WorldWideScience

Sample records for subambient co2 concentrations

  1. The effect of subambient to elevated atmospheric CO2 concentration on vascular function in Helianthus annuus: Implications for plant response to climate change

    Science.gov (United States)

    Plant gas-exchange is regulated by stomata, which co-ordinate leaf-level water loss with xylem transport. Stomatal opening responds to internal levels of CO2 in the leaf but changing CO2 can also lead to changes in stomatal density that influence transpiration. Given that stomatal conductance increa...

  2. 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...

  3. ISLSCP II Globalview: Atmospheric CO2 Concentrations

    Data.gov (United States)

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

  4. Multi-Year Leaf-Level Response to Sub-Ambient and Elevated Experimental CO2 in Betula nana

    NARCIS (Netherlands)

    Hincke, Alexandra J C; Broere, Tom; Kürschner, Wolfram M; Donders, Timme H; Wagner-Cremer, Friederike

    2016-01-01

    The strong link between stomatal frequency and CO2 in woody plants is key for understanding past CO2 dynamics, predicting future change, and evaluating the significant role of vegetation in the hydrological cycle. Experimental validation is required to evaluate the long-term adaptive leaf response

  5. Multi-Year Leaf-Level Response to Sub-Ambient and Elevated Experimental CO2 in Betula nana.

    Directory of Open Access Journals (Sweden)

    Alexandra J C Hincke

    Full Text Available The strong link between stomatal frequency and CO2 in woody plants is key for understanding past CO2 dynamics, predicting future change, and evaluating the significant role of vegetation in the hydrological cycle. Experimental validation is required to evaluate the long-term adaptive leaf response of C3 plants to CO2 conditions; however, studies to date have only focused on short-term single-season experiments and may not capture (1 the full ontogeny of leaves to experimental CO2 exposure or (2 the true adjustment of structural stomatal properties to CO2, which we postulate is likely to occur over several growing seasons. We conducted controlled growth chamber experiments at 150 ppmv, 450 ppmv and 800 ppmv CO2 with woody C3 shrub Betula nana (dwarf birch over two successive annual growing seasons and evaluated the structural stomatal response to atmospheric CO2 conditions. We find that while some adjustment of leaf morphological and stomatal parameters occurred in the first growing season where plants are exposed to experimental CO2 conditions, amplified adjustment of non-plastic stomatal properties such as stomatal conductance occurred in the second year of experimental CO2 exposure. We postulate that the species response limit to CO2 of B. nana may occur around 400-450 ppmv. Our findings strongly support the necessity for multi-annual experiments in C3 perennials in order to evaluate the effects of environmental conditions and provide a likely explanation of the contradictory results between historical and palaeobotanical records and experimental data.

  6. Passive CO2 concentration in higher plants.

    Science.gov (United States)

    Sage, Rowan F; Khoshravesh, Roxana

    2016-06-01

    Photorespiratory limitations on C3 photosynthesis are substantial in warm, low CO2 conditions. To compensate, certain plants evolved mechanisms to actively concentrate CO2 around Rubisco using ATP-supported CO2 pumps such as C4 photosynthesis. Plants can also passively accumulate CO2 without additional ATP expenditure by localizing the release of photorespired and respired CO2 around Rubisco that is diffusively isolated from peripheral air spaces. Passive accumulation of photorespired CO2 occurs when glycine decarboxylase is localized to vascular sheath cells in what is termed C2 photosynthesis, and through forming sheaths of chloroplasts around the periphery of mesophyll cells. The peripheral sheaths require photorespired CO2 to re-enter chloroplasts where it can be refixed. Passive accumulation of respiratory CO2 is common in organs such as stems, fruits and flowers, due to abundant heterotrophic tissues and high diffusive resistance along the organ periphery. Chloroplasts within these organs are able to exploit this high CO2 to reduce photorespiration. CO2 concentration can also be enhanced passively by channeling respired CO2 from roots and rhizomes into photosynthetic cells of stems and leaves via lacunae, aerenchyma and the xylem stream. Through passive CO2 concentration, C3 species likely improved their carbon economy and maintained fitness during episodes of low atmospheric CO2. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Zinc depolarized electrochemical CO2 concentration

    Science.gov (United States)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.

    1975-01-01

    Two zinc depolarized electrochemical carbon dioxide concentrator concepts were analytically and experimentally evaluated for portable life support system carbon dioxide (CO2) removal application. The first concept, referred to as the zinc hydrogen generator electrochemical depolarized CO2 concentrator, uses a ZHG to generate hydrogen for direct use in an EDC. The second concept, referred to as the zinc/electrochemical depolarized concentrator, uses a standard EDC cell construction modified for use with the Zn anode. The Zn anode is consumed and subsequently regenerated, thereby eliminating the need to supply H2 to the EDC for the CO2 removal process. The evaluation was based primarily on an analytical evaluation of the two ZnDCs at projected end item performance and hardware design levels. Both ZnDC concepts for PLSS CO2 removal application were found to be noncompetitive in both total equivalent launch weight and individual extravehicular activity mission volume when compared to other candidate regenerable PLSS CO2 scrubbers.

  8. The Effects of Inorganic Nitrogen form and CO2 Concentration on Wheat Yield and Nutrient Accumulation and Distribution

    Science.gov (United States)

    Carlisle, Eli; Myers, Samuel; Raboy, Victor; Bloom, Arnold

    2012-01-01

    Inorganic N is available to plants from the soil as ammonium (NH4+) and nitrate (NO3-). We studied how wheat grown hydroponically to senescence in controlled environmental chambers is affected by N form (NH4+ vs. NO3−) and CO2 concentration (“subambient,” “ambient,” and “elevated”) in terms of biomass, yield, and nutrient accumulation and partitioning. Wheat supplied with NH4+ as a sole N source had the strongest response to CO2 concentration. Plants exposed to subambient and ambient CO2 concentrations typically had the greatest biomass and nutrient accumulation under both N forms. In general NH4+-supplied plants had higher concentrations of total N, P, K, S, Ca, Zn, Fe, and Cu, while NO3--supplied plants had higher concentrations of Mg, B, Mn, and NO3- - N. NH4+-supplied plants contained amounts of phytate similar to NO3−-supplied plants but had higher bioavailable Zn, which could have consequences for human health. NH4+-supplied plants allocated more nutrients and biomass to aboveground tissues whereas NO3+-supplied plants allocated more nutrients to the roots. The two inorganic nitrogen forms influenced plant growth and nutrient status so distinctly that they should be treated as separate nutrients. Moreover, plant growth and nutrient status varied in a non-linear manner with atmospheric CO2 concentration. PMID:22969784

  9. Yield responses of wild C3and C4crop progenitors to subambient CO2: a test for the role of CO2limitation in the origin of agriculture.

    Science.gov (United States)

    Cunniff, Jennifer; Jones, Glynis; Charles, Michael; Osborne, Colin P

    2017-01-01

    Limitation of plant productivity by the low partial pressure of atmospheric CO 2 (C a ) experienced during the last glacial period is hypothesized to have been an important constraint on the origins of agriculture. In support of this hypothesis, previous work has shown that glacial C a limits vegetative growth in the wild progenitors of both C 3 and C 4 founder crops. Here, we present data showing that glacial C a also reduces grain yield in both crop types. We grew four wild progenitors of C 3 (einkorn wheat and barley) and C 4 crops (foxtail and broomcorn millets) at glacial and postglacial C a , measuring grain yield and the morphological and physiological components contributing to these yield changes. The C 3 species showed a significant increase in unthreshed grain yield of ~50% with the glacial to postglacial increase in C a , which matched the stimulation of photosynthesis, suggesting that increases in photosynthesis are directly translated into yield at subambient levels of C a . Increased yield was controlled by a higher rate of tillering, leading to a larger number of tillers bearing fertile spikes, and increases in seed number and size. The C 4 species showed smaller, but significant, increases in grain yield of 10-15%, arising from larger seed numbers and sizes. Photosynthesis was enhanced by C a in only one C 4 species and the effect diminished during development, suggesting that an indirect mechanism mediated by plant water relations could also be playing a role in the yield increase. Interestingly, the C 4 species at glacial C a showed some evidence that photosynthetic capacity was upregulated to enhance carbon capture. Development under glacial C a also impacted negatively on the subsequent germination and viability of seeds. These results suggest that the grain production of both C 3 and C 4 crop progenitors was limited by the atmospheric conditions of the last glacial period, with important implications for the origins of agriculture. © 2016

  10. Contribution of various carbon sources toward isoprene biosynthesis in poplar leaves mediated by altered atmospheric CO2 concentrations.

    Directory of Open Access Journals (Sweden)

    Amy M Trowbridge

    Full Text Available Biogenically released isoprene plays important roles in both tropospheric photochemistry and plant metabolism. We performed a (13CO(2-labeling study using proton-transfer-reaction mass spectrometry (PTR-MS to examine the kinetics of recently assimilated photosynthate into isoprene emitted from poplar (Populus × canescens trees grown and measured at different atmospheric CO(2 concentrations. This is the first study to explicitly consider the effects of altered atmospheric CO(2 concentration on carbon partitioning to isoprene biosynthesis. We studied changes in the proportion of labeled carbon as a function of time in two mass fragments, M41(+, which represents, in part, substrate derived from pyruvate, and M69(+, which represents the whole unlabeled isoprene molecule. We observed a trend of slower (13C incorporation into isoprene carbon derived from pyruvate, consistent with the previously hypothesized origin of chloroplastic pyruvate from cytosolic phosphenolpyruvate (PEP. Trees grown under sub-ambient CO(2 (190 ppmv had rates of isoprene emission and rates of labeling of M41(+ and M69(+ that were nearly twice those observed in trees grown under elevated CO(2 (590 ppmv. However, they also demonstrated the lowest proportion of completely labeled isoprene molecules. These results suggest that under reduced atmospheric CO(2 availability, more carbon from stored/older carbon sources is involved in isoprene biosynthesis, and this carbon most likely enters the isoprene biosynthesis pathway through the pyruvate substrate. We offer direct evidence that extra-chloroplastic rather than chloroplastic carbon sources are mobilized to increase the availability of pyruvate required to up-regulate the isoprene biosynthesis pathway when trees are grown under sub-ambient CO(2.

  11. A usage of CO2 hydrate: convenient method to increase CO2 concentration in culturing algae.

    Science.gov (United States)

    Nakano, Sho; Chang, Kwang-Hyeon; Shijima, Atsushi; Miyamoto, Hiroyuki; Sato, Yukio; Noto, Yuji; Ha, Jin-Yong; Sakamoto, Masaki

    2014-11-01

    The addition of CO2 to algal culture systems can increase algal biomass effectively. Generally, gas bubbling is used to increase CO2 levels in culture systems; however, it is difficult to quantitatively operate to control the concentration using this method. In this study, we tested the usability of CO2 hydrate for phytoplankton culture. Specifically, green algae Pseudokirchneriella subcapitata were cultured in COMBO medium that contained dissolved CO2 hydrate, after which its effects were evaluated. The experiment was conducted according to a general bioassay procedure (OECD TG201). CO2 promoted algae growth effectively (about 2-fold relative to the control), and the decrease in pH due to dissolution of the CO2 in water recovered soon because of photosynthesis. Since the CO2 hydrate method can control a CO2 concentration easily and quantitatively, it is expected to be useful in future applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Dynamics of CO2 fluxes and concentrations during a shallow subsurface CO2 release

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, J.L.; Hilley, G.E.; Dobeck, L.; Spangler, L.

    2009-09-01

    A field facility located in Bozeman, Montana provides the opportunity to test methods to detect, locate, and quantify potential CO2 leakage from geologic storage sites. From 9 July to 7 August 2008, 0.3 t CO2 d{sup -1} were injected from a 100-m long, {approx}2.5 m deep horizontal well. Repeated measurements of soil CO2 fluxes on a grid characterized the spatio-temporal evolution of the surface leakage signal and quantified the surface leakage rate. Infrared CO2 concentration sensors installed in the soil at 30 cm depth at 0 to 10 m from the well and at 4 cm above the ground at 0 and 5 m from the well recorded surface breakthrough of CO2 leakage and migration of CO2 leakage through the soil. Temporal variations in CO2 concentrations were correlated with atmospheric and soil temperature, wind speed, atmospheric pressure, rainfall, and CO2 injection rate.

  13. Photocatalytic Reduction of Low Concentration of CO2.

    Science.gov (United States)

    Nakajima, Takuya; Tamaki, Yusuke; Ueno, Kazuki; Kato, Eishiro; Nishikawa, Tetsuya; Ohkubo, Kei; Yamazaki, Yasuomi; Morimoto, Tatsuki; Ishitani, Osamu

    2016-10-05

    A novel molecular photocatalytic system with not only high reduction ability of CO2 but also high capture ability of CO2 has been developed using a Ru(II)-Re(I) dinuclear complex as a photocatalyst. By using this photocatalytic system, CO2 of 10% concentration could be selectively converted to CO with almost same photocatalysis to that under a pure CO2 atmosphere (TONCO > 1000, ΦCO > 0.4). Even 0.5% concentration of CO2 was reduced with 60% initial efficiency of CO formation by using the same system compared to that using pure CO2 (TONCO > 200). The Re(I) catalyst unit in the photocatalyst can efficiently capture CO2, which proceeds CO2 insertion to the Re-O bond, and then reduce the captured CO2 by using an electron supplied from the photochemically reduced Ru photosensitizer unit.

  14. Investigation into Optimal CO2 Concentration for CO2 Capture from Aluminium Production

    OpenAIRE

    Mathisen, Anette; Sørensen, Henriette; Melaaen, Morten; Müller, Gunn-Iren

    2013-01-01

    Capture of CO2 from aluminum production has been simulated using Aspen Plus and Aspen Hysys. The technology used for aluminum production is the Hall-Héroult and the current cell design necessitates that large amounts of false air is supplied to the cells. This results in a CO2 concentration in the process gas at around 1 vol%, which is considered uneconomical for CO2 capture. Therefore, the aim of this investigation is to evaluate the CO2 capture from aluminum production when the process gas ...

  15. A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function.

    Science.gov (United States)

    Fay, Philip A; Reichmann, Lara G; Aspinwall, Michael J; Khasanova, Albina R; Polley, H Wayne

    2015-11-21

    Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most experiments examine only two or a few levels of CA concentration and a single soil type, but if CA can be varied as a gradient from subambient to superambient concentrations on multiple soils, we can discern whether past ecosystem responses may continue linearly in the future and whether responses may vary across the landscape. The Lysimeter Carbon Dioxide Gradient Facility applies a 250 to 500 µl L(-1) CA gradient to Blackland prairie plant communities established on lysimeters containing clay, silty clay, and sandy soils. The gradient is created as photosynthesis by vegetation enclosed in in temperature-controlled chambers progressively depletes carbon dioxide from air flowing directionally through the chambers. Maintaining proper air flow rate, adequate photosynthetic capacity, and temperature control are critical to overcome the main limitations of the system, which are declining photosynthetic rates and increased water stress during summer. The facility is an economical alternative to other techniques of CA enrichment, successfully discerns the shape of ecosystem responses to subambient to superambient CA enrichment, and can be adapted to test for interactions of carbon dioxide with other greenhouse gases such as methane or ozone.

  16. Effects of CO2 on stomatal conductance: do stomata open at very high CO2 concentrations?

    Science.gov (United States)

    Wheeler, R. M.; Mackowiak, C. L.; Yorio, N. C.; Sager, J. C.

    1999-01-01

    Potato and wheat plants were grown for 50 d at 400, 1000 and 10000 micromoles mol-1 carbon dioxide (CO2). and sweetpotato and soybean were grown at 1000 micromoles mol-1 CO2 in controlled environment chambers to study stomatal conductance and plant water use. Lighting was provided with fluorescent lamps as a 12 h photoperiod with 300 micromoles m-2 s-1 PAR. Mid-day stomatal conductances for potato were greatest at 400 and 10000 micromoles mol-1 and least at 1000 micromoles mol-1 CO2. Mid-day conductances for wheat were greatest at 400 micromoles mol-1 and least at 1000 and 10000 micromoles mol-1 CO2. Mid-dark period conductances for potato were significantly greater at 10000 micromoles mol-1 than at 400 or 1000 micromoles mol-1, whereas dark conductance for wheat was similar in all CO2 treatments. Temporarily changing the CO2 concentration from the native 1000 micromoles mol-1 to 400 micromoles mol-1 increased mid-day conductance for all species, while temporarily changing from 1000 to 10000 micromoles mol-1 also increased conductance for potato and sweetpotato. Temporarily changing the dark period CO2 from 1000 to 10000 micromoles mol-1 increased conductance for potato, soybean and sweetpotato. In all cases, the stomatal responses were reversible, i.e. conductances returned to original rates following temporary changes in CO2 concentration. Canopy water use for potato was greatest at 10000, intermediate at 400, and least at 1000 micromoles mol-1 CO2, whereas canopy water use for wheat was greatest at 400 and similar at 1000 and 10000 micromoles mol-1 CO2. Elevated CO2 treatments (i.e. 1000 and 10000 micromoles mol-1) resulted in increased plant biomass for both wheat and potato relative to 400 micromoles mol-1, and no injurious effects were apparent from the 10000 micromoles mol-1 treatment. Results indicate that super-elevated CO2 (i.e. 10000 micromoles mol-1) can increase stomatal conductance in some species, particularly during the dark period, resulting in

  17. Integration of the electrochemical depolorized CO2 concentrator with the Bosch CO2 reduction subsystem

    Science.gov (United States)

    Schubert, F. H.; Wynveen, R. A.; Hallick, T. M.

    1976-01-01

    Regenerative processes for the revitalization of spacecraft atmospheres require an Oxygen Reclamation System (ORS) for the collection of carbon dioxide and water vapor and the recovery of oxygen from these metabolic products. Three life support subsystems uniquely qualified to form such an ORS are an Electrochemical CO2 Depolarized Concentrator (EDC), a CO2 Reduction Subsystem (BRS) and a Water Electrolysis Subsystem (WES). A program to develop and test the interface hardware and control concepts necessary for integrated operation of a four man capacity EDC with a four man capacity BRS was successfully completed. The control concept implemented proved successful in operating the EDC with the BRS for both constant CO2 loading as well as variable CO2 loading, based on a repetitive mission profile of the Space Station Prototype (SSP).

  18. Electrochemical CO2 concentration for the Space Station Program

    Science.gov (United States)

    Lance, N.; Schwartz, M.; Boyda, R. B.

    1985-01-01

    Under the sponsorship of NASA, Electrochemical Carbon Dioxide (CO2) Concentration EDC technology has been developed that removes CO2 continuously or cyclically from low CO2 partial pressure (400 Pa) atmospheres with the performance and operating characteristics required for Space Station applications. The most recent advancement of this technology is the development of an advanced preprototype subsystem, the CS-3A, to remove the metabolic CO2 produced by three persons from the projected Space Station atmosphere. This paper provides an overview of EDC technology, shows how it is ideally suited for Space Station application, and presents technology enhancements that will be demonstrated by the CS-3A subsystem development program.

  19. [CO2-Concentrating Mechanism and Its Traits in Haloalkaliphilic Cyanobacteria].

    Science.gov (United States)

    Kupriyanova, E V; Samylina, O S

    2015-01-01

    Cyanobacteria are a group of oxygenic phototrophs existing for at least 3.5 Ga. Photosynthetic CO2 assimilation by cyanobacteria occurs via the Calvin cycle, with RuBisCO, its key enzyme, having very low affinity to CO2. This is due to the fact that atmospheric CO2 concentration in Archaean, when the photosynthetic apparatus evolved, was several orders higher than now. Later, in the epoch of Precambrian microbial communities, CO2 content in the atmosphere decreased drastically. Thus, present-day phototrophs, including cyanobacteria, require adaptive mechanisms for efficient photosynthesis. In cyanobacterial cells, this function is performed by the CO2-concentrating mechanism (CCM), which creates elevated CO2 concentrations in the vicinity of RuBisCO active centers, thus significantly increasing the rate of CO2 fixation in the Calvin cycle. CCM has been previously studied only for freshwater and marine cyanobacteria. We were the first to investigate CCM in haloalkaliphilic cyanobacteria from soda lakes. Extremophilic haloalkaliphilic cyanobacteria were shown to possess a well-developed CCM with the structure and functional principles similar to those of freshwater and marine strains. Analysis of available data suggests that regulation of the amount of inorganic carbon transported into the cell is probably the general CCM function under these conditions.

  20. Mapping Global Atmospheric CO2 Concentration at High Spatiotemporal Resolution

    Directory of Open Access Journals (Sweden)

    Yingying Jing

    2014-11-01

    Full Text Available Satellite measurements of the spatiotemporal distributions of atmospheric CO2 concentrations are a key component for better understanding global carbon cycle characteristics. Currently, several satellite instruments such as the Greenhouse gases Observing SATellite (GOSAT, SCanning Imaging Absorption Spectrometer for Atmospheric CHartographY (SCIAMACHY, and Orbiting Carbon Observatory-2 can be used to measure CO2 column-averaged dry air mole fractions. However, because of cloud effects, a single satellite can only provide limited CO2 data, resulting in significant uncertainty in the characterization of the spatiotemporal distribution of atmospheric CO2 concentrations. In this study, a new physical data fusion technique is proposed to combine the GOSAT and SCIAMACHY measurements. On the basis of the fused dataset, a gap-filling method developed by modeling the spatial correlation structures of CO2 concentrations is presented with the goal of generating global land CO2 distribution maps with high spatiotemporal resolution. The results show that, compared with the single satellite dataset (i.e., GOSAT or SCIAMACHY, the global spatial coverage of the fused dataset is significantly increased (reaching up to approximately 20%, and the temporal resolution is improved by two or three times. The spatial coverage and monthly variations of the generated global CO2 distributions are also investigated. Comparisons with ground-based Total Carbon Column Observing Network (TCCON measurements reveal that CO2 distributions based on the gap-filling method show good agreement with TCCON records despite some biases. These results demonstrate that the fused dataset as well as the gap-filling method are rather effective to generate global CO2 distribution with high accuracies and high spatiotemporal resolution.

  1. The possible evolution and future of CO2-concentrating mechanisms.

    Science.gov (United States)

    Raven, John A; Beardall, John; Sánchez-Baracaldo, Patricia

    2017-06-01

    CO2-concentrating mechanisms (CCMs), based either on active transport of inorganic carbon (biophysical CCMs) or on biochemistry involving supplementary carbon fixation into C4 acids (C4 and CAM), play a major role in global primary productivity. However, the ubiquitous CO2-fixing enzyme in autotrophs, Rubisco, evolved at a time when atmospheric CO2 levels were very much higher than today and O2 was very low and, as CO2 and O2 approached (by no means monotonically), today's levels, at some time subsequently many organisms evolved a CCM that increased the supply of CO2 and decreased Rubisco oxygenase activity. Given that CO2 levels and other environmental factors have altered considerably between when autotrophs evolved and the present day, and are predicted to continue to change into the future, we here examine the drivers for, and possible timing of, evolution of CCMs. CCMs probably evolved when CO2 fell to 2-16 times the present atmospheric level, depending on Rubisco kinetics. We also assess the effects of other key environmental factors such as temperature and nutrient levels on CCM activity and examine the evidence for evolutionary changes in CCM activity and related cellular processes as well as limitations on continuity of CCMs through environmental variations. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. [Effects of plastic film mulching on soil CO2 efflux and CO2 concentration in an oasis cotton field].

    Science.gov (United States)

    Yu, Yong-xiang; Zhao, Cheng-yi; Jia, Hong-tao; Yu, Bo; Zhou, Tian-he; Yang, Yu-guang; Zhao, Hua

    2015-01-01

    A field study was conducted to compare soil CO2 efflux and CO2 concentration between mulched and non-mulched cotton fields by using closed chamber method and diffusion chamber technique. Soil CO2 efflux and CO2 concentration exhibited a similar seasonal pattern, decreasing from July to October. Mulched field had a lower soil CO2 efflux but a higher CO2 concentration, compared to those of non-mulched fields. Over the measurement period, cumulative CO2 efflux was 1871.95 kg C . hm-2 for mulched field and 2032.81 kg C . hm-2 for non-mulched field. Soil CO2 concentration was higher in mulched field (ranging from 5137 to 25945 µL . L-1) than in non- mulched field (ranging from 2165 to 23986 µL . L-1). The correlation coefficients between soil CO2 concentrations at different depths and soil CO2 effluxes were 0.60 to 0.73 and 0.57 to 0.75 for the mulched and non-mulched fields, indicating that soil CO2 concentration played a crucial role in soil CO2 emission. The Q10 values were 2.77 and 2.48 for the mulched and non-mulched fields, respectively, suggesting that CO2 efflux in mulched field was more sensitive to the temperature.

  3. Estimates of CO2 traffic emissions from mobile concentration measurements

    Science.gov (United States)

    Maness, H. L.; Thurlow, M. E.; McDonald, B. C.; Harley, R. A.

    2015-03-01

    We present data from a new mobile system intended to aid in the design of upcoming urban CO2-monitoring networks. Our collected data include GPS probe data, video-derived traffic density, and accurate CO2 concentration measurements. The method described here is economical, scalable, and self-contained, allowing for potential future deployment in locations without existing traffic infrastructure or vehicle fleet information. Using a test data set collected on California Highway 24 over a 2 week period, we observe that on-road CO2 concentrations are elevated by a factor of 2 in congestion compared to free-flow conditions. This result is found to be consistent with a model including vehicle-induced turbulence and standard engine physics. In contrast to surface concentrations, surface emissions are found to be relatively insensitive to congestion. We next use our model for CO2 concentration together with our data to independently derive vehicle emission rate parameters. Parameters scaling the leading four emission rate terms are found to be within 25% of those expected for a typical passenger car fleet, enabling us to derive instantaneous emission rates directly from our data that compare generally favorably to predictive models presented in the literature. The present results highlight the importance of high spatial and temporal resolution traffic data for interpreting on- and near-road concentration measurements. Future work will focus on transport and the integration of mobile platforms into existing stationary network designs.

  4. Diversity of CO2-concentrating mechanisms and responses to CO2 concentration in marine and freshwater diatoms.

    Science.gov (United States)

    Clement, Romain; Jensen, Erik; Prioretti, Laura; Maberly, Stephen C; Gontero, Brigitte

    2017-06-01

    The presence of CO2-concentrating mechanisms (CCMs) is believed to be one of the characteristics that allows diatoms to thrive in many environments and to be major contributors to global productivity. Here, the type of CCM and the responses to variable CO2 concentration were studied in marine and freshwater diatoms. At 400 ppm, there was a large diversity in physiological and biochemical mechanisms among the species. While Phaeodactylum tricornutum mainly used HCO3-, Thalassiosira pseudonana mainly used CO2. Carbonic anhydrase was an important component of the CCM in all species and C4 metabolism was absent, even with T. weissflogii. For all species, at 20 000 ppm, the affinity for dissolved inorganic carbon was lower than at 400 ppm CO2 and the reliance on CO2 was higher. Despite the difference in availability of inorganic carbon in marine and fresh waters, there were only small differences in CCMs between species from the two environments, and Navicula pelliculosa behaved similarly when grown in the two environments. The results suggest that species-specific differences are great, and more important than environmental differences in determining the nature and effectiveness of the CCM in diatoms. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  5. Research of CO2 concentration in naturally ventilated lecture room

    Science.gov (United States)

    Laska, Marta; Dudkiewicz, Edyta

    2017-11-01

    Naturally ventilated buildings especially dedicated for educational purposes need to be design to achieve required level of thermal comfort and indoor air quality. It is crucial in terms of both: health and productivity of the room users. Higher requirements of indoor environment are important due to the level of students concentration, their ability to acquire new knowledge and willingness to interact with the lecturer. The article presents the results of experimental study and surveys undertaken in naturally ventilated lecture room. The data is analysed in terms of CO2 concentration and its possible influence on users. Furthermore the outcome of the research is compared with the CO2 concentration models available in the literature.

  6. Dynamics of soil CO 2 efflux under varying atmospheric CO 2 concentrations reveal dominance of slow processes

    Science.gov (United States)

    Dohyoung Kim; Ram Oren; James S. Clark; Sari Palmroth; A. Christopher Oishi; Heather R. McCarthy; Chris A. Maier; Kurt Johnsen

    2017-01-01

    We evaluated the effect on soil CO2 efflux (FCO2) of sudden changes in photosynthetic rates by altering CO2 concentration in plots subjected to +200 ppmv for 15 years. Five-day intervals of exposure to elevated CO2 (eCO2) ranging 1.0–1.8 times ambient did not affect FCO2. FCO2 did not decrease until 4 months after termination of the long-term eCO2 treatment, longer...

  7. 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)

  8. Application of Commercial Non-Dispersive Infrared Spectroscopy Sensors for Sub-Ambient Carbon Dioxide Detection

    Science.gov (United States)

    Swickrath, Michael J.; Anderson, Molly; McMillin, Summer; Broerman, Craig

    2012-01-01

    Monitoring carbon dioxide (CO2) concentration within a spacecraft or spacesuit is critically important to ensuring the safety of the crew. Carbon dioxide uniquely absorbs light at wavelengths of 3.95 micrometers and 4.26 micrometers. As a result, non-dispersive infrared (NDIR) spectroscopy can be employed as a reliable and inexpensive method for the quantification of CO2 within the atmosphere. A multitude of commercial off-the-shelf (COTS) NDIR sensors exist for CO2 quantification. The COTS sensors provide reasonable accuracy as long as the measurements are attained under conditions close to the calibration conditions of the sensor (typically 21.1 C (70.0 F) and 1 atmosphere). However, as pressure deviates from atmospheric to the pressures associated with a spacecraft (8.0{10.2 pounds per square inch absolute (psia)) or spacesuit (4.1{8.0 psia), the error in the measurement grows increasingly large. In addition to pressure and temperature dependencies, the infrared transmissivity through a volume of gas also depends on the composition of the gas. As the composition is not known a priori, accurate sub-ambient detection must rely on iterative sensor compensation techniques. This manuscript describes the development of recursive compensation algorithms for sub-ambient detection of CO2 with COTS NDIR sensors. In addition, the source of the exponential loss in accuracy is developed theoretically. The basis of the loss can be explained through thermal, Doppler, and Lorentz broadening effects that arise as a result of the temperature, pressure, and composition of the gas mixture under analysis. This manuscript provides an approach to employing COTS sensors at sub-ambient conditions and may also lend insight into designing future NDIR sensors for aerospace application.

  9. BOREAS TE-5 CO2 Concentration and Stable Isotope Composition

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Ehleriinger, Jim; Brooks, J. Renee; Flanagan, Larry

    2000-01-01

    The BOREAS TE-5 team collected measurements in the NSA and SSA on gas exchange, gas composition, and tree growth. This data set contains measurements of the concentration and stable carbon (C-13/C-12 and oxygen (O-18/O-16) isotope ratios of atmospheric CO2 in air samples collected at different heights within forest canopies. The data were collected to determine the influence of photosynthesis and respiration by the forest ecosystems on the concentration and stable isotope ratio of atmospheric CO2 These measurements were collected at the SSA during each 1994 IFC at OJP, OBS, and OA sites. Measurements were also collected at the NSA during each 1994 IFC at the OJP, T6R5S TE UBS, and T2Q6A TE OA sites. The stable isotope ratios are expressed using standard delta notation and in units of per mil. The isotope ratios are expressed relative to the international standard, PDB, for both carbon and oxygen samples. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Activity Archive Center (DAAC).

  10. Designing an oscillating CO2 concentration experiment for field chambers

    Science.gov (United States)

    Questions have arisen about photosynthetic response to fluctuating carbon dioxide (CO2), which might affect yield in free-air CO2 enrichment (FACE) systems and in open top chambers. A few studies have been conducted based on CO2 controlled to cycles of fixed time-periods and fixed, large amplitude....

  11. Designing an oscillating CO2 concentration experiment for fild chambers

    Science.gov (United States)

    Questions have arisen about photosynthetic response to fluctuating carbon dioxide (CO2), which might affect yield in free-air CO2 enrichment (FACE) systems and in open top chambers. A few studies have been conducted based on CO2 controlled to cycles of fixed time-periods and fixed, large amplitude....

  12. A Global Perspective of Atmospheric CO2 Concentrations

    Science.gov (United States)

    Putman, William M.; Ott, Lesley; Darmenov, Anton; daSilva, Arlindo

    2016-01-01

    Carbon dioxide (CO2) is the most important greenhouse gas affected by human activity. About half of the CO2 emitted from fossil fuel combustion remains in the atmosphere, contributing to rising temperatures, while the other half is absorbed by natural land and ocean carbon reservoirs. Despite the importance of CO2, many questions remain regarding the processes that control these fluxes and how they may change in response to a changing climate. The Orbiting Carbon Observatory-2 (OCO-2), launched on July 2, 2014, is NASA's first satellite mission designed to provide the global view of atmospheric CO2 needed to better understand both human emissions and natural fluxes. This visualization shows how column CO2 mixing ratio, the quantity observed by OCO-2, varies throughout the year. By observing spatial and temporal gradients in CO2 like those shown, OCO-2 data will improve our understanding of carbon flux estimates. But, CO2 observations can't do that alone. This visualization also shows that column CO2 mixing ratios are strongly affected by large-scale weather systems. In order to fully understand carbon flux processes, OCO-2 observations and atmospheric models will work closely together to determine when and where observed CO2 came from. Together, the combination of high-resolution data and models will guide climate models towards more reliable predictions of future conditions.

  13. Soil CO2 concentration does not affect growth or root respiration in bean or citrus

    NARCIS (Netherlands)

    Bouma, T.J.; Nielsen, K.F.; Eissenstat, D.M.; Lynch, J.P.

    1997-01-01

    Contrasting effects of soil CO2 concentration on root respiration rates during short-term CO2 exposure, and on plant growth during long-term CO2 exposure, have been reported, Here we examine the effects of both short-and long-term exposure to soil CO2 on the root respiration of intact plants and on

  14. Autotrophic and heterotrophic soil respiration determined with trenching, soil CO2 fluxes and 13CO2/12CO2 concentration gradients in a boreal forest ecosystem

    Science.gov (United States)

    Pumpanen, Jukka; Shurpali, Narasinha; Kulmala, Liisa; Kolari, Pasi; Heinonsalo, Jussi

    2017-04-01

    Soil CO2 efflux forms a substantial part of the ecosystem carbon balance, and it can contribute more than half of the annual ecosystem respiration. Recently assimilated carbon which has been fixed in photosynthesis during the previous days plays an important role in soil CO2 efflux, and its contribution is seasonally variable. Moreover, the recently assimilated C has been shown to stimulate the decomposition of recalcitrant C in soil and increase the mineralization of nitrogen, the most important macronutrient limiting gross primary productivity (GPP) in boreal ecosystems. Podzolic soils, typical in boreal zone, have distinctive layers with different biological and chemical properties. The biological activity in different soil layers has large seasonal variation due to vertical gradient in temperature, soil organic matter and root biomass. Thus, the source of CO2 and its components have a vertical gradient which is seasonally variable. The contribution of recently assimilated C and its seasonal as well as spatial variation in soil are difficult to assess without disturbing the system. The most common method of partitioning soil respiration into its components is trenching which entails the roots being cut or girdling where the flow of carbohydrates from the canopy to roots has been isolated by cutting of the phloem. Other methods for determining the contribution of autotrophic (Ra) and heterotrophic (Rh) respiration components in soil CO2 efflux are pulse labelling with 13CO2 or 14CO2 or the natural abundance of 13C and/or 14C isotopes. Also differences in seasonal and short-term temperature response of soil respiration have been used to separate Ra and Rh. We compared the seasonal variation in Ra and Rh using the trenching method and differences between seasonal and short-term temperature responses of soil respiration. I addition, we estimated the vertical variation in soil biological activity using soil CO2 concentration and the natural abundance of 13C and 12C

  15. Adaptation of the Cyanobacterium Anabaena variabilis to Low CO2 Concentration in Their Environment 1

    Science.gov (United States)

    Marcus, Yehouda; Harel, Eitan; Kaplan, Aaron

    1983-01-01

    The rate of adaptation of high CO2 (5% v/v CO2 in air)-grown Anabaena to a low level of CO2 (0.05% v/v in air) was determined as a function of O2 concentration. Exposure of cells to low (2.6%) O2 concentration resulted in an extended lag in the adaptation to low CO2 concentration. The rate of adaptation following the lag was not affected by the concentration of O2. The length of the lag period is markedly affected by the O2/CO2 concentration ratio, indicating that the signal for adaptation to low CO2 may be related to the relative rate of ribulose-1,5-bisphosphate carboxylase/oxygenase activities, rather than to CO2 concentration proper. This suggestion is supported by the observed accumulation of phosphoglycolate following transfer of cells from high to low CO2 concentration. PMID:16662790

  16. The optimal atmospheric CO2 concentration for the growth of winter wheat (Triticum aestivum).

    Science.gov (United States)

    Xu, Ming

    2015-07-20

    This study examined the optimal atmospheric CO2 concentration of the CO2 fertilization effect on the growth of winter wheat with growth chambers where the CO2 concentration was controlled at 400, 600, 800, 1000, and 1200 ppm respectively. I found that initial increase in atmospheric CO2 concentration dramatically enhanced winter wheat growth through the CO2 fertilization effect. However, this CO2 fertilization effect was substantially compromised with further increase in CO2 concentration, demonstrating an optimal CO2 concentration of 889.6, 909.4, and 894.2 ppm for aboveground, belowground, and total biomass, respectively, and 967.8 ppm for leaf photosynthesis. Also, high CO2 concentrations exceeding the optima not only reduced leaf stomatal density, length and conductance, but also changed the spatial distribution pattern of stomata on leaves. In addition, high CO2 concentration also decreased the maximum carboxylation rate (Vc(max)) and the maximum electron transport rate (J(max)) of leaf photosynthesis. However, the high CO2 concentration had little effect on leaf length and plant height. The optimal CO2 fertilization effect found in this study can be used as an indicator in selecting and breeding new wheat strains in adapting to future high atmospheric CO2 concentrations and climate change. Copyright © 2015. Published by Elsevier GmbH.

  17. Effect of CO2 Concentration on Glycine and Serine Formation during Photorespiration 1

    Science.gov (United States)

    Snyder, F. W.; Tolbert, N. E.

    1974-01-01

    Amount and products of photosynthesis during 10 minutes were measured at different 14CO2 concentrations in air. With tobacco (Nicotiana tabacum L. cv. Maryland Mammoth) leaves the percentage of 14C in glycine plus serine was highest (42%) at 0.005% CO2, and decreased with increasing CO2 concentration to 7% of the total at 1% CO2 in air. However, above 0.03% CO2 the total amount of 14C incorporated into the glycine and serine pool was about constant. At 0.005% or 0.03% CO2 the percentage and amount of 14C in sucrose was small but increased greatly at higher CO2 levels as sucrose accumulated as an end product. Relatively similar data were obtained with sugar beet (Beta vulgaris L. cv. US H20) leaves. The results suggest that photorespiration at high CO2 concentration is not inhibited but that CO2 loss from it becomes less significant. PMID:16658736

  18. Silicate dissolution boosts the CO2 concentrations in subduction fluids.

    Science.gov (United States)

    Tumiati, S; Tiraboschi, C; Sverjensky, D A; Pettke, T; Recchia, S; Ulmer, P; Miozzi, F; Poli, S

    2017-09-20

    Estimates of dissolved CO2 in subduction-zone fluids are based on thermodynamic models, relying on a very sparse experimental data base. Here, we present experimental data at 1-3 GPa, 800 °C, and ∆FMQ ≈ -0.5 for the volatiles and solute contents of graphite-saturated fluids in the systems COH, SiO2-COH ( + quartz/coesite) and MgO-SiO2-COH ( + forsterite and enstatite). The CO2 content of fluids interacting with silicates exceeds the amounts measured in the pure COH system by up to 30 mol%, as a consequence of a decrease in water activity probably associated with the formation of organic complexes containing Si-O-C and Si-O-Mg bonds. The interaction of deep aqueous fluids with silicates is a novel mechanism for controlling the composition of subduction COH fluids, promoting the deep CO2 transfer from the slab-mantle interface to the overlying mantle wedge, in particular where fluids are stable over melts.Current estimates of dissolved CO2 in subduction-zone fluids based on thermodynamic models rely on a very sparse experimental data base. Here, the authors show that experimental graphite-saturated COH fluids interacting with silicates at 1-3 GPa and 800 °C display unpredictably high CO2 contents.

  19. Interactions between temperature and intercellular CO2 concentration in controlling leaf isoprene emission rates

    National Research Council Canada - National Science Library

    Monson, Russell K; Neice, Amberly A; Trahan, Nicole A; Shiach, Ian; McCorkel, Joel T; Moore, David J.P

    2016-01-01

    .... Evidence exists from a limited set of past observations that isoprene emission rate (I s ) decreases as a function of increasing atmospheric CO 2 concentration, and that increased temperature suppresses the CO 2 effect...

  20. [Effects of nitrogen fertilization on wheat leaf photosynthesis under elevated atmospheric CO2 concentration].

    Science.gov (United States)

    Yu, Xian-feng; Zhang, Xu-cheng; Guo, Tian-wen; Yu, Jia

    2010-09-01

    In this paper, the effects of nitrogen (N) fertilization on the wheat leaf photosynthesis under long-term elevated atmospheric CO2 concentration (760 micromol x mol(-1)) was studied, based on the measurements of photosynthetic gas exchange parameters and light intensity-photosynthetic rate response curves at jointing stage. Under the long-term elevated atmospheric CO2 concentration, applying sufficient N could increase the wheat leaf photosynthetic rate (Pn), transpiration rate (Tr), and instantaneous water use efficiency (WUEi). Comparing with those under ambient atmospheric CO2 concentration, the Po and WUEi under the elevated atmospheric CO2 concentration increased, while the stomatal conductance (Gs) and intercellular CO2 concentration (Ci) decreased. With the increase of light flux intensity, the Pn and WUEi under the elevated atmospheric CO2 concentration were higher those under ambient atmospheric CO2 concentration, Gs was in adverse, while Ci and Tr had less change. At high fertilization rate of N, the Gs was linearly positively correlated with Pn, Tr, and WUEi, and the Gs and Ci had no correlation with each other under the elevated atmospheric CO2 concentration but negatively correlated under ambient atmospheric CO2 concentration. At low fertilization rate of N, the Gs had no correlations with Pn and WUEi but linearly positively correlated with Ci and Tr. It was suggested that under the elevated atmospheric CO2 concentration, the wheat leaf Pn at low N fertilization rate was limited by non-stomatal factor.

  1. [Dynamic observation, simulation and application of soil CO2 concentration: a review].

    Science.gov (United States)

    Sheng, Hao; Luo, Sha; Zhou, Ping; Li, Teng-Yi; Wang, Juan; Li, Jie

    2012-10-01

    Soil CO2 concentration is the consequences of biological activities in above- and below-ground, and its fluctuation may significantly affect the future atmospheric CO2 concentration and the projected climate change. This paper reviewed the methodologies for measuring the soil CO2 concentration in situ as well as their advantages and disadvantages, analyzed the variation patterns and controlling factors of soil CO2 concentration across the temporal (diurnal, several days, seasonal and inter-annual) and spatial (soil profile, site and landscape) scales, introduced the primary empirical and mechanical models for estimating and predicting soil CO2 concentration, and summarized the applications and constraints of soil CO2 concentration gradient in determining soil respiration. Four research priorities were proposed, i. e., to develop new techniques for collecting and determining the soil CO2 in severe soil conditions (e. g., flooding, lithoso and others), to approach the responses of soil CO2 concentration to weather change and related regulation mechanisms, to strengthen the researches on the spatial heterogeneity of soil CO2 concentration, and to expand the applications of soil CO2 concentration gradient in the measurement of tropical-subtropical soil respiration.

  2. Rising global atmospheric CO2 concentration and implications for crop productivity

    Science.gov (United States)

    There is incontestable evidence that the concentration of atmospheric CO2 is increasing. Regardless of the potential impact of this increase on climate change, CO2 will have a direct effect on plants since it is a primary input for growth. Herein, we discuss relative CO2 responses of C3 and C4 plant...

  3. A simple empirical model estimating atmospheric CO2 background concentrations

    Science.gov (United States)

    Reuter, M.; Buchwitz, M.; Schneising, O.; Heymann, J.; Guerlet, S.; Cogan, A. J.; Bovensmann, H.; Burrows, J. P.

    2012-02-01

    A simple empirical CO2 model (SECM) is presented to estimate column-average dry-air mole fractions of atmospheric CO2 (XCO2) as well as mixing ratio profiles. SECM is based on a simple equation depending on 17 empirical parameters, latitude, and date. The empirical parameters have been determined by least squares fitting to NOAA's (National Oceanic and Atmospheric Administration) assimilation system CarbonTracker version 2010 (CT2010). Comparisons with TCCON (total column carbon observing network) FTS (Fourier transform spectrometer) measurements show that SECM XCO2 agrees quite well with reality. The synthetic XCO2 values have a standard error of 1.39 ppm and systematic station-to-station biases of 0.46 ppm. Typical column averaging kernels of the TCCON FTS, a SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY), and two GOSAT (Greenhouse gases Observing SATellite) XCO2 retrieval algorithms have been used to assess the smoothing error introduced by using SECM profiles instead of CT2010 profiles as a priori. The additional smoothing error amounts to 0.17 ppm for a typical SCIAMACHY averaging kernel and is most times much smaller for the other instruments (e.g. 0.05 ppm for a typical TCCON FTS averaging kernel). Therefore, SECM is well-suited to provide a priori information for state of the art ground-based (FTS) and satellite-based (GOSAT, SCIAMACHY) XCO2 retrievals. Other potential applications are: (i) quick check for obvious retrieval errors (by monitoring the difference to SECM), (ii) near real time processing systems (that cannot make use of models like CT2010 operated in delayed mode), (iii) "CO2 proxy" methods for XCH4 retrievals (as correction for the XCO2 background), (iv) observing system simulation experiments especially for future satellite missions.

  4. Elevated CO2 concentration around alfalfa nodules increases N2 fixation

    Science.gov (United States)

    Fischinger, Stephanie A.; Hristozkova, Marieta; Mainassara, Zaman-Allah; Schulze, Joachim

    2010-01-01

    Nodule CO2 fixation via PEPC provides malate for bacteroids and oxaloacetate for N assimilation. The process is therefore of central importance for efficient nitrogen fixation. Nodule CO2 fixation is known to depend on external CO2 concentration. The hypothesis of the present paper was that nitrogen fixation in alfalfa plants is enhanced when the nodules are exposed to elevated CO2 concentrations. Therefore nodulated plants of alfalfa were grown in a hydroponic system that allowed separate aeration of the root/nodule compartment that avoided any gas leakage to the shoots. The root/nodule compartments were aerated either with a 2500 μl l−1 (+CO2) or zero μl l−1 (–CO2) CO2-containing N2/O2 gas flow (80/20, v/v). Nodule CO2 fixation, nitrogen fixation, and growth were strongly increased in the +CO2 treatment in a 3-week experimental period. More intensive CO2 and nitrogen fixation coincided with higher per plant amounts of amino acids and organic acids in the nodules. Moreover, the concentration of asparagine was increased in both the nodules and the xylem sap. Plants in the +CO2 treatment tended to develop nodules with higher %N concentration and individual activity. In a parallel experiment on plants with inefficient nodules (fix–) the +CO2 treatment remained without effect. Our data support the thesis that nodule CO2 fixation is pivotal for efficient nitrogen fixation. It is concluded that strategies which enhance nodule CO2 fixation will improve nitrogen fixation and nodule formation. Moreover, sufficient CO2 application to roots and nodules is necessary for growth and efficient nitrogen fixation in hydroponic and aeroponic growth systems. PMID:19815686

  5. Carbon dioxide consumption of the microalga Scenedesmus obtusiusculus under transient inlet CO2 concentration variations.

    Science.gov (United States)

    Cabello, Juan; Morales, Marcia; Revah, Sergio

    2017-04-15

    The extensive microalgae diversity offers considerable versatility for a wide range of biotechnological applications in environmental and production processes. Microalgal cultivation is based on CO2 fixation via photosynthesis and, consequently, it is necessary to evaluate, in a short time and reliable way, the effect of the CO2 gas concentration on the consumption rate and establish the tolerance range of different strains and the amount of inorganic carbon that can be incorporated into biomass in order to establish the potential for industrial scale application. Dynamic experiments allow calculating the short-term microalgal photosynthetic activity of strains in photobioreactors. In this paper, the effect of step-changes in CO2 concentration fed to a 20L bubble column photobioreactor on the CO2 consumption rate of Scenedesmus obtusiusculus was evaluated at different operation times. The highest apparent CO2 consumption rate (336μmolm(-2)s(-1) and 5.6% of CO2) was 6530mgCO2gb(-1)d(-1) and it decreased to 222mgCO2gb(-1)d(-1) when biomass concentration increased of 0.5 to 3.1gbL(-1) and 5.6% of CO2 was fed. For low CO2 concentrations (<3.8%) the pH remained close to the optimal value (7.5 and 8). The CO2 consumption rates show that S. obtusiusculus was not limited by CO2 availability for concentrations above of 3.8%. The CO2 mass balance showed that 90% of the C-CO2 transferred was used for S. obtusiusculus growth. Copyright © 2017. Published by Elsevier B.V.

  6. Rising CO2 concentration altered wheat grain proteome and flour rheological characteristics.

    Science.gov (United States)

    Fernando, Nimesha; Panozzo, Joe; Tausz, Michael; Norton, Robert; Fitzgerald, Glenn; Khan, Alamgir; Seneweera, Saman

    2015-03-01

    Wheat cv. H45 was grown under ambient CO2 concentration and Free Air CO2 Enrichment (FACE; e[CO2], ∼550 μmol CO2 mol(-1)). The effect of FACE on wheat grain proteome and associated changes in the flour rheological properties was investigated. A comparative proteomic analysis was performed using 2-D-DIGE followed by MALDI/TOF-MS. Total grain protein concentration was decreased by 9% at e[CO2]. Relative abundance of three high molecular weight glutenin sub units (HMW-GS) were decreased at e[CO2]. In contrast, relative abundance of serpins Z1C and 1-Cys peroxiredoxin was increased at e[CO2]. Elevated [CO2] also decreased the bread volume (by 11%) and dough strength (by 7%) while increased mixing time. However, dough extensibility and dough stability were unchanged at elevated [CO2]. These findings suggest that e[CO2] has a major impact on gluten protein concentration which is associated lower bread quality at e[CO2]. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Phosphorus supply drives nonlinear responses of cottonwood (Populus deltoides) to increases in CO2 concentration from glacial to future concentrations.

    Science.gov (United States)

    Lewis, James D; Ward, Joy K; Tissue, David T

    2010-07-01

    *Despite the importance of nutrient availability in determining plant responses to climate change, few studies have addressed the interactive effects of phosphorus (P) supply and rising atmospheric CO(2) concentration ([CO(2)]) from glacial to modern and future concentrations on tree seedling growth. *The objective of our study was to examine interactive effects across a range of P supply (six concentrations from 0.004 to 0.5 mM) and [CO(2)] (200 (glacial), 350 (modern) and 700 (future) ppm) on growth, dry mass allocation, and light-saturated photosynthesis (A(sat)) in Populus deltoides (cottonwood) seedlings grown in well-watered conditions. *Increasing [CO(2)] from glacial to modern concentrations increased growth by 25% across P treatments, reflecting reduced [CO(2)] limitations to photosynthesis and increased A(sat). Conversely, the growth response to future [CO(2)] was very sensitive to P supply. Future [CO(2)] increased growth by 80% in the highest P supply but only by 7% in the lowest P supply, reflecting P limitations to A(sat), leaf area and leaf area ratio (LAR), compared with modern [CO(2)]. *Our results suggest that future [CO(2)] will minimally increase cottonwood growth in low-P soils, but in high-P soils may stimulate production to a greater extent than predicted based on responses to past increases in [CO(2)]. Our results indicate that the capacity for [CO(2)] stimulation of cottonwood growth does not decline as [CO(2)] rises from glacial to future concentrations.

  8. Effects of atmospheric CO2 concentration, irradiance, and soil nitrogen availability on leaf photosynthetic traits of Polygonum sachalinense around natural CO2 springs in northern Japan.

    Science.gov (United States)

    Osada, Noriyuki; Onoda, Yusuke; Hikosaka, Kouki

    2010-09-01

    Long-term exposure to elevated CO2 concentration will affect the traits of wild plants in association with other environmental factors. We investigated multiple effects of atmospheric CO2 concentration, irradiance, and soil N availability on the leaf photosynthetic traits of a herbaceous species, Polygonum sachalinense, growing around natural CO2 springs in northern Japan. Atmospheric CO2 concentration and its interaction with irradiance and soil N availability affected several leaf traits. Leaf mass per unit area increased and N per mass decreased with increasing CO2 and irradiance. Leaf N per area increased with increasing soil N availability at higher CO2 concentrations. The photosynthetic rate under growth CO2 conditions increased with increasing irradiance and CO2, and with increasing soil N at higher CO2 concentrations. The maximal velocity of ribulose 1,5-bisphosphate carboxylation (V (cmax)) was affected by the interaction of CO2 and soil N, suggesting that down-regulation of photosynthesis at elevated CO2 was more evident at lower soil N availability. The ratio of the maximum rate of electron transport to V (cmax) (J (max)/V (cmax)) increased with increasing CO2, suggesting that the plants used N efficiently for photosynthesis at high CO2 concentrations by changes in N partitioning. To what extent elevated CO2 influenced plant traits depended on other environmental factors. As wild plants are subject to a wide range of light and nutrient availability, our results highlight the importance of these environmental factors when the effects of elevated CO2 on plants are evaluated.

  9. Impact of elevated CO2 concentration under three soil water levels on growth of Cinnamomum camphora *

    Science.gov (United States)

    Zhao, Xing-Zheng; Wang, Gen-Xuan; Shen, Zhu-Xia; Zhang, Hao; Qiu, Mu-Qing

    2006-01-01

    Forest plays very important roles in global system with about 35% land area producing about 70% of total land net production. It is important to consider both elevated CO2 concentrations and different soil moisture when the possible effects of elevated CO2 concentration on trees are assessed. In this study, we grew Cinnamomum camphora seedlings under two CO2 concentrations (350 μmol/mol and 500 μmol/mol) and three soil moisture levels [80%, 60% and 40% FWC (field water capacity)] to focus on the effects of exposure of trees to elevated CO2 on underground and aboveground plant growth, and its dependence on soil moisture. The results indicated that high CO2 concentration has no significant effects on shoot height but significantly impacts shoot weight and ratio of shoot weight to height under three soil moisture levels. The response of root growth to CO2 enrichment is just reversed, there are obvious effects on root length growth, but no effects on root weight growth and ratio of root weight to length. The CO2 enrichment decreased 20.42%, 32.78%, 20.59% of weight ratio of root to shoot under 40%, 60% and 80% FWC soil water conditions, respectively. And elevated CO2 concentration significantly increased the water content in aboveground and underground parts. Then we concluded that high CO2 concentration favours more tree aboveground biomass growth than underground biomass growth under favorable soil water conditions. And CO2 enrichment enhanced lateral growth of shoot and vertical growth of root. The responses of plants to elevated CO2 depend on soil water availability, and plants may benefit more from CO2 enrichment with sufficient water supply. PMID:16532530

  10. Growth under elevated atmospheric CO(2) concentration accelerates leaf senescence in sunflower (Helianthus annuus L.) plants.

    Science.gov (United States)

    de la Mata, Lourdes; Cabello, Purificación; de la Haba, Purificación; Agüera, Eloísa

    2012-09-15

    Some morphogenetic and metabolic processes were sensitive to a high atmospheric CO(2) concentration during sunflower primary leaf ontogeny. Young leaves of sunflower plants growing under elevated CO(2) concentration exhibited increased growth, as reflected by the high specific leaf mass referred to as dry weight in young leaves (16 days). The content of photosynthetic pigments decreased with leaf development, especially in plants grown under elevated CO(2) concentrations, suggesting that high CO(2) accelerates chlorophyll degradation, and also possibly leaf senescence. Elevated CO(2) concentration increased the oxidative stress in sunflower plants by increasing H(2)O(2) levels and decreasing activity of antioxidant enzymes such as catalase and ascorbate peroxidase. The loss of plant defenses probably increases the concentration of reactive oxygen species in the chloroplast, decreasing the photosynthetic pigment content as a result. Elevated CO(2) concentration was found to boost photosynthetic CO(2) fixation, especially in young leaves. High CO(2) also increased the starch and soluble sugar contents (glucose and fructose) and the C/N ratio during sunflower primary leaf development. At the beginning of senescence, we observed a strong increase in the hexoses to sucrose ratio that was especially marked at high CO(2) concentration. These results indicate that elevated CO(2) concentration could promote leaf senescence in sunflower plants by affecting the soluble sugar levels, the C/N ratio and the oxidative status during leaf ontogeny. It is likely that systemic signals produced in plants grown with elevated CO(2), lead to early senescence and a higher oxidation state of the cells of these plant leaves. Copyright © 2012 Elsevier GmbH. All rights reserved.

  11. Drought × CO2 interactions in trees: a test of the low-intercellular CO2 concentration (Ci ) mechanism.

    Science.gov (United States)

    Kelly, Jeff W G; Duursma, Remko A; Atwell, Brian J; Tissue, David T; Medlyn, Belinda E

    2016-03-01

    Models of tree responses to climate typically project that elevated atmospheric CO2 concentration (eCa ) will reduce drought impacts on forests. We tested one of the mechanisms underlying this interaction, the 'low Ci effect', in which stomatal closure in drought conditions reduces the intercellular CO2 concentration (Ci ), resulting in a larger relative enhancement of photosynthesis with eCa , and, consequently, a larger relative biomass response. We grew two Eucalyptus species of contrasting drought tolerance at ambient and elevated Ca for 6-9 months in large pots maintained at 50% (drought) and 100% field capacity. Droughted plants did not have significantly lower Ci than well-watered plants, which we attributed to long-term changes in leaf area. Hence, there should not have been an interaction between eCa and water availability on biomass, and we did not detect one. The xeric species did have higher Ci than the mesic species, indicating lower water-use efficiency, but both species exhibited similar responses of photosynthesis and biomass to eCa , owing to compensatory differences in the photosynthetic response to Ci . Our results demonstrate that long-term acclimation to drought, and coordination among species traits may be important for predicting plant responses to eCa under low water availability. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  12. Acclimation of nitrogen uptake capacity of rice to elevated atmospheric CO2 concentration

    Science.gov (United States)

    Shimono, Hiroyuki; Bunce, James A.

    2009-01-01

    Background and Aims Nitrogen (N) is a major factor affecting yield gain of crops under elevated atmospheric carbon dioxide concentrations [CO2]. It is well established that elevated [CO2] increases root mass, but there are inconsistent reports on the effects on N uptake capacity per root mass. In the present study, it was hypothesized that the responses of N uptake capacity would change with the duration of exposure to elevated [CO2]. Methods The hypothesis was tested by measuring N uptake capacity in rice plants exposed to long-term and short-term [CO2] treatments at different growth stages in plants grown under non-limiting N conditions in hydroponic culture. Seasonal changes in photosynthesis rate and transpiration rate were also measured. Key Results In the long-term [CO2] study, leaf photosynthetic responses to intercellular CO2 concentration (Ci) were not affected by elevated [CO2] before the heading stage, but the initial slope in this response was decreased by elevated [CO2] at the grain-filling stage. Nitrate and ammonium uptake capacities per root dry weight were not affected by elevated [CO2] at panicle initiation, but thereafter they were reduced by elevated [CO2] by 31–41 % at the full heading and mid-ripening growth stages. In the short-term study (24 h exposures), elevated [CO2] enhanced nitrate and ammonium uptake capacities at the early vegetative growth stage, but elevated [CO2] decreased the uptake capacities at the mid-reproductive stage. Conclusions This study showed that N uptake capacity was downregulated under long-term exposure to elevated [CO2] and its response to elevated [CO2] varied greatly with growth stage. PMID:18952623

  13. Technology advancement of the electrochemical CO2 concentrating process

    Science.gov (United States)

    Schubert, F. H.; Heppner, D. B.; Hallick, T. M.; Woods, R. R.

    1979-01-01

    Two multicell, liquid-cooled, advanced electrochemical depolarized carbon dioxide concentrator modules were fabricated. The cells utilized advanced, lightweight, plated anode current collectors, internal liquid cooling and lightweight cell frames. Both were designed to meet the carbon dioxide removal requirements of one-person, i.e., 1.0 kg/d (2.2 lb/d).

  14. The influence of co2 + concentration on the electrodeposition of ...

    African Journals Online (AJOL)

    In this work we have done an experimental study of Zinc- Nickel composite coatings. For this, the influence of the cobalt concentration was the principal object in order to improve the resistance of the corrosion of the coatings, which has been made by electroplating on steel substrates previously treated, have been studied ...

  15. Salt concentrations during water production resulting from CO2 storage

    DEFF Research Database (Denmark)

    Walter, Lena; Class, Holger; Binning, Philip John

    2014-01-01

    present in the saline aquifer. The brine can be displaced over large areas and can reach shallower groundwater resources. High salt concentrations could lead to a degradation of groundwater quality. For water suppliers the most important information is whether and how much salt is produced at a water...... production well. In this approach the salt concentrations at water production wells depending on different parameters are determined for the assumption of a 2D model domain accounting for groundwater flow. Recognized ignorance resulting from grid resolution is qualitatively studied and statistical...... uncertainty is investigated for three parameters: the well distance, the water production rate, and the permeability of the aquifer. One possible way of estimating statistical uncertainties and providing probabilities is performing numerical Monte Carlo (MC) simulations. The MC approach is computationally...

  16. Genes responsive to elevated CO2 concentrations in triploid white poplar and integrated gene network analysis.

    Directory of Open Access Journals (Sweden)

    Juanjuan Liu

    Full Text Available BACKGROUND: The atmospheric CO2 concentration increases every year. While the effects of elevated CO2 on plant growth, physiology and metabolism have been studied, there is now a pressing need to understand the molecular mechanisms of how plants will respond to future increases in CO2 concentration using genomic techniques. PRINCIPAL FINDINGS: Gene expression in triploid white poplar ((Populus tomentosa ×P. bolleana ×P. tomentosa leaves was investigated using the Affymetrix poplar genome gene chip, after three months of growth in controlled environment chambers under three CO2 concentrations. Our physiological findings showed the growth, assessed as stem diameter, was significantly increased, and the net photosynthetic rate was decreased in elevated CO2 concentrations. The concentrations of four major endogenous hormones appeared to actively promote plant development. Leaf tissues under elevated CO2 concentrations had 5,127 genes with different expression patterns in comparison to leaves under the ambient CO2 concentration. Among these, 8 genes were finally selected for further investigation by using randomized variance model corrective ANOVA analysis, dynamic gene expression profiling, gene network construction, and quantitative real-time PCR validation. Among the 8 genes in the network, aldehyde dehydrogenase and pyruvate kinase were situated in the core and had interconnections with other genes. CONCLUSIONS: Under elevated CO2 concentrations, 8 significantly changed key genes involved in metabolism and responding to stimulus of external environment were identified. These genes play crucial roles in the signal transduction network and show strong correlations with elevated CO2 exposure. This study provides several target genes, further investigation of which could provide an initial step for better understanding the molecular mechanisms of plant acclimation and evolution in future rising CO2 concentrations.

  17. Co-ordination in morphological leaf traits of early diverging angiosperms is maintained following exposure to experimental palaeo-atmospheric conditions of sub-ambient O2 and elevated CO2

    Directory of Open Access Journals (Sweden)

    Christiana Evans-Fitz.Gerald

    2016-09-01

    Full Text Available In order to be successful in a given environment a plant should invest in a vein network and stomatal distribution that ensures balance between both water supply and demand. Vein density (Dv and stomatal density (SD have been shown to be strongly positively correlated in response to a range of environmental variables in more recently evolved plant species, but the extent of this relationship has not been confirmed in earlier diverging plant lineages. In order to examine the effect of a changing atmosphere on the relationship between Dv and SD, five early-diverging plant species representing two different reproductive plant grades were grown for seven months in a palaeo-treatment comprising an O2:CO2 ratio that has occurred multiple times throughout plant evolutionary history. Results show a range of species-specific Dv and SD responses to the palaeo-treatment, however we show that the strong relationship between Dv and SD under modern ambient atmospheric composition is maintained following exposure to the palaeo-treatment. This suggests strong inter-specific co-ordination between vein and stomatal traits for our study species even under relatively extreme environmental change. This co-ordination supports existing plant function proxies that use the distance between vein endings and stomata (Dm to infer plant palaeo-physiology.

  18. [Diurnal and seasonal variations of surface atmospheric CO2 concentration in the river estuarine marsh].

    Science.gov (United States)

    Zhang, Lin-Hai; Tong, Chuan; Zeng, Cong-Sheng

    2014-03-01

    Characteristics of diurnal and seasonal variations of surface atmospheric CO2 concentration were analyzed in the Minjiang River estuarine marsh from December 2011 to November 2012. The results revealed that both the diurnal and seasonal variation of surface atmospheric CO2 concentration showed single-peak patterns, with the valley in the daytime and the peak value at night for the diurnal variations, and the maxima in winter and minima in summer for the seasonal variation. Diurnal amplitude of CO2 concentration varied from 16.96 micromol x mol(-1) to 38.30 micromol x mol(-1). The seasonal averages of CO2 concentration in spring, summer, autumn and winter were (353.74 +/- 18.35), (327.28 +/- 8.58), (354.78 +/- 14.76) and (392.82 +/- 9.71) micromol x mol(-1), respectively, and the annual mean CO2 concentration was (357.16 +/- 26.89) micromol x mol(-1). The diurnal CO2 concentration of surface atmospheric was strongly negatively correlated with temperature, wind speed, photosynthetically active radiation and total solar radiation (P < 0.05). The diurnal concentration of CO2 was negatively related with tidal level in January, but significantly positively related in July.

  19. [Effects of elevated rhizosphere CO2 concentration on the photosynthetic characteristics, yield, and quality of muskmelon].

    Science.gov (United States)

    Liu, Yi-Ling; Sun, Zhou-Ping; Li, Tian-Lai; Gu, Feng-Ying; He, Yu

    2013-10-01

    By using aeroponics culture system, this paper studied the effects of elevated rhizosphere CO2 concentration on the leaf photosynthesis and the fruit yield and quality of muskmelon during its anthesis-fruiting period. In the fruit development period of muskmelon, as compared with those in the control (350 microL CO2 x L (-1)), the leaf chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and the maximal photochemical efficiency of PS II (Fv/Fm) in treatments 2500 and 5000 microL CO2 x L(-1) decreased to some extents, but the stomatal limitation value (Ls) increased significantly, and the variation amplitudes were larger in treatment 5000 microL CO2 x L(-1) than in treatment 2500 microL CO2 x L(-1). Under the effects of elevated rhizosphere CO2 concentration, the fruit yield per plant and the Vc and soluble sugar contents in fruits decreased markedly, while the fruit organic acid content was in adverse. It was suggested that when the rhizosphere CO2 concentration of muskmelon during its anthesis-fruiting period reached to 2500 microL x L(-1), the leaf photosynthesis and fruit development of muskmelon would be depressed obviously, which would result in the decrease of fruit yield and quality of muskmelon.

  20. Simulation of CO 2 concentrations at Tsukuba tall tower using WRF ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 125; Issue 1. Simulation of CO2 concentrations at Tsukuba tall tower using WRF-CO2 tracer transport model. Srabanti Ballav Prabir K Patra Yousuke Sawa Hidekazu Matsueda Ahoro Adachi Shigeru Onogi Masayuki Takigawa Utpal K De. Volume 125 Issue 1 ...

  1. Effects of Elevated CO2 Concentration on Photosynthesis and Respiration of Populus Deltodies

    Science.gov (United States)

    Anderson, Angela M.

    1998-01-01

    To determine how increased atmospheric CO2 will affect the physiology of cottonwood trees, cuttings of the cloned Populus deltodies [cottonwood] were grown in open-top chambers containing ambient or elevated CO2 concentration. The control treatment was maintained at ambient Biosphere 2 atmospheric CO2 (c. 450 +/- 50 micro l/l), and elevated CO2 treatment was maintained at approximately double ambient Biosphere 2 atmospheric CO2 (c. 1000 +/- 50 micro l/l). The effects of elevated CO2 on leaf photosynthesis, and stomatal conductance were measured. The cottonwoods exposed to CO2 enrichment showed no significant indication of photosynthetic down-regulation. There was no significant difference in the maximum assimilation rate between the treatment and the control (P less than 0.24). The CO2 enriched treatment showed a decreased stomatal conductance of 15% (P less than 0.03). The elevated CO2 concentrated atmosphere had an effect on the respiration rates of the plants; the compensation point of the treatment was on average 13% higher than the control (P less than 0.01).

  2. [Effects of elevated atmospheric CO2 concentration on mung bean leaf photosynthesis and chlorophyll fluorescence parameters].

    Science.gov (United States)

    Hao, Xing-yu; Han, Xue; Li, Ping; Yang, Hong-bin; Lin, Er-da

    2011-10-01

    By using free air CO2 enrichment (FACE) system, a pot experiment under field condition was conducted to study the effects of elevated CO2 concentration (550 +/- 60 micromol mol(-1)) on the leaf photosynthesis and chlorophyll fluorescence parameters of mung bean. Comparing with the control (CO2 concentration averagely 389 +/- 40 micromol mol(-1)), elevated CO2 concentration increased the leaf intercellular CO2 concentration (Ci) and net photosynthesis rate (P(n)) at flowering and pod growth stage by 9.8% and 11.7%, decreased the stomatic conductance (G(s)) and transpiration rate (T(r)) by 32.0% and 24.6%, respectively, and increased the water use efficiency (WUE) by 83.5%. Elevated CO2 concentration had lesser effects on the minimal fluorescence (F0), maximal fluorescence (F(m)), variable fluorescence (F(v)), ratio of variable fluorescence to minimal fluorescence (F(v)/F0), and ratio of variable fluorescence to maximal fluorescence (F(v)/F(m)) at bud stage, but increased the F0 at pod filling stage by 19.1% and decreased the Fm, F(v), F(v)/F0, and F(v)/F(m) by 9.0%, 14.3%, 25.8% , and 6.2%, respectively. These results suggested that elevated CO2 concentration could damage the structure of leaf photosystem II and consequently decrease the leaf photosynthetic capacity in the late growth phase of mung bean.

  3. Experimental and CFD modelling for thermal comfort and CO2 concentration in office building

    Science.gov (United States)

    Kabrein, H.; Hariri, A.; Leman, A. M.; Yusof, M. Z. M.; Afandi, A.

    2017-09-01

    Computational fluid dynamic CFD was used for simulating air flow, indoor air distribution and contamination concentration. Gases pollution and thermal discomfort affected occupational health and productivity of work place. The main objectives of this study are to investigate the impact of air change rate in CO2 concentration and to estimate the profile of CO2 concentration in the offices building. The thermal comfort and gases contamination are investigated by numerical analysis CFD which was validated by experiment. Thus the air temperature, air velocity and CO2 concentration were measured at several points in the chamber with four occupants. Comparing between experimental and numerical results showed good agreement. In addition, the CO2 concentration around human recorded high, compared to the other area. Moreover, the thermal comfort in this study is within the ASHRAE standard 55-2004.

  4. Elevated CO2 concentration impacts cell wall polysaccharide composition of green microalgae of the genus Chlorella.

    Science.gov (United States)

    Cheng, Y-S; Labavitch, J M; VanderGheynst, J S

    2015-01-01

    The effect of CO2 concentration on the relative content of starch, lipid and cell wall carbohydrates in microalgal biomass was investigated for the four following Chlorella strains: C. vulgaris (UTEX 259), C. sorokiniana (UTEX 2805), C. minutissima (UTEX 2341) and C. variabilis (NC64A). Each strain had a different response to CO2 concentration. The starch content was higher in UTEX259 and NC64A cultured with 2% CO2 in the air supply than in cells cultured with ca. 0·04% CO2 (ambient air), while starch content was not affected for UTEX 2805 and UTEX 2341. The lipid content was higher in Chlorella minutissima UTEX 2341 cultured in 2% CO2 than in cells cultured in ambient air, but was unchanged for the other three strains. All four Chlorella strains tended to have a higher percentage of uronic acids and lower percentage of neutral sugars in their cell wall polysaccharide complement when grown with 2% CO2 supply. Although the percentage of neutral sugars in the cell walls varied with CO2 concentration, the relative proportions of different neutral sugar constituents remained constant for both CO2 conditions. The results demonstrate the importance of considering the effects of CO2 on the cell wall carbohydrate composition of microalgae. Microalgae have the potential to produce products that will reduce society's reliance on fossil fuels and address challenges related to food and feed production. An overlooked yet industrially relevant component of microalgae are their cell walls. Cell wall composition affects cell flocculation and the recovery of intracellular products. In this study, we show that increasing CO2 level results in greater cell wall polysaccharide and uronic acid content in the cell walls of three strains of microalgae. The results have implications on the management of systems for the capture of CO2 and production of fuels, chemicals and food from microalgae. © 2014 The Society for Applied Microbiology.

  5. Trace and low concentration co2 removal methods and apparatus utilizing metal organic frameworks

    KAUST Repository

    Eddaoudi, Mohamed

    2016-03-10

    In general, this disclosure describes techniques for removing trace and low concentration CO2 from fluids using SIFSIX-n-M MOFs, wherein n is at least two and M is a metal. In some embodiments, the metal is zinc or copper. Embodiments include devices comprising SIFSIX-n-M MOFs for removing CO2 from fluids. In particular, embodiments relate to devices and methods utilizing SIFSIX-n-M MOFs for removing CO2 from fluids, wherein CO2 concentration is trace. Methods utilizing SIFSIX-n-M MOFs for removing CO2 from fluids can occur in confined spaces. SIFSIX-n-M MOFs can comprise bidentate organic ligands. In a specific embodiment, SIFSIX-n-M MOFs comprise pyrazine or dipryidilacetylene ligands.

  6. Land plants equilibrate O2 and CO2 concentrations in the atmosphere.

    Science.gov (United States)

    Igamberdiev, Abir U; Lea, Peter J

    2006-02-01

    The role of land plants in establishing our present day atmosphere is analysed. Before the evolution of land plants, photosynthesis by marine and fresh water organisms was not intensive enough to deplete CO(2) from the atmosphere, the concentration of which was more than the order of magnitude higher than present. With the appearance of land plants, the exudation of organic acids by roots, following respiratory and photorespiratory metabolism, led to phosphate weathering from rocks thus increasing aquatic productivity. Weathering also replaced silicates by carbonates, thus decreasing the atmospheric CO(2) concentration. As a result of both intensive photosynthesis and weathering, CO(2 )was depleted from the atmosphere down to low values approaching the compensation point of land plants. During the same time period, the atmospheric O(2) concentration increased to maximum levels about 300 million years ago (Permo-Carboniferous boundary), establishing an O(2)/CO(2) ratio above 1000. At this point, land plant productivity and weathering strongly decreased, exerting negative feedback on aquatic productivity. Increased CO(2) concentrations were triggered by asteroid impacts and volcanic activity and in the Mesozoic era could be related to the gymnosperm flora with lower metabolic and weathering rates. A high O(2)/CO(2) ratio is metabolically linked to the formation of citrate and oxalate, the main factors causing weathering, and to the production of reactive oxygen species, which triggered mutations and stimulated the evolution of land plants. The development of angiosperms resulted in a decrease in CO(2) concentration during the Cenozoic era, which finally led to the glacial-interglacial oscillations in the Pleistocene epoch. Photorespiration, the rate of which is directly related to the O(2)/CO(2) ratio, due to the dual function of Rubisco, may be an important mechanism in maintaining the limits of O(2) and CO(2) concentrations by restricting land plant productivity

  7. CARVE: CH4, CO2, and CO Atmospheric Concentrations, CARVE Tower, Alaska, 2012-2014

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides hourly atmospheric concentrations of methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) as mole fractions, from January 2012 to...

  8. CARVE: Monthly Atmospheric CO2 Concentrations (2009-2013) and Modeled Fluxes, Alaska

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports monthly averages of atmospheric CO2 concentration from satellite and airborne observations between 2009 and 2013 and simulated present and...

  9. Phenotypic Plasticity Conditions the Response of Soybean Seed Yield to Elevated Atmospheric CO2 Concentration.

    Science.gov (United States)

    Kumagai, Etsushi; Aoki, Naohiro; Masuya, Yusuke; Shimono, Hiroyuki

    2015-11-01

    Selection for cultivars with superior responsiveness to elevated atmospheric CO2 concentrations (eCO2) is a powerful option for boosting crop productivity under future eCO2. However, neither criteria for eCO2 responsiveness nor prescreening methods have been established. The purpose of this study was to identify traits responsible for eCO2 responsiveness of soybean (Glycine max). We grew 12 Japanese and U.S. soybean cultivars that differed in their maturity group and determinacy under ambient CO2 and eCO2 for 2 years in temperature gradient chambers. CO2 elevation significantly increased seed yield per plant, and the magnitude varied widely among the cultivars (from 0% to 62%). The yield increase was best explained by increased aboveground biomass and pod number per plant. These results suggest that the plasticity of pod production under eCO2 results from biomass enhancement, and would therefore be a key factor in the yield response to eCO2, a resource-rich environment. To test this hypothesis, we grew the same cultivars at low planting density, a resource-rich environment that improved the light and nutrient supplies by minimizing competition. Low planting density significantly increased seed yield per plant, and the magnitude ranged from 5% to 105% among the cultivars owing to increased biomass and pod number per plant. The yield increase due to low-density planting was significantly positively correlated with the eCO2 response in both years. These results confirm our hypothesis and suggest that high plasticity of biomass and pod production at a low planting density reveals suitable parameters for breeding to maximize soybean yield under eCO2. © 2015 American Society of Plant Biologists. All Rights Reserved.

  10. Impacts of CO2 concentration on growth, lipid accumulation, and carbon-concentrating-mechanism-related gene expression in oleaginous Chlorella.

    Science.gov (United States)

    Fan, Jianhua; Xu, Hui; Luo, Yuanchan; Wan, Minxi; Huang, Jianke; Wang, Weiliang; Li, Yuanguang

    2015-03-01

    Biodiesel production by microalgae with photosynthetic CO2 biofixation is thought to be a feasible way in the field of bioenergy and carbon emission reduction. Knowledge of the carbon-concentrating mechanism plays an important role in improving microalgae carbon fixation efficiency. However, little information is available regarding the dramatic changes of cells suffered upon different environmental factors, such as CO2 concentration. The aim of this study was to investigate the growth, lipid accumulation, carbon fixation rate, and carbon metabolism gene expression under different CO2 concentrations in oleaginous Chlorella. It was found that Chlorella pyrenoidosa grew well under CO2 concentrations ranging from 1 to 20 %. The highest biomass and lipid productivity were 4.3 g/L and 107 mg/L/day under 5 % CO2 condition. Switch from high (5 %) to low (0.03 %, air) CO2 concentration showed significant inhibitory effect on growth and CO2 fixation rate. The amount of the saturated fatty acids was increased obviously along with the transition. Low CO2 concentration (0.03 %) was suitable for the accumulation of saturated fatty acids. Reducing the CO2 concentration could significantly decrease the polyunsaturated degree in fatty acids. Moreover, the carbon-concentrating mechanism-related gene expression revealed that most of them, especially CAH2, LCIB, and HLA3, had remarkable change after 1, 4, and 24 h of the transition, which suggests that Chlorella has similar carbon-concentrating mechanism with Chlamydomonas reinhardtii. The findings of the present study revealed that C. pyrenoidosa is an ideal candidate for mitigating CO2 and biodiesel production and is appropriate as a model for mechanism research of carbon sequestration.

  11. Responses of the marine diatom Thalassiosira pseudonana to changes in CO2 concentration: a proteomic approach.

    Science.gov (United States)

    Clement, Romain; Lignon, Sabrina; Mansuelle, Pascal; Jensen, Erik; Pophillat, Matthieu; Lebrun, Regine; Denis, Yann; Puppo, Carine; Maberly, Stephen C; Gontero, Brigitte

    2017-02-09

    The concentration of CO2 in many aquatic systems is variable, often lower than the KM of the primary carboxylating enzyme Rubisco, and in order to photosynthesize efficiently, many algae operate a facultative CO2 concentrating mechanism (CCM). Here we measured the responses of a marine diatom, Thalassiosira pseudonana, to high and low concentrations of CO2 at the level of transcripts, proteins and enzyme activity. Low CO2 caused many metabolic pathways to be remodeled. Carbon acquisition enzymes, primarily carbonic anhydrase, stress, degradation and signaling proteins were more abundant while proteins associated with nitrogen metabolism, energy production and chaperones were less abundant. A protein with similarities to the Ca(2+)/ calmodulin dependent protein kinase II_association domain, having a chloroplast targeting sequence, was only present at low CO2. This protein might be a specific response to CO2 limitation since a previous study showed that other stresses caused its reduction. The protein sequence was found in other marine diatoms and may play an important role in their response to low CO2 concentration.

  12. Canopy CO2 exchange of sugar beet under different CO2 concentrations and nitrogen supply: results from a free-air CO2 enrichment study.

    Science.gov (United States)

    Burkart, S; Manderscheid, R; Weigel, H-J

    2009-11-01

    Sugar beet (Beta vulgaris ssp. altissima Döll) was grown in the field under free-air CO(2) enrichment (FACE, 550 ppm) and different nitrogen (N) supply (2001: 126 (N100) and 63 kg.ha(-1) (N50); 2004: 156 (N100) and 75 kg.ha(-1)) during two crop rotations. Canopy CO(2) exchange rates (CCER) were measured during the main growth phase (leaf area index > or =2) using a dynamic chamber system. Canopy CO(2) exchange data were analysed with respect to treatment effects on seasonal means and light use efficiency and light response characteristics. CO(2) enrichment enhanced CCER throughout the season. However, in both years, CCER declined after the second half of August independent of radiation and [CO(2)]. Elevated [CO(2)] strongly stimulated CCER on a seasonal basis, whereas the reduction of CCER caused by low N was below 10% and not significant. There were no effects of N on daily radiation use efficiency of carbon gain calculated from CCER data, but a strong enhancement by CO(2) enrichment. CCER closely tracked diurnal variations in incident photosynthetic photon flux density (PPFD, mumol.m(-2).s(-1)). The relationship between CCER and incident PPFD was curvilinear. In both seasons, initial slopes and maximum rates (CCER(max)) were determined from two 6-day periods using these relationships. The first period was measured after canopy closure (first half of July) and the second in the second half of August. In the first period, elevated [CO(2)] increased the initial slopes. Low N supply affected neither the initial slopes nor their response to elevated [CO(2)] in either period. In contrast to initial slopes, N stress limited the [CO(2)] response of CCER(max) in the first period. In the second period, however, this interaction of [CO(2)] and N on CCER(max) was completely dominated by a general decline of CCER(max) whereas no general decline of the initial slopes occurred in the second period. This response of light response parameters to [CO(2)] and N suggests that, in

  13. [Variation of CO2 concentration in solar greenhouse in Northern China].

    Science.gov (United States)

    Wei, Min; Xing, Yuxian; Wang, Xiufeng; Ma, Hong

    2003-03-01

    The variation of CO2 concentration in winter-spring cultivated solar greenhouse in northern China was studied. The diurnal change of CO2 concentration showed an irregular 'U' shape in most case, the maximum value appeared prior to unveiling straw mat in the morning, and the minimum between 12:00 and 14:00 PM. Sometimes, an irregular 'W' shape curve with two valleys was also observed, with the first one appeared prior to the ventilation at noon, and the second occurred between 15:00-16:30 PM. During the period of winter-spring cultivation, the daily maximum concentration of CO2 in solar greenhouse decreased gradually, while the daily minimum concentration and daytime average concentration dropped first, then went up. At the same time, the time of CO2 depletion lasted longer and longer. In December, CO2 depletion happened 2.1-3.1 hours after morning unveiling. In the next March, however, it moved up to 0.6-1.1 hours after unveiling in the morning. At daytime, both during and after ventilation, solar greenhouse often showed CO2 depletion. The period of CO2 depletion extended from 4-5.8 hours per day in December to 8-8.5 hours per day in March of next year. The spacial distribution of CO2 concentrations within the greenhouse showed that in the morning and in the evening, the order was the front > the middle > the back, and the ground > the canopy > the upper, and at midday, the order was the front the upper > the canopy. Photon flux density was the most important environmental factor affecting CO2 concentration in greenhouse. Ventilation did not avoided CO2 depletion. Canopy photosynthetic rate and soil respiratory rate were measured at different growth stages of tomato. At seedling stage, CO2 concentration in greenhouse was higher than that outside, due to the vigorous soil respiration and lower canopy photosynthetic rate. But at fruiting stage, severe CO2 depletion occurred because of stronger canopy photosynthesis and weak soil respiration.

  14. A 2-Micron Pulsed Integrated Path Differential Absorption Lidar Development For Atmospheric CO2 Concentration Measurements

    Science.gov (United States)

    Yu, Jirong; Petros, Mulugeta; Reithmaier, Karl; Bai, Yingxin; Trieu, Bo C.; Refaat, Tamer F.; Kavaya, Michael J.; Singh, Upendra N.

    2012-01-01

    A 2-micron pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement.

  15. A chloroplast pump model for the CO2 concentrating mechanism in the diatom Phaeodactylum tricornutum.

    Science.gov (United States)

    Hopkinson, Brian M

    2014-09-01

    Prior analysis of inorganic carbon (Ci) fluxes in the diatom Phaeodactylum tricornutum has indicated that transport of Ci into the chloroplast from the cytoplasm is the major Ci flux in the cell and the primary driving force for the CO2 concentrating mechanism (CCM). This flux drives the accumulation of Ci in the chloroplast stroma and generates a CO2 deficit in the cytoplasm, inducing CO2 influx into the cell. Here, the "chloroplast pump" model of the CCM in P. tricornutum is formalized and its consistency with data on CO2 and HCO3 (-) uptake rates, carbonic anhydrase (CA) activity, intracellular Ci concentration, intracellular pH, and RubisCO characteristics is assessed. The chloroplast pump model can account for the major features of the data. Analysis of photosynthetic and Ci uptake rates as a function of external Ci concentration shows that the model has the most difficulty obtaining sufficiently low cytoplasmic CO2 concentrations to support observed CO2 uptake rates at low external Ci concentrations and achieving high rates of photosynthesis. There are multiple ways in which model parameters can be varied, within a plausible range, to match measured rates of photosynthesis and CO2 uptake. To increase CO2 uptake rates, CA activity can be increased, kinetic characteristics of the putative chloroplast pump can be enhanced to increase HCO3 (-) export, or the cytoplasmic pH can be raised. To increase the photosynthetic rate, the permeability of the pyrenoid to CO2 can be reduced or RubisCO content can be increased.

  16. Effect of urban parks on CO2 concentrations in Toluca, Mexico

    Science.gov (United States)

    Vieyra Gómez, J. A.; González Sosa, E.; Mastachi-Loza, C. A.; Cervantes, M.; Martínez Valdéz, H.

    2013-05-01

    Despite green areas are used for amusement, they have several benefits such as: microclimate regulation, groundwater recharge, noise abatement, oxygen production and CO2 capture. The last one has a notable importance, as CO2 is considered to be one of the most pollutant gases of the greenhouse effect. The city of Toluca, has a considerable urban growth. However, there are few studies aimed to assess the importance of the green areas in urban locations. About this, it is estimated than only 4m2/hab of vegetal coverage is found in big cities, which means a 50% deficit according to the international standards.The aim of this study was to assess the urban parks impact in Toluca, as regulators of CO2 means through measurements in autumn-winter seasonal period, 2012-2013.It was performed 20 measurements in 4 local parks (Urawa, Alameda, Municipal and Metropolitano), in order to evaluate the possible effect of urban parks on CO2 concentrations. Transects were made inside and outside the parks and the CO2 concentrations were registered by a portable quantifier (GMP343).The data analysis allowed the separation of the parks based on CO2 concentrations; however, it was perceived a decreasing of CO2 inside the parks (370ppm), between 10 and 40 ppm less than those areas with traffic and pedestrians (399 ppm).

  17. [Effects of doubled CO2 concentration on Erigeron breviscapus growth and its active constituent accumulation].

    Science.gov (United States)

    Li, Xiu-Hua; Su, Wen-Hua; Zhou, Hong; Zhang, Guang-Fei

    2009-08-01

    With medicinal plant Erigeron breviscapus as test material, its biomass and the contents and yields of scutellarin and caffeate were monitored under doubled (800 +/- 100) micromol x mol(-1) and natural (400 +/- 25) micromol x mol(-1) CO2 concentration. Comparing with those under natural CO2 concentration, the biomass of E. breviscapus under doubled CO2 concentration increased by 22%, the contents of scutellarin and caffeate increased by 23% and 26%, and the yields of these two constituents increased by 37.6% and 45.3%, respectively. Different organs had different responses in their biomass and active constituent contents to the elevated CO2 concentration. Under doubled CO2 concentration, the plant N content decreased by 47.2% and was negatively correlated with active constituent contents, being accorded well to the C/N balance hypothesis, and the biomass was positively correlated with the active constituent contents while no trade-off was observed between plant growth and secondary metabolism, suggesting that rational application of CO2 could improve the yield and quality of E. breviscapus.

  18. Dynamics of dimethylsulphoniopropionate and dimethylsulphide under different CO2 concentrations during a mesocosm experiment

    Directory of Open Access Journals (Sweden)

    C. LeQuéré

    2008-03-01

    Full Text Available The potential impact of seawater acidification on the concentrations of dimethylsulfide (DMS and dimethylsulfoniopropionate (DMSP, and the activity of the enzyme DMSP-lyase was investigated during a pelagic ecosystem CO2 enrichment experiment (PeECE III in spring 2005. Natural phytoplankton blooms were studied for 24 days under present, double and triple partial pressures of CO2 (pCO2; pH=8.3, 8.0, 7.8 in triplicate 25 m3 enclosures. The results indicate similar DMSP concentrations and DMSP-lyase activity (DLA patterns for all treatments. Hence, DMSP and DLA do not seem to have been affected by the CO2 treatment. In contrast, DMS concentrations showed small but statistically significant differences in the temporal development of the low versus the high CO2 treatments. The low pCO2 enclosures had higher DMS concentrations during the first 10 days, after which the levels decreased earlier and more rapidly than in the other treatments. Integrated over the whole study period, DMS concentrations were not significantly different from those of the double and triple pCO2 treatments. Pigment and flow-cytometric data indicate that phytoplanktonic populations were generally similar between the treatments, suggesting a certain resilience of the marine ecosystem under study to the induced pH changes, which is reflected in DMSP and DLA. However, there were significant differences in bacterial community structure and the abundance of one group of viruses infecting nanoeukaryotic algae. The amount of DMS accumulated per total DMSP or chlorophyll-a differed significantly between the present and future scenarios, suggesting that the pathways for DMS production or bacterial DMS consumption were affected by seawater pH. A comparison with previous work (PeECE II suggests that DMS concentrations do not respond consistently to pelagic ecosystem CO2 enrichment experiments.

  19. Impact of cuticle on calculations of the CO2 concentration inside leaves.

    Science.gov (United States)

    Boyer, John S

    2015-12-01

    Water vapor over-estimates the CO 2 entering leaves during photosynthesis because the cuticle and epidermis transmit more water vapor than CO 2 . Direct measurements of internal CO 2 concentrations may be preferred. The CO2 concentration inside leaves (c i) is typically calculated from the relationship between water vapor diffusing out while CO2 diffuses in. Diffusion through the cuticle/epidermis is usually not considered. This study was undertaken to determine how much the calculations would be affected by including cuticle properties. Previous studies indicate that measurable amounts of CO2 and water vapor move through the cuticle, although much less CO2 than water vapor. The present experiments were conducted with sunflower (Helianthus annuus L) leaves in a gas exchange apparatus designed to directly measure c i, while simultaneously calculating c i. Results showed that, in normal air, calculated c i were always higher than directly measured ones, especially when abscisic acid was fed to the leaves to close the stomata and cause gas exchange to be dominated by the cuticle. The effect was attributed mostly to the reliance on the gas phase for the calculations without taking cuticle properties into account. Because cuticle properties are usually unknown and vary with the turgor of the leaf, which can stretch the waxes, it is difficult to include cuticle properties in the calculation. It was concluded that direct measurement of c i may be preferable to the calculations.

  20. Effect of elevated CO2 concentration on photosynthetic characteristics of hyperaccumulator Sedum alfredii under cadmium stress.

    Science.gov (United States)

    Li, Tingqiang; Tao, Qi; Di, Zhenzhen; Lu, Fan; Yang, Xiaoe

    2015-07-01

    The combined effects of elevated CO2 and cadmium (Cd) on photosynthetic rate, chlorophyll fluorescence and Cd accumulation in hyperaccumulator Sedum alfredii Hance were investigated to predict plant growth under Cd stress with rising atmospheric CO2 concentration. Both pot and hydroponic experiments were conducted and the plants were grown under ambient (350 µL L(-1)) or elevated (800 µL L(-1)) CO2 . Elevated CO2 significantly (P < 0.05) increased Pn (105%-149%), Pnmax (38.8%-63.0%) and AQY (20.0%-34.8%) of S. alfredii in all the Cd treatments, but reduced chlorophyll concentration, dark respiration and photorespiration. After 10 days growth in medium with 50 µM Cd under elevated CO2 , PSII activities were significantly enhanced (P < 0.05) with Pm, Fv/Fm, Φ(II) and qP increased by 66.1%, 7.5%, 19.5% and 16.4%, respectively, as compared with ambient-grown plants. Total Cd uptake in shoot of S. alfredii grown under elevated CO2 was increased by 44.1%-48.5%, which was positively correlated with the increase in Pn. These results indicate that elevated CO2 promoted the growth of S. alfredii due to increased photosynthetic carbon uptake rate and photosynthetic light-use efficiency, and showed great potential to improve the phytoextraction of Cd by S. alfredii. © 2014 Institute of Botany, Chinese Academy of Sciences.

  1. [Effects of elevated CO2 concentration on the quality of agricultural products: a review].

    Science.gov (United States)

    Chai, Ru-shan; Niu, Yao-fang; Zhu, Li-qing; Wang, Huan; Zhang, Yong-song

    2011-10-01

    The increasing concentration of atmospheric CO2 and the nutritional quality of human diets are the two important issues we are facing. At present, the atmospheric CO2 concentration is about 380 micromol mol(-1), and to be reached 550 micromol mol(-1) by 2050. A great deal of researches indicated that the quality of agricultural products is not only determined by inherited genes, but also affected by the crop growth environmental conditions. This paper summarized the common methods adopted at home and abroad for studying the effects of CO2 enrichment on the quality of agricultural products, and reviewed the research advances in evaluating the effects of elevated CO2 on the quality of rice, wheat, soybean, and vegetables. Many experimental results showed that elevated CO2 concentration causes a decrease of protein content in the grains of staple food crops and an overall decreasing trend of trace elements contents in the crops, but improves the quality of vegetable products to some extent. Some issues and future directions regarding the effects of elevated CO2 concentration on the quality of agricultural products were also discussed, based on the present status of related researches.

  2. [Photosynthetic characteristics of Bothriochloa ischaemum under drought stress and elevated CO2 concentration].

    Science.gov (United States)

    Zhang, Chang-Sheng; Liu, Guo-Bin; Xue, Sha; Ji, Zhi-Qing; Zhang, Chao

    2012-11-01

    A pot experiment was conducted to study the variations of the photo-physiological characteristics of native bluestem (Bothriochloa ischaemum) in loess hilly-gully region under different soil moisture condition (80% and 40% field capacity) and different atmospheric CO2 concentration (375 micromol x m(-2) x s(-1) and 750 micromol x m(-2) x s(-1). The results showed that drought stress decreased the maximum photosynthetic rate (Pn max), apparent quantum efficiency (AQE), stomatal conductance (ga), transpiration rate (Tx), maximum photochemical efficiency (F/Fm), potential photochemical efficiency (Fv/Fo), and photosynthetic pigments contents, and increased the malondialdehyde (MDA) and proline (Pro) contents. Under sufficient moisture condition, elevated CO2 concentration didn't change the P n max and the, MDA and Pro contents significantly; under drought stress, elevated CO2 improved the maximal fluorescence (Fm), Fv/Fm, Fv/Fo, photosynthetic pigments contents, and AQE, and the Pn max under elevated CO2 was increased significantly by 23.3%, and the MDA and Pro contents were decreased significantly, as compared with those under ambient CO2 concentration. All the results suggested that elevated CO2 concentration had definite compensation effect on the photosynthetic reduction of B. ischaemum induced by drought stress, and alleviated the damage of drought stress on B. ischaemum.

  3. The impact of elevated CO2 concentrations on soil microbial community, soil organic matter storage and nutrient cycling at a natural CO2 vent in NW Bohemia

    Science.gov (United States)

    Nowak, Martin; Beulig, Felix; von Fischer, Joe; Muhr, Jan; Kuesel, Kirsten; Trumbore, Susan

    2014-05-01

    Natural CO2 vents or 'mofettes' are diffusive or advective exhalations of geogenic CO2 from soils. These structures occur at several places worldwide and in most cases they are linked to volcanic activity. Characteristic for mofette soils are high CO2 concentrations of up to more than 90% as well as a lack of oxygen, low pH values and reducing conditions. Mofette soils usually are considered to be sites of carbon accumulation, which is not only due to the absence of oxygen, but might also result from lower plant litter quality due to CO2 fertilization of CO2 influenced plants and reduced availability of N and P for the decomposer community. Furthermore, fermentation processes and the formation of reduced elements by anoxic decomposition might fuel chemo-lithoautotrophic or mixotrophic microbial CO2 uptake, a process which might have important ecological functions by closing internal element cycles, formation of trace gasses as well as by re-cycling and storing of carbon. Several studies of microbial community structure revealed a shift towards CO2 utilizing prokaryotes in moffete soils compared to a reference site. Here, we use combined stable and radiocarbon isotope data from mofette soils in NW Bohemia to quantify the contribution of geogenic CO2 to soil organic carbon formation within mofette soils, either resulting from plant litter or from microbial CO2 uptake. This is possible because the geogenic CO2 has a distinct isotopic signature (δ13C = -2 o Δ14C = -1000 ) that is very different from the isotopic signature of atmospheric CO2. First results show that mofette soils have a high Corg content (20 to 40 %) compared to a reference site (2 to 20 %) and soil organic matter is enriched in 13C as well as depleted in 14C. This indicates that geogenic CO2 is re-fixed and stored as SOM. In order to quantify microbial contribution to CO2 fixation and SOM storage, microbial CO2 uptake rates were determined by incubating mofette soils with 13CO2 labelled gas. The

  4. Elevated CO2 concentration affects vertical distribution of photosynthetic activity in Calamagrostis arundinacea (L.) Roth

    Czech Academy of Sciences Publication Activity Database

    Klem, Karel; Holub, Petr; Urban, Otmar

    2017-01-01

    Roč. 10, 1-2 (2017), s. 67-74 ISSN 1803-2451 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : chlorophyll * CO2 assimilation * elevated CO2 * concentration * transpiration * vertical gradient * water-use efficiency Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) https://beskydy.mendelu.cz/10/1/0067/

  5. Effect of intraperitoneal CO2 concentration on postoperative pain after laparoscopic cholecystectomy.

    Science.gov (United States)

    Chung, Ji Won; Kang, Kyu Sik; Park, Sang Hyun; Kim, Chun Sook; Chung, Jin Hun; Yoo, Sie Hyeon; Kim, Nan Seol; Seo, Yong Han; Jung, Ho Soon; Chun, Hea Rim; Gong, Hyung Youn; Jung, Hae Il; Bae, Sang Ho; Park, Su Yeon

    2017-10-01

    This study set out to identify the association between the intraperitoneal CO2 concentrations and postoperative pain by dividing the participants into a control group and 2 experimental groups receiving irrigation (1 L and 2 L), and directly measuring their intraperitoneal CO2 concentrations with a CO2 gas detector. A total of 101 patients, American Society of Anesthesiologists physical status classification I and II patients aged 18-65 years were enrolled in the study. Group 1 did not receive irrigation with normal saline, while groups 2 and 3 were administered irrigation with 1 L and 2 L of normal saline, respectively, after laparoscopic cholecystectomy. Intraperitoneal CO2 concentrations were measured with a CO2 gas detector through the port, and postoperative pain was assessed on a visual analogue scale at 6, 12, and 24 hours after surgery. The intraperitoneal CO2 concentrations were 1,016.0 ± 960.3 ppm in group 1, 524.5 ± 383.2 ppm in group 2, and 362.2 ± 293.6 ppm in group 3, showing significantly lower concentrations in groups 2 and 3. Postoperative pain was significantly lower in group 3 at 6 hours after surgery, and in groups 2 and 3 at 12 hours after the surgery. However, there was no significant difference between the 3 groups in postoperative pain 24 hours after the surgery. This study found a causal relationship between the amount of normal saline used for irrigation and the intraperitoneal CO2 concentrations in that irrigation with normal saline reduces pain on the day of the surgery.

  6. Sensitive indicators of Stipa bungeana response to precipitation under ambient and elevated CO2 concentration

    Science.gov (United States)

    Shi, Yaohui; Zhou, Guangsheng; Jiang, Yanling; Wang, Hui; Xu, Zhenzhu

    2017-09-01

    Precipitation is a primary environmental factor in the semiarid grasslands of northern China. With increased concentrations of atmospheric greenhouse gases, precipitation regimes will change, and high-impact weather events may be more common. Currently, many ecophysiological indicators are known to reflect drought conditions, but these indicators vary greatly among species, and few studies focus on the applicability of these drought indicators under high CO2 conditions. In this study, five precipitation levels (- 30%, - 15%, control, + 15%, and + 30%) were used to simulate the effects of precipitation change on 18 ecophysiological characteristics in Stipa bungeana, including leaf area, plant height, leaf nitrogen (N), and chlorophyll content, among others. Two levels of CO2 concentration (ambient, 390 ppm; 550 ppm) were used to simulate the effects of elevated CO2 on these drought indicators. Using gray relational analysis and phenotypic plasticity analysis, we found that total leaf area or leaf number (morphology), leaf water potential or leaf water content (physiology), and aboveground biomass better reflected the water status of S. bungeana under ambient and elevated CO2 than the 13 other analyzed variables. The sensitivity of drought indicators changed under the elevated CO2 condition. By quantifying the relationship between precipitation and the five most sensitive indicators, we found that the thresholds of precipitation decreased under elevated CO2 concentration. These results will be useful for objective monitoring and assessment of the occurrence and development of drought events in S. bungeana grasslands.

  7. The effect of atmospheric CO2 concentration on carbon isotope fractionation in C3 land plants

    Science.gov (United States)

    Schubert, Brian A.; Jahren, A. Hope

    2012-11-01

    Because atmospheric carbon dioxide is the ultimate source of all land-plant carbon, workers have suggested that pCO2 level may exert control over the amount of 13C incorporated into plant tissues. However, experiments growing plants under elevated pCO2 in both chamber and field settings, as well as meta-analyses of ecological and agricultural data, have yielded a wide range of estimates for the effect of pCO2 on the net isotopic discrimination (Δδ13Cp) between plant tissue (δ13Cp) and atmospheric CO2 (δ13CCO2). Because plant stomata respond sensitively to plant water status and simultaneously alter the concentration of pCO2 inside the plant (ci) relative to outside the plant (ca), any experiment that lacks environmental control over water availability across treatments could result in additional isotopic variation sufficient to mask or cancel the direct influence of pCO2 on Δδ13Cp. We present new data from plant growth chambers featuring enhanced dynamic stabilization of moisture availability and relative humidity, in addition to providing constant light, nutrient, δ13CCO2, and pCO2 level for up to four weeks of plant growth. Within these chambers, we grew a total of 191 C3 plants (128 Raphanus sativus plants and 63 Arabidopsis thaliana) across fifteen levels of pCO2 ranging from 370 to 4200 ppm. Three types of plant tissue were harvested and analyzed for carbon isotope value: above-ground tissues, below-ground tissues, and leaf-extracted nC31-alkanes. We observed strong hyperbolic correlations (R ⩾ 0.94) between the pCO2 level and Δδ13Cp for each type of plant tissue analyzed; furthermore the linear relationships previously suggested by experiments across small (10-350 ppm) changes in pCO2 (e.g., 300-310 ppm or 350-700 ppm) closely agree with the amount of fractionation per ppm increase in pCO2 calculated from our hyperbolic relationship. In this way, our work is consistent with, and provides a unifying relationship for, previous work on carbon isotopes

  8. Effect of CO2 concentration on mosquito collection rate using odor-baited suction traps.

    Science.gov (United States)

    McPhatter, Lee; Gerry, Alec C

    2017-06-01

    Carbon dioxide (CO2 ) has been used for decades to enhance capture of host-seeking mosquitoes when released in association with traps commonly used by mosquito and vector control agencies. However, there is little published work evaluating the effect of altering CO2 release rates relative to the number of mosquitoes captured in these traps. This study investigated how varying CO2 concentration altered the mosquito collection rate at a freshwater wetlands in southern California. Host-seeking mosquitoes were captured in CDC-style traps baited with one of six CO2 release rates ranging from 0-1,495 ml/min from gas cylinders. Species captured were Aedes vexans, Anopheles franciscanus, An. hermsi, Culex erythrothorax, and Cx. tarsalis. A biting midge, Culicoides sonorensis, was also captured. For all species, increasing CO2 release rates resulted in increasing numbers of individual females captured, with the relative magnitude of this increase associated to some extent with known feeding preferences of these species. We found that variation in CO2 release rate can significantly alter mosquito capture rates, potentially leading to imprecise estimates of vector activity if the relationship of CO2 release rate to mosquito capture rate is not considered. © 2017 The Society for Vector Ecology.

  9. Columnar and Upper Level CO2 Concentration as Retrieved from IMG/ADEOS Thermal Infrared Data

    Science.gov (United States)

    Imasu, R.; Ota, Y.

    2005-12-01

    Two types of retrieval method have been applied to retrieving CO2 columnar and upper level concentrations from the thermal infrared radiation spectra observed by a Fourier Transform Spectrometer (FTS) sensor, Interferometric Monitor for Greenhouse gases (IMG), aboard the ADvanced Earth Observing Satellite (ADEOS). In the first method, temperature profiles were assumed to be those from the re-analysis data of ECMWF, ERA 40, and CO2 concentration at 600hPa were retrieved with a minimum variance method from the spectrum data at 15 micron absorption band. On the other hand, the principle of the second method used for estimating columnar CO2 concentration was similar to that of the occultation method considering the ground surface as a strong radiation source. The spectral biases that were attributable to temperature and water vapor retrieval errors were reduced through a baseline correction procedure. For this analysis, spectrum data measured at a weak absorption band, a laser band, of CO2 located around 940 cm-1 were used. Although most of Jacobian components of this week absorption band have peaks in the troposphere, the contribution from the Non-LTE effects was briefly estimated. The retrieved results showed concentration contrast between the northern and the southern hemisphere and seasonal change of this feature for the data of 1997. These results were mostly consistent with ground based CO2 data of CMDL/NOA, but systematic biases of concentration existed in both types of retrieved results.

  10. Modeling atmospheric CO2 concentration profiles and fluxes above sloping terrain at a boreal site

    Directory of Open Access Journals (Sweden)

    T. Aalto

    2006-01-01

    Full Text Available CO2 fluxes and concentrations were simulated in the planetary boundary layer above subarctic hilly terrain using a three dimensional model. The model solves the transport equations in the local scale and includes a vegetation sub-model. A WMO/GAW background concentration measurement site and an ecosystem flux measurement site are located inside the modeled region at a hilltop and above a mixed boreal forest, respectively. According to model results, the concentration measurement at the hill site was representative for continental background. However, this was not the case for the whole model domain. Concentration at few meters above active vegetation represented mainly local variation. Local variation became inseparable from the regional signal at about 60-100 m above ground. Flow over hills changed profiles of environmental variables and height of inversion layer, however CO2 profiles were more affected by upwind land use than topography. The hill site was above boundary layer during night and inside boundary layer during daytime. The CO2 input from model lateral boundaries dominated in both cases. Daily variation in the CO2 assimilation rate was clearly seen in the CO2 profiles. Concentration difference between the hill site and the forest site was about 5ppm during afternoon according to both model and measurements. The average modeled flux to the whole model region was about 40% of measured and modeled local flux at the forest site.

  11. Enhanced electrocatalytic CO2 reduction via field-induced reagent concentration.

    Science.gov (United States)

    Liu, Min; Pang, Yuanjie; Zhang, Bo; De Luna, Phil; Voznyy, Oleksandr; Xu, Jixian; Zheng, Xueli; Dinh, Cao Thang; Fan, Fengjia; Cao, Changhong; de Arquer, F Pelayo García; Safaei, Tina Saberi; Mepham, Adam; Klinkova, Anna; Kumacheva, Eugenia; Filleter, Tobin; Sinton, David; Kelley, Shana O; Sargent, Edward H

    2016-09-15

    Electrochemical reduction of carbon dioxide (CO2) to carbon monoxide (CO) is the first step in the synthesis of more complex carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the reaction suffers from slow kinetics owing to the low local concentration of CO2 surrounding typical CO2 reduction reaction catalysts. Alkali metal cations are known to overcome this limitation through non-covalent interactions with adsorbed reagent species, but the effect is restricted by the solubility of relevant salts. Large applied electrode potentials can also enhance CO2 adsorption, but this comes at the cost of increased hydrogen (H2) evolution. Here we report that nanostructured electrodes produce, at low applied overpotentials, local high electric fields that concentrate electrolyte cations, which in turn leads to a high local concentration of CO2 close to the active CO2 reduction reaction surface. Simulations reveal tenfold higher electric fields associated with metallic nanometre-sized tips compared to quasi-planar electrode regions, and measurements using gold nanoneedles confirm a field-induced reagent concentration that enables the CO2 reduction reaction to proceed with a geometric current density for CO of 22 milliamperes per square centimetre at -0.35 volts (overpotential of 0.24 volts). This performance surpasses by an order of magnitude the performance of the best gold nanorods, nanoparticles and oxide-derived noble metal catalysts. Similarly designed palladium nanoneedle electrocatalysts produce formate with a Faradaic efficiency of more than 90 per cent and an unprecedented geometric current density for formate of 10 milliamperes per square centimetre at -0.2 volts, demonstrating the wider applicability of the field-induced reagent concentration concept.

  12. The effects of high soil CO2 concentrations on leaf reflectance of maize plants

    NARCIS (Netherlands)

    Noomen, M.F.; Skidmore, A.K.

    2009-01-01

    Carbon dioxide gas at higher concentrations is known to kill vegetation and can also lead to asphyxiation in humans and animals. The objective of this study is to test whether soil CO2 concentrations ranging from 2% to 50% can be detected using vegetative spectral reflectance. A greenhouse

  13. Mutate Chlorella sp. by nuclear irradiation to fix high concentrations of CO2.

    Science.gov (United States)

    Cheng, Jun; Huang, Yun; Feng, Jia; Sun, Jing; Zhou, Junhu; Cen, Kefa

    2013-05-01

    To improve biomass productivity and CO2 fixation of microalgae under 15% (v/v) CO2 of flue gas, Chlorella species were mutated by nuclear irradiation and domesticated with high concentrations of CO2. The biomass yield of Chlorella pyrenoidosa mutated using 500 Gy of (60)Co γ irradiation increased by 53.1% (to 1.12 g L(-1)) under air bubbling. The mutants were domesticated with gradually increased high concentrations of CO2 [from 0.038% (v/v) to 15% (v/v)], which increased the biomass yield to 2.41 g L(-1). When light transmission and culture mixing in photo-bioreactors were enhanced at 15% (v/v) CO2, the peak growth rate of the domesticated mutant (named Chlorella PY-ZU1) was increased to 0.68 g L(-1) d(-1). When the ratio of gas flow rate (L min(-1)) to 1L of microalgae culture was 0.011, the peak CO2 fixation rate and the efficiency of Chlorella PY-ZU1 were 1.54 g L(-1) d(-1) and 32.7%, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data

    Science.gov (United States)

    Ogle, Stephen M.; Davis, Kenneth; Lauvaux, Thomas; Schuh, Andrew; Cooley, Dan; West, Tristram O.; Heath, Linda S.; Miles, Natasha L.; Richardson, Scott; Breidt, F. Jay; Smith, James E.; McCarty, Jessica L.; Gurney, Kevin R.; Tans, Pieter; Denning, A. Scott

    2015-03-01

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country’s contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated emissions associated with managing lands for carbon sequestration and other activities, which often have large uncertainties. We report here on the challenges and results associated with a case study using atmospheric measurements of CO2 concentrations and inverse modeling to verify nationally-reported biogenic CO2 emissions. The biogenic CO2 emissions inventory was compiled for the Mid-Continent region of United States based on methods and data used by the US government for reporting to the UNFCCC, along with additional sources and sinks to produce a full carbon balance. The biogenic emissions inventory produced an estimated flux of -408 ± 136 Tg CO2 for the entire study region, which was not statistically different from the biogenic flux of -478 ± 146 Tg CO2 that was estimated using the atmospheric CO2 concentration data. At sub-regional scales, the spatial density of atmospheric observations did not appear sufficient to verify emissions in general. However, a difference between the inventory and inversion results was found in one isolated area of West-central Wisconsin. This part of the region is dominated by forestlands, suggesting that further investigation may be warranted into the forest C stock or harvested wood product data from this portion of the study area. The results suggest that observations of atmospheric CO2 concentration data and inverse modeling could be used to verify biogenic emissions, and provide more confidence in biogenic GHG emissions reporting to the UNFCCC.

  15. 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.

  16. Soil CO2 concentrations and efflux dynamics of a tree island in the Pantanal wetland

    Science.gov (United States)

    Lathuillière, Michael J.; Pinto, Osvaldo B.; Johnson, Mark S.; Jassal, Rachhpal S.; Dalmagro, Higo J.; Leite, Nei K.; Speratti, Alicia B.; Krampe, Daniela; Couto, Eduardo G.

    2017-08-01

    The Pantanal is the largest tropical wetland on the planet, and yet little information is available on the biome's carbon cycle. We used an automatic station to measure soil CO2 concentrations and oxidation-reduction potential over the 2014 and 2015 flood cycles of a tree island in the Pantanal that is immune to inundation during the wetland's annual flooding. The soil CO2 concentration profile was then used to estimate soil CO2 efflux over the two periods. In 2014, subsurface soil saturation at 0.30 m depth created conditions in that layer that led to CO2 buildup close to 200,000 ppm and soil oxidation-reduction potential below -300 mV, conditions that were not repeated in 2015 due to annual variability in soil saturation at the site. Mean CO2 efflux over the 2015 flood cycle was 0.023 ± 0.103 mg CO2-C m-2 s-1 representing a total annual efflux of 593 ± 2690 mg CO2-C m-2 y-1. Unlike a nearby tree island site that experiences full inundation during the wet season, here the soil dried quickly following repeated rain events throughout the year, which led to the release of CO2 pulses from the soil. This study highlights not only the complexity and heterogeneity in the Pantanal's carbon balance based on differences in topography, flood cycles, and vegetation but also the challenges of applying the gradient method in the Pantanal due to deviations from steady state conditions.

  17. 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.

  18. Soil air CO2 concentration as an integrative parameter of soil structure

    Science.gov (United States)

    Ebeling, Corinna; Gaertig, Thorsten; Fründ, Heinz-Christian

    2015-04-01

    The assessment of soil structure is an important but difficult issue and normally takes place in the laboratory. Typical parameters are soil bulk density, porosity, water or air conductivity or gas diffusivity. All methods are time-consuming. The integrative parameter soil air CO2 concentration ([CO2]) can be used to assess soil structure in situ and in a short time. Several studies highlighted that independent of soil respiration, [CO2] in the soil air increases with decreasing soil aeration. Therefore, [CO2] is a useful indicator of soil aeration. Embedded in the German research project RÜWOLA, which focus on soil protection at forest sites, we investigated soil compaction and recovery of soil structure after harvesting. Therefore, we measured soil air CO2 concentrations continuously and in single measurements and compared the results with the measurements of bulk density, porosity and gas diffusivity. Two test areas were investigated: At test area 1 with high natural regeneration potential (clay content approx. 25 % and soil-pH between 5 and 7), solid-state CO2-sensors using NDIR technology were installed in the wheel track of different aged skidding tracks in 5 and 10 cm soil depths. At area 2 (acidic silty loam, soil-pH between 3.5 and 4), CO2-sensors and water-tension sensors (WatermarkR) were installed in 6 cm soil depth. The results show a low variance of [CO2] in the undisturbed soil with a long term mean from May to June 2014 between 0.2 and 0.5 % [CO2] in both areas. In the wheel tracks [CO2] was consistently higher. The long term mean [CO2] in the 8-year-old-wheel track in test area 1 is 5 times higher than in the reference soil and shows a high variation (mean=2.0 %). The 18-year-old wheel track shows a long-term mean of 1.2 % [CO2]. Furthermore, there were strong fluctuations of [CO2] in the wheel tracks corresponding to precipitation and humidity. Similar results were yielded with single measurements during the vegetation period using a portable

  19. Atmospheric CO2 concentrations during ancient greenhouse climates were similar to those predicted for A.D. 2100.

    Science.gov (United States)

    Breecker, D O; Sharp, Z D; McFadden, L D

    2010-01-12

    Quantifying atmospheric CO(2) concentrations ([CO(2)](atm)) during Earth's ancient greenhouse episodes is essential for accurately predicting the response of future climate to elevated CO(2) levels. Empirical estimates of [CO(2)](atm) during Paleozoic and Mesozoic greenhouse climates are based primarily on the carbon isotope composition of calcium carbonate in fossil soils. We report that greenhouse [CO(2)](atm) have been significantly overestimated because previously assumed soil CO(2) concentrations during carbonate formation are too high. More accurate [CO(2)](atm), resulting from better constraints on soil CO(2), indicate that large (1,000s of ppmV) fluctuations in [CO(2)](atm) did not characterize ancient climates and that past greenhouse climates were accompanied by concentrations similar to those projected for A.D. 2100.

  20. Impacts of climate change and CO2 concentration on wheat yield in Iran and adaptation strategies

    Directory of Open Access Journals (Sweden)

    alireza koochaki

    2009-06-01

    Full Text Available The Impact of climate change on irrigated wheat yield in Iran was studied using a simulation model under different climatic scenarios. SUCROS-wheat model which was adapted for the effect of CO2 concentration on photosynthetic parameters, were calibrated and validated against observed wheat yield obtained from different regions of country. Interaction effect of CO2 concentration and temperature on wheat yield was simulated at 3 CO2 concentrations including 350 (current, 550 and 700ppm (doubled in combination with increasing mean daily temperature by 0 (unchanged, 1, 2, 3 and 4°C. In addition climatic conditions of the year 2050 were predicted by using GISS and GFDL General Circulation Models (GCM based on IPCC scenarios for the target year. The GCMs were first calibrated by the long term (40 years weather data from 25 stations located in different wheat production regions across the country. Predicted weather data of GCMs were used as the inputs of simulation model after statistical downscaling and generating daily weather parameters. Wheat yield at different regions was estimated for the climatic conditions of the target year with and without increased CO2 concentration. Finally adaptation strategies for improving wheat yield under future climate were evaluated by means of simulation model. The results showed that despite of some deviation between the two GCMs, average temperature will be changed in the range of 3.5-4.4°C with an increasing gradient from West to East and North to South of the country. This warming pattern will be led to the higher frequency of temperatures above 30°C during the flowering stage of wheat in the most regions. Increasing CO2 concentration without warming showed positive effects on wheat yield. However, the effect of CO2 was compensated for by temperature. Based on simulation results wheat yield was reduced when mean temperature was raised above 3°C even at doubling CO2 concentration. Predicted wheat yield for

  1. Rising atmospheric CO2 concentration may imply higher risk of Fusarium mycotoxin contamination of wheat grains.

    Science.gov (United States)

    Bencze, Szilvia; Puskás, Katalin; Vida, Gyula; Karsai, Ildikó; Balla, Krisztina; Komáromi, Judit; Veisz, Ottó

    2017-08-01

    Increasing atmospheric CO2 concentration not only has a direct impact on plants but also affects plant-pathogen interactions. Due to economic and health-related problems, special concern was given thus in the present work to the effect of elevated CO2 (750 μmol mol(-1)) level on the Fusarium culmorum infection and mycotoxin contamination of wheat. Despite the fact that disease severity was found to be not or little affected by elevated CO2 in most varieties, as the spread of Fusarium increased only in one variety, spike grain number and/or grain weight decreased significantly at elevated CO2 in all the varieties, indicating that Fusarium infection generally had a more dramatic impact on the grain yield at elevated CO2 than at the ambient level. Likewise, grain deoxynivalenol (DON) content was usually considerably higher at elevated CO2 than at the ambient level in the single-floret inoculation treatment, suggesting that the toxin content is not in direct relation to the level of Fusarium infection. In the whole-spike inoculation, DON production did not change, decreased or increased depending on the variety × experiment interaction. Cooler (18 °C) conditions delayed rachis penetration while 20 °C maximum temperature caused striking increases in the mycotoxin contents, resulting in extremely high DON values and also in a dramatic triggering of the grain zearalenone contamination at elevated CO2. The results indicate that future environmental conditions, such as rising CO2 levels, may increase the threat of grain mycotoxin contamination.

  2. Revealing Transient Concentration of CO2 in a Mixed Matrix Membrane by IR Microimaging and Molecular Modeling

    KAUST Repository

    Hwang, Seungtaik

    2018-02-21

    Through IR microimaging the spatially and temporally resolved development of the CO2 concentration in a ZIF-8@6FDA-DAM mixed matrix membrane was visualized during transient adsorption. By recording the evolution of the CO2 concentration, it is observed that the CO2 molecules propagate from the ZIF-8 filler, which acts as a transport

  3. Atmospheric CO2 concentration effects on rice water use and biomass production.

    Science.gov (United States)

    Kumar, Uttam; Quick, William Paul; Barrios, Marilou; Sta Cruz, Pompe C; Dingkuhn, Michael

    2017-01-01

    Numerous studies have addressed effects of rising atmospheric CO2 concentration on rice biomass production and yield but effects on crop water use are less well understood. Irrigated rice evapotranspiration (ET) is composed of floodwater evaporation and canopy transpiration. Crop coefficient Kc (ET over potential ET, or ETo) is crop specific according to FAO, but may decrease as CO2 concentration rises. A sunlit growth chamber experiment was conducted in the Philippines, exposing 1.44-m2 canopies of IR72 rice to four constant CO2 levels (195, 390, 780 and 1560 ppmv). Crop geometry and management emulated field conditions. In two wet (WS) and two dry (DS) seasons, final aboveground dry weight (agdw) was measured. At 390 ppmv [CO2] (current ambient level), agdw averaged 1744 g m-2, similar to field although solar radiation was only 61% of ambient. Reduction to 195 ppmv [CO2] reduced agdw to 56±5% (SE), increase to 780 ppmv increased agdw to 128±8%, and 1560 ppmv increased agdw to 142±5%. In 2013WS, crop ET was measured by weighing the water extracted daily from the chambers by the air conditioners controlling air humidity. Chamber ETo was calculated according to FAO and empirically corrected via observed pan evaporation in chamber vs. field. For 390 ppmv [CO2], Kc was about 1 during crop establishment but increased to about 3 at flowering. 195 ppmv CO2 reduced Kc, 780 ppmv increased it, but at 1560 ppmv it declined. Whole-season crop water use was 564 mm (195 ppmv), 719 mm (390 ppmv), 928 mm (780 ppmv) and 803 mm (1560 ppmv). With increasing [CO2], crop water use efficiency (WUE) gradually increased from 1.59 g kg-1 (195 ppmv) to 2.88 g kg-1 (1560 ppmv). Transpiration efficiency (TE) measured on flag leaves responded more strongly to [CO2] than WUE. Responses of some morphological traits are also reported. In conclusion, increased CO2 promotes biomass more than water use of irrigated rice, causing increased WUE, but it does not help saving water. Comparability

  4. Atmospheric CO2 concentration effects on rice water use and biomass production.

    Directory of Open Access Journals (Sweden)

    Uttam Kumar

    Full Text Available Numerous studies have addressed effects of rising atmospheric CO2 concentration on rice biomass production and yield but effects on crop water use are less well understood. Irrigated rice evapotranspiration (ET is composed of floodwater evaporation and canopy transpiration. Crop coefficient Kc (ET over potential ET, or ETo is crop specific according to FAO, but may decrease as CO2 concentration rises. A sunlit growth chamber experiment was conducted in the Philippines, exposing 1.44-m2 canopies of IR72 rice to four constant CO2 levels (195, 390, 780 and 1560 ppmv. Crop geometry and management emulated field conditions. In two wet (WS and two dry (DS seasons, final aboveground dry weight (agdw was measured. At 390 ppmv [CO2] (current ambient level, agdw averaged 1744 g m-2, similar to field although solar radiation was only 61% of ambient. Reduction to 195 ppmv [CO2] reduced agdw to 56±5% (SE, increase to 780 ppmv increased agdw to 128±8%, and 1560 ppmv increased agdw to 142±5%. In 2013WS, crop ET was measured by weighing the water extracted daily from the chambers by the air conditioners controlling air humidity. Chamber ETo was calculated according to FAO and empirically corrected via observed pan evaporation in chamber vs. field. For 390 ppmv [CO2], Kc was about 1 during crop establishment but increased to about 3 at flowering. 195 ppmv CO2 reduced Kc, 780 ppmv increased it, but at 1560 ppmv it declined. Whole-season crop water use was 564 mm (195 ppmv, 719 mm (390 ppmv, 928 mm (780 ppmv and 803 mm (1560 ppmv. With increasing [CO2], crop water use efficiency (WUE gradually increased from 1.59 g kg-1 (195 ppmv to 2.88 g kg-1 (1560 ppmv. Transpiration efficiency (TE measured on flag leaves responded more strongly to [CO2] than WUE. Responses of some morphological traits are also reported. In conclusion, increased CO2 promotes biomass more than water use of irrigated rice, causing increased WUE, but it does not help saving water. Comparability

  5. Seasonally varying contributions to urban CO2 in the Chicago, Illinois, USA region: Insights from a high-resolution CO2 concentration and δ13C record

    Directory of Open Access Journals (Sweden)

    Joel Moore

    2015-06-01

    Full Text Available Abstract Understanding urban carbon cycling is essential given that cities sustain 54% of the global population and contribute 70% of anthropogenic CO2 emissions. When combined with CO2 concentration measurements ([CO2], stable carbon isotope analyses (δ13C can differentiate sources of CO2, including ecosystem respiration and combustion of fossil fuels, such as petroleum and natural gas. In this study, we used a wavelength scanned-cavity ringdown spectrometer to collect ∼2x106 paired measurements for [CO2] and δ13C values in Evanston, IL for August 2011 through February 2012. Evanston is located immediately north of Chicago, IL, the third largest city in the United States. The measurements represent one of the longest records of urban [CO2] and δ13C values thus far reported. We also compiled local meteorological information, as well as complementary [CO2] and δ13C data for background sites in Park Falls, WI and Mauna Loa, HI. We use the dataset to examine how ecosystem processes, fossil fuel usage, wind speed, and wind direction control local atmospheric [CO2] and δ13C in a midcontinent urban setting on a seasonal to daily basis. On average, [CO2] and δ13C values in Evanston were 16–23 ppm higher and 0.97–1.13‰ lower than the background sites. While seasonal [CO2] and δ13C values generally followed broader northern hemisphere trends, the difference between Evanston and the background sites was larger in winter versus summer. Mixing calculations suggest that ecosystem respiration and petroleum combustion equally contributed CO2 in excess of background during the summer and that natural gas combustion contributed 80%–94% of the excess CO2 in winter. Wind speed and direction strongly influenced [CO2] and δ13C values on an hourly time scale. The highest [CO2] and lowest δ13C values occurred at wind speeds <3 m s−1 and when winds blew from the northwest, west, and south over densely populated neighborhoods.

  6. A possible CO2 conducting and concentrating mechanism in plant stomata SLAC1 channel.

    Directory of Open Access Journals (Sweden)

    Qi-Shi Du

    Full Text Available BACKGROUND: The plant SLAC1 is a slow anion channel in the membrane of stomatal guard cells, which controls the turgor pressure in the aperture-defining guard cells, thereby regulating the exchange of water vapour and photosynthetic gases in response to environmental signals such as drought, high levels of carbon dioxide, and bacterial invasion. Recent study demonstrated that bicarbonate is a small-molecule activator of SLAC1. Higher CO(2 and HCO(3(- concentration activates S-type anion channel currents in wild-type Arabidopsis guard cells. Based on the SLAC1 structure a theoretical model is derived to illustrate the activation of bicarbonate to SLAC1 channel. Meanwhile a possible CO(2 conducting and concentrating mechanism of the SLAC1 is proposed. METHODOLOGY: The homology structure of Arabidopsis thaliana SLAC1 (AtSLAC1 provides the structural basis for study of the conducting and concentrating mechanism of carbon dioxide in SLAC1 channels. The pK(a values of ionizable amino acid side chains in AtSLAC1 are calculated using software PROPKA3.0, and the concentration of CO(2 and anion HCO(3(- are computed based on the chemical equilibrium theory. CONCLUSIONS: The AtSLAC1 is modeled as a five-region channel with different pH values. The top and bottom layers of channel are the alkaline residue-dominated regions, and in the middle of channel there is the acidic region surrounding acidic residues His332. The CO(2 concentration is enhanced around 10(4 times by the pH difference between these regions, and CO(2 is stored in the hydrophobic region, which is a CO(2 pool. The pH driven CO(2 conduction from outside to inside balances the back electromotive force and maintain the influx of anions (e.g. Cl(- and NO(3(- from inside to outside. SLAC1 may be a pathway providing CO(2 for photosynthesis in the guard cells.

  7. INTERSPECIFIC VARIATION IN THE GROWTH-RESPONSE OF PLANTS TO AN ELEVATED AMBIENT CO2 CONCENTRATION

    NARCIS (Netherlands)

    POORTER, H

    The effect of a doubling in the atmospheric CO2 concentration on the growth of vegetative whole plants was investigated. In a compilation of literature sources, the growth stimulation of 156 plant species was found to be on average 37%. This enhancement is small compared to what could be expected on

  8. Simulation of CO2 concentrations at Tsukuba tall tower using WRF ...

    Indian Academy of Sciences (India)

    They could explain the monthly concentration variation at the tower sites on the basis of the influence of different biomes like corn, soy, grass and other forest vegetation over the region. The monthly averaged gradients in CO2 over the central USA region were tied to regional patterns in net ecosystem exchange. Ballav et al.

  9. Modelling the response of wheat canopy assimilation to atmospheric CO2 concentrations.

    NARCIS (Netherlands)

    Rodriguez, D.; Ewert, F.; Goudriaan, J.; Manderscheid, R.; Burkart, S.; Weigel, H.J.

    2001-01-01

    The predictive capacity of two simulation models with different degrees of complexity for the calculation of assimilate production, was tested at different time scales, using a data set of wheat grown in an open-top-chamber experiment at two CO2 concentrations. Observed values of net canopy

  10. Effects of Temperature Rise and Increase in CO2 Concentration on Simulated Wheat Yields in Europe

    NARCIS (Netherlands)

    Nonhebel, Sanderine

    1996-01-01

    A crop-growth-simulation model based on SUCROS87 was used to study effects of temperature rise and increase of atmospheric CO2 concentration on wheat yields in several regions in Europe. The model simulated potential and water-limited crop production (growth with ample supply of nutrients and in the

  11. Future atmospheric CO2 concentration and environmental consequences for the feed market: a consequential LCA

    DEFF Research Database (Denmark)

    Saxe, Henrik; Hamelin, Lorie; Hinrichsen, Torben

    2014-01-01

    With the rising atmospheric carbon dioxide concentration [CO2], crops will assimilate more carbon. This will increase yields in terms of carbohydrates but dilute the content of protein and minerals in crops. This consequential life cycle assessment study modelled the environmental consequences...

  12. Rising atmospheric CO2 lowers food zinc, iron, and protein concentrations

    Science.gov (United States)

    Dietary deficiencies of zinc and iron are a major global public health problem. Most people who experience these deficiencies depend on agricultural crops for zinc and iron. In this context, the influence of rising concentrations of atmospheric CO2 on the availability of these nutrients from crops i...

  13. [Effects of elevated CO2 concentration on physiological characters of three dwarf ornamental bamboo species].

    Science.gov (United States)

    Zhuang, Ming-Hao; Chen, Shuang-Lin; Li, Ying-Chun; Guo, Zi-Wu; Yang, Qing-Ping

    2013-09-01

    By using open-top chambers (OTCs) to simulate the scenes of elevated CO2 concentrations [500 micromol x mol(-1) (T1) and 700 micromol x mol(-1) (T2)], and taking ambient atmospheric CO2 concentration as the control (CK), this paper studied the effects of elevated CO2 concentration on the lipid peroxidation and anti-oxidation enzyme system in Indocalamus decorus, Pleioblastus kongosanensis, and Sasa glabra leaves. After 103 days treatment, the O2(-)* and MDA contents, relative electron conduction, and soluble sugar content in the three dwarf ornamental bamboo species leaves in T1 had no obvious change, but the activities of anti-oxidation enzymes (SOD, POD, CAT, and APX) changed to a certain extent. In T2, the MDA content and relative electron conduction had no obvious change, but the O2(-)* and soluble sugar contents and the anti-oxidation enzymes activities changed obviously. The adaptation capacity of the three bamboo species to elevated CO2 concentration was in the order of I. decorus > P. kongosanensis > S. glabra.

  14. A statistical analysis of three ensembles of crop model responses to temperature and CO2 concentration

    Science.gov (United States)

    Ensembles of process-based crop models are now commonly used to simulate crop growth and development for climate scenarios of temperature and/or precipitation changes corresponding to different projections of atmospheric CO2 concentrations. This approach generates large datasets with thousands of de...

  15. Vegetative biomass predicts inflorescence production along a CO2 concentration gradient in mesic grassland

    Science.gov (United States)

    Atmospheric CO2 concentration will likely exceed 500 uL L-1 by 2050, often increasing plant community productivity in part by increasing abundance of species favored by increased CA. Whether increased abundance translates to increased inflorescence production is poorly understood, and is important ...

  16. CO2 concentration and occupancy density in the critical zones served by the VAV system

    Science.gov (United States)

    Etoua Evina, Ghislaine; Kajl, Stanislaw; Lamarche, Louis; Beltran-Galindo, Javier

    2017-11-01

    This article presents the results obtained from monitoring a VAV system with highly diversified zone occupancy density are presented in the article. The investigated VAV system meets the load for 72 zones (68 perimeters and 4 interiors) consisting of classrooms, offices, conference rooms, etc. with highly diversified occupancy densities from 1.875 to 2.5 m2/person for the classrooms and from 10 to 15 m2/person for the offices. The monitoring shows that the CO2 concentration can exceed the set point in the critical rooms. Simulation results are also presented in the article to show that it is often impossible to adjust the operation of such VAV systems because the adjusted System Outdoor Air Fractions, % OA, can reach 100% even where the zone CO2 concentration is not respected. The presented monitoring and simulation results were obtained in the winter, with the VAV system operating at partial load and with the minimum outdoor air flowrate required by the economizer system. As shown in the article, to respect the zone set point CO2 concentration in such period, the VAV system must operate mostly at a %OA equal to 100% instead of its minimum value. To circumvent this, the supply zone air flow rate may have to be designed taking into account the CO2 concentration resulting from the critical zones occupancy density.

  17. Diel Variation in Gene Expression of the CO2-Concentrating Mechanism during a Harmful Cyanobacterial Bloom

    NARCIS (Netherlands)

    Sandrini, Giovanni; Tann, Robert P.; Schuurmans, J. Merijn; van Beusekom, Sebastiaan A. M.; Matthijs, Hans C. P.; Huisman, Jef

    2016-01-01

    Dense phytoplankton blooms in eutrophic waters often experience large daily fluctuations in environmental conditions. We investigated how this diel variation affects in situ gene expression of the CO2-concentrating mechanism (CCM) and other selected genes of the harmful cyanobacterium Microcystis

  18. Exchange of carbonyl sulfide (OCS) between soils and atmosphere under various CO2 concentrations

    Science.gov (United States)

    Bunk, Rüdiger; Behrendt, Thomas; Yi, Zhigang; Andreae, Meinrat O.; Kesselmeier, Jürgen

    2017-06-01

    A new continuous integrated cavity output spectroscopy analyzer and an automated soil chamber system were used to investigate the exchange processes of carbonyl sulfide (OCS) between soils and the atmosphere under laboratory conditions. The exchange patterns of OCS between soils and the atmosphere were found to be highly dependent on soil moisture and ambient CO2 concentration. With increasing soil moisture, OCS exchange ranged from emission under dry conditions to an uptake within an optimum moisture range, followed again by emission at high soil moisture. Elevated CO2 was found to have a significant impact on the exchange rate and direction as tested with several soils. There is a clear tendency toward a release of OCS at higher CO2 levels (up to 7600 ppm), which are typical for the upper few centimeters within soils. At high soil moisture, the release of OCS increased sharply. Measurements after chloroform vapor application show that there is a biotic component to the observed OCS exchange. Furthermore, soil treatment with the fungi inhibitor nystatin showed that fungi might be the dominant OCS consumers in the soils we examined. We discuss the influence of soil moisture and elevated CO2 on the OCS exchange as a change in the activity of microbial communities. Physical factors such as diffusivity that are governed by soil moisture also play a role. Comparing KM values of the enzymes to projected soil water CO2 concentrations showed that competitive inhibition is unlikely for carbonic anhydrase and PEPCO but might occur for RubisCO at higher CO2 concentrations.

  19. Meteorological factors controlling soil gases and indoor CO2 concentration: a permanent risk in degassing areas.

    Science.gov (United States)

    Viveiros, Fátima; Ferreira, Teresa; Silva, Catarina; Gaspar, João L

    2009-02-01

    Furnas volcano is one of the three quiescent central volcanoes of São Miguel Island (Azores Archipelago, Portugal). Its present activity is marked by several degassing manifestations, including fumarolic fields, thermal and cold CO2 springs and soil diffuse degassing areas. One of the most important soil diffuse degassing areas extends below Furnas village, located inside the volcano caldera. A continuous gas geochemistry programme was started at Furnas volcano in October 2001 with the installation of a permanent soil CO2 efflux station that has coupled meteorological sensors to measure barometric pressure, rain, air and soil temperature, air humidity, soil water content and wind speed and direction. Spike-like oscillations are observed on the soil CO2 efflux time series and are correlated with low barometric pressure and heavy rainfall periods. Stepwise multiple regression analysis, applied to the time series obtained, verified that the meteorological variables explain 43.3% of the gas efflux variations. To assess the impact of these influences in inhabited zones a monitoring test was conducted in a Furnas village dwelling placed where soil CO2 concentration is higher than 25 vol.%. Indoor CO2 air concentration measurements at the floor level reached values as higher as 20.8 vol.% during stormy weather periods. A similar test was performed in another degassing area, Mosteiros village, located on the flank of Sete Cidades volcano (S. Miguel Island), showing the same kind of relation between indoor CO2 concentrations and barometric pressure. This work shows that meteorological conditions alone increase the gas exposure risk for populations living in degassing areas.

  20. Emissions of volatile organic compounds from hybrid poplar depend on CO2 concentration and genotype

    Science.gov (United States)

    Eller, A. S.; de Gouw, J. A.; Monson, R. K.

    2010-12-01

    Hybrid poplar is a fast-growing tree species that is likely to be an important source of biomass for the production of cellulose-based biofuels and may influence regional atmospheric chemistry through the emission of volatile organic compounds (VOCs). We used proton-transfer reaction mass spectrometry to measure VOC emissions from the leaves of four different hybrid poplar genotypes grown under ambient (400 ppm) and elevated (650 ppm) carbon dioxide concentration (CO2). The purpose of this experiment was to determine whether VOC emissions are different among genotypes and whether these emissions are likely to change as atmospheric CO2 rises. Methanol and isoprene made up over 90% of the VOC emissions and were strongly dependent on leaf age, with young leaves producing primarily methanol and switching to isoprene production as they matured. Monoterpene emissions were small, but tended to be higher in young leaves. Plants grown under elevated CO2 emitted smaller quantities of both methanol and isoprene, but the magnitude of the effect was dependent on genotype. Isoprene emission rates from mature leaves dropped from ~35 to ~28 nmol m-2 s-1 when plants were grown under elevated CO2. Emissions from individuals grown under ambient CO2 varied more based on genotype than those grown under elevated CO2, which means that we might expect smaller differences between genotypes in the future. Genotype and CO2 also affected how much carbon (C) individuals allocated to the production of VOCs. The emission rate of C from VOCs was 0.5 - 2% of the rate at which C was assimilated via net photosynthesis. The % C emitted was strongly related to genotype; clones from crosses between Populus deltoides and P. trichocarpa (T x D) allocated a greater % of their C to VOC emissions than clones from crosses of P. deltoids and P. nigra (D x N). Individuals from all four genotypes allocated a smaller % of their C to the emission of VOCs when they were grown under elevated CO2. These results

  1. Chemical effects of a high CO2 concentration in oxy-fuel combustion of methane

    DEFF Research Database (Denmark)

    Glarborg, Peter; Bentzen, L.L.B.

    2008-01-01

    in terms of a detailed chemical kinetic mechanism for hydrocarbon oxidation. On the basis of results of the present study, it can be expected that oxy-fuel combustion will lead to strongly increased CO concentrations in the near-burner region. The CO2 present will compete with O-2 for atomic hydrogen...... CO2. The high local CO levels may have implications for near-burner corrosion and stagging, but increased problems with CO emission in oxy-fuel combustion are not anticipated....

  2. Elevated temperature and CO(2) concentration effects on xylem anatomy of Scots pine.

    Science.gov (United States)

    Kilpeläinen, Antti; Gerendiain, Ane Zubizarreta; Luostarinen, Katri; Peltola, Heli; Kellomäki, Seppo

    2007-09-01

    We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment. The climate scenario included a doubling of [CO(2)] and a corresponding increase of 2-6 degrees C in temperature at the site depending on the season. Anatomical characteristics analyzed were annual earlywood, latewood and ring widths, intra-ring wood densities (earlywood, latewood and mean wood density), tracheid width, length, wall thickness, lumen diameter, wall thickness:lumen diameter ratio and mass per unit length (coarseness), and numbers of rays, resin canals and tracheids per xylem cross-sectional area. Elevated [CO(2)] increased ring width in four of six treatment years; earlywood width increased in the first two years and latewood width in the third year. Tracheid walls in both the earlywood and latewood tended to become thicker over the 6-year treatment period when temperature or [CO(2)] was elevated alone, whereas in the combined treatment they tended to become thinner relative to the tracheids of trees grown under ambient conditions. Latewood tracheid lumen diameters were larger in all the treatments relative to ambient conditions over the 6-year period, whereas lumen diameters in earlywood increased only in response to elevated [CO(2)] and were 3-6% smaller in the treatments with elevated temperature than in ambient conditions. Tracheid width, length and coarseness were greater in trees grown in elevated than in ambient temperature. The number of resin canals per mm(2) decreased in the elevated [CO(2)] treatment and increased in the elevated temperature treatments relative to ambient conditions. The treatments decreased the number of rays and tracheids per mm(2) of cross

  3. Study on effect of temperature and humidity on the CO2 concentration measurement

    Science.gov (United States)

    Liu, YuLiang; Ni, Xiang; Wu, YuanXi; Zhang, Wei

    2017-08-01

    In the application of non dispersive infrared (NDIR) carbon dioxide (CO2) concentration measurement, we need avoid the interference factors (such as temperature, pressure, gas, fluctuation of the light source and dust pollution etc.). In the past experiments only single factor, such as temperature, is often emphasized to the influence on the measurement results, without considering the effect of multiple factors. In order to study the change of gas concentration with measurement parameters, we constructs a CO2 detecting device with a BM530 gas detecting module, TMD10 temperature and humidity sensor. The experimental results show that: there is a correlation between the two interference factors: temperature and humidity. With the decreasing temperature, gas concentration measurement value decreases too. In developing process of instruments, we can make correction of the concentration- temperature instead of that of the measurement results under different temperature and humidity conditions.

  4. Can seasonal and interannual variation in landscape CO2 fluxes be detected by atmospheric observations of CO2 concentrations made at a tall tower?

    Science.gov (United States)

    Smallman, T. L.; Williams, M.; Moncrieff, J. B.

    2013-08-01

    The Weather Research and Forecasting (WRF) meteorological model has been coupled to the Soil Plant Atmosphere (SPA) terrestrial ecosystem model, hereafter known as WRF-SPA. SPA generates realistic land-atmosphere exchanges through fully coupled hydrological, carbon and energy cycles. Here we have used WRF-SPA to investigate regional scale observations of atmospheric CO2 concentrations made over a multi-annual period from a tall tower in Scotland. WRF-SPA realistically models both seasonal and daily cycles, predicting CO2 at the tall tower (R2 = 0.67, RMSE = 3.5 ppm, bias = 0.58 ppm), indicating realistic transport, and appropriate source sink distribution and magnitude of CO2 exchange. We have highlighted a consistent post harvest increase in model-observation residuals in atmospheric CO2 concentrations. This increase in model-observation residuals post harvest is likely related to a lack of an appropriate representation of uncultivated components (~ 36% of agricultural holding in Scotland) of agricultural land (e.g., hedgerows and forest patches) which continue to photosynthesise after the crop has been harvested. Through the use of ecosystem specific CO2 tracers we have shown that tall tower observations here do not detect a representative fraction of Scotland's ecosystem CO2 uptake. Cropland CO2 uptake is the dominant ecosystem signal detected at the tall tower, consistent with the dominance of cropland in the area surrounding the tower. However cropland is over-represented in the atmospheric CO2 concentrations simulated to be at the tall tower, relative to the simulated surface cropland CO2 uptake. Observations made at the tall tower were able to detect seasonal variation in ecosystem CO2 uptake, however a majority of variation was only detected for croplands. We have found evidence that interannual variation in weather has a greater impact than interannual variation of the simulated land surface CO2 exchange on tall tower observations for the simulated years

  5. Phytochemical changes in leaves of subtropical grasses and fynbos shrubs at elevated atmospheric CO 2 concentrations

    Science.gov (United States)

    Hattas, D.; Stock, W. D.; Mabusela, W. T.; Green, I. R.

    2005-07-01

    The effects of elevated atmospheric CO 2 concentrations on plant polyphenolic, tannin, nitrogen, phosphorus and total nonstructural carbohydrate concentrations were investigated in leaves of subtropical grass and fynbos shrub species. The hypothesis tested was that carbon-based secondary compounds would increase when carbon gain is in excess of growth requirements. This premise was tested in two ecosystems involving plants with different photosynthetic mechanisms and growth strategies. The first ecosystem comprised grasses from a C 4-dominated, subtropical grassland, where three plots were subjected to three different free air CO 2 enrichment treatments, i.e., elevated (600 to 800 μmol mol -1), intermediate (400 μmol mol -1) and ambient atmospheric CO 2. One of the seven grass species, Alloteropsis semialata, had a C 3 photosynthetic pathway while the other grasses were all C 4. The second ecosystem was simulated in a microcosm experiment where three fynbos species were grown in open-top chambers at ambient and 700 μmol mol -1 atmospheric CO 2 in low nutrient acid sands typical of south western coastal and mountain fynbos ecosystems. Results showed that polyphenolics and tannins did not increase in the grass species under elevated CO 2 and only in Leucadendron laureolum among the fynbos species. Similarly, foliar nitrogen content of grasses was largely unaffected by elevated CO 2, and among the fynbos species, only L. laureolum and Leucadendron xanthoconus showed changes in foliar nitrogen content under elevated CO 2, but these were of different magnitude. The overall decrease in nitrogen and phosphorus and consequent increase in C:N and C:P ratio in both ecosystems, along with the increase in polyphenolics and tannins in L. laureolum in the fynbos ecosystem, may negatively affect forage quality and decomposition rates. It is concluded that fast growing grasses do not experience sink limitation and invest extra carbon into growth rather than polyphenolics and

  6. Effect of Fe ion concentration on fatigue life of carbon steel in aqueous CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion fatigue behaviour of steel armours used in the flexible pipes, in aqueous solutions initially containing different concentrations of Fe2+, was investigated by four-point bending testing under saturated 1 bar CO2 condition. Corrosion fatigue results were supported with ......, fatigue samples experienced the same corrosion rate as samples that were not subjected to dynamic loading.......In this work, the corrosion fatigue behaviour of steel armours used in the flexible pipes, in aqueous solutions initially containing different concentrations of Fe2+, was investigated by four-point bending testing under saturated 1 bar CO2 condition. Corrosion fatigue results were supported with ex...... situ measurements of Fe2+ and pH. Characterisation of the corrosion scales and crack formations was performed using microscopic and diffraction techniques. Fatigue results showed two times better fatigue life, at the stress ranges of 250 MPa, for samples tested in solutions containing the concentration...

  7. Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate

    Science.gov (United States)

    Anagnostou, Eleni; John, Eleanor H.; Edgar, Kirsty M.; Foster, Gavin L.; Ridgwell, Andy; Inglis, Gordon N.; Pancost, Richard D.; Lunt, Daniel J.; Pearson, Paul N.

    2016-05-01

    The Early Eocene Climate Optimum (EECO, which occurred about 51 to 53 million years ago), was the warmest interval of the past 65 million years, with mean annual surface air temperature over ten degrees Celsius warmer than during the pre-industrial period. Subsequent global cooling in the middle and late Eocene epoch, especially at high latitudes, eventually led to continental ice sheet development in Antarctica in the early Oligocene epoch (about 33.6 million years ago). However, existing estimates place atmospheric carbon dioxide (CO2) levels during the Eocene at 500-3,000 parts per million, and in the absence of tighter constraints carbon-climate interactions over this interval remain uncertain. Here we use recent analytical and methodological developments to generate a new high-fidelity record of CO2 concentrations using the boron isotope (δ11B) composition of well preserved planktonic foraminifera from the Tanzania Drilling Project, revising previous estimates. Although species-level uncertainties make absolute values difficult to constrain, CO2 concentrations during the EECO were around 1,400 parts per million. The relative decline in CO2 concentration through the Eocene is more robustly constrained at about fifty per cent, with a further decline into the Oligocene. Provided the latitudinal dependency of sea surface temperature change for a given climate forcing in the Eocene was similar to that of the late Quaternary period, this CO2 decline was sufficient to drive the well documented high- and low-latitude cooling that occurred through the Eocene. Once the change in global temperature between the pre-industrial period and the Eocene caused by the action of all known slow feedbacks (apart from those associated with the carbon cycle) is removed, both the EECO and the late Eocene exhibit an equilibrium climate sensitivity relative to the pre-industrial period of 2.1 to 4.6 degrees Celsius per CO2 doubling (66 per cent confidence), which is similar to the

  8. Changing atmospheric CO2 concentration was the primary driver of early Cenozoic climate.

    Science.gov (United States)

    Anagnostou, Eleni; John, Eleanor H; Edgar, Kirsty M; Foster, Gavin L; Ridgwell, Andy; Inglis, Gordon N; Pancost, Richard D; Lunt, Daniel J; Pearson, Paul N

    2016-05-19

    The Early Eocene Climate Optimum (EECO, which occurred about 51 to 53 million years ago), was the warmest interval of the past 65 million years, with mean annual surface air temperature over ten degrees Celsius warmer than during the pre-industrial period. Subsequent global cooling in the middle and late Eocene epoch, especially at high latitudes, eventually led to continental ice sheet development in Antarctica in the early Oligocene epoch (about 33.6 million years ago). However, existing estimates place atmospheric carbon dioxide (CO2) levels during the Eocene at 500-3,000 parts per million, and in the absence of tighter constraints carbon-climate interactions over this interval remain uncertain. Here we use recent analytical and methodological developments to generate a new high-fidelity record of CO2 concentrations using the boron isotope (δ(11)B) composition of well preserved planktonic foraminifera from the Tanzania Drilling Project, revising previous estimates. Although species-level uncertainties make absolute values difficult to constrain, CO2 concentrations during the EECO were around 1,400 parts per million. The relative decline in CO2 concentration through the Eocene is more robustly constrained at about fifty per cent, with a further decline into the Oligocene. Provided the latitudinal dependency of sea surface temperature change for a given climate forcing in the Eocene was similar to that of the late Quaternary period, this CO2 decline was sufficient to drive the well documented high- and low-latitude cooling that occurred through the Eocene. Once the change in global temperature between the pre-industrial period and the Eocene caused by the action of all known slow feedbacks (apart from those associated with the carbon cycle) is removed, both the EECO and the late Eocene exhibit an equilibrium climate sensitivity relative to the pre-industrial period of 2.1 to 4.6 degrees Celsius per CO2 doubling (66 per cent confidence), which is similar to the

  9. Associations between classroom CO2 concentrations and student attendance in Washington and Idaho.

    Science.gov (United States)

    Shendell, D G; Prill, R; Fisk, W J; Apte, M G; Blake, D; Faulkner, D

    2004-10-01

    Student attendance in American public schools is a critical factor in securing limited operational funding. Student and teacher attendance influence academic performance. Limited data exist on indoor air and environmental quality (IEQ) in schools, and how IEQ affects attendance, health, or performance. This study explored the association of student absence with measures of indoor minus outdoor carbon dioxide concentration (dCO(2)). Absence and dCO(2) data were collected from 409 traditional and 25 portable classrooms from 22 schools located in six school districts in the states of Washington and Idaho. Study classrooms had individual heating, ventilation, and air conditioning (HVAC) systems, except two classrooms without mechanical ventilation. Classroom attributes, student attendance and school-level ethnicity, gender, and socioeconomic status (SES) were included in multivariate modeling. Forty-five percent of classrooms studied had short-term indoor CO(2) concentrations above 1000 p.p.m. A 1000 p.p.m. increase in dCO(2) was associated (P student absence. Annual ADA was 2% higher (P school studies to investigate associations of student attendance, and occupant health and student performance, with longer term indoor minus outdoor CO(2) concentrations and more accurately measured ventilation rates. If our findings are confirmed, improving classroom ventilation should be considered a practical means of reducing student absence. Adequate or enhanced ventilation may be achieved, for example, with educational training programs for teachers and facilities staff on ventilation system operation and maintenance. Also, technological interventions such as improved automated control systems could provide continuous ventilation during occupied times, regardless of occupant thermal comfort demands.

  10. Seasonal and diel variation in xylem CO2 concentration and sap pH in sub-Mediterranean oak stems.

    Science.gov (United States)

    Salomón, Roberto; Valbuena-Carabaña, María; Teskey, Robert; McGuire, Mary Anne; Aubrey, Doug; González-Doncel, Inés; Gil, Luis; Rodríguez-Calcerrada, Jesús

    2016-04-01

    Since a substantial portion of respired CO2 remains within the stem, diel and seasonal trends in stem CO2 concentration ([CO2]) are of major interest in plant respiration and carbon budget research. However, continuous long-term stem [CO2] studies are scarce, and generally absent in Mediterranean climates. In this study, stem [CO2] was monitored every 15min together with stem and air temperature, sap flow, and soil water storage during a growing season in 16 stems of Quercus pyrenaica to elucidate the main drivers of stem [CO2] at different temporal scales. Fluctuations in sap pH were also assessed during two growing seasons to evaluate potential errors in estimates of the concentration of CO2 dissolved in xylem sap ([CO2*]) calculated using Henry's law. Stem temperature was the best predictor of stem [CO2] and explained more than 90% and 50% of the variability in stem [CO2] at diel and seasonal scales, respectively. Under dry conditions, soil water storage was the main driver of stem [CO2]. Likewise, the first rains after summer drought caused intense stem [CO2] pulses, suggesting enhanced stem and root respiration and increased resistance to radial CO2 diffusion. Sap flow played a secondary role in controlling stem [CO2] variations. We observed night-time sap pH acidification and progressive seasonal alkalinization. Thus, if the annual mean value of sap pH (measured at midday) was assumed to be constant, night-time sap [CO2*] was substantially overestimated (40%), and spring and autumn sap [CO2*] were misestimated by 25%. This work highlights that diel and seasonal variations in temperature, tree water availability, and sap pH substantially affect xylem [CO2] and sap [CO2*]. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. [Study on the change of dune CO2 concentration in the autumn at Minqin in Tengger desert].

    Science.gov (United States)

    Shao, Tian-Jie; Zhao, Jing-Bo; Yu, Ke-Ke; Dong, Zhi-Bao

    2010-12-01

    In order to find out the CO2 concentration of the desert area, the influence of it on the CO2 in the atmosphere and the role that it played on the global carbon cycle, the research team utilized in September 2009 infrared CO2 monitor to observe the CO2 concentration of the 12 drill holes day and night in Minqin desert area in the Tengger desert. The difference of various observation spots' CO2 concentration of the desert area in the Tengger desert area is relatively big. The CO2 concentration at night is low but high in the daytime and the CO2 concentration at each observation spot changes from 310 x 10(-6) to 2 630 x 10(-6). The CO2 concentration is also obviously different in depth and the CO2 concentration at different depths in order of size is as follows: 4 m(3m) > 2 m > 1m. Compared with Xi' an area where is in the temperate and semi-humid region, the CO2 concentration of the desert area in Tengger desert is very low. The diurnal variation of CO2 concentration of the desert area in Tengger desert is obvious, and from the day 09:00 am to 09:00 am the next day, the CO2 concentrations at different depths which rang from 1 m to 4 m present the regularity that it changes from low to high, and then from high to low. The diurnal variation in temperature is the main reason that causes the change of the CO2 concentration in the sand layer, both of which have the positive correlation. The sand layer's CO2 concentration with higher water content is obviously higher than that with lower water content. The moisture content of sand layer is the main factor of the CO2 concentration. The CO2 concentration above 4m in the desert area is higher than that above the surface, which maybe indicates that the CO2 from the highest desert area is also the resource of CO2 in the atmosphere.

  12. Sensitivity of grapevine phenology to water availability, temperature and CO2 concentration

    Directory of Open Access Journals (Sweden)

    Johann Martínez-Lüscher

    2016-07-01

    Full Text Available In recent decades, mean global temperatures have increased in parallel with a sharp rise in atmospheric carbon dioxide (CO2 levels, with apparent implications for precipitation patterns. The aim of the present work is to assess the sensitivity of different phenological stages of grapevine to temperature and to study the influence of other factors related to climate change (water availability and CO2 concentration on this relationship. Grapevine phenological records from 9 plantings between 42.75°N and 46.03°N consisting of dates for budburst, flowering and fruit maturity were used. In addition, we used phenological data collected from two years of experiments with grapevine fruit-bearing cuttings with two grapevine varieties under two levels of water availability, two temperature regimes and two levels of CO2. Dormancy breaking and flowering were strongly dependent on spring temperature, while neither variation in temperature during the chilling period nor precipitation significantly affected budburst date. The time needed to reach fruit maturity diminished with increasing temperature and decreasing precipitation. Experiments under semi-controlled conditions revealed great sensitivity of berry development to both temperature and CO2. Water availability had significant interactions with both temperature and CO2; however, in general, water deficit delayed maturity when combined with other factors. Sensitivities to temperature and CO2 varied widely, but higher sensitivities appeared in the coolest year, particularly for the late ripening variety, ‘White Tempranillo’. The knowledge gained in whole plant physiology and multi stress approaches is crucial to predict the effects of climate change and to design mitigation and adaptation strategies allowing viticulture to cope with climate change.

  13. Commercial Non-Dispersive Infrared Spectroscopy Sensors for Sub-Ambient Carbon Dioxide Detection

    Science.gov (United States)

    Swickrath, Michael J.; Anderson, Molly S.; McMillin, Summer; Broerman, Craig

    2013-01-01

    Carbon dioxide produced through respiration can accumulate rapidly within closed spaces. If not managed, a crew's respiratory rate increases, headaches and hyperventilation occur, vision and hearing are affected, and cognitive abilities decrease. Consequently, development continues on a number of CO2 removal technologies for human spacecraft and spacesuits. Terrestrially, technology development requires precise performance characterization to qualify promising air revitalization equipment. On-orbit, instrumentation is required to identify and eliminate unsafe conditions. This necessitates accurate in situ CO2 detection. Recursive compensation algorithms were developed for sub-ambient detection of CO2 with commercial off-the-shelf (COTS) non-dispersive infrared (NDIR) sensors. In addition, the source of the exponential loss in accuracy is developed theoretically. The basis of the loss can be explained through thermal, Doppler, and Lorentz broadening effects that arise as a result of the temperature, pressure, and composition of the gas mixture under analysis. The objective was to develop a mathematical routine to compensate COTS CO2 sensors relying on NDIR over pressures, temperatures, and compositions far from calibration conditions. The routine relies on a power-law relationship for the pressure dependency of the sensors along with an equivalent pressure to account for the composition dependency. A Newton-Raphson iterative technique solves for actual carbon dioxide concentration based on the reported concentration. Moreover, first principles routines were established to predict mixed-gas spectra based on sensor specifications (e.g., optical path length). The first principles model can be used to parametrically optimize sensors or sensor arrays across a wide variety of pressures/temperatures/ compositions. In this work, heuristic scaling arguments were utilized to develop reasonable compensation techniques. Experimental results confirmed this approach and provided

  14. Unexpected effect of catalyst concentration on photochemical CO2reduction bytrans(Cl)-Ru(bpy)(CO)2Cl2: new mechanistic insight into the CO/HCOO-selectivity.

    Science.gov (United States)

    Kuramochi, Yusuke; Itabashi, Jun; Fukaya, Kyohei; Enomoto, Akito; Yoshida, Makoto; Ishida, Hitoshi

    2015-05-01

    Photochemical CO 2 reduction catalysed by trans (Cl)-Ru(bpy)(CO) 2 Cl 2 (bpy = 2,2'-bipyridine) efficiently produces carbon monoxide (CO) and formate (HCOO - ) in N , N -dimethylacetamide (DMA)/water containing [Ru(bpy) 3 ] 2+ as a photosensitizer and 1-benzyl-1,4-dihydronicotinamide (BNAH) as an electron donor. We have unexpectedly found catalyst concentration dependence of the product ratio (CO/HCOO - ) in the photochemical CO 2 reduction: the ratio of CO/HCOO - decreases with increasing catalyst concentration. The result has led us to propose a new mechanism in which HCOO - is selectively produced by the formation of a Ru(i)-Ru(i) dimer as the catalyst intermediate. This reaction mechanism predicts that the Ru-Ru bond dissociates in the reaction of the dimer with CO 2 , and that the insufficient electron supply to the catalyst results in the dominant formation of HCOO - . The proposed mechanism is supported by the result that the time-course profiles of CO and HCOO - in the photochemical CO 2 reduction catalysed by [Ru(bpy)(CO) 2 Cl] 2 (0.05 mM) are very similar to those of the reduction catalysed by trans (Cl)-Ru(bpy)(CO) 2 Cl 2 (0.10 mM), and that HCOO - formation becomes dominant under low-intensity light. The kinetic analyses based on the proposed mechanism could excellently reproduce the unusual catalyst concentration effect on the product ratio. The catalyst concentration effect observed in the photochemical CO 2 reduction using [Ru(4dmbpy) 3 ] 2+ (4dmbpy = 4,4'-dimethyl-2,2'-bipyridine) instead of [Ru(bpy) 3 ] 2+ as the photosensitizer is also explained with the kinetic analyses, reflecting the smaller quenching rate constant of excited [Ru(4dmbpy) 3 ] 2+ by BNAH than that of excited [Ru(bpy) 3 ] 2+ . We have further synthesized trans (Cl)-Ru(6Mes-bpy)(CO) 2 Cl 2 (6Mes-bpy = 6,6'-dimesityl-2,2'-bipyridine), which bears bulky substituents at the 6,6'-positions in the 2,2'-bipyridyl ligand, so that the ruthenium complex cannot form the dimer due to the

  15. The Chlamydomonas CO2 -concentrating mechanism and its potential for engineering photosynthesis in plants.

    Science.gov (United States)

    Mackinder, Luke C M

    2018-01-01

    Contents Summary I. Introduction 54 II. Recent advances in our understanding of the Chlamydomonas CCM 55 III. Current gaps in our understanding of the Chlamydomonas CCM 58 IV. Approaches to rapidly advance our understanding of the Chlamydomonas CCM 58 V. Engineering a CCM into higher plants 58 VI. Conclusion and outlook 59 Acknowledgements 60 References 60 SUMMARY: To meet the food demands of a rising global population, innovative strategies are required to increase crop yields. Improvements in plant photosynthesis by genetic engineering show considerable potential towards this goal. One prospective approach is to introduce a CO2 -concentrating mechanism into crop plants to increase carbon fixation by supplying the central carbon-fixing enzyme, Rubisco, with a higher concentration of its substrate, CO2 . A promising donor organism for the molecular machinery of this mechanism is the eukaryotic alga Chlamydomonas reinhardtii. This review summarizes the recent advances in our understanding of carbon concentration in Chlamydomonas, outlines the most pressing gaps in our knowledge and discusses strategies to transfer a CO2 -concentrating mechanism into higher plants to increase photosynthetic performance. © 2017 The Author. New Phytologist © 2017 New Phytologist Trust.

  16. Diel variation in gene expression of the CO2-concentrating mechanism during a harmful cyanobacterial bloom

    Directory of Open Access Journals (Sweden)

    Giovanni eSandrini

    2016-04-01

    Full Text Available Dense phytoplankton blooms in eutrophic waters often experience large daily fluctuations in environmental conditions. We investigated how this diel variation affects in situ gene expression of the CO2-concentrating mechanism (CCM and other selected genes of the harmful cyanobacterium Microcystis aeruginosa. Photosynthetic activity of the cyanobacterial bloom depleted the dissolved CO2 concentration, raised pH to 10, and caused large diel fluctuations in the bicarbonate and O2 concentration. The Microcystis population consisted of three Ci uptake genotypes that differed in the presence of the low-affinity and high-affinity bicarbonate uptake genes bicA and sbtA. Expression of the bicarbonate uptake genes bicA, sbtA and cmpA (encoding a subunit of the high-affinity bicarbonate uptake system BCT1, the CCM transcriptional regulator gene ccmR and the photoprotection gene flv4 increased at first daylight and was negatively correlated with the bicarbonate concentration. In contrast, genes of the two CO2 uptake systems were constitutively expressed, whereas expression of the RuBisCO chaperone gene rbcX, the carboxysome gene ccmM, and the photoprotection gene isiA was highest at night and down-regulated during daytime. In total, our results show that the harmful cyanobacterium Microcystis is very responsive to the large diel variations in carbon and light availability often encountered in dense cyanobacterial blooms.

  17. Diel Variation in Gene Expression of the CO2-Concentrating Mechanism during a Harmful Cyanobacterial Bloom.

    Science.gov (United States)

    Sandrini, Giovanni; Tann, Robert P; Schuurmans, J Merijn; van Beusekom, Sebastiaan A M; Matthijs, Hans C P; Huisman, Jef

    2016-01-01

    Dense phytoplankton blooms in eutrophic waters often experience large daily fluctuations in environmental conditions. We investigated how this diel variation affects in situ gene expression of the CO2-concentrating mechanism (CCM) and other selected genes of the harmful cyanobacterium Microcystis aeruginosa. Photosynthetic activity of the cyanobacterial bloom depleted the dissolved CO2 concentration, raised pH to 10, and caused large diel fluctuations in the bicarbonate and O2 concentration. The Microcystis population consisted of three Ci uptake genotypes that differed in the presence of the low-affinity and high-affinity bicarbonate uptake genes bicA and sbtA. Expression of the bicarbonate uptake genes bicA, sbtA, and cmpA (encoding a subunit of the high-affinity bicarbonate uptake system BCT1), the CCM transcriptional regulator gene ccmR and the photoprotection gene flv4 increased at first daylight and was negatively correlated with the bicarbonate concentration. In contrast, genes of the two CO2 uptake systems were constitutively expressed, whereas expression of the RuBisCO chaperone gene rbcX, the carboxysome gene ccmM, and the photoprotection gene isiA was highest at night and down-regulated during daytime. In total, our results show that the harmful cyanobacterium Microcystis is very responsive to the large diel variations in carbon and light availability often encountered in dense cyanobacterial blooms.

  18. Laser Sounder for Global Measurement of CO2 Concentrations in the Troposphere from Space: Progress

    Science.gov (United States)

    Abshire, J. B.; Krainak, M.; Riris, H. J.; Sun, X.; Riris, H.; Andrews, A. E.; Collatz, J.

    2004-01-01

    We describe progress toward developing a laser-based technique for the remote measurement of the tropospheric CO2 concentrations from orbit. Our goal is to demonstrate a lidar technique and instrument technology that will permit measurements of the CO2 column abundance in the lower troposphere from aircraft at the few ppm level, with a capability of scaling to permit global CO2 measurements from orbit. Accurate measurements of the tropospheric CO2 mixing ratio from space are challenging due to the many potential error sources. These include possible interference from other trace gas species, the effects of temperature, clouds, aerosols & turbulence in the path, changes in surface reflectivity, and variability in dry air density caused by changes in atmospheric pressure, water vapor and topographic height. Some potential instrumental errors include frequency drifts in the transmitter, small transmission and sensitivity drifts in the instrument. High signal-to-noise ratios and measurement stability are needed for mixing ratio estimates at the few ppm level. We have been developing a laser sounder approach as a candidate for a future space mission. It utilizes multiple different laser transmitters to permit simultaneous measurement of CO2 and O2 extinction, and aerosol backscatter in the same measurement path. It directs the narrow co-aligned laser beams from the instrument's fiber lasers toward nadir, and measures the energy of the strong laser echoes reflected from the Earth's land and water surfaces. During the measurement its narrow linewidth lasers are rapidly tuned on- and off- selected CO2 line near 1572 nm and an O2 absorption line near 770 nm. The receiver measures the energies of the laser echoes from the surface and any clouds and aerosols in the path with photon counting detectors. Ratioing the on- to off-line echo pulse energies for each gas permits the column extinction and column densities of CO2 and O2 to be estimated simultaneously via the

  19. [Measurements of CO2 Concentration Profile in Troposphere Based on Balloon-Borne TDLAS System].

    Science.gov (United States)

    Yao, Lu; Liu, Wen-qing; Liu, Jian-guo; Kan, Rui-feng; Xu, Zhen-yu; Ruan, Jun; Yuan, Song

    2015-10-01

    The main source and sink of CO2 in the atmosphere are concentrated in the troposphere. It is of great significance to the study of CO2 flux and global climate change to obtain the accurate tropospheric CO2 concentration profile. For the characteristics of high resolution, high sensitivity and fast response of tunable diode laser absorption spectroscopy (TDLAS), a compact balloon-borne system based on direct absorption was developed to detect the CO2 concentration profiles by use of the 2 004. 02 nm, R(16), v1+v3 line without the interfere of H2O absorption and the CO2 density of the number of molecules below 10 km in the troposphere was obtained. Due to the balloon-borne environment, a compact design of one single board integrated with laser driver, signal conditioning, spectra acquiring and concentration retrieving was developed. Limited by the working capability and hardware resources of embedded micro-processor, the spectra processing algorithm was optimized to reduce the time-cost. Compared with the traditional TDLAS sensors with WMS technique, this system was designed based on the direct absorption technique by means of an open-path Herriott cell with 20 m optical-path, which avoided the process of standardization and enhanced the environmental adaptation. The universal design of hardware and software platform achieved diverse gas measuring by changing the laser and adjusting some key parameters in algorithm. The concept of compact design helped to reduce the system's power and volume and balanced the response speed and measure precision. The power consumes below 1.5 W in room temperature and the volume of the single board is 120 mm x 100 mm x 25 mm, and the measurement accuracy is ± 0.6 x 10(-6) at 1.5 s response time. It has been proved that the system can realize high precision detection of CO2 profile at 15 m vertical resolution in troposphere and TDLAS is an available method for balloon-borne detection.

  20. Increasing atmospheric humidity and CO2 concentration alleviate forest hydraulic failure risk

    Science.gov (United States)

    Liu, Y.; Parolari, A.; Kumar, M.; Porporato, A. M.; Katul, G. G.

    2016-12-01

    Climate-induced forest mortality is being observed throughout the globe and has the potential to alter ecosystem services provided by forests. Recent studies suggest that forest mortality is expected to be exacerbated under climate change due to intensified water and heat stress. While few dispute the claim that the compound effect of reduced soil water and increased heat stress increases the probability of forest mortality, impacts of other aspects of climate change have not been explored. Specifically, the impacts of concurrent changes in atmospheric humidity and atmospheric CO2 concentration, which may influence stomatal kinetics in ways that allow plants to operate despite reduced plant hydraulic capacity, remain unaddressed. Here, the risk of hydraulic failure (HFR), one of the key factors contributing to forest mortality is investigated by setting up a dynamic soil-plant-atmospheric model. The coupled and isolated responses of HFR to changes in precipitation amount and seasonality, air temperature, atmospheric humidity, and atmospheric CO2 concentration are analyzed. By incorporating CMIP5 climate projections, the synthetic future responses of HFR for 13 forest biomes across the globe are examined. The results indicate that while HFR is predicted to increase under shifting precipitation patterns and elevated air temperature, the increasing risks may be partly compensated by increases in atmospheric humidity and CO2 concentration. The alleviating effects are likely to be more significant for broadleaf forests than those for needleleaf forests. Our findings suggest that contributions of atmospheric humidity and CO2 concentration on HFR, independently of other effects such as seed production, germination, spread, disease outbreak, and resource competition at the community level, may lead to lower risks of forest mortality than previously thought.

  1. Increasing atmospheric humidity and CO2 concentration alleviate forest mortality risk.

    Science.gov (United States)

    Liu, Yanlan; Parolari, Anthony J; Kumar, Mukesh; Huang, Cheng-Wei; Katul, Gabriel G; Porporato, Amilcare

    2017-09-12

    Climate-induced forest mortality is being increasingly observed throughout the globe. Alarmingly, it is expected to exacerbate under climate change due to shifting precipitation patterns and rising air temperature. However, the impact of concomitant changes in atmospheric humidity and CO2 concentration through their influence on stomatal kinetics remains a subject of debate and inquiry. By using a dynamic soil-plant-atmosphere model, mortality risks associated with hydraulic failure and stomatal closure for 13 temperate and tropical forest biomes across the globe are analyzed. The mortality risk is evaluated in response to both individual and combined changes in precipitation amounts and their seasonal distribution, mean air temperature, specific humidity, and atmospheric CO2 concentration. Model results show that the risk is predicted to significantly increase due to changes in precipitation and air temperature regime for the period 2050-2069. However, this increase may largely get alleviated by concurrent increases in atmospheric specific humidity and CO2 concentration. The increase in mortality risk is expected to be higher for needleleaf forests than for broadleaf forests, as a result of disparity in hydraulic traits. These findings will facilitate decisions about intervention and management of different forest types under changing climate.

  2. Short-term carbon cycling responses of a mature eucalypt woodland to gradual stepwise enrichment of atmospheric CO2 concentration.

    Science.gov (United States)

    Drake, John E; Macdonald, Catriona A; Tjoelker, Mark G; Crous, Kristine Y; Gimeno, Teresa E; Singh, Brajesh K; Reich, Peter B; Anderson, Ian C; Ellsworth, David S

    2016-01-01

    Projections of future climate are highly sensitive to uncertainties regarding carbon (C) uptake and storage by terrestrial ecosystems. The Eucalyptus Free-Air CO2 Enrichment (EucFACE) experiment was established to study the effects of elevated atmospheric CO2 concentrations (eCO2 ) on a native mature eucalypt woodland with low fertility soils in southeast Australia. In contrast to other FACE experiments, the concentration of CO2 at EucFACE was increased gradually in steps above ambient (+0, 30, 60, 90, 120, and 150 ppm CO2 above ambient of ~400 ppm), with each step lasting approximately 5 weeks. This provided a unique opportunity to study the short-term (weeks to months) response of C cycle flux components to eCO2 across a range of CO2 concentrations in an intact ecosystem. Soil CO2 efflux (i.e., soil respiration or Rsoil ) increased in response to initial enrichment (e.g., +30 and +60 ppm CO2 ) but did not continue to increase as the CO2 enrichment was stepped up to higher concentrations. Light-saturated photosynthesis of canopy leaves (Asat ) also showed similar stimulation by elevated CO2 at +60 ppm as at +150 ppm CO2 . The lack of significant effects of eCO2 on soil moisture, microbial biomass, or activity suggests that the increase in Rsoil likely reflected increased root and rhizosphere respiration rather than increased microbial decomposition of soil organic matter. This rapid increase in Rsoil suggests that under eCO2, additional photosynthate was produced, transported belowground, and respired. The consequences of this increased belowground activity and whether it is sustained through time in mature ecosystems under eCO2 are a priority for future research. © 2015 John Wiley & Sons Ltd.

  3. Laser Sounder Approach for Measuring Atmospheric CO2 Concentrations for the ASCENDS Mission

    Science.gov (United States)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Sun, X.; Wilson, E.; Stephen, M. A.; Weaver, C.

    2008-12-01

    Accurate measurements of tropospheric CO2 abundances with global-coverage and monthly temporal resolution are needed to quantify processes that regulate CO2 exchange with the land and oceans. To meet this need, the 2007 Decadal Survey for Earth Science by the US National Research Council recommended a laser-based CO2 measuring mission called ASCENDS. In July 2008 NASA convened a science definition workshop for ASCENDS, which helped better define the mission and measurement requirements. We have been developing a technique for the remote measurement of tropospheric CO2 concentrations from aircraft and spacecraft. Our immediate goal is to develop and demonstrate the lidar technique and technology that will permit measurements of the CO2 column abundance over horizontal paths and from aircraft at the few-ppmv level. Our longer-term goal is to demonstrate the capabilities of the technique and instrument design needed for an ASCENDS-type mission. Our approach uses the 1570-nm band and a dual channel laser absorption spectrometer (ie DIAL used in altimeter mode). It uses several tunable fiber laser transmitters allowing simultaneous measurement of the absorption from a CO2 absorption line in the 1570 nm band, O2 extinction in the oxygen A-band, and surface height and aerosol backscatter in the same path. It directs the narrow co-aligned laser beams toward nadir, and measures the energy of the laser echoes reflected from land and water surfaces. The lasers are tuned on and off the sides of CO2 line and an O2 line (near 765 nm) at kHz rates. The receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of the on and off line signals via the DIAL technique. We use pulsed laser signals and time gating to isolate the laser echo signals from the

  4. Forsterite Carbonation in Wet-scCO2: Dependence on Adsorbed Water Concentration

    Science.gov (United States)

    Loring, J.; Benezeth, P.; Qafoku, O.; Thompson, C.; Schaef, T.; Bonneville, A.; McGrail, P.; Felmy, A.; Rosso, K.

    2013-12-01

    Capturing and storing CO2 in basaltic formations is one of the most promising options for mitigating atmospheric CO2 emissions resulting from the burning of fossil fuels. These geologic reservoirs have high reactive potential for CO2-mineral trapping due to an abundance of divalent-cation containing silicates, such as forsterite (Mg2SiO4). Recent studies have shown that carbonation of these silicates under wet scCO2 conditions, e. g. encountered near a CO2 injection well, proceeds along a different pathway and is more effective than in CO2-saturated aqueous fluids. The presence of an adsorbed water film on the forsterite surface seems to be key to reactivity towards carbonation. In this study, we employed in situ high pressure IR spectroscopy to investigate the dependence of adsorbed water film thickness on forsterite carbonation chemistry. Post reaction ex situ SEM, TEM, TGA, XRD, and NMR measurements will also be discussed. Several IR titrations were performed of forsterite with water at 50 °C and 90 bar scCO2. Aliquots of water were titrated at 4-hour reaction-time increments. Once a desired total water concentration was reached, data were collected for about another 30 hours. One titration involved 10 additions, which corresponds to 6.8 monolayers of adsorbed water. Clearly, a carbonate was precipitating, and its spectral signature matched magnesite. Another titration involved 8 aliquots, or up to 4.4 monolayers of water. The integrated absorbance under the CO stretching bands of carbonate as a function of time after reaching 4.4 monolayers showed an increase and then a plateau. We are currently unsure of the identity of the carbonate that precipitated, but it could be an amorphous anhydrous phase or magnesite crystals with dimensions of only several nanometers. A third titration only involved 3 additions, or up to 1.6 monolayers of water. The integrated absorbance under the CO stretching bands of carbonate as a function of time after reaching 1.6 monolayers

  5. Effects of elevated CO2 concentration and water deficit on fructan metabolism in Viguiera discolor Baker.

    Science.gov (United States)

    Oliveira, V F; Silva, E A; Zaidan, L B P; Carvalho, M A M

    2013-05-01

    Elevated [CO2 ] is suggested to mitigate the negative effects of water stress in plants; however responses vary among species. Fructans are recognised as protective compounds against drought and other stresses, as well as having a role as reserve carbohydrates. We analysed the combined effects of elevated [CO2 ] and water deficit on fructan metabolism in the Cerrado species Viguiera discolor Baker. Plants were cultivated for 18 days in open-top chambers (OTC) under ambient (∼380 ppm), and high (∼760 ppm) [CO2 ]. In each OTC, plants were submitted to three treatments: (i) daily watering (control), (ii) withholding water (WS) for 18 days and (iii) re-watering (RW) on day 11. Analyses were performed at time 0 and days 5, 8, 11, 15 and 18. High [CO2 ] increased photosynthesis in control plants and increased water use efficiency in WS plants. The decline in soil water content was more distinct in WS 760 (WS under 760 ppm), although the leaf and tuberous root water status was similar to WS 380 plants (WS under 380 ppm). Regarding fructan active enzymes, 1-SST activity decreased in WS plants in both CO2 concentrations, a result consistent with the decline in photosynthesis and, consequently, in substrate availability. Under WS and both [CO2 ] treatments, 1-FFT and 1-FEH seemed to act in combination to generate osmotically active compounds and thus overcome water deficit. The proportion of hexoses to sucrose, 1-kestose and nystose (SKN) was higher in WS plants. In WS 760, this increase was higher than in WS 380, and was not accompanied by decreases in SKN at the beginning of the treatment, as observed in WS 380 plants. These results suggest that the higher [CO2 ] in the atmosphere contributed to maintain, for a longer period, the pool of hexoses and of low DP fructans, favouring the maintenance of the water status and plant survival under drought. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  6. Laser Sounder for Global Measurement of CO2 Concentrations in the Troposphere from Space

    Science.gov (United States)

    Abshire, James B.; Riris, Haris; Kawa, S. Randy; Sun, Xiaoli; Chen, Jeffrey; Stephen, Mark A.; Collatz, G. James; Mao, Jianping; Allan, Graham

    2007-01-01

    Measurements of tropospheric CO2 abundance with global-coverage, a few hundred km spatial and monthly temporal resolution are needed to quantify processes that regulate CO2 storage by the land and oceans. The Orbiting Carbon Observatory (OCO) is the first space mission focused on atmospheric CO2 for measuring total column CO, and O2 by detecting the spectral absorption in reflected sunlight. The OCO mission is an essential step, and will yield important new information about atmospheric CO2 distributions. However there are unavoidable limitations imposed by its measurement approach. These include best accuracy only during daytime at moderate to high sun angles, interference by cloud and aerosol scattering, and limited signal from CO2 variability in the lower tropospheric CO2 column. We have been developing a new laser-based technique for the remote measurement of the tropospheric CO2 concentrations from orbit. Our initial goal is to demonstrate a lidar technique and instrument technology that will permit measurements of the CO2 column abundance in the lower troposphere from aircraft. Our final goal is to develop a space instrument and mission approach for active measurements of the CO2 mixing ratio at the 1-2 ppmv level. Our technique is much less sensitive to cloud and atmospheric scattering conditions and would allow continuous measurements of CO2 mixing ratio in the lower troposphere from orbit over land and ocean surfaces during day and night. Our approach is to use the 1570nm CO2 band and a 3-channel laser absorption spectrometer (i.e. lidar used an altimeter mode), which continuously measures at nadir from a near polar circular orbit. The approach directs the narrow co-aligned laser beams from the instrument's lasers toward nadir, and measures the energy of the laser echoes reflected from land and water surfaces. It uses several tunable fiber laser transmitters which allowing measurement of the extinction from a single selected CO2 absorption line in the 1570

  7. Effect of CO2 Concentration on Growth and Biochemical Composition of Newly Isolated Indigenous Microalga Scenedesmus bajacalifornicus BBKLP-07.

    Science.gov (United States)

    Patil, Lakkanagouda; Kaliwal, Basappa

    2017-05-01

    Photosynthetic mitigation of CO2 through microalgae is gaining great importance due to its higher photosynthetic ability compared to plants, and the biomass can be commercially exploited for various applications. CO2 fixation capability of the newly isolated freshwater microalgae Scenedesmus bajacalifornicus BBKLP-07 was investigated using a 1-l photobioreactor. The cultivation was carried at varying concentration of CO2 ranging from 5 to 25%, and the temperature and light intensities were kept constant. A maximum CO2 fixation rate was observed at 15% CO2 concentration. Characteristic growth parameters such as biomass productivity, specific growth rate, and maximum biomass yield, and biochemical parameters such as carbohydrate, protein, lipid, chlorophyll, and carotenoid were determined and discussed. It was observed that the effect of CO2 concentration on growth and biochemical composition was quite significant. The maximum biomass productivity was 0.061 ± 0.0007 g/l/day, and the rate of CO2 fixation was 0.12 ± 0.002 g/l/day at 15% CO2 concentration. The carbohydrate and lipid content were maximum at 25% CO2 with 26.19 and 25.81% dry cell weight whereas protein, chlorophyll, and carotenoid contents were 32.89% dry cell weight, 25.07 μg/ml and 6.15 μg/ml respectively at 15% CO2 concentration.

  8. Interactions Between Temperature and Intercellular CO2 Concentration in Controlling Leaf Isoprene Emission Rates

    Science.gov (United States)

    Monson, Russell K.; Neice, Amberly A.; Trahan, Nicole A.; Shiach, Ian; McCorkel, Joel T.; Moore, David J. P.

    2016-01-01

    Plant isoprene emissions have been linked to several reaction pathways involved in atmospheric photochemistry. Evidence exists from a limited set of past observations that isoprene emission rate (I(sub s)) decreases as a function of increasing atmospheric CO2 concentration, and that increased temperature suppresses the CO2 effect. We studied interactions between intercellular CO2 concentration (C(sub I)) and temperature as they affect I(sub s) in field-grown hybrid poplar trees in one of the warmest climates on earth - the Sonoran Desert of the southwestern United States. We observed an unexpected midsummer down regulation of I(sub s) despite the persistence of relatively high temperatures. High temperature suppression of the I(sub s):C(sub I) relation occurred at all times during the growing season, but sensitivity of I(sub s) to increased C(sub I) was greatest during the midsummer period when I(subs) was lowest. We interpret the seasonal down regulation of I(sub s) and increased sensitivity of I(sub s) to C(sub I) as being caused by weather changes associated with the onset of a regional monsoon system. Our observations on the temperature suppression of the I(sub s):C(sub I) relation are best explained by the existence of a small pool of chloroplastic inorganic phosphate, balanced by several large, connected metabolic fluxes, which together, determine the C(sub I) and temperature dependencies of phosphoenolpyruvate import into the chloroplast.

  9. Plant growth and leaf-spot severity on eucalypt at different CO2 concentrations in the air

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Oliveira da Silva

    2014-03-01

    Full Text Available The objective of this work was to evaluate the effects of increased air-CO2 concentration on plant growth and on leaf-spot caused by Cylindrocladium candelabrum in Eucalyptus urophylla. Seedlings were cultivated for 30 days at 451, 645, 904, and 1,147 µmol mol-1 CO2 ; then, they were inoculated with the pathogen and kept under the same conditions for seven days. Increased CO2 concentration increased plant height and shoot dry matter mass, and decreased disease incidence and severity. Stem diameter was not affected by the treatments. Increased concentrations of atmospheric CO2 favorably affect eucalypt growth and reduce leaf-spot severity.

  10. Low concentration CO2 capture using physical adsorbents: Are Metal-Organic Frameworks becoming the new benchmark materials?

    KAUST Repository

    Belmabkhout, Youssef

    2016-03-30

    The capture and separation of traces and concentrated CO2 from important commodities such as CH4, H2, O2 and N2, is becoming important in many areas related to energy security and environmental sustainability. While trace CO2 concentration removal applications have been modestly studied for decades, the spike in interest in the capture of concentrated CO2 was motivated by the need for new energy vectors to replace highly concentrated carbon fuels and the necessity to reduce emissions from fossil fuel-fired power plants. CO2 capture from various gas streams, at different concentrations, using physical adsorbents, such as activated carbon, zeolites, and metal-organic frameworks (MOFs), is attractive. However, the adsorbents must be designed with consideration of many parameters including CO2 affinity, kinetics, energetics, stability, capture mechanism, in addition to cost. Here, we perform a systematic analysis regarding the key technical parameters that are required for the best CO2 capture performance using physical adsorbents. We also experimentally demonstrate a suitable material model of Metal Organic Framework as advanced adsorbents with unprecedented properties for CO2 capture in a wide range of CO2 concentration. These recently developed class of MOF adsorbents represent a breakthrough finding in the removal of traces CO2 using physical adsorption. This platform shows colossal tuning potential for more efficient separation agents.

  11. [Characteristics of atmospheric CO2 concentration and variation of carbon source & sink at Lin'an regional background station].

    Science.gov (United States)

    Pu, Jing-Jiao; Xu, Hong-Hui; Kang, Li-Li; Ma, Qian-Li

    2011-08-01

    Characteristics of Atmospheric CO2 concentration obtained by Flask measurements were analyzed at Lin'an regional background station from August 2006 to July 2009. According to the simulation results of carbon tracking model, the impact of carbon sources and sinks on CO2 concentration was evaluated in Yangtze River Delta. The results revealed that atmospheric CO2 concentrations at Lin'an regional background station were between 368.3 x 10(-6) and 414.8 x 10(-6). The CO2 concentration varied as seasons change, with maximum in winter and minimum in summer; the annual difference was about 20.5 x 10(-6). The long-term trend of CO2 concentration showed rapid growth year by year; the average growth rate was about 3.2 x 10(-6)/a. CO2 flux of Yangtze River Delta was mainly contributed by fossil fuel burning, terrestrial biosphere exchange and ocean exchange, while the contribution of fire emission was small. CO2 flux from fossil fuel burning played an important role in carbon source; terrestrial biosphere and ocean were important carbon sinks in this area. Seasonal variations of CO2 concentration at Lin'an regional background station were consistent with CO2 fluxes from fossil fuel burning and terrestrial biosphere exchange.

  12. Effects of elevated temperature and CO2 concentration on photosynthesis of the alpine plants in Zoige Plateau, China

    Science.gov (United States)

    Zijuan, Zhou; Peixi, Su; Rui, Shi; Tingting, Xie

    2017-04-01

    Increasing temperature and carbon dioxide concentration are the important aspects of global climate change. Alpine ecosystem response to global change was more sensitive and rapid than other ecosystems. Increases in temperature and atmospheric CO2concentrations have strong impacts on plant physiology. Photosynthesis is the basis for plant growth and the decisive factor for the level of productivity, and also is a very sensitive physiological process to climate change. In this study, we examined the interactive effects of elevated temperature and atmospheric CO2 concentration on the light response of photosynthesis in two alpine plants Elymus nutans and Potentilla anserine, which were widely distributed in alpine meadow in the Zoige Plateau, China. We set up as follows: the control (Ta 20˚ C, CO2 380μmolṡmol-1), elevated temperature (Ta 25˚ C, CO2 380 μmolṡmol-1), elevated CO2 concentration (Ta 20˚ C, CO2 700μmolṡmol-1), elevated temperature and CO2 concentration (Ta 25˚ C, CO2 700μmolṡmol-1). The results showed that compared to P. anserine, E. nutans had a higher maximum net photosynthetic rate (Pnmax), light saturation point (LSP) and apparent quantum yield (AQY) in the control. Elevated temperature increased the Pnmaxand LSP values in P. anserine, while Pnmaxand LSP were decreased in E. nutans. Elevated CO2 increased the Pnmaxand LSP values in E. nutans and P. anserine, while the light compensation point (LCP) decreased; Elevated both temperature and CO2, the Pnmaxand LSP were all increased for E. nutans and P. anserine, but did not significantly affect AQY. We concluded that although elevated temperature had a photoinhibition for E. nutans, the interaction of short-term elevated CO2 concentration and temperature can improve the photosynthetic capacity of alpine plants. Key Words: elevated temperature; CO2 concentration; light response; alpine plants

  13. Changes in the salinity tolerance of sweet pepper plants as affected by nitrogen form and high CO2 concentration.

    Science.gov (United States)

    Piñero, María C; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2016-08-01

    The assimilation and availability of nitrogen in its different forms can significantly affect the response of primary productivity under the current atmospheric alteration and soil degradation. An elevated CO2 concentration (e[CO2]) triggers changes in the efficiency and efficacy of photosynthetic processes, water use and product yield, the plant response to stress being altered with respect to ambient CO2 conditions (a[CO2]). Additionally, NH4(+) has been related to improved plant responses to stress, considering both energy efficiency in N-assimilation and the overcoming of the inhibition of photorespiration at e[CO2]. Therefore, the aim of this work was to determine the response of sweet pepper plants (Capsicum annuum L.) receiving an additional supply of NH4(+) (90/10 NO3(-)/NH4(+)) to salinity stress (60mM NaCl) under a[CO2] (400μmolmol(-1)) or e[CO2] (800μmolmol(-1)). Salt-stressed plants grown at e[CO2] showed DW accumulation similar to that of the non-stressed plants at a[CO2]. The supply of NH4(+) reduced growth at e[CO2] when salinity was imposed. Moreover, NH4(+) differentially affected the stomatal conductance and water use efficiency and the leaf Cl(-), K(+), and Na(+) concentrations, but the extent of the effects was influenced by the [CO2]. An antioxidant-related response was prompted by salinity, the total phenolics and proline concentrations being reduced by NH4(+) at e[CO2]. Our results show that the effect of NH4(+) on plant salinity tolerance should be globally re-evaluated as e[CO2] can significantly alter the response, when compared with previous studies at a[CO2]. Copyright © 2016 Elsevier GmbH. All rights reserved.

  14. Amelioration of boron toxicity in sweet pepper as affected by calcium management under an elevated CO2 concentration.

    Science.gov (United States)

    Piñero, María Carmen; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2017-04-01

    We investigated B tolerance in sweet pepper plants (Capsicum annuun L.) under an elevated CO2 concentration, combined with the application of calcium as a nutrient management amelioration technique. The data show that high B affected the roots more than the aerial parts, since there was an increase in the shoot/root ratio, when plants were grown with high B levels; however, the impact was lessened when the plants were grown at elevated CO2, since the root FW reduction caused by excess B was less marked at the high CO2 concentration (30.9% less). Additionally, the high B concentration affected the membrane permeability of roots, which increased from 39 to 54% at ambient CO2 concentration, and from 38 to 51% at elevated CO2 concentration, producing a cation imbalance in plants, which was differentially affected by the CO2 supply. The Ca surplus in the nutrient solution reduced the nutritional imbalance in sweet pepper plants produced by the high B concentration, at both CO2 concentrations. The medium B concentration treatment (toxic according to the literature) did not result in any toxic effect. Hence, there is a need to review the literature on critical and toxic B levels taking into account increases in atmospheric CO2.

  15. Milk pH as a function of CO2 concentration, temperature, and pressure in a heat exchanger.

    Science.gov (United States)

    Ma, Y; Barbano, D M

    2003-12-01

    Raw skim milk, with or without added CO2, was heated, held, and cooled in a small pilot-scale tubular heat exchanger (372 ml/min). The experiment was replicated twice, and, for each replication, milk was first carbonated at 0 to 1 degree C to contain 0 (control), 600, 1200, 1800, and 2400 ppm added CO2 using a continuous carbonation unit. After storage at 0 to 1 degree C, portions of milk at each CO2 concentration were heated to 40, 56, 72, and 80 degrees C, held at the desired temperature for 30 s (except 80 degrees C, holding 20 s) and cooled to 0 to 1 degree C. At each temperature, five pressures were applied: 69, 138, 207, 276, and 345 kPa. Pressure was controlled with a needle valve at the heat exchanger exit. Both the pressure gauge and pH probe were inline at the end of the holding section. Milk pH during heating depended on CO2 concentration, temperature, and pressure. During heating of milk without added CO2, pH decreased linearly as a function of increasing temperature but was independent of pressure. In general, the pH of milk with added CO2 decreased with increasing CO2 concentration and pressure. For milk with added CO2, at a fixed CO2 concentration, the effect of pressure on pH decrease was greater at a higher temperature. At a fixed temperature, the effect of pressure on pH decrease was greater for milk with a higher CO2 concentration. Thermal death of bacteria during pasteurization of milk without added CO2 is probably due not only to temperature but also to the decrease in pH that occurs during the process. Increasing milk CO2 concentration and pressure decreases the milk pH even further during heating and may further enhance the microbial killing power of pasteurization.

  16. Stability of a NDIR analyser for CO2 at atmospheric concentration.

    Science.gov (United States)

    Sega, Michela; Amico Di Meane, Elena; Plassa, Margherita

    2002-09-01

    Carbon dioxide monitoring is significant in the environmental field since this gas plays an important role in the greenhouse effect. In order to determine CO2 concentration and to develop simulation models, it is necessary to carry out measurements which are accurate and comparable in time and space, i.e. SI-traceable. Non-dispersive infrared (NDIR) analysers are employed for CO2 measurements, as they are precise and stable. In order to achieve traceability, such instruments have to be characterized and calibrated. At the Istituto di Metrologia "G. Colonnetti"--CNR, a procedure for calibrating NDIR analysers for CO2 at atmospheric level was developed, which enables to calculate a correction for the analyser output. In addition, a complete uncertainty analysis was carried out and a correct traceability chain was established. The goal of the present work is the study of the stability of a NDIR analyser by repeating calibrations during three years and comparing the correction curves obtained to identify a proper re-calibration interval for such analysers. The investigated instrument has good repeatability and reproducibility, hence satisfactory stability during time, as shown by the short-term and long-term compatibility of calibration curves.

  17. Mineral composition of durum wheat grain and pasta under increasing atmospheric CO2 concentrations.

    Science.gov (United States)

    Beleggia, Romina; Fragasso, Mariagiovanna; Miglietta, Franco; Cattivelli, Luigi; Menga, Valeria; Nigro, Franca; Pecchioni, Nicola; Fares, Clara

    2018-03-01

    The concentrations of 10 minerals were investigated in the grain of 12 durum wheat genotypes grown under free air CO2 enrichment conditions, and in four of their derived pasta samples, using inductively coupled plasma mass spectrometry. Compared to ambient CO2 (400ppm; AMB), under elevated CO2 (570ppm; ELE), the micro-element and macro-element contents showed strong and significant decreases in the grain: Mn, -28.3%; Fe, -26.7%; Zn, -21.9%; Mg, -22.7%; Mo, -40.4%; K, -22.4%; and Ca, -19.5%. These variations defined the 12 genotypes as sensitive or non-sensitive to ELE. The pasta samples under AMB and ELE showed decreased mineral contents compared to the grain. Nevertheless, the contributions of the pasta to the recommended daily allowances remained relevant, also for the micro-elements under ELE conditions (range, from 18% of the recommended daily allowance for Zn, to 70% for Mn and Mo). Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Dual-Pump Coherent Anti-Stokes Raman Scattering Temperature and CO2 Concentration Measurements

    Science.gov (United States)

    Lucht, Robert P.; Velur-Natarajan, Viswanathan; Carter, Campbell D.; Grinstead, Keith D., Jr.; Gord, James R.; Danehy, Paul M.; Fiechtner, G. J.; Farrow, Roger L.

    2003-01-01

    Measurements of temperature and CO2 concentration using dual-pump coherent anti-Stokes Raman scattering, (CARS) are described. The measurements were performed in laboratory flames,in a room-temperature gas cell, and on an engine test stand at the U.S. Air Force Research Laboratory, Wright-Patterson Air Force Base. A modeless dye laser, a single-mode Nd:YAG laser, and an unintensified back-illuminated charge-coupled device digital camera were used for these measurements. The CARS measurements were performed on a single-laser-shot basis. The standard deviations of the temperatures and CO2 mole fractions determined from single-shot dual-pump CARS spectra in steady laminar propane/air flames were approximately 2 and 10% of the mean values of approximately 2000 K and 0.10, respectively. The precision and accuracy of single-shot temperature measurements obtained from the nitrogen part of the dual-pump CARS system were investigated in detail in near-adiabatic hydrogen/air/CO2 flames. The precision of the CARS temperature measurements was found to be comparable to the best results reported in the literature for conventional two-laser, single-pump CARS. The application of dual-pump CARS for single-shot measurements in a swirl-stabilized combustor fueled with JP-8 was also demonstrated.

  19. Optimization of the process of concentration of vitamin e from DDSO using supercritical CO2

    Directory of Open Access Journals (Sweden)

    M. F. Mendes

    2005-03-01

    Full Text Available The objective of this work was the scientific development of concentration of vitamin E from deodorizer distillate of soybean oil (DDSO using supercritical CO2. Vitamins and sterols rare produced synthetically, but recently the interest in their extraction from natural sources has increased. Therefore, the motivation behind this work was to concentrate the tocopherols from deodorizer distillate of soybean oil, thereby increasing the value of this by-product, rich in fatty acids, sterols, tocopherols and squalene. The experimental step and the simulation of the process were done in a semi-batch mode using supercritical carbon dioxide. The operational conditions studied were temperatures of 40, 60 and 80ºC and pressures from 90 to 350 bar. The best results for concentration factor and efficiency and pressures were achieved in a continuous process where the operational variables were optimized.

  20. Solvation of CO2 in water: effect of RuBP on CO2 concentration in bundle sheath of C4 plants.

    Science.gov (United States)

    Sadhukhan, Tumpa; Latif, Iqbal A; Datta, Sambhu N

    2014-07-24

    An understanding of the temperature-dependence of solubility of carbon dioxide (CO2) in water is important for many industrial processes. Voluminous work has been done by both quantum chemical methods and molecular dynamics (MD) simulations on the interaction between CO2 and water, but a quantitative evaluation of solubility remains elusive. In this work, we have approached the problem by considering quantum chemically calculated total energies and thermal energies, and incorporating the effects of mixing, hydrogen bonding, and phonon modes. An overall equation relating the calculated free energy and entropy of mixing with the gas-solution equilibrium constant has been derived. This equation has been iteratively solved to obtain the solubility as functions of temperature and dielectric constant. The calculated solubility versus temperature plot excellently matches the observed plot. Solubility has been shown to increase with dielectric constant, for example, by addition of electrolytes. We have also found that at the experimentally reported concentration of enzyme RuBP in bundle sheath cells of chloroplast in C4 green plants, the concentration of CO2 can effectively increase by as much as a factor of 7.1-38.5. This stands in agreement with the observed effective rise in concentration by as much as 10 times.

  1. Effects of CO2 fine bubble injection on reactive crystallization of dolomite from concentrated brine

    Science.gov (United States)

    Tsuchiya, Yuko; Wada, Yoshinari; Hiaki, Toshihiko; Onoe, Kaoru; Matsumoto, Masakazu

    2017-07-01

    In this study, we used the minute gas-liquid interfaces around CO2 fine bubbles as new reaction fields where the crystal nucleation proceeds dominantly and developed a crystallization technique to synthesize dolomite (CaMg(CO3)2) with the desired crystal quality. CaMg(CO3)2 has a crystal structure derived from calcite by ordered replacement of the Ca2+ in calcite by Mg2+. To improve the functionality of the crystal for better utilization of the CaMg(CO3)2, an effective method for an approach to a Mg/Ca ratio of 1.0 and downsizing is indispensable in the crystallization process. In the vicinity of the minute gas-liquid interfaces, the accumulation of Ca2+ and Mg2+ is caused by the negative electric charge on the fine bubbles surface; thus, CaMg(CO3)2 fine particles with a high Mg/Ca ratio can be expected to crystallize. At a reaction temperature (Tr) of 298 K and CO2 flow rate (FCO2) of 11.9 mmol/(L min), CO2 bubbles with an average bubble diameter (dbbl) of 40-2000 μm were continuously supplied to 300 mL of the concentrated brine coming from salt manufacture discharge and CaMg(CO3)2 crystallized within a reaction time of 120 min. Fine bubbles with dbbl of 40 μm were generated using a self-supporting bubble generator by increasing the impeller shear rate under reduced pressure. For comparison, the bubbles with dbbl of 300 or 2000 μm were obtained using a dispersing-type generator. Moreover, FCO2 and Tr were varied as operating parameters during the reactive crystallization supplying CO2 fine bubbles. Consequently, CO2 fine bubble injection is effective for the high-yield crystallization of CaMg(CO3)2 with a Mg/Ca ratio of 1.0 and downsizing of CaMg(CO3)2 particles owing to the acceleration of crystal nucleation caused by the local increase in the supersaturation at the minute gas-liquid interfaces.

  2. Stomatal and pavement cell density linked to leaf internal CO2 concentration.

    Science.gov (United States)

    Santrůček, Jiří; Vráblová, Martina; Simková, Marie; Hronková, Marie; Drtinová, Martina; Květoň, Jiří; Vrábl, Daniel; Kubásek, Jiří; Macková, Jana; Wiesnerová, Dana; Neuwithová, Jitka; Schreiber, Lukas

    2014-08-01

    Stomatal density (SD) generally decreases with rising atmospheric CO2 concentration, Ca. However, SD is also affected by light, air humidity and drought, all under systemic signalling from older leaves. This makes our understanding of how Ca controls SD incomplete. This study tested the hypotheses that SD is affected by the internal CO2 concentration of the leaf, Ci, rather than Ca, and that cotyledons, as the first plant assimilation organs, lack the systemic signal. Sunflower (Helianthus annuus), beech (Fagus sylvatica), arabidopsis (Arabidopsis thaliana) and garden cress (Lepidium sativum) were grown under contrasting environmental conditions that affected Ci while Ca was kept constant. The SD, pavement cell density (PCD) and stomatal index (SI) responses to Ci in cotyledons and the first leaves of garden cress were compared. (13)C abundance (δ(13)C) in leaf dry matter was used to estimate the effective Ci during leaf development. The SD was estimated from leaf imprints. SD correlated negatively with Ci in leaves of all four species and under three different treatments (irradiance, abscisic acid and osmotic stress). PCD in arabidopsis and garden cress responded similarly, so that SI was largely unaffected. However, SD and PCD of cotyledons were insensitive to Ci, indicating an essential role for systemic signalling. It is proposed that Ci or a Ci-linked factor plays an important role in modulating SD and PCD during epidermis development and leaf expansion. The absence of a Ci-SD relationship in the cotyledons of garden cress indicates the key role of lower-insertion CO2 assimilation organs in signal perception and its long-distance transport. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Armazenamento refrigerado de morango submetido a altas concentrações de CO2 Cold storage of strawberries under high CO2 concentrations

    Directory of Open Access Journals (Sweden)

    Luis C Cunha Junior

    2012-12-01

    strawberries. However, fruits and vegetables are not currently handled under cold chain in Brazil and, when it happens, it used to be at 10 to 15ºC. The goal of this work was to evaluate the quality and the shelf life of 'Oso Grande' strawberry at 10ºC associated to high carbon dioxide concentrations. Strawberries were randomized, chilled and stored at 10ºC in hermetic mini-chambers to apply the CO2 concentrations (0.03, 10, 20, 40 and 80% plus 20% O2. Strawberries were analyzed every two days while they were proper to consumption. The shelf life for strawberries at 20 and 40% CO2 was 8 days, while those at 0.03% CO2 lasted only two days. Strawberries at 80% CO2 maintained good appearance for 6 days, but they were considered unsuitable for consumption due to high levels of acetaldehyde (40.92 µg g-1 and ethanol (1,053 µg g-1 that gave evidence of fermentation process. The weight loss was less than 2% showing how efficient was the method used to control the relative humidity during the storage. Strawberries at 0.03 and 80% CO2 levels showed higher firmness loss. Those fruits lost 40% of the initial firmness. Strawberries at 20 and 40% CO2 lost only 28% of initial firmness. Despite of the statistical effect of the treatments in the external color it was not visually perceptible. Strawberries stored at 10ºC and 40% CO2 plus 20% O2 kept the marketable quality during 8 days.

  4. Changes in the chloroplastic CO2 concentration explain much of the observed Kok effect: a model.

    Science.gov (United States)

    Farquhar, Graham D; Busch, Florian A

    2017-04-01

    Mitochondrial respiration often appears to be inhibited in the light when compared with measurements in the dark. This inhibition is inferred from the response of the net CO2 assimilation rate (A) to absorbed irradiance (I), changing slope around the light compensation point (Ic ). We suggest a model that provides a plausible mechanistic explanation of this 'Kok effect'. The model uses the mathematical description of photosynthesis developed by Farquhar, von Caemmerer and Berry; it involves no inhibition of respiration rate in the light. We also describe a fitting technique for quantifying the Kok effect at low I. Changes in the chloroplastic CO2 partial pressure (Cc ) can explain curvature of A vs I, its diminution in C4 plants and at low oxygen concentrations or high carbon dioxide concentrations in C3 plants, and effects of dark respiration rate and of temperature. It also explains the apparent inhibition of respiration in the light as inferred by the Laisk approach. While there are probably other sources of curvature in A vs I, variation in Cc can largely explain the curvature at low irradiance, and suggests that interpretation of day respiration compared with dark respiration of leaves on the basis of the Kok effect needs reassessment. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  5. [Effects of atmospheric CO2 concentration enhancement and nitrogen application rate on wheat grain yield and quality].

    Science.gov (United States)

    Cui, Hao; Shi, Zu-liang; Cai, Jian; Jiang, Dong; Cao, Wei-xing; Dai, Ting-bo

    2011-04-01

    FACE platform was applied to study the effects of elevated atmospheric CO2 concentration on wheat grain yield and quality under two nitrogen (N) application rates. Elevated atmospheric CO2 concentration and applying N increased the grain yield, spike number, grain number per spike, and biomass significantly, but elevated CO2 concentration had no significant effects on harvest index (HI). Under elevated CO2 concentration, there was a significant decrease in the protein, gliadin, gluteinin, and glutein contents of the grain and the sedimentation value of the flour, and a significant increase in the starch and its components contents of the grain; under N application, an inverse was observed. The dough stability time and the dough viscosity characteristics, such as peak viscosity, final viscosity, and setback value, increased significantly under elevated CO2 concentration and high N application rate. The interaction of atmospheric CO2 concentration and N application rate had significantly positive effects on wheat grain yield and biomass, but less effect on grain quality. Therefore, with elevated atmospheric CO2 concentration in the future, maintaining a higher N application level would benefit wheat grain yield and paste characteristics, and mitigate the decline of grain quality.

  6. Effect of Fe ion concentration on fatigue life of carbon steel in aqueous CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion fatigue behaviour of steel armours used in the flexible pipes, in aqueous solutions initially containing different concentrations of Fe2+, was investigated by four-point bending testing under saturated 1 bar CO2 condition. Corrosion fatigue results were supported with ex...... situ measurements of Fe2+ and pH. Characterisation of the corrosion scales and crack formations was performed using microscopic and diffraction techniques. Fatigue results showed two times better fatigue life, at the stress ranges of 250 MPa, for samples tested in solutions containing the concentration...... of Fe2+ marginally above the solubility limit of FeCO3 compared to the samples tested in highly supersaturated solution of Fe2+. Results revealed that the impact of the alternating stresses on the corrosion behaviour of samples reduces with lowering the applied stresses. At the stress range of 100 MPa...

  7. Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla

    Science.gov (United States)

    Cha, Sangsub; Chae, Hee-Myung; Lee, Sang-Hoon; Shim, Jae-Kuk

    2017-01-01

    The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition. PMID:28182638

  8. Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla.

    Science.gov (United States)

    Cha, Sangsub; Chae, Hee-Myung; Lee, Sang-Hoon; Shim, Jae-Kuk

    2017-01-01

    The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition.

  9. Leaf photosynthetic and morphological responses to elevated CO2 concentration and altered fruit number in the semi-closed greenhouse

    NARCIS (Netherlands)

    Qian, T.; Dieleman, J.A.; Elings, A.; Marcelis, L.F.M.

    2012-01-01

    Semi-closed greenhouses have been developed to reduce the energy consumption in horticulture. In these greenhouses, CO2 concentration is higher than in the conventional modern greenhouses due to the reduction of window ventilation. Photosynthetic and morphological acclimation to elevated CO2 has

  10. Modelling the concentration of atmospheric CO2 during the Younger Dryas climate event

    Science.gov (United States)

    Marchal, O.; Stocker, T. F.; Joos, F.; Indermühle, A.; Blunier, T.; Tschumi, J.

    The Younger Dryas (YD, dated between 12.7-11.6 ky BP in the GRIP ice core, Central Greenland) is a distinct cold period in the North Atlantic region during the last deglaciation. A popular, but controversial hypothesis to explain the cooling is a reduction of the Atlantic thermohaline circulation (THC) and associated northward heat flux as triggered by glacial meltwater. Recently, a CH4-based synchronization of GRIP δ18O and Byrd CO2 records (West Antarctica) indicated that the concentration of atmospheric CO2 (COatm2) rose steadily during the YD, suggesting a minor influence of the THC on COatm2 at that time. Here we show that the COatm2 change in a zonally averaged, circulation-biogeochemistry ocean model when THC is collapsed by freshwater flux anomaly is consistent with the Byrd record. Cooling in the North Atlantic has a small effect on COatm2 in this model, because it is spatially limited and compensated by far-field changes such as a warming in the Southern Ocean. The modelled Southern Ocean warming is in agreement with the anti-phase evolution of isotopic temperature records from GRIP (Northern Hemisphere) and from Byrd and Vostok (East Antarctica) during the YD. δ13C depletion and PO4 enrichment are predicted at depth in the North Atlantic, but not in the Southern Ocean. This could explain a part of the controversy about the intensity of the THC during the YD. Potential weaknesses in our interpretation of the Byrd CO2 record in terms of THC changes are discussed.

  11. Transcriptome response to elevated atmospheric CO2 concentration in the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae).

    Science.gov (United States)

    Wu, Wenjing; Li, Zhiqiang; Zhang, Shijun; Ke, Yunling; Hou, Yahui

    2016-01-01

    Carbon dioxide (CO2) is a pervasive chemical stimulus that plays a critical role in insect life, eliciting behavioral and physiological responses across different species. High CO2 concentration is a major feature of termite nests, which may be used as a cue for locating their nests. Termites also survive under an elevated CO2 concentration. However, the mechanism by which elevated CO2 concentration influences gene expression in termites is poorly understood. To gain a better understanding of the molecular basis involved in the adaptation to CO2 concentration, a transcriptome of Coptotermes formosanus Shiraki was constructed to assemble the reference genes, followed by comparative transcriptomic analyses across different CO2 concentration (0.04%, 0.4%, 4% and 40%) treatments. (1) Based on a high throughput sequencing platform, we obtained approximately 20 GB of clean data and revealed 189,421 unigenes, with a mean length and an N50 length of 629 bp and 974 bp, respectively. (2) The transcriptomic response of C. formosanus to elevated CO2 levels presented discontinuous changes. Comparative analysis of the transcriptomes revealed 2,936 genes regulated among 0.04%, 0.4%, 4% and 40% CO2 concentration treatments, 909 genes derived from termites and 2,027 from gut symbionts. Genes derived from termites appears selectively activated under 4% CO2 level. In 40% CO2 level, most of the down-regulated genes were derived from symbionts. (3) Through similarity searches to data from other species, a number of protein sequences putatively involved in chemosensory reception were identified and characterized in C. formosanus, including odorant receptors, gustatory receptors, ionotropic receptors, odorant binding proteins, and chemosensory proteins. We found that most genes associated with carbohydrate metabolism, energy metabolism, and genetic information processing were regulated under different CO2 concentrations. Results suggested that termites adapt to ∼4% CO2 level and their

  12. [Effect of elevated CO2 concentration on photosynthesis and antioxidative enzyme activities of wheat plant grown under drought condition].

    Science.gov (United States)

    Chen, X; Wu, D; Wang, G; Ren, H

    2000-12-01

    The photosynthesis and antioxidative enzyme activities of wheat plants grown in two open-top chambers with CO2 concentrations of 350 mumol.mol-1 and 700 mumol.mol-1 were examined under drought stress. The result showed that elevated CO2 concentration obviously enhanced the photosynthesis, stomatal resistance and water use efficiency, but decreased the transpiration of wheat. Doubled CO2 concentration significantly increased the activities of CAT, POD and SOD, which enhanced the abilities of antioxidative defence and drought tolerance.

  13. [Near surface CO2 concentration and its quantitative relationship with character of underlying surface in Shanghai City, China].

    Science.gov (United States)

    Pan, Chen; Zhu, Xi-yang; Jia, Wen-xiao; Yang, Fang; Liu, Ming; Xiang, Wei-ning

    2015-07-01

    Land use change and fossil fuel combustion due to urbanization have a significant effect on global carbon cycle and climate change. It's important to have an explicit understanding of the spatial distribution of CO2 to recognize and control GHG emission, which is helpful to reduce human-induced contribution to global climate change. The study area of this project was set in the city of Shanghai with intensive human activity and rapid urbanization. The monitoring of near surface CO2 concentration along 3 transects was conducted across an urban-rural gradient by means of near infrared gas analyzer Li-840A in spring, 2014. Remote sensing data were also used to derive underlying surface information. Further quantitative analysis of the mechanism of CO2 concentration's response to the characteristics of underlying surface was presented in this paper. The results showed that the average near surface CO2 concentration was (443.4±22.0) µmol . mol-1. CO2 concentration in city center was in average 12.5% (52.5 µLmol . mol-1) higher than that in the suburban area. Also, CO2 concentration showed a significant spatial differentiation, with the highest CO2 concentration in the northwest, the second highest in the southwest, and the lowest in the southeast, which was in accordance with the urbanization level of the underlying surface. The results revealed that the vegetation coverage rate (CVeg) was an important indicator to describe near surface CO2 concentration with a negative correlation, and the impervious surface area coverage rate (CISA) had lower explanatory power with a positive correlation. The study also found that the determination coefficient (R2) between CO2 concentration (CCO2) and CISA or CVeg achieved its highest value when the buffer distance was 5 km, and their quantitative relationships be described by a stepwise regression equation: CCO2=0.32CISA-0.89CVeg+445.13 (R2 =0.66, P<0.01).

  14. Bias assessment of lower and middle tropospheric CO2 concentrations of GOSAT/TANSO-FTS TIR version 1 product

    Science.gov (United States)

    Saitoh, Naoko; Kimoto, Shuhei; Sugimura, Ryo; Imasu, Ryoichi; Shiomi, Kei; Kuze, Akihiko; Niwa, Yosuke; Machida, Toshinobu; Sawa, Yousuke; Matsueda, Hidekazu

    2017-10-01

    CO2 observations in the free troposphere can be useful for constraining CO2 source and sink estimates at the surface since they represent CO2 concentrations away from point source emissions. The thermal infrared (TIR) band of the Thermal and Near Infrared Sensor for Carbon Observation (TANSO) Fourier transform spectrometer (FTS) on board the Greenhouse Gases Observing Satellite (GOSAT) has been observing global CO2 concentrations in the free troposphere for about 8 years and thus could provide a dataset with which to evaluate the vertical transport of CO2 from the surface to the upper atmosphere. This study evaluated biases in the TIR version 1 (V1) CO2 product in the lower troposphere (LT) and the middle troposphere (MT) (736-287 hPa), on the basis of comparisons with CO2 profiles obtained over airports using Continuous CO2 Measuring Equipment (CME) in the Comprehensive Observation Network for Trace gases by AIrLiner (CONTRAIL) project. Bias-correction values are presented for TIR CO2 data for each pressure layer in the LT and MT regions during each season and in each latitude band: 40-20° S, 20° S-20° N, 20-40° N, and 40-60° N. TIR V1 CO2 data had consistent negative biases of 1-1.5 % compared with CME CO2 data in the LT and MT regions, with the largest negative biases at 541-398 hPa, partly due to the use of 10 µm CO2 absorption band in conjunction with 15 and 9 µm absorption bands in the V1 retrieval algorithm. Global comparisons between TIR CO2 data to which the bias-correction values were applied and CO2 data simulated by a transport model based on the Nonhydrostatic ICosahedral Atmospheric Model (NICAM-TM) confirmed the validity of the bias-correction values evaluated over airports in limited areas. In low latitudes in the upper MT region (398-287 hPa), however, TIR CO2 data in northern summer were overcorrected by these bias-correction values; this is because the bias-correction values were determined using comparisons mainly over airports in

  15. Bias assessment of lower and middle tropospheric CO2 concentrations of GOSAT/TANSO-FTS TIR version 1 product

    Directory of Open Access Journals (Sweden)

    N. Saitoh

    2017-10-01

    Full Text Available CO2 observations in the free troposphere can be useful for constraining CO2 source and sink estimates at the surface since they represent CO2 concentrations away from point source emissions. The thermal infrared (TIR band of the Thermal and Near Infrared Sensor for Carbon Observation (TANSO Fourier transform spectrometer (FTS on board the Greenhouse Gases Observing Satellite (GOSAT has been observing global CO2 concentrations in the free troposphere for about 8 years and thus could provide a dataset with which to evaluate the vertical transport of CO2 from the surface to the upper atmosphere. This study evaluated biases in the TIR version 1 (V1 CO2 product in the lower troposphere (LT and the middle troposphere (MT (736–287 hPa, on the basis of comparisons with CO2 profiles obtained over airports using Continuous CO2 Measuring Equipment (CME in the Comprehensive Observation Network for Trace gases by AIrLiner (CONTRAIL project. Bias-correction values are presented for TIR CO2 data for each pressure layer in the LT and MT regions during each season and in each latitude band: 40–20° S, 20° S–20° N, 20–40° N, and 40–60° N. TIR V1 CO2 data had consistent negative biases of 1–1.5 % compared with CME CO2 data in the LT and MT regions, with the largest negative biases at 541–398 hPa, partly due to the use of 10 µm CO2 absorption band in conjunction with 15 and 9 µm absorption bands in the V1 retrieval algorithm. Global comparisons between TIR CO2 data to which the bias-correction values were applied and CO2 data simulated by a transport model based on the Nonhydrostatic ICosahedral Atmospheric Model (NICAM-TM confirmed the validity of the bias-correction values evaluated over airports in limited areas. In low latitudes in the upper MT region (398–287 hPa, however, TIR CO2 data in northern summer were overcorrected by these bias-correction values; this is because the bias-correction values were determined

  16. A Spatial Interactome Reveals the Protein Organization of the Algal CO2-Concentrating Mechanism.

    Science.gov (United States)

    Mackinder, Luke C M; Chen, Chris; Leib, Ryan D; Patena, Weronika; Blum, Sean R; Rodman, Matthew; Ramundo, Silvia; Adams, Christopher M; Jonikas, Martin C

    2017-09-21

    Approximately one-third of global CO2 fixation is performed by eukaryotic algae. Nearly all algae enhance their carbon assimilation by operating a CO2-concentrating mechanism (CCM) built around an organelle called the pyrenoid, whose protein composition is largely unknown. Here, we developed tools in the model alga Chlamydomonas reinhardtii to determine the localizations of 135 candidate CCM proteins and physical interactors of 38 of these proteins. Our data reveal the identity of 89 pyrenoid proteins, including Rubisco-interacting proteins, photosystem I assembly factor candidates, and inorganic carbon flux components. We identify three previously undescribed protein layers of the pyrenoid: a plate-like layer, a mesh layer, and a punctate layer. We find that the carbonic anhydrase CAH6 is in the flagella, not in the stroma that surrounds the pyrenoid as in current models. These results provide an overview of proteins operating in the eukaryotic algal CCM, a key process that drives global carbon fixation. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Rubisco activity in Mediterranean species is regulated by the chloroplastic CO2 concentration under water stress

    Science.gov (United States)

    Galmés, Jeroni; Ribas-Carbó, Miquel; Medrano, Hipólito; Flexas, Jaume

    2011-01-01

    Water stress decreases the availability of the gaseous substrate for ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) by decreasing leaf conductance to CO2. In spite of limiting photosynthetic carbon assimilation, especially in those environments where drought is the predominant factor affecting plant growth and yield, the effects of water deprivation on the mechanisms that control Rubisco activity are unclear. In the present study, 11 Mediterranean species, representing different growth forms, were subject to increasing levels of drought stress, the most severe one followed by rewatering. The results confirmed species-specific patterns in the decrease in the initial activity and activation state of Rubisco as drought stress and leaf dehydration intensified. Nevertheless, all species followed roughly the same trend when Rubisco activity was related to stomatal conductance (gs) and chloroplastic CO2 concentration (Cc), suggesting that deactivation of Rubisco sites could be induced by low Cc, as a result of water stress. The threshold level of Cc that triggered Rubisco deactivation was dependent on leaf characteristics and was related to the maximum attained for each species under non-stressing conditions. Those species adapted to low Cc were more capable of maintaining active Rubisco as drought stress intensified. PMID:21115663

  18. Development of a low cost and low power consumption system for monitoring CO_{2} soil concentration in volcanic areas.

    Science.gov (United States)

    Awadallah Estévez, Shadia; Moure-García, David; Torres-González, Pedro; Acosta Sánchez, Leopoldo; Domínguez Cerdeña, Itahiza

    2017-04-01

    Volatiles dissolved in magma are released as gases when pressure or stress conditions change. H2O, CO2, SO2 and H2S are the most abundant gases involved in volcanic processes. Emission rates are related to changes in the volcanic activity. Therefore, in order to predict possible eruptive events, periodic measurements of CO2 concentrations from the soil should be carried out. In the last years, CO2 monitoring has been widespread for many reasons. A direct relationship between changes in volcanic activity and variations in concentration, diffuse flux and isotope ratios of this gas, have been observed prior to some eruptions or unrest processes. All these factors have pointed out the fact that CO2 emission data are crucial in volcanic monitoring programs. In addition, relevant instrumentation development has also taken place: improved accuracy, cost reduction and portability. Considering this, we propose a low cost and a low power consumption system for measuring CO2 concentration in the soil based on Arduino. Through a perforated pick-axe buried at a certain depth, gas samples are periodically taken with the aid of a piston. These samples are injected through a pneumatic circuit in the spectrometer, which measures the CO2 concentration. Simultaneously, the system records the following meteorological parameters: atmospheric pressure, precipitation, relative humidity and air and soil temperature. These parameters are used to correct their possible influence in the CO2 soil concentration. Data are locally stored (SD card) and transmitted via GPRS or WIFI to a data analysis center.

  19. Impact of elevated CO2 concentration on dynamics of leaf photosynthesis in Fagus sylvatica is modulated by sky conditions.

    Science.gov (United States)

    Urban, Otmar; Klem, Karel; Holišová, Petra; Šigut, Ladislav; Šprtová, Mirka; Teslová-Navrátilová, Petra; Zitová, Martina; Špunda, Vladimír; Marek, Michal V; Grace, John

    2014-02-01

    It has been suggested that atmospheric CO2 concentration and frequency of cloud cover will increase in future. It remains unclear, however, how elevated CO2 influences photosynthesis under complex clear versus cloudy sky conditions. Accordingly, diurnal changes in photosynthetic responses among beech trees grown at ambient (AC) and doubled (EC) CO2 concentrations were studied under contrasting sky conditions. EC stimulated the daily sum of fixed CO2 and light use efficiency under clear sky. Meanwhile, both these parameters were reduced under cloudy sky as compared with AC treatment. Reduction in photosynthesis rate under cloudy sky was particularly associated with EC-stimulated, xanthophyll-dependent thermal dissipation of absorbed light energy. Under clear sky, a pronounced afternoon depression of CO2 assimilation rate was found in sun-adapted leaves under EC compared with AC conditions. This was caused in particular by stomata closure mediated by vapour pressure deficit. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Reduction of CO 2 concentration in a zinc/air battery by absorption in a rotating packed bed

    Science.gov (United States)

    Cheng, Hsu-Hsiang; Tan, Chung-Sung

    The reduction of CO 2 concentration in a gas stream containing 500 ppm of CO 2 by a technique combining chemical absorption with Higee (high gravity) was investigated in this study. Using a 2.0 L aqueous amine-based solution to treat the feed gas with a flow rate which varied from 12.9 to 20.6 L min -1, piperazine (PZ) was found to be more effective than 2-(2-aminoethylamino) ethanol (AEEA) and monoethanolamine (MEA) for reducing the CO 2 concentration to a level below 20 ppm. The effects of temperature, rotating speed, amine solution flow rate, and gas flow rate on the removal efficiency of CO 2 were systematically examined. The results indicated that the proposed compact device could effectively reduce CO 2 to a level below 20 ppm, as required by a zinc/air battery, for a long period of time using PZ and its mixture with AEEA and MEA as the absorbents.

  1. Effects of elevated CO2 concentration on growth and water usage of tomato seedlings under different ammonium/nitrate ratios.

    Science.gov (United States)

    Li, Juan; Zhou, Jian-Min; Duan, Zeng-Qiang

    2007-01-01

    Increasing atmospheric CO2 concentration is generally expected to enhance photosynthesis and growth of agricultural C3 vegetable crops, and therefore results in an increase in crop yield. However, little is known about the combined effect of elevated CO2 and N species on plant growth and development. Two growth-chamber experiments were conducted to determine the effects of NH4+/NO3- ratio and elevated CO2 concentration on the physiological development and water use of tomato seedlings. Tomato was grown for 45 d in containers with nutrient solutions varying in NH4+/NO3- ratios and CO2 concentrations in growth chambers. Results showed that plant height, stem thickness, total dry weight, dry weight of the leaves, stems and roots, G value (total plant dry weight/seedling days), chlorophyll content, photosynthetic rate, leaf-level and whole plant-level water use efficiency and cumulative water consumption of tomato seedlings were increased with increasing proportion of NO3- in nutrient solutions in the elevated CO2 treatment. Plant biomass, plant height, stem thickness and photosynthetic rate were 67%, 22%, 24% and 55% higher at elevated CO2 concentration than at ambient CO2 concentration, depending on the values of NH4+/NO3- ratio. These results indicated that elevating CO2 concentration did not mitigate the adverse effects of 100% NH4(+)-N (in nutrient solution) on the tomato seedlings. At both CO2 levels, NH4+/NO3- ratios of nutrient solutions strongly influenced almost every measure of plant performance, and nitrate-fed plants attained a greater biomass production, as compared to ammonium-fed plants. These phenomena seem to be related to the coordinated regulation of photosynthetic rate and cumulative water consumption of tomato seedlings.

  2. Photosynthesis of C3 and C4 Species in Response to Increased CO2 Concentration and Drought Stress

    Directory of Open Access Journals (Sweden)

    HAMIM

    2005-12-01

    Full Text Available Photosynthetic gas exchange in response to increased carbon dioxide concentration ([CO2] and drought stress of two C3 (wheat and kale and two C4 species (Echinochloa crusgallii and Amaranthus caudatus were analysed. Plants were grown in controlled growth chambers with ambient (350 μmol mol−1 and doubled ambient [CO2]. Drought was given by withholding water until the plants severely wilted, whereas the control plants were watered daily. Even though stomatal conductance (Gs of C4 species either under ambient or double [CO2] was lower than those in C3, doubled [CO2] decreased Gs of all species under well watered conditions. As a result, the plants grown under doubled [CO2] transpired less water than those grown under ambient [CO2]. Photosynthesis (Pn of the C4 species was sustained during moderate drought when those of the C3 species decreased significantly. Doubled [CO2] increased photosynthesis of C3 but not of C4 species. Increased [CO2] was only able to delay Pn reduction of all species due to the drought, but not remove it completely. The positive effects of increased [CO2] during moderate drought and the disappearance of it under severe drought suggesting that metabolic effect may limit photosynthesis under severe drought.

  3. Photosynthesis of C3 and C4 Species in Response to Increased CO2 Concentration and Drought Stress

    Directory of Open Access Journals (Sweden)

    HAMIM

    2005-12-01

    Full Text Available Photosynthetic gas exchange in response to increased carbon dioxide concentration ([CO2] and drought stress of two C3 (wheat and kale and two C4 species (Echinochloa crusgallii and Amaranthus caudatus were analysed. Plants were grown in controlled growth chambers with ambient (350 mol mol-1 and doubled ambient [CO2]. Drought was given by withholding water until the plants severely wilted, whereas the control plants were watered daily. Even though stomatal conductance (Gs of C4 species either under ambient or double [CO2] was lower than those in C3, doubled [CO2] decreased Gs of all species under well watered conditions. As a result, the plants grown under doubled [CO2] transpired less water than those grown under ambient [CO2]. Photosynthesis (Pn of the C4 species was sustained during moderate drought when those of the C3 species decreased significantly. Doubled [CO2] increased photosynthesis of C3 but not of C4 species. Increased [CO2] was only able to delay Pn reduction of all species due to the drought, but not remove it completely. The positive effects of increased [CO2] during moderate drought and the disappearance of it under severe drought suggesting that metabolic effect may limit photosynthesis under severe drought.

  4. ACT-America: L2 In Situ Atmospheric CO2, CO, CH4, and O3 Concentrations, Eastern USA

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides atmospheric carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and ozone (O3) concentrations collected during airborne campaigns...

  5. CARVE: L2 Atmospheric CO2, CO and CH4 Concentrations, Harvard CRDS, Alaska, 2012-2014

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides atmospheric carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) concentrations from airborne campaigns over the Alaskan and Canadian...

  6. CARVE: L2 Merged Atmospheric CO2, CO, O3 and CH4 Concentrations, Alaska, 2012-2015

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides atmospheric carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), ozone (O3), and water vapor (H2O) concentrations from airborne...

  7. CARVE: L2 Atmospheric CO2, CO and CH4 Concentrations, NOAA CRDS, Alaska, 2012-2015

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides atmospheric carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and water vapor (H2O) concentrations from airborne campaigns over the...

  8. Biomass Energy for Transport and Electricity: Large scale utilization under low CO2 concentration scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Luckow, Patrick; Wise, Marshall A.; Dooley, James J.; Kim, Son H.

    2010-01-25

    This paper examines the potential role of large scale, dedicated commercial biomass energy systems under global climate policies designed to stabilize atmospheric concentrations of CO2 at 400ppm and 450ppm. We use an integrated assessment model of energy and agriculture systems to show that, given a climate policy in which terrestrial carbon is appropriately valued equally with carbon emitted from the energy system, biomass energy has the potential to be a major component of achieving these low concentration targets. The costs of processing and transporting biomass energy at much larger scales than current experience are also incorporated into the modeling. From the scenario results, 120-160 EJ/year of biomass energy is produced by midcentury and 200-250 EJ/year by the end of this century. In the first half of the century, much of this biomass is from agricultural and forest residues, but after 2050 dedicated cellulosic biomass crops become the dominant source. A key finding of this paper is the role that carbon dioxide capture and storage (CCS) technologies coupled with commercial biomass energy can play in meeting stringent emissions targets. Despite the higher technology costs of CCS, the resulting negative emissions used in combination with biomass are a very important tool in controlling the cost of meeting a target, offsetting the venting of CO2 from sectors of the energy system that may be more expensive to mitigate, such as oil use in transportation. The paper also discusses the role of cellulosic ethanol and Fischer-Tropsch biomass derived transportation fuels and shows that both technologies are important contributors to liquid fuels production, with unique costs and emissions characteristics. Through application of the GCAM integrated assessment model, it becomes clear that, given CCS availability, bioenergy will be used both in electricity and transportation.

  9. Relating Nimbus-7 37 GHz data to global land-surface evaporation, primary productivity and the atmospheric CO2 concentration

    Science.gov (United States)

    Choudhury, B. J.

    1988-01-01

    Global observations at 37 GHz by the Nimbus-7 SMMR are related to zonal variations of land surface evaporation and primary productivity, as well as to temporal variations of atmospheric CO2 concentration. The temporal variation of CO2 concentration and the zonal variations of evaporation and primary productivity are shown to be highly correlated with the satellite sensor data. The potential usefulness of the 37-GHz data for global biospheric and climate studies is noted.

  10. CO2 absorption/emission and aerodynamic effects of trees on the concentrations in a street canyon in Guangzhou, China.

    Science.gov (United States)

    Li, Jian-Feng; Zhan, Jie-Min; Li, Y S; Wai, Onyx W H

    2013-06-01

    In this paper, the effects of trees on CO2 concentrations in a street canyon in Guangzhou, China are examined by Computational Fluid Dynamics (CFD) simulations of the concentration distribution, taking into account both the CO2 absorption/emission and aerodynamic effects of trees. Simulation results show that, under a 2 m/s southerly prevailing wind condition, CO2 absorption by trees will reduce the CO2 concentration by around 2.5% in the daytime and at the same time the trees' resistance will increase the difference of CO2 concentrations in the street and at the inflow by 43%. As the traffic density increases to 50 vehicles/min, the effect of trees on the ambient CO2 concentration will change from positive to negative. At night, trees have a negative effect on the concentration in the street canyon mainly because of their resistance to airflow. When environmental wind changes, the effect of trees will be different. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Concentration and stable carbon isotopic composition of CO2 in cave air of Postojnska jama, Slovenia

    Directory of Open Access Journals (Sweden)

    Magda Mandic

    2013-09-01

    Full Text Available Partial pressure of CO2 (pCO2 and its isotopic composition (δ13CairCO2 were measured in Postojnska jama, Slovenia, at 10 locations inside the cave and outside the cave during a one-year period. At all interior locations the pCO2 was higher and δ13CairCO2 lower than in the outside atmosphere. Strong seasonal fluctuations in both parameters were observed at locations deeper in the cave, which are isolated from the cave air circulation. By using a binary mixing model of two sources of CO2, one of them being the atmospheric CO2, we show that the excess of CO2 in the cave air has a δ13C value of -23.3 ± 0.7 ‰, in reasonable agreement with the previously measured soil-CO2 δ13C values. The stable isotope data suggest that soil CO2 is brought to the cave by drip water.

  12. The Influence of Elevated CO2 Concentration on the Fitness Traits of Frankliniella occidentalis and Frankliniella intonsa (Thysanoptera: Thripidae).

    Science.gov (United States)

    ShuQi, He; Ying, Lin; Lei, Qian; ZhiHua, Li; Chao, Xi; Lu, Yang; FuRong, Gui

    2017-06-01

    Development and fecundity were investigated in an invasive alien thrips species, Frankliniella occidentalis (Pergande), and a related native species, Frankliniella intonsa (Trybom), under high CO2 concentration. Results show that the two thrips species reacted differently toward elevated CO2 concentration. Developmental duration decreased significantly (11.93%) in F. occidentalis at the CO2 concentration of 800 µl/liter; survival rate of all stages also significantly increased (e.g., survival rate of first instar increased 17.80%), adult longevity of both female and male extended (e.g., female increased 2.02 d on average), and both fecundity and daily eggs laid per female were higher at a CO2 concentration of 800 µl/liter than at 400 µl/liter. Developmental duration of F. intonsa decreased, insignificantly, at a CO2 concentration of 800 µl/liter. Unlike F. occidentalis, survival rate of F. intonsa declined considerably at higher CO2 concentration level (e.g., survival rate of first instar decreased 19.70%), adult longevity of both female and male curtailed (e.g., female reduced 3.82 d on average), and both fecundity and daily eggs laid per female were reduced to 24.86 and 0.83, respectively, indicating that there exist significant differences between the two CO2 levels. Results suggest that the population fitness of invasive thrips species might be enhanced with increase in CO2 concentration, and accordingly change the local thrips population composition with their invasion. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. CO32− concentration and pCO2 thresholds for calcification and dissolution on the Molokai reef flat, Hawaii

    Directory of Open Access Journals (Sweden)

    K. K. Yates

    2006-01-01

    Full Text Available The severity of the impact of elevated atmospheric pCO2 to coral reef ecosystems depends, in part, on how seawater pCO2 affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO2 and CO32− to in situ rates of reef calcification in natural settings to accurately predict the impact of elevated atmospheric pCO2 on calcification and dissolution processes. Rates of net calcification and dissolution, CO32− concentrations, and pCO2 were measured, in situ, on patch reefs, bare sand, and coral rubble on the Molokai reef flat in Hawaii. Rates of calcification ranged from 0.03 to 2.30 mmol CaCO3 m−2 h−1 and dissolution ranged from –0.05 to –3.3 mmol CaCO3 m−2 h−1. Calcification and dissolution varied diurnally with net calcification primarily occurring during the day and net dissolution occurring at night. These data were used to calculate threshold values for pCO2 and CO32− at which rates of calcification and dissolution are equivalent. Results indicate that calcification and dissolution are linearly correlated with both CO32− and pCO2. Threshold pCO2 and CO32− values for individual substrate types showed considerable variation. The average pCO2 threshold value for all substrate types was 654±195 μatm and ranged from 467 to 1003 μatm. The average CO32− threshold value was 152±24 μmol kg−1, ranging from 113 to 184 μmol kg−1. Ambient seawater measurements of pCO2 and CO32− indicate that CO32− and pCO2 threshold values for all substrate types were both exceeded, simultaneously, 13% of the time at present day atmospheric pCO2 concentrations. It is predicted that atmospheric pCO2 will exceed the average pCO2 threshold value for calcification and dissolution on the Molokai reef flat by the year 2100.

  14. A reduced order model to analytically infer atmospheric CO2 concentration from stomatal and climate data

    Science.gov (United States)

    Konrad, Wilfried; Katul, Gabriel; Roth-Nebelsick, Anita; Grein, Michaela

    2017-06-01

    To address questions related to the acceleration or deceleration of the global hydrological cycle or links between the carbon and water cycles over land, reliable data for past climatic conditions based on proxies are required. In particular, the reconstruction of palaeoatmospheric CO2 content (Ca) is needed to assist the separation of natural from anthropogenic Ca variability and to explore phase relations between Ca and air temperature Ta time series. Both Ta and Ca are needed to fingerprint anthropogenic signatures in vapor pressure deficit, a major driver used to explain acceleration or deceleration phases in the global hydrological cycle. Current approaches to Ca reconstruction rely on a robust inverse correlation between measured stomatal density in leaves (ν) of many plant taxa and Ca. There are two methods that exploit this correlation: The first uses calibration curves obtained from extant species assumed to represent the fossil taxa, thereby restricting the suitable taxa to those existing today. The second is a hybrid eco-hydrological/physiological approach that determines Ca with the aid of systems of equations based on quasi-instantaneous leaf-gas exchange theories and fossil stomatal data collected along with other measured leaf anatomical traits and parameters. In this contribution, a reduced order model (ROM) is proposed that derives Ca from a single equation incorporating the aforementioned stomatal data, basic climate (e.g. temperature), estimated biochemical parameters of assimilation and isotope data. The usage of the ROM is then illustrated by applying it to isotopic and anatomical measurements from three extant species. The ROM derivation is based on a balance between the biochemical demand and atmospheric supply of CO2 that leads to an explicit expression linking stomatal conductance to internal CO2 concentration (Ci) and Ca. The resulting expression of stomatal conductance from the carbon economy of the leaf is then equated to another

  15. [Measurements of CO2 concentration at high temperature and pressure environments using tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Cai, Ting-Dong; Gao, Guang-Zhen; Wang, Min-Rui; Wang, Gui-Shi; Gao, Xiao-Ming

    2014-07-01

    The present research was planned to develop a method for species concentration measurements under high temperature and pressure environments. The characteristics of CO2 spectrum at high temperature and pressure were studied at first. Based on the research above, tunable diode-laser absorption of CO2 near 2.0 microm incorporating fixed-wavelength modulation spectroscopy with second-harmonic detection was used to provide a method for sensitive and accurate measurements of gas temperature and CO2 concentration at high temperature and pressure. Measurements were performed in a well-controlled high temperature and pressure static cell. The results show that the average error of the CO2 concentration measurements at 5 atm, 500 K and 10 atm, 1000 K is 4. 49%. All measurements show the accuracy and potential utility of the method for high temperature and pressure diagnostics.

  16. Effects of different CO2 concentration on growth and photosynthetic of rain tree plants (Albizia saman jacq.Merr)

    Science.gov (United States)

    Fathurrahman, F.; Nizam, M. S.; Wan Juliana, W. A.; Doni, Febri; NorLailatul, W. M.; Che Radziah, C. M. Z.

    2016-11-01

    A preliminary study was conducted to determine the effect of elevated carbon dioxide (CO2) in rain tree growth under controllable growth chamber. The tolerance towards CO2 absorption in the photosynthesis process for the growth of tree rain is still unknown. In this study, rain tree seedlings were incubated for three months in a growth chamber with three different CO2 concentration treatment: GC1 (300 ppm), GC2 (600 ppm) and GC3 (900 ppm) at similar condition of temperature (28°C), humidity (60%) and lighting (1200 lux). The results showed that increased CO2 significantly increase the growth rate and chlorophyll content in rain tree. The results of this study add to the further understanding of how the improvement of the growth and physiological characteristics of rain tree was affected by CO2 enrichment treatment. This research can for used for global warming mitigation in the future.

  17. Airborne Measurements of CO2 Column Concentration and Range Using a Pulsed Direct-Detection IPDA Lidar

    Science.gov (United States)

    Abshire, James B.; Ramanathan, Anand; Riris, Haris; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Weaver, Clark J.; Browell, Edward V.

    2013-01-01

    We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The lidar measures the atmospheric backscatter profiles and samples the shape of the 1,572.33 nm CO2 absorption line. We participated in the ASCENDS science flights on the NASA DC-8 aircraft during August 2011 and report here lidar measurements made on four flights over a variety of surface and cloud conditions near the US. These included over a stratus cloud deck over the Pacific Ocean, to a dry lake bed surrounded by mountains in Nevada, to a desert area with a coal-fired power plant, and from the Rocky Mountains to Iowa, with segments with both cumulus and cirrus clouds. Most flights were to altitudes >12 km and had 5-6 altitude steps. Analyses show the retrievals of lidar range, CO2 column absorption, and CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds, between cumulus clouds, and to stratus cloud tops. The retrievals shows the decrease in column CO2 due to growing vegetation when flying over Iowa cropland as well as a sudden increase in CO2 concentration near a coal-fired power plant. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption lineshape (averaged for 50 s) matched the predicted shapes to better than 1% RMS error. For 10 s averaging, the scatter in the retrievals was typically 2-3 ppm and was limited by the received signal photon count. Retrievals were made using atmospheric parameters from both an atmospheric model and from in situ temperature and pressure from the aircraft. The retrievals had no free parameters and did not use empirical adjustments, and >70% of the measurements passed screening and were used in analysis. The differences between the lidar-measured retrievals and in situ measured average CO2 column concentrations were 6 km.

  18. [Effects of drought stress, high temperature and elevated CO2 concentration on the growth of winter wheat].

    Science.gov (United States)

    Si, Fu-Yan; Qiao, Yun-Zhou; Jiang, Jing-Wei; Dong, Bao-Di; Shi, Chang-Hai; Liu, Meng-Yu

    2014-09-01

    The impacts of climate change on the grain yield, photosynthesis, and water conditions of winter wheat were assessed based on an experiment, in which wheat plants were subjected to ambient and elevated CO2 concentrations, ambient and elevated temperatures, and low and high water conditions independently and in combination. The CO2 enrichment alone had no effect on the photosynthesis of winter wheat, whereas higher temperature and drought significantly decreased the photosynthetic rate. Water conditions in flag leaves were not significantly changed at the elevated CO2 concentration or elevated temperature. However, drought stress decreased the relative water content in flag leaves, and the combination of elevated temperature and drought reduced the water potential in flag leaves. The combination of elevated CO2 concentration, elevated temperature, and drought significantly reduced the photosynthetic rate and water conditions, and led to a 41.4% decrease in grain yield. The elevated CO2 concentration alone increased the grain yield by 21.2%, whereas the elevated temperature decreased the grain yield by 12.3%. The grain yield was not affected by the combination of elevated CO2 concentration and temperature, but the grain yield was significantly decreased by the drought stress if combined with any of the climate scenarios applied in this study. These findings suggested that maintaining high soil water content might be a vital means of reducing the potential harm caused by the climate change.

  19. The polar ocean and glacial cycles in atmospheric CO(2) concentration.

    Science.gov (United States)

    Sigman, Daniel M; Hain, Mathis P; Haug, Gerald H

    2010-07-01

    Global climate and the atmospheric partial pressure of carbon dioxide () are correlated over recent glacial cycles, with lower during ice ages, but the causes of the changes are unknown. The modern Southern Ocean releases deeply sequestered CO(2) to the atmosphere. Growing evidence suggests that the Southern Ocean CO(2) 'leak' was stemmed during ice ages, increasing ocean CO(2) storage. Such a change would also have made the global ocean more alkaline, driving additional ocean CO(2) uptake. This explanation for lower ice-age , if correct, has much to teach us about the controls on current ocean processes.

  20. Surface water CO2 concentration influences phytoplankton production but not community composition across boreal lakes.

    Science.gov (United States)

    Vogt, Richard J; St-Gelais, Nicolas F; Bogard, Matthew J; Beisner, Beatrix E; Del Giorgio, Paul A

    2017-11-01

    Recent experimental evidence suggests that changes in the partial pressure of CO2 (pCO2 ), in concert with nutrient fertilisation, may result in increased primary production and shifted phytoplankton community composition that favours species lacking adaptations to low CO2 environments. It is not clear whether these results apply in ambient freshwaters, which are already often supersaturated in CO2 , and where phytoplankton structure and activity are under complex control of diverse local and regional factors. Here, we use a large-scale comparative study of 69 boreal lakes to explore the influence of existing CO2 gradients (c. 50-2300 μatm) on phytoplankton community composition and biomass production. While community composition did not respond to pCO2 gradients, gross primary production was enhanced, but only in lakes already supersaturated in CO2 , demonstrating that environmental context is key in determining pCO2 -phytoplankton interactions. We further argue that increased atmospheric CO2 is unlikely to influence phytoplanktonic composition and production in northern lakes. © 2017 John Wiley & Sons Ltd/CNRS.

  1. Toxic effects of anthraquinone and phenanthrenequinone upon Scenedesmus strains (green algae) at low and elevated concentration of CO2.

    Science.gov (United States)

    Tukaj, Zbigniew; Aksmann, Anna

    2007-01-01

    Short-term (24h) experiments were performed to examine the effect of anthraquinone (ANTQ) and phenanthrenequinone (PHEQ) on two Scenedesmus armatus strains (B1-76 and 276-4d) grown in a batch culture system aerated with CO2 at a low (0.1%) or elevated (2%) concentration. ANTQ at concentrations within the range of 0.156-1.250 mg dm-3 inhibited the growth of B1-76 population in a concentration-dependent manner, and calculated EC50 for low-CO2 cells was 0.56 mg dm-3. The toxic effect of ANTQ on this strain was more pronounced in high-CO2 cells, where not only growth but also photosynthesis, respiration and SOD activity were significantly inhibited. In contrast, except for SOD activity, no ANTQ effects on strain 276-4d were found. PHEQ at concentrations within the range of 0.063-0.125 mg dm-3 inhibited the growth of B1-76 population in a concentration-dependent manner. The value of EC50 for low-CO2 B1-76 cells was 0.10 mg dm-3. PHEQ inhibited the growth of both strains regardless of CO2 concentration. In B1-76 cells affected by PHEQ, inhibition of photosynthesis was independent of the CO2 level, whereas the SOD activity was much higher in cultures aerated with 2% than with 0.1% CO2. Higher toxicity of PHEQ to strain 276-4d grown at 2% CO2 was accompanied by strong inhibition of photosynthesis, while in low-CO2 cells this process was slightly stimulated. The SOD activity in both low- and high-CO2 cells of strain 276-4d treated with PHEQ was 2-3 times higher compared with the controls. The pattern of SOD isoforms (PAGE analysis) obtained from cells exposed to ANTQ or PHEQ did not change compared with the controls, but the location of the SOD isoforms bands on gel was affected by the concentration of CO2. The results suggest that the strain-specific toxicity of ANTQ and PHEQ may result from oxidative stress. In addition, carbon dioxide appears to play an important role in the toxicity of quinones to algae.

  2. Effect of SO2 concentration as an impurity on carbon steel corrosion under subcritical CO2 environment

    Science.gov (United States)

    Mahlobo, MGR; Premlall, K.; Olubambi, PA

    2017-12-01

    Carbon dioxide (CO2) is considered to be easier to transport over moderate distances when turned into supercritical state (dense phase) than at any other state. Because of this reason, the transportation of CO2 during carbon capture and storage requires CO2 to be at its supercritical state. CO2 temperature profile from different regions causes CO2 to deviate between supercritical and subcritical state (gas/liquid phase). In this study the influence of sulphur dioxide (SO2) on the corrosion of carbon steel was evaluated under different SO2 concentrations (0.5, 1.5 and 5%) in combination with subcritical CO2. Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Energy-Dispersive X-ray Spectroscopy (EDS) were used to characterize the CO2 corrosion product layer formed on the carbon steel surface. The weight loss results showed that corrosion rate increased with SO2 concentration with corrosion rate up to 7.45 mm/year while at 0% SO2 the corrosion rate was 0.067 mm/year.

  3. Effects of CO2 and O2 concentrations and light intensity on growth of microalgae (Euglena gracilis) in CELSS.

    Science.gov (United States)

    Kitaya, Y; Kibe, S; Oguchi, M; Tanaka, H; Miyatake, K; Nakano, Y

    1998-01-01

    Green microalgae are likely to play an important role in bioregenerative systems for producing food and converting CO2 to O2 in a controlled ecological life support system (CELSS). In the present study, a method for evaluating the effects of environmental variables on the multiplication rate of microalgal cells was developed to determine the optimum culture condition for a microalgal culture system that can function effectively in the CELSS. The microalga, Euglena gracilis, was cultured in water droplets (3 microliters in liquid volume each) in a vessel (25 ml in air volume) in which the CO2 and O2 concentrations were controlled. The number of Euglena cells cultured at CO2 concentrations ranging from 2% to 6%, O2 concentrations ranging from 5% to 20%, and PPF levels ranging from 50 to 100 micromoles m-2 s-1 was monitored by using a video camera and a microscope. The multiplication rate of cells was highest and the cell number increased by 8.3 times during 48 h under a condition of 4% CO2, 21% O2 and 100 micromoles m-2 s-1 PPF. The multiplication rate of the cells was highest at 4% CO2, followed by 6% and 2% CO2, and it decreased with decreasing O2 concentration and decreasing PPF.

  4. Temporal variability and spatial dynamics of CO2 and CH4 concentrations and fluxes in the Zambezi River system

    Science.gov (United States)

    Teodoru, Cristian; Borges, Alberto; Bouillon, Steven; Nyoni, Frank; Nyambe, Imasiku

    2014-05-01

    Spanning over 2900 km in length and with a catchment of approximately 1.4 million km2, the Zambezi River is the fourth largest river in Africa and the largest flowing into the Indian Ocean from the African continent. Yet, there is surprisingly little or no information on carbon (C) cycling in this large river system. As part of a broader study on the riverine biogeochemistry in the Zambezi River basin, we present here mainstream dissolved CO2 and CH4 data collected during 2012 and 2013 over two climatic seasons (dry and wet) to constrain the interannual variability, seasonality and spatial heterogeneity of partial pressure of CO2 (pCO2) and CH4 concentrations and fluxes along the aquatic continuum, in relation to physico-chemical parameters (temperature, conductivity, oxygen, and pH) and various carbon pools (dissolved and particulate, organic and inorganic carbon, total alkalinity, primary production, respiration and net aquatic metabolism). Both pCO2 and CH4 variability was high, ranging from minimal values of 150 ppm and 7 nM, respectively, mainly in the two large reservoirs (the Kariba and the Cabora Bassa characterized by high pH and oxygen and low DOC), up to maximum values of 12,500 ppm and 12,130 nM, CO2 and CH4, respectively, mostly below floodplains/wetlands (low pH and oxygen levels, high DOC and POC concentrations). The interannual variability was relatively large for both CO2 and CH4 (mean pCO2: 2350 ppm in 2013 vs. 3180 ppm in 2013; mean CH4: 600 nM in 2012 vs. 1000 nM in 2013) and significantly higher (up to two fold) during wet season compared to dry season closely linked to distinct seasonal hydrological characteristics. Overall, no clear pattern was observed along the longitudinal gradient as river CO2 and CH4 concentrations are largely influenced by the presence of floodplains/wetlands, anthropogenic reservoirs or natural barriers (waterfalls/ rapids). Following closely the concentration patterns, river CO2 and CH4 mean fluxes of 3440 mg C-CO2 m

  5. Elevated CO2 decreases both transpiration flow and concentrations of Ca and Mg in the xylem sap of wheat.

    Science.gov (United States)

    Houshmandfar, Alireza; Fitzgerald, Glenn J; Tausz, Michael

    2015-02-01

    The impact of elevated atmospheric [CO2] (e[CO2]) on plants often includes a decrease in their nutrient status, including Ca and Mg, but the reasons for this decline have not been clearly identified. One of the proposed hypotheses is a decrease in transpiration-driven mass flow of nutrients due to decreased stomatal conductance. We used glasshouse and Free Air CO2 Enrichment (FACE) experiments with wheat to show that, in addition to decrease in transpiration rate, e[CO2] decreased the concentrations of Ca and Mg in the xylem sap. This result suggests that uptake of nutrients is not only decreased by reduced transpiration-driven mass flow, but also by as yet unidentified mechanisms that lead to reduced concentrations in the xylem sap. Copyright © 2014 Elsevier GmbH. All rights reserved.

  6. Variation in the leaf δ(13)C is correlated with salinity tolerance under elevated CO(2) concentration.

    Science.gov (United States)

    del Amor, Francisco M

    2013-02-15

    Increasing atmospheric CO(2) concentration is expected to impact agricultural systems through a direct effect on leaf gas exchange and also due to effects on the global availability of good-quality water as a result of climate warming. Thus, the planning of land use for agriculture requires new tools to identify the capability of current cultivars to adapt to growth restrictions under new ambient conditions. We hypothesized that salinity stress may produce a specific pattern of carbon isotopic composition (δ(13)C) in tomato (Solanum lycopersicum L.) at elevated CO(2) concentration ([CO(2)]) that could be used in the breeding of salinity tolerance in a near-future climate scenario. Five commercial tomato cultivars were evaluated at elevated (800 μmol mol(-1)) or standard (400 μmol mol(-1)) [CO(2)], being irrigated with a nutrient solution containing 0, 60 or 120 mM NaCl. The biomass enhanced ratio, leaf net CO(2) assimilation and stomatal conductance, leaf NO(3)(-) and Cl(-) concentrations and leaf free amino acid profile were analyzed in relation to the pattern of δ(13)C, under different saline stress conditions. The results indicate that at high [CO(2)]: (i) salinity tolerance was enhanced, but the response was strongly cultivar dependent, (ii) leaf NO(3)(-) concentration was increased whilst Cl(-) and proline concentrations decreased, and (iii) leaf δ(13)C was highly correlated with plant dry matter accumulation and with leaf proline concentration, leaf gas exchange and ion concentrations. This study shows that δ(13)C is a useful tool for the determination of the salinity tolerance of tomato at high [CO(2)], as an integrative parameter of the stress period, and was validated by traditional physiological plant stress traits. Copyright © 2012 Elsevier GmbH. All rights reserved.

  7. Combined effects of elevated temperature and CO2 concentration on Cd and Zn accumulation dynamics in Triticum aestivum L.

    Science.gov (United States)

    Wang, Xiaoheng; Li, Yu; Lu, Hong; Wang, Shigong

    2016-09-01

    A simulated climate warming experiment was conducted to evaluate the combined effects of elevated temperature and CO2 concentration on the bioaccumulation, translocation and subcellular distributions of Cd and Zn in wheat seedlings (Triticum aestivum L. cv. Xihan 1.) at Dingxi, Gansu Province, China. The objective was to find evidence that global climate change is affecting the bioaccumulation of Cd and Zn in T. aestivum L. cv. Xihan 1. The results showed that compared to control A, elevated temperature and CO2 increased Cd bioaccumulation in the shoots by 1.4-2.5 times, and increased that in the roots by 1.2-1.5 times, but decreased Zn levels in wheat shoots by 1.4-2.0 times, while decreased that in the roots by 1.6-1.9 times. Moreover, temperature and CO2 concentration increase also led to increased Cd concentration, and decreased Zn concentration in subcellular compartments of wheat seedlings. The largest Cd concentration increase (174.4%) was observed in the cell wall and debris fractions of shoots after they were subjected to the highest CO2 and temperature treatment (TC3). The largest Zn concentration decrease (53.1%) was observed in the soluble (F3) fractions of shoots after they were subjected to the medium CO2 and temperature treatment (TC2). The temperature and CO2 increase had no significant effect on the proportional distribution of Cd and Zn in the subcellular fractions. The root-to-shoot translocation of Cd increased with the increasing temperature and CO2 concentration. However, the Zn distributions only fluctuated within a small range. Copyright © 2016. Published by Elsevier B.V.

  8. Effects of elevated CO2 concentration on the polyamine levels of field-grown soybean at three O3 regimes.

    Science.gov (United States)

    Kramer, G F; Lee, E H; Rowland, R A; Mulchi, C L

    1991-01-01

    Effects of increased ozone (O3) and carbon dioxide (CO2) on polyamine levels were determined in soybean (Glycine max L. Merr. cv. Clark) grown in open-top field chambers. The chamber treatments consisted of three O3 regimes equal to charcoal filtered (CF), non-filtered (NF), and non-filtered plus 40 nl litre(-1) O3 and CO2 treatments equal to 350, 400 and 500 microl litre(-1) for a total of nine treatments. Leaf samples were taken at three different times during the growing season. Examination of growth and physiological characteristics, such as photosynthesis, stomatal resistance, and shoot weight, revealed that increasing CO2 ameliorated the deleterious effects of increased O3. Results from the initial harvest, at the pre-flowering growth stage (23 days of treatment), showed that increasing O3 at ambient CO2 caused increases in putrescine (Put) and spermidine (Spd) of up to six-fold. These effects were lessened with increased CO2. Elevated CO2 increased polyamines in plants treated with CF air, but had no effect in the presence of ambient or enhanced O3 levels. Leaves harvested during peak flowering (37 days of treatment) showed O3-induced increases in Put and Spd at ambient CO2 concentrations. However, increased CO2 levels inhibited this response by blocking the O3-induced polyamine increase. Leaves harvested during the pod fill stage (57 days of treatment) showed no significant O3 or CO2 effects on polyamine levels. Our results demonstrate that current ambient O3 levels induce the accumulation of Put and Spd early in the growing season and that further increases in O3 could result in even greater polyamine increases. These results are consistent with a possible antiozonant function for polyamines. The ability of increased CO2 to protect soybeans from O3 damage, however, does not appear to involve polyamine accumulation.

  9. Effect of elevated CO2 concentration and nitrate: ammonium ratios on gas exchange and growth of cassava (Manihot esculenta Crantz)

    Science.gov (United States)

    This study evaluated how different nitrogen forms affect growth and photosynthetic responses of cassava to CO2 concentration. Cassava was grown in 12-L pots in a greenhouse (30/25o C day / night) at 390 or 750 ppm of CO2. Three nitrogen treatments were applied: (a) 12 mM NO3-, (b) 6 mM NO3- + 6 mM N...

  10. Coupling Between the Changes in CO2 Concentration and Sediment Biogeochemistry in the Salinas De San Pedro Mudflat, California, USA

    Science.gov (United States)

    Rezaie Boroon, M.; Diaz, S.; Torres, V.; Lazzaretto, T.; Dehyn, D.

    2013-12-01

    We investigated the effects of elevated carbon dioxide [CO2] on biogeochemistry of marsh sediment including speciation of selected heavy metals in Salinas de San Pedro mudflat in California. The Salinas de San Pedro mudflat has higher carbon (C) content than the vast majority of fully-vegetated salt marshes even with the higher tidal action in the mudflat. Sources for CO2 were identified as atmospheric CO2 as well as due to local fault degassing process. We measured carbon dioxide [CO2], methane [CH4], total organic carbon, dissolved oxygen, salinity, and heavy metal concentration in various salt marsh locations. Overall, our results showed that CO2 concentration ranging from 418.7 to 436.9 [ppm], which are slightly different in various chambers but are in good agreement with some heavy metal concentrations values in mudflat at or around the same location. The selected metal concentration values (ppm) ranging from 0.003 - 0.011(As); 0.001-0.005 (Cd); 0.04-0.02 (Cr); 0.13-0.38 (Cu); 0.11-0.38 (Pb); 0.0009-0.020 (Se); and 0.188-0.321 (Zn). The low dissolved O2 [ppm] in the pore water sediment indicates suboxic environment. Additionally, CO2 [ppm] and loss on ignition (LOI) [%] correlated inversely; the higher CO2 content, the lower was the LOI; that is to say the excess CO2 may caused higher rates of decomposition and therefore it leads to lower soil organic matter (LOI) [%] on the mudflat surface. It appears that the elevated CO2 makes changes in salt marsh pore water chemistry for instance the free ionic metal (Cu2+, Pb2+, etc.) speciation is one of the most reactive form because simply assimilated by the non-decayed or alive organisms in sediment of salt marsh and/or in water. This means that CO2 not only is a sign of improvement in plant productivity, but also activates microbial decomposition through increases in dissolved organic carbon availability. CO2 also increases acidification processes such as anaerobic degradation of microorganism and oxidation of

  11. [Responses of non-structural carbohydrate metabolism of cucumber seedlings to drought stress and doubled CO2 concentration].

    Science.gov (United States)

    Dong, Yan-hong; Liu, Bin-bin; Zhang, Xu; Liu, Xue-na; Ai, Xi-zhen; Li, Qing-ming

    2015-01-01

    The effects of doubled CO2 concentration on non-structural carbohydrate metabolism of cucumber (Cucumis sativus L. cv. 'Jinyou No.1') seedlings under drought stress were investigated. Split plot design was deployed, with two levels of CO2 concentrations (ambient CO2 concentration, 380 µmol . mol-1, and doubled CO2 concentration, 760±20 µmol . mol-1) in the main plots, and three levels of water treatments (control, moderate drought stress, and severe drought stress) simulated by PEG 6000 in the split-plots. The results showed that non-structural carbohydrates of cucumber leaves, including glucose, fructose, sucrose, and stachyose, increased with the doubling of CO2 concentration, which resulted in the decreased osmotic potential, improving the drought stress in cucumber seedlings. During the drought stress, sucrose synthase, soluble acid invertase and al- kaline invertase started with an increase, and followed with a decline in the leaves. In the root system, however, soluble acid invertase and alkaline invertase increased gradually throughout the whole process, whereas sucrose phosphate synthase firstly increased and then decreased. The treatment of doubled CO2 enhanced the activity of sucrose synthase, but decreased the activity of sucrose phosphate synthase. The synergistic action of the two enzymes and invertase accelerated the decomposition of sucrose and inhibited the synthesis of sucrose, leading to the accumulation of hexose, which lowered the cellular osmotic potential and enhanced the water uptake capacity. In conclusion, doubled CO2 concentration could alleviate the adverse effects of drought stress and improve the drought tolerance of cucumber seedlings. Such mitigating effect on cucumber was more significant under severe drought stress.

  12. Adaptation to high CO2 concentration in an optimal environment: radiation capture, canopy quantum yield and carbon use efficiency

    Science.gov (United States)

    Monje, O.; Bugbee, B.

    1998-01-01

    The effect of elevated [CO2] on wheat (Triticum aestivum L. Veery 10) productivity was examined by analysing radiation capture, canopy quantum yield, canopy carbon use efficiency, harvest index and daily C gain. Canopies were grown at either 330 or 1200 micromoles mol-1 [CO2] in controlled environments, where root and shoot C fluxes were monitored continuously from emergence to harvest. A rapidly circulating hydroponic solution supplied nutrients, water and root zone oxygen. At harvest, dry mass predicted from gas exchange data was 102.8 +/- 4.7% of the observed dry mass in six trials. Neither radiation capture efficiency nor carbon use efficiency were affected by elevated [CO2], but yield increased by 13% due to a sustained increase in canopy quantum yield. CO2 enrichment increased root mass, tiller number and seed mass. Harvest index and chlorophyll concentration were unchanged, but CO2 enrichment increased average life cycle net photosynthesis (13%, P < 0.05) and root respiration (24%, P < 0.05). These data indicate that plant communities adapt to CO2 enrichment through changes in C allocation. Elevated [CO2] increases sink strength in optimal environments, resulting in sustained increases in photosynthetic capacity, canopy quantum yield and daily C gain throughout the life cycle.

  13. Effect of carbonic anhydrase on silicate weathering and carbonate formation at present day CO2 concentrations compared to primordial values

    Science.gov (United States)

    Xiao, Leilei; Lian, Bin; Hao, Jianchao; Liu, Congqiang; Wang, Shijie

    2015-01-01

    It is widely recognized that carbonic anhydrase (CA) participates in silicate weathering and carbonate formation. Nevertheless, it is still not known if the magnitude of the effect produced by CA on surface rock evolution changes or not. In this work, CA gene expression from Bacillus mucilaginosus and the effects of recombination protein on wollastonite dissolution and carbonate formation under different conditions are explored. Real-time fluorescent quantitative PCR was used to explore the correlation between CA gene expression and sufficiency or deficiency in calcium and CO2 concentration. The results show that the expression of CA genes is negatively correlated with both CO2 concentration and ease of obtaining soluble calcium. A pure form of the protein of interest (CA) is obtained by cloning, heterologous expression, and purification. The results from tests of the recombination protein on wollastonite dissolution and carbonate formation at different levels of CO2 concentration show that the magnitudes of the effects of CA and CO2 concentration are negatively correlated. These results suggest that the effects of microbial CA in relation to silicate weathering and carbonate formation may have increased importance at the modern atmospheric CO2 concentration compared to 3 billion years ago. PMID:25583135

  14. Rainfall distribution is the main driver of runoff under future CO2-concentration in a temperate deciduous forest

    Science.gov (United States)

    Leuzinger, S.; Körner, C.

    2009-04-01

    Reduced stomatal conductance under elevated CO2 results in increased soil moisture, provided all other factors remain constant. Whether this results in increased runoff critically depends on the interaction of rainfall patterns, soil water storage capacity and plant responses. To test the sensitivity of runoff to these parameters under elevated CO2, we combine transpiration and soil moisture data from the Swiss Canopy Crane (SCC) FACE experiment with 104 years of daily precipitation data from an adjacent weather station to drive a three-layer bucket model (mean yearly precipitation 794 mm). The model adequately predicts the water budget of a temperate deciduous forest and runoff from a nearby gauging station. A simulation run over all 104 years based on sap flow responses resulted in only 5.5 mm (2.9 %) increased ecosystem runoff under elevated CO2. Out of the 37986 days (1.1.1901 to 31.12.2004), only 576 days produce higher runoff under in the elevated CO2 scenario. Only 1 out of 17 years produces a CO2-signal greater than 20 mma-1, which mostly depends on a few single days when runoff under elevated CO2 exceeds runoff under ambient conditions. The maximum signal for a double pre-industrial CO2-concentration under the past century daily rainfall regime is an additional runoff of 46 mm (year 1938). More than half of all years produce a signal of less than 5 mma-1, because trees consume the 'extra' moisture during prolonged dry weather. Increased runoff under elevated CO2 is 9 times more sensitive to variations in rain pattern than to the applied reduction in transpiration under elevated CO2. Thus the key driver of increased runoff under future CO2-concentration is the day by day rainfall pattern. We argue that increased runoff due to a first-order plant physiological CO2-effect will be very small (<3 %) in the landscape dominated by temperate deciduous forests, and will hardly increase flooding risk in forest catchments. It is likely that these results are equally

  15. Elevated CO2 response of photosynthesis depends on ozone concentration in aspen

    Science.gov (United States)

    Asko Noormets; Olevi Kull; Anu Sober; Mark E. Kubiske; David F. Karnosky

    2010-01-01

    The effect of elevated CO2 and O3 on apparent quantum yield (ø), maximum photosynthesis (Pmax), carboxylation efficiency (Vcmax) and electron transport capacity (Jmax) at different canopy locations was studied in two aspen (Populus...

  16. NACP MCI: Tower Atmospheric CO2 Concentrations, Upper Midwest Region, USA, 2007-2009

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides high precision and high accuracy atmospheric CO2 data from seven instrumented communication towers located in the U.S. Upper Midwest. The...

  17. Effects of temperature, pH, water activity and CO2 concentration on growth of Rhizopus oligosporus NRRL 2710.

    Science.gov (United States)

    Sparringa, R A; Kendall, M; Westby, A; Owens, J D

    2002-01-01

    To investigate the effects of temperature, pH, water activity (aw) and CO2 concentration on the growth of Rhizopus oligosporus NRRL 2710. Hyphal extension rates from mycelial and spore inocula were measured on media with different aw (approximately 1.0, 0.98 and 0.96) and pH (3.5, 5.5 and 7.5) incubated at 30, 37 or 42 degrees C in atmospheres containing 0.03, 12.5 or 25% (v/v) CO2. The effects of environmental conditions on hyphal extension rate were modelled using surface response methodology. The rate of hyphal extension was very sensitive to pH, exhibiting a pronounced optimum at pH 5.5-5.8. The hyphal extension rate was less sensitive to temperature, aw or CO2, exhibiting maximum rates at 42 degrees C, a(w) approximately 1.0 and 0.03% (v/v) CO2. The fastest hyphal extension rate (1.7 mm h(-1)) was predicted to occur at 42 degrees C, pH 5.85, a(w) approximately 1.0 and 0.03% CO2. The present work is the first to model the simultaneous effects of temperature, pH, aw and CO2 concentration on mould growth. The information relates to tempe fermentation and to possible control of the microflora in Tanzanian cassava heap fermentations.

  18. Lethal and sub-lethal effects of elevated CO2 concentrations on marine benthic invertebrates and fish.

    Science.gov (United States)

    Lee, Changkeun; Hong, Seongjin; Kwon, Bong-Oh; Lee, Jung-Ho; Ryu, Jongseong; Park, Young-Gyu; Kang, Seong-Gil; Khim, Jong Seong

    2016-08-01

    Concern about leakage of carbon dioxide (CO2) from deep-sea storage in geological reservoirs is increasing because of its possible adverse effects on marine organisms locally or at nearby coastal areas both in sediment and water column. In the present study, we examined how elevated CO2 affects various intertidal epibenthic (benthic copepod), intertidal endobenthic (Manila clam and Venus clam), sub-tidal benthic (brittle starfish), and free-living (marine medaka) organisms in areas expected to be impacted by leakage. Acute lethal and sub-lethal effects were detected in the adult stage of all test organisms exposed to varying concentrations of CO2, due to the associated decline in pH (8.3 to 5.2) during 96-h exposure. However, intertidal organisms (such as benthic copepods and clams) showed remarkable resistance to elevated CO2, with the Venus clam being the most tolerant (LpH50 = 5.45). Sub-tidal species (such as brittle starfish [LpH50 = 6.16] and marine medaka [LpH50 = 5.91]) were more sensitive to elevated CO2 compared to intertidal species, possibly because they have fewer defensive capabilities. Of note, the exposure duration might regulate the degree of acute sub-lethal effects, as evidenced by the Venus clam, which showed a time-dependent effect to elevated CO2. Finally, copper was chosen as a model toxic element to find out the synergistic or antagonistic effects between ocean acidification and metal pollution. Combination of CO2 and Cu exposure enhances the adverse effects to organisms, generally supporting a synergistic effect scenario. Overall, the significant variation in the degree to which CO2 adversely affected organisms (viz., working range and strength) was clearly observed, supporting the general concept of species-dependent effects of elevated CO2.

  19. The counteracting effects of elevated atmospheric CO2 concentrations and drought episodes: Studies of enchytraeid communities in a dry heathland

    DEFF Research Database (Denmark)

    Maraldo, Kristine; Krogh, Paul Henning; Linden, Leon

    2010-01-01

    The potential impacts of interactions of multiple climate change factors in soil ecosystems have received little attention. Most studies have addressed effects of single factors such as increased temperature or atmospheric CO2 but little is known about how such environmental factors will interact....... In the present study we investigate the effects of in situ exposure to elevated atmospheric CO2 concentration, increased temperatures and prolonged drought episodes on field communities of Enchytraeidae (Oligochaeta) in a dry heathland (Brandbjerg, Denmark). Increased CO2 had a positive effect on enchytraeid...... biomass, whereas drought significantly reduced it. Elevated temperature did not result in any detectable effects. No interactions between the three factors were observed. Interestingly, the positive effect of increased CO2 and the negative effect of drought were cancelled out when applied in combination...

  20. The effects of elevated CO2 concentration on competitive interaction between aceticlastic and syntrophic methanogenesis in a model microbial consortium.

    Science.gov (United States)

    Kato, Souichiro; Yoshida, Rina; Yamaguchi, Takashi; Sato, Tomoyuki; Yumoto, Isao; Kamagata, Yoichi

    2014-01-01

    Investigation of microbial interspecies interactions is essential for elucidating the function and stability of microbial ecosystems. However, community-based analyses including molecular-fingerprinting methods have limitations for precise understanding of interspecies interactions. Construction of model microbial consortia consisting of defined mixed cultures of isolated microorganisms is an excellent method for research on interspecies interactions. In this study, a model microbial consortium consisting of microorganisms that convert acetate into methane directly (Methanosaeta thermophila) and syntrophically (Thermacetogenium phaeum and Methanothermobacter thermautotrophicus) was constructed and the effects of elevated CO2 concentrations on intermicrobial competition were investigated. Analyses on the community dynamics by quantitative RT-PCR and fluorescent in situ hybridization targeting their 16S rRNAs revealed that high concentrations of CO2 have suppressive effects on the syntrophic microorganisms, but not on the aceticlastic methanogen. The pathways were further characterized by determining the Gibbs free energy changes (ΔG) of the metabolic reactions conducted by each microorganism under different CO2 concentrations. The ΔG value of the acetate oxidation reaction (T. phaeum) under high CO2 conditions became significantly higher than -20 kJ per mol of acetate, which is the borderline level for sustaining microbial growth. These results suggest that high concentrations of CO2 undermine energy acquisition of T. phaeum, resulting in dominance of the aceticlastic methanogen. This study demonstrates that investigation on model microbial consortia is useful for untangling microbial interspecies interactions, including competition among microorganisms occupying the same trophic niche in complex microbial ecosystems.

  1. Does long-term cultivation of saplings under elevated CO2 concentration influence their photosynthetic response to temperature?

    Science.gov (United States)

    Šigut, Ladislav; Holišová, Petra; Klem, Karel; Šprtová, Mirka; Calfapietra, Carlo; Marek, Michal V.; Špunda, Vladimír; Urban, Otmar

    2015-01-01

    Background and Aims Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. This study therefore tested the hypothesis that under long-term elevated CO2 the temperature optima of photosynthetic processes will shift towards higher temperatures and the thermostability of the photosynthetic apparatus will increase. Methods The hypothesis was tested for saplings of broadleaved Fagus sylvatica and coniferous Picea abies exposed for 4–5 years to either ambient (AC; 385 µmol mol−1) or elevated (EC; 700 µmol mol−1) CO2 concentrations. Temperature response curves of photosynthetic processes were determined by gas-exchange and chlorophyll fluorescence techniques. Key Results Initial assumptions of reduced light-saturated stomatal conductance and increased leaf temperatures for EC plants were confirmed. Temperature response curves revealed stimulation of light-saturated rates of CO2 assimilation (Amax) and a decline in photorespiration (RL) as a result of EC within a wide temperature range. However, these effects were negligible or reduced at low and high temperatures. Higher temperature optima (Topt) of Amax, Rubisco carboxylation rates (VCmax) and RL were found for EC saplings compared with AC saplings. However, the shifts in Topt of Amax were instantaneous, and disappeared when measured at identical CO2 concentrations. Higher values of Topt at elevated CO2 were attributed particularly to reduced photorespiration and prevailing limitation of photosynthesis by ribulose-1,5-bisphosphate (RuBP) regeneration. Temperature response curves of fluorescence parameters suggested a negligible effect of EC on enhancement of thermostability of photosystem II photochemistry. Conclusions Elevated CO2 instantaneously increases temperature optima of Amax due to reduced photorespiration and limitation of photosynthesis by RuBP regeneration. However, this increase disappears when plants

  2. Changes in the activities of starch metabolism enzymes in rice grains in response to elevated CO2 concentration.

    Science.gov (United States)

    Xie, Li-Yong; Lin, Er-Da; Zhao, Hong-Liang; Feng, Yong-Xiang

    2016-05-01

    The global atmospheric CO(2) concentration is currently (2012) 393.1 μmol mol(-1), an increase of approximately 42 % over pre-industrial levels. In order to understand the responses of metabolic enzymes to elevated CO(2) concentrations, an experiment was conducted using the Free Air CO(2) Enrichment (FACE )system. Two conventional japonica rice varieties (Oryza sativa L. ssp. japonica) grown in North China, Songjing 9 and Daohuaxiang 2, were used in this study. The activities of ADPG pyrophosphorylase, soluble and granule-bound starch synthases, and soluble and granule-bound starch branching enzymes were measured in rice grains, and the effects of elevated CO(2) on the amylose and protein contents of the grains were analyzed. The results showed that elevated CO(2) levels significantly increased the activity of ADPG pyrophosphorylase at day 8, 24, and 40 after flower, with maximum increases of 56.67 % for Songjing 9 and 21.31 % for Daohuaxiang 2. Similarly, the activities of starch synthesis enzymes increased significantly from the day 24 after flower to the day 40 after flower, with maximum increases of 36.81 % for Songjing 9 and 66.67 % for Daohuaxiang 2 in soluble starch synthase (SSS), and 25.00 % for Songjing 9 and 36.44 % for Daohuaxiang 2 in granule-bound starch synthase (GBSS), respectively. The elevated CO(2) concentration significantly increased the activity of soluble starch branching enzyme (SSBE) at day 16, 32, and 40 after flower, and also significantly increased the activity of granule-bound starch branching enzyme (GBSBE) at day 8, 32, and 40 after flower. The elevated CO(2) concentration increased the peak values of enzyme activity, and the timing of the activity peaks for SSS and GBSBE were earlier in Songjing 9 than in Daohuaxiang 2. There were obvious differences in developmental stages between the two varieties of rice, which indicated that the elevated CO(2) concentration increased enzyme activity expression and starch synthesis, affecting the

  3. Atmospheric CO2 concentration impacts on maize yield performance under dry conditions: do crop model simulate it right ?

    Science.gov (United States)

    Durand, Jean-Louis; Delusca, Kénel; Boote, Ken; Lizaso, Jon; Manderscheid, Remy; Jochaim Weigel, Hans; Ruane, Alex C.; Rosenzweig, Cynthia; Jones, Jim; Ahuja, Laj; Anapalli, Saseendran; Basso, Bruno; Baron, Christian; Bertuzzi, Patrick; Biernath, Christian; Deryng, Delphine; Ewert, Frank; Gaiser, Thomas; Gayler, Sebastian; Heinlein, Florian; Kersebaum, Kurt Christian; Kim, Soo-Hyung; Müller, Christoph; Nendel, Claas; Olioso, Albert; Priesack, Eckhart; Ramirez-Villegas, Julian; Ripoche, Dominique; Rötter, Reimund; Seidel, Sabine; Srivastava, Amit; Tao, Fulu; Timlin, Dennis; Twine, Tracy; Wang, Enli; Webber, Heidi; Zhao, Shigan

    2017-04-01

    In most regions of the world, maize yields are at risk of be reduced due to rising temperatures and reduced water availability. Rising temperature tends to reduce the length of the growth cycle and the amount of intercepted solar energy. Water deficits reduce the leaf area expansion, photosynthesis and sometimes, with an even more pronounced impact, severely reduce the efficiency of kernel set. In maize, the major consequence of atmospheric CO2 concentration ([CO2]) is the stomatal closure-induced reduction of leaf transpiration rate, which tends to mitigate those negative impacts. Indeed FACE studies report significant positive responses to CO2 of maize yields (and other C4 crops) under dry conditions only. Given the projections by climatologists (typically doubling of [CO2] by the end of this century) projected impacts must take that climate variable into account. However, several studies show a large incertitude in estimating the impact of increasing [CO2] on maize remains using the main crop models. The aim of this work was to compare the simulations of different models using input data from a FACE experiment conducted in Braunschweig during 2 years under limiting and non-limiting water conditions. Twenty modelling groups using different maize models were given the same instructions and input data. Following calibration of cultivar parameters under non-limiting water conditions and under ambient [CO2] treatments of both years, simulations were undertaken for the other treatments: High [ CO2 ] (550 ppm) 2007 and 2008 in both irrigation regimes, and DRY AMBIENT 2007 and 2008. Only under severe water deficits did models simulate an increase in yield for CO2 enrichment, which was associated with higher harvest index and, for those models which simulated it, higher grain number. However, the CO2 enhancement under water deficit simulated by the 20 models was 20 % at most and 10 % on average only, i.e. twice less than observed in that experiment. As in the experiment

  4. Interactive effects of elevated CO2 concentration and irrigation on photosynthetic parameters and yield of maize in Northeast China.

    Directory of Open Access Journals (Sweden)

    Fanchao Meng

    Full Text Available Maize is one of the major cultivated crops of China, having a central role in ensuring the food security of the country. There has been a significant increase in studies of maize under interactive effects of elevated CO2 concentration ([CO2] and other factors, yet the interactive effects of elevated [CO2] and increasing precipitation on maize has remained unclear. In this study, a manipulative experiment in Jinzhou, Liaoning province, Northeast China was performed so as to obtain reliable results concerning the later effects. The Open Top Chambers (OTCs experiment was designed to control contrasting [CO2] i.e., 390, 450 and 550 µmol·mol(-1, and the experiment with 15% increasing precipitation levels was also set based on the average monthly precipitation of 5-9 month from 1981 to 2010 and controlled by irrigation. Thus, six treatments, i.e. C550W+15%, C550W0, C450W+15%, C450W0, C390W+15% and C390W0 were included in this study. The results showed that the irrigation under elevated [CO2] levels increased the leaf net photosynthetic rate (Pn and intercellular CO2 concentration (Ci of maize. Similarly, the stomatal conductance (Gs and transpiration rate (Tr decreased with elevated [CO2], but irrigation have a positive effect on increased of them at each [CO2] level, resulting in the water use efficiency (WUE higher in natural precipitation treatment than irrigation treatment at elevated [CO2] levels. Irradiance-response parameters, e.g., maximum net photosynthetic rate (Pnmax and light saturation points (LSP were increased under elevated [CO2] and irrigation, and dark respiration (Rd was increased as well. The growth characteristics, e.g., plant height, leaf area and aboveground biomass were enhanced, resulting in an improved of yield and ear characteristics except axle diameter. The study concluded by reporting that, future elevated [CO2] may favor to maize when coupled with increasing amount of precipitation in Northeast China.

  5. Interactive effects of elevated CO2 concentration and irrigation on photosynthetic parameters and yield of maize in Northeast China.

    Science.gov (United States)

    Meng, Fanchao; Zhang, Jiahua; Yao, Fengmei; Hao, Cui

    2014-01-01

    Maize is one of the major cultivated crops of China, having a central role in ensuring the food security of the country. There has been a significant increase in studies of maize under interactive effects of elevated CO2 concentration ([CO2]) and other factors, yet the interactive effects of elevated [CO2] and increasing precipitation on maize has remained unclear. In this study, a manipulative experiment in Jinzhou, Liaoning province, Northeast China was performed so as to obtain reliable results concerning the later effects. The Open Top Chambers (OTCs) experiment was designed to control contrasting [CO2] i.e., 390, 450 and 550 µmol·mol(-1), and the experiment with 15% increasing precipitation levels was also set based on the average monthly precipitation of 5-9 month from 1981 to 2010 and controlled by irrigation. Thus, six treatments, i.e. C550W+15%, C550W0, C450W+15%, C450W0, C390W+15% and C390W0 were included in this study. The results showed that the irrigation under elevated [CO2] levels increased the leaf net photosynthetic rate (Pn) and intercellular CO2 concentration (Ci) of maize. Similarly, the stomatal conductance (Gs) and transpiration rate (Tr) decreased with elevated [CO2], but irrigation have a positive effect on increased of them at each [CO2] level, resulting in the water use efficiency (WUE) higher in natural precipitation treatment than irrigation treatment at elevated [CO2] levels. Irradiance-response parameters, e.g., maximum net photosynthetic rate (Pnmax) and light saturation points (LSP) were increased under elevated [CO2] and irrigation, and dark respiration (Rd) was increased as well. The growth characteristics, e.g., plant height, leaf area and aboveground biomass were enhanced, resulting in an improved of yield and ear characteristics except axle diameter. The study concluded by reporting that, future elevated [CO2] may favor to maize when coupled with increasing amount of precipitation in Northeast China.

  6. Modeling and optimization of a concentrated solar supercritical CO2 power plant

    Science.gov (United States)

    Osorio, Julian D.

    Renewable energy sources are fundamental alternatives to supply the rising energy demand in the world and to reduce or replace fossil fuel technologies. In order to make renewable-based technologies suitable for commercial and industrial applications, two main challenges need to be solved: the design and manufacture of highly efficient devices and reliable systems to operate under intermittent energy supply conditions. In particular, power generation technologies based on solar energy are one of the most promising alternatives to supply the world energy demand and reduce the dependence on fossil fuel technologies. In this dissertation, the dynamic behavior of a Concentrated Solar Power (CSP) supercritical CO2 cycle is studied under different seasonal conditions. The system analyzed is composed of a central receiver, hot and cold thermal energy storage units, a heat exchanger, a recuperator, and multi-stage compression-expansion subsystems with intercoolers and reheaters between compressors and turbines respectively. The effects of operating and design parameters on the system performance are analyzed. Some of these parameters are the mass flow rate, intermediate pressures, number of compression-expansion stages, heat exchangers' effectiveness, multi-tank thermal energy storage, overall heat transfer coefficient between the solar receiver and the environment and the effective area of the recuperator. Energy and exergy models for each component of the system are developed to optimize operating parameters in order to lead to maximum efficiency. From the exergy analysis, the components with high contribution to exergy destruction were identified. These components, which represent an important potential of improvement, are the recuperator, the hot thermal energy storage tank and the solar receiver. Two complementary alternatives to improve the efficiency of concentrated solar thermal systems are proposed in this dissertation: the optimization of the system's operating

  7. Automated system for simultaneous analysis of delta(13)C, delta(18)O and CO(2) concentrations in small air samples.

    Science.gov (United States)

    Ribas-Carbo, Miquel; Still, Chris; Berry, Joe

    2002-01-01

    In this paper we present an automated system for simultaneous measurement of CO(2) concentration, delta(13)C and delta(18)O from small (CMDL analyzed air samples was 0.08 ppm for the CO(2) concentration, 0.01 per thousand for delta(13)C and 0.00 per thousand for delta(18)O. A specific list of the parts and operation of the system is detailed as well as some of the applications for micrometeorological and ecophysiological applications. Copyright 2002 John Wiley & Sons, Ltd.

  8. The sensitivity of photosynthesis to O2 and CO2 concentration identifies strong Rubisco control above the thermal optimum.

    Science.gov (United States)

    Busch, Florian A; Sage, Rowan F

    2017-02-01

    The biochemical model of C3 photosynthesis by Farquhar, von Caemmerer and Berry (FvCB) assumes that photosynthetic CO2 assimilation is limited by one of three biochemical processes that are not always easily discerned. This leads to improper assessments of biochemical limitations that limit the accuracy of the model predictions. We use the sensitivity of rates of CO2 assimilation and photosynthetic electron transport to changes in O2 and CO2 concentration in the chloroplast to evaluate photosynthetic limitations. Assessing the sensitivities to O2 and CO2 concentrations reduces the impact of uncertainties in the fixed parameters to a minimum and simultaneously entirely eliminates the need to determine the variable parameters of the model, such as Vcmax , J, or TP . Our analyses demonstrate that Rubisco limits carbon assimilation at high temperatures, while it is limited by triose phosphate utilization at lower temperatures and at higher CO2 concentrations. Measurements can be assigned a priori to one of the three functions of the FvCB model, allowing testing for the suitability of the selected fixed parameters of the model. This approach can improve the reliability of photosynthesis models on scales from the leaf level to estimating the global carbon budget. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  9. Key knowledge and data gaps in modelling the influence of CO2 concentration on the terrestrial carbon sink.

    Science.gov (United States)

    Pugh, T A M; Müller, C; Arneth, A; Haverd, V; Smith, B

    2016-09-20

    Primary productivity of terrestrial vegetation is expected to increase under the influence of increasing atmospheric carbon dioxide concentrations ([CO2]). Depending on the fate of such additionally fixed carbon, this could lead to an increase in terrestrial carbon storage, and thus a net terrestrial sink of atmospheric carbon. Such a mechanism is generally believed to be the primary global driver behind the observed large net uptake of anthropogenic CO2 emissions by the biosphere. Mechanisms driving CO2 uptake in the Terrestrial Biosphere Models (TBMs) used to attribute and project terrestrial carbon sinks, including that from increased [CO2], remain in large parts unchanged since those models were conceived two decades ago. However, there exists a large body of new data and understanding providing an opportunity to update these models, and directing towards important topics for further research. In this review we highlight recent developments in understanding of the effects of elevated [CO2] on photosynthesis, and in particular on the fate of additionally fixed carbon within the plant with its implications for carbon turnover rates, on the regulation of photosynthesis in response to environmental limitations on in-plant carbon sinks, and on emergent ecosystem responses. We recommend possible avenues for model improvement and identify requirements for better data on core processes relevant to the understanding and modelling of the effect of increasing [CO2] on the global terrestrial carbon sink. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

  10. Engineering the Cyanobacterial Carbon Concentrating Mechanism for Enhanced CO2 Capture and Fixation

    Energy Technology Data Exchange (ETDEWEB)

    Sandh, Gustaf; Cai, Fei; Shih, Patrick; Kinney, James; Axen, Seth; Salmeen, Annette; Zarzycki, Jan; Sutter, Markus; Kerfeld, Cheryl

    2011-06-02

    In cyanobacteria CO2 fixation is localized in a special proteinaceous organelle, the carboxysome. The CO2 fixation enzymes are encapsulated by a selectively permeable protein shell. By structurally and functionally characterizing subunits of the carboxysome shell and the encapsulated proteins, we hope to understand what regulates the shape, assembly and permeability of the shell, as well as the targeting mechanism and organization of the encapsulated proteins. This knowledge will be used to enhance CO2 fixation in both cyanobacteria and plants through synthetic biology. The same strategy can also serve as a template for the production of modular synthetic bacterial organelles. Our research is conducted using a variety of techniques such as genomic sequencing and analysis, transcriptional regulation, DNA synthesis, synthetic biology, protein crystallization, Small Angle X-ray Scattering (SAXS), protein-protein interaction assays and phenotypic characterization using various types of cellular imaging, e.g. fluorescence microscopy, Transmission Electron Microscopy (TEM), and Soft X-ray Tomography (SXT).

  11. Laser Sounder for Measuring Atmospheric CO2 Concentrations: Progress Toward Ascends

    Science.gov (United States)

    Abshire, J. B.; Kawa, S. R.; Riris, H.; Allan, G. R.; Sun, X.; Stephen, M. A.; Wilson, E.; Burris, J. F.; Mao, J.

    2008-01-01

    The next generation of space-based, active remote sensing instruments for measurement of tropospheric CO2 promises a capability to quantify global carbon sources and sinks at regional scales. Active (laser) methods will extend CO2 measurement coverage in time, space, and perhaps precision such that the underlying mechanisms for carbon exchange at the surface can be understood with .sufficient detail to confidently project the future of carbon-climate interaction and the influence of remediative policy actions. The recent Decadal Survey for Earth Science by the US National Research Council has recommended such a mission called the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) for launch in 2013-2016. We have been developing a laser technique for measurement of tropospheric CO2 for a number of years. Our immediate goal is to develop and demonstrate the method and instrument technology that will permit measurements of the CO2 column abundance over a horizontal path and from aircraft at the few-ppmv level. Our longer-term goal is to demonstrate the required capabilities of the technique, develop a space mission approach, and design the instrument for an ASCENDS-type mission. Our approach is to use a dual channel laser absorption spectrometer (i.e., differential absorption in altimeter mode), which continuously measures from a near-polar circular orbit. We use several co-aligned tunable fiber laser transmitters allowing simultaneous measurement of the absorption from a CO2 line in the 1570 nm band, O2 extinction in the oxygen A-band (near 765 nm), and aerosol backscatter in the same measurement path. We measure the energy of the laser echoes at nadir reflected from land and water surfaces, day and night. The lasers have spectral widths much narrower than the gas absorption lines and are turned on and off the selected CO2 and O2 lines at kHz rates. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of

  12. Airborne Measurements of CO2 Column Concentration and Range Using a Pulsed Direct-Detection IPDA Lidar

    Directory of Open Access Journals (Sweden)

    James B. Abshire

    2013-12-01

    Full Text Available We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The lidar measures the atmospheric backscatter profiles and samples the shape of the 1,572.33 nm CO2 absorption line. We participated in the ASCENDS science flights on the NASA DC-8 aircraft during August 2011 and report here lidar measurements made on four flights over a variety of surface and cloud conditions near the US. These included over a stratus cloud deck over the Pacific Ocean, to a dry lake bed surrounded by mountains in Nevada, to a desert area with a coal-fired power plant, and from the Rocky Mountains to Iowa, with segments with both cumulus and cirrus clouds. Most flights were to altitudes >12 km and had 5–6 altitude steps. Analyses show the retrievals of lidar range, CO2 column absorption, and CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds, between cumulus clouds, and to stratus cloud tops. The retrievals shows the decrease in column CO2 due to growing vegetation when flying over Iowa cropland as well as a sudden increase in CO2 concentration near a coal-fired power plant. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption lineshape (averaged for 50 s matched the predicted shapes to better than 1% RMS error. For 10 s averaging, the scatter in the retrievals was typically 2–3 ppm and was limited by the received signal photon count. Retrievals were made using atmospheric parameters from both an atmospheric model and from in situ temperature and pressure from the aircraft. The retrievals had no free parameters and did not use empirical adjustments, and >70% of the measurements passed screening and were used in analysis. The differences between the lidar-measured retrievals and in situ measured average CO2 column concentrations were <1.4 ppm for flight measurement altitudes >6

  13. Interpretation and evaluation of combined measurement techniques for soil CO2 efflux: Discrete surface chambers and continuous soil CO2 concentration probes

    Science.gov (United States)

    Diego A. Riveros-Iregui; Brian L. McGlynn; Howard E. Epstein; Daniel L. Welsch

    2008-01-01

    Soil CO2 efflux is a large respiratory flux from terrestrial ecosystems and a critical component of the global carbon (C) cycle. Lack of process understanding of the spatiotemporal controls on soil CO2 efflux limits our ability to extrapolate from fluxes measured at point scales to scales useful for corroboration with other ecosystem level measures of C exchange....

  14. Effect of polymer concentration on the structure and performance of PEI hollow fiber membrane contactor for CO2 stripping.

    Science.gov (United States)

    Naim, R; Ismail, A F

    2013-04-15

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13-16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10(-2)mol/m(2)s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. High-Pressure Measurements of Temperature and CO2 Concentration Using Tunable Diode Lasers at 2 μm.

    Science.gov (United States)

    Cai, Tingdong; Gao, Guangzhen; Wang, Minrui; Wang, Guishi; Liu, Ying; Gao, Xiaoming

    2016-03-01

    A sensor for simultaneous measurements of temperature and carbon dioxide (CO2) concentration at elevated pressure is developed using tunable diode lasers at 2 µm. Based on some selection rules, a CO2 line pair at 5006.140 and 5010.725 cm(-1) is selected for the TDL sensor. In order to ensure the accuracy and rapidity of the sensor, a quasi-fixed-wavelength WMS is employed. Normalization of the 2f signal with the 1f signal magnitude is used to remove the need for calibration and correct for transmission variation due to beam steering, mechanical misalignments, soot, and windows fouling. Temperatures are obtained from comparison of the background-subtracted 1f-normalized WMS-2f signals ratio and a 1f-normalized WMS-2f peak values ratio model. CO2 concentration is inferred from the 1f-normalized WMS-2f peak values of the CO2 transition at 5006.140 cm(-1). Measurements of temperature and CO2 concentration are carried out in static cell experiments (P = 1-10 atm, T = 500-1200 K) to validate the accuracy and ability of the sensor. The results show that accuracy of the sensor for temperature and CO2 concentration are 1.66% temperature and 3.1%, respectively. All the measurements show the potential utility of the sensor for combustion diagnose at elevated pressure. © The Author(s) 2016.

  16. [Influence of elevated atmospheric CO2 concentration on photosynthesis and leaf nitrogen partition in process of photosynthetic carbon cycle in Musa paradisiaca].

    Science.gov (United States)

    Sun, G; Zhao, P; Zeng, X; Peng, S

    2001-06-01

    The photosynthetic rate (Pn) in leaves of Musa paradisiaca grown under elevated CO2 concentration (700 +/- 56 microliters.L-1) for one week was 5.14 +/- 0.32 mumol.m-2.s-1, 22.1% higher than that under ambient CO2 concentration, while under elevated CO2 concentration for 8 week, the Pn decreased by 18.1%. It can be inferred that the photosynthetic acclimation to elevated CO2 concentration and the Pn inhibition occurred in leaves of M. paradisiaca. The respiration rate in light (Rd) was lower in leaves under higher CO2 concentration, compared with that under ambient CO2 concentration. If the respiration in light was not included, the difference in CO2 compensation point for the leaves of both plants was not significant. Under higher CO2 concentration for 8 weeks, the maximum carboxylation rate(Vcmax) and electron transportation rate (J) in leaves decreased respectively by 30.5% and 14.8%, compared with that under ambient CO2 concentration. The calculated apparent quantum yield (alpha) in leaves under elevated CO2 concentration according to the initial slope of Pn/PAR was reduced to 0.014 +/- 0.010 molCO2.mol-1 quanta, compared with the value of 0.025 +/- 0.005 molCO2.mol-1 quanta in the control. The efficiency of light energy conversion also decreased from 0.203 to 0.136 electrons.quanta-1 in plants under elevated CO2 concentration. A lower partitioning coefficient for leaf nitrogen in Rubisco, bioenergetics and thylakoid light-harvesting components was observed in plants under higher CO2 concentration. The results indicated that the multi-process of photosynthesis was suppressed significantly by a long-term (8 weeks) higher CO2 concentration incubation.

  17. CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants.

    Science.gov (United States)

    Bloom, Arnold J; Asensio, Jose Salvador Rubaio; Randall, Lesley; Rachmilevitch, Shimon; Cousins, Asaph B; Carlisle, Eli A

    2012-02-01

    The CO2 concentration in Earth's atmosphere may double during this century. Plant responses to such an increase depend strongly on their nitrogen status, but the reasons have been uncertain. Here, we assessed shoot nitrate assimilation into amino acids via the shift in shoot CO2 and O2 fluxes when plants received nitrate instead of ammonium as a nitrogen source (deltaAQ). Shoot nitrate assimilation became negligible with increasing CO2 in a taxonomically diverse group of eight C3 plant species, was relatively insensitive to CO2 in three C4 species, and showed an intermediate sensitivity in two C3-C4 intermediate species. We then examined the influence of CO2 level and ammonium vs. nitrate nutrition on growth, assessed in terms of changes in fresh mass, of several C3 species and a Crassulacean acid metabolism (CAM) species. Elevated CO2 (720 micromol CO2/mol of all gases present) stimulated growth or had no effect in the five C3 species tested when they received ammonium as a nitrogen source but inhibited growth or had no effect if they received nitrate. Under nitrate, two C3 species grew faster at sub-ambient (approximately 310 micromol/mol) than elevated CO2. A CAM species grew faster at ambient than elevated or sub-ambient CO2 under either ammonium or nitrate nutrition. This study establishes that CO2 enrichment inhibits shoot nitrate assimilation in a wide variety of C3 plants and that this phenomenon can have a profound effect on their growth. This indicates that shoot nitrate assimilation provides an important contribution to the nitrate assimilation of an entire C3 plant. Thus, rising CO2 and its effects on shoot nitrate assimilation may influence the distribution of C3 plant species.

  18. Effects of temperature, CO2/O2 concentrations and light intensity on cellular multiplication of microalgae, Euglena gracilis

    Science.gov (United States)

    Kitaya, Y.; Azuma, H.; Kiyota, M.

    2005-01-01

    Microalgae culture is likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO2 to O2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular multiplication of microalgae, Euglena gracilis, was investigated as a fundamental study to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperatures (25-33 degrees C), three levels of CO2 concentrations (2-6%), five levels of O2 concentrations (10-30%), and six levels of photosynthetic photon flux (20-200 micromoles m-2 s-1). The number of Euglena cells in a certain volume of solution was monitored with a microscope under each environmental condition. The multiplication rate of the cells was highest at temperatures of 27-31 degrees C, CO2 concentration of 4%, O2 concentration of 20% and photosynthetic photon flux of about 100 micromoles m-2 s-1. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO2 to O2 under relatively low light intensities in aquatic food production modules. c2005 Published by Elsevier Ltd on behalf of COSPAR.

  19. Effects of temperature, CO 2/O 2 concentrations and light intensity on cellular multiplication of microalgae, Euglena gracilis

    Science.gov (United States)

    Kitaya, Y.; Azuma, H.; Kiyota, M.

    Microalgae culture is likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO 2 to O 2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular multiplication of microalgae, Euglena gracilis, was investigated as a fundamental study to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperatures (25-33 °C), three levels of CO 2 concentrations (2-6%), five levels of O 2 concentrations (10-30%), and six levels of photosynthetic photon flux (20-200 μmol m -2 s -1). The number of Euglena cells in a certain volume of solution was monitored with a microscope under each environmental condition. The multiplication rate of the cells was highest at temperatures of 27-31 °C, CO 2 concentration of 4%, O 2 concentration of 20% and photosynthetic photon flux of about 100 μmol m -2 s -1. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO 2 to O 2 under relatively low light intensities in aquatic food production modules.

  20. The Effect of Seawater CO2 Concentration on Growth of a Natural Phytoplankton Assemblage in a Controlled Mesocosm Experiment

    National Research Council Canada - National Science Library

    Ja-Myung Kim; Kitack Lee; Kyoungsoon Shin; Jung-Hoon Kang; Hyun-Woo Lee; Miok Kim; Pung-Guk Jang; Min-Chul Jang

    2006-01-01

    We examine the effects of seawater pCO2 concentration of 25, 41, and 76 kPa (250, 400, and $750 \\mu atm$) on the growth rate of a natural assemblage of mixed phytoplankton obtained from a carefully controlled, 14-d mesocosm experiment...

  1. Concentrated aqueous piperazine as CO2 capture solvent: detailed evaluation of the integration with a power plant

    NARCIS (Netherlands)

    Ham, L.V. van der; Romano, M.C.; Kvamsdal, H.M.; Bonalumi, D.; Os, P.J. van; Goetheer, E.L.V.

    2014-01-01

    An integrated energetic evaluation has been performed of a reference coal-fired power plant, a power plant with an advanced MEA-based post-combustion CO2 capture plant, and a power plant with a capture plant using concentrated piperazine (PZ) and high-pressure flash regeneration. This comparison

  2. Effects of Changes in Temperature and CO2 Concentration on Simulated Spring Wheat Yields in The Netherlands

    NARCIS (Netherlands)

    Nonhebel, Sanderine

    1993-01-01

    A crop growth simulation model based on SUCROS87 was constructed to study the effects of temperature rise and increase of the atmospheric CO2 concentration on spring wheat yields in The Netherlands. The model simulated potential production (limited by crop characteristics, temperature and radiation

  3. Assessment of aversion to different concentrations of CO2 gas by weaned pigs using an approach-avoidance paradigm

    Science.gov (United States)

    The objective of this study was to examine the aversiveness of carbon dioxide (CO2) to weaned pigs using approach-avoidance and condition place avoidance paradigms. A preference-testing device was custom designed with two connected chambers maintained at static gas concentrations. The control chambe...

  4. Online monitoring of the solvent and absorbed acid gas concentration in a CO2 capture process using monoethanolamine

    NARCIS (Netherlands)

    Eckeveld, A.C. van; Ham, L.V. van der; Geers, L.F.G.; Broeke, L.J.P. van den; Boersma, B.J.; Goetheer, E.L.V.

    2014-01-01

    method has been developed for online liquid analysis of the amine and absorbed CO2 concentrations in a postcombustion capture process using monoethanolamine (MEA) as a solvent. Online monitoring of the dynamic behavior of these parameters is important in process control and is currently achieved

  5. Demonstration of CO2 Conversion to Synthetic Transport Fuel at Flue Gas Concentrations

    Directory of Open Access Journals (Sweden)

    George R. M. Dowson

    2017-10-01

    Full Text Available A mixture of 1- and 2-butanol was produced using a stepwise synthesis starting with a methyl halide. The process included a carbon dioxide utilization step to produce an acetate salt which was then converted to the butanol isomers by Claisen condensation of the esterified acetate followed by hydrogenation of the resulting ethyl acetoacetate. Importantly, the CO2 utilization step uses dry, dilute carbon dioxide (12% CO2 in nitrogen similar to those found in post-combustion flue gases. The work has shown that the Grignard reagent has a slow rate of reaction with oxygen in comparison to carbon dioxide, meaning that the costly purification step usually associated with carbon capture technologies can be omitted using this direct capture-conversion technique. Butanol isomers are useful as direct drop-in replacement fuels for gasoline due to their high octane number, higher energy density, hydrophobicity, and low corrosivity in existing petrol engines. An energy analysis shows the process to be exothermic from methanol to butanol; however, energy is required to regenerate the active magnesium metal from the halide by-product. The methodology is important as it allows electrical energy, which is difficult to store using batteries over long periods of time, to be stored as a liquid fuel that fits entirely with the current liquid fuels infrastructure. This means that renewable, weather-dependent energy can be stored across seasons, for example, production in summer with consumption in winter. It also helps to avoid new fossil carbon entering the supply chain through the utilization of carbon dioxide that would otherwise be emitted. As methanol has also been shown to be commercially produced from CO2, this adds to the prospect of the general decarbonization of the transport fuels sector. Furthermore, as the conversion of CO2 to butanol requires significantly less hydrogen than CO2 to octanes, there is a potentially reduced burden on the so-called hydrogen

  6. Assessment of cultivated and wild, weedy rice lines to concurrent changes in CO2 concentration and air temperature: Determining traits for enhanced seed yield with increasing atmospheric CO2

    Science.gov (United States)

    Although a number of studies have examined intra-specific variability in growth and yield to projected atmospheric CO2 concentration, [CO2], none have compared the relative responses of cultivated and wild, weedy crop lines. We quantified the growth and seed yield response for three cultivated ("44...

  7. Growth CO2 concentration modifies the transpiration response of Populus deltoides to drought and vapor pressure deficit.

    Science.gov (United States)

    Engel, Victor C; Griffin, Kevin L; Murthy, Ramesh; Patterson, Lane; Klimas, Christie; Potosnak, Mark

    2004-10-01

    Cottonwood (Populus deltoides Bartr. ex Marsh.) trees grown for 9 months in elevated carbon dioxide concentration ([CO2]) showed significant increases in height, leaf area and basal diameter relative to trees in a near-ambient [CO2] control treatment. Sample trees in the CO2 treatments were subjected to high and low atmospheric vapor pressure deficits (VPD) over a 5-week period at both high and low soil water contents (SWC). During these periods, transpiration rates at both the leaf and canopy levels were calculated based on sap flow measurements and leaf-to-sapwood area ratios. Leaf-level transpiration rates were approximately equivalent across [CO2] treatments when soil water was not limiting. In contrast, during drought stress, canopy-level transpiration rates were approximately equivalent across [CO2] treatments, indicating that leaf-level fluxes during drought stress were reduced in elevated [CO2] by a factor equal to the leaf area ratio of the two canopies. The shift from equivalent leaf-level transpiration to equivalent canopy-level transpiration with increasing drought stress suggests maximum water use rates were controlled primarily by atmospheric demand at high SWC and by soil water availability at low SWC. Changes in VPD had less effect on transpiration than changes in SWC for trees in both CO2 treatments. Transpiration rates of trees in both CO2 treatments reached maximum values at a VPD of about 2.0 kPa at high SWC, but leveled off and decreased slightly in both canopies as VPD increased above this value. At low SWC, increasing VPD from approximately 1.4 to 2.5 kPa caused transpiration rates to decline slightly in the canopies of trees in both treatments, with significant (P = 0.004) decreases occurring in trees in the near-ambient [CO2] treatment. The transpiration responses at high VPD in the presence of high SWC and throughout the low SWC treatment suggest some hydraulic limitations to water use occurred. Comparisons of midday leaf water potentials

  8. Interactive Effects of CO2 Concentration and Water Regime on Stable Isotope Signatures, Nitrogen Assimilation and Growth in Sweet Pepper

    Science.gov (United States)

    Serret, María D.; Yousfi, Salima; Vicente, Rubén; Piñero, María C.; Otálora-Alcón, Ginés; del Amor, Francisco M.; Araus, José L.

    2018-01-01

    Sweet pepper is among the most widely cultivated horticultural crops in the Mediterranean basin, being frequently grown hydroponically under cover in combination with CO2 fertilization and water conditions ranging from optimal to suboptimal. The aim of this study is to develop a simple model, based on the analysis of plant stable isotopes in their natural abundance, gas exchange traits and N concentration, to assess sweet pepper growth. Plants were grown in a growth chamber for near 6 weeks. Two [CO2] (400 and 800 μmol mol−1), three water regimes (control and mild and moderate water stress) and four genotypes were assayed. For each combination of genotype, [CO2] and water regime five plants were evaluated. Water stress applied caused significant decreases in water potential, net assimilation, stomatal conductance, intercellular to atmospheric [CO2], and significant increases in water use efficiency, leaf chlorophyll content and carbon isotope composition, while the relative water content, the osmotic potential and the content of anthocyanins did change not under stress compared to control conditions support this statement. Nevertheless, water regime affects plant growth via nitrogen assimilation, which is associated with the transpiration stream, particularly at high [CO2], while the lower N concentration caused by rising [CO2] is not associated with stomatal closure. The stable isotope composition of carbon, oxygen, and nitrogen (δ13C, δ18O, and δ15N) in plant matter are affected not only by water regime but also by rising [CO2]. Thus, δ18O increased probably as response to decreases in transpiration, while the increase in δ15N may reflect not only a lower stomatal conductance but a higher nitrogen demand in leaves or shifts in nitrogen metabolism associated with decreases in photorespiration. The way that δ13C explains differences in plant growth across water regimes within a given [CO2], seems to be mediated through its direct relationship with N

  9. Interactive Effects of CO2 Concentration and Water Regime on Stable Isotope Signatures, Nitrogen Assimilation and Growth in Sweet Pepper

    Directory of Open Access Journals (Sweden)

    María D. Serret

    2018-01-01

    Full Text Available Sweet pepper is among the most widely cultivated horticultural crops in the Mediterranean basin, being frequently grown hydroponically under cover in combination with CO2 fertilization and water conditions ranging from optimal to suboptimal. The aim of this study is to develop a simple model, based on the analysis of plant stable isotopes in their natural abundance, gas exchange traits and N concentration, to assess sweet pepper growth. Plants were grown in a growth chamber for near 6 weeks. Two [CO2] (400 and 800 μmol mol−1, three water regimes (control and mild and moderate water stress and four genotypes were assayed. For each combination of genotype, [CO2] and water regime five plants were evaluated. Water stress applied caused significant decreases in water potential, net assimilation, stomatal conductance, intercellular to atmospheric [CO2], and significant increases in water use efficiency, leaf chlorophyll content and carbon isotope composition, while the relative water content, the osmotic potential and the content of anthocyanins did change not under stress compared to control conditions support this statement. Nevertheless, water regime affects plant growth via nitrogen assimilation, which is associated with the transpiration stream, particularly at high [CO2], while the lower N concentration caused by rising [CO2] is not associated with stomatal closure. The stable isotope composition of carbon, oxygen, and nitrogen (δ13C, δ18O, and δ15N in plant matter are affected not only by water regime but also by rising [CO2]. Thus, δ18O increased probably as response to decreases in transpiration, while the increase in δ15N may reflect not only a lower stomatal conductance but a higher nitrogen demand in leaves or shifts in nitrogen metabolism associated with decreases in photorespiration. The way that δ13C explains differences in plant growth across water regimes within a given [CO2], seems to be mediated through its direct

  10. Removal of Low-Molecular Weight Aldehydes by Selected Houseplants under Different Light Intensities and CO2 Concentrations

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-11-01

    Full Text Available The removal of five low-molecular weight aldehydes by two houseplants (Schefflera octophylla (Lour. Harms and Chamaedorea elegans were investigated in a laboratory simulation environment with short-term exposure to different low light intensities and CO2 concentrations. Under normal circumstances, the C1–C5 aldehyde removal rates of Schefflera octophylla (Lour. Harms and Chamaedorea elegans (Lour. Harms ranged from 0.311 μmol/m2/h for valeraldehyde to 0.677 μmol/m2/h for formaldehyde, and 0.526 μmol/m2/h for propionaldehyde to 1.440 μmol/m2/h for formaldehyde, respectively. However, when the light intensities varied from 0 to 600 lx, a significant correlation between the aldehyde removal rate and the light intensity was found. Moreover, the CO2 experiments showed that the total aldehyde removal rates of Schefflera octophylla (Lour. Harms and Chamaedorea elegans (Lour. Harms decreased 32.0% and 43.2%, respectively, with increasing CO2 concentrations from 350 ppmv to 1400 ppmv. This might be explained by the fact that the excessive CO2 concentration decreased the stomatal conductance which limited the carbonyl uptake from the stomata.

  11. Supercritical CO2 extraction of oil and omega-3 concentrate from Sacha inchi (Plukenetia volubilis L. from Antioquia, Colombia

    Directory of Open Access Journals (Sweden)

    D. M. Triana-Maldonado

    2017-03-01

    Full Text Available Sacha inchi (Plukenetia volubilis L. seeds were employed for oil extraction with supercritical CO2 at laboratory scale. The supercritical extraction was carried out at a temperature of 60 °C, pressure range of 400–500 bars and CO2 flow of 40–80 g/min. The maximum recovery was 58% in 180 min, favored by increasing the residence time of CO2 in the extraction tank. Subsequently, the process was evaluated at pilot scale reaching a maximum recovery of 60% in 105 min, with a temperature of 60 °C, pressure of 450 bars and CO2 flow of 1270 g/min. The fatty acid composition of the oil was not affected for an extraction period of 30–120 min. The Sacha inchi oil was fractionated with supercritical CO2 to obtain an omega-3 concentrate oil without finding a considerable increase in the proportion of this compound, due to the narrow range in the carbon number of fatty acids present in the oil (16–18 carbons, making it difficult for selective separation.

  12. Lack of correlation between cerebral vasomotor reactivity and dynamic cerebral autoregulation during stepwise increases in inspired CO2 concentration.

    Science.gov (United States)

    Jeong, Sung-Moon; Kim, Seon-Ok; DeLorey, Darren S; Babb, Tony G; Levine, Benjamin D; Zhang, Rong

    2016-06-15

    Cerebral vasomotor reactivity (CVMR) and dynamic cerebral autoregulation (CA) are measured extensively in clinical and research studies. However, the relationship between these measurements of cerebrovascular function is not well understood. In this study, we measured changes in cerebral blood flow velocity (CBFV) and arterial blood pressure (BP) in response to stepwise increases in inspired CO2 concentrations of 3 and 6% to assess CVMR and dynamic CA in 13 healthy young adults [2 women, 32 ± 9 (SD) yr]. CVMR was assessed as percentage changes in CBFV (CVMRCBFV) or cerebrovascular conductance index (CVCi, CVMRCVCi) in response to hypercapnia. Dynamic CA was estimated by performing transfer function analysis between spontaneous oscillations in BP and CBFV. Steady-state CBFV and CVCi both increased exponentially during hypercapnia; CVMRCBFV and CVMRCVCi were greater at 6% (3.85 ± 0.90 and 2.45 ± 0.79%/mmHg) than at 3% CO2 (2.09 ± 1.47 and 0.21 ± 1.56%/mmHg, P = 0.009 and 0.005, respectively). Furthermore, CVMRCBFV was greater than CVMRCVCi during either 3 or 6% CO2 (P = 0.017 and P < 0.001, respectively). Transfer function gain and coherence increased in the very low frequency range (0.02-0.07 Hz), and phase decreased in the low-frequency range (0.07-0.20 Hz) when breathing 6%, but not 3% CO2 There were no correlations between the measurements of CVMR and dynamic CA. These findings demonstrated influences of inspired CO2 concentrations on assessment of CVMR and dynamic CA. The lack of correlation between CVMR and dynamic CA suggests that cerebrovascular responses to changes in arterial CO2 and BP are mediated by distinct regulatory mechanisms. Copyright © 2016 the American Physiological Society.

  13. Effects of CO2 Concentration on Leaf Photosynthesis and Stomatal Conductance of Potatoes Grown Under Different Irradiance Levels and Photoperiods

    Science.gov (United States)

    Wheeler, R. M.; Fitzpatrick, A. H.; Tibbitts, T. W.

    2012-01-01

    Potato (Solanum tuberosum L.) cvs. Russet Burbank, Denali, and Norland, were grown in environmental rooms controlled at approx 350 micro mol/mol (ambient during years 1987/1988) and 1000 micro mol/mol (enriched) CO2 concentrations. Plants and electric lamps were arranged to provide two irradiance zones, 400 and 800 micro mol/mol/square m/S PPF and studies were repeated using two photoperiods (12-h light / 12-h dark and continuous light). Leaf photosynthetic rates and leaf stomatal conductance were measured using fully expanded, upper canopy leaves at weekly intervals throughout growth (21 through 84 days after transplanting). Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod increased leaf photosynthetic rates by 39% at 400 micro mol/mol/square m/S PPF and 27% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under continuous light decreased leaf photosynthetic rates by 7% at 400 micro mol/mol/square m/S PPF and 13% at 800 micro mol/mol/square m/S PPF. Increasing the CO2 from approx 350 to 1000 micro mol/mol under the 12-h photoperiod plants decreased stomatal conductance by an average of 26% at 400 micro mol/mol/square m/S PPF and 42% at 800 micro mol/mol/square m/S PPF. Under continuous light, CO2 enrichment resulted in a small increase (2%) of stomatal conductance at 400 micro mol/mol/square m/S PPF, and a small decrease (3%) at 800 micro mol/mol/square m/S PPF. Results indicate that CO2 enrichment under the 12-h photoperiod showed the expected increase in photosynthesis and decrease in stomatal conductance for a C3 species like potato, but the decreases in leaf photosynthetic rates and minimal effect on conductance from CO2 enrichment under continuous light were not expected. The plant leaves under continuous light showed more chlorosis and some rusty flecking versus plants under the 12-h photoperiod, suggesting the continuous light was more stressful on the plants. The increased

  14. Direct Detection 1.6?m DIAL / Doppler Lidar for Measurements of CO2 Concentration and Wind Profiles (Invited)

    Science.gov (United States)

    Shibata, Y.; Nagasawa, C.; Abo, M.

    2013-12-01

    Knowledge of present carbon sources and sinks including their spatial distribution and their variation in time is one of the essential information for predicting future CO2 atmospheric concentration levels. Moreover, wind information is an important parameter for transport simulations and inverse estimation of surface CO2 flux. The differential absorption lidar (DIAL) and the Doppler wind lidar with the range resolution is expected to measure atmospheric CO2 profiles and wind profiles in the atmospheric boundary layer and lower troposphere from a ground platform. We have succeeded to develop a scanning 1.6 μm DIAL and incoherent Doppler lidar system for simultaneously measuring CO2 concentration and wind speed profiles. Our 1.6 μm DIAL system consists of the Optical Parametric Generator (OPG) transmitter that excited by the LD pumped Nd: YAG laser with high repetition rate (500 Hz) and the receiving optics that included the near-infrared photomultiplier tube with high quantum efficiency operating at the photon counting mode, a fiber Bragg grating (FBG) filter to detect a Doppler shift, and a 25 cm telescope [1] [2]. We had developed an optical parametric oscillator (OPO) system for 1.6 μm CO2 DIAL[3]. To achieve continuous tuning of the resonant OPO output without mode hopping, it is necessary to vary the OPO cavity length synchronously with the seed-frequency. On the other hand, the OPG does not require a cavity and instead rely on sufficient conversion efficiency to be obtained with a single pass through the crystal. The single-frequency oscillation of the OPG was achieved by injection seeding. The CO2-DIAL was operated with the range-height indicator (RHI) mode, and the 2-D measurement provided inhomogeneity in the boundary layer. Vertical CO2 concentration profiles and wind profiles were also measured simultaneously. The elevation angle was fixed at 52 deg and CO2 concentration profiles were obtained up to 1 km altitude with 200 m height resolution. Vertical

  15. Changing Amazon biomass and the role of atmospheric CO2 concentration, climate, and land use

    Science.gov (United States)

    de Almeida Castanho, Andrea D.; Galbraith, David; Zhang, Ke; Coe, Michael T.; Costa, Marcos H.; Moorcroft, Paul

    2016-01-01

    The Amazon tropical evergreen forest is an important component of the global carbon budget. Its forest floristic composition, structure, and function are sensitive to changes in climate, atmospheric composition, and land use. In this study biomass and productivity simulated by three dynamic global vegetation models (Integrated Biosphere Simulator, Ecosystem Demography Biosphere Model, and Joint UK Land Environment Simulator) for the period 1970-2008 are compared with observations from forest plots (Rede Amazónica de Inventarios Forestales). The spatial variability in biomass and productivity simulated by the DGVMs is low in comparison to the field observations in part because of poor representation of the heterogeneity of vegetation traits within the models. We find that over the last four decades the CO2 fertilization effect dominates a long-term increase in simulated biomass in undisturbed Amazonian forests, while land use change in the south and southeastern Amazonia dominates a reduction in Amazon aboveground biomass, of similar magnitude to the CO2 biomass gain. Climate extremes exert a strong effect on the observed biomass on short time scales, but the models are incapable of reproducing the observed impacts of extreme drought on forest biomass. We find that future improvements in the accuracy of DGVM predictions will require improved representation of four key elements: (1) spatially variable plant traits, (2) soil and nutrients mediated processes, (3) extreme event mortality, and (4) sensitivity to climatic variability. Finally, continued long-term observations and ecosystem-scale experiments (e.g. Free-Air CO2 Enrichment experiments) are essential for a better understanding of the changing dynamics of tropical forests.

  16. Active microbial community in gas reservoirs in the North German Plain and the effects of high CO2 concentrations

    Science.gov (United States)

    Frerichs, Janin; Gniese, Claudia; Mühling, Martin; Krüger, Martin

    2010-05-01

    From the IPCC report on global warming, it is clear that large-scale solutions are needed immediately to reduce emissions of greenhouse gases. The CO2 capture and storage offers one option for reducing the greenhouse gas emissions. Favourable CO2 storage sites are depleted gas and oil fields and thus, are currently investigated by the BMBF-Geotechnologien RECOBIO-2 project. Our study is focussing on the direct influence of high CO2 concentrations on the autochthonous microbial population and environmental parameters (e.g. availability of nutrients). The gas fields Schneeren in the 'North German Plain' is operated by Gaz de France SUEZ E&V Deutschland GmbH. The conditions in the reservoir formation waters of two bore wells differ in various geochemical parameters (pH, salinity and temperature). In previous studies the community of this gas field was described by Ehinger et al. 2009. Based on these results our study included cultivation and molecular biological approaches. Our results showed significant differences of the community structure in regional distinctions of the gas reservoir. The activity profiles of two wells differed clearly in the inducible activity after substrate addition. The fluids of well A showed a high methane production rate after the addition of methanol or acetate. Well B showed a high sulphide production after the addition of sulphate and hydrogen. The molecular biological analysis of the original fluids supports the activity profile for both sites. The community analysis via real-time PCR showed for the production well head A a higher abundances for Archaea than for B. The community at site B in contrast was dominated by Bacteria. Fluids of both wells were also incubated with high CO2 concentrations in the headspace. These enrichments showed a significant decrease of methane and sulphide production with increasing CO2 levels. Currently, the community composition is analysed to identify changes connected to increased CO2 concentrations. This

  17. The Form in Which Nitrogen Is Supplied Affects the Polyamines, Amino Acids, and Mineral Composition of Sweet Pepper Fruit under an Elevated CO2 Concentration.

    Science.gov (United States)

    Piñero, Maria C; Otálora, Ginés; Porras, Manuel E; Sánchez-Guerrero, Mari C; Lorenzo, Pilar; Medrano, Evangelina; Del Amor, Francisco M

    2017-02-01

    We investigated the effect of supplying nitrogen, as NO3(-) or as NO3(-)/NH4(+), on the composition of fruits of sweet pepper (Capsicum annuum L. cv. Melchor) plants grown with different CO2 concentrations ([CO2]): ambient or elevated (800 μmol mol(-1)). The results show that the application of NH4(+) and high [CO2] affected the chroma related to the concentrations of chlorophylls. The concentrations of Ca, Cu, Mg, P, and Zn were significantly reduced in the fruits of plants nourished with NH4(+), the loss of Fe being more dramatic at increased [CO2], which was also the case with the protein concentration. The concentration of total phenolics was increased by NH4(+), being unaffected by [CO2]. Globally, the NH4(+) was the main factor that affected fruit free amino acid concentrations. Polyamines were affected differently: putrescine was increased by elevated [CO2], while the response of cadaverine depended on the form of N supplied.

  18. Atmospheric CO2 level affects plants' carbon use efficiency: insights from a 13C labeling experiment on sunflower stands

    Science.gov (United States)

    Gong, Xiaoying; Schäufele, Rudi; Schnyder, Hans

    2015-04-01

    The increase of atmospheric CO2 concentration has been shown to stimulate plant photosynthesis and (to a lesser extent) growth, thereby acting as a possible sink for the additional atmospheric CO2. However, this effect is dependent on the efficiency with which plants convert atmospheric carbon into biomass carbon, since a considerable proportion of assimilated carbon is returned to the atmosphere via plant respiration. As a core parameter for carbon cycling, carbon use efficiency of plants (CUE, the ratio of net primary production to gross primary production) quantifies the proportion of assimilated carbon that is incorporated into plant biomass. CUE has rarely been assessed based on measurements of complete carbon balance, due to methodological difficulties in measuring respiration rate of plants in light. Moreover, foliar respiration is known to be inhibited in light, thus foliar respiration rate is generally lower in light than in dark. However, this phenomenon, termed as inhibition of respiration in light (IRL), has rarely been assessed at the stand-scale and been incorporated into the calculation of CUE. Therefore, how CUE responses to atmospheric CO2 levels is still not clear. We studied CUE of sunflower stands grown at sub-ambient CO2 level (200 μmol mol-1) and elevated CO2 level (1000 μmol mol-1) using mesocosm-scale gas exchange facilities which enabled continuous measurements of 13CO2/12CO2 exchange. Appling steady-state 13C labeling, fluxes of respiration and photosynthesis in light were separated, and tracer kinetic in respiration was analyzed. This study provides the first data on CUE at a mesocosm-level including respiration in light in different CO2 environments. We found that CUE of sunflower was lower at an elevated CO2 level than at a sub-ambient CO2 level; and the ignorance of IRL lead to erroneous estimations of CUE. Variation in CUE at atmospheric CO2 levels was attributed to several mechanisms. In this study, CO2 enrichment i) affected the

  19. Dependence of MgGa2O4:Co2+ photoluminescence on temperature and impurity concentration

    Science.gov (United States)

    Sosman, L. P.; Dias Tavares, A., Jr.; da Fonseca, R. J. M.; Papa, A. R. R.

    2008-10-01

    Polycrystalline samples of MgGa2O4 doped with 0.1 and 1.0% of Co2+ ions were produced by ceramic methods and investigated by x-ray diffraction and luminescence spectroscopy. Emission data at room temperature and 77 K, as well as transition lifetimes obtained by the phase-shift method, are presented. The emission is attributed to ^{4} {T}_{1}({}^{4} {P}) \\to {}^{4} {A_{2}({}{}^{4} {F})} of Co2+ ions in tetrahedral sites. The excitation spectra are associated with ^{4} {A}_{2}({}^{4} {F}) \\to {}^{2} {A}_{1}(^{2} {G}) , ^{4} {A}_{2}({}^{4} {F}) \\to {}^{2} {E}(^{2} {G}) and ^{4} {A}_{2}({}^{4} {F}) \\to {}^{4} {T}_{1}({}^{4} {P}) electronic transitions. The crystal field Dq and Racah parameter B were obtained from the spectra and Tanabe-Sugano energy level diagram. The highlights of the present work are the relatively simple sample obtention process as well as its reproducibility and the high photoluminescence quantum efficiency (near to 1.0) together with the intense and broad emission band which make the MgGa2O4 a very attractive material for use as tunable media.

  20. Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

    Science.gov (United States)

    Kromdijk, Johannes; Ubierna, Nerea; Cousins, Asaph B; Griffiths, Howard

    2014-07-01

    Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

  1. Concentration of phenolic compounds is increased in lettuce grown under high light intensity and elevated CO2.

    Science.gov (United States)

    Pérez-López, Usue; Sgherri, Cristina; Miranda-Apodaca, Jon; Micaelli, Francesco; Lacuesta, Maite; Mena-Petite, Amaia; Quartacci, Mike Frank; Muñoz-Rueda, Alberto

    2018-02-01

    The present study was focused on lettuce, a widely consumed leafy vegetable for the large number of healthy phenolic compounds. Two differently-pigmented lettuce cultivars, i.e. an acyanic-green leaf cv. and an anthocyanic-red one, were grown under high light intensity or elevated CO2 or both in order to evaluate how environmental conditions may affect the production of secondary phenolic metabolites and, thus, lettuce quality. Mild light stress imposed for a short time under ambient or elevated CO2 concentration increased phenolics compounds as well as antioxidant capacity in both lettuce cvs, indicating how the cultivation practice could enhance the health-promoting benefits of lettuce. The phenolic profile depended on pigmentation and the anthocyanic-red cv. always maintained a higher phenolic amount as well as antioxidant capacity than the acyanic-green one. In particular, quercetin, quercetin-3-O-glucuronide, kaempferol, quercitrin and rutin accumulated under high light or high CO2 in the anthocyanic-red cv., whereas cyanidin derivatives were responsive to mild light stress, both at ambient and elevated CO2. In both cvs total free and conjugated phenolic acids maintained higher values under all altered environmental conditions, whereas luteolin reached significant amounts when both stresses were administered together, indicating, in this last case, that the enzymatic regulation of the flavonoid synthesis could be differently affected, the synthesis of flavones being favored. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. The Kok effect in Vicia faba cannot be explained solely by changes in chloroplastic CO2 concentration.

    Science.gov (United States)

    Buckley, Thomas N; Vice, Heather; Adams, Mark A

    2017-08-31

    The Kok effect - an abrupt decline in quantum yield (QY) of net CO2 assimilation at low photosynthetic photon flux density (PPFD) - is widely used to estimate respiration in the light (R), which assumes the effect is caused by light suppression of R. A recent report suggested much of the Kok effect can be explained by declining chloroplastic CO2 concentration (cc ) at low PPFD. Several predictions arise from the hypothesis that the Kok effect is caused by declining cc , and we tested these predictions in Vicia faba. We measured CO2 exchange at low PPFD, in 2% and 21% oxygen, in developing and mature leaves, which differed greatly in R in darkness. Our results contradicted each of the predictions based on the cc effect: QY exceeded the theoretical maximum value for photosynthetic CO2 uptake; QY was larger in 21% than 2% oxygen; and the change in QY at the Kok effect breakpoint was unaffected by oxygen. Our results strongly suggest the Kok effect arises largely from a progressive decline in R with PPFD that includes both oxygen-sensitive and -insensitive components. We suggest an improved Kok method that accounts for high cc at low PPFD. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  3. Serum protein and casein concentration: effect on pH and freezing point of milk with added CO2.

    Science.gov (United States)

    Ma, Y; Barbano, D M

    2003-05-01

    The objective of this study was to determine the effect of protein concentration and protein type [i.e., casein (CN) and serum protein (SP)] on pH (0 degree C) and freezing point (FP) of skim milk upon CO2 injection at 0 degree C. CN-free skim milks with increasing SP content (0, 3, and 6%) and skim milks with the same SP content (0.6%) but increasing CN content (2.4, 4.8, and 7.2%) were prepared using a combination of microfiltration and ultrafiltration processes. CO2 was injected into milks at 0 degree C using a continuous flow carbonation unit (230 ml/min). Increasing SP or CN increased milk buffering capacity and protein-bound mineral content. At the same CO2 concentration at 0 degree C, a milk with a higher SP or a higher CN concentration had more resistance to pH change and a greater extent of FP decrease. The buffering capacity provided by an increase of CN was contributed by both the CN itself and the colloidal salts solublized into the serum phase from CN upon carbonation. Skim milks with the same true protein content (3%), one with 2.4% CN plus 0.6% SP and one with 3% SP, were compared. At the same true protein content (3%), increasing the proportion of CN increased milk buffering capacity and protein-bound mineral content. Milk with a higher proportion of CN had more resistance to pH change and a greater extent of FP decrease at the same carbonation level at 0 degree C. Once CO2 was dissolved in the skim portion of a milk, the extent of pH reduction and FP depression depended on protein concentration and protein type (i.e., CN and SP).

  4. The effect of increased atmospheric temperature and CO2 concentration during crop growth on the chemical composition and in vitro rumen fermentation characteristics of wheat straw.

    Science.gov (United States)

    He, Xiangyu; Wu, Yanping; Cai, Min; Mu, Chunlong; Luo, Weihong; Cheng, Yanfen; Zhu, Weiyun

    2015-01-01

    This experiment was conducted to investigate the effects of increased atmospheric temperature and CO2 concentration during crop growth on the chemical composition and in vitro rumen fermentation characteristics of wheat straw. The field experiment was carried out from November 2012 to June 2013 at Changshu (31°32'93″N, 120°41'88″E) agro-ecological experimental station. A total of three treatments were set. The concentration of CO2 was increased to 500 μmol/mol in the first treatment (CO2 group). The temperature was increased by 2 °C in the second treatment (TEM group) and the concentration of CO2 and temperature were both increased in the third treatment (CO2 + TEM group). The mean temperature and concentration of CO2 in control group were 10.5 °C and 413 μmol/mol. At harvesting, the wheat straws were collected and analyzed for chemical composition and in vitro digestibility. Results showed that dry matter was significantly increased in all three treatments. Ether extracts and neutral detergent fiber were significantly increased in TEM and CO2 + TEM groups. Crude protein was significantly decreased in CO2 + TEM group. In vitro digestibility analysis of wheat straw revealed that gas production was significantly decreased in CO2 and CO2 + TEM groups. Methane production was significantly decreased in TEM and CO2 + TEM groups. Ammonia nitrogen and microbial crude protein were significantly decreased in all three treatments. Total volatile fatty acids were significantly decreased in CO2 and CO2 + TEM groups. In conclusion, the chemical composition of the wheat straw was affected by temperature and CO2 and the in vitro digestibility of wheat straw was reduced, especially in the combined treatment of temperature and CO2.

  5. MULTISENSOR MICROSYSTEM FOR MEASURING THE CONCENTRATION OF GASES CO, H2 , C3 H8 , CO2

    Directory of Open Access Journals (Sweden)

    O. G. Reutskaya

    2016-01-01

    Full Text Available Manufacture of module of chemical sensors on a single chip is one of the promising directions in the development of gas sensory. The aim of this work was development of construction of multisensor microsystem enabled to retain the characteristics of a single sensor and its dimensions and, at the same time, to reduce power consumption and cycle time of measuring concentration of gases CO, H2 , C3H8 , CO2 in the environment. Multisensor microsystem consists of four detached sensors placed on a single substrate of nanostructured aluminum oxide. The use of through-holes and the dielectric substrate itself in microsystem topology reduced power consumption of gas microsystems. We have devised a method of measuring sensitivity of foursensor microsystem to the concentration of gases CO, H2 , C3H8 , CO2. A full cycle of measuring gases concentration consisted of the time required for preliminary heating of all sensors of the microsystem (5 s, the heating time of each of the sensors sequentially (5 s and time required to measure resistance for each sensor (80 s. The measured results show that the reaction time of multisensor microsystem when exposed to gases – H2 at a concentration of 0,001 %, CO2  1 %, СО – 0,02 %, C3H8 – 0,01 % does not exceed 90 s for full measurement cycle. Sensitivity value at power consumption of < 150 mW makes up 48–64 % for H2 , 32– 36 % for CO2 , 20–29 % for СО, 68–78 % for C3H8 . The proposed method to control sensitivity of multisensor microsystem to the concentration of gases CO, H2 , C3H8 , CO2 allows performing measurements within 90 s while the measurement cycle by a single sensor in pulse heating mode is 2 min, in continuous heat mode – 5 min. Maximum power consumption of the microsystem does not exceed 150 mW. Microsystems allow measuring lower concentrations of detected gases. 

  6. Transcriptome and key genes expression related to carbon fixation pathways in Chlorella PY-ZU1 cells and their growth under high concentrations of CO2.

    Science.gov (United States)

    Huang, Yun; Cheng, Jun; Lu, Hongxiang; He, Yong; Zhou, Junhu; Cen, Kefa

    2017-01-01

    The biomass yield of Chlorella PY-ZU1 drastically increased when cultivated under high CO2 condition compared with that cultivated under air condition. However, less attention has been given to the microalgae photosynthetic mechanisms response to different CO2 concentrations. The genetic reasons for the higher growth rate, CO2 fixation rate, and photosynthetic efficiency of microalgal cells under higher CO2 concentration have not been clearly defined yet. In this study, the Illumina sequencing and de novo transcriptome assembly of Chlorella PY-ZU1 cells cultivated under 15% CO2 were performed and compared with those of cells grown under air. It was found that carbonic anhydrase (CAs, enzyme for interconversion of bicarbonate to CO2) dramatically decreased to near 0 in 15% CO2-grown cells, which indicated that CO2 molecules directly permeated into cells under high CO2 stress without CO2-concentrating mechanism. Extrapolating from the growth conditions and quantitative Real-Time PCR of CCM-related genes, the Km (CO2) (the minimum intracellular CO2 concentration that rubisco required) of Chlorella PY-ZU1 might be in the range of 80-192 μM. More adenosine triphosphates was saved for carbon fixation-related pathways. The transcript abundance of rubisco (the most important enzyme of CO2 fixation reaction) was 16.3 times higher in 15% CO2-grown cells than that under air. Besides, the transcript abundances of most key genes involved in carbon fixation pathways were also enhanced in 15% CO2-grown cells. Carbon fixation and nitrogen metabolism are the two most important metabolisms in the photosynthetic cells. These genes related to the two most metabolisms with significantly differential expressions were beneficial for microalgal growth (2.85 g L(-1)) under 15% CO2 concentration. Considering the micro and macro growth phenomena of Chlorella PY-ZU1 under different concentrations of CO2 (0.04-60%), CO2 transport pathways responses to different CO2 (0

  7. Enzyme activity highlights the importance of the oxidative pentose phosphate pathway in lipid accumulation and growth of Phaeodactylum tricornutum under CO2 concentration.

    Science.gov (United States)

    Wu, Songcui; Huang, Aiyou; Zhang, Baoyu; Huan, Li; Zhao, Peipei; Lin, Apeng; Wang, Guangce

    2015-01-01

    Rising CO2 concentration was reported to increase phytoplankton growth rate as well as lipid productivity. This has raised questions regarding the NADPH supply for high lipid synthesis as well as rapid growth of algal cells. In this study, growth, lipid content, photosynthetic performance, the activity, and expression of key enzymes in Calvin cycle and oxidative pentose phosphate pathway (OPPP) were analyzed in the marine diatom Phaeodactylum tricornutum under three different CO2 concentrations (low CO2 (0.015 %), mid CO2 (atmospheric, 0.035 %) and high CO2 (0.15 %)). Both the growth rate and lipid content of P. tricornutum increased significantly under the high CO2 concentration. Enzyme activity and mRNA expression of three Calvin cycle-related enzymes (Rubisco, 3-phosphoglyceric phosphokinase (PGK), phosphoribulokinase (PRK)) were also increased under high CO2 cultivation, which suggested the enhancement of Calvin cycle activity. This may account for the observed rapid growth rate. In addition, high activity and mRNA expression of G6PDH and 6PGDH, which produce NADPH through OPPP, were observed in high CO2 cultured cells. These results indicate OPPP was enhanced and might play an important role in lipid synthesis under high CO2 concentration. The oxidative pentose phosphate pathway may participate in the lipid accumulation in rapid-growth P. tricornutum cells in high CO2 concentration.

  8. CO2-induced photosynthetic and stoichiometric responses to phosphorus limitation

    Science.gov (United States)

    de Boer, Hugo; di Lallo, Giacomo; van Dijk, Jerry

    2017-04-01

    Carbon fertilisation from rising atmospheric CO2 concentrations increases the productivity of plants globally. Meanwhile, the global cycles of Nitrogen (N) and Phosphorus (P) are also altered due to anthropogenic emissions. In general, the additional supply of N is expected to exceed that of P, leading to an increase in P limitation in natural ecosystems. Although the direct carbon fertilisation effect and the interaction with available N is relatively well understood, it remains uncertain how carbon fertilisation is confounded by the availability of P. It is hypothesised that (i) the photosynthetic P-use efficiency increases at elevated CO2 owing to a direct increase in photosynthesis and (ii) the photosynthetic maximum carboxylation rate (Vcmax) and electron transport rate (Jmax) are down-regulated in response to a combination of elevated CO2 and P-limitation via a coordinated reduction of leaf N and P content per unit leaf area. In this study we examined the hypothesised effects of P limitation and CO2 fertilisation on the photosynthetic and stoichiometric responses of three plant species: Holcus lanatus (C3 grass), Panicum miliaceum (C4 grass) and Solanum dulcamara (C3 herb). Individuals of these species were grown at sub-ambient (150 ppm), modern (450 ppm) and elevated CO2 concentrations (800 ppm) and exposed to an N:P treatment consisting of either severe nitrogen limitation at an N:P ratio of 1:1, or severe P limitation at an N:P ratio of 45:1, with a similar supply rate of N. Our results show significant effects of growth CO2 and P supply on Vcmax and Jmax, as well as the whole-plant biomass at the point of harvest. Interaction effects between growth CO2 and P supply were observed for the light-saturated photosynthesis rate, stomatal conductance, leaf P content, and the N:P ratio of the leaf. No significant change in the leaf N content was observed across treatments. These results suggest that limited availability of P constrains the biochemical potential

  9. [Direct Observation on the Temporal and Spatial Patterns of the CO2 Concentration in the Atmospheric of Nanjing Urban Canyon in Summer].

    Science.gov (United States)

    Gao, Yun-qiu; Liu, Shou-dong; Hu, Ning; Wang, Shu-min; Deng, Li-chen; Yu, Zhou; Zhang, Zhen; Li, Xu-hui

    2015-07-01

    Direct observation of urban atmospheric CO2 concentration is vital for the research in the contribution of anthropogenic activity to the atmospheric abundance since cities are important CO2 sources. The observations of the atmospheric CO2 concentration at multiple sites/heights can help us learn more about the temporal and spatial patterns and influencing mechanisms. In this study, the CO2 concentration was observed at 5 sites (east, west, south, north and middle) in the main city area of Nanjing from July 18 to 25, 2014, and the vertical profile of atmospheric CO2 concentration was measured in the middle site at 3 heights (30 m, 65 m and 110 m). The results indicated that: (1) An obvious vertical CO2 gradient was found, with higher CO2 concentration [molar fraction of 427. 3 x 10(-6) (±18. 2 x 10(-6))] in the lower layer due to the strong influences of anthropogenic emissions, and lower CO2 concentration in the upper layers [411. 8 x 10(-6) (±15. 0 x 10(-6)) and 410. 9 x 10(-6) (±14. 6 x 10(-6)) at 65 and 110 m respectively] for the well-mixed condition. The CO2 concentration was higher and the vertical gradient was larger when the atmosphere was stable. (2) The spatial distribution pattern of CO2 concentration was dominated by wind and atmospheric stability. During the observation, the CO2 concentration in the southwest was higher than that in the northeast region with the CO2 concentration difference of 7. 8 x 10(-6), because the northwest wind was prevalent. And the CO2 concentration difference reduced with increasing wind speed since stronger wind diluted CO2 more efficiently. The more stable the atmosphere was, the higher the CO2 concentration was. (3) An obvious diurnal variation of CO2 concentration was shown in the 5 sites. A peak value occurred during the morning rush hours, the valley value occurred around 17:00 (Local time) and another high value occurred around 19:00 because of evening rush hour sometimes.

  10. High CO2 concentration increases relative leaf carbon gain under dynamic light in Dipterocarpus sublamellatus seedlings in a tropical rain forest, Malaysia.

    Science.gov (United States)

    Tomimatsu, Hajime; Iio, Atsuhiro; Adachi, Minaco; Saw, Leng-Guan; Fletcher, Christine; Tang, Yanhong

    2014-09-01

    Understory plants in tropical forests often experience a low-light environment combined with high CO2 concentration. We hypothesized that the high CO2 concentration may compensate for leaf carbon loss caused by the low light, through increasing light-use efficiency of both steady-state and dynamic photosynthetic properties. To test the hypothesis, we examined CO2 gas exchange in response to an artificial lightfleck in Dipterocarpus sublamellatus Foxw. seedlings under contrasting CO2 conditions: 350 and 700 μmol CO2 mol(-1) air in a tropical rain forest, Pasoh, Malaysia. Total photosynthetic carbon gain from the lightfleck was about double when subjected to the high CO2 when compared with the low CO2 concentration. The increase of light-use efficiency in dynamic photosynthesis contributed 7% of the increased carbon gain, most of which was due to reduction of photosynthetic induction to light increase under the high CO2. The light compensation point of photosynthesis decreased by 58% and the apparent quantum yield increased by 26% at the high CO2 compared with those at the low CO2. The study suggests that high CO2 increases photosynthetic light-use efficiency under both steady-state and fluctuating light conditions, which should be considered in assessing the leaf carbon gain of understory plants in low-light environments. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Partitioning of photosynthetic electron flow between CO2 and O 2 reduction in a C 3 leaf (Phaseolus vulgaris L.) at different CO 2 concentrations and during drought stress.

    Science.gov (United States)

    Cornic, G; Briantais, J M

    1991-01-01

    Photosystem II chlorophyll fluorescence and leaf net gas exchanges (CO2 and H2O) were measured simultaneously on bean leaves (Phaseolus vulgaris L.) submitted either to different ambient CO2 concentrations or to a drought stress. When leaves are under photorespiratory conditions, a simple fluorescence parameter ΔF/ Fm (B. Genty et al. 1989, Biochem. Biophys. Acta 990, 87-92; ΔF = difference between maximum, Fm, and steady-state fluorescence emissions) allows the calculation of the total rate of photosynthetic electron-transport and the rate of electron transport to O2. These rates are in agreement with the measurements of leaf O2 absorption using (18)O2 and the kinetic properties of ribulose-1,5bisphosphate carboxylase/oxygenase. The fluorescence parameter, ΔF/Fm, showed that the allocation of photosynthetic electrons to O2 was increased during the desiccation of a leaf. Decreasing leaf net CO2 uptake, either by decreasing the ambient CO2 concentration or by dehydrating a leaf, had the same effect on the partitioning of photosynthetic electrons between CO2 and O2 reduction. It is concluded that the decline of net CO2 uptake of a leaf under drought stress is only due, at least for a mild reversible stress (causing at most a leaf water deficit of 35%), to stomatal closure which leads to a decrease in leaf internal CO2 concentration. Since, during the dehydration of a leaf, the calculated internal CO2 concentration remained constant or even increased we conclude that this calculation is misleading under such conditions.

  12. Will C3 crops enhanced with the C4 CO2-concentrating mechanism live up to their full potential (yield)?

    Science.gov (United States)

    Driever, Steven M; Kromdijk, Johannes

    2013-10-01

    Sustainably feeding the world's growing population in future is a great challenge and can be achieved only by increasing yield per unit land surface. Efficiency of light interception and biomass partitioning into harvestable parts (harvest index) has been improved substantially via plant breeding in modern crops. The conversion efficiency of intercepted light into biomass still holds promise for yield increase. This conversion efficiency is to a great extent constrained by the metabolic capacity of photosynthesis, defined by the characteristics of its components. Genetic manipulations are increasingly applied to lift these constraints, by improving CO2 or substrate availability for the photosynthetic carbon reduction cycle. Although these manipulations can lead to improved potential growth rates, this increase might be offset by a decrease in performance under stress conditions. In this review, we assess possible positive or negative effects of the introduction of a CO2-concentrating mechanism in C3 crop species on crop potential productivity and yield robustness.

  13. Positive feedback between global warming and atmospheric CO2 concentration inferred from past climate change

    Science.gov (United States)

    Scheffer, Marten; Brovkin, Victor; Cox, Peter M.

    2006-05-01

    There is good evidence that higher global temperatures will promote a rise of greenhouse gas levels, implying a positive feedback which will increase the effect of anthropogenic emissions on global temperatures. However, the magnitude of this effect predicted by the available models remains highly uncertain, due to the accumulation of uncertainties in the processes thought to be involved. Here we present an alternative way of estimating the magnitude of the feedback effect based on reconstructed past changes. Linking this information with the mid-range Intergovernmental Panel on Climate Change estimation of the greenhouse gas effect on temperature we suggest that the feedback of global temperature on atmospheric CO2 will promote warming by an extra 15-78% on a century-scale. This estimate may be conservative as we did not account for synergistic effects of likely temperature moderated increase in other greenhouse gases. Our semi-empirical approach independently supports process based simulations suggesting that feedback may cause a considerable boost in warming.

  14. Sensitivity of plants to changing atmospheric CO2 concentration: From the geological past to the next century

    Energy Technology Data Exchange (ETDEWEB)

    Franks, Peter J [University of Sydney, Australia; Adams, Mark A [University of Sydney, Australia; Amthor, Jeffrey S. [U.S. Department of Energy; Barbour, Margaret M [University of Sydney, Australia; Berry, Joseph A [Carnegie Institution of Washington; Ellsworth, David [ORNL; Farquhar, Graham D [Australian National University, Canberra, Australia; Ghannoum, Oula [University of Western Sydney, Australia; Lloyd, Jon [James Cook University; McDowell, Nathan [ORNL; Norby, Richard J [ORNL; Tissue, David Thomas [ORNL; Von Caemmerer, Susanne [Australian National University, Canberra, Australia

    2013-01-01

    The rate of CO2 assimilation by plants is directly influenced by the concentration of CO2 in the atmosphere, ca. In response to a short-term change in ca, plants adjust stomatal conductance to CO2 and water vapour to maximise carbon gain in terms of the amount of water lost. This is one of several fundamental feedback processes between plants and their environment that govern the exchange of water for carbon. As an environmental variable, ca further has a unique global and historic significance. Although relatively stable and uniform in the short term, global ca has varied substantially on the timescale of thousands to millions of years, and currently is increasing at seemingly an unprecedented rate. This may exert profound impacts on both climate and plant function. Here we utilise extensive data sets and numerous models to develop an integrated, multi-scale assessment of the impact of changing ca on plant carbon dioxide uptake and water use. We find that, overall, the sensitivity of plants to rising or falling atmospheric CO2 concentration is qualitatively similar across all scales considered. It is characterised by an adaptive feedback response that moves towards maximising the rate of return, in the form of carbon, for the water and nitrogen resources invested in the process of carbon assimilation. This is achieved through predictable adjustments to stomatal anatomy and chloroplast biochemistry. Importantly, the long-term response to changing ca can be described by simple equations rooted in the formulation of more commonly studied short-term responses.

  15. The Influence of Climate Change on CO2 and CH4 Concentration Near Closed Shaft - Numerical Simulations

    Science.gov (United States)

    Wrona, Paweł

    2017-09-01

    Given the scientific consensus pointing to climate change, the more extreme weather events associated with this will lead to deeper pressure drops. As has already been stated, pressure drops are the main cause of gas flow from underground sites to the surface. This article presents the results of numerical simulations of the change in distribution of CO2 and CH4 near a closed mining shaft under the predicted baric tendency. Simulations have been undertaken by means of the FDS software package with the Pyrosim graphical interface - a CFD tool for fire and ventilation analysis. Assumptions have been based on previous results of in-situ measurements. The results (determined for a height of 1m above the ground) were compared to the following levels (later in the text comparison levels): for CO2 0.1%vol. according to Pettenkoffer's scale and 2.5%vol. for CH4 as the half of Lower Explosive Limit (LEL). The results show that the deeper baric drops anticipated could lead to a wider spread of both greenhouse gases in the vicinity of the shaft, especially along the prevailing wind direction. According to the results obtained, CO2 and CH4 with concentrations above their comparison levels are expected at a distance greater than 50m from the shaft when wind is present for CO2 and at a distance of 4.5m for CH4. Subsequent analysis of the results enabled the determination of functions for describing the concentration of gases along the wind direction line under the projected pressure drop. The results relate to a particular case, although the model could easily be modified to any other example of gas emissions from underground sites.

  16. Viscosity Models for Polymer Free CO2 Foam Fracturing Fluid with the Effect of Surfactant Concentration, Salinity and Shear Rate

    Directory of Open Access Journals (Sweden)

    Shehzad Ahmed

    2017-11-01

    Full Text Available High quality polymer free CO2 foam possesses unique properties that make it an ideal fluid for fracturing unconventional shales. In this paper, the viscosity of polymer free fracturing foam and its empirical correlations at high pressure high temperature (HPHT as a function of surfactant concentration, salinity, and shear rate are presented. Foams were generated using a widely-used surfactant, i.e., alpha olefin sulfonate (AOS in the presence of brine and a stabilizer at HPHT. Pressurize foam rheometer was used to find out the viscosity of CO2 foams at different surfactant concentration (0.25–1 wt % and salinity (0.5–8 wt % over a wide range of shear rate (10–500 s−1 at 1500 psi and 80 °C. Experimental results concluded that foam apparent viscosity increases noticeably until the surfactant concentration of 0.5 wt %, whereas, the increment in salinity provided a continuous increase in foam apparent viscosity. Nonlinear regression was performed on experimental data and empirical correlations were developed. Power law model for foam viscosity was modified to accommodate for the effect of shear rate, surfactant concentration, and salinity. Power law indices (K and n were found to be a strong function of surfactant concentration and salinity. The new correlations accurately predict the foam apparent viscosity under various stimulation scenarios and these can be used for fracture simulation modeling.

  17. Allocation of reserve-derived and currently assimilated carbon and nitrogen in seedlings of Helianthus annuus under sub-ambient and elevated CO growth conditions.

    Science.gov (United States)

    Lehmeier, Christoph A; Schäufele, Rudi; Schnyder, Hans

    2005-12-01

    Here, we analysed the transition from heterotrophic to autotrophic growth of the epigeal species sunflower (Helianthus annuus), and how transition is affected by CO(2). Growth analysis and steady-state (13)CO(2)/(12)CO(2) and (15)NO(3) (-)/(14)NO(3) (-) labelling were used to quantify reserve- and current assimilation-derived carbon (C) and nitrogen (N) allocation to shoots and roots in the presence of 200 and 1,000 micromol CO(2) mol(-1) air. Growth was not influenced by CO(2) until cotyledons unfolded. Then, C accumulation at elevated CO(2) increased to a rate 2-2.5 times higher than in sub-ambient CO(2) due to increased unit leaf rate (+120%) and leaf expansion (+60%). CO(2) had no effect on mobilization and allocation of reserve-derived C and N, even during the transition period. Export of autotrophic C from cotyledons began immediately following the onset of photosynthetic activity, serving roots and shoots near-simultaneously. Allocation of autotrophic C to shoots was increased at sub-ambient CO(2). The synchrony in transition from heterotrophic to autotrophic supply for different sinks in sunflower contrasts with the sequential transition reported for species with hypogeal germination.

  18. Emission of CO2 by the transport sector and the impact on the atmospheric concentration in Sao Paulo, Brazil.

    Science.gov (United States)

    Andrade, M. D. F.; Kitazato, C.; Perez-Martinez, P.; Nogueira, T.

    2014-12-01

    The Metropolitan Area of São Paulo (MASP) is impacted by the emission of 7 million vehicles, being 85% light-duty vehicles (LDV), 3% heavy-duty diesel vehicles (HDV)s, and 12% motorcycles. About 55% of LDVs burn a mixture of 78% gasoline and 22% ethanol (gasohol), 4% use hydrous ethanol (95% ethanol and 5% water), 38% are flex-fuel vehicles that are capable of burning both gasohol and hydrous ethanol and 3% use diesel (diesel + 5% bio-diesel). The owners of the flex-fuel vehicles decide to use ethanol or gasohol depending on the market price of the fuel. Many environmental programs were implemented to reduce the emissions by the LDV and HDV traffic; the contribution from the industrial sector has been decreasing as the industries have moved away from MASP, due to the high taxes applied to the productive sector. Due to the large contribution of the transport sector to CO2, its contribution is important in a regional scale. The total emission is estimated in 15327 million tons per year of CO2eq (60% by LDV, 38% HDV and 2% motorcycles). Measurements of CO2 performed with a Picarro monitor based on WS-CRDS (wavelength-scanned cavity ringdown spectroscopy) for the years 2012-2013 were performed. The sampling site was on the University of Sao Paulo campus (22o34´S, 46o44´W), situated in the west area of the city, surrounded by important traffic roads. The average data showed two peaks, one in the morning and the other in the afternoon, both associated with the traffic. Correlation analysis was performed between the concentrations and the number of vehicles, as a proxy for the temporal variation of the CO2 emission. The highest concentration was 430 ppm at 8:00am, associated to the morning peak hour of vehicles and the stable condition of the atmosphere. The average concentration was 406 ±12 ppm, considering all measured data. According to official inventories from the Environmental Agency (CETESB), the emission of CO2 has increased 39% from 1990 to 2008, associated

  19. Interactive effects of growth-limiting N supply and elevated atmospheric CO2 concentration on growth and carbon balance of Plantago major

    NARCIS (Netherlands)

    den Hertog, J; Stulen, G; Posthumus, F.S; Poorter, H

    To assess the interactions between concentration of atmospheric CO2 and N supply, the response of Plantago major ssp. pleiosperma Pilger to a doubling of the ambient CO2 concentration of 350 mu l l(-1) was investigated in a range of exponential rates of N addition. The relative growth rate (RGR) as

  20. 1.6 μm DIAL Measurement and Back Trajectory Analysis of CO2 Concentration Profiles in the Lower-Atmosphere

    Science.gov (United States)

    Shibata, Y.; Nagasawa, C.; Abo, M.

    2016-12-01

    Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities. In addition to the ground level CO2 network, vertical CO2 concentration profiles also play an important role for the estimation of the carbon budget and global warming in the inversion method. Especially, for the detailed analysis of forest carbon dynamics and CO2 fluxes of urban area, vertical CO2 concentration profiles with high spatial and temporal resolution in the lower atmosphere have been conducted by a differential absorption lidar (DIAL). We have observed several vertical profiles of CO2 concentrations for nighttime and daytime from 0.25 to 2.5 km altitude with range resolution of 300 m and integration time of 1 hour. In order to extract information on the origin of the CO2 masses, one day back trajectories were calculated by using a three dimensional (3-D) atmospheric transport model. In many cases, CO2 low concentration layers of over 1.5km altitude were flown by westerly winds from the forest. In another case, high concentration layers of CO2 were flown from the urban areas. As the spectra of absorption lines of any molecules are influenced basically by the temperature in the atmosphere, laser beams of three wavelengths around a CO2 absorption spectrum are transmitted alternately to the atmosphere for simultaneous measurements of CO2 concentration and temperature profiles. Moreover, a few processing algorithms of CO2-DIAL are also performed for improvement of measurement accuracy. For computation of trajectories and drawing their figures, the JRA-25 data provided by the cooperative research project for the JRA-25 long-term reanalysis of the Japan Meteorological Agency (JMA) and the Central Research Institute of Electric Power Industry (CRIEPI) and the NIPR trajectory model (Tomikawa and Sato, 2005; http://firp-nitram.nipr.ac.jp) were used. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and

  1. Technical Note: Long-term memory effect in the atmospheric CO2 concentration at Mauna Loa

    Directory of Open Access Journals (Sweden)

    C. Varotsos

    2007-01-01

    Full Text Available The monthly mean values of the atmospheric carbon dioxide concentration derived from in-situ air samples collected at Mauna Loa Observatory, Hawaii, USA during 1958–2004 (the longest continuous record available in the world are analyzed by employing the detrended fluctuation analysis to detect scaling behavior in this time series. The main result is that the fluctuations of carbon dioxide concentrations exhibit long-range power-law correlations (long memory with lag times ranging from four months to eleven years, which correspond to 1/f noise. This result indicates that random perturbations in the carbon dioxide concentrations give rise to noise, characterized by a frequency spectrum following a power-law with exponent that approaches to one; the latter shows that the correlation times grow strongly. This feature is pointing out that a correctly rescaled subset of the original time series of the carbon dioxide concentrations resembles the original time series. Finally, the power-law relationship derived from the real measurements of the carbon dioxide concentrations could also serve as a tool to improve the confidence of the atmospheric chemistry-transport and global climate models.

  2. The sensitivity of stand-scale photosynthesis and transpiration to changes in atmospheric CO2 concentration and climate

    Directory of Open Access Journals (Sweden)

    B. Kruijt

    1999-01-01

    Full Text Available The 3-dimensional forest model MAESTRO was used to simulate daily and annual photosynthesis and transpiration fluxes of forest stands and the sensitivity of these fluxes to potential changes in atmospheric CO2 concentration ([CO2], temperature, water stress and phenology. The effects of possible feed-backs from increased leaf area and limitations to leaf nutrition were simulated by imposing changes in leaf area and nitrogen content. Two different tree species were considered: Picea sitchensis (Bong. Carr., a conifer with long needle longevity and large leaf area, and Betula pendula Roth., a broad-leaved deciduous species with an open canopy and small leaf area. Canopy photosynthetic production in trees was predicted to increase with atmospheric [CO2] and length of the growing season and to decrease with increased water stress. Associated increases in leaf area increased production further only in the B. pendula canopy, where the original leaf area was relatively small. Assumed limitations in N uptake affected B. pendula more than P. sitchensis. The effect of increased temperature was shown to depend on leaf area and nitrogen content. The different sensitivities of the two species were related to their very different canopy structure. Increased [CO2] reduced transpiration, but larger leaf area, early leaf growth, and higher temperature all led to increased water use. These effects were limited by feedbacks from soil water stress. The simulations suggest that, with the projected climate change, there is some increase in stand annual `water use efficiency', but the actual water losses to the atmosphere may not always decrease.

  3. The method to calculate concentration of CO2 and H2S in the liquid phase.

    Directory of Open Access Journals (Sweden)

    YUDIN Pavel Evgenievich

    2017-08-01

    Full Text Available The article proposes the method to calculate the necessary concentration of dissolved gases in the liquid phase. It also deals with development of the computer program that could consider all the main parameters of the tests. The numerous mathematical calculations resulted in formulation of the method to calculate concentration of dissolved gases in the liquid phase. The implementation of the developed model in the form of the software product «Autoclave 2.1» is presented. The developed methodology for calculating the concentration of dissolved gases in the liquid phase is designed to perform accelerated tests that concern resistance of internal anticorrosive coatings of pipelines to aggressive media and explosive decompression, to intensify corrosion processes and to identify the main mechanisms and patterns of changes in the physical, mechanical and operational properties of coatings from hydrothermal influences of fishing environments.

  4. Effect of Fe ion concentration on corrosion of carbon steel in CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion behaviour of steel wires in solutions containing different concentrations of Fe2+ was investigated by the linear polarisation resistance method, while the evolution of pH was monitored in situ and changes of the Fe2+ concentration were monitored ex situ. Characterisation...... of the corrosion scales was performed using microscopic and diffraction techniques. Scale analysis revealed that the passivation of samples, exposed to initially highly Fe2+ supersaturated solution, occurred when a formation of a double layer took place, resulting in 30 times lower corrosion rate compared...... to samples tested in solutions without initial Fe2+....

  5. Effect of Fe ion concentration on corrosion of carbon steel in CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    In this work, the corrosion behaviour of steel wires in solutions containing different concentrations of Fe2+ was investigated by the linear polarisation resistance method, while the evolution of pH was monitored in situ and changes of the Fe2+ concentration were monitored ex situ. Characterisation...... of the corrosion scales was performed using microscopic and diffraction techniques. Scale analysis revealed that the passivation of samples, exposed to initially highly Fe2+ supersaturated solution, occurred when a formation of a double layer took place, resulting in 30 times lower corrosion rate compared...

  6. Effects of CO2 concentration on photosynthesis, transpiration and production of greenhouse fruit vegetable crops

    NARCIS (Netherlands)

    Nederhoff, E.M.

    1994-01-01

    The effect of the C0 2 concentration of the greenhouse air (C) in the range 200 to 1100 μmol mol -1was investigated in tomato ( Lycopersicon esculentum Mill.), cucumber ( Cucumis sativus L.), sweet

  7. the influence of co2+ concentration on the electrodeposition of znni ...

    African Journals Online (AJOL)

    M. Diafi K. Degheche, H. Ben Temam

    2017-01-01

    Jan 1, 2017 ... ABSTRACT. In this work we have done an experimental study of Zinc- Nickel composite coatings. For this, the influence of the cobalt concentration was the principal object in order to improve the resistance of the corrosion of the coatings, which has been made by electroplating on steel substrates ...

  8. A mainstream monitoring system for respiratory CO2 concentration and gasflow.

    Science.gov (United States)

    Yang, Jiachen; Chen, Bobo; Burk, Kyle; Wang, Haitao; Zhou, Jianxiong

    2016-08-01

    Continuous respiratory gas monitoring is an important tool for clinical monitoring. In particular, measurement of respiratory [Formula: see text] concentration and gasflow can reflect the status of a patient by providing parameters such as volume of carbon dioxide, end-tidal [Formula: see text] respiratory rate and alveolar deadspace. However, in the majority of previous work, [Formula: see text] concentration and gasflow have been studied separately. This study focuses on a mainstream system which simultaneously measures respiratory [Formula: see text] concentration and gasflow at the same location, allowing for volumetric capnography to be implemented. A non-dispersive infrared monitor is used to measure [Formula: see text] concentration and a differential pressure sensor is used to measure gasflow. In developing this new device, we designed a custom airway adapter which can be placed in line with the breathing circuit and accurately monitor relevant respiratory parameters. Because the airway adapter is used both for capnography and gasflow, our system reduces mechanical deadspace. The finite element method was used to design the airway adapter which can provide a strong differential pressure while reducing airway resistance. Statistical analysis using the coefficient of variation was performed to find the optimal driving voltage of the pressure transducer. Calibration between variations and flows was used to avoid pressure signal drift. We carried out targeted experiments using the proposed device and confirmed that the device can produce stable signals.

  9. An approach for verifying biogenic greenhouse gas emissions inventories with atmospheric CO2 concentration data

    Science.gov (United States)

    Stephen M Ogle; Kenneth Davis; Thomas Lauvaux; Andrew Schuh; Dan Cooley; Tristram O West; Linda S Heath; Natasha L Miles; Scott Richardson; F Jay Breidt; James E Smith; Jessica L McCarty; Kevin R Gurney; Pieter Tans; A Scott. Denning

    2015-01-01

    Verifying national greenhouse gas (GHG) emissions inventories is a critical step to ensure that reported emissions data to the United Nations Framework Convention on Climate Change (UNFCCC) are accurate and representative of a country's contribution to GHG concentrations in the atmosphere. Furthermore, verifying biogenic fluxes provides a check on estimated...

  10. Elevated CO2 concentration effects on reproductive phenology and seed yield among soybean cultivars

    Science.gov (United States)

    Seed yield increases in soybeans caused by increased growth at elevated carbon dioxide concentrations primarily result from increased numbers of pods. However, reasons for differences among cultivars in the increases in pod number caused by elevated carbon dioxide are not clear. In experiments in ...

  11. CO2 acclimation impacts leaf isoprene emissions: evidence from past to future CO2 levels

    Science.gov (United States)

    de Boer, Hugo; van der Laan, Annick; Dekker, Stefan; Holzinger, Rupert

    2017-04-01

    concentration and marginally decreases isoprene production owing to an increase in the electron demand for carbon fixation. In the long-term, acclimation to rising CO2 growth conditions leads to down regulation of both Jmax and Vcmax, which modulates the stimulating effect of rising CO2 on photosynthesis. This CO2 effect is most pronounced between sub-ambient to present CO2. Our results highlight that the LES-model provides a suitable theoretical framework to model changes in leaf isoprene emissions related to biochemical acclimation to rising CO2. References Harrison, S. P. et al: Volatile isoprenoid emissions from plastid to planet, New Phytol., 197(1), 49-57, 2013. Morfopoulos, C. et al: A model of plant isoprene emission based on available reducing power captures responses to atmospheric CO2, New Phytol., 203(1), 125-139, 2014.

  12. Development of a 2-micron Pulsed Differential Absorption Lidar for Atmospheric CO2 Concentration Measurement by Direct Detection Technique

    Science.gov (United States)

    Yu, J.; Singh, U. N.; Petros, M.; Bai, Y.

    2011-12-01

    Researchers at NASA Langley Research Center are developing a 2-micron Pulsed Differential Absorption Lidar instrument for ground and airborne measurements via direct detection method. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capbility by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement. A key component of the CO2 DIAL system, transceiver, is an existing, airborne ready, robust hardware which can provide 250mJ at 10Hz with double pulse format specifically designed for DIAL instrument. The exact wavelengths of the transceiver are controlled by well defined CW seed laser source to provide the required injection source for generating on-and-off line wavelength pulses sequentially. The compact, rugged, highly reliable transceiver is based on the unique Ho:Tm:YLF high-energy 2-micron pulsed laser technology. All the optical mounts are custom designed and have space heritage. They are designed to be adjustable and lockable and hardened to withstand vibrations that can occur in airborne operation. For the direct detection lidar application, a large primary mirror size is preferred. A 14 inch diameter telescope will be developed for this program. The CO2 DIAL/IPDA system requires many electronic functions to operate. These include diode, RF, seed laser, and PZT drivers; injection seeding detection and control; detector power supplies; and analog inputs to sample various sensors. Under NASA Laser Risk Reduction Program (LRRP), a control unit Compact Laser Electronics (CLE), is developed for the controlling the coherent wind lidar transceiver. Significant modifications and additions are needed to update it for CO2 lidar controls. The data acquisition system was built for ground CO2 measurement demonstration. The software will be updated for

  13. Effects of air current speed, light intensity and co2 concentration on photosynthesis and transpiration of plant leaves

    Science.gov (United States)

    Kitaya, Y.; Tsuruyama, J.; Shibuya, T.; Kiyota, M.

    To obtain basic data for adequate air circulation to promote gas exchange and growth of plants in closed plant culture modules in bioregenerative life support systems in space, the effects of air current speeds less than 0.8 m s-1 on transpiration (Tr) and net photosynthetic rates (Pn) of sweetpotato and barley leaves were determined using a leaf chamber method under different photosynthetic photon flux densities (PPFDs) and CO_2 concentrations. The air current speed inside the leaf chamber was controlled by controlling the input voltages for an air circulation fan. The leaf surface boundary layer resistance was determined by the evaporation rate of wet paper and the water vapor pressure difference between the paper and surrounding air in the leaf chamber. The Tr and Pn of leaves rapidly increased as the air current speed increased from 0.01 to 0.1 m s-1 and gradually increased from 0.1 to 0.8 m s-1. These changes are correspondent to the change of the leaf surface boundary layer resistance. The depression of Tr by low air current speeds was greater than that of Pn. Tr and Pn decreased by 0.5 and 0.7 times, respectively, as the air current speed decreased from 0.8 to 0.01 m s-1. The depressions of Tr and Pn by low air current speeds were most notable at PPFDs of 500 and 250 μmol m-2 s-1, respectively. The air current speeds affected Tr and Pn at a CO_2 concentration of 700 μmol mol-1 as well as at 400 μmol mol-1. The results confirmed the importance of controlling air movement for enhancing Tr and Pn under the relatively high PPFD and elevated CO_2 levels likely in plant culture systems in space.

  14. Associations between classroom CO2 concentrations and student attendance in Washington and Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Shendell, Derek G.; Prill, Richard; Fisk, William J.; Apte, Michael G.; Blake, David; Faulkner, David

    2004-01-01

    Student attendance in American public schools is a critical factor in securing limited operational funding. Student and teacher attendance influence academic performance. Limited data exist on indoor air and environmental quality (IEQ) in schools, and how IEQ affects attendance, health, or performance. This study explored the association of student absence with measures of indoor minus outdoor carbon dioxide concentration (dCO{sub 2}). Absence and dCO{sub 2} data were collected from 409 traditional and 25 portable classrooms from 14 schools located in six school districts in the states of Washington and Idaho. Study classrooms had individual heating, ventilation, and air conditioning (HVAC) systems, except two classrooms without mechanical ventilation. Classroom attributes, student attendance and school-level ethnicity, gender, and socioeconomic status (SES) were included in multivariate modeling. Forty-five percent of classrooms studied had short-term indoor CO{sub 2} concentrations above 1000 parts-per-million (ppm). A 1000 ppm increase in dCO{sub 2} was associated (p < 0.05) with a 0.5% to 0.9% decrease in annual average daily attendance (ADA), corresponding to a relative 10% to 20% increase in student absence. Outside air (ventilation) rates estimated from dCO{sub 2} and other collected data were not associated with absence. Annual ADA was 2% higher (p < 0.0001) in traditional than in portable classrooms.

  15. Advanced ETC/LSS computerized analytical models, CO2 concentration. Volume 1: Summary document

    Science.gov (United States)

    Taylor, B. N.; Loscutoff, A. V.

    1972-01-01

    Computer simulations have been prepared for the concepts of C02 concentration which have the potential for maintaining a C02 partial pressure of 3.0 mmHg, or less, in a spacecraft environment. The simulations were performed using the G-189A Generalized Environmental Control computer program. In preparing the simulations, new subroutines to model the principal functional components for each concept were prepared and integrated into the existing program. Sample problems were run to demonstrate the methods of simulation and performance characteristics of the individual concepts. Comparison runs for each concept can be made for parametric values of cabin pressure, crew size, cabin air dry and wet bulb temperatures, and mission duration.

  16. Simultaneous Measurements of CO2 Concentration and Temperature profiles using 1.6 μm DIAL in the Lower-Atmosphere

    Science.gov (United States)

    Shibata, Y.; Nagasawa, C.; Abo, M.

    2016-12-01

    High-accurate vertical carbon dioxide (CO2) profiles are highly desirable in the inverse method to improve quantification and understanding of the global sink and source of CO2, and also global climate change. We have developed a ground based 1.6μm differential absorption lidar (DIAL) to achieve measurements of vertical CO2 profiles in the atmosphere. As the spectra of absorption lines of any molecules are influenced basically by the temperature and pressure in the atmosphere, it is important to measure them simultaneously so that the better accuracy of the DIAL measurement is realized. The barometric formula can derive atmospheric pressure of each altitude using atmospheric pressure of ground level at the lidar site. Comparison of atmospheric pressure prlofiles calculated from this equation and those obtained from radiosonde observations at Tateno, Japan are consisted within 0.2 % below 3 km altitude. So, we have developed a 1.6 μm CO2 DIAL system for simultaneous measurements of the CO2 concentration and temperature profiles in the lower-atmosphere. Laser beams of three wavelengths around a CO2 absorption spectrum is transmitted alternately to the atmosphere. Moreover, the value of the retrieved CO2 concentration will be improved remarkably by processing the iteration assignment of CO2 concentration and temperature, which measured by these DIAL techniques. We have acheived vertical CO2 concentration and temperature profile from 0.5 to 2.0 km altitude by this DIAL system. In the next step, we will use this high accuracy CO2 concentration profile and back-trajectory analysis for the behavior analysis of the CO2 mass. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency.

  17. [Effects of elevated CO2 concentration and nitrogen deposition on the biomass accumulation and allocation in south subtropical main native tree species and their mixed communities].

    Science.gov (United States)

    Zhao, Liang; Zhou, Guo-yi; Zhang, De-qiang; Duan, Hong-lang; Liu, Ju-xiu

    2011-08-01

    A 5-year experiment was conducted to study the effects of simulated elevated CO2 concentration, nitrogen deposition, and their combination on the biomass accumulation and allocation in five south subtropical native tree species Schima superba, Ormosia pinnata, Acmena acuminatissima, Syzygium hancei, and Castanopsis hystrix and their mixed communities. The test tree species had different responses in their biomass accumulation and allocation to the elevated CO2 concentration and nitrogen deposition. Elevated CO2 concentration and nitrogen deposition increased the biomass of legume species by 49.3% and 71.0%, respectively, and promoted the biomass accumulation in sun species. Nitrogen deposition increased the biomass of shade-preference species significantly, but elevated CO2 concentration was in adverse. Elevated CO2 concentration inhibited the biomass allocation in the belowground part of sun species but promoted the biomass allocation in the belowground part of shade-preference species. Elevated CO2 concentration, nitrogen deposition, and their interaction all promoted the biomass accumulation in mixed communities. Elevated CO2 concentration increased the biomass accumulation in the belowground part of the communities, while nitrogen deposition increased the biomass accumulation in the aboveground part. Under the background of global climate change, Ormosia pinnata and Castanopsis hystrix tended to be the appropriate species for carbon fixation in south subtropical area.

  18. Transcriptional reprogramming and stimulation of leaf respiration by elevated CO2 concentration is diminished, but not eliminated, under limiting nitrogen supply.

    Science.gov (United States)

    Markelz, R J Cody; Lai, Lisa X; Vosseler, Lauren N; Leakey, Andrew D B

    2014-04-01

    Plant respiration responses to elevated CO2 concentration ( [CO2 ] ) have been studied for three decades without consensus about the mechanism of response. Positive effects of elevated [CO2 ] on leaf respiration have been attributed to greater substrate supply resulting from stimulated photosynthesis. Negative effects of elevated [CO2 ] on leaf respiration have been attributed to reduced demand for energy for protein turnover assumed to result from lower leaf N content. Arabidopsis thaliana was grown in ambient (370 ppm) and elevated (750 ppm) [CO2 ] with limiting and ample N availabilities. The stimulation of leaf dark respiration was attenuated in limiting N (+12%) compared with ample N supply (+30%). This response was associated with smaller stimulation of photosynthetic CO2 uptake, but not interactive effects of elevated CO2 and N supply on leaf protein, amino acids or specific leaf area. Elevated [CO2 ] also resulted in greater abundance of transcripts for many components of the respiratory pathway. A greater transcriptional response to elevated [CO2 ] was observed in ample N supply at midday versus midnight, consistent with reports that protein synthesis is greatest during the day. Greater foliar expression of respiratory genes under elevated [CO2 ] has now been observed in diverse herbaceous species, suggesting a widely conserved response. © 2013 John Wiley & Sons Ltd.

  19. Photosynthetic acclimation of overstory Populus tremuloides and understory Acer saccharum to elevated atmospheric CO2 concentration: interactions with shade and soil nitrogen

    Science.gov (United States)

    Mark E. Kubiske; Donald R. Zak; Kurt S. Pregitzer; Yu Takeuchi

    2002-01-01

    We exposed Populus tremuloides Michx. and Acer saccharum Marsh. to a factorial combination of ambient and elevated atmospheric CO2 concentrations ([CO2]) and high-nitrogen (N) and low-N soil treatments in open-top chambers for 3 years. Our objective was to compare photosynthetic...

  20. Short-term effects of fertilization on photosynthesis and leaf morphology of field-grown loblolly pine following long-term exposure to elevated CO2 concentration

    Science.gov (United States)

    Chris A. Maier; Sari Palmroth; Eric Ward

    2008-01-01

    We examined effects of a first nitrogen (N) fertilizer application on upper-canopy needle morphology and gas exchange in ~20-m-tall loblolly pine (Pinus taeda L.) exposed to elevated carbon dioxide concentration ([CO2]) for 9 years. Duke Forest free-air CO2 enrichment (FACE) plots were split and half of...

  1. Varying response of the concentration and content of soybean seed mineral elements, carbohydrates, organic acids, amino acids, protein, and oil to phosphorus starvation and CO2 enrichment

    Science.gov (United States)

    A detailed investigation of the concentration (g-1 seed weight) and content (g plant-1) of seed mineral elements and metabolic profile under phosphorus (P) starvation at ambient (aCO2) and elevated carbon dioxide (eCO2) in soybean is limited. Soybean plants were grown in a controlled environment at ...

  2. The role of sink strength and nitrogen availability in the down-regulation of photosynthetic capacity in field-grown Nicotiana tabacum at elevated CO2 concentration

    Science.gov (United States)

    Down-regulation of photosynthesis is one of the most frequent responses observed in C3 plants grown under elevated atmospheric CO2 concentration ([CO2]). Down-regulation is often attributed to an insufficient capacity of sink organs to use or store the increase in carbohydrate production in leaves t...

  3. Diagnostic system for measuring temperature, pressure, CO2 concentration and H2O concentration in a fluid stream

    Science.gov (United States)

    Partridge, Jr., William P.; Jatana, Gurneesh Singh; Yoo, Ji-Hyung; Parks, II, James E.

    2017-01-10

    A diagnostic system for measuring temperature, pressure, CO.sub.2 concentration and H.sub.2O concentration in a fluid stream is described. The system may include one or more probes that sample the fluid stream spatially, temporally and over ranges of pressure and temperature. Laser light sources are directed down pitch optical cables, through a lens and to a mirror, where the light sources are reflected back, through the lens to catch optical cables. The light travels through the catch optical cables to detectors, which provide electrical signals to a processer. The processer utilizes the signals to calculate CO.sub.2 concentration based on the temperatures derived from H.sub.2O vapor concentration. A probe for sampling CO.sub.2 and H.sub.2O vapor concentrations is also disclosed. Various mechanical features interact together to ensure the pitch and catch optical cables are properly aligned with the lens during assembly and use.

  4. Development of Compact 1.6 μm DIAL System for Measurement of Lower-Atmospheric CO2 Concentration Distribution

    Science.gov (United States)

    Nagasawa, C.; Shibata, Y.; Abo, M.

    2014-12-01

    For the detailed analysis of forest carbon dynamics and CO2 fluxes of urban area, the CO2 concentration measurement techniques with high spatial and temporal resolution are required in the lower atmosphere. We had developed the differential absorption lidar (DIAL) system to achieve high accurate measurements of vertical CO2 profiles and the vertical distribution of CO2 concentration from 2 km to 7 km altitude has been observed1. In order to measure the CO2 concentration distribution in the lower altitude, the dynamic range of the photon counter and the output power of transmitter of the CO2 DIAL have improved. We develope the compact 1.6 μm CO2 DIAL with the high-speed photon counter (10 GHz) and the small power transmitter to perform high-precision measurements of CO2 concentration profiles in the lower atmosphere. This compact mobile DIAL system has a 2 mJ OPG transmitter and a 25 cm coaxial telescope for measurements of limitted range. As the transmitter beam of this DIAL system is able to scan from -4 degree to 52 degree with elevation angle, the vertical distribution of lower CO2 concentration as well as the horizontal distribution from short range can be measured with high precision. The compact DIAL was conducted test observations and achieved successfully measurements of CO2 concentration profiles for the range from 0.25 to 3 km with integration time of 30 minutes and range resolution of 300 m. This work was financially supported by the System Development Program for Advanced Measurement and Analysis of the Japan Science and Technology Agency. REFERENCES Y. Shibata, C. Nagasawa, M. Abo, Proc. SPIE 8894, 889406 (2013); doi: 10.1117/12.2029359

  5. Soret Effect Study on High-Pressure CO2-Water Solutions Using UV-Raman Spectroscopy and a Concentric-Tube Optical Cell

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; McGrail, B. Peter; Maupin, Gary D.

    2012-01-01

    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O (or D2O), which were subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O at 10 MPa and temperatures near the critical point of CO2 had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude of |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19oC. The presence of 1 M NaCl did not make a difference. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for H2O were too weak to measure with confidence even at the limit of D2O solubility.

  6. Mesophyll conductance in leaves of Japanese white birch (Betula platyphylla var. japonica) seedlings grown under elevated CO2 concentration and low N availability.

    Science.gov (United States)

    Kitao, Mitsutoshi; Yazaki, Kenichi; Kitaoka, Satoshi; Fukatsu, Eitaro; Tobita, Hiroyuki; Komatsu, Masabumi; Maruyama, Yutaka; Koike, Takayoshi

    2015-12-01

    To test the hypothesis that mesophyll conductance (gm ) would be reduced by leaf starch accumulation in plants grown under elevated CO2 concentration [CO2 ], we investigated gm in seedlings of Japanese white birch grown under ambient and elevated [CO2 ] with an adequate and limited nitrogen supply using simultaneous gas exchange and chlorophyll fluorescence measurements. Both elevated [CO2 ] and limited nitrogen supply decreased area-based leaf N accompanied with a decrease in the maximum rate of Rubisco carboxylation (Vc,max ) on a CO2 concentration at chloroplast stroma (Cc ) basis. Conversely, only seedlings grown at elevated [CO2 ] under limited nitrogen supply had significantly higher leaf starch content with significantly lower gm among the treatment combinations. Based on a leaf anatomical analysis using microscopic photographs, however, there were no significant difference in the area of chloroplast surfaces facing intercellular space per unit leaf area among treatment combinations. Thicker cell walls were suggested in plants grown under limited N by increases in leaf mass per area subtracting non-structural carbohydrates. These results suggest that starch accumulation and/or thicker cell walls in the leaves grown at elevated [CO2 ] under limited N supply might hinder CO2 diffusion in chloroplasts and cell walls, which would be an additional cause of photosynthetic downregulation as well as a reduction in Rubisco activity related to the reduced leaf N under elevated [CO2 ]. © 2015 Scandinavian Plant Physiology Society.

  7. Preparation of Novel Li4 SiO4 Sorbents with Superior Performance at Low CO2 Concentration.

    Science.gov (United States)

    Yang, Xinwei; Liu, Wenqiang; Sun, Jian; Hu, Yingchao; Wang, Wenyu; Chen, Hongqiang; Zhang, Yang; Li, Xian; Xu, Minghou

    2016-07-07

    This work produced Li4 SiO4 sorbents through an impregnated-suspension method to overcome its typical poor performance at low CO2 concentrations. A SiO2 colloidal solution and two different organic lithium precursors were selected. A bulgy surface morphology (and thus, the significantly enlarged reacting surface area) was obtained for Li4 SiO4 , which contributed to the high absorption capacity. As a result, the capacity in cyclic tests at 15 vol % CO2 was approximately 8 times higher than conventional Li4 SiO4 prepared through a solid-state reaction. The phenomenon of a progressively increasing capacity (i.e., sustainable usage) was observed over the 40 cycles investigated, and this increasing trend continued to the last cycle. Correspondingly, over the course of the multicycle absorption/ desorption processes, the sorbents evolve from lacking porosity to having a high number of micron-sized pores. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Carbon Dioxide Production Responsibility on the Basis of comparing in Situ and mean CO2 Atmosphere Concentration Data

    OpenAIRE

    Mavrodiev, S. Cht.; Pekevski, L.; Vachev, B.

    2008-01-01

    The method is proposed for estimation of regional CO2 and other greenhouses and pollutants production responcibility. The comparison of CO2 local emissions reduction data with world CO2 atmosphere data will permit easy to judge for overall effect in curbing not only global warming but also chemical polution.

  9. Changes in Air CO2 Concentration Differentially Alter Transcript Levels of NtAQP1 and NtPIP2;1 Aquaporin Genes in Tobacco Leaves

    Directory of Open Access Journals (Sweden)

    Francesca Secchi

    2016-04-01

    Full Text Available The aquaporin specific control on water versus carbon pathways in leaves is pivotal in controlling gas exchange and leaf hydraulics. We investigated whether Nicotiana tabacum aquaporin 1 (NtAQP1 and Nicotiana tabacum plasma membrane intrinsic protein 2;1 (NtPIP2;1 gene expression varies in tobacco leaves subjected to treatments with different CO2 concentrations (ranging from 0 to 800 ppm, inducing changes in photosynthesis, stomatal regulation and water evaporation from the leaf. Changes in air CO2 concentration ([CO2] affected net photosynthesis (Pn and leaf substomatal [CO2] (Ci. Pn was slightly negative at 0 ppm air CO2; it was one-third that of ambient controls at 200 ppm, and not different from controls at 800 ppm. Leaves fed with 800 ppm [CO2] showed one-third reduced stomatal conductance (gs and transpiration (E, and their gs was in turn slightly lower than in 200 ppm– and in 0 ppm–treated leaves. The 800 ppm air [CO2] strongly impaired both NtAQP1 and NtPIP2;1 gene expression, whereas 0 ppm air [CO2], a concentration below any in vivo possible conditions and specifically chosen to maximize the gene expression alteration, increased only the NtAQP1 transcript level. We propose that NtAQP1 expression, an aquaporin devoted to CO2 transport, positively responds to CO2 scarcity in the air in the whole range 0–800 ppm. On the contrary, expression of NtPIP2;1, an aquaporin not devoted to CO2 transport, is related to water balance in the leaf, and changes in parallel with gs. These observations fit in a model where upregulation of leaf aquaporins is activated at low Ci, while downregulation occurs when high Ci saturates photosynthesis and causes stomatal closure.

  10. Changes in Air CO2 Concentration Differentially Alter Transcript Levels of NtAQP1 and NtPIP2;1 Aquaporin Genes in Tobacco Leaves

    Science.gov (United States)

    Secchi, Francesca; Schubert, Andrea; Lovisolo, Claudio

    2016-01-01

    The aquaporin specific control on water versus carbon pathways in leaves is pivotal in controlling gas exchange and leaf hydraulics. We investigated whether Nicotiana tabacum aquaporin 1 (NtAQP1) and Nicotiana tabacum plasma membrane intrinsic protein 2;1 (NtPIP2;1) gene expression varies in tobacco leaves subjected to treatments with different CO2 concentrations (ranging from 0 to 800 ppm), inducing changes in photosynthesis, stomatal regulation and water evaporation from the leaf. Changes in air CO2 concentration ([CO2]) affected net photosynthesis (Pn) and leaf substomatal [CO2] (Ci). Pn was slightly negative at 0 ppm air CO2; it was one-third that of ambient controls at 200 ppm, and not different from controls at 800 ppm. Leaves fed with 800 ppm [CO2] showed one-third reduced stomatal conductance (gs) and transpiration (E), and their gs was in turn slightly lower than in 200 ppm– and in 0 ppm–treated leaves. The 800 ppm air [CO2] strongly impaired both NtAQP1 and NtPIP2;1 gene expression, whereas 0 ppm air [CO2], a concentration below any in vivo possible conditions and specifically chosen to maximize the gene expression alteration, increased only the NtAQP1 transcript level. We propose that NtAQP1 expression, an aquaporin devoted to CO2 transport, positively responds to CO2 scarcity in the air in the whole range 0–800 ppm. On the contrary, expression of NtPIP2;1, an aquaporin not devoted to CO2 transport, is related to water balance in the leaf, and changes in parallel with gs. These observations fit in a model where upregulation of leaf aquaporins is activated at low Ci, while downregulation occurs when high Ci saturates photosynthesis and causes stomatal closure. PMID:27089333

  11. Rising CO2 from historical concentrations enhances the physiological performance of Brassica napus seedlings under optimal water supply but not under reduced water availability.

    Science.gov (United States)

    Faralli, Michele; Grove, Ivan G; Hare, Martin C; Kettlewell, Peter S; Fiorani, Fabio

    2017-02-01

    The productivity of many important crops is significantly threatened by water shortage, and the elevated atmospheric CO2 can significantly interact with physiological processes and crop responses to drought. We examined the effects of three different CO2 concentrations (historical ~300 ppm, ambient ~400 ppm and elevated ~700 ppm) on physiological traits of oilseed rape (Brassica napus L.) seedlings subjected to well-watered and reduced water availability. Our data show (1) that, as expected, increasing CO2 level positively modulates leaf photosynthetic traits, leaf water-use efficiency and growth under non-stressed conditions, although a pronounced acclimation of photosynthesis to elevated CO2 occurred; (2) that the predicted elevated CO2 concentration does not reduce total evapotranspiration under drought when compared with present (400 ppm) and historical (300 ppm) concentrations because of a larger leaf area that does not buffer transpiration; and (3) that accordingly, the physiological traits analysed decreased similarly under stress for all CO2 concentrations. Our data support the hypothesis that increasing CO2 concentrations may not significantly counteract the negative effect of increasing drought intensity on Brassica napus performance. © 2016 John Wiley & Sons Ltd.

  12. Evolutionary differences in Δ13C detected between spore and seed bearing plants following exposure to a range of atmospheric O2:CO2 ratios; implications for paleoatmosphere reconstruction

    Science.gov (United States)

    Porter, Amanda S.; Yiotis, Charilaos; Montañez, Isabel P.; McElwain, Jennifer C.

    2017-09-01

    The stable carbon isotopes of fossil plants are a reflection of the atmosphere and environment in which they grew. Fossil plant remains have thus stored information about the isotopic composition and concentration of atmospheric carbon dioxide (pCO2) and possibly pO2 through time. Studies to date, utilizing extant plants, have linked changes in plant stable carbon isotopes (δ13Cp) or carbon isotope discrimination (Δ13C) to changes in pCO2 and/or pO2. These studies have relied heavily on angiosperm representatives, a phylogenetic group only present in the fossil record post-Early Cretaceous (∼140 million years ago (mya)), whereas gymnosperms, monilophytes and lycophytes dominated terrestrial ecosystems prior to this time. The aim of this study was to expand our understanding of carbon isotope discrimination in all vascular plant groups of C3 plants including lycophytes, monilophytes, gymnosperms and angiosperms, under elevated CO2 and sub-ambient O2 to explore their utility as paleo-atmospheric proxies. To achieve this goal, plants were grown in controlled environment chambers under a range of O2:CO2 ratio treatments. Results reveal a strong phylogenetic dependency on Δ13C, where spore-bearing (lycophytes and monilophytes) have significantly higher 13C discrimination than seed plants (gymnosperms and angiosperms) by ∼5‰. We attribute this strong phylogenetic signal to differences in Ci/Ca likely mediated by fundamental differences in how spore and seed bearing plants control stomatal aperture. Decreasing O2:CO2 ratio in general resulted in increased carbon isotope discrimination in all plant groups. Notably, while all plant groups respond unidirectionally to elevated atmospheric CO2 (1900 ppm and ambient O2), they do not respond equally to sub-ambient O2 (16%). We conclude that (1) Δ13C has a strong phylogenetic or 'reproductive grade' bias, whereby Δ13C of spore reproducing plants is significantly different to seed reproducing taxa. (2) Δ13C increases

  13. CO2 uit buitenlucht

    NARCIS (Netherlands)

    Weel, van P.A.; Vanthoor, B.H.E.

    2016-01-01

    The supply of additional CO2 in a greenhouse will be restricted in the future. The concentration in outside air has risen above 400 ppm. This may open the possibility to blow this air through the canopy to increase growth. In this project, the vertical CO2 concentration was measured in a vertical

  14. Detection of NO sub x,C2H4 concentrations by using CO and CO2 lasers

    Science.gov (United States)

    Gengchen, W.; Qinxin, K.

    1986-01-01

    A laser, especially the infrared line tunable laser, opens up a new way to monitor the atmospheric environment, and already has gotten effective practical application. One of the most serious problems in open path remote measurement at atmospheric pressure is the broadening effect which leads to increased linewidths, spectral interferences, and, as a result, tends to reduce detection sensitivity, so measuring laser wavelengths should be selected carefully, and interaction between the measuring wavelength and gas to be measured must be known very well. Therefore, N2O, No, NO2, CH4, NH3 and C2H4 absorption properties at some lines of CO and CO2 line tunable lasers were studied. The absorption coefficients of NO, NO2, and C2H4; some results on detection of NO sub x, C2H4 concentrations in both laboratory and field; and selection of measuring wavelengths and error analysis are discussed.

  15. Quantifying the Multivariate ENSO Index (MEI) coupling to CO2 concentration and to the length of day variations

    CERN Document Server

    Mazzarella, A; Scafetta, N

    2012-01-01

    The El Ni\\~no Southern Oscillation (ENSO) is the Earth's strongest climate fluctuation on inter-annual time-scales and has global impacts although originating in the tropical Pacific. Many point indices have been developed to describe ENSO but the Multivariate ENSO Index (MEI) is considered the most representative since it links six different meteorological parameters measured over the tropical Pacific. Extreme values of MEI are correlated to the extreme values of atmospheric CO2 concentration rate variations and negatively correlated to equivalent scale extreme values of the length of day (LOD) rate variation. We evaluate a first order conversion function between MEI and the other two indexes using their annual rate of variation. The quantification of the strength of the coupling herein evaluated provides a quantitative measure to test the accuracy of theoretical model predictions. Our results further confirm the idea that the major local and global Earth-atmosphere system mechanisms are significantly couple...

  16. Finlay-Wilkinson's regression coefficient as a pre-screening criterion for yield responsiveness to elevated atmospheric CO2 concentration in crops.

    Science.gov (United States)

    Kumagai, Etsushi; Homma, Koki; Kuroda, Eiki; Shimono, Hiroyuki

    2016-11-01

    The rising atmospheric CO2 concentration ([CO2 ]) can increase crop productivity, but there are likely to be intraspecific variations in the response. To meet future world food demand, screening for genotypes with high [CO2 ] responsiveness will be a useful option, but there is no criterion for high [CO2 ] responsiveness. We hypothesized that the Finlay-Wilkinson regression coefficient (RC) (for the relationship between a genotype's yield versus the mean yield of all genotypes in a specific environment) could serve as a pre-screening criterion for identifying genotypes that respond strongly to elevated [CO2 ]. We collected datasets on the yield of 6 rice and 10 soybean genotypes along environmental gradients and compared their responsiveness to elevated [CO2 ] based on the regression coefficients (i.e. the increases of yield per 100 µmol mol(-1) [CO2 ]) identified in previous reports. We found significant positive correlations between the RCs and the responsiveness of yield to elevated [CO2 ] in both rice and soybean. This result raises the possibility that the coefficient of the Finlay-Wilkinson relationship could be used as a pre-screening criterion for [CO2 ] responsiveness. © 2016 Scandinavian Plant Physiology Society.

  17. Dynamics of the terrestrial biosphere, climate and atmospheric CO2 concentration during interglacials: a comparison between Eemian and Holocene

    Directory of Open Access Journals (Sweden)

    G. Schurgers

    2006-01-01

    Full Text Available A complex earth system model (atmosphere and ocean general circulation models, ocean biogeochemistry and terrestrial biosphere was used to perform transient simulations of two interglacial sections (Eemian, 128–113 ky B.P., and Holocene, 9 ky B.P.–present. The changes in terrestrial carbon storage during these interglacials were studied with respect to changes in the earth's orbit. The effects of different climate factors on changes in carbon storage were studied in offline experiments in which the vegetation model was forced only with temperature, hydrological parameters, radiation, or CO2 concentration from the transient runs. The largest anomalies in terrestrial carbon storage were caused by temperature changes. However, the increase in storage due to forest expansion and increased photosynthesis in the high latitudes was nearly balanced by the decrease due to increased respiration. Large positive effects on carbon storage were caused by an enhanced monsoon circulation in the subtropics between 128 and 121 ky B.P. and between 9 and 6 ky B.P., and by increases in incoming radiation during summer for 45° to 70° N compared to a control simulation with present-day insolation. Compared to this control simulation, the net effect of these changes was a positive carbon storage anomaly in the terrestrial biosphere of about 200 Pg C for 125 ky B.P. and 7 ky B.P., and a negative anomaly around 150 Pg C for 116 ky B.P. Although the net increases for Eemian and Holocene were rather similar, the magnitudes of the processes causing these effects were different. The decrease in terrestrial carbon storage during the experiments was the main driver of an increase in atmospheric CO2 concentration during both the Eemian and the Holocene.

  18. [Effects of elevated atmospheric CO2 concentration and nitrogen addition on the growth of Calamagrostis angustifolia in Sanjiang Plain freshwater marsh].

    Science.gov (United States)

    Zhao, Guang-Ying; Liu, Jing-Shuang; Wang, Yang

    2011-06-01

    By using open top chamber, an experiment with two levels of atmospheric CO2 concentration (350 and 700 micromol x mol(-1)) and three levels of nitrogen supply (0, 5, and 15 g N x m(-2)) was conducted to investigate the effects of elevated atmospheric CO2 and nitrogen supply on the growth of Calamagrostis angustifolia in the freshwater marsh of Sanjiang Plain. Under elevated atmospheric CO2 concentration, the phenophase of C. angustifolia advanced. Jointing stage was advanced by 1-2 d, and maturity stage was advanced by 3 d. Elevated atmospheric CO2 promoted the tillering of C. angustifolia, with the increment of tiller number under 0, 5, and 15 g x m(-2) of nitrogen supply being 8.2% (P 0.05), respectively. Elevated atmospheric CO2 also promoted the aboveground biomass at jointing and heading stages, the increment being 12.4% and 20.9% (P CO2 concentration depended on nitrogen supply level. Under sufficient nitrogen supply, the promotion effect of elevated atmospheric CO2 concentration on the biomass of C. angustifolia was higher.

  19. Water reuse: >90% water yield in MBR/RO through concentrate recycling and CO2 addition as scaling control.

    Science.gov (United States)

    Joss, Adriano; Baenninger, Claudia; Foa, Paolo; Koepke, Stephan; Krauss, Martin; McArdell, Christa S; Rottermann, Karin; Wei, Yuansong; Zapata, Ana; Siegrist, Hansruedi

    2011-11-15

    Over 1.5 years continuous piloting of a municipal wastewater plant upgraded with a double membrane system (ca. 0.6 m(3) d(-1) of product water produced) have demonstrated the feasibility of achieving high water quality with a water yield of 90% by combining a membrane bioreactor (MBR) with a submerged ultrafiltration membrane followed by a reverse osmosis membrane (RO). The novelty of the proposed treatment scheme consists of the appropriate conditioning of MBR effluent prior to the RO and in recycling the RO concentrates back to the biological unit. All the 15 pharmaceuticals measured in the influent municipal sewage were retained below 100 ng L(-1), a proposed quality parameter, and mostly below detection limits of 10 ng L(-1). The mass balance of the micropollutants shows that these are either degraded or discharged with the excess concentrate, while only minor quantities were found in the excess sludge. The micropollutant load in the concentrate can be significantly reduced by ozonation. A low treated water salinity (recycled to the biological unit where CO(2) is stripped by aeration. This causes precipitation to occur in the bioreactor bulk, where it is much less of a process issue. SiO(2) is the sole exception. Equilibrium modeling of precipitation reactions confirms the effectiveness of this scaling-mitigation approach for CaCO(3) precipitation, calcium phosphate and sulfate minerals. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Integrated testing of an electrochemical depolarized CO2 concentrator /EDC/ and a Bosch CO2 reduction subsystem /BRS/. [in spaceborne oxygen reclamation system

    Science.gov (United States)

    Schubert, F. H.; Clark, D. C.; Quattrone, P. D.

    1976-01-01

    An oxygen reclamation system (ORS) in a spacecraft has the task to revitalize the spacecraft atmosphere by recovering the elementary oxygen from metabolically produced carbon dioxide and water vapor. Life support subsystems which can form such an ORS are an electrochemical depolarized carbon dioxide concentrator (EDC), a Bosch carbon dioxide reduction subsystem (BRS), and an oxygen generation subsystem (OGS). A total recovery of the oxygen from metabolically generated carbon dioxide can be obtained with the aid of system composed of the considered three subsystems. Attention is given to the control concept which assures an integrated operation of the EDC, BRS, and OGS. A description is presented of the test results obtained during 86 days of testing.

  1. A general circulation model study of the effects of faster rotation rate, enhanced CO2 concentration, and reduced solar forcing: Implications for the faint young sun paradox

    Science.gov (United States)

    Jenkins, Gregory S.

    1993-01-01

    Solar energy at the top of the atmosphere (solar constant), rotation rate, and carbon dioxide (CO2) may have varied significantly over Earth's history, especially during the earliest times. The sensitivity of a general circulation model to faster rotation, enhanced CO2 concentration, and reduced solar constant is presented. The control simulation of this study has a solar constant reduced by 10% the present amount, zero land fraction using a swamp ocean surface, CO2 concentrations of 330 ppmv, present-day rotation rate, and is integrated under mean diurnal and seasonal solar forcing. Four sensitivity test are performed under zero land fraction and reduced solar constant conditions by varying the earth's rotation rate atmospheric CO2 concentration and solar constant. The global mean sea surface temperatures (SSTs) compared to the control simulation: were 6.6 K to 12 K higher than the control's global mean temperature of 264.7 K. Sea ice is confined to higher latitudes in each experiment compared to the control, with ice-free areas equatorward of the subtropics. The warm SSTs are associated with a 20% reduction in clouds for the rotation rate experiments and higher CO2 concentrations in the other experiments. These results are in contrast to previous studies that have used energy balance and radiative convective models. Previous studies required a much larger atmospheric CO2 increase to prevent an ice-covered Earth. The results of the study, suggest that because of its possible feedback with clouds, the general circulation of the atmosphere should be taken into account in understanding the climate of early Earth. While higher CO2 concentrations are likely in view of the results, very large atmospheric CO2 concentrations may not be necessary to counterbalance the lower solar constant that existed early in Earth's history.

  2. Effects of elevated CO2 concentration and nitrogen supply on biomass and active carbon of freshwater marsh after two growing seasons in Sanjiang Plain, Northeast China.

    Science.gov (United States)

    Zhao, Guangying; Liu, Jingshuang; Wang, Yang; Dou, Jingxin; Dong, Xiaoyong

    2009-01-01

    An experiments were carried out with treatments differing in nitrogen supply (0, 5 and 15 g N/m2) and CO2 levels (350 and 700 micromol/mol) using OTC (open top chamber) equipment to investigate the biomass of Calamagrostis angustifolia and soil active carbon contents after two years. The results showed that elevated CO2 concentration increased the biomass of C. angustifolia and the magnitude of response varied with each growth period. Elevated CO2 concentration has increased aboveground biomass by 16.7% and 17.6% during the jointing and heading periods and only 3.5% and 9.4% during dough and maturity periods. The increases in belowground biomass due to CO2 elevation was 26.5%, 34.0% and 28.7% during the heading, dough and maturity periods, respectively. The responses of biomass to enhanced CO2 concentrations are differed in N levels. Both the increase of aboveground biomass and belowground biomass were greater under high level of N supply (15 g N/m2). Elevated CO2 concentration also increased the allocation of biomass and carbon in root. Under elevated CO2 concentration, the average values of active carbon tended to increase. The increases of soil active soil contents followed the sequence of microbial biomass carbon (10.6%) > dissolved organic carbon (7.5%) > labile oxidable carbon (6.6%) > carbohydrate carbon (4.1%). Stepwise regressions indicated there were significant correlations between the soil active carbon contents and plant biomass. Particularly, microbial biomass carbon, labile oxidable carbon and carbohydrate carbon were found to be correlated with belowground biomass, while dissolved organic carbon has correlation with aboveground biomass. Therefore, increased biomass was regarded as the main driving force for the increase in soil active organic carbon under elevated CO2 concentration.

  3. Response of the rhizosphere prokaryotic community of barley (Hordeum vulgare L.) to elevated atmospheric CO2 concentration in open-top chambers.

    Science.gov (United States)

    Szoboszlay, Márton; Näther, Astrid; Mitterbauer, Esther; Bender, Jürgen; Weigel, Hans-Joachim; Tebbe, Christoph C

    2017-08-01

    The effect of elevated atmospheric CO2 concentration [CO2 ] on the diversity and composition of the prokaryotic community inhabiting the rhizosphere of winter barley (Hordeum vulgare L.) was investigated in a field experiment, using open-top chambers. Rhizosphere samples were collected at anthesis (flowering stage) from six chambers with ambient [CO2 ] (approximately 400 ppm) and six chambers with elevated [CO2 ] (700 ppm). The V4 region of the 16S rRNA gene was PCR-amplified from the extracted DNA and sequenced on an Illumina MiSeq instrument. Above-ground plant biomass was not affected by elevated [CO2 ] at anthesis, but plants exposed to elevated [CO2 ] had significantly higher grain yield. The composition of the rhizosphere prokaryotic communities was very similar under ambient and elevated [CO2 ]. The dominant taxa were Bacteroidetes, Actinobacteria, Alpha-, Gamma-, and Betaproteobacteria. Elevated [CO2 ] resulted in lower prokaryotic diversity in the rhizosphere, but did not cause a significant difference in community structure. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  4. Short-term effect of elevated CO2 concentration (0.5%) on mitochondria in diploid and tetraploid black locust (Robinia pseudoacacia L.).

    Science.gov (United States)

    Xu, Fuling; Jiang, Mingquan; Meng, Fanjuan

    2017-07-01

    Recent increases in atmospheric CO 2 concentration have affected the growth and physiology of plants. In this study, plants were grown with 0.5% CO 2 for 0, 3, and 6 days. The anatomy, fluorescence intensity of H2O2, respiration rate, and antioxidant activities of the mitochondria were analyzed in diploid (2×) and tetraploid (4×) black locust (Robinia pseudoacacia L.). Exposure to 0.5% CO 2 resulted in clear structural alterations and stomatal closure in the mitochondria. Reduced membrane integrity and increased structural damage were observed in 2× plants at 6 days. However, after 0.5% CO 2 treatment, little structural damage was observed in 4× plants. Under severe stress, H2O2 and malondialdehyde were dramatically induced in both 2× and 4× plants. Proline remains unchanged at an elevated CO 2 concentration in 4× plants. Moreover, the total respiration and alternative respiration rates decreased in both 2× and 4× plants. In contrast, the cytochrome pathway showed no decrease in 2× plants and even increased slightly in 4× plants. The antioxidant enzymes and nonenzymatic antioxidants, which are related to the ascorbate-glutathione pathway, were inhibited following CO 2 exposure. These analyses indicated that 4× and 2× plants were damaged by 0.5% CO 2 but the former were more resistant than the latter, and this may be due to increases in antioxidant enzymes and nonenzymatic antioxidants and stabilized membrane structure.

  5. Weak hydrothermal carbonation of the Ongeluk volcanics: evidence for low CO2 concentrations in seawater and atmosphere during the Paleoproterozoic global glaciation

    Science.gov (United States)

    Shibuya, Takazo; Komiya, Tsuyoshi; Takai, Ken; Maruyama, Shigenori; Russell, Michael J.

    2017-12-01

    It was previously revealed that the total CO2 concentration in seawater decreased during the Late Archean. In this paper, to assess the secular change of total CO2 concentration in seawater, we focused on the Paleoproterozoic era when the Earth experienced its first recorded global glaciation. The 2.4 Ga Ongeluk Formation outcrops in the Kaapvaal Craton, South Africa. The formation consists mainly of submarine volcanic rocks that have erupted during the global glaciation. The undeformed lavas are mostly carbonate-free but contain rare disseminated calcites. The carbon isotope ratio of the disseminated calcite (δ13Ccc vs. VPDB) ranges from - 31.9 to - 13.2 ‰. The relatively low δ13Ccc values clearly indicate that the carbonation was partially contributed by 13C-depleted CO2 derived from decomposition of organic matter beneath the seafloor. The absence of δ13Ccc higher than - 13.2‰ is consistent with the exceptionally 13C-depleted CO2 in the Ongeluk seawater during glaciation. The results suggest that carbonation occurred during subseafloor hydrothermal circulation just after the eruption of the lavas. Previously, it was reported that the carbonate content in the uppermost subseafloor crust decreased from 3.2 to 2.6 Ga, indicating a decrease in total CO2 concentration in seawater during that time. However, the average CO2 (as carbonate) content in the Ongeluk lavas (< 0.001 wt%) is much lower than those of 2.6 Ga representatives and even of modern equivalents. This finding suggests that the total CO2 concentration in seawater further decreased during the period between 2.6 and 2.4 Ga. Thus, the very low content of carbonate in the Ongeluk lavas is probable evidence for the extremely low CO2 concentration in seawater during the global glaciation. Considering that the carbonate content of the subseafloor crusts also shows a good correlation with independently estimated atmospheric pCO2 levels through the Earth history, it seem highly likely that the low

  6. A Case Study on Observed and Simulated CO2 Concentration Profiles in Hefei based on Raman Lidar and GEOS-Chem Model

    Directory of Open Access Journals (Sweden)

    Wang Yinan

    2016-01-01

    Full Text Available Observations of atmospheric CO2 concentration profiles provide significative constraints on the global/regional inversions of carbon sources and sinks. Anhui Institute of Optics and Fine Mechanics of Chinese Academy of Sciences developed a Raman Lidar system to detect the vertical distribution of atmospheric CO2. This paper compared the observations with the modeled results from a three-dimensional global chemistry transport model-GEOS-Chem, which showed a good agreement in the trend of change with lidar measurements. The case study indicated a potential for better simulating vertical distribution of atmospheric CO2 by combining with lidar measurements.

  7. Effects of Co2 Concentrations and light intensity on photosynthesis of a rootless submerged plant, ceratophyllum demersum L., used for aquatic food production in bioregenerative life support systems

    Science.gov (United States)

    Kitaya, Y.; Okayama, T.; Murakami, K.; Takeuchi, T.

    Aquatic higher plants are likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO2 to O2 and remedying water quality in addition to green microalgae. In the present study, the effects of culture conditions on the net photosynthetic rate of a rootless submerged plant, Ceratophyllum demersum L., was investigated to determine the optimum culture conditions for plant function in aquatic food production modules including both plant culture and fish culture systems . The net photosynthetic rate in plants was determined by the increase in dissolved O2 concentrations in a closed vessel containing a plantlet and water. The water in the vessel was aerated sufficiently with a gas containing a known level CO 2 gas mixed with N2 gas before closing the vessel. The CO 2 concentrations in the aerating gas ranged from 0.3 to 100 mmol mol-1 . Photosynthetic photon flux density (PPFD) in the vessel ranged from 0 (dark) to 1.0 mmol m-2 s-1 , which was controlled with a metal halide lamp. Temperature was kept at 28 C. The net photosynthetic rate increased with increasing PPFD levels and was saturated at 0.2 and 0.5 mmol m-2 s-1 PPFD under CO 2 levels of 1.0 and 3.0 mmol mol-1 , respectively. The net photosynthetic rate increased with increasing CO2 levels from 0.3 to 3.0 mmol mol-1 showing the maximum value, 70 nmolO 2 gDW s at 3.0 mmol mol-1 CO2 and gradually decreased with increasing CO 2 levels from 3.0 to 100 mmol mol-1 . The results demonstrate that Ceratophyllum demersum L. could be an efficient CO 2 to O2 converter under a 3.0 mmol mol-1 CO2 level and relatively low PPFD levels in aquatic food production modules.

  8. Photosynthetic Performance of the Red Alga Pyropia haitanensis During Emersion, With Special Reference to Effects of Solar UV Radiation, Dehydration and Elevated CO2 Concentration.

    Science.gov (United States)

    Xu, Juntian; Gao, Kunshan

    2015-11-01

    Macroalgae distributed in intertidal zones experience a series of environmental changes, such as periodical desiccation associated with tidal cycles, increasing CO2 concentration and solar UVB (280-315 nm) irradiance in the context of climate change. We investigated how the economic red macroalga, Pyropia haitanensis, perform its photosynthesis under elevated atmospheric CO2 concentration and in the presence of solar UV radiation (280-400 nm) during emersion. Our results showed that the elevated CO2 (800 ppmv) significantly increased the photosynthetic carbon fixation rate of P. haitanensis by about 100% when the alga was dehydrated. Solar UV radiation had insignificant effects on the net photosynthesis without desiccation stress and under low levels of sunlight, but significantly inhibited it with increased levels of desiccation and sunlight intensity, to the highest extent at the highest levels of water loss and solar radiation. Presence of UV radiation and the elevated CO2 acted synergistically to cause higher inhibition of the photosynthetic carbon fixation, which exacerbated at higher levels of desiccation and sunlight. While P. haitanensis can benefit from increasing atmospheric CO2 concentration during emersion under low and moderate levels of solar radiation, combined effects of elevated CO2 and UV radiation acted synergistically to reduce its photosynthesis under high solar radiation levels during noon periods. © 2015 The American Society of Photobiology.

  9. Advances in understanding the cyanobacterial CO2-concentrating-mechanism (CCM): functional components, Ci transporters, diversity, genetic regulation and prospects for engineering into plants.

    Science.gov (United States)

    Price, G Dean; Badger, Murray R; Woodger, Fiona J; Long, Ben M

    2008-01-01

    Cyanobacteria have evolved a significant environmental adaptation, known as a CO(2)-concentrating-mechanism (CCM), that vastly improves photosynthetic performance and survival under limiting CO(2) concentrations. The CCM functions to transport and accumulate inorganic carbon actively (Ci; HCO(3)(-), and CO(2)) within the cell where the Ci pool is utilized to provide elevated CO(2) concentrations around the primary CO(2)-fixing enzyme, ribulose bisphosphate carboxylase-oxygenase (Rubisco). In cyanobacteria, Rubisco is encapsulated in unique micro-compartments known as carboxysomes. Cyanobacteria can possess up to five distinct transport systems for Ci uptake. Through database analysis of some 33 complete genomic DNA sequences for cyanobacteria it is evident that considerable diversity exists in the composition of transporters employed, although in many species this diversity is yet to be confirmed by comparative phenomics. In addition, two types of carboxysomes are known within the cyanobacteria that have apparently arisen by parallel evolution, and considerable progress has been made towards understanding the proteins responsible for carboxysome assembly and function. Progress has also been made towards identifying the primary signal for the induction of the subset of CCM genes known as CO(2)-responsive genes, and transcriptional regulators CcmR and CmpR have been shown to regulate these genes. Finally, some prospects for introducing cyanobacterial CCM components into higher plants are considered, with the objective of engineering plants that make more efficient use of water and nitrogen.

  10. Effects of Altered Weather Variables and Increased CO2 Concentrations on the Main Agricultural Crops of California's Central Valley Project

    Science.gov (United States)

    Flores-Lopez, F.; Young, C. A.; Tansey, M.; Yates, D.

    2010-12-01

    Potential changes in crop water demand and due to climate change is a growing concern among scientists and policy makers. In this study we analyze the potential response of evapotranspiration to climate change through the estimation of agricultural crops’ water use response to altered weather variables (temperature, precipitation, solar radiation, relative humidity, and wind speed) and an increased atmospheric CO2 concentration. Changes in growing season length, production of biomass and crop yields are also estimated through the use of downscaled climate futures selected to cover a wide range of the existing GCM results. An existing model, the Land, Air, and Water Simulator (LAWS) has been modified to include algorithms that account for the effects of altered weather variables, and the modeling of the top five agricultural crops in three representative regions of the California’s Central Valley Project System (Sacramento, San Joaquin river basin and the Delta area) is described. Study results show that atmospheric conditions can have complex and opposing influences on important evaluation metrics such as plant transpiration rates and cumulative water use, initiation and duration of the growing season, biomass production and crop yields. The magnitude of changes relative to historic conditions could be significant. Additional simulations are underway to expand the scope of the results throughout the California’s Central Valley Project System. These results will be directly relevant to the development of climate adaptation strategies effecting future Delta inflows.

  11. Elevated CO2 concentration, fertilization and their interaction: growth stimulation in a short-rotation poplar coppice (EUROFACE).

    Science.gov (United States)

    Liberloo, Marion; Dillen, Sophie Y; Calfapietra, Carlo; Marinari, Sara; Luo, Zhi Bin; De Angelis, Paolo; Ceulemans, Reinhart

    2005-02-01

    We investigated the individual and combined effects of elevated CO2 concentration and fertilization on aboveground growth of three poplar species (Populus alba L. Clone 2AS-11, P. nigra L. Clone Jean Pourtet and P. x euramericana Clone I-214) growing in a short-rotation coppice culture for two growing seasons after coppicing. Free-air carbon dioxide enrichment (FACE) stimulated the number of shoots per stool, leaf area index measured with a fish-eye-type plant canopy analyzer (LAIoptical), and annual leaf production, but did not affect dominant shoot height or canopy productivity index. Comparison of LAIoptical with LAI estimates from litter collections and from allometric relationships showed considerable differences. The increase in biomass in response to FACE was caused by an initial stimulation of absolute and relative growth rates, which disappeared after the first growing season following coppicing. An ontogenetic decline in growth in the FACE treatment, together with strong competition inside the dense plantation, may have caused this decrease. Fertilization did not influence aboveground growth, although some FACE responses were more pronounced in fertilized trees. A species effect was observed for most parameters.

  12. The impact of elevated CO2 concentration on the quality of algal starch as a potential biofuel feedstock.

    Science.gov (United States)

    Tanadul, Orn-U-Ma; VanderGheynst, Jean S; Beckles, Diane M; Powell, Ann L T; Labavitch, John M

    2014-07-01

    Cultured microalgae are viewed as important producers of lipids and polysaccharides, both of which are precursor molecules for the production of biofuels. This study addressed the impact of elevated carbon dioxide (CO2) on Chlorella sorokiniana production of starch and on several properties of the starch produced. The production of C. sorokiniana biomass, lipid and starch were enhanced when cultures were supplied with 2% CO2. Starch granules from algae grown in ambient air and 2% CO2 were analyzed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The granules from algae grown in 2% CO2 were disk-shaped and contained mainly stromal starch; granules from cultures grown in ambient air were cup-shaped with primarily pyrenoid starch. The granules from cells grown in 2% CO2 had a higher proportion of the accumulated starch as the highly branched, amylopectin glucan than did granules from cells grown in air. The rate of hydrolysis of starch from 2% CO2-grown cells was 1.25 times greater than that from air-grown cells and 2-11 times higher than the rates of hydrolysis of starches from cereal grains. These data indicate that culturing C. sorokiniana in elevated CO2 not only increases biomass yield but also improves the structure and composition of starch granules for use in biofuel generation. These modifications in culture conditions increase the hydrolysis efficiency of the starch hydrolysis, thus providing potentially important gains for biofuel production. © 2014 Wiley Periodicals, Inc.

  13. Root colonization with arbuscular mycorrhizal fungi and glomalin-related soil protein (GRSP concentration in hypoxic soils in natural CO2 springs

    Directory of Open Access Journals (Sweden)

    Irena Maček

    2012-03-01

    Full Text Available Changed ratios of soil gases that lead to hypoxia are most often present in waterlogged soils, but can also appear in soils not saturated with water. In natural CO2 springs (mofettes, gases in soil air differ from those in typical soils. In this study, plant roots from the mofette area Stavešinci (Slovenia were sampled in a spatial scale and investigated for AM fungal colonization. AM fungi were found in roots from areas with high geological CO2 concentration, however mycorrhizal intensity was relatively low and no correlation between AM fungal colonization and soil pattern of CO2/O2 concentrations (up to 37% CO2 was found. The relatively high abundance of arbuscules in root cortex indicated existence of functional symbiosis at much higher CO2 concentrations than normally found in soils. In addition, concentration of two different glomalin-related soil protein fractions – EE-GRSP and TG-GRSP – was measured. No significant correlation between any of the fractions and soil gases was found, however the concentration of both fractions was significantly higher in the upper 0–5 cm, compared to the 5–10 cm layer of the soil.

  14. [Variations of CO2 concentration and δ13C and influencing factors of Quercus variabilis plantation in low hilly area of North China].

    Science.gov (United States)

    Sun, Shou-jia; Meng, Ping; Zhang, Jin-Song; Zheng, Ning; He, Chun-xia; Li, Yan-quan

    2015-02-01

    The off-axis integrated cavity output spectroscopy technique was used to measure air CO2 concentration and stable carbon isotope ratio (δ13C) above (11 m) and at the bottom (6 m) of canopy of a Quercus variabilis plantation in a low hilly area of North China. The variations of CO2 concentration and δ13C value in Q. variabilis plantation canopy and the influencing factors were analyzed at hourly timescale. The results showed that diurnal variation in the CO2 concentration had a trend, while there was no obvious similar tendency in the diurnal change of δ13C value. Daytime atmosphere stability frequency during the experiment time was 70.2%. With the combined effects of photosynthesis and turbulent in the canopy, CO2 concentration at the bottom of canopy was 1.70 μmol · mol(-1) higher than that above the canopy, while the δ13C value was 0.81 per thousand lower than that above the canopy. Atmosphere stability frequency was 76.2% at night. The CO2 from leaf was not easy to move because of weak turbulent. Thus, CO2 concentration at the bottom of canopy was 1.24 μmol · mol(-1) higher than that above canopy, while the δ13C value was 0.58 per thousand lower than that above canopy. The difference of CO2 concentration between above and at the bottom of the canopy was strongly correlated with their δ13C difference both in daytime and at nighttime. Stepwise regression analysis indicated that solar radiation and relative humidity in daytime were the main environmental factors causing CO2 concentration and δ13C difference between above and at the bottom of the canopy, whereas at nighttime temperature was a key environmental factor influencing δ13C value. The above environmental factors strongly influenced CO2 concentration and δ13C value in air above and at the bottom of Q. variabilis plantation canopy by increasing or decreasing photosynthesis and respiration.

  15. CARVE: L2 Atmospheric CO2, CO, and CH4 Concentrations, CARVE Tower, Alaska, 2011-2015

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides atmospheric methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) dry air mole fractions and water vapor mole fractions (H2O) from...

  16. The Role of Sink Strength and Nitrogen Availability in the Down-Regulation of Photosynthetic Capacity in Field-Grown Nicotiana tabacum L. at Elevated CO2 Concentration.

    Science.gov (United States)

    Ruiz-Vera, Ursula M; De Souza, Amanda P; Long, Stephen P; Ort, Donald R

    2017-01-01

    Down-regulation of photosynthesis is among the most common responses observed in C3 plants grown under elevated atmospheric CO2 concentration ([CO2]). Down-regulation is often attributed to an insufficient capacity of sink organs to use or store the increased carbohydrate production that results from the stimulation of photosynthesis by elevated [CO2]. Down-regulation can be accentuated by inadequate nitrogen (N) supply, which may limit sink development. While there is strong evidence for down-regulation of photosynthesis at elevated [CO2] in enclosure studies most often involving potted plants, there is little evidence for this when [CO2] is elevated fully under open-air field treatment conditions. To assess the importance of sink strength on the down-regulation of photosynthesis and on the potential of N to mitigate this down-regulation under agriculturally relevant field conditions, two tobacco cultivars (Nicotiana tabacum L. cv. Petit Havana; cv. Mammoth) of strongly contrasting ability to produce the major sink of this crop, leaves, were grown under ambient and elevated [CO2] and with two different N additions in a free air [CO2] (FACE) facility. Photosynthetic down-regulation at elevated [CO2] reached only 9% in cv. Mammoth late in the season likely reflecting sustained sink strength of the rapidly growing plant whereas down-regulation in cv. Petit Havana reached 25%. Increased N supply partially mitigated down-regulation of photosynthesis in cv. Petit Havana and this mitigation was dependent on plant developmental stage. Overall, these field results were consistent with the hypothesis that sustained sink strength, that is the ability to utilize photosynthate, and adequate N supply will allow C3 crops in the field to maintain enhanced photosynthesis and therefore productivity as [CO2] continues to rise.

  17. Impact of elevated CO2 concentrations on the growth and ultrastructure of non-calcifying marine diatom (Chaetoceros gracilis F.Schütt

    Directory of Open Access Journals (Sweden)

    Hanan M. Khairy

    2014-01-01

    Full Text Available The impacts of different CO2 concentrations on the growth, physiology and ultrastructure of noncalcifying microalga Chaetoceros gracilis F.Schütt (Diatom were studied. We incubated Ch. gracilis under different CO2 concentrations, preindustrial and current ambient atmospheric concentrations (285 and 385 μatm, respectively or predicted year-2100 CO2 levels (550, 750 and 1050 μatm in continuous culture conditions. The growth of Ch. gracilis measured as cell number was decreased by increasing the pCO2 concentration from nowadays concentration (385 μatm to 1050 μatm. The lowest percentage changes of oxidizable organic matter, nitrite, nitrate, phosphate and silicate were recorded at a higher pCO2 (1050 μatm, and this is in consistence with the lowest recorded cell number indicating unsuitable conditions for the growth of Ch. gracilis. The minimum cell numbers obtained at higher levels of CO2 clearly demonstrate that, low improvement occurred when the carbon level was raised. This was confirmed by a highly negative correlation between cell number and carbon dioxide partial pressure (r = −0.742, p ⩽ 0.05. On the other hand, highest growth rate at pCO2 = 385 μatm was also confirmed by the maximum uptake of nutrient salts (NO3 = 68.96 μmol.l−1, PO4 = 29.75 μmol.l−1, Si2O3 = 36.99 μmol.l−1. Total protein, carbohydrate and lipid composition showed significant differences (p ⩽ 0.05 at different carbon dioxide concentrations during the exponential growth phase (day 8. Transmission Electron Microscopy of Ch. gracilis showed enlargement of the cell, chloroplast damage, disorganization and disintegration of thylakoid membranes; cell lysis occurs at a higher CO2 concentration (1050 μatm. It is concluded from this regression equation and from the results that the growth of Ch. gracilis is expected to decrease by increasing pCO2 and increasing ocean acidification.

  18. The effect of carbohydrate accumulation and nitrogen deficiency on feedback regulation of photosynthesis in beech (Fagus sylvatica) under elevated CO2 concentration

    Science.gov (United States)

    Klem, K.; Urban, O.; Holub, P.; Rajsnerova, P.

    2012-04-01

    One of the main manifestations of global change is an increase in atmospheric CO2 concentration. Elevated concentration of CO2 has stimulating effect on plant photosynthesis and consequently also on the productivity. Long-term studies, however, show that this effect is progressively reduced due to feedback regulation of photosynthesis. The main causes of this phenomenon are considered as two factors: i) increased biomass production consumes a larger amount of nitrogen from the soil and this leads to progressive nitrogen limitation of photosynthesis, particularly at the level of the enzyme Rubisco, ii) the sink capacity is genetically limited and elevated CO2 concentration leads to increased accumulation of carbohydtrates (mainly sucrose, which is the main transport form of assimilates) in leaves. Increased concentrations of carbohydrates leads to a feedback regulation of photosynthesis by both, long-term feedback regulation of synthesis of the enzyme Rubisco, and also due to reduced capacity to produce ATP in the chloroplasts. However, mechanisms for interactive effects of nitrogen and accumulation of non-structural carbohydrates are still not well understood. Using 3-year-old Fagus sylvatica seedlings we have explored the interactive effects of nitrogen nutrition and sink capacity manipulation (sucrose feeding) on the dynamics of accumulation of non-structural carbohydrates and changes in photosynthetic parameters under ambient (385 μmol (CO2) mol-1) and elevated (700 μmol(CO2) mol-1) CO2 concentration. Sink manipulation by sucrose feeding led to a continuous increase of non-structural carbohydrates in leaves, which was higher in nitrogen fertilized seedlings. The accumulation of non-structural carbohydrates was also slightly stimulated by elevated CO2 concentration. Exponential decay (p carbohydrates increased. However, this relationship was modified by the nitrogen content. Accumulation of non-structural carbohydrates had relatively smaller effect on actual

  19. Competition between cheatgrass and bluebunch wheatgrass is altered by temperature, resource availability, and atmospheric CO2 concentration.

    Science.gov (United States)

    Larson, Christian D; Lehnhoff, Erik A; Noffsinger, Chance; Rew, Lisa J

    2017-12-22

    Global change drivers (elevated atmospheric CO2, rising surface temperatures, and changes in resource availability) have significant consequences for global plant communities. In the northern sagebrush steppe of North America, the invasive annual grass Bromus tectorum (cheatgrass) is expected to benefit from projected warmer and drier conditions, as well as increased CO2 and nutrient availability. In growth chambers, we addressed this expectation using two replacement series experiments designed to test competition between B. tectorum and the native perennial bunchgrass Pseudoroegneria spicata. In the first experiment, we tested the effects of elevated temperature, decreased water and increased nutrient availability, on competition between the two species. In the second, we tested the effects of elevated atmospheric CO2 and decreased water availability on the competitive dynamic. In both experiments, under all conditions, P. spicata suppressed B. tectorum, though, in experiment one, warmer and drier conditions and elevated nutrient availability increased B. tectorum's competitiveness. In experiment two, when grown in monoculture, both species responded positively to elevated CO2. However, when grown in competition, elevated CO2 increased P. spicata's suppressive effect, and the combination of dry soil conditions and elevated CO2 enhanced this effect. Our findings demonstrate that B. tectorum competitiveness with P. spicata responds differently to global change drivers; thus, future conditions are unlikely to facilitate B. tectorum invasion into established P. spicata communities of the northern sagebrush steppe. However, disturbance (e.g., fire) to these communities, and the associated increase in soil nutrients, elevates the risk of B. tectorum invasion.

  20. Effect of irradiance, sucrose, and CO2 concentration on the growth of potato (Solanum tuberosum L.) in vitro

    Science.gov (United States)

    Yorio, Neil C.; Wheeler, Raymond M.; Weigel, Russell C.

    1995-01-01

    Growth measurements were taken of potato plantlets (Solanum tuberosum L.) cvs. Norland (NL), Denali (DN), and Kennebec (KN), grown in vitro. Studies were conducted in a growth chamber, with nodal explants grown for 21 days on Murashige and Skoog salts with either 0, 1, 2, or 3% sucrose and capped with loose-fitted Magenta 2-way caps that allowed approximately 2.25 air exchanges/hour. Plantlets were exposed to either 100 or 300 micro mol/sq m/s photosynthetic photon flux (PPF), and the growth chamber was maintained at either 400 or 4000 micro mol/mol CO2. Regardless of PPF, all cvs. that were grown at 4000 micro mol/mol CO2 showed significant increases in total plantlet dry weight (TDW) and shoot length (SL) when sucrose was omitted from the media, indicating an autotrophic response. At 400 micro mol/mol CO2, all cvs. showed an increase in TDW and SL with increasing sucrose under both PPF levels. Within any sucrose treatment, the highest TDW for all cvs. resulted from 300 micro mol/sq m/s PPF and 4000 micro mol/mol CO2 At 4000 micro mol/mol CO2, TDW showed no further increase with sucrose levels above 1% for cvs. NL and DN at both PPF levels, suggesting that sucrose levels greater than 1% may hinder growth when CO2 enrichment is used.

  1. Effects of rhizopheric nitric oxide (NO) on N uptake in Fagus sylvatica seedlings depend on soil CO2 concentration, soil N availability and N source.

    Science.gov (United States)

    Dong, Fang; Simon, Judy; Rienks, Michael; Lindermayr, Christian; Rennenberg, Heinz

    2015-08-01

    Rhizospheric nitric oxide (NO) and carbon dioxide (CO2) are signalling compounds known to affect physiological processes in plants. Their joint influence on tree nitrogen (N) nutrition, however, is still unknown. Therefore, this study investigated, for the first time, the combined effect of rhizospheric NO and CO2 levels on N uptake and N pools in European beech (Fagus sylvatica L.) seedlings depending on N availability. For this purpose, roots of seedlings were exposed to one of the nine combinations (i.e., low, ambient, high NO plus CO2 concentration) at either low or high N availability. Our results indicate a significant effect of rhizospheric NO and/or CO2 concentration on organic and inorganic N uptake. However, this effect depends strongly on NO and CO2 concentration, N availability and N source. Similarly, allocation of N to different N pools in the fine roots of beech seedlings also shifted with varying rhizospheric gas concentrations and N availability. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Mixed microalgae consortia growth under higher concentration of CO2from unfiltered coal fired flue gas: Fatty acid profiling and biodiesel production.

    Science.gov (United States)

    Aslam, Ambreen; Thomas-Hall, Skye R; Manzoor, Maleeha; Jabeen, Faiza; Iqbal, Munawar; Uz Zaman, Qamar; Schenk, Peer M; Asif Tahir, M

    2018-02-01

    Biodiesel is produced by transesterification of fatty acid methyl esters (FAME) from oleaginous microalgae feedstock. Biodiesel fuel properties were studied and compared with biodiesel standards. Qualitative analysis of FAME was done while cultivating mixed microalgae consortia under three concentrations of coal fired flue gas (1%, 3.0% and 5.5% CO 2 ). Under 1% CO 2 concentration (flue gas), the FAME content was 280.3 μg/mL, whereas the lipid content was 14.03 μg/mL/D (day). Both FAMEs and lipid contents were low at other CO 2 concentrations (3.0 and 5.5%). However, mixed consortia in the presence of phosphate buffer and flue gas (PB + FG) showed higher saturated fatty acids (SFA) (36.28%) and unsaturated fatty acids (UFA) (63.72%) versus 5.5% CO 2 concentration, which might be responsible for oxidative stability of biodiesel. Subsequently, higher cetane number (52) and low iodine value (136.3 gI 2 /100 g) biodiesel produced from mixed consortia (PB + FG) under 5.5% CO 2 along with 50 mM phosphate buffer were found in accordance with European (EN 14214) standard. Results revealed that phosphate buffer significantly enhanced the biodiesel quality, but reduced the FAME yield. This study intended to develop an integrated approach for significant improvement in biodiesel quality under surplus phosphorus by utilizing waste flue gas (as CO 2 source) using microalgae. The CO 2 sequestration from industrial flue gas not only reduced greenhouse gases, but may also ensure the sustainable and eco-benign production of biodiesel. Copyright © 2018. Published by Elsevier B.V.

  3. Doubling the CO2 Concentration Enhanced the Activity of Carbohydrate-Metabolism Enzymes, Source Carbohydrate Production, Photoassimilate Transport, and Sink Strength for Opuntia ficus-indica.

    Science.gov (United States)

    Wang, N.; Nobel, P. S.

    1996-03-01

    After exposure to a doubled CO2 concentration of 750 [mu]mol mol-1 air for about 3 months glucose and starch in the chlorenchyma of basal cladodes of Opuntia ficus-indica increased 175 and 57%, respectively, compared with the current CO2 concentration of 370 [mu]mol mol-1, but sucrose content was virtually unaffected. Doubling the CO2 concentration increased the nocturnal malate production in basal cladodes by 75%, inorganic phosphate (Pi) by 32%, soluble starch synthase activity by 30%, and sucrose-Pi synthase activity by 146%, but did not affect the activity of hexokinase. Doubling CO2 accelerated phloem transport of sucrose out of the basal cladodes, resulting in a 73% higher dry weight for the daughter cladodes. Doubling CO2 increased the glucose content in 14-d-old daughter cladodes by 167%, increased nocturnal malate production by 22%, decreased total amino acid content by 61%, and increased soluble starch synthase activity by 30% and sucrose synthase activity by 62%. No downward acclimation of photosynthesis during long-term exposure to elevated CO2 concentrations occurs for O. ficus-indica (M. Cui, P.M. Miller, P.S. Nobel [1993] Plant Physiol 103: 519-524; P.S. Nobel, A.A. Israel [1994] J Exp Bot 45: 295-303), consistent with its higher source capacity and sink strength than under current CO2. These changes apparently do not result in Pi limitation of photosynthesis or suppression of genes governing photosynthesis for this perennial Crassulacean acid metabolism species, as occur for some annual crops.

  4. [Effect of atmospheric CO2 concentration and nitrogen application level on absorption and transportation of nutrient elements in oilseed rape].

    Science.gov (United States)

    Wang, Wen-ming; Zhang, Zhen-hua; Song, Hai-xing; Liu, Qiang; Rong, Xiang-min; Guan, Chun-yun; Zeng, Jing; Yuan, Dan

    2015-07-01

    Effect of elevated atmospheric-CO2 (780 µmol . mol-1) on the absorption and transportation of secondary nutrient elements (calcium, magnesium, sulphur) and micronutrient elements (iron, manganese, zinc, molybdenum and boron) in oilseed rape at the stem elongation stage were studied by greenhouse simulated method. Compared with the ambient CO2 condition, the content of Zn in stem was increased and the contents of other nutrient elements were decreased under the elevated atmospheric-CO2 with no nitrogen (N) application; the contents of Ca, S, B and Zn were increased, and the contents of Mg, Mn, Mo and Fe were decreased under the elevated atmospheric CO2 with N application (0.2 g N . kg-1 soil); except the content of Mo in leaf was increased, the contents of other nutrient elements were decreased under the elevated atmospheric-CO2 with two levels of N application. Compared with the ambient CO2 condition, the amounts of Ca and S relative to the total amount of secondary nutrient elements in stem and the amounts of B and Zn relative to the total amount of micronutrient elements in stem were increased under the elevated-CO2 treatment with both levels of N application, and the corresponding values of Mg, Fe, Mn and Mo were decreased; no-N application treatment increased the proportion of Ca distributed into the leaves, and the proportion of Mg distributed into leaves was increased by the normal-N application level; the proportions of Mn, Zn and Mo distributed into the leaves were increased at both N application levels. Without N application, the elevation of atmospheric CO2 increased the transport coefficients of SFe, Mo and SS,B, but decreased the transport coefficients of SMg,Fe, SMg, Mn and SS,Fe, indicating the proportions of Mo, S transported into the upper part of plant tissues was higher than that of Fe, and the corresponding value of B was higher than that observed for S, the corresponding value of Mg was higher than that of Fe and Mn. Under normal-N application

  5. CO{sub 2} Capture by Sub-ambient Membrane Operation

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, S.; Hasse, D.; Sanders, E.; Chaubey, T.

    2012-11-30

    The main objective of the project was to develop a CO{sub 2} capture process based on sub-ambient temperature operation of a hollow fiber membrane. The program aims to reach the eventual DOE program goal of > 90% CO{sub 2} capture from existing PC fired power plants with < 35% increase in the cost of electricity. The project involves closed-loop testing of commercial fiber bundles under simulated process conditions to test the mechanical integrity and operability of membrane module structural component under sub ambient temperature. A commercial MEDAL 12” bundle exhibited excellent mechanical integrity for 2 months. However, selectivity was ~25% lower than expected at sub-ambient conditions. This could be attributed to a small feed to permeate leak or bundle non-ideality. To investigate further, and due to compressor flow limitations, the 12” bundle was replaced with a 6” bundle to conduct tests with lower permeate/feed ratios, as originally planned. The commercial 6” bundle was used for both parametric testing as well as long-term stability testing at sub-ambient conditions. Parametric studies were carried out both near the start and end of the long-term test. The parametric studies characterized membrane performance over a broad range of feed conditions: temperature (-25°C to -45°C), pressure (160 psig to 200 psig), and CO{sub 2} feed concentration (18% to 12%). Performance of the membrane bundle was markedly better at lower temperature (-45ºC), higher pressure (200 psig) and higher CO{sub 2} feed concentration (18%). The long-term test was conducted at these experimentally determined “optimum” feed conditions. Membrane performance was stable over 8 months at sub-ambient temperature operation. The experimentally measured high performance of the membrane bundle at sub-ambient operating conditions provides justification for interest in sub-ambient membrane processing of flue gas. In a parallel activity, the impact of contaminants (100 ppm SOx and NOx

  6. Spatial variability and temporal dynamics of greenhouse gas (CO2, CH4, N2O) concentrations and fluxes along the Zambezi River mainstem and major tributaries

    Science.gov (United States)

    Teodoru, C. R.; Nyoni, F. C.; Borges, A. V.; Darchambeau, F.; Nyambe, I.; Bouillon, S.

    2014-11-01

    Spanning over 3000 km in length and with a catchment of approximately 1.4 million km2, the Zambezi River is the fourth largest river in Africa and the largest flowing into the Indian Ocean from the African continent. As part of a~broader study on the riverine biogeochemistry in the Zambezi River basin, we present data on greenhouse gas (GHG, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) concentrations and fluxes collected along the Zambezi River, reservoirs and several of its tributaries during 2012 and 2013 and over two climatic seasons (dry and wet) to constrain the interannual variability, seasonality and spatial heterogeneity along the aquatic continuum. All GHGs concentrations showed high spatial variability (coefficient of variation: 1.01 for CO2, 2.65 for CH4 and 0.21 for N2O). Overall, there was no unidirectional pattern along the river stretch (i.e. decrease or increase towards the ocean), as the spatial heterogeneity of GHGs appeared to be determined mainly by the connectivity with floodplains and wetlands, and the presence of man-made structures (reservoirs) and natural barriers (waterfalls, rapids). Highest CO2 and CH4 concentrations in the mainstream river were found downstream of extensive floodplains/wetlands. Undersaturated CO2 conditions, in contrast, were characteristic for the surface waters of the two large reservoirs along the Zambezi mainstem. N2O concentrations showed the opposite pattern, being lowest downstream of floodplains and highest in reservoirs. Among tributaries, highest concentrations of both CO2 and CH4 were measured in the Shire River whereas low values were characteristic for more turbid systems such as the Luangwa and Mazoe rivers. The interannual variability in the Zambezi River was relatively large for both CO2 and CH4, and significantly higher concentrations (up to two fold) were measured during wet seasons compared to the dry season. Interannual variability of N2O was less pronounced but generally higher

  7. Two tropical conifers show strong growth and water-use efficiency responses to altered CO2 concentration.

    Science.gov (United States)

    Dalling, James W; Cernusak, Lucas A; Winter, Klaus; Aranda, Jorge; Garcia, Milton; Virgo, Aurelio; Cheesman, Alexander W; Baresch, Andres; Jaramillo, Carlos; Turner, Benjamin L

    2016-11-01

    Conifers dominated wet lowland tropical forests 100 million years ago (MYA). With a few exceptions in the Podocarpaceae and Araucariaceae, conifers are now absent from this biome. This shift to angiosperm dominance also coincided with a large decline in atmospheric CO2 concentration (ca). We compared growth and physiological performance of two lowland tropical angiosperms and conifers at ca levels representing pre-industrial (280 ppm), ambient (400 ppm) and Eocene (800 ppm) conditions to explore how differences in ca affect the growth and water-use efficiency (WUE) of seedlings from these groups. Two conifers (Araucaria heterophylla and Podocarpus guatemalensis) and two angiosperm trees (Tabebuia rosea and Chrysophyllum cainito) were grown in climate-controlled glasshouses in Panama. Growth, photosynthetic rates, nutrient uptake, and nutrient use and water-use efficiencies were measured. Podocarpus seedlings showed a stronger (66 %) increase in relative growth rate with increasing ca relative to Araucaria (19 %) and the angiosperms (no growth enhancement). The response of Podocarpus is consistent with expectations for species with conservative growth traits and low mesophyll diffusion conductance. While previous work has shown limited stomatal response of conifers to ca, we found that the two conifers had significantly greater increases in leaf and whole-plant WUE than the angiosperms, reflecting increased photosynthetic rate and reduced stomatal conductance. Foliar nitrogen isotope ratios (δ(15)N) and soil nitrate concentrations indicated a preference in Podocarpus for ammonium over nitrate, which may impact nitrogen uptake relative to nitrate assimilators under high ca SIGNIFICANCE: Podocarps colonized tropical forests after angiosperms achieved dominance and are now restricted to infertile soils. Although limited to a single species, our data suggest that higher ca may have been favourable for podocarp colonization of tropical South America 60

  8. Responses to atmospheric CO2 concentrations in crop simulation models: a review of current simple and semicomplex representations and options for model development.

    Science.gov (United States)

    Vanuytrecht, Eline; Thorburn, Peter J

    2017-05-01

    Elevated atmospheric CO2 concentrations ([CO2 ]) cause direct changes in crop physiological processes (e.g. photosynthesis and stomatal conductance). To represent these CO2 responses, commonly used crop simulation models have been amended, using simple and semicomplex representations of the processes involved. Yet, there is no standard approach to and often poor documentation of these developments. This study used a bottom-up approach (starting with the APSIM framework as case study) to evaluate modelled responses in a consortium of commonly used crop models and illuminate whether variation in responses reflects true uncertainty in our understanding compared to arbitrary choices of model developers. Diversity in simulated CO2 responses and limited validation were common among models, both within the APSIM framework and more generally. Whereas production responses show some consistency up to moderately high [CO2 ] (around 700 ppm), transpiration and stomatal responses vary more widely in nature and magnitude (e.g. a decrease in stomatal conductance varying between 35% and 90% among models was found for [CO2 ] doubling to 700 ppm). Most notably, nitrogen responses were found to be included in few crop models despite being commonly observed and critical for the simulation of photosynthetic acclimation, crop nutritional quality and carbon allocation. We suggest harmonization and consideration of more mechanistic concepts in particular subroutines, for example, for the simulation of N dynamics, as a way to improve our predictive understanding of CO2 responses and capture secondary processes. Intercomparison studies could assist in this aim, provided that they go beyond simple output comparison and explicitly identify the representations and assumptions that are causal for intermodel differences. Additionally, validation and proper documentation of the representation of CO2 responses within models should be prioritized. © 2017 John Wiley & Sons Ltd.

  9. Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil.

    Science.gov (United States)

    Liu, Dongyan; Tago, Kanako; Hayatsu, Masahito; Tokida, Takeshi; Sakai, Hidemitsu; Nakamura, Hirofumi; Usui, Yasuhiro; Hasegawa, Toshihiro; Asakawa, Susumu

    2016-09-29

    Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.

  10. The response of ecosystem water-use efficiency to rising atmospheric CO2concentrations: sensitivity and large-scale biogeochemical implications.

    Science.gov (United States)

    Knauer, Jürgen; Zaehle, Sönke; Reichstein, Markus; Medlyn, Belinda E; Forkel, Matthias; Hagemann, Stefan; Werner, Christiane

    2017-03-01

    Ecosystem water-use efficiency (WUE) is an important metric linking the global land carbon and water cycles. Eddy covariance-based estimates of WUE in temperate/boreal forests have recently been found to show a strong and unexpected increase over the 1992-2010 period, which has been attributed to the effects of rising atmospheric CO 2 concentrations on plant physiology. To test this hypothesis, we forced the observed trend in the process-based land surface model JSBACH by increasing the sensitivity of stomatal conductance (g s ) to atmospheric CO 2 concentration. We compared the simulated continental discharge, evapotranspiration (ET), and the seasonal CO 2 exchange with observations across the extratropical northern hemisphere. The increased simulated WUE led to substantial changes in surface hydrology at the continental scale, including a significant decrease in ET and a significant increase in continental runoff, both of which are inconsistent with large-scale observations. The simulated seasonal amplitude of atmospheric CO 2 decreased over time, in contrast to the observed upward trend across ground-based measurement sites. Our results provide strong indications that the recent, large-scale WUE trend is considerably smaller than that estimated for these forest ecosystems. They emphasize the decreasing CO 2 sensitivity of WUE with increasing scale, which affects the physiological interpretation of changes in ecosystem WUE. © 2016 Max Planck Institute for Biogeochemistry New Phytologist © 2016 New Phytologist Trust.

  11. Effects of CO 2 concentration and light intensity on photosynthesis of a rootless submerged plant, Ceratophyllumdemersum L., used for aquatic food production in bioregenerative life support systems

    Science.gov (United States)

    Kitaya, Y.; Okayama, T.; Murakami, K.; Takeuchi, T.

    In addition to green microalgae, aquatic higher plants are likely to play an important role in aquatic food production modules in bioregenerative systems for producing feed for fish, converting CO 2 to O 2 and remedying water quality. In the present study, the effects of culture conditions on the net photosynthetic rate of a rootless submerged plant, Ceratophyllum demersum L., was investigated to determine the optimum culture conditions for maximal function of plants in food production modules including both aquatic plant culture and fish culture systems. The net photosynthetic rate in plants was determined by the increase in dissolved O 2 concentrations in a closed vessel containing a plantlet and water. The water in the vessel was aerated sufficiently with a gas containing a known concentration of CO 2 gas mixed with N 2 gas before closing the vessel. The CO 2 concentrations in the aerating gas ranged from 0.3 to 10 mmol mol -1. Photosynthetic photon flux density (PPFD) in the vessel ranged from 0 (dark) to 1.0 mmol M -2 s -1, which was controlled with a metal halide lamp. Temperature was kept at 28°C. The net photosynthetic rate increased with increasing PPFD levels and was saturated at 0.2 and 0.5 mmol m -2 s -1 PPFD under CO 2 levels of 1.0 and 3.0 mmol mol -1, respectively. The net photosynthetic rate increased with increasing CO 2 levels from 0.3 to 3.0 mmol mol -1 showing the maximum value, 75 nmolO 2 gDW -1 s -1, at 2-3 mmol mol -1 CO 2 and gradually decreased with increasing CO 2 levels from 3.0 to 10 mmol mol -1. The results demonstrate that C. demersum could be an efficient CO 2 to O 2 converter under a 2.0 mmol mol -1 CO 2 level and relatively low PPFD levels in aquatic food production modules.

  12. Effects of CO2 concentration and light intensity on photosynthesis of a rootless submerged plant, Ceratophyllum demersum L., used for aquatic food production in bioregenerative life support systems

    Science.gov (United States)

    Kitaya, Y.; Okayama, T.; Murakami, K.; Takeuchi, T.

    2003-01-01

    In addition to green microalgae, aquatic higher plants are likely to play an important role in aquatic food production modules in bioregenerative systems for producing feed for fish, converting CO2 to O2 and remedying water quality. In the present study, the effects of culture conditions on the net photosynthetic rate of a rootless submerged plant, Ceratophyllum demersum L., was investigated to determine the optimum culture conditions for maximal function of plants in food production modules including both aquatic plant culture and fish culture systems. The net photosynthetic rate in plants was determined by the increase in dissolved O2 concentrations in a closed vessel containing a plantlet and water. The water in the vessel was aerated sufficiently with a gas containing a known concentration of CO2 gas mixed with N2 gas before closing the vessel. The CO2 concentrations in the aerating gas ranged from 0.3 to 10 mmol mol-1. Photosynthetic photon flux density (PPFD) in the vessel ranged from 0 (dark) to 1.0 mmol m-2 s-1, which was controlled with a metal halide lamp. Temperature was kept at 28 degrees C. The net photosynthetic rate increased with increasing PPFD levels and was saturated at 0.2 and 0.5 mmol m-2 s-1 PPFD under CO2 levels of 1.0 and 3.0 mmol mol-1, respectively. The net photosynthetic rate increased with increasing CO2 levels from 0.3 to 3.0 mmol mol-1 showing the maximum value, 75 nmol O2 gDW-1 s-1, at 2-3 mmol mol-1 CO2 and gradually decreased with increasing CO2 levels from 3.0 to 10 mmol mol-1. The results demonstrate that C. demersum could be an efficient CO2 to O2 converter under a 2.0 mmol mol-1 CO2 level and relatively low PPFD levels in aquatic food production modules. c2003 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  13. Determination of organ substrate oxidation in vivo by measurement of (CO2)-C-13 concentration in blood

    NARCIS (Netherlands)

    Beaufort-Krol, GCM; Takens, J; Molenkamp, MC; Smid, GB; Zijlstra, WG; Kuipers, JRG

    Substrate oxidation by various organs in animals as web is in humans is usually studied by experiments in which radioactively labeled substrates Pre used and the production of (CO2)-C-14 is measured In vivo, substrate oxidation by an organ has, up to now, not been determined by means of stable

  14. Impacts of upwind wildfire emissions on CO, CO2, and PM2.5 concentrations in Salt Lake City, Utah

    Science.gov (United States)

    D. V. Mallia; J. C. Lin; S. Urbanski; J. Ehleringer; T. Nehrkorn

    2015-01-01

    Biomass burning is known to contribute large quantities of CO2, CO, and PM2.5 to the atmosphere. Biomass burning not only affects the area in the vicinity of fire but may also impact the air quality far downwind from the fire. The 2007 and 2012 western U.S. wildfire seasons were characterized by significant wildfire...

  15. High CO2 concentration as an inductor agent to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

    Science.gov (United States)

    Ruiz, Cristina; Pla, Maria; Company, Nuri; Riudavets, Jordi; Nadal, Anna

    2016-03-01

    Cationic α-helical antimicrobial peptides such as BP100 are of increasing interest for developing novel phytosanitary or therapeutic agents and products with industrial applications. Biotechnological production of these peptides in plants can be severely impaired due to the toxicity exerted on the host by high-level expression. This can be overcome by using inducible promoters with extremely low activity throughout plant development, although the yields are limited. We examined the use of modified atmospheres using the increased levels of [CO2], commonly used in the food industry, as the inductor agent to biotechnologically produce phytotoxic compounds with higher yields. Here we show that 30% [CO2] triggered a profound transcriptional response in rice leaves, including a change in the energy provision from photosynthesis to glycolysis, and the activation of stress defense mechanisms. Five genes with central roles in up-regulated pathways were initially selected and their promoters successfully used to drive the expression of phytotoxic BP100 in genetically modified (GM) rice. GM plants had a normal phenotype on development and seed production in non-induction conditions. Treatment with 30 % [CO2] led to recombinant peptide accumulation of up to 1 % total soluble protein when the Os.hb2 promoter was used. This is within the range of biotechnological production of other peptides in plants. Using BP100 as a proof-of-concept we demonstrate that very high [CO2] can be considered an economically viable strategy to drive production of recombinant phytotoxic antimicrobial peptides in plant biofactories.

  16. Wood properties of trembling aspen and paper birch after 5 years of exposure to elevated concentrations of CO2 and O3

    Science.gov (United States)

    Katri Kostiainen; Seija Kaakinen; Elina Warsta; Mark E. Kubiske; Neil D. Nelson; Jaak Sober; David F. Karnosky; Pekka Saranpaa; Elina Vapaavuori

    2008-01-01

    We investigated the interactive effects of elevated concentrations of carbon dioxide ([CO2]) and ozone ([O3]) on radial growth, wood chemistry and structure of five 5-year-old trembling aspen (Populus tremuloides Michx.) clones and the wood chemistry of paper birch (Betula papyrifera...

  17. Effects of elevated atmospheric CO2 concentration and increased nitrogen deposition on growth and chemical composition of ombrotrophic Sphagnum balticum and oligo-mesotrophic Sphagnum papillosum

    NARCIS (Netherlands)

    Van der Heijden, E; Jauhiainen, J; Silvola, J; Vasander, H; Kuiper, PJC

    2000-01-01

    The ombrotrophic Sphagnum balticum (Russ.) C. Jens. and the oligo-mesotrophic Sphagnum papillosum Lindb. were grown at ambient (360 mu l l(-1)) and at elevated (720 mu l l(-1)) atmospheric CO2 concentrations and at different nitrogen deposition rates, varying between 0 and 30kg N ha(-1) yr(-1), The

  18. How accurately do maize crop models simulate the interactions of atmospheric CO2 concentration levels with limited water supply on water use and yield?

    Science.gov (United States)

    This study assesses the ability of 21 crop models to capture the impact of elevated CO2 concentration ([CO218 ]) on maize yield and water use as measured in a 2-year Free Air Carbon dioxide Enrichment experiment conducted at the Thünen Institute in Braunschweig, Germany (Manderscheid et al. 2014). D...

  19. The selective expression of carbonic anhydrase genes of Aspergillus nidulans in response to changes in mineral nutrition and CO2 concentration.

    Science.gov (United States)

    Xiao, Leilei; Lian, Bin; Dong, Cuiling; Liu, Fanghua

    2016-02-01

    Carbonic anhydrase (CA) plays an important role in the formation and evolution of life. However, to our knowledge, there has been no report on CA isoenzyme function differentiation in fungi. Two different CA gene sequences in Aspergillus nidulans with clear genetic background provide us a favorable basis for studying function differentiation of CA isoenzymes. Heterologously expressed CA1 was used to test its weathering ability on silicate minerals and real-time quantitative PCR was used to detect expression of the CA1 and CA2 genes at different CO2 concentrations and in the presence of different potassium sources. The northern blot method was applied to confirm the result of CA1 gene expression. Heterologously expressed CA1 significantly promoted dissolution of biotite and wollastonite, and CA1 gene expression increased significantly in response to soluble K-deficiency. The northern blot test further showed that CA1 participated in K-feldspar weathering. In addition, the results showed that CA2 was primary involved in adapting to CO2 concentration change. Taken together, A. nidulans can choose different CA to meet their survival needs, which imply that some environmental microbes have evolved different CAs to adapt to changes in CO2 concentration and acquire mineral nutrition so that they can better adapt to environmental changes. Inversely, their adaption may impact mineral weathering and/or CO2 concentration, and even global change. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  20. Impacts of elevated CO2 concentration on the productivity and surface energy budget of the soybean and maize agroecosystem in the Midwest US

    Science.gov (United States)

    The physiological response of vegetation to increasing atmospheric carbon dioxide concentration ([CO2]) modifies productivity and surface energy and water fluxes. Quantifying this response is required for assessments of future climate change. Many global climate models account for this response; how...

  1. Effect of elevated CO2 concentration and temperature on antioxidant capabilities of multiple generations of Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Li, Ning; Li, Yaohua; Zhang, Shize; Fan, Yongliang; Liu, Tongxian

    2017-10-19

    A rise in atmospheric carbon dioxide concentration ([CO2]) and a warming climate are two of the most conspicuous characteristics of global climate change in this century. However, studies addressing the combined impact of rising [CO2] and temperature on herbivore insect physiology are still limited. In this study we investigated the combined effects of elevated [CO2] and temperature on major antioxidative enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidases (POD) and detoxification enzymes of glutathione-S-transferases (GST) and acetylcholinesterase (AChE) in three consecutive generations of Bemisia tabaci Middle East-Asia Minor 1 (MEAM1, commonly known as B biotype) adults. The results indicated that the antioxidant capabilities of B. tabaci differed significantly during different treatments across different generations. Elevated [CO2] markedly increased POD, GST and AChE activities in the first generation, and SOD, CAT and GST activities in the second generation, but reduced POD activity in the third generation at ambient temperature. Under elevated temperature, elevated [CO2] significantly increased GST and AChE activities in the first generation and CAT activity in the third generation, reduced SOD activity in the third generation and reduced AChE activity in the second generation. [CO2], temperature and insect generation interacted to affect the antioxidant capabilities of B. tabaci. These results suggest both that changes in antioxidant capabilities vary in response to either [CO2] or temperature, or a combination of both, leading to oxidative stress and also that antioxidant enzymes play important roles in reducing oxidative damage in B. tabaci. Changes in the exposure of antioxidant compounds over the course of three generations suggest that acclimation and/or adaptation to elevated [CO2] and temperature may have occurred. This study represents the first comprehensive report on the antioxidant defense mechanism in successive multiple

  2. Production of Chlorella vulgaris as a source of essential fatty acids in a tubular photobioreactor continuously fed with air enriched with CO2 at different concentrations.

    Science.gov (United States)

    Ortiz Montoya, Erika Y; Casazza, Alessandro A; Aliakbarian, Bahar; Perego, Patrizia; Converti, Attilio; de Carvalho, João C Monteiro

    2014-01-01

    To reduce CO2 emissions and simultaneously produce biomass rich in essential fatty acids, Chlorella vulgaris CCAP 211 was continuously grown in a tubular photobioreactor using air alone or air enriched with CO2 as the sole carbon source. While on one hand, nitrogen-limited conditions strongly affected biomass growth, conversely, they almost doubled its lipid fraction. Under these conditions using air enriched with 0, 2, 4, 8, and 16% (v/v) CO2 , the maximum biomass concentration was 1.4, 5.8, 6.6, 6.8, and 6.4 gDB L(-1) on a dry basis, the CO2 consumption rate 62, 380, 391, 433, and 430 mgCO2 L(-1) day(-1) , and the lipid productivity 3.7, 23.7, 24.8, 29.5, and 24.4 mg L(-1) day(-1) , respectively. C. vulgaris was able to grow effectively using CO2 -enriched air, but its chlorophyll a (3.0-3.5 g 100gDB (-1) ), chlorophyll b (2.6-3.0 g 100gDB (-1) ), and lipid contents (10.7-12.0 g 100gDB (-1) ) were not significantly influenced by the presence of CO2 in the air. Most of the fatty acids in C. vulgaris biomass were of the saturated series, mainly myristic, palmitic, and stearic acids, but a portion of no less than 45% consisted of unsaturated fatty acids, and about 80% of these were high added-value essential fatty acids belonging to the ω3 and ω6 series. These results highlight that C. vulgaris biomass could be of great importance for human health when used as food additive or for functional food production. © 2014 American Institute of Chemical Engineers.

  3. Effects of elevated atmospheric CO2 concentration and temperature on the soil profile methane distribution and diffusion in rice-wheat rotation system.

    Science.gov (United States)

    Yang, Bo; Chen, Zhaozhi; Zhang, Man; Zhang, Heng; Zhang, Xuhui; Pan, Genxing; Zou, Jianwen; Xiong, Zhengqin

    2015-06-01

    The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments: ambient conditions (CKs), CO2 concentration elevated to ~500 μmol/mol (FACE), temperature elevated by ca. 2°C (T) and combined elevation of CO2 concentration and temperature (FACE+T). A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE+T and T treatments, respectively, at the 7 cm depth during the rice season (pCO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem (p<0.05). Copyright © 2015. Published by Elsevier B.V.

  4. Simultaneous effect of nitrate (NO3- concentration, carbon dioxide (CO2 supply and nitrogen limitation on biomass, lipids, carbohydrates and proteins accumulation in Nannochloropsis oculata

    Directory of Open Access Journals (Sweden)

    Aarón Millán-Oropeza

    2015-03-01

    Full Text Available Biodiesel from microalgae is a promising technology. Nutrient limitation and the addition of CO2 are two strategies to increase lipid content in microalgae. There are two different types of nitrogen limitation, progressive and abrupt limitation. In this work, the simultaneous effect of initial nitrate concentration, addition of CO2, and nitrogen limitation on biomass, lipid, protein and carbohydrates accumulation were analyzed. An experimental design was established in which initial nitrogen concentration, culture time and CO2 aeration as independent numerical variables with three levels were considered. Nitrogen limitation was taken into account as a categorical independent variable. For the experimental design, all the experiments were performed with progressive nitrogen limitation. The dependent response variables were biomass, lipid production, carbohydrates and proteins. Subsequently, comparison of both types of limitation i.e. progressive and abrupt limitation, was performed. Nitrogen limitation in a progressive mode exerted a greater effect on lipid accumulation. Culture time, nitrogen limitation and the interaction of initial nitrate concentration with nitrogen limitation had higher influences on lipids and biomass production. The highest lipid production and productivity were at 582 mgL-1 (49.7 % lipid, dry weight basis and 41.5 mgL-1d-1, respectively; under the following conditions: 250 mgL-1 of initial nitrate concentration, CO2 supply of 4% (v/v, 12 d of culturing and 2 d in state of nitrogen starvation induced by progressive limitation. This work presents a novel way to perform simultaneous analysis of the effect of the initial concentration of nitrate, nitrogen limitation, and CO2 supply on growth and lipid production of Nannochloropsis oculata, with the aim to produce potential biofuels feedstock.

  5. The rise of the photosynthetic rate when light intensity increases is delayed in ndh gene-defective tobacco at high but not at low CO2 concentrations

    Directory of Open Access Journals (Sweden)

    Mercedes eMartin

    2015-02-01

    Full Text Available The 11 plastid ndh genes have hovered frequently on the edge of dispensability, being absent in the plastid DNA of many algae and certain higher plants. We have compared the photosynthetic activity of tobacco (Nicotiana tabacum, cv. Petit Havana with five transgenic lines (ndhF, pr-ndhF, T181D, T181A and ndhF FC and found that photosynthetic performance is impaired in transgenic ndhF-defective tobacco plants at rapidly fluctuating light intensities and higher than ambient CO2 concentrations. In contrast to wild type and ndhF FC, which reach the maximum photosynthetic rate in less than one min when light intensity suddenly increases, ndh defective plants (ndhF and T181A show up to a 5 min delay in reaching the maximum photosynthetic rate at CO2 concentrations higher than the ambient 360 ppm. Net photosynthesis was determined at different CO2 concentrations when sequences of 130, 870, 61, 870 and 130 μmol m−2 s−1 PAR sudden light changes were applied to leaves and photosynthetic efficiency and entropy production were determined as indicators of photosynthesis performance. The two ndh-defective plants, ndhF and T181A, had lower photosynthetic efficiency and higher entropy production than wt, ndhF FC and T181D tobacco plants, containing full functional ndh genes, at CO2 concentrations above 400 ppm. We propose that the Ndh complex improves cyclic electron transport by adjusting the redox level of transporters during the low light intensity stage. In ndhF-defective strains, the supply of electrons through the Ndh complex fails, transporters remain over-oxidized (specially at high CO2 concentrations and the rate of cyclic electron transport is low, impairing the ATP level required to rapidly reach high CO2 fixation rates in the following high light phase. Hence, ndh genes could be dispensable at low but not at high atmospheric concentrations of CO2.

  6. The rise of the photosynthetic rate when light intensity increases is delayed in ndh gene-defective tobacco at high but not at low CO2 concentrations.

    Science.gov (United States)

    Martín, Mercedes; Noarbe, Dolores M; Serrot, Patricia H; Sabater, Bartolomé

    2015-01-01

    The 11 plastid ndh genes have hovered frequently on the edge of dispensability, being absent in the plastid DNA of many algae and certain higher plants. We have compared the photosynthetic activity of tobacco (Nicotiana tabacum, cv. Petit Havana) with five transgenic lines (ΔndhF, pr-ΔndhF, T181D, T181A, and ndhF FC) and found that photosynthetic performance is impaired in transgenic ndhF-defective tobacco plants at rapidly fluctuating light intensities and higher than ambient CO2 concentrations. In contrast to wild type and ndhF FC, which reach the maximum photosynthetic rate in less than 1 min when light intensity suddenly increases, ndh defective plants (ΔndhF and T181A) show up to a 5 min delay in reaching the maximum photosynthetic rate at CO2 concentrations higher than the ambient 360 ppm. Net photosynthesis was determined at different CO2 concentrations when sequences of 130, 870, 61, 870, and 130 μmol m(-2) s(-1) PAR sudden light changes were applied to leaves and photosynthetic efficiency and entropy production (Sg) were determined as indicators of photosynthesis performance. The two ndh-defective plants, ΔndhF and T181A, had lower photosynthetic efficiency and higher Sg than wt, ndhF FC and T181D tobacco plants, containing full functional ndh genes, at CO2 concentrations above 400 ppm. We propose that the Ndh complex improves cyclic electron transport by adjusting the redox level of transporters during the low light intensity stage. In ndhF-defective strains, the supply of electrons through the Ndh complex fails, transporters remain over-oxidized (specially at high CO2 concentrations) and the rate of cyclic electron transport is low, impairing the ATP level required to rapidly reach high CO2 fixation rates in the following high light phase. Hence, ndh genes could be dispensable at low but not at high atmospheric concentrations of CO2.

  7. Development of an innovative decentralized treatment system for the reclamation and reuse of strong wastewater from rural community: Effects of elevated CO2 concentrations.

    Science.gov (United States)

    Chen, Xiaochen; Fukushi, Kensuke

    2016-09-15

    In a previous study, a soil-plant-based natural treatment system was successfully developed for post-treatment of anaerobically digested strong wastewater full of potential nutrients (nitrogen, phosphorus, and potassium). For upgraded performance, an innovative decentralized treatment system was further developed, in which an anaerobic digestion stage and a natural treatment system stage are placed within a greenhouse. This allows the CO2 generated by the processing of wastewater and biogas consumption to be sequestrated within the greenhouse for elevating its concentration level and potentially enhance nutrient removal and recovery from the applied wastewater. To investigate the feasibility of the system, a bench-scale experiment was conducted using CO2 chambers. Valuable Kentucky bluegrass was planted in two soil types (red ball earth and black soil) at three CO2 concentrations (340 ppm, 900 ppm, and 1400 ppm). The results confirmed the positive effects of elevated CO2 concentration on the biomass production and turf quality of Kentucky bluegrass as well as the resulting higher nutrient recovery efficiencies. More importantly, it was demonstrated that the elevated CO2 concentration significantly stimulated the soil nitrifying microorganisms and thus improved the nitrogen removal efficiency (a critical issue in ecological wastewater treatment). A CO2 concentration of 1400 ppm is therefore recommended for use in the system. The mechanism underlying this phenomenon was shown to be an indirect effect, in which the higher CO2 concentration first positively influenced growing plants, which then stimulated the soil nitrifier communities. The effects of soil type (a design parameter) and hydraulic and nutrient loading rates (an operational parameter) on system performance were also examined. The results favored black soil for system establishment. Based on the findings of this study, our proposed system is thought to have the potential to be scaled up and adopted by

  8. Determination of H2O and CO2 concentrations in fluid inclusions in minerals using laser decrepitation and capacitance manometer analysis

    Science.gov (United States)

    Yonover, R. N.; Bourcier, W. L.; Gibson, E. K.

    1985-01-01

    Water and carbon dioxide concentrations within individual and selected groups of fluid inclusions in quartz were analyzed by using laser decrepitation and quantitative capacitance manometer determination. The useful limit of detection (calculated as ten times the typical background level) is about 5 x 10(-10) mol of H2O and 5 x 10(-11) mol of CO2; this H2O content translates into an aqueous fluid inclusion approximately 25 micrometers in diameter. CO2/H2O determinations for 38 samples (100 separate measurements) have a range of H2O amounts of 5.119 x 10(-9) to 1.261 x 10(-7) mol; CO2 amounts of 7.216 x 10(-10) to 1.488 x 10(-8) mol, and CO2/H2O mole ratios of 0.011 to 1.241. Replicate mole ratio determinations of CO2/H2O for three identical (?) clusters of inclusions in quartz have average mole ratios of 0.0305 +/- 0.0041 1 sigma. Our method offers much promise for analysis of individual fluid inclusions, is sensitive, is selective when the laser energy is not so great as to melt the mineral (laser pits approximately 50 micrometers in diameter), and permits rapid analysis (approximately 1 h per sample analysis).

  9. Evidence for a Role for NAD(P)H Dehydrogenase in Concentration of CO2 in the Bundle Sheath Cell of Zea mays.

    Science.gov (United States)

    Peterson, Richard B; Schultes, Neil P; McHale, Neil A; Zelitch, Israel

    2016-05-01

    Prior studies with Nicotiana and Arabidopsis described failed assembly of the chloroplastic NDH [NAD(P)H dehydrogenase] supercomplex by serial mutation of several subunit genes. We examined the properties of Zea mays leaves containing Mu and Ds insertions into nuclear gene exons encoding the critical o- and n-subunits of NDH, respectively. In vivo reduction of plastoquinone in the dark was sharply diminished in maize homozygous mutant compared to normal leaves but not to the extreme degree observed for the corresponding lesions in Arabidopsis. The net carbon assimilation rate (A) at high irradiance and saturating CO2 levels was reduced by one-half due to NDH mutation in maize although no genotypic effect was evident at very low CO2 levels. Simultaneous assessment of chlorophyll fluorescence and A in maize at low (2% by volume) and high (21%) O2 levels indicated the presence of a small, yet detectable, O2-dependent component of total linear photosynthetic electron transport in 21% O2 This O2-dependent component decreased with increasing CO2 level indicative of photorespiration. Photorespiration was generally elevated in maize mutant compared to normal leaves. Quantification of the proportion of total electron transport supporting photorespiration enabled estimation of the bundle sheath cell CO2 concentration (Cb) using a simple kinetic model of ribulose bisphosphate carboxylase/oxygenase function. The A versus Cb relationships overlapped for normal and mutant lines consistent with occurrence of strictly CO2-limited photosynthesis in the mutant bundle sheath cell. The results are discussed in terms of a previously reported CO2 concentration model [Laisk A, Edwards GE (2000) Photosynth Res 66: 199-224]. © 2016 American Society of Plant Biologists. All Rights Reserved.

  10. Response of photosynthesis in the leaves of cucumber seedlings to light intensity and CO2 concentration under nitrate stress

    OpenAIRE

    Yang, Xiaoyu; Wang, Xiufeng; Wei, Min

    2014-01-01

    The effects of 2 nitrate levels, 14 (CK) and 140 mmol L-1 (T), on the leaf gas exchange variables of cucumber (Cucumis sativus L. cv. Xintaimici) seedlings grown in hydroponic culture were investigated. Photosynthetic light- and CO2-response curves from CK and T seedlings were determined and used for the analysis of photosynthetic capacity. The results showed that nitrate stress resulted in a significant reduction of net photosynthesis of T seedlings compared with CK. At the same time, the ap...

  11. Temperature and atmospheric CO2 concentration estimates through the PETM using triple oxygen isotope analysis of mammalian bioapatite.

    Science.gov (United States)

    Gehler, Alexander; Gingerich, Philip D; Pack, Andreas

    2016-07-12

    The Paleocene-Eocene Thermal Maximum (PETM) is a remarkable climatic and environmental event that occurred 56 Ma ago and has importance for understanding possible future climate change. The Paleocene-Eocene transition is marked by a rapid temperature rise contemporaneous with a large negative carbon isotope excursion (CIE). Both the temperature and the isotopic excursion are well-documented by terrestrial and marine proxies. The CIE was the result of a massive release of carbon into the atmosphere. However, the carbon source and quantities of CO2 and CH4 greenhouse gases that contributed to global warming are poorly constrained and highly debated. Here we combine an established oxygen isotope paleothermometer with a newly developed triple oxygen isotope paleo-CO2 barometer. We attempt to quantify the source of greenhouse gases released during the Paleocene-Eocene transition by analyzing bioapatite of terrestrial mammals. Our results are consistent with previous estimates of PETM temperature change and suggest that not only CO2 but also massive release of seabed methane was the driver for CIE and PETM.

  12. 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.

  13. Effect of the temperature and the CO2 concentration on the behaviour of the citric acid as a scale inhibitor of CaCO3

    Science.gov (United States)

    Blanco, K.; Aponte, H.; Vera, E.

    2017-12-01

    For all Industrial sector is important to extend the useful life of the materials that they use in their process, the scales of CaCO3 are common in situation where fluids are handled with high concentration of ions and besides this temperatures and CO2 concentration dissolved, that scale generates large annual losses because there is a reduction in the process efficiency or corrosion damage under deposit, among other. In order to find new alternatives to this problem, the citric acid was evaluated as scale of calcium carbonate inhibition in critical condition of temperature and concentration of CO2 dissolved. Once the results are obtained it was carried out the statistical evaluation in order to generate an equation that allow to see that behaviour, giving as result, a good efficiency of inhibition to the conditions evaluated the scales of products obtained were characterized through scanning electron microscopy.

  14. Effects of temperature, CO2/O2 concentrations and light intensity on cellular prolification of microalgae, eugrena gracilis, in aquatic food production of bioregenerative life support systems

    Science.gov (United States)

    Kitaya, Y.; Azuma, H.; Kiyota, M.

    Microalgae are likely to play an important role in aquatic food production modules in bioregenerative systems for producing feeds for fish, converting CO_2 to O_2 and remedying water quality as well as aquatic higher plants. In the present study, the effects of culture conditions on the cellular proliferation of microalgae, Eugrena gracilis, was investigated to determine the optimum culture conditions for microalgae production in aquatic food production modules including both microalgae culture and fish culture systems. E. gracilis was cultured under conditions with five levels of temperature (25-33°C), three levels of CO_2 concentration (2-6%), four levels of O_2 concentration (10-25%), and three levels of photosynthetic photon flux density (50-120 μmol m-2 s-1). The number of Eugrena cells in a certain volume of solution was monitored with a microscope under each environment. The multiplication rate of the cells was highest at temperatures of 29°C, 4% CO_2, 20% O_2 and 90 μmol m-2 s-1 PPFD. The results demonstrate that E. gracilis could efficiently produce biomass and convert CO_2 to O_2 under relatively low light intensities in aquatic food production modules.

  15. Influence of atmospheric [CO2] on growth, carbon allocation and cost of plant tissues on leaf nitrogen concentration maintenance in nodulated Medicago sativa

    Science.gov (United States)

    Pereyra, Gabriela; Hartmann, Henrik; Ziegler, Waldemar; Michalzik, Beate; Gonzalez-Meler, Miquel; Trumbore, Susan

    2015-04-01

    Plant carbon (C) allocation and plant metabolic processes (i.e. photosynthesis and respiration) can be affected by changes in C availability, for example from changing atmospheric [CO2]. In nodulated plants, C availability may also influence nitrogen (N) fixation by bacteriods. But C allocation and N fixation are often studied independently and hence do not allow elucidating interactive effects. We investigated how different atmospheric [CO2] (Pleistocene: 170 ppm, ambient: 400 ppm and projected future: 700 ppm) influence plant growth, allocation to nodules, and the ratio of photosynthesis-to-respiration (R:A) as an indicator of C cost in Medicago sativa inoculated with Ensifer meliloti. M. sativa grew c. 38% more nodules at 400 ppm and 700 ppm than at 170 ppm. However, ratios of above- and belowground plant biomass to nodule biomass were constant over time and independent of atmospheric [CO2]. Total non-structural carbohydrate concentrations were not significantly different between plants grown at 400 and 700 ppm, but were four to five-fold higher than in 170 ppm plants. Leaf level N concentration was similar across treatments, but N-based photosynthetic rates were 82% and 93% higher in leaves of plants grown at 400 and 700 ppm, respectively, than plants grown at 170 ppm. In addition, leaf R:A was greater (48% or 55%) in plants grown at 170 ppm than plants grown at 400 and 700 ppm. Similarly, the greatest proportion of assimilated CO2 released by root respiration occurred in rhizobial plants growing at 170 ppm. Our results suggest that C limitation in nodulated Medicago sativa plants did not influence C allocation to nodule biomass but caused a proportionally greater allocation of C to belowground respiration, most likely to bacteriods. This suggests that N tissue concentration was maintained at low [CO2] by revving up bacteriod metabolism and at the expense of non-structural carbohydrate reserves.

  16. Aspartic acid as an internal CO2 reservoir in Zea mays: Effect of oxygen concentration and of far-red illumination.

    Science.gov (United States)

    Créach, E; Michel, J P; Thibault, P

    1974-06-01

    By placing leaf segments first in CO2 in the dark, then in pure nitrogen either in the dark and afterwards in the light or immediately in the light, the existence of internal CO2 pools which can be used for photosynthesis had been demonstrated. In Zea mays L. there are two such pools: one which in the absence of any energy source is short-lived (t1/2 ca. 2 min), and another which is relatively long-lived (t1/2 ca. 50 min).Under different oxygen concentrations the level of the short-lived CO2 pool exibited a parallel variation with the level of aspartic acid. Only a fraction of the total aspartic acid (60%) constituted the active pool, the quantity of which was equal to the short-lived CO2. In the absence of O2 but under far-red irradiation (maximum 740 nm), a net synthesis of aspartic acid was observed; its extent depended on the intensity of the light.The similarity in the response to O2 and to long-wavelength irradiation suggests that aspartate synthesis is regulated by ATP, the high-energy compound common to both oxidative and cyclic phosphorylations. The formation of aspartic acid observed in the dark under N2+1% CO2 immediately following illumination under pure N2 suggests use of ATP accumulated in the preceding light period, in aspartate synthesis.Even though Zea mays is predominantly a "malate former", it appears that aspartate must also be considered as a readily available donor of CO2 since, when aspartate is present, O2 release is always immediate while, when it is not, O2 release is delayed.

  17. Accelerating carbon uptake in the Northern Hemisphere: evidence from the interhemispheric difference of atmospheric CO2 concentrations

    Directory of Open Access Journals (Sweden)

    Yuxuan Wang

    2013-11-01

    Full Text Available Previous studies have indicated that the regression slope between the interhemispheric difference (IHD of CO2 mixing ratios and fossil fuel (FF CO2 emissions was rather constant at about 0.5 ppm/Pg C yr−1 during 1957–2003. In this study, we found that the average regression slopes between the IHD of CO2 mixing ratios and IHD of FF emissions for 16 sites in the Northern Hemisphere (NH decreased from 0.69±0.12 ppm/Pg C yr−1 during 1982–1991 to 0.37±0.06 ppm/Pg C yr−1 during 1996–2008 (IHD of CO2 defined as the differences between each site and the South Pole, SPO. The largest difference was found in summer and autumn. The change in the spatial distribution of FF emissions driven by fast increasing Asian emissions may explain the slope change at three sites located north of 60°N but not at the other sites. A 30-yr SF6 simulation with time-varying meteorology and constant emissions suggests no significant difference in the decadal average and seasonal variation of interhemispheric exchange time (τ ex between the two periods. Based on the hemispheric net carbon fluxes derived from a two-box model, we attributed 75% of the regression slope decrease at NH sites south of 60°N to the acceleration of net carbon sink increase in the NH and 25% to the weakening of net carbon sink increase in the SH during 1996–2008. The growth rate of net carbon sink in the NH has increased by a factor of about three from 0.028±0.023 [mean±2σ] Pg C yr−2 during 1982–1991 to 0.093±0.033 Pg C yr−2 during 1996–2008, exceeding the percentage increase in the growth rate of IHD of FF emissions between the two periods (45%. The growth rate of net carbon sink in the SH has reduced 62% from 0.058±0.018 Pg C yr−2 during 1982–1991 to 0.022±0.012 Pg C yr−2 during 1996–2008.

  18. Dissolved organic carbon, CO2, and CH4 concentrations and their stable isotope ratios in thermokarst lakes on the Qinghai-Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Cuicui Mu

    2016-01-01

    Full Text Available Thermokarst lakes are widely distributed on the Qinghai-Tibetan Plateau (QTP, which accounts for 8% of the global permafrost area. These lakes probably promote organic matter biodegradation and thus accelerate the emission of carbon-based greenhouse gases. However, little is known about greenhouse gas concentrations and their stable isotopes characteristics of these lakes. In this study, we measured the concentrations of dissolved organic carbon (DOC, dissolved CO2 and CH4, as well as the distribution of δ13CCO2, δ13CCH4, and δ13COM (organic matter of lake sediments in thermokarst lakes on the QTP. Results showed that the OM of the lake sediments was highly decomposed. The concentrations of DOC, CO2 and CH4 in the lake water on the QTP were 1.2–49.6 mg L–1, 3.6–45.0 μmol L–1 and 0.28–3.0 μmol L–1, respectively. The highest CO2 and CH4 concentrations were recorded in July while the lowest values in September, which suggested that temperature had an effect on greenhouse gas production, although this pattern may also relate to thermal stratification of the water column. The results implied that thermokast lakes should be paid more attention to regarding carbon cycle and greenhouse gas emissions on the QTP.

  19. Decadal changes in atmospheric CO 2 concentration and δ 13C over two seas and two oceans: Italy to New Zealand

    Science.gov (United States)

    Longinelli, Antonio; Lenaz, Renzo; Ori, Carlo; Langone, Leonardo; Selmo, Enricomaria; Giglio, Federico

    2010-11-01

    Continuous measurements of the CO 2 concentration were repeatedly carried out from 1996 to 2007 between Italy and New Zealand by means of a Siemens Ultramat 5E analyzer assembled for shipboard use. Along the ship routes discrete air samples were collected from 1998 to 2005 using four-litre Pyrex flasks. The δ 13C of the CO 2 from the flask air samples was measured according to well-established techniques. The decadal changes of these two variables can now be evaluated from these results. Large variations of the CO 2 concentration were normally recorded in the Mediterranean and the Red Sea. Completely different trends of the CO 2 concentration were observed in the Red Sea (30° N to about 13° N) between 2007 (a marked southward decrease) and 2005 and 2003 when a marked southward increase is apparent, at least between 23° and 13° N. A further difference among different expeditions is related to the decrease or increase of the CO 2 concentration in the Gulf of Aden. The backward trajectories of the air masses help to explain, at least partially, these differences. In the Indian Ocean and Southern Ocean a decrease of a few ppmv of the CO 2 concentration takes place from Cape Guardafui (Northern Somaliland) to southern New Zealand, particularly during 2005 and 2007. The yearly rate of increase of the CO 2 concentration between 1996 and 2007 for the Indian Ocean is of about 1.9 ppmv yr -1, in excellent agreement with the NOAA/CMDL measurements carried out during the same period at Mahé Isld. (Indian Ocean) and Cape Grim (Tasmania). The δ 13C results obtained from the CO 2 of flask samples collected in the Mediterranean show the effect of anthropogenic emissions, though this is considerably smaller than expected. This inconsistency may be related to the large terrestrial biospheric sink of CO 2 in the Northern Hemisphere. The results obtained from the Red Sea are quite variable through time and space, particularly in its southern section; their interpretation is not

  20. Five-years of microenvironment data along an urban-rural transect; temperature and CO2 concentrations in urban area at levels expected globally with climate change.

    Energy Technology Data Exchange (ETDEWEB)

    George, Kate; Ziska, Lewis H; Bunce, James A; Quebedeaux, Bruno

    2007-11-01

    The heat island effect and the high use of fossil fuels in large city centers is well documented, but by how much fossil fuel consumption is elevating atmospheric CO2 concentrations and whether elevations in both atmospheric CO2 and air temperature are consistent from year to year are less well known. Our aim was to record atmospheric CO2 concentrations, air temperature and other environmental variables in an urban area and compare it to suburban and rural sites to see if urban sites are experiencing climates expected globally in the future with climate change. A transect was established from Baltimore city center (Urban site), to the outer suburbs of Baltimore (suburban site) and out to an organic farm (rural site). At each site a weather station was set-up to monitor environmental variables annually for five years. Atmospheric CO2 was significantly increased on average by 66 ppm from the rural to the urban site over the five years of the study. Air temperature was significantly higher at the urban site (14.8 oC) compared to the suburban (13.6 oC) and rural (12.7 oC) sites. Relative humidity was not different between sites but vapor pressure deficit (VPD) was significantly higher at the urban site compared to the suburban and rural sites. During wet years relative humidity was significantly increased and VPD significantly reduced. Increased nitrogen deposition at the rural site (2.1 % compared to 1.8 and 1.2 % at the suburban and urban sites) was small enough not to affect soil nitrogen content. Dense urban areas with large populations and high vehicular traffic have significantly different microclimates compared to outlying suburban and rural areas. The increases in atmospheric CO2 and air temperature are similar to changes predicted in the short term with global climate change, therefore providing an environment suitable for studying future effects of climate change on terrestrial ecosystems.

  1. Gas-phase CO2 subtraction for improved measurements of the organic aerosol mass concentration and oxidation degree by an aerosol mass spectrometer.

    Science.gov (United States)

    Collier, S; Zhang, Q

    2013-12-17

    The Aerodyne aerosol mass spectrometer (AMS) has been widely used for real-time characterization of the size-resolved chemical composition of sub-micrometer aerosol particles. The first step in AMS sampling is the pre-concentration of aerosols while stripping away the gas-phase components, which contributes to the high sensitivity of this instrument. The strength of the instrument lies in particle phase measurement; however, ion signals generated from gas-phase species can influence the interpretation of the particle-phase chemistry data. Here, we present methods for subtracting the varying contributions of gas-phase carbon dioxide (CO2) in the AMS spectra of aerosol particles, which is critical for determining the mass concentration and oxygen-to-carbon (O/C) ratio of organic aerosol. This report gives details on the gaseous CO2 subtraction analysis performed on a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) data set acquired from sampling of fresh and diluted vehicle emissions. Three different methods were used: (1) collocated continuous gas-phase CO2 measurement coupled with periodic filter tests consisting of sampling the same particle-free air by the AMS and the CO2 analyzer, (2) positive matrix factorization (PMF) analysis to separate the gas- and particle-phase signals of CO2(+) at m/z 44, and (3) use of the particle time-of-flight (PTOF) size-resolved chemical information for separation of gas- and particle-phase signals at m/z 44. Our results indicate that these three different approaches yield internally consistent values for the gas/particle apportionment of m/z 44, but methods 2 and 3 require certain conditions to be met to yield reliable results. The methods presented are applicable to any situation where gas-phase components may influence the PM signal of interest.

  2. Elevated atmospheric CO2 concentration ameliorates effects of NaCl salinity on photosynthesis and leaf structure of Aster tripolium L.

    Science.gov (United States)

    Geissler, Nicole; Hussin, Sayed; Koyro, Hans-Werner

    2009-01-01

    This study investigated the interaction of NaCl-salinity and elevated atmospheric CO2 concentration on gas exchange, leaf pigment composition, and leaf ultrastructure of the potential cash crop halophyte Aster tripolium. The plants were irrigated with five different salinity levels (0, 25, 50, 75, 100% seawater salinity) under ambient and elevated (520 ppm) CO2. Under saline conditions (ambient CO2) stomatal and mesophyll resistance increased, leading to a significant decrease in photosynthesis and water use efficiency (WUE) and to an increase in oxidative stress. The latter was indicated by dilations of the thylakoid membranes and an increase in superoxide dismutase (SOD) activity. Oxidative stress could be counteracted by thicker epidermal cell walls of the leaves, a thicker cuticle, a reduced chlorophyll content, an increase in the chlorophyll a/b ratio and a transient decline of the photosynthetic efficiency. Elevated CO2 led to a significant increase in photosynthesis and WUE. The improved water and energy supply was used to increase the investment in mechanisms reducing water loss and oxidative stress (thicker cell walls and cuticles, a higher chlorophyll and carotenoid content, higher SOD activity), resulting in more intact thylakoids. As these mechanisms can improve survival under salinity, A. tripolium seems to be a promising cash crop halophyte which can help in desalinizing and reclaiming degraded land. PMID:19036838

  3. Recent and projected increases in atmospheric CO2 concentration can enhance gene flow between wild and genetically altered rice (Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Lewis H Ziska

    Full Text Available Although recent and projected increases in atmospheric carbon dioxide can alter plant phenological development, these changes have not been quantified in terms of floral outcrossing rates or gene transfer. Could differential phenological development in response to rising CO(2 between genetically modified crops and wild, weedy relatives increase the spread of novel genes, potentially altering evolutionary fitness? Here we show that increasing CO(2 from an early 20(th century concentration (300 µmol mol(-1 to current (400 µmol mol(-1 and projected, mid-21(st century (600 µmol mol(-1 values, enhanced the flow of genes from wild, weedy rice to the genetically altered, herbicide resistant, cultivated population, with outcrossing increasing from 0.22% to 0.71% from 300 to 600 µmol mol(-1. The increase in outcrossing and gene transfer was associated with differential increases in plant height, as well as greater tiller and panicle production in the wild, relative to the cultivated population. In addition, increasing CO(2 also resulted in a greater synchronicity in flowering times between the two populations. The observed changes reported here resulted in a subsequent increase in rice dedomestication and a greater number of weedy, herbicide-resistant hybrid progeny. Overall, these data suggest that differential phenological responses to rising atmospheric CO(2 could result in enhanced flow of novel genes and greater success of feral plant species in agroecosystems.

  4. Parthenium weed (Parthenium hysterophorus L.) and climate change: the effect of CO2concentration, temperature, and water deficit on growth and reproduction of two biotypes.

    Science.gov (United States)

    Nguyen, Thi; Bajwa, Ali Ahsan; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

    2017-04-01

    Climate change will have a considerable impact upon the processes that moderate weed invasion, in particular to that of parthenium weed (Parthenium hysterophorus L.). This study evaluated the performance of two Australian biotypes of parthenium weed under a range of environmental conditions including soil moisture (100 and 50% of field capacity), atmospheric carbon dioxide (CO 2 ) concentration (390 and 550 ppm), and temperature (35/20 and 30/15 °C/day/night). Measurements were taken upon growth, reproductive output, seed biology (fill, viability and dormancy) and soil seed longevity. Parthenium weed growth and seed output were significantly increased under the elevated CO 2 concentration (550 ppm) and in the cooler (30/15 °C) and wetter (field capacity) conditions. However, elevated CO 2 concentration could not promote growth or seed output when the plants were grown under the warmer (35/20 °C) and wetter conditions. Warm temperatures accelerated the growth of parthenium weed, producing plants with greater height biomass but with a shorter life span. Warm temperatures also affected the reproductive output by promoting both seed production and fill, and promoting seed longevity. Dryer soil conditions (50% of field capacity) also promoted the reproductive output, but did not retain high seed fill or promote seed longevity. Therefore, the rising temperatures, the increased atmospheric CO 2 concentration and the longer periods of drought predicted under climate change scenarios are likely to substantially enhance the growth and reproductive output of these two Australian parthenium weed biotypes. This may facilitate the further invasion of this noxious weed in tropical and sub-tropical natural and agro-ecosystems.

  5. [Effect of carbon substrate concentration on N2, N2O, NO, CO2, and CH4 emissions from a paddy soil in anaerobic condition].

    Science.gov (United States)

    Chen, Nuo; Liao, Ting-ting; Wang, Rui; Zheng, Xun-hua; Hu, Rong-gui; Butterbach-Bahl, Klaus

    2014-09-01

    Understanding the effects of carbon and nitrogen substrates concentrations on the emissions of denitrification gases including nitrogen (N2) , nitrous oxide (N2O) and nitric oxide (NO), carbon dioxide (CO2) and methane (CH4) from anaerobic paddy soils is believed to be helpful for development of greenhouse gas mitigation strategies. Moreover, understanding the quantitative dependence of denitrification products compositions on carbon substrate concentration could provide some key parameters or parameterization scheme for developing process-oriented model(s) of nitrogen transformation. Using a silt loam soil collected from a paddy field, we investigated the influence of carbon substrate concentration on the emissions of the denitrification gases, CO2 and CH4 from anaerobically incubated soils by setting two treatments: control (CK) with initial soil nitrate and dissolved organic carbon (DOC) concentrations of ~ 50 mg.kg-1 and -28 mg kg-1 , respectively; and DOC added (C + ) with initial soil nitrate and DOC concentrations of ~50 mg.kg-1 and ~300 mg.kg-1 , respectively. The emissions of denitrification gases, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each treatment were dynamically measured, using the gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that CH4 emission was not observed in CK treatment while observed in C treatment. Aggregate emission of greenhouse gases for C + treatment was significantly higher comparing with the CK treatment (P substrate concentrations can significantly change the composition of nitrogen gas emissions. The results also implicated that organic fertilizer should not be applied to nitrate-rich paddy soils prior to or during flooding so as to mitigate greenhouse gases emissions.

  6. Interaction of CO2 concentrations and water stress in semiarid plants causes diverging response in instantaneous water use efficiency and carbon isotope composition

    Science.gov (United States)

    Zhao, Na; Meng, Ping; He, Yabing; Yu, Xinxiao

    2017-07-01

    In the context of global warming attributable to the increasing levels of CO2, severe drought may be more frequent in areas that already experience chronic water shortages (semiarid areas). This necessitates research on the interactions between increased levels of CO2 and drought and their effect on plant photosynthesis. It is commonly reported that 13C fractionation occurs as CO2 gas diffuses from the atmosphere to the substomatal cavity. Few researchers have investigated 13C fractionation at the site of carboxylation to cytoplasm before sugars are exported outward from the leaf. This process typically progresses in response to variations in environmental conditions (i.e., CO2 concentrations and water stress), including in their interaction. Therefore, saplings of two typical plant species (Platycladus orientalis and Quercus variabilis) from semiarid areas of northern China were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentration ([CO2]) × five soil volumetric water content (SWC)). The δ13C of water-soluble compounds extracted from leaves of saplings was determined for an assessment of instantaneous water use efficiency (WUEcp) after cultivation. Instantaneous water use efficiency derived from gas-exchange measurements (WUEge) was integrated to estimate differences in δ13C signal variation before leaf-level translocation of primary assimilates. The WUEge values in P. orientalis and Q. variabilis both decreased with increased soil moisture at 35-80 % of field capacity (FC) and increased with elevated [CO2] by increasing photosynthetic capacity and reducing transpiration. Instantaneous water use efficiency (iWUE) according to environmental changes differed between the two species. The WUEge in P. orientalis was significantly greater than that in Q. variabilis, while an opposite tendency was observed when comparing WUEcp between the two species. Total 13C fractionation at the site of carboxylation to cytoplasm before sugar

  7. Interaction of CO2 concentrations and water stress in semiarid plants causes diverging response in instantaneous water use efficiency and carbon isotope composition

    Directory of Open Access Journals (Sweden)

    N. Zhao

    2017-07-01

    Full Text Available In the context of global warming attributable to the increasing levels of CO2, severe drought may be more frequent in areas that already experience chronic water shortages (semiarid areas. This necessitates research on the interactions between increased levels of CO2 and drought and their effect on plant photosynthesis. It is commonly reported that 13C fractionation occurs as CO2 gas diffuses from the atmosphere to the substomatal cavity. Few researchers have investigated 13C fractionation at the site of carboxylation to cytoplasm before sugars are exported outward from the leaf. This process typically progresses in response to variations in environmental conditions (i.e., CO2 concentrations and water stress, including in their interaction. Therefore, saplings of two typical plant species (Platycladus orientalis and Quercus variabilis from semiarid areas of northern China were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentration ([CO2]  ×  five soil volumetric water content (SWC. The δ13C of water-soluble compounds extracted from leaves of saplings was determined for an assessment of instantaneous water use efficiency (WUEcp after cultivation. Instantaneous water use efficiency derived from gas-exchange measurements (WUEge was integrated to estimate differences in δ13C signal variation before leaf-level translocation of primary assimilates. The WUEge values in P. orientalis and Q.  variabilis both decreased with increased soil moisture at 35–80 % of field capacity (FC and increased with elevated [CO2] by increasing photosynthetic capacity and reducing transpiration. Instantaneous water use efficiency (iWUE according to environmental changes differed between the two species. The WUEge in P. orientalis was significantly greater than that in Q. variabilis, while an opposite tendency was observed when comparing WUEcp between the two species. Total 13C fractionation at the site of

  8. Use of high-scale traffic modeling to estimate road vehicle emissions of CO2 and impact on the atmospheric concentration in São Paulo, Brazil.

    Science.gov (United States)

    Miranda, R. M.; Perez-Martinez, P.; Andrade, M. D. F.

    2015-12-01

    Adequate estimations of motor vehicle CO2 emission inventories at high spatial and temporal urban scales are needed to establish transport policy measures aim to reduce climate change impacts from global cities. The Metropolitan Region of São Paulo (MRSP) is impacted by the emission of 7 million vehicles (97% light-duty gasoline vehicles LDVs and 3% heavy-duty diesel vehicles HDVs) and several environmental programs were implemented to reduce the emissions. Inventories match site measurements and remote sensing and help to assess the real impact of road vehicle emissions on city's air quality. In this paper we presented a high-resolution vehicle-based inventory of motor CO2 emissions mapped at a scale of 100 m and 1 hour. We used origin and destination (O/D) transport area zone trips from the mobility survey of the São Paulo Transport Metropolitan Company (Metro), a road network of the region and traffic datasets from the São Paulo Transport Engineering Company (CET). The inventory was done individually for LDVs and HDVs for the years 2008 and 2013 and was complemented with air quality datasets from the State Environmental Company (CETESB), together with census data from the Brazilian Institute of Geography and Statistics (IBGE). Our inventory showed partial disagreement with the São Paulo State's GHG inventory, caused by the different approach used - bottom vs. top down - and characteristic spatial and temporal biases of the population inputs used (different emission factors). Higher concentrations became apparent near the road-network at the spatial scale used. The total emissions were estimated in 20,781 million tons per year of CO2eq (83.7% by LDVs and 16.3% HDVs). Temporal profiles - diurnal, weekly and monthly - in vehicle emission distributions were calculated using CET's traffic counts and surrogates of congestion. These profiles were compared with average road-site measurements of CO2 for the year 2013. Measurements showed two peaks associated to the

  9. Short-term treatments with high CO2and low O2concentrations on quality of fresh goji berries (Lycium barbarum L.) during cold storage.

    Science.gov (United States)

    Kafkaletou, Mina; Christopoulos, Miltiadis V; Tsantili, Eleni

    2017-12-01

    Goji berries (Lycium barbarum L.) are functional fruits but are usually marketed as a dried product. The aim of this study was to investigate the storability of fresh goji berries treated with high CO 2 and low O 2 concentrations before air storage at 1 °C for 21 days. Berries harvested without stems were exposed to air (controls) or subjected for 2 days at 1 °C to the following controlled atmosphere (CA) treatments: 21% O 2 + 0% CO 2 (21+0), 5% O 2 + 15% CO 2 (5+15), 10% O 2 + 10% CO 2 (10+10) and 20% O 2 + 20% CO 2 (20+20). During 14 days of storage, all treatments decreased weight loss, while treatments 5+15 and 20+20 prevented fungal decay. No fermentation was observed. The treatments did not affect color changes, decreases in soluble sugars and increases in total soluble solids, titratable acidity, ascorbic acid, total carotenoids, total phenolics and ferric-reducing antioxidant power (FRAP) during storage, apart from the marginally reduced FRAP by treatment 20+20 on day 7. Treatments 5+15, 10+10 and 20+20 resulted in residual decreases in respiration rates and pH values early during storage. After 14 days of storage, panelists rated the CA-treated samples as sweet, with good acceptance. Treatments 5+15 and 20+20 showed the best results after 14 days of storage. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  10. Arrest at metaphase of meiosis I in starfish oocytes in the ovary is maintained by high CO2 and low O2 concentrations in extracellular fluid.

    Science.gov (United States)

    Moriwaki, Kei; Nakagawa, Takako; Nakaya, Fumio; Hirohashi, Noritaka; Chiba, Kazuyoshi

    2013-11-01

    During the spawning process in starfish, oocytes are arrested at metaphase of meiosis I (MI) within the ovary, and reinitiate meiosis only after they have been released into the seawater. However, this arrest does not occur if the ovary is removed from the animal. As the pH of the coelomic fluid is buffered by CO2/H(+)/HCO3(-), we investigated the involvement of gas concentrations in MI arrest. In vivo, the CO2 level in the coelomic fluid was high (∼1.5% vs. 0.04% in air) and the O2 level was low (0.1-1.0% vs. ∼20% in air). When these gas conditions were reproduced in isolated coelomic fluid or seawater, ovarian oocytes arrested at MI, just as in vivo. Isolated oocytes from the ovary required the similar high CO2 and low O2 level to remain arrested in MI and had an intracellular pH of ∼6.9. Intracellular pH increased to ∼7.3 when oocytes were transferred to seawater equilibrated with air, a condition that mimics that of spawning. We used ammonium acetate to clamp intracellular pH at different levels and found that MI arrest occurred when intracellular pH was ∼6.9. Our results support the idea that high CO2 and low O2 in the ovarian environment lead to low intracellular pH and MI arrest, while spawning into the seawater with low CO2 and high O2 results in high intracellular pH and release from MI arrest. The biological significance of MI arrest is that oocytes are spawned into seawater at the optimal physiological state of MI when the least polyspermy occurs.

  11. Driving forces of mid-Holocene vegetation shifts on the upper Tibetan Plateau, with emphasis on changes in atmospheric CO 2 concentrations

    Science.gov (United States)

    Herzschuh, Ulrike; Ni, Jian; Birks, H. John B.; Böhner, Jürgen

    2011-07-01

    Numerous pollen records across the upper Tibetan Plateau indicate that in the early part of the mid-Holocene, Kobresia-rich high-alpine meadows invaded areas formerly dominated by alpine steppe vegetation rich in Artemisia. We examine climate, land-use, and CO 2 concentration changes as potential drivers for this marked vegetation change. The climatic implications of these vegetational shifts are explored by applying a newly developed pollen-based moisture-balance transfer-function to fossil pollen spectra from Koucha Lake on the north-eastern Tibetan Plateau (34.0°N; 97.2°E; 4540 m a.s.l.) and Xuguo Lake on the central Tibetan Plateau (31.97°N; 90.3°E; 4595 m a.s.l.), both located in the meadow-steppe transition zone. Reconstructed moisture-balances were markedly reduced (by ˜150-180 mm) during the early mid-Holocene compared to the late-Holocene. These findings contradict most other records from the Indian monsoonal realm and also most non-pollen records from the Tibetan Plateau that indicate a rather wet early- and mid-Holocene. The extent and timing of anthropogenic land-use involving grazing by large herbivores on the upper Tibetan Plateau and its possible impacts on high-alpine vegetation are still mostly unknown due to the lack of relevant archaeological evidence. Arguments against a mainly anthropogenic origin of Kobresia high-alpine meadows are the discovery of the widespread expansion of obviously 'natural' Kobresia meadows on the south-eastern Tibetan Plateau during the Lateglacial period indicating the natural origin of this vegetation type and the lack of any concurrence between modern human-driven vegetation shifts and the mid-Holocene compositional changes. Vegetation types are known to respond to atmospheric CO 2 concentration changes, at least on glacial-interglacial scales. This assumption is confirmed by our sensitivity study where we model Tibetan vegetation at different CO 2 concentrations of 375 (present-day), 260 (early Holocene), and

  12. Kinetic modeling of hydrogen production rate by photoautotrophic cyanobacterium A. variabilis ATCC 29413 as a function of both CO2 concentration and oxygen production rate.

    Science.gov (United States)

    Salleh, Siti Fatihah; Kamaruddin, Azlina; Uzir, Mohamad Hekarl; Mohamed, Abdul Rahman; Shamsuddin, Abdul Halim

    2017-02-07

    Hydrogen production by cyanobacteria could be one of the promising energy resources in the future. However, there is very limited information regarding the kinetic modeling of hydrogen production by cyanobacteria available in the literature. To provide an in-depth understanding of the biological system involved during the process, the Haldane's noncompetitive inhibition equation has been modified to determine the specific hydrogen production rate (HPR) as a function of both dissolved CO2 concentration (CTOT) and oxygen production rate (OPR). The highest HPR of 15 [Formula: see text] was found at xCO2 of 5% vol/vol and the rate consequently decreased when the CTOT and OPR were 0.015 k mol m(-3) and 0.55 mL h(-1), respectively. The model provided a fairly good estimation of the HPR with respect to the experimental data collected.

  13. The Effect of Saccharomyces Strains and Fermentation Condition on the pH, Foam Property and CO2 Concentration of Non-alcoholic Beer (Ma-al-shaeer

    Directory of Open Access Journals (Sweden)

    S. Sohrabvandi

    2014-12-01

    Full Text Available This study aims to determine the effect of fermentation condition and Saccharomyces strains on the pH, foam property and CO2 concentration of non-alcoholic beer (Ma-al-shaeer. For this, the beer samples were inoculated with four different species of Saccharomyces (Saccharomyces rouxii 70531, S. rouxii 70535, S. ludwigii 3447 and S. cerevisiae 70424 and fermented for 48h in both aerobic and periodic aeration at three different temperatures. Then their pH, CO2 concentration and foam property were analyzed in 12h intervals during 48h fermentation. The results shows that the treatments with 4×107 CFU.ml-1 and periodic aeration at 24˚C showed the greatest decrease in pH, and the treatments with 107 CFU.ml-1 and aerobic-periodic aeration at 4˚C showed the lowest decrease in pH. The highest and lowest amounts of CO2 and foam property were obtained in the treatments with 4×107 CFU.ml-1 inoculation, aerobic condition, and the treatments with 107 CFU.ml-1, periodic aeration, respectively. These results further demonstrated that the highest drop in pH, and the highest ability of producing CO2 and foam were for S. cerevisiae 70424, and the lowest belonged to S. rouxii 70531. The overall outcome of the study points to the fact that physico-chemical properties of Ma-al-shaeer is important from the consumers' point of view. Therefore, S. cerevisiae with 4×107 CFU.ml-1 inoculation and aerobic condition at 4˚C has promising potential for producing Ma-al-shaeer with good physicochemical properties.

  14. Involvement of the cynABDS operon and the CO2-concentrating mechanism in the light-dependent transport and metabolism of cyanate by cyanobacteria.

    Science.gov (United States)

    Espie, George S; Jalali, Farid; Tong, Tommy; Zacal, Natalie J; So, Anthony K-C

    2007-02-01

    The cyanobacteria Synechococcus elongatus strain PCC7942 and Synechococcus sp. strain UTEX625 decomposed exogenously supplied cyanate (NCO-) to CO2 and NH3 through the action of a cytosolic cyanase which required HCO3- as a second substrate. The ability to metabolize NCO- relied on three essential elements: proteins encoded by the cynABDS operon, the biophysical activity of the CO2-concentrating mechanism (CCM), and light. Inactivation of cynS, encoding cyanase, and cynA yielded mutants unable to decompose cyanate. Furthermore, loss of CynA, the periplasmic binding protein of a multicomponent ABC-type transporter, resulted in loss of active cyanate transport. Competition experiments revealed that native transport systems for CO2, HCO3-, NO3-, NO2-, Cl-, PO4(2-), and SO4(2-) did not contribute to the cellular flux of NCO- and that CynABD did not contribute to the flux of these nutrients, implicating CynABD as a novel primary active NCO- transporter. In the S. elongatus strain PCC7942 DeltachpX DeltachpY mutant that is defective in the full expression of the CCM, mass spectrometry revealed that the cellular rate of cyanate decomposition depended upon the size of the internal inorganic carbon (Ci) (HCO3- + CO2) pool. Unlike wild-type cells, the rate of NCO- decomposition by the DeltachpX DeltachpY mutant was severely depressed at low external Ci concentrations, indicating that the CCM was essential in providing HCO3- for cyanase under typical growth conditions. Light was required to activate and/or energize the active transport of both NCO- and Ci. Putative cynABDS operons were identified in the genomes of diverse Proteobacteria, suggesting that CynABDS-mediated cyanate metabolism is not restricted to cyanobacteria.

  15. Involvement of the cynABDS Operon and the CO2-Concentrating Mechanism in the Light-Dependent Transport and Metabolism of Cyanate by Cyanobacteria▿

    Science.gov (United States)

    Espie, George S.; Jalali, Farid; Tong, Tommy; Zacal, Natalie J.; So, Anthony K.-C.

    2007-01-01

    The cyanobacteria Synechococcus elongatus strain PCC7942 and Synechococcus sp. strain UTEX625 decomposed exogenously supplied cyanate (NCO−) to CO2 and NH3 through the action of a cytosolic cyanase which required HCO3− as a second substrate. The ability to metabolize NCO− relied on three essential elements: proteins encoded by the cynABDS operon, the biophysical activity of the CO2-concentrating mechanism (CCM), and light. Inactivation of cynS, encoding cyanase, and cynA yielded mutants unable to decompose cyanate. Furthermore, loss of CynA, the periplasmic binding protein of a multicomponent ABC-type transporter, resulted in loss of active cyanate transport. Competition experiments revealed that native transport systems for CO2, HCO3−, NO3−, NO2−, Cl−, PO42−, and SO42− did not contribute to the cellular flux of NCO− and that CynABD did not contribute to the flux of these nutrients, implicating CynABD as a novel primary active NCO− transporter. In the S. elongatus strain PCC7942 ΔchpX ΔchpY mutant that is defective in the full expression of the CCM, mass spectrometry revealed that the cellular rate of cyanate decomposition depended upon the size of the internal inorganic carbon (Ci) (HCO3− + CO2) pool. Unlike wild-type cells, the rate of NCO− decomposition by the ΔchpX ΔchpY mutant was severely depressed at low external Ci concentrations, indicating that the CCM was essential in providing HCO3− for cyanase under typical growth conditions. Light was required to activate and/or energize the active transport of both NCO− and Ci. Putative cynABDS operons were identified in the genomes of diverse Proteobacteria, suggesting that CynABDS-mediated cyanate metabolism is not restricted to cyanobacteria. PMID:17122352

  16. Searching for a Relationship Between Forest Water Use and Increasing Atmospheric CO2 Concentration with Long-Term Hydrologic Data from the Hubbard Brook Experimental Forest

    Energy Technology Data Exchange (ETDEWEB)

    Amthor, J.S.

    1998-11-01

    Increases in atmospheric C02 concentration from mid-1956 through mid-1997 were compared with hydrologic records from five forested, gaged watersheds in the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, U.S.A. The purpose of the comparison was to assess whether a relationship between increasing atmospheric CO2 concentration and whole-ecosystem evapotranspiration (ET) could be determined. The HBEF is particularly well suited to this type of study because of the length of the hydrologic record and the physical properties of the watersheds. This analysis is based on HBEF water years (which begin 1 June and end the following 31 May) rather than calendar years. Hydrologic records from individual watersheds used in this analysis ranged from 28 to 41 water years. During the full 41-water-year period, it is estimated that water-year mean atmospheric CO2 concentration increased more than 15% (from about 314 to 363 ppm). In one south-facing watershed (i.e., HBEF watershed 3), there was a statistically significant negative relationship between atmospheric C02 concentration and ET. This translated into a nearly 77 rnndyear reduction in ET as a result of a 50 ppm increase in atmospheric C02 concentration, a result of practical significance. Evapotranspiration from the other watersheds was also negatively related to atmospheric CO2 concentration, but with smaller (and statistically insignificant) magnitudes. Evapotranspiration from the three south-facing (but not the two north-facing) watersheds included in the analysis was "abnormally" low during the most recent 2 years (i.e., water years beginning in 1995 and 1996), and this affected the trends in ET. This recent and abrupt, reduction in ET deserves further analysis, most importantly by an extension of the hydrologic record through continued long-term monitoring in the HBEF (which is ongoing). If ET remains relatively low during the coming years in south-facing watersheds, studies of the physical and/or biological

  17. Development of experimental structure and influence of high CO2 concentration in maize cro Desenvolvimento de estrutura experimentale influências da alta concentração de CO2 na cultura do milho

    Directory of Open Access Journals (Sweden)

    João B. Lopes da Silva

    2012-04-01

    Full Text Available Maize is a C4 plant that shows few or no response to high [CO2]. Thus, this study aimed to analyze the photosynthetic rate and yield of maize under high [CO2] and develop open-top chambers (OTC to create an atmosphere enriched with CO2. The experiment was conducted between October 2008 and March 2009. The OTCs were developed in modular scheme. Measurement of photosynthetic rates, transpiration, stomata conductance, grain yield and dry matter were performed. The experimental design was randomized blocks with four replications and three treatments: P1 - plants grown in OTC with 700 ppm [CO2], P2 - plants grown in OTC with environmental [CO2], and P3 - control, cultivated in open field. The results were analyzed by ANOVA and Tukey's test (PrO milho é uma planta C4 que apresenta pouca, ou nenhuma, resposta às elevadas [CO2]; assim, neste trabalho, objetivou-se analisar respostas fisiológicas e produtivas da cultura do milho sob alta [CO2], e desenvolver câmaras de topo aberto (CTA para criar uma atmosfera enriquecida com CO2. O experimento foi conduzido entre outubro de 2008 e março de 2009. As CTAs foram desenvolvidas em esquema modular. Foram realizadas medições da taxa fotossintética, transpiração, condutância estomática, produção de grãos e matéria seca. O delineamento experimental foi em blocos casualizados, com quatro repetições e três tratamentos: P1 - plantas cultivadas em CTA a [CO2] de 700ppm; P2 - plantas cultivadas em CTAcom [CO2] ambiente; e P3 -plantas cultivadas em campo aberto, testemunhas. Os resultados obtidos foram submetidos à análise de variância e teste de Tukey (Pr<0,05. As câmaras reduzem em 25% a Radiação Fotossinteticamente Ativa e aumentam a temperatura do ar e das folhas, em relação ao ambiente externo. As plantas sob alta [CO2] (P1 apresentaram as maiores taxas fotossintéticas e as menores condutâncias estomáticas e transpiração. O peso total dos grãos (g e a matéria seca da parte a

  18. Influences of changing land use and CO 2 concentration on ecosystem and landscape level carbon and water balances in mountainous terrain of the Stubai Valley, Austria

    Science.gov (United States)

    Tenhunen, J.; Geyer, R.; Adiku, S.; Reichstein, M.; Tappeiner, U.; Bahn, M.; Cernusca, A.; Dinh, N. Q.; Kolcun, O.; Lohila, A.; Otieno, D.; Schmidt, M.; Schmitt, M.; Wang, Q.; Wartinger, M.; Wohlfahrt, G.

    2009-05-01

    A process-based spatial simulation model was used to estimate gross primary production, ecosystem respiration, net ecosystem CO 2 exchange and water use by the vegetation in Stubai Valley, Austria at landscape scale. The simulations were run for individual years from early spring to late fall, providing estimates in grasslands for carbon gain, biomass and leaf area development, allocation of photoproducts to the below ground ecosystem compartment, and water use. In the case of evergreen coniferous forests, gas exchange is estimated, but spatial simulation of growth over the single annual cycles is not included. Spatial parameterization of the model is derived for forest LAI based on remote sensing, for soil characteristics by generalization from spatial surveys and for climate drivers from observations at monitoring stations along the elevation gradient and from modelling of incident radiation in complex terrain. Validation of the model was carried out at point scale, and was based on comparison of model output at selected locations with observations along elevation gradients in Stubai Valley and Berchtesgaden National Park, Germany as well as with known trends in ecosystem response documented in the literature. The utility of the model for describing long-term changes in carbon and water balances at landscape scale is demonstrated in the context of land use change that occurred between 1861 and 2002 in Stubai Valley. During this period, coniferous forest increased in extent by ca. 11% of the vegetated area of 1861, primarily in the subalpine zone. Managed grassland decreased by 46%, while abandoned grassland and natural alpine mats increased by 14 and 11%, respectively. At point scale, the formulated model predicts higher canopy conductance in 1861 due to lower atmospheric CO 2 concentration which opens stomata. As a result, water use at point scale decreased by ca. 8% in 2002 in the valley bottoms versus 10% at tree line. At landscape level, the decrease in water

  19. Influence of the interaction between light intensity and CO2 concentration on productivity and quality of spinach (Spinacia oleracea L.) grown in fully controlled environment

    Science.gov (United States)

    Proietti, Simona; Moscatello, Stefano; Giacomelli, Gene A.; Battistelli, Alberto

    2013-09-01

    The effects of the factorial combination of two light intensities (200 and 800 μmol m-2 s-1) and two CO2 concentrations (360 and 800 ppm) were studied on the productivity and nutritional quality of spinach (Spinacia oleracea L.) grown under controlled environment. After 6 weeks within a growth chamber, spinach plants were sampled and analyzed for productivity and quality. There were no statistically significant interactions between the effects of light and CO2 for all of the variables studied, except for the nitrate and oxalic acid content of the leaves. High light and high CO2 independently one from the other, promoted spinach productivity, and the accumulation of ascorbic acid, while their interactive effect limited the accumulation of nitrate and oxalic acid in the spinach leaves. The results highlight the importance of considering the effects of the interaction among environmental variables on maximizing production and the nutritional quality of the food when cultivating and modeling the plant response in controlled environment systems such as for bioregenerative life support.

  20. Aquaporin plays an important role in mediating chloroplastic CO2 concentration under high-N supply in rice (Oryza sativa) plants.

    Science.gov (United States)

    Ding, Lei; Gao, Limin; Liu, Wei; Wang, Min; Gu, Mian; Ren, Binbin; Xu, Guohua; Shen, Qirong; Guo, Shiwei

    2015-09-18

    Our previous studies demonstrated that chloroplastic CO2 concentration (Cc) is not sufficient under high-nitrogen (N) supply in rice plants. In this research, we studied how aquaporins- (AQPs) mediated Cc under different N-supply levels. A hydroponic experiment was conducted in a greenhouse with three different N levels (low N, 0.71 mM; intermediate N, 2.86 mM; and high N, 7.14 mM) in a rice cultivar (Oryza sativa cv. Shanyou 63) and with an ospip1;1 mutant (Oryza sativa cv. Nipponbare). The photosynthetic nitrogen-use efficiency (PNUE) decreased with increasing leaf-N content. Under high-N supply, the estimated Cc was significantly lower than the theoretical Cc and the specific Rubisco activity (carboxylation efficiency/Rubisco content, CE/Rubisco) decreased, because of a decrease of relative CO2 diffusion conductance (total CO2 diffusion conductance/leaf-N content, gt /N) in mesophyll cells. Real Time Quantitative PCR (Q-RT-PCR) showed that most OsPIP1s and OsPIP2s expression were downregulated under the high-N supply. Furthermore, Cc and gm decreased in the ospip1;1 mutant line compared with that of the wild-type plant. It was concluded that under high-N supply, the decreased PNUE was associated with non-sufficient Cc, mediated by AQP in mesophyll conductance. © 2015 Scandinavian Plant Physiology Society.

  1. Photoassimilation, Assimilate Translocation and Plasmodesmal Biogenesis in the Source Leaves of Arabidopsis thaliana Grown Under an Increased Atmospheric CO2 Concentration

    Science.gov (United States)

    Duan, Zhongrui; Homma, Ayumi; Kobayashi, Megumi; Nagata, Noriko; Kaneko, Yasuko; Fujiki, Yuki; Nishida, Ikuo

    2014-01-01

    Using 18-day-old Arabidopsis thaliana seedlings grown under increased (780 p.p.m., experimental plants) or ambient (390 p.p.m., control plants) CO2 conditions, we evaluated 14CO2 photoassimilation in and translocation from representative source leaves. The total 14CO2 photoassimilation amounts increased in the third leaves of the experimental plants in comparison with that found for the third leaves of the control plants, but the rates were comparable for the first leaves of the two groups. In contrast, translocation of labeled assimilates doubled in the first leaves of the experimental group, whereas translocation was, at best, passively enhanced even though photoassimilation increased in their third leaves. The transcript levels of the companion cell-specific sucrose:H+ symporter gene SUC2 were not significantly affected in the two groups of plants, whereas those of the sucrose effluxer gene SWEET12 and the sieve element-targeted sucrose:H+ symporter gene SUT4 were up-regulated in the experimental plants, suggesting up-regulation of SUT4-dependent apoplastic phloem loading. Compared with SUC2, SUT4 is a minor component that is expressed in companion cells but functions in sieve elements after transfer through plasmodesmata. The number of aniline blue-stained spots for plasmodesma-associated callose in the midrib wall increased in the first leaf of the experimental plants but was comparable in the third leaf between the experimental and control plants. These results suggest that A. thaliana responds to greater than normal concentrations of CO2 differentially in the first and third leaves in regards to photoassimilation, assimilate translocation and plasmodesmal biogenesis. PMID:24406629

  2. Evidence that inducible C-4-type photosynthesis is a chloroplastic CO2-concentrating mechanism in Hydrilla, a submersed monocot

    NARCIS (Netherlands)

    Reiskind, JB; Madsen, TV; VanGinkel, LC; Bowes, G

    Hydrilla verticillata (L.f.) Royle exhibits an inducible C-4- type photosynthetic cycle, but lacks Kranz anatomy. Leaves in the C-4-type state (but not C-3-type) contained up to 5-fold higher internal dissolved inorganic carbon (DIG) concentrations than the medium, indicating that they possessed a

  3. Absolute accuracy and sensitivity analysis of OP-FTIR retrievals of CO2, CH4 and CO over concentrations representative of "clean air" and "polluted plumes"

    Directory of Open Access Journals (Sweden)

    D. W. T. Griffith

    2011-01-01

    Full Text Available When compared to established point-sampling methods, Open-Path Fourier Transform Infrared (OP-FTIR spectroscopy can provide path-integrated concentrations of multiple gases simultaneously, in situ and near-continuously. The trace gas pathlength amounts can be retrieved from the measured IR spectra using a forward model coupled to a non-linear least squares fitting procedure, without requiring "background" spectral measurements unaffected by the gases of interest. However, few studies have investigated the accuracy of such retrievals for CO2, CH4 and CO, particularly across broad concentration ranges covering those characteristic of ambient to highly polluted air (e.g. from biomass burning or industrial plumes. Here we perform such an assessment using data collected by a field-portable FTIR spectrometer. The FTIR was positioned to view a fixed IR source placed at the other end of an IR-transparent cell filled with the gases of interest, whose target concentrations were varied by more than two orders of magnitude. Retrievals made using the model are complicated by absorption line pressure broadening, the effects of temperature on absorption band shape, and by convolution of the gas absorption lines and the instrument line shape (ILS. Despite this, with careful model parameterisation (i.e. the optimum wavenumber range, ILS, and assumed gas temperature and pressure for the retrieval, concentrations for all target gases were able to be retrieved to within 5%. Sensitivity to the aforementioned model inputs was also investigated. CO retrievals were shown to be most sensitive to the ILS (a function of the assumed instrument field-of-view, which is due to the narrow nature of CO absorption lines and their consequent sensitivity to convolution with the ILS. Conversely, CO2 retrievals were most sensitive to assumed atmospheric parameters, particularly gas temperature. Our findings provide confidence that FTIR-derived trace gas retrievals of CO2, CH4 and CO

  4. Estimated lag time in global carbon emissions and CO2 concentrations produced by commercial nuclear power through 2009 with projections through 2030.

    Science.gov (United States)

    Coleman, Neil M; Abramson, Lee R; Coleman, Fiona A B

    2012-03-01

    This study examines the past and future impact of nuclear reactors on anthropogenic carbon emissions to the atmosphere. If nuclear power had never been commercially developed, what additional global carbon emissions would have occurred? More than 44 y of global nuclear power have caused a lag time of at least 1.2 y in carbon emissions and CO2 concentrations through the end of 2009. This lag time incorporates the contribution of life cycle carbon emissions due to the construction and operation of nuclear plants. Cumulative global carbon emissions would have been about 13 Gt greater through 2009, and the mean annual CO2 concentration at Mauna Loa would have been ~2.7 ppm greater than without nuclear power. This study finds that an additional 14–17 Gt of atmospheric carbon emissions could be averted by the global use of nuclear power through 2030, for a cumulative total of 27–30 Gt averted during the period 1965–2030. This result is based on International Atomic Energy Agency projections of future growth in nuclear power from 2009–2030, modified by the recent loss or permanent shutdown of 14 reactors in Japan and Germany

  5. A new method to estimate photosynthetic parameters through net assimilation rate-intercellular space CO2 concentration (A-Ci ) curve and chlorophyll fluorescence measurements.

    Science.gov (United States)

    Moualeu-Ngangue, Dany P; Chen, Tsu-Wei; Stützel, Hartmut

    2017-02-01

    Gas exchange (GE) and chlorophyll fluorescence (CF) measurements are widely used to noninvasively study photosynthetic parameters, for example the rates of maximum Rubisco carboxylation (Vcmax ), electron transport rate (J), daytime respiration (Rd ) and mesophyll conductance (gm ). Existing methods for fitting GE data (net assimilation rate-intercellular space CO2 concentration (A-Ci ) curve) are based on two assumptions: gm is unvaried with CO2 concentration in the intercellular space (Ci ); and light absorption (α) and the proportion of quanta absorbed by photosystem II (β) are constant in the data set. These may result in significant bias in estimating photosynthetic parameters. To avoid the above-mentioned hypotheses, we present a new method for fitting A-Ci curves and CF data simultaneously. This method was applied to a data set obtained from cucumber (Cucumis sativus) leaves of various leaf ages and grown under eight different light conditions. The new method had significantly lower root mean square error and a lower rate of failures compared with previously published methods (6.72% versus 24.1%, respectively) and the effect of light conditions on Vcmax and J was better observed. Furthermore, the new method allows the estimation of a new parameter, the fraction of incoming irradiance harvested by photosystem II, and the dependence of gm on Ci . © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  6. Enhancement of the Stomatal Response to Blue Light by Red Light, Reduced Intercellular Concentrations of CO(2), and Low Vapor Pressure Differences.

    Science.gov (United States)

    Assmann, S M

    1988-05-01

    The effects of environmental parameters on the blue light response of stomata were studied by quantifying transient increases in stomatal conductance in Commelina communis following 15 seconds by 0.100 millimole per square meter per second pulses of blue light. Because conductance increases were not observed following red light pulses of the same or greater (30 seconds by 0.200 millimole per square meter per second) fluences, the responses observed could be reliably attributed to the specific blue light response of the guard cells, rather than to guard cell chlorophyll. In both Paphiopedilum harrisianum, which lacks guard cell chloroplasts, and Commelina, the blue light response was enhanced by 0.263 millimole per square meter per second continuous background red light. Thus, the blue light response and its enhancement do not require energy derived from red-light-driven photophosphorylation by the guard cell chloroplasts. In Commelina, reduction of the intercellular concentration of CO(2) by manipulation of ambient CO(2) concentrations resulted in an enhanced blue light response. In both Commelina and Paphiopedilum, the blue light response was decreased by an increased vapor pressure difference. The magnitude of blue-light-specific stomatal opening thus appears to be sensitive to environmental conditions that affect the carbon and water status of the plant.

  7. Enhancement of the Stomatal Response to Blue Light by Red Light, Reduced Intercellular Concentrations of CO2, and Low Vapor Pressure Differences 1

    Science.gov (United States)

    Assmann, Sarah M.

    1988-01-01

    The effects of environmental parameters on the blue light response of stomata were studied by quantifying transient increases in stomatal conductance in Commelina communis following 15 seconds by 0.100 millimole per square meter per second pulses of blue light. Because conductance increases were not observed following red light pulses of the same or greater (30 seconds by 0.200 millimole per square meter per second) fluences, the responses observed could be reliably attributed to the specific blue light response of the guard cells, rather than to guard cell chlorophyll. In both Paphiopedilum harrisianum, which lacks guard cell chloroplasts, and Commelina, the blue light response was enhanced by 0.263 millimole per square meter per second continuous background red light. Thus, the blue light response and its enhancement do not require energy derived from red-light-driven photophosphorylation by the guard cell chloroplasts. In Commelina, reduction of the intercellular concentration of CO2 by manipulation of ambient CO2 concentrations resulted in an enhanced blue light response. In both Commelina and Paphiopedilum, the blue light response was decreased by an increased vapor pressure difference. The magnitude of blue-light-specific stomatal opening thus appears to be sensitive to environmental conditions that affect the carbon and water status of the plant. PMID:16666108

  8. CO2 blood test

    Science.gov (United States)

    Bicarbonate test; HCO3-; Carbon dioxide test; TCO2; Total CO2; CO2 test - serum; Acidosis - CO2; Alkalosis - CO2 ... The CO2 test is most often done as part of an electrolyte or basic metabolic panel. Changes in your ...

  9. 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