Cold seeps and splay faults on Nankai margin

NASA Astrophysics Data System (ADS)

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

Discovery of asphalt seeps in the deep Southwest Atlantic off Brazil

NASA Astrophysics Data System (ADS)

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

Methane seeps along boundaries of arctic permafrost thaw and melting glaciers

NASA Astrophysics Data System (ADS)

Anthony, P.; Walter Anthony, K. M.; Grosse, G.; Chanton, J.

2014-12-01

Methane, a potent greenhouse gas, accumulates in subsurface hydrocarbon reservoirs. In the Arctic, impermeable icy permafrost and glacial overburden form a 'cryosphere cap' that traps gas leaking from these reservoirs, restricting flow to the atmosphere. We document the release of geologic methane to the atmosphere from abundant gas seeps concentrated along boundaries of permafrost thaw and receding glaciers in Alaska. Through aerial and ground surveys we mapped >150,000 seeps identified as bubbling-induced open holes in lake ice. Subcap methane seeps had anomalously high fluxes, 14C-depletion, and stable isotope values matching known coalbed and thermogenic methane accumulations in Alaska. Additionally, we observed younger subcap methane seeps in Greenland that were associated with ice-sheet retreat since the Little Ice Age. These correlations suggest that in a warming climate, continued disintegration of permafrost, glaciers, and parts of the polar ice sheets will relax pressure on subsurface seals and further open conduits, allowing a transient expulsion of geologic methane currently trapped by the cryosphere cap.

Iron oxides stimulate sulfate-driven anaerobic methane oxidation in seeps

DOE PAGES

Sivan, Orit; Antler, Gilad; Turchyn, Alexandra V.; ...

2014-09-22

Seep sediments are dominated by intensive microbial sulfate reduction coupled to the anaerobic oxidation of methane (AOM). Through geochemical measurements of incubation experiments with methane seep sediments collected from Hydrate Ridge, we provide insight into the role of iron oxides in sulfate-driven AOM. Seep sediments incubated with 13C-labeled methane showed co-occurring sulfate reduction, AOM, and methanogenesis. The isotope fractionation factors for sulfur and oxygen isotopes in sulfate were about 40‰ and 22‰, respectively, reinforcing the difference between microbial sulfate reduction in methane seeps versus other sedimentary environments (for example, sulfur isotope fractionation above 60‰ in sulfate reduction coupled to organicmore » carbon oxidation or in diffusive sedimentary sulfate–methane transition zone). The addition of hematite to these microcosm experiments resulted in significant microbial iron reduction as well as enhancing sulfate-driven AOM. The magnitude of the isotope fractionation of sulfur and oxygen isotopes in sulfate from these incubations was lowered by about 50%, indicating the involvement of iron oxides during sulfate reduction in methane seeps. The similar relative change between the oxygen versus sulfur isotopes of sulfate in all experiments (with and without hematite addition) suggests that oxidized forms of iron, naturally present in the sediment incubations, were involved in sulfate reduction, with hematite addition increasing the sulfate recycling or the activity of sulfur-cycling microorganisms by about 40%. Furthermore, these results highlight a role for natural iron oxides during bacterial sulfate reduction in methane seeps not only as nutrient but also as stimulator of sulfur recycling.« less

Groundwater seeps in Taylor Valley Antarctica: an example of a subsurface melt event

NASA Astrophysics Data System (ADS)

Lyons, W. Berry; Welch, Kathleen A.; Carey, Anne E.; Doran, Peter T.; Wall, Diana H.; Virginia, Ross A.; Fountain, Andrew G.; Csathó, Bea M.; Tremper, Catherine M.

The 2001/02 austral summer was the warmest summer on record in Taylor Valley, Antarctica, (˜78° S) since continuous records of temperature began in 1985. The highest stream-flows ever recorded in the Onyx River, Wright Valley, were also recorded that year (the record goes back to the 1969/70 austral summer). In early January 2002, a groundwater seep was observed flowing in the southwest portion of Taylor Valley. This flow has been named 'Wormherder Creek' (WHC) and represents an unusual event, probably occurring on a decadal time-scale. The physical characteristics of this feature suggest that it may have flowed at other times in the past. Other groundwater seeps, emanating from the north-facing slope of Taylor Valley, were also observed. Little work has been done previously on these very ephemeral seeps, and the source of water is unknown. These features, resembling recently described features on Mars, represent the melting of subsurface ice. The Martian features have been interpreted as groundwater seeps. In this paper we compare the chemistry of the WHC groundwater seep to that of the surrounding streams that flow every austral summer. The total dissolved solids content of WHC was ˜6 times greater than that of some nearby streams. The Na : Cl and SO4 : Cl ratios of the seep waters are higher than those of the streams, but the Mg : Cl and HCO3 : Cl ratios are lower, indicating different sources of solutes to the seeps compared to the streams. The enrichment of Na and SO4 relative to Cl may suggest significant dissolution of mirabilite within the previously unwetted soil. The proposed occurrence of abundant mirabilite in higher-elevation soils of the dry valley region agrees with geochemical models developed, but not tested, in the late 1970s. The geochemical data demonstrate that these seeps could be important in 'rinsing' the soils by dissolving and redistributing the long-term accumulation of salts, and perhaps improving habitat suitability for soil biota

Microbial communities of deep-sea methane seeps at Hikurangi continental margin (New Zealand).

PubMed

Ruff, S Emil; Arnds, Julia; Knittel, Katrin; Amann, Rudolf; Wegener, Gunter; Ramette, Alban; Boetius, Antje

2013-01-01

The methane-emitting cold seeps of Hikurangi margin (New Zealand) are among the few deep-sea chemosynthetic ecosystems of the Southern Hemisphere known to date. Here we compared the biogeochemistry and microbial communities of a variety of Hikurangi cold seep ecosystems. These included highly reduced seep habitats dominated by bacterial mats, partially oxidized habitats populated by heterotrophic ampharetid polychaetes and deeply oxidized habitats dominated by chemosynthetic frenulate tubeworms. The ampharetid habitats were characterized by a thick oxic sediment layer that hosted a diverse and biomass-rich community of aerobic methanotrophic Gammaproteobacteria. These bacteria consumed up to 25% of the emanating methane and clustered within three deep-branching groups named Marine Methylotrophic Group (MMG) 1-3. MMG1 and MMG2 methylotrophs belong to the order Methylococcales, whereas MMG3 methylotrophs are related to the Methylophaga. Organisms of the groups MMG1 and MMG3 are close relatives of chemosynthetic endosymbionts of marine invertebrates. The anoxic sediment layers of all investigated seeps were dominated by anaerobic methanotrophic archaea (ANME) of the ANME-2 clade and sulfate-reducing Deltaproteobacteria. Microbial community analysis using Automated Ribosomal Intergenic Spacer Analysis (ARISA) showed that the different seep habitats hosted distinct microbial communities, which were strongly influenced by the seep-associated fauna and the geographic location. Despite outstanding features of Hikurangi seep communities, the organisms responsible for key ecosystem functions were similar to those found at seeps worldwide. This suggests that similar types of biogeochemical settings select for similar community composition regardless of geographic distance. Because ampharetid polychaetes are widespread at cold seeps the role of aerobic methanotrophy may have been underestimated in seafloor methane budgets.

Microbial Communities of Deep-Sea Methane Seeps at Hikurangi Continental Margin (New Zealand)

PubMed Central

Ruff, S. Emil; Arnds, Julia; Knittel, Katrin; Amann, Rudolf; Wegener, Gunter; Ramette, Alban; Boetius, Antje

2013-01-01

The methane-emitting cold seeps of Hikurangi margin (New Zealand) are among the few deep-sea chemosynthetic ecosystems of the Southern Hemisphere known to date. Here we compared the biogeochemistry and microbial communities of a variety of Hikurangi cold seep ecosystems. These included highly reduced seep habitats dominated by bacterial mats, partially oxidized habitats populated by heterotrophic ampharetid polychaetes and deeply oxidized habitats dominated by chemosynthetic frenulate tubeworms. The ampharetid habitats were characterized by a thick oxic sediment layer that hosted a diverse and biomass-rich community of aerobic methanotrophic Gammaproteobacteria. These bacteria consumed up to 25% of the emanating methane and clustered within three deep-branching groups named Marine Methylotrophic Group (MMG) 1-3. MMG1 and MMG2 methylotrophs belong to the order Methylococcales, whereas MMG3 methylotrophs are related to the Methylophaga . Organisms of the groups MMG1 and MMG3 are close relatives of chemosynthetic endosymbionts of marine invertebrates. The anoxic sediment layers of all investigated seeps were dominated by anaerobic methanotrophic archaea (ANME) of the ANME-2 clade and sulfate-reducing Deltaproteobacteria. Microbial community analysis using Automated Ribosomal Intergenic Spacer Analysis (ARISA) showed that the different seep habitats hosted distinct microbial communities, which were strongly influenced by the seep-associated fauna and the geographic location. Despite outstanding features of Hikurangi seep communities, the organisms responsible for key ecosystem functions were similar to those found at seeps worldwide. This suggests that similar types of biogeochemical settings select for similar community composition regardless of geographic distance. Because ampharetid polychaetes are widespread at cold seeps the role of aerobic methanotrophy may have been underestimated in seafloor methane budgets. PMID:24098632

Behavioural impairment in reef fishes caused by ocean acidification at CO2 seeps

NASA Astrophysics Data System (ADS)

Munday, Philip L.; Cheal, Alistair J.; Dixson, Danielle L.; Rummer, Jodie L.; Fabricius, Katharina E.

2014-06-01

Experiments have shown that the behaviour of reef fishes can be seriously affected by projected future carbon dioxide (CO2) concentrations in the ocean. However, whether fish can acclimate to elevated CO2 over the longer term, and the consequences of altered behaviour on the structure of fish communities, are unknown. We used marine CO2 seeps in Papua New Guinea as a natural laboratory to test these questions. Here we show that juvenile reef fishes at CO2 seeps exhibit behavioural abnormalities similar to those seen in laboratory experiments. Fish from CO2 seeps were attracted to predator odour, did not distinguish between odours of different habitats, and exhibited bolder behaviour than fish from control reefs. High CO2 did not, however, have any effect on metabolic rate or aerobic performance. Contrary to expectations, fish diversity and community structure differed little between CO2 seeps and nearby control reefs. Differences in abundances of some fishes could be driven by the different coral community at CO2 seeps rather than by the direct effects of high CO2. Our results suggest that recruitment of juvenile fish from outside the seeps, along with fewer predators within the seeps, is currently sufficient to offset any negative effects of high CO2 within the seeps. However, continuous exposure does not reduce the effect of high CO2 on behaviour in natural reef habitat, and this could be a serious problem for fish communities in the future when ocean acidification becomes widespread as a result of continued uptake of anthropogenic CO2 emissions.

Anaerobic methane oxidation in low-organic content methane seep sediments

USGS Publications Warehouse

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

2013-01-01

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

Geologic Significance of Newly Discovered Methane Seeps on the Northern US Atlantic Margin

NASA Astrophysics Data System (ADS)

Skarke, A. D.; Ruppel, C. D.; Kodis, M.; Lobecker, E.; Malik, M.

2013-12-01

identified within the GHSZ, but do not yet appear to be associated with salt diapirism or any other geological phenomena with the capacity to drive active methane expulsion at the seafloor. Repeat acoustic and video surveys at an ~500 m2 seep field south of Nantucket Island demonstrated that some seeps are characterized by continuous gas emission, whereas other proximal seeps exhibit episodic gas emission with a temporal variability on the order of hours to days. While significant ephemerality of methane emission at the scale of individual plumes has been verified, ROV imagery of massive, but isolated, patches of authigenic carbonate and well-developed chemosynthetic communities suggest that emission of methane at the scale of the seep field has been persistent over hundreds to thousands of years.

Hydrocarbon seeps in petroliferous basins in China: A first inventory

NASA Astrophysics Data System (ADS)

Zheng, Guodong; Xu, Wang; Etiope, Giuseppe; Ma, Xiangxian; Liang, Shouyun; Fan, Qiaohui; Sajjad, Wasim; Li, Yang

2018-01-01

Natural hydrocarbon seepage is a widespread phenomenon in sedimentary basins, with important implications in petroleum exploration and emission of greenhouse gases to the atmosphere. China has vast petroleum (oil and gas) bearing sedimentary basins, but hydrocarbon seepage has rarely been the object of systematic studies and measurements. Based on the available Chinese literature, we report a first inventory of 932 hydrocarbon seeps or seepage zones (710 onshore seeps and 222 offshore seeps), including 81 mud volcanoes, 449 oil seeps, 215 gas seeps, and 187 solid seeps (bitumen outcrops). The seeps are located within the main 20 Mesozoic-Cenozoic petroliferous sedimentary basins, especially along the marginal, regional and local faults. The type of manifestations (oil, gas or mud volcano) reflects the type and maturity of the subsurface petroleum system and the sedimentary conditions of the basin. Oil seeps are particularly abundant in the Junggar Basin. Gas seeps mostly developed in the Lunpola Basin, in smaller basins of the eastern Guizhou and Yunnan provinces, onshore Taiwan and in the offshore Yinggehai Basin. Mud volcanoes developed in basins (Junggar, Qaidam, Qiangtang, onshore and offshore Taiwan) that experienced rapid sedimentation, which induced gravitative instability of shales and diapirism. In comparison to available global onshore seep data-bases, China results to be the country with the highest number of seeps in the world. The massive gas seepage in China could represent a considerable natural source of methane to the atmosphere, and a key process that may drive future hydrocarbon exploration.

Hydrologic investigation and remediation of a post-remining acidic seep

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

Aljoe, W.W.; Linberg, N.A.

1996-12-31

Surface remining of coal pillars in abandoned underground workings in the Pittsburgh seam in southwestern Pennsylvania has often resulted in post-remining discharges whose water quality is the same or better than the pre-existing discharges. However, at one such operation in Washington County, PA, an increase in contaminant loading occurred at an outcrop seep after remining. This problem was believed to be at least partly related to a small unstrapped area of the old deep mine workings immediately upgradient from the seep. A hydrologic investigation that included a chemical tracer test, slug tests in the remined spoil, and water quality monitoringmore » indicated that the mine pool in the old workings discharged through the seep. However, the water in the mine pool and much of the remined spoil was consistently alkaline; this suggested that the acidic water may have originated in other areas of the spoil and old workings, and passed rapidly to the seep through a highly transmissive portion of the spoil. Acting on this assumption, the mine operator successfully implemented a remediation scheme in which the spoil was excavated to intercept the acidic spoil water. The excavation was then re-emplaced with an anoxic limestone drain at its base. The drain now serves both to add alkalinity to the water and to divert the seep to an area where metals can be removed easily via precipitation in wetlands.« less

Low-tar and high-tar cigarettes

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

Holt, P.G.; Chalmer, J.E.; Roberts, L.M.

Mice were exposed for 7 to 8 minutes on weekdays to fresh smoke from high-tar (HT) or low-tar (LT) cigarettes for varying periods of up to 36 weeks. Mice exposed to HT cigarettes exhibited more marked alterations in humoral immune responsiveness, hematological profiles, and pulmonary pathologic findings than those exposed to LT cigarettes. However, cell-mediated immune responsiveness to both bacterial and tumor-specific antigens was depressed similarly in animals exposed to HT or LT cigarettes. Furthermore, the growth rates of subcutaneously established tumors were enhanced similarly in the two groups, with respect to those in control animals.

The temporal relationship between advertising and sales of low-tar cigarettes.

PubMed

Reed, Mark B; Anderson, Christy M; Burns, David M

2006-12-01

To determine whether a temporal relationship exists between the advertising and sales of low-tar cigarettes. It was hypothesised that increases in the advertising of low-tar cigarettes would precede increases in sales for these cigarettes. The themes of cigarette advertisements were reviewed and coded for 20 low-tar cigarette brands advertised in 13 widely read magazines in the US between 1960 and 1996. These 20 brands represented most of the low-tar cigarette advertisements and cigarette sales from 1967 to 1996. Cigarette sales data were obtained from the 1994 Maxwell report that summarises all cigarette sales from 1925 to 1990. If the advertisement referred to the low-tar attributes of the cigarette advertised, the advertisement was coded as having a low-tar theme and was included in the analysis. Five different graphical presentations of the relationship between the advertising and sales of the 20 low-tar cigarette brands showed a temporal relationship between low-tar advertising and sales for these brands. This relationship was observed for brands that introduced a low-tar alternative into an existing brand family (eg, Marlboro Light) and for new exclusively low-tar brands (eg, Carlton). Despite large increases in the advertising for the exclusively low-tar brands, sales of these brands remained low relative to sales of the low-tar alternative brands. Increases in print advertising of 20 of the most popular low-tar cigarette brands were followed by increases in sales for these cigarettes. Despite increases in the advertising of exclusively low-tar brands in the mid-1970s and early 1980s, the sales of these brands never matched the sales of the low-tar alternative brands. This suggests that it may have been easier to get smokers to switch to low-tar brands within a brand family compared with entirely new low-tar brands. Over the past 30 years, the marketing of low-tar cigarettes as a healthier alternative to higher-tar cigarettes has resulted in these brands

Topical tar: Back to the future

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

Paghdal, K.V.; Schwartz, R.A.

2009-08-15

The use of medicinal tar for dermatologic disorders dates back to the ancient times. Although coal tar is utilized more frequently in modern dermatology, wood tars have also been widely employed. Tar is used mainly in the treatment of chronic stable plaque psoriasis, scalp psoriasis, atopic dermatitis, and seborrheic dermatitis, either alone or in combination therapy with other medications, phototherapy, or both. Many modifications have been made to tar preparations to increase their acceptability, as some dislike its odor, messy application, and staining of clothing. One should consider a tried and true treatment with tar that has led to clearingmore » of lesions and prolonged remission times. Occupational studies have demonstrated the carcinogenicity of tar; however, epidemiologic studies do not confirm similar outcomes when used topically. This article will review the pharmacology, formulations, efficacy, and adverse effects of crude coal tar and other tars in the treatment of selected dermatologic conditions.« less

Biogeography and Potential Exchanges Among the Atlantic Equatorial Belt Cold-Seep Faunas

PubMed Central

Olu, Karine; Cordes, Erik E.; Fisher, Charles R.; Brooks, James M.; Sibuet, Myriam; Desbruyères, Daniel

2010-01-01

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 3300m, 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 2000m, with the middle slope sites either grouped with those deeper than 2000m 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 should be further

Emission of Methane and Heavier Alkanes From the La Brea Tar Pits Seepage Area, Los Angeles

NASA Astrophysics Data System (ADS)

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

2017-11-01

Natural hydrocarbon (oil and gas) seeps are widespread in Los Angeles, California, 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) to the atmosphere, in addition to anthropogenic fossil fuel and biogenic sources. We measured the CH4 flux by closed-chamber method from the La Brea Tar Pits park (0.1 km2), one of the largest seepage sites in Los Angeles. The gas seepage occurs throughout the park, not only from visible oil-asphalt seeps but also diffusely from the soil, affecting grass physiology. About 500 kg CH4 d-1 is emitted from the park, especially along a belt of enhanced degassing that corresponds to the 6th Street Fault. Additional emissions are from bubble plumes in the lake within the park (order of 102-103 kg d-1) and at the intersection of Wilshire Boulevard and Curson Avenue (>130 kg d-1), along the same fault. The investigated area has the highest natural gas flux measured thus far for any onshore seepage zone in the USA. Gas migration, oil biodegradation, and secondary methanogenesis altered the molecular composition of the original gas accumulated in the Salt Lake Oil Field (>300 m deep), leading to high C1/C2+ and i-butane/n-butane ratios. These molecular alterations can be important tracers of natural seepage and should be considered in the atmospheric modeling of the relative contribution of fossil fuel (anthropogenic fugitive emission and natural geologic sources) versus biogenic sources of methane, on local and global scales.

The temporal relationship between advertising and sales of low‐tar cigarettes

PubMed Central

Reed, Mark B; Anderson, Christy M; Burns, David M

2006-01-01

Objective and hypothesis To determine whether a temporal relationship exists between the advertising and sales of low‐tar cigarettes. It was hypothesised that increases in the advertising of low‐tar cigarettes would precede increases in sales for these cigarettes. Methods The themes of cigarette advertisements were reviewed and coded for 20 low‐tar cigarette brands advertised in 13 widely read magazines in the US between 1960 and 1996. These 20 brands represented most of the low‐tar cigarette advertisements and cigarette sales from 1967 to 1996. Cigarette sales data were obtained from the 1994 Maxwell report that summarises all cigarette sales from 1925 to 1990. If the advertisement referred to the low‐tar attributes of the cigarette advertised, the advertisement was coded as having a low‐tar theme and was included in the analysis. Results Five different graphical presentations of the relationship between the advertising and sales of the 20 low‐tar cigarette brands showed a temporal relationship between low‐tar advertising and sales for these brands. This relationship was observed for brands that introduced a low‐tar alternative into an existing brand family (eg, Marlboro Light) and for new exclusively low‐tar brands (eg, Carlton). Despite large increases in the advertising for the exclusively low‐tar brands, sales of these brands remained low relative to sales of the low‐tar alternative brands. Conclusions Increases in print advertising of 20 of the most popular low‐tar cigarette brands were followed by increases in sales for these cigarettes. Despite increases in the advertising of exclusively low‐tar brands in the mid‐1970s and early 1980s, the sales of these brands never matched the sales of the low‐tar alternative brands. This suggests that it may have been easier to get smokers to switch to low‐tar brands within a brand family compared with entirely new low‐tar brands. Over the past 30 years, the marketing of low‐tar

Recognition of Fossil Prokaryotes in Cretaceous Methane Seep Carbonates: Relevance to Astrobiology

NASA Astrophysics Data System (ADS)

Shapiro, Russell Scott

2004-12-01

Recovery of prokaryotic body fossils from methane seep carbonates such as those of the Cretaceous Tepee Buttes of Colorado serves as a model for sampling in future astrobiological missions. The fossils, found primarily at the interface between paragenetic fabrics, suggest a sharp physicochemical gradient. Evidence of these microbial fossils occurs at a variety of scales. In the field, microbialite is found as meter-scale thrombolitic zones and centimeterscale stromatolitic crusts lining voids inferred to be the sites of ancient methane seepage. Petrographic fabrics suggestive of microbialite include indistinct peloids (0.1-1 mm in diameter) and crusts of authigenic micrite. Primary evidence obtained from scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy analysis comprises pinnate bacteria (0.3 µm in diameter and 1-1.5 µm long), sheaths (2-4 µm in diameter), coccoids (0.5-1 µm in diameter, up to 40 per cluster), and the presence of framboidal pyrite (6-8 µm in diameter). These results are in agreement with studies of other ancient and modern seeps and suggest a morphological conservatism of microbial form that can be incorporated into studies of extraterrestrial environments where it is presumed that reduced gases drive the metabolic activity of prokaryote-like organisms. Target areas that could serve as conduits for reduced gas seeps include tectonic or impact-driven faulting, zones of cryosphere melting, or other disruptions in crustal coherence. Ancient seeps, preserved as localized anomalous evaporite deposits in the sedimentary cover, could be detected by remote sensing. Astrobiology 4, 438-449.

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

PubMed

Portail, Marie; Olu, Karine; Dubois, Stanislas F; Escobar-Briones, Elva; Gelinas, Yves; Menot, Lénaick; Sarrazin, Jozée

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 partly release the

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

PubMed Central

Olu, Karine; Dubois, Stanislas F.; Escobar-Briones, Elva; Gelinas, Yves; Menot, Lénaick; Sarrazin, Jozée

2016-01-01

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 partly release the

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

NASA Astrophysics Data System (ADS)

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

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

PubMed

Bowden, David A; Rowden, Ashley A; Thurber, Andrew R; Baco, Amy R; Levin, Lisa A; Smith, Craig R

2013-01-01

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.

Cold Seep Epifaunal Communities on the Hikurangi Margin, New Zealand: Composition, Succession, and Vulnerability to Human Activities

PubMed Central

Bowden, David A.; Rowden, Ashley A.; Thurber, Andrew R.; Baco, Amy R.; Levin, Lisa A.; Smith, Craig R.

2013-01-01

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. PMID:24204691

The potential use of tar sand bitumen as paving asphalt

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

Petersen, J.C.

1988-01-01

In this paper several research reports describing the preparation of potential paving asphalts from tar sand bitumen are reviewed and the results of the studies compared. The tar sand asphalts described in the studies were prepared from 1) hot water-recovered bitumen from deposits near San Luis Obispo, California (Edna deposits), and deposits near Vernal and Sunnyside, Utah; and 2) bitumen recovered from the Northwest Asphalt Ridge deposits near Vernal, Utah, by both in situ steamflood and in situ combustion recovery processes. Important properties of the tar sand asphalts compare favorably with those of specification petroleum asphalts. Laboratory data suggest thatmore » some tar sand asphalts may have superior aging characteristics and produce more water-resistant paving mixtures than typical petroleum asphalts.« less

The earliest mollusc dominated seep fauna from the Early Jurassic of Argentina

NASA Astrophysics Data System (ADS)

Kaim, Andrzej; Jenkins, Robert; Parent, Horacio; Garrido, Alberto; Moriya, Kazuhiro

2015-04-01

The earliest mollusc dominated seep fauna from the Early Jurassic of Argentina Andrzej Kaim, Robert G. Jenkins, Horacio Parent, Alberto C. Garrido The hydrocarbon seep deposits are known from Early Jurassic of Argentina since the report of Gomez-Perez (2003). The latter author identified very negative δ13C values (down to -33) and several fabrics typical for seep carbonates. Nevertheless she identified no macrofaunal assemblages apart from worm tubes. We re-visited the locality of Gomez-Perez (named here La Elina) and we were able to collect several molluscs associated with the seep carbonate. The most common and diversified are molluscs and worm tubes. We identified at least three species of gastropods, including the oldest-known species of neomphalids, lucinid and protobranch bivalves and numerous ammonoids. Unlike another known Early Jurassic seep from Oregon and the only Late Triassic seep (also from Oregon) there are no brachiopods associated with this seep. Therefore we consider the seep at La Elina as the oldest seep of modern aspect where the fauna is dominated by molluscs and not brachiopods.

Methane Seep Carbonates Host Distinct, Diverse, and Dynamic Microbial Assemblages

PubMed Central

Pasulka, Alexis L.; Marlow, Jeffrey J.; Grupe, Benjamin M.; Levin, Lisa A.

2015-01-01

ABSTRACT Marine methane seeps are globally distributed geologic features in which reduced fluids, including methane, are advected upward from the subsurface. As a result of alkalinity generation during sulfate-coupled methane oxidation, authigenic carbonates form slabs, nodules, and extensive pavements. These carbonates shape the landscape within methane seeps, persist long after methane flux is diminished, and in some cases are incorporated into the geologic record. In this study, microbial assemblages from 134 native and experimental samples across 5,500 km, representing a range of habitat substrates (carbonate nodules and slabs, sediment, bottom water, and wood) and seepage conditions (active and low activity), were analyzed to address two fundamental questions of seep microbial ecology: (i) whether carbonates host distinct microbial assemblages and (ii) how sensitive microbial assemblages are to habitat substrate type and temporal shifts in methane seepage flux. Through massively parallel 16S rRNA gene sequencing and statistical analysis, native carbonates are shown to be reservoirs of distinct and highly diverse seep microbial assemblages. Unique coupled transplantation and colonization experiments on the seafloor demonstrated that carbonate-associated microbial assemblages are resilient to seep quiescence and reactive to seep activation over 13 months. Various rates of response to simulated seep quiescence and activation are observed among similar phylogenies (e.g., Chloroflexi operational taxonomic units) and similar metabolisms (e.g., putative S oxidizers), demonstrating the wide range of microbial sensitivity to changes in seepage flux. These results imply that carbonates do not passively record a time-integrated history of seep microorganisms but rather host distinct, diverse, and dynamic microbial assemblages. PMID:26695630

Enumeration of viruses and prokaryotes in deep-sea sediments and cold seeps of the Gulf of Mexico

USGS Publications Warehouse

Kellogg, Christina A.

2010-01-01

Little is known about the distribution and abundance of viruses in deep-sea cold-seep environments. Like hydrothermal vents, seeps support communities of macrofauna that are sustained by chemosynthetic bacteria. Sediments close to these communities are hypothesized to be more microbiologically active and therefore to host higher numbers of viruses than non-seep areas. Push cores were taken at five types of Gulf of Mexico habitats at water depths below 1000 m using a remotely operated vehicle (ROV). The habitats included non-seep reference sediment, brine seeps, a microbial mat, an urchin field, and a pogonophoran worm community. Samples were processed immediately for enumeration of viruses and prokaryotes without the addition of a preservative. Prokaryote counts were an order of magnitude lower in sediments directly in contact with macrofauna (urchins, pogonophorans) compared to all other samples (107 vs. 108 cells g-1 dry weight) and were highest in areas of elevated salinity (brine seeps). Viral-Like Particle (VLP) counts were lowest in the reference sediments and pogonophoran cores (108 VLP g-1 dry wt), higher in brine seeps (109 VLP g-1 dry wt), and highest in the microbial mats (1010 VLP g-1 dry wt). Virus-prokaryote ratios (VPR) ranged from <5 in the reference sediment to >30 in the microbial mats and >60 in the urchin field. VLP counts and VPR were all significantly greater than those reported from sediments in the deep Mediterranean Sea and in most cases were higher than recent data from a cold-seep site near Japan. The high VPR suggest that greater microbial activity in or near cold-seep environments results in greater viral production and therefore higher numbers of viruses.

Enumeration of viruses and prokaryotes in deep-sea sediments and cold seeps of the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Kellogg, Christina A.

2010-11-01

Little is known about the distribution and abundance of viruses in deep-sea cold-seep environments. Like hydrothermal vents, seeps support communities of macrofauna that are sustained by chemosynthetic bacteria. Sediments close to these communities are hypothesized to be more microbiologically active and therefore to host higher numbers of viruses than non-seep areas. Push cores were taken at five types of Gulf of Mexico habitats at water depths below 1000 m using a remotely operated vehicle (ROV). The habitats included non-seep reference sediment, brine seeps, a microbial mat, an urchin field, and a pogonophoran worm community. Samples were processed immediately for enumeration of viruses and prokaryotes without the addition of a preservative. Prokaryote counts were an order of magnitude lower in sediments directly in contact with macrofauna (urchins, pogonophorans) compared to all other samples (107 vs. 108 cells g-1 dry weight) and were highest in areas of elevated salinity (brine seeps). Viral-Like Particle (VLP) counts were lowest in the reference sediments and pogonophoran cores (108 VLP g-1 dry wt), higher in brine seeps (109 VLP g-1 dry wt), and highest in the microbial mats (1010 VLP g-1 dry wt). Virus-prokaryote ratios (VPR) ranged from <5 in the reference sediment to >30 in the microbial mats and >60 in the urchin field. VLP counts and VPR were all significantly greater than those reported from sediments in the deep Mediterranean Sea and in most cases were higher than recent data from a cold-seep site near Japan. The high VPR suggest that greater microbial activity in or near cold-seep environments results in greater viral production and therefore higher numbers of viruses.

Can hydrocarbons entrapped in seep carbonates serve as gas geochemistry recorder?

NASA Astrophysics Data System (ADS)

Blumenberg, Martin; Pape, Thomas; Seifert, Richard; Bohrmann, Gerhard; Schlömer, Stefan

2018-04-01

The geochemistry of seep gases is useful for an understanding of the local petroleum system. Here it was tested whether individual light hydrocarbons in seep gases are representatively entrapped in authigenic carbonates that formed near active seep sites. If applicable, it would be possible to extract geochemical information not only on the origin but also on the thermal maturity of the hydrocarbon source rocks from the gases entrapped in carbonates in the past. Respective data could be used for a better understanding of paleoenvironments and might directly serve as calibration point for, amongst others, petroleum system modeling. For this approach, (sub)-recent seep carbonates from the Black Sea (Paleodnjepr region and Batumi seep area), two sites of the Campeche Knoll region in the Gulf of Mexico, and the Venere mud volcano (Mediterranean Sea) were selected. These seep carbonates derive from sites for which geochemical data on the currently seeping gases exist. During treatment with phosphoric acid, methane and higher hydrocarbons were released from all carbonates, but in low concentrations. Compositional studies demonstrate that the ratio of methane to the sum of higher hydrocarbons (C1/(C2+C3)) is (partly strongly) positively biased in the entrapped gas fraction. δ13C values of C1 were determined for all samples and, for the samples from the Gulf of Mexico and the Mediterranean Sea, also of C2 and C3. The present dataset from six seep sites indicates that information on the seeped methane can be—although with a scatter of several permil—recorded in seep carbonate matrices, but other valuable information like the composition and δ13C of ethane and propane appears to be modified or lost during, for example, enclosure or at an early stage of diagenesis.

Spatial scales of bacterial community diversity at cold seeps (Eastern Mediterranean Sea)

PubMed Central

Pop Ristova, Petra; Wenzhöfer, Frank; Ramette, Alban; Felden, Janine; Boetius, Antje

2015-01-01

Cold seeps are highly productive, fragmented marine ecosystems that form at the seafloor around hydrocarbon emission pathways. The products of microbial utilization of methane and other hydrocarbons fuel rich chemosynthetic communities at these sites, with much higher respiration rates compared with the surrounding deep-sea floor. Yet little is known as to the richness, composition and spatial scaling of bacterial communities of cold seeps compared with non-seep communities. Here we assessed the bacterial diversity across nine different cold seeps in the Eastern Mediterranean deep-sea and surrounding seafloor areas. Community similarity analyses were carried out based on automated ribosomal intergenic spacer analysis (ARISA) fingerprinting and high-throughput 454 tag sequencing and were combined with in situ and ex situ geochemical analyses across spatial scales of a few tens of meters to hundreds of kilometers. Seep communities were dominated by Deltaproteobacteria, Epsilonproteobacteria and Gammaproteobacteria and shared, on average, 36% of bacterial types (ARISA OTUs (operational taxonomic units)) with communities from nearby non-seep deep-sea sediments. Bacterial communities of seeps were significantly different from those of non-seep sediments. Within cold seep regions on spatial scales of only tens to hundreds of meters, the bacterial communities differed considerably, sharing <50% of types at the ARISA OTU level. Their variations reflected differences in porewater sulfide concentrations from anaerobic degradation of hydrocarbons. This study shows that cold seep ecosystems contribute substantially to the microbial diversity of the deep-sea. PMID:25500510

Methane seeps along boundaries of receding glaciers in Alaska and Greenland

NASA Astrophysics Data System (ADS)

Walter Anthony, K. M.; Anthony, P. M.; Grosse, G.; Chanton, J.

2012-12-01

. 1650-1850 C.E.). Across Alaska, we found a relationship between methane stable isotopes, radiocarbon age, and distance to faults. Faults appear to allow the escape of deeper, more 14C-depleted methane to the atmosphere, whereas seeps away from faults entrained 14C-enriched methane formed in shallower sediments from microbial decomposition of younger organic matter. Additionally, we observed younger subcap methane seeps in lakes of Greenland's Sondrestrom Fjord that were associated with ice-sheet retreat since the LIA. These correlations suggest that in a warming climate, continued disintegration of glaciers, permafrost, and parts of the polar ice sheets will weaken subsurface seals and further open conduits, allowing a transient expulsion of methane currently trapped by the cryosphere cap.

Transverse Aeolian Ridges (TARs) on Mars II: Distributions, orientations, and ages

NASA Astrophysics Data System (ADS)

Berman, Daniel C.; Balme, Matthew R.; Rafkin, Scot C. R.; Zimbelman, James R.

2011-05-01

) climate data for both surface wind shear stress and wind direction. We performed GCM runs at various obliquity values to simulate the effects of changing obliquity on recent Mars climate. We found good general agreement between TAR orientation and GCM wind directions from present day obliquity conditions in many cases, but found no good correlation between wind shear stress and TAR distribution. We performed preliminary high resolution crater count studies of TARs in both equatorial and southern intracrater dunefield settings and compared these to superposition relationships between TARs and large dark dunes. Our results show that TARs near dunefield appear to be younger than TARs in the equatorial regions. We infer that active saltation from the large dunes keeps TARs active, but that TARs are not active under present day condition when distal to large dunes - perhaps supporting the interpretation that TARs are granule ripples. We conclude that local geology, rather than wind strength, controls TAR distribution, but that their orientation matches present-day regional wind patterns in most cases. We suggest that TARs are likely most (perhaps only) active today when they are proximal to large dark dune fields.

Process for hydrogenation of hydrocarbon tars

DOEpatents

Dolbear, Geoffrey E.

1978-07-18

Hydrocarbon tars of high asphaltene content such as tars obtained from pyrolysis of coal are dissolved in a solvent formed from the hydrogenation of the coal tars, and the resultant mixture hydrogenated in the presence of a catalyst at a pressure from about 1500 to 5000 psig at a temperature from about 500.degree. F to about the critical temperature of the solvent to form a light hydrocarbon as a solvent for the tars. Hydrogen content is at least three times the amount of hydrogen consumed.

Sulfur isotope and porewater geochemistry of Florida escarpment seep sediments

USGS Publications Warehouse

Chanton, J.P.; Martens, C.S.; Paull, C.K.; Coston, J.A.

1993-01-01

Distributions of porewater constituents, SO4=, NH4+, Cl-, ???CO2, and H2S, solid phase iron, and sulfur concentrations, and the sulfur isotopic composition of dissolved and solid phases were investigated in sediments from abyssal seeps at the base of the Florida escarpment. Despite the apparent similarity of seep sediment porewater chemistry to that of typical marine sediments undergoing early diagenesis, relationships between chemical distributions and isotopic measurements revealed that the distribution of pore fluid constituents was dominated by processes occurring within the platform rather than by in situ microbial processes. Ammonium and sulfate concentrations were linearly correlated with chloride concentrations, indicating that variations in porewater chemistry were controlled by the admixture of seawater and a sulfate depleted brine with a chlorinity of 27.5 ?? 1.9%. and 2.2 ?? 1.3 mM ammonium concentration. At sites dominated by seepage, dissolved sulfate isotopic composition remained near seawater values despite depletion in porewater concentrations. Porewater ???CO2 concentrations were found to be elevated relative to seawater, but not to the extent predicted from the observed sulfate depletion. Sediment solid phase sulfur was predominantly pyrite, at concentrations as high as 20% S by weight. In contrast to typical marine deposits, pyrite concentrations were not related to the quantity of sedimentary organic matter. Pyrite ??34S values ranged from -29%. to + 21%. (CDT). However, only positive ??34S values were observed at sites associated with high pyrite concentrations. Isotopically heavy pyrite was observed at sites with porewater sulfate of seawater-like isotopic composition. Isotopically light pyrite was associated with sites where porewater sulfate exhibited ??34S values greater than those in seawater, indicating the activity of in situ microbial sulfate reduction. Thus, dual sulfide sources are suggested to explain the range in sediment pyrite

Method for treatment of tar-bearing fuel gas

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

Frauen, L.L.; Kasper, S.

1986-01-07

A process is described of producing a fuel gas which contains condensable tar vapor when it leaves a gasifier, the improvement wherein the tar-bearing gases are treated to remove tar therefrom. The process consists of: (a) continuously conducting hot fuel gas from a gasifier to and discharging it into a spray chamber where the hot tar-bearing gas is contacted with a fine spray of water thereby cooling the tar vapor and evaporating the water to produce a fog-like dispersion of tar in an atmosphere of fuel gas with the temperature in the spray chamber maintained above the dew point ofmore » water; (b) continuously transferring the fuel gas and the dispersion of tar and water to an electrostatic precipitator and precipitating therein at least most of the condensed tar as a liquid; (c) removing the liquid tar so precipitated and conducting at least most of it to a tar burner; (d) burning the tar with no more than the stoichiometric supply of oxygen provided by air to produce oxygen-free and tar-free hot combustion gases; (e) conducting the hot combustion gases directly into a mixer into which the fuel gas and water vapor flows from the precipitator, thereby adding to the fuel gas the sensible heat of the combustion gases; and (f) conducting the mixture so produced to a place of use as a hot fuel gas mixture.« less

Facultative methanotrophs are abundant at terrestrial natural gas seeps.

PubMed

Farhan Ul Haque, Muhammad; Crombie, Andrew T; Ensminger, Scott A; Baciu, Calin; Murrell, J Colin

2018-06-28

Natural gas contains methane and the gaseous alkanes ethane, propane and butane, which collectively influence atmospheric chemistry and cause global warming. Methane-oxidising bacteria, methanotrophs, are crucial in mitigating emissions of methane as they oxidise most of the methane produced in soils and the subsurface before it reaches the atmosphere. Methanotrophs are usually obligate, i.e. grow only on methane and not on longer chain alkanes. Bacteria that grow on the other gaseous alkanes in natural gas such as propane have also been characterised, but they do not grow on methane. Recently, it was shown that the facultative methanotroph Methylocella silvestris grew on ethane and propane, other components of natural gas, in addition to methane. Therefore, we hypothesised that Methylocella may be prevalent at natural gas seeps and might play a major role in consuming all components of this potent greenhouse gas mixture before it is released to the atmosphere. Environments known to be exposed to biogenic methane emissions or thermogenic natural gas seeps were surveyed for methanotrophs. 16S rRNA gene amplicon sequencing revealed that Methylocella were the most abundant methanotrophs in natural gas seep environments. New Methylocella-specific molecular tools targeting mmoX (encoding the soluble methane monooxygenase) by PCR and Illumina amplicon sequencing were designed and used to investigate various sites. Functional gene-based assays confirmed that Methylocella were present in all of the natural gas seep sites tested here. This might be due to its ability to use methane and other short chain alkane components of natural gas. We also observed the abundance of Methylocella in other environments exposed to biogenic methane, suggesting that Methylocella has been overlooked in the past as previous ecological studies of methanotrophs often used pmoA (encoding the alpha subunit of particulate methane monooxygenase) as a marker gene. New biomolecular tools designed in

Gammaproteobacterial Methanotrophs Dominate Cold Methane Seeps in Floodplains of West Siberian Rivers

PubMed Central

Oshkin, Igor Y.; Wegner, Carl-Eric; Lüke, Claudia; Glagolev, Mikhail V.; Filippov, Illiya V.; Pimenov, Nikolay V.; Liesack, Werner

2014-01-01

A complex system of muddy fluid-discharging and methane (CH4)-releasing seeps was discovered in a valley of the river Mukhrinskaya, one of the small rivers of the Irtysh Basin, West Siberia. CH4 flux from most (90%) of these gas ebullition sites did not exceed 1.45 g CH4 h−1, while some seeps emitted up to 5.54 g CH4 h−1. The δ13C value of methane released from these seeps varied between −71.1 and −71.3‰, suggesting its biogenic origin. Although the seeps were characterized by low in situ temperatures (3.5 to 5°C), relatively high rates of methane oxidation (15.5 to 15.9 nmol CH4 ml−1 day−1) were measured in mud samples. Fluorescence in situ hybridization detected 107 methanotrophic bacteria (MB) per g of mud (dry weight), which accounted for up to 20.5% of total bacterial cell counts. Most (95.8 to 99.3%) methanotroph cells were type I (gammaproteobacterial) MB. The diversity of methanotrophs in this habitat was further assessed by pyrosequencing of pmoA genes, encoding particulate methane monooxygenase. A total of 53,828 pmoA gene sequences of seep-inhabiting methanotrophs were retrieved and analyzed. Nearly all of these sequences affiliated with type I MB, including the Methylobacter-Methylovulum-Methylosoma group, lake cluster 2, and several as-yet-uncharacterized methanotroph clades. Apparently, microbial communities attenuating methane fluxes from these local but strong CH4 sources in floodplains of high-latitude rivers have a large proportion of potentially novel, psychrotolerant methanotrophs, thereby providing a challenge for future isolation studies. PMID:25063667

Deciphering structure-activity relationships in a series of Tat/TAR inhibitors.

PubMed

Pascale, Lise; González, Alejandro López; Di Giorgio, Audrey; Gaysinski, Marc; Teixido Closa, Jordi; Tejedor, Roger Estrada; Azoulay, Stéphane; Patino, Nadia

2016-11-01

A series of pentameric "Polyamide Amino Acids" (PAAs) compounds derived from the same trimeric precursor have been synthesized and investigated as HIV TAR RNA ligands, in the absence and in the presence of a Tat fragment. All PAAs bind TAR with similar sub-micromolar affinities but their ability to compete efficiently with the Tat fragment strongly differs, IC50 ranging from 35 nM to >2 μM. While NMR and CD studies reveal that all PAA interact with TAR at the same site and induce globally the same RNA conformational change upon binding, a comparative thermodynamic study of PAA/TAR equilibria highlights distinct TAR binding modes for Tat competitor and non-competitor PAAs. This led us to suggest two distinct interaction modes that have been further validated by molecular modeling studies. While the binding of Tat competitor PAAs induces a contraction at the TAR bulge region, the binding of non-competitor ones widens it. This could account for the distinct PAA ability to compete with Tat fragment. Our work illustrates how comparative thermodynamic studies of a series of RNA ligands of same chemical family are of value for understanding their binding modes and for rationalizing structure-activity relationships.

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

USGS Publications Warehouse

McGann, Mary; Conrad, James E.

2018-01-01

deep infaunal species of Globobulimina, the shallow infaunal species Uvigerina peregrina, the epifaunal species Cibicidoides wuellerstorfi, and the shallow infaunal but aragonite-shelled species Hoeglundina elegans. The δ13C values downcore among each benthic species indicates ongoing fluid seepage through at least the last 3800 cal yr B.P. at Southeast Seep. Besides the continual local seepage, evidence from δ13C values of planktic foraminifera in the seep core suggest two pulses of methane (at 3000 and 3700 cal yr B.P.) were released that were large enough to influence much of the water column. Paired benthic and planktic foraminiferal stable oxygen isotope records provide evidence that there were no paleoenvironmental changes such as increased bottom-water temperature or changes in oxygen isotopic composition of bottom and pore waters during this 3800-year record to induce the methane releases. Instead, Southeast Seep appears to be the result of local faulting providing pathways for fluid to flow to the seafloor at a fault stepover or transpressional bend in the regional strike-slip system.

Field Exploration of Methane Seep Near Atqasuk

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

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{submore » 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.« less

Natural gas seeps in the French Alps: Sources and pathways

NASA Astrophysics Data System (ADS)

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

Morphology of transverse aeolian ridges (TARs) on Mars from a large sample: Further evidence of a megaripple origin?

NASA Astrophysics Data System (ADS)

Hugenholtz, Chris H.; Barchyn, Thomas E.; Boulding, Adam

2017-04-01

Using HiRISE digital terrain models (DTMs), we developed a large morphological dataset to examine the three-dimensional shape, size, and scaling of Martian transverse aeolian ridges (TARs). Considerable debate exists on the characteristic morphology of TARs and the origins of these enigmatic bedforms. Some researchers suggest polygenesis or multiple classes of similar bedforms. Reliably characterizing the morphology of TARs is an essential prerequisite to developing and evaluating process-based models of TAR genesis and unraveling aeolian processes on the surface of Mars. We present measurements of TAR morphology from a large, DTM-derived dataset (n = 2295). We focused on TARs with 'simple' morphologies in order enable more defensible discretization. Histograms and cumulative log-frequency plots of morphometric parameters (length, width, height, elongation ratio, and wavelength) indicate the sample represents a continuum of bedforms from a single population. A typical TAR from our dataset is 88.5 m long (longest planview axis), 17.3 m wide (shortest planview axis), 1.3 m tall, and has a wavelength of 25.8 m. Combined with these data, the bulk of evidence presented to date suggests that interpreting TARs as megaripples is the most viable working hypothesis.

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

USGS Publications Warehouse

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.

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

NASA Astrophysics Data System (ADS)

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

2010-11-01

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 δ13C and δ15N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light δ15N and δ13C values, indicating possible reliance on chemoautotrophic symbioses. The lightest δ13C and δ15N values were observed in nematodes (δ13C=-54.6±0.1‰, δ15N=-6.1±0.2‰) and one gastropod (δ13C=-54.1‰, δ15N=-1.1‰) 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.

Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates.

PubMed

Bryer, Pamela J; Scoggins, Mateo; McClintock, Nancy L

2010-05-01

Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, & 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments. Copyright 2009 Elsevier Ltd. All rights reserved.

40 CFR 721.10532 - Tar, brown coal.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tar, brown coal. 721.10532 Section 721... Tar, brown coal. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as tar, brown coal (PMN P-12-167, CAS No. 101316-83-0) is subject to...

40 CFR 721.10532 - Tar, brown coal.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tar, brown coal. 721.10532 Section 721... Tar, brown coal. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as tar, brown coal (PMN P-12-167, CAS No. 101316-83-0) is subject to...

Assessing the health risks of natural CO2 seeps in Italy

PubMed Central

Roberts, Jennifer J.; Wood, Rachel A.; Haszeldine, R. Stuart

2011-01-01

Industrialized societies which continue to use fossil fuel energy sources are considering adoption of Carbon Capture and Storage (CCS) technology to meet carbon emission reduction targets. Deep geological storage of CO2 onshore faces opposition regarding potential health effects of CO2 leakage from storage sites. There is no experience of commercial scale CCS with which to verify predicted risks of engineered storage failure. Studying risk from natural CO2 seeps can guide assessment of potential health risks from leaking onshore CO2 stores. Italy and Sicily are regions of intense natural CO2 degassing from surface seeps. These seeps exhibit a variety of expressions, characteristics (e.g., temperature/flux), and location environments. Here we quantify historical fatalities from CO2 poisoning using a database of 286 natural CO2 seeps in Italy and Sicily. We find that risk of human death is strongly influenced by seep surface expression, local conditions (e.g., topography and wind speed), CO2 flux, and human behavior. Risk of accidental human death from these CO2 seeps is calculated to be 10-8 year-1 to the exposed population. This value is significantly lower than that of many socially accepted risks. Seepage from future storage sites is modeled to be less that Italian natural flux rates. With appropriate hazard management, health risks from unplanned seepage at onshore storage sites can be adequately minimized. PMID:21911398

Treating tar sands formations with karsted zones

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael

2010-03-09

Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

Use of LANDSAT-1 data for the detection and mapping of saline seeps in Montana

NASA Technical Reports Server (NTRS)

May, G. A. (Principal Investigator); Petersen, G. W.

1976-01-01

The author has identified the following significant results. April, May, and August are the best times to detect saline seeps. Specific times within these months would be dependent upon weather, phenology, and growth conditions. Saline seeps can be efficiently and accurately mapped, within resolution capabilities, from merged May and August LANDSAT 1 data. Seeps were mapped by detecting salt crusts in the spring and indicator plants in the fall. These indicator plants were kochia, inkweed, and foxtail barley. The total hectares of the mapped saline seeps were calculated and tabulated. Saline seeps less than two hectares in size or that have linear configurations less than 200 meters in width were not mapped using the LANDSAT 1 data. Saline seep signatures developed in the Coffee Creek test site were extended to map saline seeps located outside this area.

seeping gas

NASA Astrophysics Data System (ADS)

Carlowicz, Michael

On a recent cruise of the Russian research ship Professor Logachev, scientists from the U.S. Naval Research Laboratory (NRL), the Russian research institute VNI-IOkeangeologia (St. Petersburg), and other institutions found what they believe to be thin white sheets of methane hydrates. The white layer (possibly also mats of chemosynthetic bacteria) covers the center of a deep-sea mud volcano in the Norwegian-Greenland Sea. The Haakon Mosby mud volcano—a “cow-pie-shaped” cold seep that is 1 km in diameter—lies at 1250-m depth and south of Spitsbergen, Norway.

Lessons in microbial geochemistry from the Coal Oil Point seep field: progress as prospects.

NASA Astrophysics Data System (ADS)

Valentine, D. L.; Kinnaman, F.; Wardlaw, G.; Redmond, M.; Ding, H.; Kimball, J.; Busso, L.; Larson, A.

2005-12-01

The hydrocarbon seeps located offshore Coal Oil Point, Santa Barbara, CA, are estimated to emit 1010 grams of methane and 50 thousand barrels of oil annually, and are among the most prolific in the world. The seep field spans a range of shelf depths and many of the seeps are accessible by SCUBA, making this an ideal location to investigate the impact of microbes on the biogeochemical cycling of methane and other hydrocarbons. With funding provided by the National Science Foundation, the Minerals Management Service and the Petroleum Research Fund, we have begun to investigate the interactions between microbes, hydrocarbon distributions, and environmental dynamics in the seep environment. This presentation will provide an overview of Coal Oil Point seep field and the biogeochemical research being conducted there. Several topics will be incorporated including i) the dynamics of oil and gas seepage, ii) the microbial consumption of methane, ethane, propane, butane and crude oil, iii) the distribution and composition of microbial mats, iv) redox differentiation in seep sediments and the importance of advection, and v) the development of experimental tools for the investigation of seep environments. Prospects for future biochemical research in the Coal Oil Point seep field will also be discussed.

Tar Management and Recycling in Biomass Gasification and Syngas Purification

NASA Astrophysics Data System (ADS)

McCaffrey, Zach

Removal of tars is critical to the design and operation of biomass gasification systems as most syngas utilization processing equipment (e.g. internal combustion engines, gas turbines, fuel cells, and liquid fuel synthesis reactors) have a low tolerance for tar. Capturing and disposal of tar is expensive due to equipment costs, high hazardous waste disposal costs where direct uses cannot be found, and system energy losses incurred. Water scrubbing is an existing technique commonly used in gasification plants to remove contaminants and tar; however using water as the absorbent is non-ideal as tar compounds have low or no water solubility. Hydrophobic solvents can improve scrubber performance and this study evaluated tar solubility in selected solvents using slip-streams of untreated syngas from a laboratory fluidized bed reactor operated on almond composite feedstock using both air and steam gasification. Tar solubility was compared with Hansen's solubility theory to examine the extent to which the tar removal can be predicted. As collection of tar without utilization leads to a hazardous waste problem, the study investigated the effects of recycling tars back into the gasifier for destruction. Prior to experiments conducted on tar capture and recycle, characterizations of the air and steam gasification of the almond composite mix were made. This work aims to provide a better understanding of tar collection and solvent selection for wet scrubbers, and to provide information for designing improved tar management systems for biomass gasification.

Method for filtering solvent and tar sand mixtures

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

Kelterborn, J. C.; Stone, R. A.

1985-09-03

A method for filtering spent tar sands from a bitumen and organic solvent solution comprises separating the solution into two streams wherein the bulk of the coarser spent tar sand is in a first stream and has an average particle size of about 10 to about 100 mesh and the bulk of the finer spent tar sand is in a second stream; producing a filter cake by filtering the coarser spent tar sand from the first stream; and filtering the finer spent tar sand from the second stream with the filter cake. The method is particularly useful for filtering solutionsmore » of bitumen extracted from bitumen containing diatomite, spent diatomite and organic solvent.« less

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

NASA Astrophysics Data System (ADS)

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.

Intense gas bubble emissions in the Kerch seep area - A newly discovered high-flux seep site in the Black Sea

NASA Astrophysics Data System (ADS)

Römer, M.; Sahling, H.; Pape, T.; Bahr, A.; Feseker, T.; Wintersteller, P.; Bohrmann, G.

2012-04-01

suggested that gas discharge varied spatially and temporally while the total number of flares remained rather constant. During seafloor inspections with MARUḾs remotely operated vehicle 'ROV QUEST 4000 m' gas bubble emission sites were investigated in detail. Gas bubbles collected during the ROV dives mainly consisted of methane predominantly of microbial origin. By analyzing the high-definition video material the gas flux from several bubble emission sites was calculated. In combination with the hydroacoustic results (flare distributions) it is estimated that about 2.2 - 87 × 106 mol CH4/yr are emitted from the seafloor at the Kerch seep area. Despite this high mass of methane injected into the hydrosphere, the peak of the highest flares at ~350 m water depth as revealed by echosounder recording suggest that the ascending methane completely dissolves in the water column and does not pass the sea-atmosphere boundary.

Final safety assessment of Coal Tar as used in cosmetics.

PubMed

2008-01-01

Coal Tar is a semisolid by-product obtained in the destructive distillation of bituminous coal, which functions in cosmetic products as a cosmetic biocide and denaturant--antidandruff agent is also listed as a function, but this is considered an over-the-counter (OTC) drug use. Coal Tar is a nearly black, viscous liquid, heavier than water, with a naphthalene-like odor and a sharp burning taste, produced in cooking ovens as a by-product in the manufacture of coke. Crude Coal Tar is composed of 48% hydrocarbons, 42% carbon, and 10% water. In 2002, Coal Tar was reported to the Food and Drug Administration (FDA) to be used in four formulations, all of which appear to be OTC drug products. Coal Tar is monographed by the FDA as Category I (safe and effective) OTC drug ingredient for use in the treatment of dandruff, seborrhoea, and psoriasis. Coal Tar is absorbed through the skin of animals and humans and is systemically distributed. In short-term studies, mice fed a diet containing Coal Tar found it unpalatable, but no adverse effects were reported other than weight loss; rats injected with Coal Tar experienced malaise in one study and decreased water intake and increased liver weights in another; rabbits injected with Coal Tar residue experienced eating avoidance, respiratory difficulty, sneezing, and weight loss. In a subchronic neurotoxicity study using mice, a mixture of phenols, cresols, and xylenols at concentrations approximately equal to those expected in Coal Tar extracts produced regionally selective effects, with a rank order of corpus striatum > cerebellum > cerebral cortex. Coal Tar applied to the backs of guinea pigs increases epidermal thickness. Painting female rabbits with tar decreases the absolute and relative weights of the ovaries and decreased the number of interstitial cells in the ovary. Four therapeutic Coal Tar preparations used in the treatment of psoriasis were mutagenic in the Ames assay. Urine and blood from patients treated with Coal Tar

Smokers' knowledge and understanding of advertised tar numbers: health policy implications.

PubMed

Cohen, J B

1996-01-01

This article examines health policy implications of providing smokers with numerical tar yield information in cigarette advertising. Results of a national probability telephone survey regarding smokers' knowledge and understanding of numerical tar yields and deliveries are reported. Few smokers knew the tar level of their own cigarettes (the exception being smokers of 1- to 5-mg tar cigarettes), and a majority could not correctly judge the relative tar levels of cigarettes. Smokers were unsure whether switching to lower-tar cigarettes would reduce their personal health risks. Many smokers relied on absolute numbers in making trade-offs between number of cigarettes smoked and their tar levels, thus confusion machine-rated tar-yields with actual amounts ingested. The wisdom of the present method of providing tar and nicotine numbers in ads and recommendations for modifying the test protocol are now under discussion. This research indicates that these tar numbers and their implications are poorly understood. The paper recommends revisions in tar ratings to make them more useful and a required statement on cigarette packages to more explicitly relate tar levels to major health risks.

Improved detection and mapping of deepwater hydrocarbon seeps: optimizing multibeam echosounder seafloor backscatter acquisition and processing techniques

NASA Astrophysics Data System (ADS)

Mitchell, Garrett A.; Orange, Daniel L.; Gharib, Jamshid J.; Kennedy, Paul

2018-06-01

Marine seep hunting surveys are a current focus of hydrocarbon exploration surveys due to recent advances in offshore geophysical surveying, geochemical sampling, and analytical technologies. Hydrocarbon seeps are ephemeral, small, discrete, and therefore difficult to sample on the deep seafloor. Multibeam echosounders are an efficient seafloor exploration tool to remotely locate and map seep features. Geophysical signatures from hydrocarbon seeps are acoustically-evident in bathymetric, seafloor backscatter, midwater backscatter datasets. Interpretation of these signatures in backscatter datasets is a fundamental component of commercial seep hunting campaigns. Degradation of backscatter datasets resulting from environmental, geometric, and system noise can interfere with the detection and delineation of seeps. We present a relative backscatter intensity normalization method and an oversampling acquisition technique that can improve the geological resolvability of hydrocarbon seeps. We use Green Canyon (GC) Block 600 in the Northern Gulf of Mexico as a seep calibration site for a Kongsberg EM302 30 kHz MBES prior to the start of the Gigante seep hunting program to analyze these techniques. At GC600, we evaluate the results of a backscatter intensity normalization, assess the effectiveness of 2X seafloor coverage in resolving seep-related features in backscatter data, and determine the off-nadir detection limits of bubble plumes using the EM302. Incorporating these techniques into seep hunting surveys can improve the detectability and sampling of seafloor seeps.

7 CFR 3201.76 - Asphalt and tar removers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Asphalt and tar removers. 3201.76 Section 3201.76... Designated Items § 3201.76 Asphalt and tar removers. (a) Definition. Cleaning agents designed to remove asphalt or tar from equipment, roads, or other surfaces. (b) Minimum biobased content. The Federal...

7 CFR 3201.76 - Asphalt and tar removers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Asphalt and tar removers. 3201.76 Section 3201.76... Designated Items § 3201.76 Asphalt and tar removers. (a) Definition. Cleaning agents designed to remove asphalt or tar from equipment, roads, or other surfaces. (b) Minimum biobased content. The Federal...

Methanotrophic gastropods from a bathyal hydrocarbon seep, Gulf of Mexico

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

Anderson, L.C.; Aharon, P.; Gupta, S.

Two gastropods, Neritina sp. and Truncatella sp., collected live from a Gulf of Mexico active gas seep with the submersible Johnson Sea Link in September 1991, apparently incorporate methane-derived carbon in their soft tissues. Flesh of an individual Neritina sp. had a delta C-13 of [minus]50.92 per mil PDB, and that of two coexisting individuals of Truncatella sp. had values of [minus]45.11 and [minus]49.27 per mil. These isotope values are comparable to those reported for the methanotrophic mytilid bivalve Bathymodiolus sp. from other hydrocarbon seeps on the Gulf of Mexico, and are lighter than published isotopic values of chemosynthetic organismsmore » with sulfur-oxidizing symbionts. The anomalously light carbon-isotopic values of Neritina sp. and Truncatella sp. may steam from one of three causes: (1) these gastropods host symbiotic methanotrophic bacteria, (2) their chief food is methane-oxidizing bacteria present at the seep, or (3) they incorporate some carbon from the periostracum of mussels on which they may graze. The presence of abundant juveniles of Bathymodiolus, reported to settle preferentially in areas of active seepage and high methane release, indicates that methane was abundant and supported a community with multiple trophic levels. Generally, studies of hydrocarbon-seep communities have focused on larger community members, especially bivalves and tube worms. The presence of living Neritina and Truncatella at the authors sampling site, however, draws attention to the fact that these gastropods are integral and significant parts of hydrocarbon-seep communities. Both gastropod species are members of genera that characteristically inhabit shallow marine, intertidal, and semiterrestrial environments. The presence of these genera in bathyal hydrocarbon seeps indicates that they have very broad environmental ranges, thus limiting their utility in paleoecologic reconstructions.« less

Smokers' knowledge and understanding of advertised tar numbers: health policy implications.

PubMed Central

Cohen, J B

1996-01-01

OBJECTIVES. This article examines health policy implications of providing smokers with numerical tar yield information in cigarette advertising. METHODS. Results of a national probability telephone survey regarding smokers' knowledge and understanding of numerical tar yields and deliveries are reported. RESULTS. Few smokers knew the tar level of their own cigarettes (the exception being smokers of 1- to 5-mg tar cigarettes), and a majority could not correctly judge the relative tar levels of cigarettes. Smokers were unsure whether switching to lower-tar cigarettes would reduce their personal health risks. Many smokers relied on absolute numbers in making trade-offs between number of cigarettes smoked and their tar levels, thus confusion machine-rated tar-yields with actual amounts ingested. CONCLUSIONS. The wisdom of the present method of providing tar and nicotine numbers in ads and recommendations for modifying the test protocol are now under discussion. This research indicates that these tar numbers and their implications are poorly understood. The paper recommends revisions in tar ratings to make them more useful and a required statement on cigarette packages to more explicitly relate tar levels to major health risks. PMID:8561236

Discovery and Characterization of Cold Seep Vents Using a Mass Spectrometer Operating aboard an Autonomous Underwater Vehicle

NASA Astrophysics Data System (ADS)

Camilli, R.; Macelloni, L.; Asper, V.; Woolsey, M.; Williams, J.; Diercks, A.; Lutken, C. B.; Sleeper, K.

2009-12-01

A chemical and bathymetric survey was conducted in June 2009 at a known gas hydrate site approximately 900 meters deep in the Gulf of Mexico Mississippi Canyon 118 block. This survey used the EagleRay autonomous underwater vehicle equipped with a TETHYS in-situ mass spectrometer and EM 2000 multibeam sonar. Results indicate previously unobserved active sea floor methane seeps that correlate with bathymetric depressions and a geologic fault. These data suggest linkage of the methane cold seeps to an underlying thermogenic hydrocarbon reservoir.

The Australian tar derby: the origins and fate of a low tar harm reduction programme

PubMed Central

King, W; Carter, S; Borland, R; Chapman, S; Gray, N

2003-01-01

Objective: To document the development of the low tar harm reduction programme in Australia, including tobacco industry responses. Data sources: Tobacco industry documents, retail tobacco journals, newspapers, medical journals, and Anti-Cancer Council of Victoria (ACCV) newsletters and archival records. Study selection: Documents on the strategies and knowledge bases of the ACCV, other Australian health authorities, and the tobacco industry. Results: The ACCV built a durable system for measuring and publicising the tar and nicotine yields of Australian cigarettes and influencing their development. The tobacco industry initially sought to block the development of this system but later appeared to cooperate with it, as is evidenced by the current market dominance of low tar brands. However, behind the scenes, the industry used its substantial knowledge advantage regarding compensatory smoking and its ability to re-engineer cigarettes to gain effective control of the system and subvert the ACCV's objectives. Conclusions: Replacement of the low tar programme with new means of minimising the harms from cigarette smoking should be a policy priority for the Australian government. This will require regulation, rather than further voluntary agreements, and stringent monitoring of successor programmes will be necessary. PMID:14645950

A hydrothermal seep on the Costa Rica margin: middle ground in a continuum of reducing ecosystems

PubMed Central

Levin, Lisa A.; Orphan, Victoria J.; Rouse, Greg W.; Rathburn, Anthony E.; Ussler, William; Cook, Geoffrey S.; Goffredi, Shana K.; Perez, Elena M.; Waren, Anders; Grupe, Benjamin M.; Chadwick, Grayson; Strickrott, Bruce

2012-01-01

Upon their initial discovery, hydrothermal vents and methane seeps were considered to be related but distinct ecosystems, with different distributions, geomorphology, temperatures, geochemical properties and mostly different species. However, subsequently discovered vents and seep systems have blurred this distinction. Here, we report on a composite, hydrothermal seep ecosystem at a subducting seamount on the convergent Costa Rica margin that represents an intermediate between vent and seep ecosystems. Diffuse flow of shimmering, warm fluids with high methane concentrations supports a mixture of microbes, animal species, assemblages and trophic pathways with vent and seep affinities. Their coexistence reinforces the continuity of reducing environments and exemplifies a setting conducive to interactive evolution of vent and seep biota. PMID:22398162

Cold seeps associated with a submarine debris avalanche deposit at Kick'em Jenny volcano, Grenada (Lesser Antilles)

NASA Astrophysics Data System (ADS)

Carey, Steven; Ballard, Robert; Bell, Katherine L. C.; Bell, Richard J.; Connally, Patrick; Dondin, Frederic; Fuller, Sarah; Gobin, Judith; Miloslavich, Patricia; Phillips, Brennan; Roman, Chris; Seibel, Brad; Siu, Nam; Smart, Clara

2014-11-01

Remotely operated vehicle (ROV) exploration at the distal margins of a debris avalanche deposit from Kick'em Jenny submarine volcano in Grenada has revealed areas of cold seeps with chemosynthetic-based ecosystems. The seeps occur on steep slopes of deformed, unconsolidated hemipelagic sediments in water depths between 1952 and 2042 m. Two main areas consist of anastomosing systems of fluid flow that have incised local sediments by several tens of centimeters. No temperature anomalies were observed in the vent areas and no active flow was visually observed, suggesting that the venting may be waning. An Eh sensor deployed on a miniature autonomous plume recorder (MAPR) recorded a positive signal and the presence of live organisms indicates at least some venting is still occurring. The chemosynthetic-based ecosystem included giant mussels (Bathymodiolus sp.) with commensal polychaetes (Branchipolynoe sp.) and cocculinid epibionts, other bivalves, Siboglinida (vestimentiferan) tubeworms, other polychaetes, and shrimp, as well as associated heterotrophs, including gastropods, anemones, crabs, fish, octopods, brittle stars, and holothurians. The origin of the seeps may be related to fluid overpressure generated during the collapse of an ancestral Kick'em Jenny volcano. We suggest that deformation and burial of hemipelagic sediment at the front and base of the advancing debris avalanche led to fluid venting at the distal margin. Such deformation may be a common feature of marine avalanches in a variety of geological environments especially along continental margins, raising the possibility of creating large numbers of ephemeral seep-based ecosystems.

Skin cancer in patients with psoriasis treated with coal tar. A 25-year follow-up study

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

Pittelkow, M.R.; Perry, H.O.; Muller, S.A.

1981-08-01

For many years, crude coal tar has been used for the treatment of psoriasis. The possible carcinogenic effect of crude coal tar and ultraviolet (UV) radiation (Goeckerman regimen), considered individually or in combination, has been of some concern to physicians. A 25-year follow-up study was completed on 280 patients with psoriasis who were hospitalized and treated with crude coal tar and UV radiation at the Mayo Clinic, Rochester, Minn, during the years 1950 through 1954. The results of this study suggest that the incidence of skin cancer is not appreciably increased above the expected incidence for the general population whenmore » patients are treated with coal tar ointments. It seems that the Goeckerman regimen (topical crude coal tar combined with UV radiation) can be used with minimal risk for skin cancer in the treatment of psoriasis.« less

Influence of parasitism in controlling the health, reproduction and PAH body burden of petroleum seep mussels

NASA Astrophysics Data System (ADS)

Powell, Eric N.; Barber, Robert D.; Kennicutt, Mahlon C., II; Ford, Susan E.

1999-12-01

known to be sequestered preferentially in gametic tissue. Bucephalus would be expected to reduce overall body burden, at high infection intensities, by replacing gametic tissue. PAH concentrations exceeded 1 ppm in 4 of 9 populations, a ratio significantly higher than the 8 of 30 mussel locales in the NOAA Mussel Watch Program. Only five Mussel Watch locales exceeded the highest value for a petroleum seep population. Digestive gland and gill tissue atrophy were not significantly correlated with PAH body burden, even though some populations were characterized by body burdens exceeding 1 ppm, suggesting that seep mussels may not be as sensitive to PAH exposure as are some shallow-water mytilid populations.

Influence of cigarette filter ventilation on smokers' mouth level exposure to tar and nicotine.

PubMed

Caraway, John W; Ashley, Madeleine; Bowman, Sheri A; Chen, Peter; Errington, Graham; Prasad, Krishna; Nelson, Paul R; Shepperd, Christopher J; Fearon, Ian M

2017-12-01

Cigarette filter ventilation allows air to be drawn into the filter, diluting the cigarette smoke. Although machine smoking reveals that toxicant yields are reduced, it does not predict human yields. The objective of this study was to investigate the relationship between cigarette filter ventilation and mouth level exposure (MLE) to tar and nicotine in cigarette smokers. We collated and reviewed data from 11 studies across 9 countries, in studies performed between 2005 and 2013 which contained data on MLE from 156 products with filter ventilation between 0% and 87%. MLE among 7534 participants to tar and nicotine was estimated using the part-filter analysis method from spent filter tips. For each of the countries, MLE to tar and nicotine tended to decrease as filter ventilation increased. Across countries, per-cigarette MLE to tar and nicotine decreased as filter ventilation increased from 0% to 87%. Daily MLE to tar and nicotine also decreased across the range of increasing filter ventilation. These data suggest that on average smokers of highly ventilated cigarettes are exposed to lower amounts of nicotine and tar per cigarette and per day than smokers of cigarettes with lower levels of ventilation. Copyright © 2017 British American Tobacco. Published by Elsevier Inc. All rights reserved.

Submarine seep of carbon dioxide in Norton Sound, Alaska

USGS Publications Warehouse

Kvenvolden, K.A.; Weliky, K.; Nelson, H.; Des Marais, D.J.

1979-01-01

Earlier workers have described a submarine gas seep in Norton Sound having an unusual mixture of petroleum-like, low-molecular-weight hydrocarbons. Actually, only about 0.04 percent of the seeping gas is hydrocarbons and 98 percent is carbon dioxide. The isotopic compositions of carbon dioxide (??13CPDB = -2.7 per mil) and methane (??13CPDB = -36 per mil, where PDB is the Peedee belemnite standard) indicate that geothermal processes are active here. Copyright ?? 1979 AAAS.

Marine-controlled source electromagnetic study of methane seeps and gas hydrates at Opouawe Bank, Hikurangi Margin, New Zealand

NASA Astrophysics Data System (ADS)

Schwalenberg, Katrin; Rippe, Dennis; Koch, Stephanie; Scholl, Carsten

2017-05-01

Marine controlled source electromagnetic (CSEM) data have been collected to investigate methane seep sites and associated gas hydrate deposits at Opouawe Bank on the southern tip of the Hikurangi Margin, New Zealand. The bank is located in about 1000 m water depth within the gas hydrate stability field. The seep sites are characterized by active venting and typical methane seep fauna accompanied with patchy carbonate outcrops at the seafloor. Below the seeps, gas migration pathways reach from below the bottom-simulating reflector (at around 380 m sediment depth) toward the seafloor, indicating free gas transport into the shallow hydrate stability field. The CSEM data have been acquired with a seafloor-towed, electric multi-dipole system measuring the inline component of the electric field. CSEM data from three profiles have been analyzed by using 1-D and 2-D inversion techniques. High-resolution 2-D and 3-D multichannel seismic data have been collected in the same area. The electrical resistivity models show several zones of highly anomalous resistivities (>50 Ωm) which correlate with high amplitude reflections located on top of narrow vertical gas conduits, indicating the coexistence of free gas and gas hydrates within the hydrate stability zone. Away from the seeps the CSEM models show normal background resistivities between 1 and 2 Ωm. Archie's law has been applied to estimate gas/gas hydrate saturations below the seeps. At intermediate depths between 50 and 200 m below seafloor, saturations are between 40 and 80% and gas hydrate may be the dominating pore filling constituent. At shallow depths from 10 m to the seafloor, free gas dominates as seismic data and gas plumes suggest.

Morphology of Florida Escarpment chemosynthetic brine seep community sites

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

Paull, C.K.; Spiess, F.N.; Curray, J.R.

1988-01-01

The Florida Escarpment near 26/sup 0/N was surveyed with Deep-Two, Seabeam, and GLORIA in the area where chemosynthetic communities were discovered via ALVIN in the abyssal Gulf of Mexico. Seabeam bathymetry and GLORIA images indicate that the escarpment is a generally straight cliff with average slopes of about 45/sup 0/ from 2,200 to more than 3,250 m. The escarpment's face is cut by 2-km wide box canyons whose head walls are as steep as the intervening escarpment's face. The shapes of these canyons are difficult to explain with the traditional models of canyon formation. Sidescan sonar images and bottom photographsmore » reveal that the escarpment's face is composed of a series of long, straight bedding-plane terraces which are truncated along nearly vertical orthogonal joints. Exposure of these truncated strata indicate the face of the escarpment is eroded. The contact between the basal escarpment and the flat-lying abyssal hemipelagic sediments is abrupt. Apparently, chemosynthetic communities line extensive sections of the escarpment base where reduced brines seep out into the sea floor. The morphology suggests joints and deep seeps are controlling factors in scarp retreat.« less

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

NASA Astrophysics Data System (ADS)

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 (<1% total). The processes that control the concentration and isotopic signature of these gases in sediments are well explained for methane, but the controls for C2/C3 cycling are still a relative mystery. Methane production proceeds in deep anoxic sediments by either 1) thermocatalytic cracking of fossil organic matter, or 2) as a direct product of microbial metabolism, i.e. methanogenesis. In surface sediments, it appears that both microbial consumption and chemical deposition of methane (i.e. as methane clathrate) ensures that >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

Imaging hydrological processes in headwater riparian seeps with time-lapse electrical resistivity

USDA-ARS?s Scientific Manuscript database

The activation of subsurface seepage in response to precipitation events represents a potentially important pathway of nitrogen (N) delivery to streams in agricultural catchments. We used electrical resistivity imaging (ERI) and shallow piezometers to elucidate how seep and non-seep areas within the...

Cold seep-related occurrence of the Early Jurassic rhynchonellid brachiopod Anarhynchia from the Canadian Cordillera

NASA Astrophysics Data System (ADS)

Pálfy, József; Price, Gregory D.; Vörös, Attila; Kovács, Zsófia; Johannson, Gary G.

2017-04-01

Cold seeps, where seepage of methane and/or other hydrocarbon-rich fluids and hydrogen-sulfide occurs in the sea floor, are sites which harbor highly specialized ecosystems associated with distinctive carbonate sediments. Although their Mesozoic record is scarce and patchy, it commonly includes rhynchonellid brachiopods, often of large size. Each new occurrence is valuable in filling gaps and providing additional insight into these peculiar ecosystems. Here we report a monospecific assemblage of Anarhynchia from a boulder-sized limestone clast of Early Pliensbachian (Early Jurassic) age in the Inklin Formation of the Whitehorse Trough in Stikine terrane, recovered from a locality at Copper Island in Atlin Lake, northern British Columbia, Canada. Specimens are of unusually large size, up to 9 cm in length, and their external and internal morphology allows assignment to Anarhynchia but warrants introduction of a new species. Although d13C and d18O values of the shells are close to equilibrium with ancient seawater, early precipitated carbonate cement phases of the enclosing limestone are characterised by highly depleted carbon isotopic composition, indicative of the influence of microbial oxidation of methane derived from a cold seep. Carbonate petrography of the isopachous, banded-fibrous cement supports its origin in a cold seep environment. Volcanogenic detrital grains in the micritic matrix of the limestone clast are indistinguishable from those in the sandstone layers in the siliciclastic sequence, suggesting that the seep carbonate is broadly coeval with the enclosing conglomerate. Previously, Anarhynchia has been known from the Lower Jurassic of California and Oregon, from both cold seep and hydrothermal vent deposits. Our new record extends the geographic range and species-level diversity of the genus, but supports its endemism to the East Pacific and membership in chemosynthesis-based ecosystems.

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

NASA Astrophysics Data System (ADS)

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.

Microbial communities in methane seep sediments along US Atlantic Margin are structured by organic matter and seepage dynamics

NASA Astrophysics Data System (ADS)

Graw, M. F.; Pohlman, J.; Treude, T.; Ruppel, C. D.; Colwell, F. S.

2016-12-01

Methane seeps are dynamic environments on continental margins where subsurface methane reaches the ocean. Microbial communities play a critical role in carbon cycling within seep sediments via organic carbon degradation, methane production, and anaerobic oxidation of methane (AOM), which consumes 20-80% of methane in seep sediments. However, biogeochemical controls on microbial community structure at seeps on a margin-wide scale remain unclear. The passive US Atlantic Margin (USAM) has been identified as a region of active methane seepage. Passive margin seeps have traditionally been understudied relative to seeps on active margins. Passive margins exhibit large cross-margin variability in organic carbon deposition and are anticipated to have divergent seep dynamics from active margins. Thus, the USAM offers a unique opportunity to investigate controls on microbial communities in seep sediments. We undertook analysis of microbial communities inhabiting seep sediments at 6 biogeochemically distinct sites along the USAM. Microbiological samples were co-located with measurements of sediment geochemistry and AOM and sulfate reduction rates. Illumina sequencing of the 16S rRNA gene, using both universal (83 samples) and archaeal-specific (64 samples) primers, and the mcrA gene (18 samples) identified 44 bacterial phyla and 7 archaeal phyla. Seeps in canyons and on open slope, likely representing high and low organic content sediments, hosted distinct communities; the former was dominated by ammonia-oxidizing Marine Group I Thaumarchaeota and the latter by mixotrophic Hadesarchaeota. Seep stability also impacted microbial community structure, and in particular the establishment of an AOM community rather than a Bathyarchaeota-dominated community. These findings contribute to understanding how microbial communities are structured within methane seep sediments and pave the way for investigating broad differences in carbon cycling between seeps on passive and active margins.

Stable isotope trophic patterns in echinoderm megafauna in close proximity to and remote from Gulf of Mexico lower slope hydrocarbon seeps

NASA Astrophysics Data System (ADS)

Carney, Robert Spencer

2010-11-01

Hydrocarbon-seep communities in the Gulf of Mexico have a high biomass that is exploited as a food source to varying degrees by the photosynthesis-dependent fauna inhabiting the surrounding mud bottom. A decline concurrent with ocean depth in detritus influx to that background habitat results in a much lower background biomass. The biomass contrast between population-rich seeps and depauperate mud bottom leads to the prediction that seep utilization by the background fauna should be extensive at all depths and should increase with depth. Species depth zonation makes like-species comparisons over the full depth of the Gulf of Mexico impossible. Seeps and normal bottom above 1000 m have different fauna from those below 1000 m. Lower slope seeps are surrounded by a fauna rich in echinoderm species, especially asteroids, ophiuroids, and holothuroids. All three taxa have species that are abundant within seeps and are probably endemic to them. They also contain species found only in mud background or within mud and seeps backgrounds. Tissue analyses of δ13C and δ15N of echinoderms collected by ROV within seeps and trawling away from seeps indicate a pattern of utilization similar to that found in upper slope seeps exploited by different taxa. Seastar and ophiuroid species abundant in or endemic to seeps have tissue isotope values reflecting seep chemosynthetic input via a free-living microbial detritus or predation. A single seep-endemic deposit-feeding holothuroid showed distinct seep tissue values. Background deposit-feeding holothuroids collected within seeps showed either no or only minor incorporation of seep carbon, indicating either a lack of access to seep detritus or short feeding times within the seep. A predicted extensive utilization of seep productivity at the deeper seeps was not found. Seeps may be relatively closed systems that require special adaptations of species in order for them to enter, exploit, and survive. Alternately, the surrounding deep

Atmospheric tar balls from biomass burning in Mexico

NASA Astrophysics Data System (ADS)

Adachi, K.; Buseck, P. R.

2009-12-01

Tar balls are spherical, organic aerosol particles that result from biofuel or biomass burning. They absorb sunlight and cause warming of the atmosphere. Although distinctive when viewed with a transmission electron microscope (TEM) because of their spherical shape, much remains to be determined about details of their compositions, occurrences, and generation. Here we aim to characterize the occurrences of tar balls using individual-particle analyses with a TEM and to study their formation in young biomass-burning smoke. The samples were collected using the U.S. Forest Service Twin Otter aircraft during the MILAGRO (Megacity Initiative: Local and Global Research Observations) campaign conducted in March 2006. We analyzed 84 TEM grid samples from ~30 biomass-burning events near Mexico City and over Yucatan. Sixty samples were from young smoke (less than an hour old), and others were from haze that mainly occurred from biomass burning. Tar balls have neither an evident nucleus nor are they normally attached to other particles. They are almost perfectly spherical on TEM grids, indicating that they were solid when collected. It appears as if tar balls consist of lower volatility organic matter than many other organic aerosol particles. On average, 9% by number of biomass-burning aerosol particles were tar balls in samples collected between a few minutes to an hour after emission. On the other hand, samples collected within a few minutes after emission included few or no tar balls. The occurrences and abundances of atmospheric tar balls are important when evaluating the effects of smoke on local and regional climate.

Use of mineral oil Fleet enema for the removal of a large tar burn: a case report.

PubMed

Carta, Tricia; Gawaziuk, Justin; Liu, Song; Logsetty, Sarvesh

2015-03-01

Extensive hot tar burns are relatively uncommon. Management of these burns provides a significant clinical challenge especially with respect to tar removal involving a large total body surface area (TBSA), without causing further tissue injury. We report a case of an over 40-year old male construction worker who was removing a malfunctioning cap from broken valve. This resulted in tar spraying over the anterior surface of his body including legs, feet, chest, abdomen, arms, face and oral cavity (80% TBSA covered in tar resulting in a 50% TBSA burn injury). Initially, petrolatum-based, double antibiotic ointment was used to remove the tar, based on our previous experience with small tar burns. However, this was time-consuming and ineffective. The tar was easily removed with mineral oil without irritation. In order to meet the demand for quantity of mineral oil, the pharmacy suggested using mineral oil Fleet enema (C.B. Fleet Company, Inc., Lynchburg, Virginia, USA). The squeezable bottle and catheter tip facilitated administration of oil into the patient's construction boots and under clothing that was adhered to the patient's skin. Tar removal requires an effective, non-toxic and non-irritating agent. Mineral oil is such an agent. For patients that may present with a large surface area tar burn, using mineral oil Fleet enema is a viable option that facilitates application into difficult areas. Grant Support: The Firefighters' Burn Fund (Manitoba) supported this project. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Atmospheric Tar Balls: Particles from Biomass and Biofuel Burning

NASA Technical Reports Server (NTRS)

Posfai, Mihaly; Gelencser, Andras; Simonics, Renata; Arato, Krisztina; Li, Jia; Hobbs, Peter V.; Buseck, Peter R.

2004-01-01

Tar balls are amorphous, carbonaceous spherules that occur in the tropospheric aerosol as a result of biomass and biofuel burning. They form a distinct group of particles with diameters typically between 30 and 500 nm and readily identifiable with electron microscopy. Their lack of a turbostratic microstructure distinguishes them from soot, and their morphology and composition (approximately 90 mol% carbon) renders them distinct from other carbonaceous particles. Tar balls are particularly abundant in slightly aged (minutes to hours old) biomass smoke, indicating that they likely form by gas-to-particle conversion within smoke plumes. The material of tar balls is initially hygroscopic; however, the particles become largely insoluble as a result of free radical polymerization of their organic molecules. Consequently, tar balls are primarily externally mixed with other particle types, and they do not appreciably increase in size during aging. When tar balls coagulate with water-bearing particles, their material may partly dissolve and no longer be recognizable as distinct particles. Tar balls may contain organic compounds that absorb sunlight. They are an important, previously unrecognized type of carbonaceous (organic) atmospheric particle.

Investigating Hydrocarbon Seep Environments with High-Resolution, Three-Dimensional Geographic Visualizations.

NASA Astrophysics Data System (ADS)

Doolittle, D. F.; Gharib, J. J.; Mitchell, G. A.

2015-12-01

Detailed photographic imagery and bathymetric maps of the seafloor acquired by deep submergence vehicles such as Autonomous Underwater Vehicles (AUV) and Remotely Operated Vehicles (ROV) are expanding how scientists and the public view and ultimately understand the seafloor and the processes that modify it. Several recently acquired optical and acoustic datasets, collected during ECOGIG (Ecosystem Impacts of Oil and Gas Inputs to the Gulf) and other Gulf of Mexico expeditions using the National Institute for Undersea Science Technology (NIUST) Eagle Ray, and Mola Mola AUVs, have been fused with lower resolution data to create unique three-dimensional geovisualizations. Included in these data are multi-scale and multi-resolution visualizations over hydrocarbon seeps and seep related features. Resolution of the data range from 10s of mm to 10s of m. When multi-resolution data is integrated into a single three-dimensional visual environment, new insights into seafloor and seep processes can be obtained from the intuitive nature of three-dimensional data exploration. We provide examples and demonstrate how integration of multibeam bathymetry, seafloor backscatter data, sub-bottom profiler data, textured photomosaics, and hull-mounted multibeam acoustic midwater imagery are made into a series a three-dimensional geovisualizations of actively seeping sites and associated chemosynthetic communities. From these combined and merged datasets, insights on seep community structure, morphology, ecology, fluid migration dynamics, and process geomorphology can be investigated from new spatial perspectives. Such datasets also promote valuable inter-comparisons of sensor resolution and performance.

Detection of Natural Oil Seeps in the Atlantic Ocean Using MODIS

NASA Technical Reports Server (NTRS)

Reahard, Ross; Jones, Jason B.; Mitchell, Mark

2010-01-01

Natural oil seepage is the release of crude oil into the ocean from fissures in the seabed. Oil seepage is a major contributor to the total amount of oil entering the world s oceans. According to a 2003 study by the National Academy of Sciences (NAS), 47 percent of oil entering the world s oceans is from natural seeps, and 53 percent is from human sources (extraction, transportation, and consumption). Oil seeps cause smooth oil slicks to form on the water s surface. Oil seeps can indicate the location of stores of fossil fuel beneath the ocean floor. Knowledge of the effect of oil seepage on marine life and marine ecosystems remains limited. In the past, remote sensing has been used to detect oil seeps in the Gulf of Mexico and off of the coast of southern California. This project utilized sun glint MODIS imagery to locate oil slicks off of the Atlantic coast, an area that had not previously been surveyed for natural oil seeps using remote sensing. Since 1982, the Atlantic Ocean has been closed to any oil and gas drilling. Recently, however, the U.S. Minerals Management Services (MMS) has proposed a lease for oil and gas drilling off the coasts of Virginia and North Carolina. Determining the location of seepage sites in the Atlantic Ocean will help MMS locate potential deposits of oil and natural gas, thereby reducing the risk of leasing areas for petroleum extraction that do not contain these natural resources.

Seep and stream nitrogen dynamics in two adjacent mixed land use watersheds

USDA-ARS?s Scientific Manuscript database

In many headwater catchments, streamflow originates from surface seeps and springs. The objective of this study was to determine the influence of seeps on nitrogen (N) dynamics within the stream and at the outlet of two adjacent mixed land use watersheds. Nitrogen concentrations in stream water were...

Tar, nicotine, and carbon monoxide yields of some Nigerian cigarettes.

PubMed Central

Awotedu, A A; Higenbottam, T W; Onadeko, B O

1983-01-01

Fourteen cigarette brands manufactured in Nigeria in 1981 were analysed to determine the tar, nicotine, and carbon monoxide yields. Five of the brands belonged to the high and middle to high tar category (greater than 22 mg/cigarette) and nine to the middle tar (17-22 mg/cigarette) category. None of the cigarettes was in the low to middle and low tar (less than 17 mg/cigarette) category. The nicotine and carbon monoxide yields were similar to those of European cigarettes. Tobacco companies need to manufacture low tar cigarettes in the Third World as is the practice in the economically developed parts of the world. PMID:6619721

Method and apparatus for hydrocarbon recovery from tar sands

DOEpatents

Westhoff, J.D.; Harak, A.E.

1988-05-04

A method and apparatus for utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000/degree/F in a burner to remove residual char and produce a solid waste that is easily disposable. The process and apparatus have the advantages of being able to utilize tar sands having a broad range of bitumen content and the advantage of producing product gases that are free from combustion gases and thereby have a higher heating value. Another important advantage is rapid pyrolysis of the tar sands in the cyclone so as to effectively utilize smaller sized reactor vessels for reducing capitol and operating costs. 1 fig., 1 tab.

Method and apparatus for hydrocarbon recovery from tar sands

DOEpatents

Westhoff, James D.; Harak, Arnold E.

1989-01-01

A method and apparatus for utilizing tar sands having a broad range of bitumen content is disclosed. More particularly, tar sands are pyrolyzed in a cyclone retort with high temperature gases recycled from the cyclone retort to produce oil and hydrocarbon products. The spent tar sands are then burned at 2000.degree. F. in a burner to remove residual char and produce a solid waste that is easily disposable. The process and apparatus have the advantages of being able to utilize tar sands having a broad range of bitumen content and the advantage of producing product gases that are free from combustion gases and thereby have a higher heating value. Another important advantage is rapid pyrolysis of the tar sands in the cyclone so as to effectively utilize smaller sized reactor vessels for reducing capitol and operating costs.

Catchment-scale variation in the nitrate concentrations of groundwater seeps in the Catskill Mountains, New York, U.S.A.

USGS Publications Warehouse

West, A.J.; Findlay, S.E.G.; Burns, Douglas A.; Weathers, K.C.; Lovett, Gary M.

2001-01-01

Forested headwater streams in the Catskill Mountains of New York show significant among-catchment variability in mean annual nitrate (NO3-) concentrations. Large contributions from deep groundwater with high NO3- concentrations have been invoked to explain high NO3- concentrations in stream water during the growing season. To determine whether variable contributions of groundwater could explain among-catchment differences in streamwater, we measured NO3- concentrations in 58 groundwater seeps distributed across six catchments known to have different annual average streamwater concentrations. Seeps were identified based on release from bedrock fractures and bedding planes and had consistently lower temperatures than adjacent streamwaters. Nitrate concentrations in seeps ranged from near detection limits (0.005 mg NO3--N/L) to 0.75 mg NO3--N/L. Within individual catchments, groundwater residence time does not seem to strongly affect NO3- concentrations because in three out of four catchments there were non-significant correlations between seep silica (SiO2) concentrations, a proxy for residence time, and seep NO3- concentrations. Across catchments, there was a significant but weak negative relationship between NO3- and SiO2 concentrations. The large range in NO3- concentrations of seeps across catchments suggests: 1) the principal process generating among-catchment differences in streamwater NO3- concentrations must influence water before it enters the groundwater flow system and 2) this process must act at large spatial scales because among-catchment variability is much greater than intra-catchment variability. Differences in the quantity of groundwater contribution to stream baseflow are not sufficient to account for differences in streamwater NO3- concentrations among catchments in the Catskill Mountains.

Seep and stream nitrogen dynamics in two adjacent mixed land use watersheds

USDA-ARS?s Scientific Manuscript database

In many headwater catchments, stream flow originates from surface seeps and springs. The objective of this study was to determine the influence of seeps on nitrogen (N) dynamics within the stream and at the outlet of two adjacent mixed land use watersheds. Nitrogen concentrations in stream water wer...

Gas flux and carbonate occurrence at a shallow seep of thermogenic natural gas

NASA Astrophysics Data System (ADS)

Kinnaman, Franklin S.; Kimball, Justine B.; Busso, Luis; Birgel, Daniel; Ding, Haibing; Hinrichs, Kai-Uwe; Valentine, David L.

2010-06-01

The Coal Oil Point seep field located offshore Santa Barbara, CA, consists of dozens of named seeps, including a peripheral ˜200 m2 area known as Brian Seep, located in 10 m water depth. A single comprehensive survey of gas flux at Brian Seep yielded a methane release rate of ˜450 moles of CH4 per day, originating from 68 persistent gas vents and 23 intermittent vents, with gas flux among persistent vents displaying a log normal frequency distribution. A subsequent series of 33 repeat surveys conducted over a period of 6 months tracked eight persistent vents, and revealed substantial temporal variability in gas venting, with flux from each individual vent varying by more than a factor of 4. During wintertime surveys sediment was largely absent from the site, and carbonate concretions were exposed at the seafloor. The presence of the carbonates was unexpected, as the thermogenic seep gas contains 6.7% CO2, which should act to dissolve carbonates. The average δ13C of the carbonates was -29.2 ± 2.8‰ VPDB, compared to a range of -1.0 to +7.8‰ for CO2 in the seep gas, indicating that CO2 from the seep gas is quantitatively not as important as 13C-depleted bicarbonate derived from methane oxidation. Methane, with a δ13C of approximately -43‰, is oxidized and the resulting inorganic carbon precipitates as high-magnesium calcite and other carbonate minerals. This finding is supported by 13C-depleted biomarkers typically associated with anaerobic methanotrophic archaea and their bacterial syntrophic partners in the carbonates (lipid biomarker δ13C ranged from -84 to -25‰). The inconsistency in δ13C between the carbonates and the seeping CO2 was resolved by discovering pockets of gas trapped near the base of the sediment column with δ13C-CO2 values ranging from -26.9 to -11.6‰. A mechanism of carbonate formation is proposed in which carbonates form near the sediment-bedrock interface during times of sufficient sediment coverage, in which anaerobic oxidation

Hydrothermal vents and methane seeps: Rethinking the sphere of influence

USGS Publications Warehouse

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

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

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

Eric M. Suuberg; Vahur Oja

1997-07-01

This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization whichmore » have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.« less

Petroleum surface oil seeps from Palaeoproterozoic petrified giant oilfield

NASA Astrophysics Data System (ADS)

Melezhik, V.; Fallick, A.; Filippov, M.; Lepland, A.; Rychanchik, D.; Deines, Yu.; Medvedev, P.; Romashkin, A.; Strauss, H.

2009-04-01

Evidence of petroleum generation and migration has been previously reported from rocks dating as early as 3.25 Ga. Micron-size carbonaceous streaks and bitumen micronodules were found in abundance in Archaean rocks across the Pilbara craton in Australia suggesting pervasive petroleum generation and migration. However, none of the Archaean petroleum deposits has been reported to be preserved in quantity due to destructive effects of deformation and thermal obliteration during metamorphism. During the Palaeoproterozoic, unprecedented accumulation of Corg-rich rocks worldwide, known as the 2.0 Ga Shunga Event, occurred during the early stage of progressive oxidation of terrestrial environments, and in the aftermath of the Lomagundi-Jatuli isotopic event, which based on the magnitude and duration of positive d13C was the greatest perturbation of the global carbon cycle in Earth history. C. 2.0 Ga Zaonezhskaya Formation (ZF) rocks from the Onega Basin in Russian Fennoscandia contain evidence for substantial accumulation and preservation of organic matter (up to 75 wt.-% total organic carbon) with an estimated original petroleum potential comparable to a modern supergiant oilfield. The basin contains a uniquely preserved petrified oilfield including evidence of oil traps and oil migration pathways. Here, we report the discovery of the surface expression of a migration pathway, along which petroleum was flowing from the sub-surface. This surface oil seep, the first occurrence ever reported from the Palaeoproterozoic, appears as originally bitumen clasts redeposited in Palaeoproterozoic lacustrine turbidites of the Kondopozhskaya Formation. The d13Corg of clastic pyrobitumen ranges between -35.4 and -36.0 per mill (n = 14) which is within the range of interbed- and vein-trapped fossil oil (-46 and -24 per mill), suggesting similar source. Biogenic organic matter, whose isotopic composition was modified during thermal maturation, is the likely source for the migrated

Exosomes from HIV-1-infected Cells Stimulate Production of Pro-inflammatory Cytokines through Trans-activating Response (TAR) RNA*

PubMed Central

Sampey, Gavin C.; Saifuddin, Mohammed; Schwab, Angela; Barclay, Robert; Punya, Shreya; Chung, Myung-Chul; Hakami, Ramin M.; Asad Zadeh, Mohammad; Lepene, Benjamin; Klase, Zachary A.; El-Hage, Nazira; Young, Mary; Iordanskiy, Sergey; Kashanchi, Fatah

2016-01-01

HIV-1 infection results in a chronic illness because long-term highly active antiretroviral therapy can lower viral titers to an undetectable level. However, discontinuation of therapy rapidly increases virus burden. Moreover, patients under highly active antiretroviral therapy frequently develop various metabolic disorders, neurocognitive abnormalities, and cardiovascular diseases. We have previously shown that exosomes containing trans-activating response (TAR) element RNA enhance susceptibility of undifferentiated naive cells to HIV-1 infection. This study indicates that exosomes from HIV-1-infected primary cells are highly abundant with TAR RNA as detected by RT-real time PCR. Interestingly, up to a million copies of TAR RNA/μl were also detected in the serum from HIV-1-infected humanized mice suggesting that TAR RNA may be stable in vivo. Incubation of exosomes from HIV-1-infected cells with primary macrophages resulted in a dramatic increase of proinflammatory cytokines, IL-6 and TNF-β, indicating that exosomes containing TAR RNA could play a direct role in control of cytokine gene expression. The intact TAR molecule was able to bind to PKR and TLR3 effectively, whereas the 5′ and 3′ stems (TAR microRNAs) bound best to TLR7 and -8 and none to PKR. Binding of TAR to PKR did not result in its phosphorylation, and therefore, TAR may be a dominant negative decoy molecule in cells. The TLR binding through either TAR RNA or TAR microRNA potentially can activate the NF-κB pathway and regulate cytokine expression. Collectively, these results imply that exosomes containing TAR RNA could directly affect the proinflammatory cytokine gene expression and may explain a possible mechanism of inflammation observed in HIV-1-infected patients under cART. PMID:26553869

Treating tar sands formations with dolomite

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael

2010-06-08

Methods for treating a tar sands formation are described herein. The tar sands formation may include dolomite and hydrocarbons. Methods may include providing heat at less than the decomposition temperature of dolomite from one or more heaters to at least a portion of the formation. At least some of the hydrocarbon fluids are mobilized in the formation. At least some of the hydrocarbon fluids may be produced from the formation.

[Methanotrophic bacteria in cold seeps of the floodplains of northern rivers].

PubMed

Belova, S É; Oshkin, I Iu; Glagolev, M V; Lapshina, E D; Maksiutov, Sh Sh; Dedysh, S N

2013-01-01

Small mud volcanoes (cold seeps), which are common in the floodplains of northern rivers, are a potentially important, although poorly studied sources of atmospheric methane. Field research on the cold seeps of the Mukhrina River (Khanty-Mansiysk Autonomous okrug, Russia) revealed methane fluxes from these structures to be orders of magnitude higher than from equivalent areas of the mid-taiga bogs. Microbial communities developing around the seeps were formed under conditions of high methane concentrations, low temperatures (3-5 degrees C), and near-neutral pH. Molecular identification of methane-oxidizing bacteria from this community by analysis of the pmoA gene encoding particulate methane monooxygenase revealed both type I and type II methanotrophs (classes Gammaproteobacteria and Alphaproteobacteria, respectively), with predomination of type I methanotrophs. Among the latter, microorganisms related to Methylobacterpsychrophilus and Methylobacter tundripaludum, Crenothrix polyspora (a stagnant water dweller), and a number of methanotrophs belonging to unknown taxa were detected. Growth characteristics of two isolates were determined. Methylobactersp. CMS7 exhibited active growth at 4-10 degrees C, while Methylocystis sp. SB12 grew better at 20 degrees C. Experimental results confirmed the major role ofmethanotrophic gammaproteobacteria in controlling the methane emission from cold river seeps.

Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

PubMed

Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

2016-11-15

The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. Copyright © 2016 Elsevier B.V. All rights reserved.

A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas

PubMed Central

2016-01-01

Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported. PMID:27974524

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

PubMed Central

Lee, On On; Wang, Yong; Tian, Renmao; Zhang, Weipeng; Shek, Chun Shum; Bougouffa, Salim; Al-Suwailem, Abdulaziz; Batang, Zenon B.; Xu, Wei; Wang, Guang Chao; Zhang, Xixiang; Lafi, Feras F.; Bajic, Vladmir B.; Qian, Pei-Yuan

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. PMID:24399144

Quantification of methane fluxes from hydrocarbon seeps to the ocean and atmosphere: Development of an in situ and online gas flux measuring system

NASA Astrophysics Data System (ADS)

Di, Pengfei; Chen, Qinghua; Chen, Duofu

2017-06-01

Natural hydrocarbon seeps in the marine environment are important contributors to greenhouse gases in the atmosphere. Such gases include methane, which plays a significant role in global carbon cycling and climate change. To accurately quantify the methane flux from hydrocarbon seeps on the seafloor, a specialized in situ and online gas flux measuring (GFM) device was designed to obtain high-resolution time course gas fluxes using the process of equal volume exchange. The device consists of a 1.0-m diameter, 0.9-m tall, inverted conical tent and a GFM instrument that contains a solenoid valve, level transducer, and gas collection chamber. Rising gas bubbles from seeps were measured by laboratory-calibrated GFM instruments attached to the top of the tent. According to the experimental data, the optimal anti-shake time interval was 5 s. The measurement range of the device was 0-15 L min-1, and the relative error was ± 1.0%. The device was initially deployed at an active seep site in the Lingtou Promontory seep field in South China Sea. The amount of gas released from a single gas vent was 30.5 m3 during the measurement period, and the gas flow rate ranged from 22 to 72 L h-1, depending on tidal period, and was strongly negatively correlated with water depth. The measurement results strongly suggest that oceanic tides and swells had a significant forcing effect on gas flux. Low flow rates were associated with high tides and vice versa. The changes in gas volume escaping from the seafloor seeps could be attributed to the hydrostatic pressure induced by water depth. Our findings suggest that in the marine environment, especially in the shallow shelf area, sea level variation may play an important role in controlling methane release into the ocean. Such releases probably also affect atmospheric methane levels.

Fractal-like Tar Ball Aggregates from Wildfire Smoke

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

Girotto, Giulia; China, Swarup; Bhandari, Janarjan

Tar balls are atmospheric particles abundant in slightly aged biomass burning smoke and have a significant, but highly uncertain, role on Earth's radiative balance. Tar balls are typically detected using electron microscopy; they are resistant to the electron beam, and generally, they are observed as individual spheres. Here, we report new observations of a significant fraction of tar ball aggregates (~27% by number) from samples collected in a plume of the Whitewater-Baldy Complex fire in New Mexico. The structure of these aggregates is fractal-like and follows a scale invariant power law similar to that of soot particles, despite the considerablymore » larger size and smaller number of monomers. We also present observations of tar ball aggregates from four other geographical locations, including from a remote high elevation site in the North Atlantic Ocean. Aggregation affects the particle optical properties and therefore, their climatic impact. We performed numerical simulations based on the observed morphology and estimated the effects of aggregation on the tar balls optical properties. We find that aggregation can enhance single scattering albedo by up to 41%.« less

Study on tar generated from downdraft gasification of oil palm fronds.

PubMed

Atnaw, Samson Mekbib; Kueh, Soo Chuan; Sulaiman, Shaharin Anwar

2014-01-01

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study.

Study on Tar Generated from Downdraft Gasification of Oil Palm Fronds

PubMed Central

Atnaw, Samson Mekbib; Kueh, Soo Chuan; Sulaiman, Shaharin Anwar

2014-01-01

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study. PMID:24526899

Sydney Tar Ponds Remediation: Experience to China

ERIC Educational Resources Information Center

Liu, Fan; Bryson, Ken A.

2009-01-01

The infamous "Sydney Tar Ponds" are well known as one of the largest toxic waste sites of Canada, due to almost 100 years of steelmaking in Sydney, a once beautiful and peaceful city located on the east side of Cape Breton Island, Nova Scotia. This article begins with a contextual overview of the Tar Ponds issue including a brief…

Identification of sources of tar balls deposited along the Goa coast, India, using fingerprinting techniques.

PubMed

Suneel, V; Vethamony, P; Zakaria, M P; Naik, B G; Prasad, K V S R

2013-05-15

Deposition of tar balls along the coast of Goa, India is a common phenomenon during the southwest monsoon. Representative tar ball samples collected from various beaches of Goa and one Bombay High (BH) crude oil sample were subjected to fingerprint analysis based on diagnostic ratios of n-alkane, biomarkers of pentacyclic tri-terpanes and compound specific stable carbon isotope (δ¹³C) analysis to confirm the source. The results were compared with the published data of Middle East Crude Oil (MECO) and South East Asian Crude Oil (SEACO). The results revealed that the tar balls were from tanker-wash derived spills. The study also confirmed that the source is not the BH, but SEACO. The present study suggests that the biomarkers of alkanes and hopanes coupled with stable carbon isotope analysis act as a powerful tool for tracing the source of tar balls, particularly when the source specific biomarkers fail to distinguish the source. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quantifying Nitrogen Transport from Riparian Groundwater Seeps to a Headwater Stream in an Agricultural Watershed

NASA Astrophysics Data System (ADS)

Redder, B.; Buda, A. R.; Kennedy, C. D.; Folmar, G.; DeWalle, D. R.; Boyer, E. W.

2017-12-01

Headwater streams in the Northeast region of the United States typically receive more than 50% of their base flow from groundwater, either by diffuse discharge through the streambed or by localized discharge through riparian seeps. It is very difficult to separate the individual contributions of these two groundwater fluxes to streamflow. Furthermore, riparian seeps show significant variability in discharge and nutrient concentration, adding uncertainty to estimates of groundwater-based nitrogen inputs to streams. In this study, we combined stream measurements at two different scales to quantify groundwater discharge by matrix flow through the streambed and by macropore flow through the riparian zone. The study site was a 175-m stream reach located in a heavily cultivated 45-hectare watershed in east-central Pennsylvania. Differential streamflow gauging and streambed measurements of hydraulic head gradient, hydraulic conductivity, and groundwater chemistry were used to solve for the riparian groundwater flux in a reach mass balance equation. Adopting a mass balance approach, riparian groundwater fluxes ranged from 115-205 m3 d-1, transporting 2-4 kg N d-1 of nitrate from the fractured bedrock aquifer to the stream. Air-water manometer readings from short-screened piezometers installed in the shallow streambed (30 cm) indicated slightly losing head gradients between the stream and groundwater, despite substantial (36-66%) increases in stream flow along the stream reach. Preliminary chemical data for the stream, streambed, and shallow ground water suggest that the stream is partially disconnected from the underlying aquifer and that riparian groundwater seeps supply essentially all water and nitrogen to the system. These results, along with the comparison of shallow and deep aquifer water with seep chemistry, provide insight into sources of water to riparian groundwater seeps and allow us to determine the transport and fate of nitrogen in a fractured aquifer system

Temporal variability of submarine groundwater discharge: Assessments via radon and seep meters, the southern carmel coast, Israel

USGS Publications Warehouse

Weinstein, Y.; Shalem, Y.; Burnett, W.C.; Swarzenski, P.W.; Herut, B.

2007-01-01

Seep meter data from Dor Bay, Israel, showed a steady decrease in submarine groundwater discharge (SGD) rates between March and July 2006 (averages of 34, 10.4 and 1.5 cm d-1 in March, May and July, respectively), while estimates based on radon time series showed remarkably uniform averages (8 cm d-1). The May seep meter data show a rough positive correlation with sea level, unlike the negative correlation shown by the Rn-calculated rates. Smaller-size meters, deployed in July adjacent to the regular-size ones, showed significantly higher rates (10 cm d-1), which negatively correlated with salinity. It is suggested that the decreased rates documented by the seep meters are the result of an increased shallow seawater recharge in the bay (due to decreasing hydraulic gradients). This is not captured by the radon, since recharging water is radon-poor. The positive correlation of discharge with sea level is due to increased seawater recycling in times of high sea stand. Copyright ?? 2007 IAHS Press.

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

NASA Astrophysics Data System (ADS)

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

Human immunodeficiency virus type 1 LTR TATA and TAR region sequences required for transcriptional regulation.

PubMed Central

Garcia, J A; Harrich, D; Soultanakis, E; Wu, F; Mitsuyasu, R; Gaynor, R B

1989-01-01

The human immunodeficiency virus (HIV) type 1 LTR is regulated at the transcriptional level by both cellular and viral proteins. Using HeLa cell extracts, multiple regions of the HIV LTR were found to serve as binding sites for cellular proteins. An untranslated region binding protein UBP-1 has been purified and fractions containing this protein bind to both the TAR and TATA regions. To investigate the role of cellular proteins binding to both the TATA and TAR regions and their potential interaction with other HIV DNA binding proteins, oligonucleotide-directed mutagenesis of both these regions was performed followed by DNase I footprinting and transient expression assays. In the TATA region, two direct repeats TC/AAGC/AT/AGCTGC surround the TATA sequence. Mutagenesis of both of these direct repeats or of the TATA sequence interrupted binding over the TATA region on the coding strand, but only a mutation of the TATA sequence affected in vivo assays for tat-activation. In addition to TAR serving as the site of binding of cellular proteins, RNA transcribed from TAR is capable of forming a stable stem-loop structure. To determine the relative importance of DNA binding proteins as compared to secondary structure, oligonucleotide-directed mutations in the TAR region were studied. Local mutations that disrupted either the stem or loop structure were defective in gene expression. However, compensatory mutations which restored base pairing in the stem resulted in complete tat-activation. This indicated a significant role for the stem-loop structure in HIV gene expression. To determine the role of TAR binding proteins, mutations were constructed which extensively changed the primary structure of the TAR region, yet left stem base pairing, stem energy and the loop sequence intact. These mutations resulted in decreased protein binding to TAR DNA and defects in tat-activation, and revealed factor binding specifically to the loop DNA sequence. Further mutagenesis which inverted

Microbial iron redox cycling in a circumneutral-pH groundwater seep.

PubMed

Blöthe, Marco; Roden, Eric E

2009-01-01

The potential for microbially mediated redox cycling of iron (Fe) in a circumneutral-pH groundwater seep in north central Alabama was studied. Incubation of freshly collected seep material under anoxic conditions with acetate-lactate or H(2) as an electron donor revealed the potential for rapid Fe(III) oxide reduction (ca. 700 to 2,000 micromol liter(-1) day(-1)). Fe(III) reduction at lower but significant rates took place in unamended controls (ca. 300 micromol liter(-1) day(-1)). Culture-based enumerations (most probable numbers [MPNs]) revealed significant numbers (10(2) to 10(6) cells ml(-1)) of organic carbon- and H(2)-oxidizing dissimilatory Fe(III)-reducing microorganisms. Three isolates with the ability to reduce Fe(III) oxides by dissimilatory or fermentative metabolism were obtained (Geobacter sp. strain IST-3, Shewanella sp. strain IST-21, and Bacillus sp. strain IST-38). MPN analysis also revealed the presence of microaerophilic Fe(II)-oxidizing microorganisms (10(3) to 10(5) cells ml(-1)). A 16S rRNA gene library from the iron seep was dominated by representatives of the Betaproteobacteria including Gallionella, Leptothrix, and Comamonas species. Aerobic Fe(II)-oxidizing Comamonas sp. strain IST-3 was isolated. The 16S rRNA gene sequence of this organism is 100% similar to the type strain of the betaproteobacterium Comamonas testosteroni (M11224). Testing of the type strain showed no Fe(II) oxidation. Collectively our results suggest that active microbial Fe redox cycling occurred within this habitat and support previous conceptual models for how microbial Fe oxidation and reduction can be coupled in surface and subsurface sedimentary environments.

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

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Metagenomic analysis of microbial consortium from natural crude oil that seeps into the marine ecosystem offshore Southern California

PubMed Central

Hawley, Erik R.; Piao, Hailan; Scott, Nicole M.; Malfatti, Stephanie; Pagani, Ioanna; Huntemann, Marcel; Chen, Amy; Glavina del Rio, Tijana; Foster, Brian; Copeland, Alex; Jansson, Janet; Pati, Amrita; Tringe, Susannah; Gilbert, Jack A.; Lorenson, Thomas D.; Hess, Matthias

2014-01-01

Crude oils can be major contaminants of the marine ecosystem and microorganisms play a significant role in the degradation of its main constituents. To increase our understanding of the microbial hydrocarbon degradation process in the marine ecosystem, we collected crude oil from an active seep area located in the Santa Barbara Channel (SBC) and generated a total of about 52 Gb of raw metagenomic sequence data. The assembled data comprised ~500 Mb, representing ~1.1 million genes derived primarily from chemolithoautotrophic bacteria. Members of Oceanospirillales, a bacterial order belonging to the Deltaproteobacteria, recruited less than 2% of the assembled genes within the SBC metagenome. In contrast, the microbial community associated with the oil plume that developed in the aftermath of the Deepwater Horizon (DWH) blowout in 2010, was dominated by Oceanospirillales, which comprised more than 60% of the metagenomic data generated from the DWH oil plume. This suggests that Oceanospirillales might play a less significant role in the microbially mediated hydrocarbon conversion within the SBC seep oil compared to the DWH plume oil. We hypothesize that this difference results from the SBC oil seep being mostly anaerobic, while the DWH oil plume is aerobic. Within the Archaea, the phylum Euryarchaeota, recruited more than 95% of the assembled archaeal sequences from the SBC oil seep metagenome, with more than 50% of the sequences assigned to members of the orders Methanomicrobiales and Methanosarcinales. These orders contain organisms capable of anaerobic methanogenesis and methane oxidation (AOM) and we hypothesize that these orders – and their metabolic capabilities – may be fundamental to the ecology of the SBC oil seep. PMID:25197496

Metagenomic analysis of microbial consortium from natural crude oil that seeps into the marine ecosystem offshore Southern California

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

Hawley, Erik R.; Piao, Hailan; Scott, Nicole M.

2014-01-02

Crude oils can be major contaminants of the marine ecosystem and microorganisms play a significant role in the degradation of the main constituents of crude oil. To increase our understanding of the microbial hydrocarbon degradation process in the marine ecosystem, we collected crude oil from an active seep area located in the Santa Barbara Channel (SBC) and generated a total of about 52 Gb of raw metagenomic sequence data. The assembled data comprised ~500 Mb, representing ~1.1 million genes derived primarily from chemolithoautotrophic bacteria. Members of Oceanospirillales, a bacterial order belonging to the Deltaproteobacteria, recruited less than 2% of themore » assembled genes within the SBC metagenome. In contrast, the microbial community associated with the oil plume that developed in the aftermath of the Deepwater Horizon (DWH) blowout in 2010, was dominated by Oceanospirillales, which comprised more than 60% of the metagenomic data generated from the DWH oil plume. This suggests that Oceanospirillales might play a less significant role in the microbially mediated hydrocarbon conversion within the SBC seep oil compared to the DWH plume oil. We hypothesize that this difference results from the SBC oil seep being mostly anaerobic, while the DWH oil plume is aerobic. Within the Archaea, the phylum Euryarchaeota, recruited more than 95% of the assembled archaeal sequences from the SBC oil seep metagenome, with more than 50% of the sequences assigned to members of the orders Methanomicrobiales and Methanosarcinales. These orders contain organisms capable of anaerobic methanogenesis and methane oxidation (AOM) and we hypothesize that these orders and their metabolic capabilities may be fundamental to the ecology of the SBC oil seep.« less

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

NASA Astrophysics Data System (ADS)

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 (<5 wt%) of dolomite are present in most samples. Petrographically, Mg-calcite peloidal matrix and acicular to botryoidal aragonitic void-filling cements are the most frequent associations. The carbon isotopic compositions of the carbonates range from -60.8 to 14.0‰ PDB, indicating complex carbon sources that include 13C-depleted biogenic and thermogenic methane, biodegraded crude 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

Colonization of over a thousand Cibicidoides wuellerstorfi (foraminifera: Schwager, 1866) on artificial substrates in seep and adjacent off-seep locations in dysoxic, deep-sea environments

NASA Astrophysics Data System (ADS)

Burkett, Ashley M.; Rathburn, Anthony E.; Elena Pérez, M.; Levin, Lisa A.; Martin, Jonathan B.

2016-11-01

After ~1 yr on the seafloor at water depths of ~700 m on Hydrate Ridge in the Pacific, eight colonization experiments composed primarily of a plastic mesh cube (from here on refered to as SEA3, for Seafloor Epibenthic Attachment Cubes) were colonized by 1076 Cibicidoides wuellerstorfi on ~1841 cm2 of experimental substrate. This species is typically considered an indicator of well-oxygenated conditions, and recruitment of such large numbers in bottom waters with low dissolved oxygen availability (0.24-0.37 mL/L) indicate that this taxon may not be as limited by oxygen as previously thought. Clues about substrate preferences were evident from the distribution, or lack thereof, of individuals among plastic mesh, coated steel frame, wooden dowels and reflective tape. Abundance, individual size distributions within cage populations and isotopic biogeochemistry of living foraminifera colonizing experimental substrates were compared between active seep and adjacent off-seep experiment locations, revealing potential differences between these environments. Few studies have examined foraminiferal colonization of hard substrates in the deep-sea and to our knowledge no previous study has compared foraminiferal colonization of active seep and off-seep substrates from the same region. This study provides initial results of recruitment, colonization, geochemical and morphological aspects of the paleoceanographically significant species, C. wuellerstorfi, from dynamic deep-sea environments. Further experimental deployments of SEA3s will provide a means to assess relatively unknown ecologic dynamics of important foraminiferal deep-sea species.

48 CFR Appendix to Part 1252 - Tar Matrix

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Tar Matrix Appendix to Part 1252 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Pt. 1252, App. Appendix to Part 1252—Tar Matrix ER27DE05.000...

Integrated Biomass Gasification with Catalytic Partial Oxidation for Selective Tar Conversion

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

Zhang, Lingzhi; Wei, Wei; Manke, Jeff

Biomass gasification is a flexible and efficient way of utilizing widely available domestic renewable resources. Syngas from biomass has the potential for biofuels production, which will enhance energy security and environmental benefits. Additionally, with the successful development of low Btu fuel engines (e.g. GE Jenbacher engines), syngas from biomass can be efficiently used for power/heat co-generation. However, biomass gasification has not been widely commercialized because of a number of technical/economic issues related to gasifier design and syngas cleanup. Biomass gasification, due to its scale limitation, cannot afford to use pure oxygen as the gasification agent that used in coal gasification.more » Because, it uses air instead of oxygen, the biomass gasification temperature is much lower than well-understood coal gasification. The low temperature leads to a lot of tar formation and the tar can gum up the downstream equipment. Thus, the biomass gasification tar removal is a critical technology challenge for all types of biomass gasifiers. This USDA/DOE funded program (award number: DE-FG36-O8GO18085) aims to develop an advanced catalytic tar conversion system that can economically and efficiently convert tar into useful light gases (such as syngas) for downstream fuel synthesis or power generation. This program has been executed by GE Global Research in Irvine, CA, in collaboration with Professor Lanny Schmidt's group at the University of Minnesota (UoMn). Biomass gasification produces a raw syngas stream containing H2, CO, CO2, H2O, CH4 and other hydrocarbons, tars, char, and ash. Tars are defined as organic compounds that are condensable at room temperature and are assumed to be largely aromatic. Downstream units in biomass gasification such as gas engine, turbine or fuel synthesis reactors require stringent control in syngas quality, especially tar content to avoid plugging (gum) of downstream equipment. Tar- and ash-free syngas streams are a

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

PubMed

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.

Applications of multi-frequency single beam sonar fisheries analysis methods for seep quantification and characterization

NASA Astrophysics Data System (ADS)

Price, V.; Weber, T.; Jerram, K.; Doucet, M.

2016-12-01

The analysis of multi-frequency, narrow-band single-beam acoustic data for fisheries applications has long been established, with methodology focusing on characterizing targets in the water column by utilizing complex algorithms and false-color time series data to create and compare frequency response curves for dissimilar biological groups. These methods were built on concepts developed for multi-frequency analysis of satellite imagery for terrestrial analysis and have been applied to a broad range of data types and applications. Single-beam systems operating at multiple frequencies are also used for the detection and identification of seeps in water column data. Here we incorporate the same analysis and visualization techniques used for fisheries applications to attempt to characterize and quantify seeps by creating and comparing frequency response curves and applying false coloration to shallow and deep multi-channel seep data. From this information, we can establish methods to differentiate bubble size in the echogram and differentiate seep composition. These techniques are also useful in differentiating plume content from biological noise (volume reverberation) created by euphausid layers and fish with gas-filled swim bladders. The combining of the multiple frequencies using false coloring and other image analysis techniques after applying established normalization and beam pattern correction algorithms is a novel approach to quantitatively describing seeps. Further, this information could be paired with geological models, backscatter, and bathymetry data to assess seep distribution.

Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria

PubMed Central

Bailey, Jake V; Salman, Verena; Rouse, Gregory W; Schulz-Vogt, Heide N; Levin, Lisa A; Orphan, Victoria J

2011-01-01

We present evidence for a dimorphic life cycle in the vacuolate sulfide-oxidizing bacteria that appears to involve the attachment of a spherical Thiomargarita-like cell to the exteriors of invertebrate integuments and other benthic substrates at methane seeps. The attached cell elongates to produce a stalk-like form before budding off spherical daughter cells resembling free-living Thiomargarita that are abundant in surrounding sulfidic seep sediments. The relationship between the attached parent cell and free-living daughter cell is reminiscent of the dimorphic life modes of the prosthecate Alphaproteobacteria, but on a grand scale, with individual elongate cells reaching nearly a millimeter in length. Abundant growth of attached Thiomargarita-like bacteria on the integuments of gastropods and other seep fauna provides not only a novel ecological niche for these giant bacteria, but also for animals that may benefit from epibiont colonization. PMID:21697959

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

NASA Astrophysics Data System (ADS)

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.

Banded TARs in Iapygia

NASA Image and Video Library

2014-09-10

The tropics of Mars are commonly littered with small bright ripples that were somehow shaped by the wind. NASA Mars Reconnaissance Orbiter might provide a valuable clue to the formation of transverse aeolian ridges TARs elsewhere on Mars.

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

PubMed Central

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

2015-01-01

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. 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 subsurface-surface interactions

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

PubMed

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.

Determination of the conformational ensemble of the TAR RNA by X-ray scattering interferometry

PubMed Central

Walker, Peter

2017-01-01

Abstract The conformational ensembles of structured RNA's are crucial for biological function, but they remain difficult to elucidate experimentally. We demonstrate with HIV-1 TAR RNA that X-ray scattering interferometry (XSI) can be used to determine RNA conformational ensembles. X-ray scattering interferometry (XSI) is based on site-specifically labeling RNA with pairs of heavy atom probes, and precisely measuring the distribution of inter-probe distances that arise from a heterogeneous mixture of RNA solution structures. We show that the XSI-based model of the TAR RNA ensemble closely resembles an independent model derived from NMR-RDC data. Further, we show how the TAR RNA ensemble changes shape at different salt concentrations. Finally, we demonstrate that a single hybrid model of the TAR RNA ensemble simultaneously fits both the XSI and NMR-RDC data set and show that XSI can be combined with NMR-RDC to further improve the quality of the determined ensemble. The results suggest that XSI-RNA will be a powerful approach for characterizing the solution conformational ensembles of RNAs and RNA-protein complexes under diverse solution conditions. PMID:28108663

Determination of the conformational ensemble of the TAR RNA by X-ray scattering interferometry.

PubMed

Shi, Xuesong; Walker, Peter; Harbury, Pehr B; Herschlag, Daniel

2017-05-05

The conformational ensembles of structured RNA's are crucial for biological function, but they remain difficult to elucidate experimentally. We demonstrate with HIV-1 TAR RNA that X-ray scattering interferometry (XSI) can be used to determine RNA conformational ensembles. X-ray scattering interferometry (XSI) is based on site-specifically labeling RNA with pairs of heavy atom probes, and precisely measuring the distribution of inter-probe distances that arise from a heterogeneous mixture of RNA solution structures. We show that the XSI-based model of the TAR RNA ensemble closely resembles an independent model derived from NMR-RDC data. Further, we show how the TAR RNA ensemble changes shape at different salt concentrations. Finally, we demonstrate that a single hybrid model of the TAR RNA ensemble simultaneously fits both the XSI and NMR-RDC data set and show that XSI can be combined with NMR-RDC to further improve the quality of the determined ensemble. The results suggest that XSI-RNA will be a powerful approach for characterizing the solution conformational ensembles of RNAs and RNA-protein complexes under diverse solution conditions. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

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

NASA Astrophysics Data System (ADS)

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

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

PubMed Central

Woycheese, Kristin M.; Meyer-Dombard, D'Arcy R.; Cardace, Dawn; Argayosa, Anacleto M.; Arcilla, Carlo A.

2015-01-01

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 (DIC) (<0.5 ppm). Influx of atmospheric carbon dioxide (CO2) 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. PMID:25745416

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

PubMed

Woycheese, Kristin M; Meyer-Dombard, D'Arcy R; Cardace, Dawn; Argayosa, Anacleto M; Arcilla, Carlo A

2015-01-01

In the Zambales ophiolite range, terrestrial serpentinizing fluid seeps host diverse microbial assemblages. The fluids fall within the profile of Ca(2+)-OH(-)-type waters, indicative of active serpentinization, and are low in dissolved inorganic carbon (DIC) (<0.5 ppm). Influx of atmospheric carbon dioxide (CO2) 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.

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

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

Wiguna, Taufan, E-mail: taufan.wiguna@bppt.go.id; Ardhyastuti, Sri

2015-09-30

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 bymore » 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.« less

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 6 2013-07-01 2013-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 6 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 6 2011-07-01 2011-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 6 2012-07-01 2012-07-01 false Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

29 CFR 1910.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 6 2014-07-01 2013-07-01 true Coal tar pitch volatiles; interpretation of term. 1910.1002... Hazardous Substances § 1910.1002 Coal tar pitch volatiles; interpretation of term. As used in § 1910.1000 (Table Z-1), coal tar pitch volatiles include the fused polycyclic hydrocarbons which volatilize from the...

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

NASA Astrophysics Data System (ADS)

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

Coal tar-containing asphalt - resource or hazardous waste?

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

Andersson-Skold, Y.; Andersson, K.; Lind, B.

2007-09-30

Coal tar was used in Sweden for the production of asphalt and for the drenching of stabilization gravel until 1973. The tar has high concentrations of polycyclic aromatic hydrocarbons (PAH), some of which may be strongly carcinogenic. Approximately 20 million tonnes of tar-containing asphalt is present in the public roads in Sweden. Used asphalt from rebuilding can be classified as hazardous waste according to the Swedish Waste Act. The cost of treating the material removed as hazardous waste can be very high due to the large amount that has to be treated, and the total environmental benefit is unclear. Themore » transport of used asphalt to landfill or combustion will affect other environmental targets. The present project, based on three case studies of road projects in Sweden, evaluates the consequences of four scenarios for handling the material: reuse, landfill, biological treatment, and incineration. The results show that reuse of the coal tar-containing materials in new road construction is the most favorable alternative in terms of cost, material use, land use, energy consumption, and air emissions.« less

Polycyclic aromatic hydrocarbon (PAHs) and hopanes in stranded tar-balls on the coasts of Peninsular Malaysia: applications of biomarkers for identifying sources of oil pollution.

PubMed

Zakaria, M P; Okuda, T; Takada, H

2001-12-01

Malaysian coasts are subjected to various threats of petroleum pollution including routine and accidental oil spill from tankers, spillage of crude oils from inland and off-shore oil fields, and run-off from land-based human activities. Due to its strategic location, the Straits of Malacca serves as a major shipping lane. This paper expands the utility of biomarker compounds, hopanes, in identifying the source of tar-balls stranded on Malaysian coasts. 20 tar-ball samples collected from the east and west coast were analyzed for hopanes and polycyclic aromatic hydrocarbons (PAHs). Four of the 13 tar-ball samples collected from the west coast of Peninsular Malaysia were identified as the Middle East crude oil (MECO) based on their biomarker signatures, suggesting tanker-derived sources significantly contributing the petroleum pollution in the Straits of Malacca. The tar-balls found on the east coast seem to originate from the offshore oil platforms in the South China Sea. The presence of South East Asian crude oil (SEACO) tar-balls on the west coast carry several plausible explanations. Some of the tar-balls could have been transported via sea currents from the east coast. The tankers carrying SEACO to other countries could have accidentally spilt the oil as well. Furthermore, discharge of tank washings and ballast water from the tankers were suggested based on the abundance in higher molecular weight n-alkanes and the absence of unresolved complex mixture (UCM) in the tar-ball samples. The other possibilities are that the tar-balls may have been originated from the Sumatran oil fields and spillage of domestic oil from oil refineries in Port Dickson and Malacca. The results of PAHs analysis suggest that all the tar-ball samples have undergone various extent of weathering through evaporation, dissolution and photooxidation.

From the Belly of the Beast: Biogeochemistry and geomicrobiology of a fluid seep at Chimaera [Yanartas], Turkey

NASA Astrophysics Data System (ADS)

Woycheese, K. M.; Yargicoglu, E. N.; Cardace, D.; Meyer-Dombard, D. R.

2012-12-01

increased 13C enrichment with distance from the source in both Corg and CT. δ15N becomes more positive with distance from the source, and does not suggest active nitrogen fixation along the outflow channel. Scanning electron microscopy (SEM) equipped with X-ray energy dispersive spectroscopy (XEDS) and X-ray diffraction (XRD) confirms that the biomineralized microbial mats are primarily composed of carbonates. Microbial samples were collected for cultivation, phylogenetic and function-based DNA analysis. Samples will be screened for methanotrophy, C fixation, and N cycling. Successful cultures have been obtained from Yanartas samples, demonstrating growth on a wide variety of carbon substrates (e.g. organic acids, yeast extract, peptone, and sugars). This is the first report of biofilms and surface fluids associated with serpentinization at the Yanartas seep. 1. McCollom, T.M. & W. Bach (2009) GCA. 73(3): 856-875 2. Etiope, G.; Schoell, M. & H. Hosgörmez (2011) EPSL. 310: 96-104 3. de Boer, J.Z.; Chanton, J. & M. Zeitlhöfler (2007) Geowissenshaftliche. 158(4): 997-1003 4. Hosgörmez, H. (2007) J Asian Earth Sci. 30: 131-141

Hydrocarbon gas seeps of the convergent Hikurangi margin, North Island, New Zealand

USGS Publications Warehouse

Kvenvolden, K.A.; Pettinga, J.R.

1989-01-01

Two hydrocarbon gas seeps, located about 13 km apart, have distinctive molecular and isotopic compositions. These seeps occur within separate tectonic melange units of narrow parallel trending and structurally complex zones with incorporated upper Cretaceous and Palaeogene passive continental margin deposits which are now compressively deformed and imbricated along the convergent Hikurangi margin of North Island, New Zealand. At Brookby Station within the Coastal High, the seeping hydrocarbon gas has a methane/ethane ratio of 48 and ??13C and ??D values of methane of -45.7 and -188???, respectively (relative to the PDB and SMOW standards). Within the complex core of the Elsthorpe Anticline at Campbell Station seep, gas has a methane/ethane ratio of about 12000, and the methane has ??13C and ??D values of -37.4 and -170???, respectively. The source of the gases cannot be positively identified, but the gases probably originate from the thermal decomposition of organic matter in tectonically disturbed upper Cretaceous and/or lower Tertiary sedimentary rocks of passive margin affinity and reach the surface by migration along thrust faults associated with tectonic melange. The geochemical differences between the two gases may result from differences in burial depths of similar source sediment. ?? 1989.

The Importance of Chemosynthetic Communities and 'Seep-Hunting' to Deepwater Oil and Gas Exploration

NASA Astrophysics Data System (ADS)

McConnell, D.; Gharib, J. J.; Orange, D.; Henderson, J.; Danque, H.; Digby, A.

2007-12-01

Seafloor surveying techniques have often evolved as the industry's needs have evolved. Oil and gas exploration costs have escalated over the last several years, both as a result of increasing offshore overhead costs as well as the increased demand being met by offshore service-related companies. Consequently, more companies are prospecting using inexpensive techniques that rely on scientific expertise, such as seep-hunting, as a means of identifying reservoirs, and the past few years have seen several large-scale industrial deepwater surveys with locating hydrocarbon seeps as a primary goal. The identification of seeps is also a necessity for many pre-drilling operations, as many potential developers must conform to local regulations protecting chemosynthetic communities (eg MMS NTL 2000-G20 for Gulf of Mexico development). In addition to identifying chemosynthetic communities for permitting issues, as prospecting has moved into deeper water the ability to identify seep-related drilling hazards, such as hardgrounds or shallow gas (and hydrates) has also increased in importance. The specialized field of identifying seeps, and related chemosynthetics, hardgrounds, etc., is rapidly growing, aided by advances in mapping technology, such as multibeam backscatter and interferometry, among others. Today all of the geophysical data can be brought into a common interpretation environment providing multiple perspectives, different data overlays, and/or 3D visualizations. Using these techniques, high resolution multibeam and/or side-scan surveys rapidly cover large swaths of seafloor and identify potential seeps in real- time. These targets can then be examined geochemically with a coring program, potentially working simultaneously with the multibeam program. Modern USBL navigation can position a deepwater core in <10m diameter targets. Much of the geochemistry can be analyzed in near-real time at sea (eg headspace/interstitial gas, trace/minor/major ions in porefluids, etc

Examining the diversity and distribution of microbial communities from newly discovered methane seeps along the Cascadia Margin

NASA Astrophysics Data System (ADS)

Seabrook, S.; Thurber, A. R.; Embley, R. W.; Raineault, N.; Baumberger, T.; Merle, S. G.

2016-12-01

Methane seeps provide biogeochemical and microbial heterogeneity in deep-sea habitats. In June of 2016 the E/V Nautilus, exploring for methane seeps along the Cascadia continental margin, discovered over 450 bubble streams, indicative of active seepage, and collected biological samples at 6 of the resulting newly discovered seeps. These seeps covered a range of depths, latitudes, habitat types and biogeochemical environments and included: Juan de Fuca (150m), Astoria canyon (800m and 500m), Nehalem Bank (185m), Heceta SW (1200m), SW Coquille Bank (600m), and Klamath Knoll seep (700m). Geologic environment types included continental shelf, canyons and slopes, and these sites spanned the zone of hydrate stability and the Oxygen Minimum Zone. A range of seep-specific habitat were found and sampled including: reduced sediments, microbial mats, methane hydrates, clam beds (Calyptogena spp.), Siboglinidae tubeworm assemblages and sparse assemblages of stalked barnacles. Here, we present an initial characterization of the microbial communities collected via push cores by a remotely operated vehicle (ROV) at the six aforementioned sites. With high throughput amplicon sequencing of the V4-V5 region of the 16S rRNA gene, we characterize the diversity and microbial composition of the seep sites sampled. This characterization is furthered with digital drop PCR of the pmoA gene (involved with aerobic methanotrophy) to allow for a comparison of the community composition with functional gene abundance of critical microbial processes. These data will be placed in the greater biogeochemical context of the region, including direct comparison with paired gas-tight sampling at key locations. The results of these analyses will provide the first microbial description of this broad range of seep ecosystems along the Cascadia Margin adding to our overall understanding of microbial diversity, the dominant physiological processes at seep ecosystems, and the connection between community

Transformation-associated recombination (TAR) cloning for genomics studies and synthetic biology

PubMed Central

Kouprina, Natalay; Larionov, Vladimir

2016-01-01

Transformation-associated recombination (TAR) cloning represents a unique tool for isolation and manipulation of large DNA molecules. The technique exploits a high level of homologous recombination in the yeast Sacharomyces cerevisiae. So far, TAR cloning is the only method available to selectively recover chromosomal segments up to 300 kb in length from complex and simple genomes. In addition, TAR cloning allows the assembly and cloning of entire microbe genomes up to several Mb as well as engineering of large metabolic pathways. In this review, we summarize applications of TAR cloning for functional/structural genomics and synthetic biology. PMID:27116033

Anaerobic oxidation of methane in the Concepción Methane Seep Area, Chilean continental margin

NASA Astrophysics Data System (ADS)

Steeb, P.; Linke, P.; Scholz, F.; Schmidt, M.; Liebetrau, V.; Treude, T.

2012-04-01

carbonate blocks and plates hint to a very old seep system with a probably much higher activity in the past. The U-Th age record of these authigenic carbonates reach back to periods of venting activity with more than 150 ka ago. Carbon isotopic signatures of authigenic carbonates (δ13C -50 to -40‰ PDB) suggest a biogenic carbon source (i.e. methane), also in the past. We found several indications for the impact of recent earthquakes within the seep area (cracks, shifted seafloor), which could be an important mechanism for the triggering of new seepage activity, change in fluid expulsion rates and colonization patterns of the cold seep fauna.

Interpretation of the Relationship between Benthic Fauna, Geologic Distributions, and Methane Seeps at Southern Hydrate Ridge, Oregon Continental Margin

NASA Astrophysics Data System (ADS)

Bigham, K.; Kelley, D. S.; Delaney, J. R.

2016-12-01

Deposits of methane sequestered along continental margins and their associated seeps are found worldwide. These seeps are of increasing interest and importance because of their potential as an energy source, their contribution to greenhouse gases, and the unique community of chemosynthetic microorganisms and fauna that they host. One of the best­studied methane seep sites is Southern Hydrate Ridge, which is at a water depth of 800 m. It is located 90 km west of Newport, Oregon. Despite extensive geophysical and biological research completed here, no studies have quantified the relationship of seep sites and seafloor geology to the spatial distribution and abundances of microbial and macrofaunal communities. High resolution, georeferenced photomosaics of the individual seeps and the associated biological communities at this site were collected in 2011, using the remotely operated vehicle ROPOS. Detailed analyses of these images has allowed for the quantification and characterization of the diversity and structure of the faunal community. Results show that both the distribution and abundances of seep organisms are highly variable. Further examination of these photomosaics may improve understanding of the relationships between faunal distributions and seep locations, with implications for the impacts that chemical gradients have on these ecosystems.

Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis

PubMed Central

van den Bogaard, Ellen H.; Bergboer, Judith G.M.; Vonk-Bergers, Mieke; van Vlijmen-Willems, Ivonne M.J.J.; Hato, Stanleyson V.; van der Valk, Pieter G.M.; Schröder, Jens Michael; Joosten, Irma; Zeeuwen, Patrick L.J.M.; Schalkwijk, Joost

2013-01-01

Topical application of coal tar is one of the oldest therapies for atopic dermatitis (AD), a T helper 2 (Th2) lymphocyte–mediated skin disease associated with loss-of-function mutations in the skin barrier gene, filaggrin (FLG). Despite its longstanding clinical use and efficacy, the molecular mechanism of coal tar therapy is unknown. Using organotypic skin models with primary keratinocytes from AD patients and controls, we found that coal tar activated the aryl hydrocarbon receptor (AHR), resulting in induction of epidermal differentiation. AHR knockdown by siRNA completely abrogated this effect. Coal tar restored filaggrin expression in FLG-haploinsufficient keratinocytes to wild-type levels, and counteracted Th2 cytokine–mediated downregulation of skin barrier proteins. In AD patients, coal tar completely restored expression of major skin barrier proteins, including filaggrin. Using organotypic skin models stimulated with Th2 cytokines IL-4 and IL-13, we found coal tar to diminish spongiosis, apoptosis, and CCL26 expression, all AD hallmarks. Coal tar interfered with Th2 cytokine signaling via dephosphorylation of STAT6, most likely due to AHR-regulated activation of the NRF2 antioxidative stress pathway. The therapeutic effect of AHR activation herein described opens a new avenue to reconsider AHR as a pharmacological target and could lead to the development of mechanism-based drugs for AD. PMID:23348739

Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis.

PubMed

van den Bogaard, Ellen H; Bergboer, Judith G M; Vonk-Bergers, Mieke; van Vlijmen-Willems, Ivonne M J J; Hato, Stanleyson V; van der Valk, Pieter G M; Schröder, Jens Michael; Joosten, Irma; Zeeuwen, Patrick L J M; Schalkwijk, Joost

2013-02-01

Topical application of coal tar is one of the oldest therapies for atopic dermatitis (AD), a T helper 2 (Th2) lymphocyte-mediated skin disease associated with loss-of-function mutations in the skin barrier gene, filaggrin (FLG). Despite its longstanding clinical use and efficacy, the molecular mechanism of coal tar therapy is unknown. Using organotypic skin models with primary keratinocytes from AD patients and controls, we found that coal tar activated the aryl hydrocarbon receptor (AHR), resulting in induction of epidermal differentiation. AHR knockdown by siRNA completely abrogated this effect. Coal tar restored filaggrin expression in FLG-haploinsufficient keratinocytes to wild-type levels, and counteracted Th2 cytokine-mediated downregulation of skin barrier proteins. In AD patients, coal tar completely restored expression of major skin barrier proteins, including filaggrin. Using organotypic skin models stimulated with Th2 cytokines IL-4 and IL-13, we found coal tar to diminish spongiosis, apoptosis, and CCL26 expression, all AD hallmarks. Coal tar interfered with Th2 cytokine signaling via dephosphorylation of STAT6, most likely due to AHR-regulated activation of the NRF2 antioxidative stress pathway. The therapeutic effect of AHR activation herein described opens a new avenue to reconsider AHR as a pharmacological target and could lead to the development of mechanism-based drugs for AD.

Sampling of tar from sewage sludge gasification using solid phase adsorption.

PubMed

Ortiz González, Isabel; Pérez Pastor, Rosa Ma; Sánchez Hervás, José Ma

2012-06-01

Sewage sludge is a residue from wastewater treatment plants which is considered to be harmful to the environment and all living organisms. Gasification technology is a potential source of renewable energy that converts the sewage sludge into gases that can be used to generate energy or as raw material in chemical synthesis processes. But tar produced during gasification is one of the problems for the implementation of the gasification technology. Tar can condense on pipes and filters and may cause blockage and corrosion in the engines and turbines. Consequently, to minimize tar content in syngas, the ability to quantify tar levels in process streams is essential. The aim of this work was to develop an accurate tar sampling and analysis methodology using solid phase adsorption (SPA) in order to apply it to tar sampling from sewage sludge gasification gases. Four types of commercial SPA cartridges have been tested to determine the most suitable one for the sampling of individual tar compounds in such streams. Afterwards, the capacity, breakthrough volume and sample stability of the Supelclean™ ENVI-Carb/NH(2), which is identified as the most suitable, have been determined. Basically, no significant influences from water, H(2)S or NH(3) were detected. The cartridge was used in sampling real samples, and comparable results were obtained with the present and traditional methods.

A case-control study of asphalt and tar exposure and lung cancer in minorities.

PubMed

McClean, Michael D; Kelsey, Karl T; Sison, Jennette D; Quesenberry, Charles P; Wrensch, Margaret R; Wiencke, John K

2011-11-01

Considerable controversy surrounds the carcinogenic potential of asphalt and tar. Since minority individuals may have had relatively high historical exposures, we investigated asphalt and tar exposure and lung cancer risk among African Americans and Latino Americans. We conducted a case-control study of lung cancer among African Americans and Latino Americans in the San Francisco Bay area (422 cases, 894 controls). A questionnaire was used to obtain detailed work histories and exposure information. Self-reported exposure to asphalt and tar as well as other factors (e.g., smoking, automobile exhaust, and asbestos) were evaluated as predictors of lung cancer risk. Potential effect modification by cytochrome P450 (CYP) 1A1 was also explored. Self-reported duration of exposure to asphalt and tar was associated with a statistically significant excess risk of lung cancer in the overall population (OR: 1.11, 95% CI: 1.01-1.22), evaluating risk per year of exposure. Years of exposure to automobile exhaust (OR: 1.02, 95% CI: 1.00-1.05) and asbestos (OR: 1.04, 95% CI: 1.02-1.06) were also associated with statistically significant elevations in risk. In Latino Americans, the lung cancer risks associated with polycyclic aromatic hydrocarbon-related exposures were consistently higher in the CYP1A1 wild-type subjects as compared to the variant genotype subjects, and the interaction was statistically significant for smoking and the CYP1A1 M2 polymorphism (P-value(interaction) = 0.02). These data are consistent with the literature suggesting that exposure to asphalt and tar may increase risk of lung cancer. However, it was not possible to separate the effects and asphalt and tar in this study. Copyright © 2011 Wiley Periodicals, Inc.

A Case-Control Study of Asphalt and Tar Exposure and Lung Cancer in Minorities

PubMed Central

McClean, Michael D.; Kelsey, Karl T.; Sison, Jennette D; Quesenberry, Charles P; Wrensch, Margaret R; Wiencke, John K.

2011-01-01

Objectives Considerable controversy surrounds the carcinogenic potential of asphalt and tar. Since minority individuals may have had relatively high historical exposures, we investigated asphalt and tar exposure and lung cancer risk among African Americans and Latino Americans. Methods We conducted a case-control study of lung cancer among African Americans and Latino Americans in the San Francisco Bay area (422 cases, 894 controls). A questionnaire was used to obtain detailed work histories and exposure information. Self-reported exposure to asphalt and tar as well as other factors (eg. smoking, automobile exhaust, and asbestos) were evaluated as predictors of lung cancer risk. Potential effect modification by cytochrome P450 (CYP) 1A1 was also explored. Results Self-reported duration of exposure to asphalt and tar was associated with a statistically significant excess risk of lung cancer in the overall population (OR: 1.11, 95%CI: 1.01–1.22), evaluating risk per year of exposure. Years of exposure to automobile exhaust (OR: 1.02, 95%CI: 1.00–1.05) and asbestos (OR: 1.04, 95%CI: 1.02–1.06) were also associated with statistically significant elevations in risk. In Latino Americans, the lung cancer risks associated with polycyclic aromatic hydrocarbon-related exposures were consistently higher in the CYP1A1 wildtype subjects as compared to the variant genotype subjects, and the interaction was statistically significant for smoking and the CYP1A1 M2 polymorphism (p-valueinteraction=0.02). Conclusions These data are consistent with the literature suggesting that exposure to asphalt and tar may increase risk of lung cancer. However, it was not possible to separate the effects and asphalt and tar in this study. PMID:21882217

Probing interaction of a fluorescent ligand with HIV TAR RNA

NASA Astrophysics Data System (ADS)

Qi, Liang; Zhang, Jing; He, Tian; Huo, Yuan; Zhang, Zhi-Qi

2017-02-01

Trans-activator of Transcription (Tat) antagonists could block the interaction between Tat protein and its target, trans-activation responsive region (TAR) RNA, to inhibit Tat function and prevent human immunodeficiency virus type 1 (HIV-1) replication. For the first time, a small fluorescence ligand, ICR 191, was found to interact with TAR RNA at the Tat binding site and compete with Tat. It was also observed that the fluorescence of ICR 191 could be quenched when binding to TAR RNA and recovered when discharged via competition with Tat peptide or a well-known Tat inhibitor, neomycin B. The binding parameters of ICR 191 to TAR RNA were determined through theoretical calculations. Mass spectrometry, circular dichroism and molecular docking were used to further confirm the interaction of ICR 191 with TAR RNA. Inspired by these discoveries, a primary fluorescence model for the discovery of Tat antagonists was built using ICR 191 as a fluorescence indicator and the feasibility of this model was evaluated. This ligand-RNA interaction could provide a new strategy for research aimed at discovering Tat antagonists.

Thermocatalytic treatment of biomass tar model compounds via radio frequency.

PubMed

Anis, Samsudin; Zainal, Z A; Bakar, M Z A

2013-05-01

A new effective RF tar thermocatalytic treatment process with low energy intensive has been proposed to remove tar from biomass gasification. Toluene and naphthalene as biomass tar model compounds were removed via both thermal and catalytic treatment over a wide temperature range from 850 °C to 1200 °C and 450 °C to 900 °C, respectively at residence time of 0-0.7 s. Thermal characteristics of the new technique are also described in this paper. This study clearly clarified that toluene was much easier to be removed than naphthalene. Soot was found as the final product of thermal treatment of the tar model and completely removed during catalytic treatment. Radical reactions generated by RF non-thermal effect improve the tar removal. The study showed that Y-zeolite has better catalytic activity compared to dolomite on toluene and naphthalene removal due to its acidic nature and large surface area, even at lower reaction temperature of about 550 °C. Copyright © 2013 Elsevier Ltd. All rights reserved.

Assessment of tar pollution on the United Arab emirates beaches

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

Abu-Hilal, A.H.; Khordagui, H.K.

1993-01-01

In light of the inadequate information concerning stranded tar on the southwest beaches of the Arabian Gulf and the Gulf of Oman, particularly following the massive oil releases during the Gulf War, the present investigation was designed to provide reference-integrated information on the nature, location, and levels of stranded tar balls on the beaches of the United Arab Emirates (UAE). The recorded levels appeared to be higher than expected or previously reported. The tar distribution pattern, in addition to the degree of weathering, indicates that the massive oil release during the Gulf War did not reach the UAE shorelines. Themore » highest reported levels of stranded tar ever recorded in the Arabian Gulf at Jabal Dhannah apparently originated from oil spills and tankers' ballast water at the main oil terminal at the Al-Ruwaiss oil refinery some 10 km to the east. The surprising, relatively high levels of stranded tar on the beaches of the Gulf of Oman were solely attributed to the heavy navigation traffic close to the shorelines. 19 refs., 2 figs., 3 tabs.« less

Evidence that a sequence similar to TAR is important for induction of the JC virus late promoter by human immunodeficiency virus type 1 Tat.

PubMed Central

Chowdhury, M; Taylor, J P; Chang, C F; Rappaport, J; Khalili, K

1992-01-01

A specific RNA sequence located in the leader of all human immunodeficiency virus type 1 (HIV-1) mRNAs termed the transactivation response element, or TAR, is a primary target for induction of HIV-1 long terminal repeat activity by the HIV-1-derived trans-regulatory protein, Tat. Human neurotropic virus, JC virus (JCV), a causative agent of the degenerative demyelinating disease progressive multifocal leukoencephalopathy, contains sequences in the 5' end of the late RNA species with an extensive homology to HIV-1 TAR. In this study, we examined the possible role of the JCV-derived TAR-homologous sequence in Tat-mediated activation of the JCV late promoter (Tada et al., Proc. Natl. Acad. Sci. USA 87:3479-3483, 1990). Results from site-directed mutagenesis revealed that critical G residues required for the function of HIV-1 TAR that are conserved in the JCV TAR homolog play an important role in Tat activation of the JCV promoter. In addition, in vivo competition studies suggest that shared regulatory components mediate Tat activation of the JCV late and HIV-1 long terminal repeat promoters. Furthermore, we showed that the JCV-derived TAR sequence behaves in the same way as HIV-1 TAR in response to two distinct Tat mutants, one of which that has no ability to bind to HIV-1 TAR and another that lacks transcriptional activity on a responsive promoter. These results suggest that the TAR homolog of the JCV late promoter is responsive to HIV-1 Tat induction and thus may participate in the overall activation of the JCV late promoter mediated by this transactivation. Images PMID:1331525

Understanding the fate and transport of petroleum hydrocarbons from coal tar within gasholders.

PubMed

Coulon, Frédéric; Orsi, Roberto; Turner, Claire; Walton, Chris; Daly, Paddy; Pollard, Simon J T

2009-02-01

Coal tars have been identified as posing a threat to human health due to their toxic, mutagenic and carcinogenic characteristics. Workers involved in former gasholders decommissioning are potentially exposed to relevant concentrations of volatile and semi-volatile hydrocarbons upon opening up derelict tanks and during tar excavation/removal. While information on contaminated sites air-quality and its implications on medium-long term exposure is available, acute exposure issues associated with the execution of critical tasks are less understood. Calculations indicated that the concentration of a given contaminant in the gasholder vapour phase only depends on the coal tar composition, being only barely affected by the presence of water in the gasholder and the tar volume/void space ratio. Fugacity modelling suggested that risk-critical compounds such as benzene, naphthalene and other monocyclic and polycyclic aromatic hydrocarbons may gather in the gasholder air phase at significant concentrations. Gasholder emissions were measured on-site and compared with the workplace exposure limits (WELs) currently in use in UK. While levels for most of the toxic compounds were far lower than WELs, benzene air-concentrations where found to be above the accepted threshold. In addition due to the long exposure periods involved in gasholder decommissioning and the significant contribution given by naphthalene to the total coal tar vapour concentration, the adoption of a WEL for naphthalene may need to be considered to support operators in preventing human health risk at the workplace. The Level I fugacity approach used in this study demonstrated its suitability for applications to sealed environments such as gasholders and its further refining could provide a useful tool for land remediation risk assessors.

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

PubMed

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.

Geologic methane seeps along boundaries of Arctic permafrost thaw and melting glaciers

NASA Astrophysics Data System (ADS)

Walter Anthony, Katey M.; Anthony, Peter; Grosse, Guido; Chanton, Jeffrey

2012-06-01

Methane, a potent greenhouse gas, accumulates in subsurface hydrocarbon reservoirs, such as coal beds and natural gas deposits. In the Arctic, permafrost and glaciers form a `cryosphere cap' that traps gas leaking from these reservoirs, restricting flow to the atmosphere. With a carbon store of over 1,200Pg, the Arctic geologic methane reservoir is large when compared with the global atmospheric methane pool of around 5Pg. As such, the Earth's climate is sensitive to the escape of even a small fraction of this methane. Here, we document the release of 14C-depleted methane to the atmosphere from abundant gas seeps concentrated along boundaries of permafrost thaw and receding glaciers in Alaska and Greenland, using aerial and ground surface survey data and in situ measurements of methane isotopes and flux. We mapped over 150,000 seeps, which we identified as bubble-induced open holes in lake ice. These seeps were characterized by anomalously high methane fluxes, and in Alaska by ancient radiocarbon ages and stable isotope values that matched those of coal bed and thermogenic methane accumulations. Younger seeps in Greenland were associated with zones of ice-sheet retreat since the Little Ice Age. Our findings imply that in a warming climate, disintegration of permafrost, glaciers and parts of the polar ice sheets could facilitate the transient expulsion of 14C-depleted methane trapped by the cryosphere cap.

Associations of the Van Dyke's salamander (Plethodon vandykei) with geomorphic conditions in headwall seeps of the Cascade Range, Washington State.

Treesearch

A.P. McIntyre; R.A. Schmitz; C.M. Crisafulli

2006-01-01

We explored the association between Van Dyke's salamander (Plethodon vandykei) and hydrologic condition, geomorphology, and vegetation structure in headwall seeps in the Cascade Range of Washington State. We modeled occurrence of P. vandykei at three site scales: between seeps, within seeps, and between microhabitat sites...

Thermodynamic analysis of tar reforming through auto-thermal reforming process

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

Nurhadi, N., E-mail: nurhadi@tekmira.esdm.go.id; Diniyati, Dahlia; Efendi, M. Ade Andriansyah

2015-12-29

Fixed bed gasification is a simple and suitable technology for small scale power generation. One of the disadvantages of this technology is producing tar. So far, tar is not utilized yet and being waste that should be treated into a more useful product. This paper presents a thermodynamic analysis of tar conversion into gas producer through non-catalytic auto-thermal reforming technology. Tar was converted into components, C, H, O, N and S, and then reacted with oxidant such as mixture of air or pure oxygen. Thus, this reaction occurred auto-thermally and reached chemical equilibrium. The sensitivity analysis resulted that the mostmore » promising process performance occurred at flow rate of air was reached 43% of stoichiometry while temperature of process is 1100°C, the addition of pure oxygen is 40% and preheating of oxidant flow is 250°C. The yield of the most promising process performance between 11.15-11.17 kmol/h and cold gas efficiency was between 73.8-73.9%.The results of this study indicated that thermodynamically the conversion of tar into producer gas through non-catalytic auto-thermal reformingis more promising.« less

Groundwater contamination by organic bases derived from coal-tar wastes

USGS Publications Warehouse

Pereira, W.E.; Rostad, C.E.; Garbarino, J.R.; Hult, M.F.

1983-01-01

A fluid sample from a shallow aquifer contaminated by coal-tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily-tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily-tar phase were further purified by neutral-alumina, micro-column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography-mass spectrometry-computer (GC-MS-COM) and probe distillation-high resolution mass spectrometry (PD-HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily-tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD-HRMS. Azaarenes in the oily-tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of these compounds are discussed. ?? 1983.

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

PubMed

Hauquier, Freija; Ingels, Jeroen; Gutt, Julian; Raes, Maarten; Vanreusel, Ann

2011-01-01

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. 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 (13)C isotopic signals (ranging between -21.97±0.86‰ and -24.85±1.89‰) were indicative of a phytoplankton-derived food source. 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 for marine nematodes and may be responsible for the

Hydrocarbon geochemistry of cold seeps in the Monterey Bay National Marine Sanctuary

USGS Publications Warehouse

Lorenson, T.D.; Kvenvolden, K.A.; Hostettler, F.D.; Rosenbauer, R.J.; Orange, D.L.; Martin, J.B.

2002-01-01

Samples from four geographically and tectonically discrete cold seeps named Clam Flat, Clamfield, Horseshoe Scarp South, and Tubeworm City, within the Monterey Bay National Marine Sanctuary were analyzed for their hydrocarbon content. The sediment contains gaseous hydrocarbons and CO2, as well as high molecular weight aliphatic and aromatic hydrocarbons with various combinations of thermogenic and biogenic contributions from petroleum, marine, and terrigenous sources. Of particular interest is the cold seep site at Clamfield which is characterized by the presence of thermogenic hydrocarbons including oil that can likely be correlated with oil-saturated strata at Majors Creek near Davenport, CA, USA. At Clam Flat, the evidence for thermogenic hydrocarbons is equivocal. At Horseshoe Scarp South and Tubeworm City, hydrocarbon gases, mainly methane, are likely microbial in origin. These varied sources of hydrocarbon gases highlight the diverse chemical systems that appear at cold seep communities. ?? 2002 Elsevier Science B.V. All rights reserved.

Microbial eukaryotic distributions and diversity patterns in a deep-sea methane seep ecosystem.

PubMed

Pasulka, Alexis L; Levin, Lisa A; Steele, Josh A; Case, David H; Landry, Michael R; Orphan, Victoria J

2016-09-01

Although chemosynthetic ecosystems are known to support diverse assemblages of microorganisms, the ecological and environmental factors that structure microbial eukaryotes (heterotrophic protists and fungi) are poorly characterized. In this study, we examined the geographic, geochemical and ecological factors that influence microbial eukaryotic composition and distribution patterns within Hydrate Ridge, a methane seep ecosystem off the coast of Oregon using a combination of high-throughput 18S rRNA tag sequencing, terminal restriction fragment length polymorphism fingerprinting, and cloning and sequencing of full-length 18S rRNA genes. Microbial eukaryotic composition and diversity varied as a function of substrate (carbonate versus sediment), activity (low activity versus active seep sites), sulfide concentration, and region (North versus South Hydrate Ridge). Sulfide concentration was correlated with changes in microbial eukaryotic composition and richness. This work also revealed the influence of oxygen content in the overlying water column and water depth on microbial eukaryotic composition and diversity, and identified distinct patterns from those previously observed for bacteria, archaea and macrofauna in methane seep ecosystems. Characterizing the structure of microbial eukaryotic communities in response to environmental variability is a key step towards understanding if and how microbial eukaryotes influence seep ecosystem structure and function. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Evidence and biogeochemical implications for glacially-derived sediments in an active margin cold seep

USGS Publications Warehouse

Pohlman, John W.; Riedel, Michael; Novosel, Ivana; Bauer, James E.; Canuel, Elizabeth A.; Paull, Charles K.; Coffin, Richard B.; Grabowski, Kenneth S.; Knies, David L.; Hyndman, Roy D.; Spence, George D.

2011-01-01

Delineating sediment organic matter origins and sediment accumulation rates at gas hydratebearing and hydrocarbon seeps is complicated by the microbial transfer of 13C-depleted and 14Cdepleted methane carbon into sedimentary pools. Sediment 13C and 14C measurements from four cores recovered at Bullseye vent on the northern Cascadia margin are used to identify methane carbon assimilation into different carbon pools. While the total organic carbon (TOC) is mostly unaltered and primarily terrigenous in origin, planktonic foraminifera and the bulk carbonate display evidence of methane overprinting. Mass balance models are applied to determine the extent to which methane overprinting increased the radiocarbon ages of the biogenic foraminifera. The corrected and calibrated foraminifera ages between sediment depths of 70 and 573 cm are from 14.9 to 15.9 ka BP, which coincides with the retreat of the late Quaternary Cordilleran Ice Sheet from Vancouver Island. Uniform TOC _13C values of -24.5 ± 0.5‰ from the upper 8 meters of sediment at Bullseye vent suggest all cored material is Pleistocene-derived glacimarine material deposited as the ice edge retreated landward. Bullseye vent is located within an uplifted sediment block isolated from turbidite deposition and has been a site of non-deposition since the ice sheet retreated from the shelf. Biogeochemical implications of seep sediments being dominated by aged, organic-poor (<0.4 wt% TOC) material are that methane is the primary energy source, and microbes directly and indirectly associated with the anaerobic oxidation of methane (AOM) will dominate the seep microbial community.

Effect of water addition in a microwave assisted thermal cracking of biomass tar gasification

NASA Astrophysics Data System (ADS)

Warsita, A.; Surya, I.

2018-02-01

Producer gas from biomass gasification is plagued by the presence of tar which causes pipe blockages. Thermal and catalytic treatments in a microwave reactor have been shown to be effective methods for removing tar from producer gas. A question arises as to the possibility of enhancing the removal mechanism by adding water into the reactor. Thermal treatment with a various amount of water was added at temperatures in the range of 800-1200°C. The tar removal efficiency obtained 96.32% at the optimum temperature of 1200°C at the water to tar ratio (W/T) of 0.3. This study shows that the removal of tar by microwave irradiation with water addition is a significant and effective method in tar cracking.

Methane seep events of the southern Joetsu Knoll since middle Pleistocene based on benthic foraminifera

NASA Astrophysics Data System (ADS)

Oi, T.; Akiba, F.; Matsumoto, R.; Kakuwa, Y.

2016-12-01

Gas hydrates were collected at several sites off Joetsu which presented anomalous seismic structures. "Gas chimneys", major host structures for shallow gas hydrates, were recognized ROV off Joetsu in eastern margin of the Japan Sea, as were a number of active methane seeps. The assemblage components and carbon isotope of benthic foraminifera, which are ubiquitous in global marine settings, can indicate methane seep environments (Akimoto et al., 1994; Bhaumik and Gupta, 2007). Preliminary work by Oi et al. (2015) documented the obvious occurrences of methane related foraminifera, Rutherfordoides sp., in three core sediments recovered from Umitaka Spur, west Oki Trough and north Mogami Trough in the eastern margin of the Japan Sea, and found them to comprise the early part of the MIS 2, calculated to 28-25ka. These records suggest that active methane seep events might occur at the same time during early MIS 2, but were confined within the last 100ka. In this study, we analyzed benthic foraminiferal fossils from drilling core J04RB (core length 122 m; one of the gas hydrate bearing sites at a southern part of the Joetsu Knoll) in order to document methane seep events during the last 500ka. Firstly, we estimated sedimentation ages from diatom biostratigraphy and identification of Aso-1 tephra. Based on diatom components, we recognized a boundary between NPD (Neogene North Pacific diatom Zonations) 12 and NPD11, estimated at 300 ka (MIS8/9; Yanagisawa and Akiba, 1998). The bottom age was estimated to almost 530-560 ka (around MIS14) especially from the alternation with warm and cold diatom zones (Akiba et al., 2014). Secondary, we could suppose the paleoenvironments from benthic foraminifera as below. 1. The rare benthic foraminifera during the cold stages (MIS8, MIS10, and MIS12) indicate anoxic bottom conditions characteristic of falling sea level, just as with MIS 2. 2. We recognized the continuous distributions of tiny methane related specimens of Rutherfordoides sp

An evaluation of petrogenic hydrocarbons in northern Gulf of Alaska continental shelf sediments - The role of coastal oil seep inputs

USGS Publications Warehouse

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

2007-01-01

We compared hydrocarbons in water, suspended particulate matter (SPM), and riparian sediment collected from coastal watersheds along the Yakataga foreland with corresponding hydrocarbons in Gulf of Alaska benthic sediments. This comparison allows an evaluation of hydrocarbon contributions to marine sediments from natural oil seeps, coal and organic matter (e.g., kerogen) associated with eroding siliciclastic rocks. The samples from oil seeps show extensive loss of low-molecular weight n-alkanes (seeps. After entering the fluvial systems, hydrocarbons from seep oils are rapidly diluted, and associate with the SPM phase as oil-mineral-aggregates (OMA). Johnston Creek, the watershed containing the most prolific seep, conveys detectable seep-derived hydrocarbons to the Gulf of Alaska, but overall seep inputs are largely attenuated by the (non-seep) petrogenic hydrocarbon content of the high SPM loads. In contrast to the geochemical signature of seep oil, Gulf of Alaska benthic sediments are characterized by abundant alkylated naphthalene homologues, relatively smooth n-alkane envelopes (n-C9 through n-C34, but with elevated levels of n-C27, n-C29, and n-C31), and small UCMs. Further, hydrocarbons in benthic sediments are highly intercorrelated. Taken together, these characteristics indicate that seep oil is a negligible petrogenic hydrocarbon source to the Gulf of Alaska continental shelf. Coaly material separated from the benthic sediment samples using a dense liquid (???2.00 g cm-3) also accounted for a minor portion of the total PAH (1-6%) and total n-alkanes (0.4-2%) in the benthic samples. Most of the hydrocarbon burden in the sediments is found in the denser sediment fraction and likely derives from organic matter contributed by denudation of siliciclastic formations in

The TAR effect: when the ones who dislike become the ones who are disliked.

PubMed

Gawronski, Bertram; Walther, Eva

2008-09-01

Four studies tested whether a source's evaluations of other individuals can recursively transfer to the source, such that people who like others acquire a positive valence, whereas people who dislike others acquire a negative valence (Transfer of Attitudes Recursively; TAR). Experiment 1 provides first evidence for TAR effects, showing recursive transfers of evaluations regardless of whether participants did or did not have prior knowledge about the (dis)liking source. Experiment 2 shows that previously but not subsequently acquired knowledge about targets that were (dis)liked by a source overrode TAR effects in a manner consistent with cognitive balance. Finally, Experiments 3 and 4 demonstrate that TAR effects are mediated by higher order propositional inferences (in contrast to lower order associative processes), in that TAR effects on implicit attitude measures were fully mediated by TAR effects on explicit attitude measures. Commonalities and differences between the TAR effect and previously established phenomena are discussed.

Ground-water contamination by organic bases derived from coal-tar wastes

USGS Publications Warehouse

Pereira, Wilfred E.; Rostad, Colleen E.; Garbarino, John R.; Hult, Marc F.

1983-01-01

A fluid sample from a shallow aquifer contaminated by coal-tar wastes was analyzed for organic bases. The sample consisted of a mixture of aqueous and oily-tar phases. The phases were separated by centrifugation and filtration. Organic bases were isolated from each phase by pH adjustment and solvent extraction. Organic bases in the oily-tar phase were further purified by neutral-alumina, micro-column adsorption chromatography. Separation and identification of the organic bases in each phase were achieved by using capillary gas chromatography-mass spectrometry-computer (GC-MS-COM) and probe distillation-high resolution mass spectrometry (PD-HRMS) techniques. Organic bases present in the aqueous phase included primary aromatic amines (such as aniline, alkylated anilines, and naphthylamines) as well as azaarenes (such as alkylated pyridines, quinolines, acridine, and benzoquinolines). The oily-tar phase contained acridine, benzacridines, dibenzacridines, and numerous other azaarenes, the elemental compositions of which were determined by PD-HRMS. Azaarenes in the oily-tar phase, varying in size from 6 to 12 rings, are reported for the first time. The origin and environmental significance of these compounds are discussed.

Role of TAR RNA splicing in translational regulation of simian immunodeficiency virus from rhesus macaques.

PubMed Central

Viglianti, G A; Rubinstein, E P; Graves, K L

1992-01-01

The untranslated leader sequences of rhesus macaque simian immunodeficiency virus mRNAs form a stable secondary structure, TAR. This structure can be modified by RNA splicing. In this study, the role of TAR splicing in virus replication was investigated. The proportion of viral RNAs containing a spliced TAR structure is high early after infection and decreases at later times. Moreover, proviruses containing mutations which prevent TAR splicing are significantly delayed in replication. These mutant viruses require approximately 20 days to achieve half-maximal virus production, in contrast to wild-type viruses, which require approximately 8 days. We attribute this delay to the inefficient translation of unspliced-TAR-containing mRNAs. The molecular basis for this translational effect was examined in in vitro assays. We found that spliced-TAR-containing mRNAs were translated up to 8.5 times more efficiently than were similar mRNAs containing an unspliced TAR leader. Furthermore, these spliced-TAR-containing mRNAs were more efficiently associated with ribosomes. We postulate that the level of TAR splicing provides a balance for the optimal expression of both viral proteins and genomic RNA and therefore ultimately controls the production of infectious virions. Images PMID:1629957

Selected constituents in the smoke of domestic low tar cigarettes

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

Griest, W. H.; Quincy, R. B.; Guerin, M. R.

Thirty-two brands of domestic commercial low tar and nicotine cigarettes were analyzed for their production of tar, nicotine, nitrogen oxides (as nitric oxide), hydrogen cyanide, acrolein, carbon monoxide and carbon dioxide under standard analytical smoking conditions. Results are compared with published data for certain brands.

Social-cognitive remediation in schizophrenia: generalization of effects of the Training of Affect Recognition (TAR).

PubMed

Wölwer, Wolfgang; Frommann, Nicole

2011-09-01

In the last decade, several social cognitive remediation programs have been developed for use in schizophrenia. Though existing evidence indicates that such programs can improve social cognition, which is essential for successful social functioning, it remains unclear whether the improvements generalize to social cognitive domains not primarily addressed by the intervention and whether the improved test performance transfers into everyday social functioning. The present study investigated whether, beyond its known effects on facial affect recognition, the Training of Affect Recognition (TAR) has effects on prosodic affect recognition, theory of mind (ToM) performance, social competence in a role-play task, and more general social and occupational functioning. Thirty-eight inpatients with a diagnosis of schizophrenia or schizoaffective disorder were randomly assigned to 6 weeks of treatment with the TAR--primarily targeted at facial affect recognition-or Cognitive Remediation Training (CRT)--primarily targeted at neurocognition. Intention-to-treat analyses found significantly larger pre-post improvements with TAR than with CRT in prosodic affect recognition, ToM, and social competence and a trend effect in global social functioning. However, the effects on ToM and social competence were no longer significant in the smaller group of patients who completed treatment according to protocol. Results suggest that TAR effects generalize to other social cognitive domains not primarily addressed. TAR may also enhance social skills and social functioning, although this has to be confirmed. Results are discussed with regard to the need to improve functional outcome in schizophrenia against the background of current evidence from other social cognitive remediation approaches.

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

PubMed Central

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.

PubMed

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

The contribution of low tar cigarettes to environmental tobacco smoke

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

Chortyk, O.T.; Schlotzhauer, W.S.

A series of low tar cigarettes (LTC) were smoked and the quantities of condensable mainstream (inhaled) and sidestream (between puffs) smoke compounds were determined and compared to those produced by a high tar, nonfilter cigarette. It was found that the LTC produced large quantities of sidestream smoke condensates, about equal to the high tar cigarette, and contained very high levels of toxic or cocarcinogenic phenols. On an equal weight basis, the LTC emitted more of these hazardous compounds into sidestream and environmental tobacco smoke. Higher smoke yields of a flavor additive and a sugar degradation product indicated addition of suchmore » compounds during the manufacture of LTC. It was concluded that, compared to a high tar cigarette, smoking LTC may be better for the smoker, but not for the nearby nonsmoker. Information should be developed to allow smokers to choose LTC that produce lower levels of hazardous compounds in their environmentally emitted sidestream smoke.« less

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

NASA Astrophysics Data System (ADS)

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

the northern South China Sea. Several sediment pore water profiles nearly at the cold seep vent showed the characteristic loss of SO42-, and the increase of CH4, H2S and HS- peaks. Dissolved S8 and CH4had been first found at the fluids under the lush biological communities of the cold seep. This may indicate some bacteria mats at the lush biological communities oxidize hydrogen sulfide and produce elemental sulfur as a byproduct. Our research suggests that the in situ observed H2S:HS-, and HSO4-:SO42- ratios provide elegant pH sensitive "dyes" with which to diagnose the geochemical reactions occurring.

Creating fluid injectivity in tar sands formations

DOEpatents

Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan

2012-06-05

Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons including mobilized hydrocarbons are produced from the portion.

Creating fluid injectivity in tar sands formations

DOEpatents

Stegemeier, George Leo; Beer, Gary Lee; Zhang, Etuan

2010-06-08

Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons are produced from the portion.

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

NASA Astrophysics Data System (ADS)

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.

investigating the use of geophysical techniques to detect hydrocarbon seeps

NASA Astrophysics Data System (ADS)

Somwe, Vincent Tambwe

In the Cement oil field, seeps occur in the Hydrocarbon Induced Diagenetic Aureole (HIDA).This 14 square km diagenetic alteration region is mainly characterized by the: (1) secondary carbonate minerals deposition that tends to form ridges throughout the oil field; (2) disseminated pyrite in the vicinity of the fault zones; (3) uranium occurrence and the change in color pattern from red to bleached red sandstone. Generally the HIDA of the Cement oil field is subdivided into four zones: (1) carbonate cemented sandstone zone (zone 1), (2) altered sandstone zone (zone 2), (3) sulfide zone (zone 3) and (4) unaltered sandstone zone (zone 4). This study investigated the use of geophysical techniques to detect alteration zones over the Cement oil field. Magnetic and electromagnetic data were acquired at 5 m interval using the geometric G858 magnetometer and the Geonics EM-31 respectively. Both total magnetic intensity and bulk conductivity were found to decrease across boundaries between unaltered and altered sandstones. Boundaries between sulfide and carbonate zones, which in most cases were located in fault zones, were found to be characterized by higher magnetic and bulk conductivity readings. The contrast between the background and the highest positive peak was found to be in the range of 0.5-10% for total magnetic intensity and 258-450% for bulk conductivity respectively; suggesting that the detection of hydrocarbon seeps would be more effective with EM techniques. The study suggests that geophysical techniques can be used to delineate contact between the different alteration zones especially where metallic minerals such as pyrite are precipitated. The occurrence of carbonate cemented sandstone in the Cement oil field can be used as a pathfinder for hydrocarbon reservoir. The change in color in the altered sandstone zone can still be useful in the hydrocarbon exploration.

PAH volatilization following application of coal-tar-based pavement sealant

USGS Publications Warehouse

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (ΣPAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 μg m-2 h-1 and decreased rapidly during the 45 days after application to 160 μg m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ΣPAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ΣPAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ΣPAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

Landsat detection of oil from natural seeps

USGS Publications Warehouse

Deutsch, M.; Estes, J.E.

1980-01-01

Oil on the ocean surface from the natural seeps in the Santa Barbara Channel, California, could not be detected on frames of any of the four bands of standard Landsat positive or negative film transparencies, nor could the slicks be detected using digital scaling, density slicing, or ratioing techniques. Digital contrast-stretch enhancement, however, showed the distribution of oil on the surface. - from Authors

Did shifting seawater sulfate concentrations drive the evolution of deep-sea methane-seep ecosystems?

PubMed

Kiel, Steffen

2015-04-07

The origin and evolution of the faunas inhabiting deep-sea hydrothermal vents and methane seeps have been debated for decades. These faunas rely on a local source of sulfide and other reduced chemicals for nutrition, which spawned the hypothesis that their evolutionary history is independent from that of photosynthesis-based food chains and instead driven by extinction events caused by deep-sea anoxia. Here I use the fossil record of seep molluscs to show that trends in body size, relative abundance and epifaunal/infaunal ratios track current estimates of seawater sulfate concentrations through the last 150 Myr. Furthermore, the two main faunal turnovers during this time interval coincide with major changes in seawater sulfate concentrations. Because sulfide at seeps originates mostly from seawater sulfate, variations in sulfate concentrations should directly affect the base of the food chain of this ecosystem and are thus the likely driver of the observed macroecologic and evolutionary patterns. The results imply that the methane-seep fauna evolved largely independently from developments and mass extinctions affecting the photosynthesis-based biosphere and add to the growing body of evidence that the chemical evolution of the oceans had a major impact on the evolution of marine life. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

21 CFR 740.18 - Coal tar hair dyes posing a risk of cancer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Coal tar hair dyes posing a risk of cancer. 740.18... (CONTINUED) COSMETICS COSMETIC PRODUCT WARNING STATEMENTS Warning Statements § 740.18 Coal tar hair dyes... coal tar hair dye containing any ingredient listed in paragraph (b) of this section shall bear, in...

Metal concentrations in the mussel Bathymodiolus platifrons from a cold seep in the South China Sea

NASA Astrophysics Data System (ADS)

Wang, Xiaocheng; Li, Chaolun; Zhou, Li

2017-11-01

Data regarding the concentration and distribution of various metals in different tissues of mussels from the cold seep is scant. We aimed to quantify the presence of twenty elements (Ca, K, Mg, Sr, Ag, Al, As, Ba, Cd, Co, Cr, Cu, Li, Fe, Mn, Mo, Ni, Pb, V, and Zn) in gills, mantles and shells of Bathymodiolus platifrons, a common mussel species in deep-sea cold seep and hydrothermal vent communities. Specimens of B. platifrons were sampled from a cold seep at the northern continental slope of the South China Sea and the elemental contents in its tissues were quantified. Our findings were compared to data from taxonomically similar species at hydrothermal vents and coastal waters. We found that most elements were significantly enriched in the gills, which could be related to food uptake and the existence of endosymbionts. In shells and mantles, Mn was particularly rich, possibly due to its replacement of Ca in the carbonate structure. A significant positive correlation among Ca, Sr, and Mg was found in both gills and mantles, consistent with relationships observed in vent and littoral mussel species. Concentrations of metals were highest in the new-growth outer edges of shells in comparison to older shell material, which suggests that trace metals have become more abundant in the ambient seawater in recent years. Compared with other deep-sea environments and coastal areas, metal accumulation showed local variability but similar overall patterns of uptake and accumulation, indicating that essential elemental requirements in different mussel species may be similar across taxa. The high bioconcentration factor (BCF) values of Mn and Ag suggest that their particular functions and regulation mechanisms are related to specific adaptations and life cycle processes.

Impact of anaerobic oxidation of methane on the geochemical cycle of redox-sensitive elements at cold-seep sites of the northern South China Sea

NASA Astrophysics Data System (ADS)

Hu, Yu; Feng, Dong; Liang, Qianyong; Xia, Zhen; Chen, Linying; Chen, Duofu

2015-12-01

Cold hydrocarbon seepage is a frequently observed phenomenon along continental margins worldwide. However, little is known about the impact of seeping fluids on the geochemical cycle of redox-sensitive elements. Pore waters from four gravity cores (D-8, D-5, D-7, and D-F) collected from cold-seep sites of the northern South China Sea were analyzed for SO42-, Mg2+, Ca2+, Sr2+, dissolved inorganic carbon (DIC), δ13CDIC, dissolved Fe, Mn, and trace elements (e.g. Mo, U). The sulfate concentration-depth profiles, δ13CDIC values and (ΔDIC+ΔCa2++ΔMg2+)/ΔSO42- ratios suggest that organoclastic sulfate reduction (OSR) is the dominant process in D-8 core. Besides OSR, anaerobic oxidation of methane (AOM) is partially responsible for depletion of sulfate at D-5 and D-7 cores. The sulfate consumption at D-F core is predominantly caused by AOM. The depth of sulfate-methane interface (SMI) and methane diffusive flux of D-F core are calculated to be ~7 m and 0.035 mol m-2 yr-1, respectively. The relatively shallow SMI and high methane flux at D-F core suggest the activity of gas seepage in this region. The concentrations of dissolved uranium (U) were inferred to decrease significantly within the iron reduction zone. It seems that AOM has limited influence on the U geochemical cycling. In contrast, a good correlation between the consumption of sulfate and the removal of molybdenum (Mo) suggests that AOM has a significantly influence on the geochemical cycle of Mo at cold seeps. Accordingly, cold seep environments may serve as an important potential sink in the marine geochemical cycle of Mo.

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

USGS Publications Warehouse

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.

Microsporidia-nematode associations in methane seeps reveal basal fungal parasitism in the deep sea

PubMed Central

Sapir, Amir; Dillman, Adler R.; Connon, Stephanie A.; Grupe, Benjamin M.; Ingels, Jeroen; Mundo-Ocampo, Manuel; Levin, Lisa A.; Baldwin, James G.; Orphan, Victoria J.; Sternberg, Paul W.

2013-01-01

The deep sea is Earth's largest habitat but little is known about the nature of deep-sea parasitism. In contrast to a few characterized cases of bacterial and protistan parasites, the existence and biological significance of deep-sea parasitic fungi is yet to be understood. Here we report the discovery of a fungus-related parasitic microsporidium, Nematocenator marisprofundi n. gen. n. sp. that infects benthic nematodes at methane seeps on the Pacific Ocean floor. This infection is species-specific and has been temporally and spatially stable over 2 years of sampling, indicating an ecologically consistent host-parasite interaction. A high distribution of spores in the reproductive tracts of infected males and females and their absence from host nematodes' intestines suggests a sexual transmission strategy in contrast to the fecal-oral transmission of most microsporidia. N. marisprofundi targets the host's body wall muscles causing cell lysis, and in severe infection even muscle filament degradation. Phylogenetic analyses placed N. marisprofundi in a novel and basal clade not closely related to any described microsporidia clade, suggesting either that microsporidia-nematode parasitism occurred early in microsporidia evolution or that host specialization occurred late in an ancient deep-sea microsporidian lineage. Our findings reveal that methane seeps support complex ecosystems involving interkingdom interactions between bacteria, nematodes, and parasitic fungi and that microsporidia parasitism exists also in the deep-sea biosphere. PMID:24575084

Understanding the stability of pyrolysis tars from biomass in a view point of free radicals.

PubMed

He, Wenjing; Liu, Qingya; Shi, Lei; Liu, Zhenyu; Ci, Donghui; Lievens, Caroline; Guo, Xiaofen; Liu, Muxin

2014-03-01

Fast pyrolysis of biomass has attracted increasing attention worldwide to produce bio-tars that can be upgraded into liquid fuels and chemicals. However, the bio-tars are usually poor in quality and stability and are difficult to be upgraded. To better understand the nature of the bio-tars, this work reveals radical concentration of tars derived from pyrolysis of two kinds of biomass. The tars were obtained by condensing the pyrolysis volatiles in 3s. It shows that the tars contain large amounts of radicals, at a level of 10(16)spins/g, and are able to generate more radicals at temperatures of 573K or higher, reaching a level of 10(19)spins/g at 673K in less than 30min. The radical generation in the tar samples is attributed to the formation of THF insoluble matters (coke), which also contain radicals. The radical concentrations of the aqueous liquids obtained in pyrolysis are also studied. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

Catalytic Tar Reduction for Assistance in Thermal Conversion of Space Waste for Energy Production

NASA Technical Reports Server (NTRS)

Caraccio, Anne Joan; Devor, Robert William; Hintze, Paul E.; Muscatello, Anthony C.; Nur, Mononita

2014-01-01

The Trash to Gas (TtG) project investigates technologies for converting waste generated during spaceflight into various resources. One of these technologies was gasification, which employed a downdraft reactor designed and manufactured at NASA's Kennedy Space Center (KSC) for the conversion of simulated space trash to carbon dioxide. The carbon dioxide would then be converted to methane for propulsion and water for life support systems. A minor byproduct of gasification includes large hydrocarbons, also known as tars. Tars are unwanted byproducts that add contamination to the product stream, clog the reactor and cause complications in analysis instrumentation. The objective of this research was to perform reduction studies of a mock tar using select catalysts and choose the most effective for primary treatment within the KSC downdraft gasification reactor. Because the KSC reactor is operated at temperatures below typical gasification reactors, this study evaluates catalyst performance below recommended catalytic operating temperatures. The tar reduction experimentation was observed by passing a model tar vapor stream over the catalysts at similar conditions to that of the KSC reactor. Reduction in tar was determined using gas chromatography. Tar reduction efficiency and catalyst performances were evaluated at different temperatures.

Coal-tar-based pavement sealants—a potent source of PAHs

USGS Publications Warehouse

Mahler, Barbara J.; Van Metre, Peter C.

2017-01-01

P avement sealants are applied to the asphalt pavement of many parking lots, driveways, and even playgrounds in North America (Figure 1), where, when first applied, they render the pavement glossy black and looking like new. Sealant products used commercially in the central, eastern, and northern United States typically are coal-tarbased, whereas those used in the western United States typically are asphalt-based. Although the products look similar, they are chemically different. Coal-tarbased pavement sealants typically are 25-35 percent (by weight) coal tar or coal-tar pitch, materials that are known human carcinogens and that contain high concentrations of polycyclic aromatic hydrocarbons (PAHs) and related chemicals (unless otherwise noted, all Figure 1. Pavement sealant is commonly used to seal parking lots, playgrounds, and driveways throughout the United States. Sealants used in the central, northern, eastern, and southern United States typically contain coal tar or coal-tar pitch, both of which are known human carcinogens. Photos by the U.S. Geological Survey. data in this article are from Mahler et al. 2012 and references therein).

PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States

USGS Publications Warehouse

Van Metre, P.C.; Mahler, B.J.; Wilson, J.T.

2009-01-01

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-tar-based sealcoat dominates use, and three cities in the western U. S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2. 1 and 0. 8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

Methane-Oxidizing Bacteria Shunt Carbon to Microbial Mats at a Marine Hydrocarbon Seep

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

Paul, Blair G.; Ding, Haibing; Bagby, Sarah C.

The marine subsurface is a reservoir of the greenhouse gas methane. While microorganisms living in water column and seafloor ecosystems are known to be a major sink limiting net methane transport from the marine subsurface to the atmosphere, few studies have assessed the flow of methane-derived carbon through the benthic mat communities that line the seafloor on the continental shelf where methane is emitted. We analyzed the abundance and isotope composition of fatty acids in microbial mats grown in the shallow Coal Oil Point seep field off Santa Barbara, CA, USA, where seep gas is a mixture of methane andmore » CO 2. We further used stable isotope probing (SIP) to track methane incorporation into mat biomass. We found evidence that multiple allochthonous substrates supported the rich growth of these mats, with notable contributions from bacterial methanotrophs and sulfur-oxidizers as well as eukaryotic phototrophs. Fatty acids characteristic of methanotrophs were shown to be abundant and 13C-enriched in SIP samples, and DNA-SIP identified members of the methanotrophic family Methylococcaceae as major 13CH 4 consumers. Members of Sulfuricurvaceae, Sulfurospirillaceae, and Sulfurovumaceae are implicated in fixation of seep CO 2. The mats’ autotrophs support a diverse assemblage of co-occurring bacteria and protozoa, with Methylophaga as key consumers of methane-derived organic matter. This study identifies the taxa contributing to the flow of seep-derived carbon through microbial mat biomass, revealing the bacterial and eukaryotic diversity of these remarkable ecosystems.« less

Methane-Oxidizing Bacteria Shunt Carbon to Microbial Mats at a Marine Hydrocarbon Seep

DOE PAGES

Paul, Blair G.; Ding, Haibing; Bagby, Sarah C.; ...

2017-02-27

The marine subsurface is a reservoir of the greenhouse gas methane. While microorganisms living in water column and seafloor ecosystems are known to be a major sink limiting net methane transport from the marine subsurface to the atmosphere, few studies have assessed the flow of methane-derived carbon through the benthic mat communities that line the seafloor on the continental shelf where methane is emitted. We analyzed the abundance and isotope composition of fatty acids in microbial mats grown in the shallow Coal Oil Point seep field off Santa Barbara, CA, USA, where seep gas is a mixture of methane andmore » CO 2. We further used stable isotope probing (SIP) to track methane incorporation into mat biomass. We found evidence that multiple allochthonous substrates supported the rich growth of these mats, with notable contributions from bacterial methanotrophs and sulfur-oxidizers as well as eukaryotic phototrophs. Fatty acids characteristic of methanotrophs were shown to be abundant and 13C-enriched in SIP samples, and DNA-SIP identified members of the methanotrophic family Methylococcaceae as major 13CH 4 consumers. Members of Sulfuricurvaceae, Sulfurospirillaceae, and Sulfurovumaceae are implicated in fixation of seep CO 2. The mats’ autotrophs support a diverse assemblage of co-occurring bacteria and protozoa, with Methylophaga as key consumers of methane-derived organic matter. This study identifies the taxa contributing to the flow of seep-derived carbon through microbial mat biomass, revealing the bacterial and eukaryotic diversity of these remarkable ecosystems.« less

Methane-Oxidizing Bacteria Shunt Carbon to Microbial Mats at a Marine Hydrocarbon Seep

PubMed Central

Paul, Blair G.; Ding, Haibing; Bagby, Sarah C.; Kellermann, Matthias Y.; Redmond, Molly C.; Andersen, Gary L.; Valentine, David L.

2017-01-01

The marine subsurface is a reservoir of the greenhouse gas methane. While microorganisms living in water column and seafloor ecosystems are known to be a major sink limiting net methane transport from the marine subsurface to the atmosphere, few studies have assessed the flow of methane-derived carbon through the benthic mat communities that line the seafloor on the continental shelf where methane is emitted. We analyzed the abundance and isotope composition of fatty acids in microbial mats grown in the shallow Coal Oil Point seep field off Santa Barbara, CA, USA, where seep gas is a mixture of methane and CO2. We further used stable isotope probing (SIP) to track methane incorporation into mat biomass. We found evidence that multiple allochthonous substrates supported the rich growth of these mats, with notable contributions from bacterial methanotrophs and sulfur-oxidizers as well as eukaryotic phototrophs. Fatty acids characteristic of methanotrophs were shown to be abundant and 13C-enriched in SIP samples, and DNA-SIP identified members of the methanotrophic family Methylococcaceae as major 13CH4 consumers. Members of Sulfuricurvaceae, Sulfurospirillaceae, and Sulfurovumaceae are implicated in fixation of seep CO2. The mats’ autotrophs support a diverse assemblage of co-occurring bacteria and protozoa, with Methylophaga as key consumers of methane-derived organic matter. This study identifies the taxa contributing to the flow of seep-derived carbon through microbial mat biomass, revealing the bacterial and eukaryotic diversity of these remarkable ecosystems. PMID:28289403

Metal catalysts for steam reforming of tar derived from the gasification of lignocellulosic biomass.

PubMed

Li, Dalin; Tamura, Masazumi; Nakagawa, Yoshinao; Tomishige, Keiichi

2015-02-01

Biomass gasification is one of the most important technologies for the conversion of biomass to electricity, fuels, and chemicals. The main obstacle preventing the commercial application of this technology is the presence of tar in the product gas. Catalytic reforming of tar appears a promising approach to remove tar and supported metal catalysts are among the most effective catalysts. Nevertheless, improvement of catalytic performances including activity, stability, resistance to coke deposition and aggregation of metal particles, as well as catalyst regenerability is greatly needed. This review focuses on the design and catalysis of supported metal catalysts for the removal of tar in the gasification of biomass. The recent development of metal catalysts including Rh, Ni, Co, and their alloys for steam reforming of biomass tar and tar model compounds is introduced. The role of metal species, support materials, promoters, and their interfaces is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sulfur biogeochemistry of cold seeps in the Green Canyon region of the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Formolo, Michael J.; Lyons, Timothy W.

2013-10-01

Cold seeps in the Gulf of Mexico provide a natural laboratory to study biogeochemical cycling of sulfur, carbon, and oxygen at hydrate- and hydrocarbon-rich deep marine settings with obvious additional relevance to studies of diverse modern and ancient seeps. Of particular interest are the sulfur isotope signatures of microbial sulfate reduction coupled to anaerobic oxidation of methane and other non-methane liquid and gaseous hydrocarbons. Whereas most of the published sulfur isotope data from cold seep systems pertain to pore-water species, our study integrates both solid and dissolved sulfur: acid-volatile sulfides (SAVS), pyrite (Spy), elemental sulfur (S°), dissolved sulfate and ΣH2S. Modeled and 35SO42- reduction rates and δ13C and δ18O data for authigenic carbonates are integrated within this sulfur framework. Our results indicate extreme variability over narrow spatial and temporal scales within short distances (meters) from active seeps. High rates of microbial sulfate reduction can lead to complete consumption of the sulfate within the upper few centimeters of burial, while meters away the sulfate profile shows little depletion. Such small-scale variability must reflect the structure and temporal dynamics of hydrocarbon migration in the presence of low amounts of background organic matter. Our past work demonstrated that electron donors other than methane drive significant levels of microbial activity at these seeps, and very recent work has demonstrated that oxidation of higher chain volatile hydrocarbons can contribute to the high levels of microbial activity. These findings are consistent with our new results. Elevated concentrations of pyrite and diagenetic carbonate relative to background sediments are diagnostic of active seepage, yet the S isotopes tell more complex stories. Low levels of the transient, 'instantaneous' products of S cycling-AVS and S°-show high δ34S values that increase with depth. Most of the pyrite formation, however, seems

Wet scrubbing of biomass producer gas tars using vegetable oil

NASA Astrophysics Data System (ADS)

Bhoi, Prakashbhai Ramabhai

The overall aims of this research study were to generate novel design data and to develop an equilibrium stage-based thermodynamic model of a vegetable oil based wet scrubbing system for the removal of model tar compounds (benzene, toluene and ethylbenzene) found in biomass producer gas. The specific objectives were to design, fabricate and evaluate a vegetable oil based wet scrubbing system and to optimize the design and operating variables; i.e., packed bed height, vegetable oil type, solvent temperature, and solvent flow rate. The experimental wet packed bed scrubbing system includes a liquid distributor specifically designed to distribute a high viscous vegetable oil uniformly and a mixing section, which was designed to generate a desired concentration of tar compounds in a simulated air stream. A method and calibration protocol of gas chromatography/mass spectroscopy was developed to quantify tar compounds. Experimental data were analyzed statistically using analysis of variance (ANOVA) procedure. Statistical analysis showed that both soybean and canola oils are potential solvents, providing comparable removal efficiency of tar compounds. The experimental height equivalent to a theoretical plate (HETP) was determined as 0.11 m for vegetable oil based scrubbing system. Packed bed height and solvent temperature had highly significant effect (p0.05) effect on the removal of model tar compounds. The packing specific constants, Ch and CP,0, for the Billet and Schultes pressure drop correlation were determined as 2.52 and 2.93, respectively. The equilibrium stage based thermodynamic model predicted the removal efficiency of model tar compounds in the range of 1-6%, 1-4% and 1-2% of experimental data for benzene, toluene and ethylbenzene, respectively, for the solvent temperature of 30° C. The NRTL-PR property model and UNIFAC for estimating binary interaction parameters are recommended for modeling absorption of tar compounds in vegetable oils. Bench scale

Acid Tar Lagoons: Management and Recovery

NASA Astrophysics Data System (ADS)

Bohers, Anna; Hroncová, Emília; Ladomerský, Juraj

2017-04-01

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

Porous Carbon Nanofibers from Electrospun Biomass Tar/Polyacrylonitrile/Silver Hybrids as Antimicrobial Materials.

PubMed

Song, Kunlin; Wu, Qinglin; Zhang, Zhen; Ren, Suxia; Lei, Tingzhou; Negulescu, Ioan I; Zhang, Quanguo

2015-07-15

A novel route to fabricate low-cost porous carbon nanofibers (CNFs) using biomass tar, polyacrylonitrile (PAN), and silver nanoparticles has been demonstrated through electrospinning and subsequent stabilization and carbonization processes. The continuous electrospun nanofibers had average diameters ranging from 392 to 903 nm. The addition of biomass tar resulted in increased fiber diameters, reduced thermal stabilities, and slowed cyclization reactions of PAN in the as-spun nanofibers. After stabilization and carbonization, the resultant CNFs showed more uniformly sized and reduced average diameters (226-507 nm) compared to as-spun nanofibers. The CNFs exhibited high specific surface area (>400 m(2)/g) and microporosity, attributed to the combined effects of phase separations of the tar and PAN and thermal decompositions of tar components. These pore characteristics increased the exposures and contacts of silver nanoparticles to the bacteria including Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, leading to excellent antimicrobial performances of as-spun nanofibers and CNFs. A new strategy is thus provided for utilizing biomass tar as a low-cost precursor to prepare functional CNFs and reduce environmental pollutions associated with direct disposal of tar as an industrial waste.

Estimating tar and nicotine exposure: human smoking versus machine generated smoke yields.

PubMed

St Charles, F K; Kabbani, A A; Borgerding, M F

2010-02-01

Determine human smoked (HS) cigarette yields of tar and nicotine for smokers using their own brand in their everyday environment. A robust, filter analysis method was used to estimate the tar and nicotine yields for 784 subjects. Seventeen brands were chosen to represent a wide range of styles: 85 and 100 mm lengths; menthol and non-menthol; 17, 23, and 25 mm circumference; with tar yields [Federal Trade Commission (FTC) method] ranging from 1 to 18 mg. Tar bands chosen corresponded to yields of 1-3 mg, 4-6 mg, 7-12 mg, and 13+ mg. A significant difference (p<0.0001) in HS yields of tar and nicotine between tar bands was found. Machine-smoked yields were reasonable predictors of the HS yields for groups of subjects, but the relationship was neither exact nor linear. Neither the FTC, the Massachusetts (MA) nor the Canadian Intensive (CI) machine-smoking methods accurately reflect the HS yields across all brands. The FTC method was closest for the 7-12 mg and 13+ mg products and the MA method was closest for the 1-3mg products. The HS yields for the 4-6 mg products were approximately midway between the FTC and the MA yields. HS nicotine yields corresponded well with published urinary and plasma nicotine biomarker studies. 2009 Elsevier Inc. All rights reserved.

Using Multi-Disciplinary Data to Compile a Hydrocarbon Budget for GC600, a Natural Seep in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

MacDonald, I. R.; Johansen, C.; Marty, E.; Natter, M.; Silva, M.; Hill, J. C.; Viso, R. F.; Lobodin, V.; Diercks, A. R.; Woolsey, M.; Macelloni, L.; Shedd, W. W.; Joye, S. B.; Abrams, M.

2016-12-01

Fluid exchange between the deep subsurface and the overlying ocean and atmosphere occurs at hydrocarbon seeps along continental margins. Seeps are key features that alter the seafloor morphology and geochemically affect the sediments that support chemosynthetic communities. However, the dynamics and discharge rates of hydrocarbons at cold seeps remain largely unconstrained. Here we merge complementary geochemical (oil fingerprinting), geophysical (seismic, subbottom, backscatter, multibeam) and video/imaging (Video Time Lapse Camera, DSV ALVIN video) data sets to constrain pathways and magnitudes of hydrocarbon fluxes from the source rock to the seafloor at a well-studied, prolific seep site in the Northern Gulf of Mexico (GC600). Oil fingerprinting showed compositional similarities for samples from the following collections: the reservoir, an active vent, and the sea-surface. This was consistent with reservoir structures and pathways identified in seismic data. Video data, which showed the spatial distribution of seep indicators such as bacteria mats, or hydrate outcrops at the sediment interface, were combined with known hydrocarbon fluxes from the literature and used to quantify the total hydrocarbon fluxes in the seep domain. Using a systems approach, we combined data sets and published values at various scales and resolutions to compile a preliminary hydrocarbon budget for the GC600 seep site. Total estimated in-flow of hydrocarbons was 2.07 x 109 mol/yr. The combined total of out-flow and sequestration amounted to 7.56 x 106 mol/yr leaving a potential excess (in-flow - out-flow) of 2.06 x 109 mol/yr. Thus quantification of the potential out-flow from the seep domains based on observable processes does not equilibrate with the theoretical inputs from the reservoir. Processes that might balance this budget include accumulation of gas hydrate and sediment free-gas, as well as greater efficiency of biological sinks.

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 8 2014-07-01 2014-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 8 2011-07-01 2011-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 8 2012-07-01 2012-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

29 CFR 1926.1102 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1926.1102 Section 1926.1102 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Hazardous Substances § 1926.1102 Coal tar pitch volatiles; interpretation of term. Note: The requirements...

Geochemical characteristics of the barite deposits at cold seeps from the northern Gulf of Mexico continental slope

NASA Astrophysics Data System (ADS)

Feng, Dong; Roberts, Harry H.

2011-09-01

Although less common than the occurrence of authigenic carbonate, barite has been observed frequently at cold seeps on continental margins worldwide. It is understood that barite forms by the interaction of barium-rich and sulfate-free seeping fluids with dissolved sulfate of pore water near the seafloor, but questions remain about the geochemical processes and mode(s) of the barite formation. Here, we report geochemical characteristics of barite deposits at 11 cold seep locations from the northern Gulf of Mexico continental slope. Samples from these sites of fluid and gas expulsion provide environmental information on barite formation. Seafloor observations and samples acquired indicate that barites occur as chimneys, cones, crusts, irregular mound-like buildups up to 2-meters high, and as a material disseminated in host sediment. Most barite samples are white-to-gray and usually have a porous fabric and layered internal structure. Mineralogically, samples of barite may contain a significant amounts of carbonate minerals, such as calcite and dolomite, but aragonite is absent in all samples analyzed in this study. Negative δ 13C values (as low as - 46.4‰ V-PDB) of the associated carbonates strongly suggests that methane is the primary carbon source. The δ 34S and δ 18O values of the barites have large variations, ranging from 18‰ to 80.4‰ V-CDT, and 7.5‰ to 26.7‰ V-SMOW, respectively. On δ 34S versus δ 18O plots, many barite deposits show a linear trend that projects down toward the isotopic composition of seawater sulfate. The trend suggests that barite formed from seawater sulfate that has been isotopically modified to varying degrees by biological sulfate reduction. The δ 34S/δ 18O ratios vary between 2.4 and 4.1. The variations are interpreted to reflect local controls on the flux of barium-rich seep fluids, changes in the rate of bacterial sulfate reduction, and/or the openness of pore fluid system. The 87Sr/ 86Sr values of the barites

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

NASA Astrophysics Data System (ADS)

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.

Task 3.9 -- Catalytic tar cracking. Semi-annual report, January 1--June 30, 1995

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

Young, B.C.; Timpe, R.C.

1995-12-31

Tar produced in the gasification of coal is deleterious to the operation of downstream equipment including fuel cells, gas turbines, hot-gas stream cleanup filters, and pressure swing adsorption systems. Catalytic cracking of tars to smaller hydrocarbons can be an effective means to remove these tars from gas streams and, in the process, generate useful products, e.g., methane gas, which is crucial to the operation of molten carbonate fuel cells. The objectives of this project are to investigate whether gasification tars can be cracked by synthetic nickel-substituted micamontmorillonite, zeolite, or dolomite material; and whether the tars can be cracked selectively bymore » these catalysts to produce a desired liquid and/or gas stream. Results to date are presented in the cited papers.« less

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

PubMed Central

Levin, Lisa A.; Mendoza, Guillermo F.; Grupe, Benjamin M.; Gonzalez, Jennifer P.; Jellison, Brittany; Rouse, Greg; Thurber, Andrew R.; Waren, Anders

2015-01-01

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 carbonate δ13

Microwave-induced cracking of pyrolytic tars coupled to microwave pyrolysis for syngas production.

PubMed

Beneroso, D; Bermúdez, J M; Montes-Morán, M A; Arenillas, A; Menéndez, J A

2016-10-01

Herein a new process is proposed to produce a syngas-rich gas fraction (>80vol% H2+CO) from biowaste based on microwave heating within two differentiated steps in order to avoid tars production. The first step consists of the microwave pyrolysis of biowaste induced by a char-based susceptor at 400-800°C; tars, char and syngas-rich gas fractions being produced. The tars are then fed into the second step where a portion of the char from the first step is used as a bed material in a 0.3:1wt% ratio. This bed is heated up by microwaves up to 800°C, allowing thermal cracking of tars and additional syngas (>90vol% H2+CO) being then produced. This new concept arises as an alternative technology to the gasification of biowastes for producing syngas with no need for catalysts or gasifying reagents to minimise tars production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Relation Between PAHs and Coal-Tar-Based Pavement Sealant in Urban Environments (Invited)

NASA Astrophysics Data System (ADS)

Mahler, B. J.; van Metre, P. C.

2010-12-01

Since 2003, coal-tar-based sealant products have come under increased scrutiny as a source of PAHs in urban environments. Sealant (or sealcoat) is the black, shiny substance often applied to asphalt pavement, in particular parking lots and driveways, for esthetic and maintenance purposes. Coal-tar-based sealant, one of the two primary pavement sealant types on the market, typically is 20-35 percent coal-tar pitch, a known carcinogen that is more than 50 percent polycyclic aromatic hydrocarbons (PAHs). The PAH content of the coal-tar-based sealant product is about 1,000 times that of a similar, asphalt-based product, on average. This difference is reflected in regional differences in sealant use and PAH concentrations in pavement dust. In the central and eastern U.S., where the coal-tar-based formulation is prevalent, ΣPAH in mobile particles from sealed pavement have been shown to be about 1,000 times higher than in the western U.S., where the asphalt-based formulation is prevalent (the median ΣPAH concentrations are 2,200 mg/kg in the central and eastern U.S. and 2.1 mg/kg in the western U.S.). Source apportionment modeling indicates that, in the central and eastern U.S., particles from sealed pavement are contributing the majority of the PAHs in recently deposited (post-1990) lake sediment, with implications for ecological health, and that coal-tar-based sealant is the primary cause of upward trends in PAHs in U.S. urban lakes. From the standpoint of human health, research indicates that mobile particles from parking lots with coal-tar-based sealant are tracked indoors, resulting in elevated PAH concentrations in house dust. Coal-tar-based sealcoat being applied to an asphalt parking lot at the University of Texas Pickle Research Center.

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

29 CFR 1915.1002 - Coal tar pitch volatiles; interpretation of term.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Coal tar pitch volatiles; interpretation of term. 1915.1002 Section 1915.1002 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH... Toxic and Hazardous Substances § 1915.1002 Coal tar pitch volatiles; interpretation of term. Note: The...

Methane-derived carbonates form at the sediment-bedrock interface in a shallow marine gas seep.

NASA Astrophysics Data System (ADS)

Kimball, J.; Ding, H.; Valentine, D. L.

2006-12-01

Hydrocarbon seeps occur world-wide, and release large quantities of oil and natural gas to the ocean and atmosphere. One of the world's most prolific hydrocarbon seep fields is located just offshore from Goleta, CA, and serves as the study site for this investigation. In the course of investigating gas fluxes from a 10 m deep coastal seep, samples of seafloor bedrock were collected by scuba diving during a time of low sediment burden. These samples were found to be concretions composed primarily of carbonate-cemented sand. The delta13C values of the carbonate range from -25 to -32 per mille, and indicate a role for methane oxidation in the formation of the carbonates. Long chain fatty acids were extracted from the concretions and were quantified, identified, and analyzed for their 13C composition. Fatty acids typical of sulfate reducing bacteria were observed, and interpreted as a signature of anoxia. Further mineralogical and isotopic studies are planned. From these observations we interpret a shallow water origin for these concretions, whereby the seasonal migration of sand to the seep environment drives anoxia and anaerobic methane oxidation at the sediment-bedrock interface. The alkalinity generated from sulfate reduction causes the precipitation of methane-derived carbonate- which forms a concretion with sand.

Aviation Turbine Fuels from Tar Sands Bitumen and Heavy Oils. Part 1. Process Analysis.

DTIC Science & Technology

1984-09-01

Uinta Basin .......................too.... 11 b . Asphalt Ridge ........................ 13 c.* Tar Sand Triangle ..... to .. .. . .. .. . 15 e...Estimated ............**..* 7 3 CHARACTERISTICS OF UTAH’S MAJOR TAR SANDS ....... 12 4 UINTA BASIN DEPOSITS ................... *........ 13 *.5 UINTA ...7 UINTA BASIN , UTAH PROPERTIES -SUNNYSIDE ........ 20 8 UINTA BASIN , UTAH PROPERTIES -P. R. SPRINGS . 22 r9 ESTIMATED CALIFORNIA TAR SAND DISTRIBUTION

High density of structurally controlled, shallow to deep water fluid seep indicators imaged offshore Costa Rica

NASA Astrophysics Data System (ADS)

Kluesner, Jared W.; Silver, Eli A.; Bangs, Nathan L.; McIntosh, Kirk D.; Gibson, James; Orange, Daniel; Ranero, Cesar R.; von Huene, Roland

2013-03-01

We used high-resolution mapping to document 161 sites of potential fluid seepage on the shelf and slope regions where no geophysical seep indicators had been reported. Identified potential seabed seepage sites show both high-backscatter anomalies and bathymetric expressions, such as pockmarks, mounds, and ridges. Almost all identified seabed features are associated with bright spots and flat spots beneath, as mapped within the 3-D seismic grid. We obtained EM122 multi-beam data using closely spaced receiver beams and 4-5 times overlapping multi-beam swaths, which greatly improved the sounding density and geologic resolvability of the data. At least one location shows an acoustic plume in the water column on a 3.5 kHz profile, and this plume is located along a fault trace and above surface and subsurface seepage indicators. Fluid indicators are largely associated with folds and faults within the sediment section, and many of the faults continue into and offset the reflective basement. A dense pattern of normal faults is seen on the outer shelf in the multi-beam bathymetry, backscatter, and 3-D seismic data, and the majority of fluid seepage indicators lie along mapped fault traces. Furthermore, linear mounds, ridges, and pockmark chains are found on the upper, middle, and lower slope regions. The arcuate shape of the shelf edge, projection of the Quepos Ridge, and high density of potential seep sites suggest that this area may be a zone of former seamount/ridge subduction. These results demonstrate a much greater potential seep density and distribution than previously reported across the Costa Rican margin.

Influence of the presence of PAHs and coal tar on naphthalene sorption in soils

NASA Astrophysics Data System (ADS)

Bayard, Rémy; Barna, Ligia; Mahjoub, Borhane; Gourdon, Rémy

2000-11-01

concentrations (about 120 mg/kg) in the soil. In contrast, experiments carried out with coal tar particles revealed a significant effect. Naphthalene sorption appeared to be proportional to the amount of coal tar added to the sand or soil, and a much higher affinity of naphthalene for XOM ( Koc above 2000 cm 3/g) than SOM ( Koc around 300 cm 3/g) was observed. Naphthalene transport in the columns of sand or soil spiked with coal tar particles was simulated very satisfactorily with a dual double-domain model. Around 90% of naphthalene retention by coal tar was found to occur within the organic phase, suggesting a phase partition process which may be explained by the amorphous nature of the XOM and its extreme affinity for naphthalene. For SOM, however, which is present as porous microaggregates of clay and humic substances, with less affinity for naphthalene, only 1/3 of naphthalene retention was found to occur within the organic phase, underlining the significant role of surface adsorption in the short term behavior of naphthalene in soil. For longer contact times, the model simulations proposed in the present study should be coupled to slow sorption, aging and biodegradation models to describe long-term behavior of naphthalene in soil-tar-water systems.

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

NASA Astrophysics Data System (ADS)

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

Metagenomics in methane seep detection and studies of the microbial methane sediment filter

NASA Astrophysics Data System (ADS)

Gunn Rike, Anne; Håvelsrud, Othilde Elise; Haverkamp, Thomas; Kristensen, Tom; Jakobsen, Kjetill

2013-04-01

Metanotrophic prokaryotes with their capacity to oxidize methane to biomass and CO2 contribute considerably in reduction of the global methane emission from oceans. Metagenomic studies of seabed sediments represent a new approach to detect marine methane seeps and to study whether the inhabiting microbial consortium represent a microbial methane filter. We have used next generation high throughput DNA sequencing technology to study microbial consortia and their potential metabolic processes in marine sediment samples from the Håkon Mosby mud volcano (HMMV) in the Barents Sea, the Tonya Seep in the Coal Oil Point area in California and from the pockmarked area at the Troll oil and gas field in the North Sea. Annotation of archaeal reads from the HMMV metagenome resulted in hits to all enzymes supposed to be involved in the anaerobic oxidation of methane (AOM) carried out by anaerobic methanotrophic archaea (ANME). The presence of several ANME taxa at HMMV has previously been well described (1). The stratification analysis of the Tonya seep sediment showed that both aerobic and anaerobic methanotrophs were present at both layers investigated, although total archaea, ANME-1, ANME-2 and ANME-3 were overabundant in the deepest layer. Several sulphate reducing taxa (possibly syntrophic ANME partners) were detected. The Tonya Seep sediment represent a robust methane filter where presently dominating methanotrophic taxa could be replaced by less abundant methanotrophs should the environmental conditions change (2). In the Troll pockmarked sediments several methanotrophic taxa including ANME-1, ANME-2 and candidate division NC10 were detected although there was an overabundance of autotrophic nitrifiers (e.g. Nitrosopumilis, Nitrococcus, Nitrospira) using CO2 as the carbon source. Methane migrating upwards through the sediments is probably oxidized to CO2 in AOM resulting in an upward CO2 flux. The CO2 entering the seafloor may contribute to maintain the pockmark structure

PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States

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

Peter C. Van Metre; Barbara J. Mahler; Jennifer T. Wilson

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U.S. cities that show nationwide patterns in concentrations of {Sigma}PAHs associated with sealcoat. Dust was swept from parking lots in six cities in the central and eastern U.S., where coal-tar-based sealcoat dominates use, and three cities in the western U.S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg,more » respectively. For three western cities, median SPAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2.1 and 0.8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo(a)pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted. 30 refs., 4 figs., 2 tabs.« less

Identification of sources of tar balls deposited along the Southwest Caspian Coast, Iran using fingerprinting techniques.

PubMed

Shirneshan, Golshan; Bakhtiari, Alireza Riyahi; Memariani, Mahmoud

2016-10-15

In 2012, a significant number of tar balls occurred along the Southwest coasts of the Caspian Sea (Iran). Several oil fields of Turkmenistan, Azerbaijan and Iran might be sources of oil spills and lead to the formation of these tar balls. For source identification, 6 tar ball samples were collected from the Southwest beaches of the Caspian Sea and subjected to fingerprint analysis based on the distribution of the source-specific biomarkers of pentacyclic tri-terpanes and steranes. Comparing the diagenic ratios revealed that the tar balls were chemically similar and originated from the same source. Results of double ratio plots (e.g., C29/C30 versus ∑C31-C35/C30 and C28 αββ/(C27 αββ+C29 αββ) versus C29 αββ/(C27 αββ+C28 αββ)) in the tar balls and oils from Iran, Turkmenistan and Azerbaijan indicated that the tar balls might be the result of spills from Turkmenistan oil. Moreover, principle component analysis (PCA) using biomarker ratios on the tar balls and 20 crude oil samples from different wells of Azerbaijan, Iran and Turkmenistan oils showed that the tar balls collected at the Southwest beaches are highly similar to the Turkmenistan oil but one of the Azerbaijan oils (from Bahar field oils) was found to be also slightly close to the tar balls. The weathering characterizations based on the presence of UCM (unresolved complex mixture) and low/high molecular weight ratios (L/H) of alkanes and PAHs indicated the tar ball samples have been significantly influenced by natural weathering processes such as evaporation, photo-degradation and biodegradation. This is the first study of its kind in Iran to use fingerprinting for source identification of tar balls. Copyright © 2016 Elsevier B.V. All rights reserved.

The diversity and biogeography of late Pleistocene birds from the lowland Neotropics

NASA Astrophysics Data System (ADS)

Steadman, David W.; Oswald, Jessica A.; Rincón, Ascanio D.

2015-05-01

The Neotropical lowlands sustain the world's richest bird communities, yet little that we know about their history is based on paleontology. Fossils afford a way to investigate distributional shifts in individual species, and thus improve our understanding of long-term change in Neotropical bird communities. We report a species-rich avian fossil sample from a late Pleistocene tar seep (Mene de Inciarte) in northwestern Venezuela. A mere 175 identified fossils from Mene de Inciarte represent 73 species of birds, among which six are extinct, and eight others no longer occur within 100 km. These 14 species consist mainly of ducks (Anatidae), snipe (Scolopacidae), vultures/condors (Vulturidae), hawks/eagles (Accipitridae), and blackbirds (Icteridae). Neotropical bird communities were richer in the late Pleistocene than today; their considerable extinction may be related to collapse of the large mammal fauna at that time. The species assemblage at Mene de Inciarte suggests that biogeographic patterns, even at continental scales, have been remarkably labile over short geological time frames. Mene de Inciarte is but one of 300 + tar seeps in Venezuela, only two of which have been explored for fossils. We may be on the cusp of an exciting new era of avian paleontology in the Neotropics.

Coal-tar-based pavement sealcoat—Potential concerns for human health and aquatic life

USGS Publications Warehouse

Mahler, Barbara J.; Woodside, Michael D.; Van Metre, Peter C.

2016-04-20

Aquatic Life Concerns—Runoff from coal-tar-sealcoated pavement, even runoff collected more than 3 months after sealcoat application, is acutely toxic to fathead minnows and water fleas, two species commonly used to assess toxicity to aquatic life. Exposure to even highly diluted runoff from coal-tar-sealcoated pavement can cause DNA damage and impair DNA repair. These findings demonstrate that coal-tar-sealcoat runoff can remain a risk to aquatic life for months after application.

Catalytic decomposition of tar derived from wood waste pyrolysis using Indonesian low grade iron ore as catalyst

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

Wicakso, Doni Rahmat; Chemical Engineering Department, Faculty of Engineering, Gadjah Mada University, Jalan Grafika No. 2 Bulaksumur, Yogyakarta, 55281; Sutijan

Low grade iron ore can be used as an alternative catalyst for bio-tar decomposition. Compared to other catalysts, such as Ni, Rd, Ru, Pd and Pt, iron ore is cheaper. The objective of this research was to investigate the effect of using low grade iron ore as catalyst for tar catalytic decomposition in fixed bed reactor. Tar used in this experiment was pyrolysis product of wood waste while the catalyst was Indonesian low grade iron ore. The variables studied were temperatures between 500 – 600 °C and catalyst weight between 0 – 40 gram. The first step, tar was evaporatedmore » at 450 °C to produce tar vapor. Then, tar vapor was flowed to fixed bed reactor filled low grade iron ore. Gas and tar vapor from reactor was cooled, then the liquid and uncondensable gas were analyzed by GC/MS. The catalyst, after experiment, was weighed to calculate total carbon deposited into catalyst pores. The results showed that the tar components that were heavy and light hydrocarbon were decomposed and cracked within the iron ore pores to from gases, light hydrocarbon (bio-oil) and carbon, thus decreasing content tar in bio-oil and increasing the total gas product. In conclusion, the more low grade iron ore used as catalyst, the tar content in the liquid decrease, the H{sup 2} productivity increased and calorimetric value of bio-oil increased.« less

The search for a source rock for the giant Tar Sand triangle accumulation, southeastern Utah

USGS Publications Warehouse

Huntoon, J.E.; Hansley, P.L.; Naeser, N.D.

1999-01-01

A large proportion (about 36%) of the world's oil resource is contained in accumulations of heavy oil or tar. In these large deposits of degraded oil, the oil in place represents only a fraction of what was present at the time of accumulation. In many of these deposits, the source of the oil is unknown, and the oil is thought to have migrated over long distances to the reservoirs. The Tar Sand triangle in southeastern Utah contains the largest tar sand accumulation in the United States, with 6.3 billion bbl of heavy oil estimated to be in place. The deposit is thought to have originally contained 13-16 billion bbl prior to the biodegradation, water washing, and erosion that have taken place since the middle - late Tertiary. The source of the oil is unknown. The tar is primarily contained within the Lower Permian White Rim Sandstone, but extends into permeable parts of overlying and underlying beds. Oil is interpreted to have migrated into the White Rim sometime during the Tertiary when the formation was at a depth of approximately 3500 m. This conclusion is based on integration of fluid inclusion analysis, time-temperature reconstruction, and apatite fission-track modeling for the White Rim Sandstone. Homogenization temperatures cluster around 85-90??C for primary fluid inclusions in authigenic, nonferroan dolomite in the White Rim. The fluid inclusions are associated with fluorescent oil-bearing inclusions, indicating that dolomite precipitation was coeval with oil migration. Burial reconstruction suggests that the White Rim Sandstone reached its maximum burial depth from 60 to 24 Ma, and that maximum burial was followed by unroofing from 24 to 0 Ma. Time-temperature modeling indicates that the formation experienced temperatures of 85-90??C from about 35 to 40 Ma during maximum burial. Maximum formation temperatures of about 105-110??C were reached at about 24 Ma, just prior to unroofing. Thermal modeling is used to examine the history of potential source rocks

Phytotoxicity and Plant Productivity Analysis of Tar-Enriched Biochars

NASA Astrophysics Data System (ADS)

Keller, M. L.; Masiello, C. A.; Dugan, B.; Rudgers, J. A.; Capareda, S. C.

2008-12-01

Biochar is one of the three by-products obtained by the pyrolysis of organic material, the other two being syngas and bio-oil. The pyrolysis of biomass has generated a great amount of interest in recent years as all three by-products can be put toward beneficial uses. As part of a larger project designed to evaluate the hydrologic impact of biochar soil amendment, we generated a biochar through fast pyrolysis (less than 2 minutes) of sorghum stock at 600°C. In the initial biochar production run, the char bin was not purged with nitrogen. This inadvertent change in pyrolysis conditions produced a fast-pyrolysis biochar enriched with tars. We chose not to discard this batch, however, and instead used it to test the impact of tar-enriched biochars on plants. A suite of phytotoxicity tests were run to assess the effects of tar-rich biochar on plant germination and plant productivity. We designed the experiment to test for negative effects, using an organic carbon and nutrient-rich, greenhouse- optimized potting medium instead of soil. We used Black Seeded Simpson lettuce (Lactuca sativa) as the test organism. We found that even when tars are present within biochar, biochar amendment up to 10% by weight caused increased lettuce germination rates and increased biomass productivity. In this presentation, we will report the statistical significance of our germination and biomass data, as well as present preliminary data on how biochar amendment affects soil hydrologic properties.

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

PubMed

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

NASA Astrophysics Data System (ADS)

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

Carbazole is a naturally occurring inhibitor of angiogenesis and inflammation isolated from antipsoriatic coal tar

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

Jack L. Arbiser; Baskaran Govindarajan; Traci E. Battle

2006-06-15

Coal tar is one of the oldest and an effective treatment for psoriasis. Coal tar has been directly applied to the skin, or used in combination with UV light as part of the Goeckerman treatment. The use of coal tar has caused long-term remissions in psoriasis, but has fallen out of favor because the treatment requires hospitalization and coal tar is poorly acceptable aesthetically to patients. Thus, determining the active antipsoriatic component of coal tar is of considerable therapeutic interest. We fractionated coal tar into its components, and tested them using the SVR angiogenesis inhibitor assay. Treatment of SVR endothelialmore » cells with coal tar fractions resulted in the isolation of a single fraction with antiangiogenic activity. The active antiangiogenic compound in coal tar is carbazole. In addition to antiangiogenic activity, carbazole inhibited the production of inflammatory IL-15 by human mononuclear cells. IL-15 is elevated in psoriasis and is thought to contribute to psoriatic inflammation. Carbazole treatment also reduced activity of inducible nitric oxide synthase (iNOS), which is proinflammatory and elevated in psoriasis. The effect of carbazole on upstream pathways in human psoriasis was determined, and carbazole was shown to inhibit signal transducer and activator of transcription (stat)3-mediated transcription, which has been shown to be relevant in human psoriasis. IL-15, iNOS, and stat3 activation require the activation of the small GTPase rac for optimal activity. Carbazole was found to inhibit rac activation as a mechanism for its inhibition of downstream inflammatory and angiogenic pathways. Given its antiangiogenic and anti-inflammatory activities, carbazole is likely a major component of the antipsoriatic activity of coal tar. Carbazole and derivatives may be useful in the therapy of human psoriasis.« less

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

PubMed

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.

Bilaterally cleft lip, limb defects, and haematological manifestations: Roberts syndrome versus TAR syndrome.

PubMed

Urban, M; Opitz, C; Bommer, C; Enders, H; Tinschert, S; Witkowski, R

1998-09-23

We report on a 13-year-old patient followed since birth. He is the only offspring of young, non-consanguineous German parents. His mother has an isolated left cleft of lip and a cleft palate. At birth, our patient presented with bilaterally cleft lip/cleft palate, phocomelia of upper limbs with normal hands, and mild symmetrical deficiencies of the long bones of the lower limbs. Haematological evaluation demonstrated a leukaemoid reaction during a urinary tract infection as well as intermittent thrombocytopenia and episodes of marked eosinophilia during the first two years of life. Intellectual development has been normal. Comparison with two similar cases from the literature suggests a non-random phenotypic overlap of Roberts syndrome (MIM 268300) and TAR syndrome (MIM 274000). Such clinical constellations may be key observations to understand the genetic relationship of Roberts syndrome and TAR syndrome in future phenotype-genotype correlations.

Reduced tar, nicotine, and carbon monoxide exposure while smoking ultralow- but not low-yield cigarettes

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

Benowitz, N.L.; Jacob, P. III; Yu, L.

An unresolved public health issue is whether some modern cigarettes are less hazardous than other and whether patients who cannot stop smoking should be advised to switch to lower-yield cigarettes. The authors studied tar (estimated by urine mutagenicity), nicotine, and carbon monoxide exposure in habitual smokers switched from their usual brand to high- (15 mg of tar), low- (5 mg of tar), or ultralow-yield (1 mg of tar) cigarettes. There were no differences in exposure comparing high- or low-yield cigarettes, but tar and nicotine exposures were reduced by 49% and 56%, respectively, and carbon monoxide exposure by 36% while smokingmore » ultralow-yield cigarettes. Similarly, in 248 subjects smoking their self-selected brand, nicotine intake, estimated by blood concentrations of its metabolite continine, was 40% lower in those who smoked ultralow but no different in those smoking higher yields of cigarettes. The data indicate that ultralow-yield cigarettes do deliver substantial doses of tar, nicotine, and carbon monoxide, but that exposure are considerably less than for other cigarettes.« less

Formation of modern and Paleozoic stratiform barite at cold methane seeps on continental margins

USGS Publications Warehouse

Torres, M.E.; Bohrmann, G.; Dube, T.E.; Poole, F.G.

2003-01-01

Stratiform (bedded) Paleozoic barite occurs as large conformable beds within organic- and chert-rich sediments; the beds lack major sulfide minerals and are the largest and most economically significant barite deposits in the geologic record. Existing models for the origin of bedded barite fail to explain all their characteristics: the deposits display properties consistent with an exhalative origin involving fluid ascent to the seafloor, but they lack appreciable polymetallic sulfide minerals and the corresponding strontium isotopic composition to support a hydrothermal vent source. A new mechanism of barite formation, along structurally controlled sites of cold fluid seepage in continental margins, involves barite remobilization in organic-rich, highly reducing sediments, transport of barium-rich fluids, and barite precipitation at cold methane seeps. The lithologic and depositional framework of Paleozoic and cold seep barite, as well as morphological, textural, and chemical characteristics of the deposits, and associations with chemosymbiotic fauna, all support a cold seep origin for stratiform Paleozoic barite. This understanding is highly relevant to paleoceanographic and paleotectonic studies, as well as to economic geology.

Geology and structure of the Pine River, Florida River, Carbon Junction, and Basin Creek gas seeps, La Plata County, Colorado

USGS Publications Warehouse

Fassett, James E.; Condon, Steven M.; Huffman, A. Curtis; Taylor, David J.

1997-01-01

Introduction: This study was commissioned by a consortium consisting of the Bureau of Land Management, Durango Office; the Colorado Oil and Gas Conservation Commission; La Plata County; and all of the major gas-producing companies operating in La Plata County, Colorado. The gas-seep study project consisted of four parts; 1) detailed surface mapping of Fruitland Formation coal outcrops in the above listed seep areas, 2) detailed measurement of joint and fracture patterns in the seep areas, 3) detailed coal-bed correlation of Fruitland coals in the subsurface adjacent to the seep areas, and 4) studies of deep-seated seismic patterns in those seep areas where seismic data was available. This report is divided into three chapters labeled 1, 2, and 3. Chapter 1 contains the results of the subsurface coal-bed correla-tion study, chapter 2 contains the results of the surface geologic mapping and joint measurement study, and chapter 3, contains the results of the deep-seismic study. A preliminary draft of this report was submitted to the La Plata County Group in September 1996. All of the members of the La Plata Group were given an opportunity to critically review the draft report and their comments were the basis for revising the first draft to create this final version of a geologic report on the major La Plata County gas seeps located north of the Southern Ute Indian Reservation.

Pollutant sensitivity of the endangered Tar River Spinymussel as assessed by single chemical and effluent toxicity tests

USGS Publications Warehouse

Augspurger, Thomas P.; Wang, Ning; Kunz, James L.; Ingersoll, Christopher G.

2014-01-01

The federally endangered Tar River spinymussel (Elliptio steinstansana) is endemic to the Tar River and Neuse River systems in North Carolina. The extent to which water quality limits Tar River spinymussels’ recovery is important to establish, and one aspect of that is understanding the species’ pollutant sensitivity. The primary objectives of this study were to 1) develop captive propagation and culture methods for Tar River spinymussels; 2) determine the pollutant sensitivity of captively propagated Tar River spinymussels; 3) examine the utility of the non-endangered yellow lance (Elliptio lanceolata), yellow lampmussel (Lampsilis cariosa) and notched rainbow (Villosa constricta) as surrogates for the Tar River spinymussels’ chemical sensitivity; 4) develop a 7-d method for conducting effluent toxicity tests starting with newly transformed mussels; 5) assess the toxicity of municipal wastewater effluents discharged into the Tar River spinymussels’ current and historic habitat; and, 6) evaluate the protection afforded by existing effluent toxicity test requirements.

Effects of human chromosome 12 on interactions between Tat and TAR of human immunodeficiency virus type 1.

PubMed Central

Alonso, A; Cujec, T P; Peterlin, B M

1994-01-01

Rates of transcriptions of the human immunodeficiency virus are greatly increased by the viral trans activator Tat. In vitro, Tat binds to the 5' bulge of the trans-activation response (TAR) RNA stem-loop, which is present in all viral transcripts. In human cells, the central loop in TAR and its cellular RNA-binding proteins are also critical for the function of Tat. Previously, we demonstrated that in rodent cells (CHO cells), but not in those which contain the human chromosome 12 (CHO12 cells), Tat-TAR interactions are compromised. In this study, we examined the roles of the bulge and loop in TAR in Tat trans activation in these cells. Whereas low levels of trans activation depended solely on interactions between Tat and the bulge in CHO cells, high levels of trans activation depended also on interactions between Tat and the loop in CHO12 cells. Since the TAR loop binding proteins in these two cell lines were identical and different from their human counterpart, the human chromosome 12 does not encode TAR loop binding proteins. In vivo binding competition studies with TAR decoys confirmed that the binding of Tat to TAR is more efficient in CHO12 cells. Thus, the protein(s) encoded on human chromosome 12 helps to tether Tat to TAR via its loop, which results in high levels of trans activation. Images PMID:8083988

Impact of genetic variants on haematopoiesis in patients with thrombocytopenia absent radii (TAR) syndrome.

PubMed

Manukjan, Georgi; Bösing, Hendrik; Schmugge, Markus; Strauß, Gabriele; Schulze, Harald

2017-11-01

Thrombocytopenia absent radii (TAR) syndrome is clearly defined by the combination of radial aplasia and reduced platelet counts. The genetics of TAR syndrome has recently been resolved and comprises a microdeletion on Chromosome 1 including the RBM8A gene and a single nucleotide polymorphism (SNP) either at the 5' untranslated region (5'UTR) or within the first intron of RBM8A. Although phenotypically readily diagnosed after birth, the genetic determination of particular SNPs in TAR syndrome harbours valuable information to evaluate disease severity and treatment decisions. Here, we present clinical data in a cohort of 38 patients and observed that platelet counts in individuals with 5'UTR SNP are significantly lower compared to patients bearing the SNP in intron 1. Moreover, elevated haemoglobin values could only be assessed in patients with 5'UTR SNP whereas white blood cell count is unaffected, indicating that frequently observed anaemia in TAR patients could also be SNP-dependent whereas leucocytosis does not correlate with genetic background. However, this report on a large cohort provides an overview of important haematological characteristics in TAR patients, facilitating evaluation of the various traits in this disease and indicating the importance of genetic validation for TAR syndrome. © 2017 John Wiley & Sons Ltd.

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

NASA Astrophysics Data System (ADS)

Li, M.; Jin, X.

2003-04-01

The northern part of South China Sea is of passive continental margin, which geologic units include shelf, slope and deep sea basin. There are rifting basins forming during Paleogene (or Cretaceous ?) to Quaternary developed on shelf and slope, which sediments are dominated by fluvial and lake clastic rock of Paleogene, and marine clastic rock and carbonate of Neogene - Quaternary. The main basins include the Pearl River Mouth Basin, Beibu Gulf basin, Qiongdongnan Basin and Yinggehai basin. They contain rich oil and gas resources, and have become important industrial oil and gas producing region in South China Sea. With the increasing of petroleum exploration actives and marine petroleum engineering, it has been paid more attention to the investigation and research of gas seeps and shallow gas, for they become a potential threaten to the marine engineering while they are regarded as the indicators of industrial oil and gas. By study the distribution and geochemical characteristics of gas seeps in northeast part of Yinggehai basin and shallow gas in sediments on slope, combined with their regional geologic background, this paper deals with the origin, migration pathway and emission mechanism of gas seeps and shallow gas in northern part of South China Sea, for providing a base knowledge for the evaluation of marine engineering geology. In northeast part of Yinggehai basin gas seeps have been found and recorded for near 100 years. During 1990s, as a part of petroleum exploration, the gas seeps in the basin have been investigated and research by oil companies (Baojia Huang et al., 1992; Jiaqiong He et al., 2000). Gas seeps were found in shallow water area along southwest coast of Hainan Island, water depth usually less than 50 m. The occurrence of gas seeps can be divided into two types: (1) gas continuously emission, continuous gas bubbles groups can be detected by sonar underwater and observed on water surface. (2) gas intermittently emission, the time intervals

Technology for the production of Zero Q.I pitch from coal tar

NASA Astrophysics Data System (ADS)

Karthik, K.; Kumar, K. Rajesh; Rao, C. V. Nageswara; Kumar, B. Vinod; Murty, J. V. S.

2013-06-01

Zero Quinoline Insolubles (Q.I) pitch is a special type of pitch obtained from pre-treatment of coal tar, which is converted into pitch. This is used for impregnation of electrodes for improving the strength, electrical properties and also used as a pre-cursor for Mesophase pitch for producing Mesophase pitch based carbon fibers, carbon foam, and Meso carbon micro beads. This paper discusses the technology of Q.I separation from Coal Tar by using decantation of Coal Tar mixed with Heavy Creosote Oil (HC Oil) at different temperatures. By this method we were able to produce the Zero Q.I pitch with a Q.I value of 0.1%.

Creating and maintaining a gas cap in tar sands formations

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael; Dinkoruk, Deniz Sumnu; Wellington, Scott Lee

2010-03-16

Methods for treating a tar sands formation are disclosed herein. Methods for treating a tar sands formation may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. Pressure may be allowed to increase in an upper portion of the formation to provide a gas cap in the upper portion. At least some hydrocarbons are produced from a lower portion of the formation.

HYFLUX: Satellite Exploration of Natural Hydrocarbon Seeps and Discovery of a Methane Hydrate Mound at GC600

NASA Astrophysics Data System (ADS)

Garcia-Pineda, O. G.; MacDonald, I. R.; Shedd, W.; Zimmer, B.

2009-12-01

Analysis of natural hydrocarbon seeps is important to improve our understanding of methane flux from deeper sediments to the water column. In order to quantify natural hydrocarbon seep formations in the Northern Gulf of Mexico, a set of 686 Synthetic Aperture Radar (SAR) images was analyzed using the Texture Classifying Neural Network Algorithm (TCNNA), which processes SAR data to delineate oil slicks. This analysis resulted in a characterization of 396 natural seep sites distributed in the northern GOM. Within these sites, a maximum of 1248 individual vents where identified. Oil reaching the sea-surface is deflected from its source during transit through the water column. This presentation describes a method for estimating locations of active oil vents based on repeated slick detection in SAR. One of the most active seep formations was detected in MMS lease block GC600. A total of 82 SAR scenes (collected by RADARSAT-1 from 1995 to 2007) was processed covering this region. Using TCNNA the area covered by each slick was computed and Oil Slicks Origins (OSO) were selected as single points within detected oil slicks. At this site, oil slick signatures had lengths up to 74 km and up to 27 km^2 of area. Using SAR and TCNNA, four active vents were identified in this seep formation. The geostatistical mean centroid among all detections indicated a location along a ridge-line at ~1200m. Sea truth observations with an ROV, confirmed that the estimated location of vents had a maximum offset of ~30 m from their actual locations on the seafloor. At the largest vent, a 3-m high, 12-m long mound of oil-saturated gas hydrate was observed. The outcrop contained thousands of ice worms and numerous semi-rigid chimneys from where oily bubbles were escaping in a continuous stream. Three additional vents were found along the ridge; these had lower apparent flow, but were also plugged with gas hydrate mounds. These results support use of SAR data for precise delineation of active seep

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

PubMed

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.

Spatial Structure and Activity of Sedimentary Microbial Communities Underlying a Beggiatoa spp. Mat in a Gulf of Mexico Hydrocarbon Seep

PubMed Central

Lloyd, Karen G.; Albert, Daniel B.; Biddle, Jennifer F.; Chanton, Jeffrey P.; Pizarro, Oscar; Teske, Andreas

2010-01-01

Background Subsurface fluids from deep-sea hydrocarbon seeps undergo methane- and sulfur-cycling microbial transformations near the sediment surface. Hydrocarbon seep habitats are naturally patchy, with a mosaic of active seep sediments and non-seep sediments. Microbial community shifts and changing activity patterns on small spatial scales from seep to non-seep sediment remain to be examined in a comprehensive habitat study. Methodology/Principal Findings We conducted a transect of biogeochemical measurements and gene expression related to methane- and sulfur-cycling at different sediment depths across a broad Beggiatoa spp. mat at Mississippi Canyon 118 (MC118) in the Gulf of Mexico. High process rates within the mat (∼400 cm and ∼10 cm from the mat's edge) contrasted with sharply diminished activity at ∼50 cm outside the mat, as shown by sulfate and methane concentration profiles, radiotracer rates of sulfate reduction and methane oxidation, and stable carbon isotopes. Likewise, 16S ribosomal rRNA, dsrAB (dissimilatory sulfite reductase) and mcrA (methyl coenzyme M reductase) mRNA transcripts of sulfate-reducing bacteria (Desulfobacteraceae and Desulfobulbaceae) and methane-cycling archaea (ANME-1 and ANME-2) were prevalent at the sediment surface under the mat and at its edge. Outside the mat at the surface, 16S rRNA sequences indicated mostly aerobes commonly found in seawater. The seep-related communities persisted at 12–20 cm depth inside and outside the mat. 16S rRNA transcripts and V6-tags reveal that bacterial and archaeal diversity underneath the mat are similar to each other, in contrast to oxic or microoxic habitats that have higher bacterial diversity. Conclusions/Significance The visual patchiness of microbial mats reflects sharp discontinuities in microbial community structure and activity over sub-meter spatial scales; these discontinuities have to be taken into account in geochemical and microbiological inventories of seep environments. In

Physicochemical Approaches for the Remediation of Former Manufactured Gas Plant Tars

NASA Astrophysics Data System (ADS)

Hauswirth, S.; Miller, C. T.

2014-12-01

Former manufactured gas plant (FMGP) tars are one of the most challenging non-aqueous phase liquid (NAPL) contaminants to remediate due to their complex chemical composition, high viscosities, and ability to alter wettability. In this work, we investigate several in situ remediation techniques for the removal of tar from porous media. Batch and column experiments were conducted to test the effectiveness of mobilization, solubilization, and chemical oxidation remediation approaches. Alkaline (NaOH), surfactant (Triton X-100), and polymer (xanthan gum) agents were used in various combinations to reduce tar-water interfacial tension, increase flushing solution viscosity, and increase the solubilities of tar components. Base-activated sodium persulfate was used alone and in combination with surfactant to chemically oxidized tar components. The effectiveness of each method was assessed in terms of both removal of PAHs from the system and reduction of dissolved-phase effluent polycyclic aromatic hydrocarbon (PAH) concentrations. In column studies, alkaline-polymer (AP) and alkaline-surfactant-polymer (ASP) solutions efficiently mobilized 81-93% and 95-96% of residual PAHs, respectively, within two pore volumes. The impact of AP flushing on dissolved-phase PAH concentrations was relatively low; however, the concentrations of several low molar mass PAHs were significantly reduced after ASP flushing. Surfactant-polymer (SP) solutions removed over 99% of residual PAHs through a combination of mobilization and solubilization, and reduced the post-remediation, dissolved-phase total PAH concentration by 98.4-99.1%. Degradation of residual PAHs by base-activated sodium persulfate was relatively low (30-50%), and had little impact on dissolved-phase PAH concentrations.

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

NASA Astrophysics Data System (ADS)

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

Thermal Cracking of Tars in a Continuously Fed Reactor with Steam

DTIC Science & Technology

2011-05-01

Fluidized Bed using biomass 8 Tars  Mixture of organic components present in gasification product gas with high molecular weight hydrocarbons [MW...Disable sulfur removal systems FoulingPlugging [Ref. 3: Biomass Gasification – Tar and Particles in Product Gases Sampling and Analysis”, European...P., and Nussbaumer T., “Gas Cleaning Requirements for Internal Combustion Engine Applications of Fixed Bed Biomass Gasification ”, Biomass and

Cold Preparation of Heroin in a Black Tar Market.

PubMed

Roth, Alexis M; Armenta, Richard F; Wagner, Karla D; Strathdee, Steffanie A; Goldshear, Jesse L; Cuevas-Mota, Jazmine; Garfein, Richard S

2017-07-29

Black tar heroin is typically prepared for injection with heat which decreases the risk of HIV transmission by inactivating the virus. We received reports that persons who inject drugs (PWID) in Tijuana, Baja California, Mexico, a black tar heroin market, were using only water to dissolve heroin. Because Tijuana abuts San Diego County, CA, United States, we undertook the present analyses to determine the prevalence of this practice among PWID in San Diego, California. PWID completed quarterly behavioral assessments and serological testing for blood-borne viruses. Bivariate and multivariable logistic regression models were constructed to assess for individual, social, and structural correlates of preparing heroin without heat within the preceding 6 months. Nearly half of black tar heroin users (149/305) reported they had prepared heroin without heat within 6 months. In multivariable analysis, cold preparation was independently associated with younger age (10 year decrease; AOR = 1.25; 95% CI 1.03, 1.53), more drug injecting acquaintances (per 5 acquaintance increase; AOR = 1.05; 95% CI 1.01, 1.09) and prefilled syringe use (injecting drugs from syringes that are already filled with drugs before purchase; AOR = 1.86; 95% CI 1.14, 3.02). Conclusions/Importance: To our knowledge, this is the first paper to report that PWID living in a black tar heroin market are preparing heroin without heat. Additional research is needed to determine whether this is an endemic practice or PWID are engaging in new forms of drug preparation in response to changes in the environment.

The Auxin Biosynthetic TRYPTOPHAN AMINOTRANSFERASE RELATED TaTAR2.1-3A Increases Grain Yield of Wheat.

PubMed

Shao, An; Ma, Wenying; Zhao, Xueqiang; Hu, Mengyun; He, Xue; Teng, Wan; Li, Hui; Tong, Yiping

2017-08-01

Controlling the major auxin biosynthetic pathway to manipulate auxin content could be a target for genetic engineering of crops with desired traits, but little progress had been made because low or high auxin contents often cause developmental inhibition. Here, we performed a genome-wide analysis of bread wheat ( Triticum aestivum ) to identify the Tryptophan Aminotransferase of Arabidopsis1/Tryptophan Aminotransferase-Related (TAA1/TAR) genes that function in the tryptophan-dependent pathway of auxin biosynthesis. Sequence mining together with gene cloning identified 15 TaTAR genes, among which 12 and three genes were phylogenetically close to Arabidopsis ( Arabidopsis thaliana ) AtTAR2 and AtTAR3, respectively. TaTAR2.1 had the most abundant transcripts in the TaTAR2 genes and was expressed mainly in roots and up-regulated by low nitrogen (N) availability. Knockdown of TaTAR2.1 caused vegetative and reproductive deficiencies and impaired lateral root (LR) growth under both high- and low-N conditions. Overexpressing TaTAR2.1-3A in wheat enhanced LR branching, plant height, spike number, grain yield, and aerial N accumulation under different N supply levels. In addition, overexpressing TaTAR2.1-3A in Arabidopsis elevated auxin accumulation in the primary root tip, LR tip, LR primordia, and cotyledon and hypocotyl and increased primary root length, visible LR number, and shoot fresh weight under high- and low-N conditions. Our results indicate that TaTAR2.1 is critical for wheat growth and also shows potential for genetic engineering to reach the aim of improving the grain yield of wheat. © 2017 American Society of Plant Biologists. All Rights Reserved.

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

PubMed

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.

Partitioning studies of coal-tar constituents in a two-phase contaminated ground-water system

USGS Publications Warehouse

Rostad, C.E.; Pereira, W.E.; Hult, M.F.

1985-01-01

Organic compounds derived from coal-tar wastes in a contaminated aquifer in St. Louis Park, Minnesota, were identified, and their partition coefficients between the tar phase and aqueous phase were determined and compared with the corresponding n-octanol/water partition coefficients. Coal tar contains numerous polycyclic aromatic compounds, many of which are suspected carcinogens or mutagens. Groundwater contamination by these toxic compounds may pose an environmental health hazard in nearby public water-supply wells. Fluid samples from this aquifer developed two phases upon settling: an upper aqueous phase, and a lower oily-tar phase. After separating the phases, polycyclic aromatic compounds in each phase were isolated using complexation with N-methyl-2-pyrrolidone and identified by fused-silica capillary gas chromatography/mass spectrometry. Thirty-one of the polycyclic aromatic compounds were chosen for further study from four different classes: 12 polycyclic aromatic hydrocarbons, 10 nitrogen heterocycles, 5 sulfur heterocycles, and 4 oxygen heterocycles. Within each compound class, the tar/water partition coefficients of these compounds were reasonably comparable with the respective n-octanol/water partition coefficient.

Coal-tar-based sealcoated pavement: a major PAH source to urban stream sediments.

PubMed

Witter, Amy E; Nguyen, Minh H; Baidar, Sunil; Sak, Peter B

2014-02-01

We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (~1303 km(2)) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69-0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use. Copyright © 2013 Elsevier Ltd. All rights reserved.

Could Fluid Seeps Originate from the Seismogenic Zone? Evidence from Southern Costa Rica

NASA Astrophysics Data System (ADS)

Silver, E. A.; Kluesner, J. W.; Nale, S. M.; Bangs, N. L.; McIntosh, K. D.; Ranero, C. R.; Tryon, M. D.; Spinelli, G. A.; Rathburn, T.; von Huene, R.

2013-12-01

The prevailing conceptual model of convergent margin hydrogeology is one in which fluid sourced from porosity loss and dehydration reactions seaward of the updip limit of the seismogenic zone reach the seafloor via relatively low angle splay faults that act as high permeability conduits through an otherwise nearly impermeable upper plate [e.g., Lauer and Saffer, GRL, 39:L13604, 2012; Saffer and Tobin, Ann. Rev. Earth Planet. Sci., 39:157-186, 2011]. Interpretation of newly acquired 3D seismic reflection data and high resolvability multibeam and backscatter data, showing evidence for abundant potential fluid seeps sourced beneath the sediment cover and farther landward than previously thought possible, may require reevaluation of this concept. Kluesner et al. [2013, G3, doi:10.1002/ggge.20058], identified 160 potential fluid seeps in an 11 km wide swath off southern Costa Rica, based on pockmarks and high backscatter mounds, each showing subsurface indicators of fluid migration in the seismic data. Approximately half of these potential seeps are on the outer continental shelf; these are landward of the updip limit of the seismogenic zone, as estimated by both the transition from high to low reflectivity of the plate boundary and the intersection of the 150°C isotherm with the plate boundary [Ranero et al., 2008, G3, doi:10.1029/2007GC001679; Bangs et al., 2012, AGU Fall Meeting, T13A-2587; Bangs et al., this meeting]. We have mapped high probability fluid pathways beneath these potential seeps, based on seismic meta-attribute volumes calculated using user-trained neural network algorithms [Kluesner et al., this meeting]. The mapped fluid pathways are high-angle through the sedimentary section, and they root into basement highs and basement faults. Fluids could originate along the plate interface, where potential sources and pathways are known (Mid-slope sites: Hensen et al., 2004, Geology, 32:201-204), or above or below the interface, although sources from these

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

NASA Astrophysics Data System (ADS)

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

A photographic method for estimating wear of coal tar sealcoat from parking lots

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

Mateo Scoggins; Tom Ennis; Nathan Parker

2009-07-01

Coal-tar-based sealcoat has been recognized as an important source of PAHs to the environment through wear and transport via stormwater runoff. Sealcoat removal rates have not been measured or even estimated in the literature due to the complex array of physical and chemical process involved. A photographic study was conducted that incorporates all sources of wear using 10 coal tar-sealed parking lots in Austin, Texas, with sealcoat age ranging from 0 to 5 years. Randomly located photographs from each parking lot were analyzed digitally to quantify black sealed areas versus lighter colored unsealed areas at the pixel level. The resultsmore » indicate that coal tar sealcoat wears off of the driving areas of parking lots at a rate of approximately 4.7% per year, and from the parking areas of the lots at a rate of approximately 1.4% per year. The overall annual loss of sealcoat was calculated at 2.4%. This results in an annual delivery to the environment of 0.51 g of PAHs per m{sup 2} of coal tar-sealed parking lot. These values provide a more robust and much higher estimate of loading of PAHs from coal tar sealcoated parking lots when compared to other available measures. 20 refs., 6 figs.« less

Cold-seep ostracods from the western Svalbard margin: direct palaeo-indicator for methane seepage?

NASA Astrophysics Data System (ADS)

Yasuhara, Moriaki; Sztybor, Kamila; Rasmussen, Tine L.; Okahashi, Hisayo; Sato, Runa; Tanaka, Hayato

2018-01-01

Despite their high abundance and diversity, microfossil taxa adapted to a particular chemosynthetic environment have rarely been studied and are therefore poorly known. Here we report on an ostracod species, Rosaliella svalbardensis gen. et sp. nov., from a cold methane seep site at the western Svalbard margin, Fram Strait. The new species shows a distinct morphology, different from other eucytherurine ostracod genera. It has a marked similarity to Xylocythere, an ostracod genus known from chemosynthetic environments of wood falls and hydrothermal vents. Rosaliella svalbardensis is probably an endemic species or genus linked to methane seeps. We speculate that the surface ornamentation of pore clusters, secondary reticulation, and pit clusters may be related to ectosymbiosis with chemoautotrophic bacteria. This new discovery of specialized microfossil taxa is important because they can be used as an indicator species for past and present seep environments (http://zoobank.org/urn:lsid:zoobank.org:pub:6075FF30-29D5-4DAB-9141-AE722CD3A69B).

Carbon isotopes of benthic foraminifera associated with methane seeps in Four-Way Closure Ridge, offshore southwestern Taiwan

NASA Astrophysics Data System (ADS)

Wang, W. R.; Wei, K. Y.; Mii, H. S.; Lin, Y. S.; Huang, J. J.; Wang, P. L.; Lin, A. T.

2015-12-01

Release of large amounts of methane from marine gas hydrate reservoirs has been considered as a possible trigger of climate change, which can be recorded by the variation of carbon isotopes (δ13C) of the benthic foraminifera. In modern analogs, previous studies have suggested that δ13C becomes more negative when influenced by methane seeps. However, values of δ13C of benthic foraminifera might vary with different species and sedimentary settings in different regions. Seismic profiles in offshore southwestern Taiwan show the existence of Bottom Simulating Reflector (BSR) in the region, indicative of gas hydrate reservoirs. Various methane seepages have been found, and they are suspected to be related to the gas hydrates buried underneath. A better understanding of the δ13C signals of benthic foraminifera near the methane seepages can further clarify the origin of the methane and to evaluate it as a proxy of methane release for the geologic past. We have analyzed δ13C of benthic foraminifera Uvigerina proboscidea (150-250 mm) in the topmost 15 cm sediments in five marine cores (OR1-1092-WFWC-1, OR1-1092-WFWC-4, OR1-1092-WFWC-6, OR3-1806-C5-2 and OR3-1806-C10) collected from the Four-Way Closure Ridge in offshore southwestern Taiwan (water depth from 1330 to 1580 m). Our results show that δ13C values of U. proboscidea range from -0.98‰ to -6.21‰ (VPDB) for core OR3-1806-C5-2, which is considered as a seeps-influenced site. On the other hand, δ13C values of U. proboscidea from the background sites range from -0.40‰ to -1.00‰. The difference between the methane seep-affected and the background sites is in the range of 0.00‰ to 5.01‰, comparable to those documented in previous studies in other areas. The significant negative excursion in carbon isotopes in the seep site foraminifera is likely caused by incorporation of light inorganic carbon generated by methanotrophy in the system.

TarPmiR: a new approach for microRNA target site prediction.

PubMed

Ding, Jun; Li, Xiaoman; Hu, Haiyan

2016-09-15

The identification of microRNA (miRNA) target sites is fundamentally important for studying gene regulation. There are dozens of computational methods available for miRNA target site prediction. Despite their existence, we still cannot reliably identify miRNA target sites, partially due to our limited understanding of the characteristics of miRNA target sites. The recently published CLASH (crosslinking ligation and sequencing of hybrids) data provide an unprecedented opportunity to study the characteristics of miRNA target sites and improve miRNA target site prediction methods. Applying four different machine learning approaches to the CLASH data, we identified seven new features of miRNA target sites. Combining these new features with those commonly used by existing miRNA target prediction algorithms, we developed an approach called TarPmiR for miRNA target site prediction. Testing on two human and one mouse non-CLASH datasets, we showed that TarPmiR predicted more than 74.2% of true miRNA target sites in each dataset. Compared with three existing approaches, we demonstrated that TarPmiR is superior to these existing approaches in terms of better recall and better precision. The TarPmiR software is freely available at http://hulab.ucf.edu/research/projects/miRNA/TarPmiR/ CONTACTS: haihu@cs.ucf.edu or xiaoman@mail.ucf.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

Tar analysis from biomass gasification by means of online fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Baumhakl, Christoph; Karellas, Sotirios

2011-07-01

Optical methods in gas analysis are very valuable mainly due to their non-intrusive character. That gives the possibility to use them for in-situ or online measurements with only optical intervention in the measurement volume. In processes like the gasification of biomass, it is of high importance to monitor the gas quality in order to use the product gas in proper machines for energy production following the restrictions in the gas composition but also improving its quality, which leads to high efficient systems. One of the main problems in the biomass gasification process is the formation of tars. These higher hydrocarbons can lead to problems in the operation of the energy system. Up to date, the state of the art method used widely for the determination of tars is a standardized offline measurement system, the so-called "Tar Protocol". The aim of this work is to describe an innovative, online, optical method for determining the tar content of the product gas by means of fluorescence spectroscopy. This method uses optical sources and detectors that can be found in the market at low cost and therefore it is very attractive, especially for industrial applications where cost efficiency followed by medium to high precision are of high importance.

Aragonite precipitation induced by anaerobic oxidation of methane in shallow-water seeps, Tyrrhenian Sea, Italy

NASA Astrophysics Data System (ADS)

Wiedling, Johanna; Kuhfuß, Hanna; Lott, Christian; Böttcher, Michael E.; Lichtschlag, Anna; Wegener, Gunter; Deusner, Christian; Bach, Wolfgang; Weber, Miriam

2014-05-01

In the shallow-water organic-poor silicate sands off the West coast of Elba, Italy, we found aragonite precipitates within a radius of 10 cm to methane seeps in 20 - 40 cm sediment depth. The shallow seep site was mapped by SCUBA diving and in an area of 100 m2 nine gas emission spots were observed. The gas emission, containing 73 Vol. % methane, was measured to be 0.72 L m-2 d-1. Findings of anaerobic methane oxidizing archea (ANME 1, 2, 2a, 2b) and sulphate reducing bacteria (SRB) as well as in vitro rate measurements of anaerobic oxidation of methane (AOM) with a maximum of 67 ± 7 nmol CH4 cm-3 d-1 led to the hypothesis that carbonate precipitation is coupled to these microbial processes. Porewater analysis showed elevated concentrations of dissolved inorganic carbon (DIC) (up to 15.5 mmol L-1) and hydrogen sulfide (up to 6.6 mmol L-1). The presence of bicarbonate and the ambient temperature (14 - 25 ° C) facilitate the precipitation of needle-shaped aragonite. Oxygen isotope compositions of the mineral are consistent with the ambient temperatures and may indicate a recent diagenetic formation of this mineral. Although precipitation should not be preserved in these sandy permeable sediments, influenced by seasonality, wave action, and fluid flow, we found up to 10-50 cm3 irregular pieces of cemented sand grains, very often encrusting dead seagrass rhizomes. Commonly known carbonate structures, especially from the deep sea, are chimneys, mounds, hardgrounds and nodules. These structures are well known from seep and vent sites, usually showing the same range of stable carbon isotope fractionation as the escaping methane. The permeable sediment at the Elba site possibly allows the gas to frequently change its pathway to the sediment surface and thus precipitation can occure at several spots and more irregular than in the reported sites. Preservation of precipitates, however, requires sufficient authigenic aragonite to be formed before fluid dynamics changed the

The Microbial Ferrous Wheel in a Neutral pH Groundwater Seep

PubMed Central

Roden, Eric E.; McBeth, Joyce M.; Blöthe, Marco; Percak-Dennett, Elizabeth M.; Fleming, Emily J.; Holyoke, Rebecca R.; Luther, George W.; Emerson, David; Schieber, Juergen

2012-01-01

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. Most probable number enumerations detected microaerophilic Fe(II)-oxidizing bacteria (FeOB) and dissimilatory Fe(III)-reducing bacteria (FeRB) at densities of 102 to 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 with high 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

Modeling the impact of bubbling bed hydrodynamics on tar yield and its fluctuations during biomass fast pyrolysis

DOE PAGES

Xiong, Qingang; Ramirez, Emilio; Pannala, Sreekanth; ...

2015-10-09

The impact of bubbling bed hydrodynamics on temporal variations in the exit tar yield for biomass fast pyrolysis was investigated using computational simulations of an experimental laboratory-scale reactor. A multi-fluid computational fluid dynamics model was employed to simulate the differential conservation equations in the reactor, and this was combined with a multi-component, multi-step pyrolysis kinetics scheme for biomass to account for chemical reactions. The predicted mean tar yields at the reactor exit appear to match corresponding experimental observations. Parametric studies predicted that increasing the fluidization velocity should improve the mean tar yield but increase its temporal variations. Increases in themore » mean tar yield coincide with reducing the diameter of sand particles or increasing the initial sand bed height. However, trends in tar yield variability are more complex than the trends in mean yield. The standard deviation in tar yield reaches a maximum with changes in sand particle size. As a result, the standard deviation in tar yield increases with the increases in initial bed height in freely bubbling state, while reaches a maximum in slugging state.« less

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

PubMed Central

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 13C-depleted isotopic signatures of dissolved inorganic carbon. The anaerobic conversion of methane to CO2 was confirmed in a 13C-labeling experiment. Methane fueled a vital microbial community with cell numbers of up to 4 × 109 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. PMID:22207865

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

PubMed

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.

Activity and interactions of methane seep microorganisms assessed by parallel transcription and FISH-NanoSIMS analyses

DOE PAGES

Dekas, Anne E.; Connon, Stephanie A.; Chadwick, Grayson L.; ...

2015-09-22

To characterize the activity and interactions of methanotrophic archaea (ANME) and Deltaproteo-bacteria at a methane-seeping mud volcano, we used two complimentary measures of microbial activity: a community-level analysis of the transcription of four genes (16S rRNA, methyl coenzyme M reductase A (mcrA), adenosine-5'-phosphosulfate reductase α-subunit (aprA), dinitrogenase reductase (nifH)), and a single-cell-level analysis of anabolic activity using fluorescence in situ hybridization coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS). Transcript analysis revealed that members of the deltaproteobacterial groups Desulfosarcina/Desulfococcus (DSS) and Desulfobulbaceae (DSB) exhibit increased rRNA expression in incubations with methane, suggestive of ANME-coupled activity. Direct analysis of anabolic activity in DSS cells in consortia with ANME by FISH-NanoSIMS confirmed their dependence on methanotrophy, with no 15NHmore » $$+\\atop{4}$$ assimilation detected without methane. In contrast, DSS and DSB cells found physically independent of ANME (i.e., single cells) were anabolically active in incubations both with and without methane. These single cells therefore comprise an active ‘free-living’ population, and are not dependent on methane or ANME activity. We investigated the possibility of N 2 fixation by seep Deltaproteobacteria and detected nifH transcripts closely related to those of cultured diazotrophic Deltaproteobacteria. However, nifH expression was methane-dependent. 15N 2 incorporation was not observed in single DSS cells, but was detected in single DSB cells. Interestingly, 15N 2 incorporation in single DSB cells was methane-dependent, raising the possibility that DSB cells acquired reduced 15N products from diazotrophic ANME while spatially coupled, and then subsequently dissociated. In conclusion, with this combined data set we address several outstanding questions in methane seep microbial ecosystems and highlight the benefit

Activity and interactions of methane seep microorganisms assessed by parallel transcription and FISH-NanoSIMS analyses

PubMed Central

Dekas, Anne E; Connon, Stephanie A; Chadwick, Grayson L; Trembath-Reichert, Elizabeth; Orphan, Victoria J

2016-01-01

To characterize the activity and interactions of methanotrophic archaea (ANME) and Deltaproteobacteria at a methane-seeping mud volcano, we used two complimentary measures of microbial activity: a community-level analysis of the transcription of four genes (16S rRNA, methyl coenzyme M reductase A (mcrA), adenosine-5′-phosphosulfate reductase α-subunit (aprA), dinitrogenase reductase (nifH)), and a single-cell-level analysis of anabolic activity using fluorescence in situ hybridization coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS). Transcript analysis revealed that members of the deltaproteobacterial groups Desulfosarcina/Desulfococcus (DSS) and Desulfobulbaceae (DSB) exhibit increased rRNA expression in incubations with methane, suggestive of ANME-coupled activity. Direct analysis of anabolic activity in DSS cells in consortia with ANME by FISH-NanoSIMS confirmed their dependence on methanotrophy, with no 15NH4+ assimilation detected without methane. In contrast, DSS and DSB cells found physically independent of ANME (i.e., single cells) were anabolically active in incubations both with and without methane. These single cells therefore comprise an active ‘free-living' population, and are not dependent on methane or ANME activity. We investigated the possibility of N2 fixation by seep Deltaproteobacteria and detected nifH transcripts closely related to those of cultured diazotrophic Deltaproteobacteria. However, nifH expression was methane-dependent. 15N2 incorporation was not observed in single DSS cells, but was detected in single DSB cells. Interestingly, 15N2 incorporation in single DSB cells was methane-dependent, raising the possibility that DSB cells acquired reduced 15N products from diazotrophic ANME while spatially coupled, and then subsequently dissociated. With this combined data set we address several outstanding questions in methane seep microbial ecosystems and highlight the benefit of measuring microbial activity in the

Genetic legacy of the deep subsurface recorded in the outflow channel of a terrestrial serpentinizing seep (Luzon, the Philippines)

NASA Astrophysics Data System (ADS)

Woycheese, K. M.; Meyer-Dombard, D. R.; Cardace, D.; Arcilla, C. A.

2014-12-01

). The DOC concentration at PB1 main pool was 0.3 ppm and 1.15 ppm at PB2. Given the low DIC concentrations at PB1, it is suggested that heterotrophy may dominate over autotrophy in the system. This suggests that the highly reducing, high pH fluids emanating from fluid seeps at Poon Bato influence surface communities via inundation with serpentinizing fluid.

Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement

USGS Publications Warehouse

Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

2012-01-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (ΣPAH8) in the 0.03-m samples above sealed lots (1320 ng m-3) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m-3). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m-3) was five times greater than above unsealed lots (26.0 ng m-3). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 μg m-2 h-1, respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces.

Iron(II) supramolecular helicates interfere with the HIV-1 Tat–TAR RNA interaction critical for viral replication

PubMed Central

Malina, Jaroslav; Hannon, Michael J.; Brabec, Viktor

2016-01-01

The interaction between the HIV-1 transactivator protein Tat and TAR (transactivation responsive region) RNA, plays a critical role in HIV-1 transcription. Iron(II) supramolecular helicates were evaluated for their in vitro activity to inhibit Tat–TAR RNA interaction using UV melting studies, electrophoretic mobility shift assay, and RNase A footprinting. The results demonstrate that iron(II) supramolecular helicates inhibit Tat-TAR interaction at nanomolar concentrations by binding to TAR RNA. These studies provide a new insight into the biological potential of metallosupramolecular helicates. PMID:27405089

Iron(II) supramolecular helicates interfere with the HIV-1 Tat-TAR RNA interaction critical for viral replication.

PubMed

Malina, Jaroslav; Hannon, Michael J; Brabec, Viktor

2016-07-12

The interaction between the HIV-1 transactivator protein Tat and TAR (transactivation responsive region) RNA, plays a critical role in HIV-1 transcription. Iron(II) supramolecular helicates were evaluated for their in vitro activity to inhibit Tat-TAR RNA interaction using UV melting studies, electrophoretic mobility shift assay, and RNase A footprinting. The results demonstrate that iron(II) supramolecular helicates inhibit Tat-TAR interaction at nanomolar concentrations by binding to TAR RNA. These studies provide a new insight into the biological potential of metallosupramolecular helicates.

Symbiont-driven sulfur crystal formation in a thiotrophic symbiosis from deep-sea hydrocarbon seeps

PubMed Central

Eichinger, Irmgard; Schmitz-Esser, Stephan; Schmid, Markus; Fisher, Charles R; Bright, Monika

2014-01-01

The siboglinid tubeworm Sclerolinum contortum symbiosis inhabits sulfidic sediments at deep-sea hydrocarbon seeps in the Gulf of Mexico. A single symbiont phylotype in the symbiont-housing organ is inferred from phylogenetic analyses of the 16S ribosomal ribonucleic acid (16S rRNA) gene and fluorescent in situ hybridization. The phylotype we studied here, and a previous study from an arctic hydrocarbon seep population, reveal identical 16S rRNA symbiont gene sequences. While sulfide is apparently the energy source for the symbionts (and ultimately the gutless host), both partners also have to cope with its toxicity. This study demonstrates abundant large sulfur crystals restricted to the trophosome area. Based on Raman microspectroscopy and energy dispersive X-ray analysis, these crystals have the same S8 sulfur configuration as the recently described small sulfur vesicles formed in the symbionts. The crystals reside adjacent to the symbionts in the trophosome. This suggests that their formation is either extra- or intracellular in symbionts. We propose that formation of these crystals provides both energy-storage compounds for the symbionts and serves the symbiosis by removing excess toxic sulfide from host tissues. This symbiont-mediated sulfide detoxification may have been crucial for the establishment of thiotrophic symbiosis and continues to remain an important function of the symbionts. PMID:24992535

Possible roles of uncultured archaea in carbon cycling in methane-seep sediments

NASA Astrophysics Data System (ADS)

Yoshinaga, Marcos Y.; Lazar, Cassandre S.; Elvert, Marcus; Lin, Yu-Shih; Zhu, Chun; Heuer, Verena B.; Teske, Andreas; Hinrichs, Kai-Uwe

2015-09-01

Studies on microbial carbon cycling uniformly confirm that anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria represent the dominant and most active fraction of the sedimentary microbial community in methane-seep sediments. However, little is known about other frequently observed and abundant microbial taxa, their role in carbon cycling and association with the anaerobic oxidation of methane (AOM). Here, we provide a comprehensive characterization of stable carbon isotopes (δ13C) from several intact polar lipid (IPL) classes and metabolite pools in a downcore profile at a cold seep within the oxygen minimum zone off Pakistan. We aimed to evaluate microbial carbon metabolism using IPLs in relation to redox conditions, metabolites and 16S rRNA gene libraries. The 13C-depleted signature of carbon pools and microbial metabolites in pore waters (e.g., dissolved inorganic carbon, lactate and acetate) demonstrated high accumulation of AOM-associated biomass and subsequent turnover thereof. ANMEs accounted for a small fraction of the archaeal 16S rRNA gene survey, whereas sequences of other uncultured benthic archaea dominated the clone libraries, particularly the Marine Benthic Group D. On the basis of lipid diversity and carbon isotope information, we suggest that structurally diverse phospho- and glycolipids, including the recently identified unsaturated tetraethers that are particularly abundant in this setting, are likely derived from archaea other than ANMEs. Through the evaluation of δ13C values of individual IPL, our results indicate heterotrophy as a possible metabolic pathway of archaea in these AOM-dominated sediments.

The impact of steam and current density on carbon formation from biomass gasification tar on Ni/YSZ, and Ni/CGO solid oxide fuel cell anodes

NASA Astrophysics Data System (ADS)

Mermelstein, Joshua; Millan, Marcos; Brandon, Nigel

The combination of solid oxide fuel cells (SOFCs) and biomass gasification has the potential to become an attractive technology for the production of clean renewable energy. However the impact of tars, formed during biomass gasification, on the performance and durability of SOFC anodes has not been well established experimentally. This paper reports an experimental study on the mitigation of carbon formation arising from the exposure of the commonly used Ni/YSZ (yttria stabilized zirconia) and Ni/CGO (gadolinium-doped ceria) SOFC anodes to biomass gasification tars. Carbon formation and cell degradation was reduced through means of steam reforming of the tar over the nickel anode, and partial oxidation of benzene model tar via the transport of oxygen ions to the anode while operating the fuel cell under load. Thermodynamic calculations suggest that a threshold current density of 365 mA cm -2 was required to suppress carbon formation in dry conditions, which was consistent with the results of experiments conducted in this study. The importance of both anode microstructure and composition towards carbon deposition was seen in the comparison of Ni/YSZ and Ni/CGO anodes exposed to the biomass gasification tar. Under steam concentrations greater than the thermodynamic threshold for carbon deposition, Ni/YSZ anodes still exhibited cell degradation, as shown by increased polarization resistances, and carbon formation was seen using SEM imaging. Ni/CGO anodes were found to be more resilient to carbon formation than Ni/YSZ anodes, and displayed increased performance after each subsequent exposure to tar, likely due to continued reforming of condensed tar on the anode.

Crystallization and preliminary X-ray diffraction analysis of the periplasmic domain of the Escherichia coli aspartate receptor Tar and its complex with aspartate

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

Mise, Takeshi; Matsunami, Hideyuki; Samatey, Fadel A.

The periplasmic domain of the E. coli aspartate receptor Tar was cloned, expressed, purified and crystallized with and without bound ligand. The crystals obtained diffracted to resolutions of 1.58 and 1.95 Å, respectively. The cell-surface receptor Tar mediates bacterial chemotaxis toward an attractant, aspartate (Asp), and away from a repellent, Ni{sup 2+}. To understand the molecular mechanisms underlying the induction of Tar activity by its ligands, the Escherichia coli Tar periplasmic domain with and without bound aspartate (Asp-Tar and apo-Tar, respectively) were each crystallized in two different forms. Using ammonium sulfate as a precipitant, crystals of apo-Tar1 and Asp-Tar1 weremore » grown and diffracted to resolutions of 2.10 and 2.40 Å, respectively. Alternatively, using sodium chloride as a precipitant, crystals of apo-Tar2 and Asp-Tar2 were grown and diffracted to resolutions of 1.95 and 1.58 Å, respectively. Crystals of apo-Tar1 and Asp-Tar1 adopted space group P4{sub 1}2{sub 1}2, while those of apo-Tar2 and Asp-Tar2 adopted space groups P2{sub 1}2{sub 1}2{sub 1} and C2, respectively.« less

Microbial sulfate reduction rates and sulfur and oxygen isotope fractionations at oil and gas seeps in deepwater Gulf of Mexico

NASA Astrophysics Data System (ADS)

Aharon, Paul; Fu, Baoshun

2000-01-01

Sulfate reduction and anaerobic methane oxidation are the dominant microbial processes occurring in hydrate-bearing sediments at bathyal depths in the Gulf of Mexico where crude oil and methane are advecting through fault conduits to the seafloor. The oil and gas seeps are typically overlain by chemosynthetic communities consisting of thiotrophic bacterial mats (Beggiatoa spp.) and methanotrophic mussels (Bathymodiolus spp.), respectively. Cores were recovered with a manned submersible from fine-grained sediments containing dispersed gas hydrates at the threshold of stability. Estimated sulfate reduction rates are variable but generally are substantially higher in crude oil seeps (up to 50 times) and methane seeps (up to 600 times) relative to a non-seep reference sediment (0.0043 μmol SO 42- cm -3 day -1). Sulfur and oxygen isotope fractionation factors are highest in the reference sediment (α S = 1.027; α O = 1.015) but substantially lower in the seep sediments (α S = 1.018 to 1.009; α O = 1.006 to 1.002) and are controlled primarily by kinetic factors related to sulfate reduction rates. Kinetic effects also control the δ 34S/δ 18O ratios such that slow microbial rates yield low ratios whereas faster rates yield progressively higher ratios. The seep data contradict previous claims that δ 34S/δ 18O ratios are diagnostic of either microbial sulfate reduction at a fixed δ 34S/δ 18O ratio of 4/1 or lower ratios caused by SO 4-H 2O equilibration at ambient temperatures. The new results offer a better understanding of methane removal via anaerobic oxidation in the sulfate reduction zone of hydrate-bearing sediments and have significant implications regarding the origin and geochemical history of sedimentary sulfate reconstructed on the basis of δ 34S and δ 18O compositions.

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

NASA Astrophysics Data System (ADS)

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

Potential contributions of asphalt and coal tar to black carbon quantification in urban dust, soils, and sediments

USGS Publications Warehouse

Yang, Y.; Mahler, B.J.; Van Metre, P.C.; Ligouis, B.; Werth, C.J.

2010-01-01

Measurements of black carbon (BC) using either chemical or thermal oxidation methods are generally thought to indicate the amount of char and/or soot present in a sample. In urban environments, however, asphalt and coal-tar particles worn from pavement are ubiquitous and, because of their pyrogenic origin, could contribute to measurements of BC. Here we explored the effect of the presence of asphalt and coal-tar particles on the quantification of BC in a range of urban environmental sample types, and evaluated biases in the different methods used for quantifying BC. Samples evaluated were pavement dust, residential and commercial area soils, lake sediments from a small urban watershed, and reference materials of asphalt and coal tar. Total BC was quantified using chemical treatment through acid dichromate (Cr2O7) oxidation and chemo-thermal oxidation at 375??C (CTO-375). BC species, including soot and char/charcoal, asphalt, and coal tar, were quantified with organic petrographic analysis. Comparison of results by the two oxidation methods and organic petrography indicates that both coal tar and asphalt contribute to BC quantified by Cr2O7 oxidation, and that coal tar contributes to BC quantified by CTO-375. These results are supported by treatment of asphalt and coal-tar reference samples with Cr2O7 oxidation and CTO-375. The reference asphalt is resistant to Cr2O7 oxidation but not to CTO-375, and the reference coal tar is resistant to both Cr2O7 oxidation and CTO-375. These results indicate that coal tar and/or asphalt can contribute to BC measurements in samples from urban areas using Cr2O7 oxidation or CTO-375, and caution is advised when interpreting BC measurements made with these methods. ?? 2010 Elsevier Ltd.

A comparison of physicochemical methods for the remediation of porous medium systems contaminated with tar

NASA Astrophysics Data System (ADS)

Hauswirth, Scott C.; Miller, Cass T.

2014-10-01

The remediation of former manufactured gas plant (FMGP) sites contaminated with tar DNAPLs (dense non-aqueous phase liquids) presents a significant challenge. The tars are viscous mixtures of thousands of individual compounds, including known and suspected carcinogens. This work investigates the use of combinations of mobilization, solubilization, and chemical oxidation approaches to remove and degrade tars and tar components in porous medium systems. Column experiments were conducted using several flushing solutions, including an alkaline-polymer (AP) solution containing NaOH and xanthan gum (XG), a surfactant-polymer (SP) solution containing Triton X-100 surfactant (TX100) and XG, an alkaline-surfactant-polymer (ASP) solution containing NaOH, TX100, and XG, and base-activated sodium persulfate both with and without added TX100. The effectiveness of the flushing solutions was assessed based on both removal of polycyclic aromatic hydrocarbon (PAH) mass and on the reduction of dissolved-phase PAH concentrations. SP flushes of 6.6 to 20.9 PV removed over 99% of residual PAH mass and reduced dissolved-phase concentrations by up to two orders of magnitude. ASP flushing efficiently removed 95-96% of residual PAH mass within about 2 PV, and significantly reduced dissolved-phase concentrations of several low molar mass compounds, including naphthalene, acenaphthene, fluorene, and phenanthrene. AP flushing removed a large portion of the residual tar (77%), but was considerably less effective than SP and ASP in terms of the effect on dissolved PAH concentrations. Persulfate was shown to oxidize tar components, primarily those with low molar mass, however, the overall degradation was relatively low (30-50% in columns with low initial tar saturations), and the impact on dissolved-phase concentrations was minimal.

Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement.

PubMed

Van Metre, Peter C; Majewski, Michael S; Mahler, Barbara J; Foreman, William T; Braun, Christopher L; Wilson, Jennifer T; Burbank, Teresa L

2012-06-01

Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (ΣPAH(8)) in the 0.03-m samples above sealed lots (1320 ng m(-3)) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m(-3)). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m(-3)) was five times greater than above unsealed lots (26.0 ng m(-3)). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 μg m(-2) h(-1), respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces. Published by Elsevier Ltd.

Offshore springs and seeps are focus of working group

NASA Astrophysics Data System (ADS)

Burnett, Bill

People have been curious about offshore springs and seeps since at least the days of the Romans. In spite of many centuries of both casual and serious observations, there has been relatively little scientific study concerning the magnitude and effects of groundwater flow into the sea. Rather, studies were performed mostly to address water resource issues. Investigations over the past decade or so have now shown that groundwater discharge, at least in some cases, may be important for geochemical budgets and ecological effects.The Scientific Committee on Oceanic Research (SCOR) and the Land-Ocean Interactions in the Coastal Zone (LOICZ) Project of the International Geosphere-Biosphere Program have recently established a working group of experts to examine questions relating specifically to groundwater discharge in the coastal zone. Direct groundwater flow into the ocean is known to occur as springs and seeps in near-shore areas in many parts of the world. Submarine springs, for example, are well known off both coasts of Florida; Mexico's Yucatan Peninsula; in several areas around the Pacific rim including Chile, Hawaii, Guam, American Samoa, and Australia; in the Persian Gulf near Bahrain; in the Mediterranean Sea off Spain, France, Italy, Greece, Syria, Lebanon, Israel, and Libya; and in many other locations.

Development of secondary chamber for tar cracking-improvement of wood pyrolysis performance in pre-vacuum chamber

NASA Astrophysics Data System (ADS)

Siahaan, S.; Homma, H.; Homma, H.

2018-02-01

Energy crisis and global warming, in other words, climate change are critical topics discussed in various parts of the world. Global warming primarily result from too much emission of carbon dioxide (CO2) in the atmosphere. To mitigate global warming, or climate change and improve electrification in rural areas, wood pyrolysis technology is developed in a laboratory scale, of which gases are directly applicable to the gas engine generator. Our laboratory has developed a prototype of wood pyrolysis plant with a pre-vacuum chamber. However, tar yield was around 40 wt% of feedstock. This research aims to reduce tar yield by secondary tar cracking. For the secondary tar cracking, a secondary pre-vacuum chamber is installed after primary pre-vacuum chamber. Gases generated in the primary pre-vacuum chamber are lead into the secondary chamber that is heated up to 1000 K. This paper reports performance of the secondary chamber for secondary tar cracking in homogeneous mode and heterogeneous mode with char.

Fluid geochemistry of cold seeps and hydrothermal vents in the Guaymas Basin, Gulf of California

NASA Astrophysics Data System (ADS)

Hensen, Christian; Geilert, Sonja; Scholz, Florian; Schmidt, Mark; Liebetrau, Volker; Kipfer, Rolf; Sarkar, Sudipta; Doll, Mechthild

2017-04-01

In this study, we present geochemical data from pore fluids and gases that were sampled at cold seeps and hydrothermal vents in the Guaymas Basin during Sonne cruise 241. The Guaymas Basin is a unique environment where magma intrudes into thick sequences of organic-rich sediments, thereby maturing host rocks and releasing large amounts of hydrocarbons. Geochemical measurements performed on samples from a recently discovered high-temperature vent field (Berndt et al., 2016) clearly support this paradigm. 3He/4He ratios agree with that of excess He from the southern part of the Guaymas Basin (Lupton, 1979) and suggest the same general MORB source, while isotopic data of hydrocarbon gases largely indicate a thermogenic, sedimentary source. Heat flow measurements performed in the vicinity of the smoker site are extremely high, exceeding 10 W/m2, indicating that hydrocarbon gas production (mainly CH4) is related to contact heating due to magmatic activity near the hydrothermal vents. Cold seeps are located up to some tens of kilometres off the rift axis and are typically characterized by chemosynthetic fauna assemblages at the seafloor. The occurrence of the seeps has also been related to sill intrusions. Seismic records typically show evidence for sediment mobilization in the deeper subsurface and blanked zones due to gas accumulations directly beneath the seeps. Despite these visual and geophysical indications for deep-sourced heat-driven fluid flow, pore water data are not indicative for geochemical reactions taking place at elevated temperatures. Major dissolved constituents do not show strong deviations from seawater and dissolved methane is typically of biogenic origin. In addition, heat flow values do not deviate from regional averages, and hence, these findings contradict the existing hypothesis of a sill-driven mechanism responsible for the formation of seafloor seepage sites. A preliminary interpretation is that fluid and gas mobilisation from sill activity

PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States.

PubMed

Van Metre, Peter C; Mahler, Barbara J; Wilson, Jennifer T

2009-01-01

We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U.S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat. Dust was swept from parking lots in six cities in the central and eastern U.S., where coal-tar-based sealcoat dominates use, and three cities in the western U.S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median SigmaPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median SigmaPAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2.1 and 0.8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dustfrom coal-tarsealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

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

NASA Astrophysics Data System (ADS)

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.

Contribution of deep sourced carbon from hydrocarbon seeps to sedimentary organic carbon: Evidence from Δ14C and δ13C isotopes

NASA Astrophysics Data System (ADS)

Feng, D.; Peckmann, J.; Peng, Y.; Liang, Q.; Roberts, H. H.; Chen, D.

2017-12-01

Sulfate-driven anaerobic oxidation of methane (AOM) limits the release of methane from marine sediments and promotes the formation of carbonates close to the seafloor along continental margins. It has been established that hydrocarbon seeps are a source of dissolved inorganic and organic carbon to marine environments. However, questions remain about the contribution of deep sourced carbon from hydrocarbon seeps to the sedimentary organic carbon pool. For a number of hydrocarbon seeps from the South China Sea and the Gulf of Mexico, the portion of modern carbon was determined based on natural radiocarbon abundances (Δ14C) and stable carbon isotope (δ13Corganic carbon) compositions of the non-carbonate fractions extracted from authigenic carbonates. Samples from both areas show a mixing trend between ideal planktonic organic carbon (δ13C = -22‰ VPDB and 90% modern carbon) and the ambient methane. The δ13Corganic carbon values of non-carbonate fractions from three ancient seep deposits (northern Italy, Miocene; western Washington State, USA, Eocene to Oligocene) confirm that the proxy can be used to constrain the record of sulfate-driven AOM through most of Earth history by measuring the δ13C values of organic carbon. This study reveals the potential of using δ13C values of organic carbon to discern seep and non-seep environments. This new approach is particularly promising when authigenic carbonate is not present in ancient sedimentary environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support of the deep-sea dives. Funding was provided by the NSF of China (Grants: 41422602 and 41373085).

Horizontal Transfer of phnAc Dioxygenase Genes within One of Two Phenotypically and Genotypically Distinctive Naphthalene-Degrading Guilds from Adjacent Soil Environments

PubMed Central

Wilson, Mark S.; Herrick, James B.; Jeon, Che Ok; Hinman, David E.; Madsen, Eugene L.

2003-01-01

Several distinct naphthalene dioxygenases have been characterized to date, which provides the opportunity to investigate the ecological significance, relative distribution, and transmission modes of the different analogs. In this study, we showed that a group of naphthalene-degrading isolates from a polycyclic aromatic hydrocarbon (PAH)-contaminated hillside soil were phenotypically and genotypically distinct from naphthalene-degrading organisms isolated from adjacent, more highly contaminated seep sediments. Mineralization of 14C-labeled naphthalene by soil slurries suggested that the in situ seep community was more acclimated to PAHs than was the in situ hillside community. phnAc-like genes were present in diverse naphthalene-degrading isolates cultured from the hillside soil, while nahAc-like genes were found only among isolates cultured from the seep sediments. The presence of a highly conserved nahAc allele among gram-negative isolates from the coal tar-contaminated seep area provided evidence for in situ horizontal gene transfer and was reported previously (J. B. Herrick, K. G. Stuart-Keil, W. C. Ghiorse, and E. L. Madsen, Appl. Environ. Microbiol. 63:2330-2337, 1997). Natural horizontal transfer of the phnAc sequence was also suggested by a comparison of the phnAc and 16S ribosomal DNA sequences of the hillside isolates. Analysis of metabolites produced by cell suspensions and patterns of amplicons produced by PCR analysis suggested both genetic and metabolic diversity among the naphthalene-degrading isolates of the contaminated hillside. These results provide new insights into the distribution, diversity, and transfer of phnAc alleles and increase our understanding of the acclimation of microbial communities to pollutants. PMID:12676698

Optical, Physical and Chemical Properties of Tar Balls Observed During the Yosemite Aerosol Characterization Study

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

Hand, Jenny L.; Malm, W. C.; Laskin, Alexander

2005-11-09

The Yosemite Aerosol Characterization Study of summer 2002 (YACS) occurred during an active fire season in the western U. S., and provided an opportunity to investigate many unresolved issues related to the radiative effects of biomass burning aerosols. Single particle analysis was performed on field collected aerosol samples using an array of electron microscopy techniques. Amorphous carbon spheres, or “tar balls”, were present in samples collected during episodes of high particle light scattering coefficients that occurred during the peak of a smoke/haze event. The highest concentrations of light-absorbing carbon from a dual-wavelength aethalometer (λ = 370 and 880 nm) occurredmore » during periods when the particles were predominantly tar balls, indicating they do absorb light in the UV and near-IR range of the solar spectrum. Closure experiments of mass concentrations and light scattering coefficients during periods dominated by tar balls did not require any distinct assumptions of organic carbon molecular weight correction factors, density, or refractive index compared to periods dominated by other types of organic carbon aerosols. Measurements of the hygroscopic behavior of tar balls using an environmental SEM indicate that tar balls do not exhibit deliquescence, but do uptake some water at high (~83 %) relative humidity. The ability of tar balls to efficiently scatter and absorb light, and to absorb water has important implications for their role in regional haze and climate fence.« less

Comparative evaluation of topical calcipotriol versus coal tar and salicylic acid ointment in chronic plaque psoriasis.

PubMed

Singh, Preeti; Gupta, Surabhi; Abidi, Afroz; Krishna, Arvind

2013-08-01

Calcipotriol is a newer topical treatment option available for plaque psoriasis and coal tar being one of the oldest treatment and still in use. To evaluate and compare the differences in terms of efficacy, safety and relapse with Calcipotriol 0.005% (50 mcg/gm) and 6% coal tar and 3% salicylic ointment in patients with Plaque psoriasis. SETTING and Study conducted on 60 patients of plaque psoriasis, who attended the skin OPD in our hospital. The patients with mild to moderate plaque psoriasis were selected. 60 patients were enrolled for the study after obtaining informed consent. Subjects were asked to apply Calcipotriol 0.005% (50 mcg/gm) (Heximar Win care) twice a day on the right side plaques and on left side plaques, Petroleum jelly (Vaseline) in the morning and 6% coal tar and 3% salicylic ointment (Protar® Percos) at nighttime. PASI score was used to assess the reponse to therapy at 2nd, 4th, 6th and 8th week. After treatment subjects were observed for 6 weeks for any relapse. It was done by paired t-test and independent sample t-test. The results showed that statistically significant difference was seen in the mean percentage reduction of PASI score between both the groups, at all the assessment visits, 2, 4, 6, and 8 weeks, the mean percentage reduction at 2 weeks for calcipotriol being 21±12.06 and for coal tar being 13.44±11.19 (P=0.000), at 4 weeks for calcipotriol was 40±16.71 and for coal tar 25±99 (P=0.000), at 6 weeks for calcipotriol was 53.99+-22.43 and for coal tar 41±21.23 (P=0.002), at 8 weeks for calcipotriol was 62.73±24.04 and for coal tar was 51.53±23.27 (P=0.11). Relapse was seen in 5/60 (8.3%) of patients on calcipotriol treated side and 9/60 (15%) of patients with coal tar treated side. Thus it can be concluded that calcipotriol cream is more efficacious when compared with coal tar and does have a quick response. It is well tolerated and acceptable cosmetically.

Selected constituents in the smokes of U. S. commercial cigaretts: tar, nicotine, carbon monoxide and carbon dioxide

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

Jenkins, R.A.; Quincy, R.B.; Guerin, M.R.

One hundred twenty-one brands of United States commercial cigarettes were analyzed for their deliveries of tar, nicotine, carbon monoxide, and carbon dioxide under standard analytical smoking conditions. The sample included both filter and nonfilter cigarettes. Comparisons of carbon monoxide deliveries over the range of observed tar deliveries indicated a very high correlation between CO and tar for filter cigarettes, but nonfilter cigarettes tended to produce much less CO than would have been predicted from their tar deliveries. Comparison of ORNL nicotine values for specific brands with those determined by the Federal Trade Commission yield no statistically significant differences between laboratories.more » 4 figures, 6 tables.« less

Do increases in cigarette prices lead to increases in sales of cigarettes with high tar and nicotine yields?

PubMed

Farrelly, Matthew C; Loomis, Brett R; Mann, Nathan H

2007-10-01

We used scanner data on cigarette prices and sales collected from supermarkets across the United States from 1994 to 2004 to test the hypothesis that cigarette prices are positively correlated with sales of cigarettes with higher tar and nicotine content. During this period the average inflation-adjusted price for menthol cigarettes increased 55.8%. Price elasticities from multivariate regression models suggest that this price increase led to an increase of 1.73% in sales-weighted average tar yields and a 1.28% increase in sales-weighted average nicotine yields for menthol cigarettes. The 50.5% price increase of nonmenthol varieties over the same period yielded an estimated increase of 1% in tar per cigarette but no statistically significant increase in nicotine yields. An ordered probit model of the impact of cigarette prices on cigarette strength (ultra-light, light, full flavor, unfiltered) offers an explanation: As cigarette prices increase, the probability that stronger cigarette types will be sold increases. This effect is larger for menthol than for nonmenthol cigarettes. Our results are consistent with earlier population-based cross-sectional and longitudinal studies showing that higher cigarette prices and taxes are associated with increasing consumption of higher-yield cigarettes by smokers.

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

PubMed Central

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

Ligand-induced changes in 2-aminopurine fluorescence as a probe for small molecule binding to HIV-1 TAR RNA

PubMed Central

BRADRICK, THOMAS D.; MARINO, JOHN P.

2004-01-01

Replication of human immunodeficiency virus type 1 (HIV-1) is regulated in part through an interaction between the virally encoded trans-activator protein Tat and the trans-activator responsive region (TAR) of the viral RNA genome. Because TAR is highly conserved and its interaction with Tat is required for efficient viral replication, it has received much attention as an antiviral drug target. Here, we report a 2-aminopurine (2-AP) fluorescence-based assay for evaluating potential TAR inhibitors. Through selective incorporation of 2-AP within the bulge (C23 or U24) of a truncated form of the TAR sequence (Δ TAR-ap23 and Δ TAR-ap24), binding of argininamide, a 24-residue arginine-rich peptide derived from Tat, and Neomycin has been characterized using steady-state fluorescence. Binding of argininamide to the 2-AP ΔTAR constructs results in a four- to 11-fold increase in fluorescence intensity, thus providing a sensitive reporter of that interaction (KD ~ 1 mM). Similarly, binding of the Tat peptide results in an initial 14-fold increase in fluorescence (KD ~ 25 nM), but is then followed by a slight decrease that is attributed to an additional, lower-affinity association(s). Using the ΔTAR-ap23 and TAR-ap24 constructs, two classes of Neomycin binding sites are detected; the first molecule of antibiotic binds as a noncompetitive inhibitor of Tat/argininamide (KD ~ 200 nM), whereas the second, more weakly bound molecule(s) becomes associated in a presumably nonspecific manner (KD ~ 4 μM). Taken together, the results demonstrate that the 2-AP fluorescence-detected binding assays provide accurate and general methods for quantitatively assessing TAR interactions. PMID:15273324

Structural determinants of HIV-1 nucleocapsid protein for cTAR DNA binding and destabilization, and correlation with inhibition of self-primed DNA synthesis.

PubMed

Beltz, Hervé; Clauss, Céline; Piémont, Etienne; Ficheux, Damien; Gorelick, Robert J; Roques, Bernard; Gabus, Caroline; Darlix, Jean-Luc; de Rocquigny, Hugues; Mély, Yves

2005-05-20

The nucleocapsid protein (NC) of human immunodeficiency virus type 1 (HIV-1) is formed of two highly conserved CCHC zinc fingers flanked by small basic domains. NC is required for the two obligatory strand transfers in viral DNA synthesis through its nucleic acid chaperoning properties. The first DNA strand transfer relies on NC's ability to bind and destabilize the secondary structure of complementary transactivation response region (cTAR) DNA, to inhibit self-priming, and to promote the annealing of cTAR to TAR RNA. To further investigate NC chaperone properties, our aim was to identify by fluorescence spectroscopy and gel electrophoresis, the NC structural determinants for cTAR binding and destabilization, and for the inhibition of self-primed DNA synthesis on a model system using a series of NC mutants and HIV-1 reverse transcriptase. NC destabilization and self-priming inhibition properties were found to be supported by the two fingers in their proper context and the basic (29)RAPRKKG(35) linker. The strict requirement of the native proximal finger suggests that its hydrophobic platform (Val13, Phe16, Thr24 and Ala25) is crucial for binding, destabilization and inhibition of self-priming. In contrast, only partial folding of the distal finger is required, probably for presenting the Trp37 residue in an appropriate orientation. Also, Trp37 and the hydrophobic residues of the proximal finger appear to be essential for the propagation of the melting from the cTAR ends up to the middle of the stem. Finally, both N-terminal and C-terminal basic domains contribute to cTAR binding but not to its destabilization.

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

PubMed

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 δ(13)C, δ(15)N, and δ(34)S 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 δ(13)C 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. δ(34)S values were extremely variable among individuals of the same species within one location (<1 m(2) 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 δ(15)N 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.

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

NASA Astrophysics Data System (ADS)

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.

Pyrolysis of aseptic packages (tetrapak) in a laboratory screw type reactor and secondary thermal/catalytic tar decomposition.

PubMed

Haydary, J; Susa, D; Dudáš, J

2013-05-01

Pyrolysis of aseptic packages (tetrapak cartons) in a laboratory apparatus using a flow screw type reactor and a secondary catalytic reactor for tar cracking was studied. The pyrolysis experiments were realized at temperatures ranging from 650 °C to 850 °C aimed at maximizing of the amount of the gas product and reducing its tar content. Distribution of tetrapak into the product yields at different conditions was obtained. The presence of H2, CO, CH4, CO2 and light hydrocarbons, HCx, in the gas product was observed. The Aluminum foil was easily separated from the solid product. The rest part of char was characterized by proximate and elemental analysis and calorimetric measurements. The total organic carbon in the tar product was estimated by elemental analysis of tars. Two types of catalysts (dolomite and red clay marked AFRC) were used for catalytic thermal tar decomposition. Three series of experiments (without catalyst in a secondary cracking reactor, with dolomite and with AFRC) at temperatures of 650, 700, 750, 800 and 850 °C were carried out. Both types of catalysts have significantly affected the content of tars and other components in pyrolytic gases. The effect of catalyst on the tetrapack distribution into the product yield on the composition of gas and on the total organic carbon in the tar product is presented in this work. Copyright © 2013 Elsevier Ltd. All rights reserved.

Methane Seeps in the Gulf of Mexico: repeat acoustic surveying shows highly temporally and spatially variable venting

NASA Astrophysics Data System (ADS)

Beaumont, B. C.; Raineault, N.

2016-02-01

Scientists have recognized that natural seeps account for a large amount of methane emissions. Despite their widespread occurrence in areas like the Gulf of Mexico, little is known about the temporal variability and site-scale spatial variability of venting over time. We used repeat acoustic surveys to compare multiple days of seep activity and determine the changes in the locus of methane emission and plume height. The Sleeping Dragon site was surveyed with an EM302 multibeam sonar on three consecutive days in 2014 and 4 days within one week in 2015. The data revealed three distinctive plume regions. The locus of venting varied by 10-60 meters at each site. The plume that exhibited the least spatial variability in venting, was also the most temporally variable. This seep was present in one-third of survey dates in 2014 and three quarters of survey dates in 2015, showing high day-to-day variability. The plume height was very consistent for this plume, whereas the other plumes were more consistent temporally, but varied in maximum plume height detection by 25-85 m. The single locus of emission at the site that had high day-to-day variability may be due to a single conduit for methane release, which is sometimes closed off by carbonate or clathrate hydrate formation. In addition to day-to-day temporal variability, the locus of emission at one site was observed to shift from a point-source in 2014 to a diffuse source in 2015 at a nearby location. ROV observations showed that one of the seep sites that closed off temporarily, experienced an explosive breakthrough of gas, releasing confined methane and blowing out rock. The mechanism that causes on/off behavior of certain plumes, combined with the spatial variability of the locus of methane release shown in this study may point to carbonate or hydrate formation in the seep plumbing system and should be further investigated.

Identification of amino acids that promote specific and rigid TAR RNA-tat protein complex formation.

PubMed

Edwards, Thomas E; Robinson, Bruce H; Sigurdsson, Snorri Th

2005-03-01

The Tat protein and the transactivation responsive (TAR) RNA form an essential complex in the HIV lifecycle, and mutations in the basic region of the Tat protein alter this RNA-protein molecular recognition. Here, EPR spectroscopy was used to identify amino acids, flanking an essential arginine of the Tat protein, which contribute to specific and rigid TAR-Tat complex formation by monitoring changes in the mobility of nitroxide spin-labeled TAR RNA nucleotides upon binding. Arginine to lysine N-terminal mutations did not affect TAR RNA interfacial dynamics. In contrast, C-terminal point mutations, R56 in particular, affected the mobility of nucleotides U23 and U38, which are involved in a base-triple interaction in the complex. This report highlights the role of dynamics in specific molecular complex formation and demonstrates the ability of EPR spectroscopy to study interfacial dynamics of macromolecular complexes.

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

NASA Astrophysics Data System (ADS)

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

Machine-smoking studies of cigarette filter color to estimate tar yield by visual assessment and through the use of a colorimeter.

PubMed

Morton, Michael J; Williams, David L; Hjorth, Heather B; Smith, Jennifer H

2010-04-01

This paper explores using the intensity of the stain on the end of the filter ("filter color") as a vehicle for estimating cigarette tar yield, both by instrument reading of the filter color and by visual comparison to a template. The correlation of machine-measured tar yield to filter color measured with a colorimeter was reasonably strong and was relatively unaffected by different puff volumes or different tobacco moistures. However, the correlation of filter color to machine-measured nicotine yield was affected by the moisture content of the cigarette. Filter color, as measured by a colorimeter, was generally comparable to filter extraction of either nicotine or solanesol in its correlation to machine-smoked tar yields. It was found that the color of the tar stain changes over time. Panelists could generally correctly order the filters from machine-smoked cigarettes by tar yield using the intensity of the tar stain. However, there was considerable variation in the panelist-to-panelist tar yield estimates. The wide person-to-person variation in tar yield estimates, and other factors discussed in the text could severely limit the usefulness and practicality of this approach for visually estimating the tar yield of machine-smoked cigarettes. Copyright 2009 Elsevier Inc. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2013-05-01

, being a sediment source and an erosional mechanism. On the GB stratification, we observe a low angle unconformity given by a transparent acoustical layer. Also, the reflectors at the GB edge and adjacent to GTF structure suggest that the stratification till upward to the scarp. Nevertheless, that GTF scarp represents the eroded paleo-slope of the Sonora Margin, exposing the cutting layers on its facing north slope. The plumes observed near to the Satellite Basin correspond to gas seeps released on the north slope of the scarp of the GTF, where layers of the GB are exposed, and giving the absence of a seal layer. The observed inner plumes in the Satellite Basin probably use the disrupted layers of the facing south scarp of the GTF to release the gas bubbles. The new plume system found off-axis on the Northern Rift has not enough data to explain their origin and release process.

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

NASA Astrophysics Data System (ADS)

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

The linear relationship between cigarette tar and nicotine yields: regulatory implications for smoke constituent ratios.

PubMed

St Charles, F K; Cook, C J; Clayton, P M

2011-02-01

Cigarette smoke analyte yields are often expressed as ratios relative to tar or nicotine yields, usually to compare different products or to estimate human uptake of smoke in relation to nicotine uptake measurements. The method, however, can lead to distorted interpretations, especially in the case of ratios from ultra-low tar yield cigarettes. In brief, as tar yields decrease below the 5–6 mg per cigarette range, the tar-to-nicotine ratio (TNR) decreases rapidly in a non-linear fashion. If, however, the nicotine yield, rather than the ratio, is plotted versus the tar yield, the non-linearity disappears and a straight line is obtained, with a slight positive intercept for nicotine on the ordinate. Unlike the ratio, the slope appears to depend only on the concentration of the nicotine in the blend and does not appear to vary with smoking parameters such as puff volume, puff interval or length smoked or with cigarette design parameters such as length, circumference or the amount of filtration or filter ventilation. Therefore, such a slope is analogous to the TNR although, unlike that ratio, it is invariant. Even more simply, the concentration of the nicotine in the blend, at least for American blend-style cigarettes, provides a similar index.

Design-Based Peptidomimetic Ligand Discovery to Target HIV TAR RNA Using Comparative Analysis of Different Docking Methods.

PubMed

Fu, Junjie; Xia, Amy; Dai, Yao; Qi, Xin

2016-01-01

Discovering molecules capable of binding to HIV trans-activation responsive region (TAR) RNA thereby disrupting its interaction with Tat protein is an attractive strategy for developing novel antiviral drugs. Computational docking is considered as a useful tool for predicting binding affinity and conducting virtual screening. Although great progress in predicting protein-ligand interactions has been achieved in the past few decades, modeling RNA-ligand interactions is still largely unexplored due to the highly flexible nature of RNA. In this work, we performed molecular docking study with HIV TAR RNA using previously identified cyclic peptide L22 and its analogues with varying affinities toward HIV-1 TAR RNA. Furthermore, sarcosine scan was conducted to generate derivatives of CGP64222, a peptide-peptoid hybrid with inhibitory activity on Tat/TAR RNA interaction. Each compound was docked using CDOCKER, Surflex-Dock and FlexiDock to compare the effectiveness of each method. It was found that FlexiDock energy values correlated well with the experimental Kd values and could be used to predict the affinity of the ligands toward HIV-1 TAR RNA with a superior accuracy. Our results based on comparative analysis of different docking methods in RNA-ligand modeling will facilitate the structure-based discovery of HIV TAR RNA ligands for antiviral therapy.

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

NASA Astrophysics Data System (ADS)

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.

Ubiquitous tar balls with a California-source signature on the shorelines of Prince William Sound, Alaska

USGS Publications Warehouse

Kvenvolden, K.A.; Hostettler, F.D.; Carlson, P.R.; Rapp, J.B.; Threlkeld, C.N.; Warden, A.

1995-01-01

Although the shorelines of Prince William Sound still bear traces of the 1989 Exxon Valdez oil spill, most of the flattened tar balls that can be found today on these shorelines are not residues of Exxon Valdez oil. Instead, the carbon-isotopic and hydrocarbon-biomarker signatures of 61 tar ball samples, collected from shorelines throughout the northern and western parts of the sound, are all remarkably similar and have characteristics consistent with those of oil products that originated from the Monterey Formation source rocks of California. The carbon-isotopic compositions of the tar balls are all closely grouped (??13CPDB = -23.7 ?? 0.2???), within the range found in crude oils from those rocks, but are distinct from isotopic compositions of 28 samples of residues from the Exxon Valdez oil spill (??13CPDB = -29.4 ?? 0.1???). Likewise, values for selected biomarker ratios in the tar balls are all similar but distinct from values of residues from the 1989 oil spill. Carbon-isotopic and biomarker signatures generally relate the tar balls to oil products used in Alaska before ???1970 for construction and pavements. How these tar balls with such similar geochemical characteristics became so widely dispersed throughout the northern and western parts of the sound is not known with certainty, but the great 1964 Alaska earthquake was undoubtedly an important trigger, causing spills from ruptured storage facilities of California-sourced asphalt and fuel oil into Prince William Sound.

Microplastic and tar pollution on three Canary Islands beaches: An annual study.

PubMed

Herrera, A; Asensio, M; Martínez, I; Santana, A; Packard, T; Gómez, M

2018-04-01

Marine debris accumulation was analyzed from three exposed beaches of the Canary Islands (Lambra, Famara and Las Canteras). Large microplastics (1-5mm), mesoplastics (5-25mm) and tar pollution were assessed twice a month for a year. There was great spatial and temporal variability in the Canary Island coastal pollution. Seasonal patterns differed at each location, marine debris concentration depended mainly of local-scale wind and wave conditions. The most polluted beach was Lambra, a remote beach infrequently visited. The types of debris found were mainly preproduction resin pellets, plastic fragments and tar, evidencing that pollution was not of local origin, but it cames from the open sea. The levels of pollution were similar to those of highly industrialized and contaminated regions. This study corroborates that the Canary Islands are an area of accumulation of microplastics and tar rafted from the North Atlantic Ocean by the southward flowing Canary Current. Copyright © 2017 Elsevier Ltd. All rights reserved.

Numerical simulation of vortex pyrolysis reactors for condensable tar production from biomass

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

Miller, R.S.; Bellan, J.

1998-08-01

A numerical study is performed in order to evaluate the performance and optimal operating conditions of vortex pyrolysis reactors used for condensable tar production from biomass. A detailed mathematical model of porous biomass particle pyrolysis is coupled with a compressible Reynolds stress transport model for the turbulent reactor swirling flow. An initial evaluation of particle dimensionality effects is made through comparisons of single- (1D) and multi-dimensional particle simulations and reveals that the 1D particle model results in conservative estimates for total pyrolysis conversion times and tar collection. The observed deviations are due predominantly to geometry effects while directional effects frommore » thermal conductivity and permeability variations are relatively small. Rapid ablative particle heating rates are attributed to a mechanical fragmentation of the biomass particles that is modeled using a critical porosity for matrix breakup. Optimal thermal conditions for tar production are observed for 900 K. Effects of biomass identity, particle size distribution, and reactor geometry and scale are discussed.« less

Authigenic carbonates from active methane seeps offshore southwest Africa

NASA Astrophysics Data System (ADS)

Pierre, Catherine; Blanc-Valleron, Marie-Madeleine; Demange, Jérôme; Boudouma, Omar; Foucher, Jean-Paul; Pape, Thomas; Himmler, Tobias; Fekete, Noemi; Spiess, Volkhard

2012-12-01

The southwest African continental margin is well known for occurrences of active methane-rich fluid seeps associated with seafloor pockmarks at water depths ranging broadly from the shelf to the deep basins, as well as with high gas flares in the water column, gas hydrate accumulations, diagenetic carbonate crusts and highly diverse benthic faunal communities. During the M76/3a expedition of R/V METEOR in 2008, gravity cores recovered abundant authigenic carbonate concretions from three known pockmark sites—Hydrate Hole, Worm Hole, the Regab pockmark—and two sites newly discovered during that cruise, the so-called Deep Hole and Baboon Cluster. The carbonate concretions were commonly associated with seep-benthic macrofauna and occurred within sediments bearing shallow gas hydrates. This study presents selected results from a comprehensive analysis of the mineralogy and isotope geochemistry of diagenetic carbonates sampled at these five pockmark sites. The oxygen isotope stratigraphy obtained from three cores of 2-5 m length indicates a maximum age of about 60,000-80,000 years for these sediments. The authigenic carbonates comprise mostly magnesian calcite and aragonite, associated occasionally with dolomite. Their very low carbon isotopic compositions (-61.0 < δ13C ‰ V-PDB < -40.1) suggest anaerobic oxidation of methane (AOM) as the main process controlling carbonate precipitation. The oxygen isotopic signatures (+2.4 < δ18O ‰ V-PDB < +6.2) lie within the range in equilibrium under present-day/interglacial to glacial conditions of bottom seawater; alternatively, the most positive δ18O values might reflect the contribution of 18O-rich water from gas hydrate decomposition. The frequent occurrence of diagenetic gypsum crystals suggests that reduced sulphur (hydrogen sulphide, pyrite) from sub-seafloor sediments has been oxidized by oxygenated bottom water. The acidity released during this process can potentially induce the dissolution of carbonate, thereby

Pockmarks: self-scouring seep features?

USGS Publications Warehouse

Brothers, Laura L.; Kelley, Joseph T.; Belknap, Daniel F.; Barnhardt, Walter A.; Koons, Peter O.

2011-01-01

Pockmarks, or seafloor craters, occur worldwide in a variety of geologic settings and are often associated with fluid discharge. The mechanisms responsible for pockmark preservation, and pockmarks? relation to active methane venting are not well constrained. Simple numerical simulations run in 2-and 3-dimensions, and corroborated by flume tank experiments, indicate turbulence may play a role in pockmark maintenance, and, potentially, in pockmark excavation. Morphological analysis of the pockmarks indicates an abundance of flat-bottomed and/or elongated pockmarks. Pockmarks transition into furrows as the bay narrows and tidal flow is enhanced, providing unmistakable evidence of post-formation evolution. We hypothesize that some pockmarks formed from seafloor perturbations (e.g., gas or methane discharge), are1 maintained and gradually modified by vortical flow. This hypothesis provides a mechanism for pockmark preservation and enlargement without active fluid venting, which has implications for the interpretation of seafloor seep features in gas hydrates areas.

DeepMirTar: a deep-learning approach for predicting human miRNA targets.

PubMed

Wen, Ming; Cong, Peisheng; Zhang, Zhimin; Lu, Hongmei; Li, Tonghua

2018-06-01

MicroRNAs (miRNAs) are small noncoding RNAs that function in RNA silencing and post-transcriptional regulation of gene expression by targeting messenger RNAs (mRNAs). Because the underlying mechanisms associated with miRNA binding to mRNA are not fully understood, a major challenge of miRNA studies involves the identification of miRNA-target sites on mRNA. In silico prediction of miRNA-target sites can expedite costly and time-consuming experimental work by providing the most promising miRNA-target-site candidates. In this study, we reported the design and implementation of DeepMirTar, a deep-learning-based approach for accurately predicting human miRNA targets at the site level. The predicted miRNA-target sites are those having canonical or non-canonical seed, and features, including high-level expert-designed, low-level expert-designed, and raw-data-level, were used to represent the miRNA-target site. Comparison with other state-of-the-art machine-learning methods and existing miRNA-target-prediction tools indicated that DeepMirTar improved overall predictive performance. DeepMirTar is freely available at https://github.com/Bjoux2/DeepMirTar_SdA. lith@tongji.edu.cn, hongmeilu@csu.edu.cn. Supplementary data are available at Bioinformatics online.

Upgrading producer gas quality from rubber wood gasification in a radio frequency tar thermocatalytic treatment reactor.

PubMed

Anis, Samsudin; Zainal, Z A

2013-12-01

This study focused on improving the producer gas quality using radio frequency (RF) tar thermocatalytic treatment reactor. The producer gas containing tar, particles and water was directly passed at a particular flow rate into the RF reactor at various temperatures for catalytic and thermal treatments. Thermal treatment generates higher heating value of 5.76 MJ Nm(-3) at 1200°C. Catalytic treatments using both dolomite and Y-zeolite provide high tar and particles conversion efficiencies of about 97% on average. The result also showed that light poly-aromatic hydrocarbons especially naphthalene and aromatic compounds particularly benzene and toluene were still found even at higher reaction temperatures. Low energy intensive RF tar thermocatalytic treatment was found to be effective for upgrading the producer gas quality to meet the end user requirements and increasing its energy content. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potential impacts to perennial springs from tar sand mining, processing, and disposal on the Tavaputs Plateau, Utah, USA.

PubMed

Johnson, William P; Frederick, Logan E; Millington, Mallory R; Vala, David; Reese, Barbara K; Freedman, Dina R; Stenten, Christina J; Trauscht, Jacob S; Tingey, Christopher E; Kip Solomon, D; Fernandez, Diego P; Bowen, Gabriel J

2015-11-01

Similar to fracking, the development of tar sand mining in the U.S. has moved faster than understanding of potential water quality impacts. Potential water quality impacts of tar sand mining, processing, and disposal to springs in canyons incised approximately 200 m into the Tavaputs Plateau, at the Uinta Basin southern rim, Utah, USA, were evaluated by hydrogeochemical sampling to determine potential sources of recharge, and chemical thermodynamic estimations to determine potential changes in transfer of bitumen compounds to water. Because the ridgetops in an area of the Tavaputs Plateau named PR Spring are starting to be developed for their tar sand resource, there is concern for potential hydrologic connection between these ridgetops and perennial springs in adjacent canyons on which depend ranching families, livestock, wildlife and recreationalists. Samples were collected from perennial springs to examine possible progression with elevation of parameters such as temperature, specific conductance, pH, dissolved oxygen, isotopic tracers of phase change, water-rock interaction, and age since recharge. The groundwater age dates indicate that the springs are recharged locally. The progression of hydrogeochemical parameters with elevation, in combination with the relatively short groundwater residence times, indicate that the recharge zone for these springs includes the surrounding ridges, and thereby suggests a hydrologic connection between the mining, processing, disposal area and the springs. Estimations based on chemical thermodynamic approaches indicate that bitumen compounds will have greatly enhanced solubility in water that comes into contact with the residual bitumen-solvent mixture in disposed tailings relative to water that currently comes into contact with natural tar. Copyright © 2015 Elsevier B.V. All rights reserved.

Microbial Oxidation of Natural Gas in a Plume Emanating from the Coal Oil Point Seep Field

NASA Astrophysics Data System (ADS)

Mendes, S. D.; Valentine, D. L.; Perez, C.; Scarlett, R.

2012-12-01

The hydrocarbon seep field at Coal Oil Point, off the coast of Santa Barbara, California, releases > 1010 g of thermogenic natural gas each year. Gases emitted from Coal Oil Point include methane, ethane, propane, and butane, which are atmospheric pollutants and greenhouse gases. Even though the seeps are at water depths of only 5-80 m, much of the gas dissolves and contributes to a plume that is transported by ocean currents. While hydrocarbons can support bacterial respiration, resulting in the removal of hydrocarbon gas from the plume, the time-scale for the bacterial respiratory response is unconstrained. To track hydrocarbon respiration 3H-ethane, propane, and butane were synthesized using Grignard reagents and tritiated water with yields of >70% and applied as tracers to samples up- and down-current from the seeps at Coal Oil Point. Validation experiments conducted in September 2011 aboard the R/V Atlantis show that 3H-labeled tracers are an order of magnitude more sensitive than previous methods using stable carbon isotopes (Valentine et. al 2010), making this technique preferable in natural systems. Application of the tracers concurrent with plume tracking in July-August 2012 show ethane, propane, and butane consumption are readily inducible on a timescale of days.

SULFUR TOLERANT CATALYSTS FOR BIOMASS TAR REMOVAL - PHASE I

EPA Science Inventory

In this Small Business Innovation Research (SBIR) project, NexTech Materials proposes a catalytic reforming approach to remove waste tar from gasified biomass on nickel-based catalysts. Biomass gasification is a potential renewable route to producing electricity, liquid fue...

Hydrocarbon Seeps Formations: a Study Using 3-D Seismic Attributes in Combination with Satellite Data

NASA Astrophysics Data System (ADS)

Garcia-Pineda, O. G.; MacDonald, I. R.; Shedd, W.

2011-12-01

Analyzing the magnitude of oil discharges from natural hydrocarbon seeps is important in improving our understanding of carbon contribution as oil migrates from deeper sediments to the water column, and then eventually to the atmosphere. Liquid hydrocarbon seepage in the deep water of the Gulf of Mexico (GOM) is associated with deep cutting faults, associated with vertical salt movement, that provide conduits for the upward migration of oil and gas. Seeps transform surface geology and generate prominent geophysical targets that can be identified on 3-D seismic data as seafloor amplitude anomalies maps that correlate with the underlying deep fault systems. Using 3D seismic data, detailed mapping of the northern GOM has identified more than 21,000 geophysical anomalies across the basin. In addition to seismic data, Synthetic Aperture Radar (SAR) images have proven to be a reliable tool for localizing natural seepage of oil. We used a Texture Classifier Neural Network Algorithm (TCNNA) to process more than 1200 SAR images collected over the GOM. We quantified more than 900 individual seep formations distributed along the continental shelf and in deep water. Comparison of the geophysical anomalies with the SAR oil slick targets shows good general agreement between the distributions of the two indicators. However, there are far fewer active oil slicks than geophysical anomalies, most of which are probably associated with gas seepage. By examining several sites where the location of active venting can be determined by submersibles observations, we found that the active oily vents are often spatially offset from the most intense geophysical targets (i.e. GC600, GC767, GC204, etc). In addition to the displacement of the oil by deep sea currents, we propose that during the 100K years of activity, the location of the vents on the seafloor probably migrate as carbonate cementation reduces the permeability of the upper sediment. Many of the geophysical targets may represent

Laboratory studies to characterize the efficacy of sand capping a coal tar-contaminated sediment.

PubMed

Hyun, Seunghun; Jafvert, Chad T; Lee, Linda S; Rao, P Suresh C

2006-06-01

Placement of a microbial active sand cap on a coal tar-contaminated river sediment has been suggested as a cost effective remediation strategy. This approach assumes that the flux of contaminants from the sediment is sufficiently balanced by oxygen and nutrient fluxes into the sand layer such that microbial activity will reduce contaminant concentrations within the new benthic zone and reduce the contaminant flux to the water column. The dynamics of such a system were evaluated using batch and column studies with microbial communities from tar-contaminated sediment under different aeration and nutrient inputs. In a 30-d batch degradation study on aqueous extracts of coal tar sediment, oxygen and nutrient concentrations were found to be key parameters controlling the degradation rates of polycyclic aromatic hydrocarbons (PAHs). For the five PAHs monitored (naphthalene, fluorene, phenanthrene, anthracene, and pyrene), degradation rates were inversely proportional to molecular size. For the column studies, where three columns were packed with a 20-cm sand layer on the top of a 5 cm of sediment layer, flow was established to sand layers with (1) aerated water, (2) N(2) sparged water, or (3) HgCl(2)-sterilized N(2) sparged water. After steady-state conditions, PAH concentrations in effluents were the lowest in the aerated column, except for pyrene, whose concentration was invariant with all effluents. These laboratory scale studies support that if sufficient aeration can be achieved in the field through either active and passive means, the resulting microbially active sand layer can improve the water quality of the benthic zone and reduce the flux of many, but not all, PAHs to the water column.

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

NASA Astrophysics Data System (ADS)

Niemann, H.; Elvert, M.; Hovland, M.; Orcutt, B.; Judd, A.; Suck, I.; Gutt, J.; Joye, S.; Damm, E.; Finster, K.; Boetius, A.

2005-11-01

The North Sea hosts large coal, oil and gas reservoirs of commercial value. Natural leakage pathways of subsurface gas to the hydrosphere have been recognized during geological surveys (Hovland and Judd, 1988). 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. In this study, we report of an active seep site (56°29.90'N, 2°59.80'E) located in the Tommeliten area, Norwegian Block 1/9, at 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 during deep mixing situations. In the vicinity of the gas seeps, sea floor observations showed small mats of giant sulphide-oxidizing bacteria above patches of black sediments and 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 Sulphate-Methane Transition Zone (SMTZ). The SMTZ of Tommeliten 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 give evidence that AOM at the Tommeliten SMTZ is mediated by archaea belonging to the ANME-1b

33 CFR 165.927 - Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site, Duluth, MN.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site, Duluth, MN. 165.927 Section 165.927 Navigation and Navigable... Coast Guard District § 165.927 Safety Zone; St. Louis River, Duluth/Interlake Tar Remediation Site...

Supercritical-Fluid Extraction of Oil From Tar Sands

NASA Technical Reports Server (NTRS)

Compton, L. E.

1982-01-01

New supercritical solvent mixtures have been laboratory-tested for extraction of oil from tar sands. Mixture is circulated through sand at high pressure and at a temperature above critical point, dissolving organic matter into the compressed gas. Extract is recovered from sand residues. Low-temperature super-critical solvents reduce energy consumption and waste-disposal problems.

Impact of Genetic Variations in HIV-1 Tat on LTR-Mediated Transcription via TAR RNA Interaction.

PubMed

Ronsard, Larance; Ganguli, Nilanjana; Singh, Vivek K; Mohankumar, Kumaravel; Rai, Tripti; Sridharan, Subhashree; Pajaniradje, Sankar; Kumar, Binod; Rai, Devesh; Chaudhuri, Suhnrita; Coumar, Mohane S; Ramachandran, Vishnampettai G; Banerjea, Akhil C

2017-01-01

HIV-1 evades host defense through mutations and recombination events, generating numerous variants in an infected patient. These variants with an undiminished virulence can multiply rapidly in order to progress to AIDS. One of the targets to intervene in HIV-1 replication is the trans -activator of transcription (Tat), a major regulatory protein that transactivates the long terminal repeat promoter through its interaction with trans -activation response (TAR) RNA. In this study, HIV-1 infected patients ( n = 120) from North India revealed Ser46Phe (20%) and Ser61Arg (2%) mutations in the Tat variants with a strong interaction toward TAR leading to enhanced transactivation activities. Molecular dynamics simulation data verified that the variants with this mutation had a higher binding affinity for TAR than both the wild-type Tat and other variants that lacked Ser46Phe and Ser61Arg. Other mutations in Tat conferred varying affinities for TAR interaction leading to differential transactivation abilities. This is the first report from North India with a clinical validation of CD4 counts to demonstrate the influence of Tat genetic variations affecting the stability of Tat and its interaction with TAR. This study highlights the co-evolution pattern of Tat and predominant nucleotides for Tat activity, facilitating the identification of genetic determinants for the attenuation of viral gene expression.

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

DTIC Science & Technology

1998-04-01

This document covers the ecology of, impacts to, and management for imbedded (or " inclusional ") wetland communities within the matrix. These wetland...Figure 3. Costal Plain depression pond in Georgia. These inclusional communities usually are not treated separately in literature syntheses regarding...Associated Plant Communities Herbaceous hillside seeps, wet savannas, and small depression ponds exist as inclusional communities within more extensive

Method of producing drive fluid in situ in tar sands formations

DOEpatents

Mudunuri, Ramesh Raju; Jaiswal, Namit; Vinegar, Harold J.; Karanikas, John Michael

2010-03-23

Methods of treating a tar sands formation are described herein. Methods for treating a tar sands may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. The heat may be allowed to transfer from the heaters to at least a portion of the formation such that a drive fluid is produced in situ in the formation. The drive fluid may move at least some mobilized, visbroken, and/or pyrolyzed hydrocarbons from a first portion of the formation to a second portion of the formation. At least some of the mobilized, visbroken, and/or pyrolyzed hydrocarbons may be produced from the formation.

Methane-carbon flow into the benthic food web at cold seeps--a case study from the Costa Rica subduction zone.

PubMed

Niemann, Helge; Linke, Peter; Knittel, Katrin; MacPherson, Enrique; Boetius, Antje; Brückmann, Warner; Larvik, Gaute; Wallmann, Klaus; Schacht, Ulrike; Omoregie, Enoma; Hilton, David; Brown, Kevin; Rehder, Gregor

2013-01-01

Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as -53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other (13)C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus.

Marketing 'less harmful, low-tar' cigarettes is a key strategy of the industry to counter tobacco control in China.

PubMed

Yang, Gonghuan

2014-03-01

While the 'low-tar' scheme has been widely recognised as a misleading tactic used by the tobacco industry to deceive the public about the true risks of cigarette smoking, a similar campaign using the slogan of 'less harmful, low tar' was launched by the Chinese tobacco industry, that is, State Tobacco Monopoly Administration/China National Tobacco Corporation and began to gain traction during the last decade. Despite the fact that no sufficient research evidence supports the claims made by the industry that these cigarettes are safer, the Chinese tobacco industry has continued to promote them using various health claims. As a result, the production and sales of 'less harmful, low-tar' cigarettes have increased dramatically since 2000. Recently, a tobacco industry senior researcher, whose main research area is 'less harmful, low-tar' cigarettes, was elected as an Academician to the prestigious Chinese Academy of Engineering for his contribution to developing 'less harmful, low-tar' cigarettes. The tobacco researcher's election caused an outcry from the tobacco control community and the general public in China. This paper discusses the Chinese tobacco industry's 'less harmful, low-tar' initiatives and calls for the Chinese government to stop the execution of this deceptive strategy for tobacco marketing.

Relationship between cigarette format and mouth-level exposure to tar and nicotine in smokers of Russian king-size cigarettes.

PubMed

Ashley, Madeleine; Dixon, Mike; Prasad, Krishna

2014-10-01

Differences in length and circumference of cigarettes may influence smoker behaviour and exposure to smoke constituents. Superslim king-size (KSSS) cigarettes (17mm circumference versus 25mm circumference of conventional king-size [KS] cigarettes), have gained popularity in several countries, including Russia. Some smoke constituents are lower in machine-smoked KSSS versus KS cigarettes, but few data exist on actual exposure in smokers. We investigated mouth-level exposure (MLE) to tar and nicotine in Russian smokers of KSSS versus KS cigarettes and measured smoke constituents under machine-smoking conditions. MLE to tar was similar for smokers of 1mg ISO tar yield products, but lower for smokers of 4mg and 7mg KSSS versus KS cigarettes. MLE to nicotine was lower in smokers of 4mg KSSS versus KS cigarettes, but not for other tar bands. No gender differences were observed for nicotine or tar MLE. Under International Organization for Standardization, Health Canada Intense and Massachusetts regimes, KSSS cigarettes tended to yield less carbon monoxide, acetaldehyde, nitric oxide, acrylonitrile, benzene, 1,3-butadiene and tobacco-specific nitrosamines, but more formaldehyde, than KS cigarettes. In summary, differences in MLE were observed between cigarette formats, but not systematically across pack tar bands. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Identification and characterization of a HeLa nuclear protein that specifically binds to the trans-activation-response (TAR) element of human immunodeficiency virus.

PubMed Central

Marciniak, R A; Garcia-Blanco, M A; Sharp, P A

1990-01-01

Human immunodeficiency virus type 1 RNAs contain a sequence, trans-activation-response (TAR) element, which is required for tat protein-mediated trans-activation of viral gene expression. We have identified a nuclear protein from extracts of HeLa cells that binds to the TAR element RNA in a sequence-specific manner. The binding of this 68-kDa polypeptide was detected by UV cross-linking proteins to TAR element RNA transcribed in vitro. Competition experiments were performed by using a partially purified preparation of the protein to quantify the relative binding affinities of TAR element RNA mutants. The binding affinity of the TAR mutants paralleled the reported ability of those mutants to support tat trans-activation in vivo. We propose that this cellular protein moderates TAR activity in vivo. Images PMID:2333305

Pyrolysis characteristics and kinetics of acid tar waste from crude benzol refining: A thermogravimetry-mass spectrometry analysis.

PubMed

Chihobo, Chido H; Chowdhury, Arindrajit; Kuipa, Pardon K; Simbi, David J

2016-12-01

Pyrolysis is an attractive thermochemical conversion technology that may be utilised as a safe disposal option for acid tar waste. The kinetics of acid tar pyrolysis were investigated using thermogravimetry coupled with mass spectrometry under a nitrogen atmosphere at different heating rates of 10, 15 and 20 K min -1 The thermogravimetric analysis shows three major reaction peaks centred around 178 °C, 258 °C, and 336 °C corresponding to the successive degradation of water soluble lower molecular mass sulphonic acids, sulphonated high molecular mass hydrocarbons, and high molecular mass hydrocarbons. The kinetic parameters were evaluated using the iso-conversional Kissinger-Akahira-Sunose method. A variation in the activation energy with conversion revealed that the pyrolysis of the acid tar waste progresses through complex multi-step kinetics. Mass spectrometry results revealed a predominance of gases such as hydrogen, methane and carbon monoxide, implying that the pyrolysis of acid tar waste is potentially an energy source. Thus the pyrolysis of acid tar waste may present a viable option for its environmental treatment. There are however, some limitations imposed by the co-evolution of corrosive gaseous components for which appropriate considerations must be provided in both pyrolysis reactor design and selection of construction materials. © The Author(s) 2016.

Diversity and Functional Analysis of Bacterial Communities Associated with Natural Hydrocarbon Seeps in Acidic Soils at Rainbow Springs, Yellowstone National Park

PubMed Central

Hamamura, Natsuko; Olson, Sarah H.; Ward, David M.; Inskeep, William P.

2005-01-01

In this paper we describe the bacterial communities associated with natural hydrocarbon seeps in nonthermal soils at Rainbow Springs, Yellowstone National Park. Soil chemical analysis revealed high sulfate concentrations and low pH values (pH 2.8 to 3.8), which are characteristic of acid-sulfate geothermal activity. The hydrocarbon composition of the seep soils consisted almost entirely of saturated, acyclic alkanes (e.g., n-alkanes with chain lengths of C15 to C30, as well as branched alkanes, predominately pristane and phytane). Bacterial populations present in the seep soils were phylogenetically characterized by 16S rRNA gene clone library analysis. The majority of the sequences recovered (>75%) were related to sequences of heterotrophic acidophilic bacteria, including Acidisphaera spp. and Acidiphilium spp. of the α-Proteobacteria. Clones related to the iron- and sulfur-oxidizing chemolithotroph Acidithiobacillus spp. were also recovered from one of the seep soils. Hydrocarbon-amended soil-sand mixtures were established to examine [14C]hexadecane mineralization and corresponding changes in the bacterial populations using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Approximately 50% of the [14C]hexadecane added was recovered as 14CO2 during an 80-day incubation, and this was accompanied by detection of heterotrophic acidophile-related sequences as dominant DGGE bands. An alkane-degrading isolate was cultivated, whose 16S rRNA gene sequence was identical to the sequence of a dominant DGGE band in the soil-sand mixture, as well as the clone sequence recovered most frequently from the original soil. This and the presence of an alkB gene homolog in this isolate confirmed the alkane degradation capability of one population indigenous to acidic hydrocarbon seep soils. PMID:16204508

Diversity and functional analysis of bacterial communities associated with natural hydrocarbon seeps in acidic soils at Rainbow Springs, Yellowstone National Park.

PubMed

Hamamura, Natsuko; Olson, Sarah H; Ward, David M; Inskeep, William P

2005-10-01

In this paper we describe the bacterial communities associated with natural hydrocarbon seeps in nonthermal soils at Rainbow Springs, Yellowstone National Park. Soil chemical analysis revealed high sulfate concentrations and low pH values (pH 2.8 to 3.8), which are characteristic of acid-sulfate geothermal activity. The hydrocarbon composition of the seep soils consisted almost entirely of saturated, acyclic alkanes (e.g., n-alkanes with chain lengths of C15 to C30, as well as branched alkanes, predominately pristane and phytane). Bacterial populations present in the seep soils were phylogenetically characterized by 16S rRNA gene clone library analysis. The majority of the sequences recovered (>75%) were related to sequences of heterotrophic acidophilic bacteria, including Acidisphaera spp. and Acidiphilium spp. of the alpha-Proteobacteria. Clones related to the iron- and sulfur-oxidizing chemolithotroph Acidithiobacillus spp. were also recovered from one of the seep soils. Hydrocarbon-amended soil-sand mixtures were established to examine [14C]hexadecane mineralization and corresponding changes in the bacterial populations using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Approximately 50% of the [14C]hexadecane added was recovered as 14CO2 during an 80-day incubation, and this was accompanied by detection of heterotrophic acidophile-related sequences as dominant DGGE bands. An alkane-degrading isolate was cultivated, whose 16S rRNA gene sequence was identical to the sequence of a dominant DGGE band in the soil-sand mixture, as well as the clone sequence recovered most frequently from the original soil. This and the presence of an alkB gene homolog in this isolate confirmed the alkane degradation capability of one population indigenous to acidic hydrocarbon seep soils.

Carbon, oxygen and strontium isotopic constraints on fluid sources, temperatures and biogeochemical processes during the formation of seep carbonates - Secchia River site, Northern Apennines

NASA Astrophysics Data System (ADS)

Viola, Irene; Capozzi, Rossella; Bernasconi, Stefano M.; Rickli, Jörg

2017-07-01

Understanding authigenic seep carbonate formation provides clues for hydrocarbon exploration and insights into contributions to gas budgets of marine environments and the atmosphere. Seep carbonates discovered in the outcropping succession along the Secchia riverbanks (near Modena, Italy) belong to the Argille Azzurre Formation of Early Pleistocene age deposited in an upper shelf environment overlying the Miocene foredeep successions, which include hydrocarbon fields. The fluid migration from the hydrocarbon fields, up to the surface, is presently active on land and started in the marine succession during the Late Miocene. Authigenic globular carbonate concretions and carbonate chimneys are interspersed along the strata throughout the section. A comprehensive geochemical characterisation of the carbonates has been carried out to understand the processes leading to their formation. The carbonate concretions are the record of past hydrocarbon vents linked to the Miocene petroleum system of the Northern Apennines. The samples are composed of > 50% microcrystalline dolomite. The δ13C signatures identify two groups in the samples according to different type of formation processes. Globular concretions have positive values that suggest an influence of CO2 associated to secondary methanogenesis due to microbial degradation of higher hydrocarbons. The analysed chimney, with negative δ13C values, is interpreted as former conduit where carbonate precipitation is promoted by Anaerobic Oxidation of Methane coupled with Sulfate Reduction. The δ18O range, coupled with 87/86Sr signatures, indicate that the contribution of deep connate water from the Miocene reservoirs is up to 23% during the formation of the globular concretions. The connate water occurrence is also documented by higher ambient temperatures. The different isotope signatures in seep carbonates result from the relative contribution of the recognised gas and water components, linked to different plumbing systems

Diversity of symbioses between chemosynthetic bacteria and metazoans at the Guiness cold seep site (Gulf of Guinea, West Africa)

PubMed Central

Duperron, Sébastien; Rodrigues, Clara F; Léger, Nelly; Szafranski, Kamil; Decker, Carole; Olu, Karine; Gaudron, Sylvie M

2012-01-01

Fauna from deep-sea cold seeps worldwide is dominated by chemosymbiotic metazoans. Recently, investigation of new sites in the Gulf of Guinea yielded numerous new species for which symbiosis was strongly suspected. In this study, symbioses are characterized in five seep-specialist metazoans recently collected from the Guiness site located at ∼600 m depth. Four bivalve and one annelid species belonging to families previously documented to harbor chemosynthetic bacteria were investigated using bacterial marker gene sequencing, fluorescence in situ hybridization, and stable isotope analyses. Results support that all five species display chemosynthetic, sulfur-oxidizing γ-proteobacteria. Bacteria are abundant in the gills of bivalves, and in the trophosome of the siboglinid annelid. As observed for their relatives occurring at deeper sites, chemoautotrophy is a major source of carbon for animal nutrition. Although symbionts found in each host species are related to symbionts found in other metazoans from the same families, several incongruencies are observed among phylogenetic trees obtained from the different bacterial genes, suggesting a certain level of heterogeneity in symbiont strains present. Results provide new insights into the diversity, biogeography, and role of symbiotic bacteria in metazoans from the Gulf of Guinea, at a site located at an intermediate depth between the continental shelf and the deep sea. PMID:23233246

Evidence of active methanogen communities in shallow sediments of the sonora margin cold seeps.

PubMed

Vigneron, Adrien; L'Haridon, Stéphane; Godfroy, Anne; Roussel, Erwan G; Cragg, Barry A; Parkes, R John; Toffin, Laurent

2015-05-15

In the Sonora Margin cold seep ecosystems (Gulf of California), sediments underlying microbial mats harbor high biogenic methane concentrations, fueling various microbial communities, such as abundant lineages of anaerobic methanotrophs (ANME). However, the biodiversity, distribution, and metabolism of the microorganisms producing this methane remain poorly understood. In this study, measurements of methanogenesis using radiolabeled dimethylamine, bicarbonate, and acetate showed that biogenic methane production in these sediments was mainly dominated by methylotrophic methanogenesis, while the proportion of autotrophic methanogenesis increased with depth. Congruently, methane production and methanogenic Archaea were detected in culture enrichments amended with trimethylamine and bicarbonate. Analyses of denaturing gradient gel electrophoresis (DGGE) fingerprinting and reverse-transcribed PCR-amplified 16S rRNA sequences retrieved from these enrichments revealed the presence of active methylotrophic Methanococcoides burtonii relatives and several new autotrophic Methanogenium lineages, confirming the cooccurrence of Methanosarcinales and Methanomicrobiales methanogens with abundant ANME populations in the sediments of the Sonora Margin cold seeps. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

In situ heat treatment of a tar sands formation after drive process treatment

DOEpatents

Vinegar, Harold J.; Stanecki, John

2010-09-21

A method for treating a tar sands formation includes providing a drive fluid to a hydrocarbon containing layer of the tar sands formation to mobilize at least some hydrocarbons in the layer. At least some first hydrocarbons from the layer are produced. Heat is provided to the layer from one or more heaters located in the formation. At least some second hydrocarbons are produced from the layer of the formation. The second hydrocarbons include at least some hydrocarbons that are upgraded compared to the first hydrocarbons produced by using the drive fluid.

Functional analysis of a Wheat Homeodomain protein, TaR1, reveals that host chromatin remodelling influences the dynamics of the switch to necrotrophic growth in the phytopathogenic fungus Zymoseptoria tritici.

PubMed

Lee, Jack; Orosa, Beatriz; Millyard, Linda; Edwards, Martin; Kanyuka, Kostya; Gatehouse, Angharad; Rudd, Jason; Hammond-Kosack, Kim; Pain, Naomi; Sadanandom, Ari

2015-04-01

A distinguishing feature of Septoria leaf blotch disease in wheat is the long symptomless growth of the fungus amongst host cells followed by a rapid transition to necrotrophic growth resulting in disease lesions. Global reprogramming of host transcription marks this switch to necrotrophic growth. However no information exists on the components that bring about host transcriptional reprogramming. Gene-silencing, confocal-imaging and protein-protein interaction assays where employed to identify a plant homeodomain (PHD) protein, TaR1 in wheat that plays a critical role during the transition from symptomless to necrotrophic growth of Septoria. TaR1-silenced wheat show earlier symptom development upon Septoria infection but reduced fungal sporulation indicating that TaR1 is key for prolonging the symptomless phase and facilitating Septoria asexual reproduction. TaR1 is localized to the nucleus and binds to wheat Histone 3. Trimethylation of Histone 3 at lysine 4 (H3K4) and lysine 36 (H3K36) are found on open chromatin with actively transcribed genes, whereas methylation of H3K27 and H3K9 are associated with repressed loci. TaR1 specifically recognizes dimethylated and trimethylated H3K4 peptides suggesting that it regulates transcriptional activation at open chromatin. We conclude that TaR1 is an important component for the pathogen life cycle in wheat that promotes successful colonization by Septoria. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Cigarettes, lung cancer, and coronary heart disease: the effects of inhalation and tar yield.

PubMed

Higenbottam, T; Shipley, M J; Rose, G

1982-06-01

Ten-year mortality rates for lung cancer and coronary heart disease have been related to cigarette smoking habits in 17 475 male civil servants aged 40-64 and in sample of 8089 male British residents aged 35-69. Both diseases were more frequent in smokers. Lung cancer rates were higher overall for "non-inhalers", particularly in heavy smokers. Tar yield correlated with the risk of lung cancer in non-inhalers but less so in inhalers. Conversely, coronary deaths were more common among inhalers, and the effect of tar/nicotine yield (such as it was) was confined to inhalers. It appears that there are subtle interactions between the amount smoked, the tar/nicotine yield of the cigarette, and the style of smoking. Thus the effects of a change in cigarette characteristics are hard to predict, and they may be different for respiratory and cardiovascular disease.

Properties of gasification-derived char and its utilization for catalytic tar reforming

NASA Astrophysics Data System (ADS)

Qian, Kezhen

Char is a low-value byproduct of biomass gasification and pyrolysis with many potential applications, such as soil amendment and the synthesis of activated carbon. The overall goal of the proposed research was to develop novel methods to use char derived from gasification for high-value applications in syngas conditioning. The first objective was to investigate effects of gasification condition and feedstock on properties of char derived from fluidized bed gasification. Results show that the surface areas of most of the char were 1--10 m 2/g and increased as the equivalence ratio increased. Char moisture and fixed carbon contents decreased while ash content increased as equivalence ratio increased. The next objective was to study the properties of sorghum and red cedar char derived from downdraft gasifier. Red cedar char contained more aliphatic carbon and o-alkyl carbon than sorghum char. Char derived from downdraft gasification had higher heating values and lower ash contents than char derived from fluidized bed gasification. The gasification reactivity of red cedar char was higher than that of sorghum char. Then, red cedar char based catalysts were developed with different preparation method to reform toluene and naphthalene as model tars. The catalyst prepared with nickel nitrate was found to be better than that with nickel acetate. The nickel particle size of catalyst impregnated with nickel nitrate was smaller than that of catalyst impregnated with nickel acetate. The particle size of catalyst impregnated with nickel acetate decreased by hydrazine reduction. The catalyst impregnated with nickel nitrate had the highest toluene removal efficiency, which was 70%--100% at 600--800 °C. The presence of naphthalene in tar reduced the catalyst efficiency. The toluene conversion was 36--99% and the naphthalene conversion was 37%--93% at 700--900 °C. Finally, effects of atmosphere and pressure on catalytic reforming of lignin-derived tars over the developed catalyst

Characterization of alkanes, hopanes, and polycyclic aromatic hydrocarbons (PAHs) in tar-balls collected from the East Coast of Peninsular Malaysia.

PubMed

Chandru, Kuhan; Zakaria, Mohamad Pauzi; Anita, Sofia; Shahbazi, Azadeh; Sakari, Mahyar; Bahry, Pourya Shahpoury; Mohamed, Che Abd Rahim

2008-05-01

The East Coast of Peninsular Malaysia faces the South China Sea and is vulnerable to oil pollution because of intense petroleum production activities in the area. The South China Sea is also a favored route for supertankers carrying crude oil to the Far East. Consequently, oil spills can occur, causing pollution and contamination in the surrounding areas. Residual oil spills stranded on coastal beaches usually end up as tar-balls. Elucidating the sources of tar-balls using a molecular marker approach is essential in assessing environmental impacts and perhaps settling legal liabilities for affected parties. This study utilizes a multimodal molecular marker approach through the use of diagnostic ratios of alkanes, hopanes, and polycyclic aromatic hydrocarbons (PAHs) to determine the source, distribution and weathering of tar-balls. Hopane ratios (e.g., C29/C30, and summation C31-C35/C30 ratios) were used to identify the sources of tar-balls. The weathering effects were distinguished by using alkanes, namely the unresolved complex mixture (UCM) and low molecular weight/high molecular weight (L/H) ratios. Similarly, PAHs were also used for the determination of weathering processes undergone by the tar-balls. This multimodal molecular marker gave a very strong indication of the sources of tar-balls in this study. For example, 16 out of 17 samples originated from South East Asian Crude Oil (SEACO) with one sample from Merang, Terengganu originating from North Sea Oil (Troll). The TRME-2 sample may have come from a supertanker's ballast water discharge. The second possibility is that the tar-ball may have been transported via oceanographic currents. All 'weathered' sample characterizations were based on the presence of UCM and other ratios. The multimodal molecular marker approach applied in this study has enabled us to partially understand the transport behavior of tar-balls in the marine environment and has revealed insights into the weathering process of tar-balls.

Exploring the chemical composition of pelagic tar collected in the North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Green, H. S.; Reddy, C. M.; Valentine, D. L.; Aeppli, C.; Swarthout, B.; Sharpless, C.; Joyce, P.; Meyer, A. W.; Fuller, S. A.; Gosselin, K.

2016-12-01

Pelagic tarballs have been linked to multiple sources and their abundances follow notable historical and geographic trends. An overwhelming number of studies point to operational discharges (cargo washing) as the main source of pelagic tar. In a recent review article, Warnock et al. (2015) summarized that the abundance of tar balls has decreased over the last 30 years. The decreasing trend of tarballs has been attributed to the MARPOL 73/78 Annex I legislation, which was created from conventions held in 1973 and again in 1978 to respond to several tanker accidents and other pollution-related inputs. Two of the studies supporting the "MARPOL 73/78 effect" were based on the historical record of tarballs collected in the North Atlantic Ocean by the Sea Education Association (SEA; Woods Hole, MA). To supplement the SEA record, we performed a series of geochemical analyses on 100 of the SEA samples collected from 1988 to 2014. Bulk and gas chromatographic (GC) analyses revealed that the samples were highly variable. For example, the amount of material that could be dissolved in organic solvent but not measured by gas chromatography (referred to as the % GC amenable, a proxy on the distribution of compound classes that compose the tar) ranged from 10 to 80%, although skewed to values less than 40%. Another parameter, based on the GC data, was the perecentage of the resolved relative to the unresolved signal spanned from 0.1 to 1.8. Nine of the sampes would not dissolve in organic solvents and appear to be soot or coal. This study has an operation limitation as we choose to only examine samples > 1 cm (relative to samples smaller than 1mm). Our approach was based on the assumption that these samples were the most unlikely to be weathered and hence retain the genetic features of the initially released tar. While this study does not have the capacity to test confidently the MARPOL 73/78 effect, it does show that pelagic tars are highly variable, which in turn, have

Membrane curvature and the Tol-Pal complex determine polar localization of the chemoreceptor Tar in E. coli.

PubMed

Saaki, Terrens N V; Strahl, Henrik; Hamoen, Leendert W

2018-02-20

Chemoreceptors are localized at the cell poles of Escherichia coli and other rod-shaped bacteria. Over the years different mechanisms have been put forward to explain this polar localization; from stochastic clustering, membrane curvature driven localization, interactions with the Tol-Pal complex, to nucleoid exclusion. To evaluate these mechanisms, we monitored the cellular localization of the aspartate chemoreceptor Tar in different deletion mutants. We did not find any indication for either stochastic cluster formation or nucleoid exclusion. However, the presence of a functional Tol-Pal complex appeared to be essential to retain Tar at cell poles. Interestingly, Tar still accumulated at midcell in tol and in pal deletion mutants. In these mutants, the protein appears to gather at the base of division septa, a region characterised by strong membrane curvature. Chemoreceptors, like Tar, form trimer-of-dimers that bend the cell membrane due to a rigid tripod structure. The curvature approaches the curvature of the cell membrane generated during cell division, and localization of chemoreceptor tripods at curved membrane areas is therefore energetically favourable as it lowers membrane tension. Indeed, when we introduced mutations in Tar that abolish the rigid tripod structure, the protein was no longer able to accumulate at midcell or cell poles. These findings favour a model where chemoreceptor localization in E. coli is driven by strong membrane curvature and association with the Tol-Pal complex. Importance Bacteria have exquisite mechanisms to sense and to adapt to the environment they live in. One such mechanism involves the chemotaxis signal transduction pathway, in which chemoreceptors specifically bind certain attracting or repelling molecules and transduce the signals to the cell. In different rod-shaped bacteria, these chemoreceptors localize specifically to cell poles. Here, we examined the polar localization of the aspartate chemoreceptor Tar in E. coli

Class I cultural resource overview for oil shale and tar sands areas in Colorado, Utah and Wyoming.

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

O'Rourke, D.; Kullen, D.; Gierek, L.

2007-11-01

In August 2005, the U.S. Congress enacted the Energy Policy Act of 2005, Public Law 109-58. In Section 369 of this Act, also known as the 'Oil Shale, Tar Sands, and Other Strategic Unconventional Fuels Act of 2005', Congress declared that oil shale and tar sands (and other unconventional fuels) are strategically important domestic energy resources that should be developed to reduce the nation's growing dependence on oil from politically and economically unstable foreign sources. The Bureau of Land Management (BLM) is developing a Programmatic Environmental Impact Statement (PEIS) to evaluate alternatives for establishing commercial oil shale and tar sandsmore » leasing programs in Colorado, Wyoming, and Utah. This PEIS evaluates the potential impacts of alternatives identifying BLM-administered lands as available for application for commercial leasing of oil shale resources within the three states and of tar sands resources within Utah. The scope of the analysis of the PEIS also includes an assessment of the potential effects of future commercial leasing. This Class I cultural resources study is in support of the Draft Oil Shale and Tar Sands Resource Management Plan Amendments to Address Land Use Allocations in Colorado, Utah, and Wyoming and Programmatic Environmental Impact Statement and is an attempt to synthesize archaeological data covering the most geologically prospective lands for oil shale and tar sands in Colorado, Utah, and Wyoming. This report is based solely on geographic information system (GIS) data held by the Colorado, Utah, and Wyoming State Historic Preservation Offices (SHPOs). The GIS data include the information that the BLM has provided to the SHPOs. The primary purpose of the Class I cultural resources overview is to provide information on the affected environment for the PEIS. Furthermore, this report provides recommendations to support planning decisions and the management of cultural resources that could be impacted by future oil shale

Tar-free fuel gas production from high temperature pyrolysis of sewage sludge

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

Zhang, Leguan; Xiao, Bo; Hu, Zhiquan

2014-01-15

Highlights: • High temperature pyrolysis of sewage sludge was efficient for producing tar-free fuel gas. • Complete tar removal and volatile matter release were at elevated temperature of 1300 °C. • Sewage sludge was converted to residual solid with high ash content. • 72.60% of energy conversion efficiency for gas production in high temperature pyrolysis. • Investment and costing for tar cleaning were reduced. - Abstract: Pyrolysis of sewage sludge was studied in a free-fall reactor at 1000–1400 °C. The results showed that the volatile matter in the sludge could be completely released to gaseous product at 1300 °C. Themore » high temperature was in favor of H{sub 2} and CO in the produced gas. However, the low heating value (LHV) of the gas decreased from 15.68 MJ/N m{sup 3} to 9.10 MJ/N m{sup 3} with temperature increasing from 1000 °C to 1400 °C. The obtained residual solid was characterized by high ash content. The energy balance indicated that the most heating value in the sludge was in the gaseous product.« less

Brown carbon in tar balls from smoldering biomass combustion

Treesearch

R. K. Chakrabarty; H. Moosmuller; L.-W. A. Chen; K. Lewis; W. P. Arnott; C. Mazzoleni; M. K. Dubey; C. E. Wold; W. M. Hao; S. M. Kreidenweis

2010-01-01

We report the direct observation of laboratory production of spherical, carbonaceous particles - "tar balls" - from smoldering combustion of two commonly occurring dry mid-latitude fuels. Real-time measurements of spectrally varying absorption Angstrom coefficients (AAC) indicate that a class of light absorbing organic carbon (OC) with wavelength dependent...

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

NASA Astrophysics Data System (ADS)

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

Radiocarbon dating of extinct fauna in the Americas recovered from tar pits

NASA Astrophysics Data System (ADS)

Jull, A. J. T.; Iturralde-Vinent, M.; O'Malley, J. M.; MacPhee, R. D. E.; McDonald, H. G.; Martin, P. S.; Moody, J.; Rincón, A.

2004-08-01

We have obtained radiocarbon dates by accelerator mass spectrometry on bones of extinct large mammals from tar pits. Results on some samples of Glyptodon and Holmesina (extinct large mammals similar to armadillos) yielded ages of >25 and >21 ka, respectively. We also studied the radiocarbon ages of three different samples of bones from the extinct Cuban ground sloth, Parocnus bownii, which yielded dates ranging from 4960 ± 280 to 11 880 ± 420 yr BP. In order to remove the tar component pretreat the samples sufficiently to obtain reliable dates, we cleaned the samples by Soxhlet extraction in benzene. Resulting samples of collagenous material were often small.

Linking nitrogen management, seep chemistry, and stream water quality in two agricultural headwater watersheds

USDA-ARS?s Scientific Manuscript database

Riparian seepage zones in headwater agricultural watersheds represent important sources of nitrate-nitrogen (NO3-N) to surface waters, often connecting N-rich groundwater systems to streams. In this study, we examined how NO3-N concentrations in seep and stream water were affected by NO3-N processin...

Bubble composition of natural gas seeps discovered along the Cascadia Continental Margin

NASA Astrophysics Data System (ADS)

Baumberger, T.; Merle, S. G.; Embley, R. W.; Seabrook, S.; Raineault, N.; Lilley, M. D.; Evans, L. J.; Walker, S. L.; Lupton, J. E.

2016-12-01

Gas hydrates and gas-filled pockets present in sedimentary deposits have been recognized as large reservoirs for reduced carbon in the Earth's crust. This is particularly relevant in geological settings with high carbon input, such as continental margins. During expedition NA072 on the E/V Nautilus (operated by the Ocean Exploration Trust Inc.) in June 2016, the U.S. Cascadia Continental Margin (Washington, Oregon and northern California) was explored for gas seepage from sediments. During this expedition, over 400 bubble plumes at water depths ranging from 125 and 1640 m were newly discovered, and five of them were sampled for gas bubble composition using specially designed gas tight fluid samplers mounted on the Hercules remotely operated vehicle (ROV). These gas bubble samples were collected at four different depths, 494 m (rim of Astoria Canyon), 615 and 620 m (SW Coquille Bank), 849 m (floor of Astoria Canyon) and 1227 m (Heceta SW). At the two deeper sites, exposed hydrate was present in the same area where bubbles were seeping out from the seafloor. Other than the escaping gas bubbles, no other fluid flow was visible. However, the presence of bacterial mats point to diffuse fluid flow present in the affected area. In this study we present the results of the currently ongoing geochemical analysis of the gas bubbles released at the different sites and depths. Noble gas analysis, namely helium and neon, will give information about the source of the helium as well as about potential fractionation between helium and neon associated with gas hydrates. The characterization of these gas samples will also include total gas (CO2, H2, N2, O2, Ar, CH4 and other hydrocarbons) and stable isotope analysis (C and H). This dataset will reveal the chemical composition of the seeping bubbles as well as give information about the possible sources of the carbon contained in the seeping gas.

Controlling and assessing pressure conditions during treatment of tar sands formations

DOEpatents

Zhang, Etuan; Beer, Gary Lee

2015-11-10

A method for treating a tar sands formation includes providing heat to at least part of a hydrocarbon layer in the tar sands formation from a plurality of heaters located in the formation. Heat is allowed to transfer from the heaters to at least a portion of the formation. A pressure in the portion of the formation is controlled such that the pressure remains below a fracture pressure of the formation overburden while allowing the portion of the formation to heat to a selected average temperature of at least about 280.degree. C. and at most about 300.degree. C. The pressure in the portion of the formation is reduced to a selected pressure after the portion of the formation reaches the selected average temperature.

Ecological release and niche partitioning under stress: Lessons from dorvilleid polychaetes in sulfidic sediments at methane seeps

NASA Astrophysics Data System (ADS)

Levin, Lisa A.; Ziebis, Wiebke; Mendoza, Guillermo F.; Bertics, Victoria J.; Washington, Tracy; Gonzalez, Jennifer; Thurber, Andrew R.; Ebbe, Brigitte; Lee, Raymond W.

2013-08-01

Organisms inhabiting methane seep sediments are exposed to stress in the form of high levels of hydrogen sulfide, which result mainly from sulfate reduction coupled to anaerobic methane oxidation. Dorvilleidae (Polychaeta) have successfully invaded this ecosystem, and multiple species in divergent genetic clades co-occur at high densities. At methane seeps in the NE Pacific off California and Oregon, the genera Ophryotrocha, Parougia and Exallopus are especially well represented. To test the hypothesis that dorvilleid coexistence is facilitated by niche partitioning through sulfide tolerance and trophic patterns, we examined dorvilleid species-specific patterns of occurrence and nutrition at methane seeps off Eel R. [ER] on the Californian continental slope and at Hydrate Ridge [HR] on the Oregon continental slope, and in two habitats (clam bed and microbial mat) characterized by lower and higher hydrogen sulfide levels, respectively. Microelectrode measurements of hydrogen sulfide enabled characterization of environmental sulfide levels for species sampled in background sediment cores and in colonization trays. Dorvilleids tolerated H2S levels from 10 μM to over 2.6 mM, with the majority of species inhabiting sediments with similar environmental H2S concentrations (median 85-100 μM). Dorvilleid species richness was greater at HR than ER, but did not differ between clam bed and microbial mat habitats. Species distribution patterns reflected preferences for ER clam bed (lower sulfide levels), ER mat and HR clam bed (moderate sulfide levels), or HR mat (very high sulfide levels). Nutritional patterns, including trophic diversity and functional similarity, were examined using community stable isotope metrics based on δ15N and δ13C. Within each region, dorvilleid species exhibited multiple trophic strategies. Co-existing congeners typically exhibited distinct isotope signatures, suggesting trophic partitioning. Trophic diversity and δ15N range for whole

Smokers' sensory beliefs mediate the relation between smoking a light/low tar cigarette and perceptions of harm.

PubMed

Elton-Marshall, Tara; Fong, Geoffrey T; Yong, Hua-Hie; Borland, Ron; Xu, Steve Shaowei; Quah, Anne C K; Feng, Guoze; Jiang, Yuan

2015-11-01

The sensory belief that 'light/low tar' cigarettes are smoother can also influence the belief that 'light/low tar' cigarettes are less harmful. However, the 'light' concept is one of several factors influencing beliefs. No studies have examined the impact of the sensory belief about one's own brand of cigarettes on perceptions of harm. The current study examines whether a smoker's sensory belief that their brand is smoother is associated with the belief that their brand is less harmful and whether sensory beliefs mediate the relation between smoking a 'light/low tar' cigarette and relative perceptions of harm among smokers in China. Data are from 5209 smokers who were recruited using a stratified multistage sampling design and participated in Wave 3 of the International Tobacco Control (ITC) China Survey, a face-to-face survey of adult smokers and non-smokers in seven cities. Smokers who agreed that their brand of cigarettes was smoother were significantly more likely to say that their brand of cigarettes was less harmful (p<0.001, OR=6.86, 95% CI 5.64 to 8.33). Mediational analyses using the bootstrapping procedure indicated that both the direct effect of 'light/low tar' cigarette smokers on the belief that their cigarettes are less harmful (b=0.24, bootstrapped bias corrected 95% CI 0.13 to 0.34, p<0.001) and the indirect effect via their belief that their cigarettes are smoother were significant (b=0.32, bootstrapped bias-corrected 95% CI 0.28 to 0.37, p<0.001), suggesting that the mediation was partial. These results demonstrate the importance of implementing tobacco control policies that address the impact that cigarette design and marketing can have in capitalising on the smoker's natural associations between smoother sensations and lowered perceptions of harm. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Methane-Carbon Flow into the Benthic Food Web at Cold Seeps – A Case Study from the Costa Rica Subduction Zone

PubMed Central

Niemann, Helge; Linke, Peter; Knittel, Katrin; MacPherson, Enrique; Boetius, Antje; Brückmann, Warner; Larvik, Gaute; Wallmann, Klaus; Schacht, Ulrike; Omoregie, Enoma; Hilton, David; Brown, Kevin; Rehder, Gregor

2013-01-01

Cold seep ecosystems can support enormous biomasses of free-living and symbiotic chemoautotrophic organisms that get their energy from the oxidation of methane or sulfide. Most of this biomass derives from animals that are associated with bacterial symbionts, which are able to metabolize the chemical resources provided by the seeping fluids. Often these systems also harbor dense accumulations of non-symbiotic megafauna, which can be relevant in exporting chemosynthetically fixed carbon from seeps to the surrounding deep sea. Here we investigated the carbon sources of lithodid crabs (Paralomis sp.) feeding on thiotrophic bacterial mats at an active mud volcano at the Costa Rica subduction zone. To evaluate the dietary carbon source of the crabs, we compared the microbial community in stomach contents with surface sediments covered by microbial mats. The stomach content analyses revealed a dominance of epsilonproteobacterial 16S rRNA gene sequences related to the free-living and epibiotic sulfur oxidiser Sulfurovum sp. We also found Sulfurovum sp. as well as members of the genera Arcobacter and Sulfurimonas in mat-covered surface sediments where Epsilonproteobacteria were highly abundant constituting 10% of total cells. Furthermore, we detected substantial amounts of bacterial fatty acids such as i-C15∶0 and C17∶1ω6c with stable carbon isotope compositions as low as −53‰ in the stomach and muscle tissue. These results indicate that the white microbial mats at Mound 12 are comprised of Epsilonproteobacteria and that microbial mat-derived carbon provides an important contribution to the crab's nutrition. In addition, our lipid analyses also suggest that the crabs feed on other 13C-depleted organic matter sources, possibly symbiotic megafauna as well as on photosynthetic carbon sources such as sedimentary detritus. PMID:24116017

Can sediments at hydrocarbon seep sites represent a source for marine bioavailable iron? — A case study from the South China Sea

NASA Astrophysics Data System (ADS)

Li, N.; Feng, D.; Chen, D.

2017-12-01

Niu Li1, Dong Feng1,2, and Duofu Chen2,31CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. 2Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China. 3Hadal Science and Technology Research Center, College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China. Iron is an essential micronutrient and commonly considered to be one of the key-limiting factors for biological productivity in many ocean regions. Seafloor Fe supply should be most efficient in suboxic conditions. Recent studies shown that widely spread anoxic environments can develop in hydrocarbon seep sediment and local bottom water, owing to the occurrence of aerobic and/or anaerobic methane oxidation. Under this condition, the iron in sediment can be reduced to dissolved Fe2+ in the ocean. However, questions remain about whether the hydrocarbon seep sediment can represent a source for bioavailable iron to the ocean, and the control factor for the transformation of iron in the sediment remains largely unexplored. For a number of hydrocarbon seeps from the northern and southern South China Sea, the iron speciation, pyrite sulfur isotope, and iron isotope, as well as the major and trace elements are used to constrain the intensity of cold seep, and its impact on transformation of iron in sediment. Samples from both areas show sediment iron lost during the high methane flux conditions, owing to the suboxic conditions cause by aerobic methane oxidation. On the other hand, high sediment iron content accompanied by high sulfur content can be seen during the conditions of high methane flux without the occurrence of aerobic methane oxidation, which is possible ascribed to the anaerobic methane oxidation and the release of iron through seep activity. This study reveals the transformation of iron in the sediment is closely related to the

Characteristics of PAH tar oil contaminated soils-Black particles, resins and implications for treatment strategies.

PubMed

Trellu, Clément; Miltner, Anja; Gallo, Rosita; Huguenot, David; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A; Kästner, Matthias

2017-04-05

Tar oil contamination is a major environmental concern due to health impacts of polycyclic aromatic hydrocarbons (PAH) and the difficulty of reaching acceptable remediation end-points. Six tar oil-contaminated soils with different industrial histories were compared to investigate contamination characteristics by black particles. Here we provide a simple method tested on 6 soils to visualize and identify large amounts of black particles (BP) as either solid aggregates of resinified and weathered tar oil or various wood/coke/coal-like materials derived from the contamination history. These materials contain 2-10 times higher PAH concentrations than the average soil and were dominantly found in the sand fraction containing 42-86% of the total PAH. The PAH contamination in the different granulometric fractions was directly proportional to the respective total organic carbon content, since the PAH were associated to the carbonaceous particulate materials. Significantly lower (bio)availability of PAH associated to these carbonaceous phases is widely recognized, thus limiting the efficiency of remediation techniques. We provide a conceptual model of the limited mass transfer of PAH from resinated tar oil phases to the water phase and emphasize the options to physically separate BP based on their lower bulk density and slower settling velocity. Copyright © 2017 Elsevier B.V. All rights reserved.

Aspects of tar sands development in Nigeria

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

Adewusi, V.A.

1992-07-01

Development of Nigerian massive reserves of crude bitumen and associated heavy oil is imminent in view of the impacts that the huge importation of these materials and their products have on the nation's economy, coupled with the depleting reserves of Nigeria and highlights the appropriate production technology options and their environmental implications. The utilization potentials of these resources are also enumerated, as well as the government's role in achieving accelerated, long-term tar sands development in the country.

Remediation of Coal Tar by STAR: Self-Sustaining Propagation Across Clean Gaps

NASA Astrophysics Data System (ADS)

Gerhard, J.; Brown, J.; Torero, J. L.; Grant, G.

2016-12-01

Self-sustaining Treatment for Active Remediation (STAR) is an emerging remediation technique which utilizes a subsurface smouldering reaction to destroy non-aqueous phase liquids (NAPL) in situ. The reaction is self-sustaining in that, once ignited, the destructive smouldering front will propagate outwards using only the energy embedded in the contaminant. However, it is known that coal tar can occur as both a continuous pool as well as in distinct seams separated by clean intervals. This study evaluated the hypothesis that the smouldering reaction can cross or `jump' clean gaps by transferring enough heat through the gap to re-ignite the reaction in the contaminated region beyond. Column and 2D box experiments were performed at two scales to determine the maximum clean gap which could be jumped vertically and horizontally. Once the maximum gap had been determined, sensitivity to various in situ and engineering control parameters were explored including: coal tar layer thickness, soil permeability, moisture content, NAPL saturation, and air injection flowrate. High resolution thermocouples informed the progress of the reaction, continuous gas emissions analysis revealed when the reaction was active and dormant, and detailed excavation mapped the extent of remediation and whether gaps were successfully jumped. The work demonstrated that substantial clean gaps, approaching the limit of the laboratory scale, can be jumped by the smouldering reaction using convective heat transfer. Also observed in some cases was the mobilization of pre-heated coal tar into the clean gaps and the reaction's ability to propagate through and destroy coal tar both adjacent to and within the gaps. This work is providing new insights into the robust nature of the technology for in situ applications, and indicating how extreme the heterogeneity has to be before the reaction is interrupted and a new ignition location would be required.

Coal-Tar-Based Pavement Sealcoat and PAHs: Implications for the Environment, Human Health, and Stormwater Management

PubMed Central

2012-01-01

Coal-tar-based sealcoat products, widely used in the central and eastern U.S. on parking lots, driveways, and even playgrounds, are typically 20−35% coal-tar pitch, a known human carcinogen that contains about 200 polycyclic aromatic hydrocarbon (PAH) compounds. Research continues to identify environmental compartments—including stormwater runoff, lake sediment, soil, house dust, and most recently, air—contaminated by PAHs from coal-tar-based sealcoat and to demonstrate potential risks to biological communities and human health. In many cases, the levels of contamination associated with sealed pavement are striking relative to levels near unsealed pavement: PAH concentrations in air over pavement with freshly applied coal-tar-based sealcoat, for example, were hundreds to thousands of times higher than those in air over unsealed pavement. Even a small amount of sealcoated pavement can be the dominant source of PAHs to sediment in stormwater-retention ponds; proper disposal of such PAH-contaminated sediment can be extremely costly. Several local governments, the District of Columbia, and the State of Washington have banned use of these products, and several national and regional hardware and home-improvement retailers have voluntarily ceased selling them. PMID:22296333

Coal-tar-based pavement sealcoat and PAHs: implications for the environment, human health, and stormwater management

USGS Publications Warehouse

Mahler, Barbara J.; Van Metre, Peter C.; Crane, Judy L.; Watts, Alison W.; Scoggins, Mateo; Williams, E. Spencer

2012-01-01

Coal-tar-based sealcoat products, widely used in the central and eastern U.S. on parking lots, driveways, and even playgrounds, are typically 20-35% coal-tar pitch, a known human carcinogen that contains about 200 polycyclic aromatic hydrocarbon (PAH) compounds. Research continues to identify environmental compartments—including stormwater runoff, lake sediment, soil, house dust, and most recently, air—contaminated by PAHs from coal-tar-based sealcoat and to demonstrate potential risks to biological communities and human health. In many cases, the levels of contamination associated with sealed pavement are striking relative to levels near unsealed pavement: PAH concentrations in air over pavement with freshly applied coal-tar-based sealcoat, for example, were hundreds to thousands of times higher than those in air over unsealed pavement. Even a small amount of sealcoated pavement can be the dominant source of PAHs to sediment in stormwater-retention ponds; proper disposal of such PAH-contaminated sediment can be extremely costly. Several local governments, the District of Columbia, and the State of Washington have banned use of these products, and several national and regional hardware and home-improvement retailers have voluntarily ceased selling them.

Coal-tar-based pavement sealcoat and PAHs: implications for the environment, human health, and stormwater management.

PubMed

Mahler, Barbara J; Metre, Peter C Van; Crane, Judy L; Watts, Alison W; Scoggins, Mateo; Williams, E Spencer

2012-03-20

Coal-tar-based sealcoat products, widely used in the central and eastern U.S. on parking lots, driveways, and even playgrounds, are typically 20-35% coal-tar pitch, a known human carcinogen that contains about 200 polycyclic aromatic hydrocarbon (PAH) compounds. Research continues to identify environmental compartments-including stormwater runoff, lake sediment, soil, house dust, and most recently, air-contaminated by PAHs from coal-tar-based sealcoat and to demonstrate potential risks to biological communities and human health. In many cases, the levels of contamination associated with sealed pavement are striking relative to levels near unsealed pavement: PAH concentrations in air over pavement with freshly applied coal-tar-based sealcoat, for example, were hundreds to thousands of times higher than those in air over unsealed pavement. Even a small amount of sealcoated pavement can be the dominant source of PAHs to sediment in stormwater-retention ponds; proper disposal of such PAH-contaminated sediment can be extremely costly. Several local governments, the District of Columbia, and the State of Washington have banned use of these products, and several national and regional hardware and home-improvement retailers have voluntarily ceased selling them.

Tar Creek study, Sargent oil field, Santa Clara County, California

USGS Publications Warehouse

Wagner, David L.; Fedasko, Bill; Carnahan, J.R.; Brunetti, Ross; Magoon, Leslie B.; Lillis, Paul G.; Lorenson, T.D.; Stanley, Richard G.

2002-01-01

Field work in the Tar Creek area of Sargent oil field was performed June 26 to 28, 2000. The Santa Clara County study area is located in Sections, 30, 31, and 32, Township 11 South, Range 4 East, M.D.B&M; and in Sections 25 and 36, Township 11 South, Range 3 East, M.D.B.&M., north and south of Tar Creek, west of Highway 101. The work was a cooperative effort of the California Department of Conservation's Division of Oil, Gas, and Geothermal Resources (DOGGR), California Geological Survey (CGS), and the United States Geological Survey (USGS). The purpose of the project was to map the stratigraphy and geologic structure (David Wagner, CGS); sample oil for age dating (Les Magoon, USGS); and search for undocumented wells plus conduct a GPS survey of the area (Bill Fedasko, J.P. Carnahan, and Ross Brunetti, DOGGR)

Coal-tar pavement sealants might substantially increase children's PAH exposures

USGS Publications Warehouse

Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

2012-01-01

Dietary ingestion has been identified repeatedly as the primary route of human exposure to polycyclic aromatic hydrocarbons (PAHs), seven of which are classified as probable human carcinogens (B2 PAHs) by the U.S. EPA. Humans are exposed to PAHs through ingestion of cooked and uncooked foods, incidental ingestion of soil and dust, inhalation of ambient air, and absorption through skin. Although PAH sources are ubiquitous in the environment, one recently identified PAH source stands out: Coal-tar-based pavement sealant—a product applied to many parking lots, driveways, and even playgrounds primarily in the central, southern, and eastern U.S.—has PAH concentrations 100–1000 times greater than most other PAH sources. It was reported recently that PAH concentrations in house dust in residences adjacent to parking lots with coal-tar-based sealant were 25 times higher than in residences adjacent to unsealed asphalt parking lots.

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

NASA Astrophysics Data System (ADS)

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

Citizen science identifies the effects of nitrogen dioxide and other environmental drivers on tar spot of sycamore.

PubMed

Gosling, Laura; Ashmore, Mike; Sparks, Tim; Bell, Nigel

2016-07-01

Elevated sulphur dioxide (SO2) concentrations were the major cause of the absence of symptoms of tar spot (Rhytisma acerinum) of sycamore (Acer pseudoplatanus), in urban areas in the 1970s. The subsequent large decline in SO2 concentrations has not always been accompanied by increased tar spot symptoms, for reasons that have remained unresolved. We used a large citizen science survey, providing over 1000 records across England, to test two competing hypotheses proposed in earlier studies. We were able to demonstrate the validity of both hypotheses; tar spot symptoms were reduced where there were fewer fallen leaves as a source of inoculum, and elevated nitrogen dioxide concentrations reduced tar spot symptoms above a threshold concentration of about 20 μg m(-3). Symptom severity was also lower at sites with higher temperature and lower rainfall. Our findings demonstrate the power of citizen science to resolve competing hypotheses about the impacts of air pollution and other environmental drivers. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of cavitation on the properties of coal-tar pitch as studied by gas-liquid chromatography

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

M.I. Baikenov; T.B. Omarbekov; S.K. Amerkhanova

2008-02-15

The applicability of the cavitation-wave effect to coal-tar pitch processing is considered. The results of the GLC analysis of the test material before and after rotor-pulsation cavitation treatment are given. The organic matter of coal-tar pitch was found to degrade upon cavitation; as a result of this, the yields of light and medium fractions considerably increased. 5 refs., 2 figs., 4 tabs.

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

NASA Astrophysics Data System (ADS)

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.

Morphology of Florida escarpment chemosynthetic brine seep community sites: deep-tow, seabeam, and GLORIA surveys

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

Paull, C.K.; Spiess, F.N.; Curray, J.R.

1988-02-01

The Florida Escarpment near 26/degree/N was surveyed with Deep-Tow, Seabeam, and GLORIA in the area where chemosynthetic communities were discovered via ALVIN in the abyssal Gulf of Mexico. Seabeam bathymetry and GLORIA images indicate that the escarpment is a generally straight cliff with average slopes of about 45/degree/ from 2200 to more than 3250 m. The escarpment's face is cut by 2-km wide box canyons whose head walls are as steep as the intervening escarpment's face. The shapes of these canyons are difficult to explain with the traditional models of canyon formation. Sidescan sonar images and bottom photographs reveal thatmore » the escarpment's face is composed of a series of long, straight bedding-plain terraces which are truncated along nearly vertical orthogonal joints. Exposure of these truncated strata indicate the face of the escarpment is eroded. The contact between the basal escarpment and the flat-lying abyssal hemipelagic sediments is abrupt. Basal talus is uncommon because the abyssal floor is part of the distal Mississippi fan which is rapidly burying the escarpment. However, where talus occurs, it is in tongues of angular megabreccia of meter- and larger-sized blocks which indicate periodic catastrophic collapse. Sidescan images reveal bands of contrast in the reflective texture of the sea floor that extends 10-20 m from the base along more than 10% of the surveyed area. Photographic surveys show that these areas are associated with communities of abundant organisms. Apparently chemosynthetic communities line extensive sections of the escarpment base where reduced brines seep out into the sea floor. The morphology suggests joints and deep seeps are controlling factors in scarp retreat.« less

Photovoltaic Roofs

NASA Technical Reports Server (NTRS)

Drummond, R. W., Jr.; Shepard, N. F., Jr.

1984-01-01

Solar cells perform two functions: waterproofing roof and generating electricity. Sections through horizontal and slanting joints show overlapping modules sealed by L-section rubber strips and side-by-side modules sealed by P-section strips. Water seeping through seals of slanting joints drains along channels. Rooftop photovoltaic array used watertight south facing roof, replacing shingles, tar, and gravel. Concept reduces cost of residential solar-cell array.

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

NASA Astrophysics Data System (ADS)

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

ERIC Educational Resources Information Center

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…

Effects of varying marijuana potency on deposition of tar and delta9-THC in the lung during smoking.

PubMed

Matthias, P; Tashkin, D P; Marques-Magallanes, J A; Wilkins, J N; Simmons, M S

1997-12-01

To determine whether smoking more, compared to less, potent marijuana (MJ) cigarettes to a desired level of intoxication ("high") reduces pulmonary exposure to noxious smoke components, in 10 habitual smokers of MJ, we measured respiratory delivery and deposition of tar and delta9-tetrahydrocannabinol (THC), carboxyhemoglobin (COHb) boost, smoking topography, including cumulative puff volume (CPV) and breathholding time, change in heart rate (deltaHR) and "high" during ad lib smoking of 0, 1.77, and 3.95% MJ cigarettes on 3 separate days. At each session, subjects had access to only a single MJ cigarette. On average, smoking topography and COHb boost did not differ across the different strengths of MJ, while THC delivery, as well as HR, were significantly greater (p < 0.01) and tar deposition significantly less (p < 0.03) for 3.95% than 1.77% MJ. Although individual adaptations in smoking topography for 3.95% compared to 1.77% MJ were highly variable, three subjects with the lowest 3.95% MJ:1.77% MJ ratios for CPV also displayed the lowest 3.95% MJ:1.77% MJ ratios for tar deposition. In vitro studies using a standardized smoking technique revealed a mean 25% lower tar yield from 3.95% than 1.77% MJ (p < 0.05), but no difference between 1.77% and 0% marijuana. Under the conditions of this study, we conclude that tar delivery is reduced relative to THC content in a minority of subjects, and this reduction appears to be due to a reduced intake of smoke (decreased CPV) and/or a reduced tar yield from the stronger MJ preparation.

Molecular phylogenetic and chemical analyses of the microbial mats in deep-sea cold seep sediments at the northeastern Japan Sea.

PubMed

Arakawa, Shizuka; Sato, Takako; Sato, Rumi; Zhang, Jing; Gamo, Toshitaka; Tsunogai, Urumu; Hirota, Akinari; Yoshida, Yasuhiko; Usami, Ron; Inagaki, Fumio; Kato, Chiaki

2006-08-01

Microbial communities inhabiting deep-sea cold seep sediments at the northeastern Japan Sea were characterized by molecular phylogenetic and chemical analyses. White patchy microbial mats were observed along the fault offshore the Hokkaido Island and sediment samples were collected from two stations at the southern foot of the Shiribeshi seamount (M1 site at a depth of 2,961 m on the active fault) and off the Motta Cape site (M2 site at a depth of 3,064 m off the active fault). The phylogenetic and terminal-restriction fragment polymorphism analyses of PCR-amplified 16S rRNA genes revealed that microbial community structures were different between two sampling stations. The members of ANME-2 archaea and diverse bacterial components including sulfate reducers within Deltaproteobacteria were detected from M1 site, indicating the occurrence of biologically mediated anaerobic oxidation of methane, while microbial community at M2 site was predominantly composed of members of Marine Crenarchaeota group I, sulfate reducers of Deltaproteobacteria, and sulfur oxidizers of Epsilonproteobacteria. Chemical analyses of seawater above microbial mats suggested that concentrations of sulfate and methane at M1 site were largely decreased relative to those at M2 site and carbon isotopic composition of methane at M1 site shifted heavier ((13)C-enriched), the results of which are consistent with molecular analyses. These results suggest that the mat microbial communities in deep-sea cold seep sediments at the northeastern Japan Sea are significantly responsible for sulfur and carbon circulations and the geological activity associated with plate movements serves unique microbial habitats in deep-sea environments.

Tanque Loma, a new late-Pleistocene megafaunal tar seep locality from southwest Ecuador

NASA Astrophysics Data System (ADS)

Lindsey, Emily L.; Lopez R., Eric X.

2015-01-01

, geologic context, and sedimentology of Tanque Loma suggest that this site represents a bone bed assemblage in a heavily vegetated, low-energy riparian environment with secondary infiltration of asphalt that helped to preserve the bones. The predominance of Eremotherium fossils at this site indicate that it may have been an area where these animals congregated, suggesting possible gregarious behavior in this taxon. The radiocarbon dates so far obtained on extinct taxa at Tanque Loma are consistent with a model positing earlier extinctions of megafauna in tropical South America than of related taxa further south on the continent, although this pattern may be an artifact of low sampling in the region. xml:lang="es" Aunque más de 1.000 huesos de megafauna han sido identificados en los estratos del Pleistoceno en Tanque Loma, más del 85% de esos mismos pertenecen a una sola especie, el perezoso gigante Eremotherium laurillardi. Sin embargo, otros cinco taxones de megafauna han sido recuperados de este sitio, los cuales son: Glossotherium cf. G. tropicorum, Holmesina occidentalis, cf. Notiomastodon platensis, Equus (Amerhippus) c.f. santaelenae y un cérvido identificado tentativamente en base a tamaño y geografía como cf. Odocoileus salinae. Ningún carnívoro ha sido identificado aún en Tanque Loma, y los restos de microvertebrados son muy raros en los estratos del Pleistoceno, aunque las conchas de caracol terrestre y los restos fragmentados de invertebrados marinos son encontrados ocasionalmente dentro de esas capas. Los fechados de radiocarbono por espectrómetro de acelerador de masas (AMS) en huesos de Eremotherium y cf. Notiomastodon de la capa de asfalto y por encima de esta resultaron en ˜17,000-23,500 años radiocarbónicos AP. En conjunto, la tafonomía, la composición taxonómica, el contexto geológico, y la sedimentolgía del sitio Tanque Loma surgieren que esta localidad representa un yacimiento depositado en un ambiente ribereño con bajo flujo y vegetaci

Uptake of pyrene in a breast-fed child of a mother treated with coal tar.

PubMed

Scheepers, Paul T J; van Houtum, Jeanette L M; Anzion, Rob B M; Harder, Rianne; Bos, Rob P; van der Valk, Pieter G M

2009-01-01

A woman was treated for atopic dermatitis with coal tar containing ointments. Coal tar containing ointments contain genotoxic polycyclic aromatic hydrocarbons. Over a period of 50 days the accumulated dose of different coal tar containing ointments treatments corresponded to 993 mg of pyrene and 464 mg of benz[a]pyrene. During this treatment she gave breast milk to her 3-month-old daughter. Analysis of urine samples from the breast-fed child showed elevated levels of urinary excretion of a metabolite of pyrene (1-hydroxypyrene, 1-OHP). These levels were in the same range as urinary excretion levels of this metabolite observed in the mother's urine. As no pyrene was observed in breast milk at a limit of determination of 0.0035 micromol/L, transfer of pyrene from mother to child via breast milk is not likely. Also, a low level of 1-hydroxypyrene observed in the mother's milk did not account for the observed urinary excretion levels in the child. It must therefore be assumed that pyrene was transferred from mother to child via another route, presumably direct skin-to-skin or skin-to-mouth contact. Dermatologists should inform their patients who receive treatment with coal tar containing ointments of the risk of transfer of polycyclic aromatic hydrocarbons by skin-to-skin or skin-to-mouth contact.

Tar removal during the fluidized bed gasification of plastic waste.

PubMed

Arena, Umberto; Zaccariello, Lucio; Mastellone, Maria Laura

2009-02-01

A recycled polyethylene was fed in a pilot plant bubbling fluidized bed gasifier, having an internal diameter of 0.381 m and a maximum feeding capacity of 90 kg/h. The experimental runs were carried out under various operating conditions: the bed temperature was kept at about 850 degrees C, the equivalence ratio varied between 0.2 and 0.35, the amount of bed material was between 131 and 215 kg, the fluidizing velocity was between 0.5 and 0.7 m/s, quartz sand and olivine were used as bed material, and air and steam were used as fluidizing reactants. The results confirm that the tar removal treatments applied inside the gasifier (primary methods) can eliminate or strongly reduce the need for a further downstream cleanup of the syngas. In particular, the utilization of a natural olivine as an in situ tar reduction agent remarkably improves the quality of the product gas, in terms of both high hydrogen volumetric fraction and larger syngas yield.

PeaTAR1B: Characterization of a Second Type 1 Tyramine Receptor of the American Cockroach, Periplaneta americana

PubMed Central

Balfanz, Sabine

2017-01-01

The catecholamines norepinephrine and epinephrine regulate important physiological functions in vertebrates. In insects; these neuroactive substances are functionally replaced by the phenolamines octopamine and tyramine. Phenolamines activate specific guanine nucleotide-binding (G) protein-coupled receptors (GPCRs). Type 1 tyramine receptors are better activated by tyramine than by octopamine. In contrast; type 2 tyramine receptors are almost exclusively activated by tyramine. Functionally; activation of type 1 tyramine receptors leads to a decrease in the intracellular concentration of cAMP ([cAMP]i) whereas type 2 tyramine receptors can mediate Ca2+ signals or both Ca2+ signals and effects on [cAMP]i. Here; we report that the American cockroach (Periplaneta americana) expresses a second type 1 tyramine receptor (PeaTAR1B) in addition to PeaTAR1A (previously called PeaTYR1). When heterologously expressed in flpTM cells; activation of PeaTAR1B by tyramine leads to a concentration-dependent decrease in [cAMP]i. Its activity can be blocked by a series of established antagonists. The functional characterization of two type 1 tyramine receptors from P. americana; PeaTAR1A and PeaTAR1B; which respond to tyramine by changing cAMP levels; is a major step towards understanding the actions of tyramine in cockroach physiology and behavior; particularly in comparison to the effects of octopamine. PMID:29084141

PeaTAR1B: Characterization of a Second Type 1 Tyramine Receptor of the American Cockroach, Periplaneta americana.

PubMed

Blenau, Wolfgang; Balfanz, Sabine; Baumann, Arnd

2017-10-30

The catecholamines norepinephrine and epinephrine regulate important physiological functions in vertebrates. In insects; these neuroactive substances are functionally replaced by the phenolamines octopamine and tyramine. Phenolamines activate specific guanine nucleotide-binding (G) protein-coupled receptors (GPCRs). Type 1 tyramine receptors are better activated by tyramine than by octopamine. In contrast; type 2 tyramine receptors are almost exclusively activated by tyramine. Functionally; activation of type 1 tyramine receptors leads to a decrease in the intracellular concentration of cAMP ([cAMP] i ) whereas type 2 tyramine receptors can mediate Ca 2+ signals or both Ca 2+ signals and effects on [cAMP] i . Here; we report that the American cockroach ( Periplaneta americana ) expresses a second type 1 tyramine receptor (PeaTAR1B) in addition to PeaTAR1A (previously called PeaTYR1). When heterologously expressed in flpTM cells; activation of PeaTAR1B by tyramine leads to a concentration-dependent decrease in [cAMP] i . Its activity can be blocked by a series of established antagonists. The functional characterization of two type 1 tyramine receptors from P. americana ; PeaTAR1A and PeaTAR1B; which respond to tyramine by changing cAMP levels; is a major step towards understanding the actions of tyramine in cockroach physiology and behavior; particularly in comparison to the effects of octopamine.

Cavities in trees around spring seeps in the maple-beech-birch forest type

Treesearch

Andrew B. Carey; William M. Healy

1981-01-01

We examined 913 trees of 15 species in the vicinity of eight spring seeps in a second-growth maple-beech-birch forest. We found that 18 percent of the trees had large dead limbs that indicated top rot. We found 37 cavities in 27 trees (3.0 percent). However, only seven cavities were being used by wildlife in September and mice (Peromyscus sp.) used...

Aviation Turbine Fuels from Tar Sands Bitumen and Heavy Oils. Part 2. Laboratory Sample Production.

DTIC Science & Technology

1987-07-01

tar sand bitumen from West Central Kentucky; and Sunnyside tar sand bitumen from the Uinta Basin , Utah. Each of the feedstocks had unique...fuel and about 50 volume percent heavy gas oil (600-1000°F). The Westken bitumen was overall the heaviest of the four feedstocks evaluated. K factors...was 40 weight percent and about 20 weight percent in the total crude. 3. San Ardo Heavy oil The San Ardo field is located in the Coastal basin of the

Using Stable Isotope Compositions of Animal Tissues to Infer Trophic Interactions in Gulf of Mexico Lower Slope Seep Communities

PubMed Central

Becker, Erin L.; Cordes, Erik E.; Macko, Stephen A.; Lee, Raymond W.; Fisher, Charles R.

2013-01-01

We analyzed the tissue carbon, nitrogen, and sulfur stable isotope contents of macrofaunal communities associated with vestimentiferan tubeworms and bathymodiolin mussels from the Gulf of Mexico lower continental slope (970-2800 m). Shrimp in the genus Alvinocaris associated with vestimentiferans from shallow (530 m) and deep (1400-2800 m) sites were used to test the hypothesis that seep animals derive a greater proportion of their nutrition from seeps (i.e. a lower proportion from the surface) at greater depths. To account for spatial variability in the inorganic source pool, we used the differences between the mean tissue δ13C and δ15N of the shrimp in each collection and the mean δ 13C and δ15N values of the vestimentiferans from the same collection, since vestimentiferans are functionally autotrophic and serve as a baseline for environmental isotopic variation. There was a significant negative relationship between this difference and depth for both δ13C and δ15N (p=0.02 and 0.007, respectively), which supports the hypothesis of higher dependence on seep nutrition with depth. The small polychaete worm Protomystides sp. was hypothesized to be a blood parasite of the vestimentiferan Escarpialaminata . There was a highly significant linear relationship between the δ13C values of Protomystides sp. and the E . laminata individuals to which they were attached across all collections (p < 0.001) and within a single collection (p = 0.01), although this relationship was not significant for δ15N and δ34S. We made several other qualitative inferences with respect to the feeding biology of the taxa occurring in these lower slope seeps, some of which have not been described prior to this study. PMID:24324572

Natural gas sources from methane seeps on the Northern U.S. Atlantic Margin

NASA Astrophysics Data System (ADS)

Pohlman, J.; Ruppel, C. D.; Wang, D. T.; Ono, S.; Kluesner, J.; Xu, X.; Sylva, S.; Casso, M.

2017-12-01

Following the discovery of shallow- (< 180 m) and deep-water (>1000 m) methane seeps north of Cape Hatteras on the U.S. Atlantic margin (USAM), questions have been raised about the source of the emitted gas in an area where deeply-buried thermogenic basins have been identified by the Bureau of Ocean Energy Management. In September 2015, 21 piston cores and 14 multicores were collected along a 365 km section of the margin that extends from Washington Canyon offshore of Virginia to southern New England. Several coring sites targeted gas accumulations in shallow-sediments (< 10 m below the seafloor) between water depths of 541 and 1055 m. A comprehensive compositional and isotopic analysis of gases extracted from five cores containing elevated gas concentrations is being conducted to provide a first-order characterization of natural gas sources along the USAM. Stable carbon isotope analysis of the gases is consistent with a microbial methane source at all sites with δ13C values ranging from -73.5 to -109 ‰ and C1/C2 ratios ranging from 385 to 71,000 within non-oxidizing sections of the cores. The site with the highest ethane contribution (C1/C2 = 385 to 926) is the so-called Chincoteague seep located at 1100 m water depth offshore Virginia. This seep is sourced in fractured rock imaged during a 2015 USGS multichannel seismic survey and could potentially contain a small thermogenic component. Additional isotopic data from radiocarbon, deuterium and clumped isotope analyses will further constrain the relative microbial and thermogenic contributions to the gas emissions, the age of the source rocks, and the thermal conditions under which the gas is generated. Furthermore, biogeochemical controls responsible for the exceptionally 13C-depleted δ13C values (-106.6 to -109.0 ‰) of core gas methane from the methanogenic sedimentary zone at the northern and southern sections of the continental slope will be evaluated.

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

USGS Publications Warehouse

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.

Heating tar sands formations to visbreaking temperatures

DOEpatents

Karanikas, John Michael [Houston, TX; Colmenares, Tulio Rafael [Houston, TX; Zhang, Etuan [Houston, TX; Marino, Marian [Houston, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX; Ryan, Robert Charles [Houston, TX; Beer, Gary Lee [Houston, TX; Dombrowski, Robert James [Houston, TX; Jaiswal, Namit [Houston, TX

2009-12-22

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. The heat may be controlled so that at least a majority of the section reaches an average temperature of between 200.degree. C. and 240.degree. C., which results in visbreaking of at least some hydrocarbons in the section. At least some visbroken hydrocarbon fluids may be produced from the formation.

Colonization of plant substrates at hydrothermal vents and cold seeps in the northeast Atlantic and Mediterranean and occurrence of symbiont-related bacteria

PubMed Central

Szafranski, Kamil M.; Deschamps, Philippe; Cunha, Marina R.; Gaudron, Sylvie M.; Duperron, Sébastien

2015-01-01

Reducing conditions with elevated sulfide and methane concentrations in ecosystems such as hydrothermal vents, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardized approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based sites in four distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as Epsilonproteobacteria associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at vents and seeps. PMID:25774156

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

Niemann, H.; Elvert, M.; Hovland, M.; Orcutt, B.; Judd, A.; Suck, I.; Gutt, J.; Joye, S.; Damm, E.; Finster, K.; Boetius, A.

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 rates (3 nmol cm-3 d

SURVEY OF LOW FLOW DRAINAGES AND SEEPS IN COLORADO TO ASSESS IMPLEMENTABILITY OF PASSIVE TREATMENT OPTIONS

EPA Science Inventory

Low flow drainages and seeps are typically not evaluated for mitigation due to the perceived low impact on the watershed. However, localized metals concentrations and acidity can be at levels of concern. Future passage of a “Good Samaritan Act” should increase activity at curren...

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

USGS Publications Warehouse

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

Investigating Microbial Activity in Diazotrophic Methane Seep Sediment via Transcript Analysis and Single-Cell FISH-NanoSIMS

NASA Astrophysics Data System (ADS)

Dekas, A. E.; Connon, S. A.; Chadwick, G.; Orphan, V. J.

2012-12-01

Methane seep microbial ecosystems are phylogenetically diverse and physiologically complex, and require culture-independent techniques to accurately investigate metabolic activity. In the present study we combine an RNA analysis of four key microbial genes with FISH-NanoSIMS analysis of single cells to determine the diversity of nitrogen fixing microorganisms (diazotrophs) present at a deep-sea methane-seeping site, as well as investigate the methane-dependency of a variety of community members. Recently, methane-dependent nitrogen fixation was observed in Mound 12 Costa Rica sediments, and was spatially correlated with the abundance of aggregates of anaerobic methanotrophic archaea (ANME) and sulfate reducing bacterial symbionts (SRB). Combined with the detection of 15N uptake from 15N2 in these aggregates, this suggested that the ANME-SRB aggregates are the primary diazotrophs in seep sediment. However, the diversity of dinitrogenase reductase (nifH) sequences recovered from several deep-sea locales, including Mound 12, suggests a greater diversity of diazotrophs in marine sediment. To investigate the activity of these potential diazotrophs in Mound 12 sediment, we investigated a suite of RNA transcripts in 15N2 incubations in both the presence and absence of methane: nifH, bacterial 16S rRNA, methyl coenzyme M reductase A (mcrA), and adenosine-5'-phosposulfate reductase alpha subunit (aprA). No nifH transcripts were recovered in incubations without methane, consistent with previous measurements lacking 15N2 uptake in the same sediments. The activity of the bacterial community in general, assessed by variable transcription, was also greatly affected by the presence or absence of methane. Single-cell fluorescence in situ hybridization coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS) was employed to confirm diazotrophic activity (15N2 uptake) and protein synthesis (15NH4+ uptake) of particular species implicated as ecologically important by the

Comparative carcinogenic potencies of particulates from diesel engine exhausts, coke oven emissions, roofing tar aerosols and cigarette smoke.

PubMed Central

Albert, R E

1983-01-01

Mammalian cell mutagenesis, transformation and skin tumorigenesis assays show similar results in comparing the potencies of diesel, coke oven, roofing tar and cigarette smoke particulates. These assay results are reasonably consistent with the comparative carcinogenic potencies of coke oven and roofing tar emissions as determined by epidemiological studies. The bacterial mutagenesis assay tends to show disproportionately high potencies, particularly with diesel particulates. Results to date encourage the approach to the assessment for carcinogenic risks from diesel emissions based on the use of epidemiological data on cancer induced by coke oven emissions, roofing tar particulates and cigarette smoke with the comparative potencies of these materials determined by in vivo and in vitro bioassays. PMID:6186481

Environmental controls on sulfur isotopic composition of sulfide minerals in seep carbonates from the South China Sea

NASA Astrophysics Data System (ADS)

Gong, S.; Li, N.; Liang, Q.; Chen, D.; Feng, D.

2017-12-01

Authigenic carbonates and pyrite associated with sulfate-driven anaerobic oxidation of methane (AOM) at methane seeps provide archives to explore the biogeochemical processes involved and seepage dynamics over time. The wide range and extremely high δ34Spy value of authigenic sulfide has been used to trace the AOM-related processes. However, the detail mechanism for this is unknown. We proposed the δ34Spy characteristics result from high sulfate reduction rate and its competition with sulfate supply rate. To test this hypothesis, we investigated Mo content, Sr/Ca and Mg/Ca ratios, pyrite content, and its sulfur isotopic compositions in methane-derived carbonates from Site F and Haima in northern South China Sea. Calcite and aragonite were distinguished through the Sr/Ca and Mg/Ca ratios. The data show that aragonites are always associated with relatively low δ34Spy values compared to calcites. The Mo content and pyrite have good linear correlations in both aragonites and calcites, and aragonites have more positive slope than calcites. This indicates that there is more Mo available from seawater during the aragonite precipitation. The data suggest that the low δ34Spy values are formed at higher supply rate of sulfate under relatively open system, and high δ34Spy values result from a deep sulfate methane transition zone where dissolve sulfate near to complete exhausted via AOM. The combination of a detailed elemental study of authigenic carbonate with sulfur isotopes of sulfide minerals in carbonates are promising tools for reconstructing the dynamics of seep intensities in modern and, potentially, geological record.

Natural attenuation of aged tar-oil in soils: A case study from a former gas production site

NASA Astrophysics Data System (ADS)

Ivanov, Pavel; Eickhorst, Thilo; Wehrer, Markus; Georgiadis, Anna; Rennert, Thilo; Eusterhues, Karin; Totsche, Kai Uwe

2017-04-01

unidentified, suggesting the presence of other microorganisms using high-molecular weight HC as carbon source. All contaminated layers were found to be enriched in total Fe and both dithionite-extractable and oxalate-extractable Fe. Besides, siderite crystals were identified using FTIR microscopy. The presence of secondary crystalline and poorly crystalline Fe(III)-oxides and secondary Fe(II)-carbonates in the same horizons suggests simultaneous occurrence of oxic and anoxic zones within the porous system of the contaminated layers. Although HC pollution is often considered to inhibit microbial activity in soil, in our study the layers with highest TPH-amounts were the most "alive". We assume that aging processes (the sum of volatilization, dissolution, microbial degradation, chemical oxidation, polymerization and migration) and eventually a long-term microbial adaption to the HC carbon source resulted in the development of a microbial consortium, capable of transforming high-molecular weight HC. Presumably, iron-compounds in the tar oil act as an electron acceptor and trigger HC degradation. However, to unravel natural attenuation processes and degradation pathways it seems mandatory to take into account the soil structure and spatial distribution of microbes.

Geochemical analysis of potash mine seep oils, collapsed breccia pipe oil shows and selected crude oils, Eddy County, New Mexico

USGS Publications Warehouse

Palacas, J.G.; Snyder, R.P.; Baysinger, J.P.; Threlkeld, C.N.

1982-01-01

Oil shows, in the form of oil stains and bleeding oil, in core samples from two breccia pipes, Hills A and C, Eddy County, New Mexico, and seepage oils in a potash mine near Hill C breccia pipe are geochemically similar. The geochemical similarities strongly suggest that they belong to the same family of oils and were derived from similar sources. The oils are relatively high in sulfur (0.89 to 1.23 percent), rich in hydrocarbons (average 82 percent), relatively high in saturated hydrocarbon/aromatic hydrocarbon ratios (average 2.9), and based on analysis of seep oils alone, have a low API gravity (average 19.4?). The oils are for the most part severely biodegraded as attested by the loss of n-paraffin molecules. Geochemical comparison of seven crude oils collected in the vicinity of the breccia pipes indicates that the Yates oils are the likely source of the above family of oils. Six barrels of crude oil that were dumped into a potash exploration borehole near Hill C breccia pipe, to release stuck casing, are considered an unlikely source of the breccia pipe and mine seep oils. Volumetric and hydrodynamic constraints make it highly improbable that such a small volume of 'dumped' oil could migrate over distances ranging from about 600 feet to 2.5 miles to the sites of the oil shows.

Passive acoustic records of two vigorous bubble-plume methane seeps on the Oregon continental margin

NASA Astrophysics Data System (ADS)

Dziak, R. P.; Matsumoto, H.; Merle, S. G.; Embley, R. W.; Baumberger, T.; Hammond, S. R.

2016-12-01

We present preliminary analysis of the acoustic records of two bubble-plume methane seeps recorded by an autonomous hydrophone deployed during the E/V Nautilus expedition (NA072) in June 2016. The goal of the NA072 expedition was to use the Simrad 302 as a survey tool to map bubble plumes at a regional scale along the Oregon and northern California margins, followed by in situ investigation of bubble-plume sites using the ROV Hercules. The exploration carried out during NA072 resulted in the discovery of hundreds of new individual methane seep sites in water depths ranging from 125 to 1725 m depth. A Greenridge Acousonde 3B™ hydrophone was deployed via ROV within two vigorous bubble-plume sites. Despite persistent ship and ROV propeller noise, the acoustic signature of the bubble-plume can be seen in the hydrophone record as a broadband (0.5 - 4.5 kHz) series of short duration ( 0.2-0.5 msec) pulses that occur in clusters of dozens of pulses lasting 2-3 secs. Previous studies of the passive acoustics of seep bubble-plumes indicate sound is generated during bubble formation, where detachment of the gas bubble from the end of a tube or conduit causes the bubble to oscillate, producing sound. The peak frequency f (the zeroth oscillatory mode) and the bubble equivalent spherical radius r for a given pressure P are: f = (2πr)-1 [(3γP/ρ)]1/2 where γ is the ratio of gas specific heat at constant pressure to constant volume and ρ is the water density (Leifer and Tang, 2006). Thus the frequency of a bubble's oscillation is proportional to the bubble's volume, and therefore it may be possible to use our acoustic data to obtain an estimate of the volume of methane being released at these seafloor plume sites.

Natural Offshore Oil Seepage and Related Tarball Accumulation on the California Coastline - Santa Barbara Channel and the Southern Santa Maria Basin: Source Identification and Inventory

USGS Publications Warehouse

Lorenson, T.D.; Hostettler, Frances D.; Rosenbauer, Robert J.; Peters, Kenneth E.; Dougherty, Jennifer A.; Kvenvolden, Keith A.; Gutmacher, Christina E.; Wong, Florence L.; Normark, William R.

2009-01-01

Oil spillage from natural sources is very common in the waters of southern California. Active oil extraction and shipping is occurring concurrently within the region and it is of great interest to resource managers to be able to distinguish between natural seepage and anthropogenic oil spillage. The major goal of this study was to establish the geologic setting, sources, and ultimate dispersal of natural oil seeps in the offshore southern Santa Maria Basin and Santa Barbara Basins. Our surveys focused on likely areas of hydrocarbon seepage that are known to occur between Point Arguello and Ventura, California. Our approach was to 1) document the locations and geochemically fingerprint natural seep oils or tar; 2) geochemically fingerprint coastal tar residues and potential tar sources in this region, both onshore and offshore; 3) establish chemical correlations between offshore active seeps and coastal residues thus linking seep sources to oil residues; 4) measure the rate of natural seepage of individual seeps and attempt to assess regional natural oil and gas seepage rates; and 5) interpret the petroleum system history for the natural seeps. To document the location of sub-sea oil seeps, we first looked into previous studies within and near our survey area. We measured the concentration of methane gas in the water column in areas of reported seepage and found numerous gas plumes and measured high concentrations of methane in the water column. The result of this work showed that the seeps were widely distributed between Point Conception east to the vicinity of Coal Oil Point, and that they by in large occur within the 3-mile limit of California State waters. Subsequent cruises used sidescan and high resolution seismic to map the seafloor, from just south of Point Arguello, east to near Gaviota, California. The results of the methane survey guided the exploration of the area west of Point Conception east to Gaviota using a combination of seismic instruments. The

Nutritional associations among fauna at hydrocarbon seep communities in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Macavoy, S. E.; Fisher, C. R.; Carney, R. S.; Macko, S. A.

2004-05-01

The Gulf of Mexico supports dense aggregations of megafauna associated with hydrocarbon seeps on the Louisiana Slope. The visually dominant megafauna at the seeps, mussels and tubeworms, derive their nutrition from symbiotic relationships with sulfide or methane oxidizing bacteria. The structure of the tubeworm aggregations provide biogenic habitat for numerous other species of heterotrophic animals. Carbon, nitrogen and sulfur stable isotope analyses of heterotrophic fauna collected with tubeworm aggregations in the Green Canyon Lease area (GC 185) indicate that most of these species derive the bulk of their nutrition from chemoautotrophic sources. The isotope analyses also indicates that although two species may be deriving significant nutritional input from the bivalves, none of the species analyzed are feeding directly on the tubeworms. Grazing gastropods and deposit feeding sipuncluids were used to estimate the isotopic value of the free-living chemoautotrophic bacteria associated with the tubeworms (d13C -32 to -20%; d15N 0 to 7%; d34S -14 to -1 %). The use of tissue d34S analyses in conjunction with tissue d13C and d15N led to several insights into the trophic biology of the communities that would not have been evident from tissue stable C and N analyses alone.

MultiMiTar: a novel multi objective optimization based miRNA-target prediction method.

PubMed

Mitra, Ramkrishna; Bandyopadhyay, Sanghamitra

2011-01-01

Machine learning based miRNA-target prediction algorithms often fail to obtain a balanced prediction accuracy in terms of both sensitivity and specificity due to lack of the gold standard of negative examples, miRNA-targeting site context specific relevant features and efficient feature selection process. Moreover, all the sequence, structure and machine learning based algorithms are unable to distribute the true positive predictions preferentially at the top of the ranked list; hence the algorithms become unreliable to the biologists. In addition, these algorithms fail to obtain considerable combination of precision and recall for the target transcripts that are translationally repressed at protein level. In the proposed article, we introduce an efficient miRNA-target prediction system MultiMiTar, a Support Vector Machine (SVM) based classifier integrated with a multiobjective metaheuristic based feature selection technique. The robust performance of the proposed method is mainly the result of using high quality negative examples and selection of biologically relevant miRNA-targeting site context specific features. The features are selected by using a novel feature selection technique AMOSA-SVM, that integrates the multi objective optimization technique Archived Multi-Objective Simulated Annealing (AMOSA) and SVM. MultiMiTar is found to achieve much higher Matthew's correlation coefficient (MCC) of 0.583 and average class-wise accuracy (ACA) of 0.8 compared to the others target prediction methods for a completely independent test data set. The obtained MCC and ACA values of these algorithms range from -0.269 to 0.155 and 0.321 to 0.582, respectively. Moreover, it shows a more balanced result in terms of precision and sensitivity (recall) for the translationally repressed data set as compared to all the other existing methods. An important aspect is that the true positive predictions are distributed preferentially at the top of the ranked list that makes MultiMiTar

Analytical Determination of Nicotine and Tar Levels in Various Dokha and Shisha Tobacco Products.

PubMed

Mahboub, Bassam; Mohammad, Ayesha Begum; Nahlé, Ayssar; Vats, Mayank; Al Assaf, Omar; Al-Zarooni, Hamdan

2018-05-10

In the Middle East, there is no precise data and literature on tobacco-based products, such as dokha and shisha. The proposed study aims to quantify the levels of nicotine and tar in different kinds of dokha and shisha products that are sold in the local marketplace. The amount of nicotine in dokha and shisha products can be quantitatively determined using a combination of the "kissling" and "silicotungstic acid" method proposed by Robert M. Chapin. The tar residue from the smoke sample was collected on a glass wool placed before the stopcock (tap) of a separatory funnel as the smoke passes through the inlet of an electronically controlled vacuum pump. The nicotine levels in dokha and shisha samples ranged from 23.83 to 52.80 mg/g and 0.80 to 20.52 mg/g, respectively. The nicotine level varies between different tobacco products. It varies from 0.5 to 19.5 mg/g in cigarettes, from 10.3 to 23.1 mg/g in snuff tobacco, from 11 to 18 mg/g in electronic cigarettes and from 2.9 to 16.6 mg/g in chewing tobacco. The tar levels in the dokha and shisha samples ranged from 21.6 to 45.02 mg/g and 1.68 to 11.87 mg/g, respectively. Smokers are at a high risk of getting lung cancer, chronic obstructive pulmonary disease, emphysema and coronary artery disease owing to the high levels of nicotine and tar present in dokha and shisha tobacco products. These findings contradict the widespread belief among teenagers that dokha and shisha tobacco products are safer alternatives to cigarettes.

Methane fates in the benthos and water column at cold seep sites along the continental margin of Central and North America

NASA Astrophysics Data System (ADS)

Hansman, Roberta L.; Thurber, Andrew R.; Levin, Lisa A.; Aluwihare, Lihini I.

2017-02-01

The potential influence of methane seeps on carbon cycling is a key question for global assessments, but the study of carbon cycling in surface sediments and the water column of cold seep environments is complicated by the high temporal and spatial variability of fluid and gas fluxes at these sites. In this study we directly examined carbon sources supporting benthic and planktonic food webs at venting methane seeps using isotopic and molecular approaches that integrate this variability. At four seep environments located along North and Central America, microorganisms from two size fractions were collected over several days from 2800 to 9050 l of seawater to provide a time-integrated measure of key microbial groups and the carbon sources supporting the overall planktonic microbial community. In addition to water column measurements, the extent of seafloor methane release was estimated at two of the sites by examining the stable carbon isotopic signature (δ13C) of benthic metazoan infauna. This signature reveals carbon sources fueling the base of the food chain and thus provides a metric that represents a time-integrated view of the dominant microbial processes within the sediment. The stable carbon isotopic composition of microbial DNA (δ13C-DNA), which had values between -17.0 and -19.5‰, indicated that bulk planktonic microbial production was not ultimately linked to methane or other 13C-depleted seep-derived carbon sources. Instead these data support the importance of organic carbon derived from either photo- or chemoautotrophic CO2 fixation to the planktonic food web. Results of qPCR of microbial DNA sequences coding for a subunit of the particulate methane monooxygenase gene (pmoA) showed that only a small percentage of the planktonic microbial community were potential methane oxidizers possessing pmoA (<5% of 16S rRNA gene copies). There was an overall decrease of 13C-depleted carbon fueling the benthic metazoan community from 3 to 5 cm below the seafloor

Probing Na+ Induced Changes in the HIV-1 TAR Conformational Dynamics using NMR Residual Dipolar Couplings: New Insights into the Role of Counterions and Electrostatic Interactions in Adaptive Recognition†

PubMed Central

Casiano-Negroni, Anette; Sun, Xiaoyan; Al-Hashimi, Hashim M.

2012-01-01

Many regulatory RNAs undergo large changes in structure upon recognition of proteins and ligands but the mechanism by which this occur remains poorly understood. Using NMR residual dipolar coupling (RDCs), we characterized Na+ induced changes in the structure and dynamics of the bulge-containing HIV-1 transactivation response element (TAR) RNA that mirror changes induced by small molecules bearing a different number of cationic groups. Increasing the Na+ concentration from 25 mM to 320 mM led to a continuous reduction in the average inter-helical bend angle (from 46° to 22°), inter-helical twist angle (from 66° to −18°) and inter-helix flexibility (as measured by an increase in the internal generalized degree of order from 0.56 to 0.74). Similar conformational changes were observed with Mg2+, indicating that non-specific electrostatic interactions drive the conformational transition, although results also suggest that Na+ and Mg2+ may associate with TAR in distinct modes. The transition can be rationalized based on a population-weighted average of two ensembles comprising an electrostatically relaxed bent and flexible TAR conformation that is weakly associated with counterions, and a globally rigid coaxial conformation which has stronger electrostatic potential and association with counterions. The TAR inter-helical orientations that are stabilized by small molecules fall around the metal-induced conformational pathway, indicating that counterions may help predispose the TAR conformation for target recognition. Our results underscore the intricate sensitivity of RNA conformational dynamics to environmental conditions and demonstrate the ability to detect subtle conformational changes using NMR RDCs. PMID:17488097

Selected constituents in the smokes of foreign commercial cigaretts: tar, nicotine, carbon monoxide, and carbon dioxide

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

Jenkins, R.A.; Quincy, R.B.; Guerin, M.R.

The tar, nicotine, carbon monoxide, and carbon dioxide contents of the smokes of 220 brands of foreign commercial cigarettes are reported. In some instances, filter cigarettes of certain brands were found to deliver as much or more smoke constituents than their nonfilter counterparts. Also, data indicated that there can be a great variation in the tar, nicotine, or carbon monoxide content of the smoke of samples of a given brand of cigarettes, depending on the nation in which they are purchased. 24 tables.

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

PubMed

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

Marine microbes rapidly adapt to consume ethane, propane, and butane within the dissolved hydrocarbon plume of a natural seep

NASA Astrophysics Data System (ADS)

Mendes, Stephanie D.; Redmond, Molly C.; Voigritter, Karl; Perez, Christian; Scarlett, Rachel; Valentine, David L.

2015-03-01

Simple hydrocarbon gases containing two to four carbons (ethane, propane, and butane) are among the most abundant compounds present in petroleum reservoirs, and are introduced into the ocean through natural seepage and industrial discharge. Yet little is known about the bacterial consumption of these compounds in ocean waters. To assess the timing by which microbes metabolize these gases, we conducted a three-phase study that tested and applied a radiotracer-based method to quantify the oxidation rates of ethane, propane, and butane in fresh seawater samples. Phase 1 involved the synthesis of tritiated ethane, propane, and butane using Grignard reagents and tritiated water. Phase 2 was a systematic assessment of experimental conditions, wherein the indigenous microbial community was found to rapidly oxidize ethane, propane, and butane. Phase 3 was the application of this tritium method near the Coal Oil Point seeps, offshore California. Spatial and temporal patterns of ethane, propane, and butane oxidation down current from the hydrocarbon seeps demonstrated that >99% of these gases are metabolized within 1.3 days following initial exposure. The oxidation of ethane outpaced oxidation of propane and butane with patterns indicating the microbial community responded to these gases by rapid adaptation or growth. Methane oxidation responded the slowest in plume waters. Estimates based on the observed metabolic rates and carbon mass balance suggest that ethane, propane, and butane-consuming microorganisms may transiently account for a majority of the total microbial community in these impacted waters.

A comparative molecular and isotopic investigation of seep carbonates from mussel and tubeworm environments of the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Feng, D.; Guan, H.; Wu, N.; Chen, D.

2017-12-01

At deep-sea hydrocarbon seeps, macrofauna such as mussels and tubeworms and authigenic carbonate outcrops are common. It has been suggested that the distinct metabolic process of the macrofauna could modify the sedimentary geochemistry of their ambient environments. To better understand if the differences in the geochemical environments of mussels and tubeworms can be archived in the associated carbonates, lipid biomarker inventory and compound-specific isotopes of the carbonates from mussel and tubeworm environments from two seep sites were analyzed. The large δ13C offset (-32‰) of SRB-derived fatty acids (FAs) between tubeworm and mussel carbonates were partially attributed to the distinct effects on isotope fraction by specific metabolic process of the macrofauna. In such processes, the isotope fraction of chemosynthetic symbionts and physical action of mussel activities could result in local 13C enrichment, whereas the sufficient sulfate released through the tubeworm roots resulting in a persistent production of methane-derived bicarbonate and the enrichment of lighter carbon at subsurface sediments. Compared to mussel carbonates, the significantly higher concentrations of DAGEs and FAs as well as the smaller δ13C offset (Δδ13CDAGEs-FAs) than that of the mussel carbonates, suggest that the DAGEs and at least part of FAs found in tubeworm carbonates biosynthesized by SRB species other than DSS cluster. This DAGE-producing SRB is most likely involved in the hydrogen-driven SR instead of methane-fueled SR because a variety of SRB other than members of DSS cluster on hydrogen was isolated in presence of ANME-1 assemblage. The substantial amounts of DAGEs with strong 13C-depletions in tubeworm ecosystem may provide an important clue for their sources and role in the AOM process.

Late Pleistocene to Holocene sedimentation and hydrocarbon seeps on the continental shelf of a steep, tectonically active margin, southern California, USA

USGS Publications Warehouse

Draut, Amy E.; Hart, Patrick E.; Lorenson, T.D.; Ryan, Holly F.; Wong, Florence L.; Sliter, Ray W.; Conrad, James E.

2009-01-01

Small, steep, uplifting coastal watersheds are prolific sediment producers that contribute significantly to the global marine sediment budget. This study illustrates how sedimentation evolves in one such system where the continental shelf is largely sediment-starved, with most terrestrial sediment bypassing the shelf in favor of deposition in deeper basins. The Santa Barbara-Ventura coast of southern California, USA, is considered a classic area for the study of active tectonics and of Tertiary and Quaternary climatic evolution, interpretations of which depend upon an understanding of sedimentation patterns. High-resolution seismic-reflection data over >570 km2 of this shelf show that sediment production is concentrated in a few drainage basins, with the Ventura and Santa Clara River deltas containing most of the upper Pleistocene to Holocene sediment on the shelf. Away from those deltas, the major factor controlling shelf sedimentation is the interaction of wave energy with coastline geometry. Depocenters containing sediment 5-20 m thick exist opposite broad coastal embayments, whereas relict material (bedrock below a regional unconformity) is exposed at the sea floor in areas of the shelf opposite coastal headlands. Locally, natural hydrocarbon seeps interact with sediment deposition either to produce elevated tar-and-sediment mounds or as gas plumes that hinder sediment settling. As much as 80% of fluvial sediment delivered by the Ventura and Santa Clara Rivers is transported off the shelf (some into the Santa Barbara Basin and some into the Santa Monica Basin via Hueneme Canyon), leaving a shelf with relatively little recent sediment accumulation. Understanding factors that control large-scale sediment dispersal along a rapidly uplifting coast that produces substantial quantities of sediment has implications for interpreting the ancient stratigraphic record of active and transform continental margins, and for inferring the distribution of hydrocarbon resources

Heating tar sands formations while controlling pressure

DOEpatents

Stegemeier, George Leo [Houston, TX; Beer, Gary Lee [Houston, TX; Zhang, Etuan [Houston, TX

2010-01-12

Methods for treating a tar sands formation are described herein. Methods may include heating at least a section of a hydrocarbon layer in the formation from a plurality of heaters located in the formation. A pressure in the majority of the section may be maintained below a fracture pressure of the formation. The pressure in the majority of the section may be reduced to a selected pressure after the average temperature reaches a temperature that is above 240.degree. C. and is at or below pyrolysis temperatures of hydrocarbons in the section. At least some hydrocarbon fluids may be produced from the formation.

Authigenic minerals related to carbon and sulfur biogeochemical cycling from deep-sea active methane seeps offshore South-West Africa

NASA Astrophysics Data System (ADS)

Pierre, C.; Blanc-Valleron, M.; Demange, J.; Boudouma, O.; Pape, T.; Himmler, T.; Fekete, N.; Spiess, V.

2011-12-01

The South-West African continental margin is well known for occurrences of active methane-rich fluid seeps that are associated with seafloor pockmarks in a broad range of water depths, from the shelf to the deep basins. High gas flares in the water column, luxurious oases of benthic fauna, gas hydrate accumulations and diagenetic carbonate crusts have been observed at these seeps. During the M76/3a expedition of R/V METEOR (summer 2008) gravity cores recovered abundant authigenic carbonate concretions from five pockmarks of the South-West African margin including previously studied sites (Hydrate Hole, Worm Hole, Regab Pockmark) and two sites (Deep Hole, Baboon Cluster) newly discovered during the cruise. Carbonate concretions were mostly associated to sediments settled by seep-associated benthic macrofauna and bearing shallow gas hydrates. We present new results of the comprehensive analysis of the mineralogy and isotope geochemistry of the diagenetic carbonates sampled in the five pockmarks. The mineralogy of authigenic carbonates is dominated by magnesian calcite and aragonite, associated occasionally with dolomite. The oxygen and carbon isotopic compositions of authigenic carbonates (+2.4 < δ18O % V-PDB < +6.2 ; -61.0 < δ13C % V-PDB < -40.1) indicate that microbial anaerobic oxidation of methane (AOM) was the main process controling carbonate precipitation within sub-seafloor sediments deposited from the glacial-time up to the present. The frequent occurrence of diagenetic gypsum crystals within the sediments demonstrates that bio-irrigation with oxygenated bottom water by the burrowing activity of benthic fauna caused the secondary oxidation of reduced sulfur (hydrogen sulfide and pyrite) that was produced by sulfate reducting bacteria as a by-product of AOM; during the sulfide oxidation process, the released acidity induced the partial dissolution of carbonates. Our results demonstrate also the strong link that existed between the carbon and sulfur cycles

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

NASA Astrophysics Data System (ADS)

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.

A Long-Term Cultivation of an Anaerobic Methane-Oxidizing Microbial Community from Deep-Sea Methane-Seep Sediment Using a Continuous-Flow Bioreactor

PubMed Central

Aoki, Masataka; Ehara, Masayuki; Saito, Yumi; Yoshioka, Hideyoshi; Miyazaki, Masayuki; Saito, Yayoi; Miyashita, Ai; Kawakami, Shuji; Yamaguchi, Takashi; Ohashi, Akiyoshi; Nunoura, Takuro; Takai, Ken; Imachi, Hiroyuki

2014-01-01

Anaerobic oxidation of methane (AOM) in marine sediments is an important global methane sink, but the physiological characteristics of AOM-associated microorganisms remain poorly understood. Here we report the cultivation of an AOM microbial community from deep-sea methane-seep sediment using a continuous-flow bioreactor with polyurethane sponges, called the down-flow hanging sponge (DHS) bioreactor. We anaerobically incubated deep-sea methane-seep sediment collected from the Nankai Trough, Japan, for 2,013 days in the bioreactor at 10°C. Following incubation, an active AOM activity was confirmed by a tracer experiment using 13C-labeled methane. Phylogenetic analyses demonstrated that phylogenetically diverse Archaea and Bacteria grew in the bioreactor. After 2,013 days of incubation, the predominant archaeal components were anaerobic methanotroph (ANME)-2a, Deep-Sea Archaeal Group, and Marine Benthic Group-D, and Gammaproteobacteria was the dominant bacterial lineage. Fluorescence in situ hybridization analysis showed that ANME-1 and -2a, and most ANME-2c cells occurred without close physical interaction with potential bacterial partners. Our data demonstrate that the DHS bioreactor system is a useful system for cultivating fastidious methane-seep-associated sedimentary microorganisms. PMID:25141130

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

PubMed

Doya, Carolina; Chatzievangelou, Damianos; Bahamon, Nixon; Purser, Autun; De Leo, Fabio C; Juniper, S Kim; Thomsen, Laurenz; Aguzzi, Jacopo

2017-01-01

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 grooved tanner

Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement

USGS Publications Warehouse

Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

2012-01-01

Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10–4, as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10–5. Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0–6 years of age).

Comprehensive Understanding of the Shinkai Seep Field in the Southern Mariana Forearc Based On High-Resolution Bathymetry Data

NASA Astrophysics Data System (ADS)

Ohara, Y.; Okumura, T.; Stern, R. J.; Fujii, M.; Kasaya, T.; Martinez, F.; Michibayashi, K.

2016-12-01

The Shinkai Seep Field (SSF) is a serpentinite-hosted cold seep and associated ecosystem in the southern Mariana forearc near the Challenger Deep [Ohara et al., PNAS, 2012] discovered as a massive vesicomyid clam colony site by a DSV Shinkai 6500 dive in September 2010. Serpentinite-hosted alkaline seep system is believed to be important for considering the habitats of the earliest life on Earth as well as extraterrestrial life such as on Saturn's moon Enceladus. SSF is the fourth known major location of such a serpentinite-hosted alkaline seep system, following the Lost City Field in the Mid-Atlantic Ridge, South Chamorro Seamount in the Mariana Forearc, and the Prony Bay Field in New Caledonia. Following SSF discovery, three JAMSTEC expeditions with DSV Shinaki 6500 and a single NSF-funded US expedition with a deep-towed side-scan sonar IMI-30 investigated the SSF. These follow-up expeditions further discovered brucite and carbonate chimney sites and another vesicomyid clam colony sites [Okumura et al., submitted], locating the geographical positions for these sites. We now estimate that the areal extent of the SSF is approximately 500 m by 300 m. However, this estimation is based on the shipboard multibeam bathymetry of R/V Yokosuka, which has the grid size of approximately 50 m. Therefore, our understanding of the spatial relationships of chimneys and colonies is not as well-constrained as it could be, hindering to discuss the subseafloor hydrological structure of the SSF. In order to advance our understanding of the SSF, we need to directly sample the fluid and understand the detailed spatial relationship between SSF chimneys. We will have an expedition using JAMSTEC's R/V Kairei and ROV Kaiko Mk-IV in early November (KR16-14 cruise) to obtain this information. Near-bottom high-resolution bathymetric data (submeter-scale) of the SSF and the forearc rift in the vicinity of the SSF will be obtained with a multibeam sonar SeaBat 7125 system to be installed on the

Comprehensive GC²/MS for the monitoring of aromatic tar oil constituents during biodegradation in a historically contaminated soil.

PubMed

Vasilieva, Viktoriya; Scherr, Kerstin E; Edelmann, Eva; Hasinger, Marion; Loibner, Andreas P

2012-02-20

The constituents of tar oil comprise a wide range of physico-chemically heterogeneous pollutants of environmental concern. Besides the sixteen polycyclic aromatic hydrocarbons defined as priority pollutants by the US-EPA (EPA-PAHs), a wide range of substituted (NSO-PAC) and alkylated (alkyl-PAC) aromatic tar oil compounds are gaining increased attention for their toxic, carcinogenic, mutagenic and/or teratogenic properties. Investigations on tar oil biodegradation in soil are in part hampered by the absence of an efficient analytical tool for the simultaneous analysis of this wide range of compounds with dissimilar analytical properties. Therefore, the present study sets out to explore the applicability of comprehensive two-dimensional gas chromatography (GC²/MS) for the simultaneous measurement of compounds with differing polarity or that are co-eluting in one-dimensional systems. Aerobic tar oil biodegradation in a historically contaminated soil was analyzed over 56 days in lab-scale bioslurry tests. Forty-three aromatic compounds were identified with GC²/MS in one single analysis. The number of alkyl chains on a molecule was found to prime over alkyl chain length in hampering compound biodegradation. In most cases, substitution of carbon with nitrogen and oxygen was related to increased compound degradation in comparison to unalkylated and sulphur- or unsubstituted PAH with a similar ring number.The obtained results indicate that GC²/MS can be employed for the rapid assessment of a large variety of structurally heterogeneous environmental contaminants. Its application can contribute to facilitate site assessment, development and control of microbial cleanup technologies for tar oil contaminated sites. Copyright © 2011 Elsevier B.V. All rights reserved.

An NMR (Nuclear Magnetic Resonance) Investigation of the Chemical Association and Molecular Dynamics in Asphalt Ridge Tar Sand Ore and Bitumen

DOE R&D Accomplishments Database

Netzel, D. A.; Coover, P. T.

1987-09-01

Preliminary studies on tar sand bitumen given in this report have shown that the reassociation of tar sand bitumen to its original molecular configuration after thermal stressing is a first-order process requiring nearly a week to establish equilibrium. Studies were also conducted on the dissolution of tar sand bitumen in solvents of varying polarity. At a high-weight fraction of solute to solvent the apparent molecular weight of the bitumen molecules was greater than that of the original bitumen when dissolved in chloroform-d{sub 1} and benzene-d{sub 6}. This increase in the apparent molecular weight may be due to micellar formation or a weak solute-solvent molecular complex. Upon further dilution with any of the solvents studied, the apparent molecular weight of the tar sand bitumen decreased because of reduced van der Waals forces of interaction and/or hydrogen bonding. To define the exact nature of the interactions, it will be necessary to have viscosity measurements of the solutions.

Microbial Diversity in Deep-sea Methane Seep Sediments Presented by SSU rRNA Gene Tag Sequencing

PubMed Central

Nunoura, Takuro; Takaki, Yoshihiro; Kazama, Hiromi; Hirai, Miho; Ashi, Juichiro; Imachi, Hiroyuki; Takai, Ken

2012-01-01

Microbial community structures in methane seep sediments in the Nankai Trough were analyzed by tag-sequencing analysis for the small subunit (SSU) rRNA gene using a newly developed primer set. The dominant members of Archaea were Deep-sea Hydrothermal Vent Euryarchaeotic Group 6 (DHVEG 6), Marine Group I (MGI) and Deep Sea Archaeal Group (DSAG), and those in Bacteria were Alpha-, Gamma-, Delta- and Epsilonproteobacteria, Chloroflexi, Bacteroidetes, Planctomycetes and Acidobacteria. Diversity and richness were examined by 8,709 and 7,690 tag-sequences from sediments at 5 and 25 cm below the seafloor (cmbsf), respectively. The estimated diversity and richness in the methane seep sediment are as high as those in soil and deep-sea hydrothermal environments, although the tag-sequences obtained in this study were not sufficient to show whole microbial diversity in this analysis. We also compared the diversity and richness of each taxon/division between the sediments from the two depths, and found that the diversity and richness of some taxa/divisions varied significantly along with the depth. PMID:22510646

Impact of natural oil and higher hydrocarbons on microbial diversity, distribution, and activity in Gulf of Mexico cold-seep sediments

NASA Astrophysics Data System (ADS)

Orcutt, Beth N.; Joye, Samantha B.; Kleindienst, Sara; Knittel, Katrin; Ramette, Alban; Reitz, Anja; Samarkin, Vladimir; Treude, Tina; Boetius, Antje

2010-11-01

Gulf of Mexico cold seeps characterized by variable compositions and magnitudes of hydrocarbon seepage were sampled in order to investigate the effects of natural oils, methane, and non-methane hydrocarbons on microbial activity, diversity, and distribution in seafloor sediments. Though some sediments were characterized by relatively high quantities of oil, which may be toxic to some microorganisms, high rates of sulfate reduction (SR, 27.9±14.7 mmol m-2 d-1), anaerobic oxidation of methane (AOM, 16.2±6.7 mmol m-2 d-1), and acetate oxidation (2.74±0.76 mmol m-2 d-1) were observed in radiotracer measurements. In many instances, the SR rate was higher than the AOM rate, indicating that non-methane hydrocarbons fueled SR. Analysis of 16S rRNA gene clone libraries revealed phylogenetically diverse communities that were dominated by phylotypes of sulfate-reducing bacteria (SRB) and anaerobic methanotrophs of the ANME-1 and ANME-2 varieties. Another group of archaea form a Gulf of Mexico-specific clade (GOM ARC2) that may be important in brine-influenced, oil-impacted sediments from deeper water. Additionally, species grouping within the uncultivated Deltaproteobacteria clades SEEP-SRB3 and -SRB4, as well as relatives of Desulfobacterium anilini, were observed in relatively higher abundance in the oil-impacted sediments, suggesting that these groups of SRB may be involved in or influenced by degradation of higher hydrocarbons or petroleum byproducts.

Changes in tar yields and cigarette design in samples of Chinese cigarettes, 2009 and 2012

PubMed Central

Schneller, Liane M.; Zwierzchowski, Benjamin A.; Caruso, Rosalie V.; Li, Qiang; Yuan, Jiang; Fong, Geoffrey T.; O'Connor, Richard J.

2015-01-01

BACKGROUND China is home to both the greatest number of smokers and the greatest number of smoking-related deaths. An active and growing market of cigarettes marketed as “light” or “low tar” may keep health-concerned smokers from quitting, wrongly believing that such brands are less harmful. OBJECTIVE This study sought to observe changes in cigarette design characteristics and reported tar, nicotine and carbon monoxide (TNCO) levels in a sample of cigarette brands obtained in seven Chinese cities from 2009 and 2012. METHODS Cigarettes were purchased and shipped to Roswell Park Cancer Institute, where 91 pairs of packs were selected for physical cigarette design characteristic testing and recording of TNCO values. Data analysis was conducted using SPSS, and was initially characterized using descriptive statistics, correlations and generalized estimating equations to observe changes in brand varieties over time. FINDINGS Reported TNCO values on packs saw mean tar, nicotine and CO levels decrease from 2009 to 2012 by 7.9%, 4.5% and 6.0%, respectively. Ventilation was the only cigarette design feature that significantly changed over time (p < 0.001), with an increase of 31.7%. Significant predictors of tar and CO yields overall were ventilation and per-cigarette tobacco weight, while for nicotine tobacco moisture was also an independent predictor of yield. CONCLUSION The use of ventilation to decrease TNCO emissions is misleading smokers to believe that they are smoking a “light/low” tar cigarette that is healthier, and is potentially forestalling the quitting behaviors that would begin to reduce the health burden of tobacco in China, and so should be prohibited. PMID:25352560

Association of daily tar and nicotine intake with incident myocardial infarction: Results from the population-based MONICA/KORA Augsburg Cohort Study 1984 - 2002

PubMed Central

2011-01-01

Background Cigarette smoking has been shown to be one of the most important risk factors for cardiovascular diseases. However, little is known about cumulative effects of daily tar and nicotine intake on the risk of incident myocardial infarction (MI) so far. To bridge this gap, we conducted an analysis in a large prospective study from Southern Germany investigating associations of daily tar and nicotine intake with an incident MI event. Methods The study was based on 4,099 men and 4,197 women participating in two population-based MONICA Augsburg surveys between 1984 and 1990 and followed up within the KORA framework until 2002. During a mean follow-up of 13.3 years, a number of 307 men and 80 women developed an incident MI event. Relative risks were calculated as hazard ratios (HRs) estimated by Cox proportional hazards models adjusted for cardiovascular risk factors. Results In the present study, male regular smokers consumed on average more cigarettes per day than female regular smokers (20 versus 15) and had a higher tar and nicotine intake per day. In men, the MI risk compared to never-smokers increased with higher tar intake: HRs were 2.24 (95% CI 1.40-3.56) for 1-129 mg/day, 2.12 (95% CI 1.37-3.29) for 130-259 mg/day and 3.01 (95% CI 2.08-4.36) for ≥ 260 mg/day. In women, the corresponding associations were comparable but more pronounced for high tar intake (HR 4.67, 95% CI 1.76-12.40). Similar associations were observed for nicotine intake. Conclusions The present study based on a large population-based sample adds important evidence of cumulative effects of tar and nicotine intake on the risk of incident MI. Even low or medium tar and nicotine intake revealed substantial risk increases as compared to never-smokers. Therefore, reduction of tar and nicotine contents in cigarettes cannot be seen as a suitable public health policy in preventing myocardial infarction. PMID:21542909

Analysis of pure tar substances (polycyclic aromatic hydrocarbons) in the gas stream using ultraviolet visible (UV-Vis) spectroscopy and multivariate curve resolution (MCR).

PubMed

Weide, Tobias; Guschin, Viktor; Becker, Wolfgang; Koelle, Sabine; Maier, Simon; Seidelt, Stephan

2015-01-01

The analysis of tar, mostly characterized as polycyclic aromatic hydrocarbons (PAHs), describes a topic that has been researched for years. An online analysis of tar in the gas stream in particular is needed to characterize the tar conversion or formation in the biomass gasification process. The online analysis in the gas is carried out with ultraviolet-visible (UV-Vis) spectroscopy (190-720 nm). This online analysis is performed with a measuring cell developed by the Fraunhofer Institute for Chemical Technology (ICT). To this day, online tar measurements using UV-Vis spectroscopy have not been carried out in detail. Therefore, PAHs are analyzed as follows. The measurements are split into different steps. The first step to prove the online method is to vaporize single tar substances. These experiments show that a qualitative analysis of PAHs in the gas stream with the used measurement setup is possible. Furthermore, it is shown that the method provides very exact results, so that a differentiation of various PAHs is possible. The next step is to vaporize a PAH mixture. This step consists of vaporizing five pure substances almost simultaneously. The interpretation of the resulting data is made using a chemometric interpretation method, the multivariate curve resolution (MCR). The verification of the calculated results is the main aim of this experiment. It has been shown that the tar mixture can be analyzed qualitatively and quantitatively (in arbitrary units) in detail using the MCR. Finally it is the main goal of this paper to show the first steps in the applicability of the UV-Vis spectroscopy and the measurement setup on online tar analysis in view of characterizing the biomass gasification process. Due to that, the gasification plant (at the laboratory scale), developed and constructed by the Fraunhofer ICT, has been used to vaporize these substances. Using this gasification plant for the experiments enables the usage of the measurement setup also for the

Tolerability and cosmetic acceptability of liquor carbonis distillate (coal tar) solution 15% as topical therapy for plaque psoriasis.

PubMed

Brouda, Irina; Edison, Brenda; Van Cott, Alicia; Green, Barbara A

2010-04-01

Although generally recognized as an effective therapy for psoriasis, coal tar therapy lost appeal in modern clinical practice due to poor patient acceptability of its aesthetic properties. A new liquor carbonis distillate (LCD) solution 15% (equivalent to coal tar 2.3%) that uses an evaporative and transparent vehicle, fragrance, and a dab-on applicator was developed. Cosmetic acceptability of the LCD solution was compared to calcipotriene cream 0.005% during a randomized, active-controlled, investigator-blinded clinical trial. Participants with moderate plaque psoriasis applied LCD solution or calcipotriene cream twice daily to body lesions for 12 weeks and then were followed for 6 additional weeks without treatment. Participants completed a cosmetic acceptability survey about their medications after starting therapy. Mean ratings for aesthetic and product performance attributes were high in both groups; however, more participants treated with LCD solution versus calcipotriene cream rated their product as more convenient and beneficial compared to prior psoriasis therapies. Ratings of the scent, staining, drying time, and dab-on applicator for the LCD solution were favorable. Participant experience with LCD solution in this study suggests that it is a cosmetically acceptable psoriasis treatment that is comparable to calcipotriene cream.

Methotrexate iontophoresis versus coal tar ointment in palmoplantar psoriasis: A pilot study.

PubMed

Haseena, K; George, Sandhya; Riyaz, Najeeba; Sasidharanpillai, Sarita; Puthussery, Paul V

2017-01-01

Palmoplantar psoriasis is often disabling and refractory to conventional therapy. Systemic drugs are indicated in its severe form, but side effects are a concern with their use. Methotrexate is one such systemic drug which is effective and cheap. To reduce systemic toxicity, methotrexate has been tried topically but results have been inconsistent due to poor drug penetration into the skin by passive diffusion. Iontophoresis may enhance its absorption and efficacy. To evaluate the efficacy and safety of topical methotrexate iontophoresis in comparison with coal tar ointment in the treatment of palmoplantar psoriasis. Thirty-one patients with palmar and/or plantar psoriasis were selected for the study and 28 patients completed it. The side having more severe involvement was treated while the other palm/sole served as a control. Iontophoresis using methotrexate solution was carried out on the study palm/sole with the injectable preparation of methotrexate (50 mg/2 ml) once a week for the first 4 weeks and subsequently every two weeks, for a total of six sittings. The control palm/sole was treated with coal tar ointment on other days. Erythema, scaling, induration and fissuring scores were noted in both groups before and after treatment. Both study and control groups showed decreases in scores but the reduction was more in the study group, the difference being statistically significant. Drawbacks of our study include the small sample size and the lack of follow-up. The study and control arms were not exactly matched and the study was not blinded. Methotrexate iontophoresis was safe and more effective than coal tar ointmentin palmoplantarpsoriasis.

Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea

NASA Astrophysics Data System (ADS)

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.

Relationship of respiratory symptoms and pulmonary function to tar, nicotine, and carbon monoxide yield of cigarettes

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

Krzyzanowski, M.; Sherrill, D.L.; Paoletti, P.

The data from consecutive surveys of the Tucson Epidemiologic Study (1981-1988) were used to evaluate the relationship in cigarette smokers of respiratory symptoms and pulmonary function to tar, nicotine, and carbon monoxide (CO) yields of the cigarette. There were 690 subjects who reported smoking regularly in at least one survey, over age 15. After adjustment for intensity and duration of smoking and for depth of inhalation, the risk of chronic phlegm, cough, and dyspnea were not related to the tar and nicotine yields. In 414 subjects with pulmonary function tested in at least one of the three surveys the spirometricmore » indices used were significantly related to the daily dose of tar, nicotine, and CO (product of the cigarette yield and daily number of cigarettes smoked). The effects were more pronounced for past than for current doses. However, the differentiation of pulmonary function due to various yields of cigarettes was small in comparison to the difference in pulmonary function between smokers and nonsmokers.« less

Adsorption of nicotine and tar from the mainstream smoke of cigarettes by oxidized carbon nanotubes

NASA Astrophysics Data System (ADS)

Chen, Zhigang; Zhang, Lisha; Tang, Yiwen; Jia, Zhijie

2006-02-01

The adsorption of nicotine and tar from the mainstream smoke (MS) by the filter tips filled respectively with oxidized carbon nanotubes (O-CNTs), activated carbon and zeolite (NaY) has been investigated. O-CNTs show exceptional removal efficiency and their adsorption mechanism is investigated. Capillary condensation of some ingredients from MS in the inner hole of O-CNTs is observed and may be the primary reason for their superior removal efficiency. The effect of O-CNTs mass on the removal efficiencies is also studied and the results show that about 20-30 mg O-CNTs per cigarette can effectively remove most of nicotine and tar.

Meta-analysis of lung cancer in asphalt roofing and paving workers with external adjustment for confounding by coal tar

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

Fayerweather, W.E.

2007-07-01

The study's objectives were to update Partanen's and Boffetta's 1994 meta-analysis of lung cancer among roofing and paving asphalt workers and explore the role of coal tar in explaining the statistical heterogeneity among these studies. Information retrieval strategies and eligibility criteria were defined for identifying the epidemiologic studies to be included in the analysis. The relative risk ratio (RR) for lung cancer was selected as the effect measure of interest. Coal tar bias factors were developed and used to externally adjust each eligible study's published RR for confounding by coal tar. The meta-Relative Risk (meta-RR) and its variance were estimatedmore » by general variance-based methods. Heterogeneity of the RRs was assessed by heterogeneity chi-square and I{sup 2} tests. The results from this update were similar to those in Partanen's and Boffetta's original meta-analysis. Although the meta-RRs for the roofers and the pavers were no longer statistically significantly different from one another, significant heterogeneity remained within each of the coal tar-adjusted sectors. Meta-analysis of non-experimental epidemiologic studies is subject to significant uncertainties as is externally correcting studies for confounding. Given these uncertainties, the specific quantitative estimates in this (or any similar) analysis must be viewed with caution. Nevertheless, this analysis provides support for the hypothesis proposed by several major reviewers that confounding by coal tar-related PAH exposures may explain most or all of the lung cancer risks found in the epidemiologic literature on asphalt roofing and paving workers.« less

Observations of bubbles in natural seep flares at MC 118 and GC 600 using in situ quantitative imaging

NASA Astrophysics Data System (ADS)

Wang, Binbin; Socolofsky, Scott A.; Breier, John A.; Seewald, Jeffrey S.

2016-04-01

This paper reports the results of quantitative imaging using a stereoscopic, high-speed camera system at two natural gas seep sites in the northern Gulf of Mexico during the Gulf Integrated Spill Research G07 cruise in July 2014. The cruise was conducted on the E/V Nautilus using the ROV Hercules for in situ observation of the seeps as surrogates for the behavior of hydrocarbon bubbles in subsea blowouts. The seeps originated between 890 and 1190 m depth in Mississippi Canyon block 118 and Green Canyon block 600. The imaging system provided qualitative assessment of bubble behavior (e.g., breakup and coalescence) and verified the formation of clathrate hydrate skins on all bubbles above 1.3 m altitude. Quantitative image analysis yielded the bubble size distributions, rise velocity, total gas flux, and void fraction, with most measurements conducted from the seafloor to an altitude of 200 m. Bubble size distributions fit well to lognormal distributions, with median bubble sizes between 3 and 4.5 mm. Measurements of rise velocity fluctuated between two ranges: fast-rising bubbles following helical-type trajectories and bubbles rising about 40% slower following a zig-zag pattern. Rise speed was uncorrelated with hydrate formation, and bubbles following both speeds were observed at both sites. Ship-mounted multibeam sonar provided the flare rise heights, which corresponded closely with the boundary of the hydrate stability zone for the measured gas compositions. The evolution of bubble size with height agreed well with mass transfer rates predicted by equations for dirty bubbles.

48 CFR 1201.301-70 - Amendment of (TAR) 48 CFR chapter 12.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Amendment of (TAR) 48 CFR chapter 12. 1201.301-70 Section 1201.301-70 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Agency Acquisition Regulations 1201.301-70...

48 CFR 1201.301-70 - Amendment of (TAR) 48 CFR chapter 12.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Amendment of (TAR) 48 CFR chapter 12. 1201.301-70 Section 1201.301-70 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Agency Acquisition Regulations 1201.301-70...

48 CFR 1201.301-70 - Amendment of (TAR) 48 CFR chapter 12.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Amendment of (TAR) 48 CFR chapter 12. 1201.301-70 Section 1201.301-70 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Agency Acquisition Regulations 1201.301-70...

48 CFR 1201.301-70 - Amendment of (TAR) 48 CFR chapter 12.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Amendment of (TAR) 48 CFR chapter 12. 1201.301-70 Section 1201.301-70 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION GENERAL FEDERAL ACQUISITION REGULATIONS SYSTEM Agency Acquisition Regulations 1201.301-70...

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

NASA Astrophysics Data System (ADS)

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

Oxygenated Interface on Biomass Burn Tar Balls Determined bySingle Particle Scanning Transmission X-ray Microscopy

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

Tivanski, A.V.; Hopkins, R.J.; Tyliszczak, T.

2007-06-21

Carbonaceous particles originating from biomass burning canaccount for a large fraction of organic aerosols in a local environment.Presently, their composition, physical and chemical properties, as wellas their environmental effects are largely unknown. Tar balls, a distincttype of highly spherical carbonaceous biomass burn particles, have beenobserved in a number of field campaigns. The Yosemite AerosolCharacterization Study that took place in summer 2002 occurred during anactive fire season in the western United States; tar balls collectedduring this field campaign are described in this article. Scanningtransmission X-ray microscopy and near-edge X-ray absorption finestructure spectroscopy are used to determine the shape, structure, andsize-dependent chemicalmore » composition of ~;150 individual sphericalparticles ranging in size from 0.15 to 1.2mu m.The elemental compositionof tar balls is ~;55 percent atomic carbon and ~;45 percent atomicoxygen. Oxygen is present primarily as carboxylic carbonyls andoxygen-substituted alkyl (O-alkyl-C) functional groups, followed bymoderate amounts of ketonic carbonyls. The observed chemical composition,density, and carbon functional groups are distinctly different from sootor black carbon and more closely resemble high molecular weight polymerichumic-like substances, which could account for their reported opticalproperties. A detailed examination of the carboxylic carbonyl andO-alkyl-C functional groups as a function of particle size reveals a thinoxygenated interface layer. The high oxygen content, as well as thepresence of water-soluble carboxylic carbonyl groups, could account forthe reported hygroscopic properties of tar balls. The presence of theoxygenated layer is attributed to atmospheric processing of biomass burnparticles.« less

Non-Natural Linker Configuration in 2,6-Dipeptidyl-Anthraquinones Enhances the Inhibition of TAR RNA Binding/Annealing Activities by HIV-1 NC and Tat Proteins.

PubMed

Sosic, Alice; Saccone, Irene; Carraro, Caterina; Kenderdine, Thomas; Gamba, Elia; Caliendo, Giuseppe; Corvino, Angela; Di Vaio, Paola; Fiorino, Ferdinando; Magli, Elisa; Perissutti, Elisa; Santagada, Vincenzo; Severino, Beatrice; Spada, Valentina; Fabris, Dan; Frecentese, Francesco; Gatto, Barbara

2018-06-12

The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of anti-retrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidyl-anthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains. We show here that the non-natural linker configuration imparted unexpected TAR RNA targeting properties to the 2,6-peptidyl-anthraquinones and significantly enhanced their potency. Even if the new compounds were able to interact directly with the NC protein, they manifested a consistently higher affinity for the TAR RNA substrate and their TAR-binding properties mirrored their ability to interfere with NC-TAR interactions. Based on these findings, we propose that the viral Tat protein, sharing the same RNA substrate but acting in distinct phases of the viral life cycle, constitutes an additional druggable target for this class of peptidyl-anthraquinones. The inhibition of Tat-TAR interaction for the test compounds correlated again with their TAR-binding properties, while simultaneously failing to demonstrate any direct Tat-binding capabilities. These considerations highlighted the importance of TAR RNA in the elucidation of their inhibition mechanism, rather than direct protein inhibition. We have therefore identified anti-TAR compounds with dual in vitro inhibitory activity on different viral proteins, demonstrating that it is possible to develop multitarget compounds capable of interfering with processes mediated by the interactions of this essential RNA domain of HIV-1 genome with NC and Tat proteins.

The vesicomyid bivalve habitat at cold seeps supports heterogeneous and dynamic macrofaunal assemblages

NASA Astrophysics Data System (ADS)

Guillon, Erwan; Menot, Lénaïck; Decker, Carole; Krylova, Elena; Olu, Karine

2017-02-01

The high biodiversity found at cold seeps, despite elevated concentrations of methane and hydrogen sulfide, is attributed to multiple sources of habitat heterogeneity. In addition to geological and geochemical processes, biogenic habitats formed by large symbiont-bearing taxa, such as bivalves and siboglinid tubeworms, or by microbial mats drive the biodiversity of small-sized fauna. However, because these habitat-forming species also depend on geochemical gradients, the respective influence of abiotic and biotic factors in structuring associated macrofaunal communities is often unresolved. The giant pockmark Regab located at 3200 m depth on the Congo margin is characterized by different fluid-flow regimes, providing a mosaic of the most common biogenic habitats encountered at seeps: microbial mats, mussel beds, and vesicomyid clam beds; the latter being distributed along a gradient of environmental conditions from the center to the periphery of the pockmark. Here, we examined the structure of macrofaunal communities in biogenic habitats formed in soft sediment to (1) determine the influence of the habitats on the associated macrofaunal communities (inter-habitat comparison), (2) describe how macrofaunal communities vary among vesicomyid clam beds (intra-habitat comparison) and (3) assess the inter-annual variation in vesicomyid beds based on repeated sampling at a three-year interval. The highest densities were found in the microbial mat communities in intermediate fluid-flow areas, but they had low diversity - also observed in the sediment close to mussel beds. In contrast, vesicomyid beds harbored the highest diversity. The vesicomyid beds did not show a homogeneous macrofaunal community across sampled areas; instead, density and composition of macrofauna varied according to the location of the beds inside the pockmark. The clam bed sampled in the most active, central part of the pockmark resembled bacterial mat communities by the presence of highly sulfide

Dinitrogen and Cyanide Fixation by Methane Seep Microorganisms Revealed by FISH- SIMS And Implications for AOM Productivity and Nitrogenase Evolution

NASA Astrophysics Data System (ADS)

Dekas, A.; Orphan, V.

2008-12-01

The anaerobic oxidation of methane (AOM), mediated by methane oxidizing archaea (ANME) and sulfate reducing bacterial symbionts (SRB), minimizes the flux of methane from marine sediment to the overlying water column. Understanding the factors determining AOM productivity, and particularly the rates of methane catabolism and anabolism, is of interest to both modern and ancient investigations of climate and bulk carbon isotopic change. It has been hypothesized that nitrogen availability in methane seeps is temporally variable, and that the seep biomass may be at least partially nitrogen limited. The recent finding of nif genes, those necessary for the production of nitrogenase, in enrichments of ANME and SRB consortia suggested that the organisms mediating AOM have the potential to fix dinitrogen. In the present study we incubated methane seep sediment with nitrogen-deplete artificial marine media and a headspace of methane (CH4) and either 15N-labeled dinitrogen (15N2), cyanide (C15N-), or ammonia (15NH3) in order to (1) test the ability of these currently unculturable microorganisms to fix nitrogen and other triple bonded substrates, (2) investigate which AOM partner was responsible for the fixation, (3) compare growth rates on different nitrogen sources, and (4) characterize the phylogeny of these methane seep-associated nitrogenases. Fluorescence in situ hybridization coupled to nano-scale Secondary Ion Mass Spectroscopy imaging (FISH-SIMS) revealed incorporation of 15N into ANME and SRB biomass of up to 0.06 15N fractional abundance in the 15N2 incubation, and up to 0.02 in the C15N- incubation, after 6 and 4 months, respectively. This represents a nearly ten-fold enrichment of 15N compared to the measured natural 15N fractional abundance (0.0036). The NanoSIMS ion images of ANME/SRB aggregates from 15N2 incubations show evidence for 15N enrichment in both partners with the highest incorporation of 15N within the methanotrophic ANME cells. Cyanide incubations

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

NASA Astrophysics Data System (ADS)

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

Yields of tar, nicotine, and carbon monoxide in the sidestream smoke from 15 brands of Canadian cigarettes

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

Rickert, W.S.; Robinson, J.C.; Collishaw, N.

Sidestream smoke yields for 15 brands of cigarettes were determined under conditions where mainstream yields were approximately equal to those used for determining the values which appear on packages of Canadian cigarettes. Sidestream yields of tar, nicotine, and carbon monoxide were much higher than mainstream yields for all brands tested. The average sidestream-to-mainstream ratios for the 15 brands were 3.5, 6.6, and 6.8 for tar, nicotine, and carbon monoxide, respectively. The highest yields of sidestream were obtained from the brands with the lowest mainstream yields.

Microbiota associated with tubes of Escarpia sp. from cold seeps in the southwestern Atlantic Ocean constitutes a community distinct from that of surrounding marine sediment and water.

PubMed

Medina-Silva, Renata; Oliveira, Rafael R; Trindade, Fernanda J; Borges, Luiz G A; Lopes Simão, Taiz L; Augustin, Adolpho H; Valdez, Fernanda P; Constant, Marcelo J; Simundi, Carolina L; Eizirik, Eduardo; Groposo, Claudia; Miller, Dennis J; da Silva, Priscila Reis; Viana, Adriano R; Ketzer, João M M; Giongo, Adriana

2018-04-01

As the depth increases and the light fades in oceanic cold seeps, a variety of chemosynthetic-based benthic communities arise. Previous assessments reported polychaete annelids belonging to the family Siboglinidae as part of the fauna at cold seeps, with the 'Vestimentifera' clade containing specialists that depend on microbial chemosynthetic endosymbionts for nutrition. Little information exists concerning the microbiota of the external portion of the vestimentiferan trunk wall. We employed 16S rDNA-based metabarcoding to describe the external microbiota of the chitin tubes from the vestimentiferan Escarpia collected from a chemosynthetic community in a cold seep area at the southwestern Atlantic Ocean. The most abundant operational taxonomic unit (OTU) belonged to the family Pirellulaceae (phylum Planctomycetes), and the second most abundant OTU belonged to the order Methylococcales (phylum Proteobacteria), composing an average of 21.1 and 15.4% of the total reads on tubes, respectively. These frequencies contrasted with those from the surrounding environment (sediment and water), where they represent no more than 0.1% of the total reads each. Moreover, some taxa with lower abundances were detected only in Escarpia tube walls. These data constitute on the first report of an epibiont microbial community found in close association with external surface of a cold-seep metazoan, Escarpia sp., from a chemosynthetic community in the southwestern Atlantic Ocean.

Hydrocarbon biodegradation in hypersaline environments.

PubMed

Ward, D M; Brock, T D

1978-02-01

When mineral oil, hexadecane, and glutamate were added to natural samples of varying salinity (3.3 to 28.4%) from salt evaporation ponds and Great Salt Lake, Utah, rates of metabolism of these compounds decreased as salinity increased. Rate limitations did not appear to relate to low oxygen levels or to the availability of organic nutrients. Some oxidation of l-[U-C]glutamic acid occurred even at extreme salinities, whereas oxidation of [1-C]hexadecane was too low to be detected. Gas chromatographic examination of hexane-soluble components of tar samples from natural seeps at Rozel Point in Great Salt Lake demonstrated no evidence of biological oxidation of isoprenoid alkanes subject to degradation in normal environments. Some hexane-soluble components of the same tar were altered by incubation in a low-salinity enrichment culture inoculated with garden soil. Attempts to enrich for microorganisms in saline waters able to use mineral oil as a sole source of carbon and energy were successful below, but not above, about 20% salinity. This study strongly suggests a general reduction of metabolic rate at extreme salinities and raises doubt about the biodegradation of hydrocarbons in hypersaline environments.

Hydrocarbon Biodegradation in Hypersaline Environments

PubMed Central

Ward, David M.; Brock, T. D.

1978-01-01

When mineral oil, hexadecane, and glutamate were added to natural samples of varying salinity (3.3 to 28.4%) from salt evaporation ponds and Great Salt Lake, Utah, rates of metabolism of these compounds decreased as salinity increased. Rate limitations did not appear to relate to low oxygen levels or to the availability of organic nutrients. Some oxidation of l-[U-14C]glutamic acid occurred even at extreme salinities, whereas oxidation of [1-14C]hexadecane was too low to be detected. Gas chromatographic examination of hexane-soluble components of tar samples from natural seeps at Rozel Point in Great Salt Lake demonstrated no evidence of biological oxidation of isoprenoid alkanes subject to degradation in normal environments. Some hexane-soluble components of the same tar were altered by incubation in a low-salinity enrichment culture inoculated with garden soil. Attempts to enrich for microorganisms in saline waters able to use mineral oil as a sole source of carbon and energy were successful below, but not above, about 20% salinity. This study strongly suggests a general reduction of metabolic rate at extreme salinities and raises doubt about the biodegradation of hydrocarbons in hypersaline environments. PMID:16345276

Identification of novel methane-, ethane-, and propane-oxidizing bacteria at marine hydrocarbon seeps by stable isotope probing.

PubMed

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

2010-10-01

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 (13)C-labeled methane, ethane, or propane, we confirmed the incorporation of (13)C 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 (13)C-DNA revealed groups of microbes not previously thought to contribute to methane, ethane, or propane oxidation. First, (13)C 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, (13)C 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 (13)C-labeled DNA may encode an ethane monooxygenase. Third, (13)C 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.

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

USGS Publications Warehouse

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

A deep-sea, high-speed, stereoscopic imaging system for in situ measurement of natural seep bubble and droplet characteristics

NASA Astrophysics Data System (ADS)

Wang, Binbin; Socolofsky, Scott A.

2015-10-01

Development, testing, and application of a deep-sea, high-speed, stereoscopic imaging system are presented. The new system is designed for field-ready deployment, focusing on measurement of the characteristics of natural seep bubbles and droplets with high-speed and high-resolution image capture. The stereo view configuration allows precise evaluation of the physical scale of the moving particles in image pairs. Two laboratory validation experiments (a continuous bubble chain and an airstone bubble plume) were carried out to test the calibration procedure, performance of image processing and bubble matching algorithms, three-dimensional viewing, and estimation of bubble size distribution and volumetric flow rate. The results showed that the stereo view was able to improve the individual bubble size measurement over the single-camera view by up to 90% in the two validation cases, with the single-camera being biased toward overestimation of the flow rate. We also present the first application of this imaging system in a study of natural gas seeps in the Gulf of Mexico. The high-speed images reveal the rigidity of the transparent bubble interface, indicating the presence of clathrate hydrate skins on the natural gas bubbles near the source (lowest measurement 1.3 m above the vent). We estimated the dominant bubble size at the seep site Sleeping Dragon in Mississippi Canyon block 118 to be in the range of 2-4 mm and the volumetric flow rate to be 0.2-0.3 L/min during our measurements from 17 to 21 July 2014.

Morphology of First Zoeal Stage of Four Genera of Alvinocaridid Shrimps from Hydrothermal Vents and Cold Seeps: Implications for Ecology, Larval Biology and Phylogeny

PubMed Central

Hernández-Ávila, Iván; Cambon-Bonavita, Marie-Anne; Pradillon, Florence

2015-01-01