WorldWideScience

Sample records for co2 uptake due

  1. CO2 uptake potential due to concrete carbonation: A case study

    Directory of Open Access Journals (Sweden)

    Edna Possan

    2017-06-01

    Full Text Available The cement manufacturing process accounts for about 5% CO2 (carbon dioxide released into the atmosphere. However, during its life cycle, concrete may capture CO2 through carbonation, in order to, partially, offset the impact of its production. Thus, this paper aims at studying the CO2 uptake potential of the Itaipu Dam due to concrete carbonation of such material. So, 155 cores were extracted from the concrete dam in different points to measure carbonation depth. In order to evaluate its influence on carbonation, the measurement of internal moisture distribution in concrete was also carried out. The results have shown that carbonation takes part of the whole dam area, indicating CO2 uptake potential. Up to the present moment, 13,384 tons of CO2 have been absorbed by concrete carbonation of the Itaipu Dam.

  2. Assessing the potential long-term increase of oceanic fossil fuel CO2 uptake due to CO2-calcification feedback

    Directory of Open Access Journals (Sweden)

    T. M. Lenton

    2007-07-01

    Full Text Available Plankton manipulation experiments exhibit a wide range of sensitivities of biogenic calcification to simulated anthropogenic acidification of the ocean, with the "lab rat" of planktic calcifiers, Emiliania huxleyi apparently not representative of calcification generally. We assess the implications of this observational uncertainty by creating an ensemble of realizations of an Earth system model that encapsulates a comparable range of uncertainty in calcification response to ocean acidification. We predict that a substantial reduction in marine carbonate production is possible in the future, with enhanced ocean CO2 sequestration across the model ensemble driving a 4–13% reduction in the year 3000 atmospheric fossil fuel CO2 burden. Concurrent changes in ocean circulation and surface temperatures in the model contribute about one third to the increase in CO2 uptake. We find that uncertainty in the predicted strength of CO2-calcification feedback seems to be dominated by the assumption as to which species of calcifier contribute most to carbonate production in the open ocean.

  3. Carbonation and CO2 uptake of concrete

    International Nuclear Information System (INIS)

    Yang, Keun-Hyeok; Seo, Eun-A; Tae, Sung-Ho

    2014-01-01

    This study developed a reliable procedure to assess the carbon dioxide (CO 2 ) uptake of concrete by carbonation during the service life of a structure and by the recycling of concrete after demolition. To generalize the amount of absorbable CO 2 per unit volume of concrete, the molar concentration of carbonatable constituents in hardened cement paste was simplified as a function of the unit content of cement, and the degree of hydration of the cement paste was formulated as a function of the water-to-cement ratio. The contribution of the relative humidity, type of finishing material for the concrete surface, and the substitution level of supplementary cementitious materials to the CO 2 diffusion coefficient in concrete was reflected using various correction factors. The following parameters varying with the recycling scenario were also considered: the carbonatable surface area of concrete crusher-runs and underground phenomena of the decreased CO 2 diffusion coefficient and increased CO 2 concentration. Based on the developed procedure, a case study was conducted for an apartment building with a principal wall system and an office building with a Rahmen system, with the aim of examining the CO 2 uptake of each structural element under different exposure environments during the service life and recycling of the building. As input data necessary for the case study, data collected from actual surveys conducted in 2012 in South Korea were used, which included data on the surrounding environments, lifecycle inventory database, life expectancy of structures, and recycling activity scenario. Ultimately, the CO 2 uptake of concrete during a 100-year lifecycle (life expectancy of 40 years and recycling span of 60 years) was estimated to be 15.5%–17% of the CO 2 emissions from concrete production, which roughly corresponds to 18%–21% of the CO 2 emissions from the production of ordinary Portland cement. - Highlights: • CO 2 uptake assessment approach owing to the

  4. Supercritical CO2 uptake by nonswelling phyllosilicates.

    Science.gov (United States)

    Wan, Jiamin; Tokunaga, Tetsu K; Ashby, Paul D; Kim, Yongman; Voltolini, Marco; Gilbert, Benjamin; DePaolo, Donald J

    2018-01-30

    Interactions between supercritical (sc) CO 2 and minerals are important when CO 2 is injected into geologic formations for storage and as working fluids for enhanced oil recovery, hydraulic fracturing, and geothermal energy extraction. It has previously been shown that at the elevated pressures and temperatures of the deep subsurface, scCO 2 alters smectites (typical swelling phyllosilicates). However, less is known about the effects of scCO 2 on nonswelling phyllosilicates (illite and muscovite), despite the fact that the latter are the dominant clay minerals in deep subsurface shales and mudstones. Our studies conducted by using single crystals, combining reaction (incubation with scCO 2 ), visualization [atomic force microscopy (AFM)], and quantifications (AFM, X-ray photoelectron spectroscopy, X-ray diffraction, and off-gassing measurements) revealed unexpectedly high CO 2 uptake that far exceeded its macroscopic surface area. Results from different methods collectively suggest that CO 2 partially entered the muscovite interlayers, although the pathways remain to be determined. We hypothesize that preferential dissolution at weaker surface defects and frayed edges allows CO 2 to enter the interlayers under elevated pressure and temperature, rather than by diffusing solely from edges deeply into interlayers. This unexpected uptake of CO 2 , can increase CO 2 storage capacity by up to ∼30% relative to the capacity associated with residual trapping in a 0.2-porosity sandstone reservoir containing up to 18 mass % of illite/muscovite. This excess CO 2 uptake constitutes a previously unrecognized potential trapping mechanism. Copyright © 2018 the Author(s). Published by PNAS.

  5. Does Elevated CO2 Alter Silica Uptake in Trees?

    Directory of Open Access Journals (Sweden)

    Robinson W. Fulweiler

    2015-01-01

    Full Text Available Human activities have greatly altered global carbon (C and N (N cycling. In fact, atmospheric concentrations of carbon dioxide (CO2 have increased 40% over the last century and the amount of N cycling in the biosphere has more than doubled. In an effort to understand how plants will respond to continued global carbon dioxide fertilization, long-term free-air CO2 enrichment (FACE experiments have been conducted at sites around the globe. Here we examine how atmospheric CO2 enrichment and N fertilization affects the uptake of silicon (Si in the Duke Forest, North Carolina, a stand dominated by Pinus taeda (loblolly pine, and five hardwood species. Specifically, we measured foliar biogenic silica (BSi concentrations in five deciduous and one coniferous species across three treatments: CO2 enrichment, N enrichment, and N and CO2 enrichment. We found no consistent trends in foliar Si concentration under elevated CO2, N fertilization, or combined elevated CO2 and N fertilization. However, two-thirds of the tree species studied here have Si foliar concentrations greater than well-known Si accumulators, such as grasses. Based on net primary production values and aboveground Si concentrations in these trees, we calculated forest Si uptake rates under control and elevated CO2 concentrations. Due largely to increased primary production, elevated CO2 enhanced the magnitude of Si uptake between 20% and 26%, likely intensifying the terrestrial silica pump. This uptake of Si by forests has important implications for Si export from terrestrial systems, with the potential to impact C sequestration and higher trophic levels in downstream ecosystems.

  6. Regional impacts of climate change and atmospheric CO2 on future ocean carbon uptake: a multi model linear feedback analysis

    International Nuclear Information System (INIS)

    Roy, Tilla; Bopp, Laurent; Gehlen, Marion; Cadule, Patricia; Schneider, Birgit; Frolicher, Thomas L.; Segschneider, Joachim; Tjiputra, Jerry; Heinze, Christoph; Joos, Fortunat

    2011-01-01

    The increase in atmospheric CO 2 over this century depends on the evolution of the oceanic air-sea CO 2 uptake, which will be driven by the combined response to rising atmospheric CO 2 itself and climate change. Here, the future oceanic CO 2 uptake is simulated using an ensemble of coupled climate-carbon cycle models. The models are driven by CO 2 emissions from historical data and the Special Report on Emissions Scenarios (SRES) A2 high-emission scenario. A linear feedback analysis successfully separates the regional future (2010-2100) oceanic CO 2 uptake into a CO 2 -induced component, due to rising atmospheric CO 2 concentrations, and a climate-induced component, due to global warming. The models capture the observation based magnitude and distribution of anthropogenic CO 2 uptake. The distributions of the climate-induced component are broadly consistent between the models, with reduced CO 2 uptake in the sub polar Southern Ocean and the equatorial regions, owing to decreased CO 2 solubility; and reduced CO 2 uptake in the mid-latitudes, owing to decreased CO 2 solubility and increased vertical stratification. The magnitude of the climate-induced component is sensitive to local warming in the southern extra-tropics, to large freshwater fluxes in the extra-tropical North Atlantic Ocean, and to small changes in the CO 2 solubility in the equatorial regions. In key anthropogenic CO 2 uptake regions, the climate-induced component offsets the CO 2 - induced component at a constant proportion up until the end of this century. This amounts to approximately 50% in the northern extra-tropics and 25% in the southern extra-tropics and equatorial regions. Consequently, the detection of climate change impacts on anthropogenic CO 2 uptake may be difficult without monitoring additional tracers, such as oxygen. (authors)

  7. Regional impacts of climate change and atmospheric CO2 on future ocean carbon uptake: a multi model linear feedback analysis

    International Nuclear Information System (INIS)

    Roy, Tilla; Bopp, Laurent; Gehlen, Marion; Cadule, Patricia

    2011-01-01

    The increase in atmospheric CO 2 over this century depends on the evolution of the oceanic air-sea CO 2 uptake, which will be driven by the combined response to rising atmospheric CO 2 itself and climate change. Here, the future oceanic CO 2 uptake is simulated using an ensemble of coupled climate-carbon cycle models. The models are driven by CO 2 emissions from historical data and the Special Report on Emissions Scenarios (SRES) A2 high-emission scenario. A linear feedback analysis successfully separates the regional future (2010-2100) oceanic CO 2 uptake into a CO 2 -induced component, due to rising atmospheric CO 2 concentrations, and a climate-induced component, due to global warming. The models capture the observation based magnitude and distribution of anthropogenic CO 2 uptake. The distributions of the climate-induced component are broadly consistent between the models, with reduced CO 2 uptake in the sub-polar Southern Ocean and the equatorial regions, owing to decreased CO 2 solubility; and reduced CO 2 uptake in the mid latitudes, owing to decreased CO 2 solubility and increased vertical stratification. The magnitude of the climate-induced component is sensitive to local warming in the southern extra tropics, to large freshwater fluxes in the extra tropical North Atlantic Ocean, and to small changes in the CO 2 solubility in the equatorial regions. In key anthropogenic CO 2 uptake regions, the climate-induced component offsets the CO 2 - induced component at a constant proportion up until the end of this century. This amounts to approximately 50% in the northern extra tropics and 25% in the southern extra tropics and equatorial regions. Consequently, the detection of climate change impacts on anthropogenic CO 2 uptake may be difficult without monitoring additional tracers, such as oxygen. (authors)

  8. Impact of atmospheric and terrestrial CO2 feedbacks on fertilization-induced marine carbon uptake

    Science.gov (United States)

    Oschlies, A.

    2009-08-01

    The sensitivity of oceanic CO2 uptake to alterations in the marine biological carbon pump, such as brought about by natural or purposeful ocean fertilization, has repeatedly been investigated by studies employing numerical biogeochemical ocean models. It is shown here that the results of such ocean-centered studies are very sensitive to the assumption made about the response of the carbon reservoirs on the atmospheric side of the sea surface. Assumptions made include prescribed atmospheric pCO2, an interactive atmospheric CO2 pool exchanging carbon with the ocean but not with the terrestrial biosphere, and an interactive atmosphere that exchanges carbon with both oceanic and terrestrial carbon pools. The impact of these assumptions on simulated annual to millennial oceanic carbon uptake is investigated for a hypothetical increase in the C:N ratio of the biological pump and for an idealized enhancement of phytoplankton growth. Compared to simulations with interactive atmosphere, using prescribed atmospheric pCO2 overestimates the sensitivity of the oceanic CO2 uptake to changes in the biological pump, by about 2%, 25%, 100%, and >500% on annual, decadal, centennial, and millennial timescales, respectively. The smaller efficiency of the oceanic carbon uptake under an interactive atmosphere is due to the back flux of CO2 that occurs when atmospheric CO2 is reduced. Adding an interactive terrestrial carbon pool to the atmosphere-ocean model system has a small effect on annual timescales, but increases the simulated fertilization-induced oceanic carbon uptake by about 4%, 50%, and 100% on decadal, centennial, and millennial timescales, respectively, for pCO2 sensitivities of the terrestrial carbon storage in the middle range of the C4MIP models (Friedlingstein et al., 2006). For such sensitivities, a substantial fraction of oceanic carbon uptake induced by natural or purposeful ocean fertilization originates, on timescales longer than decades, not from the atmosphere

  9. CO2: EDF's competitiveness is due to nuclear power

    International Nuclear Information System (INIS)

    Anon.

    2003-01-01

    The CO 2 emissions of EDF group (EDF-France + EDF-energy (UK) + Hidrocantabrico (Spain) + EnBW (Germany)) soared by 53% in 2002 which is due to the purchase of british and spanish electricity sub-companies using fossil energies. Despite this sharp increase EDF remains one of the most competitive electricity companies in Europe concerning greenhouse gas emissions. EDF group is the first electricity company in Europe, it generates 22% of the electricity produced in E.U and contributes to CO 2 emissions with a rate of 101 Kg CO 2 /MWh which 3 times less than the average rate of 20 other European companies (358 Kg CO 2 /MWh). This result is due to the large part of nuclear power in the French energy mix. The best electricity companies as far as CO 2 emissions are concerned are Statkraft (Norway) with 0 Kg CO 2 /MWh (100% hydrology) and British-energy (U.K) with 75 Kg CO 2 /MWh (75% nuclear power). At the other end we have the DEI company (Greece) with 863 Kg CO 2 /MWh (100% lignite). (A.C.)

  10. Simulated Impact of Glacial Runoff on CO2 Uptake in the Gulf of Alaska

    Science.gov (United States)

    Pilcher, Darren J.; Siedlecki, Samantha A.; Hermann, Albert J.; Coyle, Kenneth O.; Mathis, Jeremy T.; Evans, Wiley

    2018-01-01

    The Gulf of Alaska (GOA) receives substantial summer freshwater runoff from glacial meltwater. The alkalinity of this runoff is highly dependent on the glacial source and can modify the coastal carbon cycle. We use a regional ocean biogeochemical model to simulate CO2 uptake in the GOA under different alkalinity-loading scenarios. The GOA is identified as a current net sink of carbon, though low-alkalinity tidewater glacial runoff suppresses summer coastal carbon uptake. Our model shows that increasing the alkalinity generates an increase in annual CO2 uptake of 1.9-2.7 TgC/yr. This transition is comparable to a projected change in glacial runoff composition (i.e., from tidewater to land-terminating) due to continued climate warming. Our results demonstrate an important local carbon-climate feedback that can significantly increase coastal carbon uptake via enhanced air-sea exchange, with potential implications to the coastal ecosystems in glaciated areas around the world.

  11. Seasonal climate change patterns due to cumulative CO2 emissions

    Science.gov (United States)

    Partanen, Antti-Ilari; Leduc, Martin; Damon Matthews, H.

    2017-07-01

    Cumulative CO2 emissions are near linearly related to both global and regional changes in annual-mean surface temperature. These relationships are known as the transient climate response to cumulative CO2 emissions (TCRE) and the regional TCRE (RTCRE), and have been shown to remain approximately constant over a wide range of cumulative emissions. Here, we assessed how well this relationship holds for seasonal patterns of temperature change, as well as for annual-mean and seasonal precipitation patterns. We analyzed an idealized scenario with CO2 concentration growing at an annual rate of 1% using data from 12 Earth system models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Seasonal RTCRE values for temperature varied considerably, with the highest seasonal variation evident in the Arctic, where RTCRE was about 5.5 °C per Tt C for boreal winter and about 2.0 °C per Tt C for boreal summer. Also the precipitation response in the Arctic during boreal winter was stronger than during other seasons. We found that emission-normalized seasonal patterns of temperature change were relatively robust with respect to time, though they were sub-linear with respect to emissions particularly near the Arctic. Moreover, RTCRE patterns for precipitation could not be quantified robustly due to the large internal variability of precipitation. Our results suggest that cumulative CO2 emissions are a useful metric to predict regional and seasonal changes in precipitation and temperature. This extension of the TCRE framework to seasonal and regional climate change is helpful for communicating the link between emissions and climate change to policy-makers and the general public, and is well-suited for impact studies that could make use of estimated regional-scale climate changes that are consistent with the carbon budgets associated with global temperature targets.

  12. Impact on CO2 Uptake of MWCNT after Acid Treatment Study

    Directory of Open Access Journals (Sweden)

    Michal Zgrzebnicki

    2017-01-01

    Full Text Available Greenhouse effect is responsible for keeping average temperature of Earth’s atmosphere at level of about 288 K. Its intensification leads to warming of our planet and may contribute to adverse changes in the environment. The most important pollution intensifying greenhouse effect is anthropogenic carbon dioxide. This particular gas absorbs secondary infrared radiation, which in the end leads to an increase of average temperature of Earth’s atmosphere. Main source of CO2 is burning of fossil fuels, like oil, natural gas, and coal. Therefore, to reduce its emission, a special CO2 capture and storage technology is required. Carbonaceous materials are promising materials for CO2 sorbents. Thus multiwalled carbon nanotubes, due to the lack of impurities like ash in activated carbons, were chosen as a model material for investigation of acid treatment impact on CO2 uptake. Remarkable 43% enhancement of CO2 sorption capacity was achieved at 273 K and relative pressure of 0.95. Samples were also thoroughly characterized in terms of texture (specific surface area measurement, transmission electron microscope and chemical composition (X-ray photoelectron spectroscopy.

  13. The role of ocean transport in the uptake of anthropogenic CO2

    Directory of Open Access Journals (Sweden)

    I. Totterdell

    2009-03-01

    Full Text Available We compare modeled oceanic carbon uptake in response to pulse CO2 emissions using a suite of global ocean models and Earth system models. In response to a CO2 pulse emission of 590 Pg C (corresponding to an instantaneous doubling of atmospheric CO2 from 278 to 556 ppm, the fraction of CO2 emitted that is absorbed by the ocean is: 37±8%, 56±10%, and 81±4% (model mean ±2σ in year 30, 100, and 1000 after the emission pulse, respectively. Modeled oceanic uptake of pulse CO2 on timescales from decades to about a century is strongly correlated with simulated present-day uptake of chlorofluorocarbons (CFCs and CO2 across all models, while the amount of pulse CO2 absorbed by the ocean from a century to a millennium is strongly correlated with modeled radiocarbon in the deep Southern and Pacific Ocean. However, restricting the analysis to models that are capable of reproducing observations within uncertainty, the correlation is generally much weaker. The rates of surface-to-deep ocean transport are determined for individual models from the instantaneous doubling CO2 simulations, and they are used to calculate oceanic CO2 uptake in response to pulse CO2 emissions of different sizes pulses of 1000 and 5000 Pg C. These results are compared with simulated oceanic uptake of CO2 by a number of models simulations with the coupling of climate-ocean carbon cycle and without it. This comparison demonstrates that the impact of different ocean transport rates across models on oceanic uptake of anthropogenic CO2 is of similar magnitude as that of climate-carbon cycle feedbacks in a single model, emphasizing the important role of ocean transport in the uptake of anthropogenic CO2.

  14. The relationship between transpiration and nutrient uptake in wheat changes under elevated atmospheric CO2.

    Science.gov (United States)

    Houshmandfar, Alireza; Fitzgerald, Glenn J; O'Leary, Garry; Tausz-Posch, Sabine; Fletcher, Andrew; Tausz, Michael

    2017-12-04

    The impact of elevated [CO 2 ] (e[CO 2 ]) on crops often includes a decrease in their nutrient concentrations where reduced transpiration-driven mass flow of nutrients has been suggested to play a role. We used two independent approaches, a free-air CO 2 enrichment (FACE) experiment in the South Eastern wheat belt of Australia and a simulation study employing the agricultural production systems simulator (APSIM), to show that transpiration (mm) and nutrient uptake (g m -2 ) of nitrogen (N), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg) and manganese (Mn) in wheat are correlated under e[CO 2 ], but that nutrient uptake per unit water transpired is higher under e[CO 2 ] than under ambient [CO 2 ] (a[CO 2 ]). This result suggests that transpiration-driven mass flow of nutrients contributes to decreases in nutrient concentrations under e[CO 2 ], but cannot solely explain the overall decline. © 2017 Scandinavian Plant Physiology Society.

  15. CO2 uptake capacity of coal fly ash

    DEFF Research Database (Denmark)

    Mazzella, Alessandro; Errico, Massimiliano; Spiga, Daniela

    2016-01-01

    Coal ashes are normally considered as a waste obtained by the coal combustion in thermal power plants. Their utilization inside the site where are produced represents an important example of sustainable process integration. The present study was performed to evaluate the application of a gas......-solid carbonation treatment on coal fly ash in order to assess the potential of the process in terms of sequestration of CO2 as well as its influence on the leaching behavior of metals and soluble salts. Laboratory tests, performed under different pressure and temperature conditions, showed that in the pressure......% corresponding to a maximum carbonation efficiency of 74%, estimated on the basis of the initial CaO content. The high degree of ash carbonation achieved in the present research, which was conducted under mild conditions, without add of water and without stirring, showed the potential use of coal fly ash in CO2...

  16. Drier summers cancel out the CO2 uptake enhancement induced by warmer springs.

    Science.gov (United States)

    Angert, A; Biraud, S; Bonfils, C; Henning, C C; Buermann, W; Pinzon, J; Tucker, C J; Fung, I

    2005-08-02

    An increase in photosynthetic activity of the northern hemisphere terrestrial vegetation, as derived from satellite observations, has been reported in previous studies. The amplitude of the seasonal cycle of the annually detrended atmospheric CO(2) in the northern hemisphere (an indicator of biospheric activity) also increased during that period. We found, by analyzing the annually detrended CO(2) record by season, that early summer (June) CO(2) concentrations indeed decreased from 1985 to 1991, and they have continued to decrease from 1994 up to 2002. This decrease indicates accelerating springtime net CO(2) uptake. However, the CO(2) minimum concentration in late summer (an indicator of net growing-season uptake) showed no positive trend since 1994, indicating that lower net CO(2) uptake during summer cancelled out the enhanced uptake during spring. Using a recent satellite normalized difference vegetation index data set and climate data, we show that this lower summer uptake is probably the result of hotter and drier summers in both mid and high latitudes, demonstrating that a warming climate does not necessarily lead to higher CO(2) growing-season uptake, even in high-latitude ecosystems that are considered to be temperature limited.

  17. On the relations between the oceanic uptake of CO2 and its carbon isotopes

    International Nuclear Information System (INIS)

    Heimann, M.; Maier-Reimer, E.

    1994-01-01

    The recent proposals to estimate the oceanic uptake of CO 2 by monitoring the oceanic change in 13 C/ 12 C isotope ratio or the air-sea 13 C/ 12 C isotopic disequilibrium is reviewed. Because the history of atmospheric CO 2 and 13 CO 2 since preindustrial times is almost the same, the oceanic penetration depth of both tracers must be the same. This dynamic constraint permits the establishment of yet a third method to estimate the global ocean uptake of CO 2 from 13 C measurements. Using available observations in conjunction with canonical values for the global carbon cycle parameters the three methods yield inconsistent oceanic CO 2 uptake rates for the time period 1970-1990, ranging from 0 to over 3 GtC year -1 . However, uncertainties in the available carbon cycle data must be taken into account. Using a non-linear estimation procedure, a consistent scenario with an oceanic CO 2 uptake rate of 2.2±0.8 GtC year -1 can be established. The method also permits an investigation of the sensitivities of the different approaches. An analysis of the results of two three-dimensional simulations with the Hamburg Model of the Oceanic Carbon Cycle shows that the 13 C isotope indeed tracks the oceanic penetration of anthropogenic CO 2 . Because of its different time history, bomb produced radiocarbon, as measured at the time of GEOSECS, correlates much less well to excess carbon. (orig.)

  18. Rain events decrease boreal peatland net CO2 uptake through reduced light availability.

    Science.gov (United States)

    Nijp, Jelmer J; Limpens, Juul; Metselaar, Klaas; Peichl, Matthias; Nilsson, Mats B; van der Zee, Sjoerd E A T M; Berendse, Frank

    2015-06-01

    Boreal peatlands store large amounts of carbon, reflecting their important role in the global carbon cycle. The short-term exchange and the long-term storage of atmospheric carbon dioxide (CO2 ) in these ecosystems are closely associated with the permanently wet surface conditions and are susceptible to drought. Especially, the single most important peat forming plant genus, Sphagnum, depends heavily on surface wetness for its primary production. Changes in rainfall patterns are expected to affect surface wetness, but how this transient rewetting affects net ecosystem exchange of CO2 (NEE) remains unknown. This study explores how the timing and characteristics of rain events during photosynthetic active periods, that is daytime, affect peatland NEE and whether rain event associated changes in environmental conditions modify this response (e.g. water table, radiation, vapour pressure deficit, temperature). We analysed an 11-year time series of half-hourly eddy covariance and meteorological measurements from Degerö Stormyr, a boreal peatland in northern Sweden. Our results show that daytime rain events systematically decreased the sink strength of peatlands for atmospheric CO2 . The decrease was best explained by rain associated reduction in light, rather than by rain characteristics or drought length. An average daytime growing season rain event reduced net ecosystem CO2 uptake by 0.23-0.54 gC m(-2) . On an annual basis, this reduction of net CO2 uptake corresponds to 24% of the annual net CO2 uptake (NEE) of the study site, equivalent to a 4.4% reduction of gross primary production (GPP) during the growing season. We conclude that reduced light availability associated with rain events is more important in explaining the NEE response to rain events than rain characteristics and changes in water availability. This suggests that peatland CO2 uptake is highly sensitive to changes in cloud cover formation and to altered rainfall regimes, a process hitherto largely

  19. Southern hemisphere ocean CO2 uptake: reconciling atmospheric and oceanic estimates

    International Nuclear Information System (INIS)

    Roy, T.; Matear, R.; Rayner, P.; Francey, R.

    2003-01-01

    Using an atmospheric inversion model we investigate the southern hemisphere ocean CO 2 uptake. From sensitivity studies that varied both the initial ocean flux distribution and the atmospheric data used in the inversion, our inversion predicted a total (ocean and land) uptake of 1.65-1.90 Gt C/yr. We assess the consistency between the mean southern hemisphere ocean uptake predicted by an atmospheric inversion model for the 1991-1997 period and the T99 ocean flux estimate based on observed pCO 2 in Takahashi et al. (2002; Deep-Sea Res II, 49, 1601-1622). The inversion can not match the large 1.8 Gt C/yr southern extratropical (20-90 deg S) uptake of the T99 ocean flux estimate without producing either unreasonable land fluxes in the southern mid-latitudes or by increasing the mismatches between observed and simulated atmospheric CO 2 data. The southern extratropical uptake is redistributed between the mid and high latitudes. Our results suggest that the T99 estimate of the Southern Ocean uptake south of 50 deg S is too large, and that the discrepancy reflects the inadequate representation of wintertime conditions in the T99 estimate

  20. The declining uptake rate of atmospheric CO2 by land and ocean sinks

    Directory of Open Access Journals (Sweden)

    M. R. Raupach

    2014-07-01

    Full Text Available Through 1959–2012, an airborne fraction (AF of 0.44 of total anthropogenic CO2 emissions remained in the atmosphere, with the rest being taken up by land and ocean CO2 sinks. Understanding of this uptake is critical because it greatly alleviates the emissions reductions required for climate mitigation, and also reduces the risks and damages that adaptation has to embrace. An observable quantity that reflects sink properties more directly than the AF is the CO2 sink rate (kS, the combined land–ocean CO2 sink flux per unit excess atmospheric CO2 above preindustrial levels. Here we show from observations that kS declined over 1959–2012 by a factor of about 1 / 3, implying that CO2 sinks increased more slowly than excess CO2. Using a carbon–climate model, we attribute the decline in kS to four mechanisms: slower-than-exponential CO2 emissions growth (~ 35% of the trend, volcanic eruptions (~ 25%, sink responses to climate change (~ 20%, and nonlinear responses to increasing CO2, mainly oceanic (~ 20%. The first of these mechanisms is associated purely with the trajectory of extrinsic forcing, and the last two with intrinsic, feedback responses of sink processes to changes in climate and atmospheric CO2. Our results suggest that the effects of these intrinsic, nonlinear responses are already detectable in the global carbon cycle. Although continuing future decreases in kS will occur under all plausible CO2 emission scenarios, the rate of decline varies between scenarios in non-intuitive ways because extrinsic and intrinsic mechanisms respond in opposite ways to changes in emissions: extrinsic mechanisms cause kS to decline more strongly with increasing mitigation, while intrinsic mechanisms cause kS to decline more strongly under high-emission, low-mitigation scenarios as the carbon–climate system is perturbed further from a near-linear regime.

  1. The declining uptake rate of atmospheric CO2 by land and ocean sinks

    International Nuclear Information System (INIS)

    Raupach, M.R.; Gloor, M.; Sarmiento, J.L.; Gasser, T.

    2014-01-01

    Through 1959-2012, an airborne fraction (AF) of 0.44 of total anthropogenic CO 2 emissions remained in the atmosphere, with the rest being taken up by land and ocean CO 2 sinks. Understanding of this uptake is critical because it greatly alleviates the emissions reductions required for climate mitigation, and also reduces the risks and damages that adaptation has to embrace. An observable quantity that reflects sink properties more directly than the AF is the CO 2 sink rate (k S ), the combined land-ocean CO 2 sink flux per unit excess atmospheric CO 2 above pre industrial levels. Here we show from observations that k S declined over 1959-2012 by a factor of about 1/3, implying that CO 2 sinks increased more slowly than excess CO 2 . Using a carbon-climate model, we attribute the decline in k S to four mechanisms: slower-than-exponential CO 2 emissions growth (35% of the trend), volcanic eruptions (25 %), sink responses to climate change (20 %), and nonlinear responses to increasing CO 2 , mainly oceanic (20 %). The first of these mechanisms is associated purely with the trajectory of extrinsic forcing, and the last two with intrinsic, feedback responses of sink processes to changes in climate and atmospheric CO 2 . Our results suggest that the effects of these intrinsic, nonlinear responses are already detectable in the global carbon cycle. Although continuing future decreases in k S will occur under all plausible CO 2 emission scenarios, the rate of decline varies between scenarios in non intuitive ways because extrinsic and intrinsic mechanisms respond in opposite ways to changes in emissions: extrinsic mechanisms cause k S to decline more strongly with increasing mitigation, while intrinsic mechanisms cause k S to decline more strongly under high-emission, low-mitigation scenarios as the carbon-climate system is perturbed further from a near-linear regime. (authors)

  2. Effect of CO2 Enrichment on the Growth and Nutrient Uptake of Tomato Seedlings

    Institute of Scientific and Technical Information of China (English)

    LI Juan; ZHOU Jian-Min; DUAN Zeng-Qiang; DU Chang-Wen; WANG Huo-Yan

    2007-01-01

    Exposing tomato seedlings to elevated CO2 concentrations may have potentially profound impacts on the tomato yield and quality. A growth chamber experiment was designed to estimate how different nutrient concentrations influenced the effect of elevated CO2 on the growth and nutrient uptake of tomato seedlings. Tomato (Hezuo 906) was grown in pots placed in controlled growth chambers and was subjected to ambient or elevated CO2 (360 or 720 μL L-1), and four nutrient solutions of different strengths (1/2-, 1/4-, 1/8-, and 1/16-strength Japan Yamazaki nutrient solutions) in a completely randomized design. The results indicated that some agricultural characteristics of the tomato seedlings such as the plant height, stem thickness, total dry and fresh weights of the leaves, stems and roots, the G value (G value = total plant dry weight/seedling age),and the seedling vigor index (seedling vigor index = stem thickness/(plant height × total plant dry weight) increased with the elevated CO2, and the increases were strongly dependent on the nutrient solution concentrations, being greater with higher nutrient solution concentrations. The elevated CO2 did not alter the ratio of root to shoot. The total N, P, K, and C absorbed from all the solutions except P in the 1/8- and 1/16-strength nutrient solutions increased in the elevated CO2 treatment. These results demonstrate that the nutrient demands of the tomato seedlings increased at elevated CO2 concentrations.

  3. Net uptake of atmospheric CO2 by coastal submerged aquatic vegetation

    Science.gov (United States)

    Tokoro, Tatsuki; Hosokawa, Shinya; Miyoshi, Eiichi; Tada, Kazufumi; Watanabe, Kenta; Montani, Shigeru; Kayanne, Hajime; Kuwae, Tomohiro

    2014-01-01

    ‘Blue Carbon’, which is carbon captured by marine living organisms, has recently been highlighted as a new option for climate change mitigation initiatives. In particular, coastal ecosystems have been recognized as significant carbon stocks because of their high burial rates and long-term sequestration of carbon. However, the direct contribution of Blue Carbon to the uptake of atmospheric CO2 through air-sea gas exchange remains unclear. We performed in situ measurements of carbon flows, including air-sea CO2 fluxes, dissolved inorganic carbon changes, net ecosystem production, and carbon burial rates in the boreal (Furen), temperate (Kurihama), and subtropical (Fukido) seagrass meadows of Japan from 2010 to 2013. In particular, the air-sea CO2 flux was measured using three methods: the bulk formula method, the floating chamber method, and the eddy covariance method. Our empirical results show that submerged autotrophic vegetation in shallow coastal waters can be functionally a sink for atmospheric CO2. This finding is contrary to the conventional perception that most near-shore ecosystems are sources of atmospheric CO2. The key factor determining whether or not coastal ecosystems directly decrease the concentration of atmospheric CO2 may be net ecosystem production. This study thus identifies a new ecosystem function of coastal vegetated systems; they are direct sinks of atmospheric CO2. PMID:24623530

  4. The effect of light supply on microalgal growth, CO2 uptake and nutrient removal from wastewater

    International Nuclear Information System (INIS)

    Gonçalves, A.L.; Simões, M.; Pires, J.C.M.

    2014-01-01

    Highlights: • Effect of irradiance and light:dark ratio on microalgal growth was analysed. • Microalgal growth, CO 2 capture, nitrogen and phosphorus uptake were evaluated. • Higher irradiances and light periods supported higher growth and CO 2 uptake rates. • All the studied microalgal strains have shown high nitrogen removal efficiencies. • The highest phosphorus removal efficiency was 67.6%. - Abstract: Microalgal based biofuels have been reported as an attractive alternative for fossil fuels, since they constitute a renewable energy source that reduces greenhouse gas emissions to the atmosphere. However, producing biofuels from microalgae is still not economically viable. Therefore, the integration of biofuel production with other microalgal applications, such as CO 2 capture and nutrient removal from wastewaters, would reduce the microalgal production costs (and the environmental impact of cultures), increasing the economic viability of the whole process. Additionally, producing biofuels from microalgae strongly depends on microalgal strain and culture conditions. This study evaluates the effect of culture conditions, namely light irradiance (36, 60, 120 and 180 μE m −2 s −1 ) and light:dark ratio (10:14, 14:10 and 24:0), on microalgal growth, atmospheric CO 2 uptake and nutrient (nitrogen and phosphorous) removal from culture medium. Four different microalgal strains, Chlorella vulgaris, Pseudokirchneriella subcapitata, Synechocystis salina and Microcystis aeruginosa, were studied to ascertain the most advantageous regarding the referred applications. This study has shown that higher light irradiance values and light periods resulted in higher specific growth rates and CO 2 uptake rates. C. vulgaris presented the highest specific growth rate and CO 2 uptake rate: 1.190 ± 0.041 d −1 and 0.471 ± 0.047 g CO2 L −1 d −1 , respectively. All the strains have shown high nitrogen removal efficiencies, reaching 100% removal percentages in

  5. Arctic Ocean CO2 uptake: an improved multiyear estimate of the air-sea CO2 flux incorporating chlorophyll a concentrations

    Science.gov (United States)

    Yasunaka, Sayaka; Siswanto, Eko; Olsen, Are; Hoppema, Mario; Watanabe, Eiji; Fransson, Agneta; Chierici, Melissa; Murata, Akihiko; Lauvset, Siv K.; Wanninkhof, Rik; Takahashi, Taro; Kosugi, Naohiro; Omar, Abdirahman M.; van Heuven, Steven; Mathis, Jeremy T.

    2018-03-01

    We estimated monthly air-sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014. This was done by mapping partial pressure of CO2 in the surface water (pCO2w) using a self-organizing map (SOM) technique incorporating chlorophyll a concentration (Chl a), sea surface temperature, sea surface salinity, sea ice concentration, atmospheric CO2 mixing ratio, and geographical position. We applied new algorithms for extracting Chl a from satellite remote sensing reflectance with close examination of uncertainty of the obtained Chl a values. The overall relationship between pCO2w and Chl a was negative, whereas the relationship varied among seasons and regions. The addition of Chl a as a parameter in the SOM process enabled us to improve the estimate of pCO2w, particularly via better representation of its decline in spring, which resulted from biologically mediated pCO2w reduction. As a result of the inclusion of Chl a, the uncertainty in the CO2 flux estimate was reduced, with a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C yr-1. Seasonal to interannual variation in the CO2 influx was also calculated.

  6. Young Daughter Cladodes Affect CO2 Uptake by Mother Cladodes of Opuntia ficus-indica

    Science.gov (United States)

    PIMIENTA-BARRIOS, EULOGIO; ZAÑUDO-HERNANDEZ, JULIA; ROSAS-ESPINOZA, VERONICA C.; VALENZUELA-TAPIA, AMARANTA; NOBEL, PARK S.

    2004-01-01

    • Background and Aims Drought damages cultivated C3, C4 and CAM plants in the semi-arid lands of central Mexico. Drought damage to Opuntia is common when mother cladodes, planted during the dry spring season, develop young daughter cladodes that behave like C3 plants, with daytime stomatal opening and water loss. In contrast, wild Opuntia are less affected because daughter cladodes do not develop on them under extreme drought conditions. The main objective of this work is to evaluate the effects of the number of daughter cladodes on gas exchange parameters of mother cladodes of Opuntia ficus-indica exposed to varying soil water contents. • Methods Rates of net CO2 uptake, stomatal conductance, intercellular CO2 concentration, chlorophyll content and relative water content were measured in mature mother cladodes with a variable number of daughter cladodes growing in spring under dry and wet conditions. • Key Results Daily carbon gain by mother cladodes was reduced as the number of daughter cladodes increased to eight, especially during drought. This was accompanied by decreased mother cladode relative water content, suggesting movement of water from mother to daughter cladodes. CO2 assimilation was most affected in phase IV of CAM (late afternoon net CO2 uptake) by the combined effects of daughter cladodes and drought. Rainfall raised the soil water content, decreasing the effects of daughter cladodes on net CO2 uptake by mother cladodes. • Conclusions Daughter cladodes significantly hasten the effects of drought on mother cladodes by competition for the water supply and thus decrease daily carbon gain by mother cladodes, mainly by inhibiting phase IV of CAM. PMID:15567805

  7. Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing.

    Science.gov (United States)

    Parazoo, Nicholas C; Arneth, Almut; Pugh, Thomas A M; Smith, Ben; Steiner, Nicholas; Luus, Kristina; Commane, Roisin; Benmergui, Josh; Stofferahn, Eric; Liu, Junjie; Rödenbeck, Christian; Kawa, Randy; Euskirchen, Eugenie; Zona, Donatella; Arndt, Kyle; Oechel, Walt; Miller, Charles

    2018-04-24

    The springtime transition to regional-scale onset of photosynthesis and net ecosystem carbon uptake in boreal and tundra ecosystems are linked to the soil freeze-thaw state. We present evidence from diagnostic and inversion models constrained by satellite fluorescence and airborne CO 2 from 2012 to 2014 indicating the timing and magnitude of spring carbon uptake in Alaska correlates with landscape thaw and ecoregion. Landscape thaw in boreal forests typically occurs in late April (DOY 111 ± 7) with a 29 ± 6 day lag until photosynthetic onset. North Slope tundra thaws 3 weeks later (DOY 133 ± 5) but experiences only a 20 ± 5 day lag until photosynthetic onset. These time lag differences reflect efficient cold season adaptation in tundra shrub and the longer dehardening period for boreal evergreens. Despite the short transition from thaw to photosynthetic onset in tundra, synchrony of tundra respiration with snow melt and landscape thaw delays the transition from net carbon loss (at photosynthetic onset) to net uptake by 13 ± 7 days, thus reducing the tundra net carbon uptake period. Two global CO 2 inversions using a CASA-GFED model prior estimate earlier northern high latitude net carbon uptake compared to our regional inversion, which we attribute to (i) early photosynthetic-onset model prior bias, (ii) inverse method (scaling factor + optimization window), and (iii) sparsity of available Alaskan CO 2 observations. Another global inversion with zero prior estimates the same timing for net carbon uptake as the regional model but smaller seasonal amplitude. The analysis of Alaskan eddy covariance observations confirms regional scale findings for tundra, but indicates that photosynthesis and net carbon uptake occur up to 1 month earlier in evergreens than captured by models or CO 2 inversions, with better correlation to above-freezing air temperature than date of primary thaw. Further collection and analysis of boreal evergreen species over

  8. A Review of Human Health and Ecological Risks due to CO2 Exposure

    Science.gov (United States)

    Hepple, R. P.; Benson, S. M.

    2001-05-01

    Nyos in Cameroon, Mammoth Mountain in California, Dieng Volcanic Complex in Java, Indonesia, and industrial accidents with CO2 fire suppression systems teach that slow leakage rates and effective dilution must be proven to ensure human and environmental safety. Monitoring CO2 levels in occupational settings is done with reliable IR sensors. Remote sensing of low levels of CO2 over long distances cannot be done easily yet, although LIDAR, an airborne laser technique under development, may have good potential. The environmental impacts of elevated CO2 levels on vegetation are being investigated now in free-air CO2 enrichment studies. In general, persistent elevated CO2 levels cause a change in species composition, favoring C3 plants over C4 or CAM. The ecological effects of catastrophic releases are severe but depend upon (a) release rate and amount, (b) surface topography and rate of atmospheric mixing (c) exposure concentrations and duration, (d) the respiratory mechanism of the form of life under discussion, (e) its tolerance for oxygen deprivation, and (f) its ability to maintain homeostatic pH levels. Suppression of root respiration due to elevated soil-gas CO2 concentrations and acidifiction of the root zone are known mechanisms of tree-kill. Soil-gas CO2 in the tree-kill areas at Mammoth Mountain exceeded 20-30% at 15 cm depth. Surface masses of concentrated CO2 probably smother the canopy through oxygen deprivation, but the precise mechanism is not known. Lake Nyos and Mammoth Mountain reveal that catastrophic releases can result in complete dead zones.

  9. CO2 uptake of Opuntia ficus-indica (L. Mill. whole trees and single cladodes, in relation to plant water status and cladode age

    Directory of Open Access Journals (Sweden)

    Giorgia Liguori

    2013-02-01

    Full Text Available Most of net photosynthesis determinations in Opuntia ficus-indica come from measurements on individual cladodes. However, they have limitations when used to scale up to whole canopy gas exchange, because a large variability of carbon assimilation may occur within the canopy, due to, among others, differences in cladode age and intercepted radiation or individual cladode response to abiotic stresses. The aim of this work was to evaluate the application of open gas exchange chambers, simultaneously applied around the whole canopy, to measure net CO2 uptake, continuously over a 24 h period, in single Opuntia ficus-indica (L. Mill. potted trees and in relation with their water status. Net CO2 uptake was also measured for single cladodes differentiated by age. O. ficus-indica trees continued their photosynthetic activity 60 days after the irrigation was stopped, when soil water content was lower than 5%. At this stage, current-year and 1-year-old cladodes had become flaccid but still the daily net CO2 uptake of non-irrigated trees kept the same rate than at the beginning of the experiment, while watered trees had doubled their net CO2 uptake. The highest instantaneous rates and total daily net CO2 uptake for both well-watered and non-irrigated trees occurred 60 days after the onset of the dry period, when maximal instantaneous rates were 11.1 in well-watered trees and 8.4 mol m–2 s–1 in non-irrigated trees. During the drought period, the chlorenchyma fresh weight decreased by 45% and 30%, in 1- and 2-yearold drought cladodes respectively, and marginally increased in currentyear ones (+20%. Net CO2 uptake for 1-year-old and 2-year-old cladodes changed only at highest photosynthetic photon flux density and temperatures, and average seasonal net CO2 uptake of 2-year-old cladodes was 15% lower than for 1-year-old ones. Whole-tree gas exchange measurements applied for the first time to O. ficus-indica indicated that whole cactus pear trees maintain

  10. Role of mesoscale eddies in the global ocean uptake of anthropogenic CO2

    International Nuclear Information System (INIS)

    Zouhair, Lachkar

    2007-02-01

    Mesoscale eddies play a fundamental role in ocean dynamics particularly in the Southern Ocean. Global-scale tracer simulations are typically made at coarse resolution without explicitly modeling eddies. Here we ask what role do eddies play in ocean uptake, storage, and meridional transport of anthropogenic CO 2 , CFC-11 and bomb Δ 14 C. We made global anthropogenic transient tracer simulations in coarse-resolution, ORCA2, and eddy-permitting, ORCA05 and ORCA025, versions of the ocean modelling system NEMO. We focus on the Southern Ocean where tracer air-sea fluxes are largest. Eddies have little effect on bomb Δ 14 C uptake and storage. Yet for CFC-11 and anthropogenic CO 2 , increased eddy activity reduces southern extra-tropical uptake by 28% and 25% respectively, thereby providing better agreement with observations. It is shown that the discrepancies in the equilibration times between the three tracers determine their respective sensitivities to the model horizontal resolution. Applying Gent and McWilliams (1990) (GM) parameterization of eddies in the non-eddying version of the model does improve results, but not enough. An in-depth investigation of the mechanisms by which eddies affect the uptake of the transient tracers shows that including mesoscale eddies leads to an overall reduction in the Antarctic Intermediate Water (AAIW) ventilation, and modifies substantially the spatial distribution of their source regions. This investigation reveals also that the GM parameterization still overestimates the ventilation and the subduction of AAIW in the Indian Ocean where the simulated mixed layer is particularly deep during the winter. This work suggests that most current coarse-resolution models may overestimate the ventilation of AAIW in the Indian sector of the Southern Ocean. This study shows also that the use of the GM parameterization may be of limited utility where mixed layer is relatively deep and confirms the general need for a more adequate

  11. Long-Term Drainage Reduces CO2 Uptake and CH4 Emissions in a Siberian Permafrost Ecosystem

    Science.gov (United States)

    Kittler, Fanny; Heimann, Martin; Kolle, Olaf; Zimov, Nikita; Zimov, Sergei; Göckede, Mathias

    2017-12-01

    Permafrost landscapes in northern high latitudes with their massive organic carbon stocks are an important, poorly known, component of the global carbon cycle. However, in light of future Arctic warming, the sustainability of these carbon pools is uncertain. To a large part, this is due to a limited understanding of the carbon cycle processes because of sparse observations in Arctic permafrost ecosystems. Here we present an eddy covariance data set covering more than 3 years of continuous CO2 and CH4 flux observations within a moist tussock tundra ecosystem near Chersky in north-eastern Siberia. Through parallel observations of a disturbed (drained) area and a control area nearby, we aim to evaluate the long-term effects of a persistently lowered water table on the net vertical carbon exchange budgets and the dominating biogeochemical mechanisms. Persistently drier soils trigger systematic shifts in the tundra ecosystem carbon cycle patterns. Both, uptake rates of CO2 and emissions of CH4 decreased. Year-round measurements emphasize the importance of the non-growing season—in particular the "zero-curtain" period in the fall—to the annual budget. Approximately 60% of the CO2 uptake in the growing season is lost during the cold seasons, while CH4 emissions during the non-growing season account for 30% of the annual budget. Year-to-year variability in temperature conditions during the late growing season was identified as the primary control of the interannual variability observed in the CO2 and CH4 fluxes.

  12. Fungal inoculation and elevated CO2 mediate growth of Lolium mutiforum and Phytolacca americana, metal uptake, and metal bioavailability in metal-contaminated soil: evidence from DGT measurement.

    Science.gov (United States)

    Song, Ningning; Wang, Fangli; Zhang, Changbo; Tang, Shirong; Guo, Junkang; Ju, Xuehai; Smith, Donald L

    2013-01-01

    Fungal inoculation and elevated CO2 may mediate plant growth and uptake of heavy metals, but little evidence from Diffusive Gradients in Thin-films (DGT) measurement has been obtained to characterize the process. Lolium mutiforum and Phytolacca americana were grown at ambient and elevated CO2 on naturally Cd and Pb contaminated soils inoculated with and without Trichoderma asperellum strain C3 or Penicillium chrysogenum strain D4, to investigate plant growth, metal uptake, and metal bioavailability responses. Fungal inoculation increased plant biomass and shoot/root Cd and Pb concentrations. Elevated CO2 significantly increased plants biomass, but decreased Cd and Pb concentrations in shoot/root to various extents, leading to a metal dilution phenomenon. Total Cd and Pb uptake by plants, and DGT-measured Cd and Pb concentrations in rhizosphere soils, were higher in all fungal inoculation and elevated CO2 treatments than control treatments, with the combined treatments having more influence than either treatment alone. Metal dilution phenomenon occurred because the increase in DGT-measured bioavailable metal pools in plant rhizosphere due to elevated CO2 was unable to match the increase in requirement for plant uptake of metals due to plant biomass increase.

  13. CO2 emissions due to energy combustion in the World in 2011

    International Nuclear Information System (INIS)

    Wong, Florine

    2014-01-01

    This publication presents and comments data, graphs and tables which illustrate the evolution of CO 2 emissions in the world (data are given for different countries and regions of the World), and more particularly those due to energy combustion. These emissions increased in 2011. It also discusses the evolution of CO 2 emission intensity with respect to GDP (1 pc decrease in 2011). When studying emission data with respect to the number of inhabitants, it appears that USA are emitting 20 times more CO 2 per inhabitant than Africa

  14. Oceanic uptake of CO2 re-estimated through δ13C in WOCE samples

    International Nuclear Information System (INIS)

    Lerperger, Michael; McNichol, A.P.; Peden, J.; Gagnon, A.R.; Elder, K.L.; Kutschera, W.; Rom, W.; Steier, P.

    2000-01-01

    In addition to 14 C, a large set of δ 13 C data was produced at NOSAMS as part of the World ocean circulation experiment (WOCE). In this paper, a subset of 973 δ 13 C results from 63 stations in the Pacific Ocean was compared to a total number of 219 corresponding results from 12 stations sampled during oceanographic programs in the early 1970s. The data were analyzed in light of recent work to estimate the uptake of CO 2 derived from fossil fuel and biomass burning in the oceans by quantifying the δ 13 C Suess effect in the oceans. In principle, the δ 13 C value of dissolved inorganic carbon (DIC) allows a quantitative estimate of how much of the anthropogenic CO 2 released into the atmosphere is taken up by the oceans, because the δ 13 C of CO 2 derived from organic matter (∼2.7 percent) is significantly different from that of the atmosphere (∼0.8 percent). Our new analysis indicates an apparent discrepancy between the old and the new data sets, possibly caused by a constant offset in δ 13 C values in a subset of the data. A similar offset was reported in an earlier work by Paul Quay et al. for one station that was not included in their final analysis. We present an estimate for this assumed offset based on data from water depths below which little or no change in δ 13 C over time would be expected. Such a correction leads to a significantly reduced estimate of the CO 2 uptake, possibly as low as one half of the amount of 2.1 GtC yr -1 (gigatons carbon per year) estimated previously. The present conclusion is based on a comparison with a relatively small data set from the 70s in the Pacific Ocean. The larger data set collected during the GEOSECS program was not used because of problems reported with the data. This work suggests there may also be problems in comparing non-GEOSECS data from the 1970s to the current data. The calculation of significantly lower uptake estimates based on an offset-related problem appears valid, but the exact figures are

  15. Recent slowdown of atmospheric CO2 amplification due to vegetation-climate feedback over northern lands

    Science.gov (United States)

    Li, Z.; Xia, J.; Ahlström, A.; Rinke, A.; Koven, C.; Hayes, D. J.; Ji, D.; Zhang, G.; Krinner, G.; Chen, G.; Dong, J.; Liang, J.; Moore, J.; Jiang, L.; Yan, L.; Ciais, P.; Peng, S.; Wang, Y.; Xiao, X.; Shi, Z.; McGuire, A. D.; Luo, Y.

    2017-12-01

    The enhanced vegetation growth by climate warming plays a pivotal role in amplifying the seasonal cycle of atmospheric CO2 at northern high latitudes since 1960s1-3. It remains unclear that whether this mechanism is still robust since 1990s, because a paused vegetation growth increase4,5 and weakened temperature control on CO2 uptake6,7 have been detected during this period. Here, based on in-situ atmospheric CO2 concentration records above northern 50o N, we found a slowdown of the atmospheric CO2 amplification from the mid-1990s to mid-2000s. This phenomenon is associated with the pause of vegetation greening trend and slowdown of spring warming. We further showed that both the vegetation greenness and its growing season length are positively correlated to spring but not autumn temperature from 1982 to 2010 over the northern lands. However, the state-of-art terrestrial biosphere models produce positive responses of gross primary productivity to both spring and autumn warming. These findings emphasize the importance of vegetation-climate feedback in shaping the atmospheric CO2 seasonality, and call for an improved carbon-cycle response to non-uniform seasonal warming at high latitudes in current models.

  16. Prediction of the viscosity reduction due to dissolved CO2 of and an elementary approach in the supercritical CO2 assisted continuous particle production of a polyester resin

    NARCIS (Netherlands)

    Nalawade, Sameer P.; Nieborg, Vincent H. J.; Picchioni, Francesco; Janssen, L. P. B. M.

    2006-01-01

    The dissolution of CO2 in a polymer causes plasticization of the polymer and hence, its viscosity is reduced. A model based on the free volume theory has been used for a polyester resin, which shows a considerable reduction in the viscosity due to dissolved M. Therefore, superctitical CO2 has been

  17. Increasing summer net CO2 uptake in high northern ecosystems inferred from atmospheric inversions and comparisons to remote-sensing NDVI

    Directory of Open Access Journals (Sweden)

    L. R. Welp

    2016-07-01

    Full Text Available Warmer temperatures and elevated atmospheric CO2 concentrations over the last several decades have been credited with increasing vegetation activity and photosynthetic uptake of CO2 from the atmosphere in the high northern latitude ecosystems: the boreal forest and arctic tundra. At the same time, soils in the region have been warming, permafrost is melting, fire frequency and severity are increasing, and some regions of the boreal forest are showing signs of stress due to drought or insect disturbance. The recent trends in net carbon balance of these ecosystems, across heterogeneous disturbance patterns, and the future implications of these changes are unclear. Here, we examine CO2 fluxes from northern boreal and tundra regions from 1985 to 2012, estimated from two atmospheric inversions (RIGC and Jena. Both used measured atmospheric CO2 concentrations and wind fields from interannually variable climate reanalysis. In the arctic zone, the latitude region above 60° N excluding Europe (10° W–63° E, neither inversion finds a significant long-term trend in annual CO2 balance. The boreal zone, the latitude region from approximately 50–60° N, again excluding Europe, showed a trend of 8–11 Tg C yr−2 over the common period of validity from 1986 to 2006, resulting in an annual CO2 sink in 2006 that was 170–230 Tg C yr−1 larger than in 1986. This trend appears to continue through 2012 in the Jena inversion as well. In both latitudinal zones, the seasonal amplitude of monthly CO2 fluxes increased due to increased uptake in summer, and in the arctic zone also due to increased fall CO2 release. These findings suggest that the boreal zone has been maintaining and likely increasing CO2 sink strength over this period, despite browning trends in some regions and changes in fire frequency and land use. Meanwhile, the arctic zone shows that increased summer CO2 uptake, consistent with strong greening trends, is offset by

  18. The effects of water management on the CO2 uptake of Sphagnum moss in a reclaimed peatland

    Directory of Open Access Journals (Sweden)

    C.M. Brown

    2017-07-01

    Full Text Available To harvest Sphagnum on a cyclic basis and rapidly accumulate biomass, active water management is necessary. The goal of this study is to determine the hydrological conditions that will maximise CO2 uptake in Sphagnum farming basins following the moss-layer transfer technique. Plot CO2 uptake doubled from the first growing season to the second, but growth was not uniform across the site. Results indicate that the seasonal oscillations in water table (WT position were more important than actual WT position for estimating Sphagnum ground cover and CO2 uptake when the seasonal WT is shallow (< -25 cm. Plots with higher productivity had a WT range (seasonal maximum – minimum less than 15 cm, a WT position which did not fluctuate more than ± 7.5 cm, and a low WT standard deviation. Each basin was a CO2 source during the second growing season, and seasonal modelled NEE ranged from 107.1 to 266.8 g CO2 m-2. Decomposition from the straw mulch accounted for over half of seasonal respiration, and the site is expected to become a CO2 sink as the straw mulch decomposes and moss cover increases. This study highlights the importance of maintaining stable moisture conditions to increase Sphagnum growth and CO2 sink functions.

  19. Increasing efficiency of CO2 uptake by combined land-ocean sink

    Science.gov (United States)

    van Marle, M.; van Wees, D.; Houghton, R. A.; Nassikas, A.; van der Werf, G.

    2017-12-01

    Carbon-climate feedbacks are one of the key uncertainties in predicting future climate change. Such a feedback could originate from carbon sinks losing their efficiency, for example due to saturation of the CO2 fertilization effect or ocean warming. An indirect approach to estimate how the combined land and ocean sink responds to climate change and growing fossil fuel emissions is based on assessing the trends in the airborne fraction of CO2 emissions from fossil fuel and land use change. One key limitation with this approach has been the large uncertainty in quantifying land use change emissions. We have re-assessed those emissions in a more data-driven approach by combining estimates coming from a bookkeeping model with visibility-based land use change emissions available for the Arc of Deforestation and Equatorial Asia, two key regions with large land use change emissions. The advantage of the visibility-based dataset is that the emissions are observation-based and this dataset provides more detailed information about interannual variability than previous estimates. Based on our estimates we provide evidence that land use and land cover change emissions have increased more rapidly than previously thought, implying that the airborne fraction has decreased since the start of CO2 measurements in 1959. This finding is surprising because it means that the combined land and ocean sink has become more efficient while the opposite is expected.

  20. Atmospheric CO2 Observations Reveal Strong Correlation Between Regional Net Biospheric Carbon Uptake and Solar-Induced Chlorophyll Fluorescence

    Science.gov (United States)

    Shiga, Yoichi P.; Tadić, Jovan M.; Qiu, Xuemei; Yadav, Vineet; Andrews, Arlyn E.; Berry, Joseph A.; Michalak, Anna M.

    2018-01-01

    Recent studies have shown the promise of remotely sensed solar-induced chlorophyll fluorescence (SIF) in informing terrestrial carbon exchange, but analyses have been limited to either plot level ( 1 km2) or hemispheric/global ( 108 km2) scales due to the lack of a direct measure of carbon exchange at intermediate scales. Here we use a network of atmospheric CO2 observations over North America to explore the value of SIF for informing net ecosystem exchange (NEE) at regional scales. We find that SIF explains space-time NEE patterns at regional ( 100 km2) scales better than a variety of other vegetation and climate indicators. We further show that incorporating SIF into an atmospheric inversion leads to a spatial redistribution of NEE estimates over North America, with more uptake attributed to agricultural regions and less to needleleaf forests. Our results highlight the synergy of ground-based and spaceborne carbon cycle observations.

  1. Utility of multiple tracer distributions in calibrating models for uptake of anthropogenic CO2 by the ocean thermocline

    International Nuclear Information System (INIS)

    Peng, T.H.; Broecker, W.S.

    1985-01-01

    Two-dimensional thermocline ventilation models for the temperate North Atlantic with differing circulation patterns were calibrated to yield a tritium distribution similar to that observed during the GEOSECS survey. These models were then run for 3 He, bomb-produced 14 C, radiokrypton, and freons. They were also run for the uptake of fossil fuel CO 2 . While the models differ significantly in their ability to match the observed 3 He and 14 C distributions, these differences are not large enough to clearly single out one model as superior. This insensitivity of tracer-to-tracer ratio to model design is reflected by the near identity of the fossil fuel CO 2 uptake by the various models. This result suggests that the uptake of CO 2 by the sea is limited more by the rates of physical mixing within the sea than by gas exchange across the sea surface. If so, then the hope that models employing outcropping isopycnals will enhance the CO 2 uptake by the sea and thereby lead to a narrowing in the gap that exists for anthropogenic CO 2 budgets is not well founded. The interim strategy of using reservoir models calibrated by tracer distributions appears to be sound. 20 references, 19 figures, 5 tables

  2. Herbicide-induced changes in 14CO2 uptake of leaves of some crop and weed species

    International Nuclear Information System (INIS)

    Santakumari, M.; Rama Das, V.S.

    1980-01-01

    The effect of diuron or atrazine on the rate of photosynthetic 14 CO 2 uptake of two each crop (Pisum Sativum and Pennisetum typhoides) and weed species (Amaranthus viridis and Cyperus rotundus) was studied. The results indicated a marked inhibition of 14 CO 2 fixation of leaves within two hours after diuron or atrazine treatment. However the resistant plants were able to exhibit a recovery of the net photosynthetic rate subsequently while the susceptible plants failed to recover. The results suggested that even with fully open stomata and available NADPH, the normal CO 2 fixation was not restored by herbicide treated leaves. (author)

  3. Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2.

    Science.gov (United States)

    Zhu, Xiancan; Song, Fengbin; Liu, Shengqun; Liu, Fulai

    2016-02-01

    Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM fungus were grown in two glasshouse cells with different CO2 concentrations (400 and 700 ppm) for 10 weeks. A (15)N isotope labeling technique was used to trace plant N uptake. Results showed that elevated CO2 increased AM fungal colonization. Under CO2 elevation, AM plants had higher C concentration and higher plant biomass than the non-AM plants. CO2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, (15)N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants than in non-AM controls under CO2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO2.

  4. Elevated CO2 plus chronic warming reduce nitrogen uptake and levels or activities of nitrogen-uptake and -assimilatory proteins in tomato roots.

    Science.gov (United States)

    Jayawardena, Dileepa M; Heckathorn, Scott A; Bista, Deepesh R; Mishra, Sasmita; Boldt, Jennifer K; Krause, Charles R

    2017-03-01

    Atmospheric CO 2 enrichment is expected to often benefit plant growth, despite causing global warming and nitrogen (N) dilution in plants. Most plants primarily procure N as inorganic nitrate (NO 3 - ) or ammonium (NH 4 + ), using membrane-localized transport proteins in roots, which are key targets for improving N use. Although interactive effects of elevated CO 2 , chronic warming and N form on N relations are expected, these have not been studied. In this study, tomato (Solanum lycopersicum) plants were grown at two levels of CO 2 (400 or 700 ppm) and two temperature regimes (30 or 37°C), with NO 3 - or NH 4 + as the N source. Elevated CO 2 plus chronic warming severely inhibited plant growth, regardless of N form, while individually they had smaller effects on growth. Although %N in roots was similar among all treatments, elevated CO 2 plus warming decreased (1) N-uptake rate by roots, (2) total protein concentration in roots, indicating an inhibition of N assimilation and (3) shoot %N, indicating a potential inhibition of N translocation from roots to shoots. Under elevated CO 2 plus warming, reduced NO 3 - -uptake rate per g root was correlated with a decrease in the concentration of NO 3 - -uptake proteins per g root, reduced NH 4 + uptake was correlated with decreased activity of NH 4 + -uptake proteins and reduced N assimilation was correlated with decreased concentration of N-assimilatory proteins. These results indicate that elevated CO 2 and chronic warming can act synergistically to decrease plant N uptake and assimilation; hence, future global warming may decrease both plant growth and food quality (%N). © 2016 Scandinavian Plant Physiology Society.

  5. In Vitro Comparison of the Effects of Diode Laser and CO2 Laser on Topical Fluoride Uptake in Primary Teeth.

    Science.gov (United States)

    Bahrololoomi, Zahra; Fotuhi Ardakani, Faezeh; Sorouri, Milad

    2015-08-01

    Fluoride therapy is important for control and prevention of dental caries. Laser irradiation can increase fluoride uptake especially when combined with topical fluoride application. The objective of this study was to compare the effects of CO2 and diode lasers on enamel fluoride uptake in primary teeth. Forty human primary molars were randomly assigned to four groups (n=10). The roots were removed and the crowns were sectioned mesiodistally into buccal and lingual halves as the experimental and control groups. All samples were treated with 5% sodium fluoride (NaF) varnish. The experimental samples in the four groups were irradiated with 5 or 7W diode or 1 or 2W CO2 laser for 15 seconds and were compared with the controls in terms of fluoride uptake, which was determined using an ion selective electrode after acid dissolution of the specimens. Data were analyzed by SPSS version 16 using ANOVA treating the control measurements as covariates. The estimated amount of fluoride uptake was 59.5± 16.31 ppm, 66.5± 14.9 ppm, 78.6± 12.43 ppm and 90.4± 11.51 ppm for 5W and 7 W diode and 1W and 2 W CO2 lasers, respectively, which were significantly greater than the values in the conventional topical fluoridation group (Pdiode laser and 1W CO2 laser, 5W and 7W diode laser, or 1W and 2W CO2 laser in this regard. The results showed that enamel surface irradiation by CO2 and diode lasers increases the fluoride uptake.

  6. Patterns and possible mechanisms of soil CO2 uptake in sandy soil.

    Science.gov (United States)

    Fa, Ke-Yu; Zhang, Yu-Qing; Wu, Bin; Qin, Shu-Gao; Liu, Zhen; She, Wei-Wei

    2016-02-15

    It has been reported that soils in drylands can absorb CO2, although the patterns and mechanisms of such a process remain under debate. To address this, we investigated the relationships between soil CO2 flux and meteorological factors and soil properties in Northwest China to reveal the reasons for "anomalous" soil CO2 flux in a desert ecosystem. Soil CO2 flux increased significantly and exponentially with surficial turbulence at the diel scale under dry conditions (Psoil CO2 flux demonstrated remarkable negative correlation with soil air pressure (Psoil water content was insufficient to dissolve the absorbed CO2 in dry conditions, but was sufficient in wet conditions. The concentration of soil HCO3(-) in the morning was higher than in the evening in dry conditions, but this pattern was reversed in wet conditions. These results imply that CO2 outgassing induced by turbulence, expansion of soil air, CO2 effusion from soil water, and carbonate precipitation during daytime can explain the abiotic diurnal CO2 release. Moreover, CO2 pumping from the atmosphere into the soil, caused mainly by carbonate dissolution, can account for nocturnal CO2 absorption in dry conditions. The abiotic soil CO2 flux pattern (CO2 absorption throughout the diel cycle) in wet conditions can be attributed to downward mass flow of soil CO2 and intensified soil air shrinkage, CO2 dissolving in soil water, and carbonate dissolution. These results provide a basis for determining the location of abiotic fixed carbon within soils in desert ecosystems. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2

    DEFF Research Database (Denmark)

    Zhu, Xiancan; Song, Fengbin; Liu, Shengqun

    2016-01-01

    Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM...... and higher plant biomass than the non-AM plants. CO2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, (15)N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants...... than in non-AM controls under CO2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO2....

  8. CO2 emissions due to energy combustion in the World in 2008

    International Nuclear Information System (INIS)

    2010-12-01

    This brief document presents and comments tables and figures of statistics about CO 2 emissions due to energy combustion in the World, as these emissions represent more than 95% of the whole CO 2 emissions. Data and statistics are given for different countries, notably the main Western and Asian countries. These emissions are considered globally, but they are also related to the GDP or to the population. If a slight increase (1,5%) of the global emissions has been noticed in 2008, they have decreased when they are related to the GDP (-2%). When emissions are related to the number of inhabitants, it appears that an African emits 20 times less than an inhabitant of the United States of America

  9. CO2 emissions due to energy combustion in the world in 2012

    International Nuclear Information System (INIS)

    Wong, Florine

    2015-01-01

    Illustrated by tables and graphs of data, this publication addresses and discusses the evolution of greenhouse gas emissions due to fossil energy combustion and consumption in the world (in the different continents, and in the main regions and countries). It outlines that these CO 2 emissions have increase of 1.2 per cent in 2012 (data are compared on the 1970-2012 period). The evolution of CO 2 emission intensity with respect to GDP is also presented and commented: a 2.1 per cent decrease has been noticed for 2012. The comparison between main geographic and economic areas indicates a 1 to 20 ratio between Africa and the USA for the emission level per capita

  10. Effects of elevated ozone on CO2 uptake and leaf structure in sugar maple under two light environments

    International Nuclear Information System (INIS)

    Bäck, J.; Vanderklein, D.W.; Topa, M.A.

    1999-01-01

    The interactive effects of ozone and light on leaf structure, carbon dioxide uptake and short-term carbon allocation of sugar maple (Acer saccharum Marsh.) seedlings were examined using gas exchange measurements and 14 C-macroautoradiographic techniques. Two-year-old sugar maple seedlings were fumigated from budbreak for 5 months with ambient or 3 × ambient ozone in open-top chambers, receiving either 35% (high light) or 15% (low light) of full sunlight. Ozone accelerated leaf senescence, and reduced net photosynthesis, 14 CO 2 uptake and stomatal conductance, with the effects being most pronounced under low light. The proportion of intercellular space increased in leaves of seedlings grown under elevated ozone and low light, possibly enhancing the susceptibility of mesophyll cells to ozone by increasing the cumulative dose per mesophyll cell. Indeed, damage to spongy mesophyll cells in the elevated ozone × low light treatment was especially frequent. 14 C macroautoradioraphy revealed heterogeneous uptake of 14 CO 2 in well defined areole regions, suggesting patchy stomatal behaviour in all treatments. However, in seedlings grown under elevated ozone and low light, the highest 14 CO 2 uptake occurred along larger veins, while interveinal regions exhibited little or no uptake. Although visible symptoms of ozone injury were not apparent in these seedlings, the cellular damage, reduced photosynthetic rates and reduced whole-leaf chlorophyll levels corroborate the visual scaling of whole-plant senescence, suggesting that the ozone × low light treatment accelerated senescence or senescence-like injury in sugar maple. (author)

  11. Uncertainty in the global oceanic CO2 uptake induced by wind forcing: quantification and spatial analysis

    Directory of Open Access Journals (Sweden)

    A. Roobaert

    2018-03-01

    Full Text Available The calculation of the air–water CO2 exchange (FCO2 in the ocean not only depends on the gradient in CO2 partial pressure at the air–water interface but also on the parameterization of the gas exchange transfer velocity (k and the choice of wind product. Here, we present regional and global-scale quantifications of the uncertainty in FCO2 induced by several widely used k formulations and four wind speed data products (CCMP, ERA, NCEP1 and NCEP2. The analysis is performed at a 1°  ×  1° resolution using the sea surface pCO2 climatology generated by Landschützer et al. (2015a for the 1991–2011 period, while the regional assessment relies on the segmentation proposed by the Regional Carbon Cycle Assessment and Processes (RECCAP project. First, we use k formulations derived from the global 14C inventory relying on a quadratic relationship between k and wind speed (k = c ⋅ U102; Sweeney et al., 2007; Takahashi et al., 2009; Wanninkhof, 2014, where c is a calibration coefficient and U10 is the wind speed measured 10 m above the surface. Our results show that the range of global FCO2, calculated with these k relationships, diverge by 12 % when using CCMP, ERA or NCEP1. Due to differences in the regional wind patterns, regional discrepancies in FCO2 are more pronounced than global. These global and regional differences significantly increase when using NCEP2 or other k formulations which include earlier relationships (i.e., Wanninkhof, 1992; Wanninkhof et al., 2009 as well as numerous local and regional parameterizations derived experimentally. To minimize uncertainties associated with the choice of wind product, it is possible to recalculate the coefficient c globally (hereafter called c∗ for a given wind product and its spatio-temporal resolution, in order to match the last evaluation of the global k value. We thus performed these recalculations for each wind product at the resolution and time period of our study

  12. Uncertainty in the global oceanic CO2 uptake induced by wind forcing: quantification and spatial analysis

    Science.gov (United States)

    Roobaert, Alizée; Laruelle, Goulven G.; Landschützer, Peter; Regnier, Pierre

    2018-03-01

    The calculation of the air-water CO2 exchange (FCO2) in the ocean not only depends on the gradient in CO2 partial pressure at the air-water interface but also on the parameterization of the gas exchange transfer velocity (k) and the choice of wind product. Here, we present regional and global-scale quantifications of the uncertainty in FCO2 induced by several widely used k formulations and four wind speed data products (CCMP, ERA, NCEP1 and NCEP2). The analysis is performed at a 1° × 1° resolution using the sea surface pCO2 climatology generated by Landschützer et al. (2015a) for the 1991-2011 period, while the regional assessment relies on the segmentation proposed by the Regional Carbon Cycle Assessment and Processes (RECCAP) project. First, we use k formulations derived from the global 14C inventory relying on a quadratic relationship between k and wind speed (k = c ṡ U102; Sweeney et al., 2007; Takahashi et al., 2009; Wanninkhof, 2014), where c is a calibration coefficient and U10 is the wind speed measured 10 m above the surface. Our results show that the range of global FCO2, calculated with these k relationships, diverge by 12 % when using CCMP, ERA or NCEP1. Due to differences in the regional wind patterns, regional discrepancies in FCO2 are more pronounced than global. These global and regional differences significantly increase when using NCEP2 or other k formulations which include earlier relationships (i.e., Wanninkhof, 1992; Wanninkhof et al., 2009) as well as numerous local and regional parameterizations derived experimentally. To minimize uncertainties associated with the choice of wind product, it is possible to recalculate the coefficient c globally (hereafter called c∗) for a given wind product and its spatio-temporal resolution, in order to match the last evaluation of the global k value. We thus performed these recalculations for each wind product at the resolution and time period of our study but the resulting global FCO2 estimates

  13. Co-ordination of NDH and Cup proteins in CO2 uptake in cyanobacterium Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Han, Xunling; Sun, Nan; Xu, Min; Mi, Hualing

    2017-06-01

    High and low affinity CO2-uptake systems containing CupA (NDH-1MS) and CupB (NDH-1MS'), respectively, have been identified in Synechocystis sp. PCC 6803, but it is yet unknown how the complexes function in CO2 uptake. In this work, we found that deletion of cupB significantly lowered the growth of cells, and deletion of both cupA and cupB seriously suppressed the growth below pH 7.0 even under 3% CO2. The rate of photosynthetic oxygen evolution was decreased slightly by deletion of cupA but significantly by deletion of cupB and more severely by deletion of both cupA and cupB, especially in response to changed pH conditions under 3% CO2. Furthermore, we found that assembly of CupB into NDH-1MS' was dependent on NdhD4 and NdhF4. NDH-1MS' was not affected in the NDH-1MS-degradation mutant and NDH-1MS was not affected in the NDH-1MS'-degradation mutants, indicating the existence of independent CO2-uptake systems under high CO2 conditions. The light-induced proton gradient across thylakoid membranes was significantly inhibited in ndhD-deletion mutants, suggesting that NdhDs functions in proton pumping. The carbonic anhydrase activity was suppressed partly in the cupA- or cupB-deletion mutant but severely in the mutant with both cupA and cupB deletion, indicating that CupA and CupB function in conversion of CO2 to HCO3-. In turn, deletion of cup genes lowered the transthylakoid membrane proton gradient and deletion of ndhDs decreased the CO2 hydration. Our results suggest that NDH-1M provides an alkaline region to activate Cup proteins involved in CO2 uptake. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  14. Assessment of brine migration risks along vertical pathways due to CO2 injection

    Science.gov (United States)

    Kissinger, Alexander; Class, Holger

    2015-04-01

    displaced brine due to CO2 injection and compare it to the natural fluid exchange between shallow and deep aquifers in order to asses possible damage.

  15. Why Southern Ocean uptake of anthropogenic CO2 may be decreasing

    CSIR Research Space (South Africa)

    Mongwe, P

    2012-10-01

    Full Text Available to the warm surface water and its influence on CO2 solubility (Figures 2 and 3). The decline is DIC with depth correlates with the decrease in temperature (Figures 2 and 3), as colder water holds more CO2. The Southern Ocean has particularly high DIC... southwards, upwelling is also expected move more southwards, which may result in more intense CO2 outgassing. The emitted CO2 contributes to green house gases, which alter the heat balance and result in increased average temperatures. REFERENCES Le...

  16. The effects of elevated environmental CO2 on nitrite uptake in the air-breathing clown knifefish, Chitala ornata

    DEFF Research Database (Denmark)

    Le Thi Hong Gam; Jensen, Frank Bo; Do Thi Thanh Huong

    2018-01-01

    hypercapnia) and nitrite for 96 h. Blood was sampled to measure acid-base status, haemoglobin derivatives and plasma ions. Plasma nitrite increased for 48 h, but levels stayed below the exposure concentration, and subsequently decreased as a result of nitrite detoxification to nitrate. The total uptake......Nitrite and carbon dioxide are common environmental contaminants in the intensive aquaculture ponds used to farm clown knifefish (Chitala ornata) in the Mekong delta, Vietnam. Here we tested the hypothesis that hypercapnia reduces nitrite uptake across the gills, because pH regulation will reduce...... chloride uptake and hence nitrite uptake as the two ions compete for the same transport route via the branchial HCO3-/Cl- exchanger. Fish fitted with arterial catheters were exposed to normocapnic/normoxic water (control), nitrite (1 mM), hypercapnia (21 mmHg CO2), or combined hypercapnia (acclimated...

  17. Regional impacts of climate change and atmospheric CO2 on future ocean carbon uptake: A multi-model linear feedback analysis

    OpenAIRE

    Roy Tilla; Bopp Laurent; Gehlen Marion; Schneider Birgitt; Cadule Patricia; Frölicher Thomas; Segschneider Jochen; Tijputra Jerry; Heinze Christoph; Joos Fortunat

    2011-01-01

    The increase in atmospheric CO2 over this century depends on the evolution of the oceanic air–sea CO2 uptake which will be driven by the combined response to rising atmospheric CO2 itself and climate change. Here the future oceanic CO2 uptake is simulated using an ensemble of coupled climate–carbon cycle models. The models are driven by CO2 emissions from historical data and the Special Report on Emissions Scenarios (SRES) A2 high emission scenario. A linear feedback analysis successfully sep...

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

    Science.gov (United States)

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

    2017-05-23

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

  19. Climate forcing due to optimization of maximal leaf conductance in subtropical vegetation under rising CO2

    NARCIS (Netherlands)

    Boer, H.J. de; Lammertsma, E.I.; Wagner-Cremer, F.; Dilcher, D.L.; Wassen, M.J.; Dekker, S.C.

    2011-01-01

    Plant physiological adaptation to the global rise in atmospheric CO 2 concentration (CO2) is identified as a crucial climatic forcing. To optimize functioning under rising CO2, plants reduce the diffusive stomatal conductance of their leaves (gs) dynamically by closing stomata and structurally by

  20. Validity of reciprocity rule on mouse skin thermal damage due to CO2 laser irradiation

    Science.gov (United States)

    Parvin, P.; Dehghanpour, H. R.; Moghadam, M. S.; Daneshafrooz, V.

    2013-07-01

    CO2 laser (10.6 μm) is a well-known infrared coherent light source as a tool in surgery. At this wavelength there is a high absorbance coefficient (860 cm-1), because of vibration mode resonance of H2O molecules. Therefore, the majority of the irradiation energy is absorbed in the tissue and the temperature of the tissue rises as a function of power density and laser exposure duration. In this work, the tissue damage caused by CO2 laser (1-10 W, ˜40-400 W cm-2, 0.1-6 s) was measured using 30 mouse skin samples. Skin damage assessment was based on measurements of the depth of cut, mean diameter of the crater and the carbonized layer. The results show that tissue damage as assessed above parameters increased with laser fluence and saturated at 1000 J cm-2. Moreover, the damage effect due to high power density at short duration was not equivalent to that with low power density at longer irradiation time even though the energy delivered was identical. These results indicate the lack of validity of reciprocity (Bunsen-Roscoe) rule for the thermal damage.

  1. The effect of elevated CO2 and temperature on nutrient uptake by plants grown in basaltic soil

    Science.gov (United States)

    Villasenor Iribe, E.; Dontsova, K.; Juarez, S.; Le Galliard, J. F.; Chollet, S.; Llavata, M.; Massol, F.; Barré, P.; Gelabert, A.; Daval, D.; Troch, P.; Barron-Gafford, G.; Van Haren, J. L. M.; Ferrière, R.

    2017-12-01

    Mineral weathering is an important process in soil formation. The interactions between the hydrologic, geologic and atmospheric cycles often determine the rate at which weathering occurs. Elements and nutrients weathered from the soil by water can be removed from soils in the runoff and seepage, but they can also remain in situ as newly precipitated secondary minerals or in biomass as a result of plant uptake. Here we present data from an experiment that was conducted at the controlled environment facility, Ecotron Ile-de-France (Saint-Pierre-les-Nemours, France) that studied mineral weathering and plant growth in granular basaltic material with high glass content that is being used to simulate soil in large scale Biosphere 2 Landscape Evolution Observatory (LEO) project. The experiment used 3 plant types: velvet mesquite (Prosopis velutina), green spangletop (Leptochloa dubia), and alfalfa (Medicago sativa), which were grown under varying temperature and CO2 conditions. We hypothesized that plants grown under warmer, higher CO2 conditions would have larger nutrient concentrations as more mineral weathering would occur. Results of plant digestions and analysis showed that plant concentrations of lithogenic elements were significantly influenced by the plant type and were different between above- and below-ground parts of the plant. Temperature and CO2 treatment effects were less pronounced, but we observed significant temperature effect on plant uptake. A number of major and trace elements showed increase in concentration with increase in temperature at elevated atmospheric CO2. Effect was observed both in the shoots and in the roots, but more significant differences were observed in the shoots. Results presented here indicate that climate change would have strong effect on plant uptake and mobility of weathered elements during soil formation and give further evidence of interactions between abiotic and biological processes in terrestrial ecosystems.

  2. Elevated CO2 increases Cs uptake and alters microbial communities and biomass in the rhizosphere of Phytolacca americana Linn (pokeweed) and Amaranthus cruentus L. (purple amaranth) grown on soils spiked with various levels of Cs

    International Nuclear Information System (INIS)

    Song, Ningning; Zhang, Ximei; Wang, Fangli; Zhang, Changbo; Tang, Shirong

    2012-01-01

    General concern about increasing global atmospheric CO 2 levels owing to the ongoing fossil fuel combustion and elevated levels of radionuclides in the environment, has led to growing interest in the responses of plants to interactive effects of elevated CO 2 and radionuclides in terms of phytoremediation and food safety. To assess the combined effects of elevated CO 2 and cesium contamination on plant biomass, microbial activities in the rhizosphere soil and Cs uptake, Phytolacca americana Linn (pokeweed, C3 specie) and Amaranthus cruentus L. (purple amaranth, C4 specie) were grown in pots of soils containing five levels of cesium (0, 100, 300, 500 and 1000 mg Cs kg −1 ) under two levels of CO 2 (360 and 860 μL L −1 , respectively). Shoot and root biomass of P. americana and Amaranthus crentus was generally higher under elevated CO 2 than under ambient CO 2 for all treatments. Both plant species exhibited higher Cs concentration in the shoots and roots under elevated CO 2 than ambient CO 2 . For P. americana grown at 0, 100, 300, 500 and 1000 mg Cs kg −1 , the increase magnitude of Cs concentration due to elevated CO 2 was 140, 18, 11, 34 and 15% in the shoots, and 150, 20, 14, 15 and 19% in the roots, respectively. For A. cruentus, the corresponding value was 118, 28, 21, 14 and 17% in the shoots, and 126, 6, 11, 17 and 22% in the roots, respectively. Higher bioaccumulation factors were noted for both species grown under elevated CO 2 than ambient CO 2 . The populations of bacteria, actinomycetes and fungi, and the microbial C and N in the rhizosphere soils of both species were higher at elevated CO 2 than at ambient CO 2 with the same concentration of Cs. The results suggested that elevated CO 2 significantly affected plant biomass, Cs uptake, soil C and N concentrations, and community composition of soil microbes associated with P. americana and A. cruentus roots. The knowledge gained from this investigation constitutes an important advancement in

  3. Effects of elevated CO2, warming and drought episodes on plant carbon uptake in a temperate heath ecosystem are controlled by soil water status

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard

    2011-01-01

    The impact of elevated CO2, periodic drought and warming on photosynthesis and leaf characteristics of the evergreen dwarf shrub Calluna vulgaris in a temperate heath ecosystem was investigated. Photosynthesis was reduced by drought in midsummer and increased by elevated CO2 throughout the growing...... season, whereas warming only stimulated photosynthesis early in the year. At the beginning and end of the growing season, a T × CO2 interaction synergistically stimulated plant carbon uptake in the combination of warming and elevated CO2. At peak drought, the D × CO2 interaction antagonistically down......-regulated photosynthesis, suggesting a limited ability of elevated CO2 to counteract the negative effect of drought. The response of photosynthesis in the full factorial combination (TDCO2) could be explained by the main effect of experimental treatments (T, D, CO2) and the two-factor interactions (D × CO2, T × CO2...

  4. One strategy for estimating the potential soil carbon storage due to CO2 fertilization

    International Nuclear Information System (INIS)

    Harrison, K.G.; Bonani, G.

    1994-01-01

    Soil radiocarbon measurements can be used to estimate soil carbon turnover rates and inventories. A labile component of soil carbon has the potential to respond to perturbations such as CO 2 fertilization, changing climate, and changing land use. Soil carbon has influenced past and present atmospheric CO 2 levels and will influence future levels. A model is used to calculate the amount of additional carbon stored in soil because of CO 2 fertilization

  5. Increasing net CO2 uptake by a Danish beech forest during the period from 1996 to 2009

    DEFF Research Database (Denmark)

    Pilegaard, Kim; Ibrom, Andreas; Courtney, Michael

    2011-01-01

    and atmospheric CO2 concentration. The net CO2 exchange (NEE) was measured by the eddy covariance method. Ecosystem respiration (RE) was estimated from nighttime values and gross ecosystem exchange (GEE) was calculated as the sum of RE and NEE. Over the years the beech forest acted as a sink of on average of 157...... g C m−2 yr−1. In one of the years only, the forest acted as a small source. During 1996–2009 a significant increase in annual NEE was observed. A significant increase in GEE and a smaller and not significant increase in RE was also found. Thus the increased NEE was mainly attributed to an increase...... in GEE. The overall trend in NEE was significant with an average increase in uptake of 23 g C m−2 yr−2. The carbon uptake period (i.e. the period with daily net CO2 gain) increased by 1.9 days per year, whereas there was a non significant tendency of increase of the leafed period. This means...

  6. Ultrasonic Monitoring of CO2 Uptake and Release from Sand Packs*

    Science.gov (United States)

    Toffelmier, D. A.; Dufrane, W. L.; Bonner, B. P.; Viani, B. E.; Berge, P. A.

    2002-12-01

    Sequestration of atmospheric CO2 occurs naturally during the formation of calcite cement in sedimentary rock. Acceleration of this process has been proposed as a means of reducing the atmospheric concentration of CO2, which is a major cause of global warming. Calcite may also be precipitated when highly alkaline waste fluid is introduced into the vadose zone from leaking storage tanks. Seismic methods have potential for monitoring these processes. We devised an experiment, guided by geochemical modeling, to determine how the formation of calcite cement in unsaturated sand affects wave propagation. We used the ultrasonic pulse transmission method to measure compressional (P) and shear (S) wave velocities at ultrasonic frequencies (100-500 kHz) through packs of Ottawa sand containing chemically active pore fluids. The samples were saturated with water containing 0.1mol/L of Ca(OH)2 and 0.1mol/L of NaCl and then drained by flowing water saturated, CO2 free N2 gas, to a residual saturation of ~5%, so that the remaining pore fluid resides mainly in pendular spaces between the sand grains. Ambient air saturated with water and containing atmospheric concentration of CO2 was then passed through the sample to effect the precipitation of calcite. Finally, pure water saturated CO2, was flushed through the sample to dissolve most of the precipitated calcite. Over a three day period, measurable changes in Vp and Vs were observed following water saturation, desaturation, calcite precipitation, and calcite dissolution treatments. Changes in the contents of the pore space require waveforms to be recorded before and after each stage of the experiment so both the short and long range effects can be seen. Wave velocities were slow, as is typical for unconsolidated materials, for the dry sand, with values of 365m/s for Vp and 163m/s for Vs. Compressional velocities increased upon desaturation (443m/s), and again following calcite precipitation (460m/s). The compressional velocity

  7. High air-sea CO 2 uptake rates in nearshore and shelf areas of Southern Greenland: Temporal and spatial variability

    DEFF Research Database (Denmark)

    Rysgaard, Søren; Mortensen, J.; Juul-Pedersen, T.

    2012-01-01

    significant correlation between average annual gross primary production and annual air-sea flux during 2005-2010, which suggests that regulation of pCO 2 in the fjord is more complex. Despite three confined periods with supersaturated pCO 2 conditions in surface waters during 2005-2010, Godthåbsfjord can......The present study is based on hourly samplings of wind speed, monthly sampling sessions of temperature, salinity, dissolved inorganic carbon, alkalinity, nutrients, primary productivity and vertical export in the outer sill region (station GF3) of a sub-arctic SW Greenland fjord (Godthåbsfjord......) through 2005-2010. Air-sea CO 2 fluxes varied at GF3 from c. -20gCm -2month -1 (uptake from the atmosphere) to 25gCm -2month -1 (release to the atmosphere) during 2005-10. The average annual air-sea CO 2 flux of -83 to -108gCm -2yr -1 was within the range of the local gross annual primary productivity...

  8. Consequences of thermal fracture developments due to injection cold CO2 into depleted gas fields

    NARCIS (Netherlands)

    Peters, E.; Pizzocolo, F.; Loeve, D.; Fokker, P.A.; Hofstee, C.; Orlic, B.; Maas, J.G.

    2013-01-01

    CO2 storage is planned in a depleted gas field called P18, which is located offshore in the vicinity of the Dutch coast. This project is also known as the ROAD project, which is the Rotterdam capture and storage demonstration project. In the P18-4 compartment, cold CO2 will be injected into a

  9. 2007 CO2 emissions due to energy combustion in the world

    International Nuclear Information System (INIS)

    2010-01-01

    Worldwide energy combustion contributes to more than 95% of the global CO 2 emissions. According to the last International Energy Agency (IEA) results, these emissions have raised by 3.3% with respect to 2006 and by 38% with respect to 1990 with a total of about 29 Gt of CO 2 . After a new 8% boom in 2007, China's emissions have tripled since 1990 with a total exceeding 6 Gt of CO 2 . China has become the first CO 2 emitter in front of the USA. When compared to the number of inhabitants, China's emissions are comparable to the world average (4.4 t CO 2 /hab) but remain four times lower than the ones of the USA. (J.S.)

  10. Using stable isotopes in tree rings to evaluate the impact of urban pollution on CO2 uptake by forests

    International Nuclear Information System (INIS)

    Savard, M.M.; Begin, Ch.; Marion, J.

    2004-01-01

    Contributions addressing the impact of industrial activities on tree growth are scarce; likewise, only a few studies document δ 13 C values in growth rings of natural specimens subjected to potentially toxic industrial emissions. These last studies suggest that the SO 2 emissions affect the physiology of trees and induce changes in their carbon isotope ratios. It has been reported that copper-smelter emissions reduce the C uptake of exposed trees by 35 % to 6 % relatively to unexposed trees, in growth stands located between 9 and 120 km from the smelter. In the context of the globally increasing concentrations of CO 2 in the atmosphere, what is the net impact of the large-scale annual reduction of CO 2 uptake induced by phyto-toxic pollutants? What should we expect for trees growing in regions submitted to urban diffuse pollution? It has been recently suggested on the basis of plant biomass measurements in the New York region that urban pollution can relatively reduce plant growth, but the effect is apparently greater in distant rural sites than in peri-urban and urban ones. Is this representative of numerous urban settings? If the answer to this question is yes, the pollution-effect parameter should be considered in the global annual forest C budget, particularly for the highly industrialized northern hemisphere. The specific objectives of this study are to: (1) measure the tissue increments of the stems and determine the C isotopic ratios in tree-ring cellulose of selected trees undergoing pollution stress in selected peri-urban stands; (2) present a secular time series of the CO 2 uptake by forests peripheral to a large urban region; and (3) evaluate stable isotope dendro-geochemistry as a proxy for past changes of air quality in urban and peri-urban settings. (authors)

  11. Enhanced uptake and photoactivation of topical methyl aminolevulinate after fractional CO2 laser pretreatment

    DEFF Research Database (Denmark)

    Haedersdal, M; Katsnelson, J; Sakamoto, F H

    2011-01-01

    Photodynamic therapy (PDT) of thick skin lesions is limited by topical drug uptake. Ablative fractional resurfacing (AFR) creates vertical channels that may facilitate topical PDT drug penetration and improve PDT-response in deep skin layers. The purpose of this study was to evaluate whether pre-...

  12. Enhanced uptake and photoactivation of topical methyl aminolevulinate after fractional CO2 laser pretreatment

    DEFF Research Database (Denmark)

    Haedersdal, M; Katsnelson, J; Sakamoto, F H

    2011-01-01

    Photodynamic therapy (PDT) of thick skin lesions is limited by topical drug uptake. Ablative fractional resurfacing (AFR) creates vertical channels that may facilitate topical PDT drug penetration and improve PDT-response in deep skin layers. The purpose of this study was to evaluate whether pre......-treating the skin with AFR before topically applied methyl aminolevulinate (MAL) could enable a deep PDT-response....

  13. A biophysical approach using water deficit factor for daily estimations of evapotranspiration and CO2 uptake in Mediterranean environments

    Science.gov (United States)

    Helman, David; Lensky, Itamar M.; Osem, Yagil; Rohatyn, Shani; Rotenberg, Eyal; Yakir, Dan

    2017-09-01

    Estimations of ecosystem-level evapotranspiration (ET) and CO2 uptake in water-limited environments are scarce and scaling up ground-level measurements is not straightforward. A biophysical approach using remote sensing (RS) and meteorological data (RS-Met) is adjusted to extreme high-energy water-limited Mediterranean ecosystems that suffer from continuous stress conditions to provide daily estimations of ET and CO2 uptake (measured as gross primary production, GPP) at a spatial resolution of 250 m. The RS-Met was adjusted using a seasonal water deficit factor (fWD) based on daily rainfall, temperature and radiation data. We validated our adjusted RS-Met with eddy covariance flux measurements using a newly developed mobile lab system and the single active FLUXNET station operating in this region (Yatir pine forest station) at a total of seven forest and non-forest sites across a climatic transect in Israel (280-770 mm yr-1). RS-Met was also compared to the satellite-borne MODIS-based ET and GPP products (MOD16 and MOD17, respectively) at these sites.Results show that the inclusion of the fWD significantly improved the model, with R = 0.64-0.91 for the ET-adjusted model (compared to 0.05-0.80 for the unadjusted model) and R = 0.72-0.92 for the adjusted GPP model (compared to R = 0.56-0.90 of the non-adjusted model). The RS-Met (with the fWD) successfully tracked observed changes in ET and GPP between dry and wet seasons across the sites. ET and GPP estimates from the adjusted RS-Met also agreed well with eddy covariance estimates on an annual timescale at the FLUXNET station of Yatir (266 ± 61 vs. 257 ± 58 mm yr-1 and 765 ± 112 vs. 748 ± 124 gC m-2 yr-1 for ET and GPP, respectively). Comparison with MODIS products showed consistently lower estimates from the MODIS-based models, particularly at the forest sites. Using the adjusted RS-Met, we show that afforestation significantly increased the water use efficiency (the ratio of carbon uptake to ET) in this region

  14. Diffraction efficiency enhancement of femtosecond laser-engraved diffraction gratings due to CO2 laser polishing

    International Nuclear Information System (INIS)

    Choi, Hun-Kook; Jung, Deok; Sohn, Ik-Bu; Noh, Young-Chul; Lee, Yong-Tak; Kim, Jin-Tae; Ahsan, Shamim

    2014-01-01

    This research demonstrates laser-assisted fabrication of high-efficiency diffraction gratings in fused-silica glass samples. Initially, femtosecond laser pulses are used to engrave diffraction gratings on the glass surfaces. Then, these micro-patterned glass samples undergo CO 2 laser polishing process. unpolished diffraction gratings encoded in the glass samples show an overall diffraction efficiency of 18.1%. diffraction gratings imprinted on the glass samples and then polished four times by using a CO 2 laser beam attain a diffraction efficiency of 32.7%. We also investigate the diffraction patterns of the diffraction gratings encoded on fused-silica glass surfaces. The proposed CO 2 laser polishing technique shows great potential in patterning high-efficiency diffraction gratings on the surfaces of various transparent materials.

  15. The Characteristics of Peats and Co2 Emission Due to Fire in Industrial Plant Forests

    Science.gov (United States)

    Ratnaningsih, Ambar Tri; Rayahu Prasytaningsih, Sri

    2017-12-01

    Riau Province has a high threat to forest fire in peat soils, especially in industrial forest areas. The impact of fires will produce carbon (CO2) emissions in the atmosphere. The magnitude of carbon losses from the burning of peatlands can be estimated by knowing the characteristics of the fire peat and estimating CO2 emissions produced. The objectives of the study are to find out the characteristics of fire-burning peat, and to estimate carbon storage and CO2 emissions. The location of the research is in the area of industrial forest plantations located in Bengkalis Regency, Riau Province. The method used to measure peat carbon is the method of lost in ignation. The results showed that the research location has a peat depth of 600-800 cm which is considered very deep. The Peat fiber content ranges from 38 to 75, classified as hemic peat. The average bulk density was 0.253 gram cm-3 (0.087-0,896 gram cm-3). The soil ash content is 2.24% and the stored peat carbon stock with 8 meter peat thickness is 10723,69 ton ha-1. Forest fire was predicted to burn peat to a depth of 100 cm and produced CO2 emissions of 6,355,809 tons ha-1.

  16. Regional-scale brine migration along vertical pathways due to CO2 injection - Part 1: The participatory modeling approach

    Science.gov (United States)

    Scheer, Dirk; Konrad, Wilfried; Class, Holger; Kissinger, Alexander; Knopf, Stefan; Noack, Vera

    2017-06-01

    Saltwater intrusion into potential drinking water aquifers due to the injection of CO2 into deep saline aquifers is one of the potential hazards associated with the geological storage of CO2. Thus, in a site selection process, models for predicting the fate of the displaced brine are required, for example, for a risk assessment or the optimization of pressure management concepts. From the very beginning, this research on brine migration aimed at involving expert and stakeholder knowledge and assessment in simulating the impacts of injecting CO2 into deep saline aquifers by means of a participatory modeling process. The involvement exercise made use of two approaches. First, guideline-based interviews were carried out, aiming at eliciting expert and stakeholder knowledge and assessments of geological structures and mechanisms affecting CO2-induced brine migration. Second, a stakeholder workshop including the World Café format yielded evaluations and judgments of the numerical modeling approach, scenario selection, and preliminary simulation results. The participatory modeling approach gained several results covering brine migration in general, the geological model sketch, scenario development, and the review of the preliminary simulation results. These results were included in revised versions of both the geological model and the numerical model, helping to improve the analysis of regional-scale brine migration along vertical pathways due to CO2 injection.

  17. Detecting Patterns of Changing Carbon Uptake in Alaska Using Sustained In Situ and Remote Sensing CO2 Observations

    Science.gov (United States)

    Parazoo, N.; Miller, C. E.; Commane, R.; Wofsy, S. C.; Koven, C.; Lawrence, D. M.; Lindaas, J.; Chang, R. Y. W.; Sweeney, C.

    2015-12-01

    The future trajectory of Arctic ecosystems as a carbon sink or source is of global importance due to vast quantities of carbon in permafrost soils. Over the last few years, a sustained set of airborne (NOAA-PFA, NOAA-ACG, and CARVE) and satellite (OCO-2 and GOSAT) atmospheric CO2 mole fraction measurements have provided unprecedented space and time scale sampling density across Alaska, making it possible to study the Arctic carbon cycle in more detail than ever before. Here, we use a synthesis of airborne and satellite CO2 over the 2009-2013 period with simulated concentrations from CLM4.5 and GEOS-Chem to examine the extent to which regional-scale carbon cycle changes in Alaska can be distinguished from interannual variability and long-range transport. We show that observational strategies focused on sustained profile measurements spanning continental interiors provide key insights into magnitude, duration, and variability of Summer sink activity, but that cold season sources are currently poorly resolved due to lack of sustained spatial sampling. Consequently, although future CO2 budgets dominated by enhanced cold season emission sources under climate warming and permafrost thaw scenarios are likely to produce substantial changes to near-surface CO2 gradients and seasonal cycle amplitude, they are unlikely to be detected by current observational strategies. We conclude that airborne and ground-based networks that provide more spatial coverage in year round profiles will help compensate for systematic sampling gaps in NIR passive satellite systems and provide essential constraints for Arctic carbon cycle changes.

  18. Changes in carbon uptake and allocation patterns in Quercus robur seedlings in response to elevated CO2 and water stress: an evaluation with 13C labelling

    International Nuclear Information System (INIS)

    Vivin, P.; Guehl, J.M.

    1997-01-01

    A semi-closed (CO2)-C-13 labelling system (1.5% C-13) was used to assess both carbon uptake and allocation within pedunculate oak seedlings (Quercus robur L) grown under ambient (350 vpm) and elevated (700 vpm) atmospheric CO2 concentration ([CO2]) and in either well-watered or droughted conditions. Pulse-chase C-13 labelling data highlighted the direct positive effect of elevated CO2 on photosynthetic carbon acquisition. Consequently, in well-watered conditions, CO2-enriched plants produced 1.52 times more biomass (dry mass at harvest) and 1.33 times more dry root matter (coarse plus fine roots) over the 22-week growing period than plants grown under ambient [CO2]. The root/shoot biomass ratio was decreased both by drought and [CO2], despite lower N concentrations in CO2-enriched plants. However, both long-term and short-term C allocation to fine roots were not altered by CO2, and relative specific allocation (RSA), a parameter expressing sink strength, was hip her in all plant organs under 700 vpm compared to 350 vpm. Results showed that C availability for growth and metabolic processes was greater in fine roots of oaks grown under an elevated CO2 atmosphere irrespective of soil water availability [fr

  19. A biophysical approach using water deficit factor for daily estimations of evapotranspiration and CO2 uptake in Mediterranean environments

    Directory of Open Access Journals (Sweden)

    D. Helman

    2017-09-01

    Full Text Available Estimations of ecosystem-level evapotranspiration (ET and CO2 uptake in water-limited environments are scarce and scaling up ground-level measurements is not straightforward. A biophysical approach using remote sensing (RS and meteorological data (RS–Met is adjusted to extreme high-energy water-limited Mediterranean ecosystems that suffer from continuous stress conditions to provide daily estimations of ET and CO2 uptake (measured as gross primary production, GPP at a spatial resolution of 250 m. The RS–Met was adjusted using a seasonal water deficit factor (fWD based on daily rainfall, temperature and radiation data. We validated our adjusted RS–Met with eddy covariance flux measurements using a newly developed mobile lab system and the single active FLUXNET station operating in this region (Yatir pine forest station at a total of seven forest and non-forest sites across a climatic transect in Israel (280–770 mm yr−1. RS–Met was also compared to the satellite-borne MODIS-based ET and GPP products (MOD16 and MOD17, respectively at these sites.Results show that the inclusion of the fWD significantly improved the model, with R =  0.64–0.91 for the ET-adjusted model (compared to 0.05–0.80 for the unadjusted model and R =  0.72–0.92 for the adjusted GPP model (compared to R =  0.56–0.90 of the non-adjusted model. The RS–Met (with the fWD successfully tracked observed changes in ET and GPP between dry and wet seasons across the sites. ET and GPP estimates from the adjusted RS–Met also agreed well with eddy covariance estimates on an annual timescale at the FLUXNET station of Yatir (266 ± 61 vs. 257 ± 58 mm yr−1 and 765 ± 112 vs. 748 ± 124 gC m−2 yr−1 for ET and GPP, respectively. Comparison with MODIS products showed consistently lower estimates from the MODIS-based models, particularly at the forest sites. Using the adjusted RS–Met, we show that afforestation

  20. Effects of elevated CO2 on soil organic matter turnover and plant nitrogen uptake: First results from a dual labeling mesocosm experiment

    Science.gov (United States)

    Eder, Lucia Muriel; Weber, Enrico; Schrumpf, Marion; Zaehle, Sönke

    2017-04-01

    The response of plant growth to elevated concentrations of CO2 (eCO2) is often constrained by plant nitrogen (N) uptake. To overcome potential N limitation, plants may invest photosynthetically fixed carbon (C) into N acquiring strategies, including fine root biomass, root exudation, or C allocation to mycorrhizal fungi. In turn, these strategies may affect the decomposition of soil organic matter, leading to uncertainties in net effects of eCO2 on C storage. To gain more insight into these plant-soil C-N-interactions, we combined C and N stable isotope labeling in a mesocosm experiment. Saplings of Fagus sylvatica L. were exposed to a 13CO2 enriched atmosphere at near ambient (380 ppm) or elevated (550 ppm) CO2 concentrations for four months of the vegetation period in 2016. Aboveground and belowground net CO2 fluxes were measured separately and the 13C label enabled partitioning of total soil CO2 efflux into old, soil derived and new, plant-derived C. We used ingrowth cores to assess effects of eCO2on belowground C allocation and plant N uptake in more detail and in particular we evaluated the relative importance of ectomycorrhizal associations. In the soil of each sapling, ingrowth cores with different mesh sizes allowed fine roots or only mycorrhizal hyphae to penetrate. In one type of ingrowth core each, we incorporated fine root litter that was enriched in 15N. Additionally, total N uptake was estimated by using 15N enriched saplings and unlabeled control plants. We found that eCO2 increased aboveground net CO2 exchange rates by 19% and total soil respiration by 11%. The eCO2 effect for GPP and also for NPP was positive (+23% and +11%, respectively). By combining gaseous C fluxes with data on new and old C stocks in bulk soil and plants through destructive harvesting in late autumn 2016, we will be able to infer net effects of eCO2 on the fate of C in these mesocosms. Biomass allocation patterns can reveal physiological responses to high C availability under

  1. Dividing by four CO2 releases due to energy: the Negatep scenario

    International Nuclear Information System (INIS)

    Acket, C.; Bacher, P.

    2011-01-01

    The Negatep scenario aims at dividing CO 2 releases by 4, which means, more or less, dividing the consumption of fossil energies by the same factor, in order to comply with the French 2005 energy act. After a description of the situation in 2006, of trends, and a recall of the objectives defined by the 'Grenelle de l'Environnement' regarding energy savings and renewable energies, the authors show that reaching such a reduction requires to: decrease to nearly zero oil and gas in the residential and tertiary sectors, reduce significantly the use of oil in the transport sector, reduce significantly the use of fossil fuels in industry, increase massively the share of electricity in the energy mix, maintain the share of nuclear in the electricity generation and, as long as the storage of electricity is not developed, limit the share of intermittent energies to a level compatible with that of gas turbines. The study shows that the proposed measures can fulfill the objectives for 2020 proposed by the 'Grenelle de l'Environnement'

  2. Influence of exogenous urea on photosynthetic pigments, (14)CO 2 uptake, and urease activity in Elodea densa-environmental implications.

    Science.gov (United States)

    Maleva, Maria; Borisova, Galina; Chukina, Nadezda; Nekrasova, Galina; Prasad, M N V

    2013-09-01

    This paper analyzes the effect of exogenous urea in increased concentration gradient (0, 100, 500 and 1,000 mg L(-1)) on photosynthetic pigments (measured spectrophotometrically), uptake of (14)CO2 (using radioisotope), and urease activity (by measuring ammonia with Nessler's reagent) in leaves of Elodea densa Planch. We have observed that low concentration of urea (100 mg L(-1)) stimulates the accumulation of photosynthetic pigments and intensifies photosynthesis in E. densa, whereas high concentration (1,000 mg L(-1)) suppresses these processes. Urease activity increased by approximately 2.7 and 8 fold when exogenous urea concentrations were 100 and 500 mg L(-1), respectively. However, exogenous urea in high concentration (1,000 mg L(-1)) decreased urease activity by 1.5 fold compared to the control. The necessity of mitigating urea and other nitrogen-containing compounds (NH3 from urea) in water bodies has been discussed with emphasis on the potential for phytoremediation of urea using common water weed viz. E. densa.

  3. Characteristics of Atmosphere-Ocean CO2 Exchange due to Typhoon Activities over the East Asian Region

    Science.gov (United States)

    Lee, G.; Cho, C. H.; Lim, D. H.; Sun, M.; Lee, J.; Byun, Y. H.; Lee, J.

    2014-12-01

    Although the oceans are generally known as a net carbon sink in global sense, it is expected that CO₂release from oceans can occur locally depending on specific weather. This study addresses investigation of change in CO2 exchange between atmosphere and ocean due to typhoon activities, using "Carbon Tracker-Asia (CTA)". The CTA has constructed and managed at National Institute of Meteorological Research(NIMR) based on Carbon Tracker developed by NOAA. In order to examine effect of typhoon on change in air-sea CO2 exchange, we selected several cases which typhoon approached to Korean peninsula in the summertime and their tracks are similar to each other. Also, we analyzed difference between CO2 flux along typhoon tracks and other adjacent region not to be directly affected by typhoon in these cases. There is a difference in ocean fluxes around 15 gC/m²yr over strong typhoon areas compared to other areas. This difference varied with the wind speeds, the correlation coefficient between the ocean and the wind flux was found 0.7. Changes in carbon flux to affect the concentration of CO₂ in the atmosphere near surface instantly.

  4. Strong shift from HCO3 (-) to CO 2 uptake in Emiliania huxleyi with acidification: new approach unravels acclimation versus short-term pH effects.

    Science.gov (United States)

    Kottmeier, Dorothee M; Rokitta, Sebastian D; Tortell, Philippe D; Rost, Björn

    2014-09-01

    Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 μatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative contributions of CO2 and HCO3 (-) uptake depended strongly on the assay pH. At pH values ≤ 8.1, cells preferentially used CO2 (≥ 90 % CO2), whereas at pH values ≥ 8.3, cells progressively increased the fraction of HCO3 (-) uptake (~45 % CO2 at pH 8.7 in diploid cells; ~55 % CO2 at pH 8.5 in haploid cells). In contrast to the short-term effect of the assay pH, the pCO2 acclimation history had no significant effect on the carbon uptake behavior. A numerical sensitivity study confirmed that the pH-modification in the (14)C disequilibrium method yields reliable results, provided that model parameters (e.g., pH, temperature) are kept within typical measurement uncertainties. Our results demonstrate a high plasticity of E. huxleyi to rapidly adjust carbon acquisition to the external carbon supply and/or pH, and provide an explanation for the paradoxical observation of high CO2 sensitivity despite the apparently high HCO3 (-) usage seen in previous studies.

  5. 大气CO2浓度升高对绿豆生长及C、N吸收的影响%Effects of enriched atmospheric CO2 on the growth and uptake of N and C in mung bean

    Institute of Scientific and Technical Information of China (English)

    郝兴宇; 李萍; 杨宏斌; 韩雪; 林而达

    2011-01-01

    The inter-governmental panel on climate change projects that atmospheric [CO2] will reach 550 umol'inol ' by 2050. Elevation of [CO2] will invariably influence the growth and yield of mung bean. Research on the growth and uptake of C and N in mung bean in response to elevated [CO2] will benefit the study of the balance of nutrients under future climate change. This could provide the scientific basis for high-value mung bean production through the implementation of climate-oriented policies. Contrary to recent studies of crop response to elevated [CO2] in chambers and other enclosures, FACE (Free Air CO2 Enrichment) was used in this study. In the study, mung bean was planted under ambient [CO2] of 389±40 umolmor1 and FACE regimes of 55O±6O umolmol-1, respectively. The results showed that leaf, stem, pod, root, above-ground part and total biomass, and root/shoot ratio increased under elevated [CO2]. Elevated [CO2] increased the weight of leaf by I7.15%~80.20% and that of stem by 25.29%~97.38%, compared with ambient [CO2]. Under FACE, the weight of pod significantly increased by 24.50% at harvest. The weight of root increased by 34.17% and 60.41% at pod-filling and harvest stages, respectively. Elevated [CO2] Increased above-ground biomass weight by 12.90%~83.09%. Total biomass weight increased by 13.98% and 25.79% at pod-filling and harvest stages, respectively. Root/shoot ratio increased by 18.68% at pod-filling stage. N concentration in above-ground part of mung bean decreased by 10.39%~2I.06% under FACE compared with ambient [CO:]. Elevated [CO2] increased C concentration and C/N ratio by 0.41%~1.13% and 12.23%~26.68%, respectively. The change in seed N and C concentration and C/N ratio was insignificant. N and C uptake by above-ground part of mung bean increased by 1.99%~50.87% and 14.43%~92.69%, respectively. Biomass increase suggested higher crop assimilation of C and absorption of soil N under elevated [CO2] conditions. This implied that mung bean production

  6. Effects of elevated root zone CO2 and air temperature on photosynthetic gas exchange, nitrate uptake, and total reduced nitrogen content in aeroponically grown lettuce plants.

    Science.gov (United States)

    He, Jie; Austin, Paul T; Lee, Sing Kong

    2010-09-01

    maximal A and total shoot reduced N concentration of plants under different RZ [CO(2)], indicating that increased A under elevated RZ [CO(2)] could partially be due to the higher shoot total reduced N.

  7. Uncertainty of long-term CO2 flux estimates due to the choice of the spectral correction method

    Science.gov (United States)

    Ibrom, Andreas; Geißler, Simon; Pilegaard, Kim

    2010-05-01

    stable atmospheric stratification was less pronounced, resulting in less amount of correction for low-pass filtering at night time and consequently higher annual net CO2 uptake estimates. On the other hand our data indicate that the increase of fx already starts earlier than expected, i.e. during the transition from unstable to neutral stratification. We derived an empirical model of the shape of fx(?) with 4 parameters that is able to represent the observed effects. References Horst, T.W. 1997. A simple formula for attenuation of eddy fluxes measured with first-order- response scalar sensors. Boundary-Layer Meteorology. 82:219-233. Ibrom, A., E. Dellwik, N.O. Jensen, H. Flyvbjerg and K. Pilegaard 2007. Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems. Agricultural and Forest Meteorology. 147:140 -156. Acknowledgements This work has been funded by the EU-Infra structure project IMECC and the European Erasmus Mundus program. We especially thank the Risø - DTU's Wind Energy Department, namely Ebba Dellwik and Søren W. Lund, for their strong technical and scientific cooperation.

  8. Assessing Capacity Of Aspergillus Niger And Aspergillus TERREUS For Co2+, Cd2+ And Pb2+ Uptake Using Energy Dispersive X-Ray Analysis

    International Nuclear Information System (INIS)

    OUDA, S.M.

    2010-01-01

    The microbial removal of various cations could be useful for removal of toxic heavy metals from contaminated water. This study aims to investigate the uptake of metals in submerged culture of A. niger and A. terreus. The effect of Co 2+ , Cd 2+ and Pb 2+ on the fungal growth was studied in Czapek's Dox media. Maximum growth for A. niger and A. terreus was obtained at 0.01 and 0.01 - 0.1 mM/L, respectively. The concentration higher than 5 and 10 mM/L inhibited the growth, respectively. The results showed the ability of both fungal isolates to remove the three tested metals from the cultural media with percentage of removal 96.4, 95.5 and 99.98% at 1mM/L for the three metals respectively for A. niger, and it was 99.2% at 5 mM/L for Co 2+ and 97.3 and 99.9% at 1mM/L for Cd 2+ and Pb 2+ for A. terreus. The EDX analysis showed that A. niger was effective than A. terreus in accumulating Cd 2+ and Pb 2+ while both recorded low Co 2+ uptake.

  9. Embrittlement of zircaloy cladding due to oxygen uptake (CBRTTL)

    International Nuclear Information System (INIS)

    Reymann, G.A.

    1979-02-01

    A model for embrittlement of zircaloy due to oxygen uptake at high temperatures is described. The model defines limits for oxygen content and temperature which, if exceeded, give rise to zircaloy cladding which is sufficiently embrittled to cause failure either on quenching or normal handling following a transient. A significant feature of this model is that the onset of embrittlement is dependent on the cooling rate. A distinction is made between slow and fast cooling, with the boundary at 100 K/s. The material property correlations and computer subcodes described in MATPRO are developed for use in Light Water Reactor (LWR) codes

  10. Tunable rare-earth fcu-MOFs: A platform for systematic enhancement of CO2 adsorption energetics and uptake

    KAUST Repository

    Xue, Dongxu

    2013-05-22

    A series of fcu-MOFs based on rare-earth (RE) metals and linear fluorinated/nonfluorinated, homo/heterofunctional ligands were targeted and synthesized. This particular fcu-MOF platform was selected because of its unique structural characteristics combined with the ability/potential to dictate and regulate its chemical properties (e.g., tuning of the electron-rich RE metal ions and high localized charge density, a property arising from the proximal positioning of polarizing tetrazolate moieties and fluoro-groups that decorate the exposed inner surfaces of the confined conical cavities). These features permitted a systematic gas sorption study to evaluate/elucidate the effects of distinctive parameters on CO2-MOF sorption energetics. Our study supports the importance of the synergistic effect of exposed open metal sites and proximal highly localized charge density toward materials with enhanced CO2 sorption energetics. © 2013 American Chemical Society.

  11. Influences of vegetation structure and elevation on CO2 uptake in a mature jack pine forest in Saskatchewan, Canada

    International Nuclear Information System (INIS)

    Chasmer, L.; McCaughey, H.; Treitz, P.

    2008-01-01

    Eddy covariance (EC) is often used to measure the movement and direction of energy and trace gas concentrations in ecosystems. Data from EC networks are often combined with remote sensing data and ecosystem models in order to assess the spatial and temporal variability of carbon dioxide (CO 2 ) exchanges within specific areas of interest. This study presented a new method of determining changes in the structural characteristics of biomass and elevation. Lidar was used within the contours of half-hourly flux footprint areas to characterize vegetation structure and elevation. The influences of vegetation structure and elevation on CO 2 concentrations were measured by EC and Lidar measurements for 3 mature growing periods at a mature jack pine site in Saskatchewan. Mensuration data were collected over 2 periods. Meteorological, CO 2 , and H2O flux measurements were collected for 30 minute periods each day. Statistical analyses were conducted to determine the influence of meteorological variables on vegetation structure. Footprint contour lines were then layered onto the canopy height models derived by the lidar data. Multiple regression equations were used to determine net ecosystem productivity (NEP) and gross ecosystem productivity (GEP) using meteorological variables, canopy fractional cover; and elevation, as well as the results obtained from a Landsberg equation. The study showed that differences in NEP variability were influenced by differences in canopy and ground surface characteristics within the site. EC measurements underestimated gross CO 2 fluxes by 5 per cent as the biomass was lower within the immediate vicinity of the EC network. It was concluded that canopy structures and elevation are important factors for determining annual carbon balances. 36 refs., 8 tabs., 9 figs

  12. CO2 uptake and ecophysiological parameters of the grain crops of midcontinent North America: estimates from flux tower measurements

    Science.gov (United States)

    Gilmanov, Tagir; Wylie, Bruce; Tieszen, Larry; Meyers, Tilden P.; Baron, Vern S.; Bernacchi, Carl J.; Billesbach, David P.; Burba, George G.; Fischer, Marc L.; Glenn, Aaron J.; Hanan, Niall P.; Hatfield, Jerry L.; Heuer, Mark W.; Hollinger, Steven E.; Howard, Daniel M.; Matamala, Roser; Prueger, John H.; Tenuta, Mario; Young, David G.

    2013-01-01

    We analyzed net CO2 exchange data from 13 flux tower sites with 27 site-years of measurements over maize and wheat fields across midcontinent North America. A numerically robust “light-soil temperature-VPD”-based method was used to partition the data into photosynthetic assimilation and ecosystem respiration components. Year-round ecosystem-scale ecophysiological parameters of apparent quantum yield, photosynthetic capacity, convexity of the light response, respiration rate parameters, ecological light-use efficiency, and the curvature of the VPD-response of photosynthesis for maize and wheat crops were numerically identified and interpolated/extrapolated. This allowed us to gap-fill CO2 exchange components and calculate annual totals and budgets. VPD-limitation of photosynthesis was systematically observed in grain crops of the region (occurring from 20 to 120 days during the growing season, depending on site and year), determined by the VPD regime and the numerical value of the curvature parameter of the photosynthesis-VPD-response, σVPD. In 78% of the 27 site-years of observations, annual gross photosynthesis in these crops significantly exceeded ecosystem respiration, resulting in a net ecosystem production of up to 2100 g CO2 m−2 year−1. The measurement-based photosynthesis, respiration, and net ecosystem production data, as well as the estimates of the ecophysiological parameters, provide an empirical basis for parameterization and validation of mechanistic models of grain crop production in this economically and ecologically important region of North America.

  13. Simulation of anthropogenic CO2 uptake in the CCSM3.1 ocean circulation-biogeochemical model: comparison with data-based estimates

    Directory of Open Access Journals (Sweden)

    S. Khatiwala

    2012-04-01

    Full Text Available The global ocean has taken up a large fraction of the CO2 released by human activities since the industrial revolution. Quantifying the oceanic anthropogenic carbon (Cant inventory and its variability is important for predicting the future global carbon cycle. The detailed comparison of data-based and model-based estimates is essential for the validation and continued improvement of our prediction capabilities. So far, three global estimates of oceanic Cant inventory that are "data-based" and independent of global ocean circulation models have been produced: one based on the Δ C* method, and two that are based on constraining surface-to-interior transport of tracers, the TTD method and a maximum entropy inversion method (GF. The GF method, in particular, is capable of reconstructing the history of Cant inventory through the industrial era. In the present study we use forward model simulations of the Community Climate System Model (CCSM3.1 to estimate the Cant inventory and compare the results with the data-based estimates. We also use the simulations to test several assumptions of the GF method, including the assumption of constant climate and circulation, which is common to all the data-based estimates. Though the integrated estimates of global Cant inventories are consistent with each other, the regional estimates show discrepancies up to 50 %. The CCSM3 model underestimates the total Cant inventory, in part due to weak mixing and ventilation in the North Atlantic and Southern Ocean. Analyses of different simulation results suggest that key assumptions about ocean circulation and air-sea disequilibrium in the GF method are generally valid on the global scale, but may introduce errors in Cant estimates on regional scales. The GF method should also be used with caution when predicting future oceanic anthropogenic carbon uptake.

  14. Sonochemical surface functionalization of exfoliated LDH: Effect on textural properties, CO2 adsorption, cyclic regeneration capacities and subsequent gas uptake for simultaneous methanol synthesis.

    Science.gov (United States)

    Ezeh, Collins I; Huang, Xiani; Yang, Xiaogang; Sun, Cheng-Gong; Wang, Jiawei

    2017-11-01

    To improve CO 2 adsorption, amine modified Layered double hydroxide (LDH) were prepared via a two stage process, SDS/APTS intercalation was supported by ultrasonic irradiation and then followed by MEA extraction. The prepared samples were characterised using Scanning electron microscope-Energy dispersive X-ray spectroscopy (SEM-EDX), X-ray Photoelectron Spectroscopy (XPS), X-ray diffraction (XRD), Temperature Programmed Desorption (TPD), Brunauer-Emmett-Teller (BET), and Thermogravimetric analysis (TGA), respectively. The characterisation results were compared with those obtained using the conventional preparation method with consideration to the effect of sonochemical functionalization on textural properties, adsorption capacity, regeneration and lifetime of the LDH adsorbent. It is found that LDHs prepared by sonochemical modification had improved pore structure and CO 2 adsorption capacity, depending on sonic intensity. This is attributed to the enhanced deprotonation of activated amino functional groups via the sonochemical process. Subsequently, this improved the amine loading and effective amine efficiency by 60% of the conventional. In addition, the sonochemical process improved the thermal stability of the adsorbent and also, reduced the irreversible CO 2 uptake, CUirrev, from 0.18mmol/g to 0.03mmol/g. Subsequently, improving the lifetime and ease of regenerating the adsorbent respectively. This is authenticated by subjecting the prepared adsorbents to series of thermal swing adsorption (TSA) cycles until its adsorption capacity goes below 60% of the original CO 2 uptake. While the conventional adsorbent underwent a 10 TSA cycles before breaking down, the sonochemically functionalized LDH went further than 30 TSA cycles. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Environmental benefits from CO2 reduction, due to modal replacement: Case study on light rail vehicle in Brasilia City

    Energy Technology Data Exchange (ETDEWEB)

    Silva Costa, P.H. da; Alves Teixeira, L.M.; Cardoso Pinheiro, J.; Serra Arruda, F.; Mendonça Brasil, A.C.

    2016-07-01

    This work aims to measure the reduction of Carbon Dioxide (CO2) emissions in atmosphere by replacing the modal urban bus by Light Rail Vehicle (VLT). In order to accomplish this objective, a case study in Brasilia, Federal District, in the stretch of VLT which passes on Via W-3 South was conducted. The Theory of Externalities that discusses the right to ownership of private and public goods and responsibilities about the positive and negative externalities caused by the agents and individuals of society was used to support the analyses. It was used the Top-Down method, which allowed the calculation the direct emissions of CO2. The values obtained on the reduction of CO2 emissions were converted into values of carbon credits as a way to economically measure such reductions. The results showed a significant reduction in CO2 emissions per year and consequent environmental benefit. (Author)

  16. Elevated CO2 and O3 Levels Influence the Uptake and Leaf Concentration of Mineral N, P, K in Phyllostachys edulis (Carrière J.Houz. and Oligostachyum lubricum (wen King f.

    Directory of Open Access Journals (Sweden)

    Minghao Zhuang

    2018-04-01

    Full Text Available Rising CO2 and O3 concentrations significantly affect plant growth and can alter nutrient cycles. However, the effects of elevated CO2 and O3 concentrations on the nutrient dynamics of bamboo species are not well understood. In this study, using open top chambers (OTCs, we examined the effects of elevated CO2 and O3 concentrations on leaf biomass and nutrient (N, P, and K dynamics in two bamboo species, Phyllostachys edulis (Carrière J.Houz. and Oligostachyum lubricum (wen King f. Elevated O3 significantly decreased leaf biomass and nutrient uptake of both bamboo species, with the exception of no observed change in K uptake by O. lubricum. Elevated CO2 increased leaf biomass, N and K uptake of both bamboo species. Elevated CO2 and O3 simultaneously had no significant influence on leaf biomass of either species but decreased P and N uptake in P. edulis and O. lubricum, respectively, and increased K uptake in O. lubricum. The results indicate that elevated CO2 alleviated the damage caused by elevated O3 in the two bamboo species by altering the uptake of certain nutrients, which further highlights the potential interactive effects between the two gases on nutrient uptake. In addition, we found differential responses of nutrient dynamics in the two bamboo species to the two elevated gases, alone or in combination. These findings will facilitate the development of effective nutrient management strategies for sustainable management of P. edulis and O. lubricum under global change scenarios.

  17. Foraminiferal calcification and CO2

    Science.gov (United States)

    Nooijer, L. D.; Toyofuku, T.; Reichart, G. J.

    2017-12-01

    Ongoing burning of fossil fuels increases atmospheric CO2, elevates marine dissolved CO2 and decreases pH and the saturation state with respect to calcium carbonate. Intuitively this should decrease the ability of CaCO3-producing organisms to build their skeletons and shells. Whereas on geological time scales weathering and carbonate deposition removes carbon from the geo-biosphere, on time scales up to thousands of years, carbonate precipitation increases pCO2 because of the associated shift in seawater carbon speciation. Hence reduced calcification provides a potentially important negative feedback on increased pCO2 levels. Here we show that foraminifera form their calcium carbonate by active proton pumping. This elevates the internal pH and acidifies the direct foraminiferal surrounding. This also creates a strong pCO2 gradient and facilitates the uptake of DIC in the form of carbon dioxide. This finding uncouples saturation state from calcification and predicts that the added carbon due to ocean acidification will promote calcification by these organisms. This unknown effect could add substantially to atmospheric pCO2 levels, and might need to be accounted for in future mitigation strategies.

  18. Can hydrographic data provide evidence that the rate of oceanic uptake of anthropogenic CO2 is increasing?

    Directory of Open Access Journals (Sweden)

    William Carlisle Thacker

    Full Text Available Predictions of the rate of accumulation of anthropogenic carbon dioxide in the Pacific Ocean near 32°S and 150°W based on the P16 surveys of 1991 and 2005 and on the P06 surveys of 1992 and 2003 underestimate the amount found in the P06 survey of 2009-2010, suggesting an increasing uptake rate. Assuming the accumulation rate to be constant over the two decades, analyses using all five surveys lead to upward revision of the rates based only on the first four. On the other hand, accumulation rates estimated for 2003-2010 are significantly greater than those for 1991-2003, again suggesting an increasing uptake rate. In addressing this question it is important to acknowledge the limitations of the repeat hydrography and consequent uncertainties of estimated accumulation rates.

  19. Regional pattern and interannual variations in global terrestrial carbon uptake in response to changes in climate and atmospheric CO2

    International Nuclear Information System (INIS)

    Cao, Mingkui; Tao, B.; Li, Kerang; Prince, Stephen D.; Small, J.

    2005-01-01

    Atmospheric measurements indicate that the terrestrial carbon sink increased substantially from the 1980s to the 1990s, but which factors and regions were responsible for the increase are not well identified yet. Using process- and remote sensing-based ecosystem models, we show that changes in climate and atmospheric CO 2 in the period 1981-2000 enhanced net ecosystem production (NEP) and caused major geographical changes in the global distribution of NEP. In the 1980s the Americas accounted for almost all of the global NEP, but in the 1990s NEP in Eurasia and Africa became higher than that of the Americas. The year-to-year variation in global NEP was up to 2.5 Pg C (1 Pg = 10 15 g), in which 1.4 Pg C was attributable to the El Nino Southern Oscillation cycle (ENSO). NEP clearly decreased in El Nino and increased in La Nina in South America and Africa, but the response in North America and Eurasia was mixed. The estimated NEP increases accounted for only 30% of the global terrestrial carbon sink but can explain almost all of the increase from the 1980s to the 1990s. Because a large part of the increase in NEP was driven by the long-term trend of climate and atmospheric CO 2 , the increase in the global terrestrial carbon sink from the 1980s to the 1990s was a continuation of the trend since the middle of the twentieth century, rather than merely a consequence of short-time climate variability

  20. Formation of Anhydrite due to Interaction Between Water Soluble CO2 (aq) and Calcite Mineral During Enhanced Oil Recovery

    DEFF Research Database (Denmark)

    Chakravarty, Krishna Hara; Fosbøl, Philip Loldrup; Thomsen, Kaj

    2015-01-01

    In the Low Salinity based EOR method, formation and migration of fines have proved to have profound effect on the displacement efficiency of residual oil. Salinity variations of injected brines have also been shown to affect oil recovery for WAG-CO2 processes. But the effect of fines in EOR during...... simulations were conducted over a temperature range of 50°C to 250°C and a pressure range of 5 bars to 500 bars. The amounts of fines formation taking place for different LSWAG-CO2 processes were correlated to the described oil recovery. It is observed that significant amounts of fines formation can take...... with the available SO42- ions. The salinity and composition of brines present in pore space shows direct correlation with the amount of fines produced during CO2 injection. With increase in temperature and pressure, the amount fines formation increased significantly. The described oil recovery for different LSWAG...

  1. A high resolution interferometric method to measure local swelling due to CO2 exposure in coal and shale

    NARCIS (Netherlands)

    Pluymakers, A.; Liu, J.; Kohler, F.; Renard, F.; Dysthe, D.

    2018-01-01

    We present an experimental method to study time-dependent, CO2-induced, local topography changes in mm-sized composite samples, plus results showing heterogeneous swelling of coal and shale on the nano- to micrometer scale. These results were obtained using high resolution interferometry

  2. Cerebral blood flow and CO2 reactivity in transient ischemic attacks: comparison between TIAs due to the ICA occlusion and ICA mild stenosis

    International Nuclear Information System (INIS)

    Tsuda, Y.; Kimura, K.; Yoneda, S.; Etani, H.; Asai, T.; Nakamura, M.; Abe, H.

    1983-01-01

    Hemispheric mean cerebral blood flow (CBF), together with its CO2 reactivity in response to hyperventilation, was investigated in 18 patients with transient ischemic attacks (TIAs) by intraarterial 133Xe injection method in a subacute-chronic stage of the clinical course. In 8 patients, the lesion responsible for symptoms was regarded as unilateral internal carotid artery (ICA) occlusion, and in 10 patients, it was regarded as unilateral ICA mild stenosis (less than 50% stenosis in diameter). Resting flow values were significantly decreased in the affected hemisphere of TIA due to the ICA occlusion as compared with the unaffected hemisphere of the same patient, regarded as the relative control. It was not decreased in the affected hemisphere of TIA due to the ICA mild stenosis as compared with the control. With respect to the responsiveness of CBF to changes in PaCO2, it was preserved in both TIAs, due to the ICA occlusion and ICA mild stenosis. Vasoparalysis was not observed in either types of TIAs in the subacute-chronic stage. However, in the relationship of blood pressure and CO2 reactivity, expressed as delta CBF(%)/delta PaCO2, pressure-dependent CO2 reactivity as a group was observed with significance in 8 cases of TIA due to the ICA occlusion, while no such relationship was noted in 10 cases of TIA due to the ICA mild stenosis. Moreover, clinical features were different between TIAs due to the ICA occlusion and ICA mild stenosis, i.e., more typical, repeatable TIA (6.3 +/- 3.7 times) with shorter duration (less than 30 minutes) was observed in TIAs due to the ICA mild stenosis, while more prolonged, less repeatable TIA (2.4 +/- 1.4 times) was observed in TIAs due to fixed obstruction of the ICA. From these observations, two different possible mechanisms as to the pathogenesis of TIA might be expected

  3. Effect of CO2 enhancement on beech (Fagus sylvatica L. seedling root rot due to Phytophthora plurivora and Phytophthora cactorum

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2014-09-01

    Full Text Available Global climate change is associated with higher concentrations of atmospheric carbon dioxide (CO2. The ongoing changes are likely to have significant, direct or indirect effects on plant diseases caused by many biotic agents such as phytopathogenic fungi. This study results showed that increased CO2 concentration did not stimulate the growth of 1-year-old beech Fagus sylvatica L seedlings but it activated pathogenic Phytophthora species (P. plurivora and P. cactorum which caused significant reduction in the total number of fine roots as well as their length and area. The results of the greenhouse experiment indicated that pathogens once introduced into soil survived in pot soil, became periodically active (in sufficient water conditions and were able to damage beech fine roots. However, the trees mortality was not observed during the first year of experiment. DNA analyses performed on soil and beech tissue proved persistence of introduced Phytophthora isolates.

  4. Robust Hadley Circulation Changes and Increasing Global Dryness Due to CO2 Warming from CMIP-5 Model Projections

    Science.gov (United States)

    Lau, William K. M.; Kim, K. M.

    2015-01-01

    In this paper, we investigate changes in the Hadley Circulation (HC) and their connections to increased global dryness under CO2 warming from CMIP-5 model projections. We find a strengthening of the ascending branch of the HC manifested in a deep-tropics squeeze (DTS), i.e., a deepening and narrowing of the convective zone, increased high clouds, and a rise of the level of maximum meridional mass outflow in the upper troposphere (200-100 hectopascals) of the deep tropics. The DTS induces atmospheric moisture divergence, reduces tropospheric relative humidity in the tropics and subtropics, in conjunction with a widening of the subsiding branches of the HC, resulting in increased frequency of dry events in preferred geographic locations worldwide. Among water cycle parameters examined, global dryness has the highest signal-to-noise ratio. Our results provide scientific bases for inferring that the observed tend of prolonged droughts in recent decades is likely attributable to greenhouse warming.

  5. Sudden Exposure to Solar UV-B Radiation Reduces Net CO2 Uptake and Photosystem I Efficiency in Shade-Acclimated Tropical Tree Seedlings1

    Science.gov (United States)

    Krause, G. Heinrich; Grube, Esther; Virgo, Aurelio; Winter, Klaus

    2003-01-01

    Tree seedlings developing in the understory of the tropical forest have to endure short periods of high-light stress when tree-fall gaps are formed, and direct solar radiation, including substantial UV light, reaches the leaves. In experiments simulating the opening of a tree-fall gap, the response of photosynthesis in leaves of shade-acclimated seedlings (Anacardium excelsum, Virola surinamensis, and Calophyllum longifolium) to exposure to direct sunlight (for 20–50 min) was investigated in Panama (9°N). To assess the effects of solar UV-B radiation (280–320 nm), the sunlight was filtered through plastic films that selectively absorbed UV-B or transmitted the complete spectrum. The results document a strong inhibition of CO2 assimilation by sun exposure. Light-limited and light-saturated rates of photosynthetic CO2 uptake by the leaves were affected, which apparently occurred independently of a simultaneous inhibition of potential photosystem (PS) II efficiency. The ambient UV-B light substantially contributed to these effects. The photochemical capacity of PSI, measured as absorbance change at 810 nm in saturating far-red light, was not significantly affected by sun exposure of the seedlings. However, a decrease in the efficiency of P700 photooxidation by far-red light was observed, which was strongly promoted by solar UV-B radiation. The decrease in PSI efficiency may result from enhanced charge recombination in the reaction center, which might represent an incipient inactivation of PSI, but contributes to thermal dissipation of excessive light energy and thereby to photoprotection. PMID:12586898

  6. Unexpected radionuclide uptake due to calcification in muscles

    International Nuclear Information System (INIS)

    Khier, A.

    1999-01-01

    Full text: A male patient aged 27 years was injected with 1000 MBq of 99 Tc m -MDP. The patient was an active man indulging in contact sport. He presented with lower back and pelvic pain. Spot pictures were made of the pelvis, lumbar spine and femurs. Unexpected active radionuclide uptake in the muscles was seen. In the delayed static images, there was focal accumulation of tracer uptake in the muscles overlying the mid-shaft of the left femur consistent with myositis ossificans. Myositis ossificans is a benign ossifying process that is generally solitary and well circumscribed. It is most commonly found in the muscles but it may occur in other connective tissues, especially tendons and subcutaneous fat. This was presumably associated with chronic muscular injuries contracted during sports activity

  7. Growth and cesium uptake responses of Phytolacca americana Linn. and Amaranthus cruentus L. grown on cesium contaminated soil to elevated CO2 or inoculation with a plant growth promoting rhizobacterium Burkholderia sp. D54, or in combination.

    Science.gov (United States)

    Tang, Shirong; Liao, Shangqiang; Guo, Junkang; Song, Zhengguo; Wang, Ruigang; Zhou, Xiaomin

    2011-12-30

    Growth and cesium uptake responses of plants to elevated CO(2) and microbial inoculation, alone or in combination, can be explored for clean-up of contaminated soils, and this induced phytoextraction may be better than the natural process. The present study used open-top chambers to investigate combined effects of Burkholderia sp. D54 inoculation and elevated CO(2) (860 μL L(-1)) on growth and Cs uptake by Phytolacca americana and Amaranthus cruentus grown on soil spiked with various levels of Cs (0-1000 mg kg(-1)). Elevated CO(2) and bacterial inoculation, alone or in combination, significantly increased biomass production with increased magnitude, ranging from 22% to 139% for P. americana, and 14% to 254% for A. cruentus. Total tissue Cs in both plants was significantly greater for bacterial inoculation treatment singly, and combined treatments of bacterial inoculation and elevated CO(2) than for the control treatment in most cases. Regardless of CO(2) concentrations and bacterial inoculation, A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana, but they had slightly different contents of antioxidant enzymes. It is concluded that combined effects of elevated CO(2) and microbial inoculation with regard to plant ability to grow and remove radionuclides from soil can be explored for CO(2)- and microbe-assisted phytoextraction technology. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Growth and cesium uptake responses of Phytolacca americana Linn. and Amaranthus cruentus L. grown on cesium contaminated soil to elevated CO2 or inoculation with a plant growth promoting rhizobacterium Burkholderia sp. D54, or in combination

    International Nuclear Information System (INIS)

    Tang, Shirong; Liao, Shangqiang; Guo, Junkang; Song, Zhengguo; Wang, Ruigang; Zhou, Xiaomin

    2011-01-01

    Highlights: ► Elevated CO 2 and microbial inoculation, alone or in combination, significantly promoted growth of P. americana, and A. cruentus. ► Total tissue Cs in plants was significantly increased. ► A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana. ► The two plants had slightly different contents of antioxidant enzymes. ► Combined effects of elevated CO 2 and microbial inoculation can be explored for CO 2 - and microbe-assisted phytoextraction technology. - Abstract: Growth and cesium uptake responses of plants to elevated CO 2 and microbial inoculation, alone or in combination, can be explored for clean-up of contaminated soils, and this induced phytoextraction may be better than the natural process. The present study used open-top chambers to investigate combined effects of Burkholderia sp. D54 inoculation and elevated CO 2 (860 μL L −1 ) on growth and Cs uptake by Phytolacca americana and Amaranthus cruentus grown on soil spiked with various levels of Cs (0–1000 mg kg −1 ). Elevated CO 2 and bacterial inoculation, alone or in combination, significantly increased biomass production with increased magnitude, ranging from 22% to 139% for P. americana, and 14% to 254% for A. cruentus. Total tissue Cs in both plants was significantly greater for bacterial inoculation treatment singly, and combined treatments of bacterial inoculation and elevated CO 2 than for the control treatment in most cases. Regardless of CO 2 concentrations and bacterial inoculation, A. cruentus had higher tissue Cs concentration, Cs transfer factors and concentration ratios than P. americana, but they had slightly different contents of antioxidant enzymes. It is concluded that combined effects of elevated CO 2 and microbial inoculation with regard to plant ability to grow and remove radionuclides from soil can be explored for CO 2 - and microbe-assisted phytoextraction technology.

  9. Point Climat no. 32 'One billion tonnes of CO2 avoided since 2005 in Europe: half due to energy-climate policies and half due to economic context'

    International Nuclear Information System (INIS)

    Gloaguen, Olivier; Alberola, Emilie

    2013-01-01

    Among the publications of CDC Climat Research, 'Climate Briefs' presents, in a few pages, hot topics in climate change policy. This issue addresses the following points: - CO 2 emissions generated by installations covered by the EU ETS decreased by 12.3 % since 2005, i.e a decline by 2.6% per year during Phase 2 of the EU ETS while the emission cap increased by 1% per year. - The EU ETS ended Phase 2 with a surplus of 1,742 million of allowances. All sectors recorded an overall net surplus, except for the power generation and co-generation sectors. - Based on a 'business-as-usual' scenario, we estimate that around 1.1 GtCO 2 were avoided between 2005 and 2011: around 30% of the reduction was the result of a fall in manufacturing output, while around 60% of the reduction was caused by the development of renewable energy and the improvement of the energy intensity

  10. Contrasting effects of elevated CO2 on Cu and Cd uptake by different rice varieties grown on contaminated soils with two levels of metals: Implication for phytoextraction and food safety

    International Nuclear Information System (INIS)

    Li Zhongyang; Tang Shirong; Deng Xiaofang; Wang Ruigang; Song Zhengguo

    2010-01-01

    A pot experiment in six open-top chambers with two levels of CO 2 and two multi-metal contaminated soils was conducted to investigate combined effects of elevated CO 2 levels and metals (Cu and Cd) on rice. Elevated CO 2 significantly increased the total dry weight biomass of six Chinese rice by 20-108 and 32-142% for low and high levels of contaminated soils, respectively. We observed dilution/little varied phenomena in grain Cu concentration in six rice varieties grown on both contaminated soils under elevated CO 2 . We found significantly higher Cd concentrations in the parts of three rice varieties under elevated CO 2 , but lower levels for the others. Two major conclusions can be drawn from our study: (1) rice varieties with significantly increased biomass and metal uptake under elevated CO 2 exhibit greater potential for phytoextraction and (2) given expected global increases in CO 2 concentration, CO 2 -induced accumulation of metals in rice might be a component contributing to the potential health risk in the future, with Cd being a more important threat to human health than Cu.

  11. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment

    Science.gov (United States)

    Johan Uddling; Alan J. Hogg; Ronald M. Teclaw; Mary Anne. Carroll; David S. Ellsworth

    2010-01-01

    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated...

  12. Possible impacts of CO2 storage on the marine environment

    International Nuclear Information System (INIS)

    Poremski, H.J.

    2005-01-01

    This study examined the potential impacts of deep-sea carbon dioxide (CO 2 ) sequestration on the marine environment. The upper layers of oceans are currently saturated with CO 2 , while deeper ocean waters remain undersaturated. Arctic and Antarctic waters have higher uptake rates of CO 2 due to their lower temperatures. CO 2 deposited in Arctic and Antarctic waters sinks to the bottom of the ocean, and is then transported to equatorial latitudes, where stored amounts of CO 2 that are not fixed by biochemical processes will be released and enter the atmosphere again after a period of approximately 1000 years. Nearly 50 per cent of CO 2 fixation occurs as a result of phytoplankton growth, which is dependent on the availability of a range of nutrients, essential trace metals, and optimal physical conditions. Fertilization-induced CO 2 fixation in the sediments of southern oceans will result in nutrient depletion of bottom layers, which will in turn result in lower primary production levels at equatorial latitudes. Current modelling approaches to CO 2 injection assume that the injected CO 2 will dissolve in a plume extending 100 m around a riser. Retention times of several hundred years are anticipated. However, further research is needed to investigate the efficacy of CO 2 deep ocean storage technologies. Increased CO 2 uptake can also increase the formation of bicarbonate (HCO 3 ) acidification, decrease pH values, and inhibit the formation of biomass in addition to impacting on the calcification of many organisms. It was concluded that ocean storage by injection or deep storage is an untenable option at present due to the fact that the effects of excessive CO 2 in marine environments are not fully understood. 22 refs., 2 tabs

  13. EMISI CO2 TANAH AKIBAT ALIH FUNGSI LAHAN HUTAN RAWA GAMBUT DI KALIMANTAN BARAT (Soil Emissions of CO2 Due to Land Use Change of Peat Swamp Forest at West Kalimantan

    Directory of Open Access Journals (Sweden)

    Rossie Wiedya Nusantara

    2015-01-01

    Full Text Available ABSTRAK Penelitian ini bertujuan untuk menganalisis alih fungsi lahan gambut yang menyebabkan perubahan emisi CO2 tanah pada hutan rawa gambut primer (HP, hutan gambut sekunder (HS, semak belukar (SB, kebun sawit (KS, dan kebun jagung (KJ dan menganalisis pengaruh suhu dan jeluk muka air tanah (water-table depth terhadap emisi CO2 tanah. Sampel dari tiap tipe lahan diambil sebanyak lima ulangan, total sampel 25. Saat pengukuran respirasi CO2 tanah gambut dilakukan pengukuran suhu tanah dan muka air tanah. Pengukuran di lapangan dilaksanakan dua kali yaitu awal musim kemarau dan musim hujan. Hasil penelitian menunjukkan bahwa emisi CO2 tanah tertinggi dan terendah pada dua waktu pengukuran tersebut adalah pada tipe lahan KJ (6,512 ton ha-1 th-1 dan SB (1,698  ton ha-1 th-1 serta pada tipe lahan KS (6,701 ton ha-1 th-1 dan SB (3,169 ton ha-1 th-1 berturut-turut. Suhu tanah gambut tertinggi dan terendah pada dua waktu pengukuran tersebut berturut-turut adalah pada tipe lahan SB (27,78 oC dan HP (22,78 oC, dan pada tipe lahan KS (29,08 oC dan HP (26,56 oC serta jeluk muka air tanah gambut berturut-turut pada tipe lahan KJ (56,2 cm dan  SB (32,1 cm. Faktor-faktor yang menyebabkan perubahan emisi CO2 tanah gambut adalah suhu tanah, jeluk muka air tanah dan pengelolaan lahan yang menyebabkan perubahan sifat tanah gambut, seperti ketersediaan C-organik (jumlah dan kualitas bahan organik, pH tanah dan kematangan gambut. ABSTRACT This study aims to analyze peatland use change that caused changes soil emissions of CO2 at primary peat swamp forest (HP, secondary peat forest (HS, shrub (SB, oil palm plantations (KS and corn field (KJ, and to analyze the influence of temperature and water-table depth to soil emission of CO2. Soil samples were taken from each five replications that accunt for 25 samples. Simultaneously with measurement of soil respiration measuremnts soil temperature. Field measurement is carried out twice at the beginning of dry season and

  14. Enhanced Selectivity and Uptake Capacity of CO2 and Toluene Adsorption in Co0.5 M0.33 MoS4 (M= Sb or Y) Chalcogels by Impregnated Metal Salts

    KAUST Repository

    Adhiam, Fatima Abdullah Ahmed

    2017-11-17

    The synthesis of metal chalcogenide aerogels Co0.5M0.33MoS4 (M= Sb or Y) by the sol-gel method is reported. In this system, the building blocks [MoS4]2− chelated with Co2+ and (Sb3+) or (Y3+) salts in nonaqueous solvents forming amorphous networks with a gel property. The chalcogels obtained after supercritical drying have BET surface areas of 176 m2 g−1 (Co0.5Sb0.33MoS4) and 145 m2 g−1 (Co0.5Y0.33MoS4). Electron microscopy and physisorption studies reveal that the new materials are porous with wide pore size distribution and average pore width of 16 nm. These chalcogels show higher adsorption capacity of toluene vapor (Co0.5Sb0.33MoS4: 387 mg g−1) and (Co0.5Y0.33MoS4: 304 mg g−1) over cyclohexane vapor and high selectivity of CO2 over CH4 or H2, Co0.5Sb0.33MoS4 (CO2/H2: 80 and CO2/CH4: 21), Co0.5Y0.33MoS4 (CO2/H2: 27 and CO2/CH4: 15). We also demonstrated that the impregnation of various metal species like Li+, Mg2+, and Ni2+ significantly enhanced the uptake capacity and selectivity of toluene and CO2 adsorptions in the chacogels.

  15. Regional-scale brine migration along vertical pathways due to CO2 injection - Part 2: A simulated case study in the North German Basin

    Science.gov (United States)

    Kissinger, Alexander; Noack, Vera; Knopf, Stefan; Konrad, Wilfried; Scheer, Dirk; Class, Holger

    2017-06-01

    Saltwater intrusion into potential drinking water aquifers due to the injection of CO2 into deep saline aquifers is one of the hazards associated with the geological storage of CO2. Thus, in a site-specific risk assessment, models for predicting the fate of the displaced brine are required. Practical simulation of brine displacement involves decisions regarding the complexity of the model. The choice of an appropriate level of model complexity depends on multiple criteria: the target variable of interest, the relevant physical processes, the computational demand, the availability of data, and the data uncertainty. In this study, we set up a regional-scale geological model for a realistic (but not real) onshore site in the North German Basin with characteristic geological features for that region. A major aim of this work is to identify the relevant parameters controlling saltwater intrusion in a complex structural setting and to test the applicability of different model simplifications. The model that is used to identify relevant parameters fully couples flow in shallow freshwater aquifers and deep saline aquifers. This model also includes variable-density transport of salt and realistically incorporates surface boundary conditions with groundwater recharge. The complexity of this model is then reduced in several steps, by neglecting physical processes (two-phase flow near the injection well, variable-density flow) and by simplifying the complex geometry of the geological model. The results indicate that the initial salt distribution prior to the injection of CO2 is one of the key parameters controlling shallow aquifer salinization. However, determining the initial salt distribution involves large uncertainties in the regional-scale hydrogeological parameterization and requires complex and computationally demanding models (regional-scale variable-density salt transport). In order to evaluate strategies for minimizing leakage into shallow aquifers, other target

  16. Uncertainty in geochemical modelling of CO2 and calcite dissolution in NaCl solutions due to different modelling codes and thermodynamic databases

    International Nuclear Information System (INIS)

    Haase, Christoph; Dethlefsen, Frank; Ebert, Markus; Dahmke, Andreas

    2013-01-01

    Highlights: • CO 2 and calcite dissolution is calculated. • The codes PHREEQC, Geochemist’s Workbench, EQ3/6, and FactSage are used. • Comparison with Duan and Li (2008) shows lowest deviation using phreeqc.dat and wateq4f.dat. • Using Pitzer databases does not improve accurate calculations. • Uncertainty in dissolved CO 2 is largest using the geochemical models. - Abstract: A prognosis of the geochemical effects of CO 2 storage induced by the injection of CO 2 into geologic reservoirs or by CO 2 leakage into the overlaying formations can be performed by numerical modelling (non-invasive) and field experiments. Until now the research has been focused on the geochemical processes of the CO 2 reacting with the minerals of the storage formation, which mostly consists of quartzitic sandstones. Regarding the safety assessment the reactions between the CO 2 and the overlaying formations in the case of a CO 2 leakage are of equal importance as the reactions in the storage formation. In particular, limestone formations can react very sensitively to CO 2 intrusion. The thermodynamic parameters necessary to model these reactions are not determined explicitly through experiments at the total range of temperature and pressure conditions and are thus extrapolated by the simulation code. The differences in the calculated results lead to different calcite and CO 2 solubilities and can influence the safety issues. This uncertainty study is performed by comparing the computed results, applying the geochemical modelling software codes The Geochemist’s Workbench, EQ3/6, PHREEQC and FactSage/ChemApp and their thermodynamic databases. The input parameters (1) total concentration of the solution, (2) temperature and (3) fugacity are varied within typical values for CO 2 reservoirs, overlaying formations and close-to-surface aquifers. The most sensitive input parameter in the system H 2 O–CO 2 –NaCl–CaCO 3 for the calculated range of dissolved calcite and CO 2 is the

  17. Effects of CO2 enrichment on photosynthesis, growth, and nitrogen metabolism of the seagrass Zostera noltii

    Science.gov (United States)

    Alexandre, Ana; Silva, João; Buapet, Pimchanok; Björk, Mats; Santos, Rui

    2012-01-01

    Seagrass ecosystems are expected to benefit from the global increase in CO2 in the ocean because the photosynthetic rate of these plants may be Ci-limited at the current CO2 level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H+ across the membrane as in terrestrial plants. Here, we investigate the effects of CO2 enrichment on both carbon and nitrogen metabolism of the seagrass Zostera noltii in a mesocosm experiment where plants were exposed for 5 months to two experimental CO2 concentrations (360 and 700 ppm). Both the maximum photosynthetic rate (Pm) and photosynthetic efficiency (α) were higher (1.3- and 4.1-fold, respectively) in plants exposed to CO2-enriched conditions. On the other hand, no significant effects of CO2 enrichment on leaf growth rates were observed, probably due to nitrogen limitation as revealed by the low nitrogen content of leaves. The leaf ammonium uptake rate and glutamine synthetase activity were not significantly affected by increased CO2 concentrations. On the other hand, the leaf nitrate uptake rate of plants exposed to CO2-enriched conditions was fourfold lower than the uptake of plants exposed to current CO2 level, suggesting that in the seagrass Z. noltii nitrate is not cotransported with H+ as in terrestrial plants. In contrast, the activity of nitrate reductase was threefold higher in plant leaves grown at high-CO2 concentrations. Our results suggest that the global effects of CO2 on seagrass production may be spatially heterogeneous and depend on the specific nitrogen availability of each system. Under a CO2 increase scenario, the natural levels of nutrients will probably become limiting for Z. noltii. This potential limitation becomes more relevant because the expected positive effect of CO2 increase on nitrate uptake rate was not confirmed. PMID:23145346

  18. Effects of CO(2) enrichment on photosynthesis, growth, and nitrogen metabolism of the seagrass Zostera noltii.

    Science.gov (United States)

    Alexandre, Ana; Silva, João; Buapet, Pimchanok; Björk, Mats; Santos, Rui

    2012-10-01

    Seagrass ecosystems are expected to benefit from the global increase in CO(2) in the ocean because the photosynthetic rate of these plants may be C(i)-limited at the current CO(2) level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H(+) across the membrane as in terrestrial plants. Here, we investigate the effects of CO(2) enrichment on both carbon and nitrogen metabolism of the seagrass Zostera noltii in a mesocosm experiment where plants were exposed for 5 months to two experimental CO(2) concentrations (360 and 700 ppm). Both the maximum photosynthetic rate (P(m)) and photosynthetic efficiency (α) were higher (1.3- and 4.1-fold, respectively) in plants exposed to CO(2)-enriched conditions. On the other hand, no significant effects of CO(2) enrichment on leaf growth rates were observed, probably due to nitrogen limitation as revealed by the low nitrogen content of leaves. The leaf ammonium uptake rate and glutamine synthetase activity were not significantly affected by increased CO(2) concentrations. On the other hand, the leaf nitrate uptake rate of plants exposed to CO(2)-enriched conditions was fourfold lower than the uptake of plants exposed to current CO(2) level, suggesting that in the seagrass Z. noltii nitrate is not cotransported with H(+) as in terrestrial plants. In contrast, the activity of nitrate reductase was threefold higher in plant leaves grown at high-CO(2) concentrations. Our results suggest that the global effects of CO(2) on seagrass production may be spatially heterogeneous and depend on the specific nitrogen availability of each system. Under a CO(2) increase scenario, the natural levels of nutrients will probably become limiting for Z. noltii. This potential limitation becomes more relevant because the expected positive effect of CO(2) increase on nitrate uptake rate was not confirmed.

  19. 14CO2-assimilation, translocation of 14C, and 14C-carbonate uptake in different organs of spring barley plants in relation to adult-plant resistance to powdery mildew

    International Nuclear Information System (INIS)

    Hwang, B.K.; Ibenthal, W.-D.; Heitefuss, R.

    1986-01-01

    The cultivar Peruvian of spring barley, which is susceptible at all growth stages, and Asse, which exhibits adult-plant resistance to powdery mildew, were compared in 14 CO 2 assimilation, distribution of 14 C, and 14 C-carbonate uptake in different organs of healthy and infected plants. The reduction of 14 CO 2 assimilation in infected plants at the first and fourth leaf stages was greater in Peruvian than in Asse. In Peruvian, the 14 C which was fixed by the infected third leaf of plants with mildew on the lower 3 leaves remained in the third leaves with very little translocation to other parts of the plant. Infection of the lower three leaves at the fourth leaf stage reduced 14 CO 2 assimilation in noninfected fourth leaves of Asse less than that of Peruvian, but the flow of 14 C from the healthy fourth leaves into other plant parts such as leaf sheaths was markedly stimulated in Peruvian compared to Asse. Infection also reduced the uptake of 14 C-carbonate by seedling roots, the reduction being greater in Peruvian than Asse. A greater proportion of the 14 C absorbed by roots of Asse was translocated to the infected leaves than that of Peruvian. It was concluded that powdery mildew disrupted the normal pattern of photosynthesis and translocation of metabolites in a susceptible cultivar more markedly than in an adult-plant-resistant cultivar of spring barley. (author)

  20. Positive feedback between increasing atmospheric CO2 and ecosystem productivity

    Science.gov (United States)

    Gelfand, I.; Hamilton, S. K.; Robertson, G. P.

    2009-12-01

    Increasing atmospheric CO2 will likely affect both the hydrologic cycle and ecosystem productivity. Current assumptions that increasing CO2 will lead to increased ecosystem productivity and plant water use efficiency (WUE) are driving optimistic predictions of higher crop yields as well as greater availability of freshwater resources due to a decrease in evapotranspiration. The plant physiological response that drives these effects is believed to be an increase in carbon uptake either by (a) stronger CO2 gradient between the stomata and the atmosphere, or by (b) reduced CO2 limitation of enzymatic carboxylation within the leaf. The (a) scenario will lead to increased water use efficiency (WUE) in plants. However, evidence for increased WUE is mostly based on modeling studies, and experiments producing a short duration or step-wise increase in CO2 concentration (e.g. free-air CO2 enrichment). We hypothesize that the increase in atmospheric CO2 concentration is having a positive effect on ecosystem productivity and WUE. To investigate this hypothesis, we analyzed meteorological, ANPP, and soil CO2 flux datasets together with carbon isotopic ratio (13C/12C) of archived plant samples from the long term ecological research (LTER) program at Kellogg Biological Station. The datasets were collected between 1989 and 2007 (corresponding to an increase in atmospheric CO2 concentration of ~33 ppmv at Mauna Loa). Wheat (Triticum aestivum) samples taken from 1989 and 2007 show a significant decrease in the C isotope discrimination factor (Δ) over time. Stomatal conductance is directly related to Δ, and thus Δ is inversely related to plant intrinsic WUE (iWUE). Historical changes in the 13C/12C ratio (δ13C) in samples of a perennial forb, Canada goldenrod (Solidago canadensis), taken from adjacent successional fields, indicate changes in Δ upon uptake of CO2 as well. These temporal trends in Δ suggest a positive feedback between the increasing CO2 concentration in the

  1. Assessment of human health hazard due to metal uptake via fish ...

    African Journals Online (AJOL)

    Assessment of human health hazard due to metal uptake via fish consumption from coastal area of Tanzania. ... The result shows that the concentration and THQ of As in all fish samples ranges from 1.173 – 2.325 which is > 1, hence signified that a daily exposure at this level are in risk of cancer during a person lifetime.

  2. Iron availability, nitrate uptake, and exportable new production in the subarctic Pacific. [phytoplankton population growth support and atmospheric CO2 removal

    Science.gov (United States)

    Banse, Karl

    1991-01-01

    This paper presents a critique of experimental data and papers by Martin et al. (1989, 1990), who suggested that the phytoplankton growth is iron-limited and that, small additions of iron to large subarctic ocean areas might be a way of removing significant amounts of atmospheric CO2 by increasing phytoplancton growth. Data are presented to show that, in the summer of 1987, the phytoplankton assemblage as a whole was not iron limited, as measured by the bulk removal of nitrate or by the increase of chlorophyll. It is suggested that grazing normally prevents the phytoplankton from reaching concentrations that reduce the iron (and nitrate) to levels that depress division rates drastically.

  3. Incidental Diagnosis of Carcinoma of the Bladder Due to Uptake of 99mTc-MDP

    International Nuclear Information System (INIS)

    Damle, Nishikant A; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar; Subbarao, Kiran; Singh, Prabhjot; Mishra, Rohini; Das, Nitendra Lal; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar

    2012-01-01

    A bone scan was per-formed using 740 MBq (29 mCi) 99 mTc-MDP. Whole-body planar images were acquired 3 h after injection (Fig. 1). Soft tissue uptake of 99 mTc-MDP is described in various benign and malignant conditions. It is known to accumulate in adenocarcinoma of lung, primary breast cancer, and colonic carcinoma among others. The postulated causes of 99 mTc-MDP uptake in extraosseous neoplasms are numerous and include tumor vascularity, inflammation, local pH factors, altered calcium metabolism, hormonal influences and cell wall damage. Our case shows that TCC of the bladder was incidentally diagnosed due to MDP uptake in multiple bladder polyps detected on a bone scan done for low backache in an 80-year-old man

  4. CO2 Fluxes and Concentrations in a Residential Area in the Southern Hemisphere

    Science.gov (United States)

    Weissert, L. F.; Salmond, J. A.; Turnbull, J. C.; Schwendenmann, L.

    2014-12-01

    While cities are generally major sources of anthropogenic carbon dioxide (CO2) emissions, recent research has shown that parts of urban areas may also act as CO2 sinks due to CO2 uptake by vegetation. However, currently available results are related to a large degree of uncertainty due to the limitations of the applied methods and the limited number of studies available from urban areas, particularly from the southern hemisphere. In this study, we explore the potential of eddy covariance and tracer measurements (13C and 14C isotopes of CO2) to quantify and partition CO2 fluxes and concentrations in a residential urban area in Auckland, New Zealand. Based on preliminary results from autumn and winter (March to July 2014) the residential area is a small source of CO2 (0.11 mol CO2 m-2 day-1). CO2 fluxes and concentrations follow a distinct diurnal cycle with a morning peak between 7:00 and 9:00 (max: 0.25 mol CO2 m-2 day-1/412 ppm) and midday low with negative CO2 fluxes (min: -0.17 mol CO2 m-2 day-1/392 ppm) between 10:00 and 15:00 local time, likely due to photosynthetic CO2 uptake by local vegetation. Soil CO2 efflux may explain that CO2 concentrations increase and remain high (401 ppm) throughout the night. Mean diurnal winter δ13C values are in anti-phase with CO2 concentrations and vary between -9.0 - -9.7‰. The depletion of δ13C compared to clean atmospheric air (-8.2‰) is likely a result of local CO2 sources dominated by gasoline combustion (appr. 60%) during daytime. A sector analysis (based on prevailing wind) of CO2 fluxes and concentrations indicates lower CO2 fluxes and concentrations from the vegetation-dominated sector, further demonstrating the influence of vegetation on local CO2 concentrations. These results provide an insight into the temporal and spatial variability CO2 fluxes/concentrations and potential CO2 sinks and sources from a city in the southern hemisphere and add valuable information to the global database of urban CO2 fluxes.

  5. The time aspect of bioenergy. Climate impacts of bioenergy due to differences in carbon uptake rates

    Energy Technology Data Exchange (ETDEWEB)

    Zetterberg, Lars [IVL Swedish Environmental Research Institute, Stockholm (Sweden); Chen, Deliang [Dept. of Earth Sciences, Univ. of Gothenburg, Gothenburg (Sweden)

    2011-07-01

    This paper investigates the climate impacts from bioenergy due to how they influence carbon stocks over time and more specifically how fast combustion related carbon emissions are compensated by uptake of atmospheric carbon. A set of fuel types representing different uptake rates are investigated, namely willow, branches and tops, stumps and coal. Net emissions are defined as emissions from utilizing the fuel minus emissions from a reference case of no utilisation. In the case of forest residues, the compensating 'uptake' is avoided emissions from the reference case of leaving the residues to decompose on the ground. Climate impacts are estimated using the measures radiative forcing and global average surface temperature, which have been calculated by an energy balance climate model. We conclude that there is a climate impact from using bioenergy due to how fast the emission pulse is compensated by uptake of atmospheric carbon (or avoided emissions). Biofuels with slower uptake rates have a stronger climate impact than fuels with a faster uptake rate, assuming all other parameters equal. The time perspective over which the analysis is done is crucial for the climate impact of biofuels. If only biogenic fluxes are considered, our results show that over a 100 year perspective branches and tops are better for climate mitigation than stumps which in turn are better than coal. Over a 20 year time perspective this conclusion holds, but the differences between these fuels are relatively smaller. Establishing willow on earlier crop land may reduce atmospheric carbon, provided new land is available. However, these results are inconclusive since we haven't considered the effects, if needed, of producing the traditional agricultural crops elsewhere. The analysis is not a life cycle assessment of different fuels and does therefore not consider the use of fossil fuels for logging, transportation and refining, other greenhouse gases than carbon or energy

  6. From chemolithoautotrophs to electrolithoautotrophs: CO2 fixation by Fe(II)-oxidizing bacteria coupled with direct uptake of electrons from solid electron sources.

    Science.gov (United States)

    Ishii, Takumi; Kawaichi, Satoshi; Nakagawa, Hirotaka; Hashimoto, Kazuhito; Nakamura, Ryuhei

    2015-01-01

    At deep-sea vent systems, hydrothermal emissions rich in reductive chemicals replace solar energy as fuels to support microbial carbon assimilation. Until recently, all the microbial components at vent systems have been assumed to be fostered by the primary production of chemolithoautotrophs; however, both the laboratory and on-site studies demonstrated electrical current generation at vent systems and have suggested that a portion of microbial carbon assimilation is stimulated by the direct uptake of electrons from electrically conductive minerals. Here we show that chemolithoautotrophic Fe(II)-oxidizing bacterium, Acidithiobacillus ferrooxidans, switches the electron source for carbon assimilation from diffusible Fe(2+) ions to an electrode under the condition that electrical current is the only source of energy and electrons. Site-specific marking of a cytochrome aa3 complex (aa3 complex) and a cytochrome bc1 complex (bc1 complex) in viable cells demonstrated that the electrons taken directly from an electrode are used for O2 reduction via a down-hill pathway, which generates proton motive force that is used for pushing the electrons to NAD(+) through a bc1 complex. Activation of carbon dioxide fixation by a direct electron uptake was also confirmed by the clear potential dependency of cell growth. These results reveal a previously unknown bioenergetic versatility of Fe(II)-oxidizing bacteria to use solid electron sources and will help with understanding carbon assimilation of microbial components living in electronically conductive chimney habitats.

  7. Application of Ann for Prediction of Co2+, Cd2+ and Zn2+ Ions Uptake by R. Squarrosus Biomass in Single and Binary Mixtures

    Directory of Open Access Journals (Sweden)

    Nemeček Peter

    2014-06-01

    Full Text Available Discharge of heavy metals into aquatic ecosystems has become a matter of concern over the last few decades. The search for new technologies involving the removal of toxic metals from wastewaters has directed the attention to biosorption, based on metal binding capacities of various biological materials. Degree of sorbent affinity for the sorbate determines its distribution between the solid and liquid phases and this behavior can be described by adsorption isotherm models (Freundlich and Langmuir isotherm models representing the classical approach. In this study, an artificial neural network (ANN was proposed to predict the sorption efficiency in single and binary component solutions of Cd2+, Zn2+ and Co2+ ions by biosorbent prepared from biomass of moss Rhytidiadelphus squarrosus. Calculated non-linear ANN models presented in this paper are advantageous for its capability of successful prediction, which can be problematic in the case of classical isotherm approach. Quality of prediction was proved by strong agreement between calculated and measured data, expressed by the coefficient of determination in both, single and binary metal systems (R2= 0.996 and R2= 0.987, respectively. Another important benefit of these models is necessity of significantly smaller amount of data (about 50% for the model calculation. Also, it is possible to calculate Qeq for all studied metals by one combined ANN model, which totally overcomes a classical isotherm approach

  8. CO2 blood test

    Science.gov (United States)

    Bicarbonate test; HCO3-; Carbon dioxide test; TCO2; Total CO2; CO2 test - serum; Acidosis - CO2; Alkalosis - CO2 ... Many medicines can interfere with blood test results. Your health ... need to stop taking any medicines before you have this test. DO ...

  9. Airborne Hyperspectral Evaluation of Maximum Gross Photosynthesis, Gravimetric Water Content, and CO2 Uptake Efficiency of the Mer Bleue Ombrotrophic Peatland

    Directory of Open Access Journals (Sweden)

    J. Pablo Arroyo-Mora

    2018-04-01

    Full Text Available Peatlands cover a large area in Canada and globally (12% and 3% of the landmass, respectively. These ecosystems play an important role in climate regulation through the sequestration of carbon dioxide from, and the release of methane to, the atmosphere. Monitoring approaches, required to understand the response of peatlands to climate change at large spatial scales, are challenged by their unique vegetation characteristics, intrinsic hydrological complexity, and rapid changes over short periods of time (e.g., seasonality. In this study, we demonstrate the use of multitemporal, high spatial resolution (1 m2 hyperspectral airborne imagery (Compact Airborne Spectrographic Imager (CASI and Shortwave Airborne Spectrographic Imager (SASI sensors for assessing maximum instantaneous gross photosynthesis (PGmax in hummocks, and gravimetric water content (GWC and carbon uptake efficiency in hollows, at the Mer Bleue ombrotrophic bog. We applied empirical models (i.e., in situ data and spectral indices and we derived spatial and temporal trends for the aforementioned variables. Our findings revealed the distribution of hummocks (51.2%, hollows (12.7%, and tree cover (33.6%, which is the first high spatial resolution map of this nature at Mer Bleue. For hummocks, we found growing season PGmax values between 8 μmol m−2 s−1 and 12 μmol m−2 s−1 were predominant (86.3% of the total area. For hollows, our results revealed, for the first time, the spatial heterogeneity and seasonal trends for gravimetric water content and carbon uptake efficiency for the whole bog.

  10. CO2 sequestration

    International Nuclear Information System (INIS)

    Favre, E.; Jammes, L.; Guyot, F.; Prinzhofer, A.; Le Thiez, P.

    2009-01-01

    This document presents the summary of a conference-debate held at the Academie des Sciences (Paris, France) on the topic of CO 2 sequestration. Five papers are reviewed: problems and solutions for the CO 2 sequestration; observation and surveillance of reservoirs; genesis of carbonates and geological storage of CO 2 ; CO 2 sequestration in volcanic and ultra-basic rocks; CO 2 sequestration, transport and geological storage: scientific and economical perspectives

  11. Shifting terrestrial feedbacks from CO2 fertilization to global warming

    Science.gov (United States)

    Peñuelas, Josep; Ciais, Philippe; Janssens, Ivan; Canadell, Josep; Obersteiner, Michael; Piao, Shilong; Vautard, Robert; Sardans Jordi Sardans, Jordi

    2016-04-01

    Humans are increasingly fertilizing the planet. Our activities are increasing atmospheric concentrations of carbon dioxide, nitrogen inputs to ecosystems and global temperatures. Individually and combined, they lead to biospheric availability of carbon and nitrogen, enhanced metabolic activity, and longer growing seasons. Plants can consequently grow more and take up more carbon that can be stored in ecosystem carbon pools, thus enhancing carbon sinks for atmospheric CO2. Data on the increased strength of carbon sinks are, however, inconclusive: Some data (eddy covariance, short-term experiments on elevated CO2 and nutrient fertilization) suggest that biospheric carbon uptake is already effectively increasing but some other data suggest it is not, or are not general and conclusive (tree-ring, forest inventory). The combined land-ocean CO2 sink flux per unit of excess atmospheric CO2 above preindustrial levels declined over 1959-2012 by a factor of about 1/3, implying that CO2 sinks increased more slowly than excess CO2. We will discuss the available data, and the discussion will drive us to revisit our projections for enhanced carbon sinks. We will reconsider the performance of the modulators of increased carbon uptake in a CO2 fertilized and warmed world: nutrients, climate, land use and pollution. Nutrient availability in particular plays a crucial role. A simple mass-balance approach indicates that limited phosphorus availability and the corresponding N:P imbalances can jointly reduce the projected future carbon storage by natural ecosystems during this century. We then present a new paradigm: we are shifting from a fertilization to a warming era. Compared to the historical period, future impacts of warming will be larger than the benefits of CO2 fertilization given nutrient limitations, management and disturbance (which reduces C stocks and thus sequestration potential) and because CO2 will decrease by 2050 in RCP2.6, meaning loss of CO2 fertilization, and CO2

  12. When is reacquisition necessary due to high extra-cardiac uptake in myocardial perfusion scintigraphy?

    DEFF Research Database (Denmark)

    Johansen, Allan; Lomsky, Milan; Gerke, Oke

    2013-01-01

    Technetium-labeled agents, which are most often used for assessing myocardial perfusion in myocardial perfusion scintigraphy (MPS), are cleared by the liver and excreted by the biliary system. Spillover from extra-cardiac activity into the myocardium, especially the inferior wall, might conceal d...... defects and lower the diagnostic accuracy of the study. The objective was to determine rules of thumb for when reacquisition is useful due to high extra-cardiac uptake, i.e., when interpretation of the studies was affected by poor image quality....

  13. Air-ice CO2 fluxes and pCO2 dynamics in the Arctic coastal area (Amundsen Gulf, Canada)

    Science.gov (United States)

    Geilfus, Nicolas-Xavier; Tison, Jean Louis; Carnat, Gauthier; Else, Brent; Borges, Alberto V.; Thomas, Helmuth; Shadwick, Elizabeth; Delille, Bruno

    2010-05-01

    Sea ice covers about 7% of the Earth surface at its maximum seasonal extent. For decades sea ice was assumed to be an impermeable and inert barrier for air - sea exchange of CO2 so that global climate models do not include CO2 exchange between the oceans and the atmosphere in the polar regions. However, uptake of atmospheric CO2 by sea ice cover was recently reported raising the need to further investigate pCO2 dynamics in the marine cryosphere realm and related air-ice CO2 fluxes. In addition, budget of CO2 fluxes are poorly constrained in high latitudes continental shelves [Borges et al., 2006]. We report measurements of air-ice CO2 fluxes above the Canadian continental shelf and compare them to previous measurements carried out in Antarctica. We carried out measurements of pCO2 within brines and bulk ice, and related air-ice CO2 fluxes (chamber method) in Antarctic first year pack ice ("Sea Ice Mass Balance in Antarctica -SIMBA" drifting station experiment September - October 2007) and in Arctic first year land fast ice ("Circumpolar Flaw Lead" - CFL, April - June 2008). These 2 experiments were carried out in contrasted sites. SIMBA was carried out on sea ice in early spring while CFL was carried out in from the middle of the winter to the late spring while sea ice was melting. Both in Arctic and Antarctic, no air-ice CO2 fluxes were detected when sea ice interface was below -10°C. Slightly above -10°C, fluxes toward the atmosphere were observed. In contrast, at -7°C fluxes from the atmosphere to the ice were significant. The pCO2 of the brine exhibits a same trend in both hemispheres with a strong decrease of the pCO2 anti-correlated with the increase of sea ice temperature. The pCO2 shifted from a large over-saturation at low temperature to a marked under-saturation at high temperature. These air-ice CO2 fluxes are partly controlled by the permeability of the air-ice interface, which depends of the temperature of this one. Moreover, air-ice CO2 fluxes are

  14. Manipulative lowering of the water table during summer does not affect CO2 emissions and uptake in a fen in Germany.

    Science.gov (United States)

    Muhr, Jan; Höhle, Juliane; Otieno, Dennis O; Borken, Werner

    2011-03-01

    We simulated the effect of prolonged dry summer periods by lowering the water table on three manipulation plots (D(1-3)) in a minerotrophic fen in southeastern Germany in three years (2006-2008). The water table at this site was lowered by drainage and by excluding precipitation; three nonmanipulated control plots (C(1-3)) served as a reference. We found no significant differences in soil respiration (R(Soil)), gross primary production (GPP), or aboveground respiration (R(AG)) between the C(1-3) and D(1-3) plots in any of the measurement years. The water table on the control plots was naturally low, with a median water table (2006-2008) of 8 cm below the surface, and even lower during summer when respiratory activity was highest, with median values (C(1-3)) between 11 and 19 cm below the surface. If it is assumed that oxygen availability in the uppermost 10 cm was not limited by the location of the water table, manipulative lowering of the water table most likely increased oxygen availability only in deeper peat layers where we expect R(Soil) to be limited by poor substrate quality rather than anoxia. This could explain the lack of a manipulation effect. In a second approach, we estimated the influence of the water table on R(Soil) irrespective of treatment. The results showed a significant correlation between R(Soil) and water table, but with R(Soil) decreasing at lower water tables rather than increasing. We thus conclude that decomposition in the litter layer is not limited by waterlogging in summer, and deeper peat layers bear no significant decomposition potential due to poor substrate quality. Consequently, we do not expect enhanced C losses from this site due to increasing frequency of dry summers. Assimilation and respiration of aboveground vegetation were not affected by water table fluctuations between 10 and >60 cm depth, indicating the lack of stress resulting from either anoxia (high water table) or drought (low water table).

  15. CO2 Losses from Terrestrial Organic Matter through Photodegradation

    Science.gov (United States)

    Rutledge, S.; Campbell, D. I.; Baldocchi, D. D.; Schipper, L. A.

    2010-12-01

    Net ecosystem exchange (NEE) is the sum of CO2 uptake by plants and CO2 losses from both living plants and dead organic matter. In all but a few ecosystem scale studies on terrestrial carbon cycling, losses of CO2 from dead organic matter are assumed to be the result of microbial respiration alone. Here we provide evidence for an alternative, previously largely underestimated mechanism for ecosystem-scale CO2 emissions. The process of photodegradation, the direct breakdown of organic matter by solar radiation, was found to contribute substantially to the ecosystem scale CO2 losses at both a bare peatland in New Zealand, and a summer-dead grassland in California. Comparisons of daytime eddy covariance (EC) data with data collected at the same time using an opaque chamber and the CO2 soil gradient technique, or with night-time EC data collected during similar moisture and temperature conditions were used to quantify the direct effect of exposure of organic matter to solar radiation. At a daily scale, photodegradation contributed up to 62% and 92% of summer mid-day CO2 fluxes at the de-vegetated peatland and at the grassland during the dry season, respectively. Irradiance-induced CO2 losses were estimated to be 19% of the total annual CO2 loss at the peatland, and almost 60% of the dry season CO2 loss at the grassland. Small-scale measurements using a transparent chamber confirmed that CO2 emissions from air-dried peat and grass occurred within seconds of exposure to light when microbial activity was inhibited. Our findings imply that photodegradation could be important for many ecosystems with exposed soil organic matter, litter and/or standing dead material. Potentially affected ecosystems include sparsely vegetated arid and semi-arid ecosystems (e.g. shrublands, savannahs and other grasslands), bare burnt areas, agricultural sites after harvest or cultivation (especially if crop residues are left on the surface), deciduous forests after leaf fall, or ecosystems

  16. CO_2 capture from flue gas using clathrate formation in the presence of thermodynamic promoters

    International Nuclear Information System (INIS)

    Kim, Soyoung; Choi, Sung-Deuk; Seo, Yongwon

    2017-01-01

    Tetrahydrofuran (THF) as a water-soluble sII clathrate former, cyclopentane (CP) as a water-insoluble sII clathrate former, and tetra n-butyl ammonium chloride (TBAC) as a water-soluble semiclathrate former were used to investigate their thermodynamic promotion effects on clathrate-based CO_2 capture from simulated flue gas. The phase equilibria of CO_2 (20%) + N_2 (80%) + promoter clathrates at different promoter concentrations revealed that the presence of THF, CP, and TBAC could significantly reduce the clathrate formation pressure. THF solutions provided the highest gas uptake and steepest CO_2 concentration changes in the vapor phase, whereas TBAC solutions showed the highest CO_2 selectivity (∼61%) in the clathrate phase. CP solutions exhibited a slower formation rate, but their final gas uptake and CO_2 selectivity in the clathrate phase were comparable to the THF solutions. Raman spectroscopy confirmed the enclathration of both CO_2 and N_2 in the clathrate cages and a structural transition due to the inclusion of promoters in the clathrate phase. The overall experimental results indicate that TBAC is a viable thermodynamic promoter for clathrate-based CO_2 capture from simulated flue gas, considering the lower pressure requirement for clathrate formation, higher CO_2 enrichment in the clathrate phase, non-toxicity, and non-volatility. - Highlights: • Clathrate-based CO_2 capture was investigated in the presence of thermodynamic promoters. • THF, CP, and TBAC demonstrated a significant thermodynamic promotion for CO_2 (20%) + N_2 (80%) clathrates. • The highest gas uptake was observed for the THF (5.6 mol%) solution. • TBAC solutions showed the highest CO_2 selectivity in the clathrate phase (∼61%). • Raman spectroscopy confirmed the guest gas enclathration and clathrate structure.

  17. CaO-Based CO2 Sorbents Effectively Stabilized by Metal Oxides.

    Science.gov (United States)

    Naeem, Muhammad Awais; Armutlulu, Andac; Imtiaz, Qasim; Müller, Christoph R

    2017-11-17

    Calcium looping (i.e., CO 2 capture by CaO) is a promising second-generation CO 2 capture technology. CaO, derived from naturally occurring limestone, offers an inexpensive solution, but due to the harsh operating conditions of the process, limestone-derived sorbents undergo a rapid capacity decay induced by the sintering of CaCO 3 . Here, we report a Pechini method to synthesize cyclically stable, CaO-based CO 2 sorbents with a high CO 2 uptake capacity. The sorbents synthesized feature compositional homogeneity in combination with a nanostructured and highly porous morphology. The presence of a single (Al 2 O 3 or Y 2 O 3 ) or bimetal oxide (Al 2 O 3 -Y 2 O 3 ) provides cyclic stability, except for MgO which undergoes a significant increase in its particle size with the cycle number. We also demonstrate a direct relationship between the CO 2 uptake and the morphology of the synthesized sorbents. After 30 cycles of calcination and carbonation, the best performing sorbent, containing an equimolar mixture of Al 2 O 3 and Y 2 O 3 , exhibits a CO 2 uptake capacity of 8.7 mmol CO 2  g -1 sorbent, which is approximately 360 % higher than that of the reference limestone. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. CO2NNIE

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2015-01-01

    We propose a system for calculating the personalized annual fuel consumption and CO2 emissions from transportation. The system, named CO2NNIE, estimates the fuel consumption on the fastest route between the frequent destinations of the user. The travel time and fuel consumption estimated are based......% of the actual fuel consumption (4.6% deviation on average). We conclude, that the system provides new detailed information on CO2 emissions and fuel consumption for any make and model....

  19. The role of vegetation in the CO2 flux from a tropical urban neighbourhood

    Science.gov (United States)

    Velasco, E.; Roth, M.; Tan, S. H.; Quak, M.; Nabarro, S. D. A.; Norford, L.

    2013-03-01

    Urban surfaces are usually net sources of CO2. Vegetation can potentially have an important role in reducing the CO2 emitted by anthropogenic activities in cities, particularly when vegetation is extensive and/or evergreen. Negative daytime CO2 fluxes, for example have been observed during the growing season at suburban sites characterized by abundant vegetation and low population density. A direct and accurate estimation of carbon uptake by urban vegetation is difficult due to the particular characteristics of the urban ecosystem and high variability in tree distribution and species. Here, we investigate the role of urban vegetation in the CO2 flux from a residential neighbourhood in Singapore using two different approaches. CO2 fluxes measured directly by eddy covariance are compared with emissions estimated from emissions factors and activity data. The latter includes contributions from vehicular traffic, household combustion, soil respiration and human breathing. The difference between estimated emissions and measured fluxes should approximate the biogenic flux. In addition, a tree survey was conducted to estimate the annual CO2 sequestration using allometric equations and an alternative model of the metabolic theory of ecology for tropical forests. Palm trees, banana plants and turfgrass were also included in the survey with their annual CO2 uptake obtained from published growth rates. Both approaches agree within 2% and suggest that vegetation captures 8% of the total emitted CO2 in the residential neighbourhood studied. A net uptake of 1.4 ton km-2 day-1 (510 ton km-2 yr-1 ) was estimated from the difference between the daily CO2 uptake by photosynthesis (3.95 ton km-2 ) and release by respiration (2.55 ton km-2). The study shows the importance of urban vegetation at the local scale for climate change mitigation in the tropics.

  20. Isotopic versus micrometeorologic ocean CO2 fluxes: A serious conflict

    International Nuclear Information System (INIS)

    Broecker, W.S.; Ledwell, J.R.; Takahashi, T.; Weiss, R.; Merlivat, L.; Memery, L.; Tsung-Hung Peng; Jahne, B.; Otto Munnich, K.

    1986-01-01

    Eddy correlation measurements over the ocean give CO 2 fluxes an order of magnitude or more larger than expected from mass balance or more larger than expected from mass balance measurements using radiocarbon and radon 222. In particular, Smith and Jones (1985) reported large upward and downward fluxes in a surf zone at supersaturations of 15% and attributed them to the equilibration of bubbles at elevated pressures. They argue that even on the open ocean such bubble injection may create steady state CO 2 supersaturations and that inferences of fluxes based on air-sea pCO 2 differences and radon exchange velocities must be made with caution. We defend the global average CO 2 exchange rate determined by three independent radioisotopic means: prebomb radiocarbon inventories; global surveys of mixed layer radon deficits; and oceanic uptake of bomb-produced radiocarbon. We argue that laboratory and lake data do not lead one to expect fluxes as large as reported from the eddy correlation technique; that the radon method of determining exchange velocities is indeed useful for estimating CO 2 fluxes; that supersaturations of CO 2 due to bubble injection on the open ocean are negligible; that the hypothesis that Smith and Jones advance cannot account for the fluxes that they report; and that the pCO 2 values reported by Smith and Jones are likely to be systematically much too high. The CO 2 fluxes for the ocean measured to data by the micrometeorological method can be reconciled with neither the observed concentrations of radioisotopes of radon and carbon in the oceans nor the tracer experiments carried out in lakes and in wind/wave tunnels

  1. CO2-laser fusion

    International Nuclear Information System (INIS)

    Stark, E.E. Jr.

    1978-01-01

    The basic concept of laser fusion is described, with a set of requirements on the laser system. Systems and applications concepts are presented and discussed. The CO 2 laser's characteristics and advantages for laser fusion are described. Finally, technological issues in the development of CO 2 laser systems for fusion applications are discussed

  2. CO2 induced growth response in a diatom dominated phytoplankton community from SW Bay of Bengal coastal water

    Science.gov (United States)

    Biswas, Haimanti; Shaik, Aziz Ur Rahman; Bandyopadhyay, Debasmita; Chowdhury, Neha

    2017-11-01

    The ongoing increase in surface seawater CO2 level could potentially impact phytoplankton primary production in coastal waters; however, CO2 sensitivity studies on tropical coastal phytoplankton assemblages are rare. The present study investigated the interactive impacts of variable CO2 level, light and zinc (Zn) addition on the diatom dominated phytoplankton assemblages from the western coastal Bay of Bengal. Increased CO2 supply enhanced particulate organic matter (POC) production; a concomitant depletion in δ13CPOM values at elevated CO2 suggested increased CO2 diffusive influx inside the cell. Trace amount of Zn added under low CO2 level accelerated growth probably by accelerating Zn-Carbonic Anhydrase activity which helps in converting bicarbonate ion to CO2. Almost identical values of δ13CPOM in the low CO2 treated cells grown with and without Zn indicated a low discrimination between 13C and 12C probably due to bicarbonate uptake. These evidences collectively indicated the existence of the carbon concentration mechanisms (CCMs) at low CO2. A minimum growth rate was observed at low CO2 and light limited condition indicating light dependence of CCMs activity. Upon the increase of light and CO2 level, growth response was maximum. The cells grown in the low CO2 levels showed higher light stress (higher values of both diatoxanthin index and the ratio of photo-protective to light-harvesting pigments) that was alleviated by both increasing CO2 supply and Zn addition (probably by efficient light energy utilization in presence of adequate CO2). This is likely that the diatom dominated phytoplankton communities benefited from the increasing CO2 supply and thus may enhance primary production in response to any further increase in coastal water CO2 levels and can have large biogeochemical consequences in the study area.

  3. Outsourcing CO2 Emissions

    Science.gov (United States)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  4. Residual CO2 trapping in Indiana limestone.

    Science.gov (United States)

    El-Maghraby, Rehab M; Blunt, Martin J

    2013-01-02

    We performed core flooding experiments on Indiana limestone using the porous plate method to measure the amount of trapped CO(2) at a temperature of 50 °C and two pressures: 4.2 and 9 MPa. Brine was mixed with CO(2) for equilibration, then the mixture was circulated through a sacrificial core. Porosity and permeability tests conducted before and after 884 h of continuous core flooding confirmed negligible dissolution. A trapping curve for supercritical (sc)CO(2) in Indiana showing the relationship between the initial and residual CO(2) saturations was measured and compared with that of gaseous CO(2). The results were also compared with scCO(2) trapping in Berea sandstone at the same conditions. A scCO(2) residual trapping end point of 23.7% was observed, indicating slightly less trapping of scCO(2) in Indiana carbonates than in Berea sandstone. There is less trapping for gaseous CO(2) (end point of 18.8%). The system appears to be more water-wet under scCO(2) conditions, which is different from the trend observed in Berea; we hypothesize that this is due to the greater concentration of Ca(2+) in brine at higher pressure. Our work indicates that capillary trapping could contribute to the immobilization of CO(2) in carbonate aquifers.

  5. CO2 chemical valorization

    International Nuclear Information System (INIS)

    Kerlero De Rosbo, Guillaume; Rakotojaona, Loic; Bucy, Jacques de; Clodic, Denis; Roger, Anne-Cecile; El Khamlichi, Aicha; Thybaud, Nathalie; Oeser, Christian; Forti, Laurent; Gimenez, Michel; Savary, David; Amouroux, Jacques

    2014-07-01

    Facing global warming, different technological solutions exist to tackle carbon dioxide (CO 2 ) emissions. Some inevitable short term emissions can be captured so as to avoid direct emissions into the atmosphere. This CO 2 must then be managed and geological storage seems to currently be the only way of dealing with the large volumes involved. However, this solution faces major economic profitability and societal acceptance challenges. In this context, alternative pathways consisting in using CO 2 instead of storing it do exist and are generating growing interest. This study ordered by the French Environment and Energy Management Agency (ADEME), aims at taking stock of the different technologies used for the chemical conversion of CO 2 in order to have a better understanding of their development potential by 2030, of the conditions in which they could be competitive and of the main actions to be implemented in France to foster their emergence. To do this, the study was broken down into two main areas of focus: The review and characterization of the main CO 2 chemical conversion routes for the synthesis of basic chemical products, energy products and inert materials. This review includes a presentation of the main principles underpinning the studied routes, a preliminary assessment of their performances, advantages and drawbacks, a list of the main R and D projects underway, a focus on emblematic projects as well as a brief analysis of the markets for the main products produced. Based on these elements, 3 routes were selected from among the most promising by 2030 for an in-depth modelling and assessment of their energy, environmental and economic performances. The study shows that the processes modelled do have favorable CO 2 balances (from 1 to 4 t-CO 2 /t-product) and effectively constitute solutions to reduce CO 2 emissions, despite limited volumes of CO 2 in question. Moreover, the profitability of certain solutions will remain difficult to reach, even with an

  6. Simulating the integrated summertime Δ14CO2 signature from anthropogenic emissions over Western Europe

    Directory of Open Access Journals (Sweden)

    D. Bozhinova

    2014-07-01

    Full Text Available Radiocarbon dioxide (14CO2, reported in Δ14CO2 can be used to determine the fossil fuel CO2 addition to the atmosphere, since fossil fuel CO2 no longer contains any 14C. After the release of CO2 at the source, atmospheric transport causes dilution of strong local signals into the background and detectable gradients of Δ14CO2 only remain in areas with high fossil fuel emissions. This fossil fuel signal can moreover be partially masked by the enriching effect that anthropogenic emissions of 14CO2 from the nuclear industry have on the atmospheric Δ14CO2 signature. In this paper, we investigate the regional gradients in 14CO2 over the European continent and quantify the effect of the emissions from nuclear industry. We simulate the emissions and transport of fossil fuel CO2 and nuclear 14CO2 for Western Europe using the Weather Research and Forecast model (WRF-Chem for a period covering 6 summer months in 2008. We evaluate the expected CO2 gradients and the resulting Δ14CO2 in simulated integrated air samples over this period, as well as in simulated plant samples. We find that the average gradients of fossil fuel CO2 in the lower 1200 m of the atmosphere are close to 15 ppm at a 12 km × 12 km horizontal resolution. The nuclear influence on Δ14CO2 signatures varies considerably over the domain and for large areas in France and the UK it can range from 20 to more than 500% of the influence of fossil fuel emissions. Our simulations suggest that the resulting gradients in Δ14CO2 are well captured in plant samples, but due to their time-varying uptake of CO2, their signature can be different with over 3‰ from the atmospheric samples in some regions. We conclude that the framework presented will be well-suited for the interpretation of actual air and plant 14CO2 samples.

  7. CO2 cycle

    Science.gov (United States)

    Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

    2017-01-01

    This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

  8. Hopewell Beneficial CO2 Capture for Production of Fuels, Fertilizer and Energy

    Energy Technology Data Exchange (ETDEWEB)

    UOP; Honeywell Resins & Chemicals; Honeywell Process Solutions; Aquaflow Bionomics Ltd

    2010-09-30

    For Phase 1 of this project, the Hopewell team developed a detailed design for the Small Scale Pilot-Scale Algal CO2 Sequestration System. This pilot consisted of six (6) x 135 gallon cultivation tanks including systems for CO2 delivery and control, algal cultivation, and algal harvesting. A feed tank supplied Hopewell wastewater to the tanks and a receiver tank collected the effluent from the algal cultivation system. The effect of environmental parameters and nutrient loading on CO2 uptake and sequestration into biomass were determined. Additionally the cost of capturing CO2 from an industrial stack emission at both pilot and full-scale was determined. The engineering estimate evaluated Amine Guard technology for capture of pure CO2 and direct stack gas capture and compression. The study concluded that Amine Guard technology has lower lifecycle cost at commercial scale, although the cost of direct stack gas capture is lower at the pilot scale. Experiments conducted under high concentrations of dissolved CO2 did not demonstrate enhanced algae growth rate. This result suggests that the dissolved CO2 concentration at neutral pH was already above the limiting value. Even though dissolved CO2 did not show a positive effect on biomass growth, controlling its value at a constant set-point during daylight hours can be beneficial in an algae cultivation stage with high algae biomass concentration to maximize the rate of CO2 uptake. The limited enhancement of algal growth by CO2 addition to Hopewell wastewater was due at least in part to the high endogenous CO2 evolution from bacterial degradation of dissolved organic carbon present at high levels in the wastewater. It was found that the high level of bacterial activity was somewhat inhibitory to algal growth in the Hopewell wastewater. The project demonstrated that the Honeywell automation and control system, in combination with the accuracy of the online pH, dissolved O2, dissolved CO2, turbidity, Chlorophyll A and

  9. Modeling of CO2 storage in aquifers

    International Nuclear Information System (INIS)

    Savioli, Gabriela B; Santos, Juan E

    2011-01-01

    Storage of CO 2 in geological formations is a means of mitigating the greenhouse effect. Saline aquifers are a good alternative as storage sites due to their large volume and their common occurrence in nature. The first commercial CO 2 injection project is that of the Sleipner field in the Utsira Sand aquifer (North Sea). Nevertheless, very little was known about the effectiveness of CO 2 sequestration over very long periods of time. In this way, numerical modeling of CO 2 injection and seismic monitoring is an important tool to understand the behavior of CO 2 after injection and to make long term predictions in order to prevent CO 2 leaks from the storage into the atmosphere. The description of CO 2 injection into subsurface formations requires an accurate fluid-flow model. To simulate the simultaneous flow of brine and CO 2 we apply the Black-Oil formulation for two phase flow in porous media, which uses the PVT data as a simplified thermodynamic model. Seismic monitoring is modeled using Biot's equations of motion describing wave propagation in fluid-saturated poroviscoelastic solids. Numerical examples of CO 2 injection and time-lapse seismics using data of the Utsira formation show the capability of this methodology to monitor the migration and dispersal of CO 2 after injection.

  10. Left is right and right is wrong: fluorodeoxyglucose uptake in left hemi-diaphragm due to right phrenic nerve palsy

    International Nuclear Information System (INIS)

    Joshi, Prathamesh; Lele, Vikram

    2013-01-01

    A 36-year-old Indian man, a recently diagnosed case of the right lung carcinoma underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) for staging of the malignancy. PET/CT showed increased FDG uptake in the right lung mass, consistent with the known primary tumor. Right hemidiaphragm was found to be elevated on CT, suggesting right diaphragmatic paresis. The PET scan demonstrated asymmetric, intense FDG uptake in the left hemidiaphragm and accessory muscles of respiration, which was possibly due to compensatory increased workload related to contralateral right diaphragmatic paresis. The right diaphragmatic paresis was hypothesized to be caused by phrenic nerve palsy by right lung neoplasm. (author)

  11. Left is right and right is wrong: Fluorodeoxyglucose uptake in left hemi-diaphragm due to right phrenic nerve palsy.

    Science.gov (United States)

    Joshi, Prathamesh; Lele, Vikram

    2013-01-01

    A 36-year-old Indian man, a recently diagnosed case of the right lung carcinoma underwent fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) for staging of the malignancy. PET/CT showed increased FDG uptake in the right lung mass, consistent with the known primary tumor. Right hemidiaphragm was found to be elevated on CT, suggesting right diaphragmatic paresis. The PET scan demonstrated asymmetric, intense FDG uptake in the left hemidiaphragm and accessory muscles of respiration, which was possibly due to compensatory increased workload related to contralateral right diaphragmatic paresis. The right diaphragmatic paresis was hypothesized to be caused by phrenic nerve palsy by right lung neoplasm.

  12. Quantifying the drivers of ocean-atmosphere CO2 fluxes

    Science.gov (United States)

    Lauderdale, Jonathan M.; Dutkiewicz, Stephanie; Williams, Richard G.; Follows, Michael J.

    2016-07-01

    A mechanistic framework for quantitatively mapping the regional drivers of air-sea CO2 fluxes at a global scale is developed. The framework evaluates the interplay between (1) surface heat and freshwater fluxes that influence the potential saturated carbon concentration, which depends on changes in sea surface temperature, salinity and alkalinity, (2) a residual, disequilibrium flux influenced by upwelling and entrainment of remineralized carbon- and nutrient-rich waters from the ocean interior, as well as rapid subduction of surface waters, (3) carbon uptake and export by biological activity as both soft tissue and carbonate, and (4) the effect on surface carbon concentrations due to freshwater precipitation or evaporation. In a steady state simulation of a coarse-resolution ocean circulation and biogeochemistry model, the sum of the individually determined components is close to the known total flux of the simulation. The leading order balance, identified in different dynamical regimes, is between the CO2 fluxes driven by surface heat fluxes and a combination of biologically driven carbon uptake and disequilibrium-driven carbon outgassing. The framework is still able to reconstruct simulated fluxes when evaluated using monthly averaged data and takes a form that can be applied consistently in models of different complexity and observations of the ocean. In this way, the framework may reveal differences in the balance of drivers acting across an ensemble of climate model simulations or be applied to an analysis and interpretation of the observed, real-world air-sea flux of CO2.

  13. Corn residue removal and CO2 emissions

    Science.gov (United States)

    Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are the primary greenhouse gases (GHG) emitted from the soil due to agricultural activities. In the short-term, increases in CO2 emissions indicate increased soil microbial activity. Soil micro-organisms decompose crop residues and release...

  14. CO2-strategier

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard

    2008-01-01

    I 2007 henvendte Lyngby-Taarbæk kommunens Agenda 21 koordinator sig til Videnskabsbutikken og spurgte om der var interesse for at samarbejde om CO2-strategier. Da Videnskabsbutikken DTU er en åben dør til DTU for borgerne og deres organisationer, foreslog Videnskabsbutikken DTU at Danmarks...

  15. Porous Organic Polymers for CO2 Capture

    KAUST Repository

    Teng, Baiyang

    2013-05-01

    Carbon dioxide (CO2) has long been regarded as the major greenhouse gas, which leads to numerous negative effects on global environment. The capture and separation of CO2 by selective adsorption using porous materials proves to be an effective way to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs with high CO2 adsorption capacities and CO2/N2 selectivities for post-combustion effluent (e.g. flue gas) treatment. We will also exploit the correlation between the CO2 capture performance of POPs and their textual properties/functionalities. Chapters Two focuses on the study of a group of porous phenolic-aldehyde polymers (PPAPs) synthesized by a catalyst-free method, the CO2 capture capacities of these PPAPs exceed 2.0 mmol/g at 298 K and 1 bar, while keeping CO2/N2 selectivity of more than 30 at the same time. Chapter Three reports the gas adsorption results of different hyper-cross-linked polymers (HCPs), which indicate that heterocyclo aromatic monomers can greatly enhance polymers’ CO2/N2 selectivities, and the N-H bond is proved to the active CO2 adsorption center in the N-contained (e.g. pyrrole) HCPs, which possess the highest selectivities of more than 40 at 273 K when compared with other HCPs. Chapter Four emphasizes on the chemical modification of a new designed polymer of intrinsic microporosity (PIM) with high CO2/N2 selectivity (50 at 273 K), whose experimental repeatability and chemical stability prove excellent. In Chapter Five, we demonstrate an improvement of both CO2 capture capacity and CO2/N2 selectivity by doping alkali metal ions into azo-polymers, which leads a promising method to the design of new porous organic polymers.

  16. CO2-neutral fuels

    Directory of Open Access Journals (Sweden)

    Goede A. P. H.

    2015-01-01

    Full Text Available The need for storage of renewable energy (RE generated by photovoltaic, concentrated solar and wind arises from the fact that supply and demand are ill-matched both geographically and temporarily. This already causes problems of overcapacity and grid congestion in countries where the fraction of RE exceeds the 20% level. A system approach is needed, which focusses not only on the energy source, but includes conversion, storage, transport, distribution, use and, last but not least, the recycling of waste. Furthermore, there is a need for more flexibility in the energy system, rather than relying on electrification, integration with other energy systems, for example the gas network, would yield a system less vulnerable to failure and better adapted to requirements. For example, long-term large-scale storage of electrical energy is limited by capacity, yet needed to cover weekly to seasonal demand. This limitation can be overcome by coupling the electricity net to the gas system, considering the fact that the Dutch gas network alone has a storage capacity of 552 TWh, sufficient to cover the entire EU energy demand for over a month. This lecture explores energy storage in chemicals bonds. The focus is on chemicals other than hydrogen, taking advantage of the higher volumetric energy density of hydrocarbons, in this case methane, which has an approximate 3.5 times higher volumetric energy density. More importantly, it allows the ready use of existing gas infrastructure for energy storage, transport and distribution. Intermittent wind electricity generated is converted into synthetic methane, the Power to Gas (P2G scheme, by splitting feedstock CO2 and H2O into synthesis gas, a mixture of CO and H2. Syngas plays a central role in the synthesis of a range of hydrocarbon products, including methane, diesel and dimethyl ether. The splitting is accomplished by innovative means; plasmolysis and high-temperature solid oxygen electrolysis. A CO2-neutral fuel

  17. Incidental Diagnosis of Carcinoma of the Bladder Due to Uptake of {sup 99m}Tc-MDP

    Energy Technology Data Exchange (ETDEWEB)

    Damle, Nishikant A; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar; Subbarao, Kiran; Singh, Prabhjot [All India Institute of Medical Sciences, New Delhi (India); Mishra, Rohini; Das, Nitendra Lal; Pandey, Dinesh Chand; Gautam, Awadhesh Kumar [B. L. Kapur Memorial Hospital, New Delhi (India)

    2012-06-15

    A bone scan was per-formed using 740 MBq (29 mCi) {sup 99}mTc-MDP. Whole-body planar images were acquired 3 h after injection (Fig. 1). Soft tissue uptake of {sup 99}mTc-MDP is described in various benign and malignant conditions. It is known to accumulate in adenocarcinoma of lung, primary breast cancer, and colonic carcinoma among others. The postulated causes of {sup 99}mTc-MDP uptake in extraosseous neoplasms are numerous and include tumor vascularity, inflammation, local pH factors, altered calcium metabolism, hormonal influences and cell wall damage. Our case shows that TCC of the bladder was incidentally diagnosed due to MDP uptake in multiple bladder polyps detected on a bone scan done for low backache in an 80-year-old man.

  18. Re-evaluating the 1940s CO2 plateau

    Science.gov (United States)

    Bastos, Ana; Ciais, Philippe; Barichivich, Jonathan; Bopp, Laurent; Brovkin, Victor; Gasser, Thomas; Peng, Shushi; Pongratz, Julia; Viovy, Nicolas; Trudinger, Cathy M.

    2016-09-01

    The high-resolution CO2 record from Law Dome ice core reveals that atmospheric CO2 concentration stalled during the 1940s (so-called CO2 plateau). Since the fossil-fuel emissions did not decrease during the period, this stalling implies the persistence of a strong sink, perhaps sustained for as long as a decade or more. Double-deconvolution analyses have attributed this sink to the ocean, conceivably as a response to the very strong El Niño event in 1940-1942. However, this explanation is questionable, as recent ocean CO2 data indicate that the range of variability in the ocean sink has been rather modest in recent decades, and El Niño events have generally led to higher growth rates of atmospheric CO2 due to the offsetting terrestrial response. Here, we use the most up-to-date information on the different terms of the carbon budget: fossil-fuel emissions, four estimates of land-use change (LUC) emissions, ocean uptake from two different reconstructions, and the terrestrial sink modelled by the TRENDY project to identify the most likely causes of the 1940s plateau. We find that they greatly overestimate atmospheric CO2 growth rate during the plateau period, as well as in the 1960s, in spite of giving a plausible explanation for most of the 20th century carbon budget, especially from 1970 onwards. The mismatch between reconstructions and observations during the CO2 plateau epoch of 1940-1950 ranges between 0.9 and 2.0 Pg C yr-1, depending on the LUC dataset considered. This mismatch may be explained by (i) decadal variability in the ocean carbon sink not accounted for in the reconstructions we used, (ii) a further terrestrial sink currently missing in the estimates by land-surface models, or (iii) LUC processes not included in the current datasets. Ocean carbon models from CMIP5 indicate that natural variability in the ocean carbon sink could explain an additional 0.5 Pg C yr-1 uptake, but it is unlikely to be higher. The impact of the 1940-1942 El Niño on the

  19. Phosphate Uptake from Phytate Due to Hyphae-Mediated Phytase Activity by Arbuscular Mycorrhizal Maize.

    Science.gov (United States)

    Wang, Xin-Xin; Hoffland, Ellis; Feng, Gu; Kuyper, Thomas W

    2017-01-01

    Phytate is the most abundant form of soil organic phosphorus (P). Increased P nutrition of arbuscular mycorrhizal plants derived from phytate has been repeatedly reported. Earlier studies assessed acid phosphatase rather than phytase as an indication of mycorrhizal fungi-mediated phytate use. We investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize. Two maize ( Zea mays L.) cultivars, non-inoculated or inoculated with the arbuscular mycorrhizal fungi Funneliformis mosseae or Claroideoglomus etunicatum , were grown for 45 days in two-compartment rhizoboxes, containing a root compartment and a hyphal compartment. The soil in the hyphal compartment was supplemented with 20, 100, and 200 mg P kg -1 soil as calcium phytate. We measured activity of phytase and acid phosphatase in the hyphal compartment, hyphal length density, P uptake, and plant biomass. Our results showed: (1) phytate addition increased phytase and acid phosphatase activity, and resulted in larger P uptake and plant biomass; (2) increases in P uptake and biomass were correlated with phytase activity but not with acid phosphatase activity; (3) lower phytate addition rate increased, but higher addition rate decreased hyphal length density. We conclude that P from phytate can be taken up by arbuscular mycorrhizal plants and that phytase plays a more important role in mineralizing phytate than acid phosphatase.

  20. CO2 flowrate calculator

    International Nuclear Information System (INIS)

    Carossi, Jean-Claude

    1969-02-01

    A CO 2 flowrate calculator has been designed for measuring and recording the gas flow in the loops of Pegase reactor. The analog calculator applies, at every moment, Bernoulli's formula to the values that characterize the carbon dioxide flow through a nozzle. The calculator electronics is described (it includes a sampling calculator and a two-variable function generator), with its amplifiers, triggers, interpolator, multiplier, etc. Calculator operation and setting are presented

  1. Porous Organic Polymers for CO2 Capture

    KAUST Repository

    Teng, Baiyang

    2013-01-01

    to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs

  2. Contemporary reliance on bicarbonate acquisition predicts increased growth of seagrass Amphibolis antarctica in a high-CO2 world.

    Science.gov (United States)

    Burnell, Owen W; Connell, Sean D; Irving, Andrew D; Watling, Jennifer R; Russell, Bayden D

    2014-01-01

    Rising atmospheric CO2 is increasing the availability of dissolved CO2 in the ocean relative to HCO3 (-). Currently, many marine primary producers use HCO3 (-) for photosynthesis, but this is energetically costly. Increasing passive CO2 uptake relative to HCO3 (-) pathways could provide energy savings, leading to increased productivity and growth of marine plants. Inorganic carbon-uptake mechanisms in the seagrass Amphibolis antarctica were determined using the carbonic anhydrase inhibitor acetazolamide (AZ) and the buffer tris(hydroxymethyl)aminomethane (TRIS). Amphibolis antarctica seedlings were also maintained in current and forecasted CO2 concentrations to measure their physiology and growth. Photosynthesis of A. antarctica was significantly reduced by AZ and TRIS, indicating utilization of HCO3 (-)-uptake mechanisms. When acclimated plants were switched between CO2 treatments, the photosynthetic rate was dependent on measurement conditions but not growth conditions, indicating a dynamic response to changes in dissolved CO2 concentration, rather than lasting effects of acclimation. At forecast CO2 concentrations, seedlings had a greater maximum electron transport rate (1.4-fold), photosynthesis (2.1-fold), below-ground biomass (1.7-fold) and increase in leaf number (2-fold) relative to plants in the current CO2 concentration. The greater increase in photosynthesis (measured as O2 production) compared with the electron transport rate at forecasted CO2 concentration suggests that photosynthetic efficiency increased, possibly due to a decrease in photorespiration. Thus, it appears that the photosynthesis and growth of seagrasses reliant on energetically costly HCO3 (-) acquisition, such as A. antarctica, might increase at forecasted CO2 concentrations. Greater growth might enhance the future prosperity and rehabilitation of these important habitat-forming plants, which have experienced declines of global significance.

  3. Modeling the transformation of atmospheric CO2 into microalgal biomass.

    Science.gov (United States)

    Hasan, Mohammed Fahad; Vogt, Frank

    2017-10-23

    Marine phytoplankton acts as a considerable sink of atmospheric CO 2 as it sequesters large quantities of this greenhouse gas for biomass production. To assess microalgae's counterbalancing of global warming, the quantities of CO 2 they fix need to be determined. For this task, it is mandatory to understand which environmental and physiological parameters govern this transformation from atmospheric CO 2 to microalgal biomass. However, experimental analyses are challenging as it has been found that the chemical environment has a major impact on the physiological properties of the microalgae cells (diameter typ. 5-20 μm). Moreover, the cells can only chemically interact with their immediate vicinity and thus compound sequestration needs to be studied on a microscopic spatial scale. Due to these reasons, computer simulations are a more promising approach than the experimental studies. Modeling software has been developed that describes the dissolution of atmospheric CO 2 into oceans followed by the formation of HCO 3 - which is then transported to individual microalgae cells. The second portion of this model describes the competition of different cell species for this HCO 3 - , a nutrient, as well as its uptake and utilization for cell production. Two microalgae species, i.e. Dunaliella salina and Nannochloropsis oculata, were cultured individually and in a competition situation under different atmospheric CO 2 conditions. It is shown that this novel model's predictions of biomass production are in very good agreement with the experimental flow cytometry results. After model validation, it has been applied to long-term prediction of phytoplankton generation. These investigations were motivated by the question whether or not cell production slows down as cultures grow. This is of relevance as a reduced cell production rate means that the increase in a culture's CO 2 -sinking capacity slows down as well. One implication resulting from this is that an increase in

  4. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng; Liu, Xin; Han, Yu

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high

  5. CO2 laser development

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    The research and development programs on high-energy, short-pulse CO 2 lasers were begun at LASL in 1969. Three large systems are now either operating or are being installed. The Single-Beam System (SBS), a four-stage prototype, was designed in 1971 and has been in operation since 1973 with an output energy of 250 J in a 1-ns pulse with an on-target intensity of 3.5 x 10 14 W/cm 2 . The Dual-Beam System (DBS), now in the final stages of electrical and optical checkout, will provide about ten times more power for two-beam target irradiation experiments. Four such dual-beam modules are being installed in the Laser-Fusion Laboratory to provide an Eight-Beam System (EBS) scheduled for operation at the 5- to 10-TW level in 1977. A fourth system, a 100- to 200-TW CO 2 laser, is being designed for the High-Energy Gas Laser Facility (HEGLF) program

  6. Increasing CO2 storage in oil recovery

    International Nuclear Information System (INIS)

    Jessen, K.; Kovscek, A.R.; Orr, F.M. Jr.

    2005-01-01

    Oil fields offer a significant potential for storing CO 2 and will most likely be the first large scale geological targets for sequestration as the infrastructure, experience and permitting procedures already exist. The problem of co-optimizing oil production and CO 2 storage differs significantly from current gas injection practice due to the cost-benefit imbalance resulting from buying CO 2 for enhanced oil recovery projects. Consequently, operators aim to minimize the amount of CO 2 required to sweep an oil reservoir. For sequestration purposes, where high availability of low cost CO 2 is assumed, the design parameters of enhanced oil recovery processes must be re-defined to optimize the amount of CO 2 left in the reservoir at the time of abandonment. To redefine properly the design parameters, thorough insight into the mechanisms controlling the pore scale displacement efficiency and the overall sweep efficiency is essential. We demonstrate by calculation examples the different mechanisms controlling the displacement behavior of CO 2 sequestration schemes, the interaction between flow and phase equilibrium and how proper design of the injection gas composition and well completion are required to co-optimize oil production and CO 2 storage. [Author

  7. Increasing CO2 storage in oil recovery

    International Nuclear Information System (INIS)

    Jessen, Kristian; Kovscek, Anthony R.; Orr, Franklin M.

    2005-01-01

    Oil fields offer a significant potential for storing CO 2 and will most likely be the first large scale geological targets for sequestration as the infrastructure, experience and permitting procedures already exist. The problem of co-optimizing oil production and CO 2 storage differs significantly from current gas injection practice due to the cost-benefit imbalance resulting from buying CO 2 for enhanced oil recovery projects. Consequently, operators aim to minimize the amount of CO 2 required to sweep an oil reservoir. For sequestration purposes, where high availability of low cost CO 2 is assumed, the design parameters of enhanced oil recovery processes must be re-defined to optimize the amount of CO 2 left in the reservoir at the time of abandonment. To redefine properly the design parameters, thorough insight into the mechanisms controlling the pore scale displacement efficiency and the overall sweep efficiency is essential. We demonstrate by calculation examples the different mechanisms controlling the displacement behavior of CO 2 sequestration schemes, the interaction between flow and phase equilibrium and how proper design of the injection gas composition and well completion are required to co-optimize oil production and CO 2 storage

  8. Leaching due to hygroscopic water uptake in cemented waste containing soluble salts

    DEFF Research Database (Denmark)

    Brodersen, K.

    1992-01-01

    conditions, condensation of water vapour will result in generation of a certain amount of liquid in the form of a strong salt solution. The volume of liquid may well exceed the storage capacity of the pore system in the cemented material and in the release of a limited amount of free contaminated solution......Considerable amounts of easily soluble salts such as sodium nitrate, sulphate, or carbonate are introduced into certain types of cemented waste. When such materials are stored in atmospheres with high relative humidity or disposed or by shallow land burial under unsaturated, but still humid....... A model of the quantitative aspects for the equilibrium situation is presented. Experiments with hygroscopic water uptake support the model and give indications about the rate of the process. The release mechanism is only thought to be important for radionuclides which are not fixed in a low...

  9. On the causes of trends in the seasonal amplitude of atmospheric CO2.

    Science.gov (United States)

    Piao, Shilong; Liu, Zhuo; Wang, Yilong; Ciais, Philippe; Yao, Yitong; Peng, Shushi; Chevallier, Frédéric; Friedlingstein, Pierre; Janssens, Ivan A; Peñuelas, Josep; Sitch, Stephen; Wang, Tao

    2018-02-01

    No consensus has yet been reached on the major factors driving the observed increase in the seasonal amplitude of atmospheric CO 2 in the northern latitudes. In this study, we used atmospheric CO 2 records from 26 northern hemisphere stations with a temporal coverage longer than 15 years, and an atmospheric transport model prescribed with net biome productivity (NBP) from an ensemble of nine terrestrial ecosystem models, to attribute change in the seasonal amplitude of atmospheric CO 2 . We found significant (p 50°N), consistent with previous observations that the amplitude increased faster at Barrow (Arctic) than at Mauna Loa (subtropics). The multi-model ensemble mean (MMEM) shows that the response of ecosystem carbon cycling to rising CO 2 concentration (eCO 2 ) and climate change are dominant drivers of the increase in AMP P -T and AMP T -P in the high latitudes. At the Barrow station, the observed increase of AMP P -T and AMP T -P over the last 33 years is explained by eCO 2 (39% and 42%) almost equally than by climate change (32% and 35%). The increased carbon losses during the months with a net carbon release in response to eCO 2 are associated with higher ecosystem respiration due to the increase in carbon storage caused by eCO 2 during carbon uptake period. Air-sea CO 2 fluxes (10% for AMP P -T and 11% for AMP T -P ) and the impacts of land-use change (marginally significant 3% for AMP P -T and 4% for AMP T -P ) also contributed to the CO 2 measured at Barrow, highlighting the role of these factors in regulating seasonal changes in the global carbon cycle. © 2017 John Wiley & Sons Ltd.

  10. How much CO2 is trapped in carbonate minerals of a natural CO2 occurrence?

    Science.gov (United States)

    Király, Csilla; Szabó, Zsuzsanna; Szamosfalvi, Ágnes; Cseresznyés, Dóra; Király, Edit; Szabó, Csaba; Falus, György

    2017-04-01

    Carbon Capture and Storage (CCS) is a transitional technology to decrease CO2 emissions from human fossil fuel usage and, therefore, to mitigate climate change. The most important criteria of a CO2 geological storage reservoir is that it must hold the injected CO2 for geological time scales without its significant seepage. The injected CO2 undergoes physical and chemical reactions in the reservoir rocks such as structural-stratigraphic, residual, dissolution or mineral trapping mechanisms. Among these, the safest is the mineral trapping, when carbonate minerals such as calcite, ankerite, siderite, dolomite and dawsonite build the CO2 into their crystal structures. The study of natural CO2 occurrences may help to understand the processes in CO2 reservoirs on geological time scales. This is the reason why the selected, the Mihályi-Répcelak natural CO2 occurrence as our research area, which is able to provide particular and highly significant information for the future of CO2 storage. The area is one of the best known CO2 fields in Central Europe. The main aim of this study is to estimate the amount of CO2 trapped in the mineral phase at Mihályi-Répcelak CO2 reservoirs. For gaining the suitable data, we apply petrographic, major and trace element (microprobe and LA-ICP-MS) and stable isotope analysis (mass spectrometry) and thermodynamic and kinetic geochemical models coded in PHREEQC. Rock and pore water compositions of the same formation, representing the pre-CO2 flooding stages of the Mihályi-Répcelak natural CO2 reservoirs are used in the models. Kinetic rate parameters are derived from the USGS report of Palandri and Kharaka (2004). The results of petrographic analysis show that a significant amount of dawsonite (NaAlCO3(OH)2, max. 16 m/m%) precipitated in the rock due to its reactions with CO2 which flooded the reservoir. This carbonate mineral alone traps about 10-30 kg/m3 of the reservoir rock from the CO2 at Mihályi-Répcelak area, which is an

  11. CO2-Water-Rock Wettability: Variability, Influencing Factors, and Implications for CO2 Geostorage.

    Science.gov (United States)

    Iglauer, Stefan

    2017-05-16

    Carbon geosequestration (CGS) has been identified as a key technology to reduce anthropogenic greenhouse gas emissions and thus significantly mitigate climate change. In CGS, CO 2 is captured from large point-source emitters (e.g., coal fired power stations), purified, and injected deep underground into geological formations for disposal. However, the CO 2 has a lower density than the resident formation brine and thus migrates upward due to buoyancy forces. To prevent the CO 2 from leaking back to the surface, four trapping mechanisms are used: (1) structural trapping (where a tight caprock acts as a seal barrier through which the CO 2 cannot percolate), (2) residual trapping (where the CO 2 plume is split into many micrometer-sized bubbles, which are immobilized by capillary forces in the pore network of the rock), (3) dissolution trapping (where CO 2 dissolves in the formation brine and sinks deep into the reservoir due to a slight increase in brine density), and (4) mineral trapping (where the CO 2 introduced into the subsurface chemically reacts with the formation brine or reservoir rock or both to form solid precipitates). The efficiency of these trapping mechanisms and the movement of CO 2 through the rock are strongly influenced by the CO 2 -brine-rock wettability (mainly due to the small capillary-like pores in the rock which form a complex network), and it is thus of key importance to rigorously understand CO 2 -wettability. In this context, a substantial number of experiments have been conducted from which several conclusions can be drawn: of prime importance is the rock surface chemistry, and hydrophilic surfaces are water-wet while hydrophobic surfaces are CO 2 -wet. Note that CO 2 -wet surfaces dramatically reduce CO 2 storage capacities. Furthermore, increasing pressure, salinity, or dissolved ion valency increases CO 2 -wettability, while the effect of temperature is not well understood. Indeed theoretical understanding of CO 2 -wettability and the

  12. Enhanced Selectivity and Uptake Capacity of CO2 and Toluene Adsorption in Co0.5 M0.33 MoS4 (M= Sb or Y) Chalcogels by Impregnated Metal Salts

    KAUST Repository

    Edhaim, Fatimah A.; Rothenberger, Alexander

    2017-01-01

    The synthesis of metal chalcogenide aerogels Co0.5M0.33MoS4 (M= Sb or Y) by the sol-gel method is reported. In this system, the building blocks [MoS4]2− chelated with Co2+ and (Sb3+) or (Y3+) salts in nonaqueous solvents forming amorphous networks

  13. A perfluorinated covalent triazine-based framework for highly selective and water-tolerant CO2 capture

    KAUST Repository

    Zhao, Yunfeng

    2013-01-01

    We designed and synthesized a perfluorinated covalent triazine-based framework (FCTF-1) for selective CO2 capture. The incorporation of fluorine (F) groups played multiple roles in improving the framework\\'s CO 2 adsorption and separation capabilities. Thermodynamically, the strongly polar C-F bonds promoted CO2 adsorption via electrostatic interactions, especially at low pressures. FCTF-1\\'s CO2 uptake was 1.76 mmol g-1 at 273 K and 0.1 bar through equilibrium adsorption, exceeding the CO2 adsorption capacity of any reported porous organic polymers to date. In addition, incorporating F groups produced a significant amount of ultra-micropores (<0.5 nm), which offered not only high gas adsorption potential but also kinetic selectivity for CO2-N 2 separation. In mixed-gas breakthrough experiments, FCTF-1 exhibited an exceptional CO2-N2 selectivity of 77 under kinetic flow conditions, much higher than the selectivity (31) predicted from single-gas equilibrium adsorption data. Moreover, FCTF-1 proved to be tolerant to water and its CO2 capture performance remained excellent when there was moisture in the gas mixture, due to the hydrophobic nature of the C-F bonds. In addition, the moderate adsorbate-adsorbent interaction allowed it to be fully regenerated by pressure swing adsorption processes. These attributes make FCTF-1 a promising sorbent for CO2 capture from flue gas. © 2013 The Royal Society of Chemistry.

  14. CO2 Laser Market

    Science.gov (United States)

    Simonsson, Samuel

    1989-03-01

    It gives me a great deal of pleasure to introduce our final speaker of this morning's session for two reasons: First of all, his company has been very much in the news not only in our own community but in the pages of Wall Street Journal and in the world economic press. And, secondly, we would like to welcome him to our shores. He is a temporary resident of the United States, for a few months, forsaking his home in Germany to come here and help with the start up of a new company which we believe, probably, ranks #1 as the world supplier of CO2 lasers now, through the combination of former Spectra Physics Industrial Laser Division and Rofin-Sinar GMBH. Samuel Simonsson is the Chairman of the Board of Rofin-Sinar, Inc., here in the U.S. and managing director of Rofin-Sinar GMBH. It is a pleasure to welcome him.

  15. Atmospheric inversion of the surface CO2 flux with 13CO2 constraint

    Science.gov (United States)

    Chen, J. M.; Mo, G.; Deng, F.

    2013-10-01

    Observations of 13CO2 at 73 sites compiled in the GLOBALVIEW database are used for an additional constraint in a global atmospheric inversion of the surface CO2 flux using CO2 observations at 210 sites for the 2002-2004 period for 39 land regions and 11 ocean regions. This constraint is implemented using the 13CO2/CO2 flux ratio modeled with a terrestrial ecosystem model and an ocean model. These models simulate 13CO2 discrimination rates of terrestrial photosynthesis and respiration and ocean-atmosphere diffusion processes. In both models, the 13CO2 disequilibrium between fluxes to and from the atmosphere is considered due to the historical change in atmospheric 13CO2 concentration. For the 2002-2004 period, the 13CO2 constraint on the inversion increases the total land carbon sink from 3.40 to 3.70 Pg C yr-1 and decreases the total oceanic carbon sink from 1.48 to 1.12 Pg C yr-1. The largest changes occur in tropical areas: a considerable decrease in the carbon source in the Amazon forest, and this decrease is mostly compensated by increases in the ocean region immediately west of the Amazon and the southeast Asian land region. Our further investigation through different treatments of the 13CO2/CO2 flux ratio used in the inversion suggests that variable spatial distributions of the 13CO2 isotopic discrimination rate simulated by the models over land and ocean have considerable impacts on the spatial distribution of the inverted CO2 flux over land and the inversion results are not sensitive to errors in the estimated disequilibria over land and ocean.

  16. Spatial and temporal variability of seawater pCO2 within the Canadian Arctic Archipelago and Baffin Bay during the summer and autumn 2011

    Science.gov (United States)

    Geilfus, N.-X.; Pind, M. L.; Else, B. G. T.; Galley, R. J.; Miller, L. A.; Thomas, H.; Gosselin, M.; Rysgaard, S.; Wang, F.; Papakyriakou, T. N.

    2018-03-01

    The partial pressure of CO2 in surface water (pCO2sw) measured within the Canadian Arctic Archipelago (CAA) and Baffin Bay was highly variable with values ranging from strongly undersaturated (118 μatm) to slightly supersaturated (419 μatm) with respect to the atmospheric levels ( 386 μatm) during summer and autumn 2011. During summer, melting sea ice contributed to cold and fresh surface water and enhanced the ice-edge bloom, resulting in strong pCO2sw undersaturation. Coronation Gulf was the only area with supersaturated pCO2sw, likely due to warm CO2-enriched freshwater input from the Coppermine River. During autumn, the entire CAA (including Coronation Gulf) was undersaturated, despite generally increasing pCO2sw. Coronation Gulf was the one place where pCO2sw decreased, likely due to seasonal reduction in discharge from the Coppermine River and the decreasing sea surface temperature. The seasonal summer-to-autumn increase in pCO2sw across the archipelago is attributed in part to the continuous uptake of atmospheric CO2 through both summer and autumn and to the seasonal deepening of the surface mixed layer, bringing CO2-rich waters to the surface. These observations demonstrate how freshwater from sea ice melt and rivers affect pCO2sw differently. The general pCO2sw undersaturation during summer-autumn 2011 throughout the CAA and Baffin Bay give an estimated net oceanic sink for atmospheric CO2 over the study period of 11.4 mmol CO2 m-2 d-1, assuming no sea-air CO2 flux exchange across the sea-ice covered areas.

  17. Interannual variability in CO2 and CH4 exchange in a brackish tidal marsh in Northern California

    Science.gov (United States)

    Knox, S. H.; Windham-Myers, L.; Anderson, F. E.; Bergamaschi, B. A.

    2017-12-01

    Carbon (C) cycling in coastal wetlands is difficult to measure and model due to extremely dynamic atmospheric and hydrologic fluxes, as well as sensitivities to dynamic land- and ocean-based drivers. To date, few studies have begun continuous measurements of net ecosystem CO2 exchange (NEE) in these systems, and as such our understanding of the key drivers of NEE in coastal wetlands remain poorly understood. Recent eddy covariance measurements of NEE in these environments show considerable variability both within and across sites, with daily CO2 uptake and annual net CO2 budgets varying by nearly an order of magnitude between years and across locations. Furthermore, measurements of CH4 fluxes in these systems are even more limited, despite the potential for CH4 emissions from brackish and freshwater coastal wetlands. Here we present 3 years of near-continuous eddy covariance measurements of CO2 and CH4 fluxes from a brackish tidal marsh in Northern California and explore the drivers of interannual variability in CO2 and CH4 exchange. CO2 fluxes showed significant interannual variability; net CO2 uptake was near-zero in 2014 (6 ± 26 g C-CO2 m-2 yr-1), while much greater uptake was observed in 2015 and 2016 (209 ± 27 g C- CO2 m-2 yr-1 and 243 ± 26 g C-CO2 m-2 yr-1, respectively). Conversely, annual CH4 emissions were small and consistent across years, with the wetland emitting on average 1 ± 0.1 g C-CH4 m-2 yr-1. With respect to the net atmospheric GHG budget (assuming a sustained global warming potential (SGWP) of 45, expressed in units of CO2 equivalents), the wetland was near neutral in 2014, but a net GHG sink of 706 ± 105 g CO2 eq m-2 yr-1 and 836 ± 83 g CO2 eq m-2 yr-1 in 2015 and 2016, respectively. The large interannual variability in CO2 exchange was driven by notable year-to-year differences in temperature and precipitation as California experienced a severe drought and record high temperatures from 2012 to 2015. The large interannual variability in

  18. Intelligence in Ecology: How Internet of Things Expands Insights into the Missing CO2 Sink

    Directory of Open Access Journals (Sweden)

    Wenfeng Wang

    2016-01-01

    Full Text Available Arid region characterizes more than 30% of the Earth’s total land surface area and the area is still increasing due to the trends of desertification, yet the extent to which it modulates the global C balance has been inadequately studied. As an emerging technology, IoT monitoring can combine researchers, instruments, and field sites and generate archival data for a better understanding of soil abiotic CO2 uptake in arid region. Images’ similarity analyses based on IoT monitoring can help ecologists to find sites where the abiotic uptake can temporally dominate and how the negative soil respiration fluxes were produced, while IoT monitoring with a set of intelligent video recognition algorithms enables ecologists to revisit these sites and the experiments details through the videos. Therefore, IoT monitoring of geospatial images, videos, and associated optimization and control algorithms should be a research priority towards expanding insights for soil abiotic CO2 uptake and a better understanding of how the uptake happens in arid region. Nevertheless, there are still considerable uncertainties and difficulties in determining the overall perspective of IoT monitoring for insights into the missing CO2 sink.

  19. Global CO2 fluxes estimated from GOSAT retrievals of total column CO2

    Directory of Open Access Journals (Sweden)

    S. Basu

    2013-09-01

    Full Text Available We present one of the first estimates of the global distribution of CO2 surface fluxes using total column CO2 measurements retrieved by the SRON-KIT RemoTeC algorithm from the Greenhouse gases Observing SATellite (GOSAT. We derive optimized fluxes from June 2009 to December 2010. We estimate fluxes from surface CO2 measurements to use as baselines for comparing GOSAT data-derived fluxes. Assimilating only GOSAT data, we can reproduce the observed CO2 time series at surface and TCCON sites in the tropics and the northern extra-tropics. In contrast, in the southern extra-tropics GOSAT XCO2 leads to enhanced seasonal cycle amplitudes compared to independent measurements, and we identify it as the result of a land–sea bias in our GOSAT XCO2 retrievals. A bias correction in the form of a global offset between GOSAT land and sea pixels in a joint inversion of satellite and surface measurements of CO2 yields plausible global flux estimates which are more tightly constrained than in an inversion using surface CO2 data alone. We show that assimilating the bias-corrected GOSAT data on top of surface CO2 data (a reduces the estimated global land sink of CO2, and (b shifts the terrestrial net uptake of carbon from the tropics to the extra-tropics. It is concluded that while GOSAT total column CO2 provide useful constraints for source–sink inversions, small spatiotemporal biases – beyond what can be detected using current validation techniques – have serious consequences for optimized fluxes, even aggregated over continental scales.

  20. Emerging terawatt picosecond CO2 laser technology

    International Nuclear Information System (INIS)

    Pogorelsky, I.V.

    1997-09-01

    The first terawatt picosecond (TWps) CO 2 laser is under construction at the BNL Accelerator Test Facility (ATF). TWps-CO 2 lasers, having an order of magnitude longer wavelength than the well-known table-top terawatt solid state lasers, offer new opportunities for strong-field physics research. For laser wakefield accelerators (LWFA) the advantage of the new class of lasers is due to a gain of two orders of magnitude in the ponderomotive potential. The large average power of CO 2 lasers is important for the generation of hard radiation through Compton back-scattering of the laser off energetic electron beams. The authors discuss applications of TWps-CO 2 lasers for LWFA modules of a tentative electron-positron collider, for γ-γ (or γ-lepton) colliders, for a possible table-top source of high-intensity x-rays and gamma rays, and the generation of polarized positron beams

  1. Sequestering CO2 in the Ocean: Options and Consequences

    Science.gov (United States)

    Rau, G. H.; Caldeira, K.

    2002-12-01

    The likelihood of negative climate and environmental impacts associated with increasing atmospheric CO2 has prompted serious consideration of various CO2 mitigation strategies. Among these are methods of capturing and storing of CO2 in the ocean. Two approaches that have received the most attention in this regard have been i) ocean fertilization to enhanced biological uptake and fixation of CO2, and ii) the chemical/mechanical capture and injection of CO2 into the deep ocean. Both methods seek to enhance or speed up natural mechanisms of CO2 uptake and storage by the ocean, namely i) the biological CO2 "pump" or ii) the passive diffusion of CO2 into the surface ocean and subsequent mixing into the deep sea. However, as will be reviewed, concerns about the capacity and effectiveness of either strategy in long-term CO2 sequestration have been raised. Both methods are not without potentially significant environmental impacts, and the costs of CO2 capture and injection (option ii) are currently prohibitive. An alternate method of ocean CO2 sequestration would be to react and hydrate CO2 rich waste gases (e.g., power plant flue gas) with seawater and to subsequently neutralize the resulting carbonic acid with limestone to produce calcium and bicarbonate ions in solution. This approach would simply speed up the CO2 uptake and sequestration that naturally (but very slowly) occurs via global carbonate weathering. This would avoid much of the increased acidity associated with direct CO2 injection while obviating the need for costly CO2 separation and capture. The addition of the resulting bicarbonate- and carbonate-rich solution to the ocean would help to counter the decrease in pH and carbonate ion concentration, and hence loss of biological calcification that is presently occurring as anthropogenic CO2 invades the ocean from the atmosphere. However, as with any approach to CO2 mitigation, the costs, impacts, risks, and benefits of this method need to be better understood

  2. Forecasting global atmospheric CO2

    International Nuclear Information System (INIS)

    Agusti-Panareda, A.; Massart, S.; Boussetta, S.; Balsamo, G.; Beljaars, A.; Engelen, R.; Jones, L.; Peuch, V.H.; Chevallier, F.; Ciais, P.; Paris, J.D.; Sherlock, V.

    2014-01-01

    A new global atmospheric carbon dioxide (CO 2 ) real-time forecast is now available as part of the preoperational Monitoring of Atmospheric Composition and Climate - Interim Implementation (MACC-II) service using the infrastructure of the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System (IFS). One of the strengths of the CO 2 forecasting system is that the land surface, including vegetation CO 2 fluxes, is modelled online within the IFS. Other CO 2 fluxes are prescribed from inventories and from off-line statistical and physical models. The CO 2 forecast also benefits from the transport modelling from a state-of-the-art numerical weather prediction (NWP) system initialized daily with a wealth of meteorological observations. This paper describes the capability of the forecast in modelling the variability of CO 2 on different temporal and spatial scales compared to observations. The modulation of the amplitude of the CO 2 diurnal cycle by near-surface winds and boundary layer height is generally well represented in the forecast. The CO 2 forecast also has high skill in simulating day-to-day synoptic variability. In the atmospheric boundary layer, this skill is significantly enhanced by modelling the day-to-day variability of the CO 2 fluxes from vegetation compared to using equivalent monthly mean fluxes with a diurnal cycle. However, biases in the modelled CO 2 fluxes also lead to accumulating errors in the CO 2 forecast. These biases vary with season with an underestimation of the amplitude of the seasonal cycle both for the CO 2 fluxes compared to total optimized fluxes and the atmospheric CO 2 compared to observations. The largest biases in the atmospheric CO 2 forecast are found in spring, corresponding to the onset of the growing season in the Northern Hemisphere. In the future, the forecast will be re-initialized regularly with atmospheric CO 2 analyses based on the assimilation of CO 2 products retrieved from satellite

  3. Simulated effect of calcification feedback on atmospheric CO2 and ocean acidification

    Science.gov (United States)

    Zhang, Han; Cao, Long

    2016-01-01

    Ocean uptake of anthropogenic CO2 reduces pH and saturation state of calcium carbonate materials of seawater, which could reduce the calcification rate of some marine organisms, triggering a negative feedback on the growth of atmospheric CO2. We quantify the effect of this CO2-calcification feedback by conducting a series of Earth system model simulations that incorporate different parameterization schemes describing the dependence of calcification rate on saturation state of CaCO3. In a scenario with SRES A2 CO2 emission until 2100 and zero emission afterwards, by year 3500, in the simulation without CO2-calcification feedback, model projects an accumulated ocean CO2 uptake of 1462 PgC, atmospheric CO2 of 612 ppm, and surface pH of 7.9. Inclusion of CO2-calcification feedback increases ocean CO2 uptake by 9 to 285 PgC, reduces atmospheric CO2 by 4 to 70 ppm, and mitigates the reduction in surface pH by 0.003 to 0.06, depending on the form of parameterization scheme used. It is also found that the effect of CO2-calcification feedback on ocean carbon uptake is comparable and could be much larger than the effect from CO2-induced warming. Our results highlight the potentially important role CO2-calcification feedback plays in ocean carbon cycle and projections of future atmospheric CO2 concentrations. PMID:26838480

  4. Accelerating Net Terrestrial Carbon Uptake During the Warming Hiatus Due to Reduced Respiration

    Science.gov (United States)

    Ballantyne, Ashley; Smith, William; Anderegg, William; Kauppi, Pekka; Sarmiento, Jorge; Tans, Pieter; Shevliakova, Elena; Pan, Yude; Poulter, Benjamin; Anav, Alessandro; hide

    2017-01-01

    The recent warming hiatus presents an excellent opportunity to investigate climate sensitivity of carbon cycle processes. Here we combine satellite and atmospheric observations to show that the rate of net biome productivity (NBP) has significantly accelerated from - 0.007 +/- 0.065 PgC yr(exp -2) over the warming period (1982 to 1998) to 0.119 +/- 0.071 PgC yr(exp -2) over the warming hiatus (19982012). This acceleration in NBP is not due to increased primary productivity, but rather reduced respiration that is correlated (r = 0.58; P = 0.0007) and sensitive ( y = 4.05 to 9.40 PgC yr(exp -1) per C) to land temperatures. Global land models do not fully capture this apparent reduced respiration over the warming hiatus; however, an empirical model including soil temperature and moisture observations better captures the reduced respiration.

  5. Methane production from coal seams and CO2 uptake capability of the Mecsek mountain range, Hungary; Die Methangewinnung aus Kohlefloezen und das CO{sub 2}-Aufnahmevermoegen des Mecsek-Gebirges in Ungarn

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Z.N. [Univ. Miskolc (Hungary); Lakatos, I. [Forschungsinstitut der angewandten Chemie (Hungary); Foeldessy, J.; Toth, J.; Fodor, B.; Csecsei, T. [Ungarischer Geologischer Dienst, Rotaqua KFT (Hungary)

    2006-06-15

    Methane from the Mecsek mountain range coal seams is of vast economic importance. Modified geological models focusing on zones of enhanced permeability may be useful in the development of practicable winning technologies. High gas volumes are assumed in stowed material, which may be recovered by a simple technology. There is a power station in the vicinity which produces waste gases that may be used for injection, so the Mecsek region offers promising conditions for CO2 CBM production. The same power plant is also a potential consumer of the recovered methane. (orig.)

  6. Thermodynamic and kinetic studies on CO2 capture with Poly[VBTMA][Arg

    Science.gov (United States)

    Raja Shahrom, Maisara Shahrom; Wilfred, Cecilia Devi; Chong, Fai Kait

    2018-05-01

    This paper discusses the technologies for capturing CO2 from the natural gas using poly[VBTMA][Arg], a type of poly(ionic liquids) with an amino acid as the anion. The results revealed that the CO2 uptake increased from 3.23 mmol/g to 7.91 mmol/g at 1-10 bar, 298 K due to both chemical absorption and physical adsorption increments. Four adsorption isotherm models were applied to study the interaction between adsorbate and adsorbent to study the physical adsorption i.e. Freundlich, Langmuir, Dubinin Raduschkevich and Temkin isotherms at 298 K, 313 K and 333 K. Promising results were obtained that suggested the Freundlich model and the pseudo-first order model are well fitted with the kinetic data at 298 K with a 0.9943 R2 value. This study has provided empirical evidence to the current body of knowledge pertaining to CO2 capture technologies.

  7. Robust C–C bonded porous networks with chemically designed functionalities for improved CO2 capture from flue gas

    Directory of Open Access Journals (Sweden)

    Damien Thirion

    2016-10-01

    Full Text Available Effective carbon dioxide (CO2 capture requires solid, porous sorbents with chemically and thermally stable frameworks. Herein, we report two new carbon–carbon bonded porous networks that were synthesized through metal-free Knoevenagel nitrile–aldol condensation, namely the covalent organic polymer, COP-156 and 157. COP-156, due to high specific surface area (650 m2/g and easily interchangeable nitrile groups, was modified post-synthetically into free amine- or amidoxime-containing networks. The modified COP-156-amine showed fast and increased CO2 uptake under simulated moist flue gas conditions compared to the starting network and usual industrial CO2 solvents, reaching up to 7.8 wt % uptake at 40 °C.

  8. Photochemical efficiency of photosystem II, photon yield of O2 evolution, photosynthetic capacity, and carotenoid composition during the midday depression of net CO2 uptake in Arbutus unedo growing in Portugal.

    Science.gov (United States)

    Demmig-Adams, B; Adams, W W; Winter, K; Meyer, A; Schreiber, U; Pereira, J S; Krüger, A; Czygan, F C; Lange, O L

    1989-03-01

    During the "midday depression" of net CO2 exchange in the mediterranean sclerophyllous shrub Arbutus unedo, examined in the field in Portugal during August of 1987, several parameters indicative of photosynthetic competence were strongly and reversibly affected. These were the photochemical efficiency of photosystem (PS) II, measured as the ratio of variable to maximum chlorophyll fluorescence, as well as the photon yield and the capacity of photosynthetic O2 evolution at 10% CO2, of which the apparent photon yield of O2 evolution was most depressed. Furthermore, there was a strong and reversible increase in the content of the carotenoid zeaxanthin in the leaves that occurred at the expense of both violaxanthin and β-carotene. Diurnal changes in fluorescence characteristics were interpreted to indicate three concurrent effects on the photochemical system. First, an increase in the rate of radiationless energy dissipation in the antenna chlorophyll, reflected by changes in 77K fluorescence of PSII and PSI as well as in chlorophyll a fluorescence at ambient temperature. Second, a state shift characterized by an increase in the proportion of energy distributed to PSI as reflected by changes in PSI fluorescence. Third, an effect lowering the photon yield of O2 evolution and PSII fluorescence at ambient temperature without affecting PSII fluorescence at 77K which would be expected from a decrease in the activity of the water splitting enzyme system, i.e. a donor side limitation.

  9. Recent developments in CO2 lasers

    Science.gov (United States)

    Du, Keming

    1993-05-01

    CO2 lasers have been used in industry mainly for such things as cutting, welding, and surface processing. To conduct a broad spectrum of high-speed and high-quality applications, most of the developments in industrial CO2 lasers at the ILT are aimed at increasing the output power, optimizing the beam quality, and reducing the production costs. Most of the commercial CO2 lasers above 5 kW are transverse-flow systems using dc excitation. The applications of these lasers are limited due to the lower beam quality, the poor point stability, and the lower modulation frequency. To overcome the problems we developed a fast axial- flow CO2 laser using rf excitation with an output of 13 kW. In section 2 some of the results are discussed concerning the gas flow, the discharge, the resonator design, optical effects of active medium, the aerodynamic window, and the modulation of the output power. The first CO2 lasers ever built are diffusion-cooled systems with conventional dc excited cylindrical discharge tubes surrounded by cooling jackets. The output power per unit length is limited to 50 W/m by those lasers with cylindrical tubes. In the past few years considerable increases in the output power were achieved, using new mechanical geometries, excitation- techniques, and resonator designs. This progress in diffusion-cooled CO2 lasers is presented in section 3.

  10. CO2 as a refrigerant

    CERN Document Server

    2014-01-01

    A first edition, the IIR guide “CO2 as a Refrigerant” highlights the application of carbon dioxide in supermarkets, industrial freezers, refrigerated transport, and cold stores as well as ice rinks, chillers, air conditioning systems, data centers and heat pumps. This guide is for design and development engineers needing instruction and inspiration as well as non-technical experts seeking background information on a specific topic. Written by Dr A.B. Pearson, a well-known expert in the field who has considerable experience in the use of CO2 as a refrigerant. Main topics: Thermophysical properties of CO2 – Exposure to CO2, safety precautions – CO2 Plant Design – CO2 applications – Future prospects – Standards and regulations – Bibliography.

  11. CO2 removals and CO2 and non-CO2 trace gas emissions affected by human activity in the forests in the Republic of macedonia

    International Nuclear Information System (INIS)

    Grupche, Ljupcho; Lozanovski, Risto; Markovska, Natasha

    2001-01-01

    During 2000 and 2001 inventories of CO 2 removals and emissions caused by changes in forest and other woody biomass stocks, as well as the inventories of CO 2 and non-CO 2 trace gas emissions caused by forest conversions (accidental burning) were carried out. According to the forest area in ha, and depending on the differences between the annual biomass increment and annual biomass consumption, about 30-50% of total annual carbon uptake increment is released through the biomass consumption from stocks. 50-70% of the net annual carbon uptake converted to CO 2 identify the annual removals of this gas, which is on average 1805 Gg/yr, ranging between 1485 and 2243 Gg/yr. From 1990 to 1998 on average 4700 ha forest area (min. 110 ha in 1991, max. 14420 ha in 1993) was burned. Proportionally to the burned area, there was a release on average of 18.62 kt C annually (min. 0.42 kt C, max. 57.11 kt), related to 136.07 kt CO 2 on average (min. 1.5 kt CO 2 , max. 209.22 kt CO 2 ). (Original)

  12. Natural Analogues of CO2 Geological Storage

    International Nuclear Information System (INIS)

    Perez del Villar, L.; Pelayo, M.; Recreo, F.

    2007-01-01

    Geological storage of carbon dioxide is nowadays, internationally considered as the most effective method for greenhouse gas emission mitigation, in order to minimize the global climate change universally accepted. Nevertheless, the possible risks derived of this long-term storage have a direct influence on its public acceptance. Among the favourable geological formations to store CO2, depleted oil and gas fields, deep saline reservoirs, and unamiable coal seams are highlighted. One of the most important objectives of the R and D projects related to the CO2 geological storage is the evaluation of the CO2 leakage rate through the above mentioned geological formations. Therefore, it is absolutely necessary to increase our knowledge on the interaction among CO2, storage and sealing formations, as well as on the flow paths and the physical resistance of the sealing formation. The quantification of the CO2 leakage rate is essential to evaluate the effects on the human and animal health, as well as for the ecosystem and water quality. To achieve these objectives, the study of the natural analogues is very useful in order to know the natural leakage rate to the atmosphere, its flow paths, the physical, chemical and mineralogical modifications due to the long term interaction processes among the CO2 and the storage and sealing formations, as well as the effects on the groundwaters and ecosystems. In this report, we have tried to summarise the main characteristics of the natural reservoirs and surficial sources of CO2, which are both natural analogues of the geological storage and CO2 leakage, studied in EEUU, Europe and Australia. The main objective of this summary is to find the possible applications for long-term risk prediction and for the performance assessment by means of conceptual and numerical modelling, which will allow to validate the predictive models of the CO2 storage behaviour, to design and develop suitable monitoring techniques to control the CO2 behaviour

  13. Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported onto CO2 Capture Materials.

    Science.gov (United States)

    Yang, Hui-Juan; Yang, Hong; Hong, Yu-Hao; Zhang, Peng-Yang; Wang, Tao; Chen, Li-Na; Zhang, Feng-Yang; Wu, Qi-Hui; Tian, Na; Zhou, Zhi-You; Sun, Shi-Gang

    2018-03-09

    Cu is a unique catalyst for CO 2 electroreduction, since it can catalyze CO 2 reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO 2 is considered to facilitate the activity and selectivity of CO 2 reduction. Herein, a new strategy is presented for CO 2 reduction with improved C 2 H 4 selectivity on a Cu catalyst by using CO 2 capture materials as the support at ambient pressure. N-doped carbon (N x C) was synthesized through high-temperature carbonization of melamine and l-lysine. We observed that the CO 2 uptake capacity of N x C depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600-800 °C). The as-prepared CuO/N x C catalysts exhibit a considerably higher C 2 H 4 faradaic efficiency (36 %) than CuO supported on XC-72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C 2 H 4 faradaic efficiency and CO 2 uptake capacity of the supports for CuO. The local high CO 2 concentration near Cu catalysts, created by CO 2 capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C 2 H 4 . This study demonstrates that pairing Cu catalysts with CO 2 capture supports is a promising approach for designing highly effective CO 2 reduction electrocatalysts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Stopped-Flow Spectrophotometric Study of the Kinetics and Mechanism of CO2 Uptake by cis-[Cr(C2O4(BaraNH2(OH22]+ Cation and the Acid-Catalyzed Decomposition of cis-[Cr(C2O4(BaraNH2OCO2]− Anion in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Lech Chmurzyński

    2011-09-01

    Full Text Available The kinetics of CO2 uptake by the cis-[Cr(C2O4(BaraNH2(OH22]+ complex cation and the acid hydrolysis of the cis-[Cr(C2O4(BaraNH2OCO2]− complex anion (where BaraNH2 denotes methyl 3-amino-2,3-dideoxy-b-D-arabino-hexopyranoside were studied using the stopped-flow technique. The reactions under study were investigated in aqueous solution in the 288–308 K temperature range. In the case of the reaction between CO2 and cis-[Cr(C2O4(BaraNH2(OH22]+ cation variable pH values (6.82–8.91 and the constant ionic strength of solution (H+, Na+, ClO4− = 1.0 were used. Carbon dioxide was generated by the reaction between sodium pyruvate and hydrogen peroxide. The acid hydrolysis of cis-[Cr(C2O4(BaraNH2OCO2]− was investigated for varying concentrations of H+ ions (0.01–2.7 M. The obtained results enabled the determination of the number of steps of the studied reactions. Based on the kinetic equations, rate constants were determined for each step. Finally, mechanisms for both reactions were proposed and discussed. Based on the obtained results it was concluded that the carboxylation (CO2 uptake reactions of cis-[Cr(C2O4(BaraNH2(OH22]+ and the decarboxylation (acid hydrolysis of the cis-[Cr(C2O4(BaraNH2OCO2]− are the opposite of each other.

  15. The sequestration of CO2

    International Nuclear Information System (INIS)

    Le Thiez, P.

    2004-01-01

    The reduction of greenhouse gas emissions, especially CO 2 , represents a major technological and societal challenge in the fight against climate change. Among the measures likely to reduce anthropic CO 2 emissions, capture and geological storage holds out promise for the future. (author)

  16. CO2 Sequestration short course

    Energy Technology Data Exchange (ETDEWEB)

    DePaolo, Donald J. [Lawrence Berkeley National Laboratory; Cole, David R [The Ohio State University; Navrotsky, Alexandra [University of California-Davis; Bourg, Ian C [Lawrence Berkeley National Laboratory

    2014-12-08

    Given the public’s interest and concern over the impact of atmospheric greenhouse gases (GHGs) on global warming and related climate change patterns, the course is a timely discussion of the underlying geochemical and mineralogical processes associated with gas-water-mineral-interactions encountered during geological sequestration of CO2. The geochemical and mineralogical processes encountered in the subsurface during storage of CO2 will play an important role in facilitating the isolation of anthropogenic CO2 in the subsurface for thousands of years, thus moderating rapid increases in concentrations of atmospheric CO2 and mitigating global warming. Successful implementation of a variety of geological sequestration scenarios will be dependent on our ability to accurately predict, monitor and verify the behavior of CO2 in the subsurface. The course was proposed to and accepted by the Mineralogical Society of America (MSA) and The Geochemical Society (GS).

  17. Enzymes in CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

    The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

  18. Sulfonate-grafted porous polymer networks for preferential CO(2) adsorption at low pressure

    NARCIS (Netherlands)

    Lu, W.; Yuan, D.; Sculley, J.; Zhao, D.; Krishna, R.; Zhou, H.-C.

    2011-01-01

    A porous polymer network (PPN) grafted with sulfonic acid (PPN-6-SO3H) and its lithium salt (PPN-6-SO3Li) exhibit significant increases in isosteric heats of CO2 adsorption and CO2-uptake capacities. IAST calculations using single-component-isotherm data and a 15/85 CO2/N2 ratio at 295 K and 1 bar

  19. Evaluation of the influence of CO2 on hydrogen production by Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Willquist, K.; Claassen, P.A.M.; Niel, van E.W.J.

    2009-01-01

    Stripping gas is generally used to improve hydrogen yields in fermentations. Since CO2 is relatively easy to separate from hydrogen it could be an interesting stripping gas. However, a higher partial CO2 pressure is accompanied with an increased CO2 uptake in the liquid, where it hydrolyses and

  20. Implications of overestimated anthropogenic CO2 emissions on East Asian and global land CO2 flux inversion

    Science.gov (United States)

    Saeki, Tazu; Patra, Prabir K.

    2017-12-01

    Measurement and modelling of regional or country-level carbon dioxide (CO2) fluxes are becoming critical for verification of the greenhouse gases emission control. One of the commonly adopted approaches is inverse modelling, where CO2 fluxes (emission: positive flux, sink: negative flux) from the terrestrial ecosystems are estimated by combining atmospheric CO2 measurements with atmospheric transport models. The inverse models assume anthropogenic emissions are known, and thus the uncertainties in the emissions introduce systematic bias in estimation of the terrestrial (residual) fluxes by inverse modelling. Here we show that the CO2 sink increase, estimated by the inverse model, over East Asia (China, Japan, Korea and Mongolia), by about 0.26 PgC year-1 (1 Pg = 1012 g) during 2001-2010, is likely to be an artifact of the anthropogenic CO2 emissions increasing too quickly in China by 1.41 PgC year-1. Independent results from methane (CH4) inversion suggested about 41% lower rate of East Asian CH4 emission increase during 2002-2012. We apply a scaling factor of 0.59, based on CH4 inversion, to the rate of anthropogenic CO2 emission increase since the anthropogenic emissions of both CO2 and CH4 increase linearly in the emission inventory. We find no systematic increase in land CO2 uptake over East Asia during 1993-2010 or 2000-2009 when scaled anthropogenic CO2 emissions are used, and that there is a need of higher emission increase rate for 2010-2012 compared to those calculated by the inventory methods. High bias in anthropogenic CO2 emissions leads to stronger land sinks in global land-ocean flux partitioning in our inverse model. The corrected anthropogenic CO2 emissions also produce measurable reductions in the rate of global land CO2 sink increase post-2002, leading to a better agreement with the terrestrial biospheric model simulations that include CO2-fertilization and climate effects.

  1. Impact of climate change and variability on the global oceanic sink of CO2

    OpenAIRE

    Le Quéré, Corinne; Takahashi, Taro; Buitenhuis, Erik T.; Rödenbeck, Christian; Sutherland, Stewart C.

    2010-01-01

    About one quarter of the CO2 emitted to the atmosphere by human activities is absorbed annually by the ocean. All the processes that influence the oceanic uptake of CO2 are controlled by climate. Hence changes in climate (both natural and human-induced) are expected to alter the uptake of CO2 by the ocean. However, available information that constrains the direction, magnitude, or rapidity of the response of ocean CO2 to changes in climate is limited. We present an analysis of oceanic CO2 tre...

  2. Direct electroreduction of CO2 into hydrocarbon

    International Nuclear Information System (INIS)

    Winea, Gauthier; Ledoux, Marc-Jacques; Pham-Huu, Cuong; Gangeri, Miriam; Perathoner, Siglinda; Centi, Gabriele

    2006-01-01

    A lot of methods exist to directly reduce carbon dioxide into hydrocarbons: the photoelectrochemical process is certainly the most interesting, essentially due to the similarities with photosynthesis. As the human activities produce a great quantity of CO 2 , this one can then be considered as an infinite source of carbon. The products of this reaction are identical to those obtained during a Fischer-Tropsch reaction, that is to say hydrocarbons, alcohols and carboxylic acids. These works deal with the electrochemical reduction of CO 2 in standard conditions of temperature and pressure. The photochemical part has been replaced by a current generator as electrons source and a KHCO 3 aqueous solution as protons source. The first catalytic results clearly show that it is possible to reduce CO 2 into light hydrocarbons, typically from C1 to C9. (O.M.)

  3. CO2 pellet blasting studies

    International Nuclear Information System (INIS)

    Archibald, K.E.

    1997-01-01

    Initial tests with CO 2 pellet blasting as a decontamination technique were completed in 1993 at the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory (INEL). During 1996, a number of additional CO 2 pellet blasting studies with Alpheus Cleaning Technologies, Oak Ridge National Laboratory, and Pennsylvania State University were conducted. After the testing with Alpheus was complete, an SDI-5 shaved CO 2 blasting unit was purchased by the ICPP to test and determine its capabilities before using in ICPP decontamination efforts. Results of the 1996 testing will be presented in this report

  4. Dependency of climate change and carbon cycle on CO2 emission pathways

    International Nuclear Information System (INIS)

    Nohara, Daisuke; Yoshida, Yoshikatsu; Misumi, Kazuhiro; Ohba, Masamichi

    2013-01-01

    Previous research has indicated that the response of globally average temperature is approximately proportional to cumulative CO 2 emissions, yet evidence of the robustness of this relationship over a range of CO 2 emission pathways is lacking. To address this, we evaluate the dependency of climate and carbon cycle change on CO 2 emission pathways using a fully coupled climate–carbon cycle model. We design five idealized pathways (including an overshoot scenario for cumulative emissions), each of which levels off to final cumulative emissions of 2000 GtC. The cumulative emissions of the overshoot scenario reach 4000 GtC temporarily, subsequently reducing to 2000 GtC as a result of continuous negative emissions. Although we find that responses of climatic variables and the carbon cycle are largely independent of emission pathways, a much weakened Atlantic meridional overturning circulation (AMOC) is projected in the overshoot scenario despite cessation of emissions. This weakened AMOC is enhanced by rapid warming in the Arctic region due to considerable temporary elevation of atmospheric CO 2 concentration and induces the decline of surface air temperature and decrease of precipitation over the northern Atlantic and Europe region. Moreover, the weakened AMOC reduces CO 2 uptake by the Atlantic and Arctic oceans. However, the weakened AMOC contributes little to the global carbon cycle. In conclusion, although climate variations have been found to be dependent on emission pathways, the global carbon cycle is relatively independent of these emission pathways, at least superficially. (letter)

  5. Photosynthetic responses to elevated CO2 and O3 in Quercus ilex leaves at a natural CO2 spring

    International Nuclear Information System (INIS)

    Paoletti, E.; Seufert, G.; Della Rocca, G.; Thomsen, H.

    2007-01-01

    Photosynthetic stimulation and stomatal conductance (Gs) depression in Quercus ilex leaves at a CO 2 spring suggested no down-regulation. The insensitivity of Gs to a CO 2 increase (from ambient 1500 to 2000 μmol mol -1 ) suggested stomatal acclimation. Both responses are likely adaptations to the special environment of CO 2 springs. At the CO 2 -enriched site, not at the control site, photosynthesis decreased 9% in leaves exposed to 2x ambient O 3 concentrations in branch enclosures, compared to controls in charcoal-filtered air. The stomatal density reduction at high CO 2 was one-third lower than the concomitant Gs reduction, so that the O 3 uptake per single stoma was lower than at ambient CO 2 . No significant variation in monoterpene emission was measured. Higher trichome and mesophyll density were recorded at the CO 2 -enriched site, accounting for lower O 3 sensitivity. A long-term exposure to H 2 S, reflected by higher foliar S-content, and CO 2 might depress the antioxidant capacity of leaves close to the vent and increase their O 3 sensitivity. - Very high CO 2 concentrations did not compensate for the effects of O 3 on holm oak photosynthesis

  6. The Influence of CO2 Solubility in Brine on Simulation of CO2 Injection into Water Flooded Reservoir and CO2 WAG

    DEFF Research Database (Denmark)

    Yan, Wei; Stenby, Erling Halfdan

    2010-01-01

    Injection of CO2 into depleted oil reservoirs is not only a traditional way to enhance oil recovery but also a relatively cheaper way to sequester CO2 underground since the increased oil production can offset some sequestration cost. CO2 injection process is often applied to water flooded...... simulations were made for seven oil samples within a wide range of temperature, pressure and salinity. The results were analyzed in terms of the change in oil recovery due to different phase equilibrium descriptions, the delay in breakthrough and the CO2 lost to the aqueous phase. The influence of different...

  7. Geochemical Interaction of Middle Bakken Reservoir Rock and CO2 during CO2-Based Fracturing

    Science.gov (United States)

    Nicot, J. P.; Lu, J.; Mickler, P. J.; Ribeiro, L. H.; Darvari, R.

    2015-12-01

    This study was conducted to investigate the effects of geochemical interactions when CO2 is used to create the fractures necessary to produce hydrocarbons from low-permeability Middle Bakken sandstone. The primary objectives are to: (1) identify and understand the geochemical reactions related to CO2-based fracturing, and (2) assess potential changes of reservoir property. Three autoclave experiments were conducted at reservoir conditions exposing middle Bakken core fragments to supercritical CO2 (sc-CO2) only and to CO2-saturated synthetic brine. Ion-milled core samples were examined before and after the reaction experiments using scanning electron microscope, which enabled us to image the reaction surface in extreme details and unambiguously identify mineral dissolution and precipitation. The most significant changes in the reacted rock samples exposed to the CO2-saturated brine is dissolution of the carbonate minerals, particularly calcite which displays severely corrosion. Dolomite grains were corroded to a lesser degree. Quartz and feldspars remained intact and some pyrite framboids underwent slight dissolution. Additionally, small amount of calcite precipitation took place as indicated by numerous small calcite crystals formed at the reaction surface and in the pores. The aqueous solution composition changes confirm these petrographic observations with increase in Ca and Mg and associated minor elements and very slight increase in Fe and sulfate. When exposed to sc-CO2 only, changes observed include etching of calcite grain surface and precipitation of salt crystals (halite and anhydrite) due to evaporation of residual pore water into the sc-CO2 phase. Dolomite and feldspars remained intact and pyrite grains were slightly altered. Mercury intrusion capillary pressure tests on reacted and unreacted samples shows an increase in porosity when an aqueous phase is present but no overall porosity change caused by sc-CO2. It also suggests an increase in permeability

  8. CO2: a worldwide myth

    International Nuclear Information System (INIS)

    Gerondeau, Ch.

    2009-01-01

    In this book, the author demonstrates the paradox that reducing CO 2 emissions leads to no CO 2 abatement at all. This assertion is based on an obvious statement. Everybody knows that oil resources are going to be exhausted in few decades. The oil that industrialized countries will not use will be consumed by emerging countries and the CO 2 emissions will remain the same. Who would believe that the oil, gas or coal still available will remain unused? The Kyoto protocol, the national policies, the European agreements of emissions abatement, the carbon taxes, the emissions abatement requests sent to the rest of the world, all these actions cost a lot and are useless. CO 2 concentration in the atmosphere will inescapably double during the 21. century but, according to the author, without any catastrophic consequence for the Earth. (J.S.)

  9. Benthic Uptake Rate due to Hyporheic Exchange: The Effects of Streambed Morphology for Constant and Sinusoidally Varying Nutrient Loads

    Directory of Open Access Journals (Sweden)

    Daniele Tonina

    2015-01-01

    Full Text Available Hyporheic exchange carries reactive solutes, which may include biological oxygen demand (BOD, dissolved oxygen (DO and reactive dissolved inorganic nitrogen (Nr, into the sediment, where biochemical reactions consume DO. Here, we study the impact of streambed morphology, stream-reactive solute loads and their diel oscillations on the DO benthic uptake rate (BUR due to hyporheic processes. Our model solves the hyporheic flow field and the solute transport equations analytically, within a Lagrangian framework, considering advection, longitudinal diffusion and reactions modeled as first order kinetics. The application of the model to DO field measurements over a gravel bar-pool sequence shows a good match with measured DO concentrations with an overall agreement of 58% and a kappa index of 0.46. We apply the model to investigate the effects of daily constant and sinusoidally time varying stream BOD, DO and Nr loads and of the morphodynamic parameters on BUR. Our modeling results show that BUR varies as a function of bedform size and of nutrient loads and that the hyporheic zone may consume up to 0.06% of the stream DO at the pool-riffle bedform scale. Daily oscillations of stream BOD and DO loads have small effects on BUR, but may have an important influence on local hyporheic processes and organisms’ distribution.

  10. Connecting CO2. Feasibility study CO2 network Southwest Netherlands; Connecting CO2. Haalbaarheidsstudie CO2-netwerk Zuidwest-Nederland

    Energy Technology Data Exchange (ETDEWEB)

    Rutten, M.

    2009-06-10

    An overview is given of supply and demand of CO2 in the region Southwest Netherlands and the regions Antwerp and Gent in Belgium. Also attention is paid to possible connections between these regions [Dutch] Een inventarisatie wordt gegeven van vraag en aanbod van CO2 in de regio Zuidwest- Nederland en de regios Antwerpen en Gent in Belgie. Ook worden mogelijke koppelingen tussen de regios besproken.

  11. Performance Evaluation for China’s Planned CO2-IPDA

    Directory of Open Access Journals (Sweden)

    Ge Han

    2017-07-01

    Full Text Available Active remote sensing of atmospheric XCO2 has several advantages over existing passive remote sensors, including global coverage, a smaller footprint, improved penetration of aerosols, and night observation capabilities. China is planning to launch a multi-functional atmospheric observation satellite equipped with a CO2-IPDA (integrated path differential absorption Lidar to measure columnar concentrations of atmospheric CO2 globally. As space and power are limited on the satellite, compromises have been made to accommodate other passive sensors. In this study, we evaluated the sensitivity of the system’s retrieval accuracy and precision to some critical parameters to determine whether the current configuration is adequate to obtain the desired results and whether any further compromises are possible. We then mapped the distribution of random errors across China and surrounding regions using pseudo-observations to explore the performance of the planned CO2-IPDA over these regions. We found that random errors of less than 0.3% can be expected for most regions of our study area, which will allow the provision of valuable data that will help researchers gain a deeper insight into carbon cycle processes and accurately estimate carbon uptake and emissions. However, in the areas where major anthropogenic carbon sources are located, and in coastal seas, random errors as high as 0.5% are predicted. This is predominantly due to the high concentrations of aerosols, which cause serious attenuation of returned signals. Novel retrieving methods must, therefore, be developed in the future to suppress interference from low surface reflectance and high aerosol loading.

  12. Triazine containing N-rich microporous organic polymers for CO2 capture and unprecedented CO2/N2 selectivity

    International Nuclear Information System (INIS)

    Bhunia, Subhajit; Bhanja, Piyali; Das, Sabuj Kanti; Sen, Tapas; Bhaumik, Asim

    2017-01-01

    Targeted synthesis of microporous adsorbents for CO 2 capture and storage is very challenging in the context of remediation from green house gases. Herein we report two novel N-rich microporous networks SB-TRZ-CRZ and SB-TRZ-TPA by extensive incorporation of triazine containing tripodal moiety in the porous polymer framework. These materials showed excellent CO 2 storage capacities: SB-TRZ-CRZ displayed the CO 2 uptake capacity of 25.5 wt% upto 1 bar at 273 K and SB-TRZ-TPA gave that of 16 wt% under identical conditions. The substantial dipole quadruple interaction between network (polar triazine) and CO 2 boosts the selectivity for CO 2 /N 2 . SB-TRZ-CRZ has this CO 2 /N 2 selectivity ratio of 377, whereas for SB-TRZ-TPA it was 97. Compared to other porous polymers, these materials are very cost effective, scalable and very promising material for clean energy application and environmental issues. - Graphical abstract: We report two novel N-rich microporous polymeric materials by doping of triazine containing tripodal dopant in the organic framework. These materials showed excellent CO 2 storage capacities as high as 25.5 wt% under 1 bar pressure with exceptional CO 2 /N 2 selectivity of 377. - Highlights: • Triazine containing trimodal moiety incorporated in polycarbazolic and poly triphenylamine networks. • N-rich crosslinked polymers with high BET surface area and 1.5–1.7 nm size large micropores. • CO 2 uptake capacity of 25.5 wt% upto 1 bar at 273 K. • These crosslinked porous polymers showed exceptional CO 2 /N 2 selectivity.

  13. Molecular Dynamics Simulations for Loading-Dependent Diffusion of CO2, SO2, CH4, and Their Binary Mixtures in ZIF-10: The Role of Hydrogen Bond.

    Science.gov (United States)

    Li, Li; Yang, Deshuai; Fisher, Trevor R; Qiao, Qi; Yang, Zhen; Hu, Na; Chen, Xiangshu; Huang, Liangliang

    2017-10-24

    The loading-dependent diffusion behavior of CH 4 , CO 2 , SO 2 , and their binary mixtures in ZIF-10 has been investigated in detail by using classical molecular dynamics simulations. Our simulation results demonstrate that the self-diffusion coefficient D i of CH 4 molecules decreases sharply and monotonically with the loading while those of both CO 2 and SO 2 molecules initially display a slight increase at low uptakes and follow a slow decrease at high uptakes. Accordingly, the interaction energies between CH 4 molecules and ZIF-10 remain nearly constant regardless of the loading due to the absence of hydrogen bonds (HBs), while the interaction energies between CO 2 (or SO 2 ) and ZIF-10 decease rapidly with the loading, especially at small amounts of gas molecules. Such different loading-dependent diffusion and interaction mechanisms can be attributed to the relevant HB behavior between gas molecules and ZIF-10. At low loadings, both the number and strength of HBs between CO 2 (or SO 2 ) molecules and ZIF-10 decrease obviously as the loading increases, which is responsible for the slight increase of their diffusion coefficients. However, at high loadings, their HB strength increases with the loading. Similar loading-dependent phenomena of diffusion, interaction, and HB behavior can be observed for CH 4, CO 2 , and SO 2 binary mixtures in ZIF-10, only associated with some HB competition between CO 2 and SO 2 molecules in the case of the CO 2 /SO 2 mixture.

  14. Revised budget for the oceanic uptake of anthropogenic carbon dioxide

    Science.gov (United States)

    Sarmiento, J.L.; Sundquist, E.T.

    1992-01-01

    TRACER-CALIBRATED models of the total uptake of anthropogenic CO2 by the world's oceans give estimates of about 2 gigatonnes carbon per year1, significantly larger than a recent estimate2 of 0.3-0.8 Gt C yr-1 for the synoptic air-to-sea CO2 influx. Although both estimates require that the global CO2 budget must be balanced by a large unknown terrestrial sink, the latter estimate implies a much larger terrestrial sink, and challenges the ocean model calculations on which previous CO2 budgets were based. The discrepancy is due in part to the net flux of carbon to the ocean by rivers and rain, which must be added to the synoptic air-to-sea CO2 flux to obtain the total oceanic uptake of anthropogenic CO2. Here we estimate the magnitude of this correction and of several other recently proposed adjustments to the synoptic air-sea CO2 exchange. These combined adjustments minimize the apparent inconsistency, and restore estimates of the terrestrial sink to values implied by the modelled oceanic uptake.

  15. CO2 Capture and Reuse

    International Nuclear Information System (INIS)

    Thambimuthu, K.; Gupta, M.; Davison, J.

    2003-01-01

    CO2 capture and storage including its utilization or reuse presents an opportunity to achieve deep reductions in greenhouse gas emissions from fossil energy use. The development and deployment of this option could significantly assist in meeting a future goal of achieving stabilization of the presently rising atmospheric concentration of greenhouse gases. CO2 capture from process streams is an established concept that has achieved industrial practice. Examples of current applications include the use of primarily, solvent based capture technologies for the recovery of pure CO2 streams for chemical synthesis, for utilization as a food additive, for use as a miscible agent in enhanced oil recovery operations and removal of CO2 as an undesired contaminant from gaseous process streams for the production of fuel gases such as hydrogen and methane. In these applications, the technologies deployed for CO2 capture have focused on gas separation from high purity, high pressure streams and in reducing (or oxygen deficient) environments, where the energy penalties and cost for capture are moderately low. However, application of the same capture technologies for large scale abatement of greenhouse gas emissions from fossil fuel use poses significant challenges in achieving (at comparably low energy penalty and cost) gas separation in large volume, dilute concentration and/or low pressure flue gas streams. This paper will focus on a review of existing commercial methods of CO2 capture and the technology stretch, process integration and energy system pathways needed for their large scale deployment in fossil fueled processes. The assessment of potential capture technologies for the latter purpose will also be based on published literature data that are both 'transparent' and 'systematic' in their evaluation of the overall cost and energy penalties of CO2 capture. In view of the of the fact that many of the existing commercial processes for CO2 capture have seen applications in

  16. CO2 emissions in the World in 2013

    International Nuclear Information System (INIS)

    Ecoiffier, Mathieu

    2015-12-01

    This publication presents and comments data of CO 2 emissions in the world and their evolution. It more particularly addresses CO 2 emissions due to energy combustion which represent more than 80 per cent of these emissions or 62 per cent of greenhouse gas emissions, and which increased in 2013 with respect to 2012 (+ 2.2 pc). The distribution of CO 2 emissions due to energy combustion in different continents and regions is indicated (levels in 1990, 2012 and 2013, evolutions). The decrease of the CO 2 emission intensity with respect to the GDP is briefly commented (evolution since 1970), as well as the level of CO 2 emissions per inhabitant in China with respect to that in the EU (evolutions since 1970). The evolution of CO 2 emissions is then analysed with respect to different determining parameters according to the Kaya equation (population, GDP, primary energy consumption and their evolution or relationship one to each other)

  17. Effects of CO2 on particle size distribution and phytoplankton abundance during a mesocosm bloom experiment (PeECE II

    Directory of Open Access Journals (Sweden)

    M. Schartau

    2008-04-01

    Full Text Available The influence of seawater carbon dioxide (CO2 concentration on the size distribution of suspended particles (2–60 μm and on phytoplankton abundance was investigated during a mesocosm experiment at the large scale facility (LFS in Bergen, Norway, in the frame of the Pelagic Ecosystem CO2 Enrichment study (PeECE II. In nine outdoor enclosures the partial pressure of CO2 in seawater was modified by an aeration system to simulate past (~190 μatm CO2, present (~370 μatm CO2 and future (~700 μatm CO2 CO2 conditions in triplicates. Due to the initial addition of inorganic nutrients, phytoplankton blooms developed in all mesocosms and were monitored over a period of 19 days. Seawater samples were collected daily for analysing the abundance of suspended particles and phytoplankton with the Coulter Counter and with Flow Cytometry, respectively. During the bloom period, the abundance of small particles (2 levels. At that time, a direct relationship between the total-surface-to-total-volume ratio of suspended particles and DIC concentration was determined for all mesocosms. Significant changes with respect to the CO2 treatment were also observed in the phytoplankton community structure. While some populations such as diatoms seemed to be insensitive to the CO2 treatment, others like Micromonas spp. increased with CO2, or showed maximum abundance at present day CO2 (i.e. Emiliania huxleyi. The strongest response to CO2 was observed in the abundance of small autotrophic nano-plankton that strongly increased during the bloom in the past CO2 mesocosms. Together, changes in particle size distribution and phytoplankton community indicate a complex interplay between the ability of the cells to physiologically respond to changes in CO2 and size selection. Size of cells is of general importance for a variety of processes in marine systems such as diffusion-limited uptake of substrates, resource allocation, predator-prey interaction, and gravitational settling

  18. Temporal and spatial variations of oceanic pCO2 and air-sea CO2 flux in th Greenland Sea and the Barents Sea

    International Nuclear Information System (INIS)

    Nakaoka, Shin-Ichiro; Aoki, Shuji; Nakazawa, Takakiyo; Yoshikawa-Inoue, Hisayuki

    2006-01-01

    In order to elucidate the seasonal and inter annual variations of oceanic CO 2 uptake in the Greenland Sea and the Barents Sea, the partial pressure of CO 2 in the surface ocean (pCO 2 sea ) was measured in all seasons between 1992 and 2001. We derived monthly varying relationships between pCO 2 sea and sea surface temperature (SST) and combined them with the SST data from the NCEP/NCAR reanalysis to determine pCO 2 sea and air-sea CO 2 flux in these seas. The pCO 2 sea values were normalized to the year 1995 by assuming that pCO 2 sea increased at the same growth rate (1.5 μatm/yr) of the pCO 2 in the air (pCO 2 air ) between 1992 and 2001. In 1995, the annual net air-sea CO 2 fluxes were evaluated to be 52 ± 20 gC/m 2 /yr in the Greenland Sea and 46 ± 18 gC/m 2 /yr in the Barents Sea. The CO 2 flux into the ocean reached its maximum in winter and minimum in summer. The wind speed and (delta)pCO 2 (=pCO 2 air -pCO 2 sea ) exerted a greater influence on the seasonal variation than the sea ice coverage. The annual CO 2 uptake examined in this study (70-80 deg N, 20 deg W-40 deg E) was estimated to be 0.050 ± 0.020 GtC/yr in 1995. The inter annual variation in the annual CO 2 uptake was found to be positively correlated with the North Atlantic Oscillation Index (NAOI) via wind strength but negatively correlated with (delta)pCO 2 and the sea ice coverage. The present results indicate that the variability in wind speed and sea ice coverage play a major role, while that in (delta)pCO 2 plays a minor role, in determining the interannual variation of CO 2 uptake in this area

  19. Crassulacean Acid Metabolism in the Epiphyte Tillandsia usneoides L. (Spanish Moss) : RESPONSES OF CO(2) EXCHANGE TO CONTROLLED ENVIRONMENTAL CONDITIONS.

    Science.gov (United States)

    Martin, C E; Siedow, J N

    1981-08-01

    Patterns of CO(2) exchange in Spanish moss under various experimental conditions were measured using an infrared gas analysis system. Plants were collected from a study site in North Carolina and placed in a gas exchange chamber for several days of continuous measurements. No substantial seasonal effects on CO(2) exchange were observed. High rates of nocturnal CO(2) uptake were observed under day/night temperature regimes of 25/10, 25/15, 25/20, 30/20, and 35/20 C; however, daytime temperatures of 40 C eliminated nighttime CO(2) uptake and a nighttime temperature of 5 C eliminated nocturnal CO(2) uptake, regardless of day temperature. Constant chamber conditions also inhibited nocturnal CO(2) uptake. Constant high relative humidity (RH) slightly stimulated CO(2) uptake while low nighttime RH reduced nocturnal CO(2) uptake.Reductions in daytime irradiance to approximately 25% full sunlight had no effect on CO(2) exchange. Continuous darkness resulted in continuous CO(2) loss by the plants, but a CO(2) exchange pattern similar to normal day/night conditions was observed under constant illumination. High tissue water content inhibited CO(2) uptake. Wetting of the tissue at any time of day or night resulted in net CO(2) loss. Abrupt increases in temperature or decreases in RH resulted in sharp decreases in net CO(2) uptake.The results indicate that Spanish moss is tolerant of a wide range of temperatures, irradiances, and water contents. They also indicate that high nighttime RH is a prerequisite for high rates of CO(2) uptake.

  20. ROOT-GROWTH AND FUNCTIONING UNDER ATMOSPHERIC CO2 ENRICHMENT

    NARCIS (Netherlands)

    STULEN, [No Value; DENHERTOG, J

    This paper examines the extent to which atmospheric CO2 enrichment may influence growth of plant roots and function in terms of uptake of water and nutrients, and carbon allocation towards symbionts. It is concluded that changes in dry matter allocation greatly depend on the experimental conditions

  1. Natural Analogues of CO2 Geological Storage; Analogos Naturales del Almacenamiento Geologico de CO2

    Energy Technology Data Exchange (ETDEWEB)

    Perez del Villar, L; Pelayo, M; Recreo, F

    2007-07-20

    Geological storage of carbon dioxide is nowadays, internationally considered as the most effective method for greenhouse gas emission mitigation, in order to minimize the global climate change universally accepted. Nevertheless, the possible risks derived of this long-term storage have a direct influence on its public acceptance. Among the favourable geological formations to store CO2, depleted oil and gas fields, deep saline reservoirs, and unamiable coal seams are highlighted. One of the most important objectives of the R and D projects related to the CO2 geological storage is the evaluation of the CO2 leakage rate through the above mentioned geological formations. Therefore, it is absolutely necessary to increase our knowledge on the interaction among CO2, storage and sealing formations, as well as on the flow paths and the physical resistance of the sealing formation. The quantification of the CO2 leakage rate is essential to evaluate the effects on the human and animal health, as well as for the ecosystem and water quality. To achieve these objectives, the study of the natural analogues is very useful in order to know the natural leakage rate to the atmosphere, its flow paths, the physical, chemical and mineralogical modifications due to the long term interaction processes among the CO2 and the storage and sealing formations, as well as the effects on the groundwaters and ecosystems. In this report, we have tried to summarise the main characteristics of the natural reservoirs and surficial sources of CO2, which are both natural analogues of the geological storage and CO2 leakage, studied in EEUU, Europe and Australia. The main objective of this summary is to find the possible applications for long-term risk prediction and for the performance assessment by means of conceptual and numerical modelling, which will allow to validate the predictive models of the CO2 storage behaviour, to design and develop suitable monitoring techniques to control the CO2 behaviour

  2. A diatom record of CO2 decline since the late Miocene

    Science.gov (United States)

    Mejía, Luz María; Méndez-Vicente, Ana; Abrevaya, Lorena; Lawrence, Kira T.; Ladlow, Caroline; Bolton, Clara; Cacho, Isabel; Stoll, Heather

    2017-12-01

    Extratropical sea surface temperature records from alkenones record a dramatic cooling of up to 17 °C over the last ∼14 Ma, but the relationship between this cooling and greenhouse gas forcing has been elusive due to sparse and contrasting reconstructions of atmospheric CO2 for the time period. Alkenone carbon isotopic fractionation during photosynthesis has previously been used to estimate changes in pCO2 over this interval, but is complicated by significant changes in cell size of the alkenone-producing coccolithophorids over this time period. In this study, we reconstruct carbon isotopic fractionation during photosynthesis (εp) using organic compounds trapped within the frustules of pennate diatoms in sediments from the Eastern Equatorial Pacific Ocean at Ocean Drilling Program Site 846 over the last ∼13 Ma. Physical separation of pennate diatoms prior to measuring carbon isotopic fractionation enables us to obtain a record with constant cell geometry, eliminating this factor of uncertainty in our pCO2 reconstruction. In the past ∼11 Ma, εp declines from 15.5 to 10.3‰. Using the classic diffusive model and taking into account variations in opal content, alkenone concentration and coccolith Sr/Ca as indicators of past productivity and growth rate, and sea surface temperature records from the site, we estimate a decline in pCO2 from 454 (+ / - 41) to 250 (+ / - 15) ppmv between ∼11 and 6 Ma. Models accounting for changing the significance of active carbon uptake for photosynthesis, which likely produce more accurate CO2 estimates, suggest a significant larger pCO2 decline of up to twice that shown by the classic diffusive model (in average from 794 (+ / - 233) ppmv at ∼11 Ma to 288 (+/-25) ppmv at ∼6 Ma, considering growth rates varying between 0.5 and 1.7 day-1). Large uncertainties in the pCO2 estimated between ∼8 and 11 Ma using the active uptake model are related to the growth rate used for calculations. Together, these results suggest CO2

  3. The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks

    Directory of Open Access Journals (Sweden)

    N. R. Bates

    2009-11-01

    Full Text Available At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2 on the order of −66 to −199 Tg C year−1 (1012 g C, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3 mineral saturation states (Ω of seawater while seasonal phytoplankton primary production (PP mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems

  4. Use of sediment CO2 by submersed rooted plants

    DEFF Research Database (Denmark)

    Winkel, Anders; Borum, Jens

    2009-01-01

    freshwater plants with different morphology and growth characteristics (Lobelia dortmanna, Lilaeopsis macloviana, Ludwigia repens, Vallisneria americana and Hydrocotyle verticillata) are able to support photosynthesis supplied by uptake of CO2 from the sediment. Methods: Gross photosynthesis was measured......Background and Aims: Submersed plants have different strategies to overcome inorganic carbon limitation. It is generally assumed that only small rosette species (isoetids) are able to utilize the high sediment CO2 availability. The present study examined to what extent five species of submersed......, the shoot to root ratio on an areal basis was the single factor best explaining variability in the importance of sediment CO2. For Ludwigia, diffusion barriers limited uptake or transport from roots to stems and transport from stems to leaves. Conclusions: Submersed plants other than isoetids can utilize...

  5. The CO2nnect activities

    Science.gov (United States)

    Eugenia, Marcu

    2014-05-01

    Climate change is one of the biggest challenges we face today. A first step is the understanding the problem, more exactly what is the challenge and the differences people can make. Pupils need a wide competencies to meet the challenges of sustainable development - including climate change. The CO2nnect activities are designed to support learning which can provide pupils the abilities, skills, attitudes and awareness as well as knowledge and understanding of the issues. The project "Together for a clean and healthy world" is part of "The Global Educational Campaign CO2nnect- CO2 on the way to school" and it was held in our school in the period between February and October 2009. It contained a variety of curricular and extra-curricular activities, adapted to students aged from 11 to 15. These activities aimed to develop in students the necessary skills to understanding man's active role in improving the quality of the environment, putting an end to its degrading process and to reducing the effects of climate changes caused by the human intervention in nature, including transport- a source of CO2 pollution. The activity which I propose can be easily adapted to a wide range of age groups and linked to the curricula of many subjects: - Investigate CO2 emissions from travel to school -Share the findings using an international database -Compare and discuss CO2 emissions -Submit questions to a climate- and transport expert -Partner with other schools -Meet with people in your community to discuss emissions from transport Intended learning outcomes for pupils who participate in the CO2nnect campaign are: Understanding of the interconnected mobility- and climate change issue climate change, its causes and consequences greenhouse-gas emissions from transport and mobility the interlinking of social, environmental, cultural and economic aspects of the local transport system how individual choices and participation can contribute to creating a more sustainable development

  6. CO2 storage in Sweden

    International Nuclear Information System (INIS)

    Ekstroem, Clas; Andersson, Annika; Kling, Aasa; Bernstone, Christian; Carlsson, Anders; Liljemark, Stefan; Wall, Caroline; Erstedt, Thomas; Lindroth, Maria; Tengborg, Per; Edstroem, Mikael

    2004-07-01

    This study considers options, that could be feasible for Sweden, to transport and geologically store CO 2 , providing that technology for electricity production with CO 2 capture will be available in the future and also acceptable from cost- and reliability point of view. As a starting point, it is assumed that a new 600-1000 MW power plant, fired with coal or natural gas, will be constructed with CO 2 capture and localised to the Stockholm, Malmoe or Goeteborg areas. Of vital importance for storage of carbon dioxide in a reservoir is the possibility to monitor its distribution, i.e. its migration within the reservoir. It has been shown in the SACS-project that the distribution of carbon dioxide within the reservoir can be monitored successfully, mainly by seismic methods. Suitable geologic conditions and a large storage potential seems to exist mainly in South West Scania, where additional knowledge on geology/hydrogeology has been obtained since the year 2000 in connection to geothermal energy projects, and in the Eastern part of Denmark, bordering on South West Scania. Storage of carbon dioxide from the Stockholm area should not be excluded, but more studies are needed to clarify the storage options within this area. The possibilities to use CO 2 for enhanced oil recovery, EOR, in i.a. the North Sea should be investigated, in order to receive incomes from the CO 2 and shared costs for infrastructure, and by this also make the CO 2 regarded as a trading commodity, and thereby achieving a more favourable position concerning acceptance, legal issues and regulations. The dimensions of CO 2 -pipelines should be similar to those for natural natural gas, although regarding some aspects they have different design and construction prerequisites. To obtain cost efficiency, the transport distances should be kept short, and possibilities for co-ordinated networks with short distribution pipelines connected to common main pipelines, should be searched for. Also, synergies

  7. Specific radioactivity of glycolate and photorespiration during 14CO2 assimilation at four different CO2 concentrations by sunflower and bean leaves

    International Nuclear Information System (INIS)

    Fock, H.; Klug, K.; Krampitz, M.J.

    1979-01-01

    Using an open gas-exchange system, the rates of apparent CO 2 uptake (APS), true CO 2 uptake (TIPS), CO 2 evolution in light (PR), and the relative specific radioactivity of photorespiration (RSA) by sunflower and bean leaves were measured at four different CO 2 concentrations. At the end of the 14 CO 2 assimilation period the leaves were killed and extract for the analysis of glycolic acid. The rate of PR was CO 2 independent at low and normal CO 2 concentrations but inreased at CO 2 concentrations above normal. The ratio of PR/TPS which declined with an increase in CO 2 was compatible with the ratio of vo/2vo of the RuBP-Carboxylase/Oxygenase reaction. At low and normal concentrations of CO 2 the concentration as well as the specific radioactivity of glycolic acid increased with an increase in CO 2 and the relative specific activity (RSA) of glycolic acid resembled the RSA of photorespiration. It was concluded that these results support the concept of RuBP-carboxylase/oxygenase regulating the fluxes of carbon via the photosynthetic carbon reduction and the glycolate pathway. (orig.) [de

  8. CO2 impulse response curves for GWP calculations

    International Nuclear Information System (INIS)

    Jain, A.K.; Wuebbles, D.J.

    1993-01-01

    The primary purpose of Global Warming Potential (GWP) is to compare the effectiveness of emission strategies for various greenhouse gases to those for CO 2 , GWPs are quite sensitive to the amount of CO 2 . Unlike all other gases emitted in the atmosphere, CO 2 does not have a chemical or photochemical sink within the atmosphere. Removal of CO 2 is therefore dependent on exchanges with other carbon reservoirs, namely, ocean and terrestrial biosphere. The climatic-induced changes in ocean circulation or marine biological productivity could significantly alter the atmospheric CO 2 lifetime. Moreover, continuing forest destruction, nutrient limitations or temperature induced increases of respiration could also dramatically change the lifetime of CO 2 in the atmosphere. Determination of the current CO 2 sinks, and how these sinks are likely to change with increasing CO 2 emissions, is crucial to the calculations of GWPs. It is interesting to note that the impulse response function is sensitive to the initial state of the ocean-atmosphere system into which CO 2 is emitted. This is due to the fact that in our model the CO 2 flux from the atmosphere to the mixed layer is a nonlinear function of ocean surface total carbon

  9. The CO2 lifetime concept should be banished

    International Nuclear Information System (INIS)

    Tans, P.S.

    1997-01-01

    Presenting an alternative view to that of Brian O'Neill et al. (p. 491-503 of this journal issue), the author argues that as carbon goes continually back and forth between its different forms, gaseous CO 2 , dissolved CO 2 , bicarbonate and carbonate ions, it is difficult to assign a lifetime to the fraction of the emitted CO 2 staying airborne permanently. The non-linear nature of partial uptake of CO 2 by the oceans also adds to this difficulty. Titration reactions and chemical equilibrium introduce 'mystery' into measurements - carbon does not actually leave the atmosphere-biosphere-ocean system. This has implications for any greenhouse gas abatement policy. Assigning a characteristic lifetime for emissions in the author's opinion hides a scientific approximation. Integrated assessment models (IAMs) where economic and environmental consequences of policy are treated together involved simple box models of the carbon cycle but these introduce a great element of doubt into the IAMs. 8 refs

  10. Radon-calibrated emissions of CO2 from South Africa

    International Nuclear Information System (INIS)

    Gaudry, A.; Polian, G.; Ardouin, B.; Lambert, G.

    1990-01-01

    Atmospheric CO 2 and 222 Rn have been monitored at Amsterdam Island since 1980. Data were selected in order to eliminate any local influence. Typical CO 2 concentrations of the subantarctic marine atmosphere can be determined by selecting those values for which 222 Rn radioactivity was particularly low: less than 1 pCi m -3 . 222 Rn concentrations higher than 2 pCi m -3 are mainly due to injections into the subantarctic atmosphere from the continental source of South Africa. The passage of air masses under continental influence also shows typical CO 2 variations, well correlated with 222 Rn variations. From the knowledge of the global continental fluxes of 222 Rn, it has been possible to estimate CO 2 fluxes into the atmosphere from South Africa. The mean CO 2 flux corresponding to a 6-month period from May to October is about 5 millimole m -2 h -1 . Continental CO 2 emissions reach a maximum in August. (orig.)

  11. City density and CO_2 efficiency

    International Nuclear Information System (INIS)

    Gudipudi, Ramana; Fluschnik, Till; Ros, Anselmo García Cantú; Walther, Carsten; Kropp, Jürgen P.

    2016-01-01

    Cities play a vital role in the global climate change mitigation agenda. City population density is one of the key factors that influence urban energy consumption and the subsequent GHG emissions. However, previous research on the relationship between population density and GHG emissions led to contradictory results due to urban/rural definition conundrum and the varying methodologies for estimating GHG emissions. This work addresses these ambiguities by employing the City Clustering Algorithm (CCA) and utilizing the gridded CO_2 emissions data. Our results, derived from the analysis of all inhabited areas in the US, show a sub-linear relationship between population density and the total emissions (i.e. the sum of on-road and building emissions) on a per capita basis. Accordingly, we find that doubling the population density would entail a reduction in the total CO_2 emissions in buildings and on-road sectors typically by at least 42%. Moreover, we find that population density exerts a higher influence on on-road emissions than buildings emissions. From an energy consumption point of view, our results suggest that on-going urban sprawl will lead to an increase in on-road energy consumption in cities and therefore stresses the importance of developing adequate local policy measures to limit urban sprawl. - Highlights: •We use gridded population, land use and CO_2 emissions data. •We attribute building and on-road sectoral emissions to populated settlements. •We apply CCA to identify unique city extents and population densities. •Doubling the population density increases CO_2 efficiency typically by 42%. •Population density has more influence on-road CO_2 efficiency than buildings sector.

  12. Technical insight on the requirements for CO2-saturated growth of microalgae in photobioreactors.

    Science.gov (United States)

    Yuvraj; Padmanabhan, Padmini

    2017-06-01

    Microalgal cultures are usually sparged with CO 2 -enriched air to preclude CO 2 limitation during photoautotrophic growth. However, the CO 2 vol% specifically required at operating conditions to meet the carbon requirement of algal cells in photobioreactor is never determined and 1-10% v/v CO 2 -enriched air is arbitrarily used. A scheme is proposed and experimentally validated for Chlorella vulgaris that allows computing CO 2 -saturated growth feasible at given CO 2 vol% and volumetric O 2 mass-transfer coefficient (k L a) O . CO 2 sufficiency in an experiment can be theoretically established to adjust conditions for CO 2 -saturated growth. The methodology completely eliminates the requirement of CO 2 electrode for online estimation of dissolved CO 2 to determine critical CO 2 concentration (C crit ), specific CO 2 uptake rate (SCUR), and volumetric CO 2 mass-transfer coefficient (k L a) C required for the governing CO 2 mass-transfer equation. C crit was estimated from specific O 2 production rate (SOPR) measurements at different dissolved CO 2 concentrations. SCUR was calculated from SOPR and photosynthetic quotient (PQ) determined from the balanced stoichiometric equation of growth. Effect of light attenuation and nutrient depletion on biomass estimate is also discussed. Furthermore, a simple design of photosynthetic activity measurement system was used, which minimizes light attenuation by hanging a low depth (ca. 10 mm) culture over the light source.

  13. Studies on CO2-laser Hybrid-Welding of Copper

    DEFF Research Database (Denmark)

    Nielsen, Jakob Skov; Olsen, Flemming Ove; Bagger, Claus

    2005-01-01

    CO2-laser welding of copper is known to be difficult due to the high heat conductivity of the material and the high reflectivity of copper at the wavelength of the CO2-laser light. THis paper presents a study of laser welding of copper, applying laser hybrid welding. Welding was performed as a hy...

  14. Growth and control of invasive weeds under elevated CO2

    Science.gov (United States)

    Atmospheric concentrations of CO2 have been increasing since the onset of the industrial revolution. Regardless of the debate on the effects of this rise on climate, most plants exhibit a positive growth response to elevated CO2 due to increased photosynthesis, resource use efficiency, and/or alloca...

  15. On a CO2 ration

    International Nuclear Information System (INIS)

    De Wit, P.

    2003-01-01

    In 2 years all the large energy companies in the European Union will have a CO2 ration, including a system to trade a shortage or surplus of emission rights. A cost effective system to reduce emission, provided that the government does not auction the emission rights [nl

  16. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  17. THE INFLUENCE OF CO2 ON WELL CEMENT

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2010-12-01

    Full Text Available Carbon capture and storage is one way to reduce emissions of greenhouse gases in the atmosphere. Underground gas storage operations and CO2 sequestration in aquifers relay on both the proper wellbore construction and sealing properties of the cap rock. CO2 injection candidates may be new wells or old wells. In both cases, the long-term wellbore integrity (up to 1 000 years is one of the key performance criteria in the geological storage of CO2. The potential leakage paths are the migration CO2 along the wellbore due to poor cementation and flow through the cap rock. The permeability and integrity of the set cement will determine how effective it is in preventing the leakage. The integrity of the cap rock is assured by an adequate fracture gradient and by sufficient set cement around the casing across the cap rock and without a micro-annulus. CO2 storage in underground formations has revived the researc of long term influence of the injected CO2 on Portland cements and methods for improving the long term efficiency of the wellbore sealant. Some researchers predicted that set cement will fail when exposed to CO2 leading to potential leakage to the atmosphere or into underground formations that may contain potable water. Other researchers show set cement samples from 30 to 50 year-old wells (CO2 EOR projects that have maintained sealing integrity and prevented CO2 leakage, in spite of some degree of carbonation. One of reasons for the discrepancy between certain research lab tests and actual field performance measurements is the absence of standard protocol for CO2 resistance-testing devices, conditions, or procedures. This paper presents potential flow paths along the wellbore, CO2 behaviour under reservoir conditions, and geochemical alteration of hydrated Portland cement due to supercritical CO2 injection.

  18. Co2+ ion exchange with NaY

    International Nuclear Information System (INIS)

    Garcia, I.; Solache-Rios, M.; Bulbulian, S.; Bosch, P.

    1993-01-01

    Co 2+ ion exchange from aqueous cobalt chloride-sodium chloride solutions with NaY zeolite has been investigated. The effect of contact time on the sorption of Co 2+ by dehydrated Y zeolite at 150 degrees C is unusual. A fast sorption uptake is observed in which 1.73 mequiv/g of zeolite of Na + ions is replaced by cobalt ions, followed by a desorption process where the uptake decreases to 1.56 mequiv/g of zeolite. This behavior is explained by the location and coordination of cobalt in Y zeolite sites. It is suggested that the maximum uptake corresponds to cobalt ions being simultaneously in two sites; tetrahedrally coordinated in the sodalite units and octahedrally coordinated in the large cavities. It is also suggested that the desorption process is a consequence of a reaction between Cl - ions and the tetrahedral species. 20 refs., 4 figs

  19. Annual CO2 budget and seasonal CO2 exchange signals at a High Arctic permafrost site on Spitsbergen, Svalbard archipelago

    Science.gov (United States)

    Lüers, J.; Westermann, S.; Piel, K.; Boike, J.

    2014-01-01

    The annual variability of CO2 exchange in most ecosystems is primarily driven by the activities of plants and soil microorganisms. However, little is known about the carbon balance and its controlling factors outside the growing season in arctic regions dominated by soil freeze/thaw-processes, long-lasting snow cover, and several months of darkness. This study presents a complete annual cycle of the CO2 net ecosystem exchange (NEE) dynamics for a High Arctic tundra area on the west coast of Svalbard based on eddy-covariance flux measurements. The annual cumulative CO2 budget is close to zero grams carbon per square meter per year, but shows a very strong seasonal variability. Four major CO2 exchange seasons have been identified. (1) During summer (ground snow-free), the CO2 exchange occurs mainly as a result of biological activity, with a predominance of strong CO2 assimilation by the ecosystem. (2) The autumn (ground snow-free or partly snow-covered) is dominated by CO2 respiration as a result of biological activity. (3) In winter and spring (ground snow-covered), low but persistent CO2 release occur, overlain by considerable CO2 exchange events in both directions associated with changes of air masses and air and atmospheric CO2 pressure. (4) The snow melt season (pattern of snow-free and snow-covered areas), where both, meteorological and biological forcing, resulting in a visible carbon uptake by the high arctic ecosystem. Data related to this article are archived under: http://doi.pangaea.de/10.1594/PANGAEA.809507.

  20. Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

    Science.gov (United States)

    Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

    2014-01-01

    Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048–1079 and AD 1838–2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830–1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem. PMID:24888785

  1. Olivine Dissolution in Seawater: Implications for CO2 Sequestration through Enhanced Weathering in Coastal Environments

    Science.gov (United States)

    2017-01-01

    Enhanced weathering of (ultra)basic silicate rocks such as olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine weathering is expected to increase seawater alkalinity, thus resulting in additional CO2 uptake from the atmosphere. However, the mechanisms of marine olivine weathering and its effect on seawater–carbonate chemistry remain poorly understood. Here, we present results from batch reaction experiments, in which forsteritic olivine was subjected to rotational agitation in different seawater media for periods of days to months. Olivine dissolution caused a significant increase in alkalinity of the seawater with a consequent DIC increase due to CO2 invasion, thus confirming viability of the basic concept of enhanced silicate weathering. However, our experiments also identified several important challenges with respect to the detailed quantification of the CO2 sequestration efficiency under field conditions, which include nonstoichiometric dissolution, potential pore water saturation in the seabed, and the potential occurrence of secondary reactions. Before enhanced weathering of olivine in coastal environments can be considered an option for realizing negative CO2 emissions for climate mitigation purposes, these aspects need further experimental assessment. PMID:28281750

  2. Effect of membrane on carbonation and carbon dioxide uptake of Chlorella sp.

    Directory of Open Access Journals (Sweden)

    Suali Emma

    2017-01-01

    Full Text Available Recent studies showed that as low as 5% CO2 increased microalgae growth. However, common bioreactor operation resulted in low carbonation due to poor CO2 mass transfer and this inhibited CO2 uptake of microalgae. Although bubbling increases mass transfer of CO2-O2 exchange, preserving high dissolved CO2 remains the most challenging of microalgae cultivation in bioreactor. In order to increase high dissolved CO2 and CO2-O2 exchange, this study employed two types of membrane; hollow-fibre membrane for carbonation and hydrophobic membrane for deoxygenation. It was found that membrane increased carbonation from 20 % to 75 % when operated at control CO2 concentration. The hollow-fibre membrane capable of creating as small as 2 mm bubble which effective for high carbonation. At the same time, itincreased CO2 uptake up to 85% in bioreactor. The hydrophobic membrane removed 43% O2 from the bioreactor. Both membranes increased mass transfer of CO2-O2 exchange in bioreactor which stimulated microalgae growth.

  3. Sustainable Process Networks for CO2 Conversion

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Kongpanna, P.; Pavarajam, V.

    According to various organizations, especially the Intergovernmental Panel on Climate Change, global warming is an ever-increasing threat to the environment and poses a problem if not addressed. As a result, efforts are being made across academic and industrial fields to find methods of reducing...... drawbacks to this geologic storage system: the CO2 is not eliminated, the implementation is limited due to natural phenomena, and the capturing methods are often expensive. Thus, it is desirable to develop an alternative strategy for reducing the CO2 emissions [2]. An additional process that reduces...... that are thermodynamically feasible, including the co-reactants, catalysts, operating conditions and reactions. Research has revealed that there are a variety of reactions that fulfill the aforementioned criteria. The products that are formed fall into categories: fuels, bulk chemicals and specialty chemicals. While fuels...

  4. The acceleration of dissolved cobalt's ecological stoichiometry due to biological uptake, remineralization, and scavenging in the Atlantic Ocean

    Science.gov (United States)

    Saito, Mak A.; Noble, Abigail E.; Hawco, Nicholas; Twining, Benjamin S.; Ohnemus, Daniel C.; John, Seth G.; Lam, Phoebe; Conway, Tim M.; Johnson, Rod; Moran, Dawn; McIlvin, Matthew

    2017-10-01

    The stoichiometry of biological components and their influence on dissolved distributions have long been of interest in the study of the oceans. Cobalt has the smallest oceanic inventory of inorganic micronutrients and hence is particularly vulnerable to influence by internal oceanic processes including euphotic zone uptake, remineralization, and scavenging. Here we observe not only large variations in dCo : P stoichiometry but also the acceleration of those dCo : P ratios in the upper water column in response to several environmental processes. The ecological stoichiometry of total dissolved cobalt (dCo) was examined using data from a US North Atlantic GEOTRACES transect and from a zonal South Atlantic GEOTRACES-compliant transect (GA03/3e and GAc01) by Redfieldian analysis of its statistical relationships with the macronutrient phosphate. Trends in the dissolved cobalt to phosphate (dCo : P) stoichiometric relationships were evident in the basin-scale vertical structure of cobalt, with positive dCo : P slopes in the euphotic zone and negative slopes found in the ocean interior and in coastal environments. The euphotic positive slopes were often found to accelerate towards the surface and this was interpreted as being due to the combined influence of depleted phosphate, phosphorus-sparing (conserving) mechanisms, increased alkaline phosphatase metalloenzyme production (a zinc or perhaps cobalt enzyme), and biochemical substitution of Co for depleted Zn. Consistent with this, dissolved Zn (dZn) was found to be drawn down to only 2-fold more than dCo, despite being more than 18-fold more abundant in the ocean interior. Particulate cobalt concentrations increased in abundance from the base of the euphotic zone to become ˜ 10 % of the overall cobalt inventory in the upper euphotic zone with high stoichiometric values of ˜ 400 µmol Co mol-1 P. Metaproteomic results from the Bermuda Atlantic Time-series Study (BATS) station found cyanobacterial isoforms of the

  5. Biofiksasi CO2 Oleh Mikroalga Chlamydomonas sp dalam Photobioreaktor Tubular

    Directory of Open Access Journals (Sweden)

    Hadiyanto Hadiyanto

    2014-05-01

    algal biomass and the maximum algae growth rate occurred at 0.31 / day. At a concentration of 30% CO2 gas, it occurs a substrate inhibition due to inefficient of bicarbonate use by algae culture.

  6. Global energy / CO2 projections

    International Nuclear Information System (INIS)

    Sinyak, Y.

    1990-09-01

    Section headings are: (1) Social and economic problems of the 21 st century and the role of energy supply systems (2) Energy-environment interactions as a central point of energy research activities (3) New ways of technological progress and its impacts on energy demand and supply (4) Long-term global energy projections (5) Comparative analysis of global long-term energy / CO 2 studies (6) Conclusions. The author shows that, in order to alleviate the negative impacts of energy systems on the climate, it will be necessary to undertake tremendous efforts to improve the energy use efficiency, to drastically change the primary energy mix, and, at the same time, to take action to reduce greenhouse emissions from other sources and increase the CO 2 sink through enhanced reforestation. (Quittner)

  7. CO2 Acquisition Membrane (CAM)

    Science.gov (United States)

    Mason, Larry W.; Way, J. Douglas; Vlasse, Marcus

    2003-01-01

    The objective of CAM is to develop, test, and analyze thin film membrane materials for separation and purification of carbon dioxide (CO2) from mixtures of gases, such as those found in the Martian atmosphere. The membranes are targeted toward In Situ Resource Utilization (ISRU) applications that will operate in extraterrestrial environments and support future unmanned and human space missions. A primary application is the Sabatier Electrolysis process that uses Mars atmosphere CO2 as raw material for producing water, oxygen, and methane for rocket fuel and habitat support. Other applications include use as an inlet filter to collect and concentrate Mars atmospheric argon and nitrogen gases for habitat pressurization, and to remove CO2 from breathing gases in Closed Environment Life Support Systems (CELSS). CAM membrane materials include crystalline faujasite (FAU) zeolite and rubbery polymers such as silicone rubber (PDMS) that have been shown in the literature and via molecular simulation to favor adsorption and permeation of CO2 over nitrogen and argon. Pure gas permeation tests using commercial PDMS membranes have shown that both CO2 permeance and the separation factor relative to other gases increase as the temperature decreases, and low (Delta)P(Sub CO2) favors higher separation factors. The ideal CO2/N2 separation factor increases from 7.5 to 17.5 as temperature decreases from 22 C to -30 C. For gas mixtures containing CO2, N2, and Ar, plasticization decreased the separation factors from 4.5 to 6 over the same temperature range. We currently synthesize and test our own Na(+) FAU zeolite membranes using standard formulations and secondary growth methods on porous alumina. Preliminary tests with a Na(+) FAU membrane at 22 C show a He/SF6 ideal separation factor of 62, exceeding the Knudsen diffusion selectivity by an order of magnitude. This shows that the membrane is relatively free from large defects and associated non-selective (viscous flow) transport

  8. Fang CO2 med Aminosyrer

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai

    2010-01-01

    Med såkaldte “carbon capture-teknikker” er det muligt at rense røgen fra kulfyrede kraftværker, således at den er næsten helt fri for drivhusgassen CO2. Kunsten er at gøre processen tilstrækkeligt billig. Et lovende fangstredskab i denne proces er aminosyrer.......Med såkaldte “carbon capture-teknikker” er det muligt at rense røgen fra kulfyrede kraftværker, således at den er næsten helt fri for drivhusgassen CO2. Kunsten er at gøre processen tilstrækkeligt billig. Et lovende fangstredskab i denne proces er aminosyrer....

  9. Atmospheric CO2 Variability Observed From ASCENDS Flight Campaigns

    Science.gov (United States)

    Lin, Bing; Browell, Edward; Campbell, Joel; Choi, Yonghoon; Dobler, Jeremy; Fan, Tai-Fang; Harrison, F. Wallace; Kooi, Susan; Liu, Zhaoyan; Meadows, Byron; hide

    2015-01-01

    Significant atmospheric CO2 variations on various spatiotemporal scales were observed during ASCENDS flight campaigns. For example, around 10-ppm CO2 changes were found within free troposphere in a region of about 200x300 sq km over Iowa during a summer 2014 flight. Even over extended forests, about 2-ppm CO2 column variability was measured within about 500-km distance. For winter times, especially over snow covered ground, relatively less horizontal CO2 variability was observed, likely owing to minimal interactions between the atmosphere and land surface. Inter-annual variations of CO2 drawdown over cornfields in the Mid-West were found to be larger than 5 ppm due to slight differences in the corn growing phase and meteorological conditions even in the same time period of a year. Furthermore, considerable differences in atmospheric CO2 profiles were found during winter and summer campaigns. In the winter CO2 was found to decrease from about 400 ppm in the atmospheric boundary layer (ABL) to about 392 ppm above 10 km, while in the summer CO2 increased from 386 ppm in the ABL to about 396 ppm in free troposphere. These and other CO2 observations are discussed in this presentation.

  10. CO2 reduction by dematerialization

    Energy Technology Data Exchange (ETDEWEB)

    Hekkert, M.P. [Department of Innovation Studies, Copernicus Institute, Utrecht University, Utrecht (Netherlands)

    2002-04-01

    Current policy for the reduction of greenhouse gases is mainly concerned with a number of types of solutions: energy saving, shifting to the use of low-carbon fuels and the implementation of sustainable energy technologies. Recent research has shown that a strategy directed at a more efficient use of materials could make a considerable contribution to reducing CO2 emissions. Moreover, the costs to society as a whole of such a measure appear to be very low.

  11. Outsourcing CO2 within China.

    Science.gov (United States)

    Feng, Kuishuang; Davis, Steven J; Sun, Laixiang; Li, Xin; Guan, Dabo; Liu, Weidong; Liu, Zhu; Hubacek, Klaus

    2013-07-09

    Recent studies have shown that the high standard of living enjoyed by people in the richest countries often comes at the expense of CO2 emissions produced with technologies of low efficiency in less affluent, developing countries. Less apparent is that this relationship between developed and developing can exist within a single country's borders, with rich regions consuming and exporting high-value goods and services that depend upon production of low-cost and emission-intensive goods and services from poorer regions in the same country. As the world's largest emitter of CO2, China is a prominent and important example, struggling to balance rapid economic growth and environmental sustainability across provinces that are in very different stages of development. In this study, we track CO2 emissions embodied in products traded among Chinese provinces and internationally. We find that 57% of China's emissions are related to goods that are consumed outside of the province where they are produced. For instance, up to 80% of the emissions related to goods consumed in the highly developed coastal provinces are imported from less developed provinces in central and western China where many low-value-added but high-carbon-intensive goods are produced. Without policy attention to this sort of interprovincial carbon leakage, the less developed provinces will struggle to meet their emissions intensity targets, whereas the more developed provinces might achieve their own targets by further outsourcing. Consumption-based accounting of emissions can thus inform effective and equitable climate policy within China.

  12. Hydrothermal Valorization of Steel Slags—Part I: Coupled H2 Production and CO2 Mineral Sequestration

    Directory of Open Access Journals (Sweden)

    Camille Crouzet

    2017-10-01

    Full Text Available A new process route for the valorization of BOF steel slags combining H2 production and CO2 mineral sequestration is investigated at 300°C (HT under hydrothermal conditions. A BOF steel slag stored several weeks outdoor on the production site was used as starting material. To serve as a reference, room temperature (RT carbonation of the same BOF steel slag has been monitored with in situ Raman spectroscopy and by measuring pH and PCO2 on a time-resolved basis. CO2 uptake under RT and HT are, respectively, 243 and 327 kg CO2/t of fresh steel slag, which add up with the 63 kg of atmospheric CO2 per ton already uptaken by the starting steel slag on the storage site. The CO2 gained by the sample at HT is bounded to the carbonation of brownmillerite. H2 yield decreased by about 30% in comparison to the same experiment performed without added CO2, due to sequestration of ferrous iron in a Mg-rich siderite phase. Ferric iron, initially present in brownmillerite, is partitioned between an Fe-rich clay mineral of saponite type and metastable hematite. Saponite is likely stabilized by the presence of Al, whereas hematite may represent a metastable product of brownmillerite carbonation. Mg-rich wüstite is involved in at least two competing reactions, i.e., oxidation into magnetite and carbonation into siderite. Results of both water-slag and water-CO2-slag experiments after 72 h are consistent with a kinetics enhancement of the former reaction when a CO2 partial pressure imposes a pH between 5 and 6. Three possible valorization routes, (1 RT carbonation prior to hydrothermal oxidation, (2 RT carbonation after hydrothermal treatment, and (3 combined HT carbonation and oxidation are discussed in light of the present results and literature data.

  13. Optimizing CO2 avoided cost by means of repowering

    International Nuclear Information System (INIS)

    Escosa, Jesus M.; Romeo, Luis M.

    2009-01-01

    Repowering fossil fuel power plants by means of gas turbines has been traditionally considered to increase power output and reduce NO x and SO 2 emissions both at low cost and short outage periods. At present, reduction in CO 2 emissions represents an additional advantage of repowering due to partial fuel shift and overall efficiency increase. This is especially important in existing installations with a CO 2 reduction mandatory that should be carried out in a short time and in a cost-effective manner. Feedwater and parallel repowering schemes have been analysed using thermodynamic, environmental and economic simulations. The objective is not only to evaluate the cost of electricity and the efficiency increase of the overall system, but calculate and minimize the cost of CO 2 avoided as a function of gas turbine power output. It seems that integration of larger gas turbines reduces the overall CO 2 emissions, but there is a compromise between CO 2 reduction due to fuel shift and a optimum integration of waste heat into the power plant to minimize the CO 2 avoided costs. Results highlight the repowering as a suitable technology to reduce 10-30% of CO 2 emissions in existing power plants with cost well below 20 Euro /tCO 2 . It could help to control emissions up to the carbon capture technologies commercial development.

  14. Simulasi Numeris Karakteristik Pembakaran CH4/CO2/Udara dan CH4/CO2/O2 pada Counterflow Premixed Burner

    Directory of Open Access Journals (Sweden)

    Hangga Wicaksono

    2017-08-01

    Full Text Available The high amount of CO2 produced in a conventional biogas reactor needs to be considered. A further analysis is needed in order to investigate the effect of CO2 addition especially in thermal and chemical kinetics aspect. This numerical study has been held to analyze the effect of CO2 in CH4/CO2/O­2 and CH4/CO2/Air premixed combustion. In this study one dimensional analisys in a counterflow burner has been performed. The volume fraction of CO2 used in this study was 0%-40% from CH4’s volume fraction, according to the amount of CO2 in general phenomenon. Based on the flammability limits data, the volume fraction of CH4 used was 5-61% in O2 environment and 5-15% in air environment. The results showed a decreasing temperature along with the increasing percentage of CO2 in each mixtures, but the effect was quite smaller especially in stoichiometric and lean mixture. CO2 could affects thermally (by absorbing heat due to its high Cp and also made the production of unburnt fuel species such as CO relatively higher.

  15. CO2 emissions: a peak level in 2010

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    After a reduction of CO 2 emissions in 2009 due to the financial crisis, these emissions have again reached a peak in 2010: 30.6 Gt, it means an increase by 5% compared to the previous peak. According to IEA (International Energy Agency): 44% of the emissions come from coal, 36% from oil and 20% from natural gas, and OECD countries are responsible of 40% of the CO 2 global emissions but only of 25% of their increase since 2009. For China and India the emissions of CO 2 have increased sharply due to their strong economic growth. (A.C.)

  16. Aridity under conditions of increased CO2

    Science.gov (United States)

    Greve, Peter; Roderick, Micheal L.; Seneviratne, Sonia I.

    2016-04-01

    A string of recent of studies led to the wide-held assumption that aridity will increase under conditions of increasing atmospheric CO2 concentrations and associated global warming. Such results generally build upon analyses of changes in the 'aridity index' (the ratio of potential evaporation to precipitation) and can be described as a direct thermodynamic effect on atmospheric water demand due to increasing temperatures. However, there is widespread evidence that contradicts the 'warmer is more arid' interpretation, leading to the 'global aridity paradox' (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment of modeled changes in a broad set of dryness metrics (primarily based on a range of measures of water availability) over a large range of realistic atmospheric CO2 concentrations. We use an ensemble of simulations from of state-of-the-art climate models to analyse both equilibrium climate experiments and transient historical simulations and future projections. Our results show that dryness is, under conditions of increasing atmospheric CO2 concentrations and related global warming, generally decreasing at global scales. At regional scales we do, however, identify areas that undergo changes towards drier conditions, located primarily in subtropical climate regions and the Amazon Basin. Nonetheless, the majority of regions, especially in tropical and mid- to northern high latitudes areas, display wetting conditions in a warming world. Our results contradict previous findings and highlight the need to comprehensively assess all aspects of changes in hydroclimatological conditions at the land surface. Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463

  17. Capture, transport and storage of CO2

    International Nuclear Information System (INIS)

    De Boer, B.

    2008-01-01

    The emission of greenhouse gas CO2 in industrial processes and electricity production can be reduced on a large scale. Available techniques include post-combustion, pre-combustion, the oxy-fuel process, CO2 fixation in industrial processes and CO2 mineralization. In the Netherlands, plans for CO2 capture are not developing rapidly (CCS - carbon capture and storage). [mk] [nl

  18. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

  19. Recent global CO2 flux inferred from atmospheric CO2 observations and its regional analyses

    Directory of Open Access Journals (Sweden)

    J. M. Chen

    2011-11-01

    Full Text Available The net surface exchange of CO2 for the years 2002–2007 is inferred from 12 181 atmospheric CO2 concentration data with a time-dependent Bayesian synthesis inversion scheme. Monthly CO2 fluxes are optimized for 30 regions of the North America and 20 regions for the rest of the globe. Although there have been many previous multiyear inversion studies, the reliability of atmospheric inversion techniques has not yet been systematically evaluated for quantifying regional interannual variability in the carbon cycle. In this study, the global interannual variability of the CO2 flux is found to be dominated by terrestrial ecosystems, particularly by tropical land, and the variations of regional terrestrial carbon fluxes are closely related to climate variations. These interannual variations are mostly caused by abnormal meteorological conditions in a few months in the year or part of a growing season and cannot be well represented using annual means, suggesting that we should pay attention to finer temporal climate variations in ecosystem modeling. We find that, excluding fossil fuel and biomass burning emissions, terrestrial ecosystems and oceans absorb an average of 3.63 ± 0.49 and 1.94 ± 0.41 Pg C yr−1, respectively. The terrestrial uptake is mainly in northern land while the tropical and southern lands contribute 0.62 ± 0.47, and 0.67 ± 0.34 Pg C yr−1 to the sink, respectively. In North America, terrestrial ecosystems absorb 0.89 ± 0.18 Pg C yr−1 on average with a strong flux density found in the south-east of the continent.

  20. Negative CO2 emissions via subsurface mineral carbonation in fractured peridotite

    Science.gov (United States)

    Kelemen, P. B.; Matter, J.

    2014-12-01

    Uptake of CO2 from surface water via mineral carbonation in peridotite can be engineered to achieve negative CO2 emissions. Reaction with peridotite, e.g., CO2 + olivine (A), serpentine (B) and brucite (C), forms inert, non-toxic, solid carbonates such as magnesite. Experimental studies show that A can be 80% complete in a few hours with 30 micron powders and elevated P(CO2) [1,2,3]. B is slower, but in natural systems the rate of B+C is significant [4]. Methods for capture of dilute CO2 via mineral carbonation [4,5,6,7] are not well known, though CO2 storage via mineral carbonation has been discussed for decades [8,9]. Where crushed peridotite is available, as in mine tailings, increased air or water flow could enhance CO2 uptake at a reasonable cost [4,5]. Here we focus on enhancing subsurface CO2 uptake from surface water flowing in fractured peridotite, in systems driven by thermal convection such as geothermal power plants. Return of depleted water to the surface would draw down CO2 from the air [6,7]. CO2 uptake from water, rate limited by flow in input and output wells, could exceed 1000 tons CO2/yr [7]. If well costs minus power sales were 0.1M to 1M and each system lasts 10 years this costs oil industry. Uptake of 1 Gt CO2/yr at 1000 t/well/yr requires 1M wells, comparable to the number of producing oil and gas wells in the USA. Subsurface CO2 uptake could first be applied in coastal, sub-seafloor peridotite with onshore drilling. Sub-seafloor peridotite is extensive off Oman, New Caledonia and Papua New Guinea, with smaller amounts off Spain, Morocco, USA, etc. This would be a regional contribution, used in parallel with other methods elsewhere. To achieve larger scale is conceivable. There is a giant mass of seafloor peridotite along slow-spreading mid-ocean ridges. Could robotic drills enhance CO2 uptake at a reasonable cost, while fabric chimneys transport CO2-depleted water to the sea surface? Does anyone know James Cameron's phone number? [1] O

  1. Leakage and Seepage of CO2 from Geologic Carbon Sequestration Sites: CO2 Migration into Surface Water

    International Nuclear Information System (INIS)

    Oldenburg, Curt M.; Lewicki, Jennifer L.

    2005-01-01

    Geologic carbon sequestration is the capture of anthropogenic carbon dioxide (CO 2 ) and its storage in deep geologic formations. One of the concerns of geologic carbon sequestration is that injected CO 2 may leak out of the intended storage formation, migrate to the near-surface environment, and seep out of the ground or into surface water. In this research, we investigate the process of CO 2 leakage and seepage into saturated sediments and overlying surface water bodies such as rivers, lakes, wetlands, and continental shelf marine environments. Natural CO 2 and CH 4 fluxes are well studied and provide insight into the expected transport mechanisms and fate of seepage fluxes of similar magnitude. Also, natural CO 2 and CH 4 fluxes are pervasive in surface water environments at levels that may mask low-level carbon sequestration leakage and seepage. Extreme examples are the well known volcanic lakes in Cameroon where lake water supersaturated with respect to CO 2 overturned and degassed with lethal effects. Standard bubble formation and hydrostatics are applicable to CO 2 bubbles in surface water. Bubble-rise velocity in surface water is a function of bubble size and reaches a maximum of approximately 30 cm s -1 at a bubble radius of 0.7 mm. Bubble rise in saturated porous media below surface water is affected by surface tension and buoyancy forces, along with the solid matrix pore structure. For medium and fine grain sizes, surface tension forces dominate and gas transport tends to occur as channel flow rather than bubble flow. For coarse porous media such as gravels and coarse sand, buoyancy dominates and the maximum bubble rise velocity is predicted to be approximately 18 cm s -1 . Liquid CO 2 bubbles rise slower in water than gaseous CO 2 bubbles due to the smaller density contrast. A comparison of ebullition (i.e., bubble formation) and resulting bubble flow versus dispersive gas transport for CO 2 and CH 4 at three different seepage rates reveals that

  2. Impact of renewables deployment on the CO2 price and the CO2 emissions in the European electricity sector

    International Nuclear Information System (INIS)

    Van den Bergh, Kenneth; Delarue, Erik; D'haeseleer, William

    2013-01-01

    As of 2005, electricity generators in Europe operate under the European Union Emission Trading System (EU ETS). At the same time, European Member States have launched support mechanisms to stimulate the deployment of renewable electricity sources (RES-E). RES-E injections displace CO 2 emissions within the sectors operating under the EU ETS and they reduce the demand for European Union Allowances (EUAs), thereby reducing the EUA price. This paper presents the results of an ex post analysis to quantify the impact of RES-E deployment on the EUA price and CO 2 emissions in the Western and Southern European electricity sector during the period from 2007 to 2010, following from an operational partial equilibrium model of the electricity sector. This study shows that the CO 2 displacement from the electricity sector to other ETS sectors due to RES-E deployment can be up to more than 10% of historical CO 2 emissions in the electricity sector. The EUA price decrease caused by RES-E deployment turns out to be likely significant. - Author-Highlights: • We assessed the impact of renewables deployment in the period 2007–2010. • Impact on CO 2 emissions in the electricity sector and the CO 2 price is considered. • CO 2 emissions decreased by up to 10% of historical emissions. • CO 2 price decrease due to renewables turns out to be likely significant

  3. Reduced 99mTc labelled NCA-95/CEA-antibody uptake in liver due to gentle antibody reconstitution

    International Nuclear Information System (INIS)

    Reske, S.N.; Buell, U.

    1990-01-01

    The influence of reconstituting a murine monoclonal IgG 1 antibody kit with pertechnetate Tc99m on antibody distribution in the liver, spleen and sternal bone marrow of patients was examined. The 99m Tc-labelled antibody used is directed against non-specific cross-reacting antigen (NCA-95) and carcinoembryonic antigen (CEA) and has been successfully applied for imaging tissue inflammation and bone marrow scanning. Radioactivity uptake was determined in the liver, spleen, bone marrow and a precordial background region in a consecutive series of 25 patients, examined with an antibody preparation, routinely radiolabelled according to the manufacturer's recommendations and in 14 patients, in whom the antibody was reconstituted with special care, avoiding bubble formation and dropping of buffer into the antibody-containing vial. Gentle compared with routine antibody reconstitution caused a highly significant reduction of the antibody uptake in the liver, as determined by count densities, normalized to injected dose and acquisition time (13.2±5.5 vs 20.1±6.0 cpm per pixel, anti x±SD, P=0.008). The liver to background ratio was reduced from 3.4±1.4 to 1.9±0.5 (P<0.001). Spleen, sternal bone marrow and precordial background count rates were not significantly affected. These results clearly demonstrate that gentle antibody reconstitution can decrease non-specific antibody uptake in the liver by 34%±6.4% (anti x±SEM). Thus, scan quality is improved, and the potential deleterious camouflage of underlying structures is avoided. (orig.)

  4. RODZAJE METOD SEKWESTRACJI CO2

    Directory of Open Access Journals (Sweden)

    Zofia LUBAŃSKA

    Full Text Available Z pojęciem ochrony środowiska wiąże się bardzo szeroko w ostatnim czasie omawiane zagadnienie dotyczące ograniczenia emisji CO2. Konsekwencją globalnych zmian klimatu wywołanego przez ludzi jest wzrost stężenia atmosferycznego gazów cieplarnianych, które powodują nasilający się efekt cieplarniany. Wzrasta na świecie liczba ludności, a co za tym idzie wzrasta konsumpcja na jednego mieszkańca, szczególnie w krajach szeroko rozwiniętych gospodarczo. Protokół z Kioto ściśle określa działania jakie należy podjąć w celu zmniejszenia stężenia dwutlenku węgla w atmosferze. Pomimo maksymalnej optymalizacji procesu spalania paliw kopalnianych wykorzystywanych do produkcji energii, zastosowania odnawialnych źródeł energii zmiana klimatu jest nieunikniona i konsekwentnie będzie postępować przez kolejne dekady. Prognozuje się, że duże znaczenie odegra nowoczesna technologia, która ma za zadanie wychwycenie CO2 a następnie składowanie go w odpowiednio wybranych formacjach geologicznych (CCS- Carbon Capture and Storage. Eksperci są zgodni, że ta technologia w niedalekiej przyszłości stanie się rozwiązaniem pozwalającym ograniczyć ogromną ilość emisji CO2 pochodzącą z procesów wytwarzania energii z paliw kopalnych. Z analiz Raportu IPCC wynika, iż technologia CSS może się przyczynić do ok. 20% redukcji emisji dwutlenku węgla przewidzianej do 2050 roku [3]. Zastosowanie jej napotyka na wiele barier, nie tylko technologicznych i ekonomicznych, ale także społecznych. Inną metodą dającą ujemne źródło emisji CO2 jest możliwość wykorzystania obszarów leśnych o odpowiedniej strukturze drzewostanu. Środkiem do tego celu, oprócz ograniczenia zużycia emisjogennych paliw kopalnych (przy zachowaniu zasad zrównoważonego rozwoju może być intensyfikacja zalesień. Zwiększanie lesistości i prawidłowa gospodarka leśna należy do najbardziej efektywnych sposobów kompensowania

  5. Dolomite decomposition under CO2

    International Nuclear Information System (INIS)

    Guerfa, F.; Bensouici, F.; Barama, S.E.; Harabi, A.; Achour, S.

    2004-01-01

    Full text.Dolomite (MgCa (CO 3 ) 2 is one of the most abundant mineral species on the surface of the planet, it occurs in sedimentary rocks. MgO, CaO and Doloma (Phase mixture of MgO and CaO, obtained from the mineral dolomite) based materials are attractive steel-making refractories because of their potential cost effectiveness and world wide abundance more recently, MgO is also used as protective layers in plasma screen manufacture ceel. The crystal structure of dolomite was determined as rhombohedral carbonates, they are layers of Mg +2 and layers of Ca +2 ions. It dissociates depending on the temperature variations according to the following reactions: MgCa (CO 3 ) 2 → MgO + CaO + 2CO 2 .....MgCa (CO 3 ) 2 → MgO + Ca + CaCO 3 + CO 2 .....This latter reaction may be considered as a first step for MgO production. Differential thermal analysis (DTA) are used to control dolomite decomposition and the X-Ray Diffraction (XRD) was used to elucidate thermal decomposition of dolomite according to the reaction. That required samples were heated to specific temperature and holding times. The average particle size of used dolomite powders is 0.3 mm, as where, the heating temperature was 700 degree celsius, using various holding times (90 and 120 minutes). Under CO 2 dolomite decomposed directly to CaCO 3 accompanied by the formation of MgO, no evidence was offered for the MgO formation of either CaO or MgCO 3 , under air, simultaneous formation of CaCO 3 , CaO and accompanied dolomite decomposition

  6. Outsourcing CO2 within China

    Science.gov (United States)

    Feng, Kuishuang; Davis, Steven J.; Sun, Laixiang; Li, Xin; Guan, Dabo; Liu, Weidong; Liu, Zhu; Hubacek, Klaus

    2013-01-01

    Recent studies have shown that the high standard of living enjoyed by people in the richest countries often comes at the expense of CO2 emissions produced with technologies of low efficiency in less affluent, developing countries. Less apparent is that this relationship between developed and developing can exist within a single country’s borders, with rich regions consuming and exporting high-value goods and services that depend upon production of low-cost and emission-intensive goods and services from poorer regions in the same country. As the world’s largest emitter of CO2, China is a prominent and important example, struggling to balance rapid economic growth and environmental sustainability across provinces that are in very different stages of development. In this study, we track CO2 emissions embodied in products traded among Chinese provinces and internationally. We find that 57% of China’s emissions are related to goods that are consumed outside of the province where they are produced. For instance, up to 80% of the emissions related to goods consumed in the highly developed coastal provinces are imported from less developed provinces in central and western China where many low–value-added but high–carbon-intensive goods are produced. Without policy attention to this sort of interprovincial carbon leakage, the less developed provinces will struggle to meet their emissions intensity targets, whereas the more developed provinces might achieve their own targets by further outsourcing. Consumption-based accounting of emissions can thus inform effective and equitable climate policy within China. PMID:23754377

  7. Is guava phenolic metabolism influenced by elevated atmospheric CO2?

    Science.gov (United States)

    Mendes de Rezende, Fernanda; Pereira de Souza, Amanda; Silveira Buckeridge, Marcos; Maria Furlan, Cláudia

    2015-01-01

    Seedlings of Psidium guajava cv. Pedro Sato were distributed into four open-top chambers: two with ambient CO(2) (∼390 ppm) and two with elevated CO(2) (∼780 ppm). Monthly, five individuals of each chamber were collected, separated into root, stem and leaves and immediately frozen in liquid nitrogen. Chemical parameters were analyzed to investigate how guava invests the surplus carbon. For all classes of phenolic compounds analyzed only tannins showed significant increase in plants at elevated CO(2) after 90 days. There was no significant difference in dry biomass, but the leaves showed high accumulation of starch under elevated CO(2). Results suggest that elevated CO(2) seems to be favorable to seedlings of P. guajava, due to accumulation of starch and tannins, the latter being an important anti-herbivore substance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. A joint global carbon inversion system using both CO2 and 13CO2 atmospheric concentration data

    Science.gov (United States)

    Chen, Jing M.; Mo, Gang; Deng, Feng

    2017-03-01

    Observations of 13CO2 at 73 sites compiled in the GLOBALVIEW database are used for an additional constraint in a global atmospheric inversion of the surface CO2 flux using CO2 observations at 210 sites (62 collocated with 13CO2 sites) for the 2002-2004 period for 39 land regions and 11 ocean regions. This constraint is implemented using prior CO2 fluxes estimated with a terrestrial ecosystem model and an ocean model. These models simulate 13CO2 discrimination rates of terrestrial photosynthesis and ocean-atmosphere diffusion processes. In both models, the 13CO2 disequilibrium between fluxes to and from the atmosphere is considered due to the historical change in atmospheric 13CO2 concentration. This joint inversion system using both13CO2 and CO2 observations is effectively a double deconvolution system with consideration of the spatial variations of isotopic discrimination and disequilibrium. Compared to the CO2-only inversion, this 13CO2 constraint on the inversion considerably reduces the total land carbon sink from 3.40 ± 0.84 to 2.53 ± 0.93 Pg C year-1 but increases the total oceanic carbon sink from 1.48 ± 0.40 to 2.36 ± 0.49 Pg C year-1. This constraint also changes the spatial distribution of the carbon sink. The largest sink increase occurs in the Amazon, while the largest source increases are in southern Africa, and Asia, where CO2 data are sparse. Through a case study, in which the spatial distribution of the annual 13CO2 discrimination rate over land is ignored by treating it as a constant at the global average of -14. 1 ‰, the spatial distribution of the inverted CO2 flux over land was found to be significantly modified (up to 15 % for some regions). The uncertainties in our disequilibrium flux estimation are 8.0 and 12.7 Pg C year-1 ‰ for land and ocean, respectively. These uncertainties induced the unpredictability of 0.47 and 0.54 Pg C year-1 in the inverted CO2 fluxes for land and ocean, respectively. Our joint inversion system is therefore

  9. Neither elevated nor reduced CO2 affects the photophysiological performance of the marine Antarctic diatom Chaetoceros brevis

    NARCIS (Netherlands)

    Boelen, Peter; de Poll, Willem H. van; van der Strate, Han J.; Neven, Ika A.; Beardall, John; Buma, Anita G. J.

    2011-01-01

    Enhanced or reduced pCO(2) (partial pressure of CO2) may affect the photosynthetic performance of marine microalgae since changes in pCO(2) can influence the activity of carbon concentrating mechanisms, modulate cellular RuBisCO levels or alter carbon uptake efficiency. In the present study we

  10. The fluid flow consequences of CO2 migration from 1000 to 600 metres upon passing the critical conditions of CO2

    NARCIS (Netherlands)

    Meer, L.G.H.; Hofstee, C.; Orlic, B.

    2009-01-01

    The minimum injection depth for the storage of CO2 is normally set at 800 metres. At and beyond this depth in the subsurface conditions exist where CO2 is in a so-called critical state. The supercritical CO2 has a viscosity comparable to that of a normal gas and a liquid-like density, Due to the

  11. Trading CO2 emission; Verhandelbaarheid van CO2-emissies

    Energy Technology Data Exchange (ETDEWEB)

    De Waal, J.F.; Looijenga, A.; Moor, R.; Wissema, E.W.J. [Afdeling Energie, Ministerie van VROM, The Hague (Netherlands)

    2000-06-01

    Systems for CO2-emission trading can take many shapes as developments in Europe show. European developments for emission trading tend to comprehend cap and-trade systems for large emission sources. In the Netherlands a different policy is in preparation. A trading system for sheltered sectors with an option to buy reductions from exposed sectors will be further developed by a Commission, appointed by the minister of environment. Exposed sectors are committed to belong to the top of the world on the area of energy-efficiency. The authors point out that a cap on the distribution of energy carriers natural gas, electricity and fuel seems to be an interesting option to shape the trade scheme. A cap on the distribution of electricity is desirable, but not easy to implement. The possible success of the system depends partly on an experiment with emission reductions. 10 refs.

  12. Forest response to elevated CO2 is conserved across a broad range of productivity

    Science.gov (United States)

    R. Norby; E. DeLucia; B. Gielen; C. Calfapietra; C. Giardina; J. King; J. Ledford; H. McCarthy; D. Moore; R. Ceulemans; P. De Angelis; A. C. Finzi; D. F. Karnosky; M. E. Kubiske; M. Lukac; K. S. Pregitzer; G. E. Scarascia-Mugnozza; W. Schlesinger and R. Oren.

    2005-01-01

    Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C uptake by the biosphere increases in response to the fossil-fuel driven increase in atmospheric [CO2] ("CO2 fertilization...

  13. Geological storage of CO2

    International Nuclear Information System (INIS)

    Czernichowski-Lauriol, I.

    2005-01-01

    The industrial storage of CO 2 is comprised of three steps: - capture of CO 2 where it is produced (power plants, cement plants, etc.); - transport (pipe lines or boats); - storage, mainly underground, called geological sequestration... Three types of reservoirs are considered: - salted deep aquifers - they offer the biggest storage capacity; - exhausted oil and gas fields; - non-exploited deep coal mine streams. The two latter storage types may allow the recovery of sellable products, which partially or totally offsets the storage costs. This process is largely used in the petroleum industry to improve the productivity of an oil field, and is called FOR (Enhanced Oil Recovery). A similar process is applied in the coal mining industry to recover the imprisoned gas, and is called ECBM (Enhanced Coal Bed methane). Two storage operations have been initiated in Norway and in Canada, as well as research programmes in Europe, North America, Australia and Japan. International organisations to stimulate this technology have been created such as the 'Carbon Sequestration Leadership Forum' and 'the Intergovernmental Group for Climate Change'. This technology will be taken into account in the instruments provided by the Tokyo Protocol. (author)

  14. CO2 Abatement In The Iron And Steel Industry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-01-15

    The iron and steel industry is the largest industrial source of CO2 emissions due to the energy intensity of steel production, its reliance on carbon-based fuels and reductants, and the large volume of steel produced -- over 1414 Mt in 2010. With the growing concern over climate change, steel makers are faced with the challenge of finding ways of lowering CO2 emissions without seriously undermining process efficiency or considerably adding to costs. This report examines ways of abating CO2 emissions from raw materials preparation (coking, sintering and pelletising plants) through to the production of liquid steel in basic oxygen furnaces and electric arc furnaces. Direct reduction and smelting reduction processes are covered, as well as iron making in a blast furnace. A range of technologies and measures exist for lowering CO2 emissions including minimising energy consumption and improving energy efficiency, changing to a fuel and/or reducing agent with a lower CO2 emission factor (such as wood charcoal), and capturing the CO2 and storing it underground. Significant CO2 reductions can be achieved by combining a number of the available technologies. If carbon capture and storage is fitted than steel plants could become near zero emitters of CO2.

  15. Mesoscale modelling of atmospheric CO2 across Denmark

    DEFF Research Database (Denmark)

    Lansø, Anne Sofie

    2016-01-01

    of the simulated atmospheric CO2 across Denmark was, in particular, affected by the Danish terrestrial surface exchanges and its temporal variability. This study urges all future modelling studies of air–sea CO2 to include short-term variability in pCO2. To capture the full heterogeneity of the surface exchanges......It is scientifically well-established that the increase of atmospheric CO2 affects the entire globe and will lead to higher surface temperatures. Although anthropogenic CO2is emitted straight into the atmosphere, it does not all contribute to the existing atmospheric CO2 reservoir. Approximately 29......% is taken up by the global oceans, due to under-saturation of CO2 in the surface waters, while another 33 % is taken up by the terrestrial biosphere, via photosynthesis. In order to estimate the effects of increasing anthropogenic emissions of CO2 more accurately in the future, it is essential to understand...

  16. CO2 leakage monitoring and analysis to understand the variation of CO2 concentration in vadose zone by natural effects

    Science.gov (United States)

    Joun, Won-Tak; Ha, Seung-Wook; Kim, Hyun Jung; Ju, YeoJin; Lee, Sung-Sun; Lee, Kang-Kun

    2017-04-01

    Controlled ex-situ experiments and continuous CO2 monitoring in the field are significant implications for detecting and monitoring potential leakage from CO2 sequestration reservoir. However, it is difficult to understand the observed parameters because the natural disturbance will fluctuate the signal of detections in given local system. To identify the original source leaking from sequestration reservoir and to distinguish the camouflaged signal of CO2 concentration, the artificial leakage test was conducted in shallow groundwater environment and long-term monitoring have been performed. The monitoring system included several parameters such as pH, temperature, groundwater level, CO2 gas concentration, wind speed and direction, atmospheric pressure, borehole pressure, and rainfall event etc. Especially in this study, focused on understanding a relationship among the CO2 concentration, wind speed, rainfall and pressure difference. The results represent that changes of CO2 concentration in vadose zone could be influenced by physical parameters and this reason is helpful in identifying the camouflaged signal of CO2 concentrations. The 1-D column laboratory experiment also was conducted to understand the sparking-peak as shown in observed data plot. The results showed a similar peak plot and could consider two assumptions why the sparking-peak was shown. First, the trapped CO2 gas was escaped when the water table was changed. Second, the pressure equivalence between CO2 gas and water was broken when the water table was changed. These field data analysis and laboratory experiment need to advance due to comprehensively quantify local long-term dynamics of the artificial CO2 leaking aquifer. Acknowledgement Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003)

  17. Reconciling apparent inconsistencies in estimates of terrestrial CO2 sources and sinks

    International Nuclear Information System (INIS)

    House, J.I.; Prentice, I.C.; Heimann, M.; Ramankutty, N.

    2003-01-01

    The magnitude and location of terrestrial carbon sources and sinks remains subject to large uncertainties. Estimates of terrestrial CO 2 fluxes from ground-based inventory measurements typically find less carbon uptake than inverse model calculations based on atmospheric CO 2 measurements, while a wide range of results have been obtained using models of different types. However, when full account is taken of the processes, pools, time scales and geographic areas being measured, the different approaches can be understood as complementary rather than inconsistent, and can provide insight as to the contribution of various processes to the terrestrial carbon budget. For example, quantitative differences between atmospheric inversion model estimates and forest inventory estimates in northern extratropical regions suggest that carbon fluxes to soils (often not accounted for in inventories), and into non-forest vegetation, may account for about half of the terrestrial uptake. A consensus of inventory and inverse methods indicates that, in the 1980s, northern extratropical land regions were a large net sink of carbon, and the tropics were approximately neutral (albeit with high uncertainty around the central estimate of zero net flux). The terrestrial flux in southern extratropical regions was small. Book-keeping model studies of the impacts of land-use change indicated a large source in the tropics and almost zero net flux for most northern extratropical regions; similar land use change impacts were also recently obtained using process-based models. The difference between book-keeping land-use change model studies and inversions or inventories was previously interpreted as a 'missing' terrestrial carbon uptake. Land-use change studies do not account for environmental or many management effects (which are implicitly included in inventory and inversion methods). Process-based model studies have quantified the impacts of CO 2 fertilisation and climate change in addition to

  18. Interface characteristics in Co2MnSi/Ag/Co2MnSi trilayer

    International Nuclear Information System (INIS)

    Li, Yang; Chen, Hong; Wang, Guangzhao; Yuan, Hongkuan

    2016-01-01

    Highlights: • Inferface DO 3 disorder is most favorable in Co 2 MnSi/Ag/Co 2 MnSi trilayer. • Interface itself and inferface DO 3 disorder destroy the half-metallicity of interface layers. • Magnetoresistance is reduced by the interface itself and interface disorder. • Magnetotransport coefficient is largely reduced by the interface itself and interface disorder. - Abstract: Interface characteristics of Co 2 MnSi/Ag/Co 2 MnSi trilayer have been investigated by means of first-principles. The most likely interface is formed by connecting MnSi-termination to the bridge site between two Ag atoms. As annealed at high temperature, the formation of interface DO 3 disorder is most energetically favorable. The spin polarization is reduced by both the interface itself and interface disorder due to the interface state occurs in the minority-spin gap. As a result, the magneto-resistance ratio has a sharp drop based on the estimation of a simplified modeling.

  19. Alberta industrial synergy CO2 programs initiative

    International Nuclear Information System (INIS)

    Yildirim, E.

    1998-01-01

    The various industrial sectors within Alberta produce about 350,000 tonnes of CO 2 per day. This presentation was concerned with how this large volume and high concentration of CO 2 can be used in industrial and agricultural applications, because every tonne of CO 2 used for such purposes is a tonne that does not end up in the atmosphere. There is a good potential for an industrial synergy between the producers and users of CO 2 . The Alberta Industrial Synergy CO 2 Programs Initiative was established to ultimately achieve a balance between the producers of CO 2 and the users of CO 2 by creating ways to use the massive quantities of CO 2 produced by Alberta's hydrocarbon-based economy. The Alberta CO 2 Research Steering Committee was created to initiate and support CO 2 programs such as: (1) CO 2 use in enhanced oil recovery, (2) creation of a CO 2 production inventory, (3) survey of CO 2 users and potential users, (4) investigation of process issues such as power generation, oil sands and cement manufacturing, and (5) biofixation by plants, (6) other disposal options (e.g. in depleted oil and gas reservoirs, in aquifers, in tailings ponds, in coal beds). The single most important challenge was identified as 'rationalizing the formation of the necessary infrastructure'. Failing to do that will greatly impede efforts directed towards CO 2 utilization

  20. Renewable energy and CO_2 abatement in Italy

    International Nuclear Information System (INIS)

    Marcantonini, Claudio; Valero, Vanessa

    2017-01-01

    In order to combat global warming, Italy has committed to reduce its CO_2 emissions. To this end, it has significantly encouraged renewable energy development through a variety of support schemes, ranging from green certificates to feed-in and premium tariffs. As a result, the production of electricity from renewable energy sources, in particular from solar and wind energy, has risen considerably over the past years. In this paper we review the Italian support schemes for wind and solar energy and estimate the cost of abating CO_2 emissions by generating electricity from these two sources of energy for the period 2008–2011. The results show that the average costs for wind were around 165 €/tCO_2. For solar, they were much higher, around 1000 €/tCO_2, as solar energy received much higher remunerations than wind energy. These costs were much higher than in Germany. This was due to the differences between the level of incentives and the different power systems. - Highlights: • We estimate the cost of reducing CO_2 emissions by wind and solar energy in Italy in 2008–2011. • The average costs for wind were around 165 €/tCO_2. • The average costs for solar were much higher, around 1000 €/tCO_2. • Those costs were much higher than in Germany. • This was due to the differences in the levels of incentives and to the different power systems.

  1. Modelling the diurnal and seasonal dynamics of soil CO2 exchange in a semiarid ecosystem with high plant–interspace heterogeneity

    Directory of Open Access Journals (Sweden)

    J. Gong

    2018-01-01

    Full Text Available We used process-based modelling to investigate the roles of carbon-flux (C-flux components and plant–interspace heterogeneities in regulating soil CO2 exchanges (FS in a dryland ecosystem with sparse vegetation. To simulate the diurnal and seasonal dynamics of FS, the modelling considered simultaneously the CO2 production, transport and surface exchanges (e.g. biocrust photosynthesis, respiration and photodegradation. The model was parameterized and validated with multivariate data measured during the years 2013–2014 in a semiarid shrubland ecosystem in Yanchi, northwestern China. The model simulation showed that soil rewetting could enhance CO2 dissolution and delay the emission of CO2 produced from rooting zone. In addition, an ineligible fraction of respired CO2 might be removed from soil volumes under respiration chambers by lateral water flows and root uptakes. During rewetting, the lichen-crusted soil could shift temporally from net CO2 source to sink due to the activated photosynthesis of biocrust but the restricted CO2 emissions from subsoil. The presence of plant cover could decrease the root-zone CO2 production and biocrust C sequestration but increase the temperature sensitivities of these fluxes. On the other hand, the sensitivities of root-zone emissions to water content were lower under canopy, which may be due to the advection of water flows from the interspace to canopy. To conclude, the complexity and plant–interspace heterogeneities of soil C processes should be carefully considered to extrapolate findings from chamber to ecosystem scales and to predict the ecosystem responses to climate change and extreme climatic events. Our model can serve as a useful tool to simulate the soil CO2 efflux dynamics in dryland ecosystems.

  2. Modelling the diurnal and seasonal dynamics of soil CO2 exchange in a semiarid ecosystem with high plant-interspace heterogeneity

    Science.gov (United States)

    Gong, Jinnan; Wang, Ben; Jia, Xin; Feng, Wei; Zha, Tianshan; Kellomäki, Seppo; Peltola, Heli

    2018-01-01

    We used process-based modelling to investigate the roles of carbon-flux (C-flux) components and plant-interspace heterogeneities in regulating soil CO2 exchanges (FS) in a dryland ecosystem with sparse vegetation. To simulate the diurnal and seasonal dynamics of FS, the modelling considered simultaneously the CO2 production, transport and surface exchanges (e.g. biocrust photosynthesis, respiration and photodegradation). The model was parameterized and validated with multivariate data measured during the years 2013-2014 in a semiarid shrubland ecosystem in Yanchi, northwestern China. The model simulation showed that soil rewetting could enhance CO2 dissolution and delay the emission of CO2 produced from rooting zone. In addition, an ineligible fraction of respired CO2 might be removed from soil volumes under respiration chambers by lateral water flows and root uptakes. During rewetting, the lichen-crusted soil could shift temporally from net CO2 source to sink due to the activated photosynthesis of biocrust but the restricted CO2 emissions from subsoil. The presence of plant cover could decrease the root-zone CO2 production and biocrust C sequestration but increase the temperature sensitivities of these fluxes. On the other hand, the sensitivities of root-zone emissions to water content were lower under canopy, which may be due to the advection of water flows from the interspace to canopy. To conclude, the complexity and plant-interspace heterogeneities of soil C processes should be carefully considered to extrapolate findings from chamber to ecosystem scales and to predict the ecosystem responses to climate change and extreme climatic events. Our model can serve as a useful tool to simulate the soil CO2 efflux dynamics in dryland ecosystems.

  3. Sea ice contribution to the air-sea CO(2) exchange in the Arctic and Southern Oceans

    DEFF Research Database (Denmark)

    Rysgaard...[], Søren; Bendtsen, Jørgen; Delille, B.

    2011-01-01

    Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO(2) and the subsequent effect on air-sea CO(2) exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air......-sea CO(2) exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO(2) uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO(2) uptake in ice-free polar seas. This sea......-sea CO(2) exchange during winter, and (3) release of CO(2)-depleted melt water with excess total alkalinity during sea-ice decay and (4) biological CO(2) drawdown during primary production in sea ice and surface oceanic waters....

  4. CO2 maximum in the oxygen minimum zone (OMZ)

    OpenAIRE

    Paulmier, Aurélien; Ruiz-Pino, D.; Garcon, V.

    2011-01-01

    International audience; Oxygen minimum zones (OMZs), known as suboxic layers which are mainly localized in the Eastern Boundary Upwelling Systems, have been expanding since the 20th "high CO2" century, probably due to global warming. OMZs are also known to significantly contribute to the oceanic production of N2O, a greenhouse gas (GHG) more efficient than CO2. However, the contribution of the OMZs on the oceanic sources and sinks budget of CO2, the main GHG, still remains to be established. ...

  5. CO2 Effects in Space: Relationship to Intracranial Hypertension

    Science.gov (United States)

    Alexander, David J.

    2011-01-01

    This slide presentation reviews the effects of enhanced exposure to CO2 on Earth and in space. The effects of enhanced exposure to CO2 are experienced in almost all bodily systems. In space some of the effects are heightened due to the fluid shifts to the thorax and head. This fluid shift results in increased intracranial pressure, congested cerebral circulation, increased Cerebral Blood Flow (CBF) and Intravenous dilatation. The mechanism of the effect of CO2 on CBF is diagrammed, as is the Cerebrospinal Fluid (CSF) production. A listing of Neuroendocrine targets is included.

  6. Temporal and spatial variations in on-road energy use and CO2 emissions in China, 1978–2008

    International Nuclear Information System (INIS)

    Liu, Yang; Wang, Yu; Huo, Hong

    2013-01-01

    China is experiencing rapid motorization and each city has a unique motorization pathway owing to its different characteristics and development progress. The temporal and spatial variation trend in on-road energy use and CO 2 emissions need to be better understood in order to project the future growth and to support policy-making at both local and national levels. This study simulates the on-road energy use and CO 2 emissions of all of China's prefectural-level cities (and above) from 1978 through 2008, on the basis of the collected vehicle data from hundreds of national and local statistical yearbooks. The results show that China's on-road energy use and CO 2 emissions were 119 million metric tons (MMT) and 377 MMT in 2008, respectively—20 times the levels in 1978. The economically developed cities and heavy industrial cities had the highest on-road energy use and CO 2 emissions before the year 2000, but recently the spatial distribution has varied significantly as the uptake of motorization increases successively in these cities. Now and in the near future, the most important driving force of the on-road energy and CO 2 growth in China is the great number of average cities that have just started or will soon start the motorization. - Highlights: • China's cities have unique motorization pathways due to their unique characteristics. • We simulate on-road energy use and CO 2 emissions of all cities in China in 1978–2008. • China's on-road energy use and CO 2 emissions in 2008 were 20 times the levels in 1978. • Large cities had the highest on-road energy usage but the growth rate is declining. • Non-large cities are the main impetus of the growth in China's on-road energy use

  7. Achieving Negative CO2 Emissions by Protecting Ocean Chemistry

    Science.gov (United States)

    Cannara, A.

    2016-12-01

    Industrial Age CO2 added 1.8 trillion tons to the atmosphere. About ¼ has dissolved in seas. The rest still dissolves, bolstered by present emissions of >30 gigatons/year. Airborne & oceanic CO2 have induced sea warming & ocean acidification*. This paper suggests a way to induce a negative CO2-emissions environment for climate & oceans - preserve the planet`s dominant CO2-sequestration system ( 1 gigaton/year via calcifying sea life**) by promptly protecting ocean chemistry via expansion of clean power for both lime production & replacement of CO2-emitting sources. Provide natural alkali (CaO, MgO…) to oceans to maintain average pH above 8.0, as indicated by marine biologists. That alkali (lime) is available from past calcifying life's limestone deposits, so can be returned safely to seas once its CO2 is removed & permanently sequestered (Carbfix, BSCP, etc.***). Limestone is a dense source of CO2 - efficient processing per mole sequestered. Distribution of enough lime is possible via cargo-ship transits - 10,000 tons lime/transit, 1 million transits/year. New Panamax ships carry 120,000 tons. Just 10,000/transit allows gradual reduction of present & past CO2 emissions effects, if coupled with combustion-power reductions. CO2 separation from limestone, as in cement plants, consumes 400kWHrs of thermal energy per ton of output lime (or CO2). To combat yearly CO2 dissolution in seas, we must produce & distribute about 10gigatons of lime/year. Only nuclear power produces the clean energy (thousands of terawatt hours) to meet this need - 1000 dedicated 1GWe reactors, processing 12 cubic miles of limestone/year & sequestering CO2 into a similar mass of basalt. Basalt is common in the world. Researchers*** report it provides good, mineralized CO2 sequestration. The numbers above allow gradual CO2 reduction in air and seas, if we return to President Kennedy's energy path: http://tinyurl.com/6xgpkfa We're on an environmental precipice due to failure to eliminate

  8. CO2 on the International Space Station: An Operations Update

    Science.gov (United States)

    Law, Jennifer; Alexander, David

    2016-01-01

    PROBLEM STATEMENT: We describe CO2 symptoms that have been reported recently by crewmembers on the International Space Station and our continuing efforts to control CO2 to lower levels than historically accepted. BACKGROUND: Throughout the International Space Station (ISS) program, anecdotal reports have suggested that crewmembers develop CO2-related symptoms at lower CO2 levels than would be expected terrestrially. Since 2010, operational limits have controlled the 24-hour average CO2 to 4.0 mm Hg, or below as driven by crew symptomatology. In recent years, largely due to increasing awareness by crew and ground team, there have been increased reports of crew symptoms. The aim of this presentation is to discuss recent observations and operational impacts to lower CO2 levels on the ISS. CASE PRESENTATION: Crewmembers are routinely asked about CO2 symptoms in their weekly private medical conferences with their crew surgeons. In recent ISS expeditions, crewmembers have noted symptoms attributable to CO2 starting at 2.3 mmHg. Between 2.3 - 2.7 mm Hg, fatigue and full-headedness have been reported. Between 2.7 - 3.0 mm Hg, there have been self-reports of procedure missed steps or procedures going long. Above 3.0 - 3.4 mm Hg, headaches have been reported. A wide range of inter- and intra-individual variability in sensitivity to CO2 have been noted. OPERATIONAL / CLINICAL RELEVANCE: These preliminary data provide semi-quantitative ranges that have been used to inform a new operational limit of 3.0 mmHg as a compromise between systems capabilities and the recognition that there are human health and performance impacts at recent ISS CO2 levels. Current evidence would suggest that an operational limit between 0.5 and 2.0 mm Hg may maintain health and performance. Future work is needed to establish long-term ISS and future vehicle operational limits.

  9. Hurricane Arthur and its effect on the short-term variability of pCO2 on the Scotian Shelf, NW Atlantic

    Science.gov (United States)

    Lemay, Jonathan; Thomas, Helmuth; Craig, Susanne E.; Burt, William J.; Fennel, Katja; Greenan, Blair J. W.

    2018-04-01

    The understanding of the seasonal variability of carbon cycling on the Scotian Shelf in the NW Atlantic Ocean has improved in recent years; however, very little information is available regarding its short-term variability. In order to shed light on this aspect of carbon cycling on the Scotian Shelf we investigate the effects of Hurricane Arthur, which passed the region on 5 July 2014. The hurricane caused a substantial decline in the surface water partial pressure of CO2 (pCO2), even though the Scotian Shelf possesses CO2-rich deep waters. High-temporal-resolution data of moored autonomous instruments demonstrate that there is a distinct layer of relatively cold water with low dissolved inorganic carbon (DIC) slightly above the thermocline, presumably due to a sustained population of phytoplankton. Strong storm-related wind mixing caused this cold intermediate layer with high phytoplankton biomass to be entrained into the surface mixed layer. At the surface, phytoplankton begin to grow more rapidly due to increased light. The combination of growth and the mixing of low DIC water led to a short-term reduction in the partial pressure of CO2 until wind speeds relaxed and allowed for the restratification of the upper water column. These hurricane-related processes caused a (net) CO2 uptake by the Scotian Shelf region that is comparable to the spring bloom, thus exerting a major impact on the annual CO2 flux budget.

  10. Towards CO2 sequestration and applications of CO2 hydrates: the effects of tetrahydrofuran on the phase equilibria of CO2 hydrates

    International Nuclear Information System (INIS)

    Khalik, M.S.; Peters, C.J.

    2006-01-01

    The increasing quantity of carbon dioxide (CO 2 ) in the atmosphere has caused widespread global concerns. Capturing CO 2 from its sources and stored it in the form of gas hydrates and application of CO 2 hydrates are among the proposed methods to overcome this problem. In order to make hydrate-based process more attractive, the use of cyclic ethers as promoters is suggested to reduce the required hydrate formation pressure and enhancing the corresponding kinetic rate. In the present work, tetrahydrofuran (THF) is chosen as a hydrate promoter, participating in forming hydrates and produces mixed hydrate together with CO 2 . The pressure and temperature ranges of hydrate stability region are carefully determined through phase equilibrium measurement of the ternary CO 2 , tetrahydrofuran (THF) and water systems. From the experimental results, it is confirmed that the presence of THF in CO 2 + water systems will extend the hydrate formation region to higher temperature at a constant pressure. The extension of the hydrate stability region is depended on the overall concentration of the ternary system. Moreover, four-phase equilibrium of H-Lw-Lv-V is observed in the system, which may be due to a liquid phase split. In the region where the four-phase equilibrium exists, the ternary system loses its concentration dependency of the hydrate equilibrium conditions. (Author)

  11. Porous materials as high performance adsorbents for CO2 capture, gas separation and purification

    Science.gov (United States)

    Wang, Jun

    Global warming resulted from greenhouse gases emission has received a widespread attention. Among the greenhouse gases, CO2 contributes more than 60% to global warming due to its huge emission amount. The flue gas contains about 15% CO2 with N2 as the balance. If CO2 can be separated from flue gas, the benefit is not only reducing the global warming effect, but also producing pure CO2 as a very useful industry raw material. Substantial progress is urgent to be achieved in an industrial process. Moreover, energy crisis is one of the biggest challenges for all countries due to the short life of fossil fuels, such as, petroleum will run out in 50 years and coal will run out in 150 years according to today's speed. Moreover, the severe pollution to the environment caused by burning fossil fuels requires us to explore sustainable, environment-friendly, and facile energy sources. Among several alternative energy sources, natural gas is one of the most promising alternative energy sources due to its huge productivity, abundant feed stock, and ease of generation. In order to realize a substantial adsorption process in industry, synthesis of new adsorbents or modification of existing adsorbent with improved properties has become the most critical issue. This dissertation reports systemic characterization and development of five serials of novel adsorbents with advanced adsorption properties. In chapter 2, nitrogen-doped Hypercross-linking Polymers (HCPs) have been synthesized successfully with non-carcinogenic chloromethyl methyl ether (CME) as the cross-linking agent within a single step. Texture properties, surface morphology, CO2/N2 selectivity, and adsorption heat have been presented and demonstrated properly. A comprehensive discussion on factors that affect the CO2 adsorption and CO2/N 2 separation has also been presented. It was found that high micropore proportion and N-content could effectively enhance CO2 uptake and CO2/N2 separation selectivity. In chapter 3, a

  12. ISLSCP II Globalview: Atmospheric CO2 Concentrations

    Data.gov (United States)

    National Aeronautics and Space Administration — The GlobalView Carbon Dioxide (CO2) data product contains synchronized and smoothed time series of atmospheric CO2 concentrations at selected sites that were created...

  13. Decontamination of solid matrices using supercritical CO2: study of contaminant-additives-CO2

    International Nuclear Information System (INIS)

    Galy, J.

    2006-11-01

    the CO 2 and the evolution of the sedimentation time in terms of the surfactant concentration. A stabilization of the sedimentation time appears in the case of PE 8100, which is not the case for PE 6100. Moreover, the concentration of the appearance of the stabilization is near the ISC. Nevertheless, PE 6100 spreads and stabilizes better and longer a solid suspension of CeO 2 , due to a better solvation of the 'CO 2 -phily' chains. In conclusion, these results on model surfactants have allowed to perceive the behaviours of hydrocarbonaceous surfactants in the supercritical CO 2 , in validating the use of such compounds in an apolar and dense medium and to implement different tools of anticipation and classification. (O.M.)

  14. Increased cellular uptake of lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles due to surface modification with folic acid.

    Science.gov (United States)

    Feuser, Paulo Emilio; Arévalo, Juan Marcelo Carpio; Junior, Enio Lima; Rossi, Gustavo Rodrigues; da Silva Trindade, Edvaldo; Rocha, Maria Eliane Merlin; Jacques, Amanda Virtuoso; Ricci-Júnior, Eduardo; Santos-Silva, Maria Claudia; Sayer, Claudia; de Araújo, Pedro H Hermes

    2016-12-01

    Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles surface modified with folic acid were synthesized by miniemulsion polymerization in just one step. In vitro biocompatibility and cytotoxicity assays on L929 (murine fibroblast), human red blood, and HeLa (uterine colon cancer) cells were performed. The effect of folic acid at the nanoparticles surface was evaluated through cellular uptake assays in HeLa cells. Results showed that the presence of folic acid did not affect substantially the polymer particle size (~120 nm), the superparamagnetic behavior, the encapsulation efficiency of lauryl gallate (~87 %), the Zeta potential (~38 mV) of the polymeric nanoparticles or the release profile of lauryl gallate. The release profile of lauryl gallate from superparamagnetic poly(methyl methacrylate) nanoparticles presented an initial burst effect (0-1 h) followed by a slow and sustained release, indicating a biphasic release system. Lauryl gallate loaded in superparamagnetic poly(methyl methacrylate) nanoparticles with folic acid did not present cytotoxicity effects on L929 and human red blood cells. However, free lauryl gallate presented significant cytotoxic effects on L929 and human red blood cells at all tested concentrations. The presence of folic acid increased the cytotoxicity of lauryl gallate loaded in nanoparticles on HeLa cells due to a higher cellular uptake when HeLa cells were incubated at 37 °C. On the other hand, when the nanoparticles were incubated at low temperature (4 °C) cellular uptake was not observed, suggesting that the uptake occurred by folate receptor mediated energy-dependent endocytosis. Based on presented results our work suggests that this carrier system can be an excellent alternative in targeted drug delivery by folate receptor.

  15. North America's net terrestrial CO2 exchange with the atmosphere 1990-2009

    Science.gov (United States)

    King, A. W.; Andres, R. J.; Davis, K. J.; Hafer, M.; Hayes, D. J.; Huntzinger, D. N.; de Jong, B.; Kurz, W. A.; McGuire, A. D.; Vargas, R.; Wei, Y.; West, T. O.; Woodall, C. W.

    2015-01-01

    Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO2 emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land-atmosphere CO2 exchange for North America (Canada, United States, and Mexico) over the period 1990-2009. Only CO2 is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO2, with a net transfer from atmosphere to land. Estimates ranged from -890 to -280 Tg C yr-1, where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, "best" estimates (i.e., measures of central tendency) are -472 ± 281 Tg C yr-1 based on the mean and standard deviation of the distribution and -360 Tg C yr-1 (with an interquartile range of -496 to -337) based on the median. Considering both the fossil fuel emissions source and the land sink, our analysis shows that North America was, however, a net contributor to the growth of CO2 in the atmosphere in the late 20th and early 21st century. With North America's mean annual fossil fuel CO2 emissions for the period 1990-2009 equal to 1720 Tg C yr-1 and assuming the estimate of -472 Tg C yr-1 as an approximation of the true terrestrial CO2 sink, the continent's source : sink ratio for this time period was 1720:472, or nearly 4:1.

  16. North America's net terrestrial CO2 exchange with the atmosphere 1990–2009

    Science.gov (United States)

    King, A.W.; Andres, R.J.; Davis, K.J.; Hafer, M.; Hayes, D.J.; Huntzinger, Deborah N.; de Jong, Bernardus; Kurz, W.A.; McGuire, A. David; Vargas, Rodrigo I.; Wei, Y.; West, Tristram O.; Woodall, Christopher W.

    2015-01-01

    Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO2 emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land–atmosphere CO2 exchange for North America (Canada, United States, and Mexico) over the period 1990–2009. Only CO2 is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO2, with a net transfer from atmosphere to land. Estimates ranged from −890 to −280 Tg C yr−1, where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, "best" estimates (i.e., measures of central tendency) are −472 ± 281 Tg C yr−1 based on the mean and standard deviation of the distribution and −360 Tg C yr−1 (with an interquartile range of −496 to −337) based on the median. Considering both the fossil fuel emissions source and the land sink, our analysis shows that North America was, however, a net contributor to the growth of CO2 in the atmosphere in the late 20th and early 21st century. With North America's mean annual fossil fuel CO2 emissions for the period 1990–2009 equal to 1720 Tg C yr−1 and assuming the estimate of −472 Tg C yr−1 as an approximation of the true terrestrial CO2 sink, the continent's source : sink ratio for this time period was

  17. Bioelectrochemical conversion of CO2 to chemicals

    NARCIS (Netherlands)

    Bajracharya, Suman; Vanbroekhoven, Karolien; Buisman, Cees J.N.; Strik, David P.B.T.B.; Pant, Deepak

    2017-01-01

    The recent concept of microbial electrosynthesis (MES) has evolved as an electricity-driven production technology for chemicals from low-value carbon dioxide (CO2) using micro-organisms as biocatalysts. MES from CO2 comprises bioelectrochemical reduction of CO2 to multi-carbon organic compounds

  18. Implicit CO_2 prices of fossil fuel use in Switzerland

    International Nuclear Information System (INIS)

    Schleiniger, Reto

    2016-01-01

    This study aims to assess the efficiency of the fossil fuel taxation scheme currently in effect in Switzerland. To this end, the concept of implicit CO_2 prices is introduced, based on which prices for different fossil fuel uses are derived. Implicit CO_2 prices are defined as the difference between actual prices paid by consumers and efficient domestic fuel prices. Efficient domestic fuel prices, in turn, consist of private production costs, a uniform value added tax and only local external costs, not including external costs due to CO_2 emissions and global climate change. The resulting prices differ substantially, which suggests that there is considerable cost-saving potential in reducing CO_2 emissions in Switzerland. For passenger cars and air traffic, the implicit prices are negative. For these uses, higher fuel charges would therefore be beneficial from a purely domestic perspective, i.e., without considering the negative repercussions of global warming. - Highlights: •Efficient fossil fuel policy must take into account local and global externalities. •Implicit CO_2 prices are applied as efficiency indicator of fossil energy policy. •Implicit CO_2 prices vary strongly for different fossil fuel uses in Switzerland. •There is a large cost-saving potential in terms of reducing CO_2 emissions.

  19. Neutron diffraction study of the inverse spinels Co2TiO4 and Co2SnO4

    Science.gov (United States)

    Thota, S.; Reehuis, M.; Maljuk, A.; Hoser, A.; Hoffmann, J.-U.; Weise, B.; Waske, A.; Krautz, M.; Joshi, D. C.; Nayak, S.; Ghosh, S.; Suresh, P.; Dasari, K.; Wurmehl, S.; Prokhnenko, O.; Büchner, B.

    2017-10-01

    We report a detailed single-crystal and powder neutron diffraction study of Co2TiO4 and Co2SnO4 between the temperature 1.6 and 80 K to probe the spin structure in the ground state. For both compounds the strongest magnetic intensity was observed for the (111)M reflection due to ferrimagnetic ordering, which sets in below TN=48.6 and 41 K for Co2TiO4 and Co2SnO4 , respectively. An additional low intensity magnetic reflection (200)M was noticed in Co2TiO4 due to the presence of an additional weak antiferromagnetic component. Interestingly, from both the powder and single-crystal neutron data of Co2TiO4 , we noticed a significant broadening of the magnetic (111)M reflection, which possibly results from the disordered character of the Ti and Co atoms on the B site. Practically, the same peak broadening was found for the neutron powder data of Co2SnO4 . On the other hand, from our single-crystal neutron diffraction data of Co2TiO4 , we found a spontaneous increase of particular nuclear Bragg reflections below the magnetic ordering temperature. Our data analysis showed that this unusual effect can be ascribed to the presence of anisotropic extinction, which is associated to a change of the mosaicity of the crystal. In this case, it can be expected that competing Jahn-Teller effects acting along different crystallographic axes can induce anisotropic local strain. In fact, for both ions Ti3 + and Co3 +, the 2 tg levels split into a lower dx y level yielding a higher twofold degenerate dx z/dy z level. As a consequence, one can expect a tetragonal distortion in Co2TiO4 with c /a <1 , which we could not significantly detect in the present work.

  20. Effect of Mineral Dissolution/Precipitation and CO2 Exsolution on CO2 transport in Geological Carbon Storage.

    Science.gov (United States)

    Xu, Ruina; Li, Rong; Ma, Jin; He, Di; Jiang, Peixue

    2017-09-19

    continuously injected through the core. The MRI results indicate dissolution of the carbonates during the experiments since the porosity has been increased after the core-flooding experiments. The mineral dissolution changes the pore structure by enlarging the throat diameters and decreasing the pore specific surface areas, resulting in lower CO 2 /water capillary pressures and changes in the relative permeability. When the reservoir pressure decreases, the CO 2 exsolution occurs due to the reduction of solubility. The CO 2 bubbles preferentially grow toward the larger pores instead of toward the throats or the finer pores during the depressurization. After exsolution, the exsolved CO 2 phase shows low mobility due to the highly dispersed pore-scale morphology, and the well dispersed small bubbles tend to merge without interface contact driven by the Ostwald ripening mechanism. During depressurization, the dissolved carbonate could also precipitate as a result of increasing pH. There is increasing formation water flow resistance and low mobility of the CO 2 in the presence of CO 2 exsolution and carbonate precipitation. These effects produce a self-sealing mechanism that may reduce unfavorable CO 2 migration even in the presence of sudden reservoir depressurization.

  1. Mechanisms of carbon dioxide acquisition and CO2 sensing in marine diatoms: a gateway to carbon metabolism.

    Science.gov (United States)

    Matsuda, Yusuke; Hopkinson, Brian M; Nakajima, Kensuke; Dupont, Christopher L; Tsuji, Yoshinori

    2017-09-05

    Diatoms are one of the most successful marine eukaryotic algal groups, responsible for up to 20% of the annual global CO 2 fixation. The evolution of a CO 2 -concentrating mechanism (CCM) allowed diatoms to overcome a number of serious constraints on photosynthesis in the marine environment, particularly low [CO 2 ] aq in seawater relative to concentrations required by the CO 2 fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), which is partly due to the slow diffusion rate of CO 2 in water and a limited CO 2 formation rate from [Formula: see text] in seawater. Diatoms use two alternative strategies to take up dissolved inorganic carbon (DIC) from the environment: one primarily relies on the direct uptake of [Formula: see text] through plasma-membrane type solute carrier (SLC) 4 family [Formula: see text] transporters and the other is more reliant on passive diffusion of CO 2 formed by an external carbonic anhydrase (CA). Bicarbonate taken up into the cytoplasm is most likely then actively transported into the chloroplast stroma by SLC4-type transporters on the chloroplast membrane system. Bicarbonate in the stroma is converted into CO 2 only in close proximity to RubisCO preventing unnecessary CO 2 leakage. CAs play significant roles in mobilizing DIC as it is progressively moved towards the site of fixation. However, the evolutionary types and subcellular locations of CAs are not conserved between different diatoms, strongly suggesting that this DIC mobilization strategy likely evolved multiple times with different origins. By contrast, the recent discovery of the thylakoid luminal θ-CA indicates that the strategy to supply CO 2 to RubisCO in the pyrenoid may be very similar to that of green algae, and strongly suggests convergent coevolution in CCM function of the thylakoid lumen not only among diatoms but among eukaryotic algae in general. In this review, both experimental and corresponding theoretical models of the diatom CCMs are

  2. On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

    OpenAIRE

    Couldrey, Matthew; Oliver, Kevin; Yool, Andrew; Halloran, Paul; Achterberg, Eric

    2016-01-01

    The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual...

  3. CO2 reduction through energy conservation

    International Nuclear Information System (INIS)

    1991-05-01

    A study was carried out of the potential to economically reduce carbon dioxide emissions through energy conservation in the petroleum and natural gas industry. The study examined current and projected emissions levels, cogeneration at gas plants, flaring, economics, regulation, reporting requirements, implementation, and research and development. Economically attractive energy conservation measures can reduce oil and gas industry, exclusive of Athabasca oil sands operations, CO 2 emissions by 6-7%. The energy conservation options identified range from field energy awareness committees through to equipment retrofits and replacement. At ca 3 million tonnes/y, these reductions will not offset the increases in oil and gas related CO 2 emissions anticipated by producers and Alberta government agencies. There will be increasing emphasis on in-situ bitumen production, more energy intensive light crude oil production and increasing natural gas sales, increasing energy inputs in excess of reductions. Cogeneration of electricity for utility company distribution and for internally required steam at gas plants and in-situ production sites is not economic due to low electricity prices. 8 tabs

  4. Design of experimental setup for supercritical CO2 jet under high ambient pressure conditions

    Science.gov (United States)

    Shi, Huaizhong; Li, Gensheng; He, Zhenguo; Wang, Haizhu; Zhang, Shikun

    2016-12-01

    With the commercial extraction of hydrocarbons in shale and tight reservoirs, efficient methods are needed to accelerate developing process. Supercritical CO2 (SC-CO2) jet has been considered as a potential way due to its unique fluid properties. In this article, a new setup is designed for laboratory experiment to research the SC-CO2 jet's characteristics in different jet temperatures, pressures, standoff distances, ambient pressures, etc. The setup is composed of five modules, including SC-CO2 generation system, pure SC-CO2 jet system, abrasive SC-CO2 jet system, CO2 recovery system, and data acquisition system. Now, a series of rock perforating (or case cutting) experiments have been successfully conducted using the setup about pure and abrasive SC-CO2 jet, and the results have proven the great perforating efficiency of SC-CO2 jet and the applications of this setup.

  5. Apolipoprotein CIII overexpression exacerbates diet-induced obesity due to adipose tissue higher exogenous lipid uptake and retention and lower lipolysis rates.

    Science.gov (United States)

    Raposo, Helena F; Paiva, Adriene A; Kato, Larissa S; de Oliveira, Helena C F

    2015-01-01

    Hypertriglyceridemia is a common type of dyslipidemia found in obesity. However, it is not established whether primary hyperlipidemia can predispose to obesity. Evidences have suggested that proteins primarily related to plasma lipoprotein transport, such as apolipoprotein (apo) CIII and E, may significantly affect the process of body fat accumulation. We have previously observed an increased adiposity in response to a high fat diet (HFD) in mice overexpressing apoCIII. Here, we examined the potential mechanisms involved in this exacerbated response of apoCIII mice to the HFD. We measured body energy balance, tissue capacity to store exogenous lipids, lipogenesis and lipolysis rates in non-transgenic and apoCIII overexpressing mice fed a HFD during two months. Food intake, fat excretion and whole body CO2 production were similar in both groups. However, the adipose tissue mass (45 %) and leptin plasma levels (2-fold) were significantly greater in apoCIII mice. Lipogenesis rates were similar, while exogenous lipid retention was increased in perigonadal (2-fold) and brown adipose tissues (40 %) of apoCIII mice. In addition, adipocyte basal lipolysis (55 %) and in vivo lipolysis index (30 %) were significantly decreased in apoCIII mice. A fat tolerance test evidenced delayed plasma triglyceride clearance and greater transient availability of non-esterified fatty acids (NEFA) during the post-prandial state in the apoCIII mice plasma. Thus, apoCIII overexpression resulted in increased NEFA availability to adipose uptake and decreased adipocyte lipolysis, favoring lipid enlargement of adipose depots. We propose that plasma apoCIII levels represent a new risk factor for diet-induced obesity.

  6. Polyethyleneimine-Functionalized Polyamide Imide (Torlon) Hollow-Fiber Sorbents for Post-Combustion CO 2 Capture

    KAUST Repository

    Li, Fuyue Stephanie

    2013-05-24

    Carbon dioxide emitted from existing coal-fired power plants is a major environmental concern due to possible links to global climate change. In this study, we expand upon previous work focused on aminosilane-functionalized polymeric hollow-fiber sorbents by introducing a new class of polyethyleneimine (PEI)-functionalized polymeric hollow-fiber sorbents for post-combustion carbon dioxide capture. Different molecular weight PEIs (Mn≈600, 1800, 10 000, and 60 000) were studied as functional groups on polyamide imide (PAI, Torlon) hollow fibers. This imide ring-opening modification introduces two amide functional groups and was confirmed by FTIR attenuated total reflectance spectroscopy. The carbon dioxide equilibrium sorption capacities of PEI-functionalized Torlon materials were characterized by using both pressure decay and gravimetric sorption methods. For equivalent PEI concentrations, PAI functionalized with lower molecular weight PEI exhibited higher carbon dioxide capacities. The effect of water in the ring-opening reaction was also studied. Up to a critical value, water in the reaction mixture enhanced the degree of functionalization of PEI to Torlon and resulted in higher carbon dioxide uptake within the functionalized material. Above the critical value, roughly 15 % w/w water, the fiber morphology was lost and the fiber was soluble in the solvent. PEI-functionalized (Mn≈600) PAI under optimal reaction conditions was observed to have the highest CO2 uptake: 4.9 g CO2 per 100 g of polymer (1.1 mmol g-1) at 0.1 bar and 35°C with dry 10 % CO2/90 % N2 feed for thermogravimetric analysis. By using water-saturated feeds (10 % CO2/90 % N2 dry basis), CO2 sorption was observed to increase to 6.0 g CO2 per 100 g of sorbent (1.4 mmol g-1). This material also demonstrated stability in cyclic adsorption-desorption operations, even under wet conditions at which some highly effective sorbents tend to lose performance. Thus, PEI-functionalized PAI fibers can be

  7. CO2 fluxes from a tropical neighborhood: sources and sinks

    Science.gov (United States)

    Velasco, E.; Roth, M.; Tan, S.; Quak, M.; Britter, R.; Norford, L.

    2011-12-01

    Cities are the main contributors to the CO2 rise in the atmosphere. The CO2 released from the various emission sources is typically quantified by a bottom-up aggregation process that accounts for emission factors and fossil fuel consumption data. This approach does not consider the heterogeneity and variability of the urban emission sources, and error propagation can result in large uncertainties. In this context, direct measurements of CO2 fluxes that include all major and minor anthropogenic and natural sources and sinks from a specific district can be used to evaluate emission inventories. This study reports and compares CO2 fluxes measured directly using the eddy covariance method with emissions estimated by emissions factors and activity data for a residential neighborhood of Singapore, a highly populated and urbanized tropical city. The flux measurements were conducted during one year. No seasonal variability was found as a consequence of the constant climate conditions of tropical places; but a clear diurnal pattern with morning and late afternoon peaks in phase with the rush-hour traffic was observed. The magnitude of the fluxes throughout daylight hours is modulated by the urban vegetation, which is abundant in terms of biomass but not of land-cover (15%). Even though the carbon uptake by vegetation is significant, it does not exceed the anthropogenic emissions and the monitored district is a net CO2 source of 20.3 ton km-2 day-1 on average. The carbon uptake by vegetation is investigated as the difference between the estimated emissions and the measured fluxes during daytime.

  8. Forest succession at elevated CO2; TOPICAL

    International Nuclear Information System (INIS)

    Clark, James S.; Schlesinger, William H.

    2002-01-01

    We tested hypotheses concerning the response of forest succession to elevated CO2 in the FACTS-1 site at the Duke Forest. We quantified growth and survival of naturally recruited seedlings, tree saplings, vines, and shrubs under ambient and elevated CO2. We planted seeds and seedlings to augment sample sites. We augmented CO2 treatments with estimates of shade tolerance and nutrient limitation while controlling for soil and light effects to place CO2 treatments within the context of natural variability at the site. Results are now being analyzed and used to parameterize forest models of CO2 response

  9. Soot and NOx simultaneous reduction by use of CO2 mixed fuel; Ekika CO2 yokai nenryo ni yoru diesel kikan no susu, NOx no doji teigen

    Energy Technology Data Exchange (ETDEWEB)

    Senda, J; Yokoyama, T; Ikeda, M; Fujimoto, H [Doshisha University, Kyoto (Japan); Ifuku, Y [Kubota Corp., Osaka (Japan)

    1997-10-01

    We propose the new fuel injection system by use of diesel fuel dissolved with CO2 to reduce both soot and NOx simultaneously. In this paper spray combustion characteristics of CO2 mixed fuel is reported. It is revealed that flame temperature and KL factor at the CO2 mixed fuel combustion are lower than at the only n-tridecane combustion due to separation or partly flashing of CO2component. And the result of exhaust gas measurement shows the capability that CO2 mixed fuel is able to reduce both soot and NOx simultaneously. 12 refs., 7 figs., 1 tab.

  10. Synthesis of polyglycocarbonates through polycondensation of glucopyranosides with CO2

    KAUST Repository

    Pati, Debasis

    2017-03-17

    Starting from α-methyl D-glucopyranoside (MDG), three strategies of synthesis of polyglycocarbonates through direct polycondensation with CO2 were tried. Using unprotected MDG for reaction with CO2, water soluble oligoglycocarbonates could be obtained; α-methyl-2,3-di-O-methyl D-glucopyranoside (MDMG) which had its hydroxyls in the C2 and C3 positions protected was also subjected to polycondensation with CO2, affording polyglycocarbonates of limited molar mass due to an equilibrium that prevented the progress of the condensation reaction as in the previous case. Lastly, the polycondensation of MDMG with CO2 and aliphatic or aromatic dihalides was carried out in the presence of Cs2CO3; this resulted in the formation of polyglycocarbonates of rather high molar mass containing either aliphatic or aromatic linkers. The structures of the synthesized monomers and polyglycocarbonates were thoroughly characterized. The thermal properties of the obtained polyglycocarbonates were further investigated by TGA and DSC.

  11. Synthesis of polyglycocarbonates through polycondensation of glucopyranosides with CO2

    KAUST Repository

    Pati, Debasis; Chen, Zuliang; Feng, Xiaoshuang; Hadjichristidis, Nikolaos; Gnanou, Yves

    2017-01-01

    Starting from α-methyl D-glucopyranoside (MDG), three strategies of synthesis of polyglycocarbonates through direct polycondensation with CO2 were tried. Using unprotected MDG for reaction with CO2, water soluble oligoglycocarbonates could be obtained; α-methyl-2,3-di-O-methyl D-glucopyranoside (MDMG) which had its hydroxyls in the C2 and C3 positions protected was also subjected to polycondensation with CO2, affording polyglycocarbonates of limited molar mass due to an equilibrium that prevented the progress of the condensation reaction as in the previous case. Lastly, the polycondensation of MDMG with CO2 and aliphatic or aromatic dihalides was carried out in the presence of Cs2CO3; this resulted in the formation of polyglycocarbonates of rather high molar mass containing either aliphatic or aromatic linkers. The structures of the synthesized monomers and polyglycocarbonates were thoroughly characterized. The thermal properties of the obtained polyglycocarbonates were further investigated by TGA and DSC.

  12. CO2 Fixation by Membrane Separated NaCl Electrolysis

    DEFF Research Database (Denmark)

    Park, Hyun Sic; Lee, Ju Sung; Han, Junyoung

    2015-01-01

    for converting CO2 into CaCO3 requires high temperature and high pressure as reaction conditions. This study proposes a method to fixate CaCO3 stably by using relatively less energy than existing methods. After forming NaOH absorbent solution through electrolysis of NaCl in seawater, CaCO3 was precipitated...... crystal product was high-purity calcite. The study shows a successful method for fixating CO2 by reducing carbon dioxide released into the atmosphere while forming high-purity CaCO3.......Atmospheric concentrations of carbon dioxide (CO2), a major cause of global warming, have been rising due to industrial development. Carbon capture and storage (CCS), which is regarded as the most effective way to reduce such atmospheric CO2 concentrations, has several environmental and technical...

  13. Crassulacean acid metabolism, CO2-recycling, and tissue desiccation in the Mexican epiphyte Tillandsia schiedeana Steud (Bromeliaceae).

    Science.gov (United States)

    Martin, C E; Adams, W W

    1987-01-01

    After 23 days without water in a greenhouse, rates of nocturnal CO2 uptake in Tillandsia schiedeana decreased substantially and maximum rates occurred later in the dark period eventually coinciding with the onset of illumination. Nocturnal CO2 uptake accounted for less than half the total nighttime increase in acidity measured in well-watered plants. With increased tissue desiccation, only 11-12% of measured acid accumulation was attributable to atmospheric CO2 uptake. Plants desiccated for 30 days regained initial levels of nocturnal acid accumulation and CO2 uptake after rehydration for 10h. These results stress the importance of CO2 recycling via CAM in this epiphytic bromeliad, especially during droughts.

  14. CO2 clearance by membrane lungs.

    Science.gov (United States)

    Sun, Liqun; Kaesler, Andreas; Fernando, Piyumindri; Thompson, Alex J; Toomasian, John M; Bartlett, Robert H

    2018-05-01

    Commercial membrane lungs are designed to transfer a specific amount of oxygen per unit of venous blood flow. Membrane lungs are much more efficient at removing CO 2 than adding oxygen, but the range of CO 2 transfer is rarely reported. Commercial membrane lungs were studied with the goal of evaluating CO 2 removal capacity. CO 2 removal was measured in 4 commercial membrane lungs under standardized conditions. CO 2 clearance can be greater than 4 times that of oxygen at a given blood flow when the gas to blood flow ratio is elevated to 4:1 or 8:1. The CO 2 clearance was less dependent on surface area and configuration than oxygen transfer. Any ECMO system can be used for selective CO 2 removal.

  15. PEAT-CO2. Assessment of CO2 emissions from drained peatlands in SE Asia

    International Nuclear Information System (INIS)

    Hooijer, A.; Silvius, M.; Woesten, H.; Page, S.

    2006-12-01

    Forested tropical peatlands in SE Asia store at least 42,000 Megatonnes of soil carbon. This carbon is increasingly released to the atmosphere due to drainage and fires associated with plantation development and logging. Peatlands make up 12% of the SE Asian land area but account for 25% of current deforestation. Out of 27 million hectares of peatland, 12 million hectares (45%) are currently deforested and mostly drained. One important crop in drained peatlands is palm oil, which is increasingly used as a biofuel in Europe. In the PEAT-CO2 project, present and future emissions from drained peatlands were quantified using the latest data on peat extent and depth, present and projected land use and water management practice, decomposition rates and fire emissions. It was found that current likely CO2 emissions caused by decomposition of drained peatlands amounts to 632 Mt/y (between 355 and 874 Mt/y). This emission will increase in coming decades unless land management practices and peatland development plans are changed, and will continue well beyond the 21st century. In addition, over 1997-2006 an estimated average of 1400 Mt/y in CO2 emissions was caused by peatland fires that are also associated with drainage and degradation. The current total peatland CO2 emission of 2000 Mt/y equals almost 8% of global emissions from fossil fuel burning. These emissions have been rapidly increasing since 1985 and will further increase unless action is taken. Over 90% of this emission originates from Indonesia, which puts the country in 3rd place (after the USA and China) in the global CO2 emission ranking. It is concluded that deforested and drained peatlands in SE Asia are a globally significant source of CO2 emissions and a major obstacle to meeting the aim of stabilizing greenhouse gas emissions, as expressed by the international community. It is therefore recommended that international action is taken to help SE Asian countries, especially Indonesia, to better conserve

  16. Numerical Simulation of Natural Convection in Heterogeneous Porous media for CO2 Geological Storage

    NARCIS (Netherlands)

    Ranganathan, P.; Farajzadeh, R.; Bruining, J.; Zitha, P.L.J.

    2012-01-01

    We report a modeling and numerical simulation study of density-driven natural convection during geological CO2 storage in heterogeneous formations. We consider an aquifer or depleted oilfield overlain by gaseous CO2, where the water density increases due to CO2 dissolution. The heterogeneity of the

  17. Extraction of stevia glycosides with CO2 + water, CO2 + ethanol, and CO2 + water + ethanol

    Directory of Open Access Journals (Sweden)

    A. Pasquel

    2000-09-01

    Full Text Available Stevia leaves are an important source of natural sugar substitute. There are some restrictions on the use of stevia extract because of its distinctive aftertaste. Some authors attribute this to soluble material other than the stevia glycosides, even though it is well known that stevia glycosides have to some extent a bitter taste. Therefore, the purpose of this work was to develop a process to obtain stevia extract of a better quality. The proposed process includes two steps: i Pretreatment of the leaves by SCFE; ii Extraction of the stevia glycosides by SCFE using CO2 as solvent and water and/or ethanol as cosolvent. The mean total yield for SCFE pretreatment was 3.0%. The yields for SCFE with cosolvent of stevia glycosides were below 0.50%, except at 120 bar, 16°C, and 9.5% (molar of water. Under this condition, total yield was 3.4%. The quality of the glycosidic fraction with respect to its capacity as sweetener was better for the SCFE extract as compared to extract obtained by the conventional process. The overall extraction curves were well described by the Lack extended model.

  18. Power stabilized CO2 gas transport laser

    International Nuclear Information System (INIS)

    Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

    1975-01-01

    The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

  19. Anterior capsulotomy using the CO2 laser

    Science.gov (United States)

    Barak, Adiel; Ma-Naim, Tova; Rosner, Mordechai; Eyal, Ophir; Belkin, Michael

    1998-06-01

    Continuous circular capsulorhexis (CCC) is the preferred technique for removal of the anterior capsule during cataract surgery due to this technique assuring accurate centration of the intraocular lens. During modern cataract surgery, especially with small or foldable intra ocular lenses, centration of the lens is obligatory. Radial tears at the margin of an anterior capsulotomy may be associated with the exit of at least one loop of an intraocular lens out of the capsular bag ('pea pod' effect) and its subsequent decentration. The anterior capsule is more likely to ream intact if the continuous circular capsulorhexis (CCC) technique is used. Although manual capsulorhexis is an ideal anterior capsulectomy technique for adults, many ophthalmologists are still uncomfortable with it and find it difficult to perform, especially in complicated cases such as these done behind small pupil, cataract extraction in children and pseudoexfoliation syndrome. We have developed a technique using a CO2 laser system for safe anterior capsulotomy and tested it in animal eyes.

  20. Year-round Regional CO2 Fluxes from Boreal and Tundra Ecosystems in Alaska

    Science.gov (United States)

    Commane, R.; Lindaas, J.; Benmergui, J. S.; Luus, K. A.; Chang, R. Y. W.; Daube, B. C.; Euskirchen, E. S.; Henderson, J.; Karion, A.; Miller, J. B.; Miller, S. M.; Parazoo, N.; Randerson, J. T.; Sweeney, C.; Tans, P. P.; Thoning, K. W.; Veraverbeke, S.; Miller, C. E.; Wofsy, S. C.

    2016-12-01

    High-latitude ecosystems could release large amounts of carbon dioxide (CO2) to the atmosphere in a warmer climate. We derive temporally and spatially resolved year-round CO2 fluxes in Alaska from a synthesis of airborne and tower CO2 observations in 2012-2014. We find that tundra ecosystems were net sources of atmospheric CO2. We discuss these flux estimates in the context of long-term CO2 measurements at Barrow, AK, to asses the long term trend in carbon fluxes in the Arctic. Many Earth System Models incorrectly simulate net carbon uptake in Alaska presently. Our results imply that annual net emission of CO2 to the atmosphere may have increased markedly in this region of the Arctic in response to warming climate, supporting the view that climate-carbon feedback is strongly positive in the high Arctic.

  1. Variability in soil CO2 production and surface CO2 efflux across riparian-hillslope transitions

    Science.gov (United States)

    Vincent Jerald. Pacific

    2007-01-01

    The spatial and temporal controls on soil CO2 production and surface CO2 efflux have been identified as an outstanding gap in our understanding of carbon cycling. I investigated both the spatial and temporal variability of soil CO2 concentrations and surface CO2 efflux across eight topographically distinct riparian-hillslope transitions in the ~300 ha subalpine upper-...

  2. CO2 flux from Javanese mud volcanism.

    Science.gov (United States)

    Queißer, M; Burton, M R; Arzilli, F; Chiarugi, A; Marliyani, G I; Anggara, F; Harijoko, A

    2017-06-01

    Studying the quantity and origin of CO 2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO 2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO 2 with a volume fraction of at least 16 vol %. A lower limit CO 2 flux of 1.4 kg s -1 (117 t d -1 ) was determined, in line with the CO 2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO 2 flux of 3 kt d -1 , comparable with the expected back-arc efflux of magmatic CO 2 . After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO 2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO 2 , with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man-portable active remote sensing instruments for probing natural gas releases, enabling bottom-up quantification of CO 2 fluxes.

  3. Estimates of evapotranspiration and CO2 fluxes in a biofiltration system

    Science.gov (United States)

    Daly, E.; Niculescu, A.; Beringer, J.; Deletic, A.

    2009-12-01

    Biofiltration systems (or biofilters, bioretention systems or rain gardens) have been adopted to improve the quality of urban aquatic ecosystems and to reduce volumes and peaks of stormwater runoff. Given their good performances, it is likely that the implementation of such systems in urban areas will greatly increase in the future. As an example, the city of Melbourne (Australia) is planning to install 10,000 biofiltration systems within its area by 2013. Because biofiltration systems are commonly installed in urban areas, along roads and highways, their vegetation is often under atmospheric CO2 concentrations higher than average ambient conditions (i.e., above 380 ppm). Additionally, since these systems are designed to receive runoff from large catchment areas (typically around 50-100 times the area of the biofilter), their vegetation rarely experiences water and nitrogen limitations. These surrounding environmental conditions suggest that biofilters might experience high evapotranspiration (ET) rates and CO2 assimilation via photosynthesis, which could potentially provide benefits to the local microclimate in terms of temperature reduction (cooling due to enhanced ET) and CO2 uptake from the atmosphere, in addition to the benefit related to stormwater treatment. These hypotheses have been strengthen by preliminary tests based on laboratory experiments with soil columns vegetated with C.appressa, in which ET has been estimated to be as high as 0.7-0.8 cm per day. To further study these processes, several measurements are being performed in a biofiltration system installed at Monash University, Clayton Campus (Melbourne, VIC). This biofilter receives runoff diverted from a 100% impervious car park and discharges the treated stormwater to an adjacent pond. A chamber that encloses part of the vegetation in the biofilter has been constructed to monitor water and greenhouse gas fluxes. Preliminary results on daily patterns of water and CO2 fluxes within the system in

  4. Explaining CO2 fluctuations observed in snowpacks

    Science.gov (United States)

    Graham, Laura; Risk, David

    2018-02-01

    Winter soil carbon dioxide (CO2) respiration is a significant and understudied component of the global carbon (C) cycle. Winter soil CO2 fluxes can be surprisingly variable, owing to physical factors such as snowpack properties and wind. This study aimed to quantify the effects of advective transport of CO2 in soil-snow systems on the subdiurnal to diurnal (hours to days) timescale, use an enhanced diffusion model to replicate the effects of CO2 concentration depletions from persistent winds, and use a model-measure pairing to effectively explore what is happening in the field. We took continuous measurements of CO2 concentration gradients and meteorological data at a site in the Cape Breton Highlands of Nova Scotia, Canada, to determine the relationship between wind speeds and CO2 levels in snowpacks. We adapted a soil CO2 diffusion model for the soil-snow system and simulated stepwise changes in transport rate over a broad range of plausible synthetic cases. The goal was to mimic the changes we observed in CO2 snowpack concentration to help elucidate the mechanisms (diffusion, advection) responsible for observed variations. On subdiurnal to diurnal timescales with varying winds and constant snow levels, a strong negative relationship between wind speed and CO2 concentration within the snowpack was often identified. Modelling clearly demonstrated that diffusion alone was unable to replicate the high-frequency CO2 fluctuations, but simulations using above-atmospheric snowpack diffusivities (simulating advective transport within the snowpack) reproduced snow CO2 changes of the observed magnitude and speed. This confirmed that wind-induced ventilation contributed to episodic pulsed emissions from the snow surface and to suppressed snowpack concentrations. This study improves our understanding of winter CO2 dynamics to aid in continued quantification of the annual global C cycle and demonstrates a preference for continuous wintertime CO2 flux measurement systems.

  5. Metal-Organic Framework-Stabilized CO2/Water Interfacial Route for Photocatalytic CO2 Conversion.

    Science.gov (United States)

    Luo, Tian; Zhang, Jianling; Li, Wei; He, Zhenhong; Sun, Xiaofu; Shi, Jinbiao; Shao, Dan; Zhang, Bingxing; Tan, Xiuniang; Han, Buxing

    2017-11-29

    Here, we propose a CO 2 /water interfacial route for photocatalytic CO 2 conversion by utilizing a metal-organic framework (MOF) as both an emulsifier and a catalyst. The CO 2 reduction occurring at the CO 2 /water interface produces formate with remarkably enhanced efficiency as compared with that in conventional solvent. The route is efficient, facile, adjustable, and environmentally benign, which is applicable for the CO 2 transformation photocatalyzed by different kinds of MOFs.

  6. Effects of experimental nitrogen fertilization on planktonic metabolism and CO2 flux in a hypereutrophic hardwater lake.

    Directory of Open Access Journals (Sweden)

    Matthew J Bogard

    Full Text Available Hardwater lakes are common in human-dominated regions of the world and often experience pollution due to agricultural and urban effluent inputs of inorganic and organic nitrogen (N. Although these lakes are landscape hotspots for CO2 exchange and food web carbon (C cycling, the effect of N enrichment on hardwater lake food web functioning and C cycling patterns remains unclear. Specifically, it is unknown if different eutrophication scenarios (e.g., modest non point vs. extreme point sources yield consistent effects on auto- and heterotrophic C cycling, or how biotic responses interact with the inorganic C system to shape responses of air-water CO2 exchange. To address this uncertainty, we induced large metabolic gradients in the plankton community of a hypereutrophic hardwater Canadian prairie lake by adding N as urea (the most widely applied agricultural fertilizer at loading rates of 0, 1, 3, 8 or 18 mg N L-1 week-1 to 3240-L, in-situ mesocosms. Over three separate 21-day experiments, all treatments of N dramatically increased phytoplankton biomass and gross primary production (GPP two- to six-fold, but the effects of N on autotrophs plateaued at ~3 mg N L-1. Conversely, heterotrophic metabolism increased linearly with N fertilization over the full treatment range. In nearly all cases, N enhanced net planktonic uptake of dissolved inorganic carbon (DIC, and increased the rate of CO2 influx, while planktonic heterotrophy and CO2 production only occurred in the highest N treatments late in each experiment, and even in these cases, enclosures continued to in-gas CO2. Chemical effects on CO2 through calcite precipitation were also observed, but similarly did not change the direction of net CO2 flux. Taken together, these results demonstrate that atmospheric exchange of CO2 in eutrophic hardwater lakes remains sensitive to increasing N loading and eutrophication, and that even modest levels of N pollution are capable of enhancing autotrophy and CO

  7. Advanced technology development reducing CO2 emissions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Sup

    2010-09-15

    Responding to Korean government policies on green growth and global energy/ environmental challenges, SK energy has been developing new technologies to reduce CO2 emissions by 1) CO2 capture and utilization, 2) efficiency improvement, and 3) Li-ion batteries. The paper introduces three advanced technologies developed by SK energy; GreenPol, ACO, and Li-ion battery. Contributing to company vision, a more energy and less CO2, the three technologies are characterized as follows. GreenPol utilizes CO2 as a feedstock for making polymer. Advanced Catalytic Olefin (ACO) reduces CO2 emission by 20% and increase olefin production by 17%. Li-ion Batteries for automotive industries improves CO2 emission.

  8. Drone Detects Hotspots of Radiation and CO2 Outgassing

    Science.gov (United States)

    Takac, M.; Kletetschka, G.

    2016-12-01

    Market availability of environmental sensors and drones allow drones to become part of the education activities promoting environmental science both in high schools and grade schools. Here we provide one mode of drone operation for potential use in educational framework.Drone can carry devices that are capable of measuring various parameters of the environment. Commercial radiation and gas (CO2) sensors can be attached to the commercial drone. Our specific drone acquired data set of CO2 measurements over the natural outgassing of CO2 and another set of measurements over old uranium mine. Measurements of CO2 gave a poor signal to noise ratio. Its sensitivity, however, was enough to detect an increase in CO2 in the closed room with humans present compared to the fresh air outside. We could measure an increase of CO2 when directly over the source of natural CO2 outburst. Our data showed that CO2 concentration quickly dilutes in air few meters from the source to concentrations that are within the noise limit. However, the radiation measurements provided a map that correlates well with radiation survey obtained by ground measurements with more sophisticated instrument. We used the most common conventional drone, which is on the market and highly effective personal dosimeter, which can also be used for fire and rescue for its durability. Experimental field measurements were done at Třebsko site, where a map of radioactivity using standard spot measurements was already done. A field experiment was done in winter months when demand for the drone was higher due to cold and wet weather. We tested profiles and height versus the intensity of the recorded signal measurements. We consulted our results and ability to measure radioactivity with the regional fire-fighting units headquarters and verify the applicability and use of this technology for their needs.

  9. Diffuse soil CO_2 degassing from Linosa island

    Directory of Open Access Journals (Sweden)

    Dario Cellura

    2014-06-01

    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 Normal 0 14 false false false IT X-NONE X-NONE MicrosoftInternetExplorer4 Herein, we present and discuss the result of 148 measurements of soil CO2 flux performed for the first time in Linosa island (Sicily Channel, Italy, a Plio-Pleistocene volcanic complex no longer active but still of interest owing to its location within a seismically active portion of the Sicily Channel rift system. The main purpose of this survey was to assess the occurrence of CO2 soil degassing, and compare flux estimations from this island with data of soil degassing from worldwide active volcanic as well as non-volcanic areas. To this aim soil CO2 fluxes were measured over a surface of about 4.2 km2 covering ~80% of the island. The soil CO2 degassing was observed to be mainly concentrated in the eastern part of the island likely due to volcano-tectonic lineaments, the presence of which is in good agreement with the known predominant regional faults system. Then, the collected data were interpreted using sequential Gaussian simulation that allowed estimating the total CO2 emissions of the island. Results show low levels of CO2 emissions from the soil of the island (~55 ton d-1 compared with CO2 emissions of currently active volcanic areas, such as Miyakejima (Japan and Vulcano (Italy. Results from this study suggest that soil degassing in Linosa is mainly fed by superficial organic activity with a moderate contribution of a deep CO2 likely driven by NW-SE trending active tectonic structures in the eastern part of the island.

  10. Cost evaluation of CO2 sequestration by aqueous mineral carbonation

    International Nuclear Information System (INIS)

    Huijgen, Wouter J.J.; Comans, Rob N.J.; Witkamp, Geert-Jan

    2007-01-01

    A cost evaluation of CO 2 sequestration by aqueous mineral carbonation has been made using either wollastonite (CaSiO 3 ) or steel slag as feedstock. First, the process was simulated to determine the properties of the streams as well as the power and heat consumption of the process equipment. Second, a basic design was made for the major process equipment, and total investment costs were estimated with the help of the publicly available literature and a factorial cost estimation method. Finally, the sequestration costs were determined on the basis of the depreciation of investments and variable and fixed operating costs. Estimated costs are 102 and 77 EUR/ton CO 2 net avoided for wollastonite and steel slag, respectively. For wollastonite, the major costs are associated with the feedstock and the electricity consumption for grinding and compression (54 and 26 EUR/ton CO 2 avoided, respectively). A sensitivity analysis showed that additional influential parameters in the sequestration costs include the liquid-to-solid ratio in the carbonation reactor and the possible value of the carbonated product. The sequestration costs for steel slag are significantly lower due to the absence of costs for the feedstock. Although various options for potential cost reduction have been identified, CO 2 sequestration by current aqueous carbonation processes seems expensive relative to other CO 2 storage technologies. The permanent and inherently safe sequestration of CO 2 by mineral carbonation may justify higher costs, but further cost reductions are required, particularly in view of (current) prices of CO 2 emission rights. Niche applications of mineral carbonation with a solid residue such as steel slag as feedstock and/or a useful carbonated product hold the best prospects for an economically feasible CO 2 sequestration process. (author)

  11. Modeling Silicate Weathering for Elevated CO2 and Temperature

    Science.gov (United States)

    Bolton, E. W.

    2016-12-01

    A reactive transport model (RTM) is used to assess CO2 drawdown by silicate weathering over a wide range of temperature, pCO2, and infiltration rates for basalts and granites. Although RTM's have been used extensively to model weathering of basalts and granites for present-day conditions, we extend such modeling to higher CO2 that could have existed during the Archean and Proterozoic. We also consider a wide range of surface temperatures and infiltration rates. We consider several model basalt and granite compositions. We normally impose CO2 in equilibrium with the various atmospheric ranges modeled and CO2 is delivered to the weathering zone by aqueous transport. We also consider models with fixed CO2 (aq) throughout the weathering zone as could occur in soils with partial water saturation or with plant respiration, which can strongly influence pH and mineral dissolution rates. For the modeling, we use Kinflow: a model developed at Yale that includes mineral dissolution and precipitation under kinetic control, aqueous speciation, surface erosion, dynamic porosity, permeability, and mineral surface areas via sub-grid-scale grain models, and exchange of volatiles at the surface. Most of the modeling is done in 1D, but some comparisons to 2D domains with heterogeneous permeability are made. We find that when CO2 is fixed only at the surface, the pH tends toward higher values for basalts than granites, in large part due to the presence of more divalent than monovalent cations in the primary minerals, tending to decrease rates of mineral dissolution. Weathering rates increase (as expected) with increasing CO2 and temperature. This modeling is done with the support of the Virtual Planetary Laboratory.

  12. Preliminary Studies of Two-Phase Reactive Process of Sodium-CO2 in S-CO2 Power Conversion Cycle Coupled to SFR System

    International Nuclear Information System (INIS)

    Jung, Hwa Young; Ahn, Yoon Han; Lee, You Ho; Lee, Jeong Ik

    2013-01-01

    As a competing alternative to the steam Rankine cycle, the supercritical CO 2 (S-CO 2 ) Brayton cycle has been highlighted due to its high thermal efficiency, compact turbomachinery and heat exchangers sizes, and the reduced risk of SWRs. While the reduced risk of an SWR is considered as the one of most pronounced benefits of S-CO 2 Brayton cycle, there is still an interaction problem between liquid sodium and CO 2 . Although the chemical interaction between liquid sodium and CO 2 demonstrates less serious potential risks than those of a SWR, the Na/CO 2 interaction should be understood to evaluate safety and reliability of Intermediate Heat eXchanger (IHX). A noticeable characteristic of the reaction environment is that there is a large pressure difference between the liquid sodium and CO 2 side by about 1 and 200 bar, respectively. This would imply that the presence of a micro-crack in a heat exchanger tube will cause a high-pressure leak of CO 2 into liquid sodium side. Although the Na/CO 2 interaction may play an important role in the safety of the SFR reactor system, there has not yet been any research on understanding Na/CO 2 reaction by leakage through IHX. For this problem, the Korea Advanced Institute of Science and Technology (KAIST) research team is studying the mechanism of CO 2 leakage and Na/CO 2 interaction in more details. The KAIST research team developed the MATLAB code, KAIST H XD, which can be used to design and evaluate performance of a heat exchanger of an S-CO 2 cycle. The size of heat exchanger and the amount of CO 2 in the cycle are calculated from the KAIST H XD code to estimate the amount of reaction products in Na/CO 2 interaction as well as liquid sodium

  13. Long-term surface pCO2 trends from observations and models

    International Nuclear Information System (INIS)

    Tjiputra, Jerry F.; Olsen, Are; Heinze, Christoph; Bopp, Laurent; Roy, Tilla

    2014-01-01

    We estimate regional long-term surface ocean pCO 2 growth rates using all available underway and bottled biogeochemistry data collected over the past four decades. These observed regional trends are compared with those simulated by five state-of-the-art Earth system models over the historical period. Oceanic pCO 2 growth rates faster than the atmospheric growth rates indicate decreasing atmospheric CO 2 uptake, while ocean pCO 2 growth rates slower than the atmospheric growth rates indicate increasing atmospheric CO 2 uptake. Aside from the western sub-polar North Pacific and the subtropical North Atlantic, our analysis indicates that the current observation-based basin-scale trends may be underestimated, indicating that more observations are needed to determine the trends in these regions. Encouragingly, good agreement between the simulated and observed pCO 2 trends is found when the simulated fields are sub sampled with the observational coverage. In agreement with observations, we see that the simulated pCO 2 trends are primarily associated with the increase in surface dissolved inorganic carbon (DIC) associated with atmospheric carbon uptake, and in part by warming of the sea surface. Under the RCP8.5 future scenario, DIC continues to be the dominant driver of pCO 2 trends, with little change in the relative contribution of SST. However, the changes in the hydrological cycle play an increasingly important role. For the contemporary (1970-2011) period, the simulated regional pCO 2 trends are lower than the atmospheric growth rate over 90% of the ocean. However, by year 2100 more than 40% of the surface ocean area has a higher oceanic pCO 2 trend than the atmosphere, implying a reduction in the atmospheric CO 2 uptake rate. The fastest pCO 2 growth rates are projected for the sub-polar North Atlantic, while the high-latitude Southern Ocean and eastern equatorial Pacific have the weakest growth rates, remaining below the atmospheric pCO 2 growth rate. Our work

  14. Long-term surface pCO2 trends from observations and models

    Directory of Open Access Journals (Sweden)

    Jerry F. Tjiputra

    2014-05-01

    Full Text Available We estimate regional long-term surface ocean pCO2 growth rates using all available underway and bottled biogeochemistry data collected over the past four decades. These observed regional trends are compared with those simulated by five state-of-the-art Earth system models over the historical period. Oceanic pCO2 growth rates faster than the atmospheric growth rates indicate decreasing atmospheric CO2 uptake, while ocean pCO2 growth rates slower than the atmospheric growth rates indicate increasing atmospheric CO2 uptake. Aside from the western subpolar North Pacific and the subtropical North Atlantic, our analysis indicates that the current observation-based basin-scale trends may be underestimated, indicating that more observations are needed to determine the trends in these regions. Encouragingly, good agreement between the simulated and observed pCO2 trends is found when the simulated fields are subsampled with the observational coverage. In agreement with observations, we see that the simulated pCO2 trends are primarily associated with the increase in surface dissolved inorganic carbon (DIC associated with atmospheric carbon uptake, and in part by warming of the sea surface. Under the RCP8.5 future scenario, DIC continues to be the dominant driver of pCO2 trends, with little change in the relative contribution of SST. However, the changes in the hydrological cycle play an increasingly important role. For the contemporary (1970–2011 period, the simulated regional pCO2 trends are lower than the atmospheric growth rate over 90% of the ocean. However, by year 2100 more than 40% of the surface ocean area has a higher oceanic pCO2 trend than the atmosphere, implying a reduction in the atmospheric CO2 uptake rate. The fastest pCO2 growth rates are projected for the subpolar North Atlantic, while the high-latitude Southern Ocean and eastern equatorial Pacific have the weakest growth rates, remaining below the atmospheric pCO2 growth rate. Our work

  15. CO2 Allowance and Electricity Price Interaction

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    With the introduction of CO2 emission constraints on power generators in the European Union, climate policy is starting to have notable effects on energy markets. This paper sheds light on the links between CO2 prices, electricity prices, and electricity costs to industry. It is based on a series of interviews with industrial and electricity stakeholders, as well as a rich literature seeking to estimate the exact effect of CO2 prices on electricity prices.

  16. CO2 sequestration: Storage capacity guideline needed

    Science.gov (United States)

    Frailey, S.M.; Finley, R.J.; Hickman, T.S.

    2006-01-01

    Petroleum reserves are classified for the assessment of available supplies by governmental agencies, management of business processes for achieving exploration and production efficiency, and documentation of the value of reserves and resources in financial statements. Up to the present however, the storage capacity determinations made by some organizations in the initial CO2 resource assessment are incorrect technically. New publications should thus cover differences in mineral adsorption of CO2 and dissolution of CO2 in various brine waters.

  17. Economic effects on taxing CO2 emissions

    International Nuclear Information System (INIS)

    Haaparanta, P.; Jerkkola, J.; Pohjola, J.

    1996-01-01

    The CO 2 emissions can be reduced by using economic instruments, like carbon tax. This project included two specific questions related to CO 2 taxation. First one was the economic effects of increasing CO 2 tax and decreasing other taxes. Second was the economic adjustment costs of reducing net emissions instead of gross emissions. A computable general equilibrium (CGE) model was used in this analysis. The study was taken place in Helsinki School of Economics

  18. Porous carbon derived via KOH activation of a hypercrosslinked porous organic polymer for efficient CO_2, CH_4, H_2 adsorptions and high CO_2/N_2 selectivity

    International Nuclear Information System (INIS)

    Modak, Arindam; Bhaumik, Asim

    2015-01-01

    Microporous carbon having Brunauer-Emmett-Teller (BET) surface area of 2186 m"2 g"−"1 and micropore volume of 0.85 cm"3 g"−"1 has been synthesized via KOH induced high temperature carbonization of a non-conjugated hypercrosslinked organic polymer. Owing to the templating and activation by KOH, we have succeeded in making a microporous carbon from this porous polymer and the resultant carbon material showed high uptake for CO_2 (7.6 mmol g"−"1) and CH_4 (2.4 mmol g"−"1) at 1 atm, 273 K together with very good selectivity for the CO_2/N_2 (30.2) separation. Furthermore, low pressure (1 atm) H_2 (2.6 wt%, 77 K) and water uptake (57.4 wt%, 298 K) ability of this polymer derived porous activated carbon is noteworthy. - Graphical abstract: Microporous carbon with BET surface area of 2186 m"2 g"−"1 has been synthesized via KOH activation of a porous organic polymer and it showed high uptake for CO_2 (7.6 mmol g"−"1), CH_4 (2.4 mmol g"−"1) and H_2 (2.6 wt%) at 1 atm together with very good selectivity for CO_2. - Highlights: • Porous carbon from hypercrosslinked organic polymer. • KOH activated carbon with BET surface area 2186 m"2 g"−"1. • High CO2 uptake (7.6 mmol g"−"1) and CO_2/N_2 selectivity (30.2). • Porous carbon also showed high H_2 (2.6 wt%) and H_2O (57.4 wt%) uptakes.

  19. CO2-Induced Changes in Wheat Grain Composition: Meta-Analysis and Response Functions

    Directory of Open Access Journals (Sweden)

    Malin C. Broberg

    2017-04-01

    Full Text Available Elevated carbon dioxide (eCO2 stimulates wheat grain yield, but simultaneously reduces protein/nitrogen (N concentration. Also, other essential nutrients are subject to change. This study is a synthesis of wheat experiments with eCO2, estimating the effects on N, minerals (B, Ca, Cd, Fe, K, Mg, Mn, Na, P, S, Zn, and starch. The analysis was performed by (i deriving response functions to assess the gradual change in element concentration with increasing CO2 concentration, (ii meta-analysis to test the average magnitude and significance of observed effects, and (iii relating CO2 effects on minerals to effects on N and grain yield. Responses ranged from zero to strong negative effects of eCO2 on mineral concentration, with the largest reductions for the nutritionally important elements of N, Fe, S, Zn, and Mg. Together with the positive but small and non-significant effect on starch concentration, the large variation in effects suggests that CO2-induced responses cannot be explained only by a simple dilution model. To explain the observed pattern, uptake and transport mechanisms may have to be considered, along with the link of different elements to N uptake. Our study shows that eCO2 has a significant effect on wheat grain stoichiometry, with implications for human nutrition in a world of rising CO2.

  20. Amine–mixed oxide hybrid materials for carbon dioxide adsorption from CO2/H2 mixture

    Science.gov (United States)

    Ravi, Navin; Aishah Anuar, Siti; Yusuf, Nur Yusra Mt; Isahak, Wan Nor Roslam Wan; Shahbudin Masdar, Mohd

    2018-05-01

    Bio-hydrogen mainly contains hydrogen and high level of carbon dioxide (CO2). High concentration of CO2 lead to a limitation especially in fuel cell application. In this study, the amine-mixed oxide hybrid materials for CO2 separation from bio-hydrogen model (50% CO2:50% H2) have been studied. Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) characterizations showed that the amine–mixed oxide hybrid materials successfully adsorbed CO2 physically with no chemical adsorption evidence. The dry gas of CO2/H2 mixture adsorbed physically on amine–CuO–MgO hybrid material. No carbonates were detected after several times of adsorption, which indicated the good recyclability of adsorbents. The adsorbent system of diethanolamine (DEA)/15% CuO–75% MgO showed the highest CO2 adsorption capacity of 21.2 wt% due to the presence of polar substance on MgO surface, which can adsorb CO2 at ambient condition. The alcohol group of DEA can enhance the CO2 solubility on the adsorbent surface. In the 20% CuO–50% MgO adsorbent system, DEA as amine type showed a high CO2 adsorption of 19.4 wt%. The 10% amine loading system showed that the DEA adsorption system provided high CO2 adsorption. The BET analysis confirmed that a high amine loading contributed to the decrease in CO2 adsorption due to the low surface area of the adsorbent system.

  1. The non-steady state oceanic CO2 signal: its importance, magnitude and a novel way to detect it

    Directory of Open Access Journals (Sweden)

    B. I. McNeil

    2013-04-01

    Full Text Available The role of the ocean has been pivotal in modulating rising atmospheric CO2 levels since the industrial revolution, sequestering nearly half of all fossil-fuel derived CO2 emissions. Net oceanic uptake of CO2 has roughly doubled between the 1960s (~1 Pg C yr−1 and 2000s (~2 Pg C yr−1, with expectations that it will continue to absorb even more CO2 with rising future atmospheric CO2 levels. However, recent CO2 observational analyses along with numerous model predictions suggest the rate of oceanic CO2 uptake is already slowing, largely as a result of a natural decadal-scale outgassing signal. This recent CO2 outgassing signal represents a significant shift in our understanding of the oceans role in modulating atmospheric CO2. Current tracer-based estimates for the ocean storage of anthropogenic CO2 assume the ocean circulation and biology is in steady state, thereby missing the new and potentially important "non-steady state" CO2 outgassing signal. By combining data-based techniques that assume the ocean is in a steady state, with techniques that constrain the net oceanic CO2 uptake signal, we show how to extract the non-steady state CO2 signal from observations. Over the entire industrial era, the non-steady state CO2 outgassing signal (~13 ± 10 Pg C is estimated to represent about 9% of the total net CO2 inventory change (~142 Pg C. However, between 1989 and 2007, the non-steady state CO2 outgassing signal (~6.3 Pg C has likely increased to be ~18% of net oceanic CO2 storage over that period (~36 Pg C. The present uncertainty of our data-based techniques for oceanic CO2 uptake limit our capacity to quantify the non-steady state CO2 signal, however with more data and better certainty estimates across a range of diverse methods, this important and growing CO2 signal could be better constrained in the future.

  2. Experimental Ion Mobility measurements in Ne-CO$_2$ and CO$_2$-N$_2$ mixtures

    CERN Document Server

    Encarnação, P.M.C.C.; Veenhof, R.; Neves, P.N.B.; Santos, F.P.; Trindade, A.M.F.; Borges, F.I.G.M.; Conde, C.A.N.

    2016-01-01

    In this paper we present the experimental results for the mobility, K0, of ions in neon-carbon dioxide (Ne-CO2) and carbon dioxide-nitrogen (CO2-N2) gaseous mixtures for total pressures ranging from 8–12 Torr, reduced electric fields in the 10–25 Td range, at room temperature. Regarding the Ne-CO2 mixture only one peak was observed for CO2 concentrations above 25%, which has been identified as an ion originated in CO2, while below 25% of CO2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 ± 0.05 and 1.07 ± 0.01 cm2V−1s−1 in the 10%-99% interval of CO2, and from 4.61 ± 0.19 to 3.00 ± 0.09 cm2V−1s−1 for the second peak observed (10%–25% of CO2). For the CO2-N2, the time-of-arrival spectra displayed only one peak for CO2 concentrations above 10%, which was attributed to ions originated in CO2, namely CO2+(CO2), with a second peak appearing for CO2 concentrations below 10%. This secon...

  3. Plant uptake of dual-labeled organic N biased by inorganic C uptake

    DEFF Research Database (Denmark)

    Rasmussen, Jim; Sauheitl, Leopold; Eriksen, Jørgen

    2010-01-01

    glycine or CO2-3 , but found no differences in uptake rates between these C-sources. The uptake of inorganic C to the shoot tissue was higher for maize grown in full light compared to shading, which indicates a passive uptake of inorganic C with water. We conclude that uptake of inorganic C produced...

  4. Increased N2O emission by inhibited plant growth in the CO2 leaked soil environment: Simulation of CO2 leakage from carbon capture and storage (CCS) site.

    Science.gov (United States)

    Kim, You Jin; He, Wenmei; Ko, Daegeun; Chung, Haegeun; Yoo, Gayoung

    2017-12-31

    Atmospheric carbon dioxide (CO 2 ) concentrations is continuing to increase due to anthropogenic activity, and geological CO 2 storage via carbon capture and storage (CCS) technology can be an effective way to mitigate global warming due to CO 2 emission. However, the possibility of CO 2 leakage from reservoirs and pipelines exists, and such leakage could negatively affect organisms in the soil environment. Therefore, to determine the impacts of geological CO 2 leakage on plant and soil processes, we conducted a greenhouse study in which plants and soils were exposed to high levels of soil CO 2 . Cabbage, which has been reported to be vulnerable to high soil CO 2 , was grown under BI (no injection), NI (99.99% N 2 injection), and CI (99.99% CO 2 injection). Mean soil CO 2 concentration for CI was 66.8-76.9% and the mean O 2 concentrations in NI and CI were 6.6-12.7%, which could be observed in the CO 2 leaked soil from the pipelines connected to the CCS sites. The soil N 2 O emission was increased by 286% in the CI, where NO 3 - -N concentration was 160% higher compared to that in the control. This indicates that higher N 2 O emission from CO 2 leakage could be due to enhanced nitrification process. Higher NO 3 - -N content in soil was related to inhibited plant metabolism. In the CI treatment, chlorophyll content decreased and chlorosis appeared after 8th day of injection. Due to the inhibited root growth, leaf water and nitrogen contents were consistently lowered by 15% under CI treatment. Our results imply that N 2 O emission could be increased by the secondary effects of CO 2 leakage on plant metabolism. Hence, monitoring the environmental changes in rhizosphere would be very useful for impact assessment of CCS technology. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Effect of sodium chloride on photosynthetic 14CO2 assimilation in Portulaca oleracea Linn

    International Nuclear Information System (INIS)

    Joshi, G.V.; Karadge, B.A.

    1979-01-01

    Effect of NaCl on ion uptake, photosynthetic rate and photosynthetic products in a C 4 non-CAM succulent, P. oleracea has been investigated. NaCl causes accumulation of Na as well as Cl ions with decrease in K and Ca contents. Chlorophylls and photosynthetic 14 CO 2 fixation rates are adversely affected due to sodium chloride salinity. Plants grown in the presence of NaCl show increase in C 4 acid percentage with increase in labelling of organic acids in light. Labelling of amino acids (particularly alanine) and sugars (sucrose) is affected by NaCl. Enzyme studies reveal that PEP-carboxylase is stimulated at all concentrations of NaCl but higher concentrations affected the activity of RuBP-Carboxylase. (author)

  6. Elevated CO2 promotes long-term nitrogen accumulation only in combination with nitrogen addition.

    Science.gov (United States)

    Pastore, Melissa A; Megonigal, J Patrick; Langley, J Adam

    2016-01-01

    Biogeochemical models that incorporate nitrogen (N) limitation indicate that N availability will control the magnitude of ecosystem carbon uptake in response to rising CO2 . Some models, however, suggest that elevated CO2 may promote ecosystem N accumulation, a feedback that in the long term could circumvent N limitation of the CO2 response while mitigating N pollution. We tested this prediction using a nine-year CO2 xN experiment in a tidal marsh. Although the effects of CO2 are similar between uplands and wetlands in many respects, this experiment offers a greater likelihood of detecting CO2 effects on N retention on a decadal timescale because tidal marshes have a relatively open N cycle and can accrue soil organic matter rapidly. To determine how elevated CO2 affects N dynamics, we assessed the three primary fates of N in a tidal marsh: (1) retention in plants and soil, (2) denitrification to the atmosphere, and (3) tidal export. We assessed changes in N pools and tracked the fate of a (15) N tracer added to each plot in 2006 to quantify the fraction of added N retained in vegetation and soil, and to estimate lateral N movement. Elevated CO2 alone did not increase plant N mass, soil N mass, or (15) N label retention. Unexpectedly, CO2 and N interacted such that the combined N+CO2 treatment increased ecosystem N accumulation despite the stimulation in N losses indicated by reduced (15) N label retention. These findings suggest that in N-limited ecosystems, elevated CO2 is unlikely to increase long-term N accumulation and circumvent progressive N limitation without additional N inputs, which may relieve plant-microbe competition and allow for increased plant N uptake. © 2015 John Wiley & Sons Ltd.

  7. NIST Photoionization of CO2 (ARPES) Database

    Science.gov (United States)

    SRD 119 NIST Photoionization of CO2 (ARPES) Database (Web, free access)   CO2 is studied using dispersed synchrotron radiation in the 650 Å to 850 Å spectral region. The vibrationally resolved photoelectron spectra are analyzed to generate relative vibrational transition amplitudes and the angular asymmetry parameters describing the various transitions observed.

  8. CO2 Capture with Enzyme Synthetic Analogue

    Energy Technology Data Exchange (ETDEWEB)

    Cordatos, Harry

    2010-11-08

    Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.

  9. Eindhoven Airport : towards zero CO2 emissions

    NARCIS (Netherlands)

    Jorge Simoes Pedro, Joana

    2015-01-01

    Eindhoven airport is growing and it is strongly committed to take this opportunity to invest in innovative solutions for a sustainable development. Therefore, this document proposes a strategic plan for reaching Zero CO2 emissions at Eindhoven airport. This document proposes to reduce the CO2

  10. Thermodynamic modeling of CO2 mixtures

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel

    Knowledge of the thermodynamic properties and phase equilibria of mixtures containing carbon dioxide (CO2) is important in several industrial processes such as enhanced oil recovery, carbon capture and storage, and supercritical extractions, where CO2 is used as a solvent. Despite this importance...

  11. CO2 emission calculations and trends

    International Nuclear Information System (INIS)

    Boden, T.A.; Marland, G.; Andres, R.J.

    1995-01-01

    Evidence that the atmospheric CO 2 concentration has risen during the past several decades is irrefutable. Most of the observed increase in atmospheric CO 2 is believed to result from CO 2 releases from fossil-fuel burning. The United Nations (UN) Framework Convention on Climate Change (FCCC), signed in Rio de Janeiro in June 1992, reflects global concern over the increasing CO 2 concentration and its potential impact on climate. One of the convention's stated objectives was the ''stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. '' Specifically, the FCCC asked all 154 signing countries to conduct an inventory of their current greenhouse gas emissions, and it set nonbinding targets for some countries to control emissions by stabilizing them at 1990 levels by the year 2000. Given the importance of CO 2 as a greenhouse gas, the relationship between CO 2 emissions and increases in atmospheric CO 2 levels, and the potential impacts of a greenhouse gas-induced climate change; it is important that comprehensive CO 2 emissions records be compiled, maintained, updated, and documented

  12. Recent development of capture of CO2

    CERN Document Server

    Chavez, Rosa Hilda

    2014-01-01

    "Recent Technologies in the capture of CO2" provides a comprehensive summary on the latest technologies available to minimize the emission of CO2 from large point sources like fossil-fuel power plants or industrial facilities. This ebook also covers various techniques that could be developed to reduce the amount of CO2 released into the atmosphere. The contents of this book include chapters on oxy-fuel combustion in fluidized beds, gas separation membrane used in post-combustion capture, minimizing energy consumption in CO2 capture processes through process integration, characterization and application of structured packing for CO2 capture, calcium looping technology for CO2 capture and many more. Recent Technologies in capture of CO2 is a valuable resource for graduate students, process engineers and administrative staff looking for real-case analysis of pilot plants. This eBook brings together the research results and professional experiences of the most renowned work groups in the CO2 capture field...

  13. Flow assurance studies for CO2 transport

    NARCIS (Netherlands)

    Veltin, J.; Belfroid, S.P.C.

    2013-01-01

    In order to compensate for the relative lack of experience of the CCTS community, Flow Assurance studies of new CO2 pipelines and networks are a very important step toward reliable operation. This report details a typical approach for Flow Assurance study of CO2 transport pipeline. Considerations to

  14. Phenol-Formaldehyde Resin-Based Carbons for CO2 Separation at Sub-Atmospheric Pressures

    Directory of Open Access Journals (Sweden)

    Noelia Álvarez-Gutiérrez

    2016-03-01

    Full Text Available The challenge of developing effective separation and purification technologies that leave much smaller energy footprints is greater for carbon dioxide (CO2 than for other gases. In addition to its involvement in climate change, CO2 is present as an impurity in biogas and bio-hydrogen (biological production by dark fermentation, in post-combustion processes (flue gas, CO2-N2 and many other gas streams. Selected phenol-formaldehyde resin-based activated carbons prepared in our laboratory have been evaluated under static conditions (adsorption isotherms as potential adsorbents for CO2 separation at sub-atmospheric pressures, i.e., in post-combustion processes or from biogas and bio-hydrogen streams. CO2, H2, N2, and CH4 adsorption isotherms at 25 °C and up to 100 kPa were obtained using a volumetric equipment and were correlated by applying the Sips model. Adsorption equilibrium was then predicted for multicomponent gas mixtures by extending the multicomponent Sips model and the Ideal Adsorbed Solution Theory (IAST in conjunction with the Sips model. The CO2 uptakes of the resin-derived carbons from CO2-CH4, CO2-H2, and CO2-N2 at atmospheric pressure were greater than those of the reference commercial carbon (Calgon BPL. The performance of the resin-derived carbons in terms of equilibrium of adsorption seems therefore relevant to CO2 separation in post-combustion (flue gas, CO2-N2 and in hydrogen fermentation (CO2-H2, CO2-CH4.

  15. A Highly Stable Microporous Covalent Imine Network Adsorbent for Natural Gas Upgrading and Flue Gas CO2 Capture

    KAUST Repository

    Das, Swapan Kumar

    2016-06-06

    The feasible capture and separation of CO2 and N2 from CH4 is an important task for natural gas upgrading and the control of greenhouse gas emissions. Here, we studied the microporous covalent imine networks (CIN) material prepared through Schiff base condensation and exhibited superior chemical robustness under both acidic and basic conditions and high thermal stability. The material possesses a relatively uniform nanoparticle size of approximately 70 to 100 nm. This network featured permanent porosity with a high surface area (722 m2g-1) and micropores. A single-component gas adsorption study showed enhanced CO2 and CH4 uptakes of 3.32 mmol/g and 1.14 mmol/g, respectively, at 273 K and 1 bar, coupled with high separation selectivities for CO2/CH4, CH4/N2, and CO2/N2 of 23, 11.8 and 211, respectively. The enriched Lewis basicity in the porous skeletons favours the interaction of quadrupolar CO2 and polarizable CH4, resulting in enhanced CH4 and CO2 uptake and high CH4/N2, CO2/CH4 and CO2/N2 selectivities. Breakthrough experiments showed high CO2/CH4, CH4/N2 and CO2/N2 selectivities of 7.29, 40 and 125, respectively, at 298 K and 1 bar. High heats of adsorption for CH4 and CO2 (QstCH4; 32.61 kJ mol-1 and QstCO2; 42.42 kJ mol-1) provide the ultimate validation for the high selectivity. To the best of our knowledge, such a versatile adsorbent material that displays both enhanced uptake and selectivity for a variety of binary gas mixtures, including CO2/ CH4, CO2/N2 and CH4/N2, has not been extensively explored.

  16. CO2-ECBM related coupled physical and mechanical transport processes

    Science.gov (United States)

    Gensterblum, Yves; Satorius, Michael; Busch, Andreas; Krooß, Bernhard

    2013-04-01

    The interrelation of cleat transport processes and mechanical properties was investigated by permeability tests at different stress levels (60% to 130% of in-situ stress) with sorbing (CH4, CO2) and inert gases (N2, Ar, He) on a sub bituminous A coal from the Surat Basin, Queensland Australia. From the flow tests under controlled triaxial stress conditions the Klinkenberg-corrected "true" permeability coefficients and the Klinkenberg slip factors were derived. The "true"-, absolute or Klinkenberg corrected permeability shows a gas type dependence. Following the approach of Seidle et al. (1992) the cleat volume compressibility (cf) was calculated from observed changes in apparent permeability upon variation of external stress (at equal mean gas pressures). The observed effects also show a clear dependence on gas type. Due to pore or cleat compressibility the cleat aperture decreases with increasing effective stress. Vice versa we observe with increasing mean pressure at lower confining pressure an increase in permeability which we attribute to a cleat aperture widening. The cleat volume compressibility (cf) also shows a dependence on the mean pore pressure. Non-sorbing gases like helium and argon show higher apparent permeabilities than sorbing gases like methane. Permeability coefficients measured with successively increasing mean gas pressures were consistently lower than those determined at decreasing mean gas pressures. This permeability hysteresis is in accordance with results reported by Harpalani and McPherson (1985). The kinetics of matrix transport processes were studied by sorption tests on different particle sizes at various moisture contents and temperatures (cf. Busch et al., 2006). Methane uptake rates were determined from the pressure decline curves recorded for each particle-size fraction, and "diffusion coefficients" were calculated using several unipore and bidisperse diffusion models. While the CH4 sorption capacity of moisture-equilibrated coals

  17. Development of CO2 circulators

    International Nuclear Information System (INIS)

    Donaldson, J.

    1988-01-01

    The development of the basic machine types we have supplied has not been without problems. The Windscale AGR (the prototype AGR) was a small 1.2 MW vertically up circulator with an inlet temperature of 237 deg. C (459 deg. F). Oil leakage problems occurred and were cured in the works test facility and the machine went into service with no other problems. The Horizontal 5 MW machines for Hinkley/Hunterston were not so fortunate with vibration problems, interface corrosion problems (effecting the whole reactor) and material dimensional stability problems. Oil ingress problems did not show up in test work but were later reported from site. These reports were initially exagerated due to the measuring techniques which took the operators some time to resolve. In the vertical 5 MW machines for Hartlepool and Heysham 1 there are two interesting factors, firstly a spar failure and secondly shaft axial stability. Many of the problems were due to modifications at site or our inability to model all aspects of site installation from which lessons for the future can be learned. The latest stations Torness and Heysham II incorporate these lessons. The machines have been designed with so much margin that during the resolution of the reactor control rod gag problems the machines were run continuously at 20% overload (6.3 MW). From an initial accident case of 350 deg. C inlet temperature, this increased to 458 deg. C and now stands at 585 deg. C. No modifications to the impeller were required. The site experience to date is good with no operational problems reported. (author). 4 figs

  18. Growth strategy of Norway spruce under air elevated [CO2

    Science.gov (United States)

    Pokorny, R.; Urban, O.; Holisova, P.; Sprtova, M.; Sigut, L.; Slipkova, R.

    2012-04-01

    Plants will respond to globally increasing atmospheric CO2 concentration ([CO2]) by acclimation or adaptation at physiological and morphological levels. Considering the temporal onset, physiological responses may be categorized as short-term and morphological ones as long-term responses. The degree of plant growth responses, including cell division and cell expansion, is highly variable. It depends mainly on the specie's genetic predisposition, environment, mineral nutrition status, duration of CO2 enrichment, and/or synergetic effects of other stresses. Elevated [CO2] causes changes in tissue anatomy, quantity, size, shape and spatial orientation and can result in altered sink strength. Since, there are many experimental facilities for the investigation of elevated [CO2] effects on trees: i) closed systems or open top chambers (OTCs), ii) semi-open systems (for example glass domes with adjustable lamella windows - DAWs), and iii) free-air [CO2] enrichments (FACE); the results are still unsatisfactory due to: i) relatively short-term duration of experiments, ii) cultivation of young plants with different growth strategy comparing to old ones, iii) plant cultivation under artificial soil and weather conditions, and iv) in non-representative stand structure. In this contribution we are discussing the physiological and morphological responses of Norway spruce trees cultivated in DAWs during eight consecutive growing seasons in the context with other results from Norway spruce cultivation under air-elevated [CO2] conditions. On the level of physiological responses, we discuss the changes in the rate of CO2 assimilation, assimilation capacity, photorespiration, dark respiration, stomatal conductance, water potential and transpiration, and the sensitivity of these physiological processes to temperature. On the level of morphological responses, we discuss the changes in bud and growth phenology, needle and shoot morphology, architecture of crown and root system, wood

  19. Silvering substrates after CO2 snow cleaning

    Science.gov (United States)

    Zito, Richard R.

    2005-09-01

    There have been some questions in the astronomical community concerning the quality of silver coatings deposited on substrates that have been cleaned with carbon dioxide snow. These questions center around the possible existence of carbonate ions left behind on the substrate by CO2. Such carbonate ions could react with deposited silver to produce insoluble silver carbonate, thereby reducing film adhesion and reflectivity. Carbonate ions could be produced from CO2 via the following mechanism. First, during CO2 snow cleaning, a small amount of moisture can condense on a surface. This is especially true if the jet of CO2 is allowed to dwell on one spot. CO2 gas can dissolve in this moisture, producing carbonic acid, which can undergo two acid dissociations to form carbonate ions. In reality, it is highly unlikely that charged carbonate ions will remain stable on a substrate for very long. As condensed water evaporates, Le Chatelier's principle will shift the equilibrium of the chain of reactions that produced carbonate back to CO2 gas. Furthermore, the hydration of CO2 reaction of CO2 with H20) is an extremely slow process, and the total dehydrogenation of carbonic acid is not favored. Living tissues that must carry out the equilibration of carbonic acid and CO2 use the enzyme carbonic anhydrase to speed up the reaction by a factor of one million. But no such enzymatic action is present on a clean mirror substrate. In short, the worst case analysis presented below shows that the ratio of silver atoms to carbonate radicals must be at least 500 million to one. The results of chemical tests presented here support this view. Furthermore, film lift-off tests, also presented in this report, show that silver film adhesion to fused silica substrates is actually enhanced by CO2 snow cleaning.

  20. The ins and outs of CO2

    Science.gov (United States)

    Raven, John A.; Beardall, John

    2016-01-01

    It is difficult to distinguish influx and efflux of inorganic C in photosynthesizing tissues; this article examines what is known and where there are gaps in knowledge. Irreversible decarboxylases produce CO2, and CO2 is the substrate/product of enzymes that act as carboxylases and decarboxylases. Some irreversible carboxylases use CO2; others use HCO3 –. The relative role of permeation through the lipid bilayer versus movement through CO2-selective membrane proteins in the downhill, non-energized, movement of CO2 is not clear. Passive permeation explains most CO2 entry, including terrestrial and aquatic organisms with C3 physiology and biochemistry, terrestrial C4 plants and all crassulacean acid metabolism (CAM) plants, as well as being part of some mechanisms of HCO3 – use in CO2 concentrating mechanism (CCM) function, although further work is needed to test the mechanism in some cases. However, there is some evidence of active CO2 influx at the plasmalemma of algae. HCO3 – active influx at the plasmalemma underlies all cyanobacterial and some algal CCMs. HCO3 – can also enter some algal chloroplasts, probably as part of a CCM. The high intracellular CO2 and HCO3 – pools consequent upon CCMs result in leakage involving CO2, and occasionally HCO3 –. Leakage from cyanobacterial and microalgal CCMs involves up to half, but sometimes more, of the gross inorganic C entering in the CCM; leakage from terrestrial C4 plants is lower in most environments. Little is known of leakage from other organisms with CCMs, though given the leakage better-examined organisms, leakage occurs and increases the energetic cost of net carbon assimilation. PMID:26466660

  1. Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress.

    Science.gov (United States)

    Pandey, Renu; Zinta, Gaurav; AbdElgawad, Hamada; Ahmad, Altaf; Jain, Vanita; Janssens, Ivan A

    2015-01-01

    Atmospheric [CO2] has increased substantially in recent decades and will continue to do so, whereas the availability of phosphorus (P) is limited and unlikely to increase in the future. P is a non-renewable resource, and it is essential to every form of life. P is a key plant nutrient controlling the responsiveness of photosynthesis to [CO2]. Increases in [CO2] typically results in increased biomass through stimulation of net photosynthesis, and hence enhance the demand for P uptake. However, most soils contain low concentrations of available P. Therefore, low P is one of the major growth-limiting factors for plants in many agricultural and natural ecosystems. The adaptive responses of plants to [CO2] and P availability encompass alterations at morphological, physiological, biochemical and molecular levels. In general low P reduces growth, whereas high [CO2] enhances it particularly in C3 plants. Photosynthetic capacity is often enhanced under high [CO2] with sufficient P supply through modulation of enzyme activities involved in carbon fixation such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). However, high [CO2] with low P availability results in enhanced dry matter partitioning towards roots. Alterations in below-ground processes including root morphology, exudation and mycorrhizal association are influenced by [CO2] and P availability. Under high P availability, elevated [CO2] improves the uptake of P from soil. In contrast, under low P availability, high [CO2] mainly improves the efficiency with which plants produce biomass per unit P. At molecular level, the spatio-temporal regulation of genes involved in plant adaptation to low P and high [CO2] has been studied individually in various plant species. Genome-wide expression profiling of high [CO2] grown plants revealed hormonal regulation of biomass accumulation through complex transcriptional networks. Similarly, differential transcriptional regulatory networks are involved in P

  2. Dynamic flow method to study the CO2 loading capacity of amino acid salt solutions

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

    Due to a number of advantages amino acid salt solutions have emerged as alternatives to the alkanolamine solvents for the chemical absorption of CO2 from flue gas. The use of amino acids in CO2 capture is a bio-mimetic process, as it is similar to CO2 binding by proteins in the blood......, such as hemoglobin. Amino acid salt solutions have the same amine functionality as alkanolamines, and are thus expected to behave similar towards CO2 in flue gas. Despite rising interest, few studies have been performed so far on amino acids as CO2 absorbents....

  3. Cyanobacterial carbon concentrating mechanisms facilitate sustained CO2 depletion in eutrophic lakes

    Directory of Open Access Journals (Sweden)

    A. M. Morales-Williams

    2017-06-01

    Full Text Available Phytoplankton blooms are increasing in frequency, intensity, and duration in aquatic ecosystems worldwide. In many eutrophic lakes, these high levels of primary productivity correspond to periods of CO2 depletion in surface waters. Cyanobacteria and other groups of phytoplankton have the ability to actively transport bicarbonate (HCO3− across their cell membrane when CO2 concentrations are limiting, possibly giving them a competitive advantage over algae not using carbon concentrating mechanisms (CCMs. To investigate whether CCMs can maintain phytoplankton bloom biomass under CO2 depletion, we measured the δ13C signatures of dissolved inorganic carbon (δ13CDIC and phytoplankton particulate organic carbon (δ13Cphyto in 16 mesotrophic to hypereutrophic lakes during the ice-free season of 2012. We used mass–balance relationships to determine the dominant inorganic carbon species used by phytoplankton under CO2 stress. We found a significant positive relationship between phytoplankton biomass and phytoplankton δ13C signatures as well as a significant nonlinear negative relationship between water column ρCO2 and isotopic composition of phytoplankton, indicating a shift from diffusive uptake to active uptake by phytoplankton of CO2 or HCO3− during blooms. Calculated photosynthetic fractionation factors indicated that this shift occurs specifically when surface water CO2 drops below atmospheric equilibrium. Our results indicate that active HCO3− uptake via CCMs may be an important mechanism in maintaining phytoplankton blooms when CO2 is depleted. Further increases in anthropogenic pressure, eutrophication, and cyanobacteria blooms are therefore expected to contribute to increased bicarbonate uptake to sustain primary production.

  4. Cyanobacterial carbon concentrating mechanisms facilitate sustained CO2 depletion in eutrophic lakes

    Science.gov (United States)

    Morales-Williams, Ana M.; Wanamaker, Alan D., Jr.; Downing, John A.

    2017-06-01

    Phytoplankton blooms are increasing in frequency, intensity, and duration in aquatic ecosystems worldwide. In many eutrophic lakes, these high levels of primary productivity correspond to periods of CO2 depletion in surface waters. Cyanobacteria and other groups of phytoplankton have the ability to actively transport bicarbonate (HCO3-) across their cell membrane when CO2 concentrations are limiting, possibly giving them a competitive advantage over algae not using carbon concentrating mechanisms (CCMs). To investigate whether CCMs can maintain phytoplankton bloom biomass under CO2 depletion, we measured the δ13C signatures of dissolved inorganic carbon (δ13CDIC) and phytoplankton particulate organic carbon (δ13Cphyto) in 16 mesotrophic to hypereutrophic lakes during the ice-free season of 2012. We used mass-balance relationships to determine the dominant inorganic carbon species used by phytoplankton under CO2 stress. We found a significant positive relationship between phytoplankton biomass and phytoplankton δ13C signatures as well as a significant nonlinear negative relationship between water column ρCO2 and isotopic composition of phytoplankton, indicating a shift from diffusive uptake to active uptake by phytoplankton of CO2 or HCO3- during blooms. Calculated photosynthetic fractionation factors indicated that this shift occurs specifically when surface water CO2 drops below atmospheric equilibrium. Our results indicate that active HCO3- uptake via CCMs may be an important mechanism in maintaining phytoplankton blooms when CO2 is depleted. Further increases in anthropogenic pressure, eutrophication, and cyanobacteria blooms are therefore expected to contribute to increased bicarbonate uptake to sustain primary production.

  5. STABILITY OF CO2 ATMOSPHERES ON DESICCATED M DWARF EXOPLANETS

    International Nuclear Information System (INIS)

    Gao, Peter; Hu, Renyu; Li, Cheng; Yung, Yuk L.; Robinson, Tyler D.

    2015-01-01

    We investigate the chemical stability of CO 2 -dominated atmospheres of desiccated M dwarf terrestrial exoplanets using a one-dimensional photochemical model. Around Sun-like stars, CO 2 photolysis by Far-UV (FUV) radiation is balanced by recombination reactions that depend on water abundance. Planets orbiting M dwarf stars experience more FUV radiation, and could be depleted in water due to M dwarfs’ prolonged, high-luminosity pre-main sequences. We show that, for water-depleted M dwarf terrestrial planets, a catalytic cycle relying on H 2 O 2 photolysis can maintain a CO 2 atmosphere. However, this cycle breaks down for atmospheric hydrogen mixing ratios <1 ppm, resulting in ∼40% of the atmospheric CO 2 being converted to CO and O 2 on a timescale of 1 Myr. The increased O 2 abundance leads to high O 3 concentrations, the photolysis of which forms another CO 2 -regenerating catalytic cycle. For atmospheres with <0.1 ppm hydrogen, CO 2 is produced directly from the recombination of CO and O. These catalytic cycles place an upper limit of ∼50% on the amount of CO 2 that can be destroyed via photolysis, which is enough to generate Earth-like abundances of (abiotic) O 2 and O 3 . The conditions that lead to such high oxygen levels could be widespread on planets in the habitable zones of M dwarfs. Discrimination between biological and abiotic O 2 and O 3 in this case can perhaps be accomplished by noting the lack of water features in the reflectance and emission spectra of these planets, which necessitates observations at wavelengths longer than 0.95 μm

  6. Limitations to CO2-induced growth enhancement in pot studies.

    Science.gov (United States)

    McConnaughay, K D M; Berntson, G M; Bazzaz, F A

    1993-07-01

    Recently, it has been suggested that small pots may reduce or eliminate plant responses to enriched CO 2 atmospheres due to root restriction. While smaller pot volumes provide less physical space available for root growth, they also provide less nutrients. Reduced nutrient availability alone may reduce growth enhancement under elevated CO 2 . To investigate the relative importance of limited physical rooting space separate from and in conjunction with soil nutrients, we grew plants at ambient and double-ambient CO 2 levels in growth containers of varied volume, shape, nutrient concentration, and total nutrient content. Two species (Abutilon theophrasti, a C 3 dicot with a deep tap root andSetaria faberii, a C 4 monocot with a shallow diffuse root system) were selected for their contrasting physiology and root architecture. Shoot demography was determined weekly and biomass was determined after eight and ten weeks of growth. Increasing total nutrients, either by increasing nutrient concentration or by increasing pot size, increased plant growth. Further, increasing pot size while maintaining equal total nutrients per pot resulted in increased total biomass for both species. CO 2 -induced growth and reproductive yield enhancements were greatest in pots with high nutrient concentrations, regardless of total nutrient content or pot size, and were also mediated by the shape of the pot. CO 2 -induced growth and reproductive yield enhancements were unaffected by pot size (growth) or were greater in small pots (reproductive yield), regardless of total nutrient content, contrary to predictions based on earlier studies. These results suggest that several aspects of growth conditions within pots may influence the CO 2 responses of plants; pot size, pot shape, the concentration and total amount of nutrient additions to pots may lead to over-or underestimates of the CO 2 responses of real-world plants.

  7. Tracing the link between plant volatile organic compound emissions and CO2 fluxes and by stable isotopes

    Science.gov (United States)

    Werner, Christiane; Wegener, Frederik; Jardine, Kolby

    2015-04-01

    The vegetation exerts a large influence on the atmosphere through the emission of volatile organic compounds (VOCs) and the emission and uptake of the greenhouse gas CO2. Despite the enormous importance, processes controlling plant carbon allocation into primary and secondary metabolism, such as photosynthetic carbon uptake, respiratory CO2 emission and VOC synthesis, remains unclear. Moreover, vegetation-atmosphere CO2 exchange is associated with a large isotopic imprint due to photosynthetic carbon isotope discrimination and 13C-fractionation during respiratory CO2 release1. The latter has been proposed to be related to carbon partitioning in the metabolic branching points of the respiratory pathways and secondary metabolism, which are linked via a number of interfaces including the central metabolite pyruvate. Notably, it is a known substrate in a large array of secondary pathways leading to the biosynthesis of many volatile organic compounds (VOCs), such as volatile isoprenoids, oxygenated VOCs, aromatics, fatty acid oxidation products, which can be emitted by plants. Here we investigate the linkage between VOC emissions, CO2 fluxes and associated isotope effects based on simultaneous real-time measurements of stable carbon isotope composition of branch respired CO2 (CRDS) and VOC fluxes (PTR-MS). We utilized positionally specific 13C-labeled pyruvate branch feeding experiments in the mediterranean shrub (Halimium halimifolium) to trace the partitioning of C1, C2, and C3 carbon atoms of pyruvate into VOCs versus CO2 emissions in the light and in the dark. In the light, we found high emission rates of a large array of VOC including volatile isoprenoids, oxygenated VOCs, green leaf volatiles, aromatics, sulfides, and nitrogen containing VOCs. These observations suggest that in the light, H. halimifolium dedicates a high carbon flux through secondary biosynthetic pathways including the pyruvate dehydrogenase bypass, mevalonic acid, MEP/DOXP, shikimic acid, and

  8. Effects of a holiday week on urban soil CO2 flux: an intensive study in Xiamen, southeastern China

    Science.gov (United States)

    Ye, H.; Wang, K.; Chen, F.

    2012-12-01

    To study the effects of a holiday period on urban soil CO2 flux, CO2 efflux from grassland soil in a traditional park in the city of Xiamen was measured hourly from 28th Sep to 11th Oct, a period that included China's National Day holiday week in 2009. The results of this study revealed that: a) The urban soil CO2 emissions were higher before and after the holiday week and lower during the National Day holiday reflecting changes in the traffic cycles; b) A diurnal cycle where the soil CO2 flux decreased from early morning to noon was associated with CO2 uptake by vegetation which strongly offset vehicle CO2 emissions. The soil CO2 flux increased from night to early morning, associated with reduced CO2 uptake by vegetation; c) During the National Day holiday week in 2009, lower rates of soil respiration were measured after Mid-Autumn Day than earlier in the week, and this was related to a reduced level of human activities and vehicle traffic, reducing the CO2 concentration in the air. Urban holidays have a clear effect on soil CO2 flux through the interactions between vehicle, visitor and vegetation CO2 emissions which indirectly control the use of carbon by plant roots, the rhizosphere and soil microorganisms. Consequently, appropriate traffic controls and tourism travel plans can have positive effects on the soil carbon store and may improve local air quality.

  9. Neptunium(V) sorption onto kaolinite in the absence and presence of CO2

    International Nuclear Information System (INIS)

    Amayri, S.; Reich, Ta.; Reich, T.

    2005-01-01

    Full text of publication follows: The adsorption of heavy metals on clay minerals such as kaolinite is an important process that affects the migration and retardation of neptunium and other actinides in the geosphere. The sorption of Np(V) onto the reference clay mineral kaolinite KGa-1b was investigated both by batch experiments and EXAFS measurements. The aim of our study was to combine macroscopic studies (batch experiments) with microscopic techniques (EXAFS) to study the Np(V) speciation at the kaolinite surface. The batch experiments were done under relevant environmental conditions with Np(V) concentrations of 10 -11 and 10 -12 mol/L. Sorption samples were prepared in 0.1 mol/L NaClO 4 , 4 g/L kaolinite, pH 6.0 to 10.5, presence and absence of ambient CO 2 , and 60-h equilibration. The sorption curves for 10 -11 and 10 -12 mol/L Np(V) obtained in the presence and absence of CO 2 , respectively, show that the adsorption edge occurs at pH 8.5. The uptake of Np(V) by kaolinite strongly increased above pH 7.0 and reached its sorption maximum (70 %) at pH 9.0. Above pH 9.0, the amount of Np(V) sorbed onto kaolinite decreased and reached ca. 30 % at pH 10.5 due to the formation of Np(V) carbonato species in the aqueous solution. In the CO 2 -free system, the sorption of Np(V) increased continuously with pH until the sorption maximum of 100 % was reached at pH 10.5. The same sorption behavior was found in batch experiments in the CO 2 equilibrated system with Np concentrations ranging from 1 μmol/L to 10 μmol/L. EXAFS experiments on some of these batch samples indicated the formation of Np(V) carbonato species at the kaolinite surface at pH 9.0 where the uptake of Np(V) by kaolinite reaches its maximum [1]. [1] T. Reich, S. Amayri, Ta. Reich, J. Drebert, A. Jermolajev, P. Thoerle, N. Trautmann, C. Hennig, S. Sachs, Feasibility of EXAFS experiments at the Np L-edge to investigate neptunium sorption on kaolinite, Institut fuer Kernchemie, Universitaet Mainz, Annual

  10. NiCo2O4-Based Supercapacitor Nanomaterials

    Directory of Open Access Journals (Sweden)

    Chenggang Wang

    2017-02-01

    Full Text Available In recent years, the research on supercapacitors has ushered in an explosive growth, which mainly focuses on seeking nano-/micro-materials with high energy and power densities. Herein, this review will be arranged from three aspects. We will summarize the controllable architectures of spinel NiCo2O4 fabricated by various approaches. Then, we introduce their performances as supercapacitors due to their excellent electrochemical performance, including superior electronic conductivity and electrochemical activity, together with the low cost and environmental friendliness. Finally, the review will be concluded with the perspectives on the future development of spinel NiCo2O4 utilized as the supercapacitor electrodes.

  11. NiCo2O4-Based Supercapacitor Nanomaterials

    Science.gov (United States)

    Wang, Chenggang; Zhou, E; He, Weidong; Deng, Xiaolong; Huang, Jinzhao; Ding, Meng; Wei, Xianqi; Liu, Xiaojing; Xu, Xijin

    2017-01-01

    In recent years, the research on supercapacitors has ushered in an explosive growth, which mainly focuses on seeking nano-/micro-materials with high energy and power densities. Herein, this review will be arranged from three aspects. We will summarize the controllable architectures of spinel NiCo2O4 fabricated by various approaches. Then, we introduce their performances as supercapacitors due to their excellent electrochemical performance, including superior electronic conductivity and electrochemical activity, together with the low cost and environmental friendliness. Finally, the review will be concluded with the perspectives on the future development of spinel NiCo2O4 utilized as the supercapacitor electrodes. PMID:28336875

  12. Modelling CO2-Brine Interfacial Tension using Density Gradient Theory

    KAUST Repository

    Ruslan, Mohd Fuad Anwari Che

    2018-03-01

    Knowledge regarding carbon dioxide (CO2)-brine interfacial tension (IFT) is important for petroleum industry and Carbon Capture and Storage (CCS) strategies. In petroleum industry, CO2-brine IFT is especially importance for CO2 – based enhanced oil recovery strategy as it affects phase behavior and fluid transport in porous media. CCS which involves storing CO2 in geological storage sites also requires understanding regarding CO2-brine IFT as this parameter affects CO2 quantity that could be securely stored in the storage site. Several methods have been used to compute CO2-brine interfacial tension. One of the methods employed is by using Density Gradient Theory (DGT) approach. In DGT model, IFT is computed based on the component density distribution across the interface. However, current model is only applicable for modelling low to medium ionic strength solution. This limitation is due to the model only considers the increase of IFT due to the changes of bulk phases properties and does not account for ion distribution at interface. In this study, a new modelling strategy to compute CO2-brine IFT based on DGT was proposed. In the proposed model, ion distribution across interface was accounted for by separating the interface to two sections. The saddle point of tangent plane distance where ( ) was defined as the boundary separating the two sections of the interface. Electrolyte is assumed to be present only in the second section which is connected to the bulk liquid phase side. Numerical simulations were performed using the proposed approach for single and mixed salt solutions for three salts (NaCl, KCl, and CaCl2), for temperature (298 K to 443 K), pressure (2 MPa to 70 MPa), and ionic strength (0.085 mol·kg-1 to 15 mol·kg-1). The simulation result shows that the tuned model was able to predict with good accuracy CO2-brine IFT for all studied cases. Comparison with current DGT model showed that the proposed approach yields better match with the experiment data

  13. Recycling CO 2 ? Computational Considerations of the Activation of CO 2 with Homogeneous Transition Metal Catalysts

    KAUST Repository

    Drees, Markus; Cokoja, Mirza; Kü hn, Fritz E.

    2012-01-01

    . A similar approach, storing energy from renewable sources in chemical bonds with CO 2 as starting material, may lead to partial recycling of CO 2 created by human industrial activities. Unfortunately, currently available routes for the transformation

  14. Potential and economics of CO2 sequestration

    International Nuclear Information System (INIS)

    Jean-Baptiste, Ph.; Ciais, Ph.; Orr, J.

    2001-01-01

    Increasing atmospheric level of greenhouse gases are causing global warming and putting at risk the global climate system. The main anthropogenic greenhouse gas is CO 2 . Some techniques could be used to reduced CO 2 emission and stabilize atmospheric CO 2 concentration, including i) energy savings and energy efficiency, ii) switch to lower carbon content fuels (natural gas) and use energy sources with zero CO 2 emissions such as renewable or nuclear energy, iii) capture and store CO 2 from fossil fuels combustion, and enhance the natural sinks for CO 2 (forests, soils, ocean...). The purpose of this report is to provide an overview of the technology and cost for capture and storage of CO 2 and to review the various options for CO 2 sequestration by enhancing natural carbon sinks. Some of the factors which will influence application, including environmental impact, cost and efficiency, are discussed. Capturing CO 2 and storing it in underground geological reservoirs appears as the best environmentally acceptable option. It can be done with existing technology, however, substantial R and D is needed to improve available technology and to lower the cost. Applicable to large CO 2 emitting industrial facilities such as power plants, cement factories, steel industry, etc., which amount to about 30% of the global anthropic CO 2 emission, it represents a valuable tool in the baffle against global warming. About 50% of the anthropic CO 2 is being naturally absorbed by the biosphere and the ocean. The 'natural assistance' provided by these two large carbon reservoirs to the mitigation of climate change is substantial. The existing natural sinks could be enhanced by deliberate action. Given the known and likely environmental consequences, which could be very damaging indeed, enhancing ocean sinks does not appears as a satisfactory option. In contrast, the promotion of land sinks through demonstrated carbon-storing approach to agriculture, forests and land management could

  15. A microporous MOF with a polar pore surface exhibiting excellent selective adsorption of CO2 from CO2-N2 and CO2-CH4 gas mixtures with high CO2 loading.

    Science.gov (United States)

    Pal, Arun; Chand, Santanu; Elahi, Syed Meheboob; Das, Madhab C

    2017-11-14

    A microporous MOF {[Zn(SDB)(L) 0.5 ]·S} n (IITKGP-5) with a polar pore surface has been constructed by the combination of a V-shaped -SO 2 functionalized organic linker (H 2 SDB = 4,4'-sulfonyldibenzoic acid) with an N-rich spacer (L = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene), forming a network with sql(2,6L1) topology. IITKGP-5 is characterized by TGA, PXRD and single crystal X-ray diffraction. The framework exhibits lozenge-shaped channels of an approximate size of 4.2 × 5.6 Å 2 along the crystallographic b axis with a potential solvent accessible volume of 26%. The activated IITKGP-5a revealed a CO 2 uptake capacity of 56.4 and 49 cm 3 g -1 at 273 K/1 atm and 295 K/1 atm, respectively. On the contrary, it takes up a much smaller amount of CH 4 (17 cm 3 g -1 at 273 K and 13.6 cm 3 g -1 at 295 K) and N 2 (5.5 cm 3 g -1 at 273 K; 4 cm 3 g -1 at 295 K) under 1 atm pressure exhibiting its potential for a highly selective adsorption of CO 2 from flue gas as well as a landfill gas mixture. Based on the ideal adsorbed solution theory (IAST), a CO 2 /N 2 selectivity of 435.5 and a CO 2 /CH 4 selectivity of 151.6 have been realized at 273 K/100 kPa. The values at 295 K are 147.8 for CO 2 /N 2 and 23.8 for CO 2 /CH 4 gas mixtures under 100 kPa. In addition, this MOF nearly approaches the target values proposed for PSA and TSA processes for practical utility exhibiting its prospect for flue gas separation with a CO 2 loading capacity of 2.04 mmol g -1 .

  16. The effect of hydrate promoters on gas uptake.

    Science.gov (United States)

    Xu, Chun-Gang; Yu, Yi-Song; Ding, Ya-Long; Cai, Jing; Li, Xiao-Sen

    2017-08-16

    Gas hydrate technology is considered as a promising technology in the fields of gas storage and transportation, gas separation and purification, seawater desalination, and phase-change thermal energy storage. However, to date, the technology is still not commercially used mainly due to the low gas hydrate formation rate and the low gas uptake. In this study, the effect of hydrate promoters on gas uptake was systematically studied and analyzed based on hydrate-based CH 4 storage and CO 2 capture from CO 2 /H 2 gas mixture experiments. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC) were employed to analyze the microstructures and gas compositions. The results indicate that the effect of the hydrate promoter on the gas uptake depends on the physical and chemical properties of the promoter and gas. A strong polar ionic promoter is not helpful towards obtaining the ideal gas uptake because a dense hydrate layer is easily formed at the gas-liquid interface, which hinders gas diffusion from the gas phase to the bulk solution. For a weak polar or non-polar promoter, the gas uptake depends on the dissolution characteristics among the different substances in the system. The lower the mutual solubility among the substances co-existing in the system, the higher the independence among the substances in the system; this is so that each phase has an equal chance to occupy the hydrate cages without or with small interactions, finally leading to a relatively high gas uptake.

  17. High net CO2 and CH4 release at a eutrophic shallow lake on a formerly drained fen

    Science.gov (United States)

    Franz, Daniela; Koebsch, Franziska; Larmanou, Eric; Augustin, Jürgen; Sachs, Torsten

    2016-05-01

    Drained peatlands often act as carbon dioxide (CO2) hotspots. Raising the groundwater table is expected to reduce their CO2 contribution to the atmosphere and revitalise their function as carbon (C) sink in the long term. Without strict water management rewetting often results in partial flooding and the formation of spatially heterogeneous, nutrient-rich shallow lakes. Uncertainties remain as to when the intended effect of rewetting is achieved, as this specific ecosystem type has hardly been investigated in terms of greenhouse gas (GHG) exchange. In most cases of rewetting, methane (CH4) emissions increase under anoxic conditions due to a higher water table and in terms of global warming potential (GWP) outperform the shift towards CO2 uptake, at least in the short term.Based on eddy covariance measurements we studied the ecosystem-atmosphere exchange of CH4 and CO2 at a shallow lake situated on a former fen grassland in northeastern Germany. The lake evolved shortly after flooding, 9 years previous to our investigation period. The ecosystem consists of two main surface types: open water (inhabited by submerged and floating vegetation) and emergent vegetation (particularly including the eulittoral zone of the lake, dominated by Typha latifolia). To determine the individual contribution of the two main surface types to the net CO2 and CH4 exchange of the whole lake ecosystem, we combined footprint analysis with CH4 modelling and net ecosystem exchange partitioning.The CH4 and CO2 dynamics were strikingly different between open water and emergent vegetation. Net CH4 emissions from the open water area were around 4-fold higher than from emergent vegetation stands, accounting for 53 and 13 g CH4 m-2 a-1 respectively. In addition, both surface types were net CO2 sources with 158 and 750 g CO2 m-2 a-1 respectively. Unusual meteorological conditions in terms of a warm and dry summer and a mild winter might have facilitated high respiration rates. In sum, even after 9

  18. The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance

    Science.gov (United States)

    Connell, Sean D.; Kroeker, Kristy J.; Fabricius, Katharina E.; Kline, David I.; Russell, Bayden D.

    2013-01-01

    Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO2) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO2 on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO2] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO2 experiments and data from ‘natural’ volcanic CO2 vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO2 conditions both in temperate and tropical conditions. The benefits of CO2 are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO2 world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO2 as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects. PMID:23980244

  19. Photosynthetic response to globally increasing CO2 of co-occurring temperate seagrass species.

    Science.gov (United States)

    Borum, Jens; Pedersen, Ole; Kotula, Lukasz; Fraser, Matthew W; Statton, John; Colmer, Timothy D; Kendrick, Gary A

    2016-06-01

    Photosynthesis of most seagrass species seems to be limited by present concentrations of dissolved inorganic carbon (DIC). Therefore, the ongoing increase in atmospheric CO2 could enhance seagrass photosynthesis and internal O2 supply, and potentially change species competition through differential responses to increasing CO2 availability among species. We used short-term photosynthetic responses of nine seagrass species from the south-west of Australia to test species-specific responses to enhanced CO2 and changes in HCO3 (-) . Net photosynthesis of all species except Zostera polychlamys were limited at pre-industrial compared to saturating CO2 levels at light saturation, suggesting that enhanced CO2 availability will enhance seagrass performance. Seven out of the nine species were efficient HCO3 (-) users through acidification of diffusive boundary layers, production of extracellular carbonic anhydrase, or uptake and internal conversion of HCO3 (-) . Species responded differently to near saturating CO2 implying that increasing atmospheric CO2 may change competition among seagrass species if co-occurring in mixed beds. Increasing CO2 availability also enhanced internal aeration in the one species assessed. We expect that future increases in atmospheric CO2 will have the strongest impact on seagrass recruits and sparsely vegetated beds, because densely vegetated seagrass beds are most often limited by light and not by inorganic carbon. © 2015 John Wiley & Sons Ltd.

  20. The other ocean acidification problem: CO2 as a resource among competitors for ecosystem dominance.

    Science.gov (United States)

    Connell, Sean D; Kroeker, Kristy J; Fabricius, Katharina E; Kline, David I; Russell, Bayden D

    2013-01-01

    Predictions concerning the consequences of the oceanic uptake of increasing atmospheric carbon dioxide (CO2) have been primarily occupied with the effects of ocean acidification on calcifying organisms, particularly those critical to the formation of habitats (e.g. coral reefs) or their maintenance (e.g. grazing echinoderms). This focus overlooks direct and indirect effects of CO2 on non-calcareous taxa that play critical roles in ecosystem shifts (e.g. competitors). We present the model that future atmospheric [CO2] may act as a resource for mat-forming algae, a diverse and widespread group known to reduce the resilience of kelp forests and coral reefs. We test this hypothesis by combining laboratory and field CO2 experiments and data from 'natural' volcanic CO2 vents. We show that mats have enhanced productivity in experiments and more expansive covers in situ under projected near-future CO2 conditions both in temperate and tropical conditions. The benefits of CO2 are likely to vary among species of producers, potentially leading to shifts in species dominance in a high CO2 world. We explore how ocean acidification combines with other environmental changes across a number of scales, and raise awareness of CO2 as a resource whose change in availability could have wide-ranging community consequences beyond its direct effects.

  1. Study of the synthesis and self-assembly of CO2-philic copolymers with complexing groups: application to decontamination in supercritical CO2 medium

    International Nuclear Information System (INIS)

    Ribaut, T.

    2009-10-01

    In the frame of sustainable development, a priority is to decrease the volume of nuclear wastes. The use of supercritical carbon dioxide (scCO 2 ) could allow to solve this problem. The aim of this study is to extract an ionic or particle cobalt contamination deposited on textile lab coats. The strategy uses CO 2 -philic/CO 2 -phobic copolymers soluble in scCO 2 and containing complexing groups. This approach combines the use of amphiphilic copolymers for steric stabilization of particles, of surfactants able to self-assemble to promote extraction and of ligands. Controlled radical polymerization is used to synthesize fluorinated gradient or block copolymers. Cloud point curves of the copolymers are determined experimentally in scCO 2 . Prediction of polymer/scCO 2 phase diagrams was assessed by Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) modeling. Gradient copolymers appear more advantageous than block copolymers due to their solubility in much milder conditions of pressure and temperature. Small-angle neutron scattering (SANS) allowed us to evidence the pressure-induced aggregation of the gradient copolymers in scCO 2 . Their interface properties were demonstrated: they allow to form water-in-CO 2 microemulsions and to stabilize cobalt hydroxide dispersions in scCO 2 . Lastly, in presence of a very low quantity of water, Co 2+ ions were removed with a rate of 37 % from a cotton/polyester matrix by a gradient copolymer. (author)

  2. Measurements and modeling of absorption by CO2 + H2O mixtures in the spectral region beyond the CO2 ν3-band head

    Science.gov (United States)

    Tran, H.; Turbet, M.; Chelin, P.; Landsheere, X.

    2018-05-01

    In this work, we measured the absorption by CO2 + H2O mixtures from 2400 to 2600 cm-1 which corresponds to the spectral region beyond the ν3 band head of CO2. Transmission spectra of CO2 mixed with water vapor were recorded with a high-resolution Fourier-transform spectrometer for various pressure, temperature and concentration conditions. The continuum absorption by CO2 due to the presence of water vapor was determined by subtracting from measured spectra the contribution of local lines of both species, that of the continuum of pure CO2 as well as of the self- and CO2-continua of water vapor induced by the H2O-H2O and H2O-CO2 interactions. The obtained results are in very good agreement with the unique previous measurement (in a narrower spectral range). They confirm that the H2O-continuum of CO2 is significantly larger than that observed for pure CO2. This continuum thus must be taken into account in radiative transfer calculations for media involving CO2+ H2O mixture. An empirical model, using sub-Lorentzian line shapes based on some temperature-dependent correction factors χ is proposed which enables an accurate description of the experimental results.

  3. The water-water cycle in leaves is not a major alternative electron sink for dissipation of excess excitation energy when CO2 assimilation is restricted

    NARCIS (Netherlands)

    Driever, S.M.; Baker, N.R.

    2011-01-01

    Electron flux from water via photosystem II (PSII) and PSI to oxygen (water–water cycle) may provide a mechanism for dissipation of excess excitation energy in leaves when CO2 assimilation is restricted. Mass spectrometry was used to measure O2 uptake and evolution together with CO2 uptake in leaves

  4. Performance evaluation of integrated trigeneration and CO2 refrigeration systems

    International Nuclear Information System (INIS)

    Suamir, IN.; Tassou, S.A.

    2013-01-01

    Food retailing is one of the most energy intensive sectors of the food cold chain. Its environmental impacts are significant not only because of the indirect effect from CO 2 emissions at the power stations but also due to the direct effect arising from refrigerant leakage to the atmosphere. The overall energy efficiency of supermarkets can be increased by integrating the operation of CO 2 refrigeration and trigeneration systems. This paper compares three alternative schemes in a medium size supermarket. Experimental results and simulation studies have shown that the best scheme for energy and GHG emissions savings is the one where the cooling produced by the trigeneration system is used to condense the CO 2 fluid in the refrigeration system to ensure subcritical operation throughout the year. It is shown that this system can produce 30% energy savings and over 40% greenhouse gas emissions savings over conventional refrigeration and indoor environment control systems in supermarkets.

  5. Electrocatalytic Alloys for CO2 Reduction.

    Science.gov (United States)

    He, Jingfu; Johnson, Noah J J; Huang, Aoxue; Berlinguette, Curtis P

    2018-01-10

    Electrochemically reducing CO 2 using renewable energy is a contemporary global challenge that will only be met with electrocatalysts capable of efficiently converting CO 2 into fuels and chemicals with high selectivity. Although many different metals and morphologies have been tested for CO 2 electrocatalysis over the last several decades, relatively limited attention has been committed to the study of alloys for this application. Alloying is a promising method to tailor the geometric and electric environments of active sites. The parameter space for discovering new alloys for CO 2 electrocatalysis is particularly large because of the myriad products that can be formed during CO 2 reduction. In this Minireview, mixed-metal electrocatalyst compositions that have been evaluated for CO 2 reduction are summarized. A distillation of the structure-property relationships gleaned from this survey are intended to help in the construction of guidelines for discovering new classes of alloys for the CO 2 reduction reaction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. CO_2 capture by amine-functionalized nanoporous materials: A review

    International Nuclear Information System (INIS)

    Chen, Chao; Kim, Jun; Ahn, Wha-Seung

    2014-01-01

    Amine-functionalized nanoporous materials can be prepared by the incorporation of diverse organic amine moieties into the pore structures of a range of support materials, such as mesoporous silica and alumina, zeolite, carbon and metal organic frameworks (MOFs), either by direct functionalization or post-synthesis through physical impregnation or grafting. These hybrid materials have great potential for practical applications, such as dry adsorbents for postcombustion CO_2 capture, owing to their high CO_2 capture capacity, high capture selectivity towards CO_2 compared to other gases, and excellent stability. This paper summarizes the preparation methods and CO_2 capture performance based on the equilibrium CO_2 uptake of a range of amine-functionalized nanoporous materials

  7. Soil warming enhances the hidden shift of elemental stoichiometry by elevated CO2 in wheat

    DEFF Research Database (Denmark)

    Li, Xiangnan; Jiang, Dong; Liu, Fulai

    2016-01-01

    sap and their partitioning in different organs of wheat plant during grain filling were investigated. Results showed that the combination of elevated [CO2] and soil warming improved wheat grain yield, but decreased plant K, Ca and Mg accumulation and their concentrations in the leaves, stems, roots......Increase in atmospheric CO2 concentration ([CO2]) and associated soil warming along with global climate change are expected to have large impacts on grain mineral nutrition in wheat. The effects of CO2 elevation (700 μmol l(-1)) and soil warming (+2.4 °C) on K, Ca and Mg concentrations in the xylem...... and grains. The reduced grain mineral concentration was attributed to the lowered mineral uptake as exemplified by both the decreased stomatal conductance and mineral concentration in the xylem sap. These findings suggest that future higher atmospheric [CO2] and warmer soil conditions may decrease...

  8. Soil CO2 flux in response to elevated atmospheric CO2 and nitrogen fertilization: patterns and methods

    Science.gov (United States)

    James M. Vose; Katherine J. Elliott; D.W. Johnson

    1995-01-01

    The evolution of carbon dioxide (CO2) from soils is due to the metabolic activity of roots, mycorrhizae, and soil micro- and macro-organisms. Although precise estimates of carbon (C) recycled to the atmosphere from belowground sources are unavailable, Musselman and Fox (1991) propose that the belowground contribution exceeds 100 Pg y-1...

  9. CO2 Accounting and Risk Analysis for CO2 Sequestration at Enhanced Oil Recovery Sites.

    Science.gov (United States)

    Dai, Zhenxue; Viswanathan, Hari; Middleton, Richard; Pan, Feng; Ampomah, William; Yang, Changbing; Jia, Wei; Xiao, Ting; Lee, Si-Yong; McPherson, Brian; Balch, Robert; Grigg, Reid; White, Mark

    2016-07-19

    Using CO2 in enhanced oil recovery (CO2-EOR) is a promising technology for emissions management because CO2-EOR can dramatically reduce sequestration costs in the absence of emissions policies that include incentives for carbon capture and storage. This study develops a multiscale statistical framework to perform CO2 accounting and risk analysis in an EOR environment at the Farnsworth Unit (FWU), Texas. A set of geostatistical-based Monte Carlo simulations of CO2-oil/gas-water flow and transport in the Morrow formation are conducted for global sensitivity and statistical analysis of the major risk metrics: CO2/water injection/production rates, cumulative net CO2 storage, cumulative oil/gas productions, and CO2 breakthrough time. The median and confidence intervals are estimated for quantifying uncertainty ranges of the risk metrics. A response-surface-based economic model has been derived to calculate the CO2-EOR profitability for the FWU site with a current oil price, which suggests that approximately 31% of the 1000 realizations can be profitable. If government carbon-tax credits are available, or the oil price goes up or CO2 capture and operating expenses reduce, more realizations would be profitable. The results from this study provide valuable insights for understanding CO2 storage potential and the corresponding environmental and economic risks of commercial-scale CO2-sequestration in depleted reservoirs.

  10. Effects of tillage practice and atmospheric CO2 level on soil CO2 efflux

    Science.gov (United States)

    Elevated atmospheric carbon dioxide (CO2) affects both the quantity and quality of plant tissues, which impacts the cycling and storage of carbon (C) within plant/soil systems and thus the rate of CO2 release back to the atmosphere. Research to accurately quantify the effects of elevated CO2 and as...

  11. Estimating CO2 Emission Reduction of Non-capture CO2 Utilization (NCCU) Technology

    International Nuclear Information System (INIS)

    Lee, Ji Hyun; Lee, Dong Woog; Gyu, Jang Se; Kwak, No-Sang; Lee, In Young; Jang, Kyung Ryoung; Shim, Jae-Goo; Choi, Jong Shin

    2015-01-01

    Estimating potential of CO 2 emission reduction of non-capture CO 2 utilization (NCCU) technology was evaluated. NCCU is sodium bicarbonate production technology through the carbonation reaction of CO 2 contained in the flue gas. For the estimating the CO 2 emission reduction, process simulation using process simulator (PRO/II) based on a chemical plant which could handle CO 2 of 100 tons per day was performed, Also for the estimation of the indirect CO 2 reduction, the solvay process which is a conventional technology for the production of sodium carbonate/sodium bicarbonate, was studied. The results of the analysis showed that in case of the solvay process, overall CO 2 emission was estimated as 48,862 ton per year based on the energy consumption for the production of NaHCO 3 (7.4 GJ/tNaHCO 3 ). While for the NCCU technology, the direct CO 2 reduction through the CO 2 carbonation was estimated as 36,500 ton per year and the indirect CO 2 reduction through the lower energy consumption was 46,885 ton per year which lead to 83,385 ton per year in total. From these results, it could be concluded that sodium bicarbonate production technology through the carbonation reaction of CO 2 contained in the flue was energy efficient and could be one of the promising technology for the low CO 2 emission technology.

  12. Drought stress and tree size determine stem CO2 efflux in a tropical forest.

    Science.gov (United States)

    Rowland, Lucy; da Costa, Antonio C L; Oliveira, Alex A R; Oliveira, Rafael S; Bittencourt, Paulo L; Costa, Patricia B; Giles, Andre L; Sosa, Azul I; Coughlin, Ingrid; Godlee, John L; Vasconcelos, Steel S; Junior, João A S; Ferreira, Leandro V; Mencuccini, Maurizio; Meir, Patrick

    2018-06-01

    CO 2 efflux from stems (CO 2_stem ) accounts for a substantial fraction of tropical forest gross primary productivity, but the climate sensitivity of this flux remains poorly understood. We present a study of tropical forest CO 2_stem from 215 trees across wet and dry seasons, at the world's longest running tropical forest drought experiment site. We show a 27% increase in wet season CO 2_stem in the droughted forest relative to a control forest. This was driven by increasing CO 2_stem in trees 10-40 cm diameter. Furthermore, we show that drought increases the proportion of maintenance to growth respiration in trees > 20 cm diameter, including large increases in maintenance respiration in the largest droughted trees, > 40 cm diameter. However, we found no clear taxonomic influence on CO 2_stem and were unable to accurately predict how drought sensitivity altered ecosystem scale CO 2_stem , due to substantial uncertainty introduced by contrasting methods previously employed to scale CO 2_stem fluxes. Our findings indicate that under future scenarios of elevated drought, increases in CO 2_stem may augment carbon losses, weakening or potentially reversing the tropical forest carbon sink. However, due to substantial uncertainties in scaling CO 2_stem fluxes, stand-scale future estimates of changes in stem CO 2 emissions remain highly uncertain. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

  13. Have We Overestimated Saline Aquifer CO2 Storage Capacities?

    International Nuclear Information System (INIS)

    Thibeau, S.; Mucha, V.

    2011-01-01

    During future, large scale CO 2 geological storage in saline aquifers, fluid pressure is expected to rise as a consequence of CO 2 injection, but the pressure build up will have to stay below specified values to ensure a safe and long term containment of the CO 2 in the storage site. The pressure build up is the result of two different effects. The first effect is a local overpressure around the injectors, which is due to the high CO 2 velocities around the injectors, and which can be mitigated by adding CO 2 injectors. The second effect is a regional scale pressure build up that will take place if the storage aquifer is closed or if the formation water that flows away from the pressurised area is not large enough to compensate volumetrically the CO 2 injection. This second effect cannot be mitigated by adding additional injectors. In the first section of this paper, we review some major global and regional assessments of CO 2 storage capacities in deep saline aquifers, in term of mass and storage efficiency. These storage capacities are primarily based on a volumetric approach: storage capacity is the volumetric sum of the CO 2 that can be stored through various trapping mechanisms. We then discuss in Section 2 storage efficiencies derived from a pressure build up approach, as stated in the CO2STORE final report (Chadwick A. et al. (eds) (2008) Best Practice for the Storage of CO 2 in Saline Aquifers, Observations and Guidelines from the SACS and CO2STORE Projects, Keyworth, Nottingham, BGS Occasional Publication No. 14) and detailed by Van der Meer and Egberts (van der Meer L.G.H., Egberts P.J.P. (2008) A General Method for Calculating Subsurface CO 2 Storage Capacity, OTC Paper 19309, presented at the OTC Conference held in Houston, Texas, USA, 5-8 May). A quantitative range of such storage efficiency is presented, based on a review of orders of magnitudes of pore and water compressibilities and allowable pressure increase. To illustrate the relevance of this

  14. CO2 content of electricity losses

    International Nuclear Information System (INIS)

    Daví-Arderius, Daniel; Sanin, María-Eugenia; Trujillo-Baute, Elisa

    2017-01-01

    Countries are implementing policies to develop greener energy markets worldwide. In Europe, the ¨2030 Energy and Climate Package¨ asks for further reductions of green house gases, renewable sources integration, and energy efficiency targets. But the polluting intensity of electricity may be different in average than when considering market inefficiencies, in particular losses, and therefore the implemented policy must take those differences into account. Precisely, herein we study the importance in terms of CO2 emissions the extra amount of energy necessary to cover losses. With this purpose we use Spanish market and system data with hourly frequency from 2011 to 2013. Our results show that indeed electricity losses significantly explain CO2 emissions, with a higher CO2 emissions rate when covering losses than the average rate of the system. Additionally, we find that the market closing technologies used to cover losses have a positive and significant impact on CO2 emissions: when polluting technologies (coal or combined cycle) close the market, the impact of losses on CO2 emissions is high compared to the rest of technologies (combined heat and power, renewables or hydropower). To the light of these results we make some policy recommendations to reduce the impact of losses on CO2 emissions. - Highlights: • Electricity losses significantly explain CO2 emissions. • Policies aimed to reducing losses have a positive impact on CO2 emissions. • The market closing technology used to cover losses have impacts on CO2 emissions. • Pollutant technologies that close the market should be replaced by renewables.

  15. CO2 fluxes near a forest edge

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Leclerc, Monique Y.; Zhang, Gensheng

    2008-01-01

    In contrast with recent advances on the dynamics of the flow at a forest edge, few studies have considered its role on scalar transport and, in particular, on CO2 transfer. The present study addresses the influence of the abrupt roughness change on forest atmosphere CO2 exchange and contrasts...... as a function of both sources/sinks distribution and the vertical structure of the canopy. Results suggest that the ground source plays a major role in the formation of wave-like vertical CO2 flux behavior downwind of a forest edge, despite the fact that the contribution of foliage sources/sinks changes...

  16. CO2, the promises of geological sequestration

    International Nuclear Information System (INIS)

    Rouat, S.

    2006-01-01

    Trapping part of the world CO 2 effluents in the deep underground is a profitable and ecological way to limit the global warming. This digest paper presents the different ways of CO 2 sequestration (depleted oil and gas fields, unexploited coal seams, saline aquifers), the other possible solutions for CO 2 abatement (injection in the bottom of the ocean, conversion into carbonates by injection into basic rocks, fixation by photosynthesis thanks to micro-algae cultivation), and takes stock of the experiments in progress (Snoehvit field in Norway, European project Castor). (J.S.)

  17. Climate change and the CO2 myth

    International Nuclear Information System (INIS)

    Boettcher, C.J.F.

    1994-01-01

    Further increase of the CO 2 concentration in the atmosphere has little effect on the greenhouse effect contrary to the effect of the increase of other greenhouse gases. However, politicians are using targets for the reduction of CO 2 emissions that are unrealistic, taking into account the scientific uncertainties of the applied models, the doubts about the feasibility of quantitative targets and the economic consequences of such drastic measures. Some recommendations are given for a more realistic CO 2 policy. Also attention is paid to the important role that coal will play in the future of the energy supply. 5 figs., 3 ills

  18. CO2 Emission Reduction in Energy Sector

    International Nuclear Information System (INIS)

    Bole, A.; Sustersic, A.; Voncina, R.

    2013-01-01

    Due to human activities, concentrations of the greenhouse gases increase in the atmosphere much quicker than they naturally would. Today it is clear that climate change is the result of human activities. With the purpose of preventing, reducing and mitigating of climate change, the EU, whose member is also Slovenia, set ambitious goals. In order to keep rise of the global atmosphere temperature below 2 degrees of C, the European Council set an objective of reducing greenhouse gas emissions by 80 - 95 % by 2050 compared to 1990. It is important that every single individual is included in achieving of these goals. Certainly, the most important role is assumed by individual sectors especially Public Electricity and Heat Production sector as one of the greatest emitters of the greenhouse gases. As a possible solution of radical reduction of the greenhouse gases emission from mentioned sector Carbon Capture and Storage (CCS) technology is implemented. In the article the range of CO 2 reduction possibilities, technology demands and environmental side effects of CCS technology are described. Evaluation of CCS implementation possibilities in Slovenia is also included.(author)

  19. Responses of pink salmon to CO2-induced aquatic acidification

    Science.gov (United States)

    Ou, Michelle; Hamilton, Trevor J.; Eom, Junho; Lyall, Emily M.; Gallup, Joshua; Jiang, Amy; Lee, Jason; Close, David A.; Yun, Sang-Seon; Brauner, Colin J.

    2015-10-01

    Ocean acidification negatively affects many marine species and is predicted to cause widespread changes to marine ecosystems. Similarly, freshwater ecosystems may potentially be affected by climate-change-related acidification; however, this has received far less attention. Freshwater fish represent 40% of all fishes, and salmon, which rear and spawn in freshwater, are of immense ecosystem, economical and cultural importance. In this study, we investigate the impacts of CO2-induced acidification during the development of pink salmon, in freshwater and following early seawater entry. At this critical and sensitive life stage, we show dose-dependent reductions in growth, yolk-to-tissue conversion and maximal O2 uptake capacity; as well as significant alterations in olfactory responses, anti-predator behaviour and anxiety under projected future increases in CO2 levels. These data indicate that future populations of pink salmon may be at risk without mitigation and highlight the need for further studies on the impact of CO2-induced acidification on freshwater systems.

  20. Rising CO2 levels will intensify phytoplankton blooms in eutrophic and hypertrophic lakes.

    Directory of Open Access Journals (Sweden)

    Jolanda M H Verspagen

    Full Text Available Harmful algal blooms threaten the water quality of many eutrophic and hypertrophic lakes and cause severe ecological and economic damage worldwide. Dense blooms often deplete the dissolved CO2 concentration and raise pH. Yet, quantitative prediction of the feedbacks between phytoplankton growth, CO2 drawdown and the inorganic carbon chemistry of aquatic ecosystems has received surprisingly little attention. Here, we develop a mathematical model to predict dynamic changes in dissolved inorganic carbon (DIC, pH and alkalinity during phytoplankton bloom development. We tested the model in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa at different CO2 levels. The experiments showed that dense blooms sequestered large amounts of atmospheric CO2, not only by their own biomass production but also by inducing a high pH and alkalinity that enhanced the capacity for DIC storage in the system. We used the model to explore how phytoplankton blooms of eutrophic waters will respond to rising CO2 levels. The model predicts that (1 dense phytoplankton blooms in low- and moderately alkaline waters can deplete the dissolved CO2 concentration to limiting levels and raise the pH over a relatively wide range of atmospheric CO2 conditions, (2 rising atmospheric CO2 levels will enhance phytoplankton blooms in low- and moderately alkaline waters with high nutrient loads, and (3 above some threshold, rising atmospheric CO2 will alleviate phytoplankton blooms from carbon limitation, resulting in less intense CO2 depletion and a lesser increase in pH. Sensitivity analysis indicated that the model predictions were qualitatively robust. Quantitatively, the predictions were sensitive to variation in lake depth, DIC input and CO2 gas transfer across the air-water interface, but relatively robust to variation in the carbon uptake mechanisms of phytoplankton. In total, these findings warn that rising CO2 levels may result in a marked

  1. Rising CO2 Levels Will Intensify Phytoplankton Blooms in Eutrophic and Hypertrophic Lakes

    Science.gov (United States)

    Verspagen, Jolanda M. H.; Van de Waal, Dedmer B.; Finke, Jan F.; Visser, Petra M.; Van Donk, Ellen; Huisman, Jef

    2014-01-01

    Harmful algal blooms threaten the water quality of many eutrophic and hypertrophic lakes and cause severe ecological and economic damage worldwide. Dense blooms often deplete the dissolved CO2 concentration and raise pH. Yet, quantitative prediction of the feedbacks between phytoplankton growth, CO2 drawdown and the inorganic carbon chemistry of aquatic ecosystems has received surprisingly little attention. Here, we develop a mathematical model to predict dynamic changes in dissolved inorganic carbon (DIC), pH and alkalinity during phytoplankton bloom development. We tested the model in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa at different CO2 levels. The experiments showed that dense blooms sequestered large amounts of atmospheric CO2, not only by their own biomass production but also by inducing a high pH and alkalinity that enhanced the capacity for DIC storage in the system. We used the model to explore how phytoplankton blooms of eutrophic waters will respond to rising CO2 levels. The model predicts that (1) dense phytoplankton blooms in low- and moderately alkaline waters can deplete the dissolved CO2 concentration to limiting levels and raise the pH over a relatively wide range of atmospheric CO2 conditions, (2) rising atmospheric CO2 levels will enhance phytoplankton blooms in low- and moderately alkaline waters with high nutrient loads, and (3) above some threshold, rising atmospheric CO2 will alleviate phytoplankton blooms from carbon limitation, resulting in less intense CO2 depletion and a lesser increase in pH. Sensitivity analysis indicated that the model predictions were qualitatively robust. Quantitatively, the predictions were sensitive to variation in lake depth, DIC input and CO2 gas transfer across the air-water interface, but relatively robust to variation in the carbon uptake mechanisms of phytoplankton. In total, these findings warn that rising CO2 levels may result in a marked intensification of

  2. A Biomimetic Nickel Complex with a Reduced CO2 Ligand Generated by Formate Deprotonation and its Behaviour towards CO2.

    Science.gov (United States)

    Limberg, Christian; Zimmermann, Philipp; Hoof, Santina; Braun-Cula, Beatrice; Herwig, Christian

    2018-04-10

    Reduced CO2 species are key intermediates in a variety of natural and synthetic processes. In the majority of systems, however, they elude isolation or characterisation due to high reactivity or limited accessibility (heterogeneous systems) and thus formulations often remain uncertain or based on calculations only. We herein report on a Ni-CO22- complex that is unique in many ways. While its structural and electronic features help understanding the CO2 bound state in Ni,Fe carbon monoxide dehydrogenases, its reactivity sheds light on how CO2 can be converted into CO/CO32- by nickel complexes. In addition, the complex has been generated via a rare example of formate β deprotonation, a mechanistical step relevant to nickel catalysed conversion of HxCOyz- at electrodes and formate oxidation in formate dehydrogenases. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Equilibration of metabolic CO2 with preformed CO2 and bicarbonate

    International Nuclear Information System (INIS)

    Hems, R.; Saez, G.T.

    1983-01-01

    Entry of metabolic 14 CO 2 into urea is shown to occur more readily than it equilibrates with the general pool of cellular plus extracellular bicarbonate plus CO 2 . Since the sites of CO 2 production (pyruvate dehydrogenase and oxoglutarate dehydrogenase) and of fixation (carbamoylphosphate synthetase) are intramitochondrial, it is likely that the fixation of CO 2 is also more rapid than its equilibration with the cytoplasmic pool of bicarbonate plus CO 2 . This observation may point to a more general problem concerning the interpretation of isotope data, with compartmentation or proximity of sites of production and utilisation of metabolites may result in the isotope following a preferred pathway. (Auth.)

  4. Carbon recycling by cyanobacteria: improving CO2 fixation through chemical production.

    Science.gov (United States)

    Zhang, Angela; Carroll, Austin L; Atsumi, Shota

    2017-09-01

    Atmospheric CO2 levels have reached an alarming level due to industrialization and the burning of fossil fuels. In order to lower the level of atmospheric carbon, strategies to sequester excess carbon need to be implemented. The CO2-fixing mechanism in photosynthetic organisms enables integration of atmospheric CO2 into biomass. Additionally, through exogenous metabolic pathways in these photosynthetic organisms, fixed CO2 can be routed to produce various commodity chemicals that are currently produced from petroleum. This review will highlight studies and modifications to different components of cyanobacterial CO2-fixing systems, as well as the application of these systems toward CO2-derived chemical production. 2,3-Butanediol is given particular focus as one of the most thoroughly studied systems for conversion of CO2 to a bioproduct. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Development of Double and Triple-Pulsed 2-micron IPDA Lidars for Column CO2 Measurements

    Science.gov (United States)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Reithmaier, Karl

    2015-01-01

    Carbon dioxide (CO2) is an important greenhouse gas that significantly contributes to the carbon cycle and globalradiation budget on Earth. CO2 role on Earth’s climate is complicated due to different interactions with various climatecomponents that include the atmosphere, the biosphere and the hydrosphere. Although extensive worldwide efforts formonitoring atmospheric CO2 through various techniques, including in-situ and passive sensors, are taking place highuncertainties exist in quantifying CO2 sources and sinks. These uncertainties are mainly due to insufficient spatial andtemporal mapping of the gas. Therefore it is required to have more rapid and accurate CO2 monitoring with higheruniform coverage and higher resolution. CO2 DIAL operating in the 2-µm band offer better near-surface CO2measurement sensitivity due to the intrinsically stronger absorption lines. For more than 15 years, NASA LangleyResearch Center (LaRC) contributed in developing several 2-?m CO2 DIAL systems and technologies. This paperfocuses on the current development of the airborne double-pulsed and triple-pulsed 2-?m CO2 integrated pathdifferential absorption (IPDA) lidar system at NASA LaRC. This includes the IPDA system development andintegration. Results from ground and airborne CO2 IPDA testing will be presented. The potential of scaling suchtechnology to a space mission will be addressed.

  6. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used...... as the sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone...... that raw meal could be used as a sorbent for the easy integration of the carbonate looping process into the cement pyro process for reducing CO2 emissions from the cement production process....

  7. Energy Efficiency instead of CO2 levy

    International Nuclear Information System (INIS)

    Uetz, R.

    2005-01-01

    This article takes a look at ways of avoiding a future, planned Swiss CO 2 levy by improving the efficiency of energy use. The political situation concerning the reduction of CO 2 emissions in Switzerland is reviewed and the likeliness of the introduction of a CO 2 levy is discussed. Strategies for the reduction of fossil fuel consumption and therefore of CO 2 emissions are looked at, including process optimisation. Recommendations are made on how to approach this work systematically - data collection, assessment of the potential for reduction and the planning of measures to be taken are looked at. The high economic efficiency of immediate action is stressed and typical middle and long-term measures are listed

  8. The ATLAS IBL CO2 Cooling System

    CERN Document Server

    Verlaat, Bartholomeus; The ATLAS collaboration

    2016-01-01

    The Atlas Pixel detector has been equipped with an extra B-layer in the space obtained by a reduced beam pipe. This new pixel detector called the ATLAS Insertable B-Layer (IBL) is installed in 2014 and is operational in the current ATLAS data taking. The IBL detector is cooled with evaporative CO2 and is the first of its kind in ATLAS. The ATLAS IBL CO2 cooling system is designed for lower temperature operation (<-35⁰C) than the previous developed CO2 cooling systems in High Energy Physics experiments. The cold temperatures are required to protect the pixel sensors for the high expected radiation dose up to 550 fb^-1 integrated luminosity. This paper describes the design, development, construction and commissioning of the IBL CO2 cooling system. It describes the challenges overcome and the important lessons learned for the development of future systems which are now under design for the Phase-II upgrade detectors.

  9. Capture and geological storage of CO2

    International Nuclear Information System (INIS)

    2013-03-01

    Capture and geological storage of CO 2 could be a contribution to reduce CO 2 emissions, and also a way to meet the factor 4 objective of reduction of greenhouse gas emissions. This publication briefly presents the capture and storage definitions and principles, and comments some key data related to CO 2 emissions, and their natural trapping by oceans, soils and forests. It discusses strengths (a massive and perennial reduction of CO 2 emissions, a well defined regulatory framework) and weaknesses (high costs and uncertain cost reduction perspectives, a technology which still consumes a lot of energy, geological storage capacities still to be determined, health environmental impacts and risks to be controlled, a necessary consultation of population for planned projects) of this option. Actions undertaken by the ADEME are briefly reviewed

  10. CO2 Washout Capability with Breathing Manikin

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon Dioxide (CO2) Washout performance is a critical parameter needed to ensure proper and sufficient designs in a spacesuit and in vehicle applications such as...

  11. Upscaling of enzyme enhanced CO2 capture

    DEFF Research Database (Denmark)

    Gladis, Arne Berthold

    Fossil fuels are the backbone of the energy generation in the coming decades for USA, China, India and Europe, hence high greenhouse gas emissions are expected in future. Carbon capture and storage technology (CCS) is the only technology that can mitigate greenhouse gas emissions from fossil fuel...... the mass transfer of CO2 with slow-capturing but energetically favorable solvents can open up a variety of new process options for this technology. The ubiquitous enzyme carbonic anhydrase (CA), which enhances the mass transfer of CO2 in the lungs by catalyzing the reversible hydration of CO2, is one very...... enhanced CO2 capture technology by identifying the potentials and limitations in lab and in pilot scale and benchmarking the process against proven technologies. The main goal was to derive a realistic process model for technical size absorbers with a wide range of validity incorporating a mechanistic...

  12. A database for CO2 Separation Performances of MOFs based on Computational Materials Screening.

    Science.gov (United States)

    Altintas, Cigdem; Avci, Gokay; Daglar, Hilal; Nemati Vesali Azar, Ayda; Velioglu, Sadiye; Erucar, Ilknur; Keskin, Seda

    2018-05-03

    Metal organic frameworks (MOFs) have been considered as great candidates for CO2 capture. Considering the very large number of available MOFs, high-throughput computational screening plays a critical role in identifying the top performing materials for target applications in a time-effective manner. In this work, we used molecular simulations to screen the most recent and complete MOF database for identifying the most promising materials for CO2 separation from flue gas (CO2/N2) and landfill gas (CO2/CH4) under realistic operating conditions. We first validated our approach by comparing the results of our molecular simulations for the CO2 uptakes, CO2/N2 and CO2/CH4 selectivities of various types of MOFs with the available experimental data. We then computed binary CO2/N2 and CO2/CH4 mixture adsorption data for the entire MOF database and used these results to calculate several adsorbent selection metrics such as selectivity, working capacity, adsorbent performance score, regenerability, and separation potential. MOFs were ranked based on the combination of these metrics and the top performing MOF adsorbents that can achieve CO2/N2 and CO2/CH4 separations with high performance were identified. Molecular simulations for the adsorption of a ternary CO2/N2/CH4 mixture were performed for these top materials in order to provide a more realistic performance assessment of MOF adsorbents. Structure-performance analysis showed that MOFs with ΔQ>30 kJ/mol, 3.8 A≤PLD≤5 A, 5 A≤LCD≤7.5 A, 0.5≤ϕ≤0.75, SA≤1,000 m2/g, ρ>1 g/cm 3 are the best candidates for selective separation of CO2 from flue gas and landfill gas. This information will be very useful to design novel MOFs with the desired structural features that can lead to high CO2 separation potentials. Finally, an online, freely accessible database https://cosmoserc.ku.edu.tr was established, for the first time in the literature, which reports all computed adsorbent metrics of 3,816 MOFs for CO2/N2, CO2/CH4

  13. Root damage by insects reverses the effects of elevated atmospheric CO2 on Eucalypt seedlings.

    Directory of Open Access Journals (Sweden)

    Scott N Johnson

    Full Text Available Predicted increases in atmospheric carbon dioxide (CO2 are widely anticipated to increase biomass accumulation by accelerating rates of photosynthesis in many plant taxa. Little, however, is known about how soil-borne plant antagonists might modify the effects of elevated CO2 (eCO2, with root-feeding insects being particularly understudied. Root damage by insects often reduces rates of photosynthesis by disrupting root function and imposing water deficits. These insects therefore have considerable potential for modifying plant responses to eCO2. We investigated how root damage by a soil-dwelling insect (Xylotrupes gideon australicus modified the responses of Eucalyptus globulus to eCO2. eCO2 increased plant height when E. globulus were 14 weeks old and continued to do so at an accelerated rate compared to those grown at ambient CO2 (aCO2. Plants exposed to root-damaging insects showed a rapid decline in growth rates thereafter. In eCO2, shoot and root biomass increased by 46 and 35%, respectively, in insect-free plants but these effects were arrested when soil-dwelling insects were present so that plants were the same size as those grown at aCO2. Specific leaf mass increased by 29% under eCO2, but at eCO2 root damage caused it to decline by 16%, similar to values seen in plants at aCO2 without root damage. Leaf C:N ratio increased by >30% at eCO2 as a consequence of declining leaf N concentrations, but this change was also moderated by soil insects. Soil insects also reduced leaf water content by 9% at eCO2, which potentially arose through impaired water uptake by the roots. We hypothesise that this may have impaired photosynthetic activity to the extent that observed plant responses to eCO2 no longer occurred. In conclusion, soil-dwelling insects could modify plant responses to eCO2 predicted by climate change plant growth models.

  14. Performance of supercritical Brayton cycle using CO2-based binary mixture at varying critical points for SFR applications

    International Nuclear Information System (INIS)

    Jeong, Woo Seok; Jeong, Yong Hoon

    2013-01-01

    Highlights: • Supercritical CO 2 -based gas mixture Brayton cycles were investigated for a SFR. • The critical point of CO 2 is the lowest cycle operating limit of the S-CO 2 cycles. • Mixing additives with CO 2 changes the CO 2 critical point. • CO 2 –Xe and CO 2 –Kr cycles achieve higher cycle efficiencies than the S-CO 2 cycles. • CO 2 –H 2 S and CO 2 –cyclohexane cycles perform better at higher heat sink temperatures. -- Abstract: The supercritical carbon dioxide Brayton cycle (S-CO 2 cycle) has attracted much attention as an alternative to the Rankine cycle for sodium-cooled fast reactors (SFRs). The higher cycle efficiency of the S-CO 2 cycle results from the considerably decreased compressor work because the compressor behaves as a pump in the proximity of the CO 2 vapor–liquid critical point. In order to fully utilize this feature, the main compressor inlet condition should be controlled to be close to the critical point of CO 2 . This indicates that the critical point of CO 2 is a constraint on the minimum cycle condition for S-CO 2 cycles. Modifying the CO 2 critical point by mixing additive gases could be considered as a method of enhancing the performance and broadening the applicability of the S-CO 2 cycle. Due to the drastic fluctuations of the thermo-physical properties of fluids near the critical point, an in-house cycle analysis code using the NIST REFPROP database was implemented. Several gases were selected as potential additives considering their thermal stability and chemical interaction with sodium in the temperature range of interest and the availability of the mixture property database: xenon, krypton, hydrogen sulfide, and cyclohexane. The performances of the optimized CO 2 -containing binary mixture cycles with simple recuperated and recompression layouts were compared with the reference S-CO 2 , CO 2 –Ar, CO 2 –N 2 , and CO 2 –O 2 cycles. For the decreased critical temperatures, the CO 2 –Xe and CO 2

  15. CO2 emissions of nuclear power supply

    International Nuclear Information System (INIS)

    Wissel, S.; Mayer-Spohn, O.; Fahl, U.; Voss, A.

    2007-01-01

    Increasingly, supported by the recent reports of the IPCC (International Panel on Climate Change), political, social and scientific institutions call for the use of atomic energy for reducing CO2 emissions. In Germany, the discussion is highly controversial. A life-cycle balance of nuclear power shows that its CO2 emissions are much lower than those of other technologies, even if changes in the nuclear fuel cycle are taken into account. (orig.)

  16. Photoacoustic CO2-Sensor for Automotive Applications

    OpenAIRE

    Huber, J.; Weber, C.; Eberhardt, A.; Wöllenstein, J.

    2016-01-01

    We present a field-tested miniaturized spectroscopic CO2 sensor which is based on the photoacoustic effect. The sensor is developed for automotive applications and considers the requirements for the usage in vehicles. The sensor measures two measurement ranges simultaneously: The monitoring of the indoor air quality and the detection of possible leakages of the coolant in CO2 air-conditioning systems. The sensor consists of a miniaturized innovative photoacoustic sensor unit with integrated e...

  17. Study on CO2 global recycling system

    International Nuclear Information System (INIS)

    Takeuchi, M.; Sakamoto, Y.; Niwa, S.

    2001-01-01

    In order to assist in finding ways to mitigate CO 2 emission and to slow the depletion of fossil fuels we have established and evaluated a representative system, which consists of three technologies developed in our laboratory. These technologies were in CO 2 recovery, hydrogen production and methanol synthesis and in addition we established the necessary supporting systems. Analysis of outline designs of the large scale renewable energy power generation system and this system and energy input for building plant, energy input for running plant has been conducted based on a case using this system for a 1000-MW coal fired power plant, followed by an evaluation of the material balance and energy balance. The results are as follows. Energy efficiency is 34%, the CO 2 reduction rate is 41%, the balance ratio of the energy and CO 2 of the system is 2.2 and 1.8, respectively, on the assumption that the primary renewable energy is solar thermal power generation, the stationary CO 2 emission source is a coal-fired power plant and the generation efficiency of the methanol power plant is 60%. By adopting the system, 3.7 million tons of CO 2 can be recovered, approximately 2.7 million tons of methanol can be produced, and 15.4 billion kWh of electricity can be generated per year. Compared to generating all electrical power using only coal, approximately 2.6 million tons of coal per year can be saved and approximately 2.15 million tons of CO 2 emission can be reduced. Therefore, it is clearly revealed that this system would be effective to reduce CO 2 emissions and to utilize renewable energy

  18. Anthropogenic CO2 in the ocean

    Directory of Open Access Journals (Sweden)

    Tsung-Hung Peng

    2005-06-01

    Full Text Available The focus of this review article is on the anthropogenic CO2 taken up by the ocean. There are several methods of identifying the anthropogenic CO2 signal and quantifying its inventory in the ocean. The ?C* method is most frequently used to estimate the global distribution of anthropogenic CO2 in the ocean. Results based on analysis of the dataset obtained from the comprehensive surveys of inorganic carbon distribution in the world oceans in the 1990s are given. These surveys were jointly conducted during the World Ocean Circulation Experiment (WOCE and the Joint Global Ocean Flux Study (JGOFS. This data set consists of 9618 hydrographic stations from a total of 95 cruises, which represents the most accurate and comprehensive view of the distribution of inorganic carbon in the global ocean available today. The increase of anthropogenic CO2 in the ocean during the past few decades is also evaluated using direct comparison of results from repeat surveys and using statistical method of Multi-parameter Linear Regression (MLR. The impact of increasing oceanic anthropogenic CO2 on the calcium carbonate system in the ocean is reviewed briefly as well. Extensive studies of CaCO3 dissolution as a result of increasing anthropogenic CO2 in the ocean have revealed several distinct oceanic regions where the CaCO3 undersaturation zone has expanded.

  19. CO2 efflux from cleared mangrove peat.

    Directory of Open Access Journals (Sweden)

    Catherine E Lovelock

    Full Text Available CO(2 emissions from cleared mangrove areas may be substantial, increasing the costs of continued losses of these ecosystems, particularly in mangroves that have highly organic soils.We measured CO(2 efflux from mangrove soils that had been cleared for up to 20 years on the islands of Twin Cays, Belize. We also disturbed these cleared peat soils to assess what disturbance of soils after clearing may have on CO(2 efflux. CO(2 efflux from soils declines from time of clearing from ∼10,600 tonnes km(-2 year(-1 in the first year to 3000 tonnes km(2 year(-1 after 20 years since clearing. Disturbing peat leads to short term increases in CO(2 efflux (27 umol m(-2 s(-1, but this had returned to baseline levels within 2 days.Deforesting mangroves that grow on peat soils results in CO(2 emissions that are comparable to rates estimated for peat collapse in other tropical ecosystems. Preventing deforestation presents an opportunity for countries to benefit from carbon payments for preservation of threatened carbon stocks.

  20. Synthesis of Hierarchically Structured Hybrid Materials by Controlled Self-Assembly of Metal-Organic Framework with Mesoporous Silica for CO2 Adsorption.

    Science.gov (United States)

    Chen, Chong; Li, Bingxue; Zhou, Lijin; Xia, Zefeng; Feng, Nengjie; Ding, Jing; Wang, Lei; Wan, Hui; Guan, Guofeng

    2017-07-12

    The HKUST-1@SBA-15 composites with hierarchical pore structure were constructed by in situ self-assembly of metal-organic framework (MOF) with mesoporous silica. The structure directing role of SBA-15 had an obvious impact on the growth of MOF crystals, which in turn affected the morphologies and structural properties of the composites. The pristine HKUST-1 and the composites with different content of SBA-15 were characterized by XRD, N 2 adsorption-desorption, SEM, TEM, FT-IR, TG, XPS, and CO 2 -TPD techniques. It was found that the composites were assembled by oriented growth of MOF nanocrystals on the surfaces of SBA-15 matrix. The interactions between surface silanol groups and metal centers induced structural changes and resulted in the increases in surface areas as well as micropore volumes of hybrid materials. Besides, the additional constraints from SBA-15 also restrained the expansion of HKUST-1, contributing to their smaller crystal sizes in the composites. The adsorption isotherms of CO 2 on the materials were measured and applied to calculate the isosteric heats of adsorption. The HS-1 composite exhibited an increase of 15.9% in CO 2 uptake capacity compared with that of HKUST-1. Moreover, its higher isosteric heats of CO 2 adsorption indicated the stronger interactions between the surfaces and CO 2 molecules. The adsorption rate of the composite was also improved due to the introduction of mesopores. Ten cycles of CO 2 adsorption-desorption experiments implied that the HS-1 had excellent reversibility of CO 2 adsorption. This study was intended to provide the possibility of assembling new composites with tailored properties based on MOF and mesoporous silica to satisfy the requirements of various applications.

  1. How secure is subsurface CO2 storage? Controls on leakage in natural CO2 reservoirs

    Science.gov (United States)

    Miocic, Johannes; Gilfillan, Stuart; McDermott, Christopher; Haszeldine, Stuart

    2014-05-01

    Carbon Capture and Storage (CCS) is the only industrial scale technology available to directly reduce carbon dioxide (CO2) emissions from fossil fuelled power plants and large industrial point sources to the atmosphere. The technology includes the capture of CO2 at the source and transport to subsurface storage sites, such as depleted hydrocarbon reservoirs or saline aquifers, where it is injected and stored for long periods of time. To have an impact on the greenhouse gas emissions it is crucial that there is no or only a very low amount of leakage of CO2 from the storage sites to shallow aquifers or the surface. CO2 occurs naturally in reservoirs in the subsurface and has often been stored for millions of years without any leakage incidents. However, in some cases CO2 migrates from the reservoir to the surface. Both leaking and non-leaking natural CO2 reservoirs offer insights into the long-term behaviour of CO2 in the subsurface and on the mechanisms that lead to either leakage or retention of CO2. Here we present the results of a study on leakage mechanisms of natural CO2 reservoirs worldwide. We compiled a global dataset of 49 well described natural CO2 reservoirs of which six are leaking CO2 to the surface, 40 retain CO2 in the subsurface and for three reservoirs the evidence is inconclusive. Likelihood of leakage of CO2 from a reservoir to the surface is governed by the state of CO2 (supercritical vs. gaseous) and the pressure in the reservoir and the direct overburden. Reservoirs with gaseous CO2 is more prone to leak CO2 than reservoirs with dense supercritical CO2. If the reservoir pressure is close to or higher than the least principal stress leakage is likely to occur while reservoirs with pressures close to hydrostatic pressure and below 1200 m depth do not leak. Additionally, a positive pressure gradient from the reservoir into the caprock averts leakage of CO2 into the caprock. Leakage of CO2 occurs in all cases along a fault zone, indicating that

  2. CO2 Emission Factors for Coals

    Directory of Open Access Journals (Sweden)

    P. Orlović-Leko

    2015-03-01

    Full Text Available Emission factors are used in greenhouse gas inventories to estimate emissions from coal combustion. In the absence of direct measures, emissions factors are frequently used as a quick, low cost way to estimate emissions values. Coal combustion has been a major contributor to the CO2 flux into the atmosphere. Nearly all of the fuel carbon (99 % in coal is converted to CO2 during the combustion process. The carbon content is the most important coal parameter which is the measure of the degree of coalification (coal rank. Coalification is the alteration of vegetation to form peat, succeeded by the transformation of peat through lignite, sub-bituminous, bituminous to anthracite coal. During the geochemical or metamorphic stage, the progressive changes that occur within the coal are an increase in the carbon content and a decrease in the hydrogen and oxygen content resulting in a loss of volatiles. Heterogeneous composition of coal causes variation in CO2 emission from different coals. The IPCC (Intergovernmental Panel on Climate Change has produced guidelines on how to produce emission inventories which includes emission factors. Although 2006 IPCC Guidelines provided the default values specified according to the rank of the coal, the application of country-specific emission factors was recommended when estimating the national greenhouse gas emissions. This paper discusses the differences between country-specific emission factors and default IPCC CO2 emission factors, EF(CO2, for coals. Also, this study estimated EF(CO2 for two different types of coals and peat from B&H, on the basis fuel analyses. Carbon emission factors for coal mainly depend on the carbon content of the fuel and vary with both rank and geographic origin, which supports the idea of provincial variation of carbon emission factors. Also, various other factors, such as content of sulphur, minerals and macerals play an important role and influence EF(CO2 from coal. Carbonate minerals

  3. CO2-DSA in lower extremity veins: a clinical application

    International Nuclear Information System (INIS)

    Guo Jinhe; Teng Gaojun; Zhu Guangyu; Liu Zhensheng; Li Guozhao; Ding Huijuan; Shen Zhiping; He Shicheng; Deng Gang; Fang Wen

    2005-01-01

    Objective: To explore the feasibility and usefulness of carbon dioxide digital subtraction angiography (CO 2 -DSA) in deep veins of lower extremity via the dorsal is pedis vein. Methods: CO 2 -DSA in lower extremity veins was performed in 15 patients (15 limbs affected, male 9, female 6) by injection of CO 2 via the dorsal is pedis vein. Among them, 8 patients were suspected with deep venous thrombosis (DVT), 6 patients with saphena magna dilation, and 1 patient with a follow-up after thrombolysis due to DVT. Results: Excellent image was obtained in 12 cases, which showed branches of the venous system clearly, as well as the details of DVT. Good image was obtained in 2 cases. Technical failure was encountered in one patient due to inaccessible puncture veins. Mild discomfort (transient pain at the percutaneous site) during the procedure was demonstrated in 11 patients. There was no severe side effects or complications in this series. Conclusion: CO 2 -DSA in lower extremity veins is feasible and safe, the preliminary result is satisfactory. (authors)

  4. CaO-based CO2 sorbents: from fundamentals to the development of new, highly effective materials.

    Science.gov (United States)

    Kierzkowska, Agnieszka M; Pacciani, Roberta; Müller, Christoph R

    2013-07-01

    The enormous anthropogenic emission of the greenhouse gas CO2 is most likely the main reason for climate change. Considering the continuing and indeed growing utilisation of fossil fuels for electricity generation and transportation purposes, development and implementation of processes that avoid the associated emissions of CO2 are urgently needed. CO2 capture and storage, commonly termed CCS, would be a possible mid-term solution to reduce the emissions of CO2 into the atmosphere. However, the costs associated with the currently available CO2 capture technology, that is, amine scrubbing, are prohibitively high, thus making the development of new CO2 sorbents a highly important research challenge. Indeed, CaO, readily obtained through the calcination of naturally occurring limestone, has been proposed as an alternative CO2 sorbent that could substantially reduce the costs of CO2 capture. However, one of the major drawbacks of using CaO derived from natural sources is its rapidly decreasing CO2 uptake capacity with repeated carbonation-calcination reactions. Here, we review the current understanding of fundamental aspects of the cyclic carbonation-calcination reactions of CaO such as its reversibility and kinetics. Subsequently, recent attempts to develop synthetic, CaO-based sorbents that possess high and cyclically stable CO2 uptakes are presented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Elevated CO2 Increases Nitrogen Fixation at the Reproductive Phase Contributing to Various Yield Responses of Soybean Cultivars

    Directory of Open Access Journals (Sweden)

    Yansheng Li

    2017-09-01

    Full Text Available Nitrogen deficiency limits crop performance under elevated CO2 (eCO2, depending on the ability of plant N uptake. However, the dynamics and redistribution of N2 fixation, and fertilizer and soil N use in legumes under eCO2 have been little studied. Such an investigation is essential to improve the adaptability of legumes to climate change. We took advantage of genotype-specific responses of soybean to increased CO2 to test which N-uptake phenotypes are most strongly related to enhanced yield. Eight soybean cultivars were grown in open-top chambers with either 390 ppm (aCO2 or 550 ppm CO2 (eCO2. The plants were supplied with 100 mg N kg−1 soil as 15N-labeled calcium nitrate, and harvested at the initial seed-filling (R5 and full-mature (R8 stages. Increased yield in response to eCO2 correlated highly (r = 0.95 with an increase in symbiotically fixed N during the R5 to R8 stage. In contrast, eCO2 only led to small increases in the uptake of fertilizer-derived and soil-derived N during R5 to R8, and these increases did not correlate with enhanced yield. Elevated CO2 also decreased the proportion of seed N redistributed from shoot to seeds, and this decrease strongly correlated with increased yield. Moreover, the total N uptake was associated with increases in fixed-N per nodule in response to eCO2, but not with changes in nodule biomass, nodule density, or root length.

  6. Plant growth responses to elevated atmospheric CO2 are increased by phosphorus sufficiency but not by arbuscular mycorrhizas.

    Science.gov (United States)

    Jakobsen, Iver; Smith, Sally E; Smith, F Andrew; Watts-Williams, Stephanie J; Clausen, Signe S; Grønlund, Mette

    2016-11-01

    Capturing the full growth potential in crops under future elevated CO 2 (eCO 2 ) concentrations would be facilitated by improved understanding of eCO 2 effects on uptake and use of mineral nutrients. This study investigates interactions of eCO 2 , soil phosphorus (P), and arbuscular mycorrhizal (AM) symbiosis in Medicago truncatula and Brachypodium distachyon grown under the same conditions. The focus was on eCO 2 effects on vegetative growth, efficiency in acquisition and use of P, and expression of phosphate transporter (PT) genes. Growth responses to eCO 2 were positive at P sufficiency, but under low-P conditions they ranged from non-significant in M. truncatula to highly significant in B. distachyon Growth of M. truncatula was increased by AM at low P conditions at both CO 2 levels and eCO 2 ×AM interactions were sparse. Elevated CO 2 had small effects on P acquisition, but enhanced conversion of tissue P into biomass. Expression of PT genes was influenced by eCO 2 , but effects were inconsistent across genes and species. The ability of eCO 2 to partly mitigate P limitation-induced growth reductions in B. distachyon was associated with enhanced P use efficiency, and requirements for P fertilizers may not increase in such species in future CO 2 -rich climates. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  7. CO2-induced seawater acidification affects physiological performance of the marine diatom Phaeodactylum tricornutum

    Directory of Open Access Journals (Sweden)

    U. Riebesell

    2010-09-01

    Full Text Available CO2/pH perturbation experiments were carried out under two different pCO2 levels (39.3 and 101.3 Pa to evaluate effects of CO2-induced ocean acidification on the marine diatom Phaeodactylum tricornutum. After acclimation (>20 generations to ambient and elevated CO2 conditions (with corresponding pH values of 8.15 and 7.80, respectively, growth and photosynthetic carbon fixation rates of high CO2 grown cells were enhanced by 5% and 12%, respectively, and dark respiration stimulated by 34% compared to cells grown at ambient CO2. The half saturation constant (Km for carbon fixation (dissolved inorganic carbon, DIC increased by 20% under the low pH and high CO2 condition, reflecting a decreased affinity for HCO3– or/and CO2 and down-regulated carbon concentrating mechanism (CCM. In the high CO2 grown cells, the electron transport rate from photosystem II (PSII was photoinhibited to a greater extent at high levels of photosynthetically active radiation, while non-photochemical quenching was reduced compared to low CO2 grown cells. This was probably due to the down-regulation of CCM, which serves as a sink for excessive energy. The balance between these positive and negative effects on diatom productivity will be a key factor in determining the net effect of rising atmospheric CO2 on ocean primary production.

  8. Utopia Switzerland (2) - A Country Without CO2 Emissions

    International Nuclear Information System (INIS)

    Streit, Marco

    2008-01-01

    Global warming and climate change are major themes in the today's energy policy discussion. Awarding Al Gore and the IPCC with the Nobel price in