep-sea sediments has been historically attributed only to thermocatalytic processes, though limited data suggests production of C2/C3 compounds through the activity of archaea at depth. Furthermore, carbon isotopic data on ethane and propane from deep cores of Gulf of Mexico sediments suggest alkanogenesis at >3 m depth in the sediment column and alkane oxidation in uppermost oxidant-rich sediments. Additional studies have also isolated microorganisms capable of oxidizing ethane and propane in the laboratory, but field studies of microbial-driven dynamics of C2/C3 gases in cold-seep sediments are rare. Here, we present the results of a series of incubation experiments using sediment slurries culled from surface sediments from one of the most prolific natural oil and gas seeps in the Gulf of Mexico. Rates of alkane oxidation were measured under a variety of conditions to assess the surface-driven microbial controls on C2/C3 cycling in cold-seep environments. Such microbial processes are important in terms of the possible 'oxidative overprinting' of alkane isotopic signatures produced at depth, possibly obscuring typical microbial isotopic signals.

Anaerobic oxidation of methane at a marine methane seep in a forearc sediment basin off Sumatra, Indian Ocean

Directory of Open Access Journals (Sweden)

Michael eSiegert

2011-12-01

Full Text Available A cold methane-seep was discovered in a forearc sediment basin off the island Sumatra, exhibiting a methane-seep adapted microbial community. A defined seep centre of activity, like in mud volcanoes, was not discovered. The seep area was rather characterized by a patchy distribution of active spots. The relevance of AOM was reflected by 13C depleted isotopic signatures of dissolved inorganic carbon (DIC. The anaerobic conversion of methane to CO2 was confirmed in a 13C-labelling experiment. Methane fuelled a vital microbial and invertebrate community which was reflected in cell numbers of up to 4 x 109 cells cm 3 sediment and 13C depleted guts of crabs populating the seep area. The microbial community was analysed by total cell counting, catalyzed reporter deposition – fluorescence in situ hybridisation (CARD-FISH, quantitative real-time PCR (qPCR and denaturing gradient gel electrophoresis (DGGE. CARD-FISH cell counts and qPCR measurements showed the presence of Bacteria and Archaea, but only small numbers of Eukarya. The archaeal community comprised largely members of ANME-1 and ANME-2. Furthermore, members of the Crenarchaeota were frequently detected in the DGGE analysis. Three major bacterial phylogenetic groups (δ-Proteobacteria, candidate division OP9 and Anaerolineaceae were abundant across the study area. Several of these sequences were closely related to the genus Desulfococcus of the family Desulfobacteraceae, which is in good agreement with previously described AOM sites. In conclusion, the majority of the microbial community at the seep consisted of AOM related microorganisms, while the relevance of higher hydrocarbons as microbial substrates was negligible.

Low-maturity Kulthieth Formation coal : a possible source of polycyclic aromatic hydrocarbons in benthic sediment of the Northern Gulf of Alaska

International Nuclear Information System (INIS)

Van Kooten, G.K.; Short, J.W.; Kolak, J.J.

2002-01-01

This study addressed the issue of sources of hydrocarbons for benthic sediments in the Gulf of Alaska (GOA) with particular reference to the application of forensic geology to identify end members and to explain the geologic setting and processes affecting the system. Native coals and natural seep oils have been questioned in the past decade as possible sources of background hydrocarbons because the pattern of relative polycyclic aromatic hydrocarbon (PAH) abundance characteristic of benthic GOA sediments is inconsistent with patterns typical of weathered seep oils. Native coal has also been dismissed as a pollution source because ratios of labile hydrocarbons to total organic carbon for Bering River coal field (BRCF) sources are too low to be consistent with GOA sediments. The authors present evidence that perhaps native coal has been prematurely dismissed as a pollution source because BRCF coals do not represent adequately the geochemical signatures of coals elsewhere in the Kulthieth Formation which have much higher PAH:TOC ratios. The patterns of labile hydrocarbons in these low thermal maturity coals indicate a genetic relationship between Kulthieth Formation coals and nearby oil seeps on the Sullivan anticline. Analysis of the coal suggests it is a significant source of PAH, and it was cautioned that source models that do not include this source will underestimate the contribution of native coals to the background hydrocarbon signature in the Gulf of Alaska. 32 refs., 2 tabs., 8 figs

Fungal diversity in deep-sea sediments associated with asphalt seeps at the Sao Paulo Plateau

Science.gov (United States)

Nagano, Yuriko; Miura, Toshiko; Nishi, Shinro; Lima, Andre O.; Nakayama, Cristina; Pellizari, Vivian H.; Fujikura, Katsunori

2017-12-01

We investigated the fungal diversity in a total of 20 deep-sea sediment samples (of which 14 samples were associated with natural asphalt seeps and 6 samples were not associated) collected from two different sites at the Sao Paulo Plateau off Brazil by Ion Torrent PGM targeting ITS region of ribosomal RNA. Our results suggest that diverse fungi (113 operational taxonomic units (OTUs) based on clustering at 97% sequence similarity assigned into 9 classes and 31 genus) are present in deep-sea sediment samples collected at the Sao Paulo Plateau, dominated by Ascomycota (74.3%), followed by Basidiomycota (11.5%), unidentified fungi (7.1%), and sequences with no affiliation to any organisms in the public database (7.1%). However, it was revealed that only three species, namely Penicillium sp., Cadophora malorum and Rhodosporidium diobovatum, were dominant, with the majority of OTUs remaining a minor community. Unexpectedly, there was no significant difference in major fungal community structure between the asphalt seep and non-asphalt seep sites, despite the presence of mass hydrocarbon deposits and the high amount of macro organisms surrounding the asphalt seeps. However, there were some differences in the minor fungal communities, with possible asphalt degrading fungi present specifically in the asphalt seep sites. In contrast, some differences were found between the two different sampling sites. Classification of OTUs revealed that only 47 (41.6%) fungal OTUs exhibited >97% sequence similarity, in comparison with pre-existing ITS sequences in public databases, indicating that a majority of deep-sea inhabiting fungal taxa still remain undescribed. Although our knowledge on fungi and their role in deep-sea environments is still limited and scarce, this study increases our understanding of fungal diversity and community structure in deep-sea environments.

Marine cold seeps and their manifestations: geological control, biogeochemical criteria and environmental conditions

Science.gov (United States)

Suess, Erwin

2014-10-01

Characteristics of cold seeps at different geologic settings are the subject of this review primarily based on results of the Research Consortium SFB 574. Criteria are drawn from examples on the erosive convergent margin off Costa Rica, the accretionary margin off Chile supplemented by examples from the transform margin of the Golf of Cadiz and the convergent Hikurangi margin off New Zealand. Others are from well-studied passive margins of the Black Sea, the Golf of Mexico, the eastern Mediterranean Sea and the South China Sea. Seeps at all settings transport water and dissolved compounds to the ocean through the seafloor by different forcing mechanism and from different depths of the submerged geosphere (10s of meters to 10s of km). The compounds sustain oasis-type ecosystems by providing bioactive reductants sulfide, methane and hydrogen. Hereby, the interaction between fluid composition, flux rates and biota results in a diagnostic hydrocarbon-metazoan-microbe-carbonate association; currently, well over 100 active sites are known. The single most important reaction is microbially mediated anaerobic oxidation of methane with secondary reactions involving S-biogeochemistry and carbonate mineral precipitation. Seep fluids and their seafloor manifestations provide clues as to source depth, fluid-sediment/rock interaction during ascent, lifetime and cyclicity of seepage events but less so on the magnitude of return flow. At erosive margins, Cl-depleted and B-enriched fluids from clay dehydration provide criteria for source depth and temperature. The upward material flow generates mud volcanoes at the seafloor above the projected location of dehydration at depth. At accretionary margins, fluids are derived from more shallow depths by compaction of sediments as they ride on the incoming oceanic plate; they are emitted through thrust faults. At highly sedimented margins, organic-rich and evaporite-containing strata (when present) determine the final fluid composition

Significance of Microbiology in Porous Hydrocarbon Related Systems

KAUST Repository

Augsburger, Nicolas

2017-07-01

This thesis explores bio-mediated processes in geotechnical and petroleum engineering. Worldwide energy consumption is rapidly increasing as the world population and per-capita consumption rises. The US Energy Information Agency (EIA) predicts that hydrocarbons will remain the primary energy source to satisfy the surging energy demands in the near future. The three topics described in detail in this document aim to link microbiology with geotechnical engineering and the petroleum industry. Microorganisms have the potential to exploit residual hydrocarbons in depleted reservoirs in a technique known as microbial enhanced oil recovery, MEOR. The potential of biosurfactants was analyzed in detail with a literature review. Biosurfactant production is the most accepted MEOR technique, and has been successfully implemented in over 700 field cases. Temperature is the main limiting factor for these techniques. The dissolution of carbonates by microorganisms was investigated experimentally. We designed a simple, economical, and robust procedure to monitor diffusion through porous media. This technique determined the diffusion coefficient of H+ in 1.5% agar, 1.122 x 10-5 cm2 sec-1, by using bromothymol blue as a pH indicator and image processing. This robust technique allows for manipulation of the composition of the agar to identify the effect of specific compounds on diffusion. The Red Sea consists of multiple seeps; the nearby sediments are telltales of deeper hydrocarbon systems. Microbial communities associated with the sediments function as in-situ sensors that provide information about the presence of carbon sources, metabolites, and the remediation potential. Sediments seeps in the Red Sea revealed different levels of bioactivity. The more active seeps, from the southern site in the Red Sea, indicated larger pore sizes, higher levels of carbon, and bioactivity with both bacteria and archaeal species present.

Satellite SAR inventory of Gulf of Mexico oil seeps and shallow gas hydrates

Science.gov (United States)

Garcia, O.; MacDonald, I. R.; Zimmer, B.; Shedd, W.; Frye, M.

2009-04-01

Satellite synthetic aperture radar (SAR) images from the RADARSAT platform were used to detect and inventory persistent layers of oil released from natural seeps in the Gulf of Mexico. Previously published inventories of natural oil seeps in the Gulf have been limited in scope and have relied on manual interpretation of satellite images (Mitchell et al. 1999; De Beukelaer et al. 2003). We developed a texture classifying neural network algorithm (TCNNA) to rapidly identify floating oil-layers in a semi-supervised operation. Oil layers, known as slicks, were recognized as long (10 km), narrow (100 m), often curvilinear streaks with distinct points of origin where oil reaches the ocean surface. After training the TCNNA over known seep areas and under a range of environmental and viewing conditions, the procedure was applied to 426 separate images that covered ocean areas of 100x100 km (Standard Beam Mode), 102 images that covered ocean areas of 450x450 km(ScanSAR Wide Beam Mode), and 84 images that covered ocean areas of 300x300 km (ScanSAR Narrow Beam Mode). This image data-set was collected between 1994 and 2007. It covered the entire Gulf of Mexico with a repeat rate of 4 to109, with the highest concentration over the continental slope. This effort identified a total of 4957 slicks among all the images. Of these, 287 appeared a single time in isolated locations and may therefore be false targets. The remaining slicks appeared in groups of up to 9 separate features, clustered in areas of 1 to 6.5 km across. When slicks appear within the same area in repeated images, they are judged to have a persistent source—a bubbling vent on the seafloor (MacDonald et al. 2002). Persistent sources represent geologic formations defined by migrating hydrocarbons that may include multiple separate vents. A total of 559 formations were defined by repeated imaging; these comprised a maximum of 1995 and a minimum of 1263 individual vents. This total was distributed between U

Cenozoic Methane-Seep Faunas of the Caribbean Region.

Directory of Open Access Journals (Sweden)

Steffen Kiel

Full Text Available We report new examples of Cenozoic cold-seep communities from Colombia, Cuba, the Dominican Republic, Trinidad, and Venezuela, and attempt to improve the stratigraphic dating of Cenozoic Caribbean seep communities using strontium isotope stratigraphy. Two seep faunas are distinguished in Barbados: the late Eocene mudstone-hosted 'Joes River fauna' consists mainly of large lucinid bivalves and tall abyssochrysoid gastropods, and the early Miocene carbonate-hosted 'Bath Cliffs fauna' containing the vesicomyid Pleurophopsis, the mytilid Bathymodiolus and small gastropods. Two new Oligocene seep communities from the Sinú River basin in Colombia consist of lucinid bivalves including Elongatolucina, thyasirid and solemyid bivalves, and Pleurophopsis. A new early Miocene seep community from Cuba includes Pleurophopsis and the large lucinid Meganodontia. Strontium isotope stratigraphy suggests an Eocene age for the Cuban Elmira asphalt mine seep community, making it the oldest in the Caribbean region. A new basal Pliocene seep fauna from the Dominican Republic is characterized by the large lucinid Anodontia (Pegophysema. In Trinidad we distinguish two types of seep faunas: the mudstone-hosted Godineau River fauna consisting mainly of lucinid bivalves, and the limestone-hosted Freeman's Bay fauna consisting chiefly of Pleurophopsis, Bathymodiolus, and small gastropods; they are all dated as late Miocene. Four new seep communities of Oligocene to Miocene age are reported from Venezuela. They consist mainly of large globular lucinid bivalves including Meganodontia, and moderately sized vesicomyid bivalves. After the late Miocene many large and typical 'Cenozoic' lucinid genera disappeared from the Caribbean seeps and are today known only from the central Indo-Pacific Ocean. We speculate that the increasingly oligotrophic conditions in the Caribbean Sea after the closure of the Isthmus of Panama in the Pliocene may have been unfavorable for such large

Aliphatic hydrocarbon and polycyclic aromatic hydrocarbon geochemistry of twelve major rivers in the Northwest Territories

International Nuclear Information System (INIS)

Backus, S.; Swyripa, M.; Peddle, J.; Jeffries, D.S.

1995-01-01

Suspended sediment and water samples collected from twelve major rivers in the Northwest Territories were analyzed for aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) to assess the sources and transport of hydrocarbons entering the Arctic Ocean. Three stations on the Mackenzie River and one station near the mouth of eleven other northern rivers were selected for sampling. Samples were collected on the Mackenzie River on four occasions to characterize spring, summer and fall flow conditions and once on the remaining eleven rivers during high flow conditions. The Mackenzie River is distinctively different then the other eleven rivers. Naturally occurring hydrocarbons predominate in the river. These hydrocarbons include biogenic alkanes, diagenic PAHs, petrogenic alkanes, and PAHs from oil seeps and/or bitumens. Anthropogenic inputs of PAHs are low as indicated by low concentrations of combustion PAHs. Alkyl PAH distributions indicate that a significant component of the lower molecular weight PAH fraction is petrogenic. The majority of the high molecular weight PAHs, together with the petrogenic PAHs have a principal source in the Mackenzie River

Potential sources of hydrocarbons and their microbial degradation in sediments from the deep geothermal Lusi site, Indonesia

Science.gov (United States)

Krueger, Martin; Mazzini, Adriano; Scheeder, Georg; Blumenberg, Martin

2017-04-01

The Lusi eruption represents one of the largest ongoing sedimentary hosted geothermal systems, which started in 2006 following an earthquake on Java Island. Since then it has been continuously producing hot and hydrocarbon rich mud from a central crater with peaks reaching 180.000 m3 per day. Numerous investigations focused on the study of microbial communities which thrive at offshore methane and oil seeps and mud volcanoes, however very little has been done on onshore seeping structures. Lusi represents a unique opportunity to complete a comprehensive study of onshore microbial communities fed by the seepage of CH4 as well as of liquid hydrocarbons originating from one or more km below the surface. While the source of the methane at Lusi is unambiuous, the origin of the seeping oil is still discussed. Both, source and maturity estimates from biomarkers, are in favor of a type II/III organic matter source. Likely the oils were formed from the studied black shales (deeper Ngimbang Fm.) which contained a Type III component in the Type II predominated organic matter. In all samples large numbers of active microorganisms were present. Rates for aerobic methane oxidation were high, as was the potential of the microbial communities to degrade different hydrocarbons. The data suggests a transition of microbial populations from an anaerobic, hydrocarbon-driven metabolism in fresher samples from center or from small seeps to more generalistic, aerobic microbial communities in older, more consolidated sediments. Ongoing microbial activity in crater sediment samples under high temperatures (80-95C) indicate a deep origin of the involved microorganisms. First results of molecular analyses of the microbial community compositions confirm the above findings. This study represents an initial step to better understand onshore seepage systems and provides an ideal analogue for comparison with the better investigated offshore structures.

Anaerobic Oxidation of Methane at a Marine Methane Seep in a Forearc Sediment Basin off Sumatra, Indian Ocean.

Science.gov (United States)

Siegert, Michael; Krüger, Martin; Teichert, Barbara; Wiedicke, Michael; Schippers, Axel

2011-01-01

A cold methane seep was discovered in a forearc sediment basin off the island Sumatra, exhibiting a methane-seep adapted microbial community. A defined seep center of activity, like in mud volcanoes, was not discovered. The seep area was rather characterized by a patchy distribution of active spots. The relevance of anaerobic oxidation of methane (AOM) was reflected by (13)C-depleted isotopic signatures of dissolved inorganic carbon. The anaerobic conversion of methane to CO(2) was confirmed in a (13)C-labeling experiment. Methane fueled a vital microbial community with cell numbers of up to 4 × 10(9) cells cm(-3) sediment. The microbial community was analyzed by total cell counting, catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH), quantitative real-time PCR (qPCR), and denaturing gradient gel electrophoresis (DGGE). CARD-FISH cell counts and qPCR measurements showed the presence of Bacteria and Archaea, but only small numbers of Eukarya. The archaeal community comprised largely members of ANME-1 and ANME-2. Furthermore, members of the Crenarchaeota were frequently detected in the DGGE analysis. Three major bacterial phylogenetic groups (δ-Proteobacteria, candidate division OP9, and Anaerolineaceae) were abundant across the study area. Several of these sequences were closely related to the genus Desulfococcus of the family Desulfobacteraceae, which is in good agreement with previously described AOM sites. In conclusion, the majority of the microbial community at the seep consisted of AOM-related microorganisms, while the relevance of higher hydrocarbons as microbial substrates was negligible.

Bioaccumulation of petroleum hydrocarbons in arctic amphipods in the oil development area of the Alaskan Beaufort Sea.

Science.gov (United States)

Neff, Jerry M; Durell, Gregory S

2012-04-01

An objective of a multiyear monitoring program, sponsored by the US Department of the Interior, Bureau of Ocean Energy Management was to examine temporal and spatial changes in chemical and biological characteristics of the Arctic marine environment resulting from offshore oil exploration and development activities in the development area of the Alaskan Beaufort Sea. To determine if petroleum hydrocarbons from offshore oil operations are entering the Beaufort Sea food web, we measured concentrations of hydrocarbons in tissues of amphipods, Anonyx nugax, sediments, Northstar crude oil, and coastal peat, collected between 1999 and 2006 throughout the development area. Mean concentrations of polycyclic aromatic hydrocarbons (PAH), saturated hydrocarbons (SHC), and sterane and triterpane petroleum biomarkers (StTr) were not significantly different in amphipods near the Northstar oil production facility, before and after it came on line in 2001, and in amphipods from elsewhere in the study area. Forensic analysis of the profiles (relative composition and concentrations) of the 3 hydrocarbon classes revealed that hydrocarbon compositions were different in amphipods, surface sediments where the amphipods were collected, Northstar crude oil, and peat from the deltas of 4 North Slope rivers. Amphipods and sediments contained a mixture of petrogenic, pyrogenic, and biogenic PAH. The SHC in amphipods were dominated by pristane derived from zooplankton, indicating that the SHC were primarily from the amphipod diet of zooplankton detritus. The petroleum biomarker StTr profiles did not resemble those in Northstar crude oil. The forensic analysis revealed that hydrocarbons in amphipod tissues were not from oil production at Northstar. Hydrocarbons in amphipod tissues were primarily from their diet and from river runoff and coastal erosion of natural diagenic and fossil terrestrial materials, including seep oils, kerogens, and peat. Offshore oil and gas exploration and development

Short- and Long-Term Dynamics of Gas Hydrate at GC600: A Gulf of Mexico Hydrocarbon Seep

Science.gov (United States)

MacDonald, I. R.; Johansen, C.; Silva, M.; Daneshgar, S.; Garcia-Pineda, O. G.; Shedd, W. W.

2014-12-01

The GC600 hydrocarbon seep is located at 1200 m in the northern Gulf of Mexico (GOM). Satellite data show it to be one of the most prolific sources of natural oil slicks in the entire GOM. We mapped its seafloor oil and gas vents with 3-D seismic, swath-bathymetry acoustics and submersible observations, documenting gas hydrate deposits, brine pools, benthic fauna, and authigenic carbonates. Geophysical profiles show subbottom locations of salt bodies and migration conduits. We deployed time-lapse imaging systems focused on individual vents to quantify release rates. Oil and gas flow upward along the flanks of an allochthonous salt body from source rocks at 10,000 m and migrate to the seafloor from faults emanating from the salt. Venting to the water column and surface consists of oily bubbles and occurs in two fields separated by ~1 km. The NW vent field (Megaplume) appears to be a more recent expression and hosts about three highly active vents; while the SE vent field (Birthday Candles) hosts more than 10 vents that are generally slower. We measured discharge rates of 2.6 cm3 s-1 and Megaplume and 0.09 cm3 s-1 at Birthday Candles. Although surface deposits of gas hydrate were evident at both vent fields, the Birthday Candles area featured dozens of conical mounds formed by gas hydrate that were dark brown due to large amounts of liquid oil perfused throughout the deposits. Large brine pools indicated gas hydrate formation at the seafloor. Venting occurred in horizontal fissures on the mounds, in which oil and hydrate combined to form short-lived chimneys and balloon-like structures. Ice worms (Hesiocaeca methanicola) were extremely abundant in burrows extending from the sediment into the gas hydrate. Proceeding farther to the SE, venting is reduced and absent, but surface carbonate deposits suggest relict gas hydrate mounds. We propose that the NW to SE trend at GC600 encompasses the progressive development of a biogeochemical filter that sequesters and

Presence of aliphatic and polycyclic aromatic hydrocarbons in near-surface sediments of an oil spill area in Bohai Sea.

Science.gov (United States)

Li, Shuanglin; Zhang, Shengyin; Dong, Heping; Zhao, Qingfang; Cao, Chunhui

2015-11-15

In order to determine the source of organic matter and the fingerprint of the oil components, 50 samples collected from the near-surface sediments of the oil spill area in Bohai Sea, China, were analyzed for grain size, total organic carbon, aliphatic hydrocarbons (AHs), and polycyclic aromatic hydrocarbons (PAHs). The concentrations of C15-35 n-alkanes and 16 United States Environmental Protection Agency (US EPA) priority pollutant PAHs were found in the ranges of 0.88-3.48μg g(-1) and 9.97-490.13ng/g, respectively. The terrestrial organic matters characterized by C27-C35 n-alkanes and PAHs, resulting from the combustion of higher plants, are dominantly contributed from the transportation of these plants by rivers. Marine organic matters produced from plankton and aquatic plants were represented by C17-C26 n-alkanes in AHs. Crude oil, characterized by C17-C21 n-alkanes, unresolved complex mixture (UCM) with a mean response factor of C19 n-alkanes, low levels of perylene, and a high InP/(InP+BghiP) ratio, seeped into the oceans from deep hydrocarbon reservoirs, as a result of geological faults. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cold-seep habitat mapping: High-resolution spatial characterization of the Blake Ridge Diapir seep field

Science.gov (United States)

Wagner, Jamie K. S.; McEntee, Molly H.; Brothers, Laura L.; German, Christopher R.; Kaiser, Carl L.; Yoerger, Dana R.; Van Dover, Cindy Lee

2013-08-01

Relationships among seep community biomass, diversity, and physiographic controls such as underlying geology are not well understood. Previous efforts to constrain these relationships at the Blake Ridge Diapir were limited to observations from piloted deep-submergence vehicles. In August 2012, the autonomous underwater vehicle (AUV) Sentry collected geophysical and photographic data over a 0.131 km2 area at the Blake Ridge Diapir seeps. A nested survey approach was used that began with a regional or reconnaissance-style survey using sub-bottom mapping systems to locate and identify seeps and underlying conduits. This survey was followed by AUV-mounted sidescan sonar and multibeam echosounder systems mapping on a mesoscale to characterize the seabed physiography. At the most detailed survey level, digital photographic imaging was used to resolve sub-meter characteristics of the biology. Four pockmarks (25-70 m diameter) were documented, each supporting chemosynthetic communities. Concentric zonation of mussels and clams suggests the influence of chemical gradients on megafaunal distribution. Data collection and analytical techniques used here yield high-resolution habitat maps that can serve as baselines to constrain temporal evolution of seafloor seeps, and to inform ecological niche modeling and resource management.

Evidence of the aryl hydrocarbon receptor in chemosynthetic mussels from the Gulf of Mexico

International Nuclear Information System (INIS)

Willett, K.; Thomsen, J.; Wilson, C.; McDonald, S.; Safe, S.

1995-01-01

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that controls expression of various genes including cytochrome P450. Polynuclear aromatic and halogenated aromatic hydrocarbons are agonists for the AhR in fish and mammalian species. Previously, a homologous AhR has not been identified in marine invertebrate species. Chemosynthetic mussels were collected from gas and petroleum seeps in the Gulf of Mexico to investigate the presence of the AhR and the induction of the cytochrome P450 system. Aryl hydrocarbon hydroxylase and glutathione S-transferase activities in the gill and hepatopancreas were elevated in the petroleum seep mussels relative to those from the gas seep. A nuclear AhR in the hepatopancreas was detected in both mussel populations after treatment with [ 3 H]-tetrachlorodibenzo-p-dioxin (tcdd) followed by sucrose density gradient analysis. Gel mobility shift assays using a labeled dioxin responsive element (DRE) oligonucleotide and tcdd-transformed mussel cytosol showed a retarded band which could be competed with excess unlabeled DRE. Results from gel shifts indicated specific binding of the tcdd-mussel AhR complex to its responsible element. Finally, PCR primers designed to amplify a 700 base pair region of the human AhR detected AhR mRNA in both mussel populations. The sequence of this PCR product is being determined. The presence of the AhR in marine invertebrates has important implications in the evolutionary age of the AhR

Presence and diversity of anammox bacteria in cold hydrocarbon-rich seeps and hydrothermal vent sediments of the Guaymas Basin

Directory of Open Access Journals (Sweden)

Lina eRuss

2013-08-01

Full Text Available Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox bacteria but this has not been investigated in detail. Here we report the diversity and abundance of anammox bacteria in sediments that seep cold hydrocarbon-rich fluids and hydrothermal vent areas of the Guaymas Basin in the Cortés Sea using the unique functional anammox marker gene, hydrazine synthase (hzsA. All clones retrieved were closely associated to the ‘Candidatus Scalindua’ genus. Phylogenetic analysis revealed two distinct clusters of hzsA sequences (Ca. Scalindua hzsA cluster I and II. Comparison of individual sequences from both clusters showed that several of these sequences had a similarity as low as 76% on nucleotide level. Based on the analysis of this phylomarker, a very high interspecies diversity within the marine anammox group is apparent. Absolute numbers of anammox bacteria in the sediments samples were determined by amplification of a 257 bp fragment of the hszA gene in a qPCR assay. The results indicate that numbers of anammox bacteria are generally higher in cold hydrocarbon-rich sediments compared to the vent areas and the reference zone. Ladderanes, lipids unique to anammox bacteria were also detected in several of the sediment samples corroborating the hzsA analysis. Due to the high concentrations of reduced sulfur compounds and its potential impact on the cycling of nitrogen we aimed to get an indication about the key players in the oxidation of sulfide in the Guaymas Basin sediments using the alpha subunit of the adenosine-5’-phosphosulfate (APS reductase (aprA. Amplification of the aprA gene revealed a high number of gammaproteobacterial aprA genes covering the two sulfur-oxidizing bacteria aprA lineages as well as

Presence and diversity of anammox bacteria in cold hydrocarbon-rich seeps and hydrothermal vent sediments of the Guaymas Basin.

Science.gov (United States)

Russ, Lina; Kartal, Boran; Op den Camp, Huub J M; Sollai, Martina; Le Bruchec, Julie; Caprais, Jean-Claude; Godfroy, Anne; Sinninghe Damsté, Jaap S; Jetten, Mike S M

2013-01-01

Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox) bacteria but this has not been investigated in detail. Here we report the diversity and abundance of anammox bacteria in sediments that seep cold hydrocarbon-rich fluids and hydrothermal vent areas of the Guaymas Basin in the Cortés Sea using the unique functional anammox marker gene, hydrazine synthase (hzsA). All clones retrieved were closely associated to the "Candidatus Scalindua" genus. Phylogenetic analysis revealed two distinct clusters of hzsA sequences (Ca. Scalindua hzsA cluster I and II). Comparison of individual sequences from both clusters showed that several of these sequences had a similarity as low as 76% on nucleotide level. Based on the analysis of this phylomarker, a very high interspecies diversity within the marine anammox group is apparent. Absolute numbers of anammox bacteria in the sediments samples were determined by amplification of a 257 bp fragment of the hszA gene in a qPCR assay. The results indicate that numbers of anammox bacteria are generally higher in cold hydrocarbon-rich sediments compared to the vent areas and the reference zone. Ladderanes, lipids unique to anammox bacteria were also detected in several of the sediment samples corroborating the hzsA analysis. Due to the high concentrations of reduced sulfur compounds and its potential impact on the cycling of nitrogen we aimed to get an indication about the key players in the oxidation of sulfide in the Guaymas Basin sediments using the alpha subunit of the adenosine-5'-phosphosulfate (APS) reductase (aprA). Amplification of the aprA gene revealed a high number of gammaproteobacterial aprA genes covering the two sulfur-oxidizing bacteria aprA lineages as well as sulfate-reducers.

Total organic carbon, an important tool in a holistic approach to hydrocarbon source fingerprinting

International Nuclear Information System (INIS)

Boehm, P.D.; Burns, W.A.; Page, D.S.; Bence, A.E.; Mankiewicz, P.J.; Brown, J.S.; Douglas, G.S.

2002-01-01

Total organic carbon (TOC) was used to verify the consistency of source allocation results for the natural petrogenic hydrocarbon background of the northern Gulf of Alaska and Prince William Sound where the Exxon Valdez oil spill occurred in 1998. The samples used in the study were either pre-spill sediments or from the seafloor outside the spill path. It is assumed that the natural petrogenic hydrocarbon background in the area comes from either seep oil residues and shale erosion including erosion from petroleum source rock shales, or from coals including those of the Bering River coalfields. The objective of this study was to use the TOC calculations to discriminate between the two very different sources. TOC can constrain the contributions of specific sources and rule out incorrect source allocations, particularly when inputs are dominated by fossil organic carbon. The benthic sediments used in this study showed excellent agreement between measured TOC and calculated TOC from hydrocarbon fingerprint matches of polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers. TOC and fingerprint matches confirmed that TOC sources were properly identified. The matches quantify the hydrocarbon contributions of different sources to the benthic sediments and the degree of hydrocarbon winnowing by waves and currents. It was concluded that the natural petrogenic hydrocarbon background in the sediments in the area comes from eroding Tertiary shales and oil seeps along the northern Gulf of Alaska coast. Thermally mature area coals are excluded from being important contributors to the background at Prince William Sound because of their high TOC content. 26 refs., 4 figs

Total organic carbon, an important tool in a holistic approach to hydrocarbon source fingerprinting

Energy Technology Data Exchange (ETDEWEB)

Boehm, P.D. [Battelle, Waltham, MA (United States); Burns, W.A. [W.A. Burns Consulting Services, Houston, TX (United States); Page, D.S. [Bowdoin College, Brunswick, ME (United States); Bence, A.E.; Mankiewicz, P.J. [ExxonMobil Upstream Research Co., Houston, TX (United States); Brown, J.S.; Douglas, G.S. [Battelle, Duxbury, MA (United States)

2002-07-01

Total organic carbon (TOC) was used to verify the consistency of source allocation results for the natural petrogenic hydrocarbon background of the northern Gulf of Alaska and Prince William Sound where the Exxon Valdez oil spill occurred in 1998. The samples used in the study were either pre-spill sediments or from the seafloor outside the spill path. It is assumed that the natural petrogenic hydrocarbon background in the area comes from either seep oil residues and shale erosion including erosion from petroleum source rock shales, or from coals including those of the Bering River coalfields. The objective of this study was to use the TOC calculations to discriminate between the two very different sources. TOC can constrain the contributions of specific sources and rule out incorrect source allocations, particularly when inputs are dominated by fossil organic carbon. The benthic sediments used in this study showed excellent agreement between measured TOC and calculated TOC from hydrocarbon fingerprint matches of polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers. TOC and fingerprint matches confirmed that TOC sources were properly identified. The matches quantify the hydrocarbon contributions of different sources to the benthic sediments and the degree of hydrocarbon winnowing by waves and currents. It was concluded that the natural petrogenic hydrocarbon background in the sediments in the area comes from eroding Tertiary shales and oil seeps along the northern Gulf of Alaska coast. Thermally mature area coals are excluded from being important contributors to the background at Prince William Sound because of their high TOC content. 26 refs., 4 figs.

Thyasirid bivalves from Cretaceous and Paleogene cold seeps

Directory of Open Access Journals (Sweden)

Krzysztof Hryniewicz

2017-11-01

Full Text Available We present a systematic study of thyasirid bivalves from Cretaceous to Oligocene seep carbonates worldwide. Eleven species of thyasirid bivalves are identified belonging to three genera: Conchocele, Maorithyas, and Thyasira. Two species are new: Maorithyas humptulipsensis sp. nov. from middle Eocene seep carbonates in the Humptulips Formation, Washington State, USA, and Conchocele kiritachiensis sp. nov. from the late Eocene seep deposit at Kiritachi, Hokkaido, Japan. Two new combinations are provided: Conchocele townsendi (White, 1890 from Maastrichtian strata of the James Ross Basin, Antarctica, and Maorithyas folgeri (Wagner and Schilling, 1923 from Oligocene rocks from California, USA. Three species are left in open nomenclature. We show that thyasirids have Mesozoic origins and appear at seeps before appearing in “normal” marine environments. These data are interpreted as a record of seep origination of thyasirids, and their subsequent dispersal to non-seep environments. We discuss the age of origination of thyasirids in the context of the origin of the modern deep sea fauna and conclude that thyasirids could have deep sea origins. This hypothesis is supported by the observed lack of influence of the Cretaceous and Paleogene Oceanic Anoxic Events on the main evolutionary lineages of the thyasirids, as seen in several other members of the deep sea fauna.

Species distribution and population connectivity of deep-sea mussels at hydrocarbon seeps in the Gulf of Mexico.

Directory of Open Access Journals (Sweden)

Baptiste Faure

Full Text Available Hydrocarbon seepage is widespread and patchy in the Gulf of Mexico, and six species of symbiont containing bathymodiolin mussels are found on active seeps over wide and overlapping depth and geographic ranges. We use mitochondrial genes to discriminate among the previously known and a newly discovered species and to assess the connectivity among populations of the same species in the northern Gulf of Mexico (GoM. Our results generally validate the morphologically based distribution of the three previously known GoM species of Bathymodiolus, although we found that approximately 10% of the morphologically based identifications were incorrect and this resulted in some inaccuracies with respect to their previously assigned depth and geographical distribution patterns. These data allowed us to confirm that sympatry of two species of Bathymodiolus within a single patch of mussels is common. A new species of bathymodiolin, Bathymodiolus sp. nov., closely related to B. heckerae was also discovered. The two species live at the same depths but have not been found in sympatry and both have small effective population sizes. We found evidence for genetic structure within populations of the three species of Bathymodiolinae for which we had samples from multiple sites and suggest limited connectivity for populations at some sites. Despite relatively small sample sizes, genetic diversity indices suggest the largest population sizes for B. childressi and Tamu fisheri and the smallest for B. heckerae and B. sp. nov. among the GoM bathymodiolins. Moreover, we detected an excess of rare variants indicating recent demographic changes and population expansions for the four species of bathymodiolins from the Gulf of Mexico.

Natural gas seeps in the French Alps: Sources and pathways

Science.gov (United States)

Kloppmann, Wolfram; Blessing, Michaela; Proust, Eric; Gal, Frédéric; Bentivegna, Gaetan; Henry, Benoit; Defossez, Pierrick; Catherine, Lerouge; Humez, Pauline; Mayer, Bernhard; Millot, Romain; Gaucher, Eric

2016-04-01

Natural gas emanations are part of the geochemical baseline to take into account when assessing global greenhouse gas emissions and potential impacts of conventional and unconventional gas exploration and exploitation on groundwater. Examples of such natural gas macro-seeps are known in several parts of the world (Etiope et al., 2009). Only a limited number of them have been characterized for their gas and isotopic compositions. Such analyses can provide essential information for baseline studies, providing insight in the sources (biogenic vs. thermogenic or modified thermogenic) and pathways of such seeps and may allow for distinction of natural seeps from stray gas leakage associated with human activities. Here, we report gas concentrations and multi-isotope data (δ13C and δ2H of methane and ethane, δ13C and δ18O of CO2, 3He/4He ratio) of two gas seeps in the French subalpine chains, both in a similar geological and structural position within Middle Jurassic claystones along the eastern border of the large synclinal structures of the Vercors and the Chartreuse massifs (Moss, 1992). The "ardent fountain" (fontaine ardente) of Le Gua, 30 km south of Grenoble has most likely the longest continuous written record of existence of any individual natural gas seep, mentioned explicitly as early as the first quarter of the 5th century (Augustin of Hippo (St. Augustin), approx. 426) This natural seep was described in the past as a "wet seep" associated with a spring, whereas the second investigated seep, Rochasson near Meylan north of Grenoble, is a dry seep. Both seeps contain methane and ethane with thermogenic C and H isotope signatures, comparable with a seep in the Northern Swiss Alps at Giswil (Etiope et al., 2010) but with a higher dryness (C1/(C2+C3)>1000) for the Le Gua seep, possibly due to molecular fractionation upon advective fluid+gas migration (Etiope et al., 2009). Maturity (R0) of the reservoir rocks deduced from δ13C(CH4), δ13C(C2H6) is similar to

Geomicrobiological linkages between short-chain alkane consumption and sulfate reduction rates in seep sediments.

Directory of Open Access Journals (Sweden)

Arpita eBose

2013-12-01

Full Text Available Marine hydrocarbon seeps are ecosystems that are rich in methane, and, in some cases, short-chain (C2-C5 and longer alkanes. C2-C4 alkanes such as ethane, propane and butane can be significant components of seeping fluids. Some sulfate-reducing microbes oxidize short-chain alkanes anaerobically, and may play an important role in both the competition for sulfate and the local carbon budget. To better understand the anaerobic oxidation of short-chain n-alkanes coupled with sulfate-reduction, hydrocarbon-rich sediments from the Gulf of Mexico were amended with artificial, sulfate-replete seawater and one of four n-alkanes (C1-C4 then incubated under strict anaerobic conditions. Measured rates of alkane oxidation and sulfate reduction closely follow stoichiometric predictions that assume the complete oxidation of alkanes to CO2 (though other sinks for alkane carbon likely exist. Changes in the δ13C of all the alkanes in the reactors show enrichment over the course of the incubation, with the C3 and C4 incubations showing the greatest enrichment (4.4‰ and 4.5‰ respectively. The concurrent depletion in the δ13C of dissolved inorganic carbon (DIC implies a transfer of carbon from the alkane to the DIC pool (-3.5 and -6.7‰ for C3 and C4 incubations, respectively. Microbial community analyses reveal that certain members of the class Deltaproteobacteria are selectively enriched as the incubations degrade C1-C4 alkanes. Phylogenetic analyses indicate that distinct phylotypes are enriched in the ethane reactors, while phylotypes in the propane and butane reactors align with previously identified C3-C4 alkane-oxidizing sulfate-reducers. These data further constrain the potential influence of alkane oxidation on sulfate reduction rates in cold hydrocarbon-rich sediments, provide insight into their contribution to local carbon cycling, and illustrate the extent to which short-chain alkanes can serve as electron donors and govern microbial community

Enriched groundwater seeps in two Vermont headwater catchments are hotspots of nitrate turnover

Science.gov (United States)

Kaur, Amninder J.; Ross, Donald S.; Shanley, James B.; Yatzor, Anna R.

2016-01-01

Groundwater seeps in upland catchments are often enriched relative to stream waters, higher in pH, Ca2+ and sometimes NO3¯. These seeps could be a NO3¯ sink because of increased denitrification potential but may also be ‘hotspots’ for nitrification because of the relative enrichment. We compared seep soils with nearby well-drained soils in two upland forested watersheds in Vermont that are sites of ongoing biogeochemical studies. Gross N transformation rates were measured over three years along with denitrification rates in the third year. Gross ammonification rates were not different between the seep and upland soils but gross nitrification rates were about 3 × higher in the seep soils. Net nitrification rates trended higher in the upland soils and NO3¯ consumption (gross—net) was 8 times higher in the seep soils. The average denitrification rate for seep soils was about equal to the difference in NO3¯ consumption between seep and upland soils, suggesting denitrification can make up the difference. Temporal variation in seep water NO3¯ concentration was correlated with watershed outlet NO3¯ concentration. However, it is not clear that in-seep processes greatly altered seep water NO3¯ contribution to the streams. Seep soils appear to be hotspots of both nitrification and denitrification.

Bedded Barite Deposits from Sonora (nw Mexico): a Paleozoic Analog for Modern Cold Seeps

Science.gov (United States)

Canet, C.; Anadón, P.; González-Partida, E.; Alfonso, P.; Rajabi, A.; Pérez-Segura, E.; Alba-Aldave, L. A.

2013-05-01

The Mazatán barite deposits represent an outstanding example of Paleozoic bedded barite, a poorly understood type of mineral deposit of major economic interest. The largest barite bodies of Mazatán are hosted within an Upper Carboniferous flysch succession, which formed part of an accretionary wedge related to the subduction of the Rheic Ocean beneath Gondwana. As well, a few barite occurrences are hosted in Upper Devonian, pre-orogenic turbidites. A variety of mineralized structures is displayed by barite, including: septaria nodules, enterolitic structures, rosettes and debris-flow conglomerates. Barite is accompanied by chalcedony, pyrite (framboids) and berthierine. Gas-rich fluid inclusions in barite were analyzed by Raman spectroscopy and methane was identified, suggesting the occurrence of light hydrocarbons in the environment within which barite precipitated. 13C-depleted carbonates (δ13C: -24.3 to -18.8‰) were found in the barite deposits; they formed through anaerobic oxidation of methane coupled to sulfate reduction, and yield negative δ18O values (-11.9 to -5.2‰) reflecting the isotopic composition of Devonian-Carboniferous seawater. Methane-derived carbonates occur in modern hydrocarbon seeps and have been reported from Mesozoic and Cenozoic seep sediments, but they have never before been described in Paleozoic bedded barite deposits. δ34S of barite varies from +17.6 to +64.1‰, with the lowest values overlapping the range for coeval seawater sulfate; this distribution indicates a process of sulfate reduction. Barite precipitation can be explained by mixing of methane- and barium-rich fluids with pore-water (seawater) containing sulfate residual from microbial reduction. Two analyses from barite gave an 87Sr/86Sr within and slightly above the range for seawater at the time of deposition, with 0.708130 and 0.708588, which would preclude the involvement of hydrothermal fluids in the mineralization process.

Preliminary Engineering Report contaminated groundwater seeps 317/319/ENE area

International Nuclear Information System (INIS)

1996-01-01

When the Resource Conservation and Recovery Act Facility Investigation (RFI) in the 317/319/ENE Area of Argonne National Laboratory-East (ANL-E) was being completed, groundwater was discovered moving to the surface through a series of seeps. The seeps are located approximately 600 ft south of the ANL fence line in Waterfall Glen Forest Preserve. Samples of this water were collected and analyzed for selected parameters. Two of five seeps sampled were found to contain detectable levels of organic contaminants. Three chemical species were identified: chloroform (14-25 μg/L), carbon tetrachloride (56-340 μg/L), and tetrachloroethylene (3-6 μg/L). The other seeps did not contain detectable levels of volatile organic compounds (VOCs). The water issuing from these two contaminated seeps flows into a narrow ravine, where it is visible as a trickle of water flowing through sand and gravel deposits on the floor of the ravine. Approximately 100-ft downstream of the seep area, the contaminated water is no longer visible, having drained back into the soil in the bed of the ravine. Figure 1 shows the location of the 317/319/ENE Area in relation to the ANL-E site and the Waterfall Glen Forest Preserve

Geochemical Tracers and Rates of Short-Chain Alkane Production in Gulf of Mexico Cold Seep Sediments

Science.gov (United States)

Sibert, R.; Bernard, B. B.; Brooks, J. M.; Hunter, K.; Joye, S. B.

2014-12-01

The organic-rich cold seep sediments in the deep Gulf of Mexico commonly contain mixtures of light hydrocarbon gases either dissolved in pore fluids, adsorbed to sediment particles, trapped in methane ice, or as free gas. The dominant component in these natural gas mixtures is typically methane (C1), but ethane (C2) and propane (C3) are nearly always present in trace or major amounts. The ratio of C1:C2:C3 varies but C2 and C3 are typically present at single digit percent levels, whereas methane usually dominates at >80%. Methane production proceeds by at least two well-studied mechanisms: either 1) by thermocatalytic cracking of fossil organic matter, or 2) as a direct product of microbial metabolism, methanogenesis. In contrast, ethane and propane production in deep-sea sediments has been historically attributed only to thermocatalytic processes. However, limited data suggests production of C2/C3 compounds through the activity of archaea. Such studies of microbial- driven dynamics of C2/C3 gases (i.e. 'alkanogenesis') in cold seep sediments are rare. Furthermore, the identities of potential substrates are poorly constrained and no attempt has been made to quantify production rates of C2/C3 gases. However, carbon isotopic data on ethane and propane from deep cores from the Gulf of Mexico suggest alkanogenesis at depth in the sediment column and alkane oxidation in uppermost oxidant-rich sediments. Here, we present the results of a series of incubation experiments using sediment slurries culled from GC600, one of the most prolific natural oil and gas seeps in the Gulf of Mexico. Rates of both alkane production and oxidation were measured under a variety of conditions to assess the net rates of alkane production and elucidate the driving microbiological mechanisms and controls on the central processes of >C1 alkane cycling in cold seep sediments. Microbial processes are important both in terms of alkane production and oxidation, raising many questions as to the

Field Exploration of Methane Seep Near Atqasuk

Energy Technology Data Exchange (ETDEWEB)

Katey Walter, Dennis Witmer, Gwen Holdmann

2008-12-31

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

Using comprehensive two-dimensional gas chromatography to explore the geochemistry of the Santa Barbara oil seeps

Energy Technology Data Exchange (ETDEWEB)

Reddy, Christopher; Nelson, Robert

2013-03-27

The development of comprehensive two-dimensional gas chromatography (GC x GC) has expanded the analytical window for studying complex mixtures like oil. Compared to traditional gas chromatography, this technology separates and resolves at least an order of magnitude more compounds, has a much larger signal to noise ratio, and sorts compounds based on their chemical class; hence, providing highly refined inventories of petroleum hydrocarbons in geochemical samples that was previously unattainable. In addition to the increased resolution afforded by GC x GC, the resulting chromatograms have been used to estimate the liquid vapor pressures, aqueous solubilities, octanol-water partition coefficients, and vaporization enthalpies of petroleum hydrocarbons. With these relationships, powerful and incisive analyses of phase-transfer processes affecting petroleum hydrocarbon mixtures in the environment are available. For example, GC x GC retention data has been used to quantitatively deconvolve the effects of phase transfer processes such as water washing and evaporation. In short, the positive attributes of GC x GC-analysis have led to a methodology that has revolutionized the analysis of petroleum hydrocarbons. Overall, this research has opened numerous fields of study on the biogeochemical "genetics" (referred to as petroleomics) of petroleum samples in both subsurface and surface environments. Furthermore, these new findings have already been applied to the behavior of oil at other seeps as well, for petroleum exploration and oil spill studies.

Bacterial Endophytes Isolated from Plants in Natural Oil Seep Soils with Chronic Hydrocarbon Contamination

OpenAIRE

Lumactud, Rhea; Shen, Shu Yi; Lau, Mimas; Fulthorpe, Roberta

2016-01-01

The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species....

Formation and migration of Natural Gases: gas composition and isotopes as monitors between source, reservoir and seep

Science.gov (United States)

Schoell, M.; Etiope, G.

2015-12-01

Natural gases form in tight source rocks at temperatures between 120ºC up to 200ºC over a time of 40 to 50my depending on the heating rate of the gas kitchen. Inferring from pyrolysis experiments, gases after primary migration, a pressure driven process, are rich in C2+ hydrocarbons (C2 to C5). This is consistent with gas compositions of oil-associated gases such as in the Bakken Shale which occur in immediate vicinity of the source with little migration distances. However, migration of gases along porous rocks over long distances (up to 200km in the case of the Troll field offshore Norway) changes the gas composition drastically as C2+ hydrocarbons tend to be retained/sequestered during migration of gas as case histories from Virginia and the North Sea will demonstrate. Similar "molecular fractionation" is observed between reservoirs and surface seeps. In contrast to gas composition, stable isotopes in gases are, in general, not affected by the migration process suggesting that gas migration is a steady state process. Changes in isotopic composition, from source to reservoir to surface seeps, is often the result of mixing of gases of different origins. Examples from various gas provinces will support this notion. Natural gas basins provide little opportunity of tracking and identifying gas phase separation. Future research on experimental phase separation and monitoring of gas composition and gas ratio changes e.g. various C2+ compound ratios over C1 or isomer ratios such as iso/n ratios in butane and pentane may be an avenue to develop tracers for phase separation that could possibly be applied to natural systems of retrograde natural condensate fields.

The Anthropogenic Effects of Hydrocarbon Inputs to Coastal Seas: Are There Potential Biogeochemical Impacts?

Science.gov (United States)

Anderson, M. R.; Rivkin, R. B.

2016-02-01

Petroleum hydrocarbon discharges related to fossil fuel exploitation have the potential to alter microbial processes in the upper ocean. While the ecotoxicological effects of such inputs are commonly evaluated, the potential for eutrophication from the constituent organic and inorganic nutrients has been largely ignored. Hydrocarbons from natural seeps and anthropogenic sources represent a measurable source of organic carbon for surface waters. The most recent (1989-1997) estimate of average world-wide input of hydrocarbons to the sea is 1.250 x 1012 g/yr ≈ 1.0 x 1012g C/year. Produced water from offshore platforms is the largest waste stream from oil and gas exploitation and contributes significant quantities of inorganic nutrients such as N, P and Fe. In coastal areas where such inputs are a significant source of these nutrients, model studies show the potential to shift production toward smaller cells and net heterotrophy. The consequences of these nutrient sources for coastal systems and semi enclosed seas are complex and difficult to predict, because (1) there is a lack of comprehensive data on inputs and in situ concentrations and (2) the is no conceptual or quantitative framework to consider their effects on ocean biogeochemical processes. Here we use examples from the North Sea (produced water discharges 1% total riverine input and NH4 3% of the annual riverine nitrogen load), the South China Sea (total petroleum hydrocarbons = 10-1750 μg/l in offshore waters), and the Gulf of Mexico (seeps = 76-106 x 109 gC/yr, Macondo blowout 545 x 109 gC) to demonstrate how hydrocarbon and produced water inputs can influence basin scale biogeochemical and ecosystem processes and to propose a framework to consider these effects on larger scales.

The origin of gas seeps and shallow gas in northern part of South China Sea

Science.gov (United States)

Li, M.; Jin, X.

2003-04-01

vary in different places. Gas chimneys can be found on seafloor, which show blank zone on seismic profiles, locally with pit holes. The geochemical analyses of gas samples from gas seeps indicate its composition is dominated by hydrocarbon gas, the other include CO_2, N_2 and O_2. The gas has high dry index, and heavier δ13C_1.This shows that the gas is of matured- over matured thermogenic gas. The geochemical characteristics of extracts from sediments in the area are similar to those of penetrated source rock of Neogene in the basin, indicating the gas is from the matured source rock in the basin, the diapric zone and fault act as the migration pathway. The gas samples on slope were obtained through degasification of sediments collected by SONNE. Geochemical analyses show that the gas composition is dominated by methane, with high dry index and heavier δ13C_1, belonging to typical thermogenic gas. On maturity chart, the gas samples on upper slope fall in the area near the boundary of condensate, indicating higher maturity, while those on lower slope has lower maturity and fall in the area near oil window. The gas samples from deep sea basin is mixed gas of thermogenic gas and biogas. Therefore, it is reasonable to consider the deep buried source rock as the origin of the gas, and the active faults are the migration pathway. As stated above, the gas seeps and shallow gas in northern part of South China Sea were mainly originated from deep buried source rock, migrated through diapric zone or active faults. Their distribution and occurrence have directly relation with the source rock type and maturity, and the tectonic active of the underlying basins. The petroleum exploration has proved that Yinggehai basin and Qiongdongnan basin on the western part are favored for gas generation, while the Pearl River Mouth Basin and Beibu Gulf basin on the eastern part are favored for oil generation. This may account for the distribution of gas seeps which concentrated in the

Signatures of geochemical changes at methane-seeps as recorded by seep carbonates

OpenAIRE

Himmler, Tobias

2011-01-01

This thesis compiles three manuscripts: (1) The first manuscript (chapter 2.1) contains petrographic and geochemical data of aragonitic seep carbonates from the Makran accretionary prism. High-resolution rare earth element (REE) analysis yield distinct total REE[aragonite] concentrations and shale-normalised REE[aragonite] patterns. The REE variations are ascribed to different pore fluid compositions and accompanied redox changes during aragonite precipitation. (2) The second manuscript (chap...

Assessment of seeps in the vicinity of the Mexican Hat tailings disposal cell

International Nuclear Information System (INIS)

1990-10-01

The Phase II remedial action at the Mexican Hat site began in September 1988, and involved the excavation, transportation, and placement of contaminated materials onto the lower tailings pile. These materials were from the upper tailings pile, portions of the lower tailings pile, off-pile contaminated areas, and demolition material stockpiled at the former-mill site. By December 1989, all of the contaminated soils on the upper tailings pile area and most of the off-pile windblown and waterborne contamination had been removed and placed on the lower pile. Since that time, several seeps have been observed near the site. These seeps and some previously identified seeps may be related to remedial action construction activities or the past disposal of mill tailings at the Mexican Hat site. The objectives of this report are to: summarize the geology and hydrostratigraphy of the site; discuss field investigation of the locations, chronology, and flow rates of the seeps; discuss background groundwater quality, tailings pore fluid characterization, and water quality of the seeps; identify possible sources of the seeps; interpret the data; make recommendations for continued site characterization and assessment

Biogeography and potential exchanges among the atlantic Equatorial belt cold-seep faunas.

Directory of Open Access Journals (Sweden)

Karine Olu

2010-08-01

Full Text Available Like hydrothermal vents along oceanic ridges, cold seeps are patchy and isolated ecosystems along continental margins, extending from bathyal to abyssal depths. The Atlantic Equatorial Belt (AEB, from the Gulf of Mexico to the Gulf of Guinea, was one focus of the Census of Marine Life ChEss (Chemosynthetic Ecosystems program to study biogeography of seep and vent fauna. We present a review and analysis of collections from five seep regions along the AEB: the Gulf of Mexico where extensive faunal sampling has been conducted from 400 to 3300 m, the Barbados accretionary prism, the Blake ridge diapir, and in the Eastern Atlantic from the Congo and Gabon margins and the recently explored Nigeria margin. Of the 72 taxa identified at the species level, a total of 9 species or species complexes are identified as amphi-Atlantic. Similarity analyses based on both Bray Curtis and Hellinger distances among 9 faunal collections, and principal component analysis based on presence/absence of megafauna species at these sites, suggest that within the AEB seep megafauna community structure is influenced primarily by depth rather than by geographic distance. Depth segregation is observed between 1000 and 2000 m, with the middle slope sites either grouped with those deeper than 2000 m or with the shallower sites. The highest level of community similarity was found between the seeps of the Florida escarpment and Congo margin. In the western Atlantic, the highest degree of similarity is observed between the shallowest sites of the Barbados prism and of the Louisiana slope. The high number of amphi-atlantic cold-seep species that do not cluster according to biogeographic regions, and the importance of depth in structuring AEB cold-seep communities are the major conclusions of this study. The hydrothermal vent sites along the Mid Atlantic Ridge (MAR did not appear as "stepping stones" for dispersal of the AEB seep fauna, however, the south MAR and off axis regions

Cold seeps and splay faults on Nankai margin

Science.gov (United States)

Henry, P.; Ashi, J.; Tsunogai, U.; Toki, T.; Kuramoto, S.; Kinoshita, M.; Lallemant, S. J.

2003-04-01

Cold seeps (bacterial mats, specific fauna, authigenic carbonates) are common on the Nankai margin and considered as evidence for seepage of methane bearing fluids. Camera and submersible surveys performed over the years have shown that cold seeps are generally associated with active faults. One question is whether part of the fluids expelled originate from the seismogenic zone and migrate along splay faults to the seafloor. The localisation of most cold seeps on the hanging wall of major thrusts may, however, be interpreted in various ways: (a) footwall compaction and diffuse flow (b) fluid channelling along the fault zone at depths and diffuse flow near the seafloor (c) erosion and channelling along permeable strata. In 2002, new observations and sampling were performed with submersible and ROV (1) on major thrusts along the boundary between the Kumano forearc basin domain and the accretionary wedge domain, (2) on a fault affecting the forearc (Kodaiba fault), (3) on mud volcanoes in the Kumano basin. In area (1) tsunami and seismic inversions indicate that the targeted thrusts are in the slip zone of the To-Nankai 1944 earthquakes. In this area, the largest seep zone, continuous over at least 2 km, coincides with the termination of a thrust trace, indicating local fluid channelling along the edge of the fault zone. Kodaiba fault is part of another splay fault system, which has both thrusting and strike-slip components and terminates westward into an en-echelon fold system. Strong seepage activity with abundant carbonates was found on a fold at the fault termination. One mud volcano, rooted in one of the en-echelon fold, has exceptionally high seepage activity compared with the others and thick carbonate crusts. These observations suggest that fluid expulsion along fault zones is most active at fault terminations and may be enhanced during fault initiation. Preliminary geochemical results indicate signatures differ between seep sites and suggests that the two

Inspection and monitoring plan, contaminated groundwater seeps 317/319/ENE Area, Argonne National Laboratory

International Nuclear Information System (INIS)

1996-01-01

During the course of completing the Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) in the 317/319/East-Northeast (ENE) Area of Argonne National Laboratory-East (ANL-E), groundwater was discovered moving to the surface through a series of groundwater seeps. The seeps are located in a ravine approximately 600 ft south of the ANL-E fence line in Waterfall Glen Forest Preserve. Samples of the seep water were collected and analyzed for selected parameters. Two of the five seeps sampled were found to contain detectable levels of organic contaminants. Three chemical species were identified: chloroform (14--25 microg/L), carbon tetrachloride (56--340 microg/L), and tetrachloroethylene (3--6 microg/L). The other seeps did not contain detectable levels of volatile organics. The nature of the contaminants in the seeps will also be monitored on a regular basis. Samples of surface water flowing through the bottom of the ravine and groundwater emanating from the seeps will be collected and analyzed for chemical and radioactive constituents. The results of the routine sampling will be compared with the concentrations used in the risk assessment. If the concentrations exceed those used in the risk assessment, the risk calculations will be revised by using the higher numbers. This revised analysis will determine if additional actions are warranted

Cuticle hydrocarbons in saline aquatic beetles

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María Botella-Cruz

2017-07-01

Full Text Available Hydrocarbons are the principal component of insect cuticle and play an important role in maintaining water balance. Cuticular impermeability could be an adaptative response to salinity and desiccation in aquatic insects; however, cuticular hydrocarbons have been poorly explored in this group and there are no previous data on saline species. We characterized cuticular hydrocarbons of adults and larvae of two saline aquatic beetles, namely Nebrioporus baeticus (Dytiscidae and Enochrus jesusarribasi (Hydrophilidae, using a gas chromatograph coupled to a mass spectrometer. The CHC profile of adults of both species, characterized by a high abundance of branched alkanes and low of unsaturated alkenes, seems to be more similar to that of some terrestrial beetles (e.g., desert Tenebrionidae compared with other aquatic Coleoptera (freshwater Dytiscidae. Adults of E. jesusarribasi had longer chain compounds than N. baeticus, in agreement with their higher resistance to salinity and desiccation. The more permeable cuticle of larvae was characterized by a lower diversity in compounds, shorter carbon chain length and a higher proportion of unsaturated hydrocarbons compared with that of the adults. These results suggest that osmotic stress on aquatic insects could exert a selection pressure on CHC profile similar to aridity in terrestrial species.

Air-dust-borne associations of phototrophic and hydrocarbon-utilizing microorganisms: promising consortia in volatile hydrocarbon bioremediation.

Science.gov (United States)

Al-Bader, Dhia; Eliyas, Mohamed; Rayan, Rihab; Radwan, Samir

2012-11-01

Aquatic and terrestrial associations of phototrophic and heterotrophic microorganisms active in hydrocarbon bioremediation have been described earlier. The question arises: do similar consortia also occur in the atmosphere? Dust samples at the height of 15 m were collected from Kuwait City air, and analyzed microbiologically for phototrophic and heterotrophic hydrocarbon-utilizing microorganisms, which were subsequently characterized according to their 16S rRNA gene sequences. The hydrocarbon utilization potential of the heterotrophs alone, and in association with the phototrophic partners, was measured quantitatively. The chlorophyte Gloeotila sp. and the two cyanobacteria Nostoc commune and Leptolyngbya thermalis were found associated with dust, and (for comparison) the cynobacteria Leptolyngbya sp. and Acaryochloris sp. were isolated from coastal water. All phototrophic cultures harbored oil vapor-utilizing bacteria in the magnitude of 10(5) g(-1). Each phototrophic culture had its unique oil-utilizing bacteria; however, the bacterial composition in Leptolyngbya cultures from air and water was similar. The hydrocarbon-utilizing bacteria were affiliated with Acinetobacter sp., Aeromonas caviae, Alcanivorax jadensis, Bacillus asahii, Bacillus pumilus, Marinobacter aquaeolei, Paenibacillus sp., and Stenotrophomonas maltophilia. The nonaxenic cultures, when used as inocula in batch cultures, attenuated crude oil in light and dark, and in the presence of antibiotics and absence of nitrogenous compounds. Aqueous and diethyl ether extracts from the phototrophic cultures enhanced the growth of the pertinent oil-utilizing bacteria in batch cultures, with oil vapor as a sole carbon source. It was concluded that the airborne microbial associations may be effective in bioremediating atmospheric hydrocarbon pollutants in situ. Like the aquatic and terrestrial habitats, the atmosphere contains dust-borne associations of phototrophic and heterotrophic hydrocarbon

Source allocation by least-squares hydrocarbon fingerprint matching

Energy Technology Data Exchange (ETDEWEB)

William A. Burns; Stephen M. Mudge; A. Edward Bence; Paul D. Boehm; John S. Brown; David S. Page; Keith R. Parker [W.A. Burns Consulting Services LLC, Houston, TX (United States)

2006-11-01

There has been much controversy regarding the origins of the natural polycyclic aromatic hydrocarbon (PAH) and chemical biomarker background in Prince William Sound (PWS), Alaska, site of the 1989 Exxon Valdez oil spill. Different authors have attributed the sources to various proportions of coal, natural seep oil, shales, and stream sediments. The different probable bioavailabilities of hydrocarbons from these various sources can affect environmental damage assessments from the spill. This study compares two different approaches to source apportionment with the same data (136 PAHs and biomarkers) and investigate whether increasing the number of coal source samples from one to six increases coal attributions. The constrained least-squares (CLS) source allocation method that fits concentrations meets geologic and chemical constraints better than partial least-squares (PLS) which predicts variance. The field data set was expanded to include coal samples reported by others, and CLS fits confirm earlier findings of low coal contributions to PWS. 15 refs., 5 figs.

Tolerance of Antarctic soil fungi to hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Hughes, Kevin A.; Bridge, Paul; Clark, Melody S. [British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET (United Kingdom)

2007-01-01

Little is known about the effects of hydrocarbons and fuel oil on Antarctic filamentous fungi in the terrestrial Antarctic environment. Growth of fungi and bacteria from soils around Rothera Research Station (Adelaide Island, Antarctic Peninsula) was assessed in the presence of ten separate aromatic and aliphatic hydrocarbons [marine gas oil (MGO), dodecane, hexadecane, benzoic acid, p-hydroxybenzoic acid, toluene, phenol, biphenyl, naphthalene and m- and p-xylenes with ethylbenzene]. Aromatic hydrocarbons inhibited soil microbial growth more than aliphatic hydrocarbons. Soil microorganisms from a moss patch, where little previous impact or hydrocarbon contamination had occurred, were less tolerant of hydrocarbons than those from high impact sites. Fungal growth rates of Mollisia sp., Penicillium commune, Mortierella sp., Trichoderma koningii, Trichoderma sp. and Phoma herbarum were assessed in the presence of hydrocarbons. Generally, aromatic hydrocarbons inhibited or stopped hyphal extension, though growth rates increased with some aliphatic hydrocarbons. Hyphal dry weight measurements suggested that Mortierella sp. may be able to use dodecane as sole carbon and energy source. Hydrocarbon-degrading Antarctic fungi may have use in future hydrocarbon spill bioremediation. (author)

First discovery of a cold seep on the continental margin of the central Red Sea

KAUST Repository

Batang, Zenon B.

2012-06-01

A new cold brine seep system with microbial mats and metazoan assemblages was discovered by a remotely operated vehicle (ROV) on the Saudi continental margin of central Red Sea. Now named as Thuwal Seeps, it has a shallow brine pool between 840 and 850. m water depths that is formed by focused brine expulsions from two sites (Seep I: 22°17.3\\'N, 38°53.8\\'E; Seep II: 22°16.9\\'N, 38°53.9\\'E). The seep is located at the base of a steep wall rock closer to the shore (20. km) than to the axial trough (120. km). The brine pool does not exhibit a significant thermal anomaly (<. 0.3°C) and is so far the coldest (21.7°C) and least saline (74‰) among brine pools in the Red Sea. This discovery provides the first direct evidence of a cold seep with associated biota on the continental margin of the Red Sea. © 2011 Elsevier B.V.

Methane Metabolizing Microbial Communities in the Cold Seep Areas in the Northern Continental Shelf of South China Sea

Science.gov (United States)

Wang, F.; Liang, Q.

2016-12-01

Marine sediment contains large amount of methane, estimated approximately 500-2500 gigatonnes of dissolved and hydrated methane carbon stored therein, mainly in continental margins. In localized specific areas named cold seeps, hydrocarbon (mainly methane) containing fluids rise to the seafloor, and support oases of ecosystem composed of various microorganisms and faunal assemblages. South China Sea (SCS) is surrounded by passive continental margins in the west and north and convergent margins in the south and east. Thick organic-rich sediments have accumulated in the SCS since the late Mesozoic, which are continuing sources to form gas hydrates in the sediments of SCS. Here, Microbial ecosystems, particularly those involved in methane transformations were investigated in the cold seep areas (Qiongdongnan, Shenhu, and Dongsha) in the northern continental shelf of SCS. Multiple interdisciplinary analytic tools such as stable isotope probing, geochemical analysis, and molecular ecology, were applied for a comprehensive understanding of the microbe mediated methane transformation in this project. A variety of sediments cores have been collected, the geochemical profiles and the associated microbial distribution along the sediment cores were recorded. The major microbial groups involved in the methane transformation in these sediment cores were revealed, known methane producing and oxidizing archaea including Methanosarcinales, anaerobic methane oxidizing groups ANME-1, ANME-2 and their niche preference in the SCS sediments were found. In-depth comparative analysis revealed the presence of SCS-specific archaeal subtypes which probably reflected the evolution and adaptation of these methane metabolizing microbes to the SCS environmental conditions. Our work represents the first comprehensive analysis of the methane metabolizing microbial communities in the cold seep areas along the northern continental shelf of South China Sea, would provide new insight into the

Bacterial Endophytes Isolated from Plants in Natural Oil Seep Soils with Chronic Hydrocarbon Contamination.

Science.gov (United States)

Lumactud, Rhea; Shen, Shu Yi; Lau, Mimas; Fulthorpe, Roberta

2016-01-01

The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum, and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species. The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except S. canadensis, which was dominated by Gammaproteobacteria. Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M. foliorum showing predominance in D. glomerata and both endophytic bacterial species dominated T. aureum. More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene, or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye. P. flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons (PHCs) substrates tested. Mineralization of toluene and naphthalene was confirmed using gas-chromatography. 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site. To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants.

Bacterial endophytes isolated from plants in natural oil seep soils with chronic hydrocarbon contamination

Directory of Open Access Journals (Sweden)

Rhea eLumactud

2016-05-01

Full Text Available The bacterial endophytic communities of four plants growing abundantly in soils highly contaminated by hydrocarbons were analyzed through culturable and and culture-independent means. Given their tolerance to the high levels of petroleum contamination at our study site, we sought evidence that Achillea millefolium, Solidago canadensis, Trifolium aureum and Dactylis glomerata support high levels of hydrocarbon degrading endophytes. A total of 190 isolates were isolated from four plant species. The isolates were identified by partial 16S rDNA sequence analysis, with class Actinobacteria as the dominant group in all species except Solidago canadensis, which was dominated by Gammaproteobacteria. Microbacterium foliorum and Plantibacter flavus were present in all the plants, with M. foliorum showing predominance in D. glomerata and both endophytic bacterial species dominated T. aureum. More than 50% of the isolates demonstrated degradative capabilities for octanol, toluene, naphthalene, kerosene or motor oil based on sole carbon source growth screens involving the reduction of tetrazolium dye. P. flavus isolates from all the sampled plants showed growth on all the petroleum hydrocarbons substrates tested. Mineralization of toluene and naphthalene was confirmed using gas-chromatography. 16S based terminal restriction fragment length polymorphism analysis revealed significant differences between the endophytic bacterial communities showing them to be plant host specific at this site. To our knowledge, this is the first account of the degradation potential of bacterial endophytes in these commonly occurring pioneer plants that were not previously known as phytoremediating plants.

Hydrothermal Vents and Methane Seeps: Rethinking the Sphere of Influence

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Lisa Ann Levin

2016-05-01

Full Text Available Although initially viewed as oases within a barren deep ocean, hydrothermal vent and methane seep communities are now recognized to interact with surrounding ecosystems on the sea floor and in the water column, and to affect global geochemical cycles. The importance of understanding these interactions is growing as the potential rises for disturbance from oil and gas extraction, seabed mining and bottom trawling. Here we synthesize current knowledge of the nature, extent and time and space scales of vent and seep interactions with background systems. We document an expanded footprint beyond the site of local venting or seepage with respect to elemental cycling and energy flux, habitat use, trophic interactions, and connectivity. Heat and energy are released, global biogeochemical and elemental cycles are modified, and particulates are transported widely in plumes. Hard and biotic substrates produced at vents and seeps are used by benthic background fauna for attachment substrata, shelter, and access to food via grazing or through position in the current, while particulates and fluid fluxes modify planktonic microbial communities. Chemosynthetic production provides nutrition to a host of benthic and planktonic heterotrophic background species through multiple horizontal and vertical transfer pathways assisted by flow, gamete release, animal movements, and succession, but these pathways remain poorly known. Shared species, genera and families indicate that ecological and evolutionary connectivity exists among vents, seeps, organic falls and background communities in the deep sea; the genetic linkages with inactive vents and seeps and background assemblages however, are practically unstudied. The waning of venting or seepage activity generates major transitions in space and time that create links to surrounding ecosystems, often with identifiable ecotones or successional stages. The nature of all these interactions is dependent on water depth, as

Hydrothermal vents and methane seeps: Rethinking the sphere of influence

Science.gov (United States)

Levin, Lisa A.; Baco, Amy; Bowden, David; Colaco, Ana; Cordes, Erik E.; Cunha, Marina; Demopoulos, Amanda W.J.; Gobin, Judith; Grupe, Ben; Le, Jennifer; Metaxas, Anna; Netburn, Amanda; Rouse, Greg; Thurber, Andrew; Tunnicliffe, Verena; Van Dover, Cindy L.; Vanreusel, Ann; Watling, Les

2016-01-01

Although initially viewed as oases within a barren deep ocean, hydrothermal vent and methane seep communities are now recognized to interact with surrounding ecosystems on the sea floor and in the water column, and to affect global geochemical cycles. The importance of understanding these interactions is growing as the potential rises for disturbance from oil and gas extraction, seabed mining and bottom trawling. Here we synthesize current knowledge of the nature, extent and time and space scales of vent and seep interactions with background systems. We document an expanded footprint beyond the site of local venting or seepage with respect to elemental cycling and energy flux, habitat use, trophic interactions, and connectivity. Heat and energy are released, global biogeochemical and elemental cycles are modified, and particulates are transported widely in plumes. Hard and biotic substrates produced at vents and seeps are used by “benthic background” fauna for attachment substrata, shelter, and access to food via grazing or through position in the current, while particulates and fluid fluxes modify planktonic microbial communities. Chemosynthetic production provides nutrition to a host of benthic and planktonic heterotrophic background species through multiple horizontal and vertical transfer pathways assisted by flow, gamete release, animal movements, and succession, but these pathways remain poorly known. Shared species, genera and families indicate that ecological and evolutionary connectivity exists among vents, seeps, organic falls and background communities in the deep sea; the genetic linkages with inactive vents and seeps and background assemblages however, are practically unstudied. The waning of venting or seepage activity generates major transitions in space and time that create links to surrounding ecosystems, often with identifiable ecotones or successional stages. The nature of all these interactions is dependent on water depth, as well as

Faunal and stable isotopic analyses of benthic foraminifera from the Southeast Seep on Kimki Ridge offshore southern California, USA

Science.gov (United States)

McGann, Mary; Conrad, James E.

2018-01-01

We investigated the benthic foraminiferal faunal and stable carbon and oxygen isotopic composition of a 15-cm push core (NA075-092b) obtained on a Telepresence-Enabled cruise to the Southeast Seep on Kimki Ridge offshore southern California. The seep core was taken at a depth of 973 m in the vicinity of a Beggiatoa bacterial mat and vesicomyid clams (Calyptogena) and compared to previously published data of living assemblages from ~ 714 m, four reference cores obtained at ~ 1030 m, and another one at 739 m. All of the reference sites are also from the Inner Continental Borderland but with no evidence of methane seepage.No endemic species were found at the seep site and most of the taxa recovered there have been reported previously from other seep or low oxygen environments. Q- and R-mode cluster analyses clearly illustrated differences in the faunal assemblages of the seep and non-seep sites. The living assemblage at Southeast Seep was characterized by abundant Takayanagia delicata, Cassidulina translucens, and Spiroplectammina biformis, whereas the non-seep San Pedro Basin reference assemblage was comprised primarily of Chilostomella oolina and Globobulimina pacifica. Density and species richness were lower at the seep site compared to the non-seep site, reflecting the harsher living conditions there. The dead assemblage at the seep site was dominated by Gyroidina turgida compared to Cassidulina translucens at the ~ 1030 m non-seep site and Cassidulina translucens, Pseudoparrella pacifica, and Takayanagia delicata at the 739 m non-seep site. Density was three times lower at Southeast Seep than at the non-seep sites of comparable water depth but species richness was ~ 30% higher. Stable carbon isotopic values were considerably depleted in the seep samples compared to the non-seep samples, with a progression from lightest to heaviest average δ13C values evident at the seep site reflecting microhabitat preference and vital effect: the

Reassessment of the hydrocarbons in Prince William Sound and the Gulf of Alaska : identifying the source using partial least squares

International Nuclear Information System (INIS)

Mudge, S.M.

2001-01-01

Since the Exxon Valdez oil spill in Prince William Sound, Alaska there has been much discussion regarding the clean-up and long term fate of the oil. There has also been debate regarding the origin of the background hydrocarbons present within Prince William Sound (PWS) and the Gulf of Alaska (GoA). There is evidence that background (pre-spill) hydrocarbons may come from either nearby coal deposits or from natural oil seeps and eroding source rocks in the region. This paper presented a study in which the multivariate statistical methodology of the Partial Least Squares (PLS) was used to reassess the percentage contribution of coal, seep oil, shales and rivers to the hydrocarbon loading in the GoA. Data was provided by researchers at the National Ocean and Atmospheric Administration (NOAA) and the Bowdoin College, for Exxon. The data was analysed using selected sites as sources in order to develop signatures. The signatures were based on 40 and 136 compounds respectively, including the polyaromatic hydrocarbon (PAH) and terpane biomarkers from the Exxon data. The key components describing the sources were fitted to the data for other sites around the GoA to determine the proportion of the variability described by each source. The large complex datasets can be used to develop complex fingerprints for sources rather than using relatively simplistic ratios between selected compounds. The results indicate that 30 per cent of the signature is common between each source and that the small PAHs are the best diagnostic compounds in the model for the oil signature and the large PAHs are good for coal. Naphthalene, methyl and dimethyl naphthalene are the best markers for the seep oil signature. For the pre-spill background, coals and shales are best defined by the larger PAHs such as perylene and benzo(ghi)perylene. In general, the average partitioning between the two sources across all the sampling sites within the region indicated that 53 per cent is attributable to the

Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan

Directory of Open Access Journals (Sweden)

J. Felden

2013-05-01

Full Text Available The Amon mud volcano (MV, located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulfate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition, and microbial activities over 3 yr, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulfide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. The low microbial activity in the hydrocarbon-vented areas of Amon MV is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport.

Seep Detection using E/V Nautilus Integrated Seafloor Mapping and Remotely Operated Vehicles on the United States West Coast

Science.gov (United States)

Gee, L. J.; Raineault, N.; Kane, R.; Saunders, M.; Heffron, E.; Embley, R. W.; Merle, S. G.

2017-12-01

Exploration Vessel (E/V) Nautilus has been mapping the seafloor off the west coast of the United States, from Washington to California, for the past three years with a Kongsberg EM302 multibeam sonar. This system simultaneously collects bathymetry, seafloor and water column backscatter data, allowing an integrated approach to mapping to more completely characterize a region, and has identified over 1,000 seafloor seeps. Hydrographic multibeam sonars like the EM302 were designed for mapping the bathymetry. It is only in the last decade that major mapping projects included an integrated approach that utilizes the seabed and water column backscatter information in addition to the bathymetry. Nautilus mapping in the Eastern Pacific over the past three years has included a number of seep-specific expeditions, and utilized and adapted the preliminary mapping guidelines that have emerged from research. The likelihood of seep detection is affected by many factors: the environment: seabed geomorphology, surficial sediment, seep location/depth, regional oceanography and biology, the nature of the seeps themselves: size variation, varying flux, depth, and transience, the detection system: design of hydrographic multibeam sonars limits use for water column detection, the platform: variations in the vessel and operations such as noise, speed, and swath overlap. Nautilus integrated seafloor mapping provided multiple indicators of seep locations, but it remains difficult to assess the probability of seep detection. Even when seeps were detected, they have not always been located during ROV dives. However, the presence of associated features (methane hydrate and bacterial mats) serve as evidence of potential seep activity and reinforce the transient nature of the seeps. Not detecting a seep in the water column data does not necessarily indicate that there is not a seep at a given location, but with multiple passes over an area and by the use of other contextual data, an area may

Short-chain alkanes fuel mussel and sponge Cycloclasticus symbionts from deep-sea gas and oil seeps.

Science.gov (United States)

Rubin-Blum, Maxim; Antony, Chakkiath Paul; Borowski, Christian; Sayavedra, Lizbeth; Pape, Thomas; Sahling, Heiko; Bohrmann, Gerhard; Kleiner, Manuel; Redmond, Molly C; Valentine, David L; Dubilier, Nicole

2017-06-19

Cycloclasticus bacteria are ubiquitous in oil-rich regions of the ocean and are known for their ability to degrade polycyclic aromatic hydrocarbons (PAHs). In this study, we describe Cycloclasticus that have established a symbiosis with Bathymodiolus heckerae mussels and poecilosclerid sponges from asphalt-rich, deep-sea oil seeps at Campeche Knolls in the southern Gulf of Mexico. Genomic and transcriptomic analyses revealed that, in contrast to all previously known Cycloclasticus, the symbiotic Cycloclasticus appears to lack the genes needed for PAH degradation. Instead, these symbionts use propane and other short-chain alkanes such as ethane and butane as carbon and energy sources, thus expanding the limited range of substrates known to power chemosynthetic symbioses. Analyses of short-chain alkanes in the environment of the Campeche Knolls symbioses revealed that these are present at high concentrations (in the μM to mM range). Comparative genomic analyses revealed high similarities between the genes used by the symbiotic Cycloclasticus to degrade short-chain alkanes and those of free-living Cycloclasticus that bloomed during the Deepwater Horizon oil spill. Our results indicate that the metabolic versatility of bacteria within the Cycloclasticus clade is higher than previously assumed, and highlight the expanded role of these keystone species in the degradation of marine hydrocarbons.

Food-Web Complexity in Guaymas Basin Hydrothermal Vents and Cold Seeps.

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Marie Portail

Full Text Available In the Guaymas Basin, the presence of cold seeps and hydrothermal vents in close proximity, similar sedimentary settings and comparable depths offers a unique opportunity to assess and compare the functioning of these deep-sea chemosynthetic ecosystems. The food webs of five seep and four vent assemblages were studied using stable carbon and nitrogen isotope analyses. Although the two ecosystems shared similar potential basal sources, their food webs differed: seeps relied predominantly on methanotrophy and thiotrophy via the Calvin-Benson-Bassham (CBB cycle and vents on petroleum-derived organic matter and thiotrophy via the CBB and reductive tricarboxylic acid (rTCA cycles. In contrast to symbiotic species, the heterotrophic fauna exhibited high trophic flexibility among assemblages, suggesting weak trophic links to the metabolic diversity of chemosynthetic primary producers. At both ecosystems, food webs did not appear to be organised through predator-prey links but rather through weak trophic relationships among co-occurring species. Examples of trophic or spatial niche differentiation highlighted the importance of species-sorting processes within chemosynthetic ecosystems. Variability in food web structure, addressed through Bayesian metrics, revealed consistent trends across ecosystems. Food-web complexity significantly decreased with increasing methane concentrations, a common proxy for the intensity of seep and vent fluid fluxes. Although high fluid-fluxes have the potential to enhance primary productivity, they generate environmental constraints that may limit microbial diversity, colonisation of consumers and the structuring role of competitive interactions, leading to an overall reduction of food-web complexity and an increase in trophic redundancy. Heterogeneity provided by foundation species was identified as an additional structuring factor. According to their biological activities, foundation species may have the potential to

Application of parasound data for sediment study on methane seep site at Simeulue basin

International Nuclear Information System (INIS)

Wiguna, Taufan; Ardhyastuti, Sri

2015-01-01

The Parasound data presents sea depth and sub-bottom profiler. In terms of geological terminology, parasound data represents significant recent surface sedimentary structures that valuable for the selection of subsequent sampling site such as sampling at methane seep site. Therefore, Parasound is used to detailing methane seep at surface sediment following seismic data interpretation. In this study, parasound is used to focus observe area especially for sediment study on methane seep site. The Parasound systems works both as narrow beam sounder use high frequency and as sediment echosounder use low frequency. Parasound acquisition applies parametric effect. It produces additional frequency by nonlinear acoustic interaction of finite amplitude waves. Parasound transducers have 128 elements on 1 m2 and need transmission power up to 70 kW. The results of this study are discovered large seep carbonate with porous surface which means there are gas expulsions passing through that rock

Characterization of the acidic cold seep emplaced jarositic Golden Deposit, NWT, Canada, as an analogue for jarosite deposition on Mars

Science.gov (United States)

Battler, Melissa M.; Osinski, Gordon R.; Lim, Darlene S. S.; Davila, Alfonso F.; Michel, Frederick A.; Craig, Michael A.; Izawa, Matthew R. M.; Leoni, Lisa; Slater, Gregory F.; Fairén, Alberto G.; Preston, Louisa J.; Banerjee, Neil R.

2013-06-01

Surficial deposits of the OH-bearing iron sulfate mineral jarosite have been observed in several places on Mars, such as Meridiani Planum and Mawrth Vallis. The specific depositional conditions and mechanisms are not known, but by comparing martian sites to analogous locations on Earth, the conditions of formation and, thus, the martian depositional paleoenvironments may be postulated. Located in a cold semi-arid desert ˜100 km east of Norman Wells, Northwest Territories, Canada, the Golden Deposit (GD) is visible from the air as a brilliant golden-yellow patch of unvegetated soil, approximately 140 m × 50 m. The GD is underlain by permafrost and consists of yellow sediment, which is precipitating from seeps of acidic, iron-bearing groundwater. On the surface, the GD appears as a patchwork of raised polygons, with acidic waters flowing from seeps in troughs between polygonal islands. Although UV-Vis-NIR spectral analysis detects only jarosite, mineralogy, as determined by X-ray diffraction and inductively coupled plasma emission spectrometry, is predominantly natrojarosite and jarosite, with hydronium jarosite, goethite, quartz, clays, and small amounts of hematite. Water pH varies significantly over short distances depending on proximity to acid seeps, from 2.3 directly above seeps, to 5.7 several m downstream from seeps within the deposit, and up to 6.5 in ponds proximal to the deposit. Visual observations of microbial filament communities and phospholipid fatty acid analyses confirm that the GD is capable of supporting life for at least part of the year. Jarosite-bearing sediments extend beneath vegetation up to 70 m out from the deposit and are mixed with plant debris and minerals presumably weathered from bedrock and glacial till. This site is of particular interest because mineralogy (natrojarosite, jarosite, hematite, and goethite) and environmental conditions (permafrost and arid conditions) at the time of deposition are conceivably analogous to jarosite

Total organic carbon, an important tool in an holistic approach to hydrocarbon source fingerprinting

Energy Technology Data Exchange (ETDEWEB)

Boehm, P.D.; Burns, W.A.; Page, D.S.; Bence, A.E.; Mankiewicz, P.J.; Brown, J.S.; Douglas, G.S. [Battelle Member Inst., Waltham, MA (United States)

2002-07-01

The identification and allocation of multiple hydrocarbon sources in marine sediments is best achieved using an holistic approach. Total organic carbon (TOC) is one important tool that can constrain the contributions of specific sources and rule out incorrect source allocations in cases where inputs are dominated by fossil organic carbon. In a study of the benthic sediments from Prince William Sound (PWS) and the Gulf of Alaska (GOA), we find excellent agreement between measured TOC and TOC calculated from hydrocarbon fingerprint matches of polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers. Confirmation by two such independent source indicators (TOC and fingerprint matches) provides evidence that source allocations determined by the fingerprint matches are robust and that the major TOC sources have been correctly identified. Fingerprint matches quantify the hydrocarbon contributions of various sources to the benthic sediments and the degree of hydrocarbon winnowing by waves and currents. TOC contents are then calculated using source allocation results from fingerprint matches and the TOCs of contributing sources. Comparisons of the actual sediment TOC values and those calculated from source allocation support our earlier published findings that the natural petrogenic hydrocarbon background in sediments in this area comes from eroding Tertiary shales and associated oil seeps along the northern GOA coast and exclude thermally mature area coals from being important contributors to the PWS background due to their high TOC content.

Stable carbon, nitrogen and sulfur isotopes in non-carbonate fractions of cold-seep carbonates

Science.gov (United States)

Feng, Dong; Peng, Yongbo; Peckmann, Jörn; Roberts, Harry; Chen, Duofu

2017-04-01

Sulfate-driven anaerobic oxidation of methane (AOM) supports chemosynthesis-based communities and limits the release of methane from marine sediments. This process promotes the formation of carbonates close to the seafloor along continental margins. The geochemical characteristics of the carbonate minerals of these rocks are increasingly understood, questions remain about the geochemical characteristics of the non-carbonate fractions. Here, we report stable carbon, nitrogen and sulfur isotope patterns in non-carbonate fractions of seep carbonates. The authigenic carbonates were collected from three modern seep provinces (Black Sea, Gulf of Mexico, and South China Sea) and three ancient seep deposits (Marmorito, northern Italy, Miocene; SR4 deposit of the Lincoln Creek Formation and Whiskey Creek, western Washington, USA, Eocene to Oligocene). The δ13C values of non-carbonate fractions range from ˜-25‰ to -80‰ VPDB. These values indicate that fossil methane mixed with varying amounts of pelagic organic matter is the dominant source of carbon in these fractions. The relatively small offset between the δ34S signatures of the non-carbonate fractions and the respective sulfide minerals suggests that locally produced hydrogen sulfide is the main source of sulfur in seep environments. The δ15N values of the non-carbonate fractions are generally lower than the corresponding values of deep-sea sediments, suggesting that organic nitrogen is mostly of a local origin. This study reveals the potential of using δ13C, δ15N, δ34S values to discern seep and non-seep deposits. In cases where δ13Ccarbonate values are only moderately low due to mixing processes and lipid biomarkers have been erased in the course of burial, it is difficult to trace back AOM owing to the lack of other records. This problem is even more pronounced when authigenic carbonate is not available in ancient seep environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support

Benthic foraminifera as tools in interpretation of subsurface hydrocarbon fluid flow at Veslemøy High and Hola-Vesterålen areas of the Barents Sea.

Science.gov (United States)

Baranwal, Soma; Sauer, Simone; Knies, Jochen; Chand, Shyam; Jensen, Henning; Klug, Martin

2014-05-01

Relatively few studies have focused on high-latitude benthic foraminifera related to hydrocarbon seeps. In this study, we present micropaleontological data from 8 gravity cores from the Veslemøy High and 4 surface sediments (0-1cm) from Hola-Vesterålen, Norway. The study of hydrocarbon impregnation and its effect on benthic foraminfera was conducted on selected sediment samples from the calcium-rich Holocene sediments of the Veslemøy High. The assemblage of foraminifera have been identified from three regional clusters. Cluster I and II are dominated by benthic foraminifera Buccella, Cassidulina, Cibicides, Discopulvinulina, Epistominella, Pullenia and Trifarina. Cluster III is distinct with an elevated abundance of Cassidulina, Cibicides and Trifarina with significant (>5 %) occurrence of Nonionella and Uvigerina. There is no apparent dissolution on the preserved foraminifera. However, there can be differential dissolution or destruction of the more fragile (thinner-walled test) species like Epistominella, Nonionella or Pullenia while leaving behind over-represented species like Cibicides or Trifarina (both preferring coarse grained, high energy areas that can withstand permanent winnowing and redeposition) with higher preservation potential. Also, Cluster III is placed right over the underlying fault line with shallow seep-indications and thus the fluids released may have induced the dissolution of the fragile species. Moreover, the significant occurrence of benthic foraminifera Nonionella auris, and Uvigerina peregrina, in Holocene deposits of Cluster III may be indicative of environments influenced by hydrocarbon migration to the seafloor. Previous studies have reported active natural hydrocarbon seepage in the Hola area and the stable carbon and hydrogen isotopic composition of methane in the sediments suggests a predominantly thermogenic methane source. The seep-assemblage is composed of Cibicides (~60%), Cassidulina, Discanomalina, Textularia and

The ground support computer and in-orbit survey data analysis program for the SEEP experiment

International Nuclear Information System (INIS)

Voss, H.D.; Datlowe, D.W.; Mobilia, J.; Roselle, S.N.

1985-01-01

The ground support computer equipment (GSE) and production survey plot and analysis software are described for the Stimulated Emissions of Energetic Particles (SEEP) experiment on the S81-1 satellite. A general purpose satellite data acquisition circuit was developed based on a Z-80 portable microcomputer. By simply changing instrument control software and electrical connectors, automatic testing and control of the various SEEP instruments was accomplished. A new feature incorporated into the SEEP data analysis phase was the development of a correlative data base for all of the SEEP instruments. A CPU efficient survey plot program (with ephemeris) was developed to display the approximate 3100 hours of data, with a time resolution of 0.5 sec, from the ten instrument sensors. The details of the general purpose multigraph algorithms and plot formats are presented. For the first time new associations are being investigated of simultaneous particle, X-ray, optical and plasma density satellite measurements

The microbial nitrogen cycling potential in marine sediments is impacted by polyaromatic hydrocarbon pollution

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Nicole M Scott

2014-03-01

Full Text Available During petroleum hydrocarbon exposure the composition and functional dynamics of marine microbial communities are altered, favoring bacteria that can utilize this rich carbon source. Initial exposure of high levels of hydrocarbons in aerobic surface sediments can enrich growth of heterotrophic microorganisms having hydrocarbon degradation capacity. As a result, there can be a localized reduction in oxygen potential, if the sediments are aerobic, within the surface layer of marine sediments resulting in anaerobic zones. We hypothesized that increasing exposure to elevated hydrocarbon concentrations would positively correlate with an increase in denitrification processes and the net accumulation of dinitrogen. This hypothesis was tested by comparing the relative abundance of genes associated with nitrogen metabolism and nitrogen cycling identified in 6 metagenomes from sediments contaminated by polyaromatic hydrocarbons from the Deepwater Horizon oil spill in the Gulf of Mexico, and 3 metagenomes from sediments associated with natural oil seeps in the Santa Barbara Channel. An additional 8 metagenomes from uncontaminated sediments from the Gulf of Mexico were analyzed for comparison. We predicted relative changes in metabolite turnover as a function of the differential microbial gene abundances, which showed predicted accumulation of metabolites associated with denitrification processes, including anammox, in the contaminated samples compared to uncontaminated sediments, with the magnitude of this change being positively correlated to the hydrocarbon concentration and exposure duration. These data highlight the potential impact of hydrocarbon inputs on N cycling processes in marine sediments and provide information relevant for system scale models of nitrogen metabolism in affected ecosystems.

Microbial diversity in cold seep sediments from the northern South China Sea

Directory of Open Access Journals (Sweden)

Yong Zhang

2012-05-01

Full Text Available South China Sea (SCS is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, “SONNE” 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diversity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abundance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment (wet weight. The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diversity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively.

Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

Science.gov (United States)

Demopoulos, Amanda W.J.; Gualtieri, Daniel; Kovacs, Kaitlin

2010-01-01

The slope environment of the Gulf of Mexico (GOM) supports dense communities of seep megafaunal invertebrates that rely on endosymbiotic bacteria for nutrition. Seep sediments also contain smaller macrofaunal invertebrates whose nutritional pathways are not well understood. Using stable-isotope analysis, we investigate the utilization of chemosynthetically fixed and methane-derived organic matter by macrofauna. Biological sampling was conducted in three lower-slope GOM seep environs: Green Canyon (GC852, 1428 m), Atwater Valley (AT340, 2230 m), and Alaminos Canyon (AC601, 2384 m). Infaunal delta13C and delta15N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light delta15N and delta13C values, indicating possible reliance on chemoautotrophic symbioses. The lightest delta13C and delta15N values were observed in nematodes (delta13C=-54.6 + or - 0.1 per mil, delta15N=-6.1 + or - 0.2 per mil) and one gastropod (delta13C=-54.1 per mil, delta15N=-1.1 per mil) from Green Canyon. Mixing-model results indicated that sulfur-oxidizing Beggiatoa may be an important food source for seep infauna; the rate of utilization ranged from 60% to 100% at Green Canyon and Atwater Valley. The overall range in isotope values was similar across the three sites, suggesting that biogeochemical processes may be very similar in these geographically distinct areas.

Laser fluorosensor overflights of the Santa Barbara oil seeps

Energy Technology Data Exchange (ETDEWEB)

Brown, C. E.; Nelson, R. D.; Fingas, M. [Environment Canada, Ottawa, ON (Canada). Emergencies Science Div.; Mullin, J. V. [Minerals Management Service, Herndon, VA (United States)

1997-10-01

Environment Canada`s Laser Environmental Airborne Fluorosensor (LEAF) system was tested in a series of overflights over naturally occurring oil seeps off Santa Barbara, California. The objective was to test the system`s ability to detect oil in actual marine environments and to distinguish petroleum oil from biogenic oils released by kelp beds in and around these naturally occurring oil seep areas. High resolution colour reconnaissance camera images and down-looking video images were collected concurrently with the fluorescence data for documentation purposes. Results of the experiment were analyzed in detail. They confirmed the system`s ability to produce geo-referenced oil contamination location maps in real-time. The fluorescence data obtained during overflights was most similar to typical crude oil, i. e. the system successfully distinguished between biogenic oil and typical petroleum oil. 9 refs., 1 tab., 3 figs.

Laser fluorosensor overflights of the Santa Barbara oil seeps

International Nuclear Information System (INIS)

Brown, C. E.; Nelson, R. D.; Fingas, M.

1997-01-01

Environment Canada's Laser Environmental Airborne Fluorosensor (LEAF) system was tested in a series of overflights over naturally occurring oil seeps off Santa Barbara, California. The objective was to test the system's ability to detect oil in actual marine environments and to distinguish petroleum oil from biogenic oils released by kelp beds in and around these naturally occurring oil seep areas. High resolution colour reconnaissance camera images and down-looking video images were collected concurrently with the fluorescence data for documentation purposes. Results of the experiment were analyzed in detail. They confirmed the system's ability to produce geo-referenced oil contamination location maps in real-time. The fluorescence data obtained during overflights was most similar to typical crude oil, i. e. the system successfully distinguished between biogenic oil and typical petroleum oil. 9 refs., 1 tab., 3 figs

Analysis of past recurrent methane seep activity using radiocarbon dating of Calyptogena spp. shells in the eastern Nankai subduction zone, Japan

Science.gov (United States)

Yagasaki, Kazuhiro; Ashi, Juichiro; Yokoyama, Yusuke; Miyairi, Yosuke; Kuramoto, Shin'ichi

2016-04-01

Fault activity around subduction zones have been widely studied and monitored through drilling of oceanic plates, studying piston cores, use of monitoring equipment or through visual analysis using submersible vehicles. Yet the understanding of how small scale faults near shallow regions of the seabed behave in relation to cold seep vent activity is still vague, especially determining when they were active in the past. In tectonically active margins such as the Nankai and Tokai regions off Japan, dense methane hydrate reservoirs have been identified. Cold seeps releasing methane rich hydrocarbon fluids are common here, supporting a wide variety of biological species that hold a symbiotic relationship with the chemosynthetic bacteria. In 1998 a large dead Calyptogena spp. bivalve colony (over 400m2 in size) was discovered off Tokai, Japan. It is unusual for a bivalve colony this size to mostly be dead, raising questions as to what caused their death. In this study we document the radiocarbon 14C age of these bivalve shells to attempt analysing the possible methane seep bahaviour in the past. The measured 14C age ranged in three age groups of 1396±36-1448±34, 1912±31-1938±35 and 5975±34. The 14C age of shells that were alive upon collection and the dissolved inorganic carbon (DIC) in seawater show little difference (˜100 14C age) indicating that shells are not heavily affected by the dead carbon effect from cold seeps that is of biogenic or thermogenic origin, which can make the age to become considerably older than the actual age. Thus the novel calibration model used was based on the seawater DIC collected above the Calyptogena spp. colony site (1133±31), which resulted in the dead shells to be clustered around 1900 Cal AD. This proves to be interesting as the predicted epicenter of the Ansei-Tokai earthquake (M 8.4) in 1854 is extremely close to the bibalve colony site. Using geological data obtained using visual analysis and sub-seafloor structural

Methane Seep in Shallow-Water Permeable Sediment Harbors High Diversity of Anaerobic Methanotrophic Communities, Elba, Italy

Science.gov (United States)

Ruff, S. Emil; Kuhfuss, Hanna; Wegener, Gunter; Lott, Christian; Ramette, Alban; Wiedling, Johanna; Knittel, Katrin; Weber, Miriam

2016-01-01

The anaerobic oxidation of methane (AOM) is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB), and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic carbon depleted permeable sands off the Island of Elba (Italy). We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g-1 day-1 indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20–50 cm below seafloor) as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3, and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise distinct

Methane Seep in Shallow-Water Permeable Sediment Harbors High Diversity of Anaerobic Methanotrophic Communities, Elba, Italy.

Science.gov (United States)

Ruff, S Emil; Kuhfuss, Hanna; Wegener, Gunter; Lott, Christian; Ramette, Alban; Wiedling, Johanna; Knittel, Katrin; Weber, Miriam

2016-01-01

The anaerobic oxidation of methane (AOM) is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB), and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic carbon depleted permeable sands off the Island of Elba (Italy). We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g(-1) day(-1) indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20-50 cm below seafloor) as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3, and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise distinct

Soil Iodine Determination in Deccan Syneclise, India: Implications for Near Surface Geochemical Hydrocarbon Prospecting

International Nuclear Information System (INIS)

Mani, Devleena; Kumar, T. Satish; Rasheed, M. A.; Patil, D. J.; Dayal, A. M.; Rao, T. Gnaneshwar; Balaram, V.

2011-01-01

The association of iodine with organic matter in sedimentary basins is well documented. High iodine concentration in soils overlying oil and gas fields and areas with hydrocarbon microseepage has been observed and used as a geochemical exploratory tool for hydrocarbons in a few studies. In this study, we measure iodine concentration in soil samples collected from parts of Deccan Syneclise in the west central India to investigate its potential application as a geochemical indicator for hydrocarbons. The Deccan Syneclise consists of rifted depositional sites with Gondwana–Mesozoic sediments up to 3.5 km concealed under the Deccan Traps and is considered prospective for hydrocarbons. The concentration of iodine in soil samples is determined using ICP-MS and the values range between 1.1 and 19.3 ppm. High iodine values are characteristic of the northern part of the sampled region. The total organic carbon (TOC) content of the soil samples range between 0.1 and 1.3%. The TOC correlates poorly with the soil iodine (r 2 < 1), indicating a lack of association of iodine with the surficial organic matter and the possibility of interaction between the seeping hydrocarbons and soil iodine. Further, the distribution pattern of iodine compares well with two surface geochemical indicators: the adsorbed light gaseous hydrocarbons (methane through butane) and the propane-oxidizing bacterial populations in the soil. The integration of geochemical observations show the occurrence of elevated values in the northern part of the study area, which is also coincident with the presence of exposed dyke swarms that probably serve as conduits for hydrocarbon microseepage. The corroboration of iodine with existing geological, geophysical, and geochemical data suggests its efficacy as one of the potential tool in surface geochemical exploration of hydrocarbons. Our study supports Deccan Syneclise to be promising in terms of its hydrocarbon prospects.

Organic pollutants in the coastal environment off San Diego, California. 2: Petrogenic and biogenic sources of aliphatic hydrocarbons

International Nuclear Information System (INIS)

Tran, K.; Yu, C.C.; Zeng, E.Y.

1997-01-01

The results from the measurements of aliphatic hydrocarbons suggest that hydrocarbons suggest that hydrocarbons in the Point Loma Wastewater Treatment Plant (PLWTP) effluents are mainly petroleum derived; those in the Tijuana River runoff have largely originated from terrestrial plants with visible petroleum contamination; and those in the sea surface microlayer, sediment traps, and sediments at various coastal locations off San Diego have mostly resulted from biogenic contributions with enhanced microbial products in the summer season. Rainfall in the winter season appeared to amplify the inputs from terrestrial higher plants to the coastal areas. The PLWTP discharged approximately 3.85 metric tons of n-alkanes (C 10 -C 35 ) in 1994, well below the level (136 metric tons) estimated in 1979. The input of aliphatic hydrocarbons from the Tijuana River was about 0.101 metric tons in 1994. Diffusion, solubilization, evaporation, and microbial degradation seemed partially responsible for the difference in the concentrations and compositions of aliphatic hydrocarbons in different sample media, although the relative importance of each mechanism cannot be readily discerned from the available data. The results from analyses of aliphatic hydrocarbon compositional indices are generally consistent with those of polycyclic aromatic hydrocarbons

Cold-seep-like macrofaunal communities in organic- and sulfide-rich sediments of the Congo deep-sea fan

Science.gov (United States)

Olu, K.; Decker, C.; Pastor, L.; Caprais, J.-C.; Khripounoff, A.; Morineaux, M.; Ain Baziz, M.; Menot, L.; Rabouille, C.

2017-08-01

Methane-rich fluids arising from organic matter diagenesis in deep sediment layers sustain chemosynthesis-based ecosystems along continental margins. This type of cold seep develops on pockmarks along the Congo margin, where fluids migrate from deep-buried paleo-channels of the Congo River, acting as reservoirs. Similar ecosystems based on shallow methane production occur in the terminal lobes of the present-day Congo deep-sea fan, which is supplied by huge quantities of primarily terrestrial material carried by turbiditic currents along the 800 km channel, and deposited at depths of up to nearly 5000 m. In this paper, we explore the effect of this carbon enrichment of deep-sea sediments on benthic macrofauna, along the prograding lobes fed by the current active channel, and on older lobes receiving less turbiditic inputs. Macrofaunal communities were sampled using either USNEL cores on the channel levees, or ROV blade cores in the chemosynthesis-based habitats patchily distributed in the active lobe complex. The exceptionally high organic content of the surface sediment in the active lobe complex was correlated with unusual densities of macrofauna for this depth, enhanced by a factor 7-8, compared with those of the older, abandoned lobe, whose sediment carbon content is still higher than in Angola Basin at same depth. Macrofaunal communities, dominated by cossurid polychaetes and tanaids were also more closely related to those colonizing low-flow cold seeps than those of typical deep-sea sediment. In reduced sediments, microbial mats and vesicomyid bivalve beds displayed macrofaunal community patterns that were similar to their cold-seep counterparts, with high densities, low diversity and dominance of sulfide-tolerant polychaetes and gastropods in the most sulfidic habitats. In addition, diversity was higher in vesicomyid bivalve beds, which appeared to bio-irrigate the upper sediment layers. High beta-diversity is underscored by the variability of geochemical

Medusa-Isosampler: A modular, network-based observatory system for combined physical, chemical and microbiological monitoring, sampling and incubation of hydrothermal and cold seep fluids

Science.gov (United States)

Schultz, A.; Flynn, M.; Taylor, P.

2004-12-01

The study of life in extreme environments provides an important context from which we can undertake the search for extraterrestrial life, and through which we can better understand biogeochemical feedback in terrestrial hydrothermal and cold seep systems. The Medusa-Isosampler project is aimed at fundamental research into understanding the potential for, and limits to, chemolithoautotrophic life, i.e. primary production without photosynthesis. One environment that might foster such life is associated with the high thermal and chemical gradient environment of hydrothermal vent structures. Another is associated with the lower thermal and chemical gradient environment of continental margin cold seeps. Under NERC, NASA and industrial support, we have designed a flexible instrumentation system, operating as networked, autonomous modules on a local area network, that will make possible simultaneous physical and chemical sampling and monitoring of hydrothermal and cold seep fluids, and the in situ and laboratory incubation of chemosynthetic microbes under high pressure, isobaric conditions. The system has been designed with long-term observatory operations in mind, and may be reconfigured dynamically as the requirements of the observatory installation change. The modular design will also accommodate new in situ chemical and biosensor technologies, provided by third parties. The system may be configured for seafloor use, and can be adapted to use in IODP boreholes. Our overall project goals are provide an instrumentation system capable of probing both high and low-gradient water-rock systems for chemolithoautotrophic biospheres, to identify the physical and chemical conditions that define these microhabitats and explore the details of the biogeochemical feedback loops that mediate these microhabitats, and to attempt to culture and identify chemolithoautotrophic microbial communities that might exist there. The Medusa-Isosampler system has been produced and is now

Succession of Hydrocarbon Degradation and Microbial Diversity during a Simulated Petroleum Seepage in Caspian Sea Sediments

Science.gov (United States)

Mishra, S.; Stagars, M.; Wefers, P.; Schmidt, M.; Knittel, K.; Krueger, M.; Leifer, I.; Treude, T.

2016-02-01

Microbial degradation of petroleum was investigated in intact sediment cores of Caspian Sea during a simulated petroleum seepage using a sediment-oil-flow-through (SOFT) system. Over the course of the SOFT experiment (190 days), distinct redox zones established and evolved in the sediment core. Methanogenesis and sulfate reduction were identified to be important processes in the anaerobic degradation of hydrocarbons. C1 to C6 n-alkanes were completely exhausted in the sulfate-reducing zone and some higher alkanes decreased during the upward migration of petroleum. A diversity of sulfate-reducing bacteria was identified by 16s rRNA phylogenetic studies, some of which are associated with marine seeps and petroleum degradation. The δ13C signal of produced methane decreased from -33.7‰ to -49.5‰ indicating crude oil degradation by methanogenesis, which was supported by enrichment culturing of methanogens with petroleum hydrocarbons and presence of methanogenic archaea. The SOFT system is, to the best of our knowledge, the first system that simulates an oil-seep like condition and enables live monitoring of biogeochemical changes within a sediment core during petroleum seepage. During our presentation we will compare the Caspian Sea data with other sediments we studied using the SOFT system from sites such as Santa Barbara (Pacific Ocean), the North Alex Mud Volcano (Mediterranean Sea) and the Eckernfoerde Bay (Baltic Sea). This research was funded by the Deutsche Forschungsgemeinschaft (SPP 1319) and DEA Deutsche Erdoel AG. Further support came from the Helmholtz and Max Planck Gesellschaft.

Waste Area Grouping 2 Remedial Investigation Phase 1 Seep Task data report: Contaminant source area assessment

International Nuclear Information System (INIS)

Hicks, D.S.

1996-03-01

This report presents the findings of the Waste Area Grouping (WAG) 2, Phase 1 Remedial Investigation (RI) Seep Task efforts during 1993 and 1994 at Oak Ridge National Laboratory (ORNL). The results presented here follow results form the first year of sampling, 1992, which are contained in the Phase 1 RI report for WAG 2 (DOE 1995a). The WAG 2 Seep Task efforts focused on contaminants in seeps, tributaries, and main streams within the White Oak Creek (WOC) watershed. This report is designed primarily as a reference for contaminants and a resource for guiding remedial decisions. Additional in-depth assessments of the Seep Task data may provide clearer understandings of contaminant transport from the different source areas in the WOC watershed. WAG 2 consists of WOC and its tributaries downstream of the ORNL main plant area, White Oak Lake, the White Oak Creek Embayment of the Clinch River, and the associated flood plains and subsurface environment. The WOC watershed encompasses ORNL and associated WAGs. WAG 2 acts as an integrator for contaminant releases from the contaminated sites at ORNL and as the conduit transporting contaminants to the Clinch River. The main objectives of the Seep Task were to identify and characterize seeps, tributaries and source areas that are responsible for the contaminant releases to the main streams in WAG 2 and to quantify their input to the total contaminant release from the watershed at White Oak Dam (WOD). Efforts focused on 90 Sr, 3 H, and 137 Cs because these contaminants pose the greatest potential human health risk from water ingestion at WOD. Bimonthly sampling was conducted throughout the WOC watershed beginning in March 1993 and ending in August 1994. Samples were also collected for metals, anions, alkalinity, organics, and other radionuclides

Shell growth and environmental control of methanophyllic Thyasirid bivalves from Svalbard cold seeps

Science.gov (United States)

Carroll, Michael; Åström, Emmelie; Ambrose, William; Locke, William; Oliver, Graham; Hong, Wei-Li; Carroll, JoLynn

2016-04-01

The analysis of molluscan shell material (sclerochronology) can provide information about an organism's age, growth history, and environmental conditions during its lifetime. Bivalve molluscs are common members of hydrothermal vents and methane cold seeps communities where, supported by chemosynthetic symbionts, they can reach high density and biomass. But little is known about methane-associated bivalve populations inhabiting high-Arctic cold seeps, and sclerochronological analysis of methane-influenced bivalves is rare. We measured growth rates and elemental and isotopic shell signatures in a newly discovered species of bivalve (Thyasiridae) from cold seeps at 350-390m depth southwest of Svalbard. First discovered in 2014, recently described shells of Thyasira capitanea sp.nov. were found at 2 independent seep systems in Storfjordrenna. Mean shell carbon isotopic ratios from inorganic δ13C (mean = -4.8‰) and organic δ13C (mean = -26.9‰) fractions clearly indicate a methane influenced habitat and food source for these organisms. Shell mineral ratios (Li/Ca, Mg/Ca, Mn/Ca, Fe/Ca, Sr/Ca, Ba/Ca, Pb/Ca) sampled along the axis of growth with laser-ablated ICP-MS exhibit variability through time and between sites, suggesting that concentrations of these elements that may be affected by methane emissions. The mineralogical data also elucidates the internal pattern of shell deposition and growth checks, and combined with the isotopic and growth rate data, enables us to interpret the temporal history of methane release from these locations.

Methane seep in shallow-water permeable sediment harbors high diversity of anaerobic methanotrophic communities, Elba, Italy

Directory of Open Access Journals (Sweden)

S Emil Ruff

2016-03-01

Full Text Available The anaerobic oxidation of methane (AOM is a key biogeochemical process regulating methane emission from marine sediments into the hydrosphere. AOM is largely mediated by consortia of anaerobic methanotrophic archaea (ANME and sulfate-reducing bacteria (SRB, and has mainly been investigated in deep-sea sediments. Here we studied methane seepage at four spots located at 12 m water depth in coastal, organic-carbon depleted permeable sands off the Island of Elba (Italy. We combined biogeochemical measurements, sequencing-based community analyses and in situ hybridization to investigate the microbial communities of this environment. Increased alkalinity, formation of free sulfide and nearly stoichiometric methane oxidation and sulfate reduction rates up to 200 nmol g-1 day-1 indicated the predominance of sulfate-coupled AOM. With up to 40 cm thickness the zones of AOM activity were unusually large and occurred in deeper sediment horizons (20–50 cm below seafloor as compared to diffusion-dominated deep-sea seeps, which is likely caused by advective flow of pore water due to the shallow water depth and permeability of the sands. Hydrodynamic forces also may be responsible for the substantial phylogenetic and unprecedented morphological diversity of AOM consortia inhabiting these sands, including the clades ANME-1a/b, ANME-2a/b/c, ANME-3 and their partner bacteria SEEP-SRB1a and SEEP-SRB2. High microbial dispersal, the availability of diverse energy sources and high habitat heterogeneity might explain that the emission spots shared few microbial taxa, despite their physical proximity. Although the biogeochemistry of this shallow methane seep was very different to that of deep-sea seeps, their key functional taxa were very closely related, which supports the global dispersal of key taxa and underlines strong selection by methane as the predominant energy source. Mesophilic, methane-fueled ecosystems in shallow-water permeable sediments may comprise

A New Global Open Source Marine Hydrocarbon Emission Site Database

Science.gov (United States)

Onyia, E., Jr.; Wood, W. T.; Barnard, A.; Dada, T.; Qazzaz, M.; Lee, T. R.; Herrera, E.; Sager, W.

2017-12-01

Hydrocarbon emission sites (e.g. seeps) discharge large volumes of fluids and gases into the oceans that are not only important for biogeochemical budgets, but also support abundant chemosynthetic communities. Documenting the locations of modern emissions is a first step towards understanding and monitoring how they affect the global state of the seafloor and oceans. Currently, no global open source (i.e. non-proprietry) detailed maps of emissions sites are available. As a solution, we have created a database that is housed within an Excel spreadsheet and use the latest versions of Earthpoint and Google Earth for position coordinate conversions and data mapping, respectively. To date, approximately 1,000 data points have been collected from referenceable sources across the globe, and we are continualy expanding the dataset. Due to the variety of spatial extents encountered, to identify each site we used two different methods: 1) point (x, y, z) locations for individual sites and; 2) delineation of areas where sites are clustered. Certain well-known areas, such as the Gulf of Mexico and the Mediterranean Sea, have a greater abundance of information; whereas significantly less information is available in other regions due to the absence of emission sites, lack of data, or because the existing data is proprietary. Although the geographical extent of the data is currently restricted to regions where the most data is publicly available, as the database matures, we expect to have more complete coverage of the world's oceans. This database is an information resource that consolidates and organizes the existing literature on hydrocarbons released into the marine environment, thereby providing a comprehensive reference for future work. We expect that the availability of seafloor hydrocarbon emission maps will benefit scientific understanding of hydrocarbon rich areas as well as potentially aiding hydrocarbon exploration and environmental impact assessements.

Interpretative approaches to identifying sources of hydrocarbons in complex contaminated environments

International Nuclear Information System (INIS)

Sauer, T.C.; Brown, J.S.; Boehm, P.D.

1993-01-01

Recent advances in analytical instrumental hardware and software have permitted the use of more sophisticated approaches in identifying or fingerprinting sources of hydrocarbons in complex matrix environments. In natural resource damage assessments and contaminated site investigations of both terrestrial and aquatic environments, chemical fingerprinting has become an important interpretative tool. The alkyl homologues of the major polycyclic and heterocyclic aromatic hydrocarbons (e.g., phenanthrenes/anthracenes, dibenzothiophenes, chrysenes) have been found to the most valuable hydrocarbons in differentiating hydrocarbon sources, but there are other hydrocarbon analytes, such as the chemical biomarkers steranes and triterpanes, and alkyl homologues of benzene, and chemical methodologies, such as scanning UV fluorescence, that have been found to be useful in certain environments. This presentation will focus on recent data interpretative approaches for hydrocarbon source identification assessments. Selection of appropriate targets analytes and data quality requirements will be discussed and example cases including the Arabian Gulf War oil spill results will be presented

Dynamics of rainwater lenses on upward seeping saline groundwater

NARCIS (Netherlands)

Eeman, Sara

2017-01-01

Fresh water is generally a limited resource in coastal areas which are often densely populated. In low-lying areas, groundwater is mostly saline and both agriculture and freshwater nature depend on a thin lens of rainwater that is formed by precipitation surplus on top of saline, upward seeping

Interaction between hydrocarbon seepage, chemosynthetic communities, and bottom water redox at cold seeps of the Makran accretionary prism: insights from habitat-specific pore water sampling and modeling

Directory of Open Access Journals (Sweden)

D. Fischer

2012-06-01

Full Text Available The interaction between fluid seepage, bottom water redox, and chemosynthetic communities was studied at cold seeps across one of the world's largest oxygen minimum zones (OMZ located at the Makran convergent continental margin. Push cores were obtained from seeps within and below the core-OMZ with a remotely operated vehicle. Extracted sediment pore water was analyzed for sulfide and sulfate concentrations. Depending on oxygen availability in the bottom water, seeps were either colonized by microbial mats or by mats and macrofauna. The latter, including ampharetid polychaetes and vesicomyid clams, occurred in distinct benthic habitats, which were arranged in a concentric fashion around gas orifices. At most sites colonized by microbial mats, hydrogen sulfide was exported into the bottom water. Where macrofauna was widely abundant, hydrogen sulfide was retained within the sediment.

Numerical modeling of pore water profiles was performed in order to assess rates of fluid advection and bioirrigation. While the magnitude of upward fluid flow decreased from 11 cm yr⁻¹ to <1 cm yr⁻¹ and the sulfate/methane transition (SMT deepened with increasing distance from the central gas orifice, the fluxes of sulfate into the SMT did not significantly differ (6.6–9.3 mol m⁻² yr⁻¹. Depth-integrated rates of bioirrigation increased from 120 cm yr⁻¹ in the central habitat, characterized by microbial mats and sparse macrofauna, to 297 cm yr⁻¹ in the habitat of large and few small vesicomyid clams. These results reveal that chemosynthetic macrofauna inhabiting the outer seep habitats below the core-OMZ efficiently bioirrigate and thus transport sulfate down into the upper 10 to 15 cm of the sediment. In this way the animals deal with the lower upward flux of methane in outer habitats by stimulating rates of anaerobic oxidation of methane (AOM with sulfate high enough to provide

Biodiversity on the Rocks: Macrofauna Inhabiting Authigenic Carbonate at Costa Rica Methane Seeps.

Directory of Open Access Journals (Sweden)

Lisa A Levin

Full Text Available Carbonate communities: The activity of anaerobic methane oxidizing microbes facilitates precipitation of vast quantities of authigenic carbonate at methane seeps. Here we demonstrate the significant role of carbonate rocks in promoting diversity by providing unique habitat and food resources for macrofaunal assemblages at seeps on the Costa Rica margin (400-1850 m. The attendant fauna is surprisingly similar to that in rocky intertidal shores, with numerous grazing gastropods (limpets and snails as dominant taxa. However, the community feeds upon seep-associated microbes. Macrofaunal density, composition, and diversity on carbonates vary as a function of seepage activity, biogenic habitat and location. The macrofaunal community of carbonates at non-seeping (inactive sites is strongly related to the hydrography (depth, temperature, O2 of overlying water, whereas the fauna at sites of active seepage is not. Densities are highest on active rocks from tubeworm bushes and mussel beds, particularly at the Mound 12 location (1000 m. Species diversity is higher on rocks exposed to active seepage, with multiple species of gastropods and polychaetes dominant, while crustaceans, cnidarians, and ophiuroids were better represented on rocks at inactive sites. Macro-infauna (larger than 0.3 mm from tube cores taken in nearby seep sediments at comparable depths exhibited densities similar to those on carbonate rocks, but had lower diversity and different taxonomic composition. Seep sediments had higher densities of ampharetid, dorvilleid, hesionid, cirratulid and lacydoniid polychaetes, whereas carbonates had more gastropods, as well as syllid, chrysopetalid and polynoid polychaetes. Stable isotope signatures and metrics: The stable isotope signatures of carbonates were heterogeneous, as were the food sources and nutrition used by the animals. Carbonate δ13Cinorg values (mean = -26.98‰ ranged from -53.3‰ to +10.0‰, and were significantly heavier than

Parallels between playbacks and Pleistocene tar seeps suggest sociality in an extinct sabretooth cat, Smilodon

OpenAIRE

Carbone, Chris; Maddox, Tom; Funston, Paul J.; Mills, Michael G.L.; Grether, Gregory F.; Van Valkenburgh, Blaire

2008-01-01

Inferences concerning the lives of extinct animals are difficult to obtain from the fossil record. Here we present a novel approach to the study of extinct carnivores, using a comparison between fossil records (n=3324) found in Late Pleistocene tar seeps at Rancho La Brea in North America and counts (n=4491) from playback experiments used to estimate carnivore abundance in Africa. Playbacks and tar seep deposits represent competitive, potentially dangerous encounters where multiple predators ...

A 1.4-Billion Pixel Map of the Seafloor: BOEM's Mission to Visualize Dynamic Geology and Identify Natural Seep Sites in the Gulf of Mexico

Science.gov (United States)

Kramer, K.; Shedd, W. W.

2017-12-01

In May, 2017, the U.S. Department of the Interior's Bureau of Ocean Energy Management (BOEM) published a high-resolution seafloor map of the northern Gulf of Mexico region. The new map, derived from 3-D seismic surveys, provides the scientific community with enhanced resolution and reveals previously undiscovered and poorly resolved geologic features of the continental slope, salt minibasin province, abyssal plain, Mississippi Fan, and the Florida Shelf and Escarpment. It becomes an even more powerful scientific tool when paired with BOEM's public database of 35,000 seafloor features, identifying natural hydrocarbon seeps, hard grounds, mud volcanoes, sediment flows, pockmarks, slumps, and many others. BOEM has mapped the Gulf of Mexico seafloor since 1998 in a regulatory mission to identify natural oil and gas seeps and protect the coral and chemosynthetic communities growing at those sites. The nineteen-year mapping effort, still ongoing, resulted in the creation of the 1.4-billion pixel map and the seafloor features database. With these tools and continual collaboration with academia, professional scientific institutions, and the offshore energy industry, BOEM will continue to incorporate new data to update and expand these two resources on a regular basis. They can be downloaded for free from BOEM's website at https://www.boem.gov/Gulf-of-Mexico-Deepwater-Bathymetry/ and https://www.boem.gov/Seismic-Water-Bottom-Anomalies-Map-Gallery/.

Aliphatic hydrocarbons and triterpenes of the Congo deep-sea fan

Science.gov (United States)

Méjanelle, Laurence; Rivière, Béatrice; Pinturier, Laurence; Khripounoff, Alexis; Baudin, François; Dachs, Jordi

2017-08-01

Hydrocarbons were analyzed in sediments from the Congo River deep-sea fan, from the Congo River, and in sinking particles collected by sediment traps 40 m above the sediment. Studied sites encompassed three lobes of decreasing age of formation along the canyon: sites A, F and C and a another lobe system, disconnected from the active channel since 4 ka, Site E. Terrestrial long-chain odd n-alkanes were dominant in all sediments of the lobe system. Unsaturated terpenoids sourced by higher plants, such as gammacerene, lupene, ursene and oleanene, were also detected. At site C, characterized by high accumulation rates (10-20 cm yr-1), the organic matter spends less time in the oxic layer than at other sites and high phytadiene concentrations 10-17 μg gOC-1) evidenced recent terrestrial and phytoplanktonic remains reworked in anaerobic conditions. In these sediments, organic carbon-normalized concentrations of terrestrial alkanes and terpenoids were several fold higher than in the lobe sediments with lower accumulation rates (sites A and F), arguing for a more rapid degradation of terrestrial hydrocarbons than bulk organic carbon in the first steps of pre-diagenesis. Ample variations in the contributions of biomarkers from higher plants, ferns, bacteria and angiosperms, indicate an heterogeneous contribution of the soil and vegetation detritus delivered to the Congo lobe sediments. Lower concentrations in terrestrial hydrocarbons at site E, 45 km away from the active canyon, indicated that river particles are still admixed to the dominant marine organic matter. Diploptene and hop-7(21)-ene have a dual origin, from terrestrial and marine microorganisms. Scatter in their relationship to gammacerene argues for a contribution of marine microorganisms, in addition to soils-sourced microorganisms. The close distribution patterns of diploptene, hop-21-ene, hop-7(21)ene and neohop-13(18)-ene is in line with the hypothesis of sequential clay-catalyzed isomerisation of bacterial

Transport and transfer rates in the waters of the continental shelf and slope: SEEP

International Nuclear Information System (INIS)

Biscaye, P.E.; Anderson, R.F.

1993-01-01

The overall Shelf Edge Exchange Processes (SEEP) Program, which began in 1980 or 1981, had as its goal the testing of a hypothesis with respect to the fate of particulate matter formed in and introduced into the waters of the continental shelf adjacent to the northern east coast of the US, i.e., the MAB. The original hypothesis was that a large proportion of the particles in general, and of the particulate organic carbon (POC) in particular, was exported from the shelf, across the shelf/slope break and front, into the waters of, and, to some degree, deposited in the sediments of the continental slope. This hypothesis was based on budgets of organic carbon and lead-210 that did not account for a large proportion of those species in the waters or sediments of the shelf, and on a carbon-rich band of sediments centered on the slope at ∼1,000 m water depth. The results of the first SEEP experiment, south of New England and Long Island (SEEP-1) suggested, but did not prove, that there was only a relatively small proportion of the carbon which was exported from the shelf to the slope. The objective of the second experiment -- SEEP-2 -- done under the subject grant, was to tighten the experiment in terms of the kinds of data collected, and to focus it more on the shelf and only the upper slope, where shelf-derived particles were thought to be deposited

Impact of protists on a hydrocarbon-degrading bacterial community from deep-sea Gulf of Mexico sediments: A microcosm study

Science.gov (United States)

Beaudoin, David J.; Carmichael, Catherine A.; Nelson, Robert K.; Reddy, Christopher M.; Teske, Andreas P.; Edgcomb, Virginia P.

2016-07-01

In spite of significant advancements towards understanding the dynamics of petroleum hydrocarbon degrading microbial consortia, the impacts (direct or indirect via grazing activities) of bacterivorous protists remain largely unknown. Microcosm experiments were used to examine whether protistan grazing affects the petroleum hydrocarbon degradation capacity of a deep-sea sediment microbial community from an active Gulf of Mexico cold seep. Differences in n-alkane content between native sediment microcosms and those treated with inhibitors of eukaryotes were assessed by comprehensive two-dimensional gas chromatography following 30-90 day incubations and analysis of shifts in microbial community composition using small subunit ribosomal RNA gene clone libraries. More biodegradation was observed in microcosms supplemented with eukaryotic inhibitors. SSU rRNA gene clone libraries from oil-amended treatments revealed an increase in the number of proteobacterial clones (particularly γ-proteobacteria) after spiking sediments with diesel oil. Bacterial community composition shifted, and degradation rates increased, in treatments where protists were inhibited, suggesting protists affect the hydrocarbon degrading capacity of microbial communities in sediments collected at this Gulf of Mexico site.

Physical basis of coastal productivity: The SEEP and MASAR experiments

Science.gov (United States)

Csanady, G. T.

Two major cooperative experiments, code-named Shelf Edge Exchange Processes (SEEP) I and II, were carried out on the northeast U.S. continental shelf and slope by an interdisciplinary group of scientists in the past decade. The work, supported by the Department of Energy, Office of Health and Environmental Research, had the broad aim of determining whether or to what extent energy-related human activities interfere with the high biological productivity of coastal waters. Much of SEEP I work was reported in a dedicated issue of Continental Shelf Research, including a summary article on the experiment as a whole [Walsh et al., 1988[. A parallel experiment, supported by the Minerals Management Service and code-named Mid Atlantic Slope and Rise (MASAR), had the objective of exploring physical processes over the continental slope and rise, including especially currents in the upper part of the water column. A good deal of MASAR work was also reported in the SEEP issue just mentioned, mainly in an article by Csanady and Hamilton (1988). There have been other papers and publications on these experiments, and more are forthcoming. While many questions remain, our horizons have broadened considerably after a decade of work on this problem, as if our aeroplane had just emerged from clouds to expose an interesting landscape. In this article I shall try to describe the physical (-oceanographic) features of that landscape, not in the chronological order in which we have espied them, but as the logic of the subject dictates.

Assessment of soil-gas, seep, and soil contamination at the North Range Road Landfill, Fort Gordon, Georgia, 2008-2009

Science.gov (United States)

Landmeyer, James E.; Falls, W. Fred; Ratliff, W. Hagan; Wellborn, John B.

2011-01-01

Soil gas, seeps, and soil were assessed for contaminants at the North Range Road Landfill at Fort Gordon, Georgia, from October 2008 to September 2009. The assessment included delineating organic contaminants present in soil-gas samples beneath the area estimated to be the landfill and in water samples collected from three seeps at the base of the landfill. Inorganic contaminants were determined in three seep samples and in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process.

The vertical distribution of prokaryotes in the surface sediment of Jiaolong cold seep at the northern South China Sea.

Science.gov (United States)

Wu, Yuzhi; Qiu, Jian-Wen; Qian, Pei-Yuan; Wang, Yong

2018-05-01

In deep-sea cold seeps, microbial communities are shaped by geochemical components in seepage solutions. In the present study, we report the composition of microbial communities and potential metabolic activities in the surface sediment of Jiaolong cold seep at the northern South China Sea. Pyrosequencing of 16S rRNA gene amplicons revealed that a majority of the microbial inhabitants of the surface layers (0-6 cm) were sulfur oxidizer bacteria Sulfurimonas and archaeal methane consumer ANME-1, while sulfate reducer bacteria SEEP-SRB1, ANME-1 and ANME-2 dominated the bottom layers (8-14 cm). The potential ecological roles of the microorganisms were further supported by the presence of functional genes for methane oxidation, sulfur oxidation, sulfur reduction and nitrate reduction in the metagenomes. Metagenomic analysis revealed a significant correlation between coverage of 16S rRNA gene of sulfur oxidizer bacteria, functional genes involved in sulfur oxidation and nitrate reduction in different layers, indicating that sulfur oxidizing may be coupled to nitrate reducing at the surface layers of Jiaolong seeping site. This is probably related to the sulfur oxidizers of Sulfurimonas and Sulfurovum, which may be the capacity of nitrate reduction or associated with unidentified syntrophic nitrate-reducing microbes in the surface of the cold seep.

Chemosynthetic trophic support for the benthic community at an intertidal cold seep site at Mocha Island off central Chile

Science.gov (United States)

Sellanes, Javier; Zapata-Hernández, Germán; Pantoja, Silvio; Jessen, Gerdhard L.

2011-12-01

We analyzed C and N stable isotope ratios of benthic fauna and their potential food sources at an intertidal methane seep site and a control site without emanation at Mocha Island (central Chile). The objective was to trace the origin of the main food sources used by the local heterotrophic fauna, based on the hypothesis that chemosynthetic production could be partially fueling the local food web at the seep site. Food sources sampled at both sites included macroalgae, particulate organic matter and bacteria-like filaments found growing over the red algae Gelidium lingulatum within the areas of active methane release. At the control site, located 11 km away from the gas emanation, fauna exhibited moderate δ 13C values ranging from -16.2‰ (in a nereid polychaete) to -14.8‰ (in a cirolanid isopod), which were consistent with those of the potential photosynthetic food sources sampled at this site (-20.2 to -16.5‰). δ 13C values of the photosynthetic food sources at the seep site similarly ranged between -25.4 and -17.9‰. However, a portion of the animals at this site were consistently more 13C-depleted, with δ 13C values close to that of the seeping methane (-43.8‰) and the bacteria-like filaments (-39.2 ± 2.5‰) also collected at this site. Specific examples were the Marphysa sp. polychaetes (δ 13C = -44.7 ± 0.6‰), the Schistomeringos sp. dorvilleid polychaetes (δ 13C = -42.9‰), and the tanaid crustacean Zeuxo marmoratus (δ 13C = -37.3 ± 0.2‰). The significantly higher δ 13C values of the herbivorous gastropod Tegula atra at the seep site (-29.3 ± 3.1‰) than at the control site (-12.6 ± 0.3‰) also indicated differences among sites of the preferred carbon sources of this species. Mixing model estimates indicate that at the seep site bacteria-like filaments could be contributing up to ˜60% of the assimilated diet of selected invertebrates. Furthermore, several indicators of trophic structure, based in isotopic niche metrics, indicate a

Detection of radiation-induced hydrocarbons in irradiated fish and prawns by means of on-line coupled liquid chromatography-gas chromatography

International Nuclear Information System (INIS)

Schulzki, G.; Spiegelberg, A.; Bogl, K.W.; Schreiberg, G.A.

1997-01-01

Radiation-induced hydrocarbons were analyzed in a fatty (halibut) and a lean fish (cod) as well as in a prawn species by on-line coupled liquid chromatography (LC) -gas chromatography (GC) combined with mass spectrometry. In irradiated halibut which is known to contain mainly saturated and monounsaturated fatty acids, all expected radiolytic alkanes, alkenes, and alkadienes could be detected. The yields of the C(n-1) and C(n-2:1) hydrocarbons were comparable to those found in irradiated lipids of terrestrial animals and plants. However, in cod and prawns which contain high levels of polyunsaturated fatty acids (PUFA), the C(n-1) hydrocarbons were found in concentrations which were up to 10 times higher whereas the C(n-2:1) products were again comparable to those of terrestrial animals and plants. The identification of radiation-induced hydrocarbons in fish lipids was achieved by transfer of the hydrocarbons from the LC column to the gas chromatographic column in fractions differing in their degree of unsaturation. For the first time, radiation-induced hydrocarbons with more than four double bonds generated from polyunsaturated fatty acids (20:4 omega 6 and 20:5 omega 3) could be identified

Population genetic structure in Sabatieria (Nematoda) reveals intermediary gene flow and admixture between distant cold seeps from the Mediterranean Sea.

Science.gov (United States)

De Groote, Annelies; Hauquier, Freija; Vanreusel, Ann; Derycke, Sofie

2017-07-01

There is a general lack of information on the dispersal and genetic structuring for populations of small-sized deep-water taxa, including free-living nematodes which inhabit and dominate the seafloor sediments. This is also true for unique and scattered deep-sea habitats such as cold seeps. Given the limited dispersal capacity of marine nematodes, genetic differentiation between such geographically isolated habitat patches is expected to be high. Against this background, we examined genetic variation in both mitochondrial (COI) and nuclear (18S and 28S ribosomal) DNA markers of 333 individuals of the genus Sabatieria, abundantly present in reduced cold-seep sediments. Samples originated from four Eastern Mediterranean cold seeps, separated by hundreds of kilometers, and one seep in the Southeast Atlantic. Individuals from the Mediterranean and Atlantic were divided into two separate but closely-related species clades. Within the Eastern Mediterranean, all specimens belonged to a single species, but with a strong population genetic structure (Φ ST  = 0.149). The haplotype network of COI contained 19 haplotypes with the most abundant haplotype (52% of the specimens) shared between all four seeps. The number of private haplotypes was high (15), but the number of mutations between haplotypes was low (1-8). These results indicate intermediary gene flow among the Mediterranean Sabatieria populations with no evidence of long-term barriers to gene flow. The presence of shared haplotypes and multiple admixture events indicate that Sabatieria populations from disjunct cold seeps are not completely isolated, with gene flow most likely facilitated through water current transportation of individuals and/or eggs. Genetic structure and molecular diversity indices are comparable to those of epiphytic shallow-water marine nematodes, while no evidence of sympatric cryptic species was found for the cold-seep Sabatieria.

Management of Herbaceous Seeps and Wet Savannas for Threatened and Endangered Species

National Research Council Canada - National Science Library

Harper, Mary

1998-01-01

Wetland communities such as herbaceous seeps and wet savannas occur on military installations throughout the southeastern United States, usually as pockets of wet habitat within a matrix of drier longleaf pine woodlands...

Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: Concentrations, composition, and associated risks to protected sea otters

International Nuclear Information System (INIS)

Harris, Kate A.; Yunker, Mark B.; Dangerfield, Neil; Ross, Peter S.

2011-01-01

Sediment-associated hydrocarbons can pose a risk to wildlife that rely on benthic marine food webs. We measured hydrocarbons in sediments from the habitat of protected sea otters in coastal British Columbia, Canada. Alkane concentrations were dominated by higher odd-chain n-alkanes at all sites, indicating terrestrial plant inputs. While remote sites were dominated by petrogenic polycyclic aromatic hydrocarbons (PAHs), small harbour sites within sea otter habitat and sites from an urban reference area reflected weathered petroleum and biomass and fossil fuel combustion. The partitioning of hydrocarbons between sediments and adjacent food webs provides an important exposure route for sea otters, as they consume ∼25% of their body weight per day in benthic invertebrates. Thus, exceedences of PAH sediment quality guidelines designed to protect aquatic biota at 20% of the sites in sea otter habitat suggest that sea otters are vulnerable to hydrocarbon contamination even in the absence of catastrophic oil spills. - Highlights: → Sediment hydrocarbon signatures differed between remote and impacted coastal sites. → A natural background comprised terrestrial plant alkanes and petrogenic PAHs. → Impacted sites reflected a history of petrogenic and pyrogenic hydrocarbon inputs. → Hydrocarbons at some sites exceeded guidelines for the protection of aquatic life. → Protected sea otters may thus be at risk as they rely primarily on benthic prey. - Anthropogenically-derived hydrocarbons in coastal sediments in British Columbia may pose a risk to protected sea otters.

How Specific Microbial Communities Benefit the Oil Industry: Dynamics of Alcanivorax spp. in Oil-Contaminated Intertidal Beach Sediments Undergoing Bioremediation

Science.gov (United States)

Singh, Arvind K.; Sherry, Angela; Gray, Neil D.; Jones, Martin D.; Röling, Wilfred F. M.; Head, Ian M.

The industrial revolution has led to significant increases in the consumption of petroleum hydrocarbons. Concomitant with this increase, hydrocarbon pollution has become a global problem resulting from emissions related to operational use, releases during production, pipeline failures and tanker spills. Importantly, in addition to these anthropogenic sources of hydrocarbon pollution, natural seeps alone account for about 50% of total petroleum hydrocarbon releases in the aquatic environment (National Research Council, 2003). The annual input from natural seeps would form a layer of hydrocarbons 20 molecules thick on the sea surface globally if it remained un-degraded (Prince, 2005). By contrast with natural seeps, many oil spills, e.g. Sea Empress (Milford Haven, UK), Prestige (Galicia, Spain), EXXON Valdez (Prince William Sound, Alaska, USA), released huge amounts of oil (thousands to hundreds of thousand tonnes; Table 24.1) in a locally confined area over a short period of time with a huge acute impact on the marine environment. These incidents have attracted the attention of both the general public and the scientific community due to their great impact on coastal ecosystems. Although many petroleum hydrocarbons are toxic, they are degraded by microbial consortia naturally present in marine ecosystems.

Carbon Composition of Particulate Organic Carbon in the Gulf of Mexico

Science.gov (United States)

Rogers, K.; Montoya, J. P.; Weber, S.; Bosman, S.; Chanton, J.

2016-02-01

The Deepwater Horizon blowout released 5.0x1011 g C from gaseous hydrocarbons and up to 6.0x1011g C from oil into the water column. Another carbon source, adding daily to the water column, leaks from the natural hydrocarbon seeps that pepper the seafloor of the Gulf of Mexico. How much of this carbon from the DWH and natural seeps is assimilated into particulate organic carbon (POC) in the water column? We filtered seawater collected in 2010, 2012, and 2013 from seep and non-seep sites, collecting POC on 0.7µm glass microfiber filters and analyzing the POC for stable and radiocarbon isotopes. Mixing models based on carbon isotopic endmembers of methane, oil, and modern production were used to estimate the percentage of hydrocarbon incorporated into POC. Significant differences were seen between POC from shallow and deep waters and between POC collected from seep, non-seep, and blowout sites; however yearly differences were not as evident suggesting the GOM has a consistent supply of depleted carbon. Stable carbon isotopes signatures of POC in the Gulf averaged -23.7±2.5‰ for shallow samples and -26.65±2.9‰ for deep POC samples, while radiocarbon signatures averaged -100.4±146.1‰ for shallow and -394.6±197‰ for deep samples. POC in the northern Gulf are composed of 23-91% modern carbon, 2-21% methane, and 0-71% oil. Oil plays a major role in the POC composition of the GOM, especially at the natural seep GC600.

Application of Satellite SAR for Discovery and Quantification of Natural Marine Oil Seeps

Science.gov (United States)

Amos, J.; Lai, R.; Zimmer, B.; Leiva, A.; MacDonald, I.

2006-12-01

Natural marine oil seeps discharge gassy drops from the seafloor. Oil drops and gas bubbles reach the surface from water depths as great as 3000m. The oil spreads rapidly, forming an invisible layer that drifts down-wind and down-current in long, linear streaks called slicks. Oil slicks are visible in SAR data because the surfactant dampens capillary waves and reduces backscatter. Application of SAR as an exploration tool in energy prospecting is well-established. We have applied this technique for discovering the chemosynthetic communities that colonize the seafloor in the vicinity of deep-water seeps on the continental margin of the Gulf of Mexico. The management goal for this effort is to prevent harmful impact to these communities resulting from exploration or production activities. The scientific goals are to delineate the zoogeography of the chemosynthetic fauna, which is widespread on continental margins, and to establish study sites where their life history can be investigated. In the course of an ongoing, multidisciplinary study in the spring and summer of 2006, we explored 20 possible sites where SAR and geophysical data indicated seeps might occur. SAR was only partly diagnostic: all sites with SAR-detected slicks were found to have biologic communities, but communities were also found at geophysical anomalies that did not produce slicks. We acquired over 60 RADARSAT SAR images from the northern Gulf of Mexico in cooperation with the Alaska Satellite Facility. The ship RV ATLANTIS was at sea during the acquisition and collected synoptic weather and oceanographic data. To automate interpretation of large image dataset we have employed texture recognition with use of a library of textons applied iteratively to the images. This treatment shows promise in distinguishing floating oil from false targets generated by rain fronts and other phenomena. One goal of the analysis is to delineate bounding boxes to quantify the ocean area covered by the thin oil layer

Changing composition of microbial communities indicates seepage fluid difference of the Thuwal Seeps in the Red Sea

KAUST Repository

Yang, Bo

2015-06-10

© Springer International Publishing Switzerland 2015. Cold seeps are unique ecosystems that are generally characterized by high salinity and reducing solutions. Seepage fluid, the major water influx of this system, contains hypersaline water, sediment pore water, and other components. The Thuwal cold seeps were recently discovered on the continental margin of the Red Sea. Using 16S rRNA gene pyro-sequencing technology, microbial communities were investigated by comparing samples collected in 2011 and 2013. The results revealed differences in the microbial communities between the two sampling times. In particular, a significantly higher abundance of Marine Group I (MGI) Thaumarchaeota was coupled with lower salinity in 2013. In the brine pool, the dominance of Desulfobacterales in 2011 was supplanted byMGI Thaumarchaeota in 2013, perhaps due to a reduced supply of hydrogen sulfide from the seepage fluid. Collectively, this study revealed a difference in water components in this ecosystem between two sampling times. The results indicated that the seawater in this cold seep displayed a greater number of characteristics of normal seawater in 2013 than in 2011, which might represent the dominant driving force for changes in microbial community structures. This is the first study to provide a temporal comparison of the microbial biodiversity of a cold seep ecosystem in the Red Sea.

Changing composition of microbial communities indicates seepage fluid difference of the Thuwal Seeps in the Red Sea

KAUST Repository

Yang, Bo; Zhang, Weipeng; Tian, Renmao; Wang, Yong; Qian, Pei-Yuan

2015-01-01

© Springer International Publishing Switzerland 2015. Cold seeps are unique ecosystems that are generally characterized by high salinity and reducing solutions. Seepage fluid, the major water influx of this system, contains hypersaline water, sediment pore water, and other components. The Thuwal cold seeps were recently discovered on the continental margin of the Red Sea. Using 16S rRNA gene pyro-sequencing technology, microbial communities were investigated by comparing samples collected in 2011 and 2013. The results revealed differences in the microbial communities between the two sampling times. In particular, a significantly higher abundance of Marine Group I (MGI) Thaumarchaeota was coupled with lower salinity in 2013. In the brine pool, the dominance of Desulfobacterales in 2011 was supplanted byMGI Thaumarchaeota in 2013, perhaps due to a reduced supply of hydrogen sulfide from the seepage fluid. Collectively, this study revealed a difference in water components in this ecosystem between two sampling times. The results indicated that the seawater in this cold seep displayed a greater number of characteristics of normal seawater in 2013 than in 2011, which might represent the dominant driving force for changes in microbial community structures. This is the first study to provide a temporal comparison of the microbial biodiversity of a cold seep ecosystem in the Red Sea.

Chemical and isotopic signature of bulk organic matter and hydrocarbon biomarkers within mid-slope accretionary sediments of the northern Cascadia margin gas hydrate system

Science.gov (United States)

Kaneko, Masanori; Shingai, Hiroshi; Pohlman, John W.; Naraoka, Hiroshi

2010-01-01

The chemical and isotopic compositions of sedimentary organic matter (SOM) from two mid-slope sites of the northern Cascadia margin were investigated during Integrated Ocean Drilling Program (IODP) Expedition 311 to elucidate the organic matter origins and identify potential microbial contributions to SOM. Gas hydrate is present at both locations (IODP Sites U1327 and U1328), with distinct patterns of near-seafloor structural accumulations at the cold seep Site U1328 and deeper stratigraphic accumulations at the slope-basin Site U1327. Source characterization and evidence that some components of the organic matter have been diagenetically altered are determined from the concentrations and isotopic compositions of hydrocarbon biomarkers, total organic carbon (TOC), total nitrogen (TN) and total sulfur (TS). The carbon isotopic compositions of TOC (δ13CTOC = −26 to −22‰) and long-chain n-alkanes (C27, C29 and C31, δ13C = −34 to − 29‰) suggest the organic matter at both sites is a mixture of 1) terrestrial plants that employ the C3 photosynthetic pathway and 2) marine algae. In contrast, the δ15NTN values of the bulk sediment (+ 4 to + 8‰) are consistent with a predominantly marine source, but these values most likely have been modified during microbial organic matter degradation. The δ13C values of archaeal biomarker pentamethylicosane (PMI) (− 46.4‰) and bacterial-sourced hopenes, diploptene and hop-21-ene (− 40.9 to − 34.7‰) indicate a partial contribution from methane carbon or a chemoautotrophic pathway. Our multi-isotope and biomarker-based conclusions are consistent with previous studies, based only on the elemental composition of bulk sediments, that suggested a mixed marine-terrestrial organic matter origin for these mid-slope sites of the northern Cascadia margin.

Tubeworm May Live Longer by Cycling Its Sulfur Downward

OpenAIRE

Cordes, Erik E; Arthur, Michael A; Shea, Katriona; Arvidson, Rolf S; Fisher, Charles R

2005-01-01

The deep-sea vestimentiferan tubeworm Lamellibrachia luymesi forms large aggregations at hydrocarbon seeps in the Gulf of Mexico that may persist for over 250 y. Here, we present the results of a diagenetic model in which tubeworm aggregation persistence is achieved through augmentation of the supply of sulfate to hydrocarbon seep sediments. In the model, L. luymesi releases the sulfate generated by its internal, chemoautotrophic, sulfide-oxidizing symbionts through posterior root-like extens...

Characterization of light gaseous hydrocarbons of the surface soils of Krishna-Godavari basin, India.

Science.gov (United States)

Lakshmi, M; Rasheed, M A; Madhavi, T; Kalpana, M S; Patil, D J; Dayal, A M

2012-01-01

Several techniques are used for the exploration of hydrocarbons, of which; the geochemical techniques involving the microbiological technique use the principle of detecting the light hydrocarbon seepage activities for indication of sub-surface petroleum accumulations. Asurvey was carried out to characterize the light gaseous hydrocarbons seeping in oil and gas fields of Krishna-Godavari basin ofAndhra Pradesh. Aset of 50 sub-soil samples were collected at depths of about 3 m for geochemical analyses and 1m for microbiological analysis. The microbial prospecting studies showed the presence of high bacterial population for methane 2.5 x 10(2) to 6.0 x 10(6) cfu g(-1), propane 1x10(2) to 8.0 x 10(6) cfu g(-1) in soil samples. The adsorbed soil gas analysis showed the presence of moderate to low concentrations of methane (26 to 139 ppb), ethane (0 to 17 ppb), propane (0 to 8 ppb), butane (0 to 5 ppb) and pentane (0 to 2 ppb) in the soil samples of the study area. Carbon isotope analysis for methane ('13C1) ranging from -36.6 to -22.7 per hundred Pee Dee Belemnite (PDB) suggests these gases are of thermogenic origin. Geo-microbial prospecting method coupled with adsorbed soil gas and carbon isotope ratio analysis have thus shown good correlation with existing oil/gas fields of Krishna-Godavari basin.

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

Science.gov (United States)

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.

Boron, lithium and methane isotope composition of hyperalkaline waters (Northern Apennines, Italy): Terrestrial serpentinization or mixing with brine?

International Nuclear Information System (INIS)

Boschetti, Tiziano; Etiope, Giuseppe; Pennisi, Maddalena; Romain, Millot; Toscani, Lorenzo

2013-01-01

Highlights: ► First data on boron and lithium isotope on waters from ophiolites are described. ► High boron and lithium isotope composition may be related to terrestrial serpentinization. ► Methane isotope data show unusual biotic signature. - Abstract: Spring waters issuing from serpentinized ultramafic rocks of the Taro-Ceno Valleys (Northern Apennine, Emilia-Romagna region, Italy) were analyzed for major element, trace element and dissolved gas concentrations and δ 11 B, δ 7 Li, δ 18 O(H 2 O), δ 2 H(H 2 O), δ 13 C(CH 4 ) and δ 2 H(CH 4 ) isotope compositions. Similar to other springs worldwide that issue from serpentinites, the chemical composition of the waters evolves with water–rock interaction from Ca-HCO 3 , through Mg-HCO 3 and ultimately to a hyperalkaline Na-(Ca)-OH composition. Most of the Ca- and Mg-HCO 3 springs have δ 11 B ranging between +16.3‰ and +23.7‰, consistent with the range of low P–T serpentinites. Very high δ 11 B in two springs from Mt. Prinzera (PR10: +39‰; PR01: +43‰) can be related to isotopic fractionation during secondary phase precipitation, as also inferred from δ 7 Li values. In contrast to typical abiogenic isotope signatures of CH 4 from serpentinized rocks, dissolved CH 4 from the Taro-Ceno hyperalkaline springs has an apparent biotic (thermogenic and/or mixed thermogenic-microbial) signature with δ 13 C(CH 4 ) ranging from −57.5‰ to −40.8‰, which is similar to that of hydrocarbons from production wells and natural seeps in adjacent hydrocarbon systems. The data suggest that CH 4 in the hyperalkaline springs investigated in this study may derive from organic matter of the sedimentary (flysch and arenaceous) formations underlying the ophiolite unit. However, small amounts of H 2 were detected in one hyperalkaline spring (PR10), but for two springs with very low CH 4 concentrations (PR01 and UM15) the δ 2 H value could not be measured, so the occurrence of some abiotic CH 4 cannot be excluded

Quantification of seep-related methane gas emissions at Tommeliten, North Sea

NARCIS (Netherlands)

Schneider von Deimling, J.S.; Rehder, G.; Greinert, J.; McGinnnis, D.F.; Boetius, A.; Linke, P.

2011-01-01

Tommeliten is a prominent methane seep area in the Central North Sea. Previous surveys revealed shallow gas-bearing sediments and methane gas ebullition into the water column. In this study, the in situ methane flux at Tommeliten is re-assessed and the potential methane transport to the atmosphere

High-Resolution Seafloor Mapping at A Deep-Sea Methane Seep Field with an Autonomous Underwater Vehicle

Science.gov (United States)

Skarke, A. D.

2017-12-01

A growing body of research indicates that points of seafloor gas emission, known as cold-seeps, are a common feature along many continental margins. Results from recent exploration efforts show that benthic environments at cold-seeps are characterized by extensive authigenic carbonate crusts and complex chemosynthetic communities. The seafloor morphology and geophysical properties of these locations are heterogeneous and relatively complex due to the three-dimensional structure created by carbonate buildups and dense bivalve beds. Seeps are often found clustered and the spatial extent of associated seafloor crusts and beds can reach multiple square kilometers. Here, the results of a 1.25 km2 autonomous underwater vehicle (AUV) survey of a deep-sea methane seep field with 13 vents, at a nominal depth of 1400 m, located near Veatch Canyon on the US Atlantic margin are presented. Multibeam sonar, sidescan sonar, and a sub bottom profiler on the AUV were used to make high-resolution observations of seafloor bathymetry (resolution 1m2) as well as water column, seafloor, and subsurface acoustic backscatter intensity. Additionally, a downward oriented camera was used to collect seafloor imagery coincident with acoustic observations at select locations. Acoustic results indicated the location of discrete gas plumes as well as a continuous area of elevated seafloor roughness and backscatter intensity consistent with the presence of large scale authigenic rock outcrops and extensive mussel beds, which were visually confirmed with camera imagery. Additionally, a linear area of particularly elevated seafloor roughness and acoustic backscatter intensity that lies sub-parallel to an adjacent ridge was interpreted to be controlled by underlying geologic processes such as soft sediment faulting. Automated analysis of camera imagery and coincident acoustic backscatter and bathymetry data as well as derivative metrics (e.g. slope and rugosity) was used to segment and classify bed

Studies of volatiles and organic materials in early terrestrial and present-day outer solar system environments

Science.gov (United States)

Sagan, Carl; Thompson, W. Reid; Chyba, Christopher F.; Khare, B. N.

1991-01-01

A review and partial summary of projects within several areas of research generally involving the origin, distribution, chemistry, and spectral/dielectric properties of volatiles and organic materials in the outer solar system and early terrestrial environments are presented. The major topics covered include: (1) impact delivery of volatiles and organic compounds to the early terrestrial planets; (2) optical constants measurements; (3) spectral classification, chemical processes, and distribution of materials; and (4) radar properties of ice, hydrocarbons, and organic heteropolymers.

Comparative composition, diversity and trophic ecology of sediment macrofauna at vents, seeps and organic falls.

Directory of Open Access Journals (Sweden)

Angelo F Bernardino

Full Text Available Sediments associated with hydrothermal venting, methane seepage and large organic falls such as whale, wood and plant detritus create deep-sea networks of soft-sediment habitats fueled, at least in part, by the oxidation of reduced chemicals. Biological studies at deep-sea vents, seeps and organic falls have looked at macrofaunal taxa, but there has yet to be a systematic comparison of the community-level attributes of sediment macrobenthos in various reducing ecosystems. Here we review key similarities and differences in the sediment-dwelling assemblages of each system with the goals of (1 generating a predictive framework for the exploration and study of newly identified reducing habitats, and (2 identifying taxa and communities that overlap across ecosystems. We show that deep-sea seep, vent and organic-fall sediments are highly heterogeneous. They sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist (heterotrophic and symbiont-associated and background fauna. Community-level comparisons reveal that vent, seep and organic-fall macrofauna are very distinct in terms of composition at the family level, although they share many dominant taxa among these highly sulphidic habitats. Stress gradients are good predictors of macrofaunal diversity at some sites, but habitat heterogeneity and facilitation often modify community structure. The biogeochemical differences across ecosystems and within habitats result in wide differences in organic utilization (i.e., food sources and in the prevalence of chemosynthesis-derived nutrition. In the Pacific, vents, seeps and organic-falls exhibit distinct macrofaunal assemblages at broad-scales contributing to ß diversity. This has important implications for the conservation of reducing ecosystems, which face growing threats from human activities.

The hydraulic connectivity, perennial warming and relationship to seismicity of the Davis-Schrimpf Seep Field, Salton Trough, California from new and recent temperature time-series

Science.gov (United States)

Rao, Amar P.

The Davis-Schrimpf Seep Field is a cluster of about 50 transtension-related geothermal seeps in the Imperial Valley, southeastern California. Five temperature time-series were collected from four features and compared to one another, against prior time-series, and to local seismicity. Loggers placed in separate vents within one seep returned moderate anti-correlation. Vents may selectively clog and unclog. Clogging frequencies explaining the observed level of negative correlation were given. Loggers placed in the same vent produced 87-92% positive correlation. It is therefore likely that the vast majority of temperature data measured with loggers possesses meaningful accuracy. Loggers placed in separate seeps exhibited correlation close to or greater than the statistically significant 60% threshold. I propose two lineaments provide a hydraulic connection between these seeps. Two Mw>3.0 earthquake swarms, including one Mw>4.0 event, within 24 kilometers showed possible linkage with >5 degree Celsius temperature perturbations. Seepage warmed 14.5-36.8 degrees Celsius over 5-7 years.

Bioaccumulation of hydrocarbons derived from terrestrial and anthropogenic sources in the Asian clam, Potamocorbula amurensis, in San Francisco Bay estuary

Science.gov (United States)

Pereira, Wilfred E.; Hostettler, Frances D.; Rapp, John B.

1992-01-01

An assessment was made in Suisun Bay, California, of the distributions of hydrocarbons in estuarine bed and suspended sediments and in the recently introduced asian clam, Potamocorbula amurensis. Sediments and clams were contaminated with hydrocarbons derived from petrogenic and pyrogenic sources. Distributions of alkanes and of hopane and sterane biomarkers in sediments and clams were similar, indicating that petroleum hydrocarbons associated with sediments are bioavailable to Potamocorbula amurensis. Polycyclic aromatic hydrocarbons in the sediments and clams were derived mainly from combustion sources. Potamocorbula amurensis is therefore a useful bioindicator of hydrocarbon contamination, and may be used as a biomonitor of hydrocarbon pollution in San Francisco Bay.

Tracking an oil slick from multiple natural sources, Coal Oil Point, California

International Nuclear Information System (INIS)

Leifer, Ira; Luyendyk, Bruce; Broderick, Kris

2006-01-01

Oil slicks on the ocean surface emitted from natural marine hydrocarbon seeps offshore from Coal Oil Point in the Santa Barbara Channel, California were tracked and sampled over a 2-h period. The objectives were to characterize the seep oil and to track its composition over time using a new sampling device, a catamaran drum sampler (CATDRUMS). The sampler was designed and developed at UCSB. Chromatograms showed that oil originating from an informally named, very active seep area, Shane Seep, primarily evolved during the first hour due to mixing with oil originating from a convergence zone slick surrounding Shane Seep. (author)

Tracking an oil slick from multiple natural sources, Coal Oil Point, California

Energy Technology Data Exchange (ETDEWEB)

Leifer, Ira [Marine Sciences Institute, University of California, Santa Barbara, CA 93106 (United States); Luyendyk, Bruce [Department of Geological Sciences, University of California, Santa Barbara, CA 93106 (United States); Broderick, Kris [Exxon/Mobil Exploration Company, 13401 N. Freeway, Houston, TX 77060 (United States)

2006-06-15

Oil slicks on the ocean surface emitted from natural marine hydrocarbon seeps offshore from Coal Oil Point in the Santa Barbara Channel, California were tracked and sampled over a 2-h period. The objectives were to characterize the seep oil and to track its composition over time using a new sampling device, a catamaran drum sampler (CATDRUMS). The sampler was designed and developed at UCSB. Chromatograms showed that oil originating from an informally named, very active seep area, Shane Seep, primarily evolved during the first hour due to mixing with oil originating from a convergence zone slick surrounding Shane Seep. (author)

Subduction zone earthquake probably triggered submarine hydrocarbon seepage offshore Pakistan

Science.gov (United States)

Fischer, David; José M., Mogollón; Michael, Strasser; Thomas, Pape; Gerhard, Bohrmann; Noemi, Fekete; Volkhard, Spiess; Sabine, Kasten

2014-05-01

Seepage of methane-dominated hydrocarbons is heterogeneous in space and time, and trigger mechanisms of episodic seep events are not well constrained. It is generally found that free hydrocarbon gas entering the local gas hydrate stability field in marine sediments is sequestered in gas hydrates. In this manner, gas hydrates can act as a buffer for carbon transport from the sediment into the ocean. However, the efficiency of gas hydrate-bearing sediments for retaining hydrocarbons may be corrupted: Hypothesized mechanisms include critical gas/fluid pressures beneath gas hydrate-bearing sediments, implying that these are susceptible to mechanical failure and subsequent gas release. Although gas hydrates often occur in seismically active regions, e.g., subduction zones, the role of earthquakes as potential triggers of hydrocarbon transport through gas hydrate-bearing sediments has hardly been explored. Based on a recent publication (Fischer et al., 2013), we present geochemical and transport/reaction-modelling data suggesting a substantial increase in upward gas flux and hydrocarbon emission into the water column following a major earthquake that occurred near the study sites in 1945. Calculating the formation time of authigenic barite enrichments identified in two sediment cores obtained from an anticlinal structure called "Nascent Ridge", we find they formed 38-91 years before sampling, which corresponds well to the time elapsed since the earthquake (62 years). Furthermore, applying a numerical model, we show that the local sulfate/methane transition zone shifted upward by several meters due to the increased methane flux and simulated sulfate profiles very closely match measured ones in a comparable time frame of 50-70 years. We thus propose a causal relation between the earthquake and the amplified gas flux and present reflection seismic data supporting our hypothesis that co-seismic ground shaking induced mechanical fracturing of gas hydrate-bearing sediments

A paradox resolved: Sulfide acquisition by roots of seep tubeworms sustains net chemoautotrophy

Science.gov (United States)

Freytag, John K.; Girguis, Peter R.; Bergquist, Derk C.; Andras, Jason P.; Childress, James J.; Fisher, Charles R.

2001-01-01

Vestimentiferan tubeworms, symbiotic with sulfur-oxidizing chemoautotrophic bacteria, dominate many cold-seep sites in the Gulf of Mexico. The most abundant vestimentiferan species at these sites, Lamellibrachia cf. luymesi, grows quite slowly to lengths exceeding 2 meters and lives in excess of 170–250 years. L. cf. luymesi can grow a posterior extension of its tube and tissue, termed a “root,” down into sulfidic sediments below its point of original attachment. This extension can be longer than the anterior portion of the animal. Here we show, using methods optimized for detection of hydrogen sulfide down to 0.1 μM in seawater, that hydrogen sulfide was never detected around the plumes of large cold-seep vestimentiferans and rarely detectable only around the bases of mature aggregations. Respiration experiments, which exposed the root portions of L. cf. luymesi to sulfide concentrations between 51–561 μM, demonstrate that L. cf. luymesi use their roots as a respiratory surface to acquire sulfide at an average rate of 4.1 μmol⋅g−1⋅h−1. Net dissolved inorganic carbon uptake across the plume of the tubeworms was shown to occur in response to exposure of the posterior (root) portion of the worms to sulfide, demonstrating that sulfide acquisition by roots of the seep vestimentiferan L. cf. luymesi can be sufficient to fuel net autotrophic total dissolved inorganic carbon uptake. PMID:11687647

Anatomy and origin of carbonate structures in a Miocene cold-seep field

Science.gov (United States)

Aiello, Ivano W.; Garrison, Robert E.; Moore, J. Casey; Kastner, Miriam; Stakes, Debra S.

2001-12-01

Miocene calcite concretions resembling modern carbonate structures that form at cold seeps are present in fractured opal- CT porcelanites that are interbedded with mudstones in coastal cliffs at Santa Cruz, California. The morphologies of the carbonate structures differ markedly from conventional concretions and are spatially aligned with orthogonal joints in the porcelanites. The structures contain tubular holes that are identical to fluid and gas conduits in modern carbonate seep structures; the orientations of these tubes suggest that fluid and gas flow was both vertical and horizontal, the latter along extensional joints that formed preferentially in the brittle, silica-rich layers that had enhanced bedding- parallel permeability. Petrographic and isotopic characteristics of the carbonate structures indicate that calcite precipitation occurred in a shallow, subseafloor environment in either the zone of microbial sulfate reduction or of methanogenesis, prior to or possibly simultaneously with the silica phase transformation of opal- A in diatom shells to opal-CT.

An Evaluation of Subsurface Plumbing of a Hydrothermal Seep Field and Possible Influence from Local Seismicity from New Time-Series Data Collected at the Davis-Schrimpf Seep Field, Salton Trough, California

Science.gov (United States)

Rao, A.; Onderdonk, N.

2016-12-01

The Davis­-Schrimpf Seep Field (DSSF) is a group of approximately 50 geothermal mud seeps (gryphons) in the Salton Trough of southeastern California. Its location puts it in line with the mapped San Andreas Fault, if extended further south, as well as within the poorly-understood Brawley Seismic Zone. Much of the geomorphology, geochemistry, and other characteristics of the DSSF have been analyzed, but its subsurface structure remains unknown. Here we present data and interpretations from five new temperature time­series from four separate gryphons at the DSSF, and compare them both amongst themselves, and within the context of all previously collected data to identify possible patterns constraining the subsurface dynamics. Simultaneously collected time-series from different seeps were cross-correlated to quantify similarity. All years' time-series were checked against the record of local seismicity to identify any seismic influence on temperature excursions. Time-series captured from the same feature in different years were statistically summarized and the results plotted to examine their evolution over time. We found that adjacent vents often alternate in temperature, suggesting a switching of flow path of the erupted mud at the scale of a few meters or less. Noticeable warming over time was observed in most of the features with time-series covering multiple years. No synchronicity was observed between DSSF features' temperature excursions, and seismic events within a 24 kilometer radius covering most of the width of the surrounding Salton Trough.

Stable isotopes provide new insights into vestimentiferan physiological ecology at Gulf of Mexico cold seeps

Science.gov (United States)

Becker, Erin Leigh; Macko, Stephen A.; Lee, Raymond W.; Fisher, Charles R.

2011-02-01

On the otherwise low-biomass seafloor of the Gulf of Mexico (GoM) continental slope, natural oil and gas seeps are oases of local primary production that support lush animal communities. Hundreds of seep communities have been documented on the continental slope, and nutrition derived from seeps could be an important link in the overall GoM food web. Here, we present a uniquely large and cohesive data set of δ13C, δ15N, and δ34S compositions of the vestimentiferan tubeworms Escarpia laminata and Lamellibrachia sp. 1, which dominate biomass at GoM seeps and provide habitat for hundreds of other species. Our sampling design encompassed an entire region of the GoM lower slope, allowing us for the first time to assess spatial variability in isotope compositions and to robustly address long-standing hypotheses about how vestimentiferans acquire and cycle nutrients over their long lifespan (200+ years). Tissue δ13C values provided strong evidence that larger adult vestimentiferans use their buried roots to take up dissolved inorganic carbon from sediment pore water, while very small individuals use their plume to take up carbon dioxide from the seawater. δ34S values were extremely variable among individuals of the same species within one location (<1 m2 area), indicating high variability in the inorganic sulfur pools on a very small spatial scale. This finding supports the hypothesis that vestimentiferans use their roots to cycle sulfate and sulfide between their symbionts and free-living consortia of sulfate-reducing archaea in the sediment. Finally, consistent differences in δ15N between two cooccurring vestimentiferan species provided the first strong evidence for partitioning of inorganic resources, which has significant implications for the ecology and evolution of this taxonomic group.

Fatty Acid and Carbon Isotopic Evidence for type I Methanotrophs in Microbial Mats from a Shallow Marine Gas Seep, Coal Oil Point, CA.

Science.gov (United States)

Ding, H.; Valentine, D.

2005-12-01

To study the microbial community in a Southern California seep field, sediment and bacterial mat samples were collected from natural gas-bearing and gas-free surfaces at two distinct seeps in the Coal Oil Point seep field, offshore Santa Barbara. Fatty acids in these samples were extracted, analyzed and identified. Using gas chromatography (GC), more than 30 different fatty acids were separated. Generally, fatty acid concentrations in natural gas-bearing samples were about 5-fold higher compared to gas-free samples. Using gas chromatography mass sepctrometry (GC-MS), all separated fatty acids were identified in each sample. The major constituents included saturated 14:0, 16:0, 18:0, branched i-15, a-15 and unsaturated 16:1 and 18:1 series fatty acids. GC-IRMS (isotope ratio mass spectrometry) analysis provided the 13C of all major fatty acids and some 16:1 series fatty acids were found to be more depleted than -40% in samples associated with gas seepage. After treatment with dimethyl disufide (DMDS), the 16:1 series fatty acids were resolved into five distinct components, including common composition 16:1(7), bacterial specific i-16:1(7) and typical biomarkers of type I methnotrophs 16:1(8), 16(6) and 16:1(5), suggesting an important role for methnotrophs in seep sediments and microbial mats. These results provide evidence for the activity of type I methanotrophic bacteria in microbial mats and surficial sediments at the Coal Oil Point seep field, and have implications for methane cycling in this and other seep

In situ environment rather than substrate type dictates microbial community structure of biofilms in a cold seep system

KAUST Repository

Lee, O.O.; Wang, Y.; Tian, R.; Zhang, W.; Shek, C.S.; Bougouffa, Salim; Al-Suwailem, A.; Batang, Z.B.; Xu, W.; Wang, G.C.; Zhang, Xixiang; Lafi, F.F.; Bajic, Vladimir B.; Qian, P.-Y.

2014-01-01

Using microscopic and molecular techniques combined with computational analysis, this study examined the structure and composition of microbial communities in biofilms that formed on different artificial substrates in a brine pool and on a seep vent of a cold seep in the Red Sea to test our hypothesis that initiation of the biofilm formation and spreading mode of microbial structures differs between the cold seep and the other aquatic environments. Biofilms on different substrates at two deployment sites differed morphologically, with the vent biofilms having higher microbial abundance and better structural features than the pool biofilms. Microbes in the pool biofilms were more taxonomically diverse and mainly composed of various sulfate-reducing bacteria whereas the vent biofilms were exclusively dominated by sulfur-oxidizing Thiomicrospira. These results suggest that the redox environments at the deployment sites might have exerted a strong selection on microbes in the biofilms at two sites whereas the types of substrates had limited effects on the biofilm development.

In situ environment rather than substrate type dictates microbial community structure of biofilms in a cold seep system

KAUST Repository

Lee, O.O.

2014-01-08

Using microscopic and molecular techniques combined with computational analysis, this study examined the structure and composition of microbial communities in biofilms that formed on different artificial substrates in a brine pool and on a seep vent of a cold seep in the Red Sea to test our hypothesis that initiation of the biofilm formation and spreading mode of microbial structures differs between the cold seep and the other aquatic environments. Biofilms on different substrates at two deployment sites differed morphologically, with the vent biofilms having higher microbial abundance and better structural features than the pool biofilms. Microbes in the pool biofilms were more taxonomically diverse and mainly composed of various sulfate-reducing bacteria whereas the vent biofilms were exclusively dominated by sulfur-oxidizing Thiomicrospira. These results suggest that the redox environments at the deployment sites might have exerted a strong selection on microbes in the biofilms at two sites whereas the types of substrates had limited effects on the biofilm development.

Toxicity of fuel-contaminated soil to Antarctic moss and terrestrial algae.

Science.gov (United States)

Nydahl, Anna C; King, Catherine K; Wasley, Jane; Jolley, Dianne F; Robinson, Sharon A

2015-09-01

Fuel pollution is a significant problem in Antarctica, especially in areas where human activities occur, such as at scientific research stations. Despite this, there is little information on the effects of petroleum hydrocarbons on Antarctic terrestrial biota. The authors demonstrate that the Antarctic mosses Bryum pseudotriquetrum, Schistidium antarctici, and Ceratodon purpureus, and the Antarctic terrestrial alga Prasiola crispa are relatively tolerant to Special Antarctic Blend (SAB) fuel-contaminated soil (measured as total petroleum hydrocarbons). Freshly spiked soils were more toxic to all species than were aged soils containing degraded fuel, as measured by photosynthetic efficiency (variable fluorescence/maximum fluorescence [Fv/Fm]), pigment content, and visual observations. Concentrations that caused 20% inhibition ranged from 16,600 mg/kg to 53,200 mg/kg for freshly spiked soils and from 30,100 mg/kg to 56,200 mg/kg for aged soils. The photosynthetic efficiency of C. purpureus and S. antarctici was significantly inhibited by exposure to freshly spiked soils with lowest-observed-effect concentrations of 27,900 mg/kg and 40,400 mg/kg, respectively. Prasiola crispa was the most sensitive species to freshly spiked soils (Fv/Fm lowest-observed-effect concentration 6700 mg/kg), whereas the Fv/Fm of B. pseudotriquetrum was unaffected by exposure to SAB fuel even at the highest concentration tested (62,900 mg/kg). Standard toxicity test methods developed for nonvascular plants can be used in future risk assessments, and sensitivity data will contribute to the development of remediation targets for petroleum hydrocarbons to guide remediation activities in Antarctica. © 2015 SETAC.

In situ Raman-based detections of the hydrothermal vent and cold seep fluids

Science.gov (United States)

Zhang, Xin; Du, Zengfeng; Zheng, Ronger; Luan, Zhendong; Qi, Fujun; Cheng, Kai; Wang, Bing; Ye, Wangquan; Liu, Xiaorui; Chen, Changan; Guo, Jinjia; Li, Ying; Yan, Jun

2016-04-01

Hydrothermal vents and cold seeps, and their associated biological communities play an important role in global carbon and sulphur biogeochemical cycles. Most of the studies of fluid composition geochemistry are based on recovered samples, both with gas-tight samplers and as open specimens, but the in situ conditions are difficult to maintain in recovered samples. Determination in situ of the chemical signals of the emerging fluids are challenging due to the high pressure, often strongly acidic and temperature in which few sensors can survive. Most of those sensors used so far are based on electrochemistry, and can typically detect only a few chemical species. Here we show that direct measurement of critical chemical species of hydrothermal vents and cold seeps can be made rapidly and in situ by means of a new hybrid version of earlier deep-sea pore water Raman probe carried on the ROV (Remote Operated Vehicle) Faxian. The fluid was drawn through the probe by actuating a hydraulic pump on the ROV, and measured at the probe optical cell through a sapphire window. We have observed the concentrations of H2S, HS-, SO42-, HSO4-, CO2, and H2 in hydrothermal vent fluids from the Pacmanus and Desmos vent systems in the Manus back-arc basin, Papua New Guinea. Two black smokers (279° C and 186° C) at the Pacmanus site showed the characteristic loss of SO42-, and the increase of CO2 and well resolved H2S and HS- peaks. At the white smoker of Onsen site the strong HSO4-peak observed at high temperature quickly dropped with strong accompanying increase of SO42-and H2 peaks when the sample contained in the Raman sensing cell was removed from the hot fluid due to rapid thermal deprotonation. We report here also the finding of a new lower temperature (88° C) white smoker "Kexue" field at the Desmos site with strong H2S, HS- and CO2 signals. We also have detected the concentrations of CH4,H2S, HS-, SO42-, and S8 in cold seep fluids and the surrounding sediment pore water from

Contrasting the Community Structure of Arbuscular Mycorrhizal Fungi from Hydrocarbon-Contaminated and Uncontaminated Soils following Willow (Salix spp. L.) Planting

OpenAIRE

Hassan, Saad El-Din; Bell, Terrence H.; Stefani, Franck O. P.; Denis, David; Hijri, Mohamed; St-Arnaud, Marc

2014-01-01

Phytoremediation is a potentially inexpensive alternative to chemical treatment of hydrocarbon-contaminated soils, but its success depends heavily on identifying factors that govern the success of root-associated microorganisms involved in hydrocarbon degradation and plant growth stimulation. Arbuscular mycorrhizal fungi (AMF) form symbioses with many terrestrial plants, and are known to stimulate plant growth, although both species identity and the environment influence this relationship. Al...

Characterisation of the nematode community of a low-activity cold seep in the recently ice-shelf free Larsen B area, Eastern Antarctic Peninsula.

Directory of Open Access Journals (Sweden)

Freija Hauquier

Full Text Available BACKGROUND: Recent climate-induced ice-shelf disintegration in the Larsen A (1995 and B (2002 areas along the Eastern Antarctic Peninsula formed a unique opportunity to assess sub-ice-shelf benthic community structure and led to the discovery of unexplored habitats, including a low-activity methane seep beneath the former Larsen B ice shelf. Since both limited particle sedimentation under previously permanent ice coverage and reduced cold-seep activity are likely to influence benthic meiofauna communities, we characterised the nematode assemblage of this low-activity cold seep and compared it with other, now seasonally ice-free, Larsen A and B stations and other Antarctic shelf areas (Weddell Sea and Drake Passage, as well as cold-seep ecosystems world-wide. PRINCIPAL FINDINGS: The nematode community at the Larsen B seep site differed significantly from other Antarctic sites in terms of dominant genera, diversity and abundance. Densities in the seep samples were high (>2000 individuals per 10 cm(2 and showed below-surface maxima at a sediment depth of 2-3 cm in three out of four replicates. All samples were dominated by one species of the family Monhysteridae, which was identified as a Halomonhystera species that comprised between 80 and 86% of the total community. The combination of high densities, deeper density maxima and dominance of one species is shared by many cold-seep ecosystems world-wide and suggested a possible dependence upon a chemosynthetic food source. Yet stable (13C isotopic signals (ranging between -21.97±0.86‰ and -24.85±1.89‰ were indicative of a phytoplankton-derived food source. CONCLUSION: The recent ice-shelf collapse and enhanced food input from surface phytoplankton blooms were responsible for the shift from oligotrophic pre-collapse conditions to a phytodetritus-based community with high densities and low diversity. The parthenogenetic reproduction of the highly dominant Halomonhystera species is rather unusual

Methane-metabolizing microbial communities in sediments of the Haima cold seep area, northwest slope of the South China Sea.

Science.gov (United States)

Niu, Mingyang; Fan, Xibei; Zhuang, Guangchao; Liang, Qianyong; Wang, Fengping

2017-09-01

Cold seeps are widespread chemosynthetic ecosystems in the deep-sea environment, and cold seep microbial communities of the South China Sea are poorly constrained. Here we report on the archaeal communities, particularly those involved in methane metabolization, in sediments of a newly discovered cold seep (named 'Haima') on the northwest slope of the South China Sea. Archaeal diversity, abundance and distribution were investigated in two piston cores collected from a seep area (QDN-14B) and a non-seep control site (QDN-31B). Geochemical investigation of the QDN-14B core identified an estimated sulfate-methane transition zone (Estimated SMTZ) at 300-400 cm below sea floor (cmbsf), where a high abundance of anaerobic methane-oxidizing archaea (ANME) occurred, as revealed by analysis of the 16S rRNA gene and the gene (mcrA) encoding the α-subunit of the key enzyme methyl-coenzyme M reductase. ANME-2a/b was predominant in the upper and middle layers of the estimated SMTZ, whereas ANME-1b outcompeted ANME-2 in the sulfate-depleted bottom layers of the estimated SMTZ and the methanogenic zone. Fine-scale phylogenetic analysis further divided the ANME-1b group into three subgroups with different distribution patterns: ANME-1bI, ANME-1bII and ANME-1bIII. Multivariate analyses indicated that dissolved inorganic carbon and sulfate may be important factors controlling the composition of the methane-metabolizing community. Our study on ANME niche separation and interactions with other archaeal groups improves our understanding of the metabolic diversity and flexibility of ANME, and the findings further suggest that ANME subgroups may have evolved diversified/specified metabolic capabilities other than syntrophic anaerobic oxidation of methane coupled with sulfate reduction in marine sediments. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Natural and anthropogenic hydrocarbon inputs to sediments of Patos Lagoon Estuary, Brazil.

Science.gov (United States)

Medeiros, Patricia Matheus; Bícego, Márcia Caruso; Castelao, Renato Menezes; Del Rosso, Clarissa; Fillmann, Gilberto; Zamboni, Ademilson Josemar

2005-01-01

The Patos Lagoon Estuary, southern Brazil, is an area of environmental interest not only because of tourism, but also because of the presence of the second major port of Brazil, with the related industrial and shipping activities. Thus, potential hydrocarbon pollution was examined in this study. Sediment samples were collected at 10 sites in the estuary, extracted, and analyzed by GC-FID and GC-MS for composition and concentration of the following organic geochemical markers: normal and isoprenoid alkanes, petroleum biomarkers, linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs). The total concentrations varied from 1.1 to 129.6 microg g(-1) for aliphatic hydrocarbons, from 17.8 to 4510.6 ng g(-1) for petroleum biomarkers, from 3.2 to 1601.9 ng g(-1) for LABs, and from 37.7 to 11,779.9 ng g(-1) for PAHs. Natural hydrocarbons were mainly derived from planktonic inputs due to a usual development of blooms in the estuary. Terrestrial plant wax compounds prevailed at sites located far from Rio Grande City and subject to stronger currents. Anthropogenic hydrocarbons are related to combustion/pyrolysis processes of fossil fuel, release of unburned oil products and domestic/industrial waste outfalls. Anthropogenic hydrocarbon inputs were more apparent at sites associated with industrial discharges (petroleum distributor and refinery), shipping activities (dry docking), and sewage outfalls (sewage). The overall concentrations of anthropogenic hydrocarbons revealed moderate to high hydrocarbon pollution in the study area.

Genomic and Transcriptomic Evidence for Carbohydrate Consumption among Microorganisms in a Cold Seep Brine Pool

KAUST Repository

Zhang, Weipeng; Ding, Wei; Yang, Bo; Tian, Renmao; Gu, Shuo; Luo, Haiwei; Qian, Pei-Yuan

2016-01-01

the Thuwal cold seep brine pool of the Red Sea. The recovered metagenome-assembled genomes (MAGs) belong to six different phyla: Actinobacteria, Proteobacteria, Candidatus Cloacimonetes, Candidatus Marinimicrobia, Bathyarchaeota, and Thaumarchaeota

Distribution and geochemical application of aromatic hydrocarbons in crude oils

International Nuclear Information System (INIS)

Asif, M.; Tahira, F.

2007-01-01

Distribution of aromatic hydrocarbons was studied in a set of crude oils, five from northern Indus basin of potwar area and two from southern Indus basin. Diaromatic and triaromatic hydrocarbons were separated from highly complex mixture of sedimentary organic matter by using liquid chromatography techniques such as column chromatography, TLC and GC-FID. These classes of compounds were identified to alkylated isomers of naphthalenes and phenanthrenes by using reference chromatograms and literature data. High concentration of di-,tri- and tetra-methyl naphthalenes was observed in all crude oils except Kal. The relative increase in concentration of alkyl naphthalenes was found as moved to higher methyl substituted isomers. This suggests that they are the product of sedimentary alkylation reactions during catagensis and metagensis. The significant concentration of methyl phenanthrenes indicated source of organic matter. High levels of both 1-MP and 9-MP showed marine and terrestrial source of organic matter except Umer crude oil which is most likely to have terrestrial origin. The ratios of beta-substituted to the alpha-substituted isomers of both alkyl naphthalenes and alkyl phenanthrene were used to assess the thermal maturity of sedimentary organic matter, which revealed high maturity level of Dhurnal, Pindori, Badin and Toot crude oils. (author)

Long-term Measurement of Sediment Resuspension and Gas Hydrate Stability at a Gulf of Mexico Seep Site

Science.gov (United States)

Vardaro, M. F.; Bender, L. C.; MacDonald, I. R.

2003-12-01

To study the temporal topographic and hydrologic changes in Gulf of Mexico cold seeps, we deployed a deep-sea time-lapse camera, several temperature probes and an ADCP mooring at the continental shelf seep community surrounding a gas hydrate outcropping. The digital camera recorded one still image every six hours for three months in 2001, every two hours for the month of June 2002 and every six hours for the month of July 2002. A pair of 300 kHz Workhorse acoustic Doppler current profilers (ADCPs) attached to a 540 meter-long mooring were anchored approximately 2 km from the site in 2002. Temperature probes were deployed at the site over the entire experimental period. The data recovered provide a comprehensive record of gas hydrate mound processes. We calculated biological activity by identifying fauna observed in the time-lapse record and recording the number of individuals and species seen in each image. 1,381 individual organisms representing over 20 species were observed. An average of 4.6 (+/-3.0) organisms were seen in each frame during the three-month deployment, while 3.6 (+/-4.2) were seen per frame in the one-month deployment. An extensive amount of sediment suspension and redistribution occurred during the deployment period. By digitally analyzing the luminosity of the water column above the mound and plotting the results over time the turbidity at the site could be quantified. A 24.1-hour diurnal pattern can be seen in the record, indicating a possible tidal or inertial component to deep-sea currents in this area. Contrary to expectations, there was no major change in shape or size of the gas hydrate outcrop being studied. This indicates a higher degree of stability than laboratory studies or prior in situ observations have shown. The stable topography of the gas hydrate mound combines with high organic output and sediment turnover to serve as a focus of benthic predatory activity. The frequency and recurrence of sediment resuspension indicate that

Submarine Exploration and Evaluation of Petroleum Seeps (SEEPS) (AT26-06, EM122)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Conduct in-situ incubations with devices for microbial growth, deployed in 2011. 2. Investigate the fate of dissolved hydrocarbons in the waters along the CA...

Carbon and hydrogen isotopic composition of methane and C2+ alkanes in electrical spark discharge: implications for identifying sources of hydrocarbons in terrestrial and extraterrestrial settings.

Science.gov (United States)

Telling, Jon; Lacrampe-Couloume, Georges; Sherwood Lollar, Barbara

2013-05-01

The low-molecular-weight alkanes--methane, ethane, propane, and butane--are found in a wide range of terrestrial and extraterrestrial settings. The development of robust criteria for distinguishing abiogenic from biogenic alkanes is essential for current investigations of Mars' atmosphere and for future exobiology missions to other planets and moons. Here, we show that alkanes synthesized during gas-phase radical recombination reactions in electrical discharge experiments have values of δ(2)H(methane)>δ(2)H(ethane)>δ(2)H(propane), similar to those of the carbon isotopes. The distribution of hydrogen isotopes in gas-phase radical reactions is likely due to kinetic fractionations either (i) from the preferential incorporation of (1)H into longer-chain alkanes due to the more rapid rate of collisions of the smaller (1)H-containing molecules or (ii) by secondary ion effects. Similar δ(13)C(C1-C2+) and δ(2)H(C1-C2+) patterns may be expected in a range of extraterrestrial environments where gas-phase radical reactions dominate, including interstellar space, the atmosphere and liquid hydrocarbon lakes of Saturn's moon Titan, and the outer atmospheres of Jupiter, Saturn, Neptune, and Uranus. Radical recombination reactions at high temperatures and pressures may provide an explanation for the combined reversed δ(13)C(C1-C2+) and δ(2)H(C1-C2+) patterns of terrestrial alkanes documented at a number of high-temperature/pressure crustal sites.

Biogeochemistry of Halogenated Hydrocarbons

Science.gov (United States)

Adriaens, P.; Gruden, C.; McCormick, M. L.

2003-12-01

Halogenated hydrocarbons originate from both natural and industrial sources. Whereas direct anthropogenic emissions to the atmosphere and biosphere are often easy to assess, particularly when they are tied to major industrial activities, the attribution of emissions to other human activities (e.g., biomass burning), diffuse sources (e.g., atmospheric discharge, run off), and natural production (e.g., soils, fungi, algae, microorganisms) are difficult to quantify. The widespread occurrence of both alkyl and aryl halides in groundwater, surface water, soils, and various trophic food chains, even those not affected by known point sources, suggests a substantial biogeochemical cycling of these compounds (Wania and Mackay, 1996; Adriaens et al., 1999; Gruden et al., 2003). The transport and reactive fate mechanisms controlling their reactivity are compounded by the differences in sources of alkyl-, aryl-, and complex organic halides, and the largely unknown impact of biogenic processes, such as enzymatically mediated halogenation of organic matter, fungal production of halogenated hydrocarbons, and microbial or abiotic transformation reactions (e.g., Asplund and Grimvall, 1991; Gribble, 1996; Watling and Harper, 1998; Oberg, 2002). The largest source may be the natural halogenation processes in the terrestrial environment, as the quantities detected often exceed the amount that can be explained by human activities in the surrounding areas ( Oberg, 1998). Since biogeochemical processes result in the distribution of a wide range of halogenated hydrocarbon profiles, altered chemical structures, and isomer distributions in natural systems, source apportionment (or environmental forensics) can often only be resolved using multivariate statistical methods (e.g., Goovaerts, 1998; Barabas et al., 2003; Murphy and Morrison, 2002).This chapter will describe the widespread occurrence of halogenated hydrocarbons, interpret their distribution and biogeochemical cycling in light of

Chasing Sources and Transports of Methane Plumes in the Northern Gulf of Mexico Using In Situ Sensors on Untethered Landers

Science.gov (United States)

Martens, C. S.; Mendlovitz, H.; Seim, H.; Lapham, L.; Magen, C.; Joye, S. B.; MacDonald, I. R.; Asper, V. L.; Diercks, A. R.

2016-02-01

In situ time-series measurements of light hydrocarbons, oxygen, temperature and bottom currents from landers and elevators in the benthic boundary layer (BBL) at multiple sites in the northern Gulf of Mexico reveal spatial and temporal variability in methane concentrations controlled by horizontal advection of methane-rich plumes originating from nearby natural oil and gas seeps. Multi-sensor systems deployed for several weeks within 1m of the seafloor at depths from 882 to 1622m revealed methane concentrations ranging from near atmospheric saturation (gas chromatography. Continuous laser sensor methane measurements from mini-landers deployed in September 2015 at our Horn Dome and Bush Hill sites featuring numerous gas seeps revealed methane concentrations ranging from data within the BBL and friction layer from untethered platforms provides important new opportunities for monitoring the impacts of natural seeps and accidental hydrocarbon releases. The instrumented approaches we have developed to simultaneously monitor methane sources and physical processes controlling plume development and transport will enable more effective responses to further accidental hydrocarbon releases.

Long-term toxicity of five polycyclic aromatic hydrocarbons for the terrestrial isopods Oniscus asellus and Porcellio scaber

Energy Technology Data Exchange (ETDEWEB)

Brummelen, T.C. van; Gestel, C.A.M. van; Verweij, R.A. [Vrije Univ., Amsterdam (Netherlands). Dept. of Ecology and Ecotoxicology

1996-07-01

Polycyclic aromatic hydrocarbons (PAHs) are a common component of soil pollution, yet little is known of the ecotoxicological risks these compounds may pose to life in soil. This article reports the ecotoxicity of five PAHs for two terrestrial isopod species. Isopods were exposed to food contaminated with four different concentrations of either fluorene, phenanthrene, fluoranthene (up to 4 {micro}mol/g), benz[a]anthracene, or benzo[a]pyrene (up to 1.25 {micro}mol/.g). Exposure of Porcellio scaber lasted 16 weeks, and no adverse effects on survival, growth, or total protein (only females tested) were observed in any of the treatments. A small but significant reduction in growth of Oniscus asellus was observed at 47 weeks of exposure to 0.125 {micro}mol benz[a]anthracene-g{sup {minus}1} dry weight and higher concentrations. A significant stimulation of the reproduction of O. asellus was observed in some of the phenanthrene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene treatments; a larger proportion of the females were gravid, which resulted in a higher number of juveniles per female. Exposure did not significantly affect brood size, weight of the mother after release of the juveniles, or the survival of the juveniles upon starvation. Total protein content of females was significantly reduced at 0.4 {micro}mol fluorene g{sup {minus}1} dry weight and higher concentrations. Growth and protein content of isopods is likely to be affected by PAH exposure only at highly contaminated sites. The ecological consequences of stimulated reproduction and possible DNA damage are poorly understood and require further attention because soil invertebrates may be exposed to PAHs over many generations.

Microbial utilization of naturally occurring hydrocarbons at the Guaymas Basin hydrothermal vent site

International Nuclear Information System (INIS)

Bazylinski, D.A.; Wirsen, C.O.; Jannasch, H.W.

1989-01-01

The Guaymas Basin (Gulf of California; depth, 2,000 m) is a site of hydrothermal activity in which petroliferous materials is formed by thermal alteration of deposited planktonic and terrestrial organic matter. We investigated certain components of these naturally occurring hydrocarbons as potential carbon sources for a specific microflora at these deep-sea vent sites. Respiratory conversion of [1- 14 C]hexadecane and [1(4,5,8)- 14 C]naphthalene to 14 CO 2 was observed at 4 degree C and 25 degree C, and some was observed at 55 degree C, but none was observed at 80 degree C. Bacterial isolates were capable of growing on both substrates as the sole carbon source. All isolates were aerobic and mesophilic with respect to growth on hydrocarbons but also grew at low temperatures (4 to 5 degree C). These results correlate well with previous geochemical analyses, indicating microbial hydrocarbon degradation, and show that at least some of the thermally produced hydrocarbons at Guaymas Basin are significant carbon sources to vent microbiota

Distribution of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and organochlorinated pollutants in deep-sea sediments of the Southern Cretan margin, Eastern Mediterranean Sea: a baseline assessment.

Science.gov (United States)

Mandalakis, Manolis; Polymenakou, Paraskevi N; Tselepides, Anastasios; Lampadariou, Nikolaos

2014-07-01

Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (ΣAH:326-3758ngg(-1), dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (ΣPAH:9-60ngg(-1)). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg(-1)), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg(-1)) and polychlorinated biphenyls (ΣPCB:38-1182pgg(-1)) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases. Copyright © 2014 Elsevier Ltd. All rights reserved.

A terrestrial Eocene stack: tying terrestrial lake ecology to marine carbon cycling through the Early Eocene Climatic Optimum

Science.gov (United States)

Grogan, D. S.; Whiteside, J. H.; Musher, D.; Rosengard, S. Z.; Vankeuren, M. A.; Pancost, R. D.

2010-12-01

The lacustrine Green River Formation is known to span ≥15 million years through the early-middle Eocene, and recent work on radioisotopic dating has provided a framework on which to build ties to the orbitally-tuned marine Eocene record. Here we present a spliced stack of Fischer assay data from drilled cores of the Green River Formation that span both an East-West and a North-South transect of the Uinta Basin of Utah. Detailed work on two cores demonstrate that Fischer assay measurements covary with total organic carbon and bulk carbon isotopes, allowing us to use Fisher assay results as a representative carbon cycling proxy throughout the stack. We provide an age model for this core record by combining radioisotopic dates of tuff layers with frequency analysis of Fischer assay measurements. Identification of orbital frequencies tied directly to magnetochrons through radioisotopic dates allows for a direct comparison of the terrestrial to the marine Eocene record. Our analysis indicates that the marker beds used to correlate the stack cores represent periods of enhanced lake productivity and extreme carbon burial; however, unlike the hyperthermal events that are clearly marked in the marine Eocene record, the hydrocarbon-rich "Mahogany Bed" period of burial does not correspond to a clear carbon isotope excursion. This suggests that the terrestrial realm may have experienced extreme ecological responses to relatively small perturbations in the carbon cycle during the Early Eocene Climatic Optimum. To investigate the ecological responses to carbon cycle perturbations through the hydrocarbon rich beds, we analyzed a suite of microbial biomarkers, finding evidence for cyanobacteria, dinoflagellates, and potentially green sulfur bacteria. These taxa indicate fluctuating oxic/anoxic conditions in the lake during abrupt intervals of carbon burial, suggesting a lake biogeochemical regime with no modern analogues.

Ecological risk assessment of a site contaminated with petroleum hydrocarbons

International Nuclear Information System (INIS)

Starodub, M.E.; Feniak, N.A.; Willes, R.F.; Moore, C.E.; Mucklow, L.

1995-01-01

The aquatic and terrestrial health risks associated with petroleum contamination on a decommissioned military base, contaminated with products ranging from Bunker C oil to aviation fuel, were assessed using a methodology whereby an analytical measurement of total petroleum hydrocarbons (TPH) could be correlated with compositional characterization and thus with toxicity. The constituents of petroleum hydrocarbon contamination represent wide ranges of physical-chemical properties, environmental fate, and toxicity. The composition of TPH can vary greatly, dependent on the sources or fuel types and the interaction of age as well as site- and chemical-specific characteristics in determining the impact of weathering processes. Therefore, a bulk sum analysis of TPH cannot be related to toxicity without characterization of its composition and association of the constituents, and therefore composition, with actual toxicity data. To address this need, the constituents of TPH were represented by surrogate chemicals, with selection based on structure-activity relationships and available toxicity data. Toxicological profiles were developed from governmental regulations and on the published literature for both the aquatic and terrestrial media. Risk characterization consisted of a comparison of water concentration limits and exposure limits, developed for each surrogate, to estimated surrogate concentrations throughout the site. The concentrations of surrogates were extrapolated from TPH composition characterization analyses, conducted at a select number of sampling locations, to bulk sum analyses of TPH at related sampling locations

Marine controlled source electromagnetics on the Hikurangi Margin, NZ : coincidence between cold seep sites and electrical resistivity anomalies indicating sub-seafloor gas hydrate deposits

Energy Technology Data Exchange (ETDEWEB)

Schwalenberg, K. [Federal Inst. for Geosciences and Natural Resources, Hannover (Germany); Pecher, I. [Heriot Watt Univ., Edinburgh (United Kingdom). Inst. of Petroleum Engineering; Netzeband, G.; Jegen, M. [IFM-GEOMAR, Kiel (Germany); Port, J. [Ghent Univ., Ghent (Belgium). Renard Centre of Marine Geology

2008-07-01

This study examined the use of marine-controlled source electromagnetic (CSEM) measurements for monitoring the control, release and transformation of methane from gas seep sites and deposits on the Hikurangi Margin near New Zealand. The CSEM experiments were conducted to determine the electrical signature of the gas seeps as a means of identifying the presence of gas hydrate deposits. Data for 4 profiles were obtained and inverted to sub-sea floor resistivities and 1-D layered earth models. An analysis of the data showed a relationship between anomalous resistivities and the location of gas seep sites. Results suggested that concentrated gas hydrates were the cause of the anomalous resistivities. Data obtained from the southeast corner of the North Islands suggested the presence of gas hydrates in the first 100 m of bottom simulating reflector (BSM) data. Seeps were also identified in seismic data that showed faults and high amplitude reflections. A seep site with no resistivity anomalies but with active venting, high heat flow, and seismic fault planes was also identified. The lack of resistive anomalies was attributed to lower concentrations of gas hydrates; strong temporal and spatial variations; and temperature-driven fluid expulsion that hampered gas hydrate formation beneath the vent. The final profile examined in the study demonstrated a single anomaly over a deep, uprising reflective zone cause by both free gas and gas hydrates. 25 refs., 1 tab., 11 figs.

Methane sources in gas hydrate-bearing cold seeps: Evidence from radiocarbon and stable isotopes

Science.gov (United States)

Pohlman, J.W.; Bauer, J.E.; Canuel, E.A.; Grabowski, K.S.; Knies, D.L.; Mitchell, C.S.; Whiticar, Michael J.; Coffin, R.B.

2009-01-01

Fossil methane from the large and dynamic marine gas hydrate reservoir has the potential to influence oceanic and atmospheric carbon pools. However, natural radiocarbon (14C) measurements of gas hydrate methane have been extremely limited, and their use as a source and process indicator has not yet been systematically established. In this study, gas hydrate-bound and dissolved methane recovered from six geologically and geographically distinct high-gas-flux cold seeps was found to be 98 to 100% fossil based on its 14C content. Given this prevalence of fossil methane and the small contribution of gas hydrate (??? 1%) to the present-day atmospheric methane flux, non-fossil contributions of gas hydrate methane to the atmosphere are not likely to be quantitatively significant. This conclusion is consistent with contemporary atmospheric methane budget calculations. In combination with ??13C- and ??D-methane measurements, we also determine the extent to which the low, but detectable, amounts of 14C (~ 1-2% modern carbon, pMC) in methane from two cold seeps might reflect in situ production from near-seafloor sediment organic carbon (SOC). A 14C mass balance approach using fossil methane and 14C-enriched SOC suggests that as much as 8 to 29% of hydrate-associated methane carbon may originate from SOC contained within the upper 6??m of sediment. These findings validate the assumption of a predominantly fossil carbon source for marine gas hydrate, but also indicate that structural gas hydrate from at least certain cold seeps contains a component of methane produced during decomposition of non-fossil organic matter in near-surface sediment.

Origins of hydrocarbon gas seeping out from offshore mud volcanoes in the Nile delta

Science.gov (United States)

Prinzhofer, Alain; Deville, Eric

2013-04-01

This paper discusses the origin of gas seepages (free gas or dissolved gas in ground water or brine) sampled with the Nautile submarine during the Nautinil cruise at the seafloor of the deep water area of the Nile turbiditic system on different mud volcanoes and brine pools. Generally, the gas is wet and includes C1, C2, C3, iC4, nC4, CO2. These gas samples show no evidence of biodegradation which is not the case of the gas present in the deep hydrocarbon accumulations at depth. It indicates that the gas expelled by the mud volcanoes is not issued from direct leakages from deep gas fields. The collected gas samples mainly have a thermogenic origin and show different maturities. Some samples show very high maturities indicating that these seepages are sourced from great depths, below the Messinian salt. Moreover, the different chemical compositions of the gas samples reflect not only differences in maturity but also the fact that the gas finds its origin in different deep source rocks. Carbon dioxide has an organic signature and cannot result from carbonate decomposition or mantle fluids. The crustal-derived radiogenic isotopes show that the analyzed gas samples have suffered a fractionation processes after the production of the radiogenic isotopes, due either to oil occurrence at depth interacting with the flux of gas, and/or fractionation during the fluid migration.

Microbial community changes along the active seepage site of one cold seep in the Red Sea.

KAUST Repository

Cao, Huiluo

2015-07-21

The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

Microbial community changes along the active seepage site of one cold seep in the Red Sea.

KAUST Repository

Cao, Huiluo; Zhang, Weipeng; Wang, Yong; Qian, Pei-Yuan

2015-01-01

The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal (AOA) communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of AOA in different habitats (water vs. sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep.

Characterization of Preferential Ground-Water Seepage From a Chlorinated Hydrocarbon-Contaminated Aquifer to West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 2002-04

Science.gov (United States)

Majcher, Emily H.; Phelan, Daniel J.; Lorah, Michelle M.; McGinty, Angela L.

2007-01-01

Wetlands act as natural transition zones between ground water and surface water, characterized by the complex interdependency of hydrology, chemical and physical properties, and biotic effects. Although field and laboratory demonstrations have shown efficient natural attenuation processes in the non-seep wetland areas and stream bottom sediments of West Branch Canal Creek, chlorinated volatile organic compounds are present in a freshwater tidal creek at Aberdeen Proving Ground, Maryland. Volatile organic compound concentrations in surface water indicate that in some areas of the wetland, preferential flow paths or seeps allow transport of organic compounds from the contaminated sand aquifer to the overlying surface water without undergoing natural attenuation. From 2002 through 2004, the U.S. Geological Survey, in cooperation with the Environmental Conservation and Restoration Division of the U.S. Army Garrison, Aberdeen Proving Ground, characterized preferential ground-water seepage as part of an ongoing investigation of contaminant distribution and natural attenuation processes in wetlands at this site. Seep areas were discrete and spatially consistent during thermal infrared surveys in 2002, 2003, and 2004 throughout West Branch Canal Creek wetlands. In these seep areas, temperature measurements in shallow pore water and sediment more closely resembled those in ground water than those in nearby surface water. Generally, pore water in seep areas contaminated with chlorinated volatile organic compounds had lower methane and greater volatile organic compound concentrations than pore water in non-seep wetland sediments. The volatile organic compounds detected in shallow pore water in seeps were spatially similar to the dominant volatile organic compounds in the underlying Canal Creek aquifer, with both parent and anaerobic daughter compounds detected. Seep locations characterized as focused seeps contained the highest concentrations of chlorinated parent compounds

Chronic oiling of marine birds in California by natural petroleum seeps, shipwrecks, and other sources.

Science.gov (United States)

Henkel, Laird A; Nevins, Hannahrose; Martin, Marida; Sugarman, Susan; Harvey, James T; Ziccardi, Michael H

2014-02-15

We assessed temporal and spatial patterns of chronic oiling of seabirds in California during 2005-2010, using data on: (1) live oiled birds reported to the Oiled Wildlife Care Network (OWCN) from throughout the state, and (2) dead oiled birds found during systematic monthly beached-bird surveys in central California. A mean of 245 (± 141 SD) live miscellaneous oiled birds (not associated with known oil spills) were reported to the OWCN per year, and 0.1 oiled dead birds km(-1) per month were found on beach surveys in central California. Chemical fingerprinting of oiled feathers from a subset of these birds (n=101) indicated that 89% of samples tested were likely from natural petroleum seeps off southern and central California. There was a pronounced peak during late winter in the number of oiled birds reported in southern California, which we theorize may be related to large storm waves disturbing underwater seeps. Copyright © 2014 Elsevier Ltd. All rights reserved.

Extreme Morphologic and Venting Changes in Methane Seeps at Southern Hydrate Ridge, Cascadia Margin

Science.gov (United States)

Bigham, K.; Kelley, D. S.; Solomon, E. A.; Delaney, J. R.

2017-12-01

Two highly active methane hydrate seeps have been visited over a 7-year period as part of the construction and operation of NSF's Ocean Observatory Initiative's Regional Cable Array at Southern Hydrate Ridge. The site is located 90 km west of Newport, Oregon, at a water depth of 800 m. The seeps, Einstein's Grotto (OOI instrument deployment site) and Smokey Tavern (alternate site to the north), have been visited yearly from 2010 to 2017 with ROVs. Additionally, a digital still camera deployed from 2014 to 2017 at Einstein's Grotto, has been documenting the profound morphologic and biological changes at this site. A cabled pressure sensor, Acoustic Doppler Current Profiler, hydrophone, seismometer array, and uncabled fluid samplers have also been operational at the site for the duration of the camera's deployment. During this time, Einstein's Grotto has evolved from a gentle mound with little venting, to a vigorously bubbling pit bounded by a near vertical wall. Early on bubble emissions blew significant amounts of sediment into the water column and thick Beggiatoa mats coverd the mound. Most recently the face of the pit has collapsed, although bubble plumes are still emitted from the site. The Smokey Tavern site has undergone more extreme changes. Similar to Einstein's Grotto it was first characterized by gentle hummocks with dispersed bacterial mats. In subsequent years, it developed an extremely rugged, elongated collapsed area with vertical walls and jets of methane bubbles rising from small pits near the base of the collapse zone. Meter-across nearly sediment-free blocks of methane hydrate were exposed on the surface and in the walls of the collapse zone. In 2016, this area was unrecognizable with a much more subdued topography, and weak venting of bubbles. Exposed methane hydrate was not visible. From these observations new evolutionary models for methane seeps are being developed for Southern Hydrate Ridge.

The Effect of Summer Environmental Education Program (SEEP) on Elementary School Students' Environmental Literacy

Science.gov (United States)

Erdogan, Mehmet

2015-01-01

The purpose of this study was to assess the effects of Summer Environmental Education Program (SEEP) on elementary school students' environmental knowledge, affect, skills and behavior which are the main components of environmental literacy. The sample consisted of 45 students (25 males, 20 females) studying in 4th through 8th grades and living in…

MOLECULAR DIAGNOSTIC RATIOS TO ASSESS THE APPORTIONMENT OF PETROLEUM HYDROCARBONS CONTAMINANTION IN MARINE SEDIMENT

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Agung Dhamar Syakti

2016-11-01

Full Text Available As maritime fulcrum nation, in Indonesia, marine environmental analytical chemistry field is still under developed. So that why, this review paper aims to provide basic understanding of the use some molecular diagnostic indices using n-alkanes indexes and polycyclic aromatic hydrocarbons (PAHs diagnostic ratios to estimate the source of apportionment of the hydrocarbons contamination and origin. The n-alkane chromatograms were then used to characterize the predominance of petrogenic or biogenic either terrestrial or aquatic. Furthermore, characterization allowed to discriminate riverine versus marine input. The occurrence of a broad unresolved complex mixture can be an evidence of biodegraded petroleum residues. For aromatic compounds, the prevalence of petrogenic, pyrolitic, and combustion-derived can be easily plotted by using isomers ratio calculation. This paper thus provides useful information on the hydrocarbon contamination origin, especially in marine sediments. Further researches should be undertaken in order to validate the use of molecular diagnostic ratio with isotopic approach.

Biomarker chemistry and flux quantification methods for natural petroleum seeps and produced oils, offshore southern California

Science.gov (United States)

Lorenson, T.D.; Leifer, Ira; Wong, Florence L.; Rosenbauer, Robert J.; Campbell, Pamela L.; Lam, Angela; Hostettler, Frances D.; Greinert, Jens; Finlayson, David P.; Bradley, Eliza S.; Luyendyk, Bruce P.

2011-01-01

Sustained, natural oil seepage from the seafloor is common off southern California, and is of great interest to resource managers, who are tasked with distinguishing natural from anthropogenic oil sources. The major purpose of this study was to build upon the work previously funded by the Bureau of Ocean Energy Management (BOEM) and the U.S. Geological Survey (USGS) that has refined the oil-fingerprinting process to enable differentiation of the highly similar Monterey Formation oils from Outer Continental Shelf (OCS) production and adjacent natural seeps. In these initial studies, biomarker and stable carbon isotope ratios were used to infer the age, lithology, organic-matter input, and depositional environment of the source rocks for 388 samples of produced crude oil, seep oil, and tarballs mainly from coastal California. The analysis resulted in a predictive model of oil source families that could be applied to samples of unknown origin.

Modeling the mutualistic interactions between tubeworms and microbial consortia.

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Erik E Cordes

2005-03-01

Full Text Available The deep-sea vestimentiferan tubeworm Lamellibrachia luymesi forms large aggregations at hydrocarbon seeps in the Gulf of Mexico that may persist for over 250 y. Here, we present the results of a diagenetic model in which tubeworm aggregation persistence is achieved through augmentation of the supply of sulfate to hydrocarbon seep sediments. In the model, L. luymesi releases the sulfate generated by its internal, chemoautotrophic, sulfide-oxidizing symbionts through posterior root-like extensions of its body. The sulfate fuels sulfate reduction, commonly coupled to anaerobic methane oxidation and hydrocarbon degradation by bacterial-archaeal consortia. If sulfate is released by the tubeworms, sulfide generation mainly by hydrocarbon degradation is sufficient to support moderate-sized aggregations of L. luymesi for hundreds of years. The results of this model expand our concept of the potential benefits derived from complex interspecific relationships, in this case involving members of all three domains of life.

Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

Science.gov (United States)

Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

2013-07-02

A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

Dynamics of hydrocarbon vents: Focus on primary porosity

Science.gov (United States)

Johansen, C.; Shedd, W.; Abichou, T.; Pineda-Garcia, O.; Silva, M.; MacDonald, I. R.

2012-12-01

This study investigated the dynamics of hydrocarbon release by monitoring activity of a single vent at a 1215m deep site in the Gulf of Mexico (GC600). An autonomous camera, deployed by the submersible ALVIN, was programmed to capture a close-up image every 4 seconds for approximately 3.5 hours. The images provided the ability to study the gas hydrate outcrop site (that measured 5.2x16.3cm3) in an undisturbed state. The outcrop included an array of 38 tube-like vents through which dark brown oil bubbles are released at a rate ranging from 8 bubbles per minute to 0 bubbles per minute. The average release of bubbles from all the separate vents was 59.5 bubbles per minute, equating the total volume released to 106.38cm per minute. The rate of bubble release decreased toward the end of the observation interval, which coincided approximately with the tidal minimum. Ice worms (Hesiocaeca methanicola, Desbruyères & Toulmond, 1998) were abundant at the vent site. The image sequence showed the ice-worms actively moving in and out of burrows in the mound. It has been speculated that Hesiocaeca methanicola contribute to gas hydrate decomposition by creating burrows and depressions in the gas hydrate matrix (Fisher et al, 2000). Ice worm burrows could generate pathways for the passage of oil and gas through the gas hydrate mound. Gas hydrates commonly occur along active and/or passive continental margins (Kennicutt et al, 1988a). The release of oil and gas at this particular hydrocarbon seep site is along a passive continental margin, and controlled primarily by active salt tectonics as opposed to the movement of continental tectonic plates (Salvador, 1987). We propose a descriptive model governing the release of gas and oil from deep sub-bottom reservoirs at depths of 3000-5000m (MacDonald, 1998), through consolidated and unconsolidated sediments, and finally through gas hydrate deposits at the sea floor. The oil and gas escape from the source rock and/or reservoir through

High pH microbial ecosystems in a newly discovered, ephemeral, serpentinizing fluid seep at Yanartaş (Chimera), Turkey.

Science.gov (United States)

Meyer-Dombard, D'Arcy R; Woycheese, Kristin M; Yargıçoğlu, Erin N; Cardace, Dawn; Shock, Everett L; Güleçal-Pektas, Yasemin; Temel, Mustafa

2014-01-01

Gas seeps emanating from Yanartaş (Chimera), Turkey, have been documented for thousands of years. Active serpentinization produces hydrogen and a range of carbon gases that may provide fuel for life. Here we report a newly discovered, ephemeral fluid seep emanating from a small gas vent at Yanartaş. Fluids and biofilms were sampled at the source and points downstream. We describe site conditions, and provide microbiological data in the form of enrichment cultures, Scanning electron microscopy (SEM), carbon and nitrogen isotopic composition of solids, and PCR screens of nitrogen cycle genes. Source fluids are pH 11.95, with a Ca:Mg of ~200, and sediments under the ignited gas seep measure 60°C. Collectively, these data suggest the fluid is the product of active serpentinization at depth. Source sediments are primarily calcite and alteration products (chlorite and montmorillonite). Downstream, biofilms are mixed with montmorillonite. SEM shows biofilms distributed homogeneously with carbonates. Organic carbon accounts for 60% of the total carbon at the source, decreasing downstream to <15% as inorganic carbon precipitates. δ(13)C ratios of the organic carbon fraction of solids are depleted (-25 to -28‰) relative to the carbonates (-11 to -20‰). We conclude that heterotrophic processes are dominant throughout the surface ecosystem, and carbon fixation may be key down channel. δ(15)N ratios ~3‰, and absence of nifH in extracted DNA suggest that nitrogen fixation is not occurring in sediments. However, the presence of narG and nirS at most locations and in enrichments indicates genomic potential for nitrate and nitrite reduction. This small seep with shallow run-off is likely ephemeral, but abundant preserved microterracettes in the outflow and the surrounding area suggest it has been present for some time. This site and others like it present an opportunity for investigations of preserved deep biosphere signatures, and subsurface-surface interactions.

High pH microbial ecosystems in a newly discovered, ephemeral, serpentinizing fluid seep at Yanartaş (Chimaera, Turkey

Directory of Open Access Journals (Sweden)

D'Arcy Renee Meyer-Dombard

2015-01-01

Full Text Available Gas seeps emanating from ophiolites at Yanartaş (Chimaera, Turkey, have been documented for thousands of years. Active serpentinization produces hydrogen and a range of carbon gases that may provide fuel for life. Here we report a newly discovered, ephemeral fluid seep emanating from a small gas vent at Yanartaş. Fluids and biofilms were sampled at the source and points downstream. We describe site conditions, and provide microbiological data in the form of enrichment cultures, scanning electron microscopy (SEM, carbon and nitrogen isotopic composition of solids, and PCR screens of nitrogen cycle genes. Source fluids are pH 11.95, with a Ca:Mg of ~200, and sediments under the ignited gas seep measure 60°C. Collectively, these data suggest the fluid is the product of active serpentinization at depth. Source sediments are primarily calcite and alteration products (chlorite and montmorillonite. Downstream, biofilms are mixed with montmorillonite. SEM shows biofilms distributed homogeneously with carbonates. Organic carbon accounts for 60% of the total carbon at the source, decreasing downstream to <15% as inorganic carbon precipitates. δ13C ratios of the organic carbon fraction of solids are depleted (−25 to −28 ‰ relative to the carbonates (−11 to −20‰. We conclude that heterotrophic processes are dominant throughout the surface ecosystem, and carbon fixation may be key down channel. δ15N ratios ~ 3‰, and absence of nifH in extracted DNA suggest that nitrogen fixation is not occurring in sediments. However, the presence of narG and nirS at most locations and in enrichments indicates genomic potential for nitrate and nitrite reduction. This small seep with shallow run-off is likely ephemeral, but abundant preserved microterracettes in the outflow and the surrounding area suggest it has been present for some time. This site and others like it present an opportunity for investigations of preserved deep biosphere signatures, and

Authigenic carbonates from newly discovered active cold seeps on the northwestern slope of the South China Sea: Constraints on fluid sources, formation environments, and seepage dynamics

Science.gov (United States)

Liang, Qianyong; Hu, Yu; Feng, Dong; Peckmann, Jörn; Chen, Linying; Yang, Shengxiong; Liang, Jinqiang; Tao, Jun; Chen, Duofu

2017-06-01

Authigenic carbonates recovered from two newly discovered active cold seeps on the northwestern slope of the South China Sea have been studied using petrography, mineralogy, stable carbon and oxygen isotopic, as well as trace element compositions, together with AMS 14C ages of shells of seep-dwelling bivalves to unravel fluid sources, formation conditions, and seepage dynamics. The two seeps (ROV1 and ROV2), referred to as 'Haima seeps' herein, are approximately 7 kilometers apart, and are typified by abundant carbonate rocks represented bycrusts and nodules. Aragonite and high-Mg calcite are the main carbonate minerals. Based on low δ13Ccarbonate values ranging from -43.0‰ to -27.5‰ (V-PDB) methane is apparently the predominant carbon source of seep carbonates. The corresponding δ18O values, varying from 2.5‰ to 5.8‰ (V-PDB), mostly are higher than calculated values representing precipitation in equilibrium with seawater (2.5‰ to 3.8‰), which probably reflects past destabilization of locally abundant gas hydrates. In addition, we found that carbonates with bivalve shells are generally aragonite-dominated, and bear no barium enrichment but uranium enrichments, reflecting shallow formation depths close to the seafloor. In contrast, carbonate crusts without bivalve shells and nodules contain more calcite, and are characterized by major molybdenum enrichment and different degrees of barium enrichment, agreeing with precipitation at greater depth under strictly anoxic conditions. AMS 14C ages suggest that a major episode of carbonate precipitation occurred between 6.1 ka and 5.1 ka BP at the Haima seeps, followed by a possibly subordinate episode from approximately 3.9 ka to 2.9 ka BP. The common occurrence of dead bivalves at both sites indicates that chemosynthesis-based communities flourished to a greater extent in the past, probably reflecting a decline of seepage activity in recent times. Overall, these results confirm that authigenic carbonates from

Relationship of oil seep in Kudat Peninsula with surrounding rocks based on geochemical analysis

Science.gov (United States)

Izzati Azman, Nurul; Nur Fathiyah Jamaludin, Siti

2017-10-01

This study aims to investigate the relation of oil seepage at Sikuati area with the structural and petroleum system of Kudat Peninsula. The abundance of highly carbonaceous rocks with presence of lamination in the Sikuati Member outcrop at Kudat Peninsula may give an idea on the presence of oil seepage in this area. A detailed geochemical analysis of source rock sample and oil seepage from Sikuati area was carried out for their characterization and correlation. Hydrocarbon propectivity of Sikuati Member source rock is poor to good with Total Organic Carbon (TOC) value of 0.11% to 1.48%. and also categorized as immature to early mature oil window with Vitrinite Reflectance (VRo) value of 0.43% to 0.50 %Ro. Based on biomarker distribution, from Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS) analysis, source rock sample shows Pr/Ph, CPI and WI of 2.22 to 2.68, 2.17 to 2.19 and 2.46 to 2.74 respectively indicates the source rock is immature and coming from terrestrial environment. The source rock might be rich in carbonaceous material organic matter resulting from planktonic/bacterial activity which occurs at fluvial to fluvio-deltaic environment. Overall, the source rock from outcrop level of Kudat Peninsula is moderately prolific in term of prospectivity and maturity. However, as go far deeper beneath the surface, we can expect more activity of mature source rock that generate and expulse hydrocarbon from the subsurface then migrating through deep-seated fault beneath the Sikuati area.

Applicability of the black slug Arion ater for monitoring exposure to polycyclic aromatic hydrocarbons and their subsequent bioactivation into DNA binding metabolites

NARCIS (Netherlands)

Hamers, T.; Kalis, E.J.J.; Berg, van den J.H.J.; Maas, L.M.; Schooten, van F.J.; Murk, A.J.

2004-01-01

The applicability of terrestrial black slugs Arion ater (Mollusca, Gastropoda) was studied for biomonitoring environmental exposure to polycyclic aromatic hydrocarbons (PAHs). In laboratory experiments, slugs were orally exposed to benzo[a]pyrene (BaP) for a short term (3 days) or a long term (119

Investigating the emission, dissolution, and oxidation of CH4 within and around a seep bubble plume in the Gulf of Mexico.

Science.gov (United States)

Leonte, M.; Kessler, J. D.; Socolofsky, S. A.

2016-02-01

One of the largest carbon reservoirs on the planet is stored as methane (CH4) in and below the seafloor. However, a large discrepancy exists between estimated fluxes of CH4 into the water column and CH4 fluxes from the sea surface to the atmosphere, suggesting that a significant fraction of CH4 released from seafloor seeps is dissolved and potentially removed through microbial oxidation. Here we present data investigating the fate of CH4 released from the Sleeping Dragon seep site in the Gulf of Mexico. The bubble plume was followed from the seafloor until it fully dissolved using a remotely operated vehicle (ROV). Water samples were collected by the ROV at different depths as well as lateral transects through the bubble plume. These samples were analyzed for dissolved concentrations of methane, ethane, propane, and butane as well as the 13C isotopic ratio of methane. Furthermore, seep bubbles from the seafloor were also collected and analyzed for the same properties. Based on these chemical data, the rate of CH4 emission from the seafloor, oxidation in the water column, and dissolution are investigated.

Geological Study of Active Cold Seeps in the Syn-collision Accretionary Prism Kaoping Slope off SW Taiwan

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Chi-Yue Huang

2006-01-01

Full Text Available Pogonophoran tube worms, elongated pyrite tubes and authigenic carbonate nodules are used to evaluate the occurrence of potential cold seeps in the syn-collision accretionary prism Kaoping Slope off SW Taiwan. At least two species of pogonophoran tubeworms were found in surface and core sediments. Pyrites occur in three different forms: fillings inside foraminiferal chambers, cements between calcareous microfossils, and elongated tubes. The bottom water off SW Taiwan is aerobic, but authigenic pyrites are found in the surface sediments at several sites, suggesting the existence of local reducing environments enabling the formation of pyrites. These environments are most likely caused by the occurrence of active cold seeps where methane expulses. Authigenic carbonates with highly depleted carbon isotope values (-54 to -43‰ were found at more than 5 locations, in agreement with a methane-derived source for the carbon.

Hydrocarbon Migration from the Micro to Macro Scale in the Gulf of Mexico

Science.gov (United States)

Johansen, C.; Marty, E.; Silva, M.; Natter, M.; Shedd, W. W.; Hill, J. C.; Viso, R. F.; Lobodin, V.; Krajewski, L.; Abrams, M.; MacDonald, I. R.

2016-02-01

as these features progress with persistent hydrocarbon influx. Bottom features along with seismic data, bubble release rates and bubble composition (oily vs gaseous), are implemented into our model to describe the relative vent age and dynamic mechanisms of hydrocarbon migration at three vertical spatial scales of oily and gaseous natural seeps in the GoM.

Hydrocarbon footprints as a record of bumblebee flower visitation.

Science.gov (United States)

Witjes, Sebastian; Eltz, Thomas

2009-11-01

Bumblebees leave traces of cuticular hydrocarbons on flowers they visit, with the amount deposited being positively related to the number of visits. We asked whether such footprint hydrocarbons are retained on flowers for sufficiently long periods of time so as to reflect bee visitation in pollination studies. In laboratory experiments, flower corollae (Primula veris, Digitalis grandiflora) visited by Bombus terrestris workers retained bee-derived nonacosenes (C(29)H(58)) in near-unchanged quantities for 24 hours, both at 15 and 25 degrees C. Additionally, synthetic (Z)-9-tricosene applied to flower corollae of the deadnettle Lamium maculatum was retained for 48 hours in an unchanged quantity. In a field survey, the amount of footprint alkenes on flowers of comfrey (Symphytum officinale) plants was positively correlated with the number of bumblebee visits that those plants had received during the day. Together, these data suggest that flowers retain a long-term quantitative record of bumblebee visitation. The analysis of petal extracts by gas chromatography could provide a cheap and reliable way of quantifying bumblebee visits in landscape scale studies of pollination.

Diversity, abundance and distribution of amoA-encoding archaea in deep-sea methane seep sediments of the Okhotsk Sea.

Science.gov (United States)

Dang, Hongyue; Luan, Xi-Wu; Chen, Ruipeng; Zhang, Xiaoxia; Guo, Lizhong; Klotz, Martin G

2010-06-01

The ecological characteristics of amoA-encoding archaea (AEA) in deep-sea sediments are largely unsolved. This paper aimed to study the diversity, structure, distribution and abundance of the archaeal community and especially its AEA components in the cold seep surface sediments of the Okhotsk Sea, a marginal sea harboring one of the largest methane hydrate reservoirs in the world. Diverse archaeal 16S rRNA gene sequences were identified, with the majority being related to sequences from other cold seep and methane-rich sediment environments. However, the AEA diversity and abundance were quite low as revealed by amoA gene analyses. Correlation analysis indicates that the abundance of the archaeal amoA genes was correlated with the sediment organic matter content. Thus, it is possible that the amoA-carrying archaea here might utilize organic matter for a living. The affiliation of certain archaeal amoA sequences to the GenBank sequences originally obtained from deep-sea hydrothermal vent environments indicated that the related AEA either have a wide range of temperature adaptation or they have a thermophilic evolutionary history in the modern cold deep-sea sediments of the Okhotsk Sea. The dominance of ammonia-oxidizing bacteria over AEA may indicate that bacteria play a significant role in nitrification in the Okhotsk Sea cold seep sediments.

Organic geochemical characterization of terrestrial source rocks of the Triassic Madygen formation (Southern Tien Shan, Kyrgyzstan)

Energy Technology Data Exchange (ETDEWEB)

Berner, U.; Scheeder, G.; Kus, J. [Section Geochemistry of Petroleum and Coal, BGR, Hannover (Germany); Voigt, S.; Schneider, J.W. [Geological Inst., TU Bergakademic Freiberg (Germany)

2009-09-15

Along the northern foothills of the Turkestan-Alai Range (SW Kyrgyzstan), a 1000 to 1500m thick succession of Mesozoic deposits is exposed recording regional changes of the paleo-landscape during Triassic to Cretaceous times. Detailed litho- and biofacies analyses, conducted by the TU Bergakademie Freiberg since 2006, provided for the first time a nearly complete columnar section of the continental Triassic Madygen Formation of Kyrgyzstan. Organic petrographical and organic geochemical methods (including RockEval pyrolyses, and biomarker analyses) have been applied to a suite of terrestrial sedimentary rocks of Triassic age with the intention to identify the depositional environment. Our investigations suggest that the potential source rocks of the terrestrial pluvial Madygen Formation might generate predominantly gaseous hydrocarbons at higher maturities. (orig.)

Reverse transcriptase directs viral evolution in a deep ocean methane seep

Science.gov (United States)

Paul, B. G.; Bagby, S. C.

2013-12-01

Deep ocean methane seeps are sites of intense microbial activity, with complex communities fueled by aerobic and anaerobic methanotrophy. Methane consumption in these communities has a substantial impact on the global carbon cycle, yet little is known about their evolutionary history or their likely evolutionary trajectories in a warming ocean. As in other marine systems, viral predation and virally mediated horizontal gene transfer are expected to be major drivers of evolutionary change in these communities; however, the host cells' resistance to cultivation has impeded direct study of the viral population. We conducted a metagenomic study of viruses in the anoxic sediments of a deep methane seep in the Santa Monica Basin in the Southern California Bight. We retrieved 1660 partial viral genomes, tentatively assigning 1232 to bacterial hosts and 428 to archaea. One abundant viral genome, likely hosted by Clostridia species present in the sediment, was found to encode a diversity-generating retroelement (DGR), a module for reverse transcriptase-mediated directed mutagenesis of a distal tail fiber protein. While DGRs have previously been described in the viruses of human pathogens, where diversification of viral tail fibers permits infection of a range of host cell types, to our knowledge this is the first description of such an element in a marine virus. By providing a mechanism for massively broadening potential host range, the presence of DGRs in these systems may have a major impact on the prevalence of virally mediated horizontal gene transfer, and even on the phylogenetic distances across which genes are moved.

Seawater capacitance – a promising proxy for mapping and characterizing drifting hydrocarbon plumes in the deep ocean

Directory of Open Access Journals (Sweden)

J. A. Fleming

2012-12-01

Full Text Available Hydrocarbons released into the deep ocean are an inevitable consequence of natural seep, seafloor drilling, and leaking wellhead-to-collection-point pipelines. The Macondo 252 (Deepwater Horizon well blowout of 2010 was even larger than the Ixtoc event in the Gulf of Campeche in 1979. History suggests it will not be the last accidental release, as deepwater drilling expands to meet an ever-growing demand. For those who must respond to this kind of disaster, the first line of action should be to know what is going on. This includes knowing where an oil plume is at any given time, where and how fast it is moving, and how it is evolving or degrading. We have experimented in the laboratory with induced polarization as a method to track hydrocarbons in the seawater column and find that finely dispersed oil in seawater gives rise to a large distributed capacitance. From previous sea trials, we infer this could potentially be used to both map and characterize oil plumes, down to a ratio of less than 0.001 oil-to-seawater, drifting and evolving in the deep ocean. A side benefit demonstrated in some earlier sea trials is that this same approach in modified form can also map certain heavy placer minerals, as well as communication cables, pipelines, and wrecks buried beneath the seafloor.

Carbon Isotope Analyses of Individual Hydrocarbon Molecules in Bituminous Coal, Oil Shale and Murchison Meteorite

Directory of Open Access Journals (Sweden)

Kyoungsook Kim

1998-06-01

Full Text Available To study the origin of organic matter in meteorite, terrestrial rocks which contain organic compounds similar to the ones found in carbonaceous chondrites are studied and compared with Murchison meteorite. Hydrocarbon molecules were extracted by benzene and methanol from bituminous coal and oil shale and the extracts were partitioned into aliphatic, aromatic, and polar fractions by silica gel column chromatography. Carbon isotopic ratios in each fractions were analysed by GC-C-IRMS. Molecular compound identifications were carried by GC-MS Engine. Bituminous coal and oil shale show the organic compound composition similar to that of meteorite. Oil shale has a wide range of δ(13C, -20.1%_0 - -54.4%_0 compared to bituminous coal, -25.2%_0 - -34.3%_0. Delta values of several molecular compounds in two terrestrial samples are different. They show several distinct distributions in isotopic ratios compared to those of meteorite; Murchison meteorite has a range of δ(13C from -13%_0 to +30%_0. These results provide interpretation for the source and the formation condition of each rock, in particular alteration and migration processes of organic matter. Especially, they show an important clue whether some hydrocarbon molecules observed in meteorite are indigenous or not.

Methane emission and consumption at a North Sea gas seep (Tommeliten area

Directory of Open Access Journals (Sweden)

H. Niemann

2005-01-01

Full Text Available The Tommeliten seepage area is part of the Greater Ekofisk area, which is situated above the Tommeliten Delta salt diapir in the central North Sea (56°29.90' N, 2°59.80' E, Norwegian Block 1/9, 75 m water depth. Here, cracks in a buried marl horizon allow methane to migrate into overlying clay-silt and sandy sediments. Hydroacoustic sediment echosounding showed several venting spots coinciding with the apex of marl domes where methane is released into the water column and potentially to the atmosphere. In the vicinity of the gas seeps, sea floor observations showed small mats of giant sulphide-oxidizing bacteria above patches of black sediments as well as carbonate crusts, which are exposed 10 to 50 cm above seafloor forming small reefs. These Methane-Derived Authigenic Carbonates (MDACs contain 13C-depleted, archaeal lipids indicating previous gas seepage and AOM activity. High amounts of sn2-hydroxyarchaeol relative to archaeol and low abundances of biphytanes in the crusts give evidence that ANaerobic MEthane-oxidising archaea (ANME of the phylogenetic cluster ANME-2 were the potential mediators of Anaerobic Oxidation of Methane (AOM at the time of carbonate formation. Small pieces of MDACs were also found subsurface at about 1.7 m sediment depth, associated with the AOM zone. This zone is characterized by elevated AOM and Sulphate Reduction (SR rates, increased concentrations of 13C-depleted tetraether derived biphytanes, and specific bacterial Fatty Acids (FA. Further biomarker and 16S rDNA based analyses of this horizon give evidence that AOM is mediated by archaea belonging to the ANME-1b group and Sulphate Reducing Bacteria (SRB most likely belonging to the Seep-SRB1 cluster. The zone of active methane consumption was restricted to a distinct horizon of about 20 cm. Concentrations of 13C-depleted lipid biomarkers (e.g. 500 ng g-dw−1 biphythanes, 140 ng g-dw−1 fatty acid ai-C15:0, cell numbers (1.5×108 cells cm−3, AOM and SR

Aromatic hydrocarbons

International Nuclear Information System (INIS)

Roder, M.

1985-01-01

Papers dealing with radiolysis of aromatic hydrocarbons of different composition (from benzene to terphenyls and hydrocarbons with condensed rings) as well as their mixtures (with alkanes, alkenes, other aromatic hydrocarbons) are reviewed. High radiation stability of aromatic hydrocarbons in condensed phases associated with peculiarities of molecular structure of compounds is underlined. Mechanisms of radiolytic processes, vaues of product yields are considered

Inventory, distribution, and origin of aliphatic and polyaromatic hydrocarbons in sea water, the surface microlayer, and the aerosols in the tropical Eastern Atlantic

Energy Technology Data Exchange (ETDEWEB)

Marty, J C; Saliot, A; Tissier, M J

1978-03-20

Hydrocarbons have been analyzed in several samples from ''Midlante'' cruise, Cape Verde islands-Canary islands, in the Eastern tropical Atlantic: subsurface water, sea surface microlayer collected by a metallic screen and aerosols collected by filtration of large air volumes at about 12 m. above the sea surface. Detailed analysis of aliphatic and polyaromatic hydrocarbons has been made by computerized gas chromatography/mass spectrometry. This study of the air/sea interface indicates a discontinuity in hydrocarbon composition between the underlying water and the microlayer and a similarity between the surface microlayer and the aerosols. The origin of the collected aerosols is essentially marine with a minor terrestrial contribution. The hydrocarbon pattern shows that, superimposed on the typical marine components, a contribution from smokes of natural and industrial origin and/or from pollution associated with crude oil sea slicks is present.

Tectono-Stratigraphy of the Seeps on the Guaymas Basin at the Sonora Margin, Gulf of California, Mexico

Science.gov (United States)

Figueroa Albornoz, L. J.; Mortera-Gutierrez, C. A.; Bandy, W. L.; Escobar-Briones, E. G.; Godfroy, A.; Fouquet, Y.

2013-05-01

Recently several hydrothermal and gas seeps systems has been located precisely at the Sonora margin within the Guaymas Basin (GB), Gulf of California. Since late 1970's , several marine studies had reported two main hydrothermal systems in the Guaymas Rift (one at the Northern Rift, and other at the Southern Rift) and a cold seeps system at the Satellite Basin in the Sonora-margin lower edge. During the campaign BIG10, onboard the IFREMER vessel, NO L'Atalante, the EM122 echo-sounder log more than 30,000 water column acoustic images, which allows us to create a data base of the bubble plumes active systems on the northern part of the GB and the Sonora Margin. These plumes are the expression on the water column of an active seeps site during the cruise time. These images document the presence of the cold seep activity around the scarp of the Guaymas Transform Fault (GTF), and within the Satellite Basin. Few active plumes are first located off-axis, on both sides of the Northern Rift. Although it is not observed any plume within NR. Sub-bottom profiles and bathymetric data logged during the campaign GUAYRIV10, onboard the UNAM vessel, BO EL PUMA, are analyzed to determine the shallow tectonic-stratigraphy of GB near the Sonora Margin. We analyze 17 high-resolution seismic profiles (13 with NE-SW strike and 3 with NW-SE strike). From this data set, the continental shelf stratigraphy at the Sonora Margin tilts toward the slope, showing 3 low angle unconformities due to tectonics and slope angle changes. The strata slope changes angle up to 60°. However, the constant trans-tension shear along the GTF causes gravitation instability on the slope, generating a few submarine landslides close to the Northern Rift, and the rotation of blocks, tilting toward the shelf. To the north, the GTF splits in two fault escarpments, forming a narrow pull-apart basin, known as Satellite Basin. The submarine canyon from the Sonora River flows through the Satellite Basin into the GB

A molecular gut content study of Themisto abyssorum (Amphipoda) from Arctic hydrothermal vent and cold seep systems.

Science.gov (United States)

Olsen, Bernt Rydland; Troedsson, Christofer; Hadziavdic, Kenan; Pedersen, Rolf B; Rapp, Hans Tore

2014-08-01

The use of DNA as a marker for prey inside the gut of predators has been instrumental in further understanding of known and unknown interactions. Molecular approaches are in particular useful in unavailable environments like the deep sea. Trophic interactions in the deep sea are difficult to observe in situ, correct deep-sea experimental laboratory conditions are difficult to obtain, animals rarely survive the sampling, or the study organisms feed during the sampling due to long hauls. Preliminary studies of vent and seep systems in the Nordic Seas have identified the temperate-cold-water pelagic amphipod Themisto abyssorum as a potentially important predator in these chemosynthetic habitats. However, the prey of this deep-sea predator is poorly known, and we applied denaturing high performance liquid chromatography (DHPLC) to investigate the predator-prey interactions of T. abyssorum in deep-water vent and seep systems. Two deep-water hydrothermally active localities (The Jan Mayen and Loki's Castle vent fields) and one cold seep locality (The Håkon Mosby mud volcano) in the Nordic Seas were sampled, genomic DNA of the stomachs of T. abyssorum was extracted, and 18S rDNA gene was amplified and used to map the stomach content. We found a wide range of organisms including micro-eukaryotes, metazoans and detritus. Themisto abyssorum specimens from Loki's Castle had the highest diversity of prey. The wide range of prey items found suggests that T. abyssorum might be involved in more than one trophic level and should be regarded as an omnivore and not a strict carnivore as have previously been suggested. © 2013 John Wiley & Sons Ltd.

Geological evolution, regional perspectives and hydrocarbon potential of the northwest Phu Khanh Basin, offshore Central Vietnam

DEFF Research Database (Denmark)

Fyhn, Michael Bryld Wessel; Nielsen, Lars H.; Boldreel, Lars Ole

2009-01-01

seeps are found at Dam Thi Nai, immediately landward of the basin. Geochemical analyses of the oil seeps indicate the existence of at least two early to peak mature source rocks. Maturation modelling, combined with the seismic analysis, suggests the likely presence of oil kitchens 40-50km downdip...

Patterns and variability in geochemical signatures and microbial activity within and between diverse cold seep habitats along the lower continental slope, Northern Gulf of Mexico

Science.gov (United States)

Bowles, Marshall; Hunter, Kimberley S.; Samarkin, Vladimir; Joye, Samantha

2016-07-01

We collected 69 sediment cores from distinct ecological and geological settings along the deep slope in the Northern Gulf of Mexico to evaluate whether specific geochemical- or habitat-related factors correlated with rates of microbial processes and geochemical signatures. By collecting replicate cores from distinct habitats across multiple sites, we illustrate and quantify the heterogeneity of cold seep geochemistry and microbial activity. These data also document the factors driving unique aspects of the geochemistry of deep slope gas, oil and brine seeps. Surprisingly little variation was observed between replicate (n=2-5) cores within sites for most analytes (except methane), implying that the common practice of collecting one core for geochemical analysis can capture the signature of a habitat in most cases. Depth-integrated concentrations of methane, dissolved inorganic carbon (DIC), and calcium were the predominant geochemical factors that correlated with a site's ecological or geological settings. Pore fluid methane concentration was related to the phosphate and DIC concentration, as well as to rates of sulfate reduction. While distinctions between seep habitats were identified from geochemical signatures, habitat specific geochemistry varied little across sites. The relative concentration of dissolved inorganic nitrogen versus phosphorus suggests that phosphorus availability limits biomass production at cold seeps. Correlations between calcium, chloride, and phosphate concentrations were indicative of brine-associated phosphate transport, suggesting that in addition to the co-migration of methane, dissolved organic carbon, and ammonium with brine, phosphate delivery is also associated with brine advection.

The phase transition of methane caused by pressure change during its seeping up from seepage, revealed by video observation and acoustic reflection data

Science.gov (United States)

Aoyama, C.

2017-12-01

Methane plumes often exist in the vicinity sea area where shallow type methane hydrates are extracted and they are observed as images displayed on monitors of multi-beam sonar and echo sounder onboard, where methane hydrates are expected at sea bottom on ROV observation data. The hydrates are generally considered to be generated in shallow depths below the sea floor. In this study, author examined annual amount of methane dissolving into seawater by measuring the amount of plume in order to make a quantification of dissolving methane from seafloor. Measurement procedure is plume exploration using multi-beam and quantitative echo sounder , submerge ROV to gushing point at seafloor , calculate the rising speed of methane plumes and examine the phases by monitoring seeping plumes from seafloor with high-definition camera. Components of seeping plumes were defined as methane hydrate particles based on the result by measuring water temperature. From this procedure, it can be concluded that the minimum rising speed of methane hydrate particles from gushing point is 1.6×10-1(m/s) and the maximum of 2.0×10-1(m/s) indicating a difference of more than ten times the gaseous theoretical value of 2.74(m/s). This speed is theoretically closer to the solid speed of the material with physical property similar to hydrates, which is 3.05×10-1 (m/s). Therefore, it can be determined that those particles are in the solid state, immediately above seafloor. To measure the amount of plumes seeping from gushing points funnel-shaped instruments with 20cm diameter opening were used to collect methane plumes in this sea area. This was performed in three different gushing points. As a result, 300ml of methane plume was collected in 643 seconds. Assuming that gushing points exist evenly in the sea area, the annual amount of methane gas seeping from these points will be 7.7×105m3 /per m2. Result shows a large quantity of methane seeping from seafloor into the water. This data is an important

Hydrocarbons in Deep-Sea Sediments following the 2010 Deepwater Horizon Blowout in the Northeast Gulf of Mexico.

Directory of Open Access Journals (Sweden)

Isabel C Romero

Full Text Available The Deepwater Horizon (DWH spill released 4.9 million barrels of oil into the Gulf of Mexico (GoM over 87 days. Sediment and water sampling efforts were concentrated SW of the DWH and in coastal areas. Here we present geochemistry data from sediment cores collected in the aftermath of the DWH event from 1000-1500 m water depth in the DeSoto Canyon, NE of the DWH wellhead. Cores were analyzed at high-resolution (at 2 mm and 5 mm intervals in order to evaluate the concentration, composition and input of hydrocarbons to the seafloor. Specifically, we analyzed total organic carbon (TOC, aliphatic, polycyclic aromatic hydrocarbon (PAHs, and biomarker (hopanes, steranes, diasteranes compounds to elucidate possible sources and transport pathways for deposition of hydrocarbons. Results showed higher hydrocarbon concentrations during 2010-2011 compared to years prior to 2010. Hydrocarbon inputs in 2010-2011 were composed of a mixture of sources including terrestrial, planktonic, and weathered oil. Our results suggest that after the DWH event, both soluble and highly insoluble hydrocarbons were deposited at enhanced rates in the deep-sea. We proposed two distinct transport pathways of hydrocarbon deposition: 1 sinking of oil-particle aggregates (hydrocarbon-contaminated marine snow and/or suspended particulate material, and 2 advective transport and direct contact of the deep plume with the continental slope surface sediments between 1000-1200 m. Our findings underline the complexity of the depositional event observed in the aftermath of the DWH event in terms of multiple sources, variable concentrations, and spatial (depth-related variability in the DeSoto Canyon, NE of the DWH wellhead.

Estimation of past intermittent methane seep activity using radiocarbon dating of Calyptogena shells in the eastern Nankai subduction zone

Science.gov (United States)

Yagasaki, K.; Ashi, J.; Yokoyama, Y.; Miyairi, Y.; Kuramoto, S.

2013-12-01

Radioisotope carbon dating samples from the deep ocean has always been a difficult phenomenon due to the carbon offset present. This research presents a way of utilizing such method to date shell samples in order to study past fault activities. The research presented will be based on the preliminary data collected thus far. The Nankai and the Tokai regions are common areas for cold seeps, where seepage of hydrogen sulfide and methane rich fluid occurs. These various substances encourage the growth of Calyptogena colonies to flourish at these sites. Cold seeps generally occur at tectonically active continental margins and are mostly ephemeral. This suggests that the cold seep events are possibly influenced by the tectonic activity during the plate divergence. In 1997, a submersible dive by Shinkai 2000 discovered an unusually large Calyptogena colony ranging over 200 m2 off Daini Tenryu Knoll. Majority of the shells were fossilized with few live shells remaining. It is assumed that past tectonic events in the region may have caused a high flux of methane fluid or gas to be released, making it possible to support such a vast scale colony to survive until their eventual death. Previous attempt to reconstruct the cold seep activity history through amino acid racemisation dating revealed two different age grouped shells. Further data using a different method is required to prove its reliability, as acid racemization dating technique can easily be affected by seawater temperature changes and microbial activity. This consequently alters the protein structure of the sample and its overall age. As 14C radioisotope dating is not affected by temperature change, it will provide additional information to the accuracy of the acid racemisation dating of the shell. However, the possibility of contamination is likely due to the shells incorporating older carbon from the sediments during their early stages of growth. The old carbon value can be calculated by subtracting the formerly

Families of miocene monterey crude oil, seep, and tarball samples, coastal California

Science.gov (United States)

Peters, K.E.; Hostettler, F.D.; Lorenson, T.D.; Rosenbauer, R.J.

2008-01-01

Biomarker and stable carbon isotope ratios were used to infer the age, lithology, organic matter input, and depositional environment of the source rocks for 388 samples of produced crude oil, seep oil, and tarballs to better assess their origins and distributions in coastal California. These samples were used to construct a chemometric (multivariate statistical) decision tree to classify 288 additional samples. The results identify three tribes of 13C-rich oil samples inferred to originate from thermally mature equivalents of the clayey-siliceous, carbonaceous marl and lower calcareous-siliceous members of the Monterey Formation at Naples Beach near Santa Barbara. An attempt to correlate these families to rock extracts from these members in the nearby COST (continental offshore stratigraphic test) (OCS-Cal 78-164) well failed, at least in part because the rocks are thermally immature. Geochemical similarities among the oil tribes and their widespread distribution support the prograding margin model or the banktop-slope-basin model instead of the ridge-and-basin model for the deposition of the Monterey Formation. Tribe 1 contains four oil families having geochemical traits of clay-rich marine shale source rock deposited under suboxic conditions with substantial higher plant input. Tribe 2 contains four oil families with traits intermediate between tribes 1 and 3, except for abundant 28,30-bisnorhopane, indicating suboxic to anoxic marine marl source rock with hemipelagic input. Tribe 3 contains five oil families with traits of distal marine carbonate source rock deposited under anoxic conditions with pelagic but little or no higher plant input. Tribes 1 and 2 occur mainly south of Point Conception in paleogeographic settings where deep burial of the Monterey source rock favored petroleum generation from all three members or their equivalents. In this area, oil from the clayey-siliceous and carbonaceous marl members (tribes 1 and 2) may overwhelm that from the lower

Seismic imaging of the Formosa Ridge cold seep site offshore of southwestern Taiwan

Science.gov (United States)

Hsu, Ho-Han; Liu, Char-Shine; Morita, Sumito; Tu, Shu-Lin; Lin, Saulwood; Machiyama, Hideaki; Azuma, Wataru; Ku, Chia-Yen; Chen, Song-Chuen

2017-12-01

Multi-scale reflection seismic data, from deep-penetration to high-resolution, have been analyzed and integrated with near-surface geophysical and geochemical data to investigate the structures and gas hydrate system of the Formosa Ridge offshore of southwestern Taiwan. In 2007, dense and large chemosynthetic communities were discovered on top of the Formosa Ridge at water depth of 1125 m by the ROV Hyper-Dolphin. A continuous and strong BSR has been observed on seismic profiles from 300 to 500 ms two-way-travel-time below the seafloor of this ridge. Sedimentary strata of the Formosa Ridge are generally flat lying which suggests that this ridge was formed by submarine erosion processes of down-slope canyon development. In addition, some sediment waves and mass wasting features are present on the ridge. Beneath the cold seep site, a vertical blanking zone, or seismic chimney, is clearly observed on seismic profiles, and it is interpreted to be a fluid conduit. A thick low velocity zone beneath BSR suggests the presence of a gas reservoir there. This "gas reservoir" is shallower than the surrounding canyon floors along the ridge; therefore as warm methane-rich fluids inside the ridge migrate upward, sulfate carried by cold sea water can flow into the fluid system from both flanks of the ridge. This process may drive a fluid circulation system and the active cold seep site which emits both hydrogen sulfide and methane to feed the chemosynthetic communities.

Effects of ocean acidification on the shells of four Mediterranean gastropod species near a CO2 seep.

Science.gov (United States)

Duquette, Ashley; McClintock, James B; Amsler, Charles D; Pérez-Huerta, Alberto; Milazzo, Marco; Hall-Spencer, Jason M

2017-11-30

Marine CO 2 seeps allow the study of the long-term effects of elevated pCO 2 (ocean acidification) on marine invertebrate biomineralization. We investigated the effects of ocean acidification on shell composition and structure in four ecologically important species of Mediterranean gastropods (two limpets, a top-shell snail, and a whelk). Individuals were sampled from three sites near a volcanic CO 2 seep off Vulcano Island, Italy. The three sites represented ambient (8.15pH), moderate (8.03pH) and low (7.73pH) seawater mean pH. Shell mineralogy, microstructure, and mechanical strength were examined in all four species. We found that the calcite/aragonite ratio could vary and increased significantly with reduced pH in shells of one of the two limpet species. Moreover, each of the four gastropods displayed reductions in either inner shell toughness or elasticity at the Low pH site. These results suggest that near-future ocean acidification could alter shell biomineralization and structure in these common gastropods. Copyright © 2017 Elsevier Ltd. All rights reserved.

The microbial ferrous wheel in a neutral pH groundwater seep

Directory of Open Access Journals (Sweden)

Eric eRoden

2012-05-01

Full Text Available Evidence for microbial Fe redox cycling was documented in a circumneutral pH groundwater seep near Bloomington, Indiana. Geochemical and microbiological analyses were conducted at two sites, a semi-consolidated microbial mat and a floating puffball structure. In situ voltammetric microelectrode measurements revealed steep opposing gradients of O2 and Fe(II at both sites, similar to other groundwater seep and sedimentary environments known to support microbial Fe redox cycling. The puffball structure showed an abrupt increase in dissolved Fe(II just at its surface (~ 5 cm depth, suggesting an internal Fe(II source coupled to active Fe(III reduction. MPN enumerations detected microaerophilic Fe(II-oxidizing bacteria (FeOB and dissimilatory Fe(III-reducing bacteria (FeRB at densities of 102-105 cells mL-1 in samples from both sites. In vitro Fe(III reduction experiments revealed the potential for immediate reduction (no lag period of native Fe(III oxides. Conventional full-length 16S rRNA gene clone libraries were compared withhigh throughput barcode sequencing of the V1, V4 or V6 variable regions of 16S rRNA genes in order to evaluate the extent to which new sequencing approaches could provide enhanced insight into the composition of Fe redox cycling microbial community structure. The composition of the clone libraries suggested a lithotroph-dominated microbial community centered around taxa related to known FeOB (e.g. Gallionella, Sideroxydans, Aquabacterium. Sequences related to recognized FeRB (e.g. Rhodoferax, Aeromonas, Geobacter, Desulfovibrio were also well represented. Overall, sequences related to known FeOB and FeRB accounted for 88 and 59% of total clone sequences in the mat and puffball libraries, respectively. Taxa identified in the barcode libraries showed partial overlap with the clone libraries, but were not always consistent across different variable regions and sequencing platforms. However, the barcode libraries provided

Distribution, activity and function of short-chain alkane degrading phylotypes in hydrothermal vent sediments

Science.gov (United States)

Adams, M. M.; Joye, S. B.; Hoarfrost, A.; Girguis, P. R.

2012-12-01

Global geochemical analyses suggest that C2-C4 short chain alkanes are a common component of the utilizable carbon pool in deep-sea sediments worldwide and have been found in diverse ecosystems. From a thermodynamic standpoint, the anaerobic microbial oxidation of these aliphatic hydrocarbons is more energetically yielding than the anaerobic oxidation of methane (AOM). Therefore, the preferential degradation of these hydrocarbons may compete with AOM for the use of oxidants such as sulfate, or other potential oxidants. Such processes could influence the fate of methane in the deep-sea. Sulfate-reducing bacteria (SRB) from hydrocarbon seep sediments of the Gulf of Mexico and Guaymas Basin have previously been enriched that anaerobically oxidize short chain alkanes to generate CO2 with the preferential utilization of 12C-enriched alkanes (Kniemeyer et al. 2007). Different temperature regimens along with multiple substrates were tested and a pure culture (deemed BuS5) was isolated from mesophilic enrichments with propane or n-butane as the sole carbon source. Through comparative sequence analysis, strain BuS5 was determined to cluster with the metabolically diverse Desulfosarcina / Desulfococcus cluster, which also contains the SRB found in consortia with anaerobic, methane-oxidizing archaea in seep sediments. Enrichments from a terrestrial, low temperature sulfidic hydrocarbon seep also corroborated that propane degradation occurred with most bacterial phylotypes surveyed belonging to the Deltaproteobacteria, particularly Desulfobacteraceae (Savage et al. 2011). To date, no microbes capable of ethane oxidation or anaerobic C2-C4 alkane oxidation at thermophilic temperature have been isolated. The sediment-covered, hydrothermal vent systems found at Middle Valley (Juan de Fuca Ridge, eastern Pacific Ocean) are a prime environment for investigating mesophilic to thermophilic anaerobic oxidation of short-chain alkanes, given the elevated temperatures and dissolved

Microbial processes and communities in sediment samples along a transect across the Lusi mud volcano, Indonesia

Science.gov (United States)

Krueger, Martin; Straaten, Nontje; Mazzini, Adriano

2015-04-01

The Lusi eruption represents one of the largest ongoing sedimentary hosted geothermal systems. This eruption started in 2006 following to a 6.3 M earthquake that stroke Java Island. Since then it has been spewing boiling mud from a central crater with peaks reaching 180.000 m3 per day. Today an area of about 8 km2 is covered by locally dried mud breccia where a network of hundreds of satellite seeping pools is active. Numerous investigations focused on the study of offshore microbial colonies that commonly thrive at offshore methane seeps and mud volcanoes, however very little has been done for onshore seeping structures. Lusi represents a unique opportunity to complete a comprehensive study of onshore microbial communities fed by the seepage of CH4 and CO2 as well as of heavier liquid hydrocarbons originating from several km below the surface. We conducted a sampling campaign at the Lusi site collecting samples of fresh mud close to the erupting crater using a remote controlled drone. In addition we completed a transect towards outer parts of the crater to collect older, weathered samples for comparison. In all samples active microorganisms were present. The highest activities for CO2 and CH4 production as well as for CH4 oxidation and hydrocarbon degradation were observed in medium-age mud samples collected roughly in the middle of the transect. Rates for aerobic methane oxidation were high, as was the potential of the microbial communities to degrade hydrocarbons (oils, alkanes, BTEX tested). The data suggests a transition of microbial populations from an anaerobic, hydrocarbon-driven metabolism in fresher samples from center or from small seeps to more generalistic, aerobic microbial communities in older, more consolidated sediments. Currently, the microbial communities in the different sediment samples are analyzed using quantitative PCR and T-RFLP combined with MiSeq sequencing. This study represents an initial step to better understand onshore seepage

Digital video collected during Pisces II submersible dive 880018 by Bureau of Ocean Energy Management (BOEM) in the Gulf of Mexico on 1988-07-28 (NCEI Accession 0164789)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This Archival Information Package (AIP) contains videographic data of ocean floor biology and geology at a suspected hydrocarbon seep site in the Gulf of Mexico,...

A statistical approach to the interpretation of aliphatic hydrocarbon distributions in marine sediments

Science.gov (United States)

Rapp, J.B.

1991-01-01

Q-mode factor analysis was used to quantitate the distribution of the major aliphatic hydrocarbon (n-alkanes, pristane, phytane) systems in sediments from a variety of marine environments. The compositions of the pure end members of the systems were obtained from factor scores and the distribution of the systems within each sample was obtained from factor loadings. All the data, from the diverse environments sampled (estuarine (San Francisco Bay), fresh-water (San Francisco Peninsula), polar-marine (Antarctica) and geothermal-marine (Gorda Ridge) sediments), were reduced to three major systems: a terrestrial system (mostly high molecular weight aliphatics with odd-numbered-carbon predominance), a mature system (mostly low molecular weight aliphatics without predominance) and a system containing mostly high molecular weight aliphatics with even-numbered-carbon predominance. With this statistical approach, it is possible to assign the percentage contribution from various sources to the observed distribution of aliphatic hydrocarbons in each sediment sample. ?? 1991.

Evidence for Perchlorates and the Origin of Chlorinated Hydrocarbons Detected by SAM at the Rocknest Aeolian Deposit in Gale Crater

Science.gov (United States)

Glavin, Daniel P.; Freissinet, Caroline; Miller, Kristen E.; Eigenbrode, Jennifer L.; Brunner, Anna E.; Buch, Arnaud; Sutter, Brad; Archer, P. Douglas, Jr.; Atreya, Sushil K.; Brinckerhoff, William B.;

Mass transfer between waste canister and water seeping in rock fractures. Revisiting the Q-equivalent model

International Nuclear Information System (INIS)

Neretnieks, Ivars; Liu Longcheng; Moreno, Luis

2010-03-01

Models are presented for solute transport between seeping water in fractured rock and a copper canister embedded in a clay buffer. The migration through an undamaged buffer is by molecular diffusion only as the clay has so low hydraulic conductivity that water flow can be neglected. In the fractures and in any damaged zone seeping water carries the solutes to or from the vicinity of the buffer in the deposition hole. During the time the water passes the deposition hole molecular diffusion aids in the mass transfer of solutes between the water/buffer interface and the water at some distance from the interface. The residence time of the water and the contact area between the water and the buffer determine the rate of mass transfer between water and buffer. Simple analytical solutions are presented for the mass transfer in the seeping water. For complex migration geometries simplifying assumptions are made that allow analytical solutions to be obtained. The influence of variable apertures on the mass transfer is discussed and is shown to be moderate. The impact of damage to the rock around the deposition hole by spalling and by the presence of a cemented and fractured buffer is also explored. These phenomena lead to an increase of mass transfer between water and buffer. The overall rate of mass transfer between the bulk of the water and the canister is proportional to the overall concentration difference and inversely proportional to the sum of the mass transfer resistances. For visualization purposes the concept of equivalent flowrate is introduced. This entity can be thought as of the flowrate of water that will be depleted of its solute during the water passage past the deposition hole. The equivalent flowrate is also used to assess the release rate of radionuclides from a damaged canister. Examples are presented to illustrate how various factors influence the rate of mass transfer

Seasonal monitoring of deep-sea megabenthos in Barkley Canyon cold seep by internet operated vehicle (IOV.

Directory of Open Access Journals (Sweden)

Carolina Doya

Full Text Available Knowledge of the processes shaping deep-sea benthic communities at seasonal scales in cold-seep environments is incomplete. Cold seeps within highly dynamic regions, such as submarine canyons, where variable current regimes may occur, are particularly understudied. Novel Internet Operated Vehicles (IOVs, such as tracked crawlers, provide new techniques for investigating these ecosystems over prolonged periods. In this study a benthic crawler connected to the NEPTUNE cabled infrastructure operated by Ocean Networks Canada was used to monitor community changes across 60 m2 of a cold-seep area of the Barkley Canyon, North East Pacific, at ~890 m depth within an Oxygen Minimum Zone (OMZ. Short video-transects were run at 4-h intervals during the first week of successive calendar months, over a 14 month period (February 14th 2013 to April 14th 2014. Within each recorded transect video megafauna abundances were computed and changes in environmental conditions concurrently measured. The responses of fauna to environmental conditions as a proxy of seasonality were assessed through analysis of abundances in a total of 438 video-transects (over 92 h of total footage. 7698 fauna individuals from 6 phyla (Cnidaria, Ctenophora, Arthropoda, Echinodermata, Mollusca, and Chordata were logged and patterns in abundances of the 7 most abundant taxa (i.e. rockfish Sebastidae, sablefish Anoplopoma fimbria, hagfish Eptatretus stoutii, buccinids (Buccinoidea, undefined small crabs, ctenophores Bolinopsis infundibulum, and Scyphomedusa Poralia rufescens were identified. Patterns in the reproductive behaviour of the grooved tanner crab (Chionnecetes tanneri were also indicated. Temporal variations in biodiversity and abundance in megabenthic fauna was significantly influenced by variabilities in flow velocity flow direction (up or down canyon, dissolved oxygen concentration and month of study. Also reported here for the first time are transient mass aggregations of

Oil seepage polarimetric contrast analysis in a time series of TerraSAR-X images

OpenAIRE

de Macedo, Carina Regina; Nunziata, Ferdinando; Velotto, Domenico; Migliaccio, Maurizio

2017-01-01

Natural hydrocarbon seeps are broadly distributed across the Gulf of Mexico. Such seeps emit oil and gas into the water column, increasing the phytoplankton biomass and impacting regionally the productivity, carbon and nutrient cycling [1]. A fraction of this oil reaches to the sea surface and can be detected by SAR data. Although the ability of SAR data to detect oil features present in ocean's surface is wide exploited in the literature, it is known that the detection of those features is a...

Classification of sea-floor features associated with methane seeps along the Gulf of Cádiz continental margin

Science.gov (United States)

León, Ricardo; Somoza, Luis; Medialdea, Teresa; Maestro, Adolfo; Díaz-del-Río, Victor; Fernández-Puga, María del Carmen

2006-06-01

Based on recently gathered swath-bathymetry, high- to ultra-high-resolution seismic, and underwater camera data, along with dredging and coring samples, this paper examines the relationship between sea-floor features and the nature of hydrocarbon-enriched fluid and gas leaks from degassing of deeply buried sediments along the continental margin of the Gulf of Cádiz (eastern Central Atlantic). A classification into three main groups is proposed on the basis of the morphology and nature of deposits: (1) mud volcanoes, (2) methane-derived authigenic carbonates (MDAC) mounds, and (3) crater-like pockmarks. Mud volcanoes are, topographically, cone-shaped sea-floor edifices, built up from catastrophic mud and fluid degassing, intercalated with periods of inactivity. So far more than 25 mud volcanoes have been discovered in the Gulf of Cádiz, named in memory of deceased colleagues (e.g., Ginsburg and Baraza), or researchers' birth places (e.g. Faro, Cibeles, Almazán, San Petersburgh, Yuma, Rabat, Bonjardim, Coruña, Gades). These structures range from 800 to 2500 m in diameter and tower 150-300 m above the seabed. The volcanoes consistently feature a well-defined outer ring or circular terrace and an inner dome. All mud volcanoes are built up of episodes of mud-breccia flows, intercalated with deep-current deposits, with evident indications of gas saturation: degassing structures, a strong H 2S smell, and chemosynthetic fauna (such as Pogonophora sp. tube worms and Calyptogena sp.). Commonly observed carbonate crusts and slabs overlying some mud volcanoes are thought to have been formed by slow, diffuse venting during periods of inactivity or slower rates of fluid venting following the ejection of mud. A "fermentation" process, the result of microbial-mediated oxidation of hydrocarbon-enriched fluids, seems to play an important role in the growth of large deep-water carbonate mounds and chimneys during periods of low methane-seep fluid pressure. More than 400 crater

Leg tendon glands in male bumblebees ( Bombus terrestris): structure, secretion chemistry, and possible functions

Science.gov (United States)

Jarau, Stefan; Žáček, Petr; Šobotník, Jan; Vrkoslav, Vladimír; Hadravová, Romana; Coppée, Audrey; Vašíčková, Soňa; Jiroš, Pavel; Valterová, Irena

2012-12-01

Among the large number of exocrine glands described in bees, the tarsal glands were thought to be the source of footprint scent marks. However, recent studies showed that the compounds used for marking by stingless bees are secreted by leg tendon instead of tarsal glands. Here, we report on the structure of leg tendon glands in males of Bombus terrestris, together with a description of the chemical composition of their secretions and respective changes of both during the males' lives. The ultrastructure of leg tendon glands shows that the secretory cells are located in three independent regions, separated from each other by unmodified epidermal cells: in the femur, tibia, and basitarsus. Due to the common site of secretion release, the organ is considered a single secretory gland. The secretion of the leg tendon glands of B. terrestris males differs in its composition from those of workers and queens, in particular by (1) having larger proportions of compounds with longer chain lengths, which we identified as wax esters; and (2) by the lack of certain hydrocarbons (especially long chain dienes). Other differences consist in the distribution of double bond positions in the unsaturated hydrocarbons that are predominantly located at position 9 in males but distributed at seven to nine different positions in the female castes. Double bond positions may change chemical and physical properties of a molecule, which can be recognized by the insects and, thus, may serve to convey specific information. The function of male-specific compounds identified from their tendon glands remains elusive, but several possibilities are discussed.

Diversity and distribution of eukaryotic microbes in and around a brine pool adjacent to the Thuwal cold seeps in the Red Sea

KAUST Repository

Wang, Yong; Zhang, Wei Peng; Cao, Hui Luo; Shek, Chun Shum; Tian, Ren Mao; Wong, Yue Him; Batang, Zenon B.; Al-Suwailem, Abdulaziz M.; Qian, Pei-Yuan

2014-01-01

abundant species highly similar to invertebrate gregarine parasites identified in different oxygen-depleted sediments. Therefore, the present findings support the uniqueness of some microbial eukaryotic groups in this cold seep brine system. 2014 Wang

Hydrocarbon degassing of the earth and origin of oil-gas fields (isotope-geochemical and geodynamic aspects)

Science.gov (United States)

Valyaev, Boris; Dremin, Ivan

2016-04-01

More than half a century ago, Academician PN Kropotkin substantiated the relationship of the formation and distribution of oil and gas fields with the processes of emanation hydrocarbon degassing of the Earth. Over the years, the concept of PN Kropotkin received further development and recognition of studies based on new factual material. Of particular importance are the following factors: a) the results of studies on global and regional uneven processes of traditional oil and gas and the role of deep faults in controlling the spread of oil and gas fields; b) the results of the research on gigantic volumes and localization of the discharges of hydrocarbon fluids (mud volcanoes, seeps) on land and into the atmosphere and through the bottom of the World ocean; c) the results of the studies on grand volumes of the spread of unconventional hydrocarbon resources in their non-traditional fields, especially on near-surface interval of unconventional oil and gas accumulation with gas hydrates, heavy oil and bitumen, as well as extraordinary resources of oil and gas in the shale and tight rocks. Deep mantle-crust nature of oil and gas in traditional and nontraditional deposits thus received further substantiation of geological and geophysical data and research results. However, isotopic and geochemical data are still interpreted in favor of the concept of the genesis of oil and gas in the processes of thermal catalytic conversion of organic matter of sedimentary rocks, at temperatures up to 200°C. In this report an alternative interpretation of the isotope carbon-hydrogen system (δ13C-δD) for gas and of oil deposits, isotope carbon system for methane and carbon dioxide (δ13C1-δ13C0) will be presented. An alternative interpretation will also be presented for the data on carbon-helium isotope geochemical system for oil and gas fields, volcanoes and mud volcanoes. These constructions agree with the geological data on the nature of deep hydrocarbon fluids involved in the

Energy transfer in the Congo deep-sea fan: From terrestrially-derived organic matter to chemosynthetic food webs

Science.gov (United States)

Pruski, A. M.; Decker, C.; Stetten, E.; Vétion, G.; Martinez, P.; Charlier, K.; Senyarich, C.; Olu, K.

2017-08-01

Large amounts of recent terrestrial organic matter (OM) from the African continent are delivered to the abyssal plain by turbidity currents and accumulate in the Congo deep-sea fan. In the recent lobe complex, large clusters of vesicomyid bivalves are found all along the active channel in areas of reduced sediment. These soft-sediment communities resemble those fuelled by chemoautotrophy in cold-seep settings. The aim of this study was to elucidate feeding strategies in these macrofaunal assemblages as part of a greater effort to understand the link between the inputs of terrestrially-derived OM and the chemosynthetic habitats. The biochemical composition of the sedimentary OM was first analysed in order to evaluate how nutritious the available particulate OM is for the benthic macrofauna. The terrestrial OM is already degraded when it reaches the final depositional area. However, high biopolymeric carbon contents (proteins, carbohydrates and lipids) are found in the channel of the recent lobe complex. In addition, about one to two thirds of the nitrogen can be assigned to peptide-like material. Even if this soil-derived OM is poorly digestible, turbiditic deposits contain such high amounts of organic carbon that there is enough biopolymeric carbon and proteacinous nitrogen to support dense benthic communities that contrast with the usual depauperate abyssal plains. Stable carbon and nitrogen isotopes and fatty acid biomarkers were then used to shed light on the feeding strategies allowing the energy transfer from the terrestrial OM brought by the turbidity currents to the abyssal food web. In the non-reduced sediment, surface detritivorous holothurians and suspension-feeding poriferans rely on detritic OM, thereby depending directly on the turbiditic deposits. The sulphur-oxidising symbiont bearing vesicomyids closely depend on the reprocessing of OM with methane and sulphide as final products. Their carbon and nitrogen isotopic signatures vary greatly among sites

Biogenic non-methane hydrocarbons (NMHC). Nature`s contribution to regional and global atmospheric chemistry

Energy Technology Data Exchange (ETDEWEB)

Klockow, D.; Hoffman, T. [Inst. of Spectrochemistry and Applied Spectroscopy, Dortmund (Germany)

1995-12-31

Terrestrial vegetation provides an important source of volatile hydrocarbons, especially isoprene, monoterpenes and in addition possibly sesquiterpenes as well as oxygenated compounds. Although there exist considerable uncertainties in the estimation of the magnitude of these biogenic NMHC emissions, it is generally accepted that the majority of global NMHC release is from natural and not from anthropogenic sources. Taking into consideration the high reactivity of the mostly unsaturated biogenic emissions, their impact on tropospheric processes can be assumed to be of great importance. Together with anthropogenic NO{sub x} emissions, the highly reactive natural alkenes can act as precursors in photochemical oxidant formation and contribute to regional-scale air pollution. Their oxidation in the atmosphere and the subsequent gas-to-particle conversion of the products lead to the formation of organic aerosols. Because of the formation of phytotoxic compounds, the interaction of the biogenic hydrocarbons with ozone inside or outside the leaves and needles of plants has been suggested to play a role in forest decline. (author)

Biogenic non-methane hydrocarbons (NMHC). Nature`s contribution to regional and global atmospheric chemistry

Energy Technology Data Exchange (ETDEWEB)

Klockow, D; Hoffman, T [Inst. of Spectrochemistry and Applied Spectroscopy, Dortmund (Germany)

1996-12-31

Terrestrial vegetation provides an important source of volatile hydrocarbons, especially isoprene, monoterpenes and in addition possibly sesquiterpenes as well as oxygenated compounds. Although there exist considerable uncertainties in the estimation of the magnitude of these biogenic NMHC emissions, it is generally accepted that the majority of global NMHC release is from natural and not from anthropogenic sources. Taking into consideration the high reactivity of the mostly unsaturated biogenic emissions, their impact on tropospheric processes can be assumed to be of great importance. Together with anthropogenic NO{sub x} emissions, the highly reactive natural alkenes can act as precursors in photochemical oxidant formation and contribute to regional-scale air pollution. Their oxidation in the atmosphere and the subsequent gas-to-particle conversion of the products lead to the formation of organic aerosols. Because of the formation of phytotoxic compounds, the interaction of the biogenic hydrocarbons with ozone inside or outside the leaves and needles of plants has been suggested to play a role in forest decline. (author)

Occurrence, source and ecological assessment of baseline hydrocarbons in the intertidal marine sediments along the shoreline of Douglas Channel to Hecate Strait in British Columbia.

Science.gov (United States)

Yang, Zeyu; Hollebone, Bruce P; Laforest, Sonia; Lambert, Patrick; Brown, Carl E; Yang, Chun; Shah, Keval; Landriault, Mike; Goldthorp, Michael

2017-09-15

The occurrence, source and ecological assessment of baseline hydrocarbons in the intertidal zone along the northern British shoreline were evaluated based on analyzing total petroleum hydrocarbons (TPH), n-alkanes, petroleum related biomarkers such as terpanes and steranes, and polycyclic aromatic hydrocarbons (PAHs) including non-alkylated and alkylated homologues (APAHs). The TPH levels, n-alkanes, petroleum biomarkers and PAHs in all the sampling sites, except for Masset Harbor/York Point at Gil Island were low, without obvious unresolved complex mixture (UCM) and petroleum contamination input. Specifically, n-alkanes showed a major terrestrial plants input; PAHs with abundant non-alkylated PAHs but minor APAHs showed a major pyrogenic input. However, obvious petroleum-derived hydrocarbons have impacted Masset Harbor. A historical petroleum input was found in York Point at Gil Island, due to the presence of the low level of petroleum biomarkers. Ecological assessment of 13 non-alkylated PAHs in Masset Harbor indicated no potential toxicity to the benthic organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial characterization of toluene-degrading denitrifying consortia obtained from terrestrial and marine ecosystems.

Science.gov (United States)

An, Y-J; Joo, Y-H; Hong, I-Y; Ryu, H-W; Cho, K-S

2004-10-01

The degradation characteristics of toluene coupled to nitrate reduction were investigated in enrichment culture and the microbial communities of toluene-degrading denitrifying consortia were characterized by denaturing gradient gel electrophoresis (DGGE) technique. Anaerobic nitrate-reducing bacteria were enriched from oil-contaminated soil samples collected from terrestrial (rice field) and marine (tidal flat) ecosystems. Enriched consortia degraded toluene in the presence of nitrate as a terminal electron acceptor. The degradation rate of toluene was affected by the initial substrate concentration and co-existence of other hydrocarbons. The types of toluene-degrading denitrifying consortia depended on the type of ecosystem. The clone RS-7 obtained from the enriched consortium of the rice field was most closely related to a toluene-degrading and denitrifying bacterium, Azoarcus denitrificians (A. tolulyticus sp. nov.). The clone TS-11 detected in the tidal flat enriched consortium was affiliated to Thauera sp. strain S2 (T. aminoaromatica sp. nov.) that was able to degrade toluene under denitrifying conditions. This indicates that environmental factors greatly influence microbial communities obtained from terrestrial (rice field) and marine (tidal flat) ecosystems.

A Permian methane seep system as a paleoenvironmental analogue for the pre-metazoan carbonate platforms

Directory of Open Access Journals (Sweden)

Lucas Veríssimo Warren

Full Text Available ABSTRACT: Following the rise of metazoans, the beginning of bioclasticity and substrate competition, the saga of microbial mats was in a fluctuating decline in the end of the Neoproterozoic era. Increases in diversity during the Phanerozoic and punctual upturns in the microbial carbonate production occured after the events of global mass extinctions. Gradually along the Phanerozoic, the microbial colonies occupied isolated niches and grazers-free environments, characterized by physically and/or geochemically stressful conditions, such as those found in saline bays, alkaline lakes and hydrothermal or cold seep vents. Here we report one of the oldest occurrences of a vent camp coupled with cold seepage of methane in the geologic record, associated with well-preserved microbialites and elephant skin structures. During the seep activity, oxygen depletion and high salinity conditions are prohibitive for complex animal life, clearing the way to microbial colonies to flourish. Due to the co-occurrence of high adaptability and low competitiveness of microbial forms, they became highly specialized in stressful conditions. We argue that the sporadic microbial mat upturns in Earth’s history are not restricted to geological periods, following massive death of metazoan species; they also may occur in response to punctual paleoenvironmental conditions that enable microbial colonies to growth. Indeed, the Phanerozoic geological record is punctuated of these examples, in a kind of hide-and-seek game of Precambrian times.

The aliphatic hydrocarbon distributions of terrestrial plants around an alpine lake: a pilot study from Lake Ximencuo, Eastern Qinghai-Tibet Plateau

Science.gov (United States)

Pu, Yang; Jia, Jihong; Cao, Jicheng

2017-12-01

As part of an investigation of the sources of aliphatic hydrocarbons to the sediments of alpine Lake Ximencuo, leaves of the eight dominant vascular plants were collected and their hydrocarbon contents were analyzed. A series of unsaturated aliphatic hydrocarbons were identified in the plant leaves; in particular, Festuca sp. contain a series of n-alkadienes that have rarely been reported in previous studies. The comparison of n-alkane proxies (ACL 27-33, ACL T, P aq, and CPI) and δ13Corg among plant leaves, surface soils, and lake sediments suggests that organic proxies have been altered to varying degrees during the transport and burial process of organic materials. It is believed that microbial reworking and source changes have great impacts on organic proxies in the alpine lake system. In addition, the cluster analysis for plant leaves depending on n-alkane compositions and the ACL T proxy generates similar results. Accordingly, we postulate that the average chain length of plant waxes might be a potential indicator of plant classification in regions such as the Qinghai-Tibet Plateau.

Seeping Deficit Thinking Assumptions Maintain the Neoliberal Education Agenda: Exploring Three Conceptual Frameworks of Deficit Thinking in Inner-City Schools

Science.gov (United States)

Sharma, Manu

2018-01-01

This article draws awareness to the subtle and seeping "common sense" mentality of neoliberalism and deficit thinking assumptions about racially marginalized students in inner-city schools. From a literature review conducted on deficit thinking and deficit practices in schools, I developed three different frameworks for understanding the…

A giant oil seep at a salt-induced escarpment of the São Paulo Plateau, Espírito Santo Basin, off Brazil: Host rock characteristics and geochemistry

Science.gov (United States)

Freire, Antonio Fernando Menezes; Iemini, Juliana Andrade; Viana, Adriano Roessler; Magnavita, Luciano Portugal; Dehler, Nolan Maia; Kowsmann, Renato Oscar; Miller, Dennis James; Bezerra, Sabrina Helena Diniz Gilaberte; Zerfass, Geise de Santana dos Anjos; Shimabukuro, Seirin; Nóbrega, Marcos, II

2017-12-01

An international research cruise named Iatá-Piuna took place on the São Paulo Plateau on May 2013 in the Campos and Espírito Santo basins, off Brazil. The cruise was carried ou on board the research vessel (R/V) Yokosuka that hosts the human operated vehicle (HOV) SHINKAI 6500. It aimed at finding chemosynthetic communities, composed of organisms capable of generating their own vital energy by metabolizing organic and inorganic compounds related to seeps. Identification of these organisms could provide information for understanding the origin of life, since they may resemble primitive organisms that existed in the initial stages of life on Earth. During Leg 2 (May 10-24, 2013), however, dives on the northern part of the São Paulo Plateau at the Espírito Santo Basin led to the discovery of a giant oil seep. The seep, ca. 3 nautical miles (ca. 5.6 km) in length is located along an outcrop of Eocene rocks on a salt-induced escarpment of the plateau and at a water depth of ca. 2700 m. The 200 m relief of the seafloor suggests that the seep takes place along an active fault system driven by salt diapirism. The oil was analyzed and identified as a severely biodegraded marine oil, generated by carbonate rocks within a minibasin located to the east of the escarpment. This represents valuable exploratory information because it proves that an active petroleum system is present in the context of minibasins associated with salt diapirism in the area.

Determination of levels of polycyclic aromatic hydrocarbons in soil ...

African Journals Online (AJOL)

MICHAEL HORSFALL

mishandling, deliberate disposal, spilling and leakage of petroleum products ... and eventually seeps into water bodies (Olugboji and ... solubility in water and are highly lipophilic. In water .... detect levels of PAHs in soils even at low levels and.

Occurrence and sources of aliphatic hydrocarbons in surface soils from Riyadh city, Saudi Arabia

Directory of Open Access Journals (Sweden)

Ahmed I. Rushdi

2013-01-01

Full Text Available Soil particles contain a variety of anthropogenic and natural organic components derived from many sources such as industrial and traffic fossil fuel emissions and terrestrial biota. The organic contents of soil and sand from the Arabian region have not fully characterized. Thus, samples of fine soil particles (sieved to <125 μM were collected from the Riyadh area in November 2006 (late summer and February 2007 (late winter. The samples were extracted with a mixture of dichloromethane/hexane and analyzed by gas chromatography–mass spectroscopy (GCMS in order to characterize the chemical composition and sources of aliphatic hydrocarbons. The results showed that both anthropogenic and natural biogenic inputs were the major sources of the aliphatic hydrocarbons in these extracts. Vehicular emission products and discarded plastics were the major anthropogenic sources in the fine particles of the soils and ranged from 64% to 96% in November 2006 and from 70% to 92% in February 2007. Their tracers were n-alkanes, hopanes, sterane, plasticizers and UCM. Vegetation was also a major natural source of hydrocarbon compounds in samples ranging from ∼0% to18% in November 2006 and from 1% to 13% in February 2007 and included n-alkanes and triterpenoids.

Characterization, Distribution, Sources and Origins of Aliphatic Hydrocarbons from Surface Sediment of Prai Strait, Penang, Malaysia: A Widespread Anthropogenic Input

Directory of Open Access Journals (Sweden)

Mahyar Sakari

2008-07-01

Full Text Available Persistent organic pollutants such as petroleum hydrocarbons are one of the most serious and important class of pollutants that face to many countries including Malaysia. Aliphatic hydrocarbons contain straight chain alkane; derive from anthropogenic and natural sources to the marine environment. The multi-purpose strait of Prai is located in the Northwest of Peninsular Malaysia plays an important economic role in the Southeast Asia. Twenty surface sediment samples were collected using Eckman dredge to measure the concentration and determine the characterization, sources and origins of the aliphatic hydrocarbons in December 2006. Samples (top 4 cm were extracted with Soxhlet, treated with activated copper and subjected to 2 steps column chromatography for purification and fractionation. Alkane fraction injected into Gas Chromatography–Flame Ionization Detector (GC-FID for instrumental analysis. The results showed that total n-alkane concentrations are ranging from 512 to 10770 ng/mg d. w. Carbon Preferences Index (CPI revealed an extreme widespread anthropogenic input and naturally derived (CPI= 0 to 4.88 hydrocarbons in the study area. The ratio of C31/C19 indicated that natural hydrocarbons are generating from terrestrial vascular plants and transferring by rivers. The characteristics of Major Hydrocarbons provided evidences that oil and its derivatives either fresh or degraded are the major contributors of the pollution in the study area. Statistical approaches also confirmed that 85% of study area affected by oil sources of pollution. It is seen that aliphatic hydrocarbons mostly transfer by lateral input to the marine environment than atmospheric movements.

Hydrocarbon Maturation and Os Mixing on Bolide Impact at the Frasnian-Famennian Boundary

Science.gov (United States)

Stein, H.; Zimmerman, A.; Yang, G.; Hannah, J.; Egenhoff, S.

2009-04-01

An intractable problem in the application of Re-Os geochemistry has been knowledge of the distribution of Re and Os between source rock and generated hydrocarbon. Solutions lie in combined experimental work with controlled and induced maturation, and field studies optimized by known source rock and time of hydrocarbon generation. The Siljan impact site with its variably tilted but largely intact Ordovician-Silurian sections provides an unsurpassed opportunity to examine the Re-Os systematics of source rock and generated crude oil, and the Re-Os imprint of the bolide. This three-component system contains (1) a time pin for maturation (377 ± 2 Ma; laser argon dating of impact melt, Reimold et al. 2005) arguably at the Frasnian-Famennian boundary, (2) known source rocks with kerogens still intact, and (3) crude oils generated on impact. Modeling takes into consideration the possibility of pre-impact maturation as well. At Siljan, numerous quarries expose the Upper Ordovician Boda and Kullsberg limestone mounds, and locally, the underlying and laterally equivalent Tretaspis (Fjäcka) shale. We obtained a sample of crude oil seeping from a drill hole in the quarry floor at Solberga. Preliminary Re-Os analyses on four aliquots of this oil form an excellent linear array in 187Re/188Os versus 187Os/188Os space. The associated age, however, is impossibly old (Neoproterozoic), and the initial 187Os/188Os unreasonably low (0.2). Rather, this linear array fits a mixing line between a meteoritic component and a hydrocarbon generated from the Tretaspis shale. We are presently performing further tests to isolate the two end-members. Filtering suggests that the extraterrestrial component consists of small physical particles which can be largely removed from the petroleum fraction. The extreme contrast in Re-Os composition between meteorite (known) and black shale (in progress) end-members maximizes the sensitivity of the isotopic study. Reimold, W.U., Kelley, S.P., Sherlock, S

Microsensor studies on Padina from a natural CO2 seep: implications of morphology on acclimation to low pH.

Science.gov (United States)

Hofmann, Laurie C; Fink, Artur; Bischof, Kai; de Beer, Dirk

2015-12-01

Low seawater pH can be harmful to many calcifying marine organisms, but the calcifying macroalgae Padina spp. flourish at natural submarine carbon dioxide seeps where seawater pH is low. We show that the microenvironment created by the rolled thallus margin of Padina australis facilitates supersaturation of CaCO3 and calcifi-cation via photosynthesis-induced elevated pH. Using microsensors to investigate oxygen and pH dynamics in the microenvironment of P. australis at a shallow CO2 seep, we found that, under saturating light, the pH inside the microenvironment (pHME ) was higher than the external seawater (pHSW ) at all pHSW levels investigated, and the difference (i.e., pHME - pHSW ) increased with decreasing pHSW (0.9 units at pHSW 7.0). Gross photosynthesis (Pg ) inside the microenvironment increased with decreasing pHSW , but algae from the control site reached a threshold at pH 6.5. Seep algae showed no pH threshold with respect to Pg within the pHSW range investigated. The external carbonic anhydrase (CA) inhibitor, acetazolamide, strongly inhibited Pg of P. australis at pHSW 8.2, but the effect was diminished under low pHSW (6.4-7.5), suggesting a greater dependence on membrane-bound CA for the dehydration of HCO3 (-) ions during dissolved inorganic carbon uptake at the higher pHSW . In comparison, a calcifying green alga, Halimeda cuneata f. digitata, was not inhibited by AZ, suggesting efficient bicarbonate transport. The ability of P. australis to elevate pHME at the site of calcification and its strong dependence on CA may explain why it can thrive at low pHSW . © 2015 Phycological Society of America.

Distribution of hydrocarbon-utilizing microorganisms and hydrocarbon biodegradation potentials in Alaskan continental shelf areas

International Nuclear Information System (INIS)

Roubal, G.; Atlas, R.M.

1978-01-01

Hydrocarbon-utilizing microogranisms were enumerated from Alaskan continental shelf areas by using plate counts and a new most-probable-number procedure based on mineralization of 14 C-labeled hydrocarbons. Hydrocarbon utilizers were ubiquitously distributed, with no significant overall concentration differences between sampling regions or between surface water and sediment samples. There were, however, significant seasonal differences in numbers of hydrocarbon utilizers. Distribution of hydrocarbon utilizers within Cook Inlet was positively correlated with occurrence of hydrocarbons in the environment. Hydrocarbon biodegradation potentials were measured by using 14 C-radiolabeled hydrocarbon-spiked crude oil. There was no significant correlation between numbers of hydrocarbon utilizers and hydrocarbon biodegradation potentials. The biodegradation potentials showed large seasonal variations in the Beaufort Sea, probably due to seasonal depletion of available nutrients. Non-nutrient-limited biodegradation potentials followed the order hexadecane > naphthalene >> pristane > benzanthracene. In Cook Inlet, biodegradation potentials for hexadecane and naphthalene were dependent on availability of inorganic nutrients. Biodegradation potentials for pristane and benzanthracene were restricted, probably by resistance to attack by available enzymes in the indigenous population

Origin and distribution of hydrocarbons and organic matter in the surficial sediments of the Sfax-Kerkennah channel (Tunisia, Southern Mediterranean Sea)

International Nuclear Information System (INIS)

Zaghden, Hatem; Tedetti, Marc; Sayadi, Sami; Serbaji, Mohamed Moncef; Elleuch, Boubaker; Saliot, Alain

2017-01-01

We investigated the origin and distribution of aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs) and organic matter (OM) in surficial sediments of the Sfax-Kerkennah channel in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea). TOC, AH and PAH concentrations ranged 2.3–11.7%, 8–174 μg g −1 sed. dw and 175–10,769 ng g −1 sed. dw, respectively. The lowest concentrations were recorded in the channel (medium sand sediment) and the highest ones in the Sfax harbor (very fine sand sediment). AHs, PAHs and TOC were not correlated for most of the stations. TOC/N and δ 13 C values revealed a mixed origin of OM with both marine and terrestrial sources. Hydrocarbon molecular composition highlighted the dominance of petrogenic AHs and the presence of both petrogenic and pyrogenic PAHs, associated with petroleum products and combustion processes. This work underscores the complex distribution patterns and the multiple sources of OM and hydrocarbons in this highly anthropogenized coastal environment. - Highlights: • TOC, AHs and PAHs ranged 2–12%, 8–174 μg g −1 sed. dw and 175–10,769 ng g −1 sed. dw. • Lowest concentrations in the Sfax-Kerkennah channel, highest ones in the Sfax harbor • Decoupling between TOC, AH and PAH contents • TOC/N and δ 13 C values revealed a mixed origin of OM with marine and terrestrial sources. • Dominance of petrogenic AHs and presence of both petrogenic and pyrogenic PAHs

Plasma devices for hydrocarbon reformation

KAUST Repository

Cha, Min Suk

2017-02-16

Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured to be submerged in the liquid. The plasma plume from the plasma torch can cause reformation of the hydrocarbon. The device can use a variety of plasma torches that can be arranged in a variety of positions in the liquid container. The devices can be used for the reformation of gaseous hydrocarbons and/or liquid hydrocarbons. The reformation can produce methane, lower hydrocarbons, higher hydrocarbons, hydrogen gas, water, carbon dioxide, carbon monoxide, or a combination thereof.

Petroleum hydrocarbons

International Nuclear Information System (INIS)

Farrington, J.W.; Teal, J.M.; Parker, P.L.

1976-01-01

Methods for analysis of petroleum hydrocarbons in marine samples are presented. Types of hydrocarbons present and their origins are discussed. Principles and methods of analysis are outlined. Infrared spectrometry, uv spectrometry, gas chromatography, mass spectroscopy, and carbon 14 measurements are described

Seeps and springs sampling and analysis plant for the Environmental Monitoring Plan at Waste Area Grouping 6, Oak Ridge National Laboratory, Oak Ridge, Tennessee

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-09-01

This Sampling and Analysis Plan addresses the monitoring, sampling, and analysis activities that will be conducted at seeps and springs and at two french drain outlets in support of the Environmental Monitoring Plan for Waste Area Grouping (WAG) 6. WAG 6 is a shallow-land-burial disposal facility for low-level radioactive waste at Oak Ridge National Laboratory, a research facility owned by the U.S. Department of Energy and operated by Lockheed Martin Energy System, Inc. Initially, sampling will be conducted at as many as 15 locations within WAG 6 (as many as 13 seeps and 2 french drain outlets). After evaluating the results obtained and reviewing the observations made by field personnel during the first round of sampling, several seeps and springs will be chosen as permanent monitoring points, together with the two french drain outlets. Baseline sampling of these points will then be conducted quarterly for 1 year (i.e., four rounds of sampling after the initial round). The samples will be analyzed for various geochemical, organic, inorganic, and radiological parameters. Permanent sampling points having suitable flow rates and conditions may be outfitted with automatic flow-monitoring equipment. The results of the sampling and flow-monitoring efforts will help to quantify flux moving across the ungauged perimeter of the site and will help to identify changes in releases from the contaminant sources.

Seeps and springs sampling and analysis plant for the Environmental Monitoring Plan at Waste Area Grouping 6, Oak Ridge National Laboratory, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1995-09-01

This Sampling and Analysis Plan addresses the monitoring, sampling, and analysis activities that will be conducted at seeps and springs and at two french drain outlets in support of the Environmental Monitoring Plan for Waste Area Grouping (WAG) 6. WAG 6 is a shallow-land-burial disposal facility for low-level radioactive waste at Oak Ridge National Laboratory, a research facility owned by the U.S. Department of Energy and operated by Lockheed Martin Energy System, Inc. Initially, sampling will be conducted at as many as 15 locations within WAG 6 (as many as 13 seeps and 2 french drain outlets). After evaluating the results obtained and reviewing the observations made by field personnel during the first round of sampling, several seeps and springs will be chosen as permanent monitoring points, together with the two french drain outlets. Baseline sampling of these points will then be conducted quarterly for 1 year (i.e., four rounds of sampling after the initial round). The samples will be analyzed for various geochemical, organic, inorganic, and radiological parameters. Permanent sampling points having suitable flow rates and conditions may be outfitted with automatic flow-monitoring equipment. The results of the sampling and flow-monitoring efforts will help to quantify flux moving across the ungauged perimeter of the site and will help to identify changes in releases from the contaminant sources

Two-Dimensional Heat Transfer Modeling of the Formosa Ridge Offshore SW Taiwan: Implication for Fluid Migrating Paths of a Cold Seep Site

Science.gov (United States)

Tsai, Y.; Chi, W.; Liu, C.; Shyu, C.

2011-12-01

The Formosa Ridge, a small ridge located on the passive China continental slope offshore southwestern Taiwan, is an active cold seep site. Large and dense chemosynthetic communities were found there by the ROV Hyper-Dolphin during the 2007 NT0705 cruise. A vertical blank zone is clearly observed on all the seismic profiles across the cold seep site. This narrow zone is interpreted to be the fluid conduit of the seep site. Previous studies suggest that cold sea water carrying large amount of sulfate could flow into the fluid system from flanks of the ridge, and forms a very effective fluid circulation system that emits both methane and hydrogen sulfide to feed the unusual chemosynthetic communities observed at the Formosa Ridge cold seep site. Here we use thermal signals to study possible fluid flow migration paths. In 2008 and 2010, we have collected vdense thermal probe data at this site. We also study the temperatures at Bottom-Simulating Reflectors (BSRs) based on methane hydrate phase diagram. We perform 2D finite element thermal conductive simulations to study the effects of bathymetry on the temperature field in the ridge, and compare the simulation result with thermal probe and BSR-derived datasets. The boundary conditions include insulated boundaries on both sides, and we assign a fix temperature at the bottom of the model using an average regional geothermal gradient. Sensitivity tests and thermal probe data from a nearby region give a regional background geothermal gradient of 0.04 to 0.05 °C/m. The outputs of the simulation runs include geothermal gradient and temperature at different parts of the model. The model can fit the geothermal gradient at a distance away from the ridge where there is less geophysics evidence of fluid flow. However our model over-predicts the geothermal gradient by 50% at the ridge top. We also compare simulated temperature field and found that under the flanks of the ridge the temperature is cooled by 2 °C compared with the

Converting high boiling hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Terrisse, H; DuFour, L

1929-02-12

A process is given for converting high boiling hydrocarbons into low boiling hydrocarbons, characterized in that the high boiling hydrocarbons are heated to 200 to 500/sup 0/C in the presence of ferrous chloride and of such gases as hydrogen, water gas, and the like gases under a pressure of from 5 to 40 kilograms per square centimeter. The desulfurization of the hydrocarbons occurs simultaneously.

Identification of interstellar polysaccharides and related hydrocarbons

International Nuclear Information System (INIS)

Hoyle, F.; Olavesen, A.H.; Wickramasinghe, N.C.

1978-01-01

A discussion is presented on the infrared transmittance spectra of several polysaccharides that may be of interest as possible interstellar candidates. It is stated that a 2.5 to 15 μm spectrum computed from the author's measurements is remarkably close to that required to explain a wide range of astronomical data, except for two points. First the required relative opacity at the 3 μm absorption dip is a factor of about 1.5 lower than was found in laboratory measurements; this difference may arise from the presence of water in terrestrial polysaccharide samples. Secondly, in the 9.5 to 12 μm waveband an additional source of opacity appears to be necessary. Close agreement between the spectrum of this additional opacity and the absorption spectrum of propene, C 3 H 6 , points strongly to the presence of hydrocarbons of this type, which may be associated with polysaccharide grains in interstellar space. (U.K.)

E/V Nautilus Detection of Isolated Features in the Eastern Pacific Ocean: Newly Discovered Calderas and Methane Seeps

Science.gov (United States)

Raineault, N.; Irish, O.; Lubetkin, M.

2016-02-01

The E/V Nautilus mapped over 80,000 km2 of the seafloor in the Gulf of Mexico and Eastern Pacific Ocean during its 2015 expedition. The Nautilus used its Kongsberg EM302 multibeam system to map the seafloor prior to remotely operated vehicle (ROV) dives, both for scientific purposes (site selection) and navigational safety. The Nautilus also routinely maps during transits to identify previously un-mapped or unresolved seafloor features. During its transit from the Galapagos Islands to the California Borderland, the Nautilus mapped 44,695 km2 of seafloor. Isolated features on the seafloor and in the water-column, such as calderas and methane seeps, were detected during this data collection effort. Operating at a frequency of 30 kHz in waters ranging from 1000-5500 m, we discovered caldera features off the coast of Central America. Since seamounts are known hotspots of biodiversity, locating new ones may enrich our understanding of seamounts as "stepping stones" for species distribution and ocean current pathways. Satellite altimetry datasets prior to this data either did not discern these calderas or recognized the presence of a bathymetric high without great detail. This new multibeam bathymetry data, gridded at 50 m, gives a precise look at these seamounts that range in elevation from 350 to 1400 m from abyssal depth. The largest of the calderas is circular in shape and is 10,000 m in length and 5,000 m in width, with a distinct circular depression at the center of its highest point, 1,400 m above the surrounding abyssal depth. In the California Borderland region, located between San Diego and Los Angeles, four new seeps were discovered in water depths from 400-1,020 m. ROV exploration of these seeps revealed vent communities. Altogether, these discoveries reinforce how little we know about the global ocean, indicate the presence of isolated deep-sea ecosystems that support biologically diverse communities, and will impact our understanding of seafloor habitat.

Production of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Day, D T; Day, R E

1920-04-27

A process is disclosed of converting hydro-carbon oils having high boiling points to hydro-carbon oils having low boiling points, which process comprises adding the oil to be treated to a mass of hydro-carbon oil bearing shale, passing the shale with the oil through a conveyor retort and subjecting the material while in the retort to a heat treatment involving a temperature of at least 500/sup 0/F.

Seeps and springs sampling and analysis plan for the environmental monitoring plan for Waste Area Grouping 6 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

Energy Technology Data Exchange (ETDEWEB)

1994-08-01

This Sampling and Analysis Plan addresses the monitoring, sampling, and analysis activities that will be conducted at seeps and springs and at two french drain outlets in support of the Environmental Monitoring Plan for Waste Area Grouping (WAG) 6. WAG 6 is a shallow-land-burial disposal facility for low-level radioactive waste at Oak Ridge National Laboratory, a research facility owned by the US Department of Energy and operated by Martin Marietta Energy Systems, Inc. Initially, sampling will be conducted at as many as 15 locations within WAG 6 (as many as 13 seeps and 2 french drain outlets). After evaluating the results obtained and reviewing the observations made by field personnel during the first round of sampling, several seeps and springs will be chosen as permanent monitoring points, together with the two french drain outlets. Baseline sampling of these points will then be conducted quarterly for 1 year (i.e., four rounds of sampling after the initial round). The samples will be analyzed for various geochemical, organic, inorganic, and radiological parameters. Permanent sampling points having suitable flow rates and conditions may be outfitted with automatic flow-monitoring equipment. The results of the sampling and flow-monitoring efforts will help to quantify flux moving across the ungauged perimeter of the site and will help to identify changes in releases from the contaminant sources.

Seeps and springs sampling and analysis plan for the environmental monitoring plan for Waste Area Grouping 6 at Oak Ridge National Laboratory, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1994-08-01

This Sampling and Analysis Plan addresses the monitoring, sampling, and analysis activities that will be conducted at seeps and springs and at two french drain outlets in support of the Environmental Monitoring Plan for Waste Area Grouping (WAG) 6. WAG 6 is a shallow-land-burial disposal facility for low-level radioactive waste at Oak Ridge National Laboratory, a research facility owned by the US Department of Energy and operated by Martin Marietta Energy Systems, Inc. Initially, sampling will be conducted at as many as 15 locations within WAG 6 (as many as 13 seeps and 2 french drain outlets). After evaluating the results obtained and reviewing the observations made by field personnel during the first round of sampling, several seeps and springs will be chosen as permanent monitoring points, together with the two french drain outlets. Baseline sampling of these points will then be conducted quarterly for 1 year (i.e., four rounds of sampling after the initial round). The samples will be analyzed for various geochemical, organic, inorganic, and radiological parameters. Permanent sampling points having suitable flow rates and conditions may be outfitted with automatic flow-monitoring equipment. The results of the sampling and flow-monitoring efforts will help to quantify flux moving across the ungauged perimeter of the site and will help to identify changes in releases from the contaminant sources

Lower Carboniferous Siderites: A Product of Bottom Seeps and Bacterial Metanogenesis (Subpolar Urals)

Science.gov (United States)

Antoshkina, A. I.; Ryabinkina, N. N.

2018-02-01

Complex modern micro- and spectroscopic methods for study of siderite concretions in the Lower Carboniferous terrigenous strata on the Kozhym River (Subpolar Urals) have shown that its formation was caused by destruction of clay minerals due to the activity of bacterial communities. The abundance of these bacteria was caused by gas-fluid seeps and bacterial methanogenesis processes in bottom deposits. In basins with normal marine fauna, this led to local desalination, hydrogen sulfide contamination, mass collapse of primary organisms, and the development of element-specific bacteria. The occurrence of these bacteria caused the formation of specific authigenic mineralization in the concretion of sideritic bacteriolites: the framboidal pyrite, sphalerite, galenite, barite, sulfoselenides, and tellurides.

Contaminant exposure in terrestrial vertebrates

International Nuclear Information System (INIS)

Smith, Philip N.; Cobb, George P.; Godard-Codding, Celine; Hoff, Dale; McMurry, Scott T.; Rainwater, Thomas R.; Reynolds, Kevin D.

2007-01-01

Here we review mechanisms and factors influencing contaminant exposure among terrestrial vertebrate wildlife. There exists a complex mixture of biotic and abiotic factors that dictate potential for contaminant exposure among terrestrial and semi-terrestrial vertebrates. Chemical fate and transport in the environment determine contaminant bioaccessibility. Species-specific natural history characteristics and behavioral traits then play significant roles in the likelihood that exposure pathways, from source to receptor, are complete. Detailed knowledge of natural history traits of receptors considered in conjunction with the knowledge of contaminant behavior and distribution on a site are critical when assessing and quantifying exposure. We review limitations in our understanding of elements of exposure and the unique aspects of exposure associated with terrestrial and semi-terrestrial taxa. We provide insight on taxa-specific traits that contribute, or limit exposure to, transport phenomenon that influence exposure throughout terrestrial systems, novel contaminants, bioavailability, exposure data analysis, and uncertainty associated with exposure in wildlife risk assessments. Lastly, we identify areas related to exposure among terrestrial and semi-terrestrial organisms that warrant additional research. - Both biotic and abiotic factors determine chemical exposure for terrestrial vertebrates

Can hydrocarbons in coastal sediments be related to terrestrial flux? A case study of Godavari river discharge (Bay of Bengal)

Digital Repository Service at National Institute of Oceanography (India)

Rayaprolu, K.; GopalaKrishna, V.V.J.; Naik, B.G.; Mahalakshmi, G.; Rengarajan, R.; Mazumdar, A; Sarma, N.S.

A sediment core aged ~250 years and deposition rate of ~2.4 mm yr^-1 raised from the coastal region receiving inputs from the Godavari river was examined for n-alkanes The carbon preference index (CPI) of shortchain hydrocarbons (SHC...

Performance of a Throttle Cycle Refrigerator with Nitrogen-Hydrocarbon and Argon-Hydrocarbon Mixtures

Science.gov (United States)

Venkatarathnam, G.; Senthil Kumar, P.; Srinivasa Murthy, S.

2004-06-01

Throttle cycle refrigerators are a class of vapor compression refrigerators that can provide refrigeration at cryogenic temperatures and operate with refrigerant mixtures. The performance of our prototype refrigerators with nitrogen-hydrocarbon, nitrogen-hydrocarbon-helium and argon-hydrocarbon refrigerant mixtures is presented in this paper.

Petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) in Hong Kong marine sediments

International Nuclear Information System (INIS)

Zheng, G.J.; Richardson, B.J.

1999-01-01

A total of 20 surficial sediment samples, obtained from Hong Kong coastal waters, were analysed for petroleum hydrocarbons (PHCs) and a suite of 15 polycyclic aromatic hydrocarbons (PAHs). The results indicate that Hong Kong coastal sediments are often seriously polluted with petroleum related hydrocarbons. This is especially so in heavily urbanised or industrialized localities, such as Kowloon Bay (Victoria Harbour), Tsing Yi North and Tolo Harbour. Petroleum hydrocarbon pollutants in marine sediments are believed to be mainly derived from the transportation of oil, shipping activities, spillages, and industrial, stormwater and waste wastewater discharge. The ratio of unresolved complex mixture (UCM) to n-alkanes, carbon preference index (CPI), and n-C 16 values indicate that the main contribution to petroleum hydrocarbon contamination is via oil and its products. Pollutant sources appear to be stable and continuing when compared with previous data. (author)

Purifying hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Demoulins, H D; Garner, F H

1923-02-07

Hydrocarbon distillates, including natural gases and vapors produced by cracking hydrocarbon oils, are desulfurized etc. by treating the vapor with an aqueous alkaline solution of an oxidizing agent. The hydrocarbons may be previously purified by sulfuric acid. In examples aqueous solutions of sodium or calcium hydrochlorite containing 1.5 to 5.0 grams per liter of available chlorine and sufficient alkali to give an excess of 0.1 percent in the spent reagent are preheated to the temperature of the vapor, and either sprayed or atomized into the vapors near the outlet of the dephlegmator or fractionating tower, or passed in countercurrent to the vapors through one or a series of scrubbers.

Origin and distribution of hydrocarbons and organic matter in the surficial sediments of the Sfax-Kerkennah channel (Tunisia, Southern Mediterranean Sea).

Science.gov (United States)

Zaghden, Hatem; Tedetti, Marc; Sayadi, Sami; Serbaji, Mohamed Moncef; Elleuch, Boubaker; Saliot, Alain

2017-04-15

We investigated the origin and distribution of aliphatic and polycyclic aromatic hydrocarbons (AHs and PAHs) and organic matter (OM) in surficial sediments of the Sfax-Kerkennah channel in the Gulf of Gabès (Tunisia, Southern Mediterranean Sea). TOC, AH and PAH concentrations ranged 2.3-11.7%, 8-174μgg -1 sed.dw and 175-10,769ngg -1 sed.dw, respectively. The lowest concentrations were recorded in the channel (medium sand sediment) and the highest ones in the Sfax harbor (very fine sand sediment). AHs, PAHs and TOC were not correlated for most of the stations. TOC/N and δ 13 C values revealed a mixed origin of OM with both marine and terrestrial sources. Hydrocarbon molecular composition highlighted the dominance of petrogenic AHs and the presence of both petrogenic and pyrogenic PAHs, associated with petroleum products and combustion processes. This work underscores the complex distribution patterns and the multiple sources of OM and hydrocarbons in this highly anthropogenized coastal environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental switching during biofilm development in a cold seep system and functional determinants of species sorting

KAUST Repository

Zhang, Weipeng; Tian, Renmao; Yang, Bo; Cao, Huiluo; Cai, Lin; Chen, Lianguo; Zhou, Guowei; Sun, Jingya; Zhang, Xixiang; Al-Suwailem, Abdulaziz M.; Qian, Pei-Yuan

2015-01-01

The functional basis for species sorting theory remains elusive, especially for microbial community assembly in deep sea environments. Using artificial surface-based biofilm models, our recent work revealed taxonomic succession during biofilm development in a newly defined cold seep system, the Thuwal cold seeps II, which comprises a brine pool and the adjacent normal bottom water (NBW) to form a metacommunity via the potential immigration of organisms from one patch to another. Here, we designed an experiment to investigate the effects of environmental switching between the brine pool and the NBW on biofilm assembly, which could reflect environmental filtering effects during bacterial immigration to new environments. Analyses of 16S rRNA genes of 71 biofilm samples suggested that the microbial composition of biofilms established in new environments was determined by both the source community and the incubation conditions. Moreover, a comparison of 18 metagenomes provided evidence for biofilm community assembly that was based primarily on functional features rather than taxonomic identities; metal ion resistance and amino acid metabolism were the major species sorting determinants for the succession of biofilm communities. Genome binning and pathway reconstruction of two bacterial species (Marinobacter sp. and Oleispira sp.) further demonstrated metal ion resistance and amino acid metabolism as functional traits conferring the survival of habitat generalists in both the brine pool and NBW. The results of the present study sheds new light on microbial community assembly in special habitats and bridges a gap in species sorting theory.

Environmental switching during biofilm development in a cold seep system and functional determinants of species sorting

KAUST Repository

Zhang, Weipeng

2015-11-28

The functional basis for species sorting theory remains elusive, especially for microbial community assembly in deep sea environments. Using artificial surface-based biofilm models, our recent work revealed taxonomic succession during biofilm development in a newly defined cold seep system, the Thuwal cold seeps II, which comprises a brine pool and the adjacent normal bottom water (NBW) to form a metacommunity via the potential immigration of organisms from one patch to another. Here, we designed an experiment to investigate the effects of environmental switching between the brine pool and the NBW on biofilm assembly, which could reflect environmental filtering effects during bacterial immigration to new environments. Analyses of 16S rRNA genes of 71 biofilm samples suggested that the microbial composition of biofilms established in new environments was determined by both the source community and the incubation conditions. Moreover, a comparison of 18 metagenomes provided evidence for biofilm community assembly that was based primarily on functional features rather than taxonomic identities; metal ion resistance and amino acid metabolism were the major species sorting determinants for the succession of biofilm communities. Genome binning and pathway reconstruction of two bacterial species (Marinobacter sp. and Oleispira sp.) further demonstrated metal ion resistance and amino acid metabolism as functional traits conferring the survival of habitat generalists in both the brine pool and NBW. The results of the present study sheds new light on microbial community assembly in special habitats and bridges a gap in species sorting theory.

Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography

NARCIS (Netherlands)

Plum, C.; Gollner, S.; Martinez Arbizu, P.; Bright, M.

2015-01-01

In order to characterize the copepod communitiesassociated with tubeworm and mussel aggregations around ahydrocarbon seep in the Green Canyon of the Gulf of Mexico,diversity, abundance, and community composition were analyzed.Also analyzed were species biogeography and the potentialconnectivity to

Synergy in Sulfur Cycle: The Biogeochemical Significance of Sulfate Reducing Bacteria in Syntrophic Associations

Digital Repository Service at National Institute of Oceanography (India)

LokaBharathi, P.A.

. Consideration of the oasis analogy for chemosyntheticcommunities at Gulf of Mexico hydrocarbon vents. Geo. Mar. Lett. 14,149-159 Douglas, A.E.,2004. Strategies in antagonistic and cooperative interactions. Microbial Evolution. Gene Establishment, survival... and fuels. Plenum, New York, pp 277?296. MacAvoy, S.A., Macko, S.A., Joye, S.B., 2002. Fatty acid carbon isotope signatures in chemosynthetic mussels and tube worms from Gulf of Mexico hydrocarbon seep communities. Chem.Geol. 185, 1 ? 8. Michaelis, W...

Arctic Terrestrial Biodiversity Monitoring Plan

DEFF Research Database (Denmark)

Christensen, Tom; Payne, J.; Doyle, M.

The Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council, established the Circumpolar Biodiversity Monitoring Program (CBMP) to address the need for coordinated and standardized monitoring of Arctic environments. The CBMP includes an international...... on developing and implementing long-term plans for monitoring the integrity of Arctic biomes: terrestrial, marine, freshwater, and coastal (under development) environments. The CBMP Terrestrial Expert Monitoring Group (CBMP-TEMG) has developed the Arctic Terrestrial Biodiversity Monitoring Plan (CBMP......-Terrestrial Plan/the Plan) as the framework for coordinated, long-term Arctic terrestrial biodiversity monitoring. The goal of the CBMP-Terrestrial Plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect, understand and report on long...

The oceanic geochemistry of artificial radionuclides: The ''SEEP'' project: [Final] progress report for period 1 August 1986-31 July 1987

International Nuclear Information System (INIS)

Sholkovitz, E.R.; Livingston, H.D.

1986-03-01

The objective of the SEEP project was to quantify the biological and geochemical processes controlling the concentration, distribution, flux, and speciation of natural and artificial radionuclides. The focus is on the shelf/slope region. Research was concentrated on the sediment chemistry of plutonium and on the nature of fallout transuranic transport in, and removal from, waters of the US continental margin

Microplastics in the terrestrial ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae)

NARCIS (Netherlands)

Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.D.; Salanki, T.E.; Ploeg, van der M.J.C.; Besseling, E.; Koelmans, A.A.; Geissen, V.

2016-01-01

Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, <150 μm)

Dissolved Organic Carbon and Natural Terrestrial Sequestration Potential in Volcanic Terrain, San Juan Mountains, Colorado

Science.gov (United States)

Yager, D. B.; Burchell, A.; Johnson, R. H.; Kugel, M.; Aiken, G.; Dick, R.

2009-12-01

The need to reduce atmospheric CO2 levels has stimulated studies to understand and quantify carbon sinks and sources. Soils represent a potentially significant natural terrestrial carbon sequestration (NTS) reservoir. This project is part of a collaborative effort to characterize carbon (C) stability in temperate soils. To examine the potential for dissolved organic carbon (DOC) values as a qualitative indicator of C-stability, peak-flow (1500 ft3/s) and low-flow (200 ft3/s) samples from surface and ground waters were measured for DOC. DOC concentrations are generally low. Median peak-flow values from all sample sites (mg/L) were: streams (0.9); seeps (1.2); wells (0.45). Median low-flow values were: streams (0.7); seeps (0.75); wells (0.5). Median DOC values decrease between June and September 0.45 mg/L for seeps, and 0.2 mg/L for streams. Elevated DOC in some ground waters as compared to surface waters indicates increased contact time with soil organic matter. Elevated peak-flow DOC in areas with propylitically-altered bedrocks, composed of a secondary acid neutralizing assemblage of calcite-chlorite-epidote, reflects increased microbial and vegetation activity as compared to reduced organic matter accumulation in highly-altered terrain composed of an acid generating assemblage with abundant pyrite. Waters sampled in propylitically-altered bedrock terrain exhibit the lowest values during low-flow and suggest bedrock alteration type may influence DOC. Previous studies revealed undisturbed soils sampled have 2 to 6 times greater total organic soil carbon (TOSC) than global averages. Forest soils underlain by intermediate to mafic volcanic bedrock have the highest C (34.15 wt%), C: N (43) and arylsulfatase enzyme activity (ave. 278, high 461 µg p-nitrophenol/g/h). Unreclaimed mine sites have the lowest C (0 to 0.78 wt%), and arylsulfatase enzyme activity (0 to 41). Radiocarbon dates on charcoal collected from paleo-burn horizons illustrate Rocky Mountain soils may

Adaptation to the deep-sea hydrothermal vents and cold seeps: Insights from the transcriptomes of Alvinocaris longirostris in both environments

Science.gov (United States)

Hui, Min; Cheng, Jiao; Sha, Zhongli

2018-05-01

Alvinocaris longirostris Kikuchi and Ohta, 1995 is one of the few species co-distributed in deep-sea hydrothermal vent and cold seep environments. We performed the transcriptome analysis for A. longirostris and identified differentially expressed genes (DEGs) between samples from the Iheya North hydrothermal vent (HV) and a methane seep in the South China Sea (MS). From the 57,801 annotated unigenes, multi-copies of enzyme family members for eliminating toxic xenobiotics were isolated and seven putatively duplicated gene clusters of cytochrome P450s were discovered, which may contribute to adaptation to the harsh conditions. Eight single amino acid substitutions of a Rhodopsin gene with low expression in two deep-sea alvinocaridid species were positively selected when compared with shallow water shrimps, which may be the result of adaptation to the dim-light environment in deep sea. 408 DEGs were identified with 53 and 355 up-regulated in HV and MS, respectively. Various genes associated with sulfur metabolism, detoxification and mitochondria were included, revealing different mechanisms of adaptation to the two types of extreme environments. All results are expected to serve as important basis for the further study.

Plasma devices for hydrocarbon reformation

KAUST Repository

Cha, Min

2017-01-01

Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured

Microplastics in the Terrestrial Ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae).

Science.gov (United States)

Huerta Lwanga, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A; Geissen, Violette

2016-03-01

Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, digestion of ingested organic matter, microplastic was concentrated in cast, especially at the lowest dose (i.e., 7% in litter) because that dose had the highest proportion of digestible organic matter. Whereas 50 percent of the microplastics had a size of earthworms. These concentration-transport and size-selection mechanisms may have important implications for fate and risk of microplastic in terrestrial ecosystems.

Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane.

Science.gov (United States)

Pohlman, John W; Greinert, Jens; Ruppel, Carolyn; Silyakova, Anna; Vielstädte, Lisa; Casso, Michael; Mienert, Jürgen; Bünz, Stefan

2017-05-23

Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 10 6 tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (shallow ebullitive methane seep field on the Svalbard margin reveal atmospheric CO 2 uptake rates (-33,300 ± 7,900 μmol m -2 ⋅d -1 ) twice that of surrounding waters and ∼1,900 times greater than the diffusive sea-air methane efflux (17.3 ± 4.8 μmol m -2 ⋅d -1 ). The negative radiative forcing expected from this CO 2 uptake is up to 231 times greater than the positive radiative forcing from the methane emissions. Surface water characteristics (e.g., high dissolved oxygen, high pH, and enrichment of 13 C in CO 2 ) indicate that upwelling of cold, nutrient-rich water from near the seafloor accompanies methane emissions and stimulates CO 2 consumption by photosynthesizing phytoplankton. These findings challenge the widely held perception that areas characterized by shallow-water methane seeps and/or strongly elevated sea-air methane flux always increase the global atmospheric greenhouse gas burden.

Dynamics of cell proliferation and apoptosis reflect different life strategies in hydrothermal vent and cold seep vestimentiferan tubeworms.

Science.gov (United States)

Pflugfelder, Bettina; Cary, S Craig; Bright, Monika

2009-07-01

Deep-sea vestimentiferan tubeworms, which live in symbiosis with bacteria, exhibit different life strategies according to their habitat. At unstable and relatively short-lived hydrothermal vents, they grow extremely fast, whereas their close relatives at stable and long-persisting cold seeps grow slowly and live up to 300 years. Growth and age differences are thought to occur because of ecological and physiological adaptations. However, the underlying mechanisms of cell proliferation and death, which are closely linked to homeostasis, growth, and longevity, are unknown. Here, we show by immunohistochemical and ultrastructural cell cycle analyses that cell proliferation activities of the two species studied are higher than in any other characterized invertebrate, being only comparable with tumor and wound-healing processes. The slow growth in Lamellibrachia luymesi from cold seeps results from balanced activities of proliferation and apoptosis in the epidermis. In contrast, Riftia pachyptila from hydrothermal vents grows fast because apoptosis is down-regulated in this tissue. The symbiont-housing organ, the trophosome, exhibits a complex cell cycle and terminal differentiation pattern in both species, and growth is regulated by proliferation. These mechanisms have similarities to the up- and down-regulation of proliferation or apoptosis in various types of tumor, although they occur in healthy animals in this study, thus providing significant insights into the underlying mechanisms of growth and longevity.

Environmental switching during biofilm development in a cold seep system and functional determinants of species sorting.

Science.gov (United States)

Zhang, Weipeng; Tian, Renmao; Bo, Yang; Cao, Huiluo; Cai, Lin; Chen, Lianguo; Zhou, Guowei; Sun, Jin; Zhang, Xixiang; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

2016-05-01

The functional basis for species sorting theory remains elusive, especially for microbial community assembly in deep-sea environments. Using artificial surface-based biofilm models, our recent work revealed taxonomic succession during biofilm development in a newly defined cold seep system, the Thuwal cold seeps II, which comprises a brine pool and the adjacent normal bottom water (NBW) to form a metacommunity via the potential immigration of organisms from one patch to another. Here, we designed an experiment to investigate the effects of environmental switching between the brine pool and the NBW on biofilm assembly, which could reflect environmental filtering effects during bacterial immigration to new environments. Analyses of 16S rRNA genes of 71 biofilm samples suggested that the microbial composition of biofilms established in new environments was determined by both the source community and the incubation conditions. Moreover, a comparison of 18 metagenomes provided evidence for biofilm community assembly that was based primarily on functional features rather than taxonomic identities; metal ion resistance and amino acid metabolism were the major species sorting determinants for the succession of biofilm communities. Genome binning and pathway reconstruction of two bacterial species (Marinobacter sp. and Oleispira sp.) further demonstrated metal ion resistance and amino acid metabolism as functional traits conferring the survival of habitat generalists in both the brine pool and NBW. The results of this study shed new light on microbial community assembly in special habitats and bridge a gap in species sorting theory. © 2015 John Wiley & Sons Ltd.

Hydrocarbons and air pollution

International Nuclear Information System (INIS)

Herz, O.

1992-01-01

This paper shows the influence of hydrocarbons vapors, emitted by transports or by volatile solvents using, on air pollution. Hydrocarbons are the principal precursors of photochemical pollution. After a brief introduction on atmospheric chemistry and photochemical reactions, the author describes the french prevention program against hydrocarbons emissions. In the last chapter, informations on international or european community programs for photochemical pollution study are given. 5 figs., 10 tabs

V. Terrestrial vertebrates

Science.gov (United States)

Dean Pearson; Deborah Finch

2011-01-01

Within the Interior West, terrestrial vertebrates do not represent a large number of invasive species relative to invasive weeds, aquatic vertebrates, and invertebrates. However, several invasive terrestrial vertebrate species do cause substantial economic and ecological damage in the U.S. and in this region (Pimental 2000, 2007; Bergman and others 2002; Finch and...

Detection of hydrocarbons in irradiated foods

International Nuclear Information System (INIS)

Miyahara, Makoto; Maitani, Tamio; Saito, Akiko; Kamimura, Tomomi; Nagasawa, Taeko; Kobayashi, Yasuo; Ito, Hitoshi

2003-01-01

The hydrocarbon method for the detection of irradiated foods is now recognized as the international technique. This method is based on radiolysis of fatty acids in food to give hydrocarbons. In order to expand this technique's application, ten foods (butter, cheese, chicken, pork, beef, tuna, dry shrimp, avocado, papaya, and mango) were irradiated in the range from 0.5 to 10 kGy and the hydrocarbons in them were detected. Recoveries of the hydrocarbons from most foods were acceptable (38-128%). Some hydrocarbons were found in non-irradiated foods, particularly, in butter, cheese, tuna, and shrimp. Seven irradiated foods, butter, cheese, chicken, beef, pork, tuna, dry shrimp, and avocado were detectable at their practical doses by measuring the appropriate marker hydrocarbons. In most case, marker hydrocarbon will be 1,7-hexadecadiene. However, the marker hydrocarbons produced only in irradiated foods varied from food to food; therefore, it is necessary to check a specific irradiated food for marker hydrocarbons. On the other hand, two irradiated foods (papaya and mango which were irradiated at their practical doses) were difficult to distinguish from non-irradiated foods using this method. (author)

Detection of hydrocarbons in irradiated foods

Energy Technology Data Exchange (ETDEWEB)

Miyahara, Makoto; Maitani, Tamio [National Inst. of Health Sciences, Tokyo (Japan); Saito, Akiko; Kamimura, Tomomi; Nagasawa, Taeko [Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Allied Health Sciences; Kobayashi, Yasuo; Ito, Hitoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Establishment

2003-06-01

The hydrocarbon method for the detection of irradiated foods is now recognized as the international technique. This method is based on radiolysis of fatty acids in food to give hydrocarbons. In order to expand this technique's application, ten foods (butter, cheese, chicken, pork, beef, tuna, dry shrimp, avocado, papaya, and mango) were irradiated in the range from 0.5 to 10 kGy and the hydrocarbons in them were detected. Recoveries of the hydrocarbons from most foods were acceptable (38-128%). Some hydrocarbons were found in non-irradiated foods, particularly, in butter, cheese, tuna, and shrimp. Seven irradiated foods, butter, cheese, chicken, beef, pork, tuna, dry shrimp, and avocado were detectable at their practical doses by measuring the appropriate marker hydrocarbons. In most case, marker hydrocarbon will be 1,7-hexadecadiene. However, the marker hydrocarbons produced only in irradiated foods varied from food to food; therefore, it is necessary to check a specific irradiated food for marker hydrocarbons. On the other hand, two irradiated foods (papaya and mango which were irradiated at their practical doses) were difficult to distinguish from non-irradiated foods using this method. (author)

Natural Gas Seepage Along the Edge of the Aquitaine Shelf (France): Origin and Flux Measurements

Science.gov (United States)

Ruffine, L.; Donval, J. P.; Battani, A.; Bignon, L.; Croguennec, C.; Caprais, J. C.; Birot, D.; Bayon, G.; Lantéri, N.; Levaché, D.; Dupré, S.

2014-12-01

A newly discovered and highly active seepage area has been acoustically mapped at the western edge of the Aquitaine Shelf in the Bay of Biscay [Dupré et al., 2014]. Three selected seeping sites have been investigated with a Remotely Operated Vehicle. All sites were characterized by vigorous gas emissions, and the occurrence of massive carbonate crusts and bacterial mats at the seafloor. Nine seeps have been sampled with the PEGAZ sampler. The latter allowed gas-bubble sampling and preservation at in situpressure, together with gas-flux measurement through its graduated transparent cone. The C2+ fraction of the gas samples accounts for less than 0.06 %-mol of the total composition. Both the abundance of methane and dD and d13C isotopic analyses of the hydrocarbons indicate a biogenic source generated by microbial reduction of carbon dioxide [Whiticar et al., 1986]. The analyses of the associated noble gases also provide further support for a shallow-depth generation. While sharing the same origin, the collected samples are different in other respects, such as the measured d13C values for carbon dioxide and the hydrocarbons. This is the case in particular for methane, with displays values in between -66.1 and -72.7 ‰. We hypothesized that such variations are the result of multiple gas-transport processes along with the occurrence of hydrocarbon oxidation at different rates within the sedimentary column. The measured gas fluxes are extremely heterogeneous from one seep to another, ranging from 18 to 193 m3.yr-1. These values will be discussed in detail by comparing them with values obtained from different measurement techniques at other gas-seeping sites. The GAZCOGNE study is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. References:Dupré, S., L. Berger, N. Le Bouffant, C. Scalabrin, and J. F. Bourillet (2014), Fluid emissions at the Aquitaine Shelf (Bay of Biscay, France): a biogenic origin or

Production of light hydrocarbons, etc. [from heavy hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1937-10-07

A process is given for the production of light hydrocarbons of the gasoline type and, if desired, of the middle-oil type, from liquid or fusible heavy or medium heavy hydrocarbon materials. The process comprises subjecting the said initial materials in the first stage to catalytic hydrofining, separating the lower boiling constituents and the hydrogenating gas from the resulting products and then subjecting the higher boiling constituents in a second stage to a splitting destructive hydrogenation and then recycling substantially the entire reaction mixture obtained in the second stage to the frst stage.

Assessing submarine gas hydrate at active seeps on the Hikurangi Margin, New Zealand, using controlled source electromagnetic data with constraints from seismic, geochemistry, and heatflow data

Science.gov (United States)

Schwalenberg, K.; Haeckel, M.; Pecher, I. A.; Toulmin, S. J.; Hamdan, L. J.; Netzeband, G.; Wood, W.; Poort, J.; Jegen, M. D.; Coffin, R. B.

2009-12-01

Electrical resistivity is one of the key properties useful for evaluating submarine gas hydrate deposits. Gas hydrates are electrically insulating in contrast to the conductive pore fluid. Where they form in sufficient quantities the bulk resistivity of the sub-seafloor is elevated. CSEM data were collected in 2007 as part of the German - International “New Vents” project on R/V Sonne, cruise SO191, at three target areas on the Hikurangi subduction margin, New Zealand. The margin is characterized by widespread bottom simulating reflectors (BSR), seep structures, and active methane and fluid venting indicating the potential for gas hydrate formation. Opouawe Bank is one of the ridge and basin systems on the accretionary wedge and is located off the Wairarapa coast at water depths of 1000-1100 m. The first observed seep sites (North Tower, South Tower, Pukeko, Takahe, and Tui) were identified from individual gas flares in hydro-acoustic data and video observations during voyages on R/V Tangaroa. Seismic reflection data collected during SO191 subsequently identified more than 25 new seep structures. Two intersecting CSEM profiles have been surveyed across North Tower, South Tower, and Takahe. 1-D inversion of the data reveals anomalously high resistivities at North Tower and South Tower, moderately elevated resistivities at Takahe, and normal background resistivities away from the seeps. The high resistivities are attributed to gas hydrate layers at intermediate depths beneath the seeps. At South Tower the hydrate concentration could be possibly as much as 25% of the total sediment volume within a 50m thick layer. This conforms with geochemical pore water analyses which show a trend of increased methane flux towards South Tower. At Takahe, gas pockets and patchy gas hydrate, as well as sediment heterogeneities and carbonates, or temperature driven upward fluid flow indicated by the observed higher heat flow at this site may explain the resistivity pattern

Do ampharetids take sedimented steps between vents and seeps? Phylogeny and habitat-use of Ampharetidae (Annelida, Terebelliformia) in chemosynthesis-based ecosystems.

Science.gov (United States)

Eilertsen, Mari H; Kongsrud, Jon A; Alvestad, Tom; Stiller, Josefin; Rouse, Greg W; Rapp, Hans T

2017-10-31

A range of higher animal taxa are shared across various chemosynthesis-based ecosystems (CBEs), which demonstrates the evolutionary link between these habitats, but on a global scale the number of species inhabiting multiple CBEs is low. The factors shaping the distributions and habitat specificity of animals within CBEs are poorly understood, but geographic proximity of habitats, depth and substratum have been suggested as important. Biogeographic studies have indicated that intermediate habitats such as sedimented vents play an important part in the diversification of taxa within CBEs, but this has not been assessed in a phylogenetic framework. Ampharetid annelids are one of the most commonly encountered animal groups in CBEs, making them a good model taxon to study the evolution of habitat use in heterotrophic animals. Here we present a review of the habitat use of ampharetid species in CBEs, and a multi-gene phylogeny of Ampharetidae, with increased taxon sampling compared to previous studies. The review of microhabitats showed that many ampharetid species have a wide niche in terms of temperature and substratum. Depth may be limiting some species to a certain habitat, and trophic ecology and/or competition are identified as other potentially relevant factors. The phylogeny revealed that ampharetids have adapted into CBEs at least four times independently, with subsequent diversification, and shifts between ecosystems have happened in each of these clades. Evolutionary transitions are found to occur both from seep to vent and vent to seep, and the results indicate a role of sedimented vents in the transition between bare-rock vents and seeps. The high number of ampharetid species recently described from CBEs, and the putative new species included in the present phylogeny, indicates that there is considerable diversity still to be discovered. This study provides a molecular framework for future studies to build upon and identifies some ecological and

Terrestrial Analogs to Mars

Science.gov (United States)

Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.

2002-08-01

It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

Versatility of hydrocarbon production in cyanobacteria.

Science.gov (United States)

Xie, Min; Wang, Weihua; Zhang, Weiwen; Chen, Lei; Lu, Xuefeng

2017-02-01

Cyanobacteria are photosynthetic microorganisms using solar energy, H 2 O, and CO 2 as the primary inputs. Compared to plants and eukaryotic microalgae, cyanobacteria are easier to be genetically engineered and possess higher growth rate. Extensive genomic information and well-established genetic platform make cyanobacteria good candidates to build efficient biosynthetic pathways for biofuels and chemicals by genetic engineering. Hydrocarbons are a family of compounds consisting entirely of hydrogen and carbon. Structural diversity of the hydrocarbon family is enabled by variation in chain length, degree of saturation, and rearrangements of the carbon skeleton. The diversified hydrocarbons can be used as valuable chemicals in the field of food, fuels, pharmaceuticals, nutrition, and cosmetics. Hydrocarbon biosynthesis is ubiquitous in bacteria, yeasts, fungi, plants, and insects. A wide variety of pathways for the hydrocarbon biosynthesis have been identified in recent years. Cyanobacteria may be superior chassis for hydrocabon production in a photosynthetic manner. A diversity of hydrocarbons including ethylene, alkanes, alkenes, and terpenes can be produced by cyanobacteria. Metabolic engineering and synthetic biology strategies can be employed to improve hydrocarbon production in cyanobacteria. This review mainly summarizes versatility and perspectives of hydrocarbon production in cyanobacteria.

Cold seeps in Monterey Bay, California: Geochemistry of pore waters and relationship to benthic foraminiferal calcite

International Nuclear Information System (INIS)

Gieskes, Joris; Rathburn, Anthony E.; Martin, Jonathan B.; Perez, M. Elena; Mahn, Chris; Bernhard, Joan M.; Day, Shelley

2011-01-01

Highlights: → We describe the geochemistry of pore waters in the Clam Flats area of Monterey Bay. → The geochemical data are compared with the δ 13 C chemistry of benthic foraminifera. → Living foraminifera indicate little effects of pore water low δ 13 C (DIC) in the clam bed. → This phenomenon and its implications are discussed in detail. → Implications with regards to paleo-methane seepage are discussed. - Abstract: An extensive geochemical and biogeochemical examination of CH 4 seeps in the Clam Flats area of Monterey Bay provides insight into the character of relationships between seep geochemistry and benthic foraminiferal geochemistry. The area is characterized by sulfide-rich fluids. Sulfide increases are associated with large increases in alkalinity, as well as small decreases in dissolved Ca and Mg. In addition, only small increases in NH 4 are observed, but values of δ 13 C of dissolved inorganic C are as low as -60 per mille at shallow depths ( 4 , which is transported upward by slow seepage of pore fluids. The geochemistry of the pore fluids should be relevant to the geochemistry of the carbonate tests of living and dead foraminifera. However, a profound disequilibrium of approximately an order of magnitude occurs between the δ 13 C values of stained (cytoplasm-containing) foraminiferal carbonate and the C isotope values of ambient pore water dissolved inorganic C. Reasons are unclear for this isotopic disequilibrium, but have important implications for interpretations of foraminiferal carbonate as a paleoenvironmental proxy. Much fine scale work is needed to fully understand the relationships between the biogeochemistry of benthic foraminifera and the geochemistry of the pore waters where they live.

Contrasting the community structure of arbuscular mycorrhizal fungi from hydrocarbon-contaminated and uncontaminated soils following willow (Salix spp. L. planting.

Directory of Open Access Journals (Sweden)

Saad El-Din Hassan

Full Text Available Phytoremediation is a potentially inexpensive alternative to chemical treatment of hydrocarbon-contaminated soils, but its success depends heavily on identifying factors that govern the success of root-associated microorganisms involved in hydrocarbon degradation and plant growth stimulation. Arbuscular mycorrhizal fungi (AMF form symbioses with many terrestrial plants, and are known to stimulate plant growth, although both species identity and the environment influence this relationship. Although AMF are suspected to play a role in plant adaptation to hydrocarbon contamination, their distribution in hydrocarbon-contaminated soils is not well known. In this study, we examined how AMF communities were structured within the rhizosphere of 11 introduced willow cultivars as well as unplanted controls across uncontaminated and hydrocarbon-contaminated soils at the site of a former petrochemical plant. We obtained 69 282 AMF-specific 18S rDNA sequences using 454-pyrosequencing, representing 27 OTUs. Contaminant concentration was the major influence on AMF community structure, with different AMF families dominating at each contaminant level. The most abundant operational taxonomic unit in each sample represented a large proportion of the total community, and this proportion was positively associated with increasing contamination, and seemingly, by planting as well. The most contaminated soils were dominated by three phylotypes closely related to Rhizophagus irregularis, while these OTUs represented only a small proportion of sequences in uncontaminated and moderately contaminated soils. These results suggest that in situ inoculation of AMF strains could be an important component of phytoremediation treatments, but that strains should be selected from the narrow group that is both adapted to contaminant toxicity and able to compete with indigenous AMF species.

Contrasting the community structure of arbuscular mycorrhizal fungi from hydrocarbon-contaminated and uncontaminated soils following willow (Salix spp. L.) planting.

Science.gov (United States)

Hassan, Saad El-Din; Bell, Terrence H; Stefani, Franck O P; Denis, David; Hijri, Mohamed; St-Arnaud, Marc

2014-01-01

Phytoremediation is a potentially inexpensive alternative to chemical treatment of hydrocarbon-contaminated soils, but its success depends heavily on identifying factors that govern the success of root-associated microorganisms involved in hydrocarbon degradation and plant growth stimulation. Arbuscular mycorrhizal fungi (AMF) form symbioses with many terrestrial plants, and are known to stimulate plant growth, although both species identity and the environment influence this relationship. Although AMF are suspected to play a role in plant adaptation to hydrocarbon contamination, their distribution in hydrocarbon-contaminated soils is not well known. In this study, we examined how AMF communities were structured within the rhizosphere of 11 introduced willow cultivars as well as unplanted controls across uncontaminated and hydrocarbon-contaminated soils at the site of a former petrochemical plant. We obtained 69 282 AMF-specific 18S rDNA sequences using 454-pyrosequencing, representing 27 OTUs. Contaminant concentration was the major influence on AMF community structure, with different AMF families dominating at each contaminant level. The most abundant operational taxonomic unit in each sample represented a large proportion of the total community, and this proportion was positively associated with increasing contamination, and seemingly, by planting as well. The most contaminated soils were dominated by three phylotypes closely related to Rhizophagus irregularis, while these OTUs represented only a small proportion of sequences in uncontaminated and moderately contaminated soils. These results suggest that in situ inoculation of AMF strains could be an important component of phytoremediation treatments, but that strains should be selected from the narrow group that is both adapted to contaminant toxicity and able to compete with indigenous AMF species.

Predicting hydrocarbon release from soil

International Nuclear Information System (INIS)

Poppendieck, D.; Loehr, R.C.

2002-01-01

'Full text:' The remediation of hazardous chemicals from soils can be a lengthy and costly process. As a result, recent regulatory initiatives have focused on risk-based corrective action (RBCA) approaches. Such approaches attempt to identify the amount of chemical that can be left at a site with contaminated soil and still be protective of human health and the environment. For hydrocarbons in soils to pose risk to human heath and the environment, the hydrocarbons must be released from the soil and accessible to microorganisms, earthworms, or other higher level organisms. The sorption of hydrocarbons to soil can reduce the availability of the hydrocarbon to receptors. Typically in soils and sediments, there is an initial fast release of a hydrocarbon from the soil to the aqueous phase followed by a slower release of the remaining hydrocarbon to the aqueous phase. The rate and extent of slow release can influence aqueous hydrocarbon concentrations and the fate and transport of hydrocarbons in the subsurface. Once the fast fraction of the chemical has been removed from the soil, the remaining fraction of a chemical may desorb at a rate that natural mechanisms can attenuate the released hydrocarbon. Hence, active remediation may be needed only until the fast fraction has been removed. However, the fast fraction is a soil and chemical specific parameter. This presentation will present a tier I type protocol that has been developed to quickly estimate the fraction of hydrocarbons that are readily released from the soil matrix to the aqueous phase. Previous research in our laboratory and elsewhere has used long-term desorption (four months) studies to determine the readily released fraction. This research shows that a single short-term (less than two weeks) batch extraction procedure provides a good estimate of the fast released fraction derived from long-term experiments. This procedure can be used as a tool to rapidly evaluate the release and bioavailability of

Exploratory Data Analysis of Synthetic Aperture Radar (SAR Measurements to Distinguish the Sea Surface Expressions of Naturally-Occurring Oil Seeps from Human-Related Oil Spills in Campeche Bay (Gulf of Mexico

Directory of Open Access Journals (Sweden)

Gustavo de Araújo Carvalho

2017-12-01

Full Text Available An Exploratory Data Analysis (EDA aims to use Synthetic Aperture Radar (SAR measurements for discriminating between two oil slick types observed on the sea surface: naturally-occurring oil seeps versus human-related oil spills—the use of satellite sensors for this task is poorly documented in scientific literature. A long-term RADARSAT dataset (2008–2012 is exploited to investigate oil slicks in Campeche Bay (Gulf of Mexico. Simple Classification Algorithms to distinguish the oil slick type are designed based on standard multivariate data analysis techniques. Various attributes of geometry, shape, and dimension that describe the oil slick Size Information are combined with SAR-derived backscatter coefficients—sigma-(σo, beta-(βo, and gamma-(γo naught. The combination of several of these characteristics is capable of distinguishing the oil slick type with ~70% of overall accuracy, however, the sole and simple use of two specific oil slick’s Size Information (i.e., area and perimeter is equally capable of distinguishing seeps from spills. The data mining exercise of our EDA promotes a novel idea bridging petroleum pollution and remote sensing research, thus paving the way to further investigate the satellite synoptic view to express geophysical differences between seeped and spilled oil observed on the sea surface for systematic use.

Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1927-02-22

Coal tar, mineral oils, bitumens, coal extraction products, hydrogenation products of coal, oil schists can be atomized and heated with steam to decompose pyrogenetically and form gases rich in olefins which may be heated with or without pressure and with or without catalysts to produce liquid hydrocarbons of low boiling point, some of which may be aromatic. The apparatus should be lined with copper, silica, or ferrosilicon to prevent contact of the bases with iron which causes deposition of soot. Catalysts used may be metal oxides, silica, graphite, active charcoal, mica, pumice, porcelain, barium carbonate, copper, silver, gold, chromium, boron, or their compounds. At temperatures from 300 to 400/sup 0/C, olefins are produced. At higher temperatures, naphthenes and benzene hydrocarbons are produced.

Hydrocarbon degraders establish at the costs of microbial richness, abundance and keystone taxa after crude oil contamination in permafrost environments

Science.gov (United States)

Yang, Sizhong; Wen, Xi; Shi, Yulan; Liebner, Susanne; Jin, Huijun; Perfumo, Amedea

2016-01-01

Oil spills from pipeline ruptures are a major source of terrestrial petroleum pollution in cold regions. However, our knowledge of the bacterial response to crude oil contamination in cold regions remains to be further expanded, especially in terms of community shifts and potential development of hydrocarbon degraders. In this study we investigated changes of microbial diversity, population size and keystone taxa in permafrost soils at four different sites along the China-Russia crude oil pipeline prior to and after perturbation with crude oil. We found that crude oil caused a decrease of cell numbers together with a reduction of the species richness and shifts in the dominant phylotypes, while bacterial community diversity was highly site-specific after exposure to crude oil, reflecting different environmental conditions. Keystone taxa that strongly co-occurred were found to form networks based on trophic interactions, that is co-metabolism regarding degradation of hydrocarbons (in contaminated samples) or syntrophic carbon cycling (in uncontaminated samples). With this study we demonstrate that after severe crude oil contamination a rapid establishment of endemic hydrocarbon degrading communities takes place under favorable temperature conditions. Therefore, both endemism and trophic correlations of bacterial degraders need to be considered in order to develop effective cleanup strategies. PMID:27886221

Fractional separation of hydrocarbon vapours

Energy Technology Data Exchange (ETDEWEB)

1937-07-10

A process is described for converting higher boiling hydrocarbons to lower boiling hydrocarbons by subjecting them at elevated temperatures to a conversion operation, then separating the higher and lower boiling fractions. The separation takes place while the reaction products are maintained in the vapor phase by contact with a mass of solid porous material which has little or no catalytic activity but does have a preferential absorption property for higher boiling hydrocarbons so that the lower boiling part of the reaction products pass through the separation zone while the heavier hydrocarbons are retained. The separation is accomplished without substantial loss of heat of these reaction products.

Net Ecosystem Fluxes of Hydrocarbons from a Ponderosa Pine Forest in Colorado

Science.gov (United States)

Rhew, R. C.; Turnipseed, A. A.; Ortega, J. V.; Smith, J. N.; Guenther, A. B.; Shen, S.; Martinez, L.; Koss, A.; Warneke, C.; De Gouw, J. A.; Deventer, M. J.

2015-12-01

Light (C2-C4) alkenes, light alkanes and isoprene (C5H8) are non-methane hydrocarbons that play important roles in the photochemical production of tropospheric ozone and in the formation of secondary organic aerosols. Natural terrestrial fluxes of the light hydrocarbons are poorly characterized, with global emission estimates based on limited field measurements. In 2014, net fluxes of these compounds were measured at the Manitou Experimental Forest Observatory, a semi-arid ponderosa pine forest in the Colorado Rocky Mountains and site of the prior BEACHON campaigns. Three field intensives were conducted between June 17 and August 10, 2014. Net ecosystem flux measurements utilized a relaxed eddy accumulation system coupled to an automated gas chromatograph. Summertime average emissions of ethene and propene were up to 90% larger than those observed from a temperate deciduous forest. Ethene and propene fluxes were also correlated to each other, similar to the deciduous forest study. Emissions of isoprene were small, as expected for a coniferous forest, and these fluxes were not correlated with either ethene or propene. Unexpected emissions of light alkanes were also observed, and these showed a distinct diurnal cycle. Understory flux measurements allowed for the partitioning of fluxes between the surface and the canopy. Full results from the three field intensives will be compared with environmental variables in order to parameterize the fluxes for use in modeling emissions.

Mega Borg oil spill of the Texas coast: An open-water bioremediation test

International Nuclear Information System (INIS)

Oppenheimer, C.H.

1991-01-01

Nature has developed hydrocarbons as a part of life. Since the origin of life, more than 60,000 organic molecules have evolved that make up protoplasm; a given percentage of these molecules are hydrocarbons. Commercial hydrocarbon deposits are a by-product of this natural process and a continual source of oil in the aquatic environment through seeps. As a result, nature has also evolved a recycling system for the hydrocarbons. This cycle is the basis for a program of bioremediation using microorganisms. Effort has been made to develop mixed cultures capable of a wide range of hydrocarbon metabolism and co-metabolism. The cultures are economically produced in high concentrations as a dry powder with a shelf life of one year. The result is an economical process for the application of bacteria to hydrocarbon pollutants on water and soils. The process of bioremediation to the recent Mega Borg accident will be discussed

Bioremediation of soils containing petroleum hydrocarbons, chlorinated phenols, and polycyclic aromatic hydrocarbons

International Nuclear Information System (INIS)

Seech, A.; Burwell, S.; Marvan, I.

1994-01-01

Bench-scale treatability investigations, pilot-scale and full-scale bioremediation projects were conducted to evaluate Daramend trademark bioremediation of soils containing petroleum hydrocarbons, heavy oils, paraffins, chlorinated phenols and polycyclic aromatic hydrocarbons (PAHs). Bench-scale investigations were conducted using glass microcosms. Pilot-scale and full-scale demonstrations were conducted at industrial sites and included treatment of excavated soils and sediments in on-site cells constructed using synthetic liners and covered by steel/polyethylene structures as well as in-situ treatment. A total of approximately 5,000 tons of soil was treated. The soil treatment included organic soil amendments, specialized tillage/aeration apparatus, and strict control of soil moisture. The amendments are composed of naturally-occurring organic materials prepared to soil-specific particle size distributions, nutrient profiles, and nutrient-release kinetics. Bench-scale work indicated that in refinery soil containing high concentrations of heavy oils, extractable hydrocarbon concentrations could be rapidly reduced to industrial clean-up criteria, and that the hydrocarbons were fully mineralized with release of CO 2

Bacterial diversity and biogeochemistry of different chemosynthetic habitats of the REGAB cold seep (West African margin, 3160 m water depth

Directory of Open Access Journals (Sweden)

P. Pop Ristova

2012-12-01

Full Text Available The giant pockmark REGAB (West African margin, 3160 m water depth is an active methane-emitting cold seep ecosystem, where the energy derived from microbially mediated oxidation of methane supports high biomass and diversity of chemosynthetic communities. Bare sediments interspersed with heterogeneous chemosynthetic assemblages of mytilid mussels, vesicomyid clams and siboglinid tubeworms form a complex seep ecosystem. To better understand if benthic bacterial communities reflect the patchy distribution of chemosynthetic fauna, all major chemosynthetic habitats at REGAB were investigated using an interdisciplinary approach combining pore water geochemistry, in situ quantification of fluxes and consumption of methane, as well as bacterial community fingerprinting. This study revealed that sediments populated by different fauna assemblages show distinct biogeochemical activities and are associated with distinct sediment bacterial communities. The methane consumption rates and methane effluxes ranged over one to two orders of magnitude across habitats, and reached highest values at the mussel habitat, which hosted a different bacterial community compared to the other habitats. Clam assemblages had a profound impact on the sediment geochemistry, but less so on the bacterial community structure. Moreover, all clam assemblages at REGAB were restricted to sediments characterized by complete methane consumption in the seafloor, and intermediate biogeochemical activity. Overall, variations in the sediment geochemistry were reflected in the distribution of both fauna and microbial communities; and were mostly determined by methane flux.

Characterization of hydrocarbon utilizing fungi from hydrocarbon ...

African Journals Online (AJOL)

Prof. Ogunji

isolated fungi could be useful in the bioremediation of hydrocarbon polluted sites. Keywords: ... Technologies such as mechanical force, burying, evaporation, dispersant application, and ..... The effects of drilling fluids on marine bacteria from a.

Measuring Trace Hydrocarbons in Silanes

Science.gov (United States)

Lesser, L. A.

1984-01-01

Technique rapid and uses standard analytical equipment. Silane gas containing traces of hydrocarbons injected into carrier gas of moist nitrogen having about 0.2 percent water vapor. Carrier, water and silane pass through short column packed with powdered sodium hydroxide which combines moisture and silane to form nonvolatile sodium silicate. Carrier gas free of silane but containing nonreactive hydrocarbons, pass to silica-gel column where chromatographic separation takes place. Hydrocarbons measured by FID.

Cold seeps in Monterey Bay, California: Geochemistry of pore waters and relationship to benthic foraminiferal calcite

Energy Technology Data Exchange (ETDEWEB)

Gieskes, Joris, E-mail: jgieskes@ucsd.edu [Scripps Institution of Oceanography, IOD-0208, 9500 Gilman Drive, La Jolla, CA 92093-0208 (United States); Rathburn, Anthony E. [Scripps Institution of Oceanography, IOD-0208, 9500 Gilman Drive, La Jolla, CA 92093-0208 (United States)] [Indiana State University, Department of Earth and Environmental Systems, Terre Haute, IN 47809 (United States); Martin, Jonathan B. [University of Florida, Department of Geological Sciences, Gainesville, FL 32611-2120 (United States); Perez, M. Elena [Indiana State University, Department of Earth and Environmental Systems, Terre Haute, IN 47809 (United States)] [The Natural History Museum, Department of Palaeontology, Cromwell Road, London SW7 5BD (United Kingdom); Mahn, Chris [Scripps Institution of Oceanography, IOD-0208, 9500 Gilman Drive, La Jolla, CA 92093-0208 (United States); Bernhard, Joan M. [Woods Hole Oceanographic Institution, Geology and Geophysics Department, MS52, Woods Hole, MA 02543 (United States); Day, Shelley [University of Florida, Department of Geological Sciences, Gainesville, FL 32611-2120 (United States)

2011-05-15

Highlights: > We describe the geochemistry of pore waters in the Clam Flats area of Monterey Bay. > The geochemical data are compared with the {delta}{sup 13}C chemistry of benthic foraminifera. > Living foraminifera indicate little effects of pore water low {delta}{sup 13}C (DIC) in the clam bed. > This phenomenon and its implications are discussed in detail. > Implications with regards to paleo-methane seepage are discussed. - Abstract: An extensive geochemical and biogeochemical examination of CH{sub 4} seeps in the Clam Flats area of Monterey Bay provides insight into the character of relationships between seep geochemistry and benthic foraminiferal geochemistry. The area is characterized by sulfide-rich fluids. Sulfide increases are associated with large increases in alkalinity, as well as small decreases in dissolved Ca and Mg. In addition, only small increases in NH{sub 4} are observed, but values of {delta}{sup 13}C of dissolved inorganic C are as low as -60 per mille at shallow depths (<3 cm). These observations indicate that all these processes are related to the bacterial oxidation of CH{sub 4}, which is transported upward by slow seepage of pore fluids. The geochemistry of the pore fluids should be relevant to the geochemistry of the carbonate tests of living and dead foraminifera. However, a profound disequilibrium of approximately an order of magnitude occurs between the {delta}{sup 13}C values of stained (cytoplasm-containing) foraminiferal carbonate and the C isotope values of ambient pore water dissolved inorganic C. Reasons are unclear for this isotopic disequilibrium, but have important implications for interpretations of foraminiferal carbonate as a paleoenvironmental proxy. Much fine scale work is needed to fully understand the relationships between the biogeochemistry of benthic foraminifera and the geochemistry of the pore waters where they live.

Terrestrial planet formation.

Science.gov (United States)

Righter, K; O'Brien, D P

2011-11-29

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

Purifying hydrocarbon oils

Energy Technology Data Exchange (ETDEWEB)

Rostin, H

1938-08-11

A process is described for continuously purifying hydrocarbon oils consisting in conducting the vapors of the same at a temperature of 300 to 400/sup 0/C over the oelitic ore minette together with reducing gases in presence of steam the proportion of the reducing gases and steam being such that the sulfur of the hydrocarbons escapes from the reaction chamber in the form of sulfuretted hydrogen without permanent sulfide of iron being formed.

Gully formation in terrestrial simple craters: Meteor Crater, USA and Lonar Crater, India

Science.gov (United States)

Kumar, P.; Head, J. W.; Kring, D. A.

2007-12-01

Geomorphic features such as gullies, valley networks, and channels on Mars have been used as a proxy to understand the climate and landscape evolution of Mars. Terrestrial analogues provide significant insight as to how the various exogenic and endogenic processes might contribute to the evolution of these martian landscapes. We describe here a terrestrial example from Meteor Crater, which shows a spectacular development of gullies throughout the inner wall in response to rainwater precipitation, snow melting and groundwater discharge. As liquid water has been envisaged as one of the important agents of landscape sculpturing, Meteor Crater remains a useful landmark, where planetary geologists can learn some lessons. We also show here how the lithology and structural framework of this crater controls the gully distribution. Like many martian impact craters, it was emplaced in layered sedimentary rocks with an exceptionally well-developed centripetal drainage pattern consisting of individual alcoves, channels and fans. Some of the gullies originate from the rim crest and others from the middle crater wall, where a lithologic transition occurs. Deeply incised alcoves are well-developed on the soft sandstones of the Coconino Formation exposed on the middle crater wall, beneath overlying dolomite. In general, the gully locations are along crater wall radial fractures and faults, which are favorable locales of groundwater flow and discharge; these structural discontinuities are also the locales where the surface runoff from rain precipitation and snow melting can preferentially flow, causing degradation. Like martian craters, channels are well developed on the talus deposits and alluvial fans on the periphery of the crater floor. In addition, lake sediments on the crater floor provide significant evidence of a past pluvial climate, when groundwater seeped from springs on the crater wall. Caves exposed on the lower crater level may point to percolation of surface runoff

Recovering low-boiling hydrocarbons, etc

Energy Technology Data Exchange (ETDEWEB)

Pier, M

1934-10-03

A process is described for the recovery of low-boiling hydrocarbons of the nature of benzine through treatment of liquid carbonaceous materials with hydrogen under pressure at raised temperature, suitably in the presence of catalysts. Middle oils (practically saturated with hydrogen) or higher boiling oils at a temperature above 500/sup 0/ (with or without the addition of hydrogen) containing cyclic hydrocarbons not saturated with hydrogen are changed into low boiling hydrocarbons of the nature of benzine. The cracking takes place under strongly hydrogenating conditions (with the use of a strongly active hydrogenating catalyst or high pressure) at temperatures below 500/sup 0/. If necessary, the constituents boiling below 200/sup 0/ can be reconverted into cyclic hydrocarbons partially saturated with hydrogen. (BLM)

Consequences of simulating terrestrial N dynamics for projecting future terrestrial C storage

Science.gov (United States)

Zaehle, S.; Friend, A. D.; Friedlingstein, P.

2009-04-01

We present results of a new land surface model, O-CN, which includes a process-based coupling between the terrestrial cycling of energy, water, carbon, and nitrogen. The model represents the controls of the terrestrial nitrogen (N) cycling on carbon (C) pools and fluxes through photosynthesis, respiration, changes in allocation patterns, as well as soil organic matter decomposition, and explicitly accounts for N leaching and gaseous losses. O-CN has been shown to give realistic results in comparison to observations at a wide range of scales, including in situ flux measurements, productivity databases, and atmospheric CO2 concentration data. Notably, O-CN simulates realistic responses of net primary productivity, foliage area, and foliage N content to elevated atmospheric [CO2] as evidenced at free air carbon dioxide enrichment (FACE) sites (Duke, Oak Ridge). We re-examine earlier model-based assessments of the terrestrial C sequestration potential using a global transient O-CN simulation driven by increases in atmospheric [CO2], N deposition and climatic changes over the 21st century. We find that accounting for terrestrial N cycling about halves the potential to store C in response to increases in atmospheric CO2 concentrations; mainly due to a reduction of the net C uptake in temperate and boreal forests. Nitrogen deposition partially alleviates the effect of N limitation, but is by far not sufficient to compensate for the effect completely. These findings underline the importance of an accurate representation of nutrient limitations in future projections of the terrestrial net CO2 exchanges and therefore land-climate feedback studies.

Hydrous pyrolysis/oxidation process for in situ destruction of chlorinated hydrocarbon and fuel hydrocarbon contaminants in water and soil

Science.gov (United States)

Knauss, Kevin G.; Copenhaver, Sally C.; Aines, Roger D.

2000-01-01

In situ hydrous pyrolysis/oxidation process is useful for in situ degradation of hydrocarbon water and soil contaminants. Fuel hydrocarbons, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, petroleum distillates and other organic contaminants present in the soil and water are degraded by the process involving hydrous pyrolysis/oxidation into non-toxic products of the degradation. The process uses heat which is distributed through soils and water, optionally combined with oxygen and/or hydrocarbon degradation catalysts, and is particularly useful for remediation of solvent, fuel or other industrially contaminated sites.

Syntrophic biodegradation of hydrocarbon contaminants.

Science.gov (United States)

Gieg, Lisa M; Fowler, S Jane; Berdugo-Clavijo, Carolina

2014-06-01

Anaerobic environments are crucial to global carbon cycling wherein the microbial metabolism of organic matter occurs under a variety of redox conditions. In many anaerobic ecosystems, syntrophy plays a key role wherein microbial species must cooperate, essentially as a single catalytic unit, to metabolize substrates in a mutually beneficial manner. Hydrocarbon-contaminated environments such as groundwater aquifers are typically anaerobic, and often methanogenic. Syntrophic processes are needed to biodegrade hydrocarbons to methane, and recent studies suggest that syntrophic hydrocarbon metabolism can also occur in the presence of electron acceptors. The elucidation of key features of syntrophic processes in defined co-cultures has benefited greatly from advances in 'omics' based tools. Such tools, along with approaches like stable isotope probing, are now being used to monitor carbon flow within an increasing number of hydrocarbon-degrading consortia to pinpoint the key microbial players involved in the degradative pathways. The metagenomic sequencing of hydrocarbon-utilizing consortia should help to further identify key syntrophic features and define microbial interactions in these complex communities. Copyright © 2013 Elsevier Ltd. All rights reserved.

High-resolution gas chromatographic analysis of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons

International Nuclear Information System (INIS)

Perez, M.; Gonzalez, D.

1988-01-01

A study of the analysis by gas chromatography of aromatic polycyclic hydrocarbons and aliphatic hydrocarbons is presented. The separation has been carried out by glass and fused silica capillary column in two different polar stationary phases OV-1 and SE-54. The limitation and the advantages of the procedure are discussed in terms of separation, sensitivity and precision. (Author) 20 refs

Hydrocarbon pollution from marinas in estuarine sediments

Science.gov (United States)

Voudrias, Evangelos A.; Smith, Craig L.

1986-03-01

A measure of the impact of marinas on three Eastern Virginia estuarine creeks was obtained by a study of hydrocarbons in their sediments. Two of the creeks support considerable marine activity, including pleasure boat marinas, boat repair facilities, and commercial fishing operations. The third creek, which served as a control, is seldom used by boats, and is surrounded by marsh and woodland. Sediments from the creeks with marinas contained significantly higher levels of both aromatic and aliphatic hydrocarbons than did the control. Differences in the concentrations of certain oil-pollution indicators, such as the 17α,21β-hopane homologs and phytane, and low molecular weight aromatic hydrocarbons, are indicative of light petroleum fractions. Most of the aromatic hydrocarbons from all creeks, however, appear to have a pyrogenic origin. Although hydrocarbons from three probable origins (petroleum, pyrogenesis, and recent biosynthesis) were detected in all locations, the petroleum-derived and pyrogenic hydrocarbons were of only minor importance relative to the biogenic hydrocarbons in the control creek.

BIOREMEDIATION OF A PETROLEUM-HYDROCARBON

African Journals Online (AJOL)

ES OBE

under field conditions in the bioremediation of a petroleum- hydrocarbon polluted ... an accelerated biodegradation of petroleum hydrocarbons in a polluted agricultural soil ..... 12) Jackson, M.L. Soil chemical analysis. ... biological assay. 3 rd.

Insights into methane dynamics from analysis of authigenic carbonates and chemosynthetic mussels at newly-discovered Atlantic Margin seeps

Science.gov (United States)

Prouty, Nancy G.; Sahy, Diana; Ruppel, Carolyn D.; Roark, E. Brendan; Condon, Dan; Brooke, Sandra; Ross, Steve W.; Demopoulos, Amanda W.J.

2016-01-01

The recent discovery of active methane venting along the US northern and mid-Atlantic margin represents a new source of global methane not previously accounted for in carbon budgets from this region. However, uncertainty remains as to the origin and history of methane seepage along this tectonically inactive passive margin. Here we present the first isotopic analyses of authigenic carbonates and methanotrophic deep-sea mussels, Bathymodiolus   sp., and the first direct constraints on the timing of past methane emission, based on samples collected at the upper slope Baltimore Canyon (∼385 m water depth) and deepwater Norfolk (∼1600 m) seep fields within the area of newly-discovered venting. The authigenic carbonates at both sites were dominated by aragonite, with an average  signature of −47‰, a value consistent with microbially driven anaerobic oxidation of methane-rich fluids occurring at or near the sediment–water interface. Authigenic carbonate U and Sr isotope data further support the inference of carbonate precipitation from seawater-derived fluids rather than from formation fluids from deep aquifers. Carbonate stable and radiocarbon ( and ) isotope values from living Bathymodiolus   sp. specimens are lighter than those of seawater dissolved inorganic carbon, highlighting the influence of fossil carbon from methane on carbonate precipitation. U–Th dates on authigenic carbonates suggest seepage at Baltimore Canyon between 14.7±0.6 ka to 15.7±1.6 ka, and at the Norfolk seep field between 1.0±0.7 ka to 3.3±1.3 ka, providing constraint on the longevity of methane efflux at these sites. The age of the brecciated authigenic carbonates and the occurrence of pockmarks at the Baltimore Canyon upper slope could suggest a link between sediment delivery during Pleistocene sea-level lowstand, accumulation of pore fluid overpressure from sediment compaction, and release of overpressure through subsequent venting. Calculations show that

Optrode for sensing hydrocarbons

Science.gov (United States)

Miller, H.; Milanovich, F.P.; Hirschfeld, T.B.; Miller, F.S.

1988-09-13

A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon and but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons. 5 figs.

Biodegradation of petroleum hydrocarbons in hypersaline environments

Directory of Open Access Journals (Sweden)

Luiz Fernando Martins

2012-09-01

Full Text Available Literature on hydrocarbon degradation in extreme hypersaline media presents studies that point to a negative effect of salinity increase on hydrocarbonoclastic activity, while several others report an opposite tendency. Based on information available in the literature, we present a discussion on the reasons that justify these contrary results. Despite the fact that microbial ability to metabolize hydrocarbons is found in extreme hypersaline media, indeed some factors are critical for the occurrence of hydrocarbon degradation in such environments. How these factors affect hydrocarbon degradation and their implications for the assessment of hydrocarbon biodegradation in hypersaline environments are presented in this review.

Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

Science.gov (United States)

Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

2015-12-01

Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

Aquatic and Terrestrial Environment 2004

DEFF Research Database (Denmark)

Andersen, J. M.; Boutrup, S.; Bijl, L. van der

This report presents the 2004 results of the Danish National Monitoring and Assess-ment Programme for the Aquatic and Terrestrial Environments (NOVANA). 2004 was the first year in which terrestrial nature was included in the monitoring pro-gramme. The report reviews the state of the groundwater......, watercourses, lakes and marine waters and the pressures upon them and reviews the monitoring of terrestrial natural habitats and selected plants and animals. The report is based on the annual reports prepared for each subprogramme by the Topic Centres. The latter reports are mainly based on data collected...

Transport of terrigenous polycyclic aromatic hydrocarbons affected by the coastal upwelling in the northwestern coast of South China Sea.

Science.gov (United States)

Ya, Miaolei; Wu, Yuling; Li, Yongyu; Wang, Xinhong

2017-10-01

Coastal upwelling prevails in the coast of Hainan Island, the northern South China Sea (SCS) during summer. We studied the influences of the upwelling on the horizontal and vertical transport of terrigenous polycyclic aromatic hydrocarbons (PAHs). PAHs in dissolved and suspended particulate phase of water samples were determined in the upper (depth  10 m). PAH levels decreased sharply from inshore to offshore to open sea. The results showed that terrestrial input was the main source of coastal PAHs. Perylene, an important indicator of land plant-derived PAH, showed the significant correlation with PAHs (p sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anthropogenic transformation of the terrestrial biosphere.

Science.gov (United States)

Ellis, Erle C

2011-03-13

Human populations and their use of land have transformed most of the terrestrial biosphere into anthropogenic biomes (anthromes), causing a variety of novel ecological patterns and processes to emerge. To assess whether human populations and their use of land have directly altered the terrestrial biosphere sufficiently to indicate that the Earth system has entered a new geological epoch, spatially explicit global estimates of human populations and their use of land were analysed across the Holocene for their potential to induce irreversible novel transformation of the terrestrial biosphere. Human alteration of the terrestrial biosphere has been significant for more than 8000 years. However, only in the past century has the majority of the terrestrial biosphere been transformed into intensively used anthromes with predominantly novel anthropogenic ecological processes. At present, even were human populations to decline substantially or use of land become far more efficient, the current global extent, duration, type and intensity of human transformation of ecosystems have already irreversibly altered the terrestrial biosphere at levels sufficient to leave an unambiguous geological record differing substantially from that of the Holocene or any prior epoch. It remains to be seen whether the anthropogenic biosphere will be sustained and continue to evolve.

Histories of terrestrial planets

International Nuclear Information System (INIS)

Benes, K.

1981-01-01

The uneven historical development of terrestrial planets - Mercury, Venus, Earth, Moon and Mars - is probably due to the differences in their size, weight and rotational dynamics in association with the internal planet structure, their distance from the Sun, etc. A systematic study of extraterrestrial planets showed that the time span of internal activity was not the same for all bodies. It is assumed that the initial history of all terrestrial planets was marked with catastrophic events connected with the overall dynamic development of the solar system. In view of the fact that the cores of small terrestrial bodies cooled quicker, their geological development almost stagnated after two or three thousand million years. This is what probably happened to the Mercury and the Moon as well as the Mars. Therefore, traces of previous catastrophic events were preserved on the surface of the planets. On the other hand, the Earth is the most metamorphosed terrestrial planet and compared to the other planets appears to be atypical. Its biosphere is significantly developed as well as the other shell components, its hydrosphere and atmosphere, and its crust is considerably differentiated. (J.P.)

Process for separating liquid hydrocarbons from waxes

Energy Technology Data Exchange (ETDEWEB)

Sowa, F J

1948-03-08

A process is described for the separation of liquid hydrocarbons from waxes comprising adding to a mixture of liquid hydrocarbons and waxes a sufficient quantity of an organo-silicon compound to cause the separation of the hydrocarbon and wax. The organo-silicon compounds are selected from the class of organic silicanes and their hydrolysis products and polymers. The silicanes have the formula R/sub y/SiX/sub z/, in which R is a saturated or unsaturated hydrocarbon radical, X is a halogen or another hydrocarbon radical or an -OR group, y has a value 1, 2, or 3 and z has a value 1, 2, or 3.

Process for treating hydrocarbons, etc

Energy Technology Data Exchange (ETDEWEB)

1933-09-15

A process is described for treating simultaneously bituminous substances and hydrocarbon oils for the production of low-boiling hydrocarbons and volatilization of the bituminous substances, characterized by the fact that it consists of heating a current of charge constituted by a mixture of the bituminous substances and hydrocarbon oils, to a high temperature, passing the heated current into a zone of extended reaction where the vapors are separated from the liquid or solid residue to favor transformation of the liquid hydrocarbons and volatilization of the bituminous substances, owing to the utilization of a heating agent carried to a high temperature being brought in contact with the heated charge in order to communicate its heat to the charge, while this later presents itself as relatively fine pellet or in the condition of distinct particles, particularly separated from one another.

Riparian vegetation in the alpine connectome: Terrestrial-aquatic and terrestrial-terrestrial interactions.

Science.gov (United States)

Zaharescu, Dragos G; Palanca-Soler, Antonio; Hooda, Peter S; Tanase, Catalin; Burghelea, Carmen I; Lester, Richard N

2017-12-01

Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment

Polycyclic aromatic hydrocarbons in Northwest Atlantic finfish : available and needed knowledge for monitoring

International Nuclear Information System (INIS)

Hellou, J.; Leonard, J.; Collier, T.K.; Ariese, F.

2004-01-01

This study addressed some of the human health risk factors associated with polycyclic aromatic hydrocarbons (PAHs). These toxic chemicals degrade with time, depending on their source and structure. However, they can also persist long enough and exist at elevated levels to have a possible toxic risk associated with exposure. Most studies on invertebrates have examined bioaccumulation rather than biotransformation. Biotransformation occurs more readily in vertebrates because they have active mixed function oxygenase enzymes. The fate of the oxidation products is of particular interest because they are associated with the formation of DNA-adducts that have carcinogenic effects. Exposed organisms can be monitored for chemical, biochemical or biological endpoints. This study examined PAH concentrations in small finfish such as capelin, sand lance, American plaice, yellowtail flounder and herring collected from the district of the Northwest Atlantic Fisheries Organization. Variables included pool size, size differences within species, lipid content and location. The exposure routes for bioaccumulation were respiration and feeding. The two sources were combustion and fossil fuels. All samples showed signs of alkylated naphthalene which would have been take up by respiration. They were likely derived from petroleum seeps in the water column. Smaller fish had higher concentrations of 3 alkylated naphthalenes. This paper described the relative concentrations in whole fish and internal organs. Measurements carried out prior to development of the Hibernia oil fields revealed baseline levels. Biotransformation products must yet be measured in order to assess future exposure and effects, particularly with long term exposure to waste water. 7 refs., 1 fig

Alkane and polycyclic aromatic hydrocarbons in sediments and benthic invertebrates of the northern Chukchi Sea

Science.gov (United States)

Harvey, H. Rodger; Taylor, Karen A.

2017-10-01

The Hanna Shoal region represents an important northern gateway for transport and deposition in the Chukchi Sea. This study determined the concentration and distribution of organic contaminants (aliphatic hydrocarbon and polycyclic aromatic hydrocarbons, PAHs) in surface sediments from 34 sites across Hanna Shoal. Up to 31 total PAHs, including parent and alkyl homologues were detected with total concentrations ranging from a low of 168 ng g-1 the western flank of Hanna Shoal (station H34) to 1147 ng g-1 at station in Barrow Canyon (station BarC5). Alkyl PAHs were more abundant than parent structures and accounted for 53-64% of the summed concentrations suggesting overall at background levels (< 1600 ng g-1) in sediments. Alkane (C15-C33) hydrocarbons ranged from 4.3 μg g-1 on the southern flank of Hanna shoal to 31 μg g-1 at a northern station. Sediments were often dominated by short chain (C15-C22) alkanes with overall terrestrial aquatic ratios (TAR) for the region averaging 0.20. Based on the ratio of Fl/(Fl+ Py) and BaF/(Baf+BeP) verses (BA/BA+Ch) in sediments, PAHs are largely derived from petrogenic sources with minor amounts of mixed combustion sources. A diversity of PAHs were detected in the northern whelk Neptunea heros foot muscle with total concentrations ranging from 0.14 to 1.5 μg g-1 dry tissue wt. Larger (and presumably older) animals showed higher levels of PAH per unit muscle tissue, suggesting that animals may bioaccumulate PAHs over time, with low but increasing concentrations also present in internal and external eggs. Alkane hydrocarbons were also higher in whelks with distributions similar to that seen in sediments. The mussel Muscularus discors collected in Barrow Canyon showed constrained distributions and substantially lower concentrations of both PAHs and alkanes than the surrounding surface sediments.

Water quality and quantity of selected springs and seeps along the Colorado River corridor, Utah and Arizona: Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Canyon National Park, 1997-98

Science.gov (United States)

Taylor, Howard E.; Spence, John R.; Antweiler, Ronald C.; Berghoff, Kevin; Plowman, Terry I.; Peart, Dale B.; Roth, David A.

2004-01-01

The U.S. Geological Survey, in cooperation with the National Park Service conducted an intensive assessment of selected springs along the Colorado River Corridor in Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Canyon National Park in 1997 and 1998, for the purpose of measuring and evaluating the water quality and quantity of the resource. This study was conducted to establish baseline data for the future evaluation of possible effects from recreational use and climate change. Selected springs and seeps were visited over a study period from 1997 to 1998, during which, discharge and on-site chemical measurements were made at selected springs and seeps, and samples were collected for subsequent chemical laboratory analysis. This interdisciplinary study also includes simultaneous studies of flora and fauna, measured and sampled coincidently at the same sites. Samples collected during this study were transported to U.S. Geological Survey laboratories in Boulder, Colorado, where analyses were performed using state-of-the-art laboratory technology. The location of the selected springs and seeps, elevation, geology, aspect, and onsite measurements including temperature, discharge, dissolved oxygen, pH, and specific conductance, were recorded. Laboratory analyses include determinations for alkalinity, aluminum, ammonium (nitrogen), antimony, arsenic, barium, beryllium, bismuth, boron, bromide, cadmium, calcium, cerium, cesium, chloride, chromium, cobalt, copper, dissolved inorganic carbon, dissolved organic carbon, dysprosium, erbium, europium, fluoride, gadolinium, holmium, iodine, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, mercury, molybdenum, neodymium, nickel, nitrate (nitrogen), nitrite (nitrogen), phosphate, phosphorus, potassium, praseodymium, rhenium, rubidium, samarium, selenium, silica, silver, sodium, strontium, sulfate, tellurium, terbium, thallium, thorium, thulium, tin, titanium, tungsten

Geologic Emissions of Methane and C2 - C5 Alkanes at the La Brea Tar Pits, Los Angeles, CA

Science.gov (United States)

Doezema, L. A.; Etiope, G.; Pacheco, C.

2017-12-01

Natural hydrocarbon (oil and gas) seeps are widespread in Los Angeles due to gas migration, along faults, from numerous subsurface petroleum fields. These seeps may represent important natural contributors of methane (CH4) and heavier alkanes (C2-C4) for the atmosphere. Methane flux measurements were made from various locations at the La Brea Tar Pits in Los Angeles, CA. Measurements were made using a closed-chamber method and spectroscopic sensors for CH4 and CO2, at 26 oil-asphalt seeps and 188 other sites, without gas manifestations, homogeneously distributed throughout the park. The molecular C1 - C5 composition of gas released from seeps and soil was also analyzed using either FTIR spectroscopy or gas chromatography (GC-FID). Methane emissions from seeps varied from approximately 7 to 54,000 g m-2 day-1, while emissions from soil degassing were between 0 and 9,000 g m-2 day-1. Total emissions were estimated to be in the order of 103 kg day-1 for methane, and at least 10 and 5 kg day-1 for ethane and propane, respectively. The seeping gas exhibited high C1/(C2 + C3) ratios, likely due to molecular fractionation during gas migration from a subsurface petroleum reservoir. Evidence for biodegredation in certain samples was indicated by large i-butane to n-butane ratios. These molecular alterations can be important tracers of natural seepage and should be considered in the atmospheric modelling of the relative contribution of fossil fuel (anthropogenic fugitive emission and natural geologic sources) vs biogenic sources, on local and global scales.

Gamma-radiation induced polymerization of methyl methacrylate in aliphatic hydrocarbons: kinetics and evidence for incorporation of hydrocarbon in the polymer chain

International Nuclear Information System (INIS)

Mohan, H.; Iyer, R.M.

1989-01-01

On γ-radiolysis, the rate of polymerization of methyl methacrylate in hydrocarbon solvents is observed to decrease. It is explained by hydrocarbon entry into the polymer chains. The hydrocarbon entry into the polymer chains is observed to take place at later stages of polymerization and increases with hydrocarbon chain length. The extent of hydrocarbon entry into the polymer chains is estimated by NMR and GLC analysis. It is observed to be equal to ∼ 12% corresponding to ∼ 97 hexadecane molecules in each polymer chain. The IR, DSC, MW determination and radiation effects on the polymer showed evidences for hydrocarbon entry into the polymer. It is explained by chain transfer from the growing polymer radical to the hydrocarbon molecules. The chain transfer constant is determined to be equal to 1 x 10 -2 . (author)

Does terrestrial epidemiology apply to marine systems?

Science.gov (United States)

McCallum, Hamish I.; Kuris, Armand M.; Harvell, C. Drew; Lafferty, Kevin D.; Smith, Garriet W.; Porter, James

2004-01-01

Most of epidemiological theory has been developed for terrestrial systems, but the significance of disease in the ocean is now being recognized. However, the extent to which terrestrial epidemiology can be directly transferred to marine systems is uncertain. Many broad types of disease-causing organism occur both on land and in the sea, and it is clear that some emergent disease problems in marine environments are caused by pathogens moving from terrestrial to marine systems. However, marine systems are qualitatively different from terrestrial environments, and these differences affect the application of modelling and management approaches that have been developed for terrestrial systems. Phyla and body plans are more diverse in marine environments and marine organisms have different life histories and probably different disease transmission modes than many of their terrestrial counterparts. Marine populations are typically more open than terrestrial ones, with the potential for long-distance dispersal of larvae. Potentially, this might enable unusually rapid propagation of epidemics in marine systems, and there are several examples of this. Taken together, these differences will require the development of new approaches to modelling and control of infectious disease in the ocean.

Steam hydrocarbon cracking and reforming

NARCIS (Netherlands)

Golombok, M.

2004-01-01

Many industrial chemical processes are taught as distinct contrasting reactions when in fact the unifying comparisons are greater than the contrasts. We examine steam hydrocarbon reforming and steam hydrocarbon cracking as an example of two processes that operate under different chemical reactivity

) Geochemistry and Hydrocarbon Potential of Cretaceous Shales in the Chad Basin

International Nuclear Information System (INIS)

Alalade, B.; Ogunyemi, A. T.; Abimbola, A.F.; Olugbemiro, R. O.

2003-01-01

The Chad Basin is the largest intracratonic basin in Africa and is filled with more than 400m of Cretaceous to Recent sediments. Geochemical and petrographic studies of Cretaceous shales form the Bima, Gongola and Fika Formations were carried out to establish their hydrocarbon potential and thermal maturity. Ditch cuttings of the shales were collected from the Wa di and Karen's exploration wells located in the Nigerian sector of the Chad Basin.The geochemical analysis of the shales indicate that, except for Si02 and K20, all other oxides (Mg O, Fe2O3, AL2O3, CaO) are more abundant in the Fika shale than the Gongola shale. This suggests a more marine condition for the Fika shale compared to the Gongola shale. The Fika and Gongola shales were further classified into Iron shale and shale respectively. Organic carbon contents of the Bima, Gongola and exceed the minimum (0.5wt%) usually required for siliciclastic petroleum source rock. However, the soluble organic matter (SOM) and saturated hydrocarbon (SHC) contents of the shales, which ranges from 108pm to 743ppm and 23ppm to 100ppm respectively, are generally low and are therefore, organically lean. The organic matter of the shales is predominantly terrestrially derived, vitrinite rich, Type III kerogen and are therefore, gas prone. Thermal maturity assessed from SOM/TOC, SHC/TOC ratios and spore color index (SCI) indicate that the Fika shale is immature while the Gongola and Bima shales are within the oil window

Russia and China hydrocarbon relations. A building block toward international hydrocarbon regulation?

International Nuclear Information System (INIS)

Locatelli, Catherine; Abbas, Mehdi; Rossiaud, Sylvain

2015-12-01

This article is a first step of a research agenda on international hydrocarbon regulations. With regards to both: i) the new wealth and power equilibrium in the international political economy and ii) the new political economy of carbon that is emerging from The Paris agreement on Climate changes, this research agenda aims at analysing the changing national structures of governance and the ways these changes lead to international, bilateral, pluri-lateral or multilateral hydrocarbon regulation

Polycyclic hydrocarbon biomarkers confirm selective incorporation of petroleum in soil and kangaroo rat liver samples near an oil well blowout site in the western San Joaquin Valley, California

International Nuclear Information System (INIS)

Kaplan, I.; Lu, S.T.; Lee, R.P.; Warrick, G.

1996-01-01

Following an accidental oil well blow out at an oil field in the western part of the San Joaquin Valley, soil samples and specimens of Heermann's kangaroo rats (Dipodomys heermanni) were collected from two oil-impacted areas and one control area. Fingerprinting by GC-MS and quantitative evaluation of metabolized petroleum hydrocarbons was performed on oil, soil extracts, and rat livers. A liver from a domestically raised rabbit was used as an experimental control. The results show that there is no significant incorporation of PAHs or low molecular weight n-alkanes (C 13 --C 25 ) into the liver tissues. The C 25 --C 35 n-alkane range for all soil samples, kangaroo rat livers, and rabbit liver, is dominated by a high abundance of C 27 , C 29 , C 31 , and C 33 hydrocarbons typical of epicuticular plant waxes. In all liver tissue samples, squalene, the cholesterol precursor, is the dominant hydrocarbon. Although evidence is lacking for metabolism of PAHs and paraffinic petroleum hydrocarbons, very strong evidence is available for incorporation of a set of polycyclic hydrocarbons (biomarkers) belonging to the terpane, sterane, and monoaromatic and triaromatic sterane families, identified by ion monitoring at 191, 217, 253, and 231 m/z, respectively. Because these hydrocarbons are not known to exist in the biosphere, but are only synthesized during oil- and coal-forming processes, their presence in the liver samples constitutes proof for crude oil incorporation into tissues. This conclusion is further substantiated by the selective incorporation of only the 20S enantiomer of C 28 and C 29 steranes and aromatic steranes into the livers, with the exclusion of the 20R enantiomer. The results from the study conclusively demonstrate that polycyclic hydrocarbon biomarkers provide excellent indices for proof of petroleum exposure and metabolism in some terrestrial herbivores

Use of the intestinal parasite community of Sigmodon hispidus as a biomonitor in terrestrial systems

International Nuclear Information System (INIS)

Faulkner, B.C.; Lochmiller, R.L.

1995-01-01

The goal of this study was to assess the potential usefulness of parasite communities of small mammals as an endpoint for community level risk assessment in terrestrial ecosystems. A total of 350 wild cotton rats (Sigmodon hispidus) were collected from a Superfund site in southwestern Oklahoma between fall 1993 and fall 1995. Three contaminated study sites, representing common petrochemical disposal methods and all containing complex mixtures of contaminants, including arsenic, lead, fluoride, phenols, and hydrocarbons, were monitored seasonally. Animals were collected and gastrointestinal contents were examined grossly and microscopically for helminths and coccidial parasites. All parasites were identified to species and enumerated so that measurable alterations of the parasite community structure could be established. The authors also sampled possible intermediate host communities concurrently with Sigmodon collections. Structural characteristics of the parasite communities were compared between replicated toxic and reference study sites

27 CFR 21.125 - Rubber hydrocarbon solvent.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rubber hydrocarbon solvent. 21.125 Section 21.125 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....125 Rubber hydrocarbon solvent. (a) Rubber hydrocarbon solvent is a petroleum derivative. (b...

Collision data involving hydro-carbon molecules

International Nuclear Information System (INIS)

Tawara, H.; Itikawa, Y.; Nishimura, H.; Tanaka, H.; Nakamura, Y.

1990-07-01

Hydro-carbon molecules are abundantly produced when graphites are used as internal wall materials of hydrogen plasmas and strongly influence properties of low temperature plasmas near the edges as well as those of high temperature plasmas at the center. In this report, following simple description of the production mechanisms of hydro-carbon molecules under the interactions between graphite and hydrogen plasma, the present status of collision data for hydro-carbon molecules by electron impact is discussed and the relevant data are summarized in a series of figures and tables. It should also be noted that, in addition to fusion plasmas, these hydrocarbon data compiled here are quite useful in other applications such as plasma chemistry and material processing. (author)

Process for desulfurizing hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1937-04-12

A process is described for the desulfurization of a mixture of hydrocarbons, and in particular hydrocarbons containing less than 7 atoms of carbon and sulfur compounds of the type of sulfur carbonyl, characterized by the fact that the mixture, preferably in the liquid phase, is brought in contact with a solution of caustic alkali, essentially anhydrous or preferably with a solution of alkali hydroxide in an organic hydroxy nonacid solvent, for example, an alcohol, or with an alkaline alcoholate, under conditions suitable to the formation of hydrogen sulfide which produces a hydrocarbon mixture free from sulfur compounds of the sulfur carbonyl type but containing hydrogen sulfide, and that it is treated, following mixing, having beem submitted to the first treatment, by means of aqueous alkaline hydroxide to eliminate the hydrogen sulfide.

Compositional changes of aromatic steroid hydrocarbons in naturally weathered oil residues in the Egyptian western desert

International Nuclear Information System (INIS)

Barakat, A.O.; Qian, Y.; Kim, M.; Kennicutt, M.C. II

2002-01-01

Aromatic steranes are geochemical markers that can be used to study the maturation of organic matter of sediments and to correlate crude oils and source rocks. In this study, naturally weathered oil residues from an arid waste disposal site in Al-Alamein, Egypt, were analyzed for monoaromatic and triaromatic steranes to show the usefulness of biomarker compounds in assessing changes in chemical composition during the degradation of oil residues that have been released onto terrestrial environments. Gas chromatography and mass spectrometry were used to characterize the individual aromatic compounds. Results indicate that triaromatic sterane distributions are similar in oil residues with varying extents of weathering. The distribution correlated with a fresh crude oil sample from Western Desert-sourced oil. Molecular ratios of triaromatic sterane compounds were found to be suitable for source identification. The major changes in chemical compositions resulting from the weathering of the oil included the depletion of short chain mono- and tri-aromatic steranes in extremely weathered samples. The results of the triaromatic sterane distribution correspond with weathering classifications based on the analyses of saturated and aromatic hydrocarbons and the ratios of n-alkanes, polycyclic aromatic hydrocarbons, and saturate biomarker compounds. 15 refs., 3 tabs., 3 figs

Hydrocarbon-degrading bacteria isolation and surfactant influence ...

African Journals Online (AJOL)

Hydrocarbons are substantially insoluble in water, often remaining partitioned in the non-aqueous phase liquid (NAPL). However, there had been little or no attempts to advance the bioavailability of hydrocarbons through the use of surfactants. This study was conducted based on the need to isolate hydrocarbon degrading ...

Sensitivity ranking for freshwater invertebrates towards hydrocarbon contaminants.

Science.gov (United States)

Gerner, Nadine V; Cailleaud, Kevin; Bassères, Anne; Liess, Matthias; Beketov, Mikhail A

2017-11-01

Hydrocarbons have an utmost economical importance but may also cause substantial ecological impacts due to accidents or inadequate transportation and use. Currently, freshwater biomonitoring methods lack an indicator that can unequivocally reflect the impacts caused by hydrocarbons while being independent from effects of other stressors. The aim of the present study was to develop a sensitivity ranking for freshwater invertebrates towards hydrocarbon contaminants, which can be used in hydrocarbon-specific bioindicators. We employed the Relative Sensitivity method and developed the sensitivity ranking S hydrocarbons based on literature ecotoxicological data supplemented with rapid and mesocosm test results. A first validation of the sensitivity ranking based on an earlier field study has been conducted and revealed the S hydrocarbons ranking to be promising for application in sensitivity based indicators. Thus, the first results indicate that the ranking can serve as the core component of future hydrocarbon-specific and sensitivity trait based bioindicators.

High Pressure Preignition Chemistry of Hydrocarbons and Hydrocarbon Mixtures

National Research Council Canada - National Science Library

Cernansky, N.P

1998-01-01

.... The research program entailed mechanistic studies examining the oxidation chemistry of single-component hydrocarbons and ignition studies examining the overall ignition of pure single component fuels and fuel blends...

Terrestrial Steering Group. 2014. Arctic Terrestrial Biodiversity Monitoring Plan

DEFF Research Database (Denmark)

Aastrup, Peter; Aronsson, Mora; Barry, Tom

capacity and information may be currently available and (b) to outline near-term required steps to begin implementing the plan and reporting on an initial set of Arctic terrestrial biodiversity focal ecosystem component attributes. The specific objectives of the workshop were to: Identify key products...... for TSG for the next two years. Identify key components of a pan-Arctic status report for priority focal ecosystem components (FEC) attributes for policy and decision makers. Develop a prioritized set of activities to meet reporting objectives. Identify key milestones and timelines for the successful...... implementation of the Arctic Terrestrial Biodiversity Monitoring Plan for the next two years. Identify expert networks required for successful implementation of the plan. Identify key gaps and opportunities for the TSG related to plan implementation and identify near-term next steps to address gaps....

MODIS-derived terrestrial primary production [chapter 28

Science.gov (United States)

Maosheng Zhao; Steven Running; Faith Ann Heinsch; Ramakrishna Nemani

2011-01-01

Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of...

Process for refining hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Risenfeld, E H

1924-11-26

A process is disclosed for the refining of hydrocarbons or other mixtures through treatment in vapor form with metal catalysts, characterized by such metals being used as catalysts, which are obtained by reduction of the oxide of minerals containing the iron group, and by the vapors of the hydrocarbons, in the presence of the water vapor, being led over these catalysts at temperatures from 200 to 300/sup 0/C.

The Planetary Terrestrial Analogues Library (PTAL)

Science.gov (United States)

Werner, S. C.; Dypvik, H.; Poulet, F.; Rull Perez, F.; Bibring, J.-P.; Bultel, B.; Casanova Roque, C.; Carter, J.; Cousin, A.; Guzman, A.; Hamm, V.; Hellevang, H.; Lantz, C.; Lopez-Reyes, G.; Manrique, J. A.; Maurice, S.; Medina Garcia, J.; Navarro, R.; Negro, J. I.; Neumann, E. R.; Pilorget, C.; Riu, L.; Sætre, C.; Sansano Caramazana, A.; Sanz Arranz, A.; Sobron Grañón, F.; Veneranda, M.; Viennet, J.-C.; PTAL Team

2018-04-01

The Planetary Terrestrial Analogues Library project aims to build and exploit a spectral data base for the characterisation of the mineralogical and geological evolution of terrestrial planets and small solar system bodies.

More than 2500 years of oil exposure shape sediment microbiomes with the potential for syntrophic degradation of hydrocarbons linked to methanogenesis.

Science.gov (United States)

Michas, Antonios; Vestergaard, Gisle; Trautwein, Kathleen; Avramidis, Pavlos; Hatzinikolaou, Dimitris G; Vorgias, Constantinos E; Wilkes, Heinz; Rabus, Ralf; Schloter, Michael; Schöler, Anne

2017-09-11

Natural oil seeps offer the opportunity to study the adaptation of ecosystems and the associated microbiota to long-term oil exposure. In the current study, we investigated a land-to-sea transition ecosystem called "Keri Lake" in Zakynthos Island, Greece. This ecosystem is unique due to asphalt oil springs found at several sites, a phenomenon already reported 2500 years ago. Sediment microbiomes at Keri Lake were studied, and their structure and functional potential were compared to other ecosystems with oil exposure histories of various time periods. Replicate sediment cores (up to 3-m depth) were retrieved from one site exposed to oil as well as a non-exposed control site. Samples from three different depths were subjected to chemical analysis and metagenomic shotgun sequencing. At the oil-exposed site, we observed high amounts of asphalt oil compounds and a depletion of sulfate compared to the non-exposed control site. The numbers of reads assigned to genes involved in the anaerobic degradation of hydrocarbons were similar between the two sites. The numbers of denitrifiers and sulfate reducers were clearly lower in the samples from the oil-exposed site, while a higher abundance of methanogens was detected compared to the non-exposed site. Higher abundances of the genes of methanogenesis were also observed in the metagenomes from other ecosystems with a long history of oil exposure, compared to short-term exposed environments. The analysis of Keri Lake metagenomes revealed that microbiomes in the oil-exposed sediment have a higher potential for methanogenesis over denitrification/sulfate reduction, compared to those in the non-exposed site. Comparison with metagenomes from various oil-impacted environments suggests that syntrophic interactions of hydrocarbon degraders with methanogens are favored in the ecosystems with a long-term presence of oil.

Using Ant Communities For Rapid Assessment Of Terrestrial Ecosystem Health

Energy Technology Data Exchange (ETDEWEB)

Wike, L

2005-06-01

relative health of the ecosystem. The IBI, though originally for Midwestern streams, has been successfully adapted to other ecoregions and taxa (macroinvertebrates, Lombard and Goldstein, 2004) and has become an important tool for scientists and regulatory agencies alike in determining health of stream ecosystems. The IBI is a specific type of a larger group of methods and procedures referred to as Rapid Bioassessment (RBA). These protocols have the advantage of directly measuring the organisms affected by system perturbations, thus providing an integrated evaluation of system health because the organisms themselves integrate all aspects of their environment and its condition. In addition to the IBI, the RBA concept has also been applied to seep wetlands (Paller et al. 2005) and terrestrial systems (O'Connell et al. 1998, Kremen et al. 1993, Rodriguez et al. 1998, Rosenberg et al. 1986). Terrestrial RBA methods have lagged somewhat behind those for aquatic systems because terrestrial systems are less distinctly defined and seem to have a less universal distribution of an all-inclusive taxon, such as fish in the IBI, upon which to base an RBA. In the last decade, primarily in Australia, extensive development of an RBA using ant communities has shown great promise. Ants have the same advantage for terrestrial RBAs that fish do for aquatic systems in that they are an essential and ubiquitous component of virtually all terrestrial ecosystems. They occupy a broad range of niches, functional groups, and trophic levels and they possess one very important characteristic that makes them ideal for RBA because, similar to the fishes, there is a wide range of tolerance to conditions within the larger taxa. Within ant communities there are certain groups, genera, or species that may be very robust and abundant under even the harshest impacts. There are also taxa that are very sensitive to disturbance and change and their presence or absence is also indicative of the local

Biogeochemistry of a submerged groundwater seep ecosystem in Lake Huron near karst region of Alpena, MI

Science.gov (United States)

Kinsman-Costello, L. E.; Dick, G.; Sheik, C.; Burton, G. A.; Sheldon, N. D.

2015-12-01

Submerged groundwater seeps in Lake Huron establish ecosystems with distinctive geochemical conditions. In the Middle Island Sinkhole (MIS), a 23-m deep seep, groundwater seepage establishes low O2 (< 4 mg L-1), high sulfate (6 mM) conditions, in which a purple cyanobacteria-dominated mat thrives. The mat is capable of anoxygenic photosynthesis, oxygenic photosynthesis, and chemosynthesis. Within the top 3 cm of the mat-water interface, hydrogen sulfide concentrations increase to 1-7 mM. Little is known about the structure and function of microbes within organic-rich, high-sulfide sediments beneath the mat. Using pore water and sediment geochemical characterization along with microbial community analysis, we elucidated relationships between microbial community structure and ecosystem function along vertical gradients. In sediment pore waters, biologically reactive solutes (SO42-, NH4+, PO43-, and CH4) displayed steep vertical gradients, reflecting biological and geochemical functioning. In contrast, more conservative ions (Ca+2, Mg+2, Na+, and Cl-), did not change significantly with depth in MIS sediments, indicating groundwater influence in the sediment profile. MIS sediments contained more organic matter than typical Lake Huron sediments, and were generally higher in nutrients, metals, and sulfur (acid volatile sulfide). Using the Illumina MiSeq platform we detected 14,127 unique operational taxonomic units across sediment and surface mat samples. Microbial community composition in the MIS was distinctly different from non-groundwater affected areas at similar depth nearby in Lake Huron (ANOSIM, R= 0.74, p=0.002). MIS sediment communities were more diverse that MIS surface mat communities and changed with depth into sediments. MIS sediment community composition was related to several geochemical variables, including organic matter and multiple indicators of phosphorus availability. Elucidating the structure and function of microbial consortia in MIS, a highly

Chemical fingerprinting of hydrocarbon-contamination in soil

DEFF Research Database (Denmark)

Boll, Esther Sørensen; Nejrup, Jens; Jensen, Julie K.

2015-01-01

Chemical fingerprinting analyses of 29 hydrocarbon-contaminated soils were performed to assess the soil quality and determine the main contaminant sources. The results were compared to an assessment based on concentrations of the 16 priority polycyclic aromatic hydrocarbons pointed out by the U...... and in assessing weathering trends of hydrocarbon contamination in the soils. Multivariate data analysis of sum-normalized concentrations could as a stand-alone tool distinguish between hydrocarbon sources of petrogenic and pyrogenic origin, differentiate within petrogenic sources, and detect weathering trends....... Diagnostic ratios of PACs were not successful for source identification of the heavily weathered hydrocarbon sources in the soils. The fingerprinting of contaminated soils revealed an underestimation of PACs in petrogenic contaminated soils when the assessment was based solely on EPAPAH16. As alkyl...

Terrestrial ecosystems and biodiversity

CSIR Research Space (South Africa)

Davis-Reddy, Claire

2017-10-01

Full Text Available Ecoregions Terrestrial Biomes Protected Areas Climate Risk and Vulnerability: A Handbook for Southern Africa | 75 7.2. Non-climatic drivers of ecosystem change 7.2.1. Land-use change, habitat loss and fragmentation Land-use change and landscape... concentrations of endemic plant and animal species, but these mainly occur in areas that are most threatened by human activity. Diverse terrestrial ecosystems in the region include tropical and sub-tropical forests, deserts, savannas, grasslands, mangroves...

Bioremediation: Technology for treating hydrocarbon-contaminated wastewater

Energy Technology Data Exchange (ETDEWEB)

Towprayoon, S.; Kuntrangwattana, S. [King Mongkut`s Institute of Technology, Bangkok (Thailand)

1996-12-31

Cutting oil wastewater from an iron and steel factory was applied to the soil windrow. Self-remediation was then compared with remediation with acclimatized indigenous microbes. The incremental reduction rate of the microorganisms and hydrocarbon-degradable microbes was slower in self-remediation than in the latter treatment. Within 30 days, when the acclimatized indigenous microbes were used, there was a significant reduction of the contaminated hydrocarbons, while self-remediation took longer to reduce to the same concentration. Various nitrogen sources were applied to the soil pile, namely, organic compost, chemical fertilizer, ammonium sulfate, and urea. The organic compost induced a high yield of hydrocarbon-degradable microorganisms, but the rate at which the cutting oil in the soil decreased was slower than when other nitrogen sources were used. The results of cutting oil degradation studied by gas chromatography showed the absence of some important hydrocarbons. The increment of the hydrocarbon-degradable microbes in the land treatment ecosystem does not necessarily correspond to the hydrocarbon reduction efficiency. 3 refs., 3 figs.

Biodegradation of petroleum hydrocarbons at low temperatures

International Nuclear Information System (INIS)

Whyte, L. G.; Greer, C W.

1999-01-01

Bioremediation of contaminated Arctic sites has been proposed as the logistically and economically most favorable solution despite the known technical difficulties. The difficulties involve the inhibition of pollutants removal by biodegradation below freezing temperatures and the relative slowness of the process to remove enough hydrocarbon pollutants during the above-freezing summer months. Despite these formidable drawbacks, biodegradation of hydrocarbon contaminants is possible even in below-zero temperatures, especially if indigenous psychrophilic and psychrotropic micro-organism are used. This paper reports results of a study involving several hydrocarbon-degrading psychrotropic bacteria and suggests bioaugmentation with specific cold-adapted organisms and/or biostimulation with commercial fertilizers for enhancing degradation of specific contaminants in soils from northern Canada. An evaluation of the biodegradation potential of hydrocarbon contaminated soils in the high Arctic suggested that the contaminated soils contained sufficient numbers of cold-adapted hydrocarbon-degrading bacteria and that the addition of fertilizer was sufficient to enhance the level of hydrocarbon degradation at low ambient summer temperatures. 9 refs., 2 tabs., 3 figs

Preliminary Geospatial Analysis of Arctic Ocean Hydrocarbon Resources

Energy Technology Data Exchange (ETDEWEB)

Long, Philip E.; Wurstner, Signe K.; Sullivan, E. C.; Schaef, Herbert T.; Bradley, Donald J.

2008-10-01

Ice coverage of the Arctic Ocean is predicted to become thinner and to cover less area with time. The combination of more ice-free waters for exploration and navigation, along with increasing demand for hydrocarbons and improvements in technologies for the discovery and exploitation of new hydrocarbon resources have focused attention on the hydrocarbon potential of the Arctic Basin and its margins. The purpose of this document is to 1) summarize results of a review of published hydrocarbon resources in the Arctic, including both conventional oil and gas and methane hydrates and 2) develop a set of digital maps of the hydrocarbon potential of the Arctic Ocean. These maps can be combined with predictions of ice-free areas to enable estimates of the likely regions and sequence of hydrocarbon production development in the Arctic. In this report, conventional oil and gas resources are explicitly linked with potential gas hydrate resources. This has not been attempted previously and is particularly powerful as the likelihood of gas production from marine gas hydrates increases. Available or planned infrastructure, such as pipelines, combined with the geospatial distribution of hydrocarbons is a very strong determinant of the temporal-spatial development of Arctic hydrocarbon resources. Significant unknowns decrease the certainty of predictions for development of hydrocarbon resources. These include: 1) Areas in the Russian Arctic that are poorly mapped, 2) Disputed ownership: primarily the Lomonosov Ridge, 3) Lack of detailed information on gas hydrate distribution, and 4) Technical risk associated with the ability to extract methane gas from gas hydrates. Logistics may control areas of exploration more than hydrocarbon potential. Accessibility, established ownership, and leasing of exploration blocks may trump quality of source rock, reservoir, and size of target. With this in mind, the main areas that are likely to be explored first are the Bering Strait and Chukchi

Process for in-situ biodegradation of hydrocarbon contaminated soil

International Nuclear Information System (INIS)

Ely, D.L.; Heffner, D.A.

1991-01-01

This patent describes an in situ process for biodegrading hydrocarbons by drawing oxygen into an undisturbed hydrocarbon contaminated zone in a fluid permeable soil. It comprises: establishing a borehole extending from the earth's surface through a hydrocarbon contaminated zone having hydrocarbon degrading microbes therein; lining the borehole with a fluid impermeable liner coaxially spaced and sealingly connected to the inside surface of the borehole and extending from the earth's surface to the hydrocarbon-contaminated zone; the liner including a fluid permeable portion extending from the lower end thereof and through at least a portion of the hydrocarbon contaminated zone, fluidly connecting a source of negative pressure to the fluid impermeable line; evacuating gas from the borehole through the fluid permeable portion of the liner at a rate sufficient to draw air from the earth's surface into the hydrocarbon containing zone; and adjusting the flow rate of the evacuated gas so that the amount of hydrocarbon biodegradation therein is within 50% of the maximum hydrocarbon biodegradation rate as detected by the volume of carbon dioxide in the evacuated gas

Utilization of the terrestrial cyanobacteria

Science.gov (United States)

Katoh, Hiroshi; Tomita-Yokotani, Kaori; Furukawa, Jun; Kimura, Shunta; Yokoshima, Mika; Yamaguchi, Yuji; Takenaka, Hiroyuki

The terrestrial, N _{2}-fixing cyanobacterium, Nostoc commune has expected to utilize for agriculture, food and terraforming cause of its extracellular polysaccharide, desiccation tolerance and nitrogen fixation. Previously, the first author indicated that desiccation related genes were analyzed and the suggested that the genes were related to nitrogen fixation and metabolisms. In this report, we suggest possibility of agriculture, using the cyanobacterium. Further, we also found radioactive compounds accumulated N. commune (cyanobacterium) in Fukushima, Japan after nuclear accident. Thus, it is investigated to decontaminate radioactive compounds from the surface soil by the cyanobacterium and showed to accumulate radioactive compounds using the cyanobacterium. We will discuss utilization of terrestrial cyanobacteria under closed environment. Keyword: Desiccation, terrestrial cyanobacteria, bioremediation, agriculture

Assessing impediments to hydrocarbon biodegradation in weathered contaminated soils.

Science.gov (United States)

Adetutu, Eric; Weber, John; Aleer, Sam; Dandie, Catherine E; Aburto-Medina, Arturo; Ball, Andrew S; Juhasz, Albert L

2013-10-15

In this study, impediments to hydrocarbon biodegradation in contaminated soils were assessed using chemical and molecular methodologies. Two long-term hydrocarbon contaminated soils were utilised which were similar in physico-chemical properties but differed in the extent of hydrocarbon (C10-C40) contamination (S1: 16.5 g kg(-1); S2: 68.9 g kg(-1)). Under enhanced natural attenuation (ENA) conditions, hydrocarbon biodegradation was observed in S1 microcosms (26.4% reduction in C10-C40 hydrocarbons), however, ENA was unable to stimulate degradation in S2. Although eubacterial communities (PCR-DGGE analysis) were similar for both soils, the alkB bacterial community was less diverse in S2 presumably due to impacts associated with elevated hydrocarbons. When hydrocarbon bioaccessibility was assessed using HP-β-CD extraction, large residual concentrations remained in the soil following the extraction procedure. However, when linear regression models were used to predict the endpoints of hydrocarbon degradation, there was no significant difference (P>0.05) between HP-β-CD predicted and microcosm measured biodegradation endpoints. This data suggested that the lack of hydrocarbon degradation in S2 resulted primarily from limited hydrocarbon bioavailability. Copyright © 2013 Elsevier B.V. All rights reserved.

Terrestrial and extraterrestrial fullerenes

Energy Technology Data Exchange (ETDEWEB)

Heymann, D.; Jenneskens, L.W.; Jehlicka, J; Koper, C.; Vlietstra, E. [Rice Univ, Houston, TX (United States). Dept. of Earth Science

2003-07-01

This paper reviews reports of occurrences of fullerenes in circumstellar media, interstellar media, meteorites, interplanetary dust particles (IDPs), lunar rocks, hard terrestrial rocks from Shunga (Russia), Sudbury (Canada) and Mitov (Czech Republic), coal, terrestrial sediments from the Cretaceous-Tertiary-Boundary and Pennian-Triassic-Boundary, fulgurite, ink sticks, dinosaur eggs, and a tree char. The occurrences are discussed in the context of known and postulated processes of fullerene formation, including the suggestion that some natural fullerenes might have formed from biological (algal) remains.

Geochemical assessment of light gaseous hydrocarbons in near-surface soils of Kutch-Saurashtra: Implication for hydrocarbon prospects

Science.gov (United States)

Rao, P. Lakshmi Srinivasa; Madhavi, T.; Srinu, D.; Kalpana, M. S.; Patil, D. J.; Dayal, A. M.

2013-02-01

Light hydrocarbons in soil have been used as direct indicators in geochemical hydrocarbon exploration, which remains an unconventional path in the petroleum industry. The occurrence of adsorbed soil gases, methane and heavier homologues were recorded in the near-surface soil samples collected from Kutch-Saurashtra, India. Soil gas alkanes were interpreted to be derived from deep-seated hydrocarbon sources and have migrated to the surface through structural discontinuities. The source of hydrocarbons is assessed to be thermogenic and could have been primarily derived from humic organic matter with partial contribution from sapropelic matter. Gas chromatographic analyses of hydrocarbons desorbed from soil samples through acid extraction technique showed the presence of methane through n-butane and the observed concentrations (in ppb) vary from: methane (C1) from 4-291, ethane (C2) from 0-84, propane (C3) from 0-37, i-butane (iC4) from 0-5 and n-butane (nC4) from 0-4. Carbon isotopes measured for methane and ethane by GC-C-IRMS, range between -42.9‰ to -13.3‰ (Pee Dee Belemnite - PDB) and -21.2‰ to -12.4‰ (PDB), respectively. The increased occurrence of hydrocarbons in the areas near Anjar of Kutch and the area south to Rajkot of Saurashtra signifies the area potential for oil and gas.

In-situ hydrocarbon delineation using laser-induced fluorescence

International Nuclear Information System (INIS)

Taer, A.D.; Hastings, R.W.; Brown, A.Y.; Frend, R.

1996-01-01

An investigation of hydrocarbons in soils was conducted at an active Shell Oil Company petroleum products terminal, located in Carson, California. An investigation approach involving Laser-Induced Fluorescence (LIF) and Cone Penetrometer Testing (CPT) technologies was implemented to provide real-time, in-situ characterization of site stratigraphy, hydrocarbon distribution and importantly, hydrocarbon product differentiation. The area of investigation is located along a property boundary, where a plume of separate phase hydrocarbons has been actively recovered for several years. CPT/LIF technology was selected for the investigation since previous delineation efforts using hydrocarbon fingerprinting methods proved inconclusive. Additionally, the CPT/LIF technology had the potential to provide a cost effective solution to accomplish project objectives. Based on the information obtained during this investigation, it was determined that the plume of separate phase hydrocarbons along the northern property boundary is from a source distinctly different than any identified hydrocarbons known to be from on-site sources. In addition, the plume was determined to not be connected with any other known on-site hydrocarbon plumes. The results of this CPT/LIF investigation were consistent with the known hydrogeologic conditions. This evaluation determined that CPT/LIF technology was very effective in addressing project objectives and resulted in a significant cost savings

Constructed wetlands for treatment of dissolved phase hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Moore, B J; Ross, S D [Komex International, Calgary, AB (Canada); Gibson, D [Calgary Univ., AB (Canada); Hardisty, P E [Komex Clarke Bond, Bristol (United Kingdom)

1999-01-01

The use of constructed wetlands as an alternative to conventional treatment of condensate-contaminated groundwater was studied. In 1997 a pilot scale wetland was constructed and implemented at the Gulf Strachan Gas Processing Plant to determine its ability in treating extracted groundwater contaminated with natural gas condensates. This paper presented the results of hydrocarbon removal efficiency, hydrocarbon removal mechanisms, winter operation, and the effect of hydrocarbons on vegetation health. The inflow water to the wetland contains 15 to 20 mg/L of C[sub 5]-C[sub 10] hydrocarbons, including 50 per cent BTEX compounds. During the summer months, hydrocarbon removal efficiency was 100 per cent, but decreased to 60 and 30 per cent in the spring and late fall, respectively. The hydrocarbons not removed in the wetland were eventually removed along the outflow channel. Temperature was determined to be an important factor in the variable removal rates, particularly when there is no aeration. The main hydrocarbon removal mechanisms appear to be volatilization, biodegradation and dilution. At present, plant uptake is not a factor. 12 refs., 1 tab., 3 figs.

Constructed wetlands for treatment of dissolved phase hydrocarbons

International Nuclear Information System (INIS)

Moore, B.J.; Ross, S.D.; Gibson, D.; Hardisty, P.E.

1999-01-01

The use of constructed wetlands as an alternative to conventional treatment of condensate-contaminated groundwater was studied. In 1997 a pilot scale wetland was constructed and implemented at the Gulf Strachan Gas Processing Plant to determine its ability in treating extracted groundwater contaminated with natural gas condensates. This paper presented the results of hydrocarbon removal efficiency, hydrocarbon removal mechanisms, winter operation, and the effect of hydrocarbons on vegetation health. The inflow water to the wetland contains 15 to 20 mg/L of C 5 -C 10 hydrocarbons, including 50 per cent BTEX compounds. During the summer months, hydrocarbon removal efficiency was 100 per cent, but decreased to 60 and 30 per cent in the spring and late fall, respectively. The hydrocarbons not removed in the wetland were eventually removed along the outflow channel. Temperature was determined to be an important factor in the variable removal rates, particularly when there is no aeration. The main hydrocarbon removal mechanisms appear to be volatilization, biodegradation and dilution. At present, plant uptake is not a factor. 12 refs., 1 tab., 3 figs

Saturated versus unsaturated hydrocarbon interactions with carbon nanostructures

Directory of Open Access Journals (Sweden)

Deivasigamani eUmadevi

2014-09-01

Full Text Available The interactions of various acyclic and cyclic hydrocarbons in both saturated and unsaturated forms with the carbon nanostructures (CNSs have been explored by using density functional theory (DFT calculations. Model systems representing armchair and zigzag carbon nanotubes (CNTs and graphene have been considered to investigate the effect of chirality and curvature of the CNSs towards these interactions. Results of this study reveal contrasting binding nature of the acyclic and cyclic hydrocarbons towards CNSs. While the saturated molecules show stronger binding affinity in acyclic hydrocarbons; the unsaturated molecules exhibit higher binding affinity in cyclic hydrocarbons. In addition, acyclic hydrocarbons exhibit stronger binding affinity towards the CNSs when compared to their corresponding cyclic counterparts. The computed results excellently corroborate the experimental observations. The interaction of hydrocarbons with graphene is more favourable when compared with CNTs. Bader’s theory of atoms in molecules has been invoked to characterize the noncovalent interactions of saturated and unsaturated hydrocarbons. Our results are expected to provide useful insights towards the development of rational strategies for designing complexes with desired noncovalent interaction involving CNSs.

Radiolysis of hydrocarbons in liquid phase (Modern state of problem)

International Nuclear Information System (INIS)

Saraeva, V.V.

1986-01-01

Problems of ionizing radiation effect on hydrocarbons and hydrocarbon systems in a liquid phase are considered. Modern representations on the mechanism of hydrocarbon radiolysis are presented. Electron moderation and ion-electron pair formation, behaviour of charged particles, excited states, radical formation and their reactions are discussed. Behaviour of certain hydrocarbon classes: alkanes, cyclic hydrocarbons, olefines, aromatic hydrocarbons as well as different hydrocarbon mixtures is considered in detail. Radiation-chemical changes in organic coolants and ways of increasing radiation resistance are considered. Polyphenyl compounds are noted to be most perspective here

Parallel Computing for Terrestrial Ecosystem Carbon Modeling

International Nuclear Information System (INIS)

Wang, Dali; Post, Wilfred M.; Ricciuto, Daniel M.; Berry, Michael

2011-01-01

Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO 2 . The influence of terrestrial ecosystems on atmospheric CO 2 can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO 2 concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO 2 uptake and respiratory CO 2 release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change

Production of hydrocarbons of value

Energy Technology Data Exchange (ETDEWEB)

1931-06-16

A process is described for the production of hydrocarbons of great value by treating with heat and pressure carbonaceous materials such as coals, tars, mineral oils, and products of distillation and transformation of these materials, also for the refining with heat and pressure of mixed liquid hydrocarbons by means of hydrogen gas, preferably in the presence of catalysts, consisting in using as the hydrogenating gas that obtained by gasification of combustible solids after partial or complete cleaning at atmospheric or elevated pressures, by means of solid adsorbents, chemical agents or catalysts, or mixtures of these agents, the hydrocarbons being characterized by strong unsaturation, and the presence of oxygen, sulfur compounds, and oxides of nitrogen.

Total Petroleum Hydrocarbons (TPH): ToxFAQs

Science.gov (United States)

... a state: This map displays locations where Total Petroleum Hydrocarbons (TPH) is known to be present. On ... I get more information? ToxFAQs TM for Total Petroleum Hydrocarbons (TPH) ( Hidrocarburos Totales de Petróleo (TPH) ) August ...

The offshore hydrocarbon releases (HCR) database

International Nuclear Information System (INIS)

Bruce, R.A.P.

1995-01-01

Following Cullen Recommendation 39 which states that: ''The regulatory body should be responsible for maintaining a database with regard to hydrocarbon leaks, spills, and ignitions in the Industry and for the benefit of Industry'', HSE Offshore Safety Division (HSE-OSD) has now been operating the Hydrocarbon Releases (HCR) Database for approximately 3 years. This paper deals with the reporting of Offshore Hydrocarbon Releases, the setting up of the HCR Database, the collection of associated equipment population data, and the main features and benefits of the database, including discussion on the latest output information. (author)

Sustainable treatment of hydrocarbon-contaminated industrial land

OpenAIRE

Cunningham, Colin John

2012-01-01

Land contamination by petroleum hydrocarbons is a widespread and global environmental pollution issue from recovery and refining of crude oil and the ubiquitous use of hydrocarbons in industrial processes and applications. Sustainable treatment of hydrocarbon-contaminated industrial land was considered with reference to seven published works on contaminated railway land including the track ballast, crude oil wastes and contaminated refinery soils. A methodology was developed...

Microplastics as an emerging threat to terrestrial ecosystems.

Science.gov (United States)

de Souza Machado, Anderson Abel; Kloas, Werner; Zarfl, Christiane; Hempel, Stefan; Rillig, Matthias C

2018-04-01

Microplastics (plastics plastic litter or from direct environmental emission. Their potential impacts in terrestrial ecosystems remain largely unexplored despite numerous reported effects on marine organisms. Most plastics arriving in the oceans were produced, used, and often disposed on land. Hence, it is within terrestrial systems that microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle-rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant-pollinators. Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems. © 2017 John Wiley & Sons Ltd.

Hydrocarbon toxicity: an analysis of AAPCC TESS data.

Science.gov (United States)

Cobaugh, Daniel J; Seger, Donna L; Krenzelok, Edward P

2007-01-01

Human hydrocarbon exposures have the potential to cause significant morbidity and mortality. To determine which hydrocarbons were associated with the most severe adverse outcomes, human exposure data reported to American poison information centers were analyzed. Outcome data for single-substance, hydrocarbon exposures reported to the American Association of Poison Control Centers Toxic Exposure Surveillance System from 1994 through 2003 were analyzed. Only cases with definitive medical outcomes were included. Analyses were stratified by five age groups: 59 years. Hazard factors were determined by calculating the sum of the major effects and fatalities for each hydrocarbon category and dividing this by the total number of exposures for that category. To normalize the data, the overall rate of major effects and deaths for each age group was assigned hazard factor value of 1. Hydrocarbon categories with a HF of > or = 1.5 were included in the final analyses. Estimated rates of major effect and fatal outcomes (outcomes/1000 people) were also calculated. 318,939 exposures were analyzed. Exposures to benzene, toluene/xylene, halogenated hydrocarbons, kerosene and lamp oil resulted in the highest hazard factor values. These data demonstrate that hydrocarbons that are absorbed systemically and those with low viscosities are associated with higher hazard factors. The risks associated with hydrocarbons often implicated in abuse by older children and adolescents are also confirmed.

Characterizing Terrestrial Exoplanets

Science.gov (United States)

Meadows, V. S.; Lustig-Yaeger, J.; Lincowski, A.; Arney, G. N.; Robinson, T. D.; Schwieterman, E. W.; Deming, L. D.; Tovar, G.

2017-11-01

We will provide an overview of the measurements, techniques, and upcoming missions required to characterize terrestrial planet environments and evolution, and search for signs of habitability and life.

Thermophilic slurry-phase treatment of petroleum hydrocarbon waste sludges

International Nuclear Information System (INIS)

Castaldi, F.J.; Bombaugh, K.J.; McFarland, B.

1995-01-01

Chemoheterotrophic thermophilic bacteria were used to achieve enhanced hydrocarbon degradation during slurry-phase treatment of oily waste sludges from petroleum refinery operations. Aerobic and anaerobic bacterial cultures were examined under thermophilic conditions to assess the effects of mode of metabolism on the potential for petroleum hydrocarbon degradation. The study determined that both aerobic and anaerobic thermophilic bacteria are capable of growth on petroleum hydrocarbons. Thermophilic methanogenesis is feasible during the degradation of hydrocarbons when a strict anaerobic condition is achieved in a slurry bioreactor. Aerobic thermophilic bacteria achieved the largest apparent reduction in chemical oxygen demand, freon extractable oil, total and volatile solid,s and polycyclic aromatic hydrocarbons (PAHs) when treating oily waste sludges. The observed shift with time in the molecular weight distribution of hydrocarbon material was more pronounced under aerobic metabolic conditions than under strict anaerobic conditions. The changes in the hydrocarbon molecular weight distribution, infrared spectra, and PAH concentrations during slurry-phase treatment indicate that the aerobic thermophilic bioslurry achieved a higher degree of hydrocarbon degradation than the anaerobic thermophilic bioslurry during the same time period

Degradation of volatile hydrocarbons from steam-classified solid waste by a mixture of aromatic hydrocarbon-degrading bacteria.

Science.gov (United States)

Leahy, Joseph G; Tracy, Karen D; Eley, Michael H

2003-03-01

Steam classification is a process for treatment of solid waste that allows recovery of volatile organic compounds from the waste via steam condensate and off-gases. A mixed culture of aromatic hydrocarbon-degrading bacteria was used to degrade the contaminants in the condensate, which contained approx. 60 hydrocarbons, of which 38 were degraded within 4 d. Many of the hydrocarbons, including styrene, 1,2,4-trimethylbenzene, naphthalene, ethylbenzene, m-/p-xylene, chloroform, 1,3-dichloropropene, were completely or nearly completely degraded within one day, while trichloroethylene and 1,2,3-trichloropropane were degraded more slowly.

Production of hydrocarbons, especially ethylene

Energy Technology Data Exchange (ETDEWEB)

1952-01-17

The invention has for its object a process for the production of gaseous nonsaturated hydrocarbons, particularly ethylene and aromatic hydrocarbons, by starting with hydrocarbon oils entirely of paraffinic nature or their fractions, which consists in putting the separated products in contact with solid inert material especially with porous nonmetallic inert material or of heavy metals or their alloys, maybe in a finely divided state or in the form, of pieces or chips, at a temperature above 500/sup 0/C, or better between 600 and 700/sup 0/C at a velocity per hour of 0.6 to 3.0, and preferably 0.75 to 1.5 parts per volume of products per each part of space volume of catalyst.

Process of distilling heavy hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1929-12-03

This invention has for its object the distillation of heavy liquid hydrocarbons for the purpose of obtaining lighter hydrocarbons stable and immediately salable for fuels in combustion motors. The process is distinguished by the fact that the heavy hydrocarbon is distilled by means of heating to a temperature in keeping with the nature of the material to be treated up to 350/sup 0/C under pressure or without pressure the distillation being carried out on catalysts containing successively nickel, copper, and iron (3 parts of nickel, 1 part of copper, and 1 part of iron), the vapors produced by this distillation being exposed in turn to the action of catalysts of the same nature and in the same proportion.

Method for upgrading diene-containing hydrocarbon mixtures

Energy Technology Data Exchange (ETDEWEB)

Kidwell, L.E. Jr.; Holcomb, D.E.

1984-05-22

There is disclosed a method for upgrading of hydrocarbon mixtures, so as to reduce their content of gum precursors such as diolefins and pseudo-diolefins, and provide a resulting product mixture suitable for mild hydrogenation, for use as a motor fuel or as a feed stock to an extraction unit. The process comprises obtaining a hydrocarbon mixture containing about 60-90 wt. % of aromatic components, about 3-40 wt. % of dienes and pseudodienes, and monoolefins, and up to about 6 wt. % of relatively unreactive organic compounds, reacting this mixture with elemental sulfur in the approximate weight ratio of about 5-95 wt. % of the hydrocarbon mixture with about 95-5 wt. % of elemental sulfur, the reaction being carried out at a temperature in the range of 100/sup 0/-150/sup 0/ C. for about 10 minutes to 24 hours with good mixing, removing the unreacted materials by distillation and separating a sulfur-hydrocarbon reaction product to provide the upgraded hydrocarbon mixture.

Seawater-cultured Botryococcus braunii for efficient hydrocarbon extraction.

Directory of Open Access Journals (Sweden)

Kenichi Furuhashi

Full Text Available As a potential source of biofuel, the green colonial microalga Botryococcus braunii produces large amounts of hydrocarbons that are accumulated in the extracellular matrix. Generally, pretreatment such as drying or heating of wet algae is needed for sufficient recoveries of hydrocarbons from B. braunii using organic solvents. In this study, the Showa strain of B. braunii was cultured in media derived from the modified Chu13 medium by supplying artificial seawater, natural seawater, or NaCl. After a certain period of culture in the media with an osmotic pressure corresponding to 1/4-seawater, hydrocarbon recovery rates exceeding 90% were obtained by simply mixing intact wet algae with n-hexane without any pretreatments and the results using the present culture conditions indicate the potential for hydrocarbon milking.Seawater was used for efficient hydrocarbon extraction from Botryococcus braunii. The alga was cultured in media prepared with seawater or NaCl. Hydrocarbon recovery rate exceeding 90% was obtained without any pretreatment.

Effect of hydrocarbons on plasma treatment of NOx

Energy Technology Data Exchange (ETDEWEB)

Penetrante, B.M.; Pitz, W.J.; Hsaio, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

1997-12-31

Lean burn gasoline engine exhausts contain a significant amount of hydrocarbons in the form of propene. Diesel engine exhausts contain little gaseous hydrocarbon; however, they contain a significant amount of liquid-phase hydrocarbons (known as the volatile organic fraction) in the particulates. The objective of this paper is to examine the fate of NO{sub x} when an exhaust gas mixture that contains hydrocarbons is subjected to a plasma. The authors will show that the hydrocarbons promote the oxidation of NO to NO{sub 2}, but not the reduction of NO to N{sub 2}. The oxidation of NO to NO{sub 2} is strongly coupled with the hydrocarbon oxidation chemistry. This result suggests that gas-phase reactions in the plasma alone cannot lead to the chemical reduction of NO{sub x}. Any reduction of NO{sub x} to N{sub 2} can only be accomplished through heterogeneous reactions of NO{sub 2} with surfaces or particulates.

Molecular characterization of autochthonous hydrocarbon utilizing ...

African Journals Online (AJOL)

Prof. Ogunji

Materials and Methods ... culturable hydrocarbon utilizing bacteria (HUB) were enumerated by vapour phase ... hydrocarbon utilizing bacterial isolates by boiling method according to ... obtained in this investigation are consistent with past field studies (Kostka et ... Microbial and other related changes in a Niger sediment.

Diversity and distribution of eukaryotic microbes in and around a brine pool adjacent to the Thuwal cold seeps in the Red Sea

KAUST Repository

Wang, Yong

2014-02-04

A hypoxic/suboxic brine pool at a depth of about 850 m was discovered near the Thuwal cold seeps in the Red Sea. Filled with high concentrations of hydrogen sulfide and ammonia, such a brine pool might limit the spread of eukaryotic organisms. Here, we compared the communities of the eukaryotic microbes in a microbial mat, sediments and water samples distributed in 7 sites within and adjacent to the brine pool. Taxonomic classification of the pyrosequenced 18S rRNA amplicon reads showed that fungi highly similar to the species identified along the Arabic coast were almost ubiquitous in the water and sediment samples, supporting their wide distribution in various environments. The microbial mat displayed the highest species diversity and contained grazers and a considerable percentage of unclassified species. Phylogeny-based methods revealed novel lineages representing a majority of the reads from the interface between the sea water and brine pool. Phylogenetic relationships with more reference sequences suggest that the lineages were affiliated with novel Alveolata and Euglenozoa inhabiting the interface where chemosynthetic prokaryotes are highly proliferative due to the strong chemocline and halocline. The brine sediments harbored abundant species highly similar to invertebrate gregarine parasites identified in different oxygen-depleted sediments. Therefore, the present findings support the uniqueness of some microbial eukaryotic groups in this cold seep brine system. 2014 Wang, Zhang, Cao, Shek, Tian, Wong, Batang, Al-suwailem and Qian.

Volatilisation of aromatic hydrocarbons from soil

DEFF Research Database (Denmark)

Lindhardt, B.; Christensen, T.H.

1996-01-01

The non-steady-state fluxes of aromatic hydrocarbons were measured in the laboratory from the surface of soils contaminated with coal tar Four soil samples from a former gasworks site were used for the experiments. The fluxes were quantified for 11 selected compounds, 4 mono- and 7 polycyclic...... aromatic hydrocarbons, for a period of up to 8 or 16 days. The concentrations of the selected compounds in the soils were between 0.2 and 3,100 mu g/g. The study included the experimental determination of the distribution coefficient of the aromatic hydrocarbons between the sorbed phase and the water under...... saturated conditions. The determined distribution coefficients showed that the aromatic hydrocarbons were more strongly sorbed to the total organic carbon including the coal tar pitch - by a factor of 8 to 25 - than expected for natural organic matter. The fluxes were also estimated using an analytical...

Recovery of hydrocarbon oils

Energy Technology Data Exchange (ETDEWEB)

1941-02-10

A process is disclosed for recovery of hydrocarbon oils, especially lubricating oils or diesel oils, through pressure hydrogenation of distillation, extraction of hydrogenation products from coal or coaly materials or from oils such as mineral oils or tars in liquid phase by use in a reaction vessel of fixed-bed catalysts, characterized in that as starting material is employed material which has been freed of asphaltic and resinous material by hydrogenation refining, vacuum-steam distillation, treatment with hydrogen-rich hydrocarbons (hydroforming), or sulfuric acid.

Oils; lubricants; paraffin-wax compositions; hydrocarbon condensation products

Energy Technology Data Exchange (ETDEWEB)

1934-04-04

Petroleum hydrocarbons such as gasoline, kerosene, Diesel fuel oil, lubricating-oil, and paraffin wax, and like hydrocarbons such as are obtainable from shale oil and by the hydrogenation of carbonaceous materials, are improved by addition of products obtained by condensing a cyclic hydrocarbon with a saturated dihalogen derivative of an aliphatic hydrocarbon containing less than five carbon atoms. The addition of the condensation products increases the viscosity of the hydrocarbon oils specified, and is particularly useful in the case of lubricating-oils; addition of the condensation products to paraffin wax increases the transparency and adherent properties of the wax, and is useful in the manufacture of moulded articles such as candles; the products may also be used in solid lubricating-compositions.

Imaging fluid/solid interactions in hydrocarbon reservoir rocks.

Science.gov (United States)

Uwins, P J; Baker, J C; Mackinnon, I D

1993-08-01

The environmental scanning electron microscope (ESEM) has been used to image liquid hydrocarbons in sandstones and oil shales. Additionally, the fluid sensitivity of selected clay minerals in hydrocarbon reservoirs was assessed via three case studies: HCl acid sensitivity of authigenic chlorite in sandstone reservoirs, freshwater sensitivity of authigenic illite/smectite in sandstone reservoirs, and bleach sensitivity of a volcanic reservoir containing abundant secondary chlorite/corrensite. The results showed the suitability of using ESEM for imaging liquid hydrocarbon films in hydrocarbon reservoirs and the importance of simulating in situ fluid-rock interactions for hydrocarbon production programmes. In each case, results of the ESEM studies greatly enhanced prediction of reservoir/borehole reactions and, in some cases, contradicted conventional wisdom regarding the outcome of potential engineering solutions.

Characterizing Methane Emissions at Local Scales with a 20 Year Total Hydrocarbon Time Series, Imaging Spectrometry, and Web Facilitated Analysis

Science.gov (United States)

Bradley, Eliza Swan

Methane is an important greenhouse gas for which uncertainty in local emission strengths necessitates improved source characterizations. Although CH4 plume mapping did not motivate the NASA Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) design and municipal air quality monitoring stations were not intended for studying marine geological seepage, these assets have capabilities that can make them viable for studying concentrated (high flux, highly heterogeneous) CH4 sources, such as the Coal Oil Point (COP) seep field (˜0.015 Tg CH4 yr-1) offshore Santa Barbara, California. Hourly total hydrocarbon (THC) data, spanning 1990 to 2008 from an air pollution station located near COP, were analyzed and showed geologic CH4 emissions as the dominant local source. A band ratio approach was developed and applied to high glint AVIRIS data over COP, resulting in local-scale mapping of natural atmospheric CH4 plumes. A Cluster-Tuned Matched Filter (CTMF) technique was applied to Gulf of Mexico AVIRIS data to detect CH4 venting from offshore platforms. Review of 744 platform-centered CTMF subsets was facilitated through a flexible PHP-based web portal. This dissertation demonstrates the value of investigating municipal air quality data and imaging spectrometry for gathering insight into concentrated methane source emissions and highlights how flexible web-based solutions can help facilitate remote sensing research.

A method of refining aromatic hydrocarbons from coal chemical production

Energy Technology Data Exchange (ETDEWEB)

Zieborak, K.; Koprowski, A.; Ratajczak, W.

1979-10-01

A method is disclosed for refining aromatic hydrocarbons of coal chemical production by contact of liquid aromatic hydrocarbons and their mixtures with a strongly acid macroporous sulfocationite in the H-form at atmospheric pressure and high temperature. The method is distinguished in that the aromatic hydrocarbons and their mixtures, from which alkali compounds have already been removed, are supplied for refinement with the sulfocationite with simultaneous addition of olefin derivatives of aromatic hydrocarbons, followed by separation of pure hydrocarbons by rectification. Styrene or alpha-methylstyrene is used as the olefin derivatives of the aromatic hydrocarbons. The method is performed in several stages with addition of olefin derivatives of aromatic hydrocarbons at each stage.

Process for recovery of liquid hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Millar, J.F.; Cockshott, J.E.

1978-04-11

Methane is recovered as a gas for discharge to a pipeline from a gas stream containing methane and heavier hydrocarbons, principally ethane and propane. Separation is accomplished by condensing the heavier hydrocarbons and distilling the methane therefrom. A liquid product (LPG) comprising the heavier hydrocarbons is subsequently recovered and transferred to storage. Prior to being discharged to a pipeline, the recovered methane gas is compressed and in undergoing compression the gas is heated. The heat content of the gas is employed to reboil the refrigerant in an absorption refrigeration unit. The refrigeration unit is used to cool the LPG prior to its storage.

Worldwide overview of hydrocarbons and perspectives

International Nuclear Information System (INIS)

Tonnac, Alain de; Perves, Jean-Pierre

2013-12-01

This publication presents and comments data regarding the share of hydrocarbons in the world energy consumption, hydrocarbon trade flows, the new situation created by the emergence of shale hydrocarbons and the consequences for the world economy, and possible risks. The authors first comment the evolution of energy consumption and outline that the objectives of CO 2 and greenhouse gas emission will not be reached (these emissions increased in 2012 and in 2013). They indicate the emission situation in the USA and Japan, and notice that the objectives defined by the IEA are quite different from those defined by the EU. They analyse the evolutions by distinguishing different periods: 2005-2008 as a reference period, 2008-2012 as a period of change, and the current period as a period of flow inversion. Then, the authors propose two different scenarios of evolution of economic and energy policies. The evolution of hydrocarbon demand is commented, and the levels of reserves (oil, conventional gas, coal, nuclear fuels) are discussed. The market evolution is also discussed, not only from an economic point of view, but also in relationship with geopolitics. The authors notably outline that the energy price is different from one country to the other, discuss the issue of hydrocarbon refining, the role of CO 2 tax

Hydrocarbon-degradation by Isolate Pseudomonas lundensis UTAR FPE2

Directory of Open Access Journals (Sweden)

Adeline, S. Y. Ting

2009-01-01

Full Text Available In this study, the potential of isolate Pseudomonas lundensis UTAR FPE2 as a hydrocarbon degrader was established. Their biodegradation activity was first detected with the formation of clearing zones on Bushnell-Hass agar plates, with the largest diameter observed on plates supplemented with paraffin, followed by mineral oil and petrol. Utilization of hydrocarbon sources were again detected in broth cultures supplemented with similar hydrocarbon substrates, where the mean viable cell count recovered from hydrocarbon-supplemented broth cultures were higher than the initial inoculum except for napthalene. In both tests, the isolate showed higher degradability towards aliphatic hydrocarbon sources, and the least activity towards the aromatic hydrocarbon naphthalene. The isolate P. lundensis UTAR FPE2 (8 log10 cfu/mL also degraded crude diesel sample, with 69% degradation during the first three days. To conclude, this study suggests the potential use of this isolate for bioremediation of hydrocarbon-contaminated environments.

Commercialization of terrestrial applications of aerospace power technology

International Nuclear Information System (INIS)

Landsberg, D.R.

1992-01-01

The potential for commercialization of terrestrial energy systems based upon aerospace power technology's explored. Threats to the aerospace power technology industry, caused by the end of the cold war and weak world economy are described. There are also new opportunities caused by increasing terrestrial energy needs and world-wide concern for the environment. In this paper, the strengths and weaknesses of the aerospace power industry in commercializing terrestrial energy technologies are reviewed. Finally, actions which will enable the aerospace power technology industry to commercialize products into terrestrial energy markets are described

Bioassay of polycyclic aromatic hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Van Kirk, E.A.

1980-08-01

A positive relationship was found between the photodynamic activity of 24 polycyclic aromatic hydrocarbons versus published results on the mutagenicity, carcinogenicity, and initiation of unscheduled DNA synthesis. Metabolic activation of benzo(a)pyrene resulted in detection of increased mutagenesis in Paramecium tetraurelia as found also in the Ames Salmonella assay. The utility of P. tetraurelia as a biological detector of hazardous polycyclic aromatic hydrocarbons is discussed.

Terrestrial carbohydrates support freshwater zooplankton during phytoplankton deficiency.

Science.gov (United States)

Taipale, Sami J; Galloway, Aaron W E; Aalto, Sanni L; Kahilainen, Kimmo K; Strandberg, Ursula; Kankaala, Paula

2016-08-11

Freshwater food webs can be partly supported by terrestrial primary production, often deriving from plant litter of surrounding catchment vegetation. Although consisting mainly of poorly bioavailable lignin, with low protein and lipid content, the carbohydrates from fallen tree leaves and shoreline vegetation may be utilized by aquatic consumers. Here we show that during phytoplankton deficiency, zooplankton (Daphnia magna) can benefit from terrestrial particulate organic matter by using terrestrial-origin carbohydrates for energy and sparing essential fatty acids and amino acids for somatic growth and reproduction. Assimilated terrestrial-origin fatty acids from shoreline reed particles exceeded available diet, indicating that Daphnia may convert a part of their dietary carbohydrates to saturated fatty acids. This conversion was not observed with birch leaf diets, which had lower carbohydrate content. Subsequent analysis of 21 boreal and subarctic lakes showed that diet of herbivorous zooplankton is mainly based on high-quality phytoplankton rich in essential polyunsaturated fatty acids. The proportion of low-quality diets (bacteria and terrestrial particulate organic matter) was <28% of the assimilated carbon. Taken collectively, the incorporation of terrestrial carbon into zooplankton was not directly related to the concentration of terrestrial organic matter in experiments or lakes, but rather to the low availability of phytoplankton.

Louisiana ESI: T_MAMMAL (Terrestrial Mammal Polygons)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for terrestrial mammals in Louisiana. Vector polygons in this data set represent terrestrial mammal...

Potential hydrocarbon producing species of Western Ghats, Tamil Nadu, India

Energy Technology Data Exchange (ETDEWEB)

Augustus, G.D.P.S.; Jayabalan, M.; Rajarathinam, K. [Research Centre in Bombay, V.H.N.S.N. College, Virudhunagar (India); Ray, A.K. [Sardar Patel Univ., Anand (India). Dept. of Chemistry; Seiler, G.J. [USDA, ARS, Northern Crop Science Lab., Fargo, ND (United States)

2002-09-01

The decline in the world supplies of hydrocarbons has led to the search for alternate sources of fuel and chemicals. Plant species are potential sources of hydrocarbons. Large-scale screening of plants growing in the Western Ghats, Tamil Nadu, India was conducted to assess the hydrocarbon production and the type of isoprene compound(s) present. Three species contained more than 3% hydrocarbon. Sarcostemma brevistigma had the highest concentration of hydrocarbon with 3.6%. Seven species contained more than 2% of hydrocarbons among the plant species screened. The hydrocarbon fraction of Ficus elastica (leaf) had a gross heat value of 9834 cal/g (41.17 MJ/kg), which is close to the caloric value of fuel oil. Six hydrocarbon fractions contained gross heat values of more than 9000 cal/g (37.68 MJ/kg). Of the 13 species hydrocarbon fraction analysed, seven species contained cis-polyisoprene compounds, while two species contained trans-polyisoprenes. Cis and trans polyisoprenes are potential alternative energy sources for fuel and/or as industrial raw materials. (author)

AD1995: NW Europe's hydrocarbon industry

International Nuclear Information System (INIS)

Glennie, K.; Hurst, A.

1996-01-01

This volume concerns itself with wide-ranging aspects of the upstream hydro-carbon industry over the whole of NW Europe. As such, the book contrasts with many thematic volumes by presenting a broad range of topics side-by-side. One section of the book looks back at the history of geological exploration and production, and provides an overview of hydrocarbon exploration across NW Europe. Another section covers the state of the art in hydrocarbon exploration and production. This includes an update on computer-based basin modelling overpressure systems, innovations in reservoir engineering and reserve estimation, 3D seismic and the geochemical aspects of secondary migration. The final section of the book takes a look into the future. This covers the remaining hydrocarbon resources of the North Sea, managing risk in oil field development, oil field economics, and pollution and the environment. It is the editors' hope that several key areas of NW Europe's upstream oil industry have been usefully summarized in the volume. (Author)

Enrichment of light hydrocarbon mixture

Science.gov (United States)

Yang,; Dali, [Los Alamos, NM; Devlin, David [Santa Fe, NM; Barbero, Robert S [Santa Cruz, NM; Carrera, Martin E [Naperville, IL; Colling, Craig W [Warrenville, IL

2010-08-10

Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

Purifying hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Dunstan, A E

1918-06-03

Ligroin, kerosene, and other distillates from petroleum and shale oil, are purified by treatment with a solution of a hypochlorite containing an excess of alkali. The hydrocarbon may be poured into brine, the mixture stirred, and an electric current passed through. Heat may be applied.

Monitoring of Hydrocarbons in Sediment and Biota Related to Oil and Gas Development in Near- and Off-Shore Areas of the Arctic Beaufort Sea, Alaska

Science.gov (United States)

Durell, G.; Hardin, J.; Libby, S.

2016-02-01

were identified; rivers deliver about 80% of the annual suspended solids to Beaufort Sea within a 2-3 week period each spring with significant input of hydrocarbons from terrestrial sources. The ANIMIDA project has provided monitoring information that can confidently be used for future environmental management.

Specific recognition of reproductive parasite workers by nest-entrance guards in the bumble bee Bombus terrestris.

Science.gov (United States)

Blacher, Pierre; Boreggio, Laurie; Leroy, Chloé; Devienne, Paul; Châline, Nicolas; Chameron, Stéphane

2013-12-10

The impact of social parasites on their hosts' fitness is a strong selective pressure that can lead to the evolution of adapted defence strategies. Guarding the nest to prevent the intrusion of parasites is a widespread response of host species. If absolute rejection of strangers provides the best protection against parasites, more fine-tuned strategies can prove more adaptive. Guarding is indeed costly and not all strangers constitute a real threat. That is particularly true for worker reproductive parasitism in social insects since only a fraction of non-nestmate visitors, the fertile ones, can readily engage in parasitic reproduction. Guards should thus be more restrictive towards fertile than sterile non-nestmate workers. We here tested this hypothesis by examining the reaction of nest-entrance guards towards nestmate and non-nestmate workers with varying fertility levels in the bumble bee Bombus terrestris. Because social recognition in social insects mainly relies on cuticular lipids (CLs), chemical analysis was also conducted to examine whether workers' CLs could convey the relevant information upon which guards could base their decision. We thus aimed to determine whether an adapted defensive strategy to worker reproductive parasitism has evolved in B. terrestris colonies. Chemical analysis revealed that the cuticular chemical profiles of workers encode information about both their colony membership and their current fertility, therefore providing potential recognition cues for a suitable adjustment of the guards' defensive decisions. We found that guards were similarly tolerant towards sterile non-nestmate workers than towards nestmate workers. However, as predicted, guards responded more aggressively towards fertile non-nestmates. Our results show that B. terrestris guards discriminate non-nestmates that differ in their reproductive potential and respond more strongly to the individuals that are a greatest threat for the colony. Cuticular hydrocarbons are

Linking animals aloft with the terrestrial landscape

Science.gov (United States)

Buler, Jeffrey J.; Barrow, Wylie; Boone, Matthew; Dawson, Deanna K.; Diehl, Robert H.; Moore, Frank R.; Randall, Lori A.; Schreckengost, Timothy; Smolinsky, Jaclyn A.

2018-01-01

Despite using the aerosphere for many facets of their life, most flying animals (i.e., birds, bats, some insects) are still bound to terrestrial habitats for resting, feeding, and reproduction. Comprehensive broad-scale observations by weather surveillance radars of animals as they leave terrestrial habitats for migration or feeding flights can be used to map their terrestrial distributions either as point locations (e.g., communal roosts) or as continuous surface layers (e.g., animal densities in habitats across a landscape). We discuss some of the technical challenges to reducing measurement biases related to how radars sample the aerosphere and the flight behavior of animals. We highlight a recently developed methodological approach that precisely and quantitatively links the horizontal spatial structure of birds aloft to their terrestrial distributions and provides novel insights into avian ecology and conservation across broad landscapes. Specifically, we present case studies that (1) elucidate how migrating birds contend with crossing ecological barriers and extreme weather events, (2) identify important stopover areas and habitat use patterns of birds along their migration routes, and (3) assess waterfowl response to wetland habitat management and restoration. These studies aid our understanding of how anthropogenic modification of the terrestrial landscape (e.g., urbanization, habitat management), natural geographic features, and weather (e.g., hurricanes) can affect the terrestrial distributions of flying animals.

Culture-dependent characterization of hydrocarbon utilizing bacteria ...

African Journals Online (AJOL)

EARNEST

Hydrocarbons interact with the environment and micro- organisms determining the .... it is pertinent to study the community dynamics of hydrocarbon degrading bacteria ... Chikere CB (2013). Application of molecular microbiology techniques in.

Identifying future directions for subsurface hydrocarbon migration research

Science.gov (United States)

Leifer, I.; Clark, J. F.; Luyendyk, B.; Valentine, D.

Subsurface hydrocarbon migration is important for understanding the input and impacts of natural hydrocarbon seepage on the environment. Great uncertainties remain in most aspects of hydrocarbon migration, including some basic mechanisms of this four-phase flow of tar, oil, water, and gas through the complex fracture-network geometry particularly since the phases span a wide range of properties. Academic, government, and industry representatives recently attended a workshop to identify the areas of greatest need for future research in shallow hydrocarbon migration.Novel approaches such as studying temporal and spatial seepage variations and analogous geofluid systems (e.g., geysers and trickle beds) allow deductions of subsurface processes and structures that remain largely unclear. Unique complexities exist in hydrocarbon migration due to its multiphase flow and complex geometry, including in-situ biological weathering. Furthermore, many aspects of the role of hydrocarbons (positive and negative) in the environment are poorly understood, including how they enter the food chain (respiration, consumption, etc.) and “percolate” to higher trophic levels. But understanding these ecological impacts requires knowledge of the emissions' temporal and spatial variability and trajectories.

Tropical CO2 seeps reveal the impact of ocean acidification on coral reef invertebrate recruitment.

Science.gov (United States)

Allen, Ro; Foggo, Andrew; Fabricius, Katharina; Balistreri, Annalisa; Hall-Spencer, Jason M

2017-11-30

Rising atmospheric CO 2 concentrations are causing ocean acidification by reducing seawater pH and carbonate saturation levels. Laboratory studies have demonstrated that many larval and juvenile marine invertebrates are vulnerable to these changes in surface ocean chemistry, but challenges remain in predicting effects at community and ecosystem levels. We investigated the effect of ocean acidification on invertebrate recruitment at two coral reef CO 2 seeps in Papua New Guinea. Invertebrate communities differed significantly between 'reference' (median pH7.97, 8.00), 'high CO 2 ' (median pH7.77, 7.79), and 'extreme CO 2 ' (median pH7.32, 7.68) conditions at each reef. There were also significant reductions in calcifying taxa, copepods and amphipods as CO 2 levels increased. The observed shifts in recruitment were comparable to those previously described in the Mediterranean, revealing an ecological mechanism by which shallow coastal systems are affected by near-future levels of ocean acidification. Copyright © 2016 Elsevier Ltd. All rights reserved.

33 CFR 157.166 - Hydrocarbon emissions.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Hydrocarbon emissions. 157.166 Section 157.166 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Crude Oil Washing (COW) System on Tank Vessels Cow Operations § 157.166 Hydrocarbon emissions. If the...

A SIMS Study of Sulfur Isotopes of Accessory Pyrites Associated with Barites from Methane Cold Seeps in the Gulf of Mexico

Science.gov (United States)

Morelli, E. C.; Aharon, P.

2017-12-01

Bacteria and archaea associated with seeps can fix methane from sublimating gas hydrates through coupled bacterial sulfate reduction/ anaerobic methane oxidation (BSR/AMO) and prevent outgassing to the atmosphere. The occurrence of such microbial processes has been established on the basis of the sulfur isotope compositions of microbial byproducts (pyrites; FeS2) that reflect the degree of fractionation between SO4 and FeS2 via the production of the H2S intermediate phase. BSR/AMO coupling has been discerned in accessory sulfides associated with carbonates from gas hydrate sites. Whether BSR/AMO coupling is also active in barites, another ubiquitous product of gas hydrate sublimation, has so far been overlooked. Here we present results of a new sulfur isotope study of accessory sulfides in barites associated with gas hydrates at the threshold of stability occurring on the Gulf of Mexico slope. Using a fractionation factor of 1.009 and a seawater δ34SSO4 value of 20.3‰ and assuming a Rayleigh distillation closed system model for marine sulfide precipitation, pyrites from barite gas seeps are predicted to exhibit a range of δ34S values (about -1‰ to 20‰ CDT) as the pool of sulfate is continuously depleted. Actual δ34S values could fall outside of the predicted range because the system in question is likely only partially closed and kinetic fractionations are likely. δ34S of accessory pyrites from three Garden Banks Lease Block 382 (510 - 640m water depth) and one Mississippi Canyon Lease Block 929 (590m) barite samples have been determined using an ims-1290 Secondary Ion Mass Spectrometer (SIMS). Two Garden Banks samples and one Mississippi Canyon sample reveal a spread of values from 5.30 ± 0.04 to 25.90 ± 0.09 (‰ CDT), which follow the predicted trend for gas seeps and indicate the source of fractionation is likely from the coupled BSR/AMO process. One Garden Banks sample yields a wide spread of values from -26.2 ± 0.05 to 20.5 ± 0.4 (‰ CDT). The

The decadal state of the terrestrial carbon cycle : Global retrievals of terrestrial carbon allocation, pools, and residence times

NARCIS (Netherlands)

Bloom, A Anthony; Exbrayat, Jean-François; van der Velde, Ivar R; Feng, Liang; Williams, Mathew

2016-01-01

The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

Hydrocarbon removal with constructed wetlands

OpenAIRE

Eke, Paul Emeka

2008-01-01

Wetlands have long played a significant role as natural purification systems, and have been effectively used to treat domestic, agricultural and industrial wastewater. However, very little is known about the biochemical processes involved, and the use of constructed treatment wetlands in the removal of petroleum aromatic hydrocarbons from produced and/or processed water. Wastewaters from the oil industry contain aromatic hydrocarbons such as benzene, toluene, ethylbenzene and x...

Performance estimation of ejector cycles using heavier hydrocarbon refrigerants

International Nuclear Information System (INIS)

Kasperski, Jacek; Gil, Bartosz

2014-01-01

Computer software basing on theoretical model of Huang et al. with thermodynamic properties of hydrocarbons was prepared. Investigation was focused on nine hydrocarbons: propane, butane, iso-butane, pentane, iso-pentane, hexane, heptane and octane. A series of calculations was carried out for the generator temperature between 70 and 200 °C, with assumed temperatures of evaporation 10 °C and condensation 40 °C. Calculation results show that none of the hydrocarbons enables high efficiency of a cycle in a wide range of temperature. Each hydrocarbon has its own maximal entrainment ratio at its individual temperature of optimum. Temperatures of entrainment ratios optimum increase according to the hydrocarbon heaviness with simultaneous increase of entrainment ratio peak values. Peak values of the COP do not increase according to the hydrocarbons heaviness. The highest COP = 0.32 is achieved for iso-butane at 102 °C and the COP = 0.28 for pentane at 165 °C. Heptane and octane can be ignored. - Highlights: • Advantages of use of higher hydrocarbons as ejector refrigerants were presumed. • Computer software basing on theoretical model of Huang et al. (1999) was prepared. • Optimal temperature range of vapor generation for each hydrocarbon was calculated

Polycyclic’ Aromatic Hydrocarbon Induced Intracellular Signaling and Lymphocyte Apoptosis

DEFF Research Database (Denmark)

Schneider, Alexander M.

The aryl hydrocarbon (dioxin) receptor (AhR) is a transcription factor possessing high affinity to potent environmental pollutants, polycyclic aromatic hydrocarbons (PAH) and related halogenated hydrocarbons (e.g. dioxins). Numerous research attribute toxicity of these compounds to the receptor...

Method for production of unsaturated gaseous hydrocarbons, particularly ethylene, and of aromatic hydrocarbons, adapted as motor fuels

Energy Technology Data Exchange (ETDEWEB)

1952-10-24

A method is described for the production of unsaturated gaseous hydrocarbons, in particular of ethylene, and of aromatic hydrocarbons from hydrocarbon oils or from fractions of the same, characterized by the fact that the raw materials are brought into contact with porous, inert substances in the form of fine distribution or of pieces at a temperature of above 500 and in particular from 600 to about 700/sup 0/C and with a traversing speed of from 0.3 up to about 3.0 volumetric parts, preferably up to 1.5 volumetric parts of raw material per volumetric part of the chamber and per hour.

Catalytic conversion of alcohols to hydrocarbons with low benzene content

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2016-03-08

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

Catalytic conversion of alcohols to hydrocarbons with low benzene content

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2016-09-06

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

Sex ratio variation in the bumblebee Bombus terrestris

DEFF Research Database (Denmark)

Duchateau, Marie José; Velthuis, Hayo H. W.; Boomsma, Jacobus Jan

2004-01-01

Bombus terrestris, bumblebees, colony development, queen control, reproductive strategies, sex allocation......Bombus terrestris, bumblebees, colony development, queen control, reproductive strategies, sex allocation...

Methods for reformation of gaseous hydrocarbons using electrical discharge

KAUST Repository

Cha, Min Suk

2017-02-16

Methods for the reformation of gaseous hydrocarbons are provided. The methods can include forming a bubble containing the gaseous hydrocarbon in a liquid. The bubble can be generated to pass in a gap between a pair of electrodes, whereby an electrical discharge is generated in the bubble at the gap between the electrodes. The electrodes can be a metal or metal alloy with a high melting point so they can sustain high voltages of up to about 200 kilovolts. The gaseous hydrocarbon can be combined with an additive gas such as molecular oxygen or carbon dioxide. The reformation of the gaseous hydrocarbon can produce mixtures containing one or more of H2, CO, H2O, CO2, and a lower hydrocarbon such as ethane or ethylene. The reformation of the gaseous hydrocarbon can produce low amounts of CO2 and H2O, e.g. about 15 mol-% or less.

Methods for reformation of gaseous hydrocarbons using electrical discharge

KAUST Repository

Cha, Min; Zhang, Xuming

2017-01-01

Methods for the reformation of gaseous hydrocarbons are provided. The methods can include forming a bubble containing the gaseous hydrocarbon in a liquid. The bubble can be generated to pass in a gap between a pair of electrodes, whereby an electrical discharge is generated in the bubble at the gap between the electrodes. The electrodes can be a metal or metal alloy with a high melting point so they can sustain high voltages of up to about 200 kilovolts. The gaseous hydrocarbon can be combined with an additive gas such as molecular oxygen or carbon dioxide. The reformation of the gaseous hydrocarbon can produce mixtures containing one or more of H2, CO, H2O, CO2, and a lower hydrocarbon such as ethane or ethylene. The reformation of the gaseous hydrocarbon can produce low amounts of CO2 and H2O, e.g. about 15 mol-% or less.

The importance of methane and thiosulfate in the metabolism of the bacterial symbionts of two deep-sea mussels

Science.gov (United States)

Fisher, C.R.; Childress, J.J.; Oremland, R.S.; Bidigare, R.R.

1987-01-01

Undescribed hydrocarbon-seep mussels were collected from the Louisiana Slope, Gulf of Mexico, during March 1986, and the ultrastructure of their gills was examined and compared to Bathymodiolus thermophilus, a mussel collected from the deep-sea hydrothermal vents on the Gala??pagos Rift in March 1985. These closely related mytilids both contain abundant symbiotic bacteria in their gills. However, the bacteria from the two species are distinctly different in both morphology and biochemistry, and are housed differently within the gills of the two mussels. The symbionts from the seep mussel are larger than the symbionts from B. thermophilus and, unlike the latter, contain stacked intracytoplasmic membranes. In the seep mussel three or fewer symbionts appear to be contained in each host-cell vacuole, while in B. thermophilus there are often more than twenty bacteria visible in a single section through a vacuole. The methanotrophic nature of the seep-mussel symbionts was confirmed in 14C-methane uptake experiments by the appearance of label in both CO2 and acid-stable, non-volatile, organic compounds after a 3 h incubation of isolated gill tissue. Furthermore, methane consumption was correlated with methanol dehydrogenase activity in isolated gill tissue. Activity of ribulose-1,5-biphosphate (RuBP) carboxylase and 14CO2 assimilation studies indicate the presence of either a second type of symbiont or contaminating bacteria on the gills of freshly captured seep mussels. A reevaluation of the nutrition of the symbionts in B. thermophilus indicates that while the major symbiont is not a methanotroph, its status as a sulfur-oxidizing chemoautotroph, as has been suggested previously, is far from proven. ?? 1987 Springer-Verlag.

Bioremediation of Petroleum Hydrocarbon Contaminated Sites

Energy Technology Data Exchange (ETDEWEB)

Fallgren, Paul

2009-03-30

Bioremediation has been widely applied in the restoration of petroleum hydrocarbon-contaminated. Parameters that may affect the rate and efficiency of biodegradation include temperature, moisture, salinity, nutrient availability, microbial species, and type and concentration of contaminants. Other factors can also affect the success of the bioremediation treatment of contaminants, such as climatic conditions, soil type, soil permeability, contaminant distribution and concentration, and drainage. Western Research Institute in conjunction with TechLink Environmental, Inc. and the U.S. Department of Energy conducted laboratory studies to evaluate major parameters that contribute to the bioremediation of petroleum-contaminated drill cuttings using land farming and to develop a biotreatment cell to expedite biodegradation of hydrocarbons. Physical characteristics such as soil texture, hydraulic conductivity, and water retention were determined for the petroleum hydrocarbon contaminated soil. Soil texture was determined to be loamy sand to sand, and high hydraulic conductivity and low water retention was observed. Temperature appeared to have the greatest influence on biodegradation rates where high temperatures (>50 C) favored biodegradation. High nitrogen content in the form of ammonium enhanced biodegradation as well did the presence of water near field water holding capacity. Urea was not a good source of nitrogen and has detrimental effects for bioremediation for this site soil. Artificial sea water had little effect on biodegradation rates, but biodegradation rates decreased after increasing the concentrations of salts. Biotreatment cell (biocell) tests demonstrated hydrocarbon biodegradation can be enhanced substantially when utilizing a leachate recirculation design where a 72% reduction of hydrocarbon concentration was observed with a 72-h period at a treatment temperature of 50 C. Overall, this study demonstrates the investigation of the effects of

The Circumpolar Biodiversity Monitoring Program Terrestrial Plan

DEFF Research Database (Denmark)

Christensen, Tom; Payne, J.; Doyle, M.

, understand and report on long-term change in Arctic terrestrial ecosystems and biodiversity, and to identify knowledge gaps and priorities. This poster will outline the key management questions the plan aims to address and the proposed nested, multi-scaled approach linking targeted, research based monitoring...... and coastal environments. The CBMP Terrestrial Plan is a framework to focus and coordinate monitoring of terrestrial biodiversity across the Arctic. The goal of the plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect...

Terrestrial nitrogen-carbon cycle interactions at the global scale.

Science.gov (United States)

Zaehle, S

2013-07-05

Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen-carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001-2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr(-1) (1.9 Pg C yr(-1)), of which 10 Tg N yr(-1) (0.2 Pg C yr(-1)) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen-carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr(-1) per 1°C degree climate warming) will add an important long-term climate forcing.

Degradation of petroleum hydrocarbons in a laboratory aquifer column

International Nuclear Information System (INIS)

Billowits, M.; Whyte, L.; Greer, C.; Ramsay, J.

1998-01-01

One of the primary mechanisms for eliminating hydrocarbon pollutants from the environment is degradation of hydrocarbons by indigenous microorganisms. This report describes a study in which samples from a petroleum polluted shallow aquifer in the Yukon were used which contained a hundred times greater concentration of psychrotropic bacteria than mesophilic bacteria. Results showed a maximum degradation of 47 per cent of the total petroleum hydrocarbon in columns which simulated the aquifer conditions and to which nutrients were added. It was concluded that although in this case bioaugmentation of the columns with a psychrotropic hydrocarbon-degrading consortium increased microbial numbers, total petroleum hydrocarbon degradation was not much greater than could be achieved by remediation with nutrients alone

Hydrocarbons in Argentina: networks, territories, integration

International Nuclear Information System (INIS)

Carrizo, S.C.

2003-12-01

Argentinean hydrocarbons networks have lived a huge reorganizing the structure, after the State reform in the 90's. Activities deregulation and the privatization of YPF and Gas del Estado forced the sector re-concentration, since then dominated by foreign companies, leaded by Repsol YPF. The hydrocarbons federalization contributed to the weakening and un-capitalization loss of wealth of the State. These changes resulted in an increase of the hydrocarbons production allowing to achieve the self-supply. Nevertheless, the expansion of internal networks has not been large enough to ensure the coverage of new requirements. Besides, several infrastructures have been built up to join external markets. National networks are connected to those of near neighboring countries. This integration is an opportunity for the 'South Cone' countries to enhance their potentials. In the country, hydrocarbons territories undergo the reorganizing the structure effects (unemployment, loss of territorial identity, etc). With many difficulties and very different possibilities, those territories, like Comodoro Rivadavia, Ensenada et and Bahia Blanca, look for their re-invention. (author)

Ontogenetic shifts in terrestrial reliance of stream-dwelling brown trout

Directory of Open Access Journals (Sweden)

Javier Sánchez-Hernández

2016-07-01

Full Text Available This study focuses on terrestrial reliance of brown trout (Salmo trutta and compared it to the potential prey available (macrozoobenthos and drifting invertebrates in three temperate rivers (Galicia, NW Spain, with special emphasis on variations in terrestrial energy intake through the ontogeny of brown trout. Additionally, we paid particular attention to individual variation of terrestrial resource use within and between age classes. Prey items were grouped in four categories: i aquatic invertebrates; ii imagoes of aquatic invertebrates; iii terrestrial invertebrates; and iv fish prey. Next, energy composition was measured according to dry weight-energy equations for each individual in line with above-mentioned prey categories. Our findings illustrate that terrestrial invertebrates appeared to be scarce in the environment, whereas aquatic food resources were rather abundant and accessible. The use of terrestrial invertebrates tended to increase with age, but with a high degree of inter-individual variation in resource use. In fact, the individual reliance of brown trout on terrestrial invertebrates may vary considerably (between 0% and 76.9%. Besides, the frequency of terrestrial foragers, i.e., individuals with terrestrial invertebrates in their stomachs, increased with age, except in one population which had the maximum value in the age-2 class. The acquisition of terrestrial invertebrates thus appears to be a process strongly dependent upon the actual food availability in the environment, but with a high degree of individual variance in resource use within the same age class. Finally, we discuss that terrestrial invertebrates may largely contribute to cover the energy intake of the species, highlighting the interface between terrestrial and aquatic ecosystems, and thereby the importance of riparian canopy cover as a key factor for food supply of stream-dwelling salmonids species.

Bioremediation in soil contaminated with hydrocarbons in Colombia.

OpenAIRE

María Alejandra Trujillo Toro; Juan Fernando Ramírez Quirama

2012-01-01

This study analyzes bioremediation processes of hydrocarbon contaminated soils in Colombia as a sustainable alternative to the deterioration of environmental quality by hydrocarbon spillage. According to national and international environmental law, all waste contaminated with hydrocarbons is considered dangerous waste, and therefore it cannot be released in the ground, water or be incinerated. Such legislation has motivated companies around the world to implement treatment processes for cont...

Hydrocarbon productivities in different Botryococcus strains: comparative methods in product quantification.

Science.gov (United States)

Eroglu, Ela; Okada, Shigeru; Melis, Anastasios

2011-08-01

Six different strains of the green microalgae Botryococcus belonging to the A-race or B-race, accumulating alkadiene or botryococcene hydrocarbons, respectively, were compared for biomass and hydrocarbon productivities. Biomass productivity was assessed gravimetrically upon strain growth in the laboratory under defined conditions. Hydrocarbon productivities were measured by three different and independent experimental approaches, including density equilibrium of the intact cells and micro-colonies, spectrophotometric analysis of hydrocarbon extracts, and gravimetric quantitation of eluted hydrocarbons. All three hydrocarbon-quantitation methods yielded similar results for each of the strains examined. The B-race microalgae Botryococcus braunii var. Showa and Kawaguchi-1 constitutively accumulated botryococcene hydrocarbons equivalent to 30% and 20%, respectively, of their overall biomass. The A-race microalgae Botryococcus braunii, varieties Yamanaka, UTEX 2441 and UTEX LB572 constitutively accumulated alkadiene hydrocarbons ranging from 14% to 13% and 10% of their overall biomass, respectively. Botryococcus sudeticus (UTEX 2629), a morphologically different green microalga, had the lowest hydrocarbon accumulation, equal to about 3% of its overall biomass. Results validate the density equilibrium and spectrophotometric analysis methods in the quantitation of botryococcene-type hydrocarbons. These analytical advances will serve in the screening and selection of B. braunii and of other microalgae in efforts to identify those having a high hydrocarbon content for use in commercial applications.

Priapism caused by 'Tribulus terrestris'.

Science.gov (United States)

Campanelli, M; De Thomasis, R; Tenaglia, R L

2016-01-01

A 36-year-old Caucasian man was diagnosed with a 72-h-lasting priapism that occurred after the assumption of a Herbal supplement based on Tribulus terrestris, which is becoming increasingly popular for the treatment of sexual dysfunction. The patient underwent a cavernoglandular shunt (Ebbehoj shunt) in order to obtain complete detumescence, from which derived negative post-episode outcomes on sexual function. All patients consuming non-FDA-approved alternative supplements such as Tribulus terrestris should be warned about the possible serious side effects.

Petroleum Oxidation in Marine Microcosms by Natural Microbial Assemblages

Science.gov (United States)

Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Ehrhardt, C. J.; Valentine, D. L.

2006-12-01

Millions of gallons of petroleum are emitted into marine environments each year and the oxidation of this oil by microbes is an important mechanism for mediating toxicity. In terms of quantity, petroleum is the most abundant organic pollutant impacting marine environments today. Recent advances in chromatography have led to the development of comprehensive two-dimensional gas chromatography (GC &GC). The acronym, GC GC, is used because orthogonal gas chromatographic separations are achieved in both analytical dimensions by using stationary phases with varying partitioning abilities and selectivity. This novel method has greatly expanded the analytical window of petroleum hydrocarbons and was used to track the loss of petroleum hydrocarbons in aerobic marine microcosm experiments. Sediment microcosms were composed of seawater and sediment collected from the Coal Oil Point (COP) seep field off the coast of Santa Barbara, CA. Oil collected directly from the reservoir underlying the seep field was added to each microcosm, and samples were incubated for one year. Net metabolism was tracked by quantifying oxygen consumption and carbon dioxide production. The loss of petroleum components was tracked with GC GC, whereas the bacterial and archaeal community structures were tracked using T-RFLP. Results of these incubation studies will be presented.

Radiation-induced volatile hydrocarbon production in platelets

International Nuclear Information System (INIS)

Radha, E.; Vaishnav, Y.N.; Kumar, K.S.; Weiss, J.F.

1989-01-01

Generation of volatile hydrocarbons (ethane, pentane) as a measure of lipid peroxidation was followed in preparations from platelet-rich plasma irradiated in vitro. The hydrocarbons in the headspace of sealed vials containing irradiated and nonirradiated washed platelets, platelet-rich plasma, or platelet-poor plasma increased with time. The major hydrocarbon, pentane, increased linearly and significantly with increasing log radiation dose, suggesting that reactive oxygen species induced by ionizing radiation result in lipid peroxidation. Measurements of lipid peroxidation products may give an indication of suboptimal quality of stored and/or irradiated platelets

Waste Plastic Converting into Hydrocarbon Fuel Materials

Energy Technology Data Exchange (ETDEWEB)

Sarker, Moinuddin; Mamunor Rashid, Mohammad; Molla, Mohammad

2010-09-15

The increased demand and high prices for energy sources are driving efforts to convert organic compounds into useful hydrocarbon fuels. Although much of this work has focused on biomass, there are strong benefits to deriving fuels from waste plastic material. Natural State Research Inc. (NSR) has invented a simple and economically viable process to decompose the hydrocarbon polymers of waste plastic into the shorter chain hydrocarbon of liquid fuel (patent pending). The method and principle of the production / process will be discussed. Initial tests with several widely used polymers indicate a high potential for commercialization.

Conversion of hydrocarbon oils into motor fuels

Energy Technology Data Exchange (ETDEWEB)

1937-11-09

The abstract describes a process for producing lower boiling hydrocarbon motor fuels with a starting material of wide boiling range composed primarily of hydrocarbon oils boiling substantially above the boiling range of the desired product. Separate catalytic and pyrolytic conversion zones are simultaneously maintained in an interdependent relationship. Higher boiling constituents are separated from residual constituents by fractionation while desirable reaction conditions are maintained. All or at least a portion of the products from the catalytic and pyrolytic conversion zones are blended to yield the desired lower boiling hydrocarbons or motor fuels.

Geochemistry of Natural Gas Seepages in Boto Area, Bancak, Semarang, Central Java

Directory of Open Access Journals (Sweden)

Hendra Amijaya

2017-03-01

Full Text Available DOI: 10.17014/ijog.4.2.61-70Three seepage gas samples collected from Boto Area, Bancak, Semarang, Central Java, were studied to determine their chemical characteristics using GC and GC-IRMS methods. They are composed 53 - 85% of methane predominantly. However, gas seep Site 3 sample has the highest N2 compound and the lesser extent to the samples Site 2 and Site 1 respectively. The two hydrocarbon gas seeps (Site 1, 2, and Site 3 samples that are characterized by δ13C methane of -35.61‰ and -27.97‰, and values of δD methane of -112‰ and -109‰ respectively, are each isotopically distinct from all others suggesting, at least, they are derived from different maturity level. The Site 3 gas sample is suggested to be more mature than the others.

Distilling hydrocarbons, etc

Energy Technology Data Exchange (ETDEWEB)

Turner, C

1917-11-23

In the fractional or destructive distillation of hydrocarbon oils or other liquids, the pressure in the still is raised and lowered alternately. The still is closed to raise the pressure, and is opened to lower the pressure rapidly solely by expansion of the vapors. The operation is effected without intermittent cooling, except such as may occur during the lowering of the pressure. In distilling hydrocarbon oil, pressure steam is blown into the oil until the pressure reaches 5 lb/in./sup 2/. The vapor outlet is then opened until the pressure falls to 2 lb/in./sup 2/, whereupon the vapor outlet is closed and steam is again admitted. The operation is continued until the steam, which is of 20 lb pressure, no longer effects distillation; after this stage, superheated steam is used.

Primary biodegradation of petroleum hydrocarbons in seawater

Energy Technology Data Exchange (ETDEWEB)

Comber, M.I.H.; Den Haan, K.H.; Djemel, N.; Eadsforth, C.V.; King, D.; Paumen, M.L.; Parkerton, T.; Dmytrasz, B.

2012-12-15

This report describes primary biodegradation experiments performed to determine the persistence of higher molecular weight petroleum hydrocarbons in seawater. Results from the biodegradation experiments show that the majority of tested petroleum hydrocarbons have half-lives in seawater less than 60 days.

Durable terrestrial bedrock predicts submarine canyon formation

Science.gov (United States)

Smith, Elliot; Finnegan, Noah J.; Mueller, Erich R.; Best, Rebecca J.

2017-01-01

Though submarine canyons are first-order topographic features of Earth, the processes responsible for their occurrence remain poorly understood. Potentially analogous studies of terrestrial rivers show that the flux and caliber of transported bedload are significant controls on bedrock incision. Here we hypothesize that coarse sediment load could exert a similar role in the formation of submarine canyons. We conducted a comprehensive empirical analysis of canyon occurrence along the West Coast of the contiguous United States which indicates that submarine canyon occurrence is best predicted by the occurrence of durable crystalline bedrock in adjacent terrestrial catchments. Canyon occurrence is also predicted by the flux of bed sediment to shore from terrestrial streams. Surprisingly, no significant correlation was observed between canyon occurrence and the slope or width of the continental shelf. These findings suggest that canyon incision is promoted by greater yields of durable terrestrial clasts to the shore.

Aspects of petroleum hydrocarbon metabolism in marine animals

Science.gov (United States)

Mironov, O. G.

1980-03-01

Studies on hydrocarbon composition of Black Sea mussels Mytilus galloprovincialis sampled from different habitats indicate that the quantity and composition of hydrocarbons distributed in the molluscs depend on season and sea-water quality. The data obtained under experimental conditions testify to the possibility of hydrocarbon concentration in mussel tissues after death. During filtration in sea water containing oil and oil products, these pollutants are bound into faeces and pseudofaeces which contain a greater percentage of aromatic compounds than the oil initially present in sea water. Quantitative data are presented on hydrocarbon changes in mussel excretory products during transfer from oil-polluted to clean sea water. When Black Sea crabs Eriphia verrucosa are fed with mussels containing fuel-oil components accumulated from sea water, the pollutants concentrate in the whole body of the crab. This is in contrast to parenteral oil uptake, which leads to a concentration of most of the hydrocarbon in the muscles.

Development of oil hydrocarbon fingerprinting and identification techniques

International Nuclear Information System (INIS)

Wang Zhendi; Fingas, Merv F.

2003-01-01

Oil, refined product, and pyrogenic hydrocarbons are the most frequently discovered contaminants in the environment. To effectively determine the fate of spilled oil in the environment and to successfully identify source(s) of spilled oil and petroleum products is, therefore, extremely important in many oil-related environmental studies and liability cases. This article briefly reviews the recent development of chemical analysis methodologies which are most frequently used in oil spill characterization and identification studies and environmental forensic investigations. The fingerprinting and data interpretation techniques discussed include oil spill identification protocol, tiered analytical approach, generic features and chemical composition of oils, effects of weathering on hydrocarbon fingerprinting, recognition of distribution patterns of petroleum hydrocarbons, oil type screening and differentiation, analysis of 'source-specific marker' compounds, determination of diagnostic ratios of specific oil constituents, stable isotopic analysis, application of various statistical and numerical analysis tools, and application of other analytical techniques. The issue of how biogenic and pyrogenic hydrocarbons are distinguished from petrogenic hydrocarbons is also addressed

Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea

Science.gov (United States)

Leifer, Ira; Chernykh, Denis; Shakhova, Natalia; Semiletov, Igor

2017-06-01

Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes spanning 0.019 to 1.1 L s-1 to derive the in situ calibration curve (Q(σ)). These nonlinear curves related flux (Q) to sonar return (σ) for a multibeam echosounder (MBES) and a single-beam echosounder (SBES) for a range of depths. The analysis demonstrated significant multiple bubble acoustic scattering - precluding the use of a theoretical approach to derive Q(σ) from the product of the bubble σ(r) and the bubble size distribution where r is bubble radius. The bubble plume σ occurrence probability distribution function (Ψ(σ)) with respect to Q found Ψ(σ) for weak σ well described by a power law that likely correlated with small-bubble dispersion and was strongly depth dependent. Ψ(σ) for strong σ was largely depth independent, consistent with bubble plume behavior where large bubbles in a plume remain in a focused core. Ψ(σ) was bimodal for all but the weakest plumes. Q(σ) was applied to sonar observations of natural arctic Laptev Sea seepage after accounting for volumetric change with numerical bubble plume simulations. Simulations addressed different depths and gases between calibration and seep plumes. Total mass fluxes (Qm) were 5.56, 42.73, and 4.88 mmol s-1 for MBES data with good to reasonable agreement (4-37 %) between the SBES and MBES systems. The seepage flux occurrence probability distribution function (Ψ(Q)) was bimodal, with weak Ψ(Q) in each seep area well described by a power law, suggesting primarily minor bubble plumes. The seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.

Total site integration of light hydrocarbons separation process

OpenAIRE

Ulyev, L.; Vasilyev, M.; Maatouk, A.; Duic, Neven; Khusanovc, Alisher

2016-01-01

Ukraine is the largest consumer of hydrocarbons per unit of production in Europe (Ukraine policy review, 2006). The most important point is a reduction of energy consumption in chemical and metallurgical industries as a biggest consumer. This paper deals with energy savings potential of light hydrocarbons separation process. Energy consumption of light hydrocarbons separation process processes typical of Eastern European countries were analysed. Process Integration (PI) was used to perform a ...

The Attribute for Hydrocarbon Prediction Based on Attenuation

International Nuclear Information System (INIS)

Hermana, Maman; Harith, Z Z T; Sum, C W; Ghosh, D P

2014-01-01

Hydrocarbon prediction is a crucial issue in the oil and gas industry. Currently, the prediction of pore fluid and lithology are based on amplitude interpretation which has the potential to produce pitfalls in certain conditions of reservoir. Motivated by this fact, this work is directed to find out other attributes that can be used to reduce the pitfalls in the amplitude interpretation. Some seismic attributes were examined and studies showed that the attenuation attribute is a better attribute for hydrocarbon prediction. Theoretically, the attenuation mechanism of wave propagation is associated with the movement of fluid in the pore; hence the existence of hydrocarbon in the pore will be represented by attenuation attribute directly. In this paper we evaluated the feasibility of the quality factor ratio of P-wave and S-wave (Qp/Qs) as hydrocarbon indicator using well data and also we developed a new attribute based on attenuation for hydrocarbon prediction -- Normalized Energy Reduction Stack (NERS). To achieve these goals, this work was divided into 3 main parts; estimating the Qp/Qs on well log data, testing the new attribute in the synthetic data and applying the new attribute on real data in Malay Basin data. The result show that the Qp/Qs is better than Poisson's ratio and Lamda over Mu as hydrocarbon indicator. The curve, trend analysis and contrast of Qp/Qs is more powerful at distinguishing pore fluid than Poisson ratio and Lamda over Mu. The NERS attribute was successful in distinguishing the hydrocarbon from brine on synthetic data. Applying this attribute on real data on Malay basin, the NERS attribute is qualitatively conformable with the structure and location where the gas is predicted. The quantitative interpretation of this attribute for hydrocarbon prediction needs to be investigated further

Tribulus terrestris Extract Improves Human Sperm Parameters In Vitro

Science.gov (United States)

Khaleghi, Sara; Bakhtiari, Mitra; Asadmobini, Atefeh; Esmaeili, Farzane

2016-01-01

Objective. The object of present study was to investigate the effects of direct addition of Tribulus terrestris extract on human sperm parameters. Design. Semen specimens from 40 healthy men volunteers were divided into 4 groups: one group received no treatment (control group) while the others were incubated with 20, 40, and 50 µg/mL of T terrestris extract (experimental groups). Motility, viability, and DNA fragmentation were assessed in all groups. Results. The incubation of human semen with 40 and 50 μg/mL of T terrestris extract significantly enhanced total sperm motility, number of progressive motile spermatozoa, and curvilinear velocity over 60 to 120 minutes’ holding time (P terrestris extract (P terrestris extract to human sperm could affect male fertility capacity. PMID:27694560

Tribulus terrestris Extract Improves Human Sperm Parameters In Vitro.

Science.gov (United States)

Khaleghi, Sara; Bakhtiari, Mitra; Asadmobini, Atefeh; Esmaeili, Farzane

2016-09-30

The object of present study was to investigate the effects of direct addition of Tribulus terrestris extract on human sperm parameters. Semen specimens from 40 healthy men volunteers were divided into 4 groups: one group received no treatment (control group) while the others were incubated with 20, 40, and 50 µg/mL of T terrestris extract (experimental groups). Motility, viability, and DNA fragmentation were assessed in all groups. The incubation of human semen with 40 and 50 μg/mL of T terrestris extract significantly enhanced total sperm motility, number of progressive motile spermatozoa, and curvilinear velocity over 60 to 120 minutes' holding time (P terrestris extract (P terrestris extract to human sperm could affect male fertility capacity. © The Author(s) 2016.

Study on surface geochemistry and microbiology for hydrocarbon exploration

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-01

The test results of the experimental device for extraction of dissolved gases from water show that the device can be utilized for the gas geochemistry of water. The device is capable of determining hydrocarbon gases in water to the concentration of less than 5 x 10{sup -4} ml/l of water. According to the results of microbiological studies, the plate count technique can be a useful supplementary method for hydrocarbon exploration. This is based on the facts that the average survival rate to hydrocarbons (pentane, hexane) for heterotrophs is higher in the area known as containing considerable hydrocarbon gases than other areas in the Pohang region. However, it is still necessary to develop techniques to treat the bacteria with gaseous hydrocarbons. (author). 2 figs., 41 tabs.

Hepatoprotective and Antioxidant Activities of Tribulus Terrestris

NARCIS (Netherlands)

Harraz, Fathalla M; Ghazy, Nabila M; Hammoda, Hala M; Nafeaa, Abeer A.; Abdallah, Ingy I.

2015-01-01

Tribulus terrestris L. has been used in folk medicine throughout history. The present study examined the acute toxicity of the total ethanolic extract of T. Terrestris followed by investigation of the hepatoprotective activity of the total ethanolic extract and different fractions of the aerial

Debris disks as signposts of terrestrial planet formation

Science.gov (United States)

Raymond, S. N.; Armitage, P. J.; Moro-Martín, A.; Booth, M.; Wyatt, M. C.; Armstrong, J. C.; Mandell, A. M.; Selsis, F.; West, A. A.

2011-06-01

There exists strong circumstantial evidence from their eccentric orbits that most of the known extra-solar planetary systems are the survivors of violent dynamical instabilities. Here we explore the effect of giant planet instabilities on the formation and survival of terrestrial planets. We numerically simulate the evolution of planetary systems around Sun-like stars that include three components: (i) an inner disk of planetesimals and planetary embryos; (ii) three giant planets at Jupiter-Saturn distances; and (iii) an outer disk of planetesimals comparable to estimates of the primitive Kuiper belt. We calculate the dust production and spectral energy distribution of each system by assuming that each planetesimal particle represents an ensemble of smaller bodies in collisional equilibrium. Our main result is a strong correlation between the evolution of the inner and outer parts of planetary systems, i.e. between the presence of terrestrial planets and debris disks. Strong giant planet instabilities - that produce very eccentric surviving planets - destroy all rocky material in the system, including fully-formed terrestrial planets if the instabilities occur late, and also destroy the icy planetesimal population. Stable or weakly unstable systems allow terrestrial planets to accrete in their inner regions and significant dust to be produced in their outer regions, detectable at mid-infrared wavelengths as debris disks. Stars older than ~100 Myr with bright cold dust emission (in particular at λ ~ 70 μm) signpost dynamically calm environments that were conducive to efficient terrestrial accretion. Such emission is present around ~16% of billion-year old Solar-type stars. Our simulations yield numerous secondary results: 1) the typical eccentricities of as-yet undetected terrestrial planets are ~0.1 but there exists a novel class of terrestrial planet system whose single planet undergoes large amplitude oscillations in orbital eccentricity and inclination; 2) by

Temperature-dependent mid-IR absorption spectra of gaseous hydrocarbons

International Nuclear Information System (INIS)

Klingbeil, Adam E.; Jeffries, Jay B.; Hanson, Ronald K.

2007-01-01

Quantitative mid-IR absorption spectra (2500-3400 cm -1 ) for 12 pure hydrocarbon compounds are measured at temperatures ranging from 25 to 500 deg. C using an FTIR spectrometer. The hydrocarbons studied are n-pentane, n-heptane, n-dodecane, 2,2,4-trimethyl-pentane (iso-octane), 2-methyl-butane, 2-methyl-pentane, 2,4,4-trimethyl-1-pentene, 2-methyl-2-butene, propene, toluene, m-xylene, and ethylbenzene. Room-temperature measurements of neat hydrocarbon vapor were made with an instrument resolution of both 0.1 and 1 cm -1 (FWHM) to confirm that the high-resolution setting was required only to resolve the propene absorption spectrum while the spectra of the other hydrocarbons could be resolved with 1 cm -1 resolution. High-resolution (0.1 cm -1 ), room-temperature measurements of neat hydrocarbons were made at low pressure (∼1 Torr, 133 Pa) and compared to measurements of hydrocarbon/N 2 mixtures at atmospheric pressure to verify that no pressure broadening could be observed over this pressure range. The temperature was varied between 25 and 500 o C for atmospheric-pressure measurements of hydrocarbon/N 2 mixtures (X hydrocarbon ∼0.06-1.5%) and it was found that the absorption cross section shows simple temperature-dependent behavior for a fixed wavelength over this temperature range. Comparisons with previous FTIR data over a limited temperature range and with high-resolution laser absorption data over a wide temperature range show good agreement

Method for the conversion of hydrocarbon charges

Energy Technology Data Exchange (ETDEWEB)

Whittam, T V

1976-11-11

The basis of the invention is the application of defined zeolites as catalysts to hydrocarbon conversion processes such as reformation, isomerization, dehydrocyclization, and cracking. By charging the zeolite carrier masses with 0.001 to 5% metal of the 8th group of the periodic system, preferably noble metals, a wide region of applications for the catalysts is achieved. A method for the isomerization of an alkyl benzene (or mixture of alkyl benzenes) in the liquid or gas phase under suitable temperature, pressure and flow-rate conditions, as well as in the presence of a cyclic hydrocarbon, is described as preferential model form of the invention; furthermore, a method for the reformation of a hydrocarbon fraction boiling in the gasoline or benzene boiling region and a method for the hydrocracking of hydrocarbon charge (e.g. naphtha, kerosine, gas oils) are given. Types of performance of the methods are explained using various examples.

Using microorganisms to aid in hydrocarbon degradation

International Nuclear Information System (INIS)

Black, W.; Zamora, J.

1993-01-01

Aliphatic hydrocarbons are threatening the potable water supply and the aquatic ecosystem. Given the right microbial inhabitant(s), a large portion of these aliphatic hydrocarbons could be biodegraded before reaching the water supply. The authors' purpose is to isolate possible oil-degrading organisms. Soil samples were taken from hydrocarbon-laden soils at petroleum terminals, a petroleum refinery waste-treatment facility, a sewage-treatment plant grease collector, a site of previous bioremediation, and various other places. Some isolates known to be good degraders were obtained from culture collection services. These samples were plated on a 10w-30 multigrade motor oil solid medium to screen for aliphatic hydrocarbon degraders. The degrading organisms were isolated, identified, and tested (CO 2 evolution, BOD, and COD) to determine the most efficient degrader(s). Thirty-seven organisms were tested, and the most efficient degraders were Serratia marcescens, Escherichia coli, and Enterobacter agglomerans

Nitrocarburising in ammonia-hydrocarbon gas mixtures

DEFF Research Database (Denmark)

Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

2010-01-01

The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

Fault zone controlled seafloor methane seepage in the rupture area of the 2010 Maule Earthquake, Central Chile

OpenAIRE

Geersen, Jacob; Scholz, Florian; Linke, Peter; Schmidt, Mark; Lange, Dietrich; Behrmann, Jan H.; Völker, David; Hensen, Christian

2016-01-01

Seafloor seepage of hydrocarbon-bearing fluids has been identified in a number of marine forearcs. However, temporal variations in seep activity and the structural and tectonic parameters that control the seepage often remain poorly constrained. Subduction-zone earthquakes for example, are often discussed to trigger seafloor seepage but causal links that go beyond theoretical considerations have not yet been fully established. This is mainly due to the inaccessibility of offshore epicentral a...

New insight into stratification of anaerobic methanotrophs in cold seep sediments.

Science.gov (United States)

Roalkvam, Irene; Jørgensen, Steffen Leth; Chen, Yifeng; Stokke, Runar; Dahle, Håkon; Hocking, William Peter; Lanzén, Anders; Haflidason, Haflidi; Steen, Ida Helene

2011-11-01

Methane seepages typically harbor communities of anaerobic methane oxidizers (ANME); however, knowledge about fine-scale vertical variation of ANME in response to geochemical gradients is limited. We investigated microbial communities in sediments below a white microbial mat in the G11 pockmark at Nyegga by 16S rRNA gene tag pyrosequencing and real-time quantitative PCR. A vertical stratification of dominating ANME communities was observed at 4 cmbsf (cm below seafloor) and below in the following order: ANME-2a/b, ANME-1 and ANME-2c. The ANME-1 community was most numerous and comprised single or chains of cells with typical rectangular morphology, accounting up to 89.2% of the retrieved 16S rRNA gene sequences. Detection rates for sulfate-reducing Deltaproteobacteria possibly involved in anaerobic oxidation of methane were low throughout the core. However, a correlation in the abundance of Candidate division JS-1 with ANME-2 was observed, indicating involvement in metabolisms occurring in ANME-2-dominated horizons. The white microbial mat and shallow sediments were dominated by organisms affiliated with Sulfurovum (Epsilonproteobacteria) and Methylococcales (Gammaproteobacteria), suggesting that aerobic oxidation of sulfur and methane is taking place. In intermediate horizons, typical microbial groups associated with methane seeps were recovered. The data are discussed with respect to co-occurring microbial assemblages and interspecies interactions. FEMS Microbiology Ecology © 2011 Federation of Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original Norwegian works.

The fragmentation of Pangaea and Mesozoic terrestrial vertebrate biodiversity.

Science.gov (United States)

Vavrek, Matthew J

2016-09-01

During the Mesozoic (242-66 million years ago), terrestrial regions underwent a massive shift in their size, position and connectivity. At the beginning of the era, the land masses were joined into a single supercontinent called Pangaea. However, by the end of the Mesozoic, terrestrial regions had become highly fragmented, both owing to the drifting apart of the continental plates and the extremely high sea levels that flooded and divided many regions. How terrestrial biodiversity was affected by this fragmentation and large-scale flooding of the Earth's landmasses is uncertain. Based on a model using the species-area relationship (SAR), terrestrial vertebrate biodiversity would be expected to nearly double through the Mesozoic owing to continental fragmentation, despite a decrease of 24% in total terrestrial area. Previous studies of Mesozoic vertebrates have generally found increases in terrestrial diversity towards the end of the era, although these increases are often attributed to intrinsic or climatic factors. Instead, continental fragmentation over this time may largely explain any observed increase in terrestrial biodiversity. This study demonstrates the importance that non-intrinsic effects can have on the taxonomic success of a group, and the importance of geography to understanding past biodiversity. © 2016 The Author(s).

Ancient Terrestrial Carbon: Lost and Found

Science.gov (United States)

Freeman, K. H.

2017-12-01

Carbon fluxes in terrestrial environments dominate the global carbon cycle. The fluxes of terrestrial carbon are strongly tied to regional climate due to the influences of temperature, water, and nutrient dynamics on plant productivity. However, climate also influences the destruction of terrestrial organic matter, through weathering, erosion, and biomass loss via fire and oxidative microbial processes. Organic geochemical methods enable us to interrogate past terrestrial carbon dynamics and learn how continental processes might accelerate, or mitigate carbon transfer to the atmosphere, and the associated greenhouse warming. Terrestrial soil systems represent the weathering rind of the continents, and are inherently non-depositional and erosive. The production, transport, and depositional processes affecting organics in continental settings each impart their own biases on the amount and characteristics of preserved carbon. Typically, the best archives for biomarker records are sediments in ancient lakes or subaqueous fans, which represents a preservation bias that tends to favor wetter environments. Paleosols, or ancient soils, formed under depositional conditions that, for one reason or another, truncated soil ablation, erosion, or other loss processes. In modern soils, widely ranging organic carbon abundances are almost always substantially greater than the trace amounts of carbon left behind in ancient soils. Even so, measureable amounts of organic biomarkers persist in paleosols. We have been investigating processes that preserve soil organic carbon on geologic timescales, and how these mechanisms may be sensitive to past climate change. Climate-linked changes in temperature, moisture, pH, and weathering processes can impact carbon preservation via organo-mineral sorption, soil biogeochemistry, and stability based on the physical and chemical properties of organic compounds. These will be discussed and illustrated with examples from our studies of Cenozoic

George A. Olah, Carbocation and Hydrocarbon Chemistry

Science.gov (United States)

dropdown arrow Site Map A-Z Index Menu Synopsis George A. Olah, Carbocation and Hydrocarbon Chemistry George Olah received the 1994 Nobel Prize in Chemistry "for his contribution to carbocation chemistry" and his 'role in the chemistry of hydrocarbons. In particular, he developed superacids

Accelerator mass analyses of meteorites - carbon-14 terrestrial ages

International Nuclear Information System (INIS)

Miura, Y.; Rucklidge, J.; Beukens, R.; Fireman, E.

1988-01-01

Carbon-14 terrestrial ages of ten Antarctic meteorites have been measured by the IsoTrace accelerator mass spectrometry (AMS). The 14 C terrestrial age of 1 gram sample was determined from 14 C concentrations collected at melt and re-melt temperatures, compared with the 14 C concentration of the known Bruderheim chondrite. Yamato-790448 (LL3) chondrite was found to be the oldest terrestrial age of 3x10 4 years in the nine Yamato chondrites, whereas Yamato-791630 (L4) chondrite is considered to be the youngest chondrites less than thousand years. Allan Hills chondrite of ALH-77231 (L6) shows older terrestrial age than the nine Yamato chondrites. New accelerator data of the terrestrial age show higher accuracy with smaller sample than the previous counting method. (author)

Detection of irradiated meats by hydrocarbon method

International Nuclear Information System (INIS)

Goto, Michiko; Miyakawa, Hiroyuki; Fujinuma, Kenji; Ozawa, Hideki

2005-01-01

Meats, for example, lamb, razorback, wild duck and turkey were irradiated by gamma ray, and the amounts of hydrocarbons formed from fatty acids were measured. Since C 20:0 was found from wild duck and turkey. C 1-18:1 was recommended for internal standard. Good correlation was found between the amount of hydrocarbons and the doses of gamma irradiation. This study shows that such hydrocarbons induced after radiation procedure as C 1,7-16:2 , C 8-17:1 , C 1-14:1 , and C 15:0 may make it possible to detect irradiated lamb, razorback, wild duck and turkey. (author)

Method of recovering hydrocarbons from oil shale

Energy Technology Data Exchange (ETDEWEB)

Walton, D.K.; Slusser, M.S.

1970-11-24

A method is described for recovering hydrocarbons from an oil-shale formation by in situ retorting. A well penetrating the formation is heated and gas is injected until a pressure buildup within the well is reached, due to a decrease in the conductivity of naturally occurring fissures within the formation. The well is then vented, in order to produce spalling of the walls. This results in the formation of an enlarged cavity containing rubberized oil shale. A hot gas then is passed through the rubberized oil shale in order to retort hydrocarbons and these hydrocarbons are recovered from the well. (11 claims)

Bioremediation of petroleum hydrocarbons in soil environments

International Nuclear Information System (INIS)

Rowell, M.J.; Ashworth, J.; Qureshi, A.A.

1992-12-01

The bioremediation of petroleum hydrocarbons in soil environments was reviewed via a literature survey and discussions with workers in relevant disciplines. The impacts of hydrocarbons on soil are discussed along with a range of methods available to assist in their decomposition by soil microorganisms. The range of petroleum-based materials considered includes conventional and synthetic crude oils, refined oils, sludges, asphalts and bitumens, drilling mud residues, creosote tars, and some pesticides. The degradability of hydrocarbons largely depends upon their aqueous solubility and their adsorption on soil surfaces and, therefore, is related to their molecular structures. The ease of decomposition decreases with increasing complexity of structure, in the order aliphatics > aromatics > heterocyclics and asphaltenes (most recalcitrant). Most soils contain an adequate population of microorganisms and hence bioaugmentation may only be needed in special circumstances. Decomposition is fastest in soils where the hydrocarbon loading rate, aeration, nutrition, moisture, and pH are all optimized. At spill sites there is little control over the application rate, although containment measures can assist in either limiting contamination or distributing it more evenly. The enhancement of bioremediation is discussed in light of all these factors. Other techniques such as enhanced aeration, hydrocarbon decomposition by anaerobic processes, surfactants, and burning are also discussed. 211 refs., 11 figs., 10 tabs

Emissions of hydrocarbons from combustion of biofuels

International Nuclear Information System (INIS)

Olsson, Mona; Persson, Eva Marie.

1991-10-01

Evaluations and measurements of emissions of hydrocarbons from power plants with a capacity exceeding 1 MW using biofuels (wood fuels and peat) have been studied in order to identify and quantify the emissions of incompletely combusted hydrocarbons. The influence of the type of fuel and the combustion technology applied were also studied, using literature references. The report summarizes monitoring results from a number of plants using biofuels. The reported emissions from the different plants can not be compared as they are relatively few and the test results have been obtained under various conditions using different methods of testing and analysis. The methods used are often poorly documented in the studied reports. Few investigations of emissions of hydrocarbons from plants in the range of 1 to 10 MW have been carried out. The plant and the technology used are important factors determining the amount and type of emissions of hydrocarbons. Larger temporary emissions can occur during start up, operational disturbances or when using fuel of inhomogeneous quality. In order to minimize the emissions the combustion process must be efficiently controlled, and a fuel of a hohogeneous quality must be used. The report also summarizes sampling and analysis methods used for monitoring emissions of hydrocarbons. (29 refs., 17 figs.)

Bioremediation of petroleum hydrocarbons in soil environments

Energy Technology Data Exchange (ETDEWEB)

Rowell, M J; Ashworth, J; Qureshi, A A

1992-12-01

The bioremediation of petroleum hydrocarbons in soil environments was reviewed via a literature survey and discussions with workers in relevant disciplines. The impacts of hydrocarbons on soil are discussed along with a range of methods available to assist in their decomposition by soil microorganisms. The range of petroleum-based materials considered includes conventional and synthetic crude oils, refined oils, sludges, asphalts and bitumens, drilling mud residues, creosote tars, and some pesticides. The degradability of hydrocarbons largely depends upon their aqueous solubility and their adsorption on soil surfaces and, therefore, is related to their molecular structures. The ease of decomposition decreases with increasing complexity of structure, in the order aliphatics > aromatics > heterocyclics and asphaltenes (most recalcitrant). Most soils contain an adequate population of microorganisms and hence bioaugmentation may only be needed in special circumstances. Decomposition is fastest in soils where the hydrocarbon loading rate, aeration, nutrition, moisture, and pH are all optimized. At spill sites there is little control over the application rate, although containment measures can assist in either limiting contamination or distributing it more evenly. The enhancement of bioremediation is discussed in light of all these factors. Other techniques such as enhanced aeration, hydrocarbon decomposition by anaerobic processes, surfactants, and burning are also discussed. 211 refs., 11 figs., 10 tabs.

Structure of the terrestrial planets

International Nuclear Information System (INIS)

Lyttleton, R.A.

1977-01-01

Recent reviews (cf. Runcorn, 1968; or Cook, 1972, 1975) on the structure of the planets omit reference to the phase-change hypothesis for the nature of the terrestrial core, despite that numerous prior predictions of the theory based on this hypothesis have subsequently been borne out as correct. These reviews also ignore the existence of theoretical calculations of the internal structure of Venus which can be computed with high accuracy by use of the terrestrial seismic data. Several examples of numerous mistakes committed in these reviews are pointed out. (Auth.)

Hydrocarbon phytoremediation in the family Fabaceae--a review.

Science.gov (United States)

Hall, Jessica; Soole, Kathleen; Bentham, Richard

2011-04-01

Currently, studies often focus on the use of Poaceae species (grasses) for phytoremediation of hydrocarbon-contaminated soils. Research into the use of Fabaceae species (legumes) to remediate hydrocarbons in soils has been conducted, but these plants are commonly overlooked due to slower recorded rates of degradation compared with many grass species. Evidence in the literature suggests that in some cases Fabaceae species may increase total degradation of hydrocarbons and stimulate degradative capacity of the soil microbial community, particularly for contaminants which are normally more recalcitrant to degradation. As many recalcitrant hydrocarbons have negative impacts on human and ecosystem health, development of remediation options is crucial. Reconsideration of Fabaceae species for removal of such contaminants may lead to environmentally and economically sustainable technologies for remediation of contaminated sites.

The role of mass spectrometry in hydrocarbon analysis

International Nuclear Information System (INIS)

Kerenyi, E.

1980-01-01

Modern mass spectrometry has an outstandin.o role in solving problems concerning the composition and structure of hydrocarbon mixtures and their derivatives, petroleum and petrochemical products. Its efficiency in hydrocarbon analysis has been increased not only by high resolving power and computerized spectrum processing but also by the metastable ion spectrum technique promoting structural examinations, by mild ionization facilitating composition analysis, and by selective ion-detecting technique. The author presents the advantages of the metastable ion spectra, the field ionization, field desorption and other mild ionization methods, and finally, those of fragmentation analysis in connection with the examination of hydrocarbons and hydrocarbon derivatives. Examples taken from the literature and from the research work carried out in the Institute are also given. (author)

Enhancement of in situ Remediation of Hydrocarbon Contaminated Soil

Energy Technology Data Exchange (ETDEWEB)

Palmroth, M.

2006-07-01

Approximately 750 000 sites of contaminated land exist across Europe. The harmful chemicals found in Finnish soils include heavy metals, oil products, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorophenols, and pesticides. Petroleum and petroleum products enter soil from ruptured oil pipelines, land disposal of refinery products, leaking storage tanks and through accidents. PAH contamination is caused by the spills of coal tar and creosote from coal gasification and wood treatment sites in addition to oil spills. Cleanup of soil by bioremediation is cheaper than by chemical and physical processes. However, the cleaning capacity of natural attenuation and in situ bioremediation is limited. The purpose of this thesis was to find feasible options to enhance in situ remediation of hydrocarbon contaminants. The aims were to increase the bioavailability of the contaminants and microbial activity at the subsurface in order to achieve higher contaminant removal efficiency than by intrinsic biodegradation alone. Enhancement of microbial activity and decrease of soil toxicity during remediation were estimated by using several biological assays. The performance of these assays was compared in order to find suitable indicators to follow the progress of remediation. Phytoremediation and chemical oxidation are promising in situ techniques to increase the degradation of hydrocarbons in soil. Phytoremediation is plant-enhanced decontamination of soil and water. Degradation of hydrocarbons is enhanced in the root zone by increased microbial activity and through the detoxifying enzymes of plants themselves. Chemical oxidation of contaminants by Fenton's reaction can produce degradation products which are more biodegradable than the parent compounds. Fenton's reaction and its modifications apply solutions of hydrogen peroxide and iron for the oxidation of organic chemicals. The cost of oxidation can be reduced by aiming at partial instead of full

Community Decadal Panel for Terrestrial Analogs to Mars

Science.gov (United States)

Barlow, N. G.; Farr, T.; Baker, V. R.; Bridges, N.; Carsey, F.; Duxbury, N.; Gilmore, M. S.; Green, J. R.; Grin, E.; Hansen, V.; Keszthelyi, L.; Lanagan, P.; Lentz, R.; Marinangeli, L.; Morris, P. A.; Ori, G. G.; Paillou, P.; Robinson, C.; Thomson, B.

2001-11-01

It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites for Mars, instrument tests, laboratory measurements (including analysis of martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel is considering the following two key questions: (1) How do terrestrial analog studies tie in to the MEPAG science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel is considering the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

Nitrocarburizing in ammonia-hydrocarbon gas mixtures

DEFF Research Database (Denmark)

Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

2011-01-01

The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

Terrestrial magnetosphere

International Nuclear Information System (INIS)

Pande, D.C.; Agarwal, D.C.

1982-01-01

This paper presents a review about terrestrial magnetosphere. During the last few years considerable investigation have been carried out about the properties of Solar Wind and its interaction with planetary magnetic fields. It is therefore of high importance to accumulate all the investigations in a comprehensive form. The paper reviews the property of earth's magnetosphere, magnetosheath, magneto pause, polar cusps, bow shook and plasma sheath. (author)

Source identification of hydrocarbons following environmental releases

Energy Technology Data Exchange (ETDEWEB)

Birkholz, D.A. [ALS Environmental, Edmonton, AB (Canada)

2010-07-01

Methods of identifying the sources of hydrocarbon contaminations were discussed in this PowerPoint presentation. Laboratories analyze for total petroleum hydrocarbons (TPH) by obtaining chromatograms of observed products. However, many petroleum products provide similar chromatograms. Several independent lines of evidence are needed for the purposes of accurate determination in legal applications. A case study of a lube oil plant spill was used to demonstrate the inconclusiveness of chromatograms and the need to determine petroleum biomarkers. Terpane, sterane, triaromatic sterane, isoprenoid, and alkylcyclohexane analyses were conducted to differentiate between the hydrocarbon samples. The analysis methods are being used with various soil, water, and crab species samples from the BP oil spill. Oil found at the different sites must be directly related to the spill. However, there are 3858 oil and gas platforms currently operating in the Gulf of Mexico. Ratios of biomarkers and polycyclic aromatic hydrocarbons (PAHs) are being developed to generate weight of evidence. A critical difference analysis was also presented. tabs., figs.

Structural segregation of petroleum and prospective hydrocarbon regions in Azerbaijan

International Nuclear Information System (INIS)

Kerimov, K.M.; Huseynov, A.N.; Hajiyev, F.M.

2002-01-01

Full text : Structural segregation allows identify the earth crust blocks according to their geological setting and structural history conductive for hydrocarbon generation and their entrapment in the sedimentary fill reservoirs. Since then there has been a need to design a new tectonic map of petroleum and hydrocarbons potential systems in Azerbaijan embracing both on- and offshore areas. Map's legend designed upon above mentioned concepts and principles has made it possible to evaluate the role of individual stratigraphic units in hydrocarbon generation and its entrapment, as well as in recognition of regional structural criteria of the hydrocarbon bearing potential of different structural patterns. Tectonic map of petroleum and prospective hydrocarbon bearing on and offshore areas in Azerbaijan for the first time contained a wide range of information related to structural criteria of hydrocarbon bearing potential, sedimentary fill's structural architecture, its thickness, both timing of their formation stages and basement consolidation, its subsidence depth, as well as hydrocarbon deposit areal and vertical distribution across individual regions. This map was considered to be of important implication both for the petroleum geoscience and petroleum industry endeavors.

Introduced Terrestrial Species (Future)

Data.gov (United States)

U.S. Environmental Protection Agency — These data represent predicted future potential distributions of terrestrial plants, animals, and pathogens non-native to the Middle-Atlantic region. These data are...

Chemical fingerprinting of hydrocarbon-contamination in soil.