Microbial metabolism of tholin

NASA Astrophysics Data System (ADS)

Stoker, C. R.; Boston, P. J.; Mancinelli, R. L.; Segal, W.; Khare, B. N.; Sagan, C.

1990-05-01

In this paper, we show that a wide variety of common soil bacteria are able to obtain their carbon and energy needs from tholin (a class of complex organic heteropolymers thought to be widely distributed through the solar system; in this case tholin was produced by passage of electrical discharge through a mixture of methane, ammonia, and water vapor). We have isolated aerobic, anaerobic, and facultatively anaerobic bacteria which are able to use tholin as a sole carbon source. Organisms which metabolize tholin represent a variety of bacterial genera including Clostridium, Pseudomonas, Bacillus, Acinetobacter, Paracoccus, Alcaligenes, Micrococcus, Cornebacterium, Aerobacter, Arthrobacter, Flavobacterium,and Actinomyces. Aerobic tholin-using bacteria were firrst isolated from soils containing unusual or sparse carbon sources. Some of these organisms were found to be facultatively anaerobic. Strictly anaerobic tholin-using bacteria were isolated from both carbon-rich and carbon-poor anaerobic lake muds. In addition, both aerobic and anaerobic tholin-using bacteria were isolated from common soil collected outside the laboratory building. Some, but not all, of the strains that were able to obtain carbon from tholin were also able to obtain their nitrogen requirements from tholin. Bacteria isolated from common soils were tested for their ability to obtain carbon from the water-soluble fraction, the ethanol-soluble fraction, and the water/ethanol-insoluble fraction of the tholin. Of the 3.5 × 10 7 bacteria isolated per gram of common soils, 1.7 0.5, and 0.2%, respectively, were able to obtaib their carbon requirements from the water-soluble fraction, the ethanol-soluble fraction and the water/ethanol-insoluble fraction of the tholin. The palatability of tholins to modern microbes may have implications for the early evolution of microbial life on Earth. Tholins may have formed the base of the food chain for an early heterotrophic biosphere before the evolution of autotrophy on the early Earth. Where tholins are present on other planets, they could possibly be metabolized by contaminant microorganisms transported to these bodies via spacecraft. Thus, the presence of tholins should be taken into account when evaluating the planetary quarantine requirements for probes to other planets.

Seasonal variations in elemental carbon aerosol, carbon monoxide and sulfur dioxide: Implications for sources

NASA Astrophysics Data System (ADS)

Antony Chen, L.-W.; Doddridge, Bruce G.; Dickerson, Russell R.; Chow, Judith C.; Mueller, Peter K.; Quinn, John; Butler, William A.

As part of Maryland Aerosol Research and CHaracterization (MARCH-Atlantic) study, measurements of 24-hr average elemental carbon (EC) aerosol concentration were made at Fort Meade, Maryland, USA, a suburban site within the Baltimore-Washington corridor during July 1999, October 1999, January 2000, April 2000 and July 2000. Carbon monoxide (CO) and sulfur dioxide (SO2) were also measured nearly continuously over the period. Tight correlation between EC and CO in every month suggests common or proximate sources, likely traffic emissions. The EC versus CO slope varies in different seasons and generally increases with ambient temperature. The temperature dependence of EC/CO ratios suggests that EC source strength peaks in summer. By using the well established emission inventory for CO, and EC/CO ratio found in this study, EC emission over North America is estimated at 0.31±0.12 Tg yr-1, on the low end but in reasonable agreement with prior inventories based on emission factors and fuel consumption.

Seasonal variations in elemental carbon aerosol, carbon monoxide and sulfur dioxide: Implications for sources

NASA Astrophysics Data System (ADS)

Chen, L.-W. Antony; Doddridge, Bruce G.; Dickerson, Russell R.; Chow, Judith C.; Mueller, Peter K.; Quinn, John; Butler, William A.

2001-05-01

As part of Maryland Aerosol Research and CHaracterization (MARCH-Atlantic) study, measurements of 24-hr average elemental carbon (EC) aerosol concentration were made at Fort Meade, Maryland, USA, a suburban site within the Baltimore-Washington corridor during July 1999, October 1999, January 2000, April 2000 and July 2000. Carbon monoxide (CO) and sulfur dioxide (SO2) were also measured nearly continuously over the period. Tight correlation between EC and CO in every month suggests common or proximate sources, likely traffic emissions. The EC versus CO slope varies in different seasons and generally increases with ambient temperature. The temperature dependence of EC/CO ratios suggests that EC source strength peaks in summer. By using the well established emission inventory for CO, and EC/CO ratio found in this study, EC emission over North America is estimated at 0.31+/-0.12Tgyr-1, on the low end but in reasonable agreement with prior inventories based on emission factors and fuel consumption.

Matrix approach to uncertainty assessment and reduction for modeling terrestrial carbon cycle

NASA Astrophysics Data System (ADS)

Luo, Y.; Xia, J.; Ahlström, A.; Zhou, S.; Huang, Y.; Shi, Z.; Wang, Y.; Du, Z.; Lu, X.

2017-12-01

Terrestrial ecosystems absorb approximately 30% of the anthropogenic carbon dioxide emissions. This estimate has been deduced indirectly: combining analyses of atmospheric carbon dioxide concentrations with ocean observations to infer the net terrestrial carbon flux. In contrast, when knowledge about the terrestrial carbon cycle is integrated into different terrestrial carbon models they make widely different predictions. To improve the terrestrial carbon models, we have recently developed a matrix approach to uncertainty assessment and reduction. Specifically, the terrestrial carbon cycle has been commonly represented by a series of carbon balance equations to track carbon influxes into and effluxes out of individual pools in earth system models. This representation matches our understanding of carbon cycle processes well and can be reorganized into one matrix equation without changing any modeled carbon cycle processes and mechanisms. We have developed matrix equations of several global land C cycle models, including CLM3.5, 4.0 and 4.5, CABLE, LPJ-GUESS, and ORCHIDEE. Indeed, the matrix equation is generic and can be applied to other land carbon models. This matrix approach offers a suite of new diagnostic tools, such as the 3-dimensional (3-D) parameter space, traceability analysis, and variance decomposition, for uncertainty analysis. For example, predictions of carbon dynamics with complex land models can be placed in a 3-D parameter space (carbon input, residence time, and storage potential) as a common metric to measure how much model predictions are different. The latter can be traced to its source components by decomposing model predictions to a hierarchy of traceable components. Then, variance decomposition can help attribute the spread in predictions among multiple models to precisely identify sources of uncertainty. The highly uncertain components can be constrained by data as the matrix equation makes data assimilation computationally possible. We will illustrate various applications of this matrix approach to uncertainty assessment and reduction for terrestrial carbon cycle models.

Photoautotrophic microorganisms as a carbon source for temperate soil invertebrates.

PubMed

Schmidt, Olaf; Dyckmans, Jens; Schrader, Stefan

2016-01-01

We tested experimentally if photoautotrophic microorganisms are a carbon source for invertebrates in temperate soils. We exposed forest or arable soils to a (13)CO2-enriched atmosphere and quantified (13)C assimilation by three common animal groups: earthworms (Oligochaeta), springtails (Hexapoda) and slugs (Gastropoda). Endogeic earthworms (Allolobophora chlorotica) and hemiedaphic springtails (Ceratophysella denticulata) were highly (13)C enriched when incubated under light, deriving up to 3.0 and 17.0%, respectively, of their body carbon from the microbial source in 7 days. Earthworms assimilated more (13)C in undisturbed soil than when the microbial material was mixed into the soil, presumably reflecting selective surface grazing. By contrast, neither adult nor newly hatched terrestrial slugs (Deroceras reticulatum) grazed on algal mats. Non-photosynthetic (13)CO2 fixation in the dark was negligible. We conclude from these preliminary laboratory experiments that, in addition to litter and root-derived carbon from vascular plants, photoautotrophic soil surface microorganisms (cyanobacteria, algae) may be an ecologically important carbon input route for temperate soil animals that are traditionally assigned to the decomposer channel in soil food web models and carbon cycling studies. © 2016 The Author(s).

Mitigating climate change through small-scale forestry in the USA: opportunities and challenges

Treesearch

Susan Charnley; David Diaz; Hannah Gosnell

2010-01-01

Forest management for carbon sequestration is a low-cost, low-technology, relatively easy way to help mitigate global climate change that can be adopted now while additional long-term solutions are developed. Carbon-oriented management of forests also offers forest owners an opportunity to obtain a new source of income, and commonly has environmental co-benefits. The...

Variations in phytodetritus derived carbon uptake of the intertidal foraminifera Ammonia tepida and Haynesina germanica

NASA Astrophysics Data System (ADS)

Wukovits, Julia; Bukenberger, Patrick; Enge, Annekatrin; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

2016-04-01

Phytodetritus represents a major component of particulate organic carbon in intertidal mudflats. Estuaries and tidal currents yield an extensive amount of these particles that display a substantial nutrient source for littoral food webs. For benthic foraminifera, a group of marine protists, phytodetritus serves as the main food source. Foraminifera are considered to play a significant role in marine carbon turnover processes and show seasonally very high population densities in intertidal sediments. Therefore, it is important to gather explicit data about the specific carbon uptake behavior of intertidal foraminiferal species. In this study, laboratory feeding experiments were carried out to observe phytodetrital carbon uptake of foraminiferal specimen collected in the German Wadden Sea. Artificially produced phytodetritus was labelled with 13C to follow carbon ingestion into foraminiferal cytoplasm over time at different simulated conditions. The experiments were performed with monocultures under exclusion of other meiofauna. Chlorophyte detritus (Dunaliella tertiolecta) was fed to the two common species Ammonia tepida and Haynesina germanica. Ammonia tepida showed a significantly higher affinity to this food source than H. germanica. Testing the effect of temperature revealed a significant decrease of carbon ingestion with increasing temperature in H. germanica. Observations focusing on A. tepida showed a rising phytodetrital carbon content in the biomass of juvenile individuals in contrast to adult foraminifera. In general, carbon uptake reaches saturation levels a few hours after food supply. Furthermore, A. tepida benefits from constant availability of fresh food rather than from a high amount of phytodetritus derived from a single food pulse. Our investigations showed that the foraminiferal impact on intertidal processing of phytodetrital carbon sources is species specific, temperature related and depends on developmental stage and input dynamics. Additionally, the presented data reveal the quantitative level of food derived carbon gathered within foraminiferal biomass.

Very large release of mostly volcanic carbon during the Paleocene-Eocene Thermal Maximum

PubMed Central

Gutjahr, Marcus; Ridgwell, Andy; Sexton, Philip F.; Anagnostou, Eleni; Pearson, Paul N.; Pälike, Heiko; Norris, Richard D.; Thomas, Ellen; Foster, Gavin L.

2017-01-01

Global warming during the Palaeocene-Eocene Thermal Maximum1,2 (PETM, ~56 Ma) is commonly interpreted as being primarily driven by the destabilization of carbon from surficial sedimentary reservoirs such as methane hydrates3. However, the source(s) of carbon remain controversial1,3–5. Resolving this is key to understanding the proximal cause, as well as quantifying the roles of triggers versus feedbacks in driving the event. Here we present new boron isotope data – a proxy for seawater pH – that demonstrate the occurrence of persistently suppressed surface ocean pH across the PETM. Our pH data, alongside a paired carbon isotope record, are assimilated in an Earth system model to reconstruct the unfolding carbon cycle dynamics across the event6,7. We find strong evidence for a much larger (>10,000 PgC) and on average isotopically heavier carbon source than considered previously8,9. This leads us to identify volcanism associated with the North Atlantic Igneous Province, rather than carbon from a surficial reservoir, as the main driver of the PETM10,11. We also find that, although amplifying organic carbon feedbacks with climate likely played only a subordinate role in driving the event, enhanced organic matter burial was important in ultimately sequestering the released carbon and accelerating the recovery of the Earth system12. PMID:28858305

Garage carbon monoxide levels from sources commonly used in intentional poisoning.

PubMed

Hampson, Neil B; Holm, James R; Courtney, Todd G

2017-01-01

The incidence of intentional carbon monoxide (CO) poisoning is believed to have declined due to strict federal CO emissions standards for motor vehicles and the uniform application of catalytic converters (CC). We sought to compare ambient CO levels produced by automobiles with and without catalytic converters in a residential garage, as well as from other CO sources commonly used for intentional poisoning. CO levels were measured inside a freestanding 73 m3 one-car garage. CO sources included a 1971 automobile without CC, 2003 automobile with CC, charcoal grill, electrical generator, lawn mower and leaf blower. After 20 minutes of operation, the CO level in the garage was 253 PPM for the car without a catalytic converter and 30 PPM for the car equipped withone. CO levels after operating or burning the other sources were: charcoal 200 PPM; generator >999 PPM; lawn mower 198 PPM; and leaf blower 580 PPM. While emissions controls on automobiles have reduced intentional CO poisonings, alternate sources may produce CO at levels of the same magnitude as vehicles manufactured prior to the use of catalytic converters. Those involved in the care of potentially suicidal individuals should be aware of this.

Alluvial Mountain Meadow Source-Sink Dynamics: Land-Cover Effects on Water and Fluvial Carbon Export

NASA Astrophysics Data System (ADS)

Weiss, T.; Covino, T. P.; Wohl, E.; Rhoades, C.; Fegel, T.; Clow, D. W.

2017-12-01

Fluvial networks of historically glaciated mountain landscapes alternate between confined and unconfined valley segments. In low-gradient unconfined reaches, river-connected wet meadows commonly establish, and have been recognized as important locations of long-term water, carbon, and nutrient storage. Among connected meadow floodplains, sink-source behavior shifts as a function of flow state; storing water at high flows (snowmelt) and contributing toward higher late-season baseflows. Despite these benefits, historical and contemporary land-use practices often result in the simplification of wet meadow systems, leading to reduced river-floodplain connectivity, lower water-tables and reductions in hydrologic buffering capacity. In this study, we are exploring hydrologic-carbon relationships across a gradient of valley confinement and river-floodplain connectivity (connected, n=3; disconnected, n=4) within the Colorado Rockies. Our approach includes hydrologic analysis, fluorometric assays, water chemistry, instream metabolic measures, and land-cover assessment to examine patterns between land-form, carbon quantity and quality, and stream ecosystem productivity. Between different meadow types, preliminary results suggest differences between instream productivity, carbon qualities, and hydrologic-carbon sink-source dynamics across the season. These data and analyses will provide insight into water, carbon and nutrient flux dynamics as a function of land-cover in mountain headwaters.

Biological nitrate removal processes from drinking water supply-a review.

PubMed

Mohseni-Bandpi, Anoushiravan; Elliott, David Jack; Zazouli, Mohammad Ali

2013-12-19

This paper reviews both heterotrophic and autotrophic processes for the removal of nitrate from water supplies. The most commonly used carbon sources in heterotrophic denitrification are methanol, ethanol and acetic acid. Process performance for each feed stock is compared with particular reference nitrate and nitrite residual and to toxicity potential. Autotrophic nitrate removal has the advantages of not requiring an organic carbon source; however the slow growth rate of autotrophic bacteria and low nitrate removal rate have contributed to the fact that relatively few full scale plants are in operation at the present time.

Biological nitrate removal processes from drinking water supply-a review

PubMed Central

2013-01-01

This paper reviews both heterotrophic and autotrophic processes for the removal of nitrate from water supplies. The most commonly used carbon sources in heterotrophic denitrification are methanol, ethanol and acetic acid. Process performance for each feed stock is compared with particular reference nitrate and nitrite residual and to toxicity potential. Autotrophic nitrate removal has the advantages of not requiring an organic carbon source; however the slow growth rate of autotrophic bacteria and low nitrate removal rate have contributed to the fact that relatively few full scale plants are in operation at the present time. PMID:24355262

Fungal nutrient allocation in common mycorrhizal networks is regulated by the carbon source strength of individual host plants

USDA-ARS?s Scientific Manuscript database

• The common mycorrhizal networks (CMN) of arbuscular mycorrhizal (AM) fungi in the soil provide multiple host plants with nutrients, but the mechanisms by which the nutrient transport to individual host plants within one CMN is controlled, are currently unknown. • We followed by radioactive and st...

Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two hydrothermal vent fields in the Mid-Cayman rise

NASA Astrophysics Data System (ADS)

Streit, Kathrin; Bennett, Sarah A.; Van Dover, Cindy L.; Coleman, Max

2015-06-01

Hydrothermal vents harbor ecosystems mostly decoupled from organic carbon synthesized with the energy of sunlight (photosynthetic carbon source) but fueled instead by oxidation of reduced compounds to generate a chemosynthetic carbon source. Our study aimed to disentangle photosynthetic and chemosynthetic organic carbon sources for the shrimp species Rimicaris hybisae, a primary consumer presumed to obtain its organic carbon mainly from ectosymbiotic chemoautotrophic bacteria living on its gill cover membrane. To provide ectosymbionts with ideal conditions for chemosynthesis, these shrimp live in dense clusters around vent chimneys; they are, however, also found sparsely distributed adjacent to diffuse vent flows, where they might depend on alternative food sources. Densely and sparsely distributed shrimp were sampled and dissected into abdominal tissue and gill cover membrane, covered with ectosymbiotic bacteria, at two hydrothermal vent fields in the Mid-Cayman rise that differ in vent chemistry. Fatty acids (FA) were extracted from shrimp tissues and their carbon isotopic compositions assessed. The FA data indicate that adult R. hybisae predominantly rely on bacteria for their organic carbon needs. Their FA composition is dominated by common bacterial FA of the n7 family (~41%). Bacterial FA of the n4 FA family are also abundant and found to constitute good biomarkers for gill ectosymbionts. Sparsely distributed shrimp contain fractions of n4 FA in gill cover membranes ~4% lower than densely packed ones (~18%) and much higher fractions of photosynthetic FA in abdominal tissues, ~4% more (compared with 1.6%), suggesting replacement of ectosymbionts along with exoskeletons (molt), while they take up alternative diets of partly photosynthetic organic carbon. Abdominal tissues also contain photosynthetic FA from a second source taken up presumably during an early dispersal phase and still present to c. 3% in adult shrimp. The contribution of photosynthetic carbon to the FA pool of adult R. hybisae is, however, overall small (max. 8%). Significant differences in carbon isotopic values of chemosynthetically derived FA between vent fields suggest that different dominant C fixation pathways are being used.

Low carbon amendment rates during anaerobic soil disinfestation (ASD) at moderate soil temperatures do not decrease viability of Sclerotinia sclerotiorum sclerotia or Fusarium root rot of common bean

USDA-ARS?s Scientific Manuscript database

Anaerobic soil disinfestation (ASD; also termed biological soil disinfestation) is a non-chemical process which includes 1) soil incorporation of a labile carbon (C) source, 2) mulching with polyethylene film to limit gas exchange, and 3) drip irrigation to saturation of the topsoil or bedded area. ...

Tracing Carbon Sources through Aquatic and Terrestrial Food Webs Using Amino Acid Stable Isotope Fingerprinting

PubMed Central

Larsen, Thomas; Ventura, Marc; Andersen, Nils; O’Brien, Diane M.; Piatkowski, Uwe; McCarthy, Matthew D.

2013-01-01

Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ13C patterns among amino acids (δ13CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ13CAA patterns in contrast to bulk δ13C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ13CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ13C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ13C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs. PMID:24069196

Tracing carbon sources through aquatic and terrestrial food webs using amino acid stable isotope fingerprinting.

PubMed

Larsen, Thomas; Ventura, Marc; Andersen, Nils; O'Brien, Diane M; Piatkowski, Uwe; McCarthy, Matthew D

2013-01-01

Tracing the origin of nutrients is a fundamental goal of food web research but methodological issues associated with current research techniques such as using stable isotope ratios of bulk tissue can lead to confounding results. We investigated whether naturally occurring δ(13)C patterns among amino acids (δ(13)CAA) could distinguish between multiple aquatic and terrestrial primary production sources. We found that δ(13)CAA patterns in contrast to bulk δ(13)C values distinguished between carbon derived from algae, seagrass, terrestrial plants, bacteria and fungi. Furthermore, we showed for two aquatic producers that their δ(13)CAA patterns were largely unaffected by different environmental conditions despite substantial shifts in bulk δ(13)C values. The potential of assessing the major carbon sources at the base of the food web was demonstrated for freshwater, pelagic, and estuarine consumers; consumer δ(13)C patterns of essential amino acids largely matched those of the dominant primary producers in each system. Since amino acids make up about half of organismal carbon, source diagnostic isotope fingerprints can be used as a new complementary approach to overcome some of the limitations of variable source bulk isotope values commonly encountered in estuarine areas and other complex environments with mixed aquatic and terrestrial inputs.

A greenhouse gas source of surprising significance: anthropogenic CO2 emissions from use of methanol in sewage treatment.

PubMed

Willis, John L; Al-Omari, Ahmed; Bastian, Robert; Brower, Bill; DeBarbadillo, Christine; Murthy, Sudhir; Peot, Christopher; Yuan, Zhiguo

2017-05-01

The impact of methanol (CH 3 OH) as a source of anthropogenic carbon dioxide (CO 2 ) in denitrification at wastewater treatment plants (WWTPs) has never been quantified. CH 3 OH is the most commonly purchased carbon source for sewage denitrification. Until recently, greenhouse gas (GHG) reporting protocols consistently ignored the liberation of anthropogenic CO 2 attributable to CH 3 OH. This oversight can likely be attributed to a simplifying notion that CO 2 produced through activated-sludge-process respiration is biogenic because most raw-sewage carbon is un-sequestered prior to entering a WWTP. Instead, a biogenic categorization cannot apply to fossil-fuel-derived carbon sources like CH 3 OH. This paper provides a summary of how CH 3 OH use at DC Water's Blue Plains Advanced Wastewater Treatment Plant (AWTP; Washington, DC, USA) amounts to 60 to 85% of the AWTP's Scope-1 emissions. The United States Environmental Protection Agency and Water Environment Federation databases suggest that CH 3 OH CO 2 likely represents one quarter of all Scope-1 GHG emissions attributable to sewage treatment in the USA. Finally, many alternatives to CH 3 OH use exist and are discussed.

Authigenic carbonate formation at hydrocarbon seeps in continental margin sediments: A comparative study

USGS Publications Warehouse

Naehr, T.H.; Eichhubl, P.; Orphan, V.J.; Hovland, M.; Paull, C.K.; Ussler, W.; Lorenson, T.D.; Greene, H. Gary

2007-01-01

Authigenic carbonates from five continental margin locations, the Eel River Basin, Monterey Bay, Santa Barbara Basin, the Sea of Okhotsk, and the North Sea, exhibit a wide range of mineralogical and stable isotopic compositions. These precipitates include aragonite, low- and high-Mg calcite, and dolomite. The carbon isotopic composition of carbonates varies widely, ranging from -60??? to +26???, indicating complex carbon sources that include 13C-depleted microbial and thermogenic methane and residual, 13C-enriched, bicarbonate. A similarly large variability of ??18O values (-5.5??? to +8.9???) demonstrates the geochemical complexity of these sites, with some samples pointing toward an 18O-enriched oxygen source possibly related to advection of 18O-enriched formation water or to the decomposition of gas hydrate. Samples depleted in 18O are consistent with formation deeper in the sediment or mixing of pore fluids with meteoric water during carbonate precipitation. A wide range of isotopic and mineralogical variation in authigenic carbonate composition within individual study areas but common trends across multiple geographic areas suggest that these parameters alone are not indicative for certain tectonic or geochemical settings. Rather, the observed variations probably reflect local controls on the flux of carbon and other reduced ions, such as faults, fluid conduits, the presence or absence of gas hydrate in the sediment, and the temporal evolution of the local carbon reservoir. Areas with seafloor carbonates that indicate formation at greater depth below the sediment-water interface must have undergone uplift and erosion in the past or are still being uplifted. Consequently, the occurrence of carbonate slabs on the seafloor in areas of active hydrocarbon seepage is commonly an indicator of exhumation following carbonate precipitation in the shallow subsurface. Therefore, careful petrographic and geochemical analyses are critical components necessary for the correct interpretation of processes related to hydrocarbon seepage in continental margin environments and elsewhere. ?? 2007 Elsevier Ltd. All rights reserved.

Influence of carbohydrates on secondary metabolism in Fusarium avenaceum.

PubMed

Sørensen, Jens Laurids; Giese, Henriette

2013-09-24

Fusarium avenaceum is a widespread pathogen of important crops in the temperate climate zones that can produce many bioactive secondary metabolites, including moniliformin, fusarin C, antibiotic Y, 2-amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol), chlamydosporol, aurofusarin and enniatins. Here, we examine the production of these secondary metabolites in response to cultivation on different carbon sources in order to gain insight into the regulation and production of secondary metabolites in F. avenaceum. Seven monosaccharides (arabinose, xylose, fructose, sorbose, galactose, mannose, glucose), five disaccharides (cellobiose, lactose, maltose, sucrose and trehalose) and three polysaccharides (dextrin, inulin and xylan) were used as substrates. Three F. avenaceum strains were used in the experiments. These were all able to grow and produce aurofusarin on the tested carbon sources. Moniliformin and enniatins were produced on all carbon types, except on lactose, which suggest a common conserved regulation mechanism. Differences in the strains was observed for production of fusarin C, 2-AOD-3-ol, chlamydosporol and antibiotic Y, which suggests that carbon source plays a role in the regulation of their biosynthesis.

Depleted δ13C Values in Salt Dome Cap Rock Organic Matter and Implications for Microbial Metabolism and Fixation

NASA Astrophysics Data System (ADS)

Loyd, S. J.; Lu, L.; Caesar, K. H.; Kyle, R.

2015-12-01

Salt domes occur throughout the Gulf Coast Region USA and are often associated with trapped hydrocarbons. These salt domes can be capped by sulfate and carbonate minerals that result from complex digenetic interactions in the subsurface. The specific natures of these interactions are poorly understood, in particular the role of microbes in facilitating mineralization and element cycling. Carbon isotope compositions of cap rock calcites (δ13Ccarb) are highly variable and range from near neutral to less than -40‰ (VPDB) indicative of methane-sourced carbon. These low values and the common coexistence of elemental sulfur and metal sulfides have spurred hypotheses invoking microbial sulfate reduction as driving carbonate mineral authigenesis. Here, we present new organic carbon isotope (δ13Corg) data that, similar to δ13Ccarb, exhibit depletions below -30 to -25‰. These δ13Corg values are lower than local liquid hydrocarbons and "normal" marine organic matter reflecting either microbial fixation of methane-sourced carbon or microbial fractionation from liquid hydrocarbon sources. The combined carbon isotope data (δ13Ccarb and δ13Corg) indicate that methane likely plays an important role in microbial cycling in salt domes. The δ13Corg values are similar to those of anaerobic oxidation of methane (AOM) related communities from methane-sulfate controlled marine sediments. Ultimately, salt dome environments may share some important characteristics with AOM systems.

A New Biomarker Proxy for Palaeo-pCO2 Reconstruction in Ancient Sediments

NASA Astrophysics Data System (ADS)

Pancost, R. D.; Magness, S.; Maxwell, J. R.

2001-12-01

The carbon isotopic composition of marine organic matter has commonly been used in chemostratigraphy or as a proxy for ancient pCO2 levels. Both of these goals require that the source of organic matter be well defined, and in the case of palaeo-pCO2 investigations, the organic matter must be derived ultimately from aquatic photoautotrophs. However, additional sources, including terrestrial biomass, heterotrophs, or bacteria, can also contribute to total organic carbon (TOC). In the past decade, numerous workers have attempted to refine organic carbon isotope records using the isotopic composition of individual compounds (biomarkers) rather than the TOC. The appeal of this approach is that by examining specific biomarkers, a signal diagnostic for photoautotrophic organisms can be obtained. For compound-specific isotope analyses to be most effective, the compounds analysed must have a relatively specific source. Among the most commonly used biomarkers in palaeo-pCO2 investigations are alkenones, long-chain ketones derived exclusively from certain species of haptophyte algae. However, alkenones are absent in rocks older than the Jurassic and either absent or present in low abundances in rocks older than the Miocene. Thus, in older rocks, other biomarkers, including steranes (derived from eukaryotic sterols), phytane (presumably derived from chlorophyll), and n-alkanes (derived from algal macromolecules), are used. Unfortunately, these compounds can have alternative sources and become less reliable as isotopic proxies for photoautotrophs with increasing thermal maturity and complexity of the hydrocarbon distribution. Here we propose the use of a maleimides (1H-pyrrole-2,5-diones) as a new biomarker class for evaluating past changes in photoautotroph carbon isotopic compositions. Maleimides have three key advantages over other biomarkers in ancient rocks. First, they are degradation products of chlorophyll and have no known alternative origins in marine sediments. Second, because of their unique structure, they can be readily isolated from other organic components facilitating the determination of accurate carbon isotope ratios. Finally, the pyrrole structure is relatively stable insuring that maleimides survive even in thermally mature rocks. We have applied the analysis of maleimides to investigations of sediments from the Kupferschiefer (Permian), Vena del Gesso (Messinian) and Livello Bonarelli (Cenomanian-Turonian boundary) formations. In all three cases, the carbon isotopic compositions of selected maleimides exhibit shifts predicted by either carbonate or other biomarker carbon isotope profiles.

Biogeochemical snapshot of an urban water system: The Anacostia River, Washington DC

NASA Astrophysics Data System (ADS)

Macavoy, S.; Ewers, E.; Bushaw-Newton, K.

2007-12-01

Highly urbanized and contaminated with PAHs, heavy metals, and sewage, the Anacostia River flows through Maryland and Washington, DC into the tidal Potomac River. Efforts have been underway to assess the river's ecological integrity and to determine the extent of anthropogenic influences. This study examines the nutrients, bacterial biomarkers, organic material, and carbon, nitrogen and sulfur sources in the Anacostia. High biological oxygen demand and low nitrogen (0.33-0.56 mg /L)/phosphorus (0.014 - 0.021 mg/L) concentrations were observed in three areas of the river. Bacterial activity based on carbon source utilization was higher in sediment samples than in water column samples. While bacterial abundances were decreased in downstream areas of sediment; abundances increased in downstream areas in the water column. Downstream sites had higher nutrient concentrations and dissolved organic carbon (up to 13.7 mg/L). Odd-chain length and branched fatty acids (FAs) in the sediments indicated bacterial sources, but long chain FAs indicative of terrestrial primary production were also abundant in some sediments. Also dominant among methyl esters and ketones in some sediment and water column samples was methyl isobutyl ketone, a common industrial solvent and combustion by-product. Sediment carbon stable isotope analyses show a mix of autochthonous and allochthonous derived materials, but most carbon was derived from terrestrial sources (-23.3 to -31.7°). Sediment nitrogen stable isotopes ranged from -5.4 to. 5.6, showing nitrate uptake by plants and also recycling of nitrogen within the river. Sulfur sources were generally between 3 and -5, reflecting local sulfate sources and anaerobic sulfate reduction.

The origin of organic matter in the Martian meteorite ALH84001.

PubMed

Becker, L; Popp, B; Rust, T; Bada, J L

1999-01-01

Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C values for the organic matter associated with the carbonate globules averaged -26% and is attributed to terrestrial contamination. In contrast, the delta 13C values for the organic matter associated with the bulk matrix material yielded a value of -15%. The only common carbon sources on the Earth that yield similar delta 13C values, other then some diagenetically altered marine carbonates, are C4 plants. A delta 13C value of -15%, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery of meteoritic or cometary debris to the surface of Mars.

The origin of organic matter in the Martian meteorite ALH84001.

PubMed

Becker, L; Popp, B; Rust, T; Bada, J L

1999-03-30

Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C values for the organic matter associated with the carbonate globules averaged -26% and is attributed to terrestrial contamination. In contrast, the delta 13C values for the organic matter associated with the bulk matrix material yielded a value of -15%. The only common sources of carbon on the Earth that yield similar delta 13C values, other then some diagenetically altered marine carbonates, are C4 plants. A delta 13C value of -15%, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery, of meteoritic or cometary debris to the surface of Mars.

Sources and mobility of carbonate melts beneath cratons, with implications for deep carbon cycling, metasomatism and rift initiation

NASA Astrophysics Data System (ADS)

Tappe, Sebastian; Romer, Rolf L.; Stracke, Andreas; Steenfelt, Agnete; Smart, Katie A.; Muehlenbachs, Karlis; Torsvik, Trond H.

2017-05-01

Kimberlite and carbonatite magmas that intrude cratonic lithosphere are among the deepest probes of the terrestrial carbon cycle. Their co-existence on thick continental shields is commonly attributed to continuous partial melting sequences of carbonated peridotite at >150 km depths, possibly as deep as the mantle transition zone. At Tikiusaaq on the North Atlantic craton in West Greenland, approximately 160 Ma old ultrafresh kimberlite dykes and carbonatite sheets provide a rare opportunity to study the origin and evolution of carbonate-rich melts beneath cratons. Although their Sr-Nd-Hf-Pb-Li isotopic compositions suggest a common convecting upper mantle source that includes depleted and recycled oceanic crust components (e.g., negative ΔεHf coupled with > + 5 ‰ δ7Li), incompatible trace element modelling identifies only the kimberlites as near-primary low-degree partial melts (0.05-3%) of carbonated peridotite. In contrast, the trace element systematics of the carbonatites are difficult to reproduce by partial melting of carbonated peridotite, and the heavy carbon isotopic signatures (-3.6 to - 2.4 ‰ δ13C for carbonatites versus -5.7 to - 3.6 ‰ δ13C for kimberlites) require open-system fractionation at magmatic temperatures. Given that the oxidation state of Earth's mantle at >150 km depth is too reduced to enable larger volumes of 'pure' carbonate melt to migrate, it is reasonable to speculate that percolating near-solidus melts of carbonated peridotite must be silicate-dominated with only dilute carbonate contents, similar to the Tikiusaaq kimberlite compositions (e.g., 16-33 wt.% SiO2). This concept is supported by our findings from the North Atlantic craton where kimberlite and other deeply derived carbonated silicate melts, such as aillikites, exsolve their carbonate components within the shallow lithosphere en route to the Earth's surface, thereby producing carbonatite magmas. The relative abundances of trace elements of such highly differentiated 'cratonic carbonatites' have only little in common with those of metasomatic agents that act on the deeper lithosphere. Consequently, carbonatite trace element systematics should only be used with caution when constraining carbon mobility and metasomatism at mantle depths. Regardless of the exact nature of carbonate-bearing melts within the mantle lithosphere, they play an important role in enrichment processes, thereby decreasing the stability of buoyant cratons and promoting rift initiation - as exemplified by the Mesozoic-Cenozoic breakup of the North Atlantic craton.

An innovative wood-chip-framework substrate used as slow-release carbon source to treat high-strength nitrogen wastewater.

PubMed

Li, Huai; Chi, Zifang; Yan, Baixing; Cheng, Long; Li, Jianzheng

2017-01-01

Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems. However, nitrogen removal efficiency is usually limited due to the low carbon/nitrogen (C/N) ratio. A common solution is to add external carbon sources, but amount of liquid is difficult to determine. Therefore, a combined wood-chip-framework substrate (with wood, slag and gravel) as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem. Results show that the removal rate of ammonia nitrogen (NH 4 + -N), total nitrogen (TN) and chemical oxygen demand (COD) could reach 37.5%-85%, 57.4%-86%, 32.4%-78%, respectively, indicating the combined substrate could diffuse sufficient oxygen for the nitrification process (slag and gravel zone) and provide carbon source for denitrification process (wood-chip zone). The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip, respectively. Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process, while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process. This study provides a new idea for wetland treatment of high-strength nitrogen wastewater. Copyright © 2016. Published by Elsevier B.V.

Whole watershed quantification of net carbon fluxes by erosion and deposition within the Christina River Basin Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Aufdenkampe, A. K.; Karwan, D. L.; Aalto, R. E.; Marquard, J.; Yoo, K.; Wenell, B.; Chen, C.

2012-12-01

We have proposed that the rate at which fresh, carbon-free minerals are delivered to and mix with fresh organic matter determines the rate of carbon preservation at a watershed scale (Aufdenkampe et al. 2011). Although many studies have examined the role of erosion in carbon balances, none consider that fresh carbon and fresh minerals interact. We believe that this mechanism may be a dominant sequestration process in watersheds with strong anthropogenic impacts. Our hypothesis - that the rate of mixing fresh carbon with fresh, carbon-free minerals is a primary control on watershed-scale carbon sequestration - is central to our Christina River Basin Critical Zone Observatory project (CRB-CZO, http://www.udel.edu/czo/). The Christina River Basin spans 1440 km2 from piedmont to Atlantic coastal plain physiographic provinces in the states of Pennsylvania and Delaware, and experienced intensive deforestation and land use beginning in the colonial period of the USA. Here we present a synthesis of multi-disciplinary data from the CRB-CZO on materials as they are transported from sapprolite to topsoils to colluvium to suspended solids to floodplains, wetlands and eventually to the Delaware Bay estuary. At the heart of our analysis is a spatially-integrated, flux-weighted comparison of the organic carbon to mineral surface area ratio (OC/SA) of erosion source materials versus transported and deposited materials. Because source end-members - such as forest topsoils, farmed topsoils, gullied subsoils and stream banks - represent a wide distribution of initial, pre-erosion OC/SA, we quantify source contributions using geochemical sediment fingerprinting approaches (Walling 2005). Analytes used for sediment fingerprinting include: total mineral elemental composition (including rare earth elements), fallout radioisotope activity for common erosion tracers (beryllium-7, beryllium-10, lead-210, cesium-137), particle size distribution and mineral specific surface area, in addition to organic carbon and nitrogen content with stable isotope (13C, 15N) and radiocarbon (14C) abundance to quantify OC/SA and organic carbon sources and mean age. We then use multivariate mixing model analysis to quantify the fractional contribution of each source end-member to each sample of suspended or deposited sediments. Last, we calculate a predicted OC/SA based on source end-member mixing and compare to the measured OC/SA to quantify net change in mineral complexed carbon.

Accumulated analyses of amino acid precursors in returned lunar samples

NASA Technical Reports Server (NTRS)

Fox, S. W.; Harada, K.; Hare, P. E.

1973-01-01

Six amino acids (glycine, alanine, aspartic acid, glutamic acid, serine, and threonine) obtained by hydrolysis of extracts have been quantitatively determined in ten collections of fines from five Apollo missions. Although the amounts found, 7-45 ng/g, are small, the lunar amino acid/carbon ratios are comparable to those of the carbonaceous chondrites, Murchison and Murray, as analyzed by the same procedures. Since both the ratios of amino acid to carbon, and the four or five most common types of proteinous amino acid found, are comparable for the two extraterrestrial sources despite different cosmophysical histories of the moon and meteorites, common cosmochemical processes are suggested.

Elucidating the Role of Carbon Sources on Abiotic and Biotic Release of Arsenic into Cambodian Aquifers

NASA Astrophysics Data System (ADS)

Koeneke, M.

2017-12-01

Arsenic (As) is a naturally occurring contaminant in Cambodia that has been contaminating well-water sources of millions of people. Commonly, studies look into the biotic factors that cause the arsenic to be released from aquifer sediments to groundwater. However, abiotic release of As from sediments, though little studied, may also play key roles in As contamination of well water. The goal of this research is to quantitatively compare organic-carbon mediated abiotic and biotic release of arsenic from sediments to groundwater. Batch anaerobic incubation experiments under abiotic (sodium azide used to immobilize microbes) and biotic conditions were conducted using Cambodian aquifer sediments, four different organic carbon sources (sodium lactate, sodium citrate, sodium oxalate, and humic acid), and six different carbon concentrations (0, 1, 2.5, 5, 10, 25mg C/L). Dissolved arsenic, iron(Fe), and manganese(Mn) concentrations in the treatments were measured 112 days . In addition, sediment and solution carbon solution was measured . Collectively, these show how different carbon sources, different carbon concentrations, and how abiotic and biotic factors impact the release of arsenic from Cambodian sediments into aquifers. Overall, an introduction of organic carbon to the soil increases the amount of As released from the sediment. The biotic + abiotic and abiotic conditions seemed to play a minimal role in the amount of As released. Dissolved species analysis showed us that 100% of the As was As(V), Our ICP-MS results vary due to the heterogeneity of samples, but when high levels are Fe are seen in solution, we also see high levels of As. We also see higher As concentrations when there is a smaller amount of Mn in solution.

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.

The Importance of Water for Life

NASA Astrophysics Data System (ADS)

Westall, Frances; Brack, André

2018-03-01

Liquid water is essential for life as we know it, i.e. carbon-based life. Although other compound-solvent pairs that could exist in very specific physical environments could be envisaged, the elements essential to carbon and water-based life are among the most common in the universe. Carbon molecules and liquid water have physical and chemical properties that make them optimised compound-solvent pairs. Liquid water is essential for important prebiotic reactions. But equally important for the emergence of life is the contact of carbon molecules in liquid water with hot rocks and minerals. We here review the environmental conditions of the early Earth, as soon as it had liquid water at its surface and was habitable. Basing our approach to life as a "cosmic phenomenon" (de Duve 1995), i.e. a chemical continuum, we briefly address the various hypotheses for the origin of life, noting their relevance with respect to early environmental conditions. It appears that hydrothermal environments were important in this respect. We continue with the record of early life noting that, by 3.5 Ga, when the sedimentary environment started being well-preserved, anaerobic life forms had colonised all habitable microenvironments from the sea floor to exposed beach environments and, possibly, in the photic planktonic zone of the sea. Life on Earth had also evolved to the relatively sophisticated stage of anoxygenic photosynthesis. We conclude with an evaluation of the potential for habitability and colonisation of other planets and satellites in the Solar System, noting that the most common life forms in the Solar System and probably in the Universe would be similar to terrestrial chemotrophs whose carbon source is either reduced carbon or CO2 dissolved in water and whose energy would be sourced from oxidized carbon, H2, or other transition elements.

A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site

NASA Astrophysics Data System (ADS)

Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

2013-10-01

The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50 years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in 13C (<-60‰) suggesting production lines which have used depleted methane for synthesis. The other source had typical carbon isotope compositions of >-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, 13C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas.

A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site.

PubMed

Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

2013-10-01

The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in ¹³C (<-60‰) suggesting production lines which have used depleted methane for synthesis. The other source had typical carbon isotope compositions of >-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, ¹³C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas. © 2013 Elsevier B.V. All rights reserved.

Feasibility study of algae-based CO2 capture

EPA Science Inventory

Abstract: The biomass of microalgae contains approximately 50% carbon, which is commonly obtained from the atmosphere, but can also be taken from commercial sources that produce CO2, such as coal-fired power plants. A study of operational demonstration projects is being underta...

Material Transport in ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Rohde, V.; Dux, R.; Mayer, M.; Neu, R.; PA~ 1/4 tterich, T.; Schneider, W.; ASDEX Upgrade-Team,

Today carbon is the most common first wall material in fusion experiments, whereas the first wall of the next step device will consist of a mixture of elements. Especially tungsten has been shown to be an alternative to low-Z materials. However, even with 40% of tungsten coated plasma facing components, carbon is still the dominant impurity at ASDEX Upgrade. A consistent picture of the carbon migration in ASDEX Upgrade has been achieved. Primary carbon sources are the protection limiters at the low field side of the main chamber. Eroded carbon is distributed all over the main chamber. So, the initially tungsten coated central column acts as the main carbon source during discharges, even though a considerable amount of tungsten surfaces persists. Carbon coverage of the central column can significantly change on a shot to shot basis. The divertor target plates act as a strong carbon sink. Deposits are found at the inner and outer divertor, which may be re-eroded forming precursors for layer production at remote areas. In ASDEX Upgrade, deposits on the subdivertor structure are formed by hydro-carbons with a high effective sticking coefficient. A parasitic plasma at these locations may enhance the surface loss probability by surface activation. At more remote areas, such as the pump ducts, a very small deposition is found. Non sticking hydro-carbons are effectively pumped by the cryopump and turbo molecular pumps.

Multiple Phosphatases Regulate Carbon Source-Dependent Germination and Primary Metabolism in Aspergillus nidulans

PubMed Central

de Assis, Leandro José; Ries, Laure Nicolas Annick; Savoldi, Marcela; Dinamarco, Taisa Magnani; Goldman, Gustavo Henrique; Brown, Neil Andrew

2015-01-01

Aspergillus nidulans is an important mold and a model system for the study of fungal cell biology. In addition, invasive A. nidulans pulmonary infections are common in humans with chronic granulomatous disease. The morphological and biochemical transition from dormant conidia into active, growing, filamentous hyphae requires the coordination of numerous biosynthetic, developmental, and metabolic processes. The present study exhibited the diversity of roles performed by seven phosphatases in regulating cell cycle, development, and metabolism in response to glucose and alternative carbon sources. The identified phosphatases highlighted the importance of several signaling pathways regulating filamentous growth, the action of the pyruvate dehydrogenase complex as a metabolic switch controlling carbon usage, and the identification of the key function performed by the α-ketoglutarate dehydrogenase during germination. These novel insights into the fundamental roles of numerous phosphatases in germination and carbon sensing have provided new avenues of research into the identification of inhibitors of fungal germination, with implications for the food, feed, and pharmaceutical industries. PMID:25762568

Use of pulse co-oximetry as a screening and monitoring tool in mass carbon monoxide poisoning.

PubMed

Bledsoe, Bryan E; Nowicki, Kevin; Creel, James H; Carrison, Dale; Severance, Harry W

2010-01-01

Carbon monoxide (CO) poisoning remains a common cause of poisoning in the United States. We describe a case where responding fire department personnel encountered a sick employee with a headache at an automotive brake manufacturing plant. Using both atmospheric CO monitoring and pulse CO-oximetry technology, fire department personnel were able to diagnose the cause of the patient's illness and later identify the source of CO in the plant.

Influence of culture media and environmental factors on mycelial growth and sporulation of Lasiodiplodia theobromae (Pat.) Griffon and Maubl.

PubMed

Saha, A; Mandal, P; Dasgupta, S; Saha, D

2008-05-01

Lasiodiplodia theobromae, a common tea (Camellia sinensis) pathogen, usually does not sporulate or sporulates poorly in common media, which makes spore production difficult. In this study the effects of culture media, carbon source, nitrogen source, temperature, pH and light on mycelial growth and sporulation were evaluated. Among several carbon sources tested, glucose and sucrose were found superior for growth. Potassium nitrate supplemented media showed maximum growth amongst the tested inorganic nitrogen sources while peptone produced maximum growth among the tested organic nitrogen sources. Tea root extract supplemented potato dextrose agar medium was found to be the most suitable for mycelial growth and sporulation of L. theobromae. The fungus grow at temperatures ranging from 40 to 36 degrees C, with optimum growth at 28 degrees C and no growth was noted at 40 degrees C. There was no significant effect of different light period on growth of L. theobromae, but light enhanced sporulation. The fungus grow at pH 3.0-8.0 and optimum growth was observed at pH 6.0. Tea root extract supplemented potato dextrose agar medium with pH 6.0 was the most suitable for production of conidia of L. theobromae at 28 degrees C. Hence this media may be recommended for inoculum production for further studies.

Feasibility study of algae-based CO2 capture

EPA Science Inventory

The biomass of microalgae contains approximately 50% carbon, which is commonly obtained from the atmosphere, but can also be taken from commercial sources that produce CO2, such as coal-fired power plants. A study of operational demonstration projects is being undertaken to eval...

A common bacterial metabolite elicits prion-based bypass of glucose repression

PubMed Central

Garcia, David M; Dietrich, David; Clardy, Jon; Jarosz, Daniel F

2016-01-01

Robust preference for fermentative glucose metabolism has motivated domestication of the budding yeast Saccharomyces cerevisiae. This program can be circumvented by a protein-based genetic element, the [GAR+] prion, permitting simultaneous metabolism of glucose and other carbon sources. Diverse bacteria can elicit yeast cells to acquire [GAR+], although the molecular details of this interaction remain unknown. Here we identify the common bacterial metabolite lactic acid as a strong [GAR+] inducer. Transient exposure to lactic acid caused yeast cells to heritably circumvent glucose repression. This trait had the defining genetic properties of [GAR+], and did not require utilization of lactic acid as a carbon source. Lactic acid also induced [GAR+]-like epigenetic states in fungi that diverged from S. cerevisiae ~200 million years ago, and in which glucose repression evolved independently. To our knowledge, this is the first study to uncover a bacterial metabolite with the capacity to potently induce a prion. DOI: http://dx.doi.org/10.7554/eLife.17978.001 PMID:27906649

Carbon stocks and carbon fluxes from a 10 year prescribed burning chronosequence on a UK blanket peat.

NASA Astrophysics Data System (ADS)

Clay, G. D.; Worrall, F.

2012-04-01

Prescribed burning is a common land management technique in many areas of the UK uplands. However, concern has been expressed at the impact of this management practice on carbon stocks and fluxes found in the carbon rich peat soils that underlie many of these areas. Existing data shows a range of results at differing spatial and temporal scales for a range of carbon pathways e.g. dissolved organic carbon (DOC), yet there are limited studies that monitor a suite of parameters under burning management. This study measured both carbon stocks and carbon fluxes from a chronosequence of prescribed burn sites in northern England. A range of carbon parameters were measured including: above-ground biomass and carbon stocks; net ecosystem exchange (NEE); ecosystem respiration (Reco); photosynthesis (Pg); and particulate organic carbon (POC). CO2 data was analysed using ANOVA to investigate any significant differences between burn years. Carbon budgets were also calculated using measured and modelled data. Analysis of the CO2 data showed that burning was a significant factor in measured CO2 readings but that other factors such as month of sampling explained a greater proportion of the variation in the data. Carbon budget results show that whilst all the sites were net sources of carbon, the most recent burns were smaller sources of carbon compared to the older burns (Burn year 2009: 85 ± 29 gC/m2/yr; Burn year 1999: 152 ± 12 gC/m2/yr). Additionally, the most recent burns were net sinks of gaseous CO2.

An overview of carbon monoxide generation and release by home appliances

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

Batey, J

Carbon monoxide (CO) is an odorless, colorless and tasteless gas which is highly toxic and can be produced by many combustion sources commonly found within homes. Potential sources include boilers and furnaces, water heaters, space heaters, stoves, ovens, clothes dryers, wood stoves, fireplaces, charcoal grilles, automobiles, cigarettes, oil lamps, and candles. Any fuel that contains carbon can form CO including, natural gas, propane, kerosene, fuel oil, wood, and coal. Exposure to elevated CO levels typically requires its production by a combustion source and its release into the home through a venting system malfunction. The health effects of CO range frommore » headaches and flue-like symptoms to loss of concentration, coma and death depending on the concentration of CO and the exposure time. At levels of only 1%, which is the order of magnitude produced by automobile exhaust, carbon monoxide can cause death in less than 3 minutes. While most combustion equipment operate with low CO levels, many operating factors can contribute to elevated CO levels in the home including: burner adjustment, combustion air supply, house air-tightness, exhaust fan operation, cracked heat exchangers, vent blockages, and flue pipe damage. Test data on CO emissions is presented from a wide range of sources including Brookhaven National Laboratory, Gas Research Institute, American Gas Association, the US Environmental Protection Agency, and the US Consumer Product Safety Commission for many potential CO sources in and near the home.« less

Whole Watershed Quantification of Net Carbon Fluxes by Erosion and Deposition within the Christina River Basin Critical Zone Observatory

NASA Astrophysics Data System (ADS)

Aufdenkampe, A. K.; Karwan, D. L.; Aalto, R. E.; Marquard, J.; Yoo, K.; Wenell, B.; Chen, C.

2013-12-01

We have proposed that the rate at which fresh, carbon-free minerals are delivered to and mix with fresh organic matter determines the rate of carbon preservation at a watershed scale (Aufdenkampe et al. 2011). Although many studies have examined the role of erosion in carbon balances, none consider that fresh carbon and fresh minerals interact. We believe that this mechanism may be a dominant sequestration process in watersheds with strong anthropogenic impacts. Our hypothesis - that the rate of mixing fresh carbon with fresh, carbon-free minerals is a primary control on watershed-scale carbon sequestration - is central to our Christina River Basin Critical Zone Observatory project (CRB-CZO, http://www.udel.edu/czo/). The Christina River Basin spans 1440 km2 from piedmont to Atlantic coastal plain physiographic provinces in the states of Pennsylvania and Delaware, and experienced intensive deforestation and land use beginning in the colonial period of the USA. Here we present a synthesis of multi-disciplinary data from the CRB-CZO on materials as they are transported from sapprolite to topsoils to colluvium to suspended solids to floodplains, wetlands and eventually to the Delaware Bay estuary. At the heart of our analysis is a spatially-integrated, flux-weighted comparison of the organic carbon to mineral surface area ratio (OC/SA) of erosion source materials versus transported and deposited materials. Because source end-members - such as forest topsoils, farmed topsoils, gullied subsoils and stream banks - represent a wide distribution of initial, pre-erosion OC/SA, we quantify source contributions using geochemical sediment fingerprinting approaches (Walling 2005). Analytes used for sediment fingerprinting include: total mineral elemental composition (including rare earth elements), fallout radioisotope activity for common erosion tracers (beryllium-7, beryllium-10, lead-210, cesium-137), particle size distribution and mineral specific surface area, in addition to organic carbon and nitrogen content with stable isotope (13C, 15N) and radiocarbon (14C) abundance to quantify OC/SA and organic carbon sources and mean age. We then use multivariate mixing model analysis to quantify the fractional contribution of each source end-member to each sample of suspended or deposited sediments. Last, we calculate a predicted OC/SA based on source end-member mixing and compare to the measured OC/SA to quantify net change in mineral complexed carbon. Aufdenkampe, A.K. et al. Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere. Frontiers Ecol. Environ. 9, 53-60 (2011). Walling, D. E. Tracing suspended sediment sources in catchments and river systems. Sci. Total Environ. 34, 159-184 (2005).

Carbonate concretions as a significant component of ancient marine carbon cycles: Insights from paired organic and inorganic carbon isotope analyses of a Cretaceous shale

NASA Astrophysics Data System (ADS)

Loyd, S. J.

2014-12-01

Carbonate concretions often occur within fine-grained, organic-rich sedimentary rocks. This association reflects the common production of diagenetic minerals through biologic cycling of organic matter. Chemical analysis of carbonate concretions provides the rare opportunity to explore ancient shallow diagenetic environments, which are inherently transient due to progressive burial but are an integral component of the marine carbon cycle. The late Cretaceous Holz Shale (~80 Ma) contains abundant calcite concretions that exhibit textural and geochemical characteristics indicative of relatively shallow formation (i.e., near the sediment-water interface). Sampled concretions contain between 5.4 and 9.8 wt.% total inorganic carbon (TIC), or ~45 and 82 wt.% CaCO3, compared to host shale values which average ~1.5 wt.% TIC. Organic carbon isotope compositions (δ13Corg) are relatively constant in host and concretion samples ranging from ­-26.3 to -24.0‰ (VPDB). Carbonate carbon isotope compositions (δ13Ccarb) range from -22.5 to -3.4‰, indicating a significant but not entirely organic source of carbon. Concretions of the lower Holz Shale exhibit considerably elevated δ13Ccarb values averaging -4.8‰, whereas upper Holz Shale concretions express an average δ13Ccarb value of -17.0‰. If the remaining carbonate for lower Holz Shale concretions is sourced from marine fluids and/or dissolved marine carbonate minerals (e.g., shells), a simple mass balance indicates that ~28% of concretion carbon was sourced from organic matter and ~72% from late Cretaceous marine inorganic carbon (with δ13C ~ +2.5‰). Upper Holz Shale calculations indicate a ~73% contribution from organic matter and a ~27% contribution from inorganic carbon. When normalized for carbonate, organic contents within the concretions are ~2-13 wt.% enriched compared to host contents. This potentially reflects the protective nature of cementation that acts to limit permeability and chemical destruction of organic material. These data imply that concretion growth in shallow sediments can act as a significant and long-term sink for both marine inorganic and organic carbon.

Effect of dissolved oxygen on biological denitrification using biodegradable plastic as the carbon source

NASA Astrophysics Data System (ADS)

Zhang, Xucai; Zhang, Jianmei

2018-02-01

Biological denitrification is currently a common approach to remove nitrate from wastewater. This study was conducted to evaluate the influence of dissolved oxygen on denitrification in wastewater treatment using biodegradable plastic as carbon source by designing the aerated, anoxic, and low-oxygen experimental treatment groups. The results showed that the removal rates of nitrate in anoxic and low-oxygen groups were 30.6 g NO3 --Nm-3 d-1 and 30.8 g NO3 --N m-3 d-1 at 83 h, respectively, both of which were higher than that of the aerated group. There was no significant difference between the anoxic and low-oxygen treatment groups for the nitrate removal. Additional, the nitrite accumulated during the experiments, and the nitrite concentrations in anoxic and aerated groups were lower than those in low-oxygen group. No nitrite was detected in all groups at the end of the experiments. These findings indicated that dissolved oxygen has important influence on denitrification, and anoxic and low-oxygen conditions can support completely denitrification when using BP as carbon source in nitrate-polluted wastewater treatment.

Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica)

NASA Astrophysics Data System (ADS)

Wukovits, Julia; Enge, Annekatrin Julie; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

2017-06-01

Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus. These conditions are likely to impact nutrient fluxes in A. tepida/H. germanica associations.

Effects of 18 pharmaceuticals on the physiological diversity of edaphic microorganisms.

PubMed

Pino-Otín, Mª Rosa; Muñiz, Selene; Val, Jonatan; Navarro, Enrique

2017-10-01

Pharmaceutical residues can enter the terrestrial environment through the application of recycled water and contaminated biosolids to agricultural soils, were edaphic microfauna can would be threatened. This study thus assessed the effect of 18 widely consumed pharmaceuticals, belonging to four groups: antibiotics, non-steroidal anti-inflammatory drugs (NSAIDs), blood lipid-lowering agents (BLLA) and β-blockers, on the physiology of soil microbial communities from a ecological crop field. Biolog EcoPlates, containing 31 of the most common carbon sources found in forest and crop soils, were used to calculate both the averaged well colour development (AWCD), as an indicator of the entire capacity of degrading carbon sources, and the diversity of carbon source utilization, as an indicator of the physiological diversity. The results show that pharmaceuticals impact microbial communities by changing the ability of microbes to metabolize different carbon sources, thus affecting the metabolic diversity of the soil community. The toxicity of the pharmaceuticals was inversely related to the log K ow ; indeed, NSAIDs were the least toxic and antibiotics were the most toxic, while BLLA and β-blockers presented intermediate toxicity. The antibiotic sulfamethoxazole imposed the greatest impact on microbial communities at concentrations from 100 mg/L, followed by the other two antibiotics (trimethoprim and tetracycline) and the β-blocker nadolol. Other chemical parameters (i.e. melting point, molecular weight, pK a or solubility) had little influence on toxicity. Microbial communities exposed to pharmaceuticals having similar physicochemical characteristics presented similar physiological diversity patterns of carbon substrate utilization. These results suggest that the repeated amendment of agricultural soils with biosolids or sludges containing pharmaceutical residuals may result in soil concentrations of concern regarding key ecological functions (i.e. the carbon cycle). Copyright © 2017 Elsevier B.V. All rights reserved.

Review on heavy ion radiotherapy facilities and related ion sources (invited)a)

NASA Astrophysics Data System (ADS)

Kitagawa, A.; Fujita, T.; Muramatsu, M.; Biri, S.; Drentje, A. G.

2010-02-01

Heavy ion radiotherapy awakens worldwide interest recently. The clinical results obtained by the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan have clearly demonstrated the advantages of carbon ion radiotherapy. Presently, there are four facilities for heavy ion radiotherapy in operation, and several new facilities are under construction or being planned. The most common requests for ion sources are a long lifetime and good stability and reproducibility. Sufficient intensity has been achieved by electron cyclotron resonance ion sources at the present facilities.

The effect of activated carbon support surface modification on characteristics of carbon nanospheres prepared by deposition precipitation of Fe-catalyst

NASA Astrophysics Data System (ADS)

Kristianto, H.; Arie, A. A.; Susanti, R. F.; Halim, M.; Lee, J. K.

2016-11-01

In this study the effect of activated carbon support modification to synthesis of CNSs was observed. Modification of activated carbon was done by using nitric acid. The effect of modification was analyzed from its FTIR spectra. The Fe catalysts were deposited on to the support by using urea deposition precipitation method at various initial catalysts concentration. CNSs was synthesized by utilizing cooking palm oil as renewable carbon source, and pyrolized at 700°C for 1 hour under nitrogen atmosphere. The products obtained then analyzed using SEM-EDS, TEM, XRD, and Raman spectroscopy. The modification of activated carbon support had increased the oxygen functional group. This increase resulted on increase of metal catalysts deposited on activated carbon surface. Peak of C (100) was observed, while ID/IG of samples were obtained around 0.9, which is commonly obtained for CNSs. High catalysts loading on modified activated carbon support caused decomposition of CNSs and formation carbon onion.

Source data supported high resolution carbon emissions inventory for urban areas of the Beijing-Tianjin-Hebei region: Spatial patterns, decomposition and policy implications.

PubMed

Cai, Bofeng; Li, Wanxin; Dhakal, Shobhakar; Wang, Jianghao

2018-01-15

This paper developed internationally compatible methods for delineating boundaries of urban areas in China. By integrating emission source data with existing official statistics as well as using rescaling methodology of data mapping for 1 km grid, the authors constructed high resolution emission gridded data in Beijing-Tianjin-Hebei (Jing-Jin-Ji) region in China for 2012. Comparisons between urban and non-urban areas of carbon emissions from industry, agriculture, household and transport exhibited regional disparities as well as sectoral differences. Except for the Hebei province, per capita total direct carbon emissions from urban extents in Beijing and Tianjin were both lower than provincial averages, indicating the climate benefit of urbanization, comparable to results from developed countries. Urban extents in the Hebei province were mainly industrial centers while those in Beijing and Tianjin were more service oriented. Further decomposition analysis revealed population to be a common major driver for increased carbon emissions but climate implications of urban design, economic productivity of land use, and carbon intensity of GDP were both cluster- and sector-specific. This study disapproves the one-size-fits-all solution for carbon mitigation but calls for down-scaled analysis of carbon emissions and formulation of localized carbon reduction strategies in the Jing-Jin-Ji as well as other regions in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbon Monitoring System Applications Framework: Lessons Learned from Stakeholder Engagement Activities

NASA Astrophysics Data System (ADS)

Sepulveda Carlo, E.; Escobar, V. M.; Delgado Arias, S.; Forgotson, C.

2017-12-01

The NASA Carbon Monitoring System initiated by U.S. Congress in 2010 is developing products that characterize and quantify carbon sources and sinks in the United States and the global tropics. In 2013, an applications effort was selected to engage potential end users and gather feedback about their data needs. For the past four years the CMS applications efforts has expanded and implemented a number of strategies to connect carbon scientists to decision-makers, contributing to the societal benefits of CMS data products. The applications efforts use crowd sourcing to collects feedback from stakeholders on challenges and lessons learned in the use of CMS data products. Some of the most common data needs from engaged organizations include above and below-ground biomass and fluxes in forestlands and wetlands, and greenhouse gas (GHG) emissions across all land use/cover and land use changes. Stakeholder organizations' needs for CMS data products support national GHG inventories following the Paris Agreement, carbon markets, and sub-national natural resources management and policies. The lessons learned report presents stakeholder specific applications, challenges, and successes from using CMS data products. To date, the most common uses of CMS products include: conservation efforts, emissions inventory, forestry and land cover applications, and carbon offset projects. The most common challenges include: the need for familiar and consistent products over time, budget constraints, and concern with uncertainty of modeled results. Recurrent recommendations from stakeholder indicate that CMS should provide high resolution (30m) and frequent data products updates (annually). The applications efforts have also helped identified success stories from different CMS projects, including the development of the GHG emissions inventory from Providence, RI, the improvement of the U.S. GHG Inventory though the use of satellite data, and the use of high resolution canopy cover maps for forestry, conservation, and ecosystem services applications in the tristate area of Maryland, Delaware and Pennsylvania. The presentation will discuss the applications framework methodology and strategy, as well as highlight some of the results and lessons learned from these applications efforts.

Dissolved organic carbon in the precipitation of Seoul, Korea: Implications for global wet depositional flux of fossil-fuel derived organic carbon

NASA Astrophysics Data System (ADS)

Yan, Ge; Kim, Guebuem

2012-11-01

Precipitation was sampled in Seoul over a one-year period from 2009 to 2010 to investigate the sources and fluxes of atmospheric dissolved organic carbon (DOC). The concentrations of DOC varied from 15 μM to 780 μM, with a volume-weighted average of 94 μM. On the basis of correlation analysis using the commonly acknowledged tracers, such as vanadium, the combustion of fossil-fuels was recognized to be the dominant source. With the aid of air mass backward trajectory analyses, we concluded that the primary fraction of DOC in our precipitation samples originated locally in Korea, albeit the frequent long-range transport from eastern and northeastern China might contribute substantially. In light of the relatively invariant organic carbon to sulfur mass ratios in precipitation over Seoul and other urban regions around the world, the global magnitude of wet depositional DOC originating from fossil-fuels was calculated to be 36 ± 10 Tg C yr-1. Our study further underscores the potentially significant environmental impacts that might be brought about by this anthropogenically derived component of organic carbon in the atmosphere.

Suitability of biogenic carbonate of Lithospermum fruits for 14C dating

NASA Astrophysics Data System (ADS)

Pustovoytov, Konstantin; Riehl, Simone

2006-05-01

Lithospermum (Boraginaceae) belongs to a small group of plant taxa that accumulate biogenic carbonate in their fruits. In this genus, carbonate incrustations form in the cells of the epidermis and sclerenchyma of the pericarp. Fossil Lithospermum fruits (nutlets) with well-preserved calcified tissues commonly occur in Quaternary sediments and cultural layers. We tested the suitability of biogenic carbonate of Lithospermum fruits for radiocarbon dating using a total of 15 AMS measurement results from four modern and 11 fossil samples. The 14C data from modern samples suggest that Lithospermum utilises only atmospheric carbon to synthesise calcite in the nutlets. In general, the ages determined through 14C dating of fossil fruitscorresponded well with the absolute-age intervals for archaeological sites over the last 5000 yr. Biogenic carbonate of Lithospermum fruits, like that of Celtis, represents a new source of chronological information for late Quaternary studies.

Establishing a synergetic carbon utilization mechanism for non-catabolic use of glucose in microbial synthesis of trehalose.

PubMed

Wu, Yifei; Sun, Xinxiao; Lin, Yuheng; Shen, Xiaolin; Yang, Yaping; Jain, Rachit; Yuan, Qipeng; Yan, Yajun

2017-01-01

In nature glucose is a common carbon and energy source for catabolic use and also a building unit of polysaccharides and glycosylated compounds. The presence of strong glucose catabolic pathways in microorganism rapidly decomposes glucose into smaller metabolites and challenges non-catabolic utilization of glucose as C6 building unit or precursor. To address this dilemma, we design a synergetic carbon utilization mechanism (SynCar), in which glucose catabolism is inactivated and a second carbon source (e.g. glycerol) is employed to maintain cell growth and rationally strengthen PEP driving force for glucose uptake and non-catabolic utilization. Remarkably, a trehalose biosynthesis model developed for proof-of-concept indicates that SynCar leads to 131% and 200% improvement in trehalose titer and yield, respectively. The conversion rate of glucose to trehalose reaches 91% of the theoretical maximum. This work demonstrates the broad applicability of SynCar in the biosynthesis of molecules derived from non-catabolic glucose. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Characteristics and carbon stable isotopes of fluids in the Southern Kerala granulites and their bearing on the source of CO2

NASA Technical Reports Server (NTRS)

Santosh, M.; Jackson, D. H.; Mattey, D. P.; Harris, N. B. W.

1988-01-01

Carbon dioxide-rich inclusions commonly occur in the banded charnockites and khondalites of southern Kerala as well as in the incipient charnockites formed by desiccation of gneisses along oriented zones. The combined high density fluid inclusion isochores and the range of thermometric estimates from mineral assemblages indicate entrapment pressures in the range of 5.4 to 6.1 Kbar. The CO2 equation of state barometry closely compares with the 5 plus or minus 1 Kbar estimate from mineral phases for the region. The isochores for the high density fluid inclusions in all the three rock types pass through the P-T domain recorded by phase equilibria, implying that carbon dioxide was the dominating ambient fluid species during peak metamorphic conditions. In order to constrain the source of fluids and to evaluate the mechanism of desiccation, researchers undertook detailed investigations of the carbon stable isotope composition of entrapped fluids. Researchers report here the results of preliminary studies in some of the classic localities in southern Kerala namely, Ponmudi, Kottavattom, Manali and Kadakamon.

Synthesis of carbon nanomaterials from different pyrolysis techniques: a review

NASA Astrophysics Data System (ADS)

Umer Zahid, Muhammad; Pervaiz, Erum; Hussain, Arshad; Shahzad, Muhammad Imran; Niazi, Muhammad Bilal Khan

2018-05-01

In the current age, the significance of carbon-based nanomaterials for many applications has made the efforts for the facile synthesis methods from abundantly available wastes in a cost-effective way. Pyrolysis in a broad spectrum is commonly employed for the synthesis of carbon nanostructures by thermally treating the organic waste. The mechanism of growth of the nanoparticles determines the functional distribution of nanoparticles based on the growing size, medium, and physio-chemical properties. Carbon nanomaterial’s growth is a complicated process which is profoundly influenced by temperature, catalyst, and type of precursor. Nowadays, significant progress has been made in improving nanomaterial’s growth techniques, opening new paths for commercial production of carbon-based nanomaterials. The most promising are the methods involving hydrocarbon-rich organic waste as the feed source. In this review, synthesis of carbon-based nanomaterials, specifically carbon nanotubes (CNTs), Carbon nanofibers (CNFs) and Graphene (G) are discussed by different pyrolysis techniques. Furthermore, the review explores recent advancements made in the context of pyrolysis.

Very large release of mostly volcanic carbon during the Palaeocene-Eocene Thermal Maximum

NASA Astrophysics Data System (ADS)

Gutjahr, Marcus; Ridgwell, Andy; Sexton, Philip F.; Anagnostou, Eleni; Pearson, Paul N.; Pälike, Heiko; Norris, Richard D.; Thomas, Ellen; Foster, Gavin L.

2017-08-01

The Palaeocene-Eocene Thermal Maximum (PETM) was a global warming event that occurred about 56 million years ago, and is commonly thought to have been driven primarily by the destabilization of carbon from surface sedimentary reservoirs such as methane hydrates. However, it remains controversial whether such reservoirs were indeed the source of the carbon that drove the warming. Resolving this issue is key to understanding the proximal cause of the warming, and to quantifying the roles of triggers versus feedbacks. Here we present boron isotope data—a proxy for seawater pH—that show that the ocean surface pH was persistently low during the PETM. We combine our pH data with a paired carbon isotope record in an Earth system model in order to reconstruct the unfolding carbon-cycle dynamics during the event. We find strong evidence for a much larger (more than 10,000 petagrams)—and, on average, isotopically heavier—carbon source than considered previously. This leads us to identify volcanism associated with the North Atlantic Igneous Province, rather than carbon from a surface reservoir, as the main driver of the PETM. This finding implies that climate-driven amplification of organic carbon feedbacks probably played only a minor part in driving the event. However, we find that enhanced burial of organic matter seems to have been important in eventually sequestering the released carbon and accelerating the recovery of the Earth system.

Direct and Dry Deposited Single-Walled Carbon Nanotube Films Doped with MoO(x) as Electron-Blocking Transparent Electrodes for Flexible Organic Solar Cells.

PubMed

Jeon, Il; Cui, Kehang; Chiba, Takaaki; Anisimov, Anton; Nasibulin, Albert G; Kauppinen, Esko I; Maruyama, Shigeo; Matsuo, Yutaka

2015-07-01

Organic solar cells have been regarded as a promising electrical energy source. Transparent and conductive carbon nanotube film offers an alternative to commonly used ITO in photovoltaics with superior flexibility. This communication reports carbon nanotube-based indium-free organic solar cells and their flexible application. Direct and dry deposited carbon nanotube film doped with MoO(x) functions as an electron-blocking transparent electrode, and its performance is enhanced further by overcoating with PSS. The single-walled carbon nanotube organic solar cell in this work shows a power conversion efficiency of 6.04%. This value is 83% of the leading ITO-based device performance (7.48%). Flexible application shows 3.91% efficiency and is capable of withstanding a severe cyclic flex test.

Optimization of Carbon and Nitrogen Sources for Extracellular Polymeric Substances Production by Chryseobacterium indologenes MUT.2.

PubMed

Khani, Mojtaba; Bahrami, Ali; Chegeni, Asma; Ghafari, Mohammad Davoud; Mansouran Zadeh, ALi

2016-06-01

Bacterial Extracellular Polymeric Substances (EPS) are environmental friendly and versatile polymeric materials that are used in a wide range of industries such as: food, textile, cosmetics, and pharmaceuticals. To make the production process of the EPS cost-effective, improvements in the production yield is required which could be implemented through application of processes such as optimized culture conditions, and development of the strains with higher yield ( e.g . through genetic manipulation), or using low-cost substrates. In this work, the effects of carbon and nitrogen sources were studied in order to improve the EPS production by the submerged cultivation of Chryseobacterium indologenes MUT.2. The mesophilic microorganism Chryseobacterium indologenes MUT.2, was grown and maintained in the Luria Bertani agar. The initial basal medium contained: glucose (20 g.L -1 ), yeast extracts (5 g.L -1 ), K 2 HPO 4 (6 g.L -1 ), NaH 2 PO 4 (7 g.L -1 ), NH 4 CL (0.7 g.L -1 ), and MgSO 4 (0.5 g.L -1 ). For evaluating the carbon and nitrogen sources' effect on the fermentation performance, cultures were prepared in 500 mL flasks filled with 300 mL of the medium. The single-factor experiments based on statistics was employed to evaluate and optimize the carbon and nitrogen sources for EPS production in the liquid culture medium of Chryseobacterium indologenes MUT.2. The preferred carbon-sources, sucrose and glucose, commonly gave the highest EPS production of 8.32 and 6.37 g.L -1 , respectively, and the maximum EPS production of 8.87 g.L -1 was achieved when glutamic acid (5 g.L -1 ) was employed as the nitrogen source. In this work, the culture medium for production of EPS by Chryseobacterium indologenes MUT.2 was optimized. Compared to the basal culture medium in shake-flasks and stirred tank bioreactor, the use of optimized culture medium has resulted in a 53% and 73% increase in the EPS production, respectively.

Large area multiarc ion beam source {open_quote}MAIS{close_quote}

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

Engelko, V.; Giese, H.; Schalk, S.

1996-12-31

A pulsed large area intense ion beam source is described, in which the ion emitting plasma is built up by an array of individual discharge units, homogeneously distributed over the surface of a common discharge electrode. A particularly advantageous feature of the source is that for plasma generation and subsequent acceleration of the ions only one common energy supply is necessary. This allows to simplify the source design and provides inherent synchronization of plasma production and ion extraction. The homogeneity of the plasma density was found to be superior to plasma sources using plasma expanders. Originally conceived for the productionmore » of proton beams, the source can easily be modified for the production of beams composed of carbon and metal ions or mixed ion species. Results of investigations of the source performance for the production of a proton beam are presented. The maximum beam current achieved to date is of the order of 100 A, with a particle kinetic energy of 15 - 30 keV and a pulse length in the range of 10 {mu}s.« less

Assessing the Resilience of a Blue Carbon Store: Characterizing the Lateral Flux of DIC from an East Coast U.S. Saltmarsh using Δ14C and δ13C

NASA Astrophysics Data System (ADS)

Felgate, S. L.; Gonneea, M. E.; Kroeger, K. D.; Chu, S. N.; Wang, A. Z.

2016-12-01

Intertidal saltmarshes are highly productive coastal habitats and important blue carbon stores. They commonly exhibit high salinity, low oxygen environmental regimes which lend themselves towards reduced rates of microbial respiration, and the assimilation of atmospheric CO2 into plant biomass tends to outpace the rate at which that biomass is broken down. As a result, a relatively high proportion of CO2 entering the system can be expected to become incorporated into marsh sediment before it can be metabolised, potentially entering storage for thousands of years and providing a sizeable natural carbon sink. However, the rate at which these habitats are now being degraded is substantial and growing: the combined impacts of stressors such as increasing temperature and sea level rise are predicted to reduce global saltmarsh coverage by 30-40% by the end of the century, and many saltmarsh carbon stores can be expected to shift from net sinks to sources within the same time frame. Based on high resolution measurements and modelling in a northeastern U.S. saltmarsh, a recent study reported a marsh DIC export of 414g C m2 yr-1. This is more than twice that put forward in previous estimates, and is larger than the total uptake by plant biomass. This translates into one of the largest carbon fluxes to the coastal ocean found along the U.S. East Coast. Additionally it is possible that the marsh carbon budget is not in balance, with export exceeding carbon fixation rates. Here we characterise this carbon flux using Δ14C and δ13C data to age and source the exported dissolved carbon pools. Carbon isotope mixing models between surface (modern) and porewater (old) carbon sources are constrained by creek samples and porewaters from multiple depths and locations within the marsh. We determine the age of exported carbon to see if carbon stored over the lifetime of the marsh (c. 2000 years) continues to be respired, thereby evaluating the long term resilience of the carbon sink.

Geochemical insights into the lithology of mantle sources for Cenozoic alkali basalts in West Qinling, China

NASA Astrophysics Data System (ADS)

Dai, Li-Qun; Zheng, Fei; Zhao, Zi-Fu; Zheng, Yong-Fei

2018-03-01

Although alkali basalts are common in oceanic islands and continental rifts, the lithology of their mantle sources is still controversial. While the peridotite is usually viewed as a common source lithology, there are increasing studies suggesting significant contributions from ultramafic metasomatites such as carbonated peridotite, pyroxenite and hornblendite to the origin of alkali basalts. The present study indicates that carbonated peridotite plus hornblendite would have served as the mantle sources of Cenozoic alkali basalts from the West Qinling orogen in China. The target basalts show low SiO2 contents of 36.9 to 40.8 wt% and highly variable Na2O + K2O contents from 0.86 to 4.77 wt%, but high CaO contents of 12.5 to 16.3 wt% and CaO/Al2O3 ratios of 1.42 to 2.19. They are highly enriched in the majority of incompatible trace elements, but depleted in Rb, K, Pb, Zr, Hf, and Ti. Furthermore, they exhibit high (La/Yb)N, Zr/Hf, Ce/Pb and Nb/Ta ratios, but low Ti/Eu and Hf/Sm ratios. Generally, with increasing (La/Yb)N and CaO/Al2O3 ratios, their Ti/Eu and Hf/Sm ratios decrease whereas their Zr/Hf, Ce/Pb and Nb/Ta ratios increase. These major and trace element features are similar to those of carbonatites and hornblendite-derived melts to some extent, but significantly different from those of mid-ocean ridge basalts (MORB). This suggests that the alkali basalts would be originated from metasomatic mantle sources. A comparison of the major-trace elements in the alkali basalts with those of some representative mantle-derived melts indicates that the source lithology of alkali basalts is a kind of ultramafic metasomatites that are composed of carbonated peridotite and hornblendite. Such metasomatites would be generated by reaction of the depleted MORB mantle peridotite with hydrous, carbonate-bearing felsic melts derived from partial melting of the subducted Paleotethyan oceanic crust. Therefore, the melt-peridotite reaction at the slab-mantle interface in the Paleotethyan subduction channel plays the key role in transferring the geochemical signatures from the subducted Paleotethyan oceanic crust to the alkali basalts in the fossil convergent plate margin.

Gordonia (nocardia) amarae foaming due to biosurfactant production.

PubMed

Pagilla, K R; Sood, A; Kim, H

2002-01-01

Gordonia amarae, a filamentous actinomycete, commonly found in foaming activated sludge wastewater treatment plants was investigated for its biosurfactant production capability. Soluble acetate and paringly soluble hexadecane were used as carbon sources for G. amarae growth and biosurfactant production in laboratory scale batch reactors. The lowest surface tension (critical micelle concentration, CMC) of the cell-free culture broth was 55 dynes/cm when 1,900 mg/L acetate was used as the sole carbon source. The lowest surface tension was less than 40 dynes/cm when either 1% (v/v) hexadecane or a mixture of 1% (v/v) hexadecane and 0.5% (w/v) acetate was used as the carbon source. The maximum biomass concentration (the stationary phase) was achieved after 4 days when acetate was used along with hexadecane, whereas it took about 8 days to achieve the stationary phase with hexadecane alone. The maximum biosurfactant production was 3 x CMC with hexadecane as the sole carbon source, and it was 5 x CMC with the mixture of hexadecane and acetate. Longer term growth studies (approximately 35 days of culture growth) indicated that G. amarae produces biosurfactant in order to solubilize hexadecane, and that adding acetate improves its biosurfactant production by providing readily degradable substrate for initial biomass growth. This research confirms that the foaming problems in activated sludge containing G. amarae in the activated sludge are due to the biosurfactant production by G. amarae when hydrophobic substrates such as hexadecane are present.

Draft genome sequence of the oleaginous yeast Cryptococcus curvatus ATCC 20509

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

Close, Dan; Ojumu, John O.

Cryptococcus curvatus ATCC 20509 is a commonly used nonmodel oleaginous yeast capable of converting a variety of carbon sources into fatty acids. In addition, we present the draft genome sequence of this popular organism to provide a means for more in-depth studies of its fatty acid production potential.

Draft genome sequence of the oleaginous yeast Cryptococcus curvatus ATCC 20509

DOE PAGES

Close, Dan; Ojumu, John O.

2016-11-03

Cryptococcus curvatus ATCC 20509 is a commonly used nonmodel oleaginous yeast capable of converting a variety of carbon sources into fatty acids. In addition, we present the draft genome sequence of this popular organism to provide a means for more in-depth studies of its fatty acid production potential.

DEGRADATION OF TRICHLOROETHYLENE UNDER HIGH-TEMPERATURE THERMAL SOURCE-ZONE REMOVAL CONDITIONS (ABSTRACT ONLY)

EPA Science Inventory

Trichloroethylene (TCE) is a contaminant commonly found in the subsurface at industrial and military installations in the United States. Oxidation of TCE (C₂HCl₃) to carbon dioxide (CO₂) and chloride ions (Cl^-) has been reported to occu...

DEGRADATION OF TRICHLOROETHYLENE UNDER HIGH-TEMPERATURE THERMAL SOURCE-ZONE REMOVAL CONDITIONS (POSTER PRESENTATION)

EPA Science Inventory

Trichloroethylene (TCE) is a contaminant commonly found in the subsurface at industrial and military installations in the United States. Oxidation of TCE (C₂HCl₃) to carbon dioxide (CO₂) and chloride ions (Cl^-) has been reported to occu...

Can Sediment Total Organic Carbon and Grain Size Be Used to Diagnose Organic Enrichment in Estuaries

EPA Science Inventory

Eutrophication (i.e., nutrient enrichment, organic enrichment and oxygen depletion) is one of the most common sources of impairment in 303(d) listed waters in the United States. While eutrophication can eventually cause adverse effects to the benthos, it may be hard to diagnose....

Evaluating North Sea carbon sources using radiogenic (224Ra and 228Ra) and stable carbon isotope (DI13C) tracers

NASA Astrophysics Data System (ADS)

Burt, William; Thomas, Helmuth; Hagens, Mathilde; Brenner, Heiko; Paetsch, Johannes; Clargo, Nikki

2015-04-01

In the North Sea, much uncertainty still exists regarding the role of boundary fluxes (e.g. benthic input from sediments or lateral inputs from the coastline) in the overall biogeochemical cycling of the system. The stable carbon isotope signature of dissolved inorganic carbon (δ13C-DIC) is a common tool for following transformations of carbon in the water column and identifying carbon sources and sinks. Here, analyses of the first basin-wide observations of δ13C-DIC reveal that a balance between biological production and respiration, as well as a freshwater input near the European continental coast, predominantly control surface distributions in the North Sea. A strong relationship between the biological component of DIC (DICbio) and δ13C-DIC is then used to quantify the metabolic DIC flux associated with changes in the carbon isotopic signature. Correlations are also found between δ13C-DIC and naturally-occurring Radium isotopes (224Ra and 228Ra), which have well-identified sources from the seafloor and coastal boundaries. The relationship between δ13C-DIC and the longer-lived 228Ra isotope (half-life = 5.8 years) is used to derive a metabolic DIC flux from the European continental coastline. 228Ra is also shown to be a highly effective tracer of North Sea total alkalinity (TA) compared to the more conventional use of salinity as a tracer. Coastal alkalinity inputs are calculated using relationships with 228Ra, and ratios of DIC and TA suggest denitrification as the main metabolic pathway for the formation of these coastal inputs. Finally, coastal TA inputs are translated into inputs of protons to quantify their impact on the buffering capacity of the Southern North Sea.

Origin and effect factors of sedimentary organic carbon in a karst groundwater-fed reservoir, South China.

PubMed

Huang, Siyu; Pu, Junbing; Cao, Jianhua; Li, Jianhong; Zhang, Tao; Jiang, Feng; Li, Li; Wu, Feihong; Pan, Moucheng; Bai, Bing

2018-03-01

Reservoirs are commonly recharged by groundwater that is rich in bicarbonate ions in karst regions of South China, and the recharge of this groundwater to the reservoir can affect the biogeochemical processes of carbon sedimentation at the reservoir bottom. In this study, Dalongdong Reservoir, which is mainly recharged by two subterranean streams, was investigated based on a 42-cm-thick sedimentary core and the 210 Pb/ 137 Cs dating technique and isotope analyses to understand the sedimentary history and identify the carbon sources. The 210 Pb/ 137 Cs age model showed that the sediments were accumulated over the last 60 years. The annual increase precipitation and temperature showed no obvious change compared with trends of δ 13 C in total organic carbon (δ 13 C org ), δ 15 N values in total nitrogen, and the carbon and nitrogen ratio (C/N). This shows that climate was not the main control of the variation in sediment factors. Based on δ 13 C org , δ 15 N, C/N, and isotopic mixing modeling, sources of organic carbon in the sediments were derived from plankton (60.84%), soil (22.93%), waste water (14.56%), and terrestrial plants (1.67%). From 1958 to 1978, reservoir establishment and leakage affected the contribution of the four sources. The contribution of the plankton source increased from 1978 to 2015, resulting from change of water level and continued input of external nitrogen. However, because of the revegetation supplied by an economic aid project the contribution of soil showed a considerable decreasing trend from 1978 to 2002. After 2002, For "Grain for Green" project, the contribution from soil further decreased. After reservoir construction, the contribution of waste water stabilized. The contribution of terrestrial plants started increased rapidly after 2002. Karst groundwater, which contains more dissolved inorganic carbon containing lower δ 13 C DIC than the water sources of other lakes or reservoirs, makes the δ 13 C org value of sediment more negative by phytoplankton photosynthesis in the reservoir.

Influence of Three Contrasting Detrital Carbon Sources on Planktonic Bacterial Metabolism in a Mesotrophic Lake.

PubMed

Wehr; Petersen; Findlay

1999-01-01

Abstract Lakes receive organic carbon from a diversity of sources which vary in their contribution to planktonic microbial food webs. We conducted a mesocosm study to test the effects of three different detrital carbon sources (algae, aquatic macrophytes, terrestrial leaves) on several measures of microbial metabolism in a small meso-eutrophic lake (DOC approximately 5 mg/L). Small DOC additions (DeltaC < 1 mg/L) affected bacterial numbers, growth, and pathways of carbon acquisition. Macrophyte and leaf detritus significantly increased TDP and color, but bacterial densities initially (+12 h) were unaffected. After 168 h, densities in systems amended with terrestrial detritus were 60% less than in controls, while production rates in mesocosms with macrophyte detritus were 4-fold greater. Detritus treatments resulted in greater per-cell production rates either through stable cell numbers and greater growth rates (macrophyte-C) or lower densities with stable production rates (terrestrial-C). After only 12 h, rates of leucine aminopeptidase (LAPase) activity were 2.5x greater in macrophyte-C systems than in controls, but LAPase and beta-N-acetylglucosamindase activities in systems amended with terrestrial-C were only 50% of rates in controls. After 168 h, beta-xylosidase rates were significantly greater in communities with terrestrial and phytoplankton detritus. Microbial utilization of >20% of 102 carbon sources tested were affected by at least one detritus addition. Macrophyte-C had positive (6% of substrates) and negative (14%) effects on substrate use; terrestrial detritus had mainly positive effects. An ordination based on carbon-use profiles (+12 h) revealed a cluster of macrophyte-amended communities with greater use of psicose, lactulose, and succinamic acid; controls and algal-detritus systems were more effective in metabolizing two common sugars and cellobiose. After 168 h, communities receiving terrestrial detritus were most tightly clustered, exhibiting greater use of raffinose, pyroglutamic acid, and sebacic acid. Results suggest that pelagic bacterial communities respond to changes in organic carbon source rapidly and by different routes, including shifts in per-cell production rates and variations in degradation of a variety of compounds comprising the DOC pool.

Trihalomethanes in marine mammal aquaria: occurrences, sources, and health risks.

PubMed

Wang, Jun-Jian; Chow, Alex T; Sweeney, Joelle M; Mazet, Jonna A K

2014-08-01

Disinfecting water containing the high levels of dissolved organic carbon (DOC) commonly generated during pinniped husbandry may cause the formation of carcinogenic disinfection byproducts (DBPs). Little information is available on DBP levels, sources, and health risks in marine mammal aquaria. Using the commonly observed trihalomethanes (THMs) as a DBP indicator, we monitored concentrations for seven months at The Marine Mammal Center in Sausalito, California, one of the largest pinniped rehabilitation facilities in the world. Concentrations of THMs ranged 1.1-144.2 μg/L in pool waters and generally increased with number of animals housed (P < 0.05). To identify the sources of THM precursors in marine mammal aquaria, we intensively monitored the mass flows of potential THM precursors (i.e. food and wastes) in an isolated system with nine individual California sea lions to evaluate the sources and reactivity of dissolved organic carbon (DOC) for 2-5 weeks. The common frozen foods used in feeding pinnipeds, including herring, sardine, and squid, produced an average of 22-34 mg-DOC/g-food in water and 836-1066 μg-THM/g-food after chlorination, whereas the fecal materials, including fresh scat, decomposed scat, and urine, produced 2-16 mg-DOC/g-waste and 116-768 μg-THM/g-waste. Food not eaten by animals could cause a sharp increase of DOC and DBP production and therefore should be removed rapidly from pools. Marine mammal husbandry staff and trainers are at risk (5.16 × 10(-4) to 1.30 × 10(-3)) through exposure of THMs, exceeding the negligible risk level (10(-6)) defined by the US Environmental Protection Agency. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular carbon isotopic evidence for the origin of geothermal hydrocarbons

USGS Publications Warehouse

Des Marais, D.J.; Donchin, J.H.; Nehring, N.L.; Truesdell, A.H.

1981-01-01

Previous interest in light hydrocarbons from geothermal systems has focused principally on the origin of the methane1 and the estimation of subsurface temperatures from the carbon isotopic content of coexisting methane and carbon dioxide1-3. Higher molecular weight hydrocarbons were first reported in gases from Yellowstone National Park4, and have since been found to occur commonly in geothermal emanations in the western United States5. Isotopic measurements of individual geothermal hydrocarbons are now reported which help to explain the origin of these hydrocarbons. The thermal decomposition of sedimentary or groundwater organic matter is a principal source of hydrocarbons in four geothermal areas in western North America. ?? 1981 Nature Publishing Group.

A global perspective on the trophic geography of sharks.

PubMed

Bird, Christopher S; Veríssimo, Ana; Magozzi, Sarah; Abrantes, Kátya G; Aguilar, Alex; Al-Reasi, Hassan; Barnett, Adam; Bethea, Dana M; Biais, Gérard; Borrell, Asuncion; Bouchoucha, Marc; Boyle, Mariah; Brooks, Edward J; Brunnschweiler, Juerg; Bustamante, Paco; Carlisle, Aaron; Catarino, Diana; Caut, Stéphane; Cherel, Yves; Chouvelon, Tiphaine; Churchill, Diana; Ciancio, Javier; Claes, Julien; Colaço, Ana; Courtney, Dean L; Cresson, Pierre; Daly, Ryan; de Necker, Leigh; Endo, Tetsuya; Figueiredo, Ivone; Frisch, Ashley J; Hansen, Joan Holst; Heithaus, Michael; Hussey, Nigel E; Iitembu, Johannes; Juanes, Francis; Kinney, Michael J; Kiszka, Jeremy J; Klarian, Sebastian A; Kopp, Dorothée; Leaf, Robert; Li, Yunkai; Lorrain, Anne; Madigan, Daniel J; Maljković, Aleksandra; Malpica-Cruz, Luis; Matich, Philip; Meekan, Mark G; Ménard, Frédéric; Menezes, Gui M; Munroe, Samantha E M; Newman, Michael C; Papastamatiou, Yannis P; Pethybridge, Heidi; Plumlee, Jeffrey D; Polo-Silva, Carlos; Quaeck-Davies, Katie; Raoult, Vincent; Reum, Jonathan; Torres-Rojas, Yassir Eden; Shiffman, David S; Shipley, Oliver N; Speed, Conrad W; Staudinger, Michelle D; Teffer, Amy K; Tilley, Alexander; Valls, Maria; Vaudo, Jeremy J; Wai, Tak-Cheung; Wells, R J David; Wyatt, Alex S J; Yool, Andrew; Trueman, Clive N

2018-02-01

Sharks are a diverse group of mobile predators that forage across varied spatial scales and have the potential to influence food web dynamics. The ecological consequences of recent declines in shark biomass may extend across broader geographic ranges if shark taxa display common behavioural traits. By tracking the original site of photosynthetic fixation of carbon atoms that were ultimately assimilated into muscle tissues of 5,394 sharks from 114 species, we identify globally consistent biogeographic traits in trophic interactions between sharks found in different habitats. We show that populations of shelf-dwelling sharks derive a substantial proportion of their carbon from regional pelagic sources, but contain individuals that forage within additional isotopically diverse local food webs, such as those supported by terrestrial plant sources, benthic production and macrophytes. In contrast, oceanic sharks seem to use carbon derived from between 30° and 50° of latitude. Global-scale compilations of stable isotope data combined with biogeochemical modelling generate hypotheses regarding animal behaviours that can be tested with other methodological approaches.

Genome-Scale Reconstruction and Analysis of the Metabolic Network in the Hyperthermophilic Archaeon Sulfolobus Solfataricus

PubMed Central

Ulas, Thomas; Riemer, S. Alexander; Zaparty, Melanie; Siebers, Bettina; Schomburg, Dietmar

2012-01-01

We describe the reconstruction of a genome-scale metabolic model of the crenarchaeon Sulfolobus solfataricus, a hyperthermoacidophilic microorganism. It grows in terrestrial volcanic hot springs with growth occurring at pH 2–4 (optimum 3.5) and a temperature of 75–80°C (optimum 80°C). The genome of Sulfolobus solfataricus P2 contains 2,992,245 bp on a single circular chromosome and encodes 2,977 proteins and a number of RNAs. The network comprises 718 metabolic and 58 transport/exchange reactions and 705 unique metabolites, based on the annotated genome and available biochemical data. Using the model in conjunction with constraint-based methods, we simulated the metabolic fluxes induced by different environmental and genetic conditions. The predictions were compared to experimental measurements and phenotypes of S. solfataricus. Furthermore, the performance of the network for 35 different carbon sources known for S. solfataricus from the literature was simulated. Comparing the growth on different carbon sources revealed that glycerol is the carbon source with the highest biomass flux per imported carbon atom (75% higher than glucose). Experimental data was also used to fit the model to phenotypic observations. In addition to the commonly known heterotrophic growth of S. solfataricus, the crenarchaeon is also able to grow autotrophically using the hydroxypropionate-hydroxybutyrate cycle for bicarbonate fixation. We integrated this pathway into our model and compared bicarbonate fixation with growth on glucose as sole carbon source. Finally, we tested the robustness of the metabolism with respect to gene deletions using the method of Minimization of Metabolic Adjustment (MOMA), which predicted that 18% of all possible single gene deletions would be lethal for the organism. PMID:22952675

Use of stable isotopes of carbon, nitrogen, and sulfer to identify sources of nitrogen in surface waters in the Lower Susquehanna River basin, Pennsylvania

USGS Publications Warehouse

Cravotta, C.A.

1995-01-01

Stable isotopes of carbon (C), nitrogen (N), and sulfur (S) in nitrogen sources and nearby samples of topsoil, subsoil, runoff water, and stream water were measured to evaluate the feasibility of using isotopic data to identify nitrogen sources in stream water from forested, agricultural, or suburban land-use areas. Chemical and isotopic compositions were measured for six N-source types consisting of rain water, forest-leaf litter, synthetic fertilizer, farm-animal manure, municipal-sewage effluent and sludge, and septic-tank effluent and sludge. Compositions of topsoil, subsoil, runoff water, and stream water were measured to evaluate changes in compositions of transported N-containing materials near the N source. Animal manure, human waste (sewage plus septic), and forest-leaf litter can be distinguished on the basis of C; however, most N-sources can not be distinguished on the basis of N and S, owing to wide ranges of compositions and overlap among different N-source types. Although values of N for soil and runoff-water samples are qualitatively similar to those of the applied N source, values of C and S for runoff-water and stream-water samples appear to reflect the compositions of relatively large reservoirs of the elements in soil organic matter and minerals, respectively, and not the composition of the applied N source. Because of incomplete chemical transfor- mations, the ratio of organic carbon to total nitrogen for particulates in runoff or stream waters generally is lower than that for associated, nearby soils, and isotopic compositions commonly differ between particulate and dissolved fractions in the water.

Carbon dioxide inhalation treatments of neurotic anxiety. An overview.

PubMed

Wolpe, J

1987-03-01

A lucky chance more than 30 years ago revealed the remarkable efficacy of single inhalations of high concentrations of carbon dioxide in eliminating or markedly reducing free-floating anxiety. The reduction of anxiety lasts for days, weeks, or longer--well beyond the persistence of carbon dioxide in the body. The effects are explicable on the hypothesis that free-floating anxiety is anxiety conditioned to continuously present sources of stimulation, such as background noise or the awareness of space or time, and that the anxiety response habit is weakened when the anxiety is inhibited by the competition of responses that carbon dioxide induces. More recently, it has become apparent that inhalations of carbon dioxide, applied in a different manner, are effective in overcoming maladaptive anxiety responses to specific stimuli, e.g., social stimuli. The substance is also proving to be a valuable resource in the treatment of the common variety of panic attacks.

Adaptation of maize source leaf metabolism to stress related disturbances in carbon, nitrogen and phosphorus balance

PubMed Central

2013-01-01

Background Abiotic stress causes disturbances in the cellular homeostasis. Re-adjustment of balance in carbon, nitrogen and phosphorus metabolism therefore plays a central role in stress adaptation. However, it is currently unknown which parts of the primary cell metabolism follow common patterns under different stress conditions and which represent specific responses. Results To address these questions, changes in transcriptome, metabolome and ionome were analyzed in maize source leaves from plants suffering low temperature, low nitrogen (N) and low phosphorus (P) stress. The selection of maize as study object provided data directly from an important crop species and the so far underexplored C4 metabolism. Growth retardation was comparable under all tested stress conditions. The only primary metabolic pathway responding similar to all stresses was nitrate assimilation, which was down-regulated. The largest group of commonly regulated transcripts followed the expression pattern: down under low temperature and low N, but up under low P. Several members of this transcript cluster could be connected to P metabolism and correlated negatively to different phosphate concentration in the leaf tissue. Accumulation of starch under low temperature and low N stress, but decrease in starch levels under low P conditions indicated that only low P treated leaves suffered carbon starvation. Conclusions Maize employs very different strategies to manage N and P metabolism under stress. While nitrate assimilation was regulated depending on demand by growth processes, phosphate concentrations changed depending on availability, thus building up reserves under excess conditions. Carbon and energy metabolism of the C4 maize leaves were particularly sensitive to P starvation. PMID:23822863

Adaptation of maize source leaf metabolism to stress related disturbances in carbon, nitrogen and phosphorus balance.

PubMed

Schlüter, Urte; Colmsee, Christian; Scholz, Uwe; Bräutigam, Andrea; Weber, Andreas P M; Zellerhoff, Nina; Bucher, Marcel; Fahnenstich, Holger; Sonnewald, Uwe

2013-07-03

Abiotic stress causes disturbances in the cellular homeostasis. Re-adjustment of balance in carbon, nitrogen and phosphorus metabolism therefore plays a central role in stress adaptation. However, it is currently unknown which parts of the primary cell metabolism follow common patterns under different stress conditions and which represent specific responses. To address these questions, changes in transcriptome, metabolome and ionome were analyzed in maize source leaves from plants suffering low temperature, low nitrogen (N) and low phosphorus (P) stress. The selection of maize as study object provided data directly from an important crop species and the so far underexplored C4 metabolism. Growth retardation was comparable under all tested stress conditions. The only primary metabolic pathway responding similar to all stresses was nitrate assimilation, which was down-regulated. The largest group of commonly regulated transcripts followed the expression pattern: down under low temperature and low N, but up under low P. Several members of this transcript cluster could be connected to P metabolism and correlated negatively to different phosphate concentration in the leaf tissue. Accumulation of starch under low temperature and low N stress, but decrease in starch levels under low P conditions indicated that only low P treated leaves suffered carbon starvation. Maize employs very different strategies to manage N and P metabolism under stress. While nitrate assimilation was regulated depending on demand by growth processes, phosphate concentrations changed depending on availability, thus building up reserves under excess conditions. Carbon and energy metabolism of the C4 maize leaves were particularly sensitive to P starvation.

An atomic carbon source for high temperature molecular beam epitaxy of graphene.

PubMed

Albar, J D; Summerfield, A; Cheng, T S; Davies, A; Smith, E F; Khlobystov, A N; Mellor, C J; Taniguchi, T; Watanabe, K; Foxon, C T; Eaves, L; Beton, P H; Novikov, S V

2017-07-26

We report the use of a novel atomic carbon source for the molecular beam epitaxy (MBE) of graphene layers on hBN flakes and on sapphire wafers at substrate growth temperatures of ~1400 °C. The source produces a flux of predominantly atomic carbon, which diffuses through the walls of a Joule-heated tantalum tube filled with graphite powder. We demonstrate deposition of carbon on sapphire with carbon deposition rates up to 12 nm/h. Atomic force microscopy measurements reveal the formation of hexagonal moiré patterns when graphene monolayers are grown on hBN flakes. The Raman spectra of the graphene layers grown on hBN and sapphire with the sublimation carbon source and the atomic carbon source are similar, whilst the nature of the carbon aggregates is different - graphitic with the sublimation carbon source and amorphous with the atomic carbon source. At MBE growth temperatures we observe etching of the sapphire wafer surface by the flux from the atomic carbon source, which we have not observed in the MBE growth of graphene with the sublimation carbon source.

Effects of iron and calcium carbonate on the variation and cycling of carbon source in integrated wastewater treatments.

PubMed

Zhimiao, Zhao; Xinshan, Song; Yufeng, Zhao; Yanping, Xiao; Yuhui, Wang; Junfeng, Wang; Denghua, Yan

2017-02-01

Iron and calcium carbonate were added in wastewater treatments as the adjusting agents to improve the contaminant removal performance and regulate the variation of carbon source in integrated treatments. At different temperatures, the addition of the adjusting agents obviously improved the nitrogen and phosphorous removals. TN and TP removals were respectively increased by 29.41% and 23.83% in AC-100 treatment under 1-day HRT. Carbon source from dead algae was supplied as green microbial carbon source and Fe 2+ was supplied as carbon source surrogate. COD concentration was increased to 30mg/L and above, so the problem of the shortage of carbon source was solved. Dead algae and Fe 2+ as carbon source supplement or surrogate played significant role, which was proved by microbial community analysis. According to the denitrification performance in the treatments, dead algae as green microbial carbon source combined with iron and calcium carbonate was the optimal supplement carbon source in wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Using Strontium Isotopes in Arid Agricultural Soils to Determine a Sink or Source of CO2

NASA Astrophysics Data System (ADS)

Ortiz, A. C.; Jin, L.

2014-12-01

Arid and semi-arid regions of the world are predicted to continue to expand through land degradation and prolonged drought events. Agricultural practices in these drylands degrade soils through elevated salinity, sodicity and alkalinity. Indeed, flood irrigation loads salts onto the soils including carbonate minerals in the form of calcite. Alfalfa and Pecan are salt tolerant and commonly grown in the arid El Paso region, but need irrigation using Rio Grande water with little to no contribution from local ground waters. We hypothesize that the irrigation is loading extra Ca and bicarbonate to soils and anthropogenically enhancing the precipitation of carbonates. We intend to monitor soil CO2 efflux after irrigation, characterize soil minerals, and combine them to isotopic data of soil, irrigation, and drainage waters to link the sources of Ca and C, kinetics of calcite precipitation, to irrigation events. This will include strontium isotopic analysis to determine the source of calcium in the agricultural fields, U-disequilibrium isotopes to estimate the carbonate ages, and CO2 efflux to monitor atmosphere-soil exchange. Carbon dioxide emissions are expected to change during flood irrigation when soils are saturated. After irrigation events, evaporative effects increase Ca and dissolved inorganic carbon concentration in soil waters leading to precipitation of calcite and thus elevated CO2efflux. Preliminary measurements in the pecan field show a marginally significant difference in CO2 fluxes before and after irrigation (p=0.07, t-test). Carbon dioxide emissions are lower during moist conditions (0.6 g m-2hr-1 CO2) than those in dry conditions (1.0 g m-2hr-1 CO2). Future C isotope data are needed to identify the source of extra CO2, biogenic or calcite-precipitation related. A water leachable extraction of alfalfa soils shows 87Sr/86Sr ratios ranged from 0.7101 to 0.7103, indicating Rio Grande river as a dominant calcium source. Further Sr isotopic analysis of sequential extractions from both alfalfa soils (for calcite fraction), pore waters, irrigation waters, and drainage waters will allow us to quantitatively evaluate the source of calcium in calcite therefore, defining if anthropogenic sources of calcium lead to enhanced CO2 production in agricultural fields.

On-line Field Measurements of Speciated PM1 Emission Factors from Common South Asian Combustion Sources

NASA Astrophysics Data System (ADS)

DeCarlo, P. F.; Goetz, J. D.; Giordano, M.; Stockwell, C.; Maharjan, R.; Adhikari, S.; Bhave, P.; Praveen, P. S.; Panday, A. K.; Jayarathne, T. S.; Stone, E. A.; Yokelson, R. J.

2017-12-01

Characterization of aerosol emissions from prevalent but under sampled combustion sources in South Asia was performed as part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) in April 2015. Targeted emission sources included cooking stoves with a variety of solid fuels, brick kilns, garbage burning, crop-residue burning, diesel irrigation pumps, and motorcycles. Real-time measurements of submicron non-refractory particulate mass concentration and composition were obtained using an Aerodyne mini Aerosol Mass Spectrometer (mAMS). Speciated PM1 mass emission factors were calculated for all particulate species (e.g. organics, sulfates, nitrates, chlorides, ammonium) and for each source type using the carbon mass balance approach. Size resolved emission factors were also acquired using a novel high duty cycle particle time-of-flight technique (ePTOF). Black carbon and brown carbon absorption emission factors and absorption Angström exponents were measured using filter loading and scattering corrected attenuation at 370 nm and 880 nm with a dual spot aethalometer (Magee Scientific AE-33). The results indicate that open garbage burning is a strong emitter of organic aerosol, black carbon, and internally mixed particle phase hydrogen chloride (HCl). Emissions of HCl were attributed to the presence chlorinated plastics. The primarily coal fired brick kilns were found to be large emitters of sulfate but large differences in the organic and light absorbing component of emissions were observed between the two kiln types investigated (technologically advanced vs. traditional). These results, among others, bring on-line and field-tested aerosol emission measurements to an area of atmoshperic research dominated by off-line or laboratory based measurements.

The production of cyanobacterial carbon under nitrogen-limited cultivation and its potential for nitrate removal.

PubMed

Huang, Yingying; Li, Panpan; Chen, Guiqin; Peng, Lin; Chen, Xuechu

2018-01-01

Harmful cyanobacterial blooms (CyanoHABs) represent a serious threat to aquatic ecosystems. A beneficial use for these harmful microorganisms would be a promising resolution of this urgent issue. This study applied a simple method, nitrogen limitation, to cultivate cyanobacteria aimed at producing cyanobacterial carbon for denitrification. Under nitrogen-limited conditions, the common cyanobacterium, Microcystis, efficiently used nitrate, and had a higher intracellular C/N ratio. More importantly, organic carbons easily leached from its dry powder; these leachates were biodegradable and contained a larger amount of dissolved organic carbon (DOC) and carbohydrates, but a smaller amount of dissolved total nitrogen (DTN) and proteins. When applied to an anoxic system with a sediment-water interface, a significant increase of the specific NO X - -N removal rate was observed that was 14.2 times greater than that of the control. This study first suggests that nitrogen-limited cultivation is an efficient way to induce organic and carbohydrate accumulation in cyanobacteria, as well as a high C/N ratio, and that these cyanobacteria can act as a promising carbon source for denitrification. The results indicate that application as a carbon source is not only a new way to utilize cyanobacteria, but it also contributes to nitrogen removal in aquatic ecosystems, further limiting the proliferation of CyanoHABs. Copyright © 2017. Published by Elsevier Ltd.

Primary metabolism in Lactobacillus sakei food isolates by proteomic analysis

PubMed Central

2010-01-01

Background Lactobacillus sakei is an important food-associated lactic acid bacterium commonly used as starter culture for industrial meat fermentation, and with great potential as a biopreservative in meat and fish products. Understanding the metabolic mechanisms underlying the growth performance of a strain to be used for food fermentations is important for obtaining high-quality and safe products. Proteomic analysis was used to study the primary metabolism in ten food isolates after growth on glucose and ribose, the main sugars available for L. sakei in meat and fish. Results Proteins, the expression of which varied depending on the carbon source were identified, such as a ribokinase and a D-ribose pyranase directly involved in ribose catabolism, and enzymes involved in the phosphoketolase and glycolytic pathways. Expression of enzymes involved in pyruvate and glycerol/glycerolipid metabolism were also affected by the change of carbon source. Interestingly, a commercial starter culture and a protective culture strain down-regulated the glycolytic pathway more efficiently than the rest of the strains when grown on ribose. The overall two-dimensional gel electrophoresis (2-DE) protein expression pattern was similar for the different strains, though distinct differences were seen between the two subspecies (sakei and carnosus), and a variation of about 20% in the number of spots in the 2-DE gels was observed between strains. A strain isolated from fermented fish showed a higher expression of stress related proteins growing on both carbon sources. Conclusions It is obvious from the data obtained in this study that the proteomic approach efficiently identifies differentially expressed proteins caused by the change of carbon source. Despite the basic similarity in the strains metabolic routes when they ferment glucose and ribose, there were also interesting differences. From the application point of view, an understanding of regulatory mechanisms, actions of catabolic enzymes and proteins, and preference of carbon source is of great importance. PMID:20412581

Primary metabolism in Lactobacillus sakei food isolates by proteomic analysis.

PubMed

McLeod, Anette; Zagorec, Monique; Champomier-Vergès, Marie-Christine; Naterstad, Kristine; Axelsson, Lars

2010-04-22

Lactobacillus sakei is an important food-associated lactic acid bacterium commonly used as starter culture for industrial meat fermentation, and with great potential as a biopreservative in meat and fish products. Understanding the metabolic mechanisms underlying the growth performance of a strain to be used for food fermentations is important for obtaining high-quality and safe products. Proteomic analysis was used to study the primary metabolism in ten food isolates after growth on glucose and ribose, the main sugars available for L. sakei in meat and fish. Proteins, the expression of which varied depending on the carbon source were identified, such as a ribokinase and a D-ribose pyranase directly involved in ribose catabolism, and enzymes involved in the phosphoketolase and glycolytic pathways. Expression of enzymes involved in pyruvate and glycerol/glycerolipid metabolism were also affected by the change of carbon source. Interestingly, a commercial starter culture and a protective culture strain down-regulated the glycolytic pathway more efficiently than the rest of the strains when grown on ribose. The overall two-dimensional gel electrophoresis (2-DE) protein expression pattern was similar for the different strains, though distinct differences were seen between the two subspecies (sakei and carnosus), and a variation of about 20% in the number of spots in the 2-DE gels was observed between strains. A strain isolated from fermented fish showed a higher expression of stress related proteins growing on both carbon sources. It is obvious from the data obtained in this study that the proteomic approach efficiently identifies differentially expressed proteins caused by the change of carbon source. Despite the basic similarity in the strains metabolic routes when they ferment glucose and ribose, there were also interesting differences. From the application point of view, an understanding of regulatory mechanisms, actions of catabolic enzymes and proteins, and preference of carbon source is of great importance.

Plant Wax n-Alkane and n-Alkanoic Acid Signatures Overprinted by Microbial Contributions and Old Carbon in Meromictic Lake Sediments

NASA Astrophysics Data System (ADS)

Makou, Matthew; Eglinton, Timothy; McIntyre, Cameron; Montluçon, Daniel; Antheaume, Ingrid; Grossi, Vincent

2018-01-01

Specific n-alkanes and n-alkanoic acids are commonly used as biomarkers in paleoenvironmental reconstruction, yet any individual homologue may originate from multiple biological sources. Here we improve source and age controls for these compounds in meromictic systems by measuring the radiocarbon (14C) ages of specific homologues preserved in twentieth century Lake Pavin (France) sediments. In contrast to many studies, 14C ages generally decreased with increasing carbon chain length, from 7.3 to 2.6 ka for the C14-C30 n-alkanoic acids and from 9.2 to 0.3 ka for the C21-C33 n-alkanes. Given a known hard water effect, these values suggest that aquatic microbial sources predominate and contributed to most of the homologues measured. Only the longest chain n-alkanes exclusively represent inputs of higher plant waxes, which were previously sequestered in soils over centennial to millennial timescales prior to transport and deposition. These findings suggest that biomarker source and age should be carefully established for lacustrine settings.

Proteome Analyses of Hydrogen-producing Hyperthermophilic Archaeon Thermococcus onnurineus NA1 in Different One-carbon Substrate Culture Conditions*

PubMed Central

Moon, Yoon-Jung; Kwon, Joseph; Yun, Sung-Ho; Lim, Hye Li; Kim, Min-Sik; Kang, Sung Gyun; Lee, Jung-Hyun; Choi, Jong-Soon; Kim, Seung Il; Chung, Young-Ho

2012-01-01

Thermococcus onnurineus NA1, a sulfur-reducing hyperthermophilic archaeon, is capable of H2-producing growth, considered to be hydrogenogenic carboxydotrophy. Utilization of formate as a sole energy source has been well studied in T. onnurineus NA1. However, whether formate can be used as its carbon source remains unknown. To obtain a global view of the metabolic characteristics of H2-producing growth, a quantitative proteome analysis of T. onnurineus NA1 grown on formate, CO, and starch was performed by combining one-dimensional SDS-PAGE with nano UPLC-MSE. A total of 587 proteins corresponding to 29.7% of the encoding genes were identified, and the major metabolic pathways (especially energy metabolism) were characterized at the protein level. Expression of glycolytic enzymes was common but more highly induced in starch-grown cells. In contrast, enzymes involved in key steps of the gluconeogenesis and pentose phosphate pathways were strongly up-regulated in formate-grown cells, suggesting that formate could be utilized as a carbon source by T. onnurineus NA1. In accordance with the genomic analysis, comprehensive proteomic analysis also revealed a number of hydrogenase clusters apparently associated with formate metabolism. On the other hand, CODH and CO-induced hydrogenases belonging to the Hyg4-II cluster, as well as sulfhydrogenase-I and Mbx, were prominently expressed during CO culture. Our data suggest that CO can be utilized as a sole energy source for H2 production via an electron transport mechanism and that CO2 produced from catabolism or CO oxidation by CODH and CO-induced hydrogenases may subsequently be assimilated into the organic carbon. Overall, proteomic comparison of formate- and CO-grown cells with starch-grown cells revealed that a single carbon compound, such as formate and CO, can be utilized as an efficient substrate to provide cellular carbon and/or energy by T. onnurineus NA1. PMID:22232491

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 gas hydrate-bearing areas can provide insight into long-term seepage dynamics and the genesis and fate of marine gas hydrate reservoirs.

Carbon isotope signature of dissolved inorganic carbon (DIC) in precipitation and atmospheric CO2.

PubMed

Górka, Maciej; Sauer, Peter E; Lewicka-Szczebak, Dominika; Jędrysek, Mariusz-Orion

2011-01-01

This paper describes results of chemical and isotopic analysis of inorganic carbon species in the atmosphere and precipitation for the calendar year 2008 in Wrocław (SW Poland). Atmospheric air samples (collected weekly) and rainwater samples (collected after rain episodes) were analysed for CO2 and dissolved inorganic carbon (DIC) concentrations and for δ13C composition. The values obtained varied in the ranges: atmospheric CO2: 337-448 ppm; δ13CCO2 from -14.4 to -8.4‰; DIC in precipitation: 0.6-5.5 mg dm(-3); δ13CDIC from -22.2 to +0.2‰. No statistical correlation was observed between the concentration and δ13C value of atmospheric CO2 and DIC in precipitation. These observations contradict the commonly held assumption that atmospheric CO2 controls the DIC in precipitation. We infer that DIC is generated in ambient air temperatures, but from other sources than the measured atmospheric CO2. The calculated isotopic composition of a hypothetical CO2 source for DIC forming ranges from -31.4 to -11.0‰, showing significant seasonal variations accordingly to changing anthropogenic impact and atmospheric mixing processes. Copyright © 2010 Elsevier Ltd. All rights reserved.

FT-Raman spectroscopic study of calcium-rich and magnesium-rich carbonate minerals.

PubMed

Edwards, Howell G M; Villar, Susana E Jorge; Jehlicka, Jan; Munshi, Tasnim

2005-08-01

Calcium and magnesium carbonates are important minerals found in sedimentary environments. Although sandstones are the most common rock colonized by endolith organisms, the production of calcium and magnesium carbonates is important in survival strategies of organisms and as a source for the removal of oxalate ions. Extremophile organisms in some situations may convert or destroy carbonates of calcium and magnesium, which gives important information about the conditions under which these organisms can survive. The identification on the surface of Mars of 'White Rock' formations, in Juventae Chasma or Sabaea Terra, as possibly carbonate rocks makes the study of these minerals a prerequisite of remote Martian exploration. Here, we show the protocol for the identification by Raman spectroscopy of different calcium and magnesium carbonates and we present a database of relevance in the search for life, extinct or extant, on Mars; this will be useful for the assessment of data obtained from remote, miniaturized Raman spectrometers now proposed for Mars exploration.

Progress Report on PICA Activities in Support of New Frontiers Missions

NASA Technical Reports Server (NTRS)

Stackpoole, Margaret; Venkatapathy, Ethiraj; Violette, Steve

2017-01-01

Phenolic Impregnated Carbon Ablator (PICA) is a TPS material that has been used in a number of previous flight missions (Stardust, MSL) and is planned for a number of future missions (OSIRIS-Rex and Mars 2020) so it has substantial flight heritage, is applicable to a wide range of missions, and is often baselined as the TPS in future NASA proposal activities. As is common with a number of TPS materials, PICA faces a supply chain issue with the rayon precursor from which the carbon fibers used in the PICA preform are derived. PICA uses a non-woven form of the rayon, which once carbonized, is used in the low-density carbon FiberForm (carbon tile) preform utilized in PICA. Current PICA uses a NASA-qualified non-domestic rayon supplier (Sniace), however the qualified supplier is no longer manufacturing the rayon materials. This activity will address PICA sustainability, by initially carbonizing the remaining stockpile of Sniace rayon precursor. A additional FiberForm manufacturing task from alternate rayon sources is also in progress.

Reviews on current carbon emission reduction technologies and projects and their feasibilities on ships

NASA Astrophysics Data System (ADS)

Wang, Haibin; Zhou, Peilin; Wang, Zhongcheng

2017-06-01

Concern about global climate change is growing, and many projects and researchers are committed to reducing greenhouse gases from all possible sources. International Maritime (IMO) has set a target of 20% CO2 reduction from shipping by 2020 and also presented a series of carbon emission reduction methods, which are known as Energy Efficiency Design Index (EEDI) and Energy Efficiency Operation Indicator (EEOI). Reviews on carbon emission reduction from all industries indicate that, Carbon Capture and Storage (CCS) is an excellent solution to global warming. In this paper, a comprehensive literature review of EEDI and EEOI and CCS is conducted and involves reviewing current policies, introducing common technologies, and considering their feasibilities for marine activities, mainly shipping. Current projects are also presented in this paper, thereby illustrating that carbon emission reduction has been the subject of attention from all over the world. Two case ship studies indicate the economic feasibility of carbon emission reduction and provide a guide for CCS system application and practical installation on ships.

Monitoring CO2 concentration and δ13C in an underground cavity using a commercial isotope ratio infrared spectrometer

NASA Astrophysics Data System (ADS)

Guillon, Sophie; Agrinier, Pierre; Pili, Éric

2015-04-01

CO2 stable carbon isotopes are very attractive in environmental research to investigate both natural and anthropogenic carbon sources. Laser-based isotope ratio infrared spectrometers (IRIS) allow in situ continuous monitoring of CO2 isotopes, and therefore they have a potential for unprecedented understanding of carbon sources and dynamics with a high temporal resolution. Here we present the performance assessment of a commercial IRIS analyzer, including the measurement setup and the data processing scheme that we used. Even if the analyzer performs 1-Hz measurements, an integration time of the order of 1 h is commonly needed to obtain acceptable precision for δ13C. The main sources of uncertainty on δ13C come from the concentration dependence and from the temporal instability of the analyzer. The method is applied to the in situ monitoring of the CO2 carbon isotopes in an underground cavity (Roselend Natural Laboratory, France) during several months. On a weekly timescale, the temporal variability of CO2 is dominated by transient contamination by human breath. Discarding these anthropogenic contaminations, CO2 and δ13C backgrounds do not show diurnal or seasonal fluctuations. A CO2 flux released into the tunnel by the surrounding rocks is measured. The carbon isotope composition of this CO2, identified with a Keeling plot, is consistent with a main production by microbial respiration and a minor production from weathering of carbonate minerals. The presented instrument and application study are relevant to cave monitoring, whether to understand CO2 dynamics in visited and/or painted caves for preservation purposes or to understand paleoclimate recording in speleothems.

Genomic Reconstruction of Carbohydrate Utilization Capacities in Microbial-Mat Derived Consortia

PubMed Central

Leyn, Semen A.; Maezato, Yukari; Romine, Margaret F.; Rodionov, Dmitry A.

2017-01-01

Two nearly identical unicyanobacterial consortia (UCC) were previously isolated from benthic microbial mats that occur in a heliothermal saline lake in northern Washington State. Carbohydrates are a primary source of carbon and energy for most heterotrophic bacteria. Since CO2 is the only carbon source provided, the cyanobacterium must provide a source of carbon to the heterotrophs. Available genomic sequences for all members of the UCC provide opportunity to investigate the metabolic routes of carbon transfer between autotroph and heterotrophs. Here, we applied a subsystem-based comparative genomics approach to reconstruct carbohydrate utilization pathways and identify glycohydrolytic enzymes, carbohydrate transporters and pathway-specific transcriptional regulators in 17 heterotrophic members of the UCC. The reconstructed metabolic pathways include 800 genes, near a one-fourth of which encode enzymes, transporters and regulators with newly assigned metabolic functions resulting in discovery of novel functional variants of carbohydrate utilization pathways. The in silico analysis revealed the utilization capabilities for 40 carbohydrates and their derivatives. Two Halomonas species demonstrated the largest number of sugar catabolic pathways. Trehalose, sucrose, maltose, glucose, and beta-glucosides are the most commonly utilized saccharides in this community. Reconstructed regulons for global regulators HexR and CceR include central carbohydrate metabolism genes in the members of Gammaproteobacteria and Alphaproteobacteria, respectively. Genomics analyses were supplemented by experimental characterization of metabolic phenotypes in four isolates derived from the consortia. Measurements of isolate growth on the defined medium supplied with individual carbohydrates confirmed most of the predicted catabolic phenotypes. Not all consortia members use carbohydrates and only a few use complex polysaccharides suggesting a hierarchical carbon flow from cyanobacteria to each heterotroph. In summary, the genomics-based identification of carbohydrate utilization capabilities provides a basis for future experimental studies of carbon flow in UCC. PMID:28751880

North Atlantic Deep Water Production during the Last Glacial Maximum

PubMed Central

Howe, Jacob N. W.; Piotrowski, Alexander M.; Noble, Taryn L.; Mulitza, Stefan; Chiessi, Cristiano M.; Bayon, Germain

2016-01-01

Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial–interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters. PMID:27256826

Production of Prebiotic Molecule Precursors from Hypervelocity Impact Simulation Experiments on Carbonate Sediments

NASA Astrophysics Data System (ADS)

Farcy, B. J.; Grubisic, A.; Li, X.; Pinnick, V. T.; Sutton, M.; Pavlov, A.; Brinckerhoff, W. B.

2017-12-01

Organic molecules, including amino acids and other biotic precursors, have been shown to form in the cooling and expanding plasma plume generated from hypervelocity impacts through the processes of atomization, ionization, and molecular recombination of impactor and impact surface. Various sources of carbon, such as atmospheric methane and carbonaceous material from meteorites, are known to yield cyano-bearing molecules and simple amino acids from impact plasmas. However, the role of mineralogical carbon has not yet been investigated in this process. We have performed experiments using laser ablation mass spectrometry (LA-MS) to study the negative ion yield of plasma-produced prebiotic molecules. A mixture of 10% NH4Cl and 90% CaCO3 was pressed into a pellet and ablated with a 1064 nm Nd:YAG laser, and the resultant negative ions were measured by a plasma analyzer quadrupole MS. Mass spectra show characteristic peaks at m/z = 26 and m/z = 42, indicating the presence of CN- and CNO- ions. When isotopically labeled 15NH4Cl and Ca13CO3 were used in the sample ablation pellet, the purported CN- and CNO- peaks shifted according to their added isotopic mass. Indeed, comparison of resulting ion formation from momentum-based techniques, such as massive cluster secondary ion mass spectrometry, show comparable fragmentation and recombination of CN- and CNO- ions. These findings show that CN- ions, as well as CN radicals and thus HCN, can be formed during meteoritic bombardment of carbonate minerals. During the late heavy bombardment of the earth from 4.1-3.8 Ga, impact-driven chemistry could have played a dominant role in shaping the earth's early prebiotic inventory and sources of chemical energy. As carbonate sediments are common in the Archean, carbonate deposits are most likely an important contributor of carbon for this process, along with atmospheric and meteoritic carbon sources.

Experimental Constraints on the Stability of Clinopyroxene (+) Magnesite in Iron Bearing Planetary Mantles: Implications for Nakhlite Formation

NASA Technical Reports Server (NTRS)

Martin, Audrey M.; Righter, Kevin

2010-01-01

Carbon is present in various forms in the Earth s upper mantle (carbonate- or diamond-bearing mantle xenoliths, carbonatite magmas, CO2 emissions from volcanoes...). Moreover, there is enough carbon in chondritic material to stabilize carbonates into the mantles of Mars or Venus as well as in the Earth. However, the interactions with iron have to be constrained, because Fe is commonly thought to buffer oxygen fugacity into planetary mantles. [1] and [2] show evidences of the stability of clinopyroxene Ca(Mg,Fe)Si2O6 + magnesite (Mg,Fe)CO3 in the Earth s mantle around 6GPa (about 180km). The stability of oxidized forms of carbon (like magnesite) depends on the oxygen fugacity of the system. In the Earth s mantle, the maximum carbon content is 10000 ppm [3]. The fO2 parameter varies vertically as a function of pressure, but also laterally because of geodynamic processes like subduction. Thus, carbonates, graphite, diamond, C-rich gases and melts are all stable forms of carbon in the Earth s mantle. [4] show that the fO2 variations observed in SNC meteorites can be explained by polybaric graphite-CO-CO2 equilibria in the Martian mantle. [5] inferred from thermodynamic calculations that the stable form of carbon in the source regions of the Martian basalts should be graphite (and/or diamond). After [6], a metasomatizing agent like a CO2-rich melt may infiltrate the mantle source of nakhlites. However, according to [7] and [8], the FeO wt% value in the Martian bulk mantle is more than twice that of the Earth s mantle (KLB-1 composition by [9]). As iron and carbon are two elements with various oxidation states, Fe/C interaction mechanisms must be considered.

Microbial source tracking in impaired watersheds using PhyloChip and machine-learning classification.

PubMed

Dubinsky, Eric A; Butkus, Steven R; Andersen, Gary L

2016-11-15

Sources of fecal indicator bacteria are difficult to identify in watersheds that are impacted by a variety of non-point sources. We developed a molecular source tracking test using the PhyloChip microarray that detects and distinguishes fecal bacteria from humans, birds, ruminants, horses, pigs and dogs with a single test. The multiplexed assay targets 9001 different 25-mer fragments of 16S rRNA genes that are common to the bacterial community of each source type. Both random forests and SourceTracker were tested as discrimination tools, with SourceTracker classification producing superior specificity and sensitivity for all source types. Validation with 12 different mammalian sources in mixtures found 100% correct identification of the dominant source and 84-100% specificity. The test was applied to identify sources of fecal indicator bacteria in the Russian River watershed in California. We found widespread contamination by human sources during the wet season proximal to settlements with antiquated septic infrastructure and during the dry season at beaches during intense recreational activity. The test was more sensitive than common fecal indicator tests that failed to identify potential risks at these sites. Conversely, upstream beaches and numerous creeks with less reliance on onsite wastewater treatment contained no fecal signal from humans or other animals; however these waters did contain high counts of fecal indicator bacteria after rain. Microbial community analysis revealed that increased E. coli and enterococci at these locations did not co-occur with common fecal bacteria, but rather co-varied with copiotrophic bacteria that are common in freshwaters with high nutrient and carbon loading, suggesting runoff likely promoted the growth of environmental strains of E. coli and enterococci. These results indicate that machine-learning classification of PhyloChip microarray data can outperform conventional single marker tests that are used to assess health risks, and is an effective tool for distinguishing numerous fecal and environmental sources of pathogen indicators. Copyright © 2016 Elsevier Ltd. All rights reserved.

Land use change and carbon stock dynamics in Sub-Saharan Africa - Case study of Western Africa - Ghana

NASA Astrophysics Data System (ADS)

Grieco, E.; Chiti, T.; Valentini, R.

2012-04-01

Among different regions of the world, Africa and particularly sub-Saharan Africa (SSA) has contributed less than any other to the greenhouse gas emissions, but it is also the region most vulnerable and the least well equipped to the consequences. In SSA the role of land use change in controlling CO2 emissions may be more critical than in any other regions and perhaps the most uncertain component of the global carbon cycle. The most typical example of incomplete estimates will arise from the lack of reliable data for carbon pools. Three factors account for much of the rest of the uncertainty: (1) initial stocks of carbon in ecosystems affected by land-use change, (2) per hectare changes in carbon stocks in response to different types of land-use change, and (3) legacy effects; that is, the time it takes for carbon stocks to equilibrate following a change in land use. Considering the source of uncertainty and the lack of field data for SSA, the study has been located in Ghana (Jomoro district, Western Region) where forest is the only source of wood for domestic uses and deforestation annual rate was 2.2% for the period 2005-2010. This study analyze the above mentioned gaps by assessing: 1) initial carbon stocks (tropical rain forest), 2) per hectare changes in carbon stocks as consequence of deforestation followed by six different main land uses [tree plantations (rubber, coconut, cocoa, oil palm, mixed plantations) and a secondary forest], 3) dynamics of soil carbon stocks through the time considering chronosequences. When accounting changes in carbon stocks in the UNFCCC framework, it is required to consider 5 carbon pools that are: aboveground biomass, belowground biomass, litter, dead wood and soil. Within REDD+ mechanism it is clear that only aboveground pool has to be always considered, belowground biomass is recommended and the others are facultative. Evidence from official UNFCCC reports suggests that only a very small fraction of developing countries currently reports data on soil carbon, although emissions from soils following deforestation are likely to be significant in many cases. Despite the common understanding about the effects of deforestation on different compartments in terms of carbon stocks (e.g. disappearance of biomass ) variations in soil carbon are much less perceptible, even after a radical change in land use . This study brings in the spotlight the soil reaction to radical land use change in the long run demonstrating that it is not so trifle as commonly believed. Importance of considering soil carbon stock for accounting land use change dynamics is not properly recognized in the international deforestation policies and its influence in mitigating climate change is nowadays neglected but it is really not negligible.

Growth versus metabolic tissue replacement in mouse tissues determined by stable carbon and nitrogen isotope analysis

NASA Astrophysics Data System (ADS)

Macavoy, S. E.; Jamil, T.; Macko, S. A.; Arneson, L. S.

2003-12-01

Stable isotope analysis is becoming an extensively used tool in animal ecology. The isotopes most commonly used for analysis in terrestrial systems are those of carbon and nitrogen, due to differential carbon fractionation in C3 and C4 plants, and the approximately 3‰ enrichment in 15N per trophic level. Although isotope signatures in animal tissues presumably reflect the local food web, analysis is often complicated by differential nutrient routing and fractionation by tissues, and by the possibility that large organisms are not in isotopic equilibrium with the foods available in their immediate environment. Additionally, the rate at which organisms incorporate the isotope signature of a food through both growth and metabolic tissue replacement is largely unknown. In this study we have assessed the rate of carbon and nitrogen isotopic turnover in liver, muscle and blood in mice following a diet change. By determining growth rates, we were able to determine the proportion of tissue turnover caused by growth versus that caused by metabolic tissue replacement. Growth was found to account for approximately 10% of observed tissue turnover in sexually mature mice (Mus musculus). Blood carbon was found to have the shortest half-life (16.9 days), followed by muscle (24.7 days). Liver carbon turnover was not as well described by the exponential decay equations as other tissues. However, substantial liver carbon turnover was observed by the 28th day after diet switch. Surprisingly, these tissues primarily reflect the carbon signature of the protein, rather than carbohydrate, source in their diet. The nitrogen signature in all tissues was enriched by 3 - 5‰ over their dietary protein source, depending on tissue type, and the isotopic turnover rates were comparable to those observed in carbon.

Carbon-Starvation Induces Cross-Resistance to Thermal, Acid, and Oxidative Stress in Serratia marcescens

PubMed Central

Pittman, Joseph R.; Kline, La’Kesha C.; Kenyon, William J.

2015-01-01

The broad host-range pathogen Serratia marcescens survives in diverse host and non-host environments, often enduring conditions in which the concentration of essential nutrients is growth-limiting. In such environments, carbon and energy source starvation (carbon-starvation) is one of the most common forms of stress encountered by S. marcescens. Related members of the family Enterobacteriaceae are known to undergo substantial changes in gene expression and physiology in response to the specific stress of carbon-starvation, enabling non-spore-forming cells to survive periods of prolonged starvation and exposure to other forms of stress (i.e., starvation-induced cross-resistance). To determine if carbon-starvation also results in elevated levels of cross-resistance in S. marcescens, both log-phase and carbon-starved cultures, depleted of glucose before the onset of high cell-density stationary-phase, were grown in minimal media at either 30 °C or 37 °C and were then challenged for resistance to high temperature (50 °C), low pH (pH 2.8), and oxidative stress (15 mM H2O2). In general, carbon-starved cells exhibited a higher level of resistance to thermal stress, acid stress, and oxidative stress compared to log-phase cells. The extent of carbon-starvation-induced cross-resistance was dependent on incubation temperature and on the particular strain of S. marcescens. In addition, strain- and temperature-dependent variations in long-term starvation survival were also observed. The enhanced stress-resistance of starved S. marcescens cells could be an important factor in their survival and persistence in many non-host environments and within certain host microenvironments where the availability of carbon sources is suboptimal for growth. PMID:27682115

Inorganic carbon and fossil organic carbon are source of bias for quantification of sequestered carbon in mine spoil

NASA Astrophysics Data System (ADS)

Vindušková, Olga; Frouz, Jan

2016-04-01

Carbon sequestration in mine soils has been studied as a possibility to mitigate the rising atmospheric CO2 levels and to improve mine soil quality (Vindu\\vsková and Frouz, 2013). Moreover, these soils offer an unique opportunity to study soil carbon dynamics using the chronosequence approach (using a set of sites of different age on similar parent material). However, quantification of sequestered carbon in mine soils is often complicated by fossil organic carbon (e.g., from coal or kerogen) or inorganic carbon present in the spoil. We present a methodology for quantification of both of these common constituents of mine soils. Our recommendations are based on experiments done on post-mining soils in Sokolov basin, Czech Republic. Here, fossil organic carbon is present mainly as kerogen Type I and II and represents 2-6 wt.% C in these soils. Inorganic carbon in these soils is present mainly as siderite (FeCO3), calcite (CaCO3), and dolomite (CaMg(CO3)2). All of these carbonates are often found in the overburden of coal seams thus being a common constituent of post-mining soils in the world. Vindu\\vsková O, Frouz J, 2013. Soil carbon accumulation after open-cast coal and oil shale mining in Northern Hemisphere: a quantitative review. ENVIRONMENTAL EARTH SCIENCES, 69: 1685-1698. Vindu\\vsková O, Dvořáček V, Prohasková A, Frouz J. 2014. Distinguishing recent and fossil organic matter - A critical step in evaluation of post-mining soil development - using near infrared spectroscopy. ECOLOGICAL ENGINEERING. 73: 643-648. Vindu\\vsková O, Sebag D, Cailleau G, Brus J, Frouz J. 2015. Methodological comparison for quantitative analysis of fossil and recently derived carbon in mine soils with high content of aliphatic kerogen. ORGANIC GEOCHEMISTRY, 89-90:14-22.

Microbial ecology of denitrification in biological wastewater treatment.

PubMed

Lu, Huijie; Chandran, Kartik; Stensel, David

2014-11-01

Globally, denitrification is commonly employed in biological nitrogen removal processes to enhance water quality. However, substantial knowledge gaps remain concerning the overall community structure, population dynamics and metabolism of different organic carbon sources. This systematic review provides a summary of current findings pertaining to the microbial ecology of denitrification in biological wastewater treatment processes. DNA fingerprinting-based analysis has revealed a high level of microbial diversity in denitrification reactors and highlighted the impacts of carbon sources in determining overall denitrifying community composition. Stable isotope probing, fluorescence in situ hybridization, microarrays and meta-omics further link community structure with function by identifying the functional populations and their gene regulatory patterns at the transcriptional and translational levels. This review stresses the need to integrate microbial ecology information into conventional denitrification design and operation at full-scale. Some emerging questions, from physiological mechanisms to practical solutions, for example, eliminating nitrous oxide emissions and supplementing more sustainable carbon sources than methanol, are also discussed. A combination of high-throughput approaches is next in line for thorough assessment of wastewater denitrifying community structure and function. Though denitrification is used as an example here, this synergy between microbial ecology and process engineering is applicable to other biological wastewater treatment processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Abiogenic formation of alkanes in the Earth's crust as a minor source for global hydrocarbon reservoirs.

PubMed

Sherwood Lollar, B; Westgate, T D; Ward, J A; Slater, G F; Lacrampe-Couloume, G

2002-04-04

Natural hydrocarbons are largely formed by the thermal decomposition of organic matter (thermogenesis) or by microbial processes (bacteriogenesis). But the discovery of methane at an East Pacific Rise hydrothermal vent and in other crustal fluids supports the occurrence of an abiogenic source of hydrocarbons. These abiogenic hydrocarbons are generally formed by the reduction of carbon dioxide, a process which is thought to occur during magma cooling and-more commonly-in hydrothermal systems during water-rock interactions, for example involving Fischer-Tropsch reactions and the serpentinization of ultramafic rocks. Suggestions that abiogenic hydrocarbons make a significant contribution to economic hydrocarbon reservoirs have been difficult to resolve, in part owing to uncertainty in the carbon isotopic signatures for abiogenic versus thermogenic hydrocarbons. Here, using carbon and hydrogen isotope analyses of abiogenic methane and higher hydrocarbons in crystalline rocks of the Canadian shield, we show a clear distinction between abiogenic and thermogenic hydrocarbons. The progressive isotopic trends for the series of C1-C4 alkanes indicate that hydrocarbon formation occurs by way of polymerization of methane precursors. Given that these trends are not observed in the isotopic signatures of economic gas reservoirs, we can now rule out the presence of a globally significant abiogenic source of hydrocarbons.

Predictive isotopic biogeochemistry: hydrocarbons from anoxic marine basins

NASA Technical Reports Server (NTRS)

Freeman, K. H.; Wakeham, S. G.; Hayes, J. M.

1994-01-01

Carbon isotopic compositions were determined for individual hydrocarbons in water column and sediment samples from the Cariaco Trench and Black Sea. In order to identify hydrocarbons derived from phytoplankton, the isotopic compositions expected for biomass of autotrophic organisms living in surface waters of both localities were calculated based on the concentrations of CO2(aq) and the isotopic compositions of dissolved inorganic carbon. These calculated values are compared to measured delta values for particulate organic carbon and for individual hydrocarbon compounds. Specifically, we find that lycopane is probably derived from phytoplankton and that diploptene is derived from the lipids of chemoautotrophs living above the oxic/anoxic boundary. Three acyclic isoprenoids that have been considered markers for methanogens, pentamethyleicosane and two hydrogenated squalenes, have different delta values and apparently do not derive from a common source. Based on the concentration profiles and isotopic compositions, the C31 and C33 n-alkanes and n-alkenes have a similar source, and both may have a planktonic origin. If so, previously assigned terrestrial origins of organic matter in some Black Sea sediments may be erroneous.

In-situ propellant rocket engines for Mars missions ascent vehicle

NASA Technical Reports Server (NTRS)

Roncace, Elizabeth A.

1991-01-01

When contemplating the human exploration of Mars, many scenarios using various propulsion systems have been considered. One propulsion option among them is a vehicle stage with multiple, pump fed rocket engines capable of operating on propellants available on Mars. This reduces the earth launch mass requirements, resulting in economic and payload benefits. No plentiful sources of hydrogen on Mars have been identified on the surface of Mars, so most commonly used high performance liquid fuels, such as hydrogen and hydrocarbons, can be eliminated as possible in situ propellants. But 95 pct of the Martian atmosphere consists of carbon dioxide, which can be converted into carbon monoxide and oxygen. The carbon monoxide oxygen propellant combination is a candidate for a Martian in situ propellant rocket engine. The feasibility is analyzed of a pump fed engine cycle using the propellant combination of carbon monoxide and oxygen.

In-situ propellant rocket engines for Mars mission ascent vehicle

NASA Technical Reports Server (NTRS)

Roncace, Elizabeth A.

1991-01-01

When comtemplating the human exploration of Mars, many scenarios using various propulsion systems have been considered. One propulsion option among them is a vehicle stage with multiple, pump fed rocket engines capable of operating on propellants available on Mars. This reduces the Earth launch mass requirements, resulting in economic and payload benefits. No plentiful sources of hydrogen on Mars have been identified on the surface of Mars, so most commonly used high performance liquid fuels, such as hydrogen and hydrocarbons, can be eliminated as possible in-situ propellants. But 95 pct. of the Martian atmosphere consists of carbon dioxide, which can be converted into carbon monoxide and oxygen. The carbon monoxide oxygen propellant conbination is a candidate for a Martian in-situ propellant rocket engine. The feasibility is analyzed of a pump fed engine cycle using the propellant combination of carbon monoxide and oxygen.

Ground-Water Temperature, Noble Gas, and Carbon Isotope Data from the Espanola Basin, New Mexico

USGS Publications Warehouse

Manning, Andrew H.

2009-01-01

Ground-water samples were collected from 56 locations throughout the Espanola Basin and analyzed for general chemistry (major ions and trace elements), carbon isotopes (delta 13C and 14C activity) in dissolved inorganic carbon, noble gases (He, Ne, Ar, Kr, Xe, and 3He/4He ratio), and tritium. Temperature profiles were measured at six locations in the southeastern part of the basin. Temperature profiles suggest that ground water generally becomes warmer with distance from the mountains and that most ground-water flow occurs at depths 50 years old, consistent with the 14C ages. Terrigenic He (Heterr) concentrations in ground water are high (log Delta Heterr of 2 to 5) throughout much of the basin. High Heterr concentrations are probably caused by in situ production in the Tesuque Formation from locally high concentrations of U-bearing minerals (Northeast zone only), or by upward diffusive/advective transport of crustal- and mantle-sourced He possibly enhanced by basement piercing faults, or by both. The 3He/4He ratio of Heterr (Rterr) is commonly high (Rterr/Ra of 0.3-2.0, where Ra is the 3He/4He ratio in air) suggesting that Espanola Basin ground water commonly contains mantle-sourced He. The 3He/4He ratio of Heterr is generally the highest in the western and southern parts of the basin, closest to the western border fault system and the Quaternary to Miocene volcanics of the Jemez Mountains and Cerros del Rio.

Just Say No to Carbon Emissions (LBNL Science at the Theater)

ScienceCinema

Ramesh, Ramamoorthy; Zhou, Nan; Oldenburg, Curt

2018-06-15

Learn about three efforts our grandchildren may thank us for: cheap solar energy, bringing energy efficiency to China, and learning how to store carbon deep underground. Can solar energy be dirt cheap? We're all potentially billionaires when it comes to solar energy. The trick is learning how to convert sunlight to electricity using cheap and plentiful materials. Ramamoorthy Ramesh, an innovative materials scientist at Berkeley Lab, will discuss how he and other researchers are working to make photovoltaic cells using the most abundant elements in the Earth's crust -- materials that are literally as common as dirt. Energy efficiency in China: Nan Zhou is a researcher with Berkeley Labs China Energy Group. She will speak about Chinas energy use and the policies that have been implemented to increase energy efficiency and reduce CO2 emission growth. Her work focuses on building China's capacity to evaluate, adopt and implement low-carbon development strategies. Zhou has an architecture degree from China, and a Master and Ph.D. in Engineering from Japan. Understanding geologic carbon sequestration: Even with continued growth of renewable energy sources such as wind and solar, fossil fuels will likely remain cheap and plentiful for decades to come. Geologist Curt Oldenburg, who heads Berkeley Lab's Geologic Carbon Sequestration Program, will discuss a strategy to reduce carbon emissions from coal and natural gas. It involves pumping compressed CO2 captured from large stationary sources into underground rock formations that can store it for geological time scales.

Tracing Carbon Flow from Primary Production to a Gulf Coast Salt Marsh Consumer, the Seaside Sparrow (Ammodramus maritimus)

NASA Astrophysics Data System (ADS)

Johnson, J. J.; Polito, M. J.; Olin, J.

2016-02-01

Determining the relative contributions of primary producers to salt marsh food webs is fundamental to understanding how these systems are structured. Biomarkers such as bulk carbon isotopes (13C/12C) and fatty acids have become popular tracers of trophic dynamics, based on the principle that the composition of biomarkers in consumer tissues is a reflection of the composition of these same biomarkers in a consumer's diet. However, the use of bulk stable isotope and fatty acid analyses to assess carbon flow in food webs is often hampered by confounding factors such as isotopic fractionation and fatty acid modifications that can occur between trophic levels. In contrast, compound-specific stable isotope analysis of amino acids may offer a more precise tracking of carbon flow through complex food webs. This is because the isotopic values of essential amino acids in consumer tissues are assimilated largely unchanged from their primary sources at the base of the food web. The aim of this study was to test the consistency of three different methods (bulk carbon stable isotope, fatty acid and compound-specific stable isotope analyses) while examining the carbon source pool underlying the diet of a common marsh consumer, the seaside sparrow (A. maritimus). This comparison allows us to gain a better idea of the relative merits of these analytical methods and contribute to a clearer model of overall trophic dynamics in a salt marsh food web.

Just Say No to Carbon Emissions (LBNL Science at the Theater)

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

Ramesh, Ramamoorthy; Zhou, Nan; Oldenburg, Curt

2010-04-26

Learn about three efforts our grandchildren may thank us for: cheap solar energy, bringing energy efficiency to China, and learning how to store carbon deep underground. Can solar energy be dirt cheap? We're all potentially billionaires when it comes to solar energy. The trick is learning how to convert sunlight to electricity using cheap and plentiful materials. Ramamoorthy Ramesh, an innovative materials scientist at Berkeley Lab, will discuss how he and other researchers are working to make photovoltaic cells using the most abundant elements in the Earth's crust -- materials that are literally as common as dirt. Energy efficiency inmore » China: Nan Zhou is a researcher with Berkeley Labs China Energy Group. She will speak about Chinas energy use and the policies that have been implemented to increase energy efficiency and reduce CO2 emission growth. Her work focuses on building China's capacity to evaluate, adopt and implement low-carbon development strategies. Zhou has an architecture degree from China, and a Master and Ph.D. in Engineering from Japan. Understanding geologic carbon sequestration: Even with continued growth of renewable energy sources such as wind and solar, fossil fuels will likely remain cheap and plentiful for decades to come. Geologist Curt Oldenburg, who heads Berkeley Lab's Geologic Carbon Sequestration Program, will discuss a strategy to reduce carbon emissions from coal and natural gas. It involves pumping compressed CO2 captured from large stationary sources into underground rock formations that can store it for geological time scales.« less

Production of Dissolved Organic Matter During Doliolid Feeding

NASA Astrophysics Data System (ADS)

Castellane, N. J.; Paffenhofer, G. A.; Stubbins, A.

2016-02-01

The biological carbon pump (BCP) draws carbon dioxide out of the atmosphere and buries it at the seafloor. The efficiency of the BCP is determined in part by the sinking rates of particulate organic carbon (POC) from ocean surface waters. Zooplankton can package POC into fecal pellets with higher sinking rates than their food source (e.g. phytoplankton), increasing the efficiency of the BCP. However, dissolved organic carbon (DOC) is also produced as zooplankton ingest and egest food, reducing the efficiency of BCP. The pelagic tunicate Dolioletta gegenbauri (doliolid) is a gelatinous zooplankton found at high concentrations in shelf waters, including our study site: the South Atlantic Bight. Doliolids are efficient grazers capable of stripping large quantities of phytoplankton from the water column. To determine the balance between pellet formation and DOC production during feeding, doliolids (6-7 mm gonozooids) were placed in natural seawater amended with a live phytoplankton food source and incubated on a plankton wheel. Dissolved organic matter (DOM) released directly to the water as well as the water soluble fraction of pellet organic matter were quantified and optically characterized. Colored dissolved organic matter (CDOM) absorbance and fluorescence spectra revealed that doliolid feeding produces DOM with optical properties that are commonly indicative of newly produced, highly biolabile DOM of microbial origin. Based upon these optical characteristics, doliolid-produced DOM is expected to be highly bio-labile in the environment and therefore rapidly degraded by surface ocean microbes shunting phytoplankton-derived organic carbon out of the BCP and back to dissolved inorganic carbon.

Value-added Synthesis of Graphene: Recycling Industrial Carbon Waste into Electrodes for High-Performance Electronic Devices

PubMed Central

Seo, Hong-Kyu; Kim, Tae-Sik; Park, Chibeom; Xu, Wentao; Baek, Kangkyun; Bae, Sang-Hoon; Ahn, Jong-Hyun; Kim, Kimoon; Choi, Hee Cheul; Lee, Tae-Woo

2015-01-01

We have developed a simple, scalable, transfer-free, ecologically sustainable, value-added method to convert inexpensive coal tar pitch to patterned graphene films directly on device substrates. The method, which does not require an additional transfer process, enables direct growth of graphene films on device substrates in large area. To demonstrate the practical applications of the graphene films, we used the patterned graphene grown on a dielectric substrate directly as electrodes of bottom-contact pentacene field-effect transistors (max. field effect mobility ~0.36 cm2·V−1·s−1), without using any physical transfer process. This use of a chemical waste product as a solid carbon source instead of commonly used explosive hydrocarbon gas sources for graphene synthesis has the dual benefits of converting the waste to a valuable product, and reducing pollution. PMID:26567845

Value-added Synthesis of Graphene: Recycling Industrial Carbon Waste into Electrodes for High-Performance Electronic Devices

NASA Astrophysics Data System (ADS)

Seo, Hong-Kyu; Kim, Tae-Sik; Park, Chibeom; Xu, Wentao; Baek, Kangkyun; Bae, Sang-Hoon; Ahn, Jong-Hyun; Kim, Kimoon; Choi, Hee Cheul; Lee, Tae-Woo

2015-11-01

We have developed a simple, scalable, transfer-free, ecologically sustainable, value-added method to convert inexpensive coal tar pitch to patterned graphene films directly on device substrates. The method, which does not require an additional transfer process, enables direct growth of graphene films on device substrates in large area. To demonstrate the practical applications of the graphene films, we used the patterned graphene grown on a dielectric substrate directly as electrodes of bottom-contact pentacene field-effect transistors (max. field effect mobility ~0.36 cm2·V-1·s-1), without using any physical transfer process. This use of a chemical waste product as a solid carbon source instead of commonly used explosive hydrocarbon gas sources for graphene synthesis has the dual benefits of converting the waste to a valuable product, and reducing pollution.

Value-added Synthesis of Graphene: Recycling Industrial Carbon Waste into Electrodes for High-Performance Electronic Devices.

PubMed

Seo, Hong-Kyu; Kim, Tae-Sik; Park, Chibeom; Xu, Wentao; Baek, Kangkyun; Bae, Sang-Hoon; Ahn, Jong-Hyun; Kim, Kimoon; Choi, Hee Cheul; Lee, Tae-Woo

2015-11-16

We have developed a simple, scalable, transfer-free, ecologically sustainable, value-added method to convert inexpensive coal tar pitch to patterned graphene films directly on device substrates. The method, which does not require an additional transfer process, enables direct growth of graphene films on device substrates in large area. To demonstrate the practical applications of the graphene films, we used the patterned graphene grown on a dielectric substrate directly as electrodes of bottom-contact pentacene field-effect transistors (max. field effect mobility ~0.36 cm(2)·V(-1)·s(-1)), without using any physical transfer process. This use of a chemical waste product as a solid carbon source instead of commonly used explosive hydrocarbon gas sources for graphene synthesis has the dual benefits of converting the waste to a valuable product, and reducing pollution.

Kupier prize lecture: Sources of solar-system carbon

NASA Technical Reports Server (NTRS)

Anders, Edward; Zinner, Ernst

1994-01-01

We have tried to deconvolve Solar-System carbon into its sources, on the basis of C-12/C-13 ratios (equivalent to R). Interstellar SiC in meteorites, representing greater than 4.6-Ga-old stardust from carbon stars, is isotopically heavier (bar R = 38 +/- 2) than Solar-System carbon (89), implying that the latter contains an additional, light component. A likely source are massive stars, mainly Type II supernovae and Wolf-Rayet stars, which, being O-rich, eject their C largely as CO rather than carbonaceous dust. The fraction of such light C in the Solar System depends on R(sub light) in the source. For R(sub light) = 180-1025 (as in 'Group 4' meteoritic graphite spherules, which apparently came from massive stars greater than 4.6 Ga ago), the fraction of light C is 0.79-0.61. Similar results are obtained for present-day data on red giants and interstellar gas. Although both have become enriched in C-13 due to galactic evolution (to bar-R = 20 and 57), the fraction of the light component in interstellar gas again is near 0.7. (Here bar R represents the mean of a mixture calculated via atom fractions; it is not identical to the arithmetic mean R). Interstellar graphite, unlike SiC, shows a large peak at R approximately equal 90, near the solar value. Although some of the grains may be of local origin, others show anomalies in other elements and hence are exotic. Microdiamonds, with R = 93, also are exotic on the basis of their Xe and N. Apparently R approximately 90 was a fairly common composition 4.6 Ga ago, of stars as well as the ISM.

Carbon Catabolite Repression and Impranil Polyurethane Degradation in Pseudomonas protegens Strain Pf-5.

PubMed

Hung, Chia-Suei; Zingarelli, Sandra; Nadeau, Lloyd J; Biffinger, Justin C; Drake, Carrie A; Crouch, Audra L; Barlow, Daniel E; Russell, John N; Crookes-Goodson, Wendy J

2016-10-15

Polyester polyurethane (PU) coatings are widely used to help protect underlying structural surfaces but are susceptible to biological degradation. PUs are susceptible to degradation by Pseudomonas species, due in part to the degradative activity of secreted hydrolytic enzymes. Microorganisms often respond to environmental cues by secreting enzymes or secondary metabolites to benefit their survival. This study investigated the impact of exposing several Pseudomonas strains to select carbon sources on the degradation of the colloidal polyester polyurethane Impranil DLN (Impranil). The prototypic Pseudomonas protegens strain Pf-5 exhibited Impranil-degrading activities when grown in sodium citrate but not in glucose-containing medium. Glucose also inhibited the induction of Impranil-degrading activity by citrate-fed Pf-5 in a dose-dependent manner. Biochemical and mutational analyses identified two extracellular lipases present in the Pf-5 culture supernatant (PueA and PueB) that were involved in degradation of Impranil. Deletion of the pueA gene reduced Impranil-clearing activities, while pueB deletion exhibited little effect. Removal of both genes was necessary to stop degradation of the polyurethane. Bioinformatic analysis showed that putative Cbr/Hfq/Crc-mediated regulatory elements were present in the intergenic sequences upstream of both pueA and pueB genes. Our results confirmed that both PueA and PueB extracellular enzymes act in concert to degrade Impranil. Furthermore, our data showed that carbon sources in the growth medium directly affected the levels of Impranil-degrading activity but that carbon source effects varied among Pseudomonas strains. This study uncovered an intricate and complicated regulation of P. protegens PU degradation activity controlled by carbon catabolite repression. Polyurethane (PU) coatings are commonly used to protect metals from corrosion. Microbiologically induced PU degradation might pose a substantial problem for the integrity of these coatings. Microorganisms from diverse genera, including pseudomonads, possess the ability to degrade PUs via various means. This work identified two extracellular lipases, PueA and PueB, secreted by P. protegens strain Pf-5, to be responsible for the degradation of a colloidal polyester PU, Impranil. This study also revealed that the expression of the degradative activity by strain Pf-5 is controlled by glucose carbon catabolite repression. Furthermore, this study showed that the Impranil-degrading activity of many other Pseudomonas strains could be influenced by different carbon sources. This work shed light on the carbon source regulation of PU degradation activity among pseudomonads and identified the polyurethane lipases in P. protegens. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Carbon Catabolite Repression and Impranil Polyurethane Degradation in Pseudomonas protegens Strain Pf-5

PubMed Central

Hung, Chia-Suei; Zingarelli, Sandra; Nadeau, Lloyd J.; Biffinger, Justin C.; Drake, Carrie A.; Crouch, Audra L.; Barlow, Daniel E.; Russell, John N.

2016-01-01

ABSTRACT Polyester polyurethane (PU) coatings are widely used to help protect underlying structural surfaces but are susceptible to biological degradation. PUs are susceptible to degradation by Pseudomonas species, due in part to the degradative activity of secreted hydrolytic enzymes. Microorganisms often respond to environmental cues by secreting enzymes or secondary metabolites to benefit their survival. This study investigated the impact of exposing several Pseudomonas strains to select carbon sources on the degradation of the colloidal polyester polyurethane Impranil DLN (Impranil). The prototypic Pseudomonas protegens strain Pf-5 exhibited Impranil-degrading activities when grown in sodium citrate but not in glucose-containing medium. Glucose also inhibited the induction of Impranil-degrading activity by citrate-fed Pf-5 in a dose-dependent manner. Biochemical and mutational analyses identified two extracellular lipases present in the Pf-5 culture supernatant (PueA and PueB) that were involved in degradation of Impranil. Deletion of the pueA gene reduced Impranil-clearing activities, while pueB deletion exhibited little effect. Removal of both genes was necessary to stop degradation of the polyurethane. Bioinformatic analysis showed that putative Cbr/Hfq/Crc-mediated regulatory elements were present in the intergenic sequences upstream of both pueA and pueB genes. Our results confirmed that both PueA and PueB extracellular enzymes act in concert to degrade Impranil. Furthermore, our data showed that carbon sources in the growth medium directly affected the levels of Impranil-degrading activity but that carbon source effects varied among Pseudomonas strains. This study uncovered an intricate and complicated regulation of P. protegens PU degradation activity controlled by carbon catabolite repression. IMPORTANCE Polyurethane (PU) coatings are commonly used to protect metals from corrosion. Microbiologically induced PU degradation might pose a substantial problem for the integrity of these coatings. Microorganisms from diverse genera, including pseudomonads, possess the ability to degrade PUs via various means. This work identified two extracellular lipases, PueA and PueB, secreted by P. protegens strain Pf-5, to be responsible for the degradation of a colloidal polyester PU, Impranil. This study also revealed that the expression of the degradative activity by strain Pf-5 is controlled by glucose carbon catabolite repression. Furthermore, this study showed that the Impranil-degrading activity of many other Pseudomonas strains could be influenced by different carbon sources. This work shed light on the carbon source regulation of PU degradation activity among pseudomonads and identified the polyurethane lipases in P. protegens. PMID:27496773

Polygalacturonase production by AR2 pectinolytic bacteria through submerged fermentation of raja nangka banana peel (Musa paradisiaca var. formatypica) with variation of carbon source and pectin

NASA Astrophysics Data System (ADS)

Utami, R.; Widowati, E.; Ivenaria, A.; Mahajoeno, E.

2017-04-01

Polygalacturonase (EC 3.1.2.15) catalyzes the hydrolysis of α-1,4-glycosidic bonds on galacturonic acid. Polygalacturonase can be produced from AR2 pectinolytic bacteria isolated from orange peel and vegetable waste. Commonly cost production of enzymes were high. However, with the advancement of technology, enzymes can now be manufactured at a low cost. Production of enzymes in low cost media with agro-industrial waste is interesting. Raja nangka banana peel is agro-industrial waste that is uneconomic. Therefore, this material can be used as a pectin source in polygalacturonase production. Polygalacturonase was produced by AR2 pectinolytic bacteria with the addition of various carbon sources (1% glucose, 1% galactose, 1% lactose) and variation of pectin concentrations (5%; 7.5%; 10%). This study used submerged fermentation with a cultivation temperature of 55°C and an agitation speed of 144 rpm for a 48-h incubation time. The results showed that variation of carbon sources and pectin concentrations affected the production of polygalacturonase. After 48 h fermentation, the results showed that the number of cells of samples ranged from 8.3 to 9.445 log cells/mL; the used pectin of samples ranged from 87.170-93.745%; and the polygalacturonase activity of samples ranged from 0.030 to 0.151 U/mL. The highest polygalacturonase activity was obtained by production of polygalacturonase on 1% glucose and 10% pectin medium.

High-surface-area mesoporous TiO2 microspheres via one-step nanoparticle self-assembly for enhanced lithium-ion storage

NASA Astrophysics Data System (ADS)

Wang, Hsin-Yi; Chen, Jiazang; Hy, Sunny; Yu, Linghui; Xu, Zhichuan; Liu, Bin

2014-11-01

Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m2 g-1 were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and aggregation of TiO2 nanocrystals leads to the formation of high-surface-area TiO2 microspheres under solvothermal conditions. After a low-temperature post-synthesis calcination, carbonate could be incorporated into TiO2 as a dopant with the carbon source coming from the organic byproducts during the synthesis. Carbonate doping modifies the electronic structure of TiO2 (e.g., Fermi level, Ef), and thus influences its electrochemical properties. Solid electrolyte interface (SEI) formation, which is not common for titania, could be initiated in carbonate-doped TiO2 due to elevated Ef. After removing carbonate dopants by high-temperature calcination, the mesoporous TiO2 microspheres showed much improved performance in lithium insertion and stability at various current rates, attributed to a synergistic effect of high surface area, large pore size and good anatase crystallinity.Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m2 g-1 were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and aggregation of TiO2 nanocrystals leads to the formation of high-surface-area TiO2 microspheres under solvothermal conditions. After a low-temperature post-synthesis calcination, carbonate could be incorporated into TiO2 as a dopant with the carbon source coming from the organic byproducts during the synthesis. Carbonate doping modifies the electronic structure of TiO2 (e.g., Fermi level, Ef), and thus influences its electrochemical properties. Solid electrolyte interface (SEI) formation, which is not common for titania, could be initiated in carbonate-doped TiO2 due to elevated Ef. After removing carbonate dopants by high-temperature calcination, the mesoporous TiO2 microspheres showed much improved performance in lithium insertion and stability at various current rates, attributed to a synergistic effect of high surface area, large pore size and good anatase crystallinity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04729j

An alternative parameter to characterize biogas materials: Available carbon-nitrogen ratio.

PubMed

Wang, Ming; Li, Wenzhe; Li, Pengfei; Yan, Shuiping; Zhang, Yanlin

2017-04-01

Available carbon-nitrogen ratio (AC/N) was proposed as an alternative parameter for evaluating the potential of biogas materials in this paper. In the calculation of AC/N ratio, only the carbon that could be effectively utilized in anaerobic digestion (AD) process is included. Compared with total C/N, AC/N is particularly more suitable for the characterization of biogas materials rich in recalcitrant components. Nine common biogas materials were selected and a series of semi-continuous tests for up to 110days were carried out to investigate the source of available carbon and the relationship between AC/N and the stability of AD process. The results showed that only the carbon existing in proteins, sugars, fat and hemicelluose should be considered as available carbon for anaerobic microbes. Besides, the optimal AC/N for semi-continuous AD process was preliminarily determined to be 11-15. Taken together, our results demonstrate that AC/N is more effective than total C/N in the evaluation of the potential performance of AD process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Computational materials chemistry for carbon capture using porous materials

NASA Astrophysics Data System (ADS)

Sharma, Abhishek; Huang, Runhong; Malani, Ateeque; Babarao, Ravichandar

2017-11-01

Control over carbon dioxide (CO2) release is extremely important to decrease its hazardous effects on the environment such as global warming, ocean acidification, etc. For CO2 capture and storage at industrial point sources, nanoporous materials offer an energetically viable and economically feasible approach compared to chemisorption in amines. There is a growing need to design and synthesize new nanoporous materials with enhanced capability for carbon capture. Computational materials chemistry offers tools to screen and design cost-effective materials for CO2 separation and storage, and it is less time consuming compared to trial and error experimental synthesis. It also provides a guide to synthesize new materials with better properties for real world applications. In this review, we briefly highlight the various carbon capture technologies and the need of computational materials design for carbon capture. This review discusses the commonly used computational chemistry-based simulation methods for structural characterization and prediction of thermodynamic properties of adsorbed gases in porous materials. Finally, simulation studies reported on various potential porous materials, such as zeolites, porous carbon, metal organic frameworks (MOFs) and covalent organic frameworks (COFs), for CO2 capture are discussed.

Understanding the carbon cycle in a Late Quaternary-age limestone aquifer system using radiocarbon of dissolved inorganic and organic carbon

NASA Astrophysics Data System (ADS)

Bryan, Eliza; Meredith, Karina T.; Baker, Andy; Andersen, Martin S.; Post, Vincent E. A.

2017-04-01

Estimating groundwater residence time is critical for our understanding of hydrogeological systems, for groundwater resource assessments and for the sustainable management of groundwater resources. Due to its capacity to date groundwater up to 30 thousand years old, as well as the ubiquitous nature of dissolved carbon (as organic and inorganic forms) in groundwater, 14C is the most widely used radiogenic dating technique in regional aquifers. However, the geochemistry of carbon in groundwater systems includes interaction with the atmosphere, biosphere and geosphere, which results in multiple sources and sinks of carbon that vary in time and space. Identifying these sources of carbon and processes relating to its release or removal is important for understanding the evolution of the groundwater and essential for residence time calculations. This study investigates both the inorganic and organic facets of the carbon cycle in groundwaters throughout a freshwater lens and mixing zone of a carbonate island aquifer and identifies the sources of carbon that contribute to the groundwater system. Groundwater samples were collected from shallow (5-20 m) groundwater wells on a small carbonate Island in Western Australia in September 2014 and analysed for major and minor ions, stable water isotopes (SWIs: δ18O, δ2H), 3H, 14C and 13C carbon isotope values of both DIC and DOC, and 3H. The composition of groundwater DOC was investigated by Liquid Chromatography-Organic Carbon Detection (LC-OCD) analysis. The presence of 3H (0.12 to 1.35 TU) in most samples indicates that groundwaters on the Island are modern, however the measured 14CDIC values (8.4 to 97.2 pmc) suggest that most samples are significantly older due to carbonate dissolution and recrystallisation reactions that are identified and quantified in this work. 14CDOC values (46.6 to 105.6 pMC) were higher than 14CDIC values and were well correlated with 3H values, however deeper groundwaters had lower 14CDOC values than expected. LC-OCD chromatography of these groundwaters were found to contain higher concentrations of humic substances, that are most likely attributed to the presence of paleosol horizons at depth in the limestone, which are a common feature in aeolianite deposits along the Western coast of Australia and are related to Quaternary sea level change. The paleosols likely contribute old organic matter to the deeper groundwaters, which may explain the lower 14CDOC values. This study has shown that a combined approach that utilises both DIC and DOC tracers, as well as 3H, is required to identify the sources and evolution of carbon in a groundwater system, as well as the processes that effect the application of 14C dating to groundwaters within a carbonate aquifer.

Optimization of Carbon and Nitrogen Sources for Extracellular Polymeric Substances Production by Chryseobacterium indologenes MUT.2

PubMed Central

Khani, Mojtaba; Bahrami, Ali; Chegeni, Asma; Ghafari, Mohammad Davoud; Mansouran Zadeh, ALi

2016-01-01

Background Bacterial Extracellular Polymeric Substances (EPS) are environmental friendly and versatile polymeric materials that are used in a wide range of industries such as: food, textile, cosmetics, and pharmaceuticals. To make the production process of the EPS cost-effective, improvements in the production yield is required which could be implemented through application of processes such as optimized culture conditions, and development of the strains with higher yield (e.g. through genetic manipulation), or using low-cost substrates. Objectives In this work, the effects of carbon and nitrogen sources were studied in order to improve the EPS production by the submerged cultivation of Chryseobacterium indologenes MUT.2. Materials and Methods The mesophilic microorganism Chryseobacterium indologenes MUT.2, was grown and maintained in the Luria Bertani agar. The initial basal medium contained: glucose (20 g.L-1), yeast extracts (5 g.L-1), K2HPO4 (6 g.L-1), NaH2PO4 (7 g.L-1), NH4CL (0.7 g.L-1), and MgSO4 (0.5 g.L-1). For evaluating the carbon and nitrogen sources’ effect on the fermentation performance, cultures were prepared in 500 mL flasks filled with 300 mL of the medium. The single-factor experiments based on statistics was employed to evaluate and optimize the carbon and nitrogen sources for EPS production in the liquid culture medium of Chryseobacterium indologenes MUT.2. Results The preferred carbon-sources, sucrose and glucose, commonly gave the highest EPS production of 8.32 and 6.37 g.L-1, respectively, and the maximum EPS production of 8.87 g.L-1 was achieved when glutamic acid (5 g.L-1) was employed as the nitrogen source. Conclusions In this work, the culture medium for production of EPS by Chryseobacterium indologenes MUT.2 was optimized. Compared to the basal culture medium in shake-flasks and stirred tank bioreactor, the use of optimized culture medium has resulted in a 53% and 73% increase in the EPS production, respectively. PMID:28959321

The trophic position of the alien crab Rhithropanopeus harrisii (crustacea decapoda panopeidae) in the Taman Bay, Sea of Azov community

NASA Astrophysics Data System (ADS)

Zalota, A. K.; Kolyuchkina, G. A.; Tiunov, A. V.; Biriukova, S. V.; Spiridonov, V. A.

2017-03-01

This work concerns the trophic web positioning of the alien crab Rhithropanopeus harrisii and other common marine invertebrate species and fishes in the benthic ecosystem of the shallows of Taman Bay, Sea of Azov. The base of the trophic web in this system is composed of phytoplankton, macrophytes (algae and marine grasses), and reeds that use atmospheric carbon for photosynthesis. Analysis of the isotopic composition of nitrogen and carbon has shown that although marine grasses are dominating primary producers in the shallows of the bay, primary consumers (such as Cerastoderma glaucum, Porifera gen. sp., Gammarus aequicauda, Deshayesorchestia deshayesii and Idotea balthica) only partially use this organic source; instead, they use a combination of different sources of primary production. It has been shown that the food source of the alien crab is primarily of animal origin. In Taman Bay, R. harrisii is on the same trophic level as other carnivores/scavengers: benthic fishes Syngnathus nigrolineatus, Gobius spp. and native crab Pilumnus hirtellus and shrimp Palaemon adspersus.

Metabolic analyses of the improved ε-poly-L-lysine productivity using a glucose-glycerol mixed carbon source in chemostat cultures.

PubMed

Zhang, Jian-Hua; Zeng, Xin; Chen, Xu-Sheng; Mao, Zhong-Gui

2018-04-21

The glucose-glycerol mixed carbon source remarkably reduced the batch fermentation time of ε-poly-L-lysine (ε-PL) production, leading to higher productivity of both biomass and ε-PL, which was of great significance in industrial microbial fermentation. Our previous study confirmed the positive influence of fast cell growth on the ε-PL biosynthesis, while the direct influence of mixed carbon source on ε-PL production was still unknown. In this work, chemostat culture was employed to study the capacity of ε-PL biosynthesis in different carbon sources at a same dilution rate of 0.05 h -1 . The results indicated that the mixed carbon source could enhance the ε-PL productivity besides the rapid cell growth. Analysis of key enzymes demonstrated that the activities of phosphoenolpyruvate carboxylase, citrate synthase, aspartokinase and ε-PL synthetase were all increased in chemostat culture with the mixed carbon source. In addition, the carbon fluxes were also improved in the mixed carbon source in terms of tricarboxylic acid cycle, anaplerotic and diaminopimelate pathway. Moreover, the mixed carbon source also accelerated the energy metabolism, leading to higher levels of energy charge and NADH/NAD + ratio. The overall improvements of primary metabolism in chemostat culture with glucose-glycerol combination provided sufficient carbon skeletons and ATP for ε-PL biosynthesis. Therefore, the significantly higher ε-PL productivity in the mixed carbon source was a combined effect of both superior substrate group and rapid cell growth.

Alteration of fault rocks by CO2-bearing fluids with implications for sequestration

NASA Astrophysics Data System (ADS)

Luetkemeyer, P. B.; Kirschner, D. L.; Solum, J. G.; Naruk, S.

2011-12-01

Carbonates and sulfates commonly occur as primary (diagenetic) pore cements and secondary fluid-mobilized veins within fault zones. Stable isotope analyses of calcite, formation fluid, and fault zone fluids can help elucidate the carbon sources and the extent of fluid-rock interaction within a particular reservoir. Introduction of CO2 bearing fluids into a reservoir/fault system can profoundly affect the overall fluid chemistry of the reservoir/fault system and may lead to the enhancement or degradation of porosity within the fault zone. The extent of precipitation and/or dissolution of minerals within a fault zone can ultimately influence the sealing properties of a fault. The Colorado Plateau contains a number of large carbon dioxide reservoirs some of which leak and some of which do not. Several normal faults within the Paradox Basin (SE Utah) dissect the Green River anticline giving rise to a series of footwall reservoirs with fault-dependent columns. Numerous CO2-charged springs and geysers are associated with these faults. This study seeks to identify regional sources and subsurface migration of CO2 to these reservoirs and the effect(s) faults have on trap performance. Data provided in this study include mineralogical, elemental, and stable isotope data for fault rocks, host rocks, and carbonate veins that come from two localities along one fault that locally sealed CO2. This fault is just tens of meters away from another normal fault that has leaked CO2-charged waters to the land surface for thousands of years. These analyses have been used to determine the source of carbon isotopes from sedimentary derived carbon and deeply sourced CO2. XRF and XRD data taken from several transects across the normal faults are consistent with mechanical mixing and fluid-assisted mass transfer processes within the fault zone. δ13C range from -6% to +10% (PDB); δ18O values range from +15% to +24% (VSMOW). Geochemical modeling software is used to model the alteration productions of fault rocks from fluids of various chemistries coming from several different reservoirs within an active CO2-charged fault system. These results are compared to data obtained in the field.

Source attribution of black carbon in Arctic snow.

PubMed

Hegg, Dean A; Warren, Stephen G; Grenfell, Thomas C; Doherty, Sarah J; Larson, Timothy V; Clarke, Antony D

2009-06-01

Snow samples obtained at 36 sites in Alaska, Canada, Greenland, Russia, and the Arctic Ocean in early 2007 were analyzed for light-absorbing aerosol concentration together with a suite of associated chemical species. The light absorption data, interpreted as black carbon concentrations, and other chemical data were input into the EPA PMF 1.1 receptor model to explore the sources for black carbon in the snow. The analysis found four factors or sources: two distinct biomass burning sources, a pollution source, and a marine source. The first three of these were responsible for essentially all of the black carbon, with the two biomass sources (encompassing both open and closed combustion) together accounting for >90% of the black carbon.

Estimating carbon and nitrogen pools in a forest soil: Influence of soil bulk density methods and rock content

Treesearch

Martin F. Jurgensen; Deborah S. Page-Dumroese; Robert E. Brown; Joanne M. Tirocke; Chris A. Miller; James B. Pickens; Min Wang

2017-01-01

Soils with high rock content are common in many US forests, and contain large amounts of stored C. Accurate measurements of soil bulk density and rock content are critical for calculating and assessing changes in both C and nutrient pool size, but bulk density sampling methods have limitations and sources of variability. Therefore, we evaluated the use of small-...

Nutrient Exchange and Regulation in Arbuscular Mycorrhizal Symbiosis.

PubMed

Wang, Wanxiao; Shi, Jincai; Xie, Qiujin; Jiang, Yina; Yu, Nan; Wang, Ertao

2017-09-12

Most land plants form symbiotic associations with arbuscular mycorrhizal (AM) fungi. These are the most common and widespread terrestrial plant symbioses, which have a global impact on plant mineral nutrition. The establishment of AM symbiosis involves recognition of the two partners and bidirectional transport of different mineral and carbon nutrients through the symbiotic interfaces within the host root cells. Intriguingly, recent discoveries have highlighted that lipids are transferred from the plant host to AM fungus as a major carbon source. In this review, we discuss the transporter-mediated transfer of carbon, nitrogen, phosphate, potassium and sulfate, and present hypotheses pertaining to the potential regulatory mechanisms of nutrient exchange in AM symbiosis. Current challenges and future perspectives on AM symbiosis research are also discussed. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

Organic carbon sources and controlling processes on aquifer arsenic cycling in the Jianghan Plain, central China.

PubMed

Yu, Kai; Gan, Yiqun; Zhou, Aiguo; Liu, Chongxuan; Duan, Yanhua; Han, Li; Zhang, Yanan

2018-05-30

Groundwater arsenic contamination is a common environmental problem that threatens the health of over 100 million people globally. Apparent seasonal fluctuations in groundwater arsenic concentrations have been reported in various locations worldwide, including the Jianghan Plain, central China. This phenomenon has been attributed to shifts in redox conditions induced by seasonal incursions of surface water. However, it is not clear what processes during the incursion lead to changes in the redox conditions and what is the source of the organic carbon driving these processes. Therefore, we conducted a long-term investigation of stable carbon isotopic compositions in surface water and groundwater, as well as long-term monitoring of hydraulic gradients and geochemical compositions at the Jianghan Plain. Results indicated that a series of biogeochemical processes occurred during surface water incursion, including aerobic microbial respiration, nitrate and sulfate reduction. Groundwater arsenic was removed by adsorption on iron oxyhydroxides produced during oxidation of ferrous iron, resulting in dramatic decreases in arsenic concentrations during surface water recharge seasons. These processes were likely driven by organic carbon vertically transported from surface water and released from the surficial aquitard above 15 m. Groundwater pumping may accelerate the vertical infiltration of oxidizing recharge water and drive exogenous organic carbon to depth. Findings of this study advance the understandings of the mechanisms that cause temporal variations in groundwater As and the importance of exogenous organic carbon that may influence the temporal behavior of arsenic in groundwater. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dry season limnological conditions and basin geology exhibit complex relationships with δ13C and δ15N of carbon sources in four Neotropical floodplains.

PubMed

Zaia Alves, Gustavo H; Hoeinghaus, David J; Manetta, Gislaine I; Benedito, Evanilde

2017-01-01

Studies in freshwater ecosystems are seeking to improve understanding of carbon flow in food webs and stable isotopes have been influential in this work. However, variation in isotopic values of basal production sources could either be an asset or a hindrance depending on study objectives. We assessed the potential for basin geology and local limnological conditions to predict stable carbon and nitrogen isotope values of six carbon sources at multiple locations in four Neotropical floodplain ecosystems (Paraná, Pantanal, Araguaia, and Amazon). Limnological conditions exhibited greater variation within than among systems. δ15N differed among basins for most carbon sources, but δ13C did not (though high within-basin variability for periphyton, phytoplankton and particulate organic carbon was observed). Although δ13C and δ15N values exhibited significant correlations with some limnological factors within and among basins, those relationships differed among carbon sources. Regression trees for both carbon and nitrogen isotopes for all sources depicted complex and in some cases nested relationships, and only very limited similarity was observed among trees for different carbon sources. Although limnological conditions predicted variation in isotope values of carbon sources, we suggest the resulting models were too complex to enable mathematical corrections of source isotope values among sites based on these parameters. The importance of local conditions in determining variation in source isotope values suggest that isotopes may be useful for examining habitat use, dispersal and patch dynamics within heterogeneous floodplain ecosystems, but spatial variability in isotope values needs to be explicitly considered when testing ecosystem models of carbon flow in these systems.

Dry season limnological conditions and basin geology exhibit complex relationships with δ13C and δ15N of carbon sources in four Neotropical floodplains

PubMed Central

Hoeinghaus, David J.; Manetta, Gislaine I.; Benedito, Evanilde

2017-01-01

Studies in freshwater ecosystems are seeking to improve understanding of carbon flow in food webs and stable isotopes have been influential in this work. However, variation in isotopic values of basal production sources could either be an asset or a hindrance depending on study objectives. We assessed the potential for basin geology and local limnological conditions to predict stable carbon and nitrogen isotope values of six carbon sources at multiple locations in four Neotropical floodplain ecosystems (Paraná, Pantanal, Araguaia, and Amazon). Limnological conditions exhibited greater variation within than among systems. δ15N differed among basins for most carbon sources, but δ13C did not (though high within-basin variability for periphyton, phytoplankton and particulate organic carbon was observed). Although δ13C and δ15N values exhibited significant correlations with some limnological factors within and among basins, those relationships differed among carbon sources. Regression trees for both carbon and nitrogen isotopes for all sources depicted complex and in some cases nested relationships, and only very limited similarity was observed among trees for different carbon sources. Although limnological conditions predicted variation in isotope values of carbon sources, we suggest the resulting models were too complex to enable mathematical corrections of source isotope values among sites based on these parameters. The importance of local conditions in determining variation in source isotope values suggest that isotopes may be useful for examining habitat use, dispersal and patch dynamics within heterogeneous floodplain ecosystems, but spatial variability in isotope values needs to be explicitly considered when testing ecosystem models of carbon flow in these systems. PMID:28358822

Characterization of emissions from South Asian biofuels and application to source apportionment of carbonaceous aerosol in the Himalayas

NASA Astrophysics Data System (ADS)

Stone, Elizabeth A.; Schauer, James J.; Pradhan, Bidya Banmali; Dangol, Pradeep Man; Habib, Gazala; Venkataraman, Chandra; Ramanathan, V.

2010-03-01

This study focuses on improving source apportionment of carbonaceous aerosol in South Asia and consists of three parts: (1) development of novel molecular marker-based profiles for real-world biofuel combustion, (2) application of these profiles to a year-long data set, and (3) evaluation of profiles by an in-depth sensitivity analysis. Emissions profiles for biomass fuels were developed through source testing of a residential stove commonly used in South Asia. Wood fuels were combusted at high and low rates, which corresponded to source profiles high in organic carbon (OC) or high in elemental carbon (EC), respectively. Crop wastes common to the region, including rice straw, mustard stalk, jute stalk, soybean stalk, and animal residue burnings, were also characterized. Biofuel profiles were used in a source apportionment study of OC and EC in Godavari, Nepal. This site is located in the foothills of the Himalayas and was selected for its well-mixed and regionally impacted air masses. At Godavari, daily samples of fine particulate matter (PM2.5) were collected throughout the year of 2006, and the annual trends in particulate mass, OC, and EC followed the occurrence of a regional haze in South Asia. Maximum concentrations occurred during the dry winter season and minimum concentrations occurred during the summer monsoon season. Specific organic compounds unique to aerosol sources, molecular markers, were measured in monthly composite samples. These markers implicated motor vehicles, coal combustion, biomass burning, cow dung burning, vegetative detritus, and secondary organic aerosol as sources of carbonaceous aerosol. A molecular marker-based chemical mass balance (CMB) model provided a quantitative assessment of primary source contributions to carbonaceous aerosol. The new profiles were compared to widely used biomass burning profiles from the literature in a sensitivity analysis. This analysis indicated a high degree of stability in estimates of source contributions to OC when different biomass profiles were used. The majority of OC was unapportioned to primary sources and was estimated to be of secondary origin, while biomass combustion was the next-largest source of OC. The CMB apportionment of EC to primary sources was unstable due to the diversity of biomass burning conditions in the region. The model results suggested that biomass burning and fossil fuel were important contributors to EC, but could not reconcile their relative contributions.

Differences in carbon source utilization of Salmonella Oranienburg and Saintpaul isolated from river water.

PubMed

Medrano-Félix, Andrés; Estrada-Acosta, Mitzi; Peraza-Garay, Felipe; Castro-Del Campo, Nohelia; Martínez-Urtaza, Jaime; Chaidez, Cristóbal

2017-08-01

Long-term exposure to river water by non-indigenous micro-organisms such as Salmonella may affect metabolic adaptation to carbon sources. This study was conducted to determine differences in carbon source utilization of Salmonella Oranienburg and Salmonella Saintpaul (isolated from tropical river water) as well as the control strain Salmonella Typhimurium exposed to laboratory, river water, and host cells (Hep-2 cell line) growth conditions. Results showed that Salmonella Oranienburg and Salmonella Saintpaul showed better ability for carbon source utilization under the three growth conditions evaluated; however, S. Oranienburg showed the fastest and highest utilization on different carbon sources, including D-Glucosaminic acid, N-acetyl-D-Glucosamine, Glucose-1-phosphate, and D-Galactonic acid, while Salmonella Saintpaul and S. Typhimurium showed a limited utilization of carbon sources. In conclusion, this study suggests that environmental Salmonella strains show better survival and preconditioning abilities to external environments than the control strain based on their plasticity on diverse carbon sources use.

Impact of Microbial Growth on Subsurface Perfluoroalkyl Acid Transport

NASA Astrophysics Data System (ADS)

Weathers, T. S.; Higgins, C. P.; Sharp, J.

2014-12-01

The fate and transport of poly and perfluoroalkyl substances (PFASs) in the presence of active microbial communities has not been widely investigated. These emerging contaminants are commonly utilized in aqueous film-forming foams (AFFF) and have often been detected in groundwater. This study explores the transport of a suite of perfluorocarboxylic acids and perfluoroalkylsulfonates, including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in microbially active settings. Single point organic carbon normalized sorption coefficients derived by exposing inactive cellular material to PFASs result in more than an order of magnitude increase in sorption compared to soil organic carbon sorption coefficients found in literature. For example, the sorption coefficients for PFOS are 4.05±0.07 L/kg and 2.80±0.08 L/kg for cellular organic carbon and soil organic carbon respectively. This increase in sorption, coupled with enhanced extracellular polymeric substance production observed during growth of a common hydrocarbon degrading soil microbe exposed to source-level concentrations of PFASs (10 mg/L of 11 analytes, 110 mg/L total) may result in PFAS retardation in situ. To address the upscaling of this phenomenon, flow-through columns packed with low-organic carbon sediment and biostimulated with 10 mg/L glucose were exposed to PFAS concentrations from 15 μg/L to 10 mg/L of each 11 analytes. Breakthrough and tailing of each analyte was measured and modeled with Hydrus-1D to explore sorption coefficients over time for microbially active columns.

The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep

USGS Publications Warehouse

Mills, Christopher T.; Slater, Gregory F.; Dias, Robert F.; Carr, Stephanie A.; Reddy, Christopher M.; Schmidt, Raleigh; Mandernack, Kevin W.

2013-01-01

Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH4 and also a likely source of ancient (i.e. 14C-dead) carbon to soil microbial communities. Natural abundance 13C and 14C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO2 and CH4 were used to assess the incorporation of CBM-derived carbon into methanotrophs and other members of the soil microbial community. Concentrations of type I and type II methanotroph PLFA biomarkers (16:1ω8c and 18:1ω8c, respectively) were elevated in CBM-impacted soils compared with a control site. Comparison of PLFA and 16s rDNA data suggested type I and II methanotroph populations were well estimated and overestimated by their PLFA biomarkers, respectively. The δ13C values of PLFAs common in type I and II methanotrophs were as negative as −67‰ and consistent with the assimilation of CBM. PLFAs more indicative of nonmethanotrophic bacteria had δ13C values that were intermediate indicating assimilation of both plant- and CBM-derived carbon. Δ14C values of select PLFAs (−351 to −936‰) indicated similar patterns of CBM assimilation by methanotrophs and nonmethanotrophs and were used to estimate that 35–91% of carbon assimilated by nonmethanotrophs was derived from CBM depending on time of sampling and soil depth.

Nucleobase and amino acid formation through impacts of meteorites on the early ocean

NASA Astrophysics Data System (ADS)

Furukawa, Yoshihiro; Nakazawa, Hiromoto; Sekine, Toshimori; Kobayashi, Takamichi; Kakegawa, Takeshi

2015-11-01

The emergence of life's building blocks on the prebiotic Earth was the first crucial step for the origins of life. Extraterrestrial delivery of intact amino acids and nucleobases is the prevailing hypothesis for their availability on prebiotic Earth because of the difficulties associated with the production of these organics from terrestrial carbon and nitrogen sources under plausible prebiotic conditions. However, the variety and amounts of these intact organics delivered by meteorites would have been limited. Previous shock-recovery experiments have demonstrated that meteorite impact reactions could have generated organics on the prebiotic Earth. Here, we report on the simultaneous formation of nucleobases (cytosine and uracil) found in DNA and/or RNA, various proteinogenic amino acids (glycine, alanine, serine, aspartic acid, glutamic acid, valine, leucine, isoleucine, and proline), non-proteinogenic amino acids, and aliphatic amines in experiments simulating reactions induced by extraterrestrial objects impacting on the early oceans. To the best of our knowledge, this is the first report of the formation of nucleobases from inorganic materials by shock conditions. In these experiments, bicarbonate was used as the carbon source. Bicarbonate, which is a common dissolved carbon species in CO2-rich atmospheric conditions, was presumably the most abundant carbon species in the early oceans and in post-impact plumes. Thus, the present results expand the possibility that impact-induced reactions generated various building blocks for life on prebiotic Earth in large quantities through the use of terrestrial carbon reservoirs.

Particulate matter chemical component concentrations and sources in settings of household solid fuel use.

PubMed

Secrest, M H; Schauer, J J; Carter, E M; Baumgartner, J

2017-11-01

Particulate matter (PM) air pollution derives from combustion and non-combustion sources and consists of various chemical species that may differentially impact human health and climate. Previous reviews of PM chemical component concentrations and sources focus on high-income urban settings, which likely differ from the low- and middle-income settings where solid fuel (ie, coal, biomass) is commonly burned for cooking and heating. We aimed to summarize the concentrations of PM chemical components and their contributing sources in settings where solid fuel is burned. We searched the literature for studies that reported PM component concentrations from homes, personal exposures, and direct stove emissions under uncontrolled, real-world conditions. We calculated weighted mean daily concentrations for select PM components and compared sources of PM determined by source apportionment. Our search criteria yielded 48 studies conducted in 12 countries. Weighted mean daily cooking area concentrations of elemental carbon, organic carbon, and benzo(a)pyrene were 18.8 μg m -3 , 74.0 μg m -3 , and 155 ng m -3 , respectively. Solid fuel combustion explained 29%-48% of principal component/factor analysis variance and 41%-87% of PM mass determined by positive matrix factorization. Multiple indoor and outdoor sources impacted PM concentrations and composition in these settings, including solid fuel burning, mobile emissions, dust, and solid waste burning. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Plant resource history effects on contemporary microbial processes

NASA Astrophysics Data System (ADS)

Bradford, Mark

2010-05-01

Background/Questions/Methods Soil microbial communities play a pivotal role in providing ecosystem services, given that they are key drivers of biogeochemical processes such as carbon and nitrogen cycling. As species-rich communities, made-up of populations with short generation times, it is commonly assumed that there is a high degree of functional redundancy within soil communities with respect to broad-physiological processes, such as organic carbon decomposition. This assumption underlies the majority of terrestrial ecosystem models, where relationships between processes and controlling factors are parameterized using statistical relationships generated from measurements across space. However, microbial communities display biogeographic patterns, even at fine scales and it is possible that these patterns extend to influence their function. I first present experiments that combine common garden and reciprocal transplant approaches to test whether microbial communities sourced from distinct habitats across the contiguous United States exhibit functional similarity (i.e. redundancy) or dissimilarity in common environments. The environments are experimental microcosms composed of leaf litters differing markedly in recalcitrance. Following inoculation with the microbial communities, decomposition rates are followed across 300 days. Next, using a similar experimental microcosm design, I present experiments that test whether a common resource history might cause communities, which are initially dissimilar, to converge functionally. Distinct microbial communities are introduced into a fresh litter environment every 100 days for 300 days total. Finally, I present an experiment to test whether functional convergence (either partial or complete) is associated with a reduction in function in alternate environments (essentially a functional ‘trade-off'). In this last experiment decomposition rates are measured for 100 days in alternate environments following 300 days of successive exposure to a single litter type. Results/Conclusions I show in the first experiment that rates of carbon dioxide production from litter decomposition are strongly dependent on the microbial inoculum, with differences in the microbial community alone accounting for substantial (up to 85%) variation in total carbon mineralized. Communities that share a common history with a given foliar litter exhibit higher decomposition rates when compared to communities foreign to that habitat, suggestive of local adaptation. In the second experiment, decomposition rates (measured as cumulative carbon dioxide values per 100-day run) converge partially in the second 100-day run, and cumulative values for all six inocula increase toward the highest values observed in the initial 100-day run. Convergence continues but at a reduced rate in the third 100-day run; yet increases in function appear to asymptote. The increasing similarity in cumulative values between inocula, observed in the successive 100-day runs, is consistent with partial functional convergence of communities exposed to a common environment. In the final experiment, microbial inocula crossed to an alternate environment (e.g. those communities maintained in a grass environment then inoculated into a hardwood litter environment) results in cumulative values in the alternate environments that are approximately half those observed for communities inoculated into the same environment. Collectively, our results suggest that the implicit assumption in ecosystem models (i.e. microbial communities in the same environment are functionally equivalent) is incorrect. The increasing similarity across time in function in common environments of inocula sourced from different resource habitats shows the potential for function to converge. Yet this convergence is only partial and is associated with "apparent' trade-offs in the ability to decompose substrates from the original environments from which the inocula were sourced. To predict accurately how biogeochemical processes will respond to global change may require consideration of the community composition and/or adaptation of microbial communities to past resource environments and the consequences of their (partial) adaptation to new ones.

Repression of Pseudomonas putida phenanthrene-degrading activity by plant root extracts and exudates.

PubMed

Rentz, Jeremy A; Alvarez, Pedro J J; Schnoor, Jerald L

2004-06-01

The phenanthrene-degrading activity (PDA) of Pseudomonas putida ATCC 17484 was repressed after incubation with plant root extracts of oat (Avena sativa), osage orange (Maclura pomifera), hybrid willow (Salix alba x matsudana), kou (Cordia subcordata) and milo (Thespesia populnea) and plant root exudates of oat (Avena sativa) and hybrid poplar (Populus deltoides x nigra DN34). Total organic carbon content of root extracts ranged from 103 to 395 mg l(-1). Characterization of root extracts identified acetate (not detectable to 8.0 mg l(-1)), amino acids (1.7-17.3 mg l(-1)) and glucose (1.6-14.0 mg l(-1)), indicating a complex mixture of substrates. Repression was also observed after exposure to potential root-derived substrates, including organic acids, glucose (carbohydrate) and glutamate (amino acid). Carbon source regulation (e.g. catabolite repression) was apparently responsible for the observed repression of P. putida PDA by root extracts. However, we showed that P. putida grows on root extracts and exudates as sole carbon and energy sources. Enhanced growth on root products may compensate for partial repression, because larger microbial populations are conducive to faster degradation rates. This would explain the commonly reported increase in phenanthrene removal in the rhizosphere.

Unidirectional, dual-comb lasing under multiple pulse formation mechanisms in a passively mode-locked fiber ring laser.

PubMed

Liu, Ya; Zhao, Xin; Hu, Guoqing; Li, Cui; Zhao, Bofeng; Zheng, Zheng

2016-09-19

Dual-comb lasers simultaneously generating asynchronous ultrashort pulses could be an intriguing alternative to the current dual-laser comb source. When generated through a common light path, the low common-mode noises and good coherence between the pulse trains could be realized. Here we demonstrate the completely common-path, unidirectional dual-comb lasing using a carbon nanotube saturable absorber with additional pulse narrowing and broadening mechanisms. The interactions between multiple soliton formation mechanisms result in bifurcation into unusual two-pulse states with pulses of four-fold bandwidth difference and tens-of-Hz repetition rate difference. Coherence between the pulses is verified by the asynchronous cross-sampling and dual-comb spectroscopy measurements.

Quantifying uncertainty in carbon and nutrient pools of coarse woody debris

NASA Astrophysics Data System (ADS)

See, C. R.; Campbell, J. L.; Fraver, S.; Domke, G. M.; Harmon, M. E.; Knoepp, J. D.; Woodall, C. W.

2016-12-01

Woody detritus constitutes a major pool of both carbon and nutrients in forested ecosystems. Estimating coarse wood stocks relies on many assumptions, even when full surveys are conducted. Researchers rarely report error in coarse wood pool estimates, despite the importance to ecosystem budgets and modelling efforts. To date, no study has attempted a comprehensive assessment of error rates and uncertainty inherent in the estimation of this pool. Here, we use Monte Carlo analysis to propagate the error associated with the major sources of uncertainty present in the calculation of coarse wood carbon and nutrient (i.e., N, P, K, Ca, Mg, Na) pools. We also evaluate individual sources of error to identify the importance of each source of uncertainty in our estimates. We quantify sampling error by comparing the three most common field methods used to survey coarse wood (two transect methods and a whole-plot survey). We quantify the measurement error associated with length and diameter measurement, and technician error in species identification and decay class using plots surveyed by multiple technicians. We use previously published values of model error for the four most common methods of volume estimation: Smalian's, conical frustum, conic paraboloid, and average-of-ends. We also use previously published values for error in the collapse ratio (cross-sectional height/width) of decayed logs that serves as a surrogate for the volume remaining. We consider sampling error in chemical concentration and density for all decay classes, using distributions from both published and unpublished studies. Analytical uncertainty is calculated using standard reference plant material from the National Institute of Standards. Our results suggest that technician error in decay classification can have a large effect on uncertainty, since many of the error distributions included in the calculation (e.g. density, chemical concentration, volume-model selection, collapse ratio) are decay-class specific.

Studies in mid-infrared spectropolarimetry - II. An atlas of spectra

NASA Astrophysics Data System (ADS)

Smith, Craig H.; Wright, Christopher M.; Aitken, David K.; Roche, Patrick F.; Hough, James H.

2000-02-01

We present 8-13μm spectropolarimetry of 55 sources and 16-22μm spectropolarimetry of six of these. This represents a substantial fraction of star formation regions that can be observed in this way with current technology on 4-m class telescopes (i.e. brighter than about 20Jy at 10μm in a 4-arcsec beam). Most of the sources are embedded young stellar objects (YSOs), Hii regions containing sites of star formation or bipolar protoplanetary nebulae (PPN), although a few other sources (e.g. NGC 1068, MWC 349) are also included. The majority have oxygen-rich chemistry but there are three carbon-rich sources. Many of the oxygen-rich sources show deep silicate absorption overlying featureless or optically thin silicate emission. Absorptive polarization with polarization per optical depth (paτ)~=1-3 per cent is common, and many also show evidence for an emissive polarization component as well, although pure polarization in emission is rare. The observed ranges of paτ and pe are very similar, rather surprising in view of their origin from very different environments. Typically the absorptive polarization profiles are similar to the archetypal silicate polarization found in OMC1 BN, but an exception is AFGL 2591, which displays an additional narrow polarization feature at 11.2μm, which has been attributed to annealed silicates. Many of the intensity absorption spectra also show an inflection near 11.2μm, which might also be attributable to annealed silicates. The carbon-rich sources have nearly featureless polarizations in the 0.5-1per cent range, which we ascribe to dichroism in carbon-based grains; this is the first evidence that such grains can be aligned. In two of these sources the polarization appears to be caused by absorption by SiC. A few of the polarization spectra have no straightforward interpretation.

Tracking changes in the optical properties and molecular composition of dissolved organic matter during drinking water production.

PubMed

Lavonen, E E; Kothawala, D N; Tranvik, L J; Gonsior, M; Schmitt-Kopplin, P; Köhler, S J

2015-11-15

Absorbance, 3D fluorescence and ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) were used to explain patterns in the removal of chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) at the molecular level during drinking water production at four large drinking water treatment plants in Sweden. When dissolved organic carbon (DOC) removal was low, shifts in the dissolved organic matter (DOM) composition could not be detected with commonly used DOC-normalized parameters (e.g. specific UV254 absorbance - SUVA), but was clearly observed by using differential absorbance and fluorescence or ESI-FT-ICR-MS. In addition, we took a novel approach by identifying how optical parameters were correlated to the elemental composition of DOM by using rank correlation to connect optical properties to chemical formulas assigned to mass peaks from FT-ICR-MS analyses. Coagulation treatment selectively removed FDOM at longer emission wavelengths (450-600 nm), which significantly correlated with chemical formulas containing oxidized carbon (average carbon oxidation state ≥ 0), low hydrogen to carbon ratios (H/C: average ± SD = 0.83 ± 0.13), and abundant oxygen-containing functional groups (O/C = 0.62 ± 0.10). Slow sand filtration was less efficient in removing DOM, yet selectively targeted FDOM at shorter emission wavelengths (between 300 and 450 nm), which commonly represents algal rather than terrestrial sources. This shorter wavelength FDOM correlated with chemical formulas containing reduced carbon (average carbon oxidation state ≤ 0), with relatively few carbon-carbon double bonds (H/C = 1.32 ± 0.16) and less oxygen per carbon (O/C = 0.43 ± 0.10) than those removed during coagulation. By coupling optical approaches with FT-ICR-MS to characterize DOM, we were for the first time able to confirm the molecular composition of absorbing and fluorescing DOM selectively targeted during drinking water treatment. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Abiotic vs biological sources and fates of organic compounds in a low temperature continental serpentinizing system

NASA Astrophysics Data System (ADS)

Robinson, K.; Noble, S. M.; Shock, E.

2016-12-01

Serpentinization is likely the most common water-rock reaction in our solar system. During this process ultramafic silicates are hydrated, a calcium hydroxide solution is formed, and H2O is reduced to H2 coupled to the oxidation of Fe2+ to Fe3+. The resulting hyper-alkaline, reduced conditions generate thermodynamic drives for numerous carbon compound reactions, including the precipitation of various carbonate minerals and the reduction of inorganic carbonate to organic carbon. Testing the extent to which these thermodynamic drives lead to observable results led to the present study of the flow and transformations of carbon through the active continental serpentinizing system at the Samail Ophiolite in the Sultanate of Oman. Water samples were collected from shallow groundwater (representing system input), hyper-alkaline seeps (system output), boreholes (system intermediate), and surface fluid mixing zones, and analyzed for concentrations of dissolved inorganic carbon (DIC + δ13C), organic carbon (+ δ13C), formate, acetate, H2, methane (+ δ13C), ethane, and an accompanying suite of other geochemical solutes. These analyses indicate that the vast majority of DIC in these serpentinizing fluids precipitates in the subsurface as carbonate minerals; however, a significant amount of DIC is converted into organic acids and light hydrocarbons and expelled at the surface in hyper-alkaline seeps. Based on thermodynamic calculations, it seems most likely that formate last equilibrated with dolomite (CaMg[CO3]2) in the subsurface, acetate last equilibrated with calcite (CaCO3) near the surface, and methane and ethane last equilibrated in a distinct carbon-limited region of the subsurface. As for the fates of these compounds, energetic calculations reveal that a combination of oxidative, reductive, and fermentative metabolisms are thermodynamically favorable. Indeed, δ13C trends record microbial methane oxidation at the surface and cannot rule out methane as biologically sourced from the subsurface.

Isotopically zoned carbonate cements in Early Paleozoic sandstones of the Illinois Basin: δ18O and δ13C records of burial and fluid flow

NASA Astrophysics Data System (ADS)

Denny, Adam C.; Kozdon, Reinhard; Kitajima, Kouki; Valley, John W.

2017-11-01

SEM/SIMS imaging and analysis of δ18O and δ13C in sandstones from a transect through the Illinois Basin (USA) show systematic μm-scale isotopic zonation of up to 10‰ in both carbonate and quartz cements of the middle-Ordovician St. Peter and Cambrian Mt. Simon formations. Quartz δ18O values are broadly consistent with the model of Hyodo et al. (2014), wherein burial and heating in the Illinois Basin is recorded in systematically zoned quartz overgrowths. Observations of zoned dolomite/ankerite cements indicate that they preserve a more extended record of temperature and fluid compositions than quartz, including early diagenesis before or during shallow burial, and late carbonates formed after quartz overgrowths. Many carbonate cements show innermost dolomite with δ18O values (21-25‰ VSMOW) that are too low to have formed by deposition at low temperatures from ancient seawater (δ18O > - 3‰) and most likely reflect mixing with meteoric water. A sharp increase in Fe content is commonly observed in zoned carbonate cements to be associated with a drop in δ18O and an abrupt shift in δ13C to higher or lower values. These changes are interpreted to record the passage of hot metal-rich brines through sandstone aquifers, that was associated with Mississippi-Valley Type (MVT) Pb-Zn deposits (ca. 270 Ma) of the Upper Mississippi Valley. Local variability and individual trends in δ13C are likely controlled by the sources of carbon and the degree to which carbon is sourced from adjacent carbonate units or thermal maturation of organic matter. Quartz overgrowths in sandstones provide an excellent record of conditions during burial, heating, and pressure-solution, whereas carbonate cements in sandstones preserve a more-extended record including initial pre-burial conditions and punctuated fluid flow events.

Regulation of Nitrogen Metabolism by GATA Zinc Finger Transcription Factors in Yarrowia lipolytica

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

Pomraning, Kyle R.; Bredeweg, Erin L.; Baker, Scott E.

ABSTRACT Fungi accumulate lipids in a manner dependent on the quantity and quality of the nitrogen source on which they are growing. In the oleaginous yeastYarrowia lipolytica, growth on a complex source of nitrogen enables rapid growth and limited accumulation of neutral lipids, while growth on a simple nitrogen source promotes lipid accumulation in large lipid droplets. Here we examined the roles of nitrogen catabolite repression and its regulation by GATA zinc finger transcription factors on lipid metabolism inY. lipolytica. Deletion of the GATA transcription factor genesgzf3andgzf2resulted in nitrogen source-specific growth defects and greater accumulation of lipids when the cells weremore » growing on a simple nitrogen source. Deletion ofgzf1, which is most similar to activators of genes repressed by nitrogen catabolite repression in filamentous ascomycetes, did not affect growth on the nitrogen sources tested. We examined gene expression of wild-type and GATA transcription factor mutants on simple and complex nitrogen sources and found that expression of enzymes involved in malate metabolism, beta-oxidation, and ammonia utilization are strongly upregulated on a simple nitrogen source. Deletion ofgzf3results in overexpression of genes with GATAA sites in their promoters, suggesting that it acts as a repressor, whilegzf2is required for expression of ammonia utilization genes but does not grossly affect the transcription level of genes predicted to be controlled by nitrogen catabolite repression. Both GATA transcription factor mutants exhibit decreased expression of genes controlled by carbon catabolite repression via the repressormig1, including genes for beta-oxidation, highlighting the complex interplay between regulation of carbon, nitrogen, and lipid metabolism. IMPORTANCENitrogen source is commonly used to control lipid production in industrial fungi. Here we identified regulators of nitrogen catabolite repression in the oleaginous yeastY. lipolyticato determine how the nitrogen source regulates lipid metabolism. We show that disruption of both activators and repressors of nitrogen catabolite repression leads to increased lipid accumulation via activation of carbon catabolite repression through an as yet uncharacterized method.« less

Improving source identification of Atlanta aerosol using temperature resolved carbon fractions in positive matrix factorization

NASA Astrophysics Data System (ADS)

Kim, Eugene; Hopke, Philip K.; Edgerton, Eric S.

Daily integrated PM 2.5 (particulate matter ⩽2.5 μm in aerodynamic diameter) composition data including eight individual carbon fractions collected at the Jefferson Street monitoring site in Atlanta were analyzed with positive matrix factorization (PMF). Particulate carbon was analyzed using the thermal optical reflectance method that divides carbon into four organic carbon (OC), pyrolized organic carbon (OP), and three elemental carbon (EC) fractions. A total of 529 samples and 28 variables were measured between August 1998 and August 2000. PMF identified 11 sources in this study: sulfate-rich secondary aerosol I (50%), on-road diesel emissions (11%), nitrate-rich secondary aerosol (9%), wood smoke (7%), gasoline vehicle (6%), sulfate-rich secondary aerosol II (6%), metal processing (3%), airborne soil (3%), railroad traffic (3%), cement kiln/carbon-rich (2%), and bus maintenance facility/highway traffic (2%). Differences from previous studies using only the traditional OC and EC data (J. Air Waste Manag. Assoc. 53(2003a)731; Atmos Environ. (2003b)) include four traffic-related combustion sources (gasoline vehicle, on-road diesel, railroad, and bus maintenance facility) containing carbon fractions whose abundances were different between the various sources. This study indicates that the temperature resolved fractional carbon data can be utilized to enhance source apportionment study, especially with respect to the separation of diesel emissions from gasoline vehicle sources. Conditional probability functions using surface wind data and identified source contributions aid the identifications of local point sources.

40 CFR 458.45 - Standards of performance for new sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp... paragraph, which may be discharged from the carbon black lamp process by a new source subject to the...

Dual-Carbon sources fuel the OCS deep-reef Community, a stable isotope investigation

USGS Publications Warehouse

Sulak, Kenneth J.; Berg, J.; Randall, Michael T.; Dennis, George D.; Brooks, R.A.

2008-01-01

The hypothesis that phytoplankton is the sole carbon source for the OCS deep-reef community (>60 m) was tested. Trophic structure for NE Gulf of Mexico deep reefs was analyzed via carbon and nitrogen stable isotopes. Carbon signatures for 114 entities (carbon sources, sediment, fishes, and invertebrates) supported surface phytoplankton as the primary fuel for the deep reef. However, a second carbon source, the macroalga Sargassum, with its epiphytic macroalgal associate, Cladophora liniformis, was also identified. Macroalgal carbon signatures were detected among 23 consumer entities. Most notably, macroalgae contributed 45 % of total carbon to the 13C isotopic spectrum of the particulate-feeding reef-crest gorgonian Nicella. The discontinuous spatial distribution of some sessile deep-reef invertebrates utilizing pelagic macroalgal carbon may be trophically tied to the contagious distribution of Sargassum biomass along major ocean surface features.

Functionalized Natural Carbon-Supported Nanoparticles as Excellent Catalysts for Hydrocarbon Production.

PubMed

Sun, Jian; Guo, Lisheng; Ma, Qingxiang; Gao, Xinhua; Yamane, Noriyuki; Xu, Hengyong; Tsubaki, Noritatsu

2017-02-01

We report a one-pot and eco-friendly synthesis of carbon-supported cobalt nanoparticles, achieved by carbonization of waste biomass (rice bran) with a cobalt source. The functionalized biomass provides carbon microspheres as excellent catalyst support, forming a unique interface between hydrophobic and hydrophilic groups. The latter, involving hydroxyl and amino groups, can catch much more active cobalt nanoparticles on surface for Fischer-Tropsch synthesis than chemical carbon. The loading amount of cobalt on the final catalyst is much higher than that prepared with a chemical carbon source, such as glucose. The proposed concept of using a functionalized natural carbon source shows great potential compared with conventional carbon sources, and will be meaningful for other fields concerning carbon support, such as heterogeneous catalysis or electrochemical fields. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microbial co-occurrence patterns in deep Precambrian bedrock fracture fluids

NASA Astrophysics Data System (ADS)

Purkamo, Lotta; Bomberg, Malin; Kietäväinen, Riikka; Salavirta, Heikki; Nyyssönen, Mari; Nuppunen-Puputti, Maija; Ahonen, Lasse; Kukkonen, Ilmo; Itävaara, Merja

2016-05-01

The bacterial and archaeal community composition and the possible carbon assimilation processes and energy sources of microbial communities in oligotrophic, deep, crystalline bedrock fractures is yet to be resolved. In this study, intrinsic microbial communities from groundwater of six fracture zones from 180 to 2300 m depths in Outokumpu bedrock were characterized using high-throughput amplicon sequencing and metagenomic prediction. Comamonadaceae-, Anaerobrancaceae- and Pseudomonadaceae-related operational taxonomic units (OTUs) form the core community in deep crystalline bedrock fractures in Outokumpu. Archaeal communities were mainly composed of Methanobacteriaceae-affiliating OTUs. The predicted bacterial metagenomes showed that pathways involved in fatty acid and amino sugar metabolism were common. In addition, relative abundance of genes coding the enzymes of autotrophic carbon fixation pathways in predicted metagenomes was low. This indicates that heterotrophic carbon assimilation is more important for microbial communities of the fracture zones. Network analysis based on co-occurrence of OTUs revealed possible "keystone" genera of the microbial communities belonging to Burkholderiales and Clostridiales. Bacterial communities in fractures resemble those found in oligotrophic, hydrogen-enriched environments. Serpentinization reactions of ophiolitic rocks in Outokumpu assemblage may provide a source of energy and organic carbon compounds for the microbial communities in the fractures. Sulfate reducers and methanogens form a minority of the total microbial communities, but OTUs forming these minor groups are similar to those found in other deep Precambrian terrestrial bedrock environments.

The keystone species of Precambrian deep bedrock biosphere belong to Burkholderiales and Clostridiales

NASA Astrophysics Data System (ADS)

Purkamo, L.; Bomberg, M.; Kietäväinen, R.; Salavirta, H.; Nyyssönen, M.; Nuppunen-Puputti, M.; Ahonen, L.; Kukkonen, I.; Itävaara, M.

2015-11-01

The bacterial and archaeal community composition and the possible carbon assimilation processes and energy sources of microbial communities in oligotrophic, deep, crystalline bedrock fractures is yet to be resolved. In this study, intrinsic microbial communities from six fracture zones from 180-2300 m depths in Outokumpu bedrock were characterized using high-throughput amplicon sequencing and metagenomic prediction. Comamonadaceae-, Anaerobrancaceae- and Pseudomonadaceae-related OTUs form the core community in deep crystalline bedrock fractures in Outokumpu. Archaeal communities were mainly composed of Methanobacteraceae-affiliating OTUs. The predicted bacterial metagenomes showed that pathways involved in fatty acid and amino sugar metabolism were common. In addition, relative abundance of genes coding the enzymes of autotrophic carbon fixation pathways in predicted metagenomes was low. This indicates that heterotrophic carbon assimilation is more important for microbial communities of the fracture zones. Network analysis based on co-occurrence of OTUs revealed the keystone genera of the microbial communities belonging to Burkholderiales and Clostridiales. Bacterial communities in fractures resemble those found from oligotrophic, hydrogen-enriched environments. Serpentinization reactions of ophiolitic rocks in Outokumpu assemblage may provide a source of energy and organic carbon compounds for the microbial communities in the fractures. Sulfate reducers and methanogens form a minority of the total microbial communities, but OTUs forming these minor groups are similar to those found from other deep Precambrian terrestrial bedrock environments.

The determination of the energy values and the composition analysis of M-16 rifle black powders

NASA Astrophysics Data System (ADS)

Satee, R.; Dararutana, P.; Phutdhawong, W.

2017-09-01

The determination of the energy values, specifically the heat of combustion of various M-16 black powders was the important part of the bullet efficiency investigations. The calorimetric bomb is commonly used for these determinations. Four M-16 black powders from the different sources were used as samples for this research. It was found that, after using calorimetric bomb technique, the gross heating value in Joules/g of sample S1-S4 were 10,647, 10,416, 5,281 and 3,878 respectively. The chemical compositions of carbon (C), hydrogen (H), nitrogen (N) and sulfer (S) have also been determined. The results indicated that carbon and nitrogen compositions of sample S1 shown the highest values and provided little differences with sample S2 while sample S3 and S4 shown the lowest carbon and nitrogen percentage composition. The hydrogen composition of all samples was equally valued, however, only sample 3 and 4 displayed sulfur values while no sulfur values were detected from sample 1 and 2. From these results, the heat values and chemical composition of M-16 black powders were characterized their sources and the energy values might be estimated from the amount of carbon and nitrogen in the black powders. Thus, it would be possible to use this determination analysis in the forensic investigation.

Development of a Design Tool for Planning Aqueous Amendment Injection Systems

DTIC Science & Technology

2008-06-01

BIOREMresources.asp) • “Protocol for Enhanced In Situ Bioremediation Using Emulsified Edible Oil” – (search for title at http://docs.serdp-estcp.org...index.cfm) • “Protocol for In Situ Bioremediation of Chlorinated Solvents Using Edible Oil” (http://www.afcee.brooks.af.mil/products/techtrans...and acetate by common subsurface microorganisms . The H2 and acetate are then used as a carbon and energy source for anaerobic biodegradation of the

Assessment of Contribution of Contemporary Carbon Sources to Size-Fractionated Particulate Matter and Time-Resolved Bulk Particulate Matter Using the Measurement of Radiocarbon

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

Hwang, H M; Young, T M; Buchholz, B A

2009-04-16

This study was motivated by a desire to improve understanding of the sources contributing to the carbon that is an important component of airborne particulate matter (PM). The ultimate goal of this project was to lay a ground work for future tools that might be easily implemented with archived or routinely collected samples. A key feature of this study was application of radiocarbon measurement that can be interpreted to indicate the relative contributions from fossil and non-fossil carbon sources of atmospheric PM. Size-resolved PM and time-resolved PM{sub 10} collected from a site in Sacramento, CA in November 2007 (Phase I)more » and March 2008 (Phase II) were analyzed for radiocarbon and source markers such as levoglucosan, cholesterol, and elemental carbon. Radiocarbon data indicates that the contributions of non-fossil carbon sources were much greater than that from fossil carbon sources in all samples. Radiocarbon and source marker measurements confirm that a greater contribution of non-fossil carbon sources in Phase I samples was highly likely due to residential wood combustion. The present study proves that measurement of radiocarbon and source markers can be readily applied to archived or routinely collected samples for better characterization of PM sources. More accurate source apportionment will support ARB in developing more efficient control strategies.« less

The use of fermentation liquid of wastewater primary sedimentation sludge as supplemental carbon source for denitrification based on enhanced anaerobic fermentation.

PubMed

Liu, Feng; Tian, Yu; Ding, Yi; Li, Zhipeng

2016-11-01

Wastewater primary sedimentation sludge was prepared into fermentation liquid as denitrification carbon source, and the main components of fermentation liquid was short-chain volatile fatty acids. Meanwhile, the acetic acid and propionic acid respectively accounted for about 29.36% and 26.56% in short-chain volatile fatty acids. The performance of fermentation liquid, methanol, acetic acid, propionic acid and glucose used as sole carbon source were compared. It was found that the denitrification rate with fermentation liquid as carbon source was 0.17mgNO3(-)-N/mg mixed liquor suspended solid d, faster than that with methanol, acetic acid, and propionic acid as sole carbon source, and lower than that with glucose as sole carbon source. For the fermentation liquid as carbon source, the transient accumulation of nitrite was insignificantly under different initial total nitrogen concentration. Therefore, the use of fermentation liquid for nitrogen removal could improve denitrification rate, and reduce nitrite accumulation in denitrification process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization and Genomic Analysis of a Highly Efficient Dibutyl Phthalate-Degrading Bacterium Gordonia sp. Strain QH-12.

PubMed

Jin, Decai; Kong, Xiao; Liu, Huijun; Wang, Xinxin; Deng, Ye; Jia, Minghong; Yu, Xiangyang

2016-06-25

A bacterial strain QH-12 isolated from activated sludge was identified as Gordonia sp. based on analysis of 16S rRNA gene sequence and was found to be capable of utilizing dibutyl phthalate (DBP) and other common phthalate esters (PAEs) as the sole carbon and energy source. The degradation kinetics of DBP under different concentrations by the strain QH-12 fit well with the modified Gompertz model (R² > 0.98). However, strain QH-12 could not utilize the major intermediate product phthalate (phthalic acid; PA) as the sole carbon and energy source, and only a little amount of PA was detected. The QH-12 genome analysis revealed the presence of putative hydrolase/esterase genes involved in PAEs-degradation but no phthalic acid catabolic gene cluster was found, suggesting that a novel degradation pathway of PAEs was present in Gordonia sp. QH-12. This information will be valuable for obtaining a more holistic understanding on diverse genetic mechanisms of PAEs-degrading Gordonia sp. strains.

Calcio-carbonatite melts and metasomatism in the mantle beneath Mt. Vulture (Southern Italy)

NASA Astrophysics Data System (ADS)

Rosatelli, Gianluigi; Wall, Frances; Stoppa, Francesco

2007-12-01

At Mt. Vulture volcano (Basilicata, Italy) calcite globules (5-150 μm) are hosted by silicate glass pools or veins cross-cutting amphibole-bearing, or more common spinel-bearing mantle xenoliths and xenocrysts. The carbonate globules are rounded or elongated and are composed of a mosaic of 2-20 μm crystals, with varying optical orientation. These features are consistent with formation from a quenched calciocarbonatite melt. Where in contact with carbonate amphibole has reacted to form fassaitic pyroxene. Some of these globules contain liquid/gaseous CO 2 bubbles and sulphide inclusions, and are pierced by quench microphenocrysts of silicate phases. The carbonate composition varies from calcite to Mg-calcite (3.8-5.0 wt.% MgO) both within the carbonate globules and from globule to globule. Trace element contents of the carbonate, determined by LAICPMS, are similar to those of carbonatites worldwide including ΣREE up to 123 ppm. The Sr-Nd isotope ratios of the xenolith carbonate are similar to the extrusive carbonatite and silicate rocks of Mt. Vulture testifying to derivation from the same mantle source. Formation of immiscibile silicate-carbonatite liquids within mantle xenoliths occurred via disequilibrium immiscibility during their exhumation.

Constraints on primary and secondary particulate carbon sources using chemical tracer and 14C methods during CalNex-Bakersfield

NASA Astrophysics Data System (ADS)

Sheesley, Rebecca J.; Nallathamby, Punith Dev; Surratt, Jason D.; Lee, Anita; Lewandowski, Michael; Offenberg, John H.; Jaoui, Mohammed; Kleindienst, Tadeusz E.

2017-10-01

The present study investigates primary and secondary sources of organic carbon for Bakersfield, CA, USA as part of the 2010 CalNex study. The method used here involves integrated sampling that is designed to allow for detailed and specific chemical analysis of particulate matter (PM) in the Bakersfield airshed. To achieve this objective, filter samples were taken during thirty-four 23-hr periods between 19 May and 26 June 2010 and analyzed for organic tracers by gas chromatography - mass spectrometry (GC-MS). Contributions to organic carbon (OC) were determined by two organic tracer-based techniques: primary OC by chemical mass balance and secondary OC by a mass fraction method. Radiocarbon (14C) measurements of the total organic carbon were also made to determine the split between the modern and fossil carbon and thereby constrain unknown sources of OC not accounted for by either tracer-based attribution technique. From the analysis, OC contributions from four primary sources and four secondary sources were determined, which comprised three sources of modern carbon and five sources of fossil carbon. The major primary sources of OC were from vegetative detritus (9.8%), diesel (2.3%), gasoline (<1.0%), and lubricating oil impacted motor vehicle exhaust (30%); measured secondary sources resulted from isoprene (1.5%), α-pinene (<1.0%), toluene (<1.0%), and naphthalene (<1.0%, as an upper limit) contributions. The average observed organic carbon (OC) was 6.42 ± 2.33 μgC m-3. The 14C derived apportionment indicated that modern and fossil components were nearly equivalent on average; however, the fossil contribution ranged from 32 to 66% over the five week campaign. With the fossil primary and secondary sources aggregated, only 25% of the fossil organic carbon could not be attributed. Whereas, nearly 80% of the modern carbon could not be attributed to primary and secondary sources accessible to this analysis, which included tracers of biomass burning, vegetative detritus and secondary biogenic carbon. The results of the current study contributes source-based evaluation of the carbonaceous aerosol at CalNex Bakersfield.

Constraints on primary and secondary particulate carbon sources using chemical tracer and 14C methods during CalNex-Bakersfield

PubMed Central

Sheesley, Rebecca J.; Nallathamby, Punith Dev; Surratt, Jason D.; Lee, Anita; Lewandowski, Michael; Offenberg, John H.; Jaoui, Mohammed; Kleindienst, Tadeusz E.

2018-01-01

The present study investigates primary and secondary sources of organic carbon for Bakersfield, CA, USA as part of the 2010 CalNex study. The method used here involves integrated sampling that is designed to allow for detailed and specific chemical analysis of particulate matter (PM) in the Bakersfield airshed. To achieve this objective, filter samples were taken during thirty-four 23-hr periods between 19 May and 26 June 2010 and analyzed for organic tracers by gas chromatography – mass spectrometry (GC-MS). Contributions to organic carbon (OC) were determined by two organic tracer-based techniques: primary OC by chemical mass balance and secondary OC by a mass fraction method. Radiocarbon (14C) measurements of the total organic carbon were also made to determine the split between the modern and fossil carbon and thereby constrain unknown sources of OC not accounted for by either tracer-based attribution technique. From the analysis, OC contributions from four primary sources and four secondary sources were determined, which comprised three sources of modern carbon and five sources of fossil carbon. The major primary sources of OC were from vegetative detritus (9.8%), diesel (2.3%), gasoline (<1.0%), and lubricating oil impacted motor vehicle exhaust (30%); measured secondary sources resulted from isoprene (1.5%), α-pinene (<1.0%), toluene (<1.0%), and naphthalene (<1.0%, as an upper limit) contributions. The average observed organic carbon (OC) was 6.42 ± 2.33 μgC m−3. The 14C derived apportionment indicated that modern and fossil components were nearly equivalent on average; however, the fossil contribution ranged from 32-66% over the five week campaign. With the fossil primary and secondary sources aggregated, only 25% of the fossil organic carbon could not be attributed. Whereas, nearly 80% of the modern carbon could not be attributed to primary and secondary sources accessible to this analysis, which included tracers of biomass burning, vegetative detritus and secondary biogenic carbon. The results of the current study contributes source-based evaluation of the carbonaceous aerosol at CalNex Bakersfield. PMID:29681757

Source apportionments of ambient fine particulate matter in Israeli, Jordanian, and Palestinian cities.

PubMed

Heo, Jongbae; Wu, Bo; Abdeen, Ziad; Qasrawi, Radwan; Sarnat, Jeremy A; Sharf, Geula; Shpund, Kobby; Schauer, James J

2017-06-01

This manuscript evaluates spatial and temporal variations of source contributions to ambient fine particulate matter (PM 2.5 ) in Israeli, Jordanian, and Palestinian cities. Twenty-four hour integrated PM 2.5 samples were collected every six days over a 1-year period (January to December 2007) in four cities in Israel (West Jerusalem, Eilat, Tel Aviv, and Haifa), four cities in Jordan (Amman, Aqaba, Rahma, and Zarka), and three cities in Palestine (Nablus, East Jerusalem, and Hebron). The PM 2.5 samples were analyzed for major chemical components, including organic carbon and elemental carbon, ions, and metals, and the results were used in a positive matrix factorization (PMF) model to estimate source contributions to PM 2.5 mass. Nine sources, including secondary sulfate, secondary nitrate, mobile, industrial lead sources, dust, construction dust, biomass burning, fuel oil combustion and sea salt, were identified across the sampling sites. Secondary sulfate was the dominant source, contributing 35% of the total PM 2.5 mass, and it showed relatively homogeneous temporal trends of daily source contribution in the study area. Mobile sources were found to be the second greatest contributor to PM 2.5 mass in the large metropolitan cities, such as Tel Aviv, Hebron, and West and East Jerusalem. Other sources (i.e. industrial lead sources, construction dust, and fuel oil combustion) were closely related to local emissions within individual cities. This study demonstrates how international cooperation can facilitate air pollution studies that address regional air pollution issues and the incremental differences across cities in a common airshed. It also provides a model to study air pollution in regions with limited air quality monitoring capacity that have persistent and emerging air quality problems, such as Africa, South Asia and Central America. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Aulich, Ted R [Grand Forks, ND; Olson, Edwin S [Grand Forks, ND; Jiang, Junhua [Grand Forks, ND

2012-04-10

The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia, at low temperature and pressure, preferably at ambient temperature and pressure, utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen or hydrogen equivalent. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source or a hydrogen equivalent such as carbon monoxide or a mixture of carbon monoxide and hydrogen at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be aqueous, non-aqueous, or solid.

Adventitious Carbon on Primary Sample Containment Metal Surfaces

NASA Technical Reports Server (NTRS)

Calaway, M. J.; Fries, M. D.

2015-01-01

Future missions that return astromaterials with trace carbonaceous signatures will require strict protocols for reducing and controlling terrestrial carbon contamination. Adventitious carbon (AC) on primary sample containers and related hardware is an important source of that contamination. AC is a thin film layer or heterogeneously dispersed carbonaceous material that naturally accrues from the environment on the surface of atmospheric exposed metal parts. To test basic cleaning techniques for AC control, metal surfaces commonly used for flight hardware and curating astromaterials at JSC were cleaned using a basic cleaning protocol and characterized for AC residue. Two electropolished stainless steel 316L (SS- 316L) and two Al 6061 (Al-6061) test coupons (2.5 cm diameter by 0.3 cm thick) were subjected to precision cleaning in the JSC Genesis ISO class 4 cleanroom Precision Cleaning Laboratory. Afterwards, the samples were analyzed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.

Molecular basis of autotrophic vs mixotrophic growth in Chlorella sorokiniana.

PubMed

Cecchin, M; Benfatto, S; Griggio, F; Mori, A; Cazzaniga, S; Vitulo, N; Delledonne, M; Ballottari, M

2018-04-24

In this work, we investigated the molecular basis of autotrophic vs. mixotrophic growth of Chlorella sorokiniana, one of the most productive microalgae species with high potential to produce biofuels, food and high value compounds. To increase biomass accumulation, photosynthetic microalgae are commonly cultivated in mixotrophic conditions, adding reduced carbon sources to the growth media. In the case of C. sorokiniana, the presence of acetate enhanced biomass, proteins, lipids and starch productivity when compared to autotrophic conditions. Despite decreased chlorophyll content, photosynthetic properties were essentially unaffected while differential gene expression profile revealed transcriptional regulation of several genes mainly involved in control of carbon flux. Interestingly, acetate assimilation caused upregulation of phosphoenolpyruvate carboxylase enzyme, enabling potential recovery of carbon atoms lost by acetate oxidation. The obtained results allowed to associate the increased productivity observed in mixotrophy in C. sorokiniana with a different gene regulation leading to a fine regulation of cell metabolism.

Variation in nutrient-acquisition patterns by mycorrhizal fungi of rare and common orchids explains diversification in a global biodiversity hotspot.

PubMed

Nurfadilah, Siti; Swarts, Nigel D; Dixon, Kingsley W; Lambers, Hans; Merritt, David J

2013-06-01

Many terrestrial orchids have an obligate requirement for mycorrhizal associations to provide nutritional support from germination to establishment. This study will investigate the ability of orchid mycorrhizal fungi (OMF) to utilize a variety of nutrient sources in the nutrient-impoverished (low organic) soils of the Southwest Australian Floristic Region (SWAFR) in order to effectively compete, survive and sustain the orchid host. Mycorrhizal fungi representing key OMF genera were isolated from three common and widespread species: Pterostylis recurva, Caladenia flava and Diuris corymbosa, and one rare and restricted species: Drakaea elastica. The accessibility of specific nutrients was assessed by comparing growth including dry biomass of OMF in vitro on basal CN MMN liquid media. Each of the OMF accessed and effectively utilized a wide variety of nutrient compounds, including carbon (C) sources, inorganic and organic nitrogen (N) and inorganic and organic phosphorus (P). The nutrient compounds utilized varied between the genera of OMF, most notably sources of N. These results suggest that OMF can differentiate between niches (micro-niche specialization) in a constrained, highly resource-limited environment such as the SWAFR. Phosphorus is the most limited macronutrient in SWAFR soils and the ability to access phytate by OMF indicates a characterizing functional capacity of OMF from the SWAFR. Furthermore, compared with OMF isolated from the rare D. elastica, OMF associating with the common P. recurva produced far greater biomass over a wider variety of nutritional sources. This suggests a broader tolerance for habitat variation providing more opportunities for the common orchid for recruitment and establishment at a site.

Spatiotemporal Heterogeneity of Dissolved Organic Carbon in Waters and Soils in a Snow-dominated Headwater Catchment: Investigations at Reynolds Creek Critical Zone Observatory, Owyhee County, Idaho

NASA Astrophysics Data System (ADS)

Radke, A. G.; Godsey, S.; Lohse, K. A.; Huber, D. P.; Patton, N. R.; Holbrook, S.

2017-12-01

The non-uniform distribution of precipitation in snowmelt-driven systems—the result of blowing and drifting snow—is a primary driver of spatial heterogeneity in vegetative communities and soil development. Snowdrifts may increase bedrock weathering below them, creating deeper soils and the potential for greater fracture flow. These snowdrift areas are also commonly more productive than the snow-starved, scoured areas where wind has removed snow. Warming-induced changes in the fraction of precipitation falling as snow, and therefore subject to drifting, may significantly affect carbon dynamics on multiple timescales. The focus of this study is to understand the coupled hydrological and carbon dynamics in a heterogeneous, drift-dominated watershed. We seek to determine the paths of soil water and groundwater in a small headwater catchment (Reynolds Mountain East, Reynolds Creek Critical Zone Observatory, Idaho, USA). Additionally, we anticipate quantifying the flux of dissolved organic carbon through these paths, and relate this to zones of greater vegetative productivity. We deduce likely flowpaths through a combination of soil water, groundwater, and precipitation characterization. Along a transect running from a snowdrift to the stream, we measure hydrometric and hydrochemical signatures of flow throughout the snowmelt period and summer. We then use end-member-mixing analysis to interpret flowpaths in light of inferred subsurface structure derived from drilling and electrical resistance tomography transects. Preliminary results from soil moisture sensors suggest that increased bedrock weathering creates pathways by which snowmelt bypasses portions of the soil, further increasing landscape heterogeneity. Further analysis will identify seasonal changes in carbon sourcing for this watershed, but initial indications are that spring streamwater is sourced primarily from soil water, with close associations between soil carbon and DOC.

Carbonaceous and inorganic aerosols over a sub-urban site in peninsular India: Temporal variability and source characteristics

NASA Astrophysics Data System (ADS)

Aswini, A. R.; Hegde, Prashant; Nair, Prabha R.

2018-01-01

PM10 aerosol samples collected from a sub-urban site in Coimbatore during pre-monsoon, monsoon, post-monsoon and winter from 2014 to 2016 showed a large variability from 7.6 to 89 μg m- 3 with an annual average of 41 ± 21 μg m- 3 (N = 69). High abundance of PM10 and other components were recorded during winter and lowest during monsoon period. Total carbonaceous aerosols and water soluble ionic species contributed to 31% and 45% of PM10 mass respectively. SO42 - was the most abundant species (average 9.8 ± 4.8 μg m- 3) and constituted for 24% of total mass. Organic Carbon (OC) was the next most abundant species ranging from 1 to 16 μg m- 3 with an average of 7 ± 3.6 μg m- 3 accounting for 17% of PM10 mass concentration. POC (primary organic carbon) and SOC (secondary organic carbon) accounted for 56% and 44% of OC respectively. A major portion of OC ( 60%) was found to be water soluble. The correlation between OC and EC (elemental carbon) was found to be higher for night-time compared to daytime suggesting their origin from common sources during night-time. K+ was found to be strongly correlated with OC during night-time. WSOC showed good correlation with POC and K+ which was high especially during night-time. WSON (water soluble organic nitrogen) accounted for 34% of water soluble total nitrogen (WSTN). HCO3- exhibited significant positive correlation with Ca2 + during daytime indicating their crustal origin. The observations suggest that the region is influenced by biomass burning sources, however during day-time, secondary production and terrestrial sources (due to high temperature and wind) significantly influence the atmospheric aerosols over this region.

Polyhydroxyalkanoates (PHA) production using wastewater as carbon source and activated sludge as microorganisms.

PubMed

Yan, S; Tyagi, R D; Surampalli, R Y

2006-01-01

Activated sludge from different full-scale wastewater treatment plants (municipal, pulp and paper industry, starch manufacturing and cheese manufacturing wastewaters) was used as a source of microorganisms to produce biodegradable plastics in shake flask experiments. Acetate, glucose and different wastewaters were used as carbon sources. Pulp and paper wastewater sludge was found to accumulate maximum concentration (43% of dry weight of suspended solids) of polyhydroxy alkanoates (PHA) with acetate as carbon source. Among the different wastewaters tested as a source of carbon, pulp and paper industry and starch industry wastewaters were found to be the best source of carbon while employing pulp and paper activated sludge for maximum accumulation of PHA. High concentration of volatile fatty acids in these wastewaters was the probable reason.

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Jiang, Junhua; Aulich, Ted R; Ignatchenko, Alexey V

2015-04-14

Methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia are disclosed. Embodiments include (1) ammonium nitrate produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source: (3) ammonia produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source or a hydrogen equivalent such as carbon monoxide or a mixture of carbon monoxide and hydrogen at the anode; and (4) urea-ammonium nitrate produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source.

Measurement of carbon capture efficiency and stored carbon leakage

DOEpatents

Keeling, Ralph F.; Dubey, Manvendra K.

2013-01-29

Data representative of a measured carbon dioxide (CO.sub.2) concentration and of a measured oxygen (O.sub.2) concentration at a measurement location can be used to determine whether the measured carbon dioxide concentration at the measurement location is elevated relative to a baseline carbon dioxide concentration due to escape of carbon dioxide from a source associated with a carbon capture and storage process. Optionally, the data can be used to quantify a carbon dioxide concentration increase at the first location that is attributable to escape of carbon dioxide from the source and to calculate a rate of escape of carbon dioxide from the source by executing a model of gas-phase transport using at least the first carbon dioxide concentration increase. Related systems, methods, and articles of manufacture are also described.

Ozone-induced changes in natural organic matter (NOM) structure

USGS Publications Warehouse

Westerhoff, P.; Debroux, J.; Aiken, G.; Amy, G.

1999-01-01

Hydrophobic organic acids (combined humic and fulvic acids), obtained from an Antarctic Lake with predominantly microbially derived organic carbon sources and two US fiver systems with terrestrial organic carbon sources, were ozonated. Several analyses, including 13C-NMR, UV absorbance, fluorescence, hydrophobic/transphilic classification, and potentiometric titrations, were performed before and after ozonation. Ozonation reduced aromatic carbon content, selectively reducing phenolic carbon content. Ozonation of the samples resulted in increased aliphatic, carboxyl, plus acetal and ketal anomeric carbon content and shifted towards less hydrophobic compounds.Hydrophobic organic acids (combined humic and fulvic acids), obtained from an Antarctic Lake with predominantly microbially derived organic carbon sources and two US river systems with terrestrial organic carbon sources, were ozonated. Several analyses, including 13C-NMR, UV absorbance, fluorescence, hydrophobic/transphilic classification, and potentiometric titrations, were performed before and after ozonation. Ozonation reduced aromatic carbon content, selectively reducing phenolic carbon content. Ozonation of the samples resulted in increased aliphatic, carboxyl, plus acetal and ketal anomeric carbon content and shifted towards less hydrophobic compounds.

Growth of wildtype and mutant E. coli strains in minimal media for optimal production of nucleic acids for preparing labeled nucleotides

PubMed Central

Thakur, Chandar S.; Brown, Margaret E.; Sama, Jacob N.; Jackson, Melantha E.

2010-01-01

Since RNAs lie at the center of most cellular processes, there is a need for synthesizing large amounts of RNAs made from stable isotope-labeled nucleotides to advance the study of their structure and dynamics by nuclear magnetic resonance (NMR) spectroscopy. A particularly effective means of obtaining labeled nucleotides is to harvest these nucleotides from bacteria grown in defined minimal media supplemented with 15NH4Cl and various carbon sources. Given the high cost of carbon precursors required for labeling nucleic acids for NMR studies, it becomes important to evaluate the optimal growth for commonly used strains under standard minimal media conditions. Such information is lacking. In this study, we characterize the growth for Escherichia coli strains K12, K10zwf, and DL323 in three minimal media with isotopic-labeled carbon sources of acetate, glycerol, and glycerol combined with formate. Of the three media, the LeMaster-Richards and the Studier media outperform the commonly used M9 media and both support optimal growth of E. coli for the production of nucleotides. However, the growth of all three E. coli strains in acetate is reduced almost twofold compared to growth in glycerol. Analysis of the metabolic pathway and previous gene array studies help to explain this differential growth in glycerol and acetate. These studies should benefit efforts to make selective 13C-15N isotopic-labeled nucleotides for synthesizing biologically important RNAs. Electronic supplementary material The online version of this article (doi:10.1007/s00253-010-2813-y) contains supplementary material, which is available to authorized users. PMID:20730533

Using liquid waste streams as the moisture source during the hydrothermal carbonization of municipal solid wastes.

PubMed

Li, Liang; Hale, McKenzie; Olsen, Petra; Berge, Nicole D

2014-11-01

Hydrothermal carbonization (HTC) is a thermal conversion process that can be an environmentally beneficial approach for the conversion of municipal solid wastes to value-added products. The influence of using activated sludge and landfill leachate as initial moisture sources during the carbonization of paper, food waste and yard waste over time at 250°C was evaluated. Results from batch experiments indicate that the use of activated sludge and landfill leachate are acceptable alternative supplemental liquid sources, ultimately imparting minimal impact on carbonization product characteristics and yields. Regression results indicate that the initial carbon content of the feedstock is more influential than any of the characteristics of the initial liquid source and is statistically significant when describing the relationship associated with all evaluated carbonization products. Initial liquid-phase characteristics are only statistically significant when describing the solids energy content and the mass of carbon in the gas-phase. The use of these alternative liquid sources has the potential to greatly increase the sustainability of the carbonization process. A life cycle assessment is required to quantify the benefits associated with using these alternative liquid sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mercury and organic carbon dynamics during runoff episodes from a northeastern USA watershed

USGS Publications Warehouse

Schuster, P.F.; Shanley, J.B.; Marvin-DiPasquale, M.; Reddy, M.M.; Aiken, G.R.; Roth, D.A.; Taylor, Howard E.; Krabbenhoft, D.P.; DeWild, J.F.

2008-01-01

Mercury and organic carbon concentrations vary dynamically in streamwater at the Sleepers River Research Watershed in Vermont, USA. Total mercury (THg) concentrations ranged from 0.53 to 93.8 ng/L during a 3-year period of study. The highest mercury (Hg) concentrations occurred slightly before peak flows and were associated with the highest organic carbon (OC) concentrations. Dissolved Hg (DHg) was the dominant form in the upland catchments; particulate Hg (PHg) dominated in the lowland catchments. The concentration of hydrophobic acid (HPOA), the major component of dissolved organic carbon (DOC), explained 41-98% of the variability of DHg concentration while DOC flux explained 68-85% of the variability in DHg flux, indicating both quality and quantity of the DOC substantially influenced the transport and fate of DHg. Particulate organic carbon (POC) concentrations explained 50% of the PHg variability, indicating that POC is an important transport mechanism for PHg. Despite available sources of DHg and wetlands in the upland catchments, dissolved methylmercury (DmeHg) concentrations in streamwaters were below detection limit (0.04 ng/L). PHg and particulate methylmercury (PmeHg) had a strong positive correlation (r 2 = 0.84, p < 0.0001), suggesting a common source; likely in-stream or near-stream POC eroded or re-suspended during spring snowmelt and summer storms. Ratios of PmeHg to THg were low and fairly constant despite an apparent higher methylmercury (meHg) production potential in the summer. Methylmercury production in soils and stream sediments was below detection during snowmelt in April and highest in stream sediments (compared to forest and wetland soils) sampled in July. Using the watershed approach, the correlation of the percent of wetland cover to TmeHg concentrations in streamwater indicates that poorly drained wetland soils are a source of meHg and the relatively high concentrations found in stream surface sediments in July indicate these zones are a meHg sink. ?? 2007 Springer Science+Business Media B.V.

Improved Nitrogen Removal Effect In Continuous Flow A2/O Process Using Typical Extra Carbon Source

NASA Astrophysics Data System (ADS)

Wu, Haiyan; Gao, Junyan; Yang, Dianhai; Zhou, Qi; Cai, Bijing

2010-11-01

In order to provide a basis for optimal selection of carbon source, three typical external carbon sources (i.e. methanol, sodium acetate and leachate) were applied to examine nitrogen removal efficiency of continuous flow A2/O system with the influent from the effluent of grit chamber in the second Kunming wastewater treatment plant. The best dosage was determined, and the specific nitrogen removal rate and carbon consumption rate were calculated with regard to individual external carbon source in A2/O system. Economy and technology analysis was also conducted to select the suitable carbon source with a low operation cost. Experimental results showed that the external typical carbon source caused a remarkable enhancement of system nitrate degradation ability. In comparison with the blank test, the average TN and NH3-N removal efficiency of system with different dosing quantities of external carbon source was improved by 15.2% and 34.2%, respectively. The optimal dosage of methanol, sodium acetate and leachate was respectively up to 30 mg/L, 40 mg/L and 100 mg COD/L in terms of a high nitrogen degradation effect. The highest removal efficiency of COD, TN and NH3-N reached respectively 92.3%, 73.9% and 100% with methanol with a dosage of 30 mg/L. The kinetic analysis and calculation revealed that the greatest denitrification rate was 0.0107 mg TN/mg MLVSSṡd with sodium acetate of 60 mg/L. As to carbon consumption rate, however, the highest value occurred in the blank test with a rate of 0.1955 mg COD/mg MLVSSṡd. Also, further economic analysis proved leachate to be pragmatic external carbon source whose cost was far cheaper than methanol.

Methylobacterium extorquens AM1 produces a novel type of acyl-homoserine lactone with a double unsaturated side chain under methylotrophic growth conditions.

PubMed

Nieto Penalver, Carlos G; Morin, Danièle; Cantet, Franck; Saurel, Olivier; Milon, Alain; Vorholt, Julia A

2006-01-23

Acyl-homoserine lactones (acyl-HSLs) have emerged as important regulatory molecules for many gram-negative bacteria. We have found that Methylobacterium extorquens AM1, a member of the pink-pigmented facultative methylotrophs commonly present on plant surfaces, produces several acyl-HSLs depending upon the carbon source. A novel HSL was discovered with a double unsaturated carbon chain (N-(tetradecenoyl)) (C14:2) and characterized by MS and proton NMR. This long-chain acyl-HSL is synthesized by MlaI that also directs synthesis of C14:1-HSL. The Alphaproteobacterium also produces N-hexanoyl-HSL (C6-HSL) and N-octanoyl-HSL (C8-HSL) via MsaI.

Effect of carbon source type on intracellular stored polymers during endogenous denitritation (ED) treating landfill leachate.

PubMed

Miao, Lei; Wang, Shuying; Li, Baikun; Cao, Tianhao; Zhang, Fangzhai; Wang, Zhong; Peng, Yongzhen

2016-09-01

Glycogen accumulating organisms (GAOs) capable of storing organic compounds as polyhydroxyalkanoate (PHA) have been used for endogenous denitritation (ED), but the effect of carbon sources type on nitrogen removal performance of GAOs treating landfill leachate is unclear. In this study, a successful ED system treating landfill leachate (COD/NH4(+)-N (C/N): 4) without external carbon source addition was applied. The mature leachate with C/N of 1 was used as the feeding base solution, with acetate, propionate, and glucose examined as the carbon sources, and their effects on yields and compositions of PHA produced by GAOs were determined and associated with nitrogen removal performance. In the case of sole carbon source, acetate was much easier to be stored than propionate and glucose, which led to a higher nitrogen removal efficiency. Glucose had the lowest amount of PHA storage and led to the lowest performance. In the case of composite carbon sources (two scenarios: acetate + propionate; acetate + propionate + glucose), GAOs stored sufficient PHA and exhibited similar nitrogen removal efficiencies. Moreover, type of carbon source influenced the compositions of PHA. The polyhydroxybutyrate (PHB) fraction in PHA was far more than polyhydroxyvalerate (PHV) in all tests. PHV was synthesized only when acetate existed in carbon source. The microbial diversity analysis revealed that Proteobacteria was the most abundant phylum. Among the 108 genera detected in this ED system, the genera responsible for denitritation were Thauera, Paracoccus, Ottowia and Comamonadaceae_unclassified, accounting for 46.21% of total bacteria. Especially, Paracoccus and Comamonadaceae_unclassified transformed the carbon source into PHA for denitritation, and carried out endogenous denitritation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis of hydrogen-carbon clathrate material and hydrogen evolution therefrom at moderate temperatures and pressures

DOEpatents

Lueking, Angela [State College, PA; Narayanan, Deepa [Redmond, WA

2011-03-08

A process for making a hydrogenated carbon material is provided which includes forming a mixture of a carbon source, particularly a carbonaceous material, and a hydrogen source. The mixture is reacted under reaction conditions such that hydrogen is generated and/or released from the hydrogen source, an amorphous diamond-like carbon is formed, and at least a portion of the generated and/or released hydrogen associates with the amorphous diamond-like carbon, thereby forming a hydrogenated carbon material. A hydrogenated carbon material including a hydrogen carbon clathrate is characterized by evolution of molecular hydrogen at room temperature at atmospheric pressure in particular embodiments of methods and compositions according to the present invention.

Method for the production of dicarboxylic acids

DOEpatents

Nghiem, N.P.; Donnelly, M.; Millard, C.S.; Stols, L.

1999-02-09

The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of (a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; (b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; (c) controllably releasing oxygen to maintain the aerobic atmosphere; (d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/l up to about 1 g/l; (e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; (f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of {>=}1 g/l; and (g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism. 7 figs.

Method for the production of dicarboxylic acids

DOEpatents

Nghiem, Nhuan Phu; Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

1999-01-01

The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; c) controllably releasing oxygen to maintain the aerobic atmosphere; d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/L up to about 1 g/L; e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of .gtoreq.1 g/L; and g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism.

The role of hydrology in annual organic carbon loads and terrestrial organic matter export from a midwestern agricultural watershed

NASA Astrophysics Data System (ADS)

Dalzell, Brent J.; Filley, Timothy R.; Harbor, Jon M.

2007-03-01

Defining the control that hydrology exerts on organic carbon (OC) export at the watershed scale is important for understanding how the source and quantity of OC in streams and rivers is influenced by climate change or by landscape drainage. To this end, molecular (lignin phenol), stable carbon isotope, and dissolved organic carbon (DOC) data were collected over a range of flow conditions to examine the influence of hydrology on annual OC export from an 850 km 2 Midwestern United States agricultural watershed located in west central Indiana. In years 2002 and 2003, modeled annual DOC loads were 19.5 and 14.1 kg ha -1yr -1, while 71% and 85%, respectively, of the total annual OC was exported in flow events occurring during less than 20% of that time. These results highlight the importance of short-duration, high-discharge events (common in smaller watersheds) in controlling annual OC export. Based on reported increases in annual stream discharge coupled with current estimates of DOC export, annual DOC loads in this watershed may have increased by up to 40% over the past 50 years. Molecular (lignin phenol) characterization of quantity and relative degradation state of terrestrial OC shows as much temporal variability of lignin parameters (in high molecular weight dissolved organic carbon) in this one watershed as that demonstrated in previously published studies of dissolved organic matter in the Mississippi and Amazon Rivers. These results suggest that hydrologic variability is at least as important in determining the nature and extent of OC export as geographic variability. Moreover, molecular and bulk stable carbon isotope data from high molecular weight dissolved organic carbon and colloidal organic carbon showed that increased stream flow from the study watershed was responsible for increased export of agriculturally derived OC. When considered in the context of results from other studies that show the importance of flood events and in-stream processing of terrestrial organic carbon, our results show how hydrologic variability in smaller watersheds can reflect landscape-scale carbon dynamics in ways that cannot necessarily be measured at the outlets of large rivers due to multiple source signals and attenuated hydrology.

Morphology and topography study of graphene synthesized from plant oil

NASA Astrophysics Data System (ADS)

Robaiah, M.; Rusop, M.; Abdullah, S.; Khusaimi, Z.; Azhan, H.; Laila, M. O.; Salifairus, M. J.; Asli, N. A.

2018-05-01

The graphene is material consists of bonded atom carbon atoms in sheet form one atom thick. The different types of carbon sources which are refined corn oil, palm oil and waste cooking palm oil were used as carbon feedstock to supply carbon atom for synthesizing graphene on the nickel substrate by thermal chemical vapour deposition. The substrate and carbon sources were placed in double zone furnaces. The carbon sources and the substrate were heated at 300 °C and 900 °C respectively. The both furnaces were switched off after synthesis time for cooling process finish. The formation of the graphene on the Ni surface appears due to segregation and precipitation of a high amount of carbon from the source material during the cooling process. FESEM, AFM, UV-VIS Spectroscopy and Raman Spectroscopy were used to characterize and synthesized graphene.

New PHA products using unrelated carbon sources

PubMed Central

Matias, Fernanda; de Andrade Rodrigues, Maria Filomena

2011-01-01

Polyhydroxyalkanoates (PHA) are natural polyesters stored by a wide range of bacteria as carbon source reserve. Due to its chemical characteristics and biodegradability PHA can be used in chemical, medical and pharmaceutical industry for many human purposes. Over the past years, few Burkholderia species have become known for production of PHA. Aside from that, these bacteria seem to be interesting for discovering new PHA compositions which is important to different industrial applications. In this paper, we introduce two new strains which belong either to Burkholderia cepacia complex (Bcc) or genomovar-type, Burkholderia cepacia SA3J and Burkholderia contaminans I29B, both PHA producers from unrelated carbon sources. The classification was based on 16S rDNA and recA partial sequence genes and cell wall fatty acids composition. These two strains were capable to produce different types of PHA monomers or precursors. Unrelated carbon sources were used for growth and PHA accumulation. The amount of carbon source evaluated, or mixtures of them, was increased with every new experiment until it reaches eighteen carbon sources. As first bioprospection experiments staining methods were used with colony fluorescent dye Nile Red and the cell fluorescent dye Nile Blue A. Gas chromatography analysis coupled to mass spectrometry was used to evaluate the PHA composition on each strain cultivated on different carbon sources. The synthesized polymers were composed by short chain length-PHA (scl-PHA), especially polyhydroxybutyrate, and medium chain length-PHA (mcl-PHA) depending on the carbon source used. PMID:24031764

The Effects of Different External Carbon Sources on Nitrous Oxide Emissions during Denitrification in Biological Nutrient Removal Processes

NASA Astrophysics Data System (ADS)

Hu, Xiang; Zhang, Jing; Hou, Hongxun

2018-01-01

The aim of this study was to investigate the effects of two different external carbon sources (acetate and ethanol) on the nitrous oxide (N2O) emissions during denitrification in biological nutrient removal processes. Results showed that external carbon source significantly influenced N2O emissions during the denitrification process. When acetate served as the external carbon source, 0.49 mg N/L and 0.85 mg N/L of N2O was produced during the denitrificaiton processes in anoxic and anaerobic/anoxic experiments, giving a ratio of N2O-N production to TN removal of 2.37% and 4.96%, respectively. Compared with acetate, the amount of N2O production is negligible when ethanol used as external carbon addition. This suggested that ethanol is a potential alternative external carbon source for acetate from the point of view of N2O emissions.

Specific ultra-violet absorbance as an indicator measurement of merucry sources in an Adirondack River basin

USGS Publications Warehouse

Burns, Douglas A.; Aiken, George R.; Bradley, Paul M.; Journey, Celeste A.; Schelker, Jakob

2013-01-01

The Adirondack region of New York has been identified as a hot spot where high methylmercury concentrations are found in surface waters and biota, yet mercury (Hg) concentrations vary widely in this region. We collected stream and groundwater samples for Hg and organic carbon analyses across the upper Hudson River, a 493 km2 basin in the central Adirondacks to evaluate and model the sources of variation in filtered total Hg (FTHg) concentrations. Variability in FTHg concentrations during the growing seasons (May-Oct) of 2007-2009 in Fishing Brook, a 66-km2 sub-basin, was better explained by specific ultra-violet absorbance at 254 nm (SUVA254), a measure of organic carbon aromaticity, than by dissolved organic carbon (DOC) concentrations, a commonly used Hg indicator. SUVA254 was a stronger predictor of FTHg concentrations during the growing season than during the dormant season. Multiple linear regression models that included SUVA254 values and DOC concentrations could explain 75 % of the variation in FTHg concentrations on an annual basis and 84 % during the growing season. A multiple linear regression landscape modeling approach applied to 27 synoptic sites across the upper Hudson basin found that higher SUVA254 values are associated with gentler slopes, and greater riparian area, and lower SUVA254 values are associated with an increasing influence of open water. We hypothesize that the strong Hg?SUVA254 relation in this basin reflects distinct patterns of FTHg and SUVA254 that are characteristic of source areas that control the mobilization of Hg to surface waters, and that the seasonal influence of these source areas varies in this heterogeneous basin landscape.

Radiocarbon chronology of the last deglaciation in the Baffin Bay reveals asynchronous melting of Arctic and Laurentide ice sheets

NASA Astrophysics Data System (ADS)

Jackson, Rebecca; Kucera, Michal; Vogt, Christoph; Wacker, Lukas

2016-04-01

The transition from the last ice age into the Holocene interglacial was characterised by rapid retreat of North American ice sheets, discharging large quantities of meltwater into the Labrador Sea. Whereas the meltwater chronology of the Laurentide Ice Sheet is well documented, the deglacial history of the American Arctic ice sheets (Inuit Ice sheet and northern Greenland Ice Sheet) draining into the Labrador Sea via the Baffin Bay is less well constrained. Here we present the first high-resolution radiocarbon-dated deglacial records from the Canadian and Greenland margins of the central Baffin Bay. Sedimentological and geochemical data confirm the presence during Termination I of two events of enhanced delivery of detrital carbonate (Baffin Bay Detrital Carbonate Events) dated to 14.2-13.7 ka BP and 12.7-11 ka BP. The events are synchronous across the Baffin Bay and their mineralogical signature indicates a common source of detrital carbonate from the Canadian Arctic, with a synchronous clastic source proximal to Greenland. The events postdate Heinrich layers and their onset is not linked to Greenland temperature change. This indicates that the deglaciation of American Arctic ice sheets and associated meltwater discharge were decoupled from the dominant North Atlantic climate mode.

Anaerobic carboxydotrophic bacteria in geothermal springs identified using stable isotope probing

PubMed Central

Brady, Allyson L.; Sharp, Christine E.; Grasby, Stephen E.; Dunfield, Peter F.

2015-01-01

Carbon monoxide (CO) is a potential energy and carbon source for thermophilic bacteria in geothermal environments. Geothermal sites ranging in temperature from 45 to 65°C were investigated for the presence and activity of anaerobic CO-oxidizing bacteria. Anaerobic CO oxidation potentials were measured at up to 48.9 μmoles CO g−1 (wet weight) day−1 within five selected sites. Active anaerobic carboxydotrophic bacteria were identified using 13CO DNA stable isotope probing (SIP) combined with pyrosequencing of 16S rRNA genes amplified from labeled DNA. Bacterial communities identified in heavy DNA fractions were predominated by Firmicutes, which comprised up to 95% of all sequences in 13CO incubations. The predominant bacteria that assimilated 13C derived from CO were closely related (>98% 16S rRNA gene sequence identity) to genera of known carboxydotrophs including Thermincola, Desulfotomaculum, Thermolithobacter, and Carboxydocella, although a few species with lower similarity to known bacteria were also found that may represent previously unconfirmed CO-oxidizers. While the distribution was variable, many of the same OTUs were identified across sample sites from different temperature regimes. These results show that bacteria capable of using CO as a carbon source are common in geothermal springs, and that thermophilic carboxydotrophs are probably already quite well known from cultivation studies. PMID:26388850

Anaerobic carboxydotrophic bacteria in geothermal springs identified using stable isotope probing.

PubMed

Brady, Allyson L; Sharp, Christine E; Grasby, Stephen E; Dunfield, Peter F

2015-01-01

Carbon monoxide (CO) is a potential energy and carbon source for thermophilic bacteria in geothermal environments. Geothermal sites ranging in temperature from 45 to 65°C were investigated for the presence and activity of anaerobic CO-oxidizing bacteria. Anaerobic CO oxidation potentials were measured at up to 48.9 μmoles CO g(-1) (wet weight) day(-1) within five selected sites. Active anaerobic carboxydotrophic bacteria were identified using (13)CO DNA stable isotope probing (SIP) combined with pyrosequencing of 16S rRNA genes amplified from labeled DNA. Bacterial communities identified in heavy DNA fractions were predominated by Firmicutes, which comprised up to 95% of all sequences in (13)CO incubations. The predominant bacteria that assimilated (13)C derived from CO were closely related (>98% 16S rRNA gene sequence identity) to genera of known carboxydotrophs including Thermincola, Desulfotomaculum, Thermolithobacter, and Carboxydocella, although a few species with lower similarity to known bacteria were also found that may represent previously unconfirmed CO-oxidizers. While the distribution was variable, many of the same OTUs were identified across sample sites from different temperature regimes. These results show that bacteria capable of using CO as a carbon source are common in geothermal springs, and that thermophilic carboxydotrophs are probably already quite well known from cultivation studies.

Deep mantle: Enriched carbon source detected

NASA Astrophysics Data System (ADS)

Barry, Peter H.

2017-09-01

Estimates of carbon in the deep mantle vary by more than an order of magnitude. Coupled volcanic CO2 emission data and magma supply rates reveal a carbon-rich mantle plume source region beneath Hawai'i with 40% more carbon than previous estimates.

The nature of matrix in mixed siliciclastic-carbonate turbidites: An example from the Oquirrh-Wood River basin

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

Geslin, J.K.

1992-01-01

Upper Pennsylvanian to Lower Permian strata of the Oquirrh-Wood River basin (OWRB) in southern Idaho are dominated by mixed siliciclastic-carbonate sediment gravity flows, including amalgamated sandy turbidites or grain flows, and silty turbidites. Previously, the petrology of the carbonate fraction of mixed siliciclastic-carbonate turbidites from the OWRB has been described as predominantly micrite. A source of micrite is present in phylloid algal mounds, which comprise a carbonate platform on the eastern basin margin. Visible micritized skeletal grains and fusulinids are uncommon in these sediments. It has been proposed that the micrite was subsequently neomorphosed to microspar or large, blocky spar.more » The actual volume of micrite in these deposits is enigmatic. Classic studies of turbidite hydrodynamics indicate that matrix accounts for no more than 20 percent, and commonly less, of the experimental turbidite deposits. Therefore, it is unlikely, based on hydrodynamics, that mixed siliciclastic-carbonate turbidites contain more than 20 percent micritic matrix. To resolve this enigma, multiple samples of the siliciclastic-carbonate turbidites from the OWRB were examined using a fluorescence (blue-light) microscope and the white-card technique. Under fluorescence the carbonate fraction of these samples was determined to contain micritized skeletal fragments; peloids, and micritized fusulinids. During diagenesis many of the carbonate grains were deformed and crushed to form carbonate pseudomatrix. Abundant carbonate grains indicate that mixed siliciclastic-carbonate turbidites from the OWRB adhere to established hydrodynamic principles, and contain less than 20 percent detrital matrix.« less

Differences in the OC/EC Ratios that Characterize Ambient and Source Aerosols due to Thermal-Optical Analysis

EPA Science Inventory

Thermal-optical analysis (TOA) is typically used to measure the OC/EC (organic carbon/elemental carbon) and EC/TC (elemental carbon/total carbon) ratios in source and atmospheric aerosols. The present study utilizes a dual-optical carbon aerosol analyzer to examine the effects of...

Constraining the subsoil carbon source to cave-air CO2 and speleothem calcite in central Texas

NASA Astrophysics Data System (ADS)

Bergel, Shelly J.; Carlson, Peter E.; Larson, Toti E.; Wood, Chris T.; Johnson, Kathleen R.; Banner, Jay L.; Breecker, Daniel O.

2017-11-01

Canonical models for speleothem formation and the subsurface carbon cycle invoke soil respiration as the dominant carbon source. However, evidence from some karst regions suggests that belowground CO2 originates from a deeper, older source. We therefore investigated the carbon sources to central Texas caves. Drip-water chemistry of two caves in central Texas implies equilibration with calcite at CO2 concentrations (PCO2_sat) higher than the maximum CO2 concentrations observed in overlying soils. This observation suggests that CO2 is added to waters after they percolate through the soils, which requires a subsoil carbon source. We directly evaluate the carbon isotope composition of the subsoil carbon source using δ13C measurements on cave-air CO2, which we independently demonstrate has little to no contribution from host rock carbon. We do so using the oxidative ratio, OR, defined as the number of moles of O2 consumed per mole of CO2 produced during respiration. However, additional belowground processes that affect O2 and CO2 concentrations, such as gas-water exchange and/or diffusion, may also influence the measured oxidative ratio, yielding an apparent OR (ORapparent). Cave air in Natural Bridge South Cavern has ORapparent values (1.09 ± 0.06) indistinguishable from those expected for respiration alone (1.08 ± 0.06). Pore space gases from soils above the cave have lower values (ORapparent = 0.67 ± 0.05) consistent with respiration and gas transport by diffusion. The simplest explanation for these observations is that cave air in NB South is influenced by respiration in open-system bedrock fractures such that neither diffusion nor exchange with water influence the composition of the cave air. The radiocarbon activities of NB South cave-air CO2 suggest the subsoil carbon source is hundreds of years old. The calculated δ13C values of the subsoil carbon source are consistent with tree-sourced carbon (perhaps decomposing root matter), the δ13C values of which have shifted during industrialization due to changes in the δ13C values and concentrations of atmospheric CO2. Seasonal variations in PCO2_sat in most of the drip waters suggest that these waters exchange with ventilated bedrock fractures in the epikarst, implying that the subsoil CO2 source contributes carbon to speleothems.

40 CFR 458.45 - Standards of performance for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... paragraph, which may be discharged from the carbon black lamp process by a new source subject to the provisions of this subpart: There shall be no discharge of process waste water pollutants to navigable waters. ...) EFFLUENT GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp...

Growth of graphene films from non-gaseous carbon sources

DOEpatents

Tour, James; Sun, Zhengzong; Yan, Zheng; Ruan, Gedeng; Peng, Zhiwei

2015-08-04

In various embodiments, the present disclosure provides methods of forming graphene films by: (1) depositing a non-gaseous carbon source onto a catalyst surface; (2) exposing the non-gaseous carbon source to at least one gas with a flow rate; and (3) initiating the conversion of the non-gaseous carbon source to the graphene film, where the thickness of the graphene film is controllable by the gas flow rate. Additional embodiments of the present disclosure pertain to graphene films made in accordance with the methods of the present disclosure.

The influence of various carbon and nitrogen sources on oil production by Fusarium oxysporum.

PubMed

Joshi, S; Mathur, J M

1987-01-01

The oil-synthesizing capacity of Fusarium oxysporum, cultivated on basal nutrient medium, was evaluated using different carbon and nitrogen sources. In one of the media, molasses was also used as a principal carbon source. Media containing glucose and ammonium nitrate were found to be most efficient for oil production. Fatty acid profile of the fungal oil indicated the presence of a wide range of fatty acids ranging from C8 to C24. Fatty acid composition largely depends on the type of carbon and nitrogen sources.

Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

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

Koven, C. D.; Chambers, J. Q.; Georgiou, K.

To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore » situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr −1 increasing CO 2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO 2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

Controls on terrestrial carbon feedbacks by productivity versus turnover in the CMIP5 Earth System Models

DOE PAGES

Koven, C. D.; Chambers, J. Q.; Georgiou, K.; ...

2015-09-07

To better understand sources of uncertainty in projections of terrestrial carbon cycle feedbacks, we present an approach to separate the controls on modeled carbon changes. We separate carbon changes into four categories using a linearized, equilibrium approach: those arising from changed inputs (productivity-driven changes), and outputs (turnover-driven changes), of both the live and dead carbon pools. Using Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations for five models, we find that changes to the live pools are primarily explained by productivity-driven changes, with only one model showing large compensating changes to live carbon turnover times. For dead carbon pools, themore » situation is more complex as all models predict a large reduction in turnover times in response to increases in productivity. This response arises from the common representation of a broad spectrum of decomposition turnover times via a multi-pool approach, in which flux-weighted turnover times are faster than mass-weighted turnover times. This leads to a shift in the distribution of carbon among dead pools in response to changes in inputs, and therefore a transient but long-lived reduction in turnover times. Since this behavior, a reduction in inferred turnover times resulting from an increase in inputs, is superficially similar to priming processes, but occurring without the mechanisms responsible for priming, we call the phenomenon "false priming", and show that it masks much of the intrinsic changes to dead carbon turnover times as a result of changing climate. These patterns hold across the fully coupled, biogeochemically coupled, and radiatively coupled 1 % yr −1 increasing CO 2 experiments. We disaggregate inter-model uncertainty in the globally integrated equilibrium carbon responses to initial turnover times, initial productivity, fractional changes in turnover, and fractional changes in productivity. For both the live and dead carbon pools, inter-model spread in carbon changes arising from initial conditions is dominated by model disagreement on turnover times, whereas inter-model spread in carbon changes from fractional changes to these terms is dominated by model disagreement on changes to productivity in response to both warming and CO 2 fertilization. However, the lack of changing turnover time control on carbon responses, for both live and dead carbon pools, in response to the imposed forcings may arise from a common lack of process representation behind changing turnover times (e.g., allocation and mortality for live carbon; permafrost, microbial dynamics, and mineral stabilization for dead carbon), rather than a true estimate of the importance of these processes.« less

Stimulation of Microbially Mediated Arsenic Release in Bangladesh Aquifers by Young Carbon Indicated by Radiocarbon Analysis of Sedimentary Bacterial Lipids.

PubMed

Whaley-Martin, K J; Mailloux, B J; van Geen, A; Bostick, B C; Silvern, R F; Kim, C; Ahmed, K M; Choudhury, I; Slater, G F

2016-07-19

The sources of reduced carbon driving the microbially mediated release of arsenic to shallow groundwater in Bangladesh remain poorly understood. Using radiocarbon analysis of phospholipid fatty acids (PLFAs) and potential carbon pools, the abundance and carbon sources of the active, sediment-associated, in situ bacterial communities inhabiting shallow aquifers (<30 m) at two sites in Araihazar, Bangladesh, were investigated. At both sites, sedimentary organic carbon (SOC) Δ(14)C signatures of -631 ± 54‰ (n = 12) were significantly depleted relative to dissolved inorganic carbon (DIC) of +24 ± 30‰ and dissolved organic carbon (DOC) of -230 ± 100‰. Sediment-associated PLFA Δ(14)C signatures (n = 10) at Site F (-167‰ to +20‰) and Site B (-163‰ to +21‰) were highly consistent and indicated utilization of carbon sources younger than the SOC, likely from the DOC pool. Sediment-associated PLFA Δ(14)C signatures were consistent with previously determined Δ(14)C signatures of microbial DNA sampled from groundwater at Site F indicating that the carbon source for these two components of the subsurface microbial community is consistent and is temporally stable over the two years between studies. These results demonstrate that the utilization of relatively young carbon sources by the subsurface microbial community occurs at sites with varying hydrology. Further they indicate that these young carbon sources drive the metabolism of the more abundant sediment-associated microbial communities that are presumably more capable of Fe reduction and associated release of As. This implies that an introduction of younger carbon to as of yet unaffected sediments (such as those comprising the deeper Pleistocene aquifer) could stimulate microbial communities and result in arsenic release.

Determination of the carbonate dissolution mechanism of Lactococcus sp.

NASA Astrophysics Data System (ADS)

Yanmiş, Derya; Orhan, Furkan; Güllüce, Medine; Şahin, Fikrettin

2017-04-01

Magnesite, the main source for magnesium and magnesium derivatives, are also commonly used in the production of caustic, dead-burned and fused magnesia. World magnesite resources are estimated to be at 12 billion tonnes mostly located in China, Russia, North Korea, Australia and Turkey. Turkey is the second producer of the magnesite. Magnesite deposits in Turkey are sedimentary magnesite which have been formed in specific conditions as high concentrations of MgSO4 and CO2 and presence of certain organic salts or created by hot or cold dissolution connected with carbonate rocks mainly with dolomites. According to the genesis of magnesite deposits, they have some impurities as calcium, quartz, iron, etc. Impurities of magnesite, especially CaCO3, reduce its economic value and industrial usability. In our previous study, we have performed biotechnologically enrichment of magnesite by Lactococcus sp., which gave significantly important results. However, we had no information about carbonate dissolution mechanism of bacteria. Therefore, it is aimed to reveal the metabolites of Lactococcus sp. and mechanism leading to the carbonate dissolution (MgCO3 and CaCO3).

Denitrification-Efficiencies of Alternate Carbon Sources

DTIC Science & Technology

1984-07-01

carbon source evaluated, while sweet whey, corn steep liquor , acid whey and soluble potato solids followed in order of decreasing efficiency. Three of...denitrification and total organic carbon removal with ’I. sweet whey 11 3. Percent denitrification and total organic carbon removal with corn steep liquor ...and total organic carbon removal with hydrolyzed sludge 18 10. Percent denitrification and total organic carbon removal with fish stick 19 11

Isolation and Characterization of Anaerobic Bacteria for Symbiotic Recycling of Uric Acid Nitrogen in the Gut of Various Termites

PubMed Central

Thong-On, Arunee; Suzuki, Katsuyuki; Noda, Satoko; Inoue, Jun-ichi; Kajiwara, Susumu; Ohkuma, Moriya

2012-01-01

Recycling of the nitrogenous waste uric acid (UA) of wood-feeding termites by their gut bacteria is one of the significant aspects of symbiosis for the conservation of nitrogen sources. Diverse anaerobic UA-degrading bacteria comprising 16 species were isolated from the gut of eight termite species, and were assigned to Clostridia, Enterobacteriaceae, and low G+C Gram-positive cocci. UA-degrading Clostridia had never been isolated from termite guts. UA-degrading ability was sporadically distributed among phylogenetically various culturable anaerobic bacteria from termite guts. A strain of Clostridium sp., which was commonly isolated from three termite species and represented a probable new species in cluster XIVa of clostridia, utilized UA as a nitrogen source but not as a sole carbon and energy source. This feature is in clear contrast to that of well-studied purinolytic clostridia or previously isolated UA degraders from termite guts, which also utilize UA as a sole carbon and energy source. Ammonia is the major nitrogenous product of UA degradation. Various purines stimulated the growth of this strain when added to an otherwise growth-limiting, nitrogen poor medium. The bacterial species involved the recycling of UA nitrogen in the gut microbial community of termites are more diverse in terms of both taxonomy and nutritional physiology than previously recognized. PMID:22791052

Nutrient transitions are a source of persisters in Escherichia coli biofilms.

PubMed

Amato, Stephanie M; Brynildsen, Mark P

2014-01-01

Chronic and recurrent infections have been attributed to persisters in biofilms, and despite this importance, the mechanisms of persister formation in biofilms remain unclear. The plethora of biofilm characteristics that could give rise to persisters, including slower growth, quorum signaling, oxidative stress, and nutrient heterogeneity, have complicated efforts to delineate formation pathways that generate persisters during biofilm development. Here we sought to specifically determine whether nutrient transitions, which are a common metabolic stress encountered within surface-attached communities, stimulate persister formation in biofilms and if so, to then identify the pathway. To accomplish this, we established an experimental methodology where nutrient availability to biofilm cells could be controlled exogenously, and then used that method to discover that diauxic carbon source transitions stimulated persister formation in Escherichia coli biofilms. Previously, we found that carbon source transitions stimulate persister formation in planktonic E. coli cultures, through a pathway that involved ppGpp and nucleoid-associated proteins, and therefore, tested the functionality of that pathway in biofilms. Biofilm persister formation was also found to be dependent on ppGpp and nucleoid-associated proteins, but the importance of specific proteins and enzymes between biofilm and planktonic lifestyles was significantly different. Data presented here support the increasingly appreciated role of ppGpp as a central mediator of bacterial persistence and demonstrate that nutrient transitions can be a source of persisters in biofilms.

Dynamic Balancing of Isoprene Carbon Sources Reflects Photosynthetic and Photorespiratory Responses to Temperature Stress1[W][OPEN

PubMed Central

Chambers, Jeffrey; Alves, Eliane G.; Teixeira, Andrea; Garcia, Sabrina; Holm, Jennifer; Higuchi, Niro; Manzi, Antonio; Abrell, Leif; Fuentes, Jose D.; Nielsen, Lars K.; Torn, Margaret S.; Vickers, Claudia E.

2014-01-01

The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-13C]glycine (a photorespiratory intermediate) stimulated emissions of [13C1–5]isoprene and 13CO2, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures. PMID:25318937

Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress.

PubMed

Jardine, Kolby; Chambers, Jeffrey; Alves, Eliane G; Teixeira, Andrea; Garcia, Sabrina; Holm, Jennifer; Higuchi, Niro; Manzi, Antonio; Abrell, Leif; Fuentes, Jose D; Nielsen, Lars K; Torn, Margaret S; Vickers, Claudia E

2014-12-01

The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-(13)C]glycine (a photorespiratory intermediate) stimulated emissions of [(13)C1-5]isoprene and (13)CO2, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures. © 2014 American Society of Plant Biologists. All Rights Reserved.

Abiotic synthesis of organic compounds from carbon disulfide under hydrothermal conditions.

PubMed

Rushdi, Ahmed I; Simoneit, Bernd R T

2005-12-01

Abiotic formation of organic compounds under hydrothermal conditions is of interest to bio, geo-, and cosmochemists. Oceanic sulfur-rich hydrothermal systems have been proposed as settings for the abiotic synthesis of organic compounds. Carbon disulfide is a common component of magmatic and hot spring gases, and is present in marine and terrestrial hydrothermal systems. Thus, its reactivity should be considered as another carbon source in addition to carbon dioxide in reductive aqueous thermosynthesis. We have examined the formation of organic compounds in aqueous solutions of carbon disulfide and oxalic acid at 175 degrees C for 5 and 72 h. The synthesis products from carbon disulfide in acidic aqueous solutions yielded a series of organic sulfur compounds. The major compounds after 5 h of reaction included dimethyl polysulfides (54.5%), methyl perthioacetate (27.6%), dimethyl trithiocarbonate (6.8%), trithianes (2.7%), hexathiepane (1.4%), trithiolanes (0.8%), and trithiacycloheptanes (0.3%). The main compounds after 72 h of reaction consisted of trithiacycloheptanes (39.4%), pentathiepane (11.6%), tetrathiocyclooctanes (11.5%), trithiolanes (10.6%), tetrathianes (4.4%), trithianes (1.2%), dimethyl trisulfide (1.1%), and numerous minor compounds. It is concluded that the abiotic formation of aliphatic straight-chain and cyclic polysulfides is possible under hydrothermal conditions and warrants further studies.

Effects of acidification on the isotopic ratios of Neotropical otter tooth dentin.

PubMed

Carrasco, Thayara S; Botta, Silvina; Machado, Rodrigo; Colares, Elton P; Secchi, Eduardo R

2018-05-30

Stable carbon and nitrogen isotope ratios are widely used in ecological studies providing important information on the trophic ecology and habitat use of consumers. However, some factors may lead to isotopic variability, which makes difficult the interpretation of data, such as the presence of inorganic carbon in mineralized tissues. In order to remove the inorganic carbon, acidification is a commonly used treatment. The effects of two methods of acidification were tested: (i) dentin acidification with 10% HCl using the 'drop-by-drop' technique, and (ii) dentin acidification in an 'HCl atmosphere', by exposing the dentin to vaporous 30% hydrochloric acid. Results were compared with untreated subsamples. The stable carbon and nitrogen ratios of untreated and acidified subsamples were measured using an elemental analyzer coupled to an isotope ratio mass spectrometer. The nitrogen isotopic ratios were statistically different between the two acidification treatments, but no significant changes in carbon isotopic ratios were found in acidified and untreated samples. The results indicated that acidification had no effect on carbon isotopic ratios of Neotropical otter tooth dentin, while introducing a source of error in nitrogen isotopic ratios. Therefore, we conclude that acidification is an unnecessary step for C and N stable isotope analysis. Copyright © 2018 John Wiley & Sons, Ltd.

Refining soil organic carbon stock estimates for China’s palustrine wetlands

NASA Astrophysics Data System (ADS)

Ma, Kun; Liu, Junguo; Zhang, Ying; Parry, Lauren E.; Holden, Joseph; Ciais, Philippe

2015-12-01

Palustrine wetlands (PWs) include all bogs, fens, swamps and marshes that are non-saline and which are not lakes or rivers. They therefore form a highly important group of wetlands which hold large carbon stocks. If these wetlands are not protected properly they could become a net carbon source in the future. Compilation of spatially explicit wetland databases, national inventory data and in situ measurement of soil organic carbon (SOC) could be useful to better quantify SOC and formulate long-term strategies for mitigating global climate change. In this study, a synergistic mapping approach was used to create a hybrid map for PWs for China and to estimate their SOC content. Total SOC storage in PWs was estimated to be 4.3 ± 1.4 Pg C, with a SOC density of 31.17 (±10.55) kg C m-2 in the upper 1 m of the soil layer. This carbon stock is concentrated in Northeast China (49%) and the Qinghai-Tibet Plateau (41%). Given the large pool of carbon stored in PWs compared to other soil types, we suggest that urgent monitoring programmes on SOC should be established in regions with very few datasets, but where PWs appear to be common such as the Tibet region and Northwest China.

Hydrologic control of carbon cycling and aged carbon discharge in the Congo River basin

NASA Astrophysics Data System (ADS)

Schefuß, Enno; Eglinton, Timothy I.; Spencer-Jones, Charlotte L.; Rullkötter, Jürgen; de Pol-Holz, Ricardo; Talbot, Helen M.; Grootes, Pieter M.; Schneider, Ralph R.

2016-09-01

The age of organic material discharged by rivers provides information about its sources and carbon cycling processes within watersheds. Although elevated ages in fluvially transported organic matter are usually explained by erosion of soils and sedimentary deposits, it is commonly assumed that mainly young organic material is discharged from flat tropical watersheds due to their extensive plant cover and rapid carbon turnover. Here we present compound-specific radiocarbon data of terrigenous organic fractions from a sedimentary archive offshore the Congo River, in conjunction with molecular markers for methane-producing land cover reflecting wetland extent. We find that the Congo River has been discharging aged organic matter for several thousand years, with apparently increasing ages from the mid- to the Late Holocene. This suggests that aged organic matter in modern samples is concealed by radiocarbon from atmospheric nuclear weapons testing. By comparison to indicators for past rainfall changes we detect a systematic control of organic matter sequestration and release by continental hydrology, mediating temporary carbon storage in wetlands. As aridification also leads to exposure and rapid remineralization of large amounts of previously stored labile organic matter, we infer that this process may cause a profound direct climate feedback that is at present underestimated in carbon cycle assessments.

Resolution of the carbon contamination problem in ion irradiation experiments

NASA Astrophysics Data System (ADS)

Was, G. S.; Taller, S.; Jiao, Z.; Monterrosa, A. M.; Woodley, D.; Jennings, D.; Kubley, T.; Naab, F.; Toader, O.; Uberseder, E.

2017-12-01

The widely experienced problem of carbon uptake in samples during ion irradiation was systematically investigated to identify the source of carbon and to develop mitigation techniques. Possible sources of carbon included carbon ions or neutrals incorporated into the ion beam, hydrocarbons in the vacuum system, and carbon species on the sample and fixture surfaces. Secondary ion mass spectrometry, atom probe tomography, elastic backscattering spectrometry, and principally, nuclear reaction analysis, were used to profile carbon in a variety of substrates prior to and following irradiation with Fe2+ ions at high temperature. Ion irradiation of high purity Si and Ni, and also of alloy 800H coated with a thin film of alumina eliminated the ion beam as the source of carbon. Hydrocarbons in the vacuum and/or on the sample and fixtures was the source of the carbon that became incorporated into the samples during irradiation. Plasma cleaning of the sample and sample stage, and incorporation of a liquid nitrogen cold trap both individually and especially in combination, completely eliminated the uptake of carbon during heavy ion irradiation. While less convenient, coating the sample with a thin film of alumina was also effective in eliminating carbon incorporation.

Measurement of Urban fluxes of CO2 and water

NASA Astrophysics Data System (ADS)

Grimmond, S.; Crawford, B.; Offerle, B.; Hom, J.

2006-05-01

Measurements of surface-atmosphere fluxes of carbon dioxide (FCO2) and latent heat in urban environments are rare even though cities are a major source of atmospheric CO2 and users of water. In this paper, an overview of urban FCO2 measurements will be presented to illustrate how and where such measurements are being conducted and emerging results to date. Most of these studies have been conducted over short periods of time; few studies have considered annual sources/sinks. More investigations have been conducted, and are planned, in European cities than elsewhere, most commonly in areas of medium density urban development. The most dense urban sites are significant net sources of carbon. However, in areas where there is large amounts of vegetation present, there is a net sink of carbon during the summertime. In the second part of the presentation, more detailed attention will be directed to an ongoing measurement program in Baltimore, MD (part of the Baltimore Ecosystem Study). Eddy covariance instrumentation mounted on a tall-tower at 41.2 m has continuously measured local-scale fluxes of carbon dioxide from a suburban environment since 2001. Several features make this particular study unique: 1) for an urban area, the study site is extensively vegetated, 2) the period of record (2001-2005) is among the longest available for urban FCO2 measurements, 3) both closed-path and open-path infrared gas analyzers are used for observations, and 4) several unique data quality control and gap-filling methods have been developed for use in an urban environment. Additionally, detailed surface datasets and GIS software are used to perform flux source area analysis. Results from Baltimore indicate that FCO2 is very dependent on source area land-cover characteristics, particularly the proportion of vegetated and built surfaces. Over the course of a year, the urban surface is a strong net source of CO2, though there is considerable inter-annual variability depending on environmental conditions (e.g. average temperature, total precipitation, cicada infestation). During the growing season, there is net uptake of CO2 by the surface, but this uptake is less than in forested areas and is not enough to offset CO2 emissions for the entire year

Agenda and Meeting Summary from Final Workshop on Arctic Black Carbon: Reduction of Black Carbon from Diesel Sources

EPA Pesticide Factsheets

The U.S. Environmental Protection Agency, Battelle Memorial Institute and WWF-Russia organized the final workshop on Arctic Black Carbon: Reduction of Black Carbon from Diesel Sources on November 5, 2014 in Murmansk, Russia.

Agenda and Meeting Summary from Best Practices Training on Arctic Black Carbon: Reduction of Black Carbon from Diesel Sources

EPA Pesticide Factsheets

From April 15-19, 2013, EPA's partners hosted the Best Practices Training on Arctic Black Carbon: Reduction of Black Carbon from Diesel Sources in Murmansk, Russia. Over the course of this event, participants:

Will the use of a carbon tax for revenue generation produce an incentive to continue carbon emissions?

NASA Astrophysics Data System (ADS)

Wang, Rong; Moreno-Cruz, Juan; Caldeira, Ken

2017-05-01

Integrated assessment models are commonly used to generate optimal carbon prices based on an objective function that maximizes social welfare. Such models typically project an initially low carbon price that increases with time. This framework does not reflect the incentives of decision makers who are responsible for generating tax revenue. If a rising carbon price is to result in near-zero emissions, it must ultimately result in near-zero carbon tax revenue. That means that at some point, policy makers will be asked to increase the tax rate on carbon emissions to such an extent that carbon tax revenue will fall. Therefore, there is a risk that the use of a carbon tax to generate revenue could eventually create a perverse incentive to continue carbon emissions in order to provide a continued stream of carbon tax revenue. Using the Dynamic Integrated Climate Economy (DICE) model, we provide evidence that this risk is not a concern for the immediate future but that a revenue-generating carbon tax could create this perverse incentive as time goes on. This incentive becomes perverse at about year 2085 under the default configuration of DICE, but the timing depends on a range of factors including the cost of climate damages and the cost of decarbonizing the global energy system. While our study is based on a schematic model, it highlights the importance of considering a broader spectrum of incentives in studies using more comprehensive integrated assessment models. Our study demonstrates that the use of a carbon tax for revenue generation could potentially motivate implementation of such a tax today, but this source of revenue generation risks motivating continued carbon emissions far into the future.

Sources of dissolved and particulate organic material in Loch Vale Watershed, Rocky Mountain National Park, Colorado, USA

USGS Publications Warehouse

Baron, Jill S.; McKnight, Diane M.; Denning, A. Scott

1991-01-01

The sources of both dissolved organic carbon (DOC) and particulate organic carbon (POC) to an alpine (Sky Pond) and a subalpine lake (The Loch) in Rocky Mountain National Park were explored for four years. The importance of both autochthonous and allochthonous sources of organic matter differ, not only between alpine and subalpine locations, but also seasonally. Overall, autochthonous sources dominate the organic carbon of the alpine lake, while allochthonous sources are a more significant source of organic carbon to the subalpine lake. In the alpine lake, Sky Pond, POC makes up greater than one third of the total organic matter content of the water column, and is related to phytoplankton abundance. Dissolved organic carbon is a product of within-lake activity in Sky Pond except during spring snowmelt and early summer (May–July), when stable carbon isotope ratios suggest a terrestrial source. In the subalpine lake, The Loch, DOC is a much more important constituent of water column organic material than POC, comprising greater than 90% of the spring snowmelt organic matter, and greater than 75% of the organic matter over the rest of the year. Stable carbon isotope ratios and a very strong relation of DOC with soluble Al(tot) indicate DOC concentrations are almost entirely related to flushing of soil water from the surrounding watershed during spring snowmelt. Stable carbon isotope ratios indicate that, for both lakes, phytoplankton is an important source of DOC in the winter, while terrestrial material of plant or microbial origin contributes DOC during snowmelt and summer.

Characterization of rhizobia isolates obtained from nodules of wild genotypes of common bean.

PubMed

Cardoso, Aline Assis; Andraus, Michel de Paula; Borba, Tereza Cristina de Oliveira; Martin-Didonet, Claudia Cristina Garcia; Ferreira, Enderson Petrônio de Brito

This study aimed to evaluate the tolerance to salinity and temperature, the genetic diversity and the symbiotic efficiency of rhizobia isolates obtained from wild genotypes of common bean cultivated in soil samples from the States of Goiás, Minas Gerais and Paraná. The isolates were subjected to different NaCl concentrations (0%, 1%, 2%, 4% and 6%) at different temperatures (28°C, 33°C, 38°C, 43°C and 48°C). Genotypic characterization was performed based on BOX-PCR, REP-PCR markers and 16S rRNA sequencing. An evaluation of symbiotic efficiency was carried out under greenhouse conditions in autoclaved Leonard jars. Among 98 isolates about 45% of them and Rhizobium freirei PRF81 showed a high tolerance to temperature, while 24 isolates and Rhizobium tropici CIAT899 were able to use all of the carbon sources studied. Clustering analysis based on the ability to use carbon sources and on the tolerance to salinity and temperature grouped 49 isolates, R. tropici CIAT899 and R. tropici H12 with a similarity level of 76%. Based on genotypic characterization, 65% of the isolates showed an approximately 66% similarity with R. tropici CIAT899 and R. tropici H12. About 20% of the isolates showed symbiotic efficiency similar to or better than the best Rhizobium reference strain (R. tropici CIAT899). Phylogenetic analysis of the 16S rRNA revealed that two efficient isolates (ALSG5A1 and JPrG6A8) belong to the group of strains used as commercial inoculant for common bean in Brazil and must be assayed in field experiments. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Chemical compositions and source identification of PM₂.₅ aerosols for estimation of a diesel source surrogate.

PubMed

Sahu, Manoranjan; Hu, Shaohua; Ryan, Patrick H; Le Masters, Grace; Grinshpun, Sergey A; Chow, Judith C; Biswas, Pratim

2011-06-01

Exposure to traffic-related pollution during childhood has been associated with asthma exacerbation, and asthma incidence. The objective of the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) is to determine if the development of allergic and respiratory disease is associated with exposure to diesel engine exhaust particles. A detailed receptor model analyses was undertaken by applying positive matrix factorization (PMF) and UNMIX receptor models to two PM₂.₅ data sets: one consisting of two carbon fractions and the other of eight temperature-resolved carbon fractions. Based on the source profiles resolved from the analyses, markers of traffic-related air pollution were estimated: the elemental carbon attributed to traffic (ECAT) and elemental carbon attributed to diesel vehicle emission (ECAD). Application of UNMIX to the two data sets generated four source factors: combustion related sulfate, traffic, metal processing and soil/crustal. The PMF application generated six source factors derived from analyzing two carbon fractions and seven factors from temperature-resolved eight carbon fractions. The source factors (with source contribution estimates by mass concentrations in parentheses) are: combustion sulfate (46.8%), vegetative burning (15.8%), secondary sulfate (12.9%), diesel vehicle emission (10.9%), metal processing (7.5%), gasoline vehicle emission (5.6%) and soil/crustal (0.7%). Diesel and gasoline vehicle emission sources were separated using eight temperature-resolved organic and elemental carbon fractions. Application of PMF to both datasets also differentiated the sulfate rich source from the vegetative burning source, which are combined in a single factor by UNMIX modeling. Calculated ECAT and ECAD values at different locations indicated that traffic source impacts depend on factors such as traffic volumes, meteorological parameters, and the mode of vehicle operation apart from the proximity of the sites to highways. The difference in ECAT and ECAD, however, was less than one standard deviation. Thus, a cost benefit consideration should be used when deciding on the benefits of an eight or two carbon approach. Published by Elsevier B.V.

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 of the GOM do not appear to be substantially different from those found on the upper slope (<1000-m water depth). The highly variable fluids and gases that leave their geochemical imprints on seep carbonate of the middle and lower continental slope are similar to their outer shelf and upper slope counterparts.

Characterization of Black and Brown Carbon Concentrations and Sources during winter in Beijing

NASA Astrophysics Data System (ADS)

Yan, Caiqing; Liu, Yue; Hansen, Anthony D. A.; Močnik, Griša; Zheng, Mei

2017-04-01

Carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), play important roles in air quality, human health, and climate change. A better understanding of sources of light-absorbing carbonaceous aerosol (including black carbon and brown carbon) is particular critical for formulating emission-based control strategies and reducing uncertainties in current aerosol radiative forcing estimates. Beijing, the capital of China, has experienced serious air pollution problems and high concentrations of carbonaceous aerosols in recent years, especially during heating seasons. During November and December of 2016, several severe haze episodes occurred in Beijing, with hourly average PM2.5 mass concentration up to 400 μg/m3. In this study, concentration levels and sources of black carbon and brown carbon were investigated based on 7-wavelength Aethalometer (AE-33) with combination of other PM2.5 chemical composition information. Contributions of traffic and non-traffic emissions (e.g., coal combustion, biomass burning) were apportioned, and brown carbon was separated from black carbon. Our preliminary results showed that (1) Concentrations of BC were around 5.3±4.2 μg/m3 during the study period, with distinct diurnal variations during haze and non-haze days. (2) Traffic emissions contributed to about 37±17% of total BC, and exhibited higher contributions during non-haze days compared to haze days. (3) Coal combustion was a major source of black carbon and brown carbon in Beijing, which was more significant compared to biomass burning. Sources and the relative contributions to black carbon and brown carbon during haze and non-haze days will be further discussed.

Nitrogen and carbon source-sink relationships in trees at the Himalayan treelines compared with lower elevations.

PubMed

Li, Mai-He; Xiao, Wen-Fa; Shi, Peili; Wang, San-Gen; Zhong, Yong-De; Liu, Xing-Liang; Wang, Xiao-Dan; Cai, Xiao-Hu; Shi, Zuo-Min

2008-10-01

No single hypothesis or theory has been widely accepted for explaining the functional mechanism of global alpine/arctic treeline formation. The present study tested whether the alpine treeline is determined by (1) the needle nitrogen content associated with photosynthesis (carbon gain); (2) a sufficient source-sink ratio of carbon; or (3) a sufficient C-N ratio. Nitrogen does not limit the growth and development of trees studied at the Himalayan treelines. Levels of non-structural carbohydrates (NSC) in trees were species-specific and site-dependent; therefore, the treeline cases studied did not show consistent evidence of source/carbon limitation or sink/growth limitation in treeline trees. However, results of the combined three treelines showed that the treeline trees may suffer from a winter carbon shortage. The source capacity and the sink capacity of a tree influence its tissue NSC concentrations and the carbon balance; therefore, we suggest that the persistence and development of treeline trees in a harsh alpine environment may require a minimum level of the total NSC concentration, a sufficiently high sugar:starch ratio, and a balanced carbon source-sink relationship.

Polysaccharide production by a reduced pigmentation mutant of Aureobasidium pullulans NYS-1.

PubMed

West, T P; Strohfus, B

2001-08-01

To isolate a reduced pigmentation mutant of Aureobasidium pullulans NYS-1 and characterize its cellular pigmentation plus its polysaccharide and biomass production relative to carbon source. Cellular pigmentation, polysaccharide levels and biomass production by the isolated mutant NYSRP-1 were analysed relative to carbon source. Cellular pigmentation of the mutant was lower than its parent strain using either carbon source. The mutant elaborated higher polysaccharide levels on sucrose than on corn syrup. The pullulan content of the polysaccharide synthesized and biomass production by the mutant rose as the carbon source concentration was increased. It is feasible to isolate a reduced pigmentation mutant from strain NYS-1 that exhibits elevated polysaccharide production using corn syrup as a carbon source. The mutant provides an advantage for commercial pullulan production because of its reduced pigmentation and enhanced polysaccharide synthesis.

[Kinetic simulation of enhanced biological phosphorus removal with fermentation broth as carbon source].

PubMed

Zhang, Chao; Chen, Yin-Guang

2013-07-01

As a high-quality carbon source, fermentation broth could promote the phosphorus removal efficiency in enhanced biological phosphorus removal (EBPR). The transformation of substrates in EBPR fed with fermentation broth was well simulated using the modified activated sludge model No. 2 (ASM2) based on the carbon source metabolism. When fermentation broth was used as the sole carbon source, it was found that heterotrophic bacteria acted as a promoter rather than a competitor to the phosphorus accumulating organisms (PAO). When fermentation broth was used as a supplementary carbon source of real municipal wastewater, the wastewater composition was optimized for PAO growth; and the PAO concentration, which was increased by 3.3 times compared to that in EBPR fed with solely real municipal wastewater, accounting for about 40% of the total biomass in the reactor.

The application of UV LEDs for differential optical absorption spectroscopy

NASA Astrophysics Data System (ADS)

Geiko, Pavel P.; Smirnov, Sergey S.; Samokhvalov, Ignatii V.

2018-04-01

Modern UV LEDs represent a potentially very advantageous alternative to thermal light sources, in particular xenon arc lamps, which are the most common light sources in trace gas-analyzers. So, the light-emitting diodes are very attractive for use of as light sources for Long Path Differential Optical Absorption Spectroscopy (DOAS) measurements of trace gases in the open atmosphere. Recent developments in fibre-coupling telescope technology and the availability of ultraviolet light emitting diodes have now allowed us to construct a portable, long path DOAS instrument for use at remote locations and specifically for measuring degassing from active volcanic systems. First of all, we are talking about the measurement of sulphur dioxide, carbon disulphide and, oxides of chlorine and bromine. The parallel measurements of sulfur dioxide using a certified gas analyzer, were conducted and showed good correlation.

Pyrolytic carbon black composite and method of making the same

DOEpatents

Naskar, Amit K.; Paranthaman, Mariappan Parans; Bi, Zhonghe

2016-09-13

A method of recovering carbon black includes the step of providing a carbonaceous source material containing carbon black. The carbonaceous source material is contacted with a sulfonation bath to produce a sulfonated material. The sulfonated material is pyrolyzed to produce a carbon black containing product comprising a glassy carbon matrix phase having carbon black dispersed therein. A method of making a battery electrode is also disclosed.

An audit of the global carbon budget: identifying and reducing sources of uncertainty

NASA Astrophysics Data System (ADS)

Ballantyne, A. P.; Tans, P. P.; Marland, G.; Stocker, B. D.

2012-12-01

Uncertainties in our carbon accounting practices may limit our ability to objectively verify emission reductions on regional scales. Furthermore uncertainties in the global C budget must be reduced to benchmark Earth System Models that incorporate carbon-climate interactions. Here we present an audit of the global C budget where we try to identify sources of uncertainty for major terms in the global C budget. The atmospheric growth rate of CO2 has increased significantly over the last 50 years, while the uncertainty in calculating the global atmospheric growth rate has been reduced from 0.4 ppm/yr to 0.2 ppm/yr (95% confidence). Although we have greatly reduced global CO2 growth rate uncertainties, there remain regions, such as the Southern Hemisphere, Tropics and Arctic, where changes in regional sources/sinks will remain difficult to detect without additional observations. Increases in fossil fuel (FF) emissions are the primary factor driving the increase in global CO2 growth rate; however, our confidence in FF emission estimates has actually gone down. Based on a comparison of multiple estimates, FF emissions have increased from 2.45 ± 0.12 PgC/yr in 1959 to 9.40 ± 0.66 PgC/yr in 2010. Major sources of increasing FF emission uncertainty are increased emissions from emerging economies, such as China and India, as well as subtle differences in accounting practices. Lastly, we evaluate emission estimates from Land Use Change (LUC). Although relative errors in emission estimates from LUC are quite high (2 sigma ~ 50%), LUC emissions have remained fairly constant in recent decades. We evaluate the three commonly used approaches to estimating LUC emissions- Bookkeeping, Satellite Imagery, and Model Simulations- to identify their main sources of error and their ability to detect net emissions from LUC.; Uncertainties in Fossil Fuel Emissions over the last 50 years.

Production of lipopeptide biosurfactants by Bacillus atrophaeus 5-2a and their potential use in microbial enhanced oil recovery.

PubMed

Zhang, Junhui; Xue, Quanhong; Gao, Hui; Lai, Hangxian; Wang, Ping

2016-10-03

Lipopeptides are known as promising microbial surfactants and have been successfully used in enhancing oil recovery in extreme environmental conditions. A biosurfactant-producing strain, Bacillus atrophaeus 5-2a, was recently isolated from an oil-contaminated soil in the Ansai oilfield, Northwest China. In this study, we evaluated the crude oil removal efficiency of lipopeptide biosurfactants produced by B. atrophaeus 5-2a and their feasibility for use in microbial enhanced oil recovery. The production of biosurfactants by B. atrophaeus 5-2a was tested in culture media containing eight carbon sources and nitrogen sources. The production of a crude biosurfactant was 0.77 g L -1 and its surface tension was 26.52 ± 0.057 mN m -1 in a basal medium containing brown sugar (carbon source) and urea (nitrogen source). The biosurfactants produced by the strain 5-2a demonstrated excellent oil spreading activity and created a stable emulsion with paraffin oil. The stability of the biosurfactants was assessed under a wide range of environmental conditions, including temperature (up to 120 °C), pH (2-13), and salinity (0-50 %, w/v). The biosurfactants were found to retain surface-active properties under the extreme conditions. Additionally, the biosurfactants were successful in a test to simulate microbial enhanced oil recovery, removing 90.0 and 93.9 % of crude oil adsorbed on sand and filter paper, respectively. Fourier transform infrared spectroscopy showed that the biosurfactants were a mixture of lipopeptides, which are powerful biosurfactants commonly produced by Bacillus species. The study highlights the usefulness of optimization of carbon and nitrogen sources and their effects on the biosurfactants production and further emphasizes on the potential of lipopeptide biosurfactants produced by B. atrophaeus 5-2a for crude oil removal. The favorable properties of the lipopeptide biosurfactants make them good candidates for application in the bioremediation of oil-contaminated sites and microbial enhanced oil recovery process.

Cultivation of Chlorella vulgaris using different sources of carbon and its impact on lipid production

NASA Astrophysics Data System (ADS)

Fransiscus, Yunus; Purwanto, Edy

2017-05-01

A cultivation process of Chlorella vulgaris has been done in different treatment to investigate the optimum condition for lipid production. Firstly, autotroph and heterotroph condition have been applied to test the significance impact of carbon availability to the growth and lipid production of Chlorella vulgaris. And for the same purpose, heterotroph condition using glucose, fructose and sucrose as carbon sources was independently implemented. The growth rate of Chlorella vulgaris in autotroph condition was much slower than those in heterotroph. The different sources of carbon gave no significant different in the growth pattern, but in term of lipid production it was presented a considerable result. At lower concentration (3 and 6 gr/L) of carbon sources there was only slight different in lipid production level. At higher concentration (12 gr/L) glucose as a carbon source produced the highest result, 60.18% (w/w) compared to fructose and sucrose that produced 27.34% (w/w) and 18.19% (w/w) respectively.

The roles of inoculants' carbon source use in the biocontrol of potato scab disease.

PubMed

Sun, Pingping; Zhao, Xinbei; Shangguan, Nini; Chang, Dongwei; Ma, Qing

2015-04-01

Despite the application of multiple strains in the biocontrol of plant diseases, multistrain inoculation is still constrained by its inconsistency in the field. Nutrients, especially carbons, play an important role in the biocontrol processes. However, little work has been done on the systematic estimation of inoculants' carbon source use on biocontrol efficacies in vivo. In the present study, 7 nonpathogenic Streptomyces strains alone and in different combinations were inoculated as biocontrol agents against the potato scab disease, under field conditions and greenhouse treatments. The influence of the inoculants' carbon source use properties on biocontrol efficacies was investigated. The results showed that increasing the number of inoculated strains did not necessarily result in greater biocontrol efficacy in vivo. However, single strains with higher growth rates or multiple strains with less carbon source competition had positive effects on the biocontrol efficacies. These findings may shed light on optimizing the consistent biocontrol of plant disease with the consideration of inoculants' carbon source use properties.

Carbonate ions and arsenic dissolution by groundwater

USGS Publications Warehouse

Kim, M.-J.; Nriagu, J.; Haack, S.

2000-01-01

Samples of Marshall Sandstone, a major source of groundwater with elevated arsenic levels in southeast Michigan, were exposed to bicarbonate ion under controlled chemical conditions. In particular, effects of pH and redox conditions on arsenic release were evaluated. The release of arsenic from the aquifer rock was strongly related to the bicarbonate concentration in the leaching solution. The results obtained suggest that the carbonation of arsenic sulfide minerals, including orpiment (As2S3) and realgar (As2S2), is an important process in leaching arsenic into groundwater under anaerobic conditions. The arseno-carbonate complexes formed, believed to be As(CO3)2-, As(CO3)(OH)2-, and AsCO3+, are stable in groundwater. The reaction of ferrous ion with the thioarsenite from carbonation process can result in the formation of arsenopyrite which is a common mineral in arsenic-rich aquifers.Samples of Marshall Sandstone, a major source of groundwater with elevated arsenic levels in southeast Michigan, were exposed to bicarbonate ion under controlled chemical conditions. In particular, effects of pH and redox conditions on arsenic release were evaluated. The release of arsenic from the aquifer rock was strongly related to the bicarbonate concentration in the leaching solution. The results obtained suggest that the carbonation of arsenic sulfide minerals, including orpiment (As2S3) and realgar (As2S2), is an important process in leaching arsenic into groundwater under anaerobic conditions. The arseno-carbonate complexes formed, believed to be As(CO3)2-, As(CO3)(OH)2-, and AsCO3+, are stable in groundwater. The reaction of ferrous ion with the thioarsenite from carbonation process can result in the formation of arsenopyrite which is a common mineral in arsenic-rich aquifers.The role of bicarbonate in leaching arsenic into groundwater was investigated by conducting batch experiments using core samples of Marshall Sandstone from southeast Michigan and different bicarbonate solutions. The effects of pH and redox conditions on As dissolution were examined. Results showed that As was not leached significantly out of the Marshall Sandstone samples after 3 d using either deionized water or groundwater, but As was leached efficiently by sodium bicarbonate, potassium bicarbonate, and ferric chloride solutions. The leaching rate with sodium bicarbonate was about 25% higher than that with potassium bicarbonate. The data indicated that bicarbonate ion was involved primarily in As dissolution and that hydroxyl radical ion did not affect As dissolution to any significant degree. The amount of As leached was dependent upon the sodium bicarbonate concentration, increasing with reaction time for each concentration. Significant As leaching was found in the extreme pH ranges of <1.9 and 8.0-10.4. The resulting arseno-carbonate complexes formed were stable in groundwater.

Non-stationary (13)C-metabolic flux ratio analysis.

PubMed

Hörl, Manuel; Schnidder, Julian; Sauer, Uwe; Zamboni, Nicola

2013-12-01

(13)C-metabolic flux analysis ((13)C-MFA) has become a key method for metabolic engineering and systems biology. In the most common methodology, fluxes are calculated by global isotopomer balancing and iterative fitting to stationary (13)C-labeling data. This approach requires a closed carbon balance, long-lasting metabolic steady state, and the detection of (13)C-patterns in a large number of metabolites. These restrictions mostly reduced the application of (13)C-MFA to the central carbon metabolism of well-studied model organisms grown in minimal media with a single carbon source. Here we introduce non-stationary (13)C-metabolic flux ratio analysis as a novel method for (13)C-MFA to allow estimating local, relative fluxes from ultra-short (13)C-labeling experiments and without the need for global isotopomer balancing. The approach relies on the acquisition of non-stationary (13)C-labeling data exclusively for metabolites in the proximity of a node of converging fluxes and a local parameter estimation with a system of ordinary differential equations. We developed a generalized workflow that takes into account reaction types and the availability of mass spectrometric data on molecular ions or fragments for data processing, modeling, parameter and error estimation. We demonstrated the approach by analyzing three key nodes of converging fluxes in central metabolism of Bacillus subtilis. We obtained flux estimates that are in agreement with published results obtained from steady state experiments, but reduced the duration of the necessary (13)C-labeling experiment to less than a minute. These results show that our strategy enables to formally estimate relative pathway fluxes on extremely short time scale, neglecting cellular carbon balancing. Hence this approach paves the road to targeted (13)C-MFA in dynamic systems with multiple carbon sources and towards rich media. © 2013 Wiley Periodicals, Inc.

[Effects of furfural on the growth and lipid production of oleaginous yeast Rhodotorula glutinis].

PubMed

Yong, Zihan; Zhang, Xu; Tan, Tianwei

2015-10-01

In order to illustrate the effects of furfural, one of the most common inhibitory compounds in lignocellulosic hydrolysate, on oleaginous yeast Rhodotorula glutinis, we investigated the effects of different concentrations of furfural (0.1, 0.4, 0.6 and 1.5 g/L) on the biomass and lipid production of R. glutinis, as well as the effects of 1.0 g/L furfural on the utilization of glucose and xylose. Results showed that: when the furfural concentration reached 1.5 g/L, the lag phrase time was extended to 96 h, and the residual glucose was up to 17.7 g/L, with maximum biomass of only 6.6 g/L, which accounted for 47% of that in the basic medium (furfural-free), and the corresponding lipid content was reduced about 50%. Furfural showed lighter inhibitory degree on R. glutinis when xylose acted as the carbon source than glucose was the carbon source; more C18 fatty acids or unsaturated C18 fatty acids were generated in the presence of furfural.

Extraction and Esterification of Low-Titer Short-Chain Volatile Fatty Acids from Anaerobic Fermentation with Ionic Liquids.

PubMed

Andersen, Stephen J; Berton, Jan K E T; Naert, Pieter; Gildemyn, Sylvia; Rabaey, Korneel; Stevens, Christian V

2016-08-23

Ionic liquids can both act as a solvent and mediate esterification to valorize low-titer volatile fatty acids and generate organic solvents from renewable carbon sources including biowaste and CO2 . In this study, four phosphonium ionic liquids were tested for single-stage extraction of acetic acid from a dilute stream and esterification to ethyl acetate with added ethanol and heat. The esterification proceeded with a maximum conversion of 85.9±1.3 % after 30 min at 75 °C at a 1:1 stoichiometric ratio of reactants. Extraction and esterification can be tailored using mixed-anion ionic liquids; this is demonstrated herein using a common trihexyl(tetradecyl)phosphonium cation and a mixed chloride and bis(trifluoromethylsulfonyl)imide anion ionic liquid. As a further proof-of-concept, ethyl acetate was generated from an ionic liquid-driven esterification of an acetic acid extractant generated using CO2 as the only carbon source by microbial electrosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improved artificial saliva for studying the cariogenic effect of carbohydrates.

PubMed

Björklund, Marika; Ouwehand, Arthur C; Forssten, Sofia D

2011-07-01

Saliva is a complex fluid that possesses many important functions regarding oral health. Many in vitro studies require relatively large quantities of saliva. While natural saliva would be the material of choice, it is difficult to obtain in sufficient quantities and varies in composition. Substitutes mimicking the physicochemical properties of saliva have been developed, but these are not appropriate to study the growth of mutans streptococci. Brain Heart Infusion (BHI) has been commonly used for this, but this medium is richer in nutrients than saliva. We therefore developed artificial saliva (AS) with nutrient levels resembling those in natural saliva as a substitute for natural human saliva (HS) to study the influence of different carbon sources on mutans streptococci growth. Growth of a wild-type Streptococcus mutans strain and S. mutans ATCC 15175 in BHI, HS, and AS was monitored anaerobically. Growth of S. mutans in the modified AS was very similar to the growth in HS, both in the absence and presence of different carbon sources. We therefore conclude that the developed AS is suitable for in vitro tests on S. mutans growth.

Carbon Monoxide Epidemic Among Immigrant Populations: King County, Washington, 2006

PubMed Central

Kwan-Gett, Tao; Hampson, Neil B.; Baer, Atar; Shusterman, Dennis; Shandro, Jamie R.; Duchin, Jeffrey S.

2009-01-01

Objectives. We investigated an outbreak of carbon monoxide (CO) poisoning after a power outage to determine its extent, identify risk factors, and develop prevention measures. Methods. We reviewed medical records and medical examiner reports of patients with CO poisoning or related symptoms during December 15 to 24, 2006. We grouped patients into households exposed concurrently to a single source of CO. Results. Among 259 patients with CO poisoning, 204 cases were laboratory confirmed, 37 were probable, 10 were suspected, and 8 were fatal. Of 86 households studied, 58% (n = 50) were immigrant households from Africa (n = 21), Asia (n = 15), Latin America (n = 10), and the Middle East (n = 4); 34% (n = 29) were US-born households. One percent of households was European (n = 1), and the origin for 7% (n = 6) was unknown. Charcoal was the most common fuel source used among immigrant households (82%), whereas liquid fuel was predominant among US-born households (34%). Conclusions. Educational campaigns to prevent CO poisoning should consider immigrants’ cultural practices and languages and specifically warn against burning charcoal indoors and incorrect ventilation of gasoline- or propane-powered electric generators. PMID:19608962

USE OF FATTY ACID STABLE CARBON ISOTOPE RATIO TO INDICATE MICROBIAL CARBON SOURCE IN TROPICAL SOILS

EPA Science Inventory

We use measurements of the concentration and stable carbon isotope ratio of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels, broad microbial community structure, and microbial carbon source. For studies of soil o...

Management of Philippine tropical forests: Implications to global warming

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

Lasco, R.D.

1997-12-31

The first part of the paper presents the massive changes in tropical land management in the Philippines as a result of a {open_quotes}paradigm shift{close_quotes} in forestry. The second part of the paper analyzes the impacts of the above management strategies on global warming, in general, preserved forests are neither sinks not sources of greenhouse gasses (GHG). Reforestation activities are primarily net sinks of carbon specially the use of fast growing reforestation species. Estimates are given for the carbon-sequestering ability of some commonly used species. The last part of the paper policy recommendations and possible courses of action by the governmentmore » to maximize the role of forest lands in the mitigation of global warming. Private sector initiatives are also explored.« less

Monolithic Carbide-Derived Carbon Films for Micro-Supercapacitors

NASA Astrophysics Data System (ADS)

Chmiola, John; Largeot, Celine; Taberna, Pierre-Louis; Simon, Patrice; Gogotsi, Yury

2010-04-01

Microbatteries with dimensions of tens to hundreds of micrometers that are produced by common microfabrication techniques are poised to provide integration of power sources onto electronic devices, but they still suffer from poor cycle lifetime, as well as power and temperature range of operation issues that are alleviated with the use of supercapacitors. There have been a few reports on thin-film and other micro-supercapacitors, but they are either too thin to provide sufficient energy or the technology is not scalable. By etching supercapacitor electrodes into conductive titanium carbide substrates, we demonstrate that monolithic carbon films lead to a volumetric capacity exceeding that of micro- and macroscale supercapacitors reported thus far, by a factor of 2. This study also provides the framework for integration of high-performance micro-supercapacitors onto a variety of devices.

Monolithic carbide-derived carbon films for micro-supercapacitors.

PubMed

Chmiola, John; Largeot, Celine; Taberna, Pierre-Louis; Simon, Patrice; Gogotsi, Yury

2010-04-23

Microbatteries with dimensions of tens to hundreds of micrometers that are produced by common microfabrication techniques are poised to provide integration of power sources onto electronic devices, but they still suffer from poor cycle lifetime, as well as power and temperature range of operation issues that are alleviated with the use of supercapacitors. There have been a few reports on thin-film and other micro-supercapacitors, but they are either too thin to provide sufficient energy or the technology is not scalable. By etching supercapacitor electrodes into conductive titanium carbide substrates, we demonstrate that monolithic carbon films lead to a volumetric capacity exceeding that of micro- and macroscale supercapacitors reported thus far, by a factor of 2. This study also provides the framework for integration of high-performance micro-supercapacitors onto a variety of devices.

The effect of structure and a secondary carbon source on the microbial degradation of chlorophenoxy acids.

PubMed

Evangelista, S; Cooper, D G; Yargeau, V

2010-05-01

Pseudomonas putida, Aspergillus niger, Bacillus subtilis, Pseudomonas fluorescens, Sphingomonas herbicidovorans and Rhodococcus rhodochrous growing on glucose in a medium containing one of three chlorophenoxy acids at a concentration of 0.1 g L(-1) (clofibric acid, (R)-2-(4-chloro-2-methylphenoxy)propionic acid (mecoprop or MCPP) and 4-chloro-2-methylphenoxyacetic acid (MCPA)) degraded these compounds to varying degrees; from nonmeasurable to almost complete removal. These results with the addition of glucose (2.5 g L(-1)) as an easy to use carbon source indicated the formation of metabolites different from results reported in the literature for growth studies in which the chlorophenoxy acid was the sole carbon source. The metabolite, 4-chloro-2-methylphenol, which had been reported previously, was only observed in trace amounts for MCPP and MCPA in the presence of S. herbicidovorans and glucose. In addition, three other compounds (M1, M3 and M4) were observed. It is suggested that these unidentified metabolites resulted from ring opening of the metabolite 4-chloro-2-methylphenol (M2). The rate of biodegradation of the chlorophenoxy acids was influenced by the degree of steric hindrance adjacent to the internal oxygen bond common to all three compounds. The most hindered compound, clofibric acid, was converted to ethyl clofibrate by R. rhodochrous but was not degraded by any microorganisms studied. The more accessible internal oxygen bonds of the other two chlorophenoxy acids, MCPP and MCPA, were readily broken by S. herbicidovorans. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Production of Buttery-Odor Compounds and Transcriptome Response in Leuconostoc gelidum subsp. gasicomitatum LMG18811T during Growth on Various Carbon Sources

PubMed Central

Vesterinen, Sanna; Parshintsev, Jevgeni; Johansson, Per; Riekkola, Marja-Liisa; Björkroth, Johanna

2014-01-01

Leuconostoc gelidum subsp. gasicomitatum is a common spoilage bacterium in meat products packaged under oxygen-containing modified atmospheres. Buttery off-odors related to diacetyl/acetoin formation are frequently associated with the spoilage of these products. A whole-genome microarray study, together with gas chromatography (GC)-mass spectrometry (MS) analyses of the pathway end products, was performed to investigate the transcriptome response of L. gelidum subsp. gasicomitatum LMG18811T growing on semidefined media containing glucose, ribose, or inosine, which are essential carbon sources in meat. Generally, the gene expression patterns with ribose and inosine were quite similar, indicating that catabolism of ribose and nucleosides is closely linked. Diacetyl/acetoin concentrations as high as 110 or 470 μM were measured when growth was based on inosine or ribose, respectively. The gene expression results for pyruvate metabolism (upregulation of α-acetolactate synthase, downregulation of l-lactate dehydrogenase and pyruvate dehydrogenase) were as expected when diacetyl and acetoin were the end products. No diacetyl production (<7.5 μM) was detected with the glucose-containing medium, even though the cell counts of LMG18811T was 6 or 10 times higher than that on inosine or ribose, respectively. Although glucose was the most effective carbon source for the growth of L. gelidum subsp. gasicomitatum, utilization of inosine and ribose resulted in the production of the unwanted buttery-odor compounds. These results increase our understanding of which compounds are likely to enhance the formation of buttery odors during meat spoilage caused by L. gelidum subsp. gasicomitatum. PMID:25548057

IMPROVING SOURCE PROFILES AND APPORTIONMENT OF COMBUSTION SOURCES USING THERMAL CARBON FRACTIONS IN MULTIVARIATE RECEPTOR MODELS

EPA Science Inventory

The purpose of this study was to improve combustion source profiles and apportionment of a PM2.5 urban aerosol by using 7 individual organic and elemental carbon thermal fractions in place of total organic and elemental carbon. This study used 3 years (96-99) of speciated data...

The Effect of Carbon Source and Fluoride Concentrations in the "Streptococcus Mutans" Biofilm Formation

ERIC Educational Resources Information Center

Paulino, Tony P.; Andrade, Ricardo O.; Bruschi-Thedei, Giuliana C. M.; Thedei, Geraldo, Jr.; Ciancaglini, Pietro

2004-01-01

The main objective of this class experiment is to show the influence of carbon source and of different fluoride concentrations on the biofilm formation by the bacterium "Streptococcus mutans." The observation of different biofilm morphology as a function of carbon source and fluoride concentration allows an interesting discussion regarding the…

Residential carbon monoxide poisoning from motor vehicles.

PubMed

Hampson, Neil B

2011-01-01

Although morbidity and mortality from accidental carbon monoxide (CO) poisoning are high in the United States, identification of common but poorly recognized sources should help prevention efforts. The study aimed to describe CO poisoning of home occupants due to a vehicle left running in an attached garage. News stories reporting incidents of US CO poisoning were collected daily from March 2007 to September 2009 via a news.Google.com search and data extracted. Patients were individuals reported in the media to have been poisoned with CO in their home by a vehicle running in the attached garage. Main outcome measures were frequency of occurrence, geographic distribution, patient demographics, and mortality. Of 837 CO poisoning incidents reported in US news media over 2 and a half years, 59 (8%) were the result of a vehicle left running in the garage. The elderly were disproportionately affected, with incidents most common in states with larger elderly populations and 29% of cases with age specified occurring in individuals older than 80 years. Among those older than 80 years, 15 of 17 were found dead at the scene. Residential CO poisoning from a vehicle running in the garage is common, disproportionately affects the elderly, has a high mortality rate, and should be preventable with a residential CO alarm. Copyright © 2011 Elsevier Inc. All rights reserved.

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

Wear, Jr., John Edmund

The objective of this study was to examine the hypothesis that select functional groups of bacteria from pristine sites have an innate ability to degrade synthetic aromatics that often contaminate groundwater environments,due to exposure to naturally occurring recalcitrant aromatics in their environment. This study demonstrates that subsurface microbial communities are capable of utilizing lignin and humic acid breakdown products. Utilizers of these compounds were found to be present in most all the wells tested. Even the deepest aquifer tested had utilizers present for all six of the aromatics tested. Highest counts for the aromatics tested were observed with the naturallymore » occurring breakdown products of either lignin or humic acid. Carboxylic acids were found to be an important sole carbon source for groundwater bacteria possibly explained by the fact that they are produced by the oxidative cleavage of aromatic ring structures. The carbohydrate sole carbon sources that demonstrated the greatest densities were ones commonly associated with humics. This study indicates that utilization of naturally occurring aromatic compounds in the subsurface is an important nutritional source for groundwater bacteria. In addition, it suggests that adaptation to naturally occurring recalcitrant substrates is the origin of degradative pathways for xenobiotic compounds with analogous structure. This work has important implications for in situ bioremediation as a method of environmental cleanup.« less

Effect of CO2 on NADH production of denitrifying microbes via inhibiting carbon source transport and its metabolism.

PubMed

Wan, Rui; Chen, Yinguang; Zheng, Xiong; Su, Yinglong; Huang, Haining

2018-06-15

The potential effect of CO 2 on environmental microbes has drawn much attention recently. As an important section of the nitrogen cycle, biological denitrification requires electron donor to reduce nitrogen oxide. Nicotinamide adenine dinucleotide (NADH), which is formed during carbon source metabolism, is a widely reported electron donor for denitrification. Here we studied the effect of CO 2 on NADH production and carbon source utilization in the denitrifying microbe Paracoccus denitrificans. We observed that NADH level was decreased by 45.5% with the increase of CO 2 concentration from 0 to 30,000ppm, which was attributed to the significantly decreased utilization of carbon source (i.e., acetate). Further study showed that CO 2 inhibited carbon source utilization because of multiple negative influences: (1) suppressing the growth and viability of denitrifier cells, (2) weakening the driving force for carbon source transport by decreasing bacterial membrane potential, and (3) downregulating the expression of genes encoding key enzymes involved in intracellular carbon metabolism, such as citrate synthase, aconitate hydratase, isocitrate dehydrogenase, succinate dehydrogenase, and fumarate reductase. This study suggests that the inhibitory effect of CO 2 on NADH production in denitrifiers might deteriorate the denitrification performance in an elevated CO 2 climate scenario. Copyright © 2018 Elsevier B.V. All rights reserved.

The application of carbon-14 analyses to the source apportionment of atmospheric carbonaceous particulate matter: a review.

PubMed

Heal, Mathew R

2014-01-01

Organic carbon (OC) and elemental carbon (EC) together constitute a substantial proportion of airborne particulate matter (PM). Insight into the sources of this major contributor to PM is important for policies to mitigate the impact of PM on human health and climate change. In recent years measurement of the abundance of the radioisotope of carbon ((14)C) in samples of PM by accelerator mass spectrometry has been used to help quantify the relative contributions from sources of fossil carbon and contemporary carbon. This review provides an introduction to the different sources of carbon within PM and the role of (14)C measurements, a description of the preparation of PM samples and of the instrumentation used to quantify (14)C, and a summary of the results and source apportionment methods reported in published studies since 2004. All studies report a sizable fraction of the carbonaceous PM as of non-fossil origin. Even for PM collected in urban locations, the proportions of non-fossil carbon generally exceed 30%; typically the proportion in urban background locations is around 40-60% depending on the local influence of biomass burning. Where values have been measured directly, proportions of non-fossil carbon in EC are lower than in OC, reflecting the greater contribution of fossil-fuel combustion to EC and the generally small sources of contemporary EC. Detailed source apportionment studies point to important contributions from biogenic-derived secondary OC, consistent with other evidence of a ubiquitous presence of heavily oxidized background secondary OC. The review concludes with some comments on current issues and future prospects, including progress towards compound-class and individual-compound-specific (14)C analyses.

Selection and evaluation of reference genes for RT-qPCR expression studies on Burkholderia tropica strain Ppe8, a sugarcane-associated diazotrophic bacterium grown with different carbon sources or sugarcane juice.

PubMed

da Silva, Paula Renata Alves; Vidal, Marcia Soares; de Paula Soares, Cleiton; Polese, Valéria; Simões-Araújo, Jean Luís; Baldani, José Ivo

2016-11-01

Among the members of the genus Burkholderia, Burkholderia tropica has the ability to fix nitrogen and promote sugarcane plant growth as well as act as a biological control agent. There is little information about how this bacterium metabolizes carbohydrates as well as those carbon sources found in the sugarcane juice that accumulates in stems during plant growth. Reverse transcription quantitative PCR (RT-qPCR) can be used to evaluate changes in gene expression during bacterial growth on different carbon sources. Here we tested the expression of six reference genes, lpxC, gyrB, recA, rpoA, rpoB, and rpoD, when cells were grown with glucose, fructose, sucrose, mannitol, aconitic acid, and sugarcane juice as carbon sources. The lpxC, gyrB, and recA were selected as the most stable reference genes based on geNorm and NormFinder software analyses. Validation of these three reference genes during strain Ppe8 growth on the same carbon sources showed that genes involved in glycogen biosynthesis (glgA, glgB, glgC) and trehalose biosynthesis (treY and treZ) were highly expressed when Ppe8 was grown in aconitic acid relative to other carbon sources, while otsA expression (trehalose biosynthesis) was reduced with all carbon sources. In addition, the expression level of the ORF_6066 (gluconolactonase) gene was reduced on sugarcane juice. The results confirmed the stability of the three selected reference genes (lpxC, gyrB, and recA) during the RT-qPCR and also their robustness by evaluating the relative expression of genes involved in glycogen and trehalose biosynthesis when strain Ppe8 was grown on different carbon sources and sugarcane juice.

Strains of the soil fungus Mortierella show different degradation potentials for the phenylurea herbicide diuron.

PubMed

Ellegaard-Jensen, Lea; Aamand, Jens; Kragelund, Birthe B; Johnsen, Anders H; Rosendahl, Søren

2013-11-01

Microbial pesticide degradation studies have until now mainly focused on bacteria, although fungi have also been shown to degrade pesticides. In this study we clarify the background for the ability of the common soil fungus Mortierella to degrade the phenylurea herbicide diuron. Diuron degradation potentials of five Mortierella strains were compared, and the role of carbon and nitrogen for the degradation process was investigated. Results showed that the ability to degrade diuron varied greatly among the Mortierella strains tested, and the strains able to degrade diuron were closely related. Degradation of diuron was fastest in carbon and nitrogen rich media while suboptimal nutrient levels restricted degradation, making it unlikely that Mortierella utilize diuron as carbon or nitrogen sources. Degradation kinetics showed that diuron degradation was followed by formation of the metabolites 1-(3,4-dichlorophenyl)-3-methylurea, 1-(3,4-dichlorophenyl)urea and an hitherto unknown metabolite suggested to be 1-(3,4-dichlorophenyl)-3-methylideneurea.

Controlling optics contamination at the PolLux STXM

NASA Astrophysics Data System (ADS)

Watts, B.; Pilet, N.; Sarafimov, B.; Witte, K.; Raabe, J.

2018-04-01

Contamination of X-ray mirror surfaces by carbon is a common issue that can significantly degrade the optical performance of the instrument. The effects can be severe at photon energies near the carbon K-edge (ca. 300 eV), where the X-rays are strongly attenuated, but also significant at higher photon energies where the carbon coating affects the reflectivity and surface shape of the mirrors. [1] The Swiss Light Source has typically relied on in-situ plasma cleaning to control mirror contamination and the PolLux scanning transmission X-ray microscopy (STXM) beamline has also been employing further contamination reduction strategies in recent years. In particular, in 2014 we installed a 1×10‑8 mbar background pressure of O2 on the PolLux first mirror chamber. We present a history of efforts to control optical contamination at the PolLux beamline and report on the observed efficiencies of the different processes employed both for the in-vacuum optics and critical components of the frequently vented STXM experiment chamber.

Calcium carbonate does not affect nilotinib pharmacokinetics in healthy volunteers.

PubMed

Tawbi, Hussein A; Tran, An L; Christner, Susan M; Lin, Yan; Johnson, Matthew; Mowrey, Emily; Appleman, Leonard R; Stoller, Ronald; Miller, Brian M; Egorin, Merrill J; Beumer, Jan H

2013-11-01

Gastric upset is a common side effect of nilotinib therapy, and calcium carbonate is frequently used concomitantly, either as antacid or as calcium supplementation. With the increasing number of oral agents in cancer therapy, oral drug-drug interactions are becoming more relevant. Nilotinib has already been shown to be absorbed to a much lesser extent when co-administered with proton pump inhibitors. Because exposure to sub-therapeutic concentrations of anticancer drugs such as nilotinib may result in selection of resistant clones and ultimately relapse, we studied the effect of a calcium carbonate supplement (Tums Ultra 1000®) on nilotinib pharmacokinetics. Calcium carbonate may be co-administered with nilotinib without significantly affecting the pharmacokinetics of nilotinib and potentially impacting efficacy. Nilotinib is a second-generation oral tyrosine kinase inhibitor with superior efficacy compared with imatinib mesylate in the treatment for chronic phase chronic myelogenous leukemia. Calcium carbonate is commonly used as a source of calcium supplementation or as antacid to ameliorate the gastrointestinal side effects associated with nilotinib, which could have unknown effects on nilotinib absorption. The purpose of this study was to provide information on the effect of calcium carbonate on the PK of nilotinib in healthy volunteers. Healthy subjects were enrolled in a two-period, open-label, single-institution, randomized, cross-over, fixed-schedule study. In one period, each subject received 400 mg of nilotinib p.o. In the other period, 4,000 mg of calcium carbonate (4 X Tums Ultra 1000®) was administered p.o. 15 min prior to the nilotinib dose. Plasma samples were collected at specified timepoints, concentrations of nilotinib were quantitated by LC-MS, and data were analyzed non-compartmentally. Eleven subjects were evaluable. Calcium supplementation did not significantly affect nilotinib pharmacokinetic parameters including area under the plasma concentration versus time curve (18.4 μg/mL h alone vs. 16.9 μg/mL h with calcium carbonate, p = 0.83; 80 % power); maximum plasma concentration (C(max)) (0.670 μg/mL alone vs. 6.18 μg/mL with calcium carbonate, p = 0.97); or half-life (18.9 h alone vs. 17.2 h with calcium carbonate, p = 0.18). Our results indicate that the use of calcium carbonate does not significantly affect nilotinib pharmacokinetics.

Use of food waste-recycling wastewater as an alternative carbon source for denitrification process: A full-scale study.

PubMed

Kim, Eunji; Shin, Seung Gu; Jannat, Md Abu Hanifa; Tongco, Jovale Vincent; Hwang, Seokhwan

2017-12-01

Using organic wastes as an alternative to commercial carbon sources could be beneficial by reducing costs and environmental impacts. In this study, food waste-recycling wastewater (FRW) was evaluated as an alternative carbon source for biological denitrification over a period of seven months in a full-scale sewage wastewater treatment plant. The denitrification performance was stable with a mean nitrate removal efficiency of 97.2%. Propionate was initially the most persistent volatile fatty acid, but was completely utilized after 19days. Eubacteriacea, Saprospiraceae, Rhodocyclaceae and Comamonadaceae were the major bacterial families during FRW treatment and were regarded as responsible for hydrolysis (former two) and nitrate removal (latter two) of FRW. These results demonstrate that FRW can be an effective external carbon source; process stabilization was linked to the acclimation and function of bacterial populations to the change of carbon source. Copyright © 2017 Elsevier Ltd. All rights reserved.

Review: role of carbon sources for in vitro plant growth and development.

PubMed

Yaseen, Mehwish; Ahmad, Touqeer; Sablok, Gaurav; Standardi, Alvaro; Hafiz, Ishfaq Ahmad

2013-04-01

In vitro plant cells, tissues and organ cultures are not fully autotrophic establishing a need for carbohydrates in culture media to maintain the osmotic potential, as well as to serve as energy and carbon sources for developmental processes including shoot proliferation, root induction as well as emission, embryogenesis and organogenesis, which are highly energy demanding developmental processes in plant biology. A variety of carbon sources (both reducing and non-reducing) are used in culture media depending upon genotypes and specific stages of growth. However, sucrose is most widely used as a major transport-sugar in the phloem sap of many plants. In micropropagation systems, morphogenetic potential of plant tissues can greatly be manipulated by varying type and concentration of carbon sources. The present article reviews the past and current findings on carbon sources and their sustainable utilization for in vitro plant tissue culture to achieve better growth rate and development.

High CO2 subsurface environment enriches for novel microbial lineages capable of autotrophic carbon fixation

NASA Astrophysics Data System (ADS)

Probst, A. J.; Jerett, J.; Castelle, C. J.; Thomas, B. C.; Sharon, I.; Brown, C. T.; Anantharaman, K.; Emerson, J. B.; Hernsdorf, A. W.; Amano, Y.; Suzuki, Y.; Tringe, S. G.; Woyke, T.; Banfield, J. F.

2015-12-01

Subsurface environments span the planet but remain little understood from the perspective of the capacity of the resident organisms to fix CO2. Here we investigated the autotrophic capacity of microbial communities in range of a high-CO2 subsurface environments via analysis of 250 near-complete microbial genomes (151 of them from distinct species) that represent the most abundant organisms over a subsurface depth transect. More than one third of the genomes belonged to the so-called candidate phyla radiation (CPR), which have limited metabolic capabilities. Approximately 30% of the community members are autotrophs that comprise 70% of the microbiome with metabolism likely supported by sulfur and nitrogen respiration. Of the carbon fixation pathways, the Calvin Benson Basham Cycle was most common, but the Wood-Ljungdhal pathway was present in the greatest phylogenetic diversity of organisms. Unexpectedly, one organism from a novel phylum sibling to the CPR is predicted to fix carbon by the reverse TCA cycle. The genome of the most abundant organism, an archaeon designated "Candidatus Altiarchaeum hamiconexum", was also found in subsurface samples from other continents including Europe and Asia. The archaeon was proven to be a carbon fixer using a novel reductive acetyl-CoA pathway. These results provide evidence that carbon dioxide is the major carbon source in these environments and suggest that autotrophy in the subsurface represents a substantial carbon dioxide sink affecting the global carbon cycle.

Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS).

PubMed

Pramanick, Bidhan; Martinez-Chapa, Sergio O; Madou, Marc; Hwang, Hyundoo

2017-06-17

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long and hollow glassy carbon microfibers derived from human hairs is introduced. The long and hollow carbon structures were made by the pyrolysis of human hair at 900 °C in a N2 atmosphere. The morphology and chemical composition of natural and pyrolyzed human hairs were investigated using scanning electron microscopy (SEM) and electron-dispersive X-ray spectroscopy (EDX), respectively, to estimate the physical and chemical changes due to pyrolysis. Raman spectroscopy was used to confirm the glassy nature of the carbon microstructures. Pyrolyzed hair carbon was introduced to modify screen-printed carbon electrodes ; the modified electrodes were then applied to the electrochemical sensing of dopamine and ascorbic acid. Sensing performance of the modified sensors was improved as compared to the unmodified sensors. To obtain the desired carbon structure design, carbon micro-/nanoelectromechanical system (C-MEMS/C-NEMS) technology was developed. The most common C-MEMS/C-NEMS fabrication process consists of two steps: (i) the patterning of a carbon-rich base material, such as a photosensitive polymer, using photolithography; and (ii) carbonization through the pyrolysis of the patterned polymer in an oxygen-free environment. The C-MEMS/NEMS process has been widely used to develop microelectronic devices for various applications, including in micro-batteries, supercapacitors, glucose sensors, gas sensors, fuel cells, and triboelectric nanogenerators. Here, recent developments of a high-aspect ratio solid and hollow carbon microstructures with SU8 photoresists are discussed. The structural shrinkage during pyrolysis was investigated using confocal microscopy and SEM. Raman spectroscopy was used to confirm the crystallinity of the structure, and the atomic percentage of the elements present in the material before and after pyrolysis was measured using EDX.

Assessment of policy impacts on carbon capture and sequestration and bioenergy for U.S.' coal and natural gas power plants

NASA Astrophysics Data System (ADS)

Spokas, K.; Patrizio, P.; Leduc, S.; Mesfun, S.; Kraxner, F.

2017-12-01

Reducing electricity-sector emissions relies heavily on countries' abilities to either transition away from carbon-intensive energy generation or to sequester its resultant emissions with carbon capture and storage (CCS) technologies. The use of biomass energy technologies in conjunction with carbon capture and sequestration (BECCS) presents the opportunity for net reductions in atmospheric carbon dioxide. In this study, we investigate the limitations of several common policy mechanisms to incentivize the deployment of BECCS using the techno-economic spatial optimization model BeWhere (www.iiasa.ac.at/bewhere). We consider a set of coal and natural gas power plants in the United States (U.S.) selected using a screening process that considers capacity, boiler age, and capacity factor for electricity-generation units from the EPA 2014 eGRID database. The set makes up 470 GW of generation, and produces 8,400 PJ and 2.07 GtCO2 annually. Co-firing up to 15% for coal power plants is considered, using woody-biomass residues sourced from certified and managed U.S. forests obtained from the G4M (www.iiasa.ac.at/g4m) and GeoWiki (www.geo-wiki.org) database. Geologic storage is considered with injectivity and geomechanical limitations to ensure safe storage. Costs are minimized under two policy mechanisms: a carbon tax and geologic carbon sequestration credits, such as the Q45 credits. Results show that the carbon tax scenario incentivizes co-firing at low to medium carbon taxes, but is replaced by CCS at higher tax values. Carbon taxes do not strongly incentivize BECCS, as negative emissions associated with sequestering carbon content are not accounted as revenue. On the other hand, carbon credit scenarios result in significant CCS deployment, but lack any incentive for co-firing.

Microbial production of multi-carbon chemicals and fuels from water and carbon dioxide using electric current

DOEpatents

Lovley, Derek R; Nevin, Kelly

2015-11-03

The invention provides systems and methods for generating organic compounds using carbon dioxide as a source of carbon and electrical current as an energy source. In one embodiment, a reaction cell is provided having a cathode electrode and an anode electrode that are connected to a source of electrical power, and which are separated by a permeable membrane. A biological film is provided on the cathode. The biological film comprises a bacterium that can accept electrons and that can convert carbon dioxide to a carbon-bearing compound and water in a cathode half-reaction. At the anode, water is decomposed to free molecular oxygen and solvated protons in an anode half-reaction. The half-reactions are driven by the application of electrical current from an external source. Compounds that have been produced include acetate, butanol, 2-oxobutyrate, propanol, ethanol, and formate.

Microbial production of multi-carbon chemicals and fuels from water and carbon dioxide using electric current

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

Lovley, Derek R.; Nevin, Kelly P.

The invention provides systems and methods for generating organic compounds using carbon dioxide as a source of carbon and electrical current as an energy source. In one embodiment, a reaction cell is provided having a cathode electrode and an anode electrode that are connected to a source of electrical power, and which are separated by a permeable membrane. A biological film is provided on the cathode. The biological film comprises a bacterium that can accept electrons and that can convert carbon dioxide to a carbon-bearing compound and water in a cathode half-reaction. At the anode, water is decomposed to freemore » molecular oxygen and solvated protons in an anode half-reaction. The half-reactions are driven by the application of electrical current from an external source. Compounds that have been produced include acetate, butanol, 2-oxobutyrate, propanol, ethanol, and formate.« less

USE OF STABLE CARBON ISOTOPE RATIOS OF FATTY ACIDS TO EVALUATE MICROBIAL CARBON SOURCES IN TERRESTRIAL ENVIRONMENTS

EPA Science Inventory

We use measurements of the concentration and stable carbon isotopic ratio (D 13C) of individual microbial phospholipid fatty acids (PLFAs) in soils as indicators of live microbial biomass levels and microbial carbon source. We found that intensive sugar cane cultivation leads to ...

CASSIA--a dynamic model for predicting intra-annual sink demand and interannual growth variation in Scots pine.

PubMed

Schiestl-Aalto, Pauliina; Kulmala, Liisa; Mäkinen, Harri; Nikinmaa, Eero; Mäkelä, Annikki

2015-04-01

The control of tree growth vs environment by carbon sources or sinks remains unresolved although it is widely studied. This study investigates growth of tree components and carbon sink-source dynamics at different temporal scales. We constructed a dynamic growth model 'carbon allocation sink source interaction' (CASSIA) that calculates tree-level carbon balance from photosynthesis, respiration, phenology and temperature-driven potential structural growth of tree organs and dynamics of stored nonstructural carbon (NSC) and their modifying influence on growth. With the model, we tested hypotheses that sink demand explains the intra-annual growth dynamics of the meristems, and that the source supply is further needed to explain year-to-year growth variation. The predicted intra-annual dimensional growth of shoots and needles and the number of cells in xylogenesis phases corresponded with measurements, whereas NSC hardly limited the growth, supporting the first hypothesis. Delayed GPP influence on potential growth was necessary for simulating the yearly growth variation, indicating also at least an indirect source limitation. CASSIA combines seasonal growth and carbon balance dynamics with long-term source dynamics affecting growth and thus provides a first step to understanding the complex processes regulating intra- and interannual growth and sink-source dynamics. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

A mixing-model approach to quantifying sources of organic matter to salt marsh sediments

NASA Astrophysics Data System (ADS)

Bowles, K. M.; Meile, C. D.

2010-12-01

Salt marshes are highly productive ecosystems, where autochthonous production controls an intricate exchange of carbon and energy among organisms. The major sources of organic carbon to these systems include 1) autochthonous production by vascular plant matter, 2) import of allochthonous plant material, and 3) phytoplankton biomass. Quantifying the relative contribution of organic matter sources to a salt marsh is important for understanding the fate and transformation of organic carbon in these systems, which also impacts the timing and magnitude of carbon export to the coastal ocean. A common approach to quantify organic matter source contributions to mixtures is the use of linear mixing models. To estimate the relative contributions of endmember materials to total organic matter in the sediment, the problem is formulated as a constrained linear least-square problem. However, the type of data that is utilized in such mixing models, the uncertainties in endmember compositions and the temporal dynamics of non-conservative entitites can have varying affects on the results. Making use of a comprehensive data set that encompasses several endmember characteristics - including a yearlong degradation experiment - we study the impact of these factors on estimates of the origin of sedimentary organic carbon in a saltmarsh located in the SE United States. We first evaluate the sensitivity of linear mixing models to the type of data employed by analyzing a series of mixing models that utilize various combinations of parameters (i.e. endmember characteristics such as δ13COC, C/N ratios or lignin content). Next, we assess the importance of using more than the minimum number of parameters required to estimate endmember contributions to the total organic matter pool. Then, we quantify the impact of data uncertainty on the outcome of the analysis using Monte Carlo simulations and accounting for the uncertainty in endmember characteristics. Finally, as biogeochemical processes can alter endmember characteristics over time, we investigate the effect of early diagenesis on chosen parameters, an analysis that entails an assessment of the organic matter age distribution. Thus, estimates of the relative contributions of phytoplankton, C3 and C4 plants to bulk sediment organic matter depend not only on environmental characteristics that impact reactivity, but also on sediment mixing processes.

Source-sink-storage relationships of conifers

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

Luxmoore, R.J.; Oren, R.; Sheriff, D.W.

1995-07-01

Irradiance, air temperature, saturation vapor pressure deficit, and soil temperature vary in association with Earth`s daily rotation, inducing significant hourly changes in the rates of plant physiological processes. These processes include carbon fixation in photosynthesis, sucrose translocation, and carbon utilization in growth, storage, and respiration. The sensitivity of these physiological processes to environmental factors such as temperature, soil water availability, and nutrient supply reveals differences that must be viewed as an interactive whole in order to comprehend whole-plant responses to the environment. Integrative frameworks for relationships between plant physiological processes are needed to provide syntheses of plant growth and development.more » Source-sink-storage relationships, addressed in this chapter, provide one framework for synthesis of whole-plant responses to external environmental variables. To address this issue, some examples of carbon assimilation and utilization responses of five conifer species to environmental factors from a range of field environments are first summarized. Next, the interactions between sources, sinks, and storages of carbon are examined at the leaf and tree scales, and finally, the review evaluates the proposition that processes involved with carbon utilization (sink activity) are more sensitive to the supply of water and nutrients (particularly nitrogen) than are the processes of carbon gain (source activity) and carbon storage. The terms {open_quotes}sink{close_quotes} and {open_quotes}source{close_quotes} refer to carbon utilization and carbon gain, respectively. The relative roles of stored carbon reserves and of current photosynthate in meeting sink demand are addressed. Discussions focus on source-sink-storage relationships within the diurnal, wetting-drying, and annual cycles of conifer growth and development, and some discussion of life cycle aspects is also presented.« less

Methods for forming particles from single source precursors

DOEpatents

Fox, Robert V [Idaho Falls, ID; Rodriguez, Rene G [Pocatello, ID; Pak, Joshua [Pocatello, ID

2011-08-23

Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

Effect of carbon source on nitrogen removal in anaerobic ammonium oxidation (anammox) process.

PubMed

Zhu, Weiqiang; Zhang, Peiyu; Dong, Huiyu; Li, Jin

2017-04-01

Anaerobic ammonium oxidation (anammox) has been regarded as an efficient process to treat high-strength wastewater without organic carbon source. To investigate nitrogen removal performance of anammox in presence of organic carbon source can broaden its application on organic wastewater treatment. In this work, effect of carbon source on anammox process was explored. Operating temperature was set at 35 ± 1°C. Influent pH and hydraulic retention time were 7.5 and 6 h, respectively. Effluent [Formula: see text] was affected little with COD no more than 480 mg/L. Independent of carbon source content, nitrite removal rate was around 99%. The variation of [Formula: see text] lagged behind [Formula: see text] at high COD content, and pH could be used as an indicator for [Formula: see text] removal. Specific anammox activity dropped from 0.39 to 0.19  [Formula: see text] at COD=720 mg/L. The remodified logistic model was quite appropriate for describing the nitrogen removal kinetics and predicting the performance of anammox process in presence of carbon source. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

[Quantitative estimation source of urban atmospheric CO2 by carbon isotope composition].

PubMed

Liu, Wei; Wei, Nan-Nan; Wang, Guang-Hua; Yao, Jian; Zeng, You-Shi; Fan, Xue-Bo; Geng, Yan-Hong; Li, Yan

2012-04-01

To effectively reduce urban carbon emissions and verify the effectiveness of currently project for urban carbon emission reduction, quantitative estimation sources of urban atmospheric CO2 correctly is necessary. Since little fractionation of carbon isotope exists in the transportation from pollution sources to the receptor, the carbon isotope composition can be used for source apportionment. In the present study, a method was established to quantitatively estimate the source of urban atmospheric CO2 by the carbon isotope composition. Both diurnal and height variations of concentrations of CO2 derived from biomass, vehicle exhaust and coal burning were further determined for atmospheric CO2 in Jiading district of Shanghai. Biomass-derived CO2 accounts for the largest portion of atmospheric CO2. The concentrations of CO2 derived from the coal burning are larger in the night-time (00:00, 04:00 and 20:00) than in the daytime (08:00, 12:00 and 16:00), and increase with the increase of height. Those derived from the vehicle exhaust decrease with the height increase. The diurnal and height variations of sources reflect the emission and transport characteristics of atmospheric CO2 in Jiading district of Shanghai.

Sources and yields of dissolved carbon in northern Wisconsin stream catchments with differing amounts of Peatland

USGS Publications Warehouse

Elder, J.F.; Rybicki, N.B.; Carter, V.; Weintraub, V.

2000-01-01

In five tributary streams (four inflowing and one outflowing) of 1600-ha Trout Lake in northern Wisconsin, USA, we examined factors that can affect the magnitude of stream flow and transport of dissolved organic and inorganic carbon (DOC and DIC) through the streams to the lake. One catchment, the Allequash Creek basin, was investigated in more detail to describe the dynamics of carbon flow and to identify potential carbon sources. Stream flows and carbon loads showed little or no relation to surface-water catchment area. They were more closely related to ground-water watershed area because ground-water discharge, from both local and regional sources, is a major contributor to the hydrologic budgets of these catchments. An important factor in determining carbon influx to the stream is the area of peatland in the catchment. Peatland porewaters contain DOC concentrations up to 40 mg l-1 and are a significant potential carbon source. Ground-water discharge and lateral flow through peat are the suspected mechanisms for transport of that carbon to the streams. Carbon and nitrogen isotopes suggested that the sources of DOC in Allequash Creek above Allequash Lake were wetland vegetation and peat and that the sources below Allequash Lake were filamentous algae and wild rice. Catchments with high proportions of peatland, including the Allequash Creek catchment, tended to have elevated DOC loads in outflowing stream water. Respiration and carbon mineralization in lakes within the system tend to produce low DOC and low DOC/DIC in lake outflows, especially at Trout Lake. In Allequash Lake, however, the shallow peat island and vegetation-filled west end were sources of DOC. Despite the vast carbon reservoir in the peatlands, carbon yields were very low in these catchments. Maximum yields were on the order of 2.5 g m-2 y-1 DOC and 5.5 g m-2 y-1 DIC. The small yields were attributable to low stream flows due to lack of significant overland runoff and very limited stream channel coverage of the total catchment area.

Mineral Carbonation Potential of CO2 from Natural and Industrial-based Alkalinity Sources

NASA Astrophysics Data System (ADS)

Wilcox, J.; Kirchofer, A.

2014-12-01

Mineral carbonation is a Carbon Capture and Storage (CSS) technology where gaseous CO2 is reacted with alkaline materials (such as silicate minerals and alkaline industrial wastes) and converted into stable and environmentally benign carbonate minerals (Metz et al., 2005). Here, we present a holistic, transparent life cycle assessment model of aqueous mineral carbonation built using a hybrid process model and economic input-output life cycle assessment approach. We compared the energy efficiency and the net CO2 storage potential of various mineral carbonation processes based on different feedstock material and process schemes on a consistent basis by determining the energy and material balance of each implementation (Kirchofer et al., 2011). In particular, we evaluated the net CO2 storage potential of aqueous mineral carbonation for serpentine, olivine, cement kiln dust, fly ash, and steel slag across a range of reaction conditions and process parameters. A preliminary systematic investigation of the tradeoffs inherent in mineral carbonation processes was conducted and guidelines for the optimization of the life-cycle energy efficiency are provided. The life-cycle assessment of aqueous mineral carbonation suggests that a variety of alkalinity sources and process configurations are capable of net CO2 reductions. The maximum carbonation efficiency, defined as mass percent of CO2 mitigated per CO2 input, was 83% for CKD at ambient temperature and pressure conditions. In order of decreasing efficiency, the maximum carbonation efficiencies for the other alkalinity sources investigated were: olivine, 66%; SS, 64%; FA, 36%; and serpentine, 13%. For natural alkalinity sources, availability is estimated based on U.S. production rates of a) lime (18 Mt/yr) or b) sand and gravel (760 Mt/yr) (USGS, 2011). The low estimate assumes the maximum sequestration efficiency of the alkalinity source obtained in the current work and the high estimate assumes a sequestration efficiency of 85%. The total CO2 storage potential for the alkalinity sources considered in the U.S. ranges from 1.3% to 23.7% of U.S. CO2 emissions, depending on the assumed availability of natural alkalinity sources and efficiency of the mineral carbonation processes.

Origin and sources of dissolved organic matter in snow on the East Antarctic ice sheet.

PubMed

Antony, Runa; Grannas, Amanda M; Willoughby, Amanda S; Sleighter, Rachel L; Thamban, Meloth; Hatcher, Patrick G

2014-06-03

Polar ice sheets hold a significant pool of the world's carbon reserve and are an integral component of the global carbon cycle. Yet, organic carbon composition and cycling in these systems is least understood. Here, we use ultrahigh resolution mass spectrometry to elucidate, at an unprecedented level, molecular details of dissolved organic matter (DOM) in Antarctic snow. Tens of thousands of distinct molecular species are identified, providing clues to the nature and sources of organic carbon in Antarctica. We show that many of the identified supraglacial organic matter formulas are consistent with material from microbial sources, and terrestrial inputs of vascular plant-derived materials are likely more important sources of organic carbon to Antarctica than previously thought. Black carbon-like material apparently originating from biomass burning in South America is also present, while a smaller fraction originated from soil humics and appears to be photochemically or microbially modified. In addition to remote continental sources, we document signals of oceanic emissions of primary aerosols and secondary organic aerosol precursors. The new insights on the diversity of organic species in Antarctic snowpack reinforce the importance of studying organic carbon associated with the Earth's polar regions in the face of changing climate.

The Aspergillus nidulans Pyruvate Dehydrogenase Kinases Are Essential To Integrate Carbon Source Metabolism.

PubMed

Ries, Laure Nicolas Annick; de Assis, Leandro José; Rodrigues, Fernando José Santos; Caldana, Camila; Rocha, Marina Campos; Malavazi, Iran; Bayram, Özgür; Goldman, Gustavo H

2018-05-24

The pyruvate dehydrogenase complex (PDH), that converts pyruvate to acetyl-coA, is regulated by pyruvate dehydrogenase kinases (PDHK) and phosphatases (PDHP) that have been shown to be important for morphology, pathogenicity and carbon source utilisation in different fungal species. The aim of this study was to investigate the role played by the three PDHKs PkpA, PkpB and PkpC in carbon source utilisation in the reference filamentous fungus Aspergillus nidulans , in order to unravel regulatory mechanisms which could prove useful for fungal biotechnological and biomedical applications. PkpA and PkpB were shown to be mitochondrial whereas PkpC localised to the mitochondria in a carbon source-dependent manner. Only PkpA was shown to regulate PDH activity. In the presence of glucose, deletion of pkpA and pkpC resulted in reduced glucose utilisation, which affected carbon catabolite repression (CCR) and hydrolytic enzyme secretion, due to de-regulated glycolysis and TCA cycle enzyme activities. Furthermore, PkpC was shown to be required for the correct metabolic utilisation of cellulose and acetate. PkpC negatively regulated the activity of the glyoxylate cycle enzyme isocitrate lyase (ICL), required for acetate metabolism. In summary, this study identified PDHKs important for the regulation of central carbon metabolism in the presence of different carbon sources, with effects on the secretion of biotechnologically important enzymes and carbon source-related growth. This work demonstrates how central carbon metabolism can affect a variety of fungal traits and lays a basis for further investigation into these characteristics with potential interest for different applications. Copyright © 2018, G3: Genes, Genomes, Genetics.

Interannual variability in seagrass carbon and nitrogen stable isotopes from the Florida Keys National Marine Sanctuary, a preliminary study

NASA Astrophysics Data System (ADS)

Fourqurean, J. W.; Fourqurean, J. W.; Anderson, W. T.; Anderson, W. T.

2001-12-01

The shallow marine waters surrounding the southern tip of Florida provide an ideal environment for seagrasses, which are the most common benthic community in the region. Yet, these communities are susceptible to a variety of anthropogenic disturbances, especially changes in water quality caused by an increase the nutrient flux to the near shore environment. In order to better understand the carbon and nitrogen isotopic ratio in marine plants, an extensive times series analysis was constructed from quarterly sampling of Thalassia testudinum (the dominate species in the study area) from 1996 through 1998. Sites for study where selected from permanent stations within the Florida Keys National Marine Sanctuary (FKNMS), from both sides of the Florida Keys - two stations on the bay side and two stations on the reef side. These data will also help to constrain elements of the carbon and nitrogen cycles affecting this region. The data analyzed over the three year study period show unique cyclic trends associated with seasonal changes in primary productivity and potentially changes in the nitrogen and carbon pools. Additionally, the analysis of our time series indicates that isotope food web studies need to take into account spatial and temporal changes when evaluating trophic levels. The mean carbon and nitrogen isotope values of T. testudinum from all 4 stations vary respectively from -7.2 per mil to -10.41 and 1.1 per mil to 2.2 per mil (n = 48). However, certain stations displayed anonymously depleted nitrogen isotope values, values as low as -1.2 per mil. These values potentially indicated that biogeochmical processes like N fixation, ammonification and denitrification cause regional pattern in the isotopic composition of the source DIN. Both carbon and nitrogen isotopes displayed seasonal enrichment-depletion trends, with maximum enrichment occurring during the summer. The overall seasonal variation for carbon 13 from the different stations ranged from 1 per mil to greater than 3 per mil; whereas seasonal variations in d15N between different stations ranged from about 1 per mil to greater than 5 per mil. Additionally certain sites showed a positive isotope values and productivity. These data indicate a high degree of seasonal variability due to changes in productivity, environmental parameters, and oceanographic controls. The more open settings are not restricted by the temperature changes occurring in the shallower water sites. Additionally, carbon and nitrogen sources can change due to the mineralization of OM from different sources from nearby mangrove islands and/or the Everglades to the north.

Airborne microbial allergens: Impact and risk assessment

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

Solomon, W.R.

1990-01-01

Despite their evolution in more natural niches, a variety of microorganisms have also successfully colonized man-made interiors. Such adaptable agents require fairly simple carbon and nitrogen sources, in limited amounts, and find these on surfaces and in fluid collections. Available moisture is also a critical permissive factor. Survival and growth indoors are fostered by the presence of stored biogenic materials and by soiling of surfaces with organic films derived from foodstuffs, soaps, volatile hydrocarbons and organic dusts. Commonly, predators such as protozoa, mites, insects and nematodes graze on a variety of established early invaders so that complex mixed populations aremore » common. At the least, bacteria, fungi and their extracellular products regularly coexist on even marginal substrates.« less

Catabolism and biotechnological applications of cholesterol degrading bacteria

PubMed Central

García, J. L.; Uhía, I.; Galán, B.

2012-01-01

Summary Cholesterol is a steroid commonly found in nature with a great relevance in biology, medicine and chemistry, playing an essential role as a structural component of animal cell membranes. The ubiquity of cholesterol in the environment has made it a reference biomarker for environmental pollution analysis and a common carbon source for different microorganisms, some of them being important pathogens such as Mycobacterium tuberculosis. This work revises the accumulated biochemical and genetic knowledge on the bacterial pathways that degrade or transform this molecule, given that the characterization of cholesterol metabolism would contribute not only to understand its role in tuberculosis but also to develop new biotechnological processes that use this and other related molecules as starting or target materials. PMID:22309478

A review of carbon monoxide sources, sinks, and concentrations in the earth's atmosphere

NASA Technical Reports Server (NTRS)

Bortner, M. H.; Kummler, R. H.; Jaffe, L. S.

1972-01-01

Carbon monoxide is a toxic pollutant which is continually introduced into the earth's atmosphere in significant quantities. There are apparently some mechanisms operating which destroy most of the CO in the atmosphere, i.e., a carbon monoxide sink. These mechanisms have not as yet been established in a quantitative sense. This report discusses the various possible removal mechanisms which warrant serious consideration. Particular emphasis is given to chemical reactions (especially that with OH), soil bacteria and other biological action, and transport effects. The sources of carbon monoxide, both natural and anthropogenic, are reviewed and it is noted that there is quite possibly a significant undefined natural source. Atmospheric CO concentrations are discussed and their implications on carbon monoxide lifetime, sinks and sources are considered.

Chemical and carbon isotopic composition of dissolved organic carbon in a regional confined methanogenic aquifer

USGS Publications Warehouse

Aravena, R.; Wassenaar, L.I.; Spiker, E. C.

2004-01-01

This study demonstrates the advantage of a combined use of chemical and isotopic tools to understand the dissolved organic carbon (DOC) cycle in a regional confined methanogenic aquifer. DOC concentration and carbon isotopic data demonstrate that the soil zone is a primary carbon source of groundwater DOC in areas close to recharge zones. An in-situ DOC source linked to organic rich sediments present in the aquifer matrix is controlling the DOC pool in the central part of the groundwater flow system. DOC fractions, 13C-NMR on fulvic acids and 14C data on DOC and CH4 support the hypothesis that the in-situ DOC source is a terrestrial organic matter and discard the Ordovician bedrock as a source of DOC. ?? 2004 Taylor and Francis Ltd.

Negative Emissions: Where Will the Carbon Come From?

NASA Astrophysics Data System (ADS)

Aines, R. D.; McCoy, S. T.

2017-12-01

The need for energy technologies that remove carbon dioxide from the air grows with each year of delay in acting to address climate change. The most commonly mentioned approach for achieving that, bioenergy with carbon capture and storage (BECCS), today is largely a modeler's concept, not a technology. Thus, in the near term how can we confidently discuss the scale of biomass for energy with a net reduction in CO2 concentrations in the absence of examples? As a first step toward achieving that research objective, this talk frames the likely ways in which net reductions in CO2 concentrations can be achieved from a lifecycle perspective, and the pathways through which biomass can be converted to fuels and materials while removing CO2 from the atmosphere. We will address questions such as: What pathways exist for converting biomass into transportation fuels, electricity, and materials? How can we capture and manage the carbon dioxide emissions from these kinds of activities? And, what are the tradeoffs between pathways? We have conducted preliminary analyses of some of the common biofuel production pathways, such as ethanol from corn with and without carbon capture. These pathways are still uniformly carbon positive, that is to say, they do not achieve the goal of reducing atmospheric CO2, even if they result in lower emissions than do petroleum-based fuels. More advanced pathways appear to have the capacity for minor atmospheric reductions, including those for drop-in replacement transportation fuels and some long-lived materials. Targets and options for improving these technologies to the point that they can, in fact, be carbon negative will be discussed, including pre-processing of the biomass near the production site to reduce transportation emissions, finding ways to manage small CO2 sources associated with processing, and uses of biochar. We will end with a summary of near-term RD&D needs to advance carbon-negative pathways and the associated technologies. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Trade-offs and synergies between carbon storage and livelihood benefits from forest commons.

PubMed

Chhatre, Ashwini; Agrawal, Arun

2009-10-20

Forests provide multiple benefits at local to global scales. These include the global public good of carbon sequestration and local and national level contributions to livelihoods for more than half a billion users. Forest commons are a particularly important class of forests generating these multiple benefits. Institutional arrangements to govern forest commons are believed to substantially influence carbon storage and livelihood contributions, especially when they incorporate local knowledge and decentralized decision making. However, hypothesized relationships between institutional factors and multiple benefits have never been tested on data from multiple countries. By using original data on 80 forest commons in 10 countries across Asia, Africa, and Latin America, we show that larger forest size and greater rule-making autonomy at the local level are associated with high carbon storage and livelihood benefits; differences in ownership of forest commons are associated with trade-offs between livelihood benefits and carbon storage. We argue that local communities restrict their consumption of forest products when they own forest commons, thereby increasing carbon storage. In showing rule-making autonomy and ownership as distinct and important institutional influences on forest outcomes, our results are directly relevant to international climate change mitigation initiatives such as Reduced Emissions from Deforestation and Forest Degradation (REDD) and avoided deforestation. Transfer of ownership over larger forest commons patches to local communities, coupled with payments for improved carbon storage can contribute to climate change mitigation without adversely affecting local livelihoods.

Controls on Mixing-Dependent Denitrification in Hyporheic Zones

NASA Astrophysics Data System (ADS)

Hester, E. T.; Young, K. I.; Widdowson, M. A.

2013-12-01

Interaction of surface water and groundwater in hyporheic sediments of river systems is known to create unique biogeochemical conditions that can attenuate contaminants flowing downstream. Oxygen, carbon, and the contaminants themselves (e.g., excess nitrate) often advect together through the hyporheic zone from sources in surface water. However, the ability of the hyporheic zone to attenuate contaminants in upwelling groundwater plumes as they exit to rivers is less known. Such reactions may be more dependent on mixing of carbon and oxygen sources from surface water with contaminants from deeper groundwater. We simulated hyporheic flow cells and upwelling groundwater together with mixing-dependent denitrification of an upwelling nitrate plume in shallow riverbed sediments using MODFLOW and SEAM3D. For our first set of model scenarios, we set biogeochemical boundary conditions to be consistent with situations where only mixing-dependent denitrification occurred within the model domain. This occurred where dissolved organic carbon (DOC) advecting from surface water through hyporheic flow cells meets nitrate upwelling from deeper groundwater. This would be common where groundwater is affected by septic systems which contribute nitrate that upwells into streams that do not have significant nitrate sources from upstream. We conducted a sensitivity analysis that showed that mixing-dependent denitrification increased with parameters that increase mixing itself, such as the degree of heterogeneity of sediment hydraulic conductivity (K). Mixing-dependent denitrification also increased with certain biogeochemical boundary concentrations such as increasing DOC or decreasing dissolved oxygen (DO) advecting from surface water. For our second set of model scenarios, we set biogeochemical boundary conditions to be consistent with common situations where non-mixing-dependent denitrification also occurred within the model domain. For example, when nitrate concentrations are substantial in water advecting from surface water, non-mixing-dependent denitrification can occur within the hyporheic flow cells. This would be common where surface water and groundwater have high nitrate concentrations in agricultural areas. We conducted a sensitivity analysis for this set of model scenarios as well, to evaluate controls on the relative balance of mixing-dependent and non-mixing-dependent denitrification. We found that non-mixing-dependent denitrification often has higher potential to consume nitrate than mixing-dependent denitrification. This is because non-mixing-dependent denitrification is not confined to the relatively small mixing zone between upwelling groundwater and hyporheic flow cells, and hence often has longer residence times available for consumption of existing oxygen followed by consumption of nitrate. Nevertheless, the potential for hyporheic zones to attenuate upwelling nitrate plumes appears to be substantial, yet is variable depending on geomorphic, hydraulic, and biogeochemical conditions.

[Effects of carbon sources changes on the property and morphology of 2,4-D degraded aerobic sludge granules].

PubMed

Ma, Jing-Yun; Quan, Xian-Chun; Xiong, Wei-Cong

2010-11-01

This study investigated the changes of the morphology, structure, and capability of removing the target contamination of the aerobic granules pre-cultured with mixed substrates of glucose and 2,4-dichlorophenoxyacetic acid (2,4-D) in a long-time running sequence batch reactor (SBR), when the carbon source transformed into the sole carbon source of 2,4-D. Results showed that when the substrate turned to the sole carbon source of 2,4-D, the aerobic granules still maintained a strong degradation ability to the target contamination; a 2,4-D removal percentage of 99.2% -100% and an average COD removal rate of 85.6% were achieved at the initial 2,4-D concentration of 361-564 mg/L. Carbon source transformation caused certain damages to the original aerobic granule structure, made some parts of granules disintegrated, and led to granule size decline from 513 microm to 302 microm. However, those granules maintained the main body, re-aggregated and grew after a period of adaptation due to their strong resistance to toxicity. Aerobic granules capable of utilizing 2,4-D as the sole carbon source with a good settling ability (SYI 20-40 mL/g) and a mean diameter of 489 microm were finally obtained in this study. Scanning electron microscope (SEM) observation showed that the diversity of granule microbial species was declined when turned to the sole carbon source.

CarbonSat Constellation

NASA Astrophysics Data System (ADS)

Sun, Wei; Tobehn, Carsten; Ernst, Robert; Bovensmann, Heinrich; Buchwitz, Michael; Burrows, John P.; Notholt, John

1 Carbon dioxide (CO2) and methane (CH4) are the most important manmade greenhouse gases (GHGs) which are driving global climate change. Currently, the CO2 measurements from the ground observing network are still the main sources of information but due to the limited number of measurement stations the coverage is limited. In addition, CO2 monitoring and trading is often based mainly on bottom-up calculations and an independent top down verification is limited due to the lack of global measurement data with local resolution. The first CO2 and CH4 mapping from SCIAMACHY on ENVISAT shows that satellites add important missing global information. Current GHG measurement satellites (GOSAT)are limited either in spatial or temporal resolution and coverage. These systems have to collect data over a year or even longer to produce global regional fluxes products. Conse-quently global, timely, higher spatial resolution and high accuracy measurement are required for: 1. A good understanding of the CO2 and CH4 sources and sinks for reliable climate predic-tion; and 2. Independent and transparent verification of accountable sources and sinks in supporting Kyoto and upcoming protocols The CarbonSat constellation idea comes out the trade off of resolution and swath width during CarbonSat mission definition studies. In response to the urgent need to support the Kyoto and upcoming protocols, a feasibility study has been carried out. The proposed solution is a constellation of five CarbonSat satellites in 614km LTAN 13:00, which is able to provide global, daily CO2 and CH4 measurement everywhere on the Earth with high spatial resolution 2 × 2 km and low uncertainty lt;2ppm (CO2) and lt;8ppb (CH4). The unique global daily measurement capability significantly increases the number of cloud free measurements, which enables more reliable services associated with reduced uncertainty, e.g. to 0.15ppm (CO2) per month in 10km and even more timely products. The CarbonSat Constellation in combination with inverse modelling techniques will be able to provide information services, such as global quarterly 1. CO2 and CH4 regional flux updates 2. CO2 emission reporting from hot spots e.g. the power plant 3. CH4 emission reporting from hot spots e.g. the pipeline/oil and gas fields. The team led by the industry partner -OHB now promotes an internationally coordinated CarbonSat constellation to provide operational services contributing to the independent iden-tification and verification of man-made & natural CO2 and CH4 emissions and claimed carbon sinks. It is proposed that the CarbonSat Constellation will be implemented through an internation-ally coordinated constellation. Each country contributes one satellite in the constellation and establishes its own ground station to provide data for national applications. A central coordi-nation will be set up for the constellation operation, data calibration and international data distribution. The proposed approach provides independence for each partner and is financially more feasible. In addition, the CarbonSat Constellation consortium could be a bridge/forum between developed countries and developing countries in establishing common understandings of and actions on the global climate change. The world wide transparency provided by this international forum is also critical in supporting Kyoto protocol and upcoming international agreement in man-made Greenhouse emission reduction. The paper will present the CarbonSat Constellation design and the proposed products/ services to verify CO2 and CH4 sources and sinks from a constellation of five CarbonSat satellites through a multilateral collaboration.

Production of polyhydroxybutyrate by the marine photosynthetic bacterium Rhodovulum sulfidophilum P5

NASA Astrophysics Data System (ADS)

Cai, Jinling; Wei, Ying; Zhao, Yupeng; Pan, Guanghua; Wang, Guangce

2012-07-01

The effects of different NaCl concentrations, nitrogen sources, carbon sources, and carbon to nitrogen molar ratios on biomass accumulation and polyhydroxybutyrate (PHB) production were studied in batch cultures of the marine photosynthetic bacterium Rhodovulum sulfidophilum P5 under aerobic-dark conditions. The results show that the accumulation of PHB in strain P5 is a growth-associated process. Strain P5 had maximum biomass and PHB accumulation at 2%-3% NaCl, suggesting that the bacterium can maintain growth and potentially produce PHB at natural seawater salinity. In the nitrogen source test, the maximum biomass accumulation (8.10±0.09 g/L) and PHB production (1.11±0.13 g/L and 14.62%±2.2 of the cell dry weight) were observed when peptone and ammonium chloride were used as the sole nitrogen source. NH{4/+}-N was better for PHB production than other nitrogen sources. In the carbon source test, the maximum biomass concentration (7.65±0.05 g/L) was obtained with malic acid as the sole carbon source, whereas the maximum yield of PHB (5.03±0.18 g/L and 66.93%±1.69% of the cell dry weight) was obtained with sodium pyruvate as the sole carbon source. In the carbon to nitrogen ratios test, sodium pyruvate and ammonium chloride were selected as the carbon and nitrogen sources, respectively. The best carbon to nitrogen molar ratio for biomass accumulation (8.77±0.58 g/L) and PHB production (6.07±0.25 g/L and 69.25%±2.05% of the cell dry weight) was 25. The results provide valuable data on the production of PHB by R. sulfidophilum P5 and further studies are on-going for best cell growth and PHB yield.

De novo biosynthesis of sterols and fatty acids in the Trypanosoma brucei procyclic form: Carbon source preferences and metabolic flux redistributions

PubMed Central

Bouyssou, Guillaume; Allmann, Stefan; Kiema, Tiila-Riikka; Biran, Marc; Plazolles, Nicolas; Dittrich-Domergue, Franziska; Crouzols, Aline; Wierenga, Rik K.; Rotureau, Brice; Moreau, Patrick

2018-01-01

De novo biosynthesis of lipids is essential for Trypanosoma brucei, a protist responsible for the sleeping sickness. Here, we demonstrate that the ketogenic carbon sources, threonine, acetate and glucose, are precursors for both fatty acid and sterol synthesis, while leucine only contributes to sterol production in the tsetse fly midgut stage of the parasite. Degradation of these carbon sources into lipids was investigated using a combination of reverse genetics and analysis of radio-labelled precursors incorporation into lipids. For instance, (i) deletion of the gene encoding isovaleryl-CoA dehydrogenase, involved in the leucine degradation pathway, abolished leucine incorporation into sterols, and (ii) RNAi-mediated down-regulation of the SCP2-thiolase gene expression abolished incorporation of the three ketogenic carbon sources into sterols. The SCP2-thiolase is part of a unidirectional two-step bridge between the fatty acid precursor, acetyl-CoA, and the precursor of the mevalonate pathway leading to sterol biosynthesis, 3-hydroxy-3-methylglutaryl-CoA. Metabolic flux through this bridge is increased either in the isovaleryl-CoA dehydrogenase null mutant or when the degradation of the ketogenic carbon sources is affected. We also observed a preference for fatty acids synthesis from ketogenic carbon sources, since blocking acetyl-CoA production from both glucose and threonine abolished acetate incorporation into sterols, while incorporation of acetate into fatty acids was increased. Interestingly, the growth of the isovaleryl-CoA dehydrogenase null mutant, but not that of the parental cells, is interrupted in the absence of ketogenic carbon sources, including lipids, which demonstrates the essential role of the mevalonate pathway. We concluded that procyclic trypanosomes have a strong preference for fatty acid versus sterol biosynthesis from ketogenic carbon sources, and as a consequence, that leucine is likely to be the main source, if not the only one, used by trypanosomes in the infected insect vector digestive tract to feed the mevalonate pathway. PMID:29813135

Enhanced lipid production by Rhodosporidium toruloides using different fed-batch feeding strategies with lignocellulosic hydrolysate as the sole carbon source

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

Fei, Qiang; O'Brien, Marykate; Nelson, Robert

Industrial biotechnology that is able to provide environmentally friendly bio-based products has attracted more attention in replacing petroleum-based industries. Currently, most of the carbon sources used for fermentation-based bioprocesses are obtained from agricultural commodities that are used as foodstuff for human beings. Lignocellulose-derived sugars as the non-food, green, and sustainable alternative carbon sources have great potential to avoid this dilemma for producing the renewable, bio-based hydrocarbon fuel precursors, such as microbial lipid. Efficient bioconversion of lignocellulose-based sugars into lipids is one of the critical parameters for industrial application. Therefore, the fed-batch cultivation, which is a common method used in industrialmore » applications, was investigated to achieve a high cell density culture along with high lipid yield and productivity. In this study, several fed-batch strategies were explored to improve lipid production using lignocellulosic hydrolysates derived from corn stover. Compared to the batch culture giving a lipid yield of 0.19 g/g, the dissolved-oxygen-stat feeding mode increased the lipid yield to 0.23 g/g and the lipid productivity to 0.33 g/L/h. The pulse feeding mode further improved lipid productivity to 0.35 g/L/h and the yield to 0.24 g/g. However, the highest lipid yield (0.29 g/g) and productivity (0.4 g/L/h) were achieved using an automated online sugar control feeding mode, which gave a dry cell weight of 54 g/L and lipid content of 59 % (w/w). The major fatty acids of the lipid derived from lignocellulosic hydrolysates were predominately palmitic acid and oleic acid, which are similar to those of conventional oilseed plants. Our results suggest that the fed-batch feeding strategy can strongly influence the lipid production. Lastly, the online sugar control feeding mode was the most appealing strategy for high cell density, lipid yield, and lipid productivity using lignocellulosic hydrolysates as the sole carbon source.« less

Enhanced lipid production by Rhodosporidium toruloides using different fed-batch feeding strategies with lignocellulosic hydrolysate as the sole carbon source

DOE PAGES

Fei, Qiang; O'Brien, Marykate; Nelson, Robert; ...

2016-06-23

Industrial biotechnology that is able to provide environmentally friendly bio-based products has attracted more attention in replacing petroleum-based industries. Currently, most of the carbon sources used for fermentation-based bioprocesses are obtained from agricultural commodities that are used as foodstuff for human beings. Lignocellulose-derived sugars as the non-food, green, and sustainable alternative carbon sources have great potential to avoid this dilemma for producing the renewable, bio-based hydrocarbon fuel precursors, such as microbial lipid. Efficient bioconversion of lignocellulose-based sugars into lipids is one of the critical parameters for industrial application. Therefore, the fed-batch cultivation, which is a common method used in industrialmore » applications, was investigated to achieve a high cell density culture along with high lipid yield and productivity. In this study, several fed-batch strategies were explored to improve lipid production using lignocellulosic hydrolysates derived from corn stover. Compared to the batch culture giving a lipid yield of 0.19 g/g, the dissolved-oxygen-stat feeding mode increased the lipid yield to 0.23 g/g and the lipid productivity to 0.33 g/L/h. The pulse feeding mode further improved lipid productivity to 0.35 g/L/h and the yield to 0.24 g/g. However, the highest lipid yield (0.29 g/g) and productivity (0.4 g/L/h) were achieved using an automated online sugar control feeding mode, which gave a dry cell weight of 54 g/L and lipid content of 59 % (w/w). The major fatty acids of the lipid derived from lignocellulosic hydrolysates were predominately palmitic acid and oleic acid, which are similar to those of conventional oilseed plants. Our results suggest that the fed-batch feeding strategy can strongly influence the lipid production. Lastly, the online sugar control feeding mode was the most appealing strategy for high cell density, lipid yield, and lipid productivity using lignocellulosic hydrolysates as the sole carbon source.« less

Carbon Concentration and Carbon-to-Nitrogen Ratio Influence Submerged-Culture Conidiation by the Potential Bioherbicide Colletotrichum truncatum NRRL 13737

PubMed Central

Jackson, Mark A.; Bothast, Rodney J.

1990-01-01

We assessed the influence of various carbon concentrations and carbon-to-nitrogen (C:N) ratios on Colletotrichum truncatum NRRL 13737 conidium formation in submerged cultures grown in a basal salts medium containing various amounts of glucose and Casamino Acids. Under the nutritional conditions tested, the highest conidium concentrations were produced in media with carbon concentrations of 4.0 to 15.3 g/liter. High carbon concentrations (20.4 to 40.8 g/liter) inhibited sporulation and enhanced the formation of microsclerotiumlike hyphal masses. At all the carbon concentrations tested, a culture grown in a medium with a C:N ratio of 15:1 produced more conidia than cultures grown in media with C:N ratios of 40:1 or 5:1. While glucose exhaustion was often coincident with conidium formation, cultures containing residual glucose sporulated and those with high carbon concentrations (>25 g/liter) exhausted glucose without sporulation. Nitrogen source studies showed that the levels of C. truncatum NRRL 13737 conidiation were similar for all protein hydrolysates tested. Reduced conidiation occurred when amino acid and inorganic nitrogen sources were used. Of the nine carbon sources evaluated, acetate as the sole carbon source resulted in the lowest level of sporulation. Images PMID:16348348

The influence of different nitrogen and carbon sources on mycotoxin production in Alternaria alternata.

PubMed

Brzonkalik, Katrin; Herrling, Tanja; Syldatk, Christoph; Neumann, Anke

2011-05-27

The aim of this study was to determine the influence of different carbon and nitrogen sources on the production of the mycotoxins alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by Alternaria alternata at 28°C using a semi-synthetic medium (modified Czapek-Dox broth) supplemented with nitrogen and carbon sources. Additionally the effect of shaken and static cultivation on mycotoxin production was tested. Initial experiments showed a clear dependency between nitrogen depletion and mycotoxin production. To assess whether nitrogen limitation in general or the type of nitrogen source triggers the production, various nitrogen sources including several ammonium/nitrate salts and amino acids were tested. In static culture the production of AOH/AME can be enhanced greatly with phenylalanine whereas some nitrogen sources seem to inhibit the AOH/AME production completely. TA was not significantly affected by the choice of nitrogen source. In shaken culture the overall production of all mycotoxins was lower compared to static cultivation. Furthermore tests with a wide variety of carbon sources including monosaccharides, disaccharides, complex saccharides such as starch as well as glycerol and acetate were performed. In shaken culture AOH was produced when glucose, fructose, sucrose, acetate or mixtures of glucose/sucrose and glucose/acetate were used as carbon sources. AME production was not detected. The use of sodium acetate resulted in the highest AOH production. In static culture AOH production was also stimulated by acetate and the amount is comparable to shaken conditions. Under static conditions production of AOH was lower except when cultivated with acetate. In static cultivation 9 of 14 tested carbon sources induced mycotoxin production compared to 4 in shaken culture. This is the first study which analyses the influence of carbon and nitrogen sources in a semi-synthetic medium and assesses the effects of culture conditions on mycotoxin production by A. alternata. Copyright © 2011 Elsevier B.V. All rights reserved.

Carbon utilization profiles of river bacterial strains facing sole carbon sources suggest metabolic interactions.

PubMed

Goetghebuer, Lise; Servais, Pierre; George, Isabelle F

2017-05-01

Microbial communities play a key role in water self-purification. They are primary drivers of biogenic element cycles and ecosystem processes. However, these communities remain largely uncharacterized. In order to understand the diversity-heterotrophic activity relationship facing sole carbon sources, we assembled a synthetic community composed of 20 'typical' freshwater bacterial species mainly isolated from the Zenne River (Belgium). The carbon source utilization profiles of each individual strain and of the mixed community were measured in Biolog Phenotype MicroArrays PM1 and PM2A microplates that allowed testing 190 different carbon sources. Our results strongly suggest interactions occurring between our planktonic strains as our synthetic community showed metabolic properties that were not displayed by its single components. Finally, the catabolic performances of the synthetic community and a natural community from the same sampling site were compared. The synthetic community behaved like the natural one and was therefore representative of the latter in regard to carbon source consumption. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Placing barrier-island transgression in a blue-carbon context

NASA Astrophysics Data System (ADS)

Theuerkauf, Ethan J.; Rodriguez, Antonio B.

2017-07-01

Backbarrier saltmarshes are considered carbon sinks; however, barrier island transgression and the associated processes of erosion and overwash are typically not included in coastal carbon budgets. Here, we present a carbon-budget model for transgressive barrier islands that includes a dynamic carbon-storage term, driven by backbarrier-marsh width, and a carbon-export term, driven by ocean and backbarrier shoreline erosion. To examine the impacts of storms, human disturbances and the backbarrier setting of a transgressive barrier island on carbon budgets and reservoirs, the model was applied to sites at Core Banks and Onslow Beach, NC, USA. Results show that shoreline erosion and burial of backbarrier marsh from washover deposition and dredge-spoil disposal temporarily transitioned each site into a net exporter (source) of carbon. The magnitude of the carbon reservoir was linked to the backbarrier setting of an island. Carbon reservoirs of study sites separated from the mainland by only backbarrier marsh (no lagoon) decreased for over a decade because carbon storage could not keep pace with erosion. With progressive narrowing of the backbarrier marsh, these barriers will begin to function more persistently as carbon sources until the reservoir is depleted at the point where the barrier welds with the mainland. Undeveloped barrier islands with wide lagoons are carbon sources briefly during erosive periods; however, at century time scales are net carbon importers (sinks) because new marsh habitat can form during barrier rollover. Human development on backbarrier saltmarsh serves to reduce the carbon storage capacity and can hasten the transition of an island from a sink to a source.

Distribution, origin and prediction of carbon dioxide in petroleum reservoirs

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

Thrasher, J.; Fleet, A.J.

1995-08-01

High concentrations of carbon dioxide (CO{sub 2}) in petroleum reservoirs can significantly reduce the value of the discovery, by diluting any hydrocarbons, and by increasing production costs because of the increased likelihood of corrosion and scale formation. Huge volumes of CO{sub 2} have been found, for example in the Indonesian Natuna d-Alpha structure (estimated 240 tcf gas, of which around 70% is CO{sub 2}). This study reviews the possible sources of CO{sub 2} in the petroleum system, and the geological and geochemical data from some CO{sub 2} {open_quotes}polluted{close_quotes} reservoirs, to improve future predictions of the exploration risk of finding significantmore » CO{sub 2}. A number of case studies show that the most common geological circumstances for the occurrence of high concentrations of CO{sub 2} include: carbonates associated with post-trap igneous activity (e.g. Ibleo Platform, Sicily); reservoir close to hot basement (e.g. Cooper-Eromanga Basin, Australia) and deep faults close to traps (e.g. Gulf of Thailand). Less common circumstances for high proportions of CO{sub 2} in gas include: post-trap igneous activity and coals (e.g. Taranaki, New Zealand) and reservoirs associated with pre-oil window coaly kerogen (e.g. Malay Trough), although the volumes of CO{sub 2} generated from kerogen are usually low relative to volumes of hydrocarbons generated from kerogen.« less

Tectonic evolution, structural styles, and oil habitat in Campeche Sound, Mexico

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

Angeles-Aquino, F.J.; Reyes-Nunez, J.; Quezada-Muneton, J.M.

1994-12-31

Campeche Sound is located in the southern part of the Gulf of Mexico. This area is Mexico`s most important petroleum province. The Mesozoic section includes Callovian salt deposits; Upper Jurassic sandstones, anhydrites, limestones, and shales; and Cretaceous limestones, dolomites, shales, and carbonate breccias. The Cenozoic section is formed by bentonitic shales and minor sandstones and carbonate breccias. Campeche Sound has been affected by three episodes of deformation: first extensional tectonism, then compressional tectonism, and finally extensional tectonism again. The first period of deformation extended from the middle Jurassic to late Jurassic and is related to the opening of the Gulfmore » of Mexico. During this regime, tilted block faults trending northwest-southwest were dominant. The subsequent compressional regime occurred during the middle Miocene, and it was related to northeast tangential stresses that induced further flow of Callovian salt and gave rise to large faulted, and commonly overturned, anticlines. The last extensional regime lasted throughout the middle and late Miocene, and it is related to salt tectonics and growth faults that have a middle Miocene shaly horizon as the main detachment surface. The main source rocks are Tithonian shales and shaly limestones. Oolite bars, slope and shelf carbonates, and regressive sandstones form the main reservoirs. Evaporites and shales are the regional seals. Recent information indicates that Oxfordian shaly limestones are also important source rocks.« less

The origin, source, and cycling of methane in deep crystalline rock biosphere.

PubMed

Kietäväinen, Riikka; Purkamo, Lotta

2015-01-01

The emerging interest in using stable bedrock formations for industrial purposes, e.g., nuclear waste disposal, has increased the need for understanding microbiological and geochemical processes in deep crystalline rock environments, including the carbon cycle. Considering the origin and evolution of life on Earth, these environments may also serve as windows to the past. Various geological, chemical, and biological processes can influence the deep carbon cycle. Conditions of CH4 formation, available substrates and time scales can be drastically different from surface environments. This paper reviews the origin, source, and cycling of methane in deep terrestrial crystalline bedrock with an emphasis on microbiology. In addition to potential formation pathways of CH4, microbial consumption of CH4 is also discussed. Recent studies on the origin of CH4 in continental bedrock environments have shown that the traditional separation of biotic and abiotic CH4 by the isotopic composition can be misleading in substrate-limited environments, such as the deep crystalline bedrock. Despite of similarities between Precambrian continental sites in Fennoscandia, South Africa and North America, where deep methane cycling has been studied, common physicochemical properties which could explain the variation in the amount of CH4 and presence or absence of CH4 cycling microbes were not found. However, based on their preferred carbon metabolism, methanogenic microbes appeared to have similar spatial distribution among the different sites.

The origin, source, and cycling of methane in deep crystalline rock biosphere

PubMed Central

Kietäväinen, Riikka; Purkamo, Lotta

2015-01-01

The emerging interest in using stable bedrock formations for industrial purposes, e.g., nuclear waste disposal, has increased the need for understanding microbiological and geochemical processes in deep crystalline rock environments, including the carbon cycle. Considering the origin and evolution of life on Earth, these environments may also serve as windows to the past. Various geological, chemical, and biological processes can influence the deep carbon cycle. Conditions of CH4 formation, available substrates and time scales can be drastically different from surface environments. This paper reviews the origin, source, and cycling of methane in deep terrestrial crystalline bedrock with an emphasis on microbiology. In addition to potential formation pathways of CH4, microbial consumption of CH4 is also discussed. Recent studies on the origin of CH4 in continental bedrock environments have shown that the traditional separation of biotic and abiotic CH4 by the isotopic composition can be misleading in substrate-limited environments, such as the deep crystalline bedrock. Despite of similarities between Precambrian continental sites in Fennoscandia, South Africa and North America, where deep methane cycling has been studied, common physicochemical properties which could explain the variation in the amount of CH4 and presence or absence of CH4 cycling microbes were not found. However, based on their preferred carbon metabolism, methanogenic microbes appeared to have similar spatial distribution among the different sites. PMID:26236303

Deadwood biomass: an underestimated carbon stock in degraded tropical forests?

NASA Astrophysics Data System (ADS)

Pfeifer, Marion; Lefebvre, Veronique; Turner, Edgar; Cusack, Jeremy; Khoo, MinSheng; Chey, Vun K.; Peni, Maria; Ewers, Robert M.

2015-04-01

Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are unaffected by logging, despite the fact that coarse woody debris (deadwood with ≥10 cm diameter) can contain significant portions of a forest’s carbon stock. We used a field-based assessment to quantify how the relative contribution of deadwood to total above-ground carbon stock changes across a disturbance gradient, from unlogged old-growth forest to severely degraded twice-logged forest, to oil palm plantation. We measured in 193 vegetation plots (25 × 25 m), equating to a survey area of >12 ha of tropical humid forest located within the Stability of Altered Forest Ecosystems Project area, in Sabah, Malaysia. Our results indicate that significant amounts of carbon are stored in deadwood across forest stands. Live tree carbon storage decreased exponentially with increasing forest degradation 7-10 years after logging while deadwood accounted for >50% of above-ground carbon stocks in salvage-logged forest stands, more than twice the proportion commonly assumed in the literature. This carbon will be released as decomposition proceeds. Given the high rates of deforestation and degradation presently occurring in Southeast Asia, our findings have important implications for the calculation of current carbon stocks and sources as a result of human-modification of tropical forests. Assuming similar patterns are prevalent throughout the tropics, our data may indicate a significant global challenge to calculating global carbon fluxes, as selectively-logged forests now represent more than one third of all standing tropical humid forests worldwide.

Manganese carbonates in the Upper Jurassic Georgiev Formation of the Western Siberian marine basin

NASA Astrophysics Data System (ADS)

Eder, Vika G.; Föllmi, Karl B.; Zanin, Yuri N.; Zamirailova, Albina G.

2018-01-01

Manganese (Mn) carbonate rocks are a common lithological constituent of the Upper Oxfordian to Lower Tithonian (Volgian) Georgiev Formation of the Western Siberian marine basin (WSMB). The Mn carbonates in the Georgiev Formation are present in the form of massive sediments, stromatolites, and oncolites, and are associated with glauconite and partly also phosphate-rich clay- and siltstones. Unlike most Mn carbonates, they are not directly associated with organic-rich sediments, but occur below an organic-rich succession (Bazhenov Formation). The Mn carbonate occurrences can be traced from the western central area of the WSMB to its center along a distance of at least 750 km. The thickness of the Mn carbonates and their Mn contents becomes reduced in an eastward direction, related to increased detrital input. The geochemical and mineralogical heterogeneity within the Mn carbonates indicates that they were deposited stepwise in a diagenetic regime characterized by steep gradients in Mn, Ca, and Mg. A first step consisted in the replacement of initial sediments within the microbialites during an early diagenetic stage, followed by a second step where massive sediments were transformed into Mn carbonate. During both steps, the decomposition of organic matter was an important source of the newly formed carbonate. During a further step, voids were cemented by Mn carbonates, which are rich in pyrite. This last generation may only have formed once the organic-rich sediments of the overlying Bazhenov Formation were deposited. Accumulation of the Mn carbonates in the Upper Jurassic WSMB was controlled by the proximity of Mn-enriched parent rocks, likely in the Ural, which were subjected to intense geochemical weathering during the Late Jurassic.

The role of historical fire disturbance in the carbon dynamics of the pan-boreal region: A process-based analysis

USGS Publications Warehouse

Balshi, M. S.; McGuire, A.D.; Zhuang, Q.; Melillo, J.; Kicklighter, D.W.; Kasischke, E.; Wirth, C.; Flannigan, M.; Harden, J.; Clein, Joy S.; Burnside, T.J.; McAllister, J.; Kurz, W.A.; Apps, M.; Shvidenko, A.

2007-01-01

Wildfire is a common occurrence in ecosystems of northern high latitudes, and changes in the fire regime of this region have consequences for carbon feedbacks to the climate system. To improve our understanding of how wildfire influences carbon dynamics of this region, we used the process-based Terrestrial Ecosystem Model to simulate fire emissions and changes in carbon storage north of 45??N from the start of spatially explicit historically recorded fire records in the twentieth century through 2002, and evaluated the role of fire in the carbon dynamics of the region within the context of ecosystem responses to changes in atmospheric CO2 concentration and climate. Our analysis indicates that fire plays an important role in interannual and decadal scale variation of source/sink relationships of northern terrestrial ecosystems and also suggests that atmospheric CO2 may be important to consider in addition to changes in climate and fire disturbance. There are substantial uncertainties in the effects of fire on carbon storage in our simulations. These uncertainties are associated with sparse fire data for northern Eurasia, uncertainty in estimating carbon consumption, and difficulty in verifying assumptions about the representation of fires that occurred prior to the start of the historical fire record. To improve the ability to better predict how fire will influence carbon storage of this region in the future, new analyses of the retrospective role of fire in the carbon dynamics of northern high latitudes should address these uncertainties. Copyright 2007 by the American Geophysical Union.

Lignin-Derived Advanced Carbon Materials

DOE PAGES

Chatterjee, Sabornie; Saito, Tomonori

2015-11-16

Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, it has been found that lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein, we discuss the lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure–property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templatedmore » carbon.« less

Lignin-Derived Advanced Carbon Materials

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

Chatterjee, Sabornie; Saito, Tomonori

Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, it has been found that lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein, we discuss the lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure–property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templatedmore » carbon.« less

Spatial variation in below ground carbon cycling in a pristine peatland, driven by present and past vegetation

NASA Astrophysics Data System (ADS)

Mathijssen, Paul; Knorr, Klaus-Holger; Gałka, Mariusz; Borken, Werner

2017-04-01

Peat carbon cycling is controlled by both large scale factors, such as climate and hydrological setting, and small scale factors, such as microtopography, vegetation, litter quality, and rooting depth. These small scale factors commonly vary within peatlands, causing variation in the carbon balance at different locations within the same site. Understanding the relationship between small scale carbon cycling and vegetation helps us to assess the variation of carbon dynamics of peatlands, because vegetation composition acts as an integrator of factors such as microtopography, hydrology, and nutrient level. Variation in vegetation illustrates spatial variation of these underlying factors. Furthermore, the presence of certain plant species affects carbon cycling directly through litter quality or aeration through root tissues. In order to understand these within-site variations in terms of carbon cycling, we investigated carbon accumulation, decomposition, and biogeochemistry of pore waters along a transect of peat cores with changing vegetation and water levels in an ombrotrophic peatland in southern Patagonia. The transect ran from a Sphagnum magellanicum dominated spot with relatively high water table, to intermediately wet spots with mixed Sphagnum/shrubs vegetation, or dominated by Cyperaceae, eventually to a more elevated and drier spot dominated by cushion plants (mainly Astelia pumila). There were large differences in peat accumulation rates and peat densities, with faster peat growth and lower densities under Sphagnum, but overall carbon accumulation rates were quite similar in the various microenvironments. At most plots C/N ratios decreased with depth, concurrent with increasing humification index derived from FT-IR spectra. But under cushion plants this relation was opposite: more humification with depth, but also C/N ratios increases. This reflected the differing source material at depth under the cushion plants, and that the cushion plant peat layers were formed on top of Sphagnum peat. The divergent source material throughout a peat core makes it difficult to use C/N ratios to indicate peat decomposition rates. Although the low peat density and higher C/N ratios indicate that overall carbon turnover is slow at Sphagnum plots, pore water methane concentrations were elevated. At cushion plant plots, however, higher redox potentials exist until greater depths due to aerenchymous roots, inhibiting methane production and release. Our results demonstrate that large variation exists within pristine bogs, in terms of decomposition patterns, organic matter quality, and carbon turnover pathways, corresponding to variation in surface moisture levels and vegetation. Furthermore, variation in carbon cycling properties are maintained in buried peat layers and reflect more the organic material of that layer, than the current surface carbon dynamics.

Developing a data life cycle for carbon and greenhouse gas measurements: challenges, experiences and visions

NASA Astrophysics Data System (ADS)

Kutsch, W. L.

2015-12-01

Environmental research infrastructures and big data integration networks require common data policies, standardized workflows and sophisticated e-infrastructure to optimise the data life cycle. This presentation summarizes the experiences in developing the data life cycle for the Integrated Carbon Observation System (ICOS), a European Research Infrastructure. It will also outline challenges that still exist and visions for future development. As many other environmental research infrastructures ICOS RI built on a large number of distributed observational or experimental sites. Data from these sites are transferred to Thematic Centres and quality checked, processed and integrated there. Dissemination will be managed by the ICOS Carbon Portal. This complex data life cycle has been defined in detail by developing protocols and assigning responsibilities. Since data will be shared under an open access policy there is a strong need for common data citation tracking systems that allow data providers to identify downstream usage of their data so as to prove their importance and show the impact to stakeholders and the public. More challenges arise from interoperating with other infrastructures or providing data for global integration projects as done e.g. in the framework of GEOSS or in global integration approaches such as fluxnet or SOCAt. Here, common metadata systems are the key solutions for data detection and harvesting. The metadata characterises data, services, users and ICT resources (including sensors and detectors). Risks may arise when data of high and low quality are mixed during this process or unexperienced data scientists without detailed knowledge on the data aquisition derive scientific theories through statistical analyses. The vision of fully open data availability is expressed in a recent GEO flagship initiative that will address important issues needed to build a connected and interoperable global network for carbon cycle and greenhouse gas observations and aims to meet the most urgent needs for integration between different information sources and methodologies, between different regional networks and from data providers to users.

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.

Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

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

Mayorga, E; Aufdenkampe, A K; Masiello, C A

2005-06-23

Rivers are generally supersaturated with respect to carbon dioxide, resulting in large gas evasion fluxes that can be a significant component of regional net carbon budgets. Amazonian rivers were recently shown to outgas more than ten times the amount of carbon exported to the ocean in the form of total organic carbon or dissolved inorganic carbon. High carbon dioxide concentrations in rivers originate largely from in situ respiration of organic carbon, but little agreement exists about the sources or turnover times of this carbon. Here we present results of an extensive survey of the carbon isotope composition ({sup 13}C andmore » {sup 14}C) of dissolved inorganic carbon and three size-fractions of organic carbon across the Amazonian river system. We find that respiration of contemporary organic matter (less than 5 years old) originating on land and near rivers is the dominant source of excess carbon dioxide that drives outgassing in mid-size to large rivers, although we find that bulk organic carbon fractions transported by these rivers range from tens to thousands of years in age. We therefore suggest that a small, rapidly cycling pool of organic carbon is responsible for the large carbon fluxes from land to water to atmosphere in the humid tropics.« less

Electrochemical process for the preparation of nitrogen fertilizers

DOEpatents

Aulich, Ted R.; Olson, Edwin S.; Jiang, Junhua

2013-03-19

The present invention provides methods and apparatus for the preparation of nitrogen fertilizers including ammonium nitrate, urea, urea-ammonium nitrate, and/or ammonia utilizing a source of carbon, a source of nitrogen, and/or a source of hydrogen. Implementing an electrolyte serving as ionic charge carrier, (1) ammonium nitrate is produced via the reduction of a nitrogen source at the cathode and the oxidation of a nitrogen source at the anode; (2) urea or its isomers are produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source; (3) ammonia is produced via the reduction of nitrogen source at the cathode and the oxidation of a hydrogen source at the anode; and (4) urea-ammonium nitrate is produced via the simultaneous cathodic reduction of a carbon source and a nitrogen source, and anodic oxidation of a nitrogen source. The electrolyte can be solid.

A review of volatile compounds in tektites, and carbon content and isotopic composition of moldavite glass

NASA Astrophysics Data System (ADS)

Žák, Karel; SkáLA, Roman; Šanda, Zdeněk.; Mizera, Jiří.

2012-06-01

Tektites, natural silica-rich glasses produced during impact events, commonly contain bubbles. The paper reviews published data on pressure and composition of a gas phase contained in the tektite bubbles and data on other volatile compounds which can be released from tektites by either high-temperature melting or by crushing or milling under vacuum. Gas extraction from tektites using high-temperature melting generally produced higher gas yield and different gas composition than the low-temperature extraction using crushing or milling under vacuum. The high-temperature extraction obviously releases volatiles not only from the bubbles, but also volatile compounds contained directly in the glass. Moreover, the gas composition can be modified by reactions between the released gases and the glass melt. Published data indicate that besides CO2 and/or CO in the bubbles, another carbon reservoir is present directly in the tektite glass. To clarify the problem of carbon content and carbon isotopic composition of the tektite glass, three samples from the Central European tektite strewn field—moldavites—were analyzed. The samples contained only 35-41 ppm C with δ13C values in the range from -28.5 to -29.9‰ VPDB. This indicates that terrestrial organic matter was a dominant carbon source during moldavite formation.

Variation in Baiting Intensity Among CO2-Baited Traps Used to Collect Hematophagous Arthropods

PubMed Central

Springer, Yuri P.; Taylor, Jeffrey R.; Travers, Patrick D.

2015-01-01

Hematophagous arthropods transmit the etiological agents of numerous diseases and as a result are frequently the targets of sampling to characterize vector and pathogen populations. Arguably, the most commonly used sampling approach involves traps baited with carbon dioxide. We report results of a laboratory study in which the performance of carbon dioxide-baited traps was evaluated using measures of baiting intensity, the amount of carbon dioxide released per unit time during trap deployment. We evaluated the effects of trap design, carbon dioxide source, and wind speed on baiting intensity and documented significant effects of these factors on the length of sampling (time to baiting intensity = 0), maximum baiting intensity, and variation in baiting intensity during experimental trials. Among the three dry ice-baited trap types evaluated, traps utilizing insulated beverage coolers as dry ice containers sampled for the longest period of time, had the lowest maximum but most consistent baiting intensity within trials and were least sensitive to effects of wind speed and dry ice form (block vs. pellet) on baiting intensity. Results of trials involving traps baited with carbon dioxide released from pressurized cylinders suggested that this trap type had performance comparable to dry ice-baited insulated cooler traps but at considerably higher cost. PMID:26160803

Can reducing black carbon emissions counteract global warming?

PubMed

Bond, Tami C; Sun, Haolin

2005-08-15

Field measurements and model results have recently shown that aerosols may have important climatic impacts. One line of inquiry has investigated whether reducing climate-warming soot or black carbon aerosol emissions can form a viable component of mitigating global warming. We review and acknowledge scientific arguments against considering aerosols and greenhouse gases in a common framework, including the differences in the physical mechanisms of climate change and relevant time scales. We argue that such a joint consideration is consistent with the language of the United Nations Framework Convention on Climate Change. We synthesize results from published climate-modeling studies to obtain a global warming potential for black carbon relative to that of CO2 (680 on a 100 year basis). This calculation enables a discussion of cost-effectiveness for mitigating the largest sources of black carbon. We find that many emission reductions are either expensive or difficult to enact when compared with greenhouse gases, particularly in Annex I countries. Finally, we propose a role for black carbon in climate mitigation strategies that is consistent with the apparently conflicting arguments raised during our discussion. Addressing these emissions is a promising way to reduce climatic interference primarily for nations that have not yet agreed to address greenhouse gas emissions and provides the potential for a parallel climate agreement.

Pyrolysis reactor and fluidized bed combustion chamber

DOEpatents

Green, Norman W.

1981-01-06

A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

Method for making an energetic material

DOEpatents

Fox, Robert V [Idaho Falls, ID

2008-03-18

A method for making trinitrotoluene is described, and which includes the steps of providing a source of aqueous nitric acid having a concentration of less than about 95% by weight; mixing a surfactant with the source of aqueous nitric acid so as to dehydrate the aqueous nitric acid to produce a source of nitronium ions; providing a supercritical carbon dioxide environment; providing a source of an organic material to be nitrated to the supercritical carbon dioxide environment; and controllably mixing the source or nitronium ions with the supercritical carbon dioxide environment to nitrate the organic material and produce trinitrotoluene.

Carbon flow analysis of China's agro-ecosystem from 1980 to 2013: A perspective from substance flow analysis.

PubMed

Liu, Yu; Wang, Can; Chen, Minpeng

2017-05-01

Research on carbon cycling has attracted attention from both scientists and policy-makers. Based on material flow analysis, this study systematically budgets the carbon inputs, outputs and balance from 1980 to 2013 for China's agro-ecosystem and its sub-systems, including agricultural land use, livestock breeding and rural life. The results show that from 1980 to 2013, both the carbon input and output were growing gradually, with the carbon input doubling from 1.6PgC/year in 1980 to 3.4PgC/year in 2013, while carbon output grew from 2.2PgC/year in 1980 to 3.8PgC/year in 2013. From 1980 to 2013, the crop production system in China has remained a carbon source, and the agricultural land uses were also almost all carbon sources instead of carbon sinks. As soil carbon stock plays a very important role in deciding the function of China's agro-ecosystem as a carbon sink or source, practices that can promote carbon storage and sequestration will be an essential component of low carbon agriculture development in China. Copyright © 2016. Published by Elsevier B.V.

Understanding the effect of carbon status on stem diameter variations

PubMed Central

De Swaef, Tom; Driever, Steven M.; Van Meulebroek, Lieven; Vanhaecke, Lynn; Marcelis, Leo F. M.; Steppe, Kathy

2013-01-01

Background Carbon assimilation and leaf-to-fruit sugar transport are, along with plant water status, the driving mechanisms for fruit growth. An integrated comprehension of the plant water and carbon relationships is therefore essential to better understand water and dry matter accumulation. Variations in stem diameter result from an integrated response to plant water and carbon status and are as such a valuable source of information. Methods A mechanistic water flow and storage model was used to relate variations in stem diameter to phloem sugar loading and sugar concentration dynamics in tomato. The simulation results were compared with an independent model, simulating phloem sucrose loading at the leaf level based on photosynthesis and sugar metabolism kinetics and enabled a mechanistic interpretation of the ‘one common assimilate pool’ concept for tomato. Key Results Combining stem diameter variation measurements and mechanistic modelling allowed us to distinguish instantaneous dynamics in the plant water relations and gradual variations in plant carbon status. Additionally, the model combined with stem diameter measurements enabled prediction of dynamic variables which are difficult to measure in a continuous and non-destructive way, such as xylem water potential and phloem hydrostatic potential. Finally, dynamics in phloem sugar loading and sugar concentration were distilled from stem diameter variations. Conclusions Stem diameter variations, when used in mechanistic models, have great potential to continuously monitor and interpret plant water and carbon relations under natural growing conditions. PMID:23186836

Trihalomethane formation potential of aquatic and terrestrial fulvic and humic acids: Sorption on activated carbon.

PubMed

Abouleish, Mohamed Y Z; Wells, Martha J M

2015-07-15

Humic substances (HSs) are precursors for the formation of hazardous disinfection by-products (DBPs) during chlorination of water. Various surrogate parameters have been used to investigate the generation of DBPs by HS precursors and the removal of these precursors by activated carbon treatment. Dissolved organic carbon (DOC)- and ultraviolet absorbance (UVA254)-based isotherms are commonly reported and presumed to be good predictors of the trihalomethane formation potential (THMFP). However, THMFP-based isotherms are rarely published such that the three types of parameters have not been compared directly. Batch equilibrium experiments on activated carbon were used to generate constant-initial-concentration sorption isotherms for well-characterized samples obtained from the International Humic Substances Society (IHSS). HSs representing type (fulvic acid [FA], humic acid [HA]), origin (aquatic, terrestrial), and geographical source (Nordic, Suwannee, Peat, Soil) were examined at pH6 and pH9. THMFP-based isotherms were generated and compared to determine if DOC- and UVA254-based isotherms were good predictors of the THMFP. The sorption process depended on the composition of the HSs and the chemical nature of the activated carbon, both of which were influenced by pH. Activated carbon removal of THM-precursors was pH- and HS-dependent. In some instances, the THMFP existed after UVA254 was depleted. Copyright © 2015 Elsevier B.V. All rights reserved.

Microspheres and their methods of preparation

DOEpatents

Bose, Anima B; Yang, Junbing

2015-03-24

Carbon microspheres are doped with boron to enhance the electrical and physical properties of the microspheres. The boron-doped carbon microspheres are formed by a CVD process in which a catalyst, carbon source and boron source are evaporated, heated and deposited onto an inert substrate.

Sources and formation mechanisms of carbonaceous aerosol at a regional background site in the Netherlands: insights from a year-long radiocarbon study

NASA Astrophysics Data System (ADS)

Dusek, Ulrike; Hitzenberger, Regina; Kasper-Giebl, Anne; Kistler, Magdalena; Meijer, Harro A. J.; Szidat, Sönke; Wacker, Lukas; Holzinger, Rupert; Röckmann, Thomas

2017-03-01

We measured the radioactive carbon isotope 14C (radiocarbon) in various fractions of the carbonaceous aerosol sampled between February 2011 and March 2012 at the Cesar Observatory in the Netherlands. Based on the radiocarbon content in total carbon (TC), organic carbon (OC), water-insoluble organic carbon (WIOC), and elemental carbon (EC), we estimated the contribution of major sources to the carbonaceous aerosol. The main source categories were fossil fuel combustion, biomass burning, and other contemporary carbon, which is mainly biogenic secondary organic aerosol material (SOA). A clear seasonal variation is seen in EC from biomass burning (ECbb), with lowest values in summer and highest values in winter, but ECbb is a minor fraction of EC in all seasons. WIOC from contemporary sources is highly correlated with ECbb, indicating that biomass burning is a dominant source of contemporary WIOC. This suggests that most biogenic SOA is water soluble and that water-insoluble carbon stems mainly from primary sources. Seasonal variations in other carbon fractions are less clear and hardly distinguishable from variations related to air mass history. Air masses originating from the ocean sector presumably contain little carbonaceous aerosol from outside the Netherlands, and during these conditions measured carbon concentrations reflect regional sources. In these situations absolute TC concentrations are usually rather low, around 1.5 µg m-3, and ECbb is always very low ( ˜ 0.05 µg m-3), even in winter, indicating that biomass burning is not a strong source of carbonaceous aerosol in the Netherlands. In continental air masses, which usually arrive from the east or south and have spent several days over land, TC concentrations are on average by a factor of 3.5 higher. ECbb increases more strongly than TC to 0.2 µg m-3. Fossil EC and fossil WIOC, which are indicative of primary emissions, show a more moderate increase by a factor of 2.5 on average. An interesting case is fossil water-soluble organic carbon (WSOC, calculated as OC-WIOC), which can be regarded as a proxy for SOA from fossil precursors. Fossil WSOC has low concentrations when regional sources are sampled and increases by more than a factor of 5 in continental air masses. A longer residence time of air masses over land seems to result in increased SOA concentrations from fossil origin.

The extraction of negative carbon ions from a volume cusp ion source

NASA Astrophysics Data System (ADS)

Melanson, Stephane; Dehnel, Morgan; Potkins, Dave; McDonald, Hamish; Hollinger, Craig; Theroux, Joseph; Martin, Jeff; Stewart, Thomas; Jackle, Philip; Philpott, Chris; Jones, Tobin; Kalvas, Taneli; Tarvainen, Olli

2017-08-01

Acetylene and carbon dioxide gases are used in a filament-powered volume-cusp ion source to produce negative carbon ions for the purpose of carbon implantation for gettering applications. The beam was extracted to an energy of 25 keV and the composition was analyzed with a spectrometer system consisting of a 90° dipole magnet and a pair of slits. It is found that acetylene produces mostly C2- ions (up to 92 µA), while carbon dioxide produces mostly O- with only trace amounts of C-. Maximum C2- current was achieved with 400 W of arc power and, the beam current and composition were found to be highly dependent on the pressure in the source. The beam properties as a function of source settings are analyzed, and plasma properties are measured with a Langmuir probe. Finally, we describe testing of a new RF H- ion source, found to produce more than 6 mA of CW H- beam.

Controls on the Origin and Cycling of Riverine Dissolved Inorganic Carbon in the Brazos River, Texas

NASA Astrophysics Data System (ADS)

Zeng, F.; Masiello, C. A.; Hockaday, W. C.

2008-12-01

Rivers are generally supersaturated in CO2 with respect to the atmosphere. However, there is little agreement on the sources and turnover times of excess CO2 in river waters. This is likely due to varying dominant controls on carbon sources (e.g. geologic setting, climate, land use, or human activities). In this study, we measured carbon isotopic signatures (δ13C and Δ14C) of riverine dissolved inorganic carbon (DIC), as well as solid state cross polarization/magic angle spinning (CP/MAS) 13C nuclear magnetic resonance (NMR) of particulate organic carbon (POC), to determine carbon sources fuelling respiration of the Brazos River in Texas. We found that sources of riverine CO2 varied significantly along the length of the Brazos. In the middle Brazos (between Graham and Waco), which is partially underlain by limestone, riverine DIC had average Δ14C of 74 ‰ and δ13C of -7.5 ‰, suggesting that riverine CO2 is derived almost entirely from contemporary carbon (less than 5 years old) with little evidence of carbonate input, probably due to the damming upstream of Waco. In the lower Brazos (downstream of Bryan), riverine DIC was highly depleted in 14C (average Δ14C = -148.5 ‰) and enriched in 13C (average δ13C= -9.32 ‰), indicative of the presence of old carbonate. Since there is no carbonate bedrock in contact with the river in this area, the most likely source of old carbonate is the shell used in road and building construction throughout the 19th century. Our results suggest that the effect of human activities superimposes and even surpasses the effect of natural controls (e.g. geologic setting and climate) on C cycling in the Brazos.

Effect of carbon source on the morphology and electrochemical performances of LiFePO4/C nanocomposites.

PubMed

Liu, Shuxin; Wang, Haibin; Yin, Hengbo; Wang, Hong; He, Jichuan

2014-03-01

The carbon coated LiFePO4 (LiFePO4/C) nanocomposites materials were successfully synthesized by sol-gel method. The microstructure and morphology of LiFePO4/C nanocomposites were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The results showed that the carbon layers decomposed by different dispersant and carbon source had different graphitization degree, and the sugar could decompose to form more graphite-like structure carbon. The carbon source and heat-treatment temperature had some effect on the particle size and morphology, the sample LFP-S700 synthesized by adding sugar as carbon source at 700 degrees C had smaller particle size, uniform size distribution and spherical shape. The electrochemical behavior of LiFePO4/C nanocomposites was analyzed using galvanostatic measurements and cyclic voltammetry (CV). The results showed that the sample LFP-S700 had higher discharge specific capacities, higher apparent lithium ion diffusion coefficient and lower charge transfer resistance. The excellent electrochemical performance of sample LFP-S700 could be attributed to its high graphitization degree of carbon, smaller particle size and uniform size distribution.

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2011 CFR

2011-07-01

... affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC (as carbon...

40 CFR Table 3 to Subpart Kkkk of... - Emission Limits for Affected Sources Using the Control Efficiency/Outlet Concentration Compliance...

Code of Federal Regulations, 2010 CFR

2010-07-01

... affected source a. reduce emissions of total HAP, measured as THC (as carbon), a by 97 percent; orb. limit emissions of total HAP, measured as THC (as carbon), a to 20 ppmvd at the control device outlet and use a PTE. 2. in an existing affected source a. reduce emissions of total HAP, measured as THC (as carbon...

Identifying microbial carbon sources during ethanol and toluene biodegradation in a pilot-scale experimental aquifer system using isotopic analysis

NASA Astrophysics Data System (ADS)

Clay, S.; McLeod, H.; Smith, J. E.; Roy, J. W.; Slater, G. F.

2013-12-01

Combining ethanol with gasoline has become increasingly common in order to create more environmentally conscience transportation fuels. These blended fuels are favourable alternatives since ethanol is a non-toxic and highly labile renewable biomass-based resource which is an effective fuel oxygenate that reduces air pollution. Recent research however, has indicated that upon accidental release into groundwater systems, the preferential microbial metabolism of ethanol can cause progressively reducing conditions leading to slower biodegradation of petroleum hydrocarbons. Therefore, the presence of ethanol can result in greater persistence of BTEX compounds and longer hydrocarbon plumes in groundwater systems. Microbial biodegradation and community carbon sources coupled to aqueous geochemistry were monitored in a pilot-scale laboratory tank (80cm x 525cm x 175cm) simulating an unconfined sand aquifer. Dissolved ethanol and toluene were continuously injected into the aquifer at a controlled rate over 330 days. Carbon isotope analyses were performed on phospholipid fatty acid (PLFA) samples collected from 4 different locations along the aquifer. Initial stable carbon isotope values measured over days 160-185 in the bacterial PLFA ranged from δ13C = -10 to -21‰, which is indicative of dominant ethanol incorporation by the micro-organisms based on the isotopic signature of ethanol derived from corn, a C4 plant. A negative shift to δ13C = -10 to -30‰ observed over days 185-200, suggests a change in microbial metabolisms associated with less ethanol incorporation. This generally corresponds to a decrease in ethanol concentrations from day 40 to full attenuation at approximately day 160, and the onset of toluene depletion observed on day 120 and continuing thereafter. In addition, aqueous methane concentrations first detected on day 115 continued to rise to 0.38-0.70 mmol/L at all monitoring locations, demonstrating a significant redox shift to low energy methanogenic metabolisms. On-going archaeal lipid analyses are expected to capture the establishment of methanogenic communities and provide insight into carbon use by these communities. Furthermore, radiocarbon analysis will aid in tracking the biodegradation of ethanol and toluene. Ultimately this research aims to illustrate the preferential biodegradation of ethanol in a gasoline mixture, and identify the carbon sources utilized by an evolving microbial community using isotopic analyses to improve assessments and remediation strategies at sites contaminated with ethanol-blended fuels.

Late Mississippian (Chesterian) carbonate to carbonate-clastic cycles in the eastern Illinois Basin

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

Smith, L.B.; Read, J.F.

1994-03-01

Late Mississippian (Chesterian) rocks of the eastern Illinois Basin in Kentucky and Indiana show depositional cycles (3--20 meters thick) composed of a range of facies deposited during the transition from carbonate-dominated deposition of the Middle Mississippian to the predominantly siliciclastic regime of the Pennsylvanian. Within the basal Ste. Genevieve Formation (30--70 meters thick) there are five predominantly carbonate cycles. Cycle bases vary from thin calcareous sandstone near the northern clastic source to ooid-quartz dolomitic pelletal grainstone and mudstone further south. Massive cross-bedded and channeled ooid-skeletal grainstones represent the cycle tops and are commonly capped by caliche and subaerial breccia, particularlymore » where there was no subsequent siliciclastic deposition. The cycles are interpreted to be driven by fourth-order (400 k.y.) glacio-eustatic sea-level fluctuations based on coincidence of the calculated cycle period with the long-term eccentricity signal, the Late Mississippian onset of Gondwana glaciation and cycle correlation over more than 100 kilometers. The breccia and caliche formed during lowstands, the siliciclastics, eolianites and dolomitic pelletal grainstones are transgressive facies and the ooid-skeletal grainstones represent sea-level highstands.« less

In situ observations of the atomistic mechanisms of Ni catalyzed low temperature graphene growth.

PubMed

Patera, Laerte L; Africh, Cristina; Weatherup, Robert S; Blume, Raoul; Bhardwaj, Sunil; Castellarin-Cudia, Carla; Knop-Gericke, Axel; Schloegl, Robert; Comelli, Giovanni; Hofmann, Stephan; Cepek, Cinzia

2013-09-24

The key atomistic mechanisms of graphene formation on Ni for technologically relevant hydrocarbon exposures below 600 °C are directly revealed via complementary in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. For clean Ni(111) below 500 °C, two different surface carbide (Ni2C) conversion mechanisms are dominant which both yield epitaxial graphene, whereas above 500 °C, graphene predominantly grows directly on Ni(111) via replacement mechanisms leading to embedded epitaxial and/or rotated graphene domains. Upon cooling, additional carbon structures form exclusively underneath rotated graphene domains. The dominant graphene growth mechanism also critically depends on the near-surface carbon concentration and hence is intimately linked to the full history of the catalyst and all possible sources of contamination. The detailed XPS fingerprinting of these processes allows a direct link to high pressure XPS measurements of a wide range of growth conditions, including polycrystalline Ni catalysts and recipes commonly used in industrial reactors for graphene and carbon nanotube CVD. This enables an unambiguous and consistent interpretation of prior literature and an assessment of how the quality/structure of as-grown carbon nanostructures relates to the growth modes.

Laboratory Evaluation of Selected Ways for Determining Black Carbon Source Emissions

EPA Science Inventory

A number of studies have been conducted which compare various methods for the determination of black carbon in the atmosphere. Relatively little attention has been paid, however, to similar measurements of black carbon from different types of emission sources. Of particular int...

TOWARD ERROR ANALYSIS OF LARGE-SCALE FOREST CARBON BUDGETS

EPA Science Inventory

Quantification of forest carbon sources and sinks is an important part of national inventories of net greenhouse gas emissions. Several such forest carbon budgets have been constructed, but little effort has been made to analyse the sources of error and how these errors propagate...

A Precisely Assembled Carbon Source to Synthesize Fluorescent Carbon Quantum Dots for Sensing Probes and Bioimaging Agents.

PubMed

Qiao, Yiqiang; Luo, Dan; Yu, Min; Zhang, Ting; Cao, Xuanping; Zhou, Yanheng; Liu, Yan

2018-02-09

A broad range of carbon sources have been used to fabricate varieties of carbon quantum dots (CQDs). However, the majority of these studies concern the influence of primary structures and chemical compositions of precursors on the CQDs; it is still unclear whether or not the superstructures of carbon sources have effects on the physiochemical properties of the synthetic CQDs. In this work, the concept of molecular assembly is first introduced into the design of a new carbon source. Compared with the tropocollagen molecules, the hierarchically assembled collagen scaffolds, as a new carbon source, immobilize functional groups of the precursors through hydrogen bonds, electrostatic attraction, and hydrophobic forces. Moreover, the accumulation of functional groups in collagen self-assembly further promotes the covalent bond formation in the obtained CQDs through a hydrothermal process. Both of these two chemical superiorities give rise to high quality CQDs with enhanced emission. The assembled collagen scaffold-based CQDs with heteroatom doping exhibit superior stability, and could be further applied as effective fluorescent probes for Fe 3+ detection and cellular cytosol imaging. These findings open a wealth of possibilities to explore more nanocarbons from precursors with assembled superstructures. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for in-situ cleaning of carbon contaminated surfaces

DOEpatents

Klebanoff, Leonard E.; Grunow, Philip; Graham, Jr., Samuel

2006-12-12

Activated gaseous species generated adjacent a carbon contaminated surface affords in-situ cleaning. A device for removing carbon contamination from a surface of the substrate includes (a) a housing defining a vacuum chamber in which the substrate is located; (b) a source of gaseous species; and (c) a source of electrons that are emitted to activate the gaseous species into activated gaseous species. The source of electrons preferably includes (i) a filament made of a material that generates thermionic electron emissions; (ii) a source of energy that is connected to the filament; and (iii) an electrode to which the emitted electrons are attracted. The device is particularly suited for photolithography systems with optic surfaces, e.g., mirrors, that are otherwise inaccessible unless the system is dismantled. A method of removing carbon contaminants from a substrate surface that is housed within a vacuum chamber is also disclosed. The method employs activated gaseous species that react with the carbon contaminants to form carbon containing gaseous byproducts.

Generation and Phenotypic Characterization of Aspergillus nidulans Methylisocitrate Lyase Deletion Mutants: Methylisocitrate Inhibits Growth and Conidiation

PubMed Central

Brock, Matthias

2005-01-01

Propionate is a very abundant carbon source in soil, and many microorganisms are able to use this as the sole carbon source. Nevertheless, propionate not only serves as a carbon source for filamentous fungi but also acts as a preservative when added to glucose containing media. To solve this contradiction between carbon source and preservative effect, propionate metabolism of Aspergillus nidulans was studied and revealed the methylcitrate cycle as the responsible pathway. Methylisocitrate lyase is one of the key enzymes of that cycle. It catalyzes the cleavage of methylisocitrate into succinate and pyruvate and completes the α-oxidation of propionate. Previously, methylisocitrate lyase was shown to be highly specific for the substrate (2R,3S)-2-methylisocitrate. Here, the identification of the genomic sequence of the corresponding gene and the generation of deletion mutants is reported. Deletion mutants did not grow on propionate as sole carbon and energy source and were severely inhibited during growth on alternative carbon sources, when propionate was present. The strongest inhibitory effect was observed, when glycerol was the main carbon source, followed by glucose and acetate. In addition, asexual conidiation was strongly impaired in the presence of propionate. These effects might be caused by competitive inhibition of the NADP-dependent isocitrate dehydrogenase, because the Ki of (2R,3S)-2-methylisocitrate, the product of the methylcitrate cycle, on NADP-dependent isocitrate dehydrogenase was determined as 1.55 μM. Other isomers had no effect on enzymatic activity. Therefore, methylisocitrate was identified as a potential toxic compound for cellular metabolism. PMID:16151139

Quantifying and Mapping the Supply of and Demand for Carbon Storage and Sequestration Service from Urban Trees.

PubMed

Zhao, Chang; Sander, Heather A

2015-01-01

Studies that assess the distribution of benefits provided by ecosystem services across urban areas are increasingly common. Nevertheless, current knowledge of both the supply and demand sides of ecosystem services remains limited, leaving a gap in our understanding of balance between ecosystem service supply and demand that restricts our ability to assess and manage these services. The present study seeks to fill this gap by developing and applying an integrated approach to quantifying the supply and demand of a key ecosystem service, carbon storage and sequestration, at the local level. This approach follows three basic steps: (1) quantifying and mapping service supply based upon Light Detection and Ranging (LiDAR) processing and allometric models, (2) quantifying and mapping demand for carbon sequestration using an indicator based on local anthropogenic CO2 emissions, and (3) mapping a supply-to-demand ratio. We illustrate this approach using a portion of the Twin Cities Metropolitan Area of Minnesota, USA. Our results indicate that 1735.69 million kg carbon are stored by urban trees in our study area. Annually, 33.43 million kg carbon are sequestered by trees, whereas 3087.60 million kg carbon are emitted by human sources. Thus, carbon sequestration service provided by urban trees in the study location play a minor role in combating climate change, offsetting approximately 1% of local anthropogenic carbon emissions per year, although avoided emissions via storage in trees are substantial. Our supply-to-demand ratio map provides insight into the balance between carbon sequestration supply in urban trees and demand for such sequestration at the local level, pinpointing critical locations where higher levels of supply and demand exist. Such a ratio map could help planners and policy makers to assess and manage the supply of and demand for carbon sequestration.

Tropical forests are a net carbon source based on aboveground measurements of gain and loss

NASA Astrophysics Data System (ADS)

Baccini, A.; Walker, W.; Carvalho, L.; Farina, M.; Sulla-Menashe, D.; Houghton, R. A.

2017-10-01

The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world’s tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year-1). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year-1 and gains of 436.5 ± 31.0 Tg C year-1. Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses.

Shunting arc plasma source for pure carbon ion beam.

PubMed

Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

2012-02-01

A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

Shunting arc plasma source for pure carbon ion beam

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

Koguchi, H.; Sakakita, H.; Kiyama, S.

2012-02-15

A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm{sup 2} at the peak of the pulse.

Coupling experimental and field-based approaches to decipher carbon sources in the shell of the great scallop, Pecten maximus (L.)

NASA Astrophysics Data System (ADS)

Marchais, V.; Richard, J.; Jolivet, A.; Flye-Sainte-Marie, J.; Thébault, J.; Jean, F.; Richard, P.; Paulet, Y.-M.; Clavier, J.; Chauvaud, L.

2015-11-01

This research investigated how the carbon isotopic composition of food source (δ13Cfood) and dissolved inorganic carbon (δ13CDIC) influences the carbon isotopic composition of Pecten maximus shells (δ13Cshell) under both experimental and natural conditions. The objectives are to better understand the relationship between P. maximus and its environment, and to specifically distinguish conditions under which calcification is influenced by respired CO2 derived from food sources versus conditions in which calcification uses inorganic carbon from seawater. Laboratory experiment investigated carbon incorporation into shell carbonates by maintaining scallops under conditions where the stable carbon isotopic composition of food sources was considerably depleted (-54‰), relative to values observed in the natural environment (-21‰). Laboratory experiment ran for 78 days under three temperature conditions, 15 °C, 21 °C and 25 °C. A survey of the environmental parameters and stable carbon isotopic composition into shell carbonate of natural population of P. maximus was also realized during the same year in the Bay of Brest, France. Data collected from both laboratory experiment and the natural environment confirmed that both δ13CDIC and δ13Cfood influence δ13Cshell values and that organic carbon incorporation (CM) averages about 10% (4.3-6.8% under experimental conditions and 1.9-16.6% in the natural environment). The shift in stable carbon isotopic composition from the uptake of depleted food sources under experimental conditions realized a marked divergence in the predicted equilibrium between calcium carbonate and ambient bicarbonate, relative to the natural environment. This offset was 1.7 ± 0.6‰ for scallops in their natural environment and 2.5 ± 0.5 and 3.2 ± 0.9‰ for scallops under experimental conditions at water temperatures of 15 °C and 21 °C, respectively. The offset of 3‰ for scallops subjected to laboratory experiment could not be explained in light of growth rate but may be related to food supply and/or temperature. Food source and temperature effects may also explain the annual variation observed in CM values measured from scallops in their natural environment. CM estimation from the natural population of P. maximus varied seasonally from around 2% at the end of winter, to 12% in summer. The seasonal variation resembles variability in the carbon isotopic composition of the food sources throughout the year with an exception at the end of winter.

40 CFR 63.1103 - Source category-specific applicability, definitions, and requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... compliance schedule for the carbon black production and acetylene decomposition carbon black production... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Source...

40 CFR 63.1103 - Source category-specific applicability, definitions, and requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... compliance schedule for the carbon black production and acetylene decomposition carbon black production... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Source...

40 CFR 63.1103 - Source category-specific applicability, definitions, and requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... compliance schedule for the carbon black production and acetylene decomposition carbon black production... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Source...

40 CFR 63.1103 - Source category-specific applicability, definitions, and requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... compliance schedule for the carbon black production and acetylene decomposition carbon black production... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Source...

Significance of anoxic slope basins to occurrence of hydrocarbons along flexure trend, Gulf of Mexico: a reappraisal

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

Dinkelman, M.G.; Curry, D.J.

1987-05-01

Recently, Tertiary anoxic slope basins have been proposed as the sources for much of the oil occurring along the Flexure Trend in the Gulf of Mexico. The intraslope basins are thought to have been formed in response to salt diapirism and concomitant salt withdrawal resulting from differential sediment loading between the basins and the diapirs, as well as due to associated faulting. Of the modern intraslope basins, the black, organic-rich muds accumulating in the Orca basin have especially attracted and are suggested to be modern analogs to late Tertiary source rocks accumulated and buried across the continental slope. Although themore » organic carbon content of the anoxic sediments in the Orca basin is generally high (2 to 3%), the concentration of preserved oil-generative organic matter in these sediments is low. Rock-Eval P2 yields are usually in the range of 340 to 1620 ppm, and hydrogen indices are generally less than 100. Pyrolysis-GC and 13C-NMR data show that up to 30 + % of the organic carbon is contained in carboxyl and other oxygenated groups, which are lost during diagenesis and early catagenesis of the sediments, and that much of the remainder is aromatized and degraded. The degradation was probably by oxidation during settling through the oxic water column. The geochemical data indicate, therefore, that the bulk of the organic carbon in the Orca basin is not capable of forming oil during catagenesis. Published regional cross sections across the Texas-Louisiana continental margin commonly show a thick (0.5-4 km), continuous salt sequence, sourcing salt diapirs and ridges, to underlie the Oligocene(.)/Miocene to Pleistocene sedimentary section of the outer continental shelf and slope.« less

Biosorption behavior and mechanism of lead (II) from aqueous solution by aerobic granules (AG) and bacterial alginate (BA)

NASA Astrophysics Data System (ADS)

Wang, Lin; Li, Yu

2012-12-01

Lead (Pb) and its compounds are common pollutants in industrial wastewaters. To develop appropriate Pb2+ treatment technologies, aerobic granules (AG) and bacterial alginates (BA) were studied as alternative biosorbents to remove Pb2+ from aqueous solutions. The biosorption mechanism of AG and BA were further analyzed to determine which functional groups in AG and BA are active in Pb2+ biosorption. In this paper, the Pb2+ biosorption behavior of AG and BA was respectively investigated in batch experiments from the perspectives of the initial pH, contact time, and initial Pb2+ concentration. The results showed that biosorption of Pb2+ by AG and BA occurred within 60min at the initial Pb2+ concentrations (0-150 mg L-1). The actual saturated Pb2+ biosorption capability of AG was 101.97 mg g-1 (dry weight of aerobic granular biomass). When the initial pH was 5, the biosorption capability of AG and BA was highest at the initial Pb2+ concentrations (0-20mg L-1). During the process of Pb2+ biosorption, K+, Ca2+, and Mg2+ were released. The Ion Chromatography (IC) and Fourier Transform Infrared Spectroscopy (FTIR) further highlighted the main role of ion exchange between Ca2+ and Pb2+ and sequestration of Pb2+ with carboxyl (-COO-) of AG and BA. This analogical analysis verifies that BA is responsible for biosorption of Pb2+ by AG. At the same optimal pH, AG cultivated with different carbon source has different Pb2+ biosorption capacity. The Pb2+ biosorption by AG with sodium acetate as the sole carbon source is higher than AG with glucose as carbon source.

Two pectin lyase genes, pnl-1 and pnl-2, from Colletotrichum gloeosporioides f. sp. malvae differ in a cellulose-binding domain and in their expression during infection of Malva pusilla.

PubMed

Wei, Yangdou; Shih, Jenny; Li, Jieran; Goodwin, Paul H

2002-07-01

Two pectin lyase genes, designated pnl-1 and pnl-2, were cloned from Colletotrichum gloeosporioides f. sp. malvae, a pathogen of round-leaved mallow (Malva pusilla). pnl-1 was isolated using cDNA from infected plant material; pnl-2 was isolated using cDNA from 3-day-old mycelia grown in mallow-cell-wall extract (MCWE) broth. pnl-1 is the first pectinase gene described thus far to encode a cellulose-binding domain (CBD), which is common in cellulases and xylanases, whereas pnl-2 encodes a pectin lyase that lacks a CBD. In pure culture, pnl-1 expression could be detected when purified pectin or glucose was the sole carbon source, but not when MCWE was the sole carbon source. The lack of pnl-1 expression appeared to be due to gene repression by some unknown factor(s) in the cell-wall extract. In contrast, expression of pnl-2 was detected in cultures when MCWE, but not when purified pectin or glucose, was the sole carbon source. In infected tissue, detection of pnl-1 expression by Northern-blot hybridization and by RT-PCR began with the onset of the necrotrophic phase of infection. Expression ofpnl-2 was not detectable by Northern-blot hybridization, but was observed byRT-PCR in both the biotrophic and necrotrophic phases of infection. The differences between pnl-1 and pnl-2 (i.e. pnl-1 encoding a CBD and differences in the expression patterns of both genes) may be related to the requirements of C. gloeosporioides f. sp. malvae to be able to grow in host tissue under the different conditions present during the biotrophic and necrotrophic phases of infection.

Report: Combustion Byproducts and Their Health Effects: Summary of the 10th International Congress

PubMed Central

Dellinger, Barry; D'Alessio, Antonio; D'Anna, Andrea; Ciajolo, Anna; Gullett, Brian; Henry, Heather; Keener, Mel; Lighty, JoAnn; Lomnicki, Slawomir; Lucas, Donald; Oberdörster, Günter; Pitea, Demetrio; Suk, William; Sarofim, Adel; Smith, Kirk R.; Stoeger, Tobias; Tolbert, Paige; Wyzga, Ron; Zimmermann, Ralf

2008-01-01

Abstract The 10th International Congress on Combustion Byproducts and their Health Effects was held in Ischia, Italy, from June 17–20, 2007. It is sponsored by the US NIEHS, NSF, Coalition for Responsible Waste Incineration (CRWI), and Electric Power Research Institute (EPRI). The congress focused on: the origin, characterization, and health impacts of combustion-generated fine and ultrafine particles; emissions of mercury and dioxins, and the development/application of novel analytical/diagnostic tools. The consensus of the discussion was that particle-associated organics, metals, and persistent free radicals (PFRs) produced by combustion sources are the likely source of the observed health impacts of airborne PM rather than simple physical irritation of the particles. Ultrafine particle-induced oxidative stress is a likely progenitor of the observed health impacts, but important biological and chemical details and possible catalytic cycles remain unresolved. Other key conclusions were: (1) In urban settings, 70% of airborne fine particles are a result of combustion emissions and 50% are due to primary emissions from combustion sources, (2) In addition to soot, combustion produces one, possibly two, classes of nanoparticles with mean diameters of ~10 nm and ~1 nm. (3) The most common metrics used to describe particle toxicity, viz. surface area, sulfate concentration, total carbon, and organic carbon, cannot fully explain observed health impacts, (4) Metals contained in combustion-generated ultrafine and fine particles mediate formation of toxic air pollutants such as PCDD/F and PFRs. (5) The combination of metal-containing nanoparticles, organic carbon compounds, and PFRs can lead to a cycle generating oxidative stress in exposed organisms. PMID:22476005

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

Holdridge, D. J.

Global Warming and Methane--Global warming, an increase in Earth's near-surface temperature, is believed to result from the buildup of what scientists refer to as ''greenhouse gases.'' These gases include water vapor, carbon dioxide, methane, nitrous oxide, ozone, perfluorocarbons, hydrofluoro-carbons, and sulfur hexafluoride. Greenhouse gases can absorb outgoing infrared (heat) radiation and re-emit it back to Earth, warming the surface. Thus, these gases act like the glass of a greenhouse enclosure, trapping infrared radiation inside and warming the space. One of the more important greenhouse gases is the naturally occurring hydrocarbon methane. Methane, a primary component of natural gas, is themore » second most important contributor to the greenhouse effect (after carbon dioxide). Natural sources of methane include wetlands, fossil sources, termites, oceans, fresh-waters, and non-wetland soils. Methane is also produced by human-related (or anthropogenic) activities such as fossil fuel production, coal mining, rice cultivation, biomass burning, water treatment facilities, waste management operations and landfills, and domesticated livestock operations (Figure 1). These anthropogenic activities account for approximately 70% of the methane emissions to the atmosphere. Methane is removed naturally from the atmosphere in three ways. These methods, commonly referred to as sinks, are oxidation by chemical reaction with tropospheric hydroxyl ion, oxidation within the stratosphere, and microbial uptake by soils. In spite of their important role in removing excess methane from the atmosphere, the sinks cannot keep up with global methane production. Methane concentrations in the atmosphere have increased by 145% since 1800. Increases in atmospheric methane roughly parallel world population growth, pointing to anthropogenic sources as the cause (Figure 2). Increases in the methane concentration reduce Earth's natural cooling efficiency by trapping more of the outgoing terrestrial infrared radiation, increasing the near-surface temperature.« less

Observation of carbonaceous aerosols and carbon monoxide in Mid-Atlantic region: Seasonal and inter-annual variations

NASA Astrophysics Data System (ADS)

Chen, L. A.; Doddridge, B. G.; Doddridge, B. G.; Dickerson, R. R.; Dickerson, R. R.

2001-05-01

As part of Maryland Aerosol Research and Characterization (MARCH-Atlantic) study, a long-term monitoring of ambient elemental and organic carbon (EC and OC) aerosols has been made at Fort Meade, MD (39.16° N 76.51° W; elevation 46 m MSL), a suburban site within the Baltimore-Washington (B-W) corridor, since July 1999. 24-hr average EC and OC are measured every day during the season-representative months (July 1999, October 1999, January 2000, April 2000 and July 2000). Carbon monoxide (CO) was also measured nearly continuously over the period. Strong correlation between EC and CO (r = 0.7 ~ 0.9) in every month suggests common or proximate sources, likely traffic emissions. The EC versus CO slope, however, varies in different seasons and is found to increase nonlinearly with the ambient temperature. EC source strength may peak in summer. OC shows strong correlation with EC (r ~ 0.95) only in winter, suggesting that OC is also of the same primary sources during wintertime. The Interagency Monitoring of Protected Visual Environments (IMPROVE) network has been measuring EC and OC around the United States since 1988. The FME data during July 1999 are also compared with simultaneous measurements at nearby IMPROVE sites, showing B-W corridor could be a major contributor to the carbonaceous aerosols in the Mid-Atlantic region. A decreasing trend of EC level is found in three IMPROVE sites in this region. This actually agrees with the decreasing trend of CO observed previously at Big Meadow, Shenandoah National Park if CO and EC are both influenced by traffic emissions.

Identification of a Lactate-Quinone Oxidoreductase in Staphylococcus aureus that is Essential for Virulence

PubMed Central

Fuller, James R.; Vitko, Nicholas P.; Perkowski, Ellen F.; Scott, Eric; Khatri, Dal; Spontak, Jeffrey S.; Thurlow, Lance R.; Richardson, Anthony R.

2011-01-01

Staphylococcus aureus is an important human pathogen commonly infecting nearly every host tissue. The ability of S. aureus to resist innate immunity is critical to its success as a pathogen, including its propensity to grow in the presence of host nitric oxide (NO·). Upon exogenous NO· exposure, S. aureus immediately excretes copious amounts of L-lactate to maintain redox balance. However, after prolonged NO·-exposure, S. aureus reassimilates L-lactate specifically and in this work, we identify the enzyme responsible for this L-lactate-consumption as a L-lactate-quinone oxidoreductase (Lqo, SACOL2623). Originally annotated as Mqo2 and thought to oxidize malate, we show that this enzyme exhibits no affinity for malate but reacts specifically with L-lactate (KM = ∼330 μM). In addition to its requirement for reassimilation of L-lactate during NO·-stress, Lqo is also critical to respiratory growth on L-lactate as a sole carbon source. Moreover, Δlqo mutants exhibit attenuation in a murine model of sepsis, particularly in their ability to cause myocarditis. Interestingly, this cardiac-specific attenuation is completely abrogated in mice unable to synthesize inflammatory NO· (iNOS−/−). We demonstrate that S. aureus NO·-resistance is highly dependent on the availability of a glycolytic carbon sources. However, S. aureus can utilize the combination of peptides and L-lactate as carbon sources during NO·-stress in an Lqo-dependent fashion. Murine cardiac tissue has markedly high levels of L-lactate in comparison to renal or hepatic tissue consistent with the NO·-dependent requirement for Lqo in S. aureus myocarditis. Thus, Lqo provides S. aureus with yet another means of replicating in the presence of host NO·. PMID:22919585

Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of particulate matter from wood and dung cooking fires, brick kilns, generators, trash and crop residue burning

NASA Astrophysics Data System (ADS)

Stone, Elizabeth; Jayarathne, Thilina; Stockwell, Chelsea; Christian, Ted; Bhave, Prakash; Siva Praveen, Puppala; Panday, Arnico; Adhikari, Sagar; Maharjan, Rashmi; Goetz, Doug; DeCarlo, Peter; Saikawa, Eri; Yokelson, Robert

2016-04-01

The Nepal Ambient Monitoring and Source Testing Experiment (NAMASTE) field campaign targeted the in situ characterization of widespread and under-sampled combustion sources. In Kathmandu and the Terai, southern Nepal's flat plains, samples of fine particulate matter (PM2.5) were collected from wood and dung cooking fires (n = 22), generators (n = 2), groundwater pumps (n = 2), clamp kilns (n = 3), zig-zag kilns (n = 3), trash burning (n = 4), one heating fire, and one crop residue fire. Co-located measurements of carbon dioxide, carbon monoxide, and volatile organic compounds allowed for the application of the carbon mass balance approach to estimate emission factors for PM2.5, elemental carbon, organic carbon, and water-soluble inorganic ions. Organic matter was chemically speciated using gas chromatography - mass spectrometry for polycyclic aromatic hydrocarbons, sterols, n-alkanes, hopanes, steranes, and levoglucosan, which accounted for 2-8% of the measured organic carbon. These data were used to develop molecular-marker based profiles for use in source apportionment modeling. This study provides quantitative emission factors for particulate matter and its constituents for many important combustion sources in Nepal and South Asia.

The effect of carbon chain length of starting materials on the formation of carbon dots and their optical properties

NASA Astrophysics Data System (ADS)

Pan, Xiaohua; Zhang, Yan; Sun, Xiaobo; Pan, Wei; Yu, Guifeng; Si, Shuxin; Wang, Jinping

2018-04-01

Carbon dots (CDs) have attracted increasing attention due to their high performances and potential applications in wide range of areas. However, their emission mechanism is not clear so far. In order to reveal more factors contributing to the emission of CDs, the effect of carbon chain length of starting materials on the formation of CDs and their optical properties was experimentally investigated in this work. In order to focus on the effect of carbon chain length, the starting materials with C, O, N in fully identical forms and only carbon chain lengths being different were selected for synthesizing CDs, including citric acid (CA) and adipic acid (AA) as carbon sources, and diamines with different carbon chain lengths (H2N(CH2)nNH2, n = 2, 4, 6) as nitrogen sources, as well as ethylenediamine (EDA) as nitrogen source and diacids with different carbon chain lengths (HOOC(CH2)nCOOH, n = 0, 2, 4, 6) as carbon sources. Therefore, the effect of carbon chain length of starting materials on the formation and optical properties of CDs can be systematically investigated by characterizing and comparing the structures and optical properties of as-prepared nine types of CDs. Moreover, the density of –NH2 on the surface of the CDs was quantitatively detected by a spectrophotometry so as to elucidate the relationship between the –NH2 related surface state and the optical properties.

Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups

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

Wang, Hao; Wang, Yun; Dai, Xiao

2015-08-01

In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility.

Carbon transfer from magnesia-graphite ladle refractories to ultra-low carbon steel

NASA Astrophysics Data System (ADS)

Russo, Andrew Arthur

Ultra-low carbon steels are utilized in processes which require maximum ductility. Increases in interstitial carbon lower the ductility of steel; therefore, it is important to examine possible sources of carbon. The refractory ladle lining is one such source. Ladle refractories often contain graphite for its desirable thermal shock and slag corrosion resistance. This graphite is a possible source of carbon increase in ultra-low carbon steels. The goal of this research is to understand and evaluate the mechanisms by which carbon transfers to ultra-low carbon steel from magnesia-graphite ladle refractory. Laboratory dip tests were performed in a vacuum induction furnace under an argon atmosphere to investigate these mechanisms. Commercial ladle refractories with carbon contents between 4-12 wt% were used to investigate the effect of refractory carbon content. Slag-free dip tests and slag-containing dip tests with varying MgO concentrations were performed to investigate the influence of slag. Carbon transfer to the steel was controlled by steel penetrating into the refractory and dissolving carbon in dip tests where no slag was present. The rate limiting step for this mechanism is convective mass transport of carbon into the bulk steel. No detectable carbon transfer occurred in dip tests with 4 and 6 wt%C refractories without slag because no significant steel penetration occurred. Carbon transfer was controlled by the corrosion of refractory by slag in dip tests where slag was present.

Microbially mediated carbon mineralization: Geoengineering a carbon-neutral mine

NASA Astrophysics Data System (ADS)

Power, I. M.; McCutcheon, J.; Harrison, A. L.; Wilson, S. A.; Dipple, G. M.; Southam, G.

2013-12-01

Ultramafic and mafic mine tailings are a potentially valuable feedstock for carbon mineralization, affording the mining industry an opportunity to completely offset their carbon emissions. Passive carbon mineralization has previously been documented at the abandoned Clinton Creek asbestos mine, and the active Diavik diamond mine and Mount Keith nickel mine, yet the majority of tailings remain unreacted. Examples of microbe-carbonate interactions at each mine suggest that biological pathways could be harnessed to promote carbon mineralization. In suitable environmental conditions, microbes can mediate geochemical processes to accelerate mineral dissolution, increase the supply of carbon dioxide (CO2), and induce carbonate precipitation, all of which may accelerate carbon mineralization. Tailings mineralogy and the availability of a CO2 point source are key considerations in designing tailings storage facilities (TSF) for optimizing carbon mineralization. We evaluate the efficacy of acceleration strategies including bioleaching, biologically induced carbonate precipitation, and heterotrophic oxidation of waste organics, as well as abiotic strategies including enhancing passive carbonation through modifying tailings management practices and use of CO2 point sources (Fig. 1). With the aim of developing carbon-neutral mines, implementation of carbon mineralization strategies into TSF design will be driven by economic incentives and public pressure for environmental sustainability in the mining industry. Figure 1. Schematic illustrating geoengineered scenarios for carbon mineralization of ultramafic mine tailings. Scenarios A and B are based on non-point and point sources of CO2, respectively.

Social Network and Content Analysis of the North American Carbon Program as a Scientific Community of Practice

NASA Technical Reports Server (NTRS)

Brown, Molly E.; Ihli, Monica; Hendrick, Oscar; Delgado-Arias, Sabrina; Escobar, Vanessa M.; Griffith, Peter

2015-01-01

The North American Carbon Program (NACP) was formed to further the scientific understanding of sources, sinks, and stocks of carbon in Earth's environment. Carbon cycle science integrates multidisciplinary research, providing decision-support information for managing climate and carbon-related change across multiple sectors of society. This investigation uses the conceptual framework of com-munities of practice (CoP) to explore the role that the NACP has played in connecting researchers into a carbon cycle knowledge network, and in enabling them to conduct physical science that includes ideas from social science. A CoP describes the communities formed when people consistently engage in shared communication and activities toward a common passion or learning goal. We apply the CoP model by using keyword analysis of abstracts from scientific publications to analyze the research outputs of the NACP in terms of its knowledge domain. We also construct a co-authorship network from the publications of core NACP members, describe the structure and social pathways within the community. Results of the content analysis indicate that the NACP community of practice has substantially expanded its research on human and social impacts on the carbon cycle, contributing to a better understanding of how human and physical processes interact with one another. Results of the co-authorship social network analysis demonstrate that the NACP has formed a tightly connected community with many social pathways through which knowledge may flow, and that it has also expanded its network of institutions involved in carbon cycle research over the past seven years.

Detection of Evolved Carbon Dioxide in the Rocknest Eolian Bedform by the Sample Analysis at Mars(SAM) Instrument at the Mars Curiosity Landing Site

NASA Technical Reports Server (NTRS)

Sutter, B.; Archer, D.; McAdam, A.; Franz, H.; Ming, D. W.; Eigenbrode, J. L.; Glavin, D. P.; Mahaffy, P.; Stern, J.; Navarro-Gonzalez, R.

2013-01-01

The Sample Analysis at Mars (SAM) instrument detected four releases of carbon dioxide (CO2) that ranged from 100 to 700 C from the Rocknest eolian bedform material (Fig. 1). Candidate sources of CO2 include adsorbed CO2, carbonate(s), combusted organics that are either derived from terrestrial contamination and/or of martian origin, occluded or trapped CO2, and other sources that have yet to be determined. The Phoenix Lander s Thermal Evolved Gas Analyzer (TEGA) detected two CO2 releases (400-600, 700-840 C) [1,2]. The low temperature release was attributed to Fe- and/or Mg carbonates [1,2], per-chlorate interactions with carbonates [3], nanophase carbonates [4] and/or combusted organics [1]. The high temperature CO2 release was attributed to a calcium bearing carbonate [1,2]. No evidence of a high temperature CO2 release similar to the Phoenix material was detected in the Rocknest materials by SAM. The objectives of this work are to evaluate the temperature and total contribution of each Rocknest CO2 release and their possible sources. Four CO2 releases from the Rocknest material were detected by SAM. Potential sources of CO2 are adsorbed CO2, (peak 1) and Fe/Mg carbonates (peak 4). Only a fraction of peaks 2 and 3 (0.01 C wt.%) may be partially attributed to combustion of organic contamination. Meteoritic organics mixed in the Rocknest bedform could be present, but the peak 2 and 3 C concentration (approx.0.21 C wt. %) is likely too high to be attributed solely to meteoritic organic C. Other inorganic sources of C such as interactions of perchlorates and carbonates and sources yet to be identified will be evaluated to account for CO2 released from the thermal decomposition of Rocknest material.

Management Impacts on Carbon Dynamics in a Sierra Nevada Mixed Conifer Forest

PubMed Central

Dore, Sabina; Fry, Danny L.; Collins, Brandon M.; Vargas, Rodrigo; York, Robert A.; Stephens, Scott L.

2016-01-01

Forest ecosystems can act as sinks of carbon and thus mitigate anthropogenic carbon emissions. When forests are actively managed, treatments can alter forests carbon dynamics, reducing their sink strength and switching them from sinks to sources of carbon. These effects are generally characterized by fast temporal dynamics. Hence this study monitored for over a decade the impacts of management practices commonly used to reduce fire hazards on the carbon dynamics of mixed-conifer forests in the Sierra Nevada, California, USA. Soil CO2 efflux, carbon pools (i.e. soil carbon, litter, fine roots, tree biomass), and radial tree growth were compared among un-manipulated controls, prescribed fire, thinning, thinning followed by fire, and two clear-cut harvested sites. Soil CO2 efflux was reduced by both fire and harvesting (ca. 15%). Soil carbon content (upper 15 cm) was not significantly changed by harvest or fire treatments. Fine root biomass was reduced by clear-cut harvest (60–70%) but not by fire, and the litter layer was reduced 80% by clear-cut harvest and 40% by fire. Thinning effects on tree growth and biomass were concentrated in the first year after treatments, whereas fire effects persisted over the seven-year post-treatment period. Over this period, tree radial growth was increased (25%) by thinning and reduced (12%) by fire. After seven years, tree biomass returned to pre-treatment levels in both fire and thinning treatments; however, biomass and productivity decreased 30%-40% compared to controls when thinning was combined with fire. The clear-cut treatment had the strongest impact, reducing ecosystem carbon stocks and delaying the capacity for carbon uptake. We conclude that post-treatment carbon dynamics and ecosystem recovery time varied with intensity and type of treatments. Consequently, management practices can be selected to minimize ecosystem carbon losses while increasing future carbon uptake, resilience to high severity fire, and climate related stresses. PMID:26918460

Can carbon offsetting pay for upland ecological restoration?

NASA Astrophysics Data System (ADS)

Worrall, F.

2012-04-01

Upland peat soils represent a large terrestrial carbon store and as such have the potential to be either an ongoing net sink of carbon or a significant net source of carbon. In the UK many upland peats are managed for a range of purposes but these purposes have rarely included carbon stewardship. However, there is now an opportunity to consider whether management practices could be altered to enhance storage of carbon in upland peats. Further, there are now voluntary and regulated carbon trading schemes operational throughout Europe that mean stored carbon, if verified, could have an economic and tradeable value. This means that new income streams could become available for upland management. The 'Sustainable Uplands' RELU project has developed a model for calculating carbon fluxes from peat soils that covers all carbon uptake and release pathways (e.g. fluvial and gaseous pathways). The model has been developed so that the impact of common management options within UK upland peats can be considered. The model was run for a decade from 1997-2006 and applied to an area of 550 km2 of upland peat soils in the Peak District. The study estimates that the region is presently a net sink of -62 Ktonnes CO2 equivalent at an average export of -136 tonnes CO2 equivalent/km2/yr.. If management interventions were targeted across the area the total sink could increase to -160 Ktonnes CO2/yr at an average export of -219 tonnes CO2 equivalent/km2/yr. However, not all interventions resulted in a benefit; some resulted in increased losses of CO2 equivalents. Given present costs of peatland restoration and value of carbon offsets, the study suggests that 51% of those areas, where a carbon benefit was estimated by modelling for targeted action of management interventions, would show a profit from carbon offsetting within 30 years. However, this percentage is very dependent upon the price of carbon used.

Contributions of wildland fire to terrestrial ecosystem carbon dynamics in North America from 1990 to 2012

USGS Publications Warehouse

Chen, Guangsheng; Hayes, Daniel J.; McGuire, A. David

2017-01-01

Burn area and the frequency of extreme fire events have been increasing during recent decades in North America, and this trend is expected to continue over the 21st century. While many aspects of the North American carbon budget have been intensively studied, the net contribution of fire disturbance to the overall net carbon flux at the continental scale remains uncertain. Based on national scale, spatially explicit and long-term fire data, along with the improved model parameterization in a process-based ecosystem model, we simulated the impact of fire disturbance on both direct carbon emissions and net terrestrial ecosystem carbon balance in North America. Fire-caused direct carbon emissions were 106.55 ± 15.98 Tg C/yr during 1990–2012; however, the net ecosystem carbon balance associated with fire was −26.09 ± 5.22 Tg C/yr, indicating that most of the emitted carbon was resequestered by the terrestrial ecosystem. Direct carbon emissions showed an increase in Alaska and Canada during 1990–2012 as compared to prior periods due to more extreme fire events, resulting in a large carbon source from these two regions. Among biomes, the largest carbon source was found to be from the boreal forest, primarily due to large reductions in soil organic matter during, and with slower recovery after, fire events. The interactions between fire and environmental factors reduced the fire-caused ecosystem carbon source. Fire disturbance only caused a weak carbon source as compared to the best estimate terrestrial carbon sink in North America owing to the long-term legacy effects of historical burn area coupled with fast ecosystem recovery during 1990–2012.

Online single particle measurements of black carbon coatings, structure and optical properties

NASA Astrophysics Data System (ADS)

Allan, James; Liu, Dantong; Taylor, Jonathan; Flynn, Michael; Williams, Paul; Morgan, William; Whitehead, James; Alfarra, Rami; McFiggans, Gordon; Coe, Hugh

2016-04-01

The impacts of black carbon on meteorology and climate remain a major source of uncertainty, owing in part to the complex relationship between the bulk composition of the particulates and their optical properties. A particular complication stems from how light interacts with particles in response to the microphysical configuration and any 'coatings', i.e. non-black carbon material that is either co-emitted or subsequently obtained through atmospheric processing. This may cause the particle to more efficiently absorb or scatter light and may even change the sign of its radiative forcing potential. While much insight has been gained through measurements of bulk aerosol properties, either while suspended or after collection on a filter or impactor substrate, this does not provide a complete picture and thus may not adequately constrain the system. Here we present an overview of recent work to better constrain the properties of black carbon using online, in situ measurements of single particles, primarily using a Single Particle Soot Photometer (SP2). We have developed novel methods of inverting the data produced and combining the different metrics derived so as to give the most effective insights into black carbon sources, processes and properties. We have also used this measurement in conjunction with other instruments (sometimes in series) and used the data to challenge many commonly used models of optical properties such as core-shell Mie, Rayleigh-Debeye-Gans and effective medium. This work has been carried out in a variety of atmospheric environments and with laboratory-produced soots, e.g. from a diesel engine rig. Highlights include the finding that with real-world atmospheric aerosols, bulk optical measurements may be insufficient to derive brown carbon parameters without detailed morphological data. We also show that the enhancement of absorption for both ambient and laboratory generated particles only occurs after the coating mass fraction reaches a certain threshold, something that may explain some apparently contradictory results from field measurements. These findings should help to inform atmospheric black carbon models and reduce uncertainties when evaluating its impacts.

Development of a stationary carbon emission inventory for Shanghai using pollution source census data

NASA Astrophysics Data System (ADS)

Li, Xianzhe; Jiang, Ping; Zhang, Yan; Ma, Weichun

2016-12-01

This study utilizes 521,631 activity data points from the 2007 Shanghai Pollution Source Census to compile a stationary carbon emission inventory for Shanghai. The inventory generated from our dataset shows that a large portion of Shanghai's total energy use consists of coal-oriented energy consumption. The electricity and heat production industries, iron and steel mills, and the petroleum refining industry are the main carbon emitters. In addition, most of these industries are located in Baoshan District, which is Shanghai's largest contributor of carbon emissions. Policy makers can use the enterpriselevel carbon emission inventory and the method designed in this study to construct sound carbon emission reduction policies. The carbon trading scheme to be established in Shanghai based on the developed carbon inventory is also introduced in this paper with the aim of promoting the monitoring, reporting and verification of carbon trading. Moreover, we believe that it might be useful to consider the participation of industries, such as those for food processing, beverage, and tobacco, in Shanghai's carbon trading scheme. Based on the results contained herein, we recommend establishing a comprehensive carbon emission inventory by inputting data from the pollution source census used in this study.

Influence of natural and novel organic carbon sources on denitrification in forest, degraded urban, and restored streams

EPA Science Inventory

Organic carbon is important in regulating ecosystem function, and its source and abundance may be altered by urbanization. We investigated shifts in organic carbon quantity and quality associated with urbanization and ecosystem restoration, and its potential effects on denitrific...

The Potential Role of Formate for Synthesis and Life in Serpentinization Systems

NASA Astrophysics Data System (ADS)

Lang, S. Q.; Frueh-Green, G. L.; Bernasconi, S. M.; Brazelton, W. J.; McGonigle, J. M.

2016-12-01

The high hydrogen concentrations produced during water-rock serpentinization reactions provide abundant thermodynamic energy that can drive the synthesis of organic compounds both biotically and abiotically. We investigated the synthesis of abiotic carbon and the metabolic pathways of the microbial inhabitants of the high energy but low diversity serpentinite-hosted Lost City Hydrothermal Field. High concentrations of the organic acid formate can be attributed to two sources. In some locations formate lacks detectable 14C, demonstrating it was formed abiotically from mantle-derived CO2. In other locations there is an additional modern contribution to the formate pool, potentially indicating active cycling with modern seawater dissolved inorganic carbon by microorganisms. The presence of this carbon source is likely critical for the survival of the subsurface microbial communities that inhabit alkaline serpentinization environments, where inorganic carbon is severely limited. Archaeal lipids produced by the Lost City Methanosarcinales (LCMS) also largely lack 14C, requiring their carbon source to be similarly 14C-free. Metagenomic evidence suggests that the LCMS could use formate for methanogenesis and, altogether, the data suggests that these organisms cannot rely on inorganic carbon as their carbon source and substrate for methanogenesis. Considering the lack of dissolved inorganic carbon in this system, the ability to utilize formate may have been a key evolutionary adaptation for survival in serpentinite-hosted environments. In the Lost City system, the LCMS apparently rely upon an abiotically produced organic carbon source, which may enable the Lost City microbial ecosystem to survive in the absence of photosynthesis or its byproducts.

Tracking Nonpoint Source Nitrogen and Carbon in Watersheds of Chesapeake Bay

NASA Astrophysics Data System (ADS)

Kaushal, S.; Pennino, M. J.; Duan, S.; Blomquist, J.

2012-12-01

Humans have altered nitrogen and carbon cycles in rivers regionally with important impacts on coastal ecosystems. Nonpoint source nitrogen pollution is a leading contributor to coastal eutrophication and hypoxia. Shifts in sources of carbon impact downstream ecosystem metabolism and fate and transport of contaminants in coastal zones. We used a combination of stable isotopes and optical tracers to investigate fate and transport of nitrogen and carbon sources in tributaries of the largest estuary in the U.S., the Chesapeake Bay. We analyzed isotopic composition of water samples from major tributaries including the Potomac River, Susquehanna River, Patuxent River, and Choptank River during routine and storm event sampling over multiple years. A positive correlation between δ15N-NO3- and δ18O-NO3- in the Potomac River above Washington D.C. suggested denitrification or biological uptake in the watershed was removing agriculturally-derived N during summer months. In contrast, the Patuxent River in Maryland showed elevated δ15N-NO3- (5 - 12 per mil) with no relationship to δ18O-NO3- suggesting the importance of wastewater sources. From the perspective of carbon sources, there were distinct isotopic values of the δ13C-POM of particulate organic matter and fluorescence excitation emission matrices (EEMS) for rivers influenced by their dominant watershed land use. EEMS showed that there were increases in the humic and fulvic fractions of dissolved organic matter during spring floods, particularly in the Potomac River. Stable isotopic values of δ13C-POM also showed rapid depletion suggesting terrestrial carbon "pulses" in the Potomac River each spring. The δ15N-POM peaked to 10 - 15 per mil each spring suggested a potential manure source or result of biological processing within the watershed. Overall, there were considerable changes in sources and transformations of nitrogen and carbon that varied across rivers and that contribute to nitrogen and carbon loads. Anticipating changes in sources and transformations will be critical for effectively managing nonpoint pollution and ecosystem services such as drinking water quality and coastal habitat.

Contributions of Phosphorus from Groundwater to Streams in the Piedmont, Blue Ridge, and Valley and Ridge Physiographic Provinces, Eastern United States

USGS Publications Warehouse

Denver, Judith M.; Cravotta,, Charles A.; Ator, Scott W.; Lindsey, Bruce D.

2011-01-01

Phosphorus from natural and human sources is likely to be discharged from groundwater to streams in certain geochemical environments. Water-quality data collected from 1991 through 2007 in paired networks of groundwater and streams in different hydrogeologic and land-use settings of the Piedmont, Blue Ridge, and Valley and Ridge Physiographic Provinces in the eastern United States were compiled and analyzed to evaluate the sources, fate, and transport of phosphorus. The median concentrations of phosphate in groundwater from the crystalline and siliciclastic bedrock settings (0.017 and 0.020 milligrams per liter, respectively) generally were greater than the median for the carbonate setting (less than 0.01 milligrams per liter). In contrast, the median concentrations of dissolved phosphate in stream base flow from the crystalline and siliciclastic bedrock settings (0.010 and 0.014 milligrams per liter, respectively) were less than the median concentration for base-flow samples from the carbonate setting (0.020 milligrams per liter). Concentrations of phosphorus in many of the stream base-flow and groundwater samples exceeded ecological criteria for streams in the region. Mineral dissolution was identified as the dominant source of phosphorus in the groundwater and stream base flow draining crystalline or siliciclastic bedrock in the study area. Low concentrations of dissolved phosphorus in groundwater from carbonate bedrock result from the precipitation of minerals and (or) from sorption to mineral surfaces along groundwater flow paths. Phosphorus concentrations are commonly elevated in stream base flow in areas underlain by carbonate bedrock, however, presumably derived from in-stream sources or from upland anthropogenic sources and transported along short, shallow groundwater flow paths. Dissolved phosphate concentrations in groundwater were correlated positively with concentrations of silica and sodium, and negatively with alkalinity and concentrations of calcium, magnesium, chloride, nitrate, sulfate, iron, and aluminum. These associations can result from the dissolution of alkali feldspars containing phosphorus; the precipitation of apatite; the precipitation of calcite, iron hydroxide, and aluminum hydroxide with associated sorption of phosphate ions; and the potential for release of phosphate from iron-hydroxide and other iron minerals under reducing conditions. Anthropogenic sources of phosphate such as fertilizer and manure and processes such as biological uptake, evapotranspiration, and dilution also affect phosphorus concentrations. The phosphate concentrations in surface water were not correlated with the silica concentration, but were positively correlated with concentrations of major cations and anions, including chloride and nitrate, which could indicate anthropogenic sources and effects of evapotranspiration on surface-water quality. Mixing of older, mineralized groundwater with younger, less mineralized, but contaminated groundwater was identified as a critical factor affecting the quality of stream base flow. In-stream processing of nutrients by biological processes also likely increases the phosphorus concentration in surface waters. Potential geologic contributions of phosphorus to groundwater and streams may be an important watershed-management consideration in certain hydrogeologic and geochemical environments. Geochemical controls effectively limit phosphorus transport through groundwater to streams in areas underlain by carbonate rocks; however, in crystalline and siliciclastic settings, phosphorus from mineral or human sources may be effectively transported by groundwater and contribute a substantial fraction to base-flow stream loads.

The air, carbon, water synergies and trade-offs in China's natural gas industry

NASA Astrophysics Data System (ADS)

Qin, Y.; Mauzerall, D. L.; Höglund-Isaksson, L.; Wagner, F.; Byers, E.

2017-12-01

Both energy production and consumption can simultaneously affect regional air quality, local water stress, and the global climate. Identifying air, carbon and water impacts of various energy sources and end-uses is important in determining the relative merits of various energy policies. Here, we examine the air-carbon-water interdependencies of China's six major natural gas source choices (domestic conventional natural gas, domestic coal-based synthetic natural gas (SNG), domestic shale gas, imported liquefied natural gas, imported Russian pipeline gas, and imported Central Asian pipeline gas) and three end-use coal-to-gas deployment strategies (with substitution strategies that focus in turn on air quality, carbon, and water) in 2020. On the supply side, we find that gas sources other than SNG offer national air-carbon-water co-benefits. However, we find striking air-carbon/water trade-offs for SNG at the national scale. Moreover, the use of SNG significantly increases water demand and carbon emissions in regions already suffering from the most severe water stress and the highest per capita carbon footprint. On the end-use side, gas substitution for coal can result in enormous variations in air quality, carbon, and water impacts, with notable air-carbon synergies but air-water trade-offs. Our study finds that, except for SNG, end-use choices generally have a much larger influence on air quality, carbon emissions and water use than do gas source choices. Simultaneous consideration of air, carbon, and water impacts is necessary in designing both beneficial energy development and deployment policies.

A Broad Bank Lidar for Precise Atmospheric CO2 Column Absorption Measurement from Space

NASA Technical Reports Server (NTRS)

Georgieva, E. M.; Heaps, W. S.; Huang, W.

2010-01-01

Accurate global measurement of carbon dioxide column with the aim of discovering and quantifying unknown sources and sinks has been a high priority for the last decade. In order to uncover the "missing sink" that is responsible for the large discrepancies in the budget the critical precision for a measurement from space needs to be on the order of 1 ppm. To better understand the CO2 budget and to evaluate its impact on global warming the National Research Council (NRC) in its recent decadal survey report (NACP) to NASA recommended a laser based total CO2 mapping mission in the near future. That's the goal of Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission - to significantly enhance the understanding of the role of CO2 in the global carbon cycle. Our current goal is to develop an ultra precise, inexpensive new lidar system for column measurements of CO2 changes in the lower atmosphere that uses a Fabry-Perot interferometer based system as the detector portion of the instrument and replaces the narrow band laser commonly used in lidars with a high power broadband source. This approach reduces the number of individual lasers used in the system and considerably reduces the risk of failure. It also tremendously reduces the requirement for wavelength stability in the source putting this responsibility instead on the Fabry- Perot subsystem.

Thermal Conductivity of Single-Walled Carbon Nanotube with Internal Heat Source Studied by Molecular Dynamics Simulation

NASA Astrophysics Data System (ADS)

Li, Yuan-Wei; Cao, Bing-Yang

2013-12-01

The thermal conductivity of (5, 5) single-walled carbon nanotubes (SWNTs) with an internal heat source is investigated by using nonequilibrium molecular dynamics (NEMD) simulation incorporating uniform heat source and heat source-and-sink schemes. Compared with SWNTs without an internal heat source, i.e., by a fixed-temperature difference scheme, the thermal conductivity of SWNTs with an internal heat source is much lower, by as much as half in some cases, though it still increases with an increase of the tube length. Based on the theory of phonon dynamics, a function called the phonon free path distribution is defined to develop a simple one-dimensional heat conduction model considering an internal heat source, which can explain diffusive-ballistic heat transport in carbon nanotubes well.

Catabolism and biotechnological applications of cholesterol degrading bacteria.

PubMed

García, J L; Uhía, I; Galán, B

2012-11-01

Cholesterol is a steroid commonly found in nature with a great relevance in biology, medicine and chemistry, playing an essential role as a structural component of animal cell membranes. The ubiquity of cholesterol in the environment has made it a reference biomarker for environmental pollution analysis and a common carbon source for different microorganisms, some of them being important pathogens such as Mycobacterium tuberculosis. This work revises the accumulated biochemical and genetic knowledge on the bacterial pathways that degrade or transform this molecule, given that the characterization of cholesterol metabolism would contribute not only to understand its role in tuberculosis but also to develop new biotechnological processes that use this and other related molecules as starting or target materials. © 2012 The Authors; Microbial Biotechnology © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Global prediction of continuous hydrocarbon accumulations in self-sourced reservoirs

USGS Publications Warehouse

Eoff, Jennifer D.

2012-01-01

This report was first presented as an abstract in poster format at the American Association of Petroleum Geologists (AAPG) 2012 Annual Convention and Exhibition, April 22-25, Long Beach, Calif., as Search and Discovery Article no. 90142. Shale resource plays occur in predictable tectonic settings within similar orders of magnitude of eustatic events. A conceptual model for predicting the presence of resource-quality shales is essential for evaluating components of continuous petroleum systems. Basin geometry often distinguishes self-sourced resource plays from conventional plays. Intracratonic or intrashelf foreland basins at active margins are the predominant depositional settings among those explored for the development of self-sourced continuous accumulations, whereas source rocks associated with conventional accumulations typically were deposited in rifted passive margin settings (or other cratonic environments). Generally, the former are associated with the assembly of supercontinents, and the latter often resulted during or subsequent to the breakup of landmasses. Spreading rates, climate, and eustasy are influenced by these global tectonic events, such that deposition of self-sourced reservoirs occurred during periods characterized by rapid plate reconfiguration, predominantly greenhouse climate conditions, and in areas adjacent to extensive carbonate sedimentation. Combined tectonic histories, eustatic curves, and paleogeographic reconstructions may be useful in global predictions of organic-rich shale accumulations suitable for continuous resource development. Accumulation of marine organic material is attributed to upwellings that enhance productivity and oxygen-minimum bottom waters that prevent destruction of organic matter. The accumulation of potential self-sourced resources can be attributed to slow sedimentation rates in rapidly subsiding (incipient, flexural) foreland basins, while flooding of adjacent carbonate platforms and other cratonic highs occurred. In contrast, deposition of this resource type on rifted passive margins was likely the result of reactivation of long-lived cratonic features or salt tectonic regimes that created semi-confined basins. Commonly, loading by thick sections of clastic material, following thermal relaxation after plate collision or rift phases, advances kerogen maturation. With few exceptions, North American self-sourced reservoirs appear to be associated with calcitic seas and predominantly greenhouse or transitional ("warm" to "cool") global climatic conditions. Significant changes to the global carbon budget may also be a contributing factor in the stratigraphic distribution of continuous resource plays, requiring additional evaluation.

Paleofacies of Eocene Lower Ngimbang Source Rocks in Cepu Area, East Java Basin based on Biomarkers and Carbon-13 Isotopes

NASA Astrophysics Data System (ADS)

Devi, Elok A.; Rachman, Faisal; Satyana, Awang H.; Fahrudin; Setyawan, Reddy

2018-02-01

The Eocene Lower Ngimbang carbonaceous shales are geochemically proven hydrocarbon source rocks in the East Java Basin. Sedimentary facies of source rock is important for the source evaluation that can be examined by using biomarkers and carbon-13 isotopes data. Furthermore, paleogeography of the source sedimentation can be reconstructed. The case study was conducted on rock samples of Lower Ngimbang from two exploration wells drilled in Cepu area, East Java Basin, Kujung-1 and Ngimbang-1 wells. The biomarker data include GC and GC-MS data of normal alkanes, isoprenoids, triterpanes, and steranes. Carbon-13 isotope data include saturate and aromatic fractions. Various crossplots of biomarker and carbon-13 isotope data of the Lower Ngimbang source samples from the two wells show that the source facies of Lower Ngimbang shales changed from transitional/deltaic setting at Kujung-1 well location to marginal marine setting at Ngimbang-1 well location. This reveals that the Eocene paleogeography of the Cepu area was composed of land area in the north and marine setting to the south. Biomarkers and carbon-13 isotopes are powerful data for reconstructing paleogeography and paleofacies. In the absence of fossils in some sedimentary facies, these geochemical data are good alternatives.

Investigating effectiveness of activated carbons of natural sources on various supercapacitors

NASA Astrophysics Data System (ADS)

Faisal, Md. Shahnewaz Sabit; Rahman, Muhammad M.; Asmatulu, Ramazan

2016-04-01

Activated carbon can be produced from natural sources, such as pistachio and acorn shells, which can be an inexpensive and sustainable sources of natural wastes for the energy storage devices, such as supercapacitors. The carbonaceous materials used in this study were carbonized at the temperatures of 700°C and 900°C after the stabilization process at 240°C for two hours. These shells showed approximately 60% carbon yield. Carbonized nutshells were chemically activated using1wt% potassium hydroxide (KOH). Activated carbon powders with polyvinylidene fluoride (PVdF) were used to construct carbon electrodes. A 1M of tetraethylammonium tetrafluoroborate (TEABF4) and propylene carbonate (PC) were used as electrolytes. Electrochemical techniques, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characterization of the supercapacitors. Scanning electron microscopy (SEM) was used to inspect the surface texture of the activated carbons. Activated pistachio shells carbonized at 700°C showed more porous surface texture than those carbonized at 900°C. Effects of the carbonization temperatures were studied for their electrochemical characteristics. The shells carbonized at 700°C showed better electrochemical characteristics compared to those carbonized at 900°C. The test results provided about 27,083 μF/g specific capacitance at a scan rate of 10mV/s. This study showed promising results for using these activated carbons produced from the natural wastes for supercapacitor applications.

CO2 mitigation potential of mineral carbonation with industrial alkalinity sources in the United States.

PubMed

Kirchofer, Abby; Becker, Austin; Brandt, Adam; Wilcox, Jennifer

2013-07-02

The availability of industrial alkalinity sources is investigated to determine their potential for the simultaneous capture and sequestration of CO2 from point-source emissions in the United States. Industrial alkalinity sources investigated include fly ash, cement kiln dust, and iron and steel slag. Their feasibility for mineral carbonation is determined by their relative abundance for CO2 reactivity and their proximity to point-source CO2 emissions. In addition, the available aggregate markets are investigated as possible sinks for mineral carbonation products. We show that in the U.S., industrial alkaline byproducts have the potential to mitigate approximately 7.6 Mt CO2/yr, of which 7.0 Mt CO2/yr are CO2 captured through mineral carbonation and 0.6 Mt CO2/yr are CO2 emissions avoided through reuse as synthetic aggregate (replacing sand and gravel). The emission reductions represent a small share (i.e., 0.1%) of total U.S. CO2 emissions; however, industrial byproducts may represent comparatively low-cost methods for the advancement of mineral carbonation technologies, which may be extended to more abundant yet expensive natural alkalinity sources.

Differentiation of lard, chicken fat, beef fat and mutton fat by GCMS and EA-IRMS techniques.

PubMed

Ahmad Nizar, Nina Naquiah; Nazrim Marikkar, Jalaldeen Mohamed; Hashim, Dzulkifly Mat

2013-01-01

A study was conducted to differentiate lard, chicken fat, beef fat and mutton fat using Gas Chromatography Mass Spectrometry (GC-MS) and Elemental Analyzer-Isotope Ratio Mass Spectrometry (EA-IRMS). The comparison of overall fatty acid data showed that lard and chicken fat share common characteristics by having palmitic, oleic and linoleic acid as major fatty acids while beef and mutton fats shared common characteristics by possessing palmitic, stearic and oleic acid as major fatty acids. The direct comparisons among the fatty acid data, therefore, may not be suitable for discrimination of different animal fats. When the fatty acid distributional data was subjected to Principle Component Analysis (PCA), it was demonstrated that stearic, oleic and linoleic acids as the most discriminating parameters in the clustering of animal fats into four subclasses. The bulk carbon analysis of animal fats using EA-IRMS showed that determination of the carbon isotope ratios (δ¹³C) would be a good indicator for discriminating lard, chicken fat, beef fat and mutton fat. This would lead to a faster and more efficient method to ascertain the source of origin of fats used in food products.

Diagnosis of potential stressors adversely affecting benthic ...

EPA Pesticide Factsheets

Greenwich Bay is an urbanized embayment of Narragansett Bay potentially impacted by multiple stressors. The present study identified the important stressors affecting Greenwich Bay benthic fauna. First, existing data and information were used to confirm that the waterbody was impaired. Second, the presence of source, stressor, and effect were established. Then linkages between source, stressor, and effect were developed. This allows identification of probable stressors adversely affecting the waterbody. Three pollutant categories were assessed: chemicals, nutrients, and suspended sediments. This weight of evidence approach indicated that Greenwich Bay was primarily impacted by eutrophication-related stressors. The sediments of Greenwich Bay were carbon enriched and low dissolved oxygen concentrations were commonly seen, especially in the western portions of Greenwich Bay. The benthic community was depauperate, as would be expected under oxygen stress. Although our analysis indicated that contaminant loads in Greenwich Bay were at concentrations where adverse effects might be expected, no toxicity was observed, as a result of high levels of organic carbon in these sediments reducing contaminant bioavailability. Our analysis also indicated that suspended sediment impacts were likely nonexistent for much of the Bay. This analysis demonstrates that the diagnostic procedure was useful to organize and assess the potential stressors impacting the ecological well-being

Assessment of self-organizing maps to analyze sole-carbon source utilization profiles.

PubMed

Leflaive, Joséphine; Céréghino, Régis; Danger, Michaël; Lacroix, Gérard; Ten-Hage, Loïc

2005-07-01

The use of community-level physiological profiles obtained with Biolog microplates is widely employed to consider the functional diversity of bacterial communities. Biolog produces a great amount of data which analysis has been the subject of many studies. In most cases, after some transformations, these data were investigated with classical multivariate analyses. Here we provided an alternative to this method, that is the use of an artificial intelligence technique, the Self-Organizing Maps (SOM, unsupervised neural network). We used data from a microcosm study of algae-associated bacterial communities placed in various nutritive conditions. Analyses were carried out on the net absorbances at two incubation times for each substrates and on the chemical guild categorization of the total bacterial activity. Compared to Principal Components Analysis and cluster analysis, SOM appeared as a valuable tool for community classification, and to establish clear relationships between clusters of bacterial communities and sole-carbon sources utilization. Specifically, SOM offered a clear bidimensional projection of a relatively large volume of data and were easier to interpret than plots commonly obtained with multivariate analyses. They would be recommended to pattern the temporal evolution of communities' functional diversity.

Glycerol metabolism and transport in yeast and fungi: established knowledge and ambiguities.

PubMed

Klein, Mathias; Swinnen, Steve; Thevelein, Johan M; Nevoigt, Elke

2017-03-01

There is huge variability among yeasts with regard to their efficiency in utilizing glycerol as the sole source of carbon and energy. Certain species show growth rates with glycerol comparable to those reached with glucose as carbon source; others are virtually unable to utilize glycerol, especially in synthetic medium. Most of our current knowledge regarding glycerol uptake and catabolic pathways has been gained from studying laboratory strains of the model yeast Saccharomyces cerevisiae. The growth of these strains on glycerol is dependent on the presence of medium supplements such as amino acids and nucleobases. In contrast, there is only fragmentary knowledge about S. cerevisiae isolates able to grow in synthetic glycerol medium without such supplements as well as about growth of non-Saccharomyces yeast species on glycerol. Thus, more research is required to understand why certain strains and species show superior growth performance on glycerol compared with common S. cerevisiae laboratory strains. This mini-review summarizes what is known so far about the gene products and pathways involved in glycerol metabolism and transport in yeast and fungi as well as the regulation of these processes. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Bifidobacteria exhibit social behavior through carbohydrate resource sharing in the gut

PubMed Central

Milani, Christian; Andrea Lugli, Gabriele; Duranti, Sabrina; Turroni, Francesca; Mancabelli, Leonardo; Ferrario, Chiara; Mangifesta, Marta; Hevia, Arancha; Viappiani, Alice; Scholz, Matthias; Arioli, Stefania; Sanchez, Borja; Lane, Jonathan; Ward, Doyle V.; Hickey, Rita; Mora, Diego; Segata, Nicola; Margolles, Abelardo; van Sinderen, Douwe; Ventura, Marco

2015-01-01

Bifidobacteria are common and frequently dominant members of the gut microbiota of many animals, including mammals and insects. Carbohydrates are considered key carbon sources for the gut microbiota, imposing strong selective pressure on the complex microbial consortium of the gut. Despite its importance, the genetic traits that facilitate carbohydrate utilization by gut microbiota members are still poorly characterized. Here, genome analyses of 47 representative Bifidobacterium (sub)species revealed the genes predicted to be required for the degradation and internalization of a wide range of carbohydrates, outnumbering those found in many other gut microbiota members. The glycan-degrading abilities of bifidobacteria are believed to reflect available carbon sources in the mammalian gut. Furthermore, transcriptome profiling of bifidobacterial genomes supported the involvement of various chromosomal loci in glycan metabolism. The widespread occurrence of bifidobacterial saccharolytic features is in line with metagenomic and metatranscriptomic datasets obtained from human adult/infant faecal samples, thereby supporting the notion that bifidobacteria expand the human glycobiome. This study also underscores the hypothesis of saccharidic resource sharing among bifidobacteria through species-specific metabolic specialization and cross feeding, thereby forging trophic relationships between members of the gut microbiota. PMID:26506949

Evaluating measurements of carbon dioxide emissions using a precision source--A natural gas burner.

PubMed

Bryant, Rodney; Bundy, Matthew; Zong, Ruowen

2015-07-01

A natural gas burner has been used as a precise and accurate source for generating large quantities of carbon dioxide (CO2) to evaluate emissions measurements at near-industrial scale. Two methods for determining carbon dioxide emissions from stationary sources are considered here: predicting emissions based on fuel consumption measurements-predicted emissions measurements, and direct measurement of emissions quantities in the flue gas-direct emissions measurements. Uncertainty for the predicted emissions measurement was estimated at less than 1%. Uncertainty estimates for the direct emissions measurement of carbon dioxide were on the order of ±4%. The relative difference between the direct emissions measurements and the predicted emissions measurements was within the range of the measurement uncertainty, therefore demonstrating good agreement. The study demonstrates how independent methods are used to validate source emissions measurements, while also demonstrating how a fire research facility can be used as a precision test-bed to evaluate and improve carbon dioxide emissions measurements from stationary sources. Fossil-fuel-consuming stationary sources such as electric power plants and industrial facilities account for more than half of the CO2 emissions in the United States. Therefore, accurate emissions measurements from these sources are critical for evaluating efforts to reduce greenhouse gas emissions. This study demonstrates how a surrogate for a stationary source, a fire research facility, can be used to evaluate the accuracy of measurements of CO2 emissions.

Carbon-14 in methane sources and in atmospheric methane - The contribution from fossil carbon

NASA Technical Reports Server (NTRS)

Wahlen, M.; Tanaka, N.; Henry, R.; Deck, B.; Zeglen, J.

1989-01-01

Measurements of carbon-14 in small samples of methane from major biogenic sources, from biomass burning, and in clean air samples from both the Northern and Southern hemispheres reveal that methane from ruminants contains contemporary carbon, whereas that from wetlands, peat bogs, rice fields, and tundra, is somewhat depleted in carbon-14. Atmospheric (C-14)H4 seems to have increased from 1986 to 1987, and levels at the end of 1987 were 123.3 + or - 0.8 percent modern carbon in the Northern Hemisphere and 120.0 + or - 0.7 percent modern carbon in the Southern Hemisphere.

Carbon source/sink function of a subtropical, eutrophic lake determined from an overall mass balance and a gas exchange and carbon burial balance.

PubMed

Yang, Hong; Xing, Yangping; Xie, Ping; Ni, Leyi; Rong, Kewen

2008-02-01

Although studies on carbon burial in lake sediments have shown that lakes are disproportionately important carbon sinks, many studies on gaseous carbon exchange across the water-air interface have demonstrated that lakes are supersaturated with CO(2) and CH(4) causing a net release of CO(2) and CH(4) to the atmosphere. In order to more accurately estimate the net carbon source/sink function of lake ecosystems, a more comprehensive carbon budget is needed, especially for gaseous carbon exchange across the water-air interface. Using two methods, overall mass balance and gas exchange and carbon burial balance, we assessed the carbon source/sink function of Lake Donghu, a subtropical, eutrophic lake, from April 2003 to March 2004. With the overall mass balance calculations, total carbon input was 14 905 t, total carbon output was 4950 t, and net carbon budget was +9955 t, suggesting that Lake Donghu was a great carbon sink. For the gas exchange and carbon burial balance, gaseous carbon (CO(2) and CH(4)) emission across the water-air interface totaled 752 t while carbon burial in the lake sediment was 9477 t. The ratio of carbon emission into the atmosphere to carbon burial into the sediment was only 0.08. This low ratio indicates that Lake Donghu is a great carbon sink. Results showed good agreement between the two methods with both showing Lake Donghu to be a great carbon sink. This results from the high primary production of Lake Donghu, substantive allochthonous carbon inputs and intensive anthropogenic activity. Gaseous carbon emission accounted for about 15% of the total carbon output, indicating that the total output would be underestimated without including gaseous carbon exchange.

40 CFR 458.46 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Pretreatment standards for new sources. 458.46 Section 458.46 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp...

40 CFR 458.46 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Pretreatment standards for new sources. 458.46 Section 458.46 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp...

A novel growth-promoting microbe, Methylobacterium funariae sp. nov., isolated from the leaf surface of a common moss.

PubMed

Schauer, S; Kutschera, U

2011-04-01

Land plants (embryophytes) evolved in the presence of prokaryotic microbes. As a result, numerous mutually beneficial associations (symbioses) developed that can be analyzed using a variety of methods. Here we describe the isolation and characterization of a new pink-pigmented facultatively methylotrophic symbiotic bacterium of the genus Methylobacterium (laboratory strain F3.2) that was isolated from the gametophytic phylloids of the common cord moss Funaria hygrometrica Hedw. Plantlets were collected in the field and analyzed in the laboratory. Colonies of methylobacteria were obtained by the agar-impression-method. Based on its unique phenotype (the bacterial cells are characterized by fimbriae-like appendages), a comparative 16S rRNA gene (DNA) sequence analysis, and an average DNA-DNA hybridization value of 8,4 %, compared with its most closely related sister taxon, this isolate is described as a new species, Methylobacterium funariae sp. nov. (type strain F3.2). This new epiphytic bacterium inhabits the leaf surface of "primitive" land plants such as mosses and interacts with its host organism via the secretion of phytohormones (cytokinines, auxins). These external signals are perceived by the plant cells that divide and grow more rapidly than in the absence of their prokaryotic phytosymbionts. We suggest that M. funariae sp. nov. uses methanol emitted from the stomatal pores as principal carbon source for cell metabolism. However, our novel data indicate that, in this unique symbiotic plant-microbe interaction, the uptake of amino acids leached from the surface of the epidermal cells of the green host organism may be of importance as microbial carbon- and nitrogen-source.

Different carbon sources affect PCB accumulation by marine bivalves.

PubMed

Laitano, M V; Silva Barni, M F; Costa, P G; Cledón, M; Fillmann, G; Miglioranza, K S B; Panarello, H O

2016-02-01

Pampean creeks were evaluated in the present study as potential land-based sources of PCB marine contamination. Different carbon and nitrogen sources from such creeks were analysed as boosters of PCB bioaccumulation by the filter feeder bivalve Brachidontes rodriguezii and grazer limpet Siphonaria lessoni. Carbon of different source than marine and anthropogenic nitrogen assimilated by organisms were estimated through their C and N isotopic composition. PCB concentration in surface sediments and mollusc samples ranged from 2.68 to 6.46 ng g(-1) (wet weight) and from 1074 to 4583 ng g(-1) lipid, respectively, reflecting a punctual source of PCB contamination related to a landfill area. Thus, despite the low flow of creeks, they should not be underestimated as contamination vectors to the marine environment. On the other hand, mussels PCB bioaccumulation was related with the carbon source uptake which highlights the importance to consider this factor when studying PCB distribution in organisms of coastal systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

NASA Astrophysics Data System (ADS)

Keskitalo, Kirsi; Tesi, Tommaso; Bröder, Lisa; Andersson, August; Pearce, Christof; Sköld, Martin; Semiletov, Igor P.; Dudarev, Oleg V.; Gustafsson, Örjan

2017-09-01

Thawing of permafrost carbon (PF-C) due to climate warming can remobilise considerable amounts of terrestrial carbon from its long-term storage to the marine environment. PF-C can be then be buried in sediments or remineralised to CO2 with implications for the carbon-climate feedback. Studying historical sediment records during past natural climate changes can help us to understand the response of permafrost to current climate warming. In this study, two sediment cores collected from the East Siberian Sea were used to study terrestrial organic carbon sources, composition and degradation during the past ˜ 9500 cal yrs BP. CuO-derived lignin and cutin products (i.e., compounds solely biosynthesised in terrestrial plants) combined with δ13C suggest that there was a higher input of terrestrial organic carbon to the East Siberian Sea between ˜ 9500 and 8200 cal yrs BP than in all later periods. This high input was likely caused by marine transgression and permafrost destabilisation in the early Holocene climatic optimum. Based on source apportionment modelling using dual-carbon isotope (Δ14C, δ13C) data, coastal erosion releasing old Pleistocene permafrost carbon was identified as a significant source of organic matter translocated to the East Siberian Sea during the Holocene.

The Crc protein inhibits the production of polyhydroxyalkanoates in Pseudomonas putida under balanced carbon/nitrogen growth conditions.

PubMed

La Rosa, Ruggero; de la Peña, Fernando; Prieto, María Axiliadora; Rojo, Fernando

2014-01-01

Pseudomonas putida synthesizes polyhydroxyalkanoates (PHAs) as storage compounds. PHA synthesis is more active when the carbon source is in excess and the nitrogen source is limiting, but can also occur at a lower rate under balanced carbon/nitrogen ratios. This work shows that PHA synthesis is controlled by the Crc global regulator, a protein that optimizes carbon metabolism by inhibiting the expression of genes involved in the use of non-preferred carbon sources. Crc acts post-transcriptionally. The mRNAs of target genes contain characteristic catabolite activity (CA) motifs near the ribosome binding site. Sequences resembling CA motifs can be predicted for the phaC1 gene, which codes for a PHA polymerase, and for phaI and phaF, which encode proteins associated to PHA granules. Our results show that Crc inhibits the translation of phaC1 mRNA, but not that of phaI or phaF, reducing the amount of PHA accumulated in the cell. Crc inhibited PHA synthesis during exponential growth in media containing a balanced carbon/nitrogen ratio. No inhibition was seen when the carbon/nitrogen ratio was imbalanced. This extends the role of Crc beyond that of controlling the hierarchical utilization of carbon sources and provides a link between PHA synthesis and the global regulatory networks controlling carbon flow. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Experimental determination of dissolved CO2 content in nominally anhydrous andesitic melts at graphite/diamond saturation - Remobilization of deeply subducted reduced carbon via partial melts of MORB-like eclogite

NASA Astrophysics Data System (ADS)

Eguchi, J.; Dasgupta, R.

2015-12-01

Experimental phase relations of carbonated lithologies [1] and geochemistry of deep diamonds [2] suggest that deep recycling of carbon has likely been efficient for a significant portion of Earth's history. Both carbonates and organic carbon subduct into the mantle, but with gradual decrease of fO2 with depth [3] most carbon in deep mantle rocks including eclogite could be diamond/graphite [4]. Previous studies investigated the transfer of CO2 from subducted eclogite to the ambient mantle by partial melting in the presence of carbonates, i.e., by generation of carbonate-rich melts [5]. However, the transfer of carbon from subducted eclogite to the mantle can also happen, perhaps more commonly, by extraction of silicate partial melt in the presence of reduced carbon; yet, CO2 solubility in eclogite-derived andesitic melt at graphite/diamond saturation remains unconstrained. CO2content of eclogite melts is also critical as geochemistry of many ocean island basalts suggest the presence of C and eclogite in their source regions [6]. In the present study we determine CO2 concentration in a model andesitic melt [7] at graphite/diamond saturation at conditions relevant for partial melting of eclogite in the convecting upper mantle. Piston cylinder and multi anvil experiments were conducted at 1-6 GPa and 1375-1550 °C using Pt/Gr double capsules. Oxygen fugacity was monitored with Pt-Fe sensors in the starting mix. Completed experiments at 1-3 GPa show that CO2 concentration increases with increasing P, T, and fO2 up to ~0.3 wt%. Results were used to develop empirical and thermodynamic models to predict CO2 concentration in partial melts of graphite saturated eclogite. This allowed us to quantify the extent to which CO2 can mobilize from eclogitic heterogeneities at graphite/diamond saturated conditions. With estimates of eclogite contribution to erupted basaltic lavas, the models developed here allow us to put constraints on the flux of CO2 to mantle source regions coming from subducted crust and investigate the possible role this process may play in the deep carbon cycle. [1] Dasgupta (2013) RiMG. [2] Shirey, et al. (2013) RiMG. [3] Frost & McCammon (2008) Ann Rev Earth Plan Sci. [4] Stagno, et al. (2015) CMP. [5] Kiseeva, et al. (2012) JPet. [6] Mallik & Dasgupta (2014) G3. [7] Spandler, et al. (2008) JPet.

[Harvest of the carbon source in wastewater by the adsorption and desorption of activated sludge].

PubMed

Liu, Hong-Bo; Wen, Xiang-Hua; Zhao, Fang; Mei, Yi-Jun

2011-04-01

The carbon source in municipal wastewater was adsorbed by activated sludge and then harvested through the hydrolysis of activated sludge. Results indicated that activated sludge had high absorbing ability towards organic carbon and phosphorus under continuous operation mode, and the average COD and TP absorption rate reached as high as 63% and 76%, respectively. Moreover, about 50% of the soluble carbon source was outside of the sludge cell and could be released under mild hydrolysis condition. Whereas the absorbed amount of nitrogen was relatively low, and the removal rate of ammonia was only 13% . Furthermore, the releases of organic carbon, nitrogen and phosphorus from the sludge absorbing pollutants in the wastewater were studied. By comparing different hydrolysis conditions of normal (pH 7.5, 20 degrees C), heating (pH 7.5, 60 degrees C) and the alkaline heating (pH 11, 60 degrees C), the last one presented the optimum hydrolysis efficiency. Under which, the release rate of COD could reach 320 mg/g after 24 hours, whereas nitrogen and phosphorus just obtained low release rates of 18 mg/g and 2 mg/g, respectively. Results indicate that the carbon source in wastewater could be harvested by the adsorption and desorption of activated sludge, and the concentrations of nitrogen and phosphorus are low and would not influence the reuse of the harvested carbon source.

Carbon isotope fractionation during microbial methane oxidation

NASA Astrophysics Data System (ADS)

Barker, James F.; Fritz, Peter

1981-09-01

Methane, a common trace constituent of groundwaters, occasionally makes up more than 20% of the total carbon in groundwaters1,2. In aerobic environments CH4-rich waters can enable microbial food chain supporting a mixed culture of bacteria with methane oxidation as the primary energy source to develop3. Such processes may influence the isotopic composition of the residual methane and because 13C/12C analyses have been used to characterize the genesis of methanes found in different environments, an understanding of the magnitude of such effects is necessary. In addition, carbon dioxide produced by the methane-utilizing bacteria can be added to the inorganic carbon pool of affected groundwaters. We found carbon dioxide experimentally produced by methane-utilizing bacteria to be enriched in 12C by 5.0-29.6‰, relative to the residual methane. Where methane-bearing groundwaters discharged into aerobic environments microbial methane oxidation occurred, with the residual methane becoming progressively enriched in 13C. Various models have been proposed to explain the 13C/12C and 14C content of the dissolved inorganic carbon (DIC) of groundwaters in terms of additions or losses during flow in the subsurface4,5. The knowledge of both stable carbon isotope ratios in various pools and the magnitude of carbon isotope fractionation during various processes allows geochemists to use the 13C/12C ratio of the DIC along with water chemistry to estimate corrected 14C groundwater ages4,5. We show here that a knowledge of the carbon isotope fractionation between CH4 and CO2 during microbial methane-utilization could modify such models for application to groundwaters affected by microbial methane oxidation.

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.

Synthesis and applications of carbon nanomaterials for energy generation and storage.

PubMed

Notarianni, Marco; Liu, Jinzhang; Vernon, Kristy; Motta, Nunzio

2016-01-01

The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Over the last 20 years, carbon, one of the most abundant materials found on earth, and its allotrope forms such as fullerenes, carbon nanotubes and graphene have been proposed as sources of energy generation and storage because of their extraordinary properties and ease of production. Various approaches for the synthesis and incorporation of carbon nanomaterials in organic photovoltaics and supercapacitors have been reviewed and discussed in this work, highlighting their benefits as compared to other materials commonly used in these devices. The use of fullerenes, carbon nanotubes and graphene in organic photovoltaics and supercapacitors is described in detail, explaining how their remarkable properties can enhance the efficiency of solar cells and energy storage in supercapacitors. Fullerenes, carbon nanotubes and graphene have all been included in solar cells with interesting results, although a number of problems are still to be overcome in order to achieve high efficiency and stability. However, the flexibility and the low cost of these materials provide the opportunity for many applications such as wearable and disposable electronics or mobile charging. The application of carbon nanotubes and graphene to supercapacitors is also discussed and reviewed in this work. Carbon nanotubes, in combination with graphene, can create a more porous film with extraordinary capacitive performance, paving the way to many practical applications from mobile phones to electric cars. In conclusion, we show that carbon nanomaterials, developed by inexpensive synthesis and process methods such as printing and roll-to-roll techniques, are ideal for the development of flexible devices for energy generation and storage - the key to the portable electronics of the future.

Synthesis and applications of carbon nanomaterials for energy generation and storage

PubMed Central

Notarianni, Marco; Liu, Jinzhang; Vernon, Kristy

2016-01-01

Summary The world is facing an energy crisis due to exponential population growth and limited availability of fossil fuels. Over the last 20 years, carbon, one of the most abundant materials found on earth, and its allotrope forms such as fullerenes, carbon nanotubes and graphene have been proposed as sources of energy generation and storage because of their extraordinary properties and ease of production. Various approaches for the synthesis and incorporation of carbon nanomaterials in organic photovoltaics and supercapacitors have been reviewed and discussed in this work, highlighting their benefits as compared to other materials commonly used in these devices. The use of fullerenes, carbon nanotubes and graphene in organic photovoltaics and supercapacitors is described in detail, explaining how their remarkable properties can enhance the efficiency of solar cells and energy storage in supercapacitors. Fullerenes, carbon nanotubes and graphene have all been included in solar cells with interesting results, although a number of problems are still to be overcome in order to achieve high efficiency and stability. However, the flexibility and the low cost of these materials provide the opportunity for many applications such as wearable and disposable electronics or mobile charging. The application of carbon nanotubes and graphene to supercapacitors is also discussed and reviewed in this work. Carbon nanotubes, in combination with graphene, can create a more porous film with extraordinary capacitive performance, paving the way to many practical applications from mobile phones to electric cars. In conclusion, we show that carbon nanomaterials, developed by inexpensive synthesis and process methods such as printing and roll-to-roll techniques, are ideal for the development of flexible devices for energy generation and storage – the key to the portable electronics of the future. PMID:26925363

Quantifying the potential for low-level transport of black carbon emissions from cropland burning in Russia to the snow-covered Arctic.

NASA Astrophysics Data System (ADS)

Hall, Joanne V.; Loboda, Tatiana V.

2017-12-01

Short-lived aerosols and pollutants transported from northern mid-latitudes have amplified the short term warming in the Arctic region. Among those black carbon is recognized as the second most important human emission in regards to climate forcing, behind carbon dioxide, with a total climate forcing of +1.1Wm-2. Studies have suggested that cropland burning may be a large contributor to the black carbon emissions which are directly deposited on the snow in the Arctic. However, commonly applied atmospheric transport models rely on estimates of black carbon emissions from cropland burning which are known to be highly inaccurate in both the amount and the timing of release. Instead, this study quantifies the potential for the deposition of hypothetical black carbon emissions from known cropland burning in Russia, identified by the Moderate Resolution Imaging Spectroradiometer (MODIS) active fire detections, through low-level transport to the snow in the Arctic using wind vectors from the European Centre for Medium-Range Weather Forecasts’ ERA-Interim Reanalysis product. Our results confirm that Russian cropland burning is a potentially significant source of black carbon deposition on the Arctic snow in the spring despite the low injection heights associated with cropland burning. Approximately 10% of the observed spring (March - May) cropland active fires (7% annual) likely contribute to black carbon deposition on the Arctic snow from as far south as at least 40°N. Furthermore, our results show that potential spring black carbon emissions from cropland burning in Russia can be deposited beyond 80°N, however, the majority ( 90% - depending on injection height) of all potential spring deposition occurs below 75°N.

Bounding the Role of Black Carbon in the Climate System: A Scientific Assessment

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

Bond, Tami C.; Doherty, Sarah J.; Fahey, D. W.

2013-06-06

Black carbon aerosol plays a unique and important role in Earth’s climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. Predominant sources are combustion related; namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr-1 in the year 2000 with an uncertainty range of 2000 to 29000. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that ismore » quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption, influence on liquid, mixed-phase, and ice clouds, and deposition on snow and ice. These effects are calculated with models, but when possible, they are evaluated with both microphysical measurements and field observations. Global atmospheric absorption attributable to black carbon is too low in many models, and should be increased by about about 60%. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of black carbon is +0.43 W m-2 with 90% uncertainty bounds of (+0.17, +0.68) W m-2. Total direct forcing by all black carbon sources in the present day is estimated as +0.49 (+0.20, +0.76) W m-2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings and their rapid responses and feedbacks. The best estimate of industrial-era (1750 to 2005) climate forcing of black carbon through all forcing mechanisms is +0.77 W m-2 with 90% uncertainty bounds of +-0.06 to +1.53 W m-2. Thus, there is a 96% probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. With a value of +0.77 W m-2, black carbon is likely the second most important individual climate-forcing agent in the industrial era, following carbon dioxide. Sources that emit black carbon also emit other short- lived species that may either cool or warm climate. Climate forcings from co-emitted species are estimated and used in the framework described herein. When the principal effects of co- emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy-related sources (fossil-fuel and biofuel) have a net climate forcing of +0.004 (-0.62 to +0.57) W m-2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial-era climate forcing by all black- carbon-rich sources becomes slightly negative (-0.08 W m-2 with 90% uncertainty bounds of -1.23 to +0.81 W m-2). The uncertainties in net climate forcing from black-carbon-rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co-emitted organic carbon. In prioritizing potential black-carbon mitigation actions, non-science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near-term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black-carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.« less

Activated sludge is a potential source for production of biodegradable plastics from wastewater.

PubMed

Khardenavis, A; Guha, P K; Kumar, M S; Mudliar, S N; Chakrabarti, T

2005-05-01

Increased utilization of synthetic plastics caused severe environmental pollution due to their non-biodegradable nature. In the search for environmentally friendly materials to substitute for conventional plastics, different biodegradable plastics have been developed by microbial fermentations. However, limitations of these materials still exist due to high cost. This study aims at minimization of cost for the production of biodegradable plastics P(3HB) and minimization of environmental pollution. The waste biological sludge generated at wastewater treatment plants is used for the production of P(3HB) and wastewater is used as carbon source. Activated sludge was induced by controlling the carbon: nitrogen ratio to accumulate storage polymer. Initially polymer accumulation was studied by using different carbon and nitrogen sources. Maximum accumulation of polymer was observed with carbon source acetic acid and diammonium hydrogen phosphate (DAHP) as nitrogen source. Further studies were carried out to optimize the carbon: nitrogen ratios using acetic acid and DAHP. A maximum of 65.84% (w/w) P(3HB) production was obtained at C/N ratio of 50 within 96 hours of incubation.

A time resolved metabolomics study: the influence of different carbon sources during growth and starvation of Bacillus subtilis.

PubMed

Meyer, Hanna; Weidmann, Hendrikje; Mäder, Ulrike; Hecker, Michael; Völker, Uwe; Lalk, Michael

2014-07-01

In its natural environment, the soil, the Gram-positive model bacterium Bacillus subtilis frequently encounters nutrient limitation and other stress factors. Efficient adaptation mechanisms are necessary to cope with this wide range of environmental challenges. The ability to utilize diverse carbon sources represents a key adaptation process that allows B. subtilis to thrive in its natural habitat. To gain a comprehensive insight into the metabolism of B. subtilis, global metabolite analyses were performed during growth with glucose alone or glucose with either malate, fumarate or citrate as carbon/energy sources. Furthermore, to achieve a comprehensive coverage of a wide range of chemically different metabolites, complementary GC-MS, LC-MS and (1)H-NMR analyses were applied. This study reveals that the availability of different carbon sources results in different extracellular metabolite profiles whereas a regulated intracellular metabolite equilibrium was observed. In addition, the typical energy-starvation induced activation of the general stress sigma factor σ(B) was only observed upon entry into the stationary phase with glucose or glucose and malate as carbon sources.

Measurements of Carbon Dioxide, Methane, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

NASA Astrophysics Data System (ADS)

Yasuhara, Scott; Forgeron, Jeff; Rella, Chris; Franz, Patrick; Jacobson, Gloria; Chiao, Sen; Saad, Nabil

2013-04-01

The ability to quantify sources and sinks of carbon dioxide and methane on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to 'bottom-up' predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has proven to be effective at continental scales, becomes challenging to implement at urban scales, due to poorly understood atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, green spaces) and time (rush hours, factory shifts and shutdowns, and diurnal and seasonal variation in residential energy use). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal- resolution greenhouse gas measurements made by multiple Picarro-CRDS analyzers in Silicon Valley in California. Real-time carbon dioxide data from a 20-month period are combined with real-time carbon monoxide, methane, and acetylene to partition the observed carbon dioxide concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. Real-time wind rose data are also combined with real-time methane data to help identify the direction of local emissions of methane. High resolution WRF models are also included to better understand the dynamics of the boundary layer. The ratio between carbon dioxide and carbon monoxide is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid but frequent shifts in the balance between different carbon dioxide sources. Additional information is given by acetylene, a fossil fuel combustion tracer that provides complimentary information to carbon monoxide. In spring and summer, the combined signal of the urban center and the surrounding biosphere and urban green space is explored. These methods show great promise for identifying, quantifying, and partitioning urban-ecological (carbon) emissions.

Comparative Spectra of Oxygen-Rich Versus Carbon-Rich Circumstellar Shells: VY Canis Majoris and IRC(plus)10216 at 215-285 GHz

NASA Technical Reports Server (NTRS)

Tenebaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

2010-01-01

A sensitive (1sigma rms at 1 MHz resolution approx.3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO, and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO(+). Sulfur plays an important role in VY CMa, but saturated/ unsaturated carbon dominates the molecular content of IRC +102.16, producing CH2NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

Comparative Spectra of Oxygen-rich Versus Carbon-rich Circumstellar Shells: VY Canis Majoris and IRC +10216 at 215-285 GHz

NASA Astrophysics Data System (ADS)

Tenenbaum, E. D.; Dodd, J. L.; Milam, S. N.; Woolf, N. J.; Ziurys, L. M.

2010-09-01

A sensitive (1σ rms at 1 MHz resolution ~3 mK) 1 mm spectral line survey (214.5-285.5 GHz) of VY Canis Majoris (VY CMa) and IRC +10216 has been conducted to compare the chemistries of oxygen- and carbon-rich circumstellar envelopes. This study was carried out using the Submillimeter Telescope of the Arizona Radio Observatory with a new Atacama Large Millimeter Array type receiver. This survey is the first to chemically characterize an O-rich circumstellar shell at millimeter wavelengths. In VY CMa, 128 emission features were detected arising from 18 different molecules; and in IRC +10216, 720 lines were observed, assigned to 32 different species. The 1 mm spectrum of VY CMa is dominated by SO2 and SiS; in IRC +10216, C4H and SiC2 are the most recurrent species. Ten molecules were common to both sources: CO, SiS, SiO, CS, CN, HCN, HNC, NaCl, PN, and HCO+. Sulfur plays an important role in VY CMa, but saturated/unsaturated carbon dominates the molecular content of IRC +10216, producing CH2NH, for example. Although the molecular complexity of IRC +10216 is greater, VY CMa supports a unique "inorganic" chemistry leading to the oxides PO, AlO, and AlOH. Only diatomic and triatomic compounds were observed in VY CMa, while species with four or more atoms are common in IRC +10216, reflecting carbon's ability to form multiple strong bonds, unlike oxygen. In VY CMa, a new water maser (v 2 = 2) has been found, as well as vibrationally excited NaCl. Toward IRC +10216, vibrationally excited CCH was detected for the first time.

Radiocarbon dating, chronologic framework, and changes in accumulation rates of holocene estuarine sediments from Chesapeake Bay

USGS Publications Warehouse

Colman, Steven M.; Baucom, P.C.; Bratton, J.F.; Cronin, T. M.; McGeehin, J.P.; Willard, D.; Zimmerman, A.R.; Vogt, P.R.

2002-01-01

Rapidly accumulating Holocene sediments in estuaries commonly are difficult to sample and date. In Chesapeake Bay, we obtained sediment cores as much as 20 m in length and used numerous radiocarbon ages measured by accelarator mass spectrometry methods to provide the first detailed chronologies of Holocene sediment accumulation in the bay. Carbon in these sediments is a complex mixture of materials from a variety of sources. Analyses of different components of the sediments show that total organic carbon ages are largely unreliable, because much of the carbon (including coal) has been transported to the bay from upstream sources and is older than sediments in which it was deposited. Mollusk shells (clams, oysters) and foraminifera appear to give reliable results, although reworking and burrowing are potential problems. Analyses of museum specimens collected alive before atmospheric nuclear testing suggest that the standard reservoir correction for marine samples is appropriate for middle to lower Chesapeake Bay. The biogenic carbonate radiocarbon ages are compatible with 210 Pb and 137 Cs data and pollen stratigraphy from the same sites. Post-settlement changes in sediment transport and accumulation is an important environmental issue in many estuaries, including the Chesapeake. Our data show that large variations in sediment mass accumulation rates occur among sites. At shallow water sites, local factors seem to control changes in accumulation rates with time. Our two relatively deep-water sites in the axial channel of the bay have different long-term average accumulation rates, but the history of sediment accumulation at these sites appears to reflect overall conditions in the bay. Mass accumulation rates at the two deep-water sites rapidly increased by about fourfold coincident with widespread land clearance for agriculture in the Chesapeake watershed.

Budget of coral-derived organic carbon in a fringing coral reef of the Gulf of Aqaba, Red Sea

NASA Astrophysics Data System (ADS)

Naumann, Malik S.; Richter, Claudio; Mott, Claudius; el-Zibdah, Mohammad; Manasrah, Riyad; Wild, Christian

2012-12-01

The continuous release of organic C-rich material by reef-building corals can contribute substantially to biogeochemical processes and concomitant rapid nutrient recycling in coral reef ecosystems. However, our current understanding of these processes is limited to platform reefs exhibiting a high degree of ecosystem closure compared to the globally most common fringing reef type. This study carried out in the northern Gulf of Aqaba (Red Sea) presents the first quantitative budget for coral-derived organic carbon (COC) in a fringing reef and highlights the importance of local hydrodynamics. Diel reef-wide COC release amounted to 1.1 ± 0.2 kmol total organic carbon (TOC) representing 1-3% of gross benthic primary production. Most COC (73%) was released as particulate organic C (POC), the bulk of which (34-63%) rapidly settled as mucus string aggregates accounting for approximately 28% of total POC sedimentation. Sedimentation of mucus strings, but also dilution of suspended and dissolved COC in reef waters retained 82% of diel COC release in the fringing reef, providing a potentially important organic source for a COC-based food web. Pelagic COC degradation represented 0.1-1.6% of pelagic microbial respiration recycling 32% of diel retained COC. Benthic COC degradation contributed substantially (29-47%) to reef-wide microbial respiration in reef sands, including 20-38% by mucus string POC, and consumed approximately 52% of all retained COC. These findings point out the importance of COC as a C carrier for different reef types. COC may further represent a source of organic carbon for faunal communities colonising reef framework cavities complementing the efficient retention and recycling of COC within fringing reef environments.

Trace elements and organic contaminants in stream sediments from the Red River of the North Basin

USGS Publications Warehouse

Brigham, M.E.; Tornes, L.H.

1996-01-01

To assess the presence and distribution of a variety of hydro-phobic chemicals in streams in the Red River of the North Basin, bottom sediments were analyzed for trace elements, organochlorines, and polycyclic aromatic hydrocarbons (PAHs). Glaciolacustrine clays and carbonate minerals are common in fine sediments of the region, and can help explain the distribution of many elements. Aluminum (Al), an indicator of glaciolacustrine clay minerals, correlates strongly (r>0.75, p<0.05) with Cr, Co, Fe, La, Li, K, Sc, and Ti; and moderately (0.55

Linking Carbon Flux Dynamics and Soil Structure in Dryland Soils

NASA Astrophysics Data System (ADS)

DeCarlo, K. F.; Caylor, K. K.

2016-12-01

Biological sources in the form of microbes and plants play a fundamental role in determining the magnitude of carbon flux. However, the geophysical structure of the soil (which the carbon must pass through before entering the atmosphere) often serves as a constraining entity, which has the potential to serve as instigators or mitigators of those carbon and hydrologic flux processes. We characterized soil carbon dynamics in three dryland soil systems: bioturbated soils, biocompacted soils, and undisturbed soils. Carbon fluxes were characterized using a closed-system respiration chamber, with CO2 concentration differences measured using an infrared gas analyzer (IRGA). Structure of the soil systems, with a focus on the macro-crack structure, were characterized using a combined resin-casting/X-ray imaging technique. Results show fundamental differences in carbon dynamics between the different soil systems/structures: control soils have gaussian distributions of carbon flux that decrease with progressive drying of the soil, while biocompacted soils exhibit exponentially distributed fluxes that do not regularly decrease with increased drying of the soil. Bioturbated soils also exhibit an exponential distribution of carbon flux, though at a much higher magnitude. These differences are evaluated in the context of the underlying soil structure: while the control soils exhibit a shallow and narrow crack structure, the biocompacted soils exhibit a "systematic" crack network with moderate cracking intensity and large depth. The deep crack networks of the biocompacted soils may serve to physically enhance an otherwise weak source of carbon via advection and/or convection, inducing fluxes that are equal or greater than an otherwise carbon-rich soil. The bioturbated soils exhibit a "surficial" crack network that is shallow but extensive, but additionally have deep holes known to convectively vent carbon, which may explain their periodically large carbon fluxes. Our results suggest that variability in soil structure, as well as carbon source, plays a fundamental role in carbon flux dynamics, and the importance of evaluating biological carbon source and geophysical soil structure in a dryland environment.

Pectin, Hemicellulose, or Lignin? Impact of the Biowaste Source on the Performance of Hard Carbons for Sodium-Ion Batteries.

PubMed

Dou, Xinwei; Hasa, Ivana; Hekmatfar, Maral; Diemant, Thomas; Behm, R Jürgen; Buchholz, Daniel; Passerini, Stefano

2017-06-22

Hard carbons are currently the most widely used negative electrode materials in Na-ion batteries. This is due to their promising electrochemical performance with capacities of 200-300 mAh g -1 and stable long-term cycling. However, an abundant and cheap carbon source is necessary in order to comply with the low-cost philosophy of Na-ion technology. Many biological or waste materials have been used to synthesize hard carbons but the impact of the precursors on the final properties of the anode material is not fully understood. In this study the impact of the biomass source on the structural and electrochemical properties of hard carbons is unraveled by using different, representative types of biomass as examples. The systematic structural and electrochemical investigation of hard carbons derived from different sources-namely corncobs, peanut shells, and waste apples, which are representative of hemicellulose-, lignin- and pectin-rich biomass, respectively-enables understanding and interlinking of the structural and electrochemical properties. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization.

PubMed

Abad, Sergi; Turon, Xavier

2015-12-05

Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA) when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM) with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10-0.12 h(-1)), biomass (0.7-0.8 g cells/g Substrate) and product (0.14-0.15 g DHA/g cells) yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct.

Effects of nitrogen and carbon sources on the production of inulinase from strain Bacillus sp. SG113

NASA Astrophysics Data System (ADS)

Gavrailov, Simeon; Ivanova, Viara

2016-03-01

The effects of the carbon and nitrogen substrates on the growth of Bacillus sp. SG113 strain were studied. The use of organic nitrogen sources (peptone, beef extract, yeast extract, casein) leads to rapid cellular growth and the best results for the Bacillus strain were obtained with casein hydrolysate. From the inorganic nitrogen sources studied, the (NH4) 2SO4 proved to be the best nitrogen source. Casein hydrolysate and (NH4) 2SO4 stimulated the invertase synthesis. In the presence of Jerusalem artichoke, onion and garlic extracts as carbon sources the strain synthesized from 6 to 10 times more inulinase.

A Heat and Mass Transfer Model of a Silicon Pilot Furnace

NASA Astrophysics Data System (ADS)

Sloman, Benjamin M.; Please, Colin P.; Van Gorder, Robert A.; Valderhaug, Aasgeir M.; Birkeland, Rolf G.; Wegge, Harald

2017-10-01

The most common technological route for metallurgical silicon production is to feed quartz and a carbon source ( e.g., coal, coke, or charcoal) into submerged-arc furnaces, which use electrodes as electrical conductors. We develop a mathematical model of a silicon furnace. A continuum approach is taken, and we derive from first principles the equations governing the time evolution of chemical concentrations, gas partial pressures, velocity, and temperature within a one-dimensional vertical section of a furnace. Numerical simulations are obtained for this model and are shown to compare favorably with experimental results obtained using silicon pilot furnaces. A rising interface is shown to exist at the base of the charge, with motion caused by the heating of the pilot furnace. We find that more reactive carbon reduces the silicon monoxide losses, while reducing the carbon content in the raw material mixture causes greater solid and liquid material to build-up in the charge region, indicative of crust formation (which can be detrimental to the silicon production process). We also comment on how the various findings could be relevant for industrial operations.

Proxy of monsoon seasonality in carbon isotopes from paleosols of the southern Chinese Loess Plateau

USGS Publications Warehouse

Wang, Hongfang; Follmer, L.R.

1998-01-01

Soil organic matter (SOM) and soil carbonate (SC) are common constituents in soils and are directly related to plant growth. SOM accumulates gradually from the decomposition of plant material over time, whereas SC formation is biased to dry-season soil-dissolved CO2 that derives from plant respiration during a drying phase of the growing season. In some mixed C3-C4 environments, the peak of C3 and C4 plant metabolism differs seasonally, and the carbon source that contributes to the SOM and SC can be different. Consequently, ??13C(SOM) values reflect an annual average of the floral biomass, but ??13C(SC) values reflect a seasonal aspect of the plant community. The relationship between ??13C(SC) and ??13C(SOM) is mainly controlled by how different the seasonal conditions are. Our results suggest that the relationship is a seasonal proxy that can be used to differentiate the seasonality effects of Indian, East Asian, and Siberian monsoons on the Chinese Loess Plateau during the last interglacial-glacial cycle.

Paleoproterozoic volcanic centers of the São Félix do Xingu region, Amazonian craton, Brazil: Hydrothermal alteration and metallogenetic potential

NASA Astrophysics Data System (ADS)

da Cruz, Raquel Souza; Fernandes, Carlos Marcello Dias; Villas, Raimundo Netuno Nobre; Juliani, Caetano; Monteiro, Lena Virgínia Soares; Lagler, Bruno; Misas, Carlos Mario Echeverri

2016-06-01

Geological, petrographic, scanning electron microscopy, and X-ray diffraction studies revealed hydrothermalized lithotypes evidenced by overprinted zones of potassic, propylitic, sericitic, and intermediate argillic alterations types, with pervasive and fracture-controlled styles, in Paleoproterozoic volcano-plutonic units of the São Félix do Xingu region, Amazonian craton, northern Brazil. The Sobreiro Formation presents propylitic (epidote + chlorite + carbonate + clinozoisite + sericite + quartz ± albite ± hematite ± pyrite), sericitic (sericite + quartz + carbonate), and potassic (potassic feldspar + hematite) alterations. The prehnite-pumpellyite pair that is common in geothermal fields also occurs in this unit. The Santa Rosa Formation shows mainly potassic (biotite + microcline ± magnetite), sericitic (sericite + quartz + carbonate ± chlorite ± gold), and intermediate argillic (montmorillonite + kaolinite/halloysite + illite) alterations. These findings strongly suggest the involvement of magma-sourced and meteoric fluids and draw attention to the metallogenetic potential of these volcanic units for Paleoproterozoic epithermal and rare and base metal porphyry-type mineralizations, similar to those already identified in other portions of the Amazonian craton.

Utilizing Diffusion Theory to predict carbon dioxide concentration in an indoor environment

NASA Astrophysics Data System (ADS)

Kramer, Andrew R.

This research details a new method of relating sources of carbon dioxide to carbon dioxide concentration in a room operating in a reduced ventilation mode by utilizing Diffusion Theory. The theoretical basis of this research involved solving Fick's Second Law of Diffusion in spherical coordinates for a source of carbon dioxide flowing at a constant rate and located in the center of an impermeable spherical boundary. The solution was developed using a Laplace Transformation. A spherical diffusion test chamber was constructed and used to validate and benchmark the developed theory. The method was benchmarked by using Dispersion Coefficients for large carbon dioxide flow rates due to diffusion induced convection. The theoretical model was adapted to model a room operating with restricted ventilation in the presence of a known, constant source of carbon dioxide. The room was modeled as a sphere of volume equal to the room and utilized a Dispersion Coefficient that is consistent with published values. The developed Diffusion Model successfully predicted the spatial concentration of carbon dioxide in a room operating in a reduced ventilation mode in the presence of a source of carbon dioxide. The flow rates of carbon dioxide that were used in the room are comparable to the average flow rate of carbon dioxide from a person during quiet breathing, also known as the Tidal Breathing. This indicates the Diffusion Model developed from this research has the potential to correlate carbon dioxide concentration with static occupancy levels which can lead to energy savings through a reduction in air exchange rates when low occupancy is detected.

Sublimation rates of carbon monoxide and carbon dioxide from comets at large heliocentric distances

NASA Technical Reports Server (NTRS)

Sekanina, Zdenek

1992-01-01

Using a simple model for outgassing from a small flat surface area, the sublimation rates of carbon monoxide and carbon dioxide, two species more volatile than water ice that are known to be present in comets, are calculated for a suddenly activated discrete source on the rotating nucleus. The instantaneous sublimation rate depends upon the comet's heliocentric distance and the Sun's zenith angle at the location of the source. The values are derived for the constants of CO and CO2 in an expression that yields the local rotation-averaged sublimation rate as a function of the comet's spin parameters and the source's cometocentric latitude.

Methods of forming semiconductor devices and devices formed using such methods

DOEpatents

Fox, Robert V; Rodriguez, Rene G; Pak, Joshua

2013-05-21

Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

Influence of carbon and lipid sources on variation of mercury and other trace elements in polar bears (Ursus maritimus).

PubMed

Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; McKinney, Melissa A; Peacock, Elizabeth; Sonne, Christian

2012-12-01

In the present study, the authors investigated the influence of carbon and lipid sources on regional differences in liver trace element (As, Cd, Cu, total Hg, Mn, Pb, Rb, Se, and Zn) concentrations measured in polar bears (Ursus maritimus) (n = 121) from 10 Alaskan, Canadian Arctic, and East Greenland subpopulations. Carbon and lipid sources were assessed using δ(13) C in muscle tissue and fatty acid (FA) profiles in subcutaneous adipose tissue as chemical tracers. A negative relationship between total Hg and δ(13) C suggested that polar bears feeding in areas with higher riverine inputs of terrestrial carbon accumulate more Hg than bears feeding in areas with lower freshwater input. Mercury concentrations were also positively related to the FA 20:1n-9, which is biosynthesized in large amounts in Calanus copepods. This result raises the hypothesis that Calanus glacialis are an important link in the uptake of Hg in the marine food web and ultimately in polar bears. Unadjusted total Hg, Se, and As concentrations showed greater geographical variation among polar bear subpopulations compared with concentrations adjusted for carbon and lipid sources. The Hg concentrations adjusted for carbon and lipid sources in Bering-Chukchi Sea polar bear liver tissue remained the lowest among subpopulations. Based on these findings, the authors suggest that carbon and lipid sources for polar bears should be taken into account when one is assessing spatial and temporal trends of long-range transported trace elements. Copyright © 2012 SETAC.

Implication of using different carbon sources for denitrification in wastewater treatments.

PubMed

Cherchi, Carla; Onnis-Hayden, Annalisa; El-Shawabkeh, Ibrahim; Gu, April Z

2009-08-01

Application of external carbon sources for denitrification becomes necessary for wastewater treatment plants that have to meet very stringent effluent nitrogen limits (e.g., 3 to 5 mgTN/L). In this study, we evaluated and compared three carbon sources--MicroC (Environmental Operating Solutions, Bourne, Massachusetts), methanol, and acetate-in terms of their denitrification rates and kinetics, effect on overall nitrogen removal performance, and microbial community structure of carbon-specific denitrifying enrichments. Denitrification rates and kinetics were determined with both acclimated and non-acclimated biomass, obtained from laboratory-scale sequencing batch reactor systems or full-scale plants. The results demonstrate the feasibility of the use of MicroC for denitrification processes, with maximum denitrification rates (k(dmax)) of 6.4 mgN/gVSSh and an observed yield of 0.36 mgVSS/mgCOD. Comparable maximum nitrate uptake rates were found with methanol, while acetate showed a maximum denitrification rate nearly twice as high as the others. The maximum growth rates measured at 20 degrees C for MicroC and methanol were 3.7 and 1.2 day(-1), respectively. The implications resulting from the differences in the denitrification rates and kinetics of different carbon sources on the full-scale nitrogen removal performance, under various configurations and operational conditions, were assessed using Biowin (EnviroSim Associates, Ltd., Flamborough, Ontario, Canada) simulations for both pre- and post-denitrification systems. Examination of microbial population structures using Automated Ribosomal Intergenic Spacer Analysis (ARISA) throughout the study period showed dynamic temporal changes and distinct microbial community structures of different carbon-specific denitrifying cultures. The ability of a specific carbon-acclimated denitrifying population to instantly use other carbon source also was investigated, and the chemical-structure-associated behavior patterns observed suggested that the complex biochemical pathways/enzymes involved in the denitrification process depended on the carbon sources used.

A defined, glucose-limited mineral medium for the cultivation of Listeria spp.

PubMed

Schneebeli, Rudolf; Egli, Thomas

2013-04-01

Members of the genus Listeria are fastidious bacteria with respect to their nutritional requirements, and several minimal media described in the literature fail to support growth of all Listeria spp. Furthermore, strict limitation by a single nutrient, e.g., the carbon source, has not been demonstrated for any of the published minimal media. This is an important prerequisite for defined studies of growth and physiology, including "omics." Based on a theoretical analysis of previously published mineral media for Listeria, an improved, well-balanced growth medium was designed. It supports the growth, not only of all tested Listeria monocytogenes strains, but of all other Listeria species, with the exception of L. ivanovii. The growth performance of L. monocytogenes strain Scott A was tested in the newly designed medium; glucose served as the only carbon and energy source for growth, whereas neither the supplied amino acids nor the buffering and complexing components (MOPS [morpholinepropanesulfonic acid] and EDTA) supported growth. Omission of amino acids, trace elements, or vitamins, alone or in combination, resulted in considerably reduced biomass yields. Furthermore, we monitored the specific growth rates of various Listeria strains cultivated in the designed mineral medium and compared them to growth in complex medium (brain heart infusion broth [BHI]). The novel mineral medium was optimized for the commonly used strain L. monocytogenes Scott A to achieve optimum cell yields and maximum specific growth rates. This mineral medium is the first published synthetic medium for Listeria that has been shown to be strictly carbon (glucose) limited.

Adsorption of microcystin-LR on mesoporous carbons and its potential use in drinking water source.

PubMed

Park, Jeong-Ann; Jung, Sung-Mok; Yi, In-Geol; Choi, Jae-Woo; Kim, Song-Bae; Lee, Sang-Hyup

2017-06-01

Microcystin-LR (MC-LR) is a common toxin derived from cyanobacterial blooms an effective, rapid and non-toxic method needs to be developed for its removal from drinking water treatment plants (DWTP). For an adsorption-based method, mesoporous carbon can be a promising supplemental adsorbent. The effect of mesoporous carbon (MC1, MC2, and MC3) properties and water quality parameters on the adsorption of MC-LR were investigated and the results were analyzed by kinetic, isotherm, thermodynamic, Derjaguin-Landau-Verwey-Overbeek (DLVO), and intraparticle diffusion models. MC1 was the most appropriate type for the removal of MC-LR with a maximum adsorption capacity of 35,670.49 μg/g. Adsorption of MC-LR is a spontaneous reaction dominated by van der Waals interactions. Pore sizes of 8.5-14 nm enhance the pore diffusion of MC-LR from the surface to the mesopores of MC1. The adsorption capacity was not sensitive to changes in the pH (3.2-8.0) and the existence of organic matter (2-5 mg/L). Furthermore, the final concentration of MC-LR was below the WHO guideline level after a 10-min reaction with 20 mg/L of MC1 in the Nak-Dong River, a drinking water source. The MC-LR adsorption mainly competed with humic substances (500-1000 g/mole); however, they did not have a great effect on adsorption. Copyright © 2017. Published by Elsevier Ltd.

Toward a Comprehensive Carbon Budget for North America: Potential Applications of Adjoint Methods with Diverse Datasets

NASA Technical Reports Server (NTRS)

Andrews, A.

2002-01-01

A detailed mechanistic understanding of the sources and sinks of CO2 will be required to reliably predict future COS levels and climate. A commonly used technique for deriving information about CO2 exchange with surface reservoirs is to solve an "inverse problem," where CO2 observations are used with an atmospheric transport model to find the optimal distribution of sources and sinks. Synthesis inversion methods are powerful tools for addressing this question, but the results are disturbingly sensitive to the details of the calculation. Studies done using different atmospheric transport models and combinations of surface station data have produced substantially different distributions of surface fluxes. Adjoint methods are now being developed that will more effectively incorporate diverse datasets in estimates of surface fluxes of CO2. In an adjoint framework, it will be possible to combine CO2 concentration data from long-term surface monitoring stations with data from intensive field campaigns and with proposed future satellite observations. A major advantage of the adjoint approach is that meteorological and surface data, as well as data for other atmospheric constituents and pollutants can be efficiently included in addition to observations of CO2 mixing ratios. This presentation will provide an overview of potentially useful datasets for carbon cycle research in general with an emphasis on planning for the North American Carbon Project. Areas of overlap with ongoing and proposed work on air quality/air pollution issues will be highlighted.

Data policy for data sets from various sources: recent developments in the Integrated Carbon Observation System (ICOS)

NASA Astrophysics Data System (ADS)

Vermeulen, A. T.; Kutsch, W. L.; Lavric, J. V.; Juurola, E.

2016-12-01

Fluxnet is facing a transition from single PI and project engagement to a cooperation of infrastructures such as ICOS, Ameriflux, NEON, Chinaflux or TERN. Each of these infrastructures has developed its own data life cycle, data license and data policy which will have implications on future cooperation within Fluxnet and other global data integration efforts such as e.g. SOCAt in the ocean community. This presentation will introduce into the recent developments of the ICOS data policy and show perspectives for future cooperation in global networks. The challenge in developing the ICOS data policy has been to find the best compromise between optimized access for users and sufficient visibility and acknowledgement of data providers. ICOS data will be provided under the Creative Commons 4.0 BY license. ICOS data will be provided through the ICOS Carbon Portal. Data usage will be absolutely unrestricted. Data have only to be attributed as ICOS data. With the attribution ICOS will provide a persistent identifier (pid, sometimes also nominated as digial object identifier, doi) that will direct to a landing page where data provider and if necessary also funding organisations are identified. In cooperation with other environmental research infrastructures in the framework of the European cluster project ENVRIplus and the Research Data Alliance (RDA) the ICOS Carbon Portal is currently developing a data citation system. This includes developing recommendations for data citation of integrated data sets from different sources.

Organic Biomarkers Along the River-Coastal Ocean Continuum: Human Activities and their Influence on Carbon Delivery (Invited)

NASA Astrophysics Data System (ADS)

Canuel, E. A.; Pondell, C. R.

2010-12-01

Human-induced changes in land-use and water diversion have modified the connectivity between upstream sources of organic carbon (OC) and their delivery to the coastal ocean. This connectivity will likely be further modified by climate variability. Biomarkers provide useful tools for tracing the delivery of terrigeous OC from the watershed to downstream environments. In this study, we used the Sacramento-San Joaquin River Delta CA and its watershed as a model system for understanding how human activities influenced delivery and composition of organic carbon (OC) over the past 50-60 years. Biomarker records, stable isotopes, and radiocarbon ages of bulk carbon signatures preserved in sediment cores were used to examine human impacts on carbon sources, amounts, and ages. Our presentation will discuss: 1) alterations in the sources of carbon preserved in the historical sedimentary record; and 2) environmental implications of such changes.

Saprotrophic fungal mycorrhizal symbionts in achlorophyllous orchids

PubMed Central

Martos, Florent; Perry, Brian A; Padamsee, Mahajabeen; Roy, Mélanie; Pailler, Thierry

2010-01-01

Mycoheterotrophic plants are achlorophyllous plants that obtain carbon from their mycorrhizal fungi. They are usually considered to associate with fungi that are (1) specific of each mycoheterotrophic species and (2) mycorrhizal on surrounding green plants, which are the ultimate carbon source of the entire system. Here we review recent works revealing that some mycoheterotrophic plants are not fungal-specific, and that some mycoheterotrophic orchids associate with saprophytic fungi. A re-examination of earlier data suggests that lower specificity may be less rare than supposed in mycoheterotrophic plants. Association between mycoheterotrophic orchids and saprophytic fungi arose several times in the evolution of the two partners. We speculate that this indirectly illustrates why transition from saprotrophy to mycorrhizal status is common in fungal evolution. Moreover, some unexpected fungi occasionally encountered in plant roots should not be discounted as ‘molecular scraps’, since these facultatively biotrophic encounters may evolve into mycorrhizal symbionts in some other plants. PMID:20061806

Oil mixing behavior after an oil spill: identification conflicts of different fingerprints.

PubMed

He, Shijie; Yu, Hongjun; Luo, Yongming; Wang, Chuanyuan; Li, Xueshuang; Li, Zhongping

2018-04-01

Clearing up whether spilled oil is mixed or not can strengthen the accuracy of oil spill identification. In the present study, the biomarkers in spilled oil samples were detected. The weathering modes of different types of diagnostic ratio and carbon isotope values of individual n-alkanes were also analyzed. The results showed that the diagnostic ratios of steroids, terpenes and aromatics, and weathering characteristics of carbon isotope composition (δ 13 C) of individual n-alkanes supported the idea that Dalian oil spill emerged from a single oil source. Furthermore, commonly used diagnostic ratios of n-alkanes indicated that the Dalian oil spill had undergone the oil mixing process. The different identifying outcomes indicate that some kinds of n-alkane-rich substance (such as oil dispersants) were mixed in the Dalian spilled oil and interfered with the routine diagnosis ratios of n-alkanes.

An improved high-performance lithium-air battery.

PubMed

Jung, Hun-Gi; Hassoun, Jusef; Park, Jin-Bum; Sun, Yang-Kook; Scrosati, Bruno

2012-06-10

Although dominating the consumer electronics markets as the power source of choice for popular portable devices, the common lithium battery is not yet suited for use in sustainable electrified road transport. The development of advanced, higher-energy lithium batteries is essential in the rapid establishment of the electric car market. Owing to its exceptionally high energy potentiality, the lithium-air battery is a very appealing candidate for fulfilling this role. However, the performance of such batteries has been limited to only a few charge-discharge cycles with low rate capability. Here, by choosing a suitable stable electrolyte and appropriate cell design, we demonstrate a lithium-air battery capable of operating over many cycles with capacity and rate values as high as 5,000 mAh g(carbon)(-1) and 3 A g(carbon)(-1), respectively. For this battery we estimate an energy density value that is much higher than those offered by the currently available lithium-ion battery technology.

Catabolism of exogenous deoxyinosine in cultured epithelial amniotic cells.

PubMed

Carta, M C; Mattana, A; Camici, M; Allegrini, S; Tozzi, M G; Sgarrella, F

2001-10-03

Uptake and catabolism of purine nucleosides have been commonly considered as means to salvage the purine ring for nucleic acid synthesis, usually neglecting the destiny of the pentose moiety. With the aim to ascertain if deoxyribose derived from exogenous DNA can be utilised as a carbon and energy source, we studied the catabolism of exogenous deoxyinosine in a cell line derived from human amnion epithelium (WISH). Intact WISH cells catabolise deoxyinosine by conversion into hypoxanthine. The nucleoside enters the cell through a nitrobenzylthioinosine-insensitive equilibrative transport. Deoxyinosine undergoes a phosphorolytic cleavage inside the cell. The purine base diffuses back to the external medium, while the phosphorylated pentose moiety can be further catabolised to glycolysis and citric acid cycle intermediates. Our results indicate that the catabolism of the deoxynucleoside can be considered mainly as a means to meet the carbon and energy requirements of growing cells.

High resolution carbon isotope of Crassostrea cuttakensis: A proxy for seasonally varying carbon dynamics in a tropical delta-estuary system

NASA Astrophysics Data System (ADS)

Sreemany, Arpita

2017-04-01

The exponential increase in the atmospheric CO2 concentration and global temperature is becoming a major threat to the existence of the mankind. It has been proposed that the ˜2 ˚ C rise in the average global temperature may lead to a point of no-return where the balance between the climate and the ecosystem collapses. Therefore, detailed understanding of the major carbon reservoirs and their mutual interactions is needed for better future climate prediction. Among all the reservoirs, ocean holds ˜90 % of the exogenic carbon and promotes long term storage in sediments. However, the majority of the sedimentary carbon is of terrestrial origin and transported through rivers, which play an important role in carbon exchange between the atmosphere, terrestrial biosphere, and oceans. The transportation of organic carbon through river does not follow a simple conveyer belt model. Various organic and inorganic reactions (i.e., organic carbon degradation, inorganic carbon precipitation, primary production, community respiration) modify the state of the carbon to form a major sub-reservoir in the river, i.e., Dissolved Inorganic Carbon (DIC). So, identifying the source/s of the DIC is crucial to understand the carbon dynamics in the river. Stable carbon isotopic composition of the DIC (δ13CDIC) has long been extensively used to reveal the dominant source/s of the DIC. The majority of the large rivers, being situated in the tropical belts, show seasonal fluctuation in the DIC sources. However, seasonal sampling in the remotest reaches of these rivers hindered our thorough understanding of the seasonally varying source/s of DIC in these rivers. Many calcifying organisms precipitate their shell carbonate in equilibrium with water and hence likely to record the δ13CDICof ambient water in their shell. In this study, a living oyster (Crassostrea cuttakensis) was collected from Matla River, which is part of the Ganges Brahmaputra river delta system, and analyzed for its stable isotopic composition (δ13Cshelland δ18Oshell). The oyster shell was cut along the maximum growth line and the umbo of the oyster was analyzed for the stable isotopic measurement. An online laser ablation system, attached to a Delta V Advantage Mass Spectrometer via. Gas-bench II, was used for very high resolution (˜125μm, equivalent to ˜6 days) isotope data. Additionally, water samples were collected from the study area in different seasons and the δ13CDICof the ambient water was analyzed. The shell carbonate δ13C profile shows excellent seasonal variation and very good correlation with the measured δ13CDIC. Though more water samples from different seasons are needed to accurately calibrate the vital effect of this species, it can be suggested from the limited dataset that the carbonate shell of this species was precipitated in equilibrium with the ambient water and can be used as a reliable proxy for the δ13CDIC.

Effects of nutrient load on microbial activities within a seagrass-dominated ecosystem: Implications of changes in seagrass blue carbon.

PubMed

Liu, Songlin; Jiang, Zhijian; Wu, Yunchao; Zhang, Jingping; Arbi, Iman; Ye, Feng; Huang, Xiaoping; Macreadie, Peter Ian

2017-04-15

Nutrient loading is a leading cause of global seagrass decline, triggering shifts from seagrass- to macroalgal-dominance. Within seagrass meadows of Xincun Bay (South China Sea), we found that nutrient loading (due to fish farming) increased sediment microbial biomass and extracellular enzyme activity associated with carbon cycling (polyphenol oxidase, invertase and cellulase), with a corresponding decrease in percent sediment organic carbon (SOC), suggesting that nutrients primed microorganism and stimulated SOC remineralization. Surpisingly, however, the relative contribution of seagrass-derived carbon to bacteria (δ 13 C bacteria ) increased with nutrient loading, despite popular theory being that microbes switch to consuming macroalgae which are assumed to provide a more labile carbon source. Organic carbon sources of fungi were unaffected by nutrient loading. Overall, this study suggests that nutrient loading changes the relative contribution of seagrass and algal sources to SOC pools, boosting sediment microbial biomass and extracellular enzyme activity, thereby possibly changing seagrass blue carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preliminary studies on the evolution of carbon assimilation abilities within Mucorales.

PubMed

Pawłowska, Julia; Aleksandrzak-Piekarczyk, Tamara; Banach, Agnieszka; Kiersztyn, Bartosz; Muszewska, Anna; Serewa, Lidia; Szatraj, Katarzyna; Wrzosek, Marta

2016-05-01

Representatives of Mucorales belong to one of the oldest lineages of terrestrial fungi. Although carbon is of fundamental importance for fungal growth and functioning, relatively little is known about enzymatic capacities of Mucorales. The evolutionary history and the variability of the capacity to metabolize different carbon sources among representatives of the order Mucorales was studied using Phenotypic Microarray Plates. The ability of 26 strains belonging to 23 nonpathogenic species of Mucorales to use 95 different carbon sources was tested. Intraspecies variability of carbon assimilation profiles was lower than interspecies variation for some selected strains. Although similarities between the phylogenetic tree and the dendrogram created from carbon source utilization data were observed, the ability of the various strains to use the analyzed substrates did not show a clear correlation with the evolutionary history of the group. Instead, carbon assimilation profiles are probably shaped by environmental conditions. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Measurements of Carbon Dioxide, Carbon Monoxide, and Other Related Tracers at High Spatial and Temporal Resolution in an Urban Environment

NASA Astrophysics Data System (ADS)

Rella, C.; Jacobson, G.

2012-04-01

The ability to quantify the sources and sinks of carbon dioxide on the urban scale is essential for understanding the atmospheric drivers to global climate change. In the 'top-down' approach, overall carbon fluxes are determined by combining remote measurements of carbon dioxide concentrations with complex atmospheric transport models, and these emissions measurements are compared to "bottoms-up" predictions based on detailed inventories of the sources and sinks of carbon, both anthropogenic and biogenic in nature. This approach, which has been proven to be effective at continental scales, becomes challenging to implement at the urban scale, due to poorly understood micrometeorological atmospheric transport models and high variability of the emissions sources in space (e.g., factories, highways, residences) and time (rush hours, factory shifts and shutdowns, residential energy usage variability during the day and over the year). New measurement and analysis techniques are required to make sense of the carbon dioxide signal in cities. Here we present detailed, high spatial- and temporal-resolution greenhouse gas measurements in Silicon Valley in California. The synthesis of two experimental campaigns is presented: real-time measurements from two ten-meter urban 'towers,' and ground-based mobile mapping measurements. Real-time carbon dioxide data from a nine-month period are combined with real-time carbon monoxide, methane, acetylene, and carbon 13 measurements to partition the observed CO2 concentrations between different anthropogenic sectors (e.g., transport, residential) and biogenic sources. The carbon monoxide to carbon dioxide ratio is shown to vary over more than a factor of two from season to season or even from day to night, indicating rapid and frequent shifts in the balance between different carbon dioxide sources. Clear differences are seen between the two urban sites, which are separated by 7 km. Further information is given by the carbon 13 signature and by acetylene, another tracer that provides complementary information to carbon monoxide as an indicator of combustion. In spring and summer, the combined signal of the urban center and the surrounding biosphere and urban green space is explored. These methods show great promise for quantifying and partitioning carbon dioxide emissions in an urban and mixed urban / ecological setting.

Using stable isotopes of carbon to investigate the seasonal variation of carbon transfer in a northwestern Arkansas cave

USGS Publications Warehouse

Knierim, Katherine J.; Pollock, Erik; Hays, Phillip D.; Khojasteh, Jam

2015-01-01

Stable-isotope analyses are valuable in karst settings, where characterizing biogeochemical cycling of carbon along groundwater flow paths is critical for understanding and protecting sensitive cave and karst water resources. This study quantified the seasonal changes in concentration and isotopic composition (δ13C) of aqueous and gaseous carbon species—dissolved inorganic carbon (DIC) and gaseous carbon dioxide (CO2)—to characterize sources and transfer of these species along a karst flow path, with emphasis on a cave environment. Gas and water samples were collected from the soil and a cave in northwestern Arkansas approximately once a month for one year to characterize carbon cycling along a conceptual groundwater flow path. In the soil, as the DIC concentration increased, the isotopic composition of the DIC became relatively lighter, indicating an organic carbon source for a component of the DIC and corroborating soil DIC as a proxy for soil respiration. In the cave, a positive correlation between DIC and surface temperature was due to increased soil respiration as the organic carbon signal from the soil was transferred to the cave environment via the aqueous phase. CO2 concentration was lowest in the cave during colder months and increased exponentially with increasing surface temperature, presumably due to higher rates of soil respiration during warmer periods and changing ventilation patterns between the surface and cave atmosphere. Isotopic disequilibrium between CO2 and DIC in the cave was greatest when CO2 concentration was changing during November/ December and March/April, presumably due to the rapid addition or removal of gaseous CO2. The isotopic disequilibrium between DIC and CO2 provided evidence that cave CO2 was a mixture of carbon from several sources, which was mostly constrained by mixture between atmospheric CO2 and soil CO2. The concentration and isotopic composition of gaseous and aqueous carbon species were controlled by month-to-month variations in temperature and precipitation and provided insight into the sources of carbon in the cave. Stable carbon isotope ratios provided an effective tool to explore carbon transfer from the soil zone and into the cave, identify carbon sources in the cave, and investigate how seasonality affected the transfer of carbon in a shallow karst system.

Impacts of crop rotations on soil organic carbon sequestration

NASA Astrophysics Data System (ADS)

Gobin, Anne; Vos, Johan; Joris, Ingeborg; Van De Vreken, Philippe

2013-04-01

Agricultural land use and crop rotations can greatly affect the amount of carbon sequestered in the soil. We developed a framework for modelling the impacts of crop rotations on soil carbon sequestration at the field scale with test case Flanders. A crop rotation geo-database was constructed covering 10 years of crop rotation in Flanders using the IACS parcel registration (Integrated Administration and Control System) to elicit the most common crop rotation on major soil types in Flanders. In order to simulate the impact of crop cover on carbon sequestration, the Roth-C model was adapted to Flanders' environment and coupled to common crop rotations extracted from the IACS geodatabases and statistical databases on crop yield. Crop allometric models were used to calculate crop residues from common crops in Flanders and subsequently derive stable organic matter fluxes to the soil (REGSOM). The REGSOM model was coupled to Roth-C model was run for 30 years and for all combinations of seven main arable crops, two common catch crops and two common dosages of organic manure. The common crops are winter wheat, winter barley, sugar beet, potato, grain maize, silage maize and winter rapeseed; the catch crops are yellow mustard and Italian ryegrass; the manure dosages are 35 ton/ha cattle slurry and 22 ton/ha pig slurry. Four common soils were simulated: sand, loam, sandy loam and clay. In total more than 2.4 million simulations were made with monthly output of carbon content for 30 years. Results demonstrate that crop cover dynamics influence carbon sequestration for a very large percentage. For the same rotations carbon sequestration is highest on clay soils and lowest on sandy soils. Crop residues of grain maize and winter wheat followed by catch crops contribute largely to the total carbon sequestered. This implies that agricultural policies that impact on agricultural land management influence soil carbon sequestration for a large percentage. The framework is therefore suited for further scenario analysis and impact assessment in order to support agri-environmental policy decisions.

Stream restoration and sewers impact sources and fluxes of water,carbon, and nutrients in urban watersheds

EPA Science Inventory

An improved understanding of sources and timing of water and nutrient fluxes associated with urban stream restoration is critical for guiding effective watershed management. We investigated how sources, fluxes, and flowpaths of water, carbon (C), nitrogen (N), and phosphorus (P)...

Radiocarbon Evidence of Active Endolithic Microbial Communities in the Hyperarid Core of the Atacama Desert

PubMed Central

Wierzchos, Jacek; Davila, Alfonso F.; Slater, Gregory F.

2013-01-01

Abstract The hyperarid core of the Atacama Desert is one of the driest and most inhospitable places on Earth, where life is most commonly found in the interior of rocks (i.e., endolithic habitats). Due to the extreme dryness, microbial activity in these habitats is expected to be low; however, the rate of carbon cycling within these microbial communities remains unknown. We address this issue by characterizing the isotopic composition (13C and 14C) of phospholipid fatty acids (PLFA) and glycolipid fatty acids (GLFA) in colonized rocks from four different sites inside the hyperarid core. δ13C results suggest that autotrophy and/or quantitative conversion of organic matter to CO2 are the dominant processes occurring with the rock. Most Δ14C signatures of PLFA and GLFA were consistent with modern atmospheric CO2, indicating that endoliths are using atmospheric carbon as a primary carbon source and are also cycling carbon quickly. However, at one site the PLFA contained 14C from atmospheric nuclear weapons testing that occurred during the 1950s and 1960s, indicating a decadal rate of carbon cycling. At the driest site (Yungay), based on the relative abundance and 14C content of GLFA and PLFA, there was evidence of possible preservation. Hence, in low-moisture conditions, glycolipids may persist while phospholipids are preferentially hydrolyzed. Key Words: Endoliths—Extremophile—Carbon isotopes—Radiocarbon—Lipids. Astrobiology 13, 607–616. PMID:23848470

Isotope source apportionment of carbonaceous aerosol as a function of particle size and thermal refractiveness

NASA Astrophysics Data System (ADS)

Masalaite, Agne; Holzinger, Rupert; Remeikis, Vidmantas; Röckmann, Thomas; Dusek, Ulrike

2016-04-01

The stable carbon isotopes can be used to get information about sources and processing of carbonaceous aerosol. We will present results from source apportionment of carbonaceous aerosol as a function of particle size thermal refractiveness. Separate source apportionment for particles smaller than 200 nm and for different carbon volatility classes are rarely reported and give new insights into aerosol sources in the urban environment. Stable carbon isotope ratios were measured for the organic carbon (OC) fraction and total carbon (TC) of MOUDI impactor samples that were collected on a coastal site (Lithuania) during the winter 2012 and in the city of Vilnius (Lithuania) during the winter of 2009. The 11 impactor stages spanned a size range from 0.056 to 18 μm, but only the 6 stages in the submicron range were analysed. The δ13C values of bulk total carbon (δ13CTC) were determined with an elemental analyser (Flash EA 1112) coupled with an isotope ratio mass spectrometer (Thermo Finnigan Delta Plus Advantage) (EA - IRMS). Meanwhile δ13COC was measured using thermal-desorption isotope ratio mass spectrometry (IRMS) system. This allows a rough separation of the more volatile OC fraction (desorbed in the oven of IRMS up to 250 0C) from the more refractory fraction (desorbed up to 400 0C). In this study we investigated the composition of organic aerosol desorbed from filter samples at different temperatures using the thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) technique. During winter-time in Lithuania we expect photochemistry and biogenic emissions to be of minor importance. The main sources of aerosol carbon should be fossil fuel and biomass combustion. In both sites, the coastal and the urban site, δ13C measurements give a clear indication that the source contributions differ for small and large particles. Small particles < 200 nm are depleted in 13C with respect to larger particles by 1 - 2 ‰Ṫhis shows that OC in small particle arises mainly from fossil fuel sources, whereas OC in larger particles from 200 nm to 1 μm has higher contribution from biomass burning/other sources. Moreover, there is a clear distinction in source contribution between the more volatile OC fraction and the more refractory fraction. The more refractory fraction is enriched in 13C by 1 to 2 ‰ for both small and large particles. These results show that the fossil fuel combustion is associated to a larger degree with more volatile carbon, whereas biomass burning is the main source of the more refractory particles. According to our source apportionment, the more volatile carbon fraction in the smallest particles is almost completely from fossil fuels, whereas the more refractory carbon fraction in the large size range is almost complete from biomass burning. The more refractory small particles and the less refractory large particles are roughly an even mix of these two sources. The detailed chemical speciation of the carbonaceous aerosol will be presented as well. Acknowledgements This study was funded by the Dutch Science Foundation (NWO grants Nr. 820.01.001, and 834.08.002).

40 CFR 458.36 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel... pollutant property-Oil and grease. Pretreatment standard-100mg/liter. [60 FR 33972, June 29, 1995] ...

40 CFR 458.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Furnace... pollutant property-Oil and grease. Pretreatment standard-100mg/liter. [60 FR 33972, June 29, 1995] ...

40 CFR 458.26 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal... pollutant property-Oil and grease. Pretreatment standard-100mg/liter. [60 FR 33972, June 29, 1995] ...

40 CFR 458.36 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Channel... pollutant property-Oil and grease. Pretreatment standard-100mg/liter. [60 FR 33972, June 29, 1995] ...

40 CFR 458.26 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Thermal... pollutant property-Oil and grease. Pretreatment standard-100mg/liter. [60 FR 33972, June 29, 1995] ...

40 CFR 458.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS (CONTINUED) CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Furnace... pollutant property-Oil and grease. Pretreatment standard-100mg/liter. [60 FR 33972, June 29, 1995] ...

40 CFR 458.46 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS CARBON BLACK MANUFACTURING POINT SOURCE CATEGORY Carbon Black Lamp Process... pollutants or pollutant properties controlled by this section which may be discharged to a publicly owned...

Distribution of organic carbon and petroleum source rock potential of Cretaceous and lower Tertiary carbonates, South Florida Basin: preliminary results

USGS Publications Warehouse

Palacas, James George

1978-01-01

Analyses of 134 core samples from the South Florida Basin show that the carbonates of Comanchean age are relatively richer in average organic carbon (0.41 percent) than those of Coahuilan age (0.28 percent), Gulfian age (0.18 percent) and Paleocene age (0.20 percent). They are also nearly twice as rich as the average world, wide carbonate (average 0.24 percent). The majority of carbonates have organic carbons less than 0.30 percent but the presence of many relatively organic rich beds composed of highly bituminous, argillaceous, highly stylolitic, and algal-bearing limestones and dolomites accounts for the higher percentage of organic carbon in some of the stratigraphic units. Carbonate rocks that contain greater than 0.4 percent organic carbon and that might be considered as possible petroleum sources were noted in almost each subdivision of the Coahuilan and Comanchean Series but particularly the units of Fredericksburg 'B', Trinity 'A', Trinity 'F', and Upper Sunniland. Possible source rocks have been ascribed by others to the Lower Sunniland, but lack of sufficient samples precluded any firm assessment in this initial report. In the shallower section of the basin, organic-rich carbonates containing as much as 3.2 percent organic carbon were observed in the lowermost part of the Gulfian Series and carbonate rocks with oil staining or 'dead' and 'live oil' were noted by others in the uppermost Gulfian and upper Cedar Keys Formation. It is questionable whether these shallower rocks are of sufficient thermal maturity to have generated commercial oil. The South Florida basin is still sparsely drilled and produces only from the Sunniland Limestone at an average depth of 11,500 feet (3500 m). Because the Sunniland contains good reservoir rocks and apparently adequate source rocks, and because the success rate of new oil field discoveries has increased in recent years, the chances of finding additional oil reserves in the Sunniland are promising. Furthermore, the presence of possible source rocks in many of the other stratigraphic units, in particular, the Fredericksburg, should give further impetus to exploring for other productive horizons.

Chemical Characterization of the Degradation of Necromass from Four Ascomycota Fungi: Implications for Soil Organic Carbon Turnover and Storage

NASA Astrophysics Data System (ADS)

Bruner, V. J.; Schreiner, K. M.; Blair, N. E.; Egerton, L.

2016-12-01

Terrestrial soils store vast amounts of organic carbon, approximately twice as much carbon as is currently in the atmospheric CO2 pool. Despite its importance in the global carbon cycle, much is still unknown about the source, turnover, and stability of this soil organic carbon (SOC) pool. For example, fungi are known to play an important role in shaping the chemistry of SOC by degrading common biopolymers, and fungal biomass has been found to be a significant portion of living microbial SOC, dominating over bacteria in some soils by as much as 90%. And yet, despite growing evidence that microbial necromass may be larger contributors to SOC than previously thought, very little is known about the specific degradation patterns of fungal necromass and subsequently its potential chemical contributions to long-lived SOC pools. This study addresses these knowledge gaps through a time-series analysis of the degradation patterns of fungal tissue from four different saprotrophic Ascomyota species in temperate restored prairie soils. Fungal tissue was buried in soils both within a temperature- and light-controlled laboratory environment, and in a field environment, and harvested at intervals from 1 day to two months. After harvest, chemical analysis of the dried tissue by thermochemolysis pyrolysis-GCMS was used for relative quantitation of a variety of common biomolecules and biopolymers within the fungal tissue that may be long lived in soils, including chitin, glucan, mannan, ergosterol, and melanin. The degradation of these specific molecules, bulk fungal tissue, and bulk C and N within the tissue, is modeled to (1) show that a small portion of fungal necromass persists in the environment even after the period of the experiment and could serve as a contributor to long-lived SOC, and (2) provide quantitative information on the contribution of fungal tissue to global SOC pools.

The role of African dust in the formation of Quaternary soils on Mallorca, Spain and implications for the genesis of Red Mediterranean soils

USGS Publications Warehouse

Muhs, D.R.; Budahn, J.; Avila, A.; Skipp, G.; Freeman, J.; Patterson, D.

2010-01-01

African dust additions explain the origin of terra rossa soils that are common on the carbonate-platform island of Mallorca, Spain. Mineralogical and geochemical analyses indicate that Quaternary carbonate eolianites on Mallorca have a very high purity, usually composed of more than 90% carbonate minerals (calcite, dolomite, and aragonite). In contrast, terra rossa soils developed on these eolianites have lower carbonate contents and contain higher concentrations of quartz and other silicates. Analyses of immobile trace elements indicate that the non-carbonate fractions of the eolianites have distinctive Zr/Hf, La/Yb, Cr/Sc and Th/Ta values that differ from the superjacent terra rossa soils. These observations indicate that even if sufficient dissolution of the eolianite had taken place to create the soils by residual accumulation, immobile element ratios in the soils require an external source. However, Zr/Hf, La/Yb, Cr/Sc and Th/Ta values in the soils fall within the range of values for these element ratios in African dust collected on Barbados and mainland Spain. We conclude that the silicate fractions of terra rossa soils on Mallorca are derived mainly, though not wholly, from far-traveled African dust, and this process may explain the origin of other terra rossa soils found in southern Europe. ?? 2010.

Variation in Baiting Intensity Among CO2-Baited Traps Used to Collect Hematophagous Arthropods.

PubMed

Springer, Yuri P; Taylor, Jeffrey R; Travers, Patrick D

2015-01-01

Hematophagous arthropods transmit the etiological agents of numerous diseases and as a result are frequently the targets of sampling to characterize vector and pathogen populations. Arguably, the most commonly used sampling approach involves traps baited with carbon dioxide. We report results of a laboratory study in which the performance of carbon dioxide-baited traps was evaluated using measures of baiting intensity, the amount of carbon dioxide released per unit time during trap deployment. We evaluated the effects of trap design, carbon dioxide source, and wind speed on baiting intensity and documented significant effects of these factors on the length of sampling (time to baiting intensity = 0), maximum baiting intensity, and variation in baiting intensity during experimental trials. Among the three dry ice-baited trap types evaluated, traps utilizing insulated beverage coolers as dry ice containers sampled for the longest period of time, had the lowest maximum but most consistent baiting intensity within trials and were least sensitive to effects of wind speed and dry ice form (block vs. pellet) on baiting intensity. Results of trials involving traps baited with carbon dioxide released from pressurized cylinders suggested that this trap type had performance comparable to dry ice-baited insulated cooler traps but at considerably higher cost. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Modeling Source Water Threshold Exceedances with Extreme Value Theory

NASA Astrophysics Data System (ADS)

Rajagopalan, B.; Samson, C.; Summers, R. S.

2016-12-01

Variability in surface water quality, influenced by seasonal and long-term climate changes, can impact drinking water quality and treatment. In particular, temperature and precipitation can impact surface water quality directly or through their influence on streamflow and dilution capacity. Furthermore, they also impact land surface factors, such as soil moisture and vegetation, which can in turn affect surface water quality, in particular, levels of organic matter in surface waters which are of concern. All of these will be exacerbated by anthropogenic climate change. While some source water quality parameters, particularly Total Organic Carbon (TOC) and bromide concentrations, are not directly regulated for drinking water, these parameters are precursors to the formation of disinfection byproducts (DBPs), which are regulated in drinking water distribution systems. These DBPs form when a disinfectant, added to the water to protect public health against microbial pathogens, most commonly chlorine, reacts with dissolved organic matter (DOM), measured as TOC or dissolved organic carbon (DOC), and inorganic precursor materials, such as bromide. Therefore, understanding and modeling the extremes of TOC and Bromide concentrations is of critical interest for drinking water utilities. In this study we develop nonstationary extreme value analysis models for threshold exceedances of source water quality parameters, specifically TOC and bromide concentrations. In this, the threshold exceedances are modeled as Generalized Pareto Distribution (GPD) whose parameters vary as a function of climate and land surface variables - thus, enabling to capture the temporal nonstationarity. We apply these to model threshold exceedance of source water TOC and bromide concentrations at two locations with different climate and find very good performance.

The effect of toxic carbon source on the reaction of activated sludge in the batch reactor.

PubMed

Wu, Changyong; Zhou, Yuexi; Zhang, Siyu; Xu, Min; Song, Jiamei

2018-03-01

The toxic carbon source can cause higher residual effluent dissolved organic carbon than easily biodegraded carbon source in activated sludge process. In this study, an integrated activated sludge model is developed as the tool to understand the mechanism of toxic carbon source (phenol) on the reaction, regarding the carbon flows during the aeration period in the batch reactor. To estimate the toxic function of phenol, the microbial cells death rate (k death ) is introduced into the model. The integrated model was calibrated and validated by the experimental data and it was found the model simulations matched the all experimental measurements. In the steady state, the toxicity of phenol can result in higher microbial cells death rate (0.1637 h -1 vs 0.0028 h -1 ) and decay rate coefficient of biomass (0.0115 h -1 vs 0.0107 h -1 ) than acetate. In addition, the utilization-associated products (UAP) and extracellular polymeric substances (EPS) formation coefficients of phenol are higher than that of acetate, indicating that more carbon flows into the extracellular components, such as soluble microbial products (SMP), when degrading toxic organics. In the non-steady state of feeding phenol, the yield coefficient for growth and maximum specific growth rate are very low in the first few days (1-10 d), while the decay rate coefficient of biomass and microbial cells death rate are relatively high. The model provides insights into the difference of the dynamic reaction with different carbon sources in the batch reactor. Copyright © 2017 Elsevier Ltd. All rights reserved.

Calcic soils and calcretes in the southwestern United States

USGS Publications Warehouse

Bachman, George Odell; Machette, Michael N.

1977-01-01

Secondary calcium carbonate of diverse origins, 'caliche' of many authors, is widespread in the southwestern United States. 'Caliche' includes various carbonates such as calcic soils and products of groundwater cementation. The term 'caliche' is generally avoided in this report in favor of such terms as calcrete, calcic soils, and pervasively cemented deposits. Criteria for the recognition of various types of calcrete of diverse origins include field relations and laboratory data. Calcic soils provide a comprehensive set of characteristics that aid in their recognition in the field. These characteristics include a distinctive morphology that is zoned horizontally and can frequently be traced over tens to hundreds of square kilometers. The major process in the formation of pedogenic calcrete and calic soils is the leaching of calcium carbonate from upper soil horizons by downward percolating soil solutions and reprecipitation of the carbonate in alluvial horizons near the base of the soil profile. The formation of pedogenic calcrete involves many factors including climate, source of carbonate, and tectonic stability of the geomorphic surface on which the calcrete is deposited. Most of the carbonate in pedogenic calcrete is probably derived from windblown sand, dust, and rain. Calcic soils and pedogenic calcretes follow a six-stage sequence morphologic development and is based on a classification devised by Gile, Peterson and Grossman in 1966. The .six morphologic stages of carbonate deposition in soils are related to the relative age of the soil and are as follows: I. The first or youngest stage includes filamentous or faint coatings of carbonate on detrital grains. II. The second stage includes pebble coatings which are continuous; firm carbonate nodules are few to common. III. The third stage includes coalesced nodules which occur in a friable or disseminated carbonate matrix. IV. The fourth stage includes platy, firmly cemented matrix which engulfs nodules; horizon is plugged to downward moving solutions. V. The fifth stage includes soils which are platy to tabular, dense, strongly cemented. A well-developed laminar layer occurs on the upper surface. VI. The sixth and most advanced stage is massive, multilaminar, and strongly cemented calcrete with abundant pisoliths, the upper surface of which may be brecciated. Pisoliths may indicate many generations of brecciation and reformation. In general calcic soils include stages I through III and are friable to moderately indurated; whereas pedogenic calcretes include stages IV through VI and are dense and strongly indurated. In a single pedon the morphologic stage of carbonate deposition decreases downward in the profile. The stage of development may be used in local regions for correlation and determination of relative ages of soils and geomorphic surfaces. Some structures observed in pedogenic calcretes may be present in other types of calcrete but the horizontal zonation typical of deposits of soil processes is absent. Laminar structure in particular is not restricted to pedogenic deposits and is common in many varieties of calcrete. Very little chemical change occurs in the noncalcareous nonclayey fractions of calcretes with age; but clay minerals within calcretes undergo a complex history of authigenesis. There is a depletion of magnesium in the calcareous portion and an enrichment of magnesium in the clayey portion of a calcrete with age. In keeping with this relationship, montmorillonite, or mixed layer montmorillonite-illite, is common in younger calcretes; whereas the high magnesium-silicate clays, sepiolite and palygorskite, are common in older calcretes. This indicates that the magnesium depleted from the carbonate is redistributed authigenically in clay minerals. The mobility of carbonate introduces many problems in attempts to date calcretes directly. Although the relative ages of soils within a province may be determined by quant

Process Parameters for Successful Synthesis of Carbon Nanotubes by Chemical Vapor Deposition: Implications for Chemical Mechanisms and Life-cycle Assessment

NASA Astrophysics Data System (ADS)

Xue, Ke

Manufacturing of carbon nanotubes (CNTs) via chemical vapor deposition (CVD) calls for thermal treatment associated with gas-phase rearrangement and catalyst deposition to achieve high cost efficiency and limited influence on environmental impact. Taking advantage of higher degree of structure control and economical efficiency, catalytic chemical vapor deposition (CCVD) has currently become the most prevailing synthesis approach for the synthesis of large-scale pure CNTs in past years. Because the synthesis process of CNTs dominates the potential ecotoxic impacts, materials consumption, energy consumption and greenhouse gas emissions should be further limited to efficiently reduce life cycle ecotoxicity of carbon naotubes. However, efforts to reduce energy and material requirements in synthesis of CNTs by CCVD are hindered by a lack of mechanistic understanding. In this thesis, the effect of operating parameters, especially the temperature, carbon source concentration, and residence time on the synthesis were studied to improve the production efficiency in a different angle. Thus, implications on the choice of operating parameters could be provided to help the synthesis of carbon nanotubes. Here, we investigated the typical operating parameters in conditions that have yielded successful CNT production in the published academic literature of over seventy articles. The data were filtered by quality of the resultant product and deemed either "successful" or "unsuccessful" according to the authors. Furthermore, growth rate data were tabulated and used as performance metric for the process whenever possible. The data provided us an opportunity to prompt possible and common methods for practioners in the synthesis of CNTs and motivate routes to achieve energy and material minimization. The statistical analysis revealed that methane and ethylene often rely on thermal conversion process to form direct carbon precursor; further, methane and ethylene could not be the direct CNT precursors by themselves. Acetylene does not show an additional energy demand or thermal conversion in the synthesis, and it could be the direct CNT precursors by itself; or at least, it would be most easily to get access to carbon nanotube growth while minimizing synthesis temperature. In detail, methane employs more energy demand (Tavg=883°C) than ethylene (Tavg=766°C), which in turn demands more energy than acetylene (Tavg=710°C) to successfully synthesize carbon nanotubes. The distinction in energy demand could be the result of kinetic energy requirements by the thermal conversion process of methane and ethylene to form direct CNT precursors, and methane employs the highest activation demand among three hydrocarbons. Thus, these results support the hypothesis that methane and ethylene could be thermally converted to form acetylene before CNT incorporation. In addition, methane and ethylene show the demand for hydrogen in thermal conversion process before CNT incorporation; whereas, hydrogen does not contribute to the synthesis via acetylene before CNT incorporation, except the reduction of catalyst. At relatively low hydrogen concentration, this work suggests that hydrogen prompts growth of carbon nanotubes via methane and ethylene, probably by reducing the catalysts or participating thermal reactions. In addition, "polymerization-like formation mechanism" could be supported by the higher growth rate of CNTs via ethylene than acetylene. There could be an optimum residence time to maintain a relatively higher growth rate. At too low residence time, carbon source could not be accumulated, causing a waste of material; while too high residence time may cause the limitation of carbon source supplement and accumulation of byproducts. At last, high concentration of carbon source and hydrogen could cause more energy consumption, while it helps to achieve a high growth rate, due to the more presence of direct carbon precursor.

Effect of Different Carbon Sources on Bacterial Nanocellulose Production and Structure Using the Low pH Resistant Strain Komagataeibacter Medellinensis

PubMed Central

Molina-Ramírez, Carlos; Castro, Margarita; Osorio, Marlon; Torres-Taborda, Mabel; Gómez, Beatriz; Zuluaga, Robin; Gómez, Catalina; Gañán, Piedad; Rojas, Orlando J.; Castro, Cristina

2017-01-01

Bacterial cellulose (BC) is a polymer obtained by fermentation with microorganism of different genera. Recently, new producer species have been discovered, which require identification of the most important variables affecting cellulose production. In this work, the influence of different carbon sources in BC production by a novel low pH-resistant strain Komagataeibacter medellinensis was established. The Hestrin-Schramm culture medium was used as a reference and was compared to other media comprising glucose, fructose, and sucrose, used as carbon sources at three concentrations (1, 2, and 3% w/v). The BC yield and dynamics of carbon consumption were determined at given fermentation times during cellulose production. While the carbon source did not influence the BC structural characteristics, different production levels were determined: glucose > sucrose > fructose. These results highlight considerations to improve BC industrial production and to establish the BC property space for applications in different fields. PMID:28773001

Vapor phase diamond growth technology

NASA Technical Reports Server (NTRS)

Angus, J. C.

1981-01-01

Ion beam deposition chambers used for carbon film generation were designed and constructed. Features of the developed equipment include: (1) carbon ion energies down to approx. 50 eV; (2) in suit surface monitoring with HEED; (3) provision for flooding the surface with ultraviolet radiation; (4) infrared laser heating of substrate; (5) residual gas monitoring; (6) provision for several source gases, including diborane for doping studies; and (7) growth from either hydrocarbon source gases or from carbon/argon arc sources. Various analytical techniques for characterization of from carbon/argon arc sources. Various analytical techniques for characterization of the ion deposited carbon films used to establish the nature of the chemical bonding and crystallographic structure of the films are discussed. These include: H2204/HN03 etch; resistance measurements; hardness tests; Fourier transform infrared spectroscopy; scanning auger microscopy; electron spectroscopy for chemical analysis; electron diffraction and energy dispersive X-ray analysis; electron energy loss spectroscopy; density measurements; secondary ion mass spectroscopy; high energy electron diffraction; and electron spin resonance. Results of the tests are summarized.

Hydrologic support of carbon dioxide flux revealed by whole-lake carbon budgets

USGS Publications Warehouse

Stets, E.G.; Striegl, Robert G.; Aiken, G.R.; Rosenberry, D.O.; Winter, T.C.

2009-01-01

Freshwater lakes are an important component of the global carbon cycle through both organic carbon (OC) sequestration and carbon dioxide (CO 2) emission. Most lakes have a net annual loss of CO2 to the atmosphere and substantial current evidence suggests that biologic mineralization of allochthonous OC maintains this flux. Because net CO 2 flux to the atmosphere implies net mineralization of OC within the lake ecosystem, it is also commonly assumed that net annual CO2 emission indicates negative net ecosystem production (NEP). We explored the relationship between atmospheric CO2 emission and NEP in two lakes known to have contrasting hydrologie characteristics and net CO2 emission. We calculated NEP for calendar year 2004 using whole-lake OC and inorganic carbon (IC) budgets, NEPoc and NEPIC, respectively, and compared the resulting values to measured annual CO 2 flux from the lakes. In both lakes, NEPIc and NEP Ic were positive, indicating net autotrophy. Therefore CO2 emission from these lakes was apparently not supported by mineralization of allochthonous organic material. In both lakes, hydrologie CO2 inputs, as well as CO2 evolved from netcalcite precipitation, could account for the net CO2 emission. NEP calculated from diel CO2 measurements was also affected by hydrologie inputs of CO2. These results indicate that CO2 emission and positive NEP may coincide in lakes, especially in carbonate terrain, and that all potential geologic, biogeochemical, and hydrologie sources of CO2 need to be accounted for when using CO2 concentrations to infer lake NEP. Copyright 2009 by the American Geophysical Union.

Fluoride content in bottled drinking waters, carbonated soft drinks and fruit juices in Davangere city, India.

PubMed

Thippeswamy, H M; Kumar, Nanditha; Anand, S R; Prashant, G M; Chandu, G N

2010-01-01

The regular ingestion of fluoride lowers the prevalence of dental caries. The total daily intake of fluoride for optimal dental health should be 0.05-0.07 mg fluoride/kg body weight and to avoid the risk of dental fluorosis, the daily intake should not exceed a daily level of 0.10 mg fluoride/kg body weight. The main source of fluoride is from drinking water and other beverages. As in other countries, consumption of bottled water, juices and carbonated beverages has increased in our country. To analyze the fluoride content in bottled water, juices and carbonated soft drinks that were commonly available in Davangere city. Three samples of 10 commercially available brands of bottled drinking water, 12 fruit juices and 12 carbonated soft drinks were purchased. Bottled water and carbonated soft drinks were stored at a cold place until fluoride analysis was performed and a clear juice was prepared using different fruits without the addition of water. Then, the fluoride analysis was performed. The mean and standard deviation of fluoride content of bottled water, fruit juices and carbonated soft drinks were measured, which were found to be 0.20 mg (±0.19) F/L, 0.29 mg (±0.06) F/L and 0.22 mg (±0.05) F/L, respectively. In viewing the results of the present study, it can be concluded that regulation of the optimal range of fluoride in bottled drinking water, carbonated soft drinks and fruit juices should be drawn for the Indian scenario.

Copolymerization of Epoxides and CO[subscript 2]: Polymer Chemistry for Incorporation in Undergraduate Inorganic Chemistry

ERIC Educational Resources Information Center

Darensbourg, Donald J.

2017-01-01

Because fossil fuels are a nonrenewable resource, alternative sources of chemical carbon will be necessary as petroleum based chemicals decline during the 21st century. Carbon dioxide can serve as a source of carbon for the synthesis of useful chemicals, thereby contributing to a sustainable chemical industry. A promising technology for…

Tracing the source of soil organic matter eroded from temperate forest catchments using carbon and nitrogen isotopes

Treesearch

Emma P. McCorkle; Asmeret Asefaw Berhe; Carolyn T. Hunsaker; Dale W. Johnson; Karis J. McFarlane; Marilyn L. Fogel; Stephen C. Hart

2016-01-01

Soil erosion continuously redistributes soil and associated soil organic matter (SOM) on the Earth's surface, with important implications for biogeochemical cycling of essential elements and terrestrial carbon sequestration. Despite the importance of soil erosion, surprisingly few studies have evaluated the sources of eroded carbon (C). We used natural abundance...

Organic carbon export from the Greenland Ice Sheet: sources, sinks and downstream fluxes

NASA Astrophysics Data System (ADS)

Wadham, J. L.; Lawson, E.; Tranter, M.; Stibal, M.; Telling, J.; Lis, G. P.; Nienow, P. W.; Anesio, A. M.; Butler, C. E.

2012-12-01

Runoff from small glacier systems has been shown to contain dissolved organic carbon (DOC) rich in low molecular weight (LMW), and hence more labile forms, designating glaciers as an important source of carbon for downstream heterotrophic activity. Here we assess glacier surfaces as potential sources of labile DOC to downstream ecosystems, presenting data from a wide range of glacier systems to determine sources and sinks of DOC in glacial and proglacial systems. We subsequently focus upon the Greenland Ice Sheet (GrIS) which is the largest source of glacial runoff at present (400 km3 yr-1), with predicted increases in future decades. We report high fluxes of particulate organic carbon (POC), DOC and LMW labile fractions from a large GrIS catchment during two contrasting melt seasons. POC dominates OC export, is sourced from the ice sheet bed and contains a significant bioreactive component (~10% carbohydrates). The LMW-DOC "labile" fraction derives almost entirely from microbial activity on the ice sheet surface, which is supported by data from glacier systems also presented here. Annual fluxes of DOC, POC and labile components were lower in 2010 than 2009, despite a ~2 fold increase in runoff fluxes in 2010, suggesting production-limited DOC/POC sources. Scaled to the entire ice sheet, combined DOC and POC fluxes are of a similar order of magnitude to other large Arctic river systems and may represent an important source of organic carbon to the North Atlantic, Greenland and Labrador Seas.

Limitation of using Angstrom exponent for source apportionment of black carbon in complex environments - A case study from the North West Indo- Gangetic plain

NASA Astrophysics Data System (ADS)

Garg, S.; Sinha, B.; Sinha, V.; Chandra, P.; Sarda Esteve, R.; Gros, V.

2015-12-01

Determining the contribution of different sources to the total BC is necessary for targeted mitigation. Absorption Angstrom exponent (αabs) measurements of black carbon (BC) have recently been introduced as a novel tool to apportion the contribution of biomass burning sources to BC. Two-component Aethalometer model for apportioning BC to biomass burning sources and fossil fuel combustion sources, which uses αabs as a generic indicator of the source type, is widely used for determining the contribution of the two types of sources to the total BC. Our work studies BC emissions in the highly-populated, anthropogenic emissions-dominated Indo-Gangetic Plain and demonstrates that the αabs cannot be used as a generic tracer for biomass burning emissions in a complex environment. Simultaneously collected high time resolution data from a 7-wavelength Aethalometer (AE 42, Magee Scientific, USA) and a high sensitivity Proton Transfer Reaction- Quadrupole Mass Spectrometer (PTR-MS) installed at a sub-urban site in Mohali (Punjab), India, were used to identify a number of biomass combustion plumes during which BC enhancements correlated strongly with an increase in acetonitrile (a well-established biomass burning tracer) mixing ratio. Each type of biomass combustion is classified and characterized by distinct emission ratios of aromatic compounds and oxygenated VOCs to acetonitrile. The identified types of biomass combustion include two different types of crop residue burning (paddy and wheat), burning of leaf-litter, and garbage burning. Traffic (fossil-fuel burning) plumes were also selected for comparison. We find that the two-component Aethalometer source-apportionment method cannot be extrapolated to all types of biomass combustion and αabs of traffic plumes can be >1 in developing countries like India, where use of adulterated fuel in vehicles is common. Thus in a complex environment, where multiple anthropogenic BC sources and air masses of variable photochemical age impact a receptor site, the angstrom exponent is not representative of the combustion type and therefore, cannot be used as a generic tracer to constrain source contributions.

Taking climate, land use, and social economy into estimation of carbon budget in the Guanzhong-Tianshui Economic Region of China.

PubMed

Li, Ting; Li, Jing; Zhou, Zixiang; Wang, Yanze; Yang, Xiaonan; Qin, Keyu; Liu, Jingya

2017-04-01

Carbon sequestration is an indispensable ecosystem service provided by soil and vegetation, so mapping and valuing the carbon budget by considering both ecological and social factors is an important trend in evaluating ecosystem services. In this work, we established multiple scenarios to evaluate the impacts of land use change, population growth, carbon emission per capita, and carbon markets on carbon budget. We quantified carbon sinks (aboveground and belowground) under different scenarios, using the Carnegie-Ames-Stanford Approach (CASA) model and an improved carbon cycle process model, and studied carbon sources caused by human activities by analyzing the spatial distribution of human population and carbon emission per capita. We also assessed the net present value (NPV) for carbon budgets under different carbon price and discount rate scenarios using NPV model. Our results indicate that the carbon budget of Guanzhong-Tianshui Economic Region is surplus: Carbon sinks range from 1.50 × 10 10 to 1.54 × 10 10  t, while carbon sources caused by human activities range from 2.76 × 10 5 to 7.60 × 10 5  t. And the NPV for carbon deficits range from 3.20 × 10 11 RMB to 1.52 × 10 12 RMB. From the perspective of ecological management, deforestation, urban sprawl, population growth, and excessive carbon consumption are considered as the main challenges in balancing carbon sources and sinks. Levying carbon tax would be a considerable option when decision maker develops carbon emission reduction policies. Our results provide a scientific and credible reference for harmonious and sustainable development in the Guanzhong-Tianshui Economic Region of China.

Numerical Comparison of NASA's Dual Brayton Power Generation System Performance Using CO2 or N2 as the Working Fluid

NASA Technical Reports Server (NTRS)

Ownens, Albert K.; Lavelle, Thomas M.; Hervol, David S.

2010-01-01

A Dual Brayton Power Conversion System (DBPCS) has been tested at the NASA Glenn Research Center using Nitrogen (N2) as the working fluid. This system uses two closed Brayton cycle systems that share a common heat source and working fluid but are otherwise independent. This system has been modeled using the Numerical Propulsion System Simulation (NPSS) environment. This paper presents the results of a numerical study that investigated system performance changes resulting when the working fluid is changed from gaseous (N2) to gaseous carbon dioxide (CO2).

Response of a piezoelectric pressure transducer to IR laser beam impingement

NASA Technical Reports Server (NTRS)

Smith, William C.; Leiweke, Robert J.; Beeson, Harold

1992-01-01

The non-pressure response of a PCB Model 113A transducer to a far infrared radiation impulse from a carbon dioxide laser was investigated. Incident radiation was applied both to the bare transducer diaphragm and to coated diaphragms. Coatings included two common ablative materials and a reflective gold coating. High-flux radiation impulses induced an immediate brief negative output followed by a longer-duration positive output. Both timing and amplitude of the responses will be discussed, and the effects of coatings will be compared. Bursts of blackbody radiation from a 1500 K source produced qualitatively similar responses.

What drives uncertainty in model diagnoses of carbon dynamics in southern US forests: climate, vegetation, disturbance, or model parameters?

NASA Astrophysics Data System (ADS)

Zhou, Y.; Gu, H.; Williams, C. A.

2017-12-01

Results from terrestrial carbon cycle models have multiple sources of uncertainty, each with its behavior and range. Their relative importance and how they combine has received little attention. This study investigates how various sources of uncertainty propagate, temporally and spatially, in CASA-Disturbance (CASA-D). CASA-D simulates the impact of climatic forcing and disturbance legacies on forest carbon dynamics with the following steps. Firstly, we infer annual growth and mortality rates from measured biomass stocks (FIA) over time and disturbance (e.g., fire, harvest, bark beetle) to represent annual post-disturbance carbon fluxes trajectories across forest types and site productivity settings. Then, annual carbon fluxes are estimated from these trajectories by using time since disturbance which is inferred from biomass (NBCD 2000) and disturbance maps (NAFD, MTBS and ADS). Finally, we apply monthly climatic scalars derived from default CASA to temporally distribute annual carbon fluxes to each month. This study assesses carbon flux uncertainty from two sources: driving data including climatic and forest biomass inputs, and three most sensitive parameters in CASA-D including maximum light use efficiency, temperature sensitivity of soil respiration (Q10) and optimum temperature identified by using EFAST (Extended Fourier Amplitude Sensitivity Testing). We quantify model uncertainties from each, and report their relative importance in estimating forest carbon sink/source in southeast United States from 2003 to 2010.

Monitoring by Control Technique - Activated Carbon Adsorber

EPA Pesticide Factsheets

Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about Activated Carbon Adsorber control techniques used to reduce pollutant emissions.

Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization

PubMed Central

Abad, Sergi; Turon, Xavier

2015-01-01

Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA) when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM) with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10–0.12 h−1), biomass (0.7–0.8 g cells/g Substrate) and product (0.14–0.15 g DHA/g cells) yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct. PMID:26690180

Optimization of VFAs and ethanol production with waste sludge used as the denitrification carbon source.

PubMed

Guo, Liang; Zhang, Jiawen; Yin, Li; Zhao, Yangguo; Gao, Mengchun; She, Zonglian

2015-01-01

An acidification metabolite such as volatile fatty acids (VFAs) and ethanol could be used as denitrification carbon sources for solving the difficult problem of carbon source shortages and low nitrogen removal efficiency. A proper control of environmental factors could be essential for obtaining the optimal contents of VFAs and ethanol. In this study, suspended solids (SS), oxidation reduction potential (ORP) and shaking rate were chosen to investigate the interactive effects on VFAs and ethanol production with waste sludge. It was indicated that T-VFA yield could be enhanced at lower ORP and shaking rate. Changing the SS, ORP and shaking rate could influence the distribution of acetic, propionic, butyric, valeric acids and ethanol. The optimal conditions for VFAs and ethanol production used as a denitrification carbon source were predicted by analyzing response surface methodology (RSM).

A fungal transcription factor essential for starch degradation affects integration of carbon and nitrogen metabolism

DOE PAGES

Xiong, Yi; Wu, Vincent W.; Lubbe, Andrea; ...

2017-05-03

In Neurospora crassa, the transcription factor COL-26 functions as a regulator of glucose signaling and metabolism. Its loss leads to resistance to carbon catabolite repression. Here, we report that COL-26 is necessary for the expression of amylolytic genes in N. crassa and is required for the utilization of maltose and starch. Additionally, the Δcol-26 mutant shows growth defects on preferred carbon sources, such as glucose, an effect that was alleviated if glutamine replaced ammonium as the primary nitrogen source. This rescue did not occur when maltose was used as a sole carbon source. Transcriptome and metabolic analyses of the Δcol-26more » mutant relative to its wild type parental strain revealed that amino acid and nitrogen metabolism, the TCA cycle and GABA shunt were adversely affected. Phylogenetic analysis showed a single col-26 homolog in Sordariales, Ophilostomatales, and the Magnaporthales, but an expanded number of col-26 homologs in other filamentous fungal species. Deletion of the closest homolog of col-26 in Trichoderma reesei, bglR, resulted in a mutant with similar preferred carbon source growth deficiency, and which was alleviated if glutamine was the sole nitrogen source, suggesting conservation of COL-26 and BglR function. Our finding provides novel insight into the role of COL-26 for utilization of starch and in integrating carbon and nitrogen metabolism for balanced metabolic activities for optimal carbon and nitrogen distribution.« less

A fungal transcription factor essential for starch degradation affects integration of carbon and nitrogen metabolism

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

Xiong, Yi; Wu, Vincent W.; Lubbe, Andrea

In Neurospora crassa, the transcription factor COL-26 functions as a regulator of glucose signaling and metabolism. Its loss leads to resistance to carbon catabolite repression. Here, we report that COL-26 is necessary for the expression of amylolytic genes in N. crassa and is required for the utilization of maltose and starch. Additionally, the Δcol-26 mutant shows growth defects on preferred carbon sources, such as glucose, an effect that was alleviated if glutamine replaced ammonium as the primary nitrogen source. This rescue did not occur when maltose was used as a sole carbon source. Transcriptome and metabolic analyses of the Δcol-26more » mutant relative to its wild type parental strain revealed that amino acid and nitrogen metabolism, the TCA cycle and GABA shunt were adversely affected. Phylogenetic analysis showed a single col-26 homolog in Sordariales, Ophilostomatales, and the Magnaporthales, but an expanded number of col-26 homologs in other filamentous fungal species. Deletion of the closest homolog of col-26 in Trichoderma reesei, bglR, resulted in a mutant with similar preferred carbon source growth deficiency, and which was alleviated if glutamine was the sole nitrogen source, suggesting conservation of COL-26 and BglR function. Our finding provides novel insight into the role of COL-26 for utilization of starch and in integrating carbon and nitrogen metabolism for balanced metabolic activities for optimal carbon and nitrogen distribution.« less

A fungal transcription factor essential for starch degradation affects integration of carbon and nitrogen metabolism

PubMed Central

Xiong, Yi; Qin, Lina; Kennedy, Megan; Bauer, Diane; Barry, Kerrie; Northen, Trent R.; Grigoriev, Igor V.

2017-01-01

In Neurospora crassa, the transcription factor COL-26 functions as a regulator of glucose signaling and metabolism. Its loss leads to resistance to carbon catabolite repression. Here, we report that COL-26 is necessary for the expression of amylolytic genes in N. crassa and is required for the utilization of maltose and starch. Additionally, the Δcol-26 mutant shows growth defects on preferred carbon sources, such as glucose, an effect that was alleviated if glutamine replaced ammonium as the primary nitrogen source. This rescue did not occur when maltose was used as a sole carbon source. Transcriptome and metabolic analyses of the Δcol-26 mutant relative to its wild type parental strain revealed that amino acid and nitrogen metabolism, the TCA cycle and GABA shunt were adversely affected. Phylogenetic analysis showed a single col-26 homolog in Sordariales, Ophilostomatales, and the Magnaporthales, but an expanded number of col-26 homologs in other filamentous fungal species. Deletion of the closest homolog of col-26 in Trichoderma reesei, bglR, resulted in a mutant with similar preferred carbon source growth deficiency, and which was alleviated if glutamine was the sole nitrogen source, suggesting conservation of COL-26 and BglR function. Our finding provides novel insight into the role of COL-26 for utilization of starch and in integrating carbon and nitrogen metabolism for balanced metabolic activities for optimal carbon and nitrogen distribution. PMID:28467421

Quantifying terrestrial ecosystem carbon dynamics in the Jinsha watershed, Upper Yangtze, China from 1975 to 2000

USGS Publications Warehouse

Zhao, Shuqing; Liu, Shuguang; Yin, Runsheng; Li, Zhengpeng; Deng, Yulin; Tan, Kun; Deng, Xiangzheng; Rothstein, David; Qi, Jiaguo; Yin, Runsheng

2009-01-01

Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon storage and loss. Here we use the General Ensemble Biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China's upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sinks/source pattern showed a high degree of spatial heterogeneity, Carbon sinks were associated with forest areas without disturbances, whereas carbon Sources were primarily caused by stand-replacing disturbances. This highlights the importance of land-use history in determining the regional carbon sinks/source pattern.

Carbide-Derived Carbons with Tunable Porosity Optimized for Hydrogen Storage

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

Fisher, John E.; Gogotsi, Yury; Yildirim, Taner

2010-01-07

On-board hydrogen storage is a key requirement for fuel cell-powered cars and trucks. Porous carbon-based materials can in principle adsorb more hydrogen per unit weight at room temperature than liquid hydrogen at -176 oC. Achieving this goal requires interconnected pores with very high internal surface area, and binding energies between hydrogen and carbon significantly enhanced relative to H2 on graphite. In this project a systematic study of carbide-derived carbons, a novel form of porous carbon, was carried out to discover a high-performance hydrogen sorption material to meet the goal. In the event we were unable to improve on the statemore » of the art in terms of stored hydrogen per unit weight, having encountered the same fundamental limit of all porous carbons: the very weak interaction between H2 and the carbon surface. On the other hand we did discover several strategies to improve storage capacity on a volume basis, which should be applicable to other forms of porous carbon. Further discoveries with potentially broader impacts include • Proof that storage performance is not directly related to pore surface area, as had been previously claimed. Small pores (< 1.5 nm) are much more effective in storing hydrogen than larger ones, such that many materials with large total surface areas are sub-par performers. • Established that the distribution of pore sizes can be controlled during CDC synthesis, which opens the possibility of developing high performance materials within a common family while targeting widely disparate applications. Examples being actively pursued with other funding sources include methane storage, electrode materials for batteries and supercapacitors with record high specific capacitance, and perm-selective membranes which bind cytokines for control of infections and possibly hemodialysis filters.« less

Glucose repression in Saccharomyces cerevisiae.

PubMed

Kayikci, Ömur; Nielsen, Jens

2015-09-01

Glucose is the primary source of energy for the budding yeast Saccharomyces cerevisiae. Although yeast cells can utilize a wide range of carbon sources, presence of glucose suppresses molecular activities involved in the use of alternate carbon sources as well as it represses respiration and gluconeogenesis. This dominant effect of glucose on yeast carbon metabolism is coordinated by several signaling and metabolic interactions that mainly regulate transcriptional activity but are also effective at post-transcriptional and post-translational levels. This review describes effects of glucose repression on yeast carbon metabolism with a focus on roles of the Snf3/Rgt2 glucose-sensing pathway and Snf1 signal transduction in establishment and relief of glucose repression. © FEMS 2015.

Estimating the seasonal carbon source-sink geography of a natural, steady-state terrestrial biosphere

NASA Technical Reports Server (NTRS)

Box, Elgene O.

1988-01-01

The estimation of the seasonal dynamics of biospheric-carbon sources and sinks to be used as an input to global atmospheric CO2 studies and models is discussed. An ecological biosphere model is given and the advantages of the model are examined. Monthly maps of estimated biospheric carbon source and sink regions and estimates of total carbon fluxes are presented for an equilibrium terrestrial biosphere. The results are compared with those from other models. It is suggested that, despite maximum variations of atmospheric CO2 in boreal latitudes, the enormous contributions of tropical wet-dry regions to global atmospheric CO2 seasonality can not be ignored.

Malate as a key carbon source of leaf dark-respired CO2 across different environmental conditions in potato plants

PubMed Central

Lehmann, Marco M.; Rinne, Katja T.; Blessing, Carola; Siegwolf, Rolf T. W.; Buchmann, Nina; Werner, Roland A.

2015-01-01

Dissimilation of carbon sources during plant respiration in support of metabolic processes results in the continuous release of CO2. The carbon isotopic composition of leaf dark-respired CO2 (i.e. δ 13 C R) shows daily enrichments up to 14.8‰ under different environmental conditions. However, the reasons for this 13C enrichment in leaf dark-respired CO2 are not fully understood, since daily changes in δ13C of putative leaf respiratory carbon sources (δ 13 C RS) are not yet clear. Thus, we exposed potato plants (Solanum tuberosum) to different temperature and soil moisture treatments. We determined δ 13 C R with an in-tube incubation technique and δ 13 C RS with compound-specific isotope analysis during a daily cycle. The highest δ 13 C RS values were found in the organic acid malate under different environmental conditions, showing less negative values compared to δ 13 C R (up to 5.2‰) and compared to δ 13 C RS of soluble carbohydrates, citrate and starch (up to 8.8‰). Moreover, linear relationships between δ 13 C R and δ 13 C RS among different putative carbon sources were strongest for malate during daytime (r2=0.69, P≤0.001) and nighttime (r2=0.36, P≤0.001) under all environmental conditions. A multiple linear regression analysis revealed δ 13 C RS of malate as the most important carbon source influencing δ 13 C R. Thus, our results strongly indicate malate as a key carbon source of 13C enriched dark-respired CO2 in potato plants, probably driven by an anapleurotic flux replenishing intermediates of the Krebs cycle. PMID:26139821

Occupational carbon monoxide poisoning in the State of Washington, 1994-1999.

PubMed

Lofgren, Don J

2002-04-01

Carbon monoxide poisonings continue to be significant and preventable for a number of work operations. This study assesses occupational carbon monoxide morbidity and mortality for the state of Washington based on a review of workers' compensation records for the years 1994-1999. The study characterizes sources, industries, and causative factors, and further attempts to identify work operations most at risk. Records were identified by both injury source and diagnostic codes. The study limits itself to non-fire-related carbon monoxide poisonings and primarily those from acute exposure. A decline in the number of claims was not evident, but the number of incidents per year showed a slight decline. Carbon monoxide poisonings were found to occur throughout all types of industries. The greatest number of claims was found in agriculture, followed by construction and wholesale trade, with these three accounting for more than half the claims and nearly half of the incidents. The more severe poisonings did not necessarily occur in industries with the greatest number of incidents. The major source for carbon monoxide poisoning was forklift trucks, followed by auto/truck/bus, portable saws, and more than 20 other sources. Fruit packing and storage had the highest number of incidents mostly due to fuel-powered forklift activity, with nearly half of the incidents occurring in cold rooms. Adverse health effects as measured by carboxyhemoglobin, hyperbaric oxygen treatment, unconsciousness, and number and cost of claims were indexed by source. Though several specific work operations were identified, the episodic nature of carbon monoxide poisonings, as well as the diverse industries and sources, and the opportunity for a severe poisoning in any number of operations, poses challenges for effective intervention.

Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation

NASA Astrophysics Data System (ADS)

Bourke, Michael F.; Marriott, Philip J.; Glud, Ronnie N.; Hasler-Sheetal, Harald; Kamalanathan, Manoj; Beardall, John; Greening, Chris; Cook, Perran L. M.

2017-01-01

Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to bacteria and archaea. Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon is produced predominantly as a result of anaerobic eukaryotic metabolic activity. In our experiments, anaerobic production of dissolved inorganic carbon was consistently accompanied by large dissolved H2 production rates, suggesting the presence of fermentation. The production of both dissolved inorganic carbon and H2 persisted following administration of broad spectrum bactericidal antibiotics, but ceased following treatment with metronidazole. Metronidazole inhibits the ferredoxin/hydrogenase pathway of fermentative eukaryotic H2 production, suggesting that pathway as the source of H2 and dissolved inorganic carbon production. Metabolomic analysis showed large increases in lipid production at the onset of anoxia, consistent with documented pathways of anoxic dark fermentation in microalgae. Cell counts revealed a predominance of microalgae in the sediments. H2 production was observed in dark anoxic cultures of diatoms (Fragilariopsis sp.) and a chlorophyte (Pyramimonas) isolated from the study site, substantiating the hypothesis that microalgae undertake fermentation. We conclude that microalgal dark fermentation could be an important energy-conserving pathway in permeable sediments.

Metabolism in anoxic permeable sediments is dominated by eukaryotic dark fermentation

PubMed Central

Bourke, Michael F; Marriott, Philip J.; Glud, Ronnie N.; Hasler-Sheetal, Harald; Kamalanathan, Manoj; Beardall, John; Greening, Chris; Cook, Perran L.M.

2016-01-01

Permeable sediments are common across continental shelves and are critical contributors to marine biogeochemical cycling. Organic matter in permeable sediments is dominated by microalgae, which as eukaryotes have different anaerobic metabolic pathways to prokaryotes such as bacteria and archaea. Here we present analyses of flow-through reactor experiments showing that dissolved inorganic carbon is produced predominantly as a result of anaerobic eukaryotic metabolic activity. In our experiments, anaerobic production of dissolved inorganic carbon was consistently accompanied by large dissolved H2 production rates, suggesting the presence of fermentation. The production of both dissolved inorganic carbon and H2 persisted following administration of broad spectrum bactericidal antibiotics, but ceased following treatment with metronidazole. Metronidazole inhibits the ferredoxin/hydrogenase pathway of fermentative eukaryotic H2 production, suggesting that pathway as the source of H2 and dissolved inorganic carbon production. Metabolomic analysis showed large increases in lipid production at the onset of anoxia, consistent with documented pathways of anoxic dark fermentation in microalgae. Cell counts revealed a predominance of microalgae in the sediments. H2 production was observed in dark anoxic cultures of diatoms (Fragilariopsis sp.) and a chlorophyte (Pyramimonas) isolated from the study site, substantiating the hypothesis that microalgae undertake fermentation. We conclude that microalgal dark fermentation could be an important energy-conserving pathway in permeable sediments. PMID:28070216

Measurements of carbon utilization by single bacterial species in sterile soil: insights into Rhizobium spp.

PubMed

Wigley, K; Wakelin, S A; Moot, D J; Hammond, S; Ridgway, H J

2016-08-01

The aim of this work was to develop a tool to investigate the influence of soil factors on carbon utilization activity of single micro-organisms. The assay for Rhizobium leguminosarum bv. trifolii in γ-irradiated soil, using the MicroResp(™) system, was optimized for sterility, incubation time, and moisture level. The optimized method was validated with experiments that assessed (i) differences in C utilization of different rhizobia strains and (ii) how this was affected by soil type. Carbon utilization differed among strains of the same species (and symbiovar), but some strains were more responsive to the soil environment than others. This novel modification of the MicroResp(™) has enabled the scope of carbon-utilization patterns of single strains of bacteria, such as Rh. leguminosarum bv. trifolii, to be studied in soil. The system is a new tool with applications in microbial ecology adaptable to the study of many culturable bacterial and fungal soil-borne taxa. It will allow measurement of a micro-organism's ability to utilize common C sources released in rhizosphere exudates to be measured in a physical soil background. This knowledge may improve selection efficiency and deployment of commercial microbial inoculants. © 2016 The Society for Applied Microbiology.

Nano-molybdenum carbide/carbon nanotubes composite as bifunctional anode catalyst for high-performance Escherichia coli-based microbial fuel cell.

PubMed

Wang, Yaqiong; Li, Bin; Cui, Dan; Xiang, Xingde; Li, Weishan

2014-01-15

A novel electrode, carbon felt-supported nano-molybdenum carbide (Mo2C)/carbon nanotubes (CNTs) composite, was developed as platinum-free anode of high performance microbial fuel cell (MFC). The Mo2C/CNTs composite was synthesized by using the microwave-assisted method with Mo(CO)6 as a single source precursor and characterized by using X-ray diffraction and transmission electron microscopy. The activity of the composite as anode electrocatalyst of MFC based on Escherichia coli (E. coli) was investigated with cyclic voltammetry, chronoamperometry, and cell discharge test. It is found that the carbon felt electrode with 16.7 wt% Mo Mo2C/CNTs composite exhibits a comparable electrocatalytic activity to that with 20 wt% platinum as anode electrocatalyst. The superior performance of the developed platinum-free electrode can be ascribed to the bifunctional electrocatalysis of Mo2C/CNTs for the conversion of organic substrates into electricity through bacteria. The composite facilitates the formation of biofilm, which is necessary for the electron transfer via c-type cytochrome and nanowires. On the other hand, the composite exhibits the electrocatalytic activity towards the oxidation of hydrogen, which is the common metabolite of E. coli. © 2013 Elsevier B.V. All rights reserved.

Radiocarbon determination of fossil and contemporary carbon contribution to aerosol in the Pacific Islands.

PubMed

Isley, C F; Nelson, P F; Taylor, M P; Williams, A A; Jacobsen, G E

2018-06-21

Combustion emissions are of growing concern across all Pacific Island Countries, which account for >10,000 km 2 of the earth's surface area; as for many other small island states globally. Apportioning emissions inputs for Suva, the largest Pacific Island city, will aid in development of emission reduction strategies. Total suspended particulate (TSP) and fine particulate (PM 2.5 ) samples were collected for Suva City, a residential area (Kinoya, TSP) and a mainly ocean-influenced site (Suva Point, TSP) from 2014 to 2015. Percentages of contemporary and fossil carbon were determined by radiocarbon analysis (accelerator mass spectrometry); for non‑carbonate carbon (NCC), elemental carbon (EC) and organic carbon (OC). Source contributions to particulate matter were identified and the accuracy of previous emissions inventory and source apportionment studies was evaluated. Suva Point NCC concentrations (2.7 ± 0.4 μg/m 3 ) were four times lower than for City (13 ± 2 μg/m 3 in TSP) and Kinoya (13 ± 1 μg/m 3 in TSP); demonstrating the contribution of land-based emissions activities in city and residential areas. In Suva City, total NCC in air was 81% (79%-83%) fossil carbon, from vehicles, shipping, power generation and industry; whilst in the residential area, 48% (46%-50%) of total NCC was contemporary carbon; reflecting the higher incidence of biomass and waste burning and of cooking activities. Secondary organic fossil carbon sources contributed >36% of NCC mass at the city and >29% at Kinoya; with biogenic carbon being Kinoya's most significant source (approx. 30% of NCC mass). These results support the previous source apportionment studies for the city area; yet show that, in line with emissions inventory studies, biomass combustion contributes more PM 2.5 mass in residential areas. Hence air quality management strategies need to target open burning activities as well as fossil fuel combustion. Copyright © 2018 Elsevier B.V. All rights reserved.

Medical Significance of Microorganisms in Spacecraft Environment

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Ott, C. Mark

2007-01-01

Microorganisms can spoil food supplies, contaminate drinking water, release noxious volatile compounds, initiate allergic responses, contaminate the environment, and cause infectious diseases. International acceptability limits have been established for bacterial and fungal contaminants in air and on surfaces, and environmental monitoring is conducted to ensure compliance. Allowable levels of microorganism in water and food have also been established. Environmental monitoring of the space shuttle, the Mir, and the ISS have allowed for some general conclusions. Generally, the bacteria found in air and on interior surfaces are largely of human origin such as Staphylococcus spp., Micrococcus spp. Common environmental genera such as Bacillus spp. are the most commonly isolated bacteria from all spacecraft. Yeast species associated with humans such as Candida spp. are commonly found. Aspergillus spp., Penicillium spp., and Cladosporium spp. are the most commonly isolated filamentous fungi. Microbial levels in the environment differ significantly depending upon humidity levels, condensate accumulation, and availability of carbon sources. However, human "normal flora" of bacteria and fungi can result in serious, life-threatening diseases if human immunity is compromised. Disease incidence is expected to increase as mission duration increases.

Differences in carbon source usage by dental plaque in children with and without early childhood caries

PubMed Central

Zhao, Yan; Zhong, Wen-Jie; Xun, Zhe; Zhang, Qian; Song, Ye-Qing; Liu, Yun-Song; Chen, Feng

2017-01-01

Early childhood caries (ECC) is a considerable pediatric and public health problem worldwide. Preceding studies have focused primarily on bacterial diversity at the taxonomic level. Although these studies have provided significant information regarding the connection between dental caries and oral microbiomes, further comprehension of this microbial community’s ecological relevance is limited. This study identified the carbon source metabolic differences in dental plaque between children with and without ECC. We compared the microbial community functional diversity in 18 caries-free subjects with 18 severe ECC patients based on sole carbon source usage using a Biolog assay. The anaerobic microbial community in the ECC patients displayed greater metabolic activity than that of the control group. Specific carbon source metabolism differed significantly between the two groups. Subjects from the two groups were well distinguished by cluster and principal component analyses based on discriminative carbon sources. Our results implied that the microbial functional diversity between the ECC patients and healthy subjects differed significantly. In addition, the Biolog assay furthered our understanding of oral microbiomes as a composite of functional abilities, thus enabling us to identify the ecologically relevant functional differences among oral microbial communities.

Host carbon sources modulate cell wall architecture, drug resistance and virulence in a fungal pathogen

PubMed Central

Ene, Iuliana V; Adya, Ashok K; Wehmeier, Silvia; Brand, Alexandra C; MacCallum, Donna M; Gow, Neil A R; Brown, Alistair J P

2012-01-01

The survival of all microbes depends upon their ability to respond to environmental challenges. To establish infection, pathogens such as Candida albicans must mount effective stress responses to counter host defences while adapting to dynamic changes in nutrient status within host niches. Studies of C. albicans stress adaptation have generally been performed on glucose-grown cells, leaving the effects of alternative carbon sources upon stress resistance largely unexplored. We have shown that growth on alternative carbon sources, such as lactate, strongly influence the resistance of C. albicans to antifungal drugs, osmotic and cell wall stresses. Similar trends were observed in clinical isolates and other pathogenic Candida species. The increased stress resistance of C. albicans was not dependent on key stress (Hog1) and cell integrity (Mkc1) signalling pathways. Instead, increased stress resistance was promoted by major changes in the architecture and biophysical properties of the cell wall. Glucose- and lactate-grown cells displayed significant differences in cell wall mass, ultrastructure, elasticity and adhesion. Changes in carbon source also altered the virulence of C. albicans in models of systemic candidiasis and vaginitis, confirming the importance of alternative carbon sources within host niches during C. albicans infections. PMID:22587014

Accelerated benzene polycarboxylic acid analysis by liquid chromatography-time-of-flight-mass spectrometry for the determination of petrogenic and pyrogenic carbon.

PubMed

Hindersmann, Benjamin; Achten, Christine

2017-08-11

Pyrogenic carbon species are of particular interest due to their ubiquitous occurrence in the environment and their high sorption capacities for nonpolar organic compounds. It has recently been shown that the analysis of the molecular markers for complex aromatic carbon structures, benzene polycarboxylic acids (BPCA), has a high potential for aid in the identification of different carbon sources. In this study, the first LC method using mass spectrometry (MS) for reliable and accelerated (<24h) quantification of pyrogenic and petrogenic carbon by BPCA analysis has been developed. The main advantage of LC-MS compared to previous methods is the higher sensitivity, which is important if only small sample amounts are available. Sample pre-treatment could be reduced to a minimum. Deuterated phthalic acid was introduced as internal standard due to its structural similarity to BPCA and its lack of occurrence in the environment. Linear quantification with r 2 ≥0997 was accomplished for all BPCA. Method validation showed an excellent quantification reproducibility (mean CV<5%) which is comparable to LC-DAD methods and more reliable than GC-FID measurements (CV 16-23%). In summary, the presented BPCA method is more economic, efficient and presumably attractive to use. Besides reference materials, various pyrogenic and petrogenic samples were analyzed to test if the sources were indicated by BPCA analysis. In addition to pyrogenic carbon, large amounts of petrogenic carbon species can also be present in urban soils and river sediments, especially in mining regions. They also to a large degree consist of aromatic carbon structures and therefore have an impact on source identification by BPCA analysis. Comparison of petrogenic and pyrogenic carbon samples shows similarities in the BPCA concentrations and patterns, in their aromaticity and degree of aromatic condensation. Thus, a differentiation between petrogenic and pyrogenic carbon only by BPCA analysis of samples with unknown carbon sources is not possible. For reliable source identification of the carbon species, the combination with other methods, such as e. g. analysis of polycyclic aromatic hydrocarbons may be successful. Copyright © 2017 Elsevier B.V. All rights reserved.

REPORT TO CONGRESS ON BLACK CARBON

EPA Science Inventory

The Report to Congress on Black Carbon describes domestic and international sources of black carbon emissions, and summarizes available scientific information on the climate effects of black carbon. Further, the Report evaluates available black carbon mitigation options and thei...

The fabrication of carbon nanotube field-effect transistors with semiconductors as the source and drain contact materials.

PubMed

Xiao, Z; Camino, F E

2009-04-01

Sb(2)Te(3) and Bi(2)Te(2)Se semiconductor materials were used as the source and drain contact materials in the fabrication of carbon nanotube field-effect transistors (CNTFETs). Ultra-purified single-walled carbon nanotubes (SWCNTs) were ultrasonically dispersed in N-methyl pyrrolidone solvent. Dielectrophoresis was used to deposit and align SWCNTs for fabrication of CNTFETs. The Sb(2)Te(3)- and Bi(2)Te(2)Se-based CNTFETs demonstrate p-type metal-oxide-silicon-like I-V curves with high on/off drain-source current ratio at large drain-source voltages and good saturation of drain-source current with increasing drain-source voltage. The fabrication process developed is novel and has general meaning, and could be used for the fabrication of SWCNT-based integrated devices and systems with semiconductor contact materials.

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).

Investigation of black and brown carbon multiple-wavelength-dependent light absorption from biomass and fossil fuel combustion source emissions

Treesearch

Michael R. Olson; Mercedes Victoria Garcia; Michael A. Robinson; Paul Van Rooy; Mark A. Dietenberger; Michael Bergin; James Jay Schauer

2015-01-01

Quantification of the black carbon (BC) and brown carbon (BrC) components of source emissions is critical to understanding the impact combustion aerosols have on atmospheric light absorption. Multiple-wavelength absorption was measured from fuels including wood, agricultural biomass, coals, plant matter, and petroleum distillates in controlled combustion settings....

Method 415.3, Rev. 1.2: Determination of Total Organic Carbon and Specific UV Absorbance at 254 nm in Source Water and Drinking Water

EPA Science Inventory

This method provides procedures for the determination of total organic carbon (TOC), dissolved organic carbon (DOC), and UV absorption at 254 nm (UVA) in source waters and drinking waters. The DOC and UVA determinations are used in the calculation of the Specific UV Absorbance (S...

Factors influencing buyers' willingness to offer price premiums for carbon credits sourced from urban forests

Treesearch

N.C. Poudyal; J.M. Bowker; J.P. Siry

2015-01-01

Marketing carbon offset credits generated by urban forest projects could help cities and local governments achieve their financial self-sufficiency and environmental sustainability goals. Understanding the value of carbon credits sourced from urban forests, and the factors that determine buyers’ willingness to pay a premium for such credits could benefit cities in...